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Background: kidney transplant recipients are exposed to multiple pathogenic pathways that may alter short and long-term allograft survival. Metabolomic profiling is useful for detecting potential biomarkers of kidney disease with a predictive capacity. This field is still under development in kidney transplantation and metabolome analysis is faced with analytical challenges. We performed a cross-sectional study including stable kidney transplant patients and aimed to search for relevant associations between baseline plasmatic and urinary metabolites and relevant outcomes over a follow-up period of 3 years. Methods: we performed a cross-sectional study including 72 stable kidney transplant patients with stored plasmatic and urinary samples at the baseline evaluation which were there analyzed by nuclear magnetic resonance in order to quantify and describe metabolites. We performed a 3-year follow-up and searched for relevant associations between renal failure outcomes and baseline metabolites. Between-group comparisons were made after classification by observed estimated glomerular filtration rate slope during the follow-up: positive slope and negative slope. Results: The mean estimated GFR (glomerular filtration rate) was higher at baseline in the patients who exhibited a negative slope during the follow-up (63.4 mL/min/1.73 m2 vs. 55.8 mL/min/1.73 m2, p = 0,019). After log transformation and division by urinary creatinine, urinary dimethylamine (3.63 vs. 3.16, p = 0.027), hippuric acid (7.33 vs. 6.29, p = 0.041), and acetone (1.88 vs. 1, p = 0.023) exhibited higher concentrations in patients with a negative GFR slope when compared to patients with a positive GFR slope. By computing a linear regression, a significant low-strength regression equation between the log 2 transformed plasmatic level of glycine and the estimated glomerular filtration rate was found (F (1,70) = 5.15, p = 0.026), with an R2 of 0.069. Several metabolites were correlated positively with hand grip strength (plasmatic tyrosine with r = 0.336 and p = 0.005 and plasmatic leucine with r = 0.371 and p = 0.002). Other urinary metabolites were found to be correlated negatively with hand grip strength (dimethylamine with r = −0.250 and p = 0.04, citric acid with r = −0.296 and p = 0.014, formic acid with r = −0.349 and p = 0.004, and glycine with r = −0.306 and p = 0.01). Conclusions: some metabolites had different concentrations compared to kidney transplant patients with negative and positive slopes, and significant correlations were found between hand grip strength and urinary and plasmatic metabolites. [ABSTRACT FROM AUTHOR]

Two series of binary halogen-bonded co-crystals involving perfluorinated di- and triiodobenzene (1,2-ditfb, 1,4-ditfb and 1,3,5-titfb) and 1,3-azulenedicarboxaldehyde (azdicho) 1 and 1,3-bis(4-pyridyl)azulene (azbbpy) 2 are reported. The crystal structures of the six new co-crystals show primarily O⋯I or N⋯I interactions, and the subsidiary weak C–H⋯F and π–π interactions of the aromatic units. Because the halogen-bond acceptors contain different heteroatoms and length size, the supramolecular recognition in the co-crystal is quite different. Besides novel structural features formed via halogen-bonding interactions, our results showed that the azulene moiety plays a unique organizing role in the formation and stabilization of supramolecular aggregates through π–π stacking interactions. These non-covalent interactions are investigated by theoretical studies through Hirshfeld surface analysis and DFT calculations followed by topological analysis of the electron density distribution within the QTAIM approach. The co-crystals were also investigated in solution by NMR spectroscopy through 19F-NMR and 1H,15N-HMBC experiments. [ABSTRACT FROM AUTHOR]

A new triazol-3-one resulted unexpectedly from the reduction reaction of a heterocyclic thioketone using sodium borohydride in pyridine containing a small amount of water. The structure of the new compound was characterised using FT-IR, 1D and 2D NMR, and HRMS spectroscopic methods. [ABSTRACT FROM AUTHOR]

One critical step in new drugs development is the investigation of the interactions between drug candidate and target protein. Nuclear Magnetic Resonance Spectroscopy (NMR) is a well-established technique for studding these interactions. Due to its availability and structural similarities to human albumin, bovine serum albumin (BSA) is widely accepted as a model for investigating the binding of small molecules to serum albumin. We report here on the evaluation of binding interactions between BSA and 18 metabolites using saturation transfer difference (STD) NMR experiments. Positive STD signals that indicate metabolite-protein interactions were obtained for leucine, pyruvic acid, valine, threonine, alanine, 4-aminohippuric acid and tryptophan. [ABSTRACT FROM AUTHOR]

Novel indolizines and pyrrolo[1,2-c]pyrimidines bearing a 3-carbonylchromen-2-one moiety on the pyrrole rings were synthesized and spectroscopic properties of some of synthesized compounds were investigated. Synthetic procedures started from 4-substituted pyrimidines, 3-(2-bromoacetyl)-2H-chromen-2-one and electron-deficient alkynes via 3+2 dipolar cycloaddition of cycloimmoniumylides, generated in situ from their corresponding quaternary salts, in the presence of an epoxide playing the role of acid scavenger and reaction solvent. The structures of novel compounds were confirmed by chemical analyses, IR and NMR spectroscopy. Spectroscopic properties of some of the synthesized compounds were investigated. [ABSTRACT FROM AUTHOR]

The saponification value of fats and oils is one of the most common quality indices, reflecting the mean molecular weight of the constituting triacylglycerols. Proton nuclear magnetic resonance (1H-NMR) spectra of fats and oils display specific resonances for the protons from the structural patterns of the triacylglycerols (i.e., the glycerol backbone), methylene (-CH2-) groups, double bonds (-CH=CH-) and the terminal methyl (-CH3) group from the three fatty acyl chains. Consequently, chemometric equations based on the integral values of the 1H-NMR resonances allow for the calculation of the mean molecular weight of triacylglycerol species, leading to the determination of the number of moles of triacylglycerol species per 1 g of fat and eventually to the calculation of the saponification value (SV), expressed as mg KOH/g of fat. The algorithm was verified on a series of binary mixtures of tributyrin (TB) and vegetable oils (i.e., soybean and rapeseed oils) in various ratios, ensuring a wide range of SV. Compared to the conventional technique for SV determination (ISO 3657:2013) based on titration, the obtained 1H-NMR-based saponification values differed by a mean percent deviation of 3%, suggesting the new method is a convenient and rapid alternate approach. Moreover, compared to other reported methods of determining the SV from spectroscopic data, this method is not based on regression equations and, consequently, does not require calibration from a database, as the SV is computed directly and independently from the 1H-NMR spectrum of a given oil/fat sample. [ABSTRACT FROM AUTHOR]