Intracellular and intramitochondrial binding of lanthanum in dark degenerating midgut cells of a collembolan (insect).

Lanthanum is known to be a marker of extracellular spaces. Intracellular organelles are always devoid of stain. But dark and damaged cells may be entered by the marker, as studied at the cellular level, using the electron probe X-ray microanalyser. The technique may be used to detect increased permeability at a stage when no fine structural abnormality is discernible.