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Biomedical subjects

M Weber

Publications and source records attributed to M Weber.

At least 451 records · Page 25Linked to original sources
PubMed1994

[Herpetic meningoencephalitis in the elderly. Apropos of 13 cases].

In a retrospective analysis of 13 cases of Herpes simplex encephalitis (mean age: 67.2 +/- 6.4 years; ten women, three men), the authors conclude that this infection is more often due to Herpes simplex virus 1 in the elderly. Diagnosis is difficult at an early stage, and must be suspected in case of confusion (9/13), especially feverish (11/13), associated with neurological signs (10/13), and particularly epilepsy (5/13). It requires a lumbar puncture which collect a clear and lymphocytic fluid. Prognosis of this encephalitis depends on early diagnosis and an presumptive therapy with acyclovir. EEG is helpful showing periodic activity (10/13). CT scan and MRI can show unspecific abnormalities, but often too late. Laboratory findings will secondarily confirm the diagnosis quite frequently, using new Elisa methods. Polymerase chain reaction allows earlier diagnosis. Geriatric cases seem more often due to reinfection or to endogen virus reactivation rather than to primary infection.

Aged↗
PubMed1994

COL4A5 gene deletion and production of post-transplant anti-alpha 3(IV) collagen alloantibodies in Alport syndrome.

Mutations in the COL4A5 gene encoding the alpha 5(IV) chain of type IV collagen have been implicated as the primary defect in X-linked Alport syndrome. Several kinds of mutations have been reported so far, spanning point mutations to complete gene deletions. About 5% of Alport patients, who undergo renal transplantation, develop anti-glomerular basement membrane (GBM) nephritis, causing loss of allograft function. In one such patient, COL4A5 gene deletion was recently identified. In the present study, the GBM constituent, targeted by the anti-GBM alloantibodies from the patient who had complete COL4A5 gene deletion was identified. Its identity was determined on the basis of circulating antibody binding to various GBM constituents, domains of bovine type IV collagen and recombinant NC1 domain of human type IV collagen. These results establish, for the first time, the absence of the alpha 5(IV) chain in Alport GBM and, in the same patient, the production of an alloantibody that is targeted to a different chain of type IV collagen, the alpha 3(IV) chain. These findings provide further support for the hypothesis that: (1) anti-alpha 3(IV) collagen alloantibodies mediate the allograft glomerulonephritis; and (2) COL4A5 gene mutations cause defective assembly of the alpha 3(IV) collagen alloantibodies mediate the allograft glomerulonephritis; and (2) COL4A5 gene mutations cause defective assembly of the alpha 3(IV) chain in Alport GBM, as reflected by the production of anti-alpha 3(IV) alloantibodies.

Basement Membrane↗
PubMed1994

Facial recognition in hypothetically schizotypic college students. The role of generalized poor performance.

This study investigated facial and facial affect recognition abilities among hypothetically schizotypic college men, defined by high scores on the perceptual aberration, magical ideation, and schizotypy scales. Groups were commensurate in age, handedness, and general intelligence. Multiple analyses of variance revealed that high-scoring subjects, relative to control subjects, made more errors on a facial affect recognition task (F = 5.32, p < .05) and on a facial recognition task (F = 8.5, p < .01). Additional multiple analyses of covariance using the face recognition scores as the covariant found no group differences. These results extend similar findings in schizophrenic individuals to hypothetically schizotypic college students, and suggest that both groups exhibit affect recognition deficits that reflect generalized attention and vigilance deficits rather than a specific emotion recognition deficit.

Adult↗
PubMed1994

Ultrastructural and immunohistochemical studies in callitrichid renal glomeruli.

The "normal" mesangium of callitrichids exhibits certain features pointing to enhanced activity. Protrusions of the mesangial cellular cytoplasm (blebs) into the capillary lumen were observed very frequently as were electron-dense granules in mesangial matrix channels. Histochemical, alpha-actin expression was invariably observed in the mesangial cells of callitrichids.

Actins↗
PubMed1994

Hepadnavirus P protein utilizes a tyrosine residue in the TP domain to prime reverse transcription.

Hepadnavirus DNA minus strands are covalently linked at their 5' terminus to the viral P gene product, which has been taken to indicate that the hepadnaviral polymerase polypeptide itself also functions as a protein primer for initiating reverse transcription of the RNA pregenome. The present study confirms this indication by identifying the nucleotide-linked amino acid in the P protein sequence of the duck hepatitis B virus (DHBV). In a first set of experiments, mutational analysis of three phylogenetically conserved tyrosine residues in the DNA terminal (TP) domain indicated that of these, only tyrosine 96 was essential for both viral DNA synthesis in transfected cells and priming of DNA synthesis in a cell-free system. This assignment was confirmed by direct biochemical analysis: tryptic peptides from the DHBV P protein, 32P labelled at the priming amino acid by the initiating dGTP and additionally labelled internally by [35S]methionine, were isolated and analyzed in parallel to reference peptides synthesized chemically and 33P labelled by a tyrosine kinase. Mobility in high-performance liquid chromatography, as well as the release in stepwise amino acid sequencing of phospholabel and of [35S]methionine, identified the priming amino acid unequivocally as the tyrosine in the sequence 91KLSGLYQMK99, which is located in the center of the TP domain. Conserved sequence motifs surrounding Tyr-96 allow the prediction of the priming tyrosine in other hepadnaviruses. Weak sequence similarity to picornavirus genome-linked polypeptides (VPgs) and similar gene organization suggest a common origin for the mechanisms that use protein priming to initiate synthesis of viral DNA genomes or RNA genomes from an RNA template.

Amino Acid Sequence↗
PubMed1994

NO donor SIN-1 protects against reoxygenation-induced cardiomyocyte injury by a dual action.

It was investigated whether morpholinosydnonimine (SIN-1), which spontaneously decomposes into NO and 3-morpholinoiminoacetonitrile (SIN-1C), can be used for protection of cardiomyocytes against reoxygenation-induced hypercontracture. Isolated ventricular cardiomyocytes (from adult rats) were used as the experimental model. SIN-1 [concentration with half-maximal effect (EC50) 2.5 x 10(-4) M] and SIN-1C (EC50 8.3 x 10(-3) M) inhibited the contractile response of electrically paced cardiomyocytes. When the cells were submitted to substrate-free anoxia (135 min) and subsequent reoxygenation (30 min), the onset of reoxygenation provoked their hypercontracture. It was studied whether the temporary presence of the test agents during the last 15 min of anoxia and the first 15 min of reoxygenation prevented hypercontracture. At 10 nM, SIN-1 prevented hypercontracture in 96% of the cells and SIN-1C in 72% of the cells. The protective effect of SIN-1 was reduced to that of SIN-1C by simultaneous presence of methylene blue (50 microM). Methylene blue had no influence on the protective action of SIN-1C. SIN-1C (10 mM) plus sodium nitroprusside (another NO donor, 250 microM) provided the same degree of protection as SIN-1 (10 mM). The results show that reoxygenation-induced hypercontracture can be prevented or attenuated by the temporary presence of high concentrations of SIN-1 or SIN-1C. SIN-1 acts through a dual mechanism, protecting through the generation of NO and SIN-1C.

Adenosine Diphosphate↗
PubMed1994

Improved visual evoked potential latencies in poorly controlled diabetic patients after short-term strict metabolic control.

OBJECTIVE: To determine whether short-term strict control of blood glucose can improve abnormal visual evoked potentials (VEPs) in poorly controlled diabetic patients with no overt diabetic complications. RESEARCH DESIGN AND METHODS: VEPs (P100 wave latencies) were recorded in 12 poorly controlled diabetic patients (7 with insulin-dependent diabetes mellitus and 5 with non-insulin-dependent diabetes mellitus) before and after at least 3 days of near normoglycemia obtained by continuous subcutaneous insulin infusion (CSII). Exclusion criteria were overt diabetic neuropathy or retinopathy. The control subjects were 12 healthy subjects matched for age and sex. Fifty-two other subjects formed a reference control population. The intra-individual coefficient of variation for P100 latency was < 3%. RESULTS: The P100 latencies were longer in diabetic patients than in control subjects (means of both eyes +/- SD: 116.8 +/- 10.1 vs. 106.2 +/- 4.5 ms, P < 0.01), and 4 of the 12 diabetic patients had abnormal VEPs. After 3 days of close blood glucose control (mean blood glucose profile fell from 13.7 +/- 2.2 mmol/l to 6.8 +/- 1.2 mmol/l, P < 0.01), the mean P100 latencies were significantly shorter (112.5 +/- 7.6 ms, P < 0.01) but were still significantly longer than control values. The longer the initial P100 latency, the greater the decrease after CSII. There was no correlation between the fall in blood glucose and improvement in VEPs. CONCLUSIONS: Short-term blood glucose normalization is associated with improved P100 wave latency in uncomplicated diabetic patients. These data suggest that abnormal VEPs are partly reversible and include functional disturbances related to glucose metabolism.

Adult↗
PubMed1994

[Quality assurance in surgery].

Since 1990 the Surgical Department of the Kantonsspital Schaffhausen has been taking part in a quality assurance program organized by the "Bundesland Baden-Württemberg". The traceroperation "appendectomy" will be used to demonstrate the principle of quality assurance and our results for the years 1991 and 1992 will be presented.

Appendectomy↗
PubMed1994

Serum circulating ICAM-1 levels are not useful to indicate active vasculitis or early renal allograft rejection.

During inflammation, activated vascular endothelial cells and other cell types express various adhesion molecules which facilitate binding of circulating leukocytes. Serum concentration of circulating adhesion molecule ICAM-1 (c-ICAM-1) is supposed to reflect the degree of this activation. In order to evaluate the usefulness of c-ICAM-1 serum levels for assessment of disease activity in various vasculitic disorders, we examined 23 patients with systemic lupus erythematosus (SLE, n = 9). Wegener's granulomatosis (WG, n = 6), Goodpasture syndrome (GP, n = 6) and microscopic polyarteritis (MP, n = 2). Disease activity was defined by clinical criteria and by conventional laboratory data. Circulating ICAM-1 concentrations were measured during periods of active clinical vasculitis and on clinical remission. In a second part of the study, we examined whether or not c-ICAM-1 might be helpful in diagnosing acute allograft rejection early after kidney transplantation. After cadaveric kidney transplantation thirteen patients were included. Serum probes were gathered firstly after transplantation, secondly at time of histologically proven allograft rejection and finally after successful anti-rejection therapy and restored transplant function. c-ICAM-1 levels in healthy volunteers (n = 10) were 270 +/- 47 ng/ml (mean +/- SD). Patients with active vasculitis had mean serum levels of 509 +/- 71 ng/ml (SLE), 594 +/- 118 ng/ml (WG), 472 +/- 126 ng/ml (GP) and 498 ng/ml (MP) (mean +/- SD). In clinical remission, mean serum concentrations were found to be 500 +/- 99 ng/ml (SLE), 597 +/- 84 ng/ml (WG), 782 +/- 163 ng/ml (GP) and 594 ng/ml (MP) (mean +/- SD).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Course and prognosis of anti-basement membrane antibody (anti-BM-Ab)-mediated disease: report of 35 cases.

Anti-basement membrane antibody (anti-BM Ab) mediated disease is reported to be a rare disorder frequently leading to severe deterioration of renal function. It was our purpose to work out parameters necessary to predict the outcome reliably and to examine, who will benefit most from therapy. Data from 35 patients were evaluated retrospectively. Diagnosis was based on the detection of linear IgG staining (n = 28) along the glomerular basement membrane (GBM) in renal biopsies and/or on the demonstration of anti-BM Ab both by ELISA and immunoblotting (n = 35). Patients were followed up for at least 6 months. Several variables were analysed as to whether they are appropriate prognostic factors. Twenty patients (57%) presented with Goodpasture's syndrome, 13 (37%) had anti-GBM glomerulonephritis alone, whereas two patients suffered solely from pulmonary haemosiderosis. Frequent initial symptoms were haemoptysis (n = 18), haematuria (n = 26), proteinuria (n = 26) and elevated serum creatinine (n = 27). Among all, 10 patients improved, having stable renal function. Twenty-one patients developed end-stage renal failure and four died. Parameters indicating a poor prognosis were a serum(s)-creatinine greater than 600 mumol/l and crescent formation in more than 50% of the glomeruli on renal biopsy. By combining these two parameters the outcome could be reliably predicted. The initial antibody titre and cigarette smoking were without predictive value. In conclusion, the earlier therapy starts, the better will be the result. Patients presenting early with a serum creatinine < 200 mumol/l and without severe glomerular alterations gained the most benefit from therapy, indicating that outcome may be improved by early diagnosis.

Adult↗
PubMed1994

[X-shaped macular hemorrhage disclosing mixed occlusion of the cilioretinal artery and central retinal vein].

A case of a stellate hemorrhage of the macula occurring in a young man is reported. Analysis of this rare clinical entity allowed us to link it to combined occlusion of the central retinal vein and cilioretinal artery. With regard to this case and to a review of the literature, clinical and angiofluorographic features of this syndrome are recalled. The usually good prognosis of this disease was not observed in our case. Finally, the controversial pathophysiological data are discussed.

Adult↗
PubMed1994

[Capsulorhexis and manual extracapsular extraction of the crystalline lens. Theoretical and practical considerations].

Four cases of inadvertent intracapsular lens delivery secondary to zonular lysis occurring during planned manual extracapsular cataract extraction were reported. Theoretical and practical considerations were presented based on these observations and literature review. These considerations would suggest relaxing incisions when capsulorhexis and planned extracapsular cataract extraction are associated.

Aged↗
PubMed1994

[Assessment of the relationship between trauma and meniscal lesions].

Until the 1930s all meniscal lesions were considered to be of traumatic origin. The efforts of Magnus and his pupils led to a more differentiated medicolegal interpretation of wear and tear of the meniscus and classification of at least some types of meniscal lesions as nontraumatic in the sense of accident insurance. This caused controversy, continuing to the present day, as to whether trauma or degeneration is essential for a meniscal tear. This debate can now be closed. Numerous investigations of meniscus pathology have proved that the isolated, essentially traumatic meniscal tear does not exist. Only if the viscoelastic properties of meniscus tissue are changed may indirect force cause a rupture. There is no longer any reason to follow principles for the assessment of meniscus damage differing from those for tendon or intervertebral disc lesions. Only penetrating joint injuries or joint fractures may lead to a direct meniscal lesion (corresponding to penetrating spine trauma or vertebral body fracture with concomitant disc lesion). Separation of the meniscus from its insertion is the analog of discoligamentous spinal trauma. Post-traumatic meniscus degeneration due to joint instability is equivalent to the instability of the motion segment with intervertebral disc degeneration. Isolated meniscal tears and isolated intervertebral disc ruptures cannot be caused by indirect force. The conventional, inconsistently applied criteria to distinguish traumatic and degenerative meniscal lesions are no longer necessary.

Biomechanical Phenomena↗