Nicotine inhibits the production of proinflammatory mediators in human monocytes by suppression of I-kappaB phosphorylation and nuclear factor-kappaB transcriptional activity through nicotinic acetylcholine receptor alpha7.

Macrophages/monocytes and the proinflammatory mediators, such as tumour necrosis factor (TNF)-alpha, prostaglandin E(2) (PGE(2)), macrophage inflammatory protein (MIP)-1alpha and MIP-1alpha, play a critical role in the progression of immunological disorders including rheumatoid arthritis, Behçet's disease and Crohn's disease. In addition, the nicotinic acetylcholine receptor-alpha7 (alpha7nAChR) subunit is an essential regulator of inflammation. In this study, we evaluated the expression of the alpha7nAChR subunit on human peripheral monocytes and the effect of nicotine on the production of these proinflammatory mediators by activated monocytes. Fluorescein isothiocyanate (FITC)-labelled alpha-bungarotoxin demonstrated the cell surface expression of the alpha7nAchR subunit. Pretreatment with low-dose nicotine caused inhibition of TNF-alpha, PGE(2), MIP-1alpha and MIP-1alpha production, and mRNA expression of TNF-alpha, MIP-1alpha and MIP-1alpha and COX-2 in lipopolysaccharide (LPS)-activated monocytes. These suppressive effects of nicotine were caused at the transcriptional level and were mediated through alpha7nAChR. Nicotine suppressed the phosphorylation of I-kappaB, and then inhibited the transcriptional activity of nuclear factor-kappaB. These immunosuppressive effects of nicotine may contribute to the regulation of some immune diseases.

[A case of dumbbell neurogenic tumor in the posterior mediastinum].

We have recently experienced a dumbbell tumor that developed in the posterior mediastinum in a 64-year-old male. The patient suffered from dorsalgia one year and a half previously. Chest X-ray examinations revealed a well-defined boundary in the right posterior mediastinum. Myelography followed by computerized tomographic scanning (CT) revealed that the tumor developed in a paravertebral area linked with a vertebral canal through an intervertebral foramen and destructed a rib in growing in the paraspinal muscular layer. Longitudinal incision of about 10 cm was made downward from immediately above the first thoracic spinous process, and the chest was opened by posterolateral incision extending into the muscles of the back in an arc shape. The tumor was entirely excised by additional laminectomy. Since malignant schwannoma was diagnosed histologically, Linac X-ray of 50 Gray was given. The patient is now enjoying his healthy daily life with no postoperative complication 2 years after operation. Myelography followed by CT was proved to be quite useful in evaluating a relationship between the tumor and the spinal cord in the diagnosis of this disease.