Various clinical scenarios leading to development of the string sign of the internal thoracic artery after coronary bypass surgery: the role of competitive flow, a case series

<p>Abstract</p> <p>Background</p> <p>The left internal mammary artery (LIMA) is the choice for grafting of the left anterior descending coronary artery (LAD). One possible mechanism of the rare graft failure involve the presence of competitive flow.</p> <p>Method</p> <p>105 patients who had undergone coronary bypass grafting between 1998 and 2000 were included in this observational study. The recatheterizations were performed 28 months after the operations. The rate of patency the LIMA grafts was determined, and the cases with graft failure were analyzed.</p> <p>Results</p> <p>The LIMA graft was patent in 99 patients (94%). Six patients (6%) exhibited diffuse involution of the graft (string sign). The string sign was always associated with competitive flow as the basis of the LIMA graft involution. In one case quantitative re-evaluation of the preoperative coronary angiography revealed merely less than 50% diameter stenosis on the LAD with a nonligated side-branch of the LIMA. At recatheterization in two patients the pressure wire measurements demonstrated only a non-significant decrease of the fractional flow reserve (0.83 and 0.89), despite the 53% and 57% diameter stenosis in the angiogram. Another patient displayeda significant regression of the LAD lesion between the pre- and postoperative coronary angiography (from 76% to 44%) as the cause of the development of the competitive flow. In one instance, a radial artery graft on the LAD during a redo bypass operation resulted in competitive flow in the radial graft due to the greater diameter than that of the LIMA. In a further patient, competitive flow developed from a short sequential part of the LIMA graft between the nonsignificantly stenosed diagonal branch and the LAD, with involution of the main part of the graft to the diagonal branch.</p> <p>Conclusions</p> <p>The most common cause of the development of the string sign of a LIMA graft due to competitive flow is overassessment of the lesion of the LAD. Regression of a previous lesion or some other neighboring graft can also cause the phenomenon.</p

Decline of FOXN1 gene expression in human thymus correlates with age: possible epigenetic regulation

Submitted by sandra infurna ([email protected]) on 2016-03-15T12:37:15Z No. of bitstreams: 1 wilson2_savino_etal_IOC_2015.pdf: 3767781 bytes, checksum: 43a744d0d5a5f9402ebc023d3834a8ae (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-03-16T13:31:11Z (GMT) No. of bitstreams: 1 wilson2_savino_etal_IOC_2015.pdf: 3767781 bytes, checksum: 43a744d0d5a5f9402ebc023d3834a8ae (MD5)Made available in DSpace on 2016-03-16T13:31:11Z (GMT). No. of bitstreams: 1 wilson2_savino_etal_IOC_2015.pdf: 3767781 bytes, checksum: 43a744d0d5a5f9402ebc023d3834a8ae (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ, Brasil / University of Debrecen. Faculty of Medicine. Department of Human Genetics. Debrecen, Hungary.University of Debrecen. Faculty of Medicine. Department of Biochemistry and Molecular Biology. Debrecen, Hungary.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ, Brasil.Gottsegen György Hungarian Institute of Cardiology. Budapest, Hungary.University of Debrecen. Clinical Center. Department of Cardiac Surgery. Debrecen, Hungary.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ, Brasil.University of Debrecen. Faculty of Medicine. Department of Human Genetics. Debrecen, Hungary / Biosystems International Kft. Debrecen, Hungary.Background: Thymic involution is thought to be an important factor of age related immunodeficiency. Understanding the molecular mechanisms of human thymic senescence may lead to the discovery of novel therapeutic approaches aimed at the reestablishment of central and peripheral T cell repertoire. Results: As an initial approach, here we report that the decline of human thymic FOXN1 transcription correlates with age, while other genes, DLL1, DLL4 and WNT4, essential for thymopoiesis, are constitutively transcribed. Using a human thymic epithelial cell line (hTEC), we show that FOXN1 expression is refractory to signals that induce FOXN1 transcription in primary 3D culture conditions and by stimulation of the canonical WNT signaling pathway. Blockage of FOXN1 induceability in the hTEC line may be mediated by an epigenetic mechanism, the CpG methylation of the FOXN1 gene. Conclusion: We showed a suppression of FOXN1 transcription both in cultured human thymic epithelial cells and in the aging thymus. We hypothesize that the underlying mechanism may be associated with changes of the DNA methylation state of the FOXN1 gene

Additional file 1 of Decline of FOXN1 gene expression in human thymus correlates with age: possible epigenetic regulation

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