Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors report a case of Steinert's disease in a woman and discuss the endocrine profile of this disease after giving an account of the criteria of diagnosis. Disorders of gonad function are mild in women, primary testicular atrophy is very frequent in man with reduction in 17-ketosteroids and testosterone. Thyroid function was normal but, in a few cases, a low fixation curve was found (our case) corrected by TSH stimulation. The frequency of cataract emphasizes the interest of this sign for detection. Diabetes, associated with hyperinsulinism, seemed more frequent than in a population without Steinert's disease. The pathogenesis of these endocrine disorders appears secondary and is ill explained if one considers it as a single disease. Better knowledge, no doubt linked to progress in biochemistry of normal and myopathic muscle, will help to explain the pathogenesis.
Sem Hop 1977 Jan 23
PMID:[Endocrine aspects of Steinert's disease]. 18 36

Plasma membrane with its associated extrinsic proteins was isolated from normal and cataractous rat lenses by centrifugation of the total water insoluble fraction from homogenized lenses on a discontinuous sucrose gradient. Membrane, which we call "native" membrane, was recovered mainly from the 25/45% sucrose interface. Development of the experimental U18666A cataract resulted in plasma membrane shifting to higher density (the 50/55% sucrose fraction) and great increases in the urea soluble protein content of the lens. At early stages of cataract development, most of the increased urea soluble protein was membrane associated, presumably as extrinsic protein. With advancing cataract, most of the urea soluble protein appeared in an essentially membrane-free pellet fraction. The urea soluble protein associated with the cataract membrane was shown by combined IEF, SDS-PAGE, Western blotting, amino acid compositional analysis and protein sequence determinations to be mainly composed of modified alpha- and beta-crystallins. Alpha A-crystallin truncated by not more than 27 residues from the carboxyl terminus plus beta b1 crystallin truncated by 49 residues from the amino terminus were conclusively identified. In addition to beta b1, a population of six alpha-crystallin derived polypeptides were specifically enriched in the cataract membrane fraction. Four of these six alpha-crystallins appear to be truncated from their carboxyl terminus, a modification which should have increased their hydrophobicity. The pellet fraction, which accumulated in the lens nucleus as the cataract advanced, was enriched in urea soluble gamma-crystallin derived polypeptides. We suggest that protein insolubilization in this experimental cataract involves the selective and tight association of principally modified alpha-crystallins to the fiber cell plasma membrane.
 ...
PMID:Selective association of crystallins with lens 'native' membrane during dynamic cataractogenesis. 142 24

The composition and origin of the urea soluble polypeptides which accumulate in the U18666A rat-cataract were studied. Chromatography on Sephacryl S-200 in 7.2 M urea separated the USP into 19-20 and 22-26 kDa enriched fractions. The polypeptide composition of these fractions was probed by immunoblotting of IEF and 2-D electrophoresis gels. The cataract USP largely focused at pHs comparable to alpha- and beta-crystallins. Immunoblotting of 2-D gels showed the USP to be composed predominantly of alpha- and beta-derived crystallins; little gamma-polypeptide was detected in the gels. Some of the insoluble alpha-crystallin appeared to be degraded. Changes in the lens WSP which accompanied the increase in USP were also measured. WSP decreased more than USP increased. Decreases in soluble high molecular weight proteins (alpha- plus beta-crystallins) and medium molecular weight proteins (beta-crystallins) were calculated which together could entirely account for the increased USP. An unexpected decrease in the lens soluble low molecular weight proteins (gamma-crystallins) appeared largely due to the selective leakage of gammas from the lens. The protein content of the ocular humors from eyes with cataracts increased 4 fold and contained polypeptides that focused on IEF like gamma-light crystallin and reacted with the gamma-crystallin antiserum. The cause of the protein insolubilization in the U18666A cataract is unknown but could be partially due to increased aggregation of alpha-crystallins secondary to loss of gamma-crystallins from the lens.
 ...
PMID:On the composition and origin of the urea-soluble polypeptides of the U18666A cataract. 224 43

Because of minimal or no turnover, lens proteins are subjected to substantial post-translational modifications which in turn disrupt lens architecture and change the optical properties leading to senile cataract formation. Progressive glycation is believed to have the potential to initiate the changes that are conducive to lens opacification. Fisher 344 rats were systematically followed from juvenile to older and aged phases of their life to study the relationship between lens glycation and high molecular weight (HMW) aggregate formation as well as quantitative and qualitative changes in lens crystallins. Levels of glycated proteins were quantified by affinity chromatography. Changes in lens crystallin composition and HMW aggregate formation were monitored by molecular sieve HPLC, further confirmed by SDS-PAGE and IEF techniques. As the age advances HMW and insoluble proteins increase with a concomitant disappearance of gamma-crystallins from soluble fraction. This disappearance of gamma-crystallins coincided with increased glycation (approximately 2-fold higher in insoluble fraction) and decreased sulfhydryl groups from soluble fraction. It appears that lens protein glycation, disappearance of gamma-crystallins and sulfhydryls from soluble fraction and increase of insoluble fraction and HMW aggregate are interrelated.
 ...
PMID:Lens protein composition, glycation and high molecular weight aggregation in aging rats. 365 42

Two cases of Rothmund-Thomson syndrome in siblings are described. The elder patient, whose case was best documented and who was followed for several years, had the characteristic skin changes of poikiloderma congenitale with small stature and mental deficiency. Upon ophthalmologic examination, this patient was shown to have bilateral glaucoma which was treated surgically, while the cataract typically found in Rothmund-Thomson syndrome was lacking. Primary hypogonadism was confirmed by endocrinologic investigations; anterior pituitary hormones were normally released. With reference to this observation differential diagnosis is discussed; the medical literature is reviewed.
Sem Hop 1983 Dec 22
PMID:[Rothmund-Thompson syndrome with glaucoma. Endocrine study]. 631 63

A specific reagent DACM [N-(7-Dimethylamino-4-methyl-3-coumarinyl)maleimide] is used to study the -SH groups in lens proteins of normal and galactose cataractous rats. DACM when reacts readily with -SH groups form strong fluorescent adducts. The two -dimensional electrophoresis with DACM pre-labeled proteins is a simple and sensitive method for detecting -SH groups of protein subunit. In the present study, based on IEF/SDS-PAGE electrophoretically characterized soluble crystallins, describes specific changes in -SH groups of protein subunit during the development of galactose cataract. The contents of -SH groups of crystallins are progressively decreased in cataractous (5+) lens, the reduction of -SH content in alpha- and beta- crystallin protein subunits of the normal and cataractous lens proteins is also noticeable.
 ...
PMID:Assessment of sulfhydryl group in individual rat lens protein subunits during galactose cataract development. 784 79