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Publications
Publications (49)
Key points:
This study examines conduction in peripheral nerves and its use dependence in TTXr sodium channel (Nav 1.8, Nav 1.9) knock out and wildtype animals. We observed use-dependent decrease of single fibres' and compound action potential's amplitude in peripheral mouse C-fibres (wildtype). This matches the previously published hypothesis tha...
The effect of regional anesthesia of the brachial plexus on the size and intensity of the histamine-induced axon reflex flare (neurogenic inflammation) of the forearm and the upper arm was compared to that of the contralateral arm as control in humans. No changes in the axon reflex could be assessed. Thus the lateral spread of the axon reflex flare...
Microneurography was used in healthy human subjects to record action potentials from unmyelinated nerve fibers (C units) in cutaneous fascicles of the peroneal nerve.
Activity-dependent slowing ( n = 96) and transcutaneous electrical thresholds ( n = 67) were determined. Eight units were sympathetic efferents according to their responses to sympath...
1. To study post-excitatory changes of conduction velocity, action potentials were recorded from 132 unmyelinated nerve fibres (C fibres) in cutaneous fascicles of the peroneal nerve using microneurography in healthy human subjects. The 'marking' technique was used to assess responsiveness to mechanical and heat stimuli or sympathetic reflex provoc...
Zusammenfassung
Zur Unterstützung der Entscheidungsträger werden in der SARS-CoV-2-Pandemie unterschiedlichste Daten erhoben, um ein möglichst genaues Lagebild zur Steuerung von Pandemiemaßnahmen zu erhalten. Nur wenig hilfreich sind dabei sowohl Papier und Stift als auch der Versand einzelner medienbruchbehafteter Dateien, die später zusammengefüg...
Due to the lack of data on asymptomatic SARS-CoV-2-positive persons in healthcare institutions, they represent an inestimable risk. Therefore, the aim of the current study was to evaluate the first 1,000,000 reported screening tests of asymptomatic staff, patients, residents, and visitors in hospitals and long-term care (LTC) facilities in the Stat...
Zusammenfassung
Die aktuelle COVID-19-Pandemie stellt vieles auf die Probe, allen voran die multisektorale Zusammenarbeit sowohl zwischen den Akteuren im Gesundheitswesen als auch mit Akteuren aus anderen Bereichen wie Politik, Wirtschaft, Sicherheit, Bildung und Kommunikation. Inhaltliche Vorbereitungen in Form von Pandemieplänen, Zuständigkeitsre...
Despite major efforts, food safety and food fraud issues continue to appear, showing the need for an improved risk anticipation to enhance consumer protection. To this end, we need a holistic view on the food production beyond the classical farm to fork principle and consider developments in- and outside the food chain. Commodity flows and prices a...
The sodium channel NaV1.7 contributes to action potential generation and propagation. Loss-of-function mutations in patients lead to congenital indifference to pain, though it remains unclear where on the way from sensory terminals to CNS the signalling is disrupted. We confirm that conditional deletion of NaV1.7 in advillin expressing sensory neur...
Das bayerische Landesamt für Gesundheit und Lebensmittelsicherheit (LGL) verfolgt seit Anfang 2014 die Etablierung eines Frühwarnsystems in der Lebensmittelüberwachung. Ziel ist es, durch eine umfassende Sicht auf die Lebensmittelproduktion Gesundheitsrisiken und Betrugspotentiale für Lebensmittel so früh wie möglich zu erkennen. Hierzu werden Einf...
The upregulation of the TTX resistant voltage-gated sodium channel NaV1.9 has previously been associated with inflammatory hyperalgesia. Na1.9 knock-out (KO) mice, however, did not appear insensitive in conventional tests of acute nociception. Using electrophysiological, neurochemical and behavioral techniques, we now show NaV1.9 null mice exhibit...
Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV1.7-mediated pain...
Since the first risk evaluation of Alternaria toxins by the European Food Safety Authority (EFSA) in 2011, new stable isotope dilution assays for tenuazonic acid (TA) broadened and deepened the data for exposure assessment. Moreover, recently unraveled high contents of TA in infant food based on sorghum/millet required an updated risk assessment. W...
Recent and past food scandals highlight the urgent need for food safety authorities to anticipate future risks in order to enable improved and proactive response mechanisms. With this goal in mind, the Bavarian Health and Food Safety Authority (LGL) has established an early warning system aimed at early identification of potential health risks and...
Seven patients diagnosed with erythromelalgia (EM) were investigated by microneurography to record from unmyelinated nerve fibers in the peroneal nerve. Two patients had characterized variants of sodium channel Nav1.7 (I848T, I228M) while no mutations of coding regions of Navs were found in 5 EM patients.Irrespective of NaV1.7 mutations, more than...
Following each action potential, C-fiber nociceptors undergo cyclical changes in excitability, including a period of superexcitability, before recovering their basal excitability state. The increase in superexcitability during this recovery cycle depends upon their immediate firing history of the axon, but also determines the instantaneous firing f...
Background:
Two transient receptor potential (TRP) channels, TRPV1 and TRPA1, have been physiologically studied with regard to noxious heat transduction. Evidence argues against these channels as sole transducers of noxious heat or cold, respectively. Moreover, in submammalian species the TRPA1 orthologue shows heat sensitivity.
Methods:
In vitr...
Bisphenol A (BPA) has attracted considerable public attention as it leaches from plastic used in food containers, is detectable in human fluids and recent epidemiologic studies link BPA exposure with diseases including cardiovascular disorders. As heart-toxicity may derive from modified cardiac electrophysiology, we investigated the interaction bet...
Steered molecular dynamics study of BPA entering the pore of the homology model of Nav1.5 via the side fenestration DIII–IV.
(MPG)
Physicochemical characteristics of BPA and local anesthetics.
(DOCX)
Steered molecular dynamics study of mexiletine entering the pore of the homology model of Nav1.5 via the side fenestration DIII–IV.
(MPG)
Steered molecular dynamics study of mexiletine entering the pore of the homology model of Nav1.5 via the selectivity filter.
(MPG)
Steered molecular dynamics study of BPA entering the pore of the homology model of Nav1.5 via the selectivity filter.
(MPG)
Action potentials from postganglionic C-fibres were recorded in healthy volunteers by microneurography in the peroneal nerve. Their responsiveness to mechanical or heat stimuli or to sympathetic reflex provocation tests was determined by transient slowing of conduction velocity following activation. Twenty units were classified as sympathetic effer...
To investigate the existence of histamine-excitable nerve fibers in the oral mucosa and to compare the response to histamine provocation in healthy volunteers with that in a small group of patients with chronic oral pain.
Thirteen healthy volunteers and six patients suffering from chronic oral pain took part in the study. Blood perfusion was monito...
Microneurography was used to record action potentials from afferent C-fibers in cutaneous fascicles of the peroneal nerve in healthy volunteers. Afferent fibers were classified according to their mechanical responsiveness to von Frey stimulation (75g) into mechano-responsive and mechano-insensitive nociceptors. Various concentrations of Endothelin1...
The mechanisms underlying the development of painful and nonpainful neuropathy associated with diabetes mellitus are unclear. We have obtained microneurographic recordings from unmyelinated fibers in eight patients with diabetes mellitus, five with painful neuropathy, and three with neuropathy without pain. All eight patients had large-fiber neurop...
Threshold tracking of individual polymodal C- and Adelta-fiber terminals was used to assess membrane potential changes induced by de- or hyperpolarizing stimuli in the isolated rat skin-nerve preparation. Constant current pulses were delivered (1 Hz) through a tungsten microelectrode inserted in the receptive field, and the current amplitude was co...
The mechanisms for the induction of primary mechanical hyperalgesia are unclear. We analyzed the neurogenic axon reflex erythema (flare) following phasic mechanical stimulation in normal and in UV-B irradiated skin. In a cross-over double blind design (n = 10), low dose of systemic lidocaine suppressed mechanical hyperalgesia in sunburned skin and...
An itch-specific neuronal pathway was recently discovered in healthy humans and animals. Here the authors report that activity in this specific pathway coincides with itch under pathophysiologic conditions in a patient with chronic pruritus. Microneurographic recordings from the symptomatic area revealed spontaneous activity in six single C-fiber a...
Vasoneuroactive substances were applied through intradermal microdialysis membranes and characterized as itch- or pain-inducing in psychophysical experiments. Histamine always provoked itching and rarely pain, capsaicin always pain but never itching. Prostaglandin E(2) (PGE(2)) led preferentially to moderate itching. Serotonin, acetylcholine, and b...
Recordings of single human peroneal C-fibres and rat saphenous C-fibres confirm two different patterns of conduction at branching points. In general, an action potential (AP) arising from one terminal branch may be propagated not only centrally, but also antidromically into the other branches of the terminal arborisation. If a stimulus activates se...
Little is known about the contribution of C-afferent fibres to chronic painful conditions in humans. We sought to investigate the role of C-fibres in the pathophysiology of pain and hyperalgesia in erythromelalgia as a model disease for chronic pain. Erythromelalgia is a condition characterized by painful, red and hot extremities, and patients ofte...
Microneurographic recordings were obtained in the peroneal nerve from 20 mechano-insensitive units (CMi) and six mechano-heat responsive C units (CMH) in healthy human subjects. Their innervation territories in the skin of the leg or foot were assessed by transcutaneous electrical stimulation with a pointed probe at intensities of 10 to 100 mA (0.2...
Microneurographic recordings were obtained in the peroneal nerve from 20 mechano-insensitive units (CMi) and six mechano-heat responsive C units (CMH) in healthy human subjects. Their innervation territories in the skin of the leg or foot were assessed by transcutaneous electrical stimulation with a pointed probe at intensities of 10 to 100 mA (0.2...
The microneurography technique was used to analyze use-dependent frequency modulation of action potential (AP) trains in human nociceptive peripheral nerves. Fifty-one single C-afferent units (31 mechano-responsive, 20 mechano-insensitive) were recorded from cutaneous fascicles of the peroneal nerve in awake human subjects. Trains of two and four s...
Microelectrode recordings of impulse activity in nociceptive C fibres were performed in cutaneous fascicles of the peroneal nerve at the knee level in healthy human subjects. Mechano-heat responsive C units (CMH), mechano-insensitive but heat-responsive (CH) as well as mechano-insensitive and heat-insensitive C units (CM(i)H(i)) were identified. A...
Upon activation nociceptors release neuropeptides in the skin provoking vasodilation and plasma protein extravasation in rodents, but only vasodilation in humans. Pivotal peptides in the induction of neurogenic inflammation comprise calcitonin gene-related peptide and substance P, the latter being suggested to act partly via degranulation of mast c...
Sodium channel blockers are approved for intravenous administration in the treatment of neuropathic pain states. Preclinical studies have suggested antihyperalgesic effects on the peripheral as well as the central nervous system. The objective of this study was to determine mechanisms of action of low-dose Lidocaine in experimental induced, seconda...
Sodium channel blockers are approved for intravenous administration in the treatment of neuropathic pain states. Preclinical studies have suggested antihyperalgesic effects on the peripheral as well as the central nervous system. The objective of this study was to determine mechanisms of action of low-dose lidocaine in experimental induced, seconda...
Axon reflex vasodilatation due to transcutaneous electrical stimulation in human skin was measured by laser Doppler imaging. Constant current pulses of 10 mA, 0.2 ms, delivered at 1 or 10 Hz for 2 min through a probe of 30 mm2 surface area did not induce a significant flare response, though this stimulus previously has been found supra-maximal for...
