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Biomedical subjects

A Kampik

Publications and source records attributed to A Kampik.

191 records · Page 11Linked to original sources
PubMed1981

Epiretinal and vitreous membranes. Comparative study of 56 cases.

Five morphologically distinguishable cell types were observed in 56 epiretinal and vitreous membranes obtained surgically from eyes with various ocular diseases: (1) retinal pigment epithelial (RPE) cells that were evident only in association with retinal detachment, (2)(macrophages, (3) fibrocytes, (4) fibrous astrocytes that were characteristic of all disease groups, and (5) myofibroblast-like cells that had mostly the characteristics of fibrocytes and, occasionally, of RPE cells or fibrous astrocytes. The combination of cell types varied in different types of epiretinal membranes, but the formation of collagen and the development of cells with myofibroblast-like properties were common features and seemed to be within the capacity of several cell types. These two common features seem to be the basis for the contractile properties of epiretinal and vitreous membranes.

Astrocytes↗
PubMed1981

Scanning and transmission electron microscopic studies of two cases of pigment dispersion syndrome.

We examined four eyes obtained post mortem from two patients who had increased intraocular pressure, normal visual fields, and pigment dispersion syndrome. Gross examination, light microscopy, scanning electron microscopy, and transmission electron microscopy disclosed elongated regions on the posterior iris surface of all the eyes. The cell membrane of the iris pigment epithelium was disrupted and there was extrusion of pigment granules at these locations. These areas of iris had a radial distribution (paralleling the course of the packets of zonular fibers) and corresponded to the peripheral iris transillumination defects. Pigment was dispersed in the anterior segment and on the pars plana. In the trabecular meshwork the pigment was free, within macrophages, and within endothelial cells. We observed giant vacuoles in the endothelium of Schlemm's canal. These findings suggested that friction between the zonular fibers and peripheral iris led to focal disruption of iris pigment epithelium and release of pigment granules. The increased pigment within the trabecular meshwork and Schlemm's canal may indicate that the glaucoma sometimes associated with pigment dispersion is caused by pigmentary obstruction, although congenital imperfections of the outflow channels may also be a factor

Aged↗
PubMed1980

Ocular ochronosis. Clinicopathological, histochemical, and ultrastructural studies.

Presented here are the clinical, histological, histochemical, and ultrastructural findings of an eye with notable ochronotic changes. Ochronotic pigment is seen by light microscopy as amber globules or fiber-like structures in the cornea, conjunctiva, and sclera combined with degenerated collagen. In the area of a previous injury the intense involvement of the cornea, which is usually not notably involved, indicates the role of preexisting degeneration for the development of clinically visible pigmentation. Although the ultrastructure of the ochronotic pigment is similar to melanin, the chemical behavior is different and, it seems, similar to elastin. Ultrastructurally, most of the pigment granules are extracellular, partly altering the collagen fibers and fibrocytes. The electron-microscopically observed four patterns of deposition are interpreted as stages in the development of ochronotic deposits, according to biochemical findings in the literature.

Aged↗
PubMed1980

Ultrastructural features of progressive idiopathic epiretinal membrane removed by vitreous surgery.

Clinical and electron microscopic studies of an idiopathic epiretinal membrane that was nonvascularized and progressive showed three types of cells: (1) predominant, fibrocyte-like cells; (2) macrophage-like cells; and (3) glial cells. Most of the abundant collagen showed characteristics of normal vitreous fibrils, although thicker collagen fibrils were also present. These ultrastructural findings, when compared with previously reported features of simple and secondary epiretinal membranes, suggest that clinically complicated epiretinal membranes are composed of more than one cell type, whereas simple epiretinal membranes consist only of glial cells. The fibrocyte-like and macrophage-like cells seen in our case were interpreted as being hyalocytes, rather than being derived from glial or retinal pigment epithelial cells. We support this interpretation by the ultrastructural features of the cells, the presence of abundant normal vitreous collagen, the biologic characteristics of hyalocytes as described by other investigators, and the absence of the ultrastructural features of glial or retinal pigment epithelial cells.

Adult↗
PubMedDate not supplied

Morphologic and clinical features of retrocorneal melanin pigmentation and pigmented pupillary membranes: review of 225 cases.

Observations based on clinical and histopathologic data from 200 consecutive cases of retrocorneal pigmentation by melanin-containing cells (RCP) and 25 cases of pigmented pupillary membranes (PPM) are reported. RCP was observed to be formed by four cell types, either alone or in combinations. The characteristic morphologic appearance of each cell type is described, and the significance and the predisposing factors for the various forms of RCP are outlined. RCP from endothelial-cell pigment phagocytosis, and in cases of resulting pigmented macrophages, was found to be a rather nonspecific reaction to release of pigment granules of iris pigment epithelium after surgical trauma, inflammation, and with the pigment dispersion syndrome. RCP from iris pigment epithelium was especially associated with anterior segment trauma with iris incarceration and peripheral anterior iris synechiae. This form was the least frequent. Most frequent in this series was RCP from iris stromal melanocytes. This seemed to be stimulated by surgical or accidental trauma and by corneal inflammation. Iris melanocytization of the anterior chamber angle and posterior corneal surface appeared to be related to the formation of retrocorneal fibrous tissue, the presence of anterior synechiae, and the development of secondary open-angle glaucoma. PPM are formed mostly by a combination of the pigmented cells of the iris. The predisposing conditions for formation of PPM were the same as for RCP. However, no correlation of implicated cell types and predisposing factors was detected. With these findings the importance of iris tissue, especially iris stromal melanocytes, in these basic reactions to anterior segment trauma or corneal inflammation is discussed.

Adolescent↗
PubMedDate not supplied

Macular edema and visual loss after macular pucker surgery with ICG-assisted internal limiting membrane peeling.

PURPOSE: To describe the occurrence of massive macular edema and visual loss after indocyanine green-assisted (ICG) macular pucker surgery. METHODS/RESULTS: A 74 years old female presented with a macular pucker and a hypertrophy of the retinal pigment epithelium (RPE) in her left eye. The preoperative visual acuity (VA) was 20/100. Surgery consisted of cataract extraction, lens implantation and standard pars plana vitrectomy with peeling of epiretinal tissue followed by the removal of the internal limiting membrane (ILM) remnants stained using a 0.05% ICG solution. One day after surgery, VA was counting fingers. There was an extensive macular edema and retinal thickening with hyperfluorescence during fluorescein angiography and pronounced autofluorescence using ICG filters. During follow up, the macular edema resolved completely, but VA decreased to 20/800 at six months postoperatively. There was a central scotoma and unstable fixation seen during microperimetry. DISCUSSION: This case report indicates that ICG might come into contact with bare retina if injected following removal of epiretinal membranes. Whether the observed RPE hypertrophy might have contributed to the pathogenesis of the adverse effect described remains hypothetical.

Aged↗