ABSTRACT
Delivery of IgA to the mucosal surface occurs via transcytosis of polymeric IgA (pIgA) across the epithelium, a process mediated by the pIgR. Several factors increase pIgR expression in human epithelial cells, including IL-4 and IFN-gamma. Using an RNase protection assay, we found that IL-4 and IFN-gamma increase steady state levels of pIgR mRNA in both human intestinal (HT29) and airway (Calu-3) epithelial cells. Time course studies in HT29 clone 19A cells showed that with each cytokine alone and with both together: 1) there was a significant lag before mRNA levels increased; 2) maximal levels were not reached until 48-72 h after the addition of cytokines; 3) mRNA levels remained elevated in the continued presence of cytokines; and 4) addition of actinomycin D or removal of cytokines led to decreases in mRNA levels with a half-life of approximately 20-28 h. Cytokine-dependent increases in steady state levels of pIgR mRNA were inhibited by cycloheximide and by protein tyrosine kinase inhibitors but not by inhibitors of protein kinase C or cAMP-dependent protein kinase A. Both IFN-gamma and IL-4 increased expression of the inducible transcription factor IFN regulatory factor-1 (IRF-1), but levels of IRF-1 only weakly correlated with levels of pIgR mRNA, suggesting that additional transcription factors are required. These studies provide additional insights into the mechanisms by which cytokines regulate expression of the pIgR, a central player in mucosal immunity.
Subject(s)
Interferon-gamma/physiology , Interleukin-4/physiology , Intestinal Mucosa/metabolism , Lung/metabolism , RNA, Messenger/metabolism , Receptors, Polymeric Immunoglobulin/genetics , Receptors, Polymeric Immunoglobulin/metabolism , Cycloheximide/pharmacology , Cytokines/physiology , DNA-Binding Proteins/biosynthesis , Drug Synergism , Enzyme Inhibitors/pharmacology , Epithelial Cells/immunology , Epithelial Cells/metabolism , HT29 Cells/metabolism , Humans , Interferon Regulatory Factor-1 , Intestinal Mucosa/drug effects , Intestinal Mucosa/immunology , Lung/cytology , Lung/drug effects , Phosphoproteins/biosynthesis , Protein-Tyrosine Kinases/antagonists & inhibitors , Proto-Oncogene Proteins c-jun/biosynthesis , RNA, Messenger/drug effects , Time Factors , Transcription Factors/biosynthesis , Tumor Cells, CulturedABSTRACT
PURPOSE: To assess the technical success rate, complications, and effect on intraoperative blood loss of preoperative transarterial embolization of cervical spine tumors. METHODS: A retrospective analysis was performed on 38 patients with tumors of the cervical spine; 69 vertebrae were affected. Polyvinyl alcohol particles, coils, gelfoam particles, either alone or in combination, were used for preoperative tumor embolization. After embolization a total of 57 corporectomies with titanium basket implantation were performed. RESULTS: In 36 of 38 patients, complete (n = 27) or partial (n = 9) embolization was achieved. In 23 patients one vertebral artery was completely occluded by coil placement, and in one patient the ipsilateral internal and external carotid arteries were occluded in addition. No neurological complications could be directly related to the embolization, but two postoperative brain stem infarctions occurred. The mean intraoperative blood loss was 2.4 L. CONCLUSION: Transarterial embolization of cervical spine tumors is a safe and effective procedure to facilitate extensive surgery.
