N or other cyclooxygenase inhibitors were added during platelet preparation. Unless

N or other cyclooxygenase inhibitors were added during platelet preparation. Unless otherwise indicated, 1 mM CaCl2 was added immediately prior to stimulation.plasma was collected and spun at 590 g for 5 minutes. Supernatant was removed from the platelet pellet, and the pellet was fixed in 2.5 glutaraldehyde in 0.1 M phosphate buffer (PB) (pH 7.4). The pellet was washed in PB and then 58-49-1 incubated in 1 osmium tetroxide in PB for 30 minutes. After washing in PB and deionized water, the pellet was incubated in 3 uranyl acetate in deionized water for 30 minutes. After washing with deionized water, the pellet was dehydrated in a graded series of increasing amounts of ethanol (70 , 80 , 90 , 96 , 100 , and 100 , with each step lasting for 10 minutes). After removal of the 100 ethanol, the pellet was incubated with pure Epon for 2 hours at room temperature. Thereafter, the Epon was replaced with fresh Epon, and this was hardened overnight in a 60uC oven. Ultrathin counterstained sections were imaged on a Philips CM100 equipped with a side-mount MegaView III camera (Olympus Soft Imaging Solutions). To determine the dense-granule and a-granule content, total numbers of granules in equivalent-sized fields of view were counted. For each genotype, 10 randomly chosen fields of view were examined. All microscopic images were taken at the same magnification, and the number of cells per field 26001275 of view was equivalent between WT and Myo5a2/2 preparations. The number of dense granules and a-granules is expressed as the mean number 24272870 per platelet slice. This approach allows the number of each granule type to be compared between WT and Myo5a2/2 platelets, although since individual thin sections of platelets are imaged, the number of granules seen is substantially fewer than the total number of granules in individual platelets.Dense granule secretionThe release of ATP from dense granule release was assessed luminometrically, as previously described [15]. Briefly, platelets were incubated with Chrono-Lume luciferase-luciferin reagent before stimulation with the indicated concentration of agonist. ATP secretion was measured as an increase in luminescence.Washed platelets (56107/mL; 32 mL) were incubated fluorescein isothiocyanate (FITC)-labelled anti-P-selectin antibody, phycoerythrin (PE)-labelled JON/A antibody (4 mL of each), and agonist (4 mL; 1:10 dilution) for 10 min under non-stirring conditions. Platelets were then fixed with paraformaldehyde (2 ). Two-colour analysis was conducted by flow cytometry on a FACSCalibur flow cytometer (BD Biosciences), using CellQuest version 3.1f software (BD Biosciences). The platelet population was identified by forward and side scatter profile. To assess the timecourse of a-granule secretion, platelets were stimulated for the indicated time with AYPGKF (300 mM) prior to fixation. FITC-labelled anti-P-selectin was added for the final 30 s of stimulation.Integrin aIIbb3 activation and a-granule secretionElectrophoresis and Western blottingWashed platelets (26108/mL) were lysed in NuPAGE LDS sample buffer which was supplemented with 50 mM dithiothreitol. Samples were separated by electrophoresis on 6 Bis-Tris Teriparatide web polyacrylamide gels. Proteins were then transferred to polyvinylidene difluoride membranes which were blocked with 16 blocking buffer and probed with specific primary and HRPconjugated secondary antibodies. Proteins were detected using ECL reagents.Lysosome secretionWashed platelets (56107/mL; 36 mL) were incubated F.N or other cyclooxygenase inhibitors were added during platelet preparation. Unless otherwise indicated, 1 mM CaCl2 was added immediately prior to stimulation.plasma was collected and spun at 590 g for 5 minutes. Supernatant was removed from the platelet pellet, and the pellet was fixed in 2.5 glutaraldehyde in 0.1 M phosphate buffer (PB) (pH 7.4). The pellet was washed in PB and then incubated in 1 osmium tetroxide in PB for 30 minutes. After washing in PB and deionized water, the pellet was incubated in 3 uranyl acetate in deionized water for 30 minutes. After washing with deionized water, the pellet was dehydrated in a graded series of increasing amounts of ethanol (70 , 80 , 90 , 96 , 100 , and 100 , with each step lasting for 10 minutes). After removal of the 100 ethanol, the pellet was incubated with pure Epon for 2 hours at room temperature. Thereafter, the Epon was replaced with fresh Epon, and this was hardened overnight in a 60uC oven. Ultrathin counterstained sections were imaged on a Philips CM100 equipped with a side-mount MegaView III camera (Olympus Soft Imaging Solutions). To determine the dense-granule and a-granule content, total numbers of granules in equivalent-sized fields of view were counted. For each genotype, 10 randomly chosen fields of view were examined. All microscopic images were taken at the same magnification, and the number of cells per field 26001275 of view was equivalent between WT and Myo5a2/2 preparations. The number of dense granules and a-granules is expressed as the mean number 24272870 per platelet slice. This approach allows the number of each granule type to be compared between WT and Myo5a2/2 platelets, although since individual thin sections of platelets are imaged, the number of granules seen is substantially fewer than the total number of granules in individual platelets.Dense granule secretionThe release of ATP from dense granule release was assessed luminometrically, as previously described [15]. Briefly, platelets were incubated with Chrono-Lume luciferase-luciferin reagent before stimulation with the indicated concentration of agonist. ATP secretion was measured as an increase in luminescence.Washed platelets (56107/mL; 32 mL) were incubated fluorescein isothiocyanate (FITC)-labelled anti-P-selectin antibody, phycoerythrin (PE)-labelled JON/A antibody (4 mL of each), and agonist (4 mL; 1:10 dilution) for 10 min under non-stirring conditions. Platelets were then fixed with paraformaldehyde (2 ). Two-colour analysis was conducted by flow cytometry on a FACSCalibur flow cytometer (BD Biosciences), using CellQuest version 3.1f software (BD Biosciences). The platelet population was identified by forward and side scatter profile. To assess the timecourse of a-granule secretion, platelets were stimulated for the indicated time with AYPGKF (300 mM) prior to fixation. FITC-labelled anti-P-selectin was added for the final 30 s of stimulation.Integrin aIIbb3 activation and a-granule secretionElectrophoresis and Western blottingWashed platelets (26108/mL) were lysed in NuPAGE LDS sample buffer which was supplemented with 50 mM dithiothreitol. Samples were separated by electrophoresis on 6 Bis-Tris polyacrylamide gels. Proteins were then transferred to polyvinylidene difluoride membranes which were blocked with 16 blocking buffer and probed with specific primary and HRPconjugated secondary antibodies. Proteins were detected using ECL reagents.Lysosome secretionWashed platelets (56107/mL; 36 mL) were incubated F.