Comparison of the caffeine skinned fibre tension (csft) test with the caffeine-halothane contracture (chc) test in the diagnosis of malignant hyperthermia

Abstract

We have compared and contrasted two diagnostic tests for Malignant Hyperthermia (MH) -the Caffeine-Halothane Contracture Test and the Caffeine Skinned Fibre Tension Test. Both tests show a strongly positive relationship both with the occurrence of MH reactions and with each other. The former test is more rapid and requires less skill. The latter test can be performed on much less muscle and permits storage of the muscle over prolonged periods of time. of muscle required was small. Moreover, fibres prepared from muscle stored for several months in the freezer were still viable. We felt, therefore, that a diagnostic test for MH based on this preparation might have several advantages over the CHC test of intact muscle fascicles. Much less muscle would be needed. Experimental errors could be rectified by another trip to the freezer. Considerable information might be learned about the site and nature of the MH defect,In 1977, therefore, during the course of routine biopsies in suspected MH patients, in addition to obtaining muscle for our usual diagnostic tests (CHC test, 2'3 halothane-ATP depletion test (H-ATP-D), 3 and routine microscopyZ), we also excised small strips of muscle secured to wooden sticks. These were chemically skinned by the method of Wood z2-2s and were then sent to him by private courier for examination. Wood found that in malignant hyperthermic susceptible (MHS) muscle a larger than normal percentage of fibres developed tensions at lower than normal caffeine concentrations. 25 Because of these promising preliminary findings we decided to examine in detail in our own laboratory the value of this technique as a sole diagnostic test, as a complement to the CHC test and as an aid in learning more about the nature of the MH defect. The test has now been named the caffeine skinned fibre tension (CSFr) test. 550

Myopathy caused by a deficiency of Ca2+‐adenosine triphosphatase in sarcoplasmic reticulum (Brody's disease)

“…If the relevant target of caffeine action is the Ca2 +-ATPase [ 3 3 ] , it is possible that on account of the deficiency of this enzyme in type 2 fibers, the excessive caffeine sensitivity is attributable to type 1 fibers, which are known to be more sensitive to caffeine [ 3 ] . Since an , abnormally low caffeine-specific concentration in an in vitro contracture test usually correlates with predisposition to malignant hyperthermia reaction [2], appropriate anesthetic precautions appear to be advisable in Brody's disease.…”

Comparison of the in vitro caffeine-halothane contracture test with the Ca-induced Ca release rate test in patients suspected of having malignant hyperthermia susceptibility

“…However, when the new version of the cutoff point (Ͼ0.5 g at 3% halothane, Ͼ0.3 g at 2 mM caffeine in the NAMHG protocol) was applied to our results, the accordance rate between the two CHCTs decreased to 83%. Several types of skinned-fiber tests for diagnosis of MH have been reported [19,20]. This is the test to determine the sensitivity of skinned fibers for contracture obtained by caffeine or halothane according to the same principle used to measure the threshold of contracture in CHCT.…”

“…This is the test to determine the sensitivity of skinned fibers for contracture obtained by caffeine or halothane according to the same principle used to measure the threshold of contracture in CHCT. One comparative study showed that the caffeine skinned fiber tension test showed a strongly positive relationship with CHCT, and the authors concluded that this test could be used as a complement test because of a decrease in the required sample size and a longer possible time period from biopsy to test, but not that the test could be used as a substitute for CHCT [19]. Using 50% glycerol-EGTA pretreated skinned fibers, Adnet et al showed a significantly higher sensitivity to caffeine in type I fibers (slow-twitch, slow oxidative) than in type II fibers (fast-twitch, fast glycolytic) from MHS and MH nonsusceptible patients [21].…”

Use of the Calcium Agonist Bay K 8644 for in Vitro Diagnosis of Susceptibility to Malignant Hyperthermia

“…Tests involving simultaneous exposure to both halothane and caffeine produce data which overlap between normal and known MHS patients [3]. Takagi and colleagues [12] have suggested the use of a single skinned muscle fibre test which seems to correlate with the muscle bundle test [13]. However, this method is difficult to perform and time consuming.…”