Released and non-precipitated amounts of Fe, Cr, Mn, and Ni in solution from (a) Type 316L and (b) Type 303 exposed to five different solutions (pH 7.4) after 24 h of exposure at 37°C. The asterisks indicate significant differences between different solutions of the indicated metals: *p < 0.05, **p < 0.01, ***p < 0.001.