Medicine (RMH) - Research Publications
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ItemEffect of Disease-Modifying Therapy on Disability in Relapsing-Remitting Multiple Sclerosis Over 15 Years(LIPPINCOTT WILLIAMS & WILKINS, 2021-02-02)OBJECTIVE: To test the hypothesis that immunotherapy prevents long-term disability in relapsing-remitting multiple sclerosis (MS), we modeled disability outcomes in 14,717 patients. METHODS: We studied patients from MSBase followed for ≥1 year, with ≥3 visits, ≥1 visit per year, and exposed to MS therapy, and a subset of patients with ≥15-year follow-up. Marginal structural models were used to compare the cumulative hazards of 12-month confirmed increase and decrease in disability, Expanded Disability Status Scale (EDSS) step 6, and the incidence of relapses between treated and untreated periods. Marginal structural models were continuously readjusted for patient age, sex, pregnancy, date, disease course, time from first symptom, prior relapse history, disability, and MRI activity. RESULTS: A total of 14,717 patients were studied. During the treated periods, patients were less likely to experience relapses (hazard ratio 0.60, 95% confidence interval [CI] 0.43-0.82, p = 0.0016), worsening of disability (0.56, 0.38-0.82, p = 0.0026), and progress to EDSS step 6 (0.33, 0.19-0.59, p = 0.00019). Among 1,085 patients with ≥15-year follow-up, the treated patients were less likely to experience relapses (0.59, 0.50-0.70, p = 10-9) and worsening of disability (0.81, 0.67-0.99, p = 0.043). CONCLUSION: Continued treatment with MS immunotherapies reduces disability accrual by 19%-44% (95% CI 1%-62%), the risk of need of a walking aid by 67% (95% CI 41%-81%), and the frequency of relapses by 40-41% (95% CI 18%-57%) over 15 years. This study provides evidence that disease-modifying therapies are effective in improving disability outcomes in relapsing-remitting MS over the long term. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that, for patients with relapsing-remitting MS, long-term exposure to immunotherapy prevents neurologic disability.
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ItemNo Preview AvailableCoronavirus Disease 2019 (COVID-19) in Conakry, Republic of Guinea: Analysis and Relationship with Meteorological Factors(Scientific Research Publishing, Inc., 2021)
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ItemAnalysis of Rainfall Dynamics in Conakry, Republic of Guinea(Scientific Research Publishing, Inc., 2020)
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ItemHydropluviometric variability in non-Sahelian West Africa: Case of the Koliba/Corubal River Basin (Guinea and Guinea-Bissau)(Copernicus GmbH, 2020-09-15)Abstract. The Koliba/Corubal River watershed is poorly documented due to the hydrometric measurements shutdown and gaps in the very short hydropluviometric timeseries. The purpose of this study is to analyze the variability of rainfall in the Basin, by simulating flows using the GR2M rain-flow model and extending the discharge timeseries. From the regional vector method, the rainfall timeseries were homogenized, and the gaps filled by the estimated values. The rank correlation and Pettitt test on annual rainfall amounts (1924–2015) indicate breaks in 1958, 1967 and 1969, leading to rainfall deficits ranging from 9.7 % to 20.2 %. For some stations, the segmentation method shows a recovery of rainfall towards the end of the 1980s (Gaoual, Mali) and the early 2000s (Gabu). The analysis of the temporal distribution of the Monthly Rainfall Coefficients shows an improvement of the contributions of a few months during the period after rupture. From a hydrological point of view, the correlation between the mean annual rainfall and the runoff has allowed to extend the flow timeseries. The mean monthly rainfall calculated using the inverse square of distance method, the Potential Evapotranspiration, and the flow rates were used to calibrate and validate the model to determine the parameters that better transform rainfall in flow. The values of the Nash criteria close to 100 have made it possible to extend the monthly flow data from Koliba/Corubal to Gaoual, Cade and Tche-Tche until 2015.
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ItemNo Preview AvailableImpact of different heat wave definitions on daily mortality in Bandafassi, Senegal.(Public Library of Science (PLoS), 2021)OBJECTIVE: The aim of this study is to find the most suitable heat wave definition among 15 different ones and to evaluate its impact on total, age-, and gender-specific mortality for Bandafassi, Senegal. METHODS: Daily weather station data were obtained from Kedougou situated at 17 km from Bandafassi from 1973 to 2012. Poisson generalized additive model (GAM) and distributed lag non-linear model (DLNM) are used to investigate the effect of heat wave on mortality and to evaluate the nonlinear association of heat wave definitions at different lag days, respectively. RESULTS: Heat wave definitions, based on three or more consecutive days with both daily minimum and maximum temperatures greater than the 90th percentile, provided the best model fit. A statistically significant increase in the relative risk (RRs 1.4 (95% Confidence Interval (CI): 1.2-1.6), 1.7 (95% CI: 1.5-1.9), 1.21 (95% CI: 1.08-1.3), 1.2 (95% CI: 1.04-1.5), 1.5 (95% CI: 1.3-1.8), 1.4 (95% CI: 1.2-1.5), 1.5 (95% CI: 1.07-1.6), and 1.5 (95% CI: 1.3-1.8)) of total mortality was observed for eight definitions. By using the definition based on the 90th percentile of minimum and maximum temperature with a 3-day duration, we also found that females and people aged ≥ 55 years old were at higher risks than males and other different age groups to heat wave related mortality. CONCLUSION: The impact of heat waves was associated with total-, age-, gender-mortality. These results are expected to be useful for decision makers who conceive of public health policies in Senegal and elsewhere. Climate parameters, including temperatures and humidity, could be used to forecast heat wave risks as an early warning system in the area where we conduct this research. More broadly, our findings should be highly beneficial to climate services, researchers, clinicians, end-users and decision-makers.
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ItemNo Preview AvailableElectro-generation of hydrogen peroxide using a graphite cathode from exhausted batteries: study of influential parameters on electro-Fenton process(TAYLOR & FRANCIS LTD, 2020-05-11)In this work, the study of hydrogen peroxide (H2O2) electro-generation using graphite from exhausted batteries (Gr-Bat) was conducted. Linear sweep voltammetry and electrolysis experiments were carried out in a single compartment electrochemical cell. Study of the possibility to use this electrode revealed that it presents, as vitreous carbon (VC) electrode, a reduction of oxygen with two successive waves (bi-electronic reduction). The first wave corresponds to the reduction of O2 to H2O2, while the second one corresponds to the reduction of H2O2 to H2O. The cathodic potentials for electro-generation of H2O2 appeared at -600 and -700 mV vs. Ag/AgCl for Gr-Bat and VC electrodes, respectively. Subsequently, electrolysis experiments were conducted by imposing the potentials required for H2O2 formation. The effect of several operating parameters on H2O2 production, such as the nature and concentration of the electrolyte, the pH, the presence of ferrous ions and O2 injection were studied using Gr-Bat and VC electrodes, respectively. For both electrodes, the acidic medium was more favorable for H2O2 electro-generation. The oxygen injection in solution promoted an increase of H2O2 concentration, but its effect was more pronounced in the case of VC electrode. Application for crystal violet degradation by electro-Fenton revealed that Gr-Bat had the best purification performance. A removal rate of 73.18% was obtained with Gr-Bat electrode against 62.27% with VC electrode for an electrolysis time of 120 min. This study has demonstrated the possibility of recycling Gr-Bat by using them as cathode materials in the electro-Fenton process.
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ItemIntegration of QTL, Transcriptome and Polymorphism Studies Reveals Candidate Genes for Water Stress Response in Tomato(MDPI, 2020-08)Water deficit (WD) leads to significant phenotypic changes in crops resulting from complex stress regulation mechanisms involving responses at the physiological, biochemical and molecular levels. Tomato growth and fruit quality have been shown to be significantly affected by WD stress. Understanding the molecular mechanism underlying response to WD is crucial to develop tomato cultivars with relatively high performance under low watering conditions. Transcriptome response to WD was investigated through the RNA sequencing of fruit and leaves in eight accessions grown under two irrigation conditions, in order to get insight into the complex genetic regulation of WD response in tomato. Significant differences in genotype WD response were first observed at the phenotypic level for fruit composition and plant development traits. At the transcriptome level, a total of 14,065 differentially expressed genes (DEGs) in response to WD were detected, among which 7393 (53%) and 11,059 (79%) were genotype- and organ-specific, respectively. Water deficit induced transcriptome variations much stronger in leaves than in fruit. A significant effect of the genetic background on expression variation was observed compared to the WD effect, along with the presence of a set of genes showing a significant genotype x watering regime interaction. Integrating the DEGs with previously identified WD response quantitative trait loci (QTLs) mapped in a multi-parental population derived from the crossing of the eight genotypes narrowed the candidate gene lists to within the confidence intervals surrounding the QTLs. The results present valuable resources for further study to decipher the genetic determinants of tomato response to WD.
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ItemBrain iron is associated with accelerated cognitive decline in people with Alzheimer pathology(SPRINGERNATURE, 2020-11)Cortical iron has been shown to be elevated in Alzheimer's disease (AD), but the impact of the directly measured iron on the clinical syndrome has not been assessed. We investigated the association between post-mortem iron levels with the clinical and pathological diagnosis of AD, its severity, and the rate of cognitive decline in the 12 years prior to death in subjects from the Memory and Aging Project (n = 209). Iron was elevated (β [SE] = 9.7 [2.6]; P = 3.0 × 10-4) in the inferior temporal cortex only in subjects who were diagnosed with clinical AD during life and had a diagnosis of AD confirmed post-mortem by standardized criteria. Although iron was weakly associated with the extent of proteinopathy in tissue with AD neuropathology, it was strongly associated with the rate of cognitive decline (e.g., global cognition: β [SE] = -0.040 [0.005], P = 1.6 × 10-14). Thus, cortical iron might act to propel cognitive deterioration upon the underlying proteinopathy of AD, possibly by inducing oxidative stress or ferroptotic cell death, or may be related to an inflammatory response.