Nonobstructing Colonic Dilatation and Colon Perforations Following Renal Transplantation

Nonobstructing colonic dilatation has not been commonly reported following renal transplantation, and colon perforations carry a high morbidity and mortality in this population. During a 7-year period, nonobstructing colonic dilatation developed in 13 adults 1 to 13 days after renal transplantation. Twelve (92%) of the 13 had poorly functioning allografts. Five (83%) of the 6 with and 2 (29%) of the 7 without colonoscopy had resolution of nonobstructing colonic dilatation. Of the seven right-sided colon perforations during this period, six were associated with nonobstructing colonic dilatation. An additional 4 patients had diverticular perforations in the left colon. Of a total of 11 patients with colon perforation, 7 had surgery within 24 hours of the perforation and 6 (86%) of these survived. Only 1 (25%) of the 4 having surgery more than 24 hours later survived. Six of the survivors retained functioning allografts. Nonobstructing colonic dilatation seems to be a potential complication of poor graft function after renal transplantation, and colonoscopy is effective in its treatment. In patients with colon perforations, early surgery and reduced immunosuppression are essential in decreasing mortality. © 1990, American Medical Association. All rights reserved

Dilatation symmetry in higher dimensions and the vanishing of the cosmological constant

A wide class of dilatation symmetric effective actions in higher dimensions leads to a vanishing four-dimensional cosmological constant. This requires no tuning of parameters and results from the absence of an allowed potential for the scalar dilaton field. The field equations admit many solutions with flat four-dimensional space and non-vanishing gauge couplings. In a more general setting, these are candidates for asymptotic states of cosmological runaway solutions, where dilatation symmetry is realized dynamically if a fixed point is approached as time goes to infinity. Dilatation anomalies during the runaway can lift the degeneracy of solutions and lead to an observable dynamical dark energy.Comment: 4 page