Null-point titration measurements of free magnesium in stored erythrocytes

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6060897

Bock, J L; Yusuf, Y; Puntillo, E

Free intracellular magnesium concentration (Mg/sub i/) was measured in stored human erythrocytes, using null-point titration with ionophore A23187. For cells stored <10 days in citrated preservation media (CPDA), Mg/sub i/ was 311 +/- 41 ..mu..M (mean +/- SD, N=7), whereas for cells stored 22-48 days it was 483 +/- 64 ..mu..M (N=12). This is in contrast to their earlier measurements by /sup 31/P NMR spectroscopy, which showed a decrease in Mg/sub i/ with storage. However, the NMR measurements are performed with no pretreatment of the cells, while the null-point method requires an initial washing step, which alters pH/sub i/ and may also alter Mg/sub i/. The titration-measured Mg/sub i/ values are still surprisingly low for long-stored cells, considering that depletion of ATP and 2,3-DPG should release bound Mg. Using the titration-measured Mg/sub i/ values along with measurements of total Mg, ATP, and 2,3-DPG, they estimate that an additional buffer contains about 47% of total Mg in cells stored <10 days, and 67% of total Mg in cells stored >21 days. Mg/sub i/ determinations by both /sup 31/P NMR and null-point titration thus indicate that erythrocyte Mg is largely bound to a high-capacity, low-affinity buffer whose relative importance increases during cell storage. Discrepancies between the methods require further investigation.

• Research Organization: New York Medical College, Valhalla
• OSTI ID: 6060897
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism &amp; Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METALS
ATP
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
DISTRIBUTION
ELEMENTS
ERYTHROCYTES
ISOTOPES
LIGHT NUCLEI
MAGNESIUM
MAGNETIC RESONANCE
MATERIALS
MEASURING METHODS
METALS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS 31
PHOSPHORUS ISOTOPES
RESONANCE
SPECTRA
STABLE ISOTOPES
STORAGE
TISSUE DISTRIBUTION
TITRATION