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M Kohlmeier

Publications and source records attributed to M Kohlmeier.

48 records · Page 3Linked to original sources
PubMed1982

Effects of estrogens and progestogens on lipid metabolism.

Because the incidence of venous thromboembolism, coronary heart disease, and stroke is increased in users of oral contraceptives (OCs), the possible causal metabolic side effects of OCs have been widely investigated. In this article we present epidemiologic data associated with OC use. Total plasma triglycerides and cholesterol levels were elevated in OC users while high-density lipoprotein cholesterol levels were lowered. Another section discusses some hormone-dependent physiologic and pathophysiologic aspects of lipid metabolism. Finally, we report on the isolated influence of estrogens and progestogens and their interrelation, including some recent findings about the effects of different progestogens on lipoproteins.

Adolescent↗
PubMed1981

Analysis of progress curves in enzyme kinetics: bias and convergent set in the differential and in the integral method.

Two problems encountered in the analysis of progress curves are examined: 1. Systematic deviations due to errors in the initial solute concentrations make the least-squares method unsuitable. The improvements accomplished by the introduction of a proper weighting matrix are investigated. 2. Non-linear parameter optimization implies a dependence of the optimized parameters on their initial estimates, due to the existence of multiple minima. It is shown that the sensitivity of the optimized parameters on the initial estimates is reduced by fitting the slopes of the progress curves. A subsequent fit of the original progress curve data is recommended for refinement of the parameters.

Enzymes↗
PubMed1977

Mechanism of action of D-glyceraldehyde-3-phosphate dehydrogenase.

A computer approximation with polynomial quotients was used to evaluate from experimental data the dependence of the initial velocity of D-glyceraldehyde-3-phosphate dehydrogenase reaction on the concentration of substrates. The initial velocity values were determined at optimum conditions, over a wide range of substrate concentrations and by interpolating the time curve of enzyme reaction as t leads to 0. A further computer approximation with polynomial quotients, without any implied hypothese, gave the best fit to the experimental results. The analysis of this final equation shows that two types of catalytic sites may exist. Due to the complexity of the system, the results are compatible either with the ordered binding or with rapid equilibrium random binding of substrates to each separate, but interacting type of sites. Previous experimental data showing the formation of abortive and dead-end complexes can be interpreted as kinetic effects, inherent in the mechanism. Results at variance with earlier data can be explained by the different experimental conditions.

Computers↗