Visceral leishmaniasis in the German shepherd dog. I. Infection, clinical disease, and clinical pathology

Two groups of three German shepherd dogs each were inoculated with Leishmania chagasi or Leishmania donovani amastigotes and the infection was followed for 82 days. The dogs developed a persistent infection, became thin, and developed splenomegaly and lymphadenomegaly by 55 days after inoculation. All dogs developed a normocytic, normochromic anemia of increasing severity. Thrombocytopenia and leukopenia occasionally occurred. Blood tryptophan levels were decreased significantly in infected dogs. Increased total serum protein, with hypergammaglobulinemia and hypoalbuminemia, was present in all dogs to various degrees. There was a marked increase in gamma globulins, with smaller increases in alpha and beta globulins. Many of the clinicopathologic changes observed in these dogs were similar to the disease as it occurs in man. The German shepherd dog may be a useful laboratory model for the study of visceral leishmaniasis.     

高效液相色谱仪期间核查方法研究

高效液相色谱仪做为强制检定仪器除按规定定期送法定检定机构进行检定外,在两次检定周期之间还需对使用频率高的仪器进行期间核查以维持设备校准状态的可信度.本文简述了期间核查的项目和方法,包括外观检查、输液系统检查、色谱柱和检测器性能检查及做好检查和处理结果的记录.     

中西医结合治疗羊传染性脓疱

2004年10月27日,我县王甫乡一养羊户的羊只发生以唇部皮肤呈菜花样增生、出血、溃烂为特征的疫病,畜主称之为"烂嘴病",该病传播快,发病率高,给养羊户造成严重的经济损失.笔者根据流行病学调查、临床症状诊断为羊传染性脓疱,采用中西医结合治疗,收到了较好的疗效.     

Scintigraphy of normal mouse ovaries with monoclonal antibodies to ZP-2, the major zona pellucida protein

The zona pellucida is an extracellular glycocalyx, made of three sulfated glycoproteins, that surrounds mammalian oocytes. Parenterally administered monoclonal antibodies specific for ZP-2, the most abundant zona protein, localize in the zona pellucida. When labeled with iodine-125, these monoclonal antibodies demonstrate a remarkably high target-to-nontarget tissue ratio and provide clear external radioimaging of ovarian tissue.     

Evolution of a microbial acetyltransferase for modification of glyphosate: a novel tolerance strategy

N-Acetylation is a modification of glyphosate that could potentially be used in transgenic crops, given a suitable acetyltransferase. Weak enzymatic activity (k(cat) = 5 min(-1), K(M) = 1 mM) for N-acetylation of glyphosate was discovered in several strains of Bacillus licheniformis (Weigmann) Chester by screening a microbial collection with a mass spectrometric assay. The parental enzyme conferred no tolerance to glyphosate in any host when expressed as a transgene. Eleven iterations of DNA shuffling resulted in a 7000-fold improvement in catalytic efficiency (k(cat)/K(M)), sufficient for conferring robust tolerance to field rates of glyphosate in transgenic tobacco and maize. In terms of k(cat)/K(M), the native enzyme exhibited weak activity (4-450% of that with glyphosate) with seven of the common amino acids. Evolution of the enzyme towards an improved k(cat)/K(M) for glyphosate resulted in increased activity toward aspartate (40-fold improved k(cat)), but activity with serine and phosphoserine almost completely vanished. No activity was observed among a broad sampling of nucleotides and antibiotics. Improved catalysis with glyphosate coincided with increased thermal stability.