镉对大鼠原代肝细胞的毒性损伤

用两步灌流法获得大鼠肝细胞,肝细胞暴露于浓度为2.5、5、10μmol/L的醋酸镉24 h.测定了细胞活力、培养上清液中乳酸脱氢酶(LDH)、天冬氨酸转氨酶(AST)和丙氨酸转氨酶(ALT)活性及细胞内谷胱甘肽过氧化物酶(GSH-PX)活性、还原型谷胱甘肽(GSH)和丙二醛(MDA)含量的变化.结果表明,细胞相对存活率显著下降(P<0.01),LDH、AST和ALT的释放量增加,5μmol/L和10 μmol/L剂量组与对照组相比差异均显著(P<0.01),细胞内GSH-PX活性降低,各剂量染毒组与对照组相比,差异均极显著(P<0.01);细胞内GSH含量升高,5 μmol/L和10μmol/L剂量组与对照组差异均显著(P<0.05),细胞内MDA含量升高,10μmol/L剂量组与对照组相比差异显著(P<0.05).表明镉可致肝细胞损伤,并且氧化应激起了重要作用.     

镉对大鼠大脑皮质神经细胞的氧化损伤及N-乙酰半胱氨酸的保护效应

为研究镉对新生大鼠原代大脑皮质神经细胞的脂质过氧化损伤及N-乙酰半胱氨酸(N-acetyl cysteine,NAC)的保护效应,对神经细胞用不同浓度(0,5、10、20 μmol/L)醋酸镉染毒和NAC(100 μmol/L)进行保护,检测细胞内活性氧(ROS)水平、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氩酶(CAT)活性及丙二醛(MDA)含量.结果表明,与时照组比较,染毒组细胞内ROS水平、MDA含量和CAT活性极显著升高(P＜0.01),GSH-Px活性降低,20μmol/L组出现显著差异(P＜0.05);NAC保护组与相应染毒组比较,ROS水平、MDA含量和CAT活性呈不同程度降低,部分组间出现显著差异(P＜0.05);说明镉有促进神经细胞脂质过氧化的作用,NAC可提高神经细胞的抗氧化能力,对镉暴露所致的脂质过氧化损伤有一定的保护作用.     

莱菔硫烷对染镉小鼠睾丸间质细胞抗氧化功能影响的研究

试验旨在研究莱菔硫烷（SFN）对染镉（Cd）小鼠睾丸间质细胞（TM3细胞）抗氧化应激能力的影响。向TM3细胞培养液中添加Cd和SFN,分别测定Cd的半数抑制浓度（IC₅₀）和SFN的安全剂量范围,建立试验模型,通过检测TM3细胞的相对存活率、乳酸脱氢酶（LDH）活性及细胞抗氧化水平,判定SFN对Cd诱导TM3细胞毒性的影响。结果显示：①随着Cd浓度的增加,TM3细胞的相对存活率降低,Cd对体外培养TM3细胞的IC₅₀为51.4 μmol/L;SFN在一定范围内对细胞存活有促进作用,但超过范围后具有毒性,且浓度越大毒性越大,本试验条件下选择SFN浓度为2.5、5和10 μmol/L。②与对照组相比,Cd组TM3细胞的T-SOD、GSH-Px活性及GSH含量显著或极显著降低（P < 0.05;P < 0.01）,LDH活性、MDA含量升高;SFN组LDH活性、MDA含量降低,GSH含量、T-SOD活性及GSH-Px活力升高;与Cd组相比,Cd＋SFN组GSH含量、T-SOD活性及GSH-Px活力显著或极显著升高（P < 0.05;P < 0.01）;LDH活性、MDA含量则降低,表明SFN具有缓解染Cd诱导TM3细胞毒性的作用。     

灌胃染镉对大鼠体内某些酶的影响及镉的器官分布

30只成年雌性SD大鼠，等分为5组，Ⅰ至Ⅳ组灌胃馀服分别含0、0.2、1.0、2.0mg镉（Cd）的氯化镉溶液1mL／只，每日1次，持续10d；Ⅴ组灌镉剂量与Ⅳ组相同，持续时间为30d。结果发现，染镉组（Ⅱ－Ⅳ组）：血浆丙氨酸氨基转移酶（ALT）和精氨酸酶（ARG）活力明显升高（P＜0.05），但ALT活力升高剂量－效在系不规律；肝匀浆ALT活力明显下降（P＜0.05或P＜0.01）；全血谷胱甘肽过氧化物酶（GSH－Px）活力显著下降（P＜0.05），肝匀浆中GSH－Px的活力也下降；心、肝、肾中Cd的含量无意产加，蓄积量与灌服剂量呈正相关（r值分别为0.9384、0.9687和0.9379）。Ⅳ组和Ⅴ组比较，随时间延长，心、肝、肾中Cd蓄积量均明显增加，且肾较肝增加更显著，结论认为，灌胃染镉对大鼠的生长有障碍作用，镉可以明显地抑制SH－Px的活力，降低机体组织的抗氧化能力，引起肝等实质细胞的损伤；血浆ARG的活力可以作为哺乳动物急性镉暴露的一个辅助性监测指标；由于损伤性泄漏和直接的抑制同时存在，以血浆中ALT的活力来评价镉对实质器官的损害应十分慎重。     

乐果对大鼠原代培养肝细胞的毒性试验

通过给大鼠肝细胞培养液中加入乐果(染毒终浓度分别为0,3,30和300μmol/L)染毒,MTT法测定乐果对肝细胞增殖的影响,同时测定肝细胞培养液中乳酸脱氢酶(LDH)及细胞内谷胱甘肽(GSH)的含量,研究了乐果对原代培养大鼠肝细胞的毒性作用。结果显示,与对照组相比,乐果对原代培养肝细胞增殖有明显的抑制作用,且呈剂量-时间效应关系。染毒后48 h细胞生长达高峰时,细胞活率分别为对照组的97%、82%和75%;300μmol/L染毒组细胞染毒后24 h、36 h、48 h、60 h和72 h细胞活率分别为对照组的67%、82%、75%、71%和63%。同时,乐果染毒12 h和24 h后各染毒组培养液上清中LDH含量均极显著升高(P<0.01),尤其是300μmol/L染毒组12 h和24 h培养液上清中LDH含量分别为对照组的7.35倍和8.75倍;同一剂量组随着染毒时间延长,LDH含量呈上升趋势。染毒12 h和24 h后30μmol/L及300μmol/L组细胞内GSH含量均存在极显著差异(P<0.01);同一剂量组随着染毒时间延长,GSH含量呈下降趋势。表明乐果对肝细胞有直接的毒性作用,能够抑制其增殖,引起细胞膜脂质过氧化损伤。     

黄芩素对镉致大鼠肝脏损伤的保护作用研究

为了研究黄芩素对镉致大鼠肝脏损伤的保护作用,试验将20只雄性SD大鼠随机分为对照组、黄芩素组、镉组、镉+黄芩素组,各组每天分别灌服生理盐水、黄芩素、氯化镉、氯化镉+黄芩素。6周后处死大鼠,采集血清和肝脏,检测血清中天冬氨酸转氨酶(AST)和丙氨酸转氨酶(ALT)活性,肝脏组织中丙二醛(MDA)和还原型谷胱甘肽(GSH)含量。结果表明:镉可极显著提高AST、ALT活性(P0.01),显著升高MDA和降低GSH含量(P0.05);黄芩素能显著降低镉组AST、ALT活性(P0.05),显著降低MDA和升高GSH含量(P0.05)。说明镉可导致大鼠肝脏组织脂质过氧化损伤,黄芩素对镉导致的损伤具有保护效应。     

茵陈水提物对镉中毒所致小鼠肝氧化应激的保护作用

目的:观察茵陈水提物对镉中毒所致小鼠肝脏氧化应激的保护作用。方法:将实验小鼠随机分为对照组,镉中毒组,茵陈水提物高、低剂量组。镉中毒组采用饮水染毒(氯化镉浓度为50 mg/L),茵陈水提物高、低剂量组(40 m L/kg、20 m L/kg)均以灌胃给药,1次/d,30 d后采样检测小鼠血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)的活力以及肝组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽(GSH)活力和丙二醛(MDA)含量。结果:茵陈水提物可明显降低镉中毒小鼠血清中ALT和AST活力,增强镉中毒小鼠肝组织中SOD、GSH-Px、GSH的活力,并降低MDA含量。结论:茵陈水提物可抑制镉中毒所致小鼠肝脏的氧化应激,对镉中毒所致小鼠肝损伤有保护作用。     

湿生扁蕾乙酸乙酯提取物对乙醇诱导L02细胞氧化损伤的保护作用研究

研究湿生扁蕾乙酸乙酯提取物(GEE)对乙醇诱导人正常肝细胞(L02)氧化损伤的保护作用及其机制。用400μmol/L乙醇诱导L02细胞建立体外细胞氧化损伤模型,加入GEE 25μg/mL、50μg/mL、100μg/mL作用24 h,采用MTT法检测细胞存活率;检测细胞培养上清液中谷丙转氨酶(ALT)、谷草转氨酶(AST)、细胞内超氧化物歧化酶(SOD)和丙二醛(MDA)含量的变化;DCFH-DA探针染色流式细胞仪检测细胞内ROS水平;DTNB-GR动力学循环法检测胞内还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)的含量变化。结果表明,400μg/mL乙醇诱导L02细胞24 h可建立肝细胞氧化损伤模型。GEE在25～100μg/mL对L02细胞无损伤。与模型组比较,GEE中剂量、高剂量组能显著提高L02细胞存活率(P0.001);降低细胞上清液中ALT、AST含量(P0.001);使细胞内SOD活力显著提高(P0.001);MDA含量明显降低(P0.001);同时使细胞内ROS水平降低(P0.01)、GSH/GSSG比值提高(P0.001)。提示GEE对乙醇诱导的L02细胞损伤具有保护作用,其机制可能与其减轻氧化应激反应有关。     

白藜芦醇对甲基乙二醛损伤BRL-3A细胞的抑制作用

为研究甲基乙二醛(MGO)对大鼠肝细胞BRL-3A细胞的损伤机制,在MGO存在的情况下,以50μmol/L白藜芦醇处理BRL-3A,分别用MTT法检测细胞活力;DNPH法检测细胞内Schiff base浓度;DCFH-DA荧光探针法检测ROS水平;以及脂质过氧化产物MDA含量的检测。结果表明,MGO导致细胞内Schiff base、ROS和MDA显著增加,诱导细胞发生氧化应激,白藜芦醇处理可有效改善MGO对细胞的损伤作用。     

铅和（或）镉对大鼠肾细胞的毒性损伤及硒的拮抗作用

为探讨铅和（或）镉的毒性机制及硒的拮抗作用,在大鼠肾细胞培养过程中添加不同浓度的铅、镉和硒,在显微镜下观察细胞形态,测定细胞凋亡率和细胞周期及上清液脂质过氧化指标。结果表明：（1）20μmol/L以上铅、镉单独染毒组细胞损伤严重,加硒后细胞的形态损伤有降低的趋势;（2）铅、镉单独和联合染毒组GSH-Px、SOD活性随染毒剂量的增加,呈逐渐下降趋势（P〈0.05）,而MDA含量和细胞凋亡率则呈升高趋势（P〈0.05）,具有明显的剂量-效应关系和剂量-时间关系;（3）在铅、镉单独和联合染毒组加硒,脂质过氧化指标呈下降趋势（P〈0.05）,说明硒对铅、镉及其联合暴露所致的脂质过氧化损伤有一定的保护作用（P〈0.05）。     

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.     

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 -