European Malignant Hyperthermia Group guidelines for investigation of malignant hyperthermia susceptibility.

It is 30 yr since the British Journal of Anaesthesia published the first consensus protocol for the laboratory diagnosis of malignant hyperthermia susceptibility from the European Malignant Hyperthermia Group. This has subsequently been used in more than 10 000 individuals worldwide to inform use of anaesthetic drugs in these patients with increased risk of developing malignant hyperthermia during general anaesthesia, representing an early and successful example of stratified medicine. In 2001, our group also published a guideline for the use of DNA-based screening of malignant hyperthermia susceptibility. We now present an updated and complete guideline for the diagnostic pathway for patients potentially at increased risk of developing malignant hyperthermia. We introduce the new guideline with a narrative commentary that describes its development, the changes to previously published protocols and guidelines, and new sections, including recommendations for patient referral criteria and clinical interpretation of laboratory findings.

Recognizing and managing a malignant hyperthermia crisis: guidelines from the European Malignant Hyperthermia Group.

Survival from a malignant hyperthermia (MH) crisis is highly dependent on early recognition and prompt action. MH crises are very rare and an increasing use of total i.v. anaesthesia is likely to make it even rarer, leading to the potential risk of reduced awareness of MH. In addition, dantrolene, the cornerstone of successful MH treatment, is unavailable in large areas around the world thereby increasing the risk of MH fatalities in these areas. The European Malignant Hyperthermia Group collected and reviewed all guidelines available from the various MH centres in order to provide a consensus document. The guidelines consist of two textboxes: Box 1 on recognizing MH and Box 2 on the treatment of an MH crisis.

Effect of maca supplementation on bovine sperm quantity and quality followed over two spermatogenic cycles.

Maca (Lepidium meyenii Walpers), is an Andean crop that grows between 3,800 and 4,500 m a.s.l. The persistent interest in this plant is based on its assumed effects on fertility of male mammals due to the prevalence of certain, partially specific, secondary compounds. The present study aimed at evaluating the effect of maca supplementation on quality and quantity of semen, mating behavior, and clinical status of peripubertal breeding bulls. The experiment followed a cross-over design lasting for 23 wk with 3 wk of adaptation and baseline measurements, and 2 x 10 wk of treatment feeding thus covering two times the complete 8-wk spermatogenic cycle. Seventy-eight 55 wk to 84 wk old breeding bulls received either no maca (control) or maca (233 mg dried hypocotyls/kg body weight/day) for 10 wk followed by 10 wk without maca (maca early) or maca only in the last 10 wk (maca late). Measurements were always made in the last 2 wk of each period. Apart from standard analyses, ejaculates were analyzed by flow cytometry. Data was evaluated by analysis of variance considering the repeated measurement structure of the data. Significant treatment by measurement period indicated direct or carry-over effects of maca. Maca supplementation had no direct effect on body weight, testes circumference, rectal temperature, mating behavior, and ejaculate volume. However, supplementing maca in the first 10 wk period increased the number of sperms in the second 10 wk period, i.e., when the animals no longer received maca. The DNA fragmentation index and the visually assessed motility of the sperms of bulls, that initially showed a borderline sperm quality, were significantly improved with early maca supplementation, while no such effect was observed in the two other groups. No effects occurred in the proportion of intact sperm plasma membranes or acrosomes or both. In conclusion, maca supplementation seems to improve sperm quantity and quality of bulls to a certain degree, while mating behavior appears unaffected.

Adult behavioral and pharmacological dysfunctions following disruption of the fetal brain balance between pro-inflammatory and IL-10-mediated anti-inflammatory signaling.

Maternal infections during pregnancy increase the risk for schizophrenia and related disorders of putative neurodevelopmental origin in the offspring. This association has been attributed to enhanced expression of pro-inflammatory cytokines in the fetal environment in response to maternal immunological stimulation. In contrast, the specific roles of anti-inflammatory cytokines are virtually unknown in this context. Here, we demonstrate that genetically enforced expression of the anti-inflammatory cytokine interleukin (IL)-10 by macrophages attenuates the long-term behavioral and pharmacological consequences of prenatal immune activation in a mouse model of prenatal viral-like infection by polyriboinosinic-polyribocytidilic acid (PolyI:C; 2 mg/kg, intravenously). In the absence of a discrete prenatal inflammatory stimulus, however, enhanced levels of IL-10 at the maternal-fetal interface by itself also precipitates specific behavioral abnormalities in the grown offspring. This highlights that in addition to the disruptive effects of excess pro-inflammatory molecules, a shift toward enhanced anti-inflammatory signaling in prenatal life can similarly affect cognitive and behavioral development. Hence, shifts of the balance between pro- and anti-inflammatory cytokine classes may be a critical determinant of the final impact on neurodevelopment following early life infection or innate immune imbalances.

Fulminant neuroleptic malignant syndrome after perioperative withdrawal of antiParkinsonian medication.

Neuroleptic malignant syndrome is a rare complication when using neuroleptic drugs. We report the case of a patient with severe Parkinson's disease who developed neuroleptic malignant syndrome after withdrawal of his antiParkinsonian medication for elective coronary artery bypass grafting. Sodium dantrolene may be a therapeutic option in severe cases.

Similar susceptibility to halothane, caffeine and ryanodine in vitro reflects pharmacogenetic variability of malignant hyperthermia.

BACKGROUND AND OBJECTIVE: To analyse the use of standardized application of ryanodine for in vitro muscle contracture testing to define cut-off values separating malignant hyperthermia susceptible from malignant hyperthermia negative subjects. Furthermore, we compared the results of in vitro muscle-contracture tests following the halothane, caffeine and ryanodine challenges. METHODS: In 113 subjects, halothane, caffeine and ryanodine muscle-contracture tests were performed according to the protocol of the European Malignant Hyperthermia Group. RESULTS: Malignant hyperthermia susceptible subjects (n = 77) had significantly shorter onset times in the ryanodine in vitro muscle-contracture test (1 micromol ryanodine) compared with malignant hyperthermia negative subjects (n = 36), median 4.8 vs. 20.1 min, respectively, without any influence of age or gender. The best cut-off value was 10 min (sensitivity 0.78 and specificity 0.94, respectively). Shorter cut-off values had greater specificity, but lower sensitivity. Groups could not be separated without an overlap. In susceptible subjects, we found a correlation between onset time and threshold concentrations for halothane and caffeine (p = 0.47 and 0.52, respectively). In addition, muscle bundles with high susceptibility to halothane and caffeine also showed high susceptibility to ryanodine. CONCLUSIONS: The ryanodine in vitro muscle-contracture test confirmed the malignant hyperthermia status that was determined using the halothane and caffeine in vitro muscle-contracture tests. Due to an overlap between the two groups, discrimination ability was not always perfect and short cut-off values with higher specificity had reduced sensitivity and vice versa. The correlation of contractures following the halothane, caffeine and ryanodine challenges points towards a similar individual pharmacogenetic effect rather than a specific, different pharmacological action between the three agents.

Effect of three anaesthetic techniques on isometric skeletal muscle strength.

BACKGROUND: Our aim was to quantify human involuntary isometric skeletal muscle strength during anaesthesia with propofol, sevoflurane, or spinal anaesthesia using bupivacaine. METHODS: Thirty-three healthy patients undergoing anaesthesia for elective lower limb surgery were investigated. Twenty-two patients received a general anaesthetic with either propofol (n=12) or sevoflurane (n=10); for the remaining 11 patients spinal anaesthesia with bupivacaine was used. We used a non-invasive muscle force assessment system before and during anaesthesia to determine the contractile properties of the ankle dorsiflexor muscles after peroneal nerve stimulation (single, double, triple, and quadruple stimulation). We measured peak torques; contraction times; peak rates of torque development and decay; times to peak torque development and decay; half-relaxation times; torque latencies. RESULTS: Males elicited greater peak torques than females, medians 6.3 vs 4.4 Nm, respectively (P=0.0002, Mann-Whitney rank-sum test). During sevoflurane and propofol anaesthesia, muscle strength did not differ from pre-anaesthetic values. During spinal anaesthesia, torques were diminished for single-pulse stimulation from 3.5 to 2.0 Nm (P=0.002, Wilcoxon signed rank test), and for double-pulse from 7.6 to 5.6 Nm (P=0.02). Peak rates of torque development decreased for single-pulse stimulation from 113 to 53 Nm s(-1) and for double pulse from 195 to 105 Nm s(-1). Torque latencies were increased during spinal anaesthesia. CONCLUSIONS: At clinically relevant concentrations, propofol and sevoflurane did not influence involuntary isometric skeletal muscle strength in adults, whereas spinal anaesthesia reduced strength by about 20%. Muscle strength assessment using a device such as described here provided reliable results and should be considered for use in other scientific investigations to identify potential effects of anaesthetic agents.

Multicentre evaluation of in vitro contracture testing with bolus administration of 4-chloro-m-cresol for diagnosis of malignant hyperthermia susceptibility.

BACKGROUND AND OBJECTIVE: The in vitro contracture test with halothane and caffeine is the gold standard for the diagnosis of susceptibility to malignant hyperthermia (MH). However, the sensitivity of the in vitro contracture test is between 97 and 99% and its specificity is 78-94% with the consequence that false-negative as well as false-positive test results are possible. 4-Chloro-m-cresol is potentially a more specific test drug for the in vitro contracture test than halothane or caffeine. This multicentre study was designed to investigate whether an in vitro contracture test with bolus administration of 4-chloro-m-cresol can improve the accuracy of the diagnosis of susceptibility to MH. METHODS: Three hundred and fifty-two patients from 11 European MH laboratories participated in the study. The patients were first classified as MH susceptible, MH normal or MH equivocal by the in vitro contracture test according to the European MH protocol. Muscle specimens surplus to diagnostic requirements were used in this study (MH susceptible = 103 viable samples; MH equivocal = 51; MH normal = 204). 4-Chloro-m-cresol was added to achieve a concentration of 75 micromol L(-1) in the tissue bath. The in vitro effects on contracture development and muscle twitch were observed for 60 min. RESULTS: After bolus administration of 4-chloro-m-cresol, 75 micromol L(-1), 99 of 103 MH-susceptible specimens developed marked muscle contractures. In contrast, only two of 204 MH-normal specimens showed an insignificant contracture development following 4-chloro-m-cresol. From these results, a sensitivity rate of 96.1% and a specificity rate of 99.0% can be calculated for the in vitro contracture test with bolus administration of 4-chloro-m-cresol 75 micromol L(-1). Forty-three patients were diagnosed as MH equivocal, but only specimens from 16 patients developed contractures in response to 4-chloro-m-cresol, indicating susceptibility to MH. CONCLUSIONS: The in vitro contracture test with halothane and caffeine is well standardized in the European and North American test protocols. However, this conventional test method is associated with the risk of false test results. Therefore, an improvement in the diagnosis of MH is needed. Regarding the results from this multicentre study, the use of 4-chloro-m-cresol could increase the reliability of in vitro contracture testing.

Phenotyping malignant hyperthermia susceptibility by measuring halothane-induced changes in myoplasmic calcium concentration in cultured human skeletal muscle cells.

BACKGROUND: Malignant hyperthermia (MH) is a potentially lethal disease triggered by volatile anaesthetics and succinylcholine in genetically predisposed individuals. Because of the heterogenetic nature of MH, a simple genetic-based diagnostic test is not feasible and diagnosis requires an invasive open muscle biopsy followed by the in vitro contracture test (IVCT). Our aim was to establish if measurements of halothane-induced increases in intracellular calcium ion concentration [Ca(2+)](i) in cultured human skeletal muscle cells can be used to phenotype MH susceptibility and if different mutations in the ryanodine receptor (RYR1) gene affect halothane-induced increases in [Ca(2+)](i). METHODS: Primary cultures of human skeletal muscle cells were established from 54 individuals diagnosed by the IVCT according to the protocol of the European MH Group as: MH susceptible (n=22), MH negative (n=18) or MH equivocal (n=14). All individuals were screened for the presence of the most common mutations in the RYR1 gene. [Ca(2+)](i) was measured by fluorescent digital microscopy using fura-2/AM in 10 cells from each patient at five different halothane concentrations. RESULTS: The halothane-induced increase in [Ca(2+)](i) differed significantly between the three diagnostic groups. Different mutations of the RYR1 gene did not have a specific impact on halothane-induced increases in [Ca(2+)](i). CONCLUSIONS: Measurements of [Ca(2+)](i) in human skeletal muscle cells can be used to phenotype MH susceptibility; however, we did not observe a specific effect of any mutation in the RYR1 gene on the halothane-induced increase in [Ca(2+)](i).

[The hereditary motor-sensory neuropathy Charcot-Marie-Tooth disease: anesthesiologic management--case report with literature review]. / Die hereditäre motorischsensible Neuropathie: Charcot-Marie-Tooth-Erkrankung. Anästhesiologisches Management--ein Fallbericht und eine Literaturübersicht.

A 53-year-old woman diagnosed as having hereditary motor-sensory neuropathy Charcot-Marie-Tooth (CMT) disease Type 2, underwent inguinal hernia surgery. In this patient CMT disease was manifested as distal muscle weakness and wasting. Anaesthetic experience with patients who have CMT disease is limited. Association to malignant hyperthermia is very unlikely although there is one case report that shows that there could be a relationship. We describe a total intravenous anaesthesia (TIVA) protocol with propofol and alfentanil without any muscle relaxants after fiberoptic intubation. The patient made an uneventful recovery and was discharged from the hospital on the fourth postoperative day. TIVA was a safe technique in this patient and should be considered as an alternative for patients presenting with CMT disease.

B-lymphocytes from malignant hyperthermia-susceptible patients have an increased sensitivity to skeletal muscle ryanodine receptor activators.

Malignant hyperthermia (MH) is a pharmacogenetic disease triggered by volatile anesthetics and succinylcholine in genetically predisposed individuals. The underlying feature of MH is a hypersensitivity of the calcium release machinery of the sarcoplasmic reticulum, and in many cases this is a result of point mutations in the skeletal muscle ryanodine receptor calcium release channel (RYR1). RYR1 is mainly expressed in skeletal muscle, but a recent report demonstrated the existence of this isoform in human B-lymphocytes. As B-cells can produce a number of cytokines, including endogenous pyrogens, we investigated whether some of the symptoms seen during MH could be related to the involvement of the immune system. Our results show that (i) Epstein-Barr virus-immortalized B-cells from MH-susceptible individuals carrying the V2168M RYR1 gene mutation were more sensitive to the RYR activator 4-chloro-m-cresol and (ii) their peripheral blood leukocytes produce more interleukin (IL)-1beta after treatment with the RYR activators caffeine and 4-chloro-m-cresol, compared with cells from healthy controls. Our result demonstrate that RYR1-mediated calcium signaling is involved in release of IL-1beta from B-lymphocytes and suggest that some of the symptoms seen during an MH episode may be due to IL-1beta production.

Genotype-phenotype comparison of the Swiss malignant hyperthermia population.

Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease, triggered by inhalative anesthetics or depolarizing muscle relaxants in genetically predisposed individuals. Linkage analysis have revealed MH to be a heterogenetic disease with about 50% of MH families linked to the locus of the ryanodine receptor calcium channel (RYR1). We investigated the frequency of the 23 published MH linked RYR1 gene mutations in the Swiss MH population and compared our findings to the results of the in vitro contracture test (IVCT). IVCT was performed following the protocol of the European MH Group and mutation screening was done by PCR amplification of genomic DNA followed by restriction enzyme digestion or SSCP. We identified RYR1 gene mutations in 40% of unrelated MH families (19/48) with a high incidence of the mutation V2168M (27%). IVCT results revealed a significantly stronger functional effect of mutations R614C and V2168M as compared to mutations G2434R and R2458C. This is the first time that such a high incidence of RYR1 gene mutations in an MH population has been found, supporting the use of molecular genetic testing for the diagnosis of MH susceptibility in suitable families. In addition our data show that different RYR1 gene mutations are associated with different IVCT phenotypes.

Guidelines for molecular genetic detection of susceptibility to malignant hyperthermia.

Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disease triggered by several anaesthetic agents. The in vitro muscle contracture test (IVCT) is the standard test to establish an individual's risk of susceptibility to MH. Clinical practitioners and geneticists of the European MH Group have agreed on the present guidelines for the detection of MH susceptibility using molecular genetic techniques and/or IVCT to predict the risk of MH.

In vivo whole-body resting energy expenditure and insulin action in human malignant hyperthermia.

BACKGROUND: Malignant hyperthermia (MH) is a pharmacogenetic disease triggered by volatile anesthetics or succinylcholine. The disorder is heterogenetic and caused by abnormal calcium regulation within skeletal muscle cells. No clear metabolic differences have been found in MH-susceptible (MHS) persons in vivo while not having MH episodes, but some reported signs suggest that insulin action and energy turnover might be altered in muscle of MHS persons. METHODS: In fasting and insulin-stimulated conditions, using the glucose clamp technique and indirect calorimetry, we assessed in vivo resting energy expenditure (REE) and nutrient utilization rates in 10 MHS, 5 MH-equivocal (MHE) and 10 MH-negative (MHN) persons from 14 families. With a model using the persons' fat-free mass, fat mass, age, and gender, we calculated their predicted REE and compared it with measured REE in 10 MHS and 10 MHN persons (measured - predicted = residual REE). RESULTS: In vivo measured REE and glucose disposal rates were similar in 10 MHS and 10 MHN persons. Only during insulin stimulation was residual REE greater in MHS persons (6.4%; P = 0. 013). CONCLUSIONS: In vivo insulin action is unimpaired in MHS persons. Although the absolute values of whole-body REE are the same in MHS and MHN persons, the part of REE independent of the determinants fat-free mass, fat mass, age, and gender is moderately greater in MHS than in MHN persons during insulin exposure. This suggests that MH susceptibility might influence insulin-stimulated energy turnover in muscle.