Studies have shown that adaptation to a virtual reality driving simulator takes time and that individuals differ widely in the time they need to adapt. The present study examined the relationship between attentional capacity and driving-simulator adaptation, with the hypothesis that individuals with better attentional capacity would exhibit more efficient adaptation to novel virtual driving circumstances. To this end, participants were asked to steer in a driving simulator through a series of 100 bends while keeping within a central demarcated zone.
View Article and Find Full Text PDFRecent research indicates that installing shoulders on rural roads for safety purposes causes drivers to steer further inside on right bends and thus exceed lane boundaries. The present simulator study examined whether continuous rather than broken edge-line delineation would help drivers to keep their vehicles within the lane. The results indicated that continuous delineation significantly impacts the drivers' gaze and steering trajectories.
View Article and Find Full Text PDFIntroduction: sporozoites (SPZ) inoculated by mosquitoes into the skin of the mammalian host migrate to the liver before infecting hepatocytes. Previous work demonstrated that early production of IL-6 in the liver is detrimental for the parasite growth, contributing to the acquisition of a long-lasting immune protection after immunization with live attenuated parasites.
Methods: Considering that IL-6 as a critical pro-inflammatory signal, we explored a novel approach whereby the parasite itself encodes for the murine IL-6 gene.
We examined the role of phonemic awareness [PA], rapid naming [RAN], and verbal short-term memory [VSTM], phonological verbal fluency (PVF) along with literacy related skills (letter naming and orthographic knowledge) in reading, spelling, and numeracy performances. The study was carried out on a sample that consists of 245 native Arabic children of grade 1 and 2. The results showed a significant effect of Group on PA, RAN, VSTM, PVF, and letter naming and orthographic knowledge.
View Article and Find Full Text PDFThe installation of shoulders on rural roads to create more forgiving roads encourages drivers to cut corners on right-hand bends, but the underlying mechanisms are poorly understood. Since eye movements and steering control are closely coupled, this study investigated how the presence of a shoulder influences drivers' gaze strategies. To this end, eighteen drivers negotiated right-hand bends with and without a shoulder on a simulated rural road.
View Article and Find Full Text PDFEpigenetic post-translational modifications are essential for human malaria parasite survival and progression through its life cycle. Here, we present new functionalized suberoylanilide hydroxamic acid (SAHA) derivatives that chemically combine the pan-histone deacetylase inhibitor SAHA with the DNA methyltransferase inhibitor procainamide. A three- or four-step chemical synthesis was designed starting from cheap raw materials.
View Article and Find Full Text PDFJ Venom Anim Toxins Incl Trop Dis
May 2021
Infection with vector-borne pathogens starts with the inoculation of these pathogens during blood feeding. In endemic regions, the population is regularly bitten by naive vectors, implicating a permanent stimulation of the immune system by the vector saliva itself (pre-immune context). Comparatively, the number of bites received by exposed individuals from non-infected vectors is much higher than the bites from infected ones.
View Article and Find Full Text PDFDeciphering the mechanisms by which parasites develop inside hepatocytes is an important step toward the understanding of malaria pathogenesis. We propose that the nature and the magnitude of the inflammatory response in the liver are key for the establishment of the infection. Here, we used mice deficient in the multidrug resistance-2 gene (Mdr2)-encoded phospholipid flippase leading to the development of liver inflammation.
View Article and Find Full Text PDFDue to the lack of efficiency to control malaria elicited by sub-unit vaccine preparations, vaccination with live-attenuated Plasmodium parasite as reported 70 years ago with irradiated sporozoites regained recently a significant interest. The complex life cycle of the parasite and the different stages of development between mammal host and anopheles do not help to propose an easy vaccine strategy. In order to achieve a complete long-lasting protection against Plasmodium infection and disease, we considered a genetically attenuated blood stage parasite in the hmgb2 gene coding for the high-mobility-group-box 2 (HMGB2).
View Article and Find Full Text PDFMalaria is the deadliest parasitic disease affecting over 200 million people worldwide. The increasing number of treatment failures due to multi-drug-resistant parasites in South-East Asia hinders the efforts for elimination. It is thus urgent to develop new antimalarials to contain these resistant parasites.
View Article and Find Full Text PDFThis study investigated split-step timing when returning serves and whether this timing is related to neuromechanical capabilities in world-class tennis players. In Experiment 1, the split-step timing of four groups of world-class players (male and female ATP/WTA seniors, and ITF juniors) was measured on court when returning serves of the same level players. The four groups initiated the split-step at a similar time, starting around the time ball-racket contact in the serve stroke and landed when early ball-flight information was available.
View Article and Find Full Text PDFProtozoan pathogens secrete nanosized particles called extracellular vesicles (EVs) to facilitate their survival and chronic infection. Here, we show the inhibition by Plasmodium berghei NK65 blood stage-derived EVs of the proliferative response of CD4 T cells in response to antigen presentation. Importantly, these results were confirmed in vivo by the capacity of EVs to diminish the ovalbumin-specific delayed type hypersensitivity response.
View Article and Find Full Text PDFBackground: Basophils are commonly associated with allergic responses because of their ability to produce large amounts of pro-Th2 cytokines and histamine. However, the mechanisms through which bone marrow-resident basophils (BMRB) become fully competent cytokine and histamine producers in response to IgE crosslinking are poorly understood. Here, we sought to determine the role of IL-3 in promoting pro-Th2 basophils.
View Article and Find Full Text PDFObjective: The aim of this study was to investigate steering control in a low-cost driving simulator with and without a virtual vehicle cab.
Background: In low-cost simulators, the lack of a vehicle cab denies driver access to vehicle width, which could affect steering control, insofar as locomotor adjustments are known to be based on action-scaled visual judgments of the environment.
Method: Two experiments were conducted in which steering control with and without a virtual vehicle cab was investigated in a within-subject design, using cornering and straight-lane-keeping tasks.
While most subunit malaria vaccines provide only limited efficacy, pre-erythrocytic and erythrocytic genetically attenuated parasites (GAP) have been shown to confer complete sterilizing immunity. We recently generated a Plasmodium berghei (PbNK65) parasite that lacks a secreted factor, the histamine releasing factor (HRF) (PbNK65 hrfΔ), and induces in infected mice a self-resolving blood stage infection accompanied by a long lasting immunity. Here, we explore the immunological mechanisms underlying the anti-parasite protective properties of the mutant PbNK65 hrfΔ and demonstrate that in addition to an up-regulation of IL-6 production, CD4 but not CD8 T effector lymphocytes are indispensable for the clearance of malaria infection.
View Article and Find Full Text PDFPrevious research has shown that lane-width reduction makes drivers operate vehicles closer to the center of the road whereas hard-shoulder widening induces a position farther away from the road's center. The goal of the present driving-simulator study was twofold. First, it was aimed at further investigating the respective effects of lane and shoulder width on in-lane positioning strategies, by examining vehicle distance from the center of the lane.
View Article and Find Full Text PDFAccording to the WHO, and despite reduction in mortality rates, there were an estimated 438 000 malaria deaths in 2015. Therefore new antimalarials capable of limiting organ damage are still required. We show that systemic and lung adenovirus (Ad)-mediated over-expression of trappin-2 (T-2) an antibacterial molecule with anti-inflammatory activity, increased mice survival following infection with the cerebral malaria-inducing Plasmodium berghei ANKA (PbANKA) strain.
View Article and Find Full Text PDFAlthough most vaccines against blood stage malaria in development today use subunit preparations, live attenuated parasites confer significantly broader and more lasting protection. In recent years, Plasmodium genetically attenuated parasites (GAPs) have been generated in rodent models that cause self-resolving blood stage infections and induce strong protection. All such GAPs generated so far bear mutations in housekeeping genes important for parasite development in red blood cells.
View Article and Find Full Text PDFEpigenetic control via reversible histone methylation regulates transcriptional activation throughout the malaria parasite genome, controls the repression of multi-copy virulence gene families and determines sexual stage commitment. Plasmodium falciparum encodes ten predicted SET domain-containing protein methyltransferases, six of which have been shown to be refractory to knock-out in blood stage parasites. We have expressed and purified the first recombinant malaria methyltransferase in sufficient quantities to perform a full enzymatic characterization and reveal the ill-defined PfSET7 is an AdoMet-dependent histone H3 lysine methyltransferase with highest activity towards lysines 4 and 9.
View Article and Find Full Text PDFBackground: The World Allergy Organization estimates that 40 % of the world's population is affected by allergic diseases. The International Study of Asthma and Allergies in Childhood has completed Phase III and it has now become clear that these diseases have increased in developing countries, especially Africa, where prevalence rates were formerly low. Despite an increase in studies in Africa, few sub-Saharan West African countries are represented; the focus has remained on urban populations and little attention has been paid to rural sub-Saharan Africa.
View Article and Find Full Text PDFEukaryotic high-mobility-group-box (HMGB) proteins are nuclear factors involved in chromatin remodeling and transcription regulation. When released into the extracellular milieu, HMGB1 acts as a proinflammatory cytokine that plays a central role in the pathogenesis of several immune-mediated inflammatory diseases. We found that the Plasmodium genome encodes two genuine HMGB factors, Plasmodium HMGB1 and HMGB2, that encompass, like their human counterparts, a proinflammatory domain.
View Article and Find Full Text PDFPlasmodium spp., which causes malaria, produces a histamine-releasing factor (HRF), an orthologue of mammalian HRF. Histamine-releasing factor produced by erythrocytic stages of the parasite is thought to play a role in the pathogenesis of severe malaria.
View Article and Find Full Text PDFObjective: Anaphylaxis is a life-threatening outcome of immediate-type hypersensitivity to allergen, consecutive to mast cell degranulation by allergen-specific IgE. Regulatory T cells (Treg) can control allergic sensitization and mast cell degranulation, yet their clinical benefit on anaphylactic symptoms is poorly documented. Here we investigated whether Treg action during the effector arm of the allergic response alleviates anaphylaxis.
View Article and Find Full Text PDFObjectives: To assess the impact of atopy and allergy on the risk of clinical malaria.
Design: A clinical and immunological allergy cross-sectional survey in a birth cohort of 175 children from 1 month to 14 years of age followed for up to 15 years in a longitudinal open cohort study of malaria in Senegal. Malaria incidence data were available for 143 of these children (aged 4 months to 14 years of age) for up to 15 years.