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Biomedical subjects

M Iinuma

Publications and source records attributed to M Iinuma.

At least 19 recordsLinked to original sources
PubMed2006

Improved search for nu(mu) --> nu(e) oscillation in a long-baseline accelerator experiment.

We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level.

Journal Article↗
PubMed2005

Search for coherent charged pion production in neutrino-carbon interactions.

We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.

Journal Article↗
PubMed2005

Evidence for muon neutrino oscillation in an accelerator-based experiment.

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).

Journal Article↗
PubMed2005

Proton polarization with p-terphenyl crystal by integrated solid effect on photoexcited triplet state.

We have carried out the experiments for polarizing protons in single crystals of p-terphenyl doped with 0.1 mol% pentacene. The experiments have been performed in a magnetic field of 3 kG at room temperature or at 77 K. We obtained the polarization of 1.3% for protons in bulk at room temperature by using a pulsed dye-laser with the wavelength of 590 nm, the average power of 150 mW, and the repetition rate of 50 Hz. The polarization at 77 K reached 18% by irradiation with the dye-laser of 500 mW, 50 Hz and the same wavelength. The polarization of protons was measured by the neutron transmission method also. The result was consistent with that measured by the nuclear magnetic resonance.

Journal Article↗
PubMed2005

Antibacterial activity of alpha-mangostin against vancomycin resistant Enterococci (VRE) and synergism with antibiotics.

alpha-Mangostin, isolated from the stem bark of Garcinia mangostana L., was found to be active against vancomycin resistant Enterococci (VRE) and methicillin resistant Staphylococcus aureus (MRSA), with MIC values of 6.25 and 6.25 to 12.5 microg/ml, respectively. Our studies showed synergism between alpha-mangostin and gentamicin (GM) against VRE, and alpha-mangostin and vancomycin hydrochloride (VCM) against MRSA. Further studies showed partial synergism between alpha-mangostin and commercially available antibiotics such as ampicillin and minocycline. These findings suggested that alpha-mangostin alone or in combination with GM against VRE and in combination with VCM against MRSA might be useful in controlling VRE and MRSA infections.

Anti-Bacterial Agents↗
PubMed2001

Stilbenoids in lianas of Gnetum parvifolium.

Five new stilbene dimers were isolated from the lianas of Gnetum parvifolium in addition to known stilbenoids. The structures of the compounds were established on the basis of spectroscopic evidence, including long-range coupling and nuclear Overhauser effect experiments, in NMR spectrum. Among the isolates, 2b-hydroxyampelopsin F showed potent inhibitory activity in the Maillard reaction.

Acetylation↗
PubMed2000

High proton polarization by microwave-induced optical nuclear polarization at 77 K

Protons in naphthalene and p-terphenyl doped with pentacene have been polarized up to 32% and 18%, respectively, at liquid nitrogen temperature in a magnetic field of 0.3 T by means of microwave-induced optical nuclear polarization. The polarization was measured by nuclear magnetic resonance as well as by the neutron transmission method. The relaxation time of the proton polarization at 0.0007 T and 77 K was found to be almost 3 h and the polarization enhancement reached a record value of 8x10(4). The usefulness of the method in many areas of physics and chemistry is discussed.

Journal Article↗
PubMed2000

Stilbene oligomers in roots of Sophora davidii.

Three stilbene oligomers, davidiols A-C were isolated from the roots of Sophora davidii in addition to the seven known phenols, leachianone A, sophoraflavanones G, H and I, miyabenol C, alpha-viniferin and epsilon-viniferin. Their structures and relative configurations were established by means of 2D-NMR spectroscopy including COLOC and PSNOESY.

Magnetic Resonance Spectroscopy↗
PubMed2000

Stilbenoids in the stem bark of Hopea parviflora.

From the bark of Hopea parviflora, two stilbenoids, named (+)-parviflorol and (-)-ampelopsin A, were isolated in addition to three known compounds: (+)-balanocarpol, (-)-epsilon-viniferin and (-)-hopeaphenol. Their structures were determined by analysis of spectral data, including 2D NMR and NOE experiments, respectively.

Magnetic Resonance Spectroscopy↗
PubMed2000

Oligostilbenoids in stem bark of Vatica rassak.

Three resveratrol oligomers, vaticanols. A, B and C, as well as three known stilbenoids, resveratrol, piceid and epsilon-viniferin were isolated from the stem bark of Vatica rassak (Dipterocarpaceae). Their structures were determined by the analysis of NMR spectral data including the application of 2D methods.

Benzofurans↗
PubMed2000

Reduction of membrane fluidity by antibacterial sophoraflavanone G isolated from Sophora exigua.

Sophoraflavanone G (5,7,2',4'-tetrahydroxy-8-lavandulylflavanone) has been referred as a phytochemical with the intensive antibacterial activity. To elucidate the pharmacological mechanism underlying an antibacterial action, sophoraflavanone G was isolated from Sophora exigua, thereafter its effect on membrane fluidity was studied using model membranes and compared with less active naringenin lacking 8-lavandulyl and 2'-hydroxyl groups. Highly purified sophoraflavanone G of 0.05-5 microg/ml, corresponding to the minimum growth inhibitory concentrations against various bacteria, significantly increased fluorescence polarization of the liposomes prepared from 1,2-dipalmitoyl-L-alpha-phosphatidylcholine and 1-palmitoyl-2-oleoyl-L-alpha-phosphatidylcholine. Such increases were found in both liposomes measured with two fluorescent probes to indicate an alteration of membrane fluidity in hydrophilic and hydrophobic regions, suggesting that sophoraflavanone G reduces the fluidity of outer and inner layers of membranes. Although naringenin also showed the membrane effect, it needed concentrations over 2.5 microg/ml to induce a significant reduction of membrane fluidity. Sophoraflavanone G is considered to exert an antibacterial effect by reducing the fluidity of cellular membranes.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2000

Diterpenoid acids from Grindelia nana.

Two new norditerpenoid acids of the labdane-type (norgrindelic acids), 4,5-dehydro-6-oxo-18-norgrindelic acid (1) and 4beta-hydroxy-6-oxo-19-norgrindelic acid (2), as well as a new grindelic acid derivative, 18-hydroxy-6-oxogrindelic acid (3), were isolated from the aerial parts of Grindelia nana. In addition, the known compounds, 6-oxogrindelic acid, grindelic acid, methyl grindeloate, 7alpha,8alpha-epoxygrindelic acid, and 4alpha-carboxygrindelic acid were also isolated. The structures of the new compounds were characterized on the basis of spectroscopic analysis.

Asteraceae↗
PubMed2000

Rearranged abietane diterpenoids from Clerodendrum mandarinorum.

Five new abietane derivatives which have a commonly rearranged abietane skeleton contained a 17(15-->16),18(4-->3)-diabeo-abietane framework, mandarones D-H, were isolated from the stem of Clerodendrum nmantarinorum Diels (Verbenaceae). The structures were characterized as (16S)-12,16-epoxy-11-hydroxy-17(15-->16), 18(4-->3)-diabeo-abieta-3,5,8,11,13-pentaene-7-one (mandarone D, 1), 12,16-epoxy-11,14-dihydroxy-17(15-->16),18(4-->3)-diabeo-abieta-3,5,8,11, 13,15-hexaene-7-one (mandarone E, 2), 12,16-epoxy-6,11,14-trihydroxy-17(15-->16),18(4-->3)-diabeo-abieta-3,5,8,11,13,15-hexaene-7-one (mandarone F, 3),12,16-epoxy-11,14-dihydroxy-6-methoxy-17(15-->16),18(4-->3)-diabeo-abieta-3,5,8,11,13,15-hexaene-2,7-dione (mandarone G, 4) and 12,16-epoxy-11,14-dihydroxy-17(15-->16),18(4-->3)-diabeo-abieta-3,5,8,11,13,15-hexaene-1,7-dione (mandarone H, 5) respectively, mainly based on the spectral analysis and by comparison with those of closely related compounds.

Chromatography↗
PubMed2000

Stilbenoids isolated from stem bark of Shorea hemsleyana.

Two new stilbene glucosides [(+)-alpha-viniferin 13b-O-beta-glucopyranoside and resveratrol 12-C-beta-glucopyranoside] and two new resveratrol oligomers, hemsleyanols A and B, were isolated from the bark of Shorea hemsleyana along with four known resveratrol oligomers. The structures of the isolates, including the relative configurations, were established by spectroscopic data involving long-range coupling and nuclear Overhauser effect experiments.

Magnetic Resonance Spectroscopy↗
PubMed1999

Antitumor agents 200. Cytotoxicity of naturally occurring resveratrol oligomers and their acetate derivatives.

Eleven resveratrol oligomers and six acetylated derivatives were evaluated for in vitro cytotoxicity against a panel of human tumor cell lines. The acetate of (-)-ampelopsin A (12) showed potent and selective cytotoxic activity with ED50 values of 0.6, 0.7 and 2.0 microg/mL against KB, 1A9 and MCF-7 cells, respectively. Hopeaphenol (10) and pallidol hexaacetate (13) also showed significant cytotoxicity against KB cells with ED50 values of 1.2 and 1.6 microg/mL, respectively.

Acetates↗