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T Okuda

Publications and source records attributed to T Okuda.

628 records · Page 35Linked to original sources
PubMedDate not supplied

Contrast-enhanced CISS MRI of vestibular schwannomas: phantom and clinical studies.

PURPOSE: The purpose of this work was to assess the changes of signal intensity on constructive interference in steady state (CISS) 3D Fourier transformation (3DFT) MRI after administration of Gd-DTPA and to evaluate the efficacy of contrast-enhanced CISS-3DFT MRI to depict the seventh and eighth cranial nerves affected by vestibular schwannomas. METHOD: All scans were carried out on a 1.5 T MR unit. First, an experimental study was conducted to evaluate the changes in signal intensity of the CISS-3DFT sequence in relation to the concentration of contrast medium. Second, nine consecutive patients with 11 vestibular schwannomas underwent CISS-3DFT imaging before and after contrast agent administration. Signal intensities of the tumors and nerves were measured and compared between the pre- and postcontrast images. Visualization of the facial and cochlear nerves was rated on pre- and postcontrast CISS imaging independently. RESULTS: On the phantom study, the CISS-3DFT sequence showed a constant increase in signal intensity as the concentration of Gd-DTPA increased. The contrast between the nerves and tumors significantly increased after contrast agent administration (from 0.1 to 9.0 as mean contrast-to-noise ratio). The ability to depict the nerves was also significantly higher for postcontrast CISS-3DFT imaging than for precontrast. CONCLUSION: Although the CISS-3DFT sequence offers similar contrast as other heavily T2-weighted sequences, the signal intensity of contrast-enhanced tumors increased on CISS-3DFT imaging. Contrast-enhanced CISS imaging was valuable for evaluating the seventh and eighth cranial nerves affected by vestibular schwannomas.

Adult↗
PubMedDate not supplied

Detection of p53 mutations in the plasma DNA of patients with ovarian cancer.

Mutation of p53 is one of the most common genetic abnormalities detected in up to 81% of cases of ovarian cancer. To evaluate the use of plasma DNA analysis as a method for somatic mutation screening, we measured the presence of p53 mutations in DNA isolated from plasma and cancer tissue from patients with ovarian cancer. We analyzed the plasma DNA for the presence of p53 mutations (exons 5-8). Of 27 cases of ovarian cancer, 12 cases (44%) had mutations of p53 in cancer tissue. In two of the 12 cases (16.7%), identical mutations were detected in DNA of their preoperative plasma. In our follow-up of the two patients with p53 mutations in their plasma, mutant DNA was undetectable in their plasma after surgery. In one case, the p53 mutation re-surfaced in their plasma 16 months after surgery, and the patient died 2 months later. We have shown that tumor-derived DNA can be detected in the plasma of some patients with ovarian cancer, particularly in those with more advanced stage.

Adolescent↗
PubMedDate not supplied

Hyperventilation activation on EEG recording in childhood.

In 66 children with no neurologic symptoms, we analyzed EEG slowing quantitatively during standardized hyperventilation (HV) activation [respiration rate (RR) of 30/min, threefold increase of VE, and 4-min duration]. Changes in cerebral blood flow (CBF) and velocity were also monitored in right common carotid artery by Doppler ultrasonic method. Decreases in PCO2 and CBF were the fundamental factors producing EEG slowing during HV. The degree of EEG slowing was greater in younger children and well proportional to age with such standardized HV. The decrease in CBF was much greater in younger children at the beginning of HV and may be related to the significant EEG slowing. EEG slowing was not related to the degree of decrease in CBF. The age difference in EEG response to HV in children and adults may be due to the differences in the decrease in the CBF volume and sensitivity of the CNS to the change in CBF.

Adolescent↗
PubMedDate not supplied

High prevalence of infection with hepatitis B and C viruses in patients with hepatocellular carcinoma in Japan.

BACKGROUND/AIMS: Hepatitis B and C viruses are closely associated with hepatocellular carcinoma. We studied the prevalence of infection with either virus in patients with this cancer by examination of sera and tumor tissue. METHODOLOGY: Serum samples obtained before treatment from 330 patients with hepatocellular carcinoma were assayed for antibodies against hepatitis C virus and against hepatitis B surface and core antigen. Tumor tissues from 65 patients were examined for hepatitis B virus RNA. RESULTS: Of the 330 patients, 87 had anti-hepatitis C alone; 161 had anti-hepatitis C and anti-hepatitis B (core); 13 had anti-hepatitis C and anti-hepatitis B (surface); 39 had anti-hepatitis B (surface) alone; and, 19 had anti-hepatitis B (core) alone. Eleven patients had none of these. Hepatitis B virus genes were detected in tumor tissue in all 13 patients with anti-surface antibody, in 21 of 30 patients with anti-core antibody, and in 9 of 22 patients without hepatitis B antibodies. Viral genes were detected in tumor tissue in 5 of 11 patients with neither B nor C virus markers in their sera; viral markers were found in either serum or tumor tissue in 324 of 330 patients (98.2%). CONCLUSIONS: The prevalence of hepatitis B or C virus infection in patients with hepatocellular carcinoma in Japan is extremely high. The prevalence of co-infection with both viruses is also high.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Hyperintensities of the optic radiation on T2-weighted MR images of elderly subjects.

BACKGROUND AND PURPOSE: Although abnormal hyperintensities are frequently observed at or around the optic radiation in elderly subjects, no previous reports have mentioned the clinical significance and pathologic changes of these hyperintensities. We evaluated the hyperintensity patterns of the optic radiation and its surrounding structures on T2-weighted MR images and compared these findings with pathologic observations and visual field measurements. METHODS: High-resolution coronal T2-weighted MR images of 102 consecutive patients (51-84 years old) were evaluated retrospectively for the presence and morphology of hyperintensities of the optic radiation (204 sides) and its surrounding structures. Pathologic specimens were obtained from 25 other patients (60-91 years old) who had died of nonneurologic causes. The histopathologic changes of the optic radiation and its surrounding structures were evaluated and correlated with the MR findings. Finally, MR findings and visual field measurements were correlated in 46 elderly volunteers (70-91 years old). RESULTS: Hyperintensities of the optic radiation or its surrounding structures or both were observed on 125 sides (93%) of 67 patients (61%), and linear/laminar hyperintensity of the optic radiation and the tapetum was the characteristic finding. Eleven (44%) of 25 pathologic specimens exhibited pallor of three anatomic layers (the external sagittal stratum or the optic radiation, the internal sagittal stratum, and the tapetum). No subjects with hyperintensity of the optic radiation had visual field abnormalities. CONCLUSION: Linear/laminar hyperintensity of the optic radiation and tapetum on T2-weighted images is common in elderly subjects, and may reflect differences in the internal structures and in the water content of three anatomic structures. Hyperintensities of this region did not cause visual field abnormalities in a group of elderly volunteers.

Aged↗
PubMedDate not supplied

Stimulation of monocyte iodination and IL-1 production by tannins and related compounds.

Various tannins and related compounds were compared for their ability to stimulate the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood monocytes. The stimulating activity of most of the monomeric and dimeric hydrolyzable tannins was generally higher than that of the trimeric and tetrameric compounds. Compounds that had dehydrohexahydroxydiphenoyl or chebuloyl groups had considerably less activity than those that had other functional groups (hexahydroxydiphenoyl, valoneoyl, dehydrodigalloyl, isodehydrodigalloyl, lactonized valoneoyl, hellinoyl, euphorbinoyl, dehydroeuphorbinoyl or woodfordinoyl group). The methylated derivative, nonacosa-O-methylcoriariin A, was essentially inactive, suggesting the requirement of a phenolic hydroxyl group. Three condensed tannins ((-)-epicatechin 3-O-gallate (ECG)-dimer, ECG-trimer and ECG-tetramer) significantly stimulated both monocyte iodination and their interleukin-1-like factor production. The results suggest the dependence of stimulation of monocyte iodination by tannins and related polyphenols on molecular weight.

Animals↗
PubMedDate not supplied

Stimulation of granulocytic cell iodination by tannins and related compounds.

Tannic acid stimulated the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood polymorphonuclear cells (PMN) and human promyelocytic leukemic HL-60 cells, without affecting the iodination of 9 other cultured cell lines. The stimulation of both PMN and HL-60 cells depended on incubation time and temperature, and was significantly suppressed by myeloperoxidase inhibitors. Among chemically defined natural polyphenols, condensed tannins (epicatechin gallate oligomers) and monomeric and oligomeric hydrolyzable tannins potently stimulated PMN iodination, whereas polyphenols of lower molecular weight (gallic acid, alkyl gallates, epicatechin, epicatechin gallate, epigallocatechin, caffeic acid derivatives and licorice flavonoids) had much less activity. Various synthetic polyphenolic compounds structurally unrelated to tannins also stimulated PMN iodination depending upon their molecular weight, but to a slightly lesser extent. The results suggest that the stimulation activity of tannins and related polyphenols might depend more on their molecular weights than the number of hydroxyl groups on each benzene ring in the molecule, or the presence of sugars or hexahydroxydiphenoyl groups.

Animals↗
PubMedDate not supplied

Rectangular field of view for dynamic MR imaging of sellar and parasellar regions.

The effectiveness and quality of a rectangular field of view (R-FOV) were compared with those of a square FOV (S-FOV) in dynamic MR study of sellar regions. Cranial nerves in the cavernous sinus were identified more clearly with R-FOV. The image quality grading of R-FOV was significantly superior to that of S-FOV.

Cavernous Sinus↗
PubMedDate not supplied

MR imaging of minamata disease: qualitative and quantitative analysis.

Minamata disease (MD), a result of methylmercury poisoning, is a neurological illness caused by ingestion of contaminated seafood. We evaluated MR findings of patients with MD qualitatively and quantitatively. Magnetic resonance imaging at 1.5 Tesla was performed in seven patients with MD and in eight control subjects. All of our patients showed typical neurological findings like sensory disturbance, constriction of the visual fields, and ataxia. In the quantitative image analysis, inferior and middle parts of the cerebellar vermis and cerebellar hemispheres were significantly atrophic in comparison with the normal controls. There were no significant differences in measurements of the basis pontis, middle cerebellar peduncles, corpus callosum, or cerebral hemispheres between MD and the normal controls. The calcarine sulci and central sulci were significantly dilated, reflecting atrophy of the visual cortex and postcentral cortex, respectively. The lesions located in the calcarine area, cerebellum, and postcentral gyri were related to three characteristic manifestations of this disease, constriction of the visual fields, ataxia, and sensory disturbance, respectively. MR imaging has proved to be useful in evaluating the CNS abnormalities of methylmercury poisoning.

Ataxia↗
PubMedDate not supplied

The influence of volatile anesthetics on portwine stain.

To examine the relationship between volatile inhalation anesthetics and the fading of portwine stain (PWS), the study retrospectively investigated the incidence of termination of pulsed dye laser treatment vis-à-vis PWS fade during use of a general inhalation anesthetic in 107 infants and children with facial PWS. The fading of PWS is disadvantageous to the pulsed dye laser treatment. All patients received pulsed dye laser treatment under general anesthesia using one of four kinds of volatile inhalation anesthetics (halothane, enflurane, isoflurane, and sevoflurane). Two hours before the induction of anesthesia, all patients were rectally irrigated. Treatment was discontinued in none of the 44 patients in the halothane group or the 7 patients in the enflurane group; in one of the 29 in the isoflurane group; and in 10 of the 27 patients in the sevoflurane group. The sevoflurane group showed a significantly (P < 0.01) higher incidence of PWS fading. Thus, when using a volatile inhalation anesthetic in combination with pulsed dye laser treatment for PWS, caution should be exercised if sevoflurane is selected, as PWS fading is harmful to the pulsed dye laser.

Anesthesia, General↗
PubMedDate not supplied

Antitumor activity and interleukin-1 induction by tannins.

The relationships between structures, antitumor activities and interleukin-1 (IL-1) induction by fifteen tannins were studies. When tannins (10 mg/kg) were intraperitoneally injected into mice once, 4 days before intraperitoneal inoculation of S-180 cells, tellimagrandin II, rugosin A, hirtellin B, oenothein B and oenothein A, which have only tellimagrandins I or II units in their molecules, had significant antitumor activity. Although casuarictin and its related tannins were ineffective, agrimonin, which is a dimer, had a strong effect, as previously reported. On the other hand, monomeric ellagitannins such as tellimagrandins I and II, rugosin A and casuarictin also increased IL-1 beta production from human peripheral macrophages in vitro by 2-fold over the non-stimulated basal production and oligomeric ellagitannins with strong antitumor activity more potently stimulated the IL-1 beta induction. Other tannins having no antitumor activity induced less IL-beta. This study indicates that oligomeric ellagitannins, which consist of tellimagrandin I or II, casuarictin or their related structure units, have antitumor activity and induce IL-1 beta.

Animals↗
PubMedDate not supplied

Indications for, and effectiveness of, a second hepatic resection for recurrent hepatocellular carcinoma.

BACKGROUND/AIMS: Second hepatic resection (SHR) for recurrent hepatocellular carcinoma (HCC) appears to have a better prognosis than other treatments; however, it is not clear whether this is the result of the procedure, or of the underlying condition of patients undergoing this treatment. MATERIALS AND METHODS: Consecutive hepatic resection for 13 years, many patients suffered from recurrence in the remnant liver. After detection of recurrence, these lesions were treated in various ways including SHR. In this communication, recurrent patients were divided into SHR patients and non-SHR patients. In these two groups, we analyzed clinicopathologically. RESULTS: After 341 curative hepatic resections for HCC, recurrences presented in 193 patients (57%). SHR was performed in 31 patients (16%), while the other 162 patients (84%) underwent other treatments. At first resection, the group did not significantly differ in sex, age, evidence of hepatitis infection, liver function tests, tumor size, presence of portal vein invasion and evidence of histologic cirrhosis. SHR patients had more tumor-free days following first resection than non-SHR patients (p < 0.05). The survival rate following recurrence for SHR patients was better than that of non-SHR patients (p < 0.05). Among the non-SHR patients, 23 patients met criteria for the procedure. Survival rate for the 31 SHR patients also was better than that of these 23 patients (p < 0.05). CONCLUSION: Since SHR is safe, effective, and offers an improved prognosis for recurrent HCC, it should be the treatment of choice whenever possible.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Possible role of radical intensity and oxidation potential for gallic acid-induced apoptosis.

Gallic acid induced apoptotic cell death in human promyelocytic leukemia HL-60 cells. The effect of gallic acid was significantly reduced by blocking the free hydroxyl or carboxyl group with acetyl, methyl, ethyl, n-propyl or isoamyl group. This was paralleled with the decrease in the intensity of both gallate radical and oxidation potential. These data suggest the prooxidant action of gallic acid in the induction of apoptosis. On the other hand, the introduction of larger alkyl groups, such as lauryl or stearyl groups, to the carboxyl group of gallic acid, neither increased the radical intensity nor oxidation potential, but significantly increased its apoptosis-inducing activity. This suggests that the increase in the lipophilicity of the gallate molecule is an another factor which induces apoptosis by an as yet unidentified mechanism.

Antioxidants↗