A rare case of ulcerative colitis with diffuse parenchymal lung disease, spontaneous pneumomediastinum and subcutaneous emphysema.

A 50-year-old male, a tobacco smoker, who was known to have ulcerative colitis presented with dry cough, chest pain, dysponea and frequent passage of blood and mucous mixed stools. Physical examination revealed clubbing, subcutaneous emphysema of upper chest and auscultatory findings of crunching sound over pre-cordial area and basal crepitations. Spirometry was suggestive of restrictive pattern. High resolution computed tomography (HRCT) of thorax revealed pneumomediastinum, subcutaneous emphysema, bilateral diffuse centrilobular nodules and ground-glass haziness with mosaic pattern along with posterior basal fibrotic changes. The present case documents the uncommon pulmonary involvement of spontaneous pneumomediastinum and subcutaneous emphysema diffuse parenchymal lung disease, in a patient with ulcerative colitis.

Conformational transitions and specific heat anomaly in poly(dG-dC) and its methylated analogue.

The Zimm and Bragg theory of the helix<-->coil transition has been modified to explain order<-->order transitions in polynucleotides, in particular B<-->Z<-->psi(-)<-->coil transitions in poly(dG-dC) and poly(dG-me5dC). Lambda anomalies in specific heat measurements around the transition point have also been explained by a further modification of the same theory. Theoretical results are found to be in good agreement with the experimental data. The nucleation parameter is consistent with the stabilization/destabilization of the ordered states (Z helix) under various environmental conditions, e.g. methylation of cytosine residue at C5 position or change in the cationic concentration of the solvent.