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Biomedical subjects

G K Klintworth

Publications and source records attributed to G K Klintworth.

At least 19 recordsLinked to original sources
PubMed1992

Transgenic mice expressing a constitutively active retinoic acid receptor in the lens exhibit ocular defects.

Retinoic acid receptors (RARs) modulate gene expression following association with retinoic acid (RA). In transient transfection, an RAR alpha-beta-galactosidase fusion protein (RAR-LacZ) was able to transactivate expression in the absence of RA. When expressed in the ocular lens of transgenic mice, this constitutively active RAR-LacZ fusion gene resulted in founder and progeny animals that exhibited cataracts and microphthalmia, both being characteristics of retinoid-induced teratogenesis. The transgenic phenotypes indicate that retinoid teratogenesis can be mimicked by expression of a constitutively active RAR-LacZ fusion protein in retinoid-sensitive tissues.

Animals↗
PubMed1979

Enlargement of a histologically documented choroidal nevus.

An elevated pigmented mass of the choroid remained stable for 6 1/2 years and then was documented photographically to have increased in size. The tumor stained on fluorescein angiography, produced a visual field defect, and differentially took up radioactive phosphorus. The eye was enucleated and on histologic examination contained a nevus of the choroid. This case shows that enlargement of a choroidal nevus may occur during adulthood, and suggests that despite newer and more sophisticated diagnostic techniques, large nevi and small melanomas of the choroid may be clinically indistinguishable.

Adenoma↗
PubMed1979

Corneal edema in essential iris atrophy.

In a clinical study of the essential iris atrophies, corneal edema occurred in 49 of 90 patients, and a characteristic hammered-silver appearance of the posterior cornea was visible in 54 cases. Intraocular pressure in the eyes with corneal edema ranged from normal to extreme elevation with glaucomatous damage, and lowering the pressure relieved the corneal edema in many cases with penetrating keratoplasty being effective when other measures failed. Electron microscopy of two keratoplasty specimens revealed extremely few, distinctly abnormal cells lining a collagenous layer posterior to Descemet's membrane.

Adolescent↗
PubMed1979

Morphologic observations on experimental corneal vascularization in the rat.

The morphologic evolution of the early events of corneal vascularization in the rat cornea induced by silver nitrate cautery were followed by light and electron microscopy. An initial acute inflammatory response occurred within the first 6 hours after cautery as evidenced by vascular dilation, diapedesis of leukocytes, and an increased vascular permeability, as manifested by distended lymphatics and the presence of extravascular fibrin. At 24 hours after injury, the hypertrophy and the prominence of nucleoli and the presence of abundant polyribosomes were the initial suggestion that vascular endothelial cells and pericytes had entered the mitotic cycle. Nine hours later, at 33 hours after cautery, the first new vessels were observed as sprouts from the capillary arcade and postcapillary venules. The experiments reemphasize the association of acute inflammation and corneal vascularization in this model and underscore the early occurrence of vascular endothelial cell replication.

Animals↗
PubMed1979

Acridine orange particles in cultured fibroblasts. A comparative study of macular corneal dystrophy, systemic mucopolysaccharidoses types I-H and II, and normal controls.

Vital staining with the fluorescent dye, acridine orange, was evaluated as a means of detecting abnormalities of lysosomes in cultivated fibroblasts of patients with macular corneal dystrophy and mucopolysaccharidoses types I-H (Hurler's syndrome) and type II (Hunter's syndrome). Multiple cultures were compared with normal fibroblasts using a "double-masked" design to exclude observer bias. Cells of patients with the mucopolysaccharidoses were easily and accurately separated from other fibroblasts. Contrary to a recent report, corneal fibroblasts of patients with macular corneal dystrophy were indistinguishable from control cells.

Acridine Orange↗
PubMed1978

Sarcoidosis and its ophthalmic manifestations.

Of 532 cases of sarcoidosis in the southeastern United States, ocular manifestations were a prominent feature of the disease in 202 (38%) of the patients. Approximately one fifth of them sought medical attention because of ocular complaints. This was the second most frequent clinical manifestation, exceeded only by pulmonary symptoms. When ocular segment structures were affected, the anterior segment was involved in 171 (84.7%) of cases. Chronic granulomatous uveitis was the most common abnormality in 106 cases (52.5%). Posterior segment disease occurred in 51 (25.3%) of cases, usually in the form of chorioretinitis or preiphlebitis; it was sometimes the sole manifestation of ocular sarcoidosis, but usually accompanied abnormalities in the anterior part of the eye. The incidence of central nervous system sarcoidosis was increased when posterior segment involvement was observed. Orbital and adnexal structures, primarily lacrimal gland, were affected in 53 (27.7%) of cases.

Adolescent↗
PubMed1978

Analysis of corneal crystalline deposits in multiple myeloma.

A 46-year old woman and a 59-year-old man had corneal crystals, multiple myeloma, and IgG kappa hypergammaglobulinemia. In one case, crystalline deposits were also present in the lens. In both patients there was a marked decrease in the amount of crystals during chemotherapy. The crystals within the cornea of one case were identified by light and electron microscopy in material obtained during a lamellar keratoplasty. The crystalline deposits were located only in the corneal epithelium, and their regular repeating internal arrangement was confirmed by monochromatic optical diffraction of electron micrographs of sections through them. By immunofluorescent and immunoperoxidase techniques, the crystals reacted positively for immunoglobulin and particularly IgG kappa chains.

Cornea↗
PubMed1978

Radiographic abnormalities in eyes with retinoblastoma and other disorders.

The importance of radiographic examinations of pathological ocular material is stressed. Characteristic ocular radiodensities are observed with retinoblastomas, calcified cataracts, senile scleral plaques, intraocular ossification, and a variety of radiodense foreign bodies. Radiographs supplement other techniques for the documentation of ocular abnormalities and in certain instances may be the ideal method. They also permit the precise localisation of radiodense foreign bodies that need to be removed prior to the processing of tissue for microscopic examination. In certain situations valuable data can be obtained by x-ray examinations of embedded material. Retinoblastomas have an extremely high incidence of radiodensities with a characteristics appearance. This finding stresses the clinical importance of utilising and developing clinically applicable techniques for the detection of calcification in patients with suspected retinoblastomas.

Calcinosis↗
PubMed1977

Calcification of basal ganglia and cerebellar roof nuclei in mentally defective patient with hidrotic ectodermal dysplasia. Analysis of intracranial concretions by electon microprobe.

This report describes, for the first time, an analysis by electron microprobe of concretions in the brain of an individual with striopallidodentate calcification. We also report the unique association of this intracranial syndrome with hidrotic ectodermal dysplasia. An institutionalized male with impaired intellectual function and hidrotic ectodermal dysplasia was known since the age of 3 years to have bilateral radiopaque densities in the region of the basal ganglia on skull roentgenogram. He died at age 29 in congestive heart failure from rheumatic pancarditis. At autopsy, concretions were identified in globus pallidus, caudate nuclei, thalamus, and dentate nuclei. Mineral deposits within the brain, analyzed by energy dispersive x-ray microanalysis, consisted predominately of calcium and phosphorus. Trace amounts of magnesium, iron, and silicon also were detected.

Adult↗
PubMed1977

Macular corneal dystrophy. Studies of sulfated glycosaminoglycans in corneal explant and confluent stromal cell cultures.

The inherited disorder macular corneal dystrophy (MCD), a localized corneal mucopolysaccharidosis, is currently thought to result from an inability to catabolize corneal keratan sulfate (keratan sulfate 1). As studies on isolated cells have provided insight into metabolic abnormalities in other inherited disorders, we investigated cultured corneal fibroblasts from 4 patients with MCD from several standpoints. Lines of corneal fibroblasts with MCD could not be distinguished from controls with cytochemical methods known to stain the naturally occurring accumulations. In contrast to cultured fibroblasts from patients with mucopolysaccharidoses Type I-H (Hurler syndrome) and Type II (Hunter syndrome), corneal fibroblasts from patients with MCD did not accumulate abnormal quantities of (35)S-sulfate-labeled glycosaminoglycans, but like normal corneal and cutaneous fibroblasts reached a state of equilibrium within 2 days. Also, the rate at which sulfated glycosaminoglycans were removed from cultured corneal fibroblasts in MCD by secretion and degradation more closely resembled that of normal cells than those with the systemic mucopolysaccharidoses. The secretion of sulfated glycosaminoglycans into the nutrient medium by corneal fibroblasts from patients with MCD occurred at a linear rate comparable to that of other cells studied. The aforementioned data, nonetheless, remain consistent with the hypothesis that MCD is an inherited disorder of keratan sulfate I (corneal keratan sulfate) catabolism, as isolated corneal fibroblasts in contrast to corneal explants synthesize little or no keratan sulfate in culture. In view of the latter, we also compared the profile of (35)S-labeled glycosaminoglycans produced by a corneal explant from a patient with MCD with that normally synthesized by human corneal explants. The latter synthesized and secreted a population of (35)S-sulfate-labeled glycosaminoglycans with properties of keratan sulfate. Considerably less material with these attributes was identified with the same analytic techniques in the cornea with MCD or in its surrounding medium after the abnormal cornea had been incubated under identical conditions. In addition to manifesting an impaired synthesis of corneal keratan sulfate-like material, the cornea with MCD produced a greater percentage of chondroitin-6-sulfate than normal. These findings suggest that the synthesis of corneal keratan sulfate and other glycosaminoglycans may be altered in MCD.

Adult↗
PubMed1977

Calcification of soft contact lenses in patient with dry eye and elevated calcium concentration in tears.

Following radiotherapy for an extensive intraepithelial carcinoma of the conjunctiva and eyelid, a patient developed opacification of soft contact lenses used on the same side. Calcilm was demonstrated within the contact lenses by cytochemical methods and by energy-dispersive x-ray microanalysis. The phenomenon was associated with unilateral tear insufficiency and an elevated tear calcium level as determined by atomic absorption spectrophotometry.

Calcium↗
PubMed1977

The contribution of morphology to our understanding of the pathogenesis of experimentally produced corneal vascularization.

In many disorders of the cornea, blood vessels invade this normally avascular tissue. Several theories have been proposed to explain the pathogenesis of corneal vascularization. Since none had received general acceptance, experimental studies of the phenomenon were begun several years ago in hamster cheek pouch chambers. These investigations which employed sequential morphologic studies during the process of corneal vascularization gave rise to a new hypothesis, namely, that corneal vascularization is usually a manifestation of the inflammatory response and mediated by leukocytes. This report briefly reviews the evolution, evidence, and current status of this theory.

Animals↗
PubMed1976

An unusually large human eye with abnormal scleral collagen.

Severe progressive ocular enlargement of late onset accompanying chronic uveitis and secondary glaucoma occurred in an 18-year-old man. Electron microscopy of the thin sclera from the unusually large eye (40x40x37 mm) disclosed collagen fibrils with mean widths that exceeded that of controls, but that were within the range of the fibril size typically present in the outer sclera. Thinner fibrils that normally occur particularly within the inner sclera were conspicuously absent. Morphologic observations on corneal and cutaneous collagen from the patient were unremarkable. No abnormality was detected on chemical analysis of cutaneous collagen. The abnormal morphologic pattern of the scleral collagen is interpreted as a probable arrest in scleral collagen synthesis.

Adolescent↗
PubMed1976

Pigmented squamous cell carcinoma of cornea and conjunctiva: A light microscopic, histochemical, and ultrastructural study.

A light microscopic, histochemical, and ultrastructural study was performed on tissue obtained from a pigmented squamous cell carcinoma of the cornea and conjunctiva. To the best of our knowledge this is the first time that one of these rare pigmented squamous cell carcinomas of the ocular mucous membrane has been described in detail. The occurrence of this neoplasm, which needs to be differentiated from other pigmented lesions, and particularly epibulbar melanomas, underscores the fact that all pigmented tumors are not melanomas. The study revealed that melanin granules, which accounted for the pigmentation of the neoplasm, were present in variable numbers in neoplastic squamous cells, Langerhans cells, macrophages, and stellate cells identified as melanocytes with mature melanosomes. Premelanosomes were not observed in any of these cells types. Current concepts concerning the common association of Langerhans cells with their characteristic intracytoplasmic "Birbeck granules" and melanocytes are discussed.

Carcinoma, Squamous Cell↗
PubMed1976

An evaluation of the role of leukocytes in the pathogenesis of experimentally induced corneal vascularization. III. Studies related to the vasoproliferative capability of polymorphonuclear leukocytes and lymphocytes.

Studies in the past have suggested that leukocytes are a prerequisite to corneal vascularization. To test this hypothesis further, experiments were conducted to determine whether the intracorneal instillation of polymorphonuclear leukocytes, lymphocytes, or components of leukocytes would induce a corneal vascular ingrowth. These cells or cellular fractions were injected intracorneally into Fisher albino rats whose circulating leukocytes had been depleted by total body x-irradiation. Polymorphonuclear leukocytes isolated from glycogen-induced peritoneal exudates caused a corneal vascular invasion, but lymphocytes obtained from thymus, spleen, and lymph nodes failed to do so. To learn whether an extractable factor could be isolated from polymorphonuclear leukocytes these cells were suspended in isotonic saline, ultrasonified and then centrifuged at 101,952g for 1 hour. Aliquots of the resulting sediment and supernatant were injected intracorneally into rats with radiation-induced leukopenia. The nonsedimentable supernatant caused corneal vascularization, but the sediment did not provoke the phenomenon. These studies not only provide further support for the hypothesis that leukocytes initiate corneal vascularization, possibly by the release of one or more heat labile chemical mediators, but directly implicate the polymorphonuclear leukocyte in this process.

Animals↗