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Objective To examine the expression of proliferating cell nuclear antigen (PCNA) of retinal pigment epithelial (RPE) cells, thus assessing the role of mechanism of contact inhibition playing in the process of experimental retinal detachment and reattachemnt. Methods Retinal detachment was produced in 72 cats by subretinal injection of 0.25% solution of healon through a micropipette three weeks after extracapsular lens extraction and vitrectomy. Some of the detached retinae were reattached 24 hours later. At different time, the cats were killed and eye globes were fixed and embeded in paraffin. Histologic sections were processed for immunohistochemistry examination using an antibody to detect PCNA protein. Labeled RPE cells were identified, and the proliferation was quantified in detached and un detached retinae of detachment group, and also in reattached retinae of reattachment group. The comparsion of PCNA labeled RPE cells in different groups were analyzed by ANOVA. Results In detached regions of detachment group, PCNA expression of RPE cells occured within 24 hours, and reached a maximum after 5 6 days, then gradually declined to barely detectable levels after 20 days. Similar tendency was found in reattached retinae, but the number of PCNA labeled RPE cells was obviously small. Fewer PCNA labeled RPE cells were found in regions of un detached retinae in detachment group. The difference of these three groups was significant. Conclusion Proliferation of RPE cells is induced when they lose contact with neural retina, but inhibited after neural retina reattached to RPE cells. It suggests that the mechanism of contact inhibition plays a role in the proliferative process after retinal detachment and reattachment.

6.Clinicopathological features of IgA nephropathy associated with malignant hypertension and their correlation to renal vascular lesions

Pu CHEN ; Xiangmei CHEN ; Yuansheng XIE ; Guangyan CAI ; Xuefeng SUN ; Suozhu SHI ; Jie WU ; Zhong YIN

Chinese Journal of Nephrology 2008;24(6):392-397

Objective To explore the clinicopathological features of IgA nephrolpathy associated with malignant hypertension (IgAN-MHT) and to analyze their correlation with renal vascular lesions. Methods Twenty-nine patients of IgAN-MHT were screened from 2000 biopsy-proven eases with primary IgA nephropathy (IgAN) in our department from April 1997 to May 2007. Data of clinicopathology and follow-up of these 29 patients were collected. Semi- quantitative analysis was performed to evaluate the pathological changes. Inner lumen, outer lumen, intimal thickness, tunica media-to-internal lumen ratio of 436 arterioles, 124 interlobular arteries and 5 arcuate arteries were measured. The primary endpeint was the composite of a doubling of serum creatinine level and ESRD. Correlations of renal vascular lesions with clinical manifestation, pathological change and prognosis were examined by Spearman and Cox methods. Results 1.5% of all the IgAN patients presented malignant hypertension. The common clinical features were renal failure (100%), hyperurieacidemia (62.7%) and hypertriglyceridemia (51.7%). The average amount of urine protein excretion was 2.8 g/d. The common pathological changes were moderate mesangial proliferation, severe global sclerosis, severe interstitial inflammation and severe interstitial- tubular fibrosis. The small arteries (arcuate arteries and interlobular arteries) and arterioles (afferent arterioles) were both involved in IgAN-MHT. The characteristic lesions of intrarenal arteries included vascular occlusion, media thickening, proliferative endarteritis (onionskin lesion, musculomucoid intimal hyperplasia), hyaline arteriosclerosis, but mainly vascular occlusion (86.2%). The arteriole lesion was negatively correlated with age and total protein level; vascular occlusion was positively correlated with uric acid level. The average foUow-up period was 21.1 months. Forteen patients reached the endpoint. The arteriole lesion was the main independent risk factor for the progression of IgAN-MHT (RR=10.21, 95%CI=1.16～89.67). Conclusions The main clinical feature of IgAN-MHT is renal failure. The main histological feature of intrarenal vascular lesions is occludes arterioles. Arteriole lesion is the main independent risk factor for the progression of IgAN-MHT.