Oxygénation des lits capillaires à la papille optique des patients sains et glaucomateux

Le glaucome représente la première cause de cécité irréversible à l’échelle mondiale. C’est une maladie neuro-dégénérative caractérisée traditionnellement par une pression intraoculaire (PIO) élevée, un dommage du nerf optique et un défaut du champ visuel correspondant. En fait, la PIO élevée constitue le facteur de risque central associé au développement du glaucome. Cependant, en dépit d’un contrôle adéquat de la PIO, la maladie continue à progresser chez certains patients. Cela montre qu’il existe d’autres facteurs impliqués dans la pathogenèse du glaucome. Des études récentes indiquent qu’un dérèglement de l’oxygène est associé à son développement. En utilisant une nouvelle technologie multi-spectrale capable de mesurer la saturation en oxygène (SaO2) dans les structures capillaires de la rétine, cette étude tentera de déterminer si un état d’oxygénation anormal pourrait se retrouver à la papille optique des patients souffrant de glaucome. Une meilleure compréhension du rôle de l’oxygène pourrait aider à améliorer le pronostic du glaucome. Les résultats de l’étude indiquent que le facteur de position (supérieure, temporale et inférieure de la papille optique) n’a aucun effet sur la mesure SaO2 ainsi que sa variabilité chez les patients normaux. La comparaison de la SaO2 entre les sujets normaux et glaucomateux ne montre pas de différence statistiquement significative. En conclusion, la SaO2 «normale» mesurée dans les yeux glaucomateux n'exclut pas nécessairement que l'hypoxie ne soit pas impliquée dans la pathogenèse. Au moment de l’étude, la PIO était bien contrôlée par des médicaments topiques, ce qui pourrait influencer l’oxygénation à la papille optique.Glaucoma is the leading cause of irreversible blindness worldwide. Traditionally, open-angle glaucoma was defined as a neurodegenerative disease characterized by high intraocular pressure (IOP), progressive retinal cell death with subsequent visual field loss. Elevated IOP has been identified as one of the major risk factors for glaucomatous optic nerve damage. However, adequate IOP control cannot prevent progression of the disease in all patients suggesting that there are other factors involved in the pathogenesis of glaucoma. Recent studies suggest that hypoxia may contribute to the development of glaucoma. Using a new multi-spectral detection system of oxygen saturation (O2Sa), this study determined whether an abnormal state of oxygenation at the optic disc could be found in glaucoma patients. Knowledge about the influence of the oxygen in glaucoma may help to improve the pronostic of the disease. The results of the study indicate that the position factor (superior, temporal and inferior of the optic nerve head) has no effect on the measurement of O2Sa and its variability in normal patients. Comparing the O2Sa between normal subjects and glaucoma subjects shows no statistically significant difference. In conclusion, the «normal» O2Sa measured in glaucomatous eyes does not necessarily exclude that hypoxia is not involved in the pathogenesis of glaucoma because glaucoma patients were under treatment with topical drops that lowered IOP. These medicines could affect the oxygenation of the optic disc

Geometrically nonlinear isogeometric analysis of laminated composite plates based on higher-order shear deformation theory

In this paper, we present an effectively numerical approach based on isogeometric analysis (IGA) and higher-order shear deformation theory (HSDT) for geometrically nonlinear analysis of laminated composite plates. The HSDT allows us to approximate displacement field that ensures by itself the realistic shear strain energy part without shear correction factors. IGA utilizing basis functions namely B-splines or non-uniform rational B-splines (NURBS) enables to satisfy easily the stringent continuity requirement of the HSDT model without any additional variables. The nonlinearity of the plates is formed in the total Lagrange approach based on the von-Karman strain assumptions. Numerous numerical validations for the isotropic, orthotropic, cross-ply and angle-ply laminated plates are provided to demonstrate the effectiveness of the proposed method

Screening for the main triterpenic acids in Centella asiatica samples from North and South of Vietnam

The optimal conditions for extraction, hydrolyzation and quantitative determination of the total amounts of two main triterpene acids, asiatic acid, and madecassic acid in Centella asiatica by HPLC and column chromatography are described. Using this method the asiatic acid and madecassic acid content of three Centella asiatica samples collected in Sontay City, Namdinh province, and in Ho Chi Minh City have been screened. The result showed that the contents of both triterpenic acids are higher in Sontay sample and in each sample the content of madecassic acid is higher than that of asiatic acid. Keywords. Centella asiatica, asiatic acid, madecassic acid, quantification

Assessment of the results of clinical pharmacists’ interventions on the use of antibiotics at a medical center in Vietnam between 2021 and 2022

Context: The rational use of antibiotics is a priority when antibiotic resistance has become severe. Clinical pharmacists’ interventions can help increase the rate of rational antibiotic use. Aims: To determine the effect of clinical pharmacists’ interventions on the use of antibiotics and factors related to inappropriate antibiotic use in inpatients at the Department of Surgery, Gia Rai Town Medical Center, Vietnam. Methods: An interventional and cross-sectional descriptive study was conducted from January 1, 2021, to June 30, 2022, at the Department of Surgery, Gia Rai Town Medical Center, Vietnam. Results: There were 710 patients (355 patients in pre-intervention and 355 patients in post-intervention) included in this study. The group of antibiotics used the most was beta-lactam (pre- and post-intervention rates were 60.2% and 61.0%, respectively). The parenteral route was the most commonly used (63.9% in pre-intervention and 60.7% in post-intervention). The rationality of the indication increased after the intervention (from 85.7% to 96.2%); the rationality of the dose increased after the intervention (from 90.5% to 95.2%); the rationality of the number of times of use increased after the intervention (from 90.4% to 98.4%); the rationality of the time increased after the intervention (from 94.8% to 95.1%); the general rationality increased after the intervention (from 66.5% to 85.6%). Infections were associated with inappropriate antibiotic use (p<0.05). Conclusions: Effective clinical pharmacists’ interventions helped raise the rate of rational use of antibiotics. Besides, inappropriate antibiotic use was found to be associated with infections, emphasizing the need for targeted interventions in this field

Prediction of Brain Tumor Progression Using Multiple Histogram Matched MRI Scans

In a recent study [1], we investigated the feasibility of predicting brain tumor progression based on multiple MRI series and we tested our methods on seven patients\u27 MRI images scanned at three consecutive visits A, B and C. Experimental results showed that it is feasible to predict tumor progression from visit A to visit C using a model trained by the information from visit A to visit B. However, the trained model failed when we tried to predict tumor progression from visit B to visit C, though it is clinically more important. Upon a closer look at the MRI scans revealed that histograms of MRI scans such as T1, T2, FLAIR etc taken at different times have slight shifts or different shapes. This is because those MRI scans are qualitative instead of quantitative so MRI scans taken at different times or by different scanners might have slightly different scales or have different homogeneities in the scanning region. In this paper, we proposed a method to overcome this difficulty. The overall goal of this study is to assess brain tumor progression by exploring seven patients\u27 complete MRI records scanned during their visits in the past two years. There are ten MRI series in each visit, including FLAIR, T1-weighted, post-contrast T1-weighted, T2-weighted and five DTI derived MRI volumes: ADC, FA, Max, Min and Middle Eigen Values. After registering all series to the corresponding DTI scan at the first visit, we applied a histogram matching algorithm to non-DTI MRI scans to match their histograms to those of the corresponding MRI scans at the first visit. DTI derived series are quantitative and do not require the histogram matching procedure. A machine learning algorithm was then trained using the data containing information from visit A to visit B, and the trained model was used to predict tumor progression from visit B to visit C. An average of 72% pixel-wise accuracy was achieved for tumor progression prediction from visit B to visit C