PubMed Health⌕ Search

Biomedical subjects

S Okisaka

Publications and source records attributed to S Okisaka.

At least 91 records · Page 5Linked to original sources
PubMed1976

Effect of hyperosmotic agents on the ciliary epithelium and trabecular meshwork.

Hyperosmotic agents (2 M urea or 2 M DL-lactamide), perfused into the internal carotid artery of Rhesus monkeys, produced a marked decrease in intraocular pressure and an increase in aqueous humor protein. Fenestrae of the ciliary capillaries were broken immediately following the perfusion and the nonpigmented epithelium was separated from the pigmented epithelium. The pigmented epithelium especially of the pars plana then became degenerative. As intraocular pressure began to rise slowly, three to seven days after perfusion, the nonpigmented epithelium recovered to an almost normal structure, but the pigmented epithelium did not regenerate. The surviving cells in the pars plicata formed the original apico-apical junctions. The number of vacuoles in the endothelium of Schlemm's canal decreased while the intraocular pressure was low and increased gradually with the recovery of the intraocular pressure.

Amides↗
PubMed1976

Effects of paracentesis on the blood-aqueous barrier: a light and electron microscopic study on cynomolgus monkey.

The effects of paracentesis on the blood-aqueous barrier of cynomolgus monekeys were studied by light and electron microscopy. The following regions of the eye were examined: ciliary body, iris, Schlemm's canal, juxtacanalicular connective tissue, and trabecular meshwork. Prominent structural alterations were seen in the ciliary epithelium at the anterior portion of the pars plicata, but the epithelium at the posterior portion of the pars plicata and at the pars plana appeared less disrupted. Plasma proteins which crossed the capillary endothelium accumulated in the stroma, and appeared in the posterior chamber through the enlarged extracellular spaces of the ciliary epithelium. The plasma proteins in the ciliary stroma of the anterior portion of the pars plicata moved to the stroma of the iris root; whereas in the iris the capillary endothelium provide an impermeable barrier to proteins. Following paracentesis, the lumen of Schlemm's canal was invaded by blood, and through newly formed gaps in the endothelial lining of the inner wall of the canal, the plasma proteins and red blood cells rapidly diffused into the juxtacanalicular connective tissue, trabecular meshwork, and anterior chamber. On the basis of the present experiments, the protein of the aqueous humor can be considered as originating from both the anterior portion of the pars plicata and the inner wall of Schlemm's canal.

Animals↗
PubMed1975

The effects of laser photocoagulation in the retinal capillaries.

Using ruby and argon lasers, we produced multiple lesions on normal rhesus monkey retinas. The clinically used energy levels of both lasers produced identical cellular changes in the retina. Neither laser directly produced obliteration of capillaries. However, after the cellular damage in each burn lesion was repaired, we observed delayed degeneration of capillaries in a small segment at the burned areas. The marked reduction of active retinal cells that reduce vascular activity may beneficially affect laser treatment of diabetic retinopathy. The retinal tissue appears to have excessive photoreceptor cells and the horizontal connection of other cells seems to compensate for visual function after loss of many photoreceptor cells. We demonstrated severe damage in the ganglion cells by argon laser when it was aimed at the thick blood films in the vitreous cavity. Certain precautions must be taken when peripapillary neovascularization is treated by laser beam.

Animals↗
PubMed1974

Selective destruction of the pigmented epithelium in the ciliary body of the eye.

Perfusion of the internal carotid artery with hypertonic solution selectively destroys most of the pigmented epithelium of the ciliary body of the monkey eye, converts fenestrated endothelium of capillaries to continuous endothelium, and transiently breaks down the blood-aqueous barrier. The nonpigmented epithelium regenerates and the intraocular pressure returns to normal even though the pigmented epithelium is permanently destroyed.

Amides↗