Antibiotiki i meditsinskaia biotekhnologiia = Antibiotics and medical biotechnology最新文献

A culture of Streptomyces sp. producing a substance with antibacterial and antitumor activity was isolated from a soil sample collected in the Gorno-Altai Autonomous Province. By its UV, NMR and mass spectra the antibiotic was identified as granaticin. Mass spectral disintegration of granaticin was studied in detail: mass spectra of electron impulse (including that of high performance), field desorption, chemical ionization of positive and negative ions. Correlation relationship between directions of fragmentation of the molecular and basic moiety ions and fragments of the antibiotic structure was derived. Specific peaks of the ions providing mass spectrometric identification of the antibiotic in various natural mixtures were detected.

Accelerated elimination of sulfalen was observed in patients with chronic pyelonephritis, unimpaired glomerular filtration and lowered tubular reabsorption. This was due to lowered sulfalen reabsorption in the kidney tubules. Sulfadimethoxine pharmacokinetics in such patients was not significantly changed.

It is known that substances similar in their chemical structure and biological action to A-factor, a regulator of Streptomyces griseus differentiation are widely observed in streptomycetes. The present paper is concerned with studies on capacity for producing A-factor-like regulators in 13 strains belonging to 11 species of genus Micromonospora. It was shown that 7 strains had an A-factor-deficient test mutant effect analogous to the effect of A-factor. Relation of A-factor-like substance production to biosynthesis of sisomicin and sporogenesis was investigated in M. fusca var. sisomicini, strain RIA 1572. A-Factor-like substances were isolated from submersion culture of strain 1572 on the 6th-8th day of the culture growth. By the time it corresponded to the highest number of the spores in the medium. The highest levels of sisomicin were detected on the 3rd day of the fermentation process. After that period its concentration markedly lowered. Exogenic addition of A-factor had no effect on sisomicin biosynthesis but resulted in increased numbers of the spores.

Chemotherapeutic efficacy of mecillinam and dioxidine was studied on a model of Escherichia coli septicemia of albino mice caused by polyresistant variants of E. coli 675. It was shown that the presence of RI plasmid in the bacterial cells markedly lowered the mecillinam chemotherapeutic efficacy whereas the presence of R64 plasmid did not change the drug efficacy as compared to the plasmid-free controls. It was noted that the presence of RI and R222 plasmids in the pathogen cells increased the dioxidine efficacy while pKM-101 plasmid had a contrary effect. Correlation between the level of dioxidine resistance of E. coli 675 in vitro and the drug chemotherapeutic efficacy in animals was observed.

The effect of the antitumor antibiotic bruneomycin on antibody formation in response to immunization with sheep red blood cells and E. coli lipopolysaccharide was studied on mice. Marked suppression of the primary immune response following parenteral injection of the antibiotic before antigen stimulation and activation of antibody genesis due to oral administration of the drug in doses of 1 to 2 mg/kg was observed. An increase in the absolute and relative numbers of the antibody forming cells (AFC) in the spleen after the antibiotic oral administration in spite of a lowered total number of lymphocytes in it suggested that the AFC precursors (B-lymphocytes) were resistant to bruneomycin.

Kinetics of sisomicin antimicrobial effect on E. coli was studied in an in vitro dynamic model. Pharmacokinetic profiles observed in blood of humans treated with different polar dosing schedules i. e. bolus administration and continuous infusion were simulated. The first set of the experiments included simulating the profiles observed at short-term maintenance (0.25-20 min) of relatively high antibiotic levels after bolus administration (Cmax = 0.125-10 micrograms/ml). The second set included simulating the profiles observed at long-term maintenance (1-15 hours) of relatively low antibiotic levels after infusion (Cmax = 0.125-1.75 micrograms/ml). Changes in the viable count in the dynamic model were estimated microcolorimetrically with BioActivity Monitor LKB 2277-202. The use of the recently developed parameters of antimicrobial effect intensity IE and duration TE provided determination of relationship between IE or TE and logarithm of the area under the concentration-time curve (lg AUC). Its own IE (or TE) vs lg AUC curve including 4 phases corresponded to every administration schedule i. e. bolus and infusion. The 1st and 3rd phases reflected weak changes in IE or TE at significant increasing of the AUC and the 2nd and 4th phases reflected a marked increase in IE or TE at insignificant changing of the AUC.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of a new rifampicin dosage form developed at the All-Union Research Institute of Antibiotics was studied on dogs with extensive destructive tuberculosis of the lungs. Intracavernous instillation and rapid intravenous administration (RIA) of the drug in combination with 10 per cent solution of isoniazid and intramuscular administration of streptomycin were used. Intracavernous instillation of rifampicin in combination with 10 per cent solution of isoniazid was performed under the control of an x-ray unit with an image converter tube or with the developed administration procedure through an indwelling catheter. Intracavernous administration of the drugs was alternated with their RIA: either one-stage administration of the antibiotic in daily half doses to each cavern followed by RIA every second day or RIA of a daily half dose in the morning followed by intracavernous instillation of the second half dose to one cavern in 5-6 hours and the second half dose to the other cavern on the next day. Intracavernous instillation of rifampicin in combination with isoniazid together with their RIA in treatment of extensive destructive tuberculosis of the lungs provided 100 per cent elimination of tubercle bacilli in the internal organs of all the dogs and closing of the caverns with cicatrization in 70 per cent of the dogs and formation of microcavities in 30 per cent of the dogs within 30 days.

The process efficiency parameter used in estimation of thermal sterilization of nutrient media known as a sterilization criterion is replaced by a new one. A methodical approach to and the results of experimental determination of corrections for the sterilization criterion pattern connected with the operation factors are presented. The following parameters for measuring the criterion were elucidated: contamination of nutrient media, retention time and kinetic characteristics of test-microbe death. Sterilization conditions were calculated with the routine procedure and the new method. Comparison of the results showed that the retention time calculated with the account of the corrections was much closer to the experimental values for the time of the test-microbe death.

An affinity sorbent was synthesized on the basis of aminoethyl cellulose and dipeptide of the D-Ala-D-Ala-OH fragment of growing peptidoglycan of the bacterial cell wall. It was shown that the sorbent had highly selective affinity to antibiotics of the vancomycin group and their biologically active derivatives and provided their biospecific chromatography.