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T Kumazaki

Publications and source records attributed to T Kumazaki.

At least 19 recordsLinked to original sources
PubMed1998

Enhanced expression of mitochondrial genes in senescent endothelial cells and fibroblasts.

It has been suggested that some mitochondrial genes are important in cellular senescence. In order to identify the mitochondrial genes that are involved in cellular senescence, we have constructed a cDNA library from senescent human vascular endothelial cells and isolated 86 senescence-specific cDNA clones by differential screening. Among the clones, we identified four distinct mitochondrial genes including NADH dehydrogenase subunit 2 (ND2), ND3, ATPase 6 and 16S ribosomal RNA. We then compared the levels of expression of these genes in young and senescent cells by using two endothelial and two fibroblast cell strains. Northern blot and slot blot hybridization confirmed that the expression levels of ND3, ATPase 6 and 16S rRNA were elevated in senescent cells of all four strains. The expression level of ND2 was also elevated during cellular senescence in three of the four strains. Because mitochondria are actively involved in oxidative phosphorylation and respiratory functions, the altered expression levels of these genes may participate in aging processes.

Adenosine Triphosphatases↗
PubMed1998

Acute traumatic injury of the distal descending aorta associated with thoracic spine injury.

A rare case of traumatic injury of the distal descending aorta associated with thoracic spine injury is reported. A 21-year-old man was admitted after a traffic accident. Thoracic CT and angiography demonstrated a false aneurysm of the distal descending aorta and a compression fracture of the eleventh thoracic vertebra. At emergency surgery, a transverse linear tear at the level of the aortic hiatus was confirmed and repaired.

Accidents, Traffic↗
PubMed1998

Mesenteric schwannoma.

Schwannoma is a benign neurogenic tumor arising from the sheath of peripheral nerves. It occurs very rarely in the mesentery, where it is difficult to diagnose. Herein we describe a case in which contrast-enhanced CT and gadolinium-DTPA-enhanced MR showed a locally enhanced well-defined tumor with a cystic component just anterior to the duodenum. These findings corresponded well to the resected specimen.

Contrast Media↗
PubMed1998

[Transjugular intrahepatic portosystemic shunt for the treatment of refractory ascites].

Five cirrhotic patients with refractory ascites were treated with transjugular intrahepatic portosystemic shunt (TIPS). Before TIPS, although patients were received salt restriction (5 g/day), diuretic therapy (furosemide 112 mg/day, spironolactone 140 mg/day), albumin infusion and paracentesis, ascites did not show improvement. After TIPS, urine volume and urinary sodium excretion increased significantly. Mean body weight decreased significantly from 73 kg before TIPS to 63 kg a month after TIPS. Improvement of ascites after TIPS were associated with a significant reduction in the dose of diuretics. On discharge, complete resolution of ascites was found in 2 patients and mild ascites remained in 3 other patients. Four patients presented 6 episodes of shunt stenosis in the follow-up period, and were treated with balloon dilatation. Ascites increased on shunt dysfunction and showed improvement after balloon dilatation. Post-TIPS encephalopathy was seen in 2 patients and one of 2 was disabled. In conclusion, although post-TIPS shunt dysfunction and encephalopathy are common. TIPS is an effective therapy for refractory ascites in patients with cirrhosis.

Ascites↗
PubMed1997

Molecular targeting of mitomycin C chemotherapy.

In 10 human cancer cell lines, the activity of mitomycin C (MMC) was found to be determined by an interplay between activation by DT-diaphorase (DTD) and inactivation by glutathione S-transferase (GST). NADPH/cytochrome P-450 reductase was not responsible for MMC activation and expression of MDRI (Mr 170,000 P-glycoprotein), and MRP (multidrug resistance-associated protein) genes did not relate to MMC resistance. Gene expression analysis for NQO1 (DTD gene) and GSTpi predicted which enzyme activity predominated in a cell line, except K562 and K562/DOX. For tumors with DTD activity only, MMC given by itself was most active. In cell lines in which DTD action was predominant, tumor selectivity was achieved by enhancing DTD-mediated activation with m-iodobenzylguanidine and hyperglycemia, which reduced the intra-tumoral pH. KW2149, a novel MMC analogue activated by glutathione, was most active against tumors in which GSTpi predominated. These various enzyme-specific effects could be observed even in cell lines derived from tumors with multidrug resistance. Such MMC treatment based on cell enzymology may enhance significantly MMC efficacy, helping to overcome multidrug resistance.

Animals↗
PubMed1997

Arteriovenous malformation of the gallbladder.

Review of the literature shows no reports of vascular malformation of the gallbladder. Herein we report an unusual case of arteriovenous malformation of the gallbladder in a patient with hepatocellular carcinoma. The gallbladder lesion was found incidentally during abdominal angiography for the carcinoma. The angiographic features were specific, comprising dilated and tortuous feeding cystic arteries, a racemose vascular network, and early-filling cystic veins.

Adult↗
PubMed1997

Magnetization transfer imaging of bone marrow with and without fat suppression.

RATIONALE AND OBJECTIVES: To assess magnetization transfer (MT) ratios of bone marrow at magnetic resonance (MR) imaging performed with and without fat suppression. MATERIALS AND METHODS: The authors performed MR imaging in 30 regions of normal bone marrow in 10 subjects by using four types of gradient-echo sequences: a combination of MT and fat-suppression techniques, only the fat-suppression technique, only the MT technique, and without MT or fat-suppression techniques. MT ratios of marrow obtained with and without the fat-suppression technique were quantitatively compared. RESULTS: The average MT ratio of marrow with fat suppression was significantly higher than that without fat suppression (P < .01). CONCLUSION: Because bone marrow includes both water and fat, the MT ratio of marrow was underestimated when MT imaging was performed without fat suppression. A fat-suppression technique should be used.

Adipose Tissue↗
PubMed1997

K-space filter effect in three-dimensional contrast MR angiography.

PURPOSE: In three-dimensional (3-D) contrast MR angiography, temporal misregistration between the data acquisition period and the arrival of the contrast agent in the target vessels is thought to degrade the quality of the reconstructed images. The purpose of this study was to demonstrate and investigate this effect in phantom experiments. MATERIAL AND METHODS: MR images of a phantom tube were evaluated with flowing materials of water or Gd-DTPA solution by changing from water to Gd-DTPA solution halfway through the data acquisition period. RESULTS: While no signal could be acquired with a stream of water in the tube, a clear signal was obtained with a flow of Gd-DTPA solution. Blurring and ghost artifacts surrounding the tube along the phase-encoding direction were observed when the flowing material was changed from water to Gd-DTPA solution halfway through the data acquisition period. CONCLUSION: K-space filter effect occurs during 3-D contrast MR angiography owing to the transient passage of the contrast agent, and this effect causes spatial artifacts in the reconstructed images.

Artifacts↗
PubMed1997

The value of emergency CT studies in spontaneous rupture of hepatocellular carcinoma. Analysis for tumor protrusion and hemorrhagic ascites.

CT characteristics of spontaneous rupture of HCC (n = 13) were reviewed retrospectively, and the value of emergency CT studies in this disease was evaluated. Especially, tumor protrusion ratio (TPR) and ascitic CT numbers were measured to for comparison with the data for unruptured HCCs and ordinary (e.g. non hemorrhagic) ascites (n = 13). As a result, except for diffuse type HCCs, the TPR was significantly higher than for the unruptured HCCs. Nine cases had intraperitoneal HDAs, and the laterality of the HDAs corresponded with that of the ruptured tumors in 8 cases. Also, the ascitic CT numbers apart from the HDA were still higher than the ordinary ascites. Therefore, a high TPR, HDAs adjacent to the tumor, and elevated ascitic CT numbers are important CT manifestations indicating HCC rupture. Diffuse HCCs, however, require careful clinical evaluation.

Adult↗
PubMed1997

Normal contrast enhancement of extraocular muscles: fat-suppressed MR findings.

PURPOSE: To evaluate contrast enhancement of normal extraocular muscles in the orbit. METHODS: Noncontrast and contrast-enhanced T1-weighted images of the orbit were acquired using a fat-suppression MR technique in eight patients with no orbital disease. Contrast enhancement of 64 extraocular muscles was evaluated and compared with that of 16 temporal muscles. RESULTS: Compared with temporal muscles, all extraocular muscles markedly enhanced after administration of contrast material. CONCLUSIONS: Because normal extraocular muscles enhanced markedly with contrast material, more attention should be paid to these muscles when using contrast-enhanced, fat-suppressed T1-weighted MR imaging to evaluate pathologic conditions.

Adipose Tissue↗
PubMed1997

[Uterine cervical carcinoma after radiotherapy: comparison between MR imaging and histopathological findings].

The findings of MRI and pathologic investigation were correlated in curatively irradiated uterine cervical carcinoma. Four patients having residual carcinoma diagnosed by biopsy underwent hysterectomy. MRI demonstrated the mass lesion in one patient with pathologic confirmation of massive viable cancer cells (case I). Of the other three patients, MRI demonstrated normal configuration of the uterine cervix. Cervical signal intensity, however, varied. Hyperintensity was noted in an area of the posterior wall on T2WI in case 2. The anterior wall of the case 2 and the other two cases showed hypointensity. Cervical specimens with normal intensity showed only a small number of degenerated cancer cells. On the other hand, pathologic examination of the posterior wall of the case 2 revealed both cancer cells with varying degrees of degeneration and necrotic tissues. Degeneration of cancer cells was stronger in the superficial layer than the deeper layer. Fibrosis, hemorrhage, granulation and hyalinization were hypointense on T2WI. T2 elongation reflected not only the residual tumor but the post-irradiation changes. Post-irradiated cervix with normal intensity indicated that only a small number of degenerated cancer cells may persist even if the biopsy was positive. We conclude that MRI is useful in evaluating tumor response to radiotherapy.

Carcinoma, Mucoepidermoid↗
PubMed1997

[Evaluation of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral vasospasm].

We evaluated the usefulness of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral vasospasm following subarachnoid hemorrhage (SAH). Eleven patients with SAH who were suspected of having cerebral vasospasm on the basis of their clinical symptoms were examined by 3D-CTA with a spiral CT scanner after an intravenous bolus administration of contrast medium. 3D-CTA revealed vasospastic changes of the cerebral vessels in eight patients. Conventional angiography was performed in six patients immediately after the 3D-CTA examination, and demonstrated the cerebral vasospasm. In eight patients, a second 3D-CTA was performed with the same technique one week after the first 3D-CTA examination. The second 3D-CTA showed the cerebral vessels without vasospastic change. In conclusion, 3D-CTA is a promising, minimally invasive strategy for the assessment of cerebral vasospasm.

Cerebral Angiography↗
PubMed1997

[Diagnostic imaging of "body packers"].

Drug smuggling by intra-abdominal concealment, so called "body packing," has recently increased, even in Japan. Because of fatal drug intoxication and other adverse side effects, it is important to make a radiological diagnosis of body packers as soon as possible. A retrospective analysis of the images of plain abdominal radiography, computed tomography (CT) and ultrasound (US) was performed in twenty-three body packers to evaluate the imaging characteristics of three drugs (cannabis, cocaine and heroin). Cannabis (16 patients) and cocaine (5 patients) packages were demonstrated as well-demarcated rectangular-shaped high-density shadows surrounded by gas halo ("double condom sign") in abdominal plain radiographs and CT. Heroin packages (2 patients) were demonstrated as obscure shadows and were difficult to identify on plain radiographs, because they resembled stool masses. US was performed in one cannabis patient because of the refusal of radiological examination, and packages were demonstrated as round echogenic structures with dorsal echo extinctions. In conclusion, abdominal plain radiography, CT and US represent valuable diagnostic modalities in the assessment of body packers.

Abdomen↗
PubMed1997

[The usefulness and the problems of attenuation correction using simultaneous transmission and emission data acquisition method: studies on normal volunteers and phantom].

Attenuation correction using simultaneous transmission data (TCT) and emission data (ECT) acquisition method was applied to 201Tl myocardial SPECT with ten normal adults and the phantom in order to validate the efficacy of attenuation correction using this method. Normal adults study demonstrated improved 201Tl accumulation to the septal wall and the posterior wall of the left ventricle and relative decreased activities in the lateral wall with attenuation correction (p < 0.05: paired t-test). The counts of the posterior wall were however, significantly higher than those of the anterior wall and the lateral wall (p < 0.05: unpaired t-test). Moreover, relative low uptake of the apex was enhanced using attenuation correction. Static phantom studies revealed the self scatter from high 201Tl uptake organs such as the liver and the stomach pushed up the activities in the septal wall and the posterior wall. Cardiac dynamic phantom studies showed partial volume effect due to cardiac motion contributed to under-correction of the apex, which might be overcome using gated SPECT. Although simultaneous TCT and ECT acquisition was conceived of the advantageous method for attenuation correction, miss-correction of the special myocardial segments should be taken into account in assessment of attenuation correction compensated images.

Adult↗