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7787845
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Microsomal juvenile hormone binding proteins in the follicle cells of Tenebrio molitor.
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The microsomal fraction of Tenebrio molitor follicle cells has been found to contain both high and low affinity binding sites for juvenile hormone (JH) III. Using Scatchard analysis, the equilibrium dissociation constants, Kd, were calculated as 1.0 x 10(-8) and 4.3 x 10(-7) M respectively. Kinetic data support a rapid binding of the hormone to the site(s), with rate constants of ka = 3.77 x 10(8) M-1 min-1 and kd = 0.0075 min-1. Affinity of the binding site(s) for JH III was higher than for either JH I or methoprene. The significance and possible function of such microsomal binding proteins are discussed, with reference to the perturbance of vitellogenesis found in beetles parasitized by Hymenolepis diminuta.
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7787842
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Multiple phosphorylation of ribosomal protein S6 and specific protein synthesis are required for prothoracicotropic hormone-stimulated ecdysteroid biosynthesis in the prothoracic glands of Manduca sexta.
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Prothoracicotropic hormone (PTTH)-stimulated protein phosphorylation leads to ecdysteroidogenesis (molting hormone biosynthesis) in the prothoracic glands of the tobacco hornworm, Manduca sexta. The phosphorylation of 34 and 50 kDa peptides (p34 and p50) paralleled the increase in ecdysteroidogenesis, and the dephosphorylation of p34 and p50 preceded a decrease in ecdysteroidogenesis. Inhibition by rapamycin of p34, but not p50, phosphorylation prevented PTTH-stimulated ecdysteroidogenesis in a dose-dependent manner, suggesting that p34 phosphorylation is requisite for PTTH-stimulated ecdysteroidogenesis. Two proteins whose synthesis was rapidly stimulated by PTTH were p50 and p70. The time-course of PTTH-stimulated synthesis of p50 paralleled that of p34 phosphorylation and that of ecdysteroidogenesis. Rapamycin inhibited PTTH-stimulated synthesis of p50 and p70, suggesting that specific protein synthesis is also required for PTTH-stimulated ecdysteroidogenesis, confirming the results of Rybczynski and Gilbert [(1994) Insect Biochem. Molec. Biol. 24, 175-189], and that p34 phosphorylation may regulate the downstream synthesis of p50 and p70, possible key regulatory proteins leading to ecdysteroidogenesis. Results from two-dimensional (2D)-PAGE analysis of the ribosomal proteins purified from prothoracic glands, demonstrated that p34 is indeed ribosomal S6, and is phosphorylated at up to five sites (P1-5) upon PTTH stimulation. The multiple phosphorylation of S6 was inhibited completely by rapamycin as shown in 2D gel maps, further confirming that p34 is ribosomal protein S6. Temporal analysis of PTTH-stimulated S6 phosphorylation by 2D-PAGE revealed that phosphorylation of S6 at the P1 site was temporally correlated with the initiation of ecdysteroidogenesis, and that multiple phosphorylation at all five sites (P1-5) was correlated with the maximal synthesis of ecdysteroids. Dephosphorylation of S6 was accompanied by a decrease in ecdysteroidogenesis. These data demonstrate that p34 is ribosomal protein S6 and that both the phosphorylation of S6 and specific protein synthesis are required for PTTH-stimulated ecdysteroidogenesis in the prothoracic gland.
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7787840
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Biotin-containing proteins of the insect nervous system, a potential source of interference with immunocytochemical localization procedures.
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When the biotinylated Manduca sexta adipokinetic hormone gene was used as a probe for in situ hybridization, the intrinsic neurosecretory cells were stained with a biotin detection system that contained streptavidin or avidin. Further experiments showed that the DNA probe was not necessary for staining these cells by streptavidin-alkaline phosphatase, and that they were not stained by alkaline phosphatase alone. Similarly, the intrinsic neurosecretory cells were stained directly by streptavidin conjugated to a fluorescent dye. Other parts of the central nervous system could also be stained with streptavidin-alkaline phosphatase but not as readily as the intrinsic neurosecretory cells of the corpora cardiaca. Further analysis demonstrated three biotin-containing proteins in the intrinsic neurosecretory cells of the corpora cardiaca and in the brain. The most abundant of these proteins, when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, was found to have a molecular weight of 130,000, which is the size of the subunits of pyruvate carboxylase, a biotin-containing enzyme. The same protein was recognized by an antiserum against an insect pyruvate carboxylase, indicating that this protein is probably pyruvate carboxylase. The results reported here indicate that the intrinsic neurosecretory cells of the corpora cardiaca may contain pyruvate carboxylase in a concentration higher that other cells of the central nervous system. We also note that caution is necessary to avoid false positive results if an avidin containing detection system is used for in situ hybridization or immunocytochemistry.
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7787841
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Synthetic pheromone biosynthesis activating neuropeptide gene expressed in a baculovirus expression system.
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A synthetic gene of the pheromone biosynthesis activating neuropeptide (PBAN) of corn earworm Helicoverpa zea, with and without a signal sequence of the cuticle protein of Drosophila melanogaster, was cloned behind the polyhedrin promoter of AcMNPV. Two recombinant baculoviruses were constructed and used to infect a number of insect cell lines including Sf9 and 5B1-4. High pheromonotropic activity was consistently obtained from 5B1-4 cell culture that was infected with the recombinant baculovirus vINV-4 containing the signal sequence. The PBAN gene-product was isolated by HPLC and analyzed by electrospray ionization mass spectrometry. Low levels of biological activity obtained from Sf9 cells infected with the recombinant virus vPBAN may be due to lack of proper amidation at the C-terminus of the expressed peptide or rapid proteolytic degradation of the product.
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7787839
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Subpopulations in closed-head injury: preliminary results.
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The classification systems currently utilized to categorize closed-head injury (CHI) patients are all based on severity levels. However, these scales are unable to account for the wide variability among CHI patients. Another way to classify these patients is to use the clinical picture independent of the overall severity level. That approach is used with aphasic patients but not with the CHI population. These preliminary data indicate that there are distinct subgroups in the CHI population. These subgroups can be identified by their overall pattern of performance on a battery of tests covering language, memory, visuospatial, cognitive and discourse skills. The characteristics of the tentative subgroups are described, but a more extensive study is needed to confirm the robustness of this classification.
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7787838
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Head injuries in the elderly.
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Two hundred and sixty-three consecutive head-injured patients aged over 65 years, admitted to a neurosurgical service, are reported. In contrast to younger age group the main cause was falls concomitant with a high rate of cardiovascular pre-existing disorders. The distribution of causes and grim results justify, in our opinion, regarding head injury in the elderly as a distinct entity requiring special surgical, medical, organizational and ethical considerations.
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7787837
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Developmental models of social cognition in assessing the role of family stress in relatives' predictions following traumatic brain injury.
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The present study extended the utilization of developmental models of social cognition to the investigation of stress and relatives' perception of traumatic brain injury (TBI) survivors. Structured interviews were conducted with 21 TBI survivors utilizing interpersonal negotiation strategies (INS) and self understanding (self) in the framework of Selman's model of social perspective-taking and Damon and Hart's multidimensional model of self understanding. A relative group composed of 21 participants was interviewed and their predictions of the responses of the TBI survivors to the action domain of the INS stories were obtained. The relative participant group was also administered the Beck Anxiety and Depression Inventories and Leeds Scales of Depression and Anxiety. The relationships among relative groups' predictive scores, INS and self domains and stress levels were analysed. The result of the survivor groups responses on INS and self were in agreement with the previous findings that TBI survivors respond at psychosocially immature levels. Comparison of INS action scores obtained by the survivor group and predicted by relative group were within one developmental level of each other in 87.4% of the cases. Fifty-two per cent of the relative group scored in mild to moderate or greater depression and 48% scored in the mild to moderate range of anxiety on the Beck scales. Person correlation coefficients indicated significant negative correlations between Beck scores and predictive INS scores. ANOVA indicated significantly higher Beck depression scores in relatives of TBI survivors living in residential facilities than relatives of TBI survivors in an outpatient treatment programme. The study supports the view that developmental social cognition methods appear to advance our understanding of psychosocial adjustments and relatives' perceptions of social cognition in TBI survivors.
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7787836
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Perseveration. Part II: A study of perseveration in closed-head injury.
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This study examines the nature and extent of perseveration in 15 individuals with closed-head injury (CHI) by (a) identifying and describing the types of perseveration that occurred on verbal and non-verbal tasks, (b) examining the possible underlying neuropsychological mechanisms of perseverative behaviour and (c) exploring neuroanatomical correlates of perseveration. Performance of the 15 CHI patients was compared with 15 neurologically normal subjects matched for sex, age, handedness and educational level. The CHI subjects produced significantly more perseverations than did normals, and 'recurrent' perseveration was the most frequently occurring type. A test of verbal learning elicited the greatest number of recurrent perseverations. Overall test performance of the CHI group suggested that memory dysfunction and impaired attention were most likely responsible for perseverative errors. CT scan analyses showed that the three most perseverative CHI subjects evidenced left temporal lobe damage.
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7787834
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Self-reported social networks and interpersonal support 2 years after severe traumatic brain injury.
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Fifty-four patients with traumatic brain injury (TBI) consecutively admitted to a rehabilitation hospital were examined 2 years post-injury. Social interaction and support, subjective complaints, and functional status were assessed. A large variability in social interaction and support patterns was found. Most patients had more interaction and received more support from family members than from friends and neighbours. Thirty-one patients (57.4%) reported that their social networks had markedly declined subsequent to injury. Relatively short duration of coma (< 1 week) and severe sequelae in terms of low functional status and poor emotional adjustment at follow-up, especially in terms of deficits in initiating behaviour, were found to be related to little interaction and support. The importance of both provider and patient initiative in order to establish and preserve a social support network is suggested, and clinical implications briefly discussed.
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7787835
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Perseveration. Part I: a review.
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Perseveration refers to the inappropriate continuation or repetition of a response or activity. It is associated with a variety of neurological disorders and, when pronounced, is thought to be pathognomonic of brain damage. Perseveration manifests itself in several different forms which have had various labels applied, and many hypotheses have been proposed to explain the mechanisms underlying these perseverative behaviours. In this article we review descriptions and classifications of perseveration as it occurs in various neurological disorders, and then discuss some of the neurobehavioural and neuropathological mechanisms thought to account for it.
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7787833
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Self-concept, marital vulnerability and brain damage.
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The present study investigated the influence of a man's brain injury on both his and his wife's self-concept and perception of marital vulnerability. Thirty-six couples in which the husbands had brain damage and twenty-nine couples without disability filled out the Tennessee Self-concept Scale [1], and the Marital Vulnerability Scale [2]. Marital vulnerability of husbands with brain damage was found not to differ from that of the husbands in the control group. However, the marital vulnerability of the wives of the former husbands was lower than that of the other wives. Both men with brain damage and their wives exhibited a decrease in self-esteem and an increase in conflict and pathology. Brain damage appears to affect both the extent and direction of the relations between aspects of the self-concept and marital vulnerability differentially for husbands with brain damage and their wives. Practical and theoretical implications of the negative impact of brain damage upon the person with the damage, upon his wife, and upon their marital relationship are discussed.
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7787831
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D1 receptors modulate striatal dopamine release induced by the stimulation of both D1 and D2 receptors: in vivo voltammetric data revisited.
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Here we re-examine previous data that demonstrated lasting effects of the selective D1 receptor agonist SKF 38393, the selective D2 receptor agonist LY 171555, and of mixed SKF 39383 + LY 171555 upon striatal DA release. We demonstrate that the administration of mixed SKF 38393 + LY 171555 and of SKF 38393 administered alone induced similar time-course effects upon striatal DA release that showed significant parallel developments. We discuss these data in the light of the current literature and we suggest that D1 receptors could play a modulating role on the striatal DA activity and the release of DA in the caudate-putamen.
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7787832
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Cognitive moderators of outcome following traumatic brain injury: a conceptual model and implications for rehabilitation.
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This paper presents a conceptual model describing the relationships between quality of life outcomes following traumatic brain injury (TBI), coping patterns, and beliefs regarding self-efficacy to assist health-care professionals in understanding the complexity of social and psychological sequelae of TBI. The mode hypothesizes that long-lasting cognitive, behavioural, emotional psychiatric, and interpersonal after-effects of TBI may create a real life 'learned helplessness' with consequent deficits in coping, and altered locus of control beliefs. As a result, TBI patients are at risk for developing self-limiting belief systems about their effectiveness in altering significant events that may result in over-generalizing the effects that TBI has in their day-to-day lives. Subsequently, a feedback loop may be set up where their beliefs in not being able to influence outcomes are not tested, life chances are further restricted, outcomes are suboptimal, and quality of life is reduced. The clinical and theoretical implications of this model are discussed, and an expanded model with future research directions is suggested.
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7787830
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Estrogen-receptor occurrence in the female mouse brain: effects of maternal experience, ovariectomy, estrogen and anosmia.
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Maternal behavior (ultrasound-induced pup-searching and retrieving) was studied in eight groups of female house mice with various hormonal backgrounds, experience with pups and function of the olfactory system. In their brains, estrogen receptor immunoreactive (ER-IR) cells were localized and quantified. All animals of all groups had ER-IR cells in a 'reliable subset' of brain areas, the medial preoptic area (MPOA) and ventromedial (VMH) and arcuate nucleus (ARH) of the hypothalamus. In another subset of brain areas, the anterior hypothalamic area (AHA) and cortical (CA) and medial (MA) amygdaloid nucleus, ER-IR cells can be expected in at least some animals of all experimental groups ('expected subset'). In a variable subset of additional brain areas (bed nucleus of the stria terminalis, BNST; suprachiasmatic nucleus, SC; lateral septal nuclei, LS; paraventricular nucleus of the hypothalamus, PVH; entorhinal and piriform cortex, ENT, PIR; subiculum, SUB; hippocampus, HPC; periventricular gray of the midbrain, PVG), ER-IR cells occurred only in some animals of some groups. Numbers of ER-IR cells in a given brain area, volumes occupied by these cells, and cell densities varied considerably among the groups. A covariation of cell counts and volumes was significant for most brain areas indicating that increases of numbers of ER-IR cells relate mainly to volume increases within a given brain area. Experience with pups correlated with an increase of ER presence in the AHA, VMH, ENT, PIR, SUB, HPC and PVG, however, only in the presence of estrogen. Estrogen and pup-experience together led to an increased ER presence in mainly the VMH, ENT and PIR, however, only in females with intact olfaction. Full maternal behavior (retrieving, ultrasound recognition) occurred after the high pregnancy- or experience-induced ER content was reduced to lower levels. The ER occurrence in lactating and experienced virgin females differed, however, in the AHA, BNST, SC, PVH, ENT, PIR, SUB, HPC and PVG showing that the maintenance of maternal behavior can run under different profiles of ER content in the brain. Ovariectomy and/or prolonged high blood-estrogen levels correlated significantly with decreased levels of ER-IR cells in most brain areas which could not be increased by pup-experience.
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7787829
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Neural network models of cortical functions based on the computational properties of the cerebral cortex.
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We describe a biologically plausible modelling framework based on the architectural and processing characteristics of the cerebral cortex. Its key feature is a multicellular processing unit (cortical column) reflecting the modular nature of cortical organization and function. In this framework, we describe a neural network model organization and function. In this framework, we describe a neural network model of the neuronal circuits of the cerebral cortex that learn different functions associated with different parts of the cortex: 1) visual integration for invariant pattern recognition, performed by a cooperation between temporal and parietal areas; 2) visual-to-motor transformation for 3D arm reaching movements, performed by parietal and motor areas; and 3) temporal integration and storage of sensorimotor programs, performed by networks linking the prefrontal cortex to associative sensory and motor areas. The architecture of the network is inspired from the features of the architecture of cortical pathways involved in these functions. We propose two rules which describe neural processing and plasticity in the network. The first rule (adaptive tuning if gating) is an analog of operant conditioning and permits to learn to anticipate an action. The second rule (adaptive timing) is based on a bistable state of activity and permits to learn temporally separate events forming a behavioral sequence.
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7787828
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A behavioral and electrophysiological study of the comparison of size-discrepant shapes.
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An experiment was performed to find an electrophysiological correlate of the way objects of different sizes are perceived as identically shaped. The subjects were presented with pairs of geometrical figures and were instructed to decide whether the two polygons of a pair were identical in shape regardless of size. In addition to event-related potentials (ERPs), reaction times and error rates were recorded. Reaction times increased approximately linearly with increasing size ratios. The subtraction between the ERPs of 'test' and 'control' conditions showed two main activities: a positivity localized on the occipitotemporal scalp areas in the 200-450 ms range, and a negativity localized on the posterior scalp areas in the 500-750 ms range. These different results were discussed with respect to size ratio.
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7787827
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Distribution and metabolism patterns of plasma 7S- and beta-NGF in the adult male rat.
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There is a great deal of controversy on the existence of NGF in body fluids and tissues. To date it remains unknown whether this peptide accumulates preferentially at significant levels in different organs. Thus we undertook the evaluation of kinetic parameters of the disappearance of blood of 125I-7S-NGF and 125I-beta-NGF after intravenous injection in male adult rats. Our results indicate that the plasma half-life of 125I-7S-NGF is approximately twice as long as for 125I-beta-NGF (respectively 61.7 +/- 11.7 min and 36.3 +/- 2.2 min) while the distribution volume is not significantly different between both peptides. Furthermore, the uptake of radioactive NGF by different tissues seems very low as shown by 125I-7S-NGF and 125I-beta-NGF content of the sampled organs compared to the plasma concentration at the same time. These results indicate that the tissue uptake of circulating 7S and beta-NGF is very low in the adult rat. Thus in these animals NGF did not cross the blood-brain barrier and did not accumulate in peripheral organs which are known to contain subsequent amounts of this peptide. This lack of deposition might be due to a binding with plasma proteins (probably alpha 2-macroglobulin).
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7787826
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Exposure and impact assessment of emissions from mercury recycling using domestic rabbits.
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A biomonitoring study using domestic rabbits (Chinchilla) aimed at the exposure and impact risks assessment of emissions released into the ambient air from a mercury-recycling plant has been carried out. Groups of rabbits were exposed to the emissions during 6 months at biomonitoring stations built up in two localities (Rudnany and Matejovce) in the distance of about 3 and 6 km around and downwind from the mercury-producing plant. The aim of the biomonitoring was to trace the translocation of inhaled inorganic Hg in body tissues and the immunotoxic impact of the emissions in the exposed mammalian organism in comparison to a non-exposed animals living outside the polluted area. The content of mercury (as a major pollutant in the ambient air in that area) in body tissues was done spectrometrically using a Trace Mercury Analyser TMA-254. Content of mercury and the other metals in the rabbits' hairs was determined by neutron activation analysis. A statistically significant increase of the inorganic Hg content in the specimens of kidneys, lungs, liver, thigh bone, heart muscle and brain was observed. Concerning the hairs, a statistically significant elevation of Hg and other elements (As, Cd, La, Zn, Na, K, W, Sr) has been found. The body tissue reaction to the increased accumulation of mercury has been investigated by a direct immunofluorescent method to search for body tissue immune complexes. The significant increase of Hg content determined in the organs (especially in kidneys and liver) of the exposed animals was also traced by the presence of immunofluorescent antibodies. In addition, the immunofluorescent antibodies in the myocardium have been proved.(ABSTRACT TRUNCATED AT 250 WORDS)
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7787825
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The prevalence of environmental mycobacteria in drinking water supply systems in Olomouc County, north Moravia, Czech Republic, in the period 1984-1989.
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The presence of environmental mycobacteria was studied in drinking water supply systems in Olomouc County, Czech Republic, in order to detect the possible spread of M. kansasii from the neighbouring region in Ostrava County. Drinking water samples from water supply systems of 16 localities were investigated. The samples of running water, and tap swabs or tap scrapings were collected twice a year, in the spring and in the autumn. The most common cultivated and identified species were M. gordonae (20.4%), M. flavescens (13.8%), rapidly growing mycobacteria (5.0%) and then by occasional identification of M. fortuitum, M. terrae, M. scrofulaceum. M. kansasii was not detected. The prevalence rates showed no time trend over the period 1984-1989. We conclude that there is no evidence at present that endemic M. kansasii, isolated repeatedly from neighbouring region, has spread to Olomouc County. Different environmental and nutritional constituents in soil and coal mine dust in the endemic regions seem to be the most probable limiting environmental factor of the endemic occurrence of M. kansasii in its endemic locality in Ostrava and Karviná regions.
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7787824
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Natural foci of tick-borne encephalitis in central Europe and the relationship of the incidence of Ixodes ricinus to original ecosystems.
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Based on reports of the national epidemiological service on tick-borne encephalitis (TBE) morbidity in 1953-1987, data in the literature, and results of the author's own field research on the occurrence of the common tick, Ixodes ricinus, foci of this disease have been identified on the territory of Czechoslovakia. In Bohemia a significant focus of TBE in the Central Bohemian Region is located in the Krivoklát area with forests and in the Berounka, mid-Vltava, and lower-Sázava river basins, in the Brdy area and the Czech Karst continuing southwards via the Vltava basin to foci in the South Bohemian region in the districts of Písek and Ceské Budĕjovice and west of the Berounka river basin to a focus in the central part of the West Bohemian region. In the North Bohemian and East Bohemian regions only smaller isolated foci of TBE were detected. In Moravia foci of TBE are in the districts of Opava and Bruntál in the North Moravian region and in the central and southern areas of the South Moravian region. The foci in Bohemia are isolated from foci in neighboring countries, those of Moravia are connected with foci in Poland and Austria. On the territory of the Czech Republic foci of TBE are found in localities of pristine oakwood agglomerations. Original beechwood agglomerations even when located below the upper limit of occurrence of the common tick, i.e. less than 700 meters above sea level, do not offer favourable conditions for this arthropod and they do not harbour natural foci of TBE.(ABSTRACT TRUNCATED AT 250 WORDS)
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7787823
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A resistance of head lice (Pediculus capitis) to permethrin in Czech Republic.
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An outbreak of pediculosis at primary schools was recorded in the Czech Republic in 1992. Almost 20% of children in some schools were infested. This outbreak can be attributed to the resistance of head lice to permethrin, which has not been mentioned in literature yet. The resistance factors established in three towns range between 2 and 385 and between 5 and 557 for LC50 and LC90 values, respectively. This resistance has developed after exclusive use of pyrethroids lotion and shampoo in the Czech Republic since 1978, and it was accompanied by a cross-resistance to d-phenothrin and bioalethrin. But the susceptibility of head lice to malathion and pirimiphos-methyl in 1992 was very similar to that found in 1981. The lotion containing 0.3% of malathion (Diffusil H92 M) has been fully effective against the resistant lice. When introduced into the practice, it quickly reduced the infestation of children in primary schools. The other lotion and shampoo containing 0.3% and 0.7% of pirimiphos-methyl respectively were found to be effective as well.
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7787822
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Industrialization and environmental health in Poland.
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There has been enormous pollution and biodegradation of environment in Poland as the consequence of industrialization developed regardless the principles of sustainable development. In the recent years, the decrease of total emission of air pollution caused by gases and dust, the decrease of emission of unprocessed sewage and industrial waste can be seen. These facts are the consequences of economic recession which have appeared in Poland along with economic transformation. However, there is still significant escalation of environmental pollution, in so-called areas of ecological hazards. There are heavily industrialized and urbanized areas covering about 10% of the total country area but inhabited by over 30% of the total country population. The significant environmental pollution goes together with deterioration of the country's health situation what can be seen in shortening the average lifetime expectancy, increased frequency of cardiovascular diseases and cancers and higher infants death rate in comparison to other European countries. Considering the complexity of the factors affecting the population's health status, the basis of the health and environmental policy conceived in order to stop and alter the unwanted health condition tendencies and the environmental quality have been shown here.
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7787821
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Effect of stressful environmental factors upon neonatal immune system.
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To examine the effects of stressful environmental conditions upon the immune system of the newborn (neonates), we analyzed the neonatal serum immunoglobulin levels in a total of 67 neonates from tribal families living in a rural community of eastern India. These cases were grouped into three categories, based upon the predominance of one of the three factors being analyzed, and the reasonable absence of the other two factors. The three factors as determined by the prevailing environmental conditions, which were the basis for forming the three groups, were: 1. indoor air pollution; 2. hygienic conditions, and 3. the cohabitation of domesticated animals in the same household as the infants's families. Presence of indoor air pollution or unhygienic conditions resulted in the disturbance and depression of the levels of serum immunoglobulins of different classes. There was no discernible correlation found between the levels of immunoglobulins of different classes from the neonates (except IgM) and the cohabitation of domesticated animals in the same households. However the incidence of GIT and RT infections was higher in all the three experimental groups, as compared to the control group. These results suggest that unfavorable environmental conditions can adversely affect the immune system at neonatal stages, and can increase their susceptibility to subsequent acute or chronic events.
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7787820
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Salmonellae in gulls and other free-living birds in the Czech Republic.
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Cloacal swabs, collected from 756 wild synanthropic and exoanthropic birds of 57 species in the Czech Republic, yielded 32 strains of Salmonella typhimurium [phage types (PT) 141, 104 and 41], six isolates of S. enteritidis (PT 8, 4 and 6e), and one each of S. panama and S. anatum. Except for one S. enteritidis isolate from a grey-lag goose (Anser anser) and one S. typhimurium isolate from a coot (Fulica atra), all of the other strains were derived from black-headed gulls (Larus ridibundus), of which 24.7% were found to be infected. The black-headed gull might play a role in the dispersal of pathogenic salmonellae.
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7787819
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Cohort study of the relationship between air pollution and short term health effects as determined by peak expiratory flow measurements.
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The aim of the study was to establish if air pollution has short term effects on health and well-being for individuals living in an industrialized area of Norway. A cohort study was designed so that two groups (one randomly selected from the general population and one with preexisting lung disease) were followed hour by hour during two months in the winter and in the summer of 1988. In order to minimize the problems of confounding factors, each individual served as her/his own control. Each participant described through the use of a diary the presence of symptoms from the upper and lower respiratory tract as well as general symptoms of ill health. Measurements of lung function by the use of peak expiratory flow meters were done four times a day. In addition, every second week the participants were subjected t a full spirometric test. Samples of urine and blood were examined, and bacteriological test from the throat was performed at the beginning and at the end of the study. A comprehensive measurement program of outdoor air contaminants (including nitrogen oxides, sulphur dioxide) is presented. Estimation of each participant's exposure was performed hour by hour based on detailed modelling of the measured levels, known emissions of pollutants and meteorological conditions, as well as diary information on the participant's movements through the various micro-environments. The estimated exposures were generally low. In this presentation, a linear regression model and their corresponding parameter estimates were applied on an individual basis to evaluate any effect of air contamination on lung function.(ABSTRACT TRUNCATED AT 250 WORDS)
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7787815
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Trypanosoma cruzi binds to laminin in a carbohydrate-independent way.
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The binding of 125I-laminin to trypomastigotes is specific and 2-5 x 10(3) laminin-binding sites were calculated to be present on the surface of a live trypomastigote. Anti-laminin antibodies were able to inhibit the invasion of cultured cells by trypomastigotes (62-75%), suggesting that laminin may be involved in the adhesion of the parasite to host cells. By affinity chromatography, an 85-kDa glycoprotein was isolated (laminin-binding glycoprotein, LBG) from trypomastigote lysates, but not from epimastigote lysates. It is suggested that at least fragment E8 (but not E1') from laminin could be involved in the reaction which is independent of the carbohydrate moieties from both ligand and receptor. It is also shown that LBG is a member of the Tc-85 family, previously shown to be related to the invasion process of the parasite.
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7787814
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Characterization of glycoprotein gp43, the major laminin-binding protein of Paracoccidioides brasiliensis.
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We have demonstrated that laminin mediates the adhesion of P. brasiliensis to monolayers of epithelial cells through specific binding to the surface glycoprotein gp43. This binding seems to be related to the fungal pathogenesis. We now report the confirmation of these findings by scanning electron microscopy and show that some isolates that do not secrete gp43 do express the protein as seen by studying whole cell extracts. These results confirm the ability of these strains to produce paracoccidioidomycosis but should not be used for serological purposes since the absence of gp43 in exoantigens may lead to false negative results.
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7787813
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Fibrosis patterns of lesions developed by athymic and euthymic mice infected with Paracoccidioides brasiliensis.
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Athymic and euthymic mice with BALB/c background were used to study the patterns of fibrosis during ip infection with a virulent isolate of Paracoccidioides brasiliensis. Specimens from various organs were collected from the animals at 1, 4 and 7 weeks after infection and observed under light microscopy using various histologic staining methods. Lesions from the first week of infection, in both animal groups, presented a predominance of collagen III over I, carboxylated proteoglycans, and a tendency to encapsulation. From 4 weeks onward, the lesions of nu/+ mice tended to involute to macrophage-pseudoxanthomatous aggregates or to encapsulation with an increase of collagen I and sulfated proteoglycans. On the contrary, with the evolution of the infection, the nu/nu mice displayed permanently active lesions, rich in reticular fibers and carboxylated proteoglycans, with varied amounts of collagens III and I, without or with minimal encapsulation. However, independent of the type of mice, or of the type of lesions, the minimal P. brasiliensis-ECM unit was formed by a fibrillar cocoon of reticular fibers that encloses an individual yeast or a "family" composed of a mother cell plus one or various peripheral daughter cells, alone or engulfed by macrophages or giant cells. The overall difference of the lesions of nude and normal mice was not in isolated aspects of their components, but in the general architecture of the lesions. Those of nu/+ mice were either of involutive or of encapsulated type (slightly active), and those of nu/nu mice were of the sustained-expansive type (very active), without or with minimal encapsulation.
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7787810
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Integrin receptors and TGF-beta expression in chronic myeloid leukemia cells.
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To understand the relationship between transforming growth factor beta-1 (TGF-beta 1) and the integrin profile presented by chronic myeloid leukemia cells, we have studied, using Northern analysis, the expression of TGF-beta 1 messenger RNA (TGF-beta mRNA) in myeloid cell lines and in patients with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). In addition we determined the positivity for alpha 4 and alpha 5 integrin molecules in those cells using specific monoclonal antibodies and flow cytometry. CML patients (N = 3) presented mean values of alpha 4 and alpha 5 higher (alpha 4: 60 +/- 20%; alpha 5: 70 +/- 41%) than AML (N = 10) blast cells (alpha 4: 25 +/- 23%; alpha 5: 18 +/- 16%). Northern analysis revealed an almost four-fold higher expression of TGF-beta mRNA in K562 (derived from a patient with chronic myeloid leukemia) compared to the myeloblastic cell line HL60. The highest TGF-beta mRNA levels were seen in the U937 lineage. CML leukemic cells (N = 3) showed high TGF-beta mRNA levels comparable to the levels expressed by K562 which was paralleled by high beta 1 integrin mRNA. AML blast cells presented a variable degree of expression of TGF-beta mRNA when compared to HL60. One patient with acute megakaryoblastic leukemia (FAB subtype M7), usually associated with myelofibrosis, presented the highest TGF-beta mRNA levels. We conclude that studying TGF-beta 1 and its mechanisms of action will help in understanding fibrosis in leukemic patients, and perhaps to design treatments for such conditions.
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7787812
|
Proteoglycans and glycosaminoglycans synthesized by the hepatic granulomas isolated from schistosome-infected mice and by a granuloma-derived connective tissue cell line.
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1. This paper summarizes our studies on proteoglycans and glycosaminoglycans in the hepatic fibrosis occurring in schistosomiasis. 2. We have compared proteoglycans and glycosaminoglycans isolated from schistosomal fibrotic granulomas with those obtained from the cellular and extracellular compartments of a murine cell line derived from schistosome-induced granulomas, the primary cell line "GR". 3. Our results have shown some biochemical and structural similarities between proteoglycans and glycosaminoglycans extracted from granulomas and those synthesized and secreted by GR cells, suggesting that these cells may be the major cell population involved in synthesis and accumulation of these molecules in the schistosomal periovular granulomas in liver. Furthermore, we have shown that GR cells can function as an extramedullary myelopoietic stroma that mediates a long-term myeloid proliferation through an autocrine mechanism where the interaction between myelopoietic growth factors and cell-surface heparan sulfate proteoglycans was characterized.
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7787811
|
Extracellular matrix degradation in parasitic diseases.
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1. Fibrosis is an important manifestation of several parasitic diseases, but is not irreversible. A marked degree of extracellular matrix degradation can occur after cure of parasitism. Patients with the hepatosplenic form of schistosomiasis undergo considerable resorption of portal fibrosis months or years after curative treatment as demonstrated by ultrasonography and pathological examination. 2. Studies of the post-treatment degradation of extracellular matrix in schistosomal periovular granulomas have demonstrated two forms of collagen degradation: in hepatic granulomas formed during early infection a rapid process occurs, with the extracellular breakdown of fibers and internalization of collagen fragments, whereas during late infection, degradation is slow and is accompanied by focal electrondense and/or lytic changes. 3. Extensive extracellular matrix degradation and resorption occurring after curative treatment was recently described in the liver of a man with advanced visceral leishmaniasis and in the heart of mice with chronic Chagas' disease.
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7787809
|
Glycosaminoglycan structure and content differ according to the origins of human tumors.
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The glycosaminoglycans of the tumor mass and from the urine of patients with a nephroblastoma of embryonic origin (Wilms' tumor) and hypernephroma were analyzed. The urine of patients with Wilms' tumors prior to treatment, and two patients with metastasis contained high levels of hyaluronic acid (2-5 mg/l of urine) when compared to patients after surgery or chemotherapy where the content of hyaluronic acid was less than 0.1 mg/l. Urine of patients with hypernephroma and normal individuals contained even smaller amounts of hyaluronic acid. Normal kidneys contain mainly dermatan sulfate and heparan sulfate, while the hypernephroma and Wilms' tumor contain substantial amounts of chondroitin sulfate. The amount of glycosaminoglycans isolated from Wilms' tumor and hypernephroma were 10 times and 3 times, respectively, greater than normal kidneys. The amounts of hyaluronic acid in Wilms' tumor varied from 56 to 73% whereas normal kidneys contained about 13%. Chondroitin sulfate was also increased in Wilms' tumor and hypernephroma. It corresponded to 11% and 42%, respectively, of the total glycosaminoglycans. These and other findings indicate that the glycosaminoglycans of Wilms' tumors resemble those present during embryonic development of normal tissues whereas those in hypernephroma are typical of other carcinomas of different origins.
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7787808
|
Use of lectins to evaluate the effects of GaAs softlaser on dog tendon.
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1. Lectins labeled with colloidal gold particles were used for the ultrastructural evaluation of the biological effects of GaAs softlaser irradiation on the healing of dog tendon wounds. 2. Six dogs were submitted to tenotomy and tenorrhaphy on the right and left hind legs. All animals received laser irradiation (4 J/cm2) daily for ten days only on the left leg, and the right leg of the same animal was used as control. Biopsies were taken 11, 22 and 40 days after surgery. 3. Laser-irradiated and control tendon tissues were embedded in L.R. White resin and thin sections were incubated in the presence of gold-labeled Arachis hypogaea (PNA), Canavalia ensiformes (Con A) and Triticum vulgare (WGA). 4. In general, the control and laser-irradiated tissues presented homogeneous and similar labelling of heterochromatin, rough endoplasmic reticulum and extracellular matrix. 5. We conclude that GaAs softlaser irradiation does not produce significant changes in the glycosylation of healing tendons.
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7787806
|
Cell adhesion in muscle.
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1. Attachment to extracellular matrix is thought to be particularly important for striated muscle cells, since skeletal and heart muscle have to withstand considerably strong forces. 2. We have recently shown that a defect in a protein of the muscle basement membrane, M-laminin, is correlated with muscular dystrophy in human and mouse. The disease associated with defects in M-laminin is thus analogous to that caused by defects in the cytoskeletal protein, dystrophin, the Duchenne/Becker muscular dystrophy. 3. One may propose the hypothesis that a pathway of interacting proteins is required to connect the cytoskeleton of the muscle fiber to the extracellular matrix, and that a defect in any protein in this chain would result in severe impairment of muscle cell attachment with resulting muscle damage upon use of the muscle. The existence of such chains of proteins may be expected from known mutations in muscle proteins in Drosophila and Caenorhabditis elegans. Some of these mutations cause phenotypes resembling muscular dystrophy in mammals. 4. It will be important to identify all the proteins that are participants in muscle cell attachment, including receptors for M-laminin and proteins associated with these receptors.
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7787807
|
Altered deposition of extracellular matrix components in the skeletal muscle and lymph node of the MDX dystrophic mouse.
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1. MDX mice derived from a colony of C57BL/10ScSn mice develop an X-linked recessive muscular dystrophy, thus providing an adequate model to study the pathogenesis of muscular dystrophy. 2. Skeletal myofibers of MDX mutant mice were heterogeneous, with disorganization of myofilaments and the absence of immunolabelling for dystrophin with monoclonal antibody DY4/6D3. 3. Marked deposition of reticulin, collagenic fiber (types, I, IV) and laminin (LN) were consistently present mostly around lesioned and necrotic myofibers associated with an intense inflammatory reaction, whereas strong immunolabelling for TIII-C, TIV-C and FN was often associated with regenerated fibers. 4. During the onset (3 weeks of postnatal life) of disease and height of myonecrosis (5-6 weeks of postnatal life), popliteal lymph nodes showed dense argyrophilic meshwork, intense immunolabelling for collagens types I and IV, FN, LN and enlargement of the hili which were packed with mononuclear cells. Such alterations, albeit less intense, were still observed in MDX mice with 20 weeks of postnatal life. 5. The results support the view that ECM components might be influencing the migration of inflammatory cells and the process of myonecrosis in the skeletal muscle of MDX dystrophic mice.
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7787805
|
Biomatrix effect on Sertoli cells phospholipids.
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In order to investigate the influence of biomatrix on Sertoli cell morphology and on the phospholipids content, these cells were isolated from testes of 15-day old Wistar rats and plated onto plastic coated with extracellular matrix extracted from seminiferous tubules, here denoted biomatrix. When the Sertoli cells were cultured on biomatrix they did not form a monolayer until day 7 of culture, while cells plated onto plastic did so 48 h after plating. On day 5 of culture, Sertoli cells were incubated for 48 h with 5 microCi/ml 32P. There was no difference in 32P incorporation into lipids of cells plated onto biomatrix or plastic. However, there was a larger amount of phospholipid phosphate in cells plated onto biomatrix than onto plastic. When the phospholipids were analyzed by bidimensional thin-layer chromatography, no differences were detected in their distribution; however, there was a significant decrease in the percentage of sphingomyelin in cells plated onto biomatrix when compared to plastic. These results showed that the cells cultured on biomatrix change their phospholipids content, but not their distribution. The importance of a small reduction in sphingomyelin content remains to be investigated.
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7787804
|
Scanning electron microscopy of acinar cells of rat submandibular salivary glands.
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1. The submandibular salivary gland of rats was observed by high-resolution scanning electron microscopy employing the aldehyde-osmium-DMSO-osmium method. 2. The intracellular membranous components and sponge-like structures of basement membrane containing the fine collagen fibrils of acinar cells were clearly identified in three-dimensional images. The granular endoplasmic reticulum and Golgi apparatus showed the luminal surface. The mitochondria were small, ranging in diameter from 0.3 to 0.5 microns, and revealed their cristae. The secretory granules ranged in diameter from 0.3 to 1.4 microns. Ribosome granules were attached to the surfaces of cisterns, and measured 20 to 25 nm in diameter. 3. The contact areas between the acinar cells revealed numerous cytoplasmic protrusions. In the striated duct cells, the mitochondria were arranged vertically and surrounded by basal infoldings of the plasma membranes. At high magnification, the mitochondrial cristae were visualized in their three-dimensional characteristics.
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7787803
|
Binding of heparin and compound Y to endothelial cells stimulates the synthesis of an antithrombotic heparan sulfate proteoglycan.
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The mechanism by which heparin and antithrombotic agents, including a cyclic octaphenolsulfonic acid (compound Y), stimulate the synthesis of an antithrombotic heparan sulfate by endothelial cells in culture was investigated. Compound Y increases the amount of heparan sulfate from the cell surface and secreted to the medium by endothelial cells by three-fold. Binding experiments have shown saturation of the endothelial cell receptors at a concentration of 0.16 microM for heparin and 2.7 microM for compound Y. The kinetic binding constants (Ks) for compound Y and heparin were 1,333 nM and 42 nM, respectively. It was also shown that both compounds bind to the same receptors. The Scatchard plots indicated that 1,319 nmoles compound Y and 35 nmoles heparin bound per microgram cell protein, indicating that 40-fold more molecules of compound Y bound to the receptors when compared to heparin. No significant internalization of the compounds was observed.
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7787800
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Carbohydrate-binding proteins in cell-matrix interactions.
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1. Carbohydrate-dependent interactions have been more extensively studied during the last decade. Although the roles of carbohydrates in cellular functions are still poorly understood, the finding of carbohydrate-binding proteins in animal cells opened a great number of perspectives. 2. Animal lectins are associated with tumor progression, playing a key role in neoplastic cell interactions with endothelial cells and extracellular matrix glycoproteins such as laminin. 3. Here, we review the role of animal lectins in the migrating phenotype of neoplastic cells and normal cells such as T-lymphocytes.
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7787801
|
Adhesion to laminin is down-regulated upon retinoic acid-induced F9 cell differentiation: a role for alpha 6/beta 1 integrin.
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F9 mouse teratocarcinoma cells have a high capacity to adhere to laminin and we identified alpha 6/beta 1 integrin as the principal laminin-binding protein present in these cells. F9 cells differentiated into parietal endoderm when monolayer cultures were treated with retinoic acid and dibutyryl cyclic AMP. In this process a decreased adherence to laminin was observed due to a lower expression of alpha 6/beta 1 integrin on the cell surface.
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7787802
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Heparan sulfate proteoglycan and control of cell proliferation: enhanced synthesis induced by phorbol ester (PMA) during G(1)-phase.
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The effect of phorbol 12-myristate-13-acetate (PMA), a tumor-promoting phorbol ester, on the synthesis of proteoglycans of endothelial cells in culture was investigated. This phorbol activates protein kinase C (PKC) when added to cells in culture. PKC, in turn, modulates the activity of growth factors. Using [35S]-sulfate or [3H]-glucosamine to label the proteoglycans we have observed a 4-24-fold increase of the heparan sulfate (HS) synthesis in a dose-dependent manner (0-100 ng/ml). Chondroitin sulfate (CS) synthesis was not affected by PMA. The effect of PMA could be completely abolished by a calcium ionophore (A23187). By the use of synchronized cells and PMA pulses at different periods of the cell cycle, as well as [3H]-thymidine incorporation, we were able to show that the enhancement of heparan sulfate synthesis is most prominent during G1. Our data suggest that the release of HS to the medium could be one of the responses of the cell to a mitogenic stimulus.
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7787799
|
The kinetics of chondroitin 4-sulfate release from stimulated platelets and its relation to thromboxane A2 formation and granule secretion.
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1. In platelet rich plasma (PRP), chondroitin 4-sulfate release from platelets occurred after stimulation with ADP (5 microM), collagen (5-10 micrograms/ml), or adrenaline (10 microM). Release started within 60 s and maximum release (0.7-2.0 mg/l) was reached within 180 s. TXA2 formation and dense granule release reached a maximum within 90 s after stimulation. 2. Using washed platelets (1.5 x 10(8) cells/ml), the platelet responses were faster. Release of chondroitin 4-sulfate and TXA2 started within 20-30 s after thrombin addition (100 mU/ml). Maximum release was reached within 60 s in both cases. Dense granule release started in the first 5 s of stimulation (34.6 +/- 12.4%) reaching maximum secretion (74.4 +/- 8.7%) within 60 s. 3. Our results demonstrate that maximal chondroitin 4-sulfate release occurs after the dense granule release reaction in both PRP and washed platelets. This observation suggests that chondroitin 4-sulfate is unlikely to be stored in the dense granules but may be stored in the alpha-granules.
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7787798
|
Thrombospondin: relationship to protease and growth factor/cytokine activity.
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1. The finding in the last two years of different proteins presenting structural homology with platelet thrombospondin (TSP-1) has permitted to establish the existence of a set of related genes referred to as thrombospondin family. While much work remains to be done concerning the characterization of the newly described members of the family, careful studies carried out on TSP-1 have been implicating this high molecular weight molecule (420-450 kDa) in a variety of aspects of cellular physiology. 2. The present text discusses the implications of the matrix-bound and fluid TSP-1 forms for cell adhesion and protease activity generation. Their relationships with growth factors in matrices are also discussed.
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7787797
|
Myelopoietic competence of stroma composed of hepatic granuloma-derived connective tissue cells or skin fibroblasts.
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1. Connective tissue cells isolated from hepatic granulomas (GR cells), induced in mouse liver tissue by schistosomal infection, are able to sustain myelopoiesis, while other connective tissue cells such as skin fibroblasts (SF) are not. 2. We compared the ability of SF and GR cells to sustain in vitro proliferation of the FDC-P1 myeloid cell line, dependent upon IL-3 or GM-CSF. 3. Only the GR stroma sustained the proliferation of co-cultured FDC-P1 cells. RT-PCR analysis showed that both cell lines expressed the message for GM-CSF, but not for IL-3. We showed that GM-CSF was produced by, and remained bound to the cell layer through heparan sulfate; this growth factor could be released by high-salt treatment in a biologically active form from both cell types. The same activity could be restored to NaCl-treated GR cells, but not to SF, by incubation with recombinant murine GM-CSF. 4. These results indicate that the ability of connective tissue cells to sustain myelopoiesis depends directly upon the capacity of their heparan sulfate-bearing molecules to bind and present the GM-CSF to the target cells in a biologically active form. Alternatively, a yet unidentified set of cell layer-associated molecules may be required for the positive or negative control of the membrane-bound GM-CSF.
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7787796
|
Matrix in signal transduction and growth factor modulation.
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The extracellular matrix (ECM) is indispensable for the survival of multicellular organisms. It provides the adherent cells with crucial clues for migration, proliferation and differentiation. These clues are transmitted to the interior of the cell by ECM receptors like the integrins. Signaling by the ECM occurs by induction of assembly and disassembly of cytoskeletal structures or by modulation of classical signal transduction pathways such as activation of phosphatidylinositol-proteases, growth factors and cytokines that are specifically bound to its constituents and thereby stored, localized and modulated in terms of their biological activities. Finally, both the quantity and the quality of growth factor signaling appear to be dependent on the temporal and spatial activation of ECM receptors, supporting the requirement of a crosstalk between matrix and growth factor receptors.
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7787795
|
Detection of a small proteoglycan present in xiphoid cartilage regions submitted to different biomechanical forces.
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1. The effect of biomechanical forces on large proteoglycans and collagen of cartilage has deserved intensive study, enhancing the importance of these molecules to support a better distribution of compressive forces especially in articular cartilage. In the present study, other extracellular matrix components, non-collagenous proteins and small proteoglycans, have been evaluated in terms of biomechanical tension. 2. Different parts of chicken xiphoid cartilage, lateral (R and L) and central (C) portions, which bear different biomechanical tensions, were analyzed. DEAE-cellulose chromatography profiles were similar for R and L portions. SDS-PAGE analyses revealed proteins of 29, 60 and 70 kDa for R and L. The 20- and 70-kDa proteins were not detected in the C portion while the 60-kDa protein was present at a high level. 3. The differences found between lateral (R and L) and central portions of the xiphoid cartilage may be related to the structure of the cartilage which bears higher tension forces than the lateral parts.
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7787794
|
Proteoglycans in skeletal muscle.
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1. Proteoglycans are macromolecules composed of a protein and one or more chains of sulfated carbohydrates, the glycosaminoglycans. Proteoglycans are found on the cell surface and in the extracellular matrix participating in the cell-cell and cell-extracellular matrix interaction. In this review I present the information accumulated in the past years regarding the presence, characteristics, localization, control of expression and alteration in some pathological states of skeletal muscle proteoglycans. 2. This review presents and discusses current information in this area and some projections for the future in four sections: first, the proteoglycans present in embryonic cells and cell lines from skeletal muscle. Second, the presence of proteoglycans in adult skeletal muscles. Third, the regulation of the expression of skeletal muscle proteoglycans, and fourth, skeletal muscle proteoglycans in pathological conditions.
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7787793
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Sequencing of heparan sulfate proteoglycans: identification of variable and constant oligosaccharide regions in eight heparan sulfate proteoglycans of different origins.
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The sequence of the disaccharide units of eight heparan sulfate proteoglycans of different origins is described. All heparan sulfates contain 5 variable regions made of oligosaccharide blocks of disaccharides, namely, GlcUA(1-4)GlcNAc, GlcUA(1-4)GlcNS, IdoUA (1-4) GlcNS,6S,IdoUA-GlcNAc,6S, and IdoUA,2S(1-4)GlcNS,6S, besides two constant regions made of an internal tetrasaccharide (IdoUA-GlcNAc-IdoUA-GlcNS) and monosaccharides (GlcNS, and GlcNS,6S) at the non-reducing terminal. The N-acetylated region of the heparan sulfates is linked to the serine of the protein core through a trisaccharide of Xyl-Gal-Gal. Heparan sulfates differ from one another in terms of the number of disaccharides that compose each block.
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7787792
|
On the monophyletic evolution of the metazoa.
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1. The shift from unicellular life to multicellular, integrated organisms has been accompanied by the acquisition of adhesion proteins. Recently we succeeded in cloning some genes coding for such proteins from the lowest multicellular animals, the marine sponges (model: the siliceous sponge Geodia cydonium). 2. G. cydonium contains several lectins and cDNA for two of them (termed LECT-1 and LECT-2) was cloned. Both lectins have a framework sequence of 38 conserved amino acids which are characteristic for the carbohydrate-binding site of vertebrate S-type lectins. Next, we have isolated and characterized a cDNA coding for a receptor tyrosine kinase of class II (GCTK). The deduced amino acid sequence shows two characteristic domains: i) the tyrosine kinase domain and ii) an immunoglobulin-like domain. The latter part shows high homology to the vertebrate type immunoglobulin domain. This result, together with the lectin data, demonstrates that binding domains of such adhesion proteins are not recent achievements of higher animals but exist already in animals (sponges) which have diverged from other organisms about 800 million years ago. 3. Considering the fact that during embryogenesis of sponges a typical anteroposterior organization pattern is seen, a "homeotic" organ-like transformation has been postulated. The subsequent search for genes provided with the homeodomain sequence was successful. The deduced amino acid sequence of G. cydonium showed high homology to chicken and to the Antennapedia sequence from Drosophila melanogaster. 4. These data support the view that the kingdom Animalia is of monophyletic origin.
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7787781
|
Hematopoietic growth factors for the treatment of severe chronic neutropenia.
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Severe chronic neutropenia (SCN) is a rare but important cause of recurrent fevers, oropharyngeal ulcerations and severe infections. In three forms of SCN, i.e., congenital neutropenia (Kostmann's syndrome and related syndromes), idiopathic neutropenia (both childhood and adult), and cyclic neutropenia, it is now established that long-term treatment with the hematopoietic growth factor, recombinant human granulocyte colony stimulating factor (rHuG-CSF or Filgrastim), can elevate blood neutrophil counts to the normal range in most patients, with a concomitant reduction in infection-related events including fever, oral ulcerations, antibiotic use and symptoms of inflammation. Treatment with this growth factor causes an increase in the number and maturity of marrow cells of the neutrophilic series; other cell lines are largely unaffected. Marrow stimulation and expansion are reflected by the occurrence of bone pain early in therapy, as well as some increase in spleen size in most cases. Adverse effects of therapy are infrequent in both children and adults, and long-term treatment with daily or every-other-day s.c. injections of rHuG-CSF are well accepted. Because of the risk that some patients with chronic neutropenia may have or develop myelodysplasia and/or leukemia, careful pretreatment evaluations (blood, bone marrow and cytogenetics) and long-term observations are extremely important. An international registry for patients with SCN has been established to maintain records and further investigate these conditions.
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7787777
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Retention and multilineage expression of human hematopoietic stem cells in human-sheep chimeras.
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We have taken advantage of the permissive environment of the early gestational age fetus to engraft human hematopoietic stem cells (HSC) into preimmune fetal lambs. The resulting chimeras exhibit long-term multilineage engraftment of human cells in the bone marrow (BM) and peripheral blood (PB). Long-term multilineage reconstitution of second generation recipients by human cells isolated from chimeric sheep BM indicates that the engraftment in this model involved long-term repopulating human HSC. The model appears to be sensitive enough to detect relatively small numbers of transplanted HSC from pre- and postnatal human sources. Finally, transplantation of mature T lymphocyte-containing cells from a variety of sources results in lethal graft-versus-host disease (GVHD), analogous to clinical BM transplantation, suggesting that, at least in some respects, the model is biologically relevant. The human-sheep model is promising and may have important advantages over murine models for the in vivo study of normal and abnormal hematopoiesis and as a potential assay system for human HSC.
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7787779
|
Platelet glycoprotein IIb gene expression as a model of megakaryocyte-specific expression.
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Glycoprotein (GP)IIb/IIIa is an integrin complex normally restricted in its expression to platelets and the megakaryocytes from which they are derived. This complex functions as a receptor for fibrinogen and other ligands and is involved in platelet aggregation. The receptor complex is expressed at high levels during final megakaryocyte differentiation. Further, while GPIIIa is expressed in other tissues as part of the vitronectin receptor, GPIIb is only expressed on maturing megakaryocytes and the platelets derived from them. Thus studies of the GPIIb gene may serve as a model of gene regulation during this process. Over the past several years, the genes for both GPIIb and IIIa have been cloned and analyzed. The GPIIb gene contains 30 exons over 18 kilobases (kb). The transcriptional start site has been determined and there does not appear to be a TATA-box immediately upstream of this site. Studies have been done to define regulatory elements upstream of the transcriptional start site. Most of these studies focused on the human promoter and on studies using megakaryocytic cell lines. These studies have defined several important tissue-specific promoter elements including a GATA454 site (454 basepairs upstream of the transcriptional start site that involves a GATA-binding consensus sequence), a GATA54 site and an Ets35 site (that involves an Ets-binding consensus sequence). Expression studies with megakaryocytic cell lines suggest that each of these sites effects expression approximately threefold. Further, an Ets510 site was also described that had a similar effect. While these studies were underway, we pursued studies of the rat 5'-flanking region using a rat primary marrow expression system. Qualitatively, our data support the human data; however, quantitatively, we found significant differences from the human studies done in cell lines. We found that the major tissue-specific promoter element was the GATA454 site. Mutations altering this site result in an approximately fiftyfold drop in expression. In comparison, eliminating the Ets510 site by truncation or point mutation had only a twofold effect on expression. Mutations at the Ets35 site did effect expression at a high level, decreasing expression approximately fifteenfold, while mutations at the GATA54 site effected expression by approximately ninefold. In addition, using 50 bp deletions, we have preliminarily defined two domains from -450 to -351 bp and -150 to -101 bp upstream of the transcriptional start site that effected expression. The former appears to contain a positive regulatory element, while the latter appears to be a silencer element.(ABSTRACT TRUNCATED AT 400 WORDS)
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7787780
|
Unstable triplet repeat sequences: a source of cancer mutations?
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Numerous mutations have been related to various types of cancer. Short tandem repeats (STRs) are repetitive DNA elements that are often polymorphic in normal populations. Triplet repeat expansion has been related pathogenetically to six diseases: fragile X syndrome, fragile X E syndrome, spinobulbar muscular atrophy, myotonic dystrophy, Huntington's disease, and spinocerebellar ataxia type 1. The characteristics of the GC-rich repeat expansion are diverse and result in profound changes in phenotype, sometimes within a single generation in affected families. We expect that simple repeat expansion will cause some cancers based on our knowledge of these unstable DNA sequences in the previously mentioned genes. This may occur by alteration of tumor suppressor gene expression, alteration in coding features of proteins, or change in bystander oncogene expression such as that which occurs with DNA methylation. The demonstrated meiotic instability could link this mechanism of mutation of familial cancer syndromes. The recent discovery of STR instability at multiple sites in hereditary nonpolyposis colon cancer suggests sequence instability may be a factor in cancer progression. Continued identification of candidate genes containing triplet repeats should allow a ready testing of the hypothesis that unstable simple repeat sequences can cause cancer.
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7787778
|
rHuGM-CSF after high-dose chemotherapy in post-remission acute leukemia.
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Post-remission high-dose chemotherapy has been an important advance in the treatment of adult acute leukemia (AAL). Without the use of colony-stimulating factors (CSFs) in this program, the mortality rate varies from 5 to 17%, and infectious complications arise in more than 50%. These findings limit the widespread use of such forms of therapy. The use of high-dose ara-C (HIDAC) alone or in combination with other drugs is the most common regimen studied, however neither other drug combinations nor the addition of supporting CSFs have been extensively explored. For this reason we studied the effect of high-dose cyclosphosphamide-etoposide (CECY) plus recombinant human granulocyte-macrophage (rHuGM)-CSF with the intention of decreasing morbimortality and prolonging disease-free survival (DFS). Since 1992 we have included 51 complete remission patients with AAL in the CECY plus rHuGM-CSF protocol. The maximal myelosuppression occurred in a mean of 6.4 days, and the mean days required for absolute neutrophil count recovery was 13 days and for platelets 21 days (p < 0.0001). No toxic deaths occurred and only two serious infectious complications were seen. After two years of follow-up, 50% of de novo acute myelogenous leukemia patients had relapsed at 13 months, and 50% of de novo adult acute lymphocytic leukemia patients had relapsed at 15 months. In a recent update, we have not seen a significant difference when compared to historic groups. The CECY protocol does not appear to be superior in prolonging DFS compared to HIDAC as a post-remission strategy for newly diagnosed AAL. The main difference was the absence of toxic deaths and minimal serious infectious complications in the CECY protocol. Therefore, we suggest that the use of rHuGM-CSF in post-remission programs should be included in future studies.
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7787775
|
Multiple neurotrophic factors including NGF-like activity in nerve regeneration chamber fluids.
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Silicone nerve regeneration chambers were implanted between the cut ends of the sciatic nerve of adult rats. Neurotrophic activities in cell-free fluids collected from the chambers were determined using bioassays for survival of embryonic chick ciliary and sympathetic neurons in culture. Separation by molecular exclusion HPLC of the components of fluids collected 1, 2 or 3 days after implantation revealed the presence of a multitude of neurotrophic factors differing in their molecular weights, specificity towards the two types of neurons, and time course. Antiserum to nerve growth factor partially blocked sympathetic activity of fluids collected at 1 day. Affinity purified antibody was also effective and completely eliminated bioactivity of HPLC fractions corresponding to the molecular weight of nerve growth factor. The presence in the fluids of 13-18 and 20-32 kD components active towards ciliary neurons is consistent with the release of fibroblast growth factor and ciliary neurotrophic factor respectively. The stimulation of sympathetic neurons by the 13-18 kD material, and also by 4-6 and 7-11 kD components cannot be entirely accounted for by known factors. This study demonstrates that a number of neurotrophic factors, which differ in their specificity towards sympathetic and parasympathetic neurons, are made available to the region of axonal regrowth over the first few days of regeneration. Contrary to earlier reports, nerve growth factor-like activity was shown to be present in nerve regeneration chambers.
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7787776
|
Thiamine homeostasis in neuroblastoma cells.
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We recently showed that thiamine uptake by neuroblastoma cells is mediated by two saturable transport system: the first with high affinity for thiamine (Km = 35 nM) is blocked by veratridine; the other, with low affinity is blocked by Ca2+. The driving force for thiamine uptake is its phosphorylation to thiamine diphosphate (TDP) by thiamine pyrophosphokinase and subsequent binding of this cofactor to apoenzymes. Our results suggest that cells of neuronal origin possess mechanisms regulating the intracellular concentration of thiamine. At low external thiamine, the vitamin is taken up by a high-affinity transporter and pyrophosphorylated in thiamine diphosphate (TDP): this is the TDP pool of slow turnover. An intraover extracellular concentration gradient of free thiamine is observed at low external concentration of the vitamin. At higher external thiamine concentration, TDP accumulation is limited by the binding capacity to the apoenzymes and unbound TDP (i.e. a small pool of fast turnover) is quickly hydrolyzed. Thiamine is slowly released by the cells by at least two different mechanisms. The first, accounting for a maximum of 50% of total thiamine release, is stimulated by external thiamine and is blocked by veratridine, suggesting that it is a self-exchange mechanism catalyzed by the high affinity thiamine transporter. The remaining thiamine efflux is neither sensitive to veratridine nor to Ca2+ and its mechanism is unknown. About 25% of intracellular thiamine is not released, even after treatment of the cells with digitonin, thus maintaining an apparent gradient. This suggests a binding or sequestration in intracellular compartments.(ABSTRACT TRUNCATED AT 250 WORDS)
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7787774
|
Ascorbate/Fe(3+)-induced peroxidation and inhibition of the binding of A1 adenosine receptor ligands in rat brain membranes.
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The effect of peroxidation induced by the ascorbate/Fe3+ system on the binding properties of the A1 adenosine receptor, was studied in rat brain membranes, using the agonist, [3H]R-N6-phenylisopropyladenosine ([3H]R-PIA), and the antagonist, [3H]1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX). For the agonist, as well as for the antagonist, the number of binding sites (Bmax) was significantly (P < 0.05) reduced after pretreatment of the membranes with ascorbate/Fe3+. The affinity of the agonist for the binding sites was not statistically modified (P > 0.05) after ascorbate/Fe3+ pretreatment, whereas the Kd value of the antagonist was increased (P < 0.05) by a factor of 2. Ascorbate/Fe3+ pretreatment affected agonist binding in the presence of GTP in a similar way as that observed in the absence of GTP, suggesting that peroxidation also affects agonist binding to A1 adenosine receptors uncoupled to G-proteins. The results suggest that when brain membranes suffer free radical oxidative damage, the adenosine modulation of neuronal activity through A1 receptors could be less efficient.
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7787773
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The effect of insulin and insulin-like growth factor-1 on the expression of calretinin and calbindin D-28k in rat embryonic neurons in culture.
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In a primary culture of rat embryonic neurons, insulin (5 mg/ml) promoted neurite formation between neuron clusters in serum/glial-free simplified medium with a high concentration of transferrin (100 micrograms/ml). Insulin growth factor-1 (IGF-1) exerted a similar effect in the same culture system at a lower dose (100 ng/ml) of insulin. Calretinin has recently been identified as a calcium binding protein expressed predominantly in sensory neurons, which has six calcium binding domains and shows molecular similarity to calbindin D-28k, an intestinal calcium transporter protein also found in the CNS. The effects of insulin and IGF-1 on the expression of calretinin and calbindin D-28k were investigated in rat embryonic neuronal cell culture. When cells were cultured for 2 days, insulin and IGF-1 promoted the expression of both proteins; when cultured for more than 2 days, IGF-1 still exerted a growth factor effect, but insulin decreased the expression of calretinin. Using the present culture system, we demonstrated that the effects of closely related molecules, insulin and IGF-1 which share receptors reciprocally, differed in calretinin and calbindin D-28k expression. Therefore, these two calcium binding proteins may play different physiological roles in the nervous system based either on different molecular mechanisms or switching roles at different stages of CNS development. Amplification based on Western blot employing the streptoavidin-horseradish peroxidase method was applied to detect calretinin and calbindin D-28k in the culture system by an immunoblotting technique.
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7787772
|
Increased axonal regrowth of lesioned rat sciatic nerve by veratrylguanidine methane sulfonate.
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Neurotrophic factors appear as essential factors for normal development and repair of the nervous tissue. Veratrylguanidine methane sulfonate, has been shown to induce important neurite outgrowth of cultured dorsal root ganglia isolated from newborn rats. Its action was similar to that of NGF and was found to be additive to that of NGF. In order to see if this compound was able to stimulate axonal growth in adult animals, we examined the effect of this substance on the regeneration of the lesioned sciatic nerve. Using histochemical, immunohistochemical and ultrastructural studies, it is shown that a single intraperitoneal injection of veratrylguanidine methane sulfonate significantly increases the axonal growth during repair of the adult rat sciatic nerve. The efficiency of this substance is explained by its good targeting and long life time in the sciatic nerve.
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7787771
|
Single cell RT-PCR proceeds without the risk of genomic DNA amplification.
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We have previously described a method for detection of mRNAs expressed in single cells after patch-clamp recordings. The method, termed single cell RT-PCR, involves aspiration of the cell content, a reverse transcription (RT) step, and a polymerase chain reaction (PCR) using specific primers. Since the nucleus is frequently harvested together with the cytosol, genomic DNA may generate false positive results. Thus, we demonstrated that dilutions containing a few copies of plasmid could be detected by PCR in a range which, according to the Poisson law, suggests that the PCR method can amplify from the two genomic alleles. We performed single cell RT-PCR of intronless GluR2 or GluR5 fragments by comparing cerebellar cell types where these mRNAs are known to be present or absent. For each cell the nucleus was harvested together with the cytosol. Following RT-PCR with GluR5 primers, all Purkinje cells (n = 6) yielded the expected PCR product, whereas it was not generated from any of the granule cells (n = 5). In corresponding experiments with GluR2 primers, we obtained the GluR2 product from all Purkinje cells (n = 5), but not from any of the glial cells (n = 5). These results are in agreement with the known cellular expression of GluR2 and GluR5 mRNAs. We conclude that the single cell RT-PCR method does not amplify the genomic DNA when the nucleus is aspirated together with the cytosol. We suggest that genomic DNA amplification is avoided, because the genomic alleles are not exposed during the procedure.
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7787770
|
Inhibitory effects of lithium ion on intracellular Ca2+ mobilization in the rat hippocampal slices.
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Lithium is well established as a treatment of manic-depressive illness. As for the mechanism of action of lithium, it is proposed that lithium has effects on intracellular calcium ion (Ca2+) movement. But there are few reports in which the effects of lithium on intracellular Ca2+ movement are observed in the mammalian brain. We therefore examined the effects of lithium on intracellular Ca2+ changes in the rat hippocampal slices with a Ca2+ sensitive dye fura-2, and analyzed by means of a fluorescence microscope, a video-camera and photometrical devices. From the results of treatment with various noradrenergic agonists or antagonists, noradrenaline (NA)-induced intracellular Ca2+ change appears to be mainly mediated by alpha 1-adrenoceptors (AR) rather than alpha 2- or beta-AR. Furthermore, they are considered to be mediated by both alpha 1A-AR and alpha 1B-AR, and to be partly dependent on extracellular Ca2+. Lithium decreased NA-induced intracellular Ca2+ mobilization by attenuation of T1/2 rather than a change in the peak value, and antagonized ouabain-induced intracellular Ca2+ increase. Lithium may therefore suppress intracellular Ca2+ movement by enhancing the extrusion of intracellular Ca2+.
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7787769
|
Differential characteristics and regulation of arylamine and arylalkylamine N-acetyltransferases in the frog retina (Rana perezi).
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Arylamine N-acetyltransferase activity (A-NAT: E.C.2.3.1.5) from Rana perezi retina was studied using p-phenetidine as specific substrate. Enzyme characteristics and regulation were compared with respect to the arylalkylamine N-acetyltransferase (AA-NAT: E.C.2.3.1.87) from the same tissue. A-NAT activity is distributed in both neural retina and choroid-pigmented epithelium complex, showing a 10-fold higher specific activity in neural retina. In contrast, AA-NAT activity is restricted to neural retina. Subcellular localization in neural retina indicated that both enzymatic activities are in the supernatant fraction (39,000 g, 20 min). p-Phenetidine acetylation was linear as a function of the neural retina amount in the assay (1/16 to 1 retina), and it is insensitive to phosphate buffer pH in the range 6.5-8.4. A-NAT kinetic showed a hyperbolic shape for both cosubstrates. Kinetic constants were KM = 11.2 microM, Vmax = 0.49 nmol/h/mg prot. for p-phenetidine (50 microM acetyl-CoA), and KM = 113.4 microM, Vmax = 3.1 nmol/h/mg prot. for acetyl-CoA (5 mM p-phenetidine). The additivity test for both enzymatic activities in retina homogenates demonstrated that both acceptor amines do not compete for the catalytic sites. Serotonin addition in the assay modifies differentially the kinetic characteristics of both enzymes. Serotonin acted as a strong mixed inhibitor, mainly competitive in nature (competitive Ki = 18.1 microM; non-competitive Ki = 1.9 mM) for AA-NAT. However, it acted as a weak inhibitor with respect to A-NAT, mainly non-competitive, (competitive Ki = 5.7 mM; non-competitive Ki = 8.7 mM).(ABSTRACT TRUNCATED AT 250 WORDS)
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7787767
|
Dephosphorylation of abnormal sites of tau factor by protein phosphatases and its implication for Alzheimer's disease.
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The abnormally phosphorylated forms of tau factor are major constituents of neurofibrillary tangles in Alzheimer's disease brain. In order to investigate protein phosphatases which are related to dephosphorylation of abnormal phosphorylation sites, we examined the dephosphorylation of tau factor phosphorylated by three proline-directed type protein kinases. Tau factor phosphorylated by cdc2 kinase and tau protein kinase II was dephosphorylated by the holoenzyme of protein phosphatase 2A and calcineurin, while either the catalytic subunit of protein phosphatase 2A or protein phosphatase 2C could not catalyze the dephosphorylation. From the kinetic analysis, we concluded that tau factors phosphorylated by the protein kinases serve as good substrates for protein phosphatase 2A and calcineurin. On the other hand, tau factor phosphorylated by glycogen synthase kinase 3 alpha was dephosphorylated by the catalytic subunit of protein phosphatases 2A as well as the holoenzyme of protein phosphatase 2A and calcineurin. It has been reported that serines 199, 202 and 396 according to the numbering of the longest human tau isoform are among the major abnormal phosphorylation sites of tau factor. We synthesized two phosphopeptides which contained phosphoserines 199 and 202 or phosphoserine 396 and prepared the polyclonal antibodies specific for the phosphopeptides. Using these antibodies, we confirmed that the holoenzyme of protein phosphatase 2A and calcineurin could dephosphorylate phosphoserines 199, 202 and 396 in tau factor. The catalytic subunit of protein phosphatase 2A could dephosphorylate phosphoserine 396 but not phosphoserines 199 and 202. Neurofibrillary tangles in Alzheimer's disease brain were immunostained with both antibodies but the normal neurons in the normal aged brains were not. The results suggest that protein phosphatase 2A and calcineurin can be involved in the dephosphorylation of abnormal phosphorylation sites in tau factor and that the dephosphorylation of phosphoserine 396 is differently regulated from phosphoserines 199 and 202.
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7787768
|
Glutamatergic receptor kinetics are not altered by perinatal exposure to aspartame.
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Observation of reduced levels of glutamic acid and aspartic acid in brain of weanling rats exposed perinatally to aspartame prompted a study of the effect of this food additive on glutamatergic receptor kinetics. Aspartame 500 mg/kg/day in drinking water was administered to Sprague-Dawley rats throughout gestation and lactation. Brain was excised from weanlings 20-22 days old, and kinetics of the N-methyl-D-aspartate receptor and total glutamatergic binding in cerebral cortex and hippocampus were found to be unaffected by perinatal exposure to high levels of aspartame. Glutamic acid was decreased in both brain regions studied, and aspartic acid was decreased in hippocampus following perinatal aspartame exposure. These changes were reversible when aspartame administration was terminated. It is concluded that perinatal exposure to high doses of aspartame does not alter glutamatergic neurotransmission in cerebral cortex or hippocampus from weanling rats.
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7787766
|
Rapid and gentle extraction, reconstitution and characterization of microfilament and glia filament from rat astrocytes.
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We developed gentle and rapid methods for depolymerization and extraction of both microfilament and glia filament separately from a crude cytoskeletal fraction of rat astrocytes. Electron microscopy revealed that the filament reconstituted from the microfilament extract closely resembled F-actin that was formed from G-actin of rabbit skeletal muscle. It was found by immunoblotting analysis that even the reconstituted microfilament-like filaments, which had been purified by affinity chromatography with heavy meromyosin subfragment 1 (S1)-conjugated Sepharose, contained vimentin and glia fibrillary acidic protein (GFAP) besides actin, inferring the interaction between microfilament and glia filament. The filaments (9-10 nm thick) reconstituted from the glia filament extract were composed of actin and other minor components in addition to vimentin and GFAP. Actin, GFAP, 101, 34, 32.5, 30.5, 29.5 and 28 kDa proteins found in the reconstituted glia filament-like filaments were suggested to be glia filament-associated proteins.
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7787765
|
Methamphetamine-induced nuclear c-Fos in rat brain regions.
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To explore the possible robust changes in neuronal activity in dopamine-poor brain regions after an indirect dopamine agonist, methamphetamine, we have investigated its effects on c-fos expression in rat brain using immunocytochemistry of c-Fos. Intraperitoneal injection of methamphetamine (1.6-4.8 mg/kg), but not of saline, induced a widespread nuclear c-Fos-like immunoreactivity in the pyriform cortex and olfactory tubercle with greatest density followed by the II-VI layers of the neocortex, amygdala, hypothalamus, thalamus, nucleus accumbens and striatum. These expression patterns resemble those elicited by amphetamine and suggest that not only the dopamine-rich subcortical regions but also the cerebral cortex may play a crucial role in behavioral abnormality induced by methamphetamine.
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7787764
|
Interaction of rat brain phosphofructokinase with Alzheimer's beta A4-amyloid.
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One of the key functional disturbances in incipient dementia of Alzheimer type is the reduction of cerebral glucose utilization. Morphologically the brains of Alzheimer patients are characterized by multiple depositions of beta A4-amyloid mainly within extracellular senile plaques and in the walls of cerebral blood vessels, but also attached to intracellular neurofibrillary tangles. Intracellular beta A4-amyloid may bind to other cellular components. The interaction of beta A4-amyloid with phosphofructokinase, one of the key enzymes in glycolysis, was studied in vitro under various conditions. beta A4-amyloid was found to bind in nanomolar concentrations to phosphofructokinase and decrease its activity. Binding was demonstrated by enzyme linked immunoassays and by gel filtration studies. Inactivation of phosphofructokinase by beta A4-amyloid could only partially be prevented by fructose 6-phosphate. In control experiments no interaction was detectable between lactate dehydrogenase and beta A4-amyloid.
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7787763
|
Inhibitory effects of antidepressants on NMDA-induced currents in Xenopus oocytes injected with rat brain RNA.
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Although it has been reported that desipramine affects ion-channel activity of NMDA receptor/ion-channel complexes, the binding sites remain unclear. To identify the binding site, influences of desipramine on NMDA-induced current were examined in Xenopus oocytes injected with rat brain RNA and compared with those of blockers, MK-801, Zn2+ and Mg2+. Application of 100 microM desipramine irreversibly inhibited NMDA-induced inward current as well as 1 microM MK-801. Mg2+ and Zn2+ showed a reversible inhibition. Pretreatment with Mg2+ or Zn2+ abolished the irreversible inhibition of desipramine. In contrast, the irreversible inhibition of desipramine was still observed after application of Mg2+ and Zn2+. These results suggest that Mg2+/Zn2+ and desipramine bind on different sites from each other and affect the cation permeability via different mechanisms. Regarding inhibitory effects of other antidepressant drugs, imipramine and setiptiline were found to markedly inhibit NMDA current, while maprotiline, amitriptyline and lofepramine slightly inhibited the current. Mianserin, a potent antagonist of 5-HT1c receptors, however, had no influence.
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7787762
|
Novel halogenated analogs of tomoxetine that are potent and selective inhibitors of norepinephrine uptake in brain.
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Halogenated analogs of the potent norepinephrine (NE) uptake inhibitor, tomoxetine, were synthesized and their affinities for the serotonin (5HT) and NE uptake sites evaluated. One of the most potent was the 2-iodo substituted analog (289306) that inhibited [3H]tomoxetine binding to rat cerebral cortex with a Ki of 0.37 nM. The compound also inhibited the uptake of [3H]NE into rat hypothalamic synaptosomes with a Ki of 3.5 nM. This analog was significantly less potent at the 5HT uptake site, as exhibited by a Ki of 25 nM in the inhibition of [3H]paroxetine binding and a Ki of 121 nM in [3H]5HT uptake. The resolved (R) enantiomer (303926) was 10 times more potent as a [3H]NE uptake inhibitor and 29 times more potent as an inhibitor of [3H]tomoxetine binding than the (S) enantiomer (303884). Administration of 289306 to rats prior to an i.c.v. injection of 6-hydroxydopamine prevented the depletion of hypothalamic NE and Epi with ED50 values of 0.28 and 0.47 mg/kg, respectively. Thus, 289306 was a potent inhibitor of NE uptake in vitro and in vivo. In addition, these compounds provide structures for potential ligands for the study of NE uptake sites by autoradiography, PET or SPECT imaging.
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7787761
|
Interaction between [3H]flunitrazepam and [3H]GABA binding in the cerebellum of reeler mice.
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It has been shown that in the cerebellum of reeler mutant mice GABA levels and GABA uptake increase while GABA binding decreases. This study shows that in the cerebellum of these mutants there is also an increase of benzodiazepine receptors. This increase is observed in cerebellar homogenates, in nuclei and in membranes. The increase in the density of central (i.e. clonazepam displacable) benzodiazepine receptors is primarily reflected in binding sites located in the GABA-receptor complex. In comparison to wild-type, GABA-modulin extracted from reeler cerebellum inhibits with a greater potency [3H]GABA binding. The increase in the central-type of benzodiazepine binding and its interaction with GABA binding, observed in cerebellar membranes, is interpreted as a functional response to the decrease in GABA binding and may reflect benzodiazepine receptor condensation and/or changes of subunit composition of the GABA/benzodiazepine receptor complex. The enhanced activity of reeler GABA-modulin reflects a functional response to the increased GABA levels in reeler cerebellum. The increase of the peripheral-type (i.e. PK 11195 displacable) of benzodiazepine receptors is probably due to metabolic changes that may accompany reeler cerebellar mutation. Differences in nuclear benzodiazepine binding between reeler and wild-type mice add a physiological importance to the nuclear binding of this drug.
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7787758
|
Anaplastic myeloma.
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Anaplastic myeloma (AM) represents a rare variety of multiple myeloma (MM) with poor prognosis. One case with special interest is reported, which presented with manifestations due to the extramedullary localization and arose in the absence of an initial diagnosis of MM. In addition, differential diagnosis was based on morphological and immunocytochemical findings while treatment with radio-chemotherapy had no effect on the extramedullary sites.
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7787759
|
Kinins and kinin receptors in the nervous system.
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Kinins, including bradykinin and kallidin, are peptides that are produced and act at the site of tissue injury or inflammation. They induce a variety of effects via the activation of specific B1 or B2 receptors that are coupled to a number of biochemical transduction mechanisms. In the periphery the actions of kinins include vasodilatation, increased vascular permeability and the stimulation of immune cells and peptide-containing sensory neurones to induce pain and a number of neuropeptide-induced reflexes. Mechanisms for kinin synthesis are also present in the CNS where kinins are likely to initiate a similar cascade of events, including an increase in blood flow and plasma leakage. Kinins are potent stimulators of neural and neuroglial tissues to induce the synthesis and release of other pro-inflammatory mediators such as prostanoids and cytotoxins (cytokines, free radicals, nitric oxide). These events lead to neural tissue damage as well as long lasting disturbances in blood-brain barrier function. Animal models for CNS trauma and ischaemia show that increases in kinin activity can be reversed either by kinin receptor antagonists or by the inhibition of kinin production. A number of other central actions have been attributed to kinins including an effect on pain signalling, both within the brain (which may be related to vascular headache) and within the spinal dorsal horn where primary afferent nociceptors can be stimulated. Kinins also appear to play a role in cardiovascular regulation especially during chronic spontaneous hypertension. Presently, however, direct evidence is lacking for the release of kinins in pathophysiological conditions of the CNS and it is not known whether spinal or central neurones, other than afferent nerve terminals, are sensitive to kinins. A more detailed examination of the effects of kinins and their central pharmacology is necessary. It is also important to determine whether the inhibition of kinin activity will alleviate CNS inflammation and whether kinin receptor antagonists are useful in pathological conditions of the CNS.
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7787760
|
Receptors on astrocytes--what possible functions?
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Receptors for transmitters, as varied as those expressed by neurons, have been described on primary astrocyte cultures prepared from new-born rats and mice. A variety of functional effects and considerable cell-to-cell and regional heterogeneity have been observed for such receptors in vitro. The various systems available for studying the presence and properties of receptors on astrocytes in situ, and the results from these studies, are discussed. Much fewer studies using these more difficult systems have been done. So far, some resemblances and differences between in situ and in vitro work have been observed. More of these in situ studies, to supplement the ongoing in vitro work, are needed to enable us to determine unequivocally which receptors are present on astrocytes, and their functions in vivo. If there is cell-to-cell and CNS regional heterogeneity in vivo comparable to that seen in vitro, these analyses will be very complex. To illustrate the importance and variety of receptor-linked functions, a number of suggestions are made in this commentary, based on current proposals for the roles of astrocytes. However, it is argued that we need to have a more complete understanding of astrocyte functions in vivo, before we can really understand the functional significance of astrocyte receptors.
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7787757
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Acute myeloblastic leukemia associated with an intermediate state between the healthy carrier state and adult T-cell leukemia.
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This report describes an intermediate state between the human T-cell lymphotropic virus type I (HTLV-I) healthy carrier and adult T-cell Leukemia (ATL) who developed acute myeloblastic leukemia (AML, FAB subtype M2). The polyclonal integration of HTLV-I proviral DNA was demonstrated in the peripheral blood lymphoid cells, whereas AML cells had no HTLV-I proviral DNA. The patient achieved remission after combination chemotherapy but cells with lobulated nuclei persist at a low level and the polyclonal integration of HTLV-I proviral DNA is still demonstrated. We suggest that the patients with the integration of HTLV-I proviral DNA might develop secondary neoplasms more frequently than healthy carriers and this case stresses the need to exercise caution with these patients. The relationship between HTLV-I and AML is briefly discussed.
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7787756
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Establishment and characterization of a new Ph1-positive chronic myeloid leukemia cell line MC3 with trilineage phenotype and an altered p53 gene.
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A new Ph1-positive leukemic cell line (MC3) expressing the P210bcr/abl oncoprotein was established from a patient with CML in blast crisis. The MC3 cells showed the trilineage phenotype of myeloid, lymphoid (CD19) and megakaryocytoid lineages, and had a proliferative response to rhIL-1 and rhIL-3 in the serum-free culture. These results and the expression of CD34 indicated that the MC3 cells have characteristics of hematopoietic progenitor cells. Recently, it has been documented that alterations of the p53 gene in leukemic cells are frequently detected during the blast crisis of CML. The MC3 cells contained the altered p53 gene. In addition, the original leukemic cells showed the point-mutational activation of the N-ras gene and an additional chromosomal abnormality inv(3q), but the MC3 cells contained no such abnormalities, indicating that not all of the original leukemic cells had these abnormalities. Thus, the MC3 cell line may provide several insights into investigations of the blast crisis in CML as well as hematopoietic progenitor cells.
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7787755
|
Cutaneous lymphocytic vasculopathy in lymphoproliferative disorders--a paraneoplastic lymphocytic vasculitis of the skin.
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In this report the histopathology and the natural history of cutaneous lymphocytic vasculopathy (lymphocytic vasculitis) in patients with lymphoproliferative diseases, is described. Between January 1986 and June 1992, 116 patients with non-Hodgkin lymphomas (NHL) and chronic lymphocytic leukemias (CLL) were followed. Among them 3 patients with NHL, one with angioimmunoblastic lymphadenopathy/lymphoma and 7 with CLL developed cutaneous vasculitic changes during the course of their disease (incidence of 9.5%). All patients had advanced stage disease. Lymphomas were of B-cell origin and either low or intermediate grade. The median time between the diagnosis of NHL or CLL and the appearance of skin manifestations was 18 months. Recurrent vasculitic changes involving exclusively the skin, was characterized by a (maculo)papular rash, most commonly found in the upper and lower extremities. Pruritus of varying intensity was present in 82% of the patients. In the biopsy, all had perivascular and/or vessel wall lymphocytic infiltration of the dermis with occasional red cell extravasation. Immunohistochemical staining revealed that these infiltrates were mainly composed of T-lymphocytes. We conclude, that cutaneous lymphocytic vasculopathy is a relatively common paraneoplastic skin manifestation in patients with lymphoproliferative diseases and histologically is characterized as lymphocytic vasculitis with (peri)vascular infiltration by non-malignant T lymphocytes.
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7787753
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Treatment of newly diagnosed acute promyelocytic leukemia (APL) by all transretinoic acid (ATRA) combined with chemotherapy: The European experience. European APL Group.
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All transretinoic acid (ATRA) gives complete remission (CR) rates of 80 to 90% in newly diagnosed acute promyelocytic leukemia (APL). However, it has two major drawbacks (1) a rapid rise in WBC in some patients, with potentially fatal ATRA syndrome (2) rapid relapse with maintenance therapy using ATRA alone or low dose chemotherapy. The French APL group therefore designed a treatment approach with ATRA followed by intensive chemotherapy. The latter was administered after CR achievement with ATRA, or was rapidly added to ATRA in case of rapid rise in leukocyte counts. This combined approach, in a pilot study and in a randomized trial, proved superior to intensive chemotherapy alone, by slightly increasing the CR rate but more importantly by reducing the relapse rate. These results were confirmed by the Chinese, Japanese and New York groups. Our group (and other European groups) are now testing in a new randomized trial the better timing of ATRA and chemotherapy administration (ATRA followed by chemotherapy or ATRA plus chemotherapy) and the role (after an intensive consolidation) of maintenance treatment with intermittent ATRA, continuous low dose chemotherapy or both.
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7787754
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Treatment of acute promyelocytic leukemia in patients presenting at Vancouver General Hospital from 1983 to 1992.
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Between 6/83 and 8/92, 23 of 361 patients (6.4%) presenting at Vancouver General Hospital with acute myelogenous leukemia had acute promyelocytic leukemia (APL). Treatment plan was: 1) induction with high-dose cytosine arabinoside and an intercalator; and 2) consolidation with allogeneic bone marrow transplantation (BMT) for those aged < or = 50 years with a sibling donor or repeat of induction for the the others. Complete remission (CR) was achieved in 20 patients (87%). Eleven patients in CR were eligible for allogeneic BMT; 4 were considered unsuitable, 2 refused, and 5 underwent this treatment--1 died of acute graft-versus-host disease, 1 relapsed and 3 are leukemia-free and well 1.6, 3.3 and 3.9 years after diagnosis. Fifteen patients did not undergo allogeneic BMT in CR; 4 received no further treatment and all died, 2 relapsed before consolidation therapy and both died, 1 underwent autologous BMT and died of complications, and 8 received consolidation treatment as planned--1 died of sepsis, 2 relapsed and 5 are leukemia-free and well 1.0, 3.8, 4.5, 4.9 and 8.5 years after diagnosis. The actuarial overall survival for all 23 patients was 38% (95% confidence interval [CI] 18-57%). The actuarial 2-year leukemia-free survival was 60% (95% CI 20-85%) for the 8 patients who underwent consolidation chemotherapy as planned and 53% (95% CI 68-86%) for the 5 patients who underwent allogeneic BMT in CR. These results suggest that patients with APL who are able to undergo consolidation chemotherapy have a relatively good prognosis and allogeneic BMT may reasonably be held in reserve for salvage therapy.
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7787752
|
Epstein-Barr virus-associated hemophagocytic syndrome.
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A virus-associated hemophagocytic syndrome (VAHS) is a non-neoplastic, generalized histiocytic proliferation with prominent hemophagocytosis associated with a systemic viral infection. Epstein-Barr virus (EBV) is one candidate for this association but serologic and molecular biologic studies have been lacking in many cases. Although VAHS is generally a benign process, EBV-associated hemophagocytic syndrome (EBV-AHS) is often fatal and has a relatively high mortality rate. Therefore, EBV-AHS must be distinguished from VAHS caused by other viruses. Recent evidence indicates that the pathophysiology in EBV-AHS appears to be mediated by the unrestricted release of cytokines produced by the EBV-infected T cells. Clinical and laboratory findings, the differential diagnosis, virology studies, pathophysiology, and treatment in EBV-AHS are reviewed.
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7787751
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Cytokine gene expression after allogeneic bone marrow transplantation.
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Cytokines produced by T lymphocytes, monocytes/macrophages, and fibroblasts play a central role in the immune response and in the development of graft-versus-host disease (GVHD). Also, it has been reported that dysregulated production of cytokines maybe the primary mediator of clinical manifestation of acute GVHD. Regarding cytokine gene expression after human allogeneic bone marrow transplantation (allo BMT), we have demonstrated increased IL-1 beta, IL-6, and TNF-alpha mRNA expression in peripheral blood mononuclear cells during the development of acute and chronic GVHD and that the degree of the increase was dependent on the severity of the disease. Furthermore, overexpression of these cytokine mRNAs could be detected before the clinical manifestations of GVHD developed. In contrast, IL-2 mRNA expression was not detected in peripheral blood mononuclear cells in GVHD patients. On the other hand, we have reported that increased mRNA expression and protein product of IL-2 and IFN-gamma were evident in the mixed lymphocyte culture of the cases who developed severe lethal transplantation-related complications. Therefore, the detection of increased IL-2 and IFN-gamma gene expression in MLC appeared to be useful for predicting transplantation-related complications in BMT patients. Furthermore, we found increased IL-2 receptor alpha subunit mRNA expression in the peripheral blood mononuclear cells during GVHD. These findings may indicate the important role of inflammatory cytokines such as IL-1 beta, IL-6 and TNF-alpha in the development of the clinical manifestation of GVHD and also may be indicative of the important role of IL-2 and the IL-2 receptor in allo response perhaps mainly as an autocrine effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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7787749
|
Is there a place for immunotherapy with interleukin-2 to prevent relapse after autologous stem cell transplantation for acute leukemia?
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Chemotherapy-resistant cells cause disease recurrence in a significant proportion of patients with acute leukemia treated with autologous stem cell transplantation due to the lack of immune-mediated effects which contribute significantly to the prevention of post-treatment disease recurrence. This conclusion is based on the observation that relapse after high dose chemotherapy supported by a stem cell transplant from a twin donor is 3-4 times higher than after transplant from an allogeneic donor. This anti-leukemic mechanism of transplanted donor cells has been termed graft-versus-leukemia (GVL) effect, and efforts are being directed toward utilizing such an immune-mechanism after autologous transplantation. Since interleukin-2 (IL-2) can induce remissions in selected patients with advanced leukemia, it has become a candidate cytokine to be used in attempts to introduce GVL after autologous stem cell transplantation. Here we review the available clinical data with IL-2 and critically evaluate whether IL-2 has a place as adjunct treatment to prevent relapse after autologous transplantation for acute leukemia.
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7787750
|
Adhesion properties of adult T cell leukemia cells.
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The interaction between neoplastic as well as normal T cells and vascular endothelial cells which is mediated by adhesion molecules play a key role in their trafficking, localization and infiltration. This brief article reviews our studies on the expression of adhesion molecules on leukemic cells isolated from patients with adult T cell leukemia (ATL) and HTLV-I-infected T cell line cells and on their adhesion to human umbilical vein endothelial cells (HUVEC). Fresh ATL cells expressed lymphocyte function-associated antigen-1 (LFA-1), but the expression of very late antigen-4 (VLA-4) and sialyl-Lewis(x) (SLex) was variable. Sialyl Lewis(a) (SLea) was not detected. Cell adhesion assays using HUVEC and adhesion-blocking antibodies revealed the consistent E-selectin-mediated adhesion and variable VLA-4-mediated adhesion of ATL cells to HUVEC. The studies on HTLV-I-infected T cell lines confirmed the above data. These results, together with the detection of E-selectin expression on the endothelium of the skin infiltrated with ATL cells, indicate that E-selectin-mediated adhesion is the major pathway for the adherence of ATL cells to endothelial cells. The possible role of such adhesion in the formation of skin lesions and other clinical manifestations of ATL which result from the infiltration of leukemic cells is discussed.
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7787747
|
Differential usage of an autoantibody-associated VH gene, VH4-21, by human B-cell tumors.
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Selection of immunoglobulin variable region genes for recombination in B cells takes place from among those VH and VL gene segments available in the unrearranged germ line repertoire. In the case of neoplastic B cells, there is apparent deviation in the use of V-genes from that expected on a random basis, both for VH and for VL. Also, the preferred V-genes, and their patterns of mutation, differ among the various categories of B-cell tumor possibly reflecting the distinct origins and clonal histories on the individual tumor cells. This review focuses on a single VH gene, VH4-21, which is a member of the VH4 family, and which appears selectively to encode immunoglobulins with autoantibody activity, particularly anti-red cell antibodies. The pattern of usage of this VH gene by B-cell tumors demonstrates clear asymmetry among different tumor types. Also, the mutations detected in this relatively non-polymorphic gene indicate that antigen, possibly autoantigen, may influence the behavior of the tumor cell.
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7787748
|
Biopathologic features of Hodgkin's disease.
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The neoplastic nature of Hodgkin's disease (HD) is suggested by several lines of evidence, including aggressive clinical course, presence of proliferating atypical cells morphologically recognized as Hodgkin's and Reed-Sternberg cells (H-RS), aneuploidy, and, in the minority of cases, clonality. Nevertheless, the etiopathogenesis of HD still remains elusive, and probably diverse. This uncertainty is partly due to the peculiar histology of HD lesions, characterised by the paucity of the putative neoplastic cell component, i.e. H-RS cells, admixed to a variety of reactive cells which prevent an exhaustive investigation at molecular level. Nevertheless, the possible involvement of different molecules with oncogenic potential has been recently suggested on the basis of immunohistological and molecular biology studies. These include oncogenes such as bcl-2 and MDM2 and anti-oncogenes such as p53. In addition, a large amount of data has accumulated on the possible role of EBV infection in HD. The colonization of lymphoid tissues by immortalized H-RS cells can account for the derangement of cytokine networks leading to microenvironmental and systemic abnormalities. In addition, a variety of soluble receptors (sIL-2R, sCD30, sTNF-R), and adhesion molecules (sICAM-1) are abnormally produced at sites of disease involvement. Some of these molecules still retain the ability to bind their ligands and can potentially contribute to the derangement of immune mechanisms observed in HD. Many of these soluble molecules can also be found in the patient's sera providing new potential prognostic and follow-up parameters in HD patients. The comparative analysis of the same molecules within the tissue, using immunohistochemistry, and in the blood, using immunochemical assays, appears as a promising informative approach.
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7787746
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Acute leukemia with structural rearrangements of chromosome 3.
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Cytogenetic investigations have distinguished at least 3 distinct clinical-cytogenetic syndromes of hematopoietic malignancy with structural rearrangement of 3q. The majority of cases have breakpoints at both 3q21 and 3q26, frequently associated with monosomy 7, abnormal thrombopoiesis, and adverse outcome. Cases with only one of these breakpoints may have milder features of the syndrome. A subgroup with t(3q;5q) occurs in younger patients, occasionally with megakaryocytic dysplasia but rarely having thrombocytosis. The t(3;21) is encountered in secondary leukemias or after chemotherapy of myeloproliferative disorders. The genetic deregulations associated with each of these syndromes involve distinct genes on 3q. The majority of cases of acute leukemias with 3q rearrangements have a poor prognosis and do not respond to current modes of therapy.
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7787745
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Immunosuppression-associated lymphoproliferative disorders in rheumatic patients.
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The association between rheumatic disease and the occurrence of hematolymphoid neoplasms has been a subject of investigation for many years. Recently, we and others have reported the development in rheumatic patients of lymphoproliferative disorders that are similar to those occurring in patients with known immunocompromised states. The lymphoid neoplasms that develop in patients with immunosuppression are characterized by several features including the presence of EBV genome in the neoplastic cells. The fact that lymphomas with features of those occurring in immunosuppressed patients can occur in patients with rheumatic disease suggests that immune system impairment secondary to the rheumatic disease, the treatment given for the rheumatic disease, or to a combination of these factors, might play a role in the development of lymphoma in these patients. This review will first describe the characteristics of lymphoproliferative disorders that occur in patients with known immunocompromised states. It will then review general aspects of lymphomas in rheumatic patients with a focus on more recent reports that have described the development of immunosuppression-associated lymphoproliferative disorders in rheumatic patients. Studies that investigate the relative contribution of the rheumatic disease versus therapy for rheumatic disease in the development of lymphoma in this patient group are still needed.
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7787743
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Effects of preservation solutions on cortical and medullary mitochondria of rat kidney.
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The mitochondria isolated from cortex and medulla of rat kidneys were examined after storage in either Euro-Collins solution, in Bretschneider's histidine-tryptophan-ketoglutarat solution or in Belzer's University of Wisconsin solution at 25 degrees C or at 4 degrees C for a maximum of 4 to 24 hrs. Independently to the preservation of the solution used, the storage of the kidneys led to a decrease in state 3 respiration and uncoupled respiration as well as to an increase in the rate of state 4 respiration. The decrease in state 3 respiration ran parallelly to a decrease in adenine nucleotides. For the homogeneous protection of the mitochondria as well from the cortex as from the medulla, the Bretschneider's solution had the best preservative effect at a storage temperature of 25 degrees C as shown by the measured mitochondrial parameters. At 4 degrees C storage temperature, the differences in action with the various examined solutions were markedly smaller. However, compared to the other two solutions, the Euro-Collins solution showed a more favourable protective effect on cortical and medullary mitochondria.
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7787744
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Spontaneous lipid peroxidation and sperm metabolism during incubation in media simulating the oviductal microenvironment.
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It has been suggested that along the female genital tract spontaneous lipid peroxidation regulates the limit of the lifetime of spermatozoa. We have studied some aspects of rabbit and mouse spermatozoal metabolism during spontaneous lipid peroxidation in the course of the incubation in media which simulate the oviductal environment. The spermatozoa collected at regular intervals after the beginning of incubation were processed for cytochemical detection of cytochrome oxidase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activities. Quantitative cytochemical assays were made in situ in individual spermatozoa by microdensitometry. The cytochrome oxidase activity significantly decreased in both species because of damage to mitochondrial enzymes and membranes by radical and non-radical products of lipid peroxidation. The change in lactate dehydrogenase activity indicates that under our experimental conditions the lipid peroxidation process damages membrane permeability more markedly in mouse spermatozoa. The glucose-6-phosphate dehydrogenase activity, which should influence the concentration of reduced glutathione through production of NADPH, is more extensively enhanced in mouse spermatozoa than in rabbit spermatozoa. This is in agreement with the fact that in mouse spermatozoa the glutathione system is the major protective defence against oxidative damage while in rabbit spermatozoa it is superoxide dismutase.
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7787742
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Electron microscopic lectin histochemistry of the trabecular meshworks in human eyes.
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Ten normal human trabecular meshworks were examined by electron microscopy using avidin-biotin complex in order to investigate the localization of binding sites of eight lectins. The tissue specimens were fixed in paraformaldehyde and glutaraldehyde mixture and embedded in Lowicryl K4M at low temperature. The ultrathin sections were stained with biotin labelled lectins and colloidal gold labelled streptoavidin and were observed with the conventional transmission electron microscope. Some lectins such as ABA, ConA and DSA were localized on fine fibrils underneath the endothelium of the trabecular wall of the Schlemm's canal, electron-dense cores of elastic fibers, fine granular like materials, basement membranes, collagen fibers and the long-spacing fibers. However, the other lectins such as DBA, SBA, Lotus, UEA-I and RCA60 were not specifically localized in these tissues. From the results it was demonstrated that the differential ultrastructural localization of glycoconjugate residues in the human trabecular meshworks can be revealed using this lectin staining.
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7787741
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Morphological changes in human erythrocytes induced in vitro by antiarrhythmic drugs.
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Several hypotheses suggest that the molecular mechanism of action of class I antiarrhythmic drugs (AAD) involve non-specific interactions of these compounds with phospholipid bilayers of the myocardial membrane that surround and functionally modulate ion transport by sodium channels. As a result of these interactions the channel function would be altered. To probe the validity of these hypotheses three AAD with different degrees of lipophilicity were made to interact in vitro with human erythrocytes in a wide range of concentrations. The most lipophilic drug was asocainol (ASOC), the least one was procainamide (PROC) while the lipophilicity of the third, quinidine (QUIN), lay somewhere between the other two. The observations made by scanning electron microscopy (SEM) showed that the three AAD produced profound shape alterations to the incubated erythrocytes. However, the type and intensity of these changes were dependent on the drug under study and its concentration.
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7787740
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Internalization of Candida albicans and cytoskeletal organization in macrophages and fibroblasts treated with concanavalin A.
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This paper investigates the ability of macrophages and of non-typically phagocitic cells such as fibroblasts to internalize 51Cr-labelled C. albicans in presence or in absence of lectin concanavalin A (Con A). The results obtained demonstrate that fibroblasts are also able to internalize C. albicans and that this property is potentiated by the presence of Con A. Lectin modifies only the phenotype of the fibroblast, which, poorly attached to the substrate, is globular in shape. Despite reduced cellular spreading, phagocytosis is stimulated by the lectin. In both cell populations, changes in the organization of some cytoskeletal proteins such as tubulin, actin and alpha-actinin are evident during the C. albicans infection; such rearrangements are more evident and longlasting in the fibroblasts treated with Con A.
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7787739
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Correlation between membrane potential changes and proliferation of murine peritoneal lymphocytes stimulated by Nocardia water soluble mitogen.
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A comparative study of Nocardia water soluble mitogen (NWSM) action on membrane potential and proliferation rate of murine peritoneal lymphocytes was performed at various incubation times. The membrane surface charge was evaluated by laser doppler velocimetry (LDV) through the measurement of the cell electrophoretic mobility at different pH values (from pH 5 to 9). We demonstrated that NWSM treatment decreases the lymphocyte membrane potential. This variation reached a maximal level after 24 hrs. at pH 7 and remained unchanged during the 72 hrs. observation. A significant stimulation of lymphocyte proliferation was noted after a 24 hrs. incubation. However, the highest rate of [3H]-thymidine incorporation was observed at 48 hrs. with a subsequent decrease at 72 hrs. On the basis of these data, it is suggested, that membrane potential changes may represent an early important step in the mechanism of lymphocyte activation by NWSM, as it has been shown for some mitogenic compounds.
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7787738
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A new procedure for the preparation of highly active melonin from the dry seeds of Cucumis melo L.
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Melon (Cucumis melo L.) dry seeds contain melonin, a protein that strongly inhibits ribosomes from different prokaryotic and eukaryotic sources including those from melon. The protein was purified by a new method to yield highly active and stable protein preparations that involves chromatography through S-Sepharose Fast Flow, CM-Sepharose, Superdex 75 and Mono-S. Melonin shows important functional properties: 1) its inhibitory effects on translation were irreversible; 2) it is a single unglycosylated polypeptide chain with an apparent M(r) of 22000; 3) it degrades RNA in a dose-dependent way without affecting DNA. In the light of present results melonin can be considered as a new plant RNase of unusual properties.
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7787737
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Subcellular localization of gadolinium injected as soluble salt in rats: a microanalytical study.
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The rare earth gadolinium (Gd) is used in modern industry. Solubilized DTPA Gd and DOTA Gd complexes are used as contrast media in nuclear magnetic resonance imaging. In order to determine the subcellular localization of Gd, rats were injected intraperitoneally with Gd nitrate. Two microanalytic methods, ion microanalysis and electron microprobe, enabled the distribution and the intracellular localization of Gd to be determined in the liver, spleen, bone marrow, kidneys and lung. The results showed: a) a punctual distribution of Gd in the tissues (liver, spleen, bone marrow and lung) as observed by ion microscopy; b) a selective concentration of Gd in the lysosomes of macrophages of the liver (hepatocytes), spleen (macrophages), bone marrow (macrophages) and lung (phagocyte cells), as determined by electron probe X-ray microanalysis. In all these sites the Gd is associated to phosphorus. Results are compared to those found for other rare earths and metal elements.
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7787736
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Scanning ion microscopy mapping of basement membrane elements and arterioles in the kidney after selenium-silver interaction.
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The effects of selenium and silver salts was studied by scanning ionic microscopy during experimental argyria mapping of the different basement membrane elements. The ionic microscope (IMS 4F) was equipped with a high resolution spectrometer giving high spatial resolution on the image obtained. After long-term treatment with silver salt alone, silver and sulphur deposits were observed in the membranes. After administration of selenium and silver salt, it was possible to map nitrogen, sulphur, selenium and silver to the glomerular basement membrane as well as to the wall of the kidney arterioles. In the latter, sulphur, selenium and silver were localized only in the elastic laminae of the walls. This process of precipitation of silver deposits in the membrane can be interpreted as process of selenium "detoxification" of the organism.
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7787734
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Hypoxia and reoxygenation of brain endothelial cells in vitro: a comparison of biochemical and morphological response.
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Reactive oxygen species are thought to be important for a variety of pathological processes in the brain. Endothelial cells have been proposed as both a significant source of oxidants and targets of oxidative damage. Therefore, lipid peroxidation (LPO) was investigated and compared to biochemical and morphological alterations in cultured pig brain capillary endothelial cells after hypoxia (120 min. 95% N2/5% CO2) and reoxygenation (30 min. 95% O2/5% CO2). The content of thiobarbituric acid reactive substances (TBARS) representing radical-induced LPO was 2.50 +/- 0.46 after hypoxia and 5.92 +/- 0.54 nmol/mg protein after reoxygenation (p < 0.05 each, vs. normoxic control 1.79 +/- 0.21). During hypoxia, ATP content decreased to 7.9 +/- 1.6 nmol/mg protein; lactate dehydrogenase activity in the incubation solution increased to 0.17 +/- 0.03 U/mg protein; (p < 0.05 vs. control 15.7 +/- 3.1 and 0.09 +/- 0.02, respectively). After hypoxia, morphological changes in lysosomes, multivesicular bodies and vacuoles were observed in contrast to normoxic cells. During reoxygenation, the ATP values were normalized; electron micrographs showed increasing amounts of lysosomes, multivesicular bodies, vacuoles, blebs and lipofuscin granula and lyzed cells. Comparing the biochemical and morphological observations, a sequence of disturbances occurred, in which energy depletion was accompanied and followed, respectively, by membrane destruction, cellular disintegration and an increase in LPO products. These results support the assumption that the damage of brain endothelial cells caused by hypoxia and reoxygenation is accompanied by peroxidation of membrane lipids.
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7787735
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Differential expression of c-fos proto-oncogene in two subclones derived from a human ovarian cancer cell line.
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The expression of the c-fos proto-oncogene was studied in two sublines of the human ovarian cancer cell line SW626. One subline (SW/B) presents the typical 2.0 kb mRNA which is detectable within 15 min. after serum stimulation of quiescent cells, is inducible by protein synthesis inhibitors and has a half-life of approximately 10-15 min. The other subline (SW/A) does not show the 2.0 kb mRNA, but instead presents a mRNA of higher molecular weight capable of hybridizing with the c-fos probe. This bigger mRNA is neither serum inducible nor sensitive to protein synthesis inhibitors. The presence of this transcript is not due to any gross alteration in the gene structure. Differences were found in the DNA binding proteins obtained from nuclei of the two sublines. A protein able to bind the promoter of c-fos was found in SW/B but not in SW/A. In the latter subline no amplification products were observed using two different sets of primers covering the 3' coding region of the human gene. Conversely, the expected fragments were amplified from mRNA obtained from the SW/B subline.
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7787733
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Mixed culture of pericytes and endothelial cells from fetal microvessels of the human placenta.
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To explore the role of perivascular cells in angiogenesis and vasomotricity, placental cultures of perivascular cells were performed from calibrated villi excised from term placentas. Microvessels were isolated using repeated digestion of villi by collagenase-dispase and purification by Percoll gradients. Plated on Petri dishes, the microvessels became adherent to the gelatin matrix permitting to cells to proliferate. Cells were harvested and subcultured. Endothelial and pericyte cell lines were identified by phase contrast microscopy. Pericyte number predominated rapidly, the endothelial cells remaining visible. After seven days, cells started to cluster, thus piled up and built numerous nodules. Medium-size oval endothelial cells were stained by anti-von Willebrand factor and anti-IgG coupled to fluorescein. Large cells with irregular border reacted to smooth muscle anti-alpha-actin and anti-IgG coupled to fluorescein. There was no cross-reaction of these two cell types with the antibodies. In contrast, nodules were stained by both immunostainings. Endothelial cells reacting to von Willebrand factor antibody were frequently associated to the nodule. The isolation of microvessels from the human placenta described in this study allowed the establishment of cultures of endothelial cells and pericytes that show: i) rapid predominance of pericytes over endothelial cells, ii) formation of nodules, iii) participation of endothelial cells and pericytes to nodules formation.
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7787732
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Ileum brush border alkaline phosphatase activity in an experimental model of chronic alcoholism after small bowel proximal resection in the rat.
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Literature reports that chronically ingested ethanol induces changes in the morphology of the small bowel mucous membranes. It has a topical toxic effect on the epithelium of the proximal jejunum and a blood-borne effect on the epithelium of the ileum because its absorption is almost complete in the stomach, duodenum and proximal jejunum. In addition there are also reports showing stimulation of enterocyte proliferation after segmental intestine resection. In this report we compare a group of rats submitted to resection of the proximal jejunum and fed a liquid diet containing 35% of the total calories intake as ethanol for four weeks to its control pair-fed group. In both groups we studied the mucosal alkaline phosphatase (APase) activity by histochemical as well as biochemical methods. We found a decreased APase activity in the homogenate of the intestinal mucous membrane in the alcoholic group and a reduced enzymatic activity in the brush border of the ileum enterocytes, as demonstrated by histochemical qualitative and densitometric assays. The result suggests that this change in APase activity of the brush border may represent enterocyte immaturity induced by long-standing ethanol intake in the remnant ileum after proximal resection.
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7787731
|
Expression of S100 beta in sensory and secretory cells of the vertebrate inner ear.
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We evaluated anti-S100 beta expression in the chick (Gallus domesticus) inner ear and determined that: 1) the monomer anti-S100 beta is expressed differentially in the vestibular and auditory perikarya; 2) expression of S100 beta in the afferent nerve terminals is time-related to synapse and myelin formation; 3) the expression of the dimer anti-S100 alpha alpha beta beta and monomer anti-S100 beta overlaps in most inner ear cell types. Most S100 alpha alpha beta beta positive cells express S100 beta, but S100 beta positive cells do not always express S100 alpha alpha beta beta. 4) the expression of S100 beta is diffused over the perikaryal cytoplasm and nuclei of the acoustic ganglia but is concentrated over the nuclei of the vestibular perikarya. 6) S100 beta is expressed in secretory cells, and it is co-localized with GABA in sensory cells. 7) Color thresholding objective quantitation indicates that the amount of S100 beta was higher (mean 22, SD +/- 4) at E19 than at E9 (mean 34, SD +/- 3) in afferent axons. 8) Moreover, S100 beta was unchanged between E11-E19 in the perikaryal cytoplasm, but did change over the nuclei. At E9, 74%, and at E21, 5% of vestibular perikarya were positive. The data suggest that S100 beta may be physically associated with neuronal and ionic controlling cells of the vertebrate inner ear, where it could provide a dual ionic and neurotrophic modulatory function.
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