Dynamics of testosterone concentration in male steppe lemmings (<Emphasis Type="Italic">Lagurus lagurus</Emphasis>) in the reproductive cycle reflects the species-specific mating system

In the blood of male steppe lemmings, relatively low background levels of testosterone were detected, this is characteristic of a monogamous species. A significant increase in testosterone level, more expressed in sexually active males, was observed at the initial stage of formation of reproductive couples. Apparently, in the future, the couple will exist in a stable relationship, and, hence, the maintenance of a high testosterone level becomes excessive. The decrease in, and the relative “normalization” of, the hormone level during the existence of the pair, including raising of the young, promotes higher expression of the male paternal care of the offspring at the species level.     

Ultrastructural characteristics of autorosette formation in vivo

The interaction of extravascular erythrocytes with lymphocytes, macrophages, polymorphonuclear leucocytes and fibroblast like cells in human gastric ulcer and in post-ulcer scar was studied by means of electron microscopy and cytochemical methods. It was shown that such interaction results in autologous rosette formation. There were also autorosette in the capillaries where autorosette forming cells were endothelial cells and lymphocytes. Many kinds of autorosette forming cells were connected with some peculiarities of ulcer process in the stomach.