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)

To determine the possible role of glucose and lipid metabolism in the formation of cataract in elderly people we studied 463 patients undergoing cataract extraction. Of 188 males, 35 (19%) had posterior subcapsular cataract (group 1), 27 (14%) had cortical cataract (group 2), and 24 (13%) had nuclear cataract (group 3). Of 275 females, 27 (10%) belonged to group 1, 44 (16%) to group 2, and 33 (12%) to group 3. Patients in group 1 were significantly younger than those of group 2 and 3. In addition, patients in group 1 had higher concentrations of fasting serum triglycerides than patients of group 2 or 3. No difference in mean concentrations of serum cholesterol was observed between the different groups. However, fasting plasma glucose concentrations were higher in group 1 patients than in those of group 2 or 3. Patients in group 1 had a higher 'Broca index' than those in group 2 or 3, with the exception of males in group 3. These results suggest that the association of hypertriglyceridemia, hyperglycemia and obesity favors the formation of a specific morphologic type of lens opacity, posterior subcapsular cataract, occurring at an early age. They imply the possibility of effective modes of preventive therapy for a subgroup of patients with 'senile' cataract.
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PMID:Identification of metabolic risk factors for posterior subcapsular cataract. 373 11

It was shown that human lens opacity was accompanied by the decrease in the lens ability to cleave H2O2 (10(-4) M), added to the lens-surrounding medium. The rate of peroxide decomposition at the stage of mature cataract in isolated human lenses was 3.5 times lower than that of the control human lenses (transparent lens, initial cataract). Specific catalase inhibitor--3-amino,IH-1,2,4-triazole showed no significant influence on the rate of H2O2 cleavage. Reduced glutathione (10 microM) added to the lens incubation medium induced a sharp increase in the rate of H2O2 detoxication. The results indicate that reduced glutathione metabolism is of primary importance in the maintenance of anti-peroxide activity in the lens.
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PMID:[Decomposition of H2O2 by human cataractous lenses]. 374 26

6 mice with inherited cataracts and 1 new allele of microphthalmia were recovered from 923 progeny of untreated, outbred, PT stock females that had been mated to inbred C3H/HeH strain males, whose spermatogonia had been exposed to 250 mg/kg of ethylnitrosourea (ENU). The cataract phenotypes were quite variable in expression and 5/6 showed a similar range of phenotypes. 2 of the 6 mutant mice were daughters of the same ENU-treated C3H/HeH male and probably represent repeats of the same mutation. One mutation, designated lens opacity-4 (Lop-4), has been genetically mapped to the distal region of chromosome 2. The yield of 5 presumably independent cataract mutations from 923 F1 offspring is a little higher than that reported by others in similar but larger scale experiments. Approximately 3-5% of the F1 mice examined had cataracts, yet only 6/49 (12%) of these, in the experimental group, were inherited as simple Mendelian traits. We consider that this high frequency of false positives (88%), and the incomplete penetrance and variable expressivity of the cataract mutations that were found, pose serious problems that could undermine the objective nature of the dominant cataract mutation test. We suggest that further studies be made to evaluate whether the use of inbred strains would reduce the variability in the system and so make the test more objective. However, it seems likely that the high false positive rate will continue to be a serious drawback to this test system.
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PMID:Further experience of the mouse dominant cataract mutation test from an experiment with ethylnitrosourea. 375 5

Liposome suspension prepared from the unsaturated phospholipids exposed to lipid peroxidation (LPO) induced posterior subcapsular cataracts after injection into the posterior vitreous of rabbit eyes. In the background of this model lies a type of lens opacity formed during retinal degeneration when toxic peroxide substances diffuse anteriorly through the vitreous body resulting in vitreous opacities and complicated cataracts. Saturated liposomes (prepared from beta-oleoyl-gamma-palmitoyl) L-alpha-lecithin) did not induce lens opacities, which is the evidence that a lipid peroxidation mechanism may be responsible for the posterior cataracts. Along with cataract formation accumulation of LPO fluorescent products in vitreous, aqueous humor and lens was observed. It was followed by a decreased level of reduced glutathione in the lens. The obtained results strongly support the hypothesis of LPO initial role in cataracts.
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PMID:[Cataract induction by products of lipid peroxidation]. 381 30

To determine the long-term cutaneous side-effects of oral photochemotherapy (PUVA), we examined 95 patients, 59 with psoriasis and 36 with mycosis fungoides (MF). These comprised 80% and 69% respectively of the patients with these disorders treated with PUVA in our department from 1977 to 1985. Two psoriatic patients had squamous carcinomas, both of whom had received high cumulative UVA doses and also methotrexate concurrently with PUVA. Six patients with MF had actinic keratoses. The mean age of these patients (69 years) was significantly greater than the mean age of the patients without actinic keratoses (54 years), but there was no significant difference in their cumulative UVA doses. No patients developed basal cell carcinomas or malignant melanoma. 'PUVA lentigines' were found in 46% of the patients. They were most frequent in patients currently being treated and in those who had received high cumulative UVA doses, but persisted for up to 7 years after discontinuing therapy. Seventy-one patients had yearly ophthalmological examinations, or a single examination at least 3 months after commencing PUVA. This examination included retinal function tests to detect any subclinical visual impairment. Five of these patients had cataract prior to PUVA therapy, and were significantly older (mean age 71 years) than those without cataract (mean age 53 years). Three patients (mean age 61 years) developed new lens opacities whilst receiving PUVA. However, none of these patients was considered to have cataract as none had impairment of visual acuity due to lens opacity. No patients without lens opacity developed evidence of subclinical visual impairment.
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PMID:Cutaneous and ocular side-effects of oral photochemotherapy: results of an 8-year follow-up study. 382 11

Cataract disrupts the crystalline lens, a transparent, elastic, avascular, biconvex structure composed of a capsule, lens epithelium, and lens fiber cells. Many factors contribute to the progression of lens opacity, but aging is most frequently associated with cataract. As aging-related cataract develops, many biochemical and biophysical changes occur, most notably a marked increase in the insolubilization of the crystallin and extensive oxidation damage to many of the lens constituents. Cataract management should include ophthalmologic history and examination, medical evaluation, optical correction, control of ocular and systemic disease that may contribute to cataract, discontinuation of cataractogenic drugs, and periodic reexamination. Surgery is indicated when cataract is associated with vision decrease interfering with activities important to the patient, intraocular inflammation or glaucoma, or interference with management of posterior segment disease. More than 600 000 cataract operations are done in the United States each year; in 1982 an estimated 496 000 cataract operations were combined with intraocular lens implantation.
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PMID:Aging-related cataract: laboratory investigation and clinical management. 388 Oct 70

Content of primary (diene conjugates), secondary (ketodienes), end (Schiff's bases) products of free radical oxidation (FRO) of lipids was determined, as well as content of total and non-protein-bound thiols in human lens at different stages of cataractogenesis. Lens opacity was estimated by quantitative morphometric analysis. Participation of FRO of lipids in lens opacity is proved. It is shown that total thiols of lens fibres are rapidly inactivated when the intensity of lipid FRO is increased at the expense of the fall of glutathione level. These processes promote the formation of high molecular protein aggregates in the lens and cataract development. Coefficients of linear correlation between the indicated parameters are presented. A conclusion is drawn concerning possible prevention of cataract development by decreasing the level of accumulation of lipid peroxides and by maintaining high concentration of reduced glutathione in the lens.
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PMID:[Free radical oxidation of lipids and thiol groups in the formation of a cataract]. 395 83

With a fixed time period of galactose feeding, the rate of appearance of lenticular opacities depended on the severity of galactosemia, while with a fixed amount of galactose fed, the rate was time dependent. The capacity of tolrestat, a structurally novel inhibitor of aldose reductase (AR), to control cataract development was assessed in rats fed 30-50% galactose with the diet for 7 to 277 days. In rats fed 30% galactose for 31 days, the controlling effect of tolrestat was dose dependent, and no cataracts were detected at a dose of 35 mg/kg/day. In rats given tolrestat with the diet for 14 days, then rendered severely galactosemic with a diet containing 50% galactose, and subjected to continued treatment with tolrestat at a dose of 43 mg/kg/day, no changes were detected by slit-lamp microscopy after 207 days. The preventive effect was also dose dependent. In view of the established similarity in the pathogenesis of galactosemic and diabetic cataracts, the results obtained with tolrestat support its potential for controlling cataract development in diabetics.
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PMID:Prevention of cataract development in severely galactosemic rats by the aldose reductase inhibitor, tolrestat. 398 36

This study examined the contribution of the crystalline lens to the spatial contrast sensitivity loss experienced by many healthy older adults. Spatial contrast sensitivity was measured in three groups of adults: older adults who had undergone cataract extraction and intraocular lens (IOL) insertion; older adults who were in good ocular health (agematched to the first group); and young adults also in good ocular health. Older adults had decreased contrast sensitivity at higher spatial frequencies compared to young adults, agreeing with earlier reports. In addition, both groups of older adults had similar contrast sensitivity at higher frequencies, contrary to what would be expected if the aged, noncataractous crystalline lens significantly hampered contrast transfer in the healthy older eye. Results imply that the crystalline lens is not primarily responsible for the spatial sensitivity loss of healthy older adults. Furthermore, these data indicate that for at least some IOL patients, spatial vision can be restored to a level similar to their agemates who have no history of lens opacity or ocular disease.
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PMID:Role of the crystalline lens in the spatial vision loss of the elderly. 401 9

High-intensity focused ultrasound was employed to seal lens capsular tears in a rabbit model. Ultrasound therapy was applied either contiguously, thereby completely covering the tear, or in a discrete exposure pattern around the tear. Both methods prevented the formation of a generalised cataract. This was in contrast to results observed in a group of control (untreated) animals which all developed generalised lens opacities. Each control animal also developed a local lens opacity at the site of the capsular tear, as did half the animals treated with the discrete pattern. No animal treated with contiguous exposures developed any local or generalised traumatic-type cataract other than the small lens opacity immediately produced by the treatment. These treatment cataracts would not constitute a significant impediment to vision so long as they did not fall on the visual axis.
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PMID:Treatment of experimental lens capsular tears with intense focused ultrasound. 404 9


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