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Ichiro Oda

Publications and source records attributed to Ichiro Oda.

At least 19 recordsLinked to original sources
PubMed2006

Metachronous gastric cancers after endoscopic resection: how effective is annual endoscopic surveillance?

BACKGROUND: Endoscopic resection (ER) has been widely accepted in Japan as a less invasive treatment for early gastric cancer, but the incidence of subsequent metachronous gastric cancer (MGC) and the appropriate endoscopic follow-up interval after ER have not been determined as yet. In this study, we investigated the incidence of MGC after ER and assessed our annual endoscopic surveillance program after ER. METHODS: We studied the clinicopathological features of 633 consecutive ER patients (575 with a single lesion and 58 with synchronous multiple lesions) treated at our institution from 1987 through 2002, after excluding 158 patients who underwent additional surgery due to noncurative ERs, 180 patients whose surveillance periods were less than 1 year, 1 patient with hereditary non-polyposis colorectal cancer, and 1 patient with gastric tube cancer. We defined a second cancer found within 1 year after ER as "synchronous" and a second cancer found after 1 year as "metachronous." RESULTS: First MGCs had an overall incidence of 8.2% (52 out of 633 patients); the annual incidence was constant, and the cumulative 3-year incidence was 5.9%. The average time to the discovery of a first MGC after the initial ER was 3.1 +/- 1.7 years (range, 1-8.6 years). Almost all first MGCs (96.2%, 50 out of 52 lesions) were treated curatively with repeat ER. CONCLUSION: In order to detect MGC at a stage early enough for a curative repeat ER, an annual endoscopic surveillance program is both practical and effective for post-ER patients.

Adult↗
PubMed2006

Complete endoscopic closure of gastric perforation induced by endoscopic resection of early gastric cancer using endoclips can prevent surgery (with video).

BACKGROUND: When gastric perforation occurs during endoscopic resection for early gastric cancer, a surgical treatment generally is performed. Considering the increasing number of EMRs and the possibility of perforation, our research sought to investigate whether endoscopic treatment for gastric perforation is possible. METHODS: From 1987 to 2004, 121 of 2460 patients who underwent gastric EMR at the National Cancer Center Hospital had gastric perforation during EMR (4.9%). The initial 4 patients were treated with emergent surgery. The subsequent 117 patients who were treated with endoclips formed our study population. RESULTS: Endoscopic closure with endoclips in 115 patients (98.3%) was successful. Two patients with unsuccessful endoscopic closure underwent emergent surgery. In the past 6 years, patients with perforation during gastric EMR treated with endoscopic closure had a recovery rate similar to that of the nonperforation cases. CONCLUSIONS: Gastric perforation during endoscopic resection can be conservatively treated by complete endoscopic closure with endoclips.

Adult↗
PubMed2006

Endoscopic submucosal dissection allows curative resection of locally recurrent early gastric cancer after prior endoscopic mucosal resection.

BACKGROUND: Repeat endoscopic mucosal resection (EMR) to cure locally recurrent early gastric cancer (EGC) is difficult to perform because the initial EMR causes submucosal fibrosis; however, ESD allows submucosal dissection through the fibrosis and provides an en bloc specimen. OBJECTIVE: The objective was to determine the safety and efficacy of ESD and compare the results to historical controls. DESIGN: This was a retrospective, case-control study. PATIENTS: We used our prospectively entered database (1993-2003) to identify 64 patients who had locally recurrent EGC after EMR. MAIN OUTCOME MEASUREMENTS: We defined the resections as curative when the lateral and vertical margins were free of cancer and repeat endoscopy showed no recurrent disease. RESULTS: Among 46 patients who underwent ESD, 41 (89.1%) en bloc resections were achieved compared to none in 18 conventional procedures (P < .0001). The specimen of 1 lesion (2.4%) out of 41 en bloc resections was histologically nonevaluable, compared with 10 lesions (43.4%) in 23 piecemeal resections (P < .0001). Three residual tumors (27.3%) were found in the 11 nonevaluable specimens. Three perforations occurred during ESD; all were successfully treated endoscopically with endoclips. LIMITATIONS: The limitation of the study was retrospective design. CONCLUSIONS: ESD provides high en bloc resection rate for locally recurrent EGC after previous EMR. In turn, en bloc resections allow precise histological staging to be assessed and prevent residual disease and recurrence.

Aged↗
PubMed2006

Epstein-Barr virus involvement is a predictive factor for the resistance to chemoradiotherapy of gastric diffuse large B-cell lymphoma.

Primary gastric diffuse large B-cell lymphomas are generally well controlled by non-surgical treatment with combination chemotherapy followed by radiotherapy. We have previously reported that over 90% of patients achieved complete response (CR) with this therapeutic strategy: three cycles of cyclophosphamide, adriamycin, vincristine and prednisone followed by radiotherapy (40.5 Gy). Although the CR rate was very high, some patients still showed resistance to this combination therapy. In order to clarify the factors related to therapy resistance, we examined the relationship between Epstein-Barr virus (EBV), which was examined using an in situ hybridization technique, and the patients' clinical courses. Out of the 50 patients, four were EBV positive; over half of lymphoma cells were positive for EBV by in situ hybridization. Of the three EBV-positive patients, two showed progressive disease and one achieved partial response (PR). Two of the patients died of disease progression. The other patient achieved CR, but the lymphoma recurred with distant metastasis in the cerebellum 3 months after remission. In the present study, eight patients did not achieve CR or they relapsed, four patients showed progressive disease, one patient achieved PR, and three patients achieved CR with recurrence. Therefore, half of these unfavorable patients were EBV positive. This finding strongly indicated that EBV-associated gastric diffuse large B-cell lymphomas frequently show resistance to standard chemoradiotherapy, although some other adverse factors remain unclear.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Higher methylation levels in gastric mucosae significantly correlate with higher risk of gastric cancers.

BACKGROUND: Helicobacter pylori infection potently induces methylation of CpG islands in gastric mucosae, which is considered to decrease to a certain level after active H. pylori infection discontinues. Noncancerous gastric mucosae of H. pylori-negative cases with a gastric cancer had higher methylation levels than those of H. pylori-negative healthy individuals. Here, using cases with multiple gastric cancers, we analyzed whether the higher methylation levels correlated with the higher risk of gastric cancers. METHODS: Twenty-six healthy volunteers (HV), 30 cases with a single well-differentiated gastric cancer (S cases), and 32 cases with multiple well-differentiated gastric cancers (M cases) were recruited. H. pylori infection status was analyzed by the culture method. Methylation levels were quantified by real-time methylation-specific PCR of seven CpG islands. RESULTS: In H. pylori-negative individuals, significant increasing trends were present in the order of HV, S cases, and M cases for FLNc and HAND1 methylation levels (P < 0.01, Spearman's rank-order test). Furthermore, the FLNc methylation level of M cases was significantly higher than that of S cases (P < 0.01, t test). Even adjusted by the extent of gastric atrophy, the FLNc methylation level retained a significant increasing trend (P = 0.03). In contrast, methylation levels in H. pylori-positive individuals were increased to various degrees in all the three groups. CONCLUSIONS: In H. pylori-negative individuals, methylation levels in gastric mucosae significantly increased in cases with a single gastric cancer and more in cases with multiple gastric cancers. Quantitative analysis of methylation levels is a promising risk marker for gastric cancers.

Aged↗
PubMed2005

A flexible endoscopic surgical system: first report on a conceptual design of the system validated by experiments.

BACKGROUND: Surgery is a standard diagnostic and therapeutic procedure. However, its technical difficulty and invasiveness pose problems that are yet to be solved even by current surgical robots. Flexible endoscopes can access regions deep inside the body with less invasiveness than surgical approaches. Conceptually, this ability can be a solution to some of the surgical problems. METHODS: A flexible (surgical) endoscopic surgical system was developed consisting of an outer and two inner endoscopes introduced through two larger working channels of the outer endoscope. The concept of the system as a surgical instrument was assessed by animal experiments. RESULTS: Gastric mucosa of the swine could be successfully resected using the flexible endoscopic surgical system, thereby showing us the prospect and directions for further development of the system. CONCLUSION: The concept of a flexible endoscopic surgical system is considered to offer some solutions for problems in surgery.

Animals↗
PubMed2005

Distribution of the deepest penetrating point of minute submucosal gastric cancer.

BACKGROUND: Accurate assessment of depth of invasion is critical in decision-making for additional surgery after endoscopic resection of early gastric cancer (EGC). Although this depth of invasion is determined at the deepest point of submucosal invasion (DPSI), there is no literature describing the distribution of deepest invasion point. OBJECTIVE: To describe the location of the DPSI, and to determine whether it is possible to predict this point by clinicopathological features before treatment. METHODS: One hundred and ninety-five lesions of EGC with minute submucosal invasion, which had been resected en bloc between 1991 and 2003, were reviewed. For each lesion, we recorded the location of the DPSI as being in one of three areas demarcated by three concentric equal distance rings. We also examined the correlation between the location of the deepest penetration and the clinicopathological characteristics. RESULTS: The DPSI was located most often (53%) in the central, less often (31%) in the middle and least often (16%) in the outermost area. There was no significant correlation between the distribution of the deepest point and any clinicopathological features. CONCLUSIONS: The DPSI was not always in the central area, and it was impossible to predict its location by clinicopathological features alone. To obtain an accurate measure of depth of tumor invasion, we must histologically assess the entire lesion by thin sections.

Adenocarcinoma↗
PubMed2005

Treatment of early gastric cancer in the elderly patient: results of EMR and gastrectomy at a national referral center in Japan.

BACKGROUND: The Japanese population is rapidly aging, and the actual number of elderly patients with gastric cancer, including early cancer, has been increasing, even though the standardized incidence of gastric cancer in the population is decreasing. The optimal treatment for these patients remains a challenge to the surgeon. The aim of this retrospective analysis was to describe the results of gastrectomy and EMR for early gastric cancer in elderly patients (80 years of age and over). METHODS: This is a retrospective review of 93 elderly patients who had undergone gastrectomy or EMR at the National Cancer Center Hospital for early gastric cancer. EMR was performed aiming en bloc local resection with a clear curative margin (R0). The clinicopathologic characteristics, comorbidity, postoperative mortality, and outcome were recorded. RESULTS: Gastrectomy was performed in 44 patients (surgery group) and EMR in 49 patients (EMR group). There were significant differences in mean tumor size (p < 0.05), histologic type (p < 0.05), and depth of tumor invasion (p < 0.05) between the two groups. There was no significant difference in comorbidity between the two groups. No operative death was reported in either group. In the EMR group, 7 patients were reported to have recurrence of local disease and two patients died of advanced disease. There were no significant differences in the overall 3-year survival rate or the 5-year survival rate between the surgery group and EMR group (73.5% vs. 82.5% and 55.0% vs. 62.5%, respectively). CONCLUSIONS: EMR (R0) resection was performed safely in the elderly, and the overall results were excellent, the same as the results with gastrectomy. Gastrectomy can still be performed if EMR is unsuccessful.

Aged↗
PubMed2005

Japanese multicenter phase II study of CHOP followed by radiotherapy in stage I-II, diffuse large B-cell lymphoma of the stomach.

CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) followed by radiotherapy is regarded as standard care for localized aggressive lymphoma; however, prospective confirmation of its applicability to localized primary gastric lymphoma is inadequate, and most patients in Japan have been initially treated with gastrectomy. We conducted a multicenter phase II study to evaluate the feasibility and efficacy of the non-surgical treatment. Eligibility criteria required primary gastric diffuse large B-cell lymphoma, stage I-II(1), age 20-75, performance status 0-1 and adequate organ function. Treatment consisted of three cycles of CHOP followed by radiotherapy 40.5 Gy. Fifty-five patients were enrolled between December 1999 and February 2003, and 52 eligible patients were analyzed. Patient characteristics were as follows: median age, 61 years; 28 men, 24 women; 36 with stage I, 16 with stage II(1); 47 with a low International Prognostic Index (IPI) and five with a low-intermediate IPI. All but one patient completed planned treatment. No serious complications including massive hemorrhage or perforation were observed. A complete response was achieved in 48 of the 52 patients (92%, 95% confidence interval: 82-98%) and progressive disease in three. Two patients underwent salvage gastrectomy due to disease persistence or recurrence. With a median follow-up period of 28 months, 2-year progression-free and overall survivals were 88 and 94%, respectively. CHOP followed by radiotherapy is safe and highly effective in localized gastric diffuse large B-cell lymphoma. This organ-preserving treatment should be considered as a very reasonable therapeutic option.

Administration, Oral↗
PubMed2004

The parietal role in the sense of self-ownership with temporal discrepancy between visual and proprioceptive feedbacks.

One hypothesis on how we recognize an image of, for example, an arm as our own is through the co-occurrence of multiple sensory feedbacks, especially visual and proprioceptive feedbacks, in this process. It has been suggested that the parietal lobe is the region where proprioceptive and visual information of one's own body is integrated. This study investigated parietal cortical activity during a visual-proprioceptive synchrony judgment task in which visual feedback of the subjects' own passively moving hand was delayed. The subjects were required to judge whether or not there was a delay between the proprioceptive and visual feedbacks. Parietal cortical activity, which was measured using a 48-channel near-infrared spectroscopy (NIRS) apparatus, appeared to be modulated by the length of the delay between the visual and proprioceptive feedbacks. The bilateral superior/middle parietal areas were involved in experiencing the synchrony between the visual and proprioceptive feedbacks, whereas the right inferior parietal areas were strongly activated when discrepancy between the two feedbacks was detected. We postulate that the superior portion of the parietal lobe is essential for maintaining one's own body image, while the right inferior portion is involved in detecting movements of others.

Adolescent↗
PubMed2004

Decrease in prefrontal hemoglobin oxygenation during reaching tasks with delayed visual feedback: a near-infrared spectroscopy study.

Visual feedback of hand movement is crucial to accurate reaching. Although previous studies have extensively examined spatial alteration of visual feedback (e.g., prism adaptation), temporal delay of visual feedback has been less explored. In the present study, we investigated the effect of delayed visual feedback of the moving hand in a reaching task. The prefrontal cortical activity was measured by near-infrared spectroscopy (NIRS). Twelve subjects performed reaching tasks under two conditions where visual feedback of their own hand was delayed by 200 ms (delay condition) or 0 ms (normal condition). Introducing the visual feedback delay significantly disrupted the reaching performance, although the subjects gradually adapted to the delay during the experiment. There was a clear tendency to overreach the target in the delay condition, even after the reaching movement had been practiced sufficiently in the normal condition. We observed marked oxy- and total-Hb decreases in the dorsal prefrontal area in the delay conditions. The decrease began shortly after task onset and diminished during the rest period, indicating that the decrease was task-induced. Furthermore, the oxy- and total-Hb decreases were significantly correlated with task performance--the degree of decrease was larger as the subject made more errors. We suggest that the decreases in oxy- and total-Hb at the dorsal prefrontal area are related with the visuomotor recalibration process.

Adult↗
PubMed2004

Three-dimensional probabilistic anatomical cranio-cerebral correlation via the international 10-20 system oriented for transcranial functional brain mapping.

The recent advent of multichannel near-infrared spectroscopy (NIRS) has expanded its technical potential for human brain mapping. However, NIRS measurement has a technical drawback in that it measures cortical activities from the head surface without anatomical information of the object to be measured. This problem is also found in transcranial magnetic stimulation (TMS) that transcranially activates or inactivates the cortical surface. To overcome this drawback, we examined cranio-cerebral correlation using magnetic resonance imaging (MRI) via the guidance of the international 10-20 system for electrode placement, which had originally been developed for electroencephalography. We projected the 10-20 standard cranial positions over the cerebral cortical surface. After examining the cranio-cerebral correspondence for 17 healthy adults, we normalized the 10-20 cortical projection points of the subjects to the standard Montreal Neurological Institute (MNI) and Talairach stereotactic coordinates and obtained their probabilistic distributions. We also expressed the anatomical structures for the 10-20 cortical projection points probabilistically. Next, we examined the distance between the cortical surface and the head surface along the scalp and created a cortical surface depth map. We found that the locations of 10-20 cortical projection points in the standard MNI or Talairach space could be estimated with an average standard deviation of 8 mm. This study provided an initial step toward establishing a three-dimensional probabilistic anatomical platform that enables intra- and intermodal comparisons of NIRS and TMS brain imaging data.

Adult↗
PubMed2004

Multimodal assessment of cortical activation during apple peeling by NIRS and fMRI.

An intriguing application of neuroimaging is directly measuring actual human brain activities during daily living. To this end, we investigated cortical activation patterns during apple peeling. We first conducted a pilot study to assess the activation pattern of the whole lateral cortical surface during apple peeling by multichannel near-infrared spectroscopy (NIRS) and detected substantial activation in the prefrontal region in addition to expected activations extending over the motor, premotor and supplementary motor areas. We next examined cortical activation during mock apple peeling by simultaneous measurement using multichannel NIRS and functional magnetic resonance imaging (fMRI) in four subjects. We detected activations extending over the motor, premotor and supplementary motor areas, but not in the prefrontal cortex. Thus, we finally focused on the prefrontal cortex and examined its activation during apple peeling in 12 subjects using a multichannel NIRS. We subsequently found that regional concentrations of oxygenated hemoglobin significantly increased in the measured region, which encompassed portions of the dorsolateral, ventrolateral and frontopolar areas of the prefrontal cortex. The current study demonstrated that apple peeling as practiced in daily life recruited the prefrontal cortex but that such activation might not be detected for less laborious mock apple peeling that can be performed in an fMRI environment. We suggest the importance of cortical study of an everyday task as it is but not as a simplified form; we also suggest the validity of NIRS for this purpose. Studies on everyday tasks may serve as stepping stone toward understanding human activities in terms of cortical activations.

Activities of Daily Living↗
PubMed2004

Prefrontal and premotor cortices are involved in adapting walking and running speed on the treadmill: an optical imaging study.

We investigated changes of regional activation in the frontal cortices as assessed by changes of hemoglobin oxygenation during walking at 3 and 5 km/h and running at 9 km/h on a treadmill using a near-infrared spectroscopic (NIRS) imaging technique. During the acceleration periods immediately preceded reaching the steady walking or running speed, the levels of oxygenated hemoglobin (oxyHb) increased, but those of deoxygenated hemoglobin (deoxyHb) did not in the frontal cortices. The changes were greater at the higher locomotor speed in the bilateral prefrontal cortex and the premotor cortex, but there were less speed-associated changes in the sensorimotor cortices. The medial prefrontal activation was most prominent during the running task. These results indicate that the prefrontal and premotor cortices are involved in adapting to locomotor speed on the treadmill. These areas might predominantly participate in the control of running rather than walking.

Acceleration↗
PubMed2004

Percutaneous traction-assisted EMR by using an insulation-tipped electrosurgical knife for early stage gastric cancer.

BACKGROUND: EMR now is accepted as a minimally invasive treatment for early stage gastric cancer. However, the endoscopic approach sometimes is limited by the size and location of the tumor. The technique and early results of percutaneous, traction-assisted EMR for resection of larger early stage gastric cancers is described. METHODS: EMR, by using an insulation-tipped electrosurgical knife, was performed with the simultaneous assistance of laparoscopy devices. A small snare was introduced into the gastric lumen through a gastric port (2-mm diameter) to grasp and pull the EGC away from the muscularis propria to facilitate resection. RESULTS: The technique was performed successfully in our endoscopic suite in the first patient under general anesthesia and the remaining seven under conscious sedation. Tumors situated in any part of the stomach could be reached with percutaneous assistance, and this facilitated en bloc resection of large specimens (mean size 50 mm). The procedure was performed in about 60 minutes. Seven patients (88%) resumed eating 1 or 2 days after surgery. All patients were discharged after 1 week without complication. CONCLUSIONS: Percutaneous, traction-assisted EMR is useful for resection of large lesions en bloc and can be performed easily and safely under direct vision.

Adult↗
PubMed2003

Longitudinal optical imaging study for locomotor recovery after stroke.

BACKGROUND AND PURPOSE: We sought to investigate cerebral mechanisms underlying locomotor recovery after stroke. METHODS: We measured cortical activities during hemiparetic gait on the treadmill before and after 2 months of inpatient rehabilitation in 8 patients with initial stroke (5 men, 3 women; 4 with right and 4 with left hemiparesis; aged 57 years; 3 months after stroke on average), using an optical imaging system. RESULTS: On the initial evaluation, hemiparetic gait was associated with increased oxygenated hemoglobin levels in the medial primary sensorimotor cortex (SMC) that were greater in the unaffected hemisphere than in the affected hemisphere as well as in the premotor cortex (PMC) and supplementary motor area. On the second examination, the asymmetry in SMC activation significantly improved, and there was enhanced PMC activation in the affected hemisphere. Improvement of the asymmetrical SMC activation significantly correlated with improvement of gait parameters. CONCLUSIONS: Locomotor recovery after stroke may be associated with improvement of asymmetry in SMC activation and enhanced PMC activation in the affected hemisphere.

Adult↗
PubMed2003

Spatiotemporal characteristics of hemodynamic changes in the human lateral prefrontal cortex during working memory tasks.

The prefrontal cortex (PFC) is widely believed to subserve mental manipulation and monitoring processes ascribed to the central executive (CE) of working memory (WM). We attempted to examine and localize the CE by functional imaging of the frontal cortex during tasks designed to require the CE. Using near-infrared spectroscopy, we studied the spatiotemporal dynamics of oxygenated hemoglobin (oxy-Hb), an indicator of changes in regional cerebral blood flow, in both sides of lateral PFC during WM intensive tasks. In most participants, increases in oxy-Hb were localized within one subdivison during performance of the n-back task, whereas oxy-Hb increased more diffusely during the random number generation (RNG) task. Activation of the ventrolateral PFC (VLPFC) was prominent in the n-back task; both sustained and transient dynamics were observed. Transient dynamics means that oxy-Hb first increases but then decreases to less than 50% of the peak value or below the baseline level before the end of the task. For the RNG task sustained activity was also observed in the dorsolateral PFC (DLPFC), especially in the right hemisphere. However, details of patterns of activation varied across participants: subdivisions commonly activated during performance of the two tasks were the bilateral VLPFCs, either side of the VLPFC, and either side of the DLPFC in 4, 2, and 4 of the 12 participants, respectively. The remaining 2 of the 12 participants had no regions commonly activated by these tasks. These results suggest that although the PFC is implicated in the CE, there is no stereotyped anatomical PFC substrate for the CE.

Adult↗