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Biomedical subjects

J Itoh

Publications and source records attributed to J Itoh.

At least 109 records · Page 6Linked to original sources
PubMed1990

Extracranial metastases of malignant ependymoma--case report.

A case of malignant ependymoma with extracranial metastases is reported. A 59-year-old male was admitted to our hospital with vomiting and ataxia. Following computed tomographic (CT) scanning indicating a ring-like enhanced mass in the cerebellum, the tumor was subtotally removed in December, 1985. Histological diagnosis was malignant ependymoma. A second operation was performed in February, 1987, due to recurrence of the tumor in the fourth ventricle. Postoperative radiation therapy at a total dose of 7780 rads was given over 2 years. Eleven months after radiation therapy was completed, he reported cough and multiple skin metastases. Chest x-rays showed metastases at the right hilus. Repeated CT scans revealed separate frontal cerebral metastatic tumors. He died of respiratory insufficiency. Extracranial metastases of infratentorial ependymoma to the skin and lung are rare pathological entities.

Cerebral Ventricle Neoplasms↗
PubMed1990

MK4588, a new antibiotic related to xanthocillin.

A new antibiotic, MK4588, structurally related to xanthocillin, was isolated from the culture broth of Leptosphaeria sp. L-179. Antibiotic MK4588 exhibited inhibitory activity against a limited range of Gram-positive and Gram-negative bacteria. The antibiotic was degraded by alkali to a more active product. The structures of MK4588 and the degradation product were determined to be (1R*,6S*,7S*)-7-(Z)-(1-isocyano-2-(4-methoxyphenyl]ethenyl-1-hydro xy-7- isocyanobicyclo[4,2,0]oct-2-en-4-one and (Z)-2,3-diisocyano-1-(4-methoxyphenyl)buta-1,3-diene, respectively, by NMR spectral analyses coupled with X-ray crystallographic analysis of MK4588.

Anti-Bacterial Agents↗
PubMed1990

[Convulsive seizures and heterotopic gray matter; report of two cases].

We reported CT and MRI findings of heterotopic gray matter in two patients with intractable convulsive seizures. CT demonstrated space-occupying but non-expansive lesions isodense with the cortical gray matter adjacent to the body of the lateral ventricle. These lesions were not enhanced with contrast infusion. MRI was performed in one case in which the lesion was isointense with the cortical gray matter.

Brain Neoplasms↗
PubMed1989

2-Deoxy-2-[18F]fluoro-D-galactose as an in vivo tracer for imaging galactose metabolism in tumors with positron emission tomography.

The feasibility of 2-deoxy-2-[18F]fluoro-D-galactose ([ 18F]FdGal) for imaging galactose metabolism in tumors with positron emission tomography (PET), was investigated using two hepatomas, Yoshida sarcoma, or glioma in rats, and mouse mammary carcinoma. In hepatoma-bearing rats the highest uptake of [18F]FdGal was observed in the liver followed by the kidney and tumor. The tumor uptake increased with time, and the high uptake ratios of tumor to organ were observed except for the liver and kidney. Tumor uptake was also measured in all tumors. As main metabolites in all tumors, [18F]FdGal 1-phosphate and UDP-[18F]FdGal were found by HPLC. Two hepatomas showed a slightly higher uptake and a larger percentage of UDP derivative than the other three tumors. By autoradiography the brain tumor was visualized clearly. These results indicate that [18F]FdGal has potential as a tracer for imaging galactose metabolism in tumors with PET.

Animals↗
PubMed1989

In vivo assessment of 6-deoxy-6-[18F]fluoro-D-galactose as a PET tracer for studying galactose metabolism.

The potential of 6-deoxy-6-[18F]fluoro-D-galactose (6-[18F]FdGal) as an in vivo tracer for studying galactose metabolism in tumors and liver was investigated. High uptake and rapid clearance of the radioactivity were observed in many organs of mice after i.v. injection of the tracer. D-Galactose loading did not affect liver uptake. Three experimental tumors showed a slightly higher uptake than other tissues, and rat brain tumor was clearly visualized by autoradiography. However, the radioactivity in tumors decreased rapidly. In the liver, a significant amount of the tracer was found in a galactonate form, while this oxidation was a minor metabolic pathway in the tumors. In both tumor and liver tissues, small amounts of the tracer were incorporated into macromolecular glycoconjugate via phosphate and uridylate forms as intermediate precursors. These results indicate that 6-[18F]FdGal is not suitable for studying galactose metabolism in vivo because of the low affinity of the tracer for the metabolism.

Animals↗
PubMed1989

Effects of synthetic salmon calcitonin on C cells of the thyroid.

The effects of long-term administration of synthetic salmon calcitonin (TZ-CT) on thyroid C cells of rats were evaluated immunohistochemically and electron microscopically. Low dose (0.075, 0.75 and 7.5 IU/kg/day) administration caused no significant changes in the C cell population, whereas high doses (30 and 120 IU/kg/day) caused C cell suppression. The area ratio of C cells to total cells in the thyroid was measured on sections immunoperoxidase stained for calcitonin. The average C cell ratio was compared among the experimental groups. This morphometric analysis of the high-dose and control groups confirmed the differences in C cell populations statistically (30 IU/kg vs. control, p less than or equal to 0.05; 120 IU/kg vs. control, p less than or equal to 0.05). The suppressive effect of TZ-CT on C cells was reversible after cessation of administration for one month. Electron microscopic examination on the C cells in the high-dose groups revealed no particular ultrastructural differences. These results may suggest a negative feedback mechanism on C cells by exogenous CT.

Animals↗
PubMed1989

[Production of rheumatoid factor-like substance and arthritic findings in knees of mice immunized with E. coli 0:14].

Four strains of mice (A. SW, B10. D2, C57BL/6, DBA/1J) were immunized by subcutaneous injections of heat-killed E. coli 0: 14. After single or multiple immunizations, histologic sections of knee joints and a serum rheumatoid factor-like substance (RFLS) at different time intervals were studied. Immunized A. SW. mice developed hyperplasia of synovial lining cells (25 out of 49 knees) and pannus (9 out of 49 knees) which was significantly higher rate than control. A serum rheumatoid factor-like substance (RFLS) was detected in B10. D2 and C57BL/6 mice by using RAHA test and enzyme-linked immunosorbent assay. Serum IgM-RFLS was positive in all B10. D2 mice (11 of 11 mice) immunized for 24 weeks. The incidence of serum IgM-RFLS positive mice in C57BL/6 immunized for 40 weeks (3 of 4 mice) was significantly higher than in control (p less than 0.05). Production of serum RFLS was not recognized in a single-immunized group of B10. D2 mice on statistical evaluation. These findings provided evidence that arthritis was developed in multiple-immunized groups of A. SW mice and RFLS was produced in multiple-immunized groups of B10. D2 and C57BL/6 mice. In addition, these findings suggested that multiple-immunization was necessary for the production of RFLS.

Animals↗
PubMed1989

A newly modified isolation method of single muscle fibers--especially useful in histological, histochemical and electron microscopic studies on branched fibers.

The nitric acid muscle fiber digestion method has generally been used to determine total numbers of muscle fibers and branched fibers. However, it is not suitable for further studies because nitric acid causes protein denaturation known as the xanthoproteic reaction which make it difficult to examine the fiber types and morphology of muscle fibers. Therefore, we attempted to modify this method to preserve the morphology of muscle fibers as much as possible. Our modifications were as follows: (1) samples were immersed in ion exchanged water before nitroc acid treatment; (2) mammalian relaxing solution was used as the post- incubation solution; (3) the temperature of nitric acid was maintained at 4 degrees C; and (4) the nitric acid concentration was reduced to 10% from 15%. The samples obtained by this method were stained with phosphotungstic acid-hematoxylin and their striations were examined by a differential interference contrast method using light microscopy. The cell organella i.e. actin filaments, myosin filaments, T-tubules and mitochondria, were also examined electron microscopy. Actin and myosin filaments in these samples were also stained immunohistochemically to clarify the preservation of antigenicity. As a result, this modified method made it possible to examine actin and myosin filaments of a single muscle fiber light-microscopically and immunohistochemically and also to examine cell organella of a single muscle by electron microscopy. These results indicate that our method is useful for studies on branched muscle fibers such as stereological analysis and innervation of a single branched muscle fiber, in addition to obtaining muscle fiber numbers.

Actins↗
PubMed1988

SF2446, new benzo[a]naphthacene quinone antibiotics. I. Taxonomy and fermentation of the producing strain, isolation and characterization of antibiotics.

New antibiotics SF2446A1, A2, A3, B1 and B2 have been isolated from the culture of Streptomyces sp. SF2446 and antibiotic SF2446B3 has been obtained by methanolysis of SF2446B1 or B2. SF2446A1, A2 and B1 showed strong inhibitory activities against mycoplasmas and Gram-positive bacteria. Empirical molecular formulae of antibiotics SF2446-A1, A2, A3, B1, B2 and B3 were determined to be C34H35NO15, C26H21NO11, C34H35NO14, C34H35NO14 and C26H21NO10, respectively.

Aminoglycosides↗
PubMed1988

SF2446, new benzo[a]naphthacene quinone antibiotics. II. The structural elucidation.

Structures of new antibiotics SF2446A1, A2, A3, B1, B2 and B3 have been deduced by means of spectral analyses and chemical studies. The structure of SF2446A1 which is a main product of fermentation and has the strongest antimicrobial activity, has been proposed to be 11-(2,4-di-O-methyl-beta-L-rhamnopyranosyl)amino-5,6,6a,14a-tetrah ydro- 1,6,8,14a-tetrahydroxy-6a-methoxy-2-methoxycarbonyl-3-methyl- benzo[a]naphthacene-7,9,12,14-tetra-one. All of antibiotics have a novel benzo[a]naphthacene quinone skeleton and SF2446A1, A2, B1 and B2 have an N-glycosidic linkage with 2,4-di-O-methyl-L-rhamnose.

Aminoglycosides↗
PubMed1987

[Studies on the immunoregulation of anti-thyroglobulin antibody synthesis by lymphocytes in the patients with Hashimoto's disease and Graves' disease].

Anti-thyroglobulin antibody (aTg) synthesis by the lymphocytes in the peripheral blood and the thyroid gland were studied in patients with Hashimoto's disease (HD) or Graves' disease (GD), all in euthyroid states, to clarify the mechanism of autoantibody synthesis. The ability of the lymphocytes to synthesize aTg was analyzed in the culture system of lymphocytes incubated in a concentration of 1 X 10(6) cells/ml for 7 days at 37 degrees C in 5% CO2-95% air. The B cells alone were also cultured in the absence of T cells or PWM to estimate their abilities on spontaneous aTg synthesis. The regulatory functions of T cells on aTg synthesis by B cells were investigated in cross-combination cultures of B cells and an equal number of T cells. The concentration of aTg and total IgG in cultured medium were measured by sensitive enzyme immunoassay developed by us, and the capacity on aTg synthesis was expressed as aTg/IgG ratio (aTg%). The surface markers of lymphocytes in the peripheral blood and the thyroid gland were determined by flowcytometry using mouse monoclonal antibodies (CD3, CD4, CD8, OKIa1, CD20 and Leu7). These results were obtained as follows: 1) All the lymphocytes from the peripheral blood, thyroid gland and bone marrow of HD patients synthesized much more aTg (3.1 +/- 1.6, 2.2 +/- 0.9, 1.5 +/- 0.5%, respectively) than those from normal peripheral blood lymphocytes (1.0 +/- 0.9%). This hyper-function of aTg synthesis by the lymphocytes in HD patients was caused by the presence of activated B cells and the predominance of helper T cells. 2) Both the lymphocytes from the peripheral blood and the thyroid gland in GD patients synthesized the same level of aTg (0.7 +/- 0.7%) as in normal subjects. However, the lymphocytes from bone marrow and lymph nodes, which were indicated by Benner et al. to play a main role in antibody synthesis after immunization with antigen, were involved in aTg synthesis (1.8 +/- 1.2, 5.4 +/- 1.1%, respectively). 3) There was no correlation between aTg synthesis and CD4+/CD8+ ratio of the peripheral blood lymphocytes in AITD patients. These results suggest that aTg synthesis in HD patients is an expression of abnormal immune reaction due to the presence of aTg specific activated B cells and dysfunction of regulatory T cells, and that aTg production by the lymphocytes from the bone marrow and lymph nodes in GD patients is resulted from a normal immune response to the high level of thyroglobulin in the blood.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoantibodies↗