[Significance of the intervals of hydroxyurea administration for epithelial damage to the small intestine in mice].

The states of the murine small intestinal epithelium 6, 30 and 78 h after the end of the multiple regular injections of hydroxyurea (HU) were analysed with the aid of the light and electron microscopy. The course of 6 regular injections of 5 mg/mouse HU was begun 24 h after the initiating gamma-irradiation in a dose 200 rad and the interval between injections was varied from 7 to 19 h for different experimental groups of mice. The analysis of the epithelial state revealed two minima of the tissue damage which correspond to the courses of HU injections with the intervals close 9 h and 16.5 h.