犬传染性喉气管炎病毒的分离及鉴定

用犬肾细胞 (MDCK)从疑似犬传染性喉气管炎病毒感染犬的急性期血清中分离到 1株病毒 ,经血凝试验、免疫电镜观察、中和试验、免疫荧光抗体试验、细胞培养特征观察和回归动物试验等鉴定 ,证明所分离的病毒为犬传染性喉气管炎病毒 ,命名为 BJ- JB- 3。     

Peripheral white blood cell counts throughout pregnancy in non-aborting Neospora caninum-seronegative and seropositive high-producing dairy cows in a Holstein Friesian herd

Pregnancy is characterized by transient changes in the maternal immune system, also evident at peripheral level. The present study analyzes the kinetics and possible factors affecting peripheral white blood cell populations throughout pregnancy in a herd of high-producing dairy cows chronically infected or not with Neospora caninum. We examined 54 pregnant parous cows: 29 Neospora-seronegative and 25 Neospora-seropositive cows. Blood samples were collected on Days 90, 120, 150, 180 and 210 of gestation. General Linear Model (GLM) repeated measures analysis of variance showed that the interaction Neospora-seropositivity × parity significantly affected total leukocyte, neutrophil and monocyte counts with lower levels of total leukocytes, lower neutrophil and higher monocyte counts recorded in primiparous Neospora-seropositive cows. In addition, N. caninum-seropositive cows had significantly increased monocyte counts on Day 180 of gestation compared to seronegative ones. Other factors significantly associated with changes in total and/or differential leukocyte profiles were period of pregnancy, season, twin pregnancy and milk production. In conclusion, a parity-associated effect of chronic N. caninum infection was observed on peripheral blood cell profiles in dairy cattle during gestation.     

细胞永生化的研究进展

永生细胞系具有无限增殖能力,其自我更新能力、增殖分化模式、基因表达调控以及癌症等疾病研究一直以来也是分子细胞生物学领域的研究热点与难点.细胞永生化是指细胞在体外培养的时候,由于自身基因改变或者外界因素刺激,例如细胞周期检查点通路受损、端粒酶的再次激活上调、原癌基因激活等影响,使细胞分裂加快,并突破了自我衰老与凋亡机制,...     

应用兔肾原代细胞培养 兔粘液瘤病毒的研究

试用兔肾原代细胞传代；增殖兔粘液瘤病毒，呈现典型ＣＰＥ。粘液瘤病毒ＳＧ３３株在兔肾细胞上连续传３代之后，就不产生ＣＰＥ，在鸡胚上传３代再回归兔肾原代细胞，又呈现ＣＰＥ。ＳＧ＿（３３）在鸡胚上不能产生明显痘斑。维持液ｐＨ值影响ＳＧ＿（３３）在兔肾原代细胞上形成ＣＰＥ。     

Acute onset of pulmonary necrotising arteritis in a dog with a left-to-right patent ductus arteriosus

A 12-week-old, clinically normal Chihuahua was referred for investigation for a continuous heart murmur. Cardiac evaluation revealed an anatomically and haemodynamically typical left-to-right shunting patent ductus arteriosus. The continuous wave Doppler measurement of peak ductal jet velocity of 5.6 m/s was suggestive of a normal pulmonary to systemic arterial pressure ratio. The dog returned 16 days later with right heart failure and severe pulmonary hypertension. Marked reduction in left-to-right shunting was demonstrated and the ductal jet velocity had decreased to 2.5 m/s. Immediate ductus ligation, oxygen therapy before and after the operation, and administration of hydralazine failed to reduce pulmonary hypertension, and the dog was euthanased. Histopathological examination of the lung showed pulmonary necrotising arteritis with acute and chronic arterial lesions. Chronic pulmonary vascular changes related to high flow have been associated with altered nitric oxide and endothelin responses. These changes may be responsible for the acute onset of pulmonary hypertension due to relatively minor vascular insults in some human and veterinary patients with left-to-right shunts. The potential for acute progression supports the recommendations for early ductus ligation and the prognostic importance of detecting pulmonary hypertension presurgically in patent ductus arteriosus patients.     

Relative Flow-Time Relationships in Single Breaths Recorded After Treadmill Exercise in Thoroughbred Horses

Analysis of individual breaths after exercise has potential for pulmonary function testing. The aims of this study were to investigate the dependence of measurements of pulmonary function in single breaths on time postexercise and tidal volume (V_T) after treadmill exercise. Five Thoroughbred horses without evidence of airway disease were used. Horses had been previously acclimated to treadmill exercise and to wearing a face mask. A Quadflow spirometer recorded airflow rates continuously during 90 seconds after intense treadmill exercise to fatigue. Indices of function were based on ratios of times within each breath and analyses of the shape of relative flow–time curves within inspiration and expiration. Restricted maximum likelihood, general linear regression, repeated-measures one-way analysis of variance (ANOVA), and two sample t-tests were used, with statistical significance at P < .05. Time postexercise had no effect on several ratios based on time for inspiration (T_I) and expiration (T_E), and times to peak flows (T_I/T_T, T_E/T_T, T_E/T_I, Tpef [peak expiratory flow]/T_E, and Tpif [peak inspiratory flow]/T_I). Many variables were significantly dependent on V_T. Occasional big respiratory cycles with V_T more than 10% greater than in the previous breath had significantly different means for relative flow (Rf)/(T_E/T_I), epz_50% (50% of the time from Tpef to end of expiration), epz_75% (75% of the time from Tpef to end of expiration), and ipz_75% (75% of the time from Tpif to end of inspiration). Predicted means for these variables differed by 10–20%. This study establishes guidelines for the selection of breaths after exercise, and describes a new approach to measurement of relative flow and time relationships. It was concluded that several time-based ratios have potential for measuring pulmonary function. However, care is needed when selecting breaths for calculation of most of the new relative flow–time variables.     

Characterization of Interstitial Cells of Cajal in Bowel of Cattle (Bos taurus)

Interstitial cells of Cajal (ICC) have been described in the gastrointestinal tract of different mammals including humans, horses, pigs, rats, dogs, mice and guinea-pigs. In the present study, ICC were identified in the jejunum of Bos taurus using polyclonal anti-c-Kit antibodies in immunohistochemical assays. Vimentin and desmin intermediate filaments were also determined using monoclonal antibodies. ICC were found in the tunica muscularis either in a palisade distribution pattern between the outer longitudinal and the inner circular layers (ICC-MP) or freely distributed in clusters in the longitudinal layer (ICC-LM). Morphometric studies determined that ICC have a fusiform shape presenting cytoplasmic prolongations. ICC were positive to c-Kit and vimentin antigens but negative to desmin. We have observed and described for the first time the presence of ICC in a ruminant. As observed in the aforementioned mammals, bovine ICC were associated with the myenteric plexus. Nevertheless, the presence of widespread ICC in the longitudinal muscular layer of the jejunum differs from previously described studies of other mammals.     

Immunomodulatory effects of β-glucans on porcine alveolar macrophages and bone marrow haematopoietic cell-derived dendritic cells

The immunopharmacological activities of β-glucans with a backbone of β-1,3/β-1,6-linkages associated with anti-tumor, anti-viral, bacterial and fungal infections have been well documented. Dectin-1, a specific pattern recognition receptor for β-1,3/β-1,6-glucans, is expressed mainly on phagocytes, especially macrophages and dendritic cells (DCs). In this study, the encoding nucleotide for the carbohydrate-recognition domain (CRD) of porcine dectin-1 was sequenced for the first time, and the immunomodulatory functions of a synthetic particulate β-glucan (p-β-glucan) were examined. Results showed that p-β-glucan significantly enhanced cell activity and phagocytosis in porcine alveolar macrophages (AMs), immature DCs (imDCs) and mature DCs (mDCs), in a similar way to zymosan. Zymosan enhanced dectin-1/TLR2/TLR4 expression and TNF-α/IL-10 production in all of three types of cell, whereas p-β-glucan increased dectin-1/TLR4 and TNF-α/IL-12 production in AMs but inhibited IL-10 in mDCs. These results indicate that the complex collaborating interactions between dectin-1 and TLRs in the recognition of β-1,3/β-1,6-glucans with different structural features may direct different cellular responses.     

piggyBac转座子介导的家蚕细胞转基因研究初探

为探讨稳定转化家蚕细胞表达外源基因的新方法,以家蚕核型多角体病毒(BmNPV)极早期蛋白基因(ie-1)启动子元件驱动新霉素抗性基因(neor),并克隆至具有绿色荧光蛋白基因(gfp)标记的昆虫转座子载体piggyBac中,构建转基因载体pigA3-IE-Neo。以该载体转染家蚕BmN细胞,用终浓度800μg/mL的遗传霉素(geneticin,G418)筛选3个月,获得了稳定转化的细胞,呈现绿色荧光的细胞数达80%以上。通过PCR鉴定证实了细胞基因组DNA中neor基因和gfp基因的存在。     

哺乳动物成体干细胞的研究进展

干细胞具有自我更新能力,能够产生高度分化的功能细胞。干细胞按照发育阶段分为胚胎干细胞和成体干细胞。根据干细胞的发育潜能分为三类：全能干细胞、多能干细胞和单能干细胞。胚胎干细胞的发育等级较高,是全能干细胞,而成体干细胞的发育等级较低,是多能或单能干细胞。一般认为成年组织或器官内的干细胞具有组织特异性,只能分化成特定的细胞或组织,然而,研究结果表明,组织特异性干细胞同样具有分化成其他细胞或组织的潜能,这为干细胞的应用开创了更广泛的空间。作者主要综述了干细胞的研究进展及几种成体干细胞的诱导分化。