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9451449 | Analysis of long-range structural effects induced by DNase-I interaction with actin monomeric form or complexed to CapZ. | Two fundamental properties of monomeric actin were examined in this study, ie its interaction with DNase-I, and the inhibition of endonuclease activity consecutive to the association of the two molecules. In particular, the topological independence between catalytic site of DNase-I and interface with actin, structural changes in actin monomer and the absence of conformational changes in DNase-I were described. We demonstrated a loss of flexibility of antigenic structures in actin subdomain I (ie epitopes 18-28 and 95-105) as well as modification in the exposure of Cys10 and Cys374 after DNase-I binding. Furthermore, the conformational changes induced by DNase-I into the actin molecule weakened the interaction of CapZ to its binding site located in the C-terminal region of actin monomer. These structural changes were time-dependent. When actin was cleaved in the DNase-I binding loop (sequence 38-52) at position 42 by E coli A2 strain protease, a tight DNase-I binding to split actin and the conformational changes were still observed, whereas the DNase-I inhibition activity pletely abolished. Finally, when we substitute Ca2+ by Mg2+ (ATP-Mg2+ monomeric actin) which induces a tighter conformation of actin and partially restores the inhibitory ability of split actin, long-range conformational effects of DNase-I are prevented and the plex DNase-I-actin-CapZ is obtained. |
9451451 | Surface activity properties of cysteine-substituted C-terminal melittin analogues. | In order to extend our knowledge of factors important in the surface activity of melittin, cysteine was substituted for lysine-21 and lysine-21/glutamine-25 in a pair of synthetic peptide analogues. The first of these changes resulted in only modest effects on secondary structure (determined in 50% trifluoroethanol), emulsification and surface tension properties. Introduction of a second cysteine greatly reduced both the rate of surface tension decay and the equilibrium surface tension attained, although secondary structure (determined in 50% trifluoroethanol) was only slightly affected by this modification. This latter pletely lacked emulsification and haemolytic properties and was found to oligomerise readily due to the formation of intermolecular, disulphide bridges. These results indicate that oligomerisation abolishes surface activity in melittin. |
9451450 | Identification of ribosomal protein S1 as a poly(A) binding protein in Escherichia coli. | To elucidate the metabolic function of mRNA polyadenylation in Escherichia coli. we searched for a polyadenylate-binding protein as a potential mediator of the function of the poly(A) moiety. Using a nitrocellulose filter-binding assay and a Northwestern blot technique, a protein in the ribosomal supernatant fraction of E coli was identified and purified to homogeneity. N-terminal sequence analysis yielded a 25-residue sequence which corresponded to the 25 N-terminal amino acids of protein S1, one of the proteins of the E coli 30S ribosomal subunit. Poly(A) binding to S1 protein was inhibited by Mg2+ and Mn2+ and by ATP and stimulated 8-fold by 100 mM KCl. The binding of S1 to poly(A) occurred with an association constant of 3 x 10(6) M-1 and seemed to be only mildly cooperative. Competition studies of the binding of poly(A) and poly(C) to purified S1 protein were consistent with the presence of two polynucleotide binding sites, of which one binds poly(A) five times more strongly than poly(C), whereas the other binds poly(C) 50 times more strongly than poly(A). Poly(A) bound to 30S ribosomal subunits but not to 50S ribosomes. To study possible association of S1 with the poly(A) tracts of E coli mRNA in the process of translation, poly(A) RNA was isolated from polysomes by oligo(dT) cellulose chromatography and the poly(A) RNA with bound protein was eluted either directly or after digestion with RNase T1 and A. When subjected to Western blot analysis with antibody to S1, both poly(A) RNA and isolated poly(A) tracts revealed bound S1 protein. The implications of these results for the possible interaction of poly(A) tracts of mRNA and the translational machinery of E coli are discussed. |
9451452 | Structure-activity relationships in the fusion of small unilamellar phosphatidylcholine vesicles induced by a model peptide. | Limited proteolysis of fatty acid-free bovine serum albumin by pepsin yields several well characterized peptides, one of which (P9, M(r) 9,000), induces fusion of small unilamellar vesicles (SUV) of phosphatidylcholine at pH 3.6. Circular dichroism (CD) of P9 solutions confirmed that the peptide undergoes a reversible transition between pH 7 and pH 3.6. The spectral changes observed with CD suggest that in the low pH conformation there is a decrease in the alpha-helical contents and an exposure of hydrophobic residues. CD and differential ultraviolet spectroscopy demonstrated that P9 binds to micelles of hexadecylphosphorylcholine and the binding produces changes in the tertiary structure of the peptide. Reduction and carboxymethylation of the two disulfide bridges of P9 produced loss of the ability to induce fusion of SUV, although the reduced peptide binds to vesicles, induces loss of entrapped marker and produces vesicle disruption. In the active form P9 exposes hydrophobic groups, one amphiphilic alpha-helix and requires the integrity of the disulfide bridge-stabilized tertiary structure. |
9451453 | Protein translocation functions of Escherichia coli SecY: in vitro characterization of cold-sensitive secY mutants. | Protein translocation across the plasma membrane of E coli is facilitated by Sec factors, including the membrane-embedded SecYEG subunit and the SecA ATPase. Although there plete agreement that SecA is essential for protein translocation, some publications question the essentialness of SecY. We previously isolated a number of cold-sensitive mutants of secY and characterized their in vivo phenotypes. In this study, we characterized membrane vesicles prepared from these mutants with respect to their in vitro activities to support protein translocation and to activate the SecA ATPase. These studies revealed several single amino acid alterations that abolish these in vitro activities of membrane vesicles. In particular, several mutations in the two most carboxy-terminal cytoplasmic domains of SecY prevented SecA from functioning as the translocation ATPase. A number of mutants showed strong correlations between in vivo protein export ability, in vitro translocation activity and in vitro translocation ATPase activity, substantiating the importance of SecY in vivo and in vitro. A few other mutants were affected in only one or two aspects of these properties, suggesting that they were differentially affected in some substeps of translocation. These results provide further evidence that SecY has vital roles in protein translocation, in which the 'motor' function of SecA and the 'channel' function of SecYEG should be coordinated. |
9451454 | Preparation of a 'beheaded' derivative of the 30S ribosomal subunit. | Oligodesoxyribonucleotide-directed cleavage of protein-deficient Thermus thermophilus derivatives of the 30S ribosomal subunits with RNase H is described. A homogeneous RNP fragment has been isolated as a result of the cleavage and subsequent purification in the sucrose gradient. It corresponds to the central and 5' domains of the 30S ribosomal subunit. The pactness of the fragment in solution suggests that it can be considered as a 'beheaded' derivative of the 30S ribosomal subunit. The absence of a reconstitution stage in isolation of the 22S RNP fragment provides for its preparation in large amounts. |
9451455 | Regulation of protein synthesis by minigene expression. | Peptidyl-tRNA hydrolase (Pth), an enzyme essential for Escherichia coli viability, scavenges peptidyl-tRNA released during abortive polypeptide chain elongation. Bacterial strains of E coli partially defective in Pth activity are unable to maintain bacteriophage lambda growth. Phage mutations that e the bacterial defect have been located to several regions in the lambda genome named bar. Plasmid constructs expressing just the bar region are toxic and cause a general arrest of protein synthesis in Pth-defective cells. Inspection of the nucleotide sequence from two bar regions reveals the short coding sequence AUG AUA Stop, spaced by an AT-rich segment from a Shine Dalgarno-like sequence (S-D). These sequences have been named minigenes. Base changes altering the putative S-D, the two sense codons, or the stop codon have been found to reduce Bar-toxicity. Transcripts containing bar function as mRNA. Upon expression in pth mutants, wild-type (bar+) transcripts are found associated with ribosomes. In addition, bar+ RNA forms plexes with the 30S ribosomal subunit and the initiator tRNA and can be released upon run-off translation in the same way as an authentic mRNA. A cell free system for protein synthesis reproduces the in vivo effects: bar+ expression inhibits protein synthesis, bar+ RNA sequences are associated with ribosomes in the inhibited extracts, addition of purified Pth restores synthesis, and excess of tRNA(Lys), specific for the last sense codon in a mutant toxic minigene, prevents protein synthesis inhibition. Also, bar expression promotes association of methionine with ribosomes possibly in a plex. These results are consistent with a model proposing tRNA starvation to explain the behaviour of a pth mutant, thermosensitive for protein synthesis. |
9451456 | Evaluation of the presence of porcine reproductive and respiratory syndrome virus in packaged pig meat using virus isolation and polymerase chain reaction (PCR) method. | An investigation was carried out to assess the potential presence of porcine reproductive and respiratory syndrome virus (PRRSV) in packaged pig meat. Samples of meat were collected at the processing plants and were sent to the laboratory for testing by virus isolation and reverse transcription-polymerase chain reaction (RT-PCR). Samples collected at four plants were randomly selected from lots of packaged pig meat from different slaughtering days and were sent frozen to the laboratory. Homogenates of meat were prepared and were inoculated onto MARC-145 cells and after two passages the presence of PRRSV was monitored by indirect immunofluorescence staining using PRRSV specific monoclonal antibody. All pig meat samples (six pools of meat samples from 73 different lots = 438 total homogenates) tested were found negative by virus isolation. Primers from open reading frames 6 and 7 were designed and a RT-PCR assay was developed and was demonstrated to detect both North American and European PRRSV isolates. Using this assay virus was detected at a concentration as low as 0.355 infectious virions per ml in supernatant of PRRSV infected cells. This RT-PCR assay could detect PRRS viral nucleic acid from various tissue samples of experimentally infected pigs including muscle tissue, thus demonstrating its applicability on tissue samples. All meat sample homogenates tested by RT-PCR (one sample pool from the 73 lots) were also found negative for PRRS viral nucleic acid. The results suggest that pig meat does not retain detectable amounts of PRRSV and further support that the transmission of PRRSV through pig meat is unlikely. |
9451457 | Cytotoxic T-lymphocyte responses in cattle infected with bovine viral diarrhea virus. | A system for a reproducible in vitro restimulation of bovine viral diarrhea virus (BVDV)-specific cytotoxic T-cells (CTL) was developed. Lymphocyte cultures of BVDV-immunised cattle were stimulated with infectious BVDV isolate PT810 and binant bovine interleukin-2 for 12 to 25 days. A specific lysis of Concanavalin A-stimulated BVDV-infected autologous target cells was observed, whereas allogeneic BVDV-infected target cells were only marginally lysed as detected by flow cytometry. BVDV-specific lymphocyte transformation was further characterised by the expression of bovine lymphocyte activation antigens and bovine MHC class-II molecules. Secondary stimulation of CTL was influenced by in vitro production of BVDV-specific neutralising antibodies, which were secreted exclusively in BVDV-inoculated lymphocyte cultures of immunised cattle. These results demonstrate the presence of CTL in peripheral blood mononuclear cells (PBMC) of immunised cattle which can kill autologous BVDV-infected antigen-presenting cells after in vitro restimulation. |
9451458 | Detection and identification of avian mycoplasmas by polymerase chain reaction and restriction fragment length polymorphism assay. | The polymerase chain reaction (PCR) with plementary to the 16S rRNA genes was used to detect avian mycoplasmas. A primer pair designed for the detection of human and rodent mycoplasmal species was examined for its ability to detect the most important avian mycoplasmas. After testing the respective reference strains, we found that Mycoplasma iowae, Mycoplasma meleagridis and Mycoplasma synoviae could be detected by PCR with this primer pair, and distinction could be made among them by restriction fragment length polymorphism (RFLP) assay with two restriction enzymes (BamHI and RsaI). For the detection of Mycoplasma gallisepticum by PCR, we needed species-specific primers. The results of the PCR- and RFLP, based identification procedures of 17 different field isolates agreed with those obtained by conventional methods. |
9451459 | Expression of functions by normal sheep alveolar macrophages and their alteration by interaction with Mycoplasma ovipneumoniae. | Normal sheep alveolar macrophages collected by bronchial lavage were exposed to live or heat-killed Mycoplasma ovipneumoniae organisms, and their capability to ingest Staphylococcus aureus and to elicit antibody-dependent cellular cytotoxicity against sensitized chicken red blood cells was tested. Controls consisted of non-infected macrophages in M199 medium. In addition, the effect of M. ovipneumoniae on expression of surface molecules on these sheep alveolar macrophages was determined. The percentage of S. aureus ingested by nontreated sheep alveolar macrophages was significantly higher than that of infected macrophages. Live mycoplasmas were more effective in suppressing the ingestion of S. aureus by these macrophages than killed mycoplasmas. Both live and killed mycoplasmas suppressed the cytolytic effect of the sheep alveolar macrophages to a similar degree. About 78% and 45% of the normal sheep alveolar macrophages had IgG plement receptors, respectively. Infection of these macrophages with M. ovipneumoniae decreased significantly the expression of IgG receptors but had no effects plement receptors. There were substantial increases in the expression of both MHC class I and class II by the mycoplasma-induced macrophages pared with unstimulated macrophages. Live mycoplasmas were more effective in inducing expression of both classes than killed mycoplasmas. The results, taken together, suggest that M. ovipneumoniae induced alterations in macrophage activities and this may be a contributing factor in the pathogenesis of respiratory disease induced by the organism. |
9451460 | Metabolic changes in red cells in response to adhesion of porcine K88 fimbriated Escherichia coli. | Red cells glycolytic enzymes attached and nonattached to K88+ Escherichia coli were assayed. Hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase and glutathione reductase activities, were measured. E. coli with K88ab fimbriae, E. coli with K88ac fimbriae, and isolated K88ab fimbriae were investigated for their effect on the above enzymes. Different changes were obtained with K88ab + pared with K88ac + bacteria. Purified fimbriae gave a third set of responses. |
9451461 | Virulence of Streptococcus suis type 2 for mice and pigs appeared host-specific. | A murine model for Streptococcus suis infection in pigs was validated by inoculating groups of 5 BALB/c and 5 CF1 mice with 10(7) CFU/ml of 13 different S. suis serotype 2 strains. The pathogenicity of these strains had been established in a standardized pig model of S. suis infection using one-week-old gnotobiotic pigs. We inoculated groups of mice intraperitoneally with 4 strains that were highly virulent for pigs and belonged to the phenotype MRP+EF+, with 4 strains, that were weakly virulent for pigs and belonged to the phenotype MRP+EF+, and with 5 strains that were non-virulent for pigs and belonged to phenotype MRP-EF-. The S. suis strains that were highly virulent for pigs caused high morbidity and an intermediate mortality in mice, the S. suis strains that were weakly virulent for pigs caused high morbidity but low mortality, and the strains that were non-virulent for pigs, induced highest morbidity and mortality. These results parable in both breeds of mice. In contrast to the pathology of S. suis infection in pigs with specific lesions, lesions in mice were histologically often characterized as non-specific, i.e., necrotizing encephalitis and focal or diffuse hepatitis sometimes with abscesses. Irrespective of breed (BALB/c vs. CF1), the murine model used for S. suis infection was patible with the pig model. This indicates that virulence of S. suis type 2 for mice and pigs is host-specific. Therefore, we regard the presently available murine models unsuitable for studying S. suis infections in pigs. |
9451462 | Specific identification of Campylobacter fetus by PCR targeting variable regions of the 16S rDNA. | Campylobacter fetus is recognized as a human and animal pathogen. The isolation and differentiation of C. fetus in diagnostic laboratories is hindered by its relatively slow growth and lack of distinguishing biochemical characteristics. We developed a fast, reliable PCR assay that specifically amplifies a 554-bp segment of the 16S rDNA from C. fetus. Fifty-two ATCC reference strains and 255 bacterial field prising the genera Campylobacter, Arcobacter, Helicobacter, Escherichia, Listeria, Salmonella, and Wolinella were evaluated using this PCR protocol. Only C. fetus strains were amplified. Sequence analysis of amplicons from ATCC and field strains of C. fetus confirmed the presence of the target DNA fragment. The detection limit of the technique was 5.9 x 10(3) CFU/ml. This PCR assay can yield reliable detection of C. fetus within 3 h after isolation of presumptive colonies on agar plates. |
9451463 | Mixed paramyxovirus infection of wild and domestic birds in Israel. | Five cases of dual isolations of different serotypes of avian paramyxoviruses (APMV) from domestic and wild birds are described: one case of mixed infection by APMV-1 and APMV-4 and four cases of infection by APMV-1 and APMV-2 serotypes. The double infection was proven by consecutive isolations of two viruses from allantoic fluid samples derived from single swabs after their respective treatment by antisera against each suspected virus. The finding of double APMV infection in poultry farms appears to be important for epizootiology and pathogenesis of APMV-caused diseases. |
9451464 | Prolonged persistence of Listeria monocytogenes after intragastric infection in corticosteroid-treated mice. | In an attempt to obtain a model more closely resembling natural listeriosis, we studied the course of infection in mice inoculated by the intragastric route with Listeria monocytogenes. Corticosteroid-treated, and untreated mice both developed subclinical infection without mortality, but faecal shedding and persistence of bacteria in the liver and spleen of corticosteroid-treated mice were significantly more protracted than in untreated mice. Untreated mice cleared the bacteria from their livers and spleens by day 5 postinfection (PI), whereas treated mice did not clear the organisms until 8-9 days PI. In untreated mice faecal shedding lasted 5 days PI, whereas in treated mice the organisms were recovered at significantly higher levels until day 9 PI. The only intestinal lesions observed were mild pyogranulomatous changes in the dome area of some Peyer's patches in treated mice. |
9451465 | Glibenclamide: an old drug with a novel mechanism of action? | This review is meant to give to the readers an overview of the pharmacokinetics, pharmacodynamics, mechanism(s) of action and therapeutical indications of the pound glibenclamide, which is a cardinal drug in the treatment of type 2 diabetes mellitus. Data produced in our own laboratory over the past 15 years will be presented, along with reference to the main literature in the field. As pharmacokinetics is concerned, special emphasis will be placed on the detrimental effect of hyperglycemia in the intestinal absorption of this class of drugs. Both beta-cell and extrapancreatic effects of glibenclamide will be highlighted. The mechanism of action of the drug consists in the inhibition of the ATP-sensitive K+ channels, which leads to depolarization of the cells and insulin secretion. Based on the same mechanism are also the extrapancreatic action of the drug at the liver, skeletal muscle, heart muscle and smooth muscle sites. The newly discovered possible physiological actions of the C-peptide molecule [suggesting a stimulatory effect of C-peptide on the Na+, K+ (ATPase) pump and on plications], cast a new light on all therapeutic approaches (like sulfonylurea class pounds and whole pancreas or islet of Langerhans transplantation), which induce/replace both insulin and C-peptide secretion. |
9451466 | Resistance training improves the metabolic profile in individuals with type 2 diabetes. | Aerobic endurance exercise has traditionally been advocated in the treatment of type 2 diabetes, while the potential role of resistance training has often been overlooked. The aim of the present study was to determine the effect of circuit-type resistance training on blood pressure, lipids and long-term glycaemic control (HbAlc) in type 2 diabetic subjects. Thirty-eight type 2 diabetic subjects were enrolled in the study; 18 participated in a 5-month individualized progressive resistance training programme (moderate intensity, high volume) twice a week, while the remaining 20 served as controls. The exercise group showed improvements in total cholesterol (6.0 +/- .3 vs 5.3 +/- .3 mM; P < 0.01), low density lipoprotein (LDL)-cholesterol (3.90 +/- .22 vs 3.35 +/- .21 mM; P < 0.01) and triglycerides (1.91 +/- .25 vs 1.53 +/- .22 mM; P < 0.01). Also, the difference in the change in HbAlc between the groups (0.5%) achieved statistical significance (P < 0.01). Circuit-type resistance training seems to be feasible in moderately obese, sedentary type 2 diabetic subjects and the inclusion of circuit-type resistance training in exercise training programmes for type 2 diabetic subjects seems appropriate. |
9451467 | Leptin inhibition of insulin secretion from isolated human islets. | Leptin is a hormone produced and secreted from the adipose tissue. Its physiological actions include the regulation of satiety, food intake and energy balance. The production of leptin is increased by high insulin levels. Here, we demonstrate that leptin acts as an inhibitor of glucose-induced (20 mM) insulin secretion from isolated human islets. No effect was observed in the presence of lower glucose levels (2.8 and 10 mM glucose). The pancreatic beta-cell might represent a target of a direct physiological action of leptin. We suggest the presence of an "adipo-insular axis" in which leptin mediates negative feedback from the adipose tissue to the endocrine pancreas. |
9451468 | Attenuated neutrophil respiratory burst following acute hypoglycaemia in diabetic patients and normal subjects. | The effects of insulin-induced hypoglycaemia on the neutrophil respiratory burst were investigated in six patients with type 1 diabetes and six non-diabetic control subjects. Plasma glucose reached similar nadirs in control subjects (0.9 +/- 0.1 mmol 1(-1); mean +/- SEM) and diabetic patients (1.2 +/- 0.2 mmol 1(-1)) (NS). The resting neutrophil respiratory burst was similar in control subjects (1.26 +/- 0.15 mV) and diabetic patients (1.03 +/- 0.18 mV) (NS). The neutrophil respiratory burst fell following hypoglycaemia in control subjects and diabetic patients to 0.38 +/- 0.05 mV (P < 0.001) and 0.54 +/- 0.09 mV (P < 0.05), respectively. This fall was significantly greater in control subjects (ANOVA; P < 0.001). Resting neutrophil counts were not significantly different in control subjects (3.2 +/- 0.3 x 10(9) 1(-1)) and diabetic patients (6.1 +/- 1.5 x 10(9) 1(-1)). Following hypoglycaemia, neutrophil numbers increased in control subjects and diabetic patients to 11.5 +/- 1.4 x 10(9) 1(-1) (P < 0.01) and 9.7 +/- 1.7 x 10(9) 1(-1) (P < 0.05), respectively. This increase was significantly greater in control subjects (ANOVA; P < 0.001). These results suggest that the neutrophil respiratory burst is suppressed in response to hypoglycaemia and that this phenomenon is more pronounced in non-diabetic subjects. |
9451469 | Insulin resistance, a result of reduced synthesis of prostaglandylinositol cyclic phosphate, a mediator of insulin action? Regulation of cyclic PIP synthetase activity by oral antidiabetic and antihypertensive drugs. | Reduced ability or failure to stimulate cyclic adenosinemonophosphate (AMP) synthesis on a second addition of hormone 30 min after a first stimulation was taken as an indirect indication of the synthesis of the cyclic AMP antagonist prostaglandylinositol cyclic phosphate (cyclic PIP). In diabetic rats, because of an increased possibility of restimulating cyclic AMP synthesis, the formation of cyclic PIP should be reduced. Additionally, severalfold increased basal cyclic AMP synthesis can be observed in diabetic hepatocytes parison with controls. Upon measuring cyclic PIP levels after hormonal stimulation in all organs of diabetic rats, it was found that stimulation of cyclic PIP synthesis by insulin decreased gradually in a time-dependent manner. Plasma membranes were prepared from diabetic Ksj db/db mice and from spontaneously hypertensive rats (SHR), and in a subsequent assay for cyclic PIP synthetase, an up to 60% decrease of enzyme activity was found. Cyclic PIP synthetase can pletely inhibited by preincubation with protein kinase A. It is most likely that this serine phosphorylation reaction by which the enzyme is inhibited also in vivo is a result of increased cyclic AMP levels. The addition of 10(-5)-10(-4) M sulfonylureas to the enzyme assay of liver plasma membrane causes full inhibition, and the addition of 10(-5)-10(-4) M biguanides, a two- to fourfold activation of the enzyme. Activation of cyclic PIP synthetase by biguanides can also be demonstrated in intact cells. It is a fast reaction and additive with respect to the activation by fluoride or guanylyl-imidodiphosphate (GMP-PNP), and it is most likely the effect with which the biguanides produce the correcting changes in metabolism. Furthermore, antihypertensive drugs like captopril, guanethidine, and dihydralazine also activate cyclic PIP synthetase. In contrast to the activation by the biguanides, this effect is not additive to the activation by fluoride. It appears that essential hypertension and type 2 diabetes are connected with or may be the result of a reduction in synthesis of the intracellular messenger cyclic PIP, whose synthesis is stimulated by hormones like insulin and noradrenaline (alpha-adrenergic action). |
9451470 | Glycation of insulin results in reduced biological activity in mice. | Bovine insulin was glycated by in vitro incubation with 20-220 mM D-glucose for 1-48 h. The percentage of glycation was dependent on time, glucose concentration, temperature and pH, attaining values up to 28%. Glucose-lowering activities of glycated and control (non-glycated) insulin preparations were assessed in mice by intraperitoneal injection in a 39% (w/v) glucose solution (2 g/kg body weight) at doses of 0.05 and 0.25 units/kg body weight. Injection of glucose alone significantly (P < 0.001) increased plasma glucose concentrations at 30 min. Simultaneous administration of non-glycated insulin with glucose significantly decreased the 30-min glycaemic excursion (P < 0.001) in a dose-dependent manner. Glycated insulin exhibited a significant reduction (P < 0.001) in glucose-lowering activity under these conditions. The relationship between the extent of insulin glycation and glucose-lowering activity at 0.25 units/kg was assessed using five different insulin preparations glycated between 6%-28%. The insulin-induced decrease in plasma glucose at 30 min was inversely related to the extent of glycation (r = 0.99). Glycated insulin (10(-8) and 10(-6) M) also exhibited a significantly reduced (P < 0.05) ability to stimulate glucose oxidation in isolated mouse diaphragm pared with non-glycated insulin. These data indicate that glycated insulin exhibits impaired biological activity which may contribute to glucose intolerance in diabetes. Further studies are required to determine if glycation of insulin occurs in man and if this process contributes to the pathogenesis of diabetes. |
9451471 | Increased CD5+CD19+ B lymphocytes at the onset of type 1 diabetes in children. | The aim of this study was to determine whether the proportion of circulating B cells expressing the differentiative antigen CD5 was increased in children affected by type 1 diabetes, and whether the number of these cells was correlated with the presence of anti-islet cell autoantibodies. Sixteen children affected by insulin-dependent diabetes mellitus (type 1) were investigated for the presence of B lymphocytes bearing the CD5 surface molecule, T-cell-specific activation markers, organ- and nonorgan-specific autoantibodies. The number of CD5+CD19+ cells was higher in type 1 children with a very recent onset of the disease, pared with patients on insulin therapy for more than 30 days and controls (P < 0.05). No correlation was found between the number of CD5+CD19+ cells and the presence of either organ- or nonorgan-specific autoantibodies. Our results indicate that CD5+CD19+ cells are involved in the pathogenesis of type 1 diabetes in children. A potential immunoregulatory role of this B cell population is discussed. |
9451472 | Association of diabetic retinopathy, ischemic heart disease, and albuminuria with diabetic treatment in type 2 diabetic patients. A population-based study. | The management of type 2 diabetes has been a controversial issue. The objective of the present study was to estimate patients' characteristics, particularly diabetes treatment, associated with retinopathy, coronary heart disease, and microalbuminuria in an unselected population of 532 type 2 diabetic individuals from munities. Questionnaires, clinic record review, and physical examination were used for the assessment of the three conditions. Fasting C-peptide was measured in all insulin-treated participants to establish type 2 diabetes. Patients with and without each of the plications were matched for age at diagnosis of diabetes and duration of diabetes. Univariate matched and multivariate conditional logistic regression analyses were used to estimate the independent association between each of the various factors studied and the plications. Insulin treatment was the only factor independently associated with all plications (odds ratios 3.3, 3.4, and 5.3 for diabetic retinopathy, coronary heart disease, and albuminuria, respectively). Glycosylated hemoglobin, uric acid, systolic blood pressure levels, and body mass index were also independently associated with at least one of plications but not with all of them. Although no cause-effect relationship can be established from this cross-sectional design, insulin therapy seems to be a marker of severer diabetes from the time of diagnosis. |
9451473 | Heritability of cardiovascular risk parameters in subjects with increased susceptibility to non-insulin-dependent diabetes mellitus. | To evaluate the inheritance of cardiovascular risk parameters in subjects with increased susceptibility for non-insulin-dependent diabetes mellitus, pared 25 pairs of healthy twins who were offspring of diabetic parents with 25 pairs without a parental history for type 2 diabetes mellitus (12 monozygotic and 13 dizygotic in each group). Environmental factors were also evaluated to avoid bias in the assessment of concordance. No significant difference was found in concordance between monozygotic and dizygotic twins for physical activity, diet, smoking, alcohol intake and living together or apart. Genetic analysis revealed a substantial heritability for weight, body mass index, percentage of body fat, lipoprotein(a), high density lipoprotein (HDL)- and HDL2-cholesterol, without significant differences between the two groups. We conclude that heritability of several cardiovascular risk parameters is not increased in subjects with increased susceptibility to type 2 diabetes mellitus. |
9451474 | Capillary and aortic endothelia interact in situ with nonenzymatically glycated albumin and develop specific alterations in early experimental diabetes. | Diabetic mice (6 weeks duration) were studied to assess the interaction of advanced glycation endproduct-modified albumin (AGE-Alb) with micro- and macrovascular endothelium, and to evaluate the alterations induced in the ultrastructure of the lung, kidney, and aorta. [125I]-AGE-Alb and AGE-Alb-Au were perfused in situ in the vasculature; the total uptake was quantitated by spectrometry, and the endothelial pathways of AGE-Alb-Au and the morphological alterations of the vascular beds were examined by electron microscopy. The results showed that [125I]-AGE-Alb (0.567 microM) was taken up specifically and saturably by all organs studied, and particularly by the lung. AGE-Alb-Au endocytosis and transcytosis occurred in the pulmonary and aortic endothelia, and were enhanced in diabetic animals. Also in diabetic animals, AGE-Alb-Au was detected throughout the kidney glomerular basement membrane (GBM) and within open filtration slits of podocytes, suggesting altered barrier function. The structural modifications progressed, and at the end of the experimental period, in the lung approximately 28% of the capillaries and approximately 25% of the alveoli pressed or even collapsed, due to the hyperplasia of extracellular matrix and interstitial connective tissue. The presence of adherent intravascular macrophages suggests the development of an inflammatory immune process. The structural modifications observed in kidney glomeruli included thickening (approximately 30%) of the GBM and the disappearance of diaphragms between the cellular processes of podocytes. The aortic endothelium displayed luminal foldings, increased number (2.8-fold) of Weibel-Palade bodies, and proliferation of basal lamina. Together, the results show that in diabetes there is enhanced vascular uptake of AGE-Alb and significant pathomorphological changes of micro- and macrovessels. |
9451475 | Pravastatin in diabetes-associated hypercholesterolemia. | Patients with diabetes mellitus (DM), type 1 and type 2, have an increased risk of coronary heart disease as a result of accelerated atherosclerosis. Dyslipidemia, often found in these patients, plays an important role in this process. This study investigates the efficacy and safety of lipid-lowering therapy with pravastatin, a 3-HMG-Coenzym A reductase inhibitor in hypercholesterolemic type-1 and type-2 diabetic patients. Of 49 patients (22 type-1 DM and 27 type-2 DM), 24 patients were treated with pravastatin, 20 mg/day, and 25 patients with placebo. After 24 weeks, total cholesterol (TC) was decreased by 22.2%, low-density lipoprotein (LDL) cholesterol by 25.8% and triglycerides (TG) by 13.6%. Pravastatin treatment did not induce a significant change in high-density (HDL) cholesterol levels. No differences in effects of pravastatin treatment on serum lipids and lipoproteins were found with respect to the diabetes type. No serious side effects occurred and pravastatin treatment did not cause any deterioration in glycemia control. The data suggest that pravastatin is effective and safe in the treatment of dyslipidemia in both type-1 and type-2 diabetic patients. |
9451476 | Glucose transporter isoform (GLUT) 2 expression in beta-cells of long-term syngeneic islet grafts. | Syngeneic islets were transplanted into the liver of streptozotocin (STZ)-induced diabetic LEW.1W rats, and the expression of the glucose transporter isoform GLUT 2, an ponent of the glucose-sensing mechanism of the pancreatic beta-cell, was determined in the grafted islet tissue. Graft-bearing liver was obtained 12, 36, and 60 weeks after transplantation, and tissue sections were immunoperoxidase stained for GLUT 2 and major islet peptides. Islet cell aggregates of different sizes were found in the portal tract and in juxtaposition to the hepatocytes. At all time points, beta-cells in the grafts displayed GLUT 2 parable to that of islets in nondiabetic rats. Islet cells containing immunoreactive insulin and islet amyloid polypeptide were plentiful, while those staining positive for glucagon and somatostatin were scarce in these grafts. The results show that beta-cells in islets engrafted in the liver, although initially exposed to chronic hyperglycemia, have the capability of stably expressing GLUT 2 over long-term periods. |
9451477 | The needs of Asians and Pacific Islanders living with HIV in New York City. | This article familiarizes the reader with AIDS among Asians and Pacific Islanders (A&PIs) in New York City. The first section describes the epidemiology of AIDS among A&PIs in the United States and in New York City. In the United States 4,131 A&PIs have been diagnosed with AIDS. The age at diagnosis in the United States has been relatively stable over the past decade, although the proportion of diagnoses represented by older A&PIs (aged 40 to 49) has been increasing in New York City. The proportion of heterosexual diagnoses have been relatively stable over the past 6 years, whereas other racial groups have shown increases in the proportion of heterosexual transmissions. Data on defining opportunistic infections suggest that a different clinical pattern exists among A&PIs pared with other racial groups diagnosed in New York City and the United States whereby A&PIs exhibit the highest proportion of Pneumocystis carinii pneumonia of all groups. The second section provides a discussion of some of the issues facing HIV positive A&PIs and their families in the process of accessing services munity-based HIV service organizations in New York City. One broad concept emerged from the client focus group that served to organize the analysis: pelling case for HIV service organizations to initiate, expand, and maintain family services, however family is defined. The location of A&PI AIDS service organizations and its implications for recentering families in the caregiving process is discussed. |
9451478 | Continued risky injection subsequent to syringe exchange use among injection drug users in New York City. | Although the vast majority of injection drug users (IDUs) attending syringe exchange programs in New York City have stopped risky injection (injecting with syringes used by someone else), there remains a subgroup of IDUs who continue to engage in high-risk injecting behaviors despite access to sterile syringes. Subjects were randomly recruited from five legally authorized syringe exchange programs in New York City between October 1992 and August 1994. Participants were asked about drug and sexual risk behavior 30 days prior to their first use of the syringe exchange as well as during the 30-day period prior to the interview while using the exchange. Of the 2,465 participants, 77.4% reported no risky injection during the 30 days prior to using syringes exchange. For this analysis we included only those who reported risky injection for the 30-day period prior to using syringe exchange (N = 556). pared sociodemographics and behavioral characteristics of a group who continued risky injection while using the syringe exchange, "continuers," N = 158 (28.8%) with a group who reported risky injection prior to using the exchange and then ceased risky injection while using the exchange, "stoppers," N = 391(71.2%). Continuers were significantly more likely to report passing on dirty syringes to social network members and to inject cocaine at least daily. We present other predictors of continued risk and discuss the implications for interventions and make mendations for syringe exchange programs. |
9451479 | Cocaine abuse counseling as HIV prevention. | The current study evaluated the efficacy of cocaine abuse counseling alone as a strategy to reduce HIV-related sexual risk behaviors. Participants were 232 cocaine-abusing or dependent individuals who received up to 26 weeks of Matrix counseling but no formal HIV-prevention interventions. One hundred fifty-seven (67.6%) pleted assessments at admission, during treatment, and at 6 months following admission. Participants located for follow-up were significantly more likely to be Caucasian, to be better educated, and plete longer treatment episodes than those not located. Main study findings indicated a statistically significant association between safer sex behavior pletion of a cocaine abuse counseling episode (chi 2 (2, n = 157) = 6.25, p < .05). Participants pleted counseling were more likely to change to safer sex or maintain safer sex over the 6-month period than participants who terminated counseling prematurely. The primary method for reducing sexual risk involved overall decreases in reported numbers of partners (Partners-baseline = 5.32, SD = 6.25; Partners6 Months = 2.47, SD = 2.62; F(1, 132) = 36.32, p < .001) among this group of mostly heterosexual (89.9%), Caucasian (69.0%), crack cocaine users (65.6%). We concluded that cocaine abuse counseling is a powerful intervention for reducing HIV-related sexual behaviors in this group at high risk for exposure to HIV. Study findings suggested that efforts to evaluate HIV prevention programs must also account for the effect of drug counseling. |
9451480 | The impact of multiple bereavement in a gay male sample. | The effect of experiencing multiple close losses on a variety of psychological symptoms was examined in a sample of HIV positive and HIV negative gay men over 1 year. Symptoms assessed included depression, intrusive and avoidant thoughts and images, anxiety, and general distress. It was found that on average, experiencing two or more losses in the year prior to the initial interview was associated with significantly higher levels of distress in follow-up assessment over 1 year. Comparisons between subjects with two or fewer losses versus three or more losses produced the largest differences in emotional symptoms. HIV positive subjects showed higher levels of distress symptoms on all measures, except for intrusive and avoidant thoughts and images. These findings indicate that the experience of multiple close losses, which is mon among HIV-infected gay men, chronically exacerbates their emotional distress. |
9451482 | The efficacy of the health belief model for predicting condom usage and risky sexual practices in university students. | This investigation examined the ability of the health belief model (HBM) to predict condom usage and risky sexual practices in 122 white heterosexual college students (ages 17 to 33 years). The HBM did not significantly explain condom usage in the 58 men and 64 women surveyed; rather it partially explained the variance in sexual risk behaviors. Results were not consistent for men and women. The ponents significantly explained 18% of the variance in multiple sexual partnerships in men and 22% of the variance in this behavior in women. The HBM constructs also explained 9% of the variance in the likelihood of women being intoxicated or high during sex and 18% of the variance in the number of sexual risk behaviors endorsed by women. These findings suggest that the HBM has differential and limited utility for predicting sexual practices in university students. Future research is needed to examine prehensive models of behavior change. |
9451481 | Structure and activities of agencies providing HIV and AIDS education and prevention to Latina /Latino communities. | Community agencies play an important role in HIV and AIDS education and prevention. On the other hand, important distinctions among these agencies many times go unrecognized by policy makers and program planners. The purpose of this study is to examine differences in the structure and activities of Latina/Latino and non-Latina/Latino agencies that both provide HIV and AIDS education and prevention services to munities. A total of 280 agencies in counties in four regions of California (the Los Angeles area, the Bay area, the Central Valley, and counties that fell outside these three regions) were surveyed regarding agency characteristics and type and extent of HIV and AIDS education and prevention activities. One hundred eighty-one surveys were returned, a return rate of 65%. Non-Latina/Latino agencies were larger, in terms of staff size, offered a wider range of services, and utilized more volunteer staff than Latina/Latino agencies. Latina/Latino agencies were smaller in size and had more bilingual staff than non-Latina/Latino agencies. Latina/Latino agencies utilized local Spanish-language media more than non-Latina/Latino agencies, and Latina/Latino agencies were more likely to have had their education and prevention activities reported on by local Spanish-language media than non-Latina/Latino agencies. Latina/Latino agencies were more likely than non-Latina/Latino agencies to educate and to show educational videos to one or two persons at a time. Non-Latina/Latino agencies were more likely to do education and prevention activities with migrant farm-workers. There was also an effect of geographic region on types of education and prevention activities. |
9451483 | Finding health and AIDS information in the mass media: an exploratory study among Chinese college students. | Western health officials believe the incidence of HIV infection in the People's Republic of China is much higher than has been reported, but knowledge about the disease remains low. This paper describes a preliminary study of Chinese college students' AIDS knowledge and beliefs and of the acceptability of mass media for AIDS education. Focus group interviews of 73 Xiamen University students showed that the students used radio more consistently than any other media and viewed magazines as the best media source of health information. However, they expressed a general distrust of the health information media offer. They possessed quite a bit of accurate information about AIDS but also harbored many inaccurate beliefs. Most felt that their personal risk from AIDS was very low because they felt distanced--either geographically or morally--from those at risk. Disturbing numbers felt that fate, not individual behavior, determines whether or not a person contracts HIV. The paper discusses the study's implications for future research. |
9451486 | [From the racemate to the eutomer: (S)-ketamine. Renaissance of a substance?]. | The pharmacological profile of ketamine: Until recently, clinically available ketamine was a racemic mixture containing equal amounts of two enantiomers, (S)- and (R)-ketamine. The pharmacological profile of racemic ketamine is characterized by the so called dissociative anesthetic state and profound sympathomimetic properties. Among the different sites of action, N-methyl-D-aspartate (NMDA)-receptor antagonism is considered to be the most important neuropharmacological mechanism of ketamine. Effects on opiate receptors, monoaminergic and cholinergic transmitters, and local anesthetic effects are obvious as well. Following intravenous administration, a rapid onset of action is seen within 1 min, lasting for about 10 min. The anaesthetic state is terminated due to redistribution, followed by hepatic and renal elimination with a half-life period of 2-3 h. For alternative administration, the intramuscular and oral route is also appropriate. The most important adverse effects are hallucinations and excessive increases in blood pressure and heart rate. These reactions can be attenuated or avoided bining of ketamine with sedative or hypnotic drugs like midazolam and/or propofol. During controlled ventilation, increases in intracranial pressure are unlikely to occur. The special pharmacological profile of (S)-ketamine: In general, the pharmacological properties of (S)-ketamine parable to the pound. On the different sites of action, parable effects were found, but significant quantitative differences also became obvious. pared with (R)-ketamine and the racmic mixture, the analgesic and anesthetic potency of (S)-ketamine is threefold or twofold higher. Thus, a 50% reduction of dosage is possible to parable clinical results. Because of the faster elimination of (S)-ketamine, better control of anesthesia will be provided. In summary, the pharmacokinetic improvements of (S)-ketamine are characterized by a reduced drug load, along with more rapid recovery. The clinical use of (S)-ketamine: The clinical use of (S)-ketamine depends on its analgesic and sympathomimetic properties, whereas the anaesthetic potency remains in the background. In clinical anesthesiology, (S)-ketamine, especially bination with midazolam and/or propofol, can be used for short procedures with preserved spontaneous ventilation, for induction of anesthesia in patients with shock or asthmatic disorders, and for induction and maintenance of anesthesia in caesarean sections. Additional indications are repeated anesthesia, for example, in burn patients, analgesia during delivery and diagnostic procedures and intramuscular administration in uncooperative patients. The value of (S)-ketamine as an ponent for total intravenous anesthesia has not been defined yet. parison with opioides, the advantages are related to improved hemodynamic stability and reduced postoperative respiratory depression. When (S)-ketamine, especially bination with midazolam, is used for analgosedation in intensive care medicine, a reduction of exogenous catecholamine demand can be expected. Moreover, the effects on intestinal motility are superior to opioids. bination with midazolam and propofol, excellent control of analgosedation was found, making binations suitable for situations in which repeated neurological assessment of patients is necessary. In emergency and disaster medicine, (S)-ketamine is of outstanding importance because of its minimal logistic requirements, the chance for intramuscular administration and the broad range of use for analgesia, anaesthesia and analgosedation as well. Further perspectives of (S)-ketamine may be the treatment of chronic pain and the assumed neuroprotective action of the substance. |
9451487 | [Endocrine reactions, circulatory and resuscitation behavior in ketamine-midazolam anesthesia. A comparative study of ketamine racemate vs. (S)-ketamine in knee surgery]. | Clinically used ketamine is a racemic mixture of two isomers, (S)- and (R)-ketamine, in equal amounts. Previous investigations showed the anaesthetic potency of (S)-ketamine to be three times higher than that of (R)-ketamine. The aim of this study was pare the effects of (S)-ketamine/midazolam and racemic ketamine/midazolam on endocrine and cardiovascular parameters, recovery, and side effects in unpremedicated patients during knee surgery. |
9451488 | [Interactions of dry soda lime with enflurane and sevoflurane. Clinical report on two unusual anesthesias]. | We report two cases of unexpected courses of inhalation anaesthesia with sevoflurane and enflurane which were caused by the presence dry soda lime. Case 1: During mask induction of a healthy 46-year-old female patient for elective hysterectomy it was noted that the vaporizer setting of 5% sevoflurane (in 50% O2, 50% N2O) did not result in the expected increase of inspiratory sevoflurane concentration. At the same time, the anaesthesiologist observed that the patient did not lose consciousness while the temperature of the soda lime canister increased sharply and the colour of the soda lime turned to blue with condensing water visible in the tubing. It was later determined that this anaesthesia machine had not been used for more than 2 weeks. Analysis of the soda lime showed a water content of <1%. Case 2: Following intravenous induction of a non-smoking 64-year-old male patient for elective gastrectomy, it was noted that the itant inhalation of enflurane was associated with a sharp rise in the temperature of the soda lime canister, a colour change of the soda lime to blue and a decrease in the measured inspiratory enflurane concentration despite an unchanged or even increased vaporizer setting. Arterial blood gas analysis revealed a CO-Hb concentration of 8.8% with otherwise normal acidity and partial gas pressures. Immediate change of the absorbant resulted in a decline in the CO-Hb concentration to 6.9% within 3 h. It was later determined that the anaesthesia machine had not been used for 34 h. Analysis of the soda lime showed a water content of 5.4%. |
9451490 | [Heat production from reaction of inhalation anesthetics with dry soda lime]. | There are some case reports about excessive heat production in the absorbent canister when sevoflurane or enflurane are washed into a circle containing dried soda lime. This observation was often made in the DRAGER ISO 8 circle system with the gas inlet upstream of the soda lime canister with the gas-flow from bottom to top. |
9451489 | [Causes for the reaction between dry soda lime and halogenated inhalation anesthetics]. | All volatile anesthetics undergo chemical breakdown to multiple, partly identified degradation products in the presence of dry soda lime. These chemical reactions are highly exothermic, ranging from 100 degrees C for halothane to 120 degrees C for sevoflurane. The increase in temperature correlates with the moisture content of the soda lime, being maximal below 5%. Sevoflurane and isoflurane were exposed to dry soda lime in a circle system. The anaesthetic gas was condensed in a series of cold temperature traps and the degradation products of the volatile anesthetics were analysed using GC/MS. Surprisingly, neither sevoflurane nor its degradation products could be measured in the gas-flow emerging from the soda lime during the first 15-20 min of exposure. After 20 minutes, larger quantities of pounds C and D as well pounds A and B were detected. After 40-60 min of exposure, sevoflurane's degradation markedly decreased and unaltered sevoflurane emerged from the soda lime canister. Additionally, using isoflurane in the same experimental set-up resulted in various degradation products due to its reaction with dry soda lime. Obviously, all volatile anesthetics are prone to such a reaction. In conclusion, sevoflurane and isoflurane react with dry soda lime. These reactions are caused by the presence of ponents of soda lime, sodium hydroxide and potassium hydroxide. A modification of soda lime to prevent its reaction with volatile anaesthetics is discussed. |
9451492 | [Anesthesia unrelated triggering of a fatal malignant hyperthermia crisis]. | For incidents of malignant hyperthermia (MH) outside the hospital, a high number of unrecorded cases must be reckoned with because of an insufficient knowledge of emergency services and poor identification and documentation that make it impossible to classify acute situations under the diagnosis of malignant hyperthermia crisis. As a result, there are no statistical data in this field, and only case reports with a broad spectrum of suspected trigger mechanisms have been published. The case described in this report is a proved example of a non-anesthesia-related triggering of MH in a 21-year-old man who had had an anesthetic-induced MH manifestation in childhood, which was confirmed with an in vitro contracture test. After visiting a restaurant, he became unconscious and convulsive after consuming a high level of alcohol (2.9/1000). The first cardiocirculatory arrest occurred directly before hospitalization. After admission, the patient showed a full-blown MH episode whose subsequent fatality was unavoidable in spite of adapted and optimal therapy. Suspected trigger mechanisms seem to be multifactoral (excessive alcohol consumption, over-heating, mental stress) as a forensic investigation did not point to any particular signs of typical trigger substances. The case demonstrates again that an MH attack might be triggered under certain non-anaesthesia-related situations. For patients with an MH disposition, additional information on their behavior outside the hospital is required. |
9451493 | [S-(+)-ketamine. Circulatory interactions during total intravenous anesthesia and analgesia-sedation]. | General cardiovascular properties of ketamine: "In vitro", ketamine has moderate negative inotropic effects. "In vivo", a significant central sympathomimetic action with consecutive hemodynamic effects is dominant. The sympathomimetic potency of ketamine is one of the most significant pharmacological features of the substance with direct clinical implications. Monoanaesthesia with S-(+)-ketamine: After application of racemic ketamine or S(+)-ketamine as well, identic and significant increases in plasma catecholamines, arterial pressure and heart rate are observed. This outstanding sympathomimetic action is beneficial in induction of patients with shock or asthmatic state. TIVA and analgosedation with S-(+)-ketamine and midazolam: The sympathomimetic effect of S(+)-ketamine, and racemic ketamine as well, is mitigated by midazolam. Nevertheless, significant increases in heart rate and arteriel pressure might be observed. Clinical use of bination mon in short procedures like reposition maneuvers. Of greater importance is the use for analgosedation in patients with cardiovascular instability, particularly in patients with exogenous catecholamine demand. TIVA and analgosedation with S-(+)-ketamine and propofol: When S(+)-ketamine bined with propofol, the sympatholytic effects of propofol are counteracted by S(+)-ketamine, and stable hemodynamic conditions are presented. bination seems useful for TIVA in patients with hypotonic dysregulation or endocrine deficits like hypothyreosis and adrenal insufficiency. Furthermore, analgosedation with S(+)-ketamine and propofol is advantageous, when rapid recovery is necessary and negative circulatory effects should be avoided. |
9451499 | Long-lifetime Ru(II) complexes as labeling reagents for sulfhydryl groups. | We report the synthesis and spectral properties of two long-lifetime highly luminescent plexes containing either a sulfhydryl reactive iodoacetamido group or a less reactive choloroacetamido group, [Ru(bpy)2(5-iodoacetamido-1,10-phenanthroline)] (PF6)2 and [Ru(bpy)2(5-chloroacetamido-1,10-phenanthroline)](PF6) 2, respectively, where bpy is 2,2'-bipyridine. Ru(bpy)2(phen-IA)](PF6)2 was covalently linked to human serum albumin (HSA) and human immunoglobulin G (IgG). The photoluminescence lifetime of protein-bound probes approaches 1 microsecond under ambient conditions. In the absence of rotational motions, this probe displayed an anisotropy of 0.18 for excitation at 472 nm. Anisotropy decay data were used to determine the overall rotational correlation times of HSA and IgG. These long-lifetime sulfhydryl-reactive probes can be used to recover microsecond rotational motions and/or domain motions of proteins and/or plexes. |
9451500 | Quantitation of Cremophor EL in human plasma samples using a colorimetric dye-binding microassay. | This paper describes an analytical procedure for the quantitative determination of the pharmaceutical vehicle Cremophor EL in human plasma samples. The procedure is based on rapid binding of Coomassie brilliant blue G-250 to Cremophor EL following plasma protein precipitation with acetonitrile and analyte extraction with n-butylchloride. The binding of the dye to Cremophor EL causes a shift in the absorption maximum from 465 to 624 nm, which is monitored using an automated microplate-absorbance reader. The assay permits estimation of Cremophor EL concentrations in the range 0.05-1.00% (v/v) in 50 microL of human plasma, with percentage deviation and precision of < or = 12 and < or = 15%, respectively. The assay was subsequently used to measure Cremophor EL concentrations in plasma samples in support of a project to develop a pharmacokinetic model for pound in patients receiving paclitaxel. |
9451501 | Temperature titration: a new approach to the thermodynamics of oxygen binding to hemoglobin. | A cell was constructed in order to study hemoglobin's reaction with gaseous ligands. The temperature of the hemoglobin sample is systematically altered within a given temperature range (275-310 degrees K), while the percentage of oxygen in the equilibrating gas is kept constant. The equilibration time of the sample at each temperature step depends on sample concentration, ligand affinity, and absolute temperature; in most cases, the equilibration time is on the order of minutes. The construction of the partment allows the experimenter to vary the optical pathlength using specially designed spacers, thus making it possible to study hemoglobin-ligand interactions over a wide range of protein concentrations (0.1-200 mg/ml). Optical glass is used in the construction of the cuvette in order to optimize its optical stability over a long period of time. At equilibrium the absorption spectrum of the sample is collected and posed into the relative contributions of oxy-Hb, deoxy-Hb, and ferric-Hb, thus revealing the fraction of oxyhemoglobin as well as any baseline drifts and protein degradation. Temperature steps of 1 degree K are already sufficient to change the absorption spectra in a significant way. This type of setup is also advantageous in that the experimenter can change the sample at any point (temperature) without having to restart the entire experiment. This makes it possible to study the oxygen binding characteristics of unstable hemoglobins. Analyses of the binding curves obtained with this technique immediately yield the overall oxygen binding constants beta i together with the respective standard enthalpies delta H(i). |
9451502 | New N-glycans in horseradish peroxidase. | We describe here the structures of several new N-glycan oligosaccharides from horseradish peroxidase (HRP). Glycopeptides from HRP were digested with glycoamidase A (from sweet almond) to release the N-glycans. The oligosaccharides were reductively aminated with 2-aminopyridine, and separated by high-performance liquid chromatography on octadecylsilyl- and amide-silica columns for two-dimensional mapping (Tomiya et al., Anal. Biochem. 171, 73-90, 1988). The N-glycans were also analyzed by electrospray ionization mass spectrometry. Two different lots of HRP showed a considerable difference in their position. |
9451503 | Polypyrrole DNA chip on a silicon device: example of hepatitis C virus genotyping. | We describe in this article an oligonucleotide array constructed on a silicon device bearing a matrix of addressable 50-microns microelectrodes. Each electrode was covered by a conducting polymer (polypyrrole) grafted by an oligonucleotide (ODN). The DNA chip was prepared by successive electrochemically addressed copolymerizations of 5' pyrrole-labeled ODN and pyrrole. Following hybridization of the biotinylated amplified sample on the chip bearing a series of probes, detection was carried out by fluorescence microscopy through an R-phycoerythrin label. This technology was successfully applied to the genotyping of hepatitis C virus in blood samples. Results show good sensitivity and a high degree of dimensional resolution. |
9451504 | Capture of single-stranded DNA assisted by oligonucleotide modules. | Real-time biospecific interaction analysis was employed to monitor direct capture of a hepatitis C virus (HCV) derived polymerase chain reaction (PCR) product by nucleic acid hybridization. Different formats for hybridization were used to study the interaction between a single-stranded HCV PCR product and capture oligonucleotides immobilized on a sensor chip via streptavidin-biotin chemistry. By employing a prehybridization step in solution with nonbiotin plementary to the single-stranded target and adjacent to the immobilized probe, a significant capture was achieved parison to the low capture efficiency obtained using single immobilized probes (9-36 mer). High capture efficiencies were also observed when shorter immobilized probes were used bination with strings of adjacently positioned prehybridized probes (i.e., modules). Interestingly, the introduction of single nucleotide gaps between prehybridized and/or immobilized probes dramatically reduced the capture efficiency. These results suggest that flexible systems for capture could be designed from libraries of short oligonucleotides (9 mers) used in module fashion, taking advantage of stacking interactions between the oligonucleotides. The potential applications of such oligonucleotide-assisted capture systems are discussed. |
9451505 | A useful method to evaluate bone resorption inhibitors, using osteoclast-like multinucleated cells. | Since excessive bone resorption in postmenopausal osteoporosis is a pathological manifestation of the disease, it is important to control bone resorption activity of osteoclasts as a means of controlling the disease. To screen bone resorption inhibitors, a simple and quantitative method to assay bone resorption is needed. However, it has been difficult to prepare a lot of osteoclasts required for the screening of pounds in vitro. We used the method for the preparation of mouse osteoclast-like multinucleated cells in vitro and developed a useful method in which osteoclast-like multinucleated cells were placed on dentin slices and the calcium released from dentin into the culture medium was measured. Under the optimal conditions, the increase of the calcium concentration caused by bone resorption activity of the osteoclast-like cells was significant and inhibited by calcitonin in a dose-dependent manner. We also examined the inhibitory effect of calcitonin on the pit area caused by bone resorption and found that the decrease of the calcium released from dentin was correlated with that of the pit area. Furthermore, several known bone resorption inhibitors such as bisphosphonate, bafilomycin A1, and herbimycin A showed inhibitory effects on the calcium release from dentin slices. Thus, this simple method provides us a useful screening system to find bone resorption inhibitors with novel mechanisms. |
9451506 | Collagen zymography as a sensitive and specific technique for the determination of subpicogram levels of interstitial collagenase. | We describe the use of casting native collagen type I in SDS-polyacrylamide gel (collagen zymography) for the determination of interstitial collagenase. As with gelatin, the incorporation of collagen in the gels reduced protein migration and the need for making corrections for an accurate Mr evaluation. This method proved to be very sensitive: 0.1 pg of APMA-activated procollagenase could be detected, and specific levels of active gelatinase or stromelysin lower than 5 ng were inactive under our experimental conditions. It was used to demonstrate the increased expression of collagenase following treatment of human gingival fibroblasts with interleukin-1 beta; the amounts of enzyme quantified by either collagen zymography or immunodot blot assay parable. |
9451507 | Measurement of platelet aggregation peptide inhibitors by ultrasonic interferometry. | Several peptide inhibitors of thrombin- or collagen-induced platelet aggregation and of the interaction between glycoprotein Ib and von Willebrand factor were studied by a new method--ultrasonic interferometry (Echo Cell). Inhibition of aggregate formation in a concentration-dependent manner was observed. The sensitivity of the method was 3 to 40 times higher than that of classical turbidimetry. |
9451508 | Aryl thioglycoside-based affinity purification of exo-acting cellulases. | The influence of ligand-coupling chemistry and position on the interaction of exo-acting cellulases with an plementary ligand was investigated. p-Aminophenyl 1-thio-beta-D-cellobioside (APTC) was used as a representative affinity ligand to which exo-acting cellulases (cellobiohydrolases, CBHs) preferentially bind. A "crude" cellulase preparation from the fungus Trichoderma reesei served as an enzyme source. The adsorption properties of the two principal exo-acting CBHs in this preparation, CBH I and CBH II, are shown to be distinctly different under several scenarios. Their relative affinities, based on column elution behavior and partition equilibrium experiments, are shown to be highly dependent on the functional groups employed for ligand coupling, the extent of functional group hydrolysis, position of the mobile phase, and the inherent nature of the enzymes. The dependency on the chemistry of the supporting matrix was illustrated using agarose supports containing cyanate ester, N-hydroxy-succinimide, and epoxy functional groups. pared under apparent optimal conditions, the affinity of CBH II for immobilized APTC was approximately 10-fold that of CBH I. However, selective adsorption of CBH I or CBH II can be achieved by adjusting experimental parameters. |
9451509 | Isolation of the [3H]gabapentin-binding protein/alpha 2 delta Ca2+ channel subunit from porcine brain: development of a radioligand binding assay for alpha 2 delta subunits using [3H]leucine. | The novel antiepileptic agent gabapentin (Neurontin) binds with high affinity to the alpha 2 delta subunit of a voltage-dependent Ca2+ channel. We report here a simple purification scheme for detergent-solubilized alpha 2 delta subunits from porcine brain. This involves sequential chromatography on Q-Sepharose, Cu(2+)-charged iminodiacetic acid-Sepharose, wheat germ lectin-agarose, and Mono Q. The purified protein was essentially homogeneous by SDS-polyacrylamide gel electrophoresis with a subunit Mr of 145,000. Using [3H] gabapentin as the radiolabeled tracer and (S)-3-isobutyl gamma-aminobutyric acid to define nonspecific binding, the overall purification factor was 2760-fold and the apparent yield 26.6%. We also developed and validated a novel binding assay for alpha 2 delta Ca2+ channel subunits using the ligand pair L-[3H]leucine/L-isoleucine. Even in binding assays of crude brain membrane fractions, [3H]leucine proved to be remarkably stable and specific for the alpha 2 delta Ca2+ channel subunit. [3H]Leucine offers several advantages over custom-labeled [3H]gabapentin: it has a higher specific activity, is relatively inexpensive, and is available mercial sources. |
9451510 | An electrospray-ionization tandem mass spectrometry method for determination of the anomeric configuration of glycosyl 1-phosphate derivatives. | A rapid, simple, and sensitive method is described for the determination of the anomeric configuration of sugar 1-phosphates, sugar nucleotides, and polyisoprenyl-phospho-sugars. Negative-ion electrospray ionization of ole amounts of glycosyl 1-phosphate derivatives produces an intense signal of the [M-H]-deprotonated molecule which, by collision-induced dissociation, poses in a characteristic manner depending on cis/trans configuration of the 2-hydroxyl and phosphate groups of the glycosyl residue. A distinct feature of the product ion spectra of glycosyl 1-P and polyisoprenyl-P-sugars with cis configuration is the presence of abundant ions that correspond to the [M-H2O-H]- dehydration product and the [R-PO4-(C2H3O]- fragment arising from a cleavage across the sugar ring, where R is -H or -polyprenyl/dolichyl for glycosyl 1-P and polyisoprenyl-P-sugar, respectively. These two fragments, [M-H2O-H]- and [R-PO4-(C2H3O)]- are absent from the product ion spectra of sugar 1-P and polyisoprenyl-P-sugars with trans configuration. For sugar pounds with cis configuration produce, in tandem mass spectrometry, only one abundant fragment of nucleoside monophosphate, whereas those with trans configuration give nucleoside diphosphate as a major fragment ion. Accordingly, the anomeric configuration of a glycosyl 1-phosphate derivative can be easily determined by using electrospray-ionization tandem mass spectrometry provided that the glycosyl residue of known absolute configuration has a free 2-hydroxyl group and no other charge location. |
9451511 | Isolation of intact organelles by differential centrifugation of digitonin-treated hepatocytes using a table Eppendorf centrifuge. | A quick subcellular fractionation procedure using differential centrifugation, which is applicable to isolated and cultured cells, is presented. This technique was developed for studying the subcellular localization of phosphorylated proteins in isolated liver cells after various stimuli, but is also applicable to many other situations. The main difference with the usual techniques is that by including digitonin in the homogenization buffer, the procedure is greatly shortened. Furthermore, because the soluble fraction is separated from the particulate fraction very early in the fractionation procedure, subcellular organelles are not exposed to phosphatases and other soluble enzymes such as esterases and proteases during the fractionation. The entire procedure is carried out in an Eppendorf centrifuge, which allows isolation of the cytosolic fraction in less than 1 min, a washed nuclear fraction in about 4 min, a mitochondrial fraction in less than 10 min, and a washed light mitochondrial L fraction in about 40 min. Judging by the behavior of marker enzymes and the morphology of the fractions, the method is parable to classical procedures. |
9451512 | A fluorescence polarization competition immunoassay for tyrosine kinases. | We have recently reported a homogeneous, nonradioactive fluorescence polarization method to assay protein tyrosine kinase activity. Our original approach can only be used with a peptide substrate and requires large amounts of anti-phosphotyrosine antibody. To e these problems an alternate fluorescence petition immunoassay was designed and evaluated. In this assay, phosphorylated peptide or protein produced by kinase reaction pete with a fluorescent phosphopeptide used as a tracer for plex formation with phosphotyrosine antibody. In this format kinase activity will result in the loss of the polarization signal. To validate the fluorescence petition immunoassay, Lck activity pared with a monly used 32PO4-transfer assay using Lck peptide or enolase as the substrate. In both the assays, Lck activity showed a similar dependence on ATP, Lck enzyme, and the peptide/enolase substrate concentrations with the FP signal inversely proportional to the amount of 32PO4 transferred to the substrate. Inhibition by staurosporine and the Lck inhibitor 4-amino-5-(methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine was similar in these two assays. The advantages of this assay over other kinase assays include use of nonisotopic substrates and a more simple procedure in which the kinase assay is done in a single tube (well of a microtiter plate), without separation, precipitation, or washing. This method is easily automated for high-throughput drug discovery screening. |
9451513 | High-performance liquid chromatographic-fluorometric determination of glyoxal, methylglyoxal, and diacetyl in urine by prederivatization to pteridinic rings. | A sensitive and simple liquid chromatographic method to determine glyoxal, methylglyoxal, and diacetyl is reported. The method is based on the conversion to the corresponding pteridin derivatives (pterin, 6-methylpterin, and 6,7-dimethylpterin). The proposed method using fluorometric detection has been applied to the determination of the three pounds in human urine. Linearity (peak area vs concentration of alpha-dicarbonyl) was observed at least up to 43 microM. Detection limits of 32 pmol for glyoxal, 11 pmol for methylglyoxal, and 99 pmol for diacetyl were calculated (20 microliters was injected). Levels of 132 microM for glyoxal and 15 microM for methylglyoxal were determined in normal urine samples, while diacetyl was not detected. |
9451516 | The use of intravenous nitroglycerin for cervico-uterine relaxation: a review of the literature. | The safety, predictability, and ease of intravenous administration of nitroglycerin (NTG) have been firmly documented. In recent years, intravenous NTG e to the attention of the obstetrician as a potent uterine relaxant. Intravenous nitroglycerin has been used to relax the uterus during manual extraction of retained placenta and to permit replacement of a pletely prolapsed, inverted uterus. The use of this agent as a tocolytic has previously been reported in cesarean delivery of twins, in cases of intra partum external cephalic version, and for internal intrapartum podalic version of the second twin. This new procedure was also used for fetal head entrapment after vaginal breech delivery. The authors report a review of the literature about this subject. |
9451518 | The effect of pregnancy on endometriosis in baboons (Papio anubis, Papio cynocephalus). | This study was performed to test the hypothesis that endometriosis undergoes regression during pregnancy. |
9451517 | Induction of labor with intravaginal misoprostol versus intracervical dinoprostone. | Sixty five pregnant women who had the indication for labor induction were randomized in a clinical trial to receive 100 micrograms intravaginal misoprostol or intracervical gel of 0.5 mg dinoprostone. The mean time from induction to delivery for the misoprostol group was 7.6 +/- 1.9 versus 8.2 +/- 5.9 (hours +/- SD) for the dinoprostone group. There were no significant differences between groups in gestational age, induced labor rates, type of delivery, fetal e and plications. We found that intravaginal misoprostol tablet is as effective as intracervical dinoprostone for inducing second and third trimester labor. |
9451523 | Type III Ehlers-Danlos syndrome and pregnancy. | We report a case of type III Ehlers-Danlos syndrome with a favourable e. We review the literature and do not consider that pregnancy in patients with type III Ehlers-Danlos Syndrome represents a high risk situation. |
9451524 | Solitary intracranial metastases from primary endometrioid ovarian cancer. | A rare case of involvement of the Central Nervous System characterized by brain and subsequent cerebellar metastases without abdomino-pelvic spread is reported. The patient was treated by craniotomy plus external radiation to the brain. Subsequently, Carboplatin-based chemotherapy was started when paraaortic lymph-nodes involvement has been detected. Follow-up is uneventful after plete remission. |
9451527 | Effect of hyperbaric oxygen on intercellular adhesion molecule-1 (ICAM-1) expression in murine lung. | The lung is one of the most susceptible organs to the toxic effect of high pressure oxygen. However, the contribution of the cellular adhesion molecules and inflammatory leukocytes in the pulmonary oxygen toxicity, especially in an acute exudative phase, is not well understood. In the present study we have investigated the toxic effect of hyperbaric oxygen (HBO) expressed by the analysis of the intercellular adhesion molecule-1 (ICAM-1) on the pulmonary vascular endothelial cells and leukocyte function. |
9451528 | Information about venous gas emboli improves prediction of hypobaric decompression sickness. | Information about venous gas emboli (VGE) detected in the pulmonary artery such as the occurrence of VGE, Grade of VGE, the time when VGE first appear, and the time course of the Grade or occurrence of VGE, could be used to better assess the probability of pression sickness [P(DCS)] in any hypobaric pression. We hypothesized that these data would improve the estimate of P(DCS) since objective measurements of the pression stress are available for the individual. |
9451529 | The convective afterdrop component during hypothermic exercise decreases with delayed exercise onset. | Following cold water immersion, the post-cooling decrease in esophageal temperature (Tes) (i.e., afterdrop) is 3 times greater during exercise than during shivering, presumably due to increased muscular blood flow and convective core-to-periphery heat loss with exercise (J. Appl. Physiol. 63:2375, 1987). We felt that if exercise were mence once the afterdrop period during shivering plete, the threat of a further decrease in Tes (i.e., a second afterdrop) during the subsequent exercise would be minimized because much of the convective capacity for core cooling would already be dissipated. |
9451530 | Control of isometric force in hypergravity. | Previous work suggests that proprioceptive signals are degraded in hypergravity (hyper-G). We therefore, expected that production of finely graded force is disturbed as well. |
9451531 | Cardiovascular changes during and after different LBNP levels in men. | This study quantifies hemodynamic and thoracic impedance (TI) changes with four levels of lower body negative pressure (LBNP) from -15 to -65 mm Hg in seven healthy men in supine position 20 min before (pre-LBNP), 30 min during, and 20 min after suction (post-LBNP) as well as without suction (LBNP-0, rest control). |
9451533 | Point prevalence of barotitis in children and adults after flight, and effect of autoinflation. | The mon cause of barotitis is pressure changes during descent in aviation. Equilibration is normally achieved by swallowing, jaw movements, yawning, or chewing, but some have to perform a Valsalva maneuver several times during descent and even by these means some fail. The aim of the study was to estimate the point prevalence of barotrauma in children and adults after flight, and to test the effect of an autoinflation device (Otovent), in improving negative middle ear pressure after flight. Questionnaires and Otovent, were distributed to all air passengers in eight ing flights. The questionnaires inquired about nasal allergy, nasal congestion, previous and actual ear pain, use of decongestants and experience of inflating the Otovent set during descent. After flight, the passengers were offered an ear examination including otoscopy and tympanometry both before and after a Valsalva maneuver, as well as after Otovent inflation. Otoscopic signs of barotitis were found in 10% of the adults and in 22% of the children. Negative middle ear pressure of more than 10 hPa after landing was found in 20% of the adults and in 40% of the children. The Valsalva maneuver normalized the pressure in 46% of the adults and in 33% of the children. Of the adults, 73%, and of the children, 69% with an unsuccessful Valsalva maneuver could improve or normalize the middle ear pressure by inflating the Otovent set. In conclusion, we mend autoinflation using the Otovent set to air passengers with problems clearing the ears during flight. |
9451532 | The effects of linear acceleration on distortion product otoacoustic emissions in human ears. | The effect of high levels of linear acceleration (G) on the cochlea has never been studied prospectively. |
9451534 | Magnetic resonance imaging of the paranasal sinuses in divers. | CT and magnetic resonance imaging (MRI) frequently reveal asymptomatic paranasal sinus mucosal hypertrophy in the general population. |
9451535 | Effects of exercise training mode on the cardiovascular responses to lower body negative pressure in males. | Endurance-trained males may be more prone to orthostatic hypotension than untrained subjects and this is reflected in differences in their cardiovascular responses to lower body negative pressure (LBNP). It is uncertain if the type of endurance training used affects these responses. |
9451537 | The "Space Cycle" Self Powered Human Centrifuge: a proposed countermeasure for prolonged human spaceflight. | The Self Powered Human Centrifuge, or Space Cycle, is a countermeasure to the adverse physiologic effects of prolonged human exposure to spaceflight microgravity. This unique device simultaneously provides exercise, impact loading and gravity analogous acceleration to emulate conditions on Earth. One or two crewmembers pedal themselves about a shaft mounted to the space craft located "above" their heads. This creates a short arm centrifuge with a head-to-toe acceleration orientation. The potential advantages of the Space Cycle include: a) reversal of cephalad fluid shift, minimizing post flight orthostatic intolerance; b) pedaling to maintain muscular and cardiovascular fitness; and c) enhancement of skeletal homeostasis by impact loading with a pedal-crank mounted cam and frame mounted resistive device. Other anticipated advantages include generation of usable electricity, physiologic monitoring and a means of mass measurement. Motion sickness is controlled with restraints and virtual reality headsets. The device patible with International Space Station dimensional constraints. |
9451536 | Partial renal resistance to arginine vasopressin as an adaptation to high altitude living. | The normal physiological response to high altitude (HA) is a decrease in total body water (TBW) and plasma and extracellular volume. The present investigation was designed to determine the mechanisms of the decrease in TBW with HA adaptation. |
9451538 | Longitudinal studies of behavior and performance during a winter at the South Pole. | Evidence of a specific pattern of performance decrement in isolated and confined (ICE) environments has not been consistently demonstrated in previous research. |
9451546 | Systematic assessment of social phobia in clinical practice. | The purpose of this review is to propose a systematic approach to the assessment of social phobia for monitoring treatment e in clinical settings. A selection of measures is available, including questionnaires and structured interviews varying in plexity, and content. To design an assessment protocol for a particular patient or patient population, the clinician needs to be familiar with the characteristics of these available measures. The measures selected for detailed description and discussion here: (a) are specifically designed to assess social anxiety and social phobia, (b) have been demonstrated to have acceptable psychometric characteristics, and (c) have been utilized in treatment e research. Five questionnaire measures will be reviewed: (1) the Social Phobia and Anxiety Inventory (SPAI) (Turner et al., 1989a: Psychol Assessment 1:35-40), (2) the Social Interaction and Anxiety Scale (SIAS) (Mattick and Clarke, 1989 in Heimberg et al., 1992), (3) the Social Phobia Scale (SPS) (Mattick and Clarke, 1989 in Heimberg et al., 1992: Behav Therapy 23:53-73), (4) the Fear of Negative Evaluation Scale (FNES) (Watson and Friend, 1969: J Consult Clin Psychol 33:448-457), and (5) The Social Anxiety and Distress Scale (SADS) (Watson and Friend, 1969: J Consult Clin Psychol 33:448-457). Two interview measures will be reviewed, the Liebowitz Social Anxiety Scale (LSAS) (Liebowitz, 1987: Modern Problems Pharmacopsych 22:141-173) and Brief Social Phobia Scale (BSPS) (Davidson et al., 1991: J Clin Psychiatry 52:48-51). Measures developed for specific subgroups, including patients with speech anxiety and musical performance anxiety, as well as the application of other evaluation methods, such as the Behavioral Assessment Test, will also be discussed. Guidelines for selecting appropriate social phobia measures for varying clinical and research situations will be proposed that take into consideration the strengths and weaknesses of these methods. |
9451547 | Child and parent reports of childhood anxiety: differences in coping styles. | This pares children anxious only on parent report (PR) with those anxious on self-report (SR) and self- and parent report (SPR) to examine the reasons for the reporting differences. Sixty-five children aged 7-12 years who met criteria for one or more Axis I anxiety disorders (25% orbid nonanxiety pleted standardized measures of anxiety, depression, and coping style. pleted measures of child psychopathology and adult coping style. Assessing pleted the Global Assessment of Functioning. All parents endorsed anxiety in their children. Based on their responses on standardized self-report measures of anxiety, children were classified as endorsing anxiety (SPR group) or not endorsing anxiety (PR group). Multivariate analysis of variance revealed that children in the SPR group endorsed more depression and employed a greater variety of coping strategies than children in the PR group. The two groups did not differ on parent or clinician measures. These findings suggest that reporting differences may be related to differences in coping styles in anxious children. SPR children may over report anxiety symptoms due to feelings of decreased self-worth associated with depressive thinking, whereas PR children may be able to distract themselves from their anxieties. The lack of difference in functioning between the two groups suggests that self-report anxiety questionnaire scores are not necessarily indicative of severity. |
9451548 | Personality and PTSD II: personality assessment of PTSD-diagnosed Vietnam veterans using the cloninger tridimensional personality questionnaire (TPQ). | Examined Tridimensional Personality Questionnaire (TPQ) responses of 53 Vietnam veterans with Combat-Related Posttraumatic stress disorder. pared with normative data, veterans were found to be high on harm avoidance (HA), low on reward dependence (RD), and high on novelty seeking (NS). High HA and high NS scores were predictive of increased PTSD symptom severity as assessed by the MMPI-2 PK (PTSD)scale, Mississippi Combat Scale for PTSD (M-PTSD), and Beck Depression Inventory (BDI). Low RD was associated with higher scores on both the MMPI-2 PK and M-PTSD scales. The observed "high HA-low RD-high NS" TPQ configuration is consistent with previous research findings/clinical observations, and provides insights into a pattern of dysfunctional personality traits often observed in this population. |
9451549 | Hypochondriacal concerns and somatization in panic disorder. | To clarify the relationship between panic disorder and the symptoms of hypochondriasis and somatization, we evaluated these symptoms and diagnoses in patients attending an Anxiety Disorders Clinic. Structured clinical interviews, self-report measures, and symptom diaries were used to assess 21 patients with panic disorder, 23 patients with social phobia, and 22 control subjects with no psychiatric disorders. Ten of the patients with panic disorder (48%) also met DSM-IV criteria for hypochondriasis, whereas only one of the patients with social phobia and none of the healthy control subjects met the criteria for this diagnosis. None of the participants met DSM-IV criteria for somatization disorder, even though both anxiety groups reported high levels of somatic symptoms. The panic disorder group reported higher levels of fear about illness and disease conviction and endorsed more somatic symptoms than did the other groups. A higher proportion of panic disorder patients reported previously diagnosed medical conditions (48%) pared with patients with social phobia (17%) or healthy control subjects (14%). The panic disorder patients with DSM-IV hypochondriasis obtained higher scores on measures of hypochondriacal concerns, somatization, blood-injury phobia, and general anxiety and distress than did the panic disorder patients without hypochondriasis. The results suggest a strong association between panic disorder and hypochondriasis. |
9451551 | T-cell-rich B-cell lymphoma: fine-needle aspiration cytology and immunocytochemistry. | Cytomorphologic and immunocytochemical characteristics of FNA aspirates from 5 patients with T-cell-rich B-cell lymphoma are described. The aspirates were dominated (over 90%) by small mature lymphocytes, but there was a sparse admixture of large, immature lymphoid cells, some of which mimicked Hodgkin's or Reed Sternberg's cells. The cytologic picture of 3 cases was similar to that of Hodgkin's disease of lymphocytic predominance. Two cases presented, in addition to ponents described above, fragments of small vessels and epithelioid cells, which raised the possibility of true T-cell lymphoma. Immunocytochemical analysis of cytospin preparations showed that the mature small lymphocytes were of T-phenotype, while the large cells were of B-phenotype. Light-chain restriction was demonstrated in all cases, and monoclonality for kappa and lambda was shown in 4 cases and 1 case, respectively. Three cases had a previous histological diagnosis of Hodgkin's disease, which was revised to T-cell-rich B-cell lymphoma as a consequence of the cytologic and immunologic findings in aspirates from recurrent/remaining lymphoma manifestations. It can thus be concluded that immunocytochemistry in conjunction with cytomorphology on fine-needle aspirates will allow a conclusive diagnosis of T-cell-rich B-cell lymphoma and its differentiation from Hodgkin's disease and T-cell lymphomas. This distinction, from a prognostic and therapeutic standpoint, is of utmost importance. |
9451552 | Prospects for a prophylactic HPV vaccine: rationale and future implications for cervical cancer screening. | Cytologic screening bination with ablative therapy has helped reduce cervical cancer mortality in the developed world. Despite the success of this approach, cervical cancer remains a major cause of death, especially among women with limited access to health care. Recognition that human papillomaviruses (HPVs) are the main etiologic agent in cervical cancer suggests that a prophylactic vaccine could reduce the incidence of HPV infection and, therefore, achieve cancer control with reduced reliance on costly screening programs. In this review, the rationale for developing a prophylactic HPV vaccine and the potential impact that vaccination would have on cervical cancer screening are discussed. |
9451553 | Combining QUANTICYT karyometric analysis with architectural confocal-aided cytology to prognosticate superficial bladder cancer. | For this study, bladder washings of 923 patients with a follow-up for superficial bladder cancer were used. For the prognostication of each case (follow-up period up to 20 mo), two parameters were used: tumor recurrence and the event of (progressing) invasive growth. Each sample was classified as negative, low grade or high grade, based on confocal-aided architectural cytology. The feature architecture was based on the images of the epithelial fragments as seen in the Feulgen stain, which also could be visualized in confocal microscopy. The same three classes were also used for grading the samples according to the QUANTICYT system, in which DNA and morphometry of nuclei were automatically assessed. The 532 cases graded as QUANTICYT high had a worse prognosis than the 391 cases with QUANTICYT low. In addition, architectural cytology contributed significantly for the prognostication of cases classified as QUANTICYT high, the 228 nonconcording cases faring better than the 304 concording ones. For QUANTICYT low, the 156 nonconcording cases had also a lower recurrence rate than the 235 concording ones, but this difference was only significant in patients followed for up to 8 mo. These findings indicate that QUANTICYT grading supplemented by architectural cytology supplies the clinician with valuable prognostic information which can be used to limit cystoscopies. |
9451554 | Chromosomal markers: signposts on the road to understanding neoplastic disease. | Classical cytogenetic studies have defined chromosomal attributes of tumors that are useful at present in the diagnosis, classification, and management of leukemic disorders, and in some solid tumors as well. Recent advances in molecular techniques now permit application of some forms of chromosomal analysis to studies in cytopathology. However, to fully understand the present and potential uses of these tumor markers, it is necessary to have some background and perspective on classical cytogenetics. |
9451555 | Recent advances in thin-layer cytology. | In recent years liquid-based cytology has emerged as an alternative to conventional cytopreparatory methods. In particular, the ThinPrep system has found broad acceptance in non-gynecologic cytopreparation. Many laboratories have successfully applied this technique to body fluids (e.g. urine, pleural effusions), brushing samples (e.g. gastrointestinal tract, lung) and fine-needle aspiration. parative studies have shown the ThinPrep system to perform as well as or better than conventional preparations in nongynecologic cytology; plus, the residual cells within the vial can be used for DNA analysis or immunohistochemical and other special studies. Recently, the ThinPrep 2000 system has been approved for use in gynecologic cytology. This approval was based on a large, multicenter clinical study that showed the ThinPrep system to be favored over the conventional Pap smear for the detection of low-grade squamous intraepithelial lesions, or more severe lesions. At screening centers the improved rate of detecting low grade squamous intraepithelial lesions (LSIL) or more severe diagnosis was up to 73%, with an average improvement of 65% pared to the conventional Pap smears. Also, for specimen adequacy, the ThinPrep method was statistically favored over conventional cytology methods. This multicenter clinical trial demonstrates the ThinPrep 2000 system was more effective than the conventional Pap smear for the detection of atypical cells and cervical cancer and its precursor lesions. In addition, by collecting cells in a liquid-based medium the opportunity is present to improve the Pap test by adjunctive testing for Human Papilloma Virus or other procedures. This creates the opportunity for improved triage and management of patients with cervical abnormalities. |
9451557 | Flow cytometry in diagnostic cytology. | Flow cytometry (FCM) is a useful adjunct to cytologic examination, because the quantitative biochemical information it plements the morphologic information gained during visual examination. It aids in the interpretation of bladder washings, and is particularly useful for the assessment of lymphoid lesions, whether they originate from fine-needle aspiration, cerebrospinal fluid, or effusions. Optimal use of FCM frequently requires assessment of more than one parameter; simultaneous use of cell differentiation markers and nuclear DNA quantitation is often significantly more useful than either alone. Despite the utility of FCM, however, the potential for future development appears to be limited. Improvements in image cytometry allow reasonable assessment of ploidy and S-fraction to be made from specimens prepared on glass slides. Multiparameter measurements may also be plished with imaging techniques, which allow the further advantage of visual identification of cells with equivocal morphologic changes. The development of artificial intelligence methods for use with imaging technology has also significantly exceeded that of FCM. Finally, image cytometry is often more useful for samples with few cells. Other challenges are posed by immunocytochemical methods pete with flow cytometry as tools for assessment of proliferation. Given the relatively high cost of FCM instrumentation, survival of FCM as an ancillary technique in cytopathology will require further technical refinements to offset the advantages currently associated with image cytometry and immunocytochemistry. |
9451558 | Automation in cytology: a survey conducted by the New Technology Task Force, Papanicolaou Society of Cytopathology. | Despite the overwhelming interest in the development of puter based technologies in the last several years, the role of automation in cytology has remained controversial. The potential of these technologies in the reduction of false negative results in pap smears is well recognized. However, there is still remarkable confusion as how to incorporate automation in the routine practice of cytology. This prompted the New Technology Task Force of the George Papanicolaou Society of Cytopathology to design a survey to seek the opinion of those engaged in cervicovaginal cytology screening regarding the value of automation in cytology. In 1996, a ten question survey was sent to 1800 cytopathology laboratories throughout the nation. The response rate was 23% (416/1800). The responders represented laboratories varying from those with less than 5,000 pap smears to those with over 100,000 cases per year. The majority of the responders did not believe that automation is essential for cervicovaginal cytology. This was evidenced by the fact that only 12% of the laboratories were engaged in automated cytology and predominantly used it for quality control measures. The inability of small laboratories to absorb the extra expense involved in the integration of automated cytology in their practice, particularly in the current era of managed care was a major concern. There was also concern about the potential promise of patient care by the drive for corporate profits and the dissemination of wrong information to the public and physicians. Suggestions most frequently proposed included appropriate patient and physician education about the merits and pitfalls of the pap smear, and also endorsing an affordable universal fee for pap smears. Rescreening for all pap smears, reassessing the benefits of automation in cytology and development of the standards were other proposals. Partnership with larger cytology laboratories, creation of "cytology consortiums" with shared resources to provide regionalized automated rescreening services were also strongly suggested. This survey clearly indicates the need for further evaluation of automation in cytopathology and a focused attention to various issues surrounding cervicovaginal cytology screening. |
9451559 | Fine-needle aspiration is limited in the classification of benign breast diseases. | Fine needle aspiration (FNA) has been proven to be accurate for the detection of breast carcinomas. However, its utility in the classification of benign breast lesions is less clear. We therefore undertook a study of 76 adequate preoperative FNAs of the breast from patients whose surgical biopsies of the breast were shown to be benign (18 nonproliferative diseases, 30 fibroadenomas, 19 proliferative breast diseases without atypia, and 9 proliferative breast diseases with atypia). A number of architectural and cellular features on cytology were evaluated. Histology slides were also reviewed. Both cytology and histology specimens were categorized as nonproliferative disease, fibroadenoma, proliferative breast disease without atypia, and proliferative breast disease with atypia. There was exact diagnostic correlation between cytology and histology in only 42 (55%) of the 76 cases. No cellular or architectural features on FNA examined correlated with the presence of epithelial proliferation on histology. The presence of two epithelial cell populations (one unremarkable and one atypical), small but prominent nucleoli, and nuclear pleomorphism on FNA significantly correlated with the presence of atypia on histology. However, these features are also present in breast lesions without proliferation or atypia, and are not diagnostic of atypical proliferative lesions of the breast. Therefore, FNA of the breast is limited in classifying benign breast diseases. |
9451560 | Intraoperative cytologic diagnosis of granulomas: a retrospective study of 156 cases. | To avoid contamination of equipment and reduce risks of infection, intraoperative cytology (IOC) is a useful substitute to conventional frozen section in the diagnosis of infectious diseases. One of the various histomorphologic patterns of infections is the granuloma, which sometimes may be difficult to diagnose cytologically. In an attempt to assess accuracy and pitfalls of IOC in the diagnosis of granuloma, cases diagnosed as granuloma on IOC or on permanent sections (PS) at George Washington University Medical Center were collected for the period of September 1990 to March 1996. Cyto-histologic correlation was performed. During that time, a diagnosis of granuloma in either the IOC or PS was rendered in 156 of 5,901 IOC cases. IOC showed definite granuloma (87), suspicious for granuloma (23), and neither definite nor suspicious for granuloma in 46 cases. The latter group corresponded to neoplasms (5) and benign conditions (41). Eighty-five cases were accurately diagnosed as definite granuloma by both IOC and PS. Fifty-seven cases diagnosed as granuloma by PS corresponded on IOC to suspicious for granuloma (11), benign smear (41), and neoplasms (5). Only two cases were incorrectly diagnosed as granuloma on IOC: a neoplasm and a case of fibrosis. Overall, four cases of neoplasms were interpreted as suspicious for granuloma (3) or definite granuloma (1) on IOC, and five cases of granulomas were misdiagnosed as neoplasms on IOC. Four of these nine case were deferred for a PS diagnosis. IOC is a useful tool in the diagnosis of granulomas with a sensitivity of 60% and specificity of 99% and positive and negative predictive values of 98% and 99%, respectively. Rarely, neoplasms may be misdiagnosed as granulomas and vice versa. |
9451561 | Another quality assurance issue--amended reports: what do we really know about them? | The Clinical Laboratory Improvement Amendment (CLIA) of 1988 requires that if a cytology/histology discrepancy is discovered which is significant and affects patient care, an amended report should be issued (Clinical Laboratory Improvement Amendments, Fed Reg 1992;57:7169). Since little is known about such amended reports, a survey was developed to assess how individuals handle discrepancies. The Quality Assurance Task Force from the Papanicolaou Society of Cytopathology created a survey to assess these methods and sent it to all of their members. Fifty-one individuals responded to the survey. Methods vary widely among institutions. On average, 107 cytologic/histologic correlations are performed each month with the discovery of approximately 2 major and 11 minor discrepancies. Thirty-nine responders utilize written amended reports and telephone clinicians when a major discrepancy is found. Thirty-eight individuals indicated that their place of employment has a written policy concerning discrepancies. Time spent in quality assurance issues averaged 8 hr per wk for cytotechnologists and 3 hr per wk for pathologists. Although amended reports are required when significant discrepancies are revealed, a standard practice does not exist. |
9451562 | Brush cytology of herpes simplex virus infection in oral mucosa: use of the ThinPrep processor. | Evaluation was made of oral scraping specimen using Cytobrush from 11 patients with clinical suspicious lesions for herpes simplex virus (HSV) infection. In this study, oral brush cytology prepared using an automated smear apparatus (ThinPrep method) has been applied. The smears prepared by ThinPrep are equally well suited for screening purposes, producing highly cellular specimens with well-preserved cytoplasm and nuclei. The results obtained on the 11 patients, four cytologic specimens, showed pathognomonic viral cellular changes of HSV infection. Viral isolation studies were performed on 10 of the 11 patients and ten specimens tested positive for HSV by culture. Of the ten HSV positive isolates, six were positive by either cytology or immunocytochemical staining. Of the two smears showing HSV positive cells, both smears were also confirmed by in situ hybridization (ISH) with a biotinylated clone DNA probe. Using the ICC technique, detection of HSV antigen in oral scraping smears was of great value in the diagnosis of oral HSV infection, especially in cases of equivocal lesions. Oral cytology by means of ThinPrep method obviously deserves additional trials as an adjunct in the cytology of HSV-suspected lesions. |
9451563 | Assessment of fine-needle aspiration sampling technique in thyroid nodules. | A prospective two-yr study was undertaken to assess the heterogeneity of thyroid nodules using the fine-needle aspiration (FNA) technique of systematic regional sampling. In addition, we determined the number of regions to be sampled to minimize non-diagnostic results, and to optimally characterize thyroid nodules. |
9451565 | [The importance of differential analysis of formal thought disorders in confusion psychosis and cataphasia. Incoherence of thematic choice and incoherence with logical and linguistic errors]. | Formal thought disorders are usually regarded as a central symptom of schizophrenic psychoses, but nevertheless as diagnostically non-specific. Karl Leonhard, therefore, differentiated in his classification of endogenous psychoses between a whole lot of diagnostically specific types of formal thought disorders. He described two psychoses, of which formal thought disorder is the main psychopathological feature, i.e. confusion psychosis and cataphasia. By means of an analysis of tape-recorded utterances of patients with such psychoses we demonstrate the phenomenological differentiation of the distinct types of thought disorder in these psychoses. In confusion psychosis the disturbance concerns the thematic organisation and target-oriented direction of the train of thought. Characteristically, an "incoherence of thematic choice" results, reflecting a disturbance on the level of organisation of discourse. The concepts, ideas and themes itself are organised in a logically correct manner and prehensible. The thought disorder in cataphasia, however, shows severe logical faults in the connection of concepts and ideas, as a result of which single themes and ideas e a logical and prehensible. Moreover, cataphasic thought disorder goes beyond the level of discourse organisation and extends to disturbances of linguistic functions including mistakes on a semantical and syntactic level. These observations correspond well with the widely accepted assumption of a modular organisation of cognitive and linguistic processes. The thought disorder in prognostically unfavourable cataphasia concerns "basal" logical, semantic and syntactic systems, which remain uninfluenced in the prognostically favourable confusion psychosis. In the latter, therefore, the disorder is restricted to the higher functions of organisation of discourse. |
9451566 | [Transcranial magnetic stimulation as an alternative to electroshock therapy in treatment resistant depressions. A literature review]. | Transcranial magnet stimulation (TMS) is a low-risk method for direct and localised stimulation of the cerebral cortex. For several years it has played an important part in measurements of the central motor conduction time (magnetically evoked potentials/MEP). Further technical and methodological developments, such as high-frequency (rapid rate TMS/rTMS) or triggered stimulation have led to broad scientific application of this method. Electric convulsive therapy (ECT) has proved its value in the treatment of various psychiatric disorders, especially in pharmaco-resistant depression. The therapeutic mechanism is actually unclear. However, the generalised convulsive fit appears to be the precondition for the therapeutic effect. A disadvantage lies in the risk inherent in the necessary general anaesthesia and the possible side effects, such as transitory states of confusion and transient mnestic deficits. Bearing in mind the possibility that TMS could have the same effects as ECT due to stimulations below the convulsion threshold or to the direct or indirect stimulations of so-called disorder-specific key regions, several pilot studies and some controlled studies have been published during the past three years on its efficacy in depressive disorders. The results were reported on and critically evaluated. The results of this survey of the literature on the subject is that (r)TMS does not represent an alternative to ECT in the therapy of pharmaco-resistant depressions. Due to its slight and only transient antidepressive effect, (r)TMS is also, in our opinion, not suitable as so-called add-on therapy as plement to antidepressant medication. |
9451567 | [Medical and ethical problems in the classification of psychiatric disorders. The "Wurzburger Schlussels" of 1933]. | In 1930 a new classification of mental disorders, later on known as "Würzburger Schlüssel", was developed and tested for two years. It replaced the "Reichsirrenstatistik" from 1901, and included new disease entities. This pragmatical classification was mainly descriptive including a few elements regarding aetiology and course of disease. The "Würzburger Schlüssel" put emphasis on addictions (especially alcoholism), psychopathy (in teenagers as well as in adults) and on the sequelae of syphilis. However, most of the diseases in elderly patients were not classified as being due to the various descriptive disease entities, but to the age related category. The fundamental problems of the development and practice of a classification of psychic disorders and the panying medical and ethical problems, which are still important today, are discussed. |
9451568 | [The use of alternative medicine by multiple sclerosis patients--patient characteristics and patterns of use]. | The use of alternative medicine is growing in all Western countries. Little is known about the modalities and patterns of use of alternative medicine by patients suffering from multiple sclerosis. |
9451569 | [Olivopontocerebellar atrophy--a heterogenous morphologic syndrome]. | Among the neuropathologically defined spinocerebellar degenerations, olivopontocerebellar atrophy (OPCA) represents a morphologic syndrome underlying different clinical, genetic, and biochemical conditions. Clinical and genetic classification systems include OPCA in sporadic cerebellar ataxias such as multiple system atrophy as well as in different autosomal recessive, autosomal dominant and X-chromosomal recessive cerebellar ataxias. According to findings of the last two decades, the historically derived term OPCA should be avoided in clinical use and should be regarded as a diagnostic contribution. A proper diagnostic classification of individual cases, however, has to consider all neuropathological, clinical and genetic data. |
9451570 | WCALive: broadcasting a major medical conference on the Internet. | Live video and sound from the 11th World Congress of Anaesthesiology in Sydney, Australia were broadcast over the Internet using the CuSeeme software package as part of an ongoing evaluation of Internet-based munication in the delivery of Continuing Medical Education (CME). This was the first time such a broadcast had been attempted from a medical convention. The broadcast lasted for four days, during which a bination puter hardware and software was established. Technical issues relating to broadcast of these real time signals over ISDN links and the Internet itself were addressed. Over 200 anaesthetists from around the world were able to 'attend' the plenary sessions via the Internet. Evidenced by feedback received audio reception was quite good. Video reception was less successful for those receiving the broadcast via a modem based Internet connection. The received signal in such circumstances was adequate to provide a video presence of the speaker but inadequate to allow details of 35 mm slides to be visualised. We conclude that this technology will be of use in the delivery of CME materials to remote areas provided simultaneous viewing of high resolution still images is possible using another medium, such as the World Wide Web. |
9451571 | The inspiratory to end-tidal oxygen difference during exercise. | Fast paramagnetic oxygen analyzers have made it possible to measure inspiratory to end-tidal oxygen concentration difference (P(I-ET)O2) breath-by-breath. It is now frequently displayed on monitors during routine anesthesia. We wanted to study the effects of major changes in metabolism, ventilation and circulation on P(I-ET)O2. |
9451572 | Design and implementation of a PC-based data acquisition system for measuring ECG and respiratory signals. | A PC-based system capable of measuring R-R intervals in the electrocardiogram and detecting respiration phases is presented. It consists of standard amplifiers for ECG and respiration signals and a puter that detects plexes, inspiration and expiration using low-pass, high-pass and differentiation processes. The performance of the method is evaluated using an application for real ECG and respiratory data. |
9451573 | Auscultation revisited: the waveform and spectral characteristics of breath sounds during general anesthesia. | Although auscultation monly used as a continuous monitoring tool during anesthesia, the breath sounds of anesthetized patients have never been systematically studied. In this investigation we used digital audio technology to record and analyze the breath sounds of 14 healthy adult patients receiving general anesthesia with positive pressure ventilation. Sounds recorded from inside the esophagus pared to those recorded from the surface of the chest, and corresponding airflow was measured with a pneumotachograph. The sound samples associated with inspiratory and expiratory phases were analyzed in the time domain (RMS amplitude) and frequency domain (peak frequency, spectral edge, and power ratios). There was a positive linear correlation (R2 > 0.9) between inspiratory flow and sound amplitude in the precordial and esophageal samples of all patients. The RMS amplitude of the inspiratory and expiratory sounds was approximately 13 times greater when recorded from inside the esophagus than from the surface of the chest in all patients at all flows (p < 0.001). The peak frequency (Hz) was significantly higher in the esophageal recordings than the precordial samples (298 +/- 9 vs 181 +/- 10, P < 0.0001), as was the 97% spectral edge (Hz) (740 +/- 7 vs 348 +/- 16, P < 0.0001). In the adult population esophageal stethoscopes yield higher frequencies and greater amplitude than precordial stethoscopes. Quantification of lung sounds may provide for improved monitoring and diagnostic capability during anesthesia and surgery. |
9451574 | Respiratory sinus arrhythmia during anaesthesia: assessment of respiration related beat-to-beat heart rate variability analysis methods. | Beat-to-beat heart rate variability analysis is a powerful tool for the diagnosis of neuropathy. Respiration-related heart rate variability (respiratory sinus arrhythmia, RSA) reflects the function of parasympathetic nervous system during spontaneous ventilation while awake. RSA is also claimed to monitor the depth of anaesthesia. Power spectrum analysis or various averaging techniques of the heart rate variability are usually applied. The current literature, however, does not usually interpret the ground rules and limitations of the method used, and this may sometimes lead to erroneous conclusions on the data. The aim of our study was pare and analyse critically the performance of different methods of evaluating RSA during anaesthesia and positive pressure ventilation. Power spectrum analysis, the root mean square of the successive RR-interval difference (RMSSD), and two respiration related methods, RSA index and average phase RSA, were included in parison. To test these methods, 11 patients were anaesthetised with isoflurane and their lungs were ventilated mechanically with a frequency of 6 cycles min-1. Each patient received a bolus dose of atropine (20 micrograms kg-1) during the trial. Electrocardiogram, electroencephalogram and tracheal pressure signal from respirator were recorded and analyses were performed off-line. We demonstrated that general indices, such as RMSSD, may be strongly affected by heart rate level and other non-respiration related variations in heart rate. We also showed that the effect of unwanted fluctuations on RSA can be reduced with respiration dependent beat-to-beat methods. Furthermore we confirmed that in addition to the amplitude, also the pattern of respiratory sinus arrhythmia is of interest: the pattern is reversed in pared to spontaneous breathing while awake, as we have shown earlier. To analyse RSA during anaesthesia, we mend the use of an average phase RSA method based on beat-to-beat variability that shows both the amplitude and pattern of RSA. Finally, no measure of RSA should be used without a presentation of the actual beat-to-beat heart rate curve. |