Circulating hematopoietic progenitor cells in runners - Bonsignore, M R; Morici, G; Santoro, A; Pagano, M; Cascio, L; Bonanno, A; Abate, P; Mirabella, F; Profita, M; Insalaco, G; Gioia, M; Vignola, A M; Majolino, I; Testa, U; Hogg, J C (J Appl Physiol, 2002)