Optimization of plasmid maintenance in the attenuated live vector vaccine strain Salmonella typhi CVD 908-htrA

The broad objective of the research presented here is to develop a noncatalytic plasmid maintenance system for the stabilization of multicopy expression plasmids encoding foreign antigens in a Salmonella typhi live-vector vaccine strain such as CVD 908-htrA. We have enhanced the maintenance of expression plasmids at two independent levels. First, we removed dependence upon balanced-lethal maintenance systems that involve catalytic enzymes expressed from multicopy plasmids; we accomplished this through incorporation into expression plasmids of a postsegregational killing system based on the noncatalytic hok-sok plasmid addiction system from the antibiotic resistance factor pR1. We also included at least one naturally occurring plasmid partition function in our expression plasmids, which eliminates random segregation of these plasmids, thereby enhancing their inheritance and stability; to accomplish this, we incorporated either the par locus from pSC101, the parA locus from pR1, or both. We monitored the stability of optimized expression plasmids within CVD 908-htrA by quantitating expression of a variant of green fluorescent protein (GFPuv) by using flow cytometry. In this report, we demonstrate the utility of this novel plasmid maintenance system in enhancing the stability of our expression plasmids and go on to show that as the copy number of stabilized plasmids increases, the toxicity of GFPuv synthesis also increases. The implications of these observations for the rational design of immunogenic and protective bacterial live vector vaccines are discussed.     

人和大鼠腰椎关节突关节的SP能神经纤维的分布

目的：证实支配腰椎关节突关节的神经支配和化学性质，方法：用逆行荧光素标记结合免疫组化法，研究７只大鼠腰部脊神经节细胞的周围突分支投射到腰椎关节突关节及其递质性质以及３例人腰椎关节突关节囊上神经末梢的化学性质，结果：发现大鼠一侧Ｌ５和Ｌ６之间的关节突关节受同侧Ｌ２－５节段的脊神经节的部分细胞周围突分支支配，其中有３３．３９９％的中型和小型细胞为中ＳＰ能免疫反应阳性，人的关节突关节囊含有ＳＰ阳性的神经     

Epidemiology of group C rotavirus infection in Western New York women of childbearing age.

Umbilical cord serum samples (380), an average of 10 per month for 3 years (1990 to 1992), were tested by indirect immunofluorescence assay for group C rotavirus immunoglobulin G. Thirty percent were positive, suggesting that approximately one-third of women of childbearing age in western New York have experienced group C rotavirus infection.     

增殖细胞核抗原表达与AgNORs图像分析在判断肺癌预后上的应用

应用抗增殖细胞核抗原（抗ＰＣＮＡ）单克隆抗体，采用Ｓ－Ｐ免疫组化方法和ＡｇＮＯＲｓ染色图像分析，对有确切随访结果的８６例原发性肺癌和１０例肺炎性假瘤进行了研究。结果表明：经ＰＣ－ＮＡ阳性反应计算出的增殖指数（ＰＩ）与图像分析的ＡｇＮＯＲｓ计数及其颗粒总面积间存在着明显的相关性。二者均与肺癌分型有关，并随癌分化程度的增高而减小；与ＴＮＭ分期中的淋巴结（Ｎ）和远隔转移（Ｍ）有关；术后存活５年以上者明显小于３年以内者（Ｐ＜０．０１）。认为ＰＣＮＡ的表达和ＡｇＮＯＲｓ图像分析技术有助于肺癌的分型、分化及预后的判断。     

针刺对实验性脑缺血作用机理的研究进展

缺血性脑血管疾病是一个非常复杂的病理生理过程 ,是多种机制共同作用的结果。本文从针刺对实验性脑缺血在脑组织形态学改变、血液流变学、脑微循环等方面的研究进展作一综述。     

人胚胎大脑海马发育过程中凋亡神经元超微结构观察

本文借助电子显微镜技术对 4月胎龄组及 6月胎龄组水囊引产胎儿海马中段部位的凋亡神经元超微结构进行观察、拍照 ,并对结果进行了分析讨论。结果显示 :两组对象中均可见凋亡神经元 ,所见的凋亡神经元的超微结构变化基本相同 ,即细胞核内有明显的染色质边集和凝结成块的现象 ,并可见核膜皱缩和扭曲。另外 ,6月组凋亡细胞的结构变化较 4月组更为明显。在 6月组细胞质内和核内均有小体出现 ,其他细胞器无显著变化。从而更进一步说明在胚胎海马发育中存在着神经元不同性质的死亡现象 -即正常死亡和凋亡。而且提出 6月组显现出更为明显的凋亡神经元形态变化     

Leiomyosarcoma of the breast: a pathologic and comparative genomic hybridization study of two cases

Leiomyosarcoma is an extremely rare form of primary breast sarcoma. We present the pathologic and genetic findings of two cases of leiomyosarcoma of the breast. The patients were 44 and 52 years of age and they presented with circumscribed masses of 3.0 and 4.5 cm, (greatest dimension) respectively. Microscopically, the two tumors showed diffuse proliferation of spindle cells with oval and blunt-ended nuclei arranged in short fascicles or bundles. There was moderate cytologic atypia in both cases, and 6 and 12 mitotic figures per 10 high power fields, respectively. No epithelial component was identified. The tumor cells were strongly immunoreactive for markers of smooth-muscle differentiation, including desmin, muscle-specific actin, and smooth-muscle actin. Comparative genomic hybridization analysis showed losses of 10q (two of two cases), 13q (two of two cases), 17p (one of two cases), and gains of 1q (one of two cases) and 17p (one of two cases). The patterns of chromosomal imbalances identified in leiomyosarcoma of the breast are similar to those reported in leiomyosarcoma of soft tissue and uterus and are different from those reported for leiomyoma, indicating that these alterations may be important for development of malignant smooth-muscle tumors regardless of site or organ of origin.     

Haplotype analysis in multiple crosses to identify a QTL gene

Identifying quantitative trait locus (QTL) genes is a challenging task. Herein, we report using a two-step process to identify Apoa2 as the gene underlying Hdlq5, a QTL for plasma high-density lipoprotein cholesterol (HDL) levels on mouse chromosome 1. First, we performed a sequence analysis of the Apoa2 coding region in 46 genetically diverse mouse strains and found five different APOA2 protein variants, which we named APOA2a to APOA2e. Second, we conducted a haplotype analysis of the strains in 21 crosses that have so far detected HDL QTLs; we found that Hdlq5 was detected only in the nine crosses where one parent had the APOA2b protein variant characterized by an Ala61-to-Val61 substitution. We then found that strains with the APOA2b variant had significantly higher (P < or = 0.002) plasma HDL levels than those with either the APOA2a or the APOA2c variant. These findings support Apoa2 as the underlying Hdlq5 gene and suggest the Apoa2 polymorphisms responsible for the Hdlq5 phenotype. Therefore, haplotype analysis in multiple crosses can be used to support a candidate QTL gene.     

Impaired hepatocyte survival and liver regeneration in Atm-deficient mice

Atm is a stress-induced DNA damage checkpoint protein kinase with multiple roles in cell-cycle progression. Recent evidence indicates that Atm also plays a role in stem cell maintenance and self-renewal. It is not known whether Atm has a role during tissue regeneration. Using liver regeneration as a model system, we examined the role of Atm in this process. Here, we show that the expression levels of Atm protein were gradually increased during liver regeneration and this was correlated with the onset of DNA replication. The induction of Stat3 and JNK signaling, which are essential processes in normal regeneration response, was attenuated during the early phases of liver regeneration in Atm-deficient mice. P53 was transiently phosphorylated at serine 23 during liver regeneration in an Atm-dependent manner. In addition, we found that cyclin A induction was delayed and p21 was over-expressed, both of these processes were correlated with reduced and delayed DNA replication in Atm(-/-) mice during liver regeneration. Finally, we show that increased apoptosis was observed in Atm(-/-) mice in response to partial hepatectomy, indicating that Atm is required for the survival of hepatocytes. Collectively, these data indicate that liver regeneration is impaired in Atm-deficient mice. Given that liver is the first line of defense against environmental toxins, the elucidation of the function of Atm and Atm-mediated signaling pathways in liver metabolism and in response to environmental toxins is of fundamental interest.