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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A remarkable resemblance between the appearance of opacity in lysozyme--salt water mixtures and the development of opacity in cold cataract in the young rat lens is strong evidence that cold cataract is fundamentally a phase separation of the "protein-water binary mixture" in the lens.
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PMID:Phase separation of a protein-water mixture in cold cataract in the young rat lens. 88 36

Surgical solutions and drugs are important in ocular surgery. These include irrigating solutions, viscoelastic substances, mydriatics and miotics, and a growing number of other agents designed to enhance intraocular surgery and its outcome. Potential for damage to the corneal endothelium and other tissues is related to the chemical composition, pH, and osmolality of the irrigating solutions that bathe tissues. Quality balanced salt solutions (BSS) are usually safe for use as an intraocular solution in patients with normal corneal endothelium. If prolonged irrigation times are expected, or the patient already has decompensated endothelium, i.e., primary or secondary endotheliopathy, the use of a "complete" BSS solution is indicated to minimize damage. Intraocular sulfite-containing epinephrine may cause severe corneal edema and should be avoided, or if used, be well diluted. Sulfite-free epinephrine solution is now available and does not cause the endothelial toxicity that one may see with sulfite-containing epinephrine solutions. Current formulations of acetylcholine and carbachol used as miotics in surgery have been evaluated in humans and caution is recommended in using acetylcholine solutions intracamerally in patients with already decompensated endothelium. Chondroitin sulfate, hydroxypropyl methylcellulose, and sodium hyaluronate are non-toxic to animal endothelial cells under conditions analogous to cataract extraction in humans but can be toxic to endothelium if there is continued contact with endothelium for hours. Chondroitin sulfate has been shown to have more of a protective effect in mechanical pseudophakos trauma probably because of its cohesiveness and tendency to coat the endothelium. Viscoelastics cause a significant rise in intraocular pressure of > 30 mm Hg in 3-10% of patients. Very high intraocular pressures are often seen postoperatively after viscoelastic use surgically in patients who preoperatively have a history of ocular hypertension or glaucoma.
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PMID:Overview of the corneal toxicity of surgical solutions and drugs: and clinical concepts in corneal edema. 130 90

Ocular modifications were assessed in a prospective study carried out on 61 chronically hemodialyzed patients. Their mean age was 39.6 years (range: 7-73 yr) and the mean duration of dialysis was 30.5 months. The loss of visual acuity was especially associated with cataracts or refractive disorders. Corneal-conjunctival calcifications were found in 36% of the patients and were statistically significantly correlated with the duration of hemodialysis. Eyeground modifications were observed in 36% of the subjects; 21.3% of them were hypertensive retinopathies. Cataracts were less common (5%) than small calcifications in the lens (24.5%). Conjunctival biopsies taken from two patients confirmed the presence of calcium salt deposits under the conjunctival epithelium.
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PMID:[Ophthalmologic manifestations in patients under chronic hemodialysis]. 148 43

Posterior capsule opacification is a common postoperative complication after extracapsular cataract extraction and lens implantation. If the patient's visual acuity is reduced markedly, a capsulotomy with a Nd-YAG laser may become necessary. Various attempts have been made with the aim of developing an injectable solution capable of damaging the epithelial cells of the capsule bag irreversibly and thereby avoiding posterior capsule opacification. This solution should be applied for a short time during the operation. In tissue culture we tested the influence of two injectable solutions [lens epithelial necrosis factor (LENF)] and aqua bidest. on cellular growth. Balanced salt solution served as control. We used human epithelial carcinoma cells, type HEp-2. The results were evaluated by vital staining (ethidium bromide and acridin orange), hemotoxylin staining, autoradiography and measurement of protein and DNA synthesis. The results showed that LENF is capable of damaging 100% of the epithelial cells irreversibly if it is applied for 20 s or longer. The influence of each of these solutions was tested on 20 human capsular flaps, which were excised during the operation. The flaps were immersed for 30 s in the different solutions. Vital staining of these flaps led to the following results: LENF causes a 100% cell damage of all epithelial cells of the capsular flaps. No vital cells remained. On the other hand Aqua bidest. cannot guarantee 100% cell damage of the capsular flap epithelia. Sixty percent of the capsular flaps treated with aqua bidest, showed differing amounts of remaining vital cells.
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PMID:[Lens epithelium necrosis factor for prevention lens opacity]. 178 27

Twenty samples of 2% hydroxypropylmethylcellulose for intraocular surgery, obtained from two Brazilian laboratories, were studied to determine the presence and type of impurities in the solutions. These were compared with ten samples of balanced salt solution (control group). Using light and scanning electron microscopy, five types of particles were identified: cellulose fibers, vegetable flakes, crystals, glass fragments, and other impurities. At least one of these contaminants was present in each sample of 2% hydroxypropylmethylcellulose. The vegetable matter was also seen in a sample of the raw material from which the clinical material had been prepared. Control solutions (i.e., balanced salt solution) were free of vegetable matter and of crystals, but glass fragments and other impurities were present. The average number of foreign particles in the solutions of hydroxypropylmethylcellulose (91.2 and 96.7 particles per milliliter for each of the two groups) was statistically greater than in the balanced salt solutions (13.7 particles per milliliter).
J Cataract Refract Surg 1991 Jul
PMID:Light and electron microscopic analysis of intraocular 2% hydroxypropylmethylcellulose. 189 25

Bendazac is a drug which protects proteins from denaturation induced by different agents. It is also effective in protecting rabbits from X-ray-induced cataract. This study deals with the effects of bendazac on the intense light-induced retinal damage in rats. Four groups of animals received orally 0, 50, 100 or 200 mg/kg of bendazac L-lysine salt three times a day for 3 days and once the fourth day, before 1 h exposure to intense-green filtered light. Fourteen days after housing in a dark room, the rats were sacrificed and the retinae were examined by light microscopy. Retinal damage was graded according to a score severity from 0 to 5. The mean score for control animals was 2.23, whereas a dose-related and statistically significant reduction of retinal damage was detected in bendazac treated rats, i.e. 1.72, 1.54 and 1.40. A protective activity in the distribution of the severity score, i.e. a higher incidence of no damaged retinae and a lower frequency in the most severely affected ones, was also observed in treated versus control rats. These results suggest a potential therapeutic value of bendazac in the treatment of those conditions, such as retinitis pigmentosa and senile macular degeneration, in which the light exposure plays a role as a co-factor.
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PMID:Pretreatment with bendazac attenuates retinal damage induced by intense light in rats. 194 39

Because the organogenesis and physiology of the lens are essentially similar in various mammals, an understanding of the etiology and pathogenesis of the formation of cataract in an animal model will enhance our knowledge of cataractogenesis in man. In this review, we summarize the background, etiology, and pathogenesis of cataracts that occur in rodents. The main advantages of using rodent mutants include the well-researched genetics of the animals and the comparative ease of breeding of large litters. Numerous rodent models of congenital and hereditary cataracts have been studied extensively. In mice, the models include the Cts strain, Fraser mouse, lens opacity gene (Lop) strain, Lop-2 and Lop-3 strains, Philly mouse, Nakano mouse, Nop strain, Deer mouse, Emory mouse, Swiss Webster strain, Balb/c-nct/nct mouse, and SAM-R/3 strain. The rat models include BUdR, ICR, Sprague-Dawley, and Wistar rats, the spontaneously hypertensive rat (SHR), the John Rapp inbred strain of Dahl salt-sensitive rat, as well as WBN/Kob, Royal College of Surgeons (RCS), and Brown-Norway rats. Other proposed models for the study of hereditary cataract include the degu and the guinea pig. Because of the ease of making clinical observations in vivo and the subsequent availability of the intact lens for laboratory analyses at different stages of cataract formation, these animals provide excellent models for clinicopathologic correlations, for monitoring of the natural history of the aging process and of metabolic defects, as well as for investigations on the effect of cataract-modulating agents and drugs, including the prospect of gene therapy.
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PMID:Rodent models of congenital and hereditary cataract in man. 195 36

The clinical progression of the cataract may be influenced by drugs which reduce the denaturation of lens proteins. One of the most promising drugs is the bendazac-lysine salt. The drug was used in a double-blind study of a group of patients with initial cortical cataract in order to evaluate the changes in visual acuity and contrast sensitivity by means of a psychophysical and an electrophysiological method. After 6 months of treatment with bendazac the mean values of visual acuity showed a statistically significant increase in respect to baseline values, as well as an improvement of the threshold of contrast for most spatial frequencies. In the eyes treated with placebo there was no statistical difference between the visual acuity at baseline and after the treatment, but an increase of the contrast threshold for many spatial frequencies. The treatment with bendazac, when compared to the administration of placebo, leads to a statistically significant improvement of the contrast threshold and induces a global improvement on the visual conditions.
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PMID:Psychophysical and electrofunctional contrast sensitivity in cataractous patients treated with bendazac-lysine salt. 210 31

Bendazac is an oxyacetic acid with anti-inflammatory, antinecrotic, choleretic and antilipidaemic properties, but its principal effect is to inhibit the denaturation of proteins. The lysine salt, which is better absorbed than the parent compound after oral administration, has been evaluated as a treatment for cataract, a condition which appears to result mainly from the denaturation, aggregation and precipitation of proteins within the lens. Results from a very small number of preliminary studies using objective photographic and densitometric methods have suggested that oral bendazac lysine, usually at a dosage of 500 mg 3 times daily, can stabilise the progression of lens opacification in patients with cataract. Significant improvements in individual and mean visual acuities in treated patients have been reported by several studies, but this parameter is not universally accepted as a reliable index of lens status. Preliminary studies evaluating bendazac lysine 0.5% eyedrops have reported comparable results to those obtained with oral treatment. Overall, tolerability of the drug has been good in studies to date. A dose-related laxative effect and other gastrointestinal disturbances are the most common adverse effects associated with oral therapy, and a transient burning sensation is the most commonly reported symptom occurring with eyedrop application. Bendazac lysine is one of a number of agents which have been introduced for the management of cataract. Although the results of preliminary studies have suggested that the drug may be useful for delaying the progression of cataract, further clinical studies using proven objective methods are required to fully establish its value in the management of this condition and its long term tolerability.
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PMID:Bendazac lysine. A review of its pharmacological properties and therapeutic potential in the management of cataracts. 219 Jul 95

Our earlier studies of cataracts in Dahl salt-sensitive (DS) rats suggested the possibility of altered lens ion transport as a contributing factor in cataractogenesis in this genetic model. We also observed that those weanling DS rats with the greatest pressor response to a high salt diet eventually developed cataracts, and that changes in salt intake modified cataract formation. In the present studies, we measured lens 86Rb uptake as an index of sodium-potassium adenosine triphosphatase [(Na+,K+)-ATPase] activity in weanling DS rats before the development of cataracts or sustained hypertension. Additionally, plasma renin activity was measured to indirectly assess our hypothesis that the difference between cataract-prone DS rats and DS rats unlikely to develop cataracts might be a difference in degree of salt sensitivity. At the age of 4 weeks, 50 DS and 25 salt-resistant (DR) rats were given a high sodium diet for 2 weeks, at which time the rats were divided into three groups based on the systolic blood pressure response, that is, cataract-prone DS rats with systolic blood pressure equal to or greater than 155 mm Hg, DS rats unlikely to develop cataracts with systolic blood pressure less than or equal to 125 mm Hg, and DR rats. Lens and aqueous humor Na+ and K+, lens dry weight, and water content were not significantly different among the three groups of weanling rats. Plasma renin activity was lowest in cataract-prone DS rats and low in DS rats unlikely to develop cataracts when compared with values in DR rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lenticular rubidium uptake and plasma renin activity in weanling cataract-prone salt-sensitive rats. 240 57


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