左旋咪唑对鸡细胞免疫和体液免疫功能的作用

系统研究了左旋咪唑对鸡细胞免疫和体液免疫功能的作用。结果表明左旋咪唑可影响正常鸡的免疫功能 :左旋咪唑可显著促进鸡外周血T淋巴细胞增殖 ,但对B淋巴细胞无明显影响 :2 5～ 1 0mg/kg左旋咪唑可使CD+4/CD+8淋巴细胞比值明显升高 ;左旋咪唑可使鸡体内抗颗粒性、胸腺依赖性抗原SRBC抗体滴度 ,抗可溶性、胸腺依赖性抗原BSA抗体滴度和抗非胸腺依赖性抗原BA抗体滴度均明显升高 ;2 5～ 1 0mg/kg左旋咪唑可使鸡血清总补体活性明显升高。左旋咪唑影响正常鸡回忆性免疫应答反应 :左旋咪唑 ( 1 0mg/kg)可使二次免疫鸡抗SRBC抗体滴度和抗BA抗体滴度回忆性免疫应答反应明显升高 ;但使鸡对抗BSA抗体滴度回忆性免疫应答反应明显降低。     

甲硝唑对鸡回忆性体液免疫应答反应的作用

本试验系统观察了甲硝唑对鸡回忆性体液免疫应答反应的作用,并与咪唑类化合物左旋咪唑进行了比较。28日龄鸡,免疫注射绵羊红细胞 牛血清白蛋白(SRBC BSA)悬液,或稀释的布氏杆菌(BA)抗原。56日龄时,以10.0、100.0mg/kg甲硝唑或10.0mg/kg 左旋咪唑饮水给药,连用3d,给药第二天同时进行第二次免疫注射。结果表明甲硝唑(10.0~100.0mg/kg)可使鸡体内对颗粒性胸腺依赖性抗原SRBC和非胸腺依赖性抗原BA抗体滴度回忆性免疫应答反应明显升高;但使鸡对可溶性胸腺依赖性抗原BSA抗体滴度回忆性免疫应答反应明显降低。与甲硝唑比较,左旋咪唑(10.0mg/kg)也存在着非常类似的作用。     

左旋咪唑对地米塞松预处理鸡免疫功能的影响

系统观察了左旋咪唑对地塞米松预处理鸡免疫状态的作用。结果表明地塞米松明显抑制鸡免疫功能，抑制鸡外周血淋巴细胞IL－2活性，可使体内抗SRBC抗体滴度、抗BA抗体滴度、抗BSA抗体滴度、血清总补体活性（CH50）降低。10mg/kg左旋咪唑可拮抗地塞米松对鸡外周血淋巴细胞IL－2活性的抑制作用，可拮抗地塞米松对鸡体内抗SRBC抗体、抗BSA抗体和抗BA抗体产生的抑制，也可明显拮抗地塞米松对鸡体内补体产生的抑制作用，使地塞米松抑制免疫鸡外周血淋巴细胞IL－2活性、产生抗体和产生补体恢复至或超过正常鸡水平。     

左旋咪唑对地塞米松预处理鸡免疫功能的影响

系统观察了左旋咪唑对地塞米松预处理鸡免疫状态的作用.结果表明地塞米松明显抑制鸡免疫功能,抑制鸡外周血淋巴细胞IL-2活性,可使体内抗SRBC抗体滴度、抗BA抗体滴度、抗BSA抗体滴度、血清总补体活性(CH50)降低.10mg/kg左旋咪唑可拮抗地塞米松对鸡外周血淋巴细胞IL-2活性的抑制作用,可拮抗地塞米松对鸡体内抗SRBC抗体、抗BSA抗体和抗BA抗体产生的抑制,也可明显拮抗地塞米松对鸡体内补体产生的抑制作用,使地塞米松抑制免疫鸡外周血淋巴细胞IL-2活性、产生抗体和产生补体恢复至或超过正常鸡水平.     

几种化学合成类免疫增强剂在鸡病中的应用

1左旋咪唑左旋咪唑是具有免疫调节作用的人工合成化合物,具有广泛的免疫调节活性,可促进细胞和体液免疫。左旋咪唑能增强鸡体液免疫应答反应,使鸡抗胸腺依赖性抗原抗体滴度、抗非胸腺依赖性抗原抗体滴度均明显升高。     

西咪替丁对鸡回忆性体液免疫应答反应的作用

枯试验系统观察了西咪替丁对鸡回忆性体液免疫应答反应的作用，并与同类咪唑类化合物左旋咪只进行了比较，28日龄鸡，免疫注射绵羊红细胞＋牛血清白蛋白（SRBC＋BSA）悬液，或稀释的布氏杆菌（BA）抗原。56日龄时，以10．0、100．0mg/kg西咪替丁或10．0mg/kg左旋咪唑饮水给药，连用3天，给药第二天同时进行2次免疫注射。结果表明西咪替丁（10．0－100mg/kg)可使二次免疫鸡体内对颗粒性胸腺依赖性抗原SRBC和非胸腺依赖性抗原BA抗体滴度回忆性免疫应答反应明升高，但使鸡对可溶性胸腺依赖性抗原BSA抗体滴回忆性免疫应答反应明显降低。与西咪替丁比较，左旋咪唑（10．0mg/kg)也存在着非常类似的作用。     

免疫增强剂的研究应用（下）

5，化学合成类 左旋咪唑左旋咪唑是第一个被发现具有免疫调节作用的人工合成化合物，具有广泛的免疫调节活性，可促进细胞免疫和体液免疫，增强正常鸡体体液免疫应答反应，使鸡抗胸腺依赖性抗原抗体滴度、抗非胸腺依赖性抗原抗体滴度均明显升高。左旋咪唑对鸡新城疫疫苗、马立克疫苗和鸡传染性法氏囊疫苗均有免疫增强作用。     

甲硝唑对地塞米松预处理鸡免疫功能的影响

对地塞米松预处理鸡投以10mg／kg剂量的甲硝唑，观察后者对前者作用的影响。结果表明：地塞米松明显抑制由伴刀豆球蛋白A(ConA)引起的鸡外周血淋巴细胞(PBL)产生IL-2活性，而甲硝唑对这种抑制作用有显著的拮抗作用；地塞米松能抑制鸡对绵羊红细胞(SRBC)悬液和牛血清白蛋白(BSA)两种胸腺依赖性抗原的免疫应答和对布鲁氏菌非胸腺依赖性抗原的抗体应答，但甲硝唑会逆转这种抑制作用；甲硝唑能封闭地塞米松对补体产生的抑制作用。对比实验结果同时表明，在拮抗地塞米松对鸡免疫功能负面影响方面，左旋咪唑与甲硝唑作用非常类似。     

甲硝唑对鸡新城疫病活疫苗免疫效果影响的观察

本研究进行观察甲硝唑药物对鸡ND疫苗初次免疫的影响。结果显示高母源抗体雏鸡免疫ND疫苗前应用甲硝唑，用药鸡免疫后抗NDV抗体滴度明显升高；免疫后应用甲硝唑，抗NDV抗体滴度也明显高于未用药鸡；左旋咪唑具有类似作用。甲硝唑用药鸡ND疫苗二次免疫后，鸡血清抗NDV抗体滴度明显高于未用药鸡；左旋咪唑也具有类似作用。     

左旋咪唑对鸡离体外周血淋巴细胞的作用

本文报道了左旋咪唑对鸡离体外周血淋巴细胞（PBL）增殖及伴刀豆球蛋白A（ConA)诱导细胞（CIC）活性的作用；左旋咪唑以剂量依赖性方式促进鸡PBL的增殖；与ConA对促进鸡PBL增殖呈现协同作用；对脂多糖（LPS）激活鸡PBL具有明显促增殖作用；可逆转磷酸组胺和肾上腺素对ConA和LPS激活鸡PBL增殖的抑制作用；低浓度左旋咪唑不能逆转氢化可的松对ConA激活鸡PBL增殖的抑制作用，但高浓度（100-400μg/ml）可明显逆转氢化可的松的抑制作用；左旋咪唑可明显逆转氢化可的松的对LPS激活鸡PBL增殖的抑制作用；可促进CD4^ 细胞增殖，抑制CD8^ 细胞增殖，使CD4^ /CD8^ 细胞比值升高，CIC活性增强。     

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