Utilisation du test GeneXpert pour le diagnostic de la tuberculose au service des maladies infectieuses du CHNU de Fann

Introduction: Nous avons réalisé ce travail pour montrer notre expérience d’utilisation du GeneXpert et évaluer son apport dans la confirmation du diagnostic de la tuberculose. Méthodes: Etude prospective descriptive et analytique de janvier à Décembre 2013. Résultats: Quatre vingt quatorze patients ont bénéficié du geneXpert pour le dépistage de la tuberculose toute localisation confondue. Le geneXpert avait été positif dans 62% des cas. Les images radiologiques fortement évocatrices de tuberculose était associées à un geneXpert positif dans 25% des cas. La recherche de BAAR réalisée chez 55 patients était positive dans 9 cas (16%). Le geneXpert était positif sur 46 frottis négatif (54%)et dans 89% sur les frottis positifs. La prévalence de la tuberculose extrapulmonaire était de 34%. Le taux de positivité était variable en fonction du type de prélèvement. Deux cas de résistance à la rifampicine ont été détectées. Conclusion: Le geneXpert a été d’un grand apport pour le diagnostic de la tuberculose pulmonaire et extrapulmonaire mais la bacilloscopie reste incontournable.Pan African Medical Journal 2016; 2

Tuberculose intestinale révélée par une occlusion intestinale aigüe au cours d’une réaction paradoxale au traitement anti-tuberculeux chez un patient immunocompétent: à propos d’un cas et revue de la littérature

La tuberculose intestinale représente 3 à 5% de toutes les localisations viscérales. Malgré l'efficacité démontrée des anti-tuberculeux, des cas d'exacerbation du tableau clinique initial ont été décrits à l'initiation du traitement. Ces réactions dites «paradoxales» sont cependant rarement rapportées chez les immunocompétents et beaucoup moins sous forme d'occlusion intestinale. Nous rapportons un cas de tuberculose intestinale révélée par une occlusion intestinale aigüe au cours d'une réaction paradoxale aux anti-tuberculeux. Il s'agit d'un patient de 26 ans, immunocompétent qui a présenté un syndrome occlusif à un mois de traitement d'une tuberculose pleuro-pulmonaire. La tomodensitométrie (TDM) abdominale était en faveur d'une occlusion intestinale grêlique. La laparotomie objectivait une masse intra-péritonéale avec de multiples adhérences. L'examen anatomopathologique de la pièce opératoire était en faveur d'une tuberculose intestinale. L'évolution était favorable après la poursuite du traitement anti-tuberculeux initial

Facteurs associés à la dissociation immunovirologique chez les patients infectés par le VIH-1 sous traitement antirétroviral hautement actif au Centre de Traitement Ambulatoire (CTA) de Dakar

Introduction: L'objectif de ce travail était d'évaluer les différents facteurs associés à la dissociation immunovirologique malgré un traitement antirétroviral hautement actif et efficace.Méthodes: Il s'agissait d'une étude de cohorte historique, descriptive et analytique faite à partir de dossiers de patients infectés par le VIH-1; sous traitement antirétroviral depuis au moins 12 mois, suivis dans la cohorte du CTA de 2001 à 2011 et ayant une charge virale indétectable depuis 6 mois.Résultats: Durant cette période d'étude de 10 ans, la prévalence de la DIV était de 19,3%. Le sexe féminin était prédominant avec un sexe ratio de 1,9. La dissociation immunovirologique a été plus fréquemment rencontrée chez les patients de sexe masculin (29,7% vs 14,1%) avec une différence statistiquement significative (p = 0,00006). L'âge médian était de 44 ans ± 10 ans. Un antécédent de tuberculose a été retrouvé dans environ un tiers des cas (31,4%). La dissociation immunovirologique était significativement plus fréquente chez les patients ayant un antécédent de tuberculose (p = 0,00005). La plupart des patients (68%) était au stade SIDA 3 ou 4 de l'OMS. Les patients ayant une dissociation immunovirologique étaient plus souvent aux stades 3 et 4 de l'OMS (p = 0,0001). La dénutrition a été notée dans plus de la moitié des cas (56,2%) et la dissociation immunovirologique prédominait chez les patients dénutris (p=0,005). Le taux moyen de lymphocytes TCD4+ était de 86,7± 83 cellules / mm3. La dissociation immunovirologique était plus fréquente chez les patients ayant un taux de lymphocytes TCD4 bas à l'initiation avec une différence statistiquement significative (p = 0,00000). En analyse multivariée; Seuls l'âge supérieur ou égal à 43 ans, le taux de CD4 initial < 100 c/mm3 et le sexe masculin étaient significativement associés à cette dissociation immunovirologique.Conclusion: Les principaux facteurs associés à la dissociation immunovirologique étant évalués, d'autres études portant sur ce groupe mériteraient d'être envisagées afin de connaitre l'impact de cette réponse immunologique partielle sur la survenue d'infections opportunistes ou bien la mise en place d'une trithérapie spécifique uniquement dans le but d'avoir une restauration immunologique optimale.Mots clés: Dissociation, immunovirologique, VIH, DakarEnglish Title: Factors associated with immunovirologic dissociation in HIV-1-infected patients under highly active antiretroviral therapy in the Ambulatory Treatment Center (ATC) in DakarEnglish AbstractIntroduction: the objective of this work is to evaluate the different factors associated with immunovirologic dissociation despite highly active and effective antiretroviral treatment.Methods: we conducted a retrospective, cohort, descriptive and analytical study of the medical records of HIV-1 infected patients having received at least 12 months of antiretroviral therapy, followed in the ATC cohort from 2001 to 2011 and with undetectable viral load in the last 6 months.Results: during this 10-year study period, the prevalence of IVD was 19.3%. Female sex was predominant, with a sex ratio of 1.9. Immunovirologic dissociation was more frequent in male patients (29.7% vs 14.1%) with a statistically significant difference (p = 0,00006). The average age was 44 years ± 10 years. A history of tuberculosis was found in about a third of the cases (31.4%). Immunovirologic dissociation was significantly more frequent in patients with a history of tuberculosis (p = 0.00005). Most patients (68%) had AIDS at WHO clinical stages 3 or 4. Patients with immunovirologic dissociation were more often in WHO clinical stages 3 and 4 (p = 0.0001). More than half of the cases (56.2%) were found to be malnourished and immunovirologic dissociation was prevalent in malnourished patients (p=0.005). The mean CD4+ T lymphocytes counts was 86.7± 83 cells / mm3. Immunovirologic dissociation was more frequent in patients with initial low CD4+ T lymphocyte counts and with a statistically significant difference (p = 0.00000). By multivariate analysis, only age greater than or equal to 43 years, CD4 initial counts < 100 c/mm3 and male sex were significantly associated with this immunovirologic dissociation.Conclusion: our study assessed the main factors associated with immunovirologic dissociation. Other studies of this nature would also merit consideration in order to highlight the impact of this partial immune response on the emergence of opportunistic infections or the implementation of a specific tritherapy for the sole purpose of producing fully successful immune restoration.Keywords: Dissociation, immunovirologic, HIV, Daka

Behavioral and modeling studies of eye and head coordination

Moving eyes and head to orient the visual axis to a point of interest is a routine movement for foveate animals. From reading a book to driving a car or playing tennis, we constantly have to change our line of sight in relation with the current activity. At first, the brain must analyze the visual environment to extract the main features linked to the needs of the task. Once the information is extracted and the goal computed, the central nervous system has to control and coordinate adequately the movements of several body parts (eye, head, trunk, etc.) to achieve accurately the task: modify the orientation of the visual axis. This thesis addresses different questions linked to the control of the gaze (gaze = head-in-space + eye-in-head) and the coordination of eye and head movements. Two methodologies were used throughout the thesis to help answering those questions. A first approach used behavioral experiments to generalize previously reported observations, from head-restrained to head-unrestrained condition. In this part, we first studied how human subjects take into account their own movements to update their internal representation of the spatial surroundings. Then we studied how they coordinate eye and head movement while tracking an oscillating target. The second approach was based on novel mathematical models of the head-unrestrained control of movements. The models were developed either to find a consensus about fundamental questions of eye-head coordination or to stress the importance of taking into account the delays of the sensory system in the control.(FSA 3) -- UCL, 201

L'empire colonial belge, avec trois cartes et douze illustrations.

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Saccadic Compensation for Smooth Eye and Head Movements During Head-Unrestrained Two-Dimensional Tracking

Daye PM, Blohm G, Lefevre P. Saccadic compensation for smooth eye and head movements during head-unrestrained two-dimensional tracking. J Neurophysiol 103: 543-556, 2010. First published November 18, 2009; doi: 10.1152/jn.00656.2009. Spatial updating is the ability to keep track of the position of world-fixed objects while we move. In the case of vision, this phenomenon is called spatial constancy and has been studied in head-restraint conditions. During head-restrained smooth pursuit, it has been shown that the saccadic system has access to extraretinal information from the pursuit system to update the objects' position in the surrounding environment. However, during head-unrestrained smooth pursuit, the saccadic system needs to keep track of three different motor commands: the ocular smooth pursuit command, the vestibuloocular reflex (VOR), and the head movement command. The question then arises whether saccades compensate for these movements. To address this question, we briefly presented a target during sinusoidal head-unrestrained smooth pursuit in darkness. Subjects were instructed to look at the flash as soon as they saw it. We observed that subjects were able to orient their gaze to the memorized (and spatially updated) position of the flashed target generally using one to three successive saccades. Similar to the behavior in the head-restrained condition, we found that the longer the gaze saccade latency, the better the compensation for intervening smooth gaze displacements; after about 400 ms, 62% of the smooth gaze displacement had been compensated for. This compensation depended on two independent parameters: the latency of the saccade and the eye contribution to the gaze displacement during this latency period. Separating gaze into eye and head contributions, we show that the larger the eye contribution to the gaze displacement, the better the overall compensation. Finally, we found that the compensation was a function of the head oscillation frequency and we suggest that this relationship is linked to the modulation of VOR gain. We conclude that the general mechanisms of compensation for smooth gaze displacements are similar to those observed in the head-restrained condition

Catch-up saccades in head-unrestrained conditions reveal that saccade amplitude is corrected using an internal model of target movement

This study analyzes how human participants combine saccadic and pursuit gaze movements when they track an oscillating target moving along a randomly oriented straight line with the head free to move. We found that to track the moving target appropriately, participants triggered more saccades with increasing target oscillation frequency to compensate for imperfect tracking gains. Our sinusoidal paradigm allowed us to show that saccade amplitude was better correlated with internal estimates of position and velocity error at saccade onset than with those parameters 100 ms before saccade onset as head-restrained studies have shown. An analysis of saccadic onset time revealed that most of the saccades were triggered when the target was accelerating. Finally, we found that most saccades were triggered when small position errors were combined with large velocity errors at saccade onset. This could explain why saccade amplitude was better correlated with velocity error than with position error. Therefore, our results indicate that the triggering mechanism of head-unrestrained catch-up saccades combines position and velocity error at saccade onset to program and correct saccade amplitude rather than using sensory information 100 ms before saccade onset

Target motion direction influence on tracking performance and head tracking strategies in head-unrestrained conditions

We examined subjects' behavior when they tracked periodic oscillating targets moving along a randomly oriented ramp with the head free to move. This study focuses on the effect of target motion direction on pursuit performance and on head tracking strategies used by human subjects to coordinate eye and head movements. Our analyses revealed that the gaze tracking gain was modulated by both target oscillation frequency and target motion direction. We found that pursuit gain was modulated by the target motion direction: vertical pursuit being less accurate than horizontal pursuit. While gaze tracking was sensitive to target frequency and orientation, head behavior was less modulated by a change of target frequency than by a change of target motion direction. Additionally, subjects had two main strategies for moving their head: They oriented their head to favor rotations around either the head dorsoventral (target motion directions 70 deg). In between, the subjects did not choose a consistent rotation axis for identical target motion directions