Epidemiologic analysis of the clinical features of Japanese patients with polymyositis and dermatomyositis

Objectives: This study aimed to investigate the clinical characteristics of polymyositis/dermatomyositis (PM/DM) in Japan by analyzing data from the nationwide registration system.

Methods: The data of the registration system in 2009 were analyzed to investigate patient numbers, sex, clinical symptoms, therapies, complications, and prognosis of PM/DM.

Results: The total number of PM/DM cases was approximately 17,000, and the female/male sex ratio was 2.7:1. Almost all patients improved as a result of therapy, but many suffered from sequelae such as muscle weakness.

Conclusions: The results characterize significant aspects of Japanese PM/DM patients. However, a further prospective survey is required to clarify the true epidemiology and natural history of PM/DM.     

Application of the Human Hepatitis B Virus Core Antigen from Transgenic Tobacco Plants for Serological Diagnosis

Background and objectives: The aim was to produce HBcAg from plants more cheaply than can be done by other currently available means, and to apply such antigen to immunoassay procedures for pretransfusion testing of donor blood. Materials and methods: Transgenic Nicotiana tabacum cv. SR-1 plants expressing the human hepatitis B virus (HBV) core antigen (HBcAg) gene were generated by Agrobacterium-mediated transformation. The recombinant product, called tHBcAg, can assemble itself into a spherical particle with a diameter of 25 to 30 nm, and can maintain two antigenic determinants of HBcAg, namely HBc/α and HBc/β. Partly purified tHBcAg was used in the hemagglutinationinhibition (HI) test, as routinely used by the Japanese Blood Center, to test a panel of 524 blood units taken from HBV-positive donors. Results: In the HI test, tHBcAg showed serologic properties comparable to that from Escherichia coli, the standard antigen used in the Japanese Blood Center. Conclusions: Transgenic plants can produce reagents for serologic testing and perhaps even such medical materials as oral vaccines.     

Identification of a fibrin-independent platelet contractile mechanism regulating primary hemostasis and thrombus growth

A fundamental property of platelets is their ability to transmit cytoskeletal contractile forces to extracellular matrices. While the importance of the platelet contractile mechanism in regulating fibrin clot retraction is well established, its role in regulating the primary hemostatic response, independent of blood coagulation, remains ill defined. Real-time analysis of platelet adhesion and aggregation on a collagen substrate revealed a prominent contractile phase during thrombus development, associated with a 30% to 40% reduction in thrombus volume. Thrombus contraction developed independent of thrombin and fibrin and resulted in the tight packing of aggregated platelets. Inhibition of the platelet contractile mechanism, with the myosin IIA inhibitor blebbistatin or through Rho kinase antagonism, markedly inhibited thrombus contraction, preventing the tight packing of aggregated platelets and undermining thrombus stability in vitro. Using a new intravital hemostatic model, we demonstrate that the platelet contractile mechanism is critical for maintaining the integrity of the primary hemostatic plug, independent of thrombin and fibrin generation. These studies demonstrate an important role for the platelet contractile mechanism in regulating primary hemostasis and thrombus growth. Furthermore, they provide new insight into the underlying bleeding diathesis associated with platelet contractility defects.