Masse et oscillations des neutrinos

École thématiqu

Platelet-activating factor acetylhydrolase and haemophagocytosis in the sepsis syndrome.

Sepsis syndrome (SS) is associated with depressed PAF acetylhydrolase, the enzyme responsible for the degradation of platelet activating factor. PAF acetylhydrolase is in a large part produced by macrophages, whose inadequate activation with haemophagocytosis is frequent in patients with SS. The aim of this study was to test the hypothesis that PAF acetylhydrolase levels could be affected in these critically ill patients, because of the large amounts produced by activated macrophages in vitro and in vivo in animal models. The levels of serum PAF acetylhydrolase were assessed in 90 SS patients, who were divided into three groups: patients with (n = 34) or without haemophagocytosis (n = 31), and patients without thrombocytopenia (n = 25) who were used as a control group. The number of organ dysfunctions was matched between patients with haemophagocytosis and controls. Normal reference values were obtained in 59 randomly selected blood donors. Circulating levels of PAF acetylhydrolase were significantly (p = 0.0001) decreased in patients with SS (57+/-3 nmol/ml/min, n = 90) when compared with healthy subjects (69+/-3 nmol/ml/min, n = 59). PAF acetylhydrolase levels were greater in the presence of a haemophagocytosis but without statistical significance (64.2+/-6.5 vs. 50.1+/-2.8:p = 0.25). Despite the fact that macrophagic activation stimulates the in vitro release of PAF acetylhydrolase, no difference was found between patients with or without haemophagocytosis. The mechanism and the role of the PAF acetylhydrolase reduction in SS patients remain to be determined

Training in critical care echocardiography

Echocardiography is useful for the diagnosis and management of hemodynamic failure in the intensive care unit so that competence in some elements of echocardiography is a core skill of the critical care specialist. An important issue is how to provide training to intensivists so that they are competent in the field. This article will review issues related to training in critical care echocardiography

Derivation of transient relativistic fluid dynamics from the Boltzmann equation

In this work we present a general derivation of relativistic fluid dynamics from the Boltzmann equation using the method of moments. The main difference between our approach and the traditional 14-moment approximation is that we will not close the fluid-dynamical equations of motion by truncating the expansion of the distribution function. Instead, we keep all terms in the moment expansion. The reduction of the degrees of freedom is done by identifying the microscopic time scales of the Boltzmann equation and considering only the slowest ones. In addition, the equations of motion for the dissipative quantities are truncated according to a systematic power-counting scheme in Knudsen and inverse Reynolds number. We conclude that the equations of motion can be closed in terms of only 14 dynamical variables, as long as we only keep terms of second order in Knudsen and/or inverse Reynolds number. We show that, even though the equations of motion are closed in terms of these 14 fields, the transport coefficients carry information about all the moments of the distribution function. In this way, we can show that the particle-diffusion and shear-viscosity coefficients agree with the values given by the Chapman-Enskog expansion.Comment: 27 page

SEARCH FOR NEUTRINO OSCILLATION AT BUGEY

The high flux of low energy [MATH]e produced by the core of a PWR reactor of Bugey power plant has been used to search for evidence of neutrino oscillations through the inverse beta decay reaction [MATH]e + p → e+ + n. Measurements have been performed at two distances (13.5 and 18.5m). About 50 000 [MATH]e events have been collected at the first position and 25 000 [MATH]e events at the second one. Data analysis is almost completed

Role of superantigenic strains in the prognosis of community-acquired methicillin-susceptible Staphylococcus aureus bacteraemia

ABSTRACTMethicillin-susceptible Staphylococcus aureus (MSSA) strains can produce superantigenic toxins that may trigger a massive release of pro-inflammatory cytokines, which are involved in the onset of septic shock. This 1-year prospective pilot study assessed the role of the production of superantigenic toxins in the outcome of immunocompetent patients hospitalised for community-acquired MSSA bacteraemia. Thirty-seven patients were enrolled, of whom 14 died in hospital. Fourteen patients had septic shock, and the mortality rate in this subgroup was 56%. Twenty-seven (73%) isolates produced at least one superantigenic toxin, but this did not influence the rate of occurrence of septic shock or death

Alignment of the medial tibial plateau affects the rate of joint space narrowing in the osteoarthritic knee

SummaryObjectiveTo determine, in serial fixed-flexion (FF) radiographs of subjects with knee osteoarthritis (KOA), the importance of, and basis for, the effect of alignment of the medial tibial plateau (MTP), as determined by the inter-margin distance (IMD), on joint space narrowing (JSN).MethodsBaseline and 12-month X-rays of 590 knees with Kellgren and Lawrence grade (KLG) 2/3 OA from the public-release dataset of the Osteoarthritis Initiative (OAI) were assigned to subgroups based upon IMD at baseline (IMDBL) and the difference between IMDBL and IMD12mos. Relationships of JSN to IMDBL and to the difference between IMDBL and IMD12mos were evaluated.ResultsIn all 590 knees, mean JSN was 0.13±0.51mm (P<0.0001) and MTP alignment and replication of IMDBL in the 12-month film were, in general, poor. JSN was significantly (P=0.012) more rapid in Subgroup A (IMD≤1.70mm at both time points) than in Subgroup B (both IMDs>1.70mm): 0.15±0.43; 0.08±0.47. Within Subgroup B we identified a subset, Subgroup B1, in which, although alignment was poor at both time points, the large IMDBL was, by chance, highly reproduced by IMD12mos (difference between the two IMDs=0.01±0.27mm, NS). JSN in Subgroup B1 was 0.06±0.41mm and did not differ from that in other knees of Subgroup B (P=0.87). The standardized response mean (SRM) in all 590 knees and Subgroups A, B and B1 was 0.25, 0.34, 0.17 and 0.06, respectively. Independent of IMDBL, JSN correlated significantly with the difference between the IMDs in the two radiographs (r=0.17, P=0.0001).ConclusionSkewed MTP alignment in serial films and poor replication of IMDBL in the follow-up exam affect JSN measurement. The magnitude of change in joint space width (JSW) related to the poor quality of alignment that is common with the FF view jeopardizes accurate evaluation of JSN

The Thinking State?

Political Scienc

Derivation of fluid dynamics from kinetic theory with the 14--moment approximation

We review the traditional derivation of the fluid-dynamical equations from kinetic theory according to Israel and Stewart. We show that their procedure to close the fluid-dynamical equations of motion is not unique. Their approach contains two approximations, the first being the so-called 14-moment approximation to truncate the single-particle distribution function. The second consists in the choice of equations of motion for the dissipative currents. Israel and Stewart used the second moment of the Boltzmann equation, but this is not the only possible choice. In fact, there are infinitely many moments of the Boltzmann equation which can serve as equations of motion for the dissipative currents. All resulting equations of motion have the same form, but the transport coefficients are different in each case.Comment: 15 pages, 3 figures, typos fixed and discussions added; EPJA: Topical issue on "Relativistic Hydro- and Thermodynamics

Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study

Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p &lt; 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM &gt; 70 pg/ml upon admission than in those with bio-ADM ≤ 70 pg/ml. In patients with bio-ADM &gt; 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015