Jay W. Pettegrew

Sodium-23 NMR analysis of human whole blood, erythrocytes, and plasma. Chemical shift, spin relaxation, and intracellular sodium concentration studies

Sodium-23 NMR analysis was performed on freshly obtained human whole blood, erythrocytes, and plasma. The intracellular and extracellular sodium signals were separated by adding dysprosium: tripolyphosphate to the plasma bathing the erythrocytes. Quantitation of the intracellular sodium content was easily accomplished by sodium NMR and was shown to agree well with the values obtained by flame photometry. T1 and T2 relaxation studies demonstrated that the sodium in human plasma and within human erythrocytes is substantially different in its physical characteristics than sodium in aqueous solution, and that some fraction of the plasma and erythrocyte sodium is relatively immobilized. Sodium NMR would appear therefore to be a useful method for studying sodium biology in inherited and acquired human diseases.

Membrane biophysical studies of lymphocytes and erythrocytes in manic-depressive illness☆

Recent research suggests that manic-depressive illness is associated with a membrane abnormality which is detectable in peripheral tissues. Using fluorescence spectroscopy, the cellular membrane dynamics of intact erythrocytes and lymphocytes from manic-depressive patients and controls were studied in a double blind fashion. A cross-sectional analysis of membrane dynamics was obtained by using fluorescent probes with known affinity for specific regions of erythrocyte membranes. This preliminary study demonstrates alterations in the hydrocarbon region of erythrocyte membranes and the cell surface of lymphocytes in patients with manic-depressive illness. These abnormalities appear to be independent of clinical symptomatology and medication. The membrane abnormality demonstrated by fluorescence spectroscopy may provide clues to the molecular pathophysiology in manic-depressive illness, as well as a method of diagnosis in presymptomatic patients.

P-31 nuclear magnetic resonance analysis of brain: Normoxic and anoxic brain slices

Perchloric acid extracts were prepared from liquid-N2-frozen gerbil and guinea pig brain slices studied under one of three conditions: O2-incubated, N2-incubated or O2-incubated recovery following N2 incubation. Mole percentages of the various phosphatic components contained in the extracts were determined by phosphorus-31 nuclear magnetic resonance spectroscopy. The brain slice extract spectrum revealed a previously unreported group of brain phosphodiesters at −0.73 δ relative to 85% orthophosphoric acid Although the phosphatic profiles from O2-incubated slices fromgerbils and guinea pigs revealed only minor species variations, which differed quantitatively rather than qualitatively, species-specific differences were made readily apparent and amplified by incubating brain slices under oxygen-deficient conditions. Despite these differences which were most prevalent during the recovery phase, the overall metabolic changes described herein in response to N2-incubation were in accord with the results obtained by other analytical techniques. Inorganic orthophosphate (2.63 δ) was increased, while nucleoside (principally, adenosine) triphosphate (α-, −10.92 δ, β-, −21.45 δ, and γ-, −5.80 δ) and phosphocreatine (−3.12 δ) levels were decreased in response to N2 incubation. In addition, inosine monophosphate (3.78 δ) was increased and the levels of a partially characterized acid-labile phosphate (0.85 δ, guinea pig) were decreased upon N2 incubation. Phosphoglyceride metabolism also appeared to be altered by oxygen deprivation (gerbil). These latter findings provide additional information concerning the metabolic responses of cerebral tissue to oxygen deficient conditions.

Phosphorus 31 NMR of neuroblastoma clonal lines. Effect of cell confluency state and dibutyryl cyclic AMP.

Phosphorus nuclear magnetic resonance is used to study changes in the levels of the major phosphate-containing intermediary metabolites concomitant with induced cellular differentiation in the N-18 and C-46 neuroblastoma clonal lines. The study reveals differences between the31P-NMR profiles of the two clonal lines and also striking differences attendant to dibutyryl cAMP-mediated morphological differentiation in the N-18 clone. Phosphorus-31 NMR would appear to provide a new technique with which to study genetic differentiation.

Dynamic membrane studies in individuals at risk for Huntington's disease.

Lymphocyte plasma membrane dynamics were studied by energy-transfer polarization in twenty-three neurologically normal individuals at-risk for Huntingtons disease (HD). The results were compared to 10 normal controls and 10 known HD patients. The normal and HD subjects segregated into two distinct groups. The at-risk group had findings distributed along a continuum with values similar to known HD patients or to normal controls. These findings suggest that further studies of membrane dynamics will contribute to understanding the molecular defect in HD and to the development of a potential molecular marker.