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A Spector

Publications and source records attributed to A Spector.

190 records · Page 11Linked to original sources
PubMedDate not supplied

Immunofluorescent localization of two intrinsic membrane polypeptides in adult human lenses.

Two major intrinsic membrane polypeptides of molecular weights 22K and 26K have been isolated and antisera for each prepared against highly purified preparations. The lack of reactivity of these antibodies in several other tissues suggests that they are unique to the lens. These antisera were used for localization of these polypeptides in adult human lenses by indirect immunofluorescent staining. Neither of the polypeptides is found in the epithelial cells; however those cells commencing differentiation show some fluorescent staining. The elongating fiber cells of the bow region show cytoplasmic staining for both 22K and 26K. This may reflect their sites of synthesis. In this region the species of 22K studies showed no localization in the membrane; however, 26K is concentrated at the membrane as evidenced by the intense band of fluorescent staining in this region. In the lens inner cortical region, there is a loss of cytoplasmic staining and both polypeptides appear to be membrane bound. This redistribution of the membrane polypeptides occurring in the inner cortex is at the site of considerable lens fiber contour alterations.

Adolescent↗
PubMedDate not supplied

Sodium/potassium ATPase in normal and cataractous human lenses.

Na/K ATPase activity has been determined in normal and cataractous human lenses using labeled ATP as a substrate. The enzyme is distributed throughout the lens with approximately 1/3 of the total activity in the capsule-epithelium and 1/2 of the activity in the cortex. Furthermore, the activity of Na/K ATPase decreases with increasing age and this decrease occurs primarily in the inner nuclear region. In severe cataractous lenses, a marked decrease in the Na/K ATPase activity has been demonstrated in all parts of the lens, in contrast to immature cataracts, where the decrease in the enzyme activity occurs primarily in the cortical and nuclear regions.

Animals↗
PubMedDate not supplied

Oxidation and aspects of ocular pathology.

Hydrogen peroxide (H2O2), a relatively stable oxidant, is present at low concentrations in the normal eye and is found at elevated concentrations in some patients with maturity-onset cataract. Recently, this laboratory has shown that H2O2 concentrations at levels only slightly above normal physiologic levels cause single-strand breaks in DNA within cultured lens epithelial cells obtained from calf lenses. It is hypothesized that such damage may contribute to the onset of cataract. The major enzyme which metabolizes H2O2 at the concentrations found in the eye is glutathione peroxidase. Since older individuals may have reduced activities of this enzyme and other enzymes involved in oxidative defense, this laboratory is synthesizing low-molecular-weight glutathione peroxidase mimics. It is possible that development of such compounds may improve the capacity of the lens to withstand oxidative stress in vitro.

Animals↗