To observe the morphological changes in photoreceptor after experimental retinal detachment in cats. Twenty eight cats were divided into experimental group and control group. Retinal detachment was produced by injecting 0 25% solution of Healon into the subretinal space with the aid of a micropipette. Histologic sections of retina were processed for light and electron microscopy at detachment intervals ranging from 0 5 days to 3 months. At 24 hours postdetachment, the outer segments were distended and disrupted, but the inner segments and photoreceptor cell bodies were only slightly affected. 3-14 days after detachment, the inner segments were affected at multiple sites, albeit to varying degrees. Some of them were vacuolizated at the tip, with mitochondria swollen and cristae fragmented. At the same time, the photoreceptor cell bodies often showed a distension of endoplasmic reticulum, deterioration of mitochondria, and the presence of multivesicular bodies. 1-3 months after detachment, large empty spaces in the outer nuclear layer and a progressive loss of cytoplasmic ground substance and organelles appeared in some photoreceptors as detachment duration lengthened. Necrosis of the inner segments and cell bodies were more marked in the more serious detachment than those in shallow ones. Degenerative changes occured in the photoreceptor very soon after experimental retinal detachment, and these changes were correlated with both the depth and duration of retinal detachment.

Objective To investigate the rule of the talar growth and establish a normal radiographic measurement scale of the talus from postnatal infants to adults. Methods Radiographic measurements were performed with the lateral radiographs of right talus in 1*!765 normal cases(age 1 to 18). Results The talar growth velocity was the fastest before two years old.It was consistent with the development of physiques(e.g.height and weight),and then there was not a remarkable increase in the talar growth.At puberty,a temporal sudden increase was not found in the talus.Conclusion Radiographic measurements not only provide a normal contrast for the flats of the talus or the abnormal shapes caused by some congenital or acquired disease,but also was useful to the other subject(e.g.anthropology,forensic science).