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M Schauer

Publications and source records attributed to M Schauer.

27 records · Page 2Linked to original sources
PubMed1981

[Mathematical modelling of glycolysis and of adenine nucleotide metabolism of human erythrocytes. II. Simulation of adenine nucleotide breakdown following glucose depletion].

The breakdown of adenine nucleotides in human erythrocytes in physiological and alkaline medium at 37 degrees C after glucose depletion is simulated by a mathematical model of energy metabolism. The simulation consists of time dependent solutions of a system of 16 differential equations derived from the stoichiometry of chemical pathways and kinetic properties of enzymes. Starting with the stationary characteristics of the model (M. Schauer et al.: Acta biol. med. germ. 40, 1659, 1981) the results of the simulation were analysed as a function of 1) the share of adenylate deaminase in the degradation of adenine nucleotides and 2) the interaction between adenylate kinase equilibrium and magnesium ions. The experimental data and the simulated concentration changes are in good accord, provided that the assumed activity of adenylate deaminase is very low so that the degradation of adenine nucleotides proceeds mainly via AMP-hydrolysis. The extensive activation of adenylate deaminase during incubation is explained by its sigmoid kinetics with respect to AMP. To improve the results of simulation changes in the adenylate kinase equilibrium have to taken into consideration. These have been measured during incubation of erythrocytes; they can be attributed only partly to the increasing concentration of magnesium ions and to differences among the constants of magnesium association to adenine nucleotides.

Adenine Nucleotides↗
PubMed1975

[Problem of scattered light in the localized stimulation of the retina (author's transl)].

In attempting local retinal stimulation of an intact eye the generation of scattered light cannot be prevented, but it can be sufficiently reduced by a suitable selection of stimulus parameters, especially of stimulus luminance and facial field luminance, of stimulus size and exposition time. By investigating the most important sources of scattered light, e.g. inhomogenities in the dioptric media, reflections at refracting surfaces, diffraction at the pupil borders, and the distribution of scattered light in the retina it becomes possible to develop indications for the construction of a focal optical stimulator.

Humans↗
PubMedDate not supplied

[Animal experiment studies on the effect of intra-articular injections of antiphlogistic-antirheumatic agents on articular cartilage in vivo].

Animal experiments have shown that weekly intraarticular injections of various antiphlogistic/antirheumatic drugs into the knee joint induce progressive degenerative alterations in joint cartilage. The observed degenerations and destructions are most similar to the pathophysiology of osteoarthrosis in humans. By X-ray and macroscopic techniques the degenerative processes can be studied qualitatively and quantitatively. A decrease of joint space is a sensitive and early indicator of osteoarthrosis and showed that 10 weeks after intraarticular application of Ibuprofen, Phenylbutazone, Oxyphenbutazone, Flufenamic acid, Niflumic acid, Na-salicylate, Clofezone, Bumadizone and Dexamethasone the degenerative alterations in the injected knee joints were more severe than by applications of Chloroquine,D-penicillamine, Salicylamide and Indometacin. The degenerative effect on articular cartilage by the investigated drugs can be explained by their inhibitory potency on anabolic metabolism of connective tissue. The results of our animal experiments lead to the conclusion, that antiinflammatory drugs may also in man induce or accelerate degenerative joint diseases especially after long term treatment with high doses of these drugs.

Animals↗
PubMedDate not supplied

Contamination of dialysis water and dialysate. A survey of 30 centers.

The concentration of bacteria and endotoxin in dialysis water and dialysate of 30 dialysis centers in western Germany was examined. Water samples were obtained after treatment by reverse osmosis or other processing methods. Collection of dialysis samples for bacterial, fungal, and endotoxin analysis was conducted before and 2 hours after start of hemodialysis. In 17.8% of all water samples analyzed, the AAMI standard was exceeded and bacterial and fungal counts greater than 200 colony forming units/ml were found. In 11.7% of all dialysate samples, higher contamination than the recommendations for dialysate of 2000 colony forming units/ml were found. The concentration of endotoxin in water and dialysate varied between 0 and 95 endotoxin units in the water samples and 0 and 487 endotoxin units/ml in the dialysate samples. In 12.2% of all water sampled, and 27.5% of all dialysate samples, values of 5 endotoxin units/ml were found. No correlation was found between the level of contamination of either water or dialysate in a specific center and the following factors: water processing method (reverse osmosis or others), type of dialysate (acetate of bicarbonate), type of dialysate machine, or method of machine disinfection. In view of these results it is suggested that endotoxin testing, especially in the dialysate, be a part of regular quality control in dialysis.

Bacteria↗
PubMedDate not supplied

Breast preserving surgery decision making.

Mammography, and in special cases MRT, allow the detection of DCIS and microcarcinomas. Breast preserving surgery needs intraoperative care for tumor free margins. Decision making under favourable and unfavourable conditions is discussed. Tumor grading is important with respect to locoregional recurrences. Improvements in breast cancer diagnosis are discussed in a separate paper in the same volume. The significance of c-erbB2 in pT1N0M0 stage has been determined in 472 cases. Within the c-erbB family, c-erbB2 has highest significance. p53 should also be evaluated with respect to tumor progress. In a few cases of malignant cystosarcoma phyllodes, p53 reaction was found in epithelial and mesenchymal cell systems. These results correspond to the results of Domagala et al (90) which show that vimentin positivity correlates with high proliferation, a high degree of malignancy and c-erbB2 positivity. Finally, the significance of angiogenesis with respect to the ineffective knot-formation for tumor cell transport and detachment of epithelia with apoptosis are discussed. The significance of proteolytic activity of cancer according to the results of Schmitt et al (89) is included in the discussion. Biochemical analysis seems to be much more effective for prediction of metastatic process as compared with immunohistochemical evaluations.

Breast Neoplasms↗