[Volume distribution studies on the platelet populations (author's transl)].

The volume distribution into human platelet populations was investigated in order to determine if thereis a relationship between the cell density and the cell size and if the isolated platelets are homogeneous populations of cells. The platelet populations were isolated from platelet rich plasma or from washed platelets by isopycnic centrifugation on sucrose density gradients. Platelet volume was measured electronically with Coulter F or Coulter Z Bic coupled with Channelyser C 1000. The results show that there exists a direct relationship between platelet density and size, since the volumetric parameters gradually increase from the small platelets of lower density to the larger ones isolated at higher density. Evidence was also obtained that the isolated populations of platelets were heterogeneous and their volume distribution was log-normal. Both the heavy and the light platelet populations were found as a mixture of mainly large or mainly small platelets respectively.