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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 451 records · Page 25Linked to original sources
PubMed1992

Polymerase chain reaction for the detection of the varicella-zoster genome in ocular samples from patients with acute retinal necrosis.

We used the polymerase chain reaction to detect the virus genome in ocular samples from patients with clinically diagnosed acute retinal necrosis. Four samples from four patients with acute retinal necrosis, and five samples from three patients with other ocular diseases (sarcoidosis, rhegmatogenous retinal detachment, and epiretinal membrane of unknown origin) were evaluated. The samples consisted of aqueous humor, vitreous, or subretinal fluid. Primers were specific for varicella-zoster virus, herpes simplex virus, or cytomegalovirus. The varicella-zoster virus genome was detected in three of the four samples from patients with acute retinal necrosis. Among these three positive samples, two had PstI-site-less point mutation, strains that have been described only in Japan and of low prevalence. Samples from patients with diagnoses other than acute retinal necrosis yielded negative results when varicella-zoster virus primer was used. No sample was positive for herpes simplex virus or cytomegalovirus primers.

Adult↗
PubMed1992

[MR imaging of intraocular lesions--a comparison with CT].

Thirty-two intraocular lesions were studied with magnetic resonance (MR) imaging and computed tomography (CT). These lesions included retinoblastoma (n = 11), uveal melanoma (n = 6), metastatic choroidal tumor (n = 3), choroidal hemangioma (n = 2), retinochoroiditis (n = 6) and Coats' disease (n = 4). MR imaging was superior to CT in the depiction of intraocular masses and retinal detachment. Gd-DTPA enhanced MR imaging was more useful than contrast enhanced CT in evaluating the contrast enhancement of intraocular tumors. Differential diagnosis of intraocular tumors was difficult with both MR imaging and CT. Intratumoral calcification was noticed on CT in nine cases of retinoblastoma. It was concluded that MR imaging, including contrast enhancement study, is more useful than CT in the evaluation of intraocular lesions, except for calcification, and contrast enhanced CT may be unnecessary in the diagnosis of intraocular lesions.

Eye Diseases↗
PubMed1992

[Determination of vertebral fracture threshold by measuring bone mineral content in the lumbar vertebrae].

Bone mineral density (BMD) in the lumbar vertebrae (L2-L4) was assessed by dual energy X-ray absorptiometry (DEXA: QDR-1000), and the values obtained were compared with the frequency of vertebral fracture as assessed by spinal X-ray photographs. Patients with spondylosis or scoliosis, which affect BMD values, were excluded from the study. An essentially linear correlation was observed between the frequency of vertebral fracture and lumbar BMD values: no vertebral fractures were observed in those whose BMD more than 0.8 g/cm2, whereas the frequency of fracture was 100% in patients whose BMD was less than 0.45 g/cm2. Thus, measurement of lumbar vertebrae by DEXA would be very useful in predicting vertebral fractures.

Absorptiometry, Photon↗
PubMed1992

HTLV-I infection in patients with autoimmune thyroiditis (Hashimoto's thyroiditis).

To investigate the possible relationship of HTLV-I virus infection to autoimmune thyroid disease, we examined, firstly, the frequency of HTLV-I seropositivity among patients with Hashimoto's thyroiditis and, secondly, the frequency of Hashimoto's thyroiditis in patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). Of 144 patients with Hashimoto's thyroiditis in the Tokushima and Kochi Prefectures, Japan, 9 (6.3%) were positive for serum HTLV-I virus antibody 2 of whom were confirmed histologically to have Hashimoto's thyroiditis. This percentage is significantly higher (P < 0.01) than the estimated prevalence (2.2%) of HTLV-I carriers among the general population in this region. Of 9 patients with HAM/TSP, 3 (33.3%), including 2 biopsy-proven cases, had evidence of Hashimoto's thyroiditis. This proportion is apparently much higher than the prevalence (1.7%) of Hashimoto's thyroiditis in the general population. These findings suggest that HTLV-I virus may be related to the development of Hashimoto's thyroiditis.

Adult↗
PubMed1992

MR imaging and angiography of cerebral venous angiomas associated with brain tumors.

MR study of 6 patients with concurrent venous angioma and brain tumor revealed that in 2 of the 6 cases, the draining vein of the venous angioma was located near to the tumor and was displaced by the tumor. Two of the 6 venous angiomas were too small to visualize prior to contrast enhancement, but could be detected following administration of Gd-DTPA. Angiography was required for definitive diagnosis of the venous angiomas. When a venous angioma is suspected or is detected incidentally, especially when very near a brain tumor, angiography should be considered before performing surgery to avoid surgical complications. Otherwise, ligation of the vein draining the venous angioma may lead to venous infarction.

Adolescent↗
PubMed1992

Characteristic findings of hepatocellular carcinoma: an evaluation with comparative study of US, CT, and MRI.

The sensitivity, specificity, and accuracy of ultrasonography (US), dynamic incremented computed tomography (CT) with delayed phase imaging, and magnetic resonance imaging (MRI) with or without Gd-DTPA were studied for detecting the characteristic appearances of hepatocellular carcinomas (HCC): fibrous capsules, fibrous septa, and mosaic appearances. Results were prospectively evaluated in 30 patients who subsequently underwent hepatic lobectomies or segmentectomies. Pathologic evaluations of the resected liver specimens demonstrated fibrous capsules in 20 tumors (66.7%), fibrous septa in 13 tumors (43.3%), and mosaic appearances in 19 tumors (63.3%). The accuracies for fibrous capsules were 71.4% (20 of 28) for US, 81.5% (22 of 27) for CT, and 92.3% (24 of 26) for MRI. The accuracies for fibrous septa were 57.1% (16 of 28) for US, 59.3% (16 of 27) for CT, and 73.1% (19 of 26) for MRI. The accuracies for mosaic appearances were 71.4% (20 of 28) for US, 51.9% (14 of 27) for CT, and 69.2% (18 of 26) for MRI. Gd-DTPA administered MRI showed higher accuracies than did conventional MRI for all manifestations. In conclusion, the fibrous capsules of HCCs were readily detected by CT and MRI. Gd-DTPA administration demonstrated an advantage in clarifying fibrous capsules, as well as fibrous septa and mosaic appearances.

Aged↗
PubMed1992

Prognostic significance of location of lymph node metastases in colorectal cancer.

The prognostic value of stage of lymph node metastases was evaluated in 357 patients who underwent curative resection for colorectal cancer. Subdivision of Dukes C patients according to the number of positive nodes revealed that the five-year disease-free survival rate (5DFS) was 63 percent in the patients with one to three nodes and 53 percent in those with four or more nodes (not significantly different). Classification according to the location revealed that 5DFS was 70 percent in those who had only local node metastases (n1+), compared with 40 percent in those who had distant node metastases along the major vessels (n2+) (P < 0.001). Twelve of 38 n2+ patients had only one distant node metastasis with no local node involvement (skip metastasis). They had lower 5DFS than the n1+ patients who had three or more positive local nodes (35 percent vs. 57 percent). We conclude that the location, rather than the number, of nodal metastases has a higher impact on prognosis in colorectal cancer patients.

Colorectal Neoplasms↗
PubMed1992

Unusual renal oncocytomas: pathologic and CT correlations.

The unusual features of nine oncocytomas in five patients are reported herein. These include multiplicity in two, bilaterality in two, calcification in one, and association with renal cell carcinomas in three patients. Radiologists should be aware of these findings for this benign renal neoplasm.

Adenoma↗
PubMed1992

Regional cerebral glucose metabolism in patients with Parkinson's disease with or without dementia.

By means of positron emission tomography, the cerebral glucose metabolism in 5 patients with Parkinson's disease with dementia was compared with that in 9 patients without dementia, and that in 5 normal volunteers. The metabolic rates for glucose were measured by placing one hundred regions of interest. In the demented patients, cerebral glucose metabolism was diffusely decreased compared with that of the non-demented patients and the normal controls. The most significant decrease in glucose metabolism was observed in the angular gyrus (49.7% of the normal controls). The glucose metabolism in the cingulate, pre- and postcentral, occipital and subcortical regions was relatively spared (62.1 to 85.5% of the normal controls). In the patients without dementia, the glucose metabolism in each region was not significantly different from that in the normal controls. These results suggest that diffuse glucose hypometabolism in the cerebral cortex may correlate with that of patients with Parkinson's disease with dementia.

Aged↗
PubMed1992

Increased striatal 18F-dopa uptake and normal glucose metabolism in idiopathic dystonia syndrome.

Striatal 18F-Dopa uptake and glucose metabolism were studied by positron emission tomography with 6-L-[18F]fluorodopa and [18F]fluorodeoxyglucose, respectively, in 8 patients with idiopathic dystonia. Patients with abnormal findings on the brain CT and MRI were excluded from this study. The clinical diagnosis consisted of torsion dystonia in 3 patients, focal dystonia limited in the arm in 3 and cervical dystonia (spasmodic torticollis) in 2. The 18F-Dopa uptake, corrected by nonspecific retention in the cerebellum, at 120 min post-administration was evaluated, and increased 18F-Dopa uptake in the putamen and in the caudate head was observed in the patients with idiopathic dystonia compared to the normal controls. The striatal glucose metabolism in the patients with idiopathic dystonia showed no difference with the normal controls. These findings suggest that pathogenetic mechanism of idiopathic dystonia involves increased presynaptic activity of the dopaminergic system in the striatum.

Adult↗
PubMed1992

Fetal development of mice following intrauterine exposure to a static magnetic field of 6.3 T.

The study was undertaken to investigate possible teratogenic effects of a high magnetic field on fetal development in mice. Eighty-four pregnant CD-1 mice (ICR) were exposed to a static magnetic field of 6.3 T for 1 hr a day from day 7 through day 14 of gestation, a period corresponding to major organogenesis. Fifty mice served as controls. Dams were sacrificed on day 18 of gestation. Fetuses were examined for both external and skeletal abnormalities. No significant differences between exposed and control groups were observed regarding litter size, fetal weight, intrauterine mortality rate, or external and skeletal anomalies. The effects of static magnetic field of 6.3 T on the parameters studied appear negligible.

Animals↗
PubMed1992

Synthesis and biodistribution of a fluorine-18 labeled analogue of D-talose: 2-deoxy-2-[18F]fluoro-D-talose.

A fluorine-18 labeled analogue of D-talose, 2-deoxy-2-[18F]fluoro-D-talose ([18F]FDT), was synthesized via nucleophilic fluorination with [18F]fluoride ion and its biodistributions in animals were examined. Radiofluorination of benzyl 3,5,6-tri-O-benzyl-2-O-(trifluoromethanesulfonyl)-alpha-D-galac tof uranoside (5) with aminopolyether supported potassium [18F]fluoride (K18F/Kry222) in acetonitrile followed by deprotection of the [18F]fluorinated intermediate (6) with boron tribromide in CH2Cl2 gave [18F]FDT in an average radiochemical yield of 29% with a radiochemical purity greater than 98%. Biodistribution studies of [18F]FDT in mice bearing fibrosarcoma showed the highest uptake of radioactivity in the liver (34.9% dose/g), followed by the kidney (15.9%dose/g), the small intestine (12.9%dose/g) and fibrosarcoma (5.7%dose/g), at 30 min after i.v. administration. Although the radioactivity in the kidney and small intestine decreased with time, the uptake in the liver and the tumor slightly increased until 120 min. The high liver uptake of [18F]FDT was also observed in normal rats and this uptake was strongly inhibited by co-administration of D-galactose. These preliminary results suggest that [18F]FDT might be metabolized through the galactose metabolic pathway as analogously observed with 2-deoxy-2-[18F]fluoro-D-galactose which is an isomer with respect to carbon-2 of [18F]FDT, and that it may be another candidate for studying liver function by positron emission tomography.

Animals↗
PubMed1992

Daily intakes of 232Th and 238U in Japanese males.

Diet samples were collected by a duplicate portion method from 31 locations in Japan and were analyzed by inductively coupled plasma mass spectrometry. Average daily intakes per adult male were estimated at 1.7 mBq for 232Th and 8.8 mBq for 238U.

Adult↗
PubMed1992

Rapid myocardial perfusion imaging with 99Tcm-teboroxime and a three-headed SPECT system: a comparative study with 201Tl.

99Tcm-teboroxime is a new myocardial perfusion agent with a high first pass extraction and rapid myocardial washout. The usefulness of 99Tcm-teboroxime was evaluated for detection of myocardial ischaemia using a three-headed single photon emission tomography (SPECT) system which allows for rapid data acquisition. The subjects consisted of 14 patients, including seven with ischaemic heart disease, four with cardiomyopathy and three others. After the 99Tcm-teboroxime injection, dynamic data was collected every minute for 15 min with continuous rotation. High-quality SPECT images could be obtained by reconstructing the serial scans from 2 to 8 min. The sensitivity, specificity and accuracy of the 99Tcm-teboroxime study for the detection of the ischaemic region were not significantly different from those of the 201Tl study. Myocardial clearance was slow in the ischaemic lesion and in the myocardium of cardiomyopathy patients, while the coronary angiograms did not show any abnormality. These results therefore indicate that the rapid SPECT imaging and myocardial clearance of 99Tcm-teboroxime obtained with a three-headed SPECT system were useful for the detection of myocardial ischaemia.

Adolescent↗
PubMed1992

Heterogeneity of S-layer proteins of Lactobacillus acidophilus strains.

An S-layer (surface regular array) was found in the cell wall from six out of ten strains of Lactobacillus acidophilus examined by electron microscopic observations. All of the six strains which were shown to carry the S-layers belonged to the deoxyribonucleic acid (DNA) homology group A, but not to B, which had been classified by Johnson et al (Int. J. Syst. Bacteriol. 30: 53-68, 1980). On the other hand, the other four strains which possessed no S-layers were in the homology group B. The apparent molecular weights of the S-layer proteins ranged from 41 to 49 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Of the S-layer proteins from the six strains, three were susceptible to chemical cleavage with N-chlorosuccinimide, giving different peptide maps. All of the six S-layer proteins were fragmented by limited proteolysis with Staphylococcus aureus V8 protease, and gave markedly different peptide patterns by the subsequent peptide mapping analysis, except that the peptide maps of the S-layer proteins from the two strains which were in the same subgroup were identical.

Bacterial Outer Membrane Proteins↗
PubMed1992

Monoclonal antibodies against human alpha-fetoprotein more reactive to cell-surface alpha-fetoprotein than to free alpha-fetoprotein.

This paper describes the finding of monoclonal antibody (MoAb) more reactive to cell-surface alpha-fetoprotein (AFP) than to free AFP by using a simple in vitro system. Twelve mouse MoAbs, ten IgG1, one IgG2a and one IgG2b, against human AFP from hepatocellular carcinoma were obtained by the cell fusion technique. Each hybridoma supernatant was assayed by enzyme-linked immunosorbent assay (ELISA) to solid-phase AFP. The assay results showed that two MoAbs, 67D and 80G, were most reactive to AFP. 80G had a higher affinity constant than 67D, while the both reactions were similarly difficult to inhibit by free AFP in ELISA. 67D and 80G reacted with AFP on the surface of ethanol-fixed cells from the human hepatoma cell line HuH-7 and this reaction was also difficult to inhibit by free AFP in Cell ELISA. Furthermore, Western blot analysis showed that 67D and 80G were more reactive to membrane-bound AFP than other antibodies. These findings first suggest that there could be anti-AFP MoAbs preferably binding to cell-surface AFP rather than to serum AFP.

Antibodies, Monoclonal↗
PubMed1992

[Quantitative analyses of the normal throat flora of children with upper respiratory tract infections].

Relationship between the normal throat flora and pathogenic bacteria recovered from the throat in 139 children with upper respiratory tract infections in winter were studied using quantitative analyses. Pathogenic bacteria examined include S. pyogenes, H. influenzae, S. aureus, and S. pneumoniae, and the normal floras include alpha-streptococci, gamma-streptococci, Neisseria species, and Micrococci. Children with S. pyogenes in their throats (S. pyogenes group) were examined with anti-streptococcal antibodies such as anti-streptolysin O, anti-streptokinase, and anti-deoxyribonuclease B. Eighty seven pathogenic bacteria were recovered from 72 children (51.8%) out of 139. S. pyogenes and S. pneumoniae groups showed significantly lower alpha-streptococci and gamma-streptococci in incidence of appearance when compared with children with the no pathogenic bacteria in their throats (no bacteria group). H. influenzae group showed significantly lower gamma-streptococci and higher Neisseria sp. in incidence of appearance compared with the no bacteria group. Positive cases for anti-streptococcal antibodies showed a significantly lower alpha-streptococci in number compared with negative cases for antibodies and the no bacteria group, and a significantly lower gamma-streptococci in incidence of appearance compared with the no bacteria group. These data suggest that the normal throat flora may have a role in prevention of colonization by the pathogenic bacteria in vivo, as were shown in vitro by many authors, and that the quantitative analysis of the normal flora is useful because this methodology might reveal whether the bacteria recovered from the throat show the pathogenicity.

Adolescent↗