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  • 1
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 147, No. 1 ( 2023-01-03), p. 8-19
    Abstract: The ISCHEMIA trial (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) compared an initial invasive versus an initial conservative management strategy for patients with chronic coronary disease and moderate or severe ischemia, with no major difference in most outcomes during a median of 3.2 years. Extended follow-up for mortality is ongoing. Methods: ISCHEMIA participants were randomized to an initial invasive strategy added to guideline-directed medical therapy or a conservative strategy. Patients with moderate or severe ischemia, ejection fraction ≥35%, and no recent acute coronary syndromes were included. Those with an unacceptable level of angina were excluded. Extended follow-up for vital status is being conducted by sites or through central death index search. Data obtained through December 2021 are included in this interim report. We analyzed all-cause, cardiovascular, and noncardiovascular mortality by randomized strategy, using nonparametric cumulative incidence estimators, Cox regression models, and Bayesian methods. Undetermined deaths were classified as cardiovascular as prespecified in the trial protocol. Results: Baseline characteristics for 5179 original ISCHEMIA trial participants included median age 65 years, 23% women, 16% Hispanic, 4% Black, 42% with diabetes, and median ejection fraction 0.60. A total of 557 deaths accrued during a median follow-up of 5.7 years, with 268 of these added in the extended follow-up phase. This included a total of 343 cardiovascular deaths, 192 noncardiovascular deaths, and 22 unclassified deaths. All-cause mortality was not different between randomized treatment groups (7-year rate, 12.7% in invasive strategy, 13.4% in conservative strategy; adjusted hazard ratio, 1.00 [95% CI, 0.85–1.18]). There was a lower 7-year rate cardiovascular mortality (6.4% versus 8.6%; adjusted hazard ratio, 0.78 [95% CI, 0.63–0.96] ) with an initial invasive strategy but a higher 7-year rate of noncardiovascular mortality (5.6% versus 4.4%; adjusted hazard ratio, 1.44 [95% CI, 1.08–1.91]) compared with the conservative strategy. No heterogeneity of treatment effect was evident in prespecified subgroups, including multivessel coronary disease. Conclusions: There was no difference in all-cause mortality with an initial invasive strategy compared with an initial conservative strategy, but there was lower risk of cardiovascular mortality and higher risk of noncardiovascular mortality with an initial invasive strategy during a median follow-up of 5.7 years. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04894877.
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2023
    detail.hit.zdb_id: 1466401-X
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  • 2
    Online Resource
    Online Resource
    The Company of Biologists ; 2008
    In:  Journal of Cell Science Vol. 121, No. 10 ( 2008-05-15), p. 1577-1586
    In: Journal of Cell Science, The Company of Biologists, Vol. 121, No. 10 ( 2008-05-15), p. 1577-1586
    Abstract: The GTPase Ran has a key role in nuclear import and export, mitotic spindle assembly and nuclear envelope formation. The cycling of Ran between its GTP- and GDP-bound forms is catalyzed by the chromatin-bound guanine nucleotide exchange factor RCC1 and the cytoplasmic Ran GTPase-activating protein RanGAP. The result is an intracellular concentration gradient of RanGTP that equips eukaryotic cells with a `genome-positioning system' (GPS). The binding of RanGTP to nuclear transport receptors (NTRs) of the importin β superfamily mediates the effects of the gradient and generates further downstream gradients, which have been elucidated by fluorescence resonance energy transfer (FRET) imaging and computational modeling. The Ran-dependent GPS spatially directs many functions required for genome segregation by the mitotic spindle during mitosis. Through exportin 1, RanGTP recruits essential centrosome and kinetochore components, whereas the RanGTP-induced release of spindle assembly factors (SAFs) from importins activates SAFs to nucleate, bind and organize nascent spindle microtubules. Although a considerable fraction of cytoplasmic SAFs is active and RanGTP induces only partial further activation near chromatin, bipolar spindle assembly is robustly induced by cooperativity and positive-feedback mechanisms within the network of Ran-activated SAFs. The RanGTP gradient is conserved, although its roles vary among different cell types and species, and much remains to be learned regarding its functions.
    Type of Medium: Online Resource
    ISSN: 1477-9137 , 0021-9533
    Language: English
    Publisher: The Company of Biologists
    Publication Date: 2008
    detail.hit.zdb_id: 219171-4
    detail.hit.zdb_id: 1483099-1
    SSG: 12
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  • 3
    Online Resource
    Online Resource
    American Association for the Advancement of Science (AAAS) ; 2013
    In:  Science Vol. 342, No. 6160 ( 2013-11-15), p. 856-860
    In: Science, American Association for the Advancement of Science (AAAS), Vol. 342, No. 6160 ( 2013-11-15), p. 856-860
    Abstract: Rapid and reductive cell divisions during embryogenesis require that intracellular structures adapt to a wide range of cell sizes. The mitotic spindle presents a central example of this flexibility, scaling with the dimensions of the cell to mediate accurate chromosome segregation. To determine whether spindle size regulation is achieved through a developmental program or is intrinsically specified by cell size or shape, we developed a system to encapsulate cytoplasm from Xenopus eggs and embryos inside cell-like compartments of defined sizes. Spindle size was observed to shrink with decreasing compartment size, similar to what occurs during early embryogenesis, and this scaling trend depended on compartment volume rather than shape. Thus, the amount of cytoplasmic material provides a mechanism for regulating the size of intracellular structures.
    Type of Medium: Online Resource
    ISSN: 0036-8075 , 1095-9203
    RVK:
    RVK:
    Language: English
    Publisher: American Association for the Advancement of Science (AAAS)
    Publication Date: 2013
    detail.hit.zdb_id: 128410-1
    detail.hit.zdb_id: 2066996-3
    detail.hit.zdb_id: 2060783-0
    SSG: 11
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  • 4
    Online Resource
    Online Resource
    Rockefeller University Press ; 2016
    In:  Journal of Cell Biology Vol. 214, No. 2 ( 2016-07-18), p. 133-141
    In: Journal of Cell Biology, Rockefeller University Press, Vol. 214, No. 2 ( 2016-07-18), p. 133-141
    Abstract: Transcription at the centromere of chromosomes plays an important role in kinetochore assembly in many eukaryotes, and noncoding RNAs contribute to activation of the mitotic kinase Aurora B. However, little is known about how mitotic RNA processing contributes to spindle assembly. We found that inhibition of transcription initiation or RNA splicing, but not translation, leads to spindle defects in Xenopus egg extracts. Spliceosome inhibition resulted in the accumulation of high molecular weight centromeric transcripts, concomitant with decreased recruitment of the centromere and kinetochore proteins CENP-A, CENP-C, and NDC80 to mitotic chromosomes. In addition, blocking transcript synthesis or processing during mitosis caused accumulation of MCAK, a microtubule depolymerase, on the spindle, indicating misregulation of Aurora B. These findings suggest that co-transcriptional recruitment of the RNA processing machinery to nascent mitotic transcripts is an important step in kinetochore and spindle assembly and challenge the idea that RNA processing is globally repressed during mitosis.
    Type of Medium: Online Resource
    ISSN: 0021-9525 , 1540-8140
    RVK:
    Language: English
    Publisher: Rockefeller University Press
    Publication Date: 2016
    detail.hit.zdb_id: 1421310-2
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Wiley ; 2012
    In:  Cytoskeleton Vol. 69, No. 3 ( 2012-03), p. 155-165
    In: Cytoskeleton, Wiley, Vol. 69, No. 3 ( 2012-03), p. 155-165
    Abstract: Cytoplasmic linker associated proteins (CLASPs) comprise a class of microtubule (MT) plus end‐binding proteins (+TIPs) that contribute to the dynamics and organization of MTs during many cellular processes, among them mitosis. Human CLASP proteins contain multiple MT‐binding domains, including tumor over‐expressed gene (TOG) domains, and a Ser‐x‐Ile‐Pro (SxIP) motif known to target some +TIPs though interaction with end‐binding protein 1 (EB1). However, how individual domains contribute to CLASP function is poorly understood. We generated full‐length recombinant human CLASP1 and a series of truncation mutants and found that two N‐terminal TOG domains make the strongest contribution to MT polymerization and bundling, but also identified a third TOG domain that further contributes to CLASP activity. Plus end tracking by CLASP requires the SxIP motif and interaction with EB1. The C‐terminal coiled‐coil domain mediates dimerization and association with many other factors, including the kinetochore motor centromere protein E (CENP‐E), and the chromokinesin Xkid. Only the full‐length protein was able to rescue spindle assembly in Xenopus egg extracts depleted of endogenous CLASP. Deletion of the C‐terminal domain caused aberrant MT polymerization and dramatic spindle phenotypes, even with small amounts of added protein, indicating that proper localization of CLASP activity is essential to control MT polymerization during mitosis. © 2012 Wiley Periodicals, Inc
    Type of Medium: Online Resource
    ISSN: 1949-3584 , 1949-3592
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2012
    detail.hit.zdb_id: 2536522-8
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    eLife Sciences Publications, Ltd ; 2023
    In:  eLife Vol. 12 ( 2023-04-25)
    In: eLife, eLife Sciences Publications, Ltd, Vol. 12 ( 2023-04-25)
    Abstract: During the rapid and reductive cleavage divisions of early embryogenesis, subcellular structures such as the nucleus and mitotic spindle scale to decreasing cell size. Mitotic chromosomes also decrease in size during development, presumably to scale coordinately with mitotic spindles, but the underlying mechanisms are unclear. Here we combine in vivo and in vitro approaches using eggs and embryos from the frog Xenopus laevis to show that mitotic chromosome scaling is mechanistically distinct from other forms of subcellular scaling. We found that mitotic chromosomes scale continuously with cell, spindle, and nuclear size in vivo. However, unlike for spindles and nuclei, mitotic chromosome size cannot be reset by cytoplasmic factors from earlier developmental stages. In vitro, increasing nuclear-cytoplasmic (N/C) ratio is sufficient to recapitulate mitotic chromosome scaling, but not nuclear or spindle scaling, through differential loading of maternal factors during interphase. An additional pathway involving importin α scales mitotic chromosomes to cell surface area/volume ratio (SA/V) during metaphase. Finally, single-chromosome immunofluorescence and Hi-C data suggest that mitotic chromosomes shrink during embryogenesis through decreased recruitment of condensin I, resulting in major rearrangements of DNA loop architecture to accommodate the same amount of DNA on a shorter chromosome axis. Together, our findings demonstrate how mitotic chromosome size is set by spatially and temporally distinct developmental cues in the early embryo.
    Type of Medium: Online Resource
    ISSN: 2050-084X
    Language: English
    Publisher: eLife Sciences Publications, Ltd
    Publication Date: 2023
    detail.hit.zdb_id: 2687154-3
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  • 7
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 2009
    In:  BMC Cell Biology Vol. 10, No. 1 ( 2009-12)
    In: BMC Cell Biology, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2009-12)
    Abstract: Muscle fibres are formed by elongation and fusion of myoblasts into myotubes. During this differentiation process, the cytoskeleton is reorganized, and proteins of the centrosome re-localize to the surface of the nucleus. The exact timing of this event, and the underlying molecular mechanisms are still poorly understood. Results We performed studies on mouse myoblast cell lines that were induced to differentiate in culture, to characterize the early events of centrosome protein re-localization. We demonstrate that this re-localization occurs already at the single cell stage, prior to fusion into myotubes. Centrosome proteins that accumulate at the nuclear surface form an insoluble matrix that can be reversibly disassembled if isolated nuclei are exposed to mitotic cytoplasm from Xenopus egg extract. Our microscopy data suggest that this perinuclear matrix of centrosome proteins consists of a system of interconnected fibrils. Conclusion Our data provide new insights into the reorganization of centrosome proteins during muscular differentiation, at the structural and biochemical level. Because we observe that centrosome protein re-localization occurs early during differentiation, we believe that it is of functional importance for the reorganization of the cytoskeleton in the differentiation process.
    Type of Medium: Online Resource
    ISSN: 1471-2121
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2009
    detail.hit.zdb_id: 2964981-X
    detail.hit.zdb_id: 2041486-9
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    Annual Reviews ; 2012
    In:  Annual Review of Cell and Developmental Biology Vol. 28, No. 1 ( 2012-11-10), p. 113-135
    In: Annual Review of Cell and Developmental Biology, Annual Reviews, Vol. 28, No. 1 ( 2012-11-10), p. 113-135
    Abstract: Cell size varies widely among different organisms as well as within the same organism in different tissue types and during development, which places variable metabolic and functional demands on organelles and internal structures. A fundamental question is how essential subcellular components scale to accommodate cell size differences. Nuclear transport has emerged as a conserved means of scaling nuclear size. A meiotic spindle scaling factor has been identified as the microtubule-severing protein katanin, which is differentially regulated by phosphorylation in two different-sized frog species. Anaphase mechanisms and levels of chromatin compaction both act to coordinate cell size with spindle and chromosome dimensions to ensure accurate genome distribution during cell division. Scaling relationships and mechanisms for many membrane-bound compartments remain largely unknown and are complicated by their heterogeneity and dynamic nature. This review summarizes cell and organelle size relationships and the experimental approaches that have elucidated mechanisms of intracellular scaling.
    Type of Medium: Online Resource
    ISSN: 1081-0706 , 1530-8995
    URL: Issue
    RVK:
    Language: English
    Publisher: Annual Reviews
    Publication Date: 2012
    detail.hit.zdb_id: 2982184-8
    detail.hit.zdb_id: 1470447-X
    SSG: 12
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  • 9
    In: Nature, Springer Science and Business Media LLC, Vol. 382, No. 6590 ( 1996-8), p. 420-425
    Type of Medium: Online Resource
    ISSN: 0028-0836 , 1476-4687
    RVK:
    RVK:
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 1996
    detail.hit.zdb_id: 120714-3
    detail.hit.zdb_id: 1413423-8
    SSG: 11
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  • 10
    Online Resource
    Online Resource
    Cold Spring Harbor Laboratory ; 2021
    In:  Genome Research Vol. 31, No. 6 ( 2021-06), p. 958-967
    In: Genome Research, Cold Spring Harbor Laboratory, Vol. 31, No. 6 ( 2021-06), p. 958-967
    Abstract: Centromeres play an essential function in cell division by specifying the site of kinetochore formation on each chromosome for mitotic spindle attachment. Centromeres are defined epigenetically by the histone H3 variant Centromere Protein A (Cenpa). Cenpa nucleosomes maintain the centromere by designating the site for new Cenpa assembly after dilution by replication. Vertebrate centromeres assemble on tandem arrays of repetitive sequences, but the function of repeat DNA in centromere formation has been challenging to dissect due to the difficulty in manipulating centromeres in cells. Xenopus laevis egg extracts assemble centromeres in vitro, providing a system for studying centromeric DNA functions. However, centromeric sequences in Xenopus laevis have not been extensively characterized. In this study, we combine Cenpa ChIP-seq with a k -mer based analysis approach to identify the Xenopus laevis centromere repeat sequences. By in situ hybridization, we show that Xenopus laevis centromeres contain diverse repeat sequences, and we map the centromere position on each Xenopus laevis chromosome using the distribution of centromere-enriched k -mers. Our identification of Xenopus laevis centromere sequences enables previously unapproachable centromere genomic studies. Our approach should be broadly applicable for the analysis of centromere and other repetitive sequences in any organism.
    Type of Medium: Online Resource
    ISSN: 1088-9051 , 1549-5469
    RVK:
    Language: English
    Publisher: Cold Spring Harbor Laboratory
    Publication Date: 2021
    detail.hit.zdb_id: 1483456-X
    SSG: 12
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