Alterações da coagulação associadas à leucemia promielocítica aguda

Acute promyelocytic leukemia is frequently accompanied by coagulation abnormalities usually described as laboratorial disseminated intravascular coagulation, which is the main cause of morbidity and early mortality. Aberrant activation of the coagulation cascade and hyperfibrinolysis play an important role in the pathogenesis of bleeding diathesis, but their contribution varies from case to case. Here we review the main laboratorial findings and the recommended clinical management of coagulopathy associated with acute promyelocytic leukemia.A leucemia promielocítica aguda (LPA) é geralmente acompanhada por anormalidades da coagulação usualmente descritas como coagulação intravascular disseminada e que são a principal causa de mortalidade precoce. A ativação anormal da cascata de coagulação e a hiperfibrinólise desempenham importante papel na patogênese da diátese hemorrágica, mas a contribuição de cada fator varia de caso a caso. Apresentamos aqui uma revisão dos principais achados laboratoriais e da recomendação para o manejo clínico da coagulopatia associada a LPA

Detection of Pneumocystis jirovecii by Two Staining Methods and Two Quantitative PCR Assays

Abstract : Background: : Pneumocystis jirovecii is an opportunistic pathogen that causes pneumonia, particularly in immunodeficient hosts. Materials and Methods: : We retrospectively compared the results obtained by two staining methods (toluidine blue and calcofluor white) and two quantitative (q) real time PCR assays for the detection of P. jirovecii in bronchoalveolar lavage (BAL) specimens. For the qPCR assays, we used newly selected probes and primers targeting the Kex-1 gene, which codes for a serine endoprotease, and compared the results to those from the published assay targeting the β-tubulin gene. Results: : A total of 1,843 BAL specimens were analyzed microscopically in parallel, and 74 (4.0%) were found to be positive with both stains, 23 (1.2%) were positive only with the toluidine blue stain, and six (0.3%) only with the calcofluor stain (p = 0.003). Of these, a selection of 186 consecutive BAL fluid samples were tested by qPCR using the respective different primer pairs. 21 of the 186 samples (11.3%) were microscopically positive with both stains as well as qPCR positive after 18-31 cycles (corresponding to 5.24 × 106 copies/ml to 640 copies/ml of native BAL) using the Kex-1 primer pair and between 21-33 cycles using the β-tubulin assay. A good correlation between semi-quantitative microscopy and the number of PCR cycles needed for a positive signal was noted. Of the remaining 165 samples, 153 (82%) were both microscopically and PCR negative (PCR with the two sets of primers); the remaining 12 samples (7%) were Kex-1-based PCR positive (from cycles 33 to 41, corresponding to 160 copies/ml of BAL or less) but microscopically negative. Of these latter samples, ten (6%) were also positive (from cycles 34 to 38) with the primers targeting the β-tubulin gene. Taking microscopy as a reference, the sensitivity of qPCR targeting the Kex-1 gene was 100%, and the specificity was 92.4%. Conclusion: : The sensitive qPCR analysis proved to be a rapid and reliable method to detect P. jirovecii in BA

A Study of Nash Equilibrium in Contribution Games for Peer-to-Peer Networks

We consider a stylized model of content contribution in a peer-to-peer network. The model is appealing because it allows for linear-quadratic payoff functions and for very general interaction patterns among agents. Furthermore, when the model has a unique Nash equilibrium (NE) we find that it is defined by a network centrality measure (Bonacich 1987), with L1 and L2 norms of the Bonacich index vector providing aggregate contribution and social welfare. Furthermore, we find that NE are always (even when they are non-unique) computable by solving a linear complementarity problem. We study the network designer's problem of engineering the most efficient equilibrium outcome, proving that maximizing aggregate contribution can be reconciled with maximizing aggregate welfare. We also provide a partial characterization of optimal NE graphs and suggest different approaches for how a network designer can promote more efficient graph structures.Engineering and Applied Science

The Importance of Network Topology in Local Contribution Games

We consider a model of content contribution in peer-to-peer networks with linear quadratic payoffs and very general interaction patterns. We find that Nash equilibria of this game always exist; moreover, they are computable by solving a linear complementarity problem. The equilibrium is unique when goods are strategic complements or weak substitutes and contributions are proportional to a network centrality measure called the Bonacich index. In the case of public goods, the equilibrium is non-unique and characterized by k-order maximal independent sets. The structure of optimal networks is always star-like when the game exhibits strict or weak complements. Under public good scenarios, while star-like networks remain optimal in the best case, they also yield the worst-performing equilibria. We also discuss a network-based policy for improving the equilibrium performance of networks by the exclusion of a single player.Engineering and Applied Science

Severe Mycoplasma hominis Infections in Two Renal Transplant Patients

Systemic infections due to Mycoplasma hominis are rare and occur mainly in immunocompromised patients. Reported here are the cases of two renal transplant patients with peritonitis who did not respond to empirical antimicrobial treatment. Effective treatment with doxycycline was administered only after definitive identification of Mycoplasma hominis was achieved. For this identification, the new genetic amplification-sequencing method was invaluabl

Quality and Price Effects on Technology Adoption

We study the adoption patterns of two competing technologies as well as the effectiveness and optimality of viral pricing strategies. Our model considers two incompatible technologies of differing quality and a market in which valuations are heterogeneous and subject to externalities. We provide partial characterization results about the structure and robustness of equilibria and give conditions under which a technology purveyor can gains in market share. We show that myopic best-response dynamics are monotonic and convergent, and propose two pricing mechanisms using this insight to help a technology seller tip the market in its favor. In particular, we show that non-discriminatory pricing is less costly and just as effective as a discriminatory policy. Finally, we study endogenous pricing using simulations and now find, in contrast to our analytical results with exogenous prices, that a higher quality technology consistently holds a competitive advantage over the lower quality competitor, irrespective of its market share

REGISTRO DE SÉRIE DE IMAGENS LANDSAT USANDO CORRELAÇÃO E ANÁLISE DE RELAÇÃO ESPACIAL

O acervo histórico de imagens Landsat permite realizar estudos multitemporais usando uma longa série de imagens. Para isto, as imagens devem ser registradas, ou seja, sua geometria deve ser compatibilizada. Esta tarefa é geralmente executada usando pontos de apoio visíveis nas duas imagens para estimar o modelo de transformação. A escolha e detecção visual de pontos homólogos é uma tarefa árdua e trabalhosa. Neste trabalho é descrito um método automático para a identificação de pontos homólogos usando a correlação entre pares de imagens digitais. Como a correlação pode identificar falsos positivos, ou seja, pontos com alta correlação, mas fora da posição correta, este resultado é refinado analisando a relação espacial entre os pontos disponíveis. Nos experimentos foi utilizada uma área com grande diversidade na paisagem, com agricultura intensiva, malha urbana densa e estradas em grande quantidade, além de um rio, permitindo assim se obter pontos de controle com alvos diversificados. Os resultados obtidos mostram que o processo pode ser automatizado, mas que o sucesso do processo depende da qualidade, em termos de contraste, das regiões usadas na correlaçã