[The protective action of nimodipine on the ischemic myocardium]. / K zashchitnomu deistviiu nimodipina na ishemizirovannyi miokard.

The experiments with unconscious cats and dogs have demonstrated that the calcium antagonist nimodipine has a profound anti-ischemic property. The drug reduces the average value of ST-segment elevation in multiple epicardial ECG leads, during acute myocardial ischemia. Nimodipine maintains cardiac pump and contractile functions, elevates ATP levels in the arbitrarily intact and ischemic myocardium of the left ventricle during 40-min occlusion and 60-min reperfusion of the coronary artery. The protective action of the drug is unassociated with enhanced collateral coronary circulation.

[The protective action of vasocyclin (prostacyclin) on the ischemic myocardium]. / Zashchitnoe deistvie vazotsiklina (prostatsiklina) na ishemizirovannyi miokard.

The effect of vasocyclin (prostacyclin) on the blood supply, activity and functional state of the intact and ischemic myocardium was studied in experiments on anesthetized cats. The drug (100, 300 and 500 mg/kg/min) was shown to produce a dose-dependent increase of the coronary blood flow, systolic and cardiac outputs, an enhancement of the myocardial contractile function, a lowering of arterial blood pressure. Under acute occlusion of the coronary artery vasocyclin improves the functional state of the myocardial ischemic focus, stabilizes the contractile and pumping functions of the heart, exerts the antiarrhythmic action.

[The absence of a parallelism between the antihypoxic and anti-ischemic actions of pharmacological agents]. / Otsutstvie parallelizma mezhdu antigipoksicheskim i protivoishemicheskim deistviem farmakologicheskikh sredstv.

The experiments on different species of animals (mice, cats) showed the lack of parallelism between the antihypoxic and anti-ischemic effects of pharmacological agents. Of four studied antihypoxic agents (lithium oxybutyrate, piracetam, glyo-6, a derivative of pyrimidine S-207) only GABA derivatives showed an increase of the lactate/pyruvate ratio in the blood of the venous sinus under occlusion of the coronary artery and consequently possessed the anti-ischemic properties. Such difference in the effects of the antihypoxic agents on the myocardium was determined to a certain degree by their different influences on the collateral coronary blood circulation.

[The protective action on the myocardium of antihypoxants in acute occlusion and subsequent reperfusion of the coronary artery]. / Zashchitnoe deistvie na miokard nekotorykh antigiposantov v usloviiakh ostroi okkliuzii i posleduiushchei reperfuzii koronarnoi arterii.

In experiments on anesthetized cats with acute occlusion of the coronary artery followed by its reperfusion antihypoxants piracetam, lithium hydroxybutyrate and pyrid oxynyl-glyoxylate (glyo-6) were shown to stabilize the contractile and pumping functions of the heart. GABA derivatives piracetam and lithium hydroxybutyrate in contrast to glyo-6 were found not only to stimulate the compensatory processes in the conventional intact area of the ischemized left ventricle but also improve the energy metabolism in the ischemic focus itself.

[Changes in the number of sister chromatid exchanges in cultured Chinese hamster cells with limited proliferation. Additional studies]. / Izmeneniia urovnia sestrinskikh khromatidnykh obmenov v kul'tiviruemykh kletkakh kitaiskogo khomiachka pri ogranichenii ikh proliferatsii. Dopolnitel'nye issledovaniia.

During "stationary phase ageing" of cultured Chinese hamster cells (B11dii-FAF28 line, 2372a clone), i. e. while decreasing the proliferation rate and in the stationary growth phase the frequency of spontaneous sister chromatid exchanges (SCE) progressively increases (from 2- to 23-day "age"); the frequency of thiophosphamide-induced (1h) SCE increases from 2- to 23-day "age" by the same value as the frequency of spontaneous SCE; the cells deepen into the R-phase of the cell cycle.

[Analysis of the kinetic growth patterns of cultured cells. III. The effect of inoculation density, of a geroprotector-antioxidant and of stationary-phase aging]. / Analiz nekotorykh kineticheskikh zakonomernostei rosta kul'tiviruemykh kletok. III. Vliianie plotnost poseva, geroprotektora-antioksidanta, "statsionarnogo stareniia".

With the help of a previously devised model of cultured cell growth kinetics it was shown that the "plateau" level on the growth curve of human embryo diploid fibroblasts increased, if the cells were grown with Epigid geroprotector-antioxidant (equal results with two drug concentrations: 10(-5) and 10(-7) M, resp.). It was also found that the "plateau" level on the growth curve of cultured "3 days aged" Chinese hamster cells (subcultivated to a fresh medium 3 days after a 1:6 subcultivation) lays higher than the "plateau" level of "14 days aged" cells but lower than that of "7 day aged" cells. Furthermore it was shown that an increase in inoculation density of Chinese hamster cells increased proportionately the rate of cell population growth but had a little effect on the "plateau" level of the growth curve. The data obtained are discussed in terms of some "proliferative" theories of cellular ageing.

[Strengthening of the DNA-protein complex during the stationary aging of cultured cells]. / Uprochnenie DNK-belkovogo kompleksa v protsesse "statsionarnogo stareniia" kul'tiviruemykh kletok.

Accumulation of DNA-protein crosslinks during "stationary phase ageing" (i.e. with the increase of non-proliferating period) of cultured transformed Chinese hamster cells and normal embryonic diploid human fibroblasts was determined by the improved method of column chromatography using hydroxylapatite of 14C-valine, 14C-leucine and 3H-thymidine-labelled cell homogenates. Such an accumulation, however, was not observed during "stationary phase ageing" of xeroderma pigmentosum human fibroblasts. Possible mechanisms of the above phenomenon are discussed.

[Analysis of the kinetic growth patterns of cultured cells. II. The action of ionizing radiation, an alkylating agent and a low-frequency electromagnetic field]. / Analiz nekotorykh kineticheskikh zakonomernostei rosta kul'tiviruemykh kletok. II. Deistvie ioniziruiushchei radiatsii, alkiliruiushchego agents, nizkochastotnogo élektromagnitnogo polia.

With the help of the earlier devised model of cultured cell growth kinetics it is shown that the "plateau" level on the growth curve of Chinese hamster cells decreased proportionally to a dose of the agent applied after a short-term treatment by gamma-radiation or by alkylating agent thiophosphamide. The analysis of our own and literature data enabled us to propose that the lowering of the growth curve may testify to the geropromoter character (i.e. manifesting in ageing promoting) of the investigated factor action. As the low-frequency electromagnetic field induces similar changes in the growth curve, it is related (together with both the above factors investigated) to geropromoters.

[Analysis of the kinetic growth patterns of cultured cells. I. The model]. / Analiz nekotorykh kineticheskikh zakonomernostei rosta kul'tiviruemykh kletok. I. Model'.

On the basis of the Verhulst-Pearl equation, a model of cultured cell growth kinetics is devised. Analysing both authors' and literature data, a possibility was shown to use the model for description of growth kinetics of different cultured cell types. The proposed method of analysis of cell growth kinetic characteristics also provides a rapid evaluation of the cell population doubling time and of the relative number of non-dividing cells in the population.

[Changes in the level of sister chromatid exchanges in cultured Chinese hamster cells undergoing limited proliferation]. / Izmeneniia urovnia sestrinskikh khromatidnykh obmenov v kul'tiviruemykh kletkakh kitaiskogo khomiachka pri ogranichenii ikh proliferatsii.

"Stationary phase ageing" of cultured Chinese hamster cells (when proliferation rate decreases and in the stationary growth phase) produces an increase in the frequency of spontaneous sister chromatid exchanges (SCE). Thiophosphamide-induced (24 h) frequency of SCE increases from 2-day to 5-day "age" and later (in the stationary phase) is practically the same. The "stationary ageing" cultured cells are suggested to be used as a model system for studying molecular-genetic age changes.

[DNA degradation in resting cultured Chinese hamster cells]. / Degradatsiia DNK v pokoiashchikhsia kul'tiviruemykh kletkakh kitaiskogo khomiachka.

A gradual accumulation of the alkali-labile sites in DNA of cultured Chinese hamster cells during "stationary phase ageing" was shown by ultracentrifugation in alkaline sucrose gradients. A possibility is discussed of using the stationary phase mammalian cell cultures as a model for studies of ageing mechanisms.