The determination at housing of exposure to gastrointestinal nematode infections in first-grazing season calves

Various parameter estimates were assessed at housing in calves that had been exposed to gastrointestinal nematodes during a first grazing season. The analysis involved 41 groups of first grazing season (FGS) calves on 15 different farms in Belgium and comprised groups that had received chemoprophylactic treatment and untreated controls. Serum pepsinogen levels gave the clearest division between chemoprophylactic-treated calf groups (all were <2.6 U tyr), and untreated calf groups in which sub-clinical (range: 2.0–4.1 U tyr) and clinical infections (range 3.7–6.3 U tyr) occurred. There was also a tight relationship between individual pepsinogen values and adult Ostertagia burdens obtained at slaughter. In chemoprophylactic-treated groups there was a significant negative relationship between mean serum pepsinogen levels at housing and the proportion of the grazing season covered by different chemoprophylactic systems. Although only limited data on crude adult Ostertagia antigen ELISA were available, a good relationship between optical densities and estimated exposure was also found. The parasitological parameters, faecal egg counts and pasture Ostertagia larval counts at housing, and weight gain per day, gave less clear divisions among the three categories (chemoprophylaxis, sub-clinical and clinical). Distinguishing how much exposure a calf group has experienced during a first grazing season could help in designing more appropriate control measures for the FGS calves in the next year, assuring good protection and at the same time allowing sufficient exposure for the development of acquired immunity to Ostertagia, and for this serum pepsinogen is recommended.     

阿苯达唑和奥芬达唑对猪体内囊尾蚴作用酶组织化学观察

目的　采用酶组织化学技术半定量观察阿苯达唑和奥芬达唑对猪体内囊尾蚴发育过程中乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、谷氨酸脱氢酶(GDH)、三磷酸腺苷酶(ATPase)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、6-磷酸葡萄糖酶(G6Pase)、黄嘌呤氧化酶(XOD)、脂酶(FE)活性变化的影响。方法　以用药组与不用药对照组猪体内囊尾蚴周围肌组织冰冻切片测各种酶的活性。结果　表明阿苯达唑和奥芬达唑作用后,各种酶活性均出现显著性升高,随后逐渐降低。结论　揭示药物作用后,由于虫体能量代谢障碍,导致物质分解代谢和物质转运代谢代偿性增强,随后由于代谢体系被破坏而酶活性逐渐降低。     

Oxfendazole treatment of non-parasitized lambs and its effect on the immune system

Ten parasite-free lambs were drenched with oxfendazole on days 0 and 28 and, one day after each drench, were injected with human erythrocytes and ovalbumin. Ten other antigen-injected lambs were not drenched (controls). Lymphocytes collected 3 days after each antigen injection and cultured in RPMI 1640 plus 5% fetal calf serum (FCS) and lymphocytes collected 3 days after the first and 3 and 7 days after the second antigen injection and cultured in 50% autologous serum had decreased blastogenic activity compared with control lymphocytes. After the second drench, decreased blastogenesis was seen with lymphocytes collected on days 3 and 7 and cultured in 5% FCS and concanavalin A (Con A) and on day 3 when cultured in 5% FCS and phytohaemagglutinin (PHA). Decreased blastogenesis was also seen with lymphocytes collected 7 and 29 days after the second injection of antigen and cultured in 50% autologous serum plus Con A and on days 3, 7 and 29 when cultured in 50% autologous serum and PHA.Significantly depressed antibody responses to both antigens were seen after the second drench. The serum complement level was depressed 3 days after the second injection of antigen. Serum nitric oxide levels were significantly depressed 3 and 21 days after the first and 7 and 21 days after the second injection of antigen. There were no differences in levels of growth-promoting hormones but the drenched lambs gained significantly more weight than the controls.Abbreviations C complement - Con A concanavalin A - cpm counts per minute - EIA enzyme immunoassay - FCS fetal calf serum - IGF insulin-like growth factor - oIGF-1 ovine insulin-like growth factor-1 - PBS phosphate-buffered saline - PHA phytohaemagglutinin     

高效液相色谱法测定奥芬达唑原料中的有关物质

用高效液相色谱法测定奥芬达唑原料中的有关物质,色谱柱为C 18柱,流动相为乙腈-2 g/L戊烷磺酸钠溶液(36∶ 64,V/V),用2.8%(V/V)的硫酸溶液调节pH值至2.7.流速为1 mL/min,检测波长为 254 nm.     

The uptake of fenbendazole by cattle and buffalo following long-term low-level administration in urea-molasses blocks: Further studies on block formulations

Fenbendazole (Hoechst India Ltd.) was incorporated at 0.5 g/kg into urea molasses blocks made by two different processes. The proportion of the drug remaining in the blocks and the plasma concentrations of the parent compound and its metabolites were measured. Recovery of the drug in blocks made by the cold and the modified hot processes was 90% and 96%, respectively. The plasma metabolite profile revealed a plateau between days 4 and 6 of feeding in cattle and buffalo. However, the plasma concentrations of fenbendazole and its metabolites were low in buffalo compared to cattle.Abbreviations HPLC high-performance liquid chromatography - MUMB medicated urea molasses blocks - UMB urea-molasses block     

奥芬哒唑对人工感染脑多头蚴绵羊的早期治疗试验

为了寻找一种治疗脑多头蚴早期感染的新药物，应用奥芬哒唑（Oxfendazole)于感染后第8d和第15d以30mg/kg的剂量，对人工感染脑多头蚴的绵羊进行了单剂量和三剂量早期治疗试验。结果表明：无论是第8d还是第15d，三剂量组对人工接种早期感染脑多头蚴的绵羊具有完全的治疗作用。奥芬哒唑是治疗羊脑多头病的理想药物。     

Influence of subclinical nematodosis on the kinetic disposition of fenbendazole in buffaloes

The disposition kinetics of fenbendazole was studied in buffaloes subclinically infected with gastrointestinal nematodes. There was significantly reduced uptake of the drug in infected animals compared to uninfected controls. The pH of the duodenal liquor was highly alkaline compared to the acidic pH in uninfected animals. The egg count in the faeces never became zero though the numbers were reduced to a great extent compared to pre-treatment values. The influence of the host's physiology on the reduced bioavailability of fenbendazole is discussed.Abbreviations AUC area under the concentration-time curve - C _max peak concentration in plasma; - e.p.g. eggs per gram of faeces - ETH-OFZ ethyl oxfendazole - FBZ fenbendazole - FBZ-SO₂ fenbendazole sulphone - FEC faecal egg count - HPLC high-performance liquid chromatography - OFZ oxfendazole - T _1/2 half-life in plasma - T _max time to peak concentration in plasma     

Enantiomeric behaviour of albendazole and fenbendazole sulfoxides in domestic animals: Pharmacological implications

Albendazole and fenbendazole are methylcarbamate benzimidazole anthelmintics extensively used to control gastrointestinal parasites in domestic animals. These parent compounds are metabolised to albendazole sulfoxide and fenbendazole sulfoxide (oxfendazole), respectively. Both sulfoxide derivatives are anthelmintically active and are manufactured for use in animals. They metabolites have an asymmetric centre on their chemical structures and two enantiomeric forms of each sulfoxide have been identified in plasma, tissues of parasite location and within target helminths. Both the flavin-monooxygenase and cytochrome P450 systems are involved in the enantioselective biotransformation of these anthelmintic compounds in ruminant species. A relevant progress on the understanding of the relationship among enantioselective metabolism and systemic availability of each enantiomeric form has been achieved. This article reviews the current knowledge on the pharmacological implications of the enantiomeric behaviour of albendazole sulfoxide and oxfendazole in domestic animals.