Nguyen, B.D., Meng, X., Donovan, K.J. & Shaka, A.J. SOGGY: solvent-optimized double gradient spectroscopy for water suppression. A comparison with some existing techniques. J. Magn. Reson. 184, 263-274
ABSTRACT Excitation sculpting, a general method to suppress unwanted magnetization while controlling the phase of the retained signal [T.L. Hwang, A.J. Shaka, Water suppression that works. Excitation sculpting using arbitrary waveforms and pulsed field gradients, J. Magn. Reson. Ser. A 112 (1995) 275-279] is a highly effective method of water suppression for both biological and small molecule NMR spectroscopy. In excitation sculpting, a double pulsed field gradient spin echo forms the core of the sequence and pairing a low-power soft 180 degrees (-x) pulse with a high-power 180 degrees (x) all resonances except the water are flipped and retained, while the water peak is attenuated. By replacing the hard 180 degrees pulse in the double echo with a new phase-alternating composite pulse, broadband and adjustable excitation of large bandwidths with simultaneous high water suppression is obtained. This "Solvent-Optimized Gradient-Gradient Spectroscopy" (SOGGY) sequence is a reliable workhorse method for a wide range of practical situations in NMR spectroscopy, optimizing both solute sensitivity and water suppression.
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- "The NMR data collection was automated using a BACS-120 sample changer, ATM (automatic tuning and matching), and Bruker IconNMR™ software. The one-dimensional (1D) proton nuclear magnetic resonance (1H NMR) data was acquired using an excitation sculpting pulse sequence to remove the solvent peak and maintain a flat baseline . The spectra were collected at 300 K with 32 K data points, 128 scans, 16 dummy scans, and a spectral width of 5,483 Hz. "
ABSTRACT: Background Aberrant energy metabolism is a hallmark of cancer. To fulfill the increased energy requirements, tumor cells secrete cytokines/factors inducing muscle and fat degradation in cancer patients, a condition known as cancer cachexia. It accounts for nearly 20% of all cancer-related deaths. However, the mechanistic basis of cancer cachexia and therapies targeting cancer cachexia thus far remain elusive. A ketogenic diet, a high-fat and low-carbohydrate diet that elevates circulating levels of ketone bodies (i.e., acetoacetate, β-hydroxybutyrate, and acetone), serves as an alternative energy source. It has also been proposed that a ketogenic diet leads to systemic metabolic changes. Keeping in view the significant role of metabolic alterations in cancer, we hypothesized that a ketogenic diet may diminish glycolytic flux in tumor cells to alleviate cachexia syndrome and, hence, may provide an efficient therapeutic strategy. Results We observed reduced glycolytic flux in tumor cells upon treatment with ketone bodies. Ketone bodies also diminished glutamine uptake, overall ATP content, and survival in multiple pancreatic cancer cell lines, while inducing apoptosis. A decrease in levels of c-Myc, a metabolic master regulator, and its recruitment on glycolytic gene promoters, was in part responsible for the metabolic phenotype in tumor cells. Ketone body-induced intracellular metabolomic reprogramming in pancreatic cancer cells also leads to a significantly diminished cachexia in cell line models. Our mouse orthotopic xenograft models further confirmed the effect of a ketogenic diet in diminishing tumor growth and cachexia. Conclusions Thus, our studies demonstrate that the cachectic phenotype is in part due to metabolic alterations in tumor cells, which can be reverted by a ketogenic diet, causing reduced tumor growth and inhibition of muscle and body weight loss.09/2014; 2(1):18. DOI:10.1186/2049-3002-2-18
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- "The solvents used as the mobile phase for the chromatographic separation typically include water; however water invariably serves as an impediment during the 1H NMR measurements as it has an intensity that is 106-fold higher than that of a majority of observable metabolite signals in bio-fluids. Sequences such as “WATERGATE,” “excitation sculpting”, “WET”, and “SOGGY” sequences have been employed to reduce solvent signals; however, these solvent suppression techniques have some limitations, and can attenuate analyte signals [30,31,32,33]. Although NOESY-type presaturation does not suffer from these setbacks, it works more effectively when used in the reduction of a single signal . "
ABSTRACT: The complementary use of liquid chromatography (LC) and nuclear magnetic resonance (NMR) has shown high utility in a variety of fields. While the significant benefit of spectral simplification can be achieved for the analysis of complex samples, other limitations remain. For example, 1H LC-NMR suffers from pH dependent chemical shift variations, especially during urine analysis, owing to the high physiological variation of urine pH. Additionally, large solvent signals from the mobile phase in LC can obscure lower intensity signals and severely limit the number of metabolites detected. These limitations, along with sample dilution, hinder the ability to make reliable chemical shift assignments. Recently, stable isotopic labeling has been used to detect quantitatively specific classes of metabolites of interest in biofluids. Here we present a strategy that explores the combined use of two-dimensional hydrophilic interaction chromatography (HILIC) and isotope tagged NMR for the unambiguous identification of carboxyl containing metabolites present in human urine. The ability to separate structurally related compounds chromatographically, in off-line mode, followed by detection using 1H-15N 2D HSQC (two-dimensional heteronuclear single quantum coherence) spectroscopy, resulted in the assignment of low concentration carboxyl-containing metabolites from a library of isotope labeled compounds. The quantitative nature of this strategy is also demonstrated.09/2013; 3(3):575-591. DOI:10.3390/metabo3030575
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- "The most commonly-used water suppression technique is based on saturation of water magnetization by a presaturation pulse (CW) applied during the relaxation delay. Other methods include the WATERGATE scheme (WATER suppression by GrAdient Tailored Excitation)  , ES (Excitation Sculpting)  or, more recently, the SOGGY sequence (Solvent-Optimized Gradient-Gradient spectroscopY) developed by Nguyen et al. . Among all the techniques available in NMR, the analysis of a complex mixture can be simplified by the use of Diffusion-Ordered SpectroscopY (DOSY), in which the introduction of a second dimension allows a diffusion coefficient-based separation of the components  . "
ABSTRACT: The Bipolar Pulse Pair Stimulated Echo NMR pulse sequence was modified to blend the original Excitation Sculpting water signal suppression. The sequence is a powerful tool to generate rapidly, with a good spectrum quality, bidimensional DOSY experiments without solvent signal, thus allowing the analysis of complex mixtures such as plant extracts or biofluids. The sequence has also been successfully implemented for a protein at very-low concentration in interaction with a small ligand, namely the salivary IB5 protein binding the polyphenol epigallocatechine gallate. The artifacts created by this sequence can be observed, checked and removed thanks to NPK and NMRnotebook softwares to give a perfect bidimensional DOSY spectrum.Journal of Magnetic Resonance 10/2008; 196(1):78-83. DOI:10.1016/j.jmr.2008.09.022 · 2.51 Impact Factor