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

A dominant cataract mutation was detected recently among the offspring of x-ray-irradiated male mice. The mutation, which causes total lens opacity, has provisionally been designated by the gene symbol Cat-2t. In the lenses of heterozygous and homozygous Cat-2t mutants, the epithelial and fiber cells were swollen and the lens capsule was ruptured. The histologic analysis demonstrated a complete destruction of the cellular organization of the lens, which might be caused by its altered developmental processes. The data derived from biochemical investigations indicate that biochemistry of the cataractous Cat-2t lenses is affected: the osmotic state as indicated by the increased water content and increased Na(+)-K(+)-adenosinetriphosphatase (ATPase) activity; the energy state as indicated by the decreased adenosine triphosphate (ATP) concentration; and the redox state as indicated by the enhanced content of oxidized glutathione. Additionally, the lenticular protein composition is altered because of the presence of vimentin in the water-soluble fraction. This cannot be explained by the enhanced crosslinking activity of transglutaminase. The changes of the osmotic, energy, and redox states are considered to be secondary in relation to the altered lenticular development. In contrast, the variations concerning vimentin and transglutaminase might be a biochemical indication of the changed development. Possible similarities to other dominantly expressed murine cataract mutants are discussed.
 ...
PMID:Characterization of Cat-2t, a radiation-induced dominant cataract mutation in mice. 197 59

Development of improved hydrogels for soft intraocular lenses, based on 2-hydroxyethyl methacrylate monomer, requires the use of various other monomers and polymerization additives which have potential ocular toxicity. Three monomers, 2-hydroxyethyl methacrylate, methyl methacrylate, and 2-ethoxyethyl methacrylate, as well as two common inhibitors, hydroquinone and 4-methoxyphenol, were subjected to in vitro cytotoxicity assays as aqueous solutions at different concentrations. A new polymerization initiator, 2,2'-azo-bis-(2,4-dimethyl valeronitrile), was thermally decomposed in water at different concentrations and the products were also assayed for cytotoxicity. Assays were based on incubation with human choroidal fibroblasts. Cell death was evaluated by trypan blue dye exclusion, DNA synthesis inhibition, and lactate dehydrogenase tests. While methyl methacrylate and 2-ethoxyethyl methacrylate were found nontoxic, the other chemicals displayed high cytotoxicity. However, when extracts of synthesized poly(2-hydroxyethyl methacrylate) specimens, differentially treated after polymerization, were subjected to the same assays it was found that toxicity from residual 2-hydroxyethyl methacrylate monomer was lost during steam sterilization and storage in water because of the removal of the monomer through aqueous washing. The lack of toxicity in these specimens suggests that residual contents of inhibitor and initiator are too low to cause toxic effects on choroidal fibroblasts. It is concluded that hydrogels have low cytotoxic effects in vitro.
J Cataract Refract Surg 1991 Mar
PMID:Cytotoxic effects of residual chemicals from polymeric biomaterials for artificial soft intraocular lenses. 204 Sep 72

We found a female cataractous DDD/1-nu/+ mouse and established a hairy mutant strain (DDD/1-Cti/Cti) with 100% incidence of cataract from it by repeating sibmating. Genetic studies demonstrated that a single autosomal semidominant gene controls cataractogenesis. This gene was named Cti. In homozygotes, DDD/1-Cti/Cti, the lenses began to opacify at 14 days of fetal life and were recognized clinically as cataract at 13-14 days of age when the eyes first open. The opacification became more and more intense with age and looked like mature cataract at 28-42 days of age. However, clarification of the opacified lenses commenced at the periphery after 56 days of age and expanded to the inside with time, and only an opaque spot was left at the center at 140 days of age. In heterozygotes, DDD/1-Cti/+, the lenses were recognizable as cataract after 28 days and became like mature cataract around 35 days of age. The opacity began to be lightened at 42 days and the lenses appeared normal at 56 days of age. Both lenses and eyeballs developed in similar courses in DDD/1(-)+/+, -Cti/+ and -Cti/Cti, although slightly retarded in the last. Microphthalmia was not accompanied even in DDD/1-Cti/Cti. The lens water content remained higher during the time when intense lens opacity continued in DDD/1-Cti/Cti and -Cti/+. Background genes appeared to affect the expression of Cti. DDD/1-Cti(-)+ mice may provide a model for researches into clarification of opaque lenses. A discussion concerning the possible allelism of Cti and Cts with Lop was made based on their phenotypic characteristics.
 ...
PMID:[Characterization of dominant hereditary cataract in DDD/1 mice]. 204 67

Phacoemulsification combined with pars plana vitrectomy was performed on seven patients with both cataracts and vitreoretinal disease. Six of the seven had a posterior chamber intraocular lens (PC-IOL) placed in the capsular bag following cataract extraction. Visual acuities ranging from light perception to hand movement preoperatively, postoperatively ranged from hand movement to 20/25. There were no perioperative complications. During an average follow-up of more than 6 months, neovascular glaucoma developed in one patient, and a conjunctival cyst in another. The PC-IOLs were well tolerated. The small limbal incision used in phacoemulsification allows better control during the vitrectomy procedure and ensures a water-tight wound. In addition, with the limbal approach, the posterior lens capsule is maintained, with all the attendant advantages.
 ...
PMID:Phacoemulsification combined with pars plana vitrectomy. 205 80

Congenic hereditary cataract mice, BALB/c-nct/nct, were established by introducing the nct gene from Nakano into BALB/c mice. These mice developed a milder cortical form of cataract which developed sporadically and later in life than in Nakano mice. Combined use of BALB/c and BALB/c-nct/nct mice enables biochemical comparison of normal clear lenses, congenic clear lenses which are destined to be opacified some time later, and opacified lenses in the same genetic and aging statuses. We compared the age-related changes in water content and water-soluble and -insoluble fractions among these three types of lenses. Congenic clear lenses and opaque lenses were more similar to BALB/c normal clear lenses and Nakano opaque ones, respectively, in these parameters. These results suggest, in addition to formation of aggregated crystallins and their accumulation in water-insoluble fractions, that decreased protein synthesis, increased protein degradation and augmented leakage of crystallin might have a significant role in the nct-induced lens opacification.
 ...
PMID:Biochemical evidence for conversion to milder form of hereditary mouse cataract by different genetic background. 206 20

Transplantation of isolated islets is a promising approach in the treatment of diabetes. We have examined the long-term effects on the late complications of islet transplantation in an experimental diabetes model in the rat. Diabetes was induced by streptozotocin (70 mg/kg i.v.) and the rats were treated with either insulin (daily injection of 40 U) or transplantation of 1,000 freshly isolated, hand-picked, islets into the left renal subcapsular space. Both islet transplantation and insulin treatment completely normalized the increased levels of blood glucose, urine volume and water intake that were observed in the diabetic rats. The decreased growth rate of the diabetic rats was almost normalized by both treatment protocols. As for late complications, after 3 months, all untreated diabetic rats had cataract. They also had swelling and vacuolation of renal tubular cells, and, consistent with this, very high levels of urinary beta 2-microglobulin excretion. Both islet transplantation and insulin treatment completely prevented these late complications. Thus, islet transplantation to the renal subcapsular space is in this experimental model as good as insulin treatment in treating the clinical signs of diabetes and in preventing diabetic complications in the eye and kidney.
 ...
PMID:Islet transplantation to the renal subcapsular space improves late complications in streptozotocin-diabetic rats. 207 89

This study deals with the effects of the SH oxidizing agent diamide (diazene dicarboxylic acid bis-(N,N-dimethyl-amide)) on the water-soluble proteins from rabbit lenses. The dialyzed protein extracts were incubated for 0.5-1.5 h with various concentrations of diamide. Alterations in sulphydryl contents, gel filtration and gel electrophoresis profiles of proteins were recorded. The response to 2 mM diamide treatment for 1 h consists of rapid oxidation (up to 40%) of protein-bound sulphydryl groups accompanied by appearance of polypeptides with apparent molecular weights in excess of 68,000. A protein with a molecular weight of 29 kDa was shown to be specially involved in cross-linking. The linkages in the dialyzed water-soluble lens protein fraction induced by diamide may be reduced by GSH (10 mM) treatment of the protein extract. The main target of oxidative insult induced by diamide in the water-soluble proteins of the lens is probably the superficially localized sulphydryl groups of crystallins. Our observations suggest that this oxidative system of proteins may be a useful tool for cataract research.
 ...
PMID:Diamide-induced cross-linking of the lens water-soluble proteins as a model of the early oxidative changes during senile cataract formation. 208 97

When monitoring for drug induced lenticular side effects and/or anti-cataract drug efficacy, it would be advantageous to detect such effects prior to the onset of a cataract. Our MRI technique can detect precataractous changes in the lens water compartments (T2 values) months to years before opacities become manifest. The in vivo human and animal studies correlate well with in vitro NMR pulse relaxation data on such lenses. The MRI technique requires 2-4 minutes per eye and provides excellent pictures of the globe as well as T2 values. These data correlate well with our in vivo lens fluorescence technique thereby providing two parameters capable of evaluating potential drug induced changes in the lens well before the cataract becomes manifest.
 ...
PMID:Biophysical methods to monitor lens aging and pre-cataractous changes in vivo. 210 Jan 62

It has been suggested that sugar cataracts associated with diabetes mellitus result from the accumulation of excess sorbitol within lens fibrils. Swelling of lens fibrils occurs when water moves in to maintain osmotic balance; the excess water causes disruption of fibrils and cataract formation. Other studies have indicated that more than sorbitol-induced osmotic stress is involved. Our study used lenses collected from rats after 21 or 44 d of streptozotocin diabetes. Cataracts formed in untreated 44-d streptozotocin diabetic rats, but were not apparent in the 21-d untreated diabetic animals. Lens sorbitol increased in the diabetic animals both before and after cataract formation. Lens taurine varied inversely with the sorbitol content in a fashion that resulted in no net change in total lens osmoles. Lens water did not increase in the diabetic animals with or without cataracts. The aldose reductase inhibitor Sorbinil prevented the increase in lens sorbitol in both the 21- and 44-d streptozotocin diabetic rats; cataract formation was prevented in the 44-d diabetic animals. The lens water in untreated diabetic animals with cataracts did not differ from lens water in the Sorbinil-treated diabetic animals that did not develop cataracts. Sorbinil treatment of diabetic animals was associated with normalization of both lens sorbitol and taurine levels. Taurine has been shown to serve both as an osmoregulator and as an antioxidant. The apparent increase in lens osmolality attributed to sorbitol was counterbalanced by an equimolar reduction in taurine concentration. The reciprocal relationship between taurine and sorbitol reduces the likelihood of an osmotic mechanism for sugar cataractogenesis; the reduced lens taurine, however, may increase the risk of lens protein oxidation and subsequent cataract formation. Thus in vivo sugar cataract formation may be an oxidative process rather than an osmotic phenomenon.
 ...
PMID:Nonosmotic diabetic cataracts. 213 28

The WBN/Kob rat is an animal model of spontaneously occurring diabetes only in males at the age of around one year. The diabetic cataract develops about a half year after the onset of diabetes. Using laser Raman spectroscopy we monitored WBN/Kob rat lenses which had chronic hyperglycemic stress and streptozotocin-induced diabetic rat lenses which showed relatively acute cataract formation. WBN/Kob rat lenses revealed a marked increase in the lens water content only in the cortical portion. On the other hand, streptozotocin-induced diabetic rat lenses showed a pronounced increase in the lens water content both in the cortical and the nuclear portion.
 ...
PMID:Raman study of the lenses of spontaneously-occurring and streptozotocin-induced diabetic rats. 215 May 37


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