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T Satoh

Publications and source records attributed to T Satoh.

At least 1,405 records · Page 78Linked to original sources
PubMedDate not supplied

Implantable helical coil microwave antenna for interstitial hyperthermia.

An implantable helical coil microwave antenna has been developed for improved localization and control of interstitial hyperthermia for deep-seated tumours. A helical coil structure was employed as an extension of the inner conductor at the terminal portion of a miniature semi-rigid coaxial cable. The antennas were constructed with three different connection configurations of the helical coil to the feedline, and with several coil turn densities during the optimization of heating characteristics. In order to compare relative antenna heating performance, a set of quantitative parameters was introduced. Power deposition profiles of 2450 MHz helical coil antennas were studied in both phantom models and muscle tissue in vivo, and compared to those of commonly used dipole antennas. Optimal antenna performance was obtained with a 10-turn per 1 cm helical coil connected to the inner conductor at the tip and separated from the outer conductor by a 0.1 cm gap (HCS-10). These antennas produced a well-localized heating pattern with a sharp falloff of temperature in both directions axially from the coil element. For half-wavelength insertion depths, the effective heating length (50 per cent of maximum SAR) of HCS-10 antennas matched that of standard dipole antennas, but was shifted down towards the tip. For shorter and deeper antenna insertion depths the HCS-10 heating pattern remained similarly localized to the region surrounding the helical coil with minimal cold zone at the tip. In contrast, the dipole antenna heating pattern changed significantly depending on insertion depth, with an unavoidable 0.2-0.7 cm cold region at the antenna tip and elevated surface temperatures for short insertion depths.

Animals↗
PubMedDate not supplied

Comparative thermal dosimetry of interstitial microwave and radiofrequency-LCF hyperthermia.

Steady-state temperature distributions induced by commercial radiofrequency localized current field (RF-LCF) and microwave (MW) interstitial heating systems were compared in dog thigh muscle in vivo using repeated 15-min heating experiments in the same implant site. Control experiments consisting of up to nine successive, identical heat trials with either modality verified that induced temperature distributions could be duplicated reliably. For all comparative dosimetry experiments a square array of parallel heat sources and thermometry probes was inserted percutaneously through a 5 mm grid Plexiglas template to a depth of 7.0-8.0 cm. Metal trocar electrodes were left at the corners of square arrays for two or three successive RF-LCF heat trials. After the metal trocars were removed, two or three more heat trials were performed using dipole microwave antennas in Teflon catheters at the same four positions. The three-dimensional temperature distributions within the array boundaries were characterized by mapping up to 11 fibre optic temperature probes in 1 cm increments during the steady-state plateau of each trial. The distributions were analysed quantitatively in terms of the percentage of measured points which achieved at least 50 per cent of the maximum array temperature increase above baseline (delta Tmax). Results showed that the RF-LCF technique heated more uniformly with depth along the bare metal electrodes and more consistently within the array boundaries than the microwave dipole antennas. For all array spacings studied (1.0-3.5 cm), the RF electrodes heated approximately 10-20 per cent more of the array volume to greater than 50 per cent of delta Tmax.

Animals↗
PubMedDate not supplied

Cerebral blood flow response to the tissue temperature in tumour and brain tissues.

The response of regional-cerebral blood flow (rCBF) to change in the tissue temperature was studied using normal and tumour-bearing monkeys. The local brain was selectively heated by the external microwave irradiation, while the body was kept hypothermic (30.1 +/- 0.1 degrees C, mean +/- standard error) by immersion in a cold water bath. The rCBF in brain and/or tumour tissues was sequentially measured by inhalation hydrogen clearance method. In the normal animal study (n = 7), rCBF changed in response to the tissue temperatures over a range of 29.4-40.7 degrees C with a constant rate 15.2% per degree Celsius change. Similarly, rCBF in the tumour-bearing animals (n = 7) changed proportionately with change in the tissue temperatures over a range of 28.4-42.5 degrees C in tumour and 27.6-41.8 degrees C in brain tissue. The rate in rCBF change per degree Celsius was 6.5% for tumour, which was significantly smaller than that for brain tissue (13.5%) (P less than 0.01). These results indicated that rCBF can be controlled by the defined application of selective heating with temperatures ranging from shallow hypothermia to modest hyperthermia. Vascular response to temperatures in the tumour and brain tissues may play a significant role in the application of heat to brain tumour treatment.

Animals↗
PubMedDate not supplied

Normal brain response after interstitial microwave hyperthermia.

The effects of interstitial hyperthermia were assessed in the normal brain after a single 30 min treatment using 2450 MHz microwaves. A single helical coil microwave antenna was inserted into the frontal white matter and reference temperatures of 40, 41, 42, 43 and 44 degrees C maintained for 30 min along a temperature sensing probe 5 mm away and parallel to the antenna. The extent of hyperthermia damage was quantified weekly for 6 weeks using computed tomography (CT), and changes in regional cerebral blood flow (rCBF), tissue vascularity and mean transit time were determined using ultrafast CT. Qualitative histopathological analysis was carried out on tissues at various times after heating. Heat lesions were radiographically characterized by rapid development and resolution and consisted of an area of focal low density surrounded by a ring of contrast enhancement. Histologically, the focus of low density corresponded to regions of tissue necrosis, whereas the ring enhancement showed local reactive changes, including endothelial cell proliferation and infiltration with macrophages. Tissue necrosis occurred at temperatures greater than 43.9 +/- 1.5 degrees C (mean +/- standard deviation), and volumes of necrosis and ring enhancement were at a maximum 1 week following treatment. Relative to the contralateral, unheated hemisphere, rCBF in the heated brain appeared to be reduced for the first 3 weeks after treatment but approached normal by week 4. The mean transit time of blood was increased for weeks 1-3 compared to the untreated hemisphere, and tissue vascularity reached a maximum, 3 weeks after treatment. The rapid CT changes together with ultrafast CT and histopathological findings suggest that focal heat lesions in the brain stimulate a significant and rapid vascular response.

Animals↗
PubMedDate not supplied

Induction of apoptosis by Acanthopanax senticosus HARMS and its component, sesamin in human stomach cancer KATO III cells.

Antitumor effect of the stem bark of Acanthopanax senticosus HARMS (ASH) from Hokkaido (Japanese name: Ezoukogi) on human stomach cancer KATO III cells was investigated. The extract of the stem bark of ASH prepared with hot water was dissolved in distilled water and used for the assay of antitumor effect on the KATO III cells. The exposure of KATO III cells to ASH led to both growth inhibition and induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with ASH. The fragmentation by ASH of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. We have investigated which component in ASH is effective on the induction of apoptosis. Among chlorogenic acid, syringaresinol di-o-beta-D glucoside, syringin, and sesamin, components of the n-butanol extract prepared from ASH, sesamin suppressed the growth and induced apoptosis in the cells. These findings suggest that growth inhibition by ASH results from the apoptosis induced by sesamin, a component of ASH.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

Clinical significance of p53, MDM2 and bcl-2 expression in transitional cell carcinoma of the bladder.

We investigated the prognostic and predictive relevance of p53, MDM2, and bcl-2 protein expression in patients with transitional cell carcinoma (TCC) of the bladder. The expression of p53, MDM2 and bcl-2 protein was studied by immunohistochemical methods in paraffin-embedded specimens from 119 patients whose clinicopathologic data confirmed TCC of the bladder. Multivariate analyses of prognostic factors were performed, and correlations with classical clinicopathologic parameters were examined. Sixty-one, 12, and 17% of cases were considered positive for expression of p53, MDM2 and bcl-2, respectively. p53 expression correlated with stage (p=0.0209), but not MDM2 and bcl-2 with any clinicopathologic parameters. In Cox's regression analysis, staging demonstrated a statistically worse prognosis (hazard ratio 1.636; p=0.0059) while bcl-2 (hazard ratio 0.179; p=0.0474) expression showed favorable prognosis in stage T2-4 invasive TCC of the bladder. Co-expression with p53/MDM2 (hazard ratio 0.367; p=0.0401) and p53/bcl-2 (hazard ratio 3.487; p=0.0111) overexpression were associated with favorable and unfavorable prognosis in stage T2-4 invasive TCC of the bladder, respectively. Our results indicate that staging is the most useful parameter to predict clinical outcome in patients with TCC of the bladder. Determinations of bcl-2 and co-expression p53/MDM2 and p53/bcl-2 may be useful for predicting tumor behavior and prognosis in stage T2-4 invasive type TCC of the bladder.

Adult↗
PubMedDate not supplied

Two cases of osteosarcoma occurring as second malignancy of childhood cancer.

We report on two patients in whom osteosarcoma occurred as second malignancy of childhood cancer. One patient had a malignant teratoma and the other adrenocortical carcinoma as the primary cancer. The emergence of cancer in cured cases and long-term survival cases of childhood cancer may result in an increase in the number of osteosarcomas seen in adolescence occurring as second malignancy. Anti-cancer drugs in large does were used for the treatment of a malignant teratoma in the former. These anti-cancer drugs may be involved in the occurrence of the second malignancy. In the latter, the patient has the germ-line mutation of p53 tumor suppressor gene, so genetic factors are presumably related to the occurrence of the second malignancy.

Adolescent↗
PubMedDate not supplied

Organophosphates and their impact on the global environment.

Serious intoxications and incidences due to misuse of organophosphorus insecticides (OP) have been reported for over three decades. In this meeting I am talking about the following three topics. (1) Epidemiological studies on the use of OP in Japan, Taiwan and Thailand. The National Research Institute of Police Science (NRIPS) in Japan has published the annual report of the epidemiological studies on the criminal and suicide events. The numbers of the incidence of pesticides are approximately 22%-30% of the total incidences, during 1991 and 1996. The incidence of pesticides has been gradually reduced for past six years. This seems to be influenced by the decrease of the incidences of paraquat having extremely high toxicity. According to the epidemiological data in the National Poison Center in Taiwan, unlike the prevalence of drug poisoning exposures in most western countries, pesticides poisoning exposures are numerous in Taiwan. The number of pesticide intoxication cases is 6,872 out of 23,436 of total case numbers of various intoxications during the 1985 and 1997. The fatality rate is much higher in Taiwan than in most western countries, with 5.65% of all poisoning exposures resulted in death. Paraquot is the leading cause of death in Taiwan. The ratio of death to total OP intoxication cases is 11.5% including accidental exposure and suicide. According to the report of the Division of Epidemiology, Ministry of Public Health, Thailand during the 1990-1995, the overall morbidity due to poisoning was 30 per 100,000 population with 300 deaths per year. The morbidity rate of reported pesticide poisoning in the whole country was 10 per 100,000 population. (2) Sarin victims in Tokyo. On March 20, 1995, a terrorist attack using sarin (isopropylmethylphosphonofluoridate) occurred on the Tokyo subway. Many people inhaled the sarin gas and collapsed in the train. Eventually, 12 people died and over 5,000 were injured. The results of the forensic studies showed that methylphosphonic acid, the hydrolysis product of sarin, bound to AChE in the cerebellums of the victims was separated and identified using GCMS. (3) A sensitive and rapid biomarker of OP-poisoning. Beta-glucuronidase (beta-G) is loosely bound to egasyn which is one of carboxylesterase isozymes in the liver microsomes. The oxon formed from OP in the liver microsomes is covalently bound to egasyn and causes the cleavage of the egasyn-glucuronidase complex, leading to the release of beta-G into the blood. In fact, plasma beta-G activities is a much more sensitive and rapid biomarker than the blood cholinesterase inhibition. In conclusion, OPs cause serious toxicity in both acute and chronic exposures. The epidemiological data in Taiwan and Thailand show that paraquat intoxication cause the most serious irreversible damage in the patients. In 1995, terrorists attack using sarin which is one of the most toxic OP, on the Tokyo subway, and 12 people died. This is an example of the acute intoxication of OP and some people have been still in hospitalized. Recently, the present authors have reported that the plasma beta-G activity is a novel biomarker of OP intoxication. The plasma beta-G is rapidly and significantly increased after OP exposure, and this is a much more sensitive to OP intoxication than ChE inhibition.

Environment↗
PubMedDate not supplied

Synergistic cytotoxic action of vitamin C and vitamin K3.

We investigated the combination effect of sodium ascorbate (vitamin C) and menadione (vitamin K3) on the viability of various cultured cells. Human oral squamous cell carcinoma (HSC-2, HSC-3) and human promyelocytic leukemia (HL-60) cells were more sensitive to these vitamins as compared to normal cells (human gingival fibroblast HGF, human periodontal ligament fibroblast HPLF, human pulp cell HPC). The combination of vitamin C and vitamin K3 produced synergistic cytotoxicity against all these 6 cell lines. Treatment with vitamin C or vitamin K3, or their combination, induced internucleosomal DNA fragmentation only in HL-60 cells, but not in the oral tumor cell lines (HSC-2, HSC-3, HSG). ESR spectroscopy showed that vitamins C and K3 produce radicals under alkaline conditions and that the combination of these two vitamins synergistically enhanced their respective radical intensities.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

A new technique of laparoscopic surgery for rectal disease.

Laparoscopic rectal surgery is a technique that has to be done in a narrow space: the pelvis. If an immoderate operation is performed with a difficult view, for example in female where the field is disturbed by uterus, it is possible to produce organ trauma or an unexpected bleeding. Taking these problems in mind, we performed laparoscopic surgery in 44 cases of rectal disease with several techniques which we have invented. In these cases either the uterus or the rectum was retracted in the narrow space, and if an anterior resection was to be done, the tape was tied tightly around the rectum below the tumor to avoid touching the tumor and leaving adequate vascular irrigation to the remnant rectum. With the use of our techniques, we did not have female intestinal injury or unexpected bleeding. In addition laparoscopic anterior resection of rectum did not cause any intestinal injury, or unexpected bleeding or anastomotic leakage; also we did not have any local tumor recurrence. It is our belief that these techniques can decrease complications that traumatize the grasping intestine with intestinal forceps and prevent implantation in the anastomosis. This technical report validate that our technique modifications for rectal laparoscopic surgery are useful when a surgeon has to work in a narrow space.

Blood Loss, Surgical↗
PubMedDate not supplied

Successful treatment of recurrent intracardiac thrombus in Behçet's disease with immunosuppressive therapy.

Behçet's disease (BD) is a chronic multisystem inflammatory disorder characterized by recurrent oral and genital ulcers, skin eruptions and uveitis. Neurological, gastrointestinal, and musculoskeletal systems are also involved. Although venous and arterial vasculitis occur in up to one-third of patients, intracardiac thrombus is a very rare complication. We herein report the case of a 46-year-old man with BD who presented with a large right atrial thrombus. Within a month after surgical removal, the thrombus recurred and was successfully treated with immunosuppressants that included prednisolone and cyclophosphamide.

Behcet Syndrome↗
PubMedDate not supplied

Experimental study on the electrophysiological effects of the combination of the antiarrhythmic drugs aprindine and verapamil.

The acute electrophysiological effects of the antiarrhythmic drugs aprindine and verapamil, injected intravenously either alone or in combination, were studied in 14 dogs during invasive electrophysiology. The AH and HV intervals during sinus rhythm were significantly prolonged, especially in the aprindine and the aprindine plus verapamil groups. The cycle lengths of the antegrade and retrograde atrio-ventricular block were most prolonged in the combination group. The effective refractory period and the functional refractory period of the atrial tissue, as well as the functional refractory period of the atrio-ventricular node, the effective refractory period of ventricular tissue and the ventriculo-atrial conduction system were most prolonged when the combination of the agents was given. The effective refractory period of the atrio-ventricular node was prolonged in the groups receiving verapamil and verapamil plus aprindine. There was no significant difference in the serum concentration of each agent given alone or in combination. These results suggest that the efficacy of the combination of verapamil and aprindine may be due to additive or synergistic effects of these antiarrhythmic agents.

Animals↗
PubMedDate not supplied

Pharmacological studies of lappaconitine: supraspinal-spinal interaction in antinociception.

Changes in lappaconitine levels in blood, brain and spinal cord following subcutaneous (s.c.) injection were correlated with the analgesic activity at intervals up to 90 minutes after injection. In the mouse, intracerebroventricular (i.c.v.) and intrathecal (i.t.) injections of amounts corresponding to ED50 values in the tail pinch method (i.c.v.: 2333 ng/mouse; i.t.: 1127 ng/mouse) gave peak lappaconitine levels of 1300 ng/g brain and 761 ng/g spinal cord, respectively. However, injection of lappaconitine at ED50 by the s.c. route (7 mg/kg) gave lower peak lappaconitine levels of 320 ng/g brain and 214 ng/g spinal cord. The responses to i.c.v., i.t. and combined i.c.v. plus i.t. administration of lappaconitine were evaluated by the determination of ED50 values, which were plotted as an isobologram. The experimental point is not significantly different from the theoretical additive ED50 point. When a dose equal to the experimental additive ED50 value (i.c.v., i.t. = 620, 413 ng/mouse) was injected, peak lappaconitine levels reached 344 ng/g brain and 241 ng/g spinal cord. Thus, the equianalgesic doses of lappaconitine (ED50 by the s.c. route and additive ED50 by the i.c.v. plus i.t. route) gave closely similar concentrations of the drug in brain and spinal cord. These results indicate that a simultaneous action of lappaconitine on supraspinal and spinal sites is likely to be important for the analgesia produced by systemically administered lappaconitine.

Aconitine↗
PubMedDate not supplied

Identification of CSF fistulas by radionuclide counting.

A radionuclide counting method, performed with the patient prone and the neck flexed, was used successfully to diagnose CSF rhinorrhea in two patients. A normal radionuclide ratio (radionuclide counts in pledget/radionuclide counts in 1-ml blood sample) was obtained in 11 normal control subjects. Significance was determined to be a ratio greater than 0.37. Use of radionuclide counting method of determining CSF rhinorrhea is recommended when other methods have failed to locate a site of leakage or when posttraumatic meningitis suggests subclinical CSF rhinorrhea.

Adult↗
PubMedDate not supplied

Preliminary profiles of 13,14-dihydroprostaglandin F2 alpha synthetase catalyzing conversion of 13,14-dihydro-15-ketoprostaglandin F2 alpha to 13,14-dihydroprostaglandin F2 alpha in rat ovary.

In the rat ovary 13,14-dihydroprostaglandin F2 alpha (13,14H2-PGF2 alpha) synthetase required NADPH much more than NADH as a co-factor. 13,14H2-PGF2 alpha synthetase activity was NADPH concentration-dependent and was significantly inhibited by NADP, in the presence of NADPH, by indomethacin and by oxidized glutathione.

Animals↗
PubMedDate not supplied

Squamous cell papilloma of the esophagus in a child.

The case of a 17 month-old girl with an esophageal squamous cell papilloma is presented. There was a previous history of intermittent hematemesis and vomiting. The tumors were located in the lower esophagus and were removed operatively. Our patient is the youngest case reported so far.

Esophageal Neoplasms↗
PubMedDate not supplied

[Severe and fatal non-A non-B hepatitis in 4 young and children].

Four cases on non-A, non-B acute hepatitis have been observed in infants of the same family. No evidence of hepatitis A or B (HBs-Ag, anti-HBs antibodies, HBe-Ag, anti-HBe and anti-HBc antibodies) could be detected in sera. Virological investigations showed no evidence of cytomegalovirus, Epstein-Barr virus, infection, etc. The two younger infants developed disseminated intravascular coagulation and died. The other two recovered without sequelae.

Antibodies, Viral↗