Lack of association between potential prothrombotic genetic risk factors and arterial and venous thrombosis.

Recent studies have shown an association between thrombosis and factor VII (FVII), tissue factor (TF), and angiotensin-converting enzyme (ACE). This suggests that individuals with FVII-402 G/A, FVII-401 G/T, TF+5466 A/G, and ACE-287 insertion/deletion (I/D) polymorphisms present an increased risk of venous thrombosis, heart disease, and ischemic stroke compared with controls. In this study, we investigated the frequencies of these polymorphisms and their association with arterial and venous thrombosis. For the FVII-402 G/A polymorphism, there were 57.3% heterozygote (HT) genotypes and 8.3% homozygote (HM) genotypes in the patients, and 45.2% HT genotypes and 15.4% HM genotypes in the controls. For the FVII-401 G/T polymorphism, there were 37.5% HT genotypes and 3.1% HM genotypes in the patients, and 32.7% HT genotypes and 4.8% HM genotypes in the controls. The polymorphism TF+5466 A/G was not found in any of the samples analyzed. For the ACE-287 I/D polymorphism, there were 43 (40.6%) HT genotypes and 63 (59.4%) HM genotypes in the controls and 28 (45.2%) HT genotypes and 34 (54.8%) HM genotypes in the patients. No significant difference was observed by comparing patients and controls. In this study, no association was found between the presence of the evaluated polymorphisms and the occurrence of thrombotic events.

Fibrinolytic system in preeclampsia.

Preeclampsia (PE) is a multi-system disorder of human pregnancy characterized by hypertension and proteinuria. Although its pathogenesis is not fully understood, predisposition to endothelial dysfunction is thought to play a crucial part. Normotensive pregnancy is associated with increases in coagulation factor levels and decreases in natural anticoagulation, leading to a hypercoagulable state. This state is thought to be part of a complex physiological adaptation, which ensures rapid and effective control of bleeding from the placental site at the time of placental separation. In PE, a more pronounced exacerbation of the hypercoagulable state is noticed, compared to normotensive pregnancy. Activation of coagulation in PE occurs at an early stage of the disease and often antedates the clinical symptoms. It is known that PE is associated with fibrin deposition in the kidney glomerulus, and in fatal cases, widespread fibrin deposition has been a prominent histological finding. Related to the fibrinolytic system in PE, the state of the art allows the assumption that blood coagulation overlaps the fibrinolytic regulatory mechanism, since fibrin deposition in maternal microcirculation is usually found in PE. However, there is still no consensus about its specific role. This review aims to discuss the fibrinolytic system in PE and its potential implications to the pathogenesis of this disease.

D-dimer as a possible prognostic marker of operable hormone receptor-negative breast cancer.

BACKGROUND: Breast cancer is the most common cause of death in women by neoplasia. The mechanisms related to recurrence are unclear, specially the hemostatic alterations that occur during the development of the disease. Plasma D-dimer is a hypercoagulability and fibrinolytic system marker and is increased in patients with various solid tumors. The purpose of this study was to evaluate the hemostatic status assessed by plasma D-dimer in operable breast cancer patients and to investigate its value as a prognostic marker. MATERIALS AND METHODS: The study comprised 32 patients with operable hormone receptor-negative breast cancer and a control group with 43 healthy women. Variables included presence and absence of breast cancer, clinical and histopathology findings, and overall survival. RESULTS: Plasma D-dimer level was normal in the control group and significantly higher in breast cancer patients (P = 0.001), as well as in nonsurvivors compared with survivors (P = 0.025). The results showed that plasma D-dimer levels were not correlated with clinical and histopathology findings (P > 0.213). CONCLUSIONS: The results taken together indicate the presence of a hypercoagulability state in women with operable hormone receptor-negative breast cancer given the increased levels of D-dimer in this group. Therefore, considering higher levels of D-dimer in patients with a poor outcome, its evaluation may be a promising tool for prognosis in women with operable hormone receptor-negative breast cancer.

Intracellular nitric oxide assessment in whole blood leukocytes by flow cytometry: optimization and applicability to monitor patients with chronic graft nephropathy.

Flow cytometry has been proposed as an alternative method for direct determination of intracellular NO by using the 4,5-diaminofluorescein-diacetate (DAF-2DA) as a fluorescent probe. In the present study, the protocol for intracellular NO determination in peripheral blood monocytes and neutrophils of by flow cytometry was optimized and applied to monitor chronic graft nephropathy patients. The optimize method consists to incubate plasma-free whole blood samples with DAF-2DA at 2.0 microM for 180 min at 37 degrees C to determine the percentage of DAF-2T+ monocytes and neutrophils. Distinct intracellular NO profiles in monocytes and neutrophils from chronic graft nephropathy patients as compared to the healthy individuals. Although the pre-incubation with LPS was able to trigger higher percentages of DAF-2T+ monocytes and neutrophils in both groups, our data demonstrated that LPS had a greater impact on monocytes as compared to neutrophils, selectively in the group of healthy individuals. Moreover, our findings demonstrated that LPS had lower impact on monocytes from chronic graft nephropathy as compared to healthy individuals. Supplementary analysis revealed that the LPS impact tends to be resorted in those patients with longer post-transplant time, as demonstrated by a significant positive correlation index. Furthermore, our results demonstrated that AG had lower inhibitory impact on neutrophils as compared to monocytes, selectively in the group of chronic graft nephropathy patients. Taken together, this study showed a new approach to monitor the immunological status of patients with chronic graft nephropathy opening new perspectives of research regarding the monocyte and neutrophil functions in patient undergoing immunosuppressive therapy.

Evaluation of the blood coagulation mechanism and platelet aggregation in individuals with mechanical or biological heart prostheses.

Oral anticoagulants have been widely employed to decrease thrombotic risk by reducing the levels of vitamin K-dependent clotting factors. Paradoxically, the use of oral anticoagulants also decreases the levels of natural anticoagulants (protein C and protein S), which favors the hypercoagulability state. Increased platelet activation has been reported in patients undergoing warfarin treatment. These findings have raised questions about the antagonistic effect of oral anticoagulants and their implications for hemostatic balance. The aim of this study is to determine the relationship between warfarin dosage and prothrombin time [International Normalized Ratio (INR)], platelet aggregation, vitamin K-dependent clotting factors, and protein C and protein S. Blood samples from 27 patients were analyzed, seven with mechanical prostheses and 20 with biological prostheses, and 27 controls. Multiple regression analysis showed that factor II most significantly determines the INR. Results showed that the INR, clotting factors, and protein C and protein S activity did not correlate with warfarin dosage, highlighting the need for accurate laboratory monitoring of those undergoing anticoagulant therapy.

Avaliaçäo dos vasos, da agregaçäo plaquetária e do mecanismo da anticoagulaçäo natural nas doenças coronarianas / Vessels, platelet aggregation and natural anticoagulation mechanism evaluations in coronarian diseases

Este trabalho teve como objetivo investigar a presença de lesäo e seu efeito sobre a competência funcional do mecanismo da anticoagulaçäo natural. Foram analizadas 45 amostras de sangue de pacientes com angina de peito (n=11), indivíduos com alto risco para desenvolverem essas doenças, porém, assintomáticos (n=16) e de indivíduos sadios empregados como controle (n=10). Foram realizadas a avaliaçäo de trombomodulina (marcador de lesäo endotelial), da agregaçäo plaquetária, do fibrinogênio, do fator VIII e da proteína C, essa envolvida no sistema da anticoagulaçäo natural. Os níveis de trombomodulina, fator VIII e fibrinogênio se mostraram elevados nos pacientes com infarto e angina, ao contrário da proteína C, que se mostrou diminuída nesses pacientes, quando comparados ao controle. Diferenças entre os grupos controle e de risco foram observadas apenas para o teste da agregaçäo plaquetária, cujos resultados foram similares para os grupos de risco, angina e infarto, sugerindo que este teste pode ser utilizado como um parâmetro preditivo de risco para doença coronariana. Uma interpretaçäo dos resultados permite estabelecer a ocorrência de lesäo endotelial e sua consequência sobre a competência funcional do sistema da anticoagulaçäo em pacientes com tais doenças, resultando em um desequilíbrio entre procoagulantes e anticoagulantes, o que favorece a formaçäo de trombo.

Estudo comparativo de métodos analíticos para dosagem de metemoglobina no sangue / Comparative study among analitycal methods to blood methemoglobin determination

A exposição ocupacional aos solventes anilina e nitrobenzeno é monitorizada biologicamente através da determinação dos níveis de metemoglobina sanguínea. O máximo teor de metemoglobina permitido nas amostras de sangue dos indivíduos expostos é 5% da hemoglobina total, obrigando a utilização de métodos analítico-sensíveis e precisos. Dois métodos analíticos utilizados na determinação de metemoglobinemia (Hegesh et all. e Evely & Malloy. Mod. Beutler), rotineiramente utilizados nos laboratórios de hematologia e Toxicologia da Faculdade de Farmácia da UFMG, foram estudados objetivando estabelecer o mais adequado para ser utilizado na monotirazação biológica de indivíduos expostos ocupacionalmente à anilina ou nitrobenzeno. Apenas o método de Hegesh et all. mostrou-se adequado para os objetivos propostos. Foram detectados valores tão baixos quanto 0,9% de metemoglobina e os coeficientes de variação intra e interensaio foram, respectivamente, 3,87% e 3,25%.