Parvalbumin 3 is an Abundant Ca2+ Buffer in Hair Cells

Ca2+ signaling serves distinct purposes in different parts of a hair cell. The Ca2+ concentration in stereocilia regulates adaptation and, through rapid transduction-channel reclosure, underlies amplification of mechanical signals. In presynaptic active zones, Ca2+ mediates the exocytotic release of afferent neurotransmitter. At efferent synapses, Ca2+ activates the K+ channels that dominate the inhibitory postsynaptic potential. A copious supply of diffusible protein buffer isolates the three signals by restricting the spread of free Ca2+ and limiting the duration of its action. Using cDNA subtraction and a gene expression assay based on in situ hybridization, we detected abundant expression of mRNAs encoding the Ca2+ buffer parvalbumin 3 in bullfrog saccular and chicken cochlear hair cells. We cloned cDNAs encoding this protein from the corresponding inner-ear libraries and raised antisera against recombinant bullfrog parvalbumin 3. Immunohistochemical labeling indicated that parvalbumin 3 is a prominent Ca2+-binding protein in the compact, cylindrical hair cells of the bullfrog's sacculus, and occurs as well in the narrow, peanut-shaped hair cells of that organ. Using quantitative Western blot analysis, we ascertained that the concentration of parvalbumin 3 in saccular hair cells is approximately 3 mM. Parvalbumin 3 is therefore a significant mobile Ca2+ buffer, and perhaps the dominant buffer, in many types of hair cell. Moreover, parvalbumin 3 provides an early marker for developing hair cells in the frog, chicken, and zebrafish.     

小包装全氟丙烷气体动力学实验研究

为检验塑料小包装全氟丙烷气体（C3F8）在不同包装和储存方法时浓度变化，将装有5～7mlC3F8的聚氯乙烯小袋，根据不同储藏温度和外包装方法随机分成四组：（1）22℃聚乙烯外包装，（2）36℃聚乙烯外包装，（3）22℃铝箔真空外包装，（4）-29℃聚乙烯外包装；每一组C3F8小袋气体存放一定时间后，应用气相色谱分析方法进行浓度测量。结果：第3组C3F8浓度最高和稳定，第2组浓度随放置时间降低最明显，第4组是临床应用气体的储藏和包装方法，其30天样本浓度和第3组相等，但放置一年时浓度降低。结果显示：塑料小包装C3F8予以铝箔真空外包装是一种可行的方法，利于C3F8运输和普及；聚乙烯外包装的C3F8，应放在-29℃保存，时间不超过一年。     

芬太尼／哌替啶致Oddi括约肌痉挛的探讨

２００例择期胆囊切除＋术中胆道造影患者分二组；芬太尼１７ｕｇ／ｋｇ静注（Ｆ组，ｎ＝１００）、哌替啶１ｍｇ／ｋｇ静注。评价两种麻醉性镇痛药致Ｏｄｄｉ括约肌痉挛的发生率，结果：８例病人造影剂不能通过Ｏｄｄｉ括约肌、十二指肠不显影，胆总管下端显示“鸟嘴样”或“假结石”影像，后者３例病人胆总管探查阴性，静注纳络酮０．４ｍｇ后，全部病例造影剂顺利进入十二指肠。结论：硬膜外麻醉辅用小剂量芬太尼／哌替啶时Ｏｄｄ     

前臂逆行骨间背侧皮瓣的临床应用

目的总结前臂逆行骨间背侧皮瓣的临床疗效。方法回顾性分析42例前臂逆行骨间背侧皮瓣，并结合文献阐明其变异程度及变异的处理。结果骨间背侧血管在前臂中1／3缺如1例．皮瓣边缘坏死；皮瓣向近端延伸超过4cm者4例，远端坏死，延迟愈合；其余均一期愈合：结论虽然前臂骨间背侧血管有变异，但前臂逆行骨间背侧皮瓣仍是修复手背中等大小创面较为理想的方法，以近点皮肤穿支向近端延伸皮瓣不要超过4cm。     

Comparison of fMRI statistical software packages and strategies for analysis of images containing random and stimulus-correlated motion.

The objectives of this study were to use computer-generated phantoms containing real subject motion to: (1) compare the sensitivity of four commonly used fMRI software packages and (2) compare the sensitivity of three statistical analysis strategies with respect to motion correction. The results suggest that all four packages perform similarly in fMRI statistical analysis with SPM2 having slightly higher sensitivity. The most sensitive analysis technique was to perform motion correction and include the realignment parameters as regressors in the general linear model. This approach applies to all four packages examined and can be most beneficial when stimulus-correlated motion is present.     

精神分裂症服用氯氮平能降低其甲状腺素水平的对照分析

目的探索氯氮平治疗是否影响T3、T4和TSH水平.方法对17例精神分裂症患者,给予氯氮平治疗第4天和第4周末分别测定T3、T4和TSH水平.结果治疗第4周末的T3(3.309±0.689)、T4(9.449±1.941)水平比第4天的T3(3.915±0.850)、T4(11.178±2.180)水平明显降低(P均＜0.05).结论氯氮平治疗能降低甲状腺素水平.     

Alpha-tocopherol and beta-carotene do not protect marmosets against the dopaminergic neurotoxicity of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Idiopathic Parkinson's disease (PD) may possibly be caused by one or more unidentified neurotoxins present in the environment, or formed endogenously, which progressively damage dopaminergic nigrostriatal neurons. N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is an experimental neurotoxin which produces biochemical and neuropathological changes in humans, lower primates and mice that closely resemble those found in PD. Because the mechanisms of neuronal damage in both idiopathic PD and in the MPTP model of PD may involve free radical formation in the substantia nigra, antioxidants might protect dopaminergic neurons. Previously, we found that both alpha-tocopherol and beta-carotene partially protected mice against MPTP. However, in the experiments described in this paper, neither alpha-tocopherol nor beta-carotene, each administered in massive doses, had any demonstrable protective effect for dopaminergic nigrostriatal neurons in marmosets injected with low doses of MPTP. Without more knowledge about the identity of the neurotoxin(s) causing idiopathic PD, and their mechanism of action, it is not possible at this time to predict whether these 2 antioxidants might be clinically useful in preventing or ameliorating PD.     

中等职业学校教育教学管理新谈

随着教育制度的改革,中职院校的学生面貌发生了巨大变化。面对新形势,我们应科学借鉴先进的教育理念,合理设置教育目标,为职业教育改革注入新的理念和活力。     

老中青年急性心肌梗塞的临床特点及相关因素分析

急性心肌梗塞(acute myocardial infarction．AMI)是老年人常见的心血管疾病之一。但近年来，中青年AMI发病率有上升趋势，为了解各年龄段AMI的临床特点及其相关因素，现对某院近年来收住的AMI患者进行回顾性对比分析，现报告如下。