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)

Collamer (collagen-acryl copolymer) intraocular contact lenses were implanted in the posterior chamber (sulcus) in phakic eyes to correct severe myopic patients. In addition to being myopic, they had visual problems (diminishing, contact lens coating) or direct organic eye problems (keratitis, conjunctivitis, vessel ingrowth in cornea) wearing glasses or standard contact lenses in everyday life. Seven lenses were implanted in four patients with preoperative myopia (spherical equivalents) ranging from -8.75 to -20.5 diopters (D), average myopia was -15.4, average follow up was 13.2 months. Mean postop myopia (spherical equivalent) was -1.96. Best spectacle-corrected visual acuity improved in all eyes with approximately two lines in Snellen's chart. No iritis or cataract was observed; one anterior angel closure required an additional iridotomia in one eye. The lens was well accepted, and a good functional outcome occurred within a short delay. The method holds promise as an important supplementary treatment for patients with severe refraction anomalies. It is, in fact, the only treatment for the most severe myopic and hypermetropic patients if they are to preserve their accommodative abilities.
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PMID:[Intraocular contact lens to correct severe refractive error]. 1039 75

Fechtner syndrome is an autosomal-dominant variant of Alport syndrome, manifested by nephritis, sensorineural hearing loss, cataract formation, macrothrombocytopenia, and polymorphonuclear inclusion bodies. As opposed to autosomal-recessive and X-linked Alport syndromes, which have been genetically well studied, the genetic basis of Fechtner syndrome remains elusive. We have mapped the disease-causing gene to the long arm of chromosome 22 in an extended Israeli family with Fechtner syndrome plus impaired liver functions and hypercholesterolemia in some individuals. Six markers from chromosome 22q yielded a LOD score >3.00. A maximum two-point LOD score of 7.02 was obtained with the marker D22S283 at a recombination fraction of 0. Recombination analysis placed the disease-causing gene in a 5.5-Mb interval between the markers D22S284 and D22S1167. No collagen genes or genes comprising the basement membrane have been mapped to this region.
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PMID:Genetic linkage of autosomal-dominant Alport syndrome with leukocyte inclusions and macrothrombocytopenia (Fechtner syndrome) to chromosome 22q11-13. 1057 25

We have used synchrotron x-ray diffraction to obtain quantitative information about the precise orientation of the collagen fibrils in the human cornea and sclera, and how these fuse at the limbus. We have shown that the human corneal stroma has preferred collagen orientation in the inferior-superior and nasal-temporal directions. At the limbus, however, the preferred orientation is tangential to the cornea. We demonstrated that these limbal fibrils are in the form of a circumcorneal annulus and quantified how this annulus varies with position. We have also started to unravel how the corneal collagen fibrils fuse with the collagen in the annulus. The results have both mechanical and surgical implications. Keratoplasty is performed without considering the preferred directions of the collagen fibrils. Surgery is increasingly used to correct astigmatism and myopia. The site and direction of an incision during, for example, cataract surgery, can influence the eventual level of astigmatism. X-ray diffraction helps our understanding of the underlying structural and hence mechanical reasons for refractive problems following surgery.
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PMID:Organization of collagen fibrils in the corneal stroma in relation to mechanical properties and surgical practice. 1059 12

Alport syndrome is an inherited disorder of type IV collagen, a major constituent of basement membranes. Eighty-five percent of cases are transmitted through X-linked dominant inheritance, although autosomal dominant and autosomal recessive inheritance has also been reported. Clinical manifestations of Alport syndrome include progressive glomerulopathy, sensorineural deafness, anterior lenticonus, posterior corneal dystrophy, and abnormal retinal pigmentation. Anterior lenticonus may lead to loss of vision because of progressive myopia or cataract formation. We report 2 cases of unusual cataract formation in adolescent boys who had a rupture of the anterior lens capsule. One rupture was spontaneous, and the other was traumatic.
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PMID:Rupture of the anterior lens capsule in Alport syndrome. 1104 Apr 88

Recent work has explored the potential deleterious role that nitric oxide (NO) and its derivatives may have in human disease. The many by-products of NO include nitrite ion, which accumulates in the anterior chamber during ocular inflammation and can be derived from cigarette smoking. Cigarette smoking has been strongly linked to nuclear cataract formation, although the mechanism remains unknown. We have previously observed that nitrite reactions with the matrix proteins elastin and collagen produce damaging effects that mimic those observed in age- and smoking-related illnesses. In the present study we report on the reaction of nitrite with alpha crystallin, the major lens matrix protein. Incubations at neutral pH and body temperature of nitrite with alpha crystallin resulted in protein modifications indicative of oxidative damage and similar to changes seen in the aging lens as well as cataracts. These include increased fluorescence, yellowing and protein cross-linking. L-kynurenine, a tryptophan derivative, was identified as a reaction product. L-kynurenine was also formed from the reaction of nitrite with free tryptophan. Thus, this non-enzymatic nitration of alpha crystallin provides a novel mechanism by which lens proteins may be damaged in vivo. Since human exposure to nitrite is increased by cigarette smoking, this reaction could provide an explanation for the association between nuclear cataracts and smoking.
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PMID:The Nitrite/alpha crystallin reaction: a possible mechanism in lens matrix damage. 1064 22

We determined the "normal" central corneal thickness (CCT) value in human corneas based on reported literature values for within-study average CCT values, and used this as a reference to assess the reported impact of physiological variables (especially age and diurnal effects), contact lens wear, pharmaceuticals, ocular disease, and ophthalmic surgery on CCT. With the expected CCT and its variance defined, it should be possible to determine the potential impact of differences in CCT in intraocular pressure (IOP) assessments, especially by applanation tonometry, using a meta-analysis approach. Some 600 sets of CCT data were identified from the worldwide literature over the period of 1968 through mid-1999, of which 134 included IOP measures as well. The within-study average CCT values and reported variance (SD) was noted along with the number of eyes and any special characteristics, including probable ethnic origin of the study subjects. Various sets of data were subjected to statistical analyses. From 300 data sets from eyes designated as normal, the group-averaged CCT was 0.534 mm. From 230 data sets where interindividual variance was reported, the group-averaged CCT was 0.536 mm (median 0.536 mm; average SD of 0. 031 mm, average coefficient of variation = 5.8%). Overall, studies using slit-lamp-based pachometry have reported marginally lower CCT values (average 0.530 mm, average SD 0.029 mm) compared to ultrasound-based studies (average 0.544, average SD 0.034 mm), which perhaps reflects the type of individual studied (non-surgical vs. pre-surgical patients) rather than the technique itself. A slight chronological increase in reported average CCT values (approximately 0.006 mm/decade) was evident, but a substantial chronological increase was evident for ultrasound pachometry studies (approximately 0.015 mm/decade). Within the meta-analysis-generated average and variance, age had no obvious impact on CCT measures for *whites, although an age-related decline in CCT is evident for non-whites. Any diurnal effects are likely concealed within the expected variance in CCT. Contact lens wear and pharmaceuticals generally produced changes in CCT that were well within the expected variance in CCT. Of the ocular diseases, only those associated with collagen disorders (including keratoconus) or endothelial-based corneal dystrophies (e.g., Fuchs) were likely to result in decreases or increases, respectively, of CCT beyond the normal variance. Routine contact lens wear and diseases such as diabetes seem unlikely to produce changes in CCT of a magnitude that would justify pachometry as a monitoring method beyond routine slit-lamp evaluation. Increases in CCT beyond the expected variance were reported after a range of intraocular surgeries (cataract operations, penetrating keratoplasty), whereas photorefractive surgery produces a measurable decrease in CCT. A meta-analysis of possible association between CCT and IOP measures of 133 data sets, regardless of the type of eyes assessed, revealed a statistically significant correlation; a 10% difference in CCT would result in a 3. 4 +/- 0.9 mm Hg difference in IOP (P </= 0.001, r = 0.419). The observed phenomenon was much smaller for eyes designated as healthy (1.1 +/- 0.6 mm Hg for a 10% difference in CCT, P = 0.023, r = 0. 331). For eyes with chronic diseases, the change was 2.5 +/- 1.1 mm Hg for a 10% difference in CCT (P = 0.005, r = 0.450), whereas a substantial but highly variable association was seen for eyes with acute onset disease (approximately 10.0 +/- 3.1 mm Hg for a 10% difference in CCT, P = 0.004, r = 0.623). Based on the meta-analysis, normal CCT in white adults would be expected to be within +/-11.6% (+/-2 SD) of 0.535 mm, i.e., 0.473-0.597 mm (95% CI, 0.474-0.596). The impact of CCT on applanation tonometry of healthy eyes is unlikely to achieve clinical significance, but for corneas of eyes with chronic disease, pachometry should be performed if the tonometry reveals IOP readi
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PMID:Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach. 1073 39

Nonpenetrating deep sclerectomy is a filtration surgical technique to treat glaucoma. A 12-year-old girl presented with chronic arthritis complicated with glaucoma secondary to a chronic uveitis. A sclerectomy without a collagen implant was performed for uncontrollable glaucoma with deterioration in visual function. Three weeks later, the patient had a rise in intraocular pressure and a scleral ectasia on the sclerectomy. The eye showed an area of scleral ectasia in the bleb as well as iris adhesion. Partial resection of the bleb after iris detachment led to poor anatomic and IOP results. The indications for deep sclerectomy must be carefully considered, especially in patients at a young age with this type of glaucoma.
J Cataract Refract Surg 2000 May
PMID:Scleral ectasia as a complication of deep sclerectomy. 1083 14

Many infants with intrauterine growth retardation (IUGR) are screened for TORCH infections. The yield and costs of such a practice may not be justifiable. Medical charts of infants with IUGR who had a workup for toxoplasmosis, other (infections), rubella, cytomegalovirus (infection), and herpes (simplex) (titer) (TORCH) infections were reviewed for the presence of clinical findings, laboratory and head ultrasound abnormalities associated with intrauterine infections. Maternal charts and reports of placental pathology were reviewed for identifying maternal illnesses and placental causes associated with IUGR. Seventy-five out of 182 infants (41%) with IUGR had a workup for TORCH infection. Maternal conditions associated with IUGR included: pregnancy-induced hypertension (19%), tobacco use (43%), alcohol abuse (21%), illicit drug use (24%), chronic hypertension, diabetic vasculopathy or collagen vascular disease (12%), and multiple gestation (3%). Placental pathology was available in 53/75 cases. Thirty-six of fifty-three (67%) placentae had abnormalities associated with IUGR: placental infarcts (22 of 36), vasculitis/villitis (15 of 36), placenta previa (1 of 36), abruptio placenta (2 of 36), and velamentous insertion of umbilical cord (1 of 36). Clinical findings among infants included hepatosplenomegaly, cataract or rash (1 of 75), thrombocytopenia and/or neutropenia and/or direct hyperbilirubinemia (11 of 75). Seven out of 75 infants had dysmorphic features. None of the infants (0 of 75) had positive IgM titers for toxoplasma, rubella, cytomegalovirus (CMV), or herpes simplex virus (HSV). No infants (0 of 43) had elevated total IgM titers; one infant (1 of 57) had a positive urine culture for CMV. One infant had evidence of calcifications on head ultrasound and a second infant had hydrocephalus (2 of 43). The costs associated with workup for TORCH infections among 75 infants included: TORCH titers determination: $17,816, total IgM titers: $1318, urine culture for CMV: $5734, and head ultrasound: $28,165. The yield of workup for TORCH infection among infants with IUGR is poor and does not justify the incurred costs.
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PMID:Yield and costs of screening growth-retarded infants for torch infections. 1101 37

Venous capillary wall in type II diabetic patients' conjunctiva was examined. The study was performed on conjunctiva fragments removed from diabetic patients during the operation of senile cataract. The fragments were fixed in Lillie's solution then studied by using optical microscopy with usual but histochemical stainings, too. Conjunctiva fragments removed from patients of the same age, being operated by senile cataract and one conjunctiva from ten years old patient were examined by using the same techniques as they could be compared. Computer determinations of the external and internal diameter of the same capillary in all three groups were performed. Venous capillary wall thickening by type IV collagen hyperproduction in all the aged patients was noted. This kind of thickening is more revealed in aged diabetic person. Type I-III collagen presence in the capillary wall of the diabetic patients was noted, too. The average value of the differential between the external and internal diameter was increased in the diabetic patients with diabetic retinopathy. Venous capillary wall thickening in the diabetic patients is due to the basal membrana both by means of the type IV collagen hyperproduction and presence of the I-III collagen, too.
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PMID:[Changes in the vascular wall in the conjunctiva of patients with diabetes mellitus]. 1102 Nov 6

We describe a new technique of nonpenetrating glaucoma surgery that uses the excimer laser to reduce the risk of perforating the trabeculo-Descemet's membrane. With this technique, the ablation is precise and homogeneous. A collagen device is sutured over the scleral bed to create an outflow pathway for aqueous humor drainage. After a superficial scleral flap is dissected with a diamond knife, the sclera, under direct visualization, is ablated with the excimer laser over Schlemm's canal until aqueous humor percolates through from the anterior chamber. A collagen device is placed over the sclera to allow the aqueous humor to flow from the anterior chamber through the trabeculo-Descemet's membrane. The preliminary results show a drop in intraocular pressure to the middle teens.
J Cataract Refract Surg 2001 Apr
PMID:Deep sclerectomy with a collagen implant using the excimer laser. 1131 14


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