Objective: The aim of this study was to elucidate the relationship between the impairment of excitation-contraction (E-C) coupling and anti-ryanodine receptor (RyR) antibody in patients with myasthenia gravis (MG).
Methods: Masseteric compound muscle action potential (CMAP) and mandibular movement-related potentials (MRPs) were recorded simultaneously after stimulating the trigeminal motor nerve with a needle electrode. The E-C coupling time (ECCT) was calculated as the latency difference between CMAP and MRP. For each patient, we selected a representative data set when there was no abnormal decrement in response to repetitive nerve stimulation. The 26 data sets were divided into an anti-RyR-positive group (n=12) and an anti-RyR-negative group (n=14).
Results: Masseteric ECCT was significantly longer (p=0.017) in anti-RyR-positive group (median, mean, range; 3.6, 3.8, 3.0-5.9 ms) than in anti-RyR-negative group (3.1, 3.1, 2.7-4.0) although there were no significant differences in masseteric CMAP amplitude and % decrement between the two groups. The bite force was significantly lower in anti-RyR-positive group than in normal controls.
Conclusions: Presence of anti-RyR antibodies is associated with significantly prolonged masseteric ECCT compared to absence of the antibodies in MG.
Significance: Anti-RyR antibody contributes to E-C coupling impairment in the masseter muscle in patients with MG.
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http://dx.doi.org/10.1016/j.clinph.2011.10.038 | DOI Listing |
Org Biomol Chem
January 2025
Department of Chemistry, CMS College Kottayam (Autonomous), Kottayam, Kerala, 686001, India.
The Suzuki-Miyaura Coupling (SMC) reaction is a powerful method for forming carbon-carbon bonds in organic synthesis. Recent advancements in SMC reactions have introduced first-row transition metal catalysts, with zinc garnering significant interest due to its cost-effective and eco-friendly nature. Despite progress in experimental protocols, the mechanistic details of zinc-catalyzed SMC reactions are limited.
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December 2024
State Key Laboratory of ASIC and System, Shanghai Institute of Intelligent Electronics & Systems, School of Microelectronics, Fudan University, Shanghai 200433, China.
The trapping mechanism at the AlGaN/GaN interface in the p-GaN high electron mobility transistors (HEMTs) and its impact on the turn-on characteristics of direct-coupled FET logic (DCFL) inverters were investigated across various supply voltages () and test frequencies (). The frequency-conductance method identified two trap states at the AlGaN/GaN interface (trap activation energy - ranges from 0.345 eV to 0.
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December 2024
C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
Background: Cerebrospinal fluid (CSF) motion and pulsatility has been proposed to play a crucial role in clearing brain waste. Although its driving forces remain debated, increasing evidence suggests that large amplitude vasomotion drives such CSF fluctuations. Recently, a fast blood-oxygen-level-dependent (BOLD) fMRI sequence was used to measure the coupling between CSF fluctuations and low-frequency hemodynamic oscillations in the human cortex.
View Article and Find Full Text PDFAdv Mater
December 2024
Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan, 411105, China.
HfO-based multi-bit ferroelectric memory combines non-volatility, speed, and energy efficiency, rendering it a promising technology for massive data storage and processing. However, some challenges remain, notably polarization variation, high operation voltage, and poor endurance performance. Here we show Hf ZrO (x = 0.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Department of Chemistry, CMS College Kottayam (Autonomous) Mahatma Gandhi University, Kottayam, Kerala, 686001, India.
A detailed theoretical study delving into the molecular mechanisms of the Ullmann-type -arylation reactions catalyzed by manganese and zinc metal ions has been investigated with the aid of the density functional theory (DFT) method. In contrast to the redox-active mechanisms proposed for classical Ullmann-type condensation reaction, a redox-neutral mechanism involving σ-bond metathesis emerged as the most appealing pathway for the investigated high-valent Mn(II) and Zn(II)-catalyzed -arylation reactions. The mechanism remains invariant with respect to the nature of the central metal, ligand, base, This unusuality in the mechanism has been dissected by considering three cases: ligand-free and ligand-assisted Mn(II)-catalyzed -arylation reaction and ligand-assisted Zn(II)-catalyzed -arylation reactions.
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