Evaluation of seven rapid tests for syphilis available in Brazil using defibrinated plasma panels.

OBJECTIVES: In 2012, the WHO estimated that 6 million new cases of syphilis per year would occur worldwide, including 937 000 in Brazil. Early diagnosis and treatment of syphilis are essential to reduce morbidity and prevent transmission. The availability of rapid tests (RTs) for this diagnosis means that testing can be performed more quickly, as a point-of-care test, even in non-laboratory environments and requires only simple technical training to antibodies detection. The objective of this study was to evaluate the performance and operational aspects of seven commercially available RTs for syphilis in Brazil. METHODS: Seven rapid treponemal tests were evaluated for sensitivity, specificity, accuracy and Kappa value, according to a panel composed of 493 members. The operational performance of the assay was also determined for these tests. RESULTS: The seven RTs showed sensitivity ranging from 94.5% to 100% when compared with the reference tests and specificity of between 91.5% and 100%. All the RTs evaluated presented good operational performance, and only one failed to present the minimum specificity as defined by Brazil's Ministry of Health. CONCLUSION: All the tests presented good operational performance, and the professionals who performed them considered them to be easy to use and interpret. This evaluation is important for making informed choices of tests to be used in the Brazilian Unified Health System.

Transient desialylation in combination with a novel antithrombin deficiency causing a severe and recurrent thrombosis despite anticoagulation therapy.

An in-depth focused study of specific cases of patients with recurrent thrombosis may help to identify novel circumstances, genetic and acquired factors contributing to the development of this disorder. The aim of this study was to carry out a detailed and sequential analysis of samples from a patient suffering from early and recurrent venous and arterial thrombosis. We performed thrombophilic tests, biochemical, functional, genetic and glycomic analysis of antithrombin and other plasma proteins. The patient carried a new type I antithrombin mutation (p.Ile218del), whose structural relevance was verified in a recombinant model. Experiments with N-glycosidase F and neuraminidase suggested a nearly full desialylation of plasma proteins, which was confirmed by mass spectrometry analysis of transferrin glycoforms. However, partial desialylation and normal patterns were detected in samples collected at other time-points. Desialylation was noticeable after arterial events and was associated with low antithrombin activity, reduced platelet count and glomerular filtration rate. This is the first description of a global and transient desialylation of plasma proteins associated with thrombosis. The decrease in the strong electronegative charge of terminal glycans may modulate hemostatic protein-protein interactions, which in combination with a strong prothrombotic situation, such as antithrombin deficiency, could increase the risk of thrombosis.

Fibrin(ogen) drives repair after acetaminophen-induced liver injury via leukocyte αMß2 integrin-dependent upregulation of Mmp12.

BACKGROUND & AIMS: Acetaminophen (APAP)-induced liver injury is coupled with activation of the blood coagulation cascade and fibrin(ogen) accumulation within APAP-injured livers of experimental mice. We sought to define the role of fibrin(ogen) deposition in APAP-induced liver injury and repair. METHODS: Wild-type, fibrinogen-deficient mice, mutant mice with fibrin(ogen) incapable of binding leukocyte αMß2 integrin (Fibγ390-396A mice) and matrix metalloproteinase 12 (Mmp12)-deficient mice were fasted, injected with 300mg/kg APAP i.p. and evaluated at a range of time-points. Plasma and liver tissue were analyzed. Rescue of Fibγ390-396A mice was carried out with exogenous Mmp12. To examine the effect of the allosteric leukocyte integrin αMß2 activator leukadherin-1 (LA-1), APAP-treated mice were injected with LA-1. RESULTS: In wild-type mice, APAP overdose increased intrahepatic levels of high molecular weight cross-linked fibrin(ogen). Anticoagulation reduced early APAP hepatotoxicity (6h), but increased hepatic injury at 24h, implying a protective role for coagulation at the onset of repair. Complete fibrin(ogen) deficiency delayed liver repair after APAP overdose, evidenced by a reduction of proliferating hepatocytes (24h) and unresolved hepatocellular necrosis (48 and 72h). Fibγ390-396A mice had decreased hepatocyte proliferation and increased multiple indices of liver injury, suggesting a mechanism related to fibrin(ogen)-leukocyte interaction. Induction of Mmp12, was dramatically reduced in APAP-treated Fibγ390-396A mice. Mice lacking Mmp12 displayed exacerbated APAP-induced liver injury, resembling Fibγ390-396A mice. In contrast, administration of LA-1 enhanced hepatic Mmp12 mRNA and reduced necrosis in APAP-treated mice. Further, administration of recombinant Mmp12 protein to APAP-treated Fibγ390-396A mice restored hepatocyte proliferation. CONCLUSIONS: These studies highlight a novel pathway of liver repair after APAP overdose, mediated by fibrin(ogen)-αMß2 integrin engagement, and demonstrate a protective role of Mmp12 expression after APAP overdose. LAY SUMMARY: Acetaminophen overdose leads to activation of coagulation cascade and deposition of high molecular weight cross-linked fibrin(ogen) species in the liver. Fibrin(ogen) is required for stimulating liver repair after acetaminophen overdose. The mechanism whereby fibrin(ogen) drives liver repair after acetaminophen overdose requires engagement of leukocyte αMß2 integrin and subsequent induction of matrix metalloproteinase 12.

A small deletion in SERPINC1 causes type I antithrombin deficiency by promoting endoplasmic reticulum stress.

Antithrombin (AT) deficiency is an autosomal dominant disorder, and identification of mutation AT variants would improve our understanding of the anticoagulant function of this serine protease inhibitor (SERPIN) and the molecular pathways underlying this disorder. In the present study, we performed whole-exome sequencing of a Chinese family with deep vein thrombosis, and identified a new small deletion that eliminates four amino acids (INEL) from exon 4 of SERPINC1 gene. This causes type I AT deficiency by enhancing the intracellular retention of this protein. AT retention leads to endoplasmic reticulum (ER) stress, which further inhibits AT release. In addition, ER stress activates ER-associated degradation, which promotes AT degradation. Suppression of ER stress enhanced the secretion of AT, while inhibition of ER-associated degradation suppressed AT release. Thus, our study identified a new mutation (INEL deletion) causing type I AT deficiency, and uncovered a novel mechanism for AT retention through enhanced ER stress, which may provide an innovative approach for treating AT deficiency.

Antithrombin deficiency in pregnancy.

We present a case of a 39-year-old, gravida 3 para 2, Chinese female with a history of inherited type 1 Antithrombin deficiency and multiple prior episodes of venous thromboembolism. She presented at 29+4 weeks' gestation with severe pre-eclampsia complicated by haemolysis, elevated liver enzymes and low platelet (HELLP) syndrome. She subsequently underwent an emergency caesarean section for non-reassuring fetal status, which was complicated by postpartum haemorrhage secondary to uterine atony, requiring a B-Lynch suture intraoperatively.

Cerebral venous sinus thrombosis in the patient with multiple sclerosis associated with congenital antithrombin deficiency.

We report the case of a 25-year-old man with multiple sclerosis (MS) who had severe headache and unconsciousness. He suffered from optic neuritis that had started at age 6. From the age of 12 years, he had suffered from multiple sclerosis (MS) cerebral lesions that relapsed three times over for 5 years. At age 25, he showed a new lesion in the cerebellar cortex, suggesting an exacerbation of the MS. However, magnetic resonance imaging findings the next day showed cerebral venous sinus thrombosis. His laboratory findings showed low antithrombin activity. Genetic analysis revealed a single-base substitution (C>T) at the codon 359 (Arg to STOP) in the 5th exon portion of the antithrombin gene, heterozygote. In the literature review, 17 cases of multiple sclerosis associated with cerebral venous sinus thrombosis, which occurred after the lumbar puncture and the treatment with high-dose methylpredonisolone in 11 of these cases. In our case, antithrombin deficiency, hyperhomocystinemia, infection, and lumbar puncture were suggested as the risk factors.

Antithrombin Katowice: exon 1 deletion in the SERPINC1 gene associated with type I antithrombin deficiency.

Type I antithrombin deficiency is an autosomal dominant disorder associated with thromboembolic complications mainly related to single-point mutations in SERPINC1, the gene encoding antithrombin. Chromosomal rearrangements have been found in up to 10% of cases with type I antithrombin deficiency. We report here the first heterozygous deletion of SERPINC1 exon 1 identified in a 44-year-old man with type I deficiency who developed deep vein thrombosis of the left leg complicated by pulmonary embolism. This study demonstrates that the search for large gene rearrangements in SERPINC1 can be a useful diagnostic approach, particularly in patients with type I antithrombin deficiency without mutations in SERPINC1.

Recurrent ischemic cerebrovascular events in a patient with type I antithrombin deficiency caused by 9788 G>A splice site mutation: a case report.

Type I antithrombin deficiency is an autosomal dominant disorder associated with high risk for venous thromboembolism. Data on the association between antithrombin deficiency and arterial thromboembolism are inconsistent. We report here the case of AT deficiency in a 43-year-old man free of cardiovascular risk factors who experienced venous thromboembolism and ischemic stroke followed by two transient ischemic attacks after interruption of oral anticoagulation due to colonoscopy. DNA sequencing of the antithrombin gene revealed heterozygosity for the previously reported substitution G to A at nucleotide position 9788 in intervening sequence four. To our knowledge, this report is the first to show that this genetic abnormality can be associated with recurrent cerebrovascular ischemic events.

Enfermedad cerebrovascular en la infancia. Análisis retrospectivo de los ingresos hospitalarios en los últimos diez años en un hospital terciario de la Comunidad Valenciana / Cerebrovascular disease in childhood: a retrospective analysis of hospital admissions in a tertiary hospital in the community of Valencia in the last ten years

Introducción: En los últimos años ha aumentado el interés por el ictus en la infancia. La revisión de la literatura aporta poca información sobre factores de riesgo y otros aspectos de interés clínico. El objetivo es describir las características del ictus en niños con el objetivo de identificar factores de riesgo, presentación clínica y el pronóstico. Pacientes y métodos: Se llevó a cabo un estudio retrospectivo entre los pacientes ingresados en el hospital La Fe entre enero de 2000 y septiembre de 2010 con los diagnósticos de ictus, isquémicos o hemorrágicos. Resultados: Un total de 76 pacientes cumplían los criterios de inclusión, 44,7% presentaron un ictus isquémico y 55,3% fue hemorrágico. La edad media de presentación fue de 6,8 años, 8,4 años para los hemorrágicos y 4,7 años para los isquémicos. La cefalea fue el síntoma de presentación más frecuente. El principal factor de riesgo fue la malformación vascular en los ictus hemorrágicos y las vasculopatías y cardiopatías en los isquémicos. En 34 pacientes se llevó a cabo un estudio de trombofilia y en un 64,7%, de estos, el estudio fue positivo. Respecto al pronóstico, el 17% de los pacientes falleció, solamente tres pacientes presentaron una epilepsia secundaria y el 31 y 60% de los infartos hemorrágicos e isquémicos, respectivamente, desarrollaron una hemiparesia. Conclusiones: En este estudio hemos identificado los principales factores de riesgo, así como edad de presentación, sintomatología y pronóstico. Queremos destacar la edad de presentación más precoz en los ictus isquémicos frente a los hemorrágicos(AU)

Introduction: There has been increasing interest in stroke in children in the last few years. A literature review produced little information on risk factors and other clinical questions. The aim of this study is to describe the characteristics of stroke in children, mainly in order to identify the risk factors, clinical presentation and outcomes. Patients and methods: A retrospective study was conducted on patients admitted to the Hospital La Fe in Valencia between January 2000 to September 2010 with the diagnosis of ischaemic or haemorrhagic stroke. Results: A total of 76 patients were identified, of whom 44.7% had an ischaemic stroke and 55.3% had a haemorrhagic one. The average age of presentation was 6.8 years; 8.4 years for haemorrhagic strokes and 4.7 years for ischaemic strokes. Headache was the most frequent symptom of presentation. The most frequent risk factor was vascular malformations in haemorrhagic cerebral stroke, and vascular and cardiac disorders in ischaemic stroke. A study of prothrombotic factors was conducted on 34 patients, which was positive in 64.7% of them. As regards outcome, 17% of the patients died; only 3 patients had a secondary epilepsy, and 31% and 60% of the haemorrhagic and ischaemic stokes, respectively, had a hemiparesis. Conclusions: In this study we identified the principal risk factors as well as, the age of presentation, symptomatology and outcome. We would like to emphasise that the age of presentation was earlier in ischaemic strokes than in haemorrhagic ones(AU)

Antithrombin Krakow II (c.624+1 G > T): a novel mutation leading to type 1 antithrombin deficiency.

Hereditary antithrombin (AT) deficiency is a rare autosomal disease. More than 200 mutations have been described in the AT gene leading to its deficiency. We describe here a case of type I AT deficiency in a 26-year-old Polish man who experienced proximal deep vein thrombosis and pulmonary embolism associated with a transient thrombotic risk factor, the right ankle trauma, despite the use of low-molecular-weight heparin prophylaxis. The family history was negative for venous thromboembolism. The AT activity was initially 47% and on repeated analysis 53%, and the antigen level, 0.15 g/l. The analysis of AT gene revealed the presence at the heterozygous state of a substitution G more than T located at the first nucleotide 3' of exon 3a (c.624 + 1 G > T, Human Genome Variation Society numbering system). The substitution might be detrimental taking account for its position in a donor splice site. To the best of our knowledge this mutation has not been previously described, so it was named antithrombin Krakow II.

Uso de fibrinógeno humano en la generación de soportes para la obtención de equivalentes tisulares / Use of human fibrinogen in the generation of scaffold for obtaining Tissue equivalents

Desde sus orígenes, la Ingeniería de Tejidos ha buscado diversos materiales que puedan ser utilizados para la generación de soportes que sirvan para el anclaje, proliferación y diferenciación celular que conduzcan a la obtención de tejidos humanos. Muchos materiales de tipo cerámico, polimérico y metálico se han evaluado, pero hasta la fecha muchos de ellos han sido rechazados por diversas razones, entre otras su escasa biocompatibilidad y biodegradabilidad, la respuesta inmune generada, la baja resistencia mecánica o el riesgo de transmisión de virus o priones. El fibrinógeno es una proteína presente en el plasma sanguíneo que puede ser utilizada para la generación de soportes tridimensionales que favorezcan el crecimiento de células; se obtiene a partir del propio paciente, bancos de sangre o como proteína purificada (Tisseel® o Tissucol®, Laboratorios Baxter). El fibrinógeno evita el desencadenamiento de una respuesta inmunológica y el uso de productos xenogénicos. Debido a la estructura proteica, la adhesión y proliferación celular se ven favorecidas dando excelentes resultados en la generación de equivalentes de piel, cartílago, córnea y reemplazos cardiacos en aplicaciones in vitro e in vivo. Como desventajas presenta su rápida degradación y su baja resistencia mecánica; sin embargo, en los últimos años se han venido evaluando mezclas con algunos biopolímeros como ácido poliláctico (PLLA), ácido poli-glicólico (PGA) y alginato de sodio. Esta revisión presenta algunas de las principales aplicaciones del fibrinógeno en Ingeniería de Tejidos.

Since its origin, Tissue Engineering has sought various materials that can be used for generation of scaffolds that serve to anchor, proliferation and cell differentiation leading to the production of human tissues. Many materials such as ceramic, polymeric and metal type have been evaluated to date but many have been rejected for various reasons, including its limited biocompatibility and biodegradability, immune response generated, low mechanical strength or the risk of transmission of virus or prions. Fibrinogen is a protein present in blood plasma that can be used to generate three-dimensional scaffolds that favors growth of cells, it is obtained from the patient itself, bank of blood or purified protein (Tisseel® or Tissucol®, Laboratorios Baxter). Fibrinogen acts slowing or reversing the immune response and avoiding the use of xenogeneic materials. Because the protein structure, adhesion and cell proliferation is favored with excellent results in the generation of skin equivalents, cartilage, cornea and even heart replacements in vitro and in vivo. The disadvantages presented are the rapid degradation and low mechanical strength, but in recent years it has been evaluating some biopolymer mixtures as polylactic acid (PLLA), poly-glycolic acid (PGA) and sodium alginate. This review presents some of the main applications of fibrinogen in Tissue Engineering.

Fibrinogen deficiency increases liver injury and early growth response-1 (Egr-1) expression in a model of chronic xenobiotic-induced cholestasis.

Chronic cholestatic liver injury induced by cholestasis in rodents is associated with hepatic fibrin deposition, and we found evidence of fibrin deposition in livers of patients with cholestasis. Key components of the fibrinolytic pathway modulate cholestatic liver injury by regulating activation of hepatocyte growth factor. However, the exact role of hepatic fibrin deposition in chronic cholestasis is not known. We tested the hypothesis that fibrinogen (Fbg) deficiency worsens liver injury induced by cholestasis. Fbg-deficient mice (Fbgα(-/-) mice) and heterozygous control mice (Fbgα(+/-) mice) were fed either the control diet or a diet containing 0.025% α-naphthylisothiocyanate (ANIT), which selectively injures bile duct epithelial cells in the liver, for 2 weeks. Hepatic fibrin and collagen deposits were evident in livers of heterozygous control mice fed the ANIT diet. Complete Fbg deficiency was associated with elevated serum bile acids, periportal necrosis, and increased serum alanine aminotransferase activity in mice fed the ANIT diet. Fbg deficiency was associated with enhanced hepatic expression of the transcription factor early growth response-1 (Egr-1) and enhanced induction of genes encoding the Egr-1-regulated proinflammatory chemokines monocyte chemotactic protein-1, KC growth-regulated protein, and macrophage inflammatory protein-2. Interestingly, peribiliary collagen deposition was not evident near necrotic areas in Fbg-deficient mice. The results suggest that in this model of chronic cholestasis, fibrin constrains the release of bile constituents from injured intrahepatic bile ducts, thereby limiting the progression of hepatic inflammation and hepatocellular injury.

[Molecular mechanisms of recurrent venous thrombosis in two pedigrees with type I antithrombin deficiency].

OBJECTIVE: To investigate the clinical phenotype, genotype and molecular mechanism of recurrent venous thrombosis in two Chinese pedigrees with type I antithrombin (AT) deficiency. METHODS: The routine coagulation screening tests were detected, thrombin generation tests was performed to evaluate the hypercoagulation. Anticardiolipin antibody (ACA) and lupus anticoagulant (LA) were detected with enzyme-linked immunosorbent assay (ELISA) and diluted viper venom time assay (DVVT), respectively. The activities of protein C, protein S and AT (PC:A, PS:A, AT:A) were tested with chromogenic substrate assay or clotting method. The antigen of AT (AT:Ag) was performed with immunoturbidimetry methods. Western blot was used to analyze the molecular weight (MW) and the plasma levels of AT:Ag. All 7 exons and the flanking sequences were amplified by PCR. The mutation of AT gene and thrombophilia associated gene polymorphisms were analyzed by direct DNA sequencing. The expression plasmid of Ala404Asp mutant was constructed with site-directed mutagenesis method based on the wild-type (WT) AT cDNA contained in pcDNA 3.1 vector, and transiently expression of AT WT and the Ala404Asp mutant was performed using HEK293T cells. Cultured supernatant and cell lysates were collected and measured for AT:Ag by ELISA and Western blot. RESULTS: The results of routine coagulation tests in two probands were normal, thrombin generation tests indicated that proband 1 presented hypercoagulable state with 2.8 and 1.5 times higher of the endogenous thrombin potential (ETP) and peak height compared with that of normal, respectively. The levels of PC:A, PS:A, ACA and LA were normal. AT:A in proband 1 and proband 2 were 45% and 32%, and AT:Ag were almost half of the normal (121 mg/L and 158 mg/L), respectively. The results of Western blot showed that both probands' plasma levels of AT:Ag were lower than the normal pooled plasma and MW was normal. Two heterozygous mutations of g.3291C→T(Thr98Ile), g.13863C > A(Ala404Asp) were identified in the probands, respectively. No proband had venous thrombosis associated gene polymorphisms. Expression in vitro showed that AT:Ag in culture media and lysates of Ala404Asp are 4.8% and 60.6% of that of WT, respectively. CONCLUSION: Thr98Ile and Ala404Asp mutation of AT gene significantly correlate with recurrent venous thrombosis in the two probands, respectively. Ala404Asp has not been described before. The mutant Ala404Asp protein can not be expressed due to impaired secretion and increased intracellular degradation, resulting in type I AT deficiency.

Cerebral venous thrombosis during pregnancy in the setting of type I antithrombin deficiency: case report and literature review.

Inherited antithrombin deficiency is estimated to carry a 50% risk of a venous thrombotic complication during each pregnancy and puerperium. We present a case of a female with heterozygous type I antithrombin deficiency who presented with a central nervous system transverse sinus thrombosis in the third trimester of pregnancy despite the use of therapeutic doses of low molecular weight heparin, as venous thromboembolic prophylaxis, since conception. A successful pregnancy outcome was achieved with the combined use of therapeutic anticoagulation and regular plasma-derived antithrombin concentrate infusions to normalize her antithrombin levels. This case lends further debate to the issue of whether antithrombin concentrate, in addition to anticoagulation, should be routinely administered for venous thromboembolic prophylaxis during pregnancy and the puerperium to women with inherited antithrombin deficiency. This point may become more relevant as further experience is gained with the use of recombinant human antithrombin.

Coagulación intravascular diseminada / Disseminated intravascular coagulation

La coagulación intravascular diseminada (CID) es una entidad clínica frecuente que se presenta como fenómeno secundario a diversas enfermedades entre las cuales se destacan las infecciones graves, las neoplasias y las catástrofes obstétricas. Se caracteriza por una activación difusa y simultánea de los sistemas endógenos de la coagulación y la fibrinólisis. El depósito de pequeños trombos en la circulación conduce finalmente a disfunción orgánica múltiple y en algunos casos a la muerte. Las manifestaciones clínicas pueden incluir fenómenos trombóticos y hemorrágicos. Se ha propuesto un puntaje de fácil aplicación para simplificar el diagnóstico de la entidad. El tratamiento incluye el control específico de la causa subyacente que favorece la aparición de la CID, el soporte con hemoderivados en pacientes con manifestaciones de sangrado y la anticoagulación terapéutica en pacientes con trombosis mayores. El desarrollo de CID es un factor pronóstico adverso que aumenta significativamente la tasa de mortalidad. En este artículo de revisión se incluyen los siguientes aspectos de la CID: historia, epidemiología, clasificación, entidades asociadas, fisiopatología, clínica, diagnóstico, tratamiento y pronóstico.

Disseminated intravascular coagulation (DIC) is a frequent clinical entity that presents as a secondary phenomenon associated with some diseases, including, among others, severe infections, neoplastic disorders and obstetric catastrophes. It is characterized by a diffuse and simultaneous activation of the clotting and fibrinolytic systems. The deposit of small thrombi in the circulation eventually leads to dysfunction of multiple organs, and in some cases to death. Clinical findings include thrombotic as well as hemorrhagic manifestations. A simple scoring system has been proposed to aid in the diagnosis of this entity. Treatment includes the specific management of the underlying cause that triggered the DIC, support with blood products in patients with bleeding manifestations and therapeutic anticoagulation in patients with thrombotic events. The development of DIC is an adverse prognostic factor that significantly increases mortality. In this review article the following aspects of CID are included: history, epidemiology, classification, associated diseases, physiopathology, clinical presentation, diagnosis, treatment and prognosis.

Recombinant factor VIIa reduces bleeding after blunt liver injury in coagulopathic, hypofibrinogenaemic pigs.

BACKGROUND: Recombinant factor VIIa (rFVIIa) has been successfully used in various clinical conditions to treat severe coagulopathy, but its efficacy may be affected by the underlying conditions. We therefore investigated the efficacy of rFVIIa treatment under conditions of hypofibrinogenaemia in a pig model of blunt liver injury. METHODS: Severe haemodilution was instigated in four groups of seven anaesthetized pigs. Before inflicting liver injury, animals were assigned to receive either 70 mg kg(-1) fibrinogen (fibrinogen group) or placebo (control group). Thirty seconds after injury, rFVIIa (180 µg kg(-1)) (rFVIIa and fibrinogen+rFVIIa groups) or vehicle (control and fibrinogen groups) was administered. Haemodynamic variables, coagulation parameters, and blood loss were monitored for 2 h. Histology was examined to evaluate the presence of thrombi and the consistency of liver injury. RESULTS: At the end of the observation period, total blood loss [median (range)] decreased in all intervention groups [fibrinogen: 1275 (1221-1439) ml, P=0.036; rFVIIa: 966 (923-1136) ml, P=0.008; fibrinogen+rFVIIa: 678 (475-756) ml, P=0.008] when compared with control animals [blood loss: 1752 (1735-2221) ml]. The mortality rate in the control group was 100%, whereas only 42% of fibrinogen-substituted animals died (P=0.023). All animals treated with rFVIIa or fibrinogen+rFVIIa (P<0.001) survived and no signs of thromboembolism were observed. CONCLUSIONS: rFVIIa under conditions of hypofibrinogenaemia exhibited a positive impact on coagulation parameters and a reduction in blood loss. These effects were significantly improved after prior substitution with fibrinogen.

Neither fibrin nor plasminogen activator inhibitor-1 deficiency protects lung function in a mouse model of acute lung injury.

Fibrin impairs surfactant function in vitro, and inhibition of fibrinolysis by plasminogen activator inhibitor (PAI-1) is thought to promote fibrin accumulation in acute lung injury (ALI). This has led to speculation that impaired PAI-1 and fibrin accumulation should protect lung function in ALI. We tested this hypothesis by investigating ALI severity in fibrinogen-deficient (Fgn-/-) and PAI-1-deficient (PAI-1-/-) mice. PAI-1-/-, C57BL/6, Fgn-/-, and Fgn+/- females were anesthetized and allowed to aspirate 4 microl/g of hydrochloric acid (pH 1.0) and then reanesthetized and connected to a ventilator 48 h later. Naive C57BL/6 and Fgn+/- females served as controls. Following deep inflation (DI), forced oscillations were delivered periodically over 8 min to measure changes in elastance (H) as a surrogate of lung derecruitment, at positive end-expiratory pressures (PEEP) of 6, 3, and 1 cmH(2)O. Increases in H following DI in acid-injured mice were greater than naive strain-matched controls. Increases in H were no different between injured PAI-1-/- and C57BL/6, or between injured Fgn-/- and +/- mice, at any PEEP. Pressure-volume curves were no different between injured groups. Total lung fibrin was lower in injured PAI-1-/- and Fgn-/- mice relative to injured C57BL/6 and Fgn+/- mice, respectively, but indices of permeability were no different between strains. Unexpectedly, neither fibrin nor PAI-1 deficiency protects lung mechanical function in mice with acid-induced ALI. We speculate that in vivo lung function may be more closely tied to permeability and alveolar protein in general, rather than being linked specifically to fibrin.