No abstract

No abstract

Sidestream smoke from smoldering cigarette is the major source of environmental cigarette smoke. Cigarette smoke condensate (CSC) from sidestream smoke has been known to be mutagenic in Ames' Salmonella strains in the presence of an S9 metabolic activation system. We investigated a novel photomutagenic property of CSC with UVA-irradiation in the absence of metabolic activation. CSCs were collected from sidestream smoke of three Japanese brands of cigarettes using a smoking machine according to the ISO Standard. Bacterial cells with or without CSC were irradiated using a UVA light (320-400 nm) for 10-30 min. Photomutagenicity of CSC was more evident in E. coli WP2uvrA/pKM101 than in S. typhimurium TA100 and TA98. Photomutagenic potency (number of induced revertants/mg CSC) of sidestream CSC from Mild Seven One, an ultra-light tar cigarette, showed equal mutagenic potency to that from Seven Stars, a high tar cigarette. Photomutagenic potency of Pianissimo One, an ultra-light tar cigarette, was signiˆcantly higher than that of Seven Stars or Mild Seven One. We could not detect any increase of 8-OHdG formation in DNA isolated from cells irradiated with UVA in the presence of CSC. CSC with UVA irradiation caused A:T→T:A transversions most frequently, followed by A:T→G:C transitions. CSC was not photomutagenic in WP2/pKM101, indicating that the DNA damages generated by UVA-irradiated CSC were e‹ciently repaired by a nucleotide excision repair system. In addition, an error-prone translesion DNA synthesis by DNA polymerase RI encoded by mucAB genes on pKM101 is considered to be involved in photomutagenesis of CSC. We speculate a possible mechanism of production of radicals followed by DNA bulky adduct formation.

Background Coronary artery spasm has rarely been reported in pediatric patients. Previous studies have reported comorbidities and risk factors for coronary artery spasms. We present the case of a complete atrio-ventricular (AV) block that occurred in the absence of other risk factors immediately after direct laryngoscopy. Case presentation A 2-year-old girl developed severe coronary artery spasm after direct laryngoscopy for elective laryngeal papillomatosis resection. Immediately after the initiation of laryngoscopy, complete AV block and ST elevation on lead II of the electrocardiogram were observed. These findings indicated that the complete AV block was caused by a right coronary artery spasm. Conclusion Coronary artery spasm resulting in lethal arrhythmia rarely occurs in healthy pediatric patients. To the best of our knowledge, this is the first pediatric case of a severe coronary artery spasm resulting in a complete AV block due to direct laryngoscopy in a healthy patient.