[Indralin--a novel effective radioprotector during irradiation by high-energy protons].

Experiments with 120 mongrel dogs were aimed at the assessment of radio protective strength of indralin and local shielding of the pelvic marrow from 2.5 Gy, and also their concurrent use for the dogs irradiated by protons (240 MeV) at absolutely lethal and over-lethal 4 Gy and 5 Gy. Clinical observations, hematological investigations and ECG analysis of survived animals were conducted 4.5 years post the irradiation. Dogs that remained healthy following 3.5 to 4.5 years since the irradiation were sacrificed for pathomorphological investigations. The radioprotective effect of local shielding against 4 Gy was weak while this effect of intramuscular indralin (10, 20, 40 mg/kg of body) was significant reaching 50 to 67.7%. The concurrent use of two methods had, apparently, potentiated the 100% radioprotection of the animals irradiated by overlethal 5 Gy. Blood investigations of the survived dogs every 2-4 months evidenced that complete recovery of the total leukocyte count had taken 9 to 13 months. Also, dogs' pregnancy in 9-10 months since the beginning of irradiation pointed to maintenance of fertility and the ability to parturiate 2 or 3 times yielding 5-6 live cubs. Necropsy of the dogs did not reveal gross macroscopic structural changes of visceral organs or tissues. Seven out of 27 sacrificed dogs had benign tumors infrequent in intact dogs at this age.

[Combined effects of prolonged hypokinesia and ionizing radiation on the hematopoietic system and lymphatic organs of rats]. / Kombinirovannoe vozdeistvie dlitel'no i gipokinezii i ioniziruiushchego izlucheniia na sistemu krovetvoreniia i limfoidnye organy krys.

During interplanetary missions ionizing radiations blended with other debilitating non-radiation environmental agents which can modify the radiobiological effect make up a risk factor. Still, the experimental data about the direction of the modifying action are conflicting and diverge from an increase to a depression of radioresistance. In this work we investigated the influence of prolonged hypokinesia on early radiobiological effects. The experiment was conducted with Wistar rats exposed to acute gamma-radiation at a dose of 7.5 Gy after 25 days of head-down immobilization. In the period of one month since exposure the morphological properties of peripheral blood and bone marrow, cell composition and mass of thymus, spleen and adrenal masses have been investigated. A significant, 1.5-2-fold, inhibition of recovery rate was displayed by each sprout of the blood-forming and especially thymolymphatic systems (2.5-3 folds) resulting from combined stress, whereas the depth of radiation damage in terms of maximum degree of the bone marrow tissue depopulation, cytopenia of peripheral blood and mass losses of lymphoid organs was of little difference in the two groups.

[The methodology for clinical trials of radiation-protective agents intended for the conditions of manned space flights]. / Metodologiia klinicheskikh ispytanii protivoluchevykh sredstv, prednaznachennykh dlia uslovii pilotiruemykh kosmicheskikh poletov.

The methodology of clinical testing of antiradiation measures to be used in manned space missions is proposed and discussed. The tests should be based on: an individual tolerance to a recommended medicinal form of the drug; the tolerances to the effects of motion sickness, prolonged transverse and longitudinal accelerations; graded physical exercise; evaluation of performance (operator activity).

[Cardiac function and reactivity in the late period following irradiation with high-energy protons]. / Funktsional'noe sostoianie i reaktivnost' serdtsa v otdalennom periode posle oblucheniia protonami vysokikh énergii.

Electrocardiography was used to analyze the results of 4-year investigations of the cardiac activity and reactivity (adrenalin test) in 32 dogs irradiated with high-energy protons (approximately 240 MeV) at absolutely lethal doses of 4 and 5 Gy. The author's and literature data have shown the similarity of cardiac functional features and reactivity in a long-term period in dogs with those in animals after radiation disease caused by exposure to some other types of ionizing radiations.

[Partial shielding of the bone marrow as a method of local protection of the body from the effects of cosmic radiation]. / Ekranirovanie chasti kostnogo mozga kak metod lokal'noi zashchity organizma ot deistviia kosmicheskoi radiatsii.

This paper reviews existing data on bone marrow partial shielding in animal studies with reference to partial-body protection in space radiobiology and medicine. Analysis of reported data indicates the efficacy of the method to protect animals (including dogs) exposed to gamma-radiation and high-energy protons. Experimental findings that demonstrate the effectiveness of bone marrow partial shielding show that this method may be used for partial-body protection in space flight.

[Combined, local and chemical protection of the body against radiation exposure during space flight]. / Kombinirovannaia, lokal'naia i khimicheskaia zashchita organizma ot radiatsionnogo vozdeistviia pri kosmicheskikh poletakh.

This paper summarizes studies of the combined protection of dogs exposed to acute high energy proton irradiation at a dose of 400 rad. The chemical radioprotector--mexamine--was injected intramuscularly at a dose of 10 mg/kg or administered per os at a dose of 75 mg/kg. During the exposure 14.5% of bone marrow was shielded. The dose behind the shielding was 250 rad. The combined use of mexamine administered per os and partial bone marrow shielding provided better protection, whereas either type of protection applied separately proved inefficient.

[Chemical protection of the body against irradiation with high-energy protons]. / Khimicheskaia zashchita organizma pri obluchenii protonami vysokikh énergii.

Comparison of chemical protection against electromagnetic radiations (X- and gamma-rays) and high-energy proton radiations give evidence that the mechanism of antiradiation effects of radioprotectors and other biological protectors against different radiations is identical. On the basis of the data published in the literature it has been shown that the degree of radiation protection of animals and other biological objects in comparable doses differs insignificantly during exposures to proton and standard irradiations.