盐酸沙拉沙星在鸡体内的药代动力学及残留的研究

为研究盐酸沙拉沙星在蛋鸡体内组织动力学与残留，选用成年健康蛋鸡95只进行试验。按10mg/kg体重口服给药，给药后定期采样，测定血清及心，肝，肾，肌肉中盐酸沙拉沙星的含量。结果表明：盐酸沙拉沙星在血液中经时过程符合一级吸收一室模型，主要动力学参数t1/2k3.793h,tmax1.5807h,cmax0.7429μg/ml,AUC5.3790μg/ml.h。心脏，肾脏符合一级吸收三项指数方程，主要动力学参数分别为t1/2B7.765h,40.26h,t1/2a1.6027h,4.418h,tmax1.6826h,1.9855h,cmax0.5129μg/ml,0.9090μg/ml,AUC9.0265,10.894μg/ml.hμg/ml.h。肝脏，肌肉符合一级吸收二项指数方程，主要动力学参数分别为t1/2k3.1587h,4.124h,tmax1.9764h,3.5679h,cmax3.737μg/ml,0.6956μg/ml,AUC31.354μg/ml.h,5.3269μg/ml.h。盐酸沙拉星在蛋鸡体内残留为7天。     

盐酸沙拉沙星在蛋鸡体内的血液动力学的研究

为研究盐酸沙拉沙星在蛋鸡体内血液动力学 ,选用成年健康蛋鸡 6 5只进行试验。按 10mg/kg体重口服给药后 ,测定血清中盐酸沙拉沙星的含量。结果表明 :盐酸沙拉沙星在血液中经时过程符合一级吸收一室模型 ,其理论方程为Cb=1.0 36 (e-0 .173 5t-e-2 .0 57t)。Ka 为 1.6 0 2 5h-1、Cmax为 0 .74 2 9μg/mL、tmax为 1.5 80 7h。由抗生素后效应及药动学参数 ,建议临床给药口服方案为 10 .12mg/kg。     

健康仔猪口服亚硒酸钠的血液中药代动力学的研究

本实验按0.6mg/kgBW单剂量对健康仔猪口服亚硒酸钠溶液后，首次系统地研究了其在血液中药物代谢动力学。实验结果表明，血液动力学特征符合一级吸收二室开放模型，其理论方程为：C＝0.0820e^-0.0421t 0.1050e^-0.0014t-0.1870e^-2.2541t。主要动力学参数为：吸收半衰期（t1/2Ka)为0.3075h，达峰时间（tmax)为2.1517h；消除半衰期（t1/2β）为510.2706h，曲线下面积（AUC）为75.1460mg/L.h；表观分布容积（Vd)为5.5742L/kg。根据单剂量药动学参数，计算多剂量给药参数，为临床治疗制订给药方案，先导剂量（D^*)为1.2262mg/kg BW，维持剂量（D0）为0.6mg/kgBW，给药间隔（τ）为480h，平均稳态血药浓度（c)为0.1566μg/ml。     

司帕沙星在雏鸡体内药代动力学及残留的研究

选用30日龄健康海兰鸡65只,按5mg／kg体重口服给予司帕沙星,定期采样,以高效液相色谱法测定血浆、肝、肾、心、肺和肌肉中司帕沙星的含量,研究司帕沙星在鸡体内的药动学与残留。结果表明:司帕沙星在血液中经时过程符合一级吸收二室开放模型,其主要动力学参数如下:t1／2α0.9585h,t1／2β11.7447h,tmax0,6514 h,Cmax0.5271 μg／ml,AUC1.7908mg／L／h。肾脏、心脏的药时数据符合一级吸收二项指数方程,其主要动力学参数分别为:t1/2Ka0.3733 h、0.1530h,t1／2k1.3007 h、2.1013h,tmax1.01420h、0.6239 h,Cmax2.1104μg／ml、1.6721 μg／ml,AUC6.51764 mg／L／h、6.2286mg／L／h。司帕沙星在肝脏、肺脏、肌肉中的经时过程符合一级吸收三项指数方程,主要动力学参数分别为t1/2α0.3672 h、0.6156 h、1.5835 h,t1/2β3.9998 h、15.0271 h、12.0103h,tmax0.7458 h、0.7322 h、1.3726 h,Cmax4.4709μg／ml、2.5267μg／ml、0.9760μg／ml,AUC20.893 mg／L／h,27.242 mg／L／h、9.7943mg/L/h。建议司帕沙星在鸡体内的休药期为7d。     

单诺沙星(Danofloxacin)在雏鸡体内的组织动力学及残留

以高效液相色谱法为定量手段,研究了单诺沙星(danofloxacin)在雏鸡体内的组织动力学特征,并采用回归分析法研究了血药浓度与组织药物浓度间的相关性.60只雏鸡口服单诺沙星(5 mg/kg)后,血浆的药时数据符合一级吸收二室模型.肝脏、肾脏、心脏、肺脏的药时数据符合一级吸收三项指数方程;心脏的药时数据符合一级吸收二项指数方程.血浆、肝脏、肾脏、心脏、肺脏及肌肉的主要动力学参数是:t1/2ka分别为0.242 8、0.352 4、0.354 1、0.264 3、0.337 7、0.253 6 h、ti/2α分别为0.891 7、1.121 2、0.718 9、1.614 2、0.443 7 h(缺肌肉的ti/2α),t1/2β分别为8.793 6、3.602 5、4.457 0、10.294 0、4.328 3、5.957 8 h,Tp分别为0.937 7、1.066 5、0.936 2、0.999 3、0.996 2、1.438 1 h,Cmax分别为0.548 7、2.841 9、2.429 5、0.266 8、1.704 2、0.272 6 mg/L,AUC分别为3.052 3、13.586 0、10.418 0、2.152 1、9.688 8、2.715 7 mg/(L@h),Tcp分别为12.613 0、18.073 0、18.879 0、8.055 7、19.693 0、13.860 0 h.研究结果表明,组织中的药物浓度以肝脏、肾脏最高,其次是肺脏,均显著高于血浆中的药物浓度,心脏、肌肉中的浓度最低,血浆的有效浓度维持时间均显著长于各组织.     

盐酸沙拉沙星在兔体内的药物动力学及生物利用度研究

选用24只健康哈白兔，分3组，每组8只，进行药物动力学研究。静注、内服和肌注剂量均为10mg/kg。以反相高效液相色谱法，测定了血清中的药物浓度，所得药时数据用MCPKP程序处理，得出了药动学参数，拟合方程及肌注和内服的生物利用度。结果表明，哈白兔静注盐酸沙拉沙星后的药时数据符合无吸收因素二室模型，主要药动学参数如下Vd4.67±0.75L/kg，t1/2α0.54±0.12h，t1/2β4.43±0.186h，AUC13.86±2.63μg/ml*h，ClB0.75±0.16L/kg*h。兔内服盐酸沙拉沙星后，药时数据符合一级吸收一室开放式模型，主要药动学参数如下t1／2ka0.36±0.08h，t1/2Kel5.94±1.09h，tmax1.53±0.15h，cmax0.41±0.09μg/ml,AUC4.19±0.86μg/ml*h，生物利用度为30.22%。兔肌注盐酸沙拉沙星后，药时数据符合一级吸收二室开放式模型，主要药动学参数如下t1/2ka0.06±0.01h，t1/2α0.83±0.16h，t1/2β5.01±1.14h，AUC10.75±1.38μg/ml*h，tmax0.27±0.02h，cmax3.52±0.38μg/ml，生物利用度为77.58%。     

乳炎消在奶牛体内的药代动力学研究

给乳牛单剂量肌注0.73mg/kg乳炎消后不同时间采集血样，采用紫外分光光度法测定血药浓度。应用MCPKP药动学程序自动拟合处理血药浓度－时间数据，并求出药动学参娄。血药浓度－时间曲线符合一级吸收－一室开放模型。最佳药时方程Ci=17.8(e^-0.333t-e^-1.57t)。主要药动学参数：t1/2Ka为0.441h,t1/2K为2.082h,tmax为1.395h,Cmax为11.671μg/mL，AUC53．477mg/lh,Tcp为12.733h。根据单剂量给药参数计算出多剂量给药参数：г为12h,D^*为0.mL/kg,D（维持剂量）为0.08mL/kg。     

磺胺嘧啶在实验性肾功能损害家兔体内的药代动力学研究

分别测定了SD在6只健康家兔及6只肾损害家兔体内的代谢动力学参数。单剂量静脉快速注射SD 140mg／kg，8h内不同时间心脏采血，测定血药浓度。结果表明，SD在家兔体内的药代动力学配置符合无吸收因素二室开放模型。药-时曲线方程为：C正常=13．429e^-7.968t和 32．928e^-0.522t，C肾损=16．559e^-3.942t 26．433e^-0.322t。肾损害家兔与健康家兔相比，α下降了50．53％；8下降了38．34％；t1／2α延长了123．46％；t1／2β延长了63．15%；AUC增加了34．22％；CLB降低了22．12％。结果显示家兔肾功能损害后，SD在其体内代谢发生了显著变化。提示在肾脏损害时应相应增大SD给药间隔时间或减小给药剂量。     

单诺沙星（Danofloxacin）在雏鸡体的组织动力学及残留

以高效液相色谱法为定量手段 ,研究了单诺沙星 (danofloxacin)在雏鸡体内的组织动力学特征 ,并采用回归分析法研究了血药浓度与组织药物浓度间的相关性。6 0只雏鸡口服单诺沙星 (5 m g/ kg)后 ,血浆的药时数据符合一级吸收二室模型。肝脏、肾脏、心脏、肺脏的药时数据符合一级吸收三项指数方程 ;心脏的药时数据符合一级吸收二项指数方程。血浆、肝脏、肾脏、心脏、肺脏及肌肉的主要动力学参数是 :t1 /2 ka分别为 0 .2 42 8、0 .35 2 4、0 .35 41、0 .2 6 43、0 .3377、0 .2 5 36 h、t1 /2α分别为 0 .8917、1.12 12、0 .7189、1.6 142、0 .44 37h(缺肌肉的 t1 /2α) ,t1 /2β分别为 8.7936、3.6 0 2 5、4.45 70、10 .2 940、4.32 83、5 .95 78h,Tp分别为 0 .9377、1.0 6 6 5、0 .936 2、0 .9993、0 .996 2、1.4381h,Cmax分别为0 .5 487、 2 .8419、 2 .42 95、 0 .2 6 6 8、 1.70 42、 0 .2 72 6 m g/ L ,AUC分别为 3.0 5 2 3、 13.5 86 0、 10 .4180、 2 .15 2 1、9.6 888、2 .715 7mg/ (L· h) ,Tcp分别为 12 .6 130、18.0 730、18.8790、8.0 5 5 7、19.6 930、13.86 0 0 h。研究结果表明 ,组织中的药物浓度以肝脏、肾脏最高 ,其次是肺脏 ,均显著高于血浆中的药物浓度 ,心脏、肌肉中的浓度最低 ,血浆     

盐酸沙拉沙星在肉鸡组织中的残留

建立了肉鸡组织中盐酸沙拉少星的HPLC测定方法，并测定了肉鸡单次内服（每1kg体重10mg)和连续5d混饮（每1L饮水50mg）给药后组织中的沙拉沙星残留特征。组织样品用乙腈-氨水匀浆，离心后取上清液用正已烷-乙醚除脂，水相用磷酸酸化后作HPLC检测。色谱柱为Hypersil C18柱，此外检测波长280nm。流动相为乙腈-2%西丁基溴化铵（体积比10：90），用磷酸调pH值至2.5。肝脏、肾脏、肌肉中沙拉沙星的检测限为0.05μg/g，组织样品回收率均大于90%。鸡单次内服盐酸沙拉沙星后，24h内各组织中均可检出药物，48h后肝脏、肾脏、肌肉中药物残留量均低于0.05μg/g；混饮停药后，6h内肝脏、肾脏中可检出残留药物，12h后3种组织中残留量均低于0.05μg/g。结果表明，盐酸沙拉沙星的肉鸡组织中消除迅速，连续治疗剂量用药后组织中无药物蓄积。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein