Development of Coagulation Factor XII Antibodies for Inhibiting Vascular Device-Related Thrombosis.

INTRODUCTION: Vascular devices such as stents, hemodialyzers, and membrane oxygenators can activate blood coagulation and often require the use of systemic anticoagulants to selectively prevent intravascular thrombotic/embolic events or extracorporeal device failure. Coagulation factor (F)XII of the contact activation system has been shown to play an important role in initiating vascular device surface-initiated thrombus formation. As FXII is dispensable for hemostasis, targeting the contact activation system holds promise as a significantly safer strategy than traditional antithrombotics for preventing vascular device-associated thrombosis. OBJECTIVE: Generate and characterize anti-FXII monoclonal antibodies that inhibit FXII activation or activity. METHODS: Monoclonal antibodies against FXII were generated in FXII-deficient mice and evaluated for their binding and anticoagulant properties in purified and plasma systems, in whole blood flow-based assays, and in an in vivo non-human primate model of vascular device-initiated thrombus formation. RESULTS: A FXII antibody screen identified over 400 candidates, which were evaluated in binding studies and clotting assays. One non-inhibitor and six inhibitor antibodies were selected for characterization in functional assays. The most potent inhibitory antibody, 1B2, was found to prolong clotting times, inhibit fibrin generation on collagen under shear, and inhibit platelet deposition and fibrin formation in an extracorporeal membrane oxygenator deployed in a non-human primate. CONCLUSION: Selective contact activation inhibitors hold potential as useful tools for research applications as well as safe and effective inhibitors of vascular device-related thrombosis.

Group V secretory phospholipase A2 impairs endothelial protein C receptor-dependent protein C activation and accelerates thrombosis in vivo.

BACKGROUND: Endothelial protein C receptor (EPCR) must be bound to a molecule of phosphatidylcholine (PC) to be fully functional, i.e. to interact with protein C/activated protein C (APC) properly. PC can be replaced with other lipids, such as lysophosphatidylcholine or platelet-activating factor, by the action of group V secretory phospholipase A2 (sPLA2-V), an enzyme that is upregulated in a variety of inflammatory conditions. Studies in purified systems have demonstrated that the substitution of PC notably impairs EPCR function in a process called EPCR encryption. OBJECTIVES: To analyze whether sPLA2-V was able to regulate EPCR-dependent protein C activation in vivo, and its impact on thrombosis and the hemostatic system. METHODS: Mice were transfected with sPLA2-V by hydrodynamic gene delivery. The effects on thrombosis were studied with the laser carotid artery occlusion model, and APC generation capacity was measured with ELISA. Global hemostasis was analyzed with thromboelastometry. RESULTS: We found that sPLA2-V overexpression in mice significantly decreased their ability to generate APC. Furthermore, a murine carotid artery laser thrombosis model revealed that higher sPLA2-V levels were directly associated with faster artery thrombosis. CONCLUSIONS: sPLA2-V plays a thrombogenic role by impairing the ability of EPCR to promote protein C activation.

Factor XII promotes blood coagulation independent of factor XI in the presence of long-chain polyphosphates.

BACKGROUND: Inorganic polyphosphates (polyP), which are secreted by activated platelets (short-chain polyP) and accumulate in some bacteria (long-chain polyP), support the contact activation of factor XII (FXII) and accelerate the activation of FXI. OBJECTIVES: The aim of the present study was to evaluate the role of FXI in polyP-mediated coagulation activation and experimental thrombus formation. METHODS AND RESULTS: Pretreatment of plasma with antibodies that selectively inhibit FXI activation by activated FXII (FXIIa) or FIX) activation by activated FXI (FXIa) were not able to inhibit the procoagulant effect of long or short-chain polyP in plasma. In contrast, the FXIIa inhibitor, corn trypsin inhibitor, blocked the procoagulant effect of long and short polyP in plasma. In a purified system, long polyP significantly enhanced the rate of FXII and prekallikrein activation and the activation of FXI by thrombin but not by FXIIa. In FXI-deficient plasma, long polyP promoted clotting of plasma in an FIX-dependent manner. In a purified system, the activation of FXII and prekallikrein by long polyP promoted FIX activation and prothombin activation. In an ex vivo model of occlusive thrombus formation, inhibition of FXIIa with corn trypsin inhibitor but not of FXI with a neutralizing antibodies abolished the prothrombotic effect of long polyP. CONCLUSIONS: We propose that long polyP promotes FXII-mediated blood coagulation bypassing FXI. Accordingly, some polyp-containing pathogens may have evolved strategies to exploit polyP-initiated FXII activation for virulence, and selective inhibition of FXII may improve the host response to pathogens.

Caries en una población militar española / Dental caries in a Spanish military population

Objetivo: Evaluar la prevalencia de caries de la población militar española de la base «General Almirante» Marines, Valencia. Material y método. Estudio descriptivo transversal para el que se seleccionó una muestra de 387 militares para un IC del 95%. En el gabinete dental de la base se realizó la exploración oral siguiendo los criterios de la OMS (1997, 4ª edición). Un solo profesional experimentado con un explorador patrón llevó a cabo la encuesta entre diciembre del 2003 y julio del 2004. Resultados. El índice de dientes con caries, ausentes y obturados (CAO-D) fue de 4,05. El 23% de la muestra estaba libre de caries. Presentaban caries sin tratar el 40% de los explorados, siendo significativamente superior el porcentaje en la tropa y en los que referían no cepillarse de forma regular. El índice de restauración (% O/ CAO-D) fue del 60%. La población de tropa presentó con significación estadística mas caries y menos dientes con caries tratada (A,O) que el grupo de oficiales y suboficiales. Conclusiones. Casi la mitad de la población encuestada precisa tratamiento por caries. Estrategias de asistencia basadas en políticas preventivas de diagnostico precoz y de asistencia personalizada en función del riesgo individual de caries, adaptadas al medio militar, pudieran ser la clave para poder desplegar en un futuro tropas que no ocasionen emergencias en futuras operaciones (AU)

Object: The target of this study was to assess the prevalence of caries in a population of Spanish military personnel at the «General Almirante » base at Marines (Valencia). Material and Method: A descriptive cross-sectional study was made of a sample of 387 military personnel, (95% CI). The oral examinations were conducted at the dental clinic at the base, in accordance with the WHO (1997, 4th ed.) criteria, by a single dentist calibrated against an experienced examiner. The survey was conducted between December 2003 and July 2004. Results: The decayed, missed and filled teeth (DMF-T) were 4.05. The 23% of the sample was free of caries. The 40% of those examined presented untreated caries, the percentage of untreated caries was significantly higher among the privates and among those who did not report regular tooth brushing. The care index (% F/DMF-T) was 60%. The privates presented more decay and less treated caries (M,F) than the officers and non-commissioned officers, these differences were statistically significant. Conclusions: Nearly half of those polled need caries treatment. Strategies based on preventive policy of early diagnosis and Caries management by risk assessment adapted to military life, may be the key to achieving emergency-free troop deployment during future operations (AU)

Dietary habits of a school population and implications for oral health.

AIM: The study analyzes the consumption of cariogenic foods in a population of children between 6 and 10 years old. METHODS: Transversal descriptive study on a sample of 369 children who first attended to the Department 9 Dentistry dental office of the Valencia Region Health Agency (Spain). A self-administered food consumption frequency questionnaire was used to evaluate how often the food on the list were consumed by the children. RESULTS: Sticky sugar-rich foods, sugared milk and dairy products, food containing starch and sugar, sugary liquids and food with semihydrolyzed starch were consumed by over 50% of the sample at main meals and between meals. The mean intake of all these food groups, was over five times a week. The older children ate more fruit and foods rich in semihydrolyzed starch at main meals. Sweetened medication significantly reduced with age. Sugar-free sweets were consumed by almost 60% of the sample. CONCLUSION: The study shows a high intake of food with cariogenic potential, in particular processed food with added sugar and food with semihydrolyzed starch consumed between meals. This situation indicates the need to include health education programs in our population focused to improve the dietary habits of children and teenagers.

Severe and recurrent episodes of bronchiolitis obliterans organising pneumonia associated with indolent CD4+ CD8+ T-cell leukaemia.

The present study describes an adult male who has had recurrent episodes of pulmonary infiltrates with severe acute respiratory failure over a period of 10 yrs. Clinical and pathological characteristics revealed bronchiolitis obliterans with organising pneumonia (BOOP) that responded dramatically to prednisone. BOOP is characterised by inflammation of the bronchioles and surrounding tissue in the lungs. It can mimic infectious pneumonia but diagnosis is suspected when there is no response to multiple antibiotic treatment, and blood and sputum cultures are negative for microorganisms. A high proportion of double-positive (DP)-T-cells was detected in peripheral blood and in bronchoalveolar lavage, expressing CD4 and CD8alphabeta heterodimer with memory phenotype. These DP-T-lymphocytes expressed specific homing molecules that could explain their tropism to lung tissue, giving rise to the clinical symptoms. The patient did not present organomegaly, lymphadenopathy, lymphocytosis or other features of malignancy. However, T-cell receptor Vbeta chain analysis indicated clonal rearrangement, and cytogenetic studies displayed chromosomic alterations that were similar to clonal proliferation observed in ataxia-telangiectasia and T-prolymphocytic leukaemia. The findings suggest a smouldering form of lymphoproliferation, the first sign of which was bronchiolitis obliterans organising pneumonia requiring constant corticoid treatment.

Binding of factor VIIa to the endothelial cell protein C receptor reduces its coagulant activity.

BACKGROUND: Endothelial cell protein C receptor (EPCR) binds protein C through its gamma-carboxyglutamic acid (Gla) domain and enhances its thrombin-thrombomodulin complex-dependent activation. So far, only protein C/activated protein C has been shown to interact with EPCR. Factor VII (FVII), the coagulation trigger upon tissue factor (TF) interaction, is a serine protease whose Gla domain is highly homologous to the Gla domain of protein C. OBJECTIVES: To characterize the binding of FVII/FVIIa to EPCR and its functional consequences. METHODS AND RESULTS: We demonstrated by surface plasmon resonance (SPR) that FVII/FVIIa binds to EPCR through its Gla domain. At therapeutic concentrations, FVIIa reduced the activation of protein C by 40%. Soluble EPCR (sEPCR) was also able to prolong dose-dependently the clotting time induced by the FVIIa-TF complex. SPR and amidolytic experiments showed that FVIIa is able to interact simultaneously with TF and EPCR, thus ruling out the possibility that the effect of EPCR on clotting time was due to the inhibition of the binding between FVIIa and TF. sEPCR inhibited dose-dependently the activation of FX by the FVIIa-TF complex. Notably, blocking the binding site of EPCR on the endothelial surface increased the generation of FXa 2-fold. CONCLUSIONS: EPCR binds to FVII/FVIIa and inhibits the procoagulant activity of the FVIIa-TF complex.

Emergencias de origen oral. Una revisión / No disponible

La importancia de salud general y en especial de la oral, desde el punto de vista militar tiene unas consideraciones y unas repercusiones que le son propias. La primera misión de los servicios de odontología-estomatología militar es mantener la salud oral de nuestros soldados y la de nuestros aliados en un nivel óptimo para asegurar la disponibilidad para el despliegue, los dentistas desplegados tienen que ser capaces de tratar la inmensa mayoría de problemas dentales sin diferirlos, esto es una muestra de la importancia de la necesaria preparación. Las estrategias de prevención son la clave, para poder en un futuro desplegar en situación de aptitud dental; Sin una educación de prevención y un mantenimiento adecuados estos soldados pueden presentar repetidos episodios de necesidad de asistencia. Presentamos una revisión de la tasa de incidencia de emergencias de origen oral y sus causas en los despliegues y maniobras. Se incluyen los criterios diagnósticos que valoran esas situaciones. La tasa de incidencia fue muy variable, entre 52 y 755 asistencias por cada 1000 soldados y año. Ésta depende de muchos elementos, el más estudiado fue el estado de salud previo al despliegue. Las causas más importantes fueron las restauraciones defectuosas y las caries, seguidas de pericoronaritis y de lesiones de origen gingival y periodontal (AU)

No disponible

Methodological considerations in the determination of working length.

AIM: The aim of this study was to evaluate the diagnostic efficacy of an electronic system for the determination of working length, in comparison with two radiological methods (conventional film and digital radiography). METHODOLOGY: The study sample consisted of 28 root canals belonging to 20 human mandibular teeth. A comparison was made between the working length measurements obtained by two radiological methods (conventional film and digital radiography) and an apex locator, using as gold standard the observation of the file position within the root following selective grinding of the root tissue. RESULTS: The electronic method was satisfactory in 67.8% of cases, versus 50.6% and 61.4% for the conventional and digital radiological methods. respectively. No statistically significant differences occurred between the techniques according to the chi-squared and Kruskal-Wallis nonparametric tests. CONCLUSIONS: None of the techniques was totally satisfactory in establishing the true working length. There were no differences between the techniques investigated.