对中国药典诺氟沙星对照品在不同溶媒中的稳定性研究

目的：考察不同溶媒配制的诺氟沙星对照品溶液能否保存。方法：用紫外分光光度法分别对5℃放置的使用不同溶媒的对照品溶液在0d、10d、20d、30d、40d测定最大吸收波长、吸收值。结果；以0．4％NaOH溶液为溶媒的诺氟沙星对照液于5℃放置40d，最大吸收波长、吸收值均未发生变化（无显著性差异P＞0．05）。而以pH4.0醛酸缓冲液、pH7．4磷酸盐缓冲液为溶媒的两种对照液5℃放置40d，最大吸收波长未发生变化，但吸收值明显降低（有显著性差异P＜0．05）。结论：用0．4％NaOH溶液配制的诺氟沙星对照品溶液在适宜的条件下（5℃，避光密闭）保存，40d内是稳定的，可继续使用。而用pH4．0醋酸缓冲注和pH7．4磷酸盐缓冲液配制的诺氟沙星对照品溶液则不能保存使用，必须临用新配。     

An Analysis of Chromosome on Sterility Caused by Azoospermia or Oligospermia

ＡｎＡｎａｌｙｓｉｓｏｆＣｈｒｏｍｏｓｏｍｅｏｎＳｔｅｒｉｌｉｔｙＣａｕｓｅｄｂｙＡｚｏｏｓｐｅｒｍｉａｏｒＯｌｉｇｏｓｐｅｒｍｉａ￥ＷｕＭｅｉｈｅｎｇ；ＴａｎｇＷｉｎｇｎｕｏ．（ＡＣＴＡＡＣＡＤＥＭＩＡＥＭＥＤＩＣＩＮＡＥＮＡＮＪＩＮＧ，１９９５（...     

~（99m）Tc－新半乳糖白蛋白体外受体介导结合特性的研究

本文报道￣９９ｍＴｃ－新半乳糖白蛋白（￣９９ｍＴｃ－ＮＧＡ）与大鼠肝细胞膜进行体外结合试验。结果表明：￣９９ｍＴｃ－ＮＧＡ系与肝细胞膜上的高亲和力低容量（Ｋ＿１：８．４０８９×１０￣９Ｌ／ｍｏｌ；Ｒ＿１：１．７３５０×１０￣（－１２）ｍｏｌ／ｍｇ）和低亲和力高容量（Ｋ＿２：２．０８２７×１０￣８Ｌ／ｍｏｌ；Ｒ＿２：６．９５３０×１０￣（－１２）ｍｏｌ／ｍｇ）２个结合位点相结合，其结合表现出高特异性、可饱和性及对细胞膜蛋白浓度的线性依赖性，具备受体介导结合的基本特征。￣（９９ｍ）Ｔｃ－ＮＧＡ是一个很有希望的肝受体显像剂。     

硫酸镍对红细胞毒性研究

健康小鼠腹腔注射硫酸镍10.0,5.0,2.5mg/kg,导致外周血中红细胞增高,血红蛋白不变或降低,红细胞中点彩红细胞和碱粒红细胞占有比值明显增高,网织红细胞含量升高、提示镍对外周血红细胞有毒性损害。     

Punch technique--an alternative approach to the repair of pierced earlobe deformities

The punch technique of repairing pierced earlobe deformities is a practical and simplified alternative to the usual method of repair. The procedure can easily be performed in any dermatology office since the instruments required are very basic. The technique is presented in a series of illustrations, and the results are cosmetically acceptable.     

Production and characterization of genetically engineered antibody molecules

Expression of antibody heavy- and light-chain genes by transfection permits the production of monoclonal antibodies with improved biological and antigen-binding properties. The immunoglobulin genes are placed in vectors containing a gene for encoding a protein that provides a biochemically selectable function in eukaryotic cells; these vectors are transfected into myeloma and hybridoma cells. Selection of drug-resistant cells permits the efficient isolation of the rare cells that express the transfected DNA. By placing heavy and light chains on plasmids with different selectable markers, one can deliver heavy- and light-chain genes simultaneously to the same cell. The transfected immunoglobulin genes are efficiently expressed and the proteins produced are a faithful mirror of the genes that were introduced. Using the standard techniques of genetic engineering and gene transfection, we can now produce antibodies of widely varying structures, including chimeric antibodies with segments derived from different species. These antibodies provide useful reagents to study structure-function relationships within the antibody molecule. Ultimately it will be possible to produce a new generation of antibody molecules with improved antigen-binding properties and effector functions.     

Effect of exercise on repetitive nerve stimulation studies: new appraisal of an old technique.

Repetitive nerve stimulation (RNS) is a simple and rapid method for evaluation of neuromuscular transmission defects. Although the effect of exercise in conjunction with RNS is well recognized, it has not been standardized in actual patient and control groups. In a prospective study over a period of 1 year, the authors evaluated the effect of exercise in conjunction with RNS in comparison with conventional 3-Hz RNS at rest in the clinical setting. Fifty-four patients who were referred for possible neuromuscular transmission disorders, in addition to 35 healthy control subjects, were studied. Amplitude and area decremental responses with RNS at rest and after 20 seconds of maximal exercise at 1-minute intervals up to 3 minutes were evaluated. The use of RNS with exercise resulted in additional diagnostic yield of up to 36.4% compared with conventional 3-Hz RNS at rest. The standardized use of exercise with RNS is advocated for increasing its diagnostic yield in the neurophysiologic laboratory.     

Nucleotide polymorphism in colicin E1 and Ia plasmids from natural isolates of Escherichia coli.

We examined DNA sequence polymorphism for the colicin gene clusters of seven ColE1 and six ColIa plasmids obtained from natural isolates of Escherichia coli. These gene clusters harbor levels of nucleotide diversity ranging from 0.006 (ColIa) to 0.054 (ColE1). This level of diversity is similar to that observed for chromosomally encoded E. coli genes. However, the variance associated with these estimates is severalfold higher for the plasmid-encoded genes. This increased variance may be due to the differing plasmid population sizes. The pattern of colicin gene cluster polymorphism suggests that the two colicins are evolving in different fashions. ColE1 accumulates polymorphism at an elevated rate in the central domain of the colicin protein, while ColIa polymorphism is distributed evenly along the gene cluster. Comparison of the patterns of divergence between colicin and related proteins of ColIa and Ib and patterns of polymorphism within ColIa suggest that this gene cluster is not evolving in a neutral fashion. These data lend support to the hypothesis that colicin gene clusters may evolve under the influence of diversifying selection.