Biomedical subjects

R Machemer

Publications and source records attributed to R Machemer.

At least 181 records · Page 10Linked to original sources

PubMed1975

Clinical-pathological correlation in massive periretinal proliferation.

In the owl monkey, proliferation of pigment epithelial and glial cells occurred in varying degrees in nearly all eyes with retinal detachments. These cells grew and formed membranes on all available intraocular structures in the posterior part of the eye, such as vitreous structures and inner and outer retinal surfaces. Clinically, this process covered a wide variety of lesions, including fixed retinal folds. Depending on the location, size, and extent of the pigment epithelial or glial membrane, different types of fixed folds occurred. In an exaggerated end stage of this proliferative process, a clinical picture may develop identical to what has been called massive vitreous retraction or massive preretinal retraction in humans. To emphasize the importance and ubiquity of cellular proliferations, we called this entity massive periretinal proliferation.

Animals↗

PubMed1975

Glial cell proliferation in retinal detachment (massive periretinal proliferation).

In experimental retinal detachment of the owl monkey we observed the formation of preretinal and subretinal membranes which had cellular connections to the retina proper. Based on light microscopic findings we concluded that retinal cells grow out of the retina and build up the preretinal and subretinal tissue. Electron microscopically these cells are identified as astrocytes which grow out through focal interruptions in the internal or external limiting membrane. In the immediate area of outgrowth Muller cell processes praticipate in the formation of the preretinal or subretinal tissue. These glial membranes can cause wrinkling of the internal limiting membrane and the nerve fiber layer or full-thickness folding of the retina. Glial proliferation plays an important role in the development of a complication in retinal detachment which we suggest calling "massive periretinal proliferation" (MPP).

Animals↗

PubMed1975

Sulfur hexafluoride in owl monkey vitreous cavity.

Sulfur hexafluoride (SF6) gas, tested in the vitreous chamber of owl monkey eyes, remained in the vitreous cavity about twice as long as air (ten to 11 days vs. five to six days). Its volume expanded from the diffusion of other gases into the created gas pocket. Lens opacities developed when the lens was in continuous contact with SF6 or air. Sulfur hexafluoride appeared to be no more toxic to the retina than air, using electroretinographic, histologic, and electron microscopic criteria.

Air↗

PubMed1975

Pigment epithelium proliferation in retinal detachment (massive periretinal proliferation).

Cell proliferation and membrane formation found in the posterior parts of the eye after production of retinal detachment in owl monkey eyes had either the characteristics of macrophages or of membrane-forming epithelial cells. The proliferating cells originated from pigment epithelium. These membranes caused folding of the retina and strand formation in the vitreous cavity. Since cell proliferation was present on all available surfaces, such as the upper and under surface of the retina, and along vitreous surfaces, we propose to call this entity "massive periretinal proliferation" (MPP).

Animals↗

PubMed1975