Biomedical subjects

Mitsuhiro Matsumoto

Publications and source records attributed to Mitsuhiro Matsumoto.

25 records · Page 2Linked to original sources

PubMed2003

Analysis of entrance surface dose in general radiographies using body mass index classification.

Dose audit is an important topic in radiology and variations in dose attributable to sex have not been fully investigated. The primary purpose of our study was to determine the entrance surface dose (ESD) for men and women, from which we established an easy estimation equation for ESD, using the body mass index (BMI) as a variable. From April 2000 to March 2002, 15424 patients (8586 men, 6838 women; mean age, 58 years old; age range, 20 to 90 years old) were recruited in this study. Estimated equation of ESD was obtained from the dispersion data of BMI and ESD. Welch's t-test was used as the test of significance. P values evaluated levels of significance at 5%. Analysis for correlation coefficients was used for Peason's correlation coefficient test. And, we also performed a simple regression analysis. The results of the simple regression equation with BMI as variable (y: ESD [mGy], x: BMI [kg/m(2)), and the median values of ESD were as follows: for chest PA, men, 0.22, y = 0.0145 x - 0.0876, women, 0.20, y = 0.0126 x - 0.0704; for abdomen AP, men, 2.12, y = 0.2707 x - 3.7206, women, 1.65, y = 0.2561 x - 3.7989; for pelvis AP, men, 1.87, y = 0.0517 x + 0.8753, women, 1.77, y = 0.0674 x + 0.4775; for lumbar spine AP, men, 3.08, y = 0.3462 x - 4.1416, women, 2.66, y = 0.2525 x - 2.8131; and for lumbar spine lateral, men, 9.31, y = 0.6012 x - 3.7216, women, 7.42, y = 0.3147 x + 0.3384. The results of ESD had a significant difference between sexes (P < 0.05). Chest PA, abdomen AP, lumbar spine AP, and lumbar spine lateral each had a good correlation between ESD and BMI (r: 0.4 to 0.8). We successfully obtained the estimation equation using BMI as variable.

Body Mass Index↗

PubMed2002

Proteolytic cleavage of the CD44 adhesion molecule in multiple human tumors.

Cell surface adhesion molecules are crucial for the development and/or pathogenesis of various diseases including cancer. CD44 has received much interest as a major adhesion molecule that is involved in tumor progression. We have previously demonstrated that the ectodomain of CD44 undergoes proteolytic cleavage by membrane-associated metalloproteases in various tumor cell lines. The remaining membrane-bound CD44 cleavage product can be detected using antibodies against the cytoplasmic domain of CD44 (anti-CD44cyto antibody). However, the cleavage of CD44 in primary human tumors has not been investigated. Using Western blots with anti-CD44cyto antibody to assay human tumor tissues, we show that the CD44 cleavage product can be detected in 58% (42 of 72) of gliomas but not in normal brain. Enhanced CD44 cleavage was also found in 67% (28 of 42) of breast carcinomas, 45% (5 of 11) of non-small cell lung carcinomas, 90% (9 of 10) of colon carcinomas, and 25% (3 of 12) of ovarian carcinomas. Tumors expressing a CD44 splice variant showed a significantly higher incidence of enhanced CD44 cleavage. The wide prevalence of CD44 cleavage suggests that it plays an important role in the pathogenesis of human tumors.

Brain↗

PubMed2002

Structure-activity relationships of 6-nitroquinazolines: dual-acting compounds with inhibitory activities toward both TNF-alpha production and T cell proliferation.

We synthesized various 6-nitroquinazolines by modifying the structure of compound 1 and evaluated their inhibitory activities toward both TNF-alpha production and T cell proliferation responses. The presence of the unsubstituted piperazine ring at the C(7)-position was required for both inhibitory activities. In this series of compounds, 5d and 5f, containing the 4-fluorophenyl and 3,4-difluorophenyl moiety, respectively, at the C(4)-position, showed the suppressing effects toward both responses with low cell growth inhibition. Furthermore, the oral administration of these compounds mentioned above at doses of 30 and 100 mg/kg also resulted in significant inhibition of TNF-alpha production induced by LPS in vivo.

Animals↗

PubMed2002

[Evaluation of compensation filter in I.I.-DR gastrointestinal examination using image pick-up tube].

We have especially the thing which experiences daily and which digital value does saturate by the difference of patient, and the air content of internal organs, at the time of I.I.-DR gastrointestinal examination. In order to compensate digital value of those parts, the compensation filter by the remote operation formula was examined. The quality of the material of the created filter determined thickness and form from change of digital value when changing thickness, and a dose using aluminum. The image which carried out saturate as a result of analyzing this 500 images decreased to 15% to 3%. Moreover, the total skin dose decreased on the same photography conditions, and was almost equivalent in the time of phototimer use. The part not conventionally materialized as an image for saturation has been improved by using a compensation filter for gastrointestinal examination, and it was enabled to obtain a useful picture clinically.

Digestive System↗

PubMed2001

Cooperation of HECT-domain ubiquitin ligase hHYD and DNA topoisomerase II-binding protein for DNA damage response.

Ubiquitin ligases define the substrate specificity of protein ubiquitination and subsequent proteosomal degradation. The catalytic sequence was first characterized in the C terminus of E6-associated protein (E6AP) and referred to as the HECT (homologous to E6AP C terminus) domain. The human homologue of the regulator of cell proliferation hyperplastic discs in Drosophila, designated hHYD, is a HECT-domain ubiquitin ligase. Here we show that hHYD provides a ubiquitin system for a cellular response to DNA damage. A yeast two-hybrid screen showed that DNA topoisomerase IIbeta-binding protein 1 (TopBP1) interacted with hHYD. Endogenous hHYD bound the BRCA1 C-terminus domains of TopBP1 that are highlighted in DNA damage checkpoint proteins and cell cycle regulators. Using an in vitro reconstitution, specific E2 (ubiquitin-conjugating) enzymes (human UbcH4, UbcH5B, and UbcH5C) transferred ubiquitin molecules to hHYD, leading to the ubiquitination of TopBP1. TopBP1 was usually ubiquitinated and degraded by the proteosome, whereas X-irradiation diminished the ubiquitination of TopBP1 probably via the phosphorylation, resulting in the stable colocalization of up-regulated TopBP1 with gamma-H2AX nuclear foci in DNA breaks. These results demonstrated that hHYD coordinated TopBP1 in the DNA damage response.

Animals↗

PubMedDate not supplied

Quantitative analysis for computed tomography findings of various diffuse lung diseases using volume histogram analysis.

OBJECTIVES: : The aim of this study was to achieve the quantitative analysis of the characteristic computed tomography (CT) findings and course of interstitial pneumonia using the volume histogram method. METHODS: : Contrast (CNT), variance (VAR), and entropy (EPY) values from whole-lung volume data were compared between normal lungs and 5 diseases that have characteristic CT findings. Thirteen cases with nonspecific interstitial pneumonia (NSIP) were evaluated before and after treatment. RESULTS: : In cases with thickening of the bronchovascular bundles and interlobular thickening, ground-glass attenuation, airspace consolidation, and honeycombing, the values of VAR and EPY were greater than those in the normal cases (P < 0.05). In the cases with NSIP, the CNT value after treatment was significantly greater and the values of VAR and EPY after treatment were significantly lower than those before treatment (P < 0.05). CONCLUSIONS: : Volume histogram analysis is a promising method for the evaluation of diffuse lung diseases and the effectiveness of treatment.

Adolescent↗

PubMedDate not supplied

Real-time estimation system for mean glandular dose in mammography.

PURPOSE: The purpose of this study was to construct a system that calculates mean glandular dose (MGD) in mammography in real-time on the RIS network. MATERIALS AND METHODS: Measurement of the half-value layer (HVL) and exposure dose were measured according to the Japanese mammographic quality control manual. A parallel plate chamber (10X5-6M; soft X-rays only) was used for measurement. Exposure dose was measured from 26 to 32 kV. RESULTS: Effective energy (Eeff [keV]) could be determined from tube voltage (V [kV] ) using the measure of the HVL according to the following equations: for the Mo/Mo combination, Eeff = 0.1325V + 11.80; for the Mo/Rh combination, Eeff = 0.1435V + 12.20; for the Rh/Rh combination, Eeff = 0.1724V + 11.29. Exposure output (XmAs [mR/mAs]), which can be determined from dosimetry per 1 mAs, becomes the following equation if effective energy is expressed as a variable: for the Mo/Mo combination, XmAs = 2.1329 Eeff2 - 57.784 Eeff + 392.71; for the Mo/Rh combination, XmAs = 1.1919 Eeff2 - 31.924 Eeff + 212.23; and for the Rh/Rh combination, XmAs = 2.6929 Eeff2 - 82.831 Eeff + 643.54. The MGD conversion factor (DgN [mGy/mR]) can be determined from effective energy using the ACR protocol according to the following equation: for the Mo/Mo combination, DgN = (0.3962 Eeff- 4.3178) 10(-3); for the Mo/Rh combination, DgN = (0.3495 Eeff - 3.5479) x 10(-3); and for the Rh/Rh combination, DgN = (0.4498 Eeff - 5.0448) x 10(-3). However, in these cases, compression breast thickness (CBT) was 4.2 cm, and the ratio of adipose and glandular tissue was 50/50. CONCLUSION: MGD can be determined using mAs obtained from mammography, exposure output (XmAs), MGD conversion factor (DgN), and source-skin distance compensation factor (SSDcf) according to the following equation: MGD [mGy] = mAs x XmAs [mR/mAs] x DgN [mGy/mR] x SSDcf where SSDcf = (64/(64 - CBT [cm]))2.

Breast↗