title: Sodium ions in ordered environments in biological systems: analysis of 23Na NMR spectra.
abstract: Experimentsthat selectively excite I = 32 nuclei exhibiting residual quadrupolar splittings are used to acquire 23Na NMR spectra from a range of biologically relevant samples containing sodium in ordered environments. Three complementary approaches to the analysis of such spectra are described: (i) measurement of relaxation rates, (ii) extraction of homogeneous linewidths from two-dimensional Jeener-Broekaert spectra, and (iii) simultaneous fitting of detailed theoretical functions to a series of one-dimensional Jeener-Broekaert spectra. Analysis of relaxation rates provides evidence for compartmentation in bovine nasal cartilage. Each approach is used to demonstrate the presence of anisotropy in transverse relaxation in porcine tendon. For certain samples containing collagen, a good theoretical fit to the spectra was obtained using a model that allows for anisotropic relaxation by including the effects of slow lateral and radial diffusion.
authors.affiliation: Physical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Kemp-Harper
authors.forename: B
authors.initials: B
authors.lastname: Wickstead
authors.forename: S
authors.initials: S
authors.lastname: Wimperis
mesh_terms: D000125:Achilles Tendon / Q000737:chemistry; D000465:Algorithms; D000818:Animals; D002210:Caprylates / Q000737:chemistry; D002356:Cartilage / Q000737:chemistry; D002358:Cartilage, Articular / Q000737:chemistry; D002417:Cattle; D003094:Collagen / Q000737:chemistry; D004058:Diffusion; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009300:Nasal Septum / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D012815:Signal Processing, Computer-Assisted; D012964:Sodium / Q000737:chemistry*; D013552:Swine
chemical_list: D002210:Caprylates; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D003094:Collagen; D012964:Sodium; C031492:octanoic acid