3,089 research outputs found

    Prevention and management of acute reactions to intravenous iron in surgical patients

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    Absolute or functional iron deficiency is the most prevalent cause of anaemia in surgical patients, and its correction is a fundamental strategy within "Patient Blood Management" programmes. Offering perioperative oral iron for treating iron deficiency anaemia is still recommended, but intravenous iron has been demonstrated to be superior in most cases. However, the long-standing prejudice against intravenous iron administration, which is thought to induce anaphylaxis, hypotension and shock, still persists. With currently available intravenous iron formulations, minor infusion reactions are not common. These self-limited reactions are due to labile iron and not hypersensitivity. Aggressively treating infusion reactions with H 1 -antihistamines or vasopressors should be avoided. Self-limited hypotension during intravenous iron infusion could be considered to be due to hypersensitivity or vascular reaction to labile iron. Acute hypersensitivity reactions to current intravenous iron formulation are believed to be caused by complement activation-related pseudo-allergy. However, though exceedingly rare (<1:250,000 administrations), they should not be ignored, and intravenous iron should be administered only at facilities where staff is trained to evaluate and manage these reactions. As preventive measures, prior to the infusion, staff should inform all patients about infusion reactions and identify those patients with increased risk of hypersensitivity or contraindications for intravenous iron. Infusion should be started at a low rate for a few minutes. In the event of a reaction, the very first intervention should be the immediate cessation of the infusion, followed by evaluation of severity and treatment. An algorithm to scale the intensity of treatment to the clinical picture and/or response to therapy is presented

    Universal Scaling of Ballistic Magnetoresistance in Magnetic Nanocontacts

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    We show that ballistic magnetoresistance exhibits universal scaling in atomic or nanometer scale contacts. Plotting the data as conductance, we find that, if the maximum magnetoconductance is normalized to unity and the conductance is scaled with the conductivity of the bulk material, the data fall in a narrow region, independent of the nanocontact materials, for our four data sets and four from the literature. The results agree with a theory that takes into account spin-scattering within a magneticdomain wall

    Along-strike segmentation in the northern Caribbean plate boundary zone (Hispaniola sector): Tectonic implications

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    Highlights • Along-strike variations of tectonic framework in northeastern Caribbean margin are studied. • Shallow plate boundary structure related to the slab geometry has been defined. • First-order fault systems and its associated features have been mapped along the margin. Abstract The North American (NOAM) plate converges with the Caribbean (CARIB) plate at a rate of 20.0 ± 0.4 mm/yr. towards 254 ± 1°. Plate convergence is highly oblique (20–10°), resulting in a complex crustal boundary with along-strike segmentation, strain partitioning and microplate tectonics. We study the oblique convergence of the NOAM and CARIB plates between southeastern Cuba to northern Puerto Rico using new swath multibeam bathymetry data and 2D multi-channel seismic profiles. The combined interpretation of marine geophysical data with the seismicity and geodetic data from public databases allow us to perform a regional scale analysis of the shallower structure, the seismotectonics and the slab geometry along the plate boundary. Due to differential rollback between the NOAM oceanic crust north of Puerto Rico and the relative thicker Bahamas Carbonate Province crust north of Hispaniola a slab tear is created at 68.5°W. The northern margin of Puerto Rico records the oblique high-dip subduction and rollback of the NOAM plate below the island arc. Those processes have resulted in a forearc transpressive tectonics (without strain partitioning), controlled by the Septentrional-Oriente Fault Zone (SOFZ) and the Bunce Fault Zone (BFZ). Meanwhile, in the northern margin of Hispaniola, the collision of the Bahamas Carbonate Province results in high plate coupling with strain partitioning: SOFZ and Northern Hispaniola Deformed Belt (NHDB). In the northern Haitian margin, compression is still relevant since seismicity is mostly associated with the deformation front, whereas strike slip earthquakes are hardly anecdotal. Although in Hispaniola intermediate-depth seismicity should disappear, diffuse intermediate-depth hypocenter remains evidencing the presence of remnant NOAM subducted slab below central and western Hispaniola. Results of this study improve our understanding of the active tectonics in the NE Caribbean that it is the base for future assessment studies on seismic and tsunamigenic hazard

    Pericyte FAK negatively regulates Gas6/Axl signalling to suppress tumour angiogenesis and tumour growth

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    The overexpression of the protein tyrosine kinase, Focal adhesion kinase (FAK), in endothelial cells has implicated its requirement in angiogenesis and tumour growth, but how pericyte FAK regulates tumour angiogenesis is unknown. We show that pericyte FAK regulates tumour growth and angiogenesis in multiple mouse models of melanoma, lung carcinoma and pancreatic B-cell insulinoma and provide evidence that loss of pericyte FAK enhances Gas6-stimulated phosphorylation of the receptor tyrosine kinase, Axl with an upregulation of Cyr61, driving enhanced tumour growth. We further show that pericyte derived Cyr61 instructs tumour cells to elevate expression of the proangiogenic/protumourigenic transmembrane receptor Tissue Factor. Finally, in human melanoma we show that when 50% or more tumour blood vessels are pericyte-FAK negative, melanoma patients are stratified into those with increased tumour size, enhanced blood vessel density and metastasis. Overall our data uncover a previously unknown mechanism of tumour growth by pericytes that is controlled by pericyte FAK

    High-Risk Cervical Human Papillomavirus Infections among Human Immunodeficiency Virus-Positive Women in the Bahamas

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    Background\ud \ud High-risk (HR) HPV genotypes other than 16 and 18 have been detected in a significant proportion of immunocompromised females. We aim to evaluate the frequency of HR HPV genotypes in a population of HIV-positive Caribbean women.\ud Methods\ud \ud One hundred sixty-seven consecutive, non-pregnant, HIV-positive females ≥18 years were recruited in this study. Each participant received a vaginal examination, PAP smear, and completed a questionnaire. DNA was extracted for HPV testing in 86 patients.\ud Results\ud \ud Mean age was 39.1 years for women positive for HR HPV and 43.1 years for women negative for HR HPV (P value = 0.040). 78% (130/167) of the women had HR HPV infections; the prevalence of abnormal cervical cytology was 38% among women who were HR HPV-positive compared to women who were HR HPV-negative (22%). Fifty-one percent of the 86 women with available genotype carried infections with HPV 16 and/or HPV 18; genotypes of unknown risk were also frequently observed. Women who had a CD4+ count of ≤200 had 7 times increased odds of carrying HR HPV infection in comparison to women with CD4+>200.\ud Conclusions\ud \ud HR HPV infections in HIV infected females may consist of more than just HPV 16 and 18, but also HPV 52 and 58. Further studies are needed to determine whether HPV 52 and 58 play a significant role in the development of cervical cytological abnormalities in HIV+ women

    Leucemia mieloide crónica en paciente pediátrico. Experiencia en nuestro centro

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    PB-080 Introducción: La Leucemia Mieloide Crónica (LMC) constituye una patología rara en niños constituyendo el 2% de todas las leucemias diagnosticadas en niños menores de 15 años. La presentación clínica suele ser más agresiva que en adultos y la proporción de pacientes con LMC en fase acelerada o blástica es mayor que para pacientes de edad más avanzada. La cifra media de leucocitos al diagnóstico se encuentra en 250 x 109/L, mientras que en adultos es de 80x109/L - 150x109/L. El 90- 95% de los niños con características clínicas y morfológicas de LMC tienen cromosoma Philadelphia positivo. El manejo de la enfermedad se basa en la presentación, la fase en la que se encuentre y los niveles de respuesta al tratamiento. Material y métodos: Estudio descriptivo y retrospectivo en el que se han analizado las características clínicas, de laboratorio y la respuesta al tratamiento de los pacientes pediátricos diagnosticados de LMC en los últimos 10 años en nuestro hospital (hospital de tercer nivel y de referencia de la CCAA de Aragón). Resultados: Uno de ellos no realizó ningún tipo de respuesta al Imatinib con aumento de las copias de BCR/ABL por Biología Molecular a pesar de buenos niveles de Imatinib, por lo que se inició tratamiento con Dasatinib en marzo de 2018, alcanzando en la última reevaluación a los a los 12 meses respuesta citogenética pero sin alcanzar ningún tipo de respuesta molecular. Conclusiones: Como se describe en la literatura, ambos pacientes ..

    Scaling Tests of the Cross Section for Deeply Virtual Compton Scattering

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    We present the first measurements of the \vec{e}p->epg cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q^2 dependence (from 1.5 to 2.3 GeV^2) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q^2. The helicity-independent cross section is also measured at Q^2=2.3 GeV^2. We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.Comment: 5 pages, 4 figures, 2 tables. Text shortened for publication. References added. One figure remove
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