The cell-cycle dependence of the FTIR spectra of myeloid leukemia (ML-1) cells: A step towards understanding the spectral differences observed in normal vs. neoplastic cells.
Item
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Title
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The cell-cycle dependence of the FTIR spectra of myeloid leukemia (ML-1) cells: A step towards understanding the spectral differences observed in normal vs. neoplastic cells.
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Identifier
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AAI9946144
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identifier
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9946144
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Creator
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Boydston-White, Susie Cliff.
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Contributor
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Adviser: Max Diem
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Date
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1999
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry | Biology, Cell | Engineering, Biomedical | Health Sciences, Oncology
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Abstract
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Previous FTIR spectroscopic studies of normal vs. neoplastic cells (and tissues) have shown differences in the absorption intensities and band-shapes, particularly in the nucleic acid (900--1200 cm-1 ) spectral region, that correlated with the existence of cancer. Further, studies of the mixtures of various proportions of RNA and DNA proved that these changes are due to the increased IR signals of DNA vs. RNA.;Using a relatively undifferentiated cell line (Myeloid Leukemia) separated into homogenous populations, based on the phase of the eukaryotic cell cycle, the cell-cycle-dependent FTIR spectral signatures were determined. Spectral Profiling that consists of deconvolving the nucleic acid region of the spectra into a minimum number of Gaussian component bands, optimizing the fit and plotting the areas of the Gaussians vs. frequency, was used to further analyze the spectra. The resulting "profile" of the spectra produced may be compared with other profiles.;The cell-cycle phases' profiles were compared with the profiles produced from the mixtures of proportions of RNA and DNA. It was found that the spectral features observed most often in neoplastic cells and tissues correlated to an increased proportion of DNA vs. RNA and were observed only in cells that were actively synthesizing DNA---cells in the S phase. Cells in the Gap phases (the G1 and G2 phases) yielded spectra that were superimposable on each other, on the spectra of normal cells (and tissues) and on the spectra of RNA/DNA mixtures that contain high RNA:DNA ratios.;Since the nuclei of G2-phase cells contain twice the DNA content of G1-phase cells, yet the nucleic acid peaks (1000 to 1150 cm-1) and the profile bands are identical in shape and relative intensities and the profile was found to be identical to the profile of pure RNA, we concluded that nuclear DNA is "invisible" to FTIR spectroscopy in all but the S phase of the cell cycle. Furthermore, we concluded that the spectral changes observed in neoplastic cells and tissues are not, necessarily, a "signature of cancer," but may simply represent a larger than expected proportion of cells in a sample in the S phase of the cell cycle.
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Type
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dissertation
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Source
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PQT Legacy Restricted.xlsx
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degree
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Ph.D.