th  - 1988 - 51st ENC Conference

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180 l17o/Is NMR MICROSCOPY AT CWRU: G. Mateescu* G. Yvars D. Pazara and
N.A. Alldridge b Departments of Chemistry and Biology b Case Western Reserve University
Cleveland, Ohio 44106.
A 9.4 T NMR microscope recently installed on our MSL-400 is opening fascinating new
avenues for interdisciplinary research on our campus. The outstanding feature of the
system is a double resonance probe which allows exact superposition of 170 and IH
images taken from the same slice of the specimen. This is particularly useful in
human, plant, animal, or materials studies where 170 is used either as direct imaging
IH Microimage of
African violet
petiole; individual
cells can be seen.
IH image of 5 mm
tube with H2170
in 20 mm H2160 tube;
note 0-17
induced contrast.
source or as a relaxation agent for characteristic enhancement of proton images. We
will present the first results of combined 170/IH imaging which lead to new insights
into the chemistry of life processes in plants and animals. The resolution limits will
be illustrated with micrographs of human hair, plant, and animal cells and tissues.
Imaging of chemical reactions and tridimensional diffusion will also be demonstrated.
Support from NIH, NSF, and the Ohio Board of Regents is gratefully acknowledged.
181 I APPLICATION OF I-D AND 2-D SODIUM-23 MAGNETIZATION
TRANSFER NMR TO STUDY TRANSMEMBRANE CATION EXCHANGE
Dikoma C. Shungu*and Richard W. Briggs
Department of Radiology,
University of Florida, Gainesville, FL 32610.
While I-D magnetization transfer NMR experiments (i) are use-
ful for determining kinetic rate information in the slow exchange
regime, their use in the study of rapidly relaxing nuclei (e.g.,
Na-23) is a challenging practical problem due to difficulties in
obtaining frequency-selective pulses which are short enough to en-
sure negligible relaxation during their application. This poster
describes how selective inversion of Na-23 resonances with a
spin-lattice relaxation time as short as 12 msec can be effective-
ly achieved. Na-23 inversion transfer experiments performed using
this method are shown to yield reliable rate constants for ion ex-
change across prototype lipid membranes. It is also shown that 2-D
Na-23 NMR can be used to detect transmembrane cation exchange
processes. Possibility of application to in vivo systems is dis-
cussed.
(i) S. Forsen and R.A. Hoffman, J. Chem. Phys., 3_99, 2892 (1963);
40, 1189 (1964); 45, 2049 (1966).
189