家兔实验感染伊氏锥虫的免疫反应和病理变化

伊氏锥虫病在世界范围内流行，侵袭牛、马、骆驼等家畜，对畜牧业危害严重。动物感染伊氏锥虫后，机体能产生强烈的兔疫应答，但由于锥虫不断改变其表而糖蛋白结构，产生免疫逃避，因而机体不能最终清除锥虫的感染[1]。机体的免疫反应具有免疫保护和免疫病理两种作用，国内这方面的研究尚不多见。我们实验感染家兔，同时检测家兔的免疫反应和观察家兔的病理变化，旨在初步探讨兔疫反应在锥虫感染中的作用以及锥虫病的致病机理，为伊氏锥虫病的免疫学和病理学提供资料。1材料和方法1．1实验动物：小鼠，雄性家兔。购于解放军农牧大学实验动物…     

在吸血蝇体内发现伊氏锥虫前鞭毛期虫体

最后，我们在实验室孽生的吸血蝇体内意外地发现了伊氏锥虫前鞭毛期虫体，通过人工感染小鼠试验，从小鼠血液中查见大量伊氏锥虫。说明伊氏锥虫若遇到合适媒介，还存在生物学传播的可能。     

伊氏锥虫不同地理株对小鼠致病性的比较试验

伊氏锥虫是地理分布广泛的锥虫，可以引起骆驼、马、黄水牛、犬和大小鼠等动物的伊氏锥虫病，宿主中以马、犬和大小鼠等为高度易感动物，感染后往往发病急，死亡快，由于其因地理和宿主条件的不同而表现出感染力和毒力的差异[1]，我们进行了不同地理株对小鼠的感染力及其毒力的比较观察。材料和方法材料1、伊氏锥虫：伊氏锥虫云南株于1987年在宜良分离自云南水牛体内，广东株于1981年在阳江分离自广东水牛体内，安徽株分离自安徽水牛体内，江苏株分离自江苏高邮水牛体内，新疆株分离自新疆骆驼体内，以上伊氏锥虫都经小鼠繁殖后保存于液氮中…     

应用间接血凝试验检测伊氏锥虫循环抗原

利用间接血凝试验,对人工感染伊氏锥虫的马、豚鼠,家兔的循环抗原(CA)及其出现规律进行了实验检测。结果,感染动物47/57 CA阳性,15分份锥虫培养液CA全为阳性,而健康动物及空白培养液均为CA阴性。伊氏锥虫CA与锥虫属以外的驽巴贝西虫,传贫、鼻疽等血清不交叉,而与锥属的牛泰氏锥虫、路氏锥虫、马媾疫锥虫的血清有不同程度的交叉反应。CA比抗体出现早;感染动物完全治愈后,CA消失,而未彻底治愈者,CA仅暂时消失,但不久又出现,直到动物病死,由此认为,CA的检测可作为早期诊断、疗效判定和预后判定的依据之一。     

应用单克隆抗体检查伊氏锥虫抗原变异

用广西骡株伊氏锥虫可溶性抗原免疫的BALB/C小鼠脾细胞与小鼠骨髓瘤细胞(SP_2/O)融合,获得了在ELISA中能与广西骡株伊氏锥虫可溶性变异表面糖蛋白反应的2个分泌IgG_1的单克隆抗体(McAb)。用McAb于ELISA抑制试验对四份不同期的广西骡株伊氏锥虫阳性血清的抗体成分进行了分析,结果四份锥虫阳性血清对于McAb与相应抗原决定簇的结合均未出现明显的抑制作用。表明血清样本间很少或完全没有与McAb相类似的抗体。这证明伊氏锥虫存在多个血清型亦即变异抗原型。     

1例水牛伊氏锥虫病的误诊分析

伊氏锥虫病是由锥虫科锥虫属的伊氏锥虫寄生于动物血液中的血细胞而引起的疾病。主要感染马属动物、牛和骆驼,其它动物如猪、犬、猫及某些野生动物亦可感染。锥虫在动物体内寄生,有的呈急性经过,而寄生于水牛体内大多是慢性经过,发病症状不明显,给诊断带来一定困难。     

伊氏锥虫体外培养株的建立及其HGPRT活性测定

用带虫培养法和带虫传代法建立了伊氏锥虫体外培养株，无论有、无饲养细胞，虫体均能快速增殖。培养７０ｄ以上，虫体仍保持原有生物学特性，对小鼠有感染性，活力旺盛，在体外能连续培养传代。虫数最高达２．４８×１０６／ｍＬ，群体增倍时间为８．８６～１０．８ｈ。液氮保存、复苏后的虫体可在饲养细胞上立即增殖。培养中发现由巨噬细胞转化的巨核母细胞对虫体生长有促进作用，经胰酶消化能与虫体一道连续传代。通过ＨＡＴ选择性培养液测定，伊氏锥虫对氨基喋呤不敏感，试验组虫体与对照一样生长良好，证明伊氏锥虫具有次黄嘌呤鸟嘌呤磷酸核糖转化酶（ＨＧＰＲＴ）     

伊氏锥虫感染力及其毒力的比较试验

伊氏锥虫是家畜主要的致病锥虫。不但感染众多的宿主,而且地理分布也十分广泛.其感染力及毒力因地理和宿主条件的不同而表现出差异.宿主中以马、大和大小鼠等为高度易感动物,感染后往往发病急、死亡快,而牛、兔和豚鼠等动物则较差,其感染呈慢性经过.我们通过小鼠及豚鼠人工感染试验对伊氏锥虫云南株和广东株的感染力及其毒力进行了比较观察。     

抗不同伊氏锥虫株抗体的交叉免疫实验

以抗广西株伊氏锥虫和抗南京株伊氏锥虫免疫血清分别与广西株伊氏锥虫和南京株伊氏锥虫进行体外中和作用,然后接种小鼠。结果经株特异性免疫血清作用的锥虫大部分失去了对小鼠的感染力,而经非株特异性免疫血清作用的锥虫仍然可使小鼠发病死亡。说明两株伊氏锥虫间具有完全不同的抗原性。     

锥虫不同分离株克隆及其等电聚焦分析

将两个伊氏锥虫及一个马媾疫锥虫的不同分离株分别接种用球磷酰胺处理的小鼠，获得五个克隆，用等电聚焦比较其蛋白质差异。结果表明，三个分离株之间有明显区别；马媾疫锥虫显著不同于伊氏锥虫；分离株不同克隆间区别较小，其中广东水牛株两克隆间带型相同，安徽水牛两克隆间带型略有区别。证明伊氏锥虫克隆间变异较小，锥虫不同分离株间变异较大，马媾疫锥虫与伊氏锥虫之间变异最大。     

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