502 research outputs found

    Yeast axial-element protein, Red1, binds SUMO chains to promote meiotic interhomologue recombination and chromosome synapsis

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    The synaptonemal complex (SC) is a tripartite protein structure consisting of two parallel axial elements (AEs) and a central region. During meiosis, the SC connects paired homologous chromosomes, promoting interhomologue (IH) recombination. Here, we report that, like the CE component Zip1, Saccharomyces cerevisiae axial-element structural protein, Red1, can bind small ubiquitin-like modifier (SUMO) polymeric chains. The Red1–SUMO chain interaction is dispensable for the initiation of meiotic DNA recombination, but it is essential for Tel1- and Mec1-dependent Hop1 phosphorylation, which ensures IH recombination by preventing the inter-sister chromatid DNA repair pathway. Our results also indicate that Red1 and Zip1 may directly sandwich the SUMO chains to mediate SC assembly. We suggest that Red1 and SUMO chains function together to couple homologous recombination and Mec1–Tel1 kinase activation with chromosome synapsis during yeast meiosis

    Outcome of Classical Hodgkin’s Lymphoma Treatment Based on High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation: The Experience in the NI Pirogov Russian National Medical Center of Surgery

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    Aim. To estimate the long-term outcome of the programmed treatment of classical Hodgkin’s lymphoma (cHL) including high-dose chemotherapy (HDCT) and autologous hematopoietic stem cell transplantation (auto-HSCT) as well as the effect of various factors on the achieved results in a single-center study. Materials & Methods. In the A.A. Maksimov Clinical Center of Hematology and Cellular Therapy of the NI Pirogov Russian National Medical Center of Surgery 260 cHL patients received HDCT combined with auto-HSCT within the period from December 2006 to March 2017. The median age was 29 years (range 17–62). The study included 40 % men (n = 104), and 60 % women (n = 156). The median pretransplantation chemotherapy line was 3 (range 2–9). At this stage, prior to auto-HSCT, complete remission (CR) rate was 26.5 %, partial remission (PR) rate was 52.3 %, disease stabilisation rate was 13.5 %. HDCT with auto-HSCT was applied beyond progression as a salvage therapy in 7.7 % of patients. In 79.6 % of patients the standard BEAM and CBV conditioning regimens were used. Results. After HDCT combined with auto-HSCT overall 5-year survival (OS) of 260 cHL patients was 74 %, and 5-year progression-free survival (PFS) was 48 %, which corresponds to the results of some international studies. 5-year OS rates were significantly higher after HDCT and auto-HSCT performed during the first CR or PR (85 %) vs the second and subsequent CR and PR (71 %). Neither gender (p = 0.4) nor ECOG status (p = 0.2) effects on OS and PFS were revealed. 5-year OS rates were significantly higher after HDCT and auto-HSCT performed during CR or PR (82 %) vs disease stabilisation and progression (54 %) as well as upon achieving CR (93 %) vs PR (77 %). Conclusion. In cHL tumor sensitivity to chemotherapy is the essential indication for HDCT combined with auto-HSCT. The optimal time for HDCT and auto-HSCT in cHL is the first CR/PR, and the best treatment outcome is achieved in patients with complete response prior to HDCT and auto-HSCT

    Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology

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    A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel

    A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk

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    Binary and multiple star systems are a frequent outcome of the star formation process, and as a result, almost half of all sun-like stars have at least one companion star. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large scale fragmentation of turbulent gas cores and filaments or smaller scale fragmentation of a massive protostellar disk due to gravitational instability. Observational evidence for turbulent fragmentation on scales of >>1000~AU has recently emerged. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems. The triple protostar system L1448 IRS3B is an ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in an early phase of the star formation process, likely less than 150,000 years in age, and all protostars in the system are separated by <<200~AU. Here we report observations of dust and molecular gas emission that reveal a disk with spiral structure surrounding the three protostars. Two protostars near the center of the disk are separated by 61 AU, and a tertiary protostar is coincident with a spiral arm in the outer disk at a 183 AU separation. The inferred mass of the central pair of protostellar objects is \sim1 Msun_{sun}, while the disk surrounding the three protostars has a total mass of \sim0.30 M_{\sun}. The tertiary protostar itself has a minimum mass of \sim0.085 Msun_{sun}. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150~AU and 320~AU, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.Comment: Published in Nature on Oct. 27th. 24 pages, 8 figure

    Ras mutation cooperates with β-catenin activation to drive bladder tumourigenesis

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    Mutations in the Ras family of proteins (predominantly in H-Ras) occur in approximately 40% of urothelial cell carcinoma (UCC). However, relatively little is known about subsequent mutations/pathway alterations that allow tumour progression. Indeed, expressing mutant H-Ras within the mouse bladder does not lead to tumour formation, unless this is expressed at high levels. The Wnt signalling pathway is deregulated in approximately 25% of UCC, so we examined if this correlated with the activation of MAPK signalling in human UCC and found a significant correlation. To test the functional significance of this association we examined the impact of combining Ras mutation (H-RasQ61L or K-RasG12D) with an activating β-catenin mutation within the mouse bladder using Cre-LoxP technology. Although alone, neither Ras mutation nor β-catenin activation led to UCC (within 12 months), mice carrying both mutations rapidly developed UCC. Mechanistically this was associated with reduced levels of p21 with dependence on the MAPK signalling pathway. Moreover, tumours from these mice were sensitive to MEK inhibition. Importantly, in human UCC there was a negative correlation between levels of p-ERK and p21 suggesting that p21 accumulation may block tumour progression following Ras mutation. Taken together these data definitively show Ras pathway activation strongly cooperates with Wnt signalling to drive UCC in vivo

    Structural and Spectroscopic Analysis of the Kinase Inhibitor Bosutinib and an Isomer of Bosutinib Binding to the Abl Tyrosine Kinase Domain

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    Chronic myeloid leukemia (CML) is caused by the kinase activity of the BCR-Abl fusion protein. The Abl inhibitors imatinib, nilotinib and dasatinib are currently used to treat CML, but resistance to these inhibitors is a significant clinical problem. The kinase inhibitor bosutinib has shown efficacy in clinical trials for imatinib-resistant CML, but its binding mode is unknown. We present the 2.4 Å structure of bosutinib bound to the kinase domain of Abl, which explains the inhibitor's activity against several imatinib-resistant mutants, and reveals that similar inhibitors that lack a nitrile moiety could be effective against the common T315I mutant. We also report that two distinct chemical compounds are currently being sold under the name “bosutinib”, and report spectroscopic and structural characterizations of both. We show that the fluorescence properties of these compounds allow inhibitor binding to be measured quantitatively, and that the infrared absorption of the nitrile group reveals a different electrostatic environment in the conserved ATP-binding sites of Abl and Src kinases. Exploiting such differences could lead to inhibitors with improved selectivity

    Pleural fluid soluble triggering receptor expressed on myeloid cells-1 as a marker of bacterial infection: a meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Pleural infection is a common clinical problem. Its successful treatment depends on rapid diagnosis and early initiation of antibiotics. The measurement of soluble triggering receptor expressed in myeloid cells-1 (sTREM-1) level in pleural effusions has proven to be a valuable diagnostic tool for differentiating bacterial effusions from effusions of other etiologies. Herein, we performed a meta-analysis to assess the accuracy of pleural fluid sTREM-1 in the diagnosis of bacterial infection.</p> <p>Methods</p> <p>We searched Web of Knowledge and Medline from 1990 through March 2011 for studies reporting diagnostic accuracy data regarding the use of sTREM-1 in the diagnosis of bacterial pleural effusions. Pooled sensitivity and specificity and summary measures of accuracy and Q* were calculated.</p> <p>Results</p> <p>Overall, the sensitivity of sTREM-1was 78% (95% CI: 72%-83%); the specificity was 84% (95% CI: 80%-87%); the positive likelihood ratio was 6.0 (95% CI: 3.3-10.7); and the negative likelihood ratio was 0.22 (95% CI: 0.12-0.40). The area under the SROC curve for sTREM-1 was 0.92. Statistical heterogeneity and inconsistency were found for sensitivity (p = 0.015, χ<sup>2 </sup>= 15.73, I<sup>2 </sup>= 61.9%), specificity (p = 0.000, χ<sup>2 </sup>= 29.90, I<sup>2 </sup>= 79.9%), positive likelihood ratio (p = 0.000, χ<sup>2 </sup>= 33.09, I<sup>2 </sup>= 81.9%), negative likelihood ratio (p = 0.008, χ<sup>2 </sup>= 17.25, I<sup>2 </sup>= 65.2%), and diagnostic odds ratio (p = 0.000, χ<sup>2 </sup>= 28.49, I<sup>2 </sup>= 78.9%). A meta-regression analysis performed showed that the Quality Assessment of Diagnostic Accuracy Studies score (p = 0.3245; RDOR, 4.34; 95% CI, 0.11 to 164.01), the Standards for Reporting of Diagnostic Accuracy score (p = 0.3331; RDOR, 1.70; 95% CI, 0.44 to 6.52), lack of blinding (p = 0.7439; RDOR, 0.60; 95% CI, 0.01 to 33.80), and whether the studies were prospective or retrospective studies (p = 0.2068; RDOR, 7.44; 95% CI, 0.18 to 301.17) did not affect the test accuracy. A funnel plot for publication bias suggested a remarkable trend of publication bias.</p> <p>Conclusions</p> <p>Our findings suggest that sTREM-1 has a good diagnostic accuracy and may provide a useful adjunctive tool for the diagnosis of bacterial pleural effusions. However, further studies are needed in order to identify any differences in the diagnostic performance of sTREM-1 of parapneumonic effusions and empyemas.</p

    Parasite Burden and CD36-Mediated Sequestration Are Determinants of Acute Lung Injury in an Experimental Malaria Model

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    Although acute lung injury (ALI) is a common complication of severe malaria, little is known about the underlying molecular basis of lung dysfunction. Animal models have provided powerful insights into the pathogenesis of severe malaria syndromes such as cerebral malaria (CM); however, no model of malaria-induced lung injury has been definitively established. This study used bronchoalveolar lavage (BAL), histopathology and gene expression analysis to examine the development of ALI in mice infected with Plasmodium berghei ANKA (PbA). BAL fluid of PbA-infected C57BL/6 mice revealed a significant increase in IgM and total protein prior to the development of CM, indicating disruption of the alveolar–capillary membrane barrier—the physiological hallmark of ALI. In contrast to sepsis-induced ALI, BAL fluid cell counts remained constant with no infiltration of neutrophils. Histopathology showed septal inflammation without cellular transmigration into the alveolar spaces. Microarray analysis of lung tissue from PbA-infected mice identified a significant up-regulation of expressed genes associated with the gene ontology categories of defense and immune response. Severity of malaria-induced ALI varied in a panel of inbred mouse strains, and development of ALI correlated with peripheral parasite burden but not CM susceptibility. Cd36−/− mice, which have decreased parasite lung sequestration, were relatively protected from ALI. In summary, parasite burden and CD36-mediated sequestration in the lung are primary determinants of ALI in experimental murine malaria. Furthermore, differential susceptibility of mouse strains to malaria-induced ALI and CM suggests that distinct genetic determinants may regulate susceptibility to these two important causes of malaria-associated morbidity and mortality

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
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