Invasion of Africa by a single pfcrt allele of South East Asian type

BACKGROUND: Because of its dramatic public health impact, Plasmodium falciparum resistance to chloroquine (CQ) has been documented early on. Chloroquine-resistance (CQR) emerged in the late 1950's independently in South East Asia and South America and progressively spread over all malaria areas. CQR was reported in East Africa in the 1970's, and has since invaded the African continent. Many questions remain about the actual selection and spreading process of CQR parasites, and about the evolution of the ancestral mutant gene(s) during spreading. METHODS: Eleven clinical isolates of P. falciparum from Cambodia and 238 from Africa (Senegal, Ivory Coast, Bukina Faso, Mali, Guinea, Togo, Benin, Niger, Congo, Madagascar, Comoros Islands, Tanzania, Kenya, Mozambique, Cameroun, Gabon) were collected during active case detection surveys carried out between 1996 and 2001. Parasite DNA was extracted from frozen blood aliquots and amplification of the gene pfcrt exon 2 (codon 72–76), exon 4 and intron 4 (codon 220 and microsatellite marker) were performed. All fragments were sequenced. RESULTS: 124 isolates with a sensitive (c76/c220:CVMNK/A) haplotype and 125 isolates with a resistant c76/c220:CVIET/S haplotype were found. The microsatellite showed 17 different types in the isolates carrying the c76/c220:CVMNK/A haplotype while all 125 isolates with a CVIET/S haplotype but two had a single microsatellite type, namely (TAAA)3(TA)15, whatever the location or time of collection. CONCLUSION: Those results are consistent with the migration of a single ancestral pfcrt CQR allele from Asia to Africa. This is related to the importance of PFCRT in the fitness of P. falciparum point out this protein as a potential target for developments of new antimalarial drugs

Sécurité virale des greffons osseux (application à la validation de dossiers réglementaires à l'AFSSAPS)

PARIS-BIUP (751062107) / SudocSudocFranceF

L'empereur / Jacques Duchemin

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A multiparametric approach for monitoring immunotoxic responses in mussels from contaminated sites in Western Mediterranea

International audienceAs a part of the multidisciplinary program Biological Effects of Environmental Pollution in Marine Coastal Ecosystems of the European Commission, this study aimed to validate immunological alterations as biomarkers of exposure to chemical contamination in polluted areas of Western Mediterranea. The status of the immune system has been assessed in mussels (Mytilus galloprovincialis) by measuring several immunopathological and immunocompetence parameters. Alterations of total hemocyte counts, lysosomal stability, and phagocytosis were among the most reliable effects observed in polluted sites and suggested immunosuppressive conditions in contaminated mussels. An immunotoxicological index was calculated from the set of individual data. By providing a single value per sampling station to score immunological alterations in mussels, this novel approach allowed recognition of a gradient of perturbation correlated to pollution intensity in two of the three sites monitored. Processing a set of biological parameters by this method was found to increase the ecotoxicological relevance of such multiparametric studies for the assessement of chemical contamination in coastal waters

Notre guerre au Katanga

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Meta-analysis of the parasitic phase traits of Haemonchus contortus infection in sheep

International audienceBackground: The parasitic nematode Haemonchus contortus shows highly variable life history traits. This highlights the need to have an average estimate and a quantification of the variation around it to calibrate epidemiological models.Methods: This paper aimed to quantify the main life history traits of H. contortus and to identify explanatory factors affecting these traits using a powerful method based on a systematic review and meta-analysis of current literature. The life history traits considered are: (i) the establishment rate of ingested larvae; (ii) the adult mortality rate; (iii) the fertility (i. e. the number of eggs laid/ female/ day); and (iv) fecundity of female worms (i. e. the number of eggs per gram of faeces).Results: A total of 37 papers that report single experimental infection with H. contortus in sheep and published from 1960 to 2015, were reviewed and collated in this meta-analysis. This encompassed 115 experiments on 982 animals. Each trait was analysed using a linear model weighted by its inverse variance. The average (+/- SE) larval establishment rate was 0.24 +/- 0.02, which decreased as a function of the infection dose and host age. An average adult mortality rate of 0.021 +/- 0.002) was estimated from the literature. This trait varied as a function of animal age, breed and protective response due to prior exposure to the parasite. Average female fertility was 1295.9 +/- 280.4 eggs/female/day and decreased in resistant breeds and previously infected hosts. Average faecal egg count at necropsy was 908.5 +/- 487.1 eggs per gram of faeces and varied as a function of infection duration and host resistance. The average sex ratio of H. contortus was 0.51 +/- 0.006.Conclusion: This work is the first systematic review to summarise the available information on the parasitic phase of H. contortus in sheep. The results of the meta-analysis provide robust estimates of life history traits for parametrization of epidemiological models, their expected variation according to experimental factors, and provides correlations between these

Revealing the spectral response of a plasmonic structure using tunnel electrons

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Computerized CHA2DS2Vasc classification in remote atrial fibrillation alerts: an ontology-based approach

International audienceIntroduction: Atrial fibrillation (AF) notifications in remote monitoring represent a high medical burden in terms of alert management. In the AKENATON project (Automated Knowledge Extraction from medical records iN Association with a Telecardiolgy Observation Network), we developed a method based on the integration of clinical information with data transmitted by implantable cardiac devices for clinical decision support purposes.Methods: Patient (pt) data were extracted from available textual or structured documents by an information extraction tool, and integrated with data extracted from device memories into a specific data model. An ontology (knowledge model) offering reasoning capabilities based on this data model was used to classify AF alerts. The thrombo-embolic risk (Low (L)/Medium (M)/High (H)/Critical (C)) based on CHA2DS2VASc score, medication and AF episode duration (Figure 1) was estimated by the system for 60 pts and compared to manual review by a domain expert. Results: At the level of the CHA2DS2VASc calculation (8 criteria per pt), 446 out of the 480 criteria to be estimated by the system were correct, resulting in 58 (97\%) pts with correct CHA2DS2VASc score classification (0/1/2+). Medication was adequately evaluated in 57 (95\%) pts. The final alert classification (11 L, 13 M, 31 H and 5 C) was correct for all pts minus one case of risk over-estimation (C instead of H).Conclusion: This work proves the ability of the system to better classify alerts and improve alert response based on clinical data. Such method could be of great use for remote monitoring and extended to other use cases and domains

Revealing the spectral response of a plasmonic lens using low-energy electrons

International audiencePlasmonic lenses, even of simple design, may have intricate spectral behavior. The spectral response of a plasmonic lens to a local, broadband excitation has rarely been studied despite its central importance in future applications. Here we use the unique combination of scanning tunneling microscopy (STM) and angle-resolved optical spectroscopy to probe the spectral response of a plasmonic lens. Such a lens consists of a series of concentric circular slits etched in a thick gold film. Spectrally broad, circular surface plasmon polariton (SPP) waves are electrically launched from the STM tip at the plasmonic lens center, and these waves scatter at the slits into a narrow, out-of-plane, light beam. We show that the angular distribution of the emitted light results from the interplay of the size of the plasmonic lens and the spectral width of the SPP nanosource. We then propose simple design rules for optimized light beaming with the smallest possible footprint. The spectral distribution of the emitted light depends not only on the SPP nanosource, but on the local density of electromagnetic states (EM-LDOS) at the nanosource position, which in turn depends on the cavity modes of the plasmonic microstructure. The key parameters for tailoring the spectral response of the plasmonic lens are the period of the slits forming the lens, the number of slits, and the lens inner diameter