Abstract-We devised a method of fabricating easily transplantable scaffoldless 3D heart tissue, made with a novel cell-sheet (CS) technology from cultured cardiomyocytes using a fibrin polymer coated dish. In the present study, we tested in vivo electrical communication which is essential for improving heart function between the host heart and the grafted CS. The epicardial surface of the ventricle of an anesthetized open-chest nude rat was ablated by applying a heated metal. Bilayered CS was obtained from neonatal rat primary culture. CS was transplanted onto the injured myocardial surface (sMI) (sMIϩsheet group). The rats were allowed to recover for 1 to 4 weeks, to stabilize the grafts. Action potentials (APs) from the excised perfused heart were monitored by the fluorescence signal of di-4ANEPPS with a high speed charge-coupled device camera. The APs were observed under epicardial pacing of the host heart or the CS grafts. The pacing threshold of the current output was measured in the sMIϩsheet group and in the nongrafted sMI group at the center of the sMI and in the normal zone (Nz). Bidirectional AP propagation between the sMI and Nz was observed in the sMIϩsheet group (nϭ14), but was blocked at the marginal area of the sMI in the sMI group (nϭ9). The ratio of the pacing threshold (sMI/Nz) was significantly lower in the sMIϩsheet than in the sMI group (3.0Ϯ0.7, 19.0Ϯ6.1 respectively PϽ0.05). There were neither spontaneous nor pacing-induced arrhythmias in these two groups. Bidirectional smooth AP propagation between the host heart and the grafted CS was observed. This finding suggested functional integration of this CS graft with the host heart without serious arrhythmia.

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Objective: We analyzed the risk factors for pulmonary metastasis from giant cell tumor of bone and aimed to discuss their therapeutic strategy and appropriate follow-up period. Methods: We analyzed 141 patients of giant cell tumor of bone. The variables analyzed included age, gender, primary site, Campanacci grading, surgical treatment on the primary lesion, radiotherapy and local recurrence. Results: Pulmonary metastasis occurred in 12 patients. The risk factors were young age, Campanacci Grade III and local recurrence. Median time from initial surgery to metastasis was 1.3 years (0-3.1 years). Among them, eight patients experienced local recurrence of the primary tumor, and the median time from initial surgery to local recurrence was 0.8 years (0.3-2.9 years). Among seven patients who underwent wide resection, three patients showed local recurrence of the soft tissue. Nine patients underwent metastasectomy for pulmonary metastases. Of three patients who did not undergo metastasectomy, one patient died of uncontrollable metastases, and two patients showed no changes in their metastatic lesions. Conclusions: Although we found a correlation between local recurrence and pulmonary metastasis, we were still unable to prevent local or metastatic recurrence by wide resection. Local recurrence and metastasis have been found within~3 years after initial surgery, and routine image examinations of the primary site and chest after initial surgical treatment should be considered for at least 3 years postoperatively.

BackgroundDermatofibrosarcoma protuberans (DFSP) may recur locally but rarely metastasizes. Fibrosarcomatous transformation in dermatofibrosarcoma protuberans (FS-DFSP) is said to have worse prognosis compared with ordinary DFSP (O-DFSP). Since DFSP rarely metastasizes, there have been few reports summarizing data on distant metastasis cases at single institution. The aim of this retrospective study is to review DFSP cases in order to analyze risk factors for metastasis.Patients and methodsThis retrospective study involved 67 patients. We analyzed O-DFSP and FS-DFSP metastasis rates, metastasis sites, time to metastasis, the relationship between frequency of local recurrence and metastasis, and the relationship between primary tumor size and metastasis.ResultsDistant metastasis was found in 5 (7.4 %) of 67 cases with DFSP. Of the five cases, the histopathological diagnosis was FS-DFSP in four cases and O-DFSP in one case. Out of five cases with metastasis, three had not recurred and two had recurred twice. No clear correlation was identified (Fisher’s exact test: p = 0.216). The primary tumor diameters in the metastatic cases were 15.0, 12.6, 20.5, 13.0, and 5.0 cm, respectively. The tumor diameters in metastatic cases were significantly larger (Fisher’s exact test: p < 0.0001).ConclusionsIn this study, we identified a stronger correlation between DFSP metastasis and tumor size. There was a high possibility that the cases with large tumors might be FS-DFSP, having high rate of metastasis and poor prognosis. In treatment of DFSP, early diagnosis before primary tumor growth and wide resection is considered important.Level of evidence V.