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Biomedical subjects

J M Risco

Publications and source records attributed to J M Risco.

At least 19 recordsLinked to original sources
PubMed1998

Keratoconjunctivitis sicca associated with achalasia of the cardia, adrenocortical insufficiency, and lacrimal gland degeneration: Keratoconjunctivitis sicca secondary to lacrimal gland degeneration may parallel degenerative changes in esophageal and adrenocortical function.

OBJECTIVE/DESIGN: This study aimed to examine and describe three siblings with alacrima, the eldest of whom had associated achalasia and adrenocortical insufficiency. PARTICIPANTS: Three affected siblings and four age-matched control subjects participated. INTERVENTION/MAIN OUTCOME MEASURES: The three children underwent complete ophthalmologic examinations; computed tomographic scanning of brain, orbit, chest, and abdomen; and measurement of serum cortisol. All three were subjected to a short synacthen challenge. Lacrimal gland biopsies were performed on the two younger subjects, and specimens were studied by light and electron microscopy. RESULTS: All three children showed virtually absent tear secretion as tested by the Schirmer test. The resulting keratopathy was most severe in the oldest child, who developed bilateral corneal melting. The two younger children showed interpalpebral corneal staining with rose bengal. All three children improved after punctal occlusion. Addison's disease was present in the oldest child. Computed tomographic scanning showed absent lacrimal and shrunken adrenal glands in association with achalasia of the cardia in the oldest child. The lacrimal glands were found to be reduced in size in the next eldest child. When evaluated by electron microscopy, the lacrimal gland biopsy specimens from the two younger children showed neuronal degeneration associated with depletion of secretory granules in the acinar cells. CONCLUSION: In this disease, radiologic evidence of reducing lacrimal gland size with increasing age could represent a degenerative process. This may be paralleled by other signs and the possibility of adrenocortical insufficiency and achalasia of the cardia should be investigated in all children presenting with dry eyes. These children appear to have a progressive neuronal disease.

Adrenal Cortex↗
PubMed1995

Congenital hereditary endothelial dystrophy associated with glaucoma.

BACKGROUND: Three children, ranging in age from 2 to 6 months, had diffuse and homogeneously opaque corneas, clinically consistent with congenital hereditary endothelial dystrophy. Bilateral elevated intraocular pressure (IOP) was a feature in all three children. METHODS: Initially, all patients underwent glaucoma surgery to reduce IOP. Subsequently, a penetrating keratoplasty was performed in one eye of each patient to clear the visual axis. The excised corneal button was examined by light microscopy and by transmission and scanning electron microscopy. RESULTS: Postoperatively, all patients maintained clear corneal grafts. Results of histopathologic examination showed an absence of the endothelial cell layer in all patients. The presence of a variably thick collagenous layer posterior to the anterior banded zone of Descemet's membrane and the absence of endothelial cells were noted on transmission electron microscopy. Scanning electron microscopy confirmed absent, or scanty, and abnormal endothelial cells. CONCLUSION: The authors describe three patients with a clear association between congenital glaucoma and congenital hereditary endothelial dystrophy. This combination should be suspected where persistent and total corneal opacification fails to resolve after normalization of IOP.

Cataract↗
PubMed1994

A case of corneal keloid: clinical, surgical, pathological, and ultrastructural characteristics.

A 69-year-old patient developed a localised, whitish, elevated, corneal lesion with a smooth and glistening surface following trauma, without evidence of corneal perforation. Twelve months later, the lesion showed evidence of slow growth. An excisional biopsy was then performed. Histopathologically, the lesion was covered by non-keratinised squamous epithelium and was comprised of randomly oriented collagen fibres containing active fibroblasts. Blood vessels were noted deep in the lesion. Ultrastructurally, the cell population was formed by fibroblasts and myofibroblasts, similar to keloids of the skin. The clinical, pathological, and ultrastructural features of the corneal lesion are compatible with a corneal keloid.

Aged↗
PubMed1992

Ultrastructural alterations in the endothelium in a patient with topical anesthetic abuse keratopathy.

A 40-year-old patient frequently self-administered topical oxybuprocaine drops for approximately 7 days after bilateral ultraviolet-light keratitis. Initially, he developed bilateral chronic epithelial defects with diffuse stromal infiltration and edema. After a protracted initial healing period, the patient underwent a penetrating keratoplasty in one eye because of significant corneal scarring. Pathologically, the corneal button revealed scarring and thinning of the central stroma. Results of scanning electron microscopy showed endothelial polymorphism, focal endothelial necrosis, and numerous filamentous processes emanating from abnormally enlarged intercellular gaps. Results of transmission electron microscopy showed markedly attenuated to absent apical cell attachments at the endothelial intercellular junction. Abuse of oxybuprocaine appears to produce irreversible damage to the apical cell attachments at the level of the corneal endothelial cells.

Administration, Topical↗
PubMed1991

Epikeratoplasty for keratoglobus associated with blue sclera.

Patients with keratoglobus and blue sclera as part of a generalized connective tissue disorder are at a high risk of developing corneal perforations either spontaneously or after mild trauma. Six patients (6 eyes) between the ages of 2 and 16 years of age (mean, 7.5 years) with keratoglobus, blue sclera, hypermobile joints, and consanguineous parents were treated by epikeratoplasty, using commercially prepared 12.5-mm lenticules. Surgery was performed for tectonic support and/or visual improvement and was successful in five of six patients with a follow-up period of 11 to 27 months (mean, 21 months). One lenticule was removed because the epithelium did not heal. Peripheral interface opacities occurred in three patients.

Adolescent↗
PubMed1989

Amyloidosis of corneal stroma in patients with trachoma. A clinicopathologic study of 62 cases.

Sixty-two cases of corneal amyloidosis were studied. The median age of the 48 men and 14 women was 66 years. The patients had bilateral, diffuse corneal opacity extending to the limbus and severe visual impairment. The corneal condition was not familial. Advanced stages of trachoma were present in all individuals. Climatic droplet keratopathy (CDK) was also observed clinically in 19 patients. Histopathologically, the Congo red-positive, birefringent and dichroic amyloid deposits in the stroma were similar to that of lattice corneal dystrophy. Bowman's membrane was mostly absent, and peculiar microcystoid degeneration of the stroma was noted. Electron microscopic studies not only confirmed the diagnosis of amyloid but also showed a more diffuse amyloid pattern than did light microscopy. Trachoma is probably the cause of this corneal degeneration with secondary amyloidosis. The environmental conditions associated with CDK may be contributing factors in some cases.

Adult↗
PubMed1986

Observations on the microvascular repair process after confluent argon laser photocoagulation.

We observed the repair process of the choriocapillaris after confluent argon laser retinal photocoagulation in the domestic cat with a plastic injection-corrosion technique coupled with scanning electron microscopy and transmission electron microscopy. Confluent photocoagulation was applied to the area of the retinal tapetum, creating two kinds of lesions: one consisted of five confluent burns and the other of 20 confluent burns. Specimens were prepared at 1, 30, and 60 days. Occlusion of the choriocapillaris was noted regardless of the length of time after photocoagulation. The only sign of repair was noted at 60 days when the choriocapillaris located at the edge of the lesion showed a uniform rearrangement. Transmission electron microscopy revealed severe damage to the endothelial cells, with lack of cell activation and permanent capillary closure in the vessels of the lesion proper.

Animals↗
PubMed1984

Choroidal microvascular repair after argon laser photocoagulation. Ultrastructural observations.

Acute laser injury to the tapetum of the feline retina produces thrombosis of the choriocapillaris. Early changes are characterized by the appearance of platelet-fibrin thrombi within capillary loops and disruption of endothelial integrity. By 4 days, thrombi have disappeared, and the endothelium shows regenerative changes. No endothelial cell mitotic activity is seen. The endothelial cytoplasm becomes plump, and there is a loss of the fenestrations adjacent to Bruch's membrane. By 10-20 days, the capillary structure shows gradual restoration. At 30 days, endothelial cell fenestrae are clearly evident adjacent to Bruch's membrane. The reparative process in this model appears to evolve as a result of thrombolysis and endothelial cell activation.

Animals↗
PubMed1982

Choroidal microvascular repair after argon laser photocoagulation.

We studied the repair process of the choriocapillaris after argon laser retinal photocoagulation in the domestic cat with a plastic injection-corrosion technique and scanning electron microscopy. Retinal scatter photocoagulation was applied to the tapetum at threshold-, moderate-, and high-intensity levels and specimens prepared one, ten, and 30 days later. At 24 hours after photocoagulation, obstruction of the choriocapillaris was always present regardless of the power used. In lesions produced by higher-intensity energy levels, choriocapillaris defects had larger diameters and larger vessels were affected more severely. At ten days, there were early signs of choriocapillaris repair. At 30 days, choriocapillaris occupied almost the entire area of the defect, although the normal lobular architecture was not present.

Animals↗
PubMed1981

Angioarchitecture of the ciliary artery circulation of the posterior pole.

Morphologic findings on scanning electron microscopy of vascular cast of the posterior pole in primates are presented. The prelaminar region of the optic disc received the majority of its blood supply from the short posterior ciliary arteries, mainly from direct branches arising from peripapillary arterioles surrounding the optic nerve but also from indirect branches from the peripapillary choroid. The capillaries from this prelaminar region drained directly into the central retinal vein. The peripapillary choriocapillaris was a single layer of anastomosing capillaries supplied by precapillary choroidal arterioles. The peripapillary choriocapillaris was not seen to contribute to the vascular supply of the optic disc. Our results are in general agreement with those of previous scanning electron microscopy studies of the vascular supply of the distal part of the optic nerve.

Animals↗
PubMed1980

Ocular microcirculation. Scanning electron microscopic study.

A simple vascular casting technique utilizing a low-viscosity plastic was used to study the three-dimensional ocular microcirculation of the cat eye. Vascular arrangements in different anatomic areas of the eye, i.e., iris, ciliary body, retina, optic nerve, and choroid, were clearly elucidated by scanning electron microscopy. This modified technique is described in detail, and scanning electron micrographs are presented to illustrate the reliable results.

Animals↗