High resolution 1H n.m.r. studies of vertebrate blood and plasma

Abstract

Spin echo Fourier transform proton n.m.r. spectra of whole blood contain resonances from both erythrocytes and plasma. A large number of well-resolved signals from mobile protons of low-molecular-weight metabolites in plasma and serum have been identified. Spectra from the plasmas of eight animal species and commercial, quality control sera are compared. CaEDTA2- and MgEDTA2- resonances can be used for the simultaneous determination of EDTA-chelatable calcium and magnesium concentrations in intact plasma and other biological fluids. Cholesterol is too immobile to contribute to the spectra of intact plasma, but is readily estimated by n.m.r. in both its free and esterified forms after extraction into methanol.

1H NMR studies of human blood plasma Assignment of resonances for lipoproteins

“…This resonance is broader for LDL than for HDL and disappears from the (t = 60 ms) Hahn spin-echo spectrum, and enables HDL to be distinguished from LDL. The CH3 resonances from HDL and LDL (1,2) overlap, but only the CH2 resonance LDL (5) appears in the spin-echo spectrum. It is not possible to say whether the NMeJ-protons and CH3 protons seen in spectra of HDL belong to the same molecules (phosphatidylcholines).…”

“…It appeared from our Hahn spin-echo NMR studies that these resonances [1,2] contained several overlapping components. We report here the assignment of specific ~H NMR resonances in 500 MHz spectra of human blood plasma to chylomicrons, VLDL, LDL and HDL, using singlepulse and especially spin-echo NMR spectroscopy.…”

“…Human plasma samples from healthy volunteers were collected as described [1,2]. 'Fresh' samples were studied by NMR within 5 min of separating from whole blood.…”

“…1H NMR spectra of blood plasma consist of relatively sharp resonances from low-Mr metabolites superimposed on a broad protein envelope arising mainly from albumin and immunoglobulins [1][2][3]. Strong signals in the 0.8-1.3 ppm region have been assigned to CH3 and CHz groups of 'mobile' fatty acid components of chylomicrons and lipoproteins.…”

NMR-based metabonomic approaches for evaluating physiological influences on biofluid composition

“…For instance, the large reduction in urinary excretion of the tricarboxylic acid (TCA) cycle intermediates succinate, citrate and 2-oxoglutarate, observed as a result of metabolic acidosis induced by a non-toxic renal carbonic anhydrase inhibitor, such as acetazolamide, could possibly be mistaken for a toxic response. 16 The concept of metabonomics has been distilled from a large number of studies involving the application of NMR spectroscopy to the study of the metabolic composition of a wide range of biofluids and tissues 8,12,15,[22][23][24] and the approach as a whole has been reviewed recently. 25,26 1 H NMR spectroscopy has been successfully used to identify a number of novel metabolic markers of organ-specific toxicity in the rat.…”