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M S Poliak

Publications and source records attributed to M S Poliak.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Standardized nutrient medium for determining the biological activity of antibiotics of the aminoglycoside group].

The possibility of the use of nutrient media containing only salt components in addition to agar-agar in determination of the biological activity of aminoglycoside antibiotics was confirmed. The optimal results were obtained on the medium including ammonium acetate, disubstituted sodium phosphate and agar-agar. Glucose was added to the medium simultaneously with the test microbe. The medium is simple by its composition. It provides satisfactory growth of B. subtilis ATCC 6633 as the test microbe and clear inhibition growth zones of sufficient size. The results of the assay of the biological activity of neomycin, monomycin, streptomycin and kanamycin on the medium of this composition were reproducible.

Agar↗
PubMed1984

[Growth of test microorganisms used in determining antibiotic activity on synthetic nutrient media].

The growth of gram-negative sporulating bacteria and yeast-like fungi used in a microbilogical assay of antibiotic activity was studied on solid synthetic media of simple composition. Their reproduction with the microbial growth of different density was shown to be possible on media containing available and strictly standardized components, such as salts, glucose and disubstituted sodium phosphate. The cultures tested were not similar by their growth requirements.

Anti-Bacterial Agents↗
PubMed1984

[Nutrient medium for determining the biological activity of heliomycin].

It was shown that a nutrient medium containing only salt components except agar-agar could be used for assay of the biological activity of heliomycin. The optimal results were observed on the medium containing ammonium chloride, urea, disubstituted sodium phosphate, glucose and agar-agar. The medium provided satisfactory growth of Bac. subtilis ATCC 6633 as the test culture and formation of clear inhibition growth zones of the sufficient size. The medium is standard and its use allows obtaining reproducible results in assay of the heliomycin biological activity.

Agar↗
PubMed1983

[Standardization of the nutrient medium for determining the biological activity of a number of antibiotics by the diffusion-in-agar method].

The possibility of using 2 variants of a unified nutrient medium containing no Hottinger's broth for determination of the biological activity of a large number of antibacterial antibiotics was shown. The medium provided satisfactory reproducibility of the results. It contained yeast extract as a source of nitrogen. The medium was selected with the method of the fractional factor experiment. Clear inhibition growth zones and the slope of the dose-response curve were used as the criteria for estimation of the optimal medium. The described nutrient medium allowed a 2-time increase in the sensitivity of the method used for determination of the biological activity of neomycin, monomycin, streptomycin, oxytetracycline, chlortetracycline and erythromycin.

Agar↗
PubMed1983

[Aerobic and anaerobic microflora in experimental drug-induced enterocolitis].

The results of studying aerobic and anaerobic intestinal microflora of rabbits with experimental enterocolitis caused by administration of 7-chlor-7-desoxylincomycin are presented. An increased number of E. coli and some other gram-negative bacteria was noted. It was shown that the quantitative and qualitative composition of the obligate anaerobic microflora was changed: the number of cells of the bacteroids, bifidobacteria, peptococci and peptostreptococci resistant to the antibiotic was low, but the number of clostridia cells resistant to the antibiotic was high. On the basis of a thorough investigation the latter cultures were classified as belonging to Cl. butyricum.

Aerobiosis↗
PubMed1982

[Size of the area of test-culture growth suppression with polyene antibiotic diffusion into the infected gel as a function of time].

The process of inhibition growth zone formation due to diffusion of polyenic antibiotics into inoculated gel was studied. Variability of the zone size with time was traced as a continuation of the mathematical model of zone formation described earlier. Differences in the zone size variability are shown in case the drug inactivation level is so low that it may be neglected and in case the drug inactivation level is considered. An equation for determination of the maximum zone size for the latter case is presented. The experimental data qualitatively correlate with the theoretical propositions and may be explained within the frames of the mathematical models used.

Anti-Bacterial Agents↗
PubMed1981

[Kanamycin sulfate and sodium cephazolin pharmacokinetics in experimental strangulation obstruction of the small intestine].

The experimental investigation of pharmacokinetic properties of kanamycin and cephazolin has shown the antibiotic to penetrate well into the blood, lymph, abdominal exudate. Transport of kanamycin in the wall of the strangulated intestine and its mesentery through the lymphatic system and by adsorption from the abdominal exudate is supposed to be possible. Normal concentration of the antibiotic was determined in the tissues around the strangulation zone. The concentration peak of both antibiotics was noted 1 hour after introduction in all the biosubstrates studied which may serve as an orientator for the optimal time of operation.

Animals↗
PubMed1981

[Mathematical model of zone formation taking into account the inactivation of polyene antibiotics diffusing into an inoculated gel].

The procedure for investigation of the inhibition growth zone formation on diffusion of polyenic antibiotics into inoculated gel is presented. The model of strong inactivation is applicable when the drug inactivation is significant during the period of the zone formation and not only during the period of the 2-fold increasing of the number of the test microbe cells. The experimental study on the passive inactivation of polyenic antibiotics, such as levorin, amphotericin B, mycoheptin and nystatin showed that during the period of the zone formation the first 2 antibiotics were inactivated to such a level that their passive inactivation could be considered strong. A case of drug active inactivation with the test microbe cells is discussed. An equation for the specific period of the zone formation with respect to this particular case of the drug strong inactivation was developed. The parameters of the active inactivation were estimated. The results for levorin are in good agreement with some of its physico-chemical properties, i. e. poor solubility and mycella formation.

Anti-Bacterial Agents↗
PubMed1980

[Effect of the extraction methods and drug form components on the determination of gramicidin C in buccal tablets].

The effect of solvents, extraction procedures and separate components of the troche mass on the results of biological activity determination of gramicidin S with the agar-diffusion method was studied. It was found that irrespective of the solvent and the number of extractions only 76--81 per cent of the antibiotic were determined in the troches. Fruit essence and sugar had a significant effect on the results of gramicidin S biological activity determination as compared to the other components of the dosage form. When accessory substances included in the troches were added to the standard solution, the values of their biological activity were close to the calculated ones.

Agar↗
PubMed1980

[Mathematical model of the zone formation in polyene antibiotic diffusion in an inoculated gel].

A mathematical model of inhibition growth zone formation on diffusion of polyenic antibiotics in gel is described. Dynamic equations for the zone formation describing the changes in time of the microbial population density (test microbe) in the presence of the diffusing antibiotics, as well as equations for diffusion of the antibiotics with an account of their inactivation were developed. Extreme cases of no inactivation of the drug by the test microbe are discussed. For the cases of spontaneous inactivation of the drugs due to instability of their molecules there were developed expressions showing correlation between the zone size and antibiotic initial concentration in the hole and other parameters characterizing the antibiotic and test microbe.

Antifungal Agents↗
PubMed1977

[Characteristics of the action of antibiotics in an experimental process caused by Cl. histolyticum].

The cells of Cl. histolyticum isolated from the muscular tissue of albino mice infected with the microbe and treated with oxyglucocycline or cephaloridin were similar to each other and the cells of the initial strain with respect to their morphological features, growth character on liquid and solid media and saccharolytic activity. The strains isolated from the animals treated with oxyglucocycline were characterized by lower gelatinolytic, hemolytic, caseinolytic and (to a less extent) collogenolytic activity. The strains isolated from the animals treated with cephaloridin slightly differed from the initial strain by their cultural properties. The lethal effect of the total toxin of both variants of the strains studied were similar, only the time of the animal's death being different. The data of the study may serve as one of the explanations of various effects of the antibiotics differing in their modes of action on the microbial cell in cases of infection caused by Cl. histolyticum.

Animals↗
PubMed1977

[Pharmacokinetics of lincomycins in experimental staphylococcal sepsis].

Pharmacokinetics of lincomycin hydrochloride and 7-chlor-7-desoxylincomycin hydrochloride (chlolincocin) was studied on albino mice and rabbits with experimental staphylococcal sepsis caused by intravenous introduction of highly pathogenic cultures. The septic process was accompanied by impairement of the kidney function, the pathological changes in the kidneys being most pronounced. The antibiotic levels in the blood and tissues of the internal organs, i.e. liver, kidneys, lungs and spleen increased in the infected animals, while the content of the antibiotic in the urine decreased. Determination of the plasmatic, kidney and extrakidney clearance revealed the increasing role of the extrakidney clearance. The shudy of the concentrations of 7-desoxylincomycin in the bile of the animals subjected to cholecystostomy showed that the role of the liver in elimination of lincomycin increased in the animals with experimental staphylococcal infection. As the state of the animals improved the changes in the pharmacokinetics of lincomycin decreased.

Animals↗
PubMed1976

[Effect of the physiological activity of Clostridium cells on their sensitivity to antibiotics].

Actively multiplicating cells of C1. perfringens proved to be more sensitive to 7-chlor-7-desoxylincomycin and rifampicin than the cells in the phase of the population dying. The bactericidal effect of the antibiotics on Clostridia vegetating at a temperature range within 37--4degrees was studied. Determination of the content of higher fatty acids in the cultivation medium with the method of gas chromatography showed that the metabolic processes in the bacterial cells went on at a temperature of 4degrees. Sensitivity of Clostridia to antibiotics at 20 and 4degrees lowered. However, all antibiotics inhibited the cell viability under such conditions. The inhibitors of the intracellular protein synthesis, i. e. rifampicin, 7-chlor-7-desoxylincomycin and morphocycline proved to be most active. The effect of beta-lactame antibiotics, i. e. cephaloridine and benzylpenicillin was reliable though lower.

Anti-Bacterial Agents↗