Le phénomène de l'intimidation en milieu scolaire : pistes d'intervention pour le counseling de carrière.

De façon générale, l'école se veut source d'enrichissement, de belles découvertes et de création de nouvelles amitiés. Cependant, pour grand nombre d'élèves qui sont victimes d'intimidation en milieu scolaire, ce parcours scolaire se vit dans la peur, l'anxiété et la solitude. Les conséquences vécues auront aussi un impact sur l'orientation professionnelle de ces jeunes, dont l'altération du concept de soi, qui aurait une influence sur le développement de carrière (Super, 1963, dans Bujold, et Gingras, 2000). On parle aussi de l'anxiété qui occuperait un rôle dans l'indécision vocationnelle (Forner, 2007), ainsi que la destruction de relations sociales essentielles pour l'exploration de soi et l'exploration de son environnement (Bluestein et Felsman, 1999), et l'absence de sentiment de sécurité pouvant influencer la prise de décision (Blusstein, Préziozo et Schultheiss, 1995; Hall, Moradi, Tokar et Withrow, 2003, dans Savard, 2008). Par cette analyse, la question de recherche suivante est formulée : quelles sont les pistes d'intervention possibles pour les conseillères et les conseillers d'orientation qui interviennent auprès des élèves victimes d'intimidation en milieu scolaire? Le deuxième chapitre est consacré à la définition des concepts étudiés pour parvenir à répondre à la question de recherche. Au troisième chapitre, la méthodologie permettant d'effectuer le parallèle entre les concepts étudiés et l'intervention en counseling de carrière est présentée. Au quatrième chapitre, les pistes d'intervention possibles pour les conseillères et les conseillers d'orientation sont identifiées. Finalement, en guise de conclusion, il y a l'identification des limites de cet étude et des éléments qu'éclaire cette recherche sur le plan de l'orientation et de la recherche en général, ainsi que les études pouvant s'ensuivre

Comparison of circadian/activity parameters of neuronal specific overexpression (OE) of <i>dHNF4</i> (<i>ELAV-GS-GAL4</i>>UAS-<i>dHNF4</i>) with age-matched controls.

<p>Induction of GAL4 (OE) started at 1 week of age and flies were tested at 3 weeks of age (2 week treatment period) with 200μM of RU486. (<b>A</b>), Day Sleep bout number; (<b>B</b>), Day activity counts (per 12h period); (<b>C</b>), Total activity count (per 24h period); (<b>D</b>), Day activity (min per 12h); (<b>E</b>) Night activity (min per 12h) and (<b>F</b>) Total activity (min per24h)(**p<0.01, ***p<0.001, ****p<0.0001; SEM is indicated with n = 48 flies; Paired Student’s <i>t</i>-test).</p

Forward and Reverse primers used for RT-qPCR experiments.

<p>Forward and Reverse primers used for RT-qPCR experiments.</p

TERT exerts its anti-apoptotic role through regulation of p15INK4B messenger,

<p>a<b>)</b> Western blot analysis of TERT and p15INK4B levels in 10 DIV hippocampal neurons infected with scrambled or shTERT; Tubulin is used as loading control. Note that p15INK4B levels are reduced by TERT downregulation (n = 2). <b>b)</b> Western blot analysis of p15INK4B levels in control 10 DIV hippocampal neurons and infected with p15INK4B shRNA. The reduction in protein content is more than 50% (bar graph on the right, n = 2). <b>c)</b> Tunel assay of 10 DIV hippocampal neurons under control conditions (control) and after infection with an empty vector (vector) or with the shRNA for p15INK4B (shp15INK4B). The bar graph illustrates the significant cell death under this last condition (mean ± the s.d. of three different cultures; * p<0.05).</p

TERT granules contain the mRNA encoding the pro-survival cyclin inhibitor p15INK4B.

<p><b>a)</b> TERT RNA-immunoprecipitation from cells under control or arsenite-induced stress: immunoprecipitated RNA was used for RT-PCR with specific primers for cell cycle regulators. Note that the only positive amplification product corresponds to the p15INK4B messenger, in the control but not stressed neurons (n = 2). <b>b) Upper panel.</b> p15INK4B in situ hybridization, negative control (anti-sense) and p15INK4B specific probe. Only the specific probe gives a signal, in the nucleus (DAPI positive) and in the cytoplasm. <b>Lower panel.</b> p15INK4B in situ hybridization (red) together with TERT immunofluorescence microscopy (green); nuclear labeling with DAPI (blue). Colocalization is evident in the perinuclear region (arrows in overlay image, “merge”) (n = 3). <b>c)</b> p15INK4B mRNA levels in 10 DIV hippocampal neurons in culture, under control or arsenite treatment. Arsenite does not result in degradation of the messenger (n = 3). <b>d)</b> Representative A254 gradient profile of control (Ctr) and arsenite stressed neurons (Ars); translational efficiency of p15INK4B mRNA was normalized to Histone 3 and β-actin (beta-actin) mRNA, as measured by RT-qPCR assay, using the following algorithm: 2-[ΔCt(P)- ΔCt(mRNPs)]. Stress induces p15INK4B translocation to the polysomes, reflecting higher translation. Standard errors are shown (n = 3). <b>e)</b> Western blot analysis of p15INK4B from 10 DIV hippocampal neurons in culture, in control and in neurons treated with arsenite. Tubulin is used as loading control. Note that arsenite increases the levels of p15INK4B. Bar graph on the right is the quantification of this experiment (means ± the s.d. of three different cultures; *p<0.05).</p

TERT associates to TIA1 –positive granules.

<p><b>a)</b> Western blot analysis of TERT immunoprecipitated proteins in extracts from hippocampal neurons maintained <i>in vitro</i> for 10 DIV, under basal stress conditions (control) or stressed with arsenite. Note that the two SG markers (TIA1 and P-elF2α) are precipitated whereas LSM-1, a component of PBs is not. RNase treatment does not affect TERT-TIA1 binding (n = 4). <b>b)</b> Western blot analysis of TERT immunoprecipitated proteins in extracts from old mice. As in the <i>in vitro</i> experiments, TIA1 and P-elF2α are precipitated whereas LSM-1 is not (n = 3). <b>c)</b> Western blot analysis of TIA1 immunoprecipitated proteins in extracts from hippocampal neurons maintained <i>in vitro</i> for 10 DIV, under basal stress conditions (control) or stressed with arsenite. Again, RNase treatment does not affect TERT-TIA1 binding (n = 4). <b>d)</b> Western blot analysis of TIA1 immunoprecipitated proteins in extracts from old mice. Note that TIA1 and P-elF2α are precipitated whereas LSM-1 is not (n = 3). <b>e)</b> The known TIA1 target ß-actin mRNA is amplified in RNA purified from TERT immunoprecipitate, whereas another known TIA1 target, Caspase-7, is not. The first lane corresponds to the markers (n = 2). <b>f)</b> Confocal microscopy images of neurons double labeled TERT (green)-TIA1 (red) (upper row) and TERT (green)-PABP (red) (lower row). Numerous foci of colocalization exist (quantified in the bar graph: mean ± the s.d. from three different experiments). Scale bar: 10 µm. <b>g)</b> Confocal microscopy images of neurons infected with scrambled or shTERT, stained for TERT (red) and counterstained for TIA1 (blue). The reduction in TIA1 labeling is not significant (mean ± the s.d. from three different experiments). Scale bar: 10 µm.</p

Effect of pillar contact on N-cadherin distribution.

<p>(<b>A</b>) Example of a neuron with the soma covering at least one pillar at 1 hour in culture, immunostained for N-cadherin (GC-4). Its N-cadherin crescent is oriented towards the pillar contacts. For 0.6–1 n = 112, 1.2–2 n = 115, 2.4–7 n = 67. (<b>B</b>) Example of a neuron with the soma touching the pillars 1 hour in culture. The N-cadherin crescent is in the process of being recruited towards the pillar contact.*, significantly different from random (dashed line, 50% for random positioning) using X²-test (p<0.05), ^# indicates p<0.1.For 0.6–1 n = 68, 1.2–2 n = 58, 2.4–7 n = 109. Green: CMFDA Cell tracker, Blue: Hoechst. Scale bars are 5 µm.</p

Substrate Topography Determines Neuronal Polarization and Growth <i>In Vitro</i>

<div><p>The establishment of neuronal connectivity depends on the correct initial polarization of the young neurons. <i>In vivo</i>, developing neurons sense a multitude of inputs and a great number of molecules are described that affect their outgrowth. <i>In vitro,</i> many studies have shown the possibility to influence neuronal morphology and growth by biophysical, i.e. topographic, signaling. In this work we have taken this approach one step further and investigated the impact of substrate topography in the very early differentiation stages of developing neurons, i.e. when the cell is still at the round stage and when the first neurite is forming. For this purpose we fabricated micron sized pillar structures with highly reproducible feature sizes, and analyzed neurons on the interface of flat and topographic surfaces. We found that topographic signaling was able to attract the polarization markers of mouse embryonic neurons -N-cadherin, Golgi-centrosome complex and the first bud were oriented towards topographic stimuli. Consecutively, the axon was also preferentially extending along the pillars. These events seemed to occur regardless of pillar dimensions in the range we examined. However, we found differences in neurite length that depended on pillar dimensions. This study is one of the first to describe in detail the very early response of hippocampal neurons to topographic stimuli.</p></div

Axon position for neurons sensing topography.

<p>(<b>A</b>) Examples of axon position for neuronal soma touching the pillars (left) and covering at leat one pillar (right) (green: tau-1 axon specific staining, red: MAP-2 dendrite specific staining, blue: Hoechst). (<b>B</b>) Axon position analysis for both touching and covering conditions. (<b>C</b>) Golgi position analysis for both touching and covering conditions (dashed line, 25% for random positioning).*, significantly different from random. For ‘soma on interface’, 0.6–1 n = 16, 1.2–2 n = 32, 2.4–7 n = 23. For ‘soma touching’, 0.6–1 n = 16, 1.2–2 n = 41, 2.4–7 n = 28.</p

Substrate Lay-out.

<p>(<b>A</b>) The substrate consisted of individual areas decorated with pillars of different dimensions. The pillar width ranged from 1–5.6 µm (1, 1.2, 1.4, 1.6, 1.8, 2, 2.4, 2.8, 4, 5.6 µm) in the vertical direction, while the spacing ranged from 0.6–15 µm (0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2.0, 2.4, 3.2, 4, 5, 7, 10, 15 µm) and the height was kept constant at 3 µm. (<b>B</b>) Scanning electron microscopy images of different width and spacing of pillars. Left is W = 1 µm, S = 1 µm, middle is W = 1.6 µm, S = 1.6 µm, right is W = 5.6 µm, S = 10 µm. Scale bars are 10 µm.</p