laboratory andanimal investigations Activation ofPlatelets inBronchial Asthma

Study objectives: Toinvestigate whetherplatelets are activated inasthmatics withincreased release ofpreformed mediators andtoinvestigate theinfluence oforaladministration of theophylline on them. Design: Comparison oftheintracellular free calcium concentration ([Ca2+]j) inplatelets as an indicator ofplatelet activation, CD62Pexpression on platelets, andthechemokine regulated uponactivation innormal T cells expressed andpresumably secreted (RANTES) level in platelet-rich buffer supernatants between asthmatics andnormalsubjects. Setting: Therespiratory outpatient clinics, Hiroshima University, Japan. Participants: Twenty-five normalvolunteers, 19asthmatics taking no oraldrugs associated with asthma treatment(group A), and18asthmatics taking oraltheophylline (group B). Measurements andresults: While theresting [Ca2"1"]^ inplatelets were similar amongthethree groups, the[Ca2+]iS ingroup A were significantly higher thanthose innormalsubjects (p<0.05) andgroupB (p<0.01) after thrombin or 9,ll-epithia-ll, 12-methano-thromboxane