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Biomedical subjects

J Sebag

Publications and source records attributed to J Sebag.

At least 73 records · Page 4Linked to original sources
PubMed1984

The Alström syndrome: ophthalmic histopathology and retinal ultrastructure.

A case of pigmentary retinal degeneration causing blindness in early childhood, progressive neurosensory hearing loss, diabetes mellitus, acanthosis nigricans, hypogonadism with normal secondary sex characteristics, and kyphoscoliosis without polydactyly and with no mental retardation is reported. The results of endocrinological studies, karyotype analysis, and digital dermatoglyphics supported the clinical diagnosis of the Alström syndrome. The patient had small globes, bilateral posterior subcapsular cataracts, lacy vacuolation of the iris, ciliary process hyalinisation, unilateral asteroid hyalosis, total absence of rods and cones, intraretinal melanin pigment, retinal pigment epithelium atrophy, focal chorioretinal fusion, preretinal fibrosis, bilateral giant optic disc drusen, and optic nerve atrophy. Electron microscopy of the retina demonstrated large numbers of melanolysosomes, numerous folds of basement membrane material, disruption of Bruch's membrane, and numerous bundles of extracellular collagen fibrils in the retinal pigment epithelium.

Adult↗
PubMed1983

Aberrant regeneration of the third nerve following orbital trauma. Synkinesis of the iris sphincter.

A patient had aberrant regeneration of the inferior branch of the third nerve following penetrating orbital trauma. Examination of the right eye showed no light perception and a pupil that was nonreactive to accommodation, direct, and consensual light stimuli. However, on downgaze, there was marked constriction of the pupil in the blind eye. The phenomenon of oculomotor misdirection is discussed with respect to aberrant regeneration, ephaptic transmission, chromatolysis-induced nuclear reorganization, and recent neurophysiologic studies. Our case provides strong support for the concept of peripheral aberrant regeneration as the mechanism underlying some instances of oculomotor misdirection after third-nerve palsy.

Cranial Nerve Diseases↗
PubMed1983

Orbital fistula. Causes and treatment of 20 cases.

A retrospective analysis of 20 cases of orbital fistula in Shanghai showed the causes to be trauma with foreign-body retention, osteomyelitis, mucocele, and dermoid cyst. Half the patients were children younger than 10 years old. Cicatricial ectropion, ptosis, and extraocular motility disturbance constituted the common clinical findings. Treatment according to the various causes included surgical removal of the foreign body, oral administration of antibiotics combined with local irrigation, radical extraction of all the epithelium lining the fistula, and excision of the fistula.

Adolescent↗
PubMed1983

Complete bilateral internal carotid artery occlusion in a young man.

Partial or complete occlusion of the internal carotid artery is a familiar consequence of severe atherosclerosis seen in the elderly. Complete obstruction of both internal carotids is rare, particularly in the young or middle-aged. The rapid onset of bilateral internal carotid occlusion would be expected to produce devastating neurological sequelae and probably not be compatible with survival. We present a case of a young man with complete obstruction of both internal carotid arteries whose presenting symptoms were those of a visual field cut. The history suggests that the carotid occlusion occurred as a result of blunt trauma. The patient had no known predisposition to vascular abnormalities (no history of hypertension, hyperlipidemia, signs of systematic arteriosclerosis or vasculitis, and an unremarkable family history for vascular abnormalities). Computerized tomography revealed an infarct in his right parietal lobe. Angiography demonstrated complete occlusion of both internal carotid arteries and the right posterior communicating artery and failed to disclose the development of extensive collatorals, adding further evidence to the acuteness of the occlusion. The patient was followed by noninvasive studies and in the subsequent year showed marked neurological and ophthalmological improvement.

Adult↗
PubMed1983

Pathologic processing of vitrectomy specimens. A comparison of pathologic findings with celloidin bag and cytocentrifugation preparation of 102 vitrectomy specimens.

Specimens obtained from 102 vitrectomies were processed by cytocentrifugation and celloidin bag techniques. The histopathology obtained with each procedure was compared with respect to cellular and tissue findings. Forty-five percent of cases had identical findings by the two techniques. Quantitative analysis of the discrepancies revealed better cellular recovery and identification by cytocentrifugation, and similar rates for the recovery and identification of tissue elements. Qualitative analysis showed better demonstration of tissue histopathology using celloidin bag thin sections. Thus, pathologic analysis was more complete when the two techniques were used together than when either was used alone.

Centrifugation↗
PubMed1983

The induction of retinal detachment.

The induction of retinal detachment is dependent upon several factors whose relative importance remains controversial. These factors are retinal breaks, often associated with vitreous traction, inertial forces and changes in chorioretinal adhesion. Retinal breaks may be classified as holes, tears and dialyses. The relation to the vitreous base is an important prognostic indicator. Once a retinal break has occurred, inertial forces disturb the normal vitreo-retinal association. At that point, the development of a clinical detachment also depends upon loosening of the normal chorioretinal adhesion. Myopia and aphakia are important predisposing factors. The presence of preretinal membranes is a precipitating factor for recurrent retinal detachment. The high success rate of current surgical techniques (85 per cent) is mainly related to a better understanding of the mechanisms leading to retinal detachment.

Adhesiveness↗
PubMed1982

Pseudochalazion of the upper lid due to hard contact lens embedding -- case reports and literature review.

Two cases of pseudochalazion formation secondary to hard contact lens embedding are reported. In all previously reported cases a lump, swelling, mucopurulence, and ptosis were the most common presenting symptoms. Embedding usually occurred concave to the globe in the supratarsal region. The cases reported herein are unique in that the location of one lens was beneath the tarsal conjunctiva, and in the second case there was spontaneous release of the lens after four months of embedding.

Adolescent↗
PubMed1977

Effect of temperature on bacterial killing by serum and by polymorphonuclear leukocytes.

Bacterial killing by serum alone and by polymorphonuclear )PMN) leukocytes was studied at 37 degrees C and compared with killing at 39 and 41 degrees C. The test organisms for serum killing were Staphylococcus aureus 502A (serum resistant) and Escherichia coli O14 (serum sensitive). The organisms used in PMN killing tests were Streptococcus pneumoniae type 29 and E. coli O86.S aureus was not killed by serum alone at any temperature. Changes in temperature did not affect the rate of serum killing of E. coli O14 for the first 60 min, but by 90 and 120 min there was a discrepancy with continued killing at 37 degrees C, but no further killing at 39 and 41 degrees C. PMN phagocytic killing of the pneumococcus was enhanced at 39 degrees C compared with 37 degrees C, and phagocytic killing of E. coli O86 was decreased at 41 degrees C when compared with 37 degrees C. Therefore, it appears that under certain circumstances fever may aid the host PMNs in destroying organisms, whereas under other circumstances it may interfere with such destruction.

Blood Bactericidal Activity↗
PubMed1975

Decision-making in clinical practice: application of predictors, indicators and indices to the medical history obtained by a self-administered questionnaire.

A theoretical description of predictors, indicators, and health indices was presented in an earlier paper (Hall and Sebag, 1974). The application of predictors, indicators and health indices--including dynamic health indices--to anamnestic data obtained by a self-administered questionnaire is presented herein. Predictors and indicators showed a varying degree of 'decision-making significance' in the 122 questions examined. The health index distinguished between diagnosed individuals and those receiving no diagnosis(es). The dynamic health index was found to reflect changes in the health status of an individual over a period of time.

Decision Making↗
PubMed1975

Relationship between work environment and anamnestic health status. Use of predictors, indicators and indices for the evaluation of medical and environmental factors.

Experience with computerized medical record systems in handling medical data in hospital and health screening environments has led to the development of a new approach to the evaluation of medical data. Predictors and indicators quantify the "information value" of medical data and can, theoretically, do so for all types of data. This paper describes the methodology and presents the results obtained when the technique was applied to the anamnestic data of the medical history and environmental data about the conditions in the work environment. Over 4,000 individuals who underwent multiphasic health screening were used as a data base for this study. From these 4,000 persons 3,164 were used for the calculation of anamnestic predictors and indicators and 1,013 for the environmental predictors and indicators. Anamnestic environmental indices were calculated upon 77 test individuals so as to correlate the association and dependence of the two indices.

Environmental Exposure↗
PubMedDate not supplied

Diabetic retinopathy. Pathogenesis and the role of retina-derived growth factor in angiogenesis.

Diabetic retinopathy results from a combination of systemic and ocular abnormalities. Vasodilation, basement membrane pathology, microaneurysms, abnormal blood flow and tissue oxygenation, connective tissue abnormalities, and retinal ischemia are all components of early diabetic retinopathy. The pathogenesis of neovascularization is discussed with respect to the effects of vasodilation, vascular leakage, vitreous changes, and retinal ischemia. The evidence supporting Michaelson's hypothesis that a chemical messenger from the retina provides the stimulus for neovascularization is cited. The sequence of events involved in angiogenesis are cellular and basement membrane changes, endothelial cell migration, endothelial cell proliferation, and vessel formation. The experimental evidence in support of a role for retina-derived growth factor as a mediator of these cellular events is reviewed.

Basement Membrane↗