Laser induced phagocytosis in the pigment epithelium of the Hunter dystrophic rat

The retinae of 14-day-old Hunter dystrophic rats have been subjected to low-energy irradiation by a pulsed ruby laser. Fifteen days after exposure, pigment epithelial cells had proliferated and repopulated the irradiated areas. In all such areas the subretinal photoreceptor debris had been reduced or lost.

Choline acetyltransferase in ocular tissues of rabbits, cats, cattle, and man

The variation of choline acetyltransferase activity in ocular tissues of four mammalian species, rabbits, cats, cattle, and man, was determined. Enzyme activity of irides and ciliary bodies, i.e., parasympathetically innervated structures, tended to be similar in all four species. Two exceptions were bovine irides and human ciliary bodies; these two tissues had higher enzyme activities. Choline acetyltransferase activity was present in the corneal epithelium of rabbit, bovine, and human eyes, but little or none could be detected in that of cats. Feline retina and pigment epithelium-choroid also contained far less choline acetyltransferase activity than the same tissues in the other three species.

Primary retinal degeneration: evidence of normal phagocytosis in the retinal pigment epithelium

In rats with primary retinal degeneration, lens extraction combined with total retinal detachment provided a model for injection of a tracer of colloidal carbon into the subretinal space. Electron microscopy and acid phosphatase cytochemistry were subsequently used to analyze the ingestion of tracer by the retinal pigment epithelium. It was found that the attachment, ingestion, and digestion phases of the phagocytic process were apparently preserved. From this evidence it is suggested that there is no lack of phagocytic power in the retinal pigment epithelium of affected rat strains.

[Myeloid bodies of the retinal pigment epithelium in vertebrates]

After the hypothesis of Porter and Yamada about the photoreceptive role of myeloid bodies of the vertebrate pigment epithelium, we have pointed out the fine ultrastructure of these organelles: they consist of piles of flattened saccules, with a lipidic content, and linked together by an inter-saccular cement. They are not like Golgi bodies: they do not content glycoprotein. They must be discarded from phagosomes, which are membrane-bounded and content acid phosphatase activity. An oxido-reductive activity cannot been demonstrated at their level, similar to that observed on the rod outer segments. Freeze-etching does not show peculair organization on their fracture faces. They represent a special organization of the endoplasmic reticulum which seems to have a function in the metabolism of visual pigments in certain species of animals, the retina of which is avascular.