肠道类器官的构建及其在畜禽营养和肠道健康研究中的应用

肠道类器官是由肠干细胞、多能干细胞或肿瘤干细胞在3D培养条件下自我更新、分化、组装而成的一种体外培养物,它包含多种类型肠道内皮细胞,能有效模拟肠黏膜功能,可以作为研究畜禽营养、肠道生理和肠道病理的体外模型。不同畜禽肠道类器官的分离、培养方法和条件存在差异,因此优化不同畜禽肠道类器官的构建方法并开展相关的生理、病理学机制探索是当前的研究热点之一。本文较为系统地介绍了畜禽肠道类器官的分类、特性及其分离、培养和鉴定的方法,并总结了近年来肠道类器官在畜禽营养与肠道健康相关研究中的应用,希望能为畜禽肠道类器官培养和相关研究提供参考。     

微血管内皮细胞膜上的离子通道及其功能

近年来,随着对微血管内皮细胞电生理特性的深入研究,发现膜上存在有多种离子通道。这些离子通道可通过直接或间接的方式影响钙信号的传导,从而调节微血管内皮细胞的分泌、增生及基因表达,参与多种生理和病理过程。因此,微血管内皮细胞膜上的离子通道可能是多种病理过程的重要环节和药物调节细胞功能的潜在靶点。对微血管内皮细胞膜上的离子通道功能的研究,不但有助于揭示多种疾病的病理机制,而且有助于新型药物的开发。文章综述了近年来在微血管内皮细胞膜上的离子通道种类、特性及其功能研究方面取得的进展,以期为进一步的相关研究提供资料。     

大鼠肺微血管内皮细胞的体外分离培养与纯化

旨在建立一种简单易行、获得细胞纯度较高的体外分离、培养大鼠肺微血管内皮细胞的方法。取5~7日龄SD大鼠分离外周肺组织,组织植块法获得原代大鼠肺微血管内皮细胞,37℃、5%CO_2培养箱中传代培养,采用免疫磁珠法对其进行分离纯化,并对分离纯化后的细胞进行免疫荧光及流式细胞鉴定,通过MTT比色分析法准确、安全、可靠地检测纯化后传代肺微血管内皮细胞的增殖情况。结果显示:倒置显微镜下观察单个细胞呈短梭形或多角形,汇合后呈铺路石样,单层贴壁生长,细胞分离纯化后经免疫荧光检测CD31呈阳性,流式细胞仪检测淋巴管内皮细胞表面特有标记VEGFR-3呈阴性(P=0.1,且P0.5),且复苏后经MTT测得传代细胞的增殖情况良好。成功建立了一种分离高纯度大鼠肺微血管内皮细胞的体外培养方法。     

胎牛子宫类器官及内膜上皮细胞的分离培养

建立胎牛子宫类器官及内膜上皮细胞分离培养方法,为研究病毒、细菌、营养元素以及毒物等与子宫相互作用机理提供研究平台和模型。试验采用4～6月龄胎牛子宫为研究对象,对子宫组织进行类器官培养,比较不同胎龄胎牛子宫类器官培养成功率,然后从类器官出芽组织分离获得原代子宫内膜上皮细胞,并与组织块分离法培养的细胞形态学、纯化培养、生长速度等方面进行比较,采用免疫细胞化学法对获得的子宫内膜上皮细胞进行角蛋白表达的鉴定。结果表明用子宫内膜组织进行类器官培养,4月龄胎牛子宫类器官的出芽率显著高于5、6月龄(P0.05)。通过类器官出芽进行原代子宫内膜上皮细胞的培养,相较于传统的组织块分离法,更易获得子宫内膜上皮细胞,且获得的细胞形态良好,纯度在95%以上,能够稳定传至8代。研究表明,低月龄的胎牛子宫组织块更易于获得类器官;通过类器官出芽组织获得子宫内膜上皮细胞是一种较为简便、高效的方法,且形态均一、活性好,传代时间更长。     

猪脑微血管内细胞的原代分离培养与鉴定

探讨获取纯度较高的原代猪脑微血管内皮细胞的分离和培养方法。采用1月龄的三元杂交猪,通过两次酶消化、BSA和Percoll非连续梯度离心获得较纯的脑微血管段后,接种于涂布有鼠尾胶的培养瓶进行原代培养;相差显微镜观察细胞并进行纯化和传代,采用Ⅷ因子相关抗原免疫荧光检测法对培养的细胞进行鉴定。结果表明,培养24 h即可见细胞从贴壁的脑微血管段周围爬出,细胞呈短梭形,集落呈典型的"鹅卵石样",区域性单层生长,6~7 d内皮细胞开始融合,血管内皮细胞特异性标志物Ⅷ因子相关抗原表达阳性。说明本试验成功的培养出了纯度较高的脑微血管内皮细胞,为后续的体外血脑屏障模型的建立奠定了基础。     

微血管内皮细胞功能的研究进展

文章回顾了微血管内皮细胞功能的研究概况。微血管内皮细胞是位于循环血液与组织液之间的单层扁平上皮细胞,不但构成了微血管通透性的主要物理屏障,保证微血管内、外正常的物质交换,而且是一种多功能的分泌细胞,通过合成并释放多种舒张因子和收缩因子以维持正常的血管紧张度;通过合成、释放多种促凝血因子和抗凝血因子,维持血液的正常状态和动态平衡。还通过其屏障和分泌功能,影响着炎症反应的发生、发展,并通过多种途径参与调节机体的免疫应答。微血管内皮细胞结构的完整性被破坏,分泌功能失调,势必导致相应组织器官的功能障碍而引发多种病理过程,从而会引发内皮细胞机能障碍和休克、感染、肿瘤、创伤、水肿、急性炎症等多种疾病。     

大鼠脑皮质微血管内皮细胞的分离培养及鉴定

本研究目的在于建立一种简易可行、获得细胞纯度较高的体外分离、培养大鼠脑皮质微血管内皮细胞的方法,为进一步研究其功能打好基础。新生SD大鼠,分离大脑皮质,经匀浆、两步过滤法获得大鼠脑微血管段,用胶原酶消化后,在37℃、5%CO2培养箱中进行原代细胞培养。通过差速消化和差速贴壁方法并结合倒置显微镜下形态学的观察进行传代和纯化,利用第Ⅷ因子相关抗原免疫荧光检测法对培养的细胞进行鉴定。结果显示:成功分离培养了大鼠脑微血管内皮细胞,倒置显微镜下单个细胞呈多角形,互相融合后呈"铺路石"样,单层贴壁生长;免疫荧光检测第Ⅷ因子相关抗原呈阳性。说明本研究建立的大鼠脑微血管内皮细胞的体外培养方法,程序简单,获得的细胞纯度较高。     

细毛羊毛囊干细胞分离培养方法比较研究

试验旨在对细毛羊毛囊干细胞的分离培养方法进行初步研究,建立细毛羊毛囊干细胞体外培养体系。采用两步酶消化法、机械分离法和两步酶消化法+机械分离法3种方法分离培养细毛羊毛囊干细胞,通过测定毛囊干细胞的数量、克隆形成率及毛囊干细胞的增殖能力等综合评估3种培养方法的优劣,寻求既能方便获得大量毛囊干细胞,又能减少其分化的理想培养条件。倒置显微镜下观察3种培养方法获得的细胞均为铺路石状,均表达角蛋白K19和整合素β1,表明成功获得细毛羊毛囊干细胞,建立体外培养体系。采用"两步酶消化法和机械分离法"相结合的方法获得毛囊干细胞体外培养效果最优。     

小肠上皮细胞分离纯化方法的研究进展

小肠是消化吸收的重要部位,用获取的小肠上皮细胞来研究小肠功能、营养物质吸收机制等具有重要意义,而成功分离小肠上皮细胞则是前提,可以用组织块培养法、非酶学消化法、酶消化分离法等来分离小肠上皮细胞。本文就目前国内外分离小肠上皮细胞的方法进行了综述。     

肉鸡肺微血管内皮细胞的培养与鉴定

选用17d鸡胚,采用组织块培养法,在无菌条件下分离培养肺微血管内皮细胞(PMVECs),60 h移除组织块,结合细胞形态和免疫细胞化学对培养细胞进行鉴定.结果表明,培养24 h组织块周围即有细胞爬出,48 h后细胞大量增殖.形状以梭形或多边形居多,细胞扁平排列紧密,大小均匀,融合为单层后呈现出典型的鹅卵石外观.异植物血凝素(FITC-BSI)结合试验、CD31单抗和Ⅷ因子相关抗原免疫染色均呈阳性反应,证明分离培养细胞为PM-VECs.本试验提出的组织块培养法操作简单,对仪器设备要求不高,能较快且稳定地在体外培养出PMVECs,该方法的建立有助于家禽心血管疾病,如肺动脉高压、腹水和肺血管结构重构等相关疾病的深入研究.     

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