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In pressure or volume overload, hypertrophic growth of the myocardium is associated with myofibroblast differentiation, a process in which cardiac fibroblasts express smooth muscle alpha-actin (SMA). The signaling mechanisms that mediate force-induced myofibroblast differentiation and SMA expression are not defined. We examined the role of the(More)
Cortactin regulates the strength of nascent N-cadherin-mediated intercellular adhesions through a tyrosine phosphorylation-dependent mechanism. Currently, the functional significance of cortactin phosphorylation and the kinases responsible for the regulation of adhesion strength are not defined. We show that the nonreceptor tyrosine kinase Fer(More)
The regulation of N-cadherin-mediated intercellular adhesion strength in fibroblasts is poorly characterized; this is due, in part, to a lack of available quantitative models. We used a recombinant N-cadherin chimeric protein and a Rat 2 fibroblast, donor-acceptor cell model, to study the importance of cortical actin filaments and cortactin in the(More)
Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin-mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or(More)
Induction of apoptosis by tensile forces is an important determinant of connective tissue destruction in osteoarthritis and periodontal diseases. We examined the role of molecular components of the unfolded protein response in force-induced apoptosis. Magnetic fields were used to apply tensile force through integrins to cultured fibroblasts bound with(More)
Monitoring of donors with selective IgA deficiency, i.e., with less than 0.5 mg IgA/l, led to the observation that serum IgA levels wer not constant. Small but significant fluctuations in IgA levels were noted (coefficient of variance: 143%) which were greater than the variability inherent in the testing methodology (coefficient of variance: 10%). These(More)
During a 6-year period (1977 to 1982) blood samples from 152 Canadian patients were referred to the national reference laboratory of the Canadian Red Cross Society because the referring hospitals had not been able to determine the cause of the patients' severe nonhemolytic transfusion reactions. Twenty-one patients were found to be IgA deficient, and 12 of(More)
This study was undertaken to document the incidence of immediate, nonhemolytic transfusion reactions and to identify a technique or set of techniques that would best identify the different causes of these reactions. A variety of tests were employed to detect lymphocyte, granulocyte, platelet and anti-IgA antibodies. During this study 26,318 units of blood(More)
Bacterial infection-induced fibrosis affects a wide variety of tissues, including the periodontium, but the mechanisms that dysregulate matrix turnover and mediate fibrosis are not defined. Since collagen turnover by phagocytosis is an important pathway for matrix remodeling, we studied the effect of the bacterial and eukaryotic cell metabolite,(More)