Vibrational spectra, structure and antioxidant activity of gossypol imine derivatives.

The structures and tautomeric equilibria of natural polyphenol gossypol and four its imine derivatives were studied by FT-IR-, NMR-spectroscopy and quantum chemistry methods. It was shown that gossypol Schiff bases exist in solution as enamine-enamine tautomer and hydrazones as imine-imine tautomer. Infrared absorption spectra of studied compounds were simulated using the PM3 method. The fundamental vibrational frequencies were evaluated using various scale factors which yield a good agreement between observed and calculated frequencies. Free radical scavenging activity of gossypol and its imine derivatives was evaluated using DPPH method. Antioxidant activity of studied compounds was characterized. Gossypol hydrazones were shown to be more efficient, while Schiff base to be less efficient as antioxidants in comparison with gossypol itself.

[A comparative evaluation of the pharmacokinetics of different forms of benzathine benzylpenicillin]. / Sravnitel'naia otsenka farmakokinetiki razlichnykh lekarstvennykh form benzatin benzilpenitsillina.

Comparative randomized opened pharmacokinetic evaluation of benzathine benzylpenicillin in three dosage forms was performed. Benzathine benzylpenicillin was used as extencilline (2.4 million U or 1.2 million U, "Rhône-Poulenc Rorer", France) and as bicillin-5 (1.5 million U, "Synthesis" Russia). 33 patients were included in investigation (23 women and 10 men aged 16-60 years). 25 persons had verified rheumatism without blood circulation failure signs, 4--had chronic tonsillitis and 4 were healthy volunteers. Benzylpenicillin concentration was estimated by microbiology test in blood samples taken at 1, 3, 24 hours and 7, 14 and 21 days after intramuscular drug injection. After 2.4 million U extencilline injection (12 patients) its concentration, was at the inhibition level for beta-hemolytic streptococcus group A (25 ng/ml) for 3 weeks-period in 83.3 per cent of patients. After 1.2 million U extencilline injection (10 patients) or 1.5 million U bicillin-5 injection (12 patients) the above mentioned concentration was achieved on the 21st day in 30 and 0 per cent of patients respectively. Thus the treatment with benzathine benzylpenicillin at the 1.2 million U dose in the form of extencilline or bicillin-5 doesn't provide adequate antistreptococcal concentration in blood in prolonged period and is not suitable for correct rheumatism prophylaxis in adult patients.

[Characterization of antimicrobial properties of cefpirome]. / Kharakteristika antimikrobnykh svoistv tsefpiroma.

The results of a multicentre investigation of antibiotic susceptibility in 800 clinical isolates were analyzed. The levels of susceptibility to cefpirome and other antibiotics in gram-negative organisms with inducable production of chromosomal beta-lactamases (Enterobacter, Serratia, Citrobacter and others) were compared and the advantages of cefpirome over other cephalosporins were shown: 89 per cent of the susceptible strains against 58 to 78 per cent. With respect to other microorganisms the advantages of cefpirome were less pronounced.

[Mechanisms of resistance to quinolones and current level of sensitivity of clinically important microorganisms to ofloxacin]. / Mekhanizmy ustoichivosti k khinolonam i sovremennyi uroven' chuvstvitel'nosti klinicheski znachimykh mikroorganizmov k ofloksatsinu.

The data on the mechanisms of microbial resistance to fluoroquinolones are presented. Comparison of the susceptibility levels of the microorganisms isolated on the territory of Russia showed that among the gram-negative opportunistic isolates 84 per cent was susceptible to ofloxacin, 45 per cent to ampicillin/sulbactam, 70 per cent to cefotaxime, 80 per cent to ceftazidime, 85 per cent to amikacin and 62 per cent to gentamicin. Among the Salmonella, Shigella and Vibrio cholerae isolates no strains were resistant to ofloxacin. Among the Salmonella isolates from patients more than 30 per cent was resistant to ampicillin, chloramphenicol, trimethoprim/sulmethoxasole and tetracycline. Among the Salmonella isolates 65 to 90 per cent was resistant to the antibiotics. Among the V.cholerae isolates 59 per cent was resistant to trimethoprim/sulmethoxasole.

[Microturbidimetric method for determining the activity of polymyxin M]. / Mikroturbidimetricheskii metod opredeleniia aktivnosti polimiksina M.

A microturbidimetric procedure for the assay of polymyxin M activity was developed. The assay is performed in polystyrene 96-well plates usually used for immunological tests.

[Sorption of aminoglycoside antibiotics from unfiltered culture fluid]. / Sorbtsiia antibiotikov-aminoglikozidov iz nefil'trovannoi kul'tural'noi zhidkosti.

Sorption of aminoglycosides such as sisomicin, gentamicin, kanamycin and streptomycin from the non-filtrated fermentation broth by carboxylic cation exchange resins under the static conditions was studied. The optimal conditions for the sorption of the aminoglycosides and their subsequent desorption were determined (the ratio of the volumes of the sorbent and fermentation broth and the time of the sorption and desorption).

[A spectrophotometric method of analysis of fusidic acid]. / Spektrofotometricheskii metod opredeleniia fuzidievoi kisloty.

A spectrophotometric method for assay of fusidic acid is described. The method is based on reaction with a reagent consisting of acetic anhydride and concentrated sulfuric acid. Mathematical processing of the results of the main substance determination in fusidic acid preparations showed that the error did not exceed 2 per cent. Procedures for spectrophotometric assay of fusidic acid in control of the processes of its biosynthesis, isolation and purification were developed. The procedures provided control of the technological process of fusidic acid production.

[Structural and functional study of polymyxins. Isolation and properties of individual components of polymyxin M]. / Strukturno-funktsional'nye issledovaniia polimiksinov. Vydelenie i svoistva individual'nykh komponentov polimiksina M.

LPCC and HPLC revealed that polymyxin M was a mixture of five components of the polymyxin nature: PM1, PM2, PMx, PMy and PMz. The individual compounds PM1, PM2 and PMz were isolated. Their physicochemical properties and data on antimicrobial activity are presented.

[Use of agar diffusion method for separate determination of concentration of streptomycin and rifampicin in the blood in the presence of isoniazid]. / Metod diffuzii v agar dlia razdel'nogo opredeleniia kontsentratsii streptomitsina i rifampitsina pri ikh sovmestnom prisutstvii s izoniazidom v syvorotke krovi.

Conditions for determination of streptomycin and rifampicin in the blood serum on their combined use, as well as in the presence of isoniazid are described. For determination of the blood levels of streptomycin administered in combination with rifampicin it is recommended tat a variant of Bac. mycoides 537 resistant to rifampicin be used. When the rifampicin levels are determined in undiluted serum, the value obtained should be multiplied by 1.4. When a 2-fold dilution of the serum is used, the value is multiplied by 1.15. This provides an indicator maximally close to the real content of the antibiotic in the blood serum.

[Changes in microorganism sensitivity to antibiotics as affected by divalent metal ions]. / Izmenenie chuvstvitel'nosti mikroorganizmov k antibiotikam pod vliianiem ionov dvukhvalentnykh metallov.

Ca+ and Mg+ in nutrient media significantly influence the results of antibiotic sensitivity determination in microorganisms. The data of the study are indicative of a necessity for the media standardization with respect to the content of bivalent metal ions. It is recommended that agar-agar manufactured by the South Sea Factory (tafuinsky) be used for preparation of nutrient media for determination of microbial sensitivity to antibiotics and Hottinger meat pancreatic digest as the nitrogen source providing the content of 120 mg per cent of amine nitrogen in the medium.

[Increase in the sensitivity and a simplification of the method for the separate determination of antibiotic activities in combined preparations (oletetrin) by using media with a varying pH value]. / Povyshenie chuvstvitel'nosti i urposhchenie metoda razdel'nogo opredeleniia aktivnosti antibiotikov v kombinirovannykh preparatakh (oletetrin) prispol'zovanii sred s razlichnym znacheniem pH.

An agar-diffusion method for determination of oleandomycin and tetracycline low levels in solutions of the drug combination was developed. The medhod may be used for investigation of oletetrin absorption and distribution in humans and animals. It provides high accuracy in separate determination of oleandomycin and tetracycline activity in solutions of the drugs at a ratio of 1 : 2. The same test-culture, Bac. subtilis, variant L2 is used for the assay of tetracycline and oleandomycin activity. The only differences are in the values of pH and the buffer solution and the standards.

[Effect of different grades of agar-agar on the nature of the test microbe growth inhibition zones in controlling antibiotic activity by means of agar diffusion]. / Vliianie razlichnykh sortov agar-agara na kharakter zon zaderzhki rosta test-mikrobov pro kontrole aktivnosti antibiotikov metodom diffuzii v agar.

The effect of various agar grades on the size and margin character of the inhibition growth zones in assay of antibiotic activity by the agar diffusion method was studied. It was shown that not all the agar grades could be used in antibiotic activity assay. Depending on the agar type the size of the inhibition growth zones produced by the same antibiotic concentration significantly varied. The variations in the size of the inhibition growth zones depended on the agar ability to bind antibiotics and were mainly defined by the agar purity. The agars with low content of nitrogen admixtures bound the antibiotics to a low extent. The commerical grades of the agars of the South-Sea and Korsakov Plants, the experimental grade of the TINRO agar with additional purification, as well as the agars imported from Argentina and France proved to be most useful for determination of the antibiotic activity by the agar diffusion method.

[Determination of rifamycin B activity in culture liquids and in preparations with varying degrees of purity]. / K voprosu opredeleniia aktivnosti rifamitsina B v kul'tural' nykh zhidkostiakh i v preparatakh raznoi stepeni ochistki

A possibility of using the biological method of rifamycin B activity determination in the fermentation broth and dry preparations of various purity levels was studied. It was found that the biological method was useful only for determination of rifamycin B activity in preparations containing not less than 850 gamma/mg of the main product. When the activity of rifamycin B was determined in the fermentation broth and crude preparations containing less than 800 gamma/mg of the main product, the results of the biological assay were always higher as compared to those of spectrophotometrical estimation. It was accounted for the effect of other rifamycin types possessing high biological activity.

[Antigenic properties of 1-asparaginases isolated from different species and strains of bacteria]. / Antigennye svoistva 1-asparaginaz, vydelennykh iz razlichnykh vidov i shtammov bakterii

Immunological relation of L-aspariginase isolated from different strains of E. coli and Ervinia carotovera was investigated by the method of specific neutralization of the asparaginase effect on asparagin in the presence of immune antiasparaginase serum and the method of microprecipitation in agar. It was found that there was immunological relation between asparaginases of different strains of the same microbial species. At the same time common antigens were absent in asparaginases synthesized by different bacterial species.

[Microbiological study of gentamiycin]. / Mikrobiologicheskoe izuchenie gentamitsina

Gentamycin prepared at the All-Union Research Institute of Antibiotics did not differ by its antibacterial spectrum and the activity level from gentamycin samples from other countries. By its activity against clinical strains of Ps. aeruginosa gentamycin was somewhat inferior than polymyxin but much more superior than carbenicillin. An agar-diffusion method using Bac. pumilus NTCC 8241 as the test microbe was developed for determination of gentamycin activity. The gentamycin sulfate complex and the components of gentamycin had the same activity levels, antibacterial spectrum and diffusion capacity.