Functions Of NMR Spectroscopy
Scientists Felix Bloch and Edward Purcell, each 1952 Nobel Prize Laureats, discovered the magnetic resonance phenomenon in 1946. Over the past 50 years, nuclear magnetic resonance spectroscopy has been used to analyze the microscopic physical and chemical structures of molecules. NMR has become the finest technique for looking closely at the composition of organic compounds. Of all the spectroscopic methods, it is the only one for which a complete analysis and understanding of the total spectrum is typically expected. Bigger amounts of samples are needed than for mass spectroscopy, but NMR is non-caustic, and with today’s current instruments, good data may be obtained from samples weighing less than a milligram.
One way that NMR spectroscopy is used in health care is in monitoring renal transplant function. With the utilization of high field H NMR spectroscopy, patient’s can be assessed regarding the rapid multicomponent analysis of low molecular weight compounds in urine so that patterns of metabolic changes that are associated with early renal allograft dysfunction can be investigated. NMR-generated metabolite data can be correlated with clinical observations, graft biopsy pathology, and data from conventional laboratory techniques for assessing renal function. The NMR spectra of urine from patients with immediate functioning grafts were the same with respect to their patterns of amino acids, organic acids and organic amines, but the patients with delayed or non-functioning grafts showed significantly different metabolite excretion patterns.
In studies on individual patients there were increased urinary levels of trimethylamine-N-oxide (TMAO), dimethylamine (DMA), lactate, acetate, succinate, glycine and alanine during episodes of graft dysfunction. But, only the urinary concentration of TMAO was significantly higher (P < 0.025) in the urine collected from patients during episodes of graft dysfunction (410 102 M TMAO/mm creatinine) than in patients with good graft function (91 18 M TMAO/mm creatinine) or healthy control subjects (100 50 M TMAO/mm creatinine). These findings suggest that graft dysfunction is associated with damage to the renal medulla which causes the release of TMAO into the urine from the damaged renal medullary cells. This shows a possible urinary marker for post-transplant graft dysfunction. Research reveals that NMR spectroscopy of biofluids, when used together with conventional laboratory techniques, is a valuable aid to renal transplant monitoring.