Polymer reptation and nucleosome repositioning

We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.Comment: 9 pages, including 2 figures, to be published in Phys. Rev. Let

Multicenter evaluation of a lateral-flow device test for diagnosing invasive pulmonary aspergillosis in ICU patients

Introduction: The incidence of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients is increasing, and early diagnosis of the disease and treatment with antifungal drugs is critical for patient survival. Serum biomarker tests for IPA typically give false-negative results in non-neutropenic patients, and galactomannan (GM) detection, the preferred diagnostic test for IPA using bronchoalveolar lavage (BAL), is often not readily available. Novel approaches to IPA detection in ICU patients are needed. In this multicenter study, we evaluated the performance of an Aspergillus lateral-flow device (LFD) test for BAL IPA detection in critically ill patients. Methods: A total of 149 BAL samples from 133 ICU patients were included in this semiprospective study. Participating centers were the medical university hospitals of Graz, Vienna and Innsbruck in Austria and the University Hospital of Mannheim, Germany. Fungal infections were classified according to modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. Results: Two patients (four BALs) had proven IPA, fourteen patients (sixteen BALs) had probable IPA, twenty patients (twenty-one BALs) had possible IPA and ninety-seven patients (one hundred eight BALs) did not fulfill IPA criteria. Sensitivity, specificity, negative predictive value, positive predictive value and diagnostic odds ratios for diagnosing proven and probable IPA using LFD tests of BAL were 80%, 81%, 96%, 44% and 17.6, respectively. Fungal BAL culture exhibited a sensitivity of 50% and a specificity of 85%. Conclusion: LFD tests of BAL showed promising results for IPA diagnosis in ICU patients. Furthermore, the LFD test can be performed easily and provides rapid results. Therefore, it may be a reliable alternative for IPA diagnosis in ICU patients if GM results are not rapidly available. Trial registration: ClinicalTrials.gov NCT02058316. Registered 20 January 2014

Drivers and impact of antifungal therapy in critically ill patients with Aspergillus-positive respiratory tract cultures

Invasive pulmonary aspergillosis (IPA) is an increasingly recognised problem in critically ill patients. Little is known about how intensivists react to an Aspergillus-positive respiratory sample or the efficacy of antifungal therapy (AFT). This study aimed to identify drivers of AFT prescription and diagnostic workup in patients with Aspergillus isolation in respiratory specimens as well as the impact of AFT in these patients. ICU patients with an Aspergillus-positive respiratory sample from the database of a previous observational, multicentre study were analysed. Cases were classified as proven/putative IPA or Aspergillus colonisation. Demographic, microbiological, diagnostic and therapeutic data were collected. Outcome was recorded 12 weeks after Aspergillus isolation. Patients with putative/proven IPA were more likely to receive AFT than colonised patients (78.7% vs. 25.5%; P 7) (68.4% vs. 36.9%) (both P < 0.001). Once adjusted for disease severity, initiation of AFT did not alter the odds of survival (HR = 1.40, 95% CI 0.89–2.21). Likewise, treatment within 48 h following diagnosis did not change the clinical outcome (75.7% vs. 61.4%; P = 0.63). Treatment decisions appear to be based on diagnostic criteria and underlying disease severity at the time of Aspergillus isolation. IPA in this population has a dire prognosis and AFT is not associated with reduced mortality. This may be explained by delayed diagnosis and an often inevitable death due to advanced multiorgan failure

Noether theorem for mu-symmetries

We give a version of Noether theorem adapted to the framework of mu-symmetries; this extends to such case recent work by Muriel, Romero and Olver in the framework of lambda-symmetries, and connects mu-symmetries of a Lagrangian to a suitably modified conservation law. In some cases this "mu-conservation law'' actually reduces to a standard one; we also note a relation between mu-symmetries and conditional invariants. We also consider the case where the variational principle is itself formulated as requiring vanishing variation under mu-prolonged variation fields, leading to modified Euler-Lagrange equations. In this setting mu-symmetries of the Lagrangian correspond to standard conservation laws as in the standard Noether theorem. We finally propose some applications and examples.Comment: 28 pages, to appear in J. Phys.

Spontaneous life-threatening hemobilia during acute liver failure successfully treated with transarterial embolization

A 28-year-old patient admitted with jaundice, vomiting and deteriorating coagulopathy was diagnosed with acute liver failure. After listing for urgent transplantation, he developed Boerhaave’s syndrome and massive hemobilia, two life-threatening complications. Massive hemobilia secondary to a fistula between the right hepatic artery and the right bile duct occurred several days after transjugular biopsy and was controlled with fluid resuscitation, transfusion and arterial embolization. Two days later he was transplanted successfully, and is currently doing well after more than 72 months. Aggressive treatment of potentially reversible complications during acute liver failure whilst awaiting transplantation is mandatory to allow survival of these patients