Aplicación tópica de ácido tranexámico en urología: ¿Una alternativa de manejo? / Topical Application of Tranexamic Acid in Urology: An Alternative Management?

Los agentes antifibrinolíticos, como el ácido tranexámico, por medio de su administración endovenosa se usan en distintos procedimientos quirúrgicos para prevenir la pérdida de sangrado perioperatorio.[1] Este medicamento es un derivado sintético análogo de la lisina que bloquea los sititos de unión de la lisina en el plasminógeno, inhibiendo su conversión a plasmina e interfiriendo en la fibrinólisis.[2] La aplicación del ácido tranexámico para disminuir el riesgo de sangrado ha sido utilizado en procedimientos urológicos como la resección transuretral prostática (RTUP), prostatectomía radical y nefrolitotomía percutánea (NLP),[3] [4] [5] también se emplea para disminuir las hematurias persistentes en pacientes con poliquistosis renal y en otras hematurias macroscópicas de origen urológico.

Antifibrinolytic agents, such as tranexamic acid, by intravenous administration are used in various surgical procedures to prevent perioperative bleeding loss.[1] This drug is a synthetic lysine analog derivative that blocks the lysine binding sites on plasminogen, inhibiting its conversion to plasmin and interfering with fibrinolysis.[2] The application of tranexamic acid to reduce the risk of bleeding has been used in urological procedures such as transurethral resection of the prostate (TURP), radical prostatectomy and nephrolithotomy. The application of tranexamic acid to reduce the risk of bleeding has been used in urological procedures such as transurethral resection of the prostate (TURP), radical prostatectomy and percutaneous nephrolithotomy (PNL),[3] [4] [5] it is also used to reduce persistent hematuria in patients with polycystic kidney disease and other macroscopic hematuria of urological origin.

Análise comparativa dos efeitos do mel, do óleo-serina de copaíba e de um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) na cicatrização por segunda intenção, em ratos / Comparative analysis of the effects of honey, copaiba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) on second intention healing, in rats

RESUMO Objetivo: comparar a cicatrização, por segunda intenção, sob os efeitos da aplicação tópica de mel, óleo-resina de copaíba e um produto comercial (fibrinolisina, desoxirribonuclease e cloranfenicol) a um grupo controle, em ratos. Métodos: ressecção de pele, com 1cm de diâmetro, foi realizada no dorso de 40 ratos alocados em quatro grupos de dez animais. Todas as feridas foram limpas, diariamente, com 2ml de solução de NaCl 0,9%. O primeiro grupo (controle - GC) ficou restrito a tal procedimento. Nas feridas do segundo (GM), terceiro (GO) e quarto grupos (GF), após limpeza, aplicou-se, respectivamente, 1ml de mel, 1ml de óleo-resina de copaíba e 1ml de creme contendo fibrinolisina, desoxirribonuclease e cloranfenicol. Ocluíram-se as feridas com gaze estéril. Imediatamente após a incisão e nos dias três, sete e 14 do experimento, as feridas foram copiadas e, usando planimetria, analisou-se a contração. Após a eutanásia, a histologia foi utilizada para avaliação da reação inflamatória e do colágeno nas cicatrizes. Resultados: a redução da área da ferida do GM (p=0,003), GO (p=0,011) e GF (p=0,002) foram superiores ao do GC. A quantidade de colágeno tipo I presente no GM e no GO foi superior aos grupos GC e GF (p<0,05). Houve predominância do estágio inflamatório crônico no GM (p=0,004), GO (p<0,001) e GF (p=0,003) quando comparados ao GC. Conclusão: o uso tópico do mel e do óleo-resina de copaíba aumenta a contração da ferida, a presença de colágeno tipo I e acelera a cicatrização.

ABSTRACT Objective: to compare the healing by second intention under the effects of topical application of honey, copaíba oil-resin and a commercial product (fibrinolysin, deoxyribonuclease and chloramphenicol) with a control group in rats. Methods: we carried out a skin resection, 1cm in diameter, on the back of 40 rats allocated to four groups of ten animals. All wounds were cleaned daily with 2ml of 0.9% NaCl solution. The first group (control - GC) was restricted to such procedure. In the wounds of the second (GM), third (GO) and fourth groups (GF), after cleaning, we respectively applied 1ml of honey, 1ml of copaíba oil-resin and 1ml of cream containing fibrinolysin, deoxyribonuclease and chloramphenicol. The wounds were occluded with sterile gauze. Immediately after the incision and on days three, seven and 14 of the experiment, the wounds were copied and contraction was analyzed using planimetry. After euthanasia, we histologically evaluated the inflammatory reaction and collagen in the scars. Results: the reduction of the wound area of GM (p=0.003), GO (p=0.011) and GF (p=0.002) were higher than the GC. The amount of type-I collagen present in GM and GO was higher than in GC and GF groups (p<0.05). There was a predominance of chronic inflammatory stage in GM (p=0.004), GO (p<0.001) and GF (p=0.003) when compared with GC. Conclusion: the topical use of honey and copaíba oil-resin increases wound contraction, the presence of type-I collagen and accelerates healing.

Initial experience with ocriplasmin in the treatment of vitreomacular traction / Experiência inicial com ocriplasmina no tratamento da tração vitreorretiniana

ABSTRACT This study aimed to report the clinical and structural outcomes of intravitreal ocriplasmin in the treatment of vitreomacular interface disorders in two tertiary centers in Brazil. A retrospective study was performed by reviewing medical records and spectral domain optical coherence tomography (SD-OCT) findings of seven patients who were treated with a single ocriplasmin injection. A total of 57.14% of patients achieved resolution of vitreomacular traction as evidenced by SD-OCT. Regarding our functional results, 87.71% maintained or improved visual acuity after follow-up. To the best of our knowledge, this is the first study reporting initial results of ocriplasmin therapy in Brazil.

RESUMO O objetivo desse estudo é relatar os resultados iniciais, tanto do ponto de vista funcional quanto anatômico, no tratamento das doenças da interface vítreo-macular com a ocriplasmina em 2 serviços terciários no Brasil. Um estudo retrospectivo foi realizado através de revisão de prontuários, além de análise de achados em tomografia de coerência óptica de domínio espectral (SD-OCT) em 7 pacientes tratados com uma única injeção intravítrea de ocriplasmina. Em nosso estudo 57,14% dos pacientes apresentaram resolução da tração vítreo-macular no SD-OCT. Em relação aos resultados funcionais, 87,71% dos pacientes mantiveram, ou melhoraram sua acuidade visual durante o acompanhamento. Para nosso conhecimento, trata-se do primeiro estudo em nosso país, mostrando resultados iniciais com ocriplasmina em pacientes tratados no Brasil.

Alteraciones de la hemostasia en el síndrome drepanocítico / Hemostasis alterations in sickle cell syndrome

El síndrome drepanocítico (SD) comprende un grupo de anemias hemolíticas hereditarias de tipo multisistémico asociadas a la hemoglobina S. Los pacientes que padecen este síndrome tienen un mayor riesgo, en comparación con individuos sanos, de presentar accidentes cerebrovasculares, hipertensión pulmonar, necrosis avascular de articulaciones, síndrome torácico agudo y complicaciones durante el embarazo, asociados a un estado de hipercoagulabilidad inducido por alteraciones en los diferentes componentes de la hemostasia, que incluyen la activación del endotelio y de los sistemas plaquetario, de la coagulación y de la fibrinólisis. Esta revisión resume las alteraciones en la hemostasia reportadas en los pacientes con SD, en los cuales se ha demostrado: mayor interacción de células endoteliales con leucocitos, hematíes y plaquetas; aumento de la expresión de proteínas de adhesión, como el factor von Willebrand y sus multímeros de alto peso molecular; aumento de la adhesión y la agregación plaquetaria y de la expresión de proteínas en sus membranas. En el sistema de coagulación se ha detectado aumento en la expresión del factor tisular (FT) en micropartículas derivadas de diferentes células, aumento de marcadores de activación de este sistema, entre estos los fragmentos 1.2 de la protrombina y los complejos trombina-antitrombina y una disminución de las proteínas C y S que actúan como anti-coagulantes. Adicionalmente, se han encontrado aumentados los marcadores de activación del sistema fibrinolítico como los dímeros D y los complejos plasmina/antiplasmina. Todas estas manifestaciones favorecen la aparición de complicaciones trombóticas, implicadas en el deterioro de la calidad de vida de los pacientes. Se recomienda implementar en el diagnóstico y seguimiento de esta enfermedad, la determinación de variables del sistema hemostático, con el fin de identificar alteraciones en etapas tempranas y aplicar terapias que puedan prevenir complicaciones trombóticas.

Sickle cell syndrome (SCS) includes a group of congenital hemolytic anemias associated to the presence of hemoglobin S, which is characterized by acute pain episodes and progressive damage of different organs. Some patients with sickle cell syndrome have shown, when compared with healthy individuals, an increased risk of presenting stroke, pulmonary hypertension, avascular necrosis of joints, acute chest syndrome and pregnancy complications, associated to a hypercoagulable state induced by alterations in different components of hemostasis, such as changes that include activation of the endothelium, platelet activity, coagulation and fibrinolytic systems. This paper compiles hemostasis disorders, associated with thrombotic manifestations, reported until now in sickle cell syndrom. These patients have an increase in activation markers of the coagulation system, such as prothrombin fragment 1.2, thrombin-antithrombin complex, etc., depletion of natural anticoagulant proteins, abnormal activation of the fibrinolytic system and increased tissue factor expression. Similarly, abnormal expression of glycoproteins and increased adhesion and platelet aggregation have been reported. All these alterations produce a hypercoagulable state, which induces, among other things, the appearance of thrombotic complications. In view of the importance of controlling the different complications that can occur in patients with sickle cell syndrome, we recommend the implementation, in diagnosis and monitoring studies, of the evaluation of the different components of the hemostatic system, identifying alterations at an early stage and applying effective treatments to prevent thrombotic complications.

Plasmin degradation of the alpha chain of fibrinogen/fibrin: improved activation constant and activity determination in assays for tissue plasminogen activator / Degradación por la plasmina de la cadena alfa del fibrinógeno/fibrina: mejoría de la constante de activación y determinación de la actividad en ensayos para el activador del plasminógeno tisular

Objectives. The aim of this investigation was to increase the efficiency of ternary complex formation (fibrin-plasminogen-tissue-plasminogen activator) in the degradation process of the three-dimensional soluble fibrin monomer. Materials and methods. Fibrinogen was purified from human plasma by repeating precipitation six times, using different concentrations of cold ethanol. Fibrinogen was converted to DesAAfibrinogen by degradation with bathroxobin. Human plasminogen was purified by affinity and ion-exchange chromatography, and activated to plasmin by incubation with urokinase. Digested DesAAfibrinogen was prepared by controlled digestion with plasmin. Results. This study demonstrates that the α-chains of DesAAfibrinogen sterically hinder the formation of the ternary complex and are first degraded by plasmin. The degradation of fibrin(ogen) facilitates the in vitro determination of tissue plasminogen activator activity. Finally, release of fibrinopeptide A from bathroxobin-cleaved fibrinogen was confirmed, optimized and evaluated by various methods. Conclusions. Use of digested desAAfibrinogen with plasmin yielded a more stable activation constant of the ternary complex than that of undigested DesAAfibrinogen.

Objetivos. El propósito de la presente investigación fue incrementar la eficacia de la formación del complejo terciario (fibrina-plasminógeno-activador tisular del plasminógeno) en el proceso de degradación de la estructura tridimensional del monómero de fibrina soluble. Materiales y métodos. El fibrinógeno fue purificado de plasma humano, por seis precipitaciones repetidas, con diferentes concentraciones de etanol frío. El fibrinógeno fue convertido a desAAfibrinógeno por degradación con batroxobina. El plasminógeno humano fue purificado por cromatografías de afinidad e intercambio iónico y activado a plasmina con uroquinasa. El desAAfibrinogeno digerido fue preparado por digestión controlada con plasmina. Resultados. Este estudio demuestra que la cadena α del desAAfibrinógeno, dificulta la formación del complejo terciario, por impedimentos estéricos, por lo cual la cadena α se sometió a hidrólisis controlada con plasmina, facilitando así la determinación in vitro de la actividad del activador tisular del plasminógeno. Finalmente, la liberación del fibrinopéptido A por hidrólisis del fibrinógeno con batroxobina, fue confirmada, optimizada y evaluada por varios métodos. Conclusiones. El uso de desAAfibrinogeno digerido con plasmina da una constante de activación más estable en la formación del complejo terciario que el desAAfibrinógeno no digerido (fibrina-plasminogeno- activador tisular del plasminógeno).

Determinación de los parámetros cinéticos de la plasmina porcina y comparación con la humana / Porcine plasmin: determination of kinetic parameters and comparison with human plasmin

El plasminógeno es el zimógeno de la plasmina, enzima relacionada con la disolución del coágulo sanguíneo. Estudios con plasminas de diferentes especies animales han demostrado mayor afinidad que la plasmina humana por sustratos análogos hechos exclusivamente para ella. Así lo confirman la activación y cinética del sistema plasminógeno/plasmina porcino, que hasta el presente no se habían determinado ni comparado con el humano. En este trabajo se utilizaron, para la purificación del plasminógeno, cromatografía de afinidad y cambio iónico; se utilizó urocinasa para la activación del plasminógeno a plasmina y se determinaron los parámetros cinéticos con el sustrato cromógeno S-2251. Los terminales-N se determinaron por el método de degradación de Edman. La plasmina porcina demostró mayor afinidad (Km) por el sustrato que la plasmina humana, 1,55 y 5,3 mM respectivamente, mientras que la plasmina humana mostró mayor velocidad de conversión del sustrato a producto (0,1 UA/ seg) que la porcina (0,033 UA/seg). Los terminales-N se diferenciaron en los aminoácidos 1 y 3, DPPDDY (porcino) y EPLDDY (humano).

Plasminogen is the zymogen of plasmin, enzyme that is responsible for dissolving blood clots. Studies with plasmins from different animals have demonstrated higher affinity than human plasmin for substrate analogs made exclusively for the latter. This has been confirmed by the activation and kinetics of the porcine plasminogen/plasmin system, which had so far not been determined or compared with the human system. The methods used in this study for purification of plasminogen were affinity and ion exchange chromatographies. Urokinase was used for the activation of plasminogen to plasmin and kinetic parameters were determined with the chromogenic substrate S-2251. The N-terminals were determined by the Edman degradation method. Porcine plasmin showed higher affinity (Km) than human plasmin for the chromogenic substrate, 1.55 mM and 5.3 mM, respectively; contrariwise, human plasmin demonstrated higher velocity in the substrate to product conversion: 0.1 UA/seg) vs. 0.033 UA/seg. The N-terminals differed in the amino acids 1 and 3: DPPDDY (for porcine) and EPLDDY (for human).

Surface-expressed enolases of Plasmodium and other pathogens

Enolase is the eighth enzyme in the glycolytic pathway, a reaction that generates ATP from phosphoenol pyruvate in cytosolic compartments. Enolase is essential, especially for organisms devoid of the Krebs cycle that depend solely on glycolysis for energy. Interestingly, enolase appears to serve a separate function in some organisms, in that it is also exported to the cell surface via a poorly understood mechanism. In these organisms, surface enolase assists in the invasion of their host cells by binding plasminogen, an abundant plasma protease precursor. Binding is mediated by the interaction between a lysine motif of enolase with Kringle domains of plasminogen. The bound plasminogen is then cleaved by specific proteases to generate active plasmin. Plasmin is a potent serine protease that is thought to function in the degradation of the extracellular matrix surrounding the targeted host cell, thereby facilitating pathogen invasion. Recent work revealed that the malaria parasite Plasmodium also expresses surface enolase, and that this feature may be essential for completion of its life cycle. The therapeutic potential of targeting surface enolases of pathogens is discussed.

Activación y determinación de parámetros cinéticos de la plasmina humana y Ovis aries / Activation and comparative kinetics of Ovis aries plasmin with human plasmin

Objetivo. Comparar las cinéticas y activaciones, unificar las purificaciones y determinar las secuencias de los terminales-N de los plasminógenos Ovis aries y humano. Materiales y métodos. Los plasminógenos fueron purificados por el mismo método: cromatografías de afinidad e intercambio iónico, activados con urocinasa, la secuencia de los terminales-N se realizó por el método de Edman Resultados. La afinidad de la plasmina Ovis aries por el sustrato cromogénico fue de 0.45 mM, 11.8 veces mayor que la afinidad de la plasmina humana (5.3 mM). Conclusiones. Se confirma y unifica el método de purificación de los plasminógenos del plasma, para todos los mamíferos. La alta afinidad de la plasmina Ovis aries confirma una mayor afinidad de las plasminas animales por el sustrato cromogénico, en comparación con la plasmina humana.

Efecto de los anticuerpos antifosfolipídicos en la formación y degradación de la malla de fibrina en pacientes con aborto recurrente / Effect of antiphospholipid antibodies on the formation and lysis of fibrin network in patients with recurrent miscarriage

En el presente trabajo se estudió el proceso de formación y disolución de la malla de fibrina y la generación de plasmina en un grupo de pacientes con aborto recurrente (AR) debido a la presencia de anticuerpos antifosfolipídicos (N= 10), mujeres con AR sin el síndrome antifosfolipídico (SAF) (N= 6) y se comparó con un grupo de mujeres sanas (N= 8). Del grupo de pacientes estudiadas con SAF, nueve fueron positivas para anticuerpos anticardiolipina (aCL), cinco para la anti-b2-glicoproteína I (anti-b2GPI), cuatro para ambos anticuerpos, una para anticuerpos antiprotrombina (aPT) y anticoagulante lúpico (AL). El proceso de formación de la fibrina y su disolución fue estudiado por turbidimetría y la generación de plasmina mediante sustrato cromogénico S2251. Las curvas de polimerización de la(s) paciente(s) con AR sin SAF y AL presentaron un incremento en la pendiente y turbidez final, comparado con las del grupo control de mujeres sanas. La velocidad de disolución del coágulo fue mayor en la paciente con AL (21 ± 0) 10-4 DDO/seg y en las AR sin SAF (19,6 ± 5,7) 10-4 DDO/seg, comparado con el grupo control (14,5 ± 2,8) 10-4 DDO/seg. La generación de plasmina estuvo incrementada solamente en las AR sin SAF (85 ± 24%) comparado con 52 ± 3% en el grupo control, p= 0,005. Los cambios observados en el proceso de polimerización y fibrinólisis de la(s) paciente(s) con AR sin SAF y AL pudieran estar relacionados con el incremento en los niveles de fibrinógeno, mientras que los de la generación de plasmina con la entidad mórbida.

The present work was intended to study the process of fibrin formation and lysis and plasmin generation in a group of patients with recurrent miscarriage (RM), due to the presence of antiphospholipid antibodies (N= 10); as well as in women with RM without the antiphospholipid syndrome (APS) (N= 6), compared with those of a group of healthy women (N= 8). In the group of patients with APS, nine were positive for antibodies against cardiolipin (aCL), five for anti-b2-glycoprotein I (anti-b2GPI), four for both antibodies, and one for antibodies against prothrombin (aPT) and lupus anticoagulant (LA). Fibrin formation and lysis was followed by turbidity and plasmin generation using chromogenic substrate S2251. The polymerization curves from RM patients without APS and the LA patient showed an increased slope and maximum turbidity compared to those of the control group. The speed of lysis was higher in the LA patient (21 ± 0) 10-4 DOD/seg and the RM patients without APS (19.6 ± 5.7) 10-4 DDO/seg, compared to that of the control group (14.5 ± 2.8) 10-4 DDO/seg. Plasmin generation increased only in RM patients without APS (85 ± 24%) against the control group (52 ± 3%), p= 0.005. The changes observed in the fibrin polymerization and lysis process of women with RM without APS and LA seem to be related to their higher fibrinogen levels, while the increased plasmin generation was related to the patients´ morbidity.

Avances recientes en la fisiopatología del edema en el síndrome nefrótico / New insights into the pathophysiology of edema formation in nephrotic syndrome

El edema es una manifestación clínica frecuente del síndrome nefrótico; sin embargo, el mecanismo fisiopatológico responsable de la retención de sodio ha sido un tema de intenso debate por décadas. Muchas observaciones clínicas y experimentales no apoyan a la teoría clásica o del underfill de la formación del edema en el síndrome nefrótico. El edema propio del síndrome nefrótico se produce por un defecto renal intrínseco en la excreción de sodio y es independiente de factores sistémicos, como la hipoalbuminemia, la disminución del volumen arterial efectivo o el hiperaldosteronismo secundario. El sitio en la nefrona donde se produce la retención de sodio en el síndrome nefrótico es el túbulo colector cortical. La activación del canal de sodio epitelial en el túbulo colector cortical es responsable de la retención de sodio en el síndrome nefrótico. Una barrera glomerular defectuosa propia del síndrome nefrótico permitiría el paso de enzimas proteolíticas o sus precursores que, a su vez, activarían el canal de sodio epitelial y, de esa manera, causarían la retención de sodio y el edema.

Edema is a common clinical manifestation of nephrotic syndrome; however, the pathophysiological mechanism of sodium retention in nephrotic syndrome remains an area ofintense debate over decades. Several clinical and experimental observations argue against the classical or ôunderfillõ hypothesis of edema formation in nephrotic syndrome. Edema formation in nephrotic syndrome is probably due toan intrinsic inability of the kidney to excrete salt and is independent of systemic factors (i.e. hypoalbuminemia, decreased ôeffectiveõ arterial blood volume, and secondary hyperaldosteronism). The nephron site of sodium retention in nephrotic syndrome is the cortical collecting duct. Activation of the epithelial sodium channel in the cortical collecting duct is responsible for sodium retention in nephrotic syndrome. A defective glomerular filtration barrier in nephrotic syndrome allows passage of proteolytic enzymes or their precursors that have the ability to activate the epithelial sodium channel with the subsequent sodium retention and edema.

Padronização de dosagem de produto de degradação fibrinogênio/fibrina humano / Human fibrin/fibrinogen degradation product dosage standardization

A hemostasia contribui para integridade e fluidez sanguinea. Após ativação de plaquetas, fatores da coagulação e células endoteliais ocorrem reações enzimáticas gerando trombina e fibrina, principal constituinte do trombo. A plasmina remove o coágulo degradando a fibrina em produtos solúveis (sistema fibrinolítico) e fragmentados (Produtos de Degradação da Fibrina - PDF) onde o Dímero D é o mais estável. Por isso torna-se um importante indicador do risco vascular. Realizaram-se 2 protocolos: LAMB F (Fibrinogênio) e Lamb D (Fragmentado D) produzindo 2786 hibridos com atividade anti PDF. Os hibridos selecionados foram submetidos à técnica de immunoblotting onde foram utilizadas as fontes de antigenos diferentes (Fib comercial, Fib purificado in house, Fragmento D, líquido de drenagem rico em PDF. Com base no reconhecimento das frações protéicas, selecionou-se 2 híbridos (LAMB F1 - 120 e LAMB D3-6), que foram clonados e expandidos em cultura (in vitro) e ascite (in vivo) para obtenção de altas concentrações de AcMm. O líquido ascítico foi purificado (coluna de afinidade)e os anticorpos acoplados em esferas (beads) de agarose. Testes qualitativos foram realizados em paralelo com o produto comercial (Dimer Test Dade Behring) utilizando 20 amostras de pacientes (15 PDF normal e 05 PDF alterado). Os resultados mostraram 100% de concordância entre o produto comercial e os anticorpos anti-PDF produzido no laboratório.

Does the evaluation of coagulation factors contribute to etiological diagnosis of pleural effusions?

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.

Matriz extracelular na aorta ascendente humana: quantificação morfométrica do colágeno em aortas normais e análise topográfica da matrilisina, estromelisia e plasmina em dissecções e aneurismas não-inflamatórios / Extracellular matriz in the human ascending aorta: morphometric quantification of collagen in normal aortas and topographic analysis of matrilysin, stromelysin and plasmin in dissection and non inflammatory aneurisms

Nas dissecções e aneurismas não-inflamatórios da aorta ascendente há aumento de material mucóide (aspecto que corresponde a proteoglicanos). Analisamos por reações de imunoperoxidase a distribuição de estromelisina (MMP-7), matrilisina (MMP-3) e plasmina, enzimas que agem em proteoglicanos, em cortes de aortas humanas com tais doenças e em controles. Nos casos com qualquer dessas doenças MMP-7 e MMP-3 se acumularam nas áreas de depósito mucóide, e a plasmina ao redor delas. Tais enzimas podem estar envolvidas nessas doenças. Adicionalmente, avaliamos por morfometria o colágeno nas duas metades da camada média da aorta; sua quantidade foi menor na metade externa, onde as dissecções ocorrem / In dissections and non-inflammatory aneurysms of the ascending aorta there is an increase in mucoid (proteoglycan) deposition. We analyzed by immunoperoxidase the distribution of stromelysin (MMP-7), matrilysin (MMP-3) and plasminogen/plasmin, enzymes that act on proteoglycans, in sections of human aortas with these diseases and in controls. In cases with any of these diseases MMP-7 and MMP-3 were accumulated in the areas of mucoid degeneration, and plasmin around them. Such enzymes could thus be involved in these diseases. We also evaluated by morphometry the amount of collagen in the two halves of the aortic media. There is less collagen at the external half, in which dissections occur...

Fibrosis Hepática: El papel de las metaloproteinasas y de TGF-β / Hepatic fibrosis: Role of matrix Metallopoteases and TGF-β

La fibrosis hepática involucra múltiples eventos celulares y moleculares que inducen un excesivo depósito de proteínas de matriz extracelular que distorsionan la arquitectura del parénquima hepático, cuya etapa final es conocida como cirrosis. El daño proviene de una variedad de causas como abuso de drogas y enfermedades virales, autoinmunes, metabólicas y colestásicas. La degradación de estas proteínas de matriz ocurre predominantemente como una consecuencia de la acción de metalopro teinasas (MMPs) que degradan sustratos colágenos y no colágenos. La degradación de la matriz en el hígado se lleva a cabo principalmente por la acción de cuatro de estas enzimas: MMP-1, MMP-2, MMP-3 y MMP-9. En el sistema fibrinolítico, las MMPs pueden ser activadas a través de un corte proteolítico por acción del activador de plasminógeno tipo urocinasa y un segundo mecanismo de activación es realizado por las mismas MMPs. La regulación para restringir la actividad puede ser a diferentes niveles; en el sistema fibrinolítico el principal regulador es el PAI- 1, molécula que bloquea la conversión de plasminógeno a plasmina y la MMP no puede ser activada. Un segundo nivel de inhibición es posible a través del TIMP, que inhibe la actividad proteolítica aun cuando las MMPs hayan sido activadas vía plasmina. Durante condiciones patológicas la sobreexpresión de estos inhibidores es dirigida por el factor de crecimiento transformante β, el cual en un padecimiento fibrótico actúa como el más importante factor adverso.

Liver fibrosis and cirrhosis involve multiple cellular and molecular events that lead to deposition of an excess of extracellular matrix proteins and increase the distortion of normal liver architecture. Etiologies include chronic viral hepatitis, alcohol abuse and drug toxicity. Degradation of these matrix proteins occurs predominantly as a result of a family of enzymes called metalloproteinases (MMPs) that specifically degrade collagenous and non collagenous substrates. Matrix degradation in the liver is due to the action of at least four of these enzymes: MMP-1, MMP-2, MMP 3 and MMP 9. In the fibrinolytic system, MMPs can be activated through proteolytic cleavage by the action of urokinase plasminogen activator; a second mechanism includes the same metalloproteinases. This activity is regulated at many levels in the fibrinolytic system. The main regulator is the PAI- 1. This molecule blocks the conversion of plasminogen into plasmin, and the MMP cannot be activated. At a second level, the inhibition is possible by binding to inhibitors called TIMP that can inhibit the proteolytic activity even when the MMPs had been previously activated by plasmin. During abnormal conditions, overexpression of these inhibitors is directed by the transforming growth factor-β that in a fibrotic disease acts as an extremely important adverse factor.

Analysis of five streptokinase formulations using the euglobulin lysis test and the plasminogen activation assay

Streptokinase, a 47-kDa protein isolated and secreted by most group A, C and G ß-hemolytic streptococci, interacts with and activates human protein plasminogen to form an active complex capable of converting other plasminogen molecules to plasmin. Our objective was to compare five streptokinase formulations commercially available in Brazil in terms of their activity in the in vitro tests of euglobulin clot formation and of the hydrolysis of the plasmin-specific substrate S-2251Õ. Euglobulin lysis time was determined using a 96-well microtiter plate. Initially, human thrombin (10 IU/ml) and streptokinase were placed in individual wells, clot formation was initiated by the addition of plasma euglobulin, and turbidity was measured at 340 nm every 30 s. In the second assay, plasminogen activation was measured using the plasmin-specific substrate S-2251Õ. StreptaseÕ was used as the reference formulation because it presented the strongest fibrinolytic activity in the euglobulin lysis test. The UnitinaseÕ and SolustrepÕ formulations were the weakest, showing about 50 percent activity compared to the reference formulation. All streptokinases tested activated plasminogen but significant differences were observed. In terms of total S-2251Õ activity per vial, StreptaseÕ (75.7 ± 5.0 units) and StreptonaseÕ (94.7 ± 4.6 units) had the highest activity, while UnitinaseÕ (31.0 ± 2.4 units) and StrekÕ (32.9 ± 3.3 units) had the weakest activity. SolustrepÕ (53.3 ± 2.7 units) presented intermediate activity. The variations among the different formulations for both euglobulin lysis test and chromogenic substrate hydrolysis correlated with the SDS-PAGE densitometric results for the amount of 47-kDa protein. These data show that the commercially available clinical streptokinase formulations vary significantly in their in vitro activity. Whether these differences have clinical implications needs to be investigated.

Extraction of plasminogen activator in the rat's submaxillary gland

El objetivo de este estudio fue extraer y cuantificar el activador de plasminógeno AP en glándulas salivares de la rata. AP se extrajo por homogeneización de 1 vol de tejido com 1 vol de una solución de 2M KSCN. La solución con AP fue pipeteada por triplicado en placas de fibrina PF ricas y pobres en plasminógeno. La actividad fibrinolítica inducida por AP se observó como áreas circulares de licuefacción medidas en mm2, resultado del producto de dos diámetros perpendiculares de las zonas de lisis. El AP de la submaxilar produjo un término medio de actividad lítica de 198 mm2 + ou - 18ESM únicamente en PF ricas en plasminógeno. Extrapolando al área de lisis producida por 50 mg/ml de plasmina. No se observó lisis con AP extraído de la parótida y sublingual. La droga antifibrinolítica E-ACA, redujo significantemente, en una acción inhibitoria, dosis dependiente, la actividad fibrinolítica del AP de la submaxilar. El hecho de que AP indujo lisis únicamente en PF ricas en plasminógeno, la que fue significativamente reducida por E-ACA, indica claramente que la actividad lítica observada en el sustrato fibrina es debido a una fibrinolisis específica y no debido a una proteólisis no específica

Trombosis venosa profunda de miembros inferiores : tratamiento farmacológico / Deep venous thrombosis of lower extremities : pharmacology treatment

La trombosis venosa profunda aguda puede presentar dos secuelas graves: la embolia pulmonar en la primera etapa y el síndrome postrombótico como complicación tardía. Es por lo tanto comprensible que la primera preocupación sea la implementación de una terapia activa como la trombolisis. Es necesario reabrir la oclusión en pocos días. Ello es posible sólo mediante la adición de factores exógenos tales como la Estreptoquinasa, la Uroquinasa y el TPA. Dosis altas de heparina se usan para reducir notoriamente la incidencia de embolia pulmonar. El tratamiento de mantenimiento se realiza con anticoagulantes orales como los cumarínicos y la Warfarina.

Sistema fibrinolítico / Fibrinolytic system

Se describen algunas de las características bioquímicas más relevantes de las proteinas que intervienen en el sistema fibrinolítico, así como los más importantes mecanismos de acción de los activadores e inhibidores del plasminógeno. Se exponen de forma breve, los mecanismos que tienen lugar para la disolución del coágulo de fibrina y la regulación y control de este sistema