Probing and gauging of D-Penicillamine xenobiotics in hepatic Wilson disease patients.

D-penicillamine (PA) is the primary chelator of choice to treat Wilson disease (WD). There are limitations in obtaining comprehensive data on PA metabolites in biological specimens by conventional approaches. Hence, the aim of the present was to identify the major hepatic PA metabolites and draw clear conclusions of the drug's xenobiotic in WD.

Identification of primary metabolites in fungal species of Trichophyton mentagrophyte and Trichophyton rubrum by NMR spectroscopy.

Background: Superficial mycoses are fungal infections limited to the outermost layers of the skin and its appendages. The chief causative agents of these mycoses are dermatophytes and yeasts. The diagnosis of dermatophytosis can be made by direct mycological examination with potassium hydroxide (10%-30%) of biological material obtained from patients with suspected mycosis, providing results more rapid than fungal cultures, which may take days or weeks.

Slice selective absorption-mode J-resolved NMR spectroscopy.

Limited chemical shift dispersion and broad multiplet patterns limit resolution in H NMR spectra. J-Resolved spectroscopy overcomes this problem to a great extent. However, the phase-twist line shape in J-Resolved spectroscopy allows only the magnitude mode of the experiment to be practical, which degrades resolution.

Accelerated C detection by concentrating the NMR sample in a biphasic solvent system.

CDCl is the most frequently used solvent for the NMR investigation of organic compounds. Busy chemistry labs need to investigate hundreds of compounds daily. While H NMR investigation takes a couple of minutes, recording C NMR spectra necessitates hours of signal averaging due to the low abundance and low sensitivity of C nuclei.

H NMR-Based Metabolic Signatures in the Liver and Brain in a Rat Model of Hepatic Encephalopathy.

Hepatic encephalopathy (HE) is a debilitating neuropsychiatric complication associated with acute and chronic liver failure. It is characterized by diverse symptoms with variable severity that includes cognitive and motor deficits. The aim of the study is to assess metabolic alterations in the brain and liver using nuclear magnetic resonance (NMR) spectroscopy and subsequent multivariate analyses to characterize metabolic signatures associated with HE.

Pure shift HMQC: Resolution and sensitivity enhancement by bilinear rotation decoupling in the indirect and direct dimensions.

The heteronuclear multiple-quantum coherence in the indirect dimension of the two-dimensional HMQC experiment evolves under the passive H-H J-couplings leading to multiplet structures in the F dimension. Besides, H-H J-multiplets appear in the direct dimension as well. Thus, multiplets along both dimensions lower the resolution and sensitivity of this technique, when high resolution is required along both dimensions.

DQF J-RES NMR: Suppressing the singlet signals for improving the J-RES spectra from complex mixtures.

Two-dimensional J-RESolved spectroscopy (J-RES) finds routine use in metabolomics for reducing signal overlap as it separates chemical shift and multiplet information along two frequency axes. However, only magnitude mode of the experiment is practical which prevents exploitation of its full resolving power. Tailing from high-intensity metabolite peaks often obscure nearby low-intensity metabolite peaks which leads to ambiguity in assignment of metabolites.

Identification of metabolites in coriander seeds (Coriandrum Sativum L.) aided by ultrahigh resolution total correlation NMR spectroscopy.

NMR is a fast method for obtaining a holistic snapshot of the metabolome and also offers quantitative information without separating the compounds present in a complex mixture. Identification of the metabolites present in a plant extract sample is a crucial step for all plant metabolomics studies. In the present work, we used various two dimensional (2D) NMR methods such as J-resolved NMR, total correlation spectroscopy (TOCSY), and heteronuclear single quantum coherence sensitivity enhanced NMR spectroscopy for the identification of 36 common metabolites present in Coriandrum sativum L.

Perfecting band selective homo-decoupling for decoupling two signals coupled within the same band.

Recently, pure shift NMR methods have delivered ultrahigh resolution broadband proton NMR spectra that display singlet peak per chemical site. BASH/HOBS (band selective homo-decoupling/homonuclear band selective) decoupling is the only method that provides singlet only spectrum for a selected signal or a group of signals with a sensitivity higher than regular proton NMR, and an order of magnitude higher than broadband pure shift techniques. It is this aspect that makes this technique important.

Insight into old and new pure shift nuclear magnetic resonance methods for enantiodiscrimination.

Enantiodiscrimination and their quantification using nuclear magnetic resonance (NMR) spectroscopy has always been a subject of great interest. Proton is the nucleus of choice for enantiodiscrimination due to its high sensitivity and ubiquitous presence in nature. Despite its advantages, enantiodiscrimination suffers from extensive signal splitting by the proton-proton scalar couplings, which give complex multiplets that spread over a frequency range of some tens of hertz.

Curcumin stably interacts with DNA hairpin through minor groove binding and demonstrates enhanced cytotoxicity in combination with FdU nucleotides.

We report, based on biophysical studies and molecular mechanical calculations that curcumin binds DNA hairpin in the minor groove adjacent to the loop region forming a stable complex. UV-Vis and fluorescence spectroscopy indicated interaction of curcumin with DNA hairpin. In this novel binding motif, two ɣ H of curcumin heptadiene chain are closely positioned to the A-H8 and A-H8, while G-H8 is located in the close proximity of curcumin α H.

Parallel acquisition of slice-selective H-H soft COSY spectra.

A method is demonstrated for parallel acquisition of several slice selective soft COSY proton spectra. Application of a slice selective mixing pulse in a selective correlation experiment allows slice selective coherence transfer between different coupled spin pairs. During such slice selective coherence transfer, the spin states of the passive spins are undisturbed.

Analyses of Complex Mixtures by F Homo-Decoupled Diagonal Suppressed Total Correlation Spectroscopy.

A diagonal suppressed F decoupled total correlation spectroscopy(TOCSY) experiment is developed for analyses of complex mixtures. In 2D homonuclear correlation, assignment of the cross peaks is crucial for structure elucidation. However, when cross peaks are close to the diagonal peaks in overcrowded spectral regions, their assignment becomes tedious.

Altered metabolites of the rat hippocampus after mild and moderate traumatic brain injury - a combined in vivo and in vitro H-MRS study.

Traumatic brain injury (TBI) has been shown to affect hippocampus-associated learning, memory and higher cognitive functions, which may be a consequence of metabolic alterations. Hippocampus-associated disorders may vary depending on the severity of injury [mild TBI (miTBI) and moderate TBI (moTBI)] and time since injury. The underlying hippocampal metabolic irregularities may provide an insight into the pathological process following TBI.

Real time band selective F -decoupled proton NMR for the demixing of overlay spectra of chiral molecules.

The small chemical shift dispersion and complex multiplicity pattern in proton NMR limit quantifications, for instance the determination of enantiomeric excess (ee) for an enantiomeric mixture. Herein, we present a simple proton-proton correlation experiment with band selective homonuclear (BASH) decoupling in both F and F dimensions, for the removal of scalar and residual dipolar couplings to provide collapsed singlet for each chemical site. The method has been demonstrated to separate the severely overlapped spectra of enantiomers using both chiral isotropic and anisotropic phases as well as a small biomolecule, particularly for the diastereotopic protons and also for the determination of ee.

Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience.

"Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension.

Real-time band-selective homonuclear proton decoupling for improving sensitivity and resolution in phase-sensitive J-resolved spectroscopy.

Real-time band-selective homonuclear (1) H decoupling during data acquisition of z-filtered J-resolved spectroscopy produces (1) H-decoupled (1) H NMR spectra and leads to sensitivity enhancement and improved resolution, and thus aids the measurement of J couplings and residual dipolar couplings in crowded regions of (1) H NMR spectrum. High quality spectra from peptides, organic molecules, and also from enantiomers dissolved in weakly aligned chiral media are reported.

Diagonal free homonuclear correlation using heteronuclei at natural abundance.

Homonuclear correlated spectroscopy such as COSY and TOCSY provides crucial structural information. In all homonuclear correlation, the most intense peaks are represented by the diagonal. As a result, the useful cross peaks close to the diagonal get obscured by the huge tails of diagonal peaks.

Elimination of Zero-Quantum artifacts and sensitivity enhancement in perfect echo based 2D NOESY.

Zero-Quantum artifacts seriously degrade the performance of 2D NOESY. Homonuclear J-evolution during t(1) period generates Zero-Quantum and other higher quantum coherences which represent the magnetization loss and the artifacts created. We demonstrate that creation of such artifacts itself can be prevented for shorter t1 period by a perfect echo based decoupling technique during t1 period in a single scan.

"Perfect echo" INEPT: more efficient heteronuclear polarization transfer by refocusing homonuclear J-coupling interaction.

A "perfect echo" based INEPT experiment that demonstrates more efficient heteronuclear polarization transfer over conventional INEPT has been developed. This scheme refocuses the effect of homonuclear (1)H-(1)H J-evolution and simultaneously allows heteronuclear (13)C-(1)H J-evolution to continue during INEPT. This improves one bond heteronuclear polarization transfer efficiency at longer INEPT transfer delays and also enhances the sensitivity of long range INEPT.

Super-resolved parallel MRI by spatiotemporal encoding.

Recent studies described an "ultrafast" scanning method based on spatiotemporal (SPEN) principles. SPEN demonstrates numerous potential advantages over EPI-based alternatives, at no additional expense in experimental complexity. An important aspect that SPEN still needs to achieve for providing a competitive ultrafast MRI acquisition alternative, entails exploiting parallel imaging algorithms without compromising its proven capabilities.

"Perfect echo" HMQC: sensitivity and resolution enhancement by broadband homonuclear decoupling.

Homonuclear (1)H-(1)H J-modulation leads to J-multiplets in F1 dimension of 2D (1)H-(13)C HMQC spectra. This hampers unambiguous signal assignment for overcrowded (13)C spectra. Broadband homonuclear decoupling has been achieved in the indirect t1 evolution period by incorporating blocks of perfect echo.

Quenching homonuclear couplings in magnetic resonance by trains of non-refocusing pulses.

Trains of 2π or 4π pulses fail to refocus offsets but can suppress the effects of bilinear interactions such as homonuclear scalar couplings.

Transverse relaxation of scalar-coupled protons.

In a preliminary communication (B. Baishya, T. F.