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H Aoyama

Publications and source records attributed to H Aoyama.

At least 19 recordsLinked to original sources
PubMed2000

High-speed magnetic resonance imaging for four-dimensional treatment planning of conformal radiotherapy of moving body tumors.

PURPOSE: High-speed magnetic resonance imaging (MRI) was applied to the determination of the planning target volume (PTV) of moving hepatobiliary tumors. METHODS AND MATERIALS: Three moving tumors, including two metastatic hepatic tumors and one bile duct tumor, were examined using high-speed MRI and reference fiducial markers before external radiotherapy. Patients were examined for 30 seconds under conditions of normal breathing during the examination. The coordinates of the center of the tumor contours were shown on sagittal and coronal images displayed on the monitor. RESULTS: The maximum length of movement was 10.6 +/- 7.0 mm in a craniocaudal direction; 5.2 +/- 1.8 mm in a lateral direction; and 4.6 +/- 1.6 mm in a ventrodorsal direction. When the PTV was determined using MRI at exhalation phase with a 10-mm safety margin, clinical target volume (CTV) was not covered in 19% of all images in the 3 patients. With MRI at inhalation phase with a 10-mm safety margin, CTV was not covered in 36% of all images. CONCLUSION: Four-dimensional treatment planning using high speed MRI, and integrating time and spatial information, has the potential to determine the planning target volume of moving body tumors more precisely than does conventional CT planning.

Bile Duct Neoplasms↗
PubMed2000

Four-dimensional treatment planning and fluoroscopic real-time tumor tracking radiotherapy for moving tumor.

PURPOSE: To achieve precise three-dimensional (3D) conformal radiotherapy for mobile tumors, a new radiotherapy system and its treatment planning system were developed and used for clinical practice. METHODS AND MATERIALS: We developed a linear accelerator synchronized with a fluoroscopic real-time tumor tracking system by which 3D coordinates of a 2.0-mm gold marker in the tumor can be determined every 0.03 second. The 3D relationships between the marker and the tumor at different respiratory phases are evaluated using CT image at each respiratory phase, whereby the optimum phase can be selected to synchronize with irradiation (4D treatment planning). The linac is triggered to irradiate the tumor only when the marker is located within the region of the planned coordinates relative to the isocenter. RESULTS: The coordinates of the marker were detected with an accuracy of +/- 1 mm during radiotherapy in the phantom experiment. The time delay between recognition of the marker position and the start or stop of megavoltage X-ray irradiation was 0.03 second. Fourteen patients with various tumors were treated by conformal radiotherapy with a "tight" planning target volume (PTV) margin. They were surviving without relapse or complications with a median follow-up of 6 months. CONCLUSION: Fluoroscopic real-time tumor tracking radiotherapy following 4D treatment planning was developed and shown to be feasible to improve the accuracy of the radiotherapy for mobile tumors.

Computer Systems↗
PubMed2000

Impact of respiratory movement on the computed tomographic images of small lung tumors in three-dimensional (3D) radiotherapy.

PURPOSE: Three-dimensional (3D) treatment planning has often been performed while patients breathe freely, under the assumption that the computed tomography (CT) images represent the average position of the tumor. We investigated the impact of respiratory movement on the free-breathing CT images of small lung tumors using sequential CT scanning at the same table position. METHODS: Using a preparatory free-breathing CT scan, the patient's couch was fixed at the position where each tumor showed its maximum diameter on image. For 16 tumors, over 20 sequential CT images were taken every 2 s, with a 1-s acquisition time occurring during free breathing. For each tumor, the distance between the surface of the CT table and the posterior border of the tumor was measured to determine whether the edge of the tumor was sufficiently included in the planning target volume (PTV) during normal breathing. RESULTS: In the sequential CT scanning, the tumor itself was not visible in the examination slice in 21% (75/357) of cases. There were statistically significant differences between lower lobe tumors (39.4%, 71/180) and upper lobe tumors (0%, 0/89) (p < 0.01) and between lower lobe tumors and middle lobe tumor (8.9%, 4/45) (p < 0.01) in the incidence of the disappearance of the tumor from the image. The mean difference between the maximum and minimum distances between the surface of the CT table and the posterior border of the tumor was 6.4 mm (range 2.1-24.4). CONCLUSION: Three-dimensional treatment planning for lung carcinoma would significantly underdose many lesions, especially those in the lower lobe. The excess "safety margin" might call into question any additional benefit of 3D treatment. More work is required to determine how to control respiratory movement.

Adolescent↗
PubMed2000

The role of radiotherapy in treating squamous cell carcinoma of the external auditory canal, especially in early stages of disease.

PURPOSE: Our intent was to investigate the role of radiotherapy in treating external auditory canal squamous cell carcinoma, especially in early stages of disease. MATERIALS AND METHODS: The treatment results for 20 patients treated between 1980 and 1998 were retrospectively analyzed. Radiotherapy was used as an initial treatment without surgery in eight patients and with surgery in 12 patients. The patients treated by radiotherapy alone received 65 Gy in 26 fractions over 6.5 weeks. The patients treated with radiotherapy perioperatively received 30-75 Gy in 12-30 fractions. The follow-up period for survivors including patients died of intercurrent disease ranged from 7 to 205 months (mean: 71 months). RESULTS: The 5-year survival rate calculated by the Kaplan-Meier method for all patients was 59%. According to Stell classification (Laryncol. Otol. 99 (1985) 847), the 5-year survival rates for eight patients with T1 disease and eight with T2 disease were 100 and 38%, respectively. In the eight patients with T1 disease, disease control was 100%. Local control with hearing preservation was achieved in five patients with T1 disease by radiotherapy alone. No late complications related to radiotherapy were observed. CONCLUSIONS: A precise diagnosis of the disease in terms of whether or not it has invaded the bone is important in order to predict the treatment outcome. Radiotherapy with or without surgery is the treatment of choice for patients with T1-stage disease. Surgery with radiotherapy is recommended as standard care for tumors with bony invasion.

Adult↗
PubMed2000

Inhibition of acid phosphatase isoforms purified from mature soybean (Glycine max) seeds.

The four soybean seed acid phosphatase isoforms AP1, AP2, AP3A and AP3B were competitively inhibited by phosphate, vanadate, fluoride and molybdate, using p-nitrophenylphosphate as substrate. The four isoforms were not significantly affected by compounds that can interact with SH residues or by pyridoxal phosphate. These results indicated that cysteine and lysine residues are not present in the active site of the four soybean seed acid phosphatase isoforms. The inhibition constant values for phosphate, vanadate, fluoride and molybdate at pH 5.0 were respectively: API (250, 12.8, 1.7, 0.05 microM). AP2 (800, 10, 500, 0.025 microM), AP3A (250, 24.2,250, 0.032 microM ), AP3B (2400 36.9, 750, 0.05 microM).

Acid Phosphatase↗
PubMed2000

[Analyses of work-relatedness of health problems among truck drivers by questionnaire survey].

In order to estimate occupational risk factors for health problems among truck drivers, a questionnaire survey of working conditions, job content in truck transportation, subjective symptoms and present illnesses was carried out among 541 truck transportation workers in 1997. The valid response rate was 85.7%, and 134 local truck drivers, 199 long-distance truck drivers and 71 clerical workers were analyzed. First, to examine occupational risk factors and health problems among the three groups, the authors analyzed working conditions, job content in truck transportation, subjective symptoms and present illnesses. Second, to estimate the work-relatedness of health problems among local truck drivers and long-distance truck drivers, logistic regression analyses were conducted, and odds ratios and 95% confidence intervals were computed. The prevalence rates of working factors affecting health problems of truck drivers were significantly higher than those of clerical workers in the items on irregular shift work, working environment, working posture, handling heavy materials, job stress due to overloading and long working time and limited time off. The prevalence rates for subjective symptoms (ringing in the ears, neck pain and low back pain) and present illnesses (hypertension, ulcers in the digestive tract, back injuries, whiplash injuries and hemorrhoids) among truck drivers were significantly higher than those of clerical workers. In logistic regression analyses, many work-related items except age, BMI and smoking habit showed significantly higher odds ratios for subjective symptoms and present illnesses of truck drivers. Odds ratios for hypertension, heart diseases and related subjective symptoms among local truck drivers were significantly increased by job career, twisting posture, vibration and driving stress. Odds ratios for gastro-duodenal diseases and related subjective symptoms were significantly increased by narrow working space, sleeping in the truck, driving distance, squatting posture and driving stress. Odds ratios for ringing in the ears among local truck drivers were significantly increased by job career, long working time, narrow working space, sleeping in the truck and driving stress. Odds ratios for musculo-skeletal diseases and related subjective symptoms were significantly increased by overwork, vibration, narrow working space, sitting posture and shortage of recess. Odds ratios for fatigue symptoms were significantly increased by the shortage of recess, vibration and driving stress. In order to cope with the health problems of truck drivers, it is recommended that working conditions and work loads for among truck drivers as described above be improved.

Automobile Driving↗
PubMed2000

Women's anxiety in old age and long-term care provision for the elderly.

The purpose of this study was to verify the differences in women's anxiety in old age, the expected long-term care provision, and the expected final location for terminal care for the women themselves and for their parents. In addition, we examined factors that related to their anxiety and needs. The subjects were 1,000 women of the Seikatsu Club customer cooperative association in Chiba; 539 responded to our survey. The subjects were more anxious for their parents than for themselves. They more strongly expected long-term care for their parents to be provided by their family than they expected the same for themselves. Although no differences were observed in the expected location for terminal care, most subjects expected their home to be the terminal location. Analysis by the multiple logistic regression model indicated that the following factors were significantly related to the anxiety in old age: age odds ratio [OR = 1.81], employment [OR = 2.25] for women, and planning to live with parents [OR = 2.42], housing conditions [OR = 0.56] for parents. The following factors were significantly related to the expected long-term care provision: age [OR = 2.22] for women, and age [OR = 2.15], living with parents [OR = 3.58], and employment [OR = 2.33] for parents. Age [OR = 2.14] for women, and planning to live with parents [OR = 2.09] for parents were significantly related to the expected final location of terminal care. This survey showed that women expected long-term care for their parents to be provided by their family, while many expected public long-term care services for themselves. This is the biggest difference in women's outlook on long-term care for their parents and for themselves. Multivariate analysis suggested that women aged 40 years or over, who will need long-term care in the future, tended to expect public home care services for themselves. It is virtually certain that the demand for public home care services will increase in the future.

Adult↗
PubMed2000

Helicobacter pylori infection: relationship between seroprevalence and dietary preference in a rural area.

In order to evaluate the relationship between Helicobacter pylori (H. pylori) infection and dietary preference, a cross-sectional study was performed among 626 residents in a rural area of Japan. Seropositive rates were 88.7% in males and 71.4% in females, and these increased with age for both sexes [male P < 0.05 and female P < 0.01]. The relationship between H. pylori-seropositivities and salted-food intake, after adjustment for age, demonstrated a significant result in the "almost every day" group in males with an odds ratio (OR) of 8.39 and with 95% confidence intervals (CI) of 1.02-69.30. As regards an association between seropositivities of H. pylori and levels of serum pepsinogens for the screening of chronic atrophic gastritis (low pepsinogen values used were a pepsinogen I level below 70 ng/ml and a pepsinogen I/pepsinogen II ratio below 3.0), the ORs of H. pylori-seropositivities for low pepsinogen cases were 6.32 [95% CI: 1.42-28.03] in males and 12.72 [95% CI: 4.57-35.46] in females. With regard to the relationship between low pepsinogen cases and light-colored vegetables intake, a significant low OR for the low pepsinogen cases was obtained in the "almost every meal" group in females after adjustment for age and seropositivities of H. pylori with an OR of 0.37 and with 95% CI of 0.15-0.92.

Adult↗
PubMed1999

Quantitative reevaluation of the redox active sites of crystalline bovine heart cytochrome c oxidase.

Approximately 30% of the iron contained in a bovine heart cytochrome c oxidase preparation was removed by crystallization, giving a molecular extinction coefficient 1.25-1.4 times higher than those reported thus far. Six electron equivalents provided by dithionite were required for complete reduction of the crystalline cytochrome c oxidase preparation. The fully reduced enzyme was oxidized with 4 oxidation equivalents provided by molecular oxygen, giving an absorption spectrum slightly, but significantly, different from that of the original fully oxidized form. Four electron equivalents were required for complete reduction of the O(2)-oxidized enzyme. The O(2)-oxidized form, when exposed to excess amounts of O(2), was converted to the original oxidized form which required 6 electrons for complete reduction. A slow reduction of the O(2)-oxidized form without any external reductant added indicates the existence of internal electron donors for heme irons in the enzyme. These results suggest that the 2 extra oxidation equivalents in the original oxidized form, compared with the O(2)-oxidized form, are due to a bound peroxide produced by O(2) and electrons from the internal donors, consistently with a peroxide at the O(2) reduction site in the crystal structure of the enzyme (Yoshikawa, S., Shinzawa-Itoh, K. , Nakashima, R., Yaono, R., Yamashita, E., Inoue, N., Yao, M., Fei, M. J., Peters Libeu, C., Mizushima, T., Yamaguchi, H., Tomizaki, T., and Tsukihara, T. (1998) Science 280, 1723-1729).

Animals↗
PubMed1999

In situ-gelling gellan formulations as vehicles for oral drug delivery.

Gels formed in situ following oral administration of 1% (w/v) aqueous solutions of gellan to rats and rabbits were evaluated as sustained-release vehicles. The formulation contained calcium ions in complexed form, the release of which in the acidic environment of the stomach caused gelation of the gellan gum. The in vitro release of theophylline from the rigid gellan gels followed root-time kinetics over a period of 6 h. Plasma levels of theophylline after oral administration of gellan solutions and a commercial oral sustained-release liquid dosage form containing an identical drug concentration were compared in both rats and rabbits. Bioavailability of theophylline from gellan gels formed by in situ gelation in the animal stomach was increased by four-fivefold in rats and threefold in rabbits compared with that from the commercial oral formulation. There was no significant difference in the mean residence times of theophylline when administered by these two vehicles.

Administration, Oral↗
PubMed1999

Isolation and partial characterization of an extracellular low-molecular mass component with high phenoloxidase activity from Thermoascus aurantiacus.

An extracellular low-molecular mass component (LMMC) with catalytic properties was isolated from liquid cultures containing wheat bran of ascomycete thermophilic Thermoascus aurantiacus. The partially purified LMMC showed very high activity with typical phenoloxidase substrates in the absence of hydrogen peroxide at acidic pH (2.8). However, in this pH range, the phenoloxidase (PO) activity was quickly lost. The LMMC showed a high optimum temperature (80 degrees C) and an elevated thermostability. The molecular mass of the component estimated by gel filtration chromatography was 530 Da. IR and 1H- and 13C-NMR spectra indicated the presence of hydroxamic acid moiety. Qualitative determination of metal ions by several techniques revealed the presence of mainly iron associated with this structure. Iron may be the responsible for the ability for catalyze oxidation reactions, such as o-dianisidine oxidation, by the LMMC. These results suggested the existence of a hydroxamate-type metal-binding component, most likely hydroxamate siderophore. In addition, the chrome azurol S (CAS) universal assay for noncomplexed siderophores detection revealed the production of these compounds by T.aurantiacus in solid and liquid media.

Ascomycota↗
PubMed1999

Structure analysis of bovine heart cytochrome c oxidase at 2.8 A resolution.

The crystal structure of bovine heart cytochrome c oxidase has been determined at 2.8 A resolution by the multiple isomorphous replacement (MIR) method with three heavy-atom derivatives. An asymmetric unit of the crystal has a molecular weight of 422 kDa. Eight heavy atoms as main sites of a CH3HgCl derivative were clearly located by solving the difference Patterson function. The electron density obtained by the MIR method was refined by density modification, consisting of solvent flattening, histogram matching and non-crystallographic symmetry averaging. The enzyme exhibits a dimeric structure in the crystal. Out of 3606 amino-acid residues in 26 subunits in the dimer, 3560 residues were located in the electron-density map. The structure was refined by X-PLOR. The final R factor and the free R factor were 0.199 and 0.252 at 2.8 A resolution, respectively. One monomer in the dimeric structure with a stronger packing interaction has a lower averaged temperature factor than the other, by 16 A2. The region +/-12 A from the centre of the transmembrane part is almost 100% alpha-helix, despite the glycine residue content being as high as 7.1% in the transmembrane region. The residues around haem a of animals have evolved away from those of bacteria in contrast with the residues of the haem a3. The hierarchy of the structural organization of the enzyme complex has been proposed on the basis of intersubunit interactions.

Animals↗
PubMed1999

Recurrent hepatocellular carcinoma successfully treated with radiofrequency thermal ablation.

We report a patient with hepatocellular carcinoma (HCC) who was successfully treated with radiofrequency thermal ablation (RFA). A 71-year-old man was admitted to our hospital in August 1996 with recurrence of HCC. Partial hepatic resection had been performed in January 1993 for HCC that had measured 1.3 cm in segment VIII, and subsequently he had received six sessions of percutaneous ethanol injection (PEI) for treatment of recurrence. Dynamic computed tomography (CT) performed in August 1996 showed two recurrent tumors, one measuring 3.8 cm in segment VIII adjacent to the right hepatic vein, and one measuring 2.0 cm in segment V. Three sessions of percutaneous RFA were performed. After this treatment, most of the tumor in segment VIII and all the tumor in segment V showed low density on dynamic CT, and the right hepatic vein was preserved. However, a remnant of the mass appeared near the right hepatic vein 2 months after the treatment. An additional two sessions of RFA were performed. After the end of treatment, serum alpha-fetoprotein level dropped to the normal range, and no sign of recurrence has been observed until September 1998.

Aged↗
PubMed1999

Three-dimensional movement of a liver tumor detected by high-speed magnetic resonance imaging.

OBJECTIVE: Three-dimensional (3D) movement of a spherical liver tumor during respiration was investigated with magnetic resonance imaging (MRI) using a high-speed sequence. METHODS: A marker was placed on the surface of the patient as a reference of distance. Repetition time (TR) was 7.7 ms, echo time (TE) was 4.2 ms, flip angle was 20 degrees, section thickness was 8 mm, and a 256 x 128 matrix was used. The acquisition time was 1.0 s followed by an interval of 0.5 s. The 20 tumor contours extracted during 30 s were superimposed on sagittal and coronal MR images. RESULTS: The maximum value of tumor edge location was 3.9 cm in the cranio-caudal direction, 2.3 cm in the ventro-dorsal direction, and 3.1 cm in the lateral direction. The mean length of tumor displacement observed was 2.1 cm in the cranio-caudal direction, 0.8 cm in the ventro-dorsal and 0.9 cm in the left-right direction, respectively. The locus of the center of the tumor contour in the sagittal cross section was inclined at 23 degrees and in the coronal cross section was inclined at 18 degrees to the cranio-caudal axis of body. CONCLUSION: In conclusion, 3D movement of a spherical liver tumor was detected using rapid MRI sequential examinations. Magnetic resonance imaging has a potential to improve the accuracy of the planning target volume of a liver tumor.

Humans↗
PubMed1999

Determination of linezolid in plasma by reversed-phase high-performance liquid chromatography.

An HPLC-UV method was developed for assay of linezolid in dog, rat, mouse, and rabbit plasma. Linezolid and the internal standard were extracted on a solid phase cartridge (SPE) and separated on a reversed-phase column (C8, 4.6x150 mm, 5 microm) with 20% acetonitrile in water as mobile phase. The SPE quantitatively recovered linezolid and the internal standard from plasma samples. The chromatographic peak height ratio or peak area ratio based on UV absorbency at 251 nm was used for quantitative analysis. The assay procedures were simple and the assay was specific and had adequate precision and accuracy. Calibration standards with concentrations over the range of 0.01 20 microg/ml were validated for routine sample analysis to support the pharmacokinetic and toxicology studies with linezolid in dog, rat, mouse, and rabbit. Analysis of quality control samples showed the coefficients of variation were usually <10% and the measured and theoretical concentrations differed by <10% in most assays. Linezolid in the plasma samples was stable when stored at below -20 degrees C for at least 63 days, at room temperature (22-23 degrees C) for up to 24 h, and after three freeze-thaw cycles. This HPLC method has been successfully used in multiple laboratories to assay plasma samples from pharmacokinetic and toxicology studies with linezolid in the animal species.

Acetamides↗
PubMed1999

A phase I/II study of continuous intra-arterial chemotherapy using an implantable reservoir for the treatment of liver metastases from breast cancer: a Japan Clinical Oncology Group (JCOG) study 9113. JCOG Breast Cancer Study Group.

BACKGROUND: Liver metastasis from breast cancer has a poor prognosis. While there are some reports of good response rates of hepatic metastasis from breast cancer by hepatic intra-arterial infusion chemotherapy, no phase I study including pharmacokinetic analysis has been reported. We performed a phase I/II study of intra-arterial infusion chemotherapy using adriamycin and 5-fluorouracil to find the maximum tolerated dose and response rate in patients with advanced or recurrent breast cancer. METHODS: A hepatic arterial catheter with an access port was inserted into the proper hepatic artery. Patients received 30 mg/m2 adriamycin on days 1 and 8 and 100 mg/m2 5-fluorouracil at level 1, 200 mg/m2 at level 2,300 mg/m2 at level 3 and 400 mg/m2 at level 4 continuously from day 1 through day 14 every 28 days. At least two cycles were required before evaluation. Twenty-eight patients were entered into this study and 26 patients were evaluable. Seventeen patients had hepatic metastasis only, although nine patients had additional metastasis to other sites. RESULTS: Dose-limiting toxicity of thrombocytopenia and neurotoxicity occurred at level 4. Leukocytopenia (ECOG grade 3-4) was observed in five (19%), thrombocytopenia in three (12%) and anemia in two (8%) patients. There were 11 catheter-related complications which were not dose dependent. Seven out of 13 evaluable patients (54%) responded at level 3. The median duration of response was 5.8 months (range, 1-23+) and median survival was 25.3 months (range, 6.2-54.7+). CONCLUSION: Hepatic arterial infusion therapy appears to be safe and effective but catheter-related complications must be overcome before starting a phase III trial.

Adolescent↗