[Personality profiles of students at risk of dropping out: Resilients, Overcontrollers and Undercontrollers]. / Étudiants à risque de décrochage selon le profil de personnalité : Resilients, Overcontrollers et Undercontrollers.

INTRODUCTION: Preventing students from dropping out of higher education, and particularly university, requires understanding the different factors that can lead to individuals failing to complete their studies. The role of personality in academic success or failure remains poorly understood. Block's personality profile model (Resilients, Overcontrollers, Undercontrollers) has been used to link personality traits to academic performance. The objective of this study is to apply this model to the risk factors of dropping out of higher education courses, including psychological vulnerability, level of autonomy, and the feeling of not being able to keep up. This involved validating Block's profiles in relation to the Big Five personality traits (Extraversion, Agreeableness, Conscientiousness, Neuroticism and Openness), and their links with the risk factors for dropping out. METHODS: This study is based on a quantitative survey of 196 students (mean age 21.32 years±3.11 years, with 63% females) taking higher education courses in France. Three measuring instruments were used: a French scale of Autonomy-situnomy, the French version of the Big Five Inventory (BFI-Fr) for personality traits, and the French version of the General Health Questionnaire (GHQ-28) for psychiatric morbidity. One item empirically evaluated the feeling of not being able to keep up. Data was processed using a k-average cluster analysis to establish the personality profiles, then by analysis of variance measures to evaluate the differences between them, and Bravais-Pearson correlation coefficient to identify links between risk factors and profiles. RESULTS: Conscientiousness (Control) was the trait most strongly associated with high autonomy and a low feeling of not being able to keep up. There was also a positive influence of Extraversion and Agreeableness on autonomy. On the other hand, Neuroticism scores were related to greater psychiatric morbidity, a greater feeling of not keeping up, and lower autonomy. The results for personality profiles confirm the stability of Block's profiles (Resilients, Overcontrollers and Undercontrollers) and their relevance in higher education contexts. Resilients and Overcontrollers had greater autonomy and a lower feeling of not keeping up, but Resilients had the lowest psychiatric morbidity. Undercontrollers were associated with the greatest risk factors: lowest autonomy, the highest psychiatric morbidity and the strongest feeling of not keeping up. Gender comparisons indicated that women were more affected by psychiatric morbidity, but had higher Conscientiousness and autonomy.

Decrease in ovalbumin-induced pulmonary allergic response by benzaldehyde but not acetaldehyde exposure in a Guinea pig model.

The pulmonary effects of two environmentally relevant aldehydes were investigated in nonsensitized or ovalbumin (OA)-sensitized guineapigs (GPs). Four-week-old male Hartley GPs, weighing about 400 g, were intraperitoneally injected with 1 ml of an NaCl solution containing 100 microg OA and 100 mg Al(OH)(3). They were then exposed to either acetaldehyde (200 ppb) or benzaldehyde (500 ppb) for 4 wk (6 h/d, 5 d/wk). At the end of exposure, GPs were challenged with an OA aerosol (0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL). Sensitized nonexposed GPs showed bronchial hyperresponsiveness to OA and an increased number of eosinophils in blood and BAL, together with a rise in total protein and leukotrienes (LTB(4) and LTC(4)/D(4)/E(4)) in BAL. In nonsensitized GPs, exposure to acetaldehyde or benzaldehyde did not induce any change in the tested parameters, with the exception of irritation of the respiratory tract as detected by histology and an increased number of alveolar macrophages in animals exposed to acetaldehyde. In sensitized GPs, exposure to acetaldehyde induced a moderate irritation of the respiratory tract but no change in biological parameters linked to the inflammatory and allergic responses. In contrast, exposure to benzaldehyde induced a decrease both in OA-induced bronchoconstriction and in eosinophil and neutrophil numbers in BAL, an increase in the bronchodilatator mediator prostaglandin E(2) (PGE(2)), and a decrease in the bronchoconstrictor mediators LTC(4)/D(4)/E(4). Further investigations are needed to determine if the attenuated response observed in sensitized GPs exposed to benzaldehyde is due to an alteration of the mechanism of sensitization or to a more direct effect on various mechanisms of the allergic response.

An attempt to evaluate lung aggression in monkey silicosis: hydrolases, peroxidase and antiproteases activities in serial bronchoalveolar lavages.

Exposure to silica can induce fibrosis and/or emphysema. Various factors such as proteases, other hydrolases and oxidants may be involved in the destruction of lung parenchyma. On the other hand, antiproteases play an important role in the protection of lung parenchyma against the action of proteases. We have developed an animal model of silicosis in monkey Macacus cynomolgus and followed these factors by bronchoalveolar lavage (BAL). We have studied glycosidases activities, elastase-like activity, immunoreactive alpha 1-protease inhibitor (alpha 1PI), neutrophil elastase inhibitory capacity (NEIC) and myeloperoxidase. Bronchoalveolar cells in serial BAL were also studied. Six monkeys were exposed to quartz aerosols (100 mg.m-3) for 18 wks. They were followed until they developed X-ray changes, which occurred between 21-64 wks after the end of the dust exposure. Cellular "silicotic nodules" were observed in lung biopsies. A control animal underwent serial BAL. Changes were seen in the differential cell count. The release of superoxide anion by bronchoalveolar cells obtained during the experiment was increased. Separation on a gradient of Percoll showed the presence of young macrophages, which exhibited enhanced release of superoxide anion as compared to the totality of bronchoalveolar cells. The biochemical analysis of BAL fluids obtained during and after the period of dust exposure showed an increase in glycosidases, alpha 1PI and NEIC. Some free elastase-like activity was simultaneously detected in BAL fluids from exposed animals but not from the control. This elastase-like activity was very low compared to NEIC. The increase in enzymatic and antiprotease activities occurred at different points in time for each animal, suggesting large differences in individual responses to dust, but occurred before the chest X-ray abnormalities.

[Visual potentials evoked by a pattern reversal checkerboard in 50 depressed patients]. / Etude des potentiels évoqués visuels par damiers alternants chez 50 patients déprimés.

The pertinency of the visual evoked potentials (VEP) was studied as an index of depression in a group of 50 depressed patients (according to DSM III criteria). The VEP recordings were realized before an antidepressive treatment (D0) and 4 weeks after the beginning of the treatment (D28). Identical recordings were realized with 15 healthy and voluntary reference subjects. Stimulations were reversal checkerboard. The analysis of the results indicate at D0 a reduction of P1 and N1 latencies in the depressed people compared to the reference subjects, and an increase of the P1-N1 amplitude. These differences disappear at D28 (after the antidepressive treatment), as we don't notice any significative difference between D0 and D28 with the reference subjects. The interpretation of these results leads to the hypothesis of a neurophysiological modification of the attentional processes during the depression state. The antidepressive treatment seems merely to produce a normalization of the evoked responses in the depressed patients.

Comparison of hydrolases, peroxidase and protease inhibitors in bronchoalveolar fluid from Macacus cynomolgus and human controls.

1. Serial bronchoalveolar lavages were performed on a subhuman primate (Macacus cynomolgus) in order to give an experimental model for silicosis. 2. We have measured glycosidases, proteases, peroxidase and antiproteases of the BAL fluids from seven normal monkeys. 3. The results obtained were similar to those found in human control BAL fluids. 4. For monkeys, the repetition of the bronchoalveolar procedure does not seem to have an important influence on the values obtained. 5. The present results will now permit sequential follow up studies during the course of experimental silicosis.

[Multidisciplinary approach to depression. Preliminary results]. / Approche multidisciplinaire de la dépression. Résultats préliminaires.

In the present study, clinical interview, Visual Evoked Potentials, psychological tests, TRH test, plasmatic MHPG dosage were investigated in 30 depressed patients with major depressive disorders. All the explorations were realised before and after 28 days of an antidepressant treatment. Thanks to analysis we found out the value of psychological tests. The study of evoked potentials brings to light the existence of electrophysiological variables, subordinate to the clinical state. On the contrary, "TRH Test" does not give us any useful indication, and plasmatic MOPEG dosage, although it confirms the existence of two groups of depressed patients, does not suggest any relationship with evolutive types.

[Contribution to the study of event-related potentials in depressed patients]. / Contribution à l'étude des potentiels évenémentiels chez les deprimés.

When we want to quantify an experimentation on an individual presenting behaviour troubles, the problem we are faced with is the relative inadequacy between the techniques that are used and the patient. The aim of this research is a study of the evolution of the differential analysis of power spectra and alteration in the repartition of VEP amplitudes on 18 depressed adults before and after antidepressive treatment. Control in healthy adult volunteers has been realised. The originality of the method used is in the analytical techniques and selected tests. It is difficult to state positively that VEP morphology represents a pertinent criterion in the study of the evolution of a depressed syndrome. But the results which are obtained show a similar evolution between VEP morphology and clinical criterion. This is in conformity with numerous present studies which consider VEP as a pertinent sign in a psychophysiological process.

[Age and photopic and mesopic visual acuity]. / L'âge et les acuités visuelles photopiques et mésopiques.

Visual acuity at high luminance (100 cdm2) and at low luminance (0.8 cdm2) was measured in normal subjects aged between 20 and 50 years. A decrease of visual acuity at Low luminance was noted with increasing age whereas high luminance acuity remained unchanged (20/20). At thirty years of age, low luminance visual acuity was an average of 20/30 decreasing at 40 years to 20/40. Results were confirmed by statistical analysis. A short study with interference fringes, formed by a coherent light (neon-helium laser) produced directly on the retina and thus by-passing optical effects on the eye, suggested that the retina-brain system was responsible for decreased mesopic visual acuity, night myopia or right presbyopia not playing any part in this decrease as suggested by some authors. Consequences of these findings, concerning particularly workers at low luminance such as pilots or drivers, are discussed.

Visually emitted potential and attentional processes.

Visually emitted potentials were recorded during a series of 450 stimulations with a frequency of 1 per second, during which 10% were voluntarily omitted by the experimenter, either regularly or at random. The recordings summed up here show the presence of a potential emitted in the form of a late positive wave (350 ms) preceded by a negative wave (200 ms) when the subject mentally counted the omissions (regular or random). This leads us to believe that the subject's attention is more determinant than the random distribution of omissions.

Visual evoked potentials and sensory dimensions.

Concomitant variations of physical stimulus characteristics and variations of responses elicited in the human adult subject were studied under conditions of adaptation to darkness or light in order to stimulate the B or the D sub-system described by Jung. Temporal processing in these two systems was compared by analysing output variables (VEPs and sensory ratings) in response to a range of electrophysiological and perceptual responses run in parallel: the temporal summation law, which is a basic code in the nervous system, is found to be obeyed in both B and D subsystems. But asymmetries are also observed, indicating specific characteristics of B and D functioning.

[Spectral band analysis in the study of attentional processes: interest of numerical filtrage by bands]. / Contribution de l'analyse fréquentielle par bandes à l'étude des processus attentionnele: intérêt du filtrage numérique par bandes.

This is a study of relationships between cerebral events and visual attentional processes in 28 healthy adult volunteers by means of a spectral analysis method described in this paper. The recorded data make it possible to study the EEG, standard VEPs, VEPs during attention and visual 'emitted' potentials when stimuli were expected but absent. Compared with the methods of summation and unitary analysis, spectral analysis by bands appears very interesting, especially for the study of 'emitted' potentials because it avoids the subjectivity of operators and reduces the number of stimuli. The results obtained show the interest of this simple, reliable and effective method for the detection and objectivation of evoked activities with only a very few (10) stimuli.

["Emitted" cerebral activity and attention processes in a group of schizophrenics. Methodologic problems]. / Activitiés cérébrales "émises" et processus attentionnels chez un groupe de schizophrènes. Problèmes méthodologiques.

This is a study of the relationship between cerebral events and visual attentional processes of schizophrenic patients by means of a spectral analysis method described in this paper. With recorded data it is possible to study the EEG, standard visual evoked potential, visual evoked potention with attention and visual "emitted" potentials when stimuli were expected but absent. Compared with the sommation method and unitary analysis, the spectral analysis method appears very interesting, especially for the study of "emitted" potentials because it avoids the subjectivity of operators and reduces the number of stimulations. The results show the interest of this simple reliable and effective method for the detection and objectivation of evoked activities with only very few (10) stimulations.

[Emitted cerebral activity and attention processes in a group of schizophrenic methodologic problems]. / Activités cérébrales 'émises' et processus attentionnels chez un groupe de schizophrènes. Problèmes méthodologiques.

This is a study of the relationship between cerebral events and visual attentional processes of schizophrenic patients by means of a spectral analysis method described in this paper. With recorded data it is possible to study the EEG, standard visual evoked potential, visual evoked potention with attention and visual 'emitted' potentials when stimuli were expected but absent. Compared with the summation method and unitary analysis, the spectral analysis method appears very interesting, especially for the study of 'emitted' potentials because it avoids the subjectivity of operators and reduces the number of stimulations. The results show the interest of this simple reliable and effective method for the detection and objectivation of evoked activities with only very few (10) stimulations.