Varicella Pneumonia: Case Report and Review of a Potentially Lethal Complication of a Common Disease.

Varicella zoster virus causes varicella (chickenpox). It can be reactivated endogenously many years later to cause herpes zoster (shingles). Although varicella is usually a benign disease in healthy children, it resulted in over 11 000 hospitalizations and over 100 deaths every year, in all ages, in the United States. Morbidity was considerably worse in older teenagers and adults. Between 5% and 15% of cases of adult chickenpox will produce some form of pulmonary illness. Progression to pneumonia risk factors include pregnancy, age, smoking, chronic obstructive pulmonary disease, and immunosuppression. Typically, pulmonary symptoms occur 1 to 6 days after varicella zoster infection. They often include cough, fever, and dyspnea. Treatment is a 7-day course of intravenous acyclovir for varicella pneumonia. Early intervention may modify the course of this complication. This review illustrates practical features with a case of a 34-year-old female with severe varicella pneumonia. Despite the lack of significant past medical history and absence of immunosuppression, her pneumonia worsened and by using continuous positive airway pressure mask, intubation was avoided. More important, the radiographic progression of severe varicella pneumonia is shown. This highlights how a common disease of varicella can progress in an adult and manifest with significant organ malfunction.

Near-fatal kinking of mammary graft due to emphysematous lung disease.

Left internal mammary artery grafting is commonly used in elective coronary artery bypass graft surgery. We report a near-fatal case with graft kinking upon sternal closure due to distended, emphysematous lungs impinging on the mammary graft. After the sternum was closed, the patient suffered a severe hemodynamic deterioration. Surgical examination revealed kinking of his left internal mammary artery upon sternal closure due to distended, emphysematous lungs impinging on the mammary graft. Using an off-bypass technique, the kink in the mammary graft to the left anterior descending artery was removed by moving the origin of the left internal mammary artery to a hooded graft of a saphenous vein graft instead. In this position, the graft no longer was impinged upon by the distended emphysematous lungs. Subsequently, the patient's sternum was closed without hemodynamic impingement. Although chronic obstructive pulmonary disease is well described to increase complications in coronary artery bypass graft surgery, it has not been previously associated with the kinking of a left internal mammary artery. This report highlights another contribution that chronic obstructive pulmonary disease can make to increased morbidity following coronary artery bypass graft surgery and alerts readers to watch for this complication in susceptible patients.

Aromatic interactions promote self-association of collagen triple-helical peptides to higher-order structures.

Aromatic residues are relatively rare within the collagen triple helix, but they appear to play a specialized role in higher-order structure and function. The role of aromatic amino acids in the self-assembly of triple-helical peptides was investigated in terms of the kinetics of self-association, the nature of aggregated species formed, and the ability of these species to activate platelet aggregation. The presence of aromatic residues on both ends of a type IV collagen model peptide is observed to greatly accelerate the kinetics of self-association, decreasing the lag time and leading to insoluble, well-defined linear fibrils as well as small soluble aggregates. Both macroscopic visible aggregates and small multimolecular complexes in solution are capable of inducing platelet aggregation through the glycoprotein VI receptor on platelets. Proline-aromatic CH...pi interactions are often observed within globular proteins and in protein complexes, and examination of molecular packing in the crystal structure of the integrin binding collagen peptide shows Phe interacts with Pro/Hyp in a neighboring triple-helical molecule. An intermolecular interaction between aromatic amino acids and imino acids within the triple helix is also supported by the observed inhibitory effect of isolated Phe amino acids on the self-association of (Pro-Hyp-Gly)(10). Given the high fraction of Pro and Hyp residues on the surface of collagen molecules, it is likely that imino acid-aromatic CH...pi interactions are important in formation of higher-order structure. We suggest that the catalysis of type I collagen fibrillogenesis by nonhelical telopeptides is due to specific intermolecular CH...pi interactions between aromatic residues in the telopeptides and Pro/Hyp residues within the triple helix.