牛白血病病毒对牛免疫系统功能影响的研究进展

哺乳动物的免疫系统主要包括体液免疫和细胞免疫.但目前大多数学者认为B淋巴细胞是牛白血病病毒的靶细胞,BLV不但能引起B淋巴细胞持续性增生,同时也能引起B淋巴细胞持续性减少.本文主要对BLV感染对牛B淋巴细胞的影响进行了阐述,同时探讨了T淋巴细胞在BLV感染牛发生的变化.     

Activation of the Renin-Angiotensin System in Dogs With Asymptomatic and Mildly Symptomatic Mitral Valvular Insufficiency

The renin-angiotensin system has important pathophysiologic implications in the development of congestive heart failure. The activity of the renin-angiotensin system early in the course of heart disease and heart failure in dogs was evaluated by measuring the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in 18 Cavalier King Charles Spaniels with asymptomatic or mildly symptomatic mitral valvular insufficiency, and in 18 healthy Cavalier King Charles Spaniels. All dogs were unmedicated and had no other diseases. The PRA was high in the dogs with mitral valvular insufficiency (median 3.44 ng/mL/h, interquartile interval 2.59 to 8.66 ng/mL/h) compared with the controls (median 2.51 ng/mL/h, interquartile interval 1.44 to 3.58 ng/mL/h). The PAC was also higher in the dogs with mitral insufficiency (median 53 pg/mL, interquartile interval 33 to 138 pg/mL) than in the control group (median 27 pg/mL, interquartile interval 11.5 to 54 pg/mL). However, there was considerable overlap between the 2 groups in both PRA and PAC. It was concluded from these data that there is early activation of the renin-angiotensin system in some Cavalier King Charles Spaniels with mitral valvular insufficiency. Further prospective studies are needed to determine if early intervention with angiotensin-converting enzyme inhibitors will be valuable in this group of patients.     

牛消化系统疾病病因探讨

目前许多养牛企业只重视发展种群数量和产量,而忽视养殖过程中的疾病防治,由于细菌、病毒、寄生虫、饲养管理不科学或者其他人为因素等影响,牛消化系统疾病发病概率相对较高,引起牛死亡的案例较多,因此,笔者经多年临床生产实践总结,从多角度对牛消化系统疾病病因进行了探讨,为进一步防治本病提供科学参考。     

牛星状病毒、牛病毒性腹泻病毒1型、牛冠状病毒和牛轮状病毒四重实时荧光定量RT-PCR检测方法的建立

利用多重荧光定量RT-PCR （real-time RT-PCR）方法,提高对多病原检测的速度和灵敏度,促进对犊牛腹泻的快速诊断和及时治疗。分别在牛星状病毒（BAstV）ORF2基因,牛病毒性腹泻病毒1型（BVDV-1）5'端非编码区,牛冠状病毒（BCV）N pro基因和牛轮状病毒（BRV）VP6基因的保守基因序列设计、合成并试验筛选了四对有效的特异性引物和探针。进一步利用含4种病毒目的片段的重组质粒,对引物和探针的浓度以及反应条件进行了优化,建立了Real-time RT-PCR标准曲线,并对四重Real-time PCR方法的特异性、敏感性、重复性和各种临床样本的适用性进行了评价。结果显示：Real-time RT-PCR最适退火温度和时间分别为50.0℃和45 s,BAstV、BVDV-1、BCV和BRV的引物浓度分别为300、300、400和500 nmol·L^-1,探针浓度分别为250、150、100和300 nmol·L^-1。对BVDV-1、BCV和BRV的最低检测限均为10²copies·μL^-1,对BAstV的最低检测限为10³ copies·μL^-1,具有良好的特异性和重复性。该方法对临床采集的粪样的阳性检出率高于PCR方法。上述结果表明,建立的四重Real-time RT-PCR方法可以用于犊牛腹泻常见病原BAstV、BVDV-1、BCV和BRV的快速鉴别诊断。     

牛γ-干扰素在牛结核检测中的研究应用

γ-干扰素是细胞因子超家族中IFN家族的重要成员,具有广泛的生物学功能,其功能的多样性是通过诱导细胞表达多种蛋白质而实现的。作者对γ-干扰素的产生、诱导、临床试验、检测诊断及γ-干扰素的优点和其他用途的研究进展进行综述。     

Some Effects of a Low Sodium Diet High in Potassium on the Renin-Angiotensin System and Plasma Electrolyte Concentrations in Normal Dogs

Pedersen, H.D., J. Koch, A.L. Jensen, K. Poulsen, A. Flagstad: Some effects of a low sodium diet high in potassium on the renin-angiotensin system and plasma electolyte concentrations in normal dogs. Acta vet. scand. 1994, 35, 133-140. - Eight normal male Beagle dogs received 0.7 mmol Na⁺/kg/day for 5 weeks and 4.0 mmol Na⁺/kg/day in one 3 week control period preceding and another similar period following the low sodium period. The dogs received 6.8 mmol K⁺/kg/day throughout the study.The median plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were higher in the low sodium period than in the following control period (0.67 versus 0.28 ng/ml/h, p < 0.0001) and (204 versus 31 pg/ml, p < 0.0001). PRA and PAC quickly stabilized on a new steady level in response to altered intake of sodium chloride. The angiotensin-converting enzyme (ACE) activity was not changed by the altered intake of sodium chloride.The plasma concentrations of sodium and chloride were increased during the low sodium period. This could be due to an indirect effect of the high potassium intake of the dogs. Potassium leads to an increased secretion of aldosterone and thereby to an increased retention of sodium and chloride in the kidney. The possible implications of a high potassium content in a low sodium diet are discussed.     

牛早期胚胎性别鉴定PCR反应体系的优化研究

根据牛SRY基因序列设计合成2对巢式PCR引物作为性别鉴定引物，根据牛酪蛋白基因序列设计了一对引物作为内标引物建立了牛胚胎性别鉴定的PCR反应体系。同时对常规PCR和巢式PCR在牛早期胚胎性别鉴定中的实用性进行比较。15头公牛、13头母牛的DNA样品检测结果表明：使用巢式PCR公牛可以扩增出205bp的SRY基因片段和403bp的酪蛋白基因片段，母牛只能扩增出403bp的酪蛋白基因片段；而使用常规PCR时公牛扩增出255bp的SRY基因片段和403bp的酪蛋白基因片段，母牛只能扩增出403bp的酪蛋白基因片段，其性别鉴定结果和实际完全一致。由于巢式PCR只需10个细胞就可以在紫外透射分析仪下看到扩增结果，而常规PCR则需要20～30个细胞，所以胚胎性别鉴定时使用巢式PCR效果更好。试验采用巢式PCR鉴定了10个奶牛胚胎的性别，同时还对血清是否会对试验结果产生影响进行了研究。     

牛暂时热研究进展

牛暂时热是一种发生于热带与温带地区牛的急性、免疫病理性病毒病，包括蚊、蠓在内的多种昆虫参与了该病的传播。本文就BEFV的病原学、流行病学、传播、防制、研究进展及研究趋势做了综述。     

Infection of the Bovine Udder with Bovine Herpesvirus

Infectious bovine rhinotracheitis — infectious pustular vulvovaginitis (bovine herpesvirus) grown in tissue culture was used as inoculum in trials to infect the lactating bovine udder. Six experiments were undertaken in which one or more quarters were infused with 1 ml. of tissue culture fluids containing 10⁶ to 10⁷ tissue culture infectious doses (TCID) of virus. In four of the experiments the inoculated quarters showed marked evidence of infection in the form of acute inflammation, swelling, reduced milk secretion and profound changes in the physical appearance of the milk. In each case virus was recovered in high titres in the milk from about the second until the tenth to fifteenth days following exposure. Uninfected quarters remained normal in appearance and virus could not be recovered from the milk.

In three of the experiments it was shown that serum and milk antibodies appeared shortly after the disappearance of virus from the milk. One experiment involving two animals showed that about 1000 TCID of virus were required to produce infection. In one experiment a cow having a pre-inoculation serum titre for bovine herpesvirus proved resistant to infection.

The experiments indicate that the bovine udder is readily susceptible to bovine herpesvirus in non-immune animals, and that the virus produces an acute, limited infection leading to a temporary disfunction of the gland. It appears that natural invasion of the udder through the teat canal is not readily accomplished by the virus.

     

牛结核病的诊断研究进展

牛结核病是由结核分支杆菌引起的牛的一种慢性消耗性传染病,不仅严重危害养牛业的发展,也对人的身体健康造成威胁。做好牛结核病的诊断,是实现该病净化的一种重要手段和前提。本文从病原学、血清学、分子生物学等方面对该病的诊断进行了阐述。     

The Postnatal Development of the Bovine Leydig Cell Population

Contents: The postnatal development of the bovine Leydig cell population from week 4 to young adulthood (75–100 weeks) was examined with morphometric techniques using perfusion-fixed samples and histological, semithin and ultrathin sections. Leydig cell mass per testis increases from 0.15 g to 3.62g between weeks 4 and 16, from 3.64 g to 5.93 g between weeks 20 and 30 and from 7.28 g to 10.47 g between 1 year and 1 1/2 to 2 years. Relative Leydig cell volume per unit is largest in week 16 (17.1 %). Calculated number of Leydig cells per testis amounts to 0.42 ± 10⁹ in week 4 and 6.02 ± 10⁹ in the adult group. Leydig cell nuclear diameter in week 4 (5.6 ± 0.3 pm) is significantly smaller and in week 75–100 (7.4 ± 0.4 μm) significantly larger than in weeks 8 through 52. Irrespective of varying Leydig cell size, the relative content of eR (about 48%) and mitochondria (about 8%) fluctuates in narrow limits during the entire period. The individual Leydig cell of week 4 has less than 20%, of week 8 about 30%, of weeks 16 through 52 about 50% of the volume of a Leydig cell of young adult (75–100 weeks) animals .     

牛人工授精时应注意的一些事项

本文就牛人工受精从受体牛的发情鉴定到发情时间的掌控,冻精解冻装枪、输精以及输精部位等需要注意的一些事项进行了详细的阐述,得出牛人工授精过程中影响受胎率的一些因素,可大大提高受胎率,提高生产性能。