Prévalence et facteurs de risque du surpoids et de l’obésité dans une population d’enfants scolarisés en milieu urbain à Sfax, Tunisie

Introduction: L'objectif de ce travail etait d'étudier la prévalence du surpoids et de l'obésité chez un  groupe d'enfants d'âge scolaire, habitant la ville de Sfax en Tunisie, et identifier les facteurs favorisant la prise pondérale. Méthodes: Il s'agossait d'une enquête descriptive transversale était réalisée en 2011 sur un échantillon représentatif d'élèves recrutés dans 11 écoles primaires publiques. Des informations  concernant les caractéristiques sociodémographiques, les habitudes alimentaires et le comportement sédentaire pour chaque élève ont été précisées au moyen d'un questionnaire. Résultats: Nous avons colligé 1529 élèves, âgés entre 9 et 12 ans et se répartissant en 787 garçons (51,14%) et 747 filles (48,86%). Selon les seuils de  référence de l'IOTF, la fréquence de l'obésité était de 2,4% et celle du surpoids était de 6,3%. L'obésité était significativement associée à l'obésité parentale, un niveau socioéconomique élevé, la prise de plus de deux goûters par jour et à l'activité sédentaire. Conclusion: L'identification des facteurs de risque du surpoids et de l'obésité infantile permettrait de dépister les enfants à risques afin de leur proposer des mesures de prévention adaptées. Ces mesures de prévention devraient inclure non seulement des approches individuelles, mais aussi l'environnement social et physique de l'enfant. Key words: Enfant, obésité, surpoids, facteurs de risque, milieu scolair

Pseudomonas aeruginosa Swarmer Cells Adaptation Toward UVc Radiations

Swarming is the most rapid surface motility allowing Pseudomonas aeruginosa bacteria to rapidly colonize new surfaces. However, swarming behavior is affected by environmental factors like ultraviolet irradiation (UVc). UVc radiation is the most disinfection technology usually applied for wastewater and proven to be effective to inactivate microorganisms. However, efficiency against motile bacteria is not yet studied. This study aims to explain the mechanisms of resistance of swarmer P. aeruginosa cells toward UVc exposure. P. aeruginosa liquid cultures were allowed to swarm across a semisolid surface for 18 h and directly exposed to UVc radiations. Emergent swarmer colonies, revealed after re-incubation, were selected to study biofilm formation, fatty acid (FA) composition, and ultrastructure. Our results showed that membrane adaptation to UVc radiations was seen in Pseudomonas cells by an increase of cyclic fatty acid (CFA) content, confirming the role of cyclopropane in radio-resistance of swarmer cells. Furthermore, electron microscopic study confirmed that over production of S-layer is believed to be a protective form adopted by P. aeruginosa swarmer cells to resist after 5 min of UVc exposure. Moreover, membrane disintegration is the lethal effect observed after 15 min of UVc exposure. In the other hand, study of biofilm production showed an enhancement of biofilm formation, of swarmer cells mainly after 15 min of UVc exposure. There results confirmed that swarming process is highly correlated with particular FA composition of P. aeruginosa membrane and that radio-resistance of swarmer cells is highly supported by CFA biosynthesis and S-layer overproduction

The role of ultrasound guided peri-tendinous injection in the treatment of non-calcific tendinopathy

Purpose: To evaluate the effectiveness of the percutaneous ultrasound guided peri-tendinous injection in improving or treating non-calcific tendinopathy. Patients and methods: Between January 2012 and March 2014, 25 patients with non calcific tendinosis were treated by ultrasound guided corticosteroid injection. All patients underwent pre-treatment diagnostic ultrasound, as well as assessment of the pain and disability of the affected area through a self-answered questionnaire. Reevaluation of the ultrasound changes and clinical response as regard the pain and disability score on regular follow up visits, were done at the 1st, 3rd and 6th month posttreatment. Results: According to the results of this study, there was statistically marked reduction in patients pain and disability score, with reduction of the mean pain score from maximum 3 points pre-treatment to 0.5 post-treatment, and mean disability score form 1.5 point pre-treatment to 0 point at the 6th month follow up visit. The clinical success rate was 87%, with a technical success rate of 100%. Conclusion: Ultrasound is a non invasive imaging technique that allows real time guidance for interventional therapy of non-calcific tendinopathy improving the result of peri-tendinous corticosteroid injection

Role of quantitative diffusion weighted

Purpose: To evaluate the diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions. Patients and methods: Forty patients with positive diagnoses at mammography or breast ultrasound were included in this study. Patients were imaged with dynamic contrast enhanced MRI and DWI before biopsy of their breast tumors. Apparent diffusion coefficient (ADC) map was utilized to select the region of interest (ROI) for ADC calculation. DWI was performed using three sets of b value (0, 400, and 800 s/mm2). Results: The final analysis comprised 40 breast lesions, 18 of which were malignant and 22 were benign. Significant results were obtained between ADC values of benign and malignant lesions (p < 0.001). The cut-off ADC value for benign and malignant lesions was 1.25 × 10–3 mm2/s. Conclusion: The present study provides consistent evidence to support DWI as a diagnostic tool for breast lesion characterization and as a useful adjunct to standard breast MRI protocols in aiding the diagnosis of breast cancer

Quantitative chemical-shift MR imaging cutoff value: Benign versus malignant vertebral compression – Initial experience

Purpose: To evaluate the diagnostic accuracy of in-phase/opposed-phase quantitative chemical shift magnetic resonance (MR) imaging of the spine and to determine the cutoff value that enables differentiation of malignant from benign compression fractures, in patients with known primary malignancy. Patients and methods: Prospective assessment of thirty-two patients with known primary malignancy who presented with vertebral compression fractures, MR imaging of the spine at 1.5 Tesla with standard conventional MR sequences and additional chemical shift (in-phase/opposed-phase) imaging was done. Quantitative image analysis by drawing regions of interest (ROI) on the abnormal marrow of compressed (study group) and adjacent normal vertebra (control group) was also performed in each patient. The signal intensity ratio (SIR) of the marrow was determined by dividing the mean signal intensity on the opposed-phase to the mean signal intensity on the in-phase images and statistical analysis was performed. Results: Mean SIR of benign vertebral compression [0.73 ± 0.07 (range 0.12–1.2)] was significantly lower than malignant SIR values [1.72 ± 0.14 (range 0.8–2.96)] (p < 0.0001; area under the ROC curve, 0.97). The optimal SIR cutoff value for separating benign and malignant vertebral compression was found to be 0.91 with a calculated sensitivity of 93%, specificity of 82% and accuracy of 88%. Conclusion: Quantitative chemical shift MR imaging could be a valuable addition to standard MR imaging techniques and represent a rapid problem solving tool in differentiating benign from malignant vertebral compression, especially in patients with known primary malignancies

Role of ultrasound elastography in as

Purpose: To evaluate the role of ultrasound elastography as an additional technique in differentiating US indeterminate thyroid nodules in order to decrease the number of tissue biopsies. Methods: We evaluated 30 patients with 36 indeterminate thyroid nodules based on US, criteria, by US elastography, using both the elastography score and strain ratio. Baseband US data were downloaded for off-line analysis. Elastographic maps (color coding) and thyroid stiffness index (strain ratio) were calculated for all nodules, with histopathological results being the standard reference. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff strain ratio for separating benign and malignant thyroid nodules. Results: Malignant nodules had a higher degree of color and strain ratio compared to benign nodules, with a statistically significant difference (p < 0.05). Nodules with an elastography score of 2 were benign, while those with an elastography score of 4 and 5 were mostly malignant. Malignancy could not be excluded using ultrasound elastography criteria only, in nodules with a score of 3. The sensitivity and specificity of the US-elastography strain color coding for thyroid cancer diagnosis were 91% and 72% respectively. Using ROC analysis, the optimal cutoff strain ratio for separating benign and malignant thyroid nodules was found to be 1.6 with a calculated 89% sensitivity and 70% specificity. The overall accuracy of strain color was slightly better than strain ratio, 91% compared to 86% respectively. Conclusion: Ultrasound elastography is an easy, non-invasive and rapid technique that can be routinely used in thyroid US scans to select cases for FNAC, and decrease the number of unnecessary biopsies, and consequently decrease the hazards and costs. However, future advances in image acquisition and reconstruction algorithms are required to improve the image quality and clinical usefulness of this technique

Potential role of quantitative MRI assessment in differentiating high from low-grade gliomas

Background: It is crucial to accurately differentiate HGGs from LGGs, as treatment strategies vary. Our study aims to assess the sensitivity and specificity of fractional anisotropy (FA) values derived from diffusion tensor imaging (DTI) and dynamic contrast enhanced perfusion-weighted imaging (PWI) in differentiating HGGs from LGGs. Materials: 15 patients with HGGs and 9 LGGs were examined. Mean, Minimal and Maximal FA fractional anisotropy in tumour, necrotic area and in surrounding oedema, as well as (rCBV) ratio of the lesions were measured and compared between LGG and HGG. The efficacy of the above parameters in grading gliomas was evaluated. In perfusion MRI, we measure rCBV ratio as parameter of neovascularity of tumour. Results: The use of MR DTI had an important role in the grading of brain gliomas as it was accurate in grading 24 cases. There was significant correlation between histopathological grade and FA values measured in tumour and necrotic areas. No positive correlation in perifocal areas could be established. Our results show significant difference between HGG and LGG with mean rCBV ratio as 2.62 & 0.79 with best cut-off value (1.2). Combined use of MR DTI and MR perfusion added to the accuracy of grading of glioma

A Comparison between Particle Swarm and Grey Wolf Optimization Algorithms for Improving the Battery Autonomy in a Photovoltaic System

This research focuses on a photovoltaic system that powers an Electric Vehicle when moving in realistic scenarios with partial shading conditions. The main goal is to find an efficient control scheme to allow the solar generator producing the maximum amount of power achievable. The first contribution of this paper is the mathematical modelling of the photovoltaic system, its function and its features, considering the synthesis of the step-up converter and the maximum power point tracking analysis. This research looks at two intelligent control strategies to get the most power out, even with shading areas. Specifically, we show how to apply two evolutionary algorithms for this control. They are the “particle swarm optimization method” and the “grey wolf optimization method”. These algorithms were tested and evaluated when a battery storage system in an Electric Vehicle is fed through a photovoltaic system. The Simulink/Matlab tool is used to execute the simulation phases and to quantify the performances of each of these control systems. Based on our simulation tests, the best method is identified