The effect of ultraviolet radiation of different wave lengths on the concentration of DNA--fuchsin in the cells of Zajdel's ascitic hepatoma]

The cytophotometrical analysis of the relationships between the content of DNA--fuchsin and the duration of acid hydrolysis of the intranuclear DNA (the Feulgen reaction) in the Zaidela hepatoma cells allows to see the degree of the DNA--protein binding. The UV irradiation of different wave-lengths (254, 325 and 365 nm, resp.) irrespective of the degree of absorption by nucleic acids, causes changes in chromatin condensation, thus suggesting the labilization of DNA--protein bounds.     

Correlation analysis in studying the mechanism of action of smooth muscle stimulants]

The presence of correlation between the value of the maximal effects of acetylcholine and other cholinomimetics, as well as serotonin, barium chloride and depolarizing solution was studied on an isolated strip of rat stomach. It was shown that the effect of acetylcholine closely correlated with the effects of other cholinomimetics, to a lesser degree with the effects of barium chloride and depolarizing solution, and least of all with the effect of serotonin. It is proposed to use the degree of this correlation to analyze the point of action of different drugs and processes of coupling the receptor stimulation with the observed effect. It was shown that the point of convergence of the ways of coupling of the three latter influences preceded the convergence of their common way with the way of coupling of the cholinomimetic effects.     

Effects of oxymethacil on microcirculation and neuronal impulse activity in the cat cerebral cortex in acute fosfakol poisoning]

By using the methods of vital microscopy and extracellular registration of the neuronal activity the effect of oxymethacil (OM) on microcirculation and NSA in cat brain cortex was studied after grave poisoning by organophosphate paraoxon. The rapid depression of NSA together with the pronounced disturbances of microcirculation in cortical vessels were showed after intravenous injection of paraoxon (0.8 mg/kg). The prophylactic injection of OM (5 mg/kg) induced protective effect on the studied parameters. This effect was more pronounced when OM injection was combined with the M-cholinolytic amyzyl. The present data show the reasonableness of antioxidants using for the correction of a brain functional condition damaged by organophosphates.     

Kinetics of the antibacterial effect of ampicillin and sulbactam combinations in dynamic and static conditions

Kinetics of antimicrobial effect (AME) of ampicillin/sulbactam combinations (ratios of 4:1 to 1:2) on ampicillin resistant bacterial strains producing beta-lactamases of types II, III, IV and V according to Richmond classification was studied with using the computerized system MS-2 (turbidimetric recording) and an in vitro dynamic model (microcalorimetric recording). The concentrations of the drugs in system MS-2 (static conditions) corresponded to the maximum ones observed in serum of humans after bolus intravenous administration of ampicillin in a dose of 0.5 g and sulbactam in doses of 0.125 to 0.5 g. The pharmacokinetic profiles of the drugs observed in the human serum after their oral and intravenous administration and in the tissue-chamber fluid after intravenous administration of ampicillin (0.5 g) and sulbactam (0.125 g) were simulated in the dynamic model. The combination efficacy was estimated with using the parameter of AME duration (TE) reflecting shifts in the curves of the microbial regrowth in the presence of the drugs against the curve of the control growth (in the absence of the drugs) and the parameter of the AME intensity (IE) evaluated by the area between the curves. It was noted that increasing of the ampicillin/sulbactam ratio from 1:4 to 1:1 was accompanied by an increase in the AME. Further increasing of the sulbactam content in the combination did not result in higher AME. For combined ampicillin/sulbactam dosage forms the ratios of 1:1 to 2:1 should be recommended.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of microelectrophoretic application of GABA on the formation of a cellular analog of a conditioned reaction

Influence of GABA application on ability of sensorimotor cortical neurones to form conditioned cellular reactions was studied in chronic experiments on rabbits. Neuronal reactions were analysed at the initial stage of eye-lid conditioning. GABA application in a period of presentation of paired conditioned and unconditioned stimuli disturbed formation of inhibitory conditioned cellular reactions and did not influence elaboration of activating responses. Plastic changes underlying the process of formation of inhibitory conditioned neuronal reactions are supposed to be of intracortical nature.