PubMed Health⌕ Search

Biomedical subjects

H Sagawa

Publications and source records attributed to H Sagawa.

At least 19 recordsLinked to original sources
PubMed2004

Observation of B(+)-->pppi+, B0-->ppK0, and B(+)-->ppK(*+).

We report the first observation of a b-->u type charmless baryonic B decay, B+-->pppi(+), as well as b-->s type B0-->ppK0 and B+-->ppK(*+) decays. The analysis is based on a 78 fb(-1) data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. We find B(B+-->pppi(+))=(3.06(+0.73)(-0.62)+/-0.37)x10(-6), B(B0-->ppK0)=(1.88(+0.77)(-0.60)+/-0.23)x10(-6), and B(B+-->ppK(*+))=(10.3(+3.6+1.3)(-2.8-1.7))x10(-6). We also update B(B+-->ppK+)=(5.66(+0.67)(-0.57)+/-0.62)x10(-6) and present an upper limit on B(B0-->ppK(*0)) at the 90% confidence level. A common feature of the observed decay modes is threshold peaking in baryon pair invariant mass.

Journal Article↗
PubMed2004

Observation of the radiative decay D0-->phigamma.

We report the observation of the decay D0-->phigamma with a statistical significance of 5.4sigma in 78.1 fb(-1) of data collected by the Belle experiment at the KEKB e+e- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0-->phipi(0), phieta are also observed for the first time. We measure branching fractions B(D0-->phigamma)=[2.60(+0.70)(-0.61)(stat)+0.15-0.17(syst)] x 10(-5), B(D0-->phipi(0))=[8.01+/-0.26(stat)+/-0.47(syst)] x 10(-4), and B(D0-->phieta)=[1.48+/-0.47(stat)+/-0.09(syst)] x 10(-4).

Journal Article↗
PubMed2001

Electromagnetic moments of the beta-emitting nucleus 16N.

The nuclear magnetic dipole moment mu and electric quadrupole moment Q of the beta-emitting 16N(Ipi = 2(-), T(1/2) = 7.13 s) nucleus have been determined for the first time by detecting its beta-NMR in a MgO crystal and beta-NQR (nuclear quadrupole resonance) in a TiO (2) crystal to be /mu/ = (1.9859+/-0.0011) mu(N) and /Q/ = (17.9+/-1.7) mb, respectively. Although the prediction of mu given by the Hartree-Fock calculation agrees well with the experiment, an abnormally small effective charge for neutrons is required to account for the experimental Q.

Journal Article↗
PubMed1997

Flow cytometric analysis of leukocytes and reticulocytes stained with proflavine.

Proflavine, an acridine analog for industrial use, was used to stain blood cells. A drop of blood treated with ethylenediaminetetraacetic acid-2K was mixed with a 0.00001% solution of the dye and observed immediately by fluorescence microscopy with a green filter. Leukocytes, platelets, and reticulocytes were stained but mature red blood cells were not. Chromatin in the nuclei of all leukocytes and nucleoli of lymphocytes and monocytes had greenish-yellow fluorescence, and the kind of cell could be identified by the tone and intensity of this color. Granules in granulocytes were in green. Reticular fine-granular or granulofibrous structures in the reticulocytes were brownish. The proflavine could be used routinely in clinical laboratories because this single stain makes possible simultaneous differentiation of leukocytes and counting of reticulocytes.

DNA↗
PubMed1996

A tightly regulated expression system in Escherichia coli with SP6 RNA polymerase.

A tightly regulated gene-expression system was developed using SP6 RNA polymerase (RpoSP6). The RpoSp6-encoding gene (rpoSP6) was inserted into a mini-F plasmid (mini-F) and expression was controlled by the lactose promoter (P(lac)) and operator (O(lac)) on the plasmid. Therefore, a controlled expression system for the target genes can easily be constructed in various host strains by co-transformation of the system plasmid pFSP6 with other vector plasmids containing the genes linked to the SP6 promoters (P(SP6)). Using the lac gene linked to P(SP6) as a reporter, we evaluated the regulation of expression in this system in various host strains. Low-level expression of lac was detected in Escherichia coli harboring this expression system when RpoSP6 was uninduced, although very low activities of beta-galactosidase (beta-Gal) were observed which were independent of the presence of pFSP6. This basal level of beta-Gal activity was possibly derived, because the P(SP6) element has very weak activity for E. coli RNA polymerase (Rpo). These results showed that RpoSP6 seemed to be produced at very low levels in uninduced cells. Beta-GAl activity increased about 18-32-fold when the expression of rpoSP6 was induced, as compared with the beta-Gal activity when uninduced. The tight regulation of this system is superior to that of other known systems and it has a considerable advantage for gene expression in E. coli.

Base Sequence↗
PubMed1996

Molecular-pathological analysis of a patient with three synchronous squamous cell carcinomas in the aerodigestive tract.

A case of synchronous squamous cell carcinomas in the soft palate, larynx and esophagus is reported, along with findings of molecular-pathological analysis. A biopsy sample from the aryngeal carcinoma revealed well differentiated squamous cell carcinoma harboring two point mutations at codons 144 and 148 of the p53 gene but not at codon 299, and more than 50% of the cancer cells showed accumulation of p53 protein immunohistochemically. The esophageal tumor, which was moderately differentiated squamous cell carcinoma, showed immunoreactivity for p53 within the nuclei of 25-50% of cancer cells with a missense mutation at codon 299 but not at codon 144 or 148. This cancer also showed immunoreactivity for transforming growth factor alpha. On the other hand, the poorly differentiated squamous cell carcinoma in the soft palate showed negative immunoreactivity for p53 and no point mutation in exons 5 to 8 of the gene. These results suggest that the three synchronous squamous cell carcinomas arose as independent events.

Aged↗
PubMed1996

The immunological activity of a deletion mutant of influenza virus haemagglutinin lacking the globular region.

A deletion mutant of influenza virus haemagglutinin (HA; headless HA) lacking the globular region was expressed in CV-1 cells and detected with a monoclonal antibody, C179, which recognizes a conformational epitope in the middle of the stem region of HA and neutralizes all H1 and H2 subtypes. The cDNA coding for the headless HA was constructed from influenza virus A/Okuda/57 (H2N2), which was also used to select C179. The conformational epitope recognized by C179 was highly stable even after removal of the globular region. The survival rate of mice immunized with the headless HA and challenged with lethal influenza virus A/FM/l/47 (H1N1) was significantly higher than that of the control mice. The headless HA has the potential to induce cross-protection against influenza virus infection.

Animals↗
PubMed1995

Sse8387I, a useful eight base cutter for mammalian genome analysis (influence of methylation on the activity of Sse8387I).

To develop restriction enzymes that are useful for genome analysis, we previously performed screening and isolated Sse8387I from Streptomyces sp. strain 8387. Sse8387I is a restriction enzyme that recognizes 5'-CCTGCA/GG-3' and cleaves DNA at the site shown by the diagonal (Nucleic Acid Res., 18, 5637-5640). The present study evaluated the effects of methylation that is important when Sse8387I is used for genome analysis. Sse8387I lost cleavage activity after methylation of adenine or methylation of cytosine at any site in the recognition sequence. However, the recognition sequence of Sse8387I contains no CG sequence, which is the mammalian methylation sequence. In addition, we evaluated the effects of methylation of CG at sites other than the recognition sequence. The cleavage activity of Sse8387I was maintained even when CG sequences were present immediately before or after, or near the recognition sequence, and cytosine was methylated. These results suggest that CG methylation does not affect the cleavage activity of Sse8387I. Therefore, Sse8387I seems to be very useful for mammalian genome analysis.

5-Methylcytosine↗