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Cystic goiter with squamous-cell metaplasia--case report and comment on origin of squamous-cell cyst. A 53-year-old woman with a left unilocular cystic goiter of the size of a small orange was reported. Approximately four-tenths of the innter surface was lined with several layered squamous epithelium with few follicles remaining. A gradual metaplastic transition from the follicular epithelium to the flattened cuboidal and to the squamous epithelium was observed. The ultimobranchial body has been understood to be a possible origin of an entirely squamous cell cyst of the thyroid, three of which have been reported. The difference between the ultimo-branchial and metaplastic origins will be discussed, and a new designation-primary (ultimo-branchial) and secondary (metaplastic) squamous-cell cyst will be proposed. | 16 |
Pain and the senses. There has been considerable philosophical debate over whether pain is a form of perception. A point of controversy is what pain is perception of; the best answer is neither pain-causing stimuli nor pain sensation but injury or the threat thereof. This answers the argument that pain cannot be perception because its 'objects' are private and exist only when perceived. A more potent argument is that pain is too poorly correlated with injury to count as perception of it. This issue is to be settled, in part, by determining the function of pain. The standard view of pain's function has here been contested and the resolution of the controversy will affect our inclination to ascribe to pain the status of perceptual faculty. | 12 |
Regulation of hepatic sterol metabolism in the rat. Parallel regulation of activity and mRNA for 7 alpha-hydroxylase but not 3-hydroxy-3-methylglutaryl-coenzyme A reductase or low density lipoprotein receptor. In vivo regulation of hepatic sterol metabolism was examined in the rat. Sodium cholate markedly suppressed hepatic 7 alpha-hydroxylase mRNA levels and activity when fed to rats on a low cholesterol diet. Sterol balance was maintained solely by decreasing hepatic cholesterol synthesis. Compensatory mechanisms were inadequate when cholate was fed to rats on a high cholesterol diet and massive amounts of cholesterol accumulated in the liver and plasma. Suppression of bile salt synthesis was not responsible since cholate did not suppress 7 alpha-hydroxylase activity when fed to rats on a high cholesterol diet. Moreover, total hepatic low density lipoprotein receptor activity was not suppressed even though liver cholesteryl ester levels were increased more than 350-fold. Changes in 7 alpha-hydroxylase activity were always accompanied by parallel changes in mRNA, whereas mRNA levels for 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase were reduced by 50% or less, even when cholesterol synthesis was suppressed by 98%. HMG-CoA reductase and low density lipoprotein receptor activities were regulated independently although mRNA levels for these two proteins were coordinately regulated. These findings indicate that 7 alpha-hydroxylase is controlled by mRNA levels, whereas in vivo cholesterol synthesis is predominantly controlled by posttranscriptional regulation of HMG-CoA reductase activity. | 18 |
Bilateral inverse Duane's retraction syndrome--a case report. Duane's retraction syndrome is a well known congenital musculo-facial anomaly. Various explanations have been given for the aetiology of this syndrome. Inverse Duane's retraction syndrome is a condition with reverse clinical features. Abduction of the affected eye is possible to some extent and is accompanied by retraction of the eyeball, narrowing of the palpebral fissure and pseudoptosis. There may be some restriction of movement on adduction. The primary lesion is suspected to be in the medial rectus muscle. Frequently the muscle is found to be entrapped following trauma to the medial wall of the orbit. A case of bilateral inverse Duane's retraction syndrome and convergent squint along with left-sided perceptive deafness is reported. As is usually the case there was no structural abnormality or entrapment of the muscle from trauma. | 12 |
Extracellular matrix components in bronchoalveolar lavage fluid in quartz exposed rats. To investigate the long term effects of quartz, bronchoalveolar lavage (BAL) and analysis of lung silica were performed in rats (n = 20) one, four, and 12 months after exposure to intratracheally instilled crystalline silica. Total and relative concentrations of silica in the lungs were highest one month after exposure. At this time BAL fluid concentrations of total cells, macrophages, and lymphocytes increased five to 10-fold compared with saline instilled controls (n = 19). The number of polymorphonuclear cells (PMNs) increased about 200-fold. The increased number of PMNs persisted during the year. Furthermore, albumin and fibronectin concentrations increased continually during the year, about two to fivefold the values of controls. Hyaluronan, by contrast, increased during the four month period (about eightfold) but decreased after one year to the one month concentration. Phospholipids in BAL fluid, raised already after one month, remained high at one year. The findings suggest progressive damage of the alveolar and interstitial tissues. Moreover, the increases in components of the extracellular matrix capable of building fibrotic networks are in agreement with the microscopical findings of fibrosis. Because only total cells, macrophages, and albumin concentrations correlated weakly with the silica contents of the lung, it is unlikely that the relation between quartz burden and the reaction in the lung is simple. | 14 |
Delayed flow of patients in a Black hospital. Two hundred consecutive patients who were discharged from a ward in a Black hospital were studied with reference to delay of flow through a system. Problems are discussed, e.g. that of the young patient, admitted at night, who awaits radiography and investigations. Because he is unable to give consent, he must wait for an operation until appropriate staff and consent are available. He recovers, may have to wait for a surgical appliance, is discharged and may then have to wait several more days before relatives collect him. The unique problems in Black hospitals can be alleviated, inter alia, by departmental admission protocols, outpatient liaison education officers, more even distribution of medical manpower, improved hospital transport systems and overnight stay wards incorporated in a more active outpatient system to replace the present sorting system. | 15 |
[The effect of the morphine antagonist naloxone on the effect of fentanyl]. 1. In healthy volunteers fentanyl (0.15 mg i.v.) induces a reduction of awareness and vigilance and in some persons a transition to sleepiness or sleep stages. The course of these changes with time can be shown in narcograms, consisting of vigilance indices which correspond to the different EEG-stages. 2. Naloxon (0.4--1.6 mg i.v.) reduces the hypnotic effect of fentanyl or antagonizes it completely. 3. Index values of rapid eye movements in wakefulness measured oculographically indicate a reduction of motor activity after administration of fentanyl, when stages of reduced vigilance appear. Injections of naloxone following later on diminish this effect of fentanyl or antagonize it completely, not so does levallorphan. | 11 |
Field ion microscopy of biomolecules. A new type of image, existing only at field strengths below the denaturation field strengths of molecules, has been discorvered. This type of image has structure, is not symmetrical and thus differs from previously reported low field strength images. The possibility that macromolecules adsorbed on tip surfaces produce such structured images has been exhaustively investigated. The result is that no observation has been found which disproves this hypothesis and many tests conducted in such attempts yielded correlations consistent with this hypothesis. It is therefore concluded that it is highly probable that biomolecules produce structured images and that it is highly improbable that these correlations represent a chance event. On the other hand, these correlations may be due to some cause unknown to the authors; but we consider this possibility to be unlikely. Some micrographs have been obtained which provide a reasonable basis for the hope that tertiary structure information may be defrived from low field strength imaging of partially embedded biomolecules or of biomolecules that are resistant to field denaturation during imaging. Information may presently be obtained from analysis of low field strength ion micrographs about the size and shape of some biomolecules. | 16 |
Cardiac biopsy in patients with "primary" atrial fibrillation. Histologic evidence of occult myocardial diseases. Fourteen patients (ten men and four women; mean age, 37 years) with lone atrial fibrillation (AF) (1 to 18 months' duration) were evaluated by thyroid function tests, two-dimensional echocardiography, hemodynamics, coronary angiography, and left ventricular endomyocardial biopsy, because of unresponsiveness to the usual antiarrhythmic therapy. The results of the T3, T4, TSH, and TRH tests were normal in all patients; cardiac valves and ventricular and atrial sizes (left atrium less than 40 mm) were within the normal limits; also normal were LVEDP (less than or equal to 10 mm Hg) and EF (greater than 0.50). Histologic findings were abnormal in all cases, with three patients showing cardiomyopathic changes, three other patients showing active myocarditis (lymphocytic in two and eosinophilic in one), and eight patients with nonspecific necrosis or fibrosis or both. Steroids (prednisone; 50 mg/m2 of body surface area daily) used in addition to antiarrhythmic therapy in patients with eosinophilic and lymphocytic active myocarditis were able to cause reversion to sinus rhythm, while the other patients continued to have AF. This study documents that occult myocardial diseases (myocarditis, cardiomyopathy, and nonspecific necrosis or fibrosis) can underlie "primary" AF. The addition of steroids to antiarrhythmic therapy in patients with refractory AF and histologic evidence of active myocarditis seems to be useful in controlling the arrhythmia. | 19 |
The effect of severity, consistency, and typicalness information on clinicians' causal attributions. Sixty-four clinicians responded to a brief description of a depressed student by indicating the extent to which each of four possible causes contributed to the depression. The descriptions were varied systematically so that the student's depression was described as either mild or severe, typical or atypical, and as having occurred before or as never having occurred before. Results indicated greater attribution of the depression to internal causal factors when the individual's depression was described as atypical and greater attribution to stable causal factors when the depression was described as having occurred previously. When the depression was described as severe, the clinicians tended to attribute it to external unstable causes. It was suggested that clinicians may differ from other populations in some of the causal attributions that they make for psychological difficulties. | 19 |
A physical analysis of the factors that determine the contour of the iris. By solving equations that result from the application of basic newtonian physical principles, I developed a model that can predict the profile of the iris by using only the pupil radius, the iris root radius, and the anterior displacement of the pupil from the iris root. The model requires some theoretically and clinically reasonable assumptions regarding the relative importance of forces acting on the iris. Former analyses made false assumptions about contact between the lens and the iris, as well as inappropriate substitution of the physical concept of force for tension. The validity of the new model and its inherent assumptions can now be tested with biometric measurements made in normal eyes and eyes with shallow anterior chambers. | 17 |
Squamous cell carcinoma in situ of the endometrium and fallopian tube as superficial extension of invasive cervical carcinoma. Five cases of squamous cell carcinoma of the cervix associated with widespread squamous cell carcinoma in situ of the endometrial surface are reported. In one case, carcinoma in situ was also found in one fallopian tube in continuity with the cervicoendometrial lesion. A survey of the literature reveals only 20 cases with similar surface endometrial involvement by cervical squamous cell carcinoma. Of these, the fallopian tubes were involved by an identical lesion in six cases only. Pyometra and cervical stenosis were reported in about 66% of the cases. This rare form of upward cervical cancer extension was present in five of 680 cases (0.7%) of squamous cell carcinoma of the cervix in the file of the Tumor Registry of Magee-Womens Hospital. | 15 |
Flavones. 3. Synthesis, biological activities, and conformational analysis of isoflavone derivatives and related compounds. A series of 2-alkylisoflavone derivatives 1 was prepared with the intent to study the importance of the phenyl group (at the 3-position) of the isoflavone in imparting antihypertensive activity and the substitution effects at the 2-position of isoflavone. With the exception of the 2-isopropyl analog, the antihypertensive activity of these compounds appears to have a slow onset and long duration. None of the analogs appears better than the corresponding flavone (3) and 3-phenylflavone (2) analogs. An unsuccessful attempt to correlate the relationship between antihypertensive activity and the calculated torsional angle of C2-C3-C1'-C2' is discussed. Antiinflammatory activities of these compounds along with 7-(oxypropylamine)flavones were also evaluated and found to be not very potent. The antiinflammatory activity appears to be sensitive to steric effects of the alkyl group on the nitrogen and of substituents at the 2-position of the isoflavones, while the hydroxyl group of the propanolamine side chain is not essential. | 16 |
Coronary vasodilation by fatty acids. Fatty acids increase the coronary flow rate of rat hearts, perfused according to the Langendorff technique. Long-chain and medium-chain fatty acids are more effective vasodilators than short-chain fatty acids. The vasodilatation by fatty acids does not proceed through the intermediate formation of the vasodilator adenosine, nor by stimulation of adenylcyclase activity. Since at low Ca2+ concentrations fatty acids not only stimulate the coronary flow rate but also cardiac contractility, it is suggested that especially the lipophilic fatty acids have calcium ionophoric properties leading to increased Ca2+ removal from smooth muscle cytosol and hence to vasodilatation. Preliminary experiments, moreover, indicate that both medium- and long-chain fatty acids, like prostaglandin E1 and Ca2+, inhibit membrane ATPase(s) of aorta smooth muscle cells, suggesting increased Ca2+ binding to vascular smooth muscle cell membranes. | 18 |
Psychological stress and susceptibility to the common cold. It is not known whether psychological stress suppresses host resistance to infection. To investigate this issue, we prospectively studied the relation between psychological stress and the frequency of documented clinical colds among subjects intentionally exposed to respiratory viruses. After completing questionnaires assessing degrees of psychological stress, 394 healthy subjects were given nasal drops containing one of five respiratory viruses (rhinovirus type 2, 9, or 14, respiratory syncytial virus, or coronavirus type 229E), and an additional 26 were given saline nasal drops. The subjects were then quarantined and monitored for the development of evidence of infection and symptoms. Clinical colds were defined as clinical symptoms in the presence of an infection verified by the isolation of virus or by an increase in the virus-specific antibody titer. The rates of both respiratory infection (P less than 0.005) and clinical colds (P less than 0.02) increased in a dose-response manner with increases in the degree of psychological stress. Infection rates ranged from approximately 74 percent to approximately 90 percent, according to levels of psychological stress, and the incidence of clinical colds ranged from approximately 27 percent to 47 percent. These effects were not altered when we controlled for age, sex, education, allergic status, weight, the season, the number of subjects housed together, the infectious status of subjects sharing the same housing, and virus-specific antibody status at base line (before challenge). Moreover, the associations observed were similar for all five challenge viruses. Several potential stress-illness mediators, including smoking, alcohol consumption, exercise, diet, quality of sleep, white-cell counts, and total immunoglobulin levels, did not explain the association between stress and illness. Similarly, controls for personality variables (self-esteem, personal control, and introversion-extraversion) failed to alter our findings. Psychological stress was associated in a dose-response manner with an increased risk of acute infectious respiratory illness, and this risk was attributable to increased rates of infection rather than to an increased frequency of symptoms after infection. | 18 |
Relationships between membrane antigens of human leukemic cells and oncogenic RNA virus structural components. Leukemic cells from all human chronic granulocytic leukemia (CGL) and some acute myelomonocytic leukemia (AMML) donors are lysed by rabbit antisera to a purified glycoprotein of Friend murine leukemia virus (FLV gp71) in a microcytotoxicity assay. These antisera are not cytotoxic to cells from patients with acute myelocytic leukemia (AML), acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), or to peripheral blood lymphocytes from normal donors. A goat antiserum to gradient purified FLV in addition to reacting with cells from CGL and AMML donors also reacted with cells from AML patients and some ALL donors. However, this antiserum failed to react with cells from CLL patients. Peripheral blood and bone marrow leukocytes prepared from leukemic patients in clinical remission failed to react with antisera to FLV and FLV gp71. Absorption experiments demonstrated that the antigen on CGL cells which is reacting with the antiserum to FLV gp71 is also present on normal human platelets and neutrophils. Similar absorption studies showed that the antigen on AML cells detected by the FLV antiserum is not present on normal leukocytes and platelets and appears to be related to the major internal p30 antigens of mammalian RNA tumor viruses. Another antigenic relationship between oncornaviruses and membrane antigens of human leukemia cells was shown by the ability of FLV antigens to absorb the cytotoxic reactivity of nonhuman primate antisera detecting human leukemia-associated antigens. FLV and FLV gp71 antigens were able to absorb all cytotoxic activity of monkey and chimpanzee antisera to human myeloid leukemia antigens when these antisera were tested with CGL cells. These two approaches to an analysis of cross-reactivity indicate that the antigenic determinant(s) detected by the cytotoxic reactions of the FLV gp71 antiserum with human CGL cells is different from the determinant on FLV gp71 which is responsible for the inhibition of the reactivity of simian antisera with CGL cells. Since the goat and rabbit antisera to FLV and FLV gp71 are able to distinguish AML from CGL cells by direct cytotoxicity testing and absorption, they may be valuable reagents for the serological diagnosis of myeloid leukemia. In addition, since peripheral blood cells from AML and CGL patients in clinical remission were seronegative, the antisera may be valuable as management aids. The data in this report indicates that whatever the mechanism of leukemogenesis is in man, cells from CGL and AML patients possess certain membrane antigens which cross-react with FLV structural components such as p30 and gp71. | 20 |
Assessment of retrovirus-expressed nucleoprotein as a vaccine against lethal influenza virus infections of chickens. Hemagglutinin-based influenza vaccines stimulate protection in chickens that is limited to the serotype of the expressed hemagglutinin. To evaluate whether a more highly conserved influenza virus protein might stimulate a broader protective response, the influenza virus nucleoprotein (NP) was introduced into a retroviral vector (mRCAS/NP). NP is an internal influenza virus protein that has been shown to stimulate cytotoxic T-cell responses in influenza-virus-infected mice. Cells infected with mRCAS/NP expressed approximately 10% of the level of NP observed in influenza-virus-infected chicken embryo fibroblasts. Immunocompetent chicks were vaccinated intramuscularly with approximately 1 x 10(5) NP-expressing units of mRCAS/NP. Four weeks later, chicks were bled and challenged with a highly pathogenic avian influenza virus (A/Chicken/Victoria/1/85). The NP-expressing vector stimulated an influenza-virus-specific response, as indicated by the presence of antibody to NP, but failed to protect against the lethal challenge. | 16 |
Response of serum LH, FSH and prolactin to injection of synthetic LH-RH into rat anterior pituitary. Changes in serum LH, FSH and prolactin were measured by radioimmunoassay following injection of synthetic LH-RH into the anterior pituitary and median eminence of rats. The time course of serum levels of LH and FSH after injection of synthetic LH-RH into the pituitary showed a peak at 15 min. The synthetic LH-RH had a more marked releasing effect on LH than on FSH. After injection of 20 ng into the pituitary, the serum LH rose to about 10.7 times the control level but the serum FSH only to about 1.8 times. A significant rise of serum LH over the control level was noted after injection of more than 0.2 ng of synthetic LH-RH, while that of serum FSH was after injection of more than 2 ng. An injection of 2 ng of synthetic LH-RH into the pituitary following 0.1 mug of estradiol benzoate resulted in a fall of serum LH and FSH levels, and a rise of serum prolactin level. An injection of 2 ng of synthetic LH-RH into the median eminence resulted in a tendency towards slight decrease in serum LH and FSH. No significant response of serum prolactin to synthetic LH-RH was noted. | 14 |
D2 dopamine receptors in the human retina: cloning of cDNA and localization of mRNA. 1. We have obtained a cDNA clone encoding a human retinal D2 dopamine receptor. 2. The longest open reading frame (1242 bp) of this clone encodes a protein of 414 amino acids having a predicted molecular weight of 47,000 and a transmembrane topology similar to that of other G protein-coupled receptors. 3. Transient transfection of COS-7 cells with an expression vector containing the clone resulted in expression of a protein possessing a pharmacological profile similar to that of the D2 dopamine receptor found in striatum and retina. 4. Northern blot analysis indicated that, in rat brain and retina, the mRNA for this receptor was 2.9 kb in size. 5. In situ hybridization was performed to examine the distribution of the mRNA for this receptor in human retina. Specific hybridization was detected in both the inner and the outer nuclear layers. 6. These findings are consistent with prior physiological and autoradiographic studies describing the localization of D2 dopamine receptors in vertebrate retinas. Our observations suggest that photoreceptors as well as cells in the inner nuclear layer of human retinas may express the mRNA for this D2 dopamine receptor. | 12 |
Selective mesenteric phlebography in patients with carcinoid tumors. Seventeen patients were investigated to localize carcinoid tumor growth in the small intestine and liver. Portography, selective phlebography of the intestinal veins, arteriography, and hormone assay (Serotonin, substance P) after simultaneous catheterization of the celiac artery and portal and caval veins were performed. Most of the patients have been operated on and findings at surgery have been compared with the preoperative localization methods. In 3 cases with small bowel carcinoids and typical fibroplastic changes of the mesentery, phlebography as well as arteriography demonstrated well the degree of mesenteric involvement. None of the methods demonstrated the primary tumors. Arteriography was superior in demonstration of liver metastasis. The hormone assay was a useful complement to angiographic techniques in the diagnosis and localization of tumor growth. | 15 |
Location of the two catalytic sites in intestinal lactase-phlorizin hydrolase. Comparison with sucrase-isomaltase and with other glycosidases, the membrane anchor of lactase-phlorizin hydrolase. Lactase-phlorizin hydrolase was isolated by immunoadsorption chromatography from rabbit brush-border membrane vesicles. Inactivation of the enzyme with [3H]conduritol-B-epoxide, a covalent active site-directed inhibitor, labeled glutamates at positions 1271 and 1747. Glu1271 was assigned to lactase, Glu1747 to phlorizin hydrolase activity. In contrast, the nucleophiles in the active sites of sucrase-isomaltase are aspartates (Asp505 and Asp1394). Asp505 is a part of the isomaltase active site and is localized on the larger subunit, which carries the membrane anchor also, while Asp1394 is a part of the active of sucrase. Alignment of these 2 nucleophilic Glu residues in lactase-phlorizin hydrolase and of their flanking regions with published sequences of several other beta-glycosidases allows the classification of the configuration retaining glycosidases into two major families: the "Asp" and the "Glu" glycosidases, depending on the carboxylate presumed to interact with the putative oxocarbonium ion in the transition state. We offer some predictions as to the Glu acting as the nucleophile in the active site of some glycosidases. By hydrophobic photolabeling, the membrane-spanning domain of lactase-phlorizin hydrolase was directly localized in the carboxyl-terminal region thus confirming this enzyme as a monotopic type I protein (i.e. with Nout-Cin orientation) of the brush-border membranes. A simplified version of the Me2+ precipitation method to efficiently and simply prepare brush-border membrane vesicles is also reported. | 16 |
[Pseudomembranous colitis due to clindamycine. A new case (author's transl)]. A recent case has provided an opportunity for the observation of pseudomembranous colitis occurring after the ingestion of Clindamycine prescribed for a dental abscess. In this condition, the pathogenesis of which remains unclear, there is relative variability in the time taken for clinical signs to appear, as well as in their subsequent duration, but endoscopic and histological findings do however, in the particular context, frequently justify a sure diagnosis. Radiographic examination most often indicates a nonspecific inflammation. Curative treatment is essentially symptom oriented, while the prevention of such complications demands, in addition to close supervision of patients under this medication, particularly strict eclectism in the selection of indications for its administration. | 18 |
Migration and aggregation of embryonic chicken neurons in vitro: possible functional implication of polysialogangliosides. The presented study reports a primary culture system of embryonic chicken optic lobe neurons, which turned out to be a suitable model for cell migration and aggregation: Freshly dissociated neurons developed short processes, contacted one another and formed fasciculated bundles, on which neurons migrated as long-shaped cells, similar to migrating neurons in vivo. We used this system to study the possible involvement of c-pathway polysialogangliosides for neuronal migration and aggregation. These highly negative charged glycosphingolipids are the predominant gangliosides of migrating and outgrowing neurons in vivo. Addition of a purified ganglioside mixture (50 microM), extracted from brains of the corresponding embryonic stage, strongly enhanced neuronal migration and aggregation, while incubation of the cells with monoclonal antibody Q211, specifically binding c-polysialogangliosides, reduced aggregate formation in a dose-dependent manner. Cultures treated with 10 micrograms/ml Q211, instead, displayed a more divergent growth, leading to the formation of a fine network of single neuronal processes. These results suggest a functional implication of c-polysialogangliosides in neuronal fasciculation, migration and aggregation. | 21 |
Inhibition of peptidase and glycosidase activities of Porphyromonas gingivalis, Bacteroides intermedius and Treponema denticola by plant extracts. Aqueous extracts from 5 plants used widely in Kenya as chewing sticks (mswaki) for the control of oral hygiene were tested for their ability to inhibit extracellular peptidase and glycosidase enzyme activities produced by the periodontopathic bacteria Porphyromonas gingivalis (formerly Bacteroides gingivalis), Bacteroides intermedius and Treponema denticola. The plants studied were Rhus natalensis, Cupressus hisitanica, Sida cordifolia, Olea africana and Euclea divinorum. Protease activities, including glycylprolyl dipeptidase and trypsin-like activities of P. gingivalis, chymotrypsin-like and glycylprolyl dipeptidase activities of B. intermedius and the trypsin-like activity of T. denticola, were particularly affected by extracts from Rhus natalensis and Euclea divinorum. Glycosidase activities were generally less affected with the notable exceptions of the inhibition of beta-mannosidase activity of P. gingivalis by all extracts and the inhibition of neuraminidase activity of T. denticola by Rhus natalensis and Euclea divinorum. Generally, these same proteolytic and glycosidic activities were inhibited by tannic acid and to lesser extents by gallic acid and gallic acid methyl ester. An inhibitory component, present in all extracts, exhibited physical and chemical properties identical to those of tannic acid. The inhibition of these enzyme activities is likely to reduce the virulence of these periodontophathic bacteria and to reduce the rate of dental plaque formation. | 23 |
Emergency departments and crowding in United States teaching hospitals. To assess the extent and distribution of hospital and emergency department crowding nationally. The research design consisted of a mailed questionnaire disseminated in the fall of 1988 to the member institutions of the National Association of Public Hospitals (NAPH) and the Council of Teaching Hospitals (COTH). Study participants included hospital administrators and ED directors from 239 of the non-Veterans Administration, general acute care, US members of COTH and NAPH. Key measures of hospital and ED crowding including mean ED holding times for floor and ICU beds. Three fourths of responding hospitals reported increases in ED visits over the preceding three years. Mean ED holding times for admitted patients were 3.5 hours (median, 2.0 hours) for a floor bed and 2.9 hours (median, 1.5 hours) for an ICU bed. Half of all hospitals noted maximum waits for floor and ICU beds of ten hours or more and seven hours or more, respectively. Measures taken by hospitals to manage crowding during August 1988 included restricting access to some types of patients (mean, 3.6 days), actively transferring patients to other hospitals (mean, 2.2 days), transfer refusal (mean, 2.8 days), and total ambulance diversion (mean, 1.6 days). Our study strongly suggests that ED crowding is not an isolated phenomenon; ED crowding and its attendant problems appear to affect hospitals with similar adverse effects regardless of ownership. Although our results suggest that ED crowding is concentrated in metropolitan areas and in a smaller subset of hospitals, we found instances of crowding among hospitals nationwide. | 15 |
[Proto-oncogene C-erbB-2 and human cancer]. The C-erbB-2 gene was first found in human genomic DNA as a sequence which had homology in nucleotide sequence to the V-erbB by molecular hybridization under relaxed conditions. The product of this gene is a receptor type protein-tyrosine kinase which has a structure highly related to that of epidermal growth factor receptor (EGF-r: C-erbB-1). The proto-neu gene is a rat counterpart of the C-erb B-2 gene. The C-erbB-2 gene is also called as the HER-2 gene. The C-erbB-2 gene acquires the ability to transform NIH 3 T 3 cells by, 1) mutation which alters valine 659 in transmembrane region to glutamic acid as was found in neu gene activation, 2) deletion of c-terminal regulatory domain or 3) gene-amplification or overexpression. C-erbB-2 expresses in human embryos on mucous membranes and glands, but only faintly in adult tissues. High expression or gene amplification in human tumor appeared to be an indication for high risk of metastasis or high degree of malignancy. | 13 |
[An occurrence of a neurogenic sarcoma in an irradiated field following the combined surgical-radiologic treatment of a childhood adenosarcoma of the kidney]. Malignant neoplasias in childhood generally are an increased risk for the patient to fall ill with a second tumor. Second tumors in former irradiation field are seldom, but are acknowledged radiogenically if histology is different to that of the first tumor and a sufficiently long period is between the two tumors. A patient is represented who had been operated and irradiated because of an adenosarcoma of the kidney at the age of seven and who has fallen ill with a neurogenic sarcoma in irradiation area more than 30 years later. The same patient had to suffer from radiogenic retardation during differentiation of lumbar apparatus of attitude and locomotion and on the other hand he became father of a healthy daughter at the age of 32. | 19 |
Conformational change of the coronavirus peplomer glycoprotein at pH 8.0 and 37 degrees C correlates with virus aggregation and virus-induced cell fusion. We have obtained biochemical and electron microscopic evidence of conformational changes at pH 8.0 and 37 degrees C in the coronavirus spike glycoprotein E2 (S). The importance of these changes is reflected in the loss of virus infectivity, the aggregation of virions, and increased virus-induced cell fusion at the same pH. Coronavirus (MHV-A59) infectivity is exquisitely sensitive to pH. The virus was quite stable at pH 6.0 and 37 degrees C (half-life, approximately 24 h) but was rapidly and irreversibly inactivated by brief treatment at pH 8.0 and 37 degrees C (half-life, approximately 30 min). Virions treated at pH 8.0 and 37 degrees C formed clumps and large aggregates. With virions treated at pH 8.0 and 37 degrees C, the amino-terminal peptide E2N (or S1) was released from virions and the remaining peptide, E2C (S2), was aggregated. Viral spikes isolated from detergent-treated virions also aggregated at pH 8.0 and 37 degrees C. Loss of virus infectivity and E2 (S) aggregation at pH 8.0 and 37 degrees C were markedly enhanced in the presence of dithiothreitol. On the basis of the effects of dithiothreitol on the reactions of the peplomer, we propose that release of E2N (S1) and aggregation of E2C (S2) may be triggered by rearrangement of intramolecular disulfide bonds. The aggregation of virions and the isolated E2 (S) glycoprotein at pH 8.0 and 37 degrees C or following treatment with guanidine and urea at pH 6.0 and 37 degrees C indicate that an irreversible conformational change has been induced in the peplomer glycoprotein by these conditions. It is interesting that coronavirus-induced cell fusion also occurred under mildly alkaline conditions and at 37 degrees C. Some enveloped viruses, including influenza viruses and alphaviruses, show conformational changes of spike glycoproteins at a low pH, which correlates with fusion and penetration of those viruses in acidified endocytic vesicles. For coronavirus MHV-A59, comparable conformational change of the spike glycoprotein E2 (S) and cell fusion occurred at a mildly alkaline condition, suggesting that coronavirus infection-penetration, like that of paramyxoviruses and lentiviruses, may occur at the plasma membrane, rather than within endocytic vesicles. | 20 |
[Role of ventrolateral medulla in pressor response elicited by stimulation of abdominal vagi in cats]. The experiments were performed on 51 cats of either sex weighing 1.8-2.4 kg to investigate the role of the ventrolateral medulla in the pressor response elicited by stimulation of central ends of abdominal vagi. We observed that both the stimulation of the central ends of abdominal vagi and occlusion of one carotid artery increased the blood pressure by 17.4 +/- 1.6 mmHg (n = 51, P less than 0.01) and 14.7 +/- 1.9 mmHg (n = 19, P less than 0.01) respectively; blockade of the caudal ventrolateral medulla or trapezoid bodies with lidocaine had little effect on blood pressure and the pressor response, but blockade of the rostral ventrolateral medulla with either lidocaine or kainic acid could cause profound depression, and even abolition, of the pressor response. Moreover, application of atropine and phentolamine to the RVL severely inhibited the abdominal vagal pressor response without affecting the baroreceptor reflex. Taken together, we conclude that the RVL is a very important relay in the pathway of the abdominal vagal pressor response in which the adrenergic and cholinergic mechanisms may be involved in the RVL, and it seems that the pressor response pathway is independent of that of the baroreceptor reflex in the RVL. | 26 |
DNA synthesis in isolated arteries. Kinetics and structural consequences. We evaluated changes in DNA synthesis, structure, and mechanical activity in isolated arteries during exposure to growth factors. Renal arteries were isolated from rats, sympathectomized, denuded of endothelium, and maintained in tissue culture. Up to 4 days of culture did not affect maximal contractile responses to depolarization. From the results of nuclear incorporation of the thymidine analogue 5-bromo-2-deoxyuridine (BrdUrd), culture stimulated DNA synthesis. In the media, incorporation of BrdUrd was maximal after 3 days but fell precipitously thereafter. Culture of arterial segments did not, however, increase the cross-sectional area of the media, the ploidy of the arterial nuclei, or the number of medial cells. In contrast, new layers of cells, part of which displayed smooth musclelike properties, developed at the border of the segments. The outermost edge of this newly formed layer continued to incorporate BrdUrd for at least 2 wk. These data demonstrate that stimulation of DNA synthesis by continuous exposure of the arterial wall to exogenous growth factors is 1) transient in the media; 2) does not, at least initially, compromise contractile reactivity; 3) does not alter gross medial structure; but 4) leads to proliferation of smooth musclelike cells outside the media. These findings suggest that the number of smooth muscle cells in the arterial media is maintained constant in the presence of even strong mitogenic stimuli. | 14 |
Stability of positive tuberculin tests: are boosted reactions valid? To determine the stability and presumed significance of tuberculin skin tests, we followed a cohort of 380 tuberculin-positive patients living in chronic care facilities. Each patient had a positive reaction (greater than or equal to 10 mm induration to 5 tuberculin units of purified protein derivative) to one of three sequential baseline tuberculin tests. One year after the initial series, each patient had a single repeat skin test. Reversion to a negative test occurred in 98 (26%) of the 380 patients. Decreases in induration of 6 mm or more occurred in 88 (90%) of the reverters. Initially positive tests were more likely (p less than 0.001) to remain stable than tests that were "boosted" to positive reactions on the second or third initial administration. Stable responses were found in 96% of those whose tests had greater than or equal to 15 mm induration compared with 61% of those with reactions of 10 to 14 mm induration. Increasing age also was associated with a high rate of reversion. The instability of boosted tuberculin reactions brings into question the clinical significance of these tests. We propose limiting tuberculin testing to two sequential tests. | 13 |
Endoscopic therapy for acute nonvariceal upper gastrointestinal hemorrhage: a meta-analysis. Endoscopic hemostatic therapy for upper gastrointestinal bleeding is gaining widespread acceptance despite often conflicting results of randomized controlled trials. To examine the effect of endoscopic therapy in acute nonvariceal upper gastrointestinal hemorrhage, a meta-analysis was performed using a computerized search of the English-language literature and a bibliographic review. The methodology, population, intervention, and outcomes of each relevant trial were evaluated by duplicate independent review. Thirty randomized controlled trials evaluating hemostatic endoscopic treatment were identified. Endoscopic therapy significantly reduced rates of further bleeding (odds ratio, 0.38; 95% confidence interval, 0.32-0.45), surgery (odds ratio, 0.36; 95% confidence interval, 0.28-0.45), and mortality (odds ratio, 0.55; 95% confidence interval, 0.40-0.76). When analyzed separately, thermal-contact devices (monopolar and bipolar electrocoagulation and heater probe), laser treatment, and injection therapy all significantly decreased further bleeding and surgery rates. The reductions in mortality were comparable for all three forms of therapy, but the decrease reached statistical significance only for laser therapy. Further examination of subgroups indicated that endoscopic treatment decreased rates of further bleeding, surgery, and mortality in patients with high-risk endoscopic features of active bleeding or nonbleeding visible vessels. Rebleeding was not reduced by endoscopic therapy in patients with ulcers containing flat pigmented spots or adherent clots. Endoscopic hemostatic therapy provides a clinically important reduction in morbidity and mortality in patients with acute nonvariceal upper gastrointestinal hemorrhage. | 20 |
Non-specific potentiation of IgE by parasitic infections in man. Infection with the helminthic parasites Ascaris lumbricoides and/or Necator americanus (hookworm) induces the production in man of high levels of serum IgE. The specificity of this IgE antibody when measured by RAST to a wide range of allergens was restricted in general to the helminthic antigens. Absorption of the sera with immunosorbents produced by coupling extracts of A. lumbricoides to CNBr activated Sepharose 4B established that Ascaris antigen specific IgE antibodies contributed a minor fraction of the total serum IgE. These observations suggest that parasitic infections in man as in laboratory animals potentiate the production of high levels of IgE with specificity unrelated to that of the parasite antigens. While the specificity of this potentiated IgE was not established, it is not directed towards inhalant allergens. | 18 |
A radioimmunoassay for the estimation of serum dehydroepiandrosterone sulphate in normal and pathological sera. A radioimmunoassay is described for the measurement of dehydroepiandrosterone sulphate in serum. The method requires 0.1 ml of serum that needs no purification other than a single ether extraction. It is both rapid and economical, procedural losses are small and precision and accuracy are acceptable for both normal and pathological sera. Normal values have been established for children and adults which show a relationship to chronological age, values rising steadily as puberty intevenes, peak values occurring between 20 and 27 years, with a decline thereafter. An empirical curve was fitted to the data and approximate normal limits were obtained. The mean value for pregnanat women in the age range 20-40 years, was statistically significantly lower than in non-pregnant, premenopausal women. The levels of dehydroepiandrosterone sulphate in cord and newborn blood, were higher than at any other time during childhood until signs of puberty were demonstrable. Elevated levels are reported in six patients with untreated congenital adrenal hyperplasia and in one patient with a tumour of the adrenal cortex. It is suggested that this assay provides a useful and precise index of adrenal androgen secretion. | 15 |
The serum-inducible mouse gene Krox-24 encodes a sequence-specific transcriptional activator. The mouse gene Krox-24 is transiently activated during cell cycle reentry. It encodes a protein with three zinc fingers similar to those of the transcription factor Sp1. Here we present a biochemical characterization of the gene products. Krox-24 mRNA is translated into two proteins of 82 and 88 kilodaltons, designated p82Krox-24 and p88Krox-24, respectively. p82Krox-24 is initiated at the first AUG codon of the open reading frame, whereas synthesis of p88Krox-24 starts at a non-AUG codon located upstream. Both proteins were synthesized in HeLa cells infected with recombinant vaccinia viruses expressing Krox-24 cDNAs. Under these conditions, they were found phosphorylated on serine residues and glycosylated. The availability of the proteins made possible the determination of the DNA recognition sequence. In vitro, Krox-24 bound specifically to the sequence 5'-GCG(C/G)GGGCG-3'. This sequence is similar but not identical to the Sp1 target sequence. Insertion of an oligomer for the binding site in cis, close to the herpes simplex virus thymidine kinase promoter, rendered this promoter responsive to Krox-24. Krox-24 is therefore a sequence-specific transcriptional activator. Krox-24-binding sites were found upstream of several serum-inducible genes, raising the possibility that Krox-24 is involved in the regulation of these genes. | 12 |
Method of choice for urinary diversion in surgical treatment of bladder carcinoma. Evidence is presented concerning 94 patients with malignancy of bladder in whom diversion of urine was performed after cystectomy for exclusion of the bladder. There were 80 men and 14 women, ages ranging from 30 to 81 years. In 35 of these 94 cases ureterosigmoidoanastomosis, in 38 cases ureterocutaneostomy, in 15 Portilla's operation, in 2 Bricker's method and in 4 nephro-pyelostomy were performed. For the prevention of bleeding cystectomy was preceded by bilateral ligation of the internal iliac artery in 14 cases. Continuous postoperative follow-up of the patients (from a few months to 14 years) and analysis of the early and late results allow to regard the combined technique of Coffey II-Nesbit-Goodwin as the method of choice having the slightest risk of peritonitis, intestinoureteral reflux and other complications inherent in other procedures. Of the existing methods of ureterocutaneostomy the authors have chosen Le Dentu's method with some modifications. They consider ureterostomy to be the simplest and quickest method owing to the higher location of ureterostoma. Portilla's method is no longer used because of its unfavourable long-term results. Of 94 patients with cancer of the bladder, who had been subjected to different methods of urinary diversion in the years 1954-1974, 16 have survived up till now. There are 10 survivors after ureterosigmoidoanastomosis, 5 after ureterocutaneostomy and 1 after Bricker's operation. | 15 |
Pathophysiology of Cushing's disease. The term Cushing's disease is applied to those cases of Cushing's syndrome in which hypercortisolism is secondary to inappropriate secretion of ACTH by the pituitary. Studies on control of ACTH secretion in these patients reveal: (a) that the episodic secretion of ACTH is similar to the normal; however, frequency and amplitude of the secretory episodes lack the normal circadian rhythm; (b) that ACTH release can be stimulated by vasopressin and metyrapone in a normal or above-normal manner; and (c) that it can be suppressed by large doses of corticosteroids. When the dynamic aspects of the ACTH response to corticosteroid administration are studied, it appears that the normally negative differential feedback mechanism is converted into a positive one, whereas the delayed, integral mechanism is undisturbed. Patients with Cushing's disease in the presence of obvious pituitary tumors cannot be distinguished from those without pituitary tumors by studying only the pituitary function. All these and other well-known facts would favor the concept that ACTH secretion in Cushing's disease is under hypothalamic control whether or not a pituitary tumor is present. Moreover, there are observations that suggest that brain centers superior to the hypophysiotropic area of the hypothalamus are involved in the pathophysiology of Cushing's disease. This concept has led to the discovery of neurotropic drugs that are able to induce complete remission of Cushing's syndrome in a cerain percentage of patients. In some patients with severe psychiatric diseases, neuroendocrine abnormalities are present that resemble closely those characteristic for Cushing's disease. With the most refined neuroradiological methods, pituitary microadenomas are demonstrable in approximately 70% of patients with Cushing's disease, and this number compares well with those of earlier autopsy findings (70 to 80%). In a small number of patients (4 to 10%), these tumors are large and can easily be detected by standard roentgenograms of the head. Recent studies on the frequency of these large tumors do not support the hypothesis that adrenalectomy accelerates the progression of these tumors. In this case the term "Nelson's syndrome" would be uncessary. It is established that complete cure of Cushing's disease can be obtained in most patients with selective removal of a microadenoma from the pituitary gland. The current experience with this microsurgical procedure caused a renewed interest in Cushing's original suggestion that the disease is primarily a pituitary disorder. However, there are already a number of enigmatic observations. Possibly, the recent ultrastructural studies using immunocytochemical methods will resolve some of these problems. At this moment it is impossible to decide whether Cushing's disease is primarily a CNS or a pituitary disorder, when all arguments for one or the other hypothesis are taken into account... | 17 |
Effect of signal frequency and masker level on the frequency regions responsible for the overshoot effect. Two experiments investigated the relative influence of components close to and remote from the signal frequency (fs) on the overshoot effect. Overshoot was defined as the difference in threshold between a signal presented 4 ms after, and that for one presented 300 ms after, the onset of a 350-ms masker. Experiment 1 measured the overshoot effect using both wideband and narrow-band maskers (centered on fs), at two signal frequencies and three masker levels. Experiment 2 used a masker consisting of a "middle band" (MB, centered on fs) and two flanking bands (FBs, which, when combined with the MB, produced a flat wideband spectrum). The masker was continuous except for a 300-ms interval just prior to the signal, during which either all three bands, the MB alone, or the FBs alone were turned off. The results of both experiments showed that the overshoot effect was usually determined by off-frequency components. However, the on-frequency components played a substantial role when signal-to-noise ratios (SNRs) at threshold were unusually high, such as at fs = 6500 Hz and intermediate masker levels. It is suggested that two different mechanisms contribute to the overshoot effect: an off-frequency mechanism which operates at all fs and masker levels, and an on-frequency mechanism which contributes to the overshoot effect only at high-threshold SNRs. | 17 |
Islet transplantation in experimental diabetes of the rat. XIII. Cryopreservation reduces MHC class II but not class I antigens of rat pancreatic islets. Pretreatment of islet allografts prior to transplantation may reduce islet immunogenicity and prolong graft acceptance. We have studied the MHC antigen reducing effect of cryopreservation onto rat pancreatic islets performing indirect immunofluorescence tests and peroxidase-anti-peroxidase staining (PAP). Three different freezing programs were used. Program A: 0.5 degrees C/min to -35 degrees C and 1 degree C/min from -35 to -100 degrees C. Program B: 2 degrees C/min to -35 degrees C and 6 degrees C/min from -35 to -100 degrees C. Program C: 0.25 degrees C/min to -40 degrees C. Cryopreservation clearly reduced the number of class II antigen positive cells per islet in all cases. Program A was most effective with 45.5% of class II antigen negative islets compared to 6.4% of class II antigen negative fresh islets as shown by indirect immunofluorescence. The class II antigen reducing effect of cryopreservation proved to be permanent and not only temporary. Reduced class II antigen expression of cryopreserved islets could not be reestablished by incubation of the islets with rat IFN. A combination of cryopreservation followed by a 10 day culture period proved to be most effective with 85.6% of class II antigen negative islets. In contrast, we could not show any effect of cryopreservation on class I antigen expression. Viability of the cryopreserved rat islets was shown in-vitro by glucose stimulated insulin secretion. | 14 |
Discrimination learning alters the distribution of protein kinase C in the hippocampus of rats. Protein kinase C (PKC), an enzyme that plays an essential role in eukaryotic cell regulation (Nishizuka, 1988; Huang et al., 1989), is critical to memory storage processes both in the marine snail Hermissenda crassicornis and in the rabbit (Alkon et al., 1988; Bank et al., 1988; Olds et al., 1989). Specifically, activation of PKC mimics neurobiological correlates of classical conditioning in both Hermissenda and the rabbit, and the distribution of the enzyme within the rabbit hippocampus changes after Pavlovian conditioning. Here, we report that the amount of PKC, as assayed by specific binding of 3H-phorbol-12,13-dibutyrate (3H-PDBU), decreased significantly within the hippocampal CA3 cell region in rats trained to solve a water maze task either by cognitive mapping or by visual discrimination strategies, but not in control rats. Furthermore, hippocampal lesions interfered with acquisition of both of these tasks. We interpret these findings to support the conclusion that distributional changes of PKC within the mammalian hippocampus play a crucial role in memory storage processes. | 19 |
Functional control of chromogranin A and B concentrations in the body of the rat stomach. The chromogranins are soluble, acidic, proteins which are frequently co-stored in neuroendocrine cells with biogenic amines. In the gastric mucosa chromogranin A is localized to enterochromaffin-like cells which are the main source of histamine, and which are known to be regulated by circulating gastrin. We have used radioimmunoassays selective for the extreme C-terminal regions of chromogranin A and B to examine changes in gastric extracts following modulation of the gastric luminal contents. There were decreased concentrations of the two chromogranins in tissue extracts of rats after food withdrawal (which lowered plasma gastrin concentrations); inhibition of acid secretion with the H+/K(+)-ATPase inhibitor, omeprazole (which increased plasma gastrin concentrations) raised chromogranin A and B concentrations both in fasted rats, and in rats fed ad libitum. There was no evidence for altered patterns of posttranslational cleavage of chromogranin A or B with these treatments. The data indicate that chromogranin A and B concentrations in gastric ECL cells are regulated in parallel with histamine production, and are consistent with the idea that the chromogranins play a role in the formation and stabilization of the secretory granule involved in amine storage. | 21 |
[Freeze-fracture and deep etch replica of monkey ciliary muscle]. The author observed freeze fracture and deep etch replica of monkey ciliary muscle in order to study it's fine three dimensional structure. A three dimensional structure of the ciliary muscle cell and the relationship between the adjoining cells were elucidated. A lot of myofilaments which were meshy in shape were observed in the cytoplasm of ciliary muscle cells, and adhered to just beneath the cell membrane, nucleus membrane and limiting membrane of mitochondria directly. The arrangement direction of myofilaments was either parallel or oblique to the longitudinal axis of the cell, and then myofilaments formed dense bodies together with 10 nm filaments in some places. Myofilaments and 10 nm filaments also formed dense plaques together just beneath the cell membrane. Myofilaments and 10 nm filaments suggested to concern the cytoskeleton and the functional characteristics of the ciliary muscle cell. | 16 |
Comparison of amantadine and desipramine combined with psychotherapy for treatment of cocaine dependence. We conducted a single-blind, random assignment, placebo-controlled, 12-week comparison of desipramine hydrochloride and amantadine hydrochloride as adjunctive treatments to counseling for cocaine dependence. Subjects were 54 outpatients who met DSM III-R criteria for active cocaine dependence and who completed a minimum of 2 weeks of treatment. Subjects treated with fixed doses of 200 mg/day desipramine (N = 17), 400 mg/day amantadine-placebo (N = 16), and placebo (N = 21) did not differ for lifetime cocaine use, lifetime histories of psychopathology, admission scores on psychometric assessments, and sociodemographics. All treatment groups demonstrated dramatic and persistent decreases in cocaine use, craving for cocaine, and psychiatric symptoms consequent to treatment. Although there was a trend for more dropouts by subjects taking desipramine, there were no significant differences among treatment groups regarding retention in treatment, craving for cocaine, and decreased cocaine use confirmed by urine toxicology. There was a trend for subjects treated with desipramine to maintain longer periods of cocaine abstinence. Mean plasma concentration of desipramine in a subsample of our subjects was less than that recommended for treatment of depression, thus the dosage of desipramine may have been subtherapeutic. | 18 |
Long-term partial ureteral obstruction and its effects on kidney function. Previously it has been shown that partial ureteral obstruction present in young rats for 12 weeks results in small morphological changes in the kidney as well as slightly decreased kidney function. In the present study the aim was to examine whether rats obstructed for one year had more advanced changes in morphology and kidney function. The first group of animals examined after three weeks of obstruction showed only modest changes in kidney function with a reduced potassium concentration in the urine but no reduction in the glomerular filtration rate. After one year there was a reduction in urine flow as well as in the excretion of both potassium and sodium. Urine osmolality was also reduced. Glomerular filtration rate measured in this group of animals was reduced in the obstructed kidney by about 60% compared to the contralateral one. There were only small changes in the morphology with no loss in parenchymal weight or compensatory hypertrophy, but there was a significant deformation of the papilla and an increase in inflammatory cells in the parenchyma. In conclusion hydronephrosis during a shorter period is not harmful to kidney function but if sustained for an extended time period kidney function will deteriorate. | 15 |
DNA fingerprinting: parentage studies in natural populations and the importance of linkage analysis. It has been suggested that a full linkage analysis is a prerequisite for confident paternity testing, by using DNA fingerprinting, in natural populations. These fears are based on a confusion between linkage and linkage disequilibrium and a misplaced assumption that linkage between bands will necessarily reduce the effective number of paternal-specific bands. Several methods for detecting linkage without resorting to the analysis of large sibships are considered, for example, by analysing half-sibships, by band-association, and by altering the experimental conditions used. Even if linkage is present, the magnitude of its effects are unlikely to undermine the accuracy of the technique, given the average levels of variability being detected. We conclude that the effects of linkage are only likely to present a problem when sample sizes are very small or when closely related individuals are being tested together. | 19 |
Three genes for the human high affinity Fc receptor for IgG (Fc gamma RI) encode four distinct transcription products. Three distinct but closely related classes of receptors that bind the Fc portion of immunoglobulin G (Fc gamma RI, -II, and -III) have been identified in humans. Only Fc gamma RI has high affinity for ligand and has a unique third extracellular domain (EC3). We have characterized three genes for human Fc gamma RI (A, B, and C). Each gene consists of six exons, spans 9.4 kilobase pairs, and localizes to chromosome 1. Although they are remarkably similar, genes B and C are notably different from A; in-frame stop codons are present in the EC3 domain of genes B and C, and deletions occur in a splice donor sequence of gene B. Four distinct Fc gamma RI transcripts were analyzed. One transcript, from gene A, would encode a transmembrane receptor with three external domains. A second transcript, an alternatively spliced product of gene B, would encode a two-external domain transmembrane receptor. Two transcripts, from genes B and C, have stop codons in EC3 and would be predicted to generate secreted receptors. | 12 |
Increase in saccadic peak velocity with increased frequency of saccades in man. Twelve normal subjects (aged 22-80 yr, mean 47 yr) performed three blocks of 20 saccades made to LED targets stepped back and forth. The first and last blocks were performed at a (slow) rate of 0.18 Hz, while the middle block was performed at the faster rate of 1.15 Hz. Mean saccadic amplitude was unaffected by saccade rate, but latency and duration became shorter at the higher frequency. Most interestingly, the peak velocity increased by approx. 6% when saccades were performed at the higher rate. This increase was statistically significant, even after normalization for saccade amplitude. That saccadic frequency may affect saccadic peak velocity must be considered as a potential variable when analysing saccades. | 12 |
Efficacy of albendazole against inhibited early fourth stage larvae of Ostertagia ostertagi. Twelve untreated controls and 12 treated beef yearling steers were used in trials of albendazole (Smith Kline Animal Health Products) at 7.5 mg per kg (oral drench) against natural infections of inhibited fourth stage larvae of Ostertagia ostertagi. Albendazole had an efficacy of 83.8 per cent in removal of inhibited larvae. The mean number of inhibited larvae in untreated controls was 48.9 per cent. Efficacy against developing stages and adults of O ostertagi was 92.8 and 99.7 per cent, respectively. Efficacy against other worm genera in the abomasum, primarily thaemonchus and Cooperia adults, was 99.4 per cent. No signs of toxicity were observed following administration of albendazole. Some aspects of inhibition of O ostertagi in cattle in the USA are reviewed. | 13 |
[Morphogenesis of the chick embryo foot as studied by Janus green B-induced malformations]. Janus green was injected into the amniotic sac of 6-5-day-old chick embryos at a single dose of 8-5 or 15 mug; the dye causes respectively 55 and 82% malformations of the feet. Toe are affected by partial or total soft tissue syndactyly, hypophalangy and infrequently by hyperphalangy. Lateral toes are more severely and more frequently affected by syndactyly and hypophalangy than medium ones. Hyperphalangy is found exclusively in toes I and II and causes the formation of one excess phalanx at most. Syndactylous toes are joined by an overdeveloped digital membrane. Hypophalangic toes have a truncated (non-pointed) distal tip. Two phalanges are lacking at most. These malformations are due to two distinct phases of the Janus green action. The first one, which is early and fast, inhibits interdigital programmed cell death, causing in term the non-regression of the interdigital membranes and thus syndactyly. The second one, which is late and slow, blocks the apical growth; this leads to hypophalangy. | 11 |
Stress in air traffic personnel: low-density towers and flight service stations. Stress and anxiety levels were measured in 10 air traffic control specialists (ATCS) at two low traffic-density towers in Fayetteville (FYV), Ar, and Roswell (ROW), NM, and in 24 flight service (FS) specialists at those airports and at Okalhoma City (OKC), Ok. Physiological measurements consisted of heart rate and urine biochemical analysis for 17-ketogenic steroids, epinephrine, and norepinephrine. On-duty arousal in ATCSs and FS specialists was evident both physiologically and psychologically; such arousal was within psychologically normal limits and was generally low physiologically compared to other air traffic control (ATC) facilities studied in the past. Physiological stress levels at these low-density towers and flight service stations were also low compared to other ATC facilities studied previously. Therefore, it is inappropriate to describe all air traffic control work, as is commonly done in the popular press, as unusually stressful. Such accounts in the popular press tend to deal with the exceptional, rather than with the typical, controller or facility. | 19 |
Duroquinol as an electron donor for chloroplast electron transfer reactions. Duroquinol (tetramethylhydroquinone) was found to function as an electron donor in chloroplasts. Non-cyclic electron transfer from duroquinol to electron acceptors such as oxygen proceeded at high rates, was insensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) but was sensitive to the plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone (DBMIB). The electron transport from duroquinol was coupled to the synthesis of ATP. Spectroscopic studies of chloroplast electron carriers in the dark indicated the high-potential "Rieske" iron-sulfur center, cytochrome f, plastocyanin and P-700 were all reduced by duroquinol. The dark reduction of the "Rieske" iron-sulfur center and cytochrome f were inhibited by DBMIB but not by DCMU. These results have been interpreted in terms of a linear sequence of electron carriers in the non-cyclic electron transport chain which includes plastoquinone, the "Rieske" iron-sulfur center, cytochrome f, plastocyanin and P-700. | 17 |
Pre- and postweaning excretion of puberty-influencing chemosignals in house mice. Pre- and postweaning excretion of urinary chemosignals that influence puberty in female house mice were tested. The dependent variable used to assess the effectiveness of urine samples collected from donor mice was the age of first vaginal estrus in young female mice. Preweaning excretion of the puberty-delaying chemosignal by females was affected by litter sex composition; this effect interacted with the age of the young donor females. In litters of all females, the substance occurred from about the age of 9 days and in litters with 6 females and 2 males the delay substance was released from about the age of 17 days. Grouping dams during gestation but not prior to conception resulted in excretion of the puberty-delaying substance in the female progeny from the age of 17 days or possibly earlier. Young male mice do not excrete the puberty-accelerating chemosignal prior to the age of puberty. However, giving young males injections of testosterone resulted in an earlier first excretion of the acceleratory signal, suggesting that the machinery for chemosignal production is operative prior to the time of sexual maturity. Caging young males with an adult female prior to puberty resulted in earlier excretion of the puberty-accelerating substance, while caging young males with adult males retarded excretion of the substance. The findings are discussed in terms of early hormone effects on behavior and with regard to consequences for the chemosignal systems in house mice. | 17 |
[Resection of a mediastinal teratoma that perforated the lung and combined with aspergilloma in the tumor cyst]. We hereby report a rare case of a mature type teratoma that perforated the lung and combined with aspergilloma in the tumor cyst. The patient was a 48-year-old female, who complained of coughing and sputum. The chest roentogenography and chest CT suggested aspergilloma. The patient was operated upon. From the intraoperative and pathological findings, a mature type mediastinal teratoma was found to have perforated the bronchus and lung, and combined with aspergilloma in the cyst of the tumor. The tumor was resected, the drainage bronchus was closed. The mediastinal teratoma and aspergilloma have not recurred for two years and four months since the operation. | 12 |
The future of home health agencies. A multidisciplinary, multi-institutional, volunteer task force was convened by the Visiting Nurse Association (VNA) of Los Angeles to perform an evaluation of the agency and, on the basis of the evaluation, to make recommendations regarding the future potential of home health service agencies in the United States. For the VNA of Los Angeles, this use of a voluntary task force as a planning mechanism was successful; we strongly recommend its application to other agencies. The recommendations made were specific to the VNA of Los Angeles, but many are applicable to home health agencies in general. They called for an expansion of the types of services currently offered, with an emphasis on the coordinated team approach to health problems, an increased emphasis on preventive and health education services, and a movement toward providing services to groups as well as individual home care patients. The task force also urged willingness to expand services to include primary care. Modern management techniques were recommended as tools to increase the efficiency of home health service agencies. Potential new sources of revenue were proposed. | 16 |
Detection of human papillomaviruses in paraffin-embedded condylomata acuminata--comparison of immunohistochemistry, in situ hybridization, and polymerase chain reaction. The polymerase chain reaction (PCR) is used for detection of human papillomavirus (HPV) DNA in paraffin-embedded tissue sections of condylomata acuminata. Incorporation of biotinylated nucleotides during the amplification process allows a highly sensitive, fast, and non-isotopic detection of viral DNA in a subsequent Southern dot blot. In 100% (13 of 13) of histologically confirmed condylomata, HPV-6 or -11 could be detected by polymerase chain reaction. By in situ hybridization 77% (10 of 13) and by immunohistochemistry (IHC) 69% (nine of 13) positive results were obtained. Because HPV genital infection is linked to penile and cervical dysplasia, polymerase chain reaction provides a powerful and highly sensitive tool for epidemiologic studies on sexual transmission of HPV. | 18 |
Chronic interstitial nephropathy in patients on long-term lithium treatment. One-hundred and ten patients treated with lithium for more than six months were studied in order to determine the prevalence of lithium induced nephropathy. Eighteen of 69 patients (26 per cent) who had been treated for more than two years presented a chronic interstitial nephropathy characterized by a marked decrease in renal concentrating ability with a disproportionate preservation of glomerular filtration rate. Histologically, increased amounts of fibrotic tissue in the medulla and the cortex were found together with tubular atrophy. In 40 per cent of the patients who underwent renal biopsy, cystic formations in the cortex were found. The impairment of renal concentrating ability could be related to the duration of lithium treatment and the degree of tubular damage correlated with the degree of impairment of renal concentrating ability. Lithium induced, chronic nephropathy is a rather common complication of long-term lithium treatment and reduces the patients capacity to regulate water and electrolyte metabolism. As water and electrolyte loss appears to precede the slowly progressing lithium intoxication, the main hazard of lithium induced nephropathy is lithium intoxication. | 17 |
Cyclomaltodextrin glucanotransferase from Bacillus circulans E 192. I. Purification and characterization of the enzyme. The cyclomaltrodextrin glucanotransferase (CGTase) [1,4-alpha-D-glucan:4-alpha-D-(1,4-alpha-D-glucano)-transferase (cyclizing), EC 2.4.1.19] from Bacillus circulans E 192 has been purified to homogeneity by Cetavlon treatment, ammonium sulfate precipitation, DEAE Trisacryl M chromatography, Q Fast Flow chromatography, and affinity on beta-cyclodextrin-Sepharose 4B. Two isoenzymes were separated by FPLC on a Mono Q column. Their isoelectric points were estimated as 6.7 and 6.9 and they represented 13 and 87%, respectively, of the initial activity. Their molecular weight, pH, and temperature optima were estimated as 78,000, 5.5, and 60 degrees C, respectively. Kinetic parameters indicated that both enzymes had the same properties; they preferentially modified high-molecular-weight substrates to produce cyclodextrins. The apparent Vmax and Km values for soluble starch were 43 mumol of beta-cyclodextrin/min/mg of protein and 0.57% (w/v), respectively. Although this CGTase is not markedly thermostable, it is protected against heat denaturation by substrate, product, and/or calcium ions. The ratios of alpha-, beta-, and gamma-cyclodextrins produced have been determined as 1/7/2 in the initial phase of the reaction and 3/3/1 at equilibrium. | 15 |
Conal anatomy in aortic atresia, ventricular septal defect, and normally developed left ventricle. Although aortic valve atresia is usually associated with severe underdevelopment of the mitral apparatus and left ventricle in rare cases of aortic atresia, the left ventricle may be of normal size, or even enlarged. This occurrence seems related to the presence of a significant ventricular septal defect. We have presented the morphologic findings in seven patients with aortic atresia and normally developed left ventricle, (six necropsied patients, and one studied angiocardiographically). Four autopsied patients had conal type ventricular septal defects, characterized in three by conoventricular malalignment. Subaortic atresia in these patients resulted from leftward deviation of the conal septum. One patient with aortic atresia and well-developed left ventricle had a membranous defect, and one patient had a complete A-V canal. The ventricular septal defect in the patients with conoventricular malalignment are very similar to the conal VSD observed in patients with aortic arch interruptions. Although ultimate survival with these uncommon groupings of anomalies necessitates patency of the ductus arteriosus, clinical recognition rests on (1) awareness of its existence, (2) ultrasonography, and (3) selective biventricular and aortic angiography. It is possible that some of these patients might be candidates for ventriculo-aortic reconstitiution. | 17 |
Computerized electroencephalographic monitoring and selective shunting: influence on intraoperative administration of phenylephrine and myocardial infarction after general anesthesia for carotid endarterectomy. During carotid endarterectomy (CEA), phenylephrine infusions are commonly used to induce hypertension during carotid clamping in an attempt to increase collateral cerebral blood flow and prevent cerebral ischemia. Although this practice appears to increase the incidence of intraoperative myocardial ischemia during CEA when general anesthesia is employed, whether the limited use of phenylephrine infusions in specific instances of cerebral ischemia, as shown on an electro-encephalogram, results in low perioperative rates of both myocardial infarction (MI) and cerebral infarction remains unclear. We studied 171 CEAs done under general anesthesia performed with selective shunting based on the identification of cerebral ischemia by a two-channel computerized electroencephalographic monitor. The use of a phenylephrine infusion was restricted to the following instances of cerebral ischemia: 1) ischemia associated with hypotension that did not resolve within 2 minutes of decreases in anesthetic administration and treatment with fluid and/or colloid; 2) ischemia poorly or slowly responsive to shunt placement, accompanied by either hypo- or normotension; and 3) ischemia poorly or slowly responsive to removal of the carotid clamp, accompanied by either hypo- or normotension. Two non-Q wave MIs (1.2%) occurred, both nonfatal. There were two cerebral infarctions (1.2%) and three deaths not related to MI (1.8%). Based on these findings, in order to decrease the incidence of both MI and cerebral infarction after general anesthesia for CEA, we recommend the restrictive use of phenylephrine-induced hypertension for specific instances of slowly or poorly reversible cerebral ischemia, as shown on the electroencephalogram. | 25 |
Complete nucleotide sequence of segment 5 of epizootic haemorrhagic disease virus; the outer capsid protein VP5 is homologous to the VP5 protein of bluetongue virus. The complete nucleotide sequence of a cDNA clone representing the segment 5 RNA of epizootic haemorrhagic disease virus (EHDV) United States serotype 1 was determined. The 5' and 3' termini of the RNA are complementary and are capable of forming secondary structures. The comparison of the predicted amino acid sequence of the encoded outer capsid protein (VP5) with the sequences of VP5 from four serotypes of bluetongue virus, the prototype orbivirus, revealed that the protein shares 59% to 62% homologies with various BTV serotypes, including a single conserved glycine residue at the amino terminus. The sequence has been submitted to the Genebank databox (X55782). | 18 |
[Aeromonas spp. isolated from human feces. Species and pathogenicity factors]. The role of Aeromonas genus as a primary intestinal pathogen is still a matter of controversy. We have studied the isolation of Aeromonas spp. from human stools samples, looking for the production of pathogenic factors and its relationship with different species. From a total of 471 strains isolated, 241 were A. caviae, 127 A. sobria, 89 A. hydrophila and 14 non-typable strains. The pathogenic factors production was studied in a bacteria-free filtrate from a 18 hours trypticase-soy broth culture. Enterotoxin production was assessed by suckling-mice test, cytotoxin production by using Hela cells monolayer and hemolysin production by double dilution from the filtrate, plated in microdilution plates, against rabbit red-blood cells. Enterotoxin production test was positive for A. sobria, A. hydrophila and A. caviae in 81.1%, 62.9% and 7.0% of strains respectively. Cytotoxin production was also positive for these species in 96.6%, 76.4% and 4.1%, and hemolysin production was positive in 95.3%, 70.7% and 2.4% of the strains respectively. | 12 |
Implementations are not conceptualizations: revising the verb learning model. In a recent issue of this journal, Pinker and Prince (1988) and Lachter and Bever (1988) presented detailed critiques of Rumelhart and McClelland's (1986) connectionist model of the child's learning of the phonological form of the English past tense. In order to address these criticisms, a new connectionist model was constructed using the back-propagation algorithm, a larger input corpus, a fuller paradigm, and a new phonological representation. This new implementation successfully addressed the criticisms of the phonological representation used by Rumelhart and McClelland. It did a much better job of learning the past tense using a fuller input set with realistic frequencies of occurrence. Ancillary simulations using the same network were able to deal with the homonymy problem and the generation of forms like "ated" from "ate". The one feature not provided by the new model was a way of modeling early correct production of irregular forms. The success of the new model can be used to help clarify the extent to which the published critiques apply to a particular connectionist implementation as opposed to fundamental principles underlying the broader connectionist conceptualization. | 17 |
A unique fibrillar coat on the surface of migrating human primordial germ cells. Primordial germ cells (PGCs) were studied by electron microscopy in human embryos at 27 and 30 days of gestation. PGCs were mainly found in the hindgut epithelium, some at the stage of separation from the endoderm, and others in migration through the mesenchyme of the dorsal mesentery between the primitive intestinal wall and the coelomic epithelium, including the coelomic angle. A few PGCs were still located in the endodermal epithelium. Before the process of separation and migration, PGCs appeared clearly different from neighboring somatic cells (endodermal, mesenchymal and epithelial cells of the hindgut and the coelomic layer). PGCs located in the endodermal epithelium were large and showed an irregular cell body often provided with filopodia-like processes that contacted somatic cells to form small areas of focal junctions. As a rule, PGCs possessed a large, round nucleus containing one or two conspicuous nucleoli. Lipid droplets, abundant glycogen particles, ribosomes and mitochondria were often observed in their cytoplasm. A detailed ultrastructural analysis revealed a delicate fibrillar coat frequently present on the free surface of PGCs during their migratory phase through the mesenchyme of the dorsal mesentery. This surface coat, likely corresponding to a glycocalyx, appeared as a particular, conspicuous filamentous layer of 30 nm thickness, mainly in the leading pseudopodial projections of PGCs migrating toward their target. The surface coat of PGCs can be associated with the binding sites of specific macromolecular components of the extracellular matrix, including fibronectin, and hence plays a role in PGCs recognition and migration during this special embryonic phase.(ABSTRACT TRUNCATED AT 250 WORDS) | 17 |
Delta 9-tetrahydrocannabinol suppresses concanavalin A induced increase in cytoplasmic free calcium in mouse thymocytes. It has been shown that delta-9-tetrahydrocannabinol (THC) suppresses thymocyte, lymph node, and splenic lymphocyte proliferation in response to a mitogenic stimulus. It has also been reported that increases occur in the cytosolic free calcium concentration (Ca2+) in mitogen treated lymphocytes. In an attempt to understand a portion of the molecular basis of the THC induced suppression of lymphocyte proliferation, we have examined the effects of THC on the Concanavalin A (Con A) induced cytosolic free Ca2+ mobilization in mouse thymocytes measured by fluorescent Ca2+ probes and spectrofluorometry. The results show that a 10 minute pretreatment with THC suppresses the normal rise in intracellular free Ca2+ in response to Con A. A THC concentration of 4 micrograms/ml (13 microM) was suppressive and the drug vehicle, DMSO, had no effect. In addition, we found that THC pretreatment did not inhibit the binding of FITC labeled Con A to the thymocytes suggesting that the drug did not interfere with lectin binding to the cell surface. To further define the nature of the Ca2+ response affected by THC, mouse thymocytes containing fura-2 were exposed to Con A either in the presence or absence of Ca(2+)-containing medium. It was observed that THC abrogated both intracellular release (measured in Ca(2+)-free medium) as well as extracellular Ca2+ influx. These results suggest that a portion of the proliferation defect in THC treated lymphocytes may be related to a drug induced inhibition of Ca2+ mobilization that normally occurs following mitogen treatment. | 18 |
Delivery in an obstetric birth chair: a randomized controlled trial. To determine whether nulliparae whose second stage of labour is conducted in an obstetric birth chair have a lower incidence of instrumental delivery than those using a conventional delivery bed. Randomized controlled trial using sealed, opaque envelopes for allocation. Delivery ward in a busy teaching hospital. 1250 nulliparae with a singleton live fetus with cephalic presentation, without epidural anaesthesia, who had achieved full dilatation. Intention to conduct second and third stages of labour in either the Birth-EZ chair or the conventional delivery bed, as randomly allocated. Primary measure: vaginal operative delivery; principal secondary measures: duration of second stage, perineal trauma, blood loss, women's views, and neonatal status. Delivery in the birth chair did not result in a reduction in operative delivery, overall. However, there was a reduction in vaginal operative delivery for fetal heart rate abnormality. There was no beneficial effect on perineal trauma or puerperal perineal pain. Post-partum haemorrhage was more frequent in the birth chair group. Delivery in the birth chair does not offer any obvious advantage to women over delivery on a bed. | 14 |
Determination of proteolytic hydrolysis of thyroglobulin. A method for the determination of the free thyronine- and tyrosine-like amino acids in the thyroidal protein thyroglobulin is presented. The compounds of interest are monoiodotyrosine, diiodotyrosine, thyronine, diiodothyronine, triiodothyronine and tetraiodothyronine. The extent of proteolysis was followed by high-performance liquid chromatographic monitoring of both the remaining peptides and the formation of the free thyroidal amino acids. Total hydrolysis was achieved by a combination of proteolytic enzymes. A number of enzymes were tested, such as trypsin, chymotrypsin, pronase, aminopeptidase-M, carboxypeptidase-A, carboxypeptidase-P and carboxypeptidase-Y. The best combination turned out to be pronase followed by aminopeptidase-M. The relative amounts of the enzymes, with respect to the substrate thyroglobulin, and the time of incubation were optimized to achieve total proteolysis in 4 h. The method was applied successfully to samples from a toxicological experiment with sodium bromide. | 17 |
The role af amines in sexual activity of rats deprived of pineal gland. The studies were performed on rat's males 4--5 months of age in which pineal glands had been destroyed by electrocaogulation when they were 20--25 days old. These males, submitted to the action of both pCPA and DOPA had stronger reaction to these compounds than the shame operated animals. The administration of pCPA together with COPA was followed by the occurence of very high sexual activity which was accompanied by the decrease in the levels of 5-HT and 5-HIAA and the increase in DA level. DOPA together with Ro-4-4602 did not stimulate sexual behaviour although repeated administration resulted in the increase in DA level and the simulatneous decrease in 5-HT content. In these males, the observed increase in locomotor activity might be responsible for the reduced interest in females accompanying them. It seems that all the three amines play some role in sexual activity since the administration of compounds blocking respective receptors (pimozide-dopamine r., phentolamine-alpha-noradrenergic r., LSD 5-HT system antagonist) to males pretreated with DOPA and showing high sexual activity inhibited sexual activity. | 17 |
Cell growth and catecholase production for Polyporus versicolor in submerged culture. Cell growth and catecholase production for Polyporus veriscolor (ATCC 12679) were studied in mechanically agitated submerged culture, as functions of temperature. The exponential-phase growth rate exhibited a maximum at 28 degrees C. Over the range of 20 degrees C to approximately 30 degrees C, both cell mass and enzyme yield factors were constant. At higher temperatures (30 to 40 degrees C) cell mass yield factor decreased and enzyme yield factor increased. Specific respiration rate of P. versicolor was determined. Thermal deactivation of catecholase was investigated between 30 and 50 degrees C, and deactivation rates were fit to an Arrhenius rate expression. | 14 |
Intrinsic tryptophan fluorescence of Schizosaccharomyces pombe mitochondrial F1-ATPase. A powerful probe for phosphate and nucleotide interactions. Mitochondrial F1 from the yeast Schizosaccharomyces pombe, in contrast to the mammalian enzyme, exhibits a characteristic intrinsic tryptophan fluorescence with a maximal excitation at 291 nm and a maximal emission at 332 nm. Low values of Stern-Volmer quenching constants, 4.0 M-1 or 1.8 M-1, respectively, in the presence of either acrylamide or iodide, indicate that tryptophans are mainly buried inside the native enzyme. Upon subunit dissociation and unfolding by 6 M guanidine hydrochloride (Gdn.HCl), the maximal emission is shifted to 354 nm, a value very similar to that obtained with N-acetyltryptophanamide, a solute-tryptophan model compound. The tryptophan content of each isolated subunit has been estimated by fluorescence titration in the presence of Gdn.HCl with free tryptophan as a standard. Two tryptophans and one tryptophan are found respectively in the alpha and epsilon subunits, whereas none is detected in the beta, gamma, and delta subunits. These subunit contents are consistent with the total of seven tryptophans estimated for native F1 with alpha 3 beta 3 gamma 1 delta 1 epsilon 1 stoichiometry. The maximal emission of the isolated epsilon subunit is markedly blue-shifted to 310-312 nm by interaction with the isolated delta subunit, which suggests that the epsilon subunit tryptophan might be a very minor contributor to the native F1 fluorescence measured at 332 nm. This fluorescence is very sensitive to phosphate, which produces a marked blue shift indicative of tryptophans in a more hydrophobic environment. On the other hand, ADP and ATP quench the maximal emission at 332 nm, lower tryptophan accessibility to acrylamide, and reveal tryptophan heterogeneity. | 19 |
Intramammary challenge with Escherichia coli following immunization with a curli-producing Escherichia coli. Holstein and Jersey cattle were immunized with a curli-producing strain of Escherichia coli (pCRL65/A012) or a noncurli-producing strain (pUC18/HB101) to determine differences in resistance to establishment of experimental intramammary infection. Cows (n = 6 per group) were immunized at 14 d prior to drying off, 7 d of involution, and at calving with 3 x 10(10) E. coli in Freund's Incomplete Adjuvant. At 30 d of lactation, one mammary quarter of each cow was infused with a wild strain of E. coli (727). Escherichia coli 727 was isolated from a naturally occurring intramammary infection and produced curli. All challenged quarters became infected, and all cows developed acute clinical mastitis. Geometric mean duration of intramammary infections was 6 d for both immunization groups. All infections were spontaneously eliminated within 10 d. No differences occurred between immunization groups in blood selenium and glutathione peroxidase activity, plasma selenium, number of E. coli 727 isolated from secretion after challenge, rectal temperature and SCC response, clinical status of mammary quarters, or DMI. Reduction in milk production after challenge was greater for cows immunized with E. coli pCRL65/A012. Immunization of dairy cattle with a curli-producing strain of E. coli did not protect against experimental intramammary challenge during lactation. | 17 |
Circadian time dependence of erythropoietic and respiratory responses of Indian garden lizard, Calotes versicolor, to mammalian urinary erythropoietin and thyroxine. The circadian stage-dependent effects of mammalian urinary erythropoietin (Ep) and thyroxine (T4) on tissue energy metabolism (in vivo and in vitro) and erythropoiesis were examined in the Indian garden lizard. Both T4 and Ep increased erythropoiesis and also affected hepatic and muscle energy metabolism. Although both treatments increased circulating RBC count, irrespective of the timing of the treatment, the maximum erythropoietic stimulation was achieved only in the late photophase (9 hr after light onset, HALO). Hepatic oxygen uptake was significantly elevated at 3 and 9 HALO following in vivo Ep administration and 3, 9, and 15 HALO following in vivo T4 injection. In contrast, in vitro addition of either Ep or T4 to hepatic homogenates of untreated lizards significantly elevated respiratory rate, irrespective of the time of tissue collection. The rate of muscle tissue respiration was statistically elevated when Ep was administered in vivo at 9 and 15 HALO. The oxygen uptake was stimulated by T4 only at 15 HALO. While in vitro addition of Ep to tissue homogenates significantly depressed the respiratory rate of muscle collected at 3 HALO, addition of T4 stimulated oxygen uptake by the muscle tissue collected at 9 and 15 HALO. It is concluded that the effectiveness of Ep or T4 largely depends upon the phase of the organism's circadian system(s). | 18 |
Platelet survival studies in stroke-prone spontaneously hypertensive rats (SHRSP). Platelet survival was studied by using 51Cr-labeled platelets in stroke-prone spontaneously hypertensive rats (SHRSP), stroke-resistant SHR (SHRSR) and normotensive control rats of the Wistar-Kyoto (WK) strain. Relatively young animals of the same age prior to the development of cerebrovascular lesions (cerebral infarction and/or hemorrhage) were used. Platelet half-life time in SHRSP was slightly but significantly shorter than in any other groups or rats, irrespective of the type of platelet donors. Mean platelet consumption was also significantly increased in SHRSP only. Platelets of SHRSP injected into SHRSR showed normal survival. These data support the concept that the shortened platelet survival in SHRSP is brought about by some extracorpuscular abnormalities. Although the vascular changes in SHRSP could be the most likely explanation for the shortened platelet survival, its mechanism remains to be solved. This investigation suggests that studies of the platelet survival in hypertension may be useful in predicting the development of stroke before its clinical recognition. | 15 |
des-(1-3)-IGF-I, an insulin-like growth factor analog used to mimic a potential IGF-II autocrine loop, promotes the differentiation of human colon-carcinoma cells. HT29-D4 human colon-carcinoma cells have been shown to secrete insulin-like growth factor (IGF)-II and to simultaneously express type-I IGF receptors. However, the sequestration of IGF-II by several molecular forms of IGF-binding proteins (IGFBP) in the culture medium prevents the establishment of an operative IGF-II autocrine loop. IGFBPs secreted by HT29-D4 cells (HT29-D4 IGFBP) comprise isoforms of IGFBP-4 (25, 27 and 30 kDa) and 2 unidentified forms (34.5 and 32-34 kDa). This latter does not bind 125I-IGF-I. The net affinity of HT29-D4 IGFBP is about 12 times stronger for IGF-II (KD approx. 10(-10) M) than for IGF-I. All the HT29-D4 IGFBP molecular forms are unable to bind the N-terminally truncated IGF-I analog, des-(1-3)-IGF-I. In contrast, HT29-D4 cell-surface type-I IGF receptors bind IGF-I and des-(1-3)-IGF-I identically (KD approx. 5 x 10(-10) M). We have taken advantage of these particular binding properties to use des-(1-3)-IGF-I to mimic a potential IGF autocrine loop and to observe its biological consequences. Nanomolar concentrations of des-(1-3)-IGF-I induce HT29-D4 cells to develop into a differentiated phenotype, as judged by a substantial carcinoembryonic antigen release and the induction of numerous intercellular cysts with well-organized microvilli. In the same way, des-(1-3)-IGF-I early induces a slight inhibition of HT29-D4 cell proliferation. Based on these findings, we conclude that the type-I IGF receptor primarily controls the differentiation of these colonic cells, and that HT29-D4 cancer cells remain in an undifferentiated state because of their inability to use endogenous IGF-II as an autocrine regulatory factor. | 14 |
A neurolinguistic model for the study of aphasia. After having briefly discussed some of the most important models that are now used to understand or to classify the aphasic troubles, the authors explain the neurolinguistic model they are actually using to study some aspects of aphasics' verbal and nonverbal behavior. This theoretical model distinguishes proper linguistic from extralinguistic disturbances in the various clinical forms of aphasia. The existence in aphasia of extralinguistic components that might, in some way, influence verbal performances, is accepted by most authors. Much less obvious is the existence, at least in some clinical forms of aphasia, of proper linguistic (competence) disturbances. Our theoretical model assumes that in most clinical forms of aphasia some impairment of the semantic (lexical) structures of language exists, and it maintains that this trouble can be found both at the expressive and at the receptive level, both in verbal and in nonverbal tasks. Th results of some experimental investigations which give some support to this theoretical model, are briefly discussed. | 17 |
Effects of systemic and intra-amygdaloid diazepam on long-term habituation of acoustic startle in rats. Two experiments were conducted to examine the effects of the anxiolytic drug, diazepam, on long-term habituation of the acoustic startle response. The experiments were based upon the hypothesis that manipulations that reduce fear should enhance long-term response decrements by reducing a fear-like sensitization process. In Experiment 1 rats given intraperitoneal injections of 0.5, 1.2, or 2.5 mg/kg showed larger decrements of startle amplitude than vehicle-injected controls both over trials within sessions and over days. In Experiment 2 rats injected with 35 micrograms of diazepam bilaterally into the amygdala showed larger decrements of startle amplitudes over days than vehicle-injected controls. No within-session startle effects were detected in Experiment 2. Freezing behavior was measured in Experiment 2 as an index of fear, and the amygdala injections of diazepam retarded the development of fear in the startle chamber. This index of fear was not possible in Experiment 1 because of the sedating effects of systemic diazepam. We conclude that diazepam, acting at least in part through the amygdala, attenuates the fear-like sensitization process associated with the acoustic startle stimulus. By attenuating sensitization diazepam produces larger than normal reductions in startle amplitudes over trials and days without significantly affecting initial responsiveness. | 17 |
[Precancerous conditions of the prostate]. Carcinoma in situ, dysplasia, prostatic intra-epithelial neoplasia, duct-acinar dysplasia and large-acinar hyperplasia are various terms describing more or less identical forms of prostatic epithelial atypia. The precancerous nature of these lesions can be demonstrated by: morphological and functional similarities with carcinoma, a younger age than that of carcinoma, a higher incidence in cancerous prostates, an identical zonal distribution and a significant progression of high-grade lesions towards carcinoma. These hypoechoic lesions can be detected or monitored by transrectal ultrasonography. They also secrete PSA at levels intermediate between those of benign prostate and adenocarcinoma. Because of the occasional risk of malignant transformation and a frequent association with carcinoma, these lesions should be regularly monitored by digital rectal examination, PSA assays and possibly by ultrasound-guided biopsies. | 19 |
Purification of Drosophila hsp 83 and immunoelectron microscopic localization. Heat-shock protein (hsp) 83 was purified from Drosophila culture cells. Analysis by gel filtration revealed that this hsp exists in a dimeric form under nondenaturing conditions. Monoclonal and polyclonal antibodies produced against this hsp have been used to determine its intracellular localization by indirect immunofluorescence and immunogold electron microscopy in normal cells, after heat shock, during recovery and after a second heat shock. Under normal conditions, hsp 83 is predominantly cytoplasmic. Immunogold labeling reveals that this hsp is associated with vacuole-like structures containing numerous dense bodies. In addition, hsp 83 is detected, albeit at a lower level, in the nucleus where it is found within the network of perichromatin ribonucleoprotein (RNP) fibrils. This distribution changes during heat shock: hsp 83 is then found in increased concentrations at the cell periphery close to the plasma membrane. After a recovery period, hsp 83 appears associated with the nuclear membrane and/or with the neighboring endoplasmic reticulum. Following a second heat shock at 37 degrees C after recovery, a renewed deposition of hsp 83 is observed at the cell periphery. A small population of cells also shows an increased concentration of this protein in the nucleus. This intracellular distribution of hsp 83 is consistent with its reported association with various cellular proteins and suggest that this hsp may be involved in their intracellular transport and/or in the modulation of their activity. | 16 |
Effect of prednisolone treatment on selected respiratory parameters and cardiac output in prematurely delivered neonatal lambs. Lambs were delivered by hysterotomy on days 142 and 143 postcoitum and were assigned to either a control group or a prednisolone-treated group (10 mg/kg daily for four days). On days 1 through 3 of life erythrocyte 2,3-diphosphoglycerate values were significantly increased in the treated group. Prednisolone treatment did not result in significantly increased P50 values. Mean plasma corticoid values in the control group decreased gradually postpartum. The prednisolone-treated lambs compared to the control lambs had depressed corticoid values, differing significantly on day 4. Body weight gains were significantly depressed by treatment and this effect lasted beyond the treatment period. On day 1 of life (24 hours postinitial treatment) oxygen consumption and cardiac output were significantly elevated in the treated group. | 14 |
Group psychology and the structural theory: a revised psychoanalytic model of group psychology. It has been my aim in this paper to revise the existing psychoanalytic theory of group psychology in accordance with current structural concepts. The need for fundamental revision in the existing theory of group organization is demonstrated by its restriction to an oedipal paradigm, which cannot account for the regression to an oral paradigm of group organization during group formation. Freud's explanation of regression in crowds is reviewed. The limitations inherent in Freud's topographic and narcisistic models are demonstrated; irreconcilable contradictions are shown to exist between the two theories. A structural model of group psychology that is free from internal contradictions and provides a unifying explanation for both regression and merging in the crowd is developed. As a consequence of these revisions it is possible to conceptualize preoedipal organizations of group structure in addition to the oedipal paradigm proposed by Freud. | 18 |
Common sequence determinants of the response of a prokaryotic promoter to DNA bending and supercoiling. Inhibiting the activity of DNA gyrase by mutation or by drugs in S. typhimurium causes the loss of transcription attenuation in the histidine operon. We show that gyrase activity is needed to maintain high-level expression of the tRNA(His) gene (hisR), a prerequisite for proper functioning of the attenuation mechanism. A point mutation in the promoter of the tRNA gene cluster which includes the hisR gene, specifically relieves the promoter response to negative supercoiling thereby restoring full hisR transcription (and, in turn, his attenuation) in the presence of a defective gyrase. The very same mutation, a single base-pair substitution between the -10 box and the transcription start site (-7), was found independently among suppressors of the transcriptional deficiency caused by disruption of DNA curvature upstream from the hisR promoter. We show that the -7 change does not lead to a generalized increase of promoter strength; the effects of the mutation are seen only when gyrase is inhibited or the upstream curvature is altered. This suggests that the upstream curvature intervenes in the same initiation step which is sensitive to superhelical tension. Three additional promoter mutations correcting (or alleviating) the effects of the upstream alteration (including a change at -8) are described and discussed. | 19 |
Solubility of long-chain fatty acids in phosphate buffer at pH 7.4. The solubility of the saturated fatty acids lauric, myristic, palmitic, and stearic acid and the unsaturated oleic acid at 37 degrees C in phosphate buffer (pH 7.4) was estimated by using two independent methods. The one was a conventional solubility technique measuring the concentration of dissolved fatty acid in buffer by using radioactive compounds. The other was a dialysis exchange technique monitoring possible aggregation of solvated fatty acid anions by measuring the rate of diffusion of labelled compound across a dialysis membrane under conditions of chemical equilibrium. It was found that the results were strongly dependent on the radiochemical purity of the fatty acids. Using highly purified samples of radioactively labelled fatty acids, the solubility of monomeric laurate was shown to be greater than 500 microM, whereas the solubility of monomeric myristate was found to be 20-30 microM. Palmitate, stearate, and oleate solutions, on the other hand, showed a tendency to aggregation even at concentrations below 1 microM. Special attention was given to palmitate, as a reference compound for long-chain fatty acids, and the solubility of monomeric palmitate was estimated to be lower than 10(-10) M. | 18 |
Dentin- and enamel-bonding agents. The introduction of bonding agents in restorative dentistry has made it possible to adhere restorative materials to tooth structure. Since bonded restorations were introduced by Buonocore in 1955, extensive research has been conducted to develop systems that bond equally effectively to enamel and dentin. Researchers have identified a micromechanical retention mechanism for the attachment of hydrophobic resin restorative materials to both enamel and dentin that works if appropriate conditioning or priming steps are applied. At the dentin site, the modes of action of current adhesive systems converge to create a resin-dentin interdiffusion zone between the deep dentin structures and the filling material. To incorporate or remove the smear layer in this interdiffusion zone, different adhesion strategies are followed to obtain a resin-dentin bond. In the clinical situation, these modern dentin-bonding systems are more technique sensitive; the thickness of the interface, its elastic capacity, the polymerization efficiency and initiation of the bonding agent, and, finally, the application technique used for the restorative material play an important role in the final result. | 19 |
Human sickle hemoglobin in transgenic mice. DNA molecules that contain the human alpha- and beta s-globin genes inserted downstream of erythroid-specific, deoxyribonuclease I super-hypersensitive sites were coinjected into fertilized mouse eggs and a transgenic mouse line was established that synthesizes human sickle hemoglobin (Hb S). These animals were bred to beta-thalassemic mice to reduce endogenous mouse globin levels. When erythrocytes from these mice were deoxygenated, greater than 90 percent of the cells displayed the same characteristic sickled shapes as erythrocytes from humans with sickle cell disease. Compared to controls the mice have decreased hematocrits, elevated reticulocyte counts, lower hemoglobin concentrations, and splenomegaly, which are all indications of the anemia associated with human sickle cell disease. | 17 |
Single dose imipenem-cilastatin compared with three doses of cefuroxime and metronidazole as prophylaxis in elective colorectal surgery: a prospective randomized study. A prospective randomized study was performed with 61 patients undergoing elective surgery for colorectal cancer, to evaluate the prophylactic effect of two different parenteral antibiotic regimens. All patients were randomly allocated into two groups, comparable in age, sex, nutritional status and operative procedures. The patients in Group A (n. 31) received 1 g i.v. of imipenem-cilastatin at induction of anesthesia. Patients in Group B (n. 30) were given cefuroxime (1.5 g i.v.) plus metronidazole (0.5 g i.v.) at the time of anesthesia and two other administrations of the combined antibiotics (cefuroxime 0.75 g plus metronidazole 0.5 g i.v.) every 8 hours. The severity of sepsis was evaluated according to the scoring system proposed by Elebute and Stoner. No significant differences were found in terms of the rate of surgical infections: 9% in Group A and 16% in Group B. Infections not of surgical origin were found only in Group B (10.4%). These data suggest that a single dose of intravenous imipenem-cilastatin appears to be as effective as three doses of cefuroxime and metronidazole as prophylaxis against infection in elective colorectal surgery. | 14 |
Influence of dietary factors on the renal renin-angiotensin system. Protein meals and infusion of amino acids cause an increase of glomerular filtration rate in humans and animals with normal renal function despite the circulating renin concentration remaining unchanged. The renal hemodynamic response is not altered by angiotensin converting enzyme inhibitors, but it is obliterated by cyclooxygenase inhibitors. By contrast, chronic exposure to high protein diets raises circulating renin and increases messenger RNA of renin (but not of angiotensinogen) in kidney tissue. Chronically high protein intake raises the glomerular filtration rate and reduces glomerular permselectivity; the reverse is seen with low protein intake. In patients with renal failure, acute amino acid infusion or protein meals cause a paradoxical drop in glomerular filtration rate which is not influenced by converting enzyme inhibitors. | 17 |
Assay of reducing end-groups in oligosaccharide homologues with 2,2'-bicinchoninate. For the first time, reducing values of homologous series of oligosaccharides have been determined by the 2,2'-bicinchoninate assay. The extent of Cu2+ reduction was monitored by spectrophotometric measurement of Cu+/2,2'-bicinchoninate complexes. Conditions of the assay were optimized so that relatively uniform reducing values were obtained with oligosaccharides derived from starch, polygalacturonic acid, and chitin, regardless of degree of polymerization. The uniform values resulted because members of each oligosaccharide series were oxidized to similar levels beyond the aldonic acid stage, while oxidation was limited to the reducing-terminal residue. This conclusion was based on direct measurements of quantitative loss of paramagnetic copper (Cu2+) by electron paramagnetic resonance spectroscopy. | 19 |
Multihormonal response to dexamethasone. A study in atopic dermatitis and normal controls. Although minor disturbances of the circadian serum cortisol rhythm and diminished excretion of steroid metabolites have been reported in patients with atopic dermatitis, test assays regarding subtle neuroendocrine alterations have not been employed so far. We therefore studied the serum concentrations of cortisol, prolactin and adrenocorticotropin under baseline conditions, after 1 mg dexamethasone and after a defined methylprednisolone treatment in 15 patients with atopic dermatitis, in comparison with 10 healthy controls. The assessment of the hormones revealed no remarkable differences between either group at any of the blood sampling time points. However, in 3 patients and 2 control subjects, though exhibiting no concomitant disease, we could find no suppression of endogenous cortisol to below 5 micrograms/dl after oral intake of 1 mg dexamethasone. These cortisol non-suppressors showed lower dexamethasone serum concentrations in the morning after its administration, as compared with the suppressors. Acute (1 mg dexamethasone) or prolonged (40 mg methylprednisolone over 6 days) intake of glucocorticoids suppressed prolactin levels in both groups, demonstrating that the effect of glucocorticoids on the hormone system is not restricted to the hypothalamic-pituitary-adrenal axis. Our results indicate an intact feedback response of this hormonal axis to 1 mg dexamethasone and the ability of long-term as well as acute glucocorticoid administration to influence the prolactin secretion in patients with atopic dermatitis. | 19 |
Brain-death criteria currently used by pediatric intensivists. A survey was done to identify how pediatric intensivists determine brain death in children. Forty-nine pediatric intensive-care units (PICUs) were surveyed. The questionnaire explored the following areas: 1) clinical and confirmatory studies performed, 2) types of physicians involved, and 3) reevaluation intervals. Thirty-four centers responded to the questionnaire. Sixty-nine percent were children's hospitals, and 94% were university affiliates. The mean number of PICU beds was 17, with a mean admission rate of 890 patients per year, and the mean mortality rate for these units was 6%. There was general agreement on the sufficiency of clinical examination to determine cortical and brain-stem function. All the pediatric intensivists noted that a positive apnea test, absent cephalic reflexes, fixed and dilated pupils, and no motor response to pain were reliable signs of brain death. Radionuclide cerebral-flow scan and EEG were the confirmatory tests routinely used. Most physicians (77%) felt a second clinical examination was required within 12 to 24 hours. The opinion of more than one physician, one of whom was a neurospecialist, was required in 80% of the surveyed institutions. | 13 |
The transport of L-cysteinesulfinate in rat liver mitochondria. 1. The mechanism of L-cysteinesulfinate permeation into rat liver mitochondria has been investigated. 2. Mitochondria do not swell in ammonium or potassium salts of L-cysteinesulfinate in all the conditions tested, including the presence of valinomycin and/or carbonylcyanide p-trifluoromethoxyphenylhydrazone. 3. The activation of malate oxidation by L-cysteinesulfinate is abolished by aminooxyacetate, an inhibitor of the intramitochondrial aspartate aminotransferase, it is not inhibited by high concentrations of carbonylcyanide p-trifluoromethoxyphenylhydrazone (in contrast to the oxidation of malate plus glutamate) and it is decreased on lowering the pH of the medium. 4. All the aspartate formed during the oxidation of malate plus L-cysteinesulfinate is exported into the extramitochondrial space. 5. Homocysteinesulfinate, cysteate and homocysteate, which are all good substrates of the mitochondrial aspartate aminotransferase, are unable to activate the oxidation of malate. Homocysteinesulfinate and homocysteate have no inhibitory effect on the L-cysteinesulfinate-induced respiration, whereas cysteate inhibits it competitively with respect to L-cysteinesulfinate. 6. In contrast to D-aspartate, D-cysteinesulfinate and D-glutamate, L-aspartate inhibits the oxidation of malate plus L-cysteinesulfinate in a competitive way with respect to L-cysteinesulfinate. Vice versa, L-cysteinesulfinate inhibits the influx of L-aspartate. 7. Externally added L-cysteinesulfinate elicits efflux of intramitochondrial L-aspartate or L-glutamate. The cysteinesulfinate analogues homocysteinesulfinate, cysteate and homocysteate and the D-stereoisomers of cysteinesulfinate, aspartate and glutamate do not cause a significant release of internal glutamate or aspartate, indicating a high degree of specificity of the exchange reactions. External L-cysteinesulfinate does not cause efflux of intramitochondrial Pi, malate, malonate, citrate, oxoglutarate, pyruvate or ADP. The L-cysteinesulfinate-aspartate and L-cysteinesulfinate-glutamate exchanges are inhibited by glisoxepide and by known substrates of the glutamate-aspartate carrier. 8. The exchange between external L-cysteinesulfinate and intramitochondrial glutamate is accompanied by translocation of protons across the mitochondrial membrane in the same direction as glutamate. The L-cysteinesulfinate-aspartate exchange, on the other hand, is not accompanied by H+ translocation. 9. The ratios delta H+/delta glutamate, delta L-cysteinesulfinate/delta glutamate and delta L-cysteinesulfinate/delta aspartate are close to unity. 10. It is concluded that L-cysteinesulfinate is transported by the glutamate-aspartate carrier of rat liver mitochondria. The present data suggest that the dissociated form of L-cysteinesulfinate exchanges with H+-compensated glutamate or with negatively charged aspartate. | 14 |
Selective expression of RAG-2 in chicken B cells undergoing immunoglobulin gene conversion. Chickens create their immunoglobulin (Ig) repertoires during B cell development in the bursa of Fabricius by intrachromosomal gene conversion. Recent evidence has suggested that Ig gene conversion may involve cis-acting DNA elements related to those involved in V(D)J recombination. Therefore, we have examined the potential role of the V(D)J recombination activating genes, RAG-1 and RAG-2, in regulating chicken Ig gene conversion. In contrast to the coexpression of RAG-1 and RAG-2 observed in mammalian B cells that undergo V(D)J recombination, chicken B cells isolated from the bursa of Fabricius express high levels of the RAG-2 mRNA but do not express RAG-1 mRNA. The developmental and phenotypic characteristics of the bursal lymphocytes and chicken B cell lines that express RAG-2 mRNA demonstrate that selective RAG-2 expression occurs specifically in B cells undergoing Ig diversification by gene conversion. These data suggest that RAG-2 plays a fundamental role in Ig-specific gene conversion. | 17 |
The organization of the antero-posterior axis. The components specifying the spatial coordinates of the Drosophila embryo are deposited in the egg during oogenesis. Three maternal pathways control the pattern of the embryo along its antero-posterior axis. Genetic and molecular analysis has identified the key-genes in each of these pathways: (1) the bicoid gene encodes an anterior signal in the embryo that directs head and thorax formation via transcriptional activation of anteriorly expressed zygotic genes. (2) A posterior signal, the nanos gene product, antagonizes an inhibitor of abdominal development, hunchback, by translational regulation. (3) A terminal signal controls development at both poles of the embryo. It is probably induced by the somatic follicle cells and transmitted to the embryo via a membrane bound receptor encoded by the gene torso. Other maternal genes function in the localization of these signals or in signal transduction. | 14 |
Free fatty acids inducing mouse lethal toxicity in lipid extracts of Engraulis japonica, the Japanese anchovy. Mouse lethal toxicity was detected in the ether extract of Engraulis japonica (anchovy). The mouse toxicity of extracts was more potent from viscera than from other organs. Okadaic acid (C44H68O13) and dinophysistoxin (C45H70O13), lipophilic toxins derived from phytoplankton, which are usually considered to be the diarrhetic shellfish toxins, were not detected in the ether extract of ancovy. There occurred, however, two prominent peaks in high-performance liquid chromatography, which were identified as free eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The mouse toxicity observed correlated with the intensity of these two peaks. Toxicity was reduced considerably by pretreatment with Na2CO3. By quantitating EPA toxicity, it was concluded that the toxicity was not due to EPA only but also to DHA. The results indicate that substances in Japanese anchovy associated with mouse lethal toxicity include free polyunsaturated fatty acids, mainly EPA and DHA. | 15 |
DNA hybridization as a guide to phylogeny: chemical and physical limits. The technique of forming interspecific DNA heteroduplexes and estimating phylogenetic distances from the depression in their duplex melting temperature has several physical and chemical constraints. These constraints determine the maximum phylogenetic distance that may be estimated by this technique and the most appropriate method of analyzing that distance. Melting curves of self-renatured single copy primate DNAs reveal the presence of components absent from the renaturation products of exactly paired sequences. This observation, which confirms existing literature, challenges a fundamental assumption: that orthologous (i.e., corresponding) DNA sequences in the divergent species are being compared in DNA heteroduplex melting experiments. As a model system, the thermal stabilities of heteroduplexes formed between a human alpha-globin cDNA and four alpha-like globin genes isolated from chimpanzee are qualitatively compared. The results of this comparison show that the cross-hybrids of imperfectly matched gene duplicates from divergent species can contribute to the additional components that are present in renatured single copy DNAs. Single copy DNA, as usually defined, includes sequence duplicates that will obscure phylogenetic comparisons in a mass hybridization of genomes. | 19 |
Analysis of adenoid cystic carcinoma treated by radiotherapy. The records of 41 patients with adenoid cystic carcinoma of the head and neck region who had been treated with radiotherapy were reviewed. Local control was achieved in 72.3% in the cases with primary lesions at 5 years. The prognosis for tumors that arose in the major salivary glands was better than that for tumors that arose in the minor salivary glands; however, the difference was not statistically significant. In the minor salivary glands, early-stage tumors were well controlled with the use of radiation therapy alone. In spite of the high local control rate, the disease-free survival rate of the patients at 10 years was only 20.8%. Lung metastasis determined the prognosis. | 12 |
Immunological profile of patients with non-cirrhotic portal fibrosis. The aetiopathogenesis of non-cirrhotic portal fibrosis (NCPF), a common cause of portal hypertension in India, is not known. To study the immune status of NCPF patients and to see whether immunological mechanisms have a role to play, humoral and cell-mediated immunological studies were carried out in 43 patients with NCPF and compared with equal number of matched healthy controls and 31 patients with compensated liver cirrhosis. Serum immunoglobulin A (IgA) and complement (C3, C4) levels were significantly (P less than 0.001) lower in NCPF patients compared with controls and cirrhotics. There was no significant difference between the total or the relative concentration of the immunoglobulins and complements between NCPF patients and healthy controls, but, in patients with cirrhosis, concentration of all the immunoglobulins was higher. The cutaneous response to dinitrochlorobenzene was poorer in patients with NCPF, but the difference between cirrhotics and controls was not significant. A decrease in the suppressor/cytotoxic (T8) phenotype of lymphocytes in the peripheral blood and an increase in the ratio of helper/inducer (T4) and T8 lymphocytes was seen in patients with NCPF and cirrhosis. Although these results indicate definite immunological abnormalities in NCPF patients, their role in the pathogenesis of NCPF remains to be investigated. | 18 |
[Alcohol and atherogenesis: effect of low and high doses of ethanol on rat blood cholesterol]. Alterations in content of cholesterol and specific radio-activity of erythrocyte lipoproteins were studied in rats after administration of labelled sterol under conditions of acute and chronic influence of low 0.6 g/kg and high 4.0 g/kg doses of ethanol. Both these doses caused a decrease in content of high density lipoproteins (HDL) after single ethanol administration, while content of apoB containing lipoproteins as well as binding of labelled sterol with erythrocytes were elevated after long-term ethanol treatment. Atherogenicity index was increased after single and chronic administration of either low or high doses of ethanol. In chronic administration of low doses of ethanol specific radioactivity of HDL was decreased, thus suggesting that cholesterol acceptor function of these particles was lowered. | 19 |
Comparison of several G-tolerance measuring methods at various seatback angles. The most commonly accepted endpoint indicative of impending "blackout" for subjects (Ss) exposed to +GZ on a centrifuge is peripheral light loss (PLL). A comparison was made using PLL and cessation of bloodflow in the temporal artery, as measured in eight Ss with an externally mounted ultrasonic flowmeter using the doppler effect. Each relaxed S was exposed to increasing G (onset rates of 0.1 and 0.3 G/s), while positioned at seatback angles of 15 degrees, 60 degrees, and 75 degrees. In addition to the flowmeter, arterial oxygen saturation was monitored with an ear oximeter, and respiration and ECG were recorded. Tolerance to G loads was slightly greater with the more rapid rate of G onset. While use of the flowmeter resulted in obtaining reliable G tolerance endpoints in all cases, in only about 75% of these cases was the same true for PLL. Responses obtained from the ear oximeter were variable and delayed, showing only slight decreases in arterial saturation, which became more pronounced as the G-load exposure duration increased. | 16 |
Fasting-induced rise in locomotor activity in rats coincides with increased protein utilization. The aim of this study was to investigate the possible relation between the modifications in locomotor activity (on running wheel) which occur during prolonged fasting and changes in the utilization of energy reserves. In 18-week-old rats, we found that the rate of body mass loss reflects the changes in nitrogen excretion that occur over three phases of fasting: (I) initially decreasing, (II) maintained at a low level and (III) increasing. Locomotor activity started to increase during phase II without a change in its nycthemeral pattern. By contrast, the 10-fold higher daily locomotor activity that occurred in phase III was marked by a higher proportion of diurnal activity. Using 9-, 18-, and 33-week-old rats, in order to obtain a different timing in the metabolic changes during fasting, we could confirm the coincidence between the later rise in locomotor activity and the occurrence of phase III. Refeeding of rats of either age in phase III rapidly suppressed fasting-induced changes in locomotor activity. These data accord with the idea that behavioral changes reflecting the search for food are triggered by a later and reversible change in the utilization of body protein vs. lipid stores during prolonged fasting. | 17 |
[Preoperative staging and recurrence of rectal tumors. Comparison of transrectal ultrasonography and magnetic resonance]. The accuracy of transrectal US (TRUS) and of MRI was evaluated in the preoperative staging and in local recurrences of rectal cancers. Fifty-four patients were examined: 45, with known rectal cancer, for preoperative staging, and 9 for the evaluation of local recurrences. Nineteen patients were examined with MRI in basal conditions, 21 after rectal air enema and 5 after paramagnetic contrast enema (Gd-DTPA). The following parameters were evaluated for preoperative staging: wall infiltration, invasion of perirectal fat and adjacent structures, lymph node involvement. Morphologic and signal intensity (on MRI) changes were evaluated for the diagnosis of local recurrences. TRUS provided 2 false positives. In the same patients, basal MRI results were poor, owing to difficult demonstration of the different wall layers, while in the patients studied after air enema, the lesion was hyperintense. In 20 patients with a fat-infiltrating tumor, TRUS provided 3 false negatives and 2 false positives; basal MRI yielded poor results, while air enema and paramagnetic contrast enema clearly demonstrated all fat-infiltrating lesions, with only one false positive. | 15 |
Effect of the number and depth of embryos transferred and unilateral or bilateral transfer in tubal embryo transfer (TET). Our purpose was to evaluate the possible effects of the number of embryos transferred, the depth of embryos placed within the tube(s), and unilateral or bilateral tubal transfer on pregnancy initiation in tubal embryo transfer (TET). One hundred eight consecutive TET cycles were analyzed. Oocyte retrievals were carried out by transvaginal ultrasound-guided aspiration of follicles. Forty-eight hours after oocyte retrieval, the developing embryos at the stage of two to four cells were transferred into the fallopian tube(s) by laparoscopy. A maximum of four embryos was transferred to each patient. The pregnancy rates were similar among the cycles in which two, three, or four embryos were transferred. In addition, there was no significant difference in the pregnancy rate whether the embryos were deposited > 4 cm or between 3 and 4 cm into the tube(s). Although the pregnancy rate was greater in cycles of bilateral tubal transfer, the difference from that of unilateral transfers was not significant. Our data indicate that when two to four embryos were transferred and the embryos were placed > or = 3 cm within the tube(s), unilateral or bilateral tubal transfer had little influence on the ultimate success of TET. | 14 |
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