湿法消解-原子荧光法测定牛奶中的微量硒

采用湿法消解牛奶样品,应用氢化物发生-原子荧光光度法对3种不同品牌牛奶中的微量硒进行测定。研究发现样品消解时混酸(HNO3∶HClO4)比例为4∶1、温度在150～170℃时测得牛奶中的硒方法准确。在0～20μg/L浓度范围之间呈良好的线性关系,R=0.99912,加标回收率为96.5%～104%,相对标准偏差均小于5%。结果表明,该消解法适用于牛奶中硒含量的测定。     

无火焰石墨炉原子吸收法测定饲料中的钒

研究旨在确立无火焰石墨炉AAS法测定钒的最佳条件,用以进行饲料中钒元素的测定.通过优化钒元素在石墨炉中测定条件,利用多种不同的基体改进剂及不同的酸作为酸介质,分别测定其对钒测定结果的影响.最终确立了无火焰石墨炉AAS法测定钒的最佳条件:样品干燥温度70 ～ 150、灰化温度800～1 600、原子化温度2 700和净化温度2 800℃,300～ 500 μg/mL氯化镧为基体改进剂,4％的盐酸为酸介质.测定方法线性范围为0～0.25 μg/mL,检出极限2.08 μg/L,曲线相关系数r=0.996 2,回收率为94.54％～97.42％,相对标准偏差为1.5％～2.1％.该法用于饲料中微量钒的测定结果满意.     

微波消解石墨炉原子吸收光谱法测定植物中的铅

研究了微波消解石墨炉原子吸收分光光度法测定植物中铅的最佳实验条件、测定方法的准确度和精确度。结果表明,测定植物中铅的最佳酸体系为5 mL HNO3-3 mL H2O2-2 mL HF、最佳消解条件为微波炉功率600 W、温度180℃消解15 min,石墨炉的最佳工作条件为90℃干燥45 s、900℃灰化20 s、原子化温度1 400℃和洁净温度2 500℃。用该法样品加标回收率为95.81%~100.09%,检出限为0.068 4mg/kg,相对标准偏差为1.2%~5.6%。     

原子荧光光谱法测定饲料中微量元素硒

测定微量元素硒的常用方法有荧光法、原子吸收法和比色法等,荧光法虽然准确但繁琐,不仅所用试剂DAN毒性大而且需进口;原子吸收法火焰法灵敏度低,石墨炉法有严重的基体干扰;比色法虽然简便但灵敏度低,原子荧光法是一种简便及灵敏度高的方法.用原子荧光法测定饲料添加剂及预混料中微量元素硒,硒的相对标准偏差为1.2%,检出限为0.4 ng/mL,线性范围为0～400 ng/mL,相关系数为0.999 91,回收率为96.1%～101.8%.     

复方口腔溃疡贴膜剂中醋酸地塞米松的含量测定

建立反相高效液相色谱法测定复方口腔溃疡贴膜剂中醋酸地塞米松的含量。方法：采用安捷伦C18色谱柱(218mm×4.6mm,5μm),甲醇-乙腈-水(25：20：55),检测波长为240nm,流速为1.0ml/min,柱温为30℃。醋酸地塞米松在18~60μg·mL-1范围内呈良好的线性关系(r=0.99995)。醋酸地塞米松平均回收率分别为99.3豫。结论：本法简便、准确,可用于复方口腔溃疡贴膜剂中醋酸地塞米松的含量测定。     

饲料添加剂中微量游离铜的极谱测定

提出在H2O4-EDTA-KNO3-明胶体系中以单扫描极谱测定饲料添加剂中微量游离铜的方法.用硝酸浸取法提取试样中的游离铜.铜的极谱峰电位为-0.2V(相对饱和甘汞电极).铜浓度在0.1～100μg/mL范围内与峰电流呈良好的线性关系.检出限为0.04 μg/mL,RSD为3.3%,加标回收率为97%.该方法简便、快速、测定精度好,可用于实际样品的测定.     

氯地乳膏中氯霉素和醋酸地塞米松的含量测定

本文采用高校液相测定了氯地乳膏中氯霉素和醋酸地塞米松的含量,固定相为：安捷伦Cl8(4.6mm×250mm,5μm),甲醇-乙腈-0.025mol/L磷酸二氢钠(25：25：50)为流动相,检测波长为240nm;醋酸地塞米松在10~100μg·mL-1范围内呈良好的线性关系;氯霉素在50~500μg·mL-1范围内呈良好的线性关系。醋酸地塞米松和氯霉素的平均回收率分别为99.5%、99.5%,RSD为0.86%(n=6)、0.83%(n=6);此方法简便、准确、重现性好,可用于氯地乳膏中醋酸地塞米松和氯霉素的含量测定。     

“一针肥注射液”中微量元素含量测定方法的建立

目的：建立＂一针肥注射液＂中微量元素的含量测定方法。方法：采用火焰原子吸收分光光度法测定＂一针肥注射液＂中铁、锌、铜、硒、钴的含量。结果：铁、锌、铜、硒、钴的线性范围分别为0.053~0.385μg/mL、0.25~2.50μg/mL、0.5~8.0μg/mL、10.0~100.0ng/mL、5.0~50.0ng/mL,平均回收率分别为100.35%、99.95%、99.51%、98.49%、100.51%。结论：本法可以准确测定＂一针肥注射液＂中铁、锌、铜、硒、钴的含量,该法简便、快速、准确可靠。     

氯地乳膏中氯霉素和醋酸地塞米松的含量测定

本文采用高校液相测定了氯地乳膏中氯霉素和醋酸地塞米松的含量,固定相为:安捷伦Cl8(4.6mm×250mm,5μm),甲醇-乙腈-0.025mol/L磷酸二氢钠(25:25:50)为流动相,检测波长为240nm;醋酸地塞米松在10~100μg·m L-1范围内呈良好的线性关系;氯霉素在50~500μg·m L-1范围内呈良好的线性关系。醋酸地塞米松和氯霉素的平均回收率分别为99.5%、99.5%,RSD为0.86%(n=6)、0.83%(n=6);此方法简便、准确、重现性好,可用于氯地乳膏中醋酸地塞米松和氯霉素的含量测定。     

鸡补硒过量的防治方法

正1)预防。坚持微量间断补硒是防止鸡补硒过量引起硒中毒的有效方法。给鸡补硒的方法如下。(1)注射0.005%的亚硒酸钠溶液(0.1%亚硒酸钠1 mL加19 mL灭菌水)1 mL/只,1次注射即可。(2)在鸡1~3日龄、20~23日龄、40~43日龄时以1~2 mg/L的亚硒酸钠溶液饮水或拌料内服,连续饲喂3 d,可预防鸡缺硒症。如果同时在饲料中添加足量的维生素E、含硫氨基酸、抗氧化剂等,则补硒效果更好。     

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