5 results on '"Kirchgässner M"'
Search Results
2. Muscle fatigue revisited - Insights from optically pumped magnetometers
- Author
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Justus Marquetand, Christoph Braun, Romano A, Baek S, Davide Sometti, Dax J, Chen H, Righetti G, Kirchgässner M, Middelmann T, Lorenzo Semeia, Staber D, Cornelius Kronlage, Broser P, Oppold J, and Heilos J
- Subjects
Materials science ,Muscle fatigue ,medicine.diagnostic_test ,Magnetometer ,Isometric exercise ,Rectus femoris muscle ,Electromyography ,Neurophysiology ,Signal ,law.invention ,law ,Muscular fatigue ,medicine ,Biomedical engineering - Abstract
Muscle fatigue is well characterized electromyographically, nevertheless only information about summed potential differences is detectable. In contrast, recently developed quantum sensors optically pumped magnetometers (OPMs) offer the advantage of recording both the electrical current propagation in the muscle as well as its geometry, by measuring the magnetic field generated by the muscular action potentials. Magnetomyographic investigation of muscle fatigue is still lacking and it is an open question whether fatigue is characterized similarly in magnetomyography (MMG) compared to electromyography (EMG). Herein, we investigated the muscle fatigue during a 3×1-min strong isometric contraction of the rectus femoris muscle of 12 healthy subjects using simultaneous EMG-MMG (4-channel surface EMG and 4 OPM along the rectus femoris muscle).Both EMG and MMG showed the characteristic frequency decrease in the signal magnitude during isometric contraction, which is typical for muscle fatigue. In addition, it was shown that the main part of this frequency decrease seems to occur in the circular component of the magnetic field around the muscle fibers and less longitudinally along the muscle fibers. Overall, these results show not only that magnetomyography is capable of reproducing the electromyographic standards in identifying muscular fatigue, but it also adds relevant information about the spatial characterization of the signal. Therefore, OPM-MMG offers new insights for the study of muscular activity and might serve as a new, supplementary neurophysiological method.
- Published
- 2021
- Full Text
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3. Risk factors for nonidiopathic and idiopathic facial nerve palsies: findings of a retrospective study.
- Author
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Kirchgässner M, Böhm-Gonzalez S, von Fraunberg J, Kleiser B, Liebe S, Kessler C, Sulyok M, Grimm A, and Marquetand J
- Subjects
- Humans, Retrospective Studies, Risk Factors, Male, Female, Middle Aged, Adult, Aged, Adolescent, Facial Nerve Diseases epidemiology, Facial Nerve Diseases diagnosis, Young Adult, Aged, 80 and over, Magnetic Resonance Imaging, Facial Paralysis epidemiology, Facial Paralysis diagnosis, Facial Paralysis etiology
- Abstract
Background: Idiopathic (IF) and nonidiopathic facial (NIF) nerve palsies are the most common forms of peripheral facial nerve palsies. Various risk factors for IF palsies, such as weather, have been explored, but such associations are sparse for NIF palsies, and it remains unclear whether certain diagnostic procedures, such as contrast agent-enhanced cerebral magnetic resonance imaging (cMRI), are helpful in the differential diagnosis of NIF vs. IF., Methods: In this retrospective, monocentric study over a five-year period, the medical reports of 343 patients with peripheral facial nerve palsy were analysed based on aetiology, sociodemographic factors, cardiovascular risk factors, consultation time, diagnostic procedures such as cMRI, and laboratory results. We also investigated whether weather conditions and German Google Trends data were associated with the occurrence of NIF. To assess the importance of doctors' clinical opinions, the documented anamneses and clinical examination reports were presented and rated in a blinded fashion by five neurology residents to assess the likelihood of NIF., Results: A total of 254 patients (74%) had IF, and 89 patients (26%) had NIF. The most common aetiology among the NIF patients was the varicella zoster virus (VZV, 45%). Among the factors analysed, efflorescence (odds ratio (OR) 17.3) and rater agreement (OR 5.3) had the highest associations with NIF. The day of consultation (Friday, OR 3.6) and the cMRI findings of contrast enhancement of the facial nerve (OR 2.3) were also risk factors associated with NIF. In contrast, the local weather, Google Trends data, and cardiovascular risk factors were not associated with NIF., Conclusion: The findings of this retrospective study highlight the importance of patient history and careful inspections to identify skin lesions for the differential diagnosis of acute facial nerve palsy. Special caution is advised for hospital physicians during the tick season, as a surge in NIF cases can lead to a concomitant increase in IF cases, making it challenging to choose adequate diagnostic methods., (© 2024. The Author(s).)
- Published
- 2024
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4. Muscle Fatigue Revisited - Insights From Optically Pumped Magnetometers.
- Author
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Sometti D, Semeia L, Baek S, Chen H, Righetti G, Dax J, Kronlage C, Kirchgässner M, Romano A, Heilos J, Staber D, Oppold J, Middelmann T, Braun C, Broser P, and Marquetand J
- Abstract
So far, surface electromyography (sEMG) has been the method of choice to detect and evaluate muscle fatigue. However, recent advancements in non-cryogenic quantum sensors, such as optically pumped magnetometers (OPMs), enable interesting possibilities to flexibly record biomagnetic signals. Yet, a magnetomyographic investigation of muscular fatigue is still missing. Here, we simultaneously used sEMG (4 surface electrode) and OPM-based magnetomyography (OPM-MMG, 4 sensors) to detect muscle fatigue during a 3 × 1-min isometric contractions of the left rectus femoris muscle in 7 healthy participants. Both signals exhibited the characteristic spectral compression distinctive for muscle fatigue. OPM-MMG and sEMG slope values, used to quantify the spectral compression of the signals, were positively correlated, displaying similarity between the techniques. Additionally, the analysis of the different components of the magnetic field vector enabled speculations regarding the propagation of the muscle action potentials (MAPs). Altogether these results show the feasibility of the magnetomyographic approach with OPMs and propose a potential alternative to sEMG for the study of muscle fatigue., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Sometti, Semeia, Baek, Chen, Righetti, Dax, Kronlage, Kirchgässner, Romano, Heilos, Staber, Oppold, Middelmann, Braun, Broser and Marquetand.)
- Published
- 2021
- Full Text
- View/download PDF
5. What are the infectious larvae in Ascaris suum and Trichuris muris?
- Author
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Kirchgässner M, Schmahl G, Al-Quraishy S, Ghaffar FA, and Mehlhorn H
- Subjects
- Animals, Ascariasis parasitology, Culture Media chemistry, Mice, Microscopy, Microscopy, Electron, Transmission, Molting, Trichuriasis parasitology, Ascaris suum anatomy & histology, Ascaris suum ultrastructure, Larva anatomy & histology, Larva ultrastructure, Trichuris anatomy & histology, Trichuris ultrastructure
- Abstract
In the present study, larvae of Ascaris suum and Trichuris muris were investigated by light and electron microscopy after incubation in a hatching medium containing 89% phosphate-buffered saline (pH 7.4), 10% RPMI-1640 and 1% sodiumhypochlorite at 40 and 37 degrees C, respectively. The larvae were obtained from fertilised eggs of the worms during defined phases of development (A. suum, 36th-50th day of development; T. muris, once a week from week 16 to 20). Light and electron micrographs of the larvae gave evidence that the third larval stage of A. suum is probably the infectious stage. The first moult of the larvae had already taken place before the 36th day of incubation starting at day 1. After 36 days of incubation, only the second larval stage was found within eggs. Some of these larvae were coated by a separated sheath so that a second moult of the larvae is reasonable. On the other hand, no sheathed larvae of T. muris were found in the eggs incubated for 20 weeks in distilled water. No signs of moult were seen for 20 weeks neither on light nor on the electron micrographs. Therefore, in T. muris, the first larval stage is the infectious stage, which was proven by means of re-infections of mice 16, 18 or 20 weeks after incubation of the eggs.
- Published
- 2008
- Full Text
- View/download PDF
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