地高辛标记空肠弯曲菌DNA探针的研究

应用地高辛标记核酸技术将地高辛结合到空肠弯曲菌染色体ＤＮＡ上,制备了地高辛标记的ＤＮＡ探针。地高辛标记的空肠弯曲菌ＤＮＡ探针仅与空肠弯曲菌ＣＪ１、ＣＪ２发生反应,而与大脾性杆菌、鼠沙门氏菌、金黄色葡萄球菌、副结核分枝杆功不发生反应,具有很高的特异性,其敏感性可检测出０．２２ｎｇ的样品ＤＮＡ,较光敏生物素（８ｎｇ）、＾３２Ｐ同位素（４ｎｇ）标记的核酸探针高。     

鸟类禽类性别决定的遗传控制及其调控

此文简要回顾了果蝇、鸟类、有袋目动物和真兽亚纲动物的性别系统。禽类多倍体、非整数倍体和雌雄嵌合体的材料表明，鸟类性别由Ｚ与常染色体比例决定，。限性性状可能同时受细胞自主和激素的双重控制。为确定鸟群的非整倍体，用一个与许多鸟群的Ｚ和Ｗ染色体体连锁的ＣＤＮＡ克隆筛选鹦鹉科鸟，发现５只带有非典型的了限制性带型。用腹腔镜检查了其中两只，发现是雌雄间体。这些初步观察的结果表明，Ｚ、Ｗ染色体的结构变化会导致性     

两个家系猪的DNA指纹图谱遗传分析

本文用人源小卫星探针３３．６和３３．１５获得了两个家系猪的ＤＮＡ指纹图谱。通过对Ｆ１和Ｆ２代家系分析，证实ＤＮＡ指纹图带以孟德尔方式遗传。在家系２（探针３３．６）的１个后代中发现了一条新突变带。文中还对这两个探针检测到的位点数进行了估测     

鸟类禽类性别决定的遗传控制及其调控

此文简要回顾了果蝇、鸟类、有袋目动物和真兽亚纲动物的性别决定系统。禽类多倍体、非整数倍体和雌雄嵌合体的材料表明，鸟类性别由Ｚ与常染色体比例决定。限性性状可能同时受细胞自主和激素的双重控制。为确定鸟群的非整倍体，用一个与许多鸟群的Ｚ和Ｗ染色体连锁的ｃＤＮＡ克隆筛选鹦鹉科鸟，发现５只带有非典型的限制性带型。用腹腔镜检查了其中两只，发现是雌雄间体。这些初步观察的结果表明Ｚ、Ｗ染色体的结构变化会导致性别的改变     

胚胎性别鉴定：现代技术评论及在畜牧生产商业化应用方面的潜力（上）

胚胎移植技术的发展为通过胚胎性别鉴定控制家畜后代性别开辟了新的途径。目前，鉴定的方法已发到５种；即：细胞遗传学分析；Ｘ－染色体关联酶活性的测定；胚胎发育速率的差异性分析；雄性特异性抗原的探测，以及Ｙ－染色体特异性ＤＮＡ探针。采用牛的Ｙ－染色体特异性ＤＮＡ序列的鉴定方法。可以从９０％以上的少于２细胞胚胎样品中鉴定胚胎性别达到９４％的准确率。因经济和技术原因，胚胎性别鉴定还未在常规胚胎移植中广泛应用。     

牛雄性特异性DNA片段的分子克隆

根据小牛胸腺ＤＮＡ复性动力学原理，采用改进的“删除富集法”，对Ｙ特异性ＤＮＡ片段进行富集。以ｐＵＣ１８为宿主菌，构建成富集有Ｙ特异性的部分Ｙ染色体文库。分别以牛雄性和雌性基因组ＤＮＡ为探针，对克隆子进行“差异筛选”，筛选到若干个雄性特异性信号。对其中１个克隆子进行分析鉴定，测得其插入片段大小约为１．４ｋｂ。将其标记成探针。命名为Ｐ－ｄ。分别与２０个公牛基因组ＤＮＡ样品和８个母牛基因组ＤＮＡ样品杂交，阳性信号符合率为８５％，阴性信号符合率为８７．５％。初步证明Ｐ－ｄ具有雄性特异性。研究表明，用本实验方法所克隆到的雄性特异性ＤＮＡ探针鉴别牛胚胎的性别是可能的。     

猪细小病毒分离,核酸探针研制及应用

采用分子克隆技术制备了ＰＰＶ－ＤＮＡ－Ｃ片段（ＰＰＶ－ＲＦ－ＤＮＡ,经Ｐｓｔ Ｉ／Ｈｉｎｄ Ⅲ的双酶切片段,称为Ｃ片段）及含Ｃ片段的ＰＵＣ１９重组质粒（ＰＵＰ）,利用地高辛标记,分别制备探针２和探针１。对猪细小病毒ＤＮＡ进行斑点杂交,两种探针均为阳性,而对照的猪瘟病毒、猪伪狂犬病毒、乙型脑炎病毒及ＰＫ－１５细胞的核酸均为阴性。并且后一种探针的敏感性高于前者,两种探针的ＤＮＡ检出限量分别为４０ｐｇ和     

应用核酸杂交技术检测畜禽衣原体病的研究

从纯化山羊流产衣原体颗粒提取ＤＮＡ，用ＤＮＡ限制性内切酶切割，进行酶切图谱分析，与文献报道的图谱对比，证实确系纯的衣原体ＤＮＡ制品。将衣原体ＤＮＡ用光敏生物素标记，制成核酸探针，用斑点杂交法检测衣原体核酸，灵敏度可达１０ｐｇ。又用重组克隆技术将衣原体ＤＮＡ片段克隆于大肠杆菌质粒载体上，筛选出衣原体特异的ＤＮＡ片段制成光生物素探针，可以同样有交效地检测衣原体核酸。用光生物素衣原体探针检测了山羊、绵羊、豚鼠、小白鼠、鸡胚等的衣原体感染病料，结果准确。与间接血凝法检测衣原体感染做了对比试验，证明核酸杂交法检测衣原体病更为灵敏和特异     

嗜水气单胞菌HEC毒素基因的克隆及酶谱分析

嗜水气单胞菌ＨＥＣ毒素是该菌重要的致病因子和保护性抗原。为了解其分子生物学特性，用ＳＤＳ－蛋白酶Ｋ法提取了嗜水气单胞菌Ｊ－１株的染色体，经ＥｃｏＲＩ酶切、琼脂糖凝胶电泳后作Ｓｏｕｔｈｅｒｎｂｌｏｔｔｉｎｇ，用ＤＩＧ标记的ＨＥＣ毒素探针检测，其５．０ｋｂ的酶切片段呈阳性。回收该片段，与ｐＵＣ１９相连，转化大肠杆菌ＪＭ１０９。提取Ｘ－ｇａｌ平板上白色菌落的质粒，经大小比较、ＥｃｏＲＩ酶切分析及ＤＩＧ标记ＨＥＣ毒素核酸探针斑点杂交鉴定，获得ｐＨＥＣ１１等含５．０ｋｂ目的ＤＮＡ片段的重组质粒。ｐＨＥＣ１１质粒经酶切、电泳，证实目的ＤＮＡ片段中含有ＢａｍＨＩ、ＳｍａⅠ、ＰｓｔⅠ及ＰｖｕⅡ等酶切位点，并绘制了其物理图谱。同时还构建了若干亚克隆，为研制嗜水气单胞菌基因工程苗提供了目的基因片段。     

地高辛标记C15A核酸探针检测牛巴贝斯虫

为了提高牛巴贝斯虫核酸探针的检测性能,制备了地高辛标记的牛巴贝斯虫Ｃ１５Ａ核酸探针。该探针检测牛巴贝斯虫ＤＮＡ的灵敏度为３２ｐｇ,检测探针ＤＮＡ的灵敏度为０．１ｐｇ;检测其他对照血液原虫（双芽巴贝斯虫、边缘无浆体、瑟氏泰勒虫、伊氏锥虫、卵圆巴贝斯虫）和牛血细胞的ＤＮＡ,均未出现非特异性反应。与光敏生物素标记的牛巴贝斯虫Ｃ１５Ａ核酸探针比较,光敏生物素标记探针能检出１０％带虫血１２．５μＬ,而地高辛标记探针能检出１０％带虫血０．０１５μＬ,且杂交背景浅,显色深。     

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.     

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.     

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.     

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