Adult cardiac myocytes survive and remain excitable during long-term culture on synthetic supports

AbstractObjective: Cardiomyocytes can be transplanted successfully into skeletal and cardiac muscle. Our goal was to determine the feasibility of grafting cardiomyocytes onto various synthetic supports to create an excitable and viable tissue for implantation. Methods: Adult rat cardiomyocytes were cultured over an 8-week period onto different substitutes, including human glutaraldehyde-treated pericardium (n = 3), equine glutaraldehyde-treated pericardium (n = 3), polytetrafluoroethylene (n = 8), Dacron polyester (n = 16), and Vicryl polyglactin (n = 8). Results: Only the cells seeded on the Dacron survived, with the synthetic fibers colonized at 8 weeks. On the other supports, the number of myocytes progressively decreased from the first week, with their density (number of cells per square millimeter) being, after 20 days, 17 ± 2 on the polytetrafluoroethylene and 5 ± 1 on the human or equine pericardium compared with 45 ± 3 on the Dacron. After 8 weeks of culture on Dacron, the sarcomeric protein (sarcomeric α-actinin) was detected in all cells. In addition, the staining was regularly arranged and well aligned in a striated pattern. Spontaneous beating activity was obtained. Moreover, electrical stimulation of the cell preparation resulted in the generation of calcium transients, the frequency of which followed the frequency of the electrical stimulation. Conclusions: These results suggest that adult cardiac myocytes remain viable and excitable during long-term culture on a 3-dimensional Dacron support, which might constitute a new synthetic cardiac tissue. (J Thorac Cardiovasc Surg 2001;121:510-9

Experimental Studies of solubility of Elemental Sulphur in Supercritical Nitrogen

International audienc

Clone, un jeu de simulation pour la formation à l’organisation des soins infirmiers

TIC : technologies de l’Information et de la CommunicationInternational audienc

Le corps et l'interaction soignant-soigné (le travail émotionnel des soignants à l'hôpital)

TOULOUSE2-BUC Mirail (315552102) / SudocSudocFranceF

Sociologie, anthropologie et soins: Formations aux métiers du soin et de la santé : études de textes, pour un regard différent sur les pratiques

International audienceÀ travers des extraits de textes de sociologie et d'anthropologie concernant le soin et des questionnements liant théorie et pratique, ce livre vise à faire adopter un point de vue différent sur les situations et à rendre les pratiques plus humaines.Inscrits dans des cadres sociaux très variés, les personnes soignées et les soignants vivent une expérience de la maladie, de la santé et des soins qui peut prendre de multiples sens, avec des conséquences éventuellement contradictoires. Chacun étant pris dans des systèmes organisationnels et dans des ordres d'interaction, les logiques professionnelles peuvent se confronter aux logiques profanes.Face à ce contexte toujours plus prégnant dans le domaine de la santé, ce livre se propose de contribuer à développer chez les étudiants des formations paramédicales et médicales un regard sociologique et anthropologique sur les situations professionnelles qu'ils vont rencontrer au cours de leurs stages et tout au long de leur vie professionnelle. Élaboré dans un travail conjoint de sociologues et de professionnels de la formation aux métiers de la santé, il est construit de manière à permettre une articulation entre théorie et pratique. Les auteurs ont sélectionné des extraits de textes issus des champs de la sociologie et de l'anthropologie, afin de donner aux futurs professionnels un aperçu des possibilités offertes par ces disciplines d'adopter un regard différent sur les situations vécues au quotidien.Il s'agit ainsi de contribuer à développer une culture sociologique et anthropologique chez les étudiants, qui seront guidés par les formateurs pour approfondir les questionnements qui accompagnent chaque texte de même que pour utiliser ces grilles de lecture dans leurs analyses de situation et leurs prises de décision

Characterisation of Reference Materials for In situ Rb-Sr Dating by LA-ICP-MS/MS

International audienceWe present here Rb and Sr mass fractions and 87 Sr/ 86 Sr compositions for four reference materials (RM) obtained from the Service d'Analyse des Roches et des Minéraux (SARM) in Nancy, France: Mica-Mg, Mica-Fe, GL-O and FK-N. These four RMs have different chemical compositions spanning the range of those of most K-bearing feldspars and micas, making them potential calibration materials for in situ Rb-Sr dating of natural minerals by LA-ICP-MS/MS. Selected grains and flakes from the four RMs present variable degrees of heterogeneity observable by SEM-EDS and EPMA imaging and chemical mapping. This heterogeneity is mainly related to inclusions of minerals within flakes and grains and to chemical substitutions linked to crystallographic control and alteration processes. The Mica-Mg RM is the least affected. The powders available at the SARM were analysed by ID-TIMS (87 Sr/ 86 Sr and Sr mass fractions) and ID-MC-ICP-MS (Rb) after digestion and separation. The mean 87 Rb/ 86 Sr ratios are 155.6 ± 4.7% (2s, as for other RMs) for Mica-Mg, 1815 ± 14% for Mica-Fe, 36.2 ± 11% for GL-O and 69.9 ± 5.9% for FK-N. The mean 87 Sr/ 86 Sr ratios are 1.8622 ± 0.36% (2s, as for other RMs) for Mica-Mg, 7.99 ± 13% for Mica-Fe, 0.75305 ± 0.12% for GL-O, and 1.2114 ± 0.17% for FK-N. The four RMs each show dispersion in 87 Sr/ 86 Sr and Rb and Sr mass fractions, to degrees that differ between RMs and that reflect the heterogeneity of their original crystals. The most heterogeneous RMs are GL-O and Mica-Fe. The calculated mean Rb-Sr isotopic ages are 521 ± 24 Ma for Mica-Mg, 287 ± 55 Ma for Mica-Fe, 89.2 ± 9.9 Ma for GL-O and 512 ± 30 Ma for FK-N. The proposed age for Mica-Fe may be unreliable due to the elevated dispersion of individual analysis linked to the highly radiogenic composition of the biotite and to the presence of numerous mineral inclusions. We recommend use of these proposed working values of 87 Sr/ 86 Sr and 87 Rb/ 86 Sr ratios and associated uncertainties when using the four RMs for in situ Rb-Sr dating by LA-ICP-MS/MS. The availability of these four well-characterised RM will allow progress in the development and application of the Rb-Sr dating approach by LA-ICP-MS/MS

Evaluation of rammelsbergite (NiAs2) as a novel mineral for 187Re-187Os dating and implications for unconformity-related U deposits

International audienceRammelsbergite (NiAs 2) is often present in ore deposits worldwide in association with other arsenides, sulphides and sulfarsenides. This work demonstrates the value of the application of the Re-Os isotopic system to the dating of rammelsbergite. Using the example of the Cigar Lake uranium deposit (Athabasca Basin, Saskatchewan, Canada), our results show that rammelsbergite concentrates significant and variable amounts of Re when crystallizing, up to 1.6 mg g À1 , while incorporating minimal common Os. Such characteristics make this mineral an ideal target for Re-Os isotopic dating, by both isochron and model age methods. Remarkable agreement of the Re-Os age of the rammelsbergite with the U-Pb age of the uranium oxide grains found inside one of the massive rammelsbergite veins confirms the applicability of the method. The selected rammelsbergite samples from the Cigar Lake uranium deposit yield a 187 Re-187 Os isochron age of 1239 +33/À20 Ma. These results challenge a long-standing petrogenetic model which postulates contemporaneous U oxide and Ni-Co-arsenide deposition in unconformity-related uranium deposits. The new Re-Os age of rammelsbergite veins indicates that arsenide crystallization postdated the deposition of the primary uranium oxides at 1461-1341 Ma, implying that uranium oxides and nickel arsenides, as well as other sulphides and sulfarsenides, were not precipitated contemporaneously during a single hydrothermal event as previously proposed. The 187 Re-187 Os data suggest that crystallization of rammelsbergite and co-genetic sulphides, arsenides and sulfarsenides was linked to the ca. 1270 Ma Mackenzie magmatic event, marked by the emplacement of mafic dikes throughout the Canadian Shield, including in the area of the Athabasca Basin. This study therefore suggests a new hypothesis for the origin of nickel, cobalt, sulfur and arsenic in unconformity-related U deposits of the Athabasca Basin. More broadly, the successful application of the 187 Re-187 Os rammelsbergite chronometer in this geological context suggests that its applic

Myocardial cell death in fibrillating and dilated human right atria

AbstractOBJECTIVESThe aim of the present study was to determine if myocytes can die by apoptosis in fibrillating and dilated human atria.BACKGROUNDThe cellular remodeling that occurs during atrial fibrillation (AF) may reflect a degree of dedifferentiation of the atrial myocardium, a process that may be reversible.METHODSWe examined human right atrial myocardium specimens (n = 50) for the presence of apoptotic myocytes. We used immunohistochemical and Western blotting analysis to examine the expression of a final effector of programmed cell death, caspase-3 (CASP-3) and of regulatory proteins from the BCL-2 family.RESULTSSections from atria in AF contained a high percentage of large myocytes with a disrupted sarcomeric apparatus replaced by glycogen granules (64.4 ± 6.3% vs. 12.2 ± 5.8%). These abnormal myocytes, which also predominated in atria from hearts with decreased left ventricular ejection fraction (42.3 ± 10.1%), contained large nuclei, most of which were TUNEL positive, indicating a degree of DNA breakage. None of these abnormal myocytes expressed the proliferative antigen Ki-67. A small percentage of the enlarged nuclei (4.2 ± 0.8%) contained condensed chromatin and were strongly TUNEL positive. Both the pro- and activated forms of CASP-3 were detected in diseased myocardial samples, which also showed stronger CASP-3 expression than controls. Expression of the antiapoptotic BCL-2 protein was decreased in diseased atria, whereas that of the proapoptotic BAX protein remained unchanged.CONCLUSIONSIn fibrillating and dilated atria, apoptotic death of myocytes with myolysis contributes to cellular remodeling, which may not be entirely reversible