Diffusion ordered nuclear magnetic resonance spectroscopy: principles and applications

Johnson, Charles S.

doi:10.1016/s0079-6565(99)00003-5

Cited by 1,554 publications

(725 citation statements)

References 97 publications

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“…The gradient shape factor s was set to 0.9, to account for the smoothed rectangular gradient shape used here [19]. A detailed description of the PFG-NMR method and the sequences mentioned above, is provided in several excellent reviews [20,21].…”

Section: Nuclear Magnetic Resonance Spectroscopymentioning

confidence: 99%

NMR study of the influence of pH on phenol sorption in cationic CTAB micellar solutions

Sabatino

Szczygiel

Sinnaeve

et al. 2010

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Interactions between phenol and cationic cetyltrimethylammonium bromide (CTAB) micelles have been investigated by means of nuclear magnetic resonance spectroscopy. The combined use of 1 H and NOESY techniques revealed that phenol has different preferred locations of interaction depending on the pH. At neutral pH (6.70) conditions, phenol molecules are preferentially located in the outer micelle region, at the micelle-water interface, while at more basic pH (9.94), the deprotonated phenol molecules (C 6 H 5 O -) are immersed into the palisade layer of the micelle. In addition, quantitative estimates of the solubilized fraction of phenol were obtained by using PFG-NMR. The results indicate that the phenol-CTAB interactions, although already present in neutral pH conditions, are largely favored in basic conditions as a consequence of the strong electrostatic interaction between the negatively charged phenolate ions and the positive charge of the cationic surfactant head group.(e)

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Section: Nuclear Magnetic Resonance Spectroscopymentioning

confidence: 99%

NMR study of the influence of pH on phenol sorption in cationic CTAB micellar solutions

Sabatino

Szczygiel

Sinnaeve

et al. 2010

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Diffusion ordered NMR spectroscopy is a method for the identification of different molecular weight (macro)molecules present in solution at millimolar concentrations, while the successful acquisition of the signal requires a sufficient concentration of each component [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. The method uses a special pulse-sequence to obtain a series of NMR spectra using field-gradients and is capable of determining diffusion coefficients of molecules without any concentrationgradient [19,20].…”

Section: Nih Public Accessmentioning

confidence: 99%

“…The method uses a special pulse-sequence to obtain a series of NMR spectra using field-gradients and is capable of determining diffusion coefficients of molecules without any concentrationgradient [19,20]. The intensity of the detected proton signal belonging to a particular molecular entity at a certain gradient level is dependent mostly on the rate of diffusion of that molecule as the gradient eliminates more signal intensity of molecules in faster motion.…”

Section: Nih Public Accessmentioning

confidence: 99%

Diffusion-ordered nuclear magnetic resonance spectroscopy for analysis of DNA secondary structural elements

Ambrus¹,

Yang²

2007

Analytical Biochemistry

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Structure determination of secondary DNA structural elements, such as G-quadruplexes, gains an increasing importance as fundamental physiological roles are being associated with the formation of such structures in vivo. A truncated native DNA sequence generally requires further optimization to obtain a candidate with desired NMR properties for structural analysis in solution. The optimum sequence is expected to form one dominant, stable molecular entity in solution with well-resolved NMR peaks. However, DNA sequences are prone to form structures composed of one, two, three or four strands depending on sequence and solution conditions. The thorough characterization of the molecularity (stoichiometry and molecular weight) and appropriate solution conditions for sequences with different modifications traditionally applies analytical techniques that generally do not represent the solution conditions for NMR structure determination. Here we present the application of diffusion ordered NMR spectroscopy as a useful analytical tool for the optimization and analysis of DNA secondary structural elements, specifically, the DNA G-quadruplex structures, including those formed in the human telomeric sequence and in the promoter regions of bcl-2 and c-myc genes. KeywordsDNA; NMR; DOSY; quadruplex; bcl-2; human telomere; c-myc Structural analysis of unusual DNA motifs with particular emphasis on G-quadruplexes and imotifs has a central role in the identification and characterization of molecular targets related to these structures [1][2][3][4][5][6][7]. Such structures are implicated in several physiologically important regulatory processes, with special emphasis on carcinogenesis [4][5][6][7][8][9][10][11][12]. Most of the structural studies on these elements have been performed by NMR spectroscopy. In most cases the related nucleotide sequence bearing the actual physiological function in vivo needs to be truncated/ elongated and/or mutated in order to obtain a successful candidate for NMR structure determination [3][4][5][6][7]13]. This NMR candidate should be a well-defined molecular entity in physiologically relevant solution conditions (ionic strength, pH, temperature) representing the same conformation as the original sequence. Appropriate modification of the sequence by mutation/truncation/elongation will force the molecule to form a single stable structure without altering crucial connectivities (conformation) of the structure.* To whom correspondence should be addressed at the Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 E. Mabel St., P.O. Box 210207, room 101/406, Tucson, Arizona 85721, USA; Tel: +1 520 626 6749/626 5969, Fax: +1 520 626 2466, E-mail: ambrus@pharmacy.arizona.edu, yangd@pharmacy.arizona.edu.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of ...

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“…Diffusion ordered spectroscopy (DOSY) has demonstrated enormous potential in the fields of chemistry and biochemistry (1); however, the investigation of metabolite diffusion (molecules other than water) in vivo has lagged behind due to technical challenges, such as limited signal-to-noise ratio, poor spatial resolution, pulse sequence availability, significant post-processing, lengthy acquisition times, and limited brain coverage. Despite these challenges, the pursuit of metabolite diffusion in diseased tissue is worthwhile since it may yield insights into changes in the underlying intra-cellular environment with disease (2)(3)(4)(5).…”

mentioning

confidence: 99%

Diffusion tensor spectroscopy (DTS) of human brain

Ellegood

Hanstock

Beaulieu

2005

Magnetic Resonance in Med

171

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The diffusion tensor of N-acetyl aspartate (NAA), creatine and phosphocreatine (tCr), and choline (Cho) was measured at 3T using a diffusion weighted STEAM 1 H-MRS sequence in the healthy human brain in 6 distinct regions (4 white matter and 2 cortical gray matter). The Trace/3 apparent diffusion coefficient (ADC) of each metabolite was significantly greater in white matter than gray matter. The Trace/3 ADC values of tCr and Cho were found to be significantly greater than NAA in white matter, whereas all 3 metabolites had similar Trace/3 ADC in cortical gray matter. The physical property of diffusion of water molecules has shown great utility in magnetic resonance imaging for studying a multitude of neurologic disorders, and in neurodevelopment and aging. Diffusion ordered spectroscopy (DOSY) has demonstrated enormous potential in the fields of chemistry and biochemistry (1); however, the investigation of metabolite diffusion (molecules other than water) in vivo has lagged behind due to technical challenges, such as limited signal-to-noise ratio, poor spatial resolution, pulse sequence availability, significant post-processing, lengthy acquisition times, and limited brain coverage. Despite these challenges, the pursuit of metabolite diffusion in diseased tissue is worthwhile since it may yield insights into changes in the underlying intra-cellular environment with disease (2-5).In contrast, localizing changes in water diffusion to a specific compartment of the brain has been difficult and controversial. It has long been shown that reductions in water diffusion are the most sensitive indicator of early cerebral ischemia (6), and that despite the theory that this decrease is due to a water shift from extra-cellular to intra-cellular space, purely intra-cellular metabolites also show a reduction of diffusion by a similar magnitude without any compartmental shifts (4,7-12). Thus, diffusion-weighted spectroscopy can add insight into the biophysical properties of diffusion in tissue, but it remains to be tested whether or not diffusion of intra-cellular metabolites will provide evidence of neuronal/axonal abnormalities in the absence of changes in either water diffusion or other MR properties in a variety of neurologic disorders beyond ischemia.Since diffusion is known to be anisotropic in white matter, for either water or metabolites (13-15), it can only be characterized properly by measuring the full diffusion tensor, with an unavoidable time penalty. The mean diffusivity and the degree of anisotropy provide independent and unique inferences on the micro-structural integrity of the white matter tracts (16). N-acetyl aspartate (NAA) is located in the intracellular space of neurons and axons, while creatine and phosphocreatine (tCr), and choline (Cho) are located, not only in the neurons and axons, but also in the more presumably isotropic environments within astrocytes, oligodendrocytes, and meningeal cells (17). It may be hypothesized that tCr and Cho might exhibit different degrees of anisotropy as compared to NAA ...

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Diffusion ordered nuclear magnetic resonance spectroscopy: principles and applications

Cited by 1,554 publications

References 97 publications

NMR study of the influence of pH on phenol sorption in cationic CTAB micellar solutions

NMR study of the influence of pH on phenol sorption in cationic CTAB micellar solutions

Diffusion-ordered nuclear magnetic resonance spectroscopy for analysis of DNA secondary structural elements

Diffusion tensor spectroscopy (DTS) of human brain

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