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Biomedical subjects

E D Wolf

Publications and source records attributed to E D Wolf.

28 records · Page 2Linked to original sources

Cataracts in cichlid fish.

Bilateral cataracts were detected in a group of aquarium-raised tilapia (Sarotherodon mossambicus). Vision impairment was manifested as random swimming into objects, but the fish appeared to function normally otherwise. Most of the lens was opaque, with the outer extent of the cortex and subcapsular region remaining transparent. Skeletal abnormalities, ie, deformed fins, abnormal jaws, and curvature of the spine, were observed in affected individuals. Histologically, there was progressive degeneration of the cataractous portion as the affected fish matured. Preliminary breeding experiments indicated that the condition may be inherited.

Animals↗

Absence of sprouting by retinogeniculate axons after chronic focal lesions in the adult cat retina.

Focal lesions were placed in the retina of adult cats in order to denervate partially the laminae of the lateral geniculate nucleus (LGN). Retinogeniculate projections were assessed after survival times of from 5 days to 2 years by means of either reduced silver staining for degeneration or autoradiographic labelling. Filling of the lesion-denervated zones by 'sprouts' from the intact retinofugal fibers was not observed, even in the brains of animals with long-term lesions. It was concluded that the retinogeniculate projection in adult cat does not display any significant ability to sprout into denervated regions.

Animals↗

Chorioretinal vascular anastomoses resulting from photocoagulation in cynomolgus monkeys.

We studied the effects of intense argon laser photocoagulation in cynomolgus monkeys to determine whether or not anastomosis between the choroidal circulation and the major retinal arterioles could be produced. Chorioretinal vascular anastomosis occurred in nine of 19 sites in which photocoagulation was intense enough to occlude a major retinal arteriole and create disruption between the choroidal and retinal vasculatures. Anastomosis was seen by fluorescein angiography during the healing phase after treatment--none occurred earlier than seven weeks after photocoagulation. As a result of the anastomosis, previously nonperfused retinal blood vessels became reperfused (with choroidal blood). This model suggests future applicability in reperfusing segments of retinal arterioles or venules that have been obstructed by naturally occurring pathologic processes. The remaining ten treated sites showed no anastomosis, even through histologic studies showed that photocoagulation produced chorioretinal disruption and hemorrhage. None of the eyes developed neovascularization.

Animals↗

An inherited retinopathy in collies. A light and electron microscopic study.

A recessively inherited retinopathy in collies aged 8 to 189 days was studied by light and electron microscopy. The disease is produced when the outer segments of rods and cones fail to develop normally. Retinal pigment epithelial changes found in several litters appeared to form a separate disease entity. We compared the collie retinopathy with other canine models and the collie ectasia syndrome.

Animals↗

Rod-cone dysplasia in the collie.

Rod-cone dysplasia in the Collie was studied. Night blindness developed early (6 wk) and progressed to nearly total blindness by 1 year of age. Tapetal hyper-reflectivity, vessel attenuation, and optic nerve pallor were clinically evident by 6 months of age. Electroretinography demonstrated markedly reduced retinal response as early as 16 days of age. The results of selective breedings conformed to a single recessive pattern of inheritance.

Animals↗

Ophthalmic manifestations of induced sickling of erythrocytes in Japanese sika deer (Cervus nippon).

Nine female Japanese sika deer (Cervus nippon) were used in a total of 25 experiments in which sickling was chemically induced. During these experiments, color fundic and color fluorescein photographs were taken. Fundic changes included retinal vascular attenuation, blood column pallor, and decreased tapetal reflectivity. These changes were most likely directly associated with a decreased hematocrit and a generalized shocklike condition. Three deer had a congested appearance in retinal blood vessels and tapetum lucidum. Two of the 3 deer developed serous detachment of the retina. These changes seemingly were associated with severe venous statis; all 3 deer died shortly after the experiment was terminated. These experiments yielded data only for the acutely affected deer. None of the ocular changes could be considered the result of chronic sickling because of the reversal of sickling that occurred despite continued intravenous administration of bicarbonate. None of the deer developed ocular changes characteristic of sickle cell retinopathy in human beings. The changes in human beings probably result from continued stress and prolongation of sickling, and especially from a multiplicity of repeated severe episodes of sickling occurring over many years.

Alkalosis↗

In vivo erythrocyte sickling in the Japanese sika deer (Cervus nippon): methodology.

The Japanese sika deep (Cervus nippon) proved to be a suitable animal model for the study of acute phases of in vivo erythrocyte sickling. Ophthalmologic studies can be conducted during or after 1 to 6 hours of effective in vivo sickling. Intravenous administration of 1.75 to 3.5% sodium bicarbonate solution at a rate of 500 to 1,000 ml per hour produced a transient state of alkalosis and in vivo erythrocyte sickling in the sika deer. The percentage of sickled erythrocytes increased as the blood pH increased. Concurrently, the packed cell volume decreased. Sickling was enhanced by 100% oxygen ventilation after endotracheal intubation and light anesthetization. After the induction of erythrocyte sickling, a sickling-reversal phenomenon occurred despite continued bicarbonate administration. During the course of this reversal, the percentage of sickled erythrocytes steadily decreased, the venous blood pH decreased, and the packed cell volume slowly increased. Because of the sickling-reversal phenomenon, chronic erythrocyte sickling was not achieved.

Alkalosis↗

Cone-rod dystrophy in the Guinea baboon.

Three stages of macular degeneration associated with diffuse cone-rod dystrophy have been described in a Guinea baboon (P papio) colony. Clinically, the affected animals displayed abnormal behavior associated with decreased vision. Ophthalmoscopically, the lesion in the macula was the only change observable in early cases; retinal vessel attenuation and optic disc pallor were seen only in the advanced cases. The hyperfluorescence of the maculae was the result of loss of pigment in the pigmented epithelium. Electrophysiology supported a cone-rod sequence of this retinal dystrophy. Histologic examination confirmed the theory that the dystrophy began in the cone outer segment but eventually involved all the photoreceptors.

Animals↗