220 research outputs found

    Reversal of aging-induced increases in aortic stiffness by targeting cytoskeletal protein-protein interfaces

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    BACKGROUND: The proximal aorta normally functions as a critical shock absorber that protects small downstream vessels from damage by pressure and flow pulsatility generated by the heart during systole. This shock absorber function is impaired with age because of aortic stiffening. METHODS AND RESULTS: We examined the contribution of common genetic variation to aortic stiffness in humans by interrogating results from the AortaGen Consortium genome‐wide association study of carotid‐femoral pulse wave velocity. Common genetic variation in the N‐WASP (WASL) locus is associated with carotid‐femoral pulse wave velocity (rs600420, P=0.0051). Thus, we tested the hypothesis that decoy proteins designed to disrupt the interaction of cytoskeletal proteins such as N‐WASP with its binding partners in the vascular smooth muscle cytoskeleton could decrease ex vivo stiffness of aortas from a mouse model of aging. A synthetic decoy peptide construct of N‐WASP significantly reduced activated stiffness in ex vivo aortas of aged mice. Two other cytoskeletal constructs targeted to VASP and talin‐vinculin interfaces similarly decreased aging‐induced ex vivo active stiffness by on‐target specific actions. Furthermore, packaging these decoy peptides into microbubbles enables the peptides to be ultrasound‐targeted to the wall of the proximal aorta to attenuate ex vivo active stiffness. CONCLUSIONS: We conclude that decoy peptides targeted to vascular smooth muscle cytoskeletal protein‐protein interfaces and microbubble packaged can decrease aortic stiffness ex vivo. Our results provide proof of concept at the ex vivo level that decoy peptides targeted to cytoskeletal protein‐protein interfaces may lead to substantive dynamic modulation of aortic stiffness.Published versio

    Genome-Wide Identification of Ampicillin Resistance Determinants in Enterococcus faecium

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    Enterococcus faecium has become a nosocomial pathogen of major importance, causing infections that are difficult to treat owing to its multi-drug resistance. In particular, resistance to the ÎČ-lactam antibiotic ampicillin has become ubiquitous among clinical isolates. Mutations in the low-affinity penicillin binding protein PBP5 have previously been shown to be important for ampicillin resistance in E. faecium, but the existence of additional resistance determinants has been suggested. Here, we constructed a high-density transposon mutant library in E. faecium and developed a transposon mutant tracking approach termed Microarray-based Transposon Mapping (M-TraM), leading to the identification of a compendium of E. faecium genes that contribute to ampicillin resistance. These genes are part of the core genome of E. faecium, indicating a high potential for E. faecium to evolve towards ÎČ-lactam resistance. To validate the M-TraM results, we adapted a Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. We confirmed the role of four genes in ampicillin resistance by the generation of targeted mutants and further characterized these mutants regarding their resistance to lysozyme. The results revealed that ddcP, a gene predicted to encode a low-molecular-weight penicillin binding protein with D-alanyl-D-alanine carboxypeptidase activity, was essential for high-level ampicillin resistance. Furthermore, deletion of ddcP sensitized E. faecium to lysozyme and abolished membrane-associated D,D-carboxypeptidase activity. This study has led to the development of a broadly applicable platform for functional genomic-based studies in E. faecium, and it provides a new perspective on the genetic basis of ampicillin resistance in this organism

    Dynamics of ampicillin-resistant Enterococcus faecium clones colonizing hospitalized patients: data from a prospective observational study

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    <p>Abstract</p> <p>Background</p> <p>Little is known about the dynamics of colonizing <it>Enterococcus faecium </it>clones during hospitalization, invasive infection and after discharge.</p> <p>Methods</p> <p>In a prospective observational study we compared intestinal <it>E. faecium </it>colonization in three patient cohorts: 1) Patients from the Hematology Unit at the University Hospital Basel (UHBS), Switzerland, were investigated by weekly rectal swabs (RS) during hospitalization (group 1a, n = 33) and monthly after discharge (group 1b, n = 21). 2) Patients from the Intensive Care Unit (ICU) at the University Medical Center Utrecht, the Netherlands (group 2, n = 25) were swabbed weekly. 3) Patients with invasive <it>E. faecium </it>infection at UHBS were swabbed at the time of infection (group 3, n = 22). From each RS five colonies with typical <it>E</it>. <it>faecium </it>morphology were picked. Species identification was confirmed by PCR and ampicillin-resistant <it>E. faecium </it>(ARE) isolates were typed using Multiple Locus Variable Number Tandem Repeat Analysis (MLVA). The Simpson's Index of Diversity (SID) was calculated.</p> <p>Results</p> <p>Out of 558 ARE isolates from 354 RS, MT159 was the most prevalent clone (54%, 100%, 52% and 83% of ARE in groups 1a, 1b, 2 and 3, respectively). Among hematological inpatients 13 (40%) had ARE. During hospitalization, the SID of MLVA-typed ARE decreased from 0.745 [95%CI 0.657-0.833] in week 1 to 0.513 [95%CI 0.388-0.637] in week 3. After discharge the only detected ARE was MT159 in 3 patients. In the ICU (group 2) almost all patients (84%) were colonized with ARE. The SID increased significantly from 0.373 [95%CI 0.175-0.572] at week 1 to a maximum of 0.808 [95%CI 0.768-0.849] at week 3 due to acquisition of multiple ARE clones. All 16 patients with invasive ARE were colonized with the same MLVA clone (<it>p </it>< 0.001).</p> <p>Conclusions</p> <p>In hospitalized high-risk patients MT159 is the most frequent colonizer and cause of invasive <it>E. faecium </it>infections. During hospitalization, ASE are quickly replaced by ARE. Diversity of ARE increases on units with possible cross-transmission such as ICUs. After hospitalization ARE are lost with the exception of MT159. In invasive infections, the invasive clone is the predominant gut colonizer.</p

    Interleukin-6 Receptor Antagonists in Critically Ill Patients with Covid-19.

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    BACKGROUND: The efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear. METHODS: We evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours after starting organ support in the intensive care unit (ICU), were randomly assigned to receive tocilizumab (8 mg per kilogram of body weight), sarilumab (400 mg), or standard care (control). The primary outcome was respiratory and cardiovascular organ support-free days, on an ordinal scale combining in-hospital death (assigned a value of -1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with predefined criteria for superiority, efficacy, equivalence, or futility. An odds ratio greater than 1 represented improved survival, more organ support-free days, or both. RESULTS: Both tocilizumab and sarilumab met the predefined criteria for efficacy. At that time, 353 patients had been assigned to tocilizumab, 48 to sarilumab, and 402 to control. The median number of organ support-free days was 10 (interquartile range, -1 to 16) in the tocilizumab group, 11 (interquartile range, 0 to 16) in the sarilumab group, and 0 (interquartile range, -1 to 15) in the control group. The median adjusted cumulative odds ratios were 1.64 (95% credible interval, 1.25 to 2.14) for tocilizumab and 1.76 (95% credible interval, 1.17 to 2.91) for sarilumab as compared with control, yielding posterior probabilities of superiority to control of more than 99.9% and of 99.5%, respectively. An analysis of 90-day survival showed improved survival in the pooled interleukin-6 receptor antagonist groups, yielding a hazard ratio for the comparison with the control group of 1.61 (95% credible interval, 1.25 to 2.08) and a posterior probability of superiority of more than 99.9%. All secondary analyses supported efficacy of these interleukin-6 receptor antagonists. CONCLUSIONS: In critically ill patients with Covid-19 receiving organ support in ICUs, treatment with the interleukin-6 receptor antagonists tocilizumab and sarilumab improved outcomes, including survival. (REMAP-CAP ClinicalTrials.gov number, NCT02735707.)

    Human OTULIN haploinsufficiency impairs cell-intrinsic immunity to staphylococcal alpha-toxin

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    The molecular basis of interindividual clinical variability upon infection with Staphylococcus aureus is unclear. We describe patients with haploinsufficiency for the linear deubiquitinase OTULIN, encoded by a gene on chromosome 5p. Patients suffer from episodes of life-threatening necrosis, typically triggered by S. aureus infection. The disorder is phenocopied in patients with the 5p- (Cri-du-Chat) chromosomal deletion syndrome. OTULIN haploinsufficiency causes an accumulation of linear ubiquitin in dermal fibroblasts, but tumor necrosis factor receptor-mediated nuclear factor kappa B signaling remains intact. Blood leukocyte subsets are unaffected. The OTULIN-dependent accumulation of caveolin-1 in dermal fibroblasts, but not leukocytes, facilitates the cytotoxic damage inflicted by the staphylococcal virulence factor alpha-toxin. Naturally elicited antibodies against alpha-toxin contribute to incomplete clinical penetrance. Human OTULIN haploinsufficiency underlies life-threatening staphylococcal disease by disrupting cell-intrinsic immunity to alpha-toxin in nonleukocytic cells.Peer reviewe

    Directing Modernist Spirituality: Evelyn Underhill, the Subliminal Consciousness and Spiritual Direction

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    Outlining an alternative trajectory for modernist spirituality to that traced in Pericles Lewis’s 'Religious Experience and the Modernist Novel' (2010), I argue that modernist religious thought, far from playing heir to the long march of secularization, was in fact conditioned by a late-nineteenth-century cultural crisis that issued in a range of religious experiments and renewals, one of which was Evelyn Underhill’s 'Mysticism: A Study in the Nature and Development of Man’s Spiritual Consciousness' (1911), a text that not only brought together mystical traditions and scientific discoveries, but also used this interdisciplinary remit to counter existing secularizing perspectives. An important dimension of Underhill’s work was its collaborative nature; it offers, I argue, not access to rarefied enlightenment, but rather a bold attempt to navigate a treacherous religious landscape

    Journalism, public imagination and cultural policy

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    Although the phrase 'cultural policy' would rarely form on journalists' lips, the cultural results of journalism permeate national imaginations in the totality of their impressions, through processes of persuasion set-up within an apparent framework of choice. Problematic cultural effects are produced through the mechanisms of gigantic markets whose very randomness seduces observers into believing that they are protected from conspiracy and manipulation. The paper explores certain mystifications within the ethos of mass market journalism, whose professional techniques beguile both producers and public in the way they suppress criticism or sympathy, and eradicate all but populist positions. The paper contends that many journalists are fuelled by an ethos of puritanical anti-intellectualism. These themes are pursued by deconstructing some of the 'professional' codes in journalism and its didactic literature, in order to expose a mechanism for channelling public mentality that is condoned through the anti-intellectualism of its techniques. The paper analyses media texts and processes of journalistic enculturation, engaging broadly with discourses inspired by the Frankfurt School and ideas of hegemony refined by Gramsci

    Economic imaginaries of the Anti-biosis : between ‘economies of resistance’ and the ‘resistance of economies’

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    This paper seeks reports on the way economic principles, formulae and discourse inform biological research on antimicrobial resistance (AMR) in the life sciences. AMR, it can be argued, has become the basis for performing certain forms of ‘economic imaginary’. Economic imaginaries are ways of projecting and materially restructuring economic and political orders through motifs, metaphors, images and practices. The paper contributes to critical social science and humanities research on the socio-economic underpinning of biological discourse. The performance of economy in this context can be seen to follow two key trajectories. The first trajectory, discussed at length in this paper, might be described as ‘economies of resistance’. Here the language of market economics structures and frames microbiological explanations of bacterial resistance. This can be illustrated through, for example, biological theories of ‘genetic capitalism’ where capitalism itself is seen to furnish microbial life with modes of economic behaviour and conduct. ‘Economies of resistance’ are evidence of the naturalisation of socio-economic structures in expert understandings of AMR. The methodological basis of this paper lies in a historical genealogical investigation into the use of economic and market principles in contemporary microbiology. The paper reports on a corpus of published academic sources identified through the use of keywords, terms, expressions and metaphors linked to market economics. Search terms included, but were not limited to: ‘trade-off’, ‘investment’, ‘market/s’, ‘investment’, ‘competition’, ‘cooperation’, ‘economy’, ‘capital/ism’, ‘socialist/ism’, etc. ‘Economies of resistance’ complements a second distinct trajectory that can be seen to flow in the opposite direction from biology to economic politics (the ‘resistance of economies’). Here, economic imaginaries of microbial life are redeployed in large-scale debates about the nature of economic life, about the future of the welfare state, industrial strategy, and about the politics of migration and race, etc. ‘Economies of resistance’ and the ‘resistance of economies’ are not unrelated but, instead, they are mutually constituting dynamics in the co-production of AMR. In attempting to better understand this co-production, the paper draws upon literatures on the biopolitics of immunity in political philosophy and Science and Technology Studies (STS)
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