1,095 research outputs found

    A genomic and evolutionary approach reveals non-genetic drug resistance in malaria

    Get PDF
    Background: Drug resistance remains a major public health challenge for malaria treatment and eradication. Individual loci associated with drug resistance to many antimalarials have been identified, but their epistasis with other resistance mechanisms has not yet been elucidated. Results: We previously described two mutations in the cytoplasmic prolyl-tRNA synthetase (cPRS) gene that confer resistance to halofuginone. We describe here the evolutionary trajectory of halofuginone resistance of two independent drug resistance selections in Plasmodium falciparum. Using this novel methodology, we discover an unexpected non-genetic drug resistance mechanism that P. falciparum utilizes before genetic modification of the cPRS. P. falciparum first upregulates its proline amino acid homeostasis in response to halofuginone pressure. We show that this non-genetic adaptation to halofuginone is not likely mediated by differential RNA expression and precedes mutation or amplification of the cPRS gene. By tracking the evolution of the two drug resistance selections with whole genome sequencing, we further demonstrate that the cPRS locus accounts for the majority of genetic adaptation to halofuginone in P. falciparum. We further validate that copy-number variations at the cPRS locus also contribute to halofuginone resistance. Conclusions: We provide a three-step model for multi-locus evolution of halofuginone drug resistance in P. falciparum. Informed by genomic approaches, our results provide the first comprehensive view of the evolutionary trajectory malaria parasites take to achieve drug resistance. Our understanding of the multiple genetic and non-genetic mechanisms of drug resistance informs how we will design and pair future anti-malarials for clinical use. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0511-2) contains supplementary material, which is available to authorized users

    The effectiveness of critical time intervention for abused women leaving women’s shelters: a randomized controlled trial

    Full text link
    Objectives: To examine the effectiveness of critical time intervention (CTI)—an evidence-based intervention—for abused women transitioning from women’s shelters to community living. Methods A randomized controlled trial was conducted in nine women’s shelters across the Netherlands. 136 women were assigned to CTI (n = 70) or care-as-usual (n = 66). Data were analyzed using intention-to-treat three-level mixed-effects models. Results: Women in the CTI group had significant fewer symptoms of post-traumatic stress (secondary outcome) (adjusted mean difference - 7.27, 95% CI - 14.31 to - 0.22) and a significant fourfold reduction in unmet care needs (intermediate outcome) (95% CI 0.06–0.94) compared to women in the care-as-usual group. No differences were found for quality of life (primary outcome), re-abuse, symptoms of depression, psychological distress, self-esteem (secondary outcomes), family support, and social support (intermediate outcomes). Conclusions: This study shows that CTI is effective in a population of abused women in terms of a reduction of posttraumatic stress symptoms and unmet care needs. Because follow-up ended after the prescribed intervention period, further research is needed to determine the full long-term effects of CTI in this population

    Laser-Induced Fluorescence Velocimetry of Xe

    No full text
    We present laser-induced fluorescence (LIF) measurements of Xe II ( 4 D 7/2 ) in the FMT-2 ion engine plume. Three 605.1 nm beams from a ring dye laser are focused through a single lens into a submillimeter interrogation volume, from which we collect LIF at 529.2 nm. Fourier-transform deconvolution of the LIF spectra returns ion velocity distribution estimates along the three laser beam directions. From this, we calculate axial, radial and vertical components of the mean ion velocity and temperature from 1 mm to 300 mm downstream of the accelerator grid. The error propagation endemic to this off-axis multiplex LIF technique obscures the location of the neutralization plane in axial profiles of axial velocity, while radial sweeps of axial and vertical velocity show no discernable trend. Radial profiles of radial velocity, however, show increasing divergence with radial position

    Socially sensitive lactation: Exploring the social context of breastfeeding

    Get PDF
    Many women report difficulties with breastfeeding and do not maintain the practice for as long as intended. Although psychologists and other researchers have explored some of the difficulties they experience, fuller exploration of the relational contexts in which breastfeeding takes place is warranted to enable more in-depth analysis of the challenges these pose for breastfeeding women. The present paper is based on qualitative data collected from 22 first-time breastfeeding mothers through two phases of interviews and audio-diaries which explored how the participants experienced their relationships with significant others and the wider social context of breastfeeding in the first five weeks postpartum. Using a thematic analysis informed by symbolic interactionism, we develop the overarching theme of ‘Practising socially sensitive lactation’ which captures how participants felt the need to manage tensions between breastfeeding and their perceptions of the needs, expectations and comfort of others. We argue that breastfeeding remains a problematic social act, despite its agreed importance for child health. Whilst acknowledging the limitations of our sample and analytic approach, we suggest ways in which perinatal and public health interventions can take more effective account of the social challenges of breastfeeding in order to facilitate the health and psychological well-being of mothers and their infants
    corecore