title: Energy dispersive X-ray microanalysis of biological bulk specimens: a review of the method and its application to experimental gerontology and cancer research.
abstract: Biological bulk specimens can be prepared by the freeze-fracture freeze-drying method, which is suitable for quantitative X-ray microanalysis of intracellular components. Although the spatial resolution of this analytic technique does not allow us to analyze smaller cellular compartments than the nucleus and cytoplasm it may deliver useful results for answering questions of experimental biology. Bulk specimens are also suitable for determination of intracellular water and dry mass contents under certain conditions. Applications of the bulk specimen X-ray microanalysis for experimental gerontology revealed an age dependent increase of the intracellular potassium content of the postmitotic cells, a diminution of intracellular water content during aging and delivered indirect proof for the decrease of the passive potassium permeability of the cell membrane in old hepatocytes and giant neurons. The bulk specimen method of X-ray microanalysis has been applied also in cancer research: it proved to be helpful in the determination of intracellular Na+-contents and Na+/K+ ratios in various human and experimental animal tumors as well as in other models of cell proliferation. These data gain a certain weight in light of the recent developments on the regulation of mitogenesis.
mesh_terms: D000375:Aging; D000818:Animals; D001834:Body Water / Q000032:analysis; D002295:Carcinoma, Transitional Cell / Q000648:ultrastructure; D004577:Electron Probe Microanalysis / Q000379:methods; D005614:Freeze Fracturing; D006801:Humans; D007424:Intracellular Fluid / Q000032:analysis; D008099:Liver / Q000254:growth & development / Q000648:ultrastructure*; D009369:Neoplasms / Q000648:ultrastructure*; D051381:Rats; D001749:Urinary Bladder Neoplasms / Q000648:ultrastructure