1,348 research outputs found

    G4-DNA formation in the HRAS promoter and rational design of decoy oligonucleotides for cancer therapy.

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    HRAS is a proto-oncogene involved in the tumorigenesis of urinary bladder cancer. In the HRAS promoter we identified two G-rich elements, hras-1 and hras-2, that fold, respectively, into an antiparallel and a parallel quadruplex (qhras-1, qhras-2). When we introduced in sequence hras-1 or hras-2 two point mutations that block quadruplex formation, transcription increased 5-fold, but when we stabilized the G-quadruplexes by guanidinium phthalocyanines, transcription decreased to 20% of control. By ChIP we found that sequence hras-1 is bound only by MAZ, while hras-2 is bound by MAZ and Sp1: two transcription factors recognizing guanine boxes. We also discovered by EMSA that recombinant MAZ-GST binds to both HRAS quadruplexes, while Sp1-GST only binds to qhras-1. The over-expression of MAZ and Sp1 synergistically activates HRAS transcription, while silencing each gene by RNAi results in a strong down-regulation of transcription. All these data indicate that the HRAS G-quadruplexes behave as transcription repressors. Finally, we designed decoy oligonucleotides mimicking the HRAS quadruplexes, bearing (R)-1-O-[4-(1-Pyrenylethynyl) phenylmethyl] glycerol and LNA modifications to increase their stability and nuclease resistance (G4-decoys). The G4-decoys repressed HRAS transcription and caused a strong antiproliferative effect, mediated by apoptosis, in T24 bladder cancer cells where HRAS is mutated

    Abnormal increase in urinary aquaporin-2 excretion in response to hypertonic saline in essential hypertension

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    <p>Abstract</p> <p>Background</p> <p>Dysregulation of the expression/shuttling of the aquaporin-2 water channel (AQP2) and the epithelial sodium channel (ENaC) in renal collecting duct principal cells has been found in animal models of hypertension. We tested whether a similar dysregulation exists in essential hypertension.</p> <p>Methods</p> <p>We measured urinary excretion of AQP2 and ENaC β-subunit corrected for creatinine (u-AQP2<sub>CR</sub>, u-ENaC<sub>β-CR</sub>), prostaglandin E2 (u-PGE<sub>2</sub>) and cyclic AMP (u-cAMP), fractional sodium excretion (FE<sub>Na</sub>), free water clearance (C<sub>H2O</sub>), as well as plasma concentrations of vasopressin (AVP), renin (PRC), angiotensin II (Ang II), aldosterone (Aldo), and atrial and brain natriuretic peptide (ANP, BNP) in 21 patients with essential hypertension and 20 normotensive controls during 24-h urine collection (baseline), and after hypertonic saline infusion on a 4-day high sodium (HS) diet (300 mmol sodium/day) and a 4-day low sodium (LS) diet (30 mmol sodium/day).</p> <p>Results</p> <p>At baseline, no differences in u-AQP2<sub>CR </sub>or u-ENaC<sub>β-CR </sub>were measured between patients and controls. U-AQP2<sub>CR </sub>increased significantly more after saline in patients than controls, whereas u-ENaC<sub>β-CR </sub>increased similarly. The saline caused exaggerated natriuretic increases in patients during HS intake. Neither baseline levels of u-PGE<sub>2</sub>, u-cAMP, AVP, PRC, Ang II, Aldo, ANP, and BNP nor changes after saline could explain the abnormal u-AQP2<sub>CR </sub>response.</p> <p>Conclusions</p> <p>No differences were found in u-AQP2<sub>CR </sub>and u-ENaC<sub>β-CR </sub>between patients and controls at baseline. However, in response to saline, u-AQP2<sub>CR </sub>was abnormally increased in patients, whereas the u-ENaC<sub>β-CR </sub>response was normal. The mechanism behind the abnormal AQP2 regulation is not clarified, but it does not seem to be AVP-dependent.</p> <p>Clinicaltrial.gov identifier</p> <p><a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=00345124">NCT00345124</a>.</p

    Abnormal function of the vasopressin-cyclic-AMP-aquaporin2 axis during urine concentrating and diluting in patients with reduced renal function. A case control study

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    <p>Abstract</p> <p>Background</p> <p>The kidneys ability to concentrate and dilute urine is deteriorated during progressive renal insufficiency. We wanted to test the hypothesis that these phenomena could be attributed to an abnormal function of the principal cells in the distal part of the nephron.</p> <p>Methods</p> <p>Healthy control subjects and patients with chronic kidney diseases were studied. Group 1 comprised healthy subjects, n = 10. Groups 2-4 comprised patients with chronic kidney disease (Group 2, n = 14, e-GFR ? 90 m1/min; Group 3, n = 11, 60 m1/min ? e-GFR < 90 ml/min; and Group 4, n = 16, 15 ml/min ? e-GFR < 60 ml/min). The subjects collected urine during 24 hours. A urine concentrating test was done by thirsting during the following 12 hours. Thereafter, a urine diluting test was performed with a water load of 20 ml/kg body weight. The effect variables were urinary excretions of aquaporin2 (u-AQP2), cyclic-AMP (u-c-AMP), urine volume (UV), free water clearance (C<sub>H2O</sub>), urine osmolarity (u-Osm), and plasma arginine vasopressin (p-AVP).</p> <p>Results</p> <p>After fluid deprivation, u-Osm increased. In all groups, UV and C<sub>H2O </sub>decreased and u-AQP2 and u-c-AMP increased in Groups 1 and 2, but were unchanged in Group 3 and 4. P-AVP was significantly higher in Group 4 than in the other groups. During urine diluting, UV and C<sub>H2O </sub>reached significantly higher levels in Groups 1-3 than Group 4. Both before and after water loading, u-AQP2 and p-AVP were significantly higher and u-c-AMP was significantly lower in Group 4 than the other groups. Estimated-GFR was correlated negatively to p-AVP and positively to u-c-AMP.</p> <p>Conclusions</p> <p>Patients with moderately severe chronic kidney disease have a reduced renal concentrating and diluting capacity compared to both patients with milder chronic kidney disease and healthy control subjects. These phenomena can be attributed, at least partly, to an abnormally decreased response in the AVP-c-AMP-AQP2 axis.</p> <p>ClinicalTrials.Gov Identifier: NCT00313430</p

    Increased renal sodium absorption by inhibition of prostaglandin synthesis during fasting in healthy man. A possible role of the epithelial sodium channels

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    <p>Abstract</p> <p>Background</p> <p>Treatment with prostaglandin inhibitors can reduce renal function and impair renal water and sodium excretion. We tested the hypotheses that a reduction in prostaglandin synthesis by ibuprofen treatment during fasting decreased renal water and sodium excretion by increased absorption of water and sodium via the aquaporin2 water channels and the epithelial sodium channels.</p> <p>Methods</p> <p>The effect of ibuprofen, 600 mg thrice daily, was measured during fasting in a randomized, placebo-controlled, double-blinded crossover study of 17 healthy humans. The subjects received a standardized diet on day 1, fasted at day 2, and received an IV infusion of 3% NaCl on day 3. The effect variables were urinary excretions of aquaporin2 (u-AQP2), the beta-fraction of the epithelial sodium channel (u-ENaCbeta), cyclic-AMP (u-cAMP), prostaglandin E2 (u-PGE2). Free water clearance (CH2O), fractional excretion of sodium (FENa), and plasma concentrations of vasopressin, angiotensin II, aldosterone, atrial-, and brain natriuretic peptide.</p> <p>Results</p> <p>Ibuprofen decreased u-AQP2, u-PGE2, and FENa at all parts of the study. During the same time, ibuprofen significantly increased u-ENaCbeta. Ibuprofen did not change the response in p-AVP, u-c-AMP, urinary output, and free water clearance during any of these periods. Atrial-and brain natriuretic peptide were higher.</p> <p>Conclusion</p> <p>During inhibition of prostaglandin synthesis, urinary sodium excretion decreased in parallel with an increase in sodium absorption and increase in u-ENaCbeta. U-AQP2 decreased indicating that water transport via AQP2 fell. The vasopressin-c-AMP-axis did not mediate this effect, but it may be a consequence of the changes in the natriuretic peptide system and/or the angiotensin-aldosterone system</p> <p>Trial Registration</p> <p>Clinical Trials Identifier: NCT00281762</p

    'I'm sorry to hear that'-Empathy and Empathic Dissonance : the Perspectives of PA Students

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    Context: Our understanding of clinical empathy could be enhanced through qualitative research-research currently under-represented in the field. Physician associates within the UK undergo an intensive 2-year postgraduate medical education. As a new group of health professionals, they represent a fresh pair of eyes through which to examine clinical empathy, its nature and teaching. Methods: Working with a constructivist paradigm, utilising grounded theory methodology, researchers studied 19 purposively sampled physician associate students in two UK medical schools. One-to-one semi-structured interviews were transcribed verbatim. Data were analysed using a grounded theory approach. Results: The global themes were the pathways to empathy, empathy modifiers and empathic dissonance a novel term to describe the discomfort students experience when pressurised into making empathic statements they don't sincerely feel. Students preferred using non-verbal over verbal expressions of empathy. A conceptual model is proposed. The more substantial empathic pathway, affective empathy, involves input from the heart. An alternative empathy, more constrained, comes from the head: cognitive empathy was considered a solution to time pressure and emotional burden. Formal teaching establishes empathic dissonance, a problem which stems from over-reliance on the empathic statement as the means to deliver clinical empathy. Conclusions: This study furthers our understanding of the construct and teaching of empathy. It identifies empathic barriers, especially time pressure. It proposes a novel concept-empathic dissonance-a concept that challenges medical educationalists to reframe future empathy teaching

    Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx)

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    Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-old vs. >2-year-old females). In general, the breeding proportion varied between age classes and study sites, whereas we did not detect such variation in litter size. The lack of differences in litter sizes among age classes is at odds with most findings in large mammals, and we argue that this is because the level of prenatal investment is relatively low in felids compared to their substantial levels of postnatal care

    The Difference in Pharmacists’ Interventions across the Diverse Settings in a Children’s Hospital

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    Aims: This study aimed to document and compare the nature of clinical pharmacists’ interventions made in different practice settings within a children’s hospital. Methods: The primary investigator observed and documented all clinical interventions performed by clinical pharmacists for between 35–37 days on each of the five study wards from the three practice settings, namely general medical, general surgical and hematology-oncology. The rates, types and significance of the pharmacists’ interventions in the different settings were compared.Results: A total of 982 interventions were documented, related to the 16,700 medication orders reviewed on the five wards in the three practice settings over the duration of the study. Taking medication histories and/or patient counselling were the most common pharmacists’ interventions in the general settings; constituting more than half of all interventions. On the Hematology-Oncology Ward the pattern was different with drug therapy changes being the most common interventions (n = 73/195, 37.4% of all interventions). Active interventions (pharmacists’ activities leading to a change in drug therapy) constituted less than a quarter of all interventions on the general medical and surgical wards compared to nearly half on thespecialty Hematology-Oncology Ward. The majority (n = 37/42, 88.1%) of a random sample of the active interventions reviewed were rated as clinically significant. Dose adjustment was the most frequent active interventions in the general settings, whilst drug addition constituted the most common active interventions on the Hematology-Oncology Ward. The degree of acceptance of pharmacists’ active interventions by prescribers was high (n = 223/244, 91.4%).Conclusions: The rate of pharmacists’ active interventions differed across different practice settings, being most frequent in the specialty hematology-oncology setting. The nature and type of the interventions documented in the hematologyoncology were also different compared to those in the general medical and surgical settings

    Intra-articular vs. systemic administration of etanercept in antigen-induced arthritis in the temporomandibular point. Part I: histological effects

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    <p>Abstract</p> <p>Background</p> <p>Temporomandibular joint (TMJ) arthritis in children causes alterations in craniomandibular growth. This abnormal growth may be prevented by an early anti-inflammatory intervention. We have previously shown that intra-articular (IA) corticosteroid reduces TMJ inflammation, but causes concurrent mandibular growth inhibition in young rabbits. Blockage of TNF-α has already proven its efficacy in children with juvenile idiopathic arthritis not responding to standard therapy. In this paper we evaluate the effect of IA etanercept compared to subcutaneous etanercept in antigen-induced TMJ-arthritis in rabbits on histological changes using histomorphometry and stereology. This article presents the data and discussion on the anti-inflammatory effects of systemic and IA etanercept. In Part II the data on the effects of systemic and IA etanercept on facial growth are presented.</p> <p>Methods</p> <p>Forty-two rabbits (10 weeks old) pre-sensitized with ovalbumin and locally induced inflammation in the temporomandibular joints were divided into three groups: a placebo group receiving IA saline injections in both joints one week after arthritis induction (n = 14), an IA etanercept group receiving 0.1 mg/kg etanercept per joint one week after arthritis induction (n = 14) and a systemic etanercept group receiving 0.8 mg/kg etanercept weekly throughout the 12-week study (n = 14). Arthritis was maintained by giving four inductions three weeks apart. Additional IA saline or etanercept injections were also given one week after the re-inductions. Histomorphometric and unbiased stereological methods (optical fractionator) were used to assess and estimate the inflammation in the joints.</p> <p>Results</p> <p>The histomorphometry showed synovial proliferation in all groups. The plasma cell count obtained by the optical fractionator was significantly reduced when treating with systemic etanercept but not with IA etanercept. Semi-quantitative assessments of synovial proliferation and subsynovial inflammation also showed reduced inflammation in the systemic etanercept group. However, the thickness of the synovial lining and volume of the subsynovial connective tissue showed no differences between the groups.</p> <p>Conclusion</p> <p>An anti-inflammatory effect of systemic etanercept on the synovial tissues in the temporomandibular joint was shown. However, IA etanercept at the given dose had no significant effect on the severity of chronic inflammation on the parameters here tested in ovalbumin antigen-induced arthritis.</p

    Posttraumatic Stress Disorder Prevalence and Risk of Recurrence in Acute Coronary Syndrome Patients: A Meta-analytic Review

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    BACKGROUND:Acute coronary syndromes (ACS; myocardial infarction or unstable angina) can induce posttraumatic stress disorder (PTSD), and ACS-induced PTSD may increase patients' risk for subsequent cardiac events and mortality. OBJECTIVE:To determine the prevalence of PTSD induced by ACS and to quantify the association between ACS-induced PTSD and adverse clinical outcomes using systematic review and meta-analysis. DATA SOURCES:Articles were identified by searching Ovid MEDLINE, PsycINFO, and Scopus, and through manual search of reference lists. METHODOLOGY/PRINCIPAL FINDINGS:Observational cohort studies that assessed PTSD with specific reference to an ACS event at least 1 month prior. We extracted estimates of the prevalence of ACS-induced PTSD and associations with clinical outcomes, as well as study characteristics. We identified 56 potentially relevant articles, 24 of which met our criteria (N = 2383). Meta-analysis yielded an aggregated prevalence estimate of 12% (95% confidence interval [CI], 9%-16%) for clinically significant symptoms of ACS-induced PTSD in a random effects model. Individual study prevalence estimates varied widely (0%-32%), with significant heterogeneity in estimates explained by the use of a screening instrument (prevalence estimate was 16% [95% CI, 13%-20%] in 16 studies) vs a clinical diagnostic interview (prevalence estimate was 4% [95% CI, 3%-5%] in 8 studies). The aggregated point estimate for the magnitude of the relationship between ACS-induced PTSD and clinical outcomes (ie, mortality and/or ACS recurrence) across the 3 studies that met our criteria (N = 609) suggested a doubling of risk (risk ratio, 2.00; 95% CI, 1.69-2.37) in ACS patients with clinically significant PTSD symptoms relative to patients without PTSD symptoms. CONCLUSIONS/SIGNIFICANCE:This meta-analysis suggests that clinically significant PTSD symptoms induced by ACS are moderately prevalent and are associated with increased risk for recurrent cardiac events and mortality. Further tests of the association of ACS-induced PTSD and clinical outcomes are needed
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