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Biomedical subjects

Takuya Yamada

Publications and source records attributed to Takuya Yamada.

10 recordsLinked to original sources
PubMed2006

Longterm outcomes after endoscopic mucosal resection for early gastric cancer.

BACKGROUND: Despite the widespread use of endoscopic mucosal resection (EMR) in patients with early gastric cancer (EGC), its longterm outcomes have not been fully evaluated. Our aim was to evaluate longterm survival after complete EMR for EGC. METHODS: From patients who underwent EMR between 1978 and 1996 at our center, we enrolled 131 patients with differentiated mucosal EGCs less than 2 cm (without ulcerative change) that had been completely removed by EMR. The vital status of the patients at the end of December 1998 was confirmed by the hospital cancer registry, which is linked to the Osaka Cancer Registry. RESULTS: A total of 124 patients (95%) were completely followed-up. Two patients (1.5%) died of gastric cancer and 26 died of other causes during the mean observation period of 58 months. The overall 5- and 10-year survival rates were 84% and 64%, respectively. The disease-specific 5- and 10-year survival rates were 99% and 99%. CONCLUSION: En bloc EMR ensured an excellent prognosis, and should be the first choice of treatment in patients with small differentiated mucosal EGC. Careful histological examination and longterm endoscopic surveillance are important.

Adenocarcinoma↗
PubMed2005

Simultaneous operation of ischemic heart disease, abdominal aortic aneurysm, and rectal cancer.

A 68-year-old man with ischemic heart disease, abdominal aortic aneurysm, and rectal cancer was referred. Coronary angiography indicated triple-vessel disease with jeopardized collaterals, and dipyridamole myocardial scintigraphy disclosed no viability in the inferior, posterior, and lateral walls. Abdominal computed tomography scanning revealed an infrarenal abdominal aortic aneurysm, 65 mm in diameter, with an expanding rate of 8 mm/year. Barium enema revealed stenosis 4 cm in length 5 cm inward from the anal verge, and an endoscopic finding was ulcerated type tumor with a clear margin and circumferential stenosis. Histological examination of a biopsy specimen revealed adenocarcinoma, and the clinical stage in the Japanese classification of colorectal carcinoma was II according to other examinations. Simultaneous operations were scheduled because of the jeopardized collaterals of the coronary arteries, rapid expansion of the aneurysm, and subileus due to the cancer. The patient underwent simultaneous off-pump coronary artery bypass grafting to the left anterior descending artery with the in situ internal thoracic artery through a median sternotomy, abdominal aortic aneurysm repair with a tube graft through a median laparotomy, and the Miles' operation with total mesorectal excision. Although infection of the perineal wound was postoperatively recognized, it remained local and was healed with irrigation only. The patient is doing well 12 months after the operation, without myocardial ischemic symptoms or recurrence of the cancer.

Adenocarcinoma↗
PubMed2005

A novel videoendoscopy system by using autofluorescence and reflectance imaging for diagnosis of esophagogastric cancers.

BACKGROUND: Image quality of the prior autofluorescence (AF) imaging systems, including the fiber-optic endoscope, was not feasible for general clinical use. The use of AF image alone resulted in low specificity. The objective of the study was to evaluate the resolution and the sensitivity of the novel videoendoscopy system by using AF and reflectance imaging (AFI) in the diagnosis of early esophagogastric cancers. METHODS: This was a case series study. The setting was a pretreatment examination at a cancer center. Five patients with superficial esophageal cancers (SEC) and 21 patients with 22 early gastric cancers (EGC) were included in the study. The extent of the tumors was diagnosed by white light (WL), AF and chromoendoscopic observations. The main outcome measurement was the diagnostic accuracy of each observation in relation to the histologic mapping as a criterion standard. RESULTS: Two of 5 SECs (40%) were correctly diagnosed in the WL image and all (100%) in the AF image as purple or magenta color in a green background. EGCs in atrophic mucosa were observed as purple or magenta areas in a green background, while diffuse-type EGCs in fundic mucosa were observed as green areas in a purple background. Of the 22 EGCs, diagnostic accuracy of WL, AF, and chromoendoscopic observations were 36%: 95% CI [16%, 56%], 68%: 95% CI [49%, 88%], and 91%: 95% CI [79%, 100%], respectively. AFI could reveal flat or isochromatic extensions that were not detected in the WL images. The limitations of the study were ulcerations or inflammation that caused overdiagnosis in the AF observation. CONCLUSIONS: The resolution of the AFI at present is limited, but the image quality was acceptable. The current system of AFI does not equal to chromoendoscopy in sensitivity but has an advantage over standard WL videoendoscopy.

Aged↗
PubMed2004

Translocation of Salmonella typhimurium in rats on total parenteral nutrition correlates with changes in intestinal morphology and mucus gel.

OBJECTIVE: We tested whether alterations in intestinal morphology and mucus gel correlate with differences in Salmonella typhimurium translocation between rats treated with total parenteral nutrition (TPN) and rats given a diet of chow. METHODS: Twenty-seven male Wistar rats were assigned to one of two groups: one received TPN for 14 d and the other (control) received standard rat chow and water ad libitum. Salmonella typhimurium (5 x 10(8) cells; GIFU 12142) was injected into a closed ileal loop. Portal venous blood (PVB), inferior vena cava blood (IVCB), and mesenteric lymph nodes (MLNs) were sampled for evaluation of bacterial translocation. Sections of the loop were prepared and stained with hematoxylin and eosin, periodic acid-Schiff (PAS), and fluorescein isothiocyanate-labeled Ulex europaeus agglutinin I (FITC-UEA-I) for image analysis. Perimeter, mucosal thickness, villus area, and positively stained mucus area were measured. A fluorescent antibody study was also done. RESULTS: Organisms were found in cultures of 1 in 13 control rats and 9 in 14 TPN rats. There were more bacteria in MLNs than in PVB or IVCB. There was no increase in the number of bacteria over time in PVB, IVCB, or MLNs. Perimeter and villus area (P < 0.001) and mucosal thickness (P < 0.01) were significantly smaller in the TPN group than in the control group. The positively stained mucus area was significantly smaller in the TPN group than in the control group (P < 0.05 with PAS, P < 0.01 with FITC-UEA-I). Salmonella typhimurium invaded specifically through Peyer's patches. In all culture-negative samples, bacteria were trapped by the mucous layer, with a very small number attached to the epithelial surface. CONCLUSION: Significant villous atrophy and reduction of mucus play an important role in the rapid translocation of S. typhimurium through Peyer's patches in rats after 2 wk of TPN.

Animals↗
PubMed2004

Experimental studies to estimate the intestinal viability in a rat strangulated ileus model using a dielectric parameter.

This study aimed at establishment of adequate evaluation of intestinal viability before release of the strangulated intestine by measuring electrical properties. In rats a 20-cm segment of the distal ileum and mesentery was strangulated. The intestine was strangulated for 0, 2, 15, 45, 90, and 120 min. The conductance and capacitance obtained by impedance analyzer were used to calculate tan(delta)m in the strangulated intestine. ATP was measured as well. In another experiment, after various periods of strangulation, tan(delta)m was measured just before release of the strangulation. Rats were divided into Group A (survived for 7 days) and Group D (died within 7 days). There was a positive correlation between tan(delta)m and ATP levels (P < 0.01). And tan(delta)m was significantly greater in Group A than in Group D (P < 0.05). There were no deaths at a tan(delta)m value of 2.36 or more and no survivors at a tan(delta)m of less than 2.20 except for one rat. These results suggested that tan(delta)m may be a useful index of the viability of the strangulated intestine before reperfusion.

Adenosine Triphosphate↗
PubMed2003

Simultaneous operations for abdominal aortic aneurysm and liver cancer complicated by severe ischemic heart disease: report of a case.

We performed successful simultaneous operations for an abdominal aortic aneurysm (AAA) and liver cancer in a patient complicated by severe ischemic heart disease. A 59-year-old man with a history of liver dysfunction presented with acute epigastric pain. Abdominal computed tomography findings of ascites and a liver tumor indicated a diagnosis of ruptured hepatocellular carcinoma. He had a concomitant 65-mm AAA and a 48-mm right common iliac aneurysm. Elective surgery was scheduled because of his good general condition. Although triple-vessel disease was detected preoperatively, there were no graftable coronary arteries. The aneurysms were repaired first to utilize intra-aortic balloon pumping (IABP) during resection of the liver cancer, followed by left lateral segmentectomy. Perioperative hemodynamics were maintained by administering catecholamines and vasodilators, without the need for IABP. The patient was discharged on the 21st postoperative day without any complications, and no recurrence of liver cancer has been found in the 5 months since his operation.

Aortic Aneurysm, Abdominal↗
PubMed2003

Specific CTL activity of CD8+ TCR Vbeta14+ T cell in mouse 2, 4, 6-trinitrobenzene sulfonic acid-induced colitis.

We analyzed the functional role of CD8+ T-cell receptor (TCR) Vbeta14+ T cells, which increased specifically in the lamina propria in 2,4,6-trinitrobenzene sulfonic acid (TNBS) -induced colitis. Cytotoxic activity and cytokine production in CD8+ TCR Vbeta14+ T-cell clones were analyzed by 51Cr release assay and enzyme-linked immunosorbent assay, respectively. Cell transfer studies using these clones were performed. Established T-cell clones showed specific cytotoxic activity against TNBS-conjugated self spleen cells, and this cytotoxicity was completely inhibited by anti-TCR Vbeta14 monoclonal antibody. These clones produced interferon (IFN) - gamma in their culture supernatant, but neither interleukin (IL) - 2 nor IL-4. Histological findings of the colon in mice, which received clone transfer after enema with suboptimal doses of TNBS, showed massive colitis. Our results indicate that CD8+ TCR Vbeta14+ T cells had a cytotoxic T-lymphocyte function induced by Th-1 T-cell response and played a pathogenic role in the development of TNBS-induced colitis.

Adoptive Transfer↗
PubMed2003

Experimental studies on morphological changes of microcirculation of DMN-induced liver cirrhosis after normothermic ischemia with charge-coupled device microscope.

AIM: The purpose of the present experiment was to find indices for intraoperative ischemic-reperfusion injury in the cirrhotic liver. METHODS: One percent dimethylnitrosamine (DMN) was administered intraperitoneally to liver cirrhosis (LC) groups of Wister rats on three consecutive days of each week for a period of four weeks. The rats were divided into a N60 group with 60 minute ischemia in normal livers, a LC60 group with 60 minute ischemia in cirrhotic livers, and a LC30 group with 30 minute ischemia in cirrhotic livers. Digital videotapes recorded with a pencil lens-probe charge-coupled device (CCD) microscope were analyzed with NIH Image software. In zone 3, the sinusoid diameter (SD) was measured and the volume fraction (Vv) of zone 3 was calculated in preischemia and after 10, 20, 30, and 60 min of reperfusion. At the same time, bile flow was measured. RESULTS: The SD was significantly shorter in the cirrhotic liver groups than in the normal liver group at each point. The Vv after 60 min of reperfusion was significantly smaller in the LC60 group, with a survival rate of 0%, than in the LC30 group which had a survival rate of 67%. However, there was no significant difference in bile flow after 60 min of reperfusion in the LC30 and LC60 groups. Therefore, the Vv is suggested to be the better index for viability after ischemic-reperfusion. CONCLUSION: SD and Vv indicate microcirculatory differences and indices in the normal and cirrhotic livers in preischemia during reperfusion.

Animals↗
PubMed2002

Dielectric spectrogram for evaluating ischemic microstructural changes of the liver in simple cold preservation.

PURPOSE: Monitoring ischemic liver injury is important in liver transplantation. We previously reported that dielectric properties were correlated with tissue adenosine triphosphate during liver preservation; however, it is unknown what the changes in dielectric properties are based on. Using rats, we studied the relationship between dielectric parameters and microstructural changes in liver tissues during preservation. METHODS: We serially measured the percent decrease in conductivity and the percent increase in relative permittivity in rat livers, and determined the areas of cellular and extracellular components using a charge-coupled device microscope and an NIH image. Thereafter, we evaluated the relationship between dielectric parameters and microstructural changes in the liver tissues. RESULTS: A positive linear and exponential correlation was found between the percent decrease in conductivity and the percent decrease in extracellular components ( P < 0.01). A positive linear and exponential correlation was also found between the percent increase in relative permittivity and the percent increase in cellular components ( P < 0.01). CONCLUSIONS: Our results suggest that the serial changes in tissue conductivity and the relative permittivity reflect changes in liver tissue microstructures during cold preservation.

Animals↗