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result(s) for
"Fournier, Justin"
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Apelin-13 in septic shock: effective in supporting hemodynamics in sheep but compromised by enzymatic breakdown in patients
2021
Sepsis is a prevalent life-threatening condition related to a systemic infection, and with unresolved issues including refractory septic shock and organ failures. Endogenously released catecholamines are often inefficient to maintain blood pressure, and low reactivity to exogenous catecholamines with risk of sympathetic overstimulation is well documented in septic shock. In this context, apelinergics are efficient and safe inotrope and vasoregulator in rodents. However, their utility in a larger animal model as well as the limitations with regards to the enzymatic breakdown during sepsis, need to be investigated. The therapeutic potential and degradation of apelinergics in sepsis were tested experimentally and in a cohort of patients. (1) 36 sheep with or without fecal peritonitis-induced septic shock (a large animal experimental design aimed to mimic the human septic shock paradigm) were evaluated for hemodynamic and renal responsiveness to incremental doses of two dominant apelinergics: apelin-13 (APLN-13) or Elabela (ELA), and (2) 52 subjects (33 patients with sepsis/septic shock and 19 healthy volunteers) were investigated for early levels of endogenous apelinergics in the blood, the related enzymatic degradation profile, and data regarding sepsis outcome. APLN-13 was the only one apelinergic which efficiently improved hemodynamics in both healthy and septic sheep. Endogenous apelinergic levels early rose, and specific enzymatic breakdown activities potentially threatened endogenous apelin system reactivity and negatively impacted the outcome in human sepsis. Short-term exogenous APLN-13 infusion is helpful in stabilizing cardiorenal functions in ovine septic shock; however, this ability might be impaired by specific enzymatic systems triggered during the early time course of human sepsis. Strategies to improve resistance of APLN-13 to degradation and/or to overcome sepsis-induced enzymatic breakdown environment should guide future works.
Journal Article
Development of a Lesson Sequence on the Nature of Light Using Argumentation and Modeling in the Classroom
2021
In an effort to provide more weight to the particle nature of light, a lesson sequence was developed that reflected the Next Generation Science Standard (NGSS) Performance Expectation (PE) HS-PS4-3, which has students evaluating the claim, evidence, and reasoning behind the idea that electromagnetic radiation can be described by either the wave model or the particle model and that one model is often more useful than another in investigating a particular phenomenon. The lesson sequence was developed with a key focus on modeling and student argumentation and is structured in a historical order. Four lessons were developed on the topics of Blackbody Radiation and the Ultraviolet Catastrophe, the photelectric effect, the Compton effect, and the Bohr model of the atom. Two “argumentation sessions” were added; one in the middle of the four lessons and at the other at the end of the lesson sequence where students engaged in scientific argumentation to answer the question, “Is light better modeled as a particle, a wave, both, or neither?” The lesson sequence was reviewed by experts in argumentation, content, and physics teaching and feedback was provided through a set of surveys targeted toward each type of expert. Specifically, questions were asked about where argumentation and teaching experts felt components of argumentation and modeling were evident in the lesson sequence as well as whether the same components were accurately reflecting the intent of the NGSS. Analysis of the feedback found that the experts identified evidence of modeling and argumentation in the lesson sequence in sections that was deliberately placed when the sequence was developed. Experts also felt that the use of modeling and argumentation accurately reflected the intent of the NGSS. Experts also agreed that the historical structure of the lesson sequence, its reflection on the Nature of Science (NOS) and how science develops its ideas were of the strongest aspects of the lesson sequence. Expert suggestions for improvement fell into four categories: (1) changing the roll of student argumentation at the end of the unit, (2) improving the organization within the lesson sequence, (3) provide more support for students (in particular being explicit with the use of models and skill students were working on), and (4) providing clarity in content within the lesson. Expert suggested changes were made to the lesson sequence and shared with colleagues.
Dissertation
State of the Field: Extreme Precision Radial Velocities
2016
The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm s(-1) measurement precision. The presentations and discussion of key issues for instrumentation and data analysis and the workshop recommendations for achieving this bold precision are summarized here. Beginning with the High Accuracy Radial Velocity Planet Searcher spectrograph, technological advances for precision radial velocity (RV) measurements have focused on building extremely stable instruments. To reach still higher precision, future spectrometers will need to improve upon the state of the art, producing even higher fidelity spectra. This should be possible with improved environmental control, greater stability in the illumination of the spectrometer optics, better detectors, more precise wavelength calibration, and broader bandwidth spectra. Key data analysis challenges for the precision RV community include distinguishing center of mass (COM) Keplerian motion from photospheric velocities (time correlated noise) and the proper treatment of telluric contamination. Success here is coupled to the instrument design, but also requires the implementation of robust statistical and modeling techniques. COM velocities produce Doppler shifts that affect every line identically, while photospheric velocities produce line profile asymmetries with wavelength and temporal dependencies that are different from Keplerian signals. Exoplanets are an important subfield of astronomy and there has been an impressive rate of discovery over the past two decades. However, higher precision RV measurements are required to serve as a discovery technique for potentially habitable worlds, to confirm and characterize detections from transit missions, and to provide mass measurements for other space-based missions. The future of exoplanet science has very different trajectories depending on the precision that can ultimately be achieved with Doppler measurements.
Journal Article
Control of Phytonemus pallidus (Acari: Tarsonemidae) from strawberry transplants using controlled atmosphere temperature treatment
by
Lefebvre, Nicholas
,
Renkema, Justin
,
Fournier, Valérie
in
Analysis
,
Atmospheric temperature
,
COMMODITY TREATMENT AND QUARANTINE ENTOMOLOGY
2023
Since it inhabits young leaves and buds of strawberry (Fragaria × ananassa Duchesne) crowns, cyclamen mite (Phytonemus pallidus Banks) is a difficult pest to control with biological or chemical means once it is present in a field. Controlled atmosphere temperature treatment (CATT) is a successful technique that has been commercially used in the Netherlands for nearly 2 decades to disinfect strawberry nursery stock, including elimination of cyclamen mite. During CATT, plants are treated at 35 °C, 50% CO2, and 10% O2 under high relative humidity for 48 h. The objective of this study was to test CATT against P. pallidus in North America at a scale that can be easily used on-farms by strawberry growers. Two greenhouse experiments were conducted where infested trayplants were treated with CATT or the acaricide abamectin, and P. pallidus number were compared to control plants. Plants were destructively sampled after 4 weeks, and CATT reduced mobile forms of P. pallidus by 99.9% in both experiments. Abamectin used in the first experiment had an efficacy of 95.5%. Our findings suggest that CATT is effective at nearly eliminating P. pallidus from strawberry planting material, and its application could reduce risks of field infestations and the need for multiple acaricide applications. While our results are encouraging, additional research is needed to assess the effects of CATT on strawberry plant survival, growth, and fruit production.
Journal Article
Bacterial cyclic diguanylate signaling networks sense temperature
2021
Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, we identify a thermosensory diguanylate cyclase (TdcA) that modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen
Pseudomonas aeruginosa
. TdcA synthesizes c-di-GMP with catalytic rates that increase more than a hundred-fold over a ten-degree Celsius change. Analyses using protein chimeras indicate that heat-sensing is mediated by a thermosensitive Per-Arnt-SIM (PAS) domain. TdcA homologs are widespread in sequence databases, and a distantly related, heterologously expressed homolog from the Betaproteobacteria order
Gallionellales
also displayed thermosensitive diguanylate cyclase activity. We propose, therefore, that thermotransduction is a conserved function of c-di-GMP signaling networks, and that thermosensitive catalysis of a second messenger constitutes a mechanism for thermal sensing in bacteria.
Many bacteria use the second messenger cyclic diguanylate (c-di-GMP) to control motility, biofilm production and virulence. Here, the authors identify a thermosensitive enzyme that synthesizes c-di-GMP and modulates temperature-dependent motility, biofilm development and virulence in the opportunistic pathogen
Pseudomonas aeruginosa
.
Journal Article
Exploring Communication Dynamics Between Patients and Healthcare Providers in Oncology: A Systematic Review
2025
Objective Patient–physician communication in oncology has been studied extensively. Most studies have focused on healthcare professionals' (HCPs) communication, showing the importance of a patient‐centred approach. While some studies have explored the behaviours of patients and their relatives, the majority have centred on HCPs' behaviours, with much less attention to patients' communication patterns during consultations. The main objective of this systematic review was to examine how patients communicate and behave during oncology consultations and to identify the factors influencing these behaviours. Methods Five databases were searched to find studies analyzing the communication patterns of patients and their relatives during oncology consultations that were audio‐ and/or video‐recorded. Results Based on the 34,779 references identified, we included 47 studies in our review. Three main themes emerged from the analysis: (1) patients' communication patterns and the topics discussed during oncology consultations; (2) factors influencing patient communication; and (3) patients' perception of and satisfaction with the consultation. Conclusions Patients exhibited active behaviours during consultations. However, many factors can influence interactions. We recommend taking a comprehensive approach that involves considering communication factors and supporting the development of patient‐centred strategies tailored to individual patient needs. HCPs should not only practice patient‐centred care; they should also implement specific actions to address patients' psychosocial needs. Future research should also utilize complex models to better understand the dynamics of patient–provider communication.
Journal Article
Ability of Muscidifurax raptorellus and Other Parasitoids and Predators to Control Drosophila suzukii Populations in Raspberries in the Laboratory
by
Bonneau, Phanie
,
Renkema, Justin
,
Fournier, Valérie
in
adults
,
Biological control
,
Chrysoperla carnea
2019
Drosophila suzukii is an invasive pest and economic threat to berry crops in Europe and the Americas. Current methods of control of this pest rely primarily on frequent applications of insecticides; therefore, there is a need for alternative control methods to reduce insecticide reliance. In this study, we evaluated the biological control potential of three parasitoid wasps: Diglyphus isaea, Muscidifurax raptorellus and Pachycrepoideus vindemmiae, and four predators: Chrysoperla carnea, Dicyphus hesperus, Orius insidiosus and Podisus maculiventris. Experiments were conducted for 15 days under controlled conditions in experimental arenas with D. suzukii females and raspberries, allowing for all life stages of D. suzukii to be available to natural enemies. Results showed the first evidence of M. raptorellus’s ability to parasitize D. suzukii, resulting in a 40% reduction. Orius insidiosus, P. vindemmiae and C. carnea were also efficient, reducing D. suzukii numbers by 49%, 43% and 32%, respectively. Predator preferences for each D. suzukii life stage were assessed. The clutch size, sex ratio and adult size variability of D. suzukii pupal parasitoids were also evaluated. This study expands the list of species that can effectively parasitize D. suzukii and provides new insights into the biological responses of M. raptorellus to D. suzukii pupae.
Journal Article
Is minor surgery safe during the COVID-19 pandemic? A multi-disciplinary study
by
Mhatli, Mehdi
,
Wazne, Yann
,
Michel, Justin
in
Anesthesia
,
Bacteriology
,
Biology and Life Sciences
2021
To assess the risk of postoperative SARS-CoV-2 infection during the COVID-19 pandemic.
The CONCEPTION study was a cohort, multidisciplinary study conducted at Conception University Hospital, in France, from March 17th to May 11th, 2020. Our study included all adult patients who underwent minor surgery in one of the seven surgical departments of our hospital: urology, digestive, plastic, gynecological, otolaryngology, gynecology or maxillofacial surgery. Preoperative self-isolation, clinical assessment using a standardized questionnaire, physical examination, nasopharyngeal RT-PCR and chest CT scan performed the day before surgery were part of our active prevention strategy. The main outcome was the occurrence of a SARS-CoV-2 infection within 21 days following surgery. The COVID-19 status of patients after discharge was updated during the postoperative consultation and to ensure the accuracy of data, all patients were contacted again by telephone.
A total of 551 patients from six different specialized surgical Departments in our tertiary care center were enrolled in our study. More than 99% (546/551) of included patients underwent a complete preoperative Covid-19 screening including RT-PCR testing and chest CT scan upon admission to the Hospital. All RT-PCR tests were negative and in 12 cases (2.2%), preoperative chest CT scans detected pulmonary lesions consistent with the diagnosis criteria for COVID-19. No scheduled surgery was postponed. One patient (0.2%) developed a SARS-CoV-2 infection 20 days after a renal transplantation. No readmission or COVID-19 -related death within 30 days from surgery was recorded.
Minor surgery remained safe in the COVID-19 Era, as long as all appropriate protective measures were implemented. These data could be useful to public Health Authorities in order to improve surgical patient flow during a pandemic.
Journal Article
Effect of sodium phenylbutyrate/taurursodiol on tracheostomy/ventilation-free survival and hospitalisation in amyotrophic lateral sclerosis: long-term results from the CENTAUR trial
by
Scelsa, Stephen N
,
Shefner, Jeremy M
,
Chase, Marianne
in
Amyotrophic lateral sclerosis
,
Drug dosages
,
Hospitalization
2022
BackgroundCoformulated sodium phenylbutyrate/taurursodiol (PB/TURSO) was shown to prolong survival and slow functional decline in amyotrophic lateral sclerosis (ALS).ObjectiveDetermine whether PB/TURSO prolonged tracheostomy/ventilation-free survival and/or reduced first hospitalisation in participants with ALS in the CENTAUR trial.MethodsAdults with El Escorial Definite ALS ≤18 months from symptom onset were randomised to PB/ TURSO or placebo for 6 months. Those completing randomised treatment could enrol in an open-label extension (OLE) phase and receive PB/TURSO for ≤30 months. Times to the following individual or combined key events were compared in the originally randomised treatment groups over a period spanning trial start through July 2020 (longest postrandomisation follow-up, 35 months): death, tracheostomy, permanent assisted ventilation (PAV) and first hospitalisation.ResultsRisk of any key event was 47% lower in those originally randomised to PB/TURSO (n=87) versus placebo (n=48, 71% of whom received delayed-start PB/TURSO in the OLE phase) (HR=0.53; 95% CI 0.35 to 0.81; p=0.003). Risks of death or tracheostomy/PAV (HR=0.51; 95% CI 0.32 to 0.84; p=0.007) and first hospitalisation (HR=0.56; 95% CI 0.34 to 0.95; p=0.03) were also decreased in those originally randomised to PB/TURSO.ConclusionsEarly PB/TURSO prolonged tracheostomy/PAV-free survival and delayed first hospitalisation in ALS.Trial registration number NCT03127514; NCT03488524.
Journal Article
Genome-Wide CRISPR Screen Identifies KEAP1 Perturbation as a Vulnerability of ARID1A-Deficient Cells
2024
ARID1A is the core DNA-binding subunit of the BAF chromatin remodeling complex and is mutated in about 8% of all cancers. The frequency of ARID1A loss varies between cancer subtypes, with clear cell ovarian carcinoma (CCOC) presenting the highest incidence at > 50% of cases. Despite a growing understanding of the consequences of ARID1A loss in cancer, there remains limited targeted therapeutic options for ARID1A-deficient cancers. Using a genome-wide CRISPR screening approach, we identify KEAP1 as a genetic dependency of ARID1A in CCOC. Depletion or chemical perturbation of KEAP1 results in selective growth inhibition of ARID1A-KO cell lines and edited primary endometrial epithelial cells. While we confirm that KEAP1-NRF2 signalling is dysregulated in ARID1A-KO cells, we suggest that this synthetic lethality is not due to aberrant NRF2 signalling. Rather, we find that KEAP1 perturbation exacerbates genome instability phenotypes associated with ARID1A deficiency. Together, our findings identify a potentially novel synthetic lethal interaction of ARID1A-deficient cells.
Journal Article