SummaryPlatelet-derived microparticles (PMPs) are released from platelets through the platelet activation by high shear stress, collagen, or calcium ionophore (A23187). PMPs are observed in patients with acute myocardial infarction, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, heparin-induced thrombocytopenia and other thrombotic disorders, but the importance of circulating PMPs in the pathogenesis of these diseases is still debated. Numbers of PMPs are usually determined by flowcytometry (FCM), but easier and reproducible PMP assay systems are needed. To develop a better ELISA for PMPs, we used antibodies against the platelet antigens anti-GPIb (NNKY5-5), anti-GPIIb/IIIa (NNKY2-11, anti-CD41), anti-GPIX (KMP-9), and anti-CD9 (NNKY1-19). PMPs were detected with all combinations of these antibodies, but the ELISA having the highest and most specific absorbance was obtained with a combination of KMP-9 (capture antibody) and NNKY5-5 (detecting antibody). PMPs in blood samples were measured by ELISA and FCM. ELISA correlated with PMPs quantitated by FCM. By shaking ELISA plates during incubation, nonspecific binding of platelets was eliminated. The level of PMPs was not increased in diabetes mellitus, thrombotic thrombocytopenic purpura, anti-phospholipid syndrome, or sepsis. The concentration of PMP was elevated in hemolytic uremic syndrome. Activated PMPs were absorbed to 0.8 m filter, but circulating PMPs were not absorbed. These results suggest that activated PMPs are likely to adhere to leukocytes or endothelial cells at the activation site and that the circulating form of PMPs are likely to be a residue of activated PMPs. To detect only the activated form of PMPs, a new ELISA needs to be developed, and it will likely use a combination of antibodies that detect platelet activation markers such as P-selectin (CD62P) or activated GPIIb/IIIa.
Guidelines have not recommended routine echocardiography to predict perioperative cardiac events (PCE). We aimed to evaluate the prognostic significance of tissue Doppler echocardiography-derived E/E' for risk stratification before noncardiac surgery. We reviewed 445 consecutive patients with cardiovascular diseases who had undergone tissue Doppler echocardiography before noncardiac surgery. The revised cardiac risk index (RCRI) was assessed from clinical records. After excluding patients who could not have E/E' measurements, 200 patients were further analyzed. PCEs included death, arrhythmia, myocardial infarction, heart failure and deferred surgery. Eleven patients developed PCEs. E/E' was significantly higher in patients with PCE (18.4 ± 5.8 vs. 12.2 ± 4.5, p< 0.0005). Multivariate analysis showed E/E' (odds ratio 1.2, p < 0.007) and RCRI (OR 4.8; 95%, p < 0.006) were independent predictors of PCE. E/E' appeared to be useful in perioperative risk stratification among patients with cardiovascular diseases undergoing noncardiac surgery.
The scarcity of somatomedin/insulin-like growth factor(SM/IGF) has pre-
SummaryPlatelet-derived microparticles (PDMPs) are produced by platelet activation or physical stimulation under various conditions. To evaluate changes in platelet and chemokine function in patients undergoing percutaneous transluminal coronary angioplasty (PTCA), we measured and compared levels of PDMPs and a C-C chemokine, regulated on activation normally T-cell express and secreted (RANTES), by ELISA. Levels of PDMP and RANTES in patients with acute coronary syndrome were significantly higher than those in the control groups (PDMP: 20.1 ± 2.9 vs 80.4 ± 7.3 U/ml, p < 0.001; RANTES: 18.6 ± 3.7 vs 52.1 ± 4.6 ng/ml, p < 0.01), but did not differ between the control groups and patients with stable angina. PDMP levels were higher in patients with acute myocardial infarction (AMI) than in patients with unstable angina (PDMP:115.0 ± 7.1 vs 63.9 ± 6.2 U/ml, p < 0.001). There was no difference in the RANTES levels, however, between patients with AMI and patients with unstable angina. PDMP and RANTES levels were significantly decreased after PTCA (PDMP, p < 0.001; RANTES, p < 0.05), but without differences between the two groups. In addition, the level of PDMP was significantly correlated with that of RANTES or soluble CD40 ligand. These findings suggest that PTCA may prevent the development of AMI-associated complications in which activated platelets and RANTES play roles. Our ELISA method appears to be sufficient for monitoring PDMP and RANTES levels after PTCA in patients with acute coronary syndrome.
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