Tobacco smoke chemistry. 1. A chemical and mass spectrometric study of tobacco smoke alkyl 2-hydroxy-2-cyclopentenones

A series of alkyl 2-hydroxy-2-cyclopentenones, which comprise biologically and organoleptically active compounds, have been synthesized and subjected to high resolution mass spectrometric studies to clarify structurally significant fragmentation pathways. On the basis of these results, 26 alkyl 2-hydroxy-2-cyclopentenones were identified in the weakly acidic fraction of smoke condensate from American blend type cigarettes, eighteen of which had not been detected in tobacco smoke previously. The utility for identification purposes of the corresponding quinoxaline derivatives, obtained through condensation with o-phenylenediamine, is discussed.

Nocturnal hypoxaemia and cor pulmonale in severe chronic lung disease

The relation between daytime and nocturnal hypoxaemia on one hand and right ventricular failure (RVF) and hypertrophy (RVH) on the other was studied in 21 patients with severely reduced ventilatory capacity. RVH was assessed by myocardial scintigraphy, vector cardiography and echocardiography. Seven patients had suffered from acute RVF at least once. They had lower vital capacity and PaO2 and higher PaCO2 than patients without a history of RVF. They also had a more severe nocturnal hypoxaemia. They did not, however, have more severe RVH than patients without a history of RVF. Blood gases during daytime were not related to RVH. Oxygen saturation during sleep had a weak inverse relationship to RVH determined with scintigraphy, but not with the other methods. Nocturnal hypoxaemia was closely related to hypoxaemia and hypercapnia during daytime. A difference between daytime PaO2 and PaCO2 less than 2 kPa could with reasonable accuracy identify patients with nocturnal hypoxaemia.

Structural studies of the capsular polysaccharide elaborated by Haemophilus influenza type d

The structure of the capsular polysaccharide elaborated by Haemophilus influenzae type d has been investigated, methylation analysis and n.m.r. spectrometry being the principal methods used. It is concluded that the polysaccharide is composed of repeating units having the structure: leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-ManpNAcA-(1 leads to. In addition, single residues of L-alanine, L-serine, or L-threonine, in the proportions 2:2:1, are linked, through their amino groups, to C-6 of the 2-acetamido-2-deoxy-beta-D-mannopyranosyluronic acid residues. The degree of substitution (75-85%) varies for different preparations.

Structural studies of Shigella flexneri O-antigens

The structures of the O-antigens of all known serotypes and subserotypes of Shigella flexneri have been reinvestigated. The results support the assumption that these antigens are composed of a basic tetrasaccharide repeating unit (1), to which alpha-D-glucopyranosyl and/or O-acetyl groups are attached at different positions. Leads to 3)-beta-D-GlcNAcp-(1 leads to 2)-alpha-L-Rhap-(1 leads to 2)-alpha-L-Rhap-(1 leads to 3)-alpha-L-Rhap-(1 leads to The immunological determinants responsible for O-factors I, II, IV, V and 7, 8 contain alpha-D-gluco-pyranosyl groups, the locations of which have been determined. O-Factor 6 is due to O-acetyl groups, linked to O-2 of the 3-substituted alpha-L-rhamnopyranosyl residue in unit 1 and O-factor III seems to be due to the same groups. The chemical natures of the determinants responsible for O-factors 4 and 3, 4 are still obscure. The structural studies indicate that the immunological classification of Sh. flexneri serotypes and subserotypes, as regards these O-factors, may need revision.

Structural studies of the Shigella flexneri variant X, type 5 a and type 5 b O-antigens

Previous studies of different Shigella flexneri O-antigens indicate that their O-specific region is composed of oligosaccharide repeating units containing a basic tetrasaccharide structure, to which alpha-D-glucopyranosyl groups and O-acetyl groups may be attached to different positions. Structural studies of O-antigens from variant X, type 5a and type 5b lend further support to this assumption. These antigens contain terminal alpha-D-glucopyranosyl groups, one each per repeating unit in X and 5a, two in 5b. The location of these groups in the repeating unit has been determined.