Principle and Applications of X-ray Microanalysis to Biological Specimens by High Voltage Electron Microscopy

Tetsuji Nagata
2006 Annual Review of Biomedical Sciences  
Nagata T. Principle and Applications of X-Ray Microanalysis to Biological Specimens by High Voltage Electron Microscopy. ARBS Ann Rev Biomed Sci 2004;6:13-78. X-ray microanalysis is a useful technique to qualify and quantify basic elements in biological specimens. This paper reviews the principles, techniques and applications of high voltage electron microscopy (HVEM) at accelerating voltages of 200-400kV to X-ray microanalysis of various elements in biological specimens developed in our
more » ... ory since the late 20 th century. We first quantified the endproducts of histochemical reactions such as Ag in radioautographs, Ce in acid phosphatase reaction and Au in colloidal gold immunostaining using semi-thin sections by HVEM. The P/B ratios of Ag, Ce and Au showed peaks at 350, 400 and 300kV, respectively. Then we analyzed various trace elements such as S, Cl, Ca, Zn which originally existed in cytoplasmic matrix or cell organelles of various cells, and some elements absorbed by experimental administration into cells such as Al, using both conventional chemical fixation and cryo-fixation followed by cryo-sectioning, freeze-drying, or freezesubstitution. As results, some trace elements which originally existed in cytoplasmic matrix or cell organelles of various cells were effectively detected. Zn was demonstrated in Paneth cell granules of mouse intestines and its P/B ratios showed a peak at 300kV. Ca was found in human ligaments and rat mast cells with a maximum of P/B ratios at 350kV. S and Cl were detected in mouse colonic goblet cells with maxima at 300kV. On the other hand, some elements which were absorbed by experimental administration into various organs, such as Al in hepatocytes and uriniferous tubule cells in mice, was detected with a maximum at 300kV.
doi:10.5016/1806-8774.2004v6p13 fatcat:47npez4knjh4ffmgg2f73frbsm