Anatomy of the Experimental ‘Hypoglycemic’ Cataract in the Rat Lens

Greiner, Jack V.; Chylack, L. T.

doi:10.1159/000264808

Cited by 6 publications

(2 citation statements)

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“…Both by electron microscopy and light microscopy, with the fluorescent antibody technique, regions of the lens are found in which the plasma membrane has disintegrated In. these regions of disruption; there are amorphous pools of material, globular structures, and multilaminar structures (1)(2)(3)(4)(5)(6)(7)(8). Some of these structures can be stained with an antiserum to the 43,000-dalton extrinsic membrane protein (9).…”

mentioning

confidence: 99%

Biochemical evidence for membrane disintegration in human cataracts.

Garner¹,

Roy²,

Rosenfeld³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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Biochemical evidence is presented for the disintegration of the lens fiber plasma membrane in human cataracts. The intrinsic membrane proteins are found in both the water-soluble and water-insoluble nonmembrane fractions of the cataract lens but not in the normal tissue. Furthermore, in contrast to the normal lens, not all of the lipid found in the cataractous lens is isolated with the membrane fraction. In cataracts, both the membrane and membrane fragments are involved in covalent high molecular weight aggregates with an extrinsic membrane protein (43,000 daltons) and a cytoplasmic protein (y-crystallin).Studies of the structure of human senile cataracts have demonstrated a disappearance of normal fiber structure in the opaque region of the tissue. Both by electron microscopy and light microscopy, with the fluorescent antibody technique, regions of the lens are found in which the plasma membrane has disintegrated In. these regions of disruption; there are amorphous pools of material, globular structures, and multilaminar structures (1-8). Some of these structures can be stained with an antiserum to the 43,000-dalton extrinsic membrane protein (9). These disorganized areas probably contribute to the lightscattering characteristics observed in cataractogenesis. Although the morphological studies clearly suggest a breakdown of fiber structure, no convincing biochemical data to support such observations have been reported.Investigation of the biochemical changes in senile cataracts indicates a rapid increase of water-insoluble material at the expense of the water-soluble fraction (10-12). The acceleration in the generation of the insoluble fraction appears to be primarily due to the formation of new types of protein aggregates.A major component of the water-insoluble fraction of cataracts is the high molecular weight disulfide-linked (high Mr S-S) aggregates (13). These aggregates are present only in the cataractous lens and reflect the oxidative stress to which the tissue is subjected. Starting with oxidation at the membrane of the older normal lens, the oxidation spreads to cytoplasmic components with the formation of opacity (14). Methionine and other amino acids besides cysteine are involved. The high Mr S-S aggregates have been shown to-contain the 43,000-dalton extrinsic rhembrane protein (15). It has been suggested that such polypeptides may act as nucleation sites on the membrane for formation of high Mr S-S aggregates.Immunochemical and biochemical evidence is presented indicating that the plasma membrane disintegrates in senile cats aracts. This disrupted, plasma membrane is shown by immunochemical means to be associated with the high Mr S-S aggregates and with aggregates that cannot be dissociated by reduction and alkylation. These unusual aggregates, which are present in both the membrane and water-insoluble nonmembrane fractions of the cataractous lens, also appear to contain an appreciable amount of y-crystallin. MATERIALS AND METHODSNormal and cataractous human lenses were usually obtained ...

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mentioning

confidence: 99%

Biochemical evidence for membrane disintegration in human cataracts.

Garner¹,

Roy²,

Rosenfeld³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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“…1969;von Sallmann, 1957;Shinohara et al, 1978;Unakar et al, 1977]; coarse granules [Hamai et al, 1974;Leim-the et al, 1975;Philipson, 1973;Unakar et al, 1978] or disrupted membranes / Dilley et al, 1975;Eshaghian et al, 1978Gorthy, 1978Greiner and Chylack, 1976;Matsuto, 1973;Philipson. 1973;Unakar et al, 1978;Creighton et al, 1978], While such extensive cytological damage certainly contributes to light scattering in cataractous lenses, it is likely that these changes are advanced and irreversible alterations of lens cell structure.…”

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confidence: 99%

Scanning Electron Microscopy of Opaque and Transparent States in Reversible Calf Lens Cataracts

1980

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The microstructure of transparent and opaque calf lenses was studied using scanning electron microscopy. Cells in opaque lenses are very similar to cells in transparent lenses. This demonstrates that opacification does not require major changes in the structure or relative arrangement of the lens cells. We have, however, observed numerous, characteristic flat patches on the membrane surfaces of cells in opaque lenses. We also used laser diffraction and measurement of light transmittance to establish that glutaraldehyde fixation does not alter the optical properties or the cellular organization of the lens tissue.

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Spontaneous cataract in nude athymic mice: Ultrastructural analysis

Hazlett

Bradley

1978

Experimental Eye Research

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Anatomy of the Experimental ‘Hypoglycemic’ Cataract in the Rat Lens

Cited by 6 publications

References 1 publication

Biochemical evidence for membrane disintegration in human cataracts.

Biochemical evidence for membrane disintegration in human cataracts.

Scanning Electron Microscopy of Opaque and Transparent States in Reversible Calf Lens Cataracts

Spontaneous cataract in nude athymic mice: Ultrastructural analysis

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