Short QT Syndrome: A Comprehensive Genetic Interpretation and Clinical Translation of Rare Variants

Short QT syndrome, one of the most lethal entities associated with sudden cardiac death, is a rare genetic disease characterized by short QT intervals detected by electrocardiogram. Several genetic variants are causally linked to the disease, but there has yet to be a comprehensive analysis of variants among patients with short QT syndrome. To fill this gap, we performed an exhaustive study of variants currently catalogued as deleterious in short QT syndrome according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Analysis of the 32 variants described in the literature determined that only nine (28.12%) have a conclusive pathogenic role. All definitively pathogenic variants are located in KCNQ1, KCNH2, or KCNJ2; three genes encoding potassium channels. Other variants located in genes encoding calcium or sodium channels are associated with electrical alterations concomitant with shortened QT intervals but do not guarantee a diagnosis of short QT syndrome. We recommend caution regarding previously reported variants classified as pathogenic. An exhaustive re-analysis is necessary to clarify the role of each variant before routinely translating genetic findings to the clinical setting.

Surfactant Enhanced Washing of Drilling Fluids, a Promising Remediation Technique

In this work, drilling fluids with 135 400 mg kg−1 of total petroleum hydrocarbons (TPH) were washed with six different surfactants (the non-ionic Emulgin 600, Emulgin 1000, Brij 35 and Tween 80, ionic SDS, and zwitterionic Polafix CAPB) and their mixtures. Due to the high Ca content in the samples, three different approaches were employed when washing with SDS, because of its ionic character: a) using mixtures of surfactants, b) addition of NaCl, and c) addition of a Ca sequestrant, i. e., sodium metasilicate. Drilling fluids were washed; TPH, electric conductivity (EC, as an indirect measurement of salinity), and pH values were measured before and after the washing process. Surface tension of the clean and spent washing solutions (surfactant or surfactants mixture, with or without salts) was measured.

TPH removals as high as 75% were achieved using SDS + sodium metasilicate. EC values diminished 75% with the washing process, but for the experiments in which salts were added, increments in electric conductivity of up to 367% were observed. Regarding the pH changes, initial sample pH value was 7.77, and in most cases this value was reduced, except for some of the cases where salt was added. Surfactant solution's surface tension changes (before and after the washing process) correlated fairly with TPH removals.