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Background: Severe yellow fever infection (YFI) may be complicated by a hemorrhagic diathesis. However, the hemostasis profile of YFI has rarely been reported. Objectives: The aim of this study was to characterize the hemostatic features of YFI by using a rotational thromboelastometry (ROTEM). Methods: We evaluated clinical, laboratory, and ROTEM parameters in adults with severe YFI and their correlation with hemostatic variables according to bleeding and death. Results: A total of 35 patients were included (median age, 49 years). ROTEM was performed in 22 patients, of whom 21 (96%) presented bleeding and 4 (18%) died. All patients who died had major bleeding. Patients who died presented prolonged clotting time (CT; median, 2326 seconds; IQR, 1898-2986 seconds) and reduced alpha angle (median, 12°; IQR, 12°-15°) in comparison with patients who had minor (median CT, 644 seconds; IQR, 552-845 seconds and alpha angle, 47°; IQR, 28°-65°) and major (median CT, 719 seconds; IQR, 368-1114 seconds and alpha angle, 43°; IQR, 32°-64°) bleeding who survived. In patients who had bleeding, CT showed a strong negative correlation with factor (F)V (r = -.68), FIX (r = -.84), and FX (r = -.63) as well as alpha angle showed a strong negative correlation with FIX (r = -.92). In patients who died, the correlations were even stronger. A total of 19/21 (90%) patients presented hypocoagulability assessed by ROTEM. Conclusion: Hypocoagulabitity is the hallmark of the bleeding diathesis of severe YFI. Abnormal CT and alpha angle associated with death and could be used as potential predictors of adverse outcome in severe YFI.
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Yellow fever (YF) is an acute tropical infectious disease caused by an arbovirus and can manifest as a classic hemorrhagic fever. The mechanism of the bleeding diathesis in YF is not well understood. We assessed clinical and laboratory data (including a panel of coagulation tests) from 46 patients with moderate (M) and severe (S) YF admitted to a local hospital between January 2018 and April 2018. Among 46 patients, 34 had SYF of whom 12 (35%) patients died. A total of 21 (45%) patients developed some type of bleeding manifestation and 15 (32%) presented severe bleeding. Patients with SYF had more severe thrombocytopenia (p = 0.001); prolonged activated partial thromboplastin time (aPTT) and thrombin time (TT) (p = 0.03 and p = 0.005, respectively); reduced plasma levels of coagulation factor (F) II (p < 0.01), FIX (p = 0.01), and FX (p = 0.04); and D-dimer levels almost 10 times higher (p < 0.01) when compared with patients with MYF. Patients who died had more bleeding (p = 0.03), more major bleeding (p = 0.03), prolonged international normalized ratio (INR) and aPTT (p = 0.003 and p = 0.002, respectively), as well as lower activity of FII (p = 0.02), FV (p = 0.001), FVII (p = 0.005), FIX (p = 0.01), and protein C (p = 0.01) than the ones who survived. FVIII levels were either normal or increased in all patients studied. Our results suggest that the bleeding diathesis of SYF is associated with the deficiency of coagulation factors produced by the liver. Prolonged INR and aPTT and reduced FII, FV, FVII, FIX, and protein C were associated with death.
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Transtornos da Coagulação Sanguínea , Febre Amarela , Humanos , Proteína C , Suscetibilidade a Doenças , Fatores de Coagulação Sanguínea/metabolismo , Testes de Coagulação Sanguínea/métodosRESUMO
Poor management of either type 1 diabetes or haemophilia A can lead to complications such as organ dysfunction and haemarthropathy. Here, we describe the case of an 8-year-old boy diagnosed with severe haemophilia A shortly after birth. At 2 years old, he was also diagnosed with type 1 diabetes. After six years, the haemophilia treatment was changed from a plasma-derived factor VIII (FVIII) concentrate (octanate®, Octapharma, Lachen, Switzerland) to Nuwiq® (simocotocog alfa, Octapharma, Lachen, Switzerland), a recombinant FVIII (rFVIII) product from a human cell line, which allowed for a personalised treatment schedule that supported good adherence. The dosing regimen could be reduced to two weekly rFVIII infusions. The patient has experienced no spontaneous bleeds since switching to rFVIII and shows no signs of joint damage after over seven years of FVIII prophylaxis. rFVIII was well tolerated, with no treatment-related adverse events observed. This case illustrates the importance of treatment personalisation for young patients and their families managing concomitant diseases.
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Bisphenol A (BPA) is a well-known endocrine disruptor with several effects on mammalian systems and has been linked to diseases, such as cancer. Bisphenol S (BPS) emerged as a likely alternative to BPA in industrial production. Despite being well studied and exhibiting BPA-like toxic capacity, many effects are still being elucidated. The blood coagulation system is well controlled in an effort to minimize blood loss. To our knowledge, no study reported actions of bisphenols in this system. The aim of this work was to evaluate the effects of bisphenols on blood coagulation. Zebrafish were used to measure bleeding time. To assess possible mechanisms, platelet-rich plasma was incubated with both bisphenols in the presence of arachidonic acid. Prothrombin time (PT) and activated partial thromboplastin time (APTT) assays were performed in the presence of BPA and BPS. Alignment of human factor VII sequence was compared to zebrafish and docking simulations performed with FVIIa and bisphenols. An extended time was observed in BPA-treated but not BPS-treated animals in bleeding time; in PT, bisphenols showed no effect. APTT was increased in the highest concentration of bisphenols, with no effects in platelet aggregation, indicating interference with factor VII. Protein alignment showed that both proteins have well conserved residues, as those being required for interaction of FVIIa-BPA and FVIIa-BPS complexes, as shown in molecular docking. Taken together, these data show BPA and BPS as capable of interfering with the coagulation process via FVIIa.
Assuntos
Compostos Benzidrílicos , Peixe-Zebra , Animais , Compostos Benzidrílicos/toxicidade , Coagulação Sanguínea , Humanos , Simulação de Acoplamento Molecular , Fenóis/toxicidadeRESUMO
BACKGROUND: The appearance of inhibitory antibodies against antihemophilic factors is one of the most serious complications related to hemophilia. OBJECTIVE: The objective of this study was to identify variables and factors related to the development of inhibitory antibodies in a group of patients undergoing antihemophilic therapy in Colombia. METHODS: A case-control study in patients with hemophilia treated in Specialized Healthcare Provider Institutions (IPS-E) in 21 cities of Colombia of any age and with a diagnosis of inhibitory antibodies against factor VIII or IX during 2016. Four controls per case paired by age and type of hemophilia were used. Sociodemographic, clinical, and pharmacological variables were identified and analyzed. RESULTS: Seventeen patients with inhibitory antibodies and 68 controls with hemophilia were identified. The mean age was 28.3 ± 17.8 years. A total of 94.1% had hemophilia A, and 88.2% of the cases and 50.0% of the controls had severe hemophilia; 47.1% of the cases and 54.4% of the controls were receiving prophylaxis with coagulation factors. Multivariate analysis showed that having severe hemophilia (OR:17.0, 95%CI:1.32-219.60) and lack of knowledge of the coagulation factor with which the patient was treated before entering the care program in the IPS-E (OR:8.9, 95%CI:1.82-43.75) were significantly associated with a higher probability of developing inhibitory antibodies. CONCLUSION AND RELEVANCE: Coagulation factors associated with the development of inhibitory antibodies were severe hemophilia and lack of knowledge of the type of factor used prior to entering the follow-up cohort.
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OBJECTIVES: Despite more than 40 years of experience performing the Bethesda assay (BA), poor intra- and interlaboratory precision remains the biggest laboratory challenge to date. METHODS: The BA procedure was modeled using stochastic simulation techniques to determine the precision of the BA up to dilutions of 1:4,096, to estimate the minimum significant relative change at various inhibitor titers, and to understand the laboratory procedural variables that could significantly affect the performance of the BA at high dilutions. RESULTS: Selecting the lowest dilution tube with a residual activity closest to 25% for calculating the reported Bethesda titer (BT), using a factor activity assay with a coefficient of variation less than or equal toâ 7.5% in the range of 15% to 50% factor activity level, performing the factor activity measurement in replicates, and minimizing pipette volumetric error resulted in the lowest imprecision in the reported BT. The factor neutralization kinetics of the inhibitor appear to have little impact on the precision of the assay if the incubation time is greater than 90 minutes. CONCLUSIONS: This in silico model will assist future laboratory efforts in standardizing the quantification of specific coagulation factor inhibitors and improving the precision of the reported results.
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Testes de Coagulação Sanguínea/normas , Simulação por Computador , Testes de Coagulação Sanguínea/métodos , Humanos , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Hemophilia B (HB) is a coagulation disorder with an X-linked recessive inheritance pattern, caused by plasma FIX deficiency. In Colombia, HB is considered a rare and high-cost disease, with 362 males reported in 2017. METHODS: Here, we characterized 20 HB apparently unrelated families by PCR amplification and Sanger sequencing. RESULTS: Fourteen unique variants were identified: seven missense, three nonsense, one variant in the 3' UTR region, two large deletions >50 bp, and one intronic substitution that affects splicing c.520+13A>G that was present in 7/20 patients (35%). All these variants have been previously reported in the literature, except for exons 3 and 4, deletions, present in one patient. The genotype-phenotype association correlates with the reported in the literature, with the exception of one patient. CONCLUSION: This molecular analysis allowed us to establish the causal variant of HB in 100% of patients, to provide the appropriate genetic counseling to each of the families, and to propose a more cost-effective carrier analysis. Here, we reported the first variants in Colombian population with Hemophilia B, finding a new variant and one intron recurrent variant present in 35% of patients.
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Fator IX/genética , Hemofilia B/genética , Mutação , Adolescente , Adulto , Idoso , Criança , Colômbia , Frequência do Gene , Humanos , Masculino , Pessoa de Meia-Idade , FenótipoRESUMO
ABSTRACT In patients with autoimmune diseases, the simultaneous occurrence of lupus anticoagulant and blood coagulation factors inhibitors is infrequent and is associated with hemorrhagic events. In these cases, the initial approach requires a thorough interpretation of coagulation laboratory tests and mixing studies to reach a definitive diagnosis. We report the case of a patient with systemic lupus erythematosus and Sjögren's syndrome who presented with hemorrhagic diathesis caused by circulating inhibitors against factors VIII and XI coexisting with lupus anticoagulant. The inhibitors eradication was made with rituximab, achieving good results.
RESUMEN La ocurrencia simultánea de anticoagulante lúpico e inhibidores circulantes contra los factores de la coagulación es infrecuente en los pacientes con enfermedad autoinmune, y está relacionada con eventos hemorrágicos. El abordaje inicial requiere una adecuada interpretación de los tiempos de coagulación y prueba de mezcla con plasma para alcanzar el diagnóstico definitivo. Se reporta el caso de una paciente con lupus eritematoso sistémico y síndrome de Sjögren, quien se presentó con trastorno hemorrágico amenazante de la vida ocasionado por inhibidores circulantes contra los factores VIII y XI de la coagulación en coexistencia con anticoagulante lúpico. El tratamiento de erradicación de los inhibidores se realizó con rituximab, con buenos resultados.
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Humanos , Feminino , Idoso , Coagulação Sanguínea , Hemorragia , Doenças Autoimunes , Rituximab , Lúpus Eritematoso SistêmicoRESUMO
ABSTRACT Objectives: The development of antibodies (inhibitors) against exogenous factors is the main complication in the treatment of hemophilia. Both genetic and non-genetic factors are related to inhibitor development. Among the genetic factors, the type of mutation that caused the disease is one of the most important. The objectives of the present study were to establish the prevalence of inversions in introns 1 and 22 of the factor VIII gene in patients with severe hemophilia A, correlating these with inhibitor development, and to compare the results with data from the literature. Method: Unrelated severe hemophilia A patients were analyzed for the presence of inversions in intron 1 (n = 77) and intron 22 (n = 39) by polymerase chain reaction (PCR). Detection of the inhibitor was performed by the mixing test and its quantification was performed by the Bethesda method. Results: The prevalence of inversions in introns 1 and 22 was 2.6% and 41%, respectively. No patient with inversions in intron 1 had inhibitors, whereas 26.3% of patients with inversions in intron 22 developed inhibitors. Conclusion: Due to the small number of patients with inversions in intron 1, it was not possible to perform a statistical test for the correlation with risk of inhibitor development. Inversions in intron 22 of the factor VIII gene were not associated with an increased risk of inhibitor development in the analyzed samples (p = 1).
RESUMEN Introducción: El desarrollo de anticuerpos (inhibidores) contra elfactor exógeno es la principal complicación del tratamiento de hemofilias. Tanto factores genéticos como no genéticos están relacionados con la aparición de los inhibidores. Entre los factores genéticos, el tipo de mutación que originó la enfermedad es uno de los más importantes. El objetivo de este estudio fue establecer laprevalencia de las inversiones en los intrones 1 y 22 del gen del factor VIII en pacientes con hemofilia A severa, relacionándola con el desarrollo de inhibidores, así como comparar los resultados encontrados con datos de la literatura en el mundo. Método: Pacientes con hemofilia A severa no emparentados fueron analizados cuanto a la presencia de inversión en el intrón 1 (n = 77) y de la inversión en el intrón 22 (n = 39), usando la técnica de reacción en cadena de lapolimerasa. La detección del inhibidor fue realizada por el estudio de mezclas; su cuantificación, por el método Bethesda. Resultados: La prevalencia de las inversiones en los intrones 1 y 22 fueron 2,6% y 41%, respectivamente. Ningúnpaciente con la inversión en el intrón 1 presentó inhibidores, mientras 26,3% de los pacientes con la inversión en el intrón 22 desarrollaron anticuerpos. Conclusión: El pequeno número de pacientes con inversión en el intrón 1 no permitió la aplicación de la prueba estadística para correlación con el riesgo de desarrollo de inhibidores. La inversión en el intrón 22 del gen del factor VIII no se asoció a un mayor riesgo de desarrollo de inhibidores en la muestra analizada (p = 1).
RESUMO Introdução: O desenvolvimento de anticorpos (inibidores) contra o fator exógeno é a principal complicação do tratamento de hemofilias. Tanto fatores genéticos quanto não genéticos estão relacionados com o surgimento dos inibidores. Entre os fatores genéticos, o tipo de mutação que originou a doença é um dos mais importantes. Os objetivos do presente estudo foram estabelecer a prevalência das inversões nos íntrons 1 e 22 do gene do fator VIII em pacientes com hemofilia A grave, correlacionando-a com o desenvolvimento de inibidores, bem como comparar os resultados encontrados com dados da literatura mundial. Método: Foram analisados pacientes hemofílicos A graves não aparentados quanto à presença da inversão no íntron 1 (n = 77) e da inversão no íntron 22 (n = 39), utilizando a técnica de reação em cadeia dapolimerase (PCR). A detecção do inibidor foi realizada pelo teste de mistura; a sua quantificação, pelo método de Bethesda. Resultados: As prevalências das inversões nos íntrons 1 e 22 foram de 2,6% e 41%, respectivamente. Nenhum paciente com a inversão no íntron 1 apresentou inibidores, enquanto 26,3% dos pacientes com a inversão no íntron 22 desenvolveram os anticorpos. Conclusão: O número reduzido de pacientes com a inversão no íntron 1 não permitiu a aplicação de teste estatístico para a correlação com o risco de desenvolvimento de inibidores. A inversão no íntron 22 do gene do fator VIII não se associou ao maior risco de desenvolvimento de inibidores na amostra analisada (p = 1).
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The best-known inherited mild bleeding disorders (MBDs), i.e. type 1 von Willebrand disease (VWD), platelet function disorders (PFDs), and mild to moderate clotting factor deficiencies, are characterized clinically by mucocutaneous bleeding, and, although they are highly prevalent, still pose difficult diagnostic problems. These include establishing the pathological nature of bleeding, and the uncertainties surrounding the clinical relevance of laboratory results. Furthermore, the high frequency of bleeding symptoms in the normal population and the subjective appraisal of symptoms by patients or parents makes elucidating the pathological nature of bleeding difficult. Standardized bleeding assessment tools and semiquantitative bleeding scores (BSs) help to discriminate normal from abnormal bleeding. However, as most MBDs have similar bleeding patterns, for example, bleeding sites, frequency, and severity, BSs are of little help for diagnosing specific diseases. Global tests of primary hemostasis (bleeding time; PFA-100/200) lack sensitivity and, like BSs, are not disease-specific. Problems with the diagnosis of type 1 VWD and PFD include assay standardization, uncertain definition of von Willebrand factor cut-off levels, and the lack of universal diagnostic criteria for PFD. Regarding clotting factor deficiencies, the bleeding thresholds of some coagulation factors, such as factor VII and FXI, are highly variable, and may lead to misinterpretation of the clinical relevance of mild to moderate deficiencies. Remarkably, a large proportion of MBDs remain undiagnosed even after comprehensive and repeated laboratory testing. These are tentatively considered to represent bleeding of undefined cause, with clinical features indistinguishable from those of classical MBD; the pathogenesis of this is probably multifactorial, and unveiling these mechanisms should constitute a fertile source of translational research.
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Transtornos Herdados da Coagulação Sanguínea/diagnóstico , Testes de Coagulação Sanguínea , Coagulação Sanguínea/genética , Transtornos Plaquetários/diagnóstico , Testes de Função Plaquetária , Animais , Transtornos Herdados da Coagulação Sanguínea/sangue , Transtornos Herdados da Coagulação Sanguínea/genética , Transtornos Plaquetários/sangue , Transtornos Plaquetários/genética , Diagnóstico Diferencial , Predisposição Genética para Doença , Humanos , Fenótipo , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Doença de von Willebrand Tipo 1/sangue , Doença de von Willebrand Tipo 1/diagnóstico , Doença de von Willebrand Tipo 1/genéticaRESUMO
Coagulation factor VIII is one of the largest proteins attempted to be expressed in recombinant form. A very complex and labile protein which has a very short half-live and need a fast and efficient purification chain. Here, we describe a simple purification sequence using multimodal Capto MMC, affinity FVIII select and ion exchange SP-Fastflow chromatography steps without subjecting the target molecule to mechanical and temperature stress, separating impurities from rFVIII using net charge, hydrophobicity, and affinity of the molecules.
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Fator VIII/isolamento & purificação , Fígado/química , Proteínas Recombinantes/isolamento & purificação , Linhagem Celular , Cromatografia de Afinidade/métodos , Cromatografia por Troca Iônica/métodos , Meia-Vida , HumanosRESUMO
Recombinant coagulation factor VII is a very important and complex protein employed for treatment of hemophiliac patients (hemophilia A/B) who develop inhibitors antibodies to conventional treatments (FVIII and FIX). The rFVII is a glycosylated molecule and circulates in plasma as zymogen of 50 kDa. When activated the molecule is cleaved to 20-30 kDa and has a half-life of about 3 h, needing to be processed fast and efficiently until freeze-drying. Here, we describe a very simple and fast purification sequence for rFVII using affinity FVII Select resin and a dialysis system that can be easily scaled up.
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Fator VII/isolamento & purificação , Proteínas Recombinantes/isolamento & purificação , Cromatografia de Afinidade/métodos , Glicosilação , Meia-VidaRESUMO
Coagulation factor VIII (FVIII) is an important glycoprotein involved in the extrinsic coagulation cascade. Mutations in FVIII gene results in hemophilia A, a recessive coagulation disorder that is clinically managed by administration of purified FVIII from blood donors or recombinant FVIII. Because of its fundamental therapeutic application, biotechnological production of FVIII requires rigid quality control and monitoring in patients and clinical trials. Here, we describe a protocol for a mass spectrometry based approach termed selective reaction monitoring (SRM) as an important alternative tool for accurate and sensitive quantitation of purified or recombinant FVIII.
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Fator VIII/química , Glicoproteínas/química , Espectrometria de Massas/métodos , Controle de QualidadeRESUMO
Hereditary angioedema is an autosomal dominant disease characterized by recurrent angioedema attacks with the involvement of multiple organs. The disease is unknown to many health professionals and is therefore underdiagnosed. Patients who are not adequately diagnosed and treated have an estimated mortality rate ranging from 25% to 40% due to asphyxiation by laryngeal angioedema. Intestinal angioedema is another important and incapacitating presentation that may be the main or only manifestation during an attack. In this article, a group of experts from the "Associação Brasileira de Alergia e Imunologia (ASBAI)" and the "Grupo de Estudos Brasileiro em Angioedema Hereditário (GEBRAEH)" has updated the Brazilian guidelines for the diagnosis and treatment of hereditary angioedema.
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Humanos , Angioedemas Hereditários/diagnóstico , Brasil , Complemento C4/análise , Diagnóstico Diferencial , Proteína Inibidora do Complemento C1/análise , Angioedemas Hereditários/classificação , Angioedemas Hereditários/fisiopatologiaRESUMO
Snake venom toxins that activate coagulation factors are key players in the process of venom-induced coagulopathy, and account for severe clinical manifestations. The present study applies a variety of biochemical, hematological, and histopathological approaches to broadly investigate the intravascular and systemic effects of moojenactivase (MooA), the first described PIIId subclass metalloprotease isolated from Bothrops sp. venom that activates coagulation factors. MooA induced consumption coagulopathy with high toxic potency, characterized by prolongation of prothrombin and activated partial thromboplastin time, consumption of fibrinogen and the plasma coagulation factors X and II, and thrombocytopenia. MooA promoted leukocytosis and expression of the proinflammatory cytokines interleukin-6 and tumor necrosis factor-α, accompanied by tissue factor-dependent procoagulant activity in peripheral blood mononuclear cells. This metalloprotease also caused intravascular hemolysis, elevated plasma levels of creatine kinase-MB, aspartate transaminase, and urea/creatinine, and induced morphopathological alterations in erythrocytes, heart, kidney, and lungs associated with thrombosis and hemorrhage. Diagnosis of MooA-induced disseminated intravascular coagulation represents an important approach to better understand the pathophysiology of Bothrops envenomation and develop novel therapeutic strategies targeting hemostatic disturbances.
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Coagulação Sanguínea/efeitos dos fármacos , Venenos de Crotalídeos/farmacologia , Coagulação Intravascular Disseminada/induzido quimicamente , Coagulação Intravascular Disseminada/fisiopatologia , Metaloendopeptidases/farmacologia , Venenos de Serpentes/enzimologia , Animais , Biomarcadores/sangue , Coagulação Intravascular Disseminada/sangue , Coagulação Intravascular Disseminada/metabolismo , Relação Dose-Resposta a Droga , Eritrócitos/efeitos dos fármacos , Masculino , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Recombinant human factor VIII (rFVIII) is used in replacement therapy for hemophilia A. Current research efforts are focused on bioengineering rFVIII molecules to improve its secretion efficiency and stability, limiting factors for its efficient production. However, high expression yield in mammalian cells of these rFVIII variants is generally associated with limited proteolytic processing. Non-processed single-chain polypeptides constitute non-natural FVIII molecule configurations with unpredictable toxicity and/or antigenicity. Our main objective was to demonstrate the feasibility of promoting full-proteolytic processing of an rFVIII variant retaining a portion of the B-domain, converting it into the smallest natural activatable form of rFVIII, while keeping its main advantage, i.e., improved secretion efficiency. We generated and employed a CHO-DG44 cell clone producing an rFVIII variant retaining a portion of the B-domain and the FVIII native cleavage site between Arg(1648) and Glu(1649). By bioengineering CHO-DG44 cells to express stably the recombinant human endoproteases PACE, PACE-SOL, PCSK5, PCSK6, or PCKS7, we were able to achieve complete intra- or extracellular proteolytic processing of this rFVIII variant. Additionally, our quantitative data indicated that removal of the B-domain segment by intracellular proteolytic processing does not interfere with this rFVIII variant secretion efficiency. This work also provides the first direct evidence of (1) intracellular cleavage at the Arg(1648) FVIII processing site promoted by wild-type PACE and PCSK7 and (2) proteolytic processing at the Arg(1648) FVIII processing site by PCSK6.
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Fator VIII/química , Fator VIII/metabolismo , Furina/metabolismo , Animais , Células CHO , Cricetulus , Fator VIII/genética , Humanos , Pró-Proteína Convertases/metabolismo , Proteólise , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Serina Endopeptidases/metabolismo , Subtilisinas/metabolismoRESUMO
INTRODUCTION: Prothrombin time (PT) and activated partial thromboplastin time (APTT) sensitivity for detecting isolated factor deficiencies varies with different reagents and coagulometers. The Clinical and Laboratory Standards Institute (CLSI) H47A2 guideline proposed a method to calculate these sensitivities, but some inconsistency has been reported. This study aimed to calculate factor sensitivities using CLSI guideline and to compare them with those obtained from single factor-deficient patients' data. METHODS: Different mixtures of normal pooled and deficient plasmas were prepared (<1IU/dL to 100 IU/dL) according to the CLSI H47A2 guideline. PT with rabbit brain (RB) and human recombinant (HR) thromboplastins, APTT and factors' activities were measured in an ACL TOP coagulometer. Sensitivities (maximum factor concentration that produces PT or APTT values out of the reference range) were calculated from mixtures and from patients with single-factor deficiencies: 17 factor FV, 36 FVII, 19 FX, 39 FVIII, 15 FIX 15 FXI and 24 FXII. RESULTS: PT sensitivity with RB was as follows: FV 38 and 59, FVII 35 and 58, FX 56 and 64 IU/dL; PT sensitivity with HR was as follows: FV 39 and 45, FVII 51 and 50, FX 33 and 61 IU/dL; and APTT sensitivity was as follows: FV 39 and 45, FX 32 and 38, FVIII 47 and 60, FIX 35 and 44, FXI 33 and 43, FXII 37 and 46 IU/dL, respectively. CONCLUSIONS: Reagent-coagulometer combination has adequate sensitivities to factor deficiencies according to guideline recommendations (>30 IU/dL). These should not be considered as actual sensitivities because those obtained by analysing patients' plasmas with single-factor deficiencies were higher for most factors and could induce misinterpretation of the basic coagulation test results.
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Coagulação Sanguínea , Transtornos de Proteínas de Coagulação/sangue , Transtornos de Proteínas de Coagulação/diagnóstico , Tempo de Tromboplastina Parcial/normas , Tempo de Protrombina/normas , Fatores de Coagulação Sanguínea , Humanos , Guias de Prática Clínica como Assunto , Valores de Referência , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: The activated protein C (APC) resistance is the most common prothrombotic defect in thrombosis patients, mainly related with alterations in the F5 gene. In this work, we evaluated the presence of variants in the FV gene in Amerindian patients with deep venous thrombosis and APC resistance. METHODS: A total of 87 patients with deep venous thrombosis (DVT) confirmed by Doppler ultrasonography, and Amerindian genetic background, were included in this study. APC resistance was assayed by clotting methods and polymorphism F51691G>A was genotyped by molecular methods. In Amerindian patients with APC resistance, the promoter region, exon 7 and exon 10 of the F5 gene were screened by PCR-SSCP and DNA sequencing. The prediction of functional effect of novel mutations was analyzed using Polyphen-2 software. RESULTS: In DVT patients, 14.9% showed functional APC resistance in the absence of F51691G>A polymorphism. Interestingly, three novel missense mutations in exon 10 of F5 gene (M443L, E461Q and G493E) were identified. These genetic variants were absent in 100 healthy subjects. According to in silico analysis, the sequence variants G493E and E461Q are potentially deleterious. CONCLUSIONS: Our data shows that the APC resistance phenotype is not associated with the presence of the F51691G>A variant. We described, for the first time, the presence of three novel variants in F5 gene in Chilean patients with APC resistance. Further studies are required to investigate the real contribution of these novel mutations to the APC resistance phenotype.
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Etnicidade/genética , Fator V/genética , Variação Genética/genética , Indígenas Sul-Americanos/genética , Proteína C/genética , Trombose Venosa/genética , Adolescente , Adulto , Idoso , Chile , Fator V/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Trombose Venosa/sangue , Trombose Venosa/diagnóstico , Adulto JovemRESUMO
Factor VIII (FVIII) is a glycoprotein that plays an essential role in blood coagulation cascade. Purification of plasma-derived coagulation FVIII by direct application of plasma to a chromatographic column is a method of choice. Anion exchange column is a very powerful method because FVIII is strongly adsorbed, resulting in good activity recovery and high purification factor. However, vitamin-K-dependent coagulation factors coelute with FVIII. In the present study, we report the separation of vitamin-K-dependent coagulation proteins from FVIII using immobilized metal affinity chromatography (IMAC) with Cu(2+) as the metal ligand. Plasma was directly loaded to a Q Sepharose Big Beads column, and FVIII was recovered with 65% activity and a purification factor of approximately 50 times. Then, the Q Sepharose eluate was applied to the IMAC-Cu(2+) column, and FVIII was eluted with 200 mM imidazole, with up to 85% recovery of activity. The mass recovery in this fraction was less than 10% of the applied mass of protein. Vitamin-K-dependent proteins elute with imidazole concentrations of lower than 60 mM. Because of the difference in affinity, FVIII could be completely separated from the vitamin-K-dependent proteins in the IMAC column.
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Cromatografia de Afinidade/métodos , Cobre/química , Fator VIII/isolamento & purificação , Fator VIII/química , Fator VIII/metabolismo , Humanos , Modelos MolecularesRESUMO
The current state of the art in medical genetics is to identify and classify the functional (deleterious) or non-functional (neutral) single amino acid substitutions (SAPs), also known as non-synonymous SNPs (nsSNPs). The primary goal is to elucidate the mechanisms through which functional SAPs exert their effects, and ultimately interrogating this information for association with complex phenotypes. This work focuses on coagulation factors involved in the coagulation cascade pathway which plays a vital role in the maintenance of homeostasis in the human system. We developed an integrated coagulation variation database, CoagVDb, which makes use of the biological information from various public databases such as NCBI, OMIM, UniProt, PDB and SAPs (rsIDs/variant). CoagVDb enriched with computational prediction scores classify SAPs as either deleterious or tolerated. Also, various other properties are incorporated such as amino acid composition, secondary structure elements, solvent accessibility, ordered/disordered regions, conservation, and the presence of disulfide bonds. This specialized database provides integration of various prediction scores from different computational methods along with gene, protein, and disease information. We hope our database will act as a useful reference resource for hematologists to reveal protein structure-function relationship and disease genotype-phenotype correlation.