525 research outputs found

    Effects of piperaquine, chloroquine, and amodiaquine on drug uptake and of these in combination with dihydroartemisinin against drug-sensitive and -resistant Plasmodium falciparum strains.

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    Piperaquine is being developed as a long-acting component in artemisinin combination therapies. It was highly active in vitro and drug interaction studies showed that dihydroartemisinin combinations with piperaquine, chloroquine, and amodiaquine were indifferent tending toward antagonism. Competitive uptake of radiolabeled chloroquine and dihydroartemisinin in combination with other antimalarials was observed

    Mutations in dhfr in Plasmodium falciparum infections selected by chlorproguanil-dapsone treatment.

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    Treatment with the novel antifolate drug combination chlorproguanil-dapsone effectively cleared asymptomatic Plasmodium falciparum infections in 246 (93.5%) of 263 children in the Usambara Mountains of Tanzania during the course of a 2-week follow-up. Samples from 71 recurrent infections, collected over a 9-week follow-up, showed selection for parasites with the triple mutant Ile(51)-Arg(59)-Asn(108) in dihydrofolate reductase. There was no selection for mutations in dihydropteroate synthetase, the target enzyme of dapsone. Search for complete identity in the highly polymorphic genes coding for merozoite surface proteins 1 and 2 in parasite samples collected before and after treatment indicated that the majority of recurrent parasitemias were new infections. These observations on selection in Tanzania and the lack of selection reported from a less endemic area suggest that the active metabolite of chlorproguanil, which has a short half-life in the blood, may persist in the liver, where it exerts selective pressure on growing preerythrocytic stages

    Labour supply and skills demands in fashion retailing

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    If, as Adam Smith once famously suggested, Britain was a nation of shopkeepers then it is now a nation of shopworkers. Retail is now a significant part of the UK economy, accounting for ÂŁ256 billion in sales and one-third of all consumer spending (Skillsmart, 2007). It is the largest private sector employer in the UK, employing 3m workers, or 1 in 10 of the working population. For future job creation in the UK economy retail is also similarly prominent and the sector is expected to create a further 250,000 jobs to 2014 (Skillsmart, 2007). The centrality of retail to economic success and job creation is apparent in other advanced economies. For example, within the US, retail sales is the occupation with the largest projected job growth in the period 2004-2014 (Gatta et al., 2009) and in Australia retail accounts for 1 in 6 workers (Buchanan et al., 2003). Within the UK these workers are employed in approximately 290,000 businesses, encompassing large and small organizations and also a number of sub-sectors. This variance suggests that retail should not be regarded as homogenous in its labour demands. Hart et al. (2007) note how skill requirements and the types of workers employed may differ across the sector. This chapter further opens up this point, providing an analysis of the labour supply and skills demands for the sub-sectors of clothing, footwear and leather goods, which are described by Skillsmart (2007: 48) as being 'significant categories in UK retailing'

    Influence of LAR and VAR on Para-Aminopyridine Antimalarials Targetting Haematin in Chloroquine-Resistance

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    Antimalarial chloroquine (CQ) prevents haematin detoxication when CQ-base concentrates in the acidic digestive vacuole through protonation of its p-aminopyridine (pAP) basic aro- matic nitrogen and sidechain diethyl-N. CQ export through the variant vacuolar membrane export channel, PFCRT, causes CQ-resistance in Plasmodium falciparum but 3-methyl CQ (sontochin SC), des-ethyl amodiaquine (DAQ) and bis 4-aminoquinoline piperaquine (PQ) are still active. This is determined by changes in drug accumulation ratios in parasite lipid (LAR) and in vacuolar water (VAR). Higher LAR may facilitate drug binding to and blocking PFCRT and also aid haematin in lipid to bind drug. LAR for CQ is only 8.3; VAR is 143,482. More hydrophobic SC has LAR 143; VAR remains 68,523. Similarly DAQ with a phenol sub- stituent has LAR of 40.8, with VAR 89,366. In PQ, basicity of each pAP is reduced by distal piperazine N, allowing very high LAR of 973,492, retaining VAR of 104,378. In another bis quinoline, dichlorquinazine (DCQ), also active but clinically unsatisfactory, each pAP retains basicity, being insulated by a 2-carbon chain from a proximal nitrogen of the single linking piperazine. While LAR of 15,488 is still high, the lowest estimate of VAR approaches 4.9 million. DCQ may be expected to be very highly lysosomotropic and therefore potentially hepatotoxic. In 11 pAP antimalarials a quadratic relationship between logLAR and logRe- sistance Index (RI) was confirmed, while log (LAR/VAR) vs logRI for 12 was linear. Both might be used to predict the utility of structural modifications

    The relationship of physico-chemical properties and structure to the differential antiplasmodial activity of the cinchona alkaloids

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    BACKGROUND: The 8-amino and 9-hydroxy substituents of antimalarial cinchona alkaloids have the erythro orientation while their inactive 9-epimers are threo. From the X-ray structures a 90° difference in torsion angle between the N1-H1 and C9-O12 bonds in the two series is believed to be important. In order to kill the malaria parasite, alkaloids must cross the erythrocyte and parasite membranes to accumulate in the acid digestive vacuole where they prevent detoxication of haematin produced during haemoglobin breakdown. METHODS: Ionization constants, octanol/water distribution and haematin interaction are examined for eight alkaloids to explain the influence of small structural differences on activity. RESULTS: Erythro isomers have a high distribution ratio of 55:1 from plasma to the erythrocyte membrane, while for the more basic threo epimers this is only 4.5:1. This gives an increased transfer rate of the erythro drugs into the erythrocyte and thence into the parasite vacuole where their favourable conformation allows interaction with haematin, inhibiting its dimerization strongly (90 ± 7%) and thereby killing the parasite. The threo compounds not only enter more slowly but are then severely restricted from binding to haematin by the gauche alignment of their N1-H1 and C9-O12 bonds. Confirmatory molecular models allowed measurement of angles and bond lengths and computation of the electronic spectrum of a quinine-haematin complex. CONCLUSION: Differences in the antiplasmodial activity of the erythro and threo cinchona alkaloids may therefore be attributed to the cumulative effects of lipid/aqueous distribution ratio and drug-haematin interaction. Possible insights into the mechanism of chloroquine-resistance are discussed

    Malarone treatment failure and in vitro confirmation of resistance of Plasmodium falciparum isolate from Lagos, Nigeria

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    We report the first in vitro and genetic confirmation of Malarone(Âź) (GlaxoSmithKline; atovaquone and proguanil hydrochloride) resistance in Plasmodium falciparum acquired in Africa. On presenting with malaria two weeks after returning from a 4-week visit to Lagos, Nigeria without prophylaxis, a male patient was given a standard 3-day treatment course of Malarone(Âź). Twenty-eight days later the parasitaemia recrudesced. Parasites were cultured from the blood and the isolate (NGATV01) was shown to be resistant to atovaquone and the antifolate pyrimethamine. The cytochrome b gene of isolate NGATV01 showed a single mutation, Tyr268Asn which has not been seen previously

    Workplace innovation : Europe's competitive edge : a manifesto for enhanced performance and working lives

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    Why a manifesto? Workplace innovation is an increasingly influential global movement. With strong European origins, it is increasingly recognised by policymakers and other stakeholders in countries across the world as a powerful tool in helping to achieve diverse economic and social policy goals, from inclusive growth and productivity to mental health and wellbeing in the workplace. For enterprise leaders, managers and employee representatives, it provides an actionable framework for effective, sustainable and win-win organisational change, one solidly grounded in research evidence as well as practical experience. Yet we know from successive EU-wide surveys (most recently the 2019 European Company Survey) that there is a long tail between the less than 20% of European companies using workplace innovation practices systematically throughout their organisations and the majority. The EU misses out on potential gains in business performance, workforce skills and health. Several European governments have recognised the importance of workplace innovation within their economic policy platforms and actively implement measures to enhance awareness, promote dissemination and stimulate research. The European Commission itself adopted workplace innovation as part of its policy portfolio, creating the European Workplace Innovation Network (EUWIN) in 2013. Since 2013, EUWIN has been a consistent advocate for the broader adoption of workplace innovation policies and programmes at regional, national and EU levels. Now supported solely by its partners in ten European countries, EUWIN welcomes the European Commission's continuing recognition of workplace innovation but argues strongly for expanding related measures in its industry, employment and research policy fields. EUWIN also argues for the expansion of national and regional policy measures throughout Europe, and enhancing awareness amongst social partners and other stakeholder bodies. This manifesto addresses the European Social Pillar agenda as well as the broader policy priorities of DG EMPL and DG GROW. It summarises the nature, origins and policy significance of workplace innovation, making a case for enhanced recognition throughout Europe's policy eco-system

    Objective Structured Professional Assessments for Trainee Educational Psychologists: an Evaluation

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    Objective Structured Professional Assessments (OSPAs) were developed and evaluated at three universities in the United Kingdom, to supplement supervisor assessments of trainee educational psychologists’ placement practice. Participating second year students on three educational psychology doctoral programmes (n = 31) and tutors (n = 12) were surveyed. Scenarios, developed with experienced practitioners, were considered authentic and relevant. Tutor feedback indicated that the marking scheme was a good basis for judgements, but required further calibration and standardisation. Strengths and limitations relating to authenticity of scenarios and practical arrangements were identified. Students considered OSPAs to be a valid assessment of communication and perspective-taking skills, although some found them to be anxiety provoking. Levels of authenticity and complexity were deemed appropriate, although there were concerns over time allowed and how the assessment criteria were interpreted. The discussion highlights how OSPAs address issues relating to assessment reliability by improving objectivity, reducing bias and providing uniformity to student assessment experiences

    Giving Miss Marple a makeover : graduate recruitment, systems failure and the Scottish voluntary sector

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    The voluntary sector in Scotland, as across the globe, is becoming increasingly business like. Resultantly, there is an increasing demand for graduates to work in business and support functions. In Scotland, however, despite an oversupply of graduates in the labor market, the voluntary sector reports skills shortages for graduate-level positions; a leadership deficit was also reported in countries such as the United States. Through exploratory, mainly qualitative, case study and stakeholder research, this article proposes that one reason for this mismatch between the supply of and demand for graduates is a systems failure within the sector. Many graduates and university students remain unaware of potentially suitable paid job opportunities, in part because of the sector's voluntary label. To rectify this systems failure, thought needs to be given to the sector's nomenclature and the manner in which voluntary sector organizations attract graduate recruits, for example, through levering value congruence in potential recruits
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