Statistical analysis.
Data are presented as median with interquartile ranges or mean with SEM.
The non-parametric Mann-Whitney test was used to compare unpaired values
(GraphPad Prism®). Values of p<0.05 were
considered significant. The level of significance is indicated with
asterisks: *, p<0.05; **, p<0.01; ***,
p<0.001; ****, p<0.0001 and n.s., non-significant.