Takayuki Imakiire

Generation, immunologic characterization and antitumor effects of human monoclonal antibodies for carcinoembryonic antigen

We generated fully human mAbs (HmAbs) to carcinoembryonic antigen (CEA) using the KM mouse, which carries a human chromosome 14 fragment containing the entire Ig H chain loci and human κ L chain segments in the mouse genome. Forty‐six hybridoma clones producing HmAbs to CEA were thus obtained by fusing the P3‐U1 mouse myeloma cells with splenocytes of the KM mice immunized with CEA. Among them, 22 clones produced HmAbs that reacted with CEA but not with 3 other CEA‐related cell adhesion molecule (CEACAM) family members, CEACAM1, CEACAM6 and CEACAM8. In 12 HmAbs examined, 8 were IgG4, 2 were IgG3, 1 was IgG2, and the other was IgG1. The affinity constants for CEA of these HmAbs were comparable to those of the previously prepared mouse anti‐CEA mAbs (MmAbs). BIAcore analyses revealed that 1 and 2 of the 22 HmAbs react with 2 epitopes defined by MmAbs on the domain N and the domain A1 or B1 of CEA, respectively. In the presence of human complement in vitro, 2 HmAbs tested showed substantial cytotoxicity, namely, 50–65%, against CEA‐expressing tumor cells. With human lymphokine‐activated killer cells in vitro, 3 HmAbs tested exhibited 40–65% Ab‐dependent cell‐mediated cytotoxicity against the tumor cells. Moreover, one of the HmAbs induced a significant inhibition of tumor growth when administered to mice xenografted with the CEA‐expressing cells. Considering their lack of immunogenicity to humans, these CEA‐specific HmAbs may be useful for immunotherapeutic approaches as well as for immunodiagnosis.

Preparation of recombinant MK-1/Ep-CAM and establishment of an ELISA system for determining soluble MK-1/Ep-CAM levels in sera of cancer patients.

The MK-1 antigen, also termed as Ep-CAM, is a membrane glycoprotein that is overexpressed on the majority of tumor cells of epithelial origin and thereby can be used as a target of immunodetection and immunotherapy of cancer. It has previously been shown that several type-I transmembrane proteins, including E-cadherin, ErbB-2 and intercellular adhesion molecule-1 (ICAM-1), may be useful as tumor markers because they are released into the circulation of many cancer patients. To address the question of whether MK-1, the same type-I membrane protein, is also released into the sera, we developed a sandwich-type enzyme-linked immunosorbent assay (ELISA) system by preparing a recombinant MK-1 protein and two anti-MK-1 monoclonal antibodies with different epitope specificities. Using this ELISA, we found that the MK-1 levels in serum samples from healthy volunteers were all less than 2 ng/ml, whereas the Mk-1 levels in sera of about 10% of patients with malignant tumors of various tissue origins were increased to 2-78 ng/ml, indicating that MK-1 is released from tumor cells into the circulation under certain conditions. These findings should be borne in mind when trying to perform passive antibody therapy for cancer using anti-MK-1 antibody.

Opposite effects of thrombospondin-1 via CD36 and CD47 on homotypic aggregation of monocytic cells.

Thrombospondin-1 (TSP-1), an extracellular matrix protein, has a multimodular structure and each domain specifies a distinct biological function through interaction with a specific ligand. In this study we found that exogenously added TSP-1 inhibits phorbol myristate acetate (PMA)/LPS-induced homotypic aggregation of human monocytic U937 cells, whereas the 70-kDa fragment of TSP-1 generated by the proteolytic cleavage of the intact molecule promotes the homotypic aggregation. The aggregation was also inhibited by anti-CD47 mAb or the 4N1K peptide, of which sequence is derived from the CD47-binding site of TSP-1 and absent in the 70-kDa fragment. In contrast, the augmented cell aggregation by the 70-kDa fragment was hampered by anti-CD36 mAb or antibody against the CD36-binding site of TSP-1. The cell aggregation of U937 cells was completely blocked, even in the presence of the 70-kDa fragment, by mAb against leukocyte function associated antigen-1 (LFA-1) or intercellular adhesion molecule-1 (ICAM-1). We therefore propose that TSP-1 may regulate LFA-1/ICAM-1-mediated cell adhesion of monocytes/macrophages by either the inhibitory effect through CD47 or the promoting effect through CD36 depending on which domain/fragment is functional in a given biological setting.

Does Pneumothorax Occurrence Correlate with a Change in the Weather

PurposeThere has been speculation that weather changes correlate with the incidence of spontaneous pneumothorax, although this has not been verified. Moreover, there are no significant data available on the meteoropathic pneumothorax in Asia. The aim of this study was to investigate the possible correlation and to compare our results to those of the United States and Europe.MethodsFrom January 2000 to December 2009, 317 spontaneous pneumothorax cases with clear dates of onset were treated in our institution. Using the meteorological data of Fukuoka, Japan, the days with and without an occurrence of pneumothorax were statistically compared in terms of atmospheric pressure, the amount of precipitation, temperature, humidity, hours of sunshine, and occurrence of a typhoon and lightning.ResultsMultivariate analysis revealed that a decrease in the hours of sunshine, an increase in mean temperatures 2 days before the incidence, and the days following a day with lightning were all significantly correlated with the occurrence of pneumothorax (P = 0.2 days before the incidence, and the days following a day with lightning were all significantly correlated with the occurrence of pneumothorax (P = 0.0083, 0.0032, 0.0351, respectively). However, typhoons, as an “unusual” weather condition, did not influence the incidence of pneumothorax (P = 0.983).ConclusionsOur results show strong similarities with reports from European countries despite the different climates. We conclude that the occurrence of pneumothorax appears to correlate with some weather conditions in Japan.

Ten cases of resected solitary pulmonary metastases arising from gastric cancer.

Background Because carcinomatous lymphangitis and carcinomatous pleuritis are the usual forms of metastasis associated with gastric cancer, resection of solitary pulmonary metastases arising from gastric cancer is rarely performed. To clarify the characteristics of pulmonary metastases from gastric cancer, we investigated patients who underwent resection of metastatic solitary lung tumors arising from gastric cancer. Methods Between October 2003 and October 2012, 10 patients underwent pulmonary metastasectomy for metastatic gastric cancer at our institution. We retrospectively evaluated features of the primary gastric cancer and the clinicopathological features of the pulmonary metastases in these cases. Results 70% of the patients had stage II disease. Lymphatic invasion was observed in all cases of primary gastric cancer. The method of pulmonary resection was partial resection in 5 cases, segmentectomy in 1, and lobectomy in 4. On histopathological examination, immunohistochemical staining was negative for thyroid transcription factor-1 and napsin A in all cases. Patients who underwent resection of pulmonary metastases arising from gastric cancer had a good prognosis: the 4-year survival rate was 75%. Conclusions Carefully chosen patients have a good opportunity to obtain benefits from resection of pulmonary metastases arising from gastric cancer.

Prognosis of patients after pulmonary artery plasty for non-small cell lung cancer.

OBJECTIVE We evaluated the clinical outcomes of patients after lung resection with pulmonary artery (PA) plasty for non-small cell lung cancer (NSCLC). METHODS From 1995 to 2006, 36 patients (26 males and 10 females) with NSCLC underwent lobectomy or segmentectomy with PA plasty at our institution. The mean age of the patients was 65.9 years old (range 45-87 years old). There were 17 left upper lobectomies, 10 right upper lobectomies, five left lower lobectomies, two right upper-and-middle bilobectomies, one right lower lobectomy, and one left upper division segmentectomy. Both bronchoplasty and PA plasty were performed in 15 patients. Six patients received preoperative chemotherapy, and one had preoperative radiotherapy. RESULTS The postoperative morbidity rate was 27.8 % (10/36), and the mortality rate (30 days) was 2.8 % (1/36). One patient underwent completion pneumonectomy on postoperative day 13. Macroscopic residual cancer was identified in two patients at the thoracic wall and aorta, respectively; microscopic residual cancers were identified in two patients at the stumps of the pulmonary artery and in one patient at the bronchial stump. Postoperative radiation therapy was additionally given to those four patients, except one. The 5-year survival rate for all patients was 51.8 %. There was no significant difference in the 5-year survival rate between clinical N (cN) 0-1 patients and cN2 patients. However, in pathological N (pN) 0-1 patients, the 5-year survival rate was significantly better than that of pN2 patients (71.9 % versus 0.0 %; P < 0.001). CONCLUSIONS PA plasty for NSCLC is acceptable and highly recommended for pN0-1 patients. Strict patient selection should be considered so as to avoid surgical operations in patients with pN2 staging.

Efficacy of arginine supplementation for the treatment of air leakage.

Background recently, the role of the amino acid arginine in wound healing has been emphasized. We studied whether postoperative enteral arginine supplementation can contribute to the resolution of prolonged air leakage after lung resections. Methods 42 patients undergoing lung resection at our institutions from 2009 to 2012 were enrolled in this study. In these patients, continuous air leakage in the expiratory phase was identified on the day of surgery and on the following day. The patients were divided into 2 groups; the first group included 21 patients consuming 3 packs of an arginine supplement beverage daily postoperatively, and the second group (control) included 21 patients who did not consume any additional supplements. The durations of air leakage and chest tube drainage were compared between the two groups. Results the mean durations of air leakage and chest tube drainage were shorter in the arginine supplementation group (4.4 vs. 6.7 days, p = 0.010; 6.5 vs. 8.3 days, p = 0.042, respectively). Conclusion postoperative enteral arginine supplementation may contribute to stopping air leaks after lung surgery.

Off-the-job training for VATS employing anatomically correct lung models

We evaluated our simulated major lung resection employing anatomically correct lung models as “off-the-job training” for video-assisted thoracic surgery trainees. A total of 76 surgeons voluntarily participated in our study. They performed video-assisted thoracic surgical lobectomy employing anatomically correct lung models, which are made of sponges so that vessels and bronchi can be cut using usual surgical techniques with typical forceps. After the simulation surgery, participants answered questionnaires on a visual analogue scale, in terms of their level of interest and the reality of our training method as off-the-job training for trainees. We considered that the closer a score was to 10, the more useful our method would be for training new surgeons. Regarding the appeal or level of interest in this simulation surgery, the mean score was 8.3 of 10, and regarding reality, it was 7.0. The participants could feel some of the real sensations of the surgery and seemed to be satisfied to perform the simulation lobectomy. Our training method is considered to be suitable as an appropriate type of surgical off-the-job training.

Video-assisted thoracic surgery for lung cancer in hemodialysis patients

Introduction: In recent years, the number of hemodialysis patients has been continuously increasing. At the same time, the use of video‐assisted thoracic surgery (VATS) for lung cancer has also increased. However, reports of the outcome of VATS in hemodialysis patients are still quite rare.

Long‐term patient outcome 10 years after video‐assisted thoracoscopic surgery lobectomy for non‐small‐cell lung cancer

Introduction: Although there have been many reports associating video‐assisted thoracoscopic surgery (VATS) with improved survival rates in early lung cancer, almost all of the reports have involved short median follow‐ups and been presented at a 5‐year point. Here, we establish the pattern and frequency of recurrences, as well as the long‐term survival rates of patients who have undergone VATS more than 10 years ago.