Hiroki Numanami

Doxycycline Modulates Nitric Oxide Production in Murine Lung Epithelial Cells

Many effective therapeutic agents exhibit effects that are different from their intended primary mode of action. Antibiotics such as doxycycline and erythromycin A are no exception. They also display anti-inflammatory activity. Using LA4 murine lung alveolar epithelial cells, effects of doxycycline and erythromycin A on inducible NO synthase (iNOS) NO production as well as iNOS protein and mRNA production were investigated. Induction of iNOS was accomplished by treatment with cytomix (TNF-α, IL-1β, and IFN-γ each at 5 ng/ml). Production of NO or iNOS was not detected in controls with or without erythromycin A. In the presence of cytomix, erythromycin A did not decrease NO, nitrite, iNOS protein, or mRNA production. In contrast, doxycycline caused a dose-dependent decrease in NO, nitrite, iNOS protein, and mRNA production in cytomix-treated cells. Doxycycline at 30 μg/ml produced a 90% decrease in nitrite and NO production and a 52% decrease in iNOS mRNA transcription compared with cytomix treatment alone. Actinomycin D treatment suggests that doxycycline decreases stability of iNOS mRNA in cytomix-treated cells. To determine a mechanism for the decrease in iNOS expression, NF-κB and AP-1 transcription regulatory systems and p38 MAPK were examined. Doxycycline treatment gave no statistically significant change in NF-κB activation but did decrease p38 MAPK protein in cytomix-treated cells by 50%, suggesting that p38 MAPK may be responsible for stabilization of iNOS mRNA. These results demonstrate that doxycycline decreases NO production from iNOS by destabilization of iNOS mRNA via decreased expression of p38 MAPK.

Methotrexate stimulates lung epithelial cells to release inflammatory cell chemotactic activities.

Methotrexate-induced pneumonitis has been reported as an infrequent but potentially serious complication of therapy in a variety of malignant and benignconditions. Because inflammatorycell infiltration is concerned with the development of methotrexate-induced pneumoinitis, and because airway epithelial cells participate in the orchestration of lung inflammation, the authors determined whether methotrexate might stimulate airway epithelial cells (A549 cells) to release neutrophil, monocyte, and eosinophil chemotactic activities (NCA, MCA, and ECA). A549 cells released NCA, MCA, and ECA in a dose- and time-dependent manner in response to methotrexate. Partial characterization revealed the heterogeneity of NCA, MCA, and ECA. The release of chemotactic activity was blocked by lipoxygenase inhibitors and cycloheximide. NCA was inhibited by leukotriene (LT) B 4 receptor antagonist, and anti-interleukin (IL)-8 and granulocyte colony-stimulatingfactor (G-CSF) antibodies. MCA was attenuated by LTB 4 receptor antagonist, and anti-monocyte chemoattractant protein (MCP)-1 and granulocyte-macrophage CSF (GM-CSF) antibodies. ECA was attenuated by LTB 4 receptor antagonist, and anti-IL-8 and GM-CSF antibodies. The release of IL-8, G-CSF, MCP-1, GM-CSF, and LTB 4 from A549 cells significantly increased in response to methotrexate. The mRNA expression of IL-8 and MCP-1 was augmented by methotrexate stimulation. These data suggest that type II epithelial cells may modulate inflammatory cell recruitment into the lung by releasing NCA, MCA, and ECA in response to methotrexate.

Enhanced Activity of Human IL-10 After Nitration in Reducing Human IL-1 Production by Stimulated Peripheral Blood Mononuclear Cells

Nitric oxide and superoxide form the unstable compound, peroxynitrite, which can nitrate proteins and compromise function of proinflammatory cytokines at sites of inflammation. Reduced function of proinflammatory proteins such as IL-8, macrophage inflammatory protein-1α, and eotaxin suggest an anti-inflammatory effect of nitration. The effects of nitration on anti-inflammatory cytokines such as IL-10 are unknown. We hypothesized that peroxynitrite would modify the function of anti-inflammatory cytokines like IL-10. To test this hypothesis, the capacity of recombinant human IL-10 to inhibit production of human IL-1β (IL-1) from LPS-stimulated human PBMC was evaluated. Human IL-10 was nitrated by incubation with peroxynitrite or by incubation with 3-morpholinosydnonimine, a peroxynitrite generator, for 2 h and then incubated with LPS-stimulated PBMC for 6 h, and IL-1 was measured in the culture supernatant fluids. Human IL-1 production was significantly lower in the peroxynitrite- or 3-morpholinosydnonimine-nitrated IL-10 group than in the IL-10 controls (p < 0.05, all comparisons). This finding demonstrates that although peroxynitrite inhibits proinflammatory cytokines, it may augment anti-inflammatory cytokines and further point to an important role for peroxynitrite in the regulation of inflammation.

Solitary aneurysm of the innominate vein.

Two cases of isolated saccular aneurysms of the innominate vein are presented that appeared as mediastinal masses. Contrast-enhanced computed tomography (CT) allowed for accurate diagnosis in one patient, while the second patient had atypical CT findings that led to thoracotomy for proper diagnosis. A diagnosis of innominate vein aneurysm should be considered when a uniform attenuation mediastinal mass is seen on CT so that unnecessary biopsy and surgery can be avoided.

Intrapleural rupture of a cystic thymoma.

Although cystic degeneration of a thymoma is not uncommon, rupture of a cystic thymoma is rare. The authors report a patient with sudden chest pain and dyspnea due to rupture of a cystic thymoma into the right pleural space.

Nine cases of catamenial pneumothorax: a report of a singlecenter experience

Background Catamenial pneumothorax (CP) is defined as repeated pneumothorax related to menses and thoracic endometriosis. We performed a retrospective analysis of nine patients with CP to determine the clinical features as well as the effects of treatment and recurrence rates. Methods A retrospective review was conducted of the clinical and pathologic data in all CP patients undergoing treatment at our institution. Nine patients underwent treatment for CP. Of these, six underwent surgical treatment 8 times. Results The median age was 36 years. Six patients had experienced delivery. The laterality of the pneumothorax was right in all patients. Pelvic endometriosis was diagnosed in five patients. Six patients underwent surgical treatment. Partial resection of the lung was performed in four patients and partial resection of the diaphragm in five. Of these, both resections were performed in four patients. A pathological diagnosis of endometriosis was achieved in only three patients. The observation period was 16.7 months. In the six patients with surgical resection, five experienced recurrence at various intervals. Onset of pneumothorax occurred pre- or menstrual period in most cases. Conclusions The diagnosis and treatment of CP is not easy. A multidisciplinary approach and skillful management are required. Recurrence of CP is common following a temporary cure of pneumothorax by surgical treatment.

Thoracoscopic Thymectomy Using a Subxiphoid Approach for Anterior Mediastinal Tumors

PURPOSE Video-assisted thoracic surgery (VATS) techniques have been widely used for resection of mediastinal tumors. This study investigated the usefulness of the subxiphoid approach in thoracoscopic thymectomy. METHODS In all, 36 patients with anterior mediastinal tumor underwent thymectomy using the subxiphoid approach in two Japanese institutions. These patients were retrospectively reviewed and analyzed. RESULTS There were 16 females and 20 males with a mean age of 57 years. Five patients underwent partial thymectomy (PT), 27 underwent total or subtotal thymectomy, and 4 underwent thymectomy with combined resection (CR) of the surrounding organs or tissues. The mean maximum tumor diameter, amount of resected tissue, and blood loss were 4.1 cm, 72.5 g, and 20.6 g, respectively. More than half of tumors were diagnosed as thymoma (n = 19). The operation time was prolonged with a greater volume of thymectomy. The duration of chest tube drainage and postoperative stay were 1.7 ± 1.0 days and 5.9 ± 7.6 days, respectively. Four patients suffered intraoperative and postoperative complications, as follows: bleeding of the innominate vein, bleeding of the internal thoracic vein, crisis of myasthenia gravis (MG), pericarditis, and phrenic nerve paralysis. There were no mortalities after surgery. CONCLUSION Subxiphoid thoracoscopic thymectomy might be a safe and useful approach for mediastinal tumors.