Biomedical subjects

M Azuma

Publications and source records attributed to M Azuma.

459 records · Page 26Linked to original sources

PubMed1966

Application of cell fractionation techniques in the study of cells infected with polyoma virus and Newcastle disease virus.

Fisher, Harold W. (University of Rhode Island, Kingston), Hidemi Matsumiya, and Masanobu Azuma. Application of cell fractionation techniques in the study of cells infected with polyoma virus and Newcastle disease virus. J. Bacteriol. 91:1645-1651. 1966.-Techniques which permitted rigorous separation of nuclei and cytoplasm were applied to the study of the formation of Newcastle disease virus (NDV) in an established line of Chinese hamster cells and of polyoma virus (PYV) in mouse embryo fibroblasts. The results obtained for hemagglutinin and plaque-forming titers during virus growth were in agreement with those obtained by others, using different techniques. These indicated that NDV matures in the cytoplasm, and PYV in the nucleus, of host cells.

Animals↗

PubMedDate not supplied

Expression of calpain small subunit 2 in mammalian tissues.

PURPOSE: The purpose of the current experiments was to more closely define the distribution and the function of calpain small subunit 2 (css2). Css2 is a newly discovered regulatory protein for the calcium activated proteases, mu- and m-calpains. METHODS: Tissues from rat, monkey, and man of various ages were used to determine expression patterns of css2 by relative quantitative RT-PCR using 18S rRNA as an endogenous standard. Recombinant css2 and the 80 kDa catalytic subunit of m-calpain (80 kDa/css2) were co-expressed in Escherichia coli. Casein zymography was used to measure the enzymatic activity of 80 kDa/css2 proteins. Lens alpha-crystallin and beta B1-crystallin were used as substrates to determine proteolysis by 80 kDa/css2. Computer-based homology modeling was used to predict interactions between the traditional small subunit (css1) or css2 with the 80 kDa catalytic subunit. RESULTS: Css2 appears to be a functional equivalent of css1 in vitro in that the calcium-dependent proteolytic activity of 80 kDa/css2 was similar to recombinant m-calpain (80 kDa/css1). In rat and human lens, css2 transcripts increased with age, whereas css1 transcripts decreased with age. Human beta B1-crystallin and rat alpha A-crystallin were cleaved similarly by 80 kDa/css2 and 80 kDa/css1. Interestingly, alpha A-insert crystallin was not hydrolyzed when css2 was substituted for css1 in the calpain dimer, suggesting that css2 may perform different functions from css1 in terms of proteolysis of lens crystallins during maturational growth of the lens. Css2 may also assist in the proper folding of the 80 kDa subunit and regulate protease activity in the absence of calcium. CONCLUSIONS: The wide distribution of css2 transcripts in rat and monkey suggested that css2 is a second, widely distributed (rather than tissue-specific) calpain small subunit, in addition to the long-recognized css1. Further studies at the protein level will indicate if css2 has unique functions apart from css1.

Adolescent↗

PubMedDate not supplied

Development of a new cellulose triacetate membrane with a microgradient porous structure for hemodialysis.

Dialytic performance and biocompatibility of a newly developed cellulose triacetate (CTA) membrane with a microgradient porous structure, produced without using polyvinylpyrrolidone (PVP) and liquid paraffin, were compared with those of a conventional polysulfone (PS) membrane dialyzer. In vitro and clinical results demonstrated no significant difference in the dialytic performance and biocompatibility of the two dialyzers, but the CTA dialyzer lost less albumin during dialysis than the PS. These results suggest that a CTA membrane dialyzer with a porous microgradient structure attained comparable performance and biocompatibility to PS, and the risk of albumin loss was suppressed by the new CTA membrane.

Cellulose↗

PubMedDate not supplied

Sensitive measurement of serum abnormal prothrombin (PIVKA-II) as a marker of hepatocellular carcinoma.

BACKGROUND/AIMS: The usefulness of abnormal prothrombin (PIVKA-II) for diagnosis of small HCC has been limited by its low sensitivity, despite a high specificity. METHODOLOGY: The serum concentration of PIVKA-II was determined by using a new sensitive enzyme immunoassay (EIA) kit in patients with hepatocellular carcinoma (HCC), liver cirrhosis (LC), or chronic hepatitis (CH) and normal controls (NC). alpha-Fetoprotein (AFP) was simultaneously determined in same patients. RESULTS: This kit has made it possible to detect low concentrations of PIVKA-II in the NC. The serum PIVKA-II concentration (mean +/- SE) was 15.7 +/- 1.1 mAu/ml, 16.1 +/- 2.0 mAu/ml, 26.3 +/- 7.2 mAu/ml and 5420.3 +/- 3960.0 mAu/ml in NC, CH, LC and HCC, respectively. Among 106 patients with HCC, 74 patients (69.8%) were positive for PIVKA-II (> or = 40 mAu/ml), while only 9 patients out of 68 patients with LC were positive (13.2%) and only 2 out of 90 patients with CH were positive (2.2%). No significant correlation was observed between AFP and PIVKA-II levels. With combined assay of AFP and PIVKA-II, the positive rate for HCC was increased to 78.3%. Among 14 patients with HCC < 20 mm in diameter. 7 were positive for PIVKA-II, and 6 out of 10 patients with HCC between 20 and 30 mm in diameter were positive for PIVKA-II. There was a correlation between tumor size and the PIVKA-II level. CONCLUSIONS: Determination of PIVKA-II by this new EIA kit could be useful for the diagnosis of HCC, especially combined with determination of AFP.

Biomarkers↗

PubMedDate not supplied

Evaluation of compressed lung CT image quality using quantitative analysis.

The goals of this study were (1) to evaluate the quality of compressed lung CT images obtained using high resolution CT (HRCT: 2 mm slice thickness) for degree of compression and conventional CT (10 mm slice thickness) images by using physical and subjective evaluations, and (2) to analyze the distortion of density distribution on lung CT images using histogram analysis for each compression ratio. The coding method was performed according to the Joint Photographic Experts Group (JPEG). We physically evaluated the quality of compressed lung CT images using the peak signal-to-noise ratio (PSNR) as given by the square root of the ratio of the peak value of the gray level squared to the mean square error (dB) and subjectively evaluated the CT images using the mean opinion score (MOS). The acceptable compression ratio for diagnosis was about 1:6 to 1:7 for conventional CT images and about 1:4 to 1:5 for HRCT images as determined by MOS. The PSNR corresponding to acceptable compression ratios was about 50 dB. The difference in density distribution between HRCT and conventional CT was statistically significant (Friedman test: p<0.02) in histogram analysis. Results suggested that, in comparison with conventional CT, a high compression ratio was not suitable for HRCT.

Algorithms↗

PubMedDate not supplied

Predictive factors for efficacy of interferon therapy in chronic hepatitis type C.

BACKGROUND/AIMS: It has recently become possible to quantify HCV-RNA in serum and to analyze the HCV-RNA genotype. In this study, we investigated the relationship among the response to interferon therapy, the HCV-RNA concentration, genotype and histological findings of the liver. PATIENTS AND METHODS: Sixty-three patients with chronic hepatitis type C received interferon alfa therapy for 24 weeks. The HCV-RNA concentration in serum was measured semiquantitatively with reverse transcript semi-nested polymerase chain reaction and classified as negative to +3. HCV-RNA genotype was analyzed using a mixture of four type specific primers. RESULTS: HCV-RNA concentration was significantly higher in patients with genotype II and CAH2B than genotype III, CPH and CAH2A (p < 0.05). At 24 weeks after the end of interferon therapy, HCV-RNA in serum disappeared in 24 of 63 patients (38%). Strong resistance to the therapy was noted in patients with both genotype II and a high concentration of HCV-RNA in serum (the efficacy was only 7%). Therapy efficacy decreased with the severity of liver histological findings, reaching only 20% in those with CAH2B. CONCLUSION: Both the concentration and genotype of HCV-RNA seem to be important factors in determining the efficacy of interferon therapy.

Adult↗

PubMedDate not supplied

Expression of ductal Fas antigen in sialoadenitis of Sjögren's syndrome.

OBJECTIVE: The expression of Fas antigen on ductal epithelial cells of sialoadenitis was examined in patients with Sjögren's syndrome (SS) and in normal subjects. METHODS: Minor salivary glands from the SS patients were examined by an immunohistochemical method using a new monoclonal antibody to the Fas antigen. RESULTS: In two patients with severe sialoadenitis, Fas was strongly expressed on the ductal epithelial cells. By contrast, the Fas antigen was not seen in the minor salivary glands of normal subjects nor in those with mild sialoadenitis. CONCLUSION: This finding suggests that the Fas antigen may play a role in the pathogenesis of sialoadenitis in SS by providing a specific target for cytotoxic T cells expressing the Fas ligand.

Adolescent↗

PubMedDate not supplied

Glandular and extraglandular expression of the Fas-Fas ligand and apoptosis in patients with Sjögren's syndrome.

OBJECTIVE: To evaluate the role of Fas-Fas ligand system-mediated apoptosis in the sialoadenitis and interstitial nephritis of Sjögren's syndrome. METHODS: The expression of Fas antigen and Fas ligand in sialoadenitis and interstitial nephritis was examined by immunoperoxidase staining and the reverse transcriptase-polymerase reaction (RT-PCR) in patients with Sjögren's syndrome and in normal subjects. The appearance of DNA strand breaks during apoptosis was detected in the tissue by DNA nick end labeling methods. RESULTS: In patients with severe sialoadenitis, Fas antigen was strongly expressed on the ductal epithelial cells. In contrast, Fas antigen was not seen in the minor salivary glands of normal subjects nor in patients with mild sialoadenitis. In patients with massive mononuclear cell infiltration, some of the infiltrating cells showed the Fas ligand. In patients with interstitial nephritis associated with Sjögren's syndrome, Fas was expressed on the tubular epithelial cells, while such expression was not observed in control subjects without interstitial nephritis. In the patients with interstitial nephritis, some of the infiltrating cells showed the Fas ligand. Apoptotic changes were observed in the ductal epithelial cells, tubular epithelial cells and some infiltrating cells by DNA nick end labeling methods. mRNA for the Fas antigen and Fas ligand was found to be expressed in the labial salivary glands from all SS patients by RT-PCR. CONCLUSION: The findings of this study suggest that the Fas-Fas ligand system may play a role in the pathogenesis of the sialoadenitis and interstitial nephritis of Sjögren's syndrome.

Adolescent↗

PubMedDate not supplied

Oxygen administration during hepatic DSA.

The research presented in this article examined the role of oxygen in preventing diaphragmatic motion artifacts in delayed-phase hepatic digital subtraction angiography (DSA). The results demonstrate that administering oxygen to patients before the examination substantially reduces artifacts due to motion.

Adult↗