Increase in tetracycline activity by using surface-active substances]

The antimicrobial effect of cationic and anionic surface-active substances, i.e. catamine AB and sulphonol NP-3 respectively was studied in vitro with respect to gramnegative bacteria. In non-bactericidal concentrations catamine AB significantly increased the efficacy of tetracyclines, while the anionic compound had no such effect. The increase in the tetracycline activity was due to the antibiotic increased absorption (14C-oxytetracycline as an example) on the treatment of gramnegative bacteria with catamine AB and staphylococci with catamine AB and sulphonol NP-3, which was mainly associated with impairement of the cell membrane permeability by the surface-active substances.     

Results of using morphocycline for the treatment of fresh, uncomplicated gonorrhea in men]

A total of 30 males suffering from fresh non-complicated gonorrhea were treated with morphocycline (N-morpholinmethyltetracycline). The diagnosis in all cases was confirmed by bacterioscopic and cultural tests. The drug was administered intravenously in a dose of 0.15 mg 2 times at an interval of 12 hours. Stable recovery was observed in 17 patients. Resistance to the treatment was found in 4 patients and relapses of the disease within 1 to 9 days after the treatment discontinuation were registered in 9 patients. It was concluded that morphocycline in the usual doses was not sufficiently effective.     

Comparative study of the physicochemical properties of the surface of Escherichia, their sensitivity to ampicillin and tetracycline and their capacity to absorb tetracycline]

Development of resistance to ampicillin and tetracycline in Escherichia resulted in an increase in the electrokinetic potential and a decrease in the level of hydration and isoelectric values of pH. The changes in the hydration level mainly depended on the accompanying dissociation. Studies on 3H-tetracycline binding revealed a low accumulation capacity of the resistant mutants. The rate of 3H-tetracycline binding did not depend on the changes in the physico-chemical parameters of the cell surface due to resistance and dissociation.     

Properties and stability of tetracycline hydrochloride tablets

Three forms of tetracycline hydrochloride tablets were studied, i.e. the uncoated tablets, sugar-coated tablets and the tablets with gastric-soluble film coating. The film-coated tablets had advantages in the main quality characteristics, i.e. the contents of the tetracycline-like admixtures, the active substance and solubility rate. The possibility of the tablet stability investigation by the method of "accelerated aging" was shown.     

Experimental study of the embryotropic action of tetracycline]

The general toxic and embryotropic effect of tetracycline was studied on unbred pregnant albino rats. The antibiotic was used in concentrations of 1 and 0.1 mg/m3, the maximum permissible concentration (MPC). The animals were exposed to tetracycline inhalation for 20 days of their pregnancy. On the basis of the results it was concluded that tetracycline in the concentration at the level of the MPC, i.e. 0.1 mg/m3 had under the experimental conditions a negative effect on the pregnant animals. In concentrations of 1 and 0.1 mg/m3 it had in addition an embryotropic effect. It was also shown that the pregnant animals were more sensitive to the antibiotic than the non-pregnant ones.     

Use of yohimbine hydrochloride to reverse immobilization of polar bears by ketamine hydrochloride and xylazine hydrochloride

Yohimbine hydrochloride (YH) effectively reversed the immobilizing effects of ketamine hydrochloride (KH) combined with xylazine hydrochloride (XH) in 48 wild polar bears (Ursus maritimus) handled in the summer. Single intravenous doses of YH ranging between 0.029 and 0.198 mg/kg resulted in a median time of 10 min (range: 1-123 min) to post-injection recovery from KH-XH immobilization. Convulsions and muscle twitching were observed in some bears after YH was administered and one death occurred. Median respiratory rate and heartbeat rate increased from 5 br/min to 12 br/min and 51 BPM to 79 BPM, respectively, soon after yohimbine was administered. The median time to recovery after KH-XH administration, including processing and handling time, was 113 min for bears administered yohimbine and 202 min for bears not administered YH. After YH-induced recovery, polar bears showed signs of reduced awareness and many remained recumbent for undetermined periods although they could coordinate movements, stand, and walk or run if disturbed. YH proved to be a useful antagonist to immobilization induced by KH-XH in a field situation.     

Bioavailability of tetracycline hydrochloride capsules (an in vivo study)]

Blood absorption of tetracycline hydrochloride of various dispersity levels from capsules containing tetracycline alone or in combination with additives, such as magnesium carbonate and calcium salts was studied on humans. It was found that higher dispersity levels of tetracycline hydrochloride powder in capsules was not accompanied by increased blood absorption of the antibiotic. Addition of magnesium carbonate and calcium salts to the antibiotic in the process of capsulation markedly retarded the blood absorption. Clear correlation between the antibiotic dissolution rate in vitro and intensity of its blood absorption in volunteers was shown.     

Comparative study of the regulation of catalytic activity of soluble and membrane forms of enzymes in reverse micellar systems. Gamma-glutamyltransferase and aminopeptidase]

The regulations of functioning of water soluble and membrane forms of enzymes in the systems of reversed micelles of surfactants in organic solvents are compared. By an examples of gamma-glutamyltransferase (in AOT reversed micelles in octane) and amino-peptidase (in Brij 96 reversed micelles in cyclohexane) the principal difference in the catalytic activity regulation of water soluble and membrane forms is demonstrated. The catalytic activity of the membrane form depends largely on the surfactant concentration at the constant hydration degree, whereas the activity of the water soluble form is constant under these conditions. The catalytic activity dependence on the surfactant concentration is regarded as a "test for the enzyme's membrane activity".     

Effect of trypsin on the activity of tetracycline, erythromycin and levomycetin]

Trypsin had an antimicrobial effect on Staph. aureus. Increasing of protein in the broth culture of the staphylococci was inhibited in the presence of 50 gamma/ml of trypsin by 42.8%. The activity of tetracycline, erythromycin and levomycetin increased, when they were used in combination with trypsin, the effect of the trypsin combinations with tetracycline or levomycetin was additive, while that of the combination with erythromycin was synergistic.     

Determining the phenolic components by using HPLC and biological activity of Centaurea triumfetti

Abstract

Centaurea species belonging to Asteraceae family are traditionally used herbs in treating many diseases in Anatolia. In the present study, I aimed to determine the biological activities and phenolic contents of the extracts of the aerial parts of Centaurea triumfetti collected from areas with extreme climatic conditions. The determination of antioxidant activity was performed using in vitro assays such as ABTS (2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl). Disc diffusion and microdilution methods were used for determine of antimicrobial activity. Besides that, the diabetes-related inhibition activities of enzymes such as alpha-glucosidase and alpha-amylase were determined using colorimetric methods. The phenolic components of the extracts were analysed by using HPLC. The biological activity of ethyl acetate extracts of the stem was found to be higher those than that of other extracts. This extract was also found to have high antimicrobial and enzyme inhibition activity. Moreover, the major component of the extract was found to be chlorogenic acid. In conclusion, these results suggest that C. triumfetti has the potential for pharmaceutical usage.     

Determination of the biological activity of antibiotics by using dry nutrient media

The possibility of using available dry nutrient media Nos. 5 to 12 in assays of antibiotic biological activity with the agar diffusions method was studied with respect to benzylpenicillin, gramicidin S, kanamycin sulfate, kanamycin B, oleandomycin, novobiocin, tetracycline and erythromycin. The dry media were used instead of the respective media prepared with meat hydrolyzate. Optimal conditions of the assays on such media were determined.