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Biomedical subjects

S Mizuno

Publications and source records attributed to S Mizuno.

At least 235 records · Page 13Linked to original sources
PubMed1996

Analysis of 55 transplantations from unrelated volunteer donors facilitated by Tokai Marrow Donor Bank.

In October, 1989, the Tokai Marrow Donor Bank (TMDB) was established through the cooperation of patients' families, the branches of blood centers of Japanese Red Cross and the hematologists' group in Tokai Area (Aichi, Shizuoka, Gifu and Mie Prefectùres) in Japan to facilitate the procurement of suitable marrow from unrelated volunteer donors for patients lacking related donors. The number of human leukocyte antigen (HLA)-A, B typed donors totaled 3,083 and the number of patients registered for donor search totaled 1,415 by June 1992, when the activities of TMDB were transferred to the newly created Japan Marrow Donor Program (JMDP), and 55 transplanations from unrelated donors facilitated by TMDD were performed.

Adolescent↗
PubMed1996

Cancer mortality in Minamata disease patients exposed to methylmercury through fish diet.

We report here a historical cohort study on cancer mortality among Minamata disease (MD) patients (n = 1,351) in Kagoshima and Kumamoto Prefectures of Japan. Taking into account their living area, sex, age and fish eating habits, the residents (n = 5,667; 40 years of age or over at 1966) living in coastal areas of Kagoshima, who consumed fish daily, were selected as a reference group from the six-prefecture cohort study conducted by Hirayama et al. The observation periods of the MD patients and of the reference group were from 1973 to 1984 and from 1970 to 1981, respectively. Survival analysis using the Poisson regression model was applied for comparison of mortality between the MD patients and the reference group. No excess of relative risk (RR) adjusted for attained age, sex and follow-up period was observed for mortality from all causes, all cancers, and non-cancers combined. Analysis of site-specific cancers showed a statistically significant decrease in mortality from stomach cancer among MD patients (RR, 0.49; 95% confidence interval, 0.26-0.94). In addition, a statistically significant eight-fold excess risk, based on 5 observed deaths, was noted for mortality from leukemia (RR, 8.35; 95 % confidence interval 1.61-43.3). It is, however, unlikely for these observed risks to be derived from methylmercury exposure only. Further studies are needed to understand the mechanisms involved in the observed risks among MD patients.

Adult↗
PubMed1996

Value of three-dimensional spiral CT hepatic angiography.

OBJECTIVE: The aim of this study was to compare with conventional angiography images the diagnostic utility of three-dimensional CT hepatic angiography (CTHA) images reconstructed from spiral CT images obtained during direct injection of contrast material into hepatic arteries. MATERIALS AND METHODS: Three-dimensional CTHA images were reconstructed from spiral CTHA images obtained during direct hepatic arterial contrast material injection in 22 patients. We used maximum-intensity-projection (MIP) and shaded-surface-display (SSD) techniques. We compared matched pairs of MIP CTHA images and SSD CTHA images with conventional angiograms for depiction of peripheral (segmental to subsegmental order branches) and proximal (common to proper) hepatic arteries as well as for conspicuity of the entire hepatic arterial tree in 22 patients and for conspicuity of tumors, recognition of tumor sites, and depiction of tumor-feeding arteries in 21 patients with malignant liver tumors. Our evaluations were performed in a blinded fashion by two experienced radiologists, who reached a consensus. (These radiologists also counted the number of tumors depicted by each method in the 21 patients with malignant liver tumors.) RESULTS: Depiction of peripheral and proximal hepatic arteries and conspicuity of the entire hepatic arterial tree were significantly better on conventional angiograms than on MIP CTHA images and SSD CTHA images. Conspicuity of tumors and recognition of tumor sites were significantly better on MIP CTHA images and SSD CTHA images than on conventional angiograms. Depiction of tumor-feeding arteries was significantly better on MIP CTHA images than on SSD CTHA images and conventional angiograms. For 47 malignant liver tumors, MIP CTHA images showed 40 (85%), SSD CTHA images showed 34 (72%), and conventional angiograms showed 20 (43%). CONCLUSION: MIP CTHA images showed liver tumors, tumor sites, and tumor-feeding arteries better than conventional angiograms. MIP was the preferred method for three-dimensional CTHA analysis.

Aged↗
PubMed1996

Enzymatic 2'-N-acetylation of arbekacin and antibiotic activity of its product.

Aminoglycoside antibiotics (AGs) with a free 2'-amino group were subjected to enzymatic N-acetylation using a cell free extract that contained an aminoglycoside 2'-N-acetyltransferase, AAC (2'), derived from a kasugamycin-producing strain of Streptomyces kasugaensis. TLC and antibiotic assay of the incubated reaction mixtures revealed that a modified compound retaining substantial antibiotic activity was formed from arbekacin (ABK), while modification of the other AGs resulted in the marked decrease in antibiotic activity. Structure determination following isolation from a large scale reaction mixture showed the modified ABK to be 2'-N-acetyl ABK. In addition, 2',6'-di-N-acetyl ABK was formed as a minor product. The same conversion also occurred with dibekacin (DKB) resulting in the formation of 2'-N-acetyl DKB and 2',6'-di-N-acetyl DKB. MIC determination showed antibacterial activity (1.56 approximately 3.13 micrograms/ml) of 2'-N-acetyl ABK against a variety of organisms. By contrast, 2'-N-acetyl DKB showed no substantial antibiotic activity. We believe 2'-N-acetyl ABK has the highest and broadest antibacterial activity, compared with known N-acetylated AGs.

Acetylation↗
PubMed1996

Mechanism of multiple aminoglycoside resistance of kasugamycin-producing Streptomyces kasugaensis MB273: involvement of two types of acetyltransferases in resistance to astromicin group antibiotics.

The biochemical basis for the multiple resistance to aminoglycoside antibiotics (AGs) of kasugamycin-producing Streptomyces kasugaensis MB273 was studied. The strain was resistant to a wide range of deoxystreptamine (DOS)-containing AGs as well as astromicin (ASTM) group antibiotics. These AGs strongly inhibited in vitro polyU-directed polyphenylalanine-synthesis using ribosomes from the strain, while they were acetylated and inactivated by the MB273 cell free extract supplemented with acetyl-CoA. It seemed thus likely that the acetyltransferase activity played a critical role for the multiple AG resistance. The acetylation was selective to AGs with 2'-NH2, suggesting the involvement of aminoglycoside 2'-N-acetyltransferase, AAC (2'). Interestingly, the acetylation of istamycin B (ISM-B; an ASTM group AG) resulted in the formation of two different products (1-N-acetyl ISM-B and 2"-N-acetyl ISM-B) at a similar ratio. In this context, an AAC (2') gene cloned as an ISM-B resistance gene from the strain MB273 directed the conversion of ISM-B to only 1-N-acetyl ISM-B. It seemed likely that two types of AACs [AAC(2') and a novel one] were involved in the mechanism of resistance to ASTM group AGs.

Acetylation↗
PubMed1996

Osteogenic potential of murine osteosarcoma cells: comparison of bone-specific gene expression in in vitro and in vivo conditions.

Bone tissue formation and the expression of osteoblast-specific genes were compared in vitro and in vivo for two well characterized murine clonal osteosarcoma cell lines (K7 and K8). In vitro studies were carried out under conditions that promoted extracellular matrix morphogenesis and mineralization. The K8 cells showed 8-fold greater alkaline phosphatase activity and mineral accumulation than did K7 cells during 21 days of in vitro growth. The K8 cell line showed high levels of bone sialoprotein (BSP), collagen type I (COL I), and alkaline phosphatase (APase) mRNA expression throughout its growth in vitro. In contrast, K7 cells showed an almost complete absence of BSP and COL I and very low levels of APase throughout the culture period. In vitro, both cell lines expressed very low levels of osteocalcin (OC). For in vivo studies, we used a three-dimensional culture device that permitted analysis of tissue formation by the cells after their implantation into syngeneic mice. The K8 cells consistently generated extensive mineralized woven bone after their subcutaneous implantation. The striking features distinguishing the bone formed by the implanted cells from normal recipient bone were the complete absence of osteoclasts or matrix resorption, the absence of OC protein, and very low levels of OC mRNA expression in the tissues formed by these cell lines. BSP, APase, and COL I expressions were maintained at high levels in the K8-produced tissues. In contrast to their near absence in vitro, APase, BSP, and COL I were expressed by K7 cells and increased with time in vivo. These findings demonstrate that the K7 cells in vitro are less differentiated than K8 cells, but that K7 cells in vivo undergo osteogenic maturation. Thus, expression of bone-specific genes in these osteogenic cell lines was dependent on systemic or local factors in recipient animals and was distinct for these cell lines when grown under in vitro conditions. OC protein does not appear to be needed for the mineralization of the extracellular matrix but may be needed to provide the necessary signals for the resorption and remodeling of the tissue.

Alkaline Phosphatase↗
PubMed1996

Disaster-readiness of medical facilities in Aichi Prefecture.

One month following the Great Hanshin Earthquake of January 17, 1995, we conducted a survey of 173 hospitals in Aichi Prefecture to pinpoint problems related to their actual disaster-readiness and the medical backup systems in place to deal with such disasters. This study revealed that staff at 50% of the surveyed hospitals could reach the hospital within an hour, but that communication is almost entirely dependent on phone lines, suggesting that cordless/portable/mobile phones, radio systems, Internet, communications satellites and the like should be studied in the days to come for possible use as effective communication alternatives in times of disaster. Whereas 92% of the surveyed hospitals had manuals dealing with fire outbreaks, other areas were less well represented. For example, only 36.9% of surveyed hospitals had manuals for earthquakes, 31.7% had manuals for power outages and 14.2% had manuals to deal with flooding and water disasters. New manuals must be developed incorporating the key points garnered from experience (especially Hanshin) and be ready for use immediately. It is the time for each hospital to seriously rethink the measures it should take to deal with disasters.

Communication↗
PubMed1995

The cDNA cloning and transient expression of a chicken gene encoding a 3 beta-hydroxysteroid dehydrogenase/delta 5-->4 isomerase unique to major steroidogenic tissues.

Two cDNA clones, on containing a 2.7-kb and the other a 1.6-kb insert, were obtained from a chicken adrenal gland cDNA library by screening with a partial chicken cDNA fragment generated by PCR. Primers were used that corresponded to conserved regions among several published cDNA sequences of mammalian 3 beta-hydroxysteroid dehydrogenase/delta 5-->4 isomerase (3 beta-HSD). Both clones contained the same open reading frame (ORF) encoding 377 amino acids (aa). The difference in their sizes was due to the use of different polyadenylation sites. The deduced aa sequence showed 54-57% overall identity with those of the human, macaque, bovine, mouse, rat and rainbow trout 3 beta-HSD. A 9-aa stretch (FYYISDDTP) is conserved among the chicken, mammalian and rainbow trout 3 beta-HSD, suggesting that it is essential for enzymatic activity. Northern blot hybridization demonstrated the presence of two types of mRNA, corresponding to the above two cDNA classes, in the adrenal gland, ovary and testis. Transient expression of the chicken ORF in COS-7 cells demonstrated coupled dehydrogenase and isomerase activities of 3 beta-HSD on three different substrates; pregnenolone, 17 alpha-hydroxypregnenolone and dehydroepiandrosterone. Among the Km values determined for the three substrates, that for dehydroepiandrosterone was the lowest, which was different from the case for human 3 beta-HSD.

3-Hydroxysteroid Dehydrogenases↗
PubMed1995

Production of a chimeric fibroin light-chain polypeptide in a fibroin secretion-deficient naked pupa mutant of the silkworm Bombyx mori.

The allelic Nd-s and Nd-sD mutations of the silkworm Bombyx mori are mapped to the same locus as that of the fibroin light (L)-chain gene (Fib-L). The silkworm carrying the homozygous Nd-s or Nd-sD mutation secretes less than 0.3% of the normal level of fibroin and produces a thin cocoon (naked pupa). In this study, cDNA sequences of the Nd-s and Nd-sD L-chains were compared with the cDNA and genomic sequences of the L-chain of the B. mori J-139 strain, a normal-level producer of fibroin. The two mutant cDNA sequences are almost identical except for one base change in the coding region. The N-terminal half of the L-chain encoded by exons I to III is identical between the mutants and J-139, but the rest of the molecule is completely different. The C-terminal half of the Nd-sD mutant L-chain is encoded by two exons, IV' and V', which are brought into proximity with the exon III by recombination between sequences in the third intron and in the far downstream region with concomitant loss of a region containing exons IV to VII. Sequences corresponding to exons IV' and V' are present about 10 kb downstream of the L-chain gene in the J-139 genome. Their homologous sequences have not been found in the DNA and protein databases. The chimeric L-chain molecule of about 27 kDa is present in posterior silk glands of Nd-s and Nd-sD strains without disulfide-bonding to the fibroin heavy (H-) chain, as revealed by Western blotting with the antibody specific to the C-terminal half of the mutant L-chain.

Amino Acid Sequence↗
PubMed1995

Functional expression of Fas antigen (CD95) on hematopoietic progenitor cells.

We investigated the expression of an apoptosis-associated antigen (Fas) (CD95) on hematopoietic progenitor cells in the presence or absence of interferon-gamma (IFN-gamma) and/or tumor necrosis factor-alpha (TNF-alpha). CD34+ cells freshly isolated from bone marrow did not express Fas. However, IFN-gamma and/or TNF-alpha induced the expression of both the mRNA of Fas and Fas itself in a dose-dependent fashion on the surface of CD34+ cells after 48 hours of serum-free culture. IFN-gamma and TNF-alpha had a synergistic effect on the induction of Fas, when both cytokines were added to the culture. The TNF-alpha-induced Fas expression is mediated by p55 TNF-alpha receptor. CD34+ cells cultured in medium alone or with stem cell factor (SCF) showed some slight expression of Fas. When anti-Fas antibody (IgM) was added to CD34+ cells after the induction of Fas expression, CD34+ cells underwent apoptosis, as shown by a decrease in the number of viable cells, morphologic changes, the induction of DNA fragmentation, and a decrease in the number of colony-forming cells (CFC) including colony-forming unit granulocytes/macrophages (CFU-GM) and burst-forming unit erythroids (BFU-E). These observations indicate that IFN-gamma and/or TNF-alpha, well known as negative hematopoietic regulators, induce functional Fas on hematopoietic progenitor cells. The suppression of hematopoiesis by negative hematopoietic regulators may be mediated in part by Fas induction.

Antigens, Surface↗
PubMed1995

A microplate assay for quantitation of anchorage-independent growth of transformed cells.

We developed a 96-well microplate assay to quantitate anchorage-independent growth of transformed cells. Wells of tissue culture microtiter plates are coated with poly(2-hydroxyethyl methacrylate) (poly-(HEMA)) to prevent cell attachment, and cells suspended in liquid media are seeded into the treated plates. Cell growth is assessed by tetrazolium dye reduction or by counting [3H]thymidine incorporation into DNA. There appeared to be a close correlation between growth in poly(HEMA)-coated plates and colony formation in soft agar, i.e., fibroblasts transformed by various oncogene proliferated in the coated plates, whereas their normal counterparts did not. Transformed cells on the nonadhesive surface were round and formed multicellular spheroids which resembled colonies in soft agar. Cells carrying either temperature-sensitive v-src or inducible v-Ki-ras oncogene proliferated on poly(HEMA)-coated plates only when they displayed transformed phenotype. This method is simple, quick, quantitative, and economical and in many cases might be more practical than conventional soft agar colony formation assay for measurement of anchorage-independent growth.

3T3 Cells↗