排序方式： 共有7条查询结果，搜索用时 15 毫秒
1
1.
Veterinary Research Communications - 相似文献
2.
3.
Al Katheeri NA Wasfi IA Lambert M Giuliano Albo A Nebbia C 《Veterinary journal (London, England : 1997)》2006,172(3):532-543
The metabolism of dexamethasone (DXM) in the camel was assessed by in vivo and in vitro techniques. Liver samples were collected at the abattoir from camels of either sex, and microsomes were isolated and characterized as to their protein and haemoprotein content as well as for their ability to metabolise several cytochrome P450 model substrates. The expression of different P450 enzymes was evaluated by means of immunoblotting, and the glucuronidating capacity was assessed with 1-naphthol as the substrate. The activity of 11 beta-hydroxysteroid dehydrogenase type 1 was assayed using metyrapone as a model substrate. To examine the in vitro metabolism of DXM, microsomes were incubated with the corticoid in the presence of either a NADPH-generating system or of uridindiphosphoglucuronic acid. In vivo metabolism of DXM was studied in two male camels, injected with a bolus intravenous dose of DXM (0.2 mg/kg body weight) and DXM metabolites were evaluated in urine samples collected at different times after the administration. DXM and metabolites were extracted using solid phase and liquid-liquid extraction, and analysed by liquid chromatography mass spectrometry (LC/MS) and by LC/MS/MS. Comparative results were obtained by in vitro and in vivo studies. Two phase I metabolites were detected: the major one resulted from reduction of the 3-carbonyl group in ring A and the minor metabolite from ring hydroxylation of ring A. Glucuronidation involved both phase I metabolites as well as the parent compound. 相似文献
4.
Nebbia C Dacasto M Rossetto Giaccherino A Giuliano Albo A Carletti M 《Veterinary journal (London, England : 1997)》2003,165(1):53-64
The apoprotein expression and the catalytic activities of cytochrome P450s involved in the biotransformation of xenobiotics were investigated in horse liver microsomes and compared with those of food producing (cattle, pigs, broiler chicks, and rabbits) and laboratory species (rats). Western blot analysis revealed the presence of proteins immunorelated to rat CYP 1A, CYP 2B, CYP 2E, and CYP 3A subfamilies in hepatic microsomes from horses and from any other examined species. With the exception of the N-demethylation of N-nitrosodimethylamine in broiler chicks, all the recorded interspecies differences were quantitative in nature. Equine preparations proved the most active in the biotransformation of the CYP 1A substrates ethoxy- and methoxyresorufin and the least active in the metabolism of aminopyrine and ethoxycoumarin. On a comparative basis, large differences were observed in the rate of the in vitro metabolism of model substrates between "minor" (rabbits, horses) and "major" food producing species. Taken in due consideration the limitations of the in vitro approach, results from this study reinforce the conclusion that studies on drug efficacy and residue depletion should be performed in each target species. 相似文献
5.
Gusson F Carletti M Albo AG Dacasto M Nebbia C 《Veterinary research communications》2006,30(3):271-283
To complete a studyaimed at investigating the pattern of the basal activities of liver xenobioticmetabolizing enzymes in major
and minor species intended for meat production, microsomal carboxylesterases and some conjugating enzyme activities were determined
and compared in liver preparations from horses, cattle, pigs, rabbits and broiler chicks, using the rat as a reference species.
Horses and broiler chicks exhibited a lower microsomal carboxylesterase activity towards indophenyl or p-nitrophenyl acetate than that measured in cattle or pig subfractions. Among food-producing species, the rate of glucuronidation
of either 1-naphthol or p-nitrophenol was in the order pigs ∼rabbits > horses >> cattle > broiler chicks. The widest variations were observed in the
acetylation capacity towards p-aminobenzoic acid or isoniazid, which in rabbits was 3-fold to 11-fold greater than that displayed by any other examined
species; low but measurable activities were found in equine and bovine cytosols. The activity of cytosolic glutathione S-transferase
(GST) accepting the general substrate 1-chloro-2,4-dinitrobenzene was significantly higher in rabbits, horses and pigs than
in rat, broiler chicks and cattle. Finally, an uneven pattern of activity towards the other tested GST substrates – 3,4-dichloronitrobenzene,
ethacrinic acid or 1,2-epoxybutane – was observed, possibly reflecting the species-related expression of different GST classes;
in this respect, the conjugative capacity displayed by horses was higher than or comparable to that found in the other food-producing
species. 相似文献
6.
The minimal inhibitory concentrations (MICs) of tylosin were determined to 67 strains of Paenibacillus larvae subsp. larvae, the causal agent of American Foulbrood (AFB) disease, from different geographical origins. MIC values obtained ranged from 0.0078 to 0.5 microg/ml. These very low values imply that no resistance to tylosin was found in any isolate of the Foulbrood pathogen. The measurement of diseased larvae with AFB-clinical symptoms in three different field studies demonstrated that tylosin treatment could be effective in vivo. No negative effects in colonies were noted at any dosage rates or forms of application. These studies demonstrate that tylosin, as tartrate, can be used to treat AFB in honeybee colonies. 相似文献
7.
American Foulbrood (AFB) of honeybees (Apis mellifera L.), caused by the Gram-positive bacterium Paenibacillus larvae is one of the most serious diseases affecting the larval and pupal stages of honeybees (A. mellifera L.). The aim of the present work was to asses the response of 23 strains of P. larvae from diverse geographical origins to tilmicosin, a macrolide antibiotic developed for exclusive use in veterinary medicine, by means of the minimal inhibitory concentration (MIC) and the agar diffusion test (ADT). All the strains tested were highly susceptible to tilmicosin with MIC values ranging between 0.0625 and 0.5 microg ml(-1), and with MIC(50) and MIC(90) values of 0.250 microg ml(-1). The ADT tests results for 23 P. larvae strains tested showed that all were susceptible to tilmicosin with inhibition zones around 15 microg tilmicosin disks ranging between 21 and 50mm in diameter. Oral acute toxicity of tilmicosin was evaluated and the LD(50) values obtained demonstrated that it was virtually non-toxic for adult bees and also resulted non-toxic for larvae when compared with the normal brood mortality. Dosage of 1000 mg a.i. of tilmicosin applied in a 55 g candy resulted in a total suppression of AFB clinical signs in honeybee colonies 60 days after initial treatment. To our knowledge, this is the first report of the effectiveness of tilmicosin against P. larvae both in vitro and in vivo. 相似文献
1