The retinal pigment epithelium and photoreceptor cells light-and electron microscopic studies on monkey eyes

Bülow, Niels

doi:10.1007/bf00224142

Cited by 8 publications

(3 citation statements)

References 33 publications

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“…However, the present results indicate, that as the disintegration of the damaged tissue was completed by the phagocytic cells, they accumulated small granularlamellar inclusions, melanosomes in different stages of melanization, melanin granules and compound inclusions. As the accumulation of these categories of inclusions may indicate melanogenesis in the adult (Bulow 1975), the present results suggest that melanogenesis was initiated in the phagocytic cells as the disintegration of the damaged tissue was completed. The evidence of melanogenesis may be regarded as a further step in the differentiation of the phagocytic cells, supporting the consideration that they originate from the pigment epithelium.…”

Section: The Process Of Wound Healing Of the Retinal Lesionsmentioning

confidence: 51%

“…In the monkey, Cercofiilhecus aelhioii., (Briinnich), a series of 20 perifoveal Laser lesions were produced, four in each eye. In three animals the lesions were produced in the right eye at time intervals of eight hours, whereas the left eyes were used as normal material (Bulow 1975). In a fourth animal the lesions were produced in both eyes at different time intervals.…”

Section: Methodsmentioning

confidence: 99%

“…As an approach to the investigation of these processes morphological studies have been made on the normal retina and on a series of retinal Laser lesions of the monkey, CercopitheLris uethiop.c. In the normal retina the relations between the photoreceptors and the pigment epithelium and the different types of inclusions in the pigment epithelial cells have been described and discussed (Bulow 1975). The present paper provides a survey of the studies on Laser lesions with special emphasis on the process of wound healing.…”

Section: Introductionmentioning

confidence: 97%

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The Process of Wound Healing of the Avascular Outer Layers of the Retina

Bülow

1978

Acta Ophthalmologica

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The process of wound healing of the avascular outer layers of the retina is studied on a series of Laser lcsions of the monkey, Ccrc.oliitl/fr.ilt;~~~~.~ uelhio/).s. T h e extent of the retinal lesions is limited to thc pigment epithelium and photoreceptor cells, whereas Bruch's membrane anti the vascular inner layers of the retina remain intact. The retinal lesions arc not seen to be invaded by cells from the chortiid. nor from the retinal vessels. During the first three days after irradiation the pigment epithelial cells in a zone, about 7 5 pin wide. around the lesions appear to be changcd into bi-or multinucleate cells with thc additional nuclei situated in apical cytoplasmic protrusions which extend towards and into the lesions. During the second and third days after irradiation the lesions arc invaded by two kinds of cells which both appear to arise through the off-budding of the nucleus-containing apical protrusions of the pigment epithelial cells around the lesions: (a) phagocytic cells which disintegrate the damaged tissue and, as this process is completed 4-9 days after irradiation show cvitlence of melanogcncsis; and (b) regenerated pigment epithelium which forin a single lnycr of rells along Bruch's membrane, but show no evidc nce of phagocytosis or intracellular disintegration of the damaged tissue. Within the lesions both these kinds of cells show mitotic figures the third clay after irratliation.

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Section: The Process Of Wound Healing Of the Retinal Lesionsmentioning

confidence: 51%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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The Process of Wound Healing of the Avascular Outer Layers of the Retina

Bülow

1978

Acta Ophthalmologica

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Origin and organization of pigment epithelial apical projections to cones in cat retina

Fisher

Steinberg

1982

J of Comparative Neurology

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The apical surface of the retinal pigment epithelial cells (RPE) in the cat extend long sheetlike membranes that wrap concentrically above and around cone outer segments forming the cone sheath. The origin and organization of these sheetlike projections were studied in serial sections by electron microscopy. The apical surface of the RPE cells was found to consist of a thin zone of anastomosing ridges, or microplicae, from which longer projections extend. The lamellar projections forming the cone sheath originate from the microplicae as small cytoplasmic tabs that rapidly expand into broader sheets. Growth of individual sheets to their final size and shape continues by lateral and longitudinal expansion, fusion, and subdivision of the membrane. The small area of connection to the cell body allows the lamellae to overlap and interdigitate in forming the complex organization of the sheath. Microfilaments but not microtubules extend into the apical processes. RPE cilia (9 + 0 microtubules) with associated basal bodies, striated rootlets, and microtubules mark the location of retinal cones. These structures may be part of a microtubule organizing center that participates in morphogenesis of the cone sheath. They also may be involved in anchoring the apical projections forming the sheath, or in the movement of apical projections during the phagocytosis of outer segment discs shed from cone tips.

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Retinal pigment epithelial correlates of avian retinal degeneration: Electron microscopic analysis

Fite

Bengston

Doran

1985

J of Comparative Neurology

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The delayed amelanotic (DAM) strain of domestic chicken is characterized by an early, developmental onset of choroidal inflammation and destruction of both feather and choroidal melanocytes. Secondarily, retinal pigment epithelial (RPE) cells in the peripapillary region develop abnormalities, and a series of progressive histopathological changes ensues which includes reduction and ultimate loss of RPE-melanin granules and RPE-cell atrophy. The earliest sign of RPE-cell abnormality is a dramatic alteration in the distribution of intracellular melanin granules. Apical processes also show a lessening of contact with photoreceptor outer segments, leading in more advanced stages to their retraction and development of retinal detachments. Other progressive alterations in RPE cells include disorganization and loss of basal infoldings; size reductions and density increases in both mitochondria and myeloid bodies from early to advanced stages; appearance of large macrophages in the subretinal space; Loss of intercellular junctional complexes; and progressive reduction in the density of melanin granules. These abnormalities appear to spread in a cell-by-cell, radial pattern, until widespread areas of the retina become severely pathologic and atrophic. The DAM chorioretinal disorder appears to show many of the histopathologic features which characterize experimentally induced uveitis and other ocular diseases which may result from hypersensitivity to, or autoimmune reaction against, pigments of the uveal tract.

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The retinal pigment epithelium and photoreceptor cells light-and electron microscopic studies on monkey eyes

Cited by 8 publications

References 33 publications

The Process of Wound Healing of the Avascular Outer Layers of the Retina

The Process of Wound Healing of the Avascular Outer Layers of the Retina

Origin and organization of pigment epithelial apical projections to cones in cat retina

Retinal pigment epithelial correlates of avian retinal degeneration: Electron microscopic analysis

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