富锌酵母的药代动力学及生物利用度研究

选用10只健康蛋鸡进行口服富锌酵母和硫酸锌的药物代谢动力学和生物利用度研究。采用原子吸收法测定血浆锌浓度,药-时数据经MCPKP程序处理,结果口服富锌酵母和硫酸锌在蛋鸡体内运转适合一室开放模型,主要药代动力学参数:富锌酵母为tmax=2.11h,Cmax=2.42μg/mL,Ka=1.06h-1,t1/2Ka=0.76h,t1/2K=2.47h,Kel=0.29h-1;硫酸锌为tmax=2.27h,Cmax=1.63μg/mL,Ka=1.19h-1,t1/2Ka=0.74h,Kel=0.31h-1,t1/2K=2.32h;口服高锌酵母的相对生物利用度F(AUC富锌酵母/AUC硫酸锌)=148%,显示蛋鸡口服富锌酵母要比硫酸锌效果好,为其1.48倍。     

喹烯酮在猪、鸡体内的药代动力学研究

猪6头,鸡10只,单剂量0 4065mg·kg-1(比活度24 6μci mg-1)静注给药,一个月后,单剂量31 15mg·kg-1(比活度5 187μci·mg-1)口服给药,进行代谢动力学研究。依据本实验建立的方法,以液体闪烁谱仪计数法进行含量测定。喹烯酮以原药的形式代谢排泄,静注给药符合二室开放模型:猪,T1/2α=0 1899h,T1/2β=4 5528h,Kel=0 8654h-1,AUC=0 00925mg·h-1·L-1;鸡,T1/2α=0 1637h,T1/2β=3 8189h,Kel=1 6834h-1,AUC=0 005046mg·h-1·L-1。口服给药符合一级吸收一室开放模型:猪,T1/2Ka=0 4678h,T1/2β=3 7445h,Tp=1 3367h,Cmax=0 000713μg·ml-1,AUC=0 00303mg·L-1·h-1;鸡,T1/2Ka=0 5142h,T1/2β=4 6637h,Tp=1 8459h,Cmax=0 000897μg·m-1,AUC=0 00773mg·L-1·h-1,说明喹烯酮口服给药后,其吸收较快,消除相对也较快,生物利用度低。     

喹烯酮在猪体内的代谢动力学研究

猪5只,单剂量30 mg/kg口服给药,进行代谢动力学研究.依据本实验建立的HPLC方法进行血液中药物含量测定.口服给药符合一级吸收一室开放模型:T1/2Ka=2.87 h,T1/2K=5.05 h,Tp=6.53 h,Cmax=0.28μg/mL,AUC=3.78 mg·L-1·h,说明喹烯酮口服给药后,其吸收较慢,消除较快,生物利用度较低.     

哒螨灵注射剂和口服剂药物动力学试验

本文对哒螨灵注射剂和口服剂应用白家兔进行了药物动力学试验,分别测定出哒螨灵注射剂和口服剂在白家兔体内吸收速率常数(Ka),消除速率常数(K),药物吸收一半时间(T1/2Ka),生物半衰期(T1/2),药峰时间(Tp),曲线下面积(AUC),生物利用度(F),药峰浓度(Cpk),表观容积(V)分别为0.2217h-1,,0.07461h-1,3.12h,9.30h,0.96,300.05μg·h/mL,58.55μg/mL,7.4058h和0.2863h-1,0.06786h-1,2.42h,10.21h,1.00,300.35μg@h/mL,71.74μg/mL,6.591h.     

黄连解毒散超微细粉中黄芩苷在家兔体内的药代动力学研究

采用高效液相色谱法测定灌胃给予黄连解毒散超微细粉和细粉的家兔血浆中黄芩苷的浓度,血药浓度-时间数据经药代动力学分析软件(Pharmaceutical Kinetics Software,PKS)处理,比较黄连解毒散超微细粉和普通细粉中黄芩苷在家兔体内的药代动力学参数。结果如下:黄连解毒散超微细粉组、普通细粉组黄芩苷的药代动力学最佳模型均为二室开放模型。黄连解毒散超微细粉主要药动学参数:Ka=0.497 h-1,t1/2α=2.556 h,t1/2β=8.46 h,AUC0→∞=3.401μg.h/mL,Vd=6.752 L/kg,Tpeak=3.005 h,Cmax=0.311μg/mL;黄连解毒散普通细粉主要药动学参数:Ka=0.419 h-1,t1/2α=2.74 h,t1/2β=5.83 h,AUC0→∞=2.611μg.h/mL,Vd=12.890 L/kg,Tpeak=3.645 h,Cmax=0.215μg/mL。与细粉比较,黄连解毒散超微细粉中黄芩苷的相对生物利用度提高了30.26%。上述结果表明,黄连解毒散经超微粉碎后吸收相增大,可显著提高其有效成分黄芩苷的生物利用度。     

三氧化二砷在雏鸡体内的药代动力学研究

应用新银盐法研究三氧化二砷在雏鸡体内的药物代谢动力学特征。数据经MCPKP药代动力学软件分析得出:腹腔注射三氧化二砷的药时数据符合一级吸收二室模型,动力学方程为:C=1.62916 e-0.22733t+0.15327 e-0.02024t-1.78243 e-1.36943t,其主要药代动力学参数:AUC0.13459 mg.L-1.h、Cmax 1.08215 mg.L-1、Tpeak 1.64099 h、T1/2Ka0.50605 h、T1/2α3.04841 h、T1/2β34.23920 h、Ka 1.36943 h、K120.09436 h、K210.04101 h、Kel0.11220 h。     

头孢噻呋钠在猪体内的药代动力学和生物利用度研究

用微生物杯蝶法测定血清药物浓度,6头实验猪按5 mg/kg单剂量静注、肌注头孢噻呋钠(Ceftiofur Sodium),对其药代动力学和生物利用度进行了研究.试验菌为蜡样芽孢杆菌1.1687,结果平均回收率为96.52%,血清最低检测浓度为0.15 μg/ml,日内日间变异系数为2.5%～4.9%,血清浓度在0.3～0.8 μg/ml范围内呈良好线性关系(r=0.9884).药时数据经Mcpkp药代动力学计算机程序处理,猪静注、肌注头孢噻呋钠体内药物运转都符合二室开放模型,其中静注的药代动力学参数为T1/2α=2.22 h,T1/2β=14.64 h, K12=0.09/h, K21=0.078/h, Kel=0.20/h, V1=0.34 l/kg, VB =1.38 l/kg, CLB=0.07 l/kg/h,AUC=76.56 mg/l*h; 肌注药代动力学参数为Tmax=0.69 h,Cmax=12.09 μg/ml,T1/2ka=0.19 h,T1/2β=15.18 h,Kel=0.23/h,K12=0.14/h,K21=0.08/h;生物利用度为AUCi.m/AUCi.v=87.97%.     

盐酸诺氟沙星在家蚕体内的药物动力学研究

为了给家蚕细菌病的预防和治疗提供合理用药的理论依据 ,采用微生物测定法研究了盐酸诺氟沙星在健康家蚕体内的药物动力学特征 ,以MCPKP药代动力学程序处理药时数据。结果表明 :盐酸诺氟沙星在蚕体内的药时数据符合一级吸收一室开放式模型 ,主要药物动力学参数 :T1/2Ka=1 797± 0 0 2 3h ,T1/2Kel=1 778± 0 0 12h ,Tmax=3 4 2 8± 0 0 0 8h ,Cmax=14 80 8± 0 6 4 5 μg/mL。     

兽用复方涂膜剂中蛇床子素在兔体内的药代动力学

研究复方蛇床子涂膜剂中蛇床子素在兔体内的药物代谢动力学。试验兔经透皮给药后,用高效液相色谱法以甲醇-水(80∶20)作为流动相,测定血液中蛇床子素的含量,采用3P87程序计算药物代谢动力参数。结果显示,蛇床子素经透皮给药后药代动力学符合二房室开放模型,T1/2α=3.291 h,T1/2β=25.378 h,K21=0.138 h-1,AUC=5.342μg·mL-1×h,Tmax=3.683 h,Cmax=0.162μg·mL-1。研究表明:复方蛇床子涂膜剂中蛇床子素能够透过皮肤进入血液,并维持一定的血药浓度。     

穿心莲抗炎作用的药物动力学研究

采用药理效应方法,选择大鼠炎症模型对穿心莲进行了药物动力学探讨.结果表明:其体存生物相当药量的表观药动学过程符合二室模型,其Ka=0.734 h-1,K10=0.030 h-1,t1/2(Ka)=0.944 h,t1/2(α)=0.956 h,t1/2(β)=24.869 h,AUC=95.001 g·h/ml.     

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.     

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.     

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     

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

Tropical Animal Health and Production -     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.