Marcin Bednarz

AGH University of Krakow

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Karin Jurkat‐Rott

Universität Ulm

Chunxiang Fan

Qiqihar University

Frank Lehmann‐Horn

Universität Ulm

James R. Groome

Idaho State University

Elena Sánchez

Universidad Complutense de Madrid

J.F. Martí-Massó

Biogipuzkoa Health Research Institute

Catharine E. Krebs

Physicians Committee for Responsible Medicine

Alberto Bergareche

Biomedical Research Networking Center on Neurodegenerative Diseases

Javier Ruiz‐Martínez

Biogipuzkoa Health Research Institute

Coro Paisán‐Ruiz

Biogen (United States)

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Annexon Biosciences (United States)

Defence Terrain Research Laboratory

Institut National de Recherches Archéologiques Préventives

Ministère de la Culture

Biogipuzkoa Health Research Institute

Biomedical Research Networking Center on Neurodegenerative Diseases

Instituto de Salud Carlos III

University Medical Center

Radboud University Nijmegen

Radboud University Medical Center

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A novel Ile1455Thr variant in the skeletal muscle sodium channel alpha-subunit in a patient with a severe adult-onset proximal myopathy with electrical myotonia and a patient with mild paramyotonia phenotype

Neuromuscular Disorders (2016)

Marcin Bednarz Bas C. Stunnenberg Benno Küsters Erik‐Jan Kamsteeg Christiaan G. J. Saris

Alpha (finance)

Myotonia congenita

10.1016/j.nmd.2016.09.023

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Citations (11)

Skeletal Muscle Calcium Channel Mutation R528G: Enhanced Channel Inactivation And Omega-current At Hyperpolarization Contribute To Hypokalemic Periodic Paralysis.

Journal of Neurological Research And Therapy (2016)

Marcin Bednarz Yuwei Da Frank Lehmann‐Horn Chunxiang Fan Jens Schallner

Abstract Autosomal dominant inherited hypokalemic periodic paralysis (HypoPP) is caused by S4 voltage sensor mutations in skeletal muscle CaV1.1 calcium or NaV1.4 sodium channels. In the present study, a small German family with the known CaV1.1-R528G is described. The phenotype consists of short and infrequent episodes of limb weakness with ictal respiratory and cardiac involvement. There is incomplete penetrance in women, and acetazolamide is beneficial in two patients also taking daily potassium. Expression of the mutation in the GLT mouse muscle cell line revealed accelerated kinetics of inactivation by twofold, a left-shift of the steady-state inactivation curve by 13mV and a reduced recovery from fast inactivation by up to 39%. These changes suggest a stabilization of the inactivated state. Additional significant slowing of activation may support a second open state with differing ion selectivity or decreased activation of calcium-activated potassium channels and thereby contribute to weakness similar to other CaV1.1 mutations. Also, as documented for other HypoPP mutants, we found a hyperpolarization-induced inward guanidinium current of 22nS/nF which can be interpreted as an omega current along the voltage sensor gating pore that leads to a gain- of- function at potentials near the resting membrane potential. This finding can explain the long-lasting depolarizations that are known to lead to paralysis. The omega current is large enough so that a relatively mild hypokalemic trigger of 2.4mM already produces episodes of weakness in vivo.

Hypokalemic periodic paralysis

Penetrance

Periodic paralysis

Muscle weakness

Hyperpolarization

10.14302/issn.2470-5020.jnrt-16-993

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Citations (2)

Wireless Local Area Networks Threat Detection Using 1D-CNN

Sensors (2023)

Marek Natkaniec Marcin Bednarz

Wireless Local Area Networks (WLANs) have revolutionized modern communication by providing a user-friendly and cost-efficient solution for Internet access and network resources. However, the increasing popularity of WLANs has also led to a rise in security threats, including jamming, flooding attacks, unfair radio channel access, user disconnection from access points, and injection attacks, among others. In this paper, we propose a machine learning algorithm to detect Layer 2 threats in WLANs through network traffic analysis. Our approach uses a deep neural network to identify malicious activity patterns. We detail the dataset used, including data preparation steps, such as preprocessing and division. We demonstrate the effectiveness of our solution through series of experiments and show that it outperforms other methods in terms of precision. The proposed algorithm can be successfully applied in Wireless Intrusion Detection Systems (WIDS) to enhance the security of WLANs and protect against potential attacks.

10.3390/s23125507

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Transient compartment-like syndrome and normokalaemic periodic paralysis due to a Cav1.1 mutation

Brain (2013)

Chunxiang Fan Frank Lehmann‐Horn Marc‐André Weber Marcin Bednarz James R. Groome

We studied a two-generation family presenting with conditions that included progressive permanent weakness, myopathic myopathy, exercise-induced contracture before normokalaemic periodic paralysis or, if localized to the tibial anterior muscle group, transient compartment-like syndrome (painful acute oedema with neuronal compression and drop foot). 23Na and 1H magnetic resonance imaging displayed myoplasmic sodium overload, and oedema. We identified a novel familial Cav1.1 calcium channel mutation, R1242G, localized to the third positive charge of the domain IV voltage sensor. Functional expression of R1242G in the muscular dysgenesis mouse cell line GLT revealed a 28% reduced central pore inward current and a −20 mV shift of the steady-state inactivation curve. Both changes may be at least partially explained by an outward omega (gating pore) current at positive potentials. Moreover, this outward omega current of 27.5 nS/nF may cause the reduction of the overshoot by 13 mV and slowing of the upstroke of action potentials by 36% that are associated with muscle hypoexcitability (permanent weakness and myopathic myopathy). In addition to the outward omega current, we identified an inward omega pore current of 95 nS/nF at negative membrane potentials after long depolarizing pulses that shifts the R1242G residue above the omega pore constriction. A simulation reveals that the inward current might depolarize the fibre sufficiently to trigger calcium release in the absence of an action potential and therefore cause an electrically silent depolarization-induced muscle contracture. Additionally, evidence of the inward current can be found in 23Na magnetic resonance imaging-detected sodium accumulation and 1H magnetic resonance imaging-detected oedema. We hypothesize that the episodes are normokalaemic because of depolarization-induced compensatory outward potassium flux through both delayed rectifiers and omega pore. We conclude that the position of the R1242G residue before elicitation of the omega current is decisive for its conductance: if the residue is located below the gating pore as in the resting state then outward currents are observed; if the residue is above the gating pore because of depolarization, as in the inactivated state, then inward currents are observed. This study shows for the first time that functional characterization of omega pore currents is possible using a cultured cell line expressing mutant Cav1.1 channels. Likewise, it is the first calcium channel mutation for complicated normokalaemic periodic paralysis.

10.1093/brain/awt300

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Citations (38)

Chapitre 3. Le cadre naturel

Éditions de la Maison des sciences de l’homme eBooks (1992)

Jean-Claude Blanchet Marc Talon Luc Laporte Hervé Guy Frédérique Blaizot

Ce document a été généré automatiquement le 26 août 2022.Il est issu d'une numérisation par reconnaissance optique de caractères.

10.4000/books.editionsmsh.37283

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SCN4Apore mutation pathogenetically contributes to autosomal dominant essential tremor and may increase susceptibility to epilepsy

Human Molecular Genetics (2015)

Alberto Bergareche Marcin Bednarz Elena Sánchez Catharine E. Krebs Javier Ruiz‐Martínez

Essential tremor (ET) is the most prevalent movement disorder, affecting millions of people in the USA. Although a positive family history is one of the most important risk factors for ET, the genetic causes of ET remain unknown. In an attempt to identify genetic causes for ET, we performed whole-exome sequencing analyses in a large Spanish family with ET, in which two patients also developed epilepsy. To further assess pathogenicity, site-directed mutagenesis, mouse and human brain expression analyses, and patch clamp techniques were performed. A disease-segregating mutation (p.Gly1537Ser) in the SCN4A gene was identified. Posterior functional analyses demonstrated that more rapid kinetics at near-threshold potentials altered ion selectivity and facilitated the conductance of both potassium and ammonium ions, which could contribute to tremor and increase susceptibility to epilepsy, respectively. In this report, for the first time, we associated the genetic variability of SCN4A with the development of essential tremor, which adds ET to the growing list of neurological channelopathies.

10.1093/hmg/ddv410

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Citations (38)

Remote Radio Frequency Sensing Based on 5G New Radio Positioning Reference Signals

Sensors (2025)

Marcin Bednarz Tomasz P. Zieliński

In this paper, the idea of a radar based on orthogonal frequency division multiplexing (OFDM) is applied to 5G NR Positioning Reference Signals (PRS). This study demonstrates how the estimation of the communication channel using the PRS can be applied for the identification of objects moving near the 5G NR receiver. In this context, this refers to a 5G NR base station capable of detecting a high-speed train (HST). The anatomy of a 5G NR frame as a sequence of OFDM symbols is presented, and different PRS configurations are described. It is shown that spectral analysis of time-varying channel impulse response weights, estimated with the help of PRS pilots, can be used for the detection of transmitted signal reflections from moving vehicles and the calculation of their time and frequency/Doppler shifts. Different PRS configurations with varying time and frequency reference signal densities are tested in simulations. The peak-to-noise-floor ratio (PNFR) of the calculated radar range-velocity maps (RVM) is used for quantitative comparison of PRS-based radar scenarios. Additionally, different echo signal strengths are simulated while also checking various observation window lengths (FFT lengths). This study proves the practicality of using PRS pilots in remote sensing; however, it shows that the most dense configurations do not provide notable improvements, while also demanding considerably more resources.

10.3390/s25020337

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Wpływ wybranych paliw na opóźnienie okresu samozapłonu

Logistyka (2015)

K. Górski W. Lotko Rafał Longwic Marcin Bednarz

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A Novel Cav1.1-K1245Q Mutation Leading to Hypokalemic Periodic Paralysis

Biophysical Journal (2013)

Marcin Bednarz Chunxiang Fan Frank Lehmann‐Horn Karin Jurkat‐Rott