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)

Diagnosis and management of giant cell (temporal) arteritis (GCA) should be performed by physicians who can accurately monitor the ophthalmologic, neurologic, and systemic sequelae of the disease as well as the numerous side effects of systemic corticosteroids, which are typically necessary for treatment. When the diagnosis of giant cell arteritis is seriously entertained, early treatment with adequate doses of oral or intravenous corticosteroids should not be delayed until laboratory confirmation has been obtained. Unilateral or bilateral temporal artery biopsy should be performed on all patients with suspected GCA. A positive biopsy result mandates that higher doses of corticosteroids be used during the first 2 months, which comprise the critical period for risk of new ocular ischemia. A definitive, biopsy-proven diagnosis requires at least 6 months, and typically 12 months, of corticosteroid therapy. Common pitfalls include increasing the dose and prolonging the use of corticosteroids in response to increases in the erythrocyte sedimentation rate (ESR) unrelated to GCA or visual blurring that may be related to benign tear film abnormalities, corticosteroid-induced lens changes, and other ophthalmic conditions. The muscle stiffness of polymyalgia rheumatica (PMR) must be distinguished from the osteoarthritis and other painful conditions common in the elderly. After corticosteroid therapy has begun, continuing ophthalmologic evaluation is necessary to evaluate the effectiveness of treatment and whether ocular complications, such as glaucoma or cataract, develop. Careful attention must be given to early detection and prevention of systemic side effects of corticosteroid treatment. Patients may be given gastrointestinal protective agents, such as histamine (H(2))-blocking agents; vitamin D and calcium; oral hypoglycemic agents; and, if necessary, insulin and antihypertensive drugs. If bone density measurements warrant, hormones/supplementation to prevent or reverse osteoporosis may be prescribed. After the initial diagnosis and first 4 weeks of treatment, elevation of the ESR or C-reactive protein alone should generally not be used as signs of disease activity nor as a reason to increase the daily dose of steroids. If symptoms or signs of disease activity occur, the dose should be raised regardless of test results. Even with vigorous physician-patient education, however, a patient is occasionally unable to provide adequate historical information about response to therapy, and the physician is forced to rely on laboratory values as a measure of disease activity. After initial high-dose corticosteroid therapy, patients without a classic history and with negative biopsy results will generally receive a rapid taper to low doses of corticosteroids. The role of repeated temporal artery biopsy in the clinical management of GCA is unclear. Despite persistence of PMR and, in some cases, histologic evidence of inflammation in temporal arteries, patients do not frequently have recurrence of symptomatic GCA after 6 months or more of corticosteroid therapy. Under these circumstances, late vision loss is rare.
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PMID:Giant Cell Arteritis. 1109 95

Exfoliation syndrome (XFS) is an age-related disorder of the extracellular matrix characterized by production and progressive accumulation of small, white deposits of a fibrillar extracellular material in many ocular tissues, most commonly seen on the pupillary border and anterior lens capsule. Characteristic signs of pigment liberation and deposition throughout the anterior segment aid in the diagnosis. Exfoliation syndrome predisposes to both open-angle and angle-closure glaucoma, and to capsular rupture, zonular dehiscence, and vitreous loss during cataract extraction. Exfoliation syndrome is associated with ocular and perhaps systemic ischemia. The exact chemical composition of exfoliation material remains unknown. Medical, laser, and surgical therapy are similar to treatment of primary open-angle glaucoma.
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PMID:Exfoliation syndrome. 1122 19

The calpains form a growing family of structurally related intracellular multidomainal cysteine proteinases, which exhibit a catalytic domain distantly related to papain. In contrast to papain, however, their activity in most cases depends on calcium. The calpains are believed to play important roles in cytoskeletal remodeling processes, cell differentiation, apoptosis and signal transduction, but have also been implicated in muscular dystrophy, ischemia, traumatic brain injury, neurodegenerative diseases, rheumatoid arthritis and cataract formation. The best characterized calpains are the ubiquitously expressed mu- and m-calpains, consisting of a common 30 kDa small S-subunit (domains V and VI) and slightly differing 80 kDa large L-subunits (domains I to IV). We have recently determined the 2.3 A structure of recombinant full-length human m-calpain in the absence of calcium, which reveals that the catalytic domain and the two calmodulin-like domains, previously believed to represent the unique calcium switch, are not positioned adjacent to each other, but are separated by the beta-sandwich domain III, which distantly resembles C2 domains. Although the catalytic domain of apocalpain is strongly disrupted compared to papain (which explains its inactivity in the absence of calcium), the crystal structure reveals several sites where calcium could bind, thereby causing a subdomain fusion to form a papain-like catalytic center. All current evidence points to the cooperative interaction of several calcium binding sites. Sites identified include the three EF-hand binding sites in each calmodulin-like domain, the negatively charged segments arranged around the active-site cleft (provided by both catalytic subdomains), as well as an exposed acidic loop of domain III, whose charge compensation could allow the adjacent barrel-like subdomain IIb to move toward the helical subdomain IIa. The Gly-rich S-chain N-terminus and the calcium-loaded acidic loop could target the conventional calpains to cellular/nuclear membranes, thereby explaining their strongly reduced calcium requirement in vivo and in vitro in the presence of acidic phospholipids.
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PMID:Structural basis for possible calcium-induced activation mechanisms of calpains. 1151 28

Superoxide radicals have been implicated in the pathogenesis of aging, cataract, ischemia-reperfusion, cancer and inflammatory diseases. In the present work, we found that deferiprone (L1), an iron-chelating drug, and dietary dihydroxycinnamic acids (catechols) were much more effective at protecting isolated rat hepatocytes against hypoxia-reoxygenation injury if complexed with Fe(3+). Furthermore, the 2:1 catechol-metal complexes with Cu(2+), Fe(2+), and Fe(3+) were also more effective than uncomplexed catechols in scavenging superoxide radicals generated enzymically (xanthine oxidase/hypoxanthine). The 2:1 deferiprone:Fe(3+) complex was less effective at scavenging enzymically generated superoxide radicals even though it was effective at preventing hepatocyte hypoxia-reoxygenation injury. On the other hand, the 1:1 deferoxamine:Fe(3+) complex, another iron-chelating drug, did not prevent hepatocyte hypoxia-reoxygenation injury and did not scavenge enzymically generated superoxide radicals. Furthermore, hepatocytes readily reduced the 2:1 deferiprone:Fe(3+) complex but not the deferoxamine:Fe(3+) complex. These results suggest that the initial step in superoxide radical scavenging (SRS) activity is the formation of a redox complex between Fe(3+) and deferiprone or catechols. The [deferiprone:Fe(3+)] complex was more cytoprotective than would be expected from its SRS activity. This suggests that [deferiprone:Fe(3+)] complex is reduced by a ferrireductase present on the hepatocyte membrane to form [deferiprone:Fe(2+)] complex, which then scavenges superoxide radicals. Therefore, the clinically used deferiprone (L1) may have therapeutic advantages over deferoxamine in having a double role therapeutically: (a) it chelates iron to alleviate iron overload pathology, and (b) the readily formed iron complex protects hepatocytes from superoxide radical-mediated hypoxia-reoxygenation injury.
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PMID:Iron complexes of deferiprone and dietary plant catechols as cytoprotective superoxide radical scavengers(1). 1175 10

A 52-year-old man had loss of vision and black discoloration of the lids of the right eye after a retrobulbar injection of 3 mL lidocaine hydrochloride 2% (Xylocaine). Examination of the right eye revealed no light perception with extensive necrosis of the lids. Anterior segment examination revealed conjunctival pallor, corneal edema, and necrosis of the sclera. This is a previously unreported complication of retrobulbar anesthesia comprising ophthalmic artery occlusion with scleral melt, ocular ischemia, and eyelid necrosis.
J Cataract Refract Surg 2003 Apr
PMID:Necrosis of the eyelids and sclera after retrobulbar anesthesia. 1268 60

Calpain was first discovered 30 years ago. Two major isoforms were subsequently isolated and purified. The presence of an endogenous protein inhibitor, calpastatin, was later discovered. Calpain activity is tightly regulated by Ca(2+). At physiological levels of Ca(2+), the role of calpain remains poorly understood, but is believed to be involved in mitosis and muscle cell differentiation. Calpain has also been implicated in various membrane fusion events through remodeling of the cytoskeletal network. Calpain activation has been shown to be increased during normal aging and in muscular dystrophy, cataract, arthritis and Alzheimer's disease, and in acute traumas such as traumatic brain injury (TBI), spinal cord injury and cerebral and cardiac ischemia. Early work on calpain inhibitors was limited to protein inhibitors and other nonselective enzyme inhibitors. Peptidyl aldehydes such as leupeptin and antipain are also among the earliest reported calpain inactivators. Irreversible inhibitors such as the E64 family have also been studied, and peptidyl halomethanes and diazomethanes have long been used as protease inhibitors. A variety of calpain inhibitors are under development. From a therapeutic perspective, calpain inhibitors may have several advantages over other more conventional targets such as ion channel blockers and glumate antagonists, since calpain proteolysis represents a later component of a pathway mediating cell death initiated by excitotoxicity and elevated Ca(2+) levels. Although the potential clinical utility of calpain inhibitors seems well established, a number of important considerations remain to be addressed. The role of other proteolytic cascades contributing to neuronal cell damage following TBI must also be considered.
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PMID:Potential contribution of proteases to neuronal damage. 1561 63

Clinical aspects and prognosis of corneal burns mainly depend on the agent responsible for the trauma. The most severe burns are caustic burns, which should be classified as burns caused by basic agents, associated with deep and prolonged injuries, and burns caused by acidic agents, associated with more superficial injuries. At the acute stage, caustic burns induce epithelial defects, corneal edema, and ischemic necrosis of the limbus, conjunctiva, iris and ciliary body. At the early stage, reepithelialization occurs and is often associated with corneal vascularization and stromal infiltrates, followed by corneal scar formation. At the chronic stage, the following complications are possible: corneal scars, limbal stem cell insufficiency, lachrymal insufficiency, irregular astigmatism, ocular surface fibrosis, cataract, glaucoma, decreased intraocular pressure, and ocular atrophy. The Ropper-Hall classification is based on the extent of limbal ischemia. Thermal burns induce epithelial defects at the acute stage, with the more severe forms giving the same complications as caustic burns. Radiation-related burns can be caused by ultraviolet radiations (acute epithelial keratitis, pterygium, droplet-like keratitis), microwaves, infrared radiations, ionizing radiations or, laser radiations. Electrical burns are often a result of torture and give corneal stroma opacification.
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PMID:[Clinical aspects of corneal burns]. 1568 32

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine with a range of antioxidative properties. Melatonin is endogenously produced in the eye and in other organs. Current evidence suggests that melatonin may act as a protective agent in ocular conditions such as photo-keratitis, cataract, glaucoma, retinopathy of prematurity and ischemia/reperfusion injury. These diseases are sight-threatening and they currently remain, for the most part, untreatable. The pathogenesis of these conditions is not entirely clear but oxidative stress has been proposed as one of the causative factors. Elevated levels of various reactive oxygen and nitrogen species have been identified in diseased ocular structures. These reactants damage the structure and deplete the eye of natural defense systems, such as the antioxidant, reduced glutathione, and the antioxidant enzyme superoxide dismutase. Oxidative damage in the eye leads to apoptotic degeneration of retinal neurons and fluid accumulation. Retinal degeneration decreases visual sensitivity and even a small change in the fluid content of the cornea and crystalline lens is sufficient to disrupt ocular transparency. In the eye, melatonin is produced in the retina and in the ciliary body. Continuous regeneration of melatonin in the eye offers a frontier antioxidative defense for both the anterior and posterior eye. However, melatonin production is minimal in newborns and its production gradually wanes in aging individuals as indicated by the large drop in circulating blood concentrations of the indoleamine. These individuals are possibly at risk of contracting degenerative eye diseases that are free radical-based. Supplementation with melatonin, a potent antioxidant, in especially the aged population should be considered as a prophylaxis to preserve visual functions. It may benefit many individuals worldwide, especially in countries where access to medical facilities is limited.
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PMID:Protective effects of melatonin in experimental free radical-related ocular diseases. 1644 46

Giant cell arteritis is a rare systemic vasculitis affecting large- and medium-sized arteries. Focal arteries lesions, include mononuclear cells infiltration of the vessel wall with giant cell formation. It is a disease of elderly persons and can result in a wide variety of systemic, neurological and ophthalmic complications, due to ischemia. The incidence of visual loss and ocular involvement varies between 14-88%, but one of the most common and severe complications is anterior ischemic optic neuropathy. The other ocular ischemic lesions include: central retinal artery occlusion, choroidal ischemia, diplopia, ocular motor paresis, anterior uveitis, cataract, ocular hypotony, corneal oedema and ulcerations, episcleritis and anterior scleritis, orbital cellulitis and pseudotumor. Because giant cell arteritis is potentially blinding disease, early diagnosis and immediate treatment with high dose corticosteroids may prevent further damage to the affected eye and prevent visual loss in the opposite eye. The purpose of this review is to revise established knowledge and to highlight the recent developments in diagnosis and management of giant cell arteritis.
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PMID:[A new approach towards giant cell arteritis]. 1702 3

We report a case of a 48-year-old pseudophakic woman who presented 3 weeks after Heidelberg retinal angiography using intravenous sodium fluorescein 2%. Bilateral retinal vasculitis with severe retinal ischemia and extensive capillary dropouts had been diagnosed. Anterior segment examination revealed green staining on the silicone optic of the 3-piece SI-30NB intraocular lens (IOL) (AMO), with no cell or flare in the aqueous humor. The anterior and posterior capsules were not stained. The patient did not report dark vision, double vision, or altered color vision. The anterior and posterior IOL surfaces demonstrated an autofluorescence at the time of fundus photography, which persisted to the 6-week examination although there were no symptoms. This is suggestive of deposits of sodium fluorescein on the IOL surface following angiography.
J Cataract Refract Surg 2007 Jan
PMID:In vivo fluorescein staining of SI-30NB silicone intraocular lens. 1718 15


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