Increased expression of tissue factor and protease-activated receptor-1 does not correlate with thrombosis in human lung adenocarcinoma

A correlation between cancer and hypercoagulability has been described for more than a century. Patients with cancer are at increased risk for thrombotic complications and the clotting initiator protein, tissue factor (TF), is possibly involved in this process. Moreover, TF may promote angiogenesis and tumor growth. In addition to TF, thrombin seems to play a relevant role in tumor biology, mainly through activation of protease-activated receptor-1 (PAR-1). In the present study, we prospectively studied 39 lung adenocarcinoma patients in relation to the tumor expression levels of TF and PAR-1 and their correlation with thrombosis outcome and survival. Immunohistochemical analysis showed TF positivity in 22 patients (56 percent), most of them in advanced stages (III and IV). Expression of PAR-1 was found in 15 patients (39 percent), most of them also in advanced stages (III and IV). Remarkably, no correlation was observed between the expression of TF or PAR-1 and risk for thrombosis development. On the other hand, patients who were positive for TF or PAR-1 tended to have decreased long-term survival. We conclude that immunolocalization of either TF or PAR-1 in lung adenocarcinoma may predict a poor prognosis although lacking correlation with thrombosis outcome.

Policitemia vera: relato de caso / Polycythemia vera: case report

A policitemia vera (PV) é um transtorno mieloproliferativo das células hematopoiéticas, caracterizada poruma produção anormal e acentuada de eritrócitos, leucócitos e plaquetas. É uma doença rara, com uma incidênciade 2,3/100.000 pessoas por ano. Apresentamos um relato de caso de uma paciente de 45 anos com sintomas,sinais e achados sugestivos de policitemia vera.

The polycythemia vera is a myeloproliferative disturb from haematopoietic cells characterized by abnormal and overstated production of erythrocytes, leukocytes and platelets. It is a rare disease with an incidenceof 2.3/100.000 people per year. We present a case report of a 45 years old patient with symptoms, signs andsuggestive results of polycythemia vera.

La hiperhomocisteinemia como factor de riesgo vascular en hemodializados crónicos / Hyperhomocysteinemia as a vascular risk factor in chronic hemodialysis patients

La homocisteína es un factor de riesgo independiente de enfermedad cardiovascular en la población general, y juega un rol protagónico en el desarrollo de la aterogénesis y las trombosis vasculares, sobre todo en pacientes con insuficiencia renal. Así pues, los pacientes en hemodiálisis están bajo los efectos tóxicos de la hiperhomocisteinemia, presente en cerca del 90% de estos pacientes. En nuestra experiencia hemos encontrado que el ácido fólico es un tratamiento eficaz para disminuir los niveles de homocisteína, y el agregado de metilcobalamina intravenosa potencia este efecto; sin embargo, la metilcobalamina por sí sola fue insuficiente para normalizar la homocisteinemia. A lo largo del tiempo, un grupo de pacientes requirió dosis más elevadas de ácido fólico para corregir la hiperhomocisteinemia. Los pacientes homocigotas y, en menor medida hete-rocigotas para la variante termolábil C677T de la enzima metilentetrahidrofolato reductasa (MTHFR), presentaron una actividad catalítica reducida reflejada en la necesidad de una mayor dosis de ácido fólico para normalizar los niveles de homocisteína. Los efectos trombóticos vasculares fueron similares en todos los pacientes respecto a las variantes genéticas de la enzima metilentetrahidrofolato reductasa, sugiriendo que el tratamiento de la hiperhomocisteinemia es importante para disminuir el riesgo de trombosis. Sin embargo, también la hipoho-mocisteinemia, asociada generalmente a estados de desnutrición, se asocia a mayor mortalidad. Si bien se considera a la hiperhomocisteinemia como un factor de riesgo vascular en los pacientes con insuficiencia renal, aún no se determinó en esta población si su corrección se asocia a una disminución de la tasa de enfermedad vascular y de trombosis. No obstante...

Homocysteine is an independent risk factor for cardiovascular disease in the general population. In addition, it plays a main role in the development of atherogenesis and thrombosis, particularly in end-stage renal disease patients. Therefore, hemodialysis patients are under the burden of homocysteine toxic effects, present in nearly 90% of dialysis patients. Our group found that folic acid is an efficient therapeutic approach to decrease homocysteine levels, and the addition of intravenous methylcobalamin potentiates this effect; however, methylcobalamin alone was unsuccessful to normalize homocysteine levels. With time a group of patients required a higher dose of folic acid to reduce hyperhomocysteinemia. Patients homozygous and, to a lesser extent heterozygous, to the C677T thermolabile variant of methylenetetrahydrofolate reductase (MTHFR) presented a reduced catalytic activity and required a higher folic acid dose. Vascular-access thrombotic events were similar in all patients according to the variants of the enzyme, suggesting that treating hyperhomocysteinemia was the key to lower the risk of thromboses. Noteworthy, hypohomocysteinemia, generally acompanying malnourishment, is associated to higher mortality. Albeit hyper-homocysteinemia is considered a vascular risk factor in renal failure patients, it has not yet been established in this population if its correction is associated with a decrease in the rate of vascular disease and thrombosis. However, given the mentioned evidence about the low risk and good tolerance of vitamin therapy, we believe it useful to know folate, cobalamin and homocysteine blood levels in chronic renal patients and start a prompt treatment, which may proof adequate to maintain homocysteine levels of 10 +/- 5 micromol/l.