Biomedical subjects

M Hagiwara

Publications and source records attributed to M Hagiwara.

At least 19 recordsLinked to original sources

PubMed2006

Experimental studies of the deuteron-induced activation cross-sections on natAg.

Excitation functions were measured for the (nat)Ag(d,x)(105,106m,110m)Ag, (nat)Ag(d,x)(107,109)Cd and (27)Al(d,x)(24)Na reactions by the stacked-foil activation technique and high-resolution gamma-spectroscopy over the energy range 0.44-40 MeV. The thick target integral yields were deduced using the measured cross-sections. No experimental data on the (nat)Ag+d process are available in the literature above 27 MeV. The nuclides (105)Ag, (106m)Ag and (109)Cd produced with deuteron induced activation of natural silver have suitable yields and decay characteristics important for thin layer activation (TLA) analysis. The cross-section for the production of (107)Cd and (109)Cd is significantly large. Therefore, the Ag+d process can be an efficient route for the production of isotope with a medium energy accelerator. The results of the model calculation using the TALYS code are not consistent with the present data. A large shift in the incident energy is found in TALYS calculations.

Journal Article↗

PubMed2006

X-ray diffractometer combining synchrotron radiation and pulsed magnetic fields up to 40 T.

A synchrotron X-ray diffractometer incorporating a pulsed field magnet for high fields up to 40 T has been developed and a detailed description of this instrument is reported. The pulsed field magnet is composed of two coaxial coils with a gap of 3 mm at the mid-plane for passage of the X-rays. The pixel detector PILATUS 100K is used to store the diffracted X-rays. As a test of this instrument, X-ray diffraction by a powder sample of the antiferromagnet CoO is measured below the Néel temperature. A field-dependent lattice distortion of CoO due to magnetostriction is observed up to 38 T.

Journal Article↗

PubMed2006

Tomonaga-Luttinger liquid in a quasi-one-dimensional S = 1 antiferromagnet observed by specific heat measurements.

Specific-heat experiments on single crystals of the S = 1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C9H24N4)(NO2)ClO2 (NTENP) have been performed in magnetic fields applied both parallel and perpendicular to the spin chains. We have found for the parallel field configuration that the magnetic specific heat (C(mag)) is proportional to temperature (T) above a critical field H(c), at which the energy gap vanishes, in a temperature region above that of the long-range ordered state. The ratio C(mag)/T increases as the magnetic field approaches H(c) from above. The data are in good quantitative agreement with the prediction of the c= 1 conformal field theory in conjunction with the velocity of the excitations calculated by a numerical diagonalization, providing conclusive evidence for a Tomonaga-Luttinger liquid.

Journal Article↗

PubMed2006

Mitochondrial dysfunction in focal segmental glomerulosclerosis of puromycin aminonucleoside nephrosis.

Focal segmental glomerular sclerosis (FSGS) is a major renal complication of mitochondrial (mt) cytopathies. The present study was designed to investigate the possibility of mtDNA lesion accumulation in podocytes, which are a primary pathogenic site of FSGS, during the development of glomerulopathy in puromycin aminonucleoside nephrosis (PAN). Two renal pathological phases of PAN, nephrosis phase and FSGS phase were studied. We investigated the expression of mt proteins, the copy number of a 4834 base-pair deletion (del-mtDNA), and total mtDNA content by real-time polymerase chain reaction, as well as the mRNA expression levels of the mt transcription factor A (mtTFA) and the nuclear respiratory factor-1 (NRF-1) in glomeruli. The mtDNA encoded cytochrome c oxidase subunit I (COX I) protein level was identical to control in nephrosis phase, however, a 45% reduction was seen in FSGS phase. Intraglomerular del-mtDNA was 16-21 times higher than controls in both phases, but the proportion of this mutation was <1% of total mtDNA. The copy number of total mtDNA at nephrosis phase increased up to 241%, whereas, it decreased to 34% at FSGS phase in glomeruli. The mRNA expression of both mtTFA and NRF-1 was upregulated at nephrosis phase, but mtTFA was downregulated at FSGS phase. A reduction in mtDNA copy number resulted in reduced levels of COX I in glomeruli at FSGS phase, suggesting that mt dysfunction by mtDNA depletion potentially plays a key role in the pathogenesis of FSGS in PAN.

Animals↗

PubMed2006

[Usefulness of ultrasonically activated scalpel for pulmonary resection in video-assisted thoracoscopic surgery].

We evaluated the reliability and efficacy of the ultrasonically activated scalpel (Harmonic Scalpel) for pulmonary resection in video-assisted thoracoscopic surgery (VATS). Fifty-six cases of primary or metastatic lung cancer with history of lobectomy or segmentectomy from July 2003 to June 2006 were investigated. The ultrasonically activated scalpel was used to separate aborted lobulation and segment in the surgery. The outcome of the operation using the ultrasonically activated scalpel revealed the mean operation time of 224.5 minutes and mean blood loss volume of 116.7 ml. The chest drainage catheter was removed at the postoperative day 3.4 and hospitalization lasted 10.4 days on average. By means of statistical analysis, no significant differences were noted when compared with the cases using surgical stapler to separate the lobules or segments of the lungs. Histopathological results showed destruction of alveolar structures and denaturation of cells at the cut surface of the resected lung through the use of the ultrasonically activated scalpel. This method resulted in good lung expansion and preservation of the residual lung volume. Furthermore, it prevented postoperative air leakage by appropriate treatment to the cut surfaces of the residual lung. Indeed, the method appears to be useful in the separation of lung tissues in severe aborted lobulation and segmentectomy by VATS.

Aged↗

PubMed2005

Spin excitations in an anisotropic bond-alternating quantum s = 1 chain in a magnetic field: contrast to haldane spin chains.

Inelastic neutron scattering experiments on the S = 1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C9D24N4)(NO2)ClO4 have been performed under magnetic fields below and above a critical field Hc at which the energy gap closes. Normal field dependence of Zeeman splitting of the excited triplet modes below Hc has been observed, but the highest mode is unusually small and smears out with increasing field. This can be explained by an interaction with a low-lying two magnon continuum at q(parallel) = pi that is present in dimerized chains but absent in uniform ones. Above Hc, we find only one excited mode, in stark contrast with three massive excitations previously observed in the structurally similar Haldane-gap material NDMAP [A. Zheludev, Phys. Rev. B 68, 134438 (2003)].

Journal Article↗

PubMed2005

Activation cross-sections of long-lived products of proton-induced nuclear reactions on zinc.

In the frame of a systematic study of excitation functions induced by medium energy protons, the activation cross-sections on natural zinc were investigated for different applications. Excitation functions for production of 66,67Ga, 62,65,69mZn, 64Cu, 57Ni, 55,56,57,58Co and 52,54Mn radioisotopes were measured by the stacked foil technique in the energy range of 26-67 MeV. Results were compared with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. Experimental data are presented for the first time for most of the products in the investigated energy range. Applications of the measured data for validating the cross-sections on highly enriched isotopic Zn targets and for thin layer activation method are discussed.

Computer Simulation↗

PubMed2005

Experimental studies on excitation functions of the proton-induced activation reactions on silver.

Excitation functions were measured for the production of 106m,105Ag, 103,101,100Pd, 105,102,101m,100,99Rh and 97Ru via proton-induced activation reactions on natural silver using a stacked foil technique in the energy range 11-80 MeV. The residual activity measurements were carried out nondestructively by the high-resolution HPGe gamma-ray spectroscopy. Thick target integral yields were deduced using the measured cross-sections from the respective threshold energies of the investigated reactions up to 80 MeV. The present work gives new results for the investigated radionuclides. The data in MENDL-2P deduced with the theoretical model code ALICE-IPPE are consistent in shape with the measured values, but show disagreement in magnitude.

Journal Article↗

PubMed2005

Experimental studies on excitation functions of the proton-induced activation reactions on yttrium.

Proton-induced activation cross-sections were measured for the (89)Y(p,x)(89,88,86)Zr, (89)Y(p,x)(88,87,87 m,86)Y, (89)Y(p,x)(85,83,82)Sr and (89)Y(p,x)(84,83)Rb reactions by a stacked foil technique in the energy range 15-80 MeV which was covered by two separate measurements for 15-50 and 32-80 MeV energy range with 50 and 80 MeV incident protons. The differences between the results of two irradiations were found within 6% in the overlapping energy regions. The production yields for the long-lived products like (88)Zr, and (88)Y are significantly larger than that of (nat)Mo+p, (nat)Nb+p and (nat)Zr+p processes. The productions of the medical isotopes, (85)Sr and (83)Sr are also effective by Y+p process using an 80 MeV beam. Thick target integral yields were also deduced using the measured cross-sections. The (87)Y, (88)Y, (88)Zr and (89)Zr radionuclides have suitable yields and decay characteristics important for thin-layer activation (TLA) analysis.

Journal Article↗

PubMed2004

Experimental studies on the proton-induced activation reactions of molybdenum in the energy range 22-67 MeV.

The production cross-sections of (99,93m)Mo, (96,95,95m,94)Tc, (96,95,92m,90)Nb, (89,88,86)Zr and (88,87,86)Y radionuclides for proton-induced reactions on molybdenum were measured with molybdenum targets of natural isotopic composition using a stacked-foil activation technique in the energy range 22-67 MeV. The thick target integral yields were also deduced for each reaction using the measured cross-sections from the respective threshold up to 67 MeV. The results have given new data for all of the investigated radionuclides. The results of the present experiment showed excellent agreement with the earlier reported data in the lower energy region.

Journal Article↗

PubMed2003

Zeeman levels with exotic field dependence in the high field phase of an S=1 Heisenberg antiferromagnetic chain.

We have performed electron spin resonance measurements over a wide frequency and magnetic field range on a single crystal of the S=1 quasi-one-dimensional Heisenberg antiferromagnet Ni(C5H14N2)2N3(PF6). We observed gapped excitation branches above the critical field H(c) where the Haldane gap closes. These branches are analyzed by a phenomenological field theory using the complex-field phi(4) model. A satisfactory agreement between experiment and theory is obtained.

Journal Article↗

PubMed2003

Nanostructured Ti-based multi-component alloys with potential for biomedical applications.

A group of Ti(60)Cu(14)Ni(12)Sn(4)M(10) (M=Nb, Ta, Mo) alloys was prepared using arc melting and copper mold casting. The as-prepared alloys have a composite microstructure containing a micrometer-sized dendritic beta-Ti(M) phase dispersed in a nanocrystalline matrix. These new alloys exhibit a low Young's modulus in the range of 59-103 GPa, and a high yield strength of 1037-1755 MPa, together with large plastic strains. The combination of high strength and low elastic modulus offers potential advantages in biomedical applications.

Alloys↗

PubMed2003

Effects of combination therapy with a luteinizing hormone-releasing hormone agonist and chlormadinone acetate on rat prostate weight and plasma testosterone levels.

We investigated whether the combination of chlormadinone acetate (CMA) and a luteinizing hormone releasing hormone (LH-RH) agonist, leuprorelin acetate (leuprorelin), more markedly decreased ventral prostate and seminal vesicle weights and plasma sex hormone levels in male rats. Four weeks after administration of 0.28, 0.84 or 2.8 mg/kg of leuprorelin, ventral prostate weights significantly decreased (53.8, 54.4 and 64.1%) and the plasma testosterone levels significantly lowered, but not dose-dependently. After repetitive administrations of 3 and 30 mg/kg/day of CMA, the rates of ventral prostatic atrophy were 37.1 and 65.9%, respectively. Although there was no change in the plasma testosterone level at 3 mg/kg, 30 mg/kg of CMA significantly decreased the level. A combination of leuprorelin (0.28 mg/kg) and CMA (3 or 30 mg/kg) more potently induced ventral prostatic and seminal vesicle atrophy than leuprorelin alone. Furthermore, a combination of leuprorelin and CMA (30 mg/kg) more markedly decreased the plasma testosterone level. According to the pharmacokinetic data for CMA in male rats, the doses of CMA correspond to the clinical dose. These findings suggest that combination therapy with an LH-RH agonist and CMA is more useful than therapy with the agonist alone in the treatment of prostate cancer.

Androgen Antagonists↗

PubMed2001

Identification of a novel kinesin-related protein, KRMP1, as a target for mitotic peptidyl-prolyl isomerase Pin1.

Mitosis utilizes a number of kinesin-related proteins (KRPs). Here we report the identification of a novel KRP termed KRMP1, which has a deduced 1780-amino acid sequence composed of ternary domains. The amino-terminal head domain is most similar to the kinesin motor domain of the MKLP-1 subfamily and has an intrinsic ATPase activity that is diminished by substituting the consensus Lys-168 with Arg. The central stalk domain is predicted to form a long alpha-helical coiled-coil, and can interact with each other in vivo. An in vivo labeling experiment revealed that KRMP1 is phosphorylated, and we also found that the region within the tail domain containing Thr-1604 as the cdc2 kinase phosphorylation site differs from the bimC box conserved in the bimC subfamily of KRPs. Immunofluorescence analysis showed that endogenous KRMP1 was localized predominantly to the cytoplasm during interphase and dispersed throughout the cell during mitosis. Consistent with this finding, overexpressed KRMP1 was detected in a complicated nuclear or cytoplasmic pattern reflecting multiple nuclear localization/export signals. Furthermore, KRMP1 interacted with the mitotic peptidyl-prolyl isomerase Pin1 in vivo, and an in vitro interaction was detected between the tail domain of KRMP1 and the WW domain of Pin1. Overexpression of KRMP1 caused COS-7 cells to arrest at G(2)-M, and co-expression of Pin1 reversed this effect, indicating their physiological interaction. Together, our results suggest that KRMP1 is a mitotic target regulated by Pin1 and vice versa.

Amino Acid Sequence↗

PubMed2001

Robust oscillations within the interlocked feedback model of Drosophila circadian rhythm.

A mechanism for generating circadian rhythms has been of major interest in recent years. After the discovery of per and tim, a model with a simple feedback loop involving per and tim has been proposed. However, it is recognized that the simple feedback model cannot account for phenotypes generated by various mutants. A recent report by Glossop, Lyons & Hardin [Science286, 766 (1999)] on Drosophila suggests involvement of another feedback loop by dClk that is interlocked with per-tim feedback loop. In order to examine whether interlocked feedback loops can be a basic mechanism for circadian rhythms, a mathematical model was created and examined. Through extensive simulation and mathematical analysis, it was revealed that the interlocked feedback model accounts for the observations that are not explained by the simple feedback model. Moreover, the interlocked feedback model has robust properties in oscillations.

Animals↗

PubMed2001

Cloning of human PRP4 reveals interaction with Clk1.

Prp4 is a protein kinase of Schizosaccharomyces pombe identified through its role in pre-mRNA splicing, and belongs to a kinase family including mammalian serine/arginine-rich protein-specific kinases and Clks, whose substrates are serine/arginine-rich proteins. We cloned human PRP4 (hPRP4) full-length cDNA and the antiserum raised against a partial peptide of hPRP4 recognized 170-kDa polypeptide in HeLa S3 cell extracts. Northern blot analysis revealed that hPRP4 mRNA was ubiquitously expressed in multiple tissues. The extended NH(2)-terminal region of hPRP4 contains an arginine/serine-rich domain and putative nuclear localization signals. hPRP4 phosphorylated and interacted with SF2/ASF, one of the essential splicing factors. Indirect immunofluorescence analysis revealed that endogenous hPRP4 was distributed in a nuclear speckled pattern and colocalized with SF2/ASF in HeLa S3 cells. Furthermore, hPRP4 interacted directly with Clk1 on its COOH terminus, and the arginine/serine-rich domain of hPRP4 was phosphorylated by Clk1 in vitro. Overexpression of Clk1 caused redistribution of hPRP4, from the speckled to the diffuse pattern in nucleoplasm, whereas inactive mutant of Clk1 caused no change of hPRP4 localization. These findings suggest that the NH(2)-terminal region of hPRP4 may play regulatory roles under an unidentified signal transduction pathway through Clk1.

Amino Acid Sequence↗

PubMed2001

Regulatory domain of protein stability of human P51/TAP63, a P53 homologue.

The amino terminal of human P51/TAp63, a P53 homologue, possesses a transactivation domain involved in the activation of its target genes by binding to DNA elements responsive to the p53 protein family. Using a series of amino terminal deletions, the transactivation domain was mapped between amino acid residues 50 to 69. This domain also regulates protein stability in a proteasome-dependent manner, and Ser51 and Ser68 were found to be essential for this stability. Our results suggest that P51 activity is greatly affected by protein stability.

Amino Acid Sequence↗

PubMed2001

Endoscopic evaluation of centrally located early squamous cell carcinoma of the lung.

BACKGROUND: Lung-sparing treatment recently has become a choice in the treatment of patients with early hilar lung carcinoma. To select the method of treatment, it is important to evaluate the histologic extent of the tumor using endoscopy. METHODS: A total of 46 patients who underwent surgery for an endoscopically evaluated early lung carcinoma of the tracheobronchial tree were analyzed. Initial surgery was performed in 16 patients and in 30 patients surgery was performed after preoperative laser therapy. The endoscopic findings were classified into three types: superficial, nodular, and polypoid. In the resected lung, the greatest tumor dimension, the depth of mural invasion, the presence of microscopic blood and lymph vessel invasion, and metastases to the dissected lymph nodes were examined. RESULTS: The mean greatest tumor dimensions were 14.6 +/- 7.3 mm (mean +/- standard deviation) in the nodular group, 23.3 +/- 12.8 mm in the superficial group, and 19.0 +/- 9.2 mm in the polypoid group. The greatest tumor dimension in the superficial group was significantly larger than that in the nodular group (P < 0.01). Preoperative endoscopic diagnosis of early hilar lung carcinoma was correct histologically in 34 of 46 cases (74.0%). Hilar lymph node metastases (N1), extrabronchial invasion, and extension to the peripheral bronchus were recognized in 12 cases. Complete disappearance of the tumor due to preoperative laser therapy was confirmed in eight patients. Lymph node metastasis was not found when the greatest tumor dimension measured < 8 mm. The overall absolute 5-year survival rate was 76.0% for all patients, 87.1% for the surgery alone group, and 70.0% for the surgery after preoperative laser therapy group. CONCLUSIONS: Curative treatment of early hilar lung carcinoma is possible using photodynamic therapy alone when the tumor size is < or = 8 mm and the lesion does not extend to the peripheral bronchus.

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