Neste trabalho mostramos que o método de purificação empregando a coluna ANX Sepharose FF, alternando eluições com CaCl2 (pseudoafinidade) e NaCl, permite obter concentrados do complexo protrombínico e do fator VIII em uma etapa cromatográfica. Testamos as colunas ANX e Q Sepharose FF, monolito QA e membrana Sartobind Q e os tampões citrato, MES e Bis-Tris. Empregando a ANX Sepharose FF e o tampão citrato as proteínas do complexo protrombínico eluiram com CaCl2 25 mM e o FVIII com NaCl 500mM. A recuperação da atividade de FVIII foi de cerca de 60% e o fator de purificação de 220 vezes. Na fração contendo as proteínas do complexo protrombínico foram identificadas por espectrometria de massas a presença de fibrinogênio, proteína C4 do complemento e C4b Binding Protein. A análise das frações mostra que a presença destas proteínas não é devido à variação da concentração de CaCl2, possivelmente se deve à difusão lenta destas através da resina. Mais de 99% das proteínas do plasma não são adsorvidas na coluna e podem ser purificadas em etapas posteriores. / In this study we showed that the purification method employing the anion exchange column ANX Sepharose FF, and alternating CaCl2 (pseudoaffinity) and NaCl elutions, allows us to obtain concentrates of prothrombin complex proteins and factor VIII in a single chromatographic step. We tested the ANX, Q Sepharose FF and QA monolithic column and Sartobind Q membrane and the citrate, MES and Bis-Tris buffers. Using ANX Sepharose FF and the citrate buffer the prothrombin complex proteins eluted with 25 mM CaCl2 and FVIII with 500 mM NaCl. FVIII activity recovery was approximately 60% with a purification factor of 220. In the fraction containing the prothrombin complex proteins presence of fibrinogen, complement C4 and C4bBinding Protein were identified by mass spectrometry. Analysis of the fractions showed that their presence is not due to the variation of concentration of CaCl2, but possibly due to their slow diffusion through the resin. More than 99% of the plasma proteins are not adsorbed in the column and can be purified in following chromatographic steps.

INTRODUÇÃO: A fibrilação atrial (FA) é a arritmia cardíaca mais comum e está associada a uma significativa morbidade e mortalidade. A sua prevalência aumenta marcadamente com a idade. A terapia com anticoagulantes orais tem sido a base de tratamento e prevenção de eventos tromboembólicos em pacientes com FA. Entretanto, a anticoagulação oral em idosos pode ser desafiadora devido à vários fatores, como alterações orgânicas funcionais, risco aumentado de sangramento e eventos isquêmicos, presença de comorbidades, polifarmácia e uma menor aderência ao tratamento. OBJETIVOS: Avaliar a frequência de tromboembolismo e complicações hemorrágicas em pacientes muito idosos (idade >= 85 anos) em uso de varfarina; avaliar tempo na faixa terapêutica (TTR), causas do INR fora da faixa, escores de CHADS2 e CHA2DS2 - VASc, comorbidades associadas e causas de mortalidade. METODOS: análise retrospectiva de pacientes que iniciaram o tratamento com varfarina com uma idade >= 85 anos, entre abril de 1999 e setembro de 2013, controlados em uma clínica de anticoagulação oral. RESULTADOS: foram incluídos 164 pacientes; 51% eram do sexo masculino e a idade média de início e fim do tratamento com varfarina foram de 86,8 e 89,7 anos, respectivamente. A indicação mais comum para o uso de ACo foi a fibrilação atrial (86%). O seguimento médio foi de 34,6 ± 23 meses. O CHADS2 e CHA2DS2 - VASc médio dos pacientes foi 2,78 e 4,7, respectivamente. O tempo na faixa terapêutica (TTR) foi de 58,6%. A polifarmácia esteve presente em 78% dos pacientes. De acordo com as estimativas de Kaplan-Meier, a probabilidade livre de TE e sangramento grave foi de 93,5% e 90,5% em três anos, respectivamente. Quando analisados esses dois desfechos combinados, a probabilidade livre de tromboembolismo e sangramento grave foi de 83,4% em três anos. CONCLUSÃO: nesse estudo, o uso de um antagonista da vitamina k (varfarina) em pacientes com idade >= 85 anos esteve associado a um baixo risco de tromboembolismo e sangramento grave durante o período de seguimento. / INTRODUCTION: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated to a significant morbidity and mortality. Its prevalence strongly increases with aging. Therapy with oral anticoagulants (OAC) has been the basis of treatment and prevention of thromboembolic events in patients with AF. However, oral anticoagulation in the elderly can be challenging due to various factors such as the alteration of organic functions, greater risk of bleeding and ischemic events, presence of comorbidity, polypharmacy and a lower adherence to treatment. OBJECTIVES: Evaluate the frequency of thromboembolism and hemorrhagic complications in very elderly patients (aged >= 85 years) in use of warfarin; evaluate time in therapeutic range (TTR), causes of INR outside the range, scores of CHADS2 and CHA2DS2 - VASc, associated comorbidities and cause of death. METHODS: Retrospective analysis of patients who initiated treatment with warfarin at aged >=85 years, between April of 1999 and September of 2013, controlled in an oral anticoagulation clinic. RESULTS: A total of 164 patients were included in the study; 51% were males and the mean ages at the start and end of the treatment with warfarin were of 86,8 and 89,7 years, respectively. The most common indication for the use of OAC was atrial fibrillation (86%). The mean follow-up was of 34,6 ± 23 months. The mean CHADS2 and CHA2DS2 - VASc of patients was 2,78 and 4,7, respectively. The time in therapeutic range (TTR) was of 58,6%. Polypharmacy was present in 78% of patients. According to the Kaplan-Meier estimates, the survival curve of TE and severe bleeding was of 93,5% and 90,5% in three years, respectively. When these two combined outcomes are analyzed, the survival curve of thromboembolism and severe bleeding was of 83,4% in three years. CONCLUSION: In this study, the use of one vitamin K antagonist (warfarin) in patients aged >= 85 years was associated to a low risk of thromboembolism and severe bleeding during the follow-up period.

La vitamine K permet l’activation biologique de 14 protéines identifiées à ce jour et qualifiées de vitamines K dépendantes (PVKD). Un recyclage très efficient de la vitamine K par l’enzyme VKORC1 permet d’en limiter grandement les besoins nutritionnels. Chez certaines personnes, une subcarence pourrait exister et contribuer au développement de calcifications de la média des parois vasculaires et augmenter ainsi le facteur de risque cardio-vasculaire. Ce type de calcification est retrouvé chez les personnes hémodialysées, présentant un diabète ou tout simplement au cours du vieillissement. Le lien entre cette subcarence et les calcifications vasculaires est difficilement étudiable chez l’Homme du fait d’une évolution lente et d’effets pouvant être masqués par d’autres facteurs environnementaux. Pour pouvoir étudier directement ce phénomène, un modèle murin a été développé et caractérisé. Les rats développés dans de ce modèle ont des besoins fortement augmentés en vitamine K du fait d’un recyclage fortement altéré. Après 12 semaines d’administration déficient en vitamine K, les rats mâles présentaient des calcifications vasculaires médiales importantes de l’aorte, des poumons, des testicules et du cœur. La coagulation est maintenue bien qu’une diminution de l’activité des facteurs de la coagulation vitamine K dépendants soit observée. La matrix-gla-protéine tissulaire ainsi que l’ostéocalcine plasmatique sont retrouvées accumulées sous leur forme inactive. Dans le même temps, la concentration en vitamine K tissulaire est très fortement diminuée. Ces résultats ne sont pas observés chez les rats non mutés subcarencés ni chez les rats mutés non-subcarencé. Ce travail permet pour la première fois de montrer l’existence d’un lien fort entre subcarence en vitamine K et calcifications vasculaires. Ce modèle de subcarence pourrait servir à une meilleure compréhension du rôle des différentes PVKD extra-hépatiques. Il constitue également un modèle de choix pour l’étude des calcifications médiales et de leurs évolutions / Vitamin K allows the biological activation of 14 proteins identified to date and called K-dependent vitamins (PVKD). A highly efficient recycling of vitamin K by the enzyme VKORC1 greatly limits the nutritional requirements. In some people, subcarence may exist and contribute to the development of vascular wall medial calcification and thus increase the cardiovascular risk factor. This type of calcification is found in people with hemodialysis, diabetes or simply during aging. The link between this subcarence and vascular calcification is difficult to study in humans because of a slow evolution and effects that can be masked by other environmental factors. To study this phenomenon directly, a murine model has been developed and characterized. The rats developed in this model have a greatly increased need for vitamin K because of a highly altered recycling. After 12 weeks of vitamin K deficiency, male rats had significant medial vascular calcification of the aorta, lungs, testes and heart. Coagulation is maintained although a decrease in activity of vitamin K-dependent coagulation factors is observed. Matrix-gla-tissue protein as well as plasma osteocalcin are found accumulated in their inactive form. At the same time, the concentration of tissue vitamin K is greatly reduced. These results are not observed in the non-mutated subcarenated rats nor in the non-subcarated mutated rats. This work allows for the first time to show the existence of a strong link between vitamin K subcarence and vascular calcifications. This subcarency model could be used to better understand the role of the different extrahepatic PVKDs. It is also a model of choice for the study of medial calcifications and their evolution

Les anticoagulants antivitamines K (AVKs) sont des molécules qui par inhibition de l'activation des PVKDs, empêchent ou retardent la coagulation sanguine. Aujourd'hui, le traitement par AVKs est la première cause d'accidents iatrogènes médicamenteux chez l'homme. Cependant le bénéfice par rapport au risque étant largement supérieur. Elles sont également utilisées dans le contrôle des populations de rongeurs nuisibles. Les AVKs agissent en inhibant l'enzyme VKORC1. Des phénomènes d'hypersensibilité et de résistance aux AVKs sont apparus et plusieurs mutations spontanées ont été découvertes dans le gène vkorc1. Ces mutations ont alors été associées à la résistance sans que ce lien n'ait jamais été démontré. Le travail, présenté dans ce mémoire, a pour objectif de confirmer ou d'infirmer ces liens de causalité. Cette étude a permis de démontrer la responsabilité des mutations Leu120Gln, Leu128Gln et Tyr139Phe, Ser et Cys dans l'apparition du phénotype résistant aux AVKs de 1ère génération chez le rat sauvage. Les propriétés catalytiques expliquent de plus le coût biologique associé à l'apparition de cette résistance chez certaines lignées de rats sauvages. Ainsi, les mutations en position 139 sont responsables d'un détournement de la catalyse avec production majoritaire d'hydroxyvitamine K directement éliminable par l'organisme. Chez l'homme, 29 mutations sur 30 ont été caractérisées. Alors que ces mutations ont été observées chez des patients résistants aux AVKs, la causalité de ces mutations n'a été démontrée que pour 6 mutations (Ala26Pro, Val41Ser, Val54Leu, His68Tyr, Ile123Asn, Phe139His). Les autres mutations ne seraient pas responsables du phénotype observé

Made available in DSpace on 2016-12-23T13:49:03Z (GMT). No. of bitstreams: 1 Fernanda S Pimentel.pdf: 2000885 bytes, checksum: 1bf180bc2109c67426e7ca0264e6b4ae (MD5) Previous issue date: 2010-07-29 / The bone is a specialized form of connective tissue that provides support for metabolic and biomechanical throughout the body. Thus, the bone is very dynamic, with constantly renewing itself. His integrity therefore depends on the balance between the processes of formation and resorption. The loss of this balance alters both the structure of organic matrix as bone mineralization. Moreover, imbalances in bone remodeling process may result in the development of systemic skeletal diseases such as osteoporosis. The osteoporosis is a chronic progressive disease that affects millions of people around the world. Only in Brazil some 10 million people suffer from osteoporosis. The hormone estrogen deficiency induced by ovariectomy (OVX) rats, demonstrably stimulates increased bone resorption, especially in long bones and spine, mimicking what happens in postmenopausal osteoporosis. In this work we used OVX rats to investigate the interaction of alendronate (a drug widely used to treat osteoporosis) and vitamin K (VK) (recent investigations have pointed anabolic bone tissue of osteoporotic patients) in the metabolism osteomineral. This study revealed that administration of alendronate (ALE) and VK with ALE (ALE+VK) produced significant recovery in bone mineral density (BMD) in OVX rats. However, the use of VK alone did not appear to make any significant effect on BMD in OVX rats. We observed an increased excretion of urinary deoxypyridinoline (DPD), a marker of bone resorption, in OVX group, and statistically significant reduction of DPD when the animals were treated with VK, ALE, or both. There was no statistically significant difference in bone mineral content and body surface area. Was verified statistically significant difference in the thickness of compact bone in the different study groups. There was also a statistically significant reduction in wet weight and endometrium of OVX rats, demonstrating the effectiveness of ovariectomy. Therefore, the animal model used in this study efficiently mimicked estrogen deficiency induced by ovariectomy, resulting in increased bone resorption; treatment with ALE and VK+ALE increases BMD in OVX rats, while the VK alone does not produce this effect; treatment with ALE and VK reduces bone resorption in OVX rats, verified by the reduction in the excretion of DPD. / O osso é uma forma especializada de tecido conjuntivo que fornece suporte biomecânico e metabólico para todo o corpo. Para tanto, o tecido ósseo é muito dinâmico, apresentando-se em constante renovação. Sua integridade depende, portanto, do equilíbrio entre os processos de formação e reabsorção óssea. Ademais, desequilíbrios no processo de remodelamento ósseo podem resultar no desenvolvimento de doenças esqueléticas sistêmicas, como a osteoporose. A osteoporose é uma doença crônica e progressiva que afeta milhões de pessoas em todo o mundo. Somente no Brasil cerca de 10 milhões de pessoas sofrem de osteoporose. A deficiência hormonal estrogênica, induzida pela ovariectomia (OVX) em ratos, comprovadamente estimula o aumento da reabsorção óssea, principalmente em ossos longos e coluna vertebral, mimetizando o que acontece na osteoporose pós-menopausa. No presente trabalho foram utilizadas ratas OVX para se investigar a interação do alendronato (fármaco extensamente utilizado no tratamento da osteoporose) e da vitamina K (VK) (recentes investigações apontam possuir ação anabólica do tecido ósseo de pacientes osteoporóticas) no metabolismo osteomineral. Este estudo revelou que a administração de alendronato (ALE) e de VK juntamente com ALE (VK+ALE) produziu significante recuperação na densidade mineral óssea (DMO) de ratas OVX. No entanto, a utilização da VK isoladamente não pareceu exercer nenhum efeito significante na DMO de ratas OVX. Observou-se uma maior excreção de deoxipiridinolinas urinárias (DPD), marcador de reabsorção óssea no grupo OVX, e redução estatisticamente significante da DPD quando os animais foram tratados com VK, ALE ou ambas. Não houve diferença estatisticamente significante do conteúdo mineral ósseo e da área corporal. Também não foi verificada diferença estatisticamente significante na espessura do osso compacto nos diferentes grupos de estudo. Verificou-se ainda redução estatisticamente significante do peso úmido e do endométrio de ratas OVX, comprovando a eficiência da ovariectomia. Portanto, o modelo animal utilizado neste estudo mimetizou eficientemente a deficiência estrogênica induzida pela ovariectomia, resultando em aumento da reabsorção óssea; o tratamento com ALE e VK+ALE aumenta a DMO de ratas OVX, embora a VK isoladamente não apresente esse efeito; o tratamento com ALE e VK reduz a reabsorção óssea de ratas OVX, verificada pela redução na excreção de DPD.

Made available in DSpace on 2016-12-23T13:49:04Z (GMT). No. of bitstreams: 1 Dissertacao de Fernanda Scarpatti Pimentel.pdf: 2000878 bytes, checksum: cdfb57d1ceb94c6e6c0b410060dcfbfb (MD5) Previous issue date: 2010-07-29 / The bone is a specialized form of connective tissue that provides support for metabolic and biomechanical throughout the body. Thus, the bone is very dynamic, with constantly renewing itself. His integrity therefore depends on the balance between the processes of formation and resorption. The loss of this balance alters both the structure of organic matrix as bone mineralization. Moreover, imbalances in bone remodeling process may result in the development of systemic skeletal diseases such as osteoporosis. The osteoporosis is a chronic progressive disease that affects millions of people around the world. Only in Brazil some 10 million people suffer from osteoporosis. The hormone estrogen deficiency induced by ovariectomy (OVX) rats, demonstrably stimulates increased bone resorption, especially in long bones and spine, mimicking what happens in postmenopausal osteoporosis. In this work we used OVX rats to investigate the interaction of alendronate (a drug widely used to treat osteoporosis) and vitamin K (VK) (recent investigations have pointed anabolic bone tissue of osteoporotic patients) in the metabolism osteomineral. This study revealed that administration of alendronate (ALE) and VK with ALE (ALE+VK) produced significant recovery in bone mineral density (BMD) in OVX rats. However, the use of VK alone did not appear to make any significant effect on BMD in OVX rats. We observed an increased excretion of urinary deoxypyridinoline (DPD), a marker of bone resorption, in OVX group, and statistically significant reduction of DPD when the animals were treated with VK, ALE, or both. There was no statistically significant difference in bone mineral content and body surface area. Was verified statistically significant difference in the thickness of compact bone in the different study groups. There was also a statistically significant reduction in wet weight and endometrium of OVX rats, demonstrating the effectiveness of ovariectomy. Therefore, the animal model used in this study efficiently mimicked estrogen deficiency induced by ovariectomy, resulting in increased bone resorption; treatment with ALE and VK+ALE increases BMD in OVX rats, while the VK alone does not produce this effect; treatment with ALE and VK reduces bone resorption in OVX rats, verified by the reduction in the excretion of DPD / O osso é uma forma especializada de tecido conjuntivo que fornece suporte biomecânico e metabólico para todo o corpo. Para tanto, o tecido ósseo é muito dinâmico, apresentando-se em constante renovação. Sua integridade depende, portanto, do equilíbrio entre os processos de formação e reabsorção óssea. Ademais, desequilíbrios no processo de remodelamento ósseo podem resultar no desenvolvimento de doenças esqueléticas sistêmicas, como a osteoporose. A osteoporose é uma doença crônica e progressiva que afeta milhões de pessoas em todo o mundo. Somente no Brasil cerca de 10 milhões de pessoas sofrem de osteoporose. A deficiência hormonal estrogênica, induzida pela ovariectomia (OVX) em ratos, comprovadamente estimula o aumento da reabsorção óssea, principalmente em ossos longos e coluna vertebral, mimetizando o que acontece na osteoporose pós-menopausa. No presente trabalho foram utilizadas ratas OVX para se investigar a interação do alendronato (fármaco extensamente utilizado no tratamento da osteoporose) e da vitamina K (VK) (recentes investigações apontam possuir ação anabólica do tecido ósseo de pacientes osteoporóticas) no metabolismo osteomineral. Este estudo revelou que a administração de alendronato (ALE) e de VK juntamente com ALE (VK+ALE) produziu significante recuperação na densidade mineral óssea (DMO) de ratas OVX. No entanto, a utilização da VK isoladamente não pareceu exercer nenhum efeito significante na DMO de ratas OVX. Observou-se uma maior excreção de deoxipiridinolinas urinárias (DPD), marcador de reabsorção óssea no grupo OVX, e redução estatisticamente significante da DPD quando os animais foram tratados com VK, ALE ou ambas. Não houve diferença estatisticamente significante do conteúdo mineral ósseo e da área corporal. Também não foi verificada diferença estatisticamente significante na espessura do osso compacto nos diferentes grupos de estudo. Verificou-se ainda redução estatisticamente significante do peso úmido e do endométrio de ratas OVX, comprovando a eficiência da ovariectomia. Portanto, o modelo animal utilizado neste estudo mimetizou eficientemente a deficiência estrogênica induzida pela ovariectomia, resultando em aumento da reabsorção óssea; o tratamento com ALE e VK+ALE aumenta a DMO de ratas OVX, embora a VK isoladamente não apresente esse efeito; o tratamento com ALE e VK reduz a reabsorção óssea de ratas OVX, verificada pela redução na excreção de DPD

Leishmaniasis are infectious diseases caused by protozoa of the genus Leishmania, that are digenetic parasites alternating between an extracellular promastigote stage (in sand fly vector) and an intracellular amastigote stage (in mammalian host). Promastigote phagocytosis results in a macrophage respiratory burst in vitro, leading to the generation of reactive oxygen species (ROS) such as superoxide anion (O2 -), hydrogen peroxide (H2O2), singlete oxygen (1O2) and hydroxyl radical (OH). Thus, we aimed to evaluate in vitro ROS toxicity for L. L. chagasi promastigotes, as well as for their amastigote counterparts. To evaluate ROS toxicity for promastigotes, we selected 16 L. L. chagasi isolates (in log phase growth) and incubated them under increasing concentrations of menadione (0-750ìM) for 4 hours, after which we determined ROS viability for these parasites by quantifying the number of mobile forms. For ROS toxicity for amastigote L. L. chagasi, we infected J774.16, a murine macrophage cell line, with ROS susceptible and resistant L. L. chagasi (in stationary phase of growth) in cultures treated by LMNA, an iNOS inhibitor (to block the synthesis of nitric oxide), treatment with diethyldithiocarbamate (DETC), a SOD-1 inhibitor (to increase superoxide anion synthesis) as well as incubation with N-acetylcysteine, NAC ( an antioxidant).These infection experiments were conducted in 8 well plates in a 5:1 ratio (parasites/cell). Subsequently, we incubated these plates for 4, 24, 48 and 72 hours at 37oC and 5% CO2. After that, the plates were stained and the number of amastigotes (parasite burden) determined. We observed that 14 out 16 isolates treated with menadione showed 50% or more loss of their viability at concentrations varying from 15 to 750 ìM, whereas two of them exhibited even 70% or more viability at 750 mM. From ROS toxicity evaluation for L. L. chagasi amastigotes, we observed in J774.16 cultures infected by ROS susceptible and resistant L. L. chagasi a decrease in parasitic load for both isolates. This decrease in parasite burden was observed also in cultures treated by LMNA, an iNOS inhibitor. Inhibition of SOD by DETC also promoted a decrease in the number of amastigotes for both of these J774.16 cultures from 24 hour infection. The addition of NAC to these cultures increased the number of amastigotes for ROS resistant infected J774.16 cells but nor for those ROS susceptible infected cultures. These data indicate that damage on these amastigotes induced by DETC is oxidative. Thus, it is possible to conclude that reactive oxygen species are crucial toxic agents for L. L. chagasi as in promastigote form, as well as in amastigote form. / As leishmanioses sao doencas infecciosas causadas por parasitos do genero Leishmania. Leishmania sao protozoarios digeneticos, alternando entre as formas promastigota (flebotomineo) e amastigota (hospedeiro mamifero). A fagocitose de promastigotas desencadeia em macrofagos um gburst oxidativo h, gerando especies reativas do oxigenio (ROS) como o anion superoxido (O2 -), peroxido de hidrogenio (H202), o oxigenio singlete (1O2) e o radical hidroxila (OH). Assim, objetivamos avaliar in vitro a atividade leishmanicida de ROS para promastigotas de L.(L.) chagasi, bem como para suas respectivas formas amastigotas. Para a avaliacao da toxicidade de ROS para promastigotas, selecionamos 16 isolados de L.(L.) chagasi (em fase log de crescimento), incubando-os sob concentracoes crescentes de menadiona (0-750 ÊM) por um periodo de 4h, ao fim do qual determinamos a viabilidade desses parasitos, quantificando o numero de formas moveis. Na avaliacao da acao leishmanicida de ROS para as formas amastigotas de L. L. chagasi, infectamos uma linhagem celular de macrofagos murinos J774.16 com um isolado resistente e dois isolados susceptiveis a ROS (na proporcao 5:1 parasitos/celulas) em culturas com LMNA, inibidor de iNOS, (para bloquear a sintese de oxido nitrico), incubadas com o inibidor da enzima SOD-1, dietilditiocarbamato, DETC (para aumentar a producao de O2 -) e com N-acetilcisteina, NAC (um antioxidante) em placas de 8 pocos e incubadas por 4, 24, 48 e 72 horas. Ao termino de cada incubacao, coramos as placas com panotipo, para determinacao do numero de amastigotas (carga parasitaria). A partir da exposicao de promastigotas a concentracoes crescentes de menadiona, observamos que dos 16 isolados avaliados, 14 deles apresentaram perdas de 50% ou mais de suas viabilidades entre concentracoes de 15 a 750 ÊM de menadiona (formas susceptiveis a ROS), enquanto apenas dois deles apresentaram 70% ou mais de viabilidade a 750 ÊM de menadiona (formas resistentes a ROS). Na avaliacao da toxicidade de ROS para as formas amastigotas, observamos nas culturas de celulas J774.16 infectadas por L. L. chagasi susceptiveis e resistente a ROS diminuicao na carga parasitaria de ambos os isolados a partir do periodo de 48 horas. Para as culturas incubadas com DETC, observamos a reducao dos numeros de amastigotas para essas culturas, a partir do tempo de 24 horas de infeccao. A adicao de NAC a essas culturas reverteu a carga parasitaria das culturas infectadas pelo isolado resistente, mas nao as que foram infectadas pelos isolados susceptiveis a ROS, indicando que o dano induzido por DETC sobre essas amastigotas e oxidativo. Assim, e possivel afirmar que as especies reativas do oxigenio sao importantes agentes toxicos para promastigotas e amastigotas de L. L. chagasi.

INTRODUÇÃO: A fibrilação atrial (FA) é a arritmia cardíaca mais comum e está associada a uma significativa morbidade e mortalidade. A sua prevalência aumenta marcadamente com a idade. A terapia com anticoagulantes orais tem sido a base de tratamento e prevenção de eventos tromboembólicos em pacientes com FA. Entretanto, a anticoagulação oral em idosos pode ser desafiadora devido à vários fatores, como alterações orgânicas funcionais, risco aumentado de sangramento e eventos isquêmicos, presença de comorbidades, polifarmácia e uma menor aderência ao tratamento. OBJETIVOS: Avaliar a frequência de tromboembolismo e complicações hemorrágicas em pacientes muito idosos (idade >= 85 anos) em uso de varfarina; avaliar tempo na faixa terapêutica (TTR), causas do INR fora da faixa, escores de CHADS2 e CHA2DS2 - VASc, comorbidades associadas e causas de mortalidade. METODOS: análise retrospectiva de pacientes que iniciaram o tratamento com varfarina com uma idade >= 85 anos, entre abril de 1999 e setembro de 2013, controlados em uma clínica de anticoagulação oral. RESULTADOS: foram incluídos 164 pacientes; 51% eram do sexo masculino e a idade média de início e fim do tratamento com varfarina foram de 86,8 e 89,7 anos, respectivamente. A indicação mais comum para o uso de ACo foi a fibrilação atrial (86%). O seguimento médio foi de 34,6 ± 23 meses. O CHADS2 e CHA2DS2 - VASc médio dos pacientes foi 2,78 e 4,7, respectivamente. O tempo na faixa terapêutica (TTR) foi de 58,6%. A polifarmácia esteve presente em 78% dos pacientes. De acordo com as estimativas de Kaplan-Meier, a probabilidade livre de TE e sangramento grave foi de 93,5% e 90,5% em três anos, respectivamente. Quando analisados esses dois desfechos combinados, a probabilidade livre de tromboembolismo e sangramento grave foi de 83,4% em três anos. CONCLUSÃO: nesse estudo, o uso de um antagonista da vitamina k (varfarina) em pacientes com idade >= 85 anos esteve associado a um baixo risco de tromboembolismo e sangramento grave durante o período de seguimento. / INTRODUCTION: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated to a significant morbidity and mortality. Its prevalence strongly increases with aging. Therapy with oral anticoagulants (OAC) has been the basis of treatment and prevention of thromboembolic events in patients with AF. However, oral anticoagulation in the elderly can be challenging due to various factors such as the alteration of organic functions, greater risk of bleeding and ischemic events, presence of comorbidity, polypharmacy and a lower adherence to treatment. OBJECTIVES: Evaluate the frequency of thromboembolism and hemorrhagic complications in very elderly patients (aged >= 85 years) in use of warfarin; evaluate time in therapeutic range (TTR), causes of INR outside the range, scores of CHADS2 and CHA2DS2 - VASc, associated comorbidities and cause of death. METHODS: Retrospective analysis of patients who initiated treatment with warfarin at aged >=85 years, between April of 1999 and September of 2013, controlled in an oral anticoagulation clinic. RESULTS: A total of 164 patients were included in the study; 51% were males and the mean ages at the start and end of the treatment with warfarin were of 86,8 and 89,7 years, respectively. The most common indication for the use of OAC was atrial fibrillation (86%). The mean follow-up was of 34,6 ± 23 months. The mean CHADS2 and CHA2DS2 - VASc of patients was 2,78 and 4,7, respectively. The time in therapeutic range (TTR) was of 58,6%. Polypharmacy was present in 78% of patients. According to the Kaplan-Meier estimates, the survival curve of TE and severe bleeding was of 93,5% and 90,5% in three years, respectively. When these two combined outcomes are analyzed, the survival curve of thromboembolism and severe bleeding was of 83,4% in three years. CONCLUSION: In this study, the use of one vitamin K antagonist (warfarin) in patients aged >= 85 years was associated to a low risk of thromboembolism and severe bleeding during the follow-up period.

Gas6 est une protéine sécrétée gamma-carboxylée de façon dépendante à la vitamine K et fonctionne comme un ligand pour les récepteurs tyrosine kinase de la famille TAM : TYRO3, AXL et MERTK. Plusieurs études chez l’humain suggèrent un rôle potentiel de Gas6 dans la résistance à l’insuline et l’obésité. Cependant, le mécanisme par lequel Gas6 influence la sensibilité à l’insuline est toujours inconnu. Selon nos résultats préliminaires, nous avons posé l’hypothèse que GAS6 régule la sensibilité à l’insuline dans le muscle et le tissu adipeux via son interaction avec ses récepteurs à la surface des cellules. Méthodes et résultats : Nous avons observé qu’Axl est le récepteur de Gas6 le plus exprimé dans les adipocytes et les myocytes. De plus, nous avons déterminé qu’AXL et sa cible AKT sont phosphorylés dans les C2C12 différenciées suivant une stimulation avec la protéine Gas6 recombinante. Également, ces événements de phosphorylation sont inhibés par la molécule LDC1267, un inhibiteur des récepteurs TAM. Ensuite, les souris Gas6-/- montrent une augmentation de la tolérance au glucose et de la sensibilité à l’insuline. En contraste, les souris transgéniques surexprimant Gas6 présentent une résistance à l’insuline en comparaison avec les souris de type sauvages. Pour investiguer en profondeur les événements moléculaires en aval de Gas6 et ses récepteurs, nous avons caractérisé le transcriptome dépendant de la signalisation Gas6-récepteurs TAM dans les myotubes en utilisant une expérience de séquençage d’ARN. De façon intéressante, nous avons identifié que plusieurs molécules cibles de la signalisation de l’insuline sont modifiées par Gas6. Ensemble, ces résultats supportent la notion que Gas6 est impliqué dans la régulation de la sensibilité à l’insuline in vivo. Cette fonction se produit lors de son interaction avec au moins un de ses récepteurs, soit Axl, à la surface des myotubes. / Introduction: Gas6 is a secreted protein which is gamma-carboxylated in a vitamin K dependent manner and functions as ligand for the TAM family of receptor tyrosine kinases: TYRO3, AXL and MERTK. A few studies in humans suggest a potential role for Gas6 in insulin resistance and obesity. Nevertheless, the mechanisms by which Gas6 influences insulin resistance remain unknown. Based on our preliminary data, we hypothesized that Gas6 regulates insulin sensitivity in muscle and adipose tissue through its interaction with its receptors. Methods and Results: We observed that Axl is the most highly expressed Gas6 receptor in adipocytes and myocytes. Moreover, we found that Axl and its downstream target AKT are phosphorylated in C2C12 myotubes following stimulation with recombinant Gas6. Importantly, these phosphorylation events are abrogated when cells where pre-treated with LDC1267, a TAM pharmacological inhibitors. In addition, Gas6-/- mice display an improved glucose tolerance, associated with increased insulin sensitivity when compared to wild-type mice. In contrast, Gas6 transgenic mice characterized by increased circulating Gas6 levels (ApoE-Gas6 Tg) have reduced insulin sensitivity. To further investigate the molecular events downstream of Gas6 and of its receptor in muscle cells, we characterized the Gas6/Axl-dependent transcriptome in myotubes using RNAseq. Interestingly, we found that key regulators of the insulin signaling pathway were modulated by Gas6 and Axl. Conclusion and Relevance: Together, these results support the notion that Gas6 is implicated in the regulation of insulin sensitivity in vivo. This function of Gas6 occurs through its interaction with Axl at the surface of myocytes.

L’apport en vitamine K a été identifié comme un facteur influençant la stabilité de l’anticoagulothérapie à long terme. Des études cliniques ont montré que les patients recevant un supplément de vitamine K (100 à 150 μg/jour) bénéficiaient d’une amélioration de la stabilité de l’anticoagulothérapie. Dans le but de vérifier si un effet bénéfique similaire peut être obtenu grâce à une augmentation de l’apport de vitamine K à partir de la diète, un essai contrôlé randomisé de 24 semaines a été mené. Les patients randomisés dans le groupe d’intervention ont participé à des ateliers proposant des recommandations nutritionnelles afin d’augmenter leur apport en vitamine K d’au moins 150 μg/jour. Les patients du groupe contrôle ont participé à des ateliers distincts recommandant une alimentation équilibrée. La stabilité de l’anticoagulothérapie a été définie par le pourcentage de temps passé dans la fenêtre thérapeutique (TTR≥70%) entre les semaines 4 et 24. L’analyse basée sur l’intention de traitement a montré que le pourcentage des participants qui répondaient aux critères de stabilité à l’anticoagulation étaient 44,4% et 27,3% pour le groupe d’intervention et le groupe contrôle, respectivement (p=0,22). L’analyse conforme au protocole a accentué la différence entre les groupes intervention et contrôle (52,2% et 27,3%, respectivement (p=0,088)). Les deux analyses ont montré que l’apport moyen de vitamine K calculé entre les semaines 6 et 24 était supérieur dans le groupe d’intervention par rapport au groupe contrôle (p=0,001). Cette étude tend à appuyer l’hypothèse selon laquelle un apport quotidien élevé de vitamine K améliore la stabilité de l’anticoagulothérapie. / Vitamin K intake has emerged as an important factor in influencing the stability of long-term anticoagulation therapy. Clinical trials have shown that patients receiving a vitamin K supplement (100 - 150 μg/d) present improvements in the stability of their anticoagulant therapy. Thus, a 24-week randomized controlled trial was conducted to verify whether similar beneficial effects could be achieved by increasing daily vitamin K intake through the diet. Patients randomly assigned to the intervention group attended workshops that provided dietary counsel to increase their vitamin K intake by ≥ 150 μg/day. Patients in the control group participated in distinct workshops providing general advice on a balanced diet. The stability of anticoagulation therapy was defined as the percentage of time spent in the therapeutic range (TTR ≥ 70%) during weeks 4 through 24 of the experimental period. Intention to treat analysis showed that the percentage of participants who benefited from an improvement in the stability of anticoagulation therapy was greater in the intervention group than the control group (44.4% vs 27.3% respectively; p=0.22). Per protocol analysis accentuated the difference between groups i.e. 52.2% vs 27.3% in intervention and control group respectively (p=0.088). Both analyses showed that the mean vitamin K intake calculated during weeks 6 through 24 was higher in the intervention than in the control group (p=0.001). The study tends to support the hypothesis that a high daily vitamin K intake improves the anticoagulation stability of warfarin-treated patients.