高强度聚焦超声联合乳化碘油损伤不切肋骨山羊肝脏组织的实验研究

目的探讨高强度聚焦超声（HIFU）损伤不切肋骨山羊肝脏组织的可行性。方法31只羊随机分成两组，实验组经静脉注入乳化碘油，用HIFU对肝脏进行辐照，比较坏死组织体积、能效因子、靶区灰度及组织病理检查。对照组以normal saline代替乳化碘油，余步骤同实验组。结果两组损伤组织均为凝固性坏死。实验组损伤率、靶区灰度阳性率分别为71．1％和26．8％，对照组分别为16.3％和4.1％（P〈0．05）。结论乳化碘油可增强HIFU的损伤效果，通过一定的手段实现在不切肋骨条件下对肝脏组织的HIFU损伤是可行的。     

不同山羊个体的精子结合和内化外源DNA能力的差异性研究

目的探讨不同山羊个体的精子结合和内化外源DNA能力差异性，以及精子内化能力对制备转基因山羊胚胎阳性率的影响。方法用地高辛标记与检测试剂盒检测12只山羊的精子分别结合、内化质粒DNApEGFP-N1的效率；体外受精实验检测胚胎阳性率与精子内化pEGFP-N1能力的关系。结果不同山羊个体的精子结合和内化pEGFP-N1的效率存在差异，内化效率最高为53．7％，最低为3．1％；3号公羊的精子体外转染外源基因后行体外受精，所得的2～8细胞胚胎表达外源基因pEGFP-N1的阳性率最高，7、8、10、11号公羊的精子体外转染外源基因后行体外受精，所得的2～8细胞胚胎均未表达GFP蛋白。结论不同山羊个体的精子自发结合、内化外源DNA的能力存在差异；不同山羊个体的精子体外转染外源基因后行体外受精，所得的2～8细胞胚胎表达外源基因的比例不同。     

提高精子转染外源DNA效率的山羊精液冷冻方法

目的筛选一种既提高精子转染外源DNA效率,又保持解冻后精子活力的山羊精液冷冻—解冻方法。方法应用正交设计L9(34),因素分别为稀释液种类、稀释比例、降温时间和解冻液,每个因素选择3个水平,检测和比较解冻后精子转染外源DNA效率和精子活力。结果所选冷冻—解冻各因素对精液转染效率影响不显著[F(8,18)=1.032,P=0.449];平衡时间对冷冻—解冻活力影响极显著[F(2,24)=9.972,P=0.001],平衡1h极显著小于平衡2 h和4 h的精液活力(P=0.003,P=0.000),以平衡4 h最好。用筛选的冷冻—解冻方法处理精液,解冻后精子的活力极明显降低(P=0.002);生存指数降低,GOT释放量增加,菌落数减少,与鲜精相比差异显著(P=0.018;P=0.016;P=0.018);精子畸形率增加,顶体完整率降低,与鲜精相比差异不显著(P=0.494;P=0.084)。结论优化了提高精子转染外源DNA效率的山羊精液冷冻—解冻方法。     

Phylogenetic analysis and reclassification of caprine and ovine lentiviruses based on 104 new isolates: evidence for regular sheep-to-goat transmission and worldwide propagation through livestock trade

We performed a phylogenetic analysis of caprine and ovine lentiviruses using long sequences in gag and pol of 104 new Swiss isolates and six available corresponding database sequences. Forty-five isolates, forming five sequence clusters, were unclassifiable by the present classification. Pairwise DNA distance analysis indicated different categories of relatedness, requiring a new classification system. We propose four principal sequence groups, A-D, which differ by 25-37%. Groups A and B are further divided into subtypes which differ by 15-27%. Group D and four of the seven group A subtypes, A3, A4, A5 and A7, are formed by new Swiss isolates. Molecular epidemiology revealed that Swiss B1 strains differed no more from French, Brazilian or US strains than from each other, suggesting virus propagation through international livestock trade. Furthermore, infection of goats by subtypes A3 or A4 was significantly associated with documented contact with sheep, which also harbor these subtypes, thus indicating regularly occurring sheep-to-goat transmission.     

普罗帕酮在短期电重构后山羊心房的抗心律失常作用研究

为研究普罗帕酮对短期电重构后清醒山羊心房的电生理特性的影响,探讨其抗心律失常作用的可能机制,在7只山羊的左房游离壁外膜缝合4对电极,经皮下隧道将电极导线引至颈部皮肤外。术后2周测量不同基础刺激周长(BCL)时的心房有效不应期(AERP)、BCL为200ms时的心房传导速度(CV)并计算心房波长(WL)。心房快速刺激维持心房颤动(简称房颤)6h后静脉滴注(简称静滴)生理盐水,重复上述指标测量。2天后,在房颤6h后静滴普罗帕酮,重复上述测量。结果:①在基础状态下,AERP表现出频率适应性;②6h的房颤后,在静滴生理盐水时,AERP的频率依赖特性丧失。BCL为200ms时,AERP及WL均缩短,CV变化不显著;③在静滴普罗帕酮时,AERP显示使用依赖特性。BCL为200ms时,与基础状态时比较,AERP延长,CV及WL缩短;但与静滴盐水时相比,WL无明显变化。结论:在经过6h的电重构后,普罗帕酮使AERP表现为使用依赖特性。快速心房刺激时,普罗帕酮使AERP明显延长,CV明显缩短。     

Dietary cancer risk from conditional cancerogens (tumor promoters) in produce of livestock fed on species of spurge (Euphorbiaceae)

The feeding of lactating goats on usual green fodder, contaminated with Euphorbia helioscopia or E. nubica, results in poisoning of the dams as well as their suckling kids. General signs of toxicity were emaciation, depression, shedding of body hair, arching of back, and possible death. Post-mortem changes of dams and dead suckling kids included congestion and hemorrhage in cardiac muscle, lung, liver, and kidneys. Blood analyses of goats exposed to these contaminants showed an increased level of serum alanine amino transferase compared to control samples, indicating cellular destruction in the liver. The latter was confirmed by histopathological changes in the organ which include severe congestion, necrosis, and degenerative changes. The goats also suffered from deterioration of renal function as indicated by increased blood urea nitrogen and creatinine levels. In histopathologic inspections of kidney, severe congestion, hemorrhage in the cortex and medulla, as well as necrosis of epithelial cells of kidney tubules were noticed. Considerable degenerative changes were also observed in heart and lung. The pathophysiological appearances indicate that by feeding on the Euphorbia species mentioned above, the goats are poisoned in a way similar to the case of E. peplus reported previously. Such intoxication most likely is due to irritant and hyperplasiogenic diterpene ester (DTE) toxins, usually present in the aerial parts of Euphorbia species and well known as tumor promoters in mouse skin. After ingestion of the toxic plant parts by the goats, the DTE toxins might be metabolized and thereby partially detoxified. Yet, at least in part, they may show up in the milk of the goats, as indicated by severe poisoning of their suckling kids. As discussed previously in lactating goats fed on fodder contaminated with E. peplus, tumor promoters of the DTE type may enter the human food chain via this source of milk. Such milk may be considered a valuable etiologic model for the investigation of economic, ecologic, and public health problems raised by human diet polluted with tumor promoters, i.e., conditional (non-genotoxic) cancerogens. Received: 25 July 2000 / Accepted: 18 September 2000     

Magnesium sulfate exposure increases fetal blood flow redistribution to the brain during acute non-acidemic hypoxemia in goats

BACKGROUND: It is still controversial that intrapartum exposure to magnesium may or may not reduce brain damage in premature infants in human and animal models. AIMS: We investigated the effect of hypoxemia alone under magnesium exposure on fetal cardiovascular changes in chronically catheterized goat fetuses. STUDY DESIGN: We performed a 3-day experimental protocol with control (10% glucose) on day 1, recovery on day 2, and magnesium on day 3. Magnesium sulfate was directly infused to fetuses in a bolus dose of 270 mg/kg followed by 80 mg/kg/h. Hypoxemia was induced by maternal inhalation of nitrogen gas on day 1 and on day 3. Cerebral blood flow was measured by colored microsphere techniques. Repeated measure ANOVA and Bonferroni's/Dunn's test were used for comparison. SUBJECTS: Six Japanese Saanen goats at 0.85 gestation. OUTCOME MEASURES: Fetal heart rate, blood pressure, and cerebral blood flow. RESULTS: Ionized magnesium concentrations were significantly increased. Fetal PO2 decreased significantly from 30 mmHg to 14 mmHg without acidemia. Magnesium exposure significantly attenuated hypoxemia-induced bradycardia but did not affect blood pressure. Hypoxemia significantly increased fetal brain blood flow from the pre-hypoxic levels on day 1. Magnesium exposure further increased hypoxemia-induced brain blood flow on day 3, but statistical significance was limited to the cerebral cortex. CONCLUSION: In near-term, initially healthy goat fetuses, brain blood flow during acute hypoxemia was significantly increased with magnesium sulfate exposure.     

Time-dependent tegumental surface changes in juvenile Fasciola gigantica in response to triclabendazole treatment in goat

Triclabendazole (TCBZ), the anthelmintic drug active against both mature and immature liver flukes, was used to investigate the effect of in vivo treatment on the tegumental surface of juvenile Fasciola gigantica. Five goats were infected with 150 F. gigantica metacercariae each by oral gavage. Four of them were treated with single dose of TCBZ at 10 mg/kg at four weeks post-infection. They were euthanized at 0 (untreated), 24, 48, 72 and 96 h post treatment. Juvenile flukes were manually retrieved from the goat livers and processed for scanning electron microscopy. In control flukes, the anterior region was adorned with sharply pointed spines projecting away from the surface, while in the posterior region, spines become shorter and narrower, loosing serration and with the appearance of distinct furrows and papillae. The dorsal surface retained the same pattern of surface architecture similar to that of ventral surface. Flukes obtained from 24 h post-treatment did not show any apparent change and were still very active. However, there were limited movements and some blebbing, swelling, deposition of tegumental secretions and some flattening displayed by the flukes of 48 h post-treatment. All the worms were found dead 72 h post-treatment and showed advanced level of tegumental disruptions, consisting of severe distortion of spines, sloughing off the tegument to expose the basal lamina, formation of pores and isolated patches of lesions. By 96 h post-treatment, the disruption was extremely severe and the tegument was completely sheared off causing deeper lesions that exposed the underlying musculature. The disruption was more severe at posterior than anterior region and on ventral than dorsal surface. The present study further establishes the time-course of TCBZ action in vivo with 100% efficacy against the juvenile tropical liver fluke.     

Bone marrow stromal cells on a three-dimensional bioactive fiber mesh undergo osteogenic differentiation in the absence of osteogenic media supplements: The effect of silanol groups

Osteogenic differentiation is a tightly regulated process dependent on the stimuli provided by the micro-environment. Silicon-substituted materials are known to have an influence on the osteogenic phenotype of undifferentiated and bone-derived cells. This study aims to investigate the bioactivity profile as well as the mechanical properties of a blend of starch and poly-caprolactone (SPCL) polymeric fiber mesh scaffolds functionalized with silanol (Si–OH) groups as key features for bone tissue engineering strategies. The scaffolds were made from SPCL by a wet spinning technique. A calcium silicate solution was used as a non-solvent to develop an in situ functionalization with Si–OH groups in a single-step approach. We also explored the relevance of silicon incorporated in SPCL–Si scaffolds to the in vitro osteogenic process of goat bone marrow stromal cells (gBMSCs) with and without osteogenic supplements in the culture medium. We hypothesized that SPCL–Si scaffolds could act as physical and chemical millieus to induce per se the osteogenic differentiation of gBMSCs. Results show that osteogenic differentiation of gBMSCs and the production of a mineralized extracellular matrix on bioactive SPCL–Si scaffolds occur for up to 2 weeks, even in the absence of osteogenic supplements in the culture medium. The omission of media supplements to induce osteogenic differentiation is a promising feature towards simplified and cost-effective cell culturing procedures of a potential bioengineered product, and concomitant translation into the clinical field. Thus, the present work demonstrates that SPCL–Si scaffolds and their intrinsic properties sustain gBMSC osteogenic features in vitro, even in the absence of osteogenic supplements to the culture medium, and show great potential for bone regeneration strategies.     

促性腺激素释放激素受体在雌性山羊颈胸神经节中的分布

目的探讨颈胸神经节是否具备接受促性腺激素释放激素(GnRH)作用的条件。方法实验采用免疫组织化学SP法,观察GnRH受体在雌性山羊颈胸神经节中的分布特点。结果在颈胸神经节中,神经元胞体均为GnRH受体免疫反应阳性,其细胞膜以及膜下胞质中的颗粒状物质呈棕黄色,GnRH受体为强阳性表达,而胞核呈阴性表达。部分神经元可见其突起,呈黄色,GnRH受体为中等阳性表达。卫星细胞也呈黄色,GnRH受体为中等阳性表达。图像分析表明,呈阳性反应的神经元胞体与节内其他阳性成分相比,其GnRH受体相对表达量差异性极显著(P0.01)。结论在雌性山羊颈胸神经节中,神经元胞体是GnRH发挥作用的主要靶细胞,颈胸神经节具备接受GnRH作用的条件。提示GnRH有可能通过作用于颈胸神经节交感节后神经元上的GnRH受体来影响心肺器官的功能活动,即颈胸神经节可能是心肺功能活动中协调GnRH内分泌调节和该神经节自主神经调节两途径之间的中继站。