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Biomedical subjects

D G Cogan

Publications and source records attributed to D G Cogan.

At least 37 records · Page 2Linked to original sources
PubMed1984

Ocular abnormalities in abetalipoproteinemia. A clinicopathologic correlation.

The present paper documents the clinical characteristics and ocular pathology in a patient with abetalipoproteinemia. Noteworthy were: the predominant involvement of the posterior fundus characterized by a loss of photoreceptors; loss or attenuation of the pigment epithelium (producing a sharply demarcated white appearance on ophthalmoscopy); preservation of the submacular pigment epithelium with an excessive accumulation of lipofuscin (including bizarre laminar profiles by electron microscopy); invasion of the retina by macrophage-like pigmented cells. The retina and pigment epithelium in the periphery were morphologically normal. The patient died of a presumably unrelated brain tumor which was believed to have accounted for the terminal blindness and loss of ganglion cells in the retina.

Abetalipoproteinemia↗
PubMed1984

Gangliosidoses and the fetal retina.

Abnormal membranous cytoplasmic inclusions were found in the retinal ganglion cells of two fetuses with gangliosidosis. One was a documented case of incipient Tay-Sachs disease (Gm2) and the other a case of generalized gangliosidosis (Gm1). Both specimens were obtained iatrogenically in the 20th to 21st week of gestation after amniocentesis had indicated the enzyme deficiency.

Amniocentesis↗
PubMed1984

Comparison of retinal and cerebral vasculature in trypsin digest preparations.

The trypsin digestion technique for preparing flat mounts of the retinal capillary system was modified for comparable mounts of the cerebrocortical capillaries. These preparations, supplemented by electron microscopy, showed a basic similarity between the 2 systems, but the cortical capillaries have larger diameters, more abundant collateral channels, and less regularly spaced mural cells (intramural pericytes). The cortical capillaries did not show the right-angle branching of the precapillary arteriole characteristic of some retinal vessels, but they did show in the crotches of the branches an excess basement membrane that was not present in the retinal capillaries.

Capillaries↗
PubMed1984

The pathology of pingueculae in Gaucher's disease.

Several reports have noted an apparent association between pingueculae and Gaucher's disease and suggested that the yellow coloring of these lesions is attributable to Gaucher cells. The authors biopsied pingueculae from ten patients with this disorder and examined them by serial light microscopy and electron microscopy. They failed to find Gaucher cells in any specimen, but, as typical for pingueculae, the elastosis observed histologically could account for their yellow hue.

Conjunctiva↗
PubMed1984

NIH conference. Aldose reductase and complications of diabetes.

Tissues of the eye affected by diabetes are the lens, cornea, and retina. The lens becomes cataractous through osmotic swelling of its cortical fibers. Sorbitol, formed in the presence of aldose reductase, accumulates in the lens during hyperglycemia. Dulcitol similarly accumulates in the presence of galactosemia. Cataractogenesis in both cases can be prevented by inhibitors of aldose reductase. The efficacy of synthetic inhibitors differs in various tissues and species, but they react with aldose reductase at a common structural site. The most promising inhibitor is sorbinil . Diabetic retinopathy is similarly related to sorbitol accumulation and may be prevented or reversed by inhibition of aldose reductase. Healing of corneal wounds in diabetes is facilitated by enzyme inhibition. Retinal vasculopathy of diabetes is due to selective loss of the intramural pericytes that normally form structural elements in the retinal capillary walls. The vulnerability of these cells is due to their aldose reductase content. Whether inhibition of aldose reductase will prevent retinopathy is being tested in a randomized trial conducted by the National Eye Institute.

Aldehyde Reductase↗
PubMed1983

Leishmaniasis affecting the eyelids.

Leishman-Donovan bodies were recognized in the smear of a biopsy specimen from an eyelid ulcer. The infecting organisms were identified serologically as Leishmania braziliensis panamensis. The ulcer responded to pentavalent antimony. Ultrastructurally, the organisms had double-unit membranes, beneath which lay a palisade of microtubules. At one end of the organism, there was a rudimentary flagellum; at the other, the nucleus. A kinetoplast basal complex separated the two.

Adult↗
PubMed1983

Clinical studies of color vision with Gunkel's chromagraph.

Color thresholds in a series of patients with local or systemic diseases were determined by a chromagraph method and subjected to computer analysis. When compared with normal persons, those with optic nerve disease (multiple sclerosis, optic neuritis, and optic atrophy) showed an overall weakness for all colors (enlarged neutral areas), with an additional specific defect in the orange-cyan (greenish blue) axis. Those with the two retinal diseases studied (macular degeneration and retinitis pigmentosa) also showed threshold elevation for all colors, but with a special defect in the yellow-blue axis. The general elevation was greater for patients with retinitis pigmentosa than for those with macular degeneration, regardless of the visual acuity. In patients undergoing treatment for systemic lupus erythematosus and rheumatoid arthritis, there was a mild elevation of the color threshold, especially for yellow.

Arthritis, Rheumatoid↗
PubMed1983

Macula halo syndrome. Variant of Niemann-Pick disease.

The macula halo syndrome is the name proposed to describe patients with a unique ring-form opacity about the foveolas and a histiocytic storage disease. Since sphingomyelinase deficiency has now been found in the three patients in whom it was sought (including two in the present report), the entity may be classified as a variant of Niemann-Pick disease. A secondary hyperlipidemia may also be present. The macula halos consisting of symmetric crystalloid opacities with little or no visual impairment are pathognomonic of the entity.

Adult↗
PubMed1983

The familial occurrence of cutaneous melanoma, intraocular melanoma, and the dysplastic nevus syndrome.

The occurrence of cutaneous melanoma and intraocular melanoma as double primary cancers in the same patient and in different members of the same family has suggested that these two forms of melanoma are etiologically related. It is theoretically possible that the link between these two pigment cell malignancies may be the dysplastic nevus syndrome, and patients with the dysplastic nevus syndrome may have an increased risk of intraocular melanoma and cutaneous melanoma. We studied two new kindreds in which cutaneous melanoma, intraocular melanoma, and the dysplastic nevus syndrome occurred and conducted neuro-ophthalmologic examinations of 26 patients with hereditary cutaneous melanoma or the dysplastic nevus syndrome, or both. In the one family studied in detail, the cutaneous melanoma predisposition came from the paternal bloodline, whereas the intraocular melanoma occurred in the maternal bloodline. The ophthalmologic examinations disclosed neither intraocular melanoma nor suspicious or atypical choroidal nevi. Our limited data suggested that the association of intraocular melanoma with cutaneous melanoma and dysplastic nevus syndrome may be coincidental.

Adult↗
PubMed1983

The pathology of idiopathic midline destructive disease (IMDD) in the eyelid.

Subcutaneous eyelid and brow nodules were noted in a 25-year-old man who, at the age of 14 years, had developed the central facial and upper airway necrosis characteristic of idiopathic midline destructive disease (IMDD). One large nodule was located near the lateral canthus rather than a midline position. Insofar as we know, this report would constitute the first evidence of IMDD in the eyelids and brow in the absence of orbital disease.

Adult↗
PubMed1983

Blink-saccade synkinesis.

We studied two patients who could make saccades of normal velocity and amplitude only in association with a simultaneous blink. In one patient, the initiation of saccades was also facilitated by blinks. Both patients had signs of cerebellar or brainstem dysfunction, suggesting a posterior fossa localization for blink facilitation of saccadic velocity and amplitude.

Adult↗
PubMed1982

Ocular signs of cerebellar disease.

Ocular signs of cerebellar disease have been increasingly appreciated with the advent of means for quantitative recording of eye movements. The graphs in this article illustrate ocular flutter, dysmetria, abnormal (nonsmooth) pursuit, instability of fixation, faulty vestibular suppression, impaired optokinetic response, end-position nystagmus, and rebound nystagmus. The signs may be categorized as follows: (1) proprioceptive abnormalities manifest by flutter, dysmetria, and instability of gaze and (2) defects of vision-dependent functions manifest by abnormalities of pursuit, vestibular suppression, optokinetic response, and nystagmus.

Basal Ganglia↗
PubMed1982

Culture-proven cytomegalovirus retinitis in a homosexual man with the acquired immunodeficiency syndrome.

A 35-year-old homosexual man with cytomegalovirus viremia developed retinitis. He also had a new syndrome consisting of a persistent T-lymphocyte deficit, pneumocystis pneumonia, recurrent Candida albicans esophagitis, skin ulcerations caused by herpes simplex virus, Type 2, disseminated Mycobacterium avium-intracellulare infection, and molluscum contagiosum. Histopathologic examination revealed bilateral necrotizing retinitis with virions in retinal, choroidal, and optic nerve tissues. Postmortem cultures of retina and vitreous were positive for cytomegalovirus.

Acquired Immunodeficiency Syndrome↗