[Mass spectrum and uniformity of decomposition of certain 2-substituted 9-(o-chlorbenzyl)-8-azahypoxanthines].

The regularities of mass spectrometric fragmentation under electron impact of new 9-(o-chlorobenzyl)-8-azahypoxantines with (N-aryl)amidocarbonylmethylthiomethyl substituents in position 2 were studied. The main fragmentation pathways are the elimination of Ar-NH+ and o-chlorobenzyl ions and cleavage of C-S bonds, characteristic of organic sulfides. During the fragmentations, some rearrangements occur, consisting in the transfer of labile hydrogen atoms from the alpha-positions to ions being eliminated.

[Preoperative instrumental diagnosis of postoperative choledocholithiasis].

Experience in examination of 221 patients with postoperative cholangiolithiasis is discussed. Analysis of the results of instrumental examination ERPCG to surpass all the existing methods of diagnosis of stones in the bile ducts in informativeness and safety. A diagnostic algorithm of examination is suggested by means of which the necessary tactical problems connected with the forthcoming operation were solved in 98.

[Recurrent and residual stones in the bile ducts].

Data of 205 patients with recurrent (48) and residual (157) choledocholithiases are presented. In most observations postoperative cholelithiasis proceeded by the type of chronic intermittent obturation of bile ducts. Highly effective method of diagnosing recurrent and residual calculi is thought to be the endoscopic retrograde pancreatocholangiography, best results of the treatment being obtained after the endoscopic papillosphincterotomy which should be used as the operation of choice.