.基于TaqMan探针的牛布氏杆菌实时荧光定量PCR的特异性鉴定

根据牛布氏杆菌BM28保守序列设计引物和探针,建立了一种快速鉴定牛布氏杆菌的TaqMan实时荧光定量PCR方法。以梯度稀释的含有目的扩增片段的重组质粒作为标准品,进行定量PCR反应。结果显示:5.0×105~5.0×101拷贝范围内定量PCR均有"S"型扩增曲线,检测灵敏度为50拷贝每微升。本研究建立的实时荧光定量PCR方法具有灵敏度高、特异性和重复性好、方便经济的特性,在牛布氏杆菌的检测与鉴定中具有良好的应用前景。     

基于TaqMan探针的虎制品实时荧光定量PCR的特异性鉴定

根据虎线粒体细胞色素b核苷酸保守序列设计引物和探针,建立了一种快速鉴定虎制品的TaqMan实时荧光定量PCR方法。以梯度稀释的含有目的扩增片段的重组质粒作为标准品,进行定量PCR反应。结果显示,5.0×10⁵~ 5.0×10¹拷贝/μL范围内定量PCR均有"S"型扩增曲线,检测灵敏度为50拷贝/μL。对豹、狮子、猫等7种非虎哺乳动物DNA样本的检测结果均为阴性。本研究建立的实时荧光定量PCR方法具有灵敏度高、特异性和重复性好、方便经济的特性,在虎制品的检测与鉴定中具有良好的应用前景。     

猪流感病毒实时荧光定量RT-PCR检测方法的建立

本研究选取猪流感病毒(swine influenza virus,SIV)的NP基因序列设计引物和探针,建立了检测SIV的TaqMan实时荧光定量PCR方法。以梯度稀释的含有SIV目的扩增片段的质粒作为标准品,进行定量PCR反应以确定检测灵敏度。2.0×10⁸至2.0×10²拷贝/μL 7个数量级的范围内定量PCR有"S"型扩增曲线,检测灵敏度为20个拷贝/μL。根据病毒拷贝数与Ct值的关系绘制了标准曲线。该方法具有特异性,对猪瘟病毒、伪狂犬病病毒、口蹄疫病毒和猪繁殖与呼吸综合征病毒核酸都没有扩增反应。本研究建立的实时定量PCR方法,灵敏度高、特异性好,可以进行定量分析,在猪流感的快速检测上具有重要意义。     

实时荧光定量RT-PCR检测禽白血病病毒方法的建立与应用

建立了TaqMan实时荧光定量RT-PCR方法检测禽白血病病毒(ALV)。选取ALV病毒的LTR序列设计引物和探针,以梯度稀释的含有ALV目的扩增片段的质粒作为标准品,进行定量PCR反应以确定检测灵敏度。阳性标准品在3.0×102~3.0×107个拷贝共6个数量级的范围内,定量PCR反应有"S"型扩增曲线,检测灵敏度最低为30个拷贝。根据病毒拷贝数与定量反应Ct值的关系,绘制了标准曲线。该方法具有特异性,对新城疫病毒、禽流感病毒、传染性支气管炎病毒、传染性囊病病毒、鸡传染性贫血病毒和马立克病病毒核酸都没有扩增反应。实时定量PCR检测ALV的方法,灵敏度高,特异性好,可以进行定量分析,在禽病的快速检测上具有重要意义。     

实时荧光定量PCR检测鸡传染性贫血病毒方法的建立

建立了Taqman实时荧光定量PCR方法检测鸡传染性贫血病毒(CAV)。选取CAV病毒的序列设计引物和探针。以梯度稀释的含有CAV目的扩增片段的质粒作为标准品,进行定量PCR反应以确定检测灵敏度。2.0×105～2.0×102个拷贝,4个数量级的范围内定量PCR有"S"型扩增曲线,检测灵敏度为200个拷贝。根据病毒拷贝数与定量反应Ct值的关系,绘制了标准曲线。该方法具有特异性,对传染性支气管炎病毒、传染性法氏囊病毒、禽白血病病毒和马立克病毒核酸都没有扩增反应。采用实时荧光定量PCR方法检测试验感染鸡的肝脏、脾脏、肾脏、胸腺、法氏囊、泄殖腔棉拭子等样品,所有检测样品都有"S"型扩增曲线,且荧光信号值高。实时定量PCR检测CAV的方法,灵敏度高,特异性好,可以进行定量分析,在禽病的快速检测上具有重要意义。     

犬细环病毒SYBR GreenⅠ荧光定量PCR检测方法的建立

为建立犬细环病毒(TTCV)的快速检测方法,本研究根据GenBank中登录的TTCV ORF7基因设计合成一对特异性引物,并对反应条件和反应体系进行优化,建立了检测TTCV的SYBR Green I荧光定量PCR方法。结果显示:建立的荧光定量PCR方法 Ct值与标准品模板在5.82×10~9拷贝/μL~5.82×10~3拷贝/μL范围内呈良好的线性关系。该检测方法仅对TTCV检测为阳性,而对狂犬病病毒、犬冠状病毒、犬细小病毒、犬瘟热病毒和犬副流感病毒均无特异扩增;该检测方法灵敏度可达5.82×103拷贝/μL。对27份犬血清样品检测结果显示,建立的荧光定量PCR阳性检测率为11.11%,而普通PCR方法检测阳性率为3.7%。本实验建立了TTCV SYBR Green Ⅰ荧光定量PCR检测方法,对TTCV诊断及致病机制的研究提供了高通量的定量检测方法。     

鸡减蛋综合征病毒Hexon基因SYBR GreenⅠ实时荧光定量PCR检测方法的建立

用PCR方法扩增出鸡减蛋综合征病毒（EDSV）Hexon基因保守片段,经琼脂糖凝胶电泳及序列测定分析扩增产物的特异性。以构建的阳性重组质粒作为标准品,建立SYBR GreenⅠ实时荧光定量PCR反应的扩增曲线和溶解曲线,并绘制标准曲线。结果表明,建立的EDSV荧光定量PCR标准曲线Ct值与1×10^1～1×10^6拷贝/μL的基因拷贝数呈现良好线性关系,灵敏度可达10拷贝,且特异性及重复性良好;说明本试验建立的SYBR GreenⅠ实时荧光定量PCR检测方法可用于EDSV的诊断及病原的定量分析。     

兔出血症病毒SYBR Green Ⅰ荧光定量PCR检测方法的建立

为了建立兔出血症病毒(RHDV)快速、敏感的检测方法。本研究利用RT-PCR技术扩增出RHDVVP60基因中201bp的保守序列,并克隆到p MD18-T载体中作为标准品制作标准曲线,建立了RHDV的SYBR Green Ⅰ荧光定量PCR检测方法。该方法检测灵敏度可达6×101拷贝,与兔水疱性口炎病毒和轮状病毒均不发生交叉反应,具有良好的特异性和重复性。结果表明,建立的实时荧光定量PCR具有特异、敏感、快速、定量、重复性好等优点,可用于临床RHDV的检测。     

鸭瘟病毒SYBR Green I荧光定量PCR检测方法的建立

为建立鸭瘟病毒（DPV）快速、敏感的检测方法,本研究利用PCR技术扩增出DPV UL30基因中510bp的保守序列,并克隆到p MD18-T载体中作为标准品制作标准曲线,建立了DPV的SYBR Green I荧光定量PCR检测方法。该方法检测灵敏度可达5×101拷贝,与鸭细小病毒、鸭圆环病毒、小鹅瘟病毒、鸭肝炎病毒、鸭H9亚型流感病毒和鸭副粘病毒均不发生交叉反应,具有良好的特异性和重复性。结果表明,建立的实时荧光定量PCR具有特异、敏感、快速、定量、重复性好等优点,可用于临床DPV的检测。     

猪繁殖与呼吸综合征病毒SYBR GreenⅠ实时荧光定量PCR检测方法的建立

为建立猪繁殖与呼吸综合征病毒(PRRSV)SYBR GreenⅠ实时荧光定量PCR检测方法,采用RT-PCR扩增PRRSV N基因266bp片段,并克隆到pMD18-T载体中,以纯化的重组质粒为模板进行荧光定量PCR扩增,建立了PRRSV荧光定量PCR检测方法,该方法检测灵敏度可达1.3×101拷贝/μL,与猪瘟病毒(CSFV)、猪传染性胃肠炎病毒(TGEV)、猪流行性腹泻病毒(PEDV)和猪日本脑炎病毒(JEV)均不发生交叉反应,具有很好的特异性和重复性。结果表明,建立的PRRSV实时荧光定量PCR具有特异、敏感、快速、定量、重复性好等优点,可用于临床猪繁殖与呼吸综合征病毒病(PRRS)的诊断。     

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