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OBJETIVO: Os marcadores da ativação plaquetária em geral se apresentam elevados na doença arterial coronariana. Desse modo, procuramos identificar a presença e as potenciais associações de diferentes marcadores da ativação plaquetária. MÉTODOS: Estudamos pacientes com angina instável (n=28), pacientes com angina estável (n=36) e pacientes sem doença arterial coronariana (n=30); sexo e idade foram estratificados. Os níveis sangüíneos da molécula de adesão P-selectina, do thromboxane B2 e de serotonina foram medidos por imunoensaios enzimáticos. RESULTADOS: Quando comparamos os grupos, os resultados foram: a P-selectina, o thromboxane B2 e os níveis do serotonina apresentaram-se significativamente mais elevados nos pacientes com angina instável do que nos pacientes com angina estável. CONCLUSÃO: Estes marcadores da ativação plaquetária podem, portanto, identificar formas instáveis de doença arterial coronariana.OBJECTIVE: Markers of platelet activation are elevated in coronary artery disease. We sought to identify the presence and the potential associations of different markers of platelet activation. METHODS: We studied patients with unstable angina (n=28), patients with stable angina (n=36) and patients without coronary artery disease (n=30); sex and age matched. Blood levels of the adhesion molecule P-selectin, Thromboxane B2 and Serotonin were measured by enzyme immunoassays. RESULTS: When we compared the groups the results were: sP-selectin, thromboxane B2 and serotonin levels were significantly higher in patients with unstable angina than in patients with stable angina. CONCLUSION: These markers of platelet activation were able to identify unstable forms of coronary artery disease.

OBJECTIVE: The aim of this study was to identify the participation of the coagulation system in the differential diagnosis of pleural effusions. INTRODUCTION: Imbalance between immunologic and metabolic factors triggers a sequence of events resulting in pleural reactions and accumulation of fluid. The coagulation system, which is fundamental for the maintenance of homeostasis, contributes to the inflammatory process responsible for pleural effusions, and participates in cellular proliferation and migration as well as in the synthesis of inflammatory mediators. METHODS: We evaluated the laboratory profile of coagulation and fibrinolysis in 54 pleural fluids (15 transudates and 39 exudates). RESULTS: The coagulation system acts according to the pathophysiologic mechanisms involved in the development of pleural effusions. In inflammatory effusions (exudates), there is activation of coagulation with increased levels of fragment 1+2 and thrombin-antithrombin complex in addition to reduction of fibrinogen levels due to fibrinolysis and fibrin tissue incorporation. As a consequence, there is activation of the fibrinolytic system with increased levels of fibrin degradation products, including the D-dimer. These changes are not sufficient for differentiation of different subgroups of exudates. In transudates, these events were observed to a lesser degree. CONCLUSION: The coagulation system plays an important role in the development of pleural diseases. Coagulation tests show differences between transudates and exudates but not among exudate subgroups. Understanding the physiopathological mechanisms of pleural disorders may help to define new diagnostic and therapeutic approaches.

Neonatal alloimmune thrombocytopenia is a serious disease, in which the mother produces antibodies against fetal platelet antigens inherited from the father; it is still an underdiagnosed disease. This disease is considered the platelet counterpart of the RhD hemolytic disease of the fetus and newborn, yet in neonatal alloimmune thrombocytopenia the first child is affected with fetal and/or neonatal thrombocytopenia. There is a significant risk of intracranial hemorrhage and severe neurological impairment, with a tendency for earlier and more severe thrombocytopenia in subsequent pregnancies. This article reports a case of neonatal alloimmune thrombocytopenia in the second pregnancy affected and discusses diagnosis, management and the clinical importance of this disease.

O mieloma múltiplo (MM) é o tumor de células plasmocitárias que corresponde a aproximadamente 10% das neoplasias hematológicas. Durante o seu curso clínico, relata-se que 15-30% dos pacientes podem apresentar manifestações hemorrágicas, decorrentes de vários mecanismos fisiopatológicos. Até 1999, era descrito que os pacientes com MM ativo apresentavam incidência de até 10% de tromboembolismo. Porém, com a introdução da talidomida no arsenal terapêutico do MM, foi demonstrado aumento importante da freqüência dos eventos trombóticos venosos e arteriais, especialmente quando associada com outros medicamentos, alcançando a taxa de 35%. Várias medidas tromboprofiláticas farmacológicas foram empregadas visando reduzir essas intercorrências, com resultados variáveis. Até o presente momento ainda não se demonstrou qual o regime antitrombótico mais adequado. Recentemente, uma pesquisa entre membros do Grupo Internacional de Trabalho sobre Mieloma (IMWG) resultou em algumas recomendações terapêuticas. Esta revisão sobre as alterações hemostáticas observadas no mieloma múltiplo procurou abordar os diferentes mecanismos responsáveis pelas hemorragias e tromboses observados no MM, as medidas tromboprofiláticas farmacológicas descritas e seus resultados, e as recentes recomendações do IMWG.Multiple myeloma (MM) is the tumor of plasma cells that accounts for approximately 10% of hematological malignancies. During the clinical course of MM, hemorrhagic symptoms are described in 15- 30% of patients, due to several causes. Until 1999, it was reported that up 10% of patients with active MM had venous thromboembolic events. Nevertheless, since the introduction of thalidomide in the therapeutic arsenal of MM, an important increase of the incidence of arterial and venous thrombotic events were described (up 35%), especially when used in association with other drugs. Several pharmacological thromboprophylactic measures have been introduced in order to decrease these events, but with variable results. The most adequate antithrombotic regimen has not yet been demonstrated. Recently the International Myeloma Working Group (IMWG) developed a survey among its members, resulting in some therapeutic recommendations. This review about hemostatic abnormalities in multiple myeloma had the intention of discussing the different mechanisms responsible for hemorrhagic and thrombotic events in MM, the pharmacological thrombophophylactic measures reported, their results and the recent recommendations of the IMWG.