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1.
Nature ; 623(7989): 932-937, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38030780

RESUMEN

Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕ to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

2.
Nature ; 557(7703): 68-70, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29720632

RESUMEN

Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable species in the atmospheres of exoplanets, especially in extended and escaping atmospheres 1 . Searches for helium, however, have hitherto been unsuccessful 2 . Here we report observations of helium on an exoplanet, at a confidence level of 4.5 standard deviations. We measured the near-infrared transmission spectrum of the warm gas giant 3 WASP-107b and identified the narrow absorption feature of excited metastable helium at 10,833 angstroms. The amplitude of the feature, in transit depth, is 0.049 ± 0.011 per cent in a bandpass of 98 angstroms, which is more than five times greater than what could be caused by nominal stellar chromospheric activity. This large absorption signal suggests that WASP-107b has an extended atmosphere that is eroding at a total rate of 1010 to 3 × 1011 grams per second (0.1-4 per cent of its total mass per billion years), and may have a comet-like tail of gas shaped by radiation pressure.

3.
Nature ; 460(7259): 1098-100, 2009 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-19713926

RESUMEN

The 'hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only approximately 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M(Jup)), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10(6), as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System.

4.
Water Environ Res ; 87(2): 132-44, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25790516

RESUMEN

In the Water Framework Directive, a list of priority substances that are deemed to be persistent, toxic, and liable to bioaccumulate have been identified. Within this list, a range of polycyclic aromatic hydrocarbons (PAHs) and certain trace metals are relevant to the steel industry. This study summarizes work carried out by Tata Steel Europe (Rotherham, U.K.) to characterize the emissions of PAHs and trace metals from wastewater streams at one of its main integrated steelworks in the United Kingdom over a 3-year period (2010 to 2012). The emissions inventory revealed that PAH emissions to water were almost entirely attributable to the cokemaking process, with emissions factors ranging from 20 to 55 mg/tonne of coke. Furthermore, analysis of the PAH distribution in coke oven effluents revealed that medium- and high-molecular-weight PAHs were associated with the suspended solids (particle-bound). Regarding trace metals, both ironmaking and steelmaking processes were the most important emission sources.


Asunto(s)
Metalurgia , Metales Pesados/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Concentración Máxima Admisible , Reino Unido
5.
Ecology ; 95(3): 627-30, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24804444

RESUMEN

Early statistical methods focused on pre-data probability statements (i.e., data as random variables) such as P values; these are not really inferences nor are P values evidential. Statistical science clung to these principles throughout much of the 20th century as a wide variety of methods were developed for special cases. Looking back, it is clear that the underlying paradigm (i.e., testing and P values) was weak. As Kuhn (1970) suggests, new paradigms have taken the place of earlier ones: this is a goal of good science. New methods have been developed and older methods extended and these allow proper measures of strength of evidence and multimodel inference. It is time to move forward with sound theory and practice for the difficult practical problems that lie ahead. Given data the useful foundation shifts to post-data probability statements such as model probabilities (Akaike weights) or related quantities such as odds ratios and likelihood intervals. These new methods allow formal inference from multiple models in the a prior set. These quantities are properly evidential. The past century was aimed at finding the "best" model and making inferences from it. The goal in the 21st century is to base inference on all the models weighted by their model probabilities (model averaging). Estimates of precision can include model selection uncertainty leading to variances conditional on the model set. The 21st century will be about the quantification of information, proper measures of evidence, and multi-model inference. Nelder (1999:261) concludes, "The most important task before us in developing statistical science is to demolish the P-value culture, which has taken root to a frightening extent in many areas of both pure and applied science and technology".


Asunto(s)
Interpretación Estadística de Datos , Modelos Estadísticos , Proyectos de Investigación
6.
Transfus Med ; 22(6): 383-94, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22630348

RESUMEN

In 2006, the Canadian National Advisory Committee on Blood and Blood Products (NAC) developed a transfusion policy framework for the use of off-label recombinant factor VIIa (rFVIIa) in massive bleeding. Because the number of randomised controlled trials has doubled, the NAC undertook a review of the policy framework in 2011. On the basis of the review of 29 randomised controlled trials, there remains little evidence to support the routine use of rFVIIa in massive bleeding. Mortality benefits have not been demonstrated. Contrarily, an increase in arterial thromboembolic events has been observed with the use of off-label rFVIIa. Given the absence of evidence of benefit and with evidence of the risk of harm, the NAC recommends that recombinant VIIa no longer be used for the off-label indications of prevention and treatment of bleeding in patients without haemophilia.


Asunto(s)
Factor VIIa/efectos adversos , Factor VIIa/uso terapéutico , Hemorragia/tratamiento farmacológico , Uso Fuera de lo Indicado , Humanos , Guías de Práctica Clínica como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/uso terapéutico
7.
Science ; 213(4514): 1321-6, 1981 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-17732555

RESUMEN

Fine-grained clay formations within stable (predictable) deep-sea regions away from lithospheric plate boundaries and productive surface waters have properties that might serve to permanently isolate radioactive waste. The most important characteristics of such clays are their vertical and lateral unifomity, low permeability, very high cation retention capacity, and potential for self-healing when disturbed. The most attractive abyssal clay formation (oxidized red ciay)covers nearly 30 percent of the sea floor and hence 20 percent of the earth's surface.

8.
Sci Total Environ ; 666: 31-38, 2019 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-30784820

RESUMEN

Under the Industrial Emissions Directive (IED), coke production wastewater must be treated to produce an effluent characterised by a total nitrogen (TN) <50 mg/L. An anoxic-aerobic activated sludge pilot-plant (1 m3) fed with coke production wastewater was used to investigate the optimal operational requirements to achieve such an effluent. The loading rates applied to the pilot-plant varied between 0.198-0.418 kg COD/m3.day and 0.029-0.081 kg TN/m3.day, respectively. The ammonia (NH4+-N) removals were maintained at 96%, after alkalinity addition. Under all conditions, phenol and SCN- remained stable at 96% and 100%, respectively with both being utilised as carbon sources during denitrification. The obtained results showed that influent soluble chemical oxygen demand (sCOD) to TN ratio of should be maintained at >5.7 to produce an effluent TN <50 mg/L. Furthermore, nitrite accumulation was observed under all conditions indicating a disturbance to the denitrification pathway. Overall, the anoxic-aerobic activated sludge process was shown to be a robust and reliable technology to treat coke making wastewater and achieve the IED requirements. Nevertheless, the influent to the anoxic tank should be monitored to ensure a sCOD:TN ratio >5.7 or, alternately, the addition of an external carbon source should be considered.


Asunto(s)
Desnitrificación , Residuos Industriales/análisis , Nitrógeno/metabolismo , Aguas del Alcantarillado/análisis , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/análisis , Coque , Proyectos Piloto
9.
J Thromb Haemost ; 5(8): 1650-3, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17488349

RESUMEN

BACKGROUND: Central venous catheters in patients with cancer are associated with development of deep vein thrombosis (DVT); however, there is no accepted standard treatment. OBJECTIVES: To assess the safety and effectiveness of a management strategy for central venous catheter-related DVT in cancer patients consisting of dalteparin and warfarin without the need for line removal. PATIENTS/METHODS: Patients older than 18 years of age with an active malignancy and who had symptomatic, acute, objectively documented UEDVT were eligible. Patients were treated with dalteparin 200 IU kg(-1) per day for 5-7 days and warfarin with a target International Normalized Ratio of 2.0-3.0. Patients were followed for 3 months for recurrent venous thromboembolism, major hemorrhage and survival of the central venous catheter. RESULTS: There were 74 patients (48 males). The average age was 58 years. There were no episodes of recurrent venous thromboembolism and three (4%) major bleeds. No lines were removed because of infusion failure or recurrence/extension of DVT. CONCLUSION: Treatment of UEDVTs secondary to central catheters in cancer patients with standard dalteparin/warfarin can allow the central line to remain in situ with little risk of line failure or recurrence/extension of the DVT.


Asunto(s)
Anticoagulantes/administración & dosificación , Cateterismo Venoso Central/métodos , Dalteparina/administración & dosificación , Neoplasias/tratamiento farmacológico , Trombosis de la Vena/complicaciones , Trombosis de la Vena/tratamiento farmacológico , Warfarina/administración & dosificación , Anciano , Estudios de Cohortes , Femenino , Humanos , Relación Normalizada Internacional , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Proyectos Piloto , Resultado del Tratamiento
10.
Biochim Biophys Acta ; 379(2): 571-81, 1975 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-804323

RESUMEN

Introduction of Ca2+ (greater than 1 mM) into erythrocytes during hemolysis causes formation of an aggregate which is highly resistant to disruption by sodium dodecyl-sulfate and other denaturing agents. The process is temperature dependent, but it does not require incubation in isotonic medium. Aggregation can be prevented but not reversed with chelating agents such as ATP or EDTA. The aggregate can be isolated by chromatography in dodecylsulfate on Sepharose 4B. Its amino acid composition indicates that it contains spectrin as the primary, but not exclusive, polypeptide component. Aggregate formation does not require increased Ca2+ binding to the membranes, and no 45Ca2+ could be detected in the aggregate which had been separated by acrylamide electrophoresis on sodium dodecylsulfate. This indicates that the Ca2+ is important in the formation of the aggregate, but not in its stabilization or maintenance once it has been formed.


Asunto(s)
Proteínas Sanguíneas , Calcio , Eritrocitos/análisis , Aminoácidos/análisis , Sitios de Unión , Proteínas Sanguíneas/aislamiento & purificación , Calcio/farmacología , Agregación Celular/efectos de los fármacos , Membrana Celular/análisis , Cromatografía en Gel , Ácido Edético , Electroforesis en Gel de Poliacrilamida , Humanos , Sustancias Macromoleculares , Unión Proteica , Temperatura
11.
Circulation ; 110(12): 1658-63, 2004 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-15364803

RESUMEN

BACKGROUND: When warfarin is interrupted for surgery, low-molecular-weight heparin is often used as bridging therapy. However, this practice has never been evaluated in a large prospective study. This study was designed to assess the efficacy and safety of bridging therapy with low-molecular-weight heparin initiated out of hospital. METHODS AND RESULTS: This was a prospective, multicenter, single-arm cohort study of patients at high risk of arterial embolism (prosthetic valves and atrial fibrillation with a major risk factor). Warfarin was held for 5 days preoperatively. Low-molecular-weight heparin was given 3 days preoperatively and at least 4 days postoperatively. Patients were followed up for 3 months for thromboembolism and bleeding. Eleven Canadian tertiary care academic centers participated; 224 patients were enrolled. Eight patients (3.6%; 95% CI, 1.8 to 6.9) had an episode of thromboembolism, of which 2 (0.9%; 95% CI, 0.2 to 3.2) were judged to be due to cardioembolism. Of these 8 episodes of thromboembolism, 6 occurred in patients who had warfarin deferred or withdrawn because of bleeding. There were 15 episodes of major bleeding (6.7%; 95% CI, 4.1 to 10.8): 8 occurred intraoperatively or early postoperatively before low-molecular-weight heparin was restarted, 5 occurred in the first postoperative week after low-molecular-weight heparin was restarted, and 2 occurred well after low-molecular-weight heparin was stopped. There were no deaths. CONCLUSIONS: Bridging therapy with subcutaneous low-molecular-weight heparin is feasible; however, the optimal approach for the management of patients who require temporary interruption of warfarin to have invasive procedures is uncertain.


Asunto(s)
Anticoagulantes/uso terapéutico , Arteriopatías Oclusivas/prevención & control , Fibrilación Atrial/cirugía , Dalteparina/uso terapéutico , Implantación de Prótesis de Válvulas Cardíacas , Complicaciones Intraoperatorias/prevención & control , Complicaciones Posoperatorias/prevención & control , Premedicación , Tromboembolia/prevención & control , Warfarina/administración & dosificación , Anticoagulantes/administración & dosificación , Anticoagulantes/efectos adversos , Arteriopatías Oclusivas/epidemiología , Aspirina/administración & dosificación , Pérdida de Sangre Quirúrgica , Estudios de Cohortes , Dalteparina/administración & dosificación , Dalteparina/efectos adversos , Procedimientos Quirúrgicos Electivos , Estudios de Factibilidad , Humanos , Relación Normalizada Internacional , Complicaciones Intraoperatorias/epidemiología , Complicaciones Posoperatorias/epidemiología , Hemorragia Posoperatoria/inducido químicamente , Cuidados Preoperatorios , Estudios Prospectivos , Riesgo , Tromboembolia/epidemiología , Resultado del Tratamiento , Vitamina K/administración & dosificación
12.
J Thromb Haemost ; 3(5): 943-8, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15869589

RESUMEN

BACKGROUND: Although hormone replacement therapy (HRT) is associated with an increased risk of deep vein thrombosis (DVT), it is not clear if the risk differs in users of combined estrogen-progestin HRT and estrogen-only HRT. METHODS: We prospectively studied postmenopausal women with suspected DVT in whom HRT use status was ascertained and who subsequently had objective diagnostic testing to confirm or exclude DVT. Cases were patients with idiopathic DVT, in whom there were no DVT risk factors, and controls were patients without DVT, in whom there were also no DVT risk factors. The risk of DVT was determined in users of estrogen-progestin HRT and estrogen-only HRT by comparing the prevalence of current HRT use in cases with idiopathic DVT and controls without DVT (reference group). Multivariable regression analysis was done to adjust for factors that might confound an association between HRT use and the risk of DVT. RESULTS: One thousand one hundred and sixty-eight postmenopausal women with suspected DVT were assessed, from whom 95 cases of idiopathic DVT and 610 controls without DVT and no DVT risk factors were identified. Estrogen-only HRT was associated with an increased risk for DVT that was not statistically significant [odds ratio (OR) = 1.22; 95% confidence interval (CI) 0.57, 2.61]. Estrogen-progestin HRT was associated with a greater than 2-fold increased risk for DVT (OR = 2.70; 95% CI 1.44, 5.07). CONCLUSION: The risk of developing DVT may be higher in users of combined estrogen-progestin HRT than in users of estrogen-only HRT.


Asunto(s)
Terapia de Reemplazo de Estrógeno/efectos adversos , Trombosis de la Vena/etiología , Anciano , Índice de Masa Corporal , Estudios de Casos y Controles , Estrógenos/efectos adversos , Femenino , Humanos , Persona de Mediana Edad , Análisis Multivariante , Oportunidad Relativa , Posmenopausia , Progestinas/efectos adversos , Estudios Prospectivos , Riesgo , Factores de Riesgo
13.
J Thromb Haemost ; 3(4): 718-23, 2005 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15733061

RESUMEN

BACKGROUND: The post-thrombotic syndrome is a chronic, poorly understood complication of deep venous thrombosis (DVT). OBJECTIVES: To evaluate predictors of the post-thrombotic syndrome, including intensity of long-term anticoagulation, and to assess the impact of the post-thrombotic syndrome on quality of life. PATIENTS AND METHODS: The setting was 13 Canadian hospitals and one US hospital. One hundred and forty-five patients with an unprovoked episode of proximal DVT who were initially treated with 3 months of conventional-intensity warfarin [target International Normalized Ratio (INR) of 2.5] then participated in a trial comparing two intensities of long-term warfarin therapy (target INR 2.5 vs. INR 1.7). Post-thrombotic syndrome was assessed at the end of the trial using a validated clinical scale. Generic and venous disease-specific quality of life was compared in patients with and without the post-thrombotic syndrome. Multivariable regression analyses were performed to identify predictors of the post-thrombotic syndrome and of its severity. RESULTS: After an average follow-up of 2.2 years, the prevalence of post-thrombotic syndrome was 37% and of severe post-thrombotic syndrome was 4%. Quality of life was worse in patients with the post-thrombotic syndrome compared with patients who did not have it. The presence of factor (F)V Leiden or the prothrombin gene mutation was an independent predictor of both a lower risk (P = 0.006) and reduced severity (P = 0.045) of the post-thrombotic syndrome. Intensity of anticoagulation did not influence the risk of developing the post-thrombotic syndrome. CONCLUSIONS: The post-thrombotic syndrome is a frequent and burdensome complication of proximal DVT, even among patients maintained on long-term oral anticoagulation. While the presence of FV Leiden or prothrombin gene mutation appears to be associated with a reduced risk of post-thrombotic syndrome, this finding requires further evaluation in prospective studies.


Asunto(s)
Síndrome Posflebítico/diagnóstico , Trombosis de la Vena/complicaciones , Trombosis de la Vena/terapia , Administración Oral , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anticoagulantes/uso terapéutico , Canadá , Factor V/genética , Femenino , Humanos , Relación Normalizada Internacional , Masculino , Persona de Mediana Edad , Análisis Multivariante , Mutación , Prevalencia , Protrombina/genética , Calidad de Vida , Riesgo , Factores de Tiempo , Estados Unidos , Warfarina/uso terapéutico
14.
Arch Intern Med ; 153(12): 1441-7, 1993 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-8512435

RESUMEN

BACKGROUND: The anticoagulant activity of warfarin sodium is monitored by the prothrombin time (PT). The introduction of a portable PT monitor has raised the possibility that patients could reduce the inconvenience of anticoagulant therapy by measuring their PT at home. We performed this study to determine the feasibility and accuracy of home use of the portable PT monitor. METHODS: A prospective cohort study was performed in consecutive eligible patients who required long-term anticoagulant therapy. Patients performed multiple measurements of their PT at home by means of the portable monitor and at their usual laboratory within a 4-hour interval. The accuracy of the portable monitor was evaluated by two criteria for agreement. Standard agreement was achieved if the portable monitor and laboratory results were both either within or outside the patient's targeted therapeutic range or if the two results were within 0.4 international normalized ratio units of each other. Expanded agreement was achieved if both the portable monitor and laboratory results were within +/- 0.4 international normalized ratio units of the targeted therapeutic range. RESULTS: Forty patients (19 men and 21 women, aged 25 to 74 years) were followed up for 6 to 24 months by means of the portable PT monitor. The mean level of agreement achieved per patient was 83% (95% confidence interval, 79% to 87%) by the standard criteria and 96% (95% confidence interval, 94% to 98%) by the expanded criteria. Twenty-seven patients (68%) and 39 patients (98%) achieved more than 80% agreement by the standard and the expanded criteria, respectively. Questionnaire results revealed that 97% of the patients preferred using the portable monitor to measure their PT. CONCLUSIONS: Patients receiving long-term anticoagulant therapy achieved a high rate of clinically important agreement between self-measurements of the PT with the use of a portable monitor and laboratory PT results. Patients strongly preferred using the portable monitor to measure their PT levels. The use of the portable monitor as the primary method for measuring the PT can be recommended in selected patients receiving long-term anticoagulant treatment.


Asunto(s)
Anticoagulantes/uso terapéutico , Monitoreo de Drogas/instrumentación , Tiempo de Protrombina , Administración Oral , Adulto , Anciano , Anticoagulantes/administración & dosificación , Monitoreo de Drogas/métodos , Diseño de Equipo , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Autocuidado/instrumentación , Encuestas y Cuestionarios
15.
Arch Intern Med ; 154(18): 2101-6, 1994 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-8092915

RESUMEN

Varicella, usually a benign infection of childhood, is known to be associated with more serious complications, especially in adults and immunocompromised patients. Of these, varicella pneumonitis is the most common. Primary varicella hepatitis has been described, though rarely, in immunocompromised patients. We present a case of a previously healthy human immunodeficiency virus-negative 26-year-old immigrant from El Salvador in whom primary varicella developed that rapidly progressed to fulminant hepatic failure, disseminated intravascular coagulation, and death. Autopsy revealed evidence of varicella in the liver, adrenal glands, and myometrium. To our knowledge, this is the first report of a fatal case of varicella hepatitis in a previously healthy, immunocompetent patient.


Asunto(s)
Varicela/complicaciones , Encefalopatía Hepática/microbiología , Adulto , Varicela/patología , Coagulación Intravascular Diseminada/microbiología , Resultado Fatal , Femenino , Encefalopatía Hepática/patología , Humanos
16.
Arch Intern Med ; 153(7): 841-4, 1993 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-8466376

RESUMEN

BACKGROUND: The use of subcutaneous heparin, the therapy of choice for women requiring anticoagulant prophylaxis during pregnancy, is problematic because of the discomfort produced by repeated injections. An indwelling subcutaneous Teflon catheter that can be left in place for 1 week recently became available for use as an entry port for parenteral therapy. Since the use of this catheter has the potential to overcome some of the problems of long-term heparin therapy, we decided to compare this Teflon catheter with twice-daily subcutaneous injections in women requiring heparin during pregnancy. METHODS: In a randomized, multiple-crossover study, patients alternated every 2 weeks between having heparin administered through the indwelling Teflon catheter and receiving heparin via subcutaneous injections. After each 4-week cycle, patients completed a questionnaire designed to determine their preferred method of heparin administration. The side effects, doses, and anticoagulant activity of heparin with the two delivery systems were also compared. RESULTS: Twelve patients completed one to five 4-week cycles of heparin therapy. Ten of the patients selected the Teflon catheter as the preferred route of heparin administration (P = .04) and 11 patients reported that the catheter caused less pain and bruising than twice-daily subcutaneous injections (P < .01). Five patients developed urticarial reactions at the sites of heparin injections. These reactions tended to be more severe when the Teflon catheter was used, and two women discontinued using the catheter after the first cycle because of this complication. There were no differences in heparin dose requirements or achieved activated partial thromboplastin times between the two routes of heparin administration. CONCLUSIONS: Most pregnant women in our study preferred to have subcutaneous heparin administered through an indwelling Teflon catheter rather than by twice-daily injections. Heparin given through the Teflon catheter was bioavailable and caused less local bruising than twice-daily injections. Urticarial reactions to heparin tended to be more severe with the use of the Teflon catheter and resulted in the discontinuation of the device's use in two of 12 patients.


Asunto(s)
Catéteres de Permanencia , Heparina/administración & dosificación , Inyecciones Subcutáneas/instrumentación , Complicaciones Hematológicas del Embarazo/tratamiento farmacológico , Adulto , Femenino , Humanos , Inyecciones Subcutáneas/efectos adversos , Dolor/etiología , Dolor/prevención & control , Politetrafluoroetileno , Embarazo , Autoadministración/instrumentación
17.
Arch Intern Med ; 161(11): 1405-10, 2001 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-11386889

RESUMEN

BACKGROUND: Some of the benefit of statins for the prevention of cardiovascular disease may be due to their antithrombotic properties. Little is known about the effect of these drugs on the development of deep vein thrombosis. MATERIALS AND METHODS: We conducted a retrospective cohort study over an 8-year period by linking Ontario provincial health care administrative databases covering more than 1.4 million Ontario residents aged 65 years or older. We excluded those with a documented history of atherosclerosis, venous thromboembolism, or cancer within 36 months prior to study enrollment, as well as those prescribed warfarin sodium within 12 months before enrollment. In the primary cohort, we evaluated the subsequent risk of deep vein thrombosis (DVT) among men and women prescribed thyroid replacement therapy, nonstatin lipid-lowering agents, or statins. A second cohort of women only was evaluated in a similar fashion, but estrogen use was added as a third comparison drug group. RESULTS: There were 125 862 men and women in the primary cohort. After adjusting for age; sex; prior hospitalization; newly diagnosed cancer; or prescribed aspirin, warfarin, or estrogen, statin users (n = 77 993) had an associated decreased risk of DVT relative to those prescribed thyroid replacement therapy (n = 35 978) (adjusted hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.69-0.87). Compared with thyroid replacement therapy, users of nonstatin lipid-lowering agents (n = 11 891) did not seem to be at lower risk for deep vein thrombosis (HR, 0.97; 95% CI, 0.79-1.18). In the secondary cohort of 89 508 women, after adjusting for age, prior hospitalization, newly diagnosed cancer, or prescribed aspirin or warfarin, estrogen users (n = 29 165) had an associated increased risk for DVT compared with those receiving thyroid replacement therapy (n = 22 118) (HR, 1.16; 95% CI, 1.01-1.33), while statin users had an associated decreased risk (HR, 0.68; 95% CI, 0.59-0.79). Nonstatin lipid-lowering agents (n = 5155) were not associated with a reduced risk of DVT compared with thyroid replacement therapy (HR, 0.84; 95% CI, 0.63-1.12). CONCLUSION: Among selected individuals aged 65 years or older, statins were associated with a 22% relative risk reduction in the risk of DVT. A randomized clinical trial is needed to evaluate the efficacy of statins for the primary and secondary prevention of DVT.


Asunto(s)
Anticolesterolemiantes/uso terapéutico , Lovastatina/uso terapéutico , Trombosis de la Vena/prevención & control , Anciano , Estudios de Cohortes , Estrógenos/uso terapéutico , Femenino , Humanos , Masculino , Análisis Multivariante , Estudios Retrospectivos , Factores de Riesgo , Hormonas Tiroideas/uso terapéutico
18.
Arch Intern Med ; 159(5): 477-82, 1999 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-10074956

RESUMEN

CONTEXT: The management of patients presenting to hospital emergency departments with suspected deep vein thrombosis (DVT) is problematic because urgent diagnostic imaging capability is sometimes unavailable. Experienced physicians using clinical skills alone can classify patients with suspected DVT into low-, moderate-, and high-probability categories. OBJECTIVES: To determine the accuracy of an explicit clinical model for the diagnosis of DVT when applied by emergency department physicians and to assess the safety and feasibility of a management strategy based on the clinical pretest probability for patients presenting to the emergency department with suspected DVT outside of regular hospital staff work hours. METHODS: A prospective cohort study was performed in the emergency departments of 2 tertiary care institutions involving 344 patients with suspected DVT. Patient conditions were evaluated by an emergency department physician who determined the pretest probability for DVT to be low, moderate, or high using an explicit clinical model. Patients for whom DVT was considered a low pretest probability were discharged from the emergency department and returned the following day for venous compression ultrasound imaging of the affected leg. Patients for whom DVT was considered a moderate pre-test probability received a single, weight-adjusted dose of subcutaneous unfractionated heparin sodium (between 12 500 and 20 000 U), were discharged from the emergency department, and returned the next morning to undergo ultrasonography. Patients for whom DVT was considered a high pretest probability were admitted to the hospital, administered intravenous unfractionated heparin, and ultrasonography was arranged within 24 hours. Patients with positive ultrasonographic findings were diagnosed with DVT, except for those with low pretest probability for whom confirmatory venography was performed. Patients with DVT excluded in the initial evaluation period did not receive anticoagulant therapy. All patients were followed up for 90 days to monitor development of thromboembolic or bleeding complications. RESULTS: Twenty-four (49.0% [95% confidence interval (CI), 34.5%-63.6%]) of 49 patients in the high-probability category, 15 (14.3% [95% CI, 8.3%-22.4%]) of 105 in the moderate-, and 6 (3.2% [95% CI, 1.2%-6.7%]) of 190 in the low-probability category were confirmed to have DVT. Overall, 45 (13.1%) of 344 patients were confirmed to have DVT. No patient developed pulmonary embolism or major bleeding complications within 48 hours of initial evaluation in the emergency department. Of the 301 patients who had DVT excluded during the initial evaluation period, only 2 (0.7% [95% CI, 0.1%-2.3%]) developed venous thromboembolic complications (calf vein thromboses in both) in the 3-month follow-up period. CONCLUSIONS: Using an explicit clinical model, emergency department physicians can accurately classify patients with suspected DVT into high-, moderate-, and low-probability groups. A management plan based on probability for DVT that avoids the need for urgent diagnostic imaging is safe and feasible in the emergency department setting.


Asunto(s)
Trombosis/diagnóstico , Árboles de Decisión , Diagnóstico Diferencial , Servicio de Urgencia en Hospital , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Admisión del Paciente , Flebografía , Valor Predictivo de las Pruebas , Estudios Prospectivos , Trombosis/diagnóstico por imagen , Trombosis/tratamiento farmacológico , Ultrasonografía
19.
J Thromb Haemost ; 13(3): 398-408, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25495610

RESUMEN

BACKGROUND: Post-thrombotic syndrome (PTS) is a frequent chronic complication of deep vein thrombosis (DVT). OBJECTIVE: In the BioSOX study, we investigated whether inflammation markers predict the risk of PTS after DVT. METHODS: We measured C-reactive protein (CRP), ICAM-1, interleukin (IL)-6, and IL-10, at baseline, and 1 month and 6 months after a first proximal DVT, among 803 participants in the SOX trial. Participants were prospectively followed for 24 months for development of PTS. RESULTS: Median CRP levels at 1 month, ICAM-1 levels at baseline, 1 month and 6 months, IL-6 levels at 1 month and 6 months and IL-10 levels at 6 months were higher in patients who developed PTS than in those who did not. Multivariable regression with the median as a cutoff showed risk ratios (RRs) for PTS of 1.23 (95% confidence interval [CI] 1.05-1.45) and 1.25 (95% CI 1.05-1.48) for ICAM-1 at 1 month and 6 months, respectively, and 1.27 (95% CI 1.07-1.51) for IL-10 at 6 months. Quartile-based analysis demonstrated a dose-response association between ICAM-1 and PTS. ICAM-1 and IL-10 were also associated with PTS severity. Analysis of biomarker trajectories after DVT demonstrated an association between the highest-trajectory group of ICAM-1 and PTS. CONCLUSIONS: In this prospective study, ICAM-1 over time was most consistently associated with the risk of PTS. Further study is required to confirm these findings and assess their potential clinical relevance.


Asunto(s)
Mediadores de Inflamación/sangre , Molécula 1 de Adhesión Intercelular/sangre , Síndrome Postrombótico/etiología , Trombosis de la Vena/sangre , Adulto , Anciano , Biomarcadores/sangre , Proteína C-Reactiva/metabolismo , Canadá , Distribución de Chi-Cuadrado , Femenino , Estudios de Seguimiento , Humanos , Interleucina-10/sangre , Interleucina-6/sangre , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Oportunidad Relativa , Síndrome Postrombótico/diagnóstico , Síndrome Postrombótico/prevención & control , Estudios Prospectivos , Medición de Riesgo , Factores de Riesgo , Índice de Severidad de la Enfermedad , Medias de Compresión , Factores de Tiempo , Resultado del Tratamiento , Estados Unidos , Trombosis de la Vena/complicaciones , Trombosis de la Vena/diagnóstico , Trombosis de la Vena/terapia
20.
J Immunother (1991) ; 11(4): 267-73, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1599912

RESUMEN

Two murine monoclonal antibodies, 8A6 and 8C2, were generated against the carbohydrate moiety of tumor-associated disialoganglioside. Both of the antibodies were of the immunoglobulin G3 (IgG3), K isotype subclass. One of these antibodies (8A6) was used as a network immunogen for the generation of anti-idiotype antibodies. Two AB2 anti-idiotype antibodies were identified. One AB2 (12E5) was subsequently shown to recognize a linear epitope of the 8A6 kappa light chain. The second AB2 (9H8), recognizes a conformational epitope which is dependent on the maintenance of the tertiary structure of the idiotype. Both anti-idiotypes were injected into (syngeneic) mice and (xenogeneic) rabbits to evaluate their effectiveness as "network" antigens in promoting AB3 and anti-carbohydrate AB1' responses. AB3 populations from both syngeneic and xenogeneic hosts were found to be idiotype-specific, yet were unable to produce a measurable subpopulation of anti-tumor (AB1'). These studies suggest that IgG3 isotypes may not be suitable idiotype templates for the mimicry of carbohydrate epitopes.


Asunto(s)
Anticuerpos Antiidiotipos/biosíntesis , Carbohidratos/inmunología , Inmunoglobulina G , Animales , Antígenos de Carbohidratos Asociados a Tumores , Femenino , Gangliósidos/inmunología , Humanos , Inmunización , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Conejos
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