Anaesthesia in first degree atrioventricular block.

A patient with an intracardiac conduction defect characterised by first degree atrioventricular block due to slowed transmission through the atrioventricular node with increased refractoriness of the node, is described. Asymptomatic first degree block, rarely progressing to transient Wenckebach (type 1 second degree) block had been present for a period of 32 years until general anaesthesia was required, when profound bradycardia attributable to complete atrioventricular block developed abruptly. Subsequent investigations located delayed intracardiac conduction through the atrioventricular node, and indicated excess vagal activity rather than structural disease as the cause.

Glutathione adducts of N-methyl-4-aminoazobenzene formed in vivo and by reaction of N-benzoyloxy-N-methyl-4-aminoazobenzene with glutathione.

N-Benzoyloxy-N-methyl-4-aminoazobenzene (N-BzO-MAB) is believed to be an analogue of the ultimate carcinogenic form of N,N-dimethyl-4-aminoazobenzene (DAB). The reaction of N-BzO-MAB with glutathione in vitro yielded one major and two minor aminoazo dye-glutathione adducts. After purification by ion exchange chromatography and high pressure liquid chromatography, analysis of chemical properties, and the measurement of ultraviolet, visible, proton magnetic resonance, and mass spectra, the major and one minor adduct were identified as 3-(glutathion-S-yl)-N-methyl-4-aminoazobenzene (3-GS-MAB) and 2'-(glutathion-S-yl)-N-methyl-4-aminoazobenzene (2'-GS-MAB) respectively.