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Biomedical subjects

G Schmidt

Publications and source records attributed to G Schmidt.

At least 163 records · Page 9Linked to original sources
PubMed1994

Quantitative western blotting using [gamma-33P]ATP and the ultrasensitive bio-imaging analyzer.

This report describes a method for simultaneous quantitative determination of antigens from protein blots based on the highly sensitive "contact-copy" procedure, applying the phosphorylation reaction as a general detection principle. Using ultrasensitive bio-imaging analyzer systems permits us to quickly and easily quantify single bands directly from the picture screen and to achieve a high-resolution printing of the image (pictography). By applying a new kanamycin loading procedure it is possible to use phosphocellulose paper P81 as a substrate matrix. Replacing 32P with 33P as a detection isotope leads to an improvement of the sensitivity, resolution, and safety. The method is applied to analyze the proteins dystrophin, myosin, vinculin, and desmin from human tissue lysates. The high sensitivity of the procedure (detection limit approximately 1 pg dystrophin) permits determination of the quantity of dystrophin in very small tissue biopsy samples, which is of special interest for Duchenne/Becker muscular dystrophy diagnosis.

Adenosine Triphosphate↗
PubMed1994

[Insurance medicine in routine forensic medicine].

When the forensic doctor is confronted with a query coming from the insurance medicine, he will perhaps realize, that he has suddenly reached the boundaries of his knowledge. Statutory regulations are partly not yet available and partly contested. This accounts for the fact, that sometimes ten or more expert opinions are formulated for one and the same litigation. In the present paper some themes are randomly selected and reviewed in accordance with scientific findings. Investigated with references pertaining to current points at issues, are the following controversial subjects: a) Victim compensation law b) Nursing insurance law c) Transplantation law d) Acceleration trauma e) Lightning casualties f) Heroin (drug criminality) g) Age determination h) Insurance fraud The practice shows, that the physician's need to search for causality is restricted by juridical thought, be it by legal enactments or by the superior courts' guiding principles.

Disability Evaluation↗
PubMed1994

Method for simultaneous determination of the distribution of capillary plasma flow and myocyte redox state (NADH-fluorescence) in the hypoperfused myocardium of the anesthetized rat.

A method is described which allows to observe the pattern of capillary plasma filling simultaneously with the redox state (NADH-fluorescence) of the myocytes in the hypoperfused myocardium. In anesthetized rats the coronary perfusion pressure was reduced to a defined level, the blood plasma labeled with dye-conjugated albumin and a myocardial biopsy-sampled. Freeze-substitution of histological sections allowed to detect the intravascular plasma label as well as the myocyte NADH-fluorescence on a microscopic level. It was found that areas showing increased cellular NADH-fluorescence did not arise in a distribution congruent with zones of failing capillary plasma flow in the hypoperfused myocardium.

Anesthesia↗
PubMed1994

The saluretic effect of the thiazide diuretic bemetizide in relation to the glomerular filtration rate.

The effect of the thiazide diuretic, bemetizide, on the excretion of Na+, K+, Cl-, Ca2+, and Mg2+ in relation to the glomerular filtration rate (GFR) was studied in 17 subjects whose creatinine clearances ranged from 133 to 5 ml.min-1. After a 2-day fluid and salt balanced control period, 25 mg bemetizide given orally induced natriuresis and kaliuresis which lasted for 24 h and were proportional to the GFR of the patients. The ratio of bemetizide-induced K+/Na+ excretion was always 0.17 irrespective of individual GFR. In renal failure, bemetizide increased the fractional Na+ excretion from 3% to about 10%. Kaliuresis was associated with magnesiuria, whereas bemetizide-induced calciuresis was insignificant. The thiazide reversibly lowered GFR in all subjects.

Adult↗
PubMed1994

Changes in adolescents' sexuality between 1970 and 1990 in West-Germany.

Based on two studies (using semistructured interviews) of 16- and 17-year-old West German urban adolescents, the first in 1970 (N = 602) and the second in 1990 (N = 415), this paper traces the changes in young people's sexual behavior and attitudes during the past two decades: (i) The marked trend in the 1960s towards having coitus and petting at an ever earlier age does not seem to have continued; the changes noted in the incidence of heterosexual experiences since 1970 are minimal. (ii) Boys feel themselves less at the mercy of their sexual urges than they used to and tend to link sexuality with love and a steady relationship more than they did 20 years ago; there was a similar though less pronounced change among girls. (iii) Girls now get less pleasure and satisfaction out of sexual encounters, and in heterosexual situations take the initiative and control more than they used to. (iv) There is no evidence that the problem HIV/AIDs had a marked influence on the changes described. Results of the comparative studies are discussed in the context of current developments in man/woman relationships and the debate on gender issues.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Bacteriophages specifically recognizing the lipopolysaccharide antigens O4, O5, O6, and O7 of Escherichia coli.

Four bacteriophages recognizing the Escherichia coli lipopolysaccharide (LPS) antigens O4, O5, O6, and O7, respectively, were isolated from pooled sewage samples. Electron microscopic investigations revealed icosahedral phage structures. Phages phi O4, phi O5, and phi O7 belonged to Bradley's morphology group C, while phi O6 had a tail and resembles phages of group A of Bradley. The nucleic acid of the phages was identified as double-stranded DNA of different genomic sizes. Host range studies showed that only E. coli strains with homologous O antigens were attacked. No lysis of encapsulated and rough E. coli strains was observed. The phages specifically depolymerized the homologous LPS of their host strains; they may be useful for detecting respective non-capsulated E. coli strains in epidemiological studies as simple alternative to the laborious serological typing. Diagnostic application is restricted, however, as strains carrying K antigens have not been detected. The high specificity of the phage-associated enzymes provides a mild method for the preparation of oligosaccharides from the LPS for structural studies.

Bacteriophages↗
PubMed1994

A simple procedure to demonstrate the presence of the O-antigen capsule in enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli O111 bacteria very often produce a capsule-like polysaccharide exhibiting the same chemical composition as the O-specific chains of their lipopolysaccharide and being designated as O-antigen capsule. In this paper, a new simple procedure is described for the detection of this capsule polymer. O-antigen capsule polysaccharide and lipopolysaccharide of bacterial extracts were electrophoretically separated in agarose cetavlon gel, blotted onto nitrocellulose membranes and visualized by immunological methods. As a result of this procedure, the O-antigen capsule can be detected as a spot completely separated from the LPS (Figs. 1 and 2). Consequently, this method allows a clear discrimination of K+ and K- strains.

Agglutination↗
PubMed1994

Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters.

The effects of peppermint oil and eucalyptus oil preparations on neurophysiological, psychological and experimental algesimetric parameters were investigated in 32 healthy subjects in a double-blind, placebo-controlled, randomized cross-over design. Four different test preparations were applied to large areas of the forehead and temples using a small sponge and their effect was evaluated by comparing baseline and treatment measure. The combination of peppermint oil, eucalyptus oil and ethanol increased cognitive performance and had a muscle-relaxing and mentally relaxing effect, but had little influence on pain sensitivity. A significant analgesic effect with a reduction in sensitivity to headache was produced by a combination of peppermint oil and ethanol. The essential plant oil preparations often used in empiric medicine can thus be shown by laboratory tests to exert significant effects on mechanisms associated with the pathophysiology of headache.

Administration, Topical↗
PubMed1994

Bacterial endotoxin: molecular relationships of structure to activity and function.

Endotoxins of Gram-negative microbes fulfill as components of the outer membrane a vital function for bacterial viability and, if set free, induce in mammalians potent pathophysiological effects. Chemically, they are lipopolysaccharides (LPS) consisting of an O-specific chain, a core oligosaccharide, and a lipid component, termed lipid A. The latter determines the endotoxic activities and, together with the core constituent Kdo, essential functions for bacteria. The primary structure of lipid A of various bacterial origin has been elucidated and lipid A of Escherichia coli has been chemically synthesized. The biological analysis of synthetic lipid A partial structures proved that the expression of endotoxic activity depends on a unique primary structure and a peculiar endotoxic conformation. The biological lipid A effects are mediated by macrophage-derived bioactive peptides such as tumor necrosis factor alpha (TNF). Macrophages possess LPS receptors, and the lipid A regions involved in specific binding and cell activation have been characterized. Synthetic lipid A partial structures compete the specific binding of LPS or lipid A and antagonistically inhibit the production of LPS-induced TNF. LPS toxicity, in general, and the ability of LPS to induce TNF are also suppressed by a recently developed monoclonal antibody (IgG2a), which is directed against an epitope located in the core oligosaccharide. At present we determine molecular and submolecular details of the specificity of the interaction of lipid A with responsive host cells with the ultimate aim to provide pharmacological or immunological therapeutics that reduce or abolish the fatal inflammatory consequences of endotoxicosis.

Animals↗
PubMed1994

Reconstruction of blood flow distribution in the rat kidney during postischemic renal failure.

Inner medullary blood flow has been found to remain nearly unchanged during postischemic renal failure, despite a severely disturbed perfusion in the outer medulla. In order to elucidate this discrepancy, rats were subjected to 1 h left renal artery occlusion and 1 h reflow. The blood plasma was then labeled by dye-conjugated globulin for 1 min. The in vivo indicator distribution was histologically analyzed, especially in the medullary vascular bundles. The filling there was observed along a section plane positioned through the inner stripe along the long and the short axis of the organ. Vessels centrally located within the bundles were more labeled than those in the periphery of the bundles. In addition, the degree of filling on the whole was almost twice as high in the tissue near the renal sinus as in the central area. At the same time, filling defects in the renal papilla were restricted mostly to the center of that tissue. The observations support the assumption that differences in blood flow obstruction exist within each bundle. They also show that perfusion defects of the outer medulla occur more readily in the center of the organ, thus allowing blood to enter the inner medulla via vascular bundles located marginally, adjacent to the renal sinus of the kidney.

Animals↗
PubMed1994

Release of 17-beta-oestradiol from a vaginal ring in postmenopausal women: pharmacokinetic evaluation.

Oestrogen-containing vaginal rings of various designs have been utilised in hormone replacement therapy. In contrast to the traditional 'homogeneous' design, rings designed with a steroid-containing core and outer polymer sheath provide a diffusion-controlled release rate which enables the delivery of low doses of drug. The aim of this investigation was to evaluate in vitro oestradiol release from a 'core' designed vaginal ring (Estring) and furthermore, to establish the in vivo concentration-time course of oestradiol, oestrone and total oestrone (unconjugated plus conjugated) in consecutive applications of such an oestradiol-containing vaginal ring in postmenopausal women. Results indicate that the controlled release design of Estring produces stable, low systemic plasma concentrations of oestradiol and has an extended time period of release.

Administration, Intravaginal↗