ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Bartlet, A.L., Harvey, S.&Klandorf, H. Contrasting effects of nitrofurans on plasma corticosterone in chickens following administration as a bolus or diet additive.J. vet. Pharmacol. Tlierap.13, 261–269.Administration of furazolidone as a bolus dose (8–500 mg/kg), produced a decrease in plasma corticosterone in chickens. In contrast, addition of furazolidone or furaltadone to the diet (0.04% or above, 10 days), increased plasma corticosterone. Pre‐treatment with a 200‐mg/kg bolus of furazolidone or furaltadone did not affect pentobarbitone anaesthesia time in the birds. In chickens pre‐treated with a nitrofuran in the diet, however, pentobarbitone anaesthesia time was significantly less than that in controls. Furaltadone in the diet, produced significant increases in the amount of cytochrome P‐450 and the activity of aniline hydroxylase in the liver microsomes. It is suggested that nitrofurans given in the diet stimulated corticosterone biosynthesis in the adrenal glands and induced mixed‐function oxidase activity in the liver. Nitrofurans given as a bolus did not produce these effects. Furazolidone (200 mg/kg) produced severe anorexia, which lasted 2 days in T‐line birds. The anorexia seemed to be associated with tissue damage in the birds rather than the ensuing adrenal cortical insufficiency.A. L. Bartlet, Department of Preclinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Edinburgh, Edinbu

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Brown, S.A., Zaya, M.J., Dieringer, T.M., Hunter, R.P., Nappier, J.L., Hoffman, G.A., Hornish, R.E.&Yein, F.S. Tissue concentrations of clindamycin after multiple oral doses in normal cats.J. vet. Pharmacol. Therap.13, 270–277.Eighteen normal cats were randomly allocated into two blocks with three treatment groups and dosed orally with clindamycin aqueous solution for 10 days at a dosage rate of 5.5 mg/kg twice daily (Group 1), 11 mg/kg twice daily (Group 2), or 22 mg/kg once daily (Group 3). At the end of dosing, all cats were killed and tissues were taken for clindamycin concentration analysis. Clindamycin was extracted from tissues using solid‐phase extraction columns followed by microbiological assay of clindamycin using a cylinder plate assay usingM. luteus.Recovery from each tissue was determined by inoculating known concentrations of clindamycin into drug‐naive tissues and comparing the observed concentration from the expected concentration. Confirmation that the bioassay detected clindamycin and notN‐desmethylclindamycin, its active metabolite, was done using gas‐chromatography‐mass‐spectrometry. Concentrations were highest in the lung, with tissue: serum ratios greater than 3 in all groups. Concentrations were higher in Group 3 than Group 1(P<0.05). Only liver concentrations in Group 3 werestatisticallyhigher than in Group 2, although all tissues except bone marrow and CSF had numerically higher concentrations in Group 3 than Group 2. The tissuerserum ratio was<1 in all tissues studied except bone, cerebrospinal fluid, brain, and skeletal muscle.Dr Scott Anthony Brown, Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Texas A

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Dye, J.A., McKiernan, B.C., Neff‐Davis, C.A.&Koritz, G.D. Chronopharmacokinetics of theophylline in the cat.J. vet. Pharmacol. Therap.13, 278–286.Studies of theophylline pharmacokinetics in humans have shown that a higher peak concentration and area under the curve(AUC), with a shorter time to peak (tp) occur after a morning dose than after an evening dose. The purpose of this study was to determine whether theophylline pharmacokinetics in the cat were also influenced by the administration time of day. Theophylline was administered to six cats in a three‐way cross‐over study as a single dose of intravenous aminophylline and oral sustained‐release theophylline (Slo‐bid Gyrocapsr̀ and Theo‐Durr̀ Tablets), between 08.00–09.00 h (Phase I) and 20.00–21.00 h (Phase II). Subjects were maintained on a 12‐h light (08.00–20.00 h):12‐h dark cycle. Similar to the human studies, the tpwas shorter following the morning dose. Conversely, however, the peak plasma theophylline concentrations achieved in these cats following intravenous aminophylline and oral Slo‐bidr̀ were significantly higher following the evening dose. TheAUCobtained for Theo‐Durr̀ was also significantly greater following the evening dose. No single pharmacokinetic parameter could account for the higher plasma concentrations achieved following the evening dose.J. A. Dye, Department of Veterinary Clinical Medicine, University of

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Caligiuri, R., Kollias, G.V., Jacobson, E., McNab, B., Clark, C.H.&Wilson, R.C. The effects of ambient temperature on amikacin pharmacokinetics in gopher tortoises.J. vet. Pharmacol. Therap.13, 287–291.The pharmacokinetics of amikacin were compared in two groups of tortoises, one held at 20d̀C and the other at 30d̀C. The mean (± SD) residence time for amikacin in the 30d̀C tortoises was 22.67±0.50 h; significantly (P0.05) in the steady‐state volume of distribution (Vd(ss)) between the tortoises held at 30d̀C (0.241±0.520 l/kg) and those held at 20d̀C (0.221±0.019 l/kg). The clearance rate was faster (P<0.05) in the warmer tortoises (10.65±2.42 ml/min/kg at 30d̀C compared to 5.27±0.152 ml/min/kg at 20d̀C). These data indicate that while the volume of distribution was approximately the same, amikacin remained in the colder tortoises longer because of its slower elimination. The oxygen consumption and metabolism were measured and found to be lower in the colder tortoises, almost by the same 2:1 ratio as clearance time(Cl), mean residence time(MRT), and area under the curve(AUC).The data derived from this limited study indicated that an appropriate therapeutic dosage regimen for amikacin in gopher tortoises at 30d̀C is 5 mg/kg given i.m. every 48 h.Dr Randy Caligiuri, University of Florida, College of Veterinary Medicine, Box J‐6 JHMHC, Gaine

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

O'Brien, M.A.&Duffus, W.P.H. The effects of dexamethasone, betamethasone, flunixin and phenylbutazone on bovine natural‐killer‐cell cytotoxicity.J. vet. Pharmacol. Therap, 13, 292–297.A series ofin‐vitroexperiments was performed utilizing the ability of bovine peripheral‐blood mononuclear cells (PBMC) to induce lysis of Madin‐Darby bovine kidney (MDBK) cells infected with bovine herpesvirus 1 (BHV1), in an antibody‐independent natural‐killer(NK)‐cell cytotoxic assay. The effects of dexamethasone (dexamethasone sodium phosphate), betamethasone (betamethasone sodium phosphate), flunixin (flunixin meglumine) and phenylbutazone on this NK cytolysis were studied using concentrations of the drugs ranging from well below to well above those normally attained in plasma at recommended therapeutic doses. All four drugs inhibited NK activity. For each agent a minimum inhibitory concentration (MIC50) required to inhibit NK activity by approximately 50% was calculated. For dexamethasone, betamethasone and flunixin theMIC50was lower after a 24‐h pre‐incubation of PBMC with each drug, although a marked inhibition was seen when the drug was only present during the 5‐h NK assay itself. In contrast theMIC50for phenylbutazone rose after a 24‐h pre‐incubation with PBMC.Dr W. P. H. Duffus, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Oukessou, M., Hossaini, J., Zine‐Filali, R.&Toutain, P.L. Comparative benzylpenicillin pharmacokinetics in the dromedaryCamelus dromedariusand in sheep.J. vet. Pharmacol. Therap.13, 298–303.Benzylpenicillin pharmacokinetics were compared in the dromedaryCamelus dromedarius (n=5) and in sheep (n=5) after administration of a single intravenous injection of benzylpenicillin. The data were described by an open three‐compartment model with elimination from the central compartment. Body clearance (Clb) was 4.87±0.63 ml/min/kg in the dromedary and 9.17±1.39 ml/min/kg in sheep, the steady‐state volumes of distribution (Vss) were 0.151±0.023 l/kg and 0.165±0.038 l/kg and the mean residence times(MRT)27.34±1.38 min and 14.95±4.16 min in the dromedary and in sheep, respectively. It was concluded that benzylpenicillin elimination occurs more slowly in the dromedary dian in sheep and that use of the same dosage regimen for the two ruminant species may lead to significant differences in plasma concentrations and therapeutic efficacy.P. L. Toutain, INRA Station de Pharmacologie‐Toxicologie, 180 chemin de Tournefeuille, T

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Baert, L., Herman, J.&Remon, J.P. Influence of feeding on the bioavailability of ronidazole prolonged‐release formulations in pigeons.J. vet. Pharmacol Therap.13, 304–308.The influence of feeding on the bioavailability of ronidazole (5 mg per animal) formulated as a hydrophilic‐matrix tablet or as lipophilic pellets, was evaluated in pigeons. Administered to fed pigeons, prolonged drug absorption was obtained for both formulations. In non‐fed pigeons an immediate grinding of the formulations in the gizzard resulted in rapid drug absorption. This indicates that prolonged residence of the prolonged‐release formulations in the crop obtained in the fed condition seemed the only possible means of obtaining prolonged drug release in pigeons.J. P. Remon, Laboratory of Pharmaceutical Technology, State University of Gent, Harelbekestraat 72, B‐9000 Ge

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00781.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Löscher, W., Faßbender, C.P., Weissing, M.&Kietzmann, M. Drug plasma levels following administration of trimethoprim and sulphonamide combinations to broilers.J. vet. Pharmacol. Therap.13, 309–319.Trimethoprim (TMP) was administered in combination with either sulphadiazine or sulphadimidine to broilers, and plasma concentrations were determined simultaneously by newly developed thin‐layer and/or high‐performance liquidchromatographic procedures, which also allowed quantification of the N4‐acetyl metabolites of the sulphonamides. After i.v. injection of TMP (20 mg/kg body wt) and sulphadiazine (100 mg/kg body wt), both compounds were rapidly eliminated from plasma with half‐lives of 1 and 2.7 h, respectively. Apparent volumes of distribution (3.3 and 0.96 1/kg, respectively) indicated that the tissue distribution of TMP was more extensive than that of the sulphonamide. After oral administration of the same dosages, elimination appeared to be slower compared to the i.v. injection, but this was obviously related to delayed absorption. Bioavailability after oral administration was approximately 100% of sulphadiazine, but only about 60% for TMP. Oral dosing of TMP in combination with sulphadimidine yielded similar maximum plasma concentrations of both compounds to those obtained with the combination of TMP with sulphadiazine, but the plasma concentration decline of sulphadimidine appeared to be more rapid than that of sulphadiazine after oral administration. During prolonged administration of different dosages of TMP‐sulphadiazine combinations via drinking water, only low plasma concentrations were attained by the recommended dosage of the combination. Up to 10‐fold higher dosages were tolerated by the animals without side‐effects. In view of the fact that the sensitivity of bacterial strains to TMP‐sulphonamide combinations differs widely, the plasma concentrations determined in the present study during prolonged drinking‐water medication with different dosages of a TMP‐sulphadiazine combination can be used to select effective doses for treatment of different poultry diseases.Prof. W. Löscher, Department of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, Bünteweg 1

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1990.tb00782.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY