Calcium content and distribution in human cataract

Hightower, Kenneth R.; Reddy, Venkat N.

doi:10.1016/0014-4835(82)90087-2

Cited by 61 publications

(32 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both hypercalcaemia and hypocalcaemia are well described causes of cataract (Brooks, 1975;Clark, Mengel, Bagg & Benedek, 1980;Hightower & Reddy, 1982a; Duncan & Bushell, 1976;Delamere & Paterson, 1981;Duke-Elder, 1969). Calcium has also been shown to control membrane permeability (Jacob & Duncan, 1981 b) and to be an essential component ofthe healing-over process in damaged lenses (Bernardini, Peracchia & Venosa, 1981).…”

Section: Introductionmentioning

confidence: 99%

Raised intracellular free calcium within the lens causes opacification and cellular uncoupling in the frog.

Jacob¹

1983

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Ion-sensitive micro-electrodes were used to measure the levels of intracellular free Ca2+ within the intact amphibian lens. The free [Ca2+] was found to constitute 0 4 % of the total lens calcium.2. The pCa measured at the anterior lens surface was found to be 6-59, while that at the posterior was 5 70. An 8-fold anterior/posterior Ca2+ gradient thus exists along the optical axis.3. The intracellular free Ca2+ could be manipulated by incubating the lens in high-Ca2+ or Ca2+-free EGTA Ringer solutions.4. Raising the intracellular free Ca2+ to 0-22 mm caused lens opacification and cellular uncoupling; the coupling ratio was reduced from 1 in control to 0-41 in high Ca2+

show abstract

Section: Introductionmentioning

confidence: 99%

Raised intracellular free calcium within the lens causes opacification and cellular uncoupling in the frog.

Jacob¹

1983

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…The intracellular calcium ion (Ca 2ϩ ) content is elevated in most cataractous lenses. 4,9,10) A decrease in plasma membrane Ca 2ϩ -ATPase, which regulates Ca 2ϩ levels in the lens, is one possible reason for the increase in Ca 2ϩ in cataract development. However, this possibility is very unlikely, because our previous report showed that Ca 2ϩ -ATPase in hereditary cataract model rat lenses increases with the progression of lens opacification.…”

mentioning

confidence: 99%

Inhibitors of Inducible Nitric Oxide Synthase Prevent Damage to Human Lens Epithelial Cells Induced by Interferon-Gamma and Lipopolysaccharide

Nagai

Liu

Fukuhata

et al. 2006

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

show abstract

“…3,25,26) In human senile cataracts, Dilsiz et al 27) reported that an ionic imbalance in lenses with increased Ca 2ϩ levels is related to cataract development. In this study, we show that the Ca 2ϩ levels in the lenses of these model rats increase with age (Table 2).…”

Section: Discussionmentioning

confidence: 99%

Comparison of the Mechanisms of Cataract Development Involving Differences in Ca2+ Regulation in Lenses among Three Hereditary Cataract Model Rats

Nagai

Ito

Takeuchi

et al. 2008

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

Cataracts are the major cause of blindness with an estimated 16 million people affected worldwide.1) The mechanism of cataract development is complicated and involves various factors including genetic factors, diabetes, smoking, nutrition, the cumulative effect of X-rays, ultraviolet irradiation, and alterations in both endocrine and enzymatic equilibria.2-7) Currently, radical oxygen species, especially those induced by UV rays in sunlight, are considered to be important in perturbing lens homeostasis. Following exposure to radical oxygen species, the calcium ion (Ca 2ϩ ) content in lens cells becomes elevated. 8,9) An elevated Ca 2ϩ content in the lens has been shown to activate calpain, a Ca 2ϩ -dependent protease. Furthermore, the degradation of lens proteins such as crystallin proteins results in an opaque lens. 8,9) Over the past several decades, there have been many studies exploring the mechanisms of cataract development.8) However, due to uncertainties regarding efficacy and safety, a potent anticataract drug for human cataracts has not yet been introduced.In studies to develop anti-cataract drugs, the selection of the experimental animal is very important. The UPL rat (UPLR), Shumiya cataract rat (SCR) and Ihara cataract rat (ICR/f; ICR) are hereditary cataractous strains, and it has been shown that these rats provide useful models in studies to develop anti-cataract drugs. Previous investigations have revealed that the proteolyses of some crystallins are significantly enhanced in UPLR, SCR and ICR lenses. [10][11][12][13][14] The Ca 2ϩ content in the cataractous lenses of UPLR, SCR and ICR are higher than in the lenses of Wistar rats, and autolytic products formed by calpain can also be detected in cataractous lenses.11,12,15,16) It is noteworthy that the cataracts formed in these rat models are not diabetic cataracts. Therefore, these rats have been used for studies to develop anti-cataract drugs. However, we recently reported that the increase in Ca 2ϩ content in the lenses of these rats is inhibited by an aminoguanidine, a selective inhibitor of inducible nitric oxide synthase (iNOS), and that the mechanism of Ca 2ϩ enhancement via iNOS among these rat models may differ. [17][18][19] Therefore, it is very important to clarify the mechanisms underlying the dysfunctions in Ca 2ϩ regulation in UPLR, SCR and ICR during cataract development.In the present study, we compare the mechanisms of the decrease in Ca 2ϩ outflow in the lenses of UPLR, SCR and ICR during cataract development. MATERIALS AND METHODSAnimals Cataractous UPLR, SCR and ICR were used in this study. The UPLR and ICR were provided by Meijo University (Aichi, Japan), and SCR was a gift from the Tokyo Metropolitan Institute of Gerontology (Tokyo, Japan). They were housed under standard conditions (12 h/d fluorescent light (07:00-19:00), 25°C room temperature), and allowed free access to a commercial diet (CE-2, Clea Japan Inc., Tokyo, Japan) and water. All procedures were performed in accordance with the Association for Research in Vis...

show abstract

Calcium content and distribution in human cataract

Cited by 61 publications

References 6 publications

Raised intracellular free calcium within the lens causes opacification and cellular uncoupling in the frog.

Raised intracellular free calcium within the lens causes opacification and cellular uncoupling in the frog.

Inhibitors of Inducible Nitric Oxide Synthase Prevent Damage to Human Lens Epithelial Cells Induced by Interferon-Gamma and Lipopolysaccharide

Comparison of the Mechanisms of Cataract Development Involving Differences in Ca2+ Regulation in Lenses among Three Hereditary Cataract Model Rats

Contact Info

Product

Resources

About