Article Text

Download PDFPDF
Authors' response

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Funding This work was supported by FAPESP, grant number 98/11205, 06/53772-7 and CNPq 03763/2010-8.

  • Competing interests None.

  • Ethics approval The Ethics Committee at the Instituto de Ciências Biomédicas Universidade de São Paulo.

  • Provenance and peer review Commissioned; internally peer reviewed.