Antibiotiki最新文献

beta-Lastamase with the molecular weight of 32500 was isolated from the cells of clinical strain 6803 of Enterobacter aerogenes and purified. By the substrate profile determined microiodometrically beta-lactamase was classified as belonging to the cephalosporinase type. The activity of the electrophoretically homogenous enzyme was equal to 430 microM a minute per mg protein with respect to benzylpenicillin. The Km for benzylpenicillin, dicloxacillin, cephaloridin and cephalothin was 6.5410(-5), 3 X 10(-4), 2.1 X 10(-5) and 5.7 X 10(-5) M, respectively. The isoelectric point of the enzyme equal to 5.45 was estimated with the method of preparative isoelectrofocusing. The presence of the serine residue or residues was shown with the use of selective reagents applied to the functionally important groups. With the method of circular dichroism the ratio of alpha- and beta-structures in the enzyme molecule was determined, the slow hydrolysis of cephazolin was demonstrated and the values of Km and Kcat for this process were estimated.

The intestinal form of salmonellosis caused by S. typhimurium and the host immunity were studied in 108 infants. 60 infants were treated with ampicillin and the other 48 infants with tobramycin. The recovery period in patients treated with tobramycin was 8 days less as compared to the patients treated with ampicillin After discontinuation of the tobramycin use the pathogen was not detected in the repeated platings. Bactericidal function of neutrophils in these patients returned to normal within 15 days after the beginning of the treatment. Tobramycin was shown to be a highly active antibiotic in the treatment of salmonellosis of infants. No side effects were observed.

Glycerol-yeast medium No. 3 may be used as a seed medium in screening of antibiotic-producing strains among Acetobacter, Gluconobacter, Chromobacterium, Agrobacterium, and other genera. The medium is transparent. It provides visual instrumental control of the growth rate of the seed material and estimation of biomass augmentation. The period of the exponential phase growth of the strains tested on medium No. 3 was 2-8 hours. When no growth on medium No. 3 is observed media Nos. 1 and 2 can be used as alternative seed media.

In connection with the new requirements to the content of antibiotics in discs and a new procedure for the disc labeling stability of antibiotics in discs was studied with the methods of storage under natural conditions and under conditions of accelerated ageing. It was shown that the method of accelerated ageing was not applicable to testing antibiotic stability in discs, since with the use of this method a significant decrease in the antibiotic activity was observed which did not correspond to the real decrease in activity determined with the method of storage under natural conditions. The expiry date of the discs with benzylpenicillin or semisynthetic penicillins was determined to be equal to 1.5 years when stored at 10 degrees C. The expiry date of the discs with thermostable antibiotics was determined to be equal to 3 years when stored at 10 degrees C. Though certain inactivation of the antibiotics was observed, their content in the discs remained within the required limits, i.e. 75-135 per cent of the activity indicated on the label.

Leukocyte interferon of various species origin (human, swine, mice) protected mice from the lethal dose of staphylococcal toxin. Endogenic mouse interferon and exogenic serum mouse interferon had no such effect. The suspension of waste leukocytes had also a protective activity. The results of the study evidence the presence of antitoxic factor in the leukocytes.

The effect of the combined use of prodigiozan (0.5 mg/kg bw) prodigiozan with immunosuppressants on the development of adjuvant arthritis was studied on rats. The drugs were given during the prearthritis period from the 1st to the 16th day after injection of complete Freund's adjuvant. It was shown that the combined use of prodigiozan and cyclophosphamide (5 mg/kg) induced significant inhibition of the arthritis development and extraarticular signs of the disease. The efficacy of the combination was higher than that of cyclophosphamide alone. Azathioprine (4 mg/kg/bw) produced no immunosuppressant effect and did not influence the inhibitory effect of prodigiozan on the development of the adjuvant disease. Prednisolone (1.6 mg/kg) either did not inhibit the arthritis development. However, it eliminated the prodigiozan effect. Methyluracil did not change the effect of the immunosuppressants on the articular syndrome. Still, it increased the number of nodular affections in the animals treated with cyclophosphamide and prednisolone. The data obtained show the possibility of prodigiozan combination with certain immunosuppressants in autoimmune affections and confirm the suggestion that the inhibitory effect of this drug is mediated through macrophages.

The state of macrophage surface structures is closely connected with the function 1 capacity of these cells. Peritoneal macrophages from mice subjected to strong 10-day immunosuppression with azathioprine (60 mg/kg), prednisolone (50 mg/kg) or their combination (25 and 30 mg/kg, respectively) were investigated with scanning electron microscopy. Azathioprine and especially its combination with prednisolone induced pronounced degenerative affections in the macrophages and lymphocytes, smoothing of their surfaces, predominance of large spread macrophages, and impairment of the intracellular cooperation. The macrophage alteration under the action of prednisolone was less pronounced. Prodigiozan, a bacterial polysaccharide (0.5 mg/kg) administered on the 4th and 9th days of the immunosuppression increased the macrophage resistance mainly to the damaging effect of prednisolone and was low effective after administration of azathioprine. The effect of lysozyme injected intramuscularly in a dose of 0.5 mg/kg daily within a period of the 3rd to the 10th days of the use of the immunosuppressants was evident from activation of the surface structures of the small macrophages and lymphocytes and reduction of cell alterations independent of the type of the immunosuppressants used. This indicates the necessity of a differential approach to the use of the macrophage activators for correcting the decreased infection resistance after medicamentous immunosuppression.

The levels of kanamycin in the bile and liver tissue were studied on 10 healthy dogs and 10 dogs with experimental acute abacterial cholecystocholangiohepatitis. It was shown that bile excretion of kanamycin in the dogs increased 6-7 times with development of acute inflammation in the biliary system.

Interaction of rifampicin with isolated subcellular fractions of the rat liver (binding and dissociation of the complexes) and intracellular distribution of the antibiotic were studied in the presence of the main organoids taken in the ratio close to the natural volume ratio of the hepatocyte cell components. The nuclei and mitochondria were most active during drug binding. The microsomes were less important. Rifampicin formed mobile complexes with organoids and was easily released from the subcellular fractions recovering its activity on washing. The intracellular distribution was the following: 37.7 per cent of rifampicin in the active form was accumulated in cytosol and the remaining amount was reversibly bound in the fractions of the nuclei, mitochondria and microsomes. The characteristic features of the cell pharmacokinetics of rifampicin, i.e. significant concentration in cytosol, possible deposition in the subcellular structures and at the same time the capacity for recovery of the activity might define the antimicrobial potential of this antibiotic in respect to the intracellular microorganisms.

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.