Ultrastructure of Rapidly Proliferating Preretinal Membrane of Very Extensive Ischemic Diabetic Retinopathy

PURPOSE: Using transmission electron microscopy (TEM), we studied the ultrastructures of rapidly proliferating preretinal membranes of young patients with very extensive ischemic proliferative diabetic retinopathy and diabetes with uncontrollable blood sugar level. METHODS: Nine cases of preretinal membranes were obtained from six eyes of five patients with rapidly progressed proliferative diabetic retinopathy (mean age, 35 years) during vitrectomy. We obtained each preretinal membrane bimanually as one single sheet membrane using intraocular scissors and forceps. Each tissue was fixed in 3% glutaraldehyde in the operating room. All specimens were prepared and studied using TEM. RESULTS: The preretinal membranes were composed of blood vessels and some interstitial cells. The blood vessels within the preretinal membranes varied in developmental stages, from the immature stage to the mature stage. The blood vessels were highly active, in that primitive cells showed a large nucleus and prominent chromatin clumping with abundant cytoplasm. Highly active fibroblast-like cells were also noted. CONCLUSIONS: We observed highly active angiogenesis in preretinal membranes, which rapidly proliferated in cases of severe retinal ischemia in young diabetes patients. This is the first report of such a finding, which may help to explain the poor prognosis of this disease modality.

Scanning Electron Microscopic Observations of Sequential Alterations of Type 1 HSV Keratitis in Rabbits

PURPOSE: This study aimed to investigate the microscopic findings of characteristic epithelial herpes simplex keratitis (HSK) and the changes of those findings over time. METHODS: Sixteen rabbits were inoculated with the Kos-stain of herpes simplex virus (HSV) type 1 in both eyes. Two rabbits each were enucleated on the 2nd, 3rd, 4th, 5th, 6th, 7th, and 9th day after viral inoculation and were observed with a scanning electron microscope (S-2380n, Hitachi, Japan). RESULTS: Corneas showed dendritic epithelial desquamation, changes in epithelial microvilli, and changes in intercellular adhesion. With progression, the basement membrane and basal cells were exposed, intercellular spaces were broadened, and the adhesion of basal cells to basement membrane and the intercellular adhesion were loosened. Later, infiltrations of some inflammatory cells were found. Until the last day there was no destruction of basement membrane or an exposure of stroma. CONCLUSIONS: Though it was impossible to follow up a lesion throughout the experiment because of the necessity of enucleation, and in addition, the findings could not be generalized to all the strains, this study provides a better understanding of HSK. Further studies on various manifestations of HSK from other strains of HSV are needed in the future.

The Morphologic Changes of Epikeratoplasty Lenticule In a Case

The patients initially underwent epikeratoplasty for keratoconus but a penetrating kerato plasty was required due to the opacity in the cornea. By using of this specimen, which was obtained by trephination the healing process of the host-Ienticule cornea could be examined by electron microscopy and immunofluorescence method. Epithelial ingrowth over the lenticule was well formed by the regeneration of the basement membrane over the Bowman's membrane. However, the poor attachment of the lenticule over the host corneal stroma made the interface easily separated during the sectioning processes. Electron microscopic study revealed the keratocytes in the lenticule stroma vacuolized with large number of degenerated microorganelles. These results suggest that it may take a long time to complete the wound healing of the host-Ienticule interface despite the epithelial ingrowth onto the lenticule was well formed.