Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
The Chinese human hepatocellular carcinoma cell SMMC7721 has been analysed by flow cytometry, Southern blotting and Western blotting. The results indicated that SMMC7721 cell is a hypoploid cell with a 0.81 DNA index, and that SMMC7721 cell has internal deletion in the 5'-end of its Rb gene and has no Rb gene product (Rb protein). The normal Rb cDNA has been inserted into a retrovirus vector DOL and introduced into SMMC7721 cells by electrporation transfection technique.About 75% of transfected SMMC7721 cells have been killed by Rb gene product. The remain 25% cells are alive as exogenous Rb gene has been mutationally inactivated. （Chin J Ocul Fundus Dis,1994,10:21-24）
Objective To investigate inhibited effects of melatonin (MLT) on proliferative activity of retinoblastoma cell line HXORB44 and its related mechanism. Methods HXO-RB44 cells were treated by MLT of different concentration (10-10, 10-9, 10-8, 10-7 mmol/L. Cell counting and tetrazolium dyereduction assay (MTT) were used to determine the effect of MLT on the survival and proliferation of HXO-RB44 cells. Apoptotic nuclei were further analyzed by HoechstPI fluorescence staining. Flow cytometry was used to measure the fluorescent intensity of ROS, cell cycle distribution and apoptosis. Results 10 -6 mmol/L (or exceed) of MLT could inhibit the proliferation of HXO-RB44cells in vitro while 10-7 mmol/L (or below) of MLT couldn't. With the increase of MLT concentration from 10-10 mmol/L to 10-7 mmol/L, HXO-RB44 cells gradually increased the expression of ROS. Hoechst staining showed that 4, 8, 12 and 24 hours after the incubation with MLT, the nuclear pyknosis and nuclear fragmentation increased in HXORB44 cells. The extent of apoptosis was proportional to the concentrations of MLT. Flow cytometry revealed that with the increasing of MLT concentration, G0/G1 and G2/M phase cells increased, S phase cells decreased. The apoptotic rate was also increased. Conclusion 10 -6 M of MLT could inhibit the proliferation of HXO-RB44 cells. This effect may relate to the increased ROS expression, cell cycle arrest at G0/G1 phase and apoptosis of HXO-RB44 cells.
A review of 426 patients with retinoblastoma(RB)who presented to Eye Hospital of Zhongshan Ophthalmic Center from 1966 to 1991 showed that 81(19.01%)patients were more than or equal to 5 years of age(median age 6.95 years)at the time of initial diagnosis.All patients are unilateral except 4 cases who are bilateral.The main presentations included leukocoria,exophthalmos,congertion and pain of the eye,drcreased vision,strabismus,oculare hypertension,vitreous opacity,hypopyon and hyphema,etc.Some atypical presentations in these older patients with RB were discussed and some problems that should be noticed in the diagnosis and management were presented.discussed and some problems that should be noticed in the diagnosis and management were presented. （Chin J Ocul Fundus Dis,1993,9:205-206）
Objective To investigate the effect of exogenous Rb gene on the cell cycle of vitreous retinoblastoma (RB) transplantation tumor in nude mouse. Methods Based on establishing vitreous RB transplantation tumor in nude mouse,constructing retrovirus vector of Rb gene PBabe-Rb and transfecing it into the RB transplantation model by liposome Dosper,the change of cell cycle of the RB transplantation tumor by flow cytometry(FCM)was analysed． Results FCM showed that the cells of G1phase of the treated eyes were obviously more than the control eyes with the value of DNA index(DI)and S phase fraction(SPF) decreased by the Rb gene expression. Conclusion The exogenous PBabe-Rb gene can partially suppress the progress of the cell cycle of RB transplantation tumor in vivo. (Chin J Ocul Fundus Dis，2000，16：1-70)
PURPOSE:To investigate the relationship between the proliferative activity of refinoblastoma (RB)cell and the RB differentiation degree and the infiltration capability. METHOD:The proliferating cell nuclear antigen (PCNA)expression in RB tissues of 48 cases was analysed by using LSAB immunohistochemical method. RESULTS :The mean PCNA labelling index(LI)in differentiated RB tissues of 12 cases was markedly lower than that in non-differentiated of 36 cases(P＜0.05). The mean PCNA LI in RB tissues of the optic nerve infiltrated group(22 cases)was significantly higher than that of the optic nerve non-infiltrated group(26 cases)(P＜0.05). The results indicate that the PCNA LI is significantly related with the differentiation degree of RB and the infiltration capability. CONCLUSION :The determination of PCNA LI is of significance for evaluating the histologic characteristics and biological behavior of RB.
OBJECTIVE:The hereditary form of retinoblastoma(RB)is a monogenic disorder which is due to germinal mutation of RB susceptibility gene located on 13q14.The majority of hereditary RB cases transmit as a Mendelian autosomal dominant inheritance that 50% of the offspring of a carrier will inherit the disorder susceptibility gene and all carriers will develop the disorder.The authors report 3 hereditary RB families with incompleted penetrance and irregular transmission of RB phenotype. METHOD:RFLPsamp;VNTRs for analysis of haplotype and SSCPamp;direct DNA sequencing for determination of RB point mutation. RESULTS:The mosaicism of Rb gene point mutation resulted in the incompleted penetrance and irregular transmission of RB phentype. CONCLUSION:DAN-based diagnosis can be used to differentiate the hereditary and nonhereditary forms of retinblastoma but only is the direct detection of disease-causing mutation reliable for determnation of carrier and estimation of th e risk for retinoblastoma. （Chin J Ocul Fundus Dis,1996,12: 37- 40）