RESUMO
Brugada electrocardiogram (ECG) pattern describes a characteristic right bundle branch block (RBBB) appearance with persistent ST-segment elevation in precordial leads V1 to V3, often associated with Brugada syndrome, a genetic sodium channelopathy, in the absence of ischemic or structural heart disease. Known triggers such as fever, electrolyte abnormalities, medications, or recreational drugs may elicit such an ECG pattern without a clear clinical significance yet creating a dilemma for clinicians providing care in the urgent setting. We present a case of reversible Brugada electrocardiogram pattern (BEP) after recreational use of delta-8-tetrahydrocannabinol (THC) and explore the need for further research on the safety of such an over-the-counter supplement.
RESUMO
We have reported that transcription of a hypothetical small open reading frame (orf60) in enteroaggregative E. coli (EAEC) strain 042 is impaired after mutation of aggR, which encodes a global virulence activator. We have also reported that the cryptic orf60 locus was linked to protection against EAEC diarrhea in two epidemiologic studies. Here, we report that the orf60 product acts as a negative regulator of aggR itself. The orf60 protein product lacks homology to known repressors, but displays 44-100% similarity to at least fifty previously undescribed small (<10 kDa) hypothetical proteins found in many gram negative pathogen genomes. Expression of orf60 homologs from enterotoxigenic E. coli (ETEC) repressed the expression of the AraC-transcriptional ETEC regulator CfaD/Rns and its regulon in ETEC strain H10407. Complementation in trans of EAEC 042orf60 by orf60 homologs from ETEC and the mouse pathogen Citrobacter rodentium resulted in dramatic suppression of aggR. A C. rodentium orf60 homolog mutant showed increased levels of activator RegA and increased colonization of the adult mouse. We propose the name Aar (AggR-activated regulator) for the clinically and epidemiologically important orf60 product in EAEC, and postulate the existence of a large family of homologs among pathogenic Enterobacteriaceae and Pasteurellaceae. We propose the name ANR (AraC Negative Regulators) for this family.
