已有证据证明巨核细胞不断由骨髓产生,而被肺毛细血管床所捕捉,其碎片在肺转变为血小板。这提示在巨核细胞或其碎片绕过肺毛细血管网,或在心脏左侧或大动脉内形成大的血小板凝块,或有慢性血小板增多倾向的一些疾病中,这些大颗粒可随轴血流到达指端,并在指端阻塞和释放血小板衍生生长因子。已知该物质可引起毛细血管通透性增加和结缔组织增生,是引起杵状指的原因。血小板衍生生长因子(PDGF)存在于血小板α-颗粒,并应存在于巨核细胞内。由于大颗粒易被轴血流携带,所以动脉血中循环的巨核细胞或其碎片特别易在指端阻塞。趾端受到的影响较小,因为距离较远,可能这些大颗粒在到达足趾的途中就被分解。它 There is evidence that megakaryocytes are continually produced by the bone marrow, captured by the pulmonary capillary bed, and their fragments are converted to platelets in the lungs. This suggests that these macroparticles may reach with axial flow in some diseases where megakaryocytes or their fragments bypass the pulmonary capillary network or form large platelet clots in the left or aorta of the heart, or have a tendency to have chronic thrombocytosis Finger-tip, and block and release platelet-derived growth factor at the fingertips. It is known that this substance causes capillary permeability and connective tissue hyperplasia, which is the cause of clubbing. Platelet-derived growth factor (PDGF) is present in platelet alpha-particles and should be present in megakaryocytes. Because large particles are easily carried by axial blood flow, the circulating megakaryocytes or their fragments in the arterial blood are particularly prone to clogged at the fingertip. The toe end is less affected because, at longer distances, these large particles may break down on their way to the toe. it