“…Platelet-derived growth factor concentrations have also been investigated by several other laboratories (Christgau et al, 2006;Cognasse et al, 2006;Doucet et al, 2005;Frechette et al, 2005;Gruber et al, 2002;Kaps et al, 2002;lacoste et al, 2003;Ogino et al, 2006;Schallmoser et al, 2007;Shen et al, 2006;Weibrich et al, 2002;Zimmermann et al, 2003). the results of these analyses are not comparable with our results, because of different preparation methods: All except el Backly et al and Gruber et al (el Backly et al, 2011;Gruber et al, 2002) stored platelets in serum, which also contains growth factors, and/or in platelet additive solution.…”