电化学人工龋的电化学腐蚀机制研究

目的 研究电化学人工龋的电化学腐蚀机制。方法 采用循环伏安法研究牙片电极在K2SO4溶液中的氧化还原反应；以失重法并结合SPSS统计软件统计分析，评价牙片在KCl和K2SO4介质中恒电位腐蚀情况，并现场监测电解液氢离子浓度的变化情况。结果 在0.0-2.5V电位范围内，牙片电极与石墨电极具有波形类似的循环伏安曲线；在KCl和K2SO4介质中牙片的腐蚀速度无显著差异；2.0V恒电位腐蚀牙片8h后，阳极池本体溶液pH值由7.0平均下降到3.87，阴极池则由7.0平均升高到10.65。结论 在外电场作用下，牙片的阳极腐蚀与介质无关；水的阳极氧化引起阳极区氢离子浓度升高，致使牙齿发生酸溶是电化学人工龋形成的主要决定因素。     

Ebstein畸形矫治术的麻醉管理

本院2004年3月至2005年12月手术治疗Ebstein畸形患者22例,男女各11例,年龄3个月-52岁,体重5-80kg。16岁以下患者诱导前肌肉注射氯胺酮6-7mg·kg-1、东莨菪碱0．01 mg·kg-1,意识消失后静脉注射舒芬太尼1μg·kg-1、泮库溴铵0．1-0．2 mg·kg-1麻醉诱导;16岁以上患者麻醉前30min肌肉注射吗啡10mg、东莨菪碱0．3mg,口服安定10mg,静脉注射咪达唑仑0．03-0.05 mg·kg-1、依托咪酯0．2-0.3 mg·kg-1、舒芬太尼1-2μg·kg-1、哌库溴铵0.08-1．0 mg·kg-1麻醉诱导。气管插管后行机械通气,维持呼气末二氧化碳分压(PETCO2)30-35mm Hg。吸入1.0％-1．5％异氟醚,间断静脉注射舒芬太尼和哌库溴铵维持麻醉。连续监测心电图、有创血压、脉搏血氧饱和度、PETCO2、中心静脉压、体温和经食管超声心动图。术中麻醉管理要点为减轻右心室前、后负荷,避免肺血管阻力增加,保护心功能,维持血液动力学稳定。所有患者术后症状明显缓解,右心房内径、右心室内径低于术前,围术期无1例患者死亡。     

硬膜外腔注射生理盐水对剖宫产术患者腰麻效果的影响

目的探讨硬膜外腔注射生理盐水对剖宫产术患者腰麻效果的影响。方法择期行子宫下段剖宫产术患者60例,年龄24～30岁,体重59～73 kg,随机分为2组,每组30例,A组蛛网膜下腔注射规定剂量的0.75%布比卡因后硬膜外腔注射生理盐水5 ml;B组蛛网膜下腔注射0.75%布比卡因。按序贯法进行试验,设定布比卡因的起始剂量为9 mg,剂量梯度为1.5 mg,若上一例有效,则下一例递减一个剂量梯度,若无效则下一例递增一个剂量梯度,蛛网膜下腔阻滞有效的标准为注射布比卡因后20 min内阻滞上平面达T5。采用概率单位法计算ED50。结果A组布比卡因的ED50（5.8 mg）低于B组（8.1 mg）,两组比值为0.72,95%置信区间为0.27～0.98,区间范围不包括1,差异有统计学意义（P〈0.05）。结论硬膜外腔注射生理盐水可增强剖宫产术患者腰麻的效果。     

Comparative inotropic effect of calcium, endothelin-1, and forskolin on ferret papillary muscles during acidosis

Summary— Acidosis affects multiple steps in the excitation-contraction coupling pathway of myocardium, producing decreased calcium sensitivity of myofibrils and modification of the function of the sarcoplasmic reticulum. Our aim was to evaluate the effectiveness of three different classes of inotropic agents under acidotic conditions: 1) forskolin, an adenylate cyclase activator that enhances cellular cyclic AMP concentrations, 2) elevated extracellular Ca²⁺ and 3) endothelin-1, an activator of the inositol triphosphate, diacylglycerol pathway. Ferret papillary muscles were mounted in organ baths containing normal physiological solution (pH = 7.4). After baseline tension was measured, the muscles were bathed in an acidotic solution (pH = 6.98) that decreased tension to 40% of the control; subsequently, the muscles were washed with normal physiological solution until they returned to baseline. Each inotropic agent was added to the bathing solution in a concentration sufficient to increase tension by 40% above the baseline. Then the solution was made acidotic (pH = 6.98) in the continuous presence of that concentration of inotropic agent and the resultant steady-state developed tension measured. The increases in tension induced by each inotropic agent at normal pH were adjusted to be similar; in contrast, the response to each drug in acidosis was significantly different. Under acidotic conditions, endothelin-1 was the most effective inotropic agent in restoring the depressed developed tension. This was possibly due to enhancement of the myofilament sensitivity to Ca²⁺, which was more effective than increasing [Ca²⁺]_i through elevating extracellular Ca²⁺ or the addition of forskolin which increased [Ca²⁺]_i but desensitized the myofilaments to Ca²⁺.     

我国医疗保障制度改革中医院配套改革措施探讨

论述了医疗保障制度改革给医院带来的机遇与挑战,认为医院应采取调整结构,转换运行机制;完善补偿机制;加大宏观调控力度,制订和实施区域卫生规划等配套措施,来适应医疗保障制度的改革。     

Effect of single-dose omeprazole and ranitidine on gastric juice acidity and volume in patients undergoing laparotomy

The effects of oral omeprazole and oral ranitidine on gastric fluid volume and pH were compared in 95 elective surgical patients, randomly assigned to one of three groups. The patients received either 80 mg of omeprazole or 300 mg of ranitidine orally at 6.00 on the morning of surgery. One third of the patients received no antacid therapy. Following induction, a no. 18 nasogastric tube was passed into the stomach and all available gastric fluid was aspirated. pH and volumes were measured. In the omeprazole- and ranitidine-treated groups, the mean pH was > 5.4 after induction, at completion of surgery and 1 h after operation, although at least one patient in both groups had pH < 2.5. The volumes of gastric aspirates were reduced equally by both drugs. Two patients in the omeprazole group, none in the ranitidine group and eight in the control group (26%) had pH <2.5 with volume> 25 ml at induction. Both drugs appeared to be effective in reducing the volume of intragastric fluid and acidity to acceptable values.     

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.     

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。     

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。