Effect of hemorrhage on plasma atriopeptin levels in conscious dogs

An increase in atrial pressure has been shown to cause an increase in the concentration of atrial peptides (atriopeptin) in plasma. We therefore hypothesized that a reduction in atrial pressure would decrease the concentration of atriopeptin in plasma. In formulating this hypothesis we assumed that changes in the concentration of other circulating hormones or changes in cardiac nerve activity during hemorrhage would not affect the secretion of atriopeptin. To test the hypothesis, we bled sham-operated conscious dogs at a rate of 0.8 ml.kg-1.min-1 to decrease right and left atrial pressures. Hemorrhage was continued until a total of 30 ml of blood per kilogram body weight had been removed. Identical experiments were performed on conscious cardiac-denervated dogs. The concentration of plasma atriopeptin was decreased in each group of dogs after 10 ml of blood per kilogram of body weight had been removed, but the decrease achieved statistical significance only in the cardiac-denervated dogs. Further hemorrhage, however, produced no further decreases in circulating atriopeptin in either group even though atrial pressures continued to decline as more blood was removed. A comparison of the atriopeptin response to hemorrhage revealed no significant difference between the sham-operated and cardiac-denervated dogs, thus providing no evidence for a specific effect of cardiac nerves on atriopeptin secretion during hemorrhage. Our results demonstrate that the relationship between atrial pressure and plasma atriopeptin that has been observed repeatedly during atrial stretch is not evident during relatively slow, prolonged hemorrhage. There is, however, a small decline in circulating atriopeptin during the initial stage of hemorrhage that could be of biological significance.     

Localization of the gene encoding human Factor V to chromosome 1q21–25

The gene encoding human coagulation Factor V (FV), one of the cofactors in the blood clotting process, has been mapped to chromosome 1 by both Southern hybridization to DNA from human-hamster somatic cell hybrids and in situ hybridization. The whole plasmid pUC3A containing a 1.5-kb cDNA sequence for FV was 32P-labeled for Southern analysis and 3H-labeled for in situ hybridization to metaphase chromosomes. The results localized the FV gene to the region of 1q21-25.     

A cell type-specific enhancer drives expression of the chick muscle acetylcholine receptor alpha-subunit gene

The regulation of acetylcholine receptor alpha-subunit gene expression was analyzed by transient expression assays. Using rabbit beta-globin cDNA as a reporter gene, we have confirmed that the 5'-flanking sequence of the chicken acetylcholine receptor alpha-subunit gene directs specific expression in differentiated C2C12 cells, a mouse muscle cell line, but not in undifferentiated C2C12 cells and mouse 3T3 fibroblasts. Testing chimeric plasmids containing Bal31 deletion mutants of the alpha-subunit gene upstream sequence, we found the -116 to -81 region of the alpha-subunit to be responsible for tissue- and stage-specific expression. This 36 bp fragment stimulates the activity of both alpha-subunit and SV40 promoters in a distance- and orientation-independent manner, thus fulfilling the criteria of an enhancer.     

我国浙江与日本和我国台湾森林植物区系的联系

作者在“试论浙江省森林植物区系”一文中对我国浙江与日本和我国台湾森林植物区系的联系已作了扼要的说明,本文就是在此基础上作更详尽的论述。浙江省东濒大海,隔海相望,东北方向有日本,其本部岛屿的南端为九州,和浙江北部的纬度相近,具有亚热带气候特征,出现了和浙江相类似的常绿阔叶林和竹林,九     

九江地区人头发横断面的研究

本文对九江市汉族463例健康人,4710根头发横断面进行观察和显微测量。分析了本地区人年龄与头发直径的关系、年龄与头发黑色素颗粒分布的关系。结果表明:黑色素颗粒随年龄增长而渐浓密,成年人最丰富,老年人头发黑色素颗粒则渐崩溃稀少;头发各径亦随年龄增长而增大,而老年人头发各径是逐渐减小。此外,本文还同欧、亚、美国各民族人头发资料进行比较。根据头发指数,确定本市人头发形伏为直发形。     

用体外免疫法建立人—人抗流行性乙型脑炎病毒杂交瘤细胞株

利用单克隆抗体(McAb)进行病毒病的治疗是人们所关心的一个重大课题。 流行性乙型脑炎(乙脑)是一种严重威胁人民健康的急性传染病,病死率高,后遗症严重。国内外目前尚无特效疗法。陈伯权等用乙脑病毒皮下或腹腔感染3周龄小白鼠24、48小时及5天后,分别用乙脑病毒51-8McAb进行治疗,平均治愈率分别为78％、73％及22％。     

小鼠Lewis肺癌组织中层粘连蛋白受体的分离及其性质的研究

层粘连蛋白(Laminin,LN)是基膜(basement membrane)中的一种主要大分子糖蛋白。一些研究资料表明肿瘤细胞的浸润转移可能与LN有关。肿瘤细胞与LN的作用可能是通过细胞表面LN受体进行的。本文采用亲和层析法从小鼠Lewis肺癌组织中分离LN受体并对其理化性质进行研究。Lewis肺癌LN受体的表观分子量为70,000,还原后SDS电泳图为一条较宽的条带。氨基酸组成中疏水氨基酸占38％,苏氨酸、絲氨酸、门冬氨酸(包括门冬酰胺)占23.5％,通过硝酸纤维素膜片法用HRP-LN测定受体与LN的结合特性,证明具有配基结合专一性,饱和性及高亲和性(Kd=0.95×10~(-9)mol/L)。