超高效液相色谱―串联质谱法检测猪肝中乙酰异戊酰泰乐菌素残留

本研究建立了猪肝中乙酰异戊酰泰乐菌素残留的超高效液相色谱―串联质谱检测方法(UPLC-MS/MS)。样品经EDTA-McIlvaine's缓冲液提取,HLB固相萃取柱净化后,采用C₁₈色谱柱分离,以乙腈―0.1％甲酸(7∶3,V/V)为流动相洗脱,电喷雾正离子模式电离,选择离子监测模式检测。结果表明,药物浓度与峰面积在5~2000 ng/mL范围内呈现良好的线性关系,相关系数大于0.99,对空白猪肝组织进行5~500 μg/kg的药物添加回收试验,经统计分析获得平均回收率约为84.9%~88.1%,批内变异系数为8.2％~15.1%,批间变异系数为14.7％~16.5%。本方法对乙酰异戊酰泰乐菌素的检测限为0.76 μg/kg,定量限为2.51 μg/kg,方法灵敏、准确,适用于猪肝脏中乙酰异戊酰泰乐菌素残留的检测。     

酒石酸泰乐菌素残留蛋白质检验方法的建立

酒石酸泰乐菌素是我国目前常用的一种兽用大环内酯类抗生素[1],亦称泰农、泰乐霉素,可由放线菌属弗氏链霉菌经发酵提取而得到,有泰乐菌素碱、磷酸盐和酒石酸盐3种形态。本文建立的酒石酸泰乐菌素残留蛋白质的检验方法适用于酒石酸泰乐菌素残留蛋白质的限度检测[9]。分析验证表明该方法准确、可靠,重复性好,可用于控制酒石酸泰乐菌素中残留蛋白质的检测。     

HPLC法测定酒石酸泰乐菌素及利巴韦林可溶性粉含量

采用CLC—ODSC18色谱柱,乙腈—0.05mol/L磷酸二氢钾(20∶80)为流动相,检测波长为207nm,HPLC外标法测定酒石酸泰乐菌素、利巴韦林可溶性粉中酒石酸泰乐菌素和利巴韦林含量,该法分离度大,专属性强,重复性好。     

双波长紫外分光光度法测定酒石酸泰乐菌素-盐酸多西环素可溶性粉的含量

建立了双波长紫外分光光度法同时测定酒石酸泰乐菌素-盐酸多西环素可溶性粉中酒石酸泰乐菌素和盐酸多西环素含量的检测方法。结果显示，吸收度与浓度呈良好线性关系。酒石酸泰乐菌素的平均回收率为99．90％，RSD为0．42％n=5）；盐酸多西环素的平均回收率为100．07％，RSD为0．74％（n=5）。     

液相色谱串联质谱法测定鸡蛋、牛奶和羊奶中泰乐菌素A残留的研究

建立了鸡蛋、牛奶和羊奶中泰乐菌素A残留的液相色谱-串联质谱法.样品经乙腈提取后,Prime HLB固相萃取柱净化,以0.1％甲酸水和乙腈为流动相,液相色谱-串联质谱法测定,内标法定量.试验结果表明:泰乐菌素A在1～100 ng/mL浓度范围内线性关系良好,相关系数r大于0.99;在鸡蛋、牛奶和羊奶中的检测限为2 ng/...     

孔雀石绿双波长叠加共振光散射光谱法测定酒石酸泰乐菌素含量

为了快速检测酒石酸泰乐菌素的含量,在pH值6.6 Clark-Lubs缓冲溶液条件下,孔雀石绿因构筑超分子聚集体而产生强力的共振光散射,酒石酸泰乐菌素能够与孔雀石绿阳离子发生反应,导致孔雀石绿所构筑的超分子聚集体分解,明显减弱了体系共振光散射强度,其最大的检测波长位于285 nm和332 nm。由于共振光强度(I)具有加和性,故将两个波长叠加来进行测定。酒石酸泰乐菌素的线性范围为0.2～0.6 mg/L,线性回归方程为I_RLS=5 299C-766.4,相关系数(R)为0.999 8,检测限为0.004 1 mg/L。研究表明,所建立的方法具备操作简便和灵敏度高等特点,可用于酒石酸泰乐菌素含量的测定。     

蜂蜜中的泰乐菌素

美国食品药品管理局批准兽药泰乐菌素（酒石酸泰乐菌素），我尚未获得详细材料，但收到一份报告，说在美国蜂蜜中发现了抗菌素，所幸当前发生并不普遍，涉及到的抗菌素是乳酸泰乐菌素，简称泰乐菌素。与土霉素相比，它有许多不同的特性。土霉素常写作TM，亦称羟四环素。就我所知泰乐菌素在蜂蜜中不容许有残留，这意味着它在蜂蜜中的含量无论多么小，都会受市场和法规产生影响。兽医把泰乐菌素描述成“特殊用药”。     

HPLC法测定酒石酸泰乐菌素及利巴韦林可溶性粉含量

采用CLC－ODSC18色谱柱，乙腈－0．05mol/L磷酸二氢钾（20：80）为流动相，检测波长为207nm，HPLC外标法测定酒石酸泰乐菌素、利巴韦林可溶性粉中酒石酸泰乐菌素和利巴韦林含量，该法分离度大，专属性强，重复性好。     

气相色谱法测定羊组织中溴氰菊酯残留

用气相色谱法对羊肌肉、肝脏、肾脏等组织中的溴氰菊酯残留进行检测.用石油醚、乙醚进行提取,硅胶柱净化,采用DB-5弹性石英毛细管柱(30 m×0.25 mm×0.25 μm)气相色谱法测定.溴氰菊酯标准曲线线性范围为25～1 000 ng/mL,相关系数为0.999 6,线性关系良好,在各组织中的回收率为84%～108%,适用于羊组织中溴氰菊酯残留的检测.     

微生物比浊法与管碟法测定泰乐菌素效价的评价

目的:验证比浊法测定泰乐菌素效价方法的可行性。方法:应用比浊法测定泰乐菌素效价,并对微生物比浊法、管碟法测定泰乐菌素效价的结果进行评价。结果:比浊法、管碟法效价测定结果一致。结论:比浊法具有简便、精确、快速的特点,可用于泰乐菌素及其制剂含量的测定。     

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