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There is much debate on the use of angiotensin receptor blockers (ARBs) in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-infected patients. Although it has been suggested that ARBs might lead to a higher susceptibility and severity of SARS-CoV-2 infection, experimental data suggest that ARBs may reduce acute lung injury via blocking angiotensin-II-mediated pulmonary permeability, inflammation, and fibrosis. However, despite these hypotheses, specific studies on ARBs in SARS-CoV-2 patients are lacking. METHODS: The PRAETORIAN-COVID trial is a multicenter, double-blind, placebo-controlled 1:1 randomized clinical trial in adult hospitalized SARS-CoV-2-infected patients (n = 651). The primary aim is to investigate the effect of the ARB valsartan compared to placebo on the composite end point of admission to an intensive care unit, mechanical ventilation, or death within 14 days of randomization. The active-treatment arm will receive valsartan in a dosage titrated to blood pressure up to a maximum of 160 mg bid, and the placebo arm will receive matching placebo. Treatment duration will be 14 days, or until the occurrence of the primary end point or until hospital discharge, if either of these occurs within 14 days. The trial is registered at clinicaltrials.gov (NCT04335786, 2020). SUMMARY: The PRAETORIAN-COVID trial is a double-blind, placebo-controlled 1:1 randomized trial to assess the effect of valsartan compared to placebo on the occurrence of ICU admission, mechanical ventilation, and death in hospitalized SARS-CoV-2-infected patients. The results of this study might impact the treatment of SARS-CoV-2 patients globally.
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Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Betacoronavirus , Unidades de Cuidados Coronarios , Infecciones por Coronavirus/complicaciones , Neumonía Viral/complicaciones , Ensayos Clínicos Controlados Aleatorios como Asunto , Síndrome de Dificultad Respiratoria/prevención & control , Valsartán/uso terapéutico , Adulto , Bloqueadores del Receptor Tipo 1 de Angiotensina II/administración & dosificación , COVID-19 , Infecciones por Coronavirus/mortalidad , Método Doble Ciego , Esquema de Medicación , Humanos , Pacientes Internos , Estudios Multicéntricos como Asunto , Países Bajos , Pandemias , Placebos/uso terapéutico , Neumonía Viral/mortalidad , Respiración Artificial , Síndrome de Dificultad Respiratoria/mortalidad , SARS-CoV-2 , Factores de Tiempo , Valsartán/administración & dosificaciónRESUMEN
BACKGROUND: Screening for specific IgE against 2S albumin proteins Ara h 2 and 6 has good positive predictive value in diagnosing peanut allergy. From the third 2S member Ara h 7, 3 isoforms have been identified. Their allergenicity has not been elucidated. OBJECTIVE: This study investigated the allergenicity of Ara h 7 isoforms compared to Ara h 2 and 6. METHODS: Sensitization of 15 DBPCFC-confirmed peanut-allergic patients to recombinant Ara h 2.0201, Ara h 6.01 and isoforms of recombinant Ara h 7 was determined by IgE immunoblotting strips. A basophil activation test (BAT) was performed in 9 patients to determine IgE-cross-linking capacities of the allergens. Sensitivity to the allergens was tested in 5 patients who were sensitized to at least 1 Ara h 7 isoform, by a concentration range in the BAT. 3D prediction models and sequence alignments were used to visualize differences between isoforms and to predict allergenic epitope regions. RESULTS: Sensitization to Ara h 7.0201 was most frequent (80%) and showed to be equally potent as Ara h 2.0201 and 6.01 in inducing basophil degranulation. Sensitization to Ara h 7.0201 together with Ara h 2.0201 and/or 6.01 was observed, indicating the presence of unique epitopes compared to the other 2 isoforms. Differences between the 3 Ara h 7 isoforms were observed in C-terminal cysteine residues, pepsin and trypsin cleavage sites and 3 single amino acid substitutions. CONCLUSION & CLINICAL RELEVANCE: The majority of peanut-allergic patients are sensitized to isoform Ara h 7.0201, which is functionally as active as Ara h 2.0201 and 6.01. Unique epitopes are most likely located in the C-terminus or an allergenic loop region which is a known allergenic epitope region for Ara h 2.0201 and 6.01. Due to its unique epitopes and allergenicity, it is an interesting candidate to improve the diagnostic accuracy for peanut allergy.
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Albuminas 2S de Plantas/inmunología , Antígenos de Plantas/inmunología , Basófilos/inmunología , Degranulación de la Célula/inmunología , Epítopos/inmunología , Hipersensibilidad al Cacahuete/inmunología , Albuminas 2S de Plantas/química , Adulto , Secuencia de Aminoácidos , Antígenos de Plantas/química , Basófilos/metabolismo , Epítopos/química , Femenino , Humanos , Inmunoglobulina E/inmunología , Masculino , Persona de Mediana Edad , Modelos Moleculares , Hipersensibilidad al Cacahuete/diagnóstico , Conformación Proteica , Isoformas de Proteínas , Relación Estructura-ActividadRESUMEN
BACKGROUND: The role of sensitization to commercially available allergens of English walnut (Juglans regia) Jug r 1, 2 and 3 in walnut allergy has been previously investigated in walnut allergic adults and was unable to explain all cases of walnut allergy. OBJECTIVES: Identify recognized walnut allergens, other than the ones previously investigated (Jug r 1-3), in walnut allergic adults and determine the sensitization frequency and diagnostic value. METHODS: Three different in-house walnut extracts were prepared and analysed on SDS-PAGE blots to identify allergenic walnut proteins. Immunoblots and immunoprecipitation, followed by LC-MS analysis, were performed to screen for, and confirm, IgE binding to walnut allergens in selected walnut allergic adults. In a cohort of 55 walnut challenged adults, including 33 allergic and 22 tolerant, sensitization to native and recombinant walnut allergen Jug r 4 was assessed using immunoblotting and immuno-line blot (EUROLINE), respectively. RESULTS: Screening of sera of 8 walnut allergic adults identified Jug r 4 as an allergen in our population. In the total cohort of 55 subjects, 5 were positive for Jug r 4 on immunoblot and 10 on EUROLINE. All but one EUROLINE positive subject had a positive food challenge (sensitivity 27%, specificity 95%, PPV 90%, NPV 47%). All 5 subjects positive on immunoblot were also positive on EUROLINE. LC-MS analysis showed a lack of Jug r 4 in the ImmunoCAP extract. Co-sensitization to other 11S albumins (eg hazelnut Cor a 9) was common in Jug r 4 sensitized subjects, potentially due to cross-reactivity. CONCLUSIONS: Walnut 11S globulin Jug r 4 is a relevant minor allergen, recognized by 27% of walnut allergic adults. It has a high positive predictive value of 90% for walnut allergy. Specific IgE against Jug r 4 occurred mostly with concomitant sensitization to other walnut components, mainly Jug r 1.
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Antígenos de Plantas/inmunología , Juglans/efectos adversos , Hipersensibilidad a la Nuez/inmunología , Proteínas de Plantas/inmunología , Adulto , Antígenos de Plantas/química , Antígenos de Plantas/aislamiento & purificación , Cromatografía Liquida , Reacciones Cruzadas/inmunología , Femenino , Humanos , Inmunoensayo , Inmunoglobulina E/inmunología , Juglans/química , Masculino , Espectrometría de Masas , Hipersensibilidad a la Nuez/diagnóstico , Extractos Vegetales/química , Extractos Vegetales/inmunología , Proteínas de Plantas/química , Proteínas de Plantas/aislamiento & purificación , Sensibilidad y Especificidad , Pruebas Cutáneas , Adulto JovenRESUMEN
Predicting and managing the difficult airway is a lifesaving and vital basic task for the anesthetist. Current guidelines of all important societies include thyromental distance (TMD, "Patil") as a possible predictor for a difficult airway and includes two important aspects for airway management: the mandibular space and the flexibility of the cervical spine. We evaluated knowledge and execution regarding TMD for predicting a difficult airway on participants at the Euroanaesthesia (ESA) congress and German Anaesthesia Congress (DAC) in 2014. Our evaluation consisted of a theoretical part with questions regarding general knowledge and a practical evaluation with anesthetists performing on a human airway model. Practical evaluations were performed separately from other participants. During the DAC 245 (ESA 230) physicians participated, of which 64% were male (ESA 58%). At the DAC 182 (74.3%) and ESA 82 (35.6%) participants knew about Patil/TMD. Its use as a predictive score for a difficult airway was known by 122 (49.8%; DAC) and 79 (34.4%; ESA) participants. The correct definition for intubation was given by 45 (25.7%) at the DAC and 56 (24.3%) at ESA. Only 40-41% of the participants measured the correct distance for TMD. Only 6.1-6.5% completed both the theoretical and practical parts correctly. As non-invasive TMD includes two different aspects of patient airways and is part of current guidelines, education and training must be extended to assure adequate evaluation in the future.
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Manejo de la Vía Aérea/métodos , Anestesiólogos , Conocimientos, Actitudes y Práctica en Salud , Mandíbula/anatomía & histología , Glándula Tiroides/anatomía & histología , Adulto , Competencia Clínica , Europa (Continente) , Femenino , Humanos , Intubación Intratraqueal/métodos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
In 1985 Mallampati et al. published a non-invasive score for the evaluation of airways (Mallampati grading scale, MGS), which originally consisted of only three different classes and has been modified several times. At present it is mostly used in the version of Samsoon and Young consisting of four different classes. Class I: soft palate, fauces, uvula, palatopharyngeal arch visible, class II: soft palate, fauces, uvula visible, class III: soft palate, base of the uvula visible and class IV: soft palate not visible. Nevertheless, other versions of MGS still exist, each having different values for sensitivity and specification. The current opinion is therefore that MGS is no longer useful as a stand-alone predictor but in combination with others it is still part of today's most relevant guidelines, such as those of the American Society of Anesthesiologists (ASA), the UK's Difficult Airway Society (DAS), the European Society of Anaesthesiology (ESA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) and must therefore be known by anesthetists. Even in times of sophisticated tools for airway management, the procedure remains a high risk, so every anesthetist has to be prepared for and well trained in management of known and unexpected difficult airways. Evaluation of the patient's airway is a part of modern airway management to prevent problems and reduce risk of hypoxia during the procedure. The theoretical knowledge and practical skills of European anesthetists were evaluated at two international congresses, the German Anesthesia Congress (DAC) and Euroanaesthesia 2014. The DAC is an annual meeting of German speaking anesthetists, hosted by the DGAI. The Euroanaesthesia is the annual European pendant hosted by the ESA. Participation was voluntary and only physicians were allowed to take part. Theory was evaluated by a questionnaire containing open and closed questions for MGS that had to be answered by every participant alone. Apart from theory, a practical evaluation was performed. Every participant had to classify the MGS of a human airway model. The model was identical on both congresses. According to the original publication a checklist containing the factors essential for the correct performance was filled out by a supervising experienced anesthetist. During DAC 2014 nâ¯= 267 physicians participated in the study, 22 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part. A total of 245 data sets were evaluated. During Euroanaesthesia 2014 nâ¯= 298 physicians participated in the study, 68 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part and 230 data sets were evaluated. At the DAC the mean age (± SD) was 44.5⯱ 9.5 years, 157 (64.1%) were male and 88 (35.9%) were female. Working experience was trainee anesthetist in 16.7% and other participants were experienced anesthetists. At the ESA the mean age (± SD) was 42.4⯱ 9.5 years, 133 (57.8%) were male and 97 (42.2%) female. Trainee anesthetists were 15.2%, the rest were experienced anesthetists. The DAC participants knew Mallampati classes 1 (65%) and 4 (45%) better than 2 and 3 and there was no relevant differences to the ESA (close to 30% knew the classes 1-4 here). Classification of the airway model was correct in 62% and 67% at DAC and ESA, respectively. Most participants performed the practical evaluation correctly except the sitting position of the model. In agreement with earlier studies, these results show the lack of knowledge in evaluation of airways according to current guidelines of all relevant societies. This is likely to increase preventable risks for patients as unexpected difficult airway management increases the risk for hypoxia and intubation damage.
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Manejo de la Vía Aérea , Anestesiología/educación , Anestesia/métodos , Cuidados Críticos , Educación Médica , Humanos , Médicos , Encuestas y CuestionariosRESUMEN
AIMS: Mesenchymal stem cells (MSC) have recently attracted interest as a potential basis for a cell-based therapy of AD. We investigated the putative immune-modulatory effects in neuroinflammation of systemic transplantation of MSC into APP/PS1 transgenic mice. METHODS: 106 MSC were injected into APP/PS1 mice via the tail vein and histological analysis was performed for microglia and amyloid (pE3-Aß) plaque numbers, glial distribution and pE3-Aß plaque size. In addition, a biochemical analysis by qPCR for pro-inflammatory, chemoattractant and neurotrophic factors was performed. RESULTS: MSC are associated with pE3-Aß plaques. The effects of transplantation on microglia-associated pathology could be observed after 28 days. Animals showed a reduction in microglial numbers in the cortex and in microglia size. Gene expression was reduced for TNF-α, IL-6, MCP-1, and for NGF, in MSC recipients. Also, we investigated for the first time and found no changes in expression of IL-10, CCR5, BDNF, VEGF and IFNγ. PTGER2 expression levels were increased in the hippocampus but were reduced in the cortex of MSC recipients. While there were no transplant-related changes in pE3-Aß plaque numbers, a reduction in the size of pE3-Aß plaques was observed in the hippocampus of transplant recipients. CONCLUSION: This is the first study to show reduction in pE3-Aß plaque size. pE3-Aß plaques have gained attention as potential key participants in AD due to their increased aggregation propensity, the possibility for the initial seeding event, resistance against degradation and neurotoxicity. These findings support the hypothesis that MSC-transplants may affect AD pathology via an immune-modulatory function that includes an effect on microglial cells.
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Enfermedad de Alzheimer/patología , Encéfalo/patología , Trasplante de Células Madre Mesenquimatosas/métodos , Placa Amiloide/patología , Animales , Ratones , Ratones TransgénicosRESUMEN
BACKGROUND: Patients with obstructive jaundice due to periampullary tumours may undergo preoperative biliary drainage (PBD). The effect of PBD on the microbiome of the biliary system and on postoperative outcome remains unclear. METHODS: A single-centre retrospective study of patients with obstructive jaundice due to periampullary cancer, treated between July 2007 and July 2015, was undertaken. Intraoperative bile samples were obtained for microbiological analysis after transection of the common bile duct. Postoperative complications were registered. RESULTS: Of 290 patients treated, intraoperative bile samples were present for 172 patients (59·3 per cent) who had PBD and 118 (40·7 per cent) who did not. Contamination of bile was increased significantly in patients who underwent stenting (97·1 per cent versus 18·6 per cent in those without stenting; P < 0·001). PBD resulted in a shift in the biliary microbiome from Escherichia coli in non-stented patients (45 per cent versus 19·2 per cent in stented patients; P = 0·009) towards increased contamination with Enterococcus faecalis (9 versus 37·7 per cent respectively; P = 0·008) and Enterobacter cloacae (0 versus 20·4 per cent; P = 0·033). This shift was associated with a high incidence of bacterial resistance against ampicillin-sulbactam (63·6 per cent versus 18 per cent in patients with no PBD; P < 0·001), piperacillin-tazobactam (30·1 versus 0 per cent respectively; P = 0·003), ciprofloxacin (28·5 versus 5 per cent; P = 0·047) and imipenem (26·6 versus 0 per cent; P = 0·011). The rate of wound infection was higher in patients with a positive bile culture (21·0 per cent versus 6 per cent in patients with sterile bile; P = 0·002). Regression analysis revealed the presence of Enterococcus faecium (odds ratio 2·83, 95 per cent c.i. 1·17 to 6·84; P = 0·021) and Citrobacter species (odds ratio 5·09, 1·65 to 15·71; P = 0·005) as independent risk factors for postoperative wound infection. CONCLUSION: There are fundamental differences in the biliary microbiome of patients with periampullary cancer who undergo PBD and those who do not. PBD induces a shift of the biliary microbiome towards a more aggressive and resistant spectrum, which requires a differentiated perioperative antibiotic treatment strategy.
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Bilis/microbiología , Neoplasias del Conducto Colédoco/complicaciones , Drenaje , Ictericia Obstructiva/terapia , Microbiota , Cuidados Preoperatorios , Anciano , Ampolla Hepatopancreática/cirugía , Antibacterianos/uso terapéutico , Colangitis/epidemiología , Citrobacter/aislamiento & purificación , Neoplasias del Conducto Colédoco/cirugía , Farmacorresistencia Bacteriana Múltiple , Infecciones por Enterobacteriaceae/epidemiología , Enterococcus faecalis/aislamiento & purificación , Femenino , Alemania/epidemiología , Infecciones por Bacterias Grampositivas/epidemiología , Humanos , Ictericia Obstructiva/etiología , Masculino , Análisis de Regresión , Estudios Retrospectivos , Factores de Riesgo , Stents , Infección de la Herida Quirúrgica/epidemiologíaRESUMEN
We report the first longitudinal-transverse separation of the deeply virtual exclusive π^{0} electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσ_{L}/dt, dσ_{T}/dt, dσ_{LT}/dt, and dσ_{TT}/dt are extracted as a function of the momentum transfer to the recoil system at Q^{2}=1.75 GeV^{2} and x_{B}=0.36. The edâedπ^{0} cross sections are found compatible with the small values expected from theoretical models. The enâenπ^{0} cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity generalized parton distributions of the nucleon. By combining these results with previous measurements of π^{0} electroproduction off the proton, we present a flavor decomposition of the u and d quark contributions to the cross section.
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The oncogene DJ-1 has been originally identified as a suppressor of PTEN. Further on, loss-of-function mutations have been described as a causative factor in Parkinson's disease (PD). DJ-1 has an important function in cellular antioxidant responses, but its role in central metabolism of neurons is still elusive. We applied stable isotope assisted metabolic profiling to investigate the effect of a functional loss of DJ-1 and show that DJ-1 deficient neuronal cells exhibit decreased glutamine influx and reduced serine biosynthesis. By providing precursors for GSH synthesis, these two metabolic pathways are important contributors to cellular antioxidant response. Down-regulation of these pathways, as a result of loss of DJ-1 leads to an impaired antioxidant response. Furthermore, DJ-1 deficient mouse microglia showed a weak but constitutive pro-inflammatory activation. The combined effects of altered central metabolism and constitutive activation of glia cells raise the susceptibility of dopaminergic neurons towards degeneration in patients harboring mutated DJ-1. Our work reveals metabolic alterations leading to increased cellular instability and identifies potential new intervention points that can further be studied in the light of novel translational medicine approaches.
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Antioxidantes/metabolismo , Glutamina/metabolismo , Neuronas/metabolismo , Proteína Desglicasa DJ-1/metabolismo , Serina/metabolismo , Animales , Células Cultivadas , Humanos , Metaboloma , Ratones , Microglía/metabolismo , Mitocondrias/metabolismo , Estrés Oxidativo , Proteína Desglicasa DJ-1/genéticaRESUMEN
We present deeply virtual π^{0} electroproduction cross-section measurements at x_{B}=0.36 and three different Q^{2} values ranging from 1.5 to 2 GeV^{2}, obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σ_{LT}. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q^{2} regime.
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29Si{27Al} TRAPDOR MAS NMR was applied to two faujasite-type zeolites with Si/Al ratios of 1.3 (Na-X) and 2.7 (Na-Y). The aim of this test study is to show that different Q4(mAl) sites (m =4, 3, 2, 1) can be distinguished by differently strong TRAPDOR effects (ΔS/S0). Indeed, it was found that the TRAPDOR effect depends on the number m of AlO4 units connected to the Q4 silicon tetrahedrons. For Na-X, the measured ΔS/S0 values are 1 : 0.81 : 0.56 for Q4(4Al), Q4(3Al) and Q4(2Al), respectively (normalized to Q4(4Al)). The corresponding ΔS/S0 values are the same for Na-Y within the error bars, although the silicon sites are different: Q4(3Al), Q4(2Al) and Q4(1Al) and now normalized to Q4(3Al) as no Q4(4Al) is present. Nevertheless, the proposed method opens up the possibility to distinguish overlapping 29Si NMR signals of the Qn(mAl) sites in amorphous materials as the main goal of these investigations.
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The perineuronal net (PN) is a subtype of extracellular matrix appearing as a net-like structure around distinct neurons throughout the whole CNS. PNs surround the soma, proximal dendrites, and the axonal initial segment embedding synaptic terminals on the neuronal surface. Different functions of the PNs are suggested which include support of synaptic stabilization, inhibition of axonal sprouting, and control of neuronal plasticity. A number of studies provide evidence that removing PNs or PN-components results in renewed neurite growth and synaptogenesis. In a mouse model for Purkinje cell degeneration, we examined the effect of deafferentation on synaptic remodeling and modulation of PNs in the deep cerebellar nuclei. We found reduced GABAergic, enhanced glutamatergic innervations at PN-associated neurons, and altered expression of the PN-components brevican and hapln4. These data refer to a direct interaction between ECM and synapses. The altered brevican expression induced by activated astrocytes could be required for an adequate regeneration by promoting neurite growth and synaptogenesis.
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Núcleos Cerebelosos/fisiopatología , Degeneración Nerviosa/fisiopatología , Red Nerviosa/fisiopatología , Plasticidad Neuronal/fisiología , Células de Purkinje/patología , Sinapsis/fisiología , Animales , Núcleos Cerebelosos/patología , Modelos Animales de Enfermedad , Ratones , Degeneración Nerviosa/patología , Red Nerviosa/patología , Sinapsis/patologíaRESUMEN
BACKGROUND: Venous thromboembolism (VTE) is a complex and serious condition, with high morbidity and mortality, especially in hospitalised patients. Yet its diagnosis remains challenging because of its unspecific clinical presentation. The objective of this study was to apply an algorithmic combination approach to diagnosing VTE by the addition of a D-dimer assay and Wells' criteria for our hospital's internal referral forms requesting compression ultrasound (CUS), to determine the effect on the number of referrals for CUS and the incidence of deep vein thrombosis (DVT) diagnoses. METHOD: Inpatients who had been referred to the hospital's vascular laboratory and who had undergone a CUS to exclude an acute lower limb DVT were retrospectively analysed between January 2009 and December 2013, and compared to prospectively collected data for the full year (2014) after the introduction of the new referral form. Comparisons included the mean annual number of referrals for CUS and the incidence of DVT diagnoses. RESULTS: The hospital incidence of diagnosed DVTs for 2009-2013 was 0.17%, compared to 0.16% for 2014 (ρ = 0.930). In contrast, the total number of referrals for CUS as a percentage of all hospital admissions dropped from 0.84% in 2009-2013 to 0.63% in 2014 (ρ = 0.009, odds ratio 0.76, 95% confidence interval: 0.62-0.93). CONCLUSION: The implementation of Wells' criteria and D-dimer to the new request form for CUS significantly decreased referrals to the hospital's vascular laboratory without impacting on the number of DVT cases diagnosed. This is a positive change which simplifies care and reduces the expense of ultrasonography investigations.
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New results are reported from a measurement of π^{0} electroproduction near threshold using the p(e,e^{'}p)π^{0} reaction. The experiment was designed to determine precisely the energy dependence of s- and p-wave electromagnetic multipoles as a stringent test of the predictions of chiral perturbation theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the Ï_{π}^{*} and θ_{π}^{*} angles in the pπ^{0} center of mass was obtained for invariant energies above threshold from 0.5 up to 15 MeV. The 4-momentum transfer Q^{2} coverage ranges from 0.05 to 0.155 (GeV/c)^{2} in fine steps. A simple phenomenological analysis of our data shows strong disagreement with p-wave predictions from ChPT for Q^{2}>0.07 (GeV/c)^{2}, while the s-wave predictions are in reasonable agreement.
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Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
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We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97 GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97 GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.
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BACKGROUND: Specific immunotherapy for peanut allergy is associated with significant side-effects. Chemically modified allergens may provide a safer alternative. OBJECTIVE: This study aimed to analyse the immunogenicity and allergenicity of modified peanut conglutin. METHODS: Native peanut conglutin and two modifications thereof were generated (RA and RAGA). Conglutin-specific T cell lines from 11 peanut-allergic patients were analysed for proliferation and cytokine production. Sera from 14 patients were analysed for IgE/IgG1/IgG4 binding by immunoblot and ELISA. IgE reactivity was analysed by direct and indirect basophil activation test (BAT), in presence and absence of patient plasma or CD32-blocking antibodies. RESULTS: T cell proliferation to RA was unchanged, and proliferation to RAGA was reduced compared to native conglutin. Cytokine profiles remained unchanged. IgE, IgG1 and IgG4 binding to RA and RAGA was significantly reduced. In the direct BAT, the relative potency of modified conglutin was decreased in 67% and increased/similar in 33% of the patients. In the indirect BAT, RA and RAGA were 10-100 times less potent than native conglutin. Addition of plasma to the indirect BAT increased the relative potency of modified conglutin in patients with high peanut-specific IgG levels. This was mediated via blocking of the response to native conglutin, most likely by soluble IgG, and not via CD32. CONCLUSION AND CLINICAL RELEVANCE: Chemical modification of peanut conglutin by RA retains immunogenicity and reduces allergenicity and may be a promising approach for development of a curative treatment for peanut allergy. In a subgroup of patients, where the reactivity of native conglutin is already partially blocked by IgG, the effect of the modification of conglutin is less pronounced.
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Arachis/efectos adversos , Inmunoglobulina E/inmunología , Hipersensibilidad al Cacahuete/inmunología , Proteínas de Plantas/inmunología , Subgrupos de Linfocitos T/inmunología , Anticuerpos/sangre , Anticuerpos/inmunología , Anticuerpos Bloqueadores/sangre , Anticuerpos Bloqueadores/inmunología , Basófilos/inmunología , Citocinas/metabolismo , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Activación de Linfocitos/inmunología , Hipersensibilidad al Cacahuete/sangre , Hipersensibilidad al Cacahuete/diagnóstico , Proteínas de Plantas/química , Receptores de IgG/antagonistas & inhibidores , Receptores de IgG/metabolismo , Subgrupos de Linfocitos T/metabolismoRESUMEN
BACKGROUND: Several studies investigated whether hydrolysed proteins can induce tolerance to cow's milk (CM) in children at risk of developing CM allergy. Due to methodological problems and inconsistent findings, the evidence for a tolerogenic effect is limited. A major problem is that different hydrolysates may give different outcomes due to variations in their production and composition. OBJECTIVE: The aim of the study was to investigate the effect of the degree of hydrolysis on the allergenicity and immunogenicity of whey hydrolysates. METHODS: The hydrolysis of whey was stopped at different time-points between 1 and 60 min. In 18 CM allergic patients, the allergenicity of the hydrolysates was determined by immunoblot and the basophil activation test. To test immunogenicity, CM-specific T cell lines were generated. RESULTS: In most patients, increasing time of hydrolysis decreased IgE recognition and basophil activation. However, in five patients, hydrolysed proteins induced more basophil activation than non-hydrolysed proteins. The immunoblot data indicated that these patients recognized either a 25- to 30-kDa degradation product of casein or a 10-kDa degradation product of whey. Although T cell activation was decreased in all patients over time, half of them still showed a positive response to the proteins after 60 min of hydrolysis. CONCLUSION: Increasing the time of hydrolysis reduces both allergenicity and immunogenicity of whey hydrolysates in most but not all patients. This indicates that not the degree of hydrolysis is decisive but the presence and stability of IgE and T cell epitopes in the hydrolysate recognized by individual patients.
Asunto(s)
Basófilos/inmunología , Hipersensibilidad a la Leche/inmunología , Hipersensibilidad a la Leche/metabolismo , Proteínas de la Leche/metabolismo , Leche/efectos adversos , Linfocitos T/inmunología , Adulto , Animales , Bovinos , Femenino , Humanos , Hidrólisis , Inmunoglobulina E/inmunología , Inmunoglobulina E/metabolismo , Activación de Linfocitos/inmunología , Masculino , Persona de Mediana Edad , Proteínas de la Leche/inmunología , Péptidos/inmunología , Péptidos/metabolismo , Unión Proteica/inmunología , Hidrolisados de Proteína/inmunología , Hidrolisados de Proteína/metabolismo , Proteína de Suero de Leche , Adulto JovenRESUMEN
We present a precise measurement of double-polarization asymmetries in the ^{3}He[over â](e[over â],e^{'}d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ^{3}He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q^{2}=0.25(GeV/c)^{2} for missing momenta up to 270 MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_{m} and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.
RESUMEN
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.