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find Keyword "光感受器" 33 results
  • 视网膜光感受器细胞分化过程中基因调控机制的研究进展

    哺乳类动物的视网膜光感受器细胞包括视杆细胞和视锥细胞。这两种细胞的数量在视网膜中按一定比例和特定的空间分布,其分化发育的时间存在明显差异,视锥细胞的发育早于视杆细胞。两种细胞均来源于具有同一多向分化潜能的视网膜光感受器前体细胞,在光感受器细胞特异性转录因子的调控作用下分化为不同的光感受器细胞亚型。这一分化过程主要受7种重要的转录因子所调控。深入了解这些转录因子对视网膜光感受器细胞分化的功能和调控机制,将有助于我们对视网膜光感受器细胞分化过程中关键机制的全面理解。

    Release date:2016-09-02 05:21 Export PDF Favorites Scan
  • 眼球钝挫伤致视网膜感光细胞层断裂一例

    Release date:2016-09-02 05:18 Export PDF Favorites Scan
  • Effects of local foveal photoreceptor defect on visual acuity

    Objective To observe the effects of local macular foveal photoreceptor defects on visual acuity.Methods Thirty-one patients (31 eyes) with photoreceptor defect in macular fovea (case group) diagnosed by spectral domain optical coherence tomography (SD-OCT) and 30 patients (30 eyes) age- and diopter- matched normal subjects (control group) were enrolled in this study. There were 22 eyes with full photoreceptor defects and 9 eyes with outer segment defects in case group. All subjects were examined for best corrected visual acuity (BCVA), slit-lamp microscopy, direct ophthalmoscope and SD-OCT. Independent sample t-test was used to compare central foveal thickness (CFT) between case group and control group. Difference of logMAR BCVA, CFT, maximum width and height of photoreceptor defects, defected area and residual retinal thickness in macular between patients with full photoreceptor defects and outer segment defects were also compared.Results The CFT of case group and control group were (225.32plusmn;19.70),(240.02plusmn;10.70) mu;m, the difference was not statistically significant (t=-1.96, P>0.05). In full photoreceptor defects and outer segment defects patients, the mean logMAR BCVA were 0.22plusmn;0.31, 0.32plusmn;0.43; the mean CFT were (224.09plusmn;20.57), (228.33plusmn;18.17) mu;m; the maximum width of photoreceptor defects were (131.32plusmn;108.18), (143.22plusmn;66.93) mu;m; the mean defected area were (0.022plusmn;0.054), (0.019plusmn;0.019) mm2; the mean maximum height of photoreceptor defects were (77.41plusmn;6.62), (44.89plusmn;4.26) mu;m; the mean residual retinal thickness were (87.00plusmn;20.31), (128.33plusmn;23.54) mu;m respectively. There was no statistical significance between full photoreceptor defects and outer segment defects patients in the mean logMAR BCVA, CFT, maximum width of photoreceptor defects and defected area (t=-0.76, -0.538, -0.305, 0.166; P>0.05), but there were significant difference in mean maximum width of photoreceptor defects and residual retinal thickness (t=12.72, -4.91;P<0.05). Conclusions The local photoreceptor defects in macular fovea can lead to decrease of visual acuity. The wider the photoreceptor defects, the worse the visual acuity.

    Release date:2016-09-02 05:26 Export PDF Favorites Scan
  • Gene transfection into retinal pigment epithelial cells and photoreceptors using in vivo electroporation

    Objective  To investigate the feasibility of gene transfection into retinal pigment epithelial (RPE) cells and photoreceptors (PRs) in vivo electroporation. Methods  A total of 147 Sprague-Dawley (SD) rats were divided into 5, 10, 15, 20, 25, 30 and 35 V group according to different voltage. The right eyes of rats underwent the injection of eukaryotic expressive plasmid of enhanced green fluorescent protein (EGFP) pEGFP-N1 into subretinal space as experimental eyes; the left eyes were injected with TE buffer as control eyes. Each group was divided into RPE and RP subgroups according to different transfection direction. There were same parameters of 99 ms pulse width, 0.5 s pulse interval and 5 consecutive pulses except different voltage in groups. With a negative charge in the electric field was transfected into RPE cell layer, reverse electrode set to be transfected into PR cell layer. Retina mounts were made on seven days after transfection and the fluorescence of EGFP was photographed by fluorescent microscope. The expression of EGFP mRNA and protein were detected by reverse transcription polymerase chain reaction technique (RT-PCR) and Western blot.Results  On seven days after transfection, in RPE subgroups, there were no specific fluorescence expressions in RPE cell layer and retina mounts of control eyes, while there were fluorescence expressions in experimental eyes. Western blot showed that the grayscale ratio of EGFP protein and beta;actin protein bands rose with the increased voltage. RT-PCR showed that each group produced positive amplification bands, and the relative ratio of gray level of EGFP mRNA and GADPH mRNA amplified bands gradually increased with the increased voltage.Conclusion  Electroporation is an effective method for gene delivery into RPE cells in vivo.

    Release date:2016-09-02 05:40 Export PDF Favorites Scan
  • Protective effects of recombinant erythropoietin on photoreceptor cells in rat with retinal detachment

      Objective To investigate the protective effect of recombinant erythropoietin (EPO) on the photoreceptor cells in rat with retinal detachment (RD).Methods One hundred and sixtytwo normal male rats were randomly divided into normal control (NC) group, RD model group, RD+phosphate buffer solution (RD+PBS) group, RD+EPO 100 ng group, RD+EPO 200 ng group and RD+EPO 400 ng group. Three days after RD, activated caspase3 and bclXL were detected by Western blot and/or immunofluorescence, and apoptosis were measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick-end labeling(TUNEL). Fourteen and 28 days and two months after RD, the outer nuclear layer (ONL)thickness was measured by histopathologic method.Results Western bolt indicated that the protein level of activated caspase-3 and bcl-XL between six groups were statistically significant(F=35.96, 30.75;P<0.01). The number of TUNEL positive cells and activated caspase-3 positive cells are consistent with each other in different groups. Fourteen days and two months after RD,the differences of ONL thickness between six groups were statistically significant(F=21.52,96.25;P<0.01).Conclusion Supplement of EPO after RD can alleviate apoptosis by inhibiting of the caspase-3 activity and increasing the expression of bcl-XL,thus exerts protective effect on photoreceptor cells.

    Release date:2016-09-02 05:41 Export PDF Favorites Scan
  • 视网膜变性后的重构

    视网膜重构是指各种原因导致的光感受器变性、死亡,随后视网膜上所有神经元和非神经元细胞发生一系列病理改变,最终视功能完全丧失的一系列视网膜组织变化过程;以视网膜神经元死亡、细胞迁移和微神经瘤的形成,视觉信号去传入阻滞,产生异常的视觉输入为特征。认识视网膜神经元重构时结构、微环境和电生理变化的过程,阐明变性视网膜突触重构的机制,将为中晚期替换坏死或凋亡的细胞,挽救和恢复视功能的治疗提供实验依据和理论基础。

    Release date:2016-09-02 05:41 Export PDF Favorites Scan
  • Intervention effect of the tetramethylpyrazine on the rds mice with retinitis pi gmentosa

    Objective:To observe the intervention effect of the tetra methylpyraz ine on the rds mice with retinitis pigmentosa. Methods:A total of 84 rds mice were randomly divided into 2 groups, with 42 mice in each group. The mice in the experimental group underwent intraperitoneal cavity injection with hydrochlor i c tetramethylpyrazine (80 mg/kg, twice per day) at the date of birth and till 35 days after birth, whereas the normal saline was injected into the intraperito n eal cavity of rats in the control group. The mice were sacrificed 0, 3, 7, 14, 2 1, 28, 35 days after birth, and the eyeballs were enucleated for the routine pat hologic examination with the light microscope. The apoptosis of photoreceptor ce ll nuclei was detected by terminal deoxynucleotidyl transferasemediated dUTP n i ck endlabeling (TUNEL) technigue and the expression of bcl2 in retina was de tect by immunohistochemistry method. Results:The results of li ght microscopy s howed that the layer number of retinal photoreceptor cell nuclei with tetramethy lpyrazine treatment was increased 14, 21, 28, 35 days after the treatment compar ed with that in the control group(P<0.01). The results of electron-micro scope suggested that tetramethylpyrazine might reduce lesions in the photoreceptor cells and the destruction of the disc member, mitochondrion,and outer limiting me mbrane in the photoreceptor outer segment in rds mice. The apoptosis of the phot oreceptor cell nuclei reduced in rds mice 3, 7, 14, 21, 28 and 35 days after the treatment compared with that in the control group (P<0.01). The express ion of bcl-2 in the matrix of retinal photoreceptor cell nuclei and its inner and o u ter segments increased significantly in rds mice 3,7, 14, 21, 28 and 35 days af ter the treatment (P<0.05). Conclusions:Tetramethylpyra zine might reduce ret inal photoreceptor apoptosis by upregulating the expression of bcl-2 in the m at rix of retinal photoreceptor cell nuclei or its inner and outer segments in rds mice.

    Release date:2016-09-02 05:48 Export PDF Favorites Scan
  • Distribution of human retinal photoreceptor cells at the posterior pole of the ocular fundus

    Objective To observe the distribution of human photoreceptor cells at the posterior pole, detect the change of density of the cells affected by eccentricity, and analyze the relationship between the density distribution and the visual sensitivity. Methods Twenty human eye cups with the cornea removed were fixed in 4% polyformaldehyde for 1-4 weeks, and the retinal mounts were observed by differential interference contrast microscope to reveal the retinal cellular configuration and density. The inner segments of photoreceptor cells were first observed from the center to the temporal peripheral part of the retinal mounts. Results The highest density of visual cone cells was at the central fovea (134 000-267 000/mm2, mean 198 090/mm2; CV value:18.2%). The density and individual variation decreased rapidly in the peripheral area. The high density area of rod cells was at the 4 mm of the eccentricity, with the highest value of 72 610-182 350/mm2 and with the high density between 3 and 5 mm. Conclusions The inner segment of photoreceptor cells was monolayer, which may tell the cellular absolute value. The high density of retinal cone cells at the central fovea provide the basis of sensitive central visual acuity, which relates to the individual variation and development. The rod cells have the peak density at the eccentricity with 4 mm, and this area has the greatest sensitivity of dim vision.

    Release date:2016-09-02 05:48 Export PDF Favorites Scan
  • Apoptosis of photoreceptor cell in experimental model of retinal detachment in mice

    Objective To investigate the apoptosis of photoreceptor cells in experimental model of retinal detachment in mice. Methods Thirty-six adult C57Bl/6J mice were divided into 2 groups: retinal detachment model was set up in the left eyes of 18 mice by subretinal injection with 1.4% sodium hyaluronate in the experimental group, while the left eyes of other 18 mice underwent scleral puncture only as the control. The retinal sections were stained with histochemical and immunofluorescent staining and examined by confocal microscopy 1,3,7 and 28 days after injection. eye enucleated, and retinal sections studied by histochemistry, immunofluorescence labeling, and confocal microscopy. Rods, cones, and apoptotic cells were labeled by antibodies of anti-rod and anti-cone cells, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL), respectively. Photoreceptor cell apoptosis and cell loss were assessed quantitatively by counting both surviving and apoptotic rod and cone cells. Results TUNEL-positive cells were only found in the outer nuclear layer (ONL) of the detached portion of the retina, which were detected at the 1st day after the detachment. The apoptosis of the cells reached the peak at the 3rd day and decreased sharply after 7 days. Photoreceptor cell loss of both rod and cone cells followed a similar time course after retinal detachment. Conclusion Apoptosis is a major pathological degeneration of photoreceptor cell death after retinal detachment. (Chin J Ocul Fundus Dis, 2006, 22: 124-127)

    Release date:2016-09-02 05:51 Export PDF Favorites Scan
  • Electrophysiological response in rabbits with normal and injured photoreceptor due to subretinal implantation of chip

    Objective To observe the changes of electrophysio logical results in rabbits with normal and injured photoreceptor due to subretinal implantation of chip. Methods Photoreceptor damage was induced by injection with NaIO3 solution in 22 out of 30 rabbits. A chip with the diameter of 3 mm made by the array composed of 90 microelectrodes photodiode and conjoint electrode was implanted into subretinal space or choroid of the right eyes of 22 rabbits with photoreceptor and 4 normal rabbits, and the left eyes were the control. The examinations of local flash-visual evoked potential (F-VEP), local flash-electroretinogram (F-ERG), full-field F-ERG and full-filed F-VEP were measured respectively.Another 4 rabbits underwent biocular extirpation for path ological examination . Results In 22 rabbits with photo-receptor damage, the amplitude of the main wave of local ERG was obviously higher in 11 eyes with chips than that in the control ones, and was also higher in 2 eyes with chips of the 4 mormal rabbits than that in the control eyes. No wave was found in an eye with retinal hole on the surface of the chip. The repeataility of main amplitude of local-VEP and full-field F-VEP is not satisfactory; no significant changes were observed between chip-implanted eyes and the control eyes examined by full-filed F-ERG. Conclusion The implanted chip may stimulate local retina and induce electrical activities after stimulated by light. (Chin J Ocul Fundus DIs, 2006, 22: 324-327)

    Release date:2016-09-02 05:51 Export PDF Favorites Scan
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