Tetsuo Kido

New prognostic indicator for non‐small‐cell lung cancer, quantitation of thymidylate synthase by real‐time reverse transcription polymerase chain reaction

Thymidylate synthase (TS) is an enzyme that catalyzes an important DNA biosynthesis process. The gene expression of TS has not been reported in non‐small‐cell lung cancer (NSCLC) patients. To clarify the correlation between TS mRNA levels and clinicopathological features of NSCLC, we examined 70 Stage I and II NSCLC patients for intra‐tumoral expression of TS using TaqMan reverse transcription polymerase chain reaction (RT‐PCR) assay and immunohistochemistry methods. We also investigated the TS promoter 28 bp polymorphism in 48 cancer tissues using PCR amplification of genomic DNA. Lung cancer tissue showed higher TS mRNA levels than normal lung tissue (Mann‐Whitney U‐tests; p = 0.0020). Further, TS mRNA expression was correlated with immunohistochemical TS expression (p = 0.029). We obtained 2 different DNA fragments, which indicated triple‐repeat (3R) and double‐repeat (2R) type alleles. Cancer tissues with the 3R/3R genotype showed significantly higher TS mRNA levels as compared to those with other genotypes (p = 0.0019). The TS genotype was also correlated with immunohistochemical TS expression (χ2 test; p = 0.0079). The disease‐free survival of the low TS mRNA level group was significantly better than those with high TS mRNA levels (log‐rank test; p = 0.010), however, there were no significant differences found by immunohistochemical evaluation (p = 0.34) or TS genotype analysis (p = 0.11). A multivariate analysis revealed that high TS mRNA levels independently contributed to disease‐free survival. The quantitation of TS mRNA levels is clinically more sensitive and useful for determining the prognosis of Stage I and II NSCLC patients than an immunohistochemical evaluation.

Resection of anterior mediastinal masses through an infrasternal approach

A video-assisted surgical technique for benign anterior mediastinal lesions is described. In 3 patients, the Laparolift system was used to lift the lower sternum before resection. This operation is less invasive and cosmetically more pleasing than median sternotomy. Unlike thoracoscopy, this procedure avoids opening the chest and can be performed in patients with pleural adhesions or pulmonary insufficiency in whom differential lung ventilation is impossible. At present, this technique is considered suitable only for benign lesions.

Alternative choices of total and partial thymectomy in video-assisted resection of noninvasive thymomas

BackgroundThe purpose of this report is to discuss the appropriate choice of procedures for video-assisted resection of thymoma according to factors such as the presence of myasthenia gravis or location of the tumor.MethodsWe evaluated the short-term results of thoracoscopic surgery for 30 consecutive cases of noninvasive thymoma. Unilateral thoracoscopic partial (or subtotal) thymectomy (UTPT) was employed in patients with nonmyasthenic thymoma localized to the unilateral mediastinum, and extended (or total) thymectomy by an infrasternal mediastinal approach (ETIS) in myasthenic cases or those in which total thymectomy was considered inevitable.ResultsUTPT was performed on 11 nonmyasthenic patients, and ETIS on 19 (13 myasthenics and six nonmyasthenics). Three patients in the ETIS group underwent conversion to sternotomy because of pericardial dissemination, pleural adhesion, and vascular injury, respectively. The mean surgical duration was 163 min and 224 min and mean blood loss was 123 g versus 149 g for UTPT and ETIS, respectively. Post-thymomectomy myasthenia occurred in a patient after UTPT who made an excellent recovery to remission after the re-UTPT. There has not been any recurrence detected for 48 months of mean postoperative follow-up.ConclusionsOur trial regarding the choice of total or partial thymectomy in thoracoscopic surgery for thymomas yielded acceptable results that warrant further investigations into long-term survival and recurrence after longer-term observation of patients undergoing these procedures.

Resection and reconstruction of the airway in patients with advanced thyroid cancer

The prognosis of patients with differentiated thyroid cancer is relatively fair, with a 10-year survival rate above 80%. One of the important prognostic factors is cancer invasion to the airway. For the last 25 years we have been performing combined resection of the trachea and larynx and have reported a relatively good 10-year survival (67.7%) and improved quality of life (QOL). However, operative complications associated with the procedure, especially insufficiency of the anastomosis and bleeding from large vessels, are life-threatening. Of 40 patients who underwent resection of the trachea, insufficiency of the anastomosis occurred in 4 and subsequent massive bleeding from carotid artery due to neck infection in 2. Tracheal resection should be carried out carefully by avoiding insufficiency. We have concluded that combined resection is a good treatment choice for survival and good QOL when performed for local control in patients with differentiated thyroid cancer.

Intermediate-term oncologic outcomes after video-assisted thoracoscopic thymectomy for early-stage thymoma.

OBJECTIVE To evaluate the impact on patient survival of video-assisted thoracoscopic surgery (VATS) thymectomy for the treatment of early-stage thymoma, by comparing the intermediate-term oncologic outcomes with outcomes after open thymectomy. METHODS Eighty-two patients who underwent complete resection of a Masaoka stage I or II thymoma between November 1998 and December 2011 were reviewed. RESULTS The patients included 32 men and 50 women (median age, 57 years; range, 20-90 years), of whom 44 had stage I thymoma and 38 had stage II thymoma. Seventy-one patients underwent VATS, of whom 4 (5.6%) underwent conversion to open thymectomy; the remaining 11 patients underwent planned open thymectomy. Thirty-six patients underwent total thymectomy and 46 underwent partial thymectomy. Operative mortality was nil. The tumor stage, tumor size, and proportion of patients who underwent total thymectomy were not significantly different between the open and VATS thymectomy groups. The median follow-up period was 49 months (VATS, 48 months; open, 52 months). There was a significant difference between the 2 groups for the estimated 5-year overall survival (VATS, 97.0%; open, 79.5%; P=.041) but not in the estimated 5-year recurrence-free survival. CONCLUSIONS Our findings indicate that the intermediate-term oncologic outcomes after VATS thymectomy for early-stage thymoma are as favorable as outcomes after open thymectomy. Further follow-up is still required to evaluate the long-term outcomes after VATS thymectomy.

Swan-Ganz catheter-induced pseudoaneurysm of the pulmonary artery.

Pseudoaneurysm of the pulmonary artery (PA) induced by Swan-Ganz catheter injury is an important complication with high mortality. We report a case of PA pseudoaneurysm treated by PA repair. A 52-year-old woman developing infiltrate in the right lung field in chest radiography after a second mitral valve replacement was diagnosed with PA pseudoaneurysm confirmed by contrast-enhanced computed tomography and pulmonary angiography. The cause was considered Swan-Ganz catheter injury. The patient was carefully observed because there was no evidence of bronchial hemorrhage. The perforation was closed and the cavity plicated under extracorporeal circulation to avoid delayed rupture of the pseudoaneurysm when she underwent a third mitral valve replacement.

Pheochromocytoma of the posterior mediastinum undiagnosed until the onset of intraoperative hypertension

An asymptomatic 42-year-old man was diagnosed with a posterior mediastinal mass, most likely a nonfunctioning, benign, neurogenic tumor for which thoracoscopic surgery was initially indicated. However, the systemic blood pressure rapidly increased to a critical level immediately after starting the surgical manipulation of the tumor, which was suggestive of a hyperfunctioning pheochromocytoma. The tumor was removed after controlling the blood pressure and was histologically diagnosed as a pheochromocytoma. The patient had an uneventful course, and the tumor was proven to be sporadic through further postoperative investigations. The possibility of extraadrenal pheochromocytoma should be considered in the preoperative diagnosis of an intrathoracic paraaortic tumor, even in an asymptomatic patient.

Abnormal persistence of the right vitelline vein

The authors describe a case of intestinal obstruction due to a mesodiverticular band, in which both vitelline artery and vein remnants were affirmed to be present histologically. Reviewing case reports in literature, it was revealed that the vein found in the band was the right vitelline vein remnant and that this was an important fact which proved the hypothesis that the superior mesenteric vein derives from the right vitelline vein.

Advantage of earlier thoracoscopic clipping of thoracic duct for post-operation chylothorax following thoracic aneurysm surgery

We report that an earlier thoracoscopic clipping of the thoracic duct was advantageous in a case of post-operation chylothorax that occurred following thoracic aneurysm surgery. A 61-year-old man developed chylothorax on postoperative day 2 following graft replacement of the descending thoracic aorta using a left-sided thoracotomy. Since a replaced graft infection is lethal, earlier thoracoscopic clipping of the thoracic duct through the right side chest wall was indicated. The patient underwent thoracoscopic clipping on postoperative day 7 and was successfully treated. The duration of drainage was 2 days and oral intake was started on the seventh day. From our results, we recommend a thoracoscopic procedure through the opposite (right) side chest wall in the early stage of chylothorax development following thoracic aneurysm surgery.

Experimental study on diaphragm fatigue during diaphragm pacing

An experimental study was performed to determine the main site of fatigue associated with diaphragm pacing. Using 24 mature mongrel dogs, weighing 7.5 to 12.7 kg, direct phrenic nerve pacing was conducted from the right cervical area at three different respiration rates, 37 (Group 1, n = 6), 25 (Group 2, n = 6) and 12 (Group 3, n = 6) times per minute, under fixed stimulation conditions (pulse duration, 200 microseconds; frequency, 25 Hz; pulse train repetition time, 1.2 sec). Diaphragm fatigue was defined as the reduction in transdiaphragmatic pressure (Pdi) to less than or equal to 60% of the initial value. In each animal, tidal volume (Vt), induced muscle action potential (Edi), conduction time (CT) and electrical current (E) between two electrodes were examined at various periods until fatigue. In addition, after fatigue, aminophylline (10 mg/kg) was injected and each parameter was observed for an additional 45 min. In 10 animals, the polarity of stimulation was changed from anodal to cathodal current after fatigue and changes in Pdi and Edi were examined. The time to fatigue was 70 +/- 20 min for Group 1, 149 +/- 48 min for Group 2, and 371 +/- 97 min for Group 3, showing a significant stimulation rate dependency (P less than 0.05). Vt and Edi showed a significant decrease (P less than 0.05) at fatigue in all of the groups. However, no significant differences of CT and E were seen between pre- and postfatigue values. Pdi and Edi did not change even when polarity was changed after fatigue. Following administration of aminophylline, Pdi showed a significant (P less than 0.05) increase over time in all groups: 19.8 +/- 13.5% at 5 min, 23.0 +/- 13.5% at 15 min, and 16.2 +/- 14.9% at 30 min for Group 1; 23.6 +/- 11.6% at 5 min, 27.3 +/- 15.5% at 15 min, and 19.0 +/- 16.1% at 30 min for Group 2; and 29.9 +/- 21.1% at 5 min, 29.5 +/- 18.6% at 15 min, 22.3 +/- 13.8% at 30 min, and 15.5 +/- 13.4% at 45 min for Group 3. In contrast, administration of aminophylline caused no significant changes in Edi. Based upon the finding that aminophylline was significantly effective at the time of diaphragm fatigue, it is concluded that fatigue of the muscle itself constitutes one of the contributing factors for the fatigue phenomenon associated with diaphragm pacing.