Automatic Quantitative analysis of HRMAS 1D proton spectra from rat liver biopsies (original) (raw)
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High-resolution magic angle spinning (HRMAS) 1 H NMR spectroscopy is ideal for monitoring the metabolic environment within tissues, particularly when spectra are weighted by physical properties such as T 1 and T 2 relaxation times and apparent diffusion coefficients (ADCs). In this study, spectral-editing using T 1 and T 2 relaxation times and ADCs at variable diffusion times was used in conjunction with HRMAS 1 H NMR spectroscopy at 14.1 T in liver tissue. To enhance the sensitivity of ADC measurements to low molecular weight metabolites a T 2 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 m 2 s -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.
750 MHz 1H and 1H-13C NMR spectroscopy of human blood plasma
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High-resolution 750 MHz lH NMR spectra of control human blood plasma have been measured and assigned by the concerted use of a range of spin-echo, twodimensional J-resolved, and homonuclear and heteronuclear (lH-13C) correlation methods. The increased spectral dispersion and sensitivity at 750 MHz enable the assignment of numerous ' H and 13C resonances from many molecular species that cannot be detected at lower frequencies. This work presents the most comprehensive assignment of the ' H NMR spectra of blood plasma yet achieved and includes the assignment of signals from 43 low M, metabolites, including many with complex or strongly coupled spin systems. New assignments are also provided from the 'H and 13C NMR signals from several important macromolecular species in whole blood plasma, i.e., very-low-density, low-density, and high-density lipoproteins, albumin, and al-acid glycoprotein. The temperature dependence of the one-dimensional and spinecho 750 MHz 'H NMRspectra of plasmawas investigated over the range 292-310 K The lH NMR signals from the h t t y acyl side chains of the lipoproteins increased substantially with temperature (hence also molecular mobility), with a disproportionate increase from lipids in low-density lipoprotein. Two-dimensional 'H-13C heteronuclear multiple quantum coherence spectroscopy at 292 and 310 K allowed both the direct detection of cholesterol and choline species bound in high-density lipoprotein and the assignment of their signals and c o h e d the assignment of most of the lipoprotein resonances.
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Magnetic Resonance in Medicine, 1987
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Nmr in Biomedicine, 2006
High-resolution magic angle spinning (HR-MAS) 1H NMR spectroscopy of intact human liver needle biopsies has not been previously reported. HR-MAS NMR spectra collected on 17 specimens with tissue amounts between ∼0.5 and 12 mg showed very good spectral resolution and signal-to-noise ratios. One-dimensional 1H spectra revealed many intense signals corresponding to cellular metabolites. In addition, some high molecular weight metabolites, such as glycogen and mobile fatty acids, could be observed in some spectra. Resonance assignments for 22 metabolites were obtained by combining the analysis of three different types of 1D 1H spectral editing, such as T2 filtering or the nuclear Overhauser effect and 2D TOCSY and 13C-HSQC spectra. Biochemical stability of the liver tissue during up to 16 h of magic angle spinning at 277 K was studied. Biochemical trends corresponding to the different pathologies were observed, involving free fragments of lipids among other metabolites. NMR signal intensity ratios can be useful for discrimination among non-pathological, hepatitis C affected and cirrhotic liver tissues. Overall, this work demonstrates the applicability of HR-MAS NMR spectroscopy to the biochemical characterization of needle biopsies of the human liver. Copyright © 2006 John Wiley & Sons, Ltd.
Analytical Biochemistry, 2000
High-resolution magic angle spinning (MAS) 1 H NMR spectroscopy has been used to investigate the biochemical composition of whole rat renal cortex and liver tissue samples. The effects of a number of sample preparation procedures and experimental variables have been investigated systematically in order to optimize spectral quality and maximize information recovery. These variables include the effects of changing the sample volume in the MAS rotor, snap-freezing the samples, and the effect of organ perfusion with deuterated saline solution prior to MAS NMR analysis. Also, the overall biochemical stability of liver and kidney tissue MAS NMR spectra was investigated under different temperature conditions. We demonstrate improved resolution and line shape of MAS NMR spectra obtained from small spherical tissue volume (12 l) rotor inserts compared to 65 l cylindrical samples directly inserted into the MAS rotors. D 2 O saline perfusion of the in situ afferent vascular tree of the tissue immediately postmortem also improves line shape in MAS NMR spectra. Snap-freezing resulted in increased signal intensities from ␣-amino acids (e.g., valine) in tissue together with decreases in renal osmolytes, such as myo-inositol. A decrease in triglyceride levels was observed in renal cortex following stasis on ice and in the MAS rotor (303 K for 4 h). This work indicates that different tissues have differential metabolic stabilities in 1 H MAS NMR experi-ments and that careful attention to sample preparation is required to minimize artifacts and maintain spectral quality.