猪细小病毒和猪圆环病毒2型二重液相芯片检测方法的建立

作者拟建立检测猪细小病毒(PPV)和猪圆环病毒2型(PCV2)的二重液相芯片(xMAP)检测方法,以满足出入境检疫和临床高通量检测的要求.依据GenBank中PPV结构蛋白VP2基因及PCV2全基因序列,设计PPV和PCV2特异性探针、引物及探针互补序列,将探针与磁性微球偶联,对下游引物和探针互补序列标记生物素,采用不对称性二重PCR扩增靶序列,将PCR产物与偶联好的探针进行杂交,用液相芯片仪进行检测.通过对检测条件优化,建立检测PPV、PCV2两种病毒的二重液相芯片技术,并对临床样本进行检测.建立的PPV和PCV2二重液相芯片检测方法,特异性良好,该方法对PPV和PCV2基因拷贝数检测下限分别为1.53×10 4、2.58×102;对56份临床样品检测表明,该方法与单项PCR检测结果符合率为100％.成功建立了PPV、PCV2二重xMAP检测方法,该检测技术可用于出入境检疫和兽医临床检验.     

多重PCR结合基因芯片技术检测5种猪繁殖障碍性病毒病方法的研究

为建立运用多重PCR和基因芯片技术同时检测5种猪繁殖障碍性病毒病的方法。本研究根据GenBank中登录的猪瘟病毒(CSFV)、猪细小病毒(PPV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪日本乙型脑炎病毒(JEV)及猪圆环病毒2型(PCV2)的基因序列设计特异性引物与探针,制备相应的寡核苷酸芯片,检测了5种猪繁殖障碍性疾病病毒的标准毒株,并对16份临床样品进行检测。通过多重PCR扩增出带有荧光标记的5种病毒的特异性基因片段,并与固定有特异性探针的基因芯片杂交。结果显示,本研究建立的多重PCR结合基因芯片检测方法特异性强、稳定性好,灵敏度可达10~2拷贝/μL。16份临床样品检测结果显示阳性率达87.5%(14/16)。以上结果表明该方法特异性好、灵敏度高,可高效检测以上5种病毒,为其临床诊断及流行病学调查提供了有效的检测方法。     

多重PCR结合基因芯片技术检测5种猪繁殖障碍性病毒病方法的研究

为建立运用多重PCR和基因芯片技术同时检测5种猪繁殖障碍性病毒病的方法。本研究根据GenBank中登录的猪瘟病毒(CSFV)、猪细小病毒(PPV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪日本乙型脑炎病毒(JEV)及猪圆环病毒2型(PCV2)的基因序列设计特异性引物与探针,制备相应的寡核苷酸芯片,检测了5种猪繁殖障碍性疾病病毒的标准毒株,并对16份临床样品进行检测。通过多重PCR扩增出带有荧光标记的5种病毒的特异性基因片段,并与固定有特异性探针的基因芯片杂交。结果显示,本研究建立的多重PCR结合基因芯片检测方法特异性强、稳定性好,灵敏度可达10~2拷贝/μL。16份临床样品检测结果显示阳性率达87.5%(14/16)。以上结果表明该方法特异性好、灵敏度高,可高效检测以上5种病毒,为其临床诊断及流行病学调查提供了有效的检测方法。     

猪瘟病毒和猪圆环病毒2型二重荧光LAMP检测方法的建立

建立二重荧光LAMP方法,检测猪瘟病毒(CSFV)和猪圆环病毒2型(PCV2)。根据CSFV E2基因和PCV2 ORF2基因序列保守区域,分别设计并合成了2组针对CSFV和PCV2序列的特异性引物和2条标记不同的荧光基团探针,在CSFV探针序列5′端标记FAM荧光基团,3′端标记BHQ1淬灭基团,PCV2探针序列5′端标记CY5.5荧光基团,3′端标记BHQ2淬灭基团。以设计合成的引物、探针以及LAMP反应试剂建立二重荧光LAMP检测方法区分CSFV和PCV2,对该方法中的反应体系进行优化,并进行特异性、敏感性和干扰性测试以及临床样品验证测试。结果表明,建立的方法可鉴别CSFV和PCV2,特异性试验显示,该方法只检测出CSFV或PCV2,且与参试的对照病毒无交叉反应,特异性好。该方法最低检测CSFV或PCV2为100拷贝/μL,敏感性好。临床样品的检测结果与荧光定量PCR检测结果一致。建立的CSFV和PCV2二重荧光LAMP检测方法具有良好的特异性和敏感性,可适用于CSFV和PCV2的鉴别检测。     

猪主要繁殖障碍疾病病原的多重实时定量PCR快速检测

本研究旨在建立多重Real-time PCR方法检测猪繁殖与呼吸综合征病毒(PRRSV)、猪圆环病毒2型(PCV2)、猪伪狂犬病毒(PRV)和猪细小病毒(PPV).根据GenBank数据库中PRRSV、PCV2、PRV、和PPV的核苷酸序列设计特异性引物和探针,通过优化反应条件,检测系列稀释的纯化阳性质粒,建立检测PRRSV、PCV2、PRV和PPV的单项和多重Real-time PCR方法.灵敏度和特异性试验结果表明,无论是单项和多重Real-time PCR检测,该方法都具有高度特异性,与其它病原检测无明显交叉反应;对4种病毒的最低检测量为＜101拷贝或1 TCID50,检测灵敏度比常规PCR高100倍.对40份临床样本进行检测,多重Real-time PCR检测结果和单项Real-time PCR检测结果完全一致.建立的同时检测PRRSV、PCV2、PRV和PPV的多重Real-time PCR方法具有快速、灵敏、特异、重复性好和能对样品进行定量检测等优点.     

检测猪繁殖与呼吸综合征病毒和猪圆环病毒的二重荧光LAMP方法的建立

建立一种二重荧光LAMP的检测猪繁殖与呼吸综合征病毒(PRRSV)和猪圆环病毒(PCV)的快速诊断技术。根据已发表的PRRSV NSP2基因和PCV2 ORF2基因序列保守区域,分别设计并合成了两组针对PRRSV和PCV2序列的特异性引物和两条探针,两条探针分别标记不同的荧光基团,PRRSV-Probe 5’端标记FAM荧光基团,3’端标记BHQ1淬灭基团,PCV-Probe 5’端标记CY5.5荧光基团,3’端标记BHQ2淬灭基团。对组成反应体系中的引物、探针以及反应试剂进行优化,建立了二重荧光LAMP检测PRRSV和PCV2方法。对建立的方法进行特异性和敏感性测试,并用模拟混合样品和临床样品进行检测验证。结果显示,本研究建立的方法可以鉴别区分PRRSV和PCV2,特异性试验表明该方法只检测出PRRSV或PCV2,且与参试的对照病毒无交叉反应,特异性好。敏感性测试表明该方法最低检测PRRSV或PCV为100拷贝,敏感性好。对临床样品的检测,结果与荧光定量PCR方法检测结果一致。本研究建立的PRRSV和PCV2二重荧光LAMP检测方法,具有良好的特异性和敏感性,可用于临床样品中检测PRRSV和PCV2。     

猪圆环病毒2型TaqMan实时荧光定量PCR检测方法的建立

本研究以猪圆环病毒2型(PCV2)核衣壳蛋白ORF2基因为目的基因,设计合成特异性引物和探针。PCR扩增得到目的基因,并克隆到pMD18-T载体,筛选得到标准阳性质粒。通过对荧光定量PCR反应条件的优化,建立了PCV2的TaqMan实时荧光定量PCR检测方法。试验结果表明,该方法特异性强,对猪伪狂犬病病毒(PRV)、猪繁殖与呼吸综合征病毒(PRRSV)、猪瘟病毒(CSFV)等猪常见病原的检测结果均为阴性;与普通PCR方法相比,其敏感性高出100倍,可达100拷贝/μL;对临床样品的检测证明,该方法可有效检测出淋巴结、肺脏等组织中的PCV2。     

猪圆环病毒3型荧光定量PCR检测方法的建立及其在猪体中的组织分布研究

为了解猪圆环病毒3型(PCV3)在猪体中的组织分布情况,针对PCV3 Cap蛋白基因设计筛选出一对特异性引物和探针,通过对荧光PCR引物、探针浓度进行优化,建立了基于TaqMan探针实时荧光定量PCR技术的PCV3检测方法,并应用该方法对人工感染PCV3猪的多种组织器官进行病毒含量检测。结果显示,建立的PCV3实时荧光定量PCR检测方法特异性较好且灵敏度高,可检测低至1 copy/μL的PCV3病毒核酸量,而对其他几种常见猪病毒病原的检测结果均为阴性。PCV3主要存在于肺脏、淋巴结,在扁桃体和脾脏中有少量存在。试验表明,所建立的荧光定量PCR检测方法可用于PCV3的快速定量检测,对PCV3在猪体中的组织分布情况的研究为进一步揭示PCV3的组织嗜性和致病机理提供理论依据。     

猪圆环病毒2型和猪细小病毒双重PCR检测方法的建立及应用

根椐Gen Bank中登录的猪圆环病毒2型(PCV2)和猪细小病毒(PPV)核苷酸序列,分别设计2对引物,在建立各病毒单项PCR技术的基础上,优化双重PCR反应条件,建立了2种病毒的双重PCR检测方法,用这2对引物对同一样品中的PCV2和PPV核酸模板进行双重PCR扩增,结果可同时扩增PCV2的245 bp、PPV的475 bp的特异性片段,而对其他4种病原的PCR扩增结果均为阴性。敏感性测定结果表明,该双重PCR技术能检出1 pg的PCV2和1 pg的PPV模板。用105份临床病料对本研究双重PCR技术和单项PCR技术进行对比验证,结果显示,两者的总符合率为100%。表明建立的双重PCR检测方法具有特异、快速、准确的特点,可用于对这两种病毒的同时检测和鉴别诊断。     

用地高辛标记的核酸探针检测猪伪狂犬病毒野毒感染的研究

利用PCR技术从带有伪狂犬病毒（PRV）gE基因的重组质粒pMD18-T-gE中扩增回收约304bp大小的片段,并制备出地高辛标记的gE基因核酸探针。特异性检测结果表明,该探针能与重组质粒DNA发生特异性杂交,而与对照的PRVBartha-k61株疫苗毒DNA、猪细小病毒（PPV）DNA、猪圆环病毒（PCV）DNA、猪繁殖与呼吸综合征病毒（PRRsV）cDNA、猪瘟病毒（CSFV）cDNA的杂交反应均为阴性;敏感性检测结果表明,该探针对PRV野毒的最低检出量为4pg。应用该探针对11份繁殖障碍病料进行了杂交检测,共检出4份阳性病料,该结果与PCR检测结果一致,表明该核酸探针可用于猪伪狂犬病野毒感染的临床诊断。     

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.     

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