An In Silico Investigation of the Molecular Interactions between Volatile Anesthetics and Actin

Volatile anesthetics (VAs) are medicinal chemistry compounds commonly used to enable surgical procedures for patients who undergo painful treatments and can be partially or fully sedated, remaining in an unconscious state during the operation. The specific molecular mechanism of anesthesia is still an open issue, but scientific evidence supports the hypothesis of the involvement of both putative hydrophobic cavities in membrane receptors as binding pockets and interactions between anesthetics and cytoplasmic proteins. Previous studies demonstrated the binding of VAs to tubulin. Since actin is the other major component of the cytoskeleton, this study involves an investigation of its interactions with four major anesthetics: halothane, isoflurane, sevoflurane, and desflurane. Molecular docking was implemented using the Molecular Operating Environment (MOE) software (version 2022.02) and applied to a G-actin monomer, extrapolating the relative binding affinities and root-mean-square deviation (RMSD) values. A comparison with the F-actin was also made to assess if the generally accepted idea about the enhanced F-to-G-actin transformation during anesthesia is warranted. Overall, our results confirm the solvent-like behavior of anesthetics, as evidenced by Van der Waals interactions as well as the relevant hydrogen bonds formed in the case of isoflurane and sevoflurane. Also, a comparison of the interactions of anesthetics with tubulin was made. Finally, the short- and long-term effects of anesthetics are discussed for their possible impact on the occurrence of mental disorders.

Regional and transmural dispersion of repolarisation in patients with Emery-Dreifuss muscular dystrophy

BACKGROUND

The development of malignant ventricular arrhythmias is a possible feature in Emery-Dreifuss muscular dystrophy (EDMD) patients with normal left ventricular systolic function. This event may be the cause of sudden cardiac death in EDMD patients. QTc dispersion (QTc-D), JTc dispersion (JTc-D) and Tpeak-end dispersion (TDR) could reflect the physiological variability of regional and transmural ventricular repolarisation and could provide a substrate for life-threatening ventricular arrhythmias.

AIM

The current study was designed to evaluate the heterogeneity of ventricular repolarisation in EDMD patients.

METHODS

Echocardiograms and electrocardiograms from 40 EDMD patients (age 20 ± 13) were evaluated and compared to those of 40 healthy age-matched controls.

RESULTS

The EDMD group, compared to the healthy control group, presented increased values of QTc-D (82.8 ± 44.1 vs. 53.3 ± 13.9, p = 0.003), JTc-D (73.6 ± 32.3 vs. 60.4 ± 11.1 ms, p = 0.001) and TDR (100.54 ± 19.06 vs. 92.15 ± 15.5 ms, p = 0.004). No correlation between QTc dispersion and ejection fraction (R = 0.2, p = 0.3) was found.

CONCLUSIONS

EDMD is associated with significantly increased regional and transmural heterogeneity of ventricular repolarisation, in the absence of impaired systolic and diastolic cardiac function.

Ocular pseudomyasthenia: report of a case with a pineal region tumor

A case presenting with clinical features of ocular myasthenia and a false-positive edrophonium test is reported. Brain CT and MRI scan revealed a pineal region tumor histologically verified as germinoma. We recommend evaluating patients with clinical features of myasthenia gravis (MG) confined to the ocular muscles for intracranial mass lesions.