Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This preparation (MZ-CR) was characterized by in vitro, ex vivo bioadhesion and in vivo bioavailability study. For comparison purposes a commercial extended release formulation of metronidazole (CMZ) was used as a reference. The in vitro drug-release profiles of metronidazole preparation and CMZ were similar in 0.1 M HCl and phosphate buffer pH 6.8. Moreover, metronidazole preparation and CMZ showed a similar detachment force to sheep stomach mucosa, while the bioadhesion of the metronidazole preparation was higher three times than CMZ to sheep duodenum. The results of in vivo study indicated that the absorption of metronidazole from the preparation was faster than that of CMZ. Also, MZ-CR leads to higher metronidazole Cmax and AUC relative to that of the CMZ. This increase in bioavailability might be explained by the bioadhesion of the preparation at the upper part of the small intestine that could result in an increase in the overall intestinal transit time. As a conclusion, formulating chitosan-xanthan gum mixture as a hydrophilic polymer matrix resulted in a superior pharmacokinetic parameters translated by better rate and extent of absorption of metronidazole. 相似文献
Physicochemical traits of peat-based pot substrates prepared from mixing of 20 or 40?vol.% of some different mineral fractions (sub. 1 to 7, subjected to decreasing amount of clay content of 66.1, 61.2, 49.7, 38.5, 26.0, 23.7 and 19.4%, respectively) with black peat were evaluated and then phosphorus uptake of poinsettia (Euphorbia pulcherima) simulated mechanistically as a case study pot plant. For preparation of substrate number 8, pure peat was mixed with 40?vol.% of the same mineral component as substrate number 6 (with 23.7% clay). Result revealed that adding different mineral fractions up to 40?vol.% to pure peat, water-holding capacity and total pore volume were reduced only by 11 and 15?vol.%, respectively. It was found that keeping the moisture content of peat-based substrates with 20?vol.% of mineral soils around 60%–70%, the optimum ventilation and enough free space of about 15%–25% will be provided around the root system. In addition, simulated P uptake did not change significantly with addition of 20?vol.% of different mineral components in peat-based substrates. As a result, P uptake mainly was dependent on the amount of plant available P level than different mineral fractions. 相似文献
Although trade liberalization may increase a country’s welfare, its specific effect on a country’s fishing industry has not been well studied. By decomposing the effect of international trade into four parts, i.e., scale-technique effects (ST), the indirect trade-induced composition effect (IC), the indirect effect of trade intensity through income (ITC), and the direct effect of trade intensity (DTC), this study empirically investigates the effect of trade openness on country-level fisheries production. To take into account the endogeneity of trade openness and income, we adopt the instrumental variable approach. We find that a rise in trade openness reduces fisheries catch on average. In particular, the long-run effect is large. This result implies that future production is affected by current overfishing through stock dynamics. Our decomposed elasticities indicate that the ST and ITC dominate in the trade elasticity of fisheries catch. While ST implies that overfishing would be affected by trade, ITC may either establish an “overfishing haven”, similar to a “pollution haven” in the environmental literature, or production shift of fisheries to countries with lax regulation to pass stringent regulation, which is more likely to occur in high-income countries. 相似文献
The anatomy of the auricular conchae of ruminants has been studied by intravascular injection of radiopaque latex, by dissection and by histological sectioning. Drawings were made of the vascular network. The arrangement of nerves and blood vessels in association with the ridges on the rostral (concave) surface was observed. The spaces between the ridges are relatively free of larger blood vessels, nerves, hair and sebaceous glands. This distribution is discussed in relation to the insertion of ear tags. 相似文献
Forty-one, 10-week-old newly weaned goats were randomly allocated into two groups, namely control (n=22) and treated (n=19). Kids in both groups were fed Rhodegrass hay ad libitum that contained < 0.1 mg/kg DM cobalt and 150 g/day of a commercially prepared ruminant concentrate that contained approximately 0.12 mg/kg DM cobalt. This diet provided the minimum daily requirement of cobalt as specified for sheep. The treated goats were supplemented with bi-monthly subcutaneous injections of 2000 microg of hydroxycobalamin. All goats were weighed and blood samples collected monthly for haematological, clinical biochemical and serum vitamin B12 analysis. After a 10-month experimental period the goats were slaughtered. The control animals exhibited significantly (P<0.05) lower weight gains, and had dry scruffy hair coats. In addition, there was a decline in erythrocyte counts, mean haemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Controls also exhibited significantly (P<0.05) lower levels of total serum proteins and elevated levels of serum alkaline phosphatase compared to treated goats. Fourteen (63.6%) of the control goats developed pathology consistent with reported field cases of hepatic lipidosis associated with low liver levels of cobalt. Only one (5.3%) of the treated goats developed hepatic lipidosis. Contrary to previous reports that suggested that goats are less sensitive to low levels of dietary cobalt than sheep, it is apparent that this is not the case with Omani goats. This is the first report of the induction of hepatic lipidosis in goats due to feeding low levels of cobalt in their diet. 相似文献
REASON FOR PERFORMING STUDY: While immune modulators are used routinely in equine medicine, their mechanism of action is not always known. OBJECTIVES: To determine the effect of a commercial preparation of inactivated parapoxvirus ovis (Orf virus; PPVO) on cytokine gene expression by equine peripheral blood mononuclear cells (PBMC) both in vitro and in vivo. METHODS: PBMC were prepared from 6 mixed-breed yearlings and cultured in vitro with PPVO with or without Concanavalin A (Con A) for 24 h. Effects on the expression of IFNalpha, IFNbeta IFNgamma, TNFalpha and IL-18 were analysed by real time quantitative PCR (RT-PCR). In addition, 12 yearling horses were treated with PPVO and whole blood RNA samples were prepared at regular intervals to assess effects on in vivo cytokine gene expression. Six of those yearlings were later treated with saline and served as treatment controls. Nine additional yearlings were injected intradermally with a single dose and their injection sites biopsied at 24 and 48 h for cytokine expression. RESULTS: In vitro culture of PBMC with PPVO led to a significant increase in IFNalpha and IFNbeta gene expression compared to mock-stimulated cultures. In addition, expression of IFNgamma and TNFalpha was significantly higher in PBMC stimulated with PPVO and Con A, than those stimulated with Con A alone. No changes were observed in IL-18 gene expression in vitro. Treatment of horses with a 3-dose regimen of PPVO resulted in elevation of IFNgamma gene expression, which was detected 24 h after the first dose and declined thereafter. Intradermal inoculation led to increased expression of IFNgamma along with IFNbeta, IL-15 and IL-18. CONCLUSIONS: Together these results indicate that PPVO stimulated IFNgamma production both in vitro and in vivo. Increased cytokine expression could account for its immunomodulatory activity. POTENTIAL RELEVANCE: The absence of adverse reactions and clear indications of increased expression of cytokine gene expression supports previous clinical uses for this immune modulator in those situations when increased expression of IFNgamma is warranted. 相似文献
During summer season, increase in the environmental temperature in the subtropical regions of Pakistan is negatively affecting the performance of dairy animals. The study objective was to determine the effect of ambient management (90 days) on productive and physiological performance of lactating Sahiwal cows during hot dry summer season. Fifteen lactating cows during the early lactation stage, having similar parity (3), daily milk production (6.2 l), were randomly allocated to three treatments, 5 cows each, i.e., (1) kept under roof shade only, (2) provision of fans along with roof shade, and (3) provision of roof shade, fans, and sprinklers designated as S, SF, and SFS, respectively. The fans were of 360-rpm capacity and showers were on for 40 min after every 90-min interval from 9:00 to 21:00 h. THI values were 81.1?±?0.7, 80.5?±?0.7, and 77.7?±?0.4 under S, SF, and SFS treatments, respectively. Cows were milked twice daily. Respiration rate (RR) and rectal temperature (RT) data were collected at 14:00 h on daily basis. The daily milk production was significantly higher in cows under SF (7.9?±?1 kg) followed by SFS (6.9?±?1.2 kg) and S (6.1?±?0.9 kg) treatments. The mean RT (101.0?±?0.04 °F) was significantly lower in cows under SFS than that on SF and S treatments and similarly mean RR was also lower (21.2 breaths/min) in cows under SFS followed by SF and S treatments. It is concluded that milk production and physiological performance in Sahiwal cows can be improved by fan-assisted ventilation during hot dry summer in subtropical regions. 相似文献
Bovine anaplasmosis is endemic in Pakistan where it reduces livestock productivity and leads to high mortality, especially in young animals. This study was aimed to identify the potential risk factors responsible for the occurrence and spread of anaplasmosis in cattle and buffaloes for the first time in Pakistan. A total of 900 (cattle?=?479, buffalo?=?421) blood samples were collected irrespective of age and sex from three distinct zones of Khyber Pakhtunkhhwa (KP) province of Pakistan. Polymerase chain reaction (PCR) technique was used for the molecular detection of anaplasmosis. Data collected on a piloted questionnaire including 11 predicting variables which were analyzed using R-statistical software, and association between the dependent and independent variables was assessed using univariable analysis. Automated and manual approaches were exercised, producing comparable models. Key risk factors identified in all the approaches included species of the animal, breed of animal, sex of animal, tick infestation status, previous tick history, tick control status, and acaricides used (odds ratio?>?1). The 611 bp DNA fragment specific for 16S rRNA gene of Anaplasma spp. was produced from 165 samples. The samples were confirmed for anaplasmosis through sequencing and BLAST queries. The findings of the current study conclude that by enhancing the protective measures to control the identified risk factors can reduce the spread of anaplasmosis in Pakistan.