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Biomedical subjects

S M Navashin

Publications and source records attributed to S M Navashin.

At least 19 recordsLinked to original sources
PubMed1995

[Comparative in vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antibiotics with respect to staphylococci and pneumococci].

Antibiotic susceptibility of 225 Staphylococcus strains and 42 Pneumococcus strains was assayed with the method of serial microdilutions. Methicillin resistant Staphylococcus strains (S. aureus and coagulase negative strains) were characterized by high susceptibility to cephalosporins and ampicillin + sulbactam combination, as well as to ciprofloxacin, rifampicin and vancomycin (70 to 100 per cent of the susceptible strains). Less than 50 per cent of the strains was susceptible to erythromycin. The methicillin resistant Staphylococcus strains preserved their high susceptibility to vancomycin and rifampicin (the coagulase negative strains also preserved their susceptibility to ciprofloxacin). Four Pneumococcus strains with the intermediate resistance to benzylpenicillin were isolated (for 9.6 per cent of the strains the MIC was 0.12 to 1.0 micrograms/ml). The growth of 2 out of these 4 strains was inhibited by the ampicillin + sulbactam combination in a concentration of less than 0.5 micrograms/ml and by cefotaxime and the cefoperazone + sulbactam combination in a concentration of less than 1.0 micrograms/ml. The growth of the other 2 strains was inhibited by betalactams in concentrations higher than the above mentioned.

Ampicillin↗
PubMed1995

[Comparative effectiveness of rifampicin for parenteral administration and internal dose in the treatment of experimental plague in albino mice].

The therapeutic effects of parenteral and oral rifampicins were studied comparatively in a model of experimental plague of albino mice infected subcutaneously and by aerosol. The study showed that in a dose of 25 mg/kg rifampicin was highly efficient in the treatment of the albino mice with experimental glandular plague when the drug was administered either parenterally or orally for 7 days (100-percent survival). The parenteral rifampicin was advantageous when used in lower doses (6.25-12.5 mg/kg) or for a shorter period (3-5 days): 70-100-percent survival against not more than 30 per cent with the oral administration of the drug. It was especially evident when the animals were infected by aerosol. The results made it possible to recommend rifampicin injections in the treatment of the most severe forms of pneumonic plague.

Administration, Oral↗
PubMed1995

[Cyclosporin A and the permeability of the cytoplasmic membrane in Aspergillus niger].

Cyclosporine A was shown to impair selective permeability of cytoplasmic membranes in Aspergillus niger thus inducing leakage of low molecular components of the intracellular fond from the cells. In this respect lyposomal cyclosporine had a more pronounced action than the free form. Cyclosporine was compared with amphotericin B and the latter in the free and lyposomal forms demonstrated a higher effect on the cell membranes of Asp. niger. In combination with amphotericin B cyclosporine markedly stimulated the effect of amphotericin B on permeability of the cell membranes.

Amphotericin B↗
PubMed1994

[Comparative in vitro activity ampicillin, cefoperazone, their combinations with sulbactam, as well as that of other antibiotics against aerobic gram-negative microorganisms].

The activity of 12 antibiotics against 849 strains of gram-negative aerobes isolated in special and general hospitals of Moscow and Smolensk in 1992-1993 was assayed with the method of serial microdilutions. By the criteria of the activity (percentage of the susceptible strains by the NSSLS criteria) against the isolates the antibiotics were arranged as follows: ciprofloxacin (89.8 per cent) > imipenem (89.6 per cent) > cefoperazone + sulbactam (86.1 per cent) > amikacin (83.8 per cent) > ceftazidime (81.8 per cent) > ceftriaxone (71.1 per cent) > cefoperazone (70.9 per cent) > cefotaxime (70.9 per cent) > gentamicin (60.8 per cent) > ampicillin + sulbactam (44.7 per cent) > cefazolin (37.5 per cent) > ampicillin (23.0 per cent). The frequency of the antibiotic susceptible isolates in the special hospitals was lower at the average by 20 per cent than that in the general hospitals with respect to all the antibiotics assayed.

Ampicillin↗
PubMed1994

[Effect of cyclosporin on various metabolic processes in fungi].

Sensitivity of the representatives of Aspergillus and Piricularia to various concentrations of cyclosporine (in the submerged culture) was studied for choosing the test object for the subcellular investigation of the mechanism of the cyclosporine antifungal action. Changes in the main physiological and biochemical parameters of the fungal cells under the action of cyclosporine in concentrations of 10 to 80 micrograms per 1 ml of the medium were characterized. Low concentrations of cyclosporine (10 to 20 micrograms/ml) did not inhibit the growth of Aspergillus niger but induced stimulation of the growth processes. Only at a concentration of 80 micrograms/ml the inhibitory effect was observed. At the same time there was detected a dramatic stimulation of the culture respiration via the basic respiration chain. In the culture of Piricularia oryzae only inhibition of the culture growth even at the minimum concentration of cyclosporine (10 micrograms/ml) was recorded. Both the cyclosporine sensitive test objects i.e. A. niger and P. oryzae had an alternative cyanide resistant system of the electron transport. In the experiments with A. niger the cyclosporine effect on the synthesis of protein and RNA was revealed. The study provided data on the changes in the morphogenesis of the A. niger cells under the effect of cyclosporine.

Aspergillus niger↗
PubMed1993

[Semisynthetic penicillins: their importance in the current antibiotic therapy of infections. Penicillinase-resistant penicillins with predominantly antistaphylococcal action].

The status of isoxazolylpenicillins in the modern antibiotic therapy of staphylococcal infections is discussed from various viewpoints: the role and distribution of methicillin resistant staphylococci (MRSA), the methicillin tolerance, the clinical pharmacology and pharmacokinetics, the preferable administration routes and regimens depending on the disease severity and renal function, the prophylaxis of purulent infections, the indications to the combined therapy and possible side effects. It is indicated that one of the conditions providing the efficacy of penicillinase stable antistaphylococcal penicillins is the absolute knowledge of their properties and the joint efforts of the clinicians and bacteriologists in providing a rapid change of the drug after the detection of MRSA or methicillin tolerant staphylococci. This excludes any discredit of the drugs which are useful in the modern antistaphylococcal therapy.

Humans↗