31P MAS-NMR of human erythrocytes: independence of cell volume from angular velocity.
31P magic angle spinning NMR (MAS-NMR) spectra were obtained from suspensions of human red blood cells (RBCs) that contained the cell-volume-sensitive probe molecule, dimethyl methylphosphonate (DMMP). A mathematical representation of the spectral-peak shape, including the separation and width-at-half-height in the 31P NMR spectra, as a function of rotor speed, enabled us to explore the extent to which a change in cell volume would be reflected in the spectra if it occurred. We concluded that a fractional volume change in excess of 3% would have been detected by our experiments. Thus, the experiments indicated that the mean cell volume did not change by this amount even at the highest spinning rate of 7 kHz. The mean cell volume and intracellular 31P line-width were independent of the packing density of the cells and of the initial cell volume. The relationship of these conclusions to other non-NMR studies of pressure effects on cells is noted.
Kuchel
P W
PW
School of Molecular and Microbial Biosciences, University of Sydney, NSW, Australia. p.kuchel@mmb.usyd.edu.au
Bubb
W A
WA
Ramadan
S
S
Chapman
B E
BE
Philp
D J
DJ
Coen
M
M
Gready
J E
JE
Harvey
P J
PJ
McLean
A J
AJ
Hook
J
J
D003198:Computer Simulation; D004911:Erythrocyte Volume; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009943:Organophosphorus Compounds; D010761:Phosphorus Radioisotopes; D011312:Pressure; D013696:Temperature
D009943:Organophosphorus Compounds; D010761:Phosphorus Radioisotopes; C031116:dimethyl methylphosphonate