Retinal histopathology of a carrier of X-chromosome-linked retinitis pigmentosa.

Autopsy eyes were examined from a 79-year-old female carrier of X-chromosome-linked retinitis pigmentosa. At age 78 years, she had no visual symptoms but had intraretinal bone spicule pigmentation in the nasal and inferior periphery of both eyes. Rods, cones, and pigment epithelium in the central retina appeared normal.

The visual cells of the skate retina: structure, histochemistry, and disc-shedding properties.

Earlier studies have shown that visual function in skate is subserved solely by the rod mechanism and that the retina of this elasmobranch contains only rod photoreceptors. Nevertheless, the skate retina is capable of responding to levels of illumination that extend well into the photopic range, and we have detected in histological sections (usually from younger animals) small, proximally displaced, conelike photoreceptors which possibly represent another class of visual cell. However, ultrastructural and histochemical studies showed that the membranous discs of the outer segments of these cells were isolated from the plasma membrane, and that their synaptic terminals appeared immature and unlike those usually associated with cone receptors.

Scanning electron microscopy of rabbit corneal scars.

Central full-thickness perforating excision wounds were made in rabbit corneas and were examined by light and scanning electron microscopy at various times after wounding to study the three-dimensional morphologic changes in the tissue during healing and remodeling. Formation of a fibrin clot soon after wounding seals the hole and functions as a substrate for the healing epithelium. Changes in the histologic appearance of the fibrin lot immediately below the new epithelium are followed by migration of adjacent stromal cells under the epithelium, parallel to the basal surface of this tissue.

Histopathologic study of an unusual form of retinitis pigmentosa.

An ultrastructural study was done on a postmortem donor eye from an 84-year-old male with night blindness, pericentral ring scotomas, attenuated retinal arterioles, and intraretinal bone spicule pigmentation distributed around the midperiphery. Unusual findings observed 3 years prior to death were preserved central vision and peripheral visual field and rod and cone electroretinogram amplitudes reduced only about 60% below normal. Ultrastructural examination of the retina revealed apparently normal numbers of cones in the fovea, reduced numbers of rods on the foveal slope, absence of photoreceptors in the midperiphery, and large areas of preserved rods and cones in the far periphery in all quadrants.

Selective phagocytosis of liposomes by cultured RCS rat pigment epithelium.

Liposomes 0.5 to 5 micron in diameter and of various phospholipid compositions were used as a simplified model of rod outer segment membranes to examine the phagocytic mechanism of cultured explants of retinal dystrophic Royal College of Surgeons (RCS) and normal Long-Evans (LE) rat pigment epithelium. RCS pigment epithelium explants phagocytized liposomes composed of phosphatidylserine (pS) plus phosphatidylinositol (pI).