Ephrin-B1 regulates the adult diastolic function through a late postnatal maturation of cardiomyocyte surface crests.

The rod-shaped adult cardiomyocyte (CM) harbors a unique architecture of its lateral surface with periodic crests, relying on the presence of subsarcolemmal mitochondria (SSM) with unknown role. Here, we investigated the development and functional role of CM crests during the postnatal period. We found in rodents that CM crest maturation occurs late between postnatal day 20 (P20) and P60 through both SSM biogenesis, swelling and crest-crest lateral interactions between adjacent CM, promoting tissue compaction.

Structural evidence for a new elaborate 3D-organization of the cardiomyocyte lateral membrane in adult mammalian cardiac tissues.

Aims: This study explored the lateral crest structures of adult cardiomyocytes (CMs) within healthy and diseased cardiac tissue.

Methods And Results: Using high-resolution electron and atomic force microscopy, we performed an exhaustive quantitative analysis of the three-dimensional (3D) structure of the CM lateral surface in different cardiac compartments from various mammalian species (mouse, rat, cow, and human) and determined the technical pitfalls that limit its observation. Although crests were observed in nearly all CMs from all heart compartments in all species, we showed that their heights, dictated by the subsarcolemmal mitochondria number, substantially differ between compartments from one species to another and tightly correlate with the sarcomere length.

Biophysical properties of cardiomyocyte surface explored by multiparametric AFM.

PeakForce Quantitative Nanomechanical Mapping (PeakForce QNM) multiparametric AFM mode was adapted to qualitative and quantitative study of the lateral membrane of cardiomyocytes (CMs), extending this powerful mode to the study of soft cells. On living CM, PeakForce QNM depicted the crests and hollows periodic alternation of cell surface architecture previously described using AFM Force Volume (FV) mode. PeakForce QNM analysis provided better resolution in terms of pixel number compared to FV mode and reduced acquisition time, thus limiting the consequences of spontaneous living adult CM dedifferentiation once isolated from the cardiac tissue.

[Liver transplantation, vascular complications, role of imaging, percutaneous therapeutic possibilities].

Duplex Doppler ultrasound should be the first investigation when a vascular complication is suspected. Serial examinations may increase sensitivity. Color imaging enhances identification of small vessels and increases specificity.

[Use of a constant-flow 2-phase injector for abdominal scanners in 60 patients].

The intravenous injection of a contrast medium is carried out in more than 80% of all the patients undergoing abdominal CT. The use of a constant-flow two-phase injector has several advantages in practice: possibility to vary the injections, safety, easy use, reproducibility, overall quality of the results and possibility to reduce the dose of contrast medium. The routine use of such equipment seems to be indispensable at present.