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Biomedical subjects

M Weber

Publications and source records attributed to M Weber.

At least 433 records · Page 24Linked to original sources
PubMed1995

[Comparative study of four commercialized serologic methods for the diagnosis of gastric Helicobacter pylori infection].

OBJECTIVE: Four commercially available enzyme-linked immunosorbent assays (ELISA) were evaluated for serological diagnosis of Helicobacter pylori (H. pylori) infection in 79 untreated patients. METHODS: Infection has been diagnosed in 40 patients, in whom culture and/or urease test and histopathology from antral biopsies, were positive for H. pylori. RESULTS: Sensitivity (Se) and specificity (Sp) of these tests, calculated with indeterminate serological results (9 patients) classified as positive (ind +) or negative (ind -), were not statistically different: GAP-test (Bio-Rad), Se = 95% (ind +), 90% (ind -), Sp = 84.6% (ind +), 89.7% (ind -); Pylori-Stat (Biowhittaker), Se = 97.5% (ind + or -), Sp = 71.8% (ind +), 71.9% (ind -); Premier H. pylori (Biomedical Diagnostics), Se = 92.5% (ind +), 90% (ind -), Sp = 84.6% (ind +), 81.2% (ind -); Cobas-Core (Roche), Se = 92.5% (ind + or -), Sp = 76.9% (ind +), 79.5% (ind -). There was a strong correlation between mucosal inflammation and H. pylori status. Discrepancies between infectious status and at least one serology result were observed in 16 patients (11 H. pylori negative and 5 H. pylori positive patients). CONCLUSION: These 4 tests are of equivalent diagnostic value. Thus, the selection of one of them should take into account cost and practicability.

Adolescent↗
PubMed1995

[Normolipemic plane xanthoma, monoclonal gammopathy, anti-lipoprotein activity, hypocomplementemia].

INTRODUCTION: Normolipaemic plane xanthomatosis is classically associated with a monoclonal gammapathy. CASE REPORT: We observed this association in a 69-year-old woman. This case was particular since anti-lipoprotein activity due to a monoclonal IgG immunoglobulin was found in the serum with abnormal complement fractions. The paraproteinaemia remained stable after a 2-year follow-up. CONCLUSION: This association is remarkable. The anti-lipoprotein activity of the monoclonal protein should be emphasized in light of the immunological processes involved in the pathogenesis of this association.

Aged↗
PubMed1995

[Atrial electrophysiological study of unexplained ischemic cerebrovascular disorders].

The aim of this study was to search for the presence of atrial vulnerability by programmed atrial stimulation in patients with unexplained ischaemic cerebrovascular strokes and to evaluate the effects of intravenous flecainide acetate on the electrophysiological parameters and on the induction of atrial arrhythmias. Thirty-eight patients (20 men, 18 women) with a mean age of 38.4 +/- 11 years were investigated. Programmed atrial pacing triggered a sustained (> 1 min) atrial arrhythmia with 1 or 2 extrastimuli in 23 of the 38 patients (61%), in these patients, there was a significant shortening of the effective refractory periods (ERP: 193 +/- 23 vs 218 +/- 30 ms; p < 0.02) and of the functional refractory periods (FRP: 228 +/- 25 vs 253 +/- 27 ms; p < 0.01) with lengthening of the A2 auriculogramme (99.7 +/- 22 vs 76.1 +/- 16 ms; p < 0.05). A combined study of the refractory periods and conduction defects provides a means of calculating an index of latent vulnerability which is greatly shortened when an atrial arrhythmia is induced (2 +/- 0.5 cm vs 3 +/- 0.6 cm; p < 0.001). Atrial arrhythmias could not be initiated after intravenous 3 mg/kg of flecainide acetate in 4 subjects (17%) with initially positive atrial stimulation tests. This study confirms the high frequency of atrial vulnerability in patients with unexplained ischaemic cerebrovascular strokes. In their population, the authors observed a low efficacy of flecainide acetate in the prevention of reinduction of atrial arrhythmias. The indication of long-term antiarrhythmic drugs in these patients are questionnable and should be assessed by a prospective long-term multicentre trial.

Adult↗
PubMed1995

Short technical reports. Effects of lipopolysaccharide on transfection efficiency in eukaryotic cells.

The suitability of different purification methods for preparation of plasmid DNA for transfection into eukaryotic cells was systematically investigated. The reporter plasmid, pRSVcat, was prepared using several methods, and residual impurities in the preparations were quantitated. Transfection with these preparations was performed with several cell lines (HeLa, Huh7, COS7 and LMH) and two transfection methods: liposome-mediated and calcium phosphate transfection. Transfection efficiencies were determined by measuring chloramphenicol acetyltransferase expression. Higher transfection efficiencies were obtained with plasmid preparations of higher purity (those prepared by anion-exchange chromatography or two rounds of CsCl-gradient centrifugation) than with preparations of lower purity (those prepared using a silica-based DNA adsorption method or a single round of CsCl centrifugation). The results also demonstrated specifically that increasing concentrations of lipopolysaccharides in plasmid preparations directly correlate with decreasing transfection efficiencies.

Adsorption↗
PubMed1995

[Preservation of kidney transplants with a modified UW solution--initial clinical results].

Although the University of Wisconsin (UW) has become the standard solution for the preservation of kidneys for transplantation, the importance of the colloid hydroxyethylstarch (HES), one of the key compounds of the UW solution, has been judged controversial. It has been shown in various experimental models that dextran-40 may successfully substitute for HES. Dextran-40 is not only cheaper but also has a variety of biological effects which may be beneficial during the graft reperfusion phase. The aim of this clinical study was to examine the efficiacy of dextran-40 based preservation solution (Dex-PS) for its use for human kidney graft preservation and to compare the transplantation results with kidneys preserved with UW solution. A total of 87 kidneys were preserved with Dex-PS and matched with 87 kidneys preserved with UW solution. Both groups were comparable in terms of donor and recipients characteristics. Patient survival and graft survival after 1 year was 95% and 86% for the Dex-PS group and 94% and 90% for the UW group, respectively (p = n.s.). Primary non-function, delayed graft function, postoperative need for dialysis, and follow-up of serum creatinine were statistically comparable between these two groups. We conclude that dextran-40 can safely replace HES in the UW solution for the purpose of human kidney preservation for transplantation. There were no statistically detectable differences in graft performance between the kidneys preserved with UW and those preserved with Dex-PS.

Adenosine↗
PubMed1994

Beta-adrenergic activation and memory for emotional events.

Substantial evidence from animal studies suggests that enhanced memory associated with emotional arousal results from an activation of beta-adrenergic stress hormone systems during and after an emotional experience. To examine this implication in human subjects, we investigated the effect of the beta-adrenergic receptor antagonist propranolol hydrochloride on long-term memory for an emotionally arousing short story, or a closely matched but more emotionally neutral story. We report here that propranolol significantly impaired memory of the emotionally arousing story but did not affect memory of the emotionally neutral story. The impairing effect of propranolol on memory of the emotional story was not due either to reduced emotional responsiveness or to nonspecific sedative or attentional effects. The results support the hypothesis that enhanced memory associated with emotional experiences involves activation of the beta-adrenergic system.

Adult↗
PubMed1994

[5 leprosy cases in the 20th century in Switzerland].

Leprosy had a great impact on everyday life during the Middle Ages, which is reflected in many works of art and also in some preserved buildings. Worldwide, leprosy is still an unsolved problem; this fact has led the World Health Organization to develop a specific strategy to fight the disease. For physicians in Europe, leprosy has lost its significance. In the archives of the Swiss Canton of Valais leprosy in the 20th century is documented by photographs and written records. It is deplorable to see how a young woman can become crippled, lose her eyesight and die within a couple of years. Probably a pocket of leprosy persisted since the Middle Ages in this remote mountain area. The limited contagiousness of the disease is astonishing, since only a few of the closest family members and inhabitants of the some house were infected, while others remained healthy. The social situation of these patients at the beginning of this century was pitiable. The federal laws on epidemics of 1886 did not mention leprosy, as no one seemed to believe in its existence in Switzerland. Even after the cases of leprosy in the Canton of Valais were revealed, the reaction of the political authorities was reserved. An engaged effort by the involved physicians was necessary to establish the appropriate hygienic measures. In the literature of the time there were regular reports of cases in people who emigrated from the endemic areas. Today, in Switzerland one case of leprosy is discovered per year; thus, leprosy is still a disease which physicians must cope with.

History, 19th Century↗
PubMed1994

Long-term interleukin-6 administration stimulates sustained thrombopoiesis and acute-phase protein synthesis in a small primate--the marmoset.

Interleukin-6 (IL-6) has been ascribed significant roles in both hematopoiesis and the immune response, although its contribution to host defence as a whole is poorly understood. Because short-term IL-6 treatment was previously shown to stimulate megakaryocytopoiesis, we investigated the effect of long-term administration of IL-6 on megakaryocytopoiesis and other systemic parameters in nonhuman primates. We chose a small primate, the marmoset (Callithrix jacchus), which enabled long-term administration at high doses. Recombinant human IL-6 (rhIL-6) administered at doses of up to 1,000 micrograms/kg/d over 4 and 9 weeks caused a sustained twofold to threefold increase of thrombocyte counts, peaking at 4 weeks. Thrombocyte counts declined thereafter, despite continuing IL-6 administration. The number of bone marrow megakaryocytes at 4 and 9 weeks was not increased compared with controls, but the ploidy grade was augmented, suggesting that IL-6 effects are restricted to mature megakaryocytes in vivo. An acute-phase protein response was observed within 24 hours after the first IL-6 administration and reached a maximum after 1 week of IL-6 administration at 25 micrograms/kg. Serum C-reactive protein, haptoglobin, and ceruloplasmin were increased, whereas albumin and transferrin levels declined. The acute-phase protein response was not associated with any morphologic evidence of hepatocellular damage. The increased levels of Ig and soluble IL-2 receptor in the serum levels reflected systemic immunostimulation. There was no evidence of renal mesangioproliferative pathology. Antibodies against rhIL-6 developed within 2 weeks, continuously increasing during the course of the study. High titers of neutralizing antibodies appeared concomitantly with the decrease in platelet counts and decline in acute-phase proteins. Therefore, despite the pleiotropic effects of IL-6 observed in vitro, long-term administration of IL-6 caused a selective and sustained stimulation of thrombopoiesis in marmosets that was only ablated by the appearance of neutralizing antibodies, and high doses were well tolerated in marmosets. A long-term targeting of IL-6 to cells of the megakaryocytic lineage, without evoking general toxicity, confirms the potential therapeutic usefulness of rhIL-6 for the chronic treatment of thrombocytopenic patients.

Acute-Phase Proteins↗
PubMed1994

[Gonorrheal arthritis].

A 43-year-old female patient presented with migratory arthralgias, generalized exanthema and arthritis of the left elbow. She had a history of fever and chills three days earlier. Beside to a maculopapular and pustular rash and a joint involvement we found a swelling of the dorsal surface of her right hand without wrist effusion or synovitis. The clinical presentation was typical for the diagnosis of disseminated gonococcal infection (arthritis-dermatitis syndrome). Arthrocentesis was performed, and the cultures of the synovial fluid on chocolate agar were positive for Neisseria gonorrhoeae. The serologic examination for gonococcus was negative, it became positive some weeks later. The therapy with intravenous penicillin G 6 x 10(6) units/day for ten days was successful; unfortunately, we could not treat the partner. The present case report is illustrated with colour prints and describes the typical clinical picture of a diagnosis which is nowadays rare or even forgotten.

Adult↗
PubMed1994

Properties of voltage-activated Na+ and K+ currents in mouse hippocampal glial cells in situ and after acute isolation from tissue slices.

In the present study, we were interested in a quantitative analysis of voltage-activated channels in a subpopulation of hippocampal glial cells, termed "complex" cells. The patch-clamp technique in the whole-cell mode was applied to identified cells in situ and to glial cells acutely isolated from tissue slices. The outward current was composed of two components: a sustained and a transient current. The transient K+ channel had electrophysiological and pharmacological properties resembling those of the channel through which the A-currents pass. In addition, this glial A-type current possessed a significant Ca2+ dependence. The current parameters determined in situ or in isolated cells corresponded well. Due to space clamp problems in situ, properties of voltage-dependent Na+ currents were only analysed in suspended glial cells. The tetrodotoxin (TTX) sensitivity and the stationary and kinetic characteristics of this current were similar to corresponding properties of hippocampal neurons. These quantitative data demonstrate that at an early postnatal stage of central nervous system maturation, glial cells in situ express a complex pattern of voltage-gated ion channels. The results are compared to findings in other preparations and the possible consequences of transmitter-mediated channel modulation in glial cells are discussed.

Animals↗
PubMed1994

Arthroscopy of the knee without pathological findings.

From 1983 to 1990, 82 knee arthroscopies (8.2%) carried out in our patients found nothing pathological. Sixty-four percent of these patients were active in sports, but trauma was noted in 32% of the cases only. Football and other ball games, skiing, and track and field athletics were the main causes. Twenty-six percent of the patients had undergone previous surgery in the affected knee. At a mean of 4.6 years postoperatively, clinical and radiological re-assessment was conducted so as to compare our pre- and intraoperative findings with the further course of events. We found that 48.2% of the patients were symptom-free after the diagnostic arthroscopy, 37.5% had persistent discomfort and 14.3% had a recurrence of discomfort after 6 months to 2 years. The objective measurement score (Zarins Rowe score), at 47.5 out of 50 points, was better than the subjective score, at 40 out of 50 points. Our diagnoses had to be changed retrospectively: meniscal lesions were diagnosed too frequently, while chondropathia patellae and instability were often missed. Additionally, complaints could be related to abnormal axis, limited range of motion of the hip or knee, leg length inequality and hypermobility. Being unable to verify a presumed intra-articular lesion arthroscopically is frustrating for both doctor and patient. Our data suggest that meniscal signs should be looked at more critically and emphasise the need for a complete evaluation of the whole locomotor system.

Adolescent↗