[Effect of therapeutic administration of purine derivatives on the life span of irradiated animals]. / Vliianie terapevticheskogo primeneniia purinovykh proizvodnykh na prodolzhitel'nost' zhizni obluchennykh zhivotnykh.

Purine derivatives, meradine and ethimizole, are shown to exert a therapeutic effect with respect to survival of rats exposed to 4 Gy radiation. Distinctions in the death rate between the exposed rats and rats treated with meradine and ethimizole are manifested 1 month following irradiation, i. e. at the time of clinical recovery of the exposed body. The preparations used at other te terms are uneffective. It is suggested that purine derivatives increase the regeneration and compensation of radiation lesions at the time of clinical recovery reducing an irreversible component of radiation damage.

Carcinogenesis and ageing--VII. Carcinogenic effect of single total-body X-ray irradiation in young and old female rats.

Female rats aged 3 and 14 months were exposed to single X-ray irradiation at a dose of 4 Gy. Total frequency of neoplasms and that of malignant tumors in the younger age group amounted to 78 or 42%, and in the older age age group to 66 and 31% respectively, while in the corresponding age groups the figures were as follows: 48 or 7% (p less than 0.05). The comparative analysis of the carcinogenic effect of irradiation in young and old rats has revealed that sensitivity of the mammary gland epithelium, ovarian tissue and thyroid epithelium to malignant actions of irradiation decreases with age. The paramount importance in modification of tissue sensitivity to carcinogenic action of irradiation in ageing is suggested to be related to age-dependent changes in the proliferative activity of the target tissues.

[Use of meradin for normalizing catecholamine metabolism in the rat hypothalamus at late periods following irradiation]. / Primenenie meradina dlia normalizatsii obmena katekholaminov v gipotalamuse krys v otdalennye sroki posle oblucheniia.

Meradine administered in a dose of 2 mg/kg during 10 days 10-12 months after irradiation with a dose of 4 Gy normalized the catecholamine metabolism in rat hypothalamus. The content of noradrenaline was restored as early as 24 h and that of DOPA and dopamine, 1 month after the cessation of meradine injection.

[Change in the catecholamine balance of rat hypothalamus at late periods following local irradiation and its correction with etimizol]. / Sdvigi v balanse katekholaminov gipotalamusa krys v pozdnii period posle lokal'nogo oblucheniia i ego korrektsii étimizolom.

A local exposure (15 Gy) of chest caused a disturbance in the metabolism of adrenergic mediators of hypothalamus at later times (1-12 months) after irradiation: this was manifested by a decrease in the noradrenaline level 1 month following irradiation, and by phase changes in the dopamine content and considerable deficiency of deoxyphenylatanine throughout the entire period of observation. The treatment with etymisol normalized the catecholamine balance.

[Use of purine derivatives for normalizing the hypothalamic function of rats subjected to gamma-neutron irradiation]. / Primenenie proizvodnykh purina dlia normalizatsii funktsii gipotalamusa krys, podvergnutykh gamma-neitronnomu oblucheniiu.

In this work, the authors have made an attempt to correct pharmacologically the disorders in the regulatory function of hypothalamus caused by gamma/neutron-irradiation. For this purpose purine derivatives, ethymisol and meradin, were used. These preparations were effective in correcting fully or partially the postirradiation shifts in the balance between the hypothalamus mediators, catecholamines, and their biosynthetic precursor, dioxyphenylalanine (DOPA). In addition, meradin increased the firmness of the bone regenerator in the traumatized extremity of the animal.

[Changes in the circadian rhythm of the hypothalamo-pituitary-adrenal system at lengthy intervals after irradiation]. / Ob izmenenii sutochnogo ritma gipotalamo-gipofiz-adrenalovoi sistemy v otdalennye sroki posle oblucheniia.

The disturbance of circadian rhythm of the hypophysis-adrenal system (e. g. the absence of an evening fall in the corticosterone content of blood) was observed 3, 6 and 12 months after irradiation of rats (1186 X 10(-4) Ci/kg). Similar changes were noted in the control group of animals of the same age after 6 and 12 months. In the exposed animals, however, these changes were more frequent.