实验感染肝片吸虫山羊和大鼠血清花生四烯酸代谢物的变化研究

实验一选择9只健康、6-10月龄雄性白山羊，经粪便学检查和Dot-ELISA检测，确认无肝片吸虫感染，随机分成感染组（n=5)和对照组（n=4)，试验组每只一次口服接种150个肝片吸虫囊蚴，每周定时从颈静脉采集感染前（0周）和感染后23周山羊血液一次，分离血浆，实验二将60只大鼠随机分成感染组（n=30)和对照组（n=30)，感染组大鼠一次口服25个囊蚴，对照组不感染，于感染前（0周）和感染后（1，3，5，7，9周）采集血样，分别测定试验组和对照组羊和鼠花生四烯酸代谢物6-酮-前列腺素F1α（6-keto-PGF1α）和血栓素B2（TXB2）的变化。结果表明肝片吸虫感染后，山羊血浆中TXB2水平变化，在1-3周与对照组相比无显著差异，从第5周开始到实验结束，试验组血浆中TXB2水平均显著或极显著地高于对照组，大鼠血栓素水平在感染后前5周逐步下降，以后急剧上升，至实验结束时显著高于对照组；而整个实验期间，两种动物血浆中6-keto-PGF1α水平变化不显著，提示肝片吸虫感染后，机体发生多种功能的改变，花生四烯酸代谢物参与了肝片吸虫病的发展过程。     

实验感染肝片吸虫山羊的病理生理学——Ⅲ.细胞因子水平的变化

试验选择6只健康白山羊（经粪便学检查和Dot-ELISA检测，确认无肝片吸虫感染）随机分成Ⅰ、Ⅱ、Ⅲ组，其中Ⅰ、Ⅱ组山羊每只分别1次口服接种200、500个肝片吸虫囊蚴，Ⅲ组作为不感染对照组，每周颈静脉采血1次，连续11周，检测肝片吸虫感染后山羊血清中IL-2、TNF-α水平的变化和外周血淋巴细胞分泌IL-2的能力。结果表明，山羊试验感染肝片吸虫后，Ⅰ组山羊血清IL-2水平在感染后有所下降，而Ⅱ组山羊血清IL-2水平在感染后有所升高；感染不同剂量肝片吸虫的山羊血清TNF-α水平和淋巴细胞IL-2分泌水平均有不同程度的升高，在感染后第1周淋巴细胞就有反应，并且对非特异性刺激原和特异性刺激原的应答都有显著升高。这一结果提示，TNF-α可能参与肝片吸虫对肝的损伤过程，肝片吸虫感染剂量对宿主的IL-2含量影响较大，同时IL-2在宿主防御免疫中有重要作用。     

肝片吸虫感染对山羊机体自由基代谢影响的研究

实验选择9只健康、6－10月龄雄性白山羊，经粪便学检查和Dot-ELISA检测，确认无肝片吸虫感染，随机分成感染组（n=5)和对照组（n=4)，试验组每只1次口服接种150个肝片吸虫囊蚴，每周定时从颈静脉采集感染前（0周）和感染后15周血液1次分离血清。测定血清谷胱甘肽过氧化物酶（GSH－Px)活性、超氧化物歧化酶（SOD）活性、过氧化物酶（CAT）活性、丙二醛（MDA）和一氧化氮含量的变化，结果表明肝片吸虫感染后血清中GSH－Px活性除第8周试验组显著高于对照组，其他各周无显著差异；在整个实验期间，试验组山羊血清中SOD活性在1－5周呈波动状，以后两组基本处于同一水平；试验组山羊血清CAT活性在感染后第3周显著低于对照组，第6－15周时，试验组始终高于对照组，但各周差异均不显著；试验组山羊血清中MDA含量在整个实验期间始终呈波动状，而在第8、9周试验组显著高于对照组，中周与对照组相比无显著差异；感染后试验组血清中NO开始下降，并且显著低于对照组，至第3－6周时试验组显著高于或低于对照组，第6－15周，试验组一直高于对照组，并在第7、10周时显著地高于对照组。提示山羊感染肝片吸虫后，机体发生多种功能的改变，机体的自由基产生与清除处于相互对抗之中，机体的自由基代谢参与了肝片吸虫病的发展过程。     

急性感染肝片吸虫水牛的某些免疫反应研究

本实验选用12头体重为300－500kg，年龄2－3岁的雄性去势水牛，经粪便检查和Dot-ELISA检测确认为无肝片吸虫感染后，随机分为感染组（n=9）和对照组（n=3）。感染组每头水牛1次性经口感染1600个肝片吸虫囊蚴。实验期间由专人饲养，自由采食青干草和饮水。每周定时颈静脉采血，测定外周血淋巴细胞增殖反应、白细胞介素－2（IL－2）水平、T和B淋巴细胞比例、IgG水平以及血清蛋白总量和比例。结果表明：感染组水牛的T淋巴细胞刺激指数在感染后2－8周高于对照组，但刺激指数和IL－2与对照组均无显著性差异。感染组水牛的外周血T淋巴细胞比例从感染后第1周显著下降，以后一直在低于对照组水平波动，而淋巴细胞从感染后第1周开始显著升高，且一直在高于对照组范围内波动。感染组水牛的α-球蛋白、β－球蛋白与对照组相比均无显著性差异，而白蛋白从第5周开始显著下降，以后维持在低于对照组的水平范围波动；γ－球蛋白从第5周显著高于对照组，以后于对照组范围波动。感染组水牛的抗ES抗原（分泌－排泄抗原）的IgG抗体水平从第2周升高，并持续至实验结束。结果提示：体液免疫应答反应是水牛抗肝片吸虫感染的重要机制。     

实验感染肝片吸虫山羊血液T、B淋巴细胞比例及激素水平变化

为了深入了解动物感染肝片吸虫后免疫细胞和内分泌活动的变化，将6只健康山羊均分为感染Ⅰ、Ⅱ组及对照组。Ⅰ、Ⅱ组分别一次性口服感染肝片吸虫囊蚴200、500个／只，试验期17周，每周定时采血，测定血浆T、B淋巴细胞比例、皮质醇、胰岛素、甲状腺激素（T3、T4）等。结果表明，Ⅰ、Ⅱ组山羊T淋巴细胞（％）分别从感染后4、6周开始低于或显著低于对照组，直至17周；而淋巴细胞（％）变化与之相反。Ⅰ、Ⅱ组山羊血浆皮质醇变化较大，总体水平高于对照组；T3、T4水平从第4周开始逐渐低于对照组，且在极低的水平上变动；Ⅰ、Ⅱ组胰岛素水平与对照组相近。揭示山羊急性感染肝片吸虫后，内分泌活动紊乱，体内细胞免疫反应抑制，而体液免疫反应增加，表现出山羊对肝片吸虫感染的耐受力和抵抗力较弱的特点。     

实验感染肝片吸虫山羊的病理生理学Ⅰ．血液生理生化指标及抗体动态

给山羊分别实验感染肝片吸虫囊蚴200、500个／只，感染后每周颈静脉采血1次，测定血液生理生化指标和抗体动态的变化。结果表明，山羊实验感染肝片吸虫后，血液中RBC、Hb明显下降；WBC和嗜酸性粒细胞数显著增加；血清中谷－草转氨酶（AST）从第2周开始上升，第8周和第9周达到峰值；γ-谷氨酰转肽酶（GGT）于感染后第7周和第8周开始升高，第10周和第11周达高峰；以ELISA检测抗体表明，2个试验组山羊感染后血清中IgG分别在第9周和第6周达峰值，随后均稍有下降，一直呈波动趋势，但在整个试验期内，一直高于对照组（P＜0．05或P＜0．01）。分析认为，山羊感染肝片吸虫后表现的贫血是正细胞正色素型，伴有低白蛋白性，肝脏损伤明显，体液免疫反应增强。     

水牛实验感染肝片吸虫后IGF-Ⅰ和β内啡肽含量变化及其对免疫功能的影响

头健康阉公水牛, ５ 头经口每日感染肝片吸虫囊蚴６０ 个／ 头, 连续２０ ｄ ; ３ 头不感染作对照。于感染前和感染后每周采集颈静脉血样１次, 共２７ 次, 分别测定血浆 Ｉ Ｇ Ｆ Ⅰ、β内啡肽 （β Ｅ Ｐ） 以及 Ｗ Ｂ Ｃ 、 Ｄ Ｃ ; Ｔ、 Ｂ 淋巴细胞比例和血清抗肝片吸虫 Ｉｇ Ｇ 水平。结果 Ｉ Ｇ Ｆ Ⅰ和β Ｅ Ｐ 分别在开始感染后第５ 周和第４ 周显著升高, 并持续到第２３ 周和第９ 周; Ｉｇ Ｇ 水平也在第４ ～２２ 周显著高于对照组, 嗜酸性粒细胞和 Ｂ 淋巴细胞比例也明显升高。结果表明肝片吸虫感染后水牛免疫功能的变化可能与 Ｉ Ｇ Ｆ Ⅰ及β Ｅ Ｐ 有关。     

Closantel缓释剂对实验感染肝片吸虫山羊机体自由基影响的研究

选用5只实验感染肝片吸虫山羊研究Closantel缓释剂对机体抗氧化功能的影响，实验用山羊每只一次性口服肝片吸虫囊蚴150个，感染后第15周随机将山羊分成对照组（n=2）和驱虫组（n=3），驱虫组每羊口服两颗Closantel缓释剂，每周定时采集颈静脉血液，检测血清抗氧化酶的变化，观察服用Closantel缓释剂对其的影响。结果表明投药后山羊血清中GSH－Px、CAT均有不同程度的升高，SOD变化不显著，而脂质过氧化产物MDA含量则下降，提示Closantel的缓释剂型对实验感染肝片吸虫山羊机体的抗氧化产生了影响，对机体有一定保护作用。     

实验肝片吸虫感染对大鼠机体自由基代谢影响的研究

通过大鼠感染肝片吸虫复制感染模型 ,研究肝片吸虫感染后血清抗氧化功能的变化。 60只大鼠随机分成感染组和对照组 ,每组 30只。感染组大鼠一次口服 2 5个囊蚴 ,对照组不感染。于感染前 (0周 )和感染后 (1 ,3,5,7,9周 )采集血样 ,检测感染后谷胱甘肽过氧化物酶(GSH Px)、超氧化物歧化酶 (SOD)、过氧化物酶 (CAT)活性和丙二醛 (MDA)含量的变化。结果表明大鼠感染肝片吸虫后 ,感染组血清中GSH Px先升高后下降 ,SOD活性无明显变化 ,CAT活性在感染后下降 ,MDA含量在前 5周变化不明显 ;说明自由基参与了肝片吸虫病的发病过程     

山羊感染肝片吸虫后血浆肿瘤坏死因子-α和花生四烯酸代谢物动态变化初探

选用 6只健康雄性山羊 ,经粪便检查和 Dot- ELISA检测确认为无肝片吸虫感染。随机分成感染 组、感染 组和对照组 ( 组 ) ,每组 2只。 、 组山羊分别一次口服接种 2 0 0和 50 0个囊蚴 ,实验连续 1 7周。每周定时由颈静脉采血样 ,测定血浆肿瘤坏死因子 - α(TNF- α)和花生四烯酸代谢物水平动态变化及相互关系。结果表明 :山羊从感染后第 5周开始 TNF- α和 PGE2 逐渐上升 ,高于或极明显高于对照组直至 1 7周。山羊感染后第 3周 组 TXB2 明显高于对照组 ,以后呈波动性上升趋势直至第 1 7周的最大值 ,感染 组没有类似 组的表现 ,与对照组相近。在整个实验期里 ,感染组山羊血浆 6- keto- PGF1α水平低于对照组 ,但差异不显著。检验感染组的 TNF-α与几种花生四烯酸代谢物水平间的相关性发现 :感染 和 组的 TNF- α均与 PGE2 呈显著正相关。提示山羊急性感染肝片吸虫后 ,体内 TNF- α和一些花生四烯酸代谢物明显参与了山羊肝片吸虫病的发生发展过程 ,表现出山羊对肝片吸虫感染的耐受力和抵抗力较弱的特点     

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