Abstract
Cancer cells display high rates of glycolysis even under normoxia and mostly under hypoxia. Warburg proposed this effect of altered metabolism in cells more than 80 years ago. It is considered as a hallmark of cancer. Optical spectroscopy can be used to explore this effect. Pathophysiological studies indicate that mitochondria of cancer cells are enlarged and increased in number. Warburg observed that cancer cells tend to convert most glucose to lactate regardless of the presence of oxygen. Previous observations show increased lactate in breast cancer lines. The focus of this study is to investigate the relative content changes of lactate and mitochondria in human cancerous and normal breast tissue samples using optical spectroscopic techniques. The optical spectra were obtained from 30 cancerous and 25 normal breast tissue samples and five model components (Tryptophan, fat, collagen, lactate and mitochondrion) using fluorescence, Stokes shift and Raman spectroscopy. The basic biochemical component analysis model (BBCA) and a set of algorithm were used to analyze the spectra. Our analyses of fluorescence spectra showed a 14 percent increase in lactate content and 2.5 times increase in mitochondria number in cancerous breast tissue as compared with normal tissue. Our findings indicate that optical spectroscopic techniques may be used to understand Warburg effect. Lactate and mitochondrion content changes in tumors examined using optical spectroscopy may be used as a prognostic molecular marker in clinic applications. ZZ: [character removed]DT: J A new fiber-based imaging system has been incorporated into a modifie artificia eye for direct measurement of the thermal lensing effect induced by an infrared laser (1319 nm) to correlate changes in the visible wavefront to visual distortions observed by human subjects. The response of a visible beam, 632 nm, was observed with respect to various exposures of the infrared light under different power levels and exposure durations. Infrared irradiance levels between 0.57 and 4.56 W times cm -2 were used with exposure durations of 0.25, 0.50, 0.75, 1, and 2 seconds in order to observe the optimal level of radiant energy needed to bloom a visible beam at the retinal plane. Results show that deformation of the visible beam focused on the retina begins at irradiance levels of 2.28 W times cm -2 with significan blurring (10 times larger than the original size) at 3.80 W times cm -2 . A maximum visible beam size at the retina is achieved with exposure durations of 0.75 seconds, and no observable change was reported for longer exposure durations. These results strongly correlate to the previously determined threshold for visual distortion in human subjects using infrared lasers of 2.98 W times cm -2 . Based on these results, the visible wavefront will need to expand four times its original size in order to overcome any accommodation effects and induce an observable visual disruption in human subjects.