耳蜗外毛细胞Prestin的研究进展

哺乳动物耳蜗外毛细胞能响应膜电位变化，其长度和劲度(stiffness)均能发生迅速改变．外毛细胞的这种电动性被认为是由分子马达(motor)驱动，能产生耳蜗机械放大，Prestin特异地在外毛细胞内表达．近年的研究认为Prestin正是耳蜗外毛细胞的分子马达．对近年来有关Prestin的结构功能特性的研究结果进行了较详细论述．     

斯氏鼢鼠耳蜗形态对感知低频声波的适应

利用光学显微镜和透射电子显微镜技术对斯氏鼢鼠(Myospalax smithi)耳蜗进行显微和超显微水平观察，分析了其对低频声波感知的结构基础．结果表明，斯氏鼢鼠的耳蜗与其它哺乳类存在区别，蜗顶处螺旋神经节的数目多于蜗底；盲鼹鼠(Spalax ehrenbergi)耳蜗所不具有的传出神经纤维在斯氏鼢鼠耳蜗的电镜切片上可见，这有利于斯氏鼢鼠对不同频率声波的更精确的感知；最顶部的半圈蜗管上有两排内毛细胞，而没有外毛细胞．在长期的进化适应过程中，斯氏鼢鼠耳蜗产生了独特的结构以完成和洞道中其它个体的通讯。     

新工艺 新产品 新设备

梨果灵浙江大学园艺系与杭州果树研究所及大观山果园合作．经过６年的试验与研究，开发研制成功能促使梨树优质高产的生长调节剂“梨果灵”，并于今年１月通过浙江大学组织的专家鉴定，经与会专家评审，一致认为该项研究成果处于国内领先水平。以这种“梨果灵”于梨树开花后２０～４５天涂擦小梨果柄，能显著促进和延长梨果细胞分裂，增加果实细胞数目和增大细胞组织，加速果实的发育和成熟。从而促使梨果增大果形、改善品质与提早成熟．使梨果可以提早７～１０天上市，增加经济效益．以及减小某些品种的裂果比率和具有一定的防治黑斑病作用…     

沼液在育肥猪养殖上增重效果的对比试验

选择本地杂交猪16头，分成三个组在三个沼气户家饲喂，第一组4头，其中试验2头、对照2头，第二组6头，其中试验3头、对照3头，第三组6头，其中试验3头、对照3头。经1个月的对比试验，试验组比对照组的猪平均日增重多0．175公斤，皮毛比对照组的提前3天发红．可以提早10—15天出栏。     

注射铁制剂对绵羊促生长效果的试验研究

本试验对新生羔羊、2月龄羔羊、育成羔羊、育肥羊分别注射牲血索，结果表明：注射牲血素50天试验组比对照组新生羔羊可提高增重24．11％；2月龄羔羊50天增重提高15．17％；对育成母牛和育肥羊无影响。经济效益上新生羔羊和2月龄羔羊投入与增加纯收比达1：30和1：18以上。注射牲血素可提高新生羔羊和2月龄羔羊的成活率，分别高6个和35个百分点；发病率减少了7个和4个百分点。     

天然植物中草药添加剂对奶牛生产性能的影响

试验采用不同中草药配成Ⅰ、Ⅱ、Ⅲ三种中：草药添加剂．供试奶牛52头随机分为对照组和试验A、B、C四个组．对照组不饲喂中草药，试验A、B、C组分别饲喂Ⅰ、Ⅱ、Ⅲ中草药添加剂．实验组每天每头平均饲喂50g中草药添加剂．45天的实验结果表明，每天每头平均产奶量，试验A组与对照组相比增加1．57％（P〉0.05），试验B、C组比对照组分别提高4．5196（P〈0．05）,3.96％（P〈0．05），实验Ⅱ组比对照组每头每天平均增加效益0．95元．但各组间采食量无明显影响，实验组对隐性乳房炎有明显的预防作用．     

PP333对花生营养器官的形态和叶片超微结构的影响

本文报道了多效唑（ＰＰ３３３）喷施花生对植株性状、茎叶形态及结构的影响．结果表明：ＰＰ３３３能抑制花生主茎生长，节间缩短变粗，一级分枝数目增多，茎维管束长度变短，宽度增加，叶片变短，厚度增加，叶肉栅栏组织也增厚，叶片表面细胞变小，密度增大，气孔变小，叶绿体基粒片层数目减少，抑制叶绿体发育．     

电刺激小脑顶核促脑缺血后血管内皮生长因子表达的意义

探讨电刺激小脑顶核(FNS)对局部脑缺血后血管内皮生长因子(VEGF)表达和毛细血管新生的影响．以线栓法制成大鼠右侧大脑中动脉梗塞模型(MCAO)，大鼠随机分为假手术对照组、MCAO组、电刺激小脑顶(MCAO FNS)干预组，以免疫组织化学法检测VEGF、内皮细胞阳性表达及毛细血管记数，大脑中动脉梗塞后，缺血区神经元变性、坏死，VEGF、内皮细胞在半暗带有少量表达，毛细血管数较对照组增加，经电刺激小脑顶核干预后，VEGF、内皮细胞大量表达，毛细血管数目明显增加，有统计学差异．电刺激小脑顶核可通过促VEGF表达、内皮细胞增殖，从而促进毛细血管新生。     

溢多酶V_(10R)─818饲喂断奶仔猪效果试验

本试验将32头断奶仔猪随机分为2组，试验组日粮中添加0．1％的溢多酶V（10R）──818，对照组不添加溢多酶V（10R）──818，饲喂30天。结果，试验组日增重586克，对照组日增重547克，经t检验，差异显著（P＜0．5）；试验组料肉比1．74：1，比对照组降低6．95％；而且试验组仔猪腹泻发病率比对照组降低18．75％。试验组每头仔猪比对照组多获利17．12元（仔猪单价按每千克15元）。     

不同分子量的探针在细胞间的运输

利用Ｏｐｔｏｎ显微注射系统（Ｍｉｃｒｏｉｎｊｅｃｔｉｏｎｓｙｓｔｅｍ）将不同分子量的荧光分子探针分别注射到不同生育期的紫竹梅雄蕊花丝毛细胞内，在ＯｌｙｍｐｕｓＢＨ—２型荧光显微镜下观察探针在细胞内的转移情况，取得以下结果，花蕾和开放花的雄蕊花丝毛细胞的胞间连丝允许ＬＲＢ（５５９Ｄａ），ＦＩＴＣ－（Ａｌａ）６（８７０．３Ｄａ）通过，而ＦＩＴＣ－Ｌｅｕ－Ａｒｇ－Ａｒｇ－Ａｌａ－Ｓｅｒ－Ｖａｌ－Ａｌａ（１１６１．３Ｄａ）难以通过．花蕾和开放花的雄蕊花丝毛细胞间的胞间连丝的通透性差异不大．且允许通过的分子探针不超过１１６１．３Ｄａ．在花蕾和开放花的雄蕊花丝毛细胞间不能通过的分子探针ＦＩＴＣ－Ｌｅｕ－Ａｒｇ－Ａｒｇ－Ａｌａ－Ｓｅｒ－Ｖａｌ－Ａｌａ（１１６１．３Ｄａ），ＦＩＴＣ－ＩｎｓｕｌｉｎＡＣｈａｉｎ（２９２１．０Ｄａ）在衰老花雄蕊花丝毛细胞间可以转移，但分子量为４４００．０Ｄｅ和９４００．０Ｄａ的ＦＩＴＣ－Ｄｅｒｔｒａｎ探针却难以转移．胞间连丝的通透性能，随着植物的生长发育发生相应的变化．     

不同年龄虎皮鹦鹉发声行为的研究

本文通过采用生物信号采集处理系统对不同发育阶段的虎皮鹦鹉的声音进行了分析.结果发现:(1)随着虎皮鹦鹉的成长,叫声越来越复杂,幅度越来越高;(2)在成长的过程中,雄鸟比雌鸟的叫声更复杂,但幅度不如雌鸟的高.     

Hair cell synaptic ribbons are essential for synchronous auditory signalling

Hearing relies on faithful synaptic transmission at the ribbon synapse of cochlear inner hair cells (IHCs). At present, the function of presynaptic ribbons at these synapses is still largely unknown. Here we show that anchoring of IHC ribbons is impaired in mouse mutants for the presynaptic scaffolding protein Bassoon. The lack of active-zone-anchored synaptic ribbons reduced the presynaptic readily releasable vesicle pool, and impaired synchronous auditory signalling as revealed by recordings of exocytic IHC capacitance changes and sound-evoked activation of spiral ganglion neurons. Both exocytosis of the hair cell releasable vesicle pool and the number of synchronously activated spiral ganglion neurons co-varied with the number of anchored ribbons during development. Interestingly, ribbon-deficient IHCs were still capable of sustained exocytosis with normal Ca2+-dependence. Endocytic membrane retrieval was intact, but an accumulation of tubular and cisternal membrane profiles was observed in ribbon-deficient IHCs. We conclude that ribbon-dependent synchronous release of multiple vesicles at the hair cell afferent synapse is essential for normal hearing.     

Prestin is the motor protein of cochlear outer hair cells

The outer and inner hair cells of the mammalian cochlea perform different functions. In response to changes in membrane potential, the cylindrical outer hair cell rapidly alters its length and stiffness. These mechanical changes, driven by putative molecular motors, are assumed to produce amplification of vibrations in the cochlea that are transduced by inner hair cells. Here we have identified an abundant complementary DNA from a gene, designated Prestin, which is specifically expressed in outer hair cells. Regions of the encoded protein show moderate sequence similarity to pendrin and related sulphate/anion transport proteins. Voltage-induced shape changes can be elicited in cultured human kidney cells that express prestin. The mechanical response of outer hair cells to voltage change is accompanied by a 'gating current', which is manifested as nonlinear capacitance. We also demonstrate this nonlinear capacitance in transfected kidney cells. We conclude that prestin is the motor protein of the cochlear outer hair cell.     

内耳免疫反应诱导Bcl-2和Bax表达研究

探讨内耳免疫反应过程是否引起细胞凋亡以及Bcl-2和Bax的表达情况。选用雌性白色豚鼠16只，随机分为实验组和对照组各8只，以钥孔虫戚血蓝蛋白（KLH）全身免疫后，实验组以相同抗原进行内耳免疫，对照组内耳注射等量的磷酸盐缓冲生理盐水（PBS），在内耳免疫5d后处死动物，取内耳免疫侧耳蜗制作石蜡切片。通过免疫组化检测内耳Bcl-2和Bax的表达。结果表明，内耳免疫反应可以诱导细胞凋亡的发生以及Bcl-2和Bax蛋白在其中起了重要的调节作用。     

Sound-induced motility of isolated cochlear outer hair cells is frequency-specific

The inner ear is capable of highly selective frequency discrimination. This is achieved not only by the travelling wave of the basilar membrane in the cochlear partition, but also by the active participation of nonlinear and vulnerable elements that enhance frequency selectivity. It has been shown that isolated mammalian outer hair cells respond with a change in length when subjected to sound stimulation at a fixed frequency. Here we investigate the motile behaviour of isolated cells when the stimulus frequency is varied between 200 and 10,000 Hz. By varying the frequency and the intensity of the tone, it is possible to obtain 'tuning curves' for the motile response. We demonstrate that the cell body of solitary hair cells, free from contact with the basilar membrane, shows a sharply tuned motile behaviour. We suggest that frequency selectivity in the organ of Corti is amplified by the tuned motility of the cell body of outer hair cells.     

TRPA1 is a candidate for the mechanosensitive transduction channel of vertebrate hair cells

Mechanical deflection of the sensory hair bundles of receptor cells in the inner ear causes ion channels located at the tips of the bundle to open, thereby initiating the perception of sound. Although some protein constituents of the transduction apparatus are known, the mechanically gated transduction channels have not been identified in higher vertebrates. Here, we investigate TRP (transient receptor potential) ion channels as candidates and find one, TRPA1 (also known as ANKTM1), that meets criteria for the transduction channel. The appearance of TRPA1 messenger RNA expression in hair cell epithelia coincides developmentally with the onset of mechanosensitivity. Antibodies to TRPA1 label hair bundles, especially at their tips, and tip labelling disappears when the transduction apparatus is chemically disrupted. Inhibition of TRPA1 protein expression in zebrafish and mouse inner ears inhibits receptor cell function, as assessed with electrical recording and with accumulation of a channel-permeant fluorescent dye. TRPA1 is probably a component of the transduction channel itself.     

微量元素锰与肺癌的关系

本文对锰含量的测定表明:肺癌患者发锰含量显著低于对照者(P<0.01)。在动物诱癌实验中观察到,随着肿瘤的发生和发展,肝、肺中锰含量降低,而肿瘤部位锰含量则升高,提示锰含量低可能是肺癌发病的结果。     

Mammalian cochlear supporting cells can divide and trans-differentiate into hair cells

Sensory hair cells of the mammalian organ of Corti in the inner ear do not regenerate when lost as a consequence of injury, disease, or age-related deafness. This contrasts with other vertebrates such as birds, where the death of hair cells causes surrounding supporting cells to re-enter the cell cycle and give rise to both new hair cells and supporting cells. It is not clear whether the lack of mammalian hair cell regeneration is due to an intrinsic inability of supporting cells to divide and differentiate or to an absence or blockade of regenerative signals. Here we show that post-mitotic supporting cells purified from the postnatal mouse cochlea retain the ability to divide and trans-differentiate into new hair cells in culture. Furthermore, we show that age-dependent changes in supporting cell proliferative capacity are due in part to changes in the ability to downregulate the cyclin-dependent kinase inhibitor p27(Kip1) (also known as Cdkn1b). These results indicate that postnatal mammalian supporting cells are potential targets for therapeutic manipulation.     

冠心病患者头发锌铜硒等微量元素测定

应用催化极谱法分析34例冠心病患者头发中铜、锌、锰、硒及铬的含量,并与30例年令相近的健康成人对照,结果冠心病患者头发中微量元素铜含量高于对照组,硒、锰及铬的含量明显低于对照组,(p值<0.01)两组间有显著性差异,认为体内微量元素铜高,低硒、低锰、低铬可能与冠心病有关。