Abstract
The spectroscopic study of pathological calcifications (including kidney stones) is extremely rich and helps to improve the understanding of the physical and chemical processes associated with their formation. While Fourier transform infrared (FTIR) imaging and optical/electron microscopies are routine techniques in hospitals, there has been a dearth of solid-state NMR studies introduced into this area of medical research, probably due to the scarcity of this analytical technique in hospital facilities. This work introduces effective multinuclear and multidimensional solid-state NMR methodologies to study the complex chemical and structural properties characterizing kidney stone composition. As a basis for comparison, three hydrates (, 2 and 3) of calcium oxalate are examined along with nine representative kidney stones. The multinuclear magic angle spinning (MAS) NMR approach adopted investigates the , , and nuclei, with the and MAS NMR data able to be readily deconvoluted into the constituent elements associated with the different oxalates and organics present. For the first time, the full interpretation of highly resolved NMR spectra is presented for the three hydrates, based on the structure and local dynamics. The corresponding MAS NMR data indicates the presence of low-level inorganic phosphate species; however, the complexity of these data make the precise identification of the phases difficult to assign. This work provides physicians, urologists and nephrologists with additional avenues of spectroscopic investigation to interrogate this complex medical dilemma that requires real, multitechnique approaches to generate effective outcomes.
Highlights
Kidney stones (KSs) are a major health problem in industrialized countries
The first contributions related to the study of synthetic calcium oxalates hydrates by 43Ca magic angle spinning (MAS) NMR spectroscopy were proposed by Wong et al (2006) for COT and by Bowers and Kirkpatrick (2011) for the three hydrated phases
This study has demonstrated that the solid-state NMR technique offers a complementary characterization approach for the study of kidney stones and related synthetic model systems
Summary
Kidney stones (KSs) are a major health problem in industrialized countries. For example, the medical costs associated with the treatment of nephrolithiasis in France exceeds EUR 800 million annually. As δiso(1H) values are very sensitive to H-bond networks and to local motional averaging, studies performed on synthetic COM, COD and COT were necessary prior to the detailed analyses of KSs. the following comments have to be made at this stage: (i) first, the 1H DUMBO MAS methodology (νrot = 12 kHz, 700 MHz) is comparable to the very fast MAS/very high magnetic field approach (νrot ∼ 80 kHz, 850 MHz) without any multiple pulses decoupling. In addition to COM and COD resonances, the 1H DUMBO MAS NMR spectrum of KS2 exhibits small new contributions that can be attributed to organic moieties (such as proteins) In this case, a semiquantitative analysis of the KSs appears more difficult to perform. Dipolar-based double quantum (DQ) experiments can be implemented to establish through-space proximities between protons (such as back to back or BABA; Feike et al, 1996)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call