Udi Zelig

Diagnosis of Cell Death by Means of Infrared Spectroscopy

Fourier transform infrared (FTIR) spectroscopy has been established as a fast spectroscopic method for biochemical analysis of cells and tissues. In this research we aimed to investigate FTIRs utility for identifying and characterizing different modes of cell death, using leukemic cell lines as a model system. CCRF-CEM and U937 leukemia cells were treated with arabinoside and doxorubicin apoptosis inducers, as well as with potassium cyanide, saponin, freezing-thawing, and H(2)O(2) necrosis inducers. Cell death mode was determined by various gold standard biochemical methods in parallel with FTIR-microscope measurements. Both cell death modes exhibit large spectral changes in lipid absorbance during apoptosis and necrosis; however, these changes are similar and thus cannot be used to distinguish apoptosis from necrosis. In contrast to the above confounding factor, our results reveal that apoptosis and necrosis can still be distinguished by the degree of DNA opaqueness to infrared light. Moreover, these two cell death modes also can be differentiated by their infrared absorbance, which relates to the secondary structure of total cellular protein. In light of these findings, we conclude that, because of its capacity to monitor multiple biomolecular parameters, FTIR spectroscopy enables unambiguous and easy analysis of cell death modes and may be useful for biochemical and medical applications.

Can Fourier transform infrared spectroscopy at higher wavenumbers "mid IR… shed light on biomarkers for carcinogenesis in tissues?

Fourier transform infrared microspectroscopy (FTIR-MSP) has shown promise as a technique for detection of abnormal cell proliferation and premalignant conditions. In the present study, we investigate the absorbance in the sensitive wavenumber region between 2800 and 3000 cm(-1), which has been known to be due to the antisymmetric and symmetric stretching vibrations of CH2 and CH3 groups of proteins and lipids. We report common biomarkers from this region that distinguish between normal and malignant tissues and cell lines. Based on our findings, we propose that the wavenumber region around 2800 to 3000 cm(-1) in the FTIR spectra of cells and tissues could provide valuable scientific evidence at the onset of premalignancy and may be used for ex vivo and in vitro detection of carcinogenesis. To further examine the utility of these markers in cancer diagnosis and management, they are tested successfully in monitoring the changes occurring in leukemia patients during chemotherapy.

Detection of Cancer Using Advanced Computerized Analysis of Infrared Spectra of Peripheral Blood

We have developed a novel approach for detection of cancer based on biochemical analysis of peripheral blood plasma using Fourier transform infrared spectroscopy. This approach has proven to be quick, safe, minimal invasive, and effective. Our approach recognizes any signs of solid tumor presence, regardless of location in the body or cancer type by measuring a spectrum that gives information regarding the total molecular composition and structure of the peripheral blood samples. The analysis includes clinically relevant preprocessing and feature extraction with principal component analysis, and uses Fishers linear discriminant analysis to classify between cancer patients and healthy controls. We evaluated our method with leave-one-out cross validation and were able to establish sensitivity of 93.33%, specificity of 87.8%, and overall accuracy of 90.7%. Using our method for cancer detection should result in fewer unnecessary invasive procedures and yield fast detection of solid tumors.