1,129 research outputs found

    The impact of cell crowding and active cell movement on vascular tumour growth

    Get PDF
    A multiscale model for vascular tumour growth is presented which includes systems of ordinary differential equations for the cell cycle and regulation of apoptosis in individual cells, coupled to partial differential equations for the spatio-temporal dynamics of nutrient and key signalling chemicals. Furthermore, these subcellular and tissue layers are incorporated into a cellular automaton framework for cancerous and normal tissue with an embedded vascular network. The model is the extension of previous work and includes novel features such as cell movement and contact inhibition. We presented a detailed simulation study of the effects of these additions on the invasive behaviour of tumour cells and the tumour's response to chemotherapy. In particular, we find that cell movement alone increases the rate of tumour growth and expansion, but that increasing the tumour cell carrying capacity leads to the formation of less invasive dense hypoxic tumours containing fewer tumour cells. However, when an increased carrying capacity is combined with significant tumour cell movement, the tumour grows and spreads more rapidly, accompanied by large spatio-temporal fluctuations in hypoxia, and hence in the number of quiescent cells. Since, in the model, hypoxic/quiescent cells produce VEGF which stimulates vascular adaptation, such fluctuations can dramatically affect drug delivery and the degree of success of chemotherapy

    The constancy of global regulation across a species: the concentrations of ppGpp and RpoS are strain-specific in Escherichia coli.

    Get PDF
    BACKGROUND: Sigma factors and the alarmone ppGpp control the allocation of RNA polymerase to promoters under stressful conditions. Both ppGpp and the sigma factor σS (RpoS) are potentially subject to variability across the species Escherichia coli. To find out the extent of strain variation we measured the level of RpoS and ppGpp using 31 E. coli strains from the ECOR collection and one reference K-12 strain. RESULTS: Nine ECORs had highly deleterious mutations in rpoS, 12 had RpoS protein up to 7-fold above that of the reference strain MG1655 and the remainder had comparable or lower levels. Strain variation was also evident in ppGpp accumulation under carbon starvation and spoT mutations were present in several low-ppGpp strains. Three relationships between RpoS and ppGpp levels were found: isolates with zero RpoS but various ppGpp levels, strains where RpoS levels were proportional to ppGpp and a third unexpected class in which RpoS was present but not proportional to ppGpp concentration. High-RpoS and high-ppGpp strains accumulated rpoS mutations under nutrient limitation, providing a source of polymorphisms. CONCLUSIONS: The ppGpp and σS variance means that the expression of genes involved in translation, stress and other traits affected by ppGpp and/or RpoS are likely to be strain-specific and suggest that influential components of regulatory networks are frequently reset by microevolution. Different strains of E. coli have different relationships between ppGpp and RpoS levels and only some exhibit a proportionality between increasing ppGpp and RpoS levels as demonstrated for E. coli K-12

    Long-term glycaemic control with metformin– sulphonylurea–pioglitazone triple therapy in PROactive (PROactive 17)

    Full text link
    peer reviewedAims We assessed the long-term glycaemic effects and the safety profile of triple therapy with the addition of pioglitazone vs. placebo in patients with Type 2 diabetes treated with combined metformin–sulphonylurea therapy in the PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive). Methods In a post-hoc analysis, we identified patients treated with metformin plus sulphonylurea combination therapy and not receiving insulin at baseline (n = 1314). In those patients, we compared the effects of pioglitazone (force-titrated to 45 mg⁄ day, n = 654) vs. placebo (n = 660) on glycated haemoglobin (HbA1c) reduction, concomitant changes in medications and initiation of permanent insulin use (defined as daily insulin use for a period of ‡ 90 days or ongoing use at death ⁄ final visit). Results Significantly greater reductions in HbA1c and greater proportions of patients with HbA1c at target were noted with pioglitazone vs, placebo, despite a decrease in the use of other oral glucose-lowering agents. Therewas an approximate twofold increase in progression to permanent insulin use in the placebo group vs. the pioglitazone group: 31.1 vs. 16.1%, respectively, when added to combination therapy. The overall safety of themetformin–sulphonylurea–pioglitazone triple therapy was good. Conclusions Intensifying an existing dual oral therapy regimen to a triple oral regimen by adding pioglitazone to the classical metformin–sulphonylurea combination resulted in sustained improvements in glycaemic control and reduced progression to insulin therapy. The advantages and disadvantages of adding pioglitazone instead of adding basal insulin should be assessed further

    Pain associated with pressure injury: A qualitative study of community-based, home-dwelling individuals

    Get PDF
    © 2017 John Wiley & Sons Ltd. Aims: The aim of this study was to provide deep insights into the pain associated with pressure injuries in home-dwelling individuals using narrative accounts. Background: Pressure injuries or pressure ulcers are burdensome and costly. Prevalence data, surveys and systematic reviews demonstrate that pain associated with pressure injury is widespread, but voices of home-dwelling patients have remained largely unheard. Design: Concurrent mixed methods case study of a UK community of approximately 50,000 adults. Methods: Qualitative interviews, conducted in 2016, of 12 home-dwelling adult participants with a current pressure injury (n = 10), or a recently healed pressure injury (n = 2). Findings: Pain had an adverse impact on activities of daily living, mobility and sleep. Participants described days that were clouded in pain; a pain they felt was poorly understood and often out of control. Thematic content analysis revealed two major themes; these are: Poorly controlled pain: “I just want the pain to go away”; and, Uncertainty for the future: “it almost seems insurmountable.”. Conclusion: Findings of our study support the need to develop an appropriate assessment tool for pressure injury patients in the community to enable healthcare professionals and patients to recognize and manage pressure injury-related pain effectively

    Health service provision and the use of pressure-redistributing devices: mixed methods study of community dwelling individuals with pressure injuries

    Get PDF
    © 2017 Informa UK Limited, trading as Taylor & Francis Group. Background: Health care within the home setting is a vital and growing component of pressure injury (PI) prevention and management. Objectives: To describe the use of health services and pressure-redistributing devices in community dwelling patients with PI’s. Design: Mixed-methods collective case study of a defined, diverse geographic postcode area in the United Kingdom. Methods: Quantitative retrospective analysis of electronic and paper medical records of adult PI patients from 2015 district nursing reports. Qualitative semi-structured interviews of community dwelling adult patients receiving, or received, treatment for PI in 2016. Results: Mandatory reports (n = 103) revealed that 90 patients were supplied with a variety of pressure-redistributing devices but only one-third of patients used the equipment as recommended. Qualitative interviews (n = 12), reported to COREQ guidelines, revealed that patients felt reliant on community health services, and were concerned about the consistency of their care. Conclusions: Authentic patient involvement is required to provide care and interventions that are acceptable to PI patients and can be incorporated into self-care strategies and effectively monitored

    3-O-Benzhydryl-2,5-dide­oxy-2,5-imino-2-C-methyl-l-lyxono-1,4-lactone

    Get PDF
    The title bicyclic lactone, C19H19NO3, is an inter­mediate in the synthesis of chiral α-methyl­prolines and branched C-methyl pyrrolidines; the absolute configuration was determined by the use of d-erythronolactone as the starting material. It exhibits no unusual crystal packing features, and each mol­ecule acts as a donor and acceptor for one C—H⋯O hydrogen bond

    6-De­oxy-α-l-talopyran­ose

    Get PDF
    X-ray crystallography showed that the title compound, C6H12O5, crystallizes in the α-pyran­ose form with the six-membered ring in a chair conformation. The crystal structure exists as a three-dimensional hydrogen-bonded network of mol­ecules with each mol­ecule acting as a donor and aceptor for four hydrogen bonds. The absolute configuration was determined by the use of l-fucose as starting material

    Addition of the mammalian target of rapamycin inhibitor, Everolimus, to consolidation therapy in acute myeloid leukaemia: experience from the UK NCRI AML17 trial

    Get PDF
    As part of the UK NCRI AML17 trial, adult patients with acute myeloid leukemia in remission could be randomized to receive the mammalian target of rapamycin inhibitor everolimus, sequentially with post-induction chemotherapy. Three hundred and thirty-nine patients were randomised (2:1) to receive everolimus or not for a maximum of 84 days between chemotherapy courses. The primary endpoint was relapse-free survival. At 5 years there was no difference in relapse-free survival [29% versus 40%; odds ratio 1.19 (0.9-1.59) P=0.2], cumulative incidence of relapse [60% versus 54%: odds ratio 1.12 (0.82-1.52): P=0.5] or overall survival [45% versus 58%: odds ratio 1.3 (0.94-1.81): P=0.11]. The independent Data Monitoring Committee advised study termination after randomization of 339 of the intended 600 patients because of excess mortality in the everolimus arm without any evidence of beneficial disease control. The delivery of the everolimus dose was variable, but there was no evidence of clinical benefit in patients with adequate dose delivery compared with no treatment. This study suggests that the addition of mammalian target of rapamycin inhibition to chemotherapy provides no benefit

    1-De­oxy-d-galactitol (l-fucitol)

    Get PDF
    1-De­oxy-d-galactitol, C6H14O5, exists in the crystalline form as hydrogen-bonded layers of mol­ecules running parallel to the ac plane, with each mol­ecule acting as a donor and acceptor of five hydrogen bonds

    Calcinosis in juvenile dermatomyositis is influenced by both anti-NXP2 autoantibody status and age at disease onset.

    Get PDF
    Calcinosis is a major cause of morbidity in JDM and has previously been linked to anti-NXP2 autoantibodies, younger age at disease onset and more persistent disease activity. This study aimed to investigate the clinical associations of anti-NXP2 autoantibodies in patients with JDM stratified by age at disease onset
    corecore