Anesthesiology
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Case Reports
Genetic effects on the variability of the halothane and caffeine muscle contracture tests.
The spectrum of the clinical presentation of malignant hyperthermia (MH) and the results of recent linkage studies suggest that there is a degree of heterogeneity in MH susceptibility. In the current study, we analyzed in vitro muscle contracture tests from members of large families with MH to evaluate if the results of these tests could be related to genetic influences. ⋯ The differences of in vitro muscle contracture tests among several families with MH provide evidence for genetic influences on the variability of this test procedure. However, it is not known if the observed differences are caused by heterogeneity of the MH gene mutation(s) or by other genetic factors that might modify muscle contractures in vitro.
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Local anesthetics are known to inhibit the voltage-gated sodium current (INa) of the nerve membrane, but it has not been fully studied whether anesthetic concentrations of local anesthetics depress the voltage-gated calcium current (ICa) of mammalian neurons. The effects of local anesthetics on ICa evoked in cultured rat dorsal root ganglion cells were studied. ⋯ These results suggest that both HVA-ICa and LVA-ICa are depressed by tetracaine used at the concentrations required for spinal anesthesia and that the L-type Ca2+ channel among Ca2+ channel subtypes is the most susceptible to tetracaine. A good correlation between local anesthetic potencies to inhibit HVA-ICa and their anesthetic potencies implies that the inhibition of calcium influx through voltage-gated channels may contribute to spinal anesthetic mechanisms.
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Letter Case Reports
Tongue cyanosis after laryngeal mask airway insertion.