Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The content and localization of fibronectin, an extracellular glycoprotein, in the serial sections of lenses of normal human donors and cataractous patients of different ages were determined by the indirect immunoperoxidase staining technique. This was followed by the evaluation with quantitative morphometric analysis. It was shown that fibronectin was present in the area of cell contacts as single deposits of faint orange-brown stained material in the lens samples of young donors. The fibronectin level was raised in lens sections from aged donors. Its accumulation was detected mostly within the spaces of the lens fiber cells. At different stages of cataractogenesis a dramatic decrease of the fibronectin content was detected in the lens sections obtained from patients of different ages. A new linear spectrophotometric technique was developed for evaluation of the lens transparency, to correlate the lens opacity with corresponding histological data obtained from the immunostaining technique. Morphological studies performed further suggested that the lens fiber cell plasma membrane structures were deteriorated. This was observed as changes of fibronectin staining in the lens sections at different periods of human ageing and cataract development. It is concluded that a decrease of fibronectin staining in the human lens is an indication for the structural damage of the lens fiber cell plasma membranes during ageing and cataractogenesis.
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PMID:Changes in fibronectin staining in the human lens during ageing and cataractogenesis. 200 27

Increased glycosylation of various proteins in diabetic patients has been reported by many authors. In the present study, the extent of non-enzymatic glycosylation in diabetic patients with or without chronic complications was investigated. Eighty-five diabetic patients were studied, 20 were without any clinical evidence of chronic complications while the remainder were suffering from cataract (n = 18), retinopathy (n = 16), peripheral neuropathy (n = 16) and cardiovascular complications like angina pectoris, myocardial infarction and hypertension (n = 15). All patients were selected on clinical grounds. Fifteen apparently healthy subjects of similar age and weight were studied as control subjects. Fasting plasma glucose was increased in all diabetic patients and correlated significantly with glycosylated hemoglobin, glycosylated plasma protein and serum fructosamine concentrations. There was no significant difference between diabetic patients with or without chronic complications in the levels of fasting plasma glucose, glycosylated plasma proteins, glycosylated hemoglobin, serum fructosamine, mucoprotein, hexosamine, sialic acid and fucose. Alpha-2 globulin fraction was increased in both uncomplicated and complicated diabetic patients and albumin was found to be decreased in patients with cataract, peripheral neuropathy and cardiovascular diseases. Alpha-1 and beta globulins were significantly decreased in patients with cardiovascular diseases and retinopathy respectively while gamma globulin was increased in retinopathy patients. In uncomplicated diabetic patients alpha-1 glycoprotein was decreased and gamma glycoprotein was increased. In diabetic patients with retinopathy, alpha-1 glycoprotein was elevated significantly while beta glycoprotein was decreased.
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PMID:Changes in glycosylated proteins in long-term complications of diabetes mellitus. 216 68

Quantitative analyses by crossed immunoelectrophoresis were carried out on 31 eyes of 26 cataract patients, age 4-80 years, to detect age changes in the human aqueous humor especially in the following aqueous humor proteins: prealbumin, albumin, alpha 1-acid glycoprotein and transferrin. There was a significant correlation between age and concentration of each of the 4 proteins. The results reported in this paper may be due to senile alteration of the pathway that serum proteins follow from the leaky vessels of the ciliary body to the anterior chamber and/or to a decrease of the aqueous flow rate with advancing age. The relationship between the ages and the aqueous humor protein levels established in this study can be utilized as controls in studying the aqueous humor proteins in uveitis and other ocular diseases.
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PMID:Increase of aqueous humor proteins with aging. 318 47

The concentration of the high molecular glycoprotein fibronectin (FN) was measured by an enzyme-linked immunoadsorbent technique (ELISA) in tears of 25 patients before and after cataract extraction. Both native and degraded FN was measured. The median concentration of FN in tears before surgery was 0.28 mg/l (range: 0.1-3.8 mg/l) and 0.18 mg/l (range: 0.1-1.95 mg/l for degraded and native FN, respectively. The time course of the median values of both types of FN during the post-operative observation period described a biphasic curve with peaks at the second and fifth day following operation. On the twelfth day the concentration of degraded and native FN had almost reached pre-operative levels. The variation in the post-operative FN concentration proved statistically significant. The biological significance of the changes in FN level in the post-operative period is not obvious; the first peak may be explained by a spill-over from plasma, and the second peak may reflect FN production from fibroblasts in the granulation tissue of the corneoscleral cicatrix.
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PMID:Fibronectin in tears following surgical trauma to the eye. 387 63

The partial purification of (Na+ + K+)-ATPase from pig lens has been achieved by treatment with deoxycholate followed by density gradient centrifugation. The specific activity of the final preparation, ranging from 300 to 500 nmol/h per mg protein, is increased approx. 100-fold compared to the homogenate. A parallel increase in rho-nitrophenylphosphatase activity is also observed. Sodium dodecyl sulfate (SDS) gel electrophoresis reveals six major protein bands, one of which is the 93 kDa alpha subunit of (Na+ + K+)-ATPase which can be phosphorylated by reaction with [gamma-32P]ATP. A second band contains a glycoprotein which displays an apparent molecular weight of 51000 and thus appears to be the beta subunit of the enzyme. The enzyme is sensitive to ouabain with the I50 for (Na+ + K+)-ATPase and rho-nitrophenylphosphatase inhibition being 1.2 and 1.3 microM, respectively. Several agents which inhibit (Na+ + K+)-ATPase from other tissues such as oligomycin, Ca2+, vanadate, N-ethylmaleimide, rho-chloromercuribenzenesulfonic acid (PCMBS) and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) also inhibit the lens enzyme. Monovalent cations other than K+ are partially effective in activating the (Na+ + K+)-ATPase and rho-nitrophenylphosphatase activities. The K+ congeners were relatively more effective in supporting (Na+ + K+)-ATPase compared to rho-nitrophenylphosphatase activity. Other kinetic properties of the lens enzyme are also comparable to those of the enzyme from other tissues. Utilizing the partially purified membrane bound enzyme, discontinuities in Arrhenius plots of (Na+ + K+)-ATPase activity, rho-nitrophenylphosphatase activity and fluorescence polarization of the fluidity probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), are observed near the physiological temperature of lens. The possible significance of these observations for the mechanism of cataract formation are discussed.
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PMID:Characterization of partially purified (Na+ + K+)-ATPase from porcine lens. 629 83

The Philly mouse is a new model for genetic cataracts, in which there is an apparent defect in lens membrane permeability. This abnormality results in electrolyte imbalance and lens hydration, typical of an osmotic cataract. Since membrane glycoproteins are believed to be involved in transport processes, we have studied the changes in these polypeptides in the Philly mouse lens during cataract development and compared them with those in the control Swiss-Webster mouse. The membrane glycoproteins were labeled by treatment with galactose oxidase and tritiated borohydride. Radioactivity was found to be incorporated into six glycoproteins of approximate molecular weights of 128 k, 103 k, 82 k, 71 k, 35 k, and 22 k daltons. The 35 k polypeptide is the major glycoprotein in the mouse lens membrane and shows increased incorporation of the tritium label with progression of the cataract. In contrast to the murine lens, the 35 k peptide could not be detected in rabbit lens membranes. Other changes observed in glycoproteins of the Philly mouse lens during cataract development were a loss of the 103 k and 71 k polypeptides and a corresponding increase in the 66 k polypeptide. These changes in glycoproteins may be related to the permeability changes and cataract development in the Philly mouse lens.
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PMID:Membrane glycoproteins of Philly mouse lens. 688 17

The lens has a very high content of UDP sugars. These are required for glycoprotein and proteoglycan synthesis, as components of fiber cell membranes and the capsule. In diabetes, changes in these sugar nucleotides are related to pathological changes in the basement membranes of cells from non-insulin-requiring tissues. We have investigated whether this is the case in the lens in diabetes and we report here that UDP-sugar levels are, in contrast to the norm in other non-insulin-requiring tissues, decreased at 2 and 4 weeks of diabetes. This is despite an elevation in the precursors of their formation, both of the pyrimidine (PPRibP) and carbohydrate (glucose, glucose 6-phosphate) components. Also reported here is the observation that lens pyrimidine biosynthesis occurs primarily by the de novo route, and that orotate phosphoribosyltransferase and orotidine-5'-phosphate decarboxylase are unchanged in diabetes. We have measured the energy charge of the adenine and uridine nucleotide pools and report both to be compromised under the diabetic condition. The fall in ATP provision is proposed to be responsible for the fall in UTP and hence leads to the recorded decrease in the UDP sugars. These changes are discussed in relation to the change in capsular and fiber cell composition and the functional significance of this in cataract formation.
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PMID:Changes in uridine nucleotides and uridine nucleotide sugars in diabetic rat lens: implications in membrane glycoprotein formation. 812 94

To clarify the participation of the lens epithelial cells in the postoperative fibrin formation in cataract surgery, the generation of procoagulant activity (PCA) by cultured rabbit lens epithelial (RLE) cells was investigated. PCA was detected in the homogenates of RLE cells cultured for three hours. PCA was increased approximately three- to four-fold by lipopolysaccharide (LPS) stimulation in a dose dependent manner. Treatment of the RLE cells with Concanavalin A resulted in a decrease of PCA. PCA of the RLE cells was not observed in Factor VII deficient plasma, as a standard tissue factor (TF). Parallelism was recognized between the dose response regression lines for the PCA in the RLE cells and standard TF. These results suggest that the PCA in the RLE cells is similar to TF, which has glycoprotein as an active site and requires coagulation factor VII. Some arachidonic acid metabolic cascade inhibitors which show an inhibitory effect for fibrin formation in vivo reduced the generation of PCA by the RLE cells in vitro. The activation of arachidonic acid cascade followed by the generation of PCA in the RLE cells may participate in postoperative fibrin formation.
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PMID:[Participation of procoagulant activity of cultured rabbit lens epithelial cells in fibrin formation]. 835 77

Pseudoexfoliation (PEX) syndrome is a common, but little known, systemic degenerative condition manifest by the extracellular deposition of a distinctive fibrillar material (PEX material) in various organs. In the eye, PEX material is characteristically found on the surfaces of structures that line the anterior and posterior chambers, and it is associated with cataract and glaucoma. Although PEX material contains several elements normally present in basement membranes, its precise composition remains obscure. Because the glycoprotein thrombospondin 1 (TSP1) can be shown in some basement membranes, we attempted to define its involvement in the composition of PEX material by immunohistochemical analysis of ocular tissues from patients with PEX syndrome. Although we were unable to detect TSP1 in PEX material, we were surprised to find that iris and corneal stromal fibroblasts expressed TSP1. In age-matched normal eyes, iris and corneal fibroblasts did not contain demonstrable TSP1. These observations indicate that TSP1 is not a significant component of PEX material but suggest that, in PEX syndrome, stromal fibroblasts remote from the principal sites of PEX material deposition are altered at the molecular level. The findings add evidence to the theory that PEX syndrome represents a disorder of connective tissue metabolism and intimate that the syndrome involves anomalous production of proteins other than those found in PEX material.
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PMID:Unexpected expression of thrombospondin 1 by corneal and iris fibroblasts in the pseudoexfoliation syndrome. 895 94

SPARC (secreted protein acidic and rich in cysteine, also known as osteonectin/BM40) is a secreted Ca2+-binding glycoprotein that interacts with a range of extracellular matrix molecules, including collagen IV. It is widely expressed during embryogenesis, and in vitro studies have suggested roles in the regulation of cell adhesion and proliferation, and in the modulation of cytokine activity. In order to analyse the function of this protein in vivo, the endogenous Sparc locus was disrupted by homologous recombination in murine embryonic stem cells. SPARC-deficient mice (Sparctm1Cam) appear normal and fertile until around 6 months of age, when they develop severe eye pathology characterized by cataract formation and rupture of the lens capsule. The first sign of lens pathology occurs in the equatorial bow region where vacuoles gradually form within differentiating epithelial cells and fibre cells. The lens capsule, however, shows no qualitative changes in the major basal lamina proteins laminin, collagen IV, perlecan or entactin. These mice are an excellent resource for further studies on how SPARC affects cell behaviour in vivo.
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PMID:Mice deficient for the secreted glycoprotein SPARC/osteonectin/BM40 develop normally but show severe age-onset cataract formation and disruption of the lens. 952 10


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