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O O Pedersen

Publications and source records attributed to O O Pedersen.

29 records · Page 2Linked to original sources
PubMed1978

The ciliary body and the iris in experimental uveitis in rabbits. A scanning electron microscopic study.

Acute anterior immunogenic uveitis of varying degree was induced in rabbits by the injection of human serum albumin into the vitreous body. After fixation and drying by the critical point method, the lens, the zonules, the vitreous and, in some specimens, coagulated exudate were removed by careful dissection. The surface of the ciliary body and the posterior surface of the iris were examined by scanning electron microscopy. In moderate uveitis, the ciliary body was covered by a thin layer of leucocytes enmeshed in fibrin strands. Scattered deposits of fibrin and a few leucocytes were also found in the iris. In severe uveitis, the processes of the ciliary body had nearly disappeared because of oedema and exudate, which also contained erythrocytes. The numerous leucocytes had marked excrescences formed by folds of the cell membrane. Fibrin seemed to play a role in the attachment of the leucocytes on the surface of the ciliary body.

Acute Disease↗
PubMed1977

The permeability of the human ciliary and iridial epithelium to horseradish peroxidase. An in vitro study.

The permeability of the human ciliary epithelium to horseradish peroxidase (PO) has been studied in vitro with the electron microscope. Ciliary body and iris specimens were obtained from freshly enucleated eyes. PO was applied at the stromal side of the epithelium, and was left for 120 min. The movement of PO through the intercellular spaces of the human ciliary epithelium was blocked apically in the lateral intercellular spaces of the non-pigmented epithelial cells, indicating that these cells are girdled by zonulae occludentes. In the iridial epithelium, the same distribution pattern of peroxidase reaction products (PORP) was found, i.e. the progression of PO was blocked apically in the lateral intercellular spaces of the posterior epithelial cells. The study indicates that the human ciliary and iridial epithelium contains a system of zonulae occludentes, which represents a diffusion barrier to high molecular, water soluble substances. This is consistent with previous studies in several species of animals.

Adult↗
PubMed1975

In vitro studies on peroxidase movement in the epithelium of prostaglandin-treated rabbit ciliary bodies.

The movement of horseradish peroxidase (HRP) in the epithelium of isolated rabbit iris/ciliary body preparations, has been studied with the electron microscope. HRP was applied at the stromal side of the epithelium, and was left for 60 and 120 min. The distribution pattern of HRP found in the epithelium of the iridial and ciliary processes is consistent with in vivo studies, i.e. the progression of HRP is blocked at the site of the zonula occludens of the superficial epithelium. The HRP distribution pattern found in the iris epithelium indicates that also the superficial epithelial cells of this epithelium are girdled by zonulae occludentes. Specimens treated with prostaglandins E1, E2, and F2alpha, showed no change in the epithelial distribution pattern of HRP, and the occluding zonules were found to be intact.

Animals↗
PubMed1975

Electron microscopic studies on the blood-aqueous barrier of prostaglandin-treated rabbit eyes. I. Iridial and ciliary processes.

Prostaglandins E1 and E2 were applied topically to rabbit eyes. Structures related to the blood-aqueous barrier in the iridial and ciliary processes, as well as the permeability of the ciliary epithelium to the protein tracer horseradish peroxidase, were studied with the electron microscope. Marked morphological changes, including dilations of the intercellular spaces and separation of the two epithelial cell layers, were found in the epithelium of the iridial processes. Only minor structural changes were found in the epithelium of the ciliary processes. Leakage of peroxidase through the intercellular spaces of the epithelium was demonstrated in the iridial processes and in the anterior parts of the ciliary processes. In the ciliary vessels of the same regions, opening of interendothelial gaps, platelet aggregations, microthrombi, and haemorrhages were found. In a previous in vitro study on the effects of prostaglandins on the movement of peroxidase in the ciliary epithelium, no structural changes of the epithelium were found, and the epithelial diffusion barrier to peroxidase was found to be intact. It is assumed that the breakdown of this barrier in vivo is secondary to vascular changes.

Animals↗
PubMed1975

Electron microscopic studies on the blood-aqueous barrier of prostaglandin-treated rabbit eyes. II. Iris.

The distribution of intravenously injected horseradish peroxidase in the iris of prostaglandin (E1 and E2)-treated rabbit eyes, has been studied with the electron microscope. Peroxidase was demonstrated in the stroma of all parts of the iris. The tracer was found throughout interendothelial clefts of iris vessels, indicating that these vessels had become permeable to peroxidase. The distribution of peroxidase in the iris epithelium indicates that the posteroir epithelial cells are girdled by zonulae occludentes.

Animals↗