Fourier transform infrared microspectroscopy as a diagnostic tool for distinguishing between normal and malignant human gastric tissue

Biomolecular alterations detected in multiple sclerosis skin fibroblasts using Fourier transform infrared spectroscopy

Multiple sclerosis (MS) is the leading cause of non-traumatic disability in young adults. New avenues are needed to help predict individuals at risk for developing MS and aid in diagnosis, prognosis, and outcome of therapeutic treatments. Previously, we showed that skin fibroblasts derived from patients with MS have altered signatures of cell stress and bioenergetics, which likely reflects changes in their protein, lipid, and biochemical profiles. Here, we used Fourier transform infrared (FTIR) spectroscopy to determine if the biochemical landscape of MS skin fibroblasts were altered when compared to age- and sex-matched controls (CTRL). More so, we sought to determine if FTIR spectroscopic signatures detected in MS skin fibroblasts are disease specific by comparing them to amyotrophic lateral sclerosis (ALS) skin fibroblasts. Spectral profiling of skin fibroblasts from MS individuals suggests significant alterations in lipid and protein organization and homeostasis, which may be affecting metabolic processes, cellular organization, and oxidation status. Sparse partial least squares-discriminant analysis of spectral profiles show that CTRL skin fibroblasts segregate well from diseased cells and that changes in MS and ALS may be unique. Differential changes in the spectral profile of CTRL, MS, and ALS cells support the development of FTIR spectroscopy to detect biomolecular modifications in patient-derived skin fibroblasts, which may eventually help establish novel peripheral biomarkers.

Single-cell infrared vibrational analysis by optical trapping mid-infrared photothermal microscopy

Single-cell analysis by means of vibrational spectroscopy combined with optical trapping is a reliable platform for unveiling cell-to-cell heterogeneities in vast populations. Although infrared (IR) vibrational spectroscopy provides rich molecular fingerprint information on biological samples in a label-free manner, its application with optical trapping has never been achieved due to weak gradient forces generated by the diffraction-limited focused IR beam and strong background of water absorption. Herein, we present single-cell IR vibrational analysis that incorporates mid-infrared photothermal (MIP) microscopy with optical trapping. Optically trapped single polymer particles and red blood cells (RBCs) in blood could be chemically identified owing to their IR vibrational fingerprints. This single-cell IR vibrational analysis further allowed us to probe the chemical heterogeneities of RBCs originating from the variation in the intracellular characteristics. Our demonstration paves the way for the IR vibrational analysis of single cells and chemical characterization in various fields.

High-sensitivity hyperspectral vibrational imaging of heart tissues by mid-infrared photothermal microscopy

Visualizing the spatial distribution of chemical compositions in biological tissues is of great importance to study fundamental biological processes and origin of diseases. Raman microscopy, one of the label-free vibrational imaging techniques, has been employed for chemical characterization of tissues. However, the low sensitivity of Raman spectroscopy often requires a long acquisition time of Raman measurement or a high laser power, or both, which prevents one from investigating large-area tissues in a nondestructive manner. In this work, we demonstrated chemical imaging of heart tissues using mid-infrared photothermal (MIP) microscopy that simultaneously achieves the high sensitivity benefited from IR absorption of molecules and the high spatial resolution down to a few micrometers. We successfully visualized the distributions of different biomolecules, including proteins, phosphate-including proteins, and lipids/carbohydrates/amino acids. Further, we experimentally compared MIP microscopy with Raman microscopy to evaluate the sensitivity and photodamage to tissues. We proved that MIP microscopy is a highly sensitive technique for obtaining vibrational information of molecules in a broad fingerprint region, thereby it could be employed for biological and diagnostic applications, such as live-tissue imaging.

Identification of hepatocellular carcinoma and paracancerous tissue based on the peak area in FTIR microspectroscopy

Hepatocellular carcinoma (HCC) is one of the most common primary hepatic malignancies across the world. The annual incidence and death rates have increased at the highest rate of all cancers in recent years. Surgical resection is a potentially curative option for solitary HCC or unilobar disease without evidence of metastases or vascular invasion. This study focuses on the molecular differences between the HCC foci and paracancerous tissues and provides some valuable biomarkers based on the vibrational spectrum. Fourier transform infrared (FTIR) spectroscopy is a non-invasive and qualitative and semi-quantitative analysis technique that has been widely applied for the identification of macromolecular changes in biological tissues. In this study, the FTIR spectra of the HCC foci and the paracancerous tissues were recorded separately, and ten areas under the absorption peaks of all the specimens were calculated. The result demonstrates that the areas of protein-related absorption peaks at 1398 cm^-1, 1548 cm^-1, 1654 cm^-1 and 3070 cm^-1 may be the key indicators of the two different regions. After coupling with the classification algorithms of k-nearest neighbor (KNN), random forest (RF) and support vector machine (SVM), it was found that SVM with an RBF kernel performed best with the AUC (area under the ROC curve) reaching 0.997, and the performance was better than the feature based on the full spectrum. This reveals that the peak area-based FTIR spectra combined with the SVM algorithm may be a promising tool in identifying the HCC foci and the paracancerous tissues.

Non-ischaemic cardiomyopathy associated with elevated serum cobalt and accelerated wear of a metal-on-metal hip resurfacing

A man in his late 30s developed non-ischaemic cardiomyopathy due to systemic cobalt toxicity associated with accelerated bearing surface wear from metal-on-metal hip resurfacing implanted in the previous 6 years. Following revision arthroplasty, the patient regained baseline cardiac function. Cobalt-induced cardiomyopathy is a grave condition that deserves early consideration due to potentially irreversible morbidity. We present this case to increase awareness, facilitate early detection and emphasise the need for research into the diagnosis and management of at-risk patients.

Biomolecular characterization of placental tissues in gestational diabetes mellitus using Fourier transform infrared microspectroscopy

Gestational diabetes mellitus (GDM) is a common complication during pregnancy. It could cause severe side-effect on the mother's and newborn's heath in the short- and long-term. Prevalence has been increasing over time, likely due to increases in mean maternal age and body weight. However, how GDM affects the placenta structure and function are still unclear. Fourier transform infrared microspectroscopy is well suited to study biological samples, such as tissues and cells. Biomolecules of human tissues have characteristic absorptions in mid-infrared range. In this study, Fourier transform infrared microspectroscopy was used to measure unfixed placental tissue sections from women with GDM and matched controls. The molecular composition of different type of placental tissue sections were further analyzed with principle component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The major spectral characteristic of biomolecules in GDM placental tissue and control group were compared. The conformational change of lipid chains and higher level of lipid oxidation were found for placental tissues from GDM pregnancies. The increase of proteins β-sheet structures relative to the α-helix structures in the GDM placental tissues were also found. The fingerprint region showed the variances of carbohydrates, nucleic acids and phospholipids between GDM and control group placental tissues. These findings are helpful for understanding how GDM affects placenta's biochemical composition and how GDM causes maternal and fetal metabolism changes. This study also provides a new approach to investigating biomolecular composition of samples from GDM pregnancy through spectroscopic method.

Silica-Carbonate of Ba(II) and Fe2+/Fe3+ Complex as Study Models to Understand Prebiotic Chemistry

The Precambrian era is called the first stage of the Earth history and is considered the longest stage in the geological time scale. Despite its duration, several of its environmental and chemical characteristics are still being studied. It is an era of special relevance not only for its duration but also because it is when a set of conditions gave rise to the first organism. This pioneer organism has been proposed to have been formed by a mineral and an organic part. A chemical element suggested to have been part of the structure of this cell is iron. However, what special characteristic does iron have with respect to other chemical elements to be proposed as part of this first cell? To answer this and other questions, it is indispensable to have a model that will allow extrapolating the first chemical structures of the pioneer organism formed in the Precambrian. In this context, for several decades, in vitro structures chemically formed by silica-carbonates have been synthetized, called biomorphs, because they could emulate living organisms and might resemble primitive organisms. It has been inferred that because biomorphs form structures with characteristic morphologies, they could resemble the microfossils found in the cherts of the Precambrian. Aiming at providing some insight on how iron contributed to the formation of the chemical structures of the primitive organism, we evaluated how iron contributes to the morphology and chemical-crystalline structure during the synthesis of these compounds under different conditions found in the primitive atmosphere. Experimentally, synthesis of biomorphs was performed at four different atmospheric conditions including UV light, nonionizing microwave radiation (NIR-mw), water steam (WS), and CO2 in the presence of Fe2+, Fe3+, and Fe2+/Fe3+, obtaining 48 different conditions. The produced biomorphs were observed under scanning electron microscopy (SEM). Afterward, their chemical composition and crystalline structure were analyzed through Raman and IR spectroscopy.

Assessment of the Antigenotoxic Effects of Alginate and ZnO/Alginate-Nanocomposites Extracted from Brown Alga Fucus vesiculosus in Mice

Mitomycin C (MMC) is an alkylating chemotherapy drug that could induce DNA damage and genetic alteration. It has been used as a model mutagen for in vivo and in vitro studies. The current study aimed to evaluate the protective role of Zinc oxide alginate–nanocomposites (ZnO-Alg/NCMs) against MMC–induced genotoxicity in mice. Animals were treated as follows: the control group, the groups treated with Algin (400 mg/kg b.w), the groups treated with ZnO-Alg/NCMs (400 mg/kg b.w), the group treated with MMC, and the groups treated with MMC plus Algin or ZnO-Alg/NCMs. Pre-treatment with Algin and ZnO-Alg/NCMs was repeated for one or seven days. Zinc oxide alginate-nanocomposites (ZnO-Alg/NCMs) were synthesized with the aim of incorporating the intrinsic properties of their constituents as an antigenotoxic substance. In this study, alginate was extracted from the brown marine alga Fucus vesiculosus, Zinc oxide nanoparticles were synthesized by using water extract of the same alga, and loaded in alginate to synthesize ZnO-Alg/NCMs. ZnO-NPs and ZnO-Alg/NCMs were characterized by TEM, SEM, EDX, and Zeta potential. The obtained results confirmed that by TEM and SEM, ZnO-NPs are rod shaped which modified, when loaded in alginate matrix, into spherical shape. The physical stability of ZnO-Alg/NCMs was reported to be higher than ZnO-NPs due to the presence of more negative charges on ZnO-Alg/NCMs. The EDX analysis indicated that the amount of zinc was higher in ZnO-NPs than ZnO-Alg/NCMs. The in vivo results showed that treatment with MMC induced genotoxic disturbances. The combined treatment with Algin and ZnO-Alg/NCMs succeeded in inducing significant protection against MMC. It could be concluded that ZnO-Algin/NCMs is a promising candidate to protect against MMC–induced genotoxicity.

Fourier-transform infrared microspectroscopy of pulmonary edema fluid for postmortem diagnosis of diabetic ketoacidosis

Determination of the cause of death for diabetic ketoacidosis (DKA), a common and fatal acute complication of diabetes mellitus, is a challenging forensic task owing to the lack of characteristic morphological findings at autopsy. In this study, Fourier-transform infrared (FTIR) microspectroscopy coupled with chemometrics was employed to characterize biochemical differences in pulmonary edema fluid from different causes of death to supplement conventional methods and provide an efficient postmortem diagnosis of DKA. With this aim, FTIR spectra in three different situations (DKA-caused death, other causes of death with diabetes history, and other causes of death without diabetes history) were measured. The results of principal component analysis indicated different spectral profiles between these three groups, which mainly exhibited variations in proteins. Subsequently, two binary classification models were established using an algorithm of partial least squares discriminant analysis (PLS-DA) to determine whether decedents had diabetes and whether the diabetic patients died from DKA. Satisfactory prediction results of PLS-DA models demonstrated good differentiation among these three groups. Therefore, it is feasible to make a postmortem diagnosis of DKA and detect diabetes history via FTIR microspectroscopic analysis of the pulmonary edema fluid.

Saliva based non invasive screening of Oral Submucous Fibrosis using ATR-FTIR spectroscopy

Oral Submucous Fibrosis (OSMF) is a type of precancerous condition of Oral cancer and considered to have the greatest malignant potential. Biopsy is an ultimate option for the conformation of the malignancy. But the invasiveness of the procedure makes it interdict. Therefore, there is an urgent need to identify effective screening and diagnostic methods which would be less invasive, rapid, more accurate and cost effective. Here, we used Attenuated Total Reflection- Fourier transform infrared spectroscopy (ATR-FTIR) with Chemometric analysis coupled with estimation of total salivary protein to discriminate OSMF and Healthy Control (HC). The present study showed the specific Infrared spectrum for OSMF patients, which was specifically differentiated from HC based on the spectral shift of proteins/amide II, carbohydrate and nucleic acid using Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) with small data sets. ATR-FTIR spectroscopy of saliva coupled with total protein estimation can be used to discriminate between OSMF and HC. However, large sample size should be needed to evaluate the ATR-FTIR for consideration as a screening tool for an early diagnosis OSMF.

ATR-IR and EPR spectroscopy for following the membrane restoration of isolated cortical synaptosomes in aluminium-induced Alzheimer's disease - Like rat model

Synaptosomal membrane peroxidation and alteration in its biophysical properties are associated with Aluminium (Al) toxicity that may lead to cognitive dysfunction and Alzheimer's disease (AD) like pathogenesis. Here we investigated the therapeutic potential of Lepedium sativum (LS) as a natural anti-inflammatory, antioxidant and as acetyl cholinesterase inhibitor in treating Al induced AD-like in rat model. We utilized ATR-IR spectroscopy to follow the restoration in the damaged membrane structure of isolated rat cortical synaptosomes and its biophysical properties, electron paramagnetic resonance (EPR) spin trapping to follow NADPH oxidase activity (NOX), and EPR spin labelling in response to LS treatment after Al intoxication. We measured the concentration of Ca²⁺ ions in rat cortical tissue by inductively coupled plasma (ICP), the brain atrophy/curing and hydrocephalus by magnetic resonance imaging (MRI) besides light microscope histopathology. Our results revealed significant increase in synaptosomal membrane rgidification, order, lipid packing, reactive oxygen species (ROS) production and Ca²⁺ ion concentration as a result of Al intoxication. The dramatic increase in Ca²⁺ ion concentration detected in AD group associated with the increase in synaptic membrane polarity and EPR-detected order S-parameter suggest that release of synaptic vesicles into synaptic cleft might be hindered. LS treatment reversed these changes in synaptic membranes, and rescued an observed deficit in the exploratory behaviour of AD group. Our results also strongly suggest that the synaptosomal membrane phospholipids that underwent free radical attacks mediated by AlCl3, due to greater NOX activity, was prevented in the LS group. The results of ATR-IR and EPR spectroscopic techniques recommend LS as a promising therapeutic agent against synaptic membrane alterations opening a new window for AD drug developers.

Plasma membrane proteins: A new probe for the characterization of breast cancer

This work aimed to characterize normal, benign and malignant excised breast tissues through the analysis of the FTIR spectra of their plasma membrane proteins. Tissue characterization parameters such as peak position, peak intensity, area under the peak, relative peak intensity and relative area under peak were evaluated mainly for protein spectral peaks; 1150 cm^-1, Amide I, Amide II, Amide III, and Amide A. The sensitivity, specificity and diagnostic accuracy for each parameter were obtained and Receiver Operating Characteristic (ROC) Curves were plotted. Results showed significant spectral differences between normal and benign tissues compared to malignant tissues at 1536 and 1645 cm^-1. The three tissues could be distinguished at 2900 cm^-1, where the malignant peak uniquely split into two separate peaks. ROC curves showed that the Amide A peak position yielded a higher accuracy compared to all other investigated characterization parameters. The deconvolution of Amide I revealed the conformational changes in plasma proteins characterizing the transformation to malignancy (a decrease in the percentage of alpha helix accompanied by an increase in the percentage of beta sheets). The use of the present structure-based analysis in conjunction with histopathological examination of excised breast tissues would offer an enhanced characterization that might reduce possible personal diagnostic mistakes.

Clinical biomarkers for cancer recognition and prevention: A novel approach with optical measurements

Cancer is the most important cause of death worldwide, and early cancer detection is the most fundamental factor for efficacy of treatment, prognosis, and increasing survival rate. Over the years great effort has been devoted to discovering and testing new biomarkers that can improve its diagnosis, especially at an early stage. Here we report the potential usefulness of new, easily applicable, non-invasive and relatively low-cost clinical biomarkers, based on abnormalities of oral mucosa spectral reflectance and fractal geometry of the vascular networks in several different tissues, for identification of hereditary non-polyposis colorectal cancer carriers as well for detection of other tumors, even at an early stage. In the near future the methodology/technology of these procedures should be improved, thus making possible their applicability worldwide as screening tools for early recognition and prevention of cancer.

Diagnosis of ovarian tumour tissues by SR-FTIR spectroscopy: A pilot study

Ovarian cancer is the seventh most common cancer among women across the world with very high mortality rates. Histology is considered the gold standard for tumour diagnosis. FTIR spectroscopy is relies on registering biochemical differences in the samples analysed, including biological specimens. Therefore, the Synchrotron radiation based-Fourier transform infrared spectroscopy (SR-FTIR) was used for the preliminary investigation of the molecular composition of the human, non-fixed ovarian neoplastic tissues with different type of biological potential. The study that was carried out on thin tissue sections, placed on barium fluoride infrared windows, was focused on investigating spatial distribution of the biochemical markers in various ovarian tumours. Since the structural constituents of tissues accumulate different molecules which may correspond to the specific type of ovarian tumours, the main goal of this study was to check if the mean intensities of the spectral lines of some bio-molecules can be treated as ovarian cancer bio-indicators. Moreover, an attempt to identify and understand the underlying biochemical changes associated with the disease was carried out. The major spectral differences in the frequency and intensities were identified as bonds of lipids, protein massif and nucleic acids. The results obtained suggest that Fourier transform infrared spectroscopy can be used as a supporting tool in the analysis of neoplastic ovarian tissue.

Serum-based diagnostic prediction of oral submucous fibrosis using FTIR spectrometry

Oral submucous fibrosis (OSF) is found to have the highest malignant potentiality among all other pre-cancerous lesions. However, its detection prior to tissue biopsy can be challenging in clinics. Moreover, biopsy examination is invasive and painful. Hence, there is an urgent need of new technology that facilitates accurate diagnostic prediction of OSF prior to biopsy. Here, we used FTIR spectroscopy coupled with chemometric techniques to distinguish the serum metabolic signatures of OSF patients (n=30) and healthy controls (n=30). Serum biochemical analyses have been performed to further support the FTIR findings. Absorbance intensities of 45 infrared wavenumbers differed significantly between OSF and normal serum FTIR spectra representing alterations in carbohydrates, proteins, lipids and nucleic acids. Nineteen prominent significant wavenumbers (P≤0.001) at 1020, 1025, 1035, 1039, 1045, 1078, 1055, 1100, 1117, 1122, 1151, 1169, 1243, 1313, 1398, 1453, 1544, 1650 and 1725cm^-1 provided excellent segregation of OSF spectra from normal using multivariate statistical techniques. These findings provided essential information on the metabolic features of blood serum of OSF patients and established that FTIR spectroscopy coupled with chemometric analysis can be potentially useful in the rapid and accurate preoperative screening/diagnosis of OSF.

Raman and infrared spectroscopy of carbohydrates: A review

Carbohydrates are widespread and naturally occurring compounds, and essential constituents for living organisms. They are quite often reported when biological systems are studied and their role is discussed. However surprisingly, up till now there is no database collecting vibrational spectra of carbohydrates and their assignment, as has been done already for other biomolecules. So, this paper serves as a comprehensive review, where for selected 14 carbohydrates in the solid state both FT-Raman and ATR FT-IR spectra were collected and assigned. Carbohydrates can be divided into four chemical groups and in the same way is organized this review. First, the smallest molecules are discussed, i.e. monosaccharides (d-(-)-ribose, 2-deoxy-d-ribose, l-(-)-arabinose, d-(+)-xylose, d-(+)-glucose, d-(+)-galactose and d-(-)-fructose) and disaccharides (d-(+)-sucrose, d-(+)-maltose and d-(+)-lactose), and then more complex ones, i.e. trisaccharides (d-(+)-raffinose) and polysaccharides (amylopectin, amylose, glycogen). Both Raman and IR spectra were collected in the whole spectral range and discussed looking at the specific regions, i.e. region V (3600-3050cm^-1), IV (3050-2800cm^-1) and II (1200-800cm^-1) assigned to the stretching vibrations of the OH, CH/CH₂ and C-O/C-C groups, respectively, and region III (1500-1200cm^-1) and I (800-100cm^-1) dominated by deformational modes of the CH/CH₂ and CCO groups, respectively. In spite of the fact that vibrational spectra of saccharides are significantly less specific than spectra of other biomolecules (e.g. lipids or proteins), marker bands of the studied molecules can be identified and correlated with their structure.

Honey Extracted Polyphenolics Reduce Experimental Hypoxia in Human Keratinocytes Culture

Hypoxic assault affects fundamental cellular processes and generates oxidative stress on healthy cells/molecules. Honey extracted polyphenolics (HEP) as a natural antioxidant reduced hypoxic cytotoxicity in this study. Different honey samples were physicochemically characterized to identify preferred (jamun) honey [pH 3.55 ± 0.04, conductivity (μs/cm) = 6.66 ± 0.14, water content % (w/w) = 14.70 ± 0.35, total solid content % (w/w) = 85.30 ± 0.35, phenol content (mg GAE/100 g) = 403.55 ± 0.35, flavonoid content (mg QE/100 g) = 276.76 ± 4.10, radical scavenging activity (% 500 μL) = 147.75 ± 3.13, catalase activity (absorbance at 620 nm) = 0.226 ± 0.01]. HEP was tested in different doses on hypoxic and normoxic cells (HaCaT) using viability and antioxidant assays. Cardinal molecular expressions such as cadherin-catenin-cytoskeleton complex (namely, E-cadherin, β-catenin, and F-actin), hypoxia marker (Hif 1 α), proliferation marker (Ki67), and epithelial master regulator (p63) were studied by immuno-cytochemisty (ICC) and qRT-PCR. The 0.063 mg/mL HEP demonstrated better vitality and functionality of HaCaT cells as per viability assay (*, P < 0.01) even under hypoxia. ICC and qRT-PCR observations indicated restoration of cellular survival and homeostasis under 0.063 mg/mL HEP after hypoxic assault. Furthermore, major spectral changes for nucleic acid and membrane phospholipid reorganizations by Fourier transform infrared spectroscopy illustrated a positive impact of 0.063 mg/mL HEP on hypoxic cells considering proliferation and cellular integrity. It was concluded that a specific dose of jamun HEP reduces hypoxic cytotoxicity.

Fourier transform infra-red spectroscopic signatures for lung cells' epithelial mesenchymal transition: A preliminary report

Infra red (IR) spectral characterization can provide label-free cellular metabolic signatures of normal and diseased circumstances in a rapid and non-invasive manner. Present study endeavoured to enlist Fourier transform infra red (FTIR) spectroscopic signatures for lung normal and cancer cells during chemically induced epithelial mesenchymal transition (EMT) for which global metabolic dimension is not well reported yet. Occurrence of EMT was validated with morphological and immunocytochemical confirmation. Pre-processed spectral data was analyzed using ANOVA and principal component analysis-linear discriminant analysis (PCA-LDA). Significant differences observed in peak area corresponding to biochemical fingerprint (900-1800cm^-1) and high wave-number (2800-3800cm^-1) regions contributed to adequate PCA-LDA segregation of cells undergoing EMT. The findings were validated by re-analysis of data using another in-house built binary classifier namely vector valued regularized kernel approximation (VVRKFA), in order to understand EMT progression. To improve the classification accuracy, forward feature selection (FFS) tool was employed in extracting potent spectral signatures by eliminating undesirable noise. Gradual increase in classification accuracy with EMT progression of both cell types indicated prominence of the biochemical alterations. Rapid changes in cellular metabolome noted in cancer cells within first 24h of EMT induction along with higher classification accuracy for cancer cell groups in comparison to normal cells might be attributed to inherent differences between them. Spectral features were suggestive of EMT triggered changes in nucleic acid, protein, lipid and bound water contents which can emerge as the useful markers to capture EMT related cellular characteristics.

Global spectral and local molecular connects for optical coherence tomography features to classify oral lesions towards unravelling quantitative imaging biomarkers

The biopsy based diagnosis of oral precancers like leukoplakia (OLK) and submucous fibrosis (OSF) as well as squamous cell carcinoma (OSCC) suffers from observer specific variability.

Effects of Very Low Dose Fast Neutrons on Cell Membrane And Secondary Protein Structure in Rat Erythrocytes

The effects of ionizing radiation on biological cells have been reported in several literatures. Most of them were mainly concerned with doses greater than 0.01 Gy and were also concerned with gamma rays. On the other hand, the studies on very low dose fast neutrons (VLDFN) are rare. In this study, we have investigated the effects of VLDFN on cell membrane and protein secondary structure of rat erythrocytes. Twelve female Wistar rats were irradiated with neutrons of total dose 0.009 Gy (²⁴¹Am-Be, 0.2 mGy/h) and twelve others were used as control. Blood samples were taken at the 0, 4th, 8th, and 12th days postirradiation. Fourier transform infrared (FTIR) spectra of rat erythrocytes were recorded. Second derivative and curve fitting were used to analysis FTIR spectra. Hierarchical cluster analysis (HCA) was used to classify group spectra. The second derivative and curve fitting of FTIR spectra revealed that the most significant alterations in the cell membrane and protein secondary structure upon neutron irradiation were detected after 4 days postirradiation. The increase in membrane polarity, phospholipids chain length, packing, and unsaturation were noticed from the corresponding measured FTIR area ratios. This may be due to the membrane lipid peroxidation. The observed band shift in the CH₂ stretching bands toward the lower frequencies may be associated with the decrease in membrane fluidity. The curve fitting of the amide I revealed an increase in the percentage area of α-helix opposing a decrease in the β-structure protein secondary structure, which may be attributed to protein denaturation. The results provide detailed insights into the VLDFN effects on erythrocytes. VLDFN can cause an oxidative stress to the irradiated erythrocytes, which appears clearly after 4 days postirradiation.

Diagnosis of colorectal cancer by near-infrared optical fiber spectroscopy and random forest

Near-infrared (NIR) spectroscopy has such advantages as being noninvasive, fast, relatively inexpensive, and no risk of ionizing radiation. Differences in the NIR signals can reflect many physiological changes, which are in turn associated with such factors as vascularization, cellularity, oxygen consumption, or remodeling. NIR spectral differences between colorectal cancer and healthy tissues were investigated. A Fourier transform NIR spectroscopy instrument equipped with a fiber-optic probe was used to mimic in situ clinical measurements. A total of 186 spectra were collected and then underwent the preprocessing of standard normalize variate (SNV) for removing unwanted background variances. All the specimen and spots used for spectral collection were confirmed staining and examination by an experienced pathologist so as to ensure the representative of the pathology. Principal component analysis (PCA) was used to uncover the possible clustering. Several methods including random forest (RF), partial least squares-discriminant analysis (PLSDA), K-nearest neighbor and classification and regression tree (CART) were used to extract spectral features and to construct the diagnostic models. By comparison, it reveals that, even if no obvious difference of misclassified ratio (MCR) was observed between these models, RF is preferable since it is quicker, more convenient and insensitive to over-fitting. The results indicate that NIR spectroscopy coupled with RF model can serve as a potential tool for discriminating the colorectal cancer tissues from normal ones.

The combination of artificial neural networks and synchrotron radiation-based infrared micro-spectroscopy for a study on the protein composition of human glial tumors

Protein-related changes associated with the development of human brain gliomas are of increasing interest in modern neuro-oncology.

Living matter observations with a novel hyperspectral supercontinuum confocal microscope for VIS to near-IR reflectance spectroscopy

A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.