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A rapid, accurate, simple, and reproducible high performance liquid chromatographic (HPLC) method for the determination of oxytetracycline hydrochloride (OTC) in porcine plasma has been developed and validated. The drug and the standard were eluted from 5 um Omni Spher (Varian) C18 column (250 mm x 4.6 mm I.D.) at room temperature. The mobile phase was composed of ACN-MeOH-(HCOO)₂ (17.5:17.5:65 v/v/v) (pH adjusted to 2). A flow rate was 1.4 mL/min. The effluent was monitored using a UV-VIS detector set at 360 nm. The retention time of OTC was about 3 min. The suggested technique is characterised by superior performance parameters: linearity R² = 0.9999, recovery = 92.50%, repeatability RSD ≤ 1.39%. These results demonstrate the validity of the HPLC method for the analysis of OTC HCL.
A combination of colistin with tylosin, antibiotics differing profoundly by their chemical structure but of a complementary antibacterial activity was examined. In the in vitro experiments sensitivity to antibiotics of 102 E. coli isolates and 68 Salmonella spp. isolates was performed. Among E. coli isolates most isolates were resistant to ampicillin (87.2%), apramycin (73.6%) oxytetracycline (71.2%), sulfometoxazole (75.3%) and amoxycillin (43.1%). Among Salmonella spp. the highest number of isolates was resistant to Oxytetracycline (11.7%). It was found that the growth of E. coli and Salmonella isolates was more effectively inhibited by a combination of colistin with tylosin than by colistin alone. This situation is exemplified by a decrease of MIC value of E. coli for colistin + tylosin (range 0.05-0.2 µg/ml) in comparison to the value of MIC for colistin (0.08-0.2 µg/ml). In experimental chicken colibacteriosis both prophylactic and therapeutic use of the combination of colistin with tylosin completely eliminated mortality and lowered morbidity.
В поисках эффективных химиотерапевтиков исследовали чувствительность (антибиограммы) и определили величину MIC для 112 штаммов Salmonella sp. животного происхождения относительио производной налидиксиновой кислоты — флюмехина и 9 других химиотерапевтиков. На 112 штаммов Salmonella sp., происходящих от домашней птицы, свиней, телят и овец а также пушных зверей отметили только 3 штамма (2,7%), устойчивых к флюмехину, и 5 штаммов слабо чувствительных к нему (4,5%). В очередности наименьшее число устойчивых и слабочувствительных штаммов отметили: для гентамицина — 1 устойчивый (0,9%) и 22 слабочувствительных (19,6%), для апрамицина — 4 устойчивых (3,5%) и 6 слабочувствительных (5,3%) и 12 слабочувствительных (10,7%). Процент штаммов, устойчивых к остальным химиотерапевтикам, составлял: 60,7% штаммов к сульфаметоксазолу, 19,6% штаммов к интрофурантиону и стрептомицину, 16,9% штаммов к окситетрациклину и 16,0% штаммов к комбинации сульфаметазна, сульфадиметоксина и ТМР. Для 94,5% исследуемых штаммов Salmonella sp. отметили величину MIC (0,5—2 мг/мл) для флюмехина, значительно превышающую терапевтические концентрации, достигаемые животными после лечебных доз. В экспериментальных инфекциях мышей штаммов S. typhimurium отметили, что: флюменин похоже как ампициллин обеспечивает 100% продекции перед смертельным и сходом мышей.
Tiamulin, a semi-synthetic antibiotic agent, is exclusively used in veterinary medicine and is rapidly distributed in the body and intensively metabolized in the liver. The aim of the study was to estimate the residue levels of tiamulin metabolite in pigs. tissues after oral and intramuscular administration. The experiment was carried out on 38 pbz breed weaners, divided into two groups. One of the groups was administered Tiamowet 45% granulate orally at a dose of 24 mg/kg b.w./day, and the other was administered Tiamowet 200 intramuscularly at a dose of 15 mg/kg b.w./day. Both drugs were taken for 5 days. The weaners from both groups were slaughtered on days 3, 4, 6, 8, 10, 12 and 15 following the end of drug administration. Samples of tested tissues from the livers and muscles were isolated in order to measure the residue marker level. 8-α-hydroxymutilin residues were estimated according to the GC method by Marcus and Sherma in their own modification. A validation method procedure was also carried out. The GC experiment showed that 8-a-hydroxymutilin concentration in the tested muscles attains a lower level than that of MRL i.e. 100 µg/kg on day 10 following intramuscular Tiamowet 200 preparation administration and on day 12 following oral Tiamowet 45% granulate administration.
The aim of the study was to examine the influence of prebiotics (mannan oligosachacharides and b-glukanes) on alternations in peripheral blood leukocytes and interleukin 1(IL1) activity in calves. Calves in group I received feed supplemented by prebiotics. The second group of calves (group II) was the control group and received the same feed, but without prebiotics. The leukocyte subpopulations were determined by flow cytometry and the following parameters were assayed: the total number of leukocytes (WBC), general percentage of lymphocytes (LYM) and their subsets CD2+ (T lymphocytes), CD4+ (T helper lymphocytes), CD8+ (T suppressor/ cytotoxic lymphocytes) and WC4+ (B lymphocytes) as well as neutrophils (PMNL) and mid-size leukocyte per cent (MID), i.e. total value of monocytes, eosinophils and basophils. Additionally, the interleukin 1 activity in serum of the calves was estimated during the study. The obtained results indicated that the percentage of some subsets of T lymphocytes, such as CD 2+ and CD 8+, and also WC4+, significantly increased in the peripheral blood of the calves. A similar effect was observed for interleukin 1 (IL1) activity in the serum of the studied calves. The remaining leukocyte parameters did not change significantly.
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