Brazilian Journal of Medical and Biological Research, Volume: 44, Issue: 1, Pages: 38-45, Published: JAN 2011 Brazilian Journal of Medical and Biological Research v.44 n.1 2011 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC Brazilian Journal of Medical and Biological Research, Vol 44, Iss 1, Pp 38-45 (2011)