Phase transition in the collisionless regime for wave-particle interaction

Gibbs statistical mechanics is derived for the Hamiltonian system coupling self-consistently a wave to N particles. This identifies Landau damping with a regime where a second order phase transition occurs. For nonequilibrium initial data with warm particles, a critical initial wave intensity is found: above it, thermodynamics predicts a finite wave amplitude in the limit of infinite N; below it, the equilibrium amplitude vanishes. Simulations support these predictions providing new insight on the long-time nonlinear fate of the wave due to Landau damping in plasmas.Comment: 12 pages (RevTeX), 2 figures (PostScript

Responses to iron oxide and zinc oxide nanoparticles in echinoderm embryos and microalgae: uptake, growth, morphology, and transcriptomic analysis

We investigated the toxicity of Iron oxide and Zinc oxide engineered nanoparticles (ENPs) on Paracentrotus lividus sea urchin embryos and three species of microalgae. Morphological responses, internalization, and potential impacts of Fe2O3 and ZnO ENPs on physiology and metabolism were assessed. Both types of ENPs affected P. lividus larval development, but ZnO ENPs had a much stronger effect. While growth of the alga Micromonas commoda was severely impaired by both ENPs, Ostreococcus tauri or Nannochloris sp. were unaffected. Transmission electron microscopy showed the internalization of ENPs in sea urchin embryonic cells while only nanoparticle interaction with external membranes was evidenced in microalgae, suggesting that marine organisms react in diverse ways to ENPs. Transcriptome-wide analysis in P. lividus and M. commoda showed that many different physiological pathways were affected, some of which were common to both species, giving insights about the mechanisms underpinning toxic response

A Rat Model of Central Venous Catheter to Study Establishment of Long-Term Bacterial Biofilm and Related Acute and Chronic Infections

International audienceFormation of resilient biofilms on medical devices colonized by pathogenic microorganisms is a major cause of health-care associated infection. While in vitro biofilm analyses led to promising anti-biofilm approaches, little is known about their translation to in vivo situations and on host contribution to the in vivo dynamics of infections on medical devices. Here we have developed an in vivo model of long-term bacterial biofilm infections in a pediatric totally implantable venous access port (TIVAP) surgically placed in adult rats. Using non-invasive and quantitative bioluminescence, we studied TIVAP contamination by clinically relevant pathogens, Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus and Staphylococcus epidermidis , and we demonstrated that TIVAP bacterial populations display typical biofilm phenotypes. In our study, we showed that immunocompetent rats were able to control the colonization and clear the bloodstream infection except for up to 30% that suffered systemic infection and death whereas none of the immunosuppressed rats survived the infection. Besides, we mimicked some clinically relevant TIVAP associated complications such as port-pocket infection and hematogenous route of colonization. Finally, by assessing an optimized antibiotic lock therapy, we established that our in vivo model enables to assess innovative therapeutic strategies against bacterial biofilm infections

MA 07.06 Détection des mécanismes de résistance aux inhibiteurs d'ALK dans la pratique courante : une étude rétrospective

International audienceBackground: Treatment of ALK-rearranged Non-Small Cell Lung Cancer (NSCLC) relies on ALK tyrosine kinase inhibitors (TKI). However, efficacy of ALK TKI is limited by the emergence of drug resistance. ALK molecular alterations (amplification or mutation) account for about 40% of mechanisms of resistance to ALK TKI. Even though clinical and fundamental data suggest variability in drug efficacy according to the mechanism of resistance, these mutations are rarely investigated in routine practice. While targeted next-generation sequencing (t-NGS) is increasingly used for detecting molecular abnormalities, the impact of this tool in routine detection of ALK alterations is unknown. Method: We performed a retrospective multicentric study aiming at determining the frequency of ALK alterations using t-NGS in metastatic ALK-rearranged NSCLC patients progressing upon ALK TKI. Clinical, pathological, molecular characteristics, and patients outcome were collected. Result: We identified 22 patients with metastatic ALK-rearranged NSCLC who underwent a rebiopsy at progression on first ALK TKI, between January 2012 and May 2017. There were 12 females and 10 males, median age was 55, 18 patients (82%) were never smokers. Crizotinib was the first ALK TKI in 21 patients (95%). 15 patients (68%) received a second-generation ALK inhibitor and 3 patients (14%) received a third generation of ALK inhibitor. t-NGS on rebiopsy was performed in 16 patients. 6 ALK mutations (37.5%) were identified, including 3 G1202R, 1 C1156Y, 1 V1180L and 1 L1196M mutations . An ALK amplification (6%) was detected in a rebiopsy (6%) by FISH, with no concomitant ALK mutation. All ALK mutations were detected in solid biopsy, 2 ALK mutation was also detected in liquid biopsy. Median Overall Survival from first ALK TKI was 797 days (IC 95% 460-1135) and tended to be longer in patients with a known mechanism of resistance (1135 days Vs 543 days p¼0.2). Conclusion: Targeted NGS is feasible in routine practice for detection of mechanisms of resistance to ALK TKI in ALK-rearranged NSCLC patients and may help selecting the best treatment at progression upon ALK TKI

Standards, options et recommandations pour la prise en charge des neutropenies courtes

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Volatile Organic Compounds of Malignant Breast Cancer Wounds: Identification and Odors.

International audienceIntroduction. During the metabolic processes of malignant wounds, bacteria produce a large amount of volatile organic compounds (VOCs) that are responsible for malodors and may have a major impact on the patient's quality of life with a risk of isolation. Objective. A translational study was conducted on 32 malignant breast wounds by combining the identification of bacterial strains present on wounds, the identification of VOCs produced by these bacterial strains, and sensory evaluation to assess odor intensity and quality of odorous bacteria. Materials and Methods. Thirty-two patients with malignant breast cancer wounds > 10 cm(2) at various stages of the disease (curative or palliative) were included in the protocol. Volatile organic compounds were collected from primary dressings by headspace solid-phase microextraction and then analyzed by gas chromatography separation coupled with a mass spectrometer detector analysis. Microbiological samplings were taken and analyzed on agar plates. The odors of selected bacteria were assessed by a panel of staff members. Results. Proteus mirabilis and Fusobacterium necrophorum seem to produce the strongest and most typical malignant wound odor. The VOCs were analyzed and dimethyl disulfide, dimethyl trisulfide, phenol, indole, and 3-methylbutanal were found to be produced by bacteria generating the most typical wound odor. Conclusions. This study suggests the bacteria present in wounds may be responsible for odors. In addition, these findings could pave the way to engineer new types of dressings and to develop an evaluation method to assess their efficiency both quantitatively and qualitatively as well as improve quality of palliative care and comfort for women with malignant wounds

Optimization of Routine Testing for MET Exon 14 Splice Site Mutations in NSCLC Patients

International audienc

<i>In vivo</i> efficacy of ALT.

<p>ALT was instilled in the implanted colonized TIVAP (0 h) and associated with systemic vancomycin to treat <i>S. aureus</i> biofilm colonization. ALT was renewed every 24 h and its efficacy was monitored as photon emissions. Rats (n = 4, for each treatment) were sacrificed after 120 h of treatment and analyzed. (A) 5 mg/mL cefazolin ALT. (B) 1 mg/mL gentamicin ALT. (C) Combined cefazolin and gentamicin ALT (1∶1 v/v). (D–E) TIVAP were aseptically removed and photon emission due to remnant biofilm measured. (D) Cefazolin-treated TIVAP, (E) gentamicin-treated TIVAP and (F) TIVAP treated with cefazolin and gentamicin combination. In (A) to (F) representative experiments are shown. (G) TIVAP was extracted after treatment and cells were harvested and plated for CFU/mL. All the values are mean +/− standard deviation. Statistical analysis was done using one-way analysis of variance (ANOVA) using Graphpad Prism version 5.0c. p value<0.05 considered significant, *** (p<0.0001), ** (p<0.001) and * (p<0.05).</p