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Biomedical subjects

R C Tripathi

Publications and source records attributed to R C Tripathi.

At least 127 records · Page 7Linked to original sources
PubMed1981

Pigmentary macular degeneration with multifocal necrotizing encephalopathy.

A previously healthy 10-year-old girl suffered sudden, binocular visual deterioration. During the next few years her neurologic and visual condition progressively worsened and she developed hypertension, seizures, ataxia, and lactic acidemia, leading to death at the age of 16 years. Bilateral optic disk pallor was followed by the loss of the foveal reflex and pigmentary maculopathy, manifested as disorganization of the retinal layers, loss of ganglion cells, degeneration of the photoreceptors and nuclei, and irregular infiltration of the retina by pigment epithelial cells. The optic nerves and tracts showed central axonal loss. Bilateral, multifocal symmetric areas of cerebral atrophy and necrosis of the neuropil and neurons in the cerebral cortex, basal ganglia, and thalamus were observed; neurons persisted in the dorsal medulla, despite neuropil degeneration.

Brain Diseases↗
PubMed1981

Phakomatous choristoma of the lower eyelid with psammoma body formation: a light and electron microscopic study.

A firm, round tissue mass, measuring approximately 12 mm in diameter, was excised from a 5-month-old boy who had a history of a gradually enlarging swelling in the left lower nasal eyelid since birth. Histologically and ultrastructurally, the lesion appeared benign and was composed of a dense connective tissue stroma in which nests, lobules, tubules, cords, and sheets of large, pale-staining cuboidal and elongated epithelial cells were surrounded by an irregular, thick PAS-positive basement membrane having focal excrescences. The interior of the epithelial islands contained "bladder" cells, cellular debris, granuloamorphous material, and foci of dystrophic calcification; an unusual feature of the lesion was the formation of numerous psammoma bodies. Tumors of lenticular anlage are rare and probably result due to displacement of migration of the inferior lens placode cells; alternatively, it may originate from an additional locus of lens vesicle in the primitive surface ectoderm of the lower lid. The lesion enlarges because of the differentiation of the ectopic lenticular cells in an abortive attempt to form a lens within the extraocular and mesodermal environment of the lid.

Choristoma↗
PubMed1981

Effect of arachidonic acid on normal and dystrophic retinal pigment epithelium in tissue culture.

With carmine particles used as markers, no significant difference was observed between the phagocytic activity of 1- to 3-week-old confluent monolayer cultures of normal and dystrophic retinal pigment epithelial (RPE) cells harvested from 1-day-old Royal College of Surgeons rats. The phagocytic activity of both normal and dystrophic RPE was markedly suppressed in a medium containing 1 mg/ml arachidonic acid (AA), and the cells rapidly assumed a rounded profile. With 100 micrograms/ml AA, the phagocytic activity of dystrophic RPE was differentially reduced compared with that of the normal sample (p greater than or equal to 0.001); this effect was subsequently accompanied by a gradual change in the shape of the cells. Lower concentrations of AA (5 microgram/ml and below) did not produce a significant effect in either group.

Animals↗
PubMed1980

The pathology of soft contact lens spoilage.

Our study of a random series of more than 300 spoiled soft contact lenses reveals that virtually all lenses currently in use for daily or extended wear are subject to deterioration due to extraneous deposits, physical and chemical changes in the lens material, and microbial invasion. Common causes include ocular secretions, finger dirt and cosmetics, disinfecting and cleansing techniques, environmental factors, manufacturing defects and polymer impurities, mechanical stress and breakage, as well as aging and decay of the lens material. Mucoprotein-lipid deposits, with or without calcium, and calcareous deposits constitute the major forms of lens spoilage. Removal of encrusted deposits leaves surface irregularities and matrix defects which facilitate secondary spoilage including microbial invasion, and such lenses should be discarded. As virtually no soft lens material currently in use is "safe" for extended wear, the practitioner must carefully evaluated and follow his patients to identify those at risk of lens failure and spoilage complications. To eliminate spoilage, new lens materials and improved manufacturing techniques are needed. In the interim, for many patients, an inexpensive disposable soft lens which can be easily replaced, perhaps weekly or bi-weekly, may be the answer.

Acrylates↗
PubMed1980

Lowe's syndrome.

The histopathological manifestations in four eyes from two male patients with the oculo-cerebro-renal syndrome of Lowe included a small, discoid, cataractous lens, peculiar capsular and epithelial changes with aberrant formation of collagenous fibrous tissue, polar lenticular changes with anterior vitreous condensation, embryonic anterior chamber angle with anterior displacement of rudimentary ciliary processes, segmental hypoplasia of iris dilator muscle, and Lange's folds with peripheral retinal cystoid changes. Additional findings in one of the cases included bilateral corneal keloids, vitreous organization, hyalinized retinal vessels, and mild gliosis. We suggest that the congenital ocular abnormalities in Lowe's syndrome are related to an as yet unidentified, inherited enzymatic and/or biochemical defect, and that they progress further because of an abnormal aqueous humour environment. The role of aminoaciduria and mucopolysaccharidosis in the pathogenesis of systemic and ocular defects is discussed in the light of recent investigations.

Anterior Chamber↗
PubMed1980

A corneal transfixing irrigation/perfusion device: a new method for evacuation of hyphema.

For the surgical evacuation of hyphema, I adapted a corneal transfixing, irrigation/perfusion device, which essentially consists of an injection needle with holes on either sides of a central occlusion and connected to an inflow and an outflow system. This simple device offers notable advantages, including elimination of freely mobile needle tips that may endanger the structures bordering the anterior chamber, ease of maintenance of the desired level of intraocular pressure, freedom of the surgeon's hands for other surgical maneuvers, minimum trauma to the cornea with good tissue sealing at the entry and exit points of the needle, and minimal manipulation of the globe.

Corneal Diseases↗
PubMed1980

Changes in outflow facility in experimental hyphema.

To characterize the pathophysiology of hyphema clearance, we studied changes in the facility of outflow in experimental hyphema in freshly enucleated rabbit eyes. Hyphemas, with washed normal or sickled red cells (RBCs) (suspended in isotonic phosphate buffer to obtain a hematocrit value comparable to that of whole blood) and occupying 50% to 100% of the anterior chamber volume, caused a marked cell "crowding" in the chamber angle and an increase in the outflow resistance; the facility stabilized at a value 60% lower than the control (p = < 0.001). No significant change in outflow facility was observed in hyphemas of either RBC type occupying 25% of the anterior chamber volume (p = N.S.). Whole blood hyphema occupying 50% of the anterior chamber volume reduced the facility of outflow by 80% of the control mock aqueous value (p = < 0.001); a comparison with 50% hyphema produced by washed RBCs indicated a significant contribution by the plasma (fibrin) component (p = 0.0025) in increasing the resistance to outflow.

Anemia, Sickle Cell↗
PubMed1979

Hemoglobin A1 and diabetic retinopathy.

The levels of the minor hemoglobin A1 components were measured in a consecutive series of 102 diabetic patients who were extensively studied for signs of diabetic retinopathy. We found a statistically significant relationship between metabolic control, as reflected by the hemoglobin A1 level, and the severity of diabetic retinopathy in patients with diabetes diagnosed before 30 years of age (P less than or equal to .001). We did not demonstrate a significant correlation between metabolic control and the severity of retinopathy in patients with diabetes diagnosed after the age of 30 years. We found significantly more severe retinopathy among patients with longer duration of the disease, in men, in whites, in diabetics diagnosted before 30 years of age who were treated with lower insulin doses, and in obses patients with the onset of diabetes after the age of 30 years.

Adult↗
PubMed1979

A clinicopathologic study of autosomal dominant optic atrophy.

Of a family with 40 members, 12 had autosomal dominant optic atrophy. The affected members were aware of reduced vision from the first decade. Visual loss was moderate to severe, 6/12 (20/40) to 3/60 (10/200). The affected members showed similar centrocecal scotomata. Most affected patients had severe unclassified color defects. Electroretinography measurements were normal in all but one patient who had a small reduction in the scotopic response. The pathologic changes in a patient with autosomal dominant optic atrophy showed diffuse atrophy of the ganglion cell layer of the retina with a loss of myelin and nerve tissue within the optic nerves. We suggest that autosomal dominant atrophy is a primary degeneration of retinal ganglion cells.

Adult↗
PubMed1979

A new eye shield based on an optimized pinhole array.

The new eye shield described here incorporates the principles of a compound array that provides a significant improvement in vision (from hand movements to 20/100 or better) in a nonaccommodative eye, while retaining all other properties (protection, ventilation, reduction of glare) of eye shields used currently. It is recommended for routine use in patients after intraocular surgery and pupillary dilatation.

Eye Protective Devices↗