兽药使用环节存在的问题及对策

经过对兽药生产厂家和经营企业几年的整治,尤其是新<兽药管理条例>和<兽药标签和说明书管理办法>出台后,又经过GMP认证,兽药生产经营市场秩序和经营行为得到了一定的规范.但兽药使用环节中却存在诸多的问题,如:违法使用人用药品;违法使用禁用兽药;不执行休药期规定;未建立台帐等等.这些问题的存在,直接导致了动物产品的安全性问题.对此,笔者分析了兽药使用环节存在问题的原因,并对解决这些问题提出了个人观点.     

THE EFFECT OF CUTTING HEIGHT AND NITROGEN LEVEL ON THE YIELD, IN VITRO DIGESTIBILITY AND CHEMICAL COMPOSITION OF ITALIAN RYEGRASS SWARDS

Three cutting heights, 2±5, 7±6 and 12±7 cm (1, 2±5 and 5 in.) and three levels of fertilizer N, 168, 280 and 392 kg N/ha (150, 250 and 350 Ib N/ac) were imposed on a sward of Italian ryegrass (Lolium multiflorum) cv. Irish. Lowering the cutting height and increasing the level of applied N increased the yield of herhage DM. Increasing the level of applied N had a greater effect on the chemical composition of the herbage than altering the cutting height     

正交试验法优化普抗合剂制备工艺

以干浸膏得率和黄芩苷提取率为考核指标,采用正交试验法对普抗合剂水提取醇沉淀制备工艺进行考察.普抗合剂最佳制备工艺方案为加水量10倍,提取2次,每次1 h,55%的乙醇沉淀杂质 .该工艺科学合理,适合于大规模工业生产.     

Orographic enhancement of wet deposition in the United Kingdom: Continuous monitoring

Continuous monitoring of cloud and rain samples at three mountain sites in the UK has allowed consideration of the long term impact of the enhancement of the wet deposition of pollutants by orographie effects, specifically the scavenging of cap cloud droplets by rain falling from above (the seeder-feeder effects). The concentration of the major pollutant ions in the cloud water is related to the relative proximity of each site to marine and anthropogenic sources of aerosol. In general, the concentrations of major ions in precipitation at summit sites exceed those in precipitation to low ground nearby by 20% to 50%. Concentrations in orographie cloud exceed those in upwind rain by between a factor of five and ten. The results are consistent with seeder-feeder scavenging of hill cloud by falling precipitation in which the average concentration of ions in scavenged hill cloud exceed those in precipitation upwind by a factor of 1.7 to 2.3 for sulphate and nitrate respectively at Dunslair Heights and 1.5 to 1.8 for sulphate and nitrate at Holme Moss. The results suggest that the parameterisation of this relationship with scavenged feeder cloud water concentrations assumed to exceed those in seeder rain by a factor of two for the production of predictive maps of wet deposition in mountainous regions of the U.K. is satisfactory.     

Orographic enhancement of wet deposition in the United Kingdom: case studies and modelling

Two field experiments to observe the detailed response of wet deposition to orography in a polluted environment are reported. Rain events were classed as frontal, convective or mixed on the basis of meteorological data. Analysis of the deposition enhancement and cap cloud composition confirmed that for the frontal events the seeder-feeder effect (scavenging of cap cloud by rain drops) dominates. The greater concentration of ions in the water scavenged from the cap cloud than in the rain means that deposition is enhanced for all ions. For marine ions the scavenged water was found to be between five and six times as concentrated as the rain and for anthropogenically produced ions it was about twice as concentrated.A computational model of rainfall incorporating the seeder-feeder effect has been broadly successful in predicting enhancement although some details of the observed pattern remain to be explained.     

C型肉毒梭菌肉毒毒素的提取与鉴定

[目的]通过对C型肉毒梭菌肉毒毒素的提取与鉴定,为类毒素和抗毒素的制备及抗原性分析奠定基础.[方法]将分离鉴定得到的C型肉毒梭菌通过扩大培养、产毒培养后将产生的肉毒毒素采用除菌过滤、硫酸铵盐盐析、离心、透析、浓缩的方法从产毒培养基中分离提取出来.再将提取的肉毒毒素通过SDS-PAGE鉴定毒素蛋白的分子量.[结果]分离出来的毒素蛋白重链和轻链分别在98和53 KDa左右,与C型肉毒毒素的理论分子量相符.[结论]提取的肉毒毒素是C型肉毒毒素.     

Expression of Occludin in Testis and Epididymis of Wild Rabbits, Lepus sinensis coreanus

Tight junctions (TJs) in inter-Sertoli junctional areas and epididymal epithelia build up the blood–testis barrier (BTB) and the blood–epididymal barrier (BEB), respectively. In this study, the expression of occludin, an integral member of the TJs, was examined in testis and different regions of epididymis of Lepus sinensis coreanus , an Korean wild rabbit species. In testis, intense occludin immunoreactivity was found in the basally located inter-Sertoli junctional area together with diffused immunoreactivity of occludin in the cytoplasm of Sertoli cells. It can be suggested that occludin is one of the robust elements of BTB in seminiferous tubules of rabbit testis. In proximal and distal caput epididymis, occludin immunoreactivity was found in the lateral as well as apical contacts of epithelial cells. In corpus epididymis, intense occludin immunoreactivity was found in the basolateral as well as apical contacts of epithelial cells together with cytoplasmic signal. In cauda epididymis, occludin immunoreactivity in luminal epithelia was relatively strong but largely found in the cytoplasm. This suggests that intriguing regulatory mechanisms differentially recruit occludin to the TJ in the different regions of epididymal epithelia. The differences in the subcellular localization as well as expression levels of occludin among the epididymal segments may reflect differential paracellular permeability of epithelia along the epididymal tubules and be correlated with sperm maturation in rabbit. In Western blot, a major form of occludin was MW 62 kDa together with small fragments of MW 34–39 kDa in testis and epididymis, suggesting the peptide cleavage of occludin. This is the first report on the molecular nature of TJs in a wild rabbit testis and epididymis.     

Further studies on the anticancer activity of citrus limonoids

Research in this laboratory has shown that some citrus limonoids can inhibit the development of 7,12-dimethylbenz[a]anthracene-induced oral tumors. The data from these studies have suggested that certain rings in the limonoid nucleus may be critical to antineoplastic activity. Using the hamster cheek pouch model, three new limonoids (ichangensin, deoxylimonin, and obacunone) have now been tested for cancer chemopreventive activity. In the first experiment, it was found that the treatments with ichangensin had no effect on tumor number or burden. In the second experiment, obacunone reduced tumor number and burden by 25 and 40%, respectively, whereas deoxylimonin reduced tumor number and burden by 30 and 50%, respectively. The results with deoxylimonin were significant, p < 0.05. Overall, the data indicated that changes in the A ring of the limonoid nucleus can lead to a loss of anticancer activity, whereas changes in the D ring can be tolerated without any apparent loss of biological activity.