Monitoring of viral cancer progression using FTIR microscopy: A comparative study of intact cells and tissues

Predicting the Likelihood of Colorectal Cancer with Artificial Intelligence Tools Using Fourier Transform Infrared Signals Obtained from Tumor Samples

The early and accurate detection of colorectal cancer (CRC) significantly affects its prognosis and clinical management. However, current standard diagnostic procedures for CRC often lack sensitivity and specificity since most rely on visual examination. Hence, there is a need to develop more accurate methods for its diagnosis. Support vector machine (SVM) and feedforward neural network (FNN) models were designed using the Fourier transform infrared (FT-IR) spectral data of several colorectal tissues that were unanimously identified as either benign or malignant by different unrelated pathologists. The set of samples in which the pathologists had discordant readings were then analyzed using the AI models described above. Between the SVM and NN models, the NN model was able to outperform the SVM model based on their prediction confidence scores. Using the spectral data of the concordant samples as training set, the FNN was able to predict the histologically diagnosed malignant tissues (n = 118) at 59.9-99.9% confidence (average = 93.5%). Of the 118 samples, 84 (71.18%) were classified with an above average confidence score, 34 (28.81%) classified below the average confidence score, and none was misclassified. Moreover, it was able to correctly identify the histologically confirmed benign samples (n = 83) at 51.5-99.7% confidence (average = 91.64%). Of the 83 samples, 60 (72.29%) were classified with an above average confidence score, 22 (26.51%) classified below the average confidence score, and only 1 sample (1.20%) was misclassified. The study provides additional proof of the ability of attenuated total reflection (ATR) FT-IR enhanced by AI tools to predict the likelihood of CRC without dependence on morphological changes in tissues.

Artificial neural network in the discrimination of lung cancer based on infrared spectroscopy

Given the increasing prevalence of lung cancer worldwide, an auxiliary diagnostic method is needed alongside the microscopic examination of biopsy samples, which is dependent on the skills and experience of pathologists. Thus, this study aimed to advance lung cancer diagnosis by developing five (5) artificial neural network (NN) models that can discriminate malignant from benign samples based on infrared spectral data of lung tumors (n = 122; 56 malignant, 66 benign). NNs were benchmarked with classical machine learning (CML) models. Stratified 10-fold cross-validation was performed to evaluate the NN models, and the performance metrics-area under the curve (AUC), accuracy (ACC) positive predictive value (PPV), negative predictive value (NPV), specificity rate (SR), and recall rate (RR)-were averaged for comparison. All NNs were able to outperform the CML models, however, support vector machine is relatively comparable to NNs. Among the NNs, CNN performed best with an AUC of 92.28% ± 7.36%, ACC of 98.45% ± 1.72%, PPV of 96.62% ± 2.30%, NPV of 90.50% ± 11.92%, SR of 96.01% ± 3.09%, and RR of 89.21% ± 12.93%. In conclusion, NNs can be potentially used as a computational tool in lung cancer diagnosis based on infrared spectroscopy of lung tissues.

Detection of breast cancer by ATR-FTIR spectroscopy using artificial neural networks

In this study, three (3) neural networks (NN) were designed to discriminate between malignant (n = 78) and benign (n = 88) breast tumors using their respective attenuated total reflection Fourier transform infrared (ATR-FTIR) spectral data. A proposed NN-based sensitivity analysis was performed to determine the most significant IR regions that distinguished benign from malignant samples. The result of the NN-based sensitivity analysis was compared to the obtained results from FTIR visual peak identification. In training each NN models, a 10-fold cross validation was performed and the performance metrics-area under the curve (AUC), accuracy, positive predictive value (PPV), specificity rate (SR), negative predictive value (NPV), and recall rate (RR)-were averaged for comparison. The NN models were compared to six (6) machine learning models-logistic regression (LR), Naïve Bayes (NB), decision trees (DT), random forest (RF), support vector machine (SVM) and linear discriminant analysis (LDA)-for benchmarking. The NN models were able to outperform the LR, NB, DT, RF, and LDA for all metrics; while only surpassing the SVM in accuracy, NPV and SR. The best performance metric among the NN models was 90.48% ± 10.30% for AUC, 96.06% ± 7.07% for ACC, 92.18 ± 11.88% for PPV, 94.19 ± 10.57% for NPV, 89.04% ± 16.75% for SR, and 94.34% ± 10.54% for RR. Results from the proposed sensitivity analysis were consistent with the visual peak identification. However, unlike the FTIR visual peak identification method, the NN-based method identified the IR region associated with C-OH C-OH group carbohydrates as significant. IR regions associated with amino acids and amide proteins were also determined as possible sources of variability. In conclusion, results show that ATR-FTIR via NN is a potential diagnostic tool. This study also suggests a possible more specific method in determining relevant regions within a sample's spectrum using NN.

Breast cancer detection by ATR-FTIR spectroscopy of blood serum and multivariate data-analysis

Detection of breast cancer has particular importance for the diagnosis of cancer diseases. This is the most common type of cancer among women. Breast cancer is a malignant tumor of the glandular tissue of the breast. It is proposed to use infrared spectroscopy of blood serum as a simple and quick way to detect breast cancer. The paper presents the results of research using the methods of multivariate processing of IR spectra of human blood serum obtained by ATR-FTIR spectroscopy. The paper presents the results of research using the methods of multivariate processing of IR spectra of human blood serum obtained by ATR-FTIR spectroscopy. A sufficiently large sample of patients and healthy donors was diagnosed. Blood samples are examined from 66 patients who are clinically diagnosed with breast cancer and 80 healthy volunteers. A feature of the applied approach was a combination of the method of principal component analysis (PCA) and principal component regression (PCR) for processing the IR spectra of blood serum. The PCA method allows us to determine the spectral bands referring for the intensity differences between the control group and the patient group. Shown, that the range of 1306-1250cm^-1 in the IR spectrum of blood serum is diagnostically significant for breast cancer. This range corresponds to the vibrations of several functional groups of DNA and RNA, which play a key role in discrimination in breast cancer screening using ATR-FTIR spectroscopy. It is shown that the proposed method has advantages in ease of use for clinical diagnosis and gives good results for the identification of breast cancer. The values of sensitivity (92.3%) and specificity (87.1%) obtained using the PCR method are close to those of mammography and ultrasound. This indicates the possibility of using this method in real clinical laboratory diagnostics.

Advantages of infrared transflection micro spectroscopy and paraffin-embedded sample preparation for biological studies

Fourier-Transform Infrared micro-spectroscopy is an excellent method for biological analyses. In this paper, series metal coating films on ITO glass were prepared by the electrochemical method and the different thicknesses of paraffin embedding rat's brain tissue on the substrates were studied by IR micro-spetroscopy in attenuated total reflection (ATR) mode and transflection mode respectively. The Co-Ni-Cu alloy coating film with low cost is good reflection substrates for the IR analysis. The infrared microscopic transflection mode needs not to touch the sample at all and can get the IR spectra with higher signal to noise ratios. The Paraffin-embedding method allows tissues to be stored for a long time for re-analysis to ensure the traceability of the sample. Also it isolates the sample from the metal and avoids the interaction of biological tissue with the metals. The best thickness of the tissues is 4 μm.

Understanding the antimicrobial activity of selected disinfectants against methicillin-resistant Staphylococcus aureus (MRSA)

Disinfectants and biocidal products have been widely used to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections in homes and healthcare environments. Although disruption of cytoplasmic membrane integrity has been documented as the main bactericidal effect of biocides, little is known about the biochemical alterations induced by these chemical agents. In this study, we used Fourier transform infrared (FT-IR) spectroscopy and chemometric tools as an alternative non-destructive technique to determine the bactericidal effects of commonly used disinfectants against MRSA USA-300. FTIR spectroscopy permits a detailed characterization of bacterial reactivity, allowing an understanding of the fundamental mechanism of action involved in the interaction between bacteria and disinfectants. The disinfectants studied were ethanol 70% (N = 5), isopropanol (N = 5), sodium hypochlorite (N = 5), triclosan (N = 5) and triclocarban (N = 5). Results showed less than 5% colony forming units growth of MRSA treated with triclocarban and no growth in the other groups. Nearly 70,000 mid-infrared spectra from the five treatments and the two control (untreated; N = 4) groups of MRSA (bacteria grown in TSB and incubated at 37°C (Control I) / at ambient temperature (Control II), for 24h) were pre-processed and analyzed using principal component analysis followed by linear discriminant analysis (PCA-LDA). Clustering of strains of MRSA belonging to five treatments and the discrimination between each treatment and two control groups in MRSA (untreated) were investigated. PCA-LDA discriminatory frequencies suggested that ethanol-treated spectra are the most similar to isopropanol-treated spectra biochemically. Also reported here are the biochemical alterations in the structure of proteins, lipid membranes, and phosphate groups of MRSA produced by sodium hypochlorite, triclosan, and triclocarban treatments. These findings provide mechanistic information involved in the interaction between MRSA strains and hygiene products; thereby demonstrating the potential of spectroscopic analysis as an objective, robust, and label-free tool for evaluating the macromolecular changes involved in disinfectant-treated MRSA.

Investigation of gene expressions in differentiated cell derived bone marrow stem cells during bone morphogenetic protein-4 treatments with Fourier transform infrared spectroscopy

A model was set up to predict the differentiation patterns based on the data extracted from FTIR spectroscopy. For this reason, bone marrow stem cells (BMSCs) were differentiated to primordial germ cells (PGCs). Changes in cellular macromolecules in the time of 0, 24, 48, 72, and 96h of differentiation, as different steps of the differentiation procedure were investigated by using FTIR spectroscopy. Also, the expression of pluripotency (Oct-4, Nanog and c-Myc) and specific genes (Mvh, Stella and Fragilis) were investigated by real-time PCR. However, the expression of genes in five steps of differentiation was predicted by FTIR spectroscopy. FTIR spectra showed changes in the template of band intensities at different differentiation steps. There are increasing changes in the stepwise differentiation procedure for the ratio area of CH2, which is symmetric to CH2 asymmetric stretching. An ensemble of expert methods, including regression tree (RT), boosting algorithm (BA), and generalized regression neural network (GRNN), was the best method to predict the gene expression by FTIR spectroscopy. In conclusion, the model was able to distinguish the pattern of different steps from cell differentiation by using some useful features extracted from FTIR spectra.

Raman and infra-red microspectroscopy: towards quantitative evaluation for clinical research by ratiometric analysis

We demonstrate how ratioing spectral bands can circumvent experimental artefacts, and present a library of ratios from the biomedical literature.

Effect of Very Low Dose Fast Neutrons on the DNA of Rats' Peripheral Blood Mononuclear Cells and Leukocytes

The effect of very low dose fast neutrons on the chromatin and DNA of rats' peripheral blood mononuclear cells (PBMC) and leukocytes has been studied in the present work using Fourier transform infrared (FTIR) and single-cell gel electrophoresis (comet assay). Fourteen female Wistar rats were used; seven were irradiated with neutrons of 0.9 cGy (Am-Be, 0.02 cGy h(-1)), and seven others were used as control. Second derivative and curve fitting were used to analyze the FTIR spectra. In addition, hierarchical cluster analysis (HCA) was used to classify the group spectra. Meanwhile, the tail moment and percentage of DNA in the tail were used as indicators to sense the breaking and the level of damage in DNA. The analysis of FTIR spectra of the PBMC of the irradiated group revealed a marked increase in the area of phosphodiesters of nucleic acids and the area ratios of RNA/DNA and phosphodiesters/carbohydrates. A sharp significant increase and decrease in the areas of RNA and DNA ribose were recorded, respectively. In the irradiated group, leukocytes with different tail lengths were observed. The distributions of tail moments and the percentage of DNA in the tail of irradiated groups were heterogeneous. The mean value of the percentages of DNA in the tail at 0.5 h post-irradiation represented low-level damage in the DNA. Therefore, one can conclude that very low dose fast neutrons might cause changes in the DNA of PBMC at the submolecular level. It could cause low-level damage, double-strand break, and chromatin fragmentation of DNA of leukocytes.

Early detection of breast cancer using total biochemical analysis of peripheral blood components: a preliminary study

Background

Most of the blood tests aiming for breast cancer screening rely on quantification of a single or few biomarkers. The aim of this study was to evaluate the feasibility of detecting breast cancer by analyzing the total biochemical composition of plasma as well as peripheral blood mononuclear cells (PBMCs) using infrared spectroscopy.

Methods

Blood was collected from 29 patients with confirmed breast cancer and 30 controls with benign or no breast tumors, undergoing screening for breast cancer. PBMCs and plasma were isolated and dried on a zinc selenide slide and measured under a Fourier transform infrared (FTIR) microscope to obtain their infrared absorption spectra. Differences in the spectra of PBMCs and plasma between the groups were analyzed as well as the specific influence of the relevant pathological characteristics of the cancer patients.

Results

Several bands in the FTIR spectra of both blood components significantly distinguished patients with and without cancer. Employing feature extraction with quadratic discriminant analysis, a sensitivity of ~90 % and a specificity of ~80 % for breast cancer detection was achieved. These results were confirmed by Monte Carlo cross-validation. Further analysis of the cancer group revealed an influence of several clinical parameters, such as the involvement of lymph nodes, on the infrared spectra, with each blood component affected by different parameters.

Conclusion

The present preliminary study suggests that FTIR spectroscopy of PBMCs and plasma is a potentially feasible and efficient tool for the early detection of breast neoplasms. An important application of our study is the distinction between benign lesions (considered as part of the non-cancer group) and malignant tumors thus reducing false positive results at screening. Furthermore, the correlation of specific spectral changes with clinical parameters of cancer patients indicates for possible contribution to diagnosis and prognosis.

FTIR microspectroscopic characterization of Spitz nevi

In the last 10 years, few efforts have been carried out to apply vibrational spectroscopy in the study of dermal pathologies in order to characterize the most relevant spectral markers for distinguishing benign from cancerous lesions. Spitz nevi are a special group of benign melanocytic lesions, characterized by spindled and/or epithelioid nevomelanocytes, with peculiar clinical, dermoscopic and histopathological features. The "atypical forms" of Spitz nevi are among the commonest problems of differential diagnosis with the so-called "spitzoid melanomas". The clinical and histological criteria for discriminating these two entities are very subtle and often still quite subjective, and, in a significant percentage of cases, can lead to diagnostic pitfalls and inadequate therapies. Therefore, it is noteworthy to outline that the diagnosis of melanocytic lesions still represents a challenging problem and a continue matter of discussion. We exploited FTIR microspectroscopy to study the different kinds of spitzoid melanocytes, in order to define the most relevant spectral markers of each specimen and to achieve objective information on "borderline" histologically atypical lesions. In particular, the spectroscopic investigation was carried out on melanocytes deriving from normal skin (as a normal control), malignant melanoma and Spitz nevi. The presence of the characteristic bands of melanin was investigated, too.

Protective effects of desferrioxamine and deferiprone on the spleen tissue of aluminum intoxicated mice: A Fourier transform infrared spectroscopy study

The present study was designed to examine the protective effects of the chelating agents desferrioxamine (DFO) and deferiprone (DFP) in aluminum intoxicated spleen tissue of mice by Fourier transform infrared (FTIR) spectroscopy. The finding revealed the alterations on the major biochemical constituents, such as lipids, proteins, phosphodiester and nucleic acids of the spleen tissue of mice at molecular level. The significant decreased in the peak areas of asymmetric and symmetric mode of the phosphodiester groups from control to aluminum intoxicated, but improved it by DFP and DFO+DFP treatments respectively for nearer control value. The bands ratio at I1081/I1232 significantly decreased from control to aluminum, but enhanced it by DFP and DFO+DFP respectively. This result suggests that DFO and DFP are the phosphodiesterase inhibitor, recovered from chronic growth of diseases in the spleen. Amide I and amide II peak area values decreased from control to aluminum intoxicated spleen tissue, but treated with DFP and DFO+DFP significantly improved. This result suggests an alteration in the protein profile. The absence of Olefinic=CH stretching in aluminum intoxicated spleen suggests an altered lipid levels. Concentrations of trace elements were found by ICP-OES. Histopathological findings confirmed the biochemical observations of this study. The results of the FTIR study were found to be in agreement with biochemical studies and demonstrated that FTIR can be used successfully applied to toxicological studies at molecular level.

FTIR study of protective action of deferoxamine and deferiprone on the kidney tissues of aluminum loaded mice

The present study was designed to evaluate the FTIR spectra of the aluminum exposed kidney tissues and recovered by chelating agents DFO and DFP then showed significant alteration on the major biochemical constituents such as lipids, proteins and glycogen at molecular level. The significant increased in the peak area of glycogen from 0.006±0.001 to 0.187±0.032 may be the interruption of aluminum in the calcium metabolism and the reduced level of calcium. The peak area value of amide A significantly decreased from control (4.931±1.446) to aluminum (1.234±0.052), but improved by DFP and DFO+DFP from 2.658±0.153 to 3.252±0.070 respectively. Amide I and amide II peak area values also decreased from 1.690±0.133 to 0.811±0.192 and 1.158±0.050 to 0.489±0.047 but treated with DFP and DFO+DFP significantly improved. This result suggests an alteration in the protein profile. The absence of Olefinic=CH stretching band, C=O stretching of triglycerides and ring breathing mode in the DNA bases in aluminum exposure kidney suggests an altered lipid levels. Treated with DFP and DFO+DFP mice were considerably increased in lipid peroxidative markers. Further, assessed the activities of enzymatic antioxidants and measured the levels of nonenzymatic antioxidants. Concentrations of trace elements were found by ICP-OES. Histopathology of chelating agents treated kidney showed reduced renal damage in aluminum induced mice. Thus, histopathological findings confirmed the biochemical observations of this study. This results demonstrated that FTIR spectroscopy can be successfully applied to toxicological and biotoxicology studies.

Infrared (IR) spectral markers of bronchial epithelia in victims of fatal burns

Changes in the infrared spectra of bronchial epithelia in victims of fatal burns were investigated. The mechanism of spectral changes on the basis of cellular morphological changes was considered. The ability of spectral parameters to diagnose fatal burns was assessed. Ten cases of fatal burns and 20 control cases were selected. Their lung tissues were removed, and sections were cut and mounted on glass and barium fluoride slides. Spectra of polarized bronchial epithelia were obtained by microscopy based on their morphological changes. In the spectra, 16 major absorbance bands were evaluated to determine their ability to act as positive markers for exposure to fire. Compared with the control group, the bronchial epithelia of the fatal burn victims showed three spectral results. (1) The absorbance of 16 major bands from the spectra of polarized bronchial epithelia in fatal burn victims significantly increased. (2) For the same cell number, the absorbance at 2850, 2920, 2959, and 3084 cm(-1) decreased. (3) The degree of increased or decreased absorbance of bands is related to the degree of polarization. These spectral results suggest that there is a vital reaction induced by the inhalation of hot fumes that includes an increase in the number of bronchial epithelia and a polarization effect. Overall, Fourier transform infrared (FT-IR) microspectroscopy was shown to be a convenient and reliable method to provide objective spectral markers to assist the diagnosis of fatal burns by simultaneously monitoring several specific parameters, although these observations have yet to be applied at forensic scenes.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300cm(-1) increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A1172/A1126, A1456/A1403, and A2925/A2957 were significantly increased, whereas the A1652/A1541 ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737cm(-1) were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.

Screening of chemopreventive effect of naringenin-loaded nanoparticles in DMBA-induced hamster buccal pouch carcinogenesis by FT-IR spectroscopy

The aim of the present study is to investigate the chemopreventive effects of the prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) in modifying the functional, structural, and compositional changes at the molecular level during 7, 12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis by Fourier transform infrared (FT-IR) spectroscopy. The results revealed that a significant increase in the amount of proteins and nucleic acid contents and a decrease in the amount of lipids and glycogen contents are observed in DMBA-induced tumor tissues. In addition, in tumor tissues a decrease in lipid order and a significant increase in membrane dynamics were noticed. Further, the composition and secondary structure of proteins were found to be altered, which indicates some important structural alterations in the existing proteins and/or the expression of new types of proteins occurring under the tumor transformation. Furthermore, oral administration of free NAR and NARNPs significantly increased lipids and their order as well as increased the glycogen contents and decreased the levels of proteins and nucleic acid contents. On a comparative basis, NARNPs were found to have a more potent antitumor effect than free NAR in completely preventing the formation of squamous cell carcinoma and in improving the biochemical constituents to a normal range in DMBA-induced HBP carcinogenesis. The present study further shows a great potential of FT-IR spectroscopy as a complimentary tool for the screening of various anticancer drugs and follow-up, which may allow faster response to critical problems arising during treatment.

Oral cancer diagnostics based on infrared spectral markers and wax physisorption kinetics

Infrared microspectroscopy is an emerging approach for disease analysis owing to its capability for in situ chemical characterization of pathological processes. Synchrotron-based infrared microspectroscopy (SR-IMS) provides ultra-high spatial resolution for profiling biochemical events associated with disease progression. Spectral alterations were observed in cultured oral cells derived from healthy, precancerous, primary, and metastatic cancers. An innovative wax-physisorption-based kinetic FTIR imaging method for the detection of oral precancer and cancer was demonstrated successfully. The approach is based on determining the residual amount of paraffin wax (C(25)H(52)) or beeswax (C(46)H(92)O(2)) on a sample surface after xylene washing. This amount is used as a signpost of the degree of physisorption that altered during malignant transformation. The results of linear discriminant analysis (LDA) of oral cell lines indicated that the methylene (CH(2)) and methyl group (CH(3)) stretching vibrations in the range of 3,000-2,800 cm(-1) have the highest accuracy rate (89.6 %) to discriminate the healthy keratinocytes (NHOK) from cancer cells. The results of wax-physisorption-based FTIR imaging showed a stronger physisorption with beeswax in oral precancerous and cancer cells as compared with that of NHOK, which showed a strong capability with paraffin wax. The infrared kinetic study of oral cavity tissue showed a consistency in the wax physisorption of the cell lines. On the basis of our findings, these results show the potential use of wax-physisorption-based kinetic FTIR imaging for the early screening of oral cancer lesions and the chemical changes during oral carcinogenesis.

A label-free indicator for tumor cells based on the CH2-stretch ratio

In this paper, we assess the potential of a label-free infrared absorbance based measurement method for determination of the CH(2)-symmetric to CH(2)-antisymmetric stretch ratio, to aid in the detection of the presence of cancer cells and to differentiate between various cancer cells. For this study a normal epithelial kidney cell line, two carcinoma epithelial kidney cell lines, an adult primary human melanocyte cell line, and three human melanoma cell lines were investigated. For the measurements we used a self-designed IR sensor which has the potential to be further developed in a point-of-care instrument. To investigate the mechanism influencing the CH(2)-stretch ratio of mammalian cell membranes, a normal epithelial kidney cell line was exposed to the plasma membrane bound cholesterol reducing agent methyl-β-cyclodextrin. This methodology yielded statistically significant CH(2)-stretch ratio differences between the individual cell lines, normal and tumorous, of both epithelial kidney and melanocyte origin. Measurement results of normal epithelial kidney cells exposed to methyl-β-cyclodextrin indicate that an increase in the CH(2)-stretch ratio arises when there is a decrease in, or redistribution of, the membrane stabilizing agent cholesterol. This study proves that the proposed cell type discrimination method, based on the CH(2)-symmetric to CH(2)-antisymmetric stretch ratio, allows the discrimination between normal and tumor cells. In addition, the method shows high potential for improvement of staging of suspicious tissues.

Subcellular localization of early biochemical transformations in cancer-activated fibroblasts using infrared spectroscopic imaging

The tumor microenvironment, or stroma, is chemically and morphologically modified during carcinoma progression. The predominant cell type in the stroma, the fibroblast, maintains collagen properties in normal tissue and often transformed during tumor progression. Biochemical changes within fibroblasts upon initial cancer activation, however, are relatively poorly defined. Here, we hypothesized that Fourier transform infrared (FT-IR) spectroscopic imaging could potentially be employed to examine these early transformations. Further, we employ attenuated total reflectance (ATR) microscopy to characterize subcellular spectra and their changes upon transformation. We characterized fibroblast transitions upon stimulation with both a molecular agent and a carcinoma-mimicking cellular co-culture system. Changes were predominantly observed in the 1080 cm(-1) and 1224 cm(-1) peak absorbance, commonly associated with nucleic acids, as well as in the band at 2930 cm(-1) associated with the C-H stretching of proteins in the cytoplasmic compartment. In conclusion, biochemical changes in cancer-associated fibroblasts that express α-SMA are dominated by the cytoplasm, rather than the nucleus. This ensures that spectral changes are not associated with proliferation or cell cycle processes of the cells and the cells are undergoing a true phenotypic change denoted by protein modifications in the cell body.

Biochemical analysis and quantification of hematopoietic stem cells by infrared spectroscopy

Identification of hematopoietic stem cells (HSCs) in different stages of maturation is one of the major issues in stem cell research and bone marrow (BM) transplantation. Each stage of maturation of HSCs is characterized by a series of distinct glycoproteins present on the cell plasma membrane surface, named a cluster of differentiation (CD). Currently, complicated and expensive procedures based on CD expression are needed for identification and isolation of HSCs. This method is under dispute, since the correct markers' composition is not strictly clear, thus there is need for a better method for stem cell characterization. In the present study, Fourier transform infrared (FTIR) spectroscopy is employed as a novel optical method for identification and characterization of HSCs based on their entire biochemical features. FTIR spectral analysis of isolated mice HSCs reveals several spectral markers related to lipids, nucleic acids, and carbohydrates, which distinguish HSCs from BM cells. The unique "open" conformation of HSC DNA as identified by FTIR is exploited for HSCs quantification in the BM. The proposed method of FTIR spectroscopy for HSC identification and quantification can contribute to stem cell research and BM transplantation.