地高辛标记大肠杆菌1型菌毛结构基因核酸探针对鸡大肠杆菌分离株？…

将ＰＣＲ扩增的鸡大肠杆菌１型菌毛蛋白结构基因（ｐｉｌＡ）用地高辛标记成核酸探针与分属２８个血清型的５０个鸡大肠杆菌分离株进行斑点杂交，阳性率达８４％，用甘露糖敏血凝试验（ＭＳＨＡ）检测阳性率为７２％，表明核酸杂交比ＭＳＨＡ法更敏感。     

F1菌毛抗原在致病性大肠杆菌实验感染鸡体内的定殖和表述

导致鸡发生败血症的大肠杆菌一般具有Ｆ１（Ｉ型）菌毛（由Ｐｉｌ同源基因群编码）和／或Ｐ菌毛（由ｐａｐ同源基因群编码），这些菌毛通常被认为与感染和定殖有关。本实验以３株致病大肠杆菌（Ｅ．ｃｏｌｉ）Ｏ１（Ｐｉｌ＾＋／ｐａｐ＾＋）、Ｏ２（ｐｉｌ＾＋／ｐａｐ）和Ｏ７８（ｐｉｌ＾＋／ｐａｐ＾＋）通过气管内注射１．５周龄鸡，旨在探讨由不同毒力因子引起传染的动力学变化及其菌毛在体内的表述，感染后３～１４４小时剖检     

地高辛标记P菌毛基因检测探针鸡大肠杆菌

用地高辛标记鸡大肠杆菌Ｐ型菌毛结构基因（ｐａｐＡ）制成核酸探针,作斑点杂交试验,检测２８个血清型鸡大肠杆菌５０个菌株与该探针的同源性。结果表明有５个菌株被检测为阳性,阳性率为１０％。     

鸡大肠埃希氏菌菌毛分类方法的研究

用Ｄ－甘露糖敏感血凝特性（ＭＳＨＡ／ＭＲＨＡ）及聚合酶链反应（ＰＣＲ）扩增２种方法对鸡大肠埃希氏茵茵毛进行分类,证明ＭＳＨＡ／ＭＲＨＡ具有方便,快速及较可靠的特点,但不太敏感;ＰＣＲ则具有快速速、敏感、准确、可靠的优点,用ＰＣＲ对鸡大肠埃希氏茵进行分类是一种十分有效的新方法。     

禽病原性大肠杆菌I型菌毛单克隆抗体的研制及其对分离株的检测

从禽病原性大肠杆菌分离株ＴＫ３（Ｏ１）提取Ｉ型菌毛免疫ＢＡＩＢ／ｃ小鼠,取其脾细胞与小鼠骨髓瘤细胞融合,获得４株能稳定分泌针对Ｉ型菌毛的单克隆抗体杂交瘤细胞株,分别命名为ａＢ６、ｂＧ５、ｃＦ３和ｃＧ３。单克隆阻断甘露糖敏血凝试验,免疫胶体金和Ｗｅｓｔｅｒｎ ｂｌｏｔ试验证明,单抗是Ｉ型菌毛特异的。这些单抗培养上清及腹水的ＥＬＩＳＡ效价为分别为１０＾－２～１０＾－３和１０＾－５～１０＾－６;腹水的平     

抗A型产气荚膜梭菌α毒素单链抗体1A8的基因克隆及序列测定

应用ＲＴ－ＰＣＲ技术,从分泌具有中和活性的抗Ａ型产气荚膜梭菌α毒素单克隆抗体（ＭcＡb）的杂交瘤细胞１Ａ８中,扩增出抗体ＶＨ和ＶＬ基因,用linker（Ｇ１y４Ｓir３） ３基因,将ＶＨ和ＶＬ基因连接成ＳeＦＶ基因,并将其克隆至pＧＥＭ－Ｔ载体中。经核甘酸序列分析证实,ＶＨ和ＶＬ基因及linker基因拼接正确,基因全长７２９bp,经计算机分析,ＶＨ和ＶＬ基因均为新发现的基因序列,符合功能性重排的鼠抗体可变区基因特征。     

抗A型产气荚膜梭菌α毒素单克隆抗体杂交瘤细胞系的建立与中和效应

用提取的 Ａ 型产气荚膜梭菌 α毒素包涵体免疫 Ｂ Ａ Ｌ Ｂ／ｃ 小鼠后， 取小鼠脾细胞与 Ｓ Ｐ２／０ 骨髓瘤细胞进行融合和克隆化，经间接 Ｅ Ｌ Ｉ Ｓ Ａ 筛选，共获得 １ Ａ８、１ Ｃ３、１ Ｄ５、１ Ｄ８、１ Ｆ１、１ Ｈ１ 和 ２ Ｅ３ ７ 株稳定分泌单克隆抗体（ Ｍ ｃ Ａｂ）的杂交瘤细胞株。经鉴定，７ 株 Ｍ ｃ Ａｂ 的 Ｉｇ 亚类有 Ｉｇ Ｇ１（１ Ｄ８）、 Ｉｇ Ｇ３（１ Ａ８、１ Ｃ３ 和 ２ Ｅ３）和 Ｉｇ Ｍ（１ Ｄ５、１ Ｆ１ 和 １ Ｈ１）。细胞培养上清和腹水抗体效价分别为 １∶５１２～１∶１ ０２４ 和 １∶１０６ ～１∶１０８ 。尤为重要的是，２ Ｅ３ 杂交瘤细胞株分泌的 Ｍ ｃ Ａｂ 不仅能够中和 α毒素的磷脂酶 Ｃ活性和溶血活性，而且能够对致死性腹腔感染小鼠产生良好的被动保护作用。     

鸡大肠埃希氏菌菌毛表达、血凝谱及粘附特性研究

对６株具有不同致病性的鸡大肠埃希氏菌分离株体外菌毛的表达、对１３种不同红细胞血凝谱及血凝方式、对鸡胚成纤维细胞（ＣＥＦ）及在体内外对１日龄鸡气管组织的粘附特性进行了研究,结果表明,具有致病性的菌株,在体外适宜的条件下,能表达菌毛,非致病性菌株不表达。不同菌株的血凝谱及血凝方式具有差异,除中等致病性菌株ＭＧ３０e对大鼠红 细胞（ＲＢＣＦ）的凝集不能被Ｄ－甘露糖抑制,表现为抗甘露糖型血凝（ＭＲＨＡ）外,     

PCR法检测血清I型马立克氏病病毒及其敏感性试验的研究

以人工合成的针对血清Ｉ号马立克氏病病毒（ＭＤＶ１）Ａ抗原基因（ｇＡ）部分序列的两端寡聚核苷酸为聚合酶链反应（ＰＣＲ）的引物，分别对马立克氏病病毒血清Ｉ型（京－１株，ＭＤ１１／７５Ｃ株）；２型（ＳＢ－１株）；３型（火鸡疱疹病毒的ＦＣ１２６株）毒株和ＧＡ株ＢａｍＨＩ Ｂ片段的ＰＡＣＹ１８４克隆重组质粒ＤＮＡ进行基因扩增反应及其敏感性试验。结果表明，该引物不仅对ＭＤＶ１具有较强的特异性，而且由此引物引导     

HIV—2gag基因在重组痘苗病毒中的表达

以痘苗病毒ＨＡ基因为侧翼，将ＨＩＶ－２ｇａｇ基因部分序列（简称Ｇ１）和全部序列（简称Ｇ２）分别插入牛痘病毒Ａ型包涵体（ＡＴＩ）和串联１０个（与ＨＡ基因反向）或１６个（与ＨＡ基因同向）痘苗病毒Ｐ７．５组成的复合型启动子下游，构建了４个重组痘苗病毒表达载体质粒。经脂质体转染、鸡红细胞吸附试验筛选和免疫荧光鉴定，获得４株能稳定表达目的蛋白的重组痘苗病毒。实验结果表明，以ＨＡ基因为侧翼构建重组病毒的重组率约为０．１％，阳性重组率为２５％～１００％。实验中还发现，以ＨＡ基因为侧翼的重组痘苗病毒能够引起细胞融合，其可作为筛选重组痘苗病毒的另一种标志。Ｗｅｓｔｅｒｎｂｌｏｔ结果表明，表达的Ｇａｇ蛋白能被ＨＩＶ－２血清中的特异性抗体所识别，并能诱导小鼠产生抗ＨＩＶ－２Ｇａｇ抗体。     

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