品种和年龄对猪的基础免疫特性、血液皮质醇浓度及生长性能的影响

试验的目的是要证实不同品种的猪之间存在着基础免疫和生长特性的差异,这些差异是由猪的日龄不同引起的。分别选取4、8、12周龄的波克夏猪(36头)、杜洛克猪(18头)、梅山猪(54头)、长白和约克夏的杂交后代白猪(36头)、约克夏猪(36头)来进行基础免疫,血浆中的皮质醇浓度和生长性能差异的试验。所有试验猪均在17～21d之间断奶,并且转移到同样环境下的仔猪舍中待试验。试验检测指标包括:白细胞的数量和差异性、血浆中皮质醇的浓度、免疫球蛋白的浓度、吞噬细胞、嗜中性嗜菌细胞和细胞的趋化性。在所有各日龄的猪中,梅山猪的皮质醇浓度最高,而约…     

Heterogeneous and epitaxial nucleation of protein crystals on mineral surfaces

Fifty different mineral samples were tested as potential heterogeneous or epitaxial nucleants for four commonly crystallized proteins. It was found, by conventional protein crystallization techniques, that for each protein there was a set of mineral substrates that promoted nucleation of crystals at lower critical levels of supersaturation than required for spontaneous growth. Numerous examples, involving all four proteins, were observed of modification of crystal habit and, in some cases, unit cell properties promoted by the presence of the mineral nucleants. In at least one case, the growth of lysozyme on the mineral apophyllite, it was shown by lattice analysis and x-ray diffraction that the nucleation and growth of the protein crystal on the mineral was likely to involve a direct lattice match.     

Retrospective evaluation of xylazine/halothane anesthesia in 125 cattle

A retrospective morbidity and mortality study was carried out on 125 case records of cattle involving xylazine/halothane anesthesia at the Ontario Veterinary College, Guelph between May 1979 and February 1983.