17 research outputs found

    A Strategy To Isolate Modifiers of Caenorhabditis elegans Lethal Mutations: Investigating the Endoderm Specifying Ability of the Intestinal Differentiation GATA Factor ELT-2

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    The ELT-2 GATA factor normally functions in differentiation of the C. elegans endoderm, downstream of endoderm specification. We have previously shown that, if ELT-2 is expressed sufficiently early, it is also able to specify the endoderm and to replace all other members of the core GATA-factor transcriptional cascade (END-1, END-3, ELT-7). However, such rescue requires multiple copies (and presumably overexpression) of the end-1p::elt-2 cDNA transgene; a single copy of the transgene does not rescue. We have made this observation the basis of a genetic screen to search for genetic modifiers that allow a single copy of the end-1p::elt-2 cDNA transgene to rescue the lethality of the end-1 end-3 double mutant. We performed this screen on a strain that has a single copy insertion of the transgene in an end-1 end-3 background. These animals are kept alive by virtue of an extrachromosomal array containing multiple copies of the rescuing transgene; the extrachromosomal array also contains a toxin under heat shock control to counterselect for mutagenized survivors that have been able to lose the rescuing array. A screen of ∼14,000 mutagenized haploid genomes produced 17 independent surviving strains. Whole genome sequencing was performed to identify genes that incurred independent mutations in more than one surviving strain. The C. elegans gene tasp-1 was mutated in four independent strains. tasp-1 encodes the C. elegans homolog of Taspase, a threonine-aspartic acid protease that has been found, in both mammals and insects, to cleave several proteins involved in transcription, in particular MLL1/trithorax and TFIIA. A second gene, pqn-82, was mutated in two independent strains and encodes a glutamine-asparagine rich protein. tasp-1 and pqn-82 were verified as loss-of-function modifiers of the end-1p::elt-2 transgene by RNAi and by CRISPR/Cas9-induced mutations. In both cases, gene loss leads to modest increases in the level of ELT-2 protein in the early endoderm although ELT-2 levels do not strictly correlate with rescue. We suggest that tasp-1 and pqn-82 represent a class of genes acting in the early embryo to modulate levels of critical transcription factors or to modulate the responsiveness of critical target genes. The screen’s design, rescuing lethality with an extrachromosomal transgene followed by counterselection, has a background survival rate of <10−4 without mutagenesis and should be readily adapted to the general problem of identifying suppressors of C. elegans lethal mutations

    Quality of life and patient satisfaction after one-stage implant-based breast reconstruction with an acellular dermal matrix versus two-stage breast reconstruction (BRIOS): primary outcome of a randomised, controlled trial

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    Background There is increasing interest in the use of acellular dermal matrices (ADMs) in implant-based breast reconstruction (IBBR). Suggested advantages are that ADMs facilitate one-stage IBBR and improve aesthetic outcomes. We compared immediate one-stage ADM-assisted IBBR with two-stage IBBR (current standard of care). Our previously reported secondary endpoint showed that one-stage ADM-assisted IBBR was associated with significantly more adverse outcomes. Here, we present the primary endpoint results aiming to assess whether one-stage IBBR with ADM provides higher patient-reported quality of life (QOL) compared with two-stage IBBR. Methods This multicentre, open-label, randomised controlled trial (BRIOS study) was done in eight hospitals in the Netherlands. We recruited women aged older than 18 years with breast carcinoma or a genetic predisposition who intended to undergo skin-sparing mastectomy and immediate IBBR. Participants were randomly assigned to undergo one-stage IBBR with ADM (Strattice, LifeCell, Branchburg, NJ, USA) or two-stage IBBR. Randomisation was stratified by centre and indication for surgery (oncological or prophylactic) in blocks of ten participants. The primary endpoint was patient-reported QOL, as measured with the BREAST-Q (ie, health-related QOL scales and satisfaction scales), in the modified intention-to-treat population. The study follow-up is complete. This study is registered with the Netherlands Trial Register, number NTR5446. Findings Between April 14, 2013, and May 29, 2015, we enrolled 142 women, of whom 69 were randomly assigned to receive one-stage ADM-assisted IBBR and 73 to receive two-stage IBBR. After exclusions, the modified intention-to-treat population comprised 60 patients in the one-stage group and 61 patients in the two-stage group. Of these, 48 women (mean follow-up 17·0 months [SD 7·8]) in the one-stage group and 44 women (17·2 months [SD 6·7]) in the two-stage group completed the BREAST-Q at least 1 year after implant placement. We found no significant differences in postoperative patient-reported QOL domains, including physical wellbeing (one-stage mean 78·0 [SD 14·1] vs two-stage 79·3 [12·2], p=0·60), psychosocial wellbeing (72·6 [17·3] vs 72·8 [19·6], p=0·95), and sexual wellbeing (58·0 [17·0] vs 57·1 [19·5], p=0·82), or in the patient-reported satisfaction domains: satisfaction with breasts (63·4 [15·8] vs 60·3 [15·4], p=0·35) and satisfaction with outcome (72·8 [19·1] vs 67·8 [16·3], p=0·19). Interpretation Taken together with our previously published findings, one-stage IBBR with ADM does not yield superior results in terms of patient-reported QOL compared with two-stage IBBR. Risks for adverse outcomes were significantly higher in the one-stage ADM group. Use of ADM for one-stage IBBM should be considered on a case-by-case basis

    Rethinking Practices and Structures

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    Social theory remains puzzled by the relation between practices and structures, or the link between ‘micro’ and ‘macro’. Grand theorists including Giddens and Bourdieu have gained distinction for their writings on these questions, trying to marry insights and concerns of a ‘micro’ sociological nature with traditional ‘macro’ structural questions including inequality, power relations, and social reproduction. These theorists arguably fail, however, in their attempts to move social theory beyond traditional dualisms. Relevant but neglected contributions from ethnomethodology are introduced and compared to the work of Giddens and Bourdieu in an attempt to identify and outline an approach to practices and structures that more reliably avoids problems of dualism and reification, and at the same time offers an understanding of structures and their relations to practices that can be much more closely grounded in empirical studies

    Б1.В.ДВ.03.02 Физико-химическая механика тампонажных растворов

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    This paper outlines a case for bringing the work of three scholars — Garfinkel (ethnomethodology), Goffman (interaction order/dramaturgy), Sacks (conversation analysis) — into the management and/or organization studies field. It specifically attends to the ways their work adds to understandings of the foundations of organizing. Further, we argue for studies of naturally occurring interaction in ways forged by these scholars and substantiate this move through touching on a number of domains of study where a contribution would be forthcoming, indicated here through the conceptual terrain of practice, identity, power and process theorizing. It is an endeavour which also problematizes the interview `method'. Crucially too, as part of this discussion, we not only summarize elements from these three scholars' legacies for our field, but also introduce the four papers selected for this Symposium Issue. We highlight the ways they take up particular threads and offer empirical illustrations of fine-grained studies of the foundations of organizing
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