Microtubules: strange polymers inside the cell.

This paper provides a consistent approach (within a one-dimensional approximation) to the description of the evolution of the microtubule length at both low- and high-density concentrations. We derive general master-type equations which are based on the key chemical reactions involved in the assembly and disassembly of microtubules. The processes included are: polymerization and depolymerization of a single protein dimer, catastrophic disassembly affecting an a piori arbitrary number of dimers, and a rescue event. Solutions of the derived equations are compared with the existing experimental data. Important conclusions linking the emergence of bell-shaped histograms with the nature of catastrophe and rescue phenomena are drawn. Finally, we briefly discuss the emergence of coherent phenomena in microtubule polymerization, i.e., a transition to collective oscillations in the assembly and disassembly effects.

Models of assembly and disassembly of individual microtubules: stochastic and averaged equations.

In this paper we present solutions of the master equations for the microtubule length and show that the local probability for rescues or catastrophes can lead to bell-shaped length histograms. Conversely, as already known, non-local probabilities for these events result in exponential length histograms. We also derive master equations for a stabilizing cap and obtain a new boundary condition which provides an explanation of the results obtained in dilution and cutting experiments.

[Interpretation of the estrogen receptor content of breast cancer]. / Zur Interpretation des Ostrogenrezeptorengehaltes in Mammakarzinomen.

The biochemical analysis of estrogen receptor (ER) content, using the DCC (dextran-coated charcoal) method, was compared with different plotting methods of the estrogen-receptor immunocytochemical assay (ER-ICA) in 80 primary breast cancers including 9 metastases under routine conditions. It was evident, that the determined content of estrogen receptors depends on the technique of measurement, as well as the microscopic organizations of the individual carcinomas and should be interpreted in respect of their content of stroma and if possible of tumour heterogeneity.

[Representative studies of the vitamin D status of 2-year-old children in Frankfurt am Main]. / Repräsentative Untersuchungen zur Vitamin-D-Versorgung zweijähriger Kleinkinder in Frankfurt/M.

In a representative sample population of 421 two-year-old Frankfurt children studied for vitamin-D nutritional status, only one case of subclinical rickets was discovered. 93.3% of the children have been a regular vitamin-D supplements during the first 12 month of life, but only 32.7% of them continued to receive the supplement beyond the age of one year. Risk groups were not identified, neither with regard to ethnic groups, nor smaller vitamin-D doses, or any other aspect.

[Microkymography--a method to measure the flow velocity in the microvascular bed after endotoxin administration (author's transl)]. / Die Mikrokymographie--eine Methode zur Objektivierung der Geschwindigkeit in der terminalen Strombahn bei Endotoxinwirkung.

In this paper the application of intravital microkymography on studies of the microcirculation of the hamster cheek pouch is presented. Flow velocity reduction which is one of the characteristic initial alterations in small blood vessels after injection of endotoxin is recorded in a direct way by the strip microkymography. The method of the recording system is described and some examples of the effects of endotoxin as well as of serotonin, one of the mediators of endotoxin, are given. The advantage of microkymography in quantitative and functional studies of endotoxic actions, e.g. flow velocity decreases and vessel diameter changes, is discussed.