高效液相色谱法测定猪血浆中多西环素的含量

建立了高效液相色谱法测定猪血浆中多西环素含量的方法.采用Agillent 1100 HPLC系统,分析柱为ZORBAX SB C-18,流动相组分为超纯水(含0.6 mmoL/L EDTA·2Na,0.15%三氟乙酸,10 mmoL/L草酸)和乙腈,梯度洗脱,柱温15℃,检测波长350 nm.猪血浆样品经EDTA-McIlvaine缓冲液和20%(V/V)高氯酸的混合液缓中变性处理,取上清液直接进样测定.结果表明,血浆中多西环素的线性范围为0.10～12.80μg/mL,其方程为y=49.846 x-0.289,相关系数为0.999 2(n=8);空白血浆添加低、中、高浓度多西环素(0.10、0.80、6.40μg/mL)样品的平均回收率分别为94.0%、98.2%、100.5%(n=4);平均批内变异系数分别为2.8%、4.1%和1.2%(n=4),批间变异系数分别为6.5%、9.4%和3.4%(n=16).本方法样品前处理简单、快速,结果准确、可靠,适用于猪血浆中多西环素含量的测定及相关药代动力学研究.     

HPLC法测定猪体内双氯芬酸的血药浓度

建立猪血浆中双氯芬酸含量的HPLC测定法。猪血浆中双氯芬酸采用正己烷-异丙醇混合溶液(90∶10,V/V)提取,HPLC紫外检测器检测。色谱柱为C18柱,流动相为甲醇-15g/L乙酸水溶液(80∶20,V/V),测定波长为276nm。外标法定量。结果表明,血浆中杂质不干扰双氯芬酸的测定,双氯芬酸血药浓度在0.025μg/mL~20.0μg/mL范围内线性关系良好(R2=1),最低定量限为0.05μg/mL,高、中、低空白血浆添加样品浓度的日内变异系数和日间变异系数分别小于4%和6%,回收率为85%~97%。结果表明,该方法适用于猪血浆中双氯芬酸含量的测定,可用于含双氯芬酸钠的制剂在猪体内的药物代谢动力学和生物利用度研究。     

盐酸环丙沙星注射液的高效液相色谱测定

建立测定盐酸环丙沙星注射液中盐酸环丙沙星含量的高效液相色谱检测方法。色谱柱为Gemini C18110A(250 mm×4.60 mm,5μm),流动相为0.025 mol/L磷酸溶液(用三乙胺调pH至3.0±0.1)-乙腈(75∶25),检测波长277 nm,流速1.0 mL/min,进样量10μL。在12.5μg/mL~200μg/mL浓度范围内,盐酸环丙沙星的峰面积与浓度呈良好的线性关系,相关系数为0.999 4(n=5),平均回收率为99.58%。该方法简便、准确、灵敏,可用于测定盐酸环丙沙星注射液的含量。     

RP-HPLC法测定阿莫西林-盐酸环丙沙星可溶性粉的含量

应用RP-HPLC法测定阿莫西林-盐酸环丙沙星可溶性粉的含量.采用Shim-pack CLC-ODS C18柱(150 mm×6 mm, 5 μm),以1.5×10-2 mol/L三乙胺溶液(用磷酸调pH至3.0)-乙腈 (体积比85∶ 15)为流动相,流速为1.0 mL/min,检测波长为229 nm,柱温为40 ℃.在此色谱条件下两者能完全分离,阿莫西林、盐酸环丙沙星分别在22～108 μg/mL和29～146 μg/mL范围内峰面积与浓度呈良好的线性关系,相关系数均为0.999 9.阿莫西林、盐酸环丙沙星的回收率分别为99.50%～100.20%和99.30%～99.86%(n=5);RSD分别为0.60%～1.00%和0.86%～1.02%(n=5).本法可用于阿莫西林-盐酸环丙沙星可溶性粉的质量控制.     

高效液相色谱法测定饲料中喹乙醇含量

利用高效液相色谱法测定饲料中喹乙醇含量.采用C18色谱柱,以0.02 mol/L磷酸‐甲醇(85∶15)为流动相,流速为0.8 mL/min,检测波长为380 nm.喹乙醇在0.1~100 μg/mL范围内线性关系良好,r＝0.999 904;经5种不同浓度回收率的测定,其回收率在85.5%～93.6%之间,RSD小于5.2%(n=5).     

高效液相色谱法测定猪血浆及组织中喹赛多及其脱二氧代谢物

建立了测定猪血浆及肝脏、肾脏、肌肉等组织中的喹赛多及其代谢物脱二氧喹赛多的高效液相色谱(HPLC)法.血浆样用甲醇沉淀蛋白后离心取上清液进样测定.组织样先用乙腈匀浆,用正己烷脱脂后作HPLC检测.色谱柱为ODS C18柱;流动相血浆样测定为乙腈水(2080),组织样测定为甲醇水(4258),流速为1.0 mL/min;紫外检测波长305 nm.药物工作液质量浓度范围为0.005～0.500 mg/L时,血浆样品及组织样品测定条件下药物质量浓度与响应值均具良好线性关系,相关系数＞0.999.血浆中药物质量浓度为0.02、0.10、0.50 mg/L时,喹赛多及脱二氧喹赛多的回收率均大于70%,组织中药物含量为0.05、0.20、1.00μg/g时,肌肉样品的回收率均大于70%,肝脏、肾脏样品则为50%～80%.本试验条件下,喹赛多及其脱二氧代谢物的最低检出质量浓度,血浆样品分别为0.01、0.02mg/L,组织样品2种检测物均为0.025μg/g.测定了工作液3种质量浓度0.01、0.05、0.25 mg/L的仪器精密度,日内相对偏差＜8.0%,日间相对偏差＜17.0%.     

高效液相色谱法测定猪血浆中氟苯尼考的含量

建立了猪血浆中氟苯尼考含量测定的高效液相色谱法(HPLC)。采用C18色谱柱(4.6mm×250mm,5μm),以乙腈-水(24:76)为流动相,流速1.0mL/min,检测波长223nm,进样量20μL,柱温为25℃。氟苯尼考浓度在0.1～16μg/mL时,标准曲线线性关系良好(r0.9998),无杂质干扰,回收率高于94%,批内变异系数和批间变异系数均低于5%。本方法操作简便,分析快速,结果准确,适用于猪血浆中氟苯尼考含量的测定及相关药代动力学研究。     

高效液相色谱法测定头孢噻呋钠含量

建立了测定头孢噻呋钠含量的高效液相色谱法。采用C18色谱柱(4.6mm×250mm,5μm),以含0.8%四正丁基溴化铵的乙腈溶液-0.1mol/L柠檬酸钠溶液(用20%柠檬酸调节pH至5.0)-磷酸盐溶液(0.1mol/L磷酸二氢钾,0.02mol/L磷酸氢二钾,用10mol/L氢氧化钾调节pH至7.0)-水(400:4:48:520)为流动相,流速1.0mL/min,检测波长254nm,进样量20μL,柱温30℃。头孢噻呋钠浓度在0.0496～0.1984mg/mL时,其峰面积与浓度的线性关系良好(r=1.000);平均回收率为100.0%,平均相对标准偏差RSD为0.17%;检测限为0.0025μg/mL。本方法操作简便,分析快速,结果准确,适用于头孢噻呋钠原料药的含量测定。     

鸡蛋中阿莫西林残留HPLC-DAD检测方法的建立

为了能够准确地测定鸡蛋中阿莫西林的残留,本试验建立了高效液相色谱-二级管阵列检测器(HPLC-DAD)方法来检测鸡蛋中阿莫西林残留。采用乙腈沉淀蛋白提取鸡蛋液中的阿莫西林,以超纯水饱和的二氯甲烷作为进一步萃取纯化的溶剂,0.01 mol/L磷酸二氢钾溶液(pH=5.5)和乙腈溶液为流动相,流速为1.0 mL/min,检测波长为230 nm,样品进样量为20μL,柱温为30℃的色谱条件对鸡蛋中阿莫西林残留进行检测。结果显示,阿莫西林的质量浓度范围为0.05～100.00μg/mL,与峰面积具有良好的线性关系(R²=0.999 8);该方法的重复性、精密度和稳定性均良好,相对标准偏差在2.0%以内;平均加样回收率介于82.89%～89.92%,相对标准偏差介于1.68%～2.71%;阿莫西林检测限为0.025μg/mL,定量限为0.050μg/mL。结果表明,本试验所建立的HPLC-DAD方法操作过程简便、稳定性好、灵敏度高,可适用于鸡蛋中阿莫西林残留的准确检测。     

HPLC法测定猪血浆中帕托珠利的方法学建立

建立了HPLC法测定猪血浆中帕托珠利含量的方法。色谱柱为安捷伦ZORBAX Eclipse XDB-C18柱(250 mm×4.6 mm,5μm),流动相0.2%乙酸水溶液-乙腈(47∶53),柱温35℃,流速为1 m L/min,检测波长为250 nm。在本方法条件下,帕托珠利在0.1～10μg/m L浓度范围内线性关系良好(r0.999),检测限(LOD)为0.04μg/m L,定量限(LOQ)为0.1μg/m L,批内和批间回收率均大于90%,批内和批间精密度RSD均小于9%。本方法简单、准确、快速,可用于测定猪血浆中帕托珠利的含量。     

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