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The effect of sample freezing on proton magic‐angle spinning NMR spectra of biological tissue
Author(s) -
Middleton David A.,
Bradley Daniel P.,
Connor Susan C.,
Mullins Paul G.,
Reid David G.
Publication year - 1998
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910400122
Subject(s) - magic angle spinning , nuclear magnetic resonance , magic angle , spectral line , proton , spinning , chemistry , proton nmr , nmr spectra database , nuclear magnetic resonance spectroscopy , materials science , physics , nuclear physics , polymer chemistry , astronomy
Magic‐angle spinning (MAS) has recently been shown to enhance spectral resolution in NMR examinations of intact biological tissue ex vivo. This work demonstrates that freezing certain tissue samples before examination by 1 H MAS NMR can have a marked effect on their spectra. Spectra of rat kidney after freezing in liquid nitrogen, compared with spectra before freezing, showed a significant increase in signal intensities from alanine (>100%), glutamine (>40%), and glycine (>100%), and a decrease in signals assigned to lipids and other macromolecules. Some resonances‐such as from leucine, valine, isoleucine, and aspartate‐only became visible after freezing the tissue. These observations suggest that low temperature storage of tissue necropsies or biopsies might affect the results of a MAS NMR analysis, possibly resulting in the misinterpretation of metabolite changes to pathogen or disease effects.