氧化应激在硝基苯致小鼠肾损伤中的作用

为探讨硝基苯对小鼠肾的毒性作用，采用灌胃法对试验小鼠用硝基苯进行染毒，染毒剂量分别为26、52、105mg／kg，每天染毒1次，共30d。于末次染毒后第2d将小鼠脱颈处死，立即取出肾通过相应处理用于抗氧化指标检测及显微和超微结构的观察。结果，染毒小鼠主要表现为近曲小管上皮细胞不同程度水样变性，线粒体肿胀，脊断裂；内质网脱核糖颗粒；细胞核发生形变；肾小球血管内皮细胞肿胀，血管扩张；随着染毒剂量的加大，肾和血清中MDA含量逐渐升高，SOD和GSH—Px酶活性不断降低，与对照组比较，均差异显著（P〈0．05）或极显著（P〈0．01）。结果表明，硝基苯能够诱发小鼠肾细胞发生氧化胁迫，并诱导细胞凋亡的发生。     

磺胺喹噁啉对小鼠睾丸的病理损害及生精细胞凋亡作用

按毒理学方法给雄性小鼠灌喂不同剂量磺胺喹噁啉,检测对小鼠睾丸的病理学损害,探讨其对雄性小鼠生殖器官产生的可能危害,采用DNA Ladder条带和TUNEL法检测了磺胺喹噁啉对生精细胞凋亡的影响。结果表明：1／30LD50组和1／20LD50组精原细胞、初级精母细胞、次级精母细胞和精子细胞基本正常,仅少部分核出现形状不规则的现象。而1／10LD50组和1／10LD50组则病理变化明显,表现为部分曲精小管上皮细胞减少、分层不明显;各级生精细胞细胞膜部分破损、有细胞质溶解现象,核体积皱缩或轮廓不清,核膜有溶解,细胞内线粒体嵴减少或外膜破损;成熟的精子细胞数量减少或从支持细胞上脱落。小鼠睾丸DNA Ladder条带检测结果表明磺胺喹噁啉对诱导生精细胞凋亡没有明显的作用,原位末端标记法检测磺胺喹噁啉各用药组小鼠生精细胞凋亡指数均有所增加,但较对照组差异不显著（P〉0．05）,也没有表现出明显的正相关变化。说明大剂量使用磺胺喹噁啉会对小鼠睾丸产生器质性的损害,但对睾丸生精细胞凋亡没有明显的诱导或抑制作用。     

硝基苯染毒致小鼠脑的毒性作用

为探讨硝基苯染毒致小鼠脑的毒性作用,用灌胃的方法对试验小鼠进行了硝基苯染毒,染毒剂量分别为26、52、105mg／kg,每日染毒1次,共30d。于末次染毒后第2d将小鼠脱颈椎处死,立即取出脑,检测SOD和GSH—Px活性和．MDA含量,并对其显微及超微结构进行了观察。结果,硝基苯对小鼠脑有明显的毒性作用,主要表现为大脑血管间隙扩大,周围神经纤维疏松;小脑、海马区部分浦肯野氏细胞核固缩、核溶解,锥体细胞核固缩;神经细胞肿胀,线粒体明显肿胀,粗面内质网形态扩张;大部分胶质细胞电子密度增加,胞核变小、核固缩,胞质内细胞器明显减少;有些神经纤维脱髓鞘,神经微丝溶解;随着染毒剂量的加大,MDA含量逐渐升高,CAT和SOD活性不断显著降低。结果表明,硝基苯可以通过氧化应激和诱发细胞凋亡对小鼠脑组织造成损伤。     

玉米赤霉烯酮对Leydig细胞凋亡及caspase-9、caspase-3蛋白表达的影响

以不同浓度的玉米赤霉烯酮（Zearalenone,zEA）对大鼠睾丸间质细胞（Leydig）细胞进行染毒,采用噻唑蓝比色法观察了ZEA对Leydig细胞活力的影响;流式细胞术分析检测了ZEA对细胞的凋亡率、线粒体膜电位变化的影响;Westernblotting等技术检测了Bax、Bcl-2、caspase-3、caspase-9、PARP蛋白的表达情况。结果显示,ZEA可明显抑制睾丸Leydig细胞的活力（染毒各组与对照组比较P〈0．05）,40mg／L染毒组相对活力为40．67％;与对照组比较,5、10、20mg／LZEA染毒组睾丸Leydig细胞凋亡率均极显著升高（P〈0．05）,呈明显剂量关系;线粒体膜电位变化测定显示,各染毒组与对照组比,线粒体膜电位均下降（P〈0．05）,且有明显的剂量关系;Westernblotting分析显示,与对照组比较,5、10、20mg／LZEA染毒组Bax、caspase-9、caspase-3、PARP蛋白表达均上调,bel-2蛋白表达均下调。结果表明,ZEA能诱导大鼠睾丸间质细胞发生凋亡,Bax、Bcl-2、caspase-9、caspase-3等基因参与ZEA诱导Leydig细胞凋亡的调控。     

钼对TM3小鼠睾丸间质细胞周期和凋亡的影响

以体外培养的小鼠睾丸间质细胞系TM3 为材料,加入不同质量浓度的钼酸钠溶液（0,10,20,40,80,160mg/L）染毒培养,分别在干预4,8,12,24,48h采用MTT法检测细胞的增殖。干预48h后,采用流式细胞术检测细胞周期和凋亡,单细胞凝胶电泳检测DNA损伤的变化。结果表明：与对照组相比,不同剂量钼酸钠作用24h后,睾丸间质细胞的增殖活性均受到抑制;不同质量浓度的钼酸钠作用48h后,细胞周期阻滞于G0/G1期,20mg/L及其以上剂量组G0/G1期细胞百分率与对照组相比显著升高（P〈0.05或P〈0.01）;与对照组相比,各剂量组TM3 小鼠睾丸间质细胞凋亡率显著升高,差异极显著（P〈0.01）;细胞尾部DNA含量及细胞尾长随着钼剂量的增加呈不同程度的增加,且存在着剂量—效应关系。结论说明钼能够引起睾丸间质细胞周期的紊乱,并诱导睾丸间质细胞发生DNA损伤和凋亡。     

氯化汞对SD大鼠脑组织氧化损伤的影响

24只SD大鼠被随机均分为4组,即C组为对照组（饮用蒸馏水）,L组为汞低剂量组（50mg／L）,M组为汞中剂量组（100mg／L）,H组为汞高剂量组（200mg／L）,采用自由饮水染毒,染毒时间为21d。采用半自动生化分析仪测定汞对SD大鼠脑组织谷胱甘肽过氧化物酶（GSH—Px）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性及总抗氧化能力（T—AOc）和丙二醛（MDA）含量的影响。结果显示,与对照组比较,各染毒纽GSH—Px、SOD和CAT活性及T—AOC均呈下降趋势,部分参数差异显著（P〈0．05）,而MDA含量则显著升高（P〈0．05）。结果表明,低刘量汞暴露对SD大鼠脑组织主要抗氧化酶活性有明显抑制作用,显著降低动物机体的抗氧化能力。     

槲皮素对双酚A致小鼠生精功能障碍的治疗作用

将50只雄性昆明小鼠随机分为5组,A组（n=10）正常喂饲,B、C、D、E组（各10只）小鼠均腹腔注射50mg／kg·d的BPA,1次／d,连续注射7d,构造小鼠睾丸损伤模型,同时C、D、E组分别用100、200、400mg／kg·d浓度的Que灌胃7d,A组和B组给予等量生理盐水。记录小鼠的体征、体质量变化及试验结束时睾丸、附睾和精囊腺的质量;试剂盒检测血清中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GsH—Px）和丙二醛（MDA）的含量;酶联免疫法测定血清睾酮（T）、黄体生成素（LH）和促性腺激素释放激素（GnRH）的水平;对睾丸组织进行组织学观察。结果显示：D组200mg／kg·d小鼠体质量、各脏器质量均较B组有明显改善（P〈O．05或P〈0．01）,接近A组,C组和E组只有附睾质量变化显著（P〈0．05）;Que各剂量组血清中的SOD、GSH—Px活性均高于BPA组,差异极显著（P〈0．01）,其中D组抗氧化酶的活性最高;MDA测定结果显示,D组明显降低,差异极显著（P〈0．01）,E组也有所降低,差异显著（P〈0．05）;C、D、E组小鼠血清生殖激素水平均有一定程度的恢复,但D组各生殖激素指标均接近A组;组织学观察见各给药组睾丸生精小管生精细胞层数、精子数目均高于B组,尤以D组200mg／kg·d恢复最为明显。结果表明：Que能够促进BPA致小鼠睾丸生精功能障碍后生精功能的恢复,且最佳剂量为200mg／kg·d。     

纳米氧化锌对小鼠的亚慢性损伤研究

为检测纳米氧化锌对小鼠的亚慢性损伤作用,以不同剂量经口连续染毒纳米氧化锌,90d后摘眼球取血,对血常规、肝功、肾功、抗氧化指标进行检测。并扑杀各组小鼠,取肝脏、肾脏等组织,切片后经HE染色观察染毒小鼠的病理损伤。结果发现,40、160及320mg/kg剂量组小鼠红细胞数显著低于对照组(P0.05);40mg/kg剂量组小鼠血红蛋白含量极显著低于对照组(P0.01)。40mg/kg剂量组小鼠谷丙转氨酶(ALT)活性显著高于对照组(P0.05)。80、320mg/kg剂量组小鼠谷草转氨酶(AST)活性显著高于对照组(P0.05)。80、160mg/kg剂量组小鼠血清肌酐含量极显著高于对照组(P0.01)。各染毒组小鼠血清超氧化物歧化酶(SOD)活性极显著高于对照组(P0.01)。40、80及320 mg/kg剂量组小鼠血清抑制羟自由基能力极显著低于对照组(P0.01)。40mg/kg剂量组丙二醛(MDA)含量极显著高于对照组(P0.01)。80mg/kg剂量组小鼠血清过氧化氢酶(CAT)活性极显著高于40、160及320mg/kg剂量组(P0.01)。病理学检查结果显示,小肠黏膜结构不完整,绒毛出现断裂,黏膜上皮脱落。心肌纤维断裂,心肌细胞肿大,细胞核溶解、形状不规则。肝细胞排列不规则,轮廓模糊,有少量核溶解、核破裂现象,部分区域炎性细胞浸润。肾脏部分区域炎性细胞浸润,少量肾小球萎缩。结果表明,90d暴露纳米氧化锌能影响小鼠的抗氧化系统,并对小肠、肝脏、肾脏、心脏等脏器产生损伤作用。     

硝基苯致小鼠骨髓细胞的突变作用

为探讨硝基苯对哺乳动物的致突变性，将12周龄雄性昆明小鼠随机分为染毒组（26、52、104mg／kg）、空白对照组（生理盐水）、溶剂对照组（花生油）和阳性对照组（环磷酰胺），连续灌胃染毒7d，检测骨髓细胞微核率、骨髓细胞染色体畸变率以及外周血网织红细胞数。结果显示，随着染毒剂量的增加，骨髓细胞微核率、染色体畸变率均有增加，外周血网织红细胞数减少，各组与对照组差异均极显著（P〈0．01），并呈剂量-效应关系。表明，硝基苯可导致小鼠骨髓细胞发生突变。     

镉对小鼠生精细胞凋亡及bax和bcl-2基因表达的影响

将150只小鼠随机分成4个处理组和1个对照组，每组30只。给4个处理组小鼠分别一次性注射氯化镉1、2、4、6mg／kg（按体重给药），对照组小鼠注射等体积的生理盐水。于注射后第3、6和9d用原位末端标记法（TUNEL）测定睾丸内生精细胞的凋亡率，并用免疫组织化学方法检测bax和bcl-2基因的表达水平。结果显示，各染毒组小鼠的生精细胞凋亡率明显升高，与对照组相比差异显著（P〈0．05），并具有剂量-反应关系和时间-反应关系。bax基因的表达水平明显上升，而bel-2基因的表达水平明显下降。表明，镉可以诱导小鼠生精细胞凋亡，其机制可能与bax基因上调和bcl-2基因下调有关。     

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 -