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

M. PRADO FIGUEROA; J. S¨¢NCHEZ LIH¨®N

Rosario, Santa Fe, Argentina

Congreso; 10th Inter-American Congress of Electron Microscopy 2009 (CIASEM 2009).; 2009

http://www.ciasem2009.com.ar/upload_extended/ea188559__userid-425.pdf

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. Keywords: neurodegeneration, acetylcholine receptor, oxidative stress, quartz, silica.