1H NMR Spectroscopy

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Anna Midelfart - One of the best experts on this subject based on the ideXlab platform.

  • Effect of UV-A and UV-B irradiation on the metabolic profile of aqueous humor in rabbits analyzed by 1H NMR Spectroscopy.
    Investigative ophthalmology & visual science, 2005
    Co-Authors: May-britt Tessem, Tone Frost Bathen, Jitka Cejkova, Anna Midelfart
    Abstract:

    Effect of UV-A and UV-B Irradiation on the Metabolic Profile of Aqueous Humor in Rabbits Analyzed by 1H NMR Spectroscopy

  • Detection of different metabolites in the rabbit lens by high resolution 1H NMR Spectroscopy
    Current eye research, 1996
    Co-Authors: Anna Midelfart, Anne Dybdahl, Ingrid S. Gribbestad
    Abstract:

    Purpose. To investigate the metabolic profile of the rabbit lens using high resolution 1H NMR Spectroscopy including two-dimensional shift correlated (COSY) technique.Methods. Perchloric acid extracts of the rabbit lens were analysed with a Bruker AM-500 spectrometer and the metabolites were assigned in the spectra. Some of these were also quantified.Results. More than 20 metabolites were detected in the perchloric acid extract of a single lens, including amino acids, nucleotides and other related compounds. Of particular importance is the ability to detect and identify glutathione, myo-inositol, scyllo-inositol and taurine.Conclusions. The study demonstrated the potential of 1H NMR Spectroscopy for monitoring the metabolic profile of the lens in normal and pathologic conditions.

  • High-resolution 1H NMR Spectroscopy of aqueous humour from rabbits
    Graefes Archive for Clinical and Experimental Ophthalmology, 1994
    Co-Authors: Ingrid S. Gribbestad, Anna Midelfart
    Abstract:

    ⊎ Background: Detection of different substances in aqueous humour is important for evaluation of the disorders affecting the eye. The purpose of the present study was to apply highresolution proton (1H) nuclear magnetic resonance (NMR) Spectroscopy for extensive characterisation of the metabolites in the aqueous humour from rabbits. ⊎ Methods: High-resolution 1H NMR Spectroscopy, including two-dimensional shift correlated (COSY) technique, was performed on aqueous humour from rabbits. ⊎ Results: More than 20 metabolites were simultaneously detected and identified in high-resolution 1H NMR spectra of aqueous humour from rabbits. Some of these were also quantified. ⊎ Conclusion: High-resolution 1H NMR Spectroscopy is a valuable method for simultaneous detection of many different metabolites in aqueous humour.

Yoshio Nosaka - One of the best experts on this subject based on the ideXlab platform.

  • Photocatalytic Reaction Sites at the TiO2 Surface as Studied by Solid-State 1H NMR Spectroscopy
    Langmuir, 2003
    Co-Authors: Atsuko Y. Nosaka, Toshimichi Fujiwara, Hiromasa Yagi, And Hideo Akutsu, Yoshio Nosaka
    Abstract:

    The adsorption and photodecomposition of ethanol that was employed as a model substrate of organic pollutants were investigated in the presence of adsorbed water with TiO2 by solid-state 1H NMR Spectroscopy in order to obtain information about the actual photocatalytic reaction sites of organic pollutants on TiO2 photocatalysts. Consequently it was revealed that ethanol molecules in practical conditions as contaminants were firmly captured in mobile physisorbed water layers to be photodecomposed to CO2 and water after photoillumination, suggesting that actual photocatalytic reactions should proceed in physisorbed water layers.

  • Photoinduced Changes of Adsorbed Water on a TiO2 Photocatalytic Film As Studied by 1H NMR Spectroscopy
    The Journal of Physical Chemistry B, 2003
    Co-Authors: Atsuko Y. Nosaka, Toshimichi Fujiwara, Hiromasa Yagi, And Hideo Akutsu, Eiichi Kojima, Yoshio Nosaka
    Abstract:

    The enhancement of the signal intensity of water molecularly adsorbed on TiO2 films could be observed on UV irradiation by 1H NMR Spectroscopy, which has been difficult to elucidate so far with alternative spectroscopic techniques such as X-ray photoelectron Spectroscopy (XPS), temperature programmed desorption (TPD), and infrared reflection absorption Spectroscopy (IRAS). It was also confirmed that the enhanced NMR signals resulted from the photoinduced hydrophilic conversion of the film surface decreased back to the original state with the recovery to the less hydrophilic state of the TiO2 film surface when the film was kept in the dark.

Julian L. Griffin - One of the best experts on this subject based on the ideXlab platform.

  • High-Resolution Magic Angle Spinning 1H NMR Spectroscopy and Reverse Transcription-PCR Analysis of Apoptosis in a Rat Glioma
    Analytical chemistry, 2006
    Co-Authors: Julian L. Griffin, Cherie Blenkiron, Piia Valonen, Carlos Caldas, Risto A. Kauppinen
    Abstract:

    The functional genomic approaches of transcriptomics, proteomics and metabolomics aim to measure the mRNA, protein or metabolite complement of a cell, tissue or organism. In this study we have investigated the compatibility of transcriptional analysis, using Reverse Transcription (RT)-PCR, and metabolite analysis, by high-resolution magic angle spinning (HRMAS) 1H NMR Spectroscopy, in BT4C rat glioma following the induction of programmed cell death. The metabolite and transcriptional changes that accompanied apoptosis were examined at 0, 4 and 8 days of ganciclovir/thymidine kinase gene therapy. Despite the high spinning speeds employed during HRMAS 1H NMR Spectroscopy of one-half of the tumor samples, RT-PCR analysis of the pro-apoptotic transcripts Bcl-2, BAK-1, caspase-9 and FAS was possible, producing similar results to those detected in the unspun half of the tumors. Furthermore, the expression of FAS was inversely correlated with some of the key metabolic changes across the time period examined incl...

  • High‐resolution diffusion and relaxation‐edited magic angle spinning 1H NMR Spectroscopy of intact liver tissue
    Magnetic resonance in medicine, 2003
    Co-Authors: O.m. Rooney, Jeremy K. Nicholson, J. Troke, Julian L. Griffin
    Abstract:

    High-resolution magic angle spinning (HRMAS) 1H NMR Spectroscopy is ideal for monitoring the metabolic environment within tissues, particularly when spectra are weighted by physical properties such as T1 and T2 relaxation times and apparent diffusion coefficients (ADCs). In this study, spectral-editing using T1 and T2 relaxation times and ADCs at variable diffusion times was used in conjunction with HRMAS 1H NMR Spectroscopy at 14.1 T in liver tissue. To enhance the sensitivity of ADC measurements to low molecular weight metabolites a T2 spin echo was included in a standard stimulated gradient spin-echo sequence. Fatty liver induced in rats by chronic orotic acid feeding was investigated using this modified sequence. An increase in the combined ADC for the co-resonant peaks glucose, betaine, and TMAO during fatty liver disease was detected (ADCs = 0.60 ± 0.11 and 0.35 ± 0.1 * 10−9 m2s−1 (n = 3) for rats fed with and without orotic acid), indicative of a reduction in glucose and betaine and an increase in TMAO. Magn Reson Med 50:925–930, 2003. © 2003 Wiley-Liss, Inc.

Jeremy K. Nicholson - One of the best experts on this subject based on the ideXlab platform.

  • metabotyping of long lived mice using 1H NMR Spectroscopy
    Journal of Proteome Research, 2012
    Co-Authors: Anisha Wijeyesekera, Jeremy K. Nicholson, Colin Selman, Richard H Barton, Elaine Holmes, Dominic J Withers
    Abstract:

    Significant advances in understanding aging have been achieved through studying model organisms with extended healthy lifespans. Employing 1H NMR Spectroscopy, we characterized the plasma metabolic phenotype (metabotype) of three long-lived murine models: 30% dietary restricted (DR), insulin receptor substrate 1 null (Irs1–/–), and Ames dwarf (Prop1df/df). A panel of metabolic differences were generated for each model relative to their controls, and subsequently, the three long-lived models were compared to one another. Concentrations of mobile very low density lipoproteins, trimethylamine, and choline were significantly decreased in the plasma of all three models. Metabolites including glucose, choline, glycerophosphocholine, and various lipids were significantly reduced, while acetoacetate, d-3-hydroxybutyrate and trimethylamine-N-oxide levels were increased in DR compared to ad libitum fed controls. Plasma lipids and glycerophosphocholine were also decreased in Irs1–/– mice compared to controls, as wer...

  • 1H NMR Spectroscopy-based interventional metabolic phenotyping: A cohort study of rheumatoid arthritis patients
    Journal of proteome research, 2010
    Co-Authors: Michael Brændgaard Lauridsen, Jeremy K. Nicholson, Henning Bliddal, Robin Christensen, Bente Danneskiold-samsøe, Robert M. Bennett, Hector C. Keun, John C. Lindon, Mikkel H Dorff, Jerzy W. Jaroszewski
    Abstract:

    1H NMR Spectroscopy-based metabolic phenotyping was used to identify biomarkers in the plasma of patients with rheumatoid arthritis (RA). Forty-seven patients with RA (23 with active disease at baseline and 24 in remission) and 51 healthy subjects were evaluated during a one-year follow-up with assessments of disease activity (DAS-28) and 1H NMR Spectroscopy of plasma samples. Discriminant analysis provided evidence that the metabolic profiles predicted disease severity. Cholesterol, lactate, acetylated glycoprotein, and lipid signatures were found to be candidate biomarkers for disease severity. The results also supported the link between RA and coronary artery disease. Repeated assessment using mixed linear models showed that the predictors obtained from metabolic profiles of plasma at baseline from patients with active RA were significantly different from those of patients in remission (P=0.0007). However, after 31 days of optimized therapy, the two patient groups were not significantly different (P=0.91). The metabolic profiles of both groups of RA patients were different from the healthy subjects. 1H NMR-based metabolic phenotyping of plasma samples in patients with RA is well suited for discovery of biomarkers and may be a potential approach for disease monitoring and personalized medication for RA therapy.

  • High‐resolution diffusion and relaxation‐edited magic angle spinning 1H NMR Spectroscopy of intact liver tissue
    Magnetic resonance in medicine, 2003
    Co-Authors: O.m. Rooney, Jeremy K. Nicholson, J. Troke, Julian L. Griffin
    Abstract:

    High-resolution magic angle spinning (HRMAS) 1H NMR Spectroscopy is ideal for monitoring the metabolic environment within tissues, particularly when spectra are weighted by physical properties such as T1 and T2 relaxation times and apparent diffusion coefficients (ADCs). In this study, spectral-editing using T1 and T2 relaxation times and ADCs at variable diffusion times was used in conjunction with HRMAS 1H NMR Spectroscopy at 14.1 T in liver tissue. To enhance the sensitivity of ADC measurements to low molecular weight metabolites a T2 spin echo was included in a standard stimulated gradient spin-echo sequence. Fatty liver induced in rats by chronic orotic acid feeding was investigated using this modified sequence. An increase in the combined ADC for the co-resonant peaks glucose, betaine, and TMAO during fatty liver disease was detected (ADCs = 0.60 ± 0.11 and 0.35 ± 0.1 * 10−9 m2s−1 (n = 3) for rats fed with and without orotic acid), indicative of a reduction in glucose and betaine and an increase in TMAO. Magn Reson Med 50:925–930, 2003. © 2003 Wiley-Liss, Inc.

  • 750 MHz 1H-NMR Spectroscopy of human blood plasma
    Journal of Pharmaceutical and Biomedical Analysis, 1993
    Co-Authors: Peta J. D. Foxall, Manfred Spraul, R. D. Farrant, L.c. Lindon, Gh Neild, Jeremy K. Nicholson
    Abstract:

    The application of high-resolution 750 MHz 1H-NMR Spectroscopy to a biological fluid is demonstrated for the first time and its advantages over 600 MHz 1H observation shown by reference to studies on human blood plasma. Improvements in signal dispersion were observed which facilitated improved signal assignments. Differences in lipid/lipoprotein signal line-widths between 600 and 750 MHz were noted indicating that ultrahigh field measurements may help to give insight into dynamic motional phenomena of lipids in whole plasma. The two-dimensional J-resolved (JRES) technique and spin-echo spectra measured at 750 MHz have enabled new signal assignments to be made in control plasma. The application of 750 MHz JRES to the clinical chemical problem of the detection of abnormal metabolites associated with chronic renal failure is also demonstrated.

Atsuko Y. Nosaka - One of the best experts on this subject based on the ideXlab platform.

  • Photocatalytic Reaction Sites at the TiO2 Surface as Studied by Solid-State 1H NMR Spectroscopy
    Langmuir, 2003
    Co-Authors: Atsuko Y. Nosaka, Toshimichi Fujiwara, Hiromasa Yagi, And Hideo Akutsu, Yoshio Nosaka
    Abstract:

    The adsorption and photodecomposition of ethanol that was employed as a model substrate of organic pollutants were investigated in the presence of adsorbed water with TiO2 by solid-state 1H NMR Spectroscopy in order to obtain information about the actual photocatalytic reaction sites of organic pollutants on TiO2 photocatalysts. Consequently it was revealed that ethanol molecules in practical conditions as contaminants were firmly captured in mobile physisorbed water layers to be photodecomposed to CO2 and water after photoillumination, suggesting that actual photocatalytic reactions should proceed in physisorbed water layers.

  • Photoinduced Changes of Adsorbed Water on a TiO2 Photocatalytic Film As Studied by 1H NMR Spectroscopy
    The Journal of Physical Chemistry B, 2003
    Co-Authors: Atsuko Y. Nosaka, Toshimichi Fujiwara, Hiromasa Yagi, And Hideo Akutsu, Eiichi Kojima, Yoshio Nosaka
    Abstract:

    The enhancement of the signal intensity of water molecularly adsorbed on TiO2 films could be observed on UV irradiation by 1H NMR Spectroscopy, which has been difficult to elucidate so far with alternative spectroscopic techniques such as X-ray photoelectron Spectroscopy (XPS), temperature programmed desorption (TPD), and infrared reflection absorption Spectroscopy (IRAS). It was also confirmed that the enhanced NMR signals resulted from the photoinduced hydrophilic conversion of the film surface decreased back to the original state with the recovery to the less hydrophilic state of the TiO2 film surface when the film was kept in the dark.