Fragmentations of dipeptides in plasma desorption mass spectrometry: new rules for the sequence elucidation of oligopeptides.

252Cf plasma desorption mass spectrometry is well suited for determining both composition and sequence of unknown small oligopeptides. A systematic study of a large number of dipeptides first leads to establishing common rules of fragmentation from positive ion mass spectra. These rules are then applied to the sequence elucidation of larger peptides.

[Chronic renal failure and lithiasis]. / Insuffisance rénale chronique et lithiase.

After analyzing 39 cases, the authors go on to describe the virtues of surgical treatment of non-uric lithiasis after correct evaluation (lateral urography, CT scanning, retrograde ureteropyelography). The operative techniques draw considerable benefits from intraoperative radiography and, when necessary, the clamping of the renal pedicle under pharmacological protection. Surgical management offers the only possible means of preventing aggravation of the renal failure.