RESUMO
BACKGROUND: One-dimensional proton nuclear magnetic resonance (1D 1H NMR) spectroscopy is a non-destructive, non-targeted analytical technique providing both qualitative and quantitative insights, particularly beneficial for mixture analysis. However, the qualitative analysis of 1D 1H NMR spectra for mixture samples is laborious and time-consuming, involving extensive database searches and verification experiments like spiking. This process heavily relies on the analyst's expertise, leading to efficiency discrepancies. There is a pressing need for a reliable method to streamline operations and enhance the efficiency of qualitative analysis in complex mixtures. RESULTS: We introduce a library-aided method for spectral profiling, named LAMAIS. This method achieves compound identification through similarity assessment between samples and template data, allowing rapid, automatic compound identification and full-spectrum peak assignment without the need for fitting. LAMAIS correctly identifies over 90 % of components in synthetic mixtures and more than 75 % in experimental mixtures, surpassing other representative methods with a higher F2 score. Our reference library, which currently includes 71 compounds, is tailored to capture the commonality of primary metabolites across diverse plant species. The analysis of real-world samples yielded encouraging results, underscoring LAMAIS's versatility as an auxiliary tool suitable for a variety of botanical sources. For analyst convenience, interactive graphics are utilized as the output format. SIGNIFICANCE: LAMAIS excels, demonstrating competitiveness and reliability. The approach minimizes repetitive tasks and sample wastage, improving the efficiency of 1D 1H NMR qualitative analysis. Constructing a reference library effectively preserves knowledge, mitigates reliance on human experience, and addresses gaps in the analysis of plant source samples.
Assuntos
Metabolômica , Plantas , Espectroscopia de Prótons por Ressonância Magnética , Metabolômica/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Plantas/química , Plantas/metabolismoRESUMO
AIMS: The study aimed to assess brain metabolite differences in the medial prefrontal cortex (mPFC) between acute and euthymic episodes of bipolar disorder (BD) with both mania and depression over a 6-month medication treatment period. METHODS: We utilized 1H-MRS technology to assess the metabolite levels in 53 individuals with BD (32 in depressive phase, 21 in manic phase) and 34 healthy controls (HCs) at baseline. After 6 months of medication treatment, 40 subjects underwent a follow-up scan in euthymic state. Metabolite levels, including N-acetyl aspartate (NAA), glutamate (Glu), and Glutamine (Gln), were measured in the mPFC. RESULTS: Patients experiencing depressive and manic episodes exhibited a notable reduction in NAA/Cr + PCr ratios at baseline compared to healthy controls (p = 0.004; p = 0.006) in baseline, compared with HCs. Over the 6-month follow-up period, the manic group displayed a significant decrease in Gln/Cr + PCr compared to the initial acute phase (p = 0.03). No significant alterations were found in depressed group between baseline and follow-up. CONCLUSION: This study suggests that NAA/Cr + PCr ratios and Gln/Cr + PCr ratios in the mPFC may be associated with manic and depressive episodes, implicating that Gln and NAA might be useful biomarkers for distinguishing mood phases in BD and elucidating its mechanisms.
Assuntos
Ácido Aspártico , Transtorno Bipolar , Ácido Glutâmico , Glutamina , Córtex Pré-Frontal , Espectroscopia de Prótons por Ressonância Magnética , Humanos , Transtorno Bipolar/tratamento farmacológico , Transtorno Bipolar/metabolismo , Transtorno Bipolar/diagnóstico por imagem , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/diagnóstico por imagem , Masculino , Feminino , Adulto , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Glutamina/metabolismo , Ácido Glutâmico/metabolismo , Pessoa de Meia-Idade , Seguimentos , Creatina/metabolismo , Adulto Jovem , Fosfocreatina/metabolismoRESUMO
BACKGROUND: Chronic migraine is closely related to the dysregulation of neurochemical substances in the brain, with metabolic imbalance being one of the proposed causes of chronic migraine. This study aims to evaluate the metabolic changes between energy metabolism and excitatory and inhibitory neurotransmitters in key brain regions of mice with chronic migraine-like state and to uncover the dysfunctional pathways of migraine. METHODS: A chronic migraine-like state mouse model was established by repeated administration of nitroglycerin (NTG). We used von Frey filaments to assess the mechanical thresholds of the hind paw and periorbital in wild-type and familial hemiplegic migraine type 2 mice. After the experiments, tissue was collected from five brain regions: the somatosensory cortex (SSP), hippocampus, thalamus (TH), hypothalamus, and the spinal trigeminal nucleus caudalis (TNC). Proton magnetic resonance spectroscopy (1H-MRS) was employed to study the changes in brain metabolites associated with migraine, aiming to explore the mechanisms underlying metabolic imbalance in chronic migraine-like state. RESULTS: In NTG-induced chronic migraine-like state model, we observed a significant reduction in energy metabolism during central sensitization, an increase in excitatory neurotransmitters such as glutamate, and a tendency for inhibitory neurotransmitters like GABA to decrease. The TNC and thalamus were the most affected regions. Furthermore, the consistency of N-acetylaspartate levels highlighted the importance of the TNC-TH-SSP pathway in the ascending nociceptive transmission of migraine. CONCLUSION: Abnormal energy metabolism and neurotransmitter imbalance in the brain region of NTG-induced chronic migraine-like state model are crucial mechanisms contributing to the chronicity of migraine.
Assuntos
Modelos Animais de Doenças , Metabolismo Energético , Transtornos de Enxaqueca , Nitroglicerina , Animais , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Transtornos de Enxaqueca/metabolismo , Transtornos de Enxaqueca/induzido quimicamente , Nitroglicerina/farmacologia , Nitroglicerina/toxicidade , Camundongos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/diagnóstico por imagem , Espectroscopia de Prótons por Ressonância Magnética , Masculino , Camundongos Endogâmicos C57BL , Vasodilatadores/farmacologia , Doença CrônicaRESUMO
In vivo proton (1H) magnetic resonance spectroscopy (MRS) is a powerful non-invasive method that can measure Alzheimer's disease (AD)-related neuropathological alterations at the molecular level. AD biomarkers include amyloid-beta (Aß) plaques and hyperphosphorylated tau neurofibrillary tangles. These biomarkers can be detected via postmortem analysis but also in living individuals through positron emission tomography (PET) or biofluid biomarkers of Aß and tau. This review offers an overview of biochemical abnormalities detected by 1H MRS within the biologically defined AD spectrum. It includes a summary of earlier studies that explored the association of 1H MRS metabolites with biofluid, PET, and postmortem AD biomarkers and examined how apolipoprotein e4 allele carrier status influences brain biochemistry. Studying these associations is crucial for understanding how AD pathology affects brain homeostasis throughout the AD continuum and may eventually facilitate the development of potential novel therapeutic approaches.
Assuntos
Doença de Alzheimer , Biomarcadores , Tomografia por Emissão de Pósitrons , Espectroscopia de Prótons por Ressonância Magnética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Humanos , Tomografia por Emissão de Pósitrons/métodos , Biomarcadores/metabolismo , Espectroscopia de Prótons por Ressonância Magnética/métodos , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Genótipo , Proteínas tau/metabolismo , Proteínas tau/genética , Peptídeos beta-Amiloides/metabolismoRESUMO
To improve exercise performance, the supplement of nutrients has become a common practice before prolonged exercise. Trimethylamine N-oxide (TMAO) has been shown to ameliorate oxidative stress damage, which may be beneficial in improving exercise capacity. Here, we assessed the effects of TMAO on mice with exhaustive swimming, analyzed the metabolic changes, and identified significantly altered metabolic pathways of skeletal muscle using a nuclear magnetic resonance-based (NMR-based) metabolomics approach to uncover the effects of TMAO improving exercise performance of mice. We found that TMAO pre-administration markedly prolonged the exhaustive time in mice. Further investigation showed that TMAO pre-administration increased levels of 3-hydroxybutyrate, isocitrate, anserine, TMA, taurine, glycine, and glutathione and disturbed the three metabolic pathways related to oxidative stress and protein synthesis in skeletal muscle. Our results provide a metabolic mechanistic understanding of the effects of TMAO supplements on the exercise performance of skeletal muscle in mice. This work may be beneficial in exploring the potential of TMAO to be applied in nutritional supplementation to improve exercise performance. This work will lay a scientific foundation and be beneficial to exploring the potential of TMAO to apply in nutritional supplementation.
Assuntos
Metabolômica , Metilaminas , Músculo Esquelético , Condicionamento Físico Animal , Animais , Metilaminas/metabolismo , Metilaminas/farmacologia , Camundongos , Metabolômica/métodos , Músculo Esquelético/metabolismo , Músculo Esquelético/efeitos dos fármacos , Masculino , Metaboloma/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espectroscopia de Prótons por Ressonância Magnética , NataçãoRESUMO
Mitragyna speciosa is a perennial plant native to Asia, well known for its psychoactive properties. Its major alkaloid mitragynine is known to have sedative and euphoric effects. Hence, the plant has been a subject of abuse, leading to addiction, necessitating efficient analytical methods to detect its psychoactive constituents. However, current chromatography-based methods for detecting the alkaloids are time consuming and costly. Quantitative nuclear magnetic resonance (qNMR) spectroscopy emerges as a promising alternative due to its nondestructive nature, structural insights, and short analysis time. Hence, a rapid and precise qNMR method was developed to quantify selected major psychoactive alkaloids in various parts of M. speciosa. Mitragynine, specioliatine, and speciogynine were quantified in relation to the integral value of the -OCH3 groups of the alkaloids and the internal standard 1,4-dinitrobenzene. The precision and reproducibility of the method gave a relative standard deviation (RSD) of 2%, demonstrating the reliability of the method. In addition, the method showed excellent specificity, sensitivity, high linearity range (R2 = 0.999), and limits of detection (LOD) and quantification (LOQ) values. The analysis revealed that the red-veined M. speciosa leaves contained higher levels of mitragynine (32.34 mg/g), specioliatine (16.84 mg/g) and speciogynine (7.69 mg/g) compared to the green-veined leaves, stem bark, or fruits.
Assuntos
Alcaloides , Mitragyna , Mitragyna/química , Alcaloides/análise , Alcaloides/química , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Alcaloides de Triptamina e Secologanina/análise , Alcaloides de Triptamina e Secologanina/química , Estrutura Molecular , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The neurobiological underpinnings of Autism Spectrum Disorder (ASD) are diverse and likely multifactorial. One possible mechanism is increased oxidative stress leading to altered neurodevelopment and brain function. However, this hypothesis has mostly been tested in post-mortem studies. So far, available in vivo studies in autistic individuals have reported no differences in glutathione (GSH) levels in frontal, occipital, and subcortical regions. However, these studies were limited by the technically challenging quantification of GSH, the main brain antioxidant molecule. This study aimed to overcome previous studies' limitations by using a GSH-tailored spectroscopy sequence and optimised quantification methodology to provide clarity on GSH levels in autistic adults. METHODS: We used spectral editing proton-magnetic resonance spectroscopy (1H-MRS) combined with linear combination model fitting to quantify GSH in the dorsomedial prefrontal cortex (DMPFC) and medial occipital cortex (mOCC) of autistic and non-autistic adults (male and female). We compared GSH levels between groups. We also examined correlations between GSH and current autism symptoms, measured using the Autism Quotient (AQ). RESULTS: Data were available from 31 adult autistic participants (24 males, 7 females) and 40 non-autistic participants (21 males, 16 females); the largest sample to date. The GSH levels did not differ between groups in either region. No correlations with AQ were observed. CONCLUSION: GSH levels as measured using 1H-MRS are unaltered in the DMPFC and mOCC regions of autistic adults, suggesting that oxidative stress in these cortical regions is not a marked neurobiological signature of ASD.
Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Glutationa , Lobo Occipital , Humanos , Masculino , Feminino , Glutationa/metabolismo , Glutationa/análise , Adulto , Lobo Occipital/metabolismo , Lobo Occipital/diagnóstico por imagem , Transtorno do Espectro Autista/metabolismo , Transtorno Autístico/metabolismo , Adulto Jovem , Espectroscopia de Prótons por Ressonância Magnética , Lobo Frontal/metabolismo , Estresse Oxidativo , Pessoa de Meia-Idade , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/diagnóstico por imagemRESUMO
This study introduces a new NMR-based methodology for identification (ID) and quantification (purity, strength) assays of widely used amino acids. A detailed analysis of four amino acids and their available salts was performed with both a high-field (600â¯MHz) and a benchtop (60â¯MHz) NMR instrument. To assess sensitivity constraints, samples for 1H NMR analysis were initially prepared using only 10â¯mg of analyte and 1â¯mg of maleic acid (MA) as an internal calibrant (IC) and secondary chemical shift reference. The characteristic dispersion of the peak patterns indicating the presence or absence of a counterion (mostly chloride) was conserved at both high and low-field strength instruments, showing that the underlying NMR spectroscopic parameters, i.e., chemical shifts and coupling constants, are independent of the magnetic field strength. However, as the verbal descriptions of 1H NMR spectra are challenging in the context of reference materials and pharmaceutical monographs, an alternative method for the identification (ID) of amino acids is proposed that uses 13C NMR patterns from multiplicity-edited HSQC (ed-HSQC), which are both compound-specific and straightforward to document. For ed-HSQC measurements, the sample amount was increased to 30â¯mg of the analyte and several acquisition parameters were tested, including t1 increments used in the pulse program, number of scans, and repetition time. Excellent congruence with deviations <0.1â¯ppm was achieved for the 13C chemical shifts from 1D 13C NMR spectra (150â¯MHz) vs. those extracted from ed-HSQC (15â¯MHz traces). Finally, all samples of amino acid candidate reference materials were quantified by 1H qNMR (abs-qHNMR) at both 600 and 60â¯MHz. At high field, both IC and relative quantitations were performed, however, with the low-field instrument, only the IC method was used. The results showed that the analyzed reference material candidates were generally highly pure compounds. To achieve adequately low levels of uncertainty for such high-purity materials, the sample amounts were increased to 100â¯mg of analytes and 10â¯mg of the IC and replicates were analyzed for selected amino acids.
Assuntos
Aminoácidos , Espectroscopia de Ressonância Magnética , Aminoácidos/análise , Aminoácidos/química , Espectroscopia de Ressonância Magnética/métodos , Padrões de Referência , Calibragem , Espectroscopia de Prótons por Ressonância Magnética/métodos , Maleatos/química , Maleatos/análiseRESUMO
PURPOSE OF REVIEW: Proton nuclear magnetic resonance (NMR) can rapidly assess lipoprotein concentrations and sizes in biological samples. It may be especially useful for quantifying high-density lipoprotein (HDL), which exhibits diverse particle sizes and concentrations. We provide a critical review of the strengths and limitations of NMR for quantifying HDL subclasses. RECENT FINDINGS: Recent studies using NMR have shed light on HDL's role in various disorders, ranging from residual cardiovascular risk to host susceptibility to infection. However, accurately quantifying HDL particle number, size, and concentration (HDL-P) remains a challenge. Discrepancies exist between NMR and other methods such as gel electrophoresis, ion mobility analysis and size-exclusion chromatography in estimating the abundance of HDL species and the ratio of apolipoprotein A-I (APOA1) to HDL particles. SUMMARY: NMR is a low-cost method for quantifying HDL-P that is readily applicable to clinical and translational studies. However, inconsistencies between the results of NMR quantification of HDL-P and other independent methods hinder the interpretation of NMR results. Because proton NMR apparently fails to accurately quantify the sizes and concentrations of HDL, the relevance of such studies to HDL biology poses challenges. This limits our understanding of pathophysiological implications of HDL-P as determined by NMR, particularly in determining cardiovascular disease (CVD) risk.
Assuntos
Lipoproteínas HDL , Humanos , Lipoproteínas HDL/sangue , Lipoproteínas HDL/metabolismo , Lipoproteínas HDL/química , Animais , Espectroscopia de Prótons por Ressonância Magnética/métodos , Tamanho da Partícula , Espectroscopia de Ressonância Magnética/métodosRESUMO
Total amount of creatine (Cr) and phosphocreatine, or total creatine (tCr), may have a significant impact on the performance of skeletal muscles. In sports such as bodybuilding, it is popular to take Cr supplements to maintain tCr level. However, no study has explored the quantitative relationship between exercise intensity and the induced change in muscle's tCr. In this well-controlled study, straight-leg plantar flexion with specific load and duration was performed by 10 healthy subjects inside an MRI scanner, immediately followed by 1H MR spectroscopy (MRS) for measuring tCr concentration in gastrocnemius. For repeatability assessment, the experiment was repeated for each subject on two different days. Across all the subjects, baseline tCr was 46.6 ± 2.4 mM, ranging from 40.6 to 50.1 mM; with exercise, tCr significantly decreased by 10.9% ± 1.0% with 6-lb load and 21.0% ± 1.3% with 12-lb load (p < 0.0001). Between two different days, baseline tCr, percentage decrease induced by exercise with a 6-lb and 12-lb load differed by 2.2% ± 2.3%, 11.7% ± 6.0% and 4.9% ± 3.2%, respectively. In conclusion, the proposed protocol of controlled exercise stimulation and MRS acquisition can reproducibly monitor tCr level and its exercise-induced change in skeletal muscles. The measured tCr level is sensitive to exercise intensity, so can be used to quantitatively assess muscle performance or fatigue.
Assuntos
Creatina , Exercício Físico , Músculo Esquelético , Humanos , Creatina/metabolismo , Masculino , Adulto , Exercício Físico/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Projetos Piloto , Feminino , Espectroscopia de Ressonância Magnética/métodos , Adulto Jovem , Fosfocreatina/metabolismo , Espectroscopia de Prótons por Ressonância Magnética/métodosRESUMO
INTRODUCTION: Breeding for oil palm resistance against basal stem rot caused by Ganoderma boninense is challenging and time-consuming. Advanced oil palm gene pools are very limited, hence it is assumed that parental palms have experienced genetic drift and lost their resistance genes against Ganoderma. High-throughput selection criteria should be developed. Metabolomic analysis using 1H nuclear magnetic resonance (NMR) spectroscopy is easy, and the resulting metabolite can be used as a diagnostic tool for detecting disease in various host-pathogen combinations. OBJECTIVES: The objective of this study was to identify metabolite variations in Dura (D) and Pisifera (P) parental palms with different resistance levels against Ganoderma and moderately resistant DxP using 1H NMR analysis. METHODS: Leaf tissues of seven different oil palm categories consisting of: resistant, moderate, and susceptible Dura (D); moderate and susceptible Pisifera (P); resistant Tenera/Pisifera (T/P) parental palms; and moderately resistant DxP variety progenies, were sampled and their metabolites were determined using NMR spectroscopy. RESULTS: Twenty-nine types of metabolites were identified, and most of the metabolites fall in the monosaccharides, amino acids, and fatty acids compound classes. The PCA, PLS-DA, and heatmap multivariate analysis indicated two identified groups of resistance based on their metabolites. The first group consisted of resistant T/P, moderate P, resistant D, and moderately resistant DxP. In contrast, the second group consisted of susceptible P, moderate D, and susceptible D. Glycerol and ascorbic acid were detected as biomarker candidates by OPLS-DA to differentiate moderately resistant DxP from susceptible D and P. The pathway analysis suggested that glycine, serine, and threonine metabolism and taurine and hypotaurine metabolism were involved in the oil palm defense mechanism against Ganoderma. CONCLUSION: A metabolomic study with 1H NMR was able to describe the metabolite composition that could differentiate the characteristics of oil palm resistance against basal stem rot (BSR) caused by G. boninense. These metabolites revealed in this study have enormous potential to become support tools for breeding new oil palm varieties with higher resistance against BSR.
Assuntos
Arecaceae , Resistência à Doença , Ganoderma , Metabolômica , Doenças das Plantas , Folhas de Planta , Ganoderma/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/química , Doenças das Plantas/microbiologia , Arecaceae/metabolismo , Arecaceae/química , Metabolômica/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , MetabolomaAssuntos
Aspirina , Fígado , Hepatopatia Gordurosa não Alcoólica , Humanos , Aspirina/administração & dosagem , Fígado/diagnóstico por imagem , Fígado/efeitos dos fármacos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Metabolismo dos Lipídeos/efeitos dos fármacosRESUMO
1H-1H nuclear cross-relaxation experiments have been carried out with lysozyme in variable glycerol viscosity to study intramolecular motion, self-diffusion, and isotropic rigid-body rotational tumbling at 298 K, pH 3.8. Dynamics of intramolecular 1H-1H cross-relaxation rates, the increase in internuclear spatial distances, and lateral and rotational diffusion coefficients all show fractional viscosity dependence with a power law exponent κ in the 0.17-0.83 range. The diffusion coefficient of glycerol Ds with the bulk viscosity itself is non-Stokesian, having a fractional viscosity dependence on the medium viscosity (Ds ⼠η-κ, κ ≈ 0.71). The concurrence and close similarity of the fractional viscosity dependence of glycerol diffusion on the one hand, and diffusion and intramolecular cross-relaxation rates of the protein on the other lead to infer that relaxation of glycerol slaves protein relaxations. Glycerol-transformed native lysozyme to a quasi-native state does not affect the conclusion that both global and internal fluctuations are slaved to glycerol relaxation.
Assuntos
Glicerol , Muramidase , Muramidase/química , Muramidase/metabolismo , Glicerol/química , Viscosidade , Espectroscopia de Prótons por Ressonância Magnética , Ressonância Magnética Nuclear Biomolecular , Difusão , Animais , GalinhasRESUMO
Metabolomics has emerged as a powerful tool for identifying biomarkers of disease, and nuclear magnetic resonance (NMR) spectroscopy allows for the simultaneous detection of a wide range of metabolites. However, due to complex interactions within metabolic networks, metabolites often exhibit high correlation and collinearity. To address this challenge, self-organizing maps (SOMs) of Kohonen maps and counter propagation-artificial neural networks (CP-ANN) were employed in this study to model proton nuclear magnetic resonance spectroscopic (1HNMR) data from control samples and breast cancer (BC) patients. Blood serum samples from a control group (n=24) and BC patients (n=18) were used to extract metabolites using methanol and chloroform solvents in optimum extraction conditions. The 1HNMR data was preprocessed by performing phase, baseline, and shift corrections. Subsequently, the preprocessed data was modeled using Kohonen network as an unsupervised technique and CP-ANN as a supervised technique. In this regard, the model built with CP-ANN successfully distinguished between the two classes with an accuracy of 100â¯% for both group and sensitivity of 96â¯% and 100â¯% for control group and BC patients, respectively. Additionally, CP-ANN algorithm demonstrated predictive capabilities by accurately classifying test samples with 90â¯% sensitivity, 98â¯% specificity, and 96â¯% accuracy for control group and 100â¯% sensitivity, 90â¯% specificity, and 96â¯% accuracy for BC patients. Furthermore, analysis of the resulting topological map revealed 14 significant variables (biomarkers) such as sarcosine, lysine, trehalose, tryptophan, and betaine that effectively differentiated between healthy individuals and BC patients.
Assuntos
Neoplasias da Mama , Metabolômica , Redes Neurais de Computação , Humanos , Neoplasias da Mama/metabolismo , Feminino , Metabolômica/métodos , Pessoa de Meia-Idade , Adulto , Algoritmos , Biomarcadores Tumorais/sangue , Espectroscopia de Ressonância Magnética/métodos , Estudos de Casos e Controles , Sensibilidade e Especificidade , Espectroscopia de Prótons por Ressonância Magnética/métodosRESUMO
PURPOSE: Retrospective frequency-and-phase correction (FPC) methods attempt to remove frequency-and-phase variations between transients to improve the quality of the averaged MR spectrum. However, traditional FPC methods like spectral registration struggle at low SNR. Here, we propose a method that directly integrates FPC into a 2D linear-combination model (2D-LCM) of individual transients ("model-based FPC"). We investigated how model-based FPC performs compared to the traditional approach, i.e., spectral registration followed by 1D-LCM in estimating frequency-and-phase drifts and, consequentially, metabolite level estimates. METHODS: We created synthetic in-vivo-like 64-transient short-TE sLASER datasets with 100 noise realizations at 5 SNR levels and added randomly sampled frequency and phase variations. We then used this synthetic dataset to compare the performance of 2D-LCM with the traditional approach (spectral registration, averaging, then 1D-LCM). Outcome measures were the frequency/phase/amplitude errors, the SD of those ground-truth errors, and amplitude Cramér Rao lower bounds (CRLBs). We further tested the proposed method on publicly available in-vivo short-TE PRESS data. RESULTS: 2D-LCM estimates (and accounts for) frequency-and-phase variations directly from uncorrected data with equivalent or better fidelity than the conventional approach. Furthermore, 2D-LCM metabolite amplitude estimates were at least as accurate, precise, and certain as the conventionally derived estimates. 2D-LCM estimation of FPC and amplitudes performed substantially better at low-to-very-low SNR. CONCLUSION: Model-based FPC with 2D linear-combination modeling is feasible and has great potential to improve metabolite level estimation for conventional and dynamic MRS data, especially for low-SNR conditions, for example, long TEs or strong diffusion weighting.
Assuntos
Algoritmos , Encéfalo , Razão Sinal-Ruído , Humanos , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Modelos Lineares , Processamento de Imagem Assistida por Computador/métodos , Espectroscopia de Prótons por Ressonância Magnética/métodos , Estudos Retrospectivos , Imageamento por Ressonância Magnética/métodosRESUMO
The present study proposes the development of new wine recognition models based on Artificial Intelligence (AI) applied to the mid-level data fusion of 1H NMR and Raman data. In this regard, a supervised machine learning method, namely Support Vector Machines (SVMs), was applied for classifying wine samples with respect to the cultivar, vintage, and geographical origin. Because the association between the two data sources generated an input space with a high dimensionality, a feature selection algorithm was employed to identify the most relevant discriminant markers for each wine classification criterion, before SVM modeling. The proposed data processing strategy allowed the classification of the wine sample set with accuracies up to 100% in both cross-validation and on an independent test set and highlighted the efficiency of 1H NMR and Raman data fusion as opposed to the use of a single-source data for differentiating wine concerning the cultivar and vintage.
Assuntos
Análise Espectral Raman , Máquina de Vetores de Suporte , Vinho , Vinho/análise , Análise Espectral Raman/métodos , Inteligência Artificial , Espectroscopia de Prótons por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodosRESUMO
Tobacco smoking is highly prevalent among patients with psychosis and associated with worse clinical outcomes. Neurometabolites, such as glutamate and choline, are both implicated in psychosis and tobacco smoking. However, the specific associations between smoking and neurometabolites have yet to be investigated in patients with psychosis. The current study examines associations of chronic smoking and neurometabolite levels in the anterior cingulate cortex (ACC) in first-episode psychosis (FEP) patients and controls. Proton magnetic resonance spectroscopy (1H MRS) data of 59 FEP patients and 35 controls were analysed. Associations between smoking status (i.e., smoker yes/no) or cigarettes per day and Glx (glutamate + glutamine, as proxy for glutamate) and total choline (tCh) levels were assessed at baseline in both groups separately. For patients, six months follow-up data were acquired for multi-cross-sectional analysis using linear mixed models. No significant differences in ACC Glx levels were found between smoking (n = 28) and non-smoking (n = 31) FEP patients. Smoking patients showed lower tCh levels compared to non-smoking patients at baseline, although not surving multiple comparisons correction, and in multi-cross-sectional analysis (pFDR = 0.08 and pFDR = 0.044, respectively). Negative associations were observed between cigarettes smoked per day, and ACC Glx (pFDR = 0.02) and tCh levels (pFDR = 0.02) in controls. Differences between patients and controls regarding Glx might be explained by pre-existing disease-related glutamate deficits or alterations at nicotine acetylcholine receptor level, resulting in differences in tobacco-related associations with neurometabolites. Additionally, observed alterations in tCh levels, suggesting reduced cellular proliferation processes, might result from exposure to the neurotoxic effects of smoking.
Assuntos
Colina , Ácido Glutâmico , Giro do Cíngulo , Espectroscopia de Prótons por Ressonância Magnética , Transtornos Psicóticos , Fumar Tabaco , Humanos , Giro do Cíngulo/metabolismo , Giro do Cíngulo/diagnóstico por imagem , Transtornos Psicóticos/metabolismo , Masculino , Feminino , Adulto , Colina/metabolismo , Adulto Jovem , Estudos de Casos e Controles , Ácido Glutâmico/metabolismo , Seguimentos , Fumar Tabaco/metabolismo , Glutamina/metabolismo , Estudos Transversais , AdolescenteRESUMO
Objective: To investigate the performance of diffusion-tensor imaging (DTI) and hydrogen proton magnetic resonance spectroscopy (1H-MRS) parameters in predicting the immunohistochemistry (IHC) biomarkers of glioma. Methods: Patients with glioma confirmed by pathology from March 2015 to September 2019 were analyzed, the preoperative DTI and 1H-MRS images were collected, apparent diffusion coefficient (ADC) and fractional anisotropy (FA), in the lesion area were measured, the relative values relative ADC (rADC) and relative FA (rFA) were obtained by the ratio of them in the lesion area to the contralateral normal area. The peak of each metabolite in the lesion area of 1H-MRS image: N-acetylaspartate (NAA), choline (Cho), and creatine (Cr), and metabolite ratio: NAA/Cho, NAA/(Cho + Cr) were selected and calculated. The preoperative IHC data were collected including CD34, Ki-67, p53, S-100, syn, vimentin, NeuN, Nestin, and glial fibrillary acidic protein. Results: One predicting parameter of DTI was screened, the rADC of the Ki-67 positive group was lower than that of the negative group. Two parameters of 1H-MRS were found to have significant reference values for glioma grades, the NAA and Cr decreased as the grade of glioma increased, moreover, Ki-67 Li was negatively correlated with NAA and Cr. Conclusion: NAA and Cr have potential application value in predicting glioma grades and tumor proliferation activity. Only rADC has predictive value for Ki-67 expression among DTI parameters.
Assuntos
Neoplasias Encefálicas , Glioma , Imuno-Histoquímica , Humanos , Glioma/diagnóstico por imagem , Glioma/patologia , Glioma/metabolismo , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Imagem de Tensor de Difusão/métodos , Imageamento por Ressonância Magnética/métodos , Idoso , Espectroscopia de Prótons por Ressonância Magnética/métodos , Adulto JovemRESUMO
BACKGROUND: Angelman syndrome (AS) is a rare neurodevelopmental genetic disorder caused by the loss of function of the ubiquitin ligase E3A (UBE3A) gene, affecting approximately 1:15,000 live births. We have recently shown that mitochondrial function in AS is altered during mid to late embryonic brain development leading to increased oxidative stress and enhanced apoptosis of neural precursor cells. However, the overall alterations of metabolic processes are still unknown. Hence, as a follow-up, we aim to investigate the metabolic profiles of wild-type (WT) and AS littermates and to identify which metabolic processes are aberrant in the brain of AS model mice during embryonic development. METHODS: We collected brain tissue samples from mice embryos at E16.5 and performed metabolomic analyses using proton nuclear magnetic resonance (1H-NMR) spectroscopy. Multivariate and Univariate analyses were performed to determine the significantly altered metabolites in AS mice. Pathways associated with the altered metabolites were identified using metabolite set enrichment analysis. RESULTS: Our analysis showed that overall, the metabolomic fingerprint of AS embryonic brains differed from those of their WT littermates. Moreover, we revealed a significant elevation of distinct metabolites, such as acetate, lactate, and succinate in the AS samples compared to the WT samples. The elevated metabolites were significantly associated with the pyruvate metabolism and glycolytic pathways. LIMITATIONS: Only 14 metabolites were successfully identified and investigated in the present study. The effect of unidentified metabolites and their unresolved peaks was not determined. Additionally, we conducted the metabolomic study on whole brain tissue samples. Employing high-resolution NMR studies on different brain regions could further expand our knowledge regarding metabolic alterations in the AS brain. Furthermore, increasing the sample size could reveal the involvement of more significantly altered metabolites in the pathophysiology of the AS brain. CONCLUSIONS: Ube3a loss of function alters bioenergy-related metabolism in the AS brain during embryonic development. Furthermore, these neurochemical changes could be linked to the mitochondrial reactive oxygen species and oxidative stress that occurs during the AS embryonic development.
Assuntos
Síndrome de Angelman , Encéfalo , Modelos Animais de Doenças , Metabolômica , Espectroscopia de Prótons por Ressonância Magnética , Animais , Síndrome de Angelman/metabolismo , Síndrome de Angelman/genética , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Camundongos , Metaboloma , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , FemininoRESUMO
The specific spatial and temporal distribution of lipids in membranes play a crucial role in determining the biochemical and biophysical properties of the system. In nature, the asymmetric distribution of lipids is a dynamic process with ATP-dependent lipid transporters maintaining asymmetry, and passive transbilayer diffusion, that is, flip-flop, counteracting it. In this chapter, two probe-free techniques, 1H NMR and time-resolved small angle neutron scattering, are described in detail as methods of investigating lipid flip-flop rates in synthetic liposomes that have been generated with an asymmetric bilayer composition.