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Biomedical subjects

K R Kenyon

Publications and source records attributed to K R Kenyon.

At least 217 records · Page 12Linked to original sources
PubMed1975

Fibroglial proliferation in pars planitis.

In a 51-year-old patient with long-standing pars planitis, light and electron microscopical examination of the intravitreal 'snowbank' revealed a fibrovascular layer adjacent to the hyperplastic nonpigmented epithelium of the pars plana and an extensive fibroglial proliferation within the vitreous base. The fibrovascular layer consisted of well-differentiated capillaries, probably emanating from the peripheral retina, interspersed with aggregated vitreous fibrils. The fibroglial portion of the 'snowbank' was composed of fibrous astrocyte-like cells which had secreted basement membranes and larger diameter collagen fibrils. This fibroglial tissue was in direct continuity with an ultrastructurally similar preretinal membrane. No significant choroiditis or cyclitis could be demonstrated. It is hypothesized that, in pars planitis, a primary inflammatory process of the peripheral retina and vitreous base may stimulate the observed preretinal and intravitreal fibroglial proliferation.

Ciliary Body↗
PubMed1974

Effects of cyclic AMP and Sephadex fractions of chick embryo extract on cloned retinal pigmented epithelium in tissue culture.

The effects of dibutyryl cyclic 3',5'-adenosine monophosphate (BcAMP) and Sephadex G-25 fractions of chick embryo extract on the growth rate, morphology, and pigmentation of normal chick retinal pigmented epithelium (PE) were investigated. Seven cloned PE cell lines were each grown in modified Ham's F-12 medium alone (F-12), or in F-12 supplemented with either high molecular weight (H) or low molecular weight (L) fractions of chick embryo extract. Cells grown in F-12 alone or in L medium formed compact epithelial sheets, whereas cells grown in H had a fibrocytic appearance and formed poorly organized monolayers. In H plus BcAMP, cell morphology was more epithelioid than in H alone, and generally the monolayers appeared more differentiated. Under each of these three culture conditions, 2 x 10(-4) M BCAMP retarded the increase in cell number and decreased the final number of cells per culture dish, but had little effect on plating efficiency. BcAMP also increased the rate of cell adhesion to a plastic substratum. Pigmentation was marked in cultures grown in F-12 or in L alone, but the addition of BcAMP dramatically reduced visible pigmentation. This effect was reversed when BcAMP was removed from the culture medium. Thus BcAMP modifies cell and colonial morphology, rate of cell accumulation, adhesive properties, and pigmentation of normal PE cells.

Animals↗