Screening test for malignant hyperthermia in patients with persistent hyperCKemia: a pilot study

Use of clinical chemistry health outcomes and PFAS chain length to predict 28-day rodent oral toxicity

Current literature suggests PFAS carbon chain length may be a predictive variable of toxicity. If so, statistical modeling may be used to help predict toxicity, thus improving the efficiency of PFAS regulation development. Data were analyzed using one-way ANOVAs, Tukey's HSD post hoc tests, and simple linear regressions. A dataset was predicted using modeling from this data. Analysis indicated that 11 of 15 health outcomes showed significant differences in mean values. Two of 15 health outcomes were analyzed using simple linear regressions, with statistically significant results. After predictive modeling generated a theoretical dataset, unpaired t-tests comparing the results of an actual dataset indicated no significant differences among the mean values of the two health outcomes. Therefore, predictive statistical modeling may be used to predict health outcomes for PFAS exposure.

Creatine metabolism: energy homeostasis, immunity and cancer biology

Perturbations in metabolic processes are associated with diseases such as obesity, type 2 diabetes mellitus, certain infections and some cancers. A resurgence of interest in creatine biology is developing, with new insights into a diverse set of regulatory functions for creatine. This resurgence is primarily driven by technological advances in genetic engineering and metabolism as well as by the realization that this metabolite has key roles in cells beyond the muscle and brain. Herein, we highlight the latest advances in creatine biology in tissues and cell types that have historically received little attention in the field. In adipose tissue, creatine controls thermogenic respiration and loss of this metabolite impairs whole-body energy expenditure, leading to obesity. We also cover the various roles that creatine metabolism has in cancer cell survival and the function of the immune system. Renewed interest in this area has begun to showcase the therapeutic potential that lies in understanding how changes in creatine metabolism lead to metabolic disease.

The current status of malignant hyperthermia

Malignant hyperthermia (MH) is a rare and life-threatening pharmacogenetic disorder triggered by volatile anesthetics, the depolarizing muscle relaxant succinylcholine, and rarely by strenuous exercise or environmental heat. The exact prevalence of MH is unknown, and it varies from 1:16 000 in Denmark to 1:100 000 in New York State. The underlying mechanism of MH is excessive calcium release from the sarcoplasmic reticulum (SR), leading to uncontrolled skeletal muscle hyper-metabolism. Genetic mutations in ryanodine receptor type 1 ( RYR1) and CACNA1S have been identified in approximately 50% to 86% and 1% of MH-susceptible (MHS) individuals, respectively. Classic clinical symptoms of MH include hypercarbia, sinus tachycardia, masseter spasm, hyperthermia, acidosis, muscle rigidity, hyperkalemia, myoglobinuria, and etc. There are two types of testing for MH: a genetic test and a contracture test. Contracture testing is still being considered as the gold standard for MH diagnosis. Dantrolene is the only available drug approved for the treatment of MH through suppressing the calcium release from SR. Since clinical symptoms of MH are highly variable, it can be difficult to establish a diagnosis of MH. Nevertheless, prompt diagnosis and treatments are crucial to avoid a fatal outcome. Therefore, it is very important for anesthesiologists to raise awareness and understand the characteristics of MH. This review summarizes epidemiology, clinical symptoms, diagnosis and treatments of MH and any new developments.

Label-free SERS diagnostics of radiation-induced injury via detecting the biomarker Raman signal in the serum and urine bio-samples based on Au-NPs array substrates

A sensitive approach based on surface enhanced Raman spectroscopy (SERS) has been developed to evaluate the radiation caused biological injury. To achieve the effective SERS substrate, canonical anodic aluminum oxide (AAO) templates with regular array of nanotips were fabricated, and by plasma sputtering the gold nanoparticles (Au-NPs) were distributed on the nanotips to form the Au-NPs array with plenty of hotspots. The SERS substrates were utilized to examine the serum samples taken from the mice with the treatment of total body irradiation (TBI) of X-ray. The impact of TBI on the mice was analyzed and it was found that the SERS peak intensity at 532 cm^-1 increased as a function of duration or dose of TBI. We confirmed that this Raman signature belongs to the myoglobin as a biomarker for the muscle damage due to the radiation caused injury. Furthermore, we also tested several blood and urine specimen of cancer patients who received radiotherapy. The results showed that our approach to some extent could distinguish the bio-samples from normal, X-ray treated and untreated individuals. Therefore, the proposed methodology may have the potential for prompt prognosis of radiation injury at early stage.

Ultrasound Elastography for Rapid, Real-time Detection of Localized Muscular Reaction in Malignant Hyperthermia-susceptible Pigs

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Halothane and caffeine induce excessive sarcoplasmic calcium liberation and skeletal muscle contracture in patients susceptible to malignant hyperthermia (MH) and are utilized for diagnosis in the in vitro contracture test. Intramuscular injection previously caused a marked local lactate increase in MH-susceptible but not in MH-nonsusceptible individuals in vivo. Using shear-wave elastography, this study evaluated localized changes in muscle stiffness after intramuscular injection of halothane and caffeine.

METHODS

Microdialysis probes were placed into the gracilis muscle of 16 pigs (9 MH-susceptible and 7 MH-nonsusceptible). After local injection of either halothane or caffeine in different concentrations, changes of tissue elasticity surrounding the probe were examined by quantitative shear-wave elastography. Local lactate concentrations were analyzed spectrophotometrically.

RESULTS

Ultrasound elastography detected a temporary increase in local muscle rigidity in MH-susceptible but not in MH-nonsusceptible pigs after 2.5 and 5 vol% halothane and after 10, 40, and 80 mM caffeine, whereas there were no differences in the control groups (median [interquartile range] for maximum effect after 5 vol% halothane: MH-susceptible: 97 [31 to 148] vs. MH-nonsusceptible: 5 [-6 to 18] kPa; P = 0.0006; maximum effect after 80 mM caffeine: 112 [64 to 174] vs. -3 [-6 to 35] kPa; P = 0.0002). These effects were seen rapidly within 5 min. Local lactate concentrations were higher in MH-susceptible versus nonsusceptible pigs after 1 and 2.5 vol% halothane and 10, 40, and 80 mM caffeine (2.5 vol% halothane: MH-susceptible: 2.8 [1.9 to 4.4] vs. MH-nonsusceptible: 0.6 [0.6 to 0.7] mmol/l; P < 0.0001; 80 mM caffeine: 5.2 [4.1 to 6.3] vs. 1.6 [1.2 to 2.4] mmol/l; P < 0.0001). After 10 vol% halothane, rigidity and lactate levels were increased in both MH-susceptible and MH-nonsusceptible animals.

CONCLUSIONS

This pilot study revealed shear-wave elastography as a suitable technique for real-time detection of altered tissue elasticity in response to pharmacologic stimulation. By considering the variability of these results, further test protocol optimization is required before elastography could serve as a minimally invasive MH diagnostic test.

Postoperative changes in serum creatine kinase in paediatric orthopaedic patients with preoperative hyperCKaemia: review of three cases

An elevated serum creatine kinase (CK) level is commonly known as hyperCKaemia, and anaesthesiologists must take into account the potential susceptibility of hyperCKaemia patients to develop malignant hyperthermia during general anaesthesia as well as acute onset of rhabdomyolysis postoperatively. Three paediatric patients with hyperCKaemia were scheduled for orthopaedic surgery. With the consent of their parents, their CK changes were monitored for seven days postoperatively to detect rhabdomyolysis. The results showed that the postoperative CK change patterns were almost the same as those for patients whose CK levels were within reference range. Maximum CK levels tended to be higher in these patients than in the CK reference-range patients studied previously, although the reason remains unclear. This experience and previous studies suggest that measuring CK levels at least on postoperative days 1 and 2 might be better for detecting early signs of rhabdomyolysis, even in paediatric patients with hyperCKaemia.

[Telephone enquiries on the topic of malignant hyperthermia: Evaluation of the content and subsequent diagnostic results at the MH Center Leipzig]

BACKGROUND

Malignant hyperthermia (MH) is an autosomal dominant metabolic myopathy. The in vitro contracture test (IVCT) is still considered to be the gold standard for diagnosing a disposition for MH. However, advances in genetic testing for MH disposition have supplemented or even replaced the invasive procedure of the IVCT. Information about MH can be obtained by either contacting the hotline for MH as a nationwide 24 h/7 days a week service or one of the regional MH centers.

METHODS

The protocols of telephone conversations concerning MH at the MH Center University Leipzig were retrospectively analyzed. Data were collected from January 2011 to March 2015. Additionally, the results of the IVCT and genetic testing evolving from the counseling interviews were examined.

RESULTS

A total of 205 telephone calls were documented during the period in question and an IVCT was performed as a consequence of 112 of the telephone calls. The IVCT resulted in 27 individuals being identified as MH susceptible which was subsequently diagnosed in 15 individuals with known familial MH disposition and 12 individuals were identified as new index patients. In 24 individuals a total of 13 different mutations were detected and of these 4 mutations were causative concerning MH. Of the 205 telephone calls 131 were private and 74 of medical professional origin. Among the private enquiries MH disposition within the family was a frequent reason for contacting the MH Center (61.8%). Conversations relating to MH-like symptoms during general anesthesia were carried out with 35.1% of medical doctors and with 22.9% of private callers. Advice about neuromuscular symptoms of unknown genesis was given to 15.3% of private individuals and to 24.3% of medical doctors. Overall MH topics were discussed with 23% (N = 17) of the medical profession and approximately half of these were anesthesiologists (N = 8). Not a single call was documented for the treatment of a suspected MH crisis.

CONCLUSION

Private individuals and families affected by a MH disposition often showed good compliance with respect to counseling and diagnostics for MH and contacted the MH center more often than medical doctors. A more comprehensive cooperation with the medical profession is preferable and necessary to obtain a systematic and broad synopsis of characteristic and uncharacteristic signs and symptoms of MH. The telephone conversations analyzed as well as the diagnostic results (IVCT and genetic testing) underline that MH disposition is still a current and relevant topic.

Malignant hyperthermia, a Scandinavian update

BACKGROUND

Malignant Hyperthermia (MH) is a rare pharmacogenetic disorder, triggered by halogenated anesthetics and/or succinylcholine. In susceptible individuals, these drugs can activate an explosive life threatening clinical reaction. Leading symptoms are hypercarbia, muscle rigidity, and metabolic acidosis. MH is inherited in an autosomal-dominant manner and linked to mutations in the large ryanodine 1 gene (RYR1) gene in the majority of cases. Very few MH patients have been found to carry mutations in the CACNA1S gene.

METHODS

For this review a large litterature search was carried out and the Swedish MH database consisting of 436 probands who have undergone in vitro muscle contraction test (IVCT) during 1984-2014 was analyzed.

RESULTS

Twelve different MH causative mutations have been found in Swedish patients so far. These mutations lead to a disturbed calcium balance in striated muscle tissue. A muscle biopsy for the IVCT or finding of an approved causative mutation are required for the diagnosis.

CONCLUSION

A Malignant Hyperthermia susceptible (MHS) patient should be anesthetized with trigger-free anesthesia. There are a few reports of MH-like reactions in patients unrelated to anesthesia. The outcome is dependent on early recognizing of the reaction and fast disconnection of the trigger agents and administration of dantrolene.