THE GROWTH OF CHALCEDONY IN HUMAN BRAINS FROM ELDERLY PATIENTS

M. PRADO FIGUEROA; J. SÁNCHEZ LIHÓN

San Miguel de Tucumán, Argentina.

Congreso; Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB), XLV Reunión Anual; 2009

Sociedad Argentina de Bioquímica y Biología Molecular (SAIB)

The presence of autofluorescent chalcedony (microcrystalline silica, SiO2) in autopsy-derived human brain tissue from older persons is documented by using a Leica laser scanning confocal microscope (LSCM). Three ion lasers were used: Ar 488; HeNe 543 and HeNe 633. Haematoxylin-eosin (H/E) stained sections from routine neurohistologic preparations were analyzed. These sections have been previously studied by a mineralogical microscope (Prado Figueroa et al., 2008). The autofluorescent character of chalcedony allowed us to obtain three-dimensional images of the crystals. It is possible to visualize the degree of crystallinity (maturation) of chalcedony by using a LSCM. The occurance of mature prismatic quartz (chalcedony) was observed. Chalcedony is approximately 30 micron in size, distributed in patches or aggregates and it belongs to the rhombohedral (trigonal) crystal system. A less mature silica polymorph of about 1 or 2 micron in size, with different degree of crystallinity was also detected near of chalcedony. These autofluorescent crystallites were detected using an argon ion laser with the emission band at 457. Around of the chalcedony, the distribution of crystallites was in spiral. Our images perhaps show the growth of chalcedony in the human brain, grain by grain, in an older person.