1,721,313 research outputs found
Editorial: Microbiological safety of foods
Full text linkThe management of food safety represents a global and transdisciplinary issue of great relevance for human health and crucial economic sectors [...]
Classifying Raman Spectra of Colon Cells by Principal Component Analysis—Linear Discriminant Analysis and Partial Least Squares—Linear Discriminant Analysis Methods
No full textColorectal cancer is one of the most commonly diagnosed cancers in developed countries. Although the gold-standard diagnosis technique is the histological analysis of colon biopsies, it is important to investigate different diagnostic tools because the microscope examination of stained tissues provides indications partially depending on the experience of the pathologist. This study reports a Raman-spectroscopy-based analysis of healthy and cancerous colon cells to detect biochemical differences at the subcellular level and discriminate the former from the latter. FHC and CaCo-2 cell lines were used to model healthy and cancerous cells, respectively. The comparison of the Raman spectra measured inside subcellular volumes including the nucleus (nucleus spectra) and excluding it (cytoplasm spectra), as well as principal component analysis and partial least squares analysis of these spectra, suggest that the differences between the spectra of healthy and cancerous cells are very small, and they mainly involve the different relative content of lipids and nucleic acid components. The relative intensity of lipid peaks is higher in the Raman spectra of healthy samples, while nucleic acid peaks show higher relative intensity in the spectra of cancer cells. Linear discriminant analysis of a few principal components and partial least squares components was used to estimate the classification accuracy of a set of Raman spectra measured inside nucleus and cytoplasm. Both methods are able to classify unknown cells with excellent accuracy (100% and 96%, respectively). The findings of this study confirm the general applicability of subcellular Raman analysis in clinical practice for diagnosis of cytological samples
Classification of Healthy and Cancer Colon Cells Grown on Glass Coverslip by Means of Fourier Transform Infrared Spectroscopy and Multivariate Methods
No full textFor several years, Fourier transform infrared (FTIR) microspectroscopy has been proving to be very promising for use in cytological diagnostics because of its capability of providing rapid
and label-free biochemical information about cell samples. The adoption of FTIR as a clinical tool has been slowed because of the poor compatibility with cells deposited on glass slides, commonly used in
clinical practice, because of the absorption of IR radiation by glassy materials in the 1000–1800 cm-1 spectral range. However, the possibility of also obtaining diagnostic information from the IR absorption
spectra in the 2700–3700 cm-1 range (including few peaks related to vibrational modes in cell lipids and proteins) has recently emerged. In this work, we investigate the use of the FTIR technique in the 2700–3700 cm-1 range for diagnostic purposes about human colon cells grown on glass coverslips. In fact, using the principal components analysis (PCA) technique, we are able to discriminate FTIR spectra of healthy cells from those of cancerous ones, mainly due to the larger relative lipid content in the former compared to the latter. In addition, principal component analysis-linear
discriminate analysis (PCA-LDA) and partial least square-discriminant analysis (PLS-DA) were used to build classification models for unknown FTIR spectra with optimal accuracy. These results
support the promotion of the translation of the FTIR technique as a complementary diagnostic tool in cytological routine practice
In Vitro Detection of Biochemical Effect in Human CaCo-2 Cell Line after Exposure to a Low Concentration of a Deltamethrin-Based Pesticide
No full textPesticide residues are chemicals frequently found in food as contaminants. Pesticides may have adverse health effects, particularly when the digestive tract is concerned, as a consequence of food ingestion. Deltamethrin is a pyrethroid pesticide widely used in various fields, such as agriculture, veterinary and in the household, so the ingestion of a small amount of this chemical may occasionally occur. To assess whether exposure to pesticide residues may have a biological effect at the intestinal level, it is primarily necessary to perform in vitro exposure experiments about cell lines models of the intestinal barrier at low concentrations of the chemical. In the present study, CaCo-2 cells were exposed to different concentrations of a Deltamethrin-based commercial pesticide, which was diluted in the cell medium. An MTT viability test indicated that the cytotoxic concentration value of the pesticide inside 1 mL of medium is between 10−6 and 10−5 mL. However, the analysis of Raman spectra found that biochemical changes occur inside cells exposed to a non-cytotoxic concentration of 10−6 mL of the pesticide inside 1 mL of the medium. Such changes involve mainly an increase in the ratio between the amount of lipid with respect to that of the protein components in the cell cytoplasm. The results obtained by Raman micro-spectroscopy were confirmed by fluorescence images obtained by using a fluorophore staining neutral lipids. Overall, the obtained results suggest that Raman micro-spectroscopy can be successfully used to monitor the cellular modifications due to exposure at low concentrations of pesticides, as those values that can be found inside food are residuals
Utilizzo della microspettroscopia Raman per valutare la sensitivit`a di cellule umane mammarie normali esposte ad un fascio di protoni a dosi cliniche.
No full textClassification of healthy and cancerous colon cells by Fourier transform infrared spectroscopy
No full textColorectal cancer is one of the most diagnosed types of cancer in developed countries. Current diagnostic methods are partly dependent on pathologist experience and laboratories instrumentation. In this study, we used Fourier Transform Infrared (FTIR) spectroscopy in transflection mode, combined with Principal Components Analysis followed by Linear Discriminant Analysis (PCA-LDA) and Partial Least Squares – Discriminant Analysis (PLS-DA), to build a classification algorithm to diagnose colon cancer in cell samples, based on absorption spectra measured in two spectral ranges of the mid-infrared spectrum. In particular, PCA technique highlights small biochemical differences between healthy and cancerous cells: these are related to the larger lipid content in the former compared with the latter and to the larger relative amount of protein and nucleic acid components in the cancerous cells compared with the healthy ones. Comparison of the classification accuracy of PCA-LDA and PLS-DA methods applied to FTIR spectra measured in the 1000–1800 cm−1 (low wavenumber range, LWR) and 2700–3700 cm−1 (high wavenumber range, HWR) remarks that both algorithms are able to classify hidden class FTIR spectra with excellent accuracy (100 %) in both spectral regions. This is a hopeful result for clinical translation of infrared spectroscopy: in fact, it makes reliable the predictions obtained using FTIR measurements carried out only in the HWR, in which the glass slides used in clinical laboratories are transparent to IR radiation
Discrimination of different breast cell lines on glass substrate by means of fourier transform infrared spectroscopy
No full textFourier transform infrared (FTIR) micro‐spectroscopy has been attracting the interest of many cytologists and histopathologists for several years. This is related to the possibility of FTIR translation in the clinical diagnostic field. In fact, FTIR spectra are able to detect changes in biochemical cellular components occurring when the cells pass to a pathological state. Recently, this interest has increased because it has been shown that FTIR spectra carried out just in the high wave-number spectral range (2500–4000 cm−1 ), where information mainly relating to lipids and proteins can be obtained, are able to discriminate cell lines related to different tissues. This possibility allows to perform IR absorption measurements of cellular samples deposited onto microscopy glass slides (widely used in the medical environment) which are transparent to IR radiation only for wave-number values larger than 2000 cm−1. For these reasons, we show that FTIR spectra in the 2800–3000 cm−1 spectral range can discriminate three different cell lines from breast tissue: a non‐malignant cell line (MCF10A), a non‐metastatic adenocarcinoma cell line (MCF7) and a metastatic adenocarci-noma cell line (MDA). All the cells were grown onto glass slides. The spectra were discriminated by means of a principal component analysis, according to the PC1 component, whose values have the opposite sign in the pairwise score plots. This result supports the wide studies that are being carried out to promote the translation of the FTIR technique in medical practice, as a complementary diagnostic tool
DNA-related modifications in a mixture of human lympho-monocyte exposed to radiofrequency fields and detected by raman microspectroscopy analysis
No full textHuman exposure to electromagnetic fields (EMFs) has risen considerably during the last decades, because of the industrial and technical development and the consequent increase of artificial EMFs sources. In particular, blood is largely involved in the environmental EMF exposure, because it is located everywhere in the human body. Lympho-monocyte cells are blood components that protect the human organism against infections. In this study, we investigate biochemical changes in lympho-monocyte cells extracted from human peripheral blood after exposure to EMFs at 1.8 GHz frequency and 200 V/m electric field strength for times ranging from 5 to 20 h inside a reverberation chamber. Some mixtures of cells, coming from many human subjects, were exposed and successively investigated by means of Raman micro-spectroscopy technique and principal components analysis. The spectral analysis was able to detect variations of the biochemical composition of the nucleus of exposed cells. Such modifications are mainly detectable as an intensity decrease of some DNA and nucleic acid Raman peaks with respect to the intensity of some protein peaks and they were most evident in the case of 20 h exposed samples. These results were in agreement with the increase of reactive oxygen species (ROS) production, observed in the exposed cells. Overall, the obtained results point out that EMFs exposure may induce modifications of the DNA in some blood cells of long-term exposed people
A comparison between FTIR spectra from HUKE and SH-SY5Y cell lines grown on different substrates
No full textIn recent years, Fourier Transform Infrared (FTIR) micro-spectroscopy has shown promising potential in medical diagnostics at the cellular level. In fact, FTIR spectra can provide information related to DNA, protein, and lipid content and how such a content changes when a pathological state arises. Most of these information is included in the so-called fingerprint region (1000–1800 cm−1), consisting of several spectral peaks related to vibrational modes occurring inside cellular components. Unfortunately, the slides commonly used in cytology (as the glass microscopy slides and coverslips) are opaque to IR radiation in the fingerprint region, whereas they are transparent for wavenumber values larger than 2000 cm−1, where few and broad spectral absorption bands, mainly due to lipids and proteins, are present. Nonetheless, here we show that FTIR spectra performed in the high wavenumber range 2750–3000 cm−1 can be used to discriminate two different types of cells, one from a normal cell line (Human Keratinocyte, HUKE) and the other from a cancer one (SH-SY5Y). The spectra are discriminated by means of their Principal Component Analysis, according to the PC1 component, and by means of ratiometric analysis, according to the ratio of the intensity of the peak at 2956 cm−1 and that of the peak at 2924 cm−1. The PC1 score values of the HUKE are statistically different from the PC1 score values of SH-SY5Y, whereas the intensity ratio results larger for SH-SY5Y than for HUKE cells. Such results occur for different substrates over which the cells have been grown, including the thick glass slides used for cytological analysis. This result is a further step toward the application of FTIR microspectroscopy in the cytological routine diagnosis
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