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 effects of lactational mirex exposure on postnatal lens cation balance, lens growth and histology were examined in this study. Pregnant Long Evans rats were allowed to give birth, and litters were culled to eight individuals. Dams were intubated with 10 mg kg-1 day-1 mirex on days 1-4 postpartum. Pups were killed at 6-14 days of age, and lenses were removed, examined for opacities, weighed, and assayed for K+ and Na+ concentrations. Cataracts occurred in 71.0% of all treated litters and 58.1% of all treated individuals. Histologically, lenses from treated pups showed anterior and posterior cortical vacuoles by 8 days of age, greatly swollen lens fibers by 10 days of age, and areas of cell degeneration by 12-14 days of age. Lens K+:Na+ ratios were lower in treated groups on days 8-14 after birth, in both clear and cataractous lenses, and cataractous lenses were significantly higher in water content. Lens:eye weight ratios were not affected. The results of this study indicate that mirex-induced postnatal cataracts are due to lens degeneration subsequent to fiber cells swelling.
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PMID:Postnatal mirex cataractogenesis in rats: lens cation balance, growth and histology. 651 95

The effects of mirex on growth, histology, and K+ and Na+ concentrations of the fetal lens are examined. Pregnant Long-Evans rats were intubated with 6 mg/kg/day mirex in peanut oil on days 8-15 of gestation. Control dams received pure peanut oil. Fetuses were removed on days 18-21 and rated for extent of lens opacification and degree of edema. Lenses were removed, weighed, and assayed for K+ and Na+. Selected eyes were examined histologically. Cataracts were found in 49.6% of live treated fetuses on day 20, and the incidence and severity of cataracts were both correlated with the degree of fetal edema. Lens weights were reduced in treated litters whether or not cataracts occurred, but the reduction in cataractous lenses was greater. Sodium tended to be elevated and K+ reduced in lenses from treated fetuses, and the K+/Na+ ratio was significantly reduced in all treated groups. Histologically, treated lenses had swollen fibers on day 18 and areas of apparent cell breakdown by day 20. The swollen lens fibers, reduced K+/Na+ ratios and the correlation with edema suggest that fetal cataracts induced by mirex may be due to lens fiber cell breakdown subsequent to osmotic swelling.
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PMID:Mirex-induced fetal cataracts: lens growth, histology and cation balance, and relationship to edema. 687 57

We examined the difference in response to different degrees of injury in the mouse lens. The anterior side of the lens was pricked through the cornea by a microsyringe with a 31-gauge needle or an ordinary needle. The location of the needle tip was mostly marked with Evans' blue (EB) stain. At least three types of responses were recognizable. The first was a recovery type in which the wound was healed by an epithelial reaction. EB was localized at the superficial zone of the anterior cortex. The second was a type in which the change within the lens was stationary after forming a spherical body with a slightly smaller diameter than that of the entire lens. EB was observed in the intermediate zone of the anterior cortex. The third was a rapid progressive type of cataract which caused lens opacity within 3 days. The trace of the needle tip was observed around the perinuclear zone. These results suggest that the cortex of the mouse lens consists of three zones which may be functionally different around the lens nucleus: superficial, intermediate and perinuclear zones.
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PMID:Response of mouse lens to central needle injury. 809 Apr 35

The human RH locus appears to consist of two structural genes, D and CE, which map on the short arm p34-36 of chromosome 1 and specify a most complex system of blood-group genetic polymorphisms. Here we describe a family study of the Evans (also known as "D..") phenotype, a codominant trait associated with both qualitative and quantitative changes in D-antigen expression. A cataract-causing mutation was also inherited in this family and was apparently cotransmitted with Evans, suggesting a chromosomal linkage of these two otherwise unrelated traits. Southern blot analysis and allele-specific PCR showed the linkage of Evans with a SphI RFLP marker and the presence of a hybrid gene in the RH locus. To delineate the pattern of gene expression, the composition and structure of Rh-polypeptide transcripts were characterized by reverse transcriptase-PCR and nucleotide sequencing. This resulted in the identification of a novel Rh transcript expressed only in the Evans-positive erythroid cells. Sequence analysis showed that the transcript maintained a normal open reading frame but occurred as a CE-D-CE composite in which exons 2-6 of the CE gene were replaced by the homologous counterpart of the D gene. This hybrid gene was predicted to encode a CE-D-CE fusion protein whose surface expression correlates with the Evans phenotype. The mode and consequence of such a recombination event suggest the occurrence, in the RH locus, of a segmental DNA transfer via the mechanism of gene conversion.
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PMID:Genetic recombination at the human RH locus: a family study of the red-cell Evans phenotype reveals a transfer of exons 2-6 from the RHD to the RHCE gene. 880 97

The relationship between the polyol pathway and sugar cataracts has been studied extensively using streptozotocin-induced diabetic rats and galactose fed rats as animal models for insulin-dependent diabetes mellitus (IDDM). In these models, sugar cataracts progress quickly, leading to rapid lenticular polyol accumulation in the early stages of cataract formation. In 1992, a new animal model of non-insulin-dependent diabetes mellitus (NIDDM), the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, was established. In the present study, we examined both biochemical and morphological changes in the lenses of the OLETF rats to determine whether these changes reflect those associated with diabetic cataract formation and to clarify their relationship with the polyol pathway. For the biochemical analysis, we measured the enzyme activity of aldose reductase (AR) and sorbitol dehydrogenase (SDH) and the sorbitol levels using 20, 40 and 60 week old OLETF or control Long-Evans Tokushima Otsuka (LETO) rats. Enzyme activities of AR and SDH, which were lower in 20 week old OLETF rats than in LETO rats, were increased in 60 week old OLETF rats. The lenticular sorbitol level of the OLETF rats was similar to the control level at 20 weeks of age, but it was markedly increased at 40 weeks of age, and slightly decreased at 60 weeks of age compared with rats at 40 weeks but not compared with controls. Slight lens fiber swelling was observed in the anterior and/or posterior subcapsular regions of 40 week old OLETF rats, accompanying elevated sorbitol level and slightly increased SDH activity in the lens. Swelling and liquefaction of lens fibers were observed in the subcapsular and supranuclear region of 60 week old OLETF rats, as well as decreased lenticular sorbitol, and markedly increased SDH activity compared with rats at 40 weeks. AR activity was also increased causing the elevation of sorbitol in lenses of OLETF rats during the early stages of cataract formation. Despite differences in the etiology of diabetes mellitus, the strain of rat and the rate of disease progression in the OLETF rat model compared with other diabetic models, the present results support the theory that the polyol pathway via AR is a factor in the development of sugar cataracts.
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PMID:Biochemical and morphological changes during development of sugar cataract in Otsuka Long-Evans Tokushima fatty (OLETF) rat. 1152 Jan 12