Valeur socio-économique de l’arbre en milieu malinké (Khossanto, Sénégal)

Objectif: Déterminer la valeur socio-économique des ligneux dans la vie des populations de la communauté rurale de Khossanto, dans la partie orientale du Sénégal et apprécier les savoirs et savoir-faire locaux vis-à-vis de l’arbre.Méthodologie et résultats: Des enquêtes ethnobotaniques ont été menés auprès des populations de la communauté rurale de Khossanto. Nous avons recensé les savoirs et savoir-faire des Malinkés vis-à-vis de l’arbre dans six catégories d’usages : alimentation, fourrage, construction, artisanat, énergie domestique et phytothérapie, avec des niveaux de consensus assez élevés (partout supérieur à 80%). Six espèces multi usages (impliquées dans presque toutes les catégories) s’avèrent être les plus utiles : Cordyla pinnata, Borassus aethiopum, Vitellaria paradoxa, Ziziphus mauritiana, Pterocarpus erinaceus et Adansonia digitata. Les fruits (31%), les feuilles (29%) et le bois (22%) sont les parties les plus utilisées.Conclusion et application des résultats: L’importance socio-économique de l’arbre en milieu malinké est clairement établie autour de six catégories d’usage : le fourrage, l’alimentation humaine, l’énergie domestique, la phytothérapie, la construction et l’artisanat. Cette importance des ligneux a pour corollaire un prélèvement assez intense de certaines parties, qui devient une menace pour ces espèces. Il apparaît important d’asseoir un modèle de gestion durable de ces parcours communautaires.Mots clés : Ligneux, usages, importance, Sénégal , Kédougou

Compression medullaire lente secondaire a un lymphome de Burkitt intra - rachidien

Le lymphome de Burkitt (LB) appartient au groupe des lymphomes malins non hodgkiniens (LMNH) à cellules B. Il sévit de façon endémique chez l’enfant africain en région intertropicale. La rareté des localisations neuro-méningées dont médullaires a été rapportée. Nous rapportons le cas d’un jeune garçon présentant une localisation médullaire secondaire de LB maxillo-facial. Il avait présenté de façon lentement progressive dans un contexte d’amaigrissement et de tumeur maxillo-faciale, un syndrome de compression médullaire dorsale dont le diagnostic a été confirmé au myéloscanner dorsal. L’histologie de la tumeur maxillo faciale après biopsie révélait un LB. Une chimiothérapie a permis une disparition complète de la tumeur maxillo-faciale à la fin du 1er mois et une récupération neurologique au bout d’un an. La localisation secondaire intra rachidienne d’un LB bien que rare doit être présente à l’esprit surtout en face d’une compression médullaire lente survenue dans un contexte de tumeur maxillo-faciale chez l’enfant

Détermination du débit de filtration glomérulaire (DFG) au cours du diabète : Cockroft et Gault, MDRD ou CKD-EPI ?

Plusieurs paramètres peuvent être étudiés pour évaluer le rein. Parmi ceux-ci, le débit de filtration glomérulaire (DFG) a été déterminé avec les formules de Cockroft et Gault (CG), du Modification of Diet in Renal Disease (MDRD) et du Chronic Kidney Disease EPIdemiology Collaboration (CKD-EPI) et la formule la mieux adaptée pour le diabétique a été recherchée. Chez 59 diabétiques de type 1 (DT1) et 70 diabétiques de type 2 (DT2), le DFG a été déterminé avec les formules de CG, du MDRD et du CKD-EPI. Avec l’analyse statistique, les seuils de significativité ont été fixés pour p<0,05 ; T0α>1,96 et Z0α>1,96. Le MDRD est superposable au CKD-EPI chez les DT1 et DT2. Chez les DT1, le DFG moyen et la corrélation entre 1/créatininémie et DFG ne varient pas si CG ou CKD-EPI ; cependant, les sujets à DFG réduit (< 90 ml/min/1,73 m²) sont plus nombreux avec CG plutôt qu’avec CKD-EPI (66,10% vs 47,46% ; T0α=2,05). Chez les DT2, le DFG moyen et la proportion de sujets à DFG réduit sont indépendants de la formule utilisée, mais la corrélation entre 1/créatininémie et DFG est plus forte si CKD-EPI que CG (0,961 vs 0,632 ; Z0α=7,02). Ainsi, la formule la mieux adaptée pour la détermination du DFG serait CG chez les DT1 et CKD-EPI chez les DT2, sachant que CKD-EPI est équivalent à MDRD quel que soit le type de diabète.Mots clés : Cockroft et Gault - MDRD - CKD-EPI – débit de filtration glomérulaire (DFG) – diabète

Aggravation de l’anémie et polymorphisme de l’haptoglobine au cours de la drépanocytose au Sénégal

La drépanocytose homozygote s’accompagne d’une augmentation de l’hémoglobine (Hb) plasmatique, susceptible d’exposer les hématies à un stress oxydant. L’haptoglobine présente trois phénotypes majeurs (Hp1-1, Hp 2-1 et Hp 2-2) susceptibles de fixer l’hémoglobine extracellulaire avec une efficacité différente. L’objectif de ce travail est de voir si la connaissance du phénotype d’Hp pouvait constituer un élément prédictifde l’anémie sévère. Pour cela, il a été recruté 68 drépanocytaires  homozygotes, âgés de 5 à 31 ans. Pour chaque patient, un témoin de même sexe et de même âge ± 2 ans a été recruté. Le phénotypage de l’Hp a été réalisé par électrophorèse sur gel de polyacrylamide. Les résultats du dosage de l’Hb font ressortir que les taux d’Hb sont significativement différentes chez les patients comparées à celles des témoins (p = 0,001). Lorsque la répartition a été faite en fonction du phénotype d’Hp, une différence statistiquement significative a étéretrouvée entre le phénotype Hp1-1 et le phénotype Hp2-2 (p < 0,001) chez les patients et non chez les témoins. Les résultats de cette étude préliminaire suggéreraient que la connaissance du phénotype d’Hp seraitun facteur prédictif de l’anémie sévère au cours de la drépanocytose.Mots clés : Drépanocytose, anémie, phénotypes d’haptoglobine

Strengthening human genetics research in Africa: report of the 9th meeting of the African Society of Human Genetics in Dakar in May 2016.

The 9th meeting of the African Society of Human Genetics, in partnership with the Senegalese Cancer Research and Study Group and the Human Heredity and Health in Africa (H3Africa) Consortium, was held in Dakar, Senegal. The theme was Strengthening Human Genetics Research in Africa. The 210 delegates came from 21 African countries and from France, Switzerland, UK, UAE, Canada and the USA. The goal was to highlight genetic and genomic science across the African continent with the ultimate goal of improving the health of Africans and those across the globe, and to promote the careers of young African scientists in the field. A session on the sustainability of genomic research in Africa brought to light innovative and practical approaches to supporting research in resource-limited settings and the importance of promoting genetics in academic, research funding, governmental and private sectors. This meeting led to the formation of the Senegalese Society for Human Genetics

Antibiotic Treatment of the Tick Vector Amblyomma americanum Reduced Reproductive Fitness

BACKGROUND: The lone star tick Amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern United States. A Coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected A. americanum. The Coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a Rickettsia sp. was less prevalent and in lower densities when present. METHODOLOGY/PRINCIPAL FINDINGS: We manipulated the numbers of both bacterial species in laboratory-reared A. americanum by injecting engorged nymphs or engorged, mated females with single doses of an antibiotic (rifampin or tetracycline) or buffer alone. Burdens of the bacteria after molting or after oviposition were estimated by quantitative polymerase chain reaction with primers and probes specific for each bacterial species or, as an internal standard, the host tick. Post-molt adult ticks that had been treated with rifampin or tetracycline had lower numbers of the Coxiella sp. and Rickettsia sp. and generally weighed less than ticks that received buffer alone. Similarly, after oviposition, females treated previously with either antibiotic had lower burdens of both bacterial species in comparison to controls. Treatment of engorged females with either antibiotic was associated with prolonged time to oviposition, lower proportions of ticks that hatched, lower proportions of viable larvae among total larvae, and lower numbers of viable larvae per tick. These fitness estimators were associated with reduced numbers of the Coxiella sp. but not the Rickettsia sp. CONCLUSION/SIGNIFICANCE: The findings indicate that the Coxiella sp. is a primary endosymbiont, perhaps provisioning the obligately hematophagous parasites with essential nutrients. The results also suggest that antibiotics could be incorporated into an integrated pest management plan for control of these and other tick vectors of disease

First-principles quantum transport modeling of spin-transfer and spin-orbit torques in magnetic multilayers

We review a unified approach for computing: (i) spin-transfer torque in magnetic trilayers like spin-valves and magnetic tunnel junction, where injected charge current flows perpendicularly to interfaces; and (ii) spin-orbit torque in magnetic bilayers of the type ferromagnet/spin-orbit-coupled-material, where injected charge current flows parallel to the interface. Our approach requires to construct the torque operator for a given Hamiltonian of the device and the steady-state nonequilibrium density matrix, where the latter is expressed in terms of the nonequilibrium Green's functions and split into three contributions. Tracing these contributions with the torque operator automatically yields field-like and damping-like components of spin-transfer torque or spin-orbit torque vector, which is particularly advantageous for spin-orbit torque where the direction of these components depends on the unknown-in-advance orientation of the current-driven nonequilibrium spin density in the presence of spin-orbit coupling. We provide illustrative examples by computing spin-transfer torque in a one-dimensional toy model of a magnetic tunnel junction and realistic Co/Cu/Co spin-valve, both of which are described by first-principles Hamiltonians obtained from noncollinear density functional theory calculations; as well as spin-orbit torque in a ferromagnetic layer described by a tight-binding Hamiltonian which includes spin-orbit proximity effect within ferromagnetic monolayers assumed to be generated by the adjacent monolayer transition metal dichalcogenide.Comment: 22 pages, 9 figures, PDFLaTeX; prepared for Springer Handbook of Materials Modeling, Volume 2 Applications: Current and Emerging Material

P. falciparum In Vitro Killing Rates Allow to Discriminate between Different Antimalarial Mode-of-Action

Chemotherapy is still the cornerstone for malaria control. Developing drugs against Plasmodium parasites and monitoring their efficacy requires methods to accurately determine the parasite killing rate in response to treatment. Commonly used techniques essentially measure metabolic activity as a proxy for parasite viability. However, these approaches are susceptible to artefacts, as viability and metabolism are two parameters that are coupled during the parasite life cycle but can be differentially affected in response to drug actions. Moreover, traditional techniques do not allow to measure the speed-of-action of compounds on parasite viability, which is an essential efficacy determinant. We present here a comprehensive methodology to measure in vitro the direct effect of antimalarial compounds over the parasite viability, which is based on limiting serial dilution of treated parasites and re-growth monitoring. This methodology allows to precisely determine the killing rate of antimalarial compounds, which can be quantified by the parasite reduction ratio and parasite clearance time, which are key mode-of-action parameters. Importantly, we demonstrate that this technique readily permits to determine compound killing activities that might be otherwise missed by traditional, metabolism-based techniques. The analysis of a large set of antimalarial drugs reveals that this viability-based assay allows to discriminate compounds based on their antimalarial mode-of-action. This approach has been adapted to perform medium throughput screening, facilitating the identification of fast-acting antimalarial compounds, which are crucially needed for the control and possibly the eradication of malaria

The relationship between reported fever and Plasmodium falciparum infection in African children

<p>Abstract</p> <p>Background</p> <p>Fever has traditionally served as the entry point for presumptive treatment of malaria in African children. However, recent changes in the epidemiology of malaria across many places in Africa would suggest that the predictive accuracy of a fever history as a marker of disease has changed prompting calls for the change to diagnosis-based treatment strategies.</p> <p>Methods</p> <p>Using data from six national malaria indicator surveys undertaken between 2007 and 2009, the relationship between childhood (6-59 months) reported fever on the day of survey and the likelihood of coincidental <it>Plasmodium falciparum </it>infection recorded using a rapid diagnostic test was evaluated across a range of endemicities characteristic of Africa today.</p> <p>Results</p> <p>Of 16,903 children surveyed, 3% were febrile and infected, 9% were febrile without infection, 12% were infected but were not febrile and 76% were uninfected and not febrile. Children with fever on the day of the survey had a 1.98 times greater chance of being infected with <it>P. falciparum </it>compared to children without a history of fever on the day of the survey after adjusting for age and location (OR 1.98; 95% CI 1.74-2.34). There was a strong linear relationship between the percentage of febrile children with infection and infection prevalence (R²= 0.9147). The prevalence of infection in reported fevers was consistently greater than would be expected solely by chance and this increased with increasing transmission intensity. The data suggest that in areas where community-based infection prevalence in childhood is above 34-37%, 50% or more of fevers are likely to be associated with infection.</p> <p>Conclusion</p> <p>The potential benefits of diagnosis will depend on the prevalence of infection among children who report fever. The study has demonstrated a predictable relationship between parasite prevalence in the community and risks of infection among febrile children suggesting that current maps of parasite prevalence could be used to guide diagnostic strategies in Africa.</p

Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants

Background: Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories.Methods: We used data from 1990 to 2019 on people aged 30-79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age.Findings: The number of people aged 30-79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306-359) million women and 317 (292-344) million men in 1990 to 626 (584-668) million women and 652 (604-698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55-62) of women and 49% (46-52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43-51) of women and 38% (35-41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20-27) for women and 18% (16-21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran.Interpretation: Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings.Copyright (C) 2021 World Health Organization; licensee Elsevier.</p