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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 1,243 records · Page 69Linked to original sources
PubMed1986

Cleavage of DNA by model complexes of cytochrome P-450.

Thiolate-hemin complexes as chemical models for cytochrome P-450 have been shown to cause cleavage of DNA. The cleavage of DNA to open-circular and linear forms depended on the structure of thiol ligand and the thiol ligand:hemin ratio at pH 7.8. Complete cleavage of DNA was observed by complexes containing thioglycolate ethylester and mercaptoethanol at 400-600 moles excess of thiol ligand to hemin, those containing cysteine, cysteine methylester and cysteine ethylester at 50-200 moles excess, and those containing mercaptopropionylglycine, glutathione, glutathione dimethylester, penta- and nonapeptides at 5-100 moles excess. Inhibition experiments suggested the involvement of active oxygen species in the cleavage of DNA.

Cytochrome P-450 Enzyme System↗
PubMed1986

[A case of giant cell glioblastoma].

The pathological entity of intracranial giant cell tumor remains controversial, which has been considered a glioma (giant cell glioblastoma) by some and a sarcoma (monstrocellular sarcoma) by others. The authors present a case in which CT scan shows a wedge-shaped high density area at the left parietal lobe. This tumor expands explosively only a month on serial CT scan. The microscopic speciemen demonstrates the bizarre irregular giant cells with large vesicular nuclei, and glial proliferation and abundant reticulin fibers. Then we reviewed and discussed with emphasis on the historical aspect of giant cell tumor and also radiologic, therapeutic problem.

Brain Neoplasms↗
PubMed1986

[Management of full term breech presentation--criteria for safe vaginal delivery (without extraction of the breech head)].

It is very important to appraise cephalo-pelvic disproportion (CPD), and to predict the necessity of extraction of the after-coming head on full-term breech presentation. Subjects were 47 cases of full-term breech presentation which delivered at our hospital during the 5-year period from 1979 to 1983. They were divided into the following groups: group A Assisted breech delivery. group B Extraction of after-coming head. group C Abdominal delivery for secondary inertia. In each case we subtracted the fetal occipitofrontal diameter from the individual pelvic diameter and compared the results for groups A and B. There were significant differences between groups A and B in the mean values (cm) for the following: True antero-posterior diameter of the wide; 1.341 +/- 1.009 and 0.380 +/- 0.379 (p less than 0.001). Antero-posterior diameter of the Fukushima's wide; 2.005 +/- 0.906 and 0.860 +/- 0.502 (p less than 0.01). Posterior-sagittal diameter of the wide; -5.300 +/- 1.026 and -6.020 +/- 0.340 (p less than 0.05). Antero-posterior diameter of the midpelvis; 1.414 +/- 1.035 and -0.110 +/- 0.718 Posterior-sagittal diameter of the midpelvis (Caldwell-Moloy); -5.759 +/- 1.041 and -6.560 +/- 0.573 (p less than 0.05). Posteriol-sagittal diameter of the midpelvis (Thoms): -6.173 +/- 1.083 and -7.430 +/- 0.750 (p less than 0.01). Furthermore, there were also significant differences between groups A and C: The margins of safety values for each pelvic diameter (cm) were as follows: Antero-posterior diameter of the midpelvis; (13.1): Posterior-sagittal diameter of the midpelvis (Thoms); (5.5): Inter-spinous diameter; (11.0): Inter-tuberous diameter; (11.3).(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1986

[Prognostic values of the doubling time of serum carcinoembryonic antigen and calcitonin levels in medullary thyroid carcinoma].

Fifteen patients operated on for medullary thyroid carcinoma with elevated postoperative serum calcitonin (CT) levels underwent serial measurements of serum CT and carcinoembryonic antigen (CEA) levels. Both CT and CEA levels showed an exponential increase in 12 patients and a slight decrease in three. CEA levels manifested less fluctuation than CT levels. The doubling time of these tumor marker levels calculated from the regression line in each patient showed a strong correlation with three-year survival, recurrence within five years, and the time interval between surgery and recurrence of the tumor, allowing quantitative prediction of the prognosis. However, the doubling time of CEA was longer than that of CT in most patients.

Adult↗
PubMed1985

Origin of human T-lymphotrophic virus I-positive T cell lines in adult T cell leukemia. Analysis of T cell receptor gene rearrangement.

Using the clone-specific rearrangement of the T cell receptor gene as the genetic marker of the clonotype, we analyzed the clonal origin of the interleukin 2 (IL-2)-dependent human T-lymphotrophic virus I (HTLV-I)-positive T cell lines established from various adult T cell leukemia (ATL) patients. From a patient with chronic ATL, whose leukemic cells proliferated in vitro in response to IL-2, we repeatedly established leukemic T cell clones having the same rearrangement profile of the T beta chain gene as the leukemic cells. By contrast, established cell lines from acute ATL patients had different beta chain gene rearrangements from those of the leukemic cells. These HTLV-I+ T cell lines might not be the direct progeny of the leukemic cells, but that of T cells infected either in vivo or in vitro. These IL-2-reactive nonleukemic T cells might have been selected in vitro, because their leukemic cells failed to respond to IL-2, despite the expression of IL-2 receptor. The analysis of the T cell receptor gene rearrangement may give a new approach for the elucidation of the mechanism of leukemogenesis and the origin of the HTLV-I+ T cell lines in ATL.

Acute Disease↗
PubMed1985

Chemiluminescent enzyme immunoassay using beta-D-galactosidase as the label and the bis(2,4,6-trichlorophenyl)oxalate-fluorescent dye system.

A chemiluminescent enzyme immunoassay (EIA) using beta-D-galactosidase as the enzyme label is described in this report. The activity of beta-D-galactosidase, after separation of bound and free fractions, was measured using a coupled enzyme procedure: lactose and glucose oxidase were used as the substrate and coupling enzyme, respectively. Hydrogen peroxide generated from glucose was determined by the chemiluminescence reaction using the bis(2,4,6-trichlorophenyl)oxalate-fluorescent dye system. This assay system was applied to the EIA of phenytoin using beta-D-galactosidase as the label and assay sensitivity was increased about 10 times compared with the original method. This method may also be applied to other EIAs of digitoxin, alpha-fetoprotein and thyroid-stimulating hormone.

Digitoxin↗
PubMed1985

Quantitative immunoassay for IgA class circulating immune complexes using solid phase Facb fragment of anti-C3.

A quantitative assay of IgA class circulating immune complexes (IgA-CIC) by a solid phase anti-C3 enzyme immunoassay (anti-C3 EIA) is described. A stable and reproducible standard for determination of IgA-CIC was prepared successfully by chemical binding of complement C3 to human serum IgA. Two of 27 sera from patients with systemic lupus erythematosus (SLE), however, contained high concentrations of IgA class anti-F(ab')2 antibodies that caused false positive results when the F(ab')2 of anti-C3 was used for EIA. Solid phase Facb of anti-C3 was found to eliminate the false positive results caused by IgA class anti-F(ab')2 and IgA class rheumatoid factor. Good reproducibility and recovery were observed with this Facb anti-C3 EIA using the IgA-C3, a stable standard material, and so this method should be useful clinically in elucidating the role of IgA-CIC.

Adult↗
PubMed1985

An enzyme-linked immunosorbent assay for thyroxine in dried blood spotted on filter paper.

We have developed a rapid and sensitive enzyme-linked immunosorbent assay (ELISA) for thyroxine (T4) in dried blood samples spotted on filter paper. The assay is carried out on microtiter plates without extraction or centrifugation steps. The detection limit of the assay is 5 pg/disc/well, equivalent to 1.25 micrograms/1 of whole blood or 2.5 micrograms/1 of serum. Intra- and inter-assay coefficients of variation for various T4 concentrations are 2.4-9.0% and 5.9-17.5% respectively. Correlation between the proposed ELISA method and the RIA is good (r = 0.900, n = 62, y(RIA) = 0.99x(ELISA) + 9.90). The ELISA method is useful for mass-screening of neonatal congenital hypothyroidism using dried blood samples on filter paper, is very simple and one person can assay more than 300 samples per day.

Enzyme-Linked Immunosorbent Assay↗