Detection of R factors in naturally occurring Aeromonas salmonicida strains.
(17/32)
R factors were detected in Aeromonas salmonicida strains isolated from diseased salmonid fish. One of such R(+) strains was the one isolated in the United States as early as 1959. (+info)
Species variations in the threshold molecular-weight factor for the biliary excretion of organic anions.
(18/32)
1. The excretion in the bile and urine after intravenous injection of 16 organic anions having molecular weights between 355 and 752 was studied in female rats, guinea pigs and rabbits. 2. These compounds were mostly excreted unchanged, except for three of them, which were metabolized to a slight extent (<7% of dose). 3. The rat excreted all the compounds extensively (22-90% of dose) in the bile. 4. In guinea pigs four of the compounds with mol.wt. 355-403 were excreted in the bile to the extent of 7-16% of the dose, four with mol.wt. 407-465 to the extent of 25-44% and eight compounds with mol.wt. 479-752 to the extent of 44-100%. 5. In rabbits four compounds with mol.wt. 355-465 were excreted in the bile to the extent of 1-8% of the dose, two compounds with mol.wt. 479 and 495 to the extent of 24 and 22%, and six compounds with mol.wt. 505-752 to the extent of 31-94%. 6. These results, together with those of other investigations from this laboratory, are discussed and the conclusion is reached that there is a threshold molecular weight for appreciable biliary excretion (i.e. more than 10% of dose) of anions, which varies with species: about 325+/-50 for the rat, 400+/-50 for the guinea pig and 475+/-50 for the rabbit. 7. Anions with molecular weights greater than about 500 are extensively excreted in the bile of all three species. 8. That proportion of the dose of these compounds which is not excreted in the bile is excreted in the urine, and in the three species, bile and urine are complementary excretory pathways, urinary excretion being greatest for the compounds of lowest molecular weight and tending to decrease with increasing molecular weight. 9. Some implications of this interspecies variation in the molecular-weight requirement for extensive biliary excretion are discussed. (+info)
Identification of flavanone metabolites in rat urine by combined gas-liquid chromatography and mass spectrometry.
(19/32)
1. The metabolism of flavanone in the rat was studied after oral or intraperitoneal administration of the compound. Flavone and flav-3-ene together with five other unidentified minor metabolites were excreted in the urine. 2. The formation of flavanone metabolites was not suppressed by the administration of high doses of the antibacterial compounds aureomycin and phthaloylsulphathiazole. 3. No aromatic acids that could be attributed to ring cleavage of flavanone were detected. 4. Administration of 100 or 200mg of flavanone daily per rat caused some deaths during the 7-14-day period. 5. The application of combined gas-liquid chromatography/mass spectrometry and proton nuclear-magnetic-resonance spectroscopy to the separation and identification of the flavanone metabolites is described. 6. Measurement of the two major flavanone metabolites was carried out by gas-liquid chromatography. (+info)
Rapid sulfonamide disc sensitivity test for meningococci.
(20/32)
Minimal inhibitory concentrations (MIC) of 90 strains of Neisseria meningitidis were determined by a plate dilution technique that employed twofold changes in concentrations of sulfadiazine. The geometric mean of three MIC determinations on each strain was correlated with inhibition zones produced by a 300-mug sulfathiazole disc. The linear relationship between the logarithm of the geometric mean MIC values and the zone diameters was highly significant. Strains were separated into sensitive and resistant populations by both test procedures. Quantitative criteria for interpreting the sensitivity of a strain by the disc test were established. (+info)
Potentiation of inhibitory activity of colistin on Pseudomonas aeruginosa by sulphamethoxazole and sulphamethizole.
(21/32)
Potentiation of colistin by sulphamethoxazole and sulphamethizole was demonstrated with 19 out of 20 strains of Pseudomonas aeruginosa. This enhancement was bactericidal as well as bacteriostatic. Synergy between trimethoprim and sulphamethoxazole was also demonstrated with four strains of Ps. aeruginosa, but even when the two drugs were combined high concentrations of trimethoprim were still required to produce a bactericidal effect. Combinations of sulphamethoxazole and gentamicin appeared to be synergistic when the bacteriostatic effect was measured, but the combined bactericidal effect was indifference. The bactericidal and bacteriostatic effect of combinations of carbenicillin with sulphamethoxazole was also indifference. (+info)
Sensitivity of Escherichia coli to atabrine conferred by R factor and its potential clinical significance.
(22/32)
A comparative study of the inhibitory effect of Atabrine on R(-) and R(+) strains of Escherichia coli showed that R(+) cells were killed when grown in the presence of Atabrine, whereas R(-) cells were not. It would appear, therefore, that R factor confers sensitivity to Atabrine on the host cells. The "curing" of R factor from R(+) cells by the ultraviolet light-acridine orange method rendered the "cured" cells more resistant than even the parent R(-) cells. The "cured" cells reinfected by R factor were more sensitive than the "cured" cells but less sensitive than the original R(+) cells. After growth once in Atabrine, and even after subcultures in drug-free medium, the growth of R(+) cells in the presence of Atabrine was more rapid than that of the R(-) cells. R(-) cells made resistant by growing them repeatedly in streptomycin, chloramphenicol, tetracycline, and sulfathiazole in succession also showed a higher degree of sensitivity to Atabrine than the original R(-) cells. When mixtures of R(-) and R(+) cells were grown in 120 mug/ml of Atabrine, R(+) cells were killed and the culture consisted predominantly of R(-) cells. A mixture of R(-) and R(+) cells (1:10,000) inoculated into the Atabrine-containing medium and treated 24 hr later with chloramphenicol was completely killed. (+info)
Studies on flavonoid metabolism. Metabolism of (+)-catechin in the guinea pig.
(23/32)
1. Administration of (+)-catechin to the guinea pig gives rise to a number of phenolic acids and lactones, which have been identified by chromatographic and spectrophotometric methods. The major phenolic acid metabolite is m-hydroxybenzoic acid and the major lactone metabolite is delta-(3-hydroxyphenyl)-gamma-valerolactone. 2. The phenolic acid and lactone metabolites are excreted in both free and conjugated forms, including their glucuronides and to a lesser degree their ethereal sulphates. 3. Administration of certain of the metabolites isolated has permitted certain sequential relationships of these intermediates to be established. 4. Degradation of (+)-catechin in the guinea pig is effected at least in part by the gut microflora and is suppressed by aureomycin plus phthaloyl-sulphathiazole. (+info)
The use of metronidazole in the preparation of the bowel for surgery.
(24/32)
The preliminary results of this study have shown that a combination of oral phthalylsulphathiazole and metronidazole for preparation of the bowel for surgery reduces the incidence of postoperative infection compared with phthalylsulphathiazole alone. (+info)