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Biomedical subjects

T M Aaberg

Publications and source records attributed to T M Aaberg.

At least 127 records · Page 7Linked to original sources
PubMed1979

Choroidal edema associated with retinal detachment repair: experimental and clinical correlation.

Experimental owl monkey data and prospective clinical data is presented, demonstrating the correlation of serous-choroidal edema with the extent of vortex obstruction and the additive factors of sudden hypotony from drainage and cryotherapy. Older eyes are more susceptible for developing this phenomenon of choroidal edema. The extreme extent of vortex venous stasis is that of venous stasis anterior segment ischemia demonstrated in two clinical cases.

Adult↗
PubMed1978

Intraocular sulfur hexafluoride and octofluorocyclobutane. Effects on intraocular pressure and vitreous volume.

Partial vitrectomies were performed on rabbits and the amount of vitreous removed was replaced with either 100% sulfur hexafluoride (SF6), 100% octofluorocyclobutane (freon-C318), 40% SF6, or air. Intraocular pressure and vitreous volume were determined. Replacing 40% of the initial vitreous volume with either 100% SF6 or 100% octofluorocyclobutane caused an increase over 20 mm Hg in the IOP with an associated loss of the remaining vitreous, whereas replacement with 40% SF6 or air caused no significant increase in IOP. Replacement with 40% SF6 caused a significant loss of the remaining vitreous, whereas the air replacement did not result in a vitreous loss. The experiments were repeated substituting only 20% of initial vitreous volume with 100% SF6 and 100% octofluorocyclobutane. Using this amount of SF6 and octofluorocyclobutane, the IOP did not increase but an associated vitreous loss occurred equal to twice the amount of SF6 injected and three times the amount of octofluorocyclobutane injected.

Air↗
PubMed1978

Progressive chorioretinopathy after receiving thioridazine.

A distinctive appearance of the ocular fundus as a late complication of high doses of orally administered thioridazine hydrochloride (Mellaril) is described. Discrete nummular areas of loss of retinal pigment epithelium (RPE) extended from the posterior pole to the midperiphery. Fluorescein angiography demonstrated loss of choriocapillaris in these zones. Atrophy of the remaining RPE was progressive, with advancement of the edges of the atrophic zones and breakdown of bridges of RPE separating them. Atrophy occurred after discontinuation of the drug and advanced without further exposure to it. Dark adaptation, the electroretinogram, and the electro-oculogram were abnormal in the late stages. Central visual acuity remained relatively good.

Adult↗
PubMed1978

Reticular dystrophy of the retinal pigment epithelium. A clinical and electrophysiologic study of three generations.

Reticular dystrophy of the retinal pigment epithelium is characterized by a posterior pattern of pigment clumping like a "fishnet with knots." Four patients in three successive generations were seen with typical reticular dystrophy. A fifth patient had abnormal dark adaptation. In this family reticular dystrophy was characterized by the typical reticular pigmentary pattern, good visual acuity, normal electroretinographic findings, abnormal electro-oculographic findings, and abnormal dark adaptation. The pedigree indicates autosomal dominance as the inheritance pattern.

Adolescent↗
PubMed1978

Astrocytic hamartoma of the retina not associated with tuberous sclerosis.

A 6-year-old boy had a peripapillary lesion diagnosed as retinal astrocytic hamartoma, which was not associated with tuberous sclerosis, neurofibromatosis, or intraocular extension of a glioma. The patient was observed for nine years, during which time the lesion grew significantly. Because of this growth and the evidence of proximal optic nerve involvement on computed tomography, radiation therapy was administered with a resultant marked reduction in visual acuity. The eye was subsequently enucleated. The enucleated eye was studied by both light and transmission electron microscopy. The specimen had a retinal astrocytic hamartoma with sparse vascularization and only superficial optic nerve involvement. Additionally, it revealed optic nerve drusen in varying stages of development, significant accumulations of subretinal macrophages, and an almost total loss of retinal outer segments with the preservation of the retinal pigment epithelium.

Adolescent↗
PubMed1978

Pigment epithelial proliferation in human retinal detachment with massive periretinal proliferation.

Biopsy specimens from vitreous and preretinal membranes, obtained during vitreous surgery from 39 human eyes suffering from massive periretinal proliferation, were examined electron-microscopically. Analysis of the cellular membranes demonstrated mostly cells with epithelial characteristics: polarization of the cells, basal lamina formation, specialized cellular junctions, and microvilli formation. These epithelioid cells contained prominent rough endoplasmic reticulum, glycogen deposits, a multitude of cytoplasmic filaments, some resembling myofilaments, and nonmembrane bound, sometimes wedge-shaped pigment granules. Macrophages were interspersed in the membranes. There was a striking similarity of these findings to those of an experimental model of retinal detachment in owl monkeys, We concluded that most likely the described cells derived from cells of pigment epithelial origin.

Cell Division↗
PubMed1978

The prevalence of HLA-B7 in presumed ocular histoplasmosis.

Eighteen patients with the presumed ocular histoplasmosis syndrome were typed for HLA histocompatability antigens and 78% were found to have the B7 antigen. This data implies an underlying immunogenic predisposition to the development of the clinical eye findings and active posterior pole lesions in the presumed ocular histoplasmosis syndrome. It is likely that some feature of the immune system of these patients renders them more susceptible either to the initial infection or to a later activation of posterior pole lesions mediated through immunologic mechanisms.

Eye Diseases↗
PubMed1978

Late complications of pars plana vitreous surgery.

Late complications (following hospital discharge) occurring in 206 consecutive pars plana vitrectomy cases, comprising a subgroup of 100 consecutive cases for diabetic retinopathy, are reviewed. Ocular hypertension, occurring as neovascular glaucoma, was present in 18% of diabetic eyes, but other causes of ocular hypertension gave an overall incidence of 26%. Electron microscopy, scanning, and transmission photographs document the devastating ocular neovascularization occurring postvitrectomy.

Adult↗
PubMed1978

Senile macular degeneration and geographic atrophy of the retinal pigment epithelium.

The case is reported of a man who had oval areas of atrophy of the retinal pigment epithelium in paracentral areas which previously had heavy concentrations of drusen OU. This supports the suggestion by others that atrophy of the RPE in senile macular disease may in some cases occur in the absence of previous serous detachment of the RPE.

Atrophy↗
PubMed1977

Glial cell proliferation in human retinal detachment with massive periretinal proliferation.

By transmission electron microscopy we studied 38 epiretinal membranes obtained from human eyes by vitrectomy operation in rhegmatogenous retinal detachment. Two of the membranes were composed of closely packed glial cell processes. The cytoplasm of the glial cell processes in both membranes contained little besides loosely packed filaments and microtubules. Microvilli protruded from the cells at the vitreal surface of one of the membranes. Junctional complexes were present between the cells only at the vitreal surface. In the other glial membrane, microvilli extended into a duct-like structure with junctional complexes sealing the lumen. A discontinuous basal lamina was laid down by cell processes at the retinal side of the membranes. Similar glial membranes, formed by migration and proliferation of astrocytes from the retina, were seen in owl monkeys with experimental and naturally occurring retinal detachment. A new epiretinal membrane (reformed in one of the eyes from which a dense glial membrane had been removed three weeks previously), was composed primarily of single large cells with extensively developed rough endoplasmic reticulum. The new cells were surrounded by collagen, fine fibrillar material, and fibrin. The new membrane also contained free pigment granules and pigment-containing macrophages. Additionally, we observed spicule-like crystals between the cells in the glial membrane specimens, identified as calcium phosphates by energy-dispersive x-ray analysis.

Animals↗
PubMed1977

Hemorrhagic peripapillary lesions in presumed ocular histoplasmosis.

Eight eyes of five patients with hemorrhagic peripapillary histoplasmosis demonstrated prolonged symptomatic periods and recurrent bleeding episodes, although final visual acuity was equal to or better than 6/12 (20/40) in five eyes (63%). Fluorescein angiography demonstrated new subretinal neovascular growth at the margins of atrophic scars. In the late stages additional retinal pigment epithelium was lost and a white subretinal mass developed adjacent to the atrophic zone. Argon laser photocoagulation was used in two cases to destroy this neovascular tissue, but caused a permanent arcuate defect in one.

Adult↗
PubMed1977

Necrotizing vaso-occlusive retinitis.

We studied two adult patients with fulminating, necrotizing vaso-occlusive retinitis, and documented the progressive course of retinal necrosis, vitreoretinal interface contraction, and consequent retinal detachment. The systemic criteria for Behçet's disease were present in one patient, and partially fulfilled in the second.

Adult↗
PubMed1977

Unusual ocular presentation of acute toxoplasmosis.

Four patients with toxoplasmosis are reported with unusual presenting ocular lesions. One patient had an active lesion that appeared to involve the optic nerve as well as focal toxoplasmosis chorioretinitis at the macula. A second patient had a pale optic nerve in association with the classical chorioretinal scars of toxoplasmosis. The third patient had toxoplasmosis chorioretinitis of the macula with subretinal neovascularisation. The fourth patient had a branch artery occlusion complicating acute retinitis.

Acute Disease↗
PubMed1977

Argon laser photocoagulation treatment of diabetic cystoid maculopathy.

Forty-one patients with diabetic cystoid macular edema were treated with argon laser photocoagulation and followed for a mean period of 22 months. The fellow eye was held as control. In the treated group (33 eyes), 6 had an improvement in visual acuity (greater than 2 lines), 19 had visual acuity which remained the same (+/- 1 line), and 8 had a decrease in visual acuity (more than 2 lines). In the control group (33 eyes untreated), 18 had a visual acuity which remained the same, one had an improvement in visual acuity (greater than 2 lines) and 14 had a decrease (greater than 2 lines) in visual acuity. The control eyes of 14 patients were treated because of significant reduction in visual acuity. Although the general tendency toward stabilization in the treated group and toward deterioration in the untreated group was definitely observed, statistical evaluation did not show a significant difference between the 2 groups. Occasionally, patients with cystoid in the control eye cleared spontaneously without treatment.

Adult↗
PubMed1976

The use of solid soft silicone rubber exoplants in retinal detachment surgery.

A method of retinal detachment surgery utilizing soft solid silicone rubber exoplants is described along with its use in typical cases. Solid silicone rubber, long used as a scleral implant, is a well-tolerated exoplant scleral buckling material which has been found to provide excellent long-term results. The surgical procedure described is relatively short in duration and has a minimum of operative and postoperative complications.

Humans↗
PubMed1975

Experimental serous and hemorrhagic uveal edema associated with retinal detachment surgery.

A study of the effects of hypotony, cryotherapy as the adhesive modality and vortex system obstruction in repair of experimental retinal detachment in the owl monkey is reported. The presence of serous uveal edema (detachment) correlated mainly with the degree of cortex obstruction. Hemorrhagic extravasation appeared to be a more exaggerated manifestation of such vascular stasis.

Animals↗