Transgenic mouse models to determine the role of epidermal growth factor receptor in epithelial cell proliferation, apoptosis, and asbestosis

Treatment of severe sepsis: where next? Current and future treatment approaches after the introduction of drotrecogin alfa

Severely septic patients continue to experience excessive morbidity and mortality despite recent advances in critical care. Although significant resources have been invested in new treatments, almost all have failed to improve outcomes. An improved understanding of sepsis pathophysiology, including the complex interactions between inflammatory, coagulation, and fibrinolytic systems, has accelerated the development of novel treatments. Recombinant human activated protein C (rhAPC), or drotrecogin alfa (activated) (DAA), is currently the only US Food and Drug Administration (FDA)-approved medicine for the treatment of severe sepsis, and only in patients with a high risk of death. This review will discuss the treatment of severe sepsis, focusing on recent discoveries and unresolved questions about DAA's optimal use. Increasing pharmacological experience has generated enthusiasm for investigating medicines already approved for other indications as treatments for severe sepsis. Replacement doses of hydrocortisone and vasopressin may reduce mortality and improve hypotension, respectively, in a subgroup of patients with catecholamine-refractory septic shock. In addition to discussing these new indications, this review will detail the provocative preliminary data from four promising treatments, including two novel modalities: antagonizing high mobility group box protein and inhibiting tissue factor (TF). Observational data from the uncontrolled administration of heparin or statins in septic patients will also be reviewed.

Role of Iron in Inactivation of Epidermal Growth Factor Receptor after Asbestos Treatment of Human Lung and Pleural Target Cells

Although the mechanism by which asbestos causes cancer remains unknown, iron associated with asbestos is thought to play a role in the pathogenic effects of fibers. Here, we examined the effects of asbestos on the epidermal growth factor receptor (EGFR) in human lung epithelial (A549) cells, human pleural mesothelial (MET5A) cells, and normal human small airway epithelial (SAEC) cells. Treatment of A549, MET5A, and SAEC cells with asbestos caused a significant reduction of EGFR tyrosine phosphorylation. This was both time- (15 min to 24 h) and concentration-dependent (1.5, 3, and 6 mug/cm(2)) in A549 cells. Also, treatment with 6 mug/cm(2) crocidolite for 24 h diminished the phosphorylation levels of human EGFR 2 (HER2). Exposure of A549 cells to 6 mug/cm(2) crocidolite for 3-24 h resulted in no detectable Y1045 phosphorylation and no apparent degradation of the EGFR. Inhibition of fiber endocytosis resulted in a considerable inhibition of EGFR dephosphorylation. Removal of iron from asbestos by desferrioxamine B or phytic acid inhibited asbestos-induced decreases in EGFR phosphorylation. The effects of crocidolite, amosite, and chrysotile on the EGFR phosphorylation state appeared to be directly related to the amount of iron mobilized from these fibers. These results strongly suggest that iron plays an important role in asbestos-induced inactivation of EGFR.