959 research outputs found

    Atherectomy of the left main coronary artery with percutaneous cardiopulmonary bypass support

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    Left main (LM) coronary artery stenoses have conventionally been precluded from percutaneous coronary angioplasty because of the prohibitive risk of irreversible hemodynamic collapse after acute closure of the artery, and a relatively high risk of late sudden death.1 When protected by left anterior descending and circumflex coronary artery by-pass grafts, angioplasty of the LM coronary artery can be safely performed but is limited by a rate of recurrent stenosis in excess of 50%.2 Coronary atherectomy has recently been advocated as an alternative procedure because of preliminary data suggesting a lower incidence of acute closure and restenosis after peripheral atherectomy.3 A percutaneous cardiopulmonary support system has also been reported to reduce the hazards of high risk conventional angioplasty including angioplasty of the LM coronary artery.4 We report the successful combined use of percutaneous cardiopulmonary bypass and LM coronary atherectomy in a patient incompletely protected by aortocoronary bypass grafts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27864/1/0000277.pd

    1,5-Bis(2-methyl­phen­yl)-3-nitro­formazan

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    In the title compound, C15H15N5O2, the nitro O atoms are disordered over two sets of sites with an occupancy ratio of 0.75 (4):0.25 (4). Amine–imine tautomerism is observed in the formazan group. This was evident from the similar C—N bond distances in the formazan [1.319 (2) and 1.332 (3) Å], as well as the distribution of the imine proton in the Fourier difference map which refined to a 0.53 (3):0.47 (3) ratio. C—H⋯O and π–π inter­actions [centroid–centroid distances = 3.4813 (1) and 3.3976 (1) Å] are observed in the crystal packing

    (E)-1-[2-(Methyl­sulfan­yl)phen­yl]-2-({(E)-2-[2-(methyl­sulfan­yl)phen­yl]hydrazinyl­idene}(nitro)­meth­yl)diazene

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    In the title compound, C15H15N5O2S2, the phenyl rings make dihedral angles of 4.03 (4) and 9.77 (5)° with the plane defined by the central N—N—C—N—N atoms (r.m.s. deviation = 0.010 Å). The C—S—C—C torsion angles of the methyl­sulfanyl groups with their respective phenyl rings are −7.47 (13) and −72.07 (13)°. The shortest centroid–centroid distance of 3.707 Å occurs between the two π-systems N—N—C—N—N and the benzene ring in the diazene 1-position. The H atom bound to the N atom is involved in intra­molecular N—H⋯N and N—H⋯S contacts, while the nitro O atoms are involved in inter­molecular C—H⋯O contacts

    Loss of a 20S Proteasome Activator in Saccharomyces cerevisiae Downregulates Genes Important for Genomic Integrity, Increases DNA Damage, and Selectively Sensitizes Cells to Agents With Diverse Mechanisms of Action

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    Cytoprotective functions of a 20S proteasome activator were investigated. Saccharomyces cerevisiae Blm10 and human 20S proteasome activator 200 (PA200) are homologs. Comparative genome-wide analyses of untreated diploid cells lacking Blm10 and growing at steady state at defined growth rates revealed downregulation of numerous genes required for accurate chromosome structure, assembly and repair, and upregulation of a specific subset of genes encoding protein-folding chaperones. Blm10 loss or truncation of the Ubp3/Blm3 deubiquitinating enzyme caused massive chromosomal damage and cell death in homozygous diploids after phleomycin treatments, indicating that Blm10 and Ubp3/Blm3 function to stabilize the genome and protect against cell death. Diploids lacking Blm10 also were sensitized to doxorubicin, hydroxyurea, 5-fluorouracil, rapamycin, hydrogen peroxide, methyl methanesulfonate, and calcofluor. Fluorescently tagged Blm10 localized in nuclei, with enhanced fluorescence after DNA replication. After DNA damage that caused a classic G2/M arrest, fluorescence remained diffuse, with evidence of nuclear fragmentation in some cells. Protective functions of Blm10 did not require the carboxyl-terminal region that makes close contact with 20S proteasomes, indicating that protection does not require this contact or the truncated Blm10 can interact with the proteasome apart from this region. Without its carboxyl-terminus, Blm10(−339aa) localized to nuclei in untreated, nonproliferating (G0) cells, but not during G1 S, G2, and M. The results indicate Blm10 functions in protective mechanisms that include the machinery that assures proper assembly of chromosomes. These essential guardian functions have implications for ubiquitin-independent targeting in anticancer therapy. Targeting Blm10/PA200 together with one or more of the upregulated chaperones or a conventional treatment could be efficacious

    Interacting electrons in disordered potentials: Conductance versus persistent currents

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    An expression for the conductance of interacting electrons in the diffusive regime as a function of the ensemble averaged persistent current and the compressibility of the system is presented. This expression involves only ground-state properties of the system. The different dependencies of the conductance and persistent current on the electron-electron interaction strength becomes apparent. The conductance and persistent current of a small system of interacting electrons are calculated numerically and their variation with the strength of the interaction is compared. It is found that while the persistent current is enhanced by interactions, the conductance is suppressed.Comment: REVTeX, 4 pages, 3 figures, all uuencoded, accepted for publication in PR

    Peripheral vascular complications after conventional and complex percutaneous coronary interventional procedures

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    To determine whether complex cardiovascular interventional procedures (including coronary stent implantation, directional atherectomy, aortic valvuloplasty, and the use of an intraaortic balloon pump or cardiopulmonary bypass support) are associated with an increased likelihood of vascular access site complications, 2,400 consecutive cardiac catheterization procedures were prospectively screened over a 12-month study period. Complications occurred in 35 patients after 39 procedures (1.6%) and included the need for vascular surgical repair (17 patients), blood transfusion (28 patients) and systemic antibiotic therapy (7 patients). The incidence of complications after 1,519 diagnostic studies was 0.6%, after 698 conventional coronary balloon angioplasties 2.6%, and after 183 complex interventions 6.0% (p 2 hours' duration and 14% occurred in patients in whom arterial sheaths remained in situ for >24 hours. Detailed demographic and procedural characteristics were compared between the 35 patients with vascular complications and 150 patients randomly drawn from a computerized database of the uncomplicated procedures performed during the screening period. By univariate analysis with correction for multiple comparisons, variables predicting the likelihood of vascular complications included: periprocedural use of heparin (p =8Fr (p =65 years (p = 0.01), and the presence of peripheral vascular disease (p = 0.03).The results of this study suggest that the overall incidence of access site complications is low but increases with the use of complex cardiovascular interventional procedures. Further refinements in the caliber of the new devices, vigilant monitoring of adjunctive anticoagulant therapy, and careful patient selection may reduce the morbidity and increase the safety of these procedures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30283/1/0000685.pd

    Coherent Control of Isotope Separation in HD+ Photodissociation by Strong Fields

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    The photodissociation of the HD+ molecular ion in intense short- pulsed linearly polarized laser fields is studied using a time- dependent wave-packet approach where molecular rotation is fully included. We show that applying a coherent superposition of the fundamental radiation with its second harmonic can lead to asymmetries in the fragment angular distributions, with significant differences between the hydrogen and deuterium distributions in the long wavelength domain where the permanent dipole is most efficient. This effect is used to induce an appreciable isotope separation.Comment: Physical Review Letters, 1995 (in press). 4 pages in revtex format, 3 uuencoded figures. Full postcript version available at: http://chemphys.weizmann.ac.il/~charron/prl.ps or ftp://scipion.ppm.u-psud.fr/coherent.control/prl.p

    The Structure of IR Luminous Galaxies at 100 Microns

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    We have observed twenty two galaxies at 100 microns with the Kuiper Airborne Observatory in order to determine the size of their FIR emitting regions. Most of these galaxies are luminous far-infrared sources, with L_FIR > 10^11 L_sun. This data constitutes the highest spatial resolution ever achieved on luminous galaxies in the far infrared. Our data includes direct measurements of the spatial structure of the sources, in which we look for departures from point source profiles. Additionally, comparison of our small beam 100 micron fluxes with the large beam IRAS fluxes shows how much flux falls beyond our detectors but within the IRAS beam. Several sources with point- like cores show evidence for such a net flux deficit. We clearly resolved six of these galaxies at 100 microns and have some evidence for extension in seven others. Those galaxies which we have resolved can have little of their 100 micron flux directly emitted by a point-like active galactic nucleus (AGN). Dust heated to ~40 K by recent bursts of non-nuclear star formation provides the best explanation for their extreme FIR luminosity. In a few cases, heating of an extended region by a compact central source is also a plausible option. Assuming the FIR emission we see is from dust, we also use the sizes we derive to find the dust temperatures and optical depths at 100 microns which we translate into an effective visual extinction through the galaxy. Our work shows that studies of the far infrared structure of luminous infrared galaxies is clearly within the capabilities of new generation far infrared instrumentation, such as SOFIA and SIRTF.Comment: 8 tables, 23 figure
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