Mi Yan

Sichuan University, Chengdu, Sichuan Sheng, China

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Publications (8)0 Total impact

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    ABSTRACT: To constructed eukaryotic expressing siRNA sections targeting human and rat Rac1 and to observe their effects on Rac1 gene expression in HeLa cell line. siRNA sequences were designed and synthesized targeting human and rat's Rac1 mRNA, and then directionally cloned into pSUPER plasmid. The recombinant vectors were confirmed by enzyme digestion analysis and DNA sequencing. The recombinant vectors were transfected into HeLa cell line and the transfection rate was evaluated with fluorescence microscope. The effects of the recombinants on Rac1 at mRNA levels were observed by RT-PCR. Three siRNA expressing recombinants and corresponding negative control vector were constructed and transfected into HeLa cell successfully. Rac1 transcript was reduced significantly in three transfectants. The construction of eukaryotic expression vectors expressing siRNA sections targeting Rac1 and identification successfully. This will be very helpful for further study on the function of Rac1 and it may be a useful tool in the treatment of the neovascular retinopathy.
    Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 11/2009; 40(6):969-72.
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    ABSTRACT: To establish an experimental model of choroidal neovascularization (CNV) through perimacular laser treatment in the eyes of rhesus Monkey. The experimental CNV was induced by perimacular laser injury in the eyes of 8 rhesus monkeys and confirmed by a comparison before and after the laser treatment (20 d, 34 d, 48 d) with fluorescence fundus angiography (FFA) and optical coherence tomography (OCT). Classic CNV similar to human CNV appeared in 68.8% of the laser spots. Hypofluorescence in the early phase and fluorescence leakage in the late phase were detected by the FFA. High reflect light echogenic mass and retina edema were detected by the OCT. The histopathologic examinations found proliferated fiber-vasculosa membranes in the laser burnt spots. The pathological changes lasted 48 days until the monkeys were killed. The laser induced experimental CNV in rhesus monkey has a high prevalence and stability, which maintains a long period. It is an ideal experimental model for studying the pathologic mechanism of CNV and effective treatment for CNV.
    Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 08/2008; 39(4):567-9, 574.
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    ABSTRACT: To investigate the therapeutic effects and safety of photodynamic therapy on choroidal neovascularization (CNV) of pathologic myopia. Retrospective noncomparative clinical data of 27 cases with CNV complicated from pathologic myopia (32 eyes) and treated with PDT, the parameters including the study were fundus characteristics, fluorescein fundus angiography (FFA), optic coherence tomography (OCT), and best corrected visual acuity (BCVA) before and after PDT. The mean age of 27 patients was 40.5. Five cases in the series were bilateral CNV. 29 eyes were subfoveal CNV and 3 eyes were juxtafoveal CNV. The degree of myopic was from -6D to -12D. At the final follow up, the improvement (increase >or= 2 lines) of BCVA was seen in 4 eyes (12.5%), vision acuity was stabilized (+/- 1 line) in 27 eyes (84.4%) and decreased (>or= 2 lines) in 1 eyes (3.1%). Metamorphopsia disappeared in 29 eyes (90.6%). FFA showed lacquer cracks in 12 eyes. CNV was completely closed in 17 eyes (53.1%), incompletely closed in 6 eyes (18.8% and partial closed in 9 eyes (28.1%) as demonstrated by FFA. The mean number of PDT treatment was 1.3 per eye in 27 cases. No serious local or systemic complications were encountered. PDT is a safe and effective treatment for patients with CNV of pathologic myopia, it can reduce the risk of moderate and severe vision loss and alleviate the symptoms. PDT may improve the functional visual status of patients with pathologic myopia.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 08/2007; 43(7):638-41.
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    ABSTRACT: To determine the safety and efficacy of verteporfin (visudyne) photodynamic therapy in age-related macular degeneration patients with subfoveal predominant choroidal neovascularization in China. Multicenter, open-label, non-controlled clinical study. The included patients are diagnosed AMD patients with predominant classic CNV. The included patients received verteporfin intravenously followed by 689 nm laser light administration 15 minutes after the infusion start. The patients were be followed up for 24 weeks (+/-12 days) after initial verteporfin PDT treatment. Clinical follow-up was done at the end of week 12 (+/-12 days) and week 24 (+/-12 days) after the initial treatment. Additional treatment was given after 12 weeks from initial treatment if leakage from CNV was observed on fundus fluorescein angiogram. The visual acuity with ETDRS visual chart and the retinal lesion changes were documented and compared with baseline. The adverse events both in the process of treatment and in the follow-up were recorded throughout the entire study period. Thirty-one patients (31 eyes) were included and completed the trial with verteporfin PDT treatment. During the 24 weeks of the trial, 38.7% of the treated eyes had a vision gain more than 5 letters, 83.9% of the treated eyes had less than 15 letters vision loss. At week 12 after the initial treatment, 12.9% of the treated eyes had no leakage; 61.3% of the treated eyes had leakages, but limited to the former lesion, 25.8% of the treated eyes had increased leakage. The results at week 24 after the initial treatment were similar to those at week 12. At week 24 after the initial treatment, there were only slight enlargements in the lesion size, area of retinal lesion, the lesion surrounding area, and greatest linear dimension (GLD) of the lesion, but no statistical significant difference was found between baseline and week 12 after initial treatment (P = 0.65, 0.31, 0.12, respectively). No obvious progress of the fibrosis was detected in most of the PDT treated eyes. Eleven cases of adverse events (AE) occurred in our trial and the incidence was 34.4%. Among the 11 patients with reported adverse event, 7 (21.9%) had mild adverse event; 3 (9.4%) had moderate adverse events; 1 (3.1%) had a serious adverse event. During the study period, no abnormal changes were found in most of the laboratory tests including serum and urine biochemistry, hematology and Electrocardiogram. The results of this trial showed positive efficacy of PDT with verteporfin in the treatment of predominantly subfoveal CNV secondary to AMD by reducing the risk of vision loss. The incidence of serious adverse events was only 3.1%. It is highly safe to use PDT with verteporfin in Chinese AMD patients with subfoveal predominant classical CNV.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 04/2007; 43(3):198-205.
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    ABSTRACT: To investigate the effect of blue light on apoptosis and mitochondrial permeability transition (MPT) of cultured human retinal pigment epithelium (RPE) cells in vitro. Human RPE cells were exposed to blue light (wave length 470 -490 nm). The present study consisted of three parts. Part one studied the effect of various intensities of blue light on the RPE cells. Cells were irradiated with (500+/-100) lx (group 1) , (2000+/-500) lx (group 2) and (3000+/-500)lx ( group 3) blue light, and followed by 24 hours observation. Part two studied the effect of various duration of blue light at identical intensity on the RPE cells. For the study on various subtypes of RPE cells, cells were irradiated by blue light at (2000+/-500) x for 6, 12, and 24 hours. For the study of mitochondrial membrane potential, cells were irradiated for 3, 6, and 12 hours. Part three studied cells irradiated with blue light at identical intensity and duration, but with various prolongation of post-exposure culture. The prolongation of post-exposure culture was 6, 12, 24, and 36 hours. Phototoxicity was quantified at various periods after exposure by staining of the nuclei of membrane-compromised cells, by TdT-dUTP terminal nick-end labeling (TUNEL) of apoptotic cells and by Annexin V labeling for phosphatidylserine exposure. Transmission electronmicroscopy was used to determine the ultrastructure changes of RPE cells. Mitochondrial membrane potential ( deltaPsim ) was measured by rhodamine 123 staining and subsequent flow cytometry. Cytochrome C activity was assayed by ELISA. Caspase-3 was detected by colorimetric assay. TUNEL-positive labeling cells in first group of part two study showed cell shrinkage, membrane blebbing, apoptotic body, condensation and fragmentation of chromatin. Mitochondrial swelling, extinction of inner mitochondrial membrane ridge, dilation of rough endoplasmic reticulum and increase of the lysosome were also observed in transmission electronmicroscopy. Blue light at (500 +/- 100) x intensity did not induce damage to RPE cells, but decrease of delta Psim was observed. A significant increase of apoptotic, apoptotic necrotic and necrotic percentages, as well as significant decrease of deltaPsim were observed at higher light intensity in part one study. Increase of apoptotic percentage was the main response to shorter exposure of blue light. Increase of apoptotic necrotic and necrotic percentage and pronounced decrease of deltaPsim occurred in cells irradiated by longer exposure in part two study. In part 3 study, apoptotic response was increased gradually during 6 and 12 hours prolongation of post-exposure culture, more apoptotic necrosis or necrosis were found after post-exposure 24 hours. Decrease of deltaPsim was observed in 6 hours prolongation of post-exposure culture and lasting for 48 hours. The concentration of cytochrome C was significantly increased in post-exposure 24 and 36 hours, without any changes of Caspase-3 activity. Blue light exposure can induce damages to human RPE cells in vitro, which include apoptosis, apoptotic necrosis and necrosis. These changes are caused by triggering the mitochondrial permeability transition, which results in decrease of deltaPsim and release of cytochrome C. deltaPsim can be used as a earlier parameter of blue light-induced apoptosis.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 01/2007; 42(12):1095-102.
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    ABSTRACT: To investigate the effect of endostatin on the pathogenesis and development of retinal neovascula animal model of oxygen-induced retinopathy. The animal model of oxygen-induced retinopathy was made by subjecting postnatal mice to hyperoxic conditions (5 days) followed by normoxic conditions. Retinal angiogram was taken by using high molecular weight fluorescein-dextran. The degree of hyperoxia-induced neovascularization in serial paraffin cross-sections was quantified by counting the number of vascular cell nuclei on vitreal side of the internal limiting membrane. The expression of ES and VEGF in the oxygen-induced retina was observed by immunohistochemistry. We successfully constructed the oxygen-induced retinopathy mouse model. FITC-dextran retinal angiography indicated that hyperoxia could produce constriction of retinal vasculature and vaso-obliteration or irreversible closure of many capillary channels and eventually result in non-perfused area in the post-area of retina surrounding the optic disk. Relatively, hypoxia could lead to dilation and torsion of retinal vessels. There were averagely 22 neovascular nuclei per cross-section of eyes in the hyperoxia group and less than 3 nuclei per cross-section of eyes in the control group (P < 0.05). The expressions of ES and VEGF in the retina under hyperoxia were stronger than those under normoxia, expecially the expression of VEGF. Taking measures to up-regulate the expression of endogenetic endostatin may have the potential for effective treatment of retinal ischemic neovascularization.
    Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 07/2006; 37(4):614-7.
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    ABSTRACT: To answer the question whether mitochondrial permeability transition (MPT) participates in blue light-induced damage to human retinal pigment epithelium (RPE) cells, this study was directed at assessing the effect of blue light on mitochondrial membrane potential (delta psi(m)) and cytochrome C (Cyt C) of cultured human RPE cells. Human RPE cells were exposed to blue light (wave length 470-490 nm); delta psi(m) was measured by rhodamine 123 staining and subsequent flow cytometry. Three groups were investigated: Group A (exposure to different intensity of blue light); group B (exposure to identical intensity for different duration); group C (exposure to identical intensity and duration, different prolongation of post-exposure culture). Cyt C activity was assayed by ELISA. Caspase-3 was detected by colorimetric assay. In these aspects, two groups were investigated: Group I [(2000+/-500) 1x for 6 h]; Group II [(2000+/-500) 1x for 12 h]. When human RPE cells were exposed to blue light, the more pronounced decrease of delta psi(m) was consistent with the increase of light intensity in group A. Pronounced decrease of delta psi(m) was seen at 6 h and 12 h of exposure duration in group B. At 6 h prolongation of post-exposure culture in group C, the decrease of delta psi(m) was observed, lasting 48 h. The concentration of Cyt C was detected; no significant changes were found at 6 h and 12 h prolongation of post-exposure culture, but a significant increase was found at 24 h and 36 h post-exposure in the two groups. The increase was more significant in Group II than in Group I at 24 h post-exposure. The activity change of caspase-3 was not found in the two groups. Blue light exposure over threshold can induce damage to human RPE cells, probably by triggering the mitochondrial permeability transition, which results in the decrease of delta psi(m) and the release of cytochrome C.
    Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 02/2005; 36(1):57-9, 96.
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    ABSTRACT: To assess the expression of bFGF, FGFR1, Bcl-2 and caspase-3 in human RPE cells exposed to visible light in vitro. Cultured human RPE cells were exposed to visible light [(2,000 +/- 500) Lux] for 12 hours. Immunocytochemical staining, enzyme-linked assays and RT-PCR were used to determine the expression of bFGF and its receptor FGFR1, Bcl-2 as well as the activity of caspase-3. (1) Bcl-2 was detected in normal cultured human RPE cells. No significant change was found at 6 or 12 hours after light exposure (P > 0.05). But 24 hours after exposure, a significantly decreasing of Bcl-2 expression was observed (P < 0.01). The changes in expression of Bcl-2 mRNA paralleled to the changes in its protein, except that differences could be detected earlier viz. 12 hours after exposure. (2) The upregulation of bFGF and FGFR1 mRNA expression occurred with longer period of light exposure (P < 0.05). (3) The upregulation of caspase-3 activity was detected 6 hours after light exposure, and was more significant over 6 hours and 12 hours (P < 0.05). No significant difference was found between 12 hours and 24 hours exposure (P > 0.05). Visible light exposure over threshold causes upregulation of endogenous bFGF and FGFR1, downregulation of Bcl-2 and activation of caspase-3 in human RPE cells.
    [Zhonghua yan ke za zhi] Chinese journal of ophthalmology 12/2003; 39(11):655-9.