3D CONFOCAL IMAGERY OF THE HUMAN BRAIN CHALCEDONY (SiO2) FROM ELDERLY PATIENTS

PRADO FIGUEROA M, J S¨¢NCHEZ LIH¨®N.

ACTA MICROSCOPICA

CIASEM

Año: 2009 vol. 18 p. 513 - 514

0798-4545

Silicon (Si) is an essential nutrient of fundamental importance to human biology. Aluminum and silicon accumulations have been detected in neurofibrillary tangle-bearing neurons and in normal elderly brain by a combination of scanning electron microscopy and X-ray spectrometry (EDS-SEM). These inorganic elements are related to pathological changes in the cerebral cortex. The presence of chalcedony (microcrystalline silica) was also found in the human brain from elderly people, by using a standard optical petrographic microscope (Prado Figueroa et al., 2008). This paper documents the visualization of chalcedony by using a Leica TCS ¨C SP2 Laser Scanning Confocal Microscope (LSCM). Sections of human brain were collected after autopsy from elderly patients (mean, 81 years old) from INEN (Lima, Per¨²). The autofluorescent character of chalcedony allowed us to obtain three-dimensional images of the crystals, by using a Leica software. The mature prismatic chalcedony was observed in the cerebral cortex and cerebellum. Chalcedony are rhombohedral crystals of about 30 ¦Ìm in size, distributed in patches or aggregates. A less mature chalcedony (silica polymorph) of about 1 or 2 ¦Ìm in size, was also detected near the crystals. This is the first time that a biogenically-produced crystalline mineral phase (i.e., chalcedony) has been observed as 3D images in the human brain from elderly patients by using a LSCM.