Megakaryocytes, which are derived from hematopoietic stem cell precursors in bone marrow, form and release platelets; these circulate in the blood for 8 to 10 days before they are removed by hepatic ...

John Yanni received blood and platelet donations during triple-bypass surgery in 2006. He's made a commitment to donating blood platelets about twice a month for the past 19 years, surpassing 400 ...