Brazilian Journal of Medical and Biological Research, Volume: 44, Issue: 12, Pages: 1215-1221, Published: DEC 2011 Brazilian Journal of Medical and Biological Research, Vol 44, Iss 12, Pp 1215-1221 (2011) Brazilian Journal of Medical and Biological Research v.44 n.12 2011 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC