Biomedical subjects
Publications and source records attributed to H Muramatsu.
Using 13.8 fb(-1) of data collected at or just below the Upsilon(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D0-->gammagamma. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions B(D0-->gammagamma)/B(D0-->pi(0)pi(0))<0.033 and B(D0-->gammagamma)<2.9 x 10(-5).
BACKGROUND: In recent years, there has been an increasing number of cases of early gastric cancer (T1, NX) with intramucosal invasion, which are untreatable by surgical or endoscopic mucosal resection (EMR) because of their high risk. Currently, no adequate treatment is available for such patients. AIM: The main objective of this study was to evaluate whether argon plasma coagulation (APC) is an effective and safe modality for treating early gastric cancer untreatable by surgical resection or EMR. METHODS: The study group comprised 20 men and seven women diagnosed with gastric cancer with intramucosal invasion who were considered poor candidates for surgical resection or EMR due to risk factors such as severe cardiac failure or thrombocytopenia. Irradiation conditions for APC treatment were determined using swine gastric mucosa. We used an argon gas flow of 2 l/min at a power setting of 60 W and a maximum irradiation time of 15 s/cm(2). The follow up period of the 27 patients ranged from 18 to 49 months (median 30 months). RESULTS: All lesions were irradiated easily, including areas anatomically difficult for EMR such as the gastric cardia or the posterior wall of the upper gastric body. In 26 of 27 patients (96%) there was no evidence of recurrence during the follow up period (median 30 months). One patient showed recurrence six months after the treatment but was successfully retreated. No serious complications were found in any of the 27 patients but three patients (11%) experienced a feeling of abdominal fullness. INTERPRETATION: APC is a safe and effective modality for treatment of early gastric cancer with intramucosal invasion untreatable by surgical resection or EMR. However, further observations are necessary to determine the long term prognosis of patients undergoing this treatment.
Using the combined CLEO II and CLEO II.V data sets of 9.1 fb(-1) at the Upsilon(4S), we measure properties of psi mesons produced directly from decays of the B meson, where "B" denotes an admixture of B+, B-, B0, and B;(0), and "psi" denotes either J/psi(1S) or psi(2S). We report first measurements of psi polarization in B-->psi(direct)X: alpha(psi(1S))=-0.30(+0.07)(-0.06)+/-0.04 and alpha(psi(2S))=-0.45(+0.22)(-0.19)+/-0.04. We also report improved measurements of the momentum distributions of psi produced directly from B decays, correcting for measurement smearing. Finally, we report measurements of the inclusive branching fraction for B-->psiX and B-->chi(c1)X.
In e(+)e(-) collisions using the CLEO detector, we have studied the decay of the D0 to the final state K(0)(S)pi(+)pi(-) with the initial flavor of the D0 tagged by the decay D(*+)-->D0pi(+). We use the Dalitz technique to measure the resonant substructure in this final state and clearly observe ten different contributions by fitting for their amplitudes and relative phases. We observe a K(*)(892)(+)pi(-) component which arises from doubly Cabibbo suppressed decays or D0-D0; mixing.
We report on a search for charmless hadronic B decays to the three-body final states K(0)(S)h(+)pi(-), K(+)h(-)pi(0), K(0)(S)h(+)pi(0) (h(+/-) denotes a charged pion or kaon), and their charge conjugates, using 13.5 fb(-1) of integrated luminosity produced near sqrt[s]=10.6 GeV, and collected with the CLEO detector. We observe the decay B-->K0pi(+)pi(-) with a branching fraction (50(+10)(-9)(stat.)+/-7(syst.))x10(-6) and the decay B-->K(*+)(892)pi(-) with a branching fraction (16(+6)(-5)(stat.)+/-2(syst.))x10(-6).
Using the CLEO detector at the Cornell Electron Storage Ring we have observed the Omega(0)(c) (css ground state) in the decay Omega(0)(c)-->Omega(-)e(+)nu(e). We find a signal of 11.4+/-3.8(stat) events. The probability that we have observed a background fluctuation is 7.6x10(-5). We measure B(Omega(0)(c)-->Omega(-)e(+)nu(e)).sigma(e(+)e(-)-->Omega(0)(c)X)=(42.2+/-14.1(stat)+/-5.7(syst)) fb and R=[Gamma(Omega(0)(c)-->Omega(-)pi(+))]/[Gamma(Omega(0)(c)-->Omega(-)enu(e))]=00.41+/-0.19(stat)+/-0.04(syst). This is the first statistically significant observation of an individual decay mode of the Omega(0)(c) in e(+)e(-) annihilation and the first example of a baryon decaying via beta emission, where no quarks from the first generation participate in the reaction.
A significant reduction of absorption for single gamma photons has been experimentally observed by studying Mössbauer spectra of 57Fe in a FeCO3 crystal. The experimental results have been explained in terms of a quantum interference effect involving nuclear level anticrossing due to the presence of a combined magnetic dipole and electric quadrupole interaction.
We report the first observation of the exclusive decays B-->D((*))K(*-), using 9.66 x 10(6) BB pairs collected at the Upsilon(4S) with the CLEO detector. We measure the following branching fractions: B(B--->D(0)K(*-)) = (6.1+/-1.6+/-1.7)x10(-4), B(B(0)-->D(+)K(*-)) = (3.7+/-1.5+/-1.0)x10(-4), B(B(0)-->D(*+)K(*-)) = (3.8+/-1.3+/-0.8)x10(-4), and B(B--->D(*0)K(*-)) = (7.7+/-2.2+/-2.6)x10(-4). The B-->D(*)K(*-) branching ratios are the averages of those corresponding to the 00 and 11 helicity states. The errors shown are statistical and systematic, respectively.
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The seasonal variation of 222Rn concentrations in the air of tunnels constructed during World War II at Nagano City has been investigated. The determination of 222Rn concentrations in tunnel air was performed using a solid-state nuclear track detector technique. The monthly radon concentrations changed smoothly, decreasing towards winter and increasing towards summer, and it was found that the concentrations strongly correlate with the temperature difference between the inside and the outside of the tunnel. In the innermost areas of the tunnel, the maximum concentration was observed in July, its value being about 6500 Bq m (-3). The concentrations of radon in the tunnel air decrease exponentially towards the openings of the tunnel, which indicates that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air. These observations lead to the conclusion that the seasonal variation of the radon concentration in the tunnel air is mainly caused by a convection current due to a stack effect induced by the temperature difference between the tunnel air and the outside air.
We have developed a video signal processor for improving the operability and function of scanning near-field optical microscopy (SNOM). The video signal processor applies a CCD imaging device as a variable area photo-sensor in the SNOM unit instead of conventional photo-detectors. The signal processor converts the intensity of a selected area in video frames to a numerical value with a rate of 30 Hz. Consequently, the CCD imaging device can be used as a photo-detector of variable areas and positions for detecting a small area of a optical probe position. The need for a precise optical axis alignment is relaxed due to the large sensing area of the CCD device. Using the video signal processor, near-field optical and topographic images have been obtained by SNOM/AFM system simultaneously. By adding a spectrometer between the SNOM unit and the CCD device, the spectrum signal of selected wavelength ranges has been monitored by the video signal processor to provide an optical image.
An effective method of DNA stretching on mica surfaces is proposed for an extremely low concentration of DNA. The method is based on an electric field and well applied on the concentration range from 57 x 10(-3) to 57 x 10(-6) ng/ml. The stretching exists in a gap between positive and negative electrodes. The difference in the stretching efficiency among the different surfaces of bare mica, Mg2+ soaked mica and AP-mica is discussed. The best performance of the stretching is found from the surface of AP-mica for the same experimental condition of sample concentration and applied voltage. Finally, from a Scanning near-field optical microscope image, it is found that well-stretched DNA molecules have shown more similar optical resolution, which is inferred from an optical fiber probe, itself.
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High-resolution fluorescence imaging of lambda-phage DNA molecules, intercalated with the dye YOYO-1, has been performed by a SNOM/AFM based on a bent-type optical fiber probe. A modified design of the optical probe has been made, and successful near-field optical resolution has been obtained for the strongly stretched lambda-phage DNA molecules. The best optical resolution was estimated at 45 nm for the dye-intercalated single lambda-DNA molecules by a mean width evaluation. In our comparison between the far-field fluorescence and high-resolution near-field fluorescence images for the DNA, it has been found that the near-field images much better defined the intercalation state of the dye. Finally, the relation between the DNA shapes and the dye distribution states, and the discrimination between the double-stranded and single-stranded DNA molecules, are discussed by comparing the topography and fluorescence images of the SNOM/AFM.
M50054, 2,2'-methylenebis (1,3-cyclohexanedione), was identified as a novel inhibitor of apoptosis (programmed cell death) using an in vitro cell death assay system induced in human Fas-expressing WC8 cells by soluble human Fas ligand. Furthermore, M50054 inhibited the apoptotic cell death of U937, a human monocytic leukemic cell line, induced by anticancer agents such as etoposide; it was also confirmed that M50054 inhibited apoptotic features such as DNA fragmentation and phosphatidylserine exposure in these cells. These anti-apoptotic effects were attributable to inhibition of caspase-3 activation. Additionally, M50054 significantly inhibited anti-Fas-antibody-induced elevation of plasma alanine aminotransferase and aspartate aminotransferase. Alopecia (hair loss) symptoms were also significantly improved with topical treatment with M50054. In conclusion, M50054 inhibits apoptosis induced by a variety of stimuli via inhibition of caspase-3 activation, and may thus be effective for hepatitis and chemotherapy-induced alopecia.
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Midkine (MK) is a heparin binding multifunctional protein that promotes cell survival and cell migration. MK was found to bind to 37-kDa laminin binding protein precursor (LBP), a precursor of 67-kDa laminin receptor, with K(d) of 1.1 nM between MK and LBP-glutathione-S-transferase fusion protein. The binding was inhibited by laminin, anti-LBP, amyloid beta-peptide, and heparin; the latter two are known to bind to MK. In CMT-93 mouse rectal carcinoma cells, LBP was mostly located in the cytoplasm as revealed by immunostaining with anti-LBP antibody. That a portion of LBP or 67-kDa laminin receptor was located at the surface of these cells was verified by inhibition of cell attachment to laminin-coated dishes by anti-LBP antibody. When MK was added to culture medium of these cells, a part of LBP migrated to the nucleus. The movement occurred concomitantly with nuclear transport of biotin-labeled MK. These findings suggested that the binding of MK to LBP caused nuclear translocation of the molecular complex.