Disturbance in the blood supply to the brain causes a stroke or cerebrovascular accident. This can be due to ischemia caused by blockage (thrombosis, arterial embolism) or a hemorrhage. In this study, the feasibility of basic electrical impedance technique for monitoring such damage was analyzed using a computerized model. Simulations were conducted on a realistic 3D numerical model of the head. Tissues were assumed to act as linear isotropic volume conductors, and the quasi-static approximation was applied. Electrical potentials were calculated by solving Poisson's equation, using the finite volume method and the successive over relaxation method. Left-right asymmetry was calculated for several conductivities and volumes of the damaged region. The results were compared with the left-right asymmetry in a head model with normal brain. A negative asymmetry was revealed for blockage (i.e. the potential amplitude over the ischemic hemisphere was greater than that over the intact hemisphere). In case of hemorrhage, a positive asymmetry was found. Furthermore, correlation was found between the location of the damaged region and the electrodes with significant asymmetry. The 3D numerical simulations revealed that the electrical conductivity and the size of the damaged tissue have an effect on the left-right asymmetry of the surface potential.
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http://dx.doi.org/10.1016/j.medengphy.2015.02.011 | DOI Listing |
Biophys Physicobiol
September 2024
Department of Cell Biology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Visceral organs in vertebrates are arranged with left-right asymmetry; for example, the heart is located on the left side of the body. Cilia at the node of mouse early embryos play an essential role in determining this left-right asymmetry. Using information from the anteroposterior axis, motile cilia at the central region of the node generate leftward nodal flow.
View Article and Find Full Text PDFNeuroimage
January 2025
Department of Genetics, Harvard Medical School, Boston, MA, USA; Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA. Electronic address:
Left-right asymmetry of the human brain is widespread through its anatomy and function. However, limited microscopic understanding of it exists, particularly for anatomical asymmetry where there are few well-established animal models. In humans, most brain regions show subtle, population-average regional asymmetries in thickness or surface area, alongside a macro-scale twisting called the cerebral petalia in which the right hemisphere protrudes anteriorly past the left.
View Article and Find Full Text PDFDev Growth Differ
January 2025
Division of Anatomy and Developmental Biology, Department of Anatomy, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Sonic Hedgehog (Shh), encoding an extracellular signaling molecule, is vital for heart development. Shh null mutants show congenital heart disease due to left-right asymmetry defects stemming from functional anomaly in the midline structure in mice. Shh signaling is also known to affect cardiomyocyte differentiation, endocardium development, and heart morphogenesis, particularly in second heart field (SHF) cardiac progenitor cells that contribute to the right ventricle, outflow tract, and parts of the atrium.
View Article and Find Full Text PDFClin Orthop Relat Res
January 2025
School of Biomedical Sciences, The University of Queensland, St. Lucia, Australia.
Background: Adolescent idiopathic scoliosis (AIS) is characterized by an asymmetrical formation of the spine and ribcage. Recent work provides evidence of asymmetrical (right versus left side) paraspinal muscle size, composition, and activation amplitude in adolescents with AIS. Each of these factors influences muscle force generation.
View Article and Find Full Text PDFCells
December 2024
Laboratoire de Biologie du Développement, LBD, CNRS UMR7622, INSERM U1156, Sorbonne Université, F-75005 Paris, France.
The formation of the embryonic left-right axis is a fundamental process in animals, which subsequently conditions both the shape and the correct positioning of internal organs. During vertebrate early development, a transient structure, known as the left-right organizer, breaks the bilateral symmetry in a manner that is critically dependent on the activity of motile and immotile cilia or asymmetric cell migration. Extensive studies have partially elucidated the molecular pathways that initiate left-right asymmetric patterning and morphogenesis.
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