Vibrational Spectroscopy and Cancer - Vibrational Spectroscopy for Tissue Analysis - page 85

argon laser was used. A spectrograph dispersed light scattered from arte-
rial tissue and a liquid nitrogen-cooled CCD detected the Raman spectra.
A total of 111 arterial fragments were scanned and Raman results were com-
pared with histopathology. An algorithm was modelled for tissue classifica-
tion into three categories: nonatherosclerotic (NA), noncalcified (NC), and
calcified (C) using Raman spectra. Spectra were randomly separated into
training and prospective groups. It was found that for the NA tissue, the
algorithm has sensitivity of 84% and 78% and specificity of 91% and 93% for
training and prospective groups, respectively. For NC tissue, the algorithm
has sensitivity of 88% and 90% and specificity of 88% and 83%. For the C
tissue, both sensitivity and specificity were at maximum 100% [136].
FTIR Spectroscopy for Cancer Grading
P. G. L. Andrus and R. D. Strickland used FTIR spectroscopy for cancer grad-
ing. Freeze-dried tissue samples from lymphoid tumours were studied. The
absorbance ratio of 1121 cm −1 /1020 cm −1 increased, along with the emergence
of an absorbance pulse at 1121 cm −1 , with increasing clinicopathological
grade of malignant lymphoma. This study proposed the above ratio as an
index of the cellular RNA/DNA ratio after subtraction of the overlapping
absorbances, if present, due to collagen or glycogen. Absorbance attributable
to collagen increased lymphoma grade and was greater in benign inflamma-
tory tumours than in low-grade lymphomas. It was also suggested that the
ratio trend may form the basis of a universal cancer grading parameter to
assist with cancer treatment decisions and may also be useful in the analysis
of cellular growth perturbation induced by drugs or other therapies [137].
G. J. Puppels et al. investigated carotenoids located in human lymphocyte
subpopulations (CD4+, CD8+, T-cellreceptor-γδ+, and CD19+), and natural
killer cells (CD16+) using Raman microspectroscopy. In CD4+ lympho-
cytes, a high concentration of carotenoids was found in the Gall body (about
10 −3 M). In other cell groups, except CD19+ groups, carotenoids appeared
to be concentrated in the Golgi complex (about 10 −4 M). The concentration
of carotenoids in CD19+ lymphocytes was found to be below the present
detection limit (about 10 −6 to 10 −5 M). The results provided new possibilities
for investigation of the mechanisms behind the suggested protective role of
carotenoids against the development of cancers [138].
J. L. Deng et al. carried out a study on the effect of alcohol on single human
red blood cells (RBCs) using near-infrared laser tweezers Raman spectros-
copy. A low-power diode laser at 785 nm was applied for the trapping of a liv-
ing cell and the excitation of its Raman spectrum. The denaturation process
of single RBCs in 20% alcohol solution was investigated by detecting the time
evolution of the Raman spectra at the single-cell level. The vitality of RBCs