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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 1,099 records · Page 61Linked to original sources
PubMedDate not supplied

Evaluation of blood flow patterns of true and false lumens in dissecting aneurysms using MR phase-contrast techniques.

The magnetic resonance phase-contrast technique for the measurement of flow velocity and volume in true and false lumens was studied in six patients with chronic dissecting aneurysms. Phase-contrast images were obtained at a level perpendicular to the dissecting aneurysms of the descending aorta. As the maximum diameter of aneurysms increased, the ratio of the cross-sectional area of the false to the true lumen increased and the peak average velocity in the true lumen during systole was decreased. This technique proved invaluable for determining prognosis and operability for this condition.

Aged↗
PubMedDate not supplied

Endoscopic ultrasonography in primary gastric lymphoma: correlation with endoscopic and histologic findings.

To evaluate the potential value of endoscopic ultrasonography in primary gastric lymphoma, we compared endoscopic ultrasonography findings with endoscopic and histologic findings in 15 patients in whom the diagnosis had been established by radiography and endoscopy, including forceps biopsy. The patients were divided into four groups according to the endoscopic ultrasonography findings. The groups included the following: superficially spreading type (six patients), diffusely infiltrating type (three patients), mass-forming type (four patients), and mixed type (two patients). The endoscopic ultrasonography findings correlated well with the endoscopic, macroscopic, and histologic findings. The histologic findings in nine patients with the endoscopic ultrasonography superficially spreading type or diffusely infiltrating type revealed B-cell lymphoma arising from mucosa-associated lymphoid tissue, which shows slowly infiltrative growth. In four patients with the endoscopic ultrasonography mass-forming type, on the other hand, the tumor histologic finding consisted of diffuse large-cell or diffuse mixed-cell type. Our results indicate that endoscopic ultrasonography may provide information helpful for the management of primary gastric lymphoma.

Adult↗
PubMedDate not supplied

Fate of PCDF/PCB congeners and change of clinical symptoms in patients with Yusho PCB poisoning for 30 years.

Two mass-food poisonings called Yusho and Yucheng occurred in Japan and Taiwan in 1968 and 1979, respectively. Blood samples from five Yusho patients and three Yucheng patients were collected several times from 1982 to 1998 and from 1980 to 1995, respectively, and analyzed for polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) congeners. Fat base concentrations of 2,3,4,7,8-penta-CDF in the Yusho patients, which were responsible for about 70% of the dioxin toxicity, are estimated to be decreased from 60 ppb in 1969 to 800 ppt in 1997 with the median half-life of 2.9 years in the first 15 years after onset and 7.7 years in the next stage of 15 years. Typical Yusho symptoms of acneiform eruption, dermal pigmentation and increased eye discharge were very gradually recovered with lapse of several years. However, enzyme and/or hormone-mediated signs of high serum triglyceride, high serum thyroxin, immunoglobulin disorder and others are persistently maintained for 30 years.

Acne Vulgaris↗
PubMedDate not supplied

Concentrations of PCBs, PCDFs and PCDDs in the blood of Yusho patients and their toxic equivalent contribution.

Yusho blood and control serum were collected in around 1991 and analyzed for congeners of PCDDs, PCDFs and PCBs. In Yusho blood, TEQ was mainly contributed by 2,3,4,7,8-penta-CDF (77-248 ppt), 1,2,3,4,7,8-hexa-CDF (15-37 ppt) and 2,3,3',4,4',5-hexa-CB (16-77 ppt). Total TEQ in Yusho blood (185-441 ppt) was only 3-14 times higher than that of control serum (31-61 ppt). It is notable that the concentrations of 3,3',4,4',5-, 2,3,3',4,4'- and 2,3',4,4',5-penta-CBs in Yusho blood were comparable to or lower up to 3-5 times than those in control blood.

Benzofurans↗
PubMedDate not supplied

Reduction of serum thyroxine concentrations by methylsulfonyl metabolites of tetra-, penta- and hexachlorinated biphenyls in male Sprague-Dawley rats.

Male Sprague-Dawley rats received four consecutive intraperitoneal doses of nine methylsulfonyl (MeSO2) metabolites of tetra-, penta- and hexachlorinated biphenyls (tetra-, penta- and hexaCBs) to determine their effects on thyroid hormone levels. Nine MeSO2 metabolites, major MeSO2-PCBs detected in human milk, liver and adipose tissue, were 3-MeSO2-2,2',4',5-tetraCB (3-MeSO2-CB49), 3-MeSO2-2,3',4',5-tetraCB (3-MeSO2-CB70), 3-MeSO2-2,2',3',4',5-pentaCB (3-MeSO2-CB87), 3-MeSO2-2,2',4',5,5'-pentaCB (3-MeSO2-CB101), 4-MeSO2-2,2',4',5,5'-pentaCB (4-MeSO2-CB101), 3-MeSO2-2,2',3',4',5,6-hexaCB (3-MeSO2-CB132), 3-MeSO2-2,2',3',4',5,5'-hexaCB (3-MeSO2-CB141), 3-MeSO2-2,2',4',5,5',6-hexaCB (3-MeSO2-CB149) and 4-MeSO2-2,2',4',5,5',6-hexaCB (4-MeSO2-CB149). All nine MeSO2 metabolites (20 micromol/kg once daily for four days) reduced serum total thyroxine levels (16-44%) at a much lower dose than phenobarbital (431 micromol/kg once daily for four days) on days 2, 3, 4 and 7 after the last dosage. Total triiodothyronine level was reduced 37% by treatments with 3-MeSO2-CB49 and 3-MeSO2-CB149 at day 7, but increased 35% and 38% by 3-MeSO2-CB70 and 4-MeSO2-CB101 at days 3 and 4, respectively. The reductions in thyroxine levels led to an increase in thyroid-stimulating hormone levels by 3-MeSO2-CB49, 3-MeSO2-CB87, 3-MeSO2-CB101, 3-MeSO2-CB132, 3-MeSO2-CB141, 3-MeSO2-CB149 and 4-MeSO2-CB149. A 30% increase in thyroid weight was produced by 3-MeSO2-CB101 and 3-MeSO2-CB141 treatments. Total cytochrome P450 content and the activity of 7-pentoxyrosorufin O-dealkylase were increased by all seven 3-MeSO2-PCBs. 3-MeSO2-CB49, 3-MeSO2-CB87, 3-MeSO2-CB101 and 3-MeSO2-CB132 also increased the activity of 7-ethoxyresorufin O-dealkylase. Thus, it is likely that all nine tested MeSO2 metabolites could influence thyroid hormone metabolism. The results show that tested 3- and 4-MeSO2 metabolites of tetra-, penta- and hexaCBs reduce thyroid hormone levels in rats, suggesting that the metabolites may act as endocrine-disrupters.

Animals↗
PubMedDate not supplied

Mechanism of bone destruction due to middle ear cholesteatoma as revealed by laser-Raman spectrometry.

In an investigation of the mechanism of bone destruction caused by chronic otitis media complicated with cholesteatoma, both the processes of demineralization and remineralization were studied in an animal model and clinically at the molecular level, using a laser-Raman spectrometer. From this investigation, it is proposed that the mechanism of bone destruction associated with cholesteatoma is a form of demineralization.

Adult↗
PubMedDate not supplied

Postrevascularization recovery of fatty acid utilization in ischemic myocardium: a randomized clinical trial of potassium channel opener.

BACKGROUND: Abnormal fatty acid metabolism persists in hibernating myocardium, even after reperfusion. This study was designed to determine whether the K+ channel opener, nicorandil, improves fatty acid utilization after percutaneous transluminal coronary angioplasty (PTCA). METHODS: Patients undergoing elective PTCA were randomly assigned to treatment (group N, n = 26) or control groups (group C, n = 22). Group N received intracoronary and intravenous nicorandil during PTCA. Myocardial fatty acid use and perfusion were quantitatively evaluated by means of iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid single photon emission computed tomography (I-123 BMIPP SPECT) and thallium-201 (Tl-201) imaging before PTCA, 72 hours after PTCA, and 3 months after PTCA. Left ventricular function was also evaluated by means of contrast ventriculography before and 3 to 6 months after PTCA. RESULTS: The 1-123 BMIPP defect score in group N significantly decreased, from 28%+/-13% to 20%+/-20% after PTCA and to 18%+/-17% 3 months later. In contrast, the I-123 BMIPP defect score in group C increased from 28%+/-20% to 36%+/-15% (P<.05 versus group N) after PTCA, then returned to 28%+/-17% (P<.05 versus group N) 3 months after PTCA. Recovery of left ventricular function paralleled the recovery of I-123 BMIPP uptake. CONCLUSIONS: Nicorandil improves the recovery of myocardial fatty acid utilization and cardiac function after PTCA. K(ATP) channel activation may have a protective effect during coronary artery occlusion and improve subsequent recovery.

Adult↗
PubMedDate not supplied

Analytical method for minute amounts of polychlorinated biphenyl methylsulfones from fatty tissue.

Five methylsulfone (MSF) derivatives of polychlorinated biphenyls (PCBs) containing 2 to 6 chlorine atoms were synthesized and fortified in bovine fat. The samples were saponified in sodium hydroxide ethanol solution, extracted with n-hexane after dilution with a double volume of water, and chromatographed on a column of silica gel eluting successively with n-hexane and 5% and 50% diethyl ether in n-hexane. The third eluate was partitioned between n-hexane and concentrated sulfuric acid and back-extracted with n-hexane from 70% sulfuric acid solution. The extract was further partitioned between n-hexane and 90% acetonitrile and back-extracted with n-hexane from 20% acetonitrile solution. The final extract was analyzed by gas chromatography with electron capture detection. Recovery of the MSF-PCBs from the bovine fat by the clean-up procedure was greater than 93% in most cases. The method can determine 5 ng and 100 ng each of the MSF-PCBs in a 5-g fatty sample with ca. 10 and 6% precision, respectively.

Acetonitriles↗
PubMedDate not supplied

Measurement of arterial tracer concentrations from cardiac PET images.

OBJECTIVE: Cardiac PET imaging offers the potential capability for the noninvasive measurement of arterial input function. This capability is somewhat limited, however, because of partial volume and spillover effects. The purpose of this study was to validate arterial tracer concentration measurements using PET images by assigning a region of interest (ROI) to the left ventricle, left atrium (LA), and ascending aorta. MATERIALS AND METHODS: We selected [11C]CO and [13N]ammonia as tracers, because the activity of [11C]CO is primarily in the blood pool and that of [13N]ammonia primarily in myocardial tissue. Six [11C]CO and 11 [13N]ammonia PET scans were obtained in 17 subjects. Arterial tracer concentrations determined by PET were compared with those measured by well counting of arterial blood sampling obtained at the midpoint of each image acquisition. RESULTS: Arterial tracer concentrations as determined by LA-PET imaging correlated closely with those measured by blood sampling (r = 0.996, slope = 1.00 for [11C]CO; r = 0.841, slope = 0.974 for [13N]ammonia). Partial volume and spillover effects were minimized by assigning an ROI to the LA. CONCLUSION: Arterial tracer concentrations can be measured noninvasively with cardiac PET.

Adolescent↗
PubMedDate not supplied

Apoptosis in glomerular endothelial cells during the development of glomerulosclerosis in the remnant-kidney model.

Capillary obsolescence with subsequent glomerulosclerosis is a common finding in most progressive glomerular diseases. In this study we investigated apoptosis, focusing on glomerular endothelial cells during the development of glomerulosclerosis in five-sixths nephrectomized rats for 6 months. Apoptosis was recognized by light and electron microscopy. Biochemical labeling of apoptosis was morphologically confirmed by in situ end labeling of fragmented DNA using terminal deoxynucleotidyltransferase. Glomerular endothelial cells were identified by electron microscope and immunostaining for thrombomodulin which is known to be an endothelial cell surface glycoprotein. Glomerular hypercellularity occurred by month 2, peaking by month 3, and an extracellular matrix accumulation was evident by month 3. Subsequently, most of the glomeruli progressed to diffuse sclerosis by months 4-6. During the progression of the disease, the glomerular endothelial cells decreased in number and finally could not be detected in the sclerotic lesion, and apoptotic cells apparently increased in number in the lesion. Significant apoptosis was present from month 3, thereafter it gradually increased to peak by month 6. Double immunostaining for apoptosis and thrombomodulin demonstrated that apoptosis occurred in the glomerular endothelial cells as well as in mesangial cells and infiltrating cells. The number of glomerular endothelial cells with apoptosis increased with the development of glomerulosclerosis, and maximum expression was observed by month 6. We conclude that the depletion of glomerular endothelial cells is associated with apoptosis in the remnant-kidney model, and apoptosis in glomerular endothelial cells may contribute to the development of glomerulosclerosis.

Animals↗
PubMedDate not supplied

Programmed cell death in the mouse cochleovestibular ganglion during development.

Programmed cell death (PCD) is as essential to development as is cell proliferation. Our objective was to elucidate the spatiotemporal occurrence of PCD during the development of the cochleovestibular ganglion. We performed a time-sequence study on the distribution of in situ PCD, apoptosis, during the development of the mouse cochleovestibular ganglion by using the TUNEL method to detect apoptosis histochemically. Apoptosis in the cochleovestibular ganglion was observed from the 11.5th gestational day (GD) to the 18. 5th GD. Apoptosis was seen most extensively in the vestibular ganglion cells at the 13.5th GD, while in the spiral ganglion cells apoptosis was maximal between the 15.5th and 16.5th GD. Because these times of peak apoptotic activity almost exactly corresponded to the events of innervation and terminal mitosis of the cochleovestibular ganglion cells, we infer that PCD is involved in the innervation and modulates the number of cochleovestibular ganglion cells overproduced by terminal mitosis.

Animals↗
PubMedDate not supplied

Increased serum levels of circulating intercellular adhesion molecule-1 in patients with myocarditis.

Levels of circulating intercellular adhesion molecule-1 (cICAM-1) were measured by ELISA in the sera of 21 patients with unexplained cardiac dysfunction. By evaluating the biopsy or autopsy specimens, they were classified into two groups: a myocarditis group (n = 8) and a nonmyocarditis group (n = 13). Levels of cICAM-1 were significantly higher in the myocarditis group (p < 0.01). Increased levels of cICAM-1 (> 2 SD above the control mean) were detected in 6 of 8 patients in the myocarditis group. Therefore, the detection of increased levels of cICAM-1 could be a useful marker for myocarditis.

Adult↗
PubMedDate not supplied

Laryngeal zoster with unilateral laryngeal paralysis.

The case of a 60-year-old man with a unilateral laryngeal mucosal lesion and complete left vocal cord paralysis is reported. The lesion localized to the left side of the larynx covered the laryngeal vestibule, arytenoid, false vocal cord and true vocal cord, but did not extend to the hypopharynx or oropharynx. Enzyme immunoassay for varicella-zoster virus (VZV) led to a diagnosis of VZV infection.

Antibodies, Viral↗
PubMedDate not supplied

Effects of single and repeated administrations of Toki-shakuyaku-san on the concentrations of brain neurotransmitters in mice.

The amounts of monoamine-related substances (NE, MHPG, DA, DOPAC, HVA, 5-HT, and 5-HIAA and acetylcholine (ACh) in the cerebral cortex, corpus striatum and hippocampus of mice treated orally with a powdered extract of Toki-shakuyaku-san (TSS) were measured using the HPLC-ECD method. Single administration of TSS at 50 mg/kg decreased the content of NE in the hippocampus, but increased the contents of DA, DOPAC and HVA. Single administration of TSS at 50 mg/kg increased the contents of DA and HVA in the cerebral cortex and those of DA, DOPAC and HVA in the hippocampus, but decreased the content of NE. Repeated administration (twice a day, for 14 days) of TSS at 50 mg/kg increased the contents of DA, DOPAC and 5-HIAA in the cerebral cortex, while 500 mg/kg increased the contents of NE, MHPG, DOPAC, 5-HT and 5-HIAA in the cerebral cortex, and the NE and DA in the corpus striatum. With regard to ACh content, single and repeated administrations of TSS at 50 and 500 mg/kg had no influence in the three regions of mouse brain. These results suggest that single administration of TSS stimulates the function of the dopaminergic nervous system in the hippocampus in mice and inhabits the function of the adrenergic nervous system, and that repeated administration of TSS stimulates the function of the adrenergic, dopaminergic and serotonergic nervous systems in the cerebral cortex. TSS, however, did not show any influence on the brain ACh content in mice.

Acetylcholine↗