Biomedical subjects

S Hasegawa

Publications and source records attributed to S Hasegawa.

At least 19 recordsLinked to original sources

PubMed2006

Measurement of the Gerasimov-Drell-Hearn Integrand for 2H from 200 to 800 MeV.

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200<Egamma<800 MeV. The experiment used a 4pi detection system, a circularly polarized tagged photon beam and a frozen-spin target which provided longitudinally polarized deuterons. The contribution to the Gerasimov-Drell-Hearn sum rule for the deuteron determined from the data is 407+/-20(stat)+/-24(syst) mu b for 200<Egamma<800 MeV.

Journal Article↗

PubMed2006

Role of spin-orbit coupling and hybridization effects in the electronic structure of ultrathin Bi films.

The electronic structure of Bi(001) ultrathin films (thickness > or =7 bilayers) on Si(111)-7x7 was studied by angle-resolved photoemission spectroscopy and first-principles calculations. In contrast with the semimetallic nature of bulk Bi, both the experiment and theory demonstrate the metallic character of the films with the Fermi surface formed by spin-orbit-split surface states (SSs) showing little thickness dependence. Below the Fermi level, we clearly detected quantum well states (QWSs) at the M point, which were surprisingly found to be non-spin-orbit split; the films are "electronically symmetric" despite the obvious structural nonequivalence of the top and bottom interfaces. We found that the SSs hybridize with the QWSs near M and lose their spin-orbit-split character.

Journal Article↗

PubMed2006

Finasteride 1 mg has no inhibitory effect on omeprazole metabolism in extensive and poor metabolizers for CYP2C19 in Japanese.

OBJECTIVE: To examine the inhibitory effect of finasteride 1 mg on the metabolism of omeprazole in genetically determined extensive (EMs) and poor metabolizers (PMs) for CYP2C19 in young healthy Japanese male subjects. METHODS: Twenty-four volunteers participated in this study, among whom 12 were homozygous EMs and 12 were PMs for CYP2C19. A single center, controlled, randomized, open, crossover study with a 5 day washout between the two study periods was performed. Each of the six EMs and PMs received a single oral 20 mg dose of omeprazole on day 1 (treatment I). After a 5 day washout period, these subjects received 1 mg of finasteride once a day for three consecutive days, and a single oral 20 mg dose of omeprazole was co-administered on day 3 (treatment II). The 12 other EMs and PMs received treatments I and II in reverse. Plasma samples were collected for up to a 12 hours postdose of omeprazole, and the pharmacokinetic parameters of omeprazole were determined. RESULTS: The geometric mean ratio (GMR) for the AUC((0-12 hr)) of omeprazole when co-administered with finasteride/omeprazole alone is 1.13 (90%CI, 1.03, 1.25) and 0.96 (0.88, 1.05) in EMs and PMs, respectively. Finasteride did not significantly alter C(max), T(max) and t(1/2) in both genotypes. CONCLUSION: Finasteride 1 mg, widely used for the treatment of androgenetic alopecia in men, did not meaningfully increase omeprazole exposure (20 mg) in both EMs and PMs for CYP2C19. These results indicate that finasteride does not meaningfully inhibit CYP2C19 activity in vivo at the dose of 1 mg.

Adult↗

PubMed2006

The biocompatibility and osteoconductivity of a cement containing beta-TCP for use in vertebroplasty.

A new composite bone cement designated "G2B1" was developed for percutaneous transpedicular vertebroplasty. G2B1 contains beta tricalcium phosphate particles and methylmethacrylate-methylacrylate copolymer as the powder components, and methylmethacrylate, urethane dimethacrylate, and tetrahydrofurfuryl methacrylate as the liquid components. Biocompatibility and osteoconductivity were evaluated using scanning electron microscopy, contact microradiography, and Giemsa surface staining 4, 8, 12, 26, and 52 weeks after implantation into rat tibiae. To evaluate osteoconductivity, affinity indices (%) were calculated. Scanning electron microscopy and contact microradiography revealed that bone contact with G2B1 was attained within 4 weeks (affinity index: 50.2 +/- 11.8 at 4 weeks) and at most of the margin within 26 weeks (affinity index: 87.4 +/- 7.2 at 26 weeks). Specifically, G2B1 contacted bone via a wide calcium-phosphate-rich layer, and its degradation started within 8 weeks, mainly in the marginal area. Giemsa surface staining showed that there was almost no inflammatory reaction around the G2B1. These results indicate that G2B1 is a biocompatible and osteoconductive bone cement.

Animals↗

PubMed2006

Differential cross section and photon-beam asymmetry for the gamma n --> K+ Sigma- reaction at E gamma = 1.5-2.4 GeV.

Differential cross sections and photon-beam asymmetries have been measured for the gamma n --> K+ Sigma- and gamma p --> K+Sigma0 reactions separately using liquid deuterium and hydrogen targets with incident linearly polarized photon beams of E gamma = 1.5-2.4 GeV at 0.6 < cos ThetacmK< 1. The cross section ratio of sigma K+ Sigma-/sigma K+ Sigma0, expected to be 2 on the basis of the isospin 1/2 exchange, is found to be close to 1. For the K+ Sigma- reaction, large positive asymmetries are observed, indicating the dominance of K* exchange. The large difference between the asymmetries for the K+ Sigma- and K+ Sigma0 reactions cannot be explained by simple theoretical considerations based on Regge model calculations.

Journal Article↗

PubMed2006

Touchdown of the Hayabusa spacecraft at the Muses Sea on Itokawa.

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

Journal Article↗

PubMed2006

Assessment of efficacy of a live oral poliovirus vaccine for virulent Sabin-like poliovirus 1 strains in Japan.

Virulent Sabin-like poliovirus (VSLP) was isolated from river and sewage waters between October 1993 and September 1995 in Toyama Prefecture, Japan (Yoshida et al., Lancet 356, 1461-1463, 2000). In this study, to assess the possibility of an epidemic of poliomyelitis caused by a VSLP in Japan under the current vaccination policy of administration of live attenuated oral poliovirus vaccine (OPV), we determined titers of serum neutralizing antibodies to poliovirus 1 (PV-1) strains Sabin (vaccine strain), Mahoney (wild-type strain) and G4-12 (VSLP) in various groups of residents of Toyama Prefecture, Japan. The seropositivity and geometric mean neutralizing antibody titers against these strains in the individuals who obtained two doses of OPV were 99.1%, 94.5% and 95.5%, respectively, and 564, 186 and 194, respectively. Although the antibody titers to G4-12 were lower compared with those to Sabin, these results indicate that the OPV vaccination policy in Japan has been effective in preventing poliomyelitis caused by VSLPs. These results also suggest that (i) an epidemic of poliomyelitis caused by a VSLP has not occurred in Japan due to herd immunity, and (ii) the possibility of reemergence of VSLPs will be prevented if sufficient herd immunity is acquired immediately after completion of the OPV vaccination in accordance with the poliomyelitis eradication program.

Adolescent↗

PubMed2006

Cyclin B1 is useful to predict occult cervical lymph node metastases in tongue carcinoma.

Cyclin B1 plays an important role in regulating the G2-M transition of the cell cycle. In this study, we evaluated the immunohistochemical expression of cyclin B1 in a series of 40 oral tongue squamous cell carcinomas and analyzed the findings in relation to both clinicopathological variables and the Ki-67 labeling index. In normal squamous epithelium, cyclin B1 was localized in the nucleus and was expressed only in several cells of the basal and parabasal layers. By contrast, in dysplastic epithelium, cyclin B1 was localized in the cytoplasm and nuclei, and the numbers of cyclin B1 positive cells increased compared with normal epithelium. In tumor tissues, cyclin B1 expression was observed mainly in the cytoplasm, and the cyclin B1 labeling index ranged from 2 to 21%, with a mean of 11%. Cyclin B1 overexpression was positively correlated with occult cervical lymph node metastases and the number of mitotic cells. In addition, there was a positive relationship between labeling indices of cyclin B1 and Ki-67. These findings indicate that cyclin B1 could be a useful prognostic marker of occult cervical lymph node metastases in tongue carcinoma.

Adult↗

PubMed2005

Subaru telescope observations of Deep Impact.

The impact cratering process on a comet is controversial but holds the key for interpreting observations of the Deep Impact collision with comet 9P/Tempel 1. Mid-infrared data from the Cooled Mid-Infrared Camera and Spectrometer (COMICS) of the Subaru Telescope indicate that the large-scale dust plume ejected by the impact contained a large mass (approximately 10(6) kilograms) of dust and formed two wings approximately +/-45 degrees from the symmetric center, both consistent with gravity as the primary control on the impact and its immediate aftermath. The dust distribution in the inner part of the plume, however, is inconsistent with a pure gravity control and implies that evaporation and expansion of volatiles accelerated dust.

Cosmic Dust↗

PubMed2005

Deep Impact: observations from a worldwide Earth-based campaign.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

Cosmic Dust↗

PubMed2005

Measurement of helicity-dependent photoabsorption cross sections on the neutron from 815 to 1825 MeV.

Helicity-dependent total photoabsorption cross sections on the deuteron have been measured for the first time at ELSA (Bonn) in the photon energy range from 815 to 1825 MeV. Circularly polarized tagged photons impinging on a longitudinally polarized LiD target have been used together with a highly efficient 4pi detector system. The data around 1 GeV are not compatible with predictions from existing multipole analyses. From the measured energy range an experimental contribution to the GDH integral on the neutron of [33.9 +/- 5.5(stat) +/- 4.5(syst)] microb is extracted.

Journal Article↗

PubMed2005

Rescue use of endovascular snare for acute basilar artery embolic occlusion resistant to balloon angioplasty and fibrinolysis therapy.

A rescue clot disruption using a basket snare is described for acute basilar artery embolic occlusion resistant to balloon angioplasty and fibrinolysis therapy. In spite of failed balloon angioplasty in conjunction with fibrinolysis, a basket-shaped snare connected to a microguide wire could be used to catch and crush the clot in the upper basilar artery. The rescue use of a snare may be effective for angioplasty-resistant acute embolic stroke.

Acute Disease↗

PubMed2005

Living-donor lobar lung transplantation for pulmonary and abdominopelvic lymphangioleiomyomatosis.

We performed emergency living-donor lobar lung transplantation (LLTx) successfully in a 24-year-old woman with end-stage pulmonary and massive abdominopelvic lymphangioleiomyomatosis (LAM). Preoperatively, her respiratory condition was critical, but abdominopelvic lesions had been well controlled with medication. No LAM patients with massive abdominopelvic lesions as in the present case have been reportedly treated by LLTx previously. The present case demonstrates that LLTx can be a therapeutic option for end-stage pulmonary LAM with massive abdominopelvic involvement.

Adult↗

PubMed2005

[Successful implantation of a metal coronary angioplasty stent for bronchomalacia of the right tracheal bronchus associated with right isomerism complex in an early infant].

One-month-old boy had severe emphysema of the right upper lobe due to the stenotic tracheal bronchus compressed between the distorted right patent ductus arteriosus (PDA) and the right aortic arch associated with right isomerism complex. He underwent a left modified Blalock-Taussig shunt and a division of the PDA on cardiopulmonary bypass. Extracorporeal lung support (ECLS) was introduced because of severe hypoxemia caused by remaining bronchomalacia of the tracheal bronchus. On postoperative day 3, a metal coronary angioplasty stent was implanted at the stenotic lesion under fluoroscopic and bronchoscopic guidance. He was successfully weaned from ECLS and then respirator after the implantation. This simple stenting procedure might be an effective alternate in the treatment of bronchomalacia or bronchial stenosis in early infancy.

Angioplasty↗

PubMed2004

Nanofilm allotrope and phase transformation of ultrathin Bi film on Si(111)-7x7.

Our scanning tunneling microscopy and electron diffraction experiments revealed that a new two-dimensional allotrope of Bi forms on the Si(111)-7x7 surface. This pseudocubic [012]-oriented allotrope is stable up to four atomic layers at room temperature. Above this critical thickness, the entire volume of the film starts to transform into a bulk single-crystal (001) phase, as the bulk contribution in the cohesion becomes dominant. Based on ab initio calculations, we propose that the new allotrope consists of black phosphorus-like puckered layers stabilized by saturating all the p(z) dangling bonds in the film.

Journal Article↗

PubMed2004

Experimental check of the Gerasimov-Drell-Hearn sum rule for 1H.

For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn). New data of the doubly polarized total cross section difference are presented in the energy range from 1.6 to 2.9 GeV. The contribution to the GDH integral from 0.2-2.9 GeV yields [254+/-5(stat)+/-12(syst)] microb with negative contributions in the Regge regime at photon energies above 2.1 GeV. This trend supports the validity of the GDH sum rule.

Journal Article↗

PubMed2004

Effective application of ET-Kyoto solution for clinical lung transplantation.

The shortage of lung donors and ischemia-reperfusion injury following transplantation have been grave problems in lung transplantation (LTx). One of the most important strategies to solve these problems is the development of effective and highly reliable methods for lung preservation. Therefore, we developed a new organ preservation solution, namely, the extracellular-type trehalose-containing Kyoto (ET-Kyoto) solution. Here we report the first experience of clinical application of ET-Kyoto solution for cadaveric LTx. The recipient was a 38-year-old man with pulmonary emphysema. The donor was a 51-year-old male current smoker with a smoking history of 62 pack-years. The ventilated donor's PaO(2) was 340 Torr (FiO(2) = 1.0). The pulmonary vasculature was flushed with ET-Kyoto solution supplemented with nitroglycerine and dibutyryl cAMP. The recipient underwent bilateral sequential LTx on cardiopulmonary bypass. The ischemic time was 544 and 613 minutes for the left and right lung, respectively. PaO(2) (FiO(2) = 1.0) was 385 Torr immediately after reperfusion. The donor lung was so large that bilateral partial resections were performed at 413 minutes (right) and 348 minutes (left) after reperfusion. On histopathologic examination of the resected transplanted lungs the structure was almost normal. Postoperatively, PaO(2) (FiO(2) = 1.0) was over 400 Torr with or maximum of 526 Torr. The clinical course was almost uneventful. In conclusion, ET-Kyoto solution may be safely applied in clinical cadaveric LTx with extended donor lungs and relatively long ischemic times. Functional and histopathological efficiency of ET-Kyoto solution was confirmed. Longer preservation times with preserved quality using ET-Kyoto solution would increase the donor pool and enable semielective LTx.

Adult↗

PubMed2004

Successful staged treatment for ruptured blister-like dissecting aneurysm of the intracranial internal carotid artery: acute GDC embolization for the blister-like aneurysm followed by proximal occlusion with extracranial-intracranial bypass in the chronic stage.

The surgical treatment of ruptured blister-like dissecting aneurysm on the internal carotid artery (ICA) is still controversial. We report a case of this disease successfully managed by a staged treatment: GDC packing into the blister-like aneurysm in the acute stage followed by proximal occlusion in the chronic stage. The merit of this staged treatment is to prevent rerupture in the acute stage and to allow the proximal occlusion in the chronic stage with or without an extracranial-intracranial bypass, after assessment of tolerance of the ICA occlusion.

Acute Disease↗