Hiroto Niizeki

Hypoxia enhances the expression of autocrine motility factor and the motility of human pancreatic cancer cells.

The incidence of distant metastases is higher in the tumours with low oxygen pressure than in those with high oxygen pressure. It is well known that hypoxia induces the transcription of various genes involved in angiogenesis and anaerobic metabolism necessary for the growth of tumour cells in vivo, suggesting that hypoxia may also induce the transcription of metastasis-associated genes. We sought to identify the metastasis-associated genes differentially expressed in tumour cells under hypoxic conditions with the use of a DNA microarray system. We found that hypoxia enhanced the expression of autocrine motility factor mRNA in various cancer cells and also enhanced the random motility of pancreatic cancer cells. Autocrine motility factor inhibitors abrogated the increase of motility under hypoxic conditions. In order to explore the roles of hypoxia-inducible factor-1α, we established hypoxia-inducible factor-1α-transfectants and dominant negative hypoxia-inducible factor-1α-transfectants. Transfection with hypoxia-inducible factor-1α and dominant-negative hypoxia-inducible factor-1α enhanced and suppressed the expression of autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA and the random motility, respectively. These results suggest that hypoxia may promote the metastatic potential of cancer cells through the enhanced autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA expression and that the disruption of the hypoxia-inducible factor-1 pathway may be an effective treatment for metastasis.

Simultaneous Resection of Bilateral Intralobar and Extralobar Pulmonary Sequestrations With Video-Assisted Thoracoscopic Surgery

The term pulmonary sequestration is applied to a pulmonary lobe or portion of a lobe that is supplied by an anomalous systemic artery and drain either into the systemic or pulmonary veins. The conditions are divided into intralobar pulmonary sequestration, in which the sequestration is situated inside the visceral pleura of a normal lobe, and extralobar sequestration, in which the sequestration is surrounded by its own pleura. Most sequestrations are unilateral; bilateral sequestrations are rare. We report the case of a synchronous bilateral intralobar and extralobar pulmonary sequestrations resected simultaneously with video-assisted thoracoscopic surgery.

Extrapleural hematoma as a complication following thoracotomy for pulmonary lobectomy

Extrapleural hematoma as a complication following thoracic surgery is rare. We report a case of an extrapleural hematoma following pleural lobectomy that resolved completely with nonsurgical treatment. A 63-year-old woman underwent left lower lobectomy for lung cancer through a left posterolateral thoracotomy. She had been prescribed the anticoagulant cilostazol to increase her heart rate for atrioventricular dissociation. Preoperatively, it was stopped, and a temporary pacemaker was placed to counteract bradycardia via the right jugular vein without complication. The chest tube was removed, and cilostazol was resumed on the third postoperative day. On day 7, she suddenly experienced left shoulder pain followed by hypotension, tachycardia, and anemia. Enhanced computed tomography (CT) revealed an extrapleural hematoma rather than a hemothorax. She became symptomatic after rapid infusion. The hematoma resolved without an invasive intervention. The CT results 189 days after the onset showed almost complete regression of the hematoma.