Photographic and Spectroscopic Correlations of Human Cataracts

Abstract

Intracapsular cataracts obtained within 3 h after surgical extraction were photographed with the CCRG technique and immediately subjected to fluorescence spectroscopy followed by ³¹P- and ¹³C-nuclear magnetic resonance (NMR) spectroscopy. Fluorescence spectroscopy demonstrates an excellent correlation between nontryptophan fluorescence intensities and lens color. An interesting correlation was also observed between the degree of light scatter as determined by the 290-nm excitation peak for intrinsic lens tryptophan fluorescence and the CCRG (photographic) appearance of these cataractous lenses. Based on 100 cataracts analyzed, there is a strong correlation between this kind of light scattering measurement and the type and degree of lens opacification. A similar correlation is evident with the ³¹P-NMR organophosphate profiles in the lenses in which the sugar phosphate levels are elevated only in diabetic patients with cataracts (‘diabetic cataracts’). Aside from fluorescence and ³¹P-NMR spectroscopy, selected lenses were also incubated with 5.5 nM¹³C-glucose as soon as they were obtained, and the foregoing spectroscopy was performed, followed by ¹³C-NMR analyses to detect and monitor for sorbitol accumulation in young versus old normal lenses and in diabetic cataracts. These studies clearly demonstrate a direct correlation between nontryptophan-fluorescent chromophore levels, light scattering (determined by tryptophan excitation peaks), lens age and cataract type. In addition, the organophosphate profiles clearly delineate the diabetic cataracts, and the ¹³C-NMR spectra correlate well with the age-related decrease in aldose reductase activity

Autofluorescence of the crystalline lens in early and late onset diabetes.

“…17 The longer wavelength blue/green fluorogen may be derived from the shorter wavelength UV/ blue fluorogen, 8 19 in which case brunescence and the two fluorogens could share a common mechanism of production. It is possible that the pigmented species in nuclear cataract are related to the fluorogen responsible for the blue/green fluorescence seen in diabetic lenses.…”

Stability of Normal and Aging Lens Gamma Crystallins

“…The lenses were pooled by decade and a total of 12 lenses from the first two decades were employed as the 'young' protein source and 16 lenses from the 6th and 7th decade provided the source o f'old' protein materi al. The alpha, beta and gamma crystallins were sepa rated on Sephacryl 200 columns and the ensuing gam ma fraction was further purified and separated into the four major constituent gamma polypeptides by the modification of McDermott et al [32] of Slingsby and Miller's [33] method.…”

Fluorescence Polarization and Circular Dichroism Studies on Aging Human Lens Proteins

“…All of the lenses were evaluated for clarity by optical spectros copy [51] and were stored in the frozen state. Lenses were pooled by decades.…”