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Intact Lenses (intact + lense)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

The role of mitochondria, cytochrome c and caspase-9 in embryonic lens fibre cell denucleation

JOURNAL OF ANATOMY, Issue 2 2002
E. J. Sanders
Abstract During the differentiation of secondary lens fibre cells from the lens epithelium, the fibre cells lose all of their cytoplasmic organelles as well as their nuclei. The fibre cells, containing crystallins, which confer optical clarity, then persist in the adult lens. The process of denucleation of these cells has been likened to an apoptotic event which is not followed by the plasma membrane changes that are characteristic of apoptosis. We have examined the expression and subcellular translocation of molecules of the apoptotic cascade in differentiating lens epithelial cells in culture. In this culture system, the epithelial cells differentiate into lentoids composed of lens fibre cells. We find that caspase-9, which is expressed and activated before embryonic day 12 in intact lenses, is localized in the cytosol outside mitochondria in non-differentiating cultured cells. In lentoid cells, caspase-9 migrates into mitochondria after the latter undergo a membrane permeability transition that is characteristic of apoptotic cells. At the same time, caspase-9 co-localizes with cytochrome c in the cytosol. The cytochrome c is apparently released from the mitochondria in lentoid cells after the mitochondrial membrane permeability transition and during the period of nuclear shrinkage. Also during this time, the mitochondria aggregate around the degenerating nuclei. Cytochrome c disappears rapidly, while mitochondrial breakdown occurs approximately coincident with the disappearance of the nuclei, but mitochondrial remnants persist together with cytochrome c oxidase, which is a mitochondrial marker protein. Apaf-1, another cytosolic protein of the apoptotic cascade, also migrates to the permeabilized mitochondria and also co-localizes with caspase-9 and cytochrome c in the cytosol or mitochondria of denucleating cells, thus providing evidence for the formation of an ,apoptosome' in these cells, as in apoptotic cells. At no time did we observe the translocation of molecules between cytoplasmic compartments and the nucleus in differentiating lentoid cells. We suggest that the uncoupling of nuclear and membrane apoptotic events in these cells may be due to the early permeability changes in the mitochondria, resulting in the loss of mitochondrial signalling molecules, or to the failure of molecules to migrate to the nucleus in these cells, thus failing to activate nuclear-plasma membrane signalling pathways. [source]

Comparative 1H NMR studies of saturation transfer in copolymer gels and mouse lenses

NMR IN BIOMEDICINE, Issue 6 2010
Koji Nakamura
Abstract Saturation transfer in cross-linked copolymer gels and excised intact and perforating trauma-induced cataract mouse lenses (4- or 8-week-old) were studied using intermolecular cross-relaxation rates (1/TIS(H2O); 1/TIS), monitored with f2 -irradiation at ,8.79, ,4.00, and 7.13,ppm (,H2/2,,,,69,Hz). [1] The 1/TIS(7.13,ppm) vs dry weight [W (%)] profiles for hydrophilic copolymer gels were far steeper than those for hydrophobic copolymer gels, indicating the participation of an amount of bound water and a number of copolymer hydroxyl groups in the saturation transfer process. In contrast, the 1/TIS(,8.79,ppm) vs W (%) profiles exhibited little difference between the hydrophilic and hydrophobic copolymer gels, indicating the major participation of molecular rigidity, i.e. W (%) in the saturation transfer process. [2] The 1/TIS(7.13,ppm) values for cataractous mouse lenses were larger than those for intact lenses, indicating the formation of large, immobile lens protein associates or aggregates containing a sufficient amount of bound water for the saturation transfer. [3] The 1/TIS(7.13,ppm) vs W (%) profiles for the hydrophilic copolymer gels exhibited similar characteristics to the intact and cataractous mouse lenses with regard to the saturation transfer process. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Contributions of Mouse Genetic Background and Age on Anterior Lens Capsule Thickness

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 12 2008
Brian P. Danysh
Abstract Accurate lens capsule thickness measurements are necessary for studies investigating mechanical characteristics of the capsule. Confocal Z -axis imaging was used to measure the anterior lens capsule thickness of living intact lenses with minimal tissue manipulation. Measurements of the anterior capsule thickness is reported for the first time in young and old mice from four inbred strains, BALB/c, FVB/N, C57BL/6, and 129X1, and the outbred strain ICR. Our data demonstrates that the mouse anterior lens capsule continues to grow postnatally similar to that described in other mammals. It is also shown there is a significant difference in anterior lens capsule thickness between unrelated mouse strains, suggesting that capsule thickness is a quantitative trait shared by strains with common ancestry. Measurements, taken from other regions of FVB/N capsules revealed the anterior pole to be the thickest, followed by the equatorial region and posterior pole. In addition to mouse, anterior capsule measurements taken from intact cattle, rabbit, rat lenses, and human capsulotomy specimens correlated with the overall size of the animal. Anat Rec, 2008. © 2008 Wiley-Liss, Inc. [source]

Biochemical changes in selenite cataract model measured by high-resolution MAS 1H NMR spectroscopy

ACTA OPHTHALMOLOGICA, Issue 5 2006
Miroslav Fris
Abstract. Purpose:, To correlate certain levels of lens opacification with high-resolution magic-angle spinning proton nuclear magnetic resonance (HR-MAS 1H NMR) spectroscopy analysis of the biochemical changes in rat lenses in a selenite cataract model. Methods:, Selenite cataract was induced by injecting 13-day-old Sprague-Dawley rat pups with a single subcutaneous dose of sodium selenite (3.28 mg/kg in 0.9% sodium chloride solution). Lens opacification was observed using a photographic slit-lamp microscope at selected time-points 3, 6 and 9 days after selenite injection and was then graded (levels 0, 1 and 2). The animals were killed after the slit-lamp microscopy, lenses were removed and HR-MAS 1H NMR spectra from intact lenses were obtained. Relative changes in metabolite concentrations were determined after comparison with matched lenses from untreated animals. Results:, Photographic slit-lamp microscopy revealed different stages of cataract in all animals treated with selenite. In the high quality HR-MAS 1H NMR spectra of the lenses, more than 30 different metabolites were identified in each lens. With the exception of taurine, the concentrations of all amino acids showed a significant increase (p < 0.05) in the second level of cataract. By contrast, glutathione (GSH), succinate and phosphocholine concentrations were significantly reduced. Conclusions:, For the first time, this study demonstrates the potential to correlate the level of lens opacification with the biochemical changes obtained with HR-MAS 1H NMR spectroscopy analysis in a selenite cataract model. [source]