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1.
为了直接观察微波对人类生精细胞作用的远期效应,并了解微波节育的安全性和可逆性,本文对30名微波节育志愿受试者,在停止微波照射2年后,用光镜和扫描电镜对其精液标本进行了形态学观察,并统计畸形精子的比率.光镜下,15名志愿者的畸形精子率,范围为8.9%~27.0%,平均为17.6%±5.1%.扫描电镜下,另15名志愿者的畸形精子率,范围是17.5%~33.7%,平均为24.8%±4.6%.光镜下6名同龄的正常生育力男性的畸形精子率,范围为6.1%~15.3%,平均为9.7%±3.4%.志愿者与正常生育力男性之间的光镜下畸形精子率差异十分显著(P<0.01),但均在正常范围之内.结果显示在停止微波照射2年以后,志愿者的生精作用已基本恢复正常..  相似文献   

2.
p38蛋白激酶在热损伤诱导单核细胞Raw264.7凋亡中的作用   总被引:5,自引:0,他引:5  
为探讨p38蛋白激酶在热损伤诱导单核细胞株Raw 264.7凋亡中的调控作用.应用流式细胞检测术、透射电镜技术、DNA 凝胶电泳、Western blot、激酶活性测定检测p38蛋白激酶在热损伤诱导细胞凋亡中的作用.结果显示,热损伤后5 m in,p38即被激活,30 m in 时达到最高水平,然后逐渐下降,2 h 达基底水平;热损伤后3 h 细胞凋亡率开始明显增高,p38蛋白激酶活性增高是细胞凋亡发生之前的事件;进一步观察了p38特异性抑制剂FHPI对细胞凋亡的影响,发现FHPI可以抑制热损伤诱导的细胞凋亡.上述结果提示,p38参与介导热损伤诱导的Raw 264.7细胞凋亡.  相似文献   

3.
罗非鱼内耳形态结构研究   总被引:2,自引:1,他引:1  
罗非鱼内耳器官结构与典型硬骨鱼的内耳结构一致。球状囊呈椭圆体状,其耳五充满整个囊体,耳石上有明显的中央沟,中央沟在形态上与球状囊听斑一致;听囊呈圆形,听囊耳五约占整个听囊一半,耳石较薄且较透明,有明显外缘区和中央区之分;椭圆囊呈不规则椭球体状,其耳石占椭圆囊的较小部分,耳石表面粗糙。罗非鱼耳石膜为一层胶质膜,位于耳石和听斑之间,并触及所有毛细胞,膜有大量小孔,小孔处恰为毛细胞的纤毛束伸入,纤毛束透过小孔触及到耳石。扫描电镜观察表明,罗非鱼内耳听斑也由毛细胞和支持细胞组成,听斑表面有大量具一定分布规律的纤毛束。罗非鱼内耳听觉器官主要有三种纤毛束类型:F_1、F_2和F_3型。按照纤毛束的取向一致性,球状囊听斑划分三个区;听囊听斑和椭圆囊听斑均划分两个区。  相似文献   

4.
豚鼠耳蜗离体外毛细胞的膜电位和离子电流   总被引:1,自引:0,他引:1  
利用膜片钳技术对分离的豚鼠耳蜗外毛细胞进行了研究,结果表明:(1)新分离的正常OHC呈术状,胞膜光滑,胞核位于底部,静纤毛由顶端表皮板伸出,4小时内形态无明显变化。(2)全细胞电压钳记录结合通道阻断剂实验表明,OHC膜电流主要由电压依赖性钾离子流组成。(3)利用全细胞记录方式得到的OHC静息电位值为-26±9mV.  相似文献   

5.
本文应用光镜和电镜组化方法,对胚胎晚期至生后早期的 Wistar 大鼠气管上皮细胞Ca~(2+)-ATPase 的动态变化进行了观察。结果证实在胚胎期气管上皮细胞侧面膜和表面膜及纤毛细胞的纤毛干处有 Ca~(2+)-ATPase 活性反应产物,提示胚胎期气管上皮细胞之间可能已存在与气管上皮细胞分化、发育密切相关的钙;在生后早期,纤毛细胞的基粒和纤毛小根处出现活性 Ca~(2+)-ATPase,表明生后早期已出现纤毛运动,其对廓清气道具有重要意义。  相似文献   

6.
本文对豚鼠耳蜗离体外毛细胞的细胞活性及底侧膜处电压依赖性钾离子通道进行了研究,结果表明:(1)离体外毛细胞悬液保存在4℃时,可延长存活时间达7h以上。(2)外毛细胞的静息电位:应用电流钳方法,在刚形成全细胞方式时其细胞内静息电位为-73.7±6.9mV,2min后为-94.8±4.1mV(x±s,n=10)。(3)全细胞方式记录到的电压依赖性外向K+电流是由快钾电流和延迟整流钾电流两部分组成,快钾电流的激活电位为-60~-50mV,延迟整流钾电流的激活电位为-40~-30mV,电流-电压关系曲线呈“S形上升”趋势。外向K+电流被TEA(20mmol/L)阻断后,可观察到一种电压依赖性内向电流  相似文献   

7.
扬子鳄内耳的组织结构及其早期胚胎发育   总被引:3,自引:0,他引:3  
扬子鳄内耳的椭圆囊与球囊间以有前、后半规管形成的总脚处均存在瓣膜,半规管、壶腹嵴及囊斑的组织结构与其他爬行类动物相似。扬子鳄耳蜗伸长且弯曲,由典型的三个腔即前庭阶、鼓足干劲阶的中阶(膜蜗管)构成;基膜中间厚、两侧薄,在耳蜗腹端较宽,向背端逐渐变窄;柯蒂氏器由支持细胞和两型毛细胞(高毛细胞和矮毛细胞)组成;前庭膜厚且高度血管化。在平均约28℃孵化温度下,孵化后第2天胚胎耳板凹陷呈浅杯状;第6天凹陷口  相似文献   

8.
本文应用免疫细胞方法,研究大鼠生后4天、7天、14天、30天、2个月和3个月睾丸中S-100蛋白的分布和变化规律。结果表明:S-100蛋白染色反应位于睾丸间质细胞,直到生后30天才出现阳性细胞,数量少,着色浅,而2月龄和3月龄大鼠睾丸S-100蛋白阳性细胞数量多,着色深。提示S-100蛋白可能参与间质细胞的合成和分泌睾酮过程。  相似文献   

9.
为了探讨听觉损伤与毛细胞损伤的关系,本实验比较了噪声暴露后豚鼠皮层听阈及其与基底膜单位长度上毛细胞损伤率的关系。暴露声源中心频率1000Hz,为1/3倍频程的窄带噪声。强度为136dB作用1小时。108dB每天暴露1小时,5天/周连续1个月。结果表明,毛细胞损伤呈灶性,损伤部位与周围界线十分分明。毛细胞损伤在豚鼠间及左右耳间均存在相当程度的个体差异。136dB暴露,毛细胞损伤最重的部位在基底膜1.5转到2.5转之间,符合1000Hz声音在基底膜的最大振动范围。108dB的损伤部位局限在1.5转,其范围及程度明显轻于136dB。136dB造成的听阈偏移高于108dB,尤其在4、8 KHz高频听阈偏移最明显,但耳蜗底转毛细胞多无明显损伤。  相似文献   

10.
应用真彩色图象分析仪,对15例DU、GU和Con组患者,非病变区胃窦粘膜幽门腺,151个β-内啡肽样免疫反应细胞(β-EP细胞)的12个参数进行检测及每组75个单位面积(5000μm2)的β-EP细胞进行计数。β-EP细胞的周长、面积、长径、短径和平均体积数值是DU组<GU组<Con组,各组间两两相比,均呈高度显著性差异,P<0.01。在DU与Con组、或GU与Con组之间,比表面、平均截距、平均表面积和平均直径数值相比,亦呈高度显著性差异,P<0.01。DU组β-EP细胞数增高,与GU或Con组分别相比,均呈高度显著性差异,P<0.01。在三组中,β-EP细胞的比表面积、平均截距、平均表面积、平均直径数值和细胞数的显著性差异率在60%以上,周长、面积、长径、短径和平均体积数值达100%。本文首次建立了DU、GU和Con组非病变区胃窦粘膜幽门腺β-内啡肽细胞的二维和三维形态计量学参数数据,提示β-EP细胞参与了溃疡病的内分泌调控活动。  相似文献   

11.
In the mammalian cochlea, stereociliary bundles located on mechanosensory hair cells within the sensory epithelium are unidirectionally oriented. Development of this planar polarity is necessary for normal hearing as stereociliary bundles are only sensitive to vibrations in a single plane; however, the mechanisms governing their orientation are unknown. We report that Wnt signaling regulates the development of unidirectional stereociliary bundle orientation. In vitro application of Wnt7a protein or inhibitors of Wnt signaling, secreted Frizzled-related protein 1 or Wnt inhibitory factor 1, disrupts bundle orientation. Moreover, Wnt7a is expressed in a pattern consistent with a role in the polarization of the developing stereociliary bundles. We propose that Wnt signaling across the region of developing outer hair cells gives rise to planar polarity in the mammalian cochlea.  相似文献   

12.
Sensory epithelia of the inner ear require a coordinated alignment of hair cell stereociliary bundles as an essential element of mechanoreceptive function. Hair cell bundle alignment is mediated by core planar cell polarity (PCP) proteins, such as Vangl2, that localize asymmetrically to the circumference of the cell near its apical surface. During early phases of cell orientation in the chicken basilar papilla (BP), Vangl2 is present at supporting cell junctions that lie orthogonal to the polarity axis. Several days later, there is a striking shift in the Vangl2 pattern associated with hair cells that reorient towards the distal (apical) end of the organ. How the localization of PCP proteins transmits planar polarity information across the developing sensory epithelium remains unclear. To address this question, the normal asymmetric localization of Vangl2 was disrupted by overexpressing Vangl2 in clusters of cells. The BP was infected with replication-competent retrovirus encoding Vangl2 prior to hair cell differentiation. Virus-infected cells showed normal development of individual stereociliary bundles, indicating that asymmetry was established at the cellular level. Yet, bundles were misoriented in ears infected with Vangl2 virus but not Wnt5a virus. Notably, Vangl2 misexpression did not randomize bundle orientations but rather generated larger variations around a normal mean angle. Cell clusters with excess Vangl2 could induce non-autonomous polarity disruptions in wild-type neighboring cells. Furthermore, there appears to be a directional bias in the propagation of bundle misorientation that is towards the abneural edge of the epithelium. Finally, regional bundle reorientation was inhibited by Vangl2 overexpression. In conclusion, ectopic Vangl2 protein causes inaccurate local propagation of polarity information, and Vangl2 acts in a non-cell-autonomous fashion in the sensory system of vertebrates.  相似文献   

13.
The planar cell polarity (PCP) pathway, a noncanonical Wnt signaling pathway, is crucial for embryonic development in all animals as it is responsible for the regulation of coordinated orientation of structures within the plane of the various epithelia. In the mammalian cochlea, one of the best examples of planar polarity in vertebrates, stereociliary bundles located on mechanosensory hair cells within the sensory epithelium are all uniformly polarized. Generation of this polarity is important for hair cell mechanotransduction and auditory perception as stereociliary bundles are only sensitive to vibrations in their single plane of polarization. We describe the two step developmental process that results in the generation of planar polarity in the mammalian inner ear. Furthermore, we review evidence for the role of Wnt signaling, and the possible generation of a Wnt gradient, in planar polarity.  相似文献   

14.
The supramolecular organization of the plasma membrane of apical cells in shoot filaments of the marine red alga Porphyra yezoensis Ueda (conchocelis stage) was studied in replicas of rapidly frozen and fractured cells. The protoplasmic fracture (PF) face of the plasma membrane exhibited both randomly distributed single particles (with a mean diameter of 9.2 ± 0.2 nm) and distinct linear cellulose microfibril-synthesizing terminal complexes (TCs) consisting of two or three rows of linearly arranged particles (average diameter of TC particles 9.4 plusmn; 0.3 nm). The density of the single particles of the PF face of the plasma membrane was 3000 μm?2, whereas that of the exoplasmic fracture face was 325 μm?2. TCs were observed only on the PF face. The highest density of TCs was at the apex of the cell (mean density 23.0 plusmn; 7.4 TCs μm?2 within 5 μm from the tip) and decreased rapidly from the apex to the more basal regions of the cell, dropping to near zero at 20 μm. The number of particle subunits of TCs per μm2 of the plasma membrane also decreased from the tip to the basal regions following the same gradient as that of the TC density. The length of TCs increased gradually from the tip (mean length 46.0 plusmn; 1.4 nm in the area at 0–5 μm from the tip) to the cell base (mean length 60.0 plusmn; 7.0 μm in the area at 15–20 μm). In the very tip region (0–4 μm from the apex), randomly distributed TCs but no microfibril imprints were observed, while in the region 4–9 μm from the tip microfibril imprints and TCs, both randomly distributed, occurred. Many TCs involved in the synthesis of cellulose microfibrils were associated with the ends of microfibril imprints. Our results indicate that TCs are involved in the biosynthesis, assembly, and orientation of cellulose microfibrils and that the frequency and distribution of TCs reflect tip growth (polar growth) in the apical shoot cell of Porphyra yezoensis. Polar distribution of linear TCs as “cellulose synthase” complexes within the plasma membrane of a tip cell was recorded for the first time in plants.  相似文献   

15.
The development of the saccule of the inner ear in the toadfish was studied using light and scanning electron microscopy. Development was studied from the early embryo (2-3 days postfertilization), when the otocyst first forms, to the early-aged juvenile when the development of the inner ear approximates that of the adult (4 weeks postfertilization). The ultrastructural features examined included the morphological sequence of ciliary bundle growth, the development of orientation patterns of the ciliary bundles, and the relation of the ultrastructural development to overall gross development. Gross development may be divided into four distinct morphological stages. Stage I encompasses the time from initial formation of the otocyst until the start of stage II, which is the stage when the pars inferior begins migrating ventrally. In stage III the pars inferior continues to elongate ventrally. Stage IV starts when the pars inferior elongates in a rostral and caudal direction. The ear attains its adult shape in stage IV. The differentiation of the sensory cells begins during stage I. During the early part of stage I, a small cilium is found on the apical surface of each cell throughout the otocyst. In the middle and late periods of stage I, a few microvillous buds add to the surface of the cells that already have a kinocilium. These early ciliary bundles are clustered on the rostral-ventral and caudal walls of the otocyst. There is no clear patterning to the orientation of these ciliary bundles. In stage II the ventral stretching of the labyrinth wall causes a spreading of the clustered bundles along the ventral and medial walls of the pars inferior. The orientation of the ciliary bundles has no distinct pattern. In stage III the orientations of the ciliary bundles appear adultlike, although there are so few ciliary bundles that it is difficult to make a definite determination. During stage IV, hair cells with an adultlike horizontal and vertical orientation pattern are found on the rostral and caudal sections of the saccular macula, respectively. The transition region lying between these areas has ciliary bundles with various orientations.  相似文献   

16.
惊厥后大鼠海马神经再生与凋亡的动态变化   总被引:1,自引:0,他引:1  
探讨惊厥持续状态(status convulsion,SC)后大鼠海马神经再生与凋亡的动态变化。建立成年Wistar鼠30minSC模型,在SC后1天至56天的6个时间点上处死动物,处死前1天均腹腔注射5-溴2-脱氧尿嘧啶核苷(5-bromo-2-deoxyuridine,BrdU);采用免疫组织化学方法动态检测BrdU、nestin的表达,确定神经干细胞增殖水平;双重荧光染色标记nestin/TUNEL,确定新生神经干细胞存活时间。与对照组相比,BrdU阳性细胞数目于SC后第7天在CA1区达增殖高峰,28天降至正常水平;于SC后第28天在齿状回达增殖高峰,56天降至正常水平;在SC后第7天,CA3区有大量的BrdU阳性细胞;BrdU和nestin阳性细胞数目无统计学差异。在SC后的前3天,CA1区新增殖的神经细胞呈TUNEL阳性;齿状回新增殖细胞始终表现TUNEL阴性。上述结果提示:SC后能激活自体神经干细胞原位增殖,并且部分新生细胞向损伤区域迁移。  相似文献   

17.
《The Journal of cell biology》1988,107(6):2563-2574
By direct counts off scanning electron micrographs, we determined the number of stereocilia per hair cell of the chicken cochlea as a function of the position of the hair cell on the cochlea. Micrographs of thin cross sections of stereociliary bundles located at known positions on the cochlea were enlarged and the total number of actin filaments per stereocilium was counted and recorded. By comparing the counts of filament number with measurements of actin filament bundle width of the same stereocilium, we were able to relate actin filament bundle width to filament number with an error margin (r2) of 16%. Combining this data with data already published or in the process of publication from our laboratory on the length and width of stereocilia, we were able to calculate the total length of actin filaments present in stereociliary bundles of hair cells located at a variety of positions on the cochlea. We found that stereociliary bundles of hair cells contain 80,000-98,000 micron of actin filament, i.e., the concentration of actin is constant in all hair cells with a range of values that is less than our error in measurement and/or biological variation, the greatest variation being in relating the diameters of the stereocilia to filament number. We also calculated the membrane surface needed to cover the stereocilia of hair cells located throughout the cochlea. The values (172-192 micron 2) are also constant. The implications of our observation that the total amount of actin is constant even though the length, width, and number of stereocilia per hair cell vary are discussed.  相似文献   

18.
Summary A combination of direct fluorescence and indirect immunofluorescence microscopy has been used to compare the distribution of the acetylcholine receptor with the distribution of major cytoskeletal and extracellular matrix components during electrocyte differentiation in the electric organs of Torpedo marmorata. Laminin, fibronectin and extracellular matrix proteoglycan are always more extensively distributed around the differentiating cell than the acetylcholine receptor-rich patch that forms on the ventral surface of the cell. The distribution of acetylcholinesterase within the ventral surface of the differentiating electrocyte closely resembles the distribution of the acetylcholine receptor. Areas of apparently high acetylcholine receptor density within the ventrally forming acetylcholine receptor-rich patch are always areas of apparently high extracellular matrix proteoglycan density but are not always areas of high laminin or fibronectin density. Desmin levels appear to increase at the onset of differentiation and desmin initially accumulates in the ventral pole of each myotube as it begins to form an electrocyte. During differentiation F-actin-positive filament bundles are observed that extend from the nuclei down to the ventrally forming acetylcholine receptorrich patch. Most filament bundles terminate in the acetylcholine receptor-rich region of the cell membrane. Electronmicroscopic autoradiography suggests that the filament bundles attach to the membrane at sites where small acetylcholine receptor clusters are found. The results of this study suggest that, out of the four extracellular matrix components studied, only the distribution of acetylcholinesterase (which may be both matrix- and membrane-bound at this stage) closely parallels that of the acetylcholine receptor, and that F-actin filament bundles terminate in a region of the cell that is becoming an area of high acetylcholine receptor density.Abbreviations ACHR nicotinic acetylcholine receptor - ACHE acetylcholinesterase - BSA bovine serum albumin - EMPG extracellular matrix proteoglycan fraction - FITC fluorescein isothiocyanate - FN fibronectin - LN laminin - TBS Tris-HCl-buffered saline - SDS PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis  相似文献   

19.
 We have studied the phenotypic changes in regenerating smooth muscle (SM) tissue of detrusor muscle after local application of a necrotizing, freeze–thaw injury to the serosal surface of rabbit bladder. Bromo-deoxyuridine (BrdU) incorporation and immunofluorescence studies were performed on bladder cryosections from day 2 up to day 15 after surgery with monoclonal antibodies specific for some cytoskeletal markers [desmin, vimentin, non-muscle (NM) myosin] and for SM-specific proteins (α-actin, myosin, and SM22). Four days after lesion, some clls incorporated in regenerating SM bundles are BrdU positive, but all display a phenotypic pattern identical to that of the interstitial, highly proliferating cells, i.e., expression of vimentin. By days 7–15 the differentiation profile of regenerating SM returns to that of uninjured SM tissue (appearance of desmin, SM-type α-actin, and SM myosin). A chemical denervation achieved by 6-hydroxydopamine treatment for 2 weeks induces the formation of vimentin/SM α-actin/NM myosin/SM22-containing myofibroblasts in the interstitial, fibroblast-like cells of uninjured bladder. In the bladder wall, alteration of reinnervation during the regenerating SM process produces: (1) in the outer region, the activation of vimentin/SM α-actin/desmin myofibroblasts in the de novo SM cell bundles; and (2) in the inner region of bladder, including the muscularis mucosae, the formation of proliferating, fully differentiated SM cells peripherally to newly formed SM cell bundles. These findings suggest that: (1) the de novo SM tissue formation in the bladder can occur via incorporation of interstitial cells into growing SM bundles; and (2) the alteration of reinnervation during the regenerating process induces a spatial-specific differentiation of interstitial myofibroblasts in SM cells before SM cell bundling. Accepted: 14 May 1997  相似文献   

20.
Unstimulated and PWM-stimulated lymphocytes from normal human peripheral blood, cord blood, peripheral blood of patients with panhypogammaglobulinemia and selective IgA deficiency, as well as human lymphoblastoid cell lines were examined for their ability to bind secretory component (SC) on the surface and in the cytoplasm. SC binding was not detected on the cell surface at any stage of differentiation in these cells. However, binding of SC was detected in the cytoplasm of 2.3% of normal peripheral blood lymphocytes cultured in the presence of PWM for 6 to 7 days, and in two IgA producing lymphoblastoid cell lines. The capability of lymphoid cells to bind SC was not concurrent with J chain production. Although IgA was detected in the cytoplasm of PWM-stimulated lymphocytes from IgA-deficient patients, these cells did not bind SC. The failure to detect surface receptors indicates that SC is not a probable factor determining the homing of IgA precursor cells into exocrine tissues.  相似文献   

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