Brazilian Journal of Medical and Biological Research, Volume: 31, Issue: 11, Pages: 1375-1381, Published: NOV 1998 Brazilian Journal of Medical and Biological Research, Vol 31, Iss 11, Pp 1375-1381 (1998) Brazilian Journal of Medical and Biological Research v.31 n.11 1998 Brazilian Journal of Medical and Biological Research Associação Brasileira de Divulgação Científica (ABDC) instacron:ABDC