TY - THES A1 - Schuster, Frank T1 - Untersuchungen zur Modulation der interstitiellen Laktatkonzentration im isoliert perfundierten Skelettmuskel der Ratte durch Kalzium, Koffein, Ryanodin und Dantrolen im Rahmen der Entwicklung eines minimal-invasiven Verfahrens zur Diagnostik der maligne Hyperthermie Veranlagung T1 - Investigations for modulation of interstitial lactate concentration of isolated perfused rat skeletal muscle with calcium, caffeine, ryanodine and dantrolene to develop a minimally invasive technique for diagnosing malignant hyperthermia susceptibility N2 - Die maligne Hyperthermie ist eine metabolische Muskelerkrankung, die durch eine unkontrollierte Kalzium-Freisetzung in das Zytosol der Muskelzelle zu einer Aktivierung des kontraktilen Apparates und zu einer Beschleunigung des Zellstoffwechsels führen kann. Der in-vitro-Kontraktur-Test am Skelettmuskel ist zur Zeit das einzige zuverlässige Verfahren zur Erkennung einer MH-Veranlagung. In dieser Arbeit sollte untersucht werden inwieweit die lokale Laktatkonzentration durch die Applikation von Kalzium und Koffein mit Hilfe einer Mikrodialysesonde beziehungsweise durch die systemische Infusion von Ryanodin und Dantrolen beeinflusst wird. Mit Tierschutz-Genehmigung wurden 61 Sprague-Dawley Ratten anästhesiert und post exitum über die Aorta die Hinterbeine mit Ringer-, Ryanodin- (0,25 µM, 1 µM) oder Dantrolenlösung (1 µM) perfundiert (30 ml h-1, 19-20oC). Über Mikrodialysesonden (1 µl min-1) in den Mm. adductores wurde Ringer, Sorbitol (80 mM), Kalzium (20 mM, 40 mM, 80 mM) oder Koffein (40 mM, 80 mM) appliziert und im Dialysat Laktat spektrometrisch gemessen. Bei einer relativen recovery von 77 ± 2% für Laktat in-vitro stieg die Laktatkonzentration unter Perfusion mit 20 mM, 40 mM beziehungsweise 80 mM Kalziumlösung auf 466 ± 31%, 632 ± 48% beziehungsweise 635 ± 81%, während unter Perfusion mit 40 mM und 80 mM Koffein eine relative Zunahme auf 270 ± 21% und 377 ± 21% beobachtet wurde. Unter systemischer Organperfusion mit 0,25 µM und 1 µM Ryanodinlösung und lokaler Applikation von 40 mM Koffein wurden relative Laktatanstiege von 279 ± 23% und 331 ± 19% gemessen. Dagegen stieg die relative Laktatkonzentration bei systemischer Infusion von 1 µM Dantrolenlösung und lokaler Perfusion mit 40 mM Koffein nur bis auf 193 ± 13% an. Diese methodische Untersuchung beweist, dass durch die lokale Perfusion von Kalzium und Koffein sowie die systemische Infusion von Ryanodin ein Anstieg der lokalen Laktatkonzentration induziert, beziehungsweise durch systemische Applikation von Dantrolen dieser Anstieg inhibiert werden kann. Systemische Effekte müssen allerdings im in-vivo Tierversuch ausgeschlossen werden, um die Mikrodialysetechnik für die Entwicklung eines minimal-invasiven Verfahrens zur Diagnostik der malignen Hyperthermie nutzbar machen zu können. N2 - Malignant hyperthermia (MH) is a metabolic disease of skeletal muscle. An increased calcium release inside the muscle cell leads to muscle contraction and activates cellular metabolism. The In-Vitro Contracture Test of skeletal muscle is the only reliable method to detect MH susceptibility. The aim of the present study was to investigate the effects of calcium and caffeine application through a microdialysis probe and the effects of systemic ryanodine and dantrolene infusion on local lactate metabolism. With approval of the local animal care committee 61 Sprague Dawley rats were anaesthetized, anticoagulated and both hind limbs were perfused through the aorta with ringer-, ryanodine (0,25 µM, 1 µM) or dantrolene (1 µM) solution post mortem (30 ml/h, 21 oC). Through microdialysis-probes both Mm. adductors were perfused by ringer-, sorbitol/ringer (80 mM), calcium/ringer (20 mM, 40 mM, 80 mM) or caffeine/ringer (40 mM, 80 mM) solution with 1 µl/min flow. Lactate was measured spectrophotometrically. The relative recovery of lactate was 77 ± 2%. Microdialysis perfusion of calcium 20 mM, 40 mM and 80 mM respectively increased local lactate concentration to 466 ± 31%, 632 ± 48% and 635 ± 81%. Microdialysis perfusion of caffeine 40 mM and 80 mM increased local lactate levels to 270 ± 21% and 377 ± 21%. The isolated skeletal muscle perfusion with ryanodine 0,25 µM and 1 µM, and synchronous microdialysis application of caffeine 40 mM increased local lactate concentration significantly to 279 ± 23% and 331 ± 19%. In contrast lactate levels increased only to 193 ± 13% during infusion of dantrolene 1 µM and local perfusion of caffeine 40 mM. This study shows, that local perfusion of calcium and caffeine, and systemic perfusion of ryanodine induce local lactate increase, while systemic application of dantrolene inhibits the caffeine-induced increase. Systemic side-effects have to be ruled out in further animal studies in order to use this microdialysis technique with local application of a MH-trigger as a minimally invasive method to diagnose MH susceptibility. KW - Mikrodialyse KW - Maligne Hyperthermie KW - Laktat KW - Skelettmuskel KW - Ratte KW - Microdialysis KW - Malignant Hyperthermia KW - Lactate KW - Skeletal muscle KW - rat Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-4397 ER - TY - JOUR A1 - Schuster, Frank A1 - Johannsen, Stephan A1 - Moegele, Susanne A1 - Metterlein, Thomas A1 - Roewer, Norbert A1 - Anetseder, Martin T1 - The effect of succinylcholine on malignant hyperthermia events in susceptible swine N2 - Background While the impact of volatile anaesthetics to induce malignant hyperthermia (MH) is abundantly clear, the role of succinylcholine still remains controversial. To evaluate the influence of succinylcholine on porcine MH events, the authors investigated the hemodynamic and metabolic responses in MH susceptible (MHS) and non-susceptible (MHN) swine following either succinylcholine or halothane application alone or a combination of both substances. Methods With approval of the local animal care committee 27 MHS and 30 MHN pigs were anaesthetized and mechanically ventilated. Fiberoptic probes for continuous PCO2 measurement were inserted into the femoral vein and the triceps muscle. Group A received succinylcholine 4 mg/kg, group B incremental doses of halothane (0.5, 1.0 vol%) and group C succinylcholine and halothane simultaneously. Vital signs were recorded continuously. Results Prior to drug application measured values did not differ between MHS and MHN. While MHN pigs did not show relevant alterations, succinylcholine, halothane and the combination of both lead to significant hemodynamic and metabolic changes in MHS swine. Conclusions Hemodynamic and metabolic alterations following succinylcholine were similar to halothane in MHS pigs. The combination of both pharmacological agents potentiated the observed effects. According to these results succinylcholine acted as an independent and supportive factor during onset of an MH episode. KW - Malignant hyperthermia KW - Succinylcholine KW - Halothane KW - Swine Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110302 ER - TY - JOUR A1 - Johannsen, Stephan A1 - Schick, Martin A1 - Roewer, Norbert A1 - Schuster, Frank T1 - Microdialysis and ultrasound elastography for monitoring of localized muscular reaction after pharmacological stimulation in rats JF - BMC Research Notes N2 - Objective: Halothane and caffeine are known to cause skeletal muscular contractions in vitro and have been proven to induce circumscribed metabolic reactions when injected into rat skeletal muscle. In this study 26 rats were investigated by either continuous application of calcium 160 mM or bolus injection of caffeine 160 mM or halothane 10% vol via a microdialysis probe in the tibialis anterior muscle. Tissue elasticity at the injection site was monitored by ultrasound strain elastography. Aim of this study was to detect (I) changes in local lactate concentrations and (II) whether these can be attributed to a muscular contraction detected by ultrasound elastography. Results: Localized metabolic reactions were verified by increasing intramuscular lactate concentrations following continuous application of calcium (0.6 [0.3;0.6] to 3.6 [3.0;4.3] mmol/l after 60 min) and bolus application of caffeine (0.2 [0.2;0.3] to 1.6 [0.9;1.9] mmol/l after 30 min) and halothane (0.3 [0.1;0.3] to 4.7 [4.3;6.3] mmol/l after 30 min). However, ultrasound elastography did not detect any differences in tissue elasticity compared to control animals. The authors identified potential limitations of the study conditions, which might be crucial to avoid for future investigations. KW - skeletal muscle KW - ultrasound strain elastography KW - microdialysis KW - halothane KW - caffeine Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176977 VL - 11 IS - 636 ER - TY - JOUR A1 - Schuster, Frank A1 - Johannsen, Stephan A1 - Isbary, Susanne A1 - Türkmeneli, Ismail A1 - Roewer, Norbert T1 - In vitro effects of levosimendan on muscle of malignant hyperthermia susceptible and non-susceptible swine JF - BMC Anesthesiology N2 - Background: The calcium sensitizer levosimendan is increasingly used to improve hemodynamics in patients with acutely decompensated heart failure. By binding to cardiac troponin C the conformation of the calcium-troponin C complex is stabilized, which leads to acceleration of actin-myosin crossbrigde formation and increased force generating capacity of muscle fibers. Besides indications in cardiac failure, beneficial effects of levosimendan in skeletal muscle disorders are currently evaluated. The aim of this study was to investigate differential effects of levosimendan on skeletal muscle of pigs with and without susceptibility to malignant hyperthermia (MH) in order to identify possible risks of this emerging drug for patients with predisposition to MH. Methods: Muscle bundles of 17 pigs (9 MH susceptible (MHS); 8 MH non-susceptible (MHN)) were excised under general anesthesia and examined in the tissue bath with increasing concentrations of levosimendan (0.065; 0.125; 0.5; 1.0; 10 and 50 μg/ml). Baseline tension and twitch force were monitored continuously. Data are presented as median and interquartile range. Statistical evaluation was performed using D’Agostino & Pearson test for normal distribution and student’s t test and 2-way ANOVA for differences between the groups. P < 0.05 was considered significant. Results: There were no differences between the groups concerning length, weight, initial twitch force and pre-drug resting tension of the investigated muscle strips. After an initial decrease in both groups, twitch amplitude was significantly higher in MHN (− 3.0 [− 5.2–0.2] mN) compared to MHS (− 7.5 [− 10.8- -4.5] mN) (p = 0.0034) muscle at an applied levosimendan concentration of 50 μg/ml. A marked increase in resting tension was detected following levosimendan incubation with 50 μg/ml in MHS muscle bundles (3.3 [0.9–6.1] mN) compared to MHN (− 0.7 [− 1.3–0.0] mN) (p < 0.0001). Conclusions: This in vitro investigation revealed the development of significant contractures in muscle bundles of MHS pigs after incubation with levosimendan. However, the effect appeared only at supra-therapeutic concentrations and further research is needed to determine the impact of levosimendan on MHS individuals in vivo. KW - malignant hyperthermia KW - levosimendan KW - muscle KW - pigs KW - in vitro contracture test Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176991 VL - 18 IS - 182 ER - TY - JOUR A1 - Schuster, Frank A1 - Wessig, Carsten A1 - Schimmer, Christoph A1 - Johannsen, Stephan A1 - Lazarus, Marc A1 - Aleksic, Ivan A1 - Leyh, Rainer A1 - Roewer, Norbert T1 - In vitro contracture test results and anaesthetic management of a patient with emery-dreifuss muscular dystrophy for cardiac transplantation JF - Case Reports in Anesthesiology N2 - Emery-Dreifuss muscular dystrophy (EDMD) is a hereditary neuromuscular disorder characterized by slowly progressive muscle weakness, early contractures, and dilated cardiomyopathy. We reported an uneventful general anaesthesia using total intravenous anaesthesia (TIVA) for cardiac transplantation in a 19-year-old woman suffering from EDMD. In vitro contracture test results of two pectoralis major muscle bundles of the patient suggest that exposition to triggering agents does not induce a pathological sarcoplasmic calcium release in the lamin A/C phenotype. However, due to the lack of evidence in the literature, we would recommend TIVA for patients with EDMD if general anaesthesia is required. KW - Emery-Dreifuss muscular dystrophy Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-123413 VL - 2012 IS - 349046 ER - TY - JOUR A1 - Klingler, Werner A1 - Heiderich, Sebastian A1 - Girard, Thierry A1 - Gravino, Elvira A1 - Heffron, James J. A. A1 - Johannsen, Stephan A1 - Jurkat-Rott, Karin A1 - Rüffert, Henrik A1 - Schuster, Frank A1 - Snoeck, Marc A1 - Sorrentino, Vincenzo A1 - Tegazzin, Vincenzo A1 - Lehmann-Horn, Frank T1 - Functional and genetic characterization of clinical malignant hyperthermia crises: a multi-centre study JF - Orphanet Journal of Rare Diseases N2 - Background: Malignant hyperthermia (MH) is a rare pharmacogenetic disorder which is characterized by life-threatening metabolic crises during general anesthesia. Classical triggering substances are volatile anesthetics and succinylcholine (SCh). The molecular basis of MH is excessive release of Ca2+ in skeletal muscle principally by a mutated ryanodine receptor type 1 (RyR1). To identify factors explaining the variable phenotypic presentation and complex pathomechanism, we analyzed proven MH events in terms of clinical course, muscle contracture, genetic factors and pharmocological triggers. Methods: In a multi-centre study including seven European MH units, patients with a history of a clinical MH episode confirmed by susceptible (MHS) or equivocal (MHE) in vitro contracture tests (IVCT) were investigated. A test result is considered to be MHE if the muscle specimens develop pathological contractures in response to only one of the two test substances, halothane or caffeine. Crises were evaluated using a clinical grading scale (CGS), results of IVCT and genetic screening. The effects of SCh and volatile anesthetics on Ca2+ release from sarcoplasmic reticulum (SR) were studied in vitro. Results: A total of 200 patients met the inclusion criteria. Two MH crises (1%) were triggered by SCh (1 MHS, 1 MHE), 18% by volatile anesthetics and 81% by a combination of both. Patients were 70% male and 50% were younger than 12 years old. Overall, CGS was in accord with IVCT results. Crises triggered by enflurane had a significantly higher CGS compared to halothane, isoflurane and sevoflurane. Of the 200 patients, 103 carried RyR1 variants, of which 14 were novel. CGS varied depending on the location of the mutation within the RyR1 gene. In contrast to volatile anesthetics, SCh did not evoke Ca2+ release from isolated rat SR vesicles. Conclusions: An MH event could depend on patient-related risk factors such as male gender, young age and causative RyR1 mutations as well as on the use of drugs lowering the threshold of myoplasmic Ca2+ release. SCh might act as an accelerant by promoting unspecific Ca2+ influx via the sarcolemma and indirect RyR1 activation. Most MH crises develop in response to the combined administration of SCh and volatile anesthetics. KW - susceptibility KW - central core disease KW - skeletal muscle KW - North American KW - malignant hyperthermia KW - succinylcholine KW - suxamethonium KW - volatile anesthetics KW - RyR1 mutations KW - New Zealand KW - inhalation anesthetics KW - sarcoplasmic reticulum KW - ryanodine receptor gene KW - vitro contracture test Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117630 SN - 1750-1172 VL - 9 IS - 8 ER - TY - JOUR A1 - Schuster, Frank A1 - Johannsen, Stephan A1 - Schneiderbanger, Daniel A1 - Roewer, Norbert T1 - Evaluation of suspected malignant hyperthermia events during anesthesia JF - BMC Anesthesiology N2 - Background Malignant hyperthermia (MH), a metabolic myopathy triggered by volatile anesthetics and depolarizing muscle relaxants, is a potentially lethal complication of general anesthesia in susceptible patients. The implementation of modern inhalation anesthetics that research indicates as less potent trigger substances and the recommended limitations of succinylcholine use, suggests there may be considerable decline of fulminant MH cases. In the presented study, the authors analyzed suspected MH episodes during general anesthesia of patients that were referred to the Wuerzburg MH unit between 2007 and 2011, assuming that MH is still a relevant anesthetic problem in our days. Methods With approval of the local ethics committee data of patients that underwent muscle biopsy and in vitro contracture test (IVCT) between 2007 and 2011 were analyzed. Only patients with a history of suspected MH crisis were included in the study. The incidents were evaluated retrospectively using anesthetic documentation and medical records. Results Between 2007 and 2011 a total of 124 patients were tested. 19 of them were referred because of suspected MH events; 7 patients were diagnosed MH-susceptible, 4 MH-equivocal and 8 MH-non-susceptible by IVCT. In a majority of cases masseter spasm after succinylcholine had been the primary symptom. Cardiac arrhythmias and hypercapnia frequently occurred early in the course of events. Interestingly, dantrolene treatment was initiated in a few cases only. Conclusions MH is still an important anesthetic complication. Every anesthetist must be aware of this life-threatening syndrome at any time. The rapid onset of adequate therapy is crucial to avoid major harm and possibly lethal outcome. Dantrolene must be readily available wherever MH triggering agents are used for anesthesia. KW - Malignant hyperthermia KW - In vitro contracture test KW - Succinylcholine KW - Volatile anesthetics Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96231 UR - http://www.biomedcentral.com/1471-2253/13/24 ER - TY - JOUR A1 - Schuster, Frank A1 - Johannsen, Stephan A1 - Roewer, Norbert T1 - A Minimal-Invasive Metabolic Test Detects Malignant Hyperthermia Susceptibility in a Patient after Sevoflurane-Induced Metabolic Crisis JF - Case Reports in Anesthesiology N2 - Malignant hyperthermia is a rare but life-threatening complication of general anesthesia in predisposed patients usually triggered by potent inhalation anesthetics and/or the depolarizing muscle relaxant succinylcholine. The authors present a case of delayed sevoflurane-induced malignant hyperthermia in a 21-year-old male patient that was sufficiently treated by discontinuation of trigger agent application and dantrolene infusion. After surviving an MH episode diagnostic procedures are indicated to increase patient safety. In the presented case, the use of a novel minimal-invasive metabolic test with intramuscular injection of halothane and caffeine successfully confirmed MH susceptibility and hence might be an alternative for invasive in vitro contracture testing in selected cases. KW - Medizin Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97080 ER -