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Biomedical subjects

O Matsui

Publications and source records attributed to O Matsui.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Simulation model based on non-newtonian fluid mechanics applied to the evaluation of the embolic effect of emulsions of iodized oil and anticancer drug.

PURPOSE: To verify the difference in embolic effect between oil-in-water (O-W) and water-in-oil (W-O) emulsions composed of iodized oil and an anticancer drug, epirubicin, using a simulation model based on non-Newtonian fluid mechanics. METHODS: Flow curves of pure iodized oil and two types of O-W and W-O emulsions immediately and 1 hr after preparation were examined with a viscometer. Using the yield stress data obtained, we simulated the stagnation of each fluid with steady flow in a rigid tube. RESULTS: The W-O emulsions were observed to stagnate in the thin tube at a low pressure gradient. However, the embolic effect of the W-O emulsions decreased 1 hr after preparation. The O-W emulsions were stable and did not stagnate under the conditions in which the W-O emulsions stagnated. CONCLUSION: The simulation model showed that the embolic effect of the W-O emulsions was superior to that of the O-W emulsions.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

Partially covered Gianturco stent for tracheobronchial stricture caused by intraluminal tumor.

Partially covered Gianturco stents were used successfully in two patients to treat tracheobronchial strictures caused by intraluminal tumor growth. The stents were accurately placed without complications. The covered portion of the stent compressed the tumor, and prevented tumor ingrowth until the patients' deaths. This stent seems to act as effective palliation for tracheobronchial stricture caused by intraluminal tumor.

Aged↗
PubMedDate not supplied

Transjugular intrahepatic portosystemic shunt: histologic and immunohistochemical study of autopsy cases.

PURPOSE: To assess the histologic findings associated with stenosed and occluded transjugular intrahepatic portosystemic shunt (TIPS) tracts. METHODS: Four TIPS tracts within three autopsy livers were histologically studied for vascular components by routine staining and immunohistochemical staining. TIPS had been performed for bleeding from esophageal varices in patients with cirrhosis of the liver. RESULTS: Two TIPS, examined on days 4 and 53, showed occlusion by fibrin thrombus. In the former, no endothelial cells were detected, but coagulative necrosis of hepatocytes was found in the surrounding liver. In the latter, bile pigments were seen on the luminal surface. In the two other TIPS without tract occlusion, examined on days 49 and 293, a layer of endothelial cells, proliferation of smooth muscle cells, and deposition of an extracellular matrix such as collagen were confirmed. In the tract examined on day 293, there was protrusion of hepatocytes into the lumen through the stent wires. CONCLUSION: Short- and midterm TIPS occlusions were caused by thrombus forming after necrosis of hepatocytes and bile leakage, respectively. Long-term TIPS stenosis was associated with a combination of pseudointimal hyperplasia and ingrowth of hepatocytes.

Cell Division↗
PubMedDate not supplied

An experimental study of endovascular stenting with special reference to the effects on the aortic vasa vasorum.

PURPOSE: To evaluate the effects of bare stents and covered stents on the aortic wall, especially the vasa vasorum. METHODS: Eight bare stents and nine covered stents were placed in the infrarenal aorta of nine dogs. The dogs were euthanized at 4-45 weeks after stent placement. The vasa vasorum was evaluated by microstereoscopy with vascular casting, and the histopathology of the aortic wall was examined by light microscopy. RESULTS: In the unstented normal aorta, vasa vasorum nourished the adventitia and the outer media, and the intima and inner media were avascular. In the stented segment, vascular dilatation and proliferation of vasa vasorum, medial atrophy, and intimal hyperplasia were observed, more prominent for covered stents than for bare stents. CONCLUSION: Intravascular stent placement caused not only medial atrophy and intimal hyperplasia but also proliferation of the vasa vasorum, probably due to hypoxia in the aortic wall.

Animals↗
PubMedDate not supplied

Percutaneous transluminal angioplasty and stent placement for subclavian and brachiocephalic artery stenosis in aortitis syndrome.

A 43-year-old man with progressive right common carotid, subclavian artery, and brachiocephalic artery stenoses due to aortitis syndrome is presented. The patient's right common carotid artery had been treated by percutaneous transluminal angioplasty (PTA) four times previously, but it was finally occluded. The right subclavian artery was treated by PTA once, which resulted in restenosis. The stenosis extended to the brachiocephalic artery. For this patient, PTA followed by stent placement was performed for the right subclavian and brachiocephalic artery stenosis. Because arterial stenosis is progressive in cases of aortitis syndrome, simple PTA alone does not appear to be sufficient for treatment. We suggest that PTA followed by stent placement may be an alternative treatment for recurrent stenosis in aortitis syndrome.

Adult↗
PubMedDate not supplied

Malignant esophageal stricture and fistula: palliative treatment with polyurethane-covered Gianturco stent.

PURPOSE: To evaluate the effectiveness of a polyurethane-covered Gianturco stent in the palliative treatment of malignant esophageal stricture and fistula. PATIENTS AND METHODS: Twenty-seven patients with recurrent stricture (n = 24), fistula formation (n = 8), or both (n = 5) underwent palliative treatment for aphagia (n = 15) or dysphagia (n = 12). Eight patients had fistulas to the respiratory tract or mediastinum. A 15-F delivery sheath system was passed through the stricture; the inner dilator was removed, and the stent was compressed into the sheath and advanced with a pusher catheter. Follow-up included chest radiography for 3 days and monthly esophagography or endoscopy. RESULTS: Covered stents occluded fistulas and opened strictures in 100% of patients. Food intake was upgraded to liquids in 7% of patients, to soft foods in 37% and to regular foods in 56%. New stricture or fistula occurred in 4% and 7% of patients, respectively. Stent migration occurred in 15% of patients. Twenty-one patients died after stent placement, and average life expectancy was 11 weeks. CONCLUSION: A polyurethane-covered Gianturco stent is effective in the palliation of advanced malignant esophageal strictures and fistulas.

Aged↗
PubMedDate not supplied

Covered gianturco stents for malignant biliary obstruction: preliminary clinical evaluation.

PURPOSE: To evaluate the effectiveness of covered Gianturco stents in patients with malignant biliary obstruction. MATERIALS AND METHODS: Three types of partially polyurethane-covered stents were implanted in 19 patients with malignant biliary obstruction located distal to the hilar confluence. A transhepatic approach was employed in all but one patient, in whom the stent was placed through a T-tube tract. RESULTS: Stent placement was possible in all patients. In 15 patients, the implanted stents were expanded to a mean of 81% of their original diameter. In the remaining four patients, the stents expanded to less than 40% of the original diameter, and balloon dilation and additional bare stent placement were required. All patients except one, who had impairment of liver function due to multiple liver metastases, showed relief of jaundice after stent placement. At follow-up, which ranged from 5 to 57 weeks (mean, 24.7 weeks), one stent (5%) was occluded after 26 weeks due to tumor growth above the upper stent edge, and required secondary intervention. Complications in three patients included stent migration in one (5%) and cholangitis in two (11%). CONCLUSION: Preliminary results suggest that placement of covered Gianturco stents is feasible, the complication rate is acceptable, and short-term patency appears promising.

Adult↗
PubMedDate not supplied

Subsegmental transcatheter arterial embolization for hepatocellular carcinoma in the caudate lobe.

PURPOSE: To clarify the effectiveness of transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC) in the caudate lobe of the liver. MATERIALS AND METHODS: Thirteen patients with HCC in the caudate lobe underwent TAE. TAE was performed by injection of the mixture of anticancer drugs (mitomycin C and doxorubicin or epirubicin) and iodized oil, followed by gelatin sponge particles. Arterial anatomy of the caudate branch, local recurrence rate, and survival rate were evaluated. RESULTS: From 31 TAEs for the caudate lobe, 22 subsegmental TAEs were successfully performed (71%). Local recurrence in the caudate lobe was seen in 10 patients (77%). Subsegmental TAE for the caudate lobe was repeated one to five times. Cumulative local recurrence rates were 33% and 75% within 3 and 6 months, respectively. Survival rates after first TAE for HCC in the caudate lobe were 89% and 74% for 1 and 3 years, respectively. CONCLUSION: Local recurrence rate after subsegmental TAE for HCC in the caudate lobe was high. However, repeated subsegmental TAE possibly improves the prognosis of HCC in the caudate lobe.

Aged↗
PubMedDate not supplied

Dynamic computed tomography during arterial portography: the most sensitive examination for small hepatocellular carcinomas.

The efficacy of dynamic sequential CT with table incrementation during arterial portography (DSCTI-AP) in the detection of small hepatocellular carcinomas (HCC) (less than 3 cm in diameter and less than three in number) was analyzed in comparison with other imaging methods including radionuclide (RN) liver scans, ultrasound (US), CT, selective celiac angiography (SCA), and infusion hepatic angiography (IHA). The sensitivity of each study in detecting 19 cases of small HCC was as follows: RN, 16%; US, 63%; CT, 58%; SCA, 58%; IHA, 83%; and DSCTI-AP, 95%. Three of 19 cases were diagnosed only by DSCTI-AP and one case that could not be visualized by DSCTI-AP was opacified by IHA. Dynamic sequential CT with table incrementation during arterial portography was superior to IHA in visualizing small HCCs.

Adult↗
PubMedDate not supplied

Calcification in caval membrane causing primary Budd-Chiari syndrome: CT demonstration.

We report two cases of membranous obstruction of the inferior vena cava (MOIVC) in which we observed patchy calcification in the membrane. The location of the calcification in the membrane was confirmed histologically. This finding was found histologically in four of eight cases of MOIVC, and it is a useful finding in the CT diagnosis of MOIVC.

Aged↗
PubMedDate not supplied

Transient subpleural curvilinear shadow caused by pulmonary congestion.

We present two cases of transient subpleural curvilinear shadows (SCSs) on CT caused by pulmonary congestion. Subpleural curvilinear shadows, which are usually visible in the middle or lower dorsal lung field on CT, have been reported as the initial finding of pulmonary fibrosis. But SCS is not a specific finding since pulmonary congestion may be one cause of it.

Aged↗
PubMedDate not supplied

MR imaging in idiopathic portal hypertension.

Magnetic resonance imaging was performed in four patients with biopsy proven idiopathic portal hypertension (IPH). The MR images show proximity of medium-sized intrahepatic vessels to each other and to the liver surface in all patients. Small vessels running parallel to the second order branches of the intrahepatic portal vein are commonly seen as collateral pathways of portal flow in IPH and were seen in two patients. These findings were clearly demonstrated on gradient-recalled echo images. Intrahepatic periportal abnormal high intensity was seen in all patients on T2-weighted images and may reflect abnormalities in the portal tracts such as fibrous enlargement and increase in the number of vascular channels. Tiny low-intensity nodules sometimes observed in liver cirrhosis were not seen in any patient. Magnetic resonance was a useful noninvasive method in the differentiation of IPH from liver cirrhosis.

Aged↗
PubMedDate not supplied

Segmental hepatic iron deposition due to peripheral portal vein tumor thrombus: MR features.

We report a case of segmental hepatic iron deposition in the parenchyma peripheral to a tumor-thrombosed intrahepatic portal vein. On MR imaging, especially fast low-angle shot image, the liver parenchyma was demonstrated as a hypointense area with segmental and wedge-shaped configuration. Absence of portal blood flow may cause such segmental hepatic iron deposition.

Aged↗
PubMedDate not supplied

Delayed enhancement of fibrotic areas in hepatic masses: CT-pathologic correlation.

We report a histological analysis of the areas of high density in the postequilibrium and delayed phase CT in 43 focal hepatic lesions. The cases consisted of 16 cholangiocellular carcinomas, 9 hepatocellular carcinomas (including a sclerosing type of hepatocellular carcinoma and a combined hepatocellular-cholangiocellular carcinoma), 13 metastases, 2 granulomas, an inflammatory pseudotumor, a malignant lymphoma, and an epithelioid hemangioendothelioma. Computed tomography was performed after hepatic angiography using 40-50 g iodine and arteriographic CT using 35 g iodine. The areas of delayed enhancement corresponded histologically to fibrotic tissues, from inflammatory change to extensive fibrosis.

Adenoma, Bile Duct↗
PubMedDate not supplied

Enhancement of ascites on MRI following intravenous administration of Gd-DTPA.

OBJECTIVE: The enhancement of ascites following intravenous administration of Gd-DTPA on MRI was investigated. MATERIALS AND METHODS: Magnetic resonance imaging was performed in 20 patients with ascites (8 peritoneal carcinomatosis, 2 tuberculous peritonitis, 8 liver cirrhosis, 1 nephrotic syndrome, 1 peritoneal adhesion), and T1-weighted SE images were obtained before and 15-20 min following intravenous administration of Gd-DTPA (0.1 mmol/kg). RESULTS: There were 10 exudative ascites and 10 transudative ascites. Eight of 10 exudative ascites showed enhancement, in contrast to none of 10 transudative ascites. The precontrast signal intensity ratios (SIRs) of exudative ascites were significantly higher (p < 0.05) than those of transudative ascites, and the postcontrast SIRs of exudative ascites were significantly higher (p < 0.01) than those of transudative ascites. This difference was thought to be caused by increased peritoneal permeability and higher protein concentration in the cases with exudative ascites in this study. CONCLUSION: It is concluded that enhancement of ascites on MRI obtained 15-20 min after intravenous administration of Gd-DTPA is not an uncommon finding in exudative ascites (especially associated with peritoneal carcinomatosis).

Ascites↗