[Cytophotometric determination of DNA concentration in the cells of experimental brain tumors. II. Primary tumors of rat cerebellum induced by 9, 10-dimethyl-1, 2-benzanthracene]. / Tsitofotometricheskoe opredelenie soderzhaniia DNK v kletkakh éksperimental'nykh opukholei mozga. II. Pervichnye opukholi mozzhecka krys, indutsirovannye 9 10-dimetil-1, 2-benzantratsenom

The Feulgen-DNA cytophotometry was applied for studies of 31 rat cerebellum tumors induced by 9, 10-dimetyl-1,2-bensantracene. Most of these gliomas (22) were astrocytomas of different grades of malignancy. The histological diagnosis of other tumors was: glioblastoma -- 4, oligoastrocytoma -- 2, oligodendroglioma -- 1, gliosarcoma 1. The majority cells of 26 tumors had diploid or paradiploid DNA quantity, 4 tumors (1 astrocytoma, 3 dedifferentiated astroyctomas) had triploid modal classes. The tetraploid modal class and a large number of polyploid cells were found only once for glioblastoma multiforme. A supposition was made that drastic changes of ploidy could arise for the second time during the process of tumor evolution. The authors failed to show any exact differences in the ploidy of gliomas in rats with athyreosis or hyperthyreosis, and in the ploidy of somatic cells in control animals.

[Mechanism of increased resistance of thyroidectomized rats to the blastomogenous effect of 9,10-dimethyl-1,2-benzanthracene in cerebellum]. / O mekhanizme povyshennoi rezistenntnosti tireoidzktomirovannykh krys k blastomogennomu deistviiu 9, 10-dimetil-1,2-benzantratsena na mozzhechok krys

In rat cerebellum development of tumor, induced by 9,10-dimethyl-1,2-benzanthracene, was accompanied by a gradual increase in concentration of corticosterone in peripheral blood and by a decrease in 5-hydroxytryptophane decarboxylase activity. Experimental athyreosis inhibited development of the tumor in cerebellum (the tumor developed in 80.8% of normothyreotic animals treated with the benzanthracene derivatives; in the athyreotic animals this figure did not exceed 55.7%), decreased the corticosterone concentration in blood and caused a subsequent decrease in the 5-hydroxytryptophane decarboxylase activity in cerebellum as compared with the corresponding values determined in rats with intact thyroid gland. These alterations are considered as possible determinants of increased resistance of thyroidectomized rats to the blastomogenous effect of 9,10-dimethyl-1,2-benzanthracene on cerebellum.

[Kinetics of the organ and tissue distribution of D-alpha-(5 methyl-3H)-tocopherol as a function of the age of animals]. / Kinetika raspredeleniia D-al'fa-(5 metil-3H)-tokoferola po organam i tkaniam v zavisimosti ot vozrastnykh osobennostei organizma zhivotnykh.

Principles of an intertissue distribution of D-alpha(5 methyl-3H)tocopherol were studied depending on ontogenesis of animals. The tissues were divided into three groups via kinetics of the label distribution: tissues responsible for transport and recirculation of the vitamin, tissues-consumers from which the third group was derived--endocrine glands with the maximal rate of the label incorporation within a week. In preadolescent rats the rate of the vitamin consumption was high due to increase in hepato-intestinal recirculation and to optimal conditions of tocopherol intestinal absorption. In ageing rats the rate of the vitamin utilization was decreased as a result of lowering of its absorption in intestine but the vitamin E metabolism was increased in the tissue-consumers considering that the label content was decreased in tissues, the intestinal phase was prolonged two-fold and more as compared with young animals and that excretion of the vitamin metabolites with urine was increased. High level of radioactivity in feces appears to occur because of presence of tocopherol nonabsorbed in intestine.

[Effect of serotonin on the viability of rats with transplanted glioblastoma multiforme]. / O vliianii serotonina na vyzhivaemost' krys s privitoi mul'tiformnoi glioblastomoi.

Mongrel adult albino female rats with multiform glioblastoma transplanted to the right cerebellar hemisphere were given subcutaneous injections of 8 mg/kg of a serotonin-creatine sulphate solution beginning with the 3rd and to the 28th postoperative days. Rats with a tumor inoculated at the same periods and given injections of a physiological saline solution served as controls. The injection of serotonin leads to a significant increase in the survival of rats by 20% as compared to the survival of rats in the control group, but practically has no effect on the life span of sick animals. Consequently, serotonin either produces an antineoplastic effect in which case the animals do not contract the disease, or it has no effect on the tumor so that the animals die of the developing tumor. Study of the tryptophan content in the neoplasm and the 5-OIAA content in urine provides evidence of a disturbed serotonin synthesis and metabolism in these neoplasms.

[Study of different states of iodine metabolism in rats by means of whole-body radiometry]. / Izuchenie razlichnykh sostoianii iodnogo obmena u krys metodom radiometrii vsego tela

The authors present the principal concepts necessary for the use of the method of radiometry of the whole body in studying the iodine metabolism in vivo in the intact and thyroidectomized rats and also in experimental hyperthyroidism resulting from TTH or thyroidin administration. The iodine metabolism indices in euthyroidism and athyroidism in rats proved to be adequate to the corresponding curves of the iodine metabolism indices in healthy persons and those suffering from myxedema. Experimental hyperthyroidism in rats, similarly to hyperthyroidism in man, was characterized by an increase in tissue metabolism of the hormonal iodine. However, it was accompanied by an accelerated clearance of the organism from an excess of thyroid hormones; due to this it could not serve as an adequate model of thyrotoxicosis in man.