The large window ductus: a surgical trap

A rare window type of patent ductus arteriosus is reported that was large (15 mm in maximal transverse dimension) but had virtually no length and hence was externally invisible. The smaller aortic isthmus (4 mm in diameter), which was intrapericardial, was mistaken for the ductus and was inadvertently clip-occluded, leading to death. After a specific diagnosis is made, the large window ductus should be patched on cardiopulmonary bypass with a transpulmonary approach.     

Differentiation of lysine/glutamine in peptide sequence analysis by electrospray ionization sequential mass spectrometry coupled with a quadrupole ion trap

Electrospray ionization coupled to a quadrupole ion trap mass spectrometer is used to differentiate between the isobaric amino acids lysine and glutamine in sequence analysis of peptides. Collision-induced dissociation is used for fragmentation. Several isobaric peptides with one or more lysines or glutamines at different positions were investigated. The ambiguous amino acid either in the peptide chain or at the C- or N-terminus can be clearly identified based on specific side chain fragment ions resulting from MS3 or MS4 of B- and Y"-fragment ions.