Water suppression with B0 field gradient homospoil pulses in high‐resolution NMR spectroscopy

The combination of a frequency nonselective excitation suppression method (1331 sequence) with selective excitation followed by gradient‐induced dephasing of water transverse magnetization yielded suppression ratios of greater than 10,000:1. The need for gradient preemphasis and correction of Bo field shifts is discussed. The suppression efficiency of this method compared favorably to results obtained using the CPMG spin‐ echo technique to observe metabolite resonances in a urine sample. © 1989 Academic Press, Inc

Invivo Volume-Selective Metabolite Editing Via Correlated Z-Order

Volume‐selected H NMR spectroscopy was combined with spectral editing to selectively detect brain metabolites. The SPACE localization sequence was used to create a voxel of z‐magnetization which could then be edited for any scalar coupled metabolite by the use of selective excitation in the ECZOTIC sequence to generate longitudinal spin order. The sequence returns an edited signal with no intrinsic loss of magnetization. The method was applied to observe approximately 10 m M ethanol and 17 mM lactate in the brain of a dog. © 1990 Academic Press, Inc

In vivo localized 1H NMR spectroscopy at 11.7 Tesla

The SPACE volume-selection technique has been used to acquire high-resolution H spectra from the brain of neonate mice at 11.7 T (500 MHz). Spectra were acquired from voxels smaller than 20 μl. The spectra display elevated intensities of resonances arising from taurine and reduced intensities of those arising from N-acetylaspartate, when compared to those of mature animals, correlating well with in vitro studies. An integrated probe design consisting of separate transmission and reception RF coils and linear gradient coils is described. Comments are made concerning the advantages and disadvantages of performing gradient-encoded localized spectroscopy at this field strength

Application of High-Field Localized In-Vivo H-1 Mrs to Study Biochemical-Changes in the Thiamin Deficient Rat-Brain Under Glucose-Load

In vivo, volume-selected H-1 NMR spectroscopy employing the SPACE technique was used to monitor biochemical changes in the thiamin deficient rat brain in response to glucose loading. The concentrations of brain N-acetylaspartate, glutamate/glutamine/gamma-aminobutyric acid, lactate and glucose differed significantly from those of control animals. The results are consistent with a metabolic block at the reaction catalyzed by the thiamin dependent enzyme alpha-keto glutarate dehydrogenase soon after the onset of neurological symptoms of thiamin deficiency, and a further block at pyruvate dehydrogenase arising late in the course of thiamin deficiency

Bone Response to Fluoride Exposure Is Influenced by Genetics

Genetic factors influence the effects of fluoride (F) on amelogenesis and bone homeostasis but the underlying molecular mechanisms remain undefined. A label-free proteomics approach was employed to identify and evaluate changes in bone protein expression in two mouse strains having different susceptibilities to develop dental fluorosis and to alter bone quality. In vivo bone formation and histomorphometry after F intake were also evaluated and related to the proteome. Resistant 129P3/J and susceptible A/J mice were assigned to three groups given low-F food and water containing 0, 10 or 50 ppmF for 8 weeks. Plasma was evaluated for alkaline phosphatase activity. Femurs, tibiae and lumbar vertebrae were evaluated using micro-CT analysis and mineral apposition rate (MAR) was measured in cortical bone. For quantitative proteomic analysis, bone proteins were extracted and analyzed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), followed by label-free semi-quantitative differential expression analysis. Alterations in several bone proteins were found among the F treatment groups within each mouse strain and between the strains for each F treatment group (ratio ≥1.5 or ≤0.5; p<0.05). Although F treatment had no significant effects on BMD or bone histomorphometry in either strain, MAR was higher in the 50 ppmF 129P3/J mice than in the 50 ppmF A/J mice treated with 50 ppmF showing that F increased bone formation in a strain-specific manner. Also, F exposure was associated with dose-specific and strain-specific alterations in expression of proteins involved in osteogenesis and osteoclastogenesis. In conclusion, our findings confirm a genetic influence in bone response to F exposure and point to several proteins that may act as targets for the differential F responses in this tissue