苏云金芽胞杆菌晶体毒素对体外培养的日本血吸虫童虫的作用

将感染日本血吸虫的钉螺常规逸蚴，经注射器推压机械断尾获得的童虫，加入内含１０％兔血清的ＲＰＭＩ－１６４０培养液后，置于单克隆培养板内，以苏云金芽胞杆菌（菌株ＹＢＴ－１９５５）制得的伴胞晶体毒素，以不同的浓度加入以上各孔中于３７℃，５％ＣＯ２培养箱内培养。培养１２ｈ后发现童虫活动力减弱，有些已经死亡；２４ｈ后，随着加入伴胞晶体毒素浓度的增加，童虫死亡率也相应增加，呈正相关（ｒ＝０．８９７）。经毒素蛋白含量为４０ｍｇ／Ｌ处理的童虫，２４ｈ后死亡率为１００％，ＬＤ５０为１５．９５μｇ（１ｍＬ）。     

低功率氦氖激光加血卟啉衍生物杀伤肿瘤细胞的超微结构研究

用低功率氦氖激光-血卟啉衍生物(HpD)所产生的光动力学(PDT)效应治疗小鼠S180纤维肉瘤已获得了一定的实验性疗效,在此基础上进行了PDT杀伤肿瘤细胞的超微结构研究。电镜观察结果发现:PDT疗法治疗后第1天,肿瘤细胞线粒体肿胀,有的线粒体的嵴断裂;第3天,线粒体基质聚集而出现空化灶,嵴消失,内质网扩张,微绒毛减少;治疗后第7天,线粒体基质溶解呈空泡化,细胞膜破坏,胞浆内有空泡,可见胞浆内容物溢出胞外,核糖体减少,核膜部分破坏,染色质聚集成团,核膜破坏消失;13天,细胞核溶解,核内容物溢出胞外。     

实验性犬传染性肝炎肝胆的扫描电镜和透射电镜观察

透射电镜下,犬传染性肝炎急性坏死型病例肝细胞线粒体高度肿胀,嵴断裂。病变严重的,肝细胞胞浆固有结构崩解、碎裂。核内包涵体由基质和ICHV粒子构成;在不含包涵体的核内也见到ICHV粒子。核内的ICHV粒子通过溶解的核膜或由于核崩解而释入胞浆;当细胞膜局部破裂或整个细胞崩解时,细胞内的ICHV粒子释放于细胞外。在嗜酸性小体的胞浆内观察到ICHV粒子。窦状隙内皮细胞和星状细胞呈现与肝细胞类似的变化。扫描电镜下,组织学呈凝固性坏死的胆囊粘膜袁面平坦无结构;亦见胆囊粘膜有局部灶坏死,与周围界限明显,坏死灶外围的上皮细胞结结构不整,上皮顶部凸出的颗粒大小不一或脱落。透射电镜下,呈坏死的胆囊粘膜上皮细胞固有结构消失,呈均质状;其余部位的上皮细胞微绒毛断裂、脱落;线粒体肿胀,嵴溶解,上皮顶部堆集大量的致密小体,细胞间连接复合体结构消失;亦见血管均质坏死,血管内皮的坏死与粘膜上皮的坏死同步或先于其发生。     

日本血吸虫童虫冷冻保藏复苏后生活史循环的研究

本文报告了日本血吸虫童虫经液氮冻藏复苏后的生活史循环的情况。童虫冻藏３６天和５０天后腹腔注射感染小鼠，亲代成虫回收率为９．０和８．９％。感染鼠肝内的子代虫卵孵出的子１代毛蚴感染钉螺，感染率为５９和６７％；平均每个钉螺第１次逸出的子１代尾蚴数为８００～９００条。子１代尾蚴感染小鼠后，其子１代成虫回收率为５５和５６％。合抱雌、雄成虫的体长、性腺的发育和虫体对宿主的致病力与正常途径感染者无明显差异。     

日本血吸虫信号转导蛋白sjwnt10a基因的克隆及其在童虫和成虫中mRNA表达量的变化

利用RACE技术从19日龄的日本血吸虫童虫中扩增了1个Wnt家族基因，并对其进行了生物信息学分析。同源性分析表明，该基因为日本血吸虫新基因，完整开放阅读框（ORF）长1896bp，编码631个氨基酸，理论分子质量为73．3ku。该基因编码的氨基酸序列具有wnt家族蛋白的典型特征，与人、鼠Wnt10a的氨基酸序列同源性均为26％，推测为血吸虫的Wnt10a基因，命名为Sjwnt10a（GenBanK登录号DQ643829）。利用实时荧光定量PCR分析该基因在日本血吸虫不同发育阶段虫体中的表达情况，结果显示该基因在19日龄的日本血吸虫童虫中表达量最高，在14日龄童虫和44日龄雄虫中也有表达，但分别仅为19日龄童虫表达量的8．8％和5．0％，而在31日龄成虫和44日龄雌虫中没有检测到该基因。结果提示，童虫差异表达的Sjwnt10a基因可能对童虫的生长、发育至关重要。     

实验性奶山羊缺硒病骨骼肌的超微结构研究

实验性缺硒病奶山羊骨骼肌经电子显微镜观察,见有明显的超微病变。肌质膜破裂,肌原纤维溶解断裂;纵管系统(SR)、横管系统(TS)变位,三联体破坏;线粒体肿胀、变形,内部膜溶解,嵴断裂,基质电子密度不均匀,有大块空白区。其中有中等电子密度团块,被单膜包围;肌核膜双层结构不清,局部溶解,染色质外溢。细胞器生物膜损伤。以线粒体损害最为重笃。     

IgM单抗体内,外杀伤日本血吸虫的研究

本文报道应用急性感染日本血吸虫的Ｂａ１ｂ／ｃ小鼠脾细胞和ＳＰ２／０骨髓瘤细胞融合，获得了一株具有抗血吸虫攻击感染保护作用的ＩｇＭ单抗ｓｓｊ１４。在被动免疫转移试验中，这株单抗在小鼠体内提供了２７．６９％～６８．５％的减虫率。体外ＡＤＣＣ试验显示该单抗参与了巨噬细胞和嗜酸性粒细胞介导的杀伤血吸虫童虫的作用，免疫化学特性测定表明该单抗同时对血吸虫尾蚴、成虫和虫卵三期虫体抗原起反应，靶抗原的分子量为２９０ＫＤ，分别位于血吸虫童虫和成虫的表膜及虫卵的卵壳。靶抗原表位的化学性质为多糖类，它同时被辐照致弱尾蚴免疫的大鼠血清、血吸虫慢性感染人血清和小鼠血清所识别。本文结果表明，ＩｇＭ抗体和多糖类抗原在血吸虫病免疫保护作用中发挥了重要的作用。     

维生素E缺乏对鲤骨骼肌损伤的影响

本文旨在探讨VE缺乏对鲤骨骼肌损伤的形态学影响。在半纯合日粮中分别添加0、25、50和100 mg/kg的VE,投喂体重约60 g的鲤鱼20周。结果表明:鲤鱼摄入VE缺乏的饲料后,出现“瘦背症”、脊柱弯曲及以突眼、竖鳞和腹水为特征的渗出性素质样病变。病理剖解见体壁肌肉萎缩,特别是背部两侧肌肉萎缩变薄,其厚度仅为对照组的1/4~1/2,似刀刃状;体侧红肌纤维褪色变白,呈白肌肉外观。组织学变化主要表现为肌营养性不良,骨骼肌变性、坏死,淋巴细胞和单核细胞浸润,大量结缔组织增生,残存的肌纤维萎缩变细。超微结构上表现为骨骼肌细胞核膜间隙增宽,呈锯齿状,并发生局部或广泛性的断裂,核变形,电子密度降低;肌浆内糖原颗粒明显减少,线粒体肿胀,嵴断裂,甚至溶解呈空囊泡状,肌原纤维的横纹模糊不清或完全消失。结论:日粮中0、25和50 mg/kgVE水平会导致鲤出现VE缺乏症,其骨骼肌主要表现为变性、坏死、肌萎缩和炎症细胞浸润的肌营养性不良。     

口服抗原疫苗预防小鼠日本血吸虫病的初步试验

为了观察口服可溶性血吸虫成虫抗原疫苗预防小鼠日本血吸虫病的效果，本试验应用生物可降解的天然高分子材料──壳聚糖作为载体[1，2]，运用单凝聚法[4]制成粒径500～1500μm的可溶性血吸虫成虫抗原微囊，胃饲ICR小鼠，经3次免疫后人工感染日本血吸虫，4周后剖杀小鼠。结果，试验组获得43．23％（P＜0．05）减虫率和41．18％（P＞0．05）减雌率。血吸虫抗原微囊体外释放试验表明，在0．01MolpH7．2PBS中微囊4h后即开始释放抗原，至第7天时抗原释放结束，累积释放抗原95．87％。     

中华真地鳖几丁质含量的研究初报

以中华真地鳖全虫、体壁、蜕和刚蜕皮的雌成虫为原料,利用消化法测得其几丁质含量分别为 11.50％、12.99％、11.02％和3.15％,并简要分析了蜕的开发利用及几丁质争地鳖虫药理作用的关系。     

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