Sharpey-Schafer Lecture Gas channels

The traditional dogma has been that all gases diffuse through all membranes simply by dissolving in the lipid phase of the membrane. Although this mechanism may explain how most gases move through most membranes, it is now clear that some membranes have no demonstrable gas permeability, and that at least two families of membrane proteins, the aquaporins (AQPs) and the Rhesus (Rh) proteins, can each serve as pathways for the diffusion of both CO2 and NH3. The knockout of RhCG in the renal collecting duct leads to the predicted consequences in acid–base physiology, providing a clear-cut role for at least one gas channel in the normal physiology of mammals. In our laboratory, we have found that surface-pH (pHS) transients provide a sensitive approach for detecting CO2 and NH3 movement across the cell membranes of Xenopus oocytes. Using this approach, we have found that each tested AQP and Rh protein has its own characteristic CO2/NH3 permeability ratio, which provides the first demonstration of gas selectivity by a channel. Our preliminary AQP1 data suggest that all the NH3 and less than half of the CO2 move along with H2O through the four monomeric aquapores. The majority of CO2 takes an alternative route through AQP1, possibly the central pore at the four-fold axis of symmetry. Preliminary data with two Rh proteins, bacterial AmtB and human erythroid RhAG, suggest a similar story, with all the NH3 moving through the three monomeric NH3 pores and the CO2 taking a separate route, perhaps the central pore at the three-fold axis of symmetry. The movement of different gases via different pathways is likely to underlie the gas selectivity that these channels exhibit

Bioresorbable coronary scaffolds in the treatment of acute myocardial infarction.

Bioresorbable coronary scaffolds (BRS) were developed to overcome limitation of current drug-eluting stents (DES). This thesis gathers clinical and laboratory research regarding BRS implantation in the treatment of acute myocardial infarction.Doctorat en Sciences médicales (Médecine)info:eu-repo/semantics/nonPublishe

Magmaris resorbable magnesium scaffold for the treatment of coronary heart disease: overview of its safety and efficacy

Introduction: Bioresorbable scaffold technology provides transient vessel support with drug-delivery capability without the long-term limitations of the permanent metallic drug-eluting stents (DES). The technology has the potential to overcome many of the safety concerns associated with metallic DES, such as hypersensitivity reactions, late stent thrombosis and progression of atherosclerosis within the stented segment (i.e. neoatherosclerosis). Areas covered: The sirolimus-eluting resorbable magnesium scaffold Magmaris is the only metallic CE-marked resorbable scaffold currently available. This magnesium scaffold is designed for providing a short-term lumen support (up to 3 months) before being completely bioresorbed, eliminating the permanent caging typical of the metallic DES. This review will focus on the device development and characteristics, currently available clinical efficacy and safety data, and potential future perspectives. Expert opinion: The first clinical studies testing this device in a small number of patients have shown promising results with good clinical and safety outcomes up to 3 years' clinical follow-up, supporting the use of Magmaris in simple coronary artery disease.status: Published onlin

Ventricular septal defect: An unusual cause of paradoxical low-gradient aortic stenosis

SCOPUS: no.jinfo:eu-repo/semantics/publishe

Diagnostic Role of Incidental Premature Contractions During Doppler Echocardiography

Cardiac sonographers often perceive premature beats as a limiting factor during echocardiography because they alter filling and contractility, and loops recorded during or after a premature contraction are often discarded. Here we present 2 cases in which the incidental occurrence of premature beats on Doppler echocardiography contributed to the diagnosis. (Level of Difficulty: Intermediate.)SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Dramatic decrease in mitral prosthetic pressure gradient following percutaneous ventricular septal defect closure

SCOPUS: no.jinfo:eu-repo/semantics/publishe

Three-dimensional echocardiography and proximal isovelocity surface area method for the assessment of ventricular septal defect size: Implications for transcatheter closure

SCOPUS: no.jinfo:eu-repo/semantics/publishe

Cardiac calcified amorphous tumor: A systematic review of the literature

Background: Calcified amorphous tumor (CAT) of the heart is a rare non-neoplastic intracavitary cardiac mass. Several case reports have been published but large series are lacking. Objective: To determine clinical features, current management and outcomes of this rare disease. Design: A systematic review of all articles reporting cases of CAT in order to perform a pooled analysis of its clinical features, management and outcomes. Data sources: An electronic search of all English articles using PUBMED was performed. Further studies were identified by cross-referencing from relevant papers. Inclusion criteria: We restricted inclusion to articles reporting cases of CAT in the English language literature published up to July 2014. Data extraction: One author performed data extraction using predefined data fields. Results: A total of 27 articles, reporting 42 cases of CAT were found and included in this review. Conclusion: In this review, the most frequent presenting symptoms were dyspnea and embolic events. Mitral valve and annulus were the most frequent location of CAT. Surgery was most of the time required to confirm diagnosis, and was relatively safe. Overall outcome after surgical resection was good

Swinging cardiac calcified amorphous tumour arising from a calci fied mitral annulus in a patient with normal renal function

A 67-year-old man was referred to our institution for the management of a left-sided intracardiac mass discovered following two cardioembolic events. Imaging studies revealed a highly mobile mass attached to the ventricular side of a calci fied mitral annulus. The mass had not been present on echocardiography 1 year earlier. Surgical resection was performed. Microscopic examination confirmed the diagnosis of a calcified amorphous tumour. The postoperative course was unremarkable, and the patient remains asymptomatic and without recurrence of a mass or neurological event after a 12-month follow-up.SCOPUS: ar.jinfo:eu-repo/semantics/publishe