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  • 1
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Age related changes in the lipid composition of human lens membranes have been documented and could be responsible for alterations in the function of lens membranes. To establish age related lipid composition-membrane structure relationships, we have examined spectroscopically the hydrocarbon chain structure of lipid membranes from human lens cortex and nucleus 0-95 years of age. Lipid membranes were extracted from human lenses using a monophasic methanolic extraction. The lipid composition of these membranes was determined by 31P-NMR and has already been reported. Fourier transform near-infrared Raman and Fourier transform infrared spectroscopies were used to determine human lens lipid structure. Lipid compositional differences were related to membrane structure. The frequency corresponding to the CH2 symmetric stretching band was found to increase with age in lipid samples from all regions of the lens. The frequency was used to estimate lipid hydrocarbon order. Lipid order was found to increase with age and was not significantly different for lipids extracted from the cortex compared to those from the nucleus. These results were confirmed qualitatively by comparing the height of the 2880 cm-1 band with the height of the 2850 cm-1 Raman band. Increased lipid order with age was also confirmed by the analysis of the C(SINGLE BOND)C stretching bands. Lipid hydrocarbon chain order increased linearly with increasing sphingomyelin content and decreased linearly with increasing phosphatidylcholine content. This trend, similar to that observed in other types of membranes, suggests that these two lipids may play a role in modulating lipid order. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 3 (1997), S. 113-120 
    ISSN: 1075-4261
    Keywords: anti-Stokes Raman spectroscopy ; urine ; quantitative analysis ; glucose ; raman spectroscopy ; medical applications ; metabolites ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Spontaneous anti-Stokes Raman spectra have been measured for urine to which glucose, acetone, or urea was added artificially, for urine including glucose, acetone, and urea simultaneously, and for urine of diabetics. The anti-Stokes Raman spectra obtained are all free from the interference from fluorescence and show a high signal-to-noise ratio. In the present system both Raman scattering from a sample and the reference beam from a laser are introduced into a monochromator simultaneously, making precise measurements of Raman intensities possible. The concentration of glucose, acetone, or urea in urine which includes one particular component artificially has been determined by the intensity of an anti-Stokes Raman band at 1130, 789, or 1016 cm-1, respectively. The correlation coefficient (R) between the concentration of glucose, acetone, or urea and the Raman intensity has been calculated to be 0.997, 0.96, and 0.97, respectively. The concentrations of glucose, acetone, and urea in urine including the three components simultaneously have also been determined by the intensities of the three bands. In this case, the R values have been found to be 0.92, 0.95, and 0.93 for glucose, acetone, and urea, respectively. In addition, the concentration of glucose in urine of the diabetics has been determined by the present anti-Stokes Raman system. © 1997 John Wiley & Sons, Inc. Biospect 3: 113-120, 1997
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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