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A A Firsov

Publications and source records attributed to A A Firsov.

104 records · Page 6Linked to original sources
PubMed1977

[Nerve-blocking properties of antibiotics].

Comparative data on the neuroblocking activity of antibiotics of various groups in acute experiments on albino mice and narcotized cats are presented. It was found that according to the impairments in the neuro-muscle conductivity the drugs were arranged in the following descending order: polymyxin B, neomycin, gentamicin, streptomycin, lincomycin and kanamycin. The streptomycin derivatives were approximately 2 times less toxic than streptomycin. The problems of the mode of action of the antibiotics on conductivity of excitation in the neuro-muscle synapses are discussed.

Animals↗
PubMed1977

Relationship between the neuromuscular blocking effect of gentamicin and streptomycin and their concentration in blood.

The principle of the analysis of concentration-response relationships is valid in the case if the effective course is defined by a logistic function and the drug distribution is approximated by a two-compartment model. The method of calculation the data to construct the curves describing the dependence of the effect on drug concentration in the central and in peripheral compartments was elaborated. The relations between the concentrations of gentamicin and streptomycin and their peripheral neuromuscular blocking effect were investigated experimentally on cats. The blocking action of both drugs is evident at concentrations higher than the drug serum levels after administration of therapeutic doses, gentamicin being more active.

Animals↗
PubMed1977

[Optimal regime of intravenous administration of lincomycin in osteomyelitis].

The pharmacokinetics of lincomycin in the blood of 8 patients with osteomyelitis was studied on the drug single and uninterrupted intravenous administration in therapeutic doses. It was found that when the antibiotic was administered continuously according to the routine scheme, its therapeutic blood levels were attained only 1.5 hours after the drug infusion. The optimal regimen of lincomycin uninterrupted infusion providing its constant rate in combination with the single intravenous administration was estimated with the help of the constants of the two-compartment model of lincomycin pharmacokinetics. According to the calculations the rate of the antibiotic administration necessary for providing therapeutic levels should be 2.2 mg/kg in complex with the loading dose equal to 5.4 mg/kg. Practical trials showed that intravenous administration of lincomycin with the above regimen remained within therapeutic range already 10 to 20 minutes after the beginning of the drug infusion. Therefore, from the pharmacokinetic point of view the recommended regimen for lincomycin infusion should be considered preferable to that used presently.

Adolescent↗
PubMed1977

[Pharmacology of rifampicin].

The data on pharmacological study of rifampicin prepared at the All-Union Research Institute of Antibiotics are presented. It was found that by its acute toxicity the drug conformed to rifampicin manufactured by "Lepetit (Italy). When it was administered for a prolonged period of time to rats in doses equivalent to the therapeutic ones for humans, the drug had no effect on the cardiovascular system, the function of the liver and kidneys, growth and debelopment of the rats, the pictures of the peripheral blood. When rifampicin was used in doses 4--8 times higher than the therapeutic ones, it sometimes induced a decrease in the erythrocyte count and hemoglobin level, changes in the liver function, a reliable arrest of the rat growth, some changes in the liver and gastric mucosa revealed on histological examination. No allergic properties of rifampicin were observed in guinea pigs of light colour. No differences in the effect of rifampicin of the Soviet, Italian and Polish production were found.

Animals↗
PubMed1976

[Relationship between nephrotixic effect of gentamicin and streptomycin and their blood levels in laboratory animals].

A principle of studying the nephrotoxic properties of drugs under conditions of maintaining their constant levels in the blood and dynamic registration of the nitrogen levels in the urea followed by histological examination of the kidney is proposed. Correlation between the levels of gentamicin and streptomycin in the cat blood during 4-hour infusion and the level of the nephrotoxic effect was found, gentamicin being much more toxic than streptomycin.

Animals↗
PubMed1975

[Use of a 2-part model of i pharmacokinetics of gentaniycin for maintaining a constant blood concentration in infusion intravenous (an experimental study)].

Maintenance of constant antibiotic blood levels within the required ranges may be accomplished with mathematical modelling of the antibiotic pharmacokinetics. The problem solvation was illustrated on gentamicin. The kinetic analysis of the curves of the drug excretion from the blood after a one-moment intravenous administration of the antibiotic to cats provided estimation of the constants for a two-compartment model of its pharmacokinetics. The constant values were used for calculation of the intravenous infusion rate for gentamicin and the load dose value providing attainance and maintenance of the drug blood levels within the required ranges. The experimental testing of the regiments of gentamicin infusion showed satisfactory correlation of the theoretically supposed and practically found antibiotic blood levels.

Animals↗
PubMed1975

[Comparative study of the relationship between the blood concentration of gentamicin and streptomycin and their muscle-relaxing activity].

A mathematical model of relation between the miorelaxant effect value of aminocyclitol antibiotics and their blood levels is proposed. The kinetics of the reduction of the neuromuscle transmission damaged under the action of the drugs was studied in detail in acute experiments with cats treated with gentamycin or streptomycin administered intravenously. The changes in the effect value in time were satisfactorily described by the logistic function. Parallel determination of the blood levels of the antibiotics in the animals provided construction of an adequate model of their pharmacokinetics. Tabulation of the corresponding biexponential equations and logistic functions for the same time intervals during reduction of the neuromuscle transmission provided necessary information for plotting the "effect: concentration" curves. Comparison of the drug levels at which the effect of inhibition of the neuromuscle transmission was equal to 50% of the maximum one, revealed a statistically reliable difference in the miorelaxant activity of gentamycin and streptomycin. A high miorelaxant activity of gentamycin in comparison to streptomycin was also shown on comparison of the average "effect: concentration" curves plotted on the basis of tabulation of the general equations presenting a combination of the logistic and biexponential equations.

Animals↗
PubMedDate not supplied

Relationship between the blood concentration of the drug and its cumulative effect: a pharmacokinetic analysis of the nephrotoxic action of gentamicin and streptomycin.

The general principle of dependence of cumulative effects on drug concentration in the blood is proposed. The registered response is regarded as a result of the dual effect of drug blood level and duration of action. The corresponding experimental design consists in maintaining the serum concentration values at several definite levels and determining the response values for each of them. The constant serum level of the drug could be achieved by means of continuous infusion calculated according to the pharmacokinetic model. This principle was proved in the acute experiments on cats which established a relationship between the nephrotoxic effect of gentamicin and streptomycin on the one hand and their concentration in the serum and duration of action on the other.

Animals↗