For several years, cell culture techniques have been physiologically relevant to understand living organisms both structurally and functionally, aiming at preserving as carefully as possible the in vivo integrity and function of the cells. However, when studying cardiac cells, glass or plastic Petri dishes and culture-coated plates lack important cues that do not allow to maintain the desired phenotype, especially for primary cell culture. In this work, we show that microscaffolds made with polydimethylsiloxane (PDMS) enable modulating the stiffness of the surface of the culture substrate and this originates different patterns of adhesion, self-organization, and synchronized or propagated activity in the culture of chick embryonic cardiomyocytes. Thanks to the calcium imaging technique, we found that the substrate stiffness affected cardiomyocyte adhesion, as well as the calcium signal propagation in the formed tissue. The patterns of activity shown by the calcium fluorescence variations are reliable clues of the functional organization achieved by the cell layers. We found that PDMS substrates with a stiffness of 25 kPa did not allow the formation of cell layers and therefore the optimal propagation of the intracellular calcium signals, while softer PDMS substrates with Young’s modulus within the physiological in vivo reported range did permit synchronized and coordinated contractility and intracellular calcium activity. This type of methodology allows us to study phenomena such as arrhythmias. For example, the occurrence of synchronized activity or rotors that can initiate or maintain cardiac arrhythmias can be reproduced on different substrates for study, so that replacement tissues or patches can be better designed.

Quantification of visceral fat by ultrasound during pregnancy has been occupying a prominent role in the medical literature, since it does not use ionizing radiation present in tomography, the high cost of nuclear magnetic resonance imaging in addition to the ineffectiveness of body mass index measuring during pregnancy, as indicator of the quantity of accumulated visceral fat. Different ultrasound measurements on the abdomen have been proposed as indicators of the amount of visceral fat. A major example is the Armellini method, which measures at the level of xipho-pubic line with the transducer positioned one centimeter above the umbilical scar and the measurement have to be made from the internal edge of the linea alba, or inner side of the abdominal rectus muscles, until the anterior aortic wall. The measurement of maternal Armellini space will be according the proposal at study of Martin AM et.al (Martin AM, Berger H, Nisenbaum R et al. Abdominal visceral adiposity in the first trimester predicts glucose intolerance in later pregnancy. Diabetes Care 2009;32:1308-1310) using convex probe placed 1cm above the maternal umbilical scar at median sagittal plane position, and using electronic calipers to measure the distance from linea alba to aortic crossa. The final measurement was achieved by the mean measurement among maternal breath cicle at inspiration and expiration.