Publications by authors named "Lefevre P"

Gravity has long been purported to serve a unique role in sensorimotor coordination, but the specific mechanisms underlying gravity-based visuomotor realignment remain elusive. In this study, astronauts (9 males, 2 females) performed targeted hand movements with eyes open or closed, both on the ground and in weightlessness. Measurements revealed systematic drift in hand-path orientation seen only when eyes were closed and only in very specific conditions with respect to gravity.

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Pupil responses are commonly used to provide insight into visual perception, autonomic control, cognition, and various brain disorders. However, making inferences from pupil data can be complicated by nonlinearities in pupil dynamics and variability within and across individuals, which challenge the assumptions of linearity or group-level homogeneity required for common analysis methods. In this study, we evaluated luminance evoked pupil dynamics in young healthy adults (n = 10, M:F = 5:5, ages 19-25 years) by identifying nonlinearities, variability, and conserved relationships across individuals to improve the ability to make inferences from pupil data.

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Article Synopsis
  • Humans use smooth pursuit and saccades to track moving targets, with catch-up saccades correcting tracking errors.
  • The study examined how retinal acceleration error impacts saccade latency and amplitude during target pursuit.
  • Findings indicate that retinal acceleration error significantly predicts saccade parameters, suggesting it helps in estimating future target positions along with position and velocity errors.
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Background: Virtual simulation is increasingly used for aneurysm treatment. This study aimed to explore whether mechanical behavior biomarkers of the Woven EndoBridge (WEB) device as computed by Sim&Size simulation software were associated with aneurysmal occlusion status at follow-up.

Methods: Consecutive patients with aneurysms treated with WEB were retrospectively enrolled (January 2014 to December 2021).

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  • The study aimed to track the outcomes of patients with brain arteriovenous malformations (AVMs) who were managed conservatively, revealing key statistics on related morbidity and mortality over a 10-year period.
  • Out of 1010 patients initially recruited, 434 were analyzed, with a majority having unruptured low-grade AVMs, demonstrating a 5% occurrence of serious outcomes and a higher risk in those with a history of rupture or older age.
  • During the follow-up of approximately 3.2 years, 8% of patients experienced major intracranial hemorrhages, highlighting the ongoing risks associated with conservative management of AVMs.
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Background/objectives: Hydroxypropyl methylcellulose (HPMC) is one of the most commonly used hydrophilic polymers in formulations of matrix tablets for controlled release applications. However, HPMC attracts moisture and poses issues with drug stability in formulations containing moisture-sensitive drugs.

Methods: Herein, the moisture sorption behavior of excipients and drug stability using aspirin as the model drug in matrix tablets were evaluated, using HPMC and the newly developed mannitol-coated HPMC, under accelerated stability conditions (40 °C, 75% relative humidity) with open and closed dishes.

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  • Idiopathic intracranial hypertension (IIH) is linked to chronic headaches driven by high intracranial pressure (ICP) and potentially influenced by cerebral venous sinus pressure, which needs more research to understand their relationship.
  • A study investigated 52 patients suspected of having IIH, measuring both lumbar puncture opening pressure (LPOP) and cerebral venous sinus pressure, finding strong correlations between these measurements.
  • Results confirmed that the torcular pressure aligns closely with LPOP, indicating that these two methods are consistent for assessing ICP in IIH patients, which can help in clinical decision-making.
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We investigate the effect of finger moisture on the tactile perception of electroadhesion with 10 participants. Participants with moist fingers exhibited markedly higher threshold levels. Our electrical impedance measurements show a substantial reduction in impedance magnitude when sweat is present at the finger-touchscreen interface, indicating increased conductivity.

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Background: Antibody-mediated rejection (ABMR) poses a barrier to long-term graft survival and is one of the most challenging events after kidney transplantation. Removing donor specific antibodies (DSA) through therapeutic plasma exchange (PLEX) is a cornerstone of antibody depletion but has inconsistent effects. Imlifidase is a treatment currently utilized for desensitization with near-complete inactivation of DSA both in the intra- and extravascular space.

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One of the most common forms of controlled release technology for oral drug delivery comprises an active ingredient dispersed in a hydrophilic matrix forming polymer such as hydroxypropyl methylcellulose (HPMC), which is tableted via direct compression. However, HPMC may pose problems in direct compression due to its poor flowability. Hence, mannitol syrup was spray-coated over fluidized HPMC particles to produce co-processed HPMC-mannitol at ratios of 20:80, 50:50, and 70:30.

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Introduction: Too few patients benefit from endovascular therapy (EVT) in large vessel occlusion acute stroke (LVOS), and various acute stroke care paradigms are currently investigated to reduce these inequalities in health access. We aimed to investigate whether newly set-up thrombectomy-capable stroke centers (TSC) offered a safe, effective and cost-effective procedure.

Patients And Methods: This French retrospective study compared the outcomes of LVOS patients with an indication for EVT and treated at the Perpignan hospital before on-site thrombectomy was available (Primary stroke center), and after formation of local radiology team for neurointervention (TSC).

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Background: Performing endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) allows a port of entry for intracranial biological sampling.

Objective: To test the hypothesis that specific immune players are molecular contributors to disease, outcome biomarkers, and potential targets for modifying AIS .

Methods: We examined 75 subjects presenting with large vessel occlusion of the anterior circulation and undergoing EVT.

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Aims: Accurate determination of histological activity in ulcerative colitis (UC) is essential given its diagnostic and prognostic importance. Data on the relationship between histology and immune cell markers are limited. We aimed to evaluate the association between histological disease activity and immune cell marker concentration in colonic biopsies from patients with UC.

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Age assessment of migrants is crucial, particularly for unaccompanied foreign minors, a population facing legal, social, and humanitarian challenges. Despite existing guidelines, there is no unified protocol in Europe for age assessment.The Forensic Anthropology Society of Europe (FASE) conducted a comprehensive questionnaire to understand age estimation practices in Europe.

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Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) plaques and hyperphosphorylated tau in the brain. Aβ plaques precede cognitive impairments and can be detected through amyloid-positron emission tomography (PET) or in cerebrospinal fluid (CSF). Assessing the plasma Aβ42/Aβ40 ratio seems promising for non-invasive and cost-effective detection of brain Aβ accumulation.

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During object manipulation, humans adjust the grip force to friction, such that slippery objects are squeezed more firmly than sticky ones. This essential mechanism to keep a stable grasp relies on feedback from tactile afferents innervating the fingertips, that are sensitive to local skin strains. To test if this feedback originates from the skin-object interface, we asked participants to perform a grip-lift task with an instrumented object able to monitor skin strains at the contact through transparent plates of different frictions.

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Article Synopsis
  • * Past surgeries didn't really help these patients, but some doctors are looking into a new way called endovascular treatment to fix the blood flow to the brain.
  • * While some studies show that this new treatment is successful and safe, more research is needed to make sure it’s effective and can be used regularly.
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Humans use tactile feedback to perform skillful manipulation. When tactile sensory feedback is unavailable, for instance, if the fingers are anesthetized, dexterity is severely impaired. Imaging the deformation of the finger pad skin when in contact with a transparent plate provides information about the tactile feedback received by the central nervous system.

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Background: The safety and efficacy of low-profile braided stent as stent monotherapy require further investigation.

Objective: To analyze patient outcomes after treatment with braided stents used as "light" flow diverters.

Material/methods: Retrospective study to evaluate the occlusion rate of aneurysms treated with braided stent and remodeling of covered side branches and perforators.

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Humans consider the parameters linked to movement goal during reaching to adjust their control strategy online. Indeed, rapid changes in target structure or disturbances interfering with their initial plan elicit rapid changes in behavior. Here, we hypothesize that these changes could result from the continuous use of a decision variable combining motor and cognitive components.

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Path integration is a spatial navigation ability that requires the integration of information derived from self-motion cues and stable landmarks, when available, to return to a previous location. Path integration declines with age and Alzheimer's disease (AD). Here, we sought to separate the effects of age and AD risk on path integration, with and without a landmark.

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Human dexterity requires very fine and efficient control of fingertip forces, which relies on the integration of cutaneous and proprioceptive feedback. Here, we examined the influence of gravity on isometric force control. We trained participants to reproduce isometric vertical forces on a dynamometer held between the thumb and the index finger in normal gravity and tested them during parabolic flight creating phases of microgravity and hypergravity, thereby strongly influencing the motor commands and the proprioceptive feedback.

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Purpose: This study aimed to evaluate the performance and ease of use of the Revogene GBS DS PCR assay for the intrapartum detection of Group B Streptococcus (GBS) colonization, as compared with intrapartum culture and antenatal culture-based screening.

Methods: Between April and August 2019, 398 women who gave birth in one of the three maternities participating in this study agreed to the collection of a vaginal swab when they arrived in the labor ward. The samples were immediately sent to the adjacent laboratory where they were discharged into the buffer provided with the Revogene GBS DS assay.

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Background: Clinical trials of novel therapies for the treatment of ulcerative colitis (UC) may benefit from immune cell profiling, however implementation of this methodology is limited in the multicenter trial setting by necessity of timely (within 6 to 8 h) isolation and processing of peripheral blood mononuclear cells (PBMC) from whole blood samples. Becton Dickinson Vacutainer CPT™ Cell Preparation Tubes (CPT™) limit required processing prior to shipping to a central lab to an initial centrifugation step within 24 h of sample collection. As shipping may delay final processing beyond 24 h, we analyzed cell viability and T cell composition in whole blood stored in CPT™ to determine if their use may accommodate processing delays typical for multicenter clinical trials.

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