Presence Of Extracellular Space Research Articles

Na 4Lu(III)HDOTP as extracellular marker in indirect mapping of intracellular ion levels in heart tissue via microbeam PIXE

The determination of intracellular elemental concentrations in cryo-sections of cardiac tissue is influenced by the presence of extracellular space (ECS). Intracellular elemental concentrations are determined by using a perfusion buffer with Na 4Lu(III)HDOTP as an extracellular marker, thus making it possible to correct for the ECS. Results show that when a regular perfusion buffer is replaced by a buffer containing 5 mM Na 4Lu(III)HDOTP, the contractility of an isolated perfused rat heart reduces but recovers completely within a few minutes. The high sensitivity of particle-induced X-ray emission (PIXE) for Lu and the possibility to add high concentrations of the Lu-buffer without significant physiological effects enables mapping of intracellular elemental concentrations in heart tissue.

Nuclear elemental analyses with a cyclotron on biomedical samples

The Eindhoven scanning proton microprobe enables the determination of the ion content of heart tissue on a sub-cellular scale. It is shown that intra-cellular elemental concentrations can be determined. Measurements are carried out for physiological and patho-physiological rat heart muscle tissue. Important alterations in Na and K concentrations are reported as measured with PIXE, RBS and NFS techniques employing a variable energy cyclotron (3–30 MeV). However, quantitative intra-cellular determinations are hampered by the presence of extra-cellular space (ECS). For this purpose, cobaltic ethylene-diamine-tetra-acetic-acid (Co(III)EDTA) was used as an exogenic ECS marker. The intra-cellular ion concentrations of normoxic tissue after correction for the ECS agree well with the literature values.