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 perinuclear region of the rabbit lens is susceptible to alterations in the ionic composition of incubation medium. Rabbit lenses and a comparable cell type, red blood cells, were stressed during ex vivo incubations in isotonic modified Earle's medium with 131 mM NaCl replaced by either 232 mM sucrose or 131 mM choline chloride at pH 7.2 (normal) or 9.2. Our parallel NMR study revealed that these experimental media maintain normal intracellular pH and phosphorus metabolite levels. The present study demonstrates that lens transparency, normal fiber cell ultrastructure and volume were maintained in either sodium chloride or choline chloride containing media at normal or elevated pH. Similarly, normal morphology, mean cell volume (MCV) and mean cell hemoglobin concentration (MCHC), 86.8 +/- 0.03 micron 3 and 33.2 +/- 1.0 g dl-1, respectively, were maintained in red blood cells in either sodium chloride or choline chloride containing media. In sodium chloride deficient media at both normal and elevated pH the lens developed a nuclear cataract based on slit-lamp examination; however, SEM examination showed that fiber cell morphological abnormalities were confined to a narrow band, 50 micron wide, in the perinuclear region of the transition zone. Damage consisted of ruptured cell membranes and an absence of identifiable interdigitations with the combination of sodium chloride deficiency and elevated pH. The major abnormality produced during incubation in sodium chloride deficient medium at normal pH was the presence of numerous smooth-surfaced cellular protrusions along the vertices of the perinuclear fiber cells. In addition, the sodium chloride deficient medium, pH 9.2, produced a volume loss both in the lens and RBC (4.5 +/- 1.5% and 5.6 +/- 1.1%, respectively). The sodium chloride deficient medium, pH 7.4, produced no volume loss in the lens or red blood cells (MCV 86.0 +/- 0.05 micron 3). Further studies indicated that the cataract induced by sodium chloride deficiency (pH 9.2) is irreversible. The mechanism for perinuclear opacification due to ion deficiency remains to be elucidated.
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PMID:Morphological studies of an ion-dependent perinuclear cataract model. 318 25

The effect of sodium iodate injection on the development of galactose cataract in the rat was investigated clinically and biochemically. Galactose cataracts were induced in animals which had been injected with a single dose of sodium iodate and compared with those given a saline injection. The degeneration of retinal pigment epithelium was observed electron microscopically after sodium iodate injection. A slit lamp examination of the lens showed that, in animals injected with sodium iodate, galactose-associated lens alterations progressed faster, and mature cataract development was achieved earlier than in the saline-injected animals. Biochemical data which indicated a significantly higher concentration of Na+ and lower concentration of K+ in lenses of sodium iodate-injected animals confirmed the above clinical data. The level of galactitol was higher in lenses of sodium iodate-injected than those of saline-injected animals. Acceleration of the development of galactose cataract following sodium iodate injection is apparently due to the higher level of galactose entering the aqueous humor because of breakdown of blood-ocular barriers.
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PMID:Effect of sodium iodate injection on the development of galactose cataract in the rat. 318 99

A community based cross-sectional study on the prevalence and causes of blindness and visual impairment was carried out between August and December 1985 in the Luapula Valley. The study population consisted of 2503 villagers aged 6 years and above. Visual acuity was done on every participant whereas slit-lamp examination and ophthalmoscopy were done on selected individuals when indicated. The overall prevalence of monocular and bilateral blindness was 6.9% and 3.6% respectively. Cataracts and corneal opacities were the most common causes of visual loss in those aged 50 years and above. We conclude that blindness is an important public health problem in this valley and that this data provides a background that can be used to evaluate blindness prevention programmes that will be implemented in the future.
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PMID:Prevalence of blindness and visual impairment in the Luapula Valley, Zambia. 318 15

Seventeen women underwent simple penetrating keratoplasty for pseudophakic bullous keratopathy after extracapsular cataract extraction. Corneal edema occurred an average of eight months after cataract surgery (range, zero to 32 months). Of 17 corneal grafts, 16 (94%) have remained clear during an average follow-up period of 14 months (range, two to 32 months). One eye had a nonimmunologic graft failure. Of 16 eyes with clear grafts, 14 (87%) achieved a visual acuity of 20/40 or better after surgery. Two eyes with a visual acuity of 20/50 and 20/200 had opacified posterior capsules and one demonstrated age-related macular degeneration. One eye with a postoperative visual acuity of 20/40 demonstrated cystoid macular edema. Fifteen of 17 contralateral eyes showed slit-lamp evidence of endothelial dystrophy.
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PMID:Penetrating keratoplasty for pseudophakic bullous keratopathy after extracapsular cataract extraction. 328 36

The search for environmental factors associated with cataract has produced conflicting evidence and one possible reason may be that environmental influences are initiating events occurring perhaps for short periods many years before loss of sight from cataract. It is important, therefore, to be able to detect the earliest changes of cataract formation so that epidemiological studies have a better chance of detecting environmental factors. Two possible indicators of early cataract are delayed growth of the lens and abnormalities of the anterior subcapsular clear zone of the lens as observed on slit-lamp microscopy. A series of patients with early lens changes was compared with control subjects in respect to these two factors. Lens thickness was measured by a simple optical method. The mean thicknesses of the lens in patients with early cortical or posterior subcapsular lens changes were significantly less than that of age matched controls. 60% of lenses with early cataract of all types were found to have a deficient or absent anterior subcapsular clear zone. Lens thickness and the appearance of the anterior subcapsular clear zone are easy to measure and observe through an undilated pupil. Although the prognostic value of the results is uncertain in individual cases owing to the rather wide scatter of results in normal eyes, such observations could be of value in comparative studies of populations.
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PMID:Lens thickness in early cataract. 329 52

The objective assessment of cataract is central to any epidemiological or therapeutic study of cataract. The objective methods consist of: 1: A resolution target projection ophthalmoscope (Acuity scope) for the estimation of potential visual acuity. 2: The Oxford Clinical Cataract Classification and Grading System, which records and quantifies the features of the lens that are visible at the slit-lamp microscope. This system is essential since photographic methods cannot define the morphology of cataract. 3: Two photographic methods; slit-lamp photography and retro-illumination photography are needed to give a comprehensive statement about the amount of cataract. The negatives are measured by computerised image analysis systems.
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PMID:The objective assessment of cataract. 330 27

Preoperative and serial postoperative anterior chamber fluorophotometry were performed after oral administration of fluorescein sodium in patients undergoing extracapsular cataract extraction and posterior chamber intraocular lens insertion. The administration of topical 0.5% ketorolac tromethamine solution before and after surgery markedly decreased the breakdown of the blood-aqueous barrier compared with vehicle-placebo solution administration at each time period, as measured by fluorophotometry. Corticosteroids were not given to any patients throughout the duration of the study. These fluorophotometric results correlated well with slit-lamp observations of postoperative ocular inflammation. Both ketorolac and vehicle were well tolerated by patients. No effects on intraocular pressure were seen with ketorolac administration. This study suggests that ketorolac ophthalmic solution is effective and safe as a nonsteroidal anti-inflammatory agent for topical use following cataract surgery and intraocular lens implantation.
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PMID:Quantitative assessment of postsurgical breakdown of the blood-aqueous barrier following administration of 0.5% ketorolac tromethamine solution. A double-masked, paired comparison with vehicle-placebo solution study. 334 53

Anterior chamber fluorophotometry was performed after the oral administration of fluorescein sodium in patients undergoing extracapsular cataract extraction and posterior chamber intraocular lens insertion before and after surgery. The administration of 0.5% ketorolac tromethamine solution (ketorolac solution) eye drops before and after surgery decreased the breakdown of the blood-aqueous barrier as compared with 0.1% dexamethasone sodium phosphate solution (dexamethasone solution) eye drops at each period, as measured by fluorophotometry. A single injection below Tenon's capsule of a short-acting corticosteroid had been given to each patient at the end of each surgical procedure. Slit-lamp observations of postoperative ocular inflammation were not different between treatment groups. Both ketorolac and dexamethasone solutions were well tolerated by patients. Ketorolac solution was more effective than dexamethasone solution in facilitating reestablishment of the blood-aqueous barrier after surgery, as measured by fluorophotometry, and was equal to dexamethasone solution as observed by slit-lamp observations. This study suggests that ketorolac ophthalmic solution may be effective and safe as a nonsteroidal anti-inflammatory agent for topical use after cataract surgery and intraocular lens implantation in place of topically administered corticosteroids.
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PMID:The quantitative effect of 0.5% ketorolac tromethamine solution and 0.1% dexamethasone sodium phosphate solution on postsurgical blood-aqueous barrier. 335 15

Acetaminophen has been shown to be cataractogenic in mice and rabbits. C57BL/6 and DBA/2 mice respectively are genetically susceptible and resistant to the induction of cytochrome P-448 by 3-methylcholanthrene (3-MC). This isoenzyme is thought to bioactivate acetaminophen to a toxic reactive intermediate. These two murine strains also are correspondingly susceptible and resistant to acetaminophen cataractogenesis. To evaluate the potential role of enzymatic bioactivation as a determinant of acetaminophen cataractogenesis, C57BL/6 and DBA/2 mice were treated with acetaminophen, 300 or 400 mg/kg intraperitoneally (ip), with or without pretreatment 48 hr earlier using 3-MC, 200 mg/kg ip. Lenticular cataracts were evaluated using the unaided eye and a slit lamp, and hepatotoxicity was evaluated by determination of peak plasma concentration of alanine aminotransferase (ALT). Plasma concentrations of acetaminophen and metabolites, particularly the glutathione (GSH)-derived conjugates (cysteine and mercapturic acid) reflecting enzymatic bioactivation, were measured by high-performance liquid chromatography. Cataracts developed only in C57BL/6 mice pretreated with 3-MC, occurring in 1 of 5 and 5 of 5 animals treated respectively with 300 and 400 mg/kg of acetaminophen. Comparing these two groups of induced C57BL/6 mice, production of the cysteine conjugate of acetaminophen was 2.5-fold higher with the 400 mg/kg dose of acetaminophen (p less than 0.05). Compared to their respective dose-matched, noninduced controls, cysteine conjugate production in the 300 and 400 mg/kg dose groups of induced C57BL/6 mice respectively was 3-fold and 4-fold higher (p less than 0.05). No DBA/2 mice developed cataracts. No mercapturic acid conjugate was detectable in the plasma of DBA/2 mice, and production of the cysteine conjugate was not altered in this strain by increasing the dose of acetaminophen or by pretreatment with 3-MC. The mean peak plasma concentration of the cysteine conjugate, reflecting acetaminophen bioactivation, was 5-fold higher in animals developing cataracts compared with those without cataracts (p less than 0.001). Plasma concentrations of unmetabolized acetaminophen were similar in all groups and unrelated to the development of cataracts. All mice of both strains pretreated with 3-MC showed evidence of hepatotoxicity, indicating a dissociation between hepatotoxic and cataractogenic susceptibility.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Metabolic evidence for the involvement of enzymatic bioactivation in the cataractogenicity of acetaminophen in genetically susceptible (C57BL/6) and resistant (DBA/2) murine strains. 340 97

The nuclear colour of in vivo human lenses has been investigated by means of a colour matching technique, using 'Munsell' colour samples. Observations covered an extended age range, and included all degrees of nuclear pigmentation. A positive correlation was noted between increasing nuclear pigmentation and age. The colour matching data generated was used as a basis for establishing a system of nuclear brunescence grading. The system of grading consists of a Grade 0 for absence of brunescence, and Grade 1 to Grade 5 for increasing brunescence. The 'Munsell' notation for samples representing these grades are: Grade 0 (5GY 6/1), Grade 1 (5Y 7/4), Grade 2 (2.5Y 7/8), Grade 3 (7.5YR 6/8), Grade 4 (5YR 4/6), and Grade 5 (2.5YR 2.5/2). Assessments of both inter- and intra-observer variability in the use of the derived scale have shown the new colour grading system to be reliable. The measure is simple to use during biomicroscopic slit-lamp examination of the lens, and has the potential for routine clinical application as well as for use in clinical trials where detailed documentation of lens morphology is required. The new colour scale may be used either as an isolated measure, or as part of a battery of lens measures in the Oxford Clinical Cataract Classification and Grading system.
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PMID:Human lens nuclear colour matching and brunescence grading in vivo. 341 86


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