111 research outputs found

    Impact of annual praziquantel treatment on urogenital schistosomiasis in a seasonal transmission focus in central Senegal

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    In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a considerable impact on the transmission dynamics of S. haematobium in Niakhar, due to the nature of the epidemiological system with seasonal transmission. Thus, to maintain this benefit and continue to reduce the morbidity of urogenital schistosomiasis, other approaches should be integrated into the strategy plans of the National program to achieve the goal of urogenital schistosomiasis elimination in seasonal foci in Senegal

    The P2Y2 nucleotide receptor is an inhibitor of vascular calcification

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    BACKGROUND AND AIMS: Mutations in the 5'-nucleotidase ecto (NT5E) gene that encodes CD73, a nucleotidase that converts AMP to adenosine, are linked to arterial calcification. However, the role of purinergic receptor signaling in the pathology of intimal calcification is not well understood. In this study, we examined whether extracellular nucleotides acting via P2Y2 receptor (P2Y2R) modulate arterial intimal calcification, a condition highly correlated with cardiovascular morbidity. METHODS: Apolipoprotein E, P2Y2R double knockout mice (ApoE-/-P2Y2R-/-) were used to determine the effect of P2Y2R deficiency on vascular calcification in vivo. Vascular smooth muscle cells (VSMC) isolated from P2Y2R-/- mice grown in high phosphate medium were used to assess the role of P2Y2R in the conversion of VSMC into osteoblasts. Luciferase-reporter assays were used to assess the effect of P2Y2R on the transcriptional activity of Runx2. RESULTS: P2Y2R deficiency in ApoE-/- mice caused extensive intimal calcification despite a significant reduction in atherosclerosis and macrophage plaque content. The ectoenzyme apyrase that degrades nucleoside di- and triphosphates accelerated high phosphate-induced calcium deposition in cultured VSMC. Expression of P2Y2R inhibits calcification in vitro inhibited the osteoblastic trans-differentiation of VSMC. Mechanistically, expression of P2Y2R inhibited Runx2 transcriptional activation of an osteocalcin promoter driven luciferase reporter gene. CONCLUSIONS: This study reveals a role for vascular P2Y2R as an inhibitor of arterial intimal calcification and provides a new mechanistic insight into the regulation of the osteoblastic trans-differentiation of SMC through P2Y2R-mediated Runx2 antagonism. Given that calcification of atherosclerotic lesions is a significant clinical problem, activating P2Y2R may be an effective therapeutic approach for treatment or prevention of vascular calcification

    Innovation Adoption in Robotic Surgery - A Surgical Innovation Framework using Royal Bournemouth Hospital

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    Robotic Surgery is studied as an innovative surgical procedure and we examine the way Robotic Surgery is adopted by healthcare professionals in Royal Bournemouth Hospital. This research aims to develop a Surgical Innovation Framework (SIF) that incorporates the broader adoption of surgical innovation for the National Health Service (NHS) in the United Kingdom. The aim of the framework is to assist the NHS in its determination and adoption of surgical innovation. The framework is developed taking into consideration The recent reports by the Department of Health and Social Care, NHS, NICE and existing body of knowledge. The proposed model considers unique characteristics of Robotic Surgery, NHS as the host organization, healthcare professionals as adopters and other elements such as communication channels. An end-to-end communication pathway is developed for the robotic surgery team to identify stakeholders involved in this process

    Mitochondrial diversity analysis of Glossina palpalis gambiensis from Mali and Senegal

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    West African riverine tsetse populations of Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) were investigated for gene flow, inferred from mitochondrial diversity in samples of 69 flies from Senegal and 303 flies from three river drainages in Mali. Four polymorphic mitochondrial loci were scored. Mean haplotype diversities were 0.30 in Mali and 0.18 over both Mali and Senegal. These diversities estimate the probabilities that two randomly chosen tsetse have different haplotypes. Substantial rates of gene flow were detected among flies sampled along tributaries belonging to the river basins of the Senegal, Niger, and Bani in Mali. There was virtually no gene flow between tsetse in Senegal and Mali. No seasonal effects on gene flow were detected. The implications of these preliminary findings for the implementation of area-wide integrated pest management (AW-IPM) programmes against riverine tsetse in West Africa are discussed

    Extracellular ATP is a pro-angiogenic factor for pulmonary artery vasa vasorum endothelial cells

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    Expansion of the vasa vasorum network has been observed in a variety of systemic and pulmonary vascular diseases. We recently reported that a marked expansion of the vasa vasorum network occurs in the pulmonary artery adventitia of chronically hypoxic calves. Since hypoxia has been shown to stimulate ATP release from both vascular resident as well as circulatory blood cells, these studies were undertaken to determine if extracellular ATP exerts angiogenic effects on isolated vasa vasorum endothelial cells (VVEC) and/or if it augments the effects of other angiogenic factors (VEGF and basic FGF) known to be present in the hypoxic microenvironment. We found that extracellular ATP dramatically increases DNA synthesis, migration, and rearrangement into tube-like networks on Matrigel in VVEC, but not in pulmonary artery (MPAEC) or aortic (AOEC) endothelial cells obtained from the same animals. Extracellular ATP potentiated the effects of both VEGF and bFGF to stimulate DNA synthesis in VVEC but not in MPAEC and AOEC. Analysis of purine and pyrimidine nucleotides revealed that ATP, ADP and MeSADP were the most potent in stimulating mitogenic responses in VVEC, indicating the involvement of the family of P2Y1-like purinergic receptors. Using pharmacological inhibitors, Western blot analysis, and Phosphatidylinositol-3 kinase (PI3K) in vitro kinase assays, we found that PI3K/Akt/mTOR and ERK1/2 play a critical role in mediating the extracellular ATP-induced mitogenic and migratory responses in VVEC. However, PI3K/Akt and mTOR/p70S6K do not significantly contribute to extracellular ATP-induced tube formation on Matrigel. Our studies indicate that VVEC, isolated from the sites of active angiogenesis, exhibit distinct functional responses to ATP, compared to endothelial cells derived from large pulmonary or systemic vessels. Collectively, our data support the idea that extracellular ATP participates in the expansion of the vasa vasorum that can be observed in hypoxic conditions

    P2 receptors in atherosclerosis and postangioplasty restenosis

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    Atherosclerosis is an immunoinflammatory process that involves complex interactions between the vessel wall and blood components and is thought to be initiated by endothelial dysfunction [Ross (Nature 362:801–09, 1993); Fuster et al. (N Engl J Med 326:242–50, 1992); Davies and Woolf (Br Heart J 69:S3–S11, 1993)]. Extracellular nucleotides that are released from a variety of arterial and blood cells [Di Virgilio and Solini (Br J Pharmacol 135:831–42, 2002)] can bind to P2 receptors and modulate proliferation and migration of smooth muscle cells (SMC), which are known to be involved in intimal hyperplasia that accompanies atherosclerosis and postangioplasty restenosis [Lafont et al. (Circ Res 76:996–002, 1995)]. In addition, P2 receptors mediate many other functions including platelet aggregation, leukocyte adherence, and arterial vasomotricity. A direct pathological role of P2 receptors is reinforced by recent evidence showing that upregulation and activation of P2Y2 receptors in rabbit arteries mediates intimal hyperplasia [Seye et al. (Circulation 106:2720–726, 2002)]. In addition, upregulation of functional P2Y receptors also has been demonstrated in the basilar artery of the rat double-hemorrhage model [Carpenter et al. (Stroke 32:516–22, 2001)] and in coronary artery of diabetic dyslipidemic pigs [Hill et al. (J Vasc Res 38:432–43, 2001)]. It has been proposed that upregulation of P2Y receptors may be a potential diagnostic indicator for the early stages of atherosclerosis [Elmaleh et al. (Proc Natl Acad Sci U S A 95:691–95, 1998)]. Therefore, particular effort must be made to understand the consequences of nucleotide release from cells in the cardiovascular system and the subsequent effects of P2 nucleotide receptor activation in blood vessels, which may reveal novel therapeutic strategies for atherosclerosis and restenosis after angioplasty

    Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death

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    The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201

    Pathogenicity of the Fungus, Aspergillus clavatus, Isolated from the Locust, Oedaleus senegalensis, Against Larvae of the Mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus

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    The use of insect pathogenic fungi is a promising alternative to chemical control against mosquitoes. Among the Hyphomycetes isolated from insects for mosquito control, the genus Aspergillus remains the least studied. In September 2005, four fungi were isolated from the Senegalese locust, Oedaleus senegalensis Kraus (Orthoptera: Acrididae), collected in Dakar, Senegal. One of these fungi, identified as Aspergillus clavatus, Desmazières (Eurotiales: Trichocomaceae) was highly pathogenic against larvae of the mosquitoes Aedes aegypti L., Anopheles gambiae s.l. Giles and Culex quinquefasciatus Say (Diptera: Culicidae). An application of 1.2 mg/ml dry conidia yielded 100% mortality after 24 hours against both Ae. aegypti and Cx. quinquefasciatus while with An. gambiae it was 95%. With unidentified species in the genus Aspergillus, mortality after 24 h was <5% against all the larval species. Application of A. clavatus produced in a wheat powder medium using doses ranging between 4.3 to 21×107 spores/ml, caused 11 to 68% mortality against Cx. quinquefasciatus at 24h, and 37 to 100% against Ae. aegypti. Microscopic observations showed fungal germination on both Ae. aegypti and Cx. quinquefasciatus larvae. Histological studies revealed that A. clavatus penetrated the cuticle, invaded the gut and disintegrated its cells. Some Cx. quinquefasciatus larvae, treated with A. clavatus reached the pupal stage and produced infected adults. However, the infection was mainly located on the extremity of their abdomen. These results suggest that A. clavatus could be an effective tool to manage mosquito proliferation

    P2X7 nucleotide receptors mediate caspase-8/9/3-dependent apoptosis in rat primary cortical neurons

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    Apoptosis is a major cause of cell death in the nervous system. It plays a role in embryonic and early postnatal brain development and contributes to the pathology of neurodegenerative diseases. Here, we report that activation of the P2X7 nucleotide receptor (P2X7R) in rat primary cortical neurons (rPCNs) causes biochemical (i.e., caspase activation) and morphological (i.e., nuclear condensation and DNA fragmentation) changes characteristic of apoptotic cell death. Caspase-3 activation and DNA fragmentation in rPCNs induced by the P2X7R agonist BzATP were inhibited by the P2X7R antagonist oxidized ATP (oATP) or by pre-treatment of cells with P2X7R antisense oligonucleotide indicating a direct involvement of the P2X7R in nucleotide-induced neuronal cell death. Moreover, Z-DEVD-FMK, a specific and irreversible cell permeable inhibitor of caspase-3, prevented BzATP-induced apoptosis in rPCNs. In addition, a specific caspase-8 inhibitor, Ac-IETD-CHO, significantly attenuated BzATP-induced caspase-9 and caspase-3 activation, suggesting that P2X7R-mediated apoptosis in rPCNs occurs primarily through an intrinsic caspase-8/9/3 activation pathway. BzATP also induced the activation of C-jun N-terminal kinase 1 (JNK1) and extracellular signal-regulated kinases (ERK1/2) in rPCNs, and pharmacological inhibition of either JNK1 or ERK1/2 significantly reduced caspase activation by BzATP. Taken together, these data indicate that extracellular nucleotides mediate neuronal apoptosis through activation of P2X7Rs and their downstream signaling pathways involving JNK1, ERK and caspases 8/9/3
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