23 research outputs found

    Śródoperacyjne rozwarstwienie prawej tętnicy wieńcowej w czasie kaniulacji jej ujścia

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    Right coronary artery dissection related to medical procedures is a very rare life-threatening complication caused by a combination of vessel occlusion and myocardial ischaemia. This paper presents a case of dissection which occurred during a Ross cardiac surgery procedure. The complication was observed after proximal right coronary constriction on the cannula used to administer cardioplegia. The damaged part of the internal membrane was resected during the operation. We present a five-year follow-up of this patient. Kardiol Pol 2011; 69, 9: 966–96

    Identification of essential amino acid residues in the nisin dehydratase NisB

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    Nisin is a posttranslationally-modified antimicrobial peptide that has the ability to induce its own biosynthesis. Serines and threonines in the modifiable core peptide part of precursor nisin are dehydrated to dehydroalanines and dehydrobutyrines by the dehydratase NisB, and subsequently cysteines are coupled to the dehydroamino acids by the cyclase NisC. In this study, we applied extensive site-directed mutagenesis, together with direct binding studies, to investigate the molecular mechanism of the dehydratase NisB. We use a natural nisin-producing strain as a host to probe mutant-NisB functionality. Importantly, we are able to differentiate between intracellular and secreted fully dehydrated precursor nisin, enabling investigation of the NisB properties needed for the release of dehydrated precursor nisin to its devoted secretion system NisT. We report that single amino acid substitutions of conserved residues, i.e. R83A, R83M and R87A result in incomplete dehydration of precursor nisin and prevention of secretion. Single point NisB mutants Y80F and H961A, result in a complete lack of dehydration of precursor nisin, but do not abrogate precursor nisin binding. The data indicate that residues Y80 and H961 are directly involved in catalysis, fitting well with their position in the recently published 3D-structure of NisB. We confirm, by in vivo studies, results that were previously obtained from in vitro experiments and NisB structure elucidation and show that previous findings translate well to effects seen in the original production host

    Fenestration closure with Amplatzer Duct Occluder II in patients after total cavo-pulmonary connection

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    Introduction : Creation of a fenestration during completion of a total cavo-pulmonary connection (TCPC) has been associated with a reduction in early mortality and morbidity. However, the long-term benefits are negated by an associated limitation in exercise tolerance and the potential risks of thrombo-embolic complications. We sought to describe the safety and efficacy of an Amplatzer Duct Occluder II (ADO II) for transcatheter fenestration closure following TCPC. Material and methods : Between January 2000 and July 2014, 102 patients underwent percutaneous closure of extra-cardiac TCPC fenestrations with a range of devices. Patients in whom fenestration closure was performed with an ADO II and who had at least 6 months of follow-up were included in this study. Results : Forty-seven patients had successful fenestration occlusion with an ADO II. The mean oxygen saturation and mean systemic venous pressures increased from 84.8 ±6.1% before to 97.6 ±2.9% (p < 0.001) after and from 14.2 ±2.15 mm Hg before to 15.6 ±2.2 mm Hg after closure (p < 0.001). Eight patients developed heart failure symptoms, managed by optimization of medical therapy, with 1 patient requiring device removal to reopen the fenestration. Color Doppler transthoracic echocardiography demonstrated residual flow across the device in 18 (38%), 10 (22%), 5 (11%) and 4 (9%) patients before discharge, at 1 and 6 months, and at the latest outpatient visit, respectively. Conclusions : The ADO II can be safely and effectively used to close fenestrations in extra-cardiac type Fontan completions. Many of the design features of this device confer potential benefit in this population

    A 10-year single-centre experience in percutaneous interventions for multi-stage treatment of hypoplastic left heart syndrome

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    AbstractObjectivesThe purpose of this paper is to report our 10 years of experience of interventional treatment of patients with hypoplastic left heart syndrome and to focus on the frequency, type, and results of percutaneous interventions during all the stages of palliation, considering the different techniques, devices, and complications.BackgroundConstant progress in surgical treatment of congenital heart defects in the last decade has significantly improved the prognosis for children with hypoplastic left heart syndrome. However, morbidity and mortality remain relatively high. Modern interventional procedures complement or occasionally replace surgical treatment.MethodsBetween January, 2001 and December, 2010, 161 percutaneous interventions were performed in 88 patients with hypoplastic left heart syndrome. Patients were divided into four groups: (a) before the first surgical treatment including hybrid approach, (b) after first-stage Norwood operation, (c) after second-stage bidirectional Glenn operation, and (d) after third-stage Fontan operation.ResultsPercutaneous interventions resulted in statistically significant changes in pulmonary artery pressures, vessel diameters, and O2saturation. Complications occurred in 4.3% of interventions and were related mainly to stent implantation in stenosed pulmonary arteries.ConclusionsPercutaneous interventions may result in haemodynamic stability and reduction in the number of operations. They may result in significant changes in pulmonary artery pressures, vessel diameters, O2saturation, with a low rate of complications, which are mainly related to stent implantation in the pulmonary arteries.</jats:sec

    Production of a Class II Two-Component Lantibiotic of Streptococcus pneumoniae Using the Class I Nisin Synthetic Machinery and Leader Sequence▿

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    Recent studies showed that the nisin modification machinery can successfully dehydrate serines and threonines and introduce lanthionine rings in small peptides that are fused to the nisin leader sequence. This opens up exciting possibilities to produce and engineer larger antimicrobial peptides in vivo. Here we demonstrate the exploitation of the class I nisin production machinery to generate, modify, and secrete biologically active, previously not-yet-isolated and -characterized class II two-component lantibiotics that have no sequence homology to nisin. The nisin synthesis machinery, composed of the modification enzymes NisB and NisC and the transporter NisT, was used to modify and secrete a putative two-component lantibiotic of Streptococcus pneumoniae. This was achieved by genetically fusing the propeptide-encoding sequences of the spr1765 (pneA1) and spr1766 (pneA2) genes to the nisin leader-encoding sequence. The chimeric prepeptides were secreted out of Lactococcus lactis, purified by cation exchange fast protein liquid chromatography, and further characterized. Mass spectrometry analyses demonstrated the presence and partial localization of multiple dehydrated serines and/or threonines and (methyl)lanthionines in both peptides. Moreover, after cleavage of the leader peptide from the prepeptides, both modified propeptides displayed antimicrobial activity against Micrococcus flavus. These results demonstrate that the nisin synthetase machinery can be successfully used to modify and produce otherwise difficult to obtain antimicrobially active lantibiotics
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