C3G mediated suppression of malignant transformation involves activation of PP2A phosphatases at the subcortical actin cytoskeleton

In previous work, we demonstrated that C3G suppresses Ras oncogenic transformation by a mechanism involving inhibition of ERK phosphorylation. Here we present evidences indicating that this suppression mechanism is mediated, at least in part, by serine/threonine phosphatases of the PP2A family. Thus: (i) ectopic expression of C3G or C3GΔCat (mutant lacking the GEF activity) increases specific ERK-associated PP2A phosphatase activities; (ii) C3G and PP2A interact, as demonstrated by immunofluorescence and co-immunoprecipitation experiments; (iii) association between PP2A and MEK or ERK increases in C3G overexpressing cells; (iv) phosphorylated-inactive PP2A level decreases in C3G expressing clones and, most importantly, (v) okadaic acid reverts the inhibitory effect of C3G on ERK phosphorylation. Moreover, C3G interacts with Ksr-1, a scaffold protein of the Ras-ERK pathway that also associates with PP2A. The fraction of C3G involved in transformation suppression is restricted to the subcortical actin cytoskeleton where it interacts with actin. Furthermore, the association between C3G and PP2A remains stable even after cytoskeleton disruption with cytochalasin D, suggesting that the three proteins form a complex at this subcellular compartment. Finally, C3G- and C3GΔCat-mediated inhibition of ERK phosphorylation is reverted by incubation with cytochalasin D. We hypothesize that C3G triggers PP2A activation and binding to MEK and ERK at the subcortical actin cytoskeleton, thus favouring ERK dephosphorylation. © 2007 Elsevier Inc. All rights reserved.This work was supported by grants SAF2003-04177 andGEN2003- 20239-C06-02 from MEC, Spain, FIS-FEDERPI030651, PI041324 and PI061274 from ISCIII,MSC, Spain, as well as institutional support from Redes Temáticas (C03/10 and RD06/0020/0000) de investigación en cáncer from ISCIII, MSC, Spain. S. M-E is a postodoctoral fellow supported by grant GEN2003-20239-C06-02. C.G. was supported by the Ramón y Cajal Program from the Spanish Ministry of Education.Peer Reviewe

Results of lumbar interbody fusion in elderly patients with lumbar spinal stenosis associated with cauda equina syndrome

Background: Currently, there are no clear recommendations on the timing of surgical intervention for the slow development of cauda equina syndrome (CES) against the background of lumbar spinal stenosis (LSS) at the lumbar level in elderly patients. The information on the long-term effectiveness of decompressive and stabilizing interventions (DSI) in the lumbar spine in this pathology is also limited.Objective: To conduct a comparative analysis of the results of surgical treatment of elderly patients with LSS associated with CES after open and low-traumatic DSI.Material and methods: The retrospective study included 37 patients operated on between 2000 and 2020 for CES caused by LSS. Two groups were distinguished: in the first group (n = 17), an open DSI was performed with the median approach, in the second group (n = 20) a low-traumatic DSI was performed according to the author’s method. Technical features of interventions and specificity of the postoperative period, preoperative instrumental data, clinical parameters in dynamics, and complications were compared.Results: In a comparative analysis in the group of patients operated on with author’s low-traumatic DSI, smaller parameters were registered: the duration of the operation (p = 0.02), the blood loss (p = 0.003), the duration of inpatient treatment (p = 0.002), and the postoperative need for opioid analgesics (p < 0.05). In catamnesis, statistically significantly better clinical parameters of bladder sphincter control (p = 0.02) and motor function recovery (p = 0.01), Oswestry Disability Index (ODI) (p = 0.03) and the Short Form-36 (SF-36) (p = 0.01) were observed in patients of the group II, compared with the group I. A greater number of complications were noticed in the group of open DSI (p = 0.003), with a comparable frequency of reoperations in the follow-up period (p = 0.79).Conclusion: In elderly patients with CES-associated LSS, the advantages of the author’s low-traumatic DSI in comparison with open DSI were established of less blood loss and duration of hospitalization, low need for postoperative analgesia, the minimum number of complications, and the dynamics of neurological symptoms, better recovery of ODI and SF-36 in catamnesis

Principles of meiotic chromosome assembly revealed in S. cerevisiae

During meiotic prophase, chromosomes organise into a series of chromatin loops emanating from a proteinaceous axis, but the mechanisms of assembly remain unclear. Here we use Saccharomyces cerevisiae to explore how this elaborate three-dimensional chromosome organisation is linked to genomic sequence. As cells enter meiosis, we observe that strong cohesin-dependent grid-like Hi-C interaction patterns emerge, reminiscent of mammalian interphase organisation, but with distinct regulation. Meiotic patterns agree with simulations of loop extrusion with growth limited by barriers, in which a heterogeneous population of expanding loops develop along the chromosome. Importantly, CTCF, the factor that imposes similar features in mammalian interphase, is absent in S. cerevisiae, suggesting alternative mechanisms of barrier formation. While grid-like interactions emerge independently of meiotic chromosome synapsis, synapsis itself generates additional compaction that matures differentially according to telomere proximity and chromosome size. Collectively, our results elucidate fundamental principles of chromosome assembly and demonstrate the essential role of cohesin within this evolutionarily conserved process

SMC complexes differentially compact mitotic chromosomes according to genomic context

Structural maintenance of chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modelling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids, while condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate that this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead, it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes

Epidemiological and clinical peculiarities of bronchial asthma among children in urban and rural regions(in example of St-Petersburg and Leningradsky region)

The study was performed to determine the prevalence of bronchial asthma among children in St.-Petersburg and Leningradsky region and to research risk factors of this disease. It is carried out review 1502 children in St.-Petersburg and 1522 children in Leningradsky region. The analysis of the data has shown that the prevalence of bronchial asthma have made 7,4% in St.-Petersburg and 3,7% in Leningradsky region (p<0,001). Among children with bronchial asthma the boys are prevailed in both regions. This study confirmed that both genetic and environmental factors are associated with clinical asthma among children. The analysis of risk factors among children of urban and rural areas has shown, that the most important ones are: inheritable predisposition to asthma (OR=3,7-8,9 in St.-Petersburg and OR=8,2-13,6 in Leningradsky region), parents atopy (OR=3,9-5,5 in St.-Petersburg and OR=5,8-5,9 in Leningradsky region), presence of pets at home (OR=1,6 in St.-Petersburg and OR=2,8 in Leningradsky region). The results are received allow to improve planning health services of the children's population.Целью настоящего исследования явилось определение распространенности и факторов риска формирования бронхиальной астмы у детей, проживающих в Санкт-Петербурге и Ленинградской области. Проведено анкетирование 1520 детей, проживающих в Санкт-Петербурге и 1502 детей, проживающих в Ленинградской области. Анализ анкет показал, что распространенность бронхиальной астмы у детей в Санкт-Петербурге составила 7,4%, а в Ленинградской области 3,7% (р<0.001). В обеих изучаемых группах преобладали мальчики. Выявлены эндогенные и экзогенные факторы риска формирования бронхиальной астмы у детей. Анализ факторов риска заболевания у детей, проживающих в городском и сельском регионах показал, что ведущее значение имели: наследственная отягощенностъ по бронхиальной астме (OR=3,7-8,9 в Санкт- Петербурге и OR=8,2-13,6 в Ленинградской области): аллергические заболевания у родителей (OR=3,9-5,5 в Санкт-Петербурге и OR= 5,8-5,9 в Ленинградской области): содержание домашних животных (OR=1,6 в Санкт-Петербурге и OR=2,8 в Ленинградской области). Результаты исследования позволяют улучшить планирование лечебно-профилактических мероприятий в детской популяции

Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial

IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved

Extended Thromboprophylaxis with Betrixaban in Acutely Ill Medical Patients

Background Patients with acute medical illnesses are at prolonged risk for venous thrombosis. However, the appropriate duration of thromboprophylaxis remains unknown. Methods Patients who were hospitalized for acute medical illnesses were randomly assigned to receive subcutaneous enoxaparin (at a dose of 40 mg once daily) for 10±4 days plus oral betrixaban placebo for 35 to 42 days or subcutaneous enoxaparin placebo for 10±4 days plus oral betrixaban (at a dose of 80 mg once daily) for 35 to 42 days. We performed sequential analyses in three prespecified, progressively inclusive cohorts: patients with an elevated d-dimer level (cohort 1), patients with an elevated d-dimer level or an age of at least 75 years (cohort 2), and all the enrolled patients (overall population cohort). The statistical analysis plan specified that if the between-group difference in any analysis in this sequence was not significant, the other analyses would be considered exploratory. The primary efficacy outcome was a composite of asymptomatic proximal deep-vein thrombosis and symptomatic venous thromboembolism. The principal safety outcome was major bleeding. Results A total of 7513 patients underwent randomization. In cohort 1, the primary efficacy outcome occurred in 6.9% of patients receiving betrixaban and 8.5% receiving enoxaparin (relative risk in the betrixaban group, 0.81; 95% confidence interval [CI], 0.65 to 1.00; P=0.054). The rates were 5.6% and 7.1%, respectively (relative risk, 0.80; 95% CI, 0.66 to 0.98; P=0.03) in cohort 2 and 5.3% and 7.0% (relative risk, 0.76; 95% CI, 0.63 to 0.92; P=0.006) in the overall population. (The last two analyses were considered to be exploratory owing to the result in cohort 1.) In the overall population, major bleeding occurred in 0.7% of the betrixaban group and 0.6% of the enoxaparin group (relative risk, 1.19; 95% CI, 0.67 to 2.12; P=0.55). Conclusions Among acutely ill medical patients with an elevated d-dimer level, there was no significant difference between extended-duration betrixaban and a standard regimen of enoxaparin in the prespecified primary efficacy outcome. However, prespecified exploratory analyses provided evidence suggesting a benefit for betrixaban in the two larger cohorts. (Funded by Portola Pharmaceuticals; APEX ClinicalTrials.gov number, NCT01583218. opens in new tab.

Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design

A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme