Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The details of our previously described theory of how the endothelium controls corneal hydration in the absence of the epithelium are provided. A central postulate is that the endothelium can produce across its limiting plasma membranes an osmotic gradient that reduces stromal swelling pressure so that it does not exceed intraocular pressure during thinning of a swollen cornea.
 ...
PMID:A theory of endothelial control of corneal hydration. 14 86

Theophylline (1 mM) produced a net transport of Na and Cl from aqueous humor to tears (.02-.04 mumol/cm2 h) in the isolated rabbit cornea denuded of endothlium and in the presence of normal resting potential (25-35 mV). The active transport of Na (tears to aqueous) and of Cl (aqueous to tears), estimated with the Goldman constant-field equations, was confirmed. A 10 degrees C rise in temperature produced changes close to those predicted for passive processes in both unidirectional fluxes of Na and in the tears-to-aqueous flux of Cl, but not for the aqueous-to-tears flux of Cl. Theophylline treatment doubled Cl permeability but did not significantly affect Na or urea permeability, suggestingspecificity of affect. In separate experiments it was shown that stromal thinning occurred in previously swollen corneas when the endothelium was blocked by silicone oil and the epithelium was treated with theophylline. These findings provide further support for the argument that the mammalian epithelium could have an active role in the regulation of corneal thickness in situ.
 ...
PMID:Transport of Na, Cl, and water by the rabbit corneal epithelium at resting potential. 16 32

A family of ten individuals aged 18 months to 75 years had biomicroscopic findings consisting of large, amorphous, sheet-like opacifications of the posterior stroma and Descemet's membrane, and alterations of the endothelium. A uniform thinning of the cornea was present. These findings do not conform to previously described corneal dystrophies. The condition appears minimally progressive and the three-generation pedigree indicated an autosomal-dominant inheritance pattern.
 ...
PMID:Posterior amorphous corneal dystrophy. 30 56

In the single individual the central corneal thickness (CCT) shows only small variations. Therefore CCT has been studied in a number of corneal diseases in order to investigate if this dimension might contribute to the diagnosis or to the understanding of the pathogenesis. Normal CCT was found in hereditary dystrophies with the exception of the macular dystrophy of Groenouw (type II), which showed a significantly reduced thickness. Reduced CCT was found in chronic degenerations of leutic, tuberculous or indefinite nature. Marginal degenerations of Fuchs-Terrien type also showed reduced CCT. The possible role of abiotrophic processes in this corneal thinning is dicussed. Endothelial dysfunction is indicated by increased CCT. This occurs in bullous keratopathy and in many acute disorders. Vascularisation of the cornea does not preclude the occurrence of normal or even reduced thickness.
 ...
PMID:Central thickness in corneal disorders. 30 91

The clinical and pathologic findings of a case of congenital bilateral, peripheral corneal leukoma associated with iris coloboma and anterior subluxation of the lens are reported. The changes in the region of keratolenticular apposition include partial absence of Bowman's membrane, stromal vascularization and thinning with large-diameter collagen fibrils, and absence of Descemet's membrane and endothelium. The authors postulate that dysembryogenesis of the tertiary vitreous, with iris coloboma, resulted in apposition of the lens to cornea during the second and third month of gestation and that this apposition resulted in the observed peripheral corneal abnormalities.
 ...
PMID:Peripheral Peters' anomaly: a histopathologic case report. 31 Aug 74

Pellucid marginal degeneration of the cornea is a bilateral, clear, inferior, peripheral corneal-thinning disorder. Protrusion of the cornea occurs above a band of thinning, which is located 1 to 2 mm from the limbus and measures 1 to 2 mm in width. American ophthalmologists are generally not familiar with the condition because most of the literature concerning pellucid degeneration is European. Four cases are described. This condition is differentiated from other noninflammatory cornel-thinning disorders such as keratoconus, keratoglobus, keratotorus, and posterior keratoconus. It is also differentiated from peripheral corneal disorders associated with inflammation such as Terrien's peripheral corneal degeneration, Mooren's ulcers, and ulcers from connective tissue disease.
 ...
PMID:Pellucid marginal corneal degeneration. 35 10

A 15-year-old girl with familial dysautonomia had acute corneal ulcerations while on a respiratory during a dysautonomic crisis. Within 18 days she developed irritating corneal ring calcifications. Subsequent corneal perforation in the left eye was treated successfully with a lamellar graft, followed later by a penetrating graft in the right eye under local anesthesia. Four days postoperatively, the patient died during a vomiting crisis. Neuropathologic studies showed marked cell reduction in the superior cervical and trigeminal ganglia, but slight in the ciliary. The foveas appeared immature and macular ganglion cells were mildly reduced. The corneal button and lamellar grafted cornea had severe thinning and superficial calcification. Keratoplasty in familial dysautonomia is considered hazardous because of the continual threat of vomiting crises, but with sufficient care may be worthwhile for corneal perforation or advanced corneal scarring.
 ...
PMID:Corneal transplantation in familial dysautonomia. 39 Oct 49

Keratoconus is a disease that results in thinning and ectasia of the central cornea. Cultures of corneal stromal cells from patients with keratoconus were established and the synthesis of glycosaminoglycans compared with the synthesis of glycosaminoglycans by normal human corneal stromal cells in culture. Keratoconus and normal control cell cultures were incubated with sodium [(35)S]sulfate and [(3)H]glucosamine for 4 h. After incubation, the labeled glycosaminoglycans were isolated from the medium fractions and cells. Keratoconus and normal control cultures synthesized similar amounts of sulfated glycosaminoglycans independent of the age of donors and(or) the number of subcultures. In contrast to normal control cultures, most of the newly synthesized glycosaminoglycans produced by keratoconus cells were found in the growth medium and much less were in the cell layer. Treatment with glycosaminoglycan-degrading enzymes followed by paper chromatography showed that keratoconus cells, as normal control cells, produced hyaluronic acid and various sulfated glycosaminoglycans. The production of cell layer-related heparan sulfate was markedly reduced in keratoconus cultures. Because heparan sulfate has been shown to be associated with cell surfaces, the decreased heparan sulfate content could reflect changes at this location.
 ...
PMID:The synthesis of glycosaminoglycans by cultures of corneal stromal cells from patients with keratoconus. 43 19

Posterior keratoconus is a rare corneal disorder characterized by a total or localized noninflammatory thinning of the cornea. In front of a conical protrusion of the posterior corneal curvature, there is a thinned stroma and nonprotruding anterior surface. A corneal button from a patient with bilateral posterior keratoconus was studied by light and electron microscopy. Descemet's membrane, particularly in the area of stromal thinning, demonstrated abnormal anterior banding, a multilaminar configuration, and localized posterior excrescences. These alterations suggest an early pathogenetic mechanism, which probably originated prior to the fifth or sixth month of gestation.
 ...
PMID:Posterior keratoconus. 69 25

After intralamellar implantation of Teflon-membranes (4,0 mm/0,125 mm) without perforation there is an epithelial thinning over the membrane after 6 days, after 15 days metachromatical staining over the membrane is reduced, after 21 days there is a central defect of the cornea over the membrane and after 28 days the membrane is pushed out of the cornea. When Teflon-membranes (4,0 mm/0,125 mm) are inserted with one central perforation or three perforations of 1 mm epithelial thinning, reduced metachromasia and defects of the cornea over the membrane occurred later. But even these membranes are pushed out of the cornea after some time. The results with thinner Teflon-membranes (4.0 mm/0.05 mm) do not show much difference. The reason for the reduced metachromasia of the cornea over Teflon-membranes seems to be a lower rate of syntheses of glycosaminoglycanes because of the reduced glucose content in this part of the cornea. As the experiments with the intracorneal control-pockets without implantation of a Teflon-membrane show, wound-healing is not responsible for the reduced metachromasia over the membrane.
 ...
PMID:[Corneal changes after implantation of intralamellar teflon-membranes (author's transl)]. 78 46


1 2 3 4 5 6 7 8 9 10 Next >>