Summary. Background: Human platelets contain matrix metalloproteinases (MMPs) that are secreted during platelet activation. Platelet MMPs have been implicated in the regulation of cellular activation and aggregation. Although the proaggregatory effect of MMP-2 has been demonstrated, the functional mechanism is not clearly understood. Objectives: This work was carried out in order to elucidate the biochemical mechanism of MMP-2-associated platelet activation and aggregation. Methods: MMP-2 binding to the platelet surface was analyzed by flow cytometry. The cell surface target of MMP-2 was identified in thrombin receptoractivating peptide-stimulated platelets by immunoprecipitation, Western blotting and fluorescence microscopy. A recombinant hemopexin-like domain was used to characterize the nature of MMP-2 binding to the platelet surface. The functional significance of MMP-2 in platelet activation was investigated by quantitative measurements of the activation markers Pselectin (CD62P) and active a IIb b 3 . The role of MMP-2 in platelet aggregation was analyzed with an aggregometer. Results: ProMMP-2 binds to integrin a IIb b 3 in stimulated platelets in which proMMP-2 is converted into MMP-2. Fibrinogen was able to replace the a IIb b 3 -bound MMP-2. The molecular interaction of MMP-2 and integrin a IIb b 3 was abrogated by the recombinant human hemopexin-like domain of MMP-2, leading to reduced cell surface expression of activation markers CD62P and active a IIb b 3 , and resulting in suppressed platelet aggregation. Conclusion: This work clearly demonstrates that platelet activation and aggregation is regulated by MMP-2 that specifically interacts with integrin a IIb b 3 . The C-terminal hemopexin-like domain of MMP-2 is an essential element for binding to a IIb b 3 .

The objectives of this study were to survey elementary school students regarding the environmental conditions of their elementary schools and to assess the relationship between air pollution and allergic disease using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Therefore, this study was designed as a cross-sectional study. In this study, seven elementary schools were selected and they were classified into three categories. The selection included one school with no traffic-related or other pollutants, three with traffic-related pollutants, and three with traffic-related and other pollutants from industrial and filling station sources. The ISAAC questionnaire survey was given to all of the students except to those in the 1st grade who were presumed to be less likely to be exposed to the school environment than the remainder of the students attending those seven schools. The assessment of allergic disease was conducted on a total of 4,545 students. Three school zones with critical exposure were selected within each school and they were evaluated based on the levels of black carbon (BC), PM10, SO2, NO2, and O3. There was a significant increase in the risks based on the odds ratios of treatment experiences (within 1 year) for allergy-related diseases such as asthma and allergic rhinitis (a) in the school group with traffic-related pollutants and the school group with complex pollutants were 2.12 (1.41-3.19) and 1.59 (1.06-2.37), respectively, in comparison to the school groups with no exposure to pollutants. This was determined based on the odds ratio of symptoms and treatment experiences for allergy-related diseases by group based on the home town zone as a reference. Also, in the case of atopic dermatitis, the odds ratio of treatment experiences (within 1 year) was 1.42 (1.02-1.97), which indicated elevated risks compared to the students in the S1 school. A regression analysis was used to assess the relationship between the substances and the symptomatic experiences within the last year. There were significant increases in the odds ratio of the symptoms associated with allergic rhinitis and the BC and SO2 in the complex pollution areas. The results of the assessment of the relationship between atopic dermatitis-associated symptoms and O3 showed that the odds ratio increased with statistical significance.