Search results for "ion channel"
showing 10 items of 567 documents
Lack of SCN1A Mutations in Familial Febrile Seizures
2002
Summary: Purpose: Mutations in the voltage-gated sodium channel subunit gene SCN1A have been associated with febrile seizures (FSs) in autosomal dominant generalized epilepsy with febrile seizures plus (GEFS+) families and severe myoclonic epilepsy of infancy. The present study assessed the role of SCN1A in familial typical FSs. Methods: FS families were selected throughout a collaborative study of the Italian League Against Epilepsy. For each index case, the entire coding region of SCN1A was screened by denaturant high-performance liquid chromatography. DNA fragments showing variant chromatograms were subsequently sequenced. Results: Thirty-two FS families accounting for 91 affected indiv…
From non-excitable single-cell to multicellular bioelectrical states supported by ion channels and gap junction proteins: Electrical potentials as di…
2019
Endogenous bioelectric patterns within tissues are an important driver of morphogenesis and a tractable component of a number of disease states. Developing system-level understanding of the dynamics by which non-neural bioelectric circuits regulate complex downstream cascades is a key step towards both, an evolutionary understanding of ion channel genes, and novel strategies in regenerative medicine. An important capability gap is deriving rational modulation strategies targeting individual cells' bioelectric states to achieve global (tissue- or organ-level) outcomes. Here, we develop an ion channel-based model that describes multicellular states on the basis of spatio-temporal patterns of …
The diversity of GABAA receptors. Pharmacological and electrophysiological properties of GABAA channel subtypes.
1998
The amino acid gamma-aminobutyric-acid (GABA) prevails in the CNS as an inhibitory neurotransmitter that mediates most of its effects through fast GABA-gated Cl(-)-channels (GABAAR). Molecular biology uncovered the complex subunit architecture of this receptor channel, in which a pentameric assembly derived from five of at least 17 mammalian subunits, grouped in the six classes alpha, beta, gamma, delta, sigma and epsilon, permits a vast number of putative receptor isoforms. The subunit composition of a particular receptor determines the specific effects of allosterical modulators of the GABAARs like benzodiazepines (BZs), barbiturates, steroids, some convulsants, polyvalent cations, and et…
A Trajectory-Driven 3D Non-Stationary mm-Wave MIMO Channel Model for a Single Moving Point Scatterer
2021
This paper proposes a new non-stationary three-dimensional (3D) channel model for a physical millimeter wave (mm-Wave) multiple-input multiple-output (MIMO) channel. This MIMO channel model is driven by the trajectory of a moving point scatterer, which allows us to investigate the impact of a single moving point scatterer on the propagation characteristics in an indoor environment. Starting from the time-variant (TV) channel transfer function, the temporal behavior of the proposed non-stationary channel model has been analyzed by studying the TV micro-Doppler characteristics and the TV mean Doppler shift. The proposed channel model has been validated by measurements performed in an indoor e…
Calcium binding and ionic conduction in single conical nanopores with polyacid chains: model and experiments.
2012
Calcium binding to fixed charge groups confined over nanoscale regions is relevant to ion equilibrium and transport in the ionic channels of the cell membranes and artificial nanopores. We present an experimental and theoretical description of the dissociation equilibrium and transport in a single conical nanopore functionalized with pH-sensitive carboxylic acid groups and phosphonic acid chains. Different phenomena are simultaneously present in this basic problem of physical and biophysical chemistry: (i) the divalent nature of the phosphonic acid groups fixed to the pore walls and the influence of the pH and calcium on the reversible dissociation equilibrium of these groups; (ii) the asym…
Polycystin-1 downregulation induces ERK-dependent mTOR pathway activation in a cellular model of psoriasis
2018
Psoriatic plaques tend to localize to the knees and elbows, areas that are particularly subject to mechanical stress resulting from bending and friction. Moreover, plaques often develop at sites of mechanical trauma or injury (Koebner phenomenon). Nevertheless, mechanotransduction has never been linked to psoriasis. Polycystins (polycystin-1, PC1; polycystin-2, PC2) are mechanosensitive molecules that function as key regulators of cellular mechanosensitivity and mechanotransduction. The aim of this in vitro study was to investigate the role of polycystins in the development of psoriasis. We showed that PC1 knockdown in HaCaT cells led to an elevated mRNA expression of psoriasis-related biom…
Disorder-induced single-mode transmission.
2017
Localized states trap waves propagating in a disordered potential and play a crucial role in Anderson localization, which is the absence of diffusion due to disorder. Some localized states are barely coupled with neighbours because of differences in wavelength or small spatial overlap, thus preventing energy leakage to the surroundings. This is the same degree of isolation found in the homogeneous core of a single-mode optical fibre. Here we show that localized states of a disordered optical fibre are single mode: the transmission channels possess a high degree of resilience to perturbation and invariance with respect to the launch conditions. Our experimental approach allows identification…
The cGMP-gated channel of the rod photoreceptor — a new type of channel structure?
1990
Recents findings from Numa's laboratory reveal that there might exist a wider variety in channel protein structure than originally anticipated. Recently, the cloning has been reported of the first cGMP-gated ion channel, the vertebrate rod photoreceptor which is activated by cGMP acting from the inside of the rod outer segment membrane
The effect of body shape and gender on wireless Body Area Network on-body channels
2010
Technological advancements have made possible the emergence of Body Area Networks (BANs). There are numerous on-body channel characterizations in the literature performed on a phantom or a single human subject. In this paper, using multiple subjects, we consider the effect of body shape and gender on the on-body channel. A characterization of a narrowband on-body to on-body channel among different subjects is presented. The paper investigates the relationship between the propagation and the subject's physical characteristics. The investigation is performed at 2360 MHz; the new medical band undergoing FCC approval. Our results show that the path loss in women is less than that in men and the…
Use of geomorphological units to improve drainage network extraction from a DEM
1999
Abstract Drainage networks are one of the main elements characterizing basins, and network topology and geometry form the basis of many hydrological and geomorphological models ( eg Geomorphological Unitary Hydrograph). The identification and manual delineation of channel networks from maps or aerial photographs requires much time and effort. In the last two decades, algorithms and procedures for automated extraction of drainage networks from digital elevation data have been developed and implemented in many specialized software applications. Nevertheless, automatically delineated channel networks do not always show close agreement with manually delineated networks. This paper describes a c…