Spectroscopy Biomarkers Research Articles

Raman Spectra of Blood Serum as Holistic Biomarker for Differential Auxiliary Diagnoses of Attention Deficit and Hyperactivity Disorder (ADHD) in Adults

Attention deficit and hyperactivity disorder (ADHD) is a prevalent neurodevelopmental condition, impacting approximately 10% of children globally. A significant proportion, around 30–50%, of those diagnosed during childhood continue to manifest ADHD symptoms into adulthood, with 2–5% of adults experiencing the condition. The existing diagnostic framework for ADHD relies on clinical assessments and interviews conducted by healthcare professionals. This diagnostic process is complicated by the disorder’s overlap in symptoms and frequent comorbidities with other neurodevelopmental conditions, particularly bipolar disorder during its manic phase, adding complexity to achieving accurate and timely diagnoses. Despite extensive efforts to identify reliable biomarkers that could enhance the clinical diagnosis, this objective remains elusive. In this study, Raman spectroscopy, combined with multivariate statistical methods, was employed to construct a model based on the analysis of blood serum samples. The developed partial least-squares discriminant analysis (PLS-DA) model demonstrated an ability to differentiate between individuals with ADHD, healthy individuals, and those diagnosed with bipolar disorder in the manic phase, with a total accuracy of 97.4%. The innovative approach in this model involves utilizing the entire Raman spectrum, within the 450–1720 cm−1 range, as a comprehensive representation of the biochemical blood serum setting, thus serving as a holistic spectroscopic biomarker. This method circumvents the necessity to pinpoint specific chemical substances associated with the disorders, eliminating the reliance on specific molecular biomarkers. Moreover, the developed model relies on a sensitive and reliable technique that is cost-effective and rapid, presenting itself as a promising complementary diagnostic tool for clinical settings. The potential for Raman spectroscopy to contribute to the diagnostic process suggests a step forward in addressing the challenges associated with accurately identifying and distinguishing ADHD from other related conditions.

Aerobic Anoxygenic Phototrophic Bacteria in the Marine Environments Revealed by Raman/Fluorescence-Guided Single-Cell Sorting and Targeted Metagenomics.

Aerobic anoxygenic phototrophic bacteria (AAPB) contribute profoundly to the global carbon cycle. However, most AAPB in marine environments are uncultured and at low abundance, hampering the recognition of their functions and molecular mechanisms. In this study, we developed a new culture-independent method to identify and sort AAPB using single-cell Raman/fluorescence spectroscopy. Characteristic Raman and fluorescent bands specific to bacteriochlorophyll a (Bchl a) in AAPB were determined by comparing multiple known AAPB with non-AAPB isolates. Using these spectroscopic biomarkers, AAPB in coastal seawater, pelagic seawater, and hydrothermal sediment samples were screened, sorted, and sequenced. 16S rRNA gene analysis and functional gene annotations of sorted cells revealed novel AAPB members and functional genes, including one species belonging to the genus Sphingomonas, two genera affiliated to classes Betaproteobacteria and Gammaproteobacteria, and function genes bchCDIX, pucC2, and pufL related to Bchl a biosynthesis and photosynthetic reaction center assembly. Metagenome-assembled genomes (MAGs) of sorted cells from pelagic seawater and deep-sea hydrothermal sediment belonged to Erythrobacter sanguineus that was considered as an AAPB and genus Sphingomonas, respectively. Moreover, multiple photosynthesis-related genes were annotated in both MAGs, and comparative genomic analysis revealed several exclusive genes involved in amino acid and inorganic ion metabolism and transport. This study employed a new single-cell spectroscopy method to detect AAPB, not only broadening the taxonomic and genetic contents of AAPB in marine environments but also revealing their genetic mechanisms at the single-genomic level.

Steps on the Path to Clinical Translation: A workshop by the British and Irish Chapter of the ISMRM.

The British and Irish Chapter of the International Society for Magnetic Resonance in Medicine (BIC-ISMRM) held a workshop entitled "Steps on the path to clinical translation" in Cardiff, UK, on 7th September 2022. The aim of the workshop was to promote discussion within the MR community about the problems and potential solutions for translating quantitative MR (qMR) imaging and spectroscopic biomarkers into clinical application and drug studies. Invited speakers presented the perspectives of radiologists, radiographers, clinical physicists, vendors, imaging Contract/Clinical Research Organizations (CROs), open science networks, metrologists, imaging networks, and those developing consensus methods. A round-table discussion was held in which workshop participants discussed a range of questions pertinent to clinical translation of qMR imaging and spectroscopic biomarkers. Each group summarized their findings via three main conclusions and three further questions. These questions were used as the basis of an online survey of the broader UK MR community.

Raman microspectroscopy identifies fibrotic tissues in collagen-related disorders via deconvoluted collagen type I spectra.

Fibrosis is a consequence of the pathological remodeling of extracellular matrix (ECM) structures in the connective tissue of an organ. It is often caused by chronic inflammation, which over time, progressively leads to an excess deposition of collagen type I (COL I) that replaces healthy tissue structures, in many cases leaving a stiff scar. Increasing fibrosis can lead to organ failure and death; therefore, developing methods that potentially allow real-time monitoring of early onset or progression of fibrosis are highly valuable. In this study, the ECM structures of diseased and healthy human tissue from multiple organs were investigated for the presence of fibrosis using routine histology and marker-independent Raman microspectroscopy and Raman imaging. Spectral deconvolution of COL I Raman spectra allowed the discrimination of fibrotic and non-fibrotic COL I fibers. Statistically significant differences were identified in the amide I region of the spectral subpeak at 1608cm-1, which was deemed to be representative for structural changes in COL I fibers in all examined fibrotic tissues. Raman spectroscopy-based methods in combination with this newly discovered spectroscopic biomarker potentially offer a diagnostic approach to non-invasively track and monitor the progression of fibrosis. STATEMENT OF SIGNIFICANCE: Current diagnosis of fibrosis still relies on histopathological examination with invasive biopsy procedures. Although, several non-invasive imaging techniques such as positron emission tomography, single-photon emission computed tomography and second harmonic generation are gradually employed in preclinical or clinical studies, these techniques are limited in spatial resolution and the morphological interpretation highly relies on individual experience and knowledge. In this study, we propose a non-destructive technique, Raman microspectroscopy, to discriminate fibrotic changes of collagen type I based on a molecular biomarker. The changes of the secondary structure of collagen type I can be identified by spectral deconvolution, which potentially can provide an automatic diagnosis for fibrotic tissues in the clinical applicaion.

Synchrotron Fourier Transform Infrared Microscopy Spectra in Cellular Effects of Janus Kinase Inhibitors on Myelofibrosis Cancer Cells

Janus kinase (JAK) deregulation of the JAK/signal transducers and activators of transcription pathway leads to myelofibrosis that can be treated by JAK inhibitors including Ruxolitinib and Tofacitinib. Even though both inhibitors are effective against myelofibrosis, each of them has a different mode of action in the cells. Ruxolitinib is an inhibitor for selective JAK1/2, and Tofacitinib is an inhibitor for JAK3. This study evaluated the chemical fingerprints of TF-1 cells after JAK inhibitor treatments by the synchrotron Fourier transform infrared microspectroscopy (S-FTIR) spectrum. Tofacitinib and Ruxolitinib treatments in TF-1 cells were applied with a chemical fingerprint approach in S-FTIR spectroscopy and in vitro cytotoxicity in a cell-based assay. Principal component analysis or PCA was utilized to classify three cell treatments with three biochemical alteration absorbances of lipid vibration by the C–H stretching, protein amide I that appeared from the C=O stretching, and a P=O phosphodiester bond from nucleic acids. The results showed that the inhibition effect of Ruxolitinib on the TF-1 cell lines was two-fold higher than Tofacitinib. PCA distinguishes untreated and drug-treated cells by detecting cellular biochemical alteration. The loading plots identify that proteins and nucleic acids were the different main components in disparate cell treatments. Tofacitinib was distinct from the others in lipid and nucleic acid. The second derivative spectra of the three molecular components had decreased lipid production and accumulation, changes in secondary structures in proteins, and a high level of RNA overexpression in cell treatment. The JAK inhibitors caused different spectroscopic biomarkers of the modifications of secondary protein conformation, stimulated cell lipid accumulation, and phosphorylation from untreated cells. The alteration of cellular biochemical components suggests that FTIR is a potential tool to analyze specific patterns of drug cellular responses at the molecular level.

The impact of moderate heating on human bones: an infrared and neutron spectroscopy study.

This study aims to analyse human bones exposed to low/medium temperatures (200–650°C) under experimentally controlled conditions, both oxidizing and reducing, using complementary optical and neutron vibrational spectroscopy techniques. Clear differences were observed between the aerobically and anaerobically heated bones. The organic constituents disappeared at lower temperatures for the former (ca 300°C), while they lingered for higher temperatures in anaerobic environments (ca 450–550°C). Unsaturated non-graphitizing carbon species (chars) were detected mainly for anaerobically heated samples, and cyanamide formation occurred only at 650°C in reducing settings. Overall, the main changes were observed from 300 to 400°C in anaerobic conditions and from 450 to 500°C in aerobic environments. The present results enabled the identification of specific spectroscopic biomarkers of the effect of moderate temperatures (less than or equal to 650°C) on human bone, thus contributing to a better characterization of forensic and archaeological skeletal remains subject to heating under distinct environmental settings. In particular, these data may provide information regarding cannibalism or ancient bone boiling and defleshing rituals.

PLS-DA Model for the Evaluation of Attention Deficit and Hyperactivity Disorder in Children and Adolescents through Blood Serum FTIR Spectra.

Attention deficit and hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood. It affects ~10% of the world’s population of children, and about 30–50% of those diagnosed in childhood continue to show ADHD symptoms later, with 2–5% of adults having the condition. Current diagnosis of ADHD is based on the clinical evaluation of the patient, and on interviews performed by clinicians with parents and teachers of the children, which, together with the fact that it shares common symptoms and frequent comorbidities with other neurodevelopmental disorders, makes the accurate and timely diagnosis of the disorder a difficult task. Despite the large effort to identify reliable biomarkers that can be used in a clinical environment to support clinical diagnosis, this goal has never been achieved hitherto. In the present study, infrared spectroscopy was used together with multivariate statistical methods (hierarchical clustering and partial least-squares discriminant analysis) to develop a model based on the spectra of blood serum samples that is able to distinguish ADHD patients from healthy individuals. The developed model used an approach where the whole infrared spectrum (in the 3700–900 cm−1 range) was taken as a holistic imprint of the biochemical blood serum environment (spectroscopic biomarker), overcoming the need for the search of any particular chemical substance associated with the disorder (molecular biomarker). The developed model is based on a sensitive and reliable technique, which is cheap and fast, thus appearing promising to use as a complementary diagnostic tool in the clinical environment.

Multimodal, label-free fluorescence and Raman imaging of amyloid deposits in snap-frozen Alzheimer\u2019s disease human brain tissue

Alzheimer’s disease (AD) neuropathology is characterized by hyperphosphorylated tau containing neurofibrillary tangles and amyloid-beta (Aβ) plaques. Normally these hallmarks are studied by (immuno-) histological techniques requiring chemical pretreatment and indirect labelling. Label-free imaging enables one to visualize normal tissue and pathology in its native form. Therefore, these techniques could contribute to a better understanding of the disease. Here, we present a comprehensive study of high-resolution fluorescence imaging (before and after staining) and spectroscopic modalities (Raman mapping under pre-resonance conditions and stimulated Raman scattering (SRS)) of amyloid deposits in snap-frozen AD human brain tissue. We performed fluorescence and spectroscopic imaging and subsequent thioflavin-S staining of the same tissue slices to provide direct confirmation of plaque location and correlation of spectroscopic biomarkers with plaque morphology; differences were observed between cored and fibrillar plaques. The SRS results showed a protein peak shift towards the β-sheet structure in cored amyloid deposits. In the Raman maps recorded with 532 nm excitation we identified the presence of carotenoids as a unique marker to differentiate between a cored amyloid plaque area versus a non-plaque area without prior knowledge of their location. The observed presence of carotenoids suggests a distinct neuroinflammatory response to misfolded protein accumulations.

The anti-neuroinflammatory effects of Clinacanthus nutans leaf extract on metabolism elucidated through 1H NMR in correlation with cytokines microarray.

Clinacanthus nutans (CN) (Acanthaceae) is well-known for its anti-inflammatory properties among Asian communities; however, there are currently no data specifically focused on the anti-inflammatory effects of CN on the brain tissue. Neuroinflammation is a common consequence of toxin intrusion to any part of the central nervous system (CNS). As an innate immune response, the CNS may react through both protective and/or toxic actions due to the activation of neuron cells producing pro- and/or anti-inflammatory cytokines in the brain. The unresolved activation of the inflammatory cytokines’ response is associated with the pathogenesis of neurological disorders. The present study aimed to decipher the metabolic mechanism on the effects of 14 days oral treatment with CN aqueous extract in induced-lipopolysaccharides (LPS) rats through 1H NMR spectroscopic biomarker profiling of the brain tissue and the related cytokines. Based on the principal component analysis (PCA) of the nuclear magnetic resonance (NMR) spectral data, twenty-one metabolites in the brain tissue were profiled as biomarkers for the LPS (10 μL)-induced neuroinflammation following intracerebroventricular injection. Among the twenty-one biomarkers in the neuroinflammed rats, CN treatment of 1000 and 500 mg/kg BW successfully altered lactate, pyruvate, phosphorylcholine, glutamine, and α-ketoglutarate when compared to the negative control. Likewise, statistical isolinear multiple component analysis (SIMCA) showed that treatments by CN and the positive control drug, dextromethorphan (DXM, 5 mg/kg BW), have anti-neuroinflammatory potential. A moderate correlation, in the orthogonal partial least squares (OPLS) regression model, was found between the spectral metabolite profile and the cytokine levels. The current study revealed the existence of high levels of pro-inflammatory cytokines, namely IL-1α, IL-1β, and TNF-α in LPS-induced rats. Both CN dose treatments lowered IL-1β significantly better than DXM Interestingly, DXM and CN treatments both exhibited the upregulation of the anti-inflammatory cytokines IL-2 and 4. However, DXM has an advantage over CN in that the former also increased the expression of IL-10 of anti-inflammatory cytokines. In this study, a metabolomics approach was successfully applied to discover the mechanistic role of CN in controlling the neuroinflammatory conditions through the modulation of complex metabolite interactions in the rat brain.

Novel spectroscopic biomarkers are applicable in non-invasive early detection and staging classification of colorectal cancer.

Colorectal cancer (CRC) remains a significant threat to human health because of the lack of awareness of physical examination or the limitations of an early diagnostic level. Despite the improving standard of modern medicine, mortality from CRC is still remarkably high and the prognosis remains poor in many cases because of disease detection at advanced clinical stages. Raman spectroscopy yields precise information, not only regarding the secondary structure of proteins but also regarding the discrimination between normal and malignant tissues. We investigated whether this method can be used for the diagnosis of CRC including initial stages. To acquire more detailed structural information, we tested a novel diagnostic approach based on a suitable combination of conventional methods of molecular spectroscopy (Raman and Fourier transform infrared) with advanced, highly structure-sensitive chiroptical techniques as electronic circular dichroism (ECD) and Raman optical activity (ROA) to monitor the CRC pathogenesis relating compositional, structural and conformational changes in blood biomolecules, some of which may be caused by pathological processes occurring during cancer growth, also at the beginning of the disease. Sixty-three blood plasma samples were analyzed using the combination of ECD and ROA supplemented by Raman and Fourier transform infrared (FT-IR) spectroscopies. The obtained spectra were evaluated together by linear discriminant analysis. The accuracy of sample discrimination reached 100% and the subsequent leave-one-out cross-validation resulted in 90% sensitivity and 75% specificity. There were also found the differences between the patients according to the clinical stage. The achieved results suggest a panel of promising biomarkers and indicate that chiroptical methods combined with conventional spectroscopies might be a new minimally invasive powerful tool for producing high-quality data, obtaining an accurate diagnosis of colorectal cancer through a peripheral blood sample, which is also able to determine the extent of this pathology. Further work needs to be carried out for these techniques to be implemented in the clinical setting.

Saliva as a first-line diagnostic tool: A spectral challenge for identification of cancer biomarkers

Abstract The paper concentrates on the role of saliva in the early diagnosis of salivary gland tumor. Due to the still not fully understood etiology of head and neck cancer, the fundamental objective of this study is to find tumor markers of salivary gland tumor progression. This work demonstrates the feasibility of Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR) to track spectral variations between saliva samples derived from healthy volunteers and from salivary gland tumor (tumor mixus, TM) patients. Furthermore, a Real-Time Polymerase Chain Reaction (RT-PCR) has been used to detect a selected genes expression associated with neoplasm changes. The obtained results imply that spectral signals attributed to the amide I/II (secondary structure of protein), carbohydrates and inorganic phosphates oscillations are the most sensitive to alterations associated with the salivary gland cancer progression. Several spectroscopic biomarkers have been indicated as potential predictors of salivary gland tumor development. Additionally, the RT-PCR results reveal the increased level of Bcl-2 factor in salivary gland tumor patients' samples which may be related to inhibition of apoptosis process and increasing uncontrolled cell proliferation. Such combination of physico-chemical methods is a unique approach towards better understanding the tumor's etiology and early diagnosis problem. Based on the promising findings presented in this article, it could be concluded that saliva fluid has a great potential to be used as a first-line diagnostic tool in patients with suspicion of salivary gland tumor.

Infrared biomarkers of impaired cystic fibrosis transmembrane regulator protein biogenesis.

The mid-infrared (IR) spectra of human cystic fibrosis (CF) cells acquired by Fourier transform infrared microspectroscopy were compared with those of non-CF cells. Within the 1700 to 1480 cm-1 spectral domain of amides, unsupervised explorative principal component analysis identified a few variables reflecting quantitative and qualitative vibrations arising from protein secondary structures and amino acid side chains. Their pattern reflected α-helix to β-sheet transitions in bronchial epithelial cells and in immortalized peripheral blood mononuclear cells from patients with R1162X missense or in-frame F508del mutations in the cystic fibrosis transmembrane regulator gene (Cftr). Similar transitions have been described in IR spectra of cells, tissues and body fluids of patients affected with some neurodegenerative diseases characterized by the accumulation of misfolded protein aggregates. The variables pattern was able to distinguish CF cells from non-CF cells and was modified by molecular compounds used to rescue the unbalanced folding process of mutated cystic fibrosis transmembrane regulator (CFTR) anion channel. To our knowledge, this is the first experimental evidence of spectroscopic biomarkers of the impaired biogenesis of CFTR by IR microanalysis in the spectra of human CF bronchial epithelial and lymphoblastoid cells.

FT Raman spectroscopy in the evaluation of biomarkers of normal and pathological placenta tissue

The basic precondition of proper intrauterine growth is appropriate supply of nutrients transported through placenta. Placenta capacity in the scope of transportation is dependent on transport systems and the structure of the basement membrane and syncytiotrophoblast microvillous membrane. The present pilot study demonstrates preliminary results of the analysis of placenta structure in the course of selected pathologies by FT Raman spectroscopy analysis. The observed changes of the molecular structure in the so-called average spectra, independent of methodical processing, may be an indicator of the efficiency of transportation controlled by syncytiotrophoblast. In particular, an increase in the intensity of dispersion and transfer within the frequency of 3425–3300 cm−1 demonstrate the dynamics of the interaction in the scope of hydrogen bonds in healthy tissues. Changes in the molecular structure within the frequency of 950–750 cm−1 and conformational changes within disulphide bonds differentiate the healthy tissue from the pathological one. Changes in the molecular structure observed in the FTR spectra are a spectroscopic image of placenta functions in the course of various pathologies. They also document a complex goal of our research that is finding spectroscopic biomarkers of regular and pathological placental tissue.

Current and Novel Methods in Clinical Microbiology: Advantages and Pitfalls when Facing the Menace of Antimicrobial Resistance

Microbiological clinical methods were the object of this review. According to WHO antimicrobial resistance is a real and global threat. Researchers aim to develop rapid methods for identification and antimicrobial susceptibility (AST). Actually, most automated solutions available in clinical laboratories are based upon the study of the microbial ability to grow so, take a long time to give results despite its advantages. Molecular tests only detect target genes but are especially useful regarding identification of difficult or slow growing microorganisms. MALDI-TOF started a real revolution in microbial identification since it is growth independent and highly sensitive and specific. Regarding susceptibility evaluation, due to its inherent complexity, molecular or proteomic tests provides answers to known and molecular characterized mechanisms, requiring its prior knowledge. Flow cytometry is an excellent tool that, coupled with specific fluorescent antibodies can be used to identify microorganisms. Moreover, it can help to unveil susceptibility profile. AST phenotype is provided following incubation of the cells for short period (60 minutes) with antimicrobial drugs and fluorescent probes, with excellent correlation with classic AST methods. Furthermore, it can elucidate about the most relevant mechanism of resistance in a functional assay. Novel methods are under study namely sophisticated methods for growth detection like, weighing bacteria by vibrating cantilevers, isothermal microcalorimetry method, simple spectroscopic biomarkers and plasmonic imaging and tracking are discussed. We are close to a change of the paradigm in the clinical laboratory work flow microbiology considering especially MALDI-TOF for identification and flow cytometry for AST/assessment of mechanisms of resistance.

FT-IR- and Raman-based biochemical profiling of the early stage of pulmonary metastasis of breast cancer in mice.

The combination of FT-IR and Raman spectroscopies allowed the biochemical profiling of lungs in the early stage of pulmonary metastasis in the murine model of breast cancer. Histological staining was used as a reference. Raman spectroscopy was especially useful in the detection and semi-quantitative analysis of the vitamin A content in lung lipofibroblasts, whereas the IR technique provided semi-quantitative information on the contents of nucleic acids, carbohydrates including glycogen, and lipids as well as changes in the secondary structures of tissue proteins. Our spectroscopic results suggest that the early phase of metastasis in the lung is characterized by a decrease in the endogenous retinoid content in combination with a decrease in the content of glycogen and lipids.

Changes in spectroscopic biomarkers after transcranial direct current stimulation in children with perinatal stroke

BackgroundPerinatal stroke causes lifelong motor disability, affecting independence and quality of life. Non-invasive neuromodulation interventions such as transcranial direct current stimulation (tDCS) combined with intensive therapy may improve motor function in adult stroke hemiparesis but is under-explored in children. Measuring cortical metabolites with proton magnetic resonance spectroscopy (MRS) can inform cortical neurobiology in perinatal stroke but how these change with neuromodulation is yet to be explored. MethodsA double-blind, sham-controlled, randomized clinical trial tested whether tDCS could enhance intensive motor learning therapy in hemiparetic children. Ten days of customized, goal-directed therapy was paired with cathodal tDCS over contralesional primary motor cortex (M1, 20 min, 1.0 mA, 0.04 mA/cm2) or sham. Motor outcomes were assessed using validated measures. Neuronal metabolites in both M1s were measured before and after intervention using fMRI-guided short-echo 3T MRS. ResultsFifteen children [age(range) = 12.1(6.6–18.3) years] were studied. Motor performance improved in both groups and tDCS was associated with greater goal achievement. After cathodal tDCS, the non-lesioned M1 showed decreases in glutamate/glutamine and creatine while no metabolite changes occurred with sham tDCS. Lesioned M1 metabolite concentrations did not change post-intervention. Baseline function was highly correlated with lesioned M1 metabolite concentrations (N-acetyl-aspartate, choline, creatine, glutamate/glutamine). These correlations consistently increased in strength following intervention. Metabolite changes were not correlated with motor function change. Baseline lesioned M1 creatine and choline levels were associated with clinical response. ConclusionsMRS metabolite levels and changes may reflect mechanisms of tDCS-related M1 plasticity and response biomarkers in hemiparetic children with perinatal stroke undergoing intensive neurorehabilitation.

Raman spectral markers of collagen denaturation and hydration in human cortical bone tissue are affected by radiation sterilization and high cycle fatigue damage.

Thermal denaturation and monotonic mechanical damage alter the organic and water-related compartments of cortical bone. These changes can be detected using Raman spectroscopy. However, less is known regarding Raman sensitivity to detect the effects of cyclic fatigue damage and allograft sterilization doses of gamma radiation. To determine if Raman spectroscopic biomarkers of collagen denaturation and hydration are sensitive to the effects of (a) high cycle fatigue damage and (b) 25kGy irradiation. Unirradiated and gamma-radiation sterilized human cortical bone specimens previously tested in vitro under high-cycle (> 100,000 cycles) fatigue conditions at 15MPa, 25MPa, 35MPa, 45MPa, and 55MPa cyclic stress levels were studied. Cortical bone Raman spectral profiles from wavenumber ranges of 800-1750cm-1 and 2700-3800cm-1 were obtained and compared from: a) non-fatigue vs fatigue fracture sites and b) radiated vs. unirradiated states. Raman biomarker ratios 1670/1640 and 3220/2949, which reflect collagen denaturation and organic matrix (mainly collagen)-bound water, respectively, were assessed. One- and two-way ANOVA analyses were utilized to identify differences between groups along with interaction effects between cyclic fatigue and radiation-induced damage. Cyclic fatigue damage resulted in increases in collagen denaturation (1670/1640: 1.517 ± 0.043 vs 1.579 ± 0.021, p < 0.001) and organic matrix-bound water (3220/2949: 0.109 ± 0.012 vs 0.131 ± 0.008, p < 0.001). Organic matrix-bound water increased secondary to 25kGy irradiation (3220/2949: 0.105 ± 0.010 vs 0.1161 ± 0.009, p = 0.003). Organic matrix-bound water was correlated positively with collagen denaturation (r = 0.514, p < 0.001). Raman spectroscopy can detect the effects of cyclic fatigue damage and 25kGy irradiation via increases in organic matrix (mainly collagen)-bound water. A Raman measure of collagen denaturation was sensitive to cyclic fatigue damage but not 25kGy irradiation. Collagen denaturation was correlated with organic matrix-bound water, suggesting that denaturation of collagen to gelatinous form may expose more binding sites to water by unwinding the triple alpha chains. This research may eventually be useful to help identify allograft quality and more appropriately match donors to recipients.

Spectroscopic biomarkers of motor cortex developmental plasticity in hemiparetic children after perinatal stroke.

Perinatal stroke causes hemiparetic cerebral palsy and lifelong motor disability. Bilateral motor cortices are key hubs within the motor network and their neurophysiology determines clinical function. Establishing biomarkers of motor cortex function is imperative for developing and evaluating restorative interventional strategies. Proton magnetic resonance spectroscopy (MRS) quantifies metabolite concentrations indicative of underlying neuronal health and metabolism in vivo. We used functional magnetic resonance imaging (MRI)-guided MRS to investigate motor cortex metabolism in children with perinatal stroke. Children aged 6-18 years with MRI-confirmed perinatal stroke and hemiparetic cerebral palsy were recruited from a population-based cohort. Metabolite concentrations were assessed using a PRESS sequence (3T, TE = 30 ms, voxel = 4 cc). Voxel location was guided by functional MRI activations during finger tapping tasks. Spectra were analysed using LCModel. Metabolites were quantified, cerebral spinal fluid corrected and compared between groups (ANCOVA) controlling for age. Associations with clinical motor performance (Assisting Hand, Melbourne, Box-and-Blocks) were assessed. Fifty-two participants were studied (19 arterial, 14 venous, 19 control). Stroke participants demonstrated differences between lesioned and nonlesioned motor cortex N-acetyl-aspartate [NAA mean concentration = 10.8 ± 1.9 vs. 12.0 ± 1.2, P < 0.01], creatine [Cre 8.0 ± 0.9 vs. 7.4 ± 0.9, P < 0.05] and myo-Inositol [Ins 6.5 ± 0.84 vs. 5.8 ± 1.1, P < 0.01]. Lesioned motor cortex NAA and creatine were strongly correlated with motor performance in children with arterial but not venous strokes. Interrogation of motor cortex by fMRI-guided MRS is feasible in children with perinatal stroke. Metabolite differences between hemispheres, stroke types and correlations with motor performance support functional relevance. MRS may be valuable in understanding the neurophysiology of developmental neuroplasticity in cerebral palsy. Hum Brain Mapp 38:1574-1587, 2017. © 2016 Wiley Periodicals, Inc.

Multimodal magnetic resonance imaging and spectroscopy for prostate cancer screening and staging

Introduction Multi-modal magnetic resonance imaging (MRI) combining T2-weighted imaging with advanced techniques such as diffusion-weighted imaging (DWI), dynamic contrast and proton spectroscopy is a promising tool for prostate cancer screening, staging and treatment planning. Purpose Evaluation and optimization of multi-modal MRI techniques for prostate cancer screening, staging and treatment planning. Materials and methods Participants at high risk of prostate cancer underwent MRI scans including T2-weighted imaging, DWI using echo planar readout, 3D chemical shift imaging (CSI) and dynamic contrast enhanced imaging on a 3T Siemens scanner with data acquisition using spine and surface coils only. The results were analyzed using vendor-supplied and in-house software and scored according to the “Prostate imaging reporting and data system (PI-RADS)” scoring system. Results Despite the promise of spectroscopic biomarkers as a diagnostic tool, the CSI spectra acquired using standard sequences proved generally of insufficient quality for reliable biomarker estimation. Scanner produced metabolite maps proved highly variable and prone to misidentification of metabolites due to poorly resolved peaks. Apparent diffusion coefficient (ADC) maps appeared diagnostically more useful although low signal and noise floor issues at higher b-values also affected the estimation of ADCs and apparent kurtosis observed at low b-values, casting some doubt on the reliability of high kurtosis values reported in the literature for prostate diffusion kurtosis imaging (DKI). Conclusion Reliable quantification of spectroscopic biomarkers for prostate cancer requires improved protocols for CSI and spectroscopy. Apparent kurtosis observed for diffusion weighted images acquired at low maximum b-values are require further validation.

Rapid bacterial antibiotic susceptibility test based on simple surface-enhanced Raman spectroscopic biomarkers.

Rapid bacterial antibiotic susceptibility test (AST) and minimum inhibitory concentration (MIC) measurement are important to help reduce the widespread misuse of antibiotics and alleviate the growing drug-resistance problem. We discovered that, when a susceptible strain of Staphylococcus aureus or Escherichia coli is exposed to an antibiotic, the intensity of specific biomarkers in its surface-enhanced Raman scattering (SERS) spectra drops evidently in two hours. The discovery has been exploited for rapid AST and MIC determination of methicillin-susceptible S. aureus and wild-type E. coli as well as clinical isolates. The results obtained by this SERS-AST method were consistent with that by the standard incubation-based method, indicating its high potential to supplement or replace existing time-consuming methods and help mitigate the challenge of drug resistance in clinical microbiology.