Lessons of the month: Pyroglutamic acidosis: long-term paracetamol and a high anion gap.

An 84-year-old woman presented with confusion and Kussmaul respiration. She had a history of urosepsis, renal impairment and osteoarthrosis. The venous blood gas showed a marked metabolic acidosis with a high anion gap.

DNA double helices recognize mutual sequence homology in a protein free environment.

The structure and biological function of the DNA double helix are based on interactions recognizing sequence complementarity between two single strands of DNA. A single DNA strand can also recognize the double helix sequence by binding in its groove and forming a triplex. We now find that sequence recognition occurs between intact DNA duplexes without any single-stranded elements as well.