Acanthamoeba castellanii induces host cell death via a phosphatidylinositol 3-kinase-dependent mechanism

Granulomatous amoebic encephalitis due to Acanthamoeba castellanii is a serious human infection with fatal consequences, but it is not clear how the circulating amoebae interact with the blood-brain barrier and transmigrate into the central nervous system. We studied the effects of an Acanthamoeba encephalitis isolate belonging to the T1 genotype on human brain microvascular endothelial cells, which constitute the blood-brain barrier. Using an apoptosis-specific enzyme-linked immunosorbent assay, we showed that Acanthamoeba induces programmed cell death in brain microvascular endothelial cells. Next, we observed that Acanthamoeba specifically activates phosphatidylinositol 3-kinase. Acanthamoeba-mediated brain endothelial cell death was abolished using LY294002, a phosphatidylinositol 3-kinase inhibitor. These results were further confirmed using brain microvascular endothelial cells expressing dominant negative forms of phosphatidylinositol 3-kinase. This is the first demonstration that Acanthamoeba-mediated brain microvascular endothelial cell death is dependent on phosphatidylinositol 3-kinase

Equally moved and not really sick from viewing 2D and 3D motion stimuli on a TV screen

Objective : Visually induced motion sickness (VIMS) and increased postural sway are two adverse side effects that may occur when viewing motion stimuli. However, whether these effects are elevated to a greater extent when viewing stereoscopic 3D motion stimuli, compared to 2D stimuli on a TV screen, has not been investigated under controlled circumstances. Therefore this study aimed at investigating VIMS and postural sway before, during, and directly after viewing 2D and 3D motion stimuli, on a commonly available TV screen. Method : 16 Participants were exposed to an aviation documentary shown in 2D and in 3D on separate occasions. Before, during, and after exposure, VIMS and postural sway were measured. VIMS was quantified by a rating scale giving a single number, and by a multi-symptom questionnaire that assessed multiple VIMS symptoms separately. Sway path length, standard deviations and short-range and long-range scaling components of the center of pressure were calculated as measures of postural sway. Results : VIMS symptom severity, as obtained with the single rating scale, did not show a significant increase to either 2D or 3D exposure. The multi-symptom questionnaire did reveal significant increases in VIMS symptom severity to both 2D and 3D exposure. However, VIMS was not significantly more increased in case of 3D exposure compared to 2D exposure. All postural sway measures (sway path length, standard deviation in mediolateral and anteroposterior direction, as well as the short-range scaling components) increased significantly as a result of exposure. None of the postural sway measures was differentially affected to 3D as compared to 2D exposure. Conclusion : Viewing 3D motion stimuli did not cause more serious VIMS symptoms, compared to viewing motion stimuli in 2D. We attribute this lack of difference to the fact that the 3D effects in this documentary were optimized for viewing in a cinema, the projection on the TV-screen thus causing quarantining of the visual input. The increase in postural sway, irrespective of image type, may reflect exploratory behavior, allowing the participant to gain more information about self-orientation with respect to the virtual environment

Response interference and working memory in 12-year-old children

A group of 69 12-year-old children performed three well-known response interference tasks: the Stroop task, the Eriksen flanker task, and the Simon task. Individual differences in accuracy and speed correlated across the tasks. However, there was no correlation between the interference effects on these three tasks. Stroop interference, but not the Simon or flanker effect, was correlated with working memory capacity, as obtained from the WISC-R. These results may help clarify the nature of ADHD, which is characterized by problems with response interference

Sara Karlik: la magia del ricordo

Gait initiation (GI) from a quiet bipedal posture has been shown to be influenced by the emotional state of the actor. The literature suggests that the biomechanical organization of forward GI is facilitated when pleasant pictures are shown, as compared to unpleasant pictures. However, there are inconsistencies in the literature, which could be due to the neural dynamics of affective processing. This study aimed to test this hypothesis, using a paradigm whereby participants initiated a step as soon as they saw an affective picture (i.e., onset), or as soon as the picture disappeared from the screen (i.e., offset). Pictures were a priori categorized as pleasant or unpleasant, and could also vary in their arousing properties. We analyzed center-of-pressure and center-of-gravity dynamics as a function of emotional content. We found that gait was initiated faster with pleasant images at onset, and faster with unpleasant images at offset. Also, with offset GI the peak velocity of the COG was reduced, and subjects took smaller steps, with unpleasant images relative to pleasant images. The results are discussed in terms of current knowledge regarding temporal processing of emotions, and its effects on GI