Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, enlarge the parasite's food vacuole and alter drug sensitivities

Mutations in the Plasmodium falciparum chloroquine resistance transporter, PfCRT, are the major determinant of chloroquine resistance in this lethal human malaria parasite. Here, we describe P. falciparum lines subjected to selection by amantadine or blasticidin that carry PfCRT mutations (C101F or L272F), causing the development of enlarged food vacuoles. These parasites also have increased sensitivity to chloroquine and some other quinoline antimalarials, but exhibit no or minimal change in sensitivity to artemisinins, when compared with parental strains. A transgenic parasite line expressing the L272F variant of PfCRT confirmed this increased chloroquine sensitivity and enlarged food vacuole phenotype. Furthermore, the introduction of the C101F or L272F mutation into a chloroquine-resistant variant of PfCRT reduced the ability of this protein to transport chloroquine by approximately 93 and 82%, respectively, when expressed in Xenopus oocytes. These data provide, at least in part, a mechanistic explanation for the increased sensitivity of the mutant parasite lines to chloroquine. Taken together, these findings provide new insights into PfCRT function and PfCRT-mediated drug resistance, as well as the food vacuole, which is an important target of many antimalarial drugs

Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands

Carbon stable isotope (δ¹³C) records from vascular plant dominated peatlands have been used as a palaeoclimate proxy, but a better empirical understanding of fractionation processes in these ecosystems is required. Here, we test the potential of δ¹³C analysis of ombrotrophic restiad peatlands in New Zealand, dominated by the wire rush (Empodisma spp.), to provide a methodology for developing palaeoclimatic records. We took surface plant samples alongside measurements of water table depth and (micro)climate over spatial (six sites spanning > 10 latitude) and temporal (monthly measurements over 1 year) gradients and analysed the relationships between cellulose δ¹³C values and environmental parameters. We found strong, significant negative correlations between δ¹³C and temperature, photosynthetically active radiation and growing degree days above 0 C. No significant relationships were observed between δ¹³C and precipitation, relative humidity, soil moisture or water table depth, suggesting no growing season water limitation and a decoupling of the expected link between δ¹³C in vascular plants and hydrological variables. δ¹³C of Empodisma spp. roots may therefore provide a valuable temperature proxy in a climatically sensitive region, but further physiological and sub-fossil calibration studies are required to fully understand the observed signal

Crowdsourcing the General Public for Large Scale Molecular Pathology Studies in Cancer

Background: Citizen science, scientific research conducted by non-specialists, has the potential to facilitate biomedical research using available large-scale data, however validating the results is challenging. The Cell Slider is a citizen science project that intends to share images from tumors with the general public, enabling them to score tumor markers independently through an internet-based interface. Methods: From October 2012 to June 2014, 98,293 Citizen Scientists accessed the Cell Slider web page and scored 180,172 sub-images derived from images of 12,326 tissue microarray cores labeled for estrogen receptor (ER). We evaluated the accuracy of Citizen Scientist's ER classification, and the association between ER status and prognosis by comparing their test performance against trained pathologists. Findings: The area under ROC curve was 0.95 (95% CI 0.94 to 0.96) for cancer cell identification and 0.97 (95% CI 0.96 to 0.97) for ER status. ER positive tumors scored by Citizen Scientists were associated with survival in a similar way to that scored by trained pathologists. Survival probability at 15 years were 0.78 (95% CI 0.76 to 0.80) for ER-positive and 0.72 (95% CI 0.68 to 0.77) for ER-negative tumors based on Citizen Scientists classification. Based on pathologist classification, survival probability was 0.79 (95% CI 0.77 to 0.81) for ER-positive and 0.71 (95% CI 0.67 to 0.74) for ER-negative tumors. The hazard ratio for death was 0.26 (95% CI 0.18 to 0.37) at diagnosis and became greater than one after 6.5 years of follow-up for ER scored by Citizen Scientists, and 0.24 (95% CI 0.18 to 0.33) at diagnosis increasing thereafter to one after 6.7 (95% CI 4.1 to 10.9) years of follow-up for ER scored by pathologists. Interpretation: Crowdsourcing of the general public to classify cancer pathology data for research is viable, engages the public and provides accurate ER data. Crowdsourced classification of research data may offer a valid solution to problems of throughput requiring human input

Views of the public about Snacktivity™: a small changes approach to promoting physical activity and reducing sedentary behaviour

Background: Many people do not meet the recommended health guidance of participation in a minimum of 150–300 min of moderate intensity physical activity per week, often promoted as at least 30 min of physical activity on 5 days of the week. This is concerning and highlights the importance of finding innovative ways to help people to be physically active each day. Snacktivity™ is a novel approach that aims to encourage people to do small, 2–5 min bouts of physical activity ‘snacks’ throughout the whole day, such that they achieve at least 150 min of moderate intensity activity per week. However, before it can be recommended, there is a need to explore whether the concept is acceptable to the public. Methods: A survey to assess the views of the public about Snacktivity™ was distributed to adult patients registered at six general practices in the West Midlands, UK and to health care employees in the same region. Results: A total of 5989 surveys were sent to patients, of which 558 were returned (9.3%). A further 166 surveys were completed by health care employees. A total of 85% of respondents liked the Snacktivity™ concept. The flexibility of the approach was highly rated. A high proportion of participants (61%) reported that the ability to self-monitor their behaviour would help them to do Snacktivity™ throughout their day. Physically inactive participants perceived that Snacktivity™ would help to increase their physical activity, more than those who were physically active (OR = 0.41, 95% CI: 0.25–0.67). Approximately 90% of respondents perceived that Snacktivity™ was easy to do on a non-working day compared to 60% on a working day. Aerobic activity ‘snacks’ were preferred to those which were strength based. Conclusions: The Snacktivity™ approach to promoting physical activity was viewed positively by the public and interventions to test the merits of such an approach now need to be developed and tested in a variety of everyday contexts

A Novel murine model identifies cooperating mutations and therapeutic targets critical for chronic myeloid leukemia progression

The introduction of highly selective ABL-tyrosine kinase inhibitors (TKIs) has revolutionized therapy for chronic myeloid leukemia (CML). However, TKIs are only efficacious in the chronic phase of the disease and effective therapies for TKI-refractory CML, or after progression to blast crisis (BC), are lacking. Whereas the chronic phase of CML is dependent on BCR-ABL, additional mutations are required for progression to BC. However, the identity of these mutations and the pathways they affect are poorly understood, hampering our ability to identify therapeutic targets and improve outcomes. Here, we describe a novel mouse model that allows identification of mechanisms of BC progression in an unbiased and tractable manner, using transposon-based insertional mutagenesis on the background of chronic phase CML. Our BC model is the first to faithfully recapitulate the phenotype, cellular and molecular biology of human CML progression. We report a heterogeneous and unique pattern of insertions identifying known and novel candidate genes and demonstrate that these pathways drive disease progression and provide potential targets for novel therapeutic strategies. Our model greatly informs the biology of CML progression and provides a potent resource for the development of candidate therapies to improve the dismal outcomes in this highly aggressive disease.Work in the Huntly laboratory is funded by CRUK, The European Research Council (ERC), Leukaemia Lymphoma Research, the Kay Kendall Leukaemia Fund, Wellcome Trust, the Medical Research Council (UK), the Leukemia Lymphoma Society America and the Cambridge NIHR Biomedical Research centre. David Adams is funded by Cancer Research UK and Wellcome Trust. Steffen Koschmieder has received funding from Deutsche José Carreras Leukämie-Stiftung (DJCLS; grant 10/23).This is the final published version. It first appeared at http://dx.doi.org/10.1084/jem.2014166

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Dental abnormalities associated with a chromosome 2 deletion.

This case report describes the dental and physical anomalies observed in a young female patient who had a chromosome abnormality involving deletion of the q 33-q 35 region of chromosome 2. The dental dysplasia observed in this patient is proposed to be of genetic origin but the complication of anoxia at birth makes it difficult to assign the intellectual and physical impairments solely to the genetic deletion

Time-marching on the slow manifold: The relationship between the nonlinear Galerkin method and implicit timestepping algorithms

Implicit timestepping schemes and the Nonlinear Galerkin (NG) algorithms are competitors for integrating on the slow manifold, that is, for computing solutions when the timestep- limiting high frequencies are physically unimportant and most of the energy is in low frequency flow. We show that implicit schemes are always at least as accurate as the lowest nontrivial NG method, and can be made superior to even high order NG schemes by shortening the time step.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31731/1/0000670.pd