Effect of Adrenomimetics and Serotonin on Polypotent Stromal and Hemopoietic Precursors in Cytostatic Myelosuppression

Pharmacological Analysis of the Therapeutic Effect of Radioprotectors Cystamine and Indralin in the Capacity of Radiomitigators

The therapeutic radiomitigating effect of cystamine and indralin was studied in experiments on mice and rats and pharmacological analysis of these drugs was carried out. The animals were subjected to whole-body ⁶⁰Co γ-irradiation. The mice were exposed to single (9-10 Gy) or double (8 Gy) irradiation with an interval of 1 month. The rats were exposed to 10 Gy with partial shielding of the upper quarter of the abdomen. In experiments on mice, pretreatment with reserpine abolished the therapeutic effect of cystamine administered repeatedly every 15 min over 1 h after irradiation. Moreover, summation of the radioprotective and therapeutic effects of the radioprotector was revealed under these conditions. In mice and rats, α₁-adrenoreceptor blocker terazosin did not abolish the therapeutic effect of indralin administrated after irradiation, but blocked the radioprotective effect of indralin applied prior to irradiation. At the same time, 5-HT₂ serotonin receptor blocker tropoxin abolished the therapeutic effect of indralin without affecting its radioprotective activity.

Ultrastructurural picture of cyclophosphamide-induced damage to the liver

We studied the ultrastructural reorganization of hepatocytes and other populations of liver cells after cyclophosphamide treatment. Single administration of cyclophosphamide was followed by significant ultrastructural changes in two major populations of liver cells (hepatocytes and sinusoidal endothelial cells). This treatment was also accompanied by reactive changes in Kupffer cells, lymphocytes, and plasma cells migrating into the spaces of Disse. Cyclophosphamide-induced spatial reorganization of hepatocytes was associated with a progressive decrease in the structural density of mitochondria, significant reduction of the smooth endoplasmic reticulum, and increase in autophagocytosis (e.g., sequestration of glycogen). Intracellular reorganization of endothelial cells was related to the following two factors: damage (necrobiosis) of some cells; and increase in metabolic processes, phagocytosis, and regenerative reactions in other cells.