The inability of tapeworm Hymenolepis diminuta and fluke Dicrocoelium dendriticum to metabolize praziquantel

Biotransformation enzymes can, to a certain extent, protect parasitic worms against the toxic effects of anthelmintics and can contribute to drug-resistance development. The objective of our work was (1) to find and identify phase I and II metabolites of the anthelmintic praziquantel (PZQ) formed by the lancet fluke (Dicrocoelium dendriticum) and the rat tapeworm (Hymenolepis diminuta) and (2) to compare PZQ metabolites in helminths with PZQ biotransformation in rat as host species. Ultra high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) was used for this purpose. During in vitro incubations, mitochondria-like and microsomes-like fractions (prepared from homogenates of adult worms or from rat liver homogenate) were incubated with 10 and 100 μM PZQ. Liquid/liquid extraction was used for samples during in vitro experiments. In the ex vivo study, living D. dendriticum and H. diminuta adults were incubated in RPMI-1640 medium in the presence of 50 nM or 100 nM PZQ for 24h. After incubation, the worms were removed from the medium and homogenized. Homogenates of worms, medium from the incubation of worms or rat hepatocytes and rat urine (collected during 24h after oral PZQ administration) were separately extracted using solid-phase extraction. The results showed that both D. dendriticum and H. diminuta enzymatic systems are not able to metabolize PZQ. On the other hand, thirty one different phase I and four phase II PZQ metabolites were detected in rat samples using UHPLC/MS/MS analyses. These results show that our experimental helminths, as the members of tapeworm and fluke groups of parasites, are not able to deactivate PZQ, and that the biotransformation enzymes of the studied helminths do not contribute to PZQ-resistance.     

The inability of a South African Babesia bovis vaccine strain to infect Boophilus microplus

A strain of Babesia bovis that had been attenuated by rapid syringe passage through a series of 23 splenectomized calves was unable to infect its vector Boophilus microplus. An attempt to transmit the attenuated Australian Babesia bigemina G strain with a South African strain of B. microplus was likewise unsuccessful. The epidemiological implication of these observations in terms of babesiosis control is discussed.     

Amaranthus retroflexus (redroot pigweed): inability to cause renal toxicosis in rabbits

Rabbits fed Amaranthus retroflexus (redroot pigweed) did not develop lesions of renal toxicosis reported in other species fed this plant. In feeding trials using adult and weanling rabbits, A retroflexus did not produce indications of renal involvement in rabbits. In both trials, treated rabbits had increased weight loss when compared with controls; however, the weight loss was not attributed to a toxic effect, but to previously described decreased palatability of Amaranthus spp.     

突发重大动物疫情应急管理工作中存在的问题和对策

2004年,高致病性禽流感在我国暴发以后,重大动物疫情应急管理工作被提到重要议事日程.县级以上人民政府都相继成立了重大动物疫情应急管理指挥机构和日常工作机构.     

无私奉献扎实工作努力为企业服务

南京水泥行业协会成立于 1 985年 1 2月 1 3日。成立初期 ,以南京地区 36家水泥企业为会员 ,历经 1 6年的发展 ,会员单位已扩大到 51家 ,包括相关的建材机械、耐磨材料、电器控制设备、科研设计、物资经营和大专院校等企事业单位 ;经济类型也由国营、地方国营和乡镇集体扩大到股份制、中外合资、外商独资和民营 ,其中民营企业占 40 % ;会员单位分布也由南京地区扩大到外省市 ,成为以水泥企业为主体的跨行业、跨所有制、跨地区的行业协会。一、认真做好信息工作 ,为企业生产经营服务根据广大企业会员的要求 ,协会秘书处从1 9 95年 3月份起 ,…     

Australian veterinarians who work with horses: attitudes to work and career

OBJECTIVE: To describe the attitudes to their work and career of those Australian veterinarians who work with horses. METHOD: Questionnaires were mailed to 866 veterinarians who had been identified as working with horses, and 87% were completed and returned. Data were entered onto Excel spreadsheets, and analysed using the SAS System for Windows. RESULTS: The main attractions of veterinary work with horses were the horses themselves and the equine industries, but working outdoors and with rewarding clients, and the satisfaction of successful outcomes were attractions for many. The list of disadvantages was longer, and included unreasonable and disagreeable clients as well as those who provided inadequate facilities, could not control their horses or did not care for them. The physical demands and risks of injury, the amount of time required, low rates of return and difficulties in collecting payment, were other major disadvantages. Some mentioned concerns about litigation, unethical behaviour, and recruiting and retaining veterinarians competent with horses. For many in mixed practice, the difficulties in affording modern equipment, and of developing and maintaining their own competence with horses, was a real concern. More than three-quarters of the respondents reported that their careers had lived up to expectations and that they would become veterinarians again; 70% of equine veterinarians would become an equine veterinarian again. Almost all (93%) of the respondents were either very glad, or 'generally glad though with some misgivings' that they had done the veterinary course. Older veterinarians reported suffering less stress, and being more content with their career, than younger colleagues. CONCLUSIONS: The advantages of doing veterinary work with horses outweigh the disadvantages for most veterinarians, especially those well advanced in their careers.     

爱心再次汇集 真情再次显现——玉树抗震救灾纪实

4月14日7时49分,青海省玉树藏族自治州玉树县发生7.1级地震,再一次揪结着每一个中华儿女的心,让所有人心中都多一份牵挂.无情的地震夺去了数以千计的生命,强烈的地震摧毁了无数的家园.昔日祥和安宁的大地,此刻却成了人间地狱,惨不忍睹.     

开展标准化工作对增强饲料企业竞争力的意义

随着改革开放步伐的加快,我国饲料工业发展迅速,加工能力、产量、产值均稳定增长,饲料产品系列化、多样化,质量不断提高,许多饲料新产品、新技术、新工艺达到国际先进水平或国内首创,科技的普及和成果转化为生产力的速度加快,饲料企业的集团化、规模化发展的步伐加快,饲料工业体系基本形成。     

我军军犬工作的摇篮

中国人民解放军北京军犬繁育训练基地是我军军犬工作的摇篮,其前身是1985年10月成立的北京军区后勤部军犬训练队.为适应新时期军事斗争的需要,1995年12月经总参谋部批准,在原来北京军区后勤部军犬训练队的基础上,正式组建为解放军北京军犬繁育训练基地.基地全面开展军犬专业的教学以及军犬繁育、疾病防治、饲料装具等科研工作,经过几代官兵的艰苦努力,现已发展成全军设施最先进、犬种最齐全、种犬数量最多的军犬繁育训练基地.她的建立,标志着我军有了集繁育、训练、教学和科研为一体的综合性军犬基地.……     

作好兽医工作应采取的几项重要措施

畜牧业具有见效快、效益高等特点,是发展农村经济的重要产业,是农作物转化增值、农民增收的重要途径,在农业经济中,具有重要地位。就产值看,我省畜牧业产值已接近农业总产值的33％。肉、蛋、奶的人均占有量也是衡量是否达到小康生活水平的重要标志。但畜牧业的发展必须建立在动物疫     

学习做好没有做过的工作

河北省建筑业协会自 1 987年成立至今 ,已历经 1 7个年头。十几年来 ,我们坚持“双向服务”宗旨 ,紧紧围绕建筑业的改革与发展开拓创新 ,扎实工作 ,积极探索在社会主义市场经济条件下协会工作思路、工作方法和办会方针 ,为企业、为政府、为行业、为市场提供多种形式的有效服务。一、坚持深入企业开展调研 ,为政府主管部门和企业提供服务为了搞好调研工作 ,体现协会在行业管理中的作用 ,我们经常主动地向业务主管单位的领导汇报工作 ,听取他们对协会工作的意见 ,了解政府主管部门每个时期的工作意图和工作重点 ,以利通过调研为政府主管部门制…