Horst Michna

Learn More
Bisphenol A [BPA; 2,2-bis-(4-hydroxyphenyl)-propane] is a monomer used in the manufacture of resins with a wide range of applications, e.g. plastic coatings in the food packaging industry. BPA has been shown to have a weak oestrogenic activity in vitro and in vivo. Despite its low oestrogenic potency there is concern that, as a consequence of slow(More)
The rat uterotrophic assay is a widely used screening test for the detection of estrogenic, endocrine-disrupting chemicals. Although much attention has been paid to identifying protocol variables and reproducibility between laboratories the question whether toxicodynamic and toxicokinetic variations of different strains may affect their sensitivity to(More)
The function of the uterus is regulated by female sex steroids and it is, therefore, used as the classical target organ to detect estrogenic action. Uterine response to estrogens involves the activation of a large pattern of estrogen-sensitive genes. This fact offers the opportunity to analyze the estrogenic activity of xeno- and phytoestrogens, and the(More)
The phytoestrogen genistein was studied in normal and malignant experimental uterine models in vivo. The action of genistein on the uterus and vagina of ovariectomized DA/Han rats after 3 day oral administration (25, 50 or 100 mg/kg/BW/d) was compared to ethinyl oestradiol (0.1 mg/kg/BW/d). Effects on uterine and vaginal morphology, uterine growth and(More)
There is increasing evidence that induction of apoptosis by antihormones is an important mechanism in regard to their growth inhibitory action on hormone dependent tumors. In this report we have compared the efficiency of tamoxifen (Tam) and the pure antiestrogen ICI 182780 (ZM) to induce apoptosis in the estrogen dependent breast cancer cell line MCF‐7.(More)
A novel concept – the hygiene-based margin of safety (HBMOS) – is suggested for the assessment of the impact of potential endocrine modulators. It integrates exposure scenarios and potency data for industrial chemicals and naturally occurring dietary compounds with oestrogenic activity. An HBMOS is defined as a quotient of estimated daily intakes weighted(More)
The aim of the present study was to examine the effects of 8 weeks of exercise training on the fatty acid composition of phospholipids (PL) and triacylglycerols (TG) in rat liver, skeletal muscle (gastrocnemius medialis), and adipose tissue (epididymal and subcutaneous fat). For this purpose, the relevant tissues of 11 trained rats were compared to those of(More)
In the presented study, we have analysed effects of the environmental estrogens bisphenol A (BPA), p-tert-octylphenol (OCT), o,p'-DDT (DDT) and coumestrol (COU) on cell proliferation, apoptosis induction, progesterone receptor (PR) and androgen receptor (AR) mRNA expression and ER alpha protein expression in comparison to estradiol (E2) and the selective ER(More)
Macrophages of humans could be extracted in large numbers from the connective tissue using a newly developed, not particularly difficult method. These macrophages were compared with the peritoneal macrophages of mice using light-, scanning and transmission electron-microscopic methods. The sterility of the cell suspension and the high yield of macrophages(More)
Numerous epidemiologic studies revealed that ethnic populations with higher dietary intake of phytoestrogens have the lowest incidence for breast cancer. The molecular mechanisms which may be responsible for this cancer protective action of phytoestrogens are so far only barely characterised. There are some hints that phytoestrogens may act like selective(More)