159 research outputs found

    The implications of autonomy: Viewed in the light of efforts to uphold patients dignity and integrity

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    This article focuses on Danish patients’ experience of autonomy and its interplay with dignity and integrity in their meeting with health professionals. The aim is to chart the meanings and implications of autonomy for persons whose illness places them in a vulnerable life situation. The interplay between autonomy and personal dignity in the meeting with health care staff are central concepts in the framework. Data collection and findings are based on eight qualitative semi-structured interviews with patients. Patients with acute, chronic, and life threatening diseases were represented including surgical as well as medical patients. The values associated with autonomy are in many ways vitalising, but may become so dominant, autonomy seeking, and pervasive that the patient's dignity is affected. Three types of patient behaviour were identified. (1) The proactive patient: Patients feel that they assume responsibility for their own situation, but it may be a responsibility that they find hard to bear. (2) The rejected patient: proactive patients take responsibility on many occasions but very active patients are at risk of being rejected with consequences for their dignity. (3) The knowledgeable patient: when patients are health care professionals, the patient's right of self-determination was managed in a variety of ways, sometimes the patient's right of autonomy was treated in a dignified way but the opposite was also evident. In one way, patients are active and willing to take responsibility for themselves, and at the same time they are “forced” to do so by health care staff. Patients would like health professionals to be more attentive and proactive

    Evaluation of Functional Erythropoietin Receptor Status in Skeletal Muscle In Vivo: Acute and Prolonged Studies in Healthy Human Subjects

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    BACKGROUND: Erythropoietin receptors have been identified in human skeletal muscle tissue, but downstream signal transduction has not been investigated. We therefore studied in vivo effects of systemic erythropoietin exposure in human skeletal muscle. METHODOLOGY/PRINCIPAL FINDINGS: The protocols involved 1) acute effects of a single bolus injection of erythropoietin followed by consecutive muscle biopsies for 1-10 hours, and 2) a separate study with prolonged administration for 16 days with biopsies obtained before and after. The presence of erythropoietin receptors in muscle tissue as well as activation of Epo signalling pathways (STAT5, MAPK, Akt, IKK) were analysed by western blotting. Changes in muscle protein profiles after prolonged erythropoietin treatment were evaluated by 2D gel-electrophoresis and mass spectrometry. The presence of the erythropoietin receptor in skeletal muscle was confirmed, by the M20 but not the C20 antibody. However, no significant changes in phosphorylation of the Epo-R, STAT5, MAPK, Akt, Lyn, IKK, and p70S6K after erythropoietin administration were detected. The level of 8 protein spots were significantly altered after 16 days of rHuEpo treatment; one isoform of myosin light chain 3 and one of desmin/actin were decreased, while three isoforms of creatine kinase and two of glyceraldehyd-3-phosphate dehydrogenase were increased. CONCLUSIONS/SIGNIFICANCE: Acute exposure to recombinant human erythropoietin is not associated by detectable activation of the Epo-R or downstream signalling targets in human skeletal muscle in the resting situation, whereas more prolonged exposure induces significant changes in the skeletal muscle proteome. The absence of functional Epo receptor activity in human skeletal muscle indicates that the long-term effects are indirect and probably related to an increased oxidative capacity in this tissue

    Hypoxic regulation of RIOK3 is a major mechanism for cancer cell invasion and metastasis.

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    Hypoxia is a common feature of locally advanced breast cancers that is associated with increased metastasis and poorer survival. Stabilisation of hypoxia-inducible factor-1α (HIF1α) in tumours causes transcriptional changes in numerous genes that function at distinct stages of the metastatic cascade. We demonstrate that expression of RIOK3 (RIght Open reading frame kinase 3) was increased during hypoxic exposure in an HIF1α-dependent manner. RIOK3 was localised to distinct cytoplasmic aggregates in normoxic cells and underwent redistribution to the leading edge of the cell in hypoxia with a corresponding change in the organisation of the actin cytoskeleton. Depletion of RIOK3 expression caused MDA-MB-231 to become elongated and this morphological change was due to a loss of protraction at the trailing edge of the cell. This phenotypic change resulted in reduced cell migration in two-dimensional cultures and inhibition of cell invasion through three-dimensional extracellular matrix. Proteomic analysis identified interactions of RIOK3 with actin and several actin-binding factors including tropomyosins (TPM3 and TPM4) and tropomodulin 3. Depletion of RIOK3 in cells resulted in fewer and less organised actin filaments. Analysis of these filaments showed reduced association of TPM3, particularly during hypoxia, suggesting that RIOK3 regulates actin filament specialisation. RIOK3 depletion reduced the dissemination of MDA-MB-231 cells in both a zebrafish model of systemic metastasis and a mouse model of pulmonary metastasis. These findings demonstrate that RIOK3 is necessary for maintaining actin cytoskeletal organisation required for migration and invasion, biological processes that are necessary for hypoxia-driven metastasis

    Interconversion of Functional Motions between Mesophilic and Thermophilic Adenylate Kinases

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    Dynamic properties are functionally important in many proteins, including the enzyme adenylate kinase (AK), for which the open/closed transition limits the rate of catalytic turnover. Here, we compare our previously published coarse-grained (double-well Gō) simulation of mesophilic AK from E. coli (AKmeso) to simulations of thermophilic AK from Aquifex aeolicus (AKthermo). In AKthermo, as with AKmeso, the LID domain prefers to close before the NMP domain in the presence of ligand, but LID rigid-body flexibility in the open (O) ensemble decreases significantly. Backbone foldedness in O and/or transition state (TS) ensembles increases significantly relative to AKmeso in some interdomain backbone hinges and within LID. In contact space, the TS of AKthermo has fewer contacts at the CORE-LID interface but a stronger contact network surrounding the CORE-NMP interface than the TS of AKmeso. A “heated” simulation of AKthermo at 375K slightly increases LID rigid-body flexibility in accordance with the “corresponding states” hypothesis. Furthermore, while computational mutation of 7 prolines in AKthermo to their AKmeso counterparts produces similar small perturbations, mutation of these sites, especially positions 8 and 155, to glycine is required to achieve LID rigid-body flexibility and hinge flexibilities comparable to AKmeso. Mutating the 7 sites to proline in AKmeso reduces some hinges' flexibilities, especially hinge 2, but does not reduce LID rigid-body flexibility, suggesting that these two types of motion are decoupled in AKmeso. In conclusion, our results suggest that hinge flexibility and global functional motions alike are correlated with but not exclusively determined by the hinge residues. This mutational framework can inform the rational design of functionally important flexibility and allostery in other proteins toward engineering novel biochemical pathways

    Multiscale Coarse-Graining of the Protein Energy Landscape

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    A variety of coarse-grained (CG) models exists for simulation of proteins. An outstanding problem is the construction of a CG model with physically accurate conformational energetics rivaling all-atom force fields. In the present work, atomistic simulations of peptide folding and aggregation equilibria are force-matched using multiscale coarse-graining to develop and test a CG interaction potential of general utility for the simulation of proteins of arbitrary sequence. The reduced representation relies on multiple interaction sites to maintain the anisotropic packing and polarity of individual sidechains. CG energy landscapes computed from replica exchange simulations of the folding of Trpzip, Trp-cage and adenylate kinase resemble those of other reduced representations; non-native structures are observed with energies similar to those of the native state. The artifactual stabilization of misfolded states implies that non-native interactions play a deciding role in deviations from ideal funnel-like cooperative folding. The role of surface tension, backbone hydrogen bonding and the smooth pairwise CG landscape is discussed. Ab initio folding aside, the improved treatment of sidechain rotamers results in stability of the native state in constant temperature simulations of Trpzip, Trp-cage, and the open to closed conformational transition of adenylate kinase, illustrating the potential value of the CG force field for simulating protein complexes and transitions between well-defined structural states

    Combination therapy with oral treprostinil for pulmonary arterial hypertension. A double-blind placebo-controlled clinical trial

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    Rationale: Oral treprostinil improves exercise capacity in patients with pulmonary arterial hypertension (PAH), but the effect on clinical outcomes was unknown. Objectives: To evaluate the effect of oral treprostinil compared with placebo on time to first adjudicated clinical worsening event in participants with PAH who recently began approved oral monotherapy. Methods: In this event-driven, double-blind study, we randomly allocated 690 participants (1:1 ratio) with PAH to receive placebo or oral treprostinil extended-release tablets three times daily. Eligible participants were using approved oral monotherapy for over 30 days before randomization and had a 6-minute-walk distance 150 m or greater. The primary endpoint was the time to first adjudicated clinical worsening event: death; hospitalization due to worsening PAH; initiation of inhaled or parenteral prostacyclin therapy; disease progression; or unsatisfactory long-term clinical response. Measurements and Main Results: Clinical worsening occurred in 26% of the oral treprostinil group compared with 36% of placebo participants (hazard ratio, 0.74; 95% confidence interval, 0.56–0.97; P = 0.028). Key measures of disease status, including functional class, Borg dyspnea score, and N-terminal pro–brain natriuretic peptide, all favored oral treprostinil treatment at Week 24 and beyond. A noninvasive risk stratification analysis demonstrated that oral treprostinil–assigned participants had a substantially higher mortality risk at baseline but achieved a lower risk profile from Study Weeks 12–60. The most common adverse events in the oral treprostinil group were headache, diarrhea, flushing, nausea, and vomiting. Conclusions: In participants with PAH, addition of oral treprostinil to approved oral monotherapy reduced the risk of clinical worsening. Clinical trial registered with www.clinicaltrials.gov (NCT01560624)

    Confrontation of fibroblasts with cancer cells in vitro: Gene network analysis of transcriptome changes and differential capacity to inhibit tumor growth

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    Background: There is growing evidence that emerging malignancies in solid tissues might be kept under control by physical intercellular contacts with normal fibroblasts. Methods: Here we characterize transcriptional landscapes of fibroblasts that confronted cancer cells. We studied four pairs of in vitro and ex vivo fibroblast lines which, within each pair, differed in their capacity to inhibit cancer cells. The natural process was modeled in vitro by confronting the fibroblasts with PC-3 cancer cells. Fibroblast transcriptomes were recorded by Affymetrix microarrays and then investigated using network analysis. Results: The network enrichment analysis allowed us to separate confrontation- and inhibition-specific components of the fibroblast transcriptional response. Confrontation-specific differences were stronger and were characterized by changes in a number of pathways, including Rho, the YAP/TAZ cascade, NF-kB, and TGF-beta signaling, as well as the transcription factor RELA. Inhibition-specific differences were more subtle and characterized by involvement of Rho signaling at the pathway level and by potential individual regulators such as IL6, MAPK8, MAP2K4, PRKCA, JUN, STAT3, and STAT5A. Conclusions: We investigated the interaction between cancer cells and fibroblasts in order to shed light on the potential mechanisms and explain the differential inhibitory capacity of the latter, which enabled both a holistic view on the process and details at the gene/protein level. The combination of our methods pointed to proteins, such as members of the Rho pathway, pro-inflammatory signature and the YAP1/TAZ cascade, that warrant further investigation via tools of experimental perturbation. We also demonstrated functional congruence between the in vitro and ex vivo models. © 2015 Alexeyenko et al
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