2,072 research outputs found

    Natural history of gutter-related type Ia endoleaks after snorkel/chimney endovascular aneurysm repair.

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    OBJECTIVE: Alternative endovascular strategies using parallel or snorkel/chimney (chimney endovascular aneurysm repair [ch-EVAR]) techniques have been developed to address the lack of widespread availability and manufacturing limitations with branched/fenestrated aortic devices for the treatment of complex abdominal aortic aneurysms. Despite high technical success and midterm patency of snorkel stent configurations, concerns remain regarding the perceived increased incidence of early gutter-related type Ia endoleaks. We aimed to evaluate the incidence and natural history of gutter-related type Ia endoleaks following ch-EVAR. METHODS: Review of medical records and available imaging studies, including completion angiography and serial computed tomographic angiography, was performed for all patients undergoing ch-EVAR at our institution between September 2009 and January 2015. Only procedures involving ≥1 renal artery with or without visceral snorkel stents were included. Primary outcomes of the study were presence and persistence or resolution of early gutter-related type Ia endoleak. Secondary outcomes included aneurysm sac shrinkage and need for secondary intervention related to the presence of type Ia gutter endoleak. RESULTS: Sixty patients (mean age, 75.8 ± 7.6 years; male, 70.0%) underwent ch-EVAR with a total of 111 snorkel stents (97 renal [33 bilateral renal], 12 superior mesenteric artery, 2 celiac). A mean of 1.9 ± 0.6 snorkel stents were placed per patient. Early gutter-related type Ia endoleaks were noted on 30.0% (n = 18) of initial postoperative imaging studies. Follow-up imaging revealed spontaneous resolution of these gutter endoleaks in 44.3%, 65.2%, and 88.4% of patients at 6, 12, and 18 months postprocedure, respectively. Long-term anticoagulation, degree of oversizing, stent type and diameter, and other clinical/anatomic variables were not significantly associated with presence of gutter endoleaks. Two patients (3.3%) required secondary intervention related to persistent gutter endoleak. At a mean radiologic follow-up of 20.9 months, no difference in mean aneurysm sac size change was observed between those with or without early type Ia gutter endoleak (-6.1 ± 10.0 mm vs -4.9 ± 11.5 mm; P = .23). CONCLUSIONS: Gutter-related type Ia endoleaks represent a relatively frequent early occurrence after ch-EVAR, but appears to resolve spontaneously in the majority of cases during early to midterm follow-up. Given that few ch-EVAR patients require reintervention related to gutter endoleaks and the presence of such endoleak did not correlate to increased risk for aneurysm sac growth, its natural history may be more benign than originally expected

    Iterative in Situ Click Chemistry Assembles a Branched Capture Agent and Allosteric Inhibitor for Akt1

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    We describe the use of iterative in situ click chemistry to design an Akt-specific branched peptide triligand that is a drop-in replacement for monoclonal antibodies in multiple biochemical assays. Each peptide module in the branched structure makes unique contributions to affinity and/or specificity resulting in a 200 nM affinity ligand that efficiently immunoprecipitates Akt from cancer cell lysates and labels Akt in fixed cells. Our use of a small molecule to preinhibit Akt prior to screening resulted in low micromolar inhibitory potency and an allosteric mode of inhibition, which is evidenced through a series of competitive enzyme kinetic assays. To demonstrate the efficiency and selectivity of the protein-templated in situ click reaction, we developed a novel QPCR-based methodology that enabled a quantitative assessment of its yield. These results point to the potential for iterative in situ click chemistry to generate potent, synthetically accessible antibody replacements with novel inhibitory properties

    Structure and Unprecedented Reactivity of a Mononuclear Nonheme Cobalt(III) Iodosylbenzene Complex

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    A mononuclear nonheme cobalt(III) iodosylbenzene complex, [CoIII(TQA)(OIPh)(OH)]2+ (1), is synthesized and characterized structurally and spectroscopically. While 1 is a sluggish oxidant in oxidation reactions, it becomes a competent oxidant in oxygen atom transfer reactions, such as olefin epoxidation, in the presence of a small amount of proton. More interestingly, 1 shows a nucleophilic reactivity in aldehyde deformylation reaction, demonstrating that 1 has an amphoteric reactivity. Another interesting observation is that 1 can be used as an oxygen atom donor in the generation of high-valent metal-oxo complexes. To our knowledge, we present the first crystal structure of a CoIII iodosylbenzene complex and the unprecedented reactivity of metal-iodosylarene adduct

    Differential response to exercise in claudin-low breast cancer

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    Exposure to exercise following a breast cancer diagnosis is associated with reductions in the risk of recurrence. However, it is not known whether breast cancers within the same molecular-intrinsic subtype respond differently to exercise. Syngeneic mouse models of claudin-low breast cancer (i.e., EO771, 4TO7, and C3(1)SV40Tag-p16-luc) were allocated to a uniform endurance exercise treatment dose (forced treadmill exercise) or sham-exercise (stationary treadmill). Compared to sham-controls, endurance exercise treatment differentially affected tumor growth rate: 1- slowed (EO771), 2- accelerated (C3(1)SV40Tag-p16-luc), or 3- was not affected (4TO7). Differential sensitivity of the three tumor lines to exercise was paralleled by effects on intratumoral Ki-67, Hif1-α, and metabolic programming. Inhibition of Hif1-α synthesis by the cardiac glycoside, digoxin, completely abrogated exercise-accelerated tumor growth in C3(1)SV40Tag-p16-luc. These results suggest that intratumoral Hif1-α expression is an important determinant of claudin-low breast cancer adaptation to exercise treatment

    Laboratory-confirmed influenza infection and acute myocardial infarction among United States senior Veterans

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    BackgroundPrevious studies established an association between laboratory-confirmed influenza infection (LCI) and hospitalization for acute myocardial infarction (AMI) but not causality. We aimed to explore the underlying mechanisms by adding biological mediators to an established study design used by earlier studies.MethodsWith data on biomarkers, we used a self-controlled case-series design to evaluate the effect of LCI on hospitalization for AMI among Veterans Health Administration (VHA) patients. We included senior Veterans (age 65 years and older) with LCI between 2010 through 2015. Patient-level data from VHA electronic medical records were used to capture laboratory results, hospitalizations, and baseline patient characteristics. We defined the "risk interval" as the first 7 days after specimen collection and the "control interval" as 1 year before and 1 year after the risk interval. More importantly, using mediation analysis, we examined the role of abnormal white blood cell (WBC) and platelet count in the relationship between LCI and AMI to explore the thrombogenic nature of this association, thus potential causality.ResultsWe identified 391 hospitalizations for AMI that occurred within +/-1 year of a positive influenza test, of which 31 (31.1 admissions/week) occurred during the risk interval and 360 (3.5/per week) during the control interval, resulting in an incidence ratio (IR) for AMI admission of 8.89 (95% confidence interval [CI]: 6.16-12.84). In stratified analyses, AMI risk was significantly elevated among patients with high WBC count (IR, 12.43; 95% CI: 6.99-22.10) and high platelet count (IR, 15.89; 95% CI: 3.59-70.41).ConclusionWe confirmed a significant association between LCI and AMI. The risk was elevated among those with high WBC or platelet count, suggesting a potential role for inflammation and platelet activation in the underlying mechanism

    The Antiferromagnetic Band Structure of La2CuO4 Revisited

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    Using the Becke-3-LYP functional, we have performed band structure calculations on the high temperature superconductor parent compound, La2CuO4. Under the restricted spin formalism (rho(alpha) equal to rho(beta)), the R-B3LYP band structure agrees well with the standard LDA band structure. It is metallic with a single Cu x2-y2/O p(sigma) band crossing the Fermi level. Under the unrestricted spin formalism (rho(alpha) not equal to rho(beta)), the UB3LYP band structure has a spin polarized antiferromagnetic solution with a band gap of 2.0 eV, agreeing well with experiment. This state is 1.0 eV (per formula unit) lower than that calculated from the R-B3LYP. The apparent high energy of the spin restricted state is attributed to an overestimate of on-site Coulomb repulsion which is corrected in the unrestricted spin calculations. The stabilization of the total energy with spin polarization arises primarily from the stabilization of the x2-y2 band, such that the character of the eigenstates at the top of the valence band in the antiferromagnetic state becomes a strong mixture of Cu x2-y2/O p(sigma) and Cu z2/O' p(z). Since the Hohenberg-Kohn theorem requires the spin restricted and spin unrestricted calculations give exactly the same ground state energy and total density for the exact functionals, this large disparity in energy reflects the inadequacy of current functionals for describing the cuprates. This calls into question the use of band structures based on current restricted spin density functionals (including LDA) as a basis for single band theories of superconductivity in these materials.Comment: 13 pages, 8 figures, to appear in Phys. Rev. B, for more information see http://www.firstprinciples.co

    Influenza vaccine in chronic obstructive pulmonary disease among elderly male veterans

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    BACKGROUND: Prior studies have established those elderly patients with chronic obstructive pulmonary disease (COPD) are at elevated risk for developing influenza-associated complications such as hospitalization, intensive-care admission, and death. This study sought to determine whether influenza vaccination could improve survival among elderly patients with COPD. MATERIALS/METHODS: This study included Veterans (age ≥ 65 years) diagnosed with COPD that received care at the United States Veterans Health Administration (VHA) during four influenza seasons, from 2012–2013 to 2015–2016. We linked VHA electronic medical records and Medicare administrative files to Centers for Disease Control and Prevention National Death Index cause of death records as well as influenza surveillance data. A multivariable time-dependent Cox proportional hazards model was used to compare rates of mortality of recipients of influenza vaccination to those who did not have records of influenza vaccination. We estimated hazard ratios (HRs) adjusted for age, gender, race, socioeconomic status, comorbidities, and healthcare utilization. RESULTS: Over a span of four influenza seasons, we included 1,856,970 person-seasons of observation where 1,199,275 (65%) had a record of influenza vaccination and 657,695 (35%) did not have a record of influenza vaccination. After adjusting for comorbidities, demographic and socioeconomic characteristics, influenza vaccination was associated with reduced risk of death during the most severe periods of influenza seasons: 75% all-cause (HR = 0.25; 95% CI: 0.24–0.26), 76% respiratory causes (HR = 0.24; 95% CI: 0.21–0.26), and 82% pneumonia/influenza cause (HR = 0.18; 95% CI: 0.13–0.26). A significant part of the effect could be attributed to “healthy vaccinee” bias as reduced risk of mortality was also found during the periods when there was no influenza activity and before patients received vaccination: 30% all-cause (HR = 0.70; 95% CI: 0.65–0.75), 32% respiratory causes (HR = 0.68; 95% CI: 0.60–0.78), and 51% pneumonia/influenza cause (HR = 0.49; 95% CI: 0.31–0.78). However, as a falsification study, we found that influenza vaccination had no impact on hospitalization due to urinary tract infection (HR = 0.97; 95% CI: 0.80–1.18). CONCLUSIONS: Among elderly patients with COPD, influenza vaccination was associated with reduced risk for all-cause and cause-specific mortality
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