丝裂霉素C和γ射线对小鼠胎儿成纤维细胞饲养层制备的影响

用丝裂霉素C和γ射线对小鼠胎儿成纤维细胞进行处理，观察它们对小鼠胎儿成纤维细胞分裂与存活的影响。结果表明，小鼠胎儿成纤维细胞用不同浓度的丝裂霉素C或不同强度的)，射线处理一定时间(5μg／mL 4h、10μg／mL 1～4h、20μg／mL 1．0～2．5h或14Gy 1h、21Gy 1h、28Gy 1h)，能有效地抑制其分裂，且不影响其活力。     

丝裂霉素C对ICR小鼠胚胎成纤维细胞饲养层制备的影响

目的：探索不同浓度的丝裂霉素c（MMC）处理对ICR小鼠胚胎成纤维细胞饲养层制备的影响,用于分离和培养干细胞。方法：取13．5d胎龄ICR鼠胚分离原代成纤维细胞,利用不同浓度MMC处理胚胎成纤维细胞制备饲养层,比较观察MMC对细胞增殖的抑制作用,制作细胞生长曲线;取妊娠3．5d的ICR小鼠胚胎在不同浓度MMC处理的饲养层上培养,观察胚胎贴壁和增殖情况。结果与结论：胎儿成纤维细胞贴壁生长,增殖迅速,6代后细胞逐渐衰老;MMC能有效抑制胎儿成纤维细胞的增殖,最佳处理方法为20μg／ml、2h。妊娠3．5d的ICR小鼠胚胎在10、20μg／mlMMC处理的饲养层上孵出率和贴壁率显著高于5／Lg／mlMMC处理的饲养层,在5、10和20μg／m[MMC处理的饲养层上,内细胞团增殖率无显著差异。因此,ICR小鼠胚胎成纤维细胞最佳处理方法为20μg／mlMMC作用2h。     

小鼠胚胎成纤维细胞饲养层制备条件的研究

为了建立活力稳定的小鼠胚胎成纤维细胞饲养层,本实验以13．5～14．5d的ICR小鼠胚胎为实验材料,以MTT法测定细胞活力,探讨了不同浓度的丝裂霉素C、丝裂霉素C不同处理时间及不同的成纤维细胞接种密度对MEF活力的影响。结果表明：10μg／ml的丝裂霉素C处理后的MEF活力比其他浓度（1μg／ml、5μg／ml、20μg／ml、30μg／ml）丝裂霉素C处理后的MEF活力稳定;用10μg／ml的丝裂霉素C处理2．5h,MEF活力比处理1．5h、3．5h、4．5h稳定;以2．5～35×10^5／ml密度接种于96孔板上,每孔200μl,MEF活力较接种密度为1．5×10^5／ml、4．5×10^5／ml、7．5×10^5／ml稳定。结论：用10μg／ml丝裂霉素C处理MEF 2．5h,2．5～3．5×10^5／m;密度接种于96孔板上,每孔200μl,以10％的胎牛血清培养液培养能得到活力稳定高效的小鼠胚胎成纤维细胞饲养层。     

人类α-actin 启动子真核表达载体的构建及应用

利用PCR技术克隆了人类α-actin基因的启动子（约450bp），尝试用去掉启动子的pEGFP—N1作为框架结构，成功构建了真核表达载体pEGFP-N1-α-actin—P。应用Lipofectamine 2000将所构建的pEGFP-N1-α-actin-P转染入小鼠ES细胞。通过比较，发现在本实验室条件下，质粒DNA浓度以3．0～5．0μg／mL，转染时间约在2～3h最佳。200μg／mL的G418较适宜于靶细胞的转染与筛选。得到表达心肌a—actin和GFP的小鼠ES细胞，基本维持小鼠ES细胞的形态。PCNA染色结果表明，转染后的小鼠ES细胞具有增殖能力。α—actin抗体免疫组化染色结果表明，转染后细胞表达α-actin和GFP，揭示构建的真核表达载体pEGFP-N1-α-actin-P转染小鼠ES细胞，可能促进其向心肌细胞分化并对其筛选。     

不同体外培养条件对家兔早期囊胚贴壁行为的影响

采集家兔自然交配后96h的早期囊胚，以低糖DMEM＋150mL／L胎牛血清＋0．1mmol／L非必需氨基酸＋100IU／mL青霉素＋100IU／mL链霉素为基础培养基，比较了不同胚胎处理方法、不同饲养层以及培养液中添加不同成分对兔早期囊胚贴壁和增殖的影响，以完善兔胚胎干细胞的建系方法。结果表明，以胚胎分割法和链霉蛋白酶-E（proteinaseE）处理掉黏蛋白及部分透明带的胚胎容易贴壁和增殖；在小鼠成纤维细胞饲养层和兔胎儿成纤维细胞饲养层上，胚胎的脱带率差别不大，但在小鼠成纤维细胞饲养层上贴壁率明显提高，且贴壁后内细胞团增殖较快；添加胰岛素、白血病抑制因子和伊巯基乙醇均利于抑制ES的分化和促进内细胞团的增殖。     

银杏叶复方对脾虚小鼠小肠淋巴细胞体外增殖的影响

为了探究不同浓度的银杏叶复方在脂多糖(LPS)或植物血凝集素(PHA)刺激下对脾虚小鼠小肠淋巴细胞体外增殖的影响,试验用不同浓度的银杏叶复方(200μg/mL、100μg/mL、10μg/mL、1μg/mL、0.1μg/mL)同LPS或PHA刺激小肠淋巴细胞分裂增殖的方法研究对小鼠淋巴细胞体外增殖的影响。结果表明:对于脾虚小鼠小肠B淋巴细胞,以200μg/mL、100μg/mL的浓度刺激效果最佳(P0.05);相比于1μg/mL、0.1μg/mL浓度,浓度为200μg/mL时更有利于正常小鼠小肠B淋巴细胞增殖(P0.05);对于脾虚小鼠小肠T淋巴细胞,以100μg/mL浓度最佳(P0.05),浓度为200μg/mL和100μg/mL时对正常小鼠小肠T淋巴细胞的刺激增殖效果显著(P0.05)。说明银杏叶复方浓度为200μg/mL、100μg/mL时能有效刺激正常和脾虚小鼠的小肠淋巴细胞分裂增殖。     

丝裂霉素C对小鼠胎儿成纤维细胞增殖抑制作用的研究

为探讨丝裂霉素C对小鼠胎儿成纤维细胞增殖的抑制作用,用10μg/mL的丝裂霉素C处理昆明白胎鼠P1代成纤维细胞1.5、2、2.5、3、3.5、4 h,用台盼蓝和AO/PI染色法观察细胞死亡情况,MTT测其增殖情况,PCNA染色观察其增殖细胞状态,比较胚胎干细胞接种在冻存过的饲养层细胞与未冻存的饲养层细胞的生长情况.结果表明,丝裂霉素C处理MEF时间小于3 h,不能抑制其生长,处理4 h后,饲养层细胞部分已经没有核仁,部分细胞已经崩解,且胚胎干细胞接种在冻存过的饲养层细胞与未经冻存的饲养层细胞都生长良好.从而得出,10μg/mL的丝裂霉素C处理MEF 3 h,能够抑制细胞增殖,且不引起细胞死亡,能用来作ES细胞的饲养层,且可以冻存、复苏后直接用于培养胚胎干细胞.     

藏药材在鸡胚成纤维细胞体系中安全浓度的测定

用MTT法测定了藏菖蒲、红景天、决明子、灵芝菌盖、灵芝菌柄、龙胆、天冬、降香、乳香、仁青芒觉、二十五味珍珠丸和二十五味松石丸12种藏药在鸡胚成纤维细胞（CEF）培养体系中的安全浓度。结果表明,各藏药的最大安全浓度分别为红景天31．25ng／mL,天冬、降香、决明子和二十五味松石丸为62．5μg／mL,乳香为125μg/mL、二十五味珍珠丸为250μg／mL,藏菖蒲和灵芝菌柄为1000μg／mL,龙胆和仁青芒觉为2500μg／mL,灵芝菌盖为5000μg／mL;藏菖蒲在1．954～500μg／mL、天冬在1．954～15．625μg／mL、决明子在1．954～3．907μg／mL、灵芝菌柄在1．954～7．813μg／mL、仁青芒觉在19．54～1250μg／mL、龙胆在312．5～625μg／mL范围内能显著促进细胞生长。     

牛磺鹅去氧胆酸对小鼠机体cAMP和cGMP含量的影响

为了研究牛磺鹅去氧胆酸(TCDCA)对小鼠机体环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)含量的影响,试验用环孢菌素A诱导特异性免疫低下模型,按相应组别对应的剂量对小鼠灌胃给药7 d,获取血清;体外培养正常小鼠腹腔巨噬细胞,用MTT方法筛选TCDCA作用于腹腔巨噬细胞的最佳药物浓度;用最佳药物浓度作用于巨噬细胞后超声破碎,获取上清液;ELISA方法测定血清和上清液中cAMP和cGMP的含量。结果表明:在TCDCA高剂量(0.2 g/kg)组小鼠血清中,cAMP含量极显著高于环孢菌素A组(P<0.01);各组小鼠血清cGMP含量差异不显著(P>0.05);TCDCA促进小鼠腹腔巨噬细胞增殖的体外浓度为1μg/mL、2.5μg/mL、5μg/mL、10μg/mL;1μg/mL、2.5μg/mL、5μg/mL的TCDCA均能显著或极显著提高细胞内cAMP含量(P<0.05或P<0.01),对cGMP含量均没有显著影响。说明TC-DCA能够显著提高正常和免疫抑制小鼠血清中和正常腹腔巨噬细胞内cAMP含量。     

长效土霉素注射液在猪体内的药代动力学研究

建立了土霉素在猪血浆中含量测定的高效液相色谱法，研究了其在猪体内的药代动力学。土霉素检测的线性范围为0．25～32．0lμg／mL，相关系数为0．9997，最低定量限为0．25μg／mL。药代动力学研究表明，给猪单剂量肌肉注射土霉素25mg／kg体重后，其血药浓度一时间曲线符合一级吸收二室模型，参数为Tmax=2h,Cmax=7．62lμg／mL,t1/2β=69．315h，V1／F=4．648L／kg，说明长效土霉素在体内逐渐吸收和广泛分布后，在组织中能长时间地维持较高的血药浓度，能达到长效之目的。本试验能对兽药药代动力学研究和制定长效土霉素注射液合理给药方案提供参考。     

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.     

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.     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -