[Radiation modulating properties of derivates of 1,4-dihydropyridine and 1,2,3,4,5,6,7,8,9,10-decahydroacridine-1,8 dione]. / Radiomodifitsiruiushchie svoistva proizvodnykh 1,4-digidropiridina i 1,2,3,4,5,6,7,8,9,10-dekagidroakridin-1,8-diona.

First attempt to analyse radiation modifying action of 52 compounds--derivatives of 1,4-dihydropyridine is presented. Many of these compounds have electrodonating and antioxidative activities. Local radioprotective effects of the substances has been studied using experimental model with partial beta- and X-rays exposure of sole skin in rats to doses of 40 and 30 Gy. Comparison of drug effectiveness and chemical structure revealed the changes of activity dependence due to modification of peripheral radicals of 1,4-dihydropyridine ring. Radioprotective and radiosensitizing compounds with general low toxicity have been found. It is suggested to use the most active compounds for the development of medicinal forms for prevention of local skin and mucosal radiation injuries. Positive results have been obtained with dieton a radioprotective compound of the same type, in radiotherapy.

[Antineoplastic effect of glutapyrone in continual gamma-irradiation of rats]. / Izuchenie antikantserogennogo deistviia glutapirona pri khronicheskom gamma-obluchenii krys.

In experiments on rats (290 animals) exposed to chronic gamma-radiation with the total dose of 10.0 Gy it was detected that prescription of synthetic pharmaceutical of the dihydropyridine class--glutapyrone--together with drinking water during 6 months reduced the rate of malignant neoplasms from 26.5% in the control group to 13% in the treated animals. In radiation-exposed rats that received glutapyrone there was a narrowing of spectrum of the emerged neoplasms (connectively-tissual tumors only) as compared to the animals of the radiated control group, where blastomas of epithelium and lymphoid origin were also revealed. Low toxicity of glutapyrone and its anticarcinogenic action show the potential for this preparation to be used in practice.

[Quantitative assessment of acute radiation damage to the crystalline lens]. / Kolichestvennaia otsenka ostrogo radiatsionnogo porazheniia khrustalika.

This paper is an attempt to unify various approaches to the assessment of acute radiation injury of the organ of vision. The development of cataracts was studied on mice subjected to local irradiation of the head at doses: 7, 10, 12, 15, 20 and 25 Gy. A clinical picture of radiation injury of the eye at different x-ray doses at different stages was established during ophthalmological examination using a manual electro-ophthalmoscope (X5). A method of the quantitative assessment of radiation injury of the mouse eye at different radiation doses was proposed using the light transmission factor tau; its experimental value was obtained, values for different clinical stages of cataracts were established. The time course of the development of radiation cataracts in mice subjected to x-ray irradiation in a wide spectrum of doses, was observed; clinical features of the process were revealed. Dose fractionation under the above conditions did not make a protective effect on the lens. Dependence of a degree of lens injury on irradiation dose obtained owing to the use of the light transmission factor tau, was described with the following equation: (formula; see text)

[Features of the intracellular repair of irradiated keratinocytes]. / Osobennosti vnutrikletochnogo vosstanovleniia obluchennykh keratinotsitov.

By means of light and electron microscopy, intracellular reparation has been studied after a local x-ray radiation of the rat paws (7.74 X 10(-1) Ci/kg) using radioprotectors (mexamin, cysteamin, ionol) and other chemical compounds (including membranoprotective ones). Restoration of the intracellular structures after x-ray burns proceeds more slowly and more complexly than reparation of the epidermis as a tissue system. To the slowly repairing intracellular formations belong mitochondria and, especially, internal mitochondrial membrane, as well as intercellular contacts. Under radiation mitochondria increase their volume at the expense of their three-fold swelling. Preliminary treatment of the skin with some of the compounds mentioned above decreases or completely prevents these changes. By means of the membranoactive chemical compounds, as well as by means of the known radioprotectors it is possible essentially to normalize the process of intracellular reparation and physiological regeneration of the ultrastructures, and in some cases, to stimulate reparative processes in them.

[Quantitative evaluation of the protective action of skin protectors]. / Kolichestvennaia otsenka zashchitnogo deistviia nekotorykh protektorov kozhi.

The purpose of research was to study and give a comparative evaluation of cystamine, mexamine, ionol, dimethyl--sulfoxide, eugenic acid, castor oil and cholesterol as skin local radioprotectors. Experiments were made on random-bred albino rats. Skin areas 25 mm2 in size on each paw were irradiated. The exposure dose rate was 5 X 10(-3) A/kg (1160 p/min.), the surface dose 6.5 X 10(-1) and 7.7 X 10(-1) Q/kg (2500 and 3000 P respectively). The time period (in days) of weak and severe erythema, dry and moist desquamations was assessed. The most sensitive "critical" components of radiation response which are open to modification with the help of radioprotectors--severe erythema and moist desquamation were revealed. Mexamine, cystamine and ionol produce the most marked effect. The value of their protective effect is 48.3; 40.1 and 32.3 units respectively. Skin radioprotectors possessing not less than 50% efficacy can be introduced into practice. A search for new radioprotectors should be aimed at the investigation of agents with the efficacy of a reduction of radiation injuries by 70% and more.

[Effect of immunization on the radioresistance of mice to the action of 90Sr]. / Vliianie immunizatsii na radiorezistentnost' myshei pri deistvii 90Sr.

The preliminary immunization with heated Proteus vulgaris culture introduced in a single injection was found to have a positive influence on the resistance of white mice to radiation emitted by incorporated 90Sr. This effect was manifested by an increase in the survival rate and the mean survival time of the animals, as well as by their increased physical endurance, and the stimulation of recovery process in the spleen.

[Effect of various non-radioactive and radioactive chemical compounds on the structure of the spleen]. / Vliianie nekotorykh neradioaktivnykh i radioaktivnykh khimicheskikh soedinenii na strukturu selezenki.

Dynamical changes in the spleen of mice and rats were studied morphometrically and electron microscopically when the animals were given in drinking water radionucleotides in small concentrations (137Cs, 226Ra, 89Sr, 65Zn, Pb(NO3)2, BeCl2, hexamethyleniamine, methylmercurchloride) for 1-2 years. Total doses obtained for a year were 0.3-100 rad. Reactive reconstruction of the organ under radioactive and chemical effects was stated to proceed in three directions: a) hyperplasy of lymphoid tissue; b) enhanced plasmocytogenesis; c) hyperplasy of extramedullar hemopoiesis. Sequence in the appearance of these reactions and doses which produced them were different for every compound. In 1-2 years at large doses (160-200 rad) atrophy, amyloid degeneration of the spleen or signs of leukemia were observed. Disturbance of intercellular contacts and of intracellular regeneration was demonstrated electron microscopically.

A comparative study of changes in immunological reactivity during prolonged introduction of radioactive and chemical substances into the organism with drinking water.

A comparative study of the factors of non-specific protection and specific immunity, allergic and autoallergic reactivity during prolonged introduction into the organism of experimental animals of 6 different radioactive and 7 harmful chemical substances was carried out. Qualitative and quantitative peculiarities were found in the changes in immunological reactivity during exposure of the organism to radionuclides and stable chemical compounds. Impairment of immunity plays a substantial role in the course and outcome of affections provoked by chronic effect of the substances examined.