Transmembrane potential induced on the internal organelle by a time-varying magnetic field: a model study

<p>Abstract</p> <p>Background</p> <p>When a cell is exposed to a time-varying magnetic field, this leads to an induced voltage on the cytoplasmic membrane, as well as on the membranes of the internal organelles, such as mitochondria. These potential changes in the organelles could have a significant impact on their functionality. However, a quantitative analysis on the magnetically-induced membrane potential on the internal organelles has not been performed.</p> <p>Methods</p> <p>Using a two-shell model, we provided the first analytical solution for the transmembrane potential in the organelle membrane induced by a time-varying magnetic field. We then analyzed factors that impact on the polarization of the organelle, including the frequency of the magnetic field, the presence of the outer cytoplasmic membrane, and electrical and geometrical parameters of the cytoplasmic membrane and the organelle membrane.</p> <p>Results</p> <p>The amount of polarization in the organelle was less than its counterpart in the cytoplasmic membrane. This was largely due to the presence of the cell membrane, which "shielded" the internal organelle from excessive polarization by the field. Organelle polarization was largely dependent on the frequency of the magnetic field, and its polarization was not significant under the low frequency band used for transcranial magnetic stimulation (TMS). Both the properties of the cytoplasmic and the organelle membranes affect the polarization of the internal organelle in a frequency-dependent manner.</p> <p>Conclusions</p> <p>The work provided a theoretical framework and insights into factors affecting mitochondrial function under time-varying magnetic stimulation, and provided evidence that TMS does not affect normal mitochondrial functionality by altering its membrane potential.</p

Short sleep duration and cardiometabolic risk: from pathophysiology to clinical evidence

reserved6noShort sleep duration has a substantial influence on the overall health of an individual. Short sleep time can be a consequence of lifestyle habits, environmental factors, or the presence of a sleep disorder, such as insomnia or sleep-disordered breathing. Short sleep time is associated with increased morbidity and mortality, mainly from cardiovascular disorders (including coronary artery disease, arrhythmias, and hypertension). Several biological mechanisms have been proposed as a possible link between short sleep duration and these diseases, such as involvement of the autonomic nervous system, endothelial function, metabolic regulation, inflammation, and the coagulation system. In this Review, we provide an overview on the effects of short sleep duration on cardiovascular health and diseases and discuss the main pathophysiological mechanisms involved, taking into account both experimental data and clinical evidence.mixedTobaldini, Eleonora; Fiorelli, Elisa M.; Solbiati, Monica; Costantino, Giorgio; Nobili, Lino; Montano, NicolaTobaldini, Eleonora; Fiorelli, Elisa M.; Solbiati, Monica; Costantino, Giorgio; Nobili, Lino; Montano, Nicol