PubMed Health⌕ Search

Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 1,747 records · Page 97Linked to original sources
PubMedDate not supplied

MRA in the evaluation of EC-IC bypass patency.

OBJECTIVE: Our goal was to determine the value and limitations of three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) for evaluating the patency of extracranial (EC)-intracranial (IC) bypasses. MATERIALS AND METHODS: The 3D TOF MRA was performed in 35 patients to evaluate their EC-IC bypasses (50 sites) at 1.5 T. Subtraction (rephased-dephased) MRA was performed to visualize slowly flowing blood in all patients. Angiographic images were obtained using maximum intensity projection from subtraction images and from rephased images. RESULTS: The patency of bypasses was confirmed at 22 sites and was suggestive at 17 other sites using MRA alone. The diagnostic value of subtraction MRA proved to be superior to that of rephased MRA, and the findings of subtraction MRA correlated relatively well with those of conventional angiography. Edited reprojection MR angiograms were helpful in visualizing collateral vessels without overlapping of vessels. CONCLUSION: Although there have been some problems with MRA so far, it is a useful imaging modality for following up patients who have undergone EC-IC bypass operations, in conjunction with clinical examination, transcranial Doppler sonography, and cerebral blood flow studies using single photon emission CT or PET.

Adolescent↗
PubMedDate not supplied

Malignant hemangiopericytoma of the breast.

A55-year-old woman presented with 1-year history of mass in the right breast. Incisional biopsy showed the tumor to be malignant hemangiopericytoma from its histology. The tumor showed low--intermediate density and peripheral contrast enhancement on CT, and inhomogeneous mixed-signal intensity both on T1W and T2W images, and peripheral enhancement with Gd-DTPA on MRI with no invasion of the duct.

Biopsy↗
PubMedDate not supplied

Gastrointestinal stromal tumor arising in the rectovaginal septum.

We report herein a rare case of malignant gastrointestinal stromal tumor (GIST) originated from the rectal wall, which presented as a tumor on the rectovaginal septum. A 54-year-old Japanese woman, gravida 4, para 3, was admitted complaining of anuresis and severe constipation. She had a history of hysterectomy and right salpingo-oophorectomy for uterine leiomyoma 11 years previously. Pelvic examination revealed an 8.5 x 7.5 x 7.5 cm hard mass in the rectovaginal space. The inferior border of the tumor was 2 cm from the vaginal introitus and 2 cm from the anus. Computed tomography and magnetic resonance imaging showed a well-circumscribed soft-tissue mass filling the rectovaginal space. Urinary bladder and rectum were markedly compressed and displaced. Colon fiberscopy revealed invasion of the tumor into the rectal mucosa. An abdominoperineal resection of the rectum with posterior vaginal wall resection and pelvic lymphadenectomy was performed. The resected specimen showed a rectal submucosal tumor that was 8 x 8 x 7 cm in size. The tumor was diagnosed as a malignant GIST. Immunohistochemical analysis confirmed this diagnosis. The patient is now healthy without evidence of recurrence at 13 months after surgery. Gynecologists should be aware of rectal GIST arising in the rectovaginal space as a differential diagnosis of vaginal submucosal tumor.

Diagnosis, Differential↗
PubMedDate not supplied

Portal circulation in monkeys and humans studied after ingestion of a capsule containing a radionuclide.

Capsules (8 x 30 mm) of technetium-99m pertechnetate were designed for measurement of portal blood flow. Most of the radionuclide entered the superior mesenteric vein. The capsule was taken orally and monitored with a collimator for scintigraphy until it reached the small intestine, when a magnetic field completed an electrical circuit in a sensor, burning a thread, releasing a spring, and discharging the preparation. A study in crab-eating monkeys (Macaca fascicularis) showed that the radionuclide in the small intestine circulated through the superior mesenteric vein to the portal vein and liver. Portal scintigraphy through the small intestine could be analysed in the same way as per-rectal portal scintigraphy, in which blood flow mostly from the inferior mesenteric vein is evaluated. A study of four volunteers showed that, after the radionuclide was released, it circulated through the superior mesenteric vein to the portal vein and liver. Use of a capsule enclosing a radioisotope was possible, and the procedure seemed to be safe. The use of the per-small intestine method plus the per-rectal method should give more accurate results than either method used alone, because the haemodynamics of both the superior and inferior mesenteric vein would be reflected.

Administration, Oral↗
PubMedDate not supplied

Significance of blood flow in the inferior and superior mesenteric veins for the formation of oesophageal varices.

The degree of involvement of blood flow in the superior mesenteric vein and inferior mesenteric vein in the formation of oesophageal varices is not known. We have developed a method by which the contributions of these veins to portal blood flow can be evaluated simultaneously in a relatively non-invasive way. An enteric-coated capsule containing [123I]iodoamphetamine (IMP) is given by mouth and 3 h later [123I]IMP is instilled into the rectum. The data obtained are treated by computer to calculate the portal shunt index via the inferior and superior mesenteric veins. In chronic hepatitis and cirrhosis, when varices were absent, the difference in these indices was not significant. In the presence of varices, the portal shunt index via the inferior mesenteric vein was significantly higher than that via the superior mesenteric vein. It was suggested that the contribution of blood flow in the inferior mesenteric vein the portal/splenic axis is important in the formation of varices.

Amphetamines↗
PubMedDate not supplied

Effect of drinking on the outcome of cirrhosis in patients with hepatitis B or C.

Survival rates were calculated for 251 patients with cirrhosis of the liver but without hepatocellular carcinoma, primary biliary cirrhosis, or autoimmune cirrhosis who underwent laparoscopy during the past 21 years at the authors' hospital. The survival rates were calculated by the Kaplan-Meier method. Stored serum was assayed for hepatitis B surface antigen (HBsAg) and antibodies to the hepatitis C virus (HCV). Patients with alcoholic cirrhosis had significantly better survival rates than patients with HBsAg, HCV, or both. Differences in survival rates between patients with hepatitis B and C were insignificant. In both groups, habitual drinkers had a significantly lower survival rate. The results suggested that alcohol accelerates liver damage in subjects with viral hepatitis.

Adult↗
PubMedDate not supplied

Relationship between endotoxin antibody levels and portal systemic shunt evaluated by per-rectal portal scintigraphy.

The reasons for the high frequency of endotoxaemia in cirrhosis, whether poor liver function or abnormal portal circulation, are not known. Accurate measurement of endotoxin itself is difficult. Instead, in this study an enzyme-linked immunosorbent assay was used to measure levels of IgA, IgG and IgM antibodies to endotoxin in patients with chronic liver disease and underlying hepatic viral infection. The relationships between the results and clinical symptoms or the presence of a portal systemic shunt were investigated. The median level of IgA antibodies was not different in patients with chronic hepatitis and those with cirrhosis, and the same was found for IgM, but the median level of IgG antibodies was significantly higher in the patients with cirrhosis. When patients with cirrhosis were grouped by the presence or absence of ascites or hepatocellular carcinoma, no significant difference was observed in any of these antibody levels. However, in cirrhotic patients with varices, the level of IgG antibodies to endotoxin was significantly higher than in patients without varices. For evaluation of the portal systemic shunt, the per-rectal portal shunt index was calculated. There was a significant correlation (R = 0.431, P < 0.001) between the per-rectal portal shunt index and the level of IgG antibodies to endotoxin. That is, the degree of abnormality in the portal haemodynamics was correlated with the level of IgG antibodies to endotoxin in patients with liver disease.

Antibodies, Bacterial↗
PubMedDate not supplied

Mutational state of von Hippel-Lindau and adenomatous polyposis coli genes in renal tumors.

Genetic alterations of the von Hippel-Lindau (VHL) tumor suppressor gene and the adenomatous polyposis coli (APC) gene in renal tumors were examined by PCR-SSCP analysis and direct sequencing. Tissues from 58 primary sporadic human renal cell tumors (49 clear-cell carcinomas, 6 non-clear-cell carcinomas and 3 oncocytomas) from Japanese patients were used in this study. Somatic VHL mutations were detected in 26 (53%) of the clear-cell carcinomas, although no mutations in this gene were observed in any non-clear-cell carcinomas or oncocytomas. The frequency of mutations did not correlate with histological grade, clinical stage or any of several other clinical factors examined. No differences in the frequency of VHL mutations or in the exons where mutations occurred within the gene were evident when we compared our results with those reported for American patients. However, frameshifts were more common in our Japanese panel of tumors than in American cases, where single-point mutations appear to be more frequent. No APC gene mutation was detected in any of our samples. These results indicate that VHL gene mutations are related to the carcinogenesis of the clear-cell type of primary renal cell carcinomas, whereas alteration of the APC gene is not involved in the pathogenesis of this cancer.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Effect of methionine-deprived nutrition on cell growth and cell kinetics in cell cultures and experimental tumors.

The effect of methionine-deprived nutrition on cell growth and cell kinetics was investigated in cell cultures and in tumor-bearing rats using the total parenteral nutrition (TPN) technique. A simultaneous flow cytometric measurement of the cellular DNA content and the amount of 5-bromodeoxyuridine incorporated into cellular DNA was performed for analysis of cell kinetics. The methionine-free medium demonstrated a cytocidal effect on the growth of SLC cells after 6 hours of culturing. It decreased viability from 80% in the control medium to 23%, and it decreased the S phase and increased the G0/G1 phase of the cell cycles. The methionine-deprived medium showed a concentration-dependent inhibition in cellular growth. Methionine-deprived TPN was seen to inhibit AH109A and SLC tumor growth compared with conventional TPN and decreased the S phase and increased the G0/G1 phase of cell cycles. These results confirm that methionine deprivation blocks cells from processing into the G1 phase and recycling, and that it is effective in inhibiting tumor growth in cultures and in vivo.

Animals↗
PubMedDate not supplied

A novel Philadelphia chromosome-positive cell line with multipotential properties.

A novel Philadelphia chromosome-positive cell line was established from the peripheral blood of a patient with chronic myelogenous leukemia in megakaryoblastic crisis. This cell line, designated TN922 showed the positive phenotypes for myeloid, monocyte-macrophage, erythroid and megakaryocytic markers. The stimulation with phorbol 12-myristate 13-acetate (PMA) increased the expression of megakaryocytic markers including the platelet peroxidase activity, dimethylsulfoxide or transforming growth factor-beta promoted up-regulation of the erythroid markers. Stimulation with PMA, tumor necrosis factor-alpha or interleukin-6 also brought about the expression of monocytoid markers. These findings indicated that TN922 cell line has the property of acting as multipotential progenitor cells. TN922 cells showed gradual growth in the absence of growth factors but the addition of granulocyte/macrophage colony-stimulating factor (GM-CSF) promoted cell growth. The message of GM-CSF was detected in TN922 cells and the neutralizing antibody against GM-CSF receptor alpha-subunit suppressed cell growth. These results indicated that TN922 cell line proliferates in an autocrine secretion of GM-CSF.

Aged↗
PubMedDate not supplied

Decreased hepatic nitric oxide synthesis during liver surgery.

BACKGROUND/AIMS: Liver cells can produce nitric oxide from L-arginine through the action of nitric oxide synthase, but local changes in the concentrations of nitric oxide-related metabolites during liver surgery are not well characterized. We investigated such changes during and after liver surgery. METHODOLOGY: We determined nitrite plus nitrate, L-arginine and L-citrulline concentrations in radial arterial and hepatic venous blood during and after liver surgery in 17 patients. Portal venous blood concentrations were also measured at the end of surgery in 7 patients. RESULTS: Both arterial and hepatic venous nitrite plus nitrate concentrations were significantly decreased during surgery and remained low compared to pre-operative values until post-operative day 2. Arterial and hepatic venous nitrite plus nitrate concentrations were not significantly different. L-arginine concentrations in both arterial and hepatic venous blood were significantly decreased during surgery, but returned to pre-operative levels on post-operative day 1. L-arginine concentrations in hepatic venous blood were significantly lower than in arterial blood. L-citrulline concentrations in both arterial and hepatic venous blood were significantly decreased during surgery compared to pre-operative values, and tend to be decreased until post-operative day 2. L-citrulline concentrations were significantly higher in hepatic venous blood than in arterial blood. CONCLUSIONS: Hepatic nitric oxide production was decreased peri-operatively during liver surgery. The decreases in L-arginine concentrations and in nitric oxide synthase activity may account for the decrease in nitric oxide production.

Adult↗
PubMedDate not supplied

Outcome of acute ischemic lesions evaluated by diffusion and perfusion MR imaging.

BACKGROUND AND PURPOSE: Diffusion and perfusion MR imaging have been reported to be valuable in the diagnosis of acute ischemia. Our purpose was to ascertain the value of these techniques in the prediction of ischemic injury and estimation of infarction size, as determined on follow-up examinations. METHODS: We studied 18 patients with acute ischemic stroke who underwent echo-planar perfusion and diffusion imaging within 72 hours of symptom onset. Quantitative volume measurements of ischemic lesions were derived from relative mean transit time (rMTT) maps, relative cerebral blood volume (rCBV) maps, and/or apparent diffusion coefficient (ADC) maps. Follow-up examinations were performed to verify clinical suspicion of infarction and to calculate the true infarction size. RESULTS: Twenty-five ischemic lesions were detected during the acute phase, and 14 of these were confirmed as infarcts on follow-up images. Both ADC and rMTT maps had a higher sensitivity (86%) than the rCBV map (79%), and the rCBV map had the highest specificity (91%) for detection of infarction as judged on follow-up images. The rMTT and ADC maps tended to overestimate infarction size (by 282% and 182%, respectively), whereas the rCBV map appeared to be more precise (117%). Significant differences were found between ADC and rMTT maps, and between rCBV and rMTT maps. CONCLUSION: Our data indicate that all three techniques are sensitive in detecting early ischemic injury within 72 hours of symptom onset but tend to overestimate the true infarction size. The best methods for detecting ischemic injury and for estimating infarction size appear to be the ADC map and the rCBV map, respectively, and the diffusion abnormality may indicate early changes of both reversible and irreversible ischemia.

Acute Disease↗
PubMedDate not supplied

Multidrug resistance due to impaired DNA cleavage in a VP-16-resistant human leukemia cell line.

We established a VP-16-resistant line of human leukemia cells, K562/VP-H2, derived from K562 cells. K562/VP-H2 cells were 44-fold more resistant to VP-16 than were K562 cells. K562/VP-H2 cells were also resistant to doxorubicin, daunorubicin and mitoxantrone, but showed little or no resistance to vincristine, aclarubicin, idarubicin, idarubicinol, cytosine arabinoside, cis-platinum or camptothecin. K562/VP-H2 cells did not over-express P-glycoprotein or multidrug resistance protein, and showed intracellular accumulation of VP-16 similar to that in K562 cells. While the expressions of topoisomerase II-alpha gene and topoisomerase II-beta gene, or catalytic activity in nuclear extract of K562/VP-H2 cells were similar to that of K562 cells, the VP-16 induced DNA cleavage was reduced in K562/VP-H2 cells compared to K562 cells, suggesting that the reduction of topoisomerase II-mediated DNA cleavage through qualitative alteration of topoisomerase II may be the main mechanism of acquired multidrug resistance for K562/VP-H2 cells. The K562/VP-H2 cell line is an interesting model for studying resistance to antileukemia drugs targeting topoisomerase II.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

Molecular remission induced by fractionated dose-escalating donor leukocyte infusion without graft-versus-host disease in a patient with chronic myelogenous leukemia relapsed after allogeneic bone marrow transplantation.

A 39-year-old male with CML who relapsed 5 years and 8 months after allogeneic bone marrow transplantation achieved complete molecular remission following fractionated dose-escalating donor leukocyte infusions. Acute or chronic graft-versus-host disease (GVHD) did not occur and the patient remained asymptomatic throughout treatment. Since no prophylaxis against GVHD was administered, this case indicated that the graft-versus-leukemia effect is entirely separate from GVHD in certain conditions.

Adult↗