The MicroRNA and MessengerRNA Profile of the RNA-Induced Silencing Complex in Human Primary Astrocyte and Astrocytoma Cells

GW/P bodies are cytoplasmic ribonucleoprotein-rich foci involved in microRNA (miRNA)-mediated messenger RNA (mRNA) silencing and degradation. The mRNA regulatory functions within GW/P bodies are mediated by GW182 and its binding partner hAgo2 that bind miRNA in the RNA-induced silencing complex (RISC). To date there are no published reports of the profile of miRNA and mRNA targeted to the RISC or a comparison of the RISC-specific miRNA/mRNA profile differences in malignant and non-malignant cells.RISC mRNA and miRNA components were profiled by microarray analysis of malignant human U-87 astrocytoma cells and its non-malignant counterpart, primary human astrocytes. Total cell RNA as well as RNA from immunoprecipitated RISC was analyzed. The novel findings were fourfold: (1) miRNAs were highly enriched in astrocyte RISC compared to U-87 astrocytoma RISC, (2) astrocytoma and primary astrocyte cells each contained unique RISC miRNA profiles as compared to their respective cellular miRNA profiles, (3) miR-195, 10b, 29b, 19b, 34a and 455-3p levels were increased and the miR-181b level was decreased in U-87 astrocytoma RISC as compared to astrocyte RISC, and (4) the RISC contained decreased levels of mRNAs in primary astrocyte and U-87 astrocytoma cells.The observation that miR-34a and miR-195 levels were increased in the RISC of U-87 astrocytoma cells suggests an oncogenic role for these miRNAs. Differential regulation of mRNAs by specific miRNAs is evidenced by the observation that three miR34a-targeted mRNAs and two miR-195-targeted mRNAs were downregulated while one miR-195-targeted mRNA was upregulated. Biological pathway analysis of RISC mRNA components suggests that the RISC plays a pivotal role in malignancy and other conditions. This study points to the importance of the RISC and ultimately GW/P body composition and function in miRNA and mRNA deregulation in astrocytoma cells and possibly in other malignancies

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

D-dimer levels and risk of recurrence following provoked venous thromboembolism: findings from the RIETE registry

BACKGROUND: Patients with venous thromboembolism (VTE) secondary to transient risk factors may develop VTE recurrences after discontinuing anticoagulation. Identifying at-risk patients could help to guide the duration of therapy. METHODS: We used the RIETE database to assess the prognostic value of d-dimer testing after discontinuing anticoagulation to identify patients at increased risk for recurrences. Transient risk factors were classified as major (postoperative) or minor (pregnancy, oestrogen use, immobilization or recent travel). RESULTS: In December 2018, 1655 VTE patients with transient risk factors (major 460, minor 1195) underwent d-dimer measurements after discontinuing anticoagulation. Amongst patients with major risk factors, the recurrence rate was 5.74 (95% CI: 3.19-9.57) events per 100 patient-years in those with raised d-dimer levels and 2.68 (95% CI: 1.45-4.56) in those with normal levels. Amongst patients with minor risk factors, the rates were 7.79 (95% CI: 5.71-10.4) and 3.34 (95% CI: 2.39-4.53), respectively. Patients with major risk factors and raised d-dimer levels (n = 171) had a nonsignificantly higher rate of recurrences (hazard ratio [HR]: 2.14; 95% CI: 0.96-4.79) than those with normal levels. Patients with minor risk factors and raised d-dimer levels (n = 382) had a higher rate of recurrences (HR: 2.34; 95% CI: 1.51-3.63) than those with normal levels. On multivariate analysis, raised d-dimers (HR: 1.74; 95% CI: 1.09-2.77) were associated with an increased risk for recurrences in patients with minor risk factors, not in those with major risk factors. CONCLUSIONS: Patients with raised d-dimer levels after discontinuing anticoagulant therapy for VTE provoked by a minor transient risk factor were at an increased risk for recurrences.status: publishe

D-dimer levels and risk of recurrence following provoked venous thromboembolism: findings from the RIETE registry

Background: Patients with venous thromboembolism (VTE) secondary to transient risk factors may develop VTE recurrences after discontinuing anticoagulation. Identifying at-risk patients could help to guide the duration of therapy. Methods: We used the RIETE database to assess the prognostic value of d-dimer testing after discontinuing anticoagulation to identify patients at increased risk for recurrences. Transient risk factors were classified as major (postoperative) or minor (pregnancy, oestrogen use, immobilization or recent travel). Results: In December 2018, 1655 VTE patients with transient risk factors (major 460, minor 1195) underwent d-dimer measurements after discontinuing anticoagulation. Amongst patients with major risk factors, the recurrence rate was 5.74 (95% CI: 3.19\u20139.57) events per 100 patient-years in those with raised d-dimer levels and 2.68 (95% CI: 1.45\u20134.56) in those with normal levels. Amongst patients with minor risk factors, the rates were 7.79 (95% CI: 5.71\u201310.4) and 3.34 (95% CI: 2.39\u20134.53), respectively. Patients with major risk factors and raised d-dimer levels (n = 171) had a nonsignificantly higher rate of recurrences (hazard ratio [HR]: 2.14; 95% CI: 0.96\u20134.79) than those with normal levels. Patients with minor risk factors and raised d-dimer levels (n = 382) had a higher rate of recurrences (HR: 2.34; 95% CI: 1.51\u20133.63) than those with normal levels. On multivariate analysis, raised d-dimers (HR: 1.74; 95% CI: 1.09\u20132.77) were associated with an increased risk for recurrences in patients with minor risk factors, not in those with major risk factors. Conclusions: Patients with raised d-dimer levels after discontinuing anticoagulant therapy for VTE provoked by a minor transient risk factor were at an increased risk for recurrences

First three months of anticoagulation for venous thromboembolism in non-cancer patients: LMWH VS. VKAs. Findings from the RIETE registry

Background: The use of low-molecular-weight heparin (LMWH) for long-term therapy of venous thromboembolism (VTE) in patients without cancer has not been consistently evaluated. Methods: We used the data in the RIETE registry to compare the 3-month outcomes (VTE recurrences, major bleeding or death) in non-cancer patients with VTE, according to long-term therapy with LMWH or vitamin K antagonists (VKAs). Results: As of March 2018, 14,582 non-cancer patients with VTE had received initial therapy with LMWH and then switched to VKAs, while 9151 were prescribed LMWH for initial and long-term therapy. Overall, 11,494 had initially presented with pulmonary embolism (PE) and 12,239 with isolated deep vein thrombosis (DVT). Among 11,494 patients initially presenting with PE, 84 had VTE recurrences, 204 major bleeding and 406 died. Among 12,239 patients with isolated DVT, 133 developed VTE recurrences, 137 bled and 289 died. On propensity score analysis, PE patients on long-term LMWH therapy were at increased risk for PE recurrences (OR: 3.30; 95%CI: 1.67–6.48), major bleeding (OR: 1.68; 95%CI: 1.21–2.32) or death (OR: 3.16; 95%CI: 2.43–4.09) compared with those receiving VKAs. In patients with DVT, those on long-term LMWH also were at increased risk for PE recurrences (OR: 2.31; 95%CI: 1.13–4.73), major bleeding (OR 2.28; 95%CI: 1.51–3.44) or death (OR: 2.32; 95%CI: 1.54–3.51). Conclusions: In the RIETE non-cancer patients with VTE, long-term therapy with VKAs was associated with a lower risk for recurrences, major bleeding or death

Timing and characteristics of venous thromboembolism after noncancer surgery

Background: Venous thromboembolism (VTE) is a major cause of morbidity and mortality postoperatively. The use of pharmacologic prophylaxis is effective in reducing the incidence of VTE. However, the prophylaxis is often discontinued at hospital discharge, especially for those with benign disease. The implications of this practice are not known. We assessed the data from a large, ongoing registry regarding the time course of VTE and outcomes after noncancer surgery. Methods: We analyzed the RIETE (Computerized Registry on Venous Thromboembolism) registry, which includes data from consecutive patients with symptomatic confirmed VTE. In the present study, we focused on general surgical patients who had developed symptomatic postoperative VTE in the first 8 weeks after noncancer surgery. The main objective was to assess the interval between surgery and the occurrence of VTE. Additional variables included the clinical presentation associated with the event, the use of thrombosis prophylaxis, and unfavorable outcomes. Results: The data from 3296 patients were analyzed. The median time from surgery to the detection of VTE was 16 days (interquartile range, 8-30 days). Of the VTE events, 77% were detected after the first postoperative week and 27% after 4 weeks. Overall, 43.9% of the patients with VTE had received pharmacologic prophylaxis after surgery for a median of 8 days (interquartile range, 5-14 days), and three quarters of the VTE events were detected after pharmacologic prophylaxis had been discontinued. Overall, 54% of the patients with VTE had presented with pulmonary embolism. For 15% of the patients, the clinical outcome was unfavorable, including 4% who had died within 90 days. Conclusions: The risk of VTE after noncancer general surgery remains high for ≤2 months. More than one half of the patients had presented with symptomatic PE as the VTE event, and 15% had had unfavorable outcomes. Only 44% of these patients had received pharmacologic prophylaxis for around 1 week

A new role of AMP-activated protein kinase in regulating proliferation of mesenchymal stem cells

Purpose: Natriuretic peptides (NPs) administered during early reperfusion are protective in models of myocardial infarction. A previous study examining the endogenous components of B-type natriuretic peptide (BNP) protection of reperfused myocardium, implicated both sarcolemmal (s) KATP and mitochondrial (m) KATP channels. The indirect evidence characterising the relationship between BNP signalling and KATP was obtained using sulphonylurea receptor inhibitors in a rat isolated heart model of ischaemia-reperfusion injury. Here we seek to further examine the relationship between NPs and sKATP openings using single channel electrophysiology. Given our previous findings and the overarching consensus that cardioprotective autacoids open KATP channels, it was hypothesised that NPs elicit sKATP opening. Methods: Cardiomyocyte isolation. Left ventricular cardiomyocytes were isolated from male Sprague-Dawley rat hearts subjected to enzymatic digestion with Liberase Blendzyme DL. Cardiomyocytes were cultured overnight in Medium 199, prior to patch clamp. Single channel patch clamp. Single channel recordings at room temperature (22°C) were made from cell attached patches bathed in Na+ Locke, pH 7.2. The recording pipette contained high KCl (140 mM), pH 7.2. Recordings (45 sec) were made over a range of patch potentials (0, -30, -60, -90, -120 mV), in the absence (control) and in the presence of bath applied BNP (10, 100 nM and 1 µM), pinacidil (200 µM) or pinacidil vehicle (DMSO, 0.25%). Recordings were also made with BNP and pinacidil applied concomitantly. Data are mean ± S.E.M. Results: The current voltage relationship of sKATP under control conditions was linear at –ve patch potentials, the mean conductance being 52.9 ± 1.8 pS (n = 18 hearts, n = 35 cells). Pinacidil caused a four fold increase in sKATP open probability compared to control. Mean channel conductance in the presence of pinacidil was 59.9 ± 1.9 pS (n = 16 hearts, n = 44 cells). Interestingly BNP at all concentrations had negligible effects on sKATP open probability and unitary conductance. However, BNP at all concentrations and patch potentials inhibited pinacidil induced sKATP openings, restoring channel open probability to baseline. Conclusion: These data illustrate the inhibitory effect of NP signalling on sKATP function in the cardiomyocyte under normoxia. They are concordant with the inhibitory effect of atrial NP on KATP in the pancreatic beta cell, but are in apparent conflict with the current cardioprotection paradigm. However, differential effects on sKATP and mKATP and the effects of hypoxia-reoxygenation require further exploration

Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

Background: Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE ESUS trial. Methods: NAVIGATE ESUS was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy. Findings: Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE ESUS with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with ESUS who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted. Funding: Bayer and Janssen