Environmental and developmental signals modulate proline homeostasis: evidence for a negative transcriptional regulator.

In many plants, osmotic stress induces a rapid accumulation of proline through de novo synthesis from glutamate. This response is thought to play a pivotal role in osmotic stress tolerance [Kishor, P. B. K., Hong, Z., Miao, G.-H., Hu, C.-A. A. and Verma, D. P. S. (1995) Plant Physiol. 108, 1387-1394]. During recovery from osmotic stress, accumulated proline is rapidly oxidized to glutamate and the first step of this process is catalyzed by proline oxidase. We have isolated a full-length cDNA from Arabidopsis thaliana, At-POX, which maps to a single locus on chromosome 3 and that encodes a predicted polypeptide of 499 amino acids showing significant similarity with proline oxidase sequences from Drosophila and Saccharomyces cerevisiae (55.5% and 45.1%, respectively). The predicted location of the encoded polypeptide is the inner mitochondrial membrane. RNA gel blot analysis revealed that At-POX mRNA levels declined rapidly upon osmotic stress and this decline preceded proline accumulation. On the other hand, At-POX mRNA levels rapidly increased during recovery. Free proline, exogenously added to plants, was found to be an effective inducer of At-POX expression; indeed, At-POX was highly expressed in flowers and mature seeds where the proline level is higher relative to other organs of Arabidopsis. Our results indicate that stress- and developmentally derived signals interact to determine proline homeostasis in Arabidopsis.     

尼卡地平控制性降压对家犬脊髓血流的影响

目的　观察尼卡地平控制性降压对家犬脊髓血流的影响。方法　成年杂种犬 6只 ,体重 12 5～ 16kg ,以 2 5 %硫喷妥钠麻醉。股动脉置管监测MAP。以尼卡地平 8μg·kg 1·min 1持续静脉注射控制性降压。以激光多普勒血流仪测定脊髓血流 (SCBF)。结果　降压前MAP为 (12 5 7±10 6 )mmHg ,降压后为 (72 0± 11 2 )mmHg ,平均下降 4 2 8%。降压前SCBF为 (9 80± 1 0 5 )v ,降压后为 (8 0 4± 0 96 )v ,降低幅度为 18%。结论　尼卡地平控制性降压对SCBF影响较小 ,可安全用于脊髓手术。     

以乙二胺为核心的聚酰胺-胺树形高分子的合成及毛细管电泳分离研究

在-30℃下合成了1．0G～6.0G聚酰胺．胺(PAMAM)树形高分子，并采用核磁共振、元素分析对其进行了表征；采用毛细管电泳对1．0GPAMAM进行了分离。结果表明：在该温度下合成的PAMAM具有较好的结构完整性，而毛细管电泳是一种有效的分离提纯PAMAM树形高分子的方法。     

人resistin基因原核表达载体构建和表达

[目的]构建人resistin基因原核表达载体并观察其表达,为开展对resistin的研究打下实验基础.[方法]酚氯仿一步法从一位2型糖尿病合并胆管癌患者腹壁皮下脂肪组织抽取总RNA,RT-PCR法扩增出re-sistin基因cDNA,经测序后,PCR产物亚克隆入T载体,用EcoRI和KpnI分别酶切重组T质粒和原核表达载体pGENKS,然后resistin基因片段和表达载体通过T4DNA连接酶进行定向连接,用核酸内切酶EcoRI、KpnI酶切和测序方法鉴定出重组表达质粒.重组表达质粒转化大肠杆菌JM109,经1 mmol/LIPTG在32℃诱导表达2 h,裂解细菌,进行PAGE凝胶电泳鉴定融合蛋白的表达.[结果]RT-PCR扩增产物分子大小为327 bp,序列分析表明为人resistin基因完整编码区.PCR产物与T载体连接、转化大肠杆菌后,从细菌质粒中酶切回收了目的片段.重组表达质粒经EcoRI和KpnI双酶切后能产生出327 bp、4 980 bp大小的两个片段,序列分析表明重组表达质粒包含人resistin基因完整编码区,基因编码无移位,PAGE凝胶电泳表明在细菌裂解上清有分子质量为39.5 kD的融合蛋白.[结论]成功构建了人resistin基因原核表达载体,且构建的载体能表达出含目的蛋白的融合蛋白,为下一步研究打下了实验基础.     

重症肌无力抗乙酰胆碱受体单链抗体基因的构建

[目的 ]构建重症肌无力抗乙酰胆碱受体主要免疫原区单链抗体A 7基因 .[方法 ]应用PCR技术及基因克隆技术分两步完成重链和轻链可变区基因的克隆 ,再对构建的单链抗体A 7基因进行序列测定检测其核苷酸序列 .[结果 ]构建的重组质粒经序列分析 ,重链可变区基因长度为 36 9bp ,轻链可变区基因长度为 32 1bp ,单链抗体基因长度为 735bp ;单链抗体A 7基因正确地插入在载体质粒pHEN 2开放读码框架内 .[结论 ]成功地构建重症肌无力抗乙酰胆碱受体主要免疫原区单链抗体A 7基因 ,为进一步制备基因工程抗体奠定了基础 .     

麻痹性痴呆12例临床分析

目的探讨麻痹性痴呆(GPI)患者的临床表现,实验室检查、影像学、脑电图特征以及诊断、治疗及预后。方法回顾性分析经临床和实验室确诊的12例GPI患者的相关资料。结果GPI患者临床以智能障碍、精神异常、癫痫最常见。12例患者血清甲苯胺红凝集试验(TRUST)和梅毒螺旋体明胶凝集试验(TPPA)均( ),脑脊液TPPA均( ),而TRUST( )9例。头颅MRI检查结果示大脑皮质萎缩。3例以肢体抽搐为表现者脑电图可见广泛中高幅尖慢波,余脑电图为弥漫性慢波。经抗梅毒治疗,痊愈4例,显效5例,好转3例。结论GPI现已是我国神经梅毒分型中极常见类型,多见于中年男性,临床表现多变,早期误诊率高,早期发现、及时正规治疗预后好。     

急性冠脉综合征中妊娠相关蛋白-A与斑块不稳定性

目的探讨妊娠相关蛋白-A(PAPP-A)在急性冠脉综合征(ACS)中的变化及其与斑块不稳定性的关系。方法26例冠脉正常者作为对照组,稳定性心绞痛(SA)组22例,ACS组40例,包括不稳定性心绞痛(UA)20例、急性心肌梗死(AMI)20例。定量检测外周血PAPP-A、C-反应蛋白(CRP)、肌酸激酶MB同工酶(CK-MB)。对所有冠脉造影显示狭窄≥30%的病变进行影像学分析。结果ACS中PAPP-A含量(13·19±4·04)mIU/L明显高于SA(5·47±3·00)mIU/L(P<0·01)及对照组(5·09±2·19)mIU/L(P<0·01);并且与CRP(r=0·62P<0·01)、复杂性狭窄的数量(r=0·45P<0·05)有显著的正相关。结论PAPP-A在ACS患者外周血中明显升高,可能与斑块的不稳定性有关,对ACS的危险度分层可能具有一定的价值。     

Isolation and differentiation of embryonic stem cells from BALB/c mouse

Objective To invest the efficient method which can culture and induce embryonic stem cells to neurocyte in vitro. Methods Isolate the blastula of 3.5 d from BALB/c species mouse. Culture the cells from inner cell mass (inner cell mass, ICM) which were isolated by mechanical method on the mouse embryonic fibroblaste cell (MEF) feeder layer or 0.1% gelatin coated dishes. The stem cells were identified by characterized morphology, alkaline phosphatase stain, differential potency in vivo and immunochemistry stain. The isolated cells were differentiated by serial induction method that mimicking the intrinsic developmental process of the neural system. Results The isolated cells were positive for alkaline phosphatatse and SSEA-1 (stage specific embryonic antigen 1). Moreover they were identified pluripotent by differentiation in vivo. Therefore the isolated cells presented the characters of ESCs. Then the isolated cells were able to differentiate into neurocytes in vitro. Conclusion Mouse embryonic stem cells isolation, culture and differentiation system has been established.     

幽门螺旋菌菌体蛋白质初步研究

用聚丙烯酰胺凝胶电泳(SDS—PAGE)分析幽门螺旋菌(HP),其超声粉碎和冻融抗原有7条主要蛋白质条带,分子量为71kd、62kd、58kd、51kd、29kd、22kd和12kd。免疫印迹法发现HP100kd免疫性强、特异性高。HP外膜蛋白质分子量主要为71kd、58kd、29kd和12kd,HP不同林之间SDS—PAGE图谱相似,但与空肠弯曲菌和结肠弯曲菌明显不同。超声粉碎和冻融处理HP后主要蛋白质条带相同,冻融抗原制备简单,适宜作为ELISA使用抗原。     

50种传统清热解毒药的抑菌实验

本文报告了传统药物文献收载的５０种清热解毒药的抑菌实验结果。显示抑菌作用的有４１种，占８２％。对阳性球菌显示有抑菌作用的有３６种；对阴性杆菌显示有抑菌作用的有２４种。其中的地胡椒、金果榄、毛果算盘子等显示有较广的抗菌效应，值得进一步研究。