Hiroshi Imano

Akita University Hospital, Akita, Akita, Japan

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Publications (14)43.33 Total impact

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    ABSTRACT: To evaluate magnetic resonance (MR) lymphography with submucosal injection of superparamagnetic iron oxide (SPIO) for imaging lymphatic pathways from thoracic esophageal cancer. In 24 patients with esophageal cancer, SPIO was injected into the submucosal layer of the peritumoral region endoscopically and MR lymphography was conducted. In study 1, fast spoiled gradient-recalled acquisition using a steady-state (FSPGR) sequence was performed from the neck to the upper abdomen before and at 20, 40, and 60 minutes after injection in 10 patients. In study 2, FSPGR and spin echo T1-weighted images were obtained after injection in 14 patients. Areas scanned were the neck to the upper mediastinum and the upper abdomen. In study 1, at 20 minutes after injection, the signal of each lymph node appeared attenuated when compared with precontrast images. The signal-to-noise ratio in lymph nodes exhibiting influx of SPIO was significantly lower than that found on precontrast images (P < 0.0005). In study 2, influx to the neck lymph nodes was detected in 8 patients (64.3%), whereas influx to the upper abdominal lymph nodes was detected in 13 (92.9%). Magnetic resonance lymphography with SPIO could visualize the lymphatic pathways draining from the injection site and the location of lymph nodes exhibiting influx of SPIO in patients with thoracic esophageal cancer.
    Journal of Computer Assisted Tomography 01/2006; 30(2):270-5. · 1.58 Impact Factor
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    ABSTRACT: We report on a case of thoracic esophageal cancer following total gastrectomy (rho-Roux-en-Y reconstruction) with metastasis to the mesojejunal lymph nodes. Subtotal esophagectomy with reconstruction using pedicled colon and dissection of two lymph node fields was performed. During the operation, we found three lymph nodes showing metastasis at the rho-Roux loop of the mesentery, and resected the rho-Roux loop. The route of the lymphatic drainage to the abdomen from the thoracic tumor seemed to have been changed by the prior gastrectomy. Based on the pathological findings, the case was diagnosed with T2N4M0, Stage IVa. We did not confirm that the distant metastases skipped the mesojejunal lymph nodes preoperatively; the distant metastases were detected accidentally by lymphoscintigraphy using technetium-99m tin colloid. We believe this case highlights the need for detailed examinations in esophageal cancer patients who have had prior gastrectomy.
    The Japanese Journal of Thoracic and Cardiovascular Surgery 12/2004; 52(11):542-4.
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    ABSTRACT: The purpose of this study was to detect lymphatic drainage into the superior mediastinum and neck in thoracic esophageal cancer patients using ferumoxides-enhanced magnetic resonance imaging (MRI), and to have this information assist in determining the appropriate extent of lymphadenectomy. Nine male patients with T2-T3 mid- and lower-thoracic esophageal cancer with lymph node metastasis were examined. The day before surgery, ferumoxides was endoscopically injected into the submucosal layer of the peritumoral lesion. Thereafter, lymph nodes in the superior mediastinum and neck, which were shown to be ferumoxides-enhanced on MRI, were harvested and evaluated; magnetic force from all harvested lymph nodes was measured ex vivo. MRI of the superior mediastinum and neck revealed 1(median) ferumoxides-enhanced lymph nodes in eight (89%) patients, and there was laterality in the lymphatic mapping in both areas. Of the 15 lymph nodes into which drainage was detected by enhanced MRI, 12 (80%) were magnetite-positive. In six patients (67%), magnetic resonance enhanced lymph nodes corresponded completely with the ex vivo magnetite examination, and in 3 patients (33%) there was partial agreement. In 3 (60%) of the 5 patients that showed paratracheal and/or supraclavicular lymph node metastases, all of the affected nodes were detected by MRI; in one patient some of the affected nodes were detected. Ferumoxides-enhanced MRI is useful for visualizing lymphatic drainage to the superior mediastinum and neck in thoracic esophageal cancer. It is an adequate procedure to form an estimate on the appropriate extent of lymphadenectomy.
    The Japanese Journal of Thoracic and Cardiovascular Surgery 11/2004; 52(10):445-50.
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    ABSTRACT: We successfully performed off-pump coronary artery bypass grafting (OPCAB) with concomitant esophagectomy in a 77-year-old man with esophageal cancer and severe stenosis of the anterior descending branch of the left coronary artery. Off-pump coronary artery bypass grafting was performed via median sternotomy and esophagectomy was done via the left thoracoabdominal approach. The patient was discharged with a patent graft 8 weeks after surgery. The benefits of OPCAB include that it is less invasive and heparinization can be avoided. This case report demonstrates that simultaneous OPCAB and esophagectomy is advantageous for a selected population with surgically correctable coronary artery disease and resectable esophageal cancer.
    Surgery Today 02/2004; 34(2):156-8. · 0.96 Impact Factor
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    ABSTRACT: The mechanism underlying the immunomodulation caused by blood transfusion has yet to be elucidated. The aim of the present study was to determine whether the transfusion of a soluble or insoluble factor present in stored blood can induce immunomodulation, which would thereby promote solid tumor growth. C57Bl/6J mice were subcutaneously inoculated with B16-CG melanoma cells, which secrete beta-human chorionic gonadotropin (beta-hCG). Following inoculation, each of three different products of allogeneic and syngeneic blood were transfused on days 0 and 1: fresh whole blood, stored whole blood, and supernatants from the stored blood. Tumor growth was then monitored by measuring urinary beta-hCG. All mice were killed on day 15, and the tumor weight and volume were measured. Transfusion of all allogeneic blood products enhanced tumor growth, as did the stored syngeneic whole blood. Neither fresh syngeneic blood nor the supernatant from stored syngeneic blood promoted tumor growth. Although the tumors were not visually detectable until day 10 after inoculation, by day 7 the levels of urinary beta-hCG were significantly higher in the mice that received allogeneic blood supernatant than in the mice that received saline. A soluble alloantigen enhances solid tumor growth, as does an insoluble factor present in stored syngeneic whole blood. The immunomodulation associated with this factor begins to enhance tumor growth within 7 days after transfusion.
    Surgery Today 02/2004; 34(8):673-7. · 0.96 Impact Factor
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    ABSTRACT: The detection rate of sentinel lymph nodes in patients with non-small cell lung cancer using isosulfan blue dye is too low for clinical use. Although exposure to radioactivity is reportedly minimal, special procedures are nonetheless required when a radioactive isotope is used as a tracer. Therefore, to eliminate the need for a radioactive tracer and to obtain a better detection rate than is obtained with isosulfan blue dye, we have developed a novel method that employs magnetite as the tracer. The aim of the present study was to test the feasibility of this technique. The tracer employed was ferumoxides, a colloidal superparamagnetic iron oxide of nonstoichiometric magnetite. Thirty-eight non-small cell lung cancer patients participated in the study; each received 5 mL of ferumoxides, injected around the tumor intraoperatively. Fifteen minutes after injection, lung resection and lymph node dissection were carried out. The magnetic force within the lymph nodes was measured using a highly sensitive handheld magnetometer ex vivo. All lymph nodes were also subjected to conventional histological analysis. The rate of detection of sentinel lymph nodes was 81.6% (31/38). The accuracy, sensitivity, and false-negative rates were 96.8% (30/31), 85.7% (6/7), and 14.3% (1/7), respectively. Intraoperative sentinel lymph node mapping using ferumoxides and a highly sensitive magnetometer is a safe, accurate, and sensitive way to detect sentinel lymph nodes in non-small cell lung cancer patients.
    Journal of Thoracic and Cardiovascular Surgery 09/2003; 126(2):563-7. · 3.53 Impact Factor
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    ABSTRACT: To investigate the mechanism by which methylprednisolone protects the liver from hypoxia-induced injury. Prospective control study using the isolated rat liver. Animal research facility. Male, fasted, pathogen-free Sprague-Dawley rats. Low-flow hypoxia was produced by reducing afferent perfusate pressure from 10 to 2.5 cm H(2)O; isolated livers were portally perfused for 2 hrs. We measured mitochondrial membrane potential and hydrogen peroxide production by imaging rhodamine 123 and 2'-7'-dichlorofluorescein fluorescence, respectively. Leakage of mitochondrial enzymes was also monitored by assaying mitochondrial aspartate aminotransferase activity in the outflow perfusate, and the radical-scavenging effect of methylprednisolone was assessed by measuring luminol-dependent hydrogen peroxide chemiluminescence. Apoptosis in liver cells was determined by using terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling. Rhodamine 123 fluorescence was significantly diminished in the hypoxic liver, especially in the region of the terminal hepatic venules, which is indicative of membrane depolarization in the mitochondria in those areas. Hypoxia-induced mitochondrial dysfunction was indicated by leakage of aspartate aminotransferase into the outflow perfusate, and increased 2'-7'-dichlorofluorescein fluorescence indicated increased hydrogen peroxide levels, particularly in the midzone. Pretreatment with 30, 10, or 3 mg/kg of methylprednisolone inhibited the hypoxia-induced mitochondrial membrane depolarization and enzyme leakage, although hydrogen peroxide levels and apoptosis in sinusoidal endothelial cells were unaffected. Methylprednisolone does not protect the liver from hypoxia-induced injury by suppressing hydrogen peroxide production. Instead, the beneficial effect of methylprednisolone seems to be related to its ability to protect against mitochondrial membrane depolarization under hypoxic conditions.
    Critical Care Medicine 06/2003; 31(5):1468-74. · 6.12 Impact Factor
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    ABSTRACT: Low-flow hypoxia induces xanthine oxidase-dependent hydrogen peroxide production by hepatocytes in the midzone of blood-perfused rat livers and apoptosis in sinusoidal endothelial cells (SECs). As Bcl-2 is a potent inhibitor of apoptotic cell death and is localized mainly in the inner mitochondrial membrane and crista, the purpose of this study was to determine whether cell-specific changes in mitochondrial Bcl-2 levels could account for the hypoxia-induced apoptosis in SECs. A low-flow hypoxia model was generated in isolated rat livers by reducing perfusate inflow pressure from 10 to 2.5 cmH2O for 2 h. Apoptosis was then evaluated using the TdT-mediated dUTP-digoxigenin nick end-labeling (TUNEL) method. Mitochondrial Bcl-2 protein levels were determined in hepatocytes and SECs using cryosectioning immunogold labeling electron microscopy.Results. TUNEL-positive nonparenchymal cells, identified as SECs, were observed predominantly in the midzone of low-flow hypoxic rat livers, whereas few parenchymal cells were stained. Mitochondrial Bcl-2 levels were higher in SECs than in hepatocytes under control conditions, but they declined significantly during hypoxia, though no morphological signs of apoptosis were apparent. In hepatocytes, by contrast, Bcl-2 levels were unaffected by hypoxia. Pretreatment with a specific xanthine oxidase inhibitor, sodium (-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazolo [1,5-a]-1,3,5-triazine-4-olate monohydrate, which blocks production of hydrogen peroxide, also blocked both the hypoxia-induced apoptosis and the decline in mitochondrial Bcl-2 in SECs. Hydrogen peroxide-dependent declines in Bcl-2 induce apoptosis in SECs in the hypoxic rat liver.
    Journal of Surgical Research 04/2003; 110(1):211-6. · 2.02 Impact Factor
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    ABSTRACT: Background. Low-flow hypoxia induces xanthine oxidase-dependent hydrogen peroxide production by hepatocytes in the midzone of blood-perfused rat livers and apoptosis in sinusoidal endothelial cells (SECs). As Bcl-2 is a potent inhibitor of apoptotic cell death and is localized mainly in the inner mitochondrial membrane and crista, the purpose of this study was to determine whether cell-specific changes in mitochondrial Bcl-2 levels could account for the hypoxia-induced apoptosis in SECs.Materials and methods. A low-flow hypoxia model was generated in isolated rat livers by reducing perfusate inflow pressure from 10 to 2.5 cmH2O for 2 h. Apoptosis was then evaluated using the TdT-mediated dUTP-digoxigenin nick end-labeling (TUNEL) method. Mitochondrial Bcl-2 protein levels were determined in hepatocytes and SECs using cryosectioning immunogold labeling electron microscopy.Results. TUNEL-positive nonparenchymal cells, identified as SECs, were observed predominantly in the midzone of low-flow hypoxic rat livers, whereas few parenchymal cells were stained. Mitochondrial Bcl-2 levels were higher in SECs than in hepatocytes under control conditions, but they declined significantly during hypoxia, though no morphological signs of apoptosis were apparent. In hepatocytes, by contrast, Bcl-2 levels were unaffected by hypoxia. Pretreatment with a specific xanthine oxidase inhibitor, sodium (-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazolo [1,5-a]-1,3,5-triazine-4-olate monohydrate, which blocks production of hydrogen peroxide, also blocked both the hypoxia-induced apoptosis and the decline in mitochondrial Bcl-2 in SECs.Conclusion. Hydrogen peroxide-dependent declines in Bcl-2 induce apoptosis in SECs in the hypoxic rat liver.
    Journal of Surgical Research - J SURG RES. 01/2003; 110(1):211-216.
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    ABSTRACT: To determine whether the clinical presentation of pulmonary edema following esophagectomy can be objectively determined by changes in X-ray density in the lung field on chest radiography. Sixteen patients who underwent esophagectomy for thoracic esophageal cancer and five patients who underwent less radical surgery at Akita University Hospital between July 2000 and March 2001 were recruited to the thoracic esophageal cancer and control groups, respectively. Chest radiography was carried out using five aluminum disks (15, 20, 25, 30 and 35 mm thickness) placed in upper right corner of the film and X-ray density for the disks and chest lung field was measured using a densitometer until POD 7. In the thoracic esophageal cancer group, X-ray density in the lung field, body weight, and respiratory index increased significantly in the immediate postoperative period. The X-ray density in the lung field peaked on POD 2, and remained constant to POD 6. Correlations were found among changes in X-ray density in the lung field, body weight, and respiratory index. The measurement of X-ray density on a chest radiograph is useful for prediction as well as early management of patients with pulmonary edema following esophagectomy for thoracic esophageal cancer.
    Hepato-gastroenterology 01/2003; 50(53):1403-6. · 0.77 Impact Factor
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    ABSTRACT: Recent advances in the treatment of esophageal cancer have afforded better prognosis for patients. Despite the increased need to monitor the progress of patients with reconstructed digestive tracts over the long-term, no reliable prospective studies have yet been conducted. This prospective study determined secondary disease of the reconstructed gastric tube after esophagectomy for esophageal cancer. One hundred and fourteen patients who underwent esophagectomy and reconstructed gastric tube via the posterior mediastinal route between April 1992 and March 1999 at Akita University Hospital, were followed up. Follow-up endoscopy was carried out once a year to determine the incidence and characteristics of secondary disease of the reconstructed gastric tube. Fifty-four (47%) patients were found to have secondary gastric abnormalities. Of these, 4 patients (3.5%) had carcinoma of the gastric tube, 12 patients (10.5%) had benign gastric tumor, 7 patients (6.1%) had gastric ulcers, and 40 patients (35.1%) had erosive or hemorrhagic gastritis. Three patients found to have early gastric cancer upon periodic follow-up endoscopy underwent successful complete resections. Annual follow-up endoscopy is vital to the detection of early, curative secondary gastric cancer and ulceration in patients following esophagectomy for esophageal cancer.
    Hepato-gastroenterology 01/2003; 50(51):666-9. · 0.77 Impact Factor
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    ABSTRACT: There is evidence that blood transfusion is associated with an increased rate of tumor recurrence. This study was conducted to assess the survival advantage of giving autologous blood instead of allogeneic blood during surgery for esophageal cancer. We retrospectively analyzed 62 patients who underwent esophagectomy for thoracic esophageal cancer between January 1991 and February 1995 and received allogeneic blood transfusion, and 61 patients operated on between March 1995 and February 1998, who received autologous blood transfusion. The clinicopathological factors and survival rates were compared between the two groups. The clinicopathological factors that influenced prognosis were similar in the two groups; however, a definite survival advantage was evident in the autologous blood transfusion group. According to multivariate analyses, the transfusion of allogeneic blood was an independent prognostic factor ( P = 0.0222), as was the presence of metastatic lymph nodes. Patients who received allogeneic blood transfusions perioperatively had more than a twofold greater risk (Hazard ration 2.406) of death over patients who received autologous blood transfusions. Autologous blood transfusion appears to be an independent prognostic factor for the survival of patients with esophageal cancer.
    Surgery Today 02/2002; 32(11):951-8. · 0.96 Impact Factor
  • Gastroenterology 01/2001; 120(5). · 12.82 Impact Factor
  • Gastroenterology 01/2001; 120(5). · 12.82 Impact Factor