Naoya Murakami - Academia.edu (original) (raw)

Papers by Naoya Murakami

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, Jan 24, 2015

We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi... more We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi-fractionated high-dose-rate brachytherapy (HDRBT) for cervical cancer using a novel surface-based non-rigid deformable registration. As the number of consecutive HDRBT fractions increased, simple addition of dose-volume histogram parameters significantly overestimated the dose, compared with distribution-based dose addition.

Journal of Advanced Oxidation Technologies

This article reports on an exploratory statistical analysis of the photocatalytic activity of tit... more This article reports on an exploratory statistical analysis of the photocatalytic activity of titanium(IV) oxide (TiO2; titania) using forty commercially available titania samples. Five photocatalytic reactions were examined as test reactions for the evaluation of photocatalytic activity of the samples: oxygen liberation along with silver deposition, methanol dehydrogenation, acetic acid decomposition, acetaldehyde decomposition and synthesis of pipecolinic acid from L-lysine. Six structural and physical properties of the samples were measured: specific surface area (BET), density of defective sites (DEF), primary particle size (PPS), secondary particle size (SPS) and existence of anatase (ANA) and rutile (RUT) phases. Correlations of photocatalytic activities for the five kinds of reactions with structural and physical properties of 35 (out of 40) titania samples were obtained, and photocatalytic activities were empirically reproduced by a linear combination of six properties with ...

International Journal of Photoenergy, 2008

S-or N-doping of TiO 2 powder having an anatase or rutile phase extended the photocatalytic activ... more S-or N-doping of TiO 2 powder having an anatase or rutile phase extended the photocatalytic activity for water oxidation and reduction under UV light and visible light irradiation. For the reduction of water, anatase-doped TiO 2 showed higher level of activity than that of doped TiO 2 having a rutile phase using ethanol as an electron donor. Furthermore, the activity level of S-doped TiO 2 for hydrogen evolution was higher than that of N-doped TiO 2 photocatalysts under visible light. Photocatalytic oxidation of water on doped TiO 2 having a rutile phase proceeded with fairly high efficiency when Fe 3+ ions were used as electron acceptors compared to that on doped TiO 2 having an anatase phase. In addition, water splitting under visible light irradiation was achieved by construction of a Z-scheme photocatalysis system employing the doped TiO 2 having anatase and rutile phases for H 2 and O 2 evolution and the I − /IO − 3 redox couple as an electron relay.

Journal of radiation research, Jan 16, 2015

Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. Outcomes of ... more Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. Outcomes of SBRT for liver tumors unsuitable for ablation or surgical resection were evaluated. A total of 79 patients treated with SBRT for primary hepatocellular carcinoma (HCC) between 2004 and 2012 in six Japanese institutions were studied retrospectively. Patients treated with SBRT preceded by trans-arterial chemoembolization were eligible. Their median age was 73 years, 76% were males, and their Child-Pugh scores were Grades A (85%) and B (11%) before SBRT. The median biologically effective dose (α/β = 10 Gy) was 96.3 Gy. The median follow-up time was 21.0 months for surviving patients. The 2-year overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival were 53%, 40% and 76%, respectively. Sex and serum PIVKA-II values were significant predictive factors for OS. Hypovascular or hypervascular types of HCC, sex and clinical stage were significant predictive fa...

The Laryngoscope, 2014

Treatment of head and neck squamous cell carcinoma (HNSCC) often requires radiotherapy, but relap... more Treatment of head and neck squamous cell carcinoma (HNSCC) often requires radiotherapy, but relapse can occur. There is, therefore, an urgent need for the identification of a predictive novel biomarker for radiosensitivity. The epithelial cell adhesion molecule (EpCAM) has been shown to promote the transformation of malignant tumors, and EpCAM may have prognostic significance, but it is not known if EpCAM determines prognosis, especially with respect to radiotherapy. Therefore, we determined the incidence of the expression of EpCAM in HNSCC and analyzed the prognostic value in patients with early-stage glottic cancer treated with radiotherapy. Retrospective analysis. All patients with HNSCCs examined in our hospital between January 2012 and February 2013 were analyzed prospectively for the expression of EpCAM. T1-2N0 glottic cancer patients who were primarily treated by radiation therapy between 1995 and 2008 were retrospectively investigated. Patients with or without local recurren...

BMC cancer, 2014

In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were ... more In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were contoured retrospectively based on CT images taken at the time of high-dose rate intracavitary brachytherapy (HDR-ICBT) and correlation between clinical outcome and dose of HR-CTV were analyzed. Our study population consists of 51 patients with cervical cancer (Stages IB-IVA) treated with 50 Gy external beam radiotherapy (EBRT) using central shield combined with 2-5 times of 6 Gy HDR-ICBT with or without weekly cisplatin. Dose calculation was based on Manchester system and prescribed dose of 6 Gy were delivered for point A. CT images taken at the time of each HDR-ICBT were reviewed and HR-CTVs were contoured. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model (α/β = 10 Gy). Three-year overall survival, Progression-free survival, and local control rate was 82.4%, 85.3% and 91.7%, respectively. Median cumulative dose of HR-CTV D90 was 65.0 Gy ...

Neurologia medico-chirurgica, 2009

Stereotactic radiosurgery is now a treatment option for meningiomas, especially for high-risk pat... more Stereotactic radiosurgery is now a treatment option for meningiomas, especially for high-risk patients such as those with skull base lesions. The clinical outcomes were retrospectively analyzed of stereotactic radiosurgery using the Leksell Gamma Knife((R)) performed for 98 patients with 106 skull base meningiomas at the University of Tokyo Hospital between June 1990 and April 2006 and followed up for more than a year. After a median follow-up period of 53.2 months (range 12.2-204.4 months), local tumor control rates were 86.9% and 78.9% at 5 years and 10 years, respectively. Tumors with volume of 4 cm(3) or smaller (97.5% vs. 76.1% at 5 years, p = 0.001) and tumors completely included within the isodose line of 14 Gy or more (97.5% vs. 67.2% at 5 years, p = 0.0006) had higher local control rates. Postoperative residual tumors treated by stereotactic radiosurgery were controlled in all 25 cases. Cranial nerve deficits were improved, stable, and deteriorated in 12, 64, and 3 patients...

Journal of radiation research, 2014

During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cas... more During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cases where there is considerable overlap between these organs and the target volume. This study was conducted to compare the three radiotherapy planning techniques of four-fields 3D conformal radiotherapy (3DCRT), half-field radiotherapy (the half-beam method) and intensity-modulated radiotherapy (IMRT) used to treat primary gastric lymphoma in which the planning target volume (PTV) had a large overlap with the left kidney. A total of 17 patients with gastric diffuse large B-cell lymphoma (DLBCL) were included. In DLBCL, immunochemotherapy (Rituximab + CHOP) was followed by radiotherapy of 40 Gy to the whole stomach and peri-gastric lymph nodes. 3DCRT, the half-field method, and IMRT were compared with respect to the dose-volume histogram (DVH) parameters and generalized equivalent uniform dose (gEUD) to the kidneys, liver and PTV. The mean dose and gEUD for 3DCRT was higher than for IMRT ...

The Journal of Physical Chemistry C, 2009

Anatase titanium(IV) oxide (TiO 2 ) particles with specific exposed crystal faces were prepared b... more Anatase titanium(IV) oxide (TiO 2 ) particles with specific exposed crystal faces were prepared by hydrothermal treatment of peroxo titanic acid (PTA) solution with polyvinyl alcohol as a shape-control reagent. Crystal phase, shape, and size of TiO 2 particles were found to be ...

The Journal of Physical Chemistry C, 2007

In situ photoabsorption properties of titanium(IV) oxide (TiO 2 ) powders under continuous ultrav... more In situ photoabsorption properties of titanium(IV) oxide (TiO 2 ) powders under continuous ultraviolet irradiation were investigated by double-beam photoacoustic (PA) spectroscopy. This PA measurement enabled observation of two kinds of ultraviolet-light-induced intermediate species appearing on various kinds of TiO 2 powder samples. Most of the samples (type 1) exhibited photoabsorption due to the production of trivalent titanium (Ti 3+ ) species, while transient absorption assigned to trapped holes or surface peroxy species was also observed for anatase samples with a relatively large specific surface area (type 2). Time-resolved measurements and analyses of the kinetics of photoinduced Ti 3+ species suggest that electrons accumulated in type-2 samples have high reactivity toward molecular oxygen compared to type-1 samples. Saturation limits of intensity of the PA signal attributed to Ti 3+ species under deaerated conditions in the presence of surface-adsorbed methanol were estimated for both types of samples, and their linear relation with density of Ti 3+ species estimated by a conventional photochemical technique was observed. This suggests that the present double-beam PA technique is an alternative feasible method for estimation of density of Ti 3+ species, which is a potential measure of density of crystalline defects. * Corresponding

The Journal of Physical Chemistry C, 2013

ABSTRACT A rhodium(III) ion (Rh3+)-modified TiO2 (Rh3+/TiO2) photocatalyst, prepared by a simple ... more ABSTRACT A rhodium(III) ion (Rh3+)-modified TiO2 (Rh3+/TiO2) photocatalyst, prepared by a simple adsorption method and exhibiting high levels of photocatalytic activity in degradation of organic compounds, was investigated by using X-ray absorption fine structure (XAFS) measurements, (photo)electrochemical measurements, double-beam photoacoustic (DB-PA) spectroscopic measurements, and photoluminescence measurements. Based on the results, the features of the Rh3+ modifier and the working mechanism of the Rh3+/TiO2 photocatalyst are discussed. XAFS measurements revealed that the Rh3+ species were highly dispersed and almost atomically isolated on TiO2. The (photo)electrochemical measurements, DB-PA spectroscopic measurements, and photoluminescence showed a unique bifunction of the Rh3+ modifier as a promoter for O2 reductions and an electron injector to the conduction band of TiO2 for response to visible light. The reasons for the Rh3+/TiO2 photocatalyst exhibiting higher levels of photocatalytic activity than those of TiO2 photocatalysts modified with other metal ions are also discussed on the basis of obtained results.

Synapse, 2002

We investigated changes in signal transduction via calcineurin (CaN) in the striatum of rats beha... more We investigated changes in signal transduction via calcineurin (CaN) in the striatum of rats behaviorally sensitized to methamphetamine (Meth). The rats were injected with Meth (4 mg/kg, s.c.) five times a week for 3 weeks and then were given a challenge dose of Meth (2 mg/kg, s.c.). Seven days after the challenge test, we determined the levels of CaN Aalpha and Abeta by Western blotting. We further immunoquantified DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, mw 32,000) and phosphothreonine-DARPP-32, which can be dephosphorylated at threonine sites by CaN. We found that both CaN Aalpha and Abeta were significantly decreased in the particulate fractions but were not changed in the soluble fractions from the striatum of Meth-sensitized rats as compared with control rats. The same findings were observed in the striatum of rats 6 h after the injection of PCP (10 mg/kg, s.c.). In the striatum of Meth-sensitized rats, phosphothreonine-DARPP-32 immunoreactivities significantly increased, but DARPP-32 immunoreactivities were not significantly different from those of the control rats. These results indicate that the activity of signal transduction via CaN is functionally decreased in the striatum of Meth-sensitized rats.

Strahlentherapie und Onkologie, 2008

Purpose: To find the factors which influence the acute increment of International Prostate Sympto... more Purpose: To find the factors which influence the acute increment of International Prostate Symptom Score (IPSS) after transperineal permanent interstitial implant (TPI) using 125 I seeds. Patients and Methods: From April 2004 through September 2006, 104 patients with nonmetastatic prostate cancer underwent TPI without external-beam irradiation. Median patient age was 70 years with a median follow-up of 13.0 months. 73 patients (70%) received neoadjuvant hormone therapy. The increment of IPSS was defined as the difference between pre-and postimplant maximal IPSS. Clinical, treatment, and dosimetric parameters evaluated included age, initial prostate-specific antigen, Gleason Score, neoadjuvant hormone therapy, initial IPSS, post-TPI prostatic volume, number of implanted seeds, prostate V 100 , V 150 , D 90 , urethral D max , and urethral D 90 . In order to further evaluate detailed urethral doses, the base and apical urethra were defined and the dosimetric parameters were calculated. Results: The IPSS peaked 3 months after TPI and returned to baseline at 12-15 months. Multivariate analysis demonstrated a statistically significant correlation of post-TPI prostatic volume, number of implanted seeds, and the dosimetric parameters of the base urethra with IPSS increment.

Radiotherapy and Oncology, 2008

Purpose: Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific cl... more Purpose: Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific clinical and pathologic features that may affect diverse organs. We analyzed our recent experience with Stage I/II MALT lymphoma presenting in the stomach and other organs to assess the outcome following radiation therapy (RT) alone.

Radiation Oncology, 2014

Background and aims: Stereotactic body radiotherapy (SBRT) is a relatively new treatment for live... more Background and aims: Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. The outcomes of SBRT for liver tumor unfit for ablation and surgical resection were evaluated. Methods: Liver tumor patients treated with SBRT in seven Japanese institutions were studied retrospectively. Patients given SBRT for liver tumor between 2004 and 2012 were collected. Patients treated with SBRT preceded by trans-arterial chemoembolization (TACE) were eligible. Seventy-nine patients with hepatocellular carcinoma (HCC) and 51 patients with metastatic liver tumor were collected. The median biologically effective dose (BED) (α/β = 10 Gy) was 96.3 Gy for patients with HCC and 105.6 Gy with metastatic liver tumor.

Radiation Oncology, 2014

Purpose of this study was to identify predictors of vaginal ulcer after CT based three-dimensiona... more Purpose of this study was to identify predictors of vaginal ulcer after CT based three-dimensional image-guided high-dose-rate interstitial brachytherapy (HDR-ISBT) for gynecologic malignancies. Records were reviewed for 44 female (14 with primary disease and 30 with recurrence) with gynecological malignancies treated with HDR-ISBT with or without external beam radiation therapy. The HDR-ISBT applicator insertion was performed with image guidance by trans-rectal ultrasound and CT. The median clinical target volume was 35.5 ml (2.4-142.1 ml) and the median delivered dose in equivalent dose in 2 Gy fractions (EQD2) for target volume D90 was 67.7 Gy (48.8-94.2 Gy, doses of external-beam radiation therapy and brachytherapy were combined). For re-irradiation patients, median EQD2 of D(2cc) for rectum and bladder, D0.5cc, D(1cc), D(2cc), D(4cc), D(6cc) and D(8cc) for vaginal wall was 91.1 Gy, 100.9 Gy, 260.3 Gy, 212.3 Gy, 170.1 Gy, 117.1 Gy, 105.2 Gy, and 94.7 Gy, respectively. For those without prior radiation therapy, median EQD2 of D(2cc) for rectum and bladder, D(0.5cc), D(1cc), D(2cc), D(4cc), D(6cc) and D(8cc) for vaginal wall was 56.3 Gy, 54.3 Gy, 147.4 Gy, 126.2 Gy, 108.0 Gy, 103.5 Gy, 94.7 Gy, and 80.7 Gy, respectively. Among five patients with vaginal ulcer, three had prior pelvic radiation therapy in their initial treatment and three consequently suffered from fistula formation. On univariate analysis, re-irradiation and vaginal wall D(2cc) in EQD2 was the clinical predictors of vaginal ulcer (p = 0.035 and p = 0.025, respectively). The ROC analysis revealed that vaginal wall D(2cc) is the best predictor of vaginal ulcer. The 2-year incidence rates of vaginal ulcer in the patients with vaginal wall D(2cc) in EQD2 equal to or less than 145 Gy and over 145 Gy were 3.7% and 23.5%, respectively, with a statistically significant difference (p = 0.026). Re-irradiation and vaginal D(2cc) is a significant predictor of vaginal ulcer after HDR-ISBT for gynecologic malignancies. Three-dimensional image-guided treatment planning should be performed to ensure adequate target coverage while minimizing vaginal D(2cc) in order to avoid vagina ulcer.

Neuropsychopharmacology, 2003

Phencyclidine (PCP) induces a psychotomimetic state that closely resembles schizophrenia. Therefo... more Phencyclidine (PCP) induces a psychotomimetic state that closely resembles schizophrenia. Therefore, PCP-treated animals can provide a model for schizophrenia. Using differential display, we identified a gene regulated by the delayed action of PCP in rat nucleus accumbens (NAcs). Sequence analysis showed that the cDNA clone obtained was identical to rat synapse-associated protein 90/postsynaptic density-95-associated protein 1 (SAPAP1). Quantitative reverse transcriptase (RT)-PCR analysis showed that SAPAP1 mRNA had increased significantly in rat NAc (P<0.0001) and hippocampus (P<0.01) 24 h after a PCP (10 mg/kg) injection as compared to the controls. Immunoquantification using an anti-SAPAP1 antibody indicated that immunoreactivity for SAPAP1 increased significantly (P&<0.05) in the NAcs of unmedicated patients with schizophrenia, as compared to the control subjects and medicated patients with schizophrenia. Our findings support the hypothesis that there is abnormal glutamatergic neurotransmission in schizophrenia and show evidence of abnormalities in the intracellular signal transduction via N-methyl-D-aspartate (NMDA) receptors.

Journal of the American Chemical Society, 2008

Tungsten oxide loaded with nanoparticulate platinum is demonstrated to exhibit high activity for ... more Tungsten oxide loaded with nanoparticulate platinum is demonstrated to exhibit high activity for the decomposition of organic compounds both in liquid and gas phases; the activity was almost comparable to that of TiO2 under UV light irradiation and much higher than that of nitrogen-doped TiO2 under visible irradiation.

Journal of Radiation Research, 2014

The influence of deviations in dwell times and source positions for 192 Ir HDR-RALS was investiga... more The influence of deviations in dwell times and source positions for 192 Ir HDR-RALS was investigated. The potential dose errors for various kinds of brachytherapy procedures were evaluated. The deviations of dwell time ΔT of a 192 Ir HDR source for the various dwell times were measured with a well-type ionization chamber. The deviations of source position ΔP were measured with two methods. One is to measure actual source position using a check ruler device. The other is to analyze peak distances from radiographic film irradiated with 20 mm gap between the dwell positions. The composite dose errors were calculated using Gaussian distribution with ΔT and ΔP as 1σ of the measurements. Dose errors depend on dwell time and distance from the point of interest to the dwell position. To evaluate the dose error in clinical practice, dwell times and point of interest distances were obtained from actual treatment plans involving cylinder, tandem-ovoid, tandem-ovoid with interstitial needles, multiple interstitial needles, and surface-mold applicators. The ΔT and ΔP were 32 ms (maximum for various dwell times) and 0.12 mm (ruler), 0.11 mm (radiographic film). The multiple interstitial needles represent the highest dose error of 2%, while the others represent less than approximately 1%. Potential dose error due to dwell time and source position deviation can depend on kinds of brachytherapy techniques. In all cases, the multiple interstitial needles is most susceptible.

Journal of Power Sources, 2006

The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been ... more The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing disc-type intermediatetemperature solid oxide fuel cells (IT-SOFCs) since 2001. Operation temperatures between 600 and 800 • C have been set as the target. These temperatures enable SOFCs to use inexpensive metallic separators for cell-stacking and are sufficiently high for steam reforming of the hydrocarbon fuel. A 1 kW-class demonstration power generation system with a module that had a steam-reforming function was developed in 2003. The third generation module and the fourth generation module were developed in 2004. The third generation module was integrated into the system for various tests including long-term stability. The fourth generation module was examined for performance evaluation. The system included an SOFC module, a dc-ac inverter, a desulfurizer, a heat-recovery unit, and an automatic control device. The long-term stability test for over 1000 h gave no decrease in stack voltage. In parallel, the long-term stability test of a single cell stack unit was continued for over 10,000 h. In addition, hot water at 90 • C was obtained by the heat-recovery unit using high temperatures off-gas from the SOFC module. The newly developed fourth generation module gave an electrical efficiency of 60% (dc/lower heating value) using town gas as a fuel at an average stack temperatures of about 750 • C. A 10 kW-class SOFC co-generation system has been under development in a New Energy and Industrial Technology Development Organization project since 2004.

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, Jan 24, 2015

We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi... more We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi-fractionated high-dose-rate brachytherapy (HDRBT) for cervical cancer using a novel surface-based non-rigid deformable registration. As the number of consecutive HDRBT fractions increased, simple addition of dose-volume histogram parameters significantly overestimated the dose, compared with distribution-based dose addition.

Journal of Advanced Oxidation Technologies

This article reports on an exploratory statistical analysis of the photocatalytic activity of tit... more This article reports on an exploratory statistical analysis of the photocatalytic activity of titanium(IV) oxide (TiO2; titania) using forty commercially available titania samples. Five photocatalytic reactions were examined as test reactions for the evaluation of photocatalytic activity of the samples: oxygen liberation along with silver deposition, methanol dehydrogenation, acetic acid decomposition, acetaldehyde decomposition and synthesis of pipecolinic acid from L-lysine. Six structural and physical properties of the samples were measured: specific surface area (BET), density of defective sites (DEF), primary particle size (PPS), secondary particle size (SPS) and existence of anatase (ANA) and rutile (RUT) phases. Correlations of photocatalytic activities for the five kinds of reactions with structural and physical properties of 35 (out of 40) titania samples were obtained, and photocatalytic activities were empirically reproduced by a linear combination of six properties with ...

International Journal of Photoenergy, 2008

S-or N-doping of TiO 2 powder having an anatase or rutile phase extended the photocatalytic activ... more S-or N-doping of TiO 2 powder having an anatase or rutile phase extended the photocatalytic activity for water oxidation and reduction under UV light and visible light irradiation. For the reduction of water, anatase-doped TiO 2 showed higher level of activity than that of doped TiO 2 having a rutile phase using ethanol as an electron donor. Furthermore, the activity level of S-doped TiO 2 for hydrogen evolution was higher than that of N-doped TiO 2 photocatalysts under visible light. Photocatalytic oxidation of water on doped TiO 2 having a rutile phase proceeded with fairly high efficiency when Fe 3+ ions were used as electron acceptors compared to that on doped TiO 2 having an anatase phase. In addition, water splitting under visible light irradiation was achieved by construction of a Z-scheme photocatalysis system employing the doped TiO 2 having anatase and rutile phases for H 2 and O 2 evolution and the I − /IO − 3 redox couple as an electron relay.

Journal of radiation research, Jan 16, 2015

Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. Outcomes of ... more Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. Outcomes of SBRT for liver tumors unsuitable for ablation or surgical resection were evaluated. A total of 79 patients treated with SBRT for primary hepatocellular carcinoma (HCC) between 2004 and 2012 in six Japanese institutions were studied retrospectively. Patients treated with SBRT preceded by trans-arterial chemoembolization were eligible. Their median age was 73 years, 76% were males, and their Child-Pugh scores were Grades A (85%) and B (11%) before SBRT. The median biologically effective dose (α/β = 10 Gy) was 96.3 Gy. The median follow-up time was 21.0 months for surviving patients. The 2-year overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival were 53%, 40% and 76%, respectively. Sex and serum PIVKA-II values were significant predictive factors for OS. Hypovascular or hypervascular types of HCC, sex and clinical stage were significant predictive fa...

The Laryngoscope, 2014

Treatment of head and neck squamous cell carcinoma (HNSCC) often requires radiotherapy, but relap... more Treatment of head and neck squamous cell carcinoma (HNSCC) often requires radiotherapy, but relapse can occur. There is, therefore, an urgent need for the identification of a predictive novel biomarker for radiosensitivity. The epithelial cell adhesion molecule (EpCAM) has been shown to promote the transformation of malignant tumors, and EpCAM may have prognostic significance, but it is not known if EpCAM determines prognosis, especially with respect to radiotherapy. Therefore, we determined the incidence of the expression of EpCAM in HNSCC and analyzed the prognostic value in patients with early-stage glottic cancer treated with radiotherapy. Retrospective analysis. All patients with HNSCCs examined in our hospital between January 2012 and February 2013 were analyzed prospectively for the expression of EpCAM. T1-2N0 glottic cancer patients who were primarily treated by radiation therapy between 1995 and 2008 were retrospectively investigated. Patients with or without local recurren...

BMC cancer, 2014

In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were ... more In this study, high risk clinical target volumes (HR-CTVs) according to GEC-ESTRO guideline were contoured retrospectively based on CT images taken at the time of high-dose rate intracavitary brachytherapy (HDR-ICBT) and correlation between clinical outcome and dose of HR-CTV were analyzed. Our study population consists of 51 patients with cervical cancer (Stages IB-IVA) treated with 50 Gy external beam radiotherapy (EBRT) using central shield combined with 2-5 times of 6 Gy HDR-ICBT with or without weekly cisplatin. Dose calculation was based on Manchester system and prescribed dose of 6 Gy were delivered for point A. CT images taken at the time of each HDR-ICBT were reviewed and HR-CTVs were contoured. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model (α/β = 10 Gy). Three-year overall survival, Progression-free survival, and local control rate was 82.4%, 85.3% and 91.7%, respectively. Median cumulative dose of HR-CTV D90 was 65.0 Gy ...

Neurologia medico-chirurgica, 2009

Stereotactic radiosurgery is now a treatment option for meningiomas, especially for high-risk pat... more Stereotactic radiosurgery is now a treatment option for meningiomas, especially for high-risk patients such as those with skull base lesions. The clinical outcomes were retrospectively analyzed of stereotactic radiosurgery using the Leksell Gamma Knife((R)) performed for 98 patients with 106 skull base meningiomas at the University of Tokyo Hospital between June 1990 and April 2006 and followed up for more than a year. After a median follow-up period of 53.2 months (range 12.2-204.4 months), local tumor control rates were 86.9% and 78.9% at 5 years and 10 years, respectively. Tumors with volume of 4 cm(3) or smaller (97.5% vs. 76.1% at 5 years, p = 0.001) and tumors completely included within the isodose line of 14 Gy or more (97.5% vs. 67.2% at 5 years, p = 0.0006) had higher local control rates. Postoperative residual tumors treated by stereotactic radiosurgery were controlled in all 25 cases. Cranial nerve deficits were improved, stable, and deteriorated in 12, 64, and 3 patients...

Journal of radiation research, 2014

During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cas... more During radiotherapy for gastric lymphoma, it is difficult to protect the liver and kidneys in cases where there is considerable overlap between these organs and the target volume. This study was conducted to compare the three radiotherapy planning techniques of four-fields 3D conformal radiotherapy (3DCRT), half-field radiotherapy (the half-beam method) and intensity-modulated radiotherapy (IMRT) used to treat primary gastric lymphoma in which the planning target volume (PTV) had a large overlap with the left kidney. A total of 17 patients with gastric diffuse large B-cell lymphoma (DLBCL) were included. In DLBCL, immunochemotherapy (Rituximab + CHOP) was followed by radiotherapy of 40 Gy to the whole stomach and peri-gastric lymph nodes. 3DCRT, the half-field method, and IMRT were compared with respect to the dose-volume histogram (DVH) parameters and generalized equivalent uniform dose (gEUD) to the kidneys, liver and PTV. The mean dose and gEUD for 3DCRT was higher than for IMRT ...

The Journal of Physical Chemistry C, 2009

Anatase titanium(IV) oxide (TiO 2 ) particles with specific exposed crystal faces were prepared b... more Anatase titanium(IV) oxide (TiO 2 ) particles with specific exposed crystal faces were prepared by hydrothermal treatment of peroxo titanic acid (PTA) solution with polyvinyl alcohol as a shape-control reagent. Crystal phase, shape, and size of TiO 2 particles were found to be ...

The Journal of Physical Chemistry C, 2007

In situ photoabsorption properties of titanium(IV) oxide (TiO 2 ) powders under continuous ultrav... more In situ photoabsorption properties of titanium(IV) oxide (TiO 2 ) powders under continuous ultraviolet irradiation were investigated by double-beam photoacoustic (PA) spectroscopy. This PA measurement enabled observation of two kinds of ultraviolet-light-induced intermediate species appearing on various kinds of TiO 2 powder samples. Most of the samples (type 1) exhibited photoabsorption due to the production of trivalent titanium (Ti 3+ ) species, while transient absorption assigned to trapped holes or surface peroxy species was also observed for anatase samples with a relatively large specific surface area (type 2). Time-resolved measurements and analyses of the kinetics of photoinduced Ti 3+ species suggest that electrons accumulated in type-2 samples have high reactivity toward molecular oxygen compared to type-1 samples. Saturation limits of intensity of the PA signal attributed to Ti 3+ species under deaerated conditions in the presence of surface-adsorbed methanol were estimated for both types of samples, and their linear relation with density of Ti 3+ species estimated by a conventional photochemical technique was observed. This suggests that the present double-beam PA technique is an alternative feasible method for estimation of density of Ti 3+ species, which is a potential measure of density of crystalline defects. * Corresponding

The Journal of Physical Chemistry C, 2013

ABSTRACT A rhodium(III) ion (Rh3+)-modified TiO2 (Rh3+/TiO2) photocatalyst, prepared by a simple ... more ABSTRACT A rhodium(III) ion (Rh3+)-modified TiO2 (Rh3+/TiO2) photocatalyst, prepared by a simple adsorption method and exhibiting high levels of photocatalytic activity in degradation of organic compounds, was investigated by using X-ray absorption fine structure (XAFS) measurements, (photo)electrochemical measurements, double-beam photoacoustic (DB-PA) spectroscopic measurements, and photoluminescence measurements. Based on the results, the features of the Rh3+ modifier and the working mechanism of the Rh3+/TiO2 photocatalyst are discussed. XAFS measurements revealed that the Rh3+ species were highly dispersed and almost atomically isolated on TiO2. The (photo)electrochemical measurements, DB-PA spectroscopic measurements, and photoluminescence showed a unique bifunction of the Rh3+ modifier as a promoter for O2 reductions and an electron injector to the conduction band of TiO2 for response to visible light. The reasons for the Rh3+/TiO2 photocatalyst exhibiting higher levels of photocatalytic activity than those of TiO2 photocatalysts modified with other metal ions are also discussed on the basis of obtained results.

Synapse, 2002

We investigated changes in signal transduction via calcineurin (CaN) in the striatum of rats beha... more We investigated changes in signal transduction via calcineurin (CaN) in the striatum of rats behaviorally sensitized to methamphetamine (Meth). The rats were injected with Meth (4 mg/kg, s.c.) five times a week for 3 weeks and then were given a challenge dose of Meth (2 mg/kg, s.c.). Seven days after the challenge test, we determined the levels of CaN Aalpha and Abeta by Western blotting. We further immunoquantified DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, mw 32,000) and phosphothreonine-DARPP-32, which can be dephosphorylated at threonine sites by CaN. We found that both CaN Aalpha and Abeta were significantly decreased in the particulate fractions but were not changed in the soluble fractions from the striatum of Meth-sensitized rats as compared with control rats. The same findings were observed in the striatum of rats 6 h after the injection of PCP (10 mg/kg, s.c.). In the striatum of Meth-sensitized rats, phosphothreonine-DARPP-32 immunoreactivities significantly increased, but DARPP-32 immunoreactivities were not significantly different from those of the control rats. These results indicate that the activity of signal transduction via CaN is functionally decreased in the striatum of Meth-sensitized rats.

Strahlentherapie und Onkologie, 2008

Purpose: To find the factors which influence the acute increment of International Prostate Sympto... more Purpose: To find the factors which influence the acute increment of International Prostate Symptom Score (IPSS) after transperineal permanent interstitial implant (TPI) using 125 I seeds. Patients and Methods: From April 2004 through September 2006, 104 patients with nonmetastatic prostate cancer underwent TPI without external-beam irradiation. Median patient age was 70 years with a median follow-up of 13.0 months. 73 patients (70%) received neoadjuvant hormone therapy. The increment of IPSS was defined as the difference between pre-and postimplant maximal IPSS. Clinical, treatment, and dosimetric parameters evaluated included age, initial prostate-specific antigen, Gleason Score, neoadjuvant hormone therapy, initial IPSS, post-TPI prostatic volume, number of implanted seeds, prostate V 100 , V 150 , D 90 , urethral D max , and urethral D 90 . In order to further evaluate detailed urethral doses, the base and apical urethra were defined and the dosimetric parameters were calculated. Results: The IPSS peaked 3 months after TPI and returned to baseline at 12-15 months. Multivariate analysis demonstrated a statistically significant correlation of post-TPI prostatic volume, number of implanted seeds, and the dosimetric parameters of the base urethra with IPSS increment.

Radiotherapy and Oncology, 2008

Purpose: Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific cl... more Purpose: Mucosa-associated lymphoid tissue (MALT) lymphoma is a distinct disease with specific clinical and pathologic features that may affect diverse organs. We analyzed our recent experience with Stage I/II MALT lymphoma presenting in the stomach and other organs to assess the outcome following radiation therapy (RT) alone.

Radiation Oncology, 2014

Background and aims: Stereotactic body radiotherapy (SBRT) is a relatively new treatment for live... more Background and aims: Stereotactic body radiotherapy (SBRT) is a relatively new treatment for liver tumor. The outcomes of SBRT for liver tumor unfit for ablation and surgical resection were evaluated. Methods: Liver tumor patients treated with SBRT in seven Japanese institutions were studied retrospectively. Patients given SBRT for liver tumor between 2004 and 2012 were collected. Patients treated with SBRT preceded by trans-arterial chemoembolization (TACE) were eligible. Seventy-nine patients with hepatocellular carcinoma (HCC) and 51 patients with metastatic liver tumor were collected. The median biologically effective dose (BED) (α/β = 10 Gy) was 96.3 Gy for patients with HCC and 105.6 Gy with metastatic liver tumor.

Radiation Oncology, 2014

Purpose of this study was to identify predictors of vaginal ulcer after CT based three-dimensiona... more Purpose of this study was to identify predictors of vaginal ulcer after CT based three-dimensional image-guided high-dose-rate interstitial brachytherapy (HDR-ISBT) for gynecologic malignancies. Records were reviewed for 44 female (14 with primary disease and 30 with recurrence) with gynecological malignancies treated with HDR-ISBT with or without external beam radiation therapy. The HDR-ISBT applicator insertion was performed with image guidance by trans-rectal ultrasound and CT. The median clinical target volume was 35.5 ml (2.4-142.1 ml) and the median delivered dose in equivalent dose in 2 Gy fractions (EQD2) for target volume D90 was 67.7 Gy (48.8-94.2 Gy, doses of external-beam radiation therapy and brachytherapy were combined). For re-irradiation patients, median EQD2 of D(2cc) for rectum and bladder, D0.5cc, D(1cc), D(2cc), D(4cc), D(6cc) and D(8cc) for vaginal wall was 91.1 Gy, 100.9 Gy, 260.3 Gy, 212.3 Gy, 170.1 Gy, 117.1 Gy, 105.2 Gy, and 94.7 Gy, respectively. For those without prior radiation therapy, median EQD2 of D(2cc) for rectum and bladder, D(0.5cc), D(1cc), D(2cc), D(4cc), D(6cc) and D(8cc) for vaginal wall was 56.3 Gy, 54.3 Gy, 147.4 Gy, 126.2 Gy, 108.0 Gy, 103.5 Gy, 94.7 Gy, and 80.7 Gy, respectively. Among five patients with vaginal ulcer, three had prior pelvic radiation therapy in their initial treatment and three consequently suffered from fistula formation. On univariate analysis, re-irradiation and vaginal wall D(2cc) in EQD2 was the clinical predictors of vaginal ulcer (p = 0.035 and p = 0.025, respectively). The ROC analysis revealed that vaginal wall D(2cc) is the best predictor of vaginal ulcer. The 2-year incidence rates of vaginal ulcer in the patients with vaginal wall D(2cc) in EQD2 equal to or less than 145 Gy and over 145 Gy were 3.7% and 23.5%, respectively, with a statistically significant difference (p = 0.026). Re-irradiation and vaginal D(2cc) is a significant predictor of vaginal ulcer after HDR-ISBT for gynecologic malignancies. Three-dimensional image-guided treatment planning should be performed to ensure adequate target coverage while minimizing vaginal D(2cc) in order to avoid vagina ulcer.

Neuropsychopharmacology, 2003

Phencyclidine (PCP) induces a psychotomimetic state that closely resembles schizophrenia. Therefo... more Phencyclidine (PCP) induces a psychotomimetic state that closely resembles schizophrenia. Therefore, PCP-treated animals can provide a model for schizophrenia. Using differential display, we identified a gene regulated by the delayed action of PCP in rat nucleus accumbens (NAcs). Sequence analysis showed that the cDNA clone obtained was identical to rat synapse-associated protein 90/postsynaptic density-95-associated protein 1 (SAPAP1). Quantitative reverse transcriptase (RT)-PCR analysis showed that SAPAP1 mRNA had increased significantly in rat NAc (P<0.0001) and hippocampus (P<0.01) 24 h after a PCP (10 mg/kg) injection as compared to the controls. Immunoquantification using an anti-SAPAP1 antibody indicated that immunoreactivity for SAPAP1 increased significantly (P&<0.05) in the NAcs of unmedicated patients with schizophrenia, as compared to the control subjects and medicated patients with schizophrenia. Our findings support the hypothesis that there is abnormal glutamatergic neurotransmission in schizophrenia and show evidence of abnormalities in the intracellular signal transduction via N-methyl-D-aspartate (NMDA) receptors.

Journal of the American Chemical Society, 2008

Tungsten oxide loaded with nanoparticulate platinum is demonstrated to exhibit high activity for ... more Tungsten oxide loaded with nanoparticulate platinum is demonstrated to exhibit high activity for the decomposition of organic compounds both in liquid and gas phases; the activity was almost comparable to that of TiO2 under UV light irradiation and much higher than that of nitrogen-doped TiO2 under visible irradiation.

Journal of Radiation Research, 2014

The influence of deviations in dwell times and source positions for 192 Ir HDR-RALS was investiga... more The influence of deviations in dwell times and source positions for 192 Ir HDR-RALS was investigated. The potential dose errors for various kinds of brachytherapy procedures were evaluated. The deviations of dwell time ΔT of a 192 Ir HDR source for the various dwell times were measured with a well-type ionization chamber. The deviations of source position ΔP were measured with two methods. One is to measure actual source position using a check ruler device. The other is to analyze peak distances from radiographic film irradiated with 20 mm gap between the dwell positions. The composite dose errors were calculated using Gaussian distribution with ΔT and ΔP as 1σ of the measurements. Dose errors depend on dwell time and distance from the point of interest to the dwell position. To evaluate the dose error in clinical practice, dwell times and point of interest distances were obtained from actual treatment plans involving cylinder, tandem-ovoid, tandem-ovoid with interstitial needles, multiple interstitial needles, and surface-mold applicators. The ΔT and ΔP were 32 ms (maximum for various dwell times) and 0.12 mm (ruler), 0.11 mm (radiographic film). The multiple interstitial needles represent the highest dose error of 2%, while the others represent less than approximately 1%. Potential dose error due to dwell time and source position deviation can depend on kinds of brachytherapy techniques. In all cases, the multiple interstitial needles is most susceptible.

Journal of Power Sources, 2006

The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been ... more The Kansai Electric Power Co., Inc. (KEPCO) and Mitsubishi Materials Corporation (MMC) have been jointly developing disc-type intermediatetemperature solid oxide fuel cells (IT-SOFCs) since 2001. Operation temperatures between 600 and 800 • C have been set as the target. These temperatures enable SOFCs to use inexpensive metallic separators for cell-stacking and are sufficiently high for steam reforming of the hydrocarbon fuel. A 1 kW-class demonstration power generation system with a module that had a steam-reforming function was developed in 2003. The third generation module and the fourth generation module were developed in 2004. The third generation module was integrated into the system for various tests including long-term stability. The fourth generation module was examined for performance evaluation. The system included an SOFC module, a dc-ac inverter, a desulfurizer, a heat-recovery unit, and an automatic control device. The long-term stability test for over 1000 h gave no decrease in stack voltage. In parallel, the long-term stability test of a single cell stack unit was continued for over 10,000 h. In addition, hot water at 90 • C was obtained by the heat-recovery unit using high temperatures off-gas from the SOFC module. The newly developed fourth generation module gave an electrical efficiency of 60% (dc/lower heating value) using town gas as a fuel at an average stack temperatures of about 750 • C. A 10 kW-class SOFC co-generation system has been under development in a New Energy and Industrial Technology Development Organization project since 2004.