生物学标志在产肠毒素性大肠埃希菌同源克隆鉴定中的应用

目的研究多方法、多生物学标志在产肠毒素性大肠埃希菌同源克隆鉴定中的作用。方法在毒力基因检测和分型基础上，首次采用质粒分析法结合多位点酶电泳法，对ＥＴＥＣ同源克隆进行了综合研究。结果７个毒力基因型的２０６株散发ＥＴＥＣ菌株经质粒图谱分型后，共可分成９３个质粒型，有１４０株ＥＴＥＣ具有独特的基因型；进一步用多位点酶电泳分型，２０６株ＥＴＥＣ可被分成１４８个ＥＴ型，３种方法综合，共有１９０株ＥＴＥＣ具有独特的基因型。结论多方法、多生物学标志在同源克隆鉴定中能提供更多、更可靠的信息。     

A new HPLC fluorimetric method to monitor urinary delta-aminolevulinic acid (ALA-U) levels in workers exposed to lead

Summary A new sensitive HPLC method for the determination of urinary delta-aminolevulinic acid (ALA-U) was used to evaluate the relationship between blood-lead (Pb-B) and ALA-U levels in male workers exposed to lead. The differences between the ALA-U levels determined by this method (ALAU-HP) and by a colorimetric method (ALA-U-CL) are discussed. The HPLC method gave values similar to the ALA-U-CL values at high ALA-U level. However, at low blood-lead levels (58 ± 22 g/l, n = 23), the mean ALA-U-HP level corrected by urinary creatinine level was one-third of the corrected ALA-UCL level (0.83 ± 0.14 and 2.4 ± 0.5 mg/g creatinine, respectively). A significant increase of the mean corrected ALA-U-HP level was observed at 162 ± 22 g/l Pb-B (P < 0.05, n = 26), while that of ALA-UCL was observed at 245 ± 30 g/l Pb-B (P < 0.01, n = 37). The regression equation based on the logistic model fitted well to the relationship data between the Pb-B level and the percentage of the subjects with corrected ALA-U-HP above the cut-off point (1.12 mg/g creatinine) and the expected Pb-B level for 50% response was 270 g/l Pb-B, while it did not fit well to the relationship data between Pb-B level and the percentage of the subjects with corrected ALAU-CL above the cut-off point (3.5 mg/g creatinine). The maximum responses for the two sets of corrected ALA-U levels were both observed at 625 ± 25 g/l. The corrected ALA-U level by HPLC method seems to be a useful indicator for biological monitoring of exposure to lead at low levels (< 400 g/l Pb-B = health-based biological limit, WHO) as well as high ones.     

Historical evolution,overview, and therapeutic manipulation of co-stimulatory molecules

Co-stimulatory molecules are key mediators in the regulation of immune responses and knowledge of its different families, structure, and functions has improved in recent decades. Understanding the role of co-stimulatory molecules in pathological processes has allowed the development of strategies to modulate cellular functions. Currently, modulation of co-stimulatory and co-inhibitory molecules has been applied in clinical applications as therapeutic targets in diseases and promising results have been achieved.     

Meta-analysis of gross insertions causing human genetic disease: novel mutational mechanisms and the role of replication slippage

Although gross insertions (>20 bp) comprise <1% of disease-causing mutations, they nevertheless represent an important category of pathological lesion. In an attempt to study these insertions in a systematic way, 158 gross insertions ranging in size between 21 bp and approximately 10 kb were identified using the Human Gene Mutation Database (www.hgmd.org). A careful meta-analytical study revealed extensive diversity in terms of the nature of the inserted DNA sequence and has provided new insights into the underlying mutational mechanisms. Some 70% of gross insertions were found to represent sequence duplications of different types (tandem, partial tandem, or complex). Although most of the tandem duplications were explicable by simple replication slippage, the three complex duplications appear to result from multiple slippage events. Some 11% of gross insertions were attributable to nonpolyglutamine repeat expansions (including octapeptide repeat expansions in the prion protein gene [PRNP] and polyalanine tract expansions) and evidence is presented to support the contention that these mutations are also caused by replication slippage rather than by unequal crossing over. Some 17% of gross insertions, all >or=276 bp in length, were found to be due to LINE-1 (L1) retrotransposition involving different types of element (L1 trans-driven Alu, L1 direct, and L1 trans-driven SVA). A second example of pathological mitochondrial-nuclear sequence transfer was identified in the USH1C gene but appears to arise via a novel mechanism, trans-replication slippage. Finally, evidence for another novel mechanism of human genetic disease, involving the possible capture of DNA oligonucleotides, is presented in the context of a 26-bp insertion into the ERCC6 gene.     

S-99和S-100止血作用研究

PT、APTT、TT、血小板粘附率和血栓形成试验表明S-99可溶性止血纺织材料和S·100吸收性止血綾的止血效果无显著差异。但是S-99和S-100止血纺织材料的止血机理不尽相同,S-100止血绫主要是通过溶解后的负电性液相激活内源性止血系统;而S-99止血纺织材料主要是通过溶胀胶粒粘附血小板,进而激活血小板。     

In vivo electrical characteristics of human skin, including at biological active points

The aim is to compare the mean values of the in vivo electrical characteristics of bioiogical active points (BAPs) with those of the surrounding human skin. The impedance measurements at BAPs and on the surrounding skin are carried out in vivo on ten young, healthy people. The results of the measurements show that the BAP resistance R_P is smaller, and the capacitance C_P is higher, than the corresponding values for skin, R_S and C_S, respectively, these differences are larger at low frequencies (at f=3 Hz, R_S/R_P=3.19 and C_P/C_S=3.2). The mean values of the impedance measurements at the BAPs are different from those measured on the skin. The dependence of R_P and C_P on the pressing force, in the range of about 1–5 N, for the BAPs, has a smaller slope than that observed for the surrounding skin. An equivalent circuit for the BAPs is proposed that describes sufficiently well the experimental results obtained. These results show that the large dispersion in the observed impedance characteristics of the human body measurements in different body regions can be related to the influence of the BAPs present under the electrodes.     

尼古丁依赖的功能影像学研究进展

在过去10年中,随着功能脑影像学技术在物质滥用领域的发展,越来越多的研究者运用这些技术以探讨尼古丁成瘾的神经生物学机制。本文主要总结了尼古丁急、慢性暴露下对脑功能影响的神经脑影像学研究进展,证实了尼古丁依赖与中脑边缘犒赏系统、调节注意、记忆、运动以及联想相关脑环路之间的相关性。这些研究发现将为揭示尼古丁依赖的神经生物学机制提供更多的证据支持,进一步促进今后戒烟治疗的发展。     

物质成瘾Stroop效应研究进展

物质成瘾Stroop任务是考察物质成瘾者对成瘾相关刺激产生注意偏向的一种研究范式。研究者们采用多种实验任务和研究方法,对物质成瘾Stroop干扰产生的心理机制进行了考察,并提出了几种理论解释,但目前这些理论解释之间还存在一定的分歧。最后,本文提出了未来研究的一些建议。     

Double minutes and other chromosomal aberrations in two malignant cell lines of the German cockroach Blattella germanica

Structural anomalies of mitotic chromosomes from two tumorigenic cell lines of the German cockroach (Blattella germanica) is described. Aberrations, such as unpairable marker chromosomes, double minutes, di- and tricentrics, ring chromosomes, tri- and quadriradials, and chromosome and chromatid gaps and breaks, were observed in varying proportions. This study reports that the double minute chromosomes (DMs) are associated with insect tumor cells, similar to the findings in both murine and human tumor cells.     

原发性肝癌患者抑郁症状与不成熟防御机制的关系

目的：了解原发性肝癌（PLC）患者的抑郁症状和不成熟防御机制（IDM）的水平，探讨PLC患者的抑郁症状与IDM的关系。方法：采用流调用抑郁自评量表（CES－D）和防御式方式问卷（DSQ）对PLC患者和健康组各100例进行调查。结果：1）PLC患者中49％可能或肯定有抑郁症状，其中23％肯定有抑郁症状，其发生率高于健康组；2）PLC组的CES－D总分高于健康组；3）PLC组比健康组采用较多分裂和潜意显现机制，采用较少抱怨机制；4）肯定有抑郁症状者比无抑郁症状者采用较多IDM；5）两组CES－D总分与IDM均分呈显著正相关，Pearson r为0.473-0.776，其中PLC组为0．473。结论：抑郁症状是PLC患者常见的负性情绪，医护人员应引起重视，并指导患者采用成熟的防御机制代替不成熟防御机制，预防并减轻患者的抑郁症状，以提高患者的生活质量。