Biomedical subjects

T Togawa

Publications and source records attributed to T Togawa.

At least 37 records · Page 2Linked to original sources

PubMed1999

Chronodiagnostic acquisition of recovery speed of heart rate under bathing stress.

Cycling on an ergometer is one effective means of measuring cardiovascular function while applying stress on the heart. Bathing in a hot water bath applies a low stress to the heart. The electrocardiograms of a healthy adult male (aged 35 at the start of study) were recorded while taking a hot water bath with no electrode attached to the body over a period of 2 years (376 days over a 762 day period). The recovery speed following the initial overshoot of the heart rate (HR) was observed. The bathtub was designed for the automatic acquisition of ECG data. Immediately after immersion in the tub, the HR reached a peak within 20 s and then exponentially decreased toward the lowest rate in the 120 s of bathing. The initial recovery speed of the HR from the stress of bathing had a specific rhythm in the subject. Spectrum analysis of the speed series indicated that slow recovery speed appeared in cyclic periods of approximately 1 year, 42 days and 17 days. The methodology may provide a chronodiagnostic index of an exercise test for cardiovascular function.

Adaptation, Physiological↗

PubMed1999

67Ga planar imaging with a low-energy collimator and scatter correction using the triple energy window method.

To improve the spatial resolution and contrast of 67Ga planar imaging, we used a low-energy collimator and two lower-energy windows with a triple-energy-window (TEW) scatter compensation method. The spatial resolution is better than with a medium-energy collimator, and the TEW method can correct for scattered photons and reduce the background counts. In a phantom study and a clinical study involving 44 patients, the images obtained by the proposed method were compared with the images obtained with a medium-energy collimator and three energy windows without scatter compensation (the conventional method). The spatial resolution and the counts were measured. Two nuclear medicine physicians interpreted the images and clinical usefulness was evaluated. The spatial resolution and contrast were improved by our proposed method. It enabled the detection of lesions in five locations in the clinical study. The counts were reduced but misreadings were not seen. We conclude that our proposed method shows a clinical advantage over the conventional method. It can be used easily and quickly with commercially available equipment and is useful in clinical practice.

Adult↗

PubMed1999

[Tumor imaging using 201Tl chloride and 67Ga citrate in nucleomedical surveys].

Among nucleomedical examinations for cancer, tumor imaging using 201Tl chloride and 67Ga citrate can be easily performed at almost any hospital. However, the planar images usually obtained are not sufficient to detect small tumorous lesions. For more accurate detection, tomographic images particularly single photon emission CT (SPECT) is necessary. SPECT is also indispensable in cancer diagnosis. Whether 201Tl SPECT or 67Ga SPECT is chosen depends upon tumor localization, histological type, and the final purpose of the study. 201Tl accumulates in almost all tumors, but it is not suitable for detection of abdominal lesions, because there is much physiological accumulation in the small intestine and kidney. In contrast, 67Ga does not always accumulate in adenocarcinomas. 201Tl SPECT and 67Ga SPECT are more useful in the functional imaging of cancer than is morphological tumor diagnosis. Both methods are useful in monitoring treatment effectiveness, detecting recurrent lesions after surgery and radiotherapy, and predicting the grade of malignancy of the tumor. Tumor SPECT using 201Tl chloride and/or 67Ga citrate provides clinically useful information not obtained by morphological tumor diagnosis only.

Citrates↗

PubMed1998

Fully automated health monitoring system in the home.

The aim of this study was to provide health monitoring for elderly and disabled persons at home by using fully automated signal measurement with personal identification to support daily health care and improve quality of life. We attempted to develop a home health monitoring system that did not provide any restrictions during sleep, bathing or elimination. A bedroom, bathroom, and separate toilet were built. The system consisted of monitoring devices and a computer terminal for collecting data. Data were automatically collected from monitoring devices placed in the bed, bath, and toilet and were transferred to a data terminal in the bedroom and stored for further analysis. The system was tested by a young healthy subject who stayed overnight in the rooms. Data were obtained without any trouble. The data acquisition system is now being used in experimental rooms in our laboratory and in a house located in Takaoka City, Toyama Pref. Japan. Data are being extensively collected.

Aged↗

PubMed1998

Continuous monitoring of sweating by electrical conductivity measurement.

A method of continuous monitoring of sweating was developed in which sweat was detected by changes in the conductivity of perfusing water. An ion-free solution was perfused at a constant flow rate through a chamber attached to the skin surface. The chamber was designed so that the electrodes were installed inside at the inlet and outlet, and a 14 mm3 channel was constructed at the bottom to wash out sweat. The 90% response time was 0.12 s. Attaching the chamber to the palm allowed measurements to be made with the subject seated in a comfortable environment. The sweat rate and heart rate were measured simultaneously with an air-ventilation chamber and a heart rate counter, respectively, with the subjects at rest, and under stresses such as grasping hands and doing mental arithmetic. This method yields sweat responses similar to those obtained with an air-ventilation chamber and simultaneous heart rate measurements. The main advantages of this method are faster response time and smaller observation area.

Electric Conductivity↗

PubMed1998

Automated acquisition system for routine, noninvasive monitoring of physiological data.

A fully automated, noninvasive data-acquisition system was developed to permit long-term measurement of physiological functions at home, without disturbing subjects' normal routines. The system consists of unconstrained monitors built into furnishings and structures in a home environment. An electrocardiographic (ECG) monitor in the bathtub measures heart function during bathing, a temperature monitor in the bed measures body temperature, and a weight monitor built into the toilet serves as a scale to record weight. All three monitors are connected to one computer and function with data-acquisition programs and a data format rule. The unconstrained physiological parameter monitors and fully automated measurement procedures collect data noninvasively without the subject's awareness. The system was tested for 1 week by a healthy male subject, aged 28, in laboratory-based facilities.

Activities of Daily Living↗

PubMed1998

Therapeutic effects of 5-fluorouracil microspheres on peritoneal carcinomatosis induced by Colon 26 or B-16 melanoma in mice.

The delivery formulation 5-FU-MS [5-fluorouracil (5-FU) incorporated in microspheres composed of a poly(glycolide-co-lactide) matrix] slowly releases 5-FU over 3 weeks. 5-FU-MS delivers higher concentrations of the drug to the i.p. tissues for a longer period of time with lower blood plasma concentrations than does an aqueous 5-FU solution and reduces toxicity. In this study, we evaluated the therapeutic effects of 5-FU-MS on peritoneal carcinomatosis in mice. Four days after an i.p. inoculation with Colon 26 or B-16 PC melanoma, 5-FU at 200 mg/kg was administered i.p. as 5-FU-MS or as an aqueous solution of 5-FU. 5-FU-MS extended the survival of mice bearing Colon 26 or B-16 PC melanoma significantly better than the equivalent dose of aqueous 5-FU solution.

Animals↗

PubMed1998

Fully automated health monitoring at home.

The aim of this study was to provide adequate home health monitoring for the elderly at home using fully automated signal measurement with personal identification to support daily health care and to improve quality of life. We attempted to develop a home health monitoring system that did not provide any restrictions during sleep, bathing and excretion. A new room including bath and toilet was constructed. The system consisted of monitoring devices and a computer terminal for collecting data. The data were automatically obtained from monitoring devices situated at the bed, bath and toilet and were transferred to a data terminal and stored for further analysis. Where subjects live with their spouse or family, personal identification is required to store data individually. For the bathtub data, personal identification was performed using ECG data. Sampled data were reduced by wavelet transform and distinguished by a neural network. The data acquisition system is now underway and data are being extensively collected.

Aged↗

PubMed1998

Home health monitoring.

Due to the general aging of society, increasing national medical expenditures are becoming a serious problem. It is thus highly desirable to reduce the need for medical services by maintaining the population in good health. Intensive monitoring of health parameters will become a necessary means for attaining good health at all times. Technology for health monitoring, however, is only recently being developed. A concept of home health monitoring is proposed by which health parameters are automatically monitored at home without disturbing daily activities. There are many attempts being made to realize this concept. This article reviews these attempts at developing home health monitoring techniques, which include monitoring during sleep, via the bath tub or toilet seat, as well as during daily activities. Preliminary studies show that home health monitoring can be achieved even by means of simple sensors and instruments. There are also many possible applications for advanced technologies. Potential future technologies for home health monitoring include automatic blood pressure measurement via the toilet seat, automatic blood sampling with a device mimicking a mosquito, and artificial noses for detecting smells.

Activities of Daily Living↗

PubMed1997

Simultaneous determination of cysteine sulfinic acid and hypotaurine in rat tissues by column-switching high-performance liquid chromatography with electrochemical detection.

Cysteine sulfinic acid (CSA) and hypotaurine (HT) were determined by electrochemical detection with a glassy carbon electrode at 0.95 V vs. Ag/AgCl. The separation of CSA and HT was accomplished by coupled-column liquid chromatography, consisting of an anion-exchange column and a cation-exchange column. For the determination of CSA and HT in rat tissues, a column-switching system was introduced to remove interferences from late-eluting endogenous substances. The limits of determination were 0.05 microM for both sulfinic acids. The average precisions (C.V.) over the concentration range of 0.05 to 5 microM were 4.3% for CSA and 4.2% for HT.

Animals↗

PubMed1997

Thallium-201 single-photon emission tomography in the treatment follow-up of nasopharyngeal carcinoma.

In order to assess the usefulness of thallium-201 single-photon emission tomography (SPET) in the treatment follow-up of nasopharyngeal carcinoma (NPC), a total of 75 201T1 SPET studies were performed in 18 patients with histologically proven NPC. The findings were compared with those of magnetic resonance imaging (MRI) before and after therapy. Four patients received radiotherapy alone while the other 14 received concurrent chemo-radiotherapy. Treatment response was classified as complete (CR) or partial (PR) based on the findings of MRI and 201T1 SPET. Intense 201T1 uptake by the tumour was seen in all 18 patients before treatment. After treatment, MRI showed seven CRs and 11 PRs, whereas 201T1 SPET showed 13 CRs and five PRs. In 12 patients, the results of 201T1 SPET were in agreement with those of MRI. In six patients MRI showed PR but 201T1 showed CR. Follow-up (mean 10.6 months) MRI and 201T1 SPET studies of these six patients revealed that tumour gradually decreased and finally vanished in three patients. This preliminary study indicates that 201T1 SPET has potential in the assessment of early response to treatment of patients with NPC when compared with MRI.

Carcinoma↗

PubMed1997

Quantitative evaluation in tumor SPECT and the effect of tumor size: fundamental study with phantom.

An experimental study with phantoms was performed in order to evaluate the effect of the tumor volume on the quantitative estimation in tumor SPECT. The ratio of mean count/pixel in the phantom to that of the background (T/N ratio) was well correlated with the size of the phantom: even when the concentration of the Tc-99m O-4 solution of globular phantoms with diameters of 29, 37 and 46 mm was constant, the greater the size of the phantom, the higher was the T/N ratio. This study showed that we should understand that the T/N ratio was certainly affected by the reduction of the tumor size itself whenever we evaluate treatment-response or assess tumor viability after treatment by reference to the T/N ratio.

Evaluation Studies as Topic↗

PubMed1997

Hippocratic thermography.

The thermal measurement method of Hippocrates, which has been referred to as the first for measuring body temperature, was reproduced and the image obtained was compared with an infra-red radiation thermogram. Hippocrates' method involves covering the patient's thorax with an earth-soaked cloth. As the warmer areas dry faster, the pattern of enlargement of the dry area shows the temperature distribution. Therefore, it appears that Hippocrates was the first to obtain thermograms.

Body Temperature↗

PubMed1997

Prevention of peritoneal metastasis of cancer with dextran sulfate--an experimental study in mice.

Peritoneal metastases occur most often in the greater omentum, where tumor implantation sites are densely distributed. We used dextran sulfate (S-Dex) as an anti-cell-adherence agent to prevent i.p. seeded malignant cells from causing peritoneal metastases. S-Dex was tested for its anti-adherent activity against B-16 melanoma cells on plastic, and was examined for its ability to prevent implantation in the omentum and to improve survival in mice after B-16 melanoma was inoculated i.p. S-Dex prevented B-16 melanoma cells from adhering to the plastic wall. S-Dex reduced the number of B-16 melanoma cells implanted into the greater omentum and improved the survival of mice inoculated with B-16 melanoma cells. We conclude that S-Dex attenuated peritoneal metastases when B-16 melanoma cells were seeded i.p.

Animals↗

PubMed1997

[Endoscopic local injection of anticancer drugs bound to carbon particles for treatment of upper digestive tract cancers--clinical trials].

A new dosage formulation consisting of anticancer drugs bound to carbon particles was developed for treating cancers of the upper digestive tract, and is designed to distribute higher levels of anticancer drug to the regional lymph nodes and at the injection site, as compared to a drug in aqueous solution form. Thirteen patients with histologically proven carcinoma (8 with superficial esophageal cancer and 5 with early or proper muscle layer-infiltrating gastric cancer), in whom surgical treatment was contraindicated, received intra- and peritumoral injection of the new dosage formulation (total dose of 35-100 mg of peplomycin or 250-500 mg of methotrexate) guided by esophago- or gastro-fiberscope. Eleven of these 13 patients are currently alive, 12-64 months after therapy, or they died without evidence of recurrence 12-98 months after the treatment. One patient has remained cancer-free for 37 months after a second course of the therapy given to treat a recurrence found 26 months after the first treatment. Another patient has a recurrent tumor 9 months after the therapy and is now going to undergo a second course of treatment. Side effects were not severe and well-tolerable.

Adenocarcinoma↗

PubMed1997

[Visualising lymph nodes by aclarubicin bound to activated carbon particles in breast cancer surgery].

A new dosage formulation (ACR-CH), composed of aclarubicin (ACR) bound to fine activated carbon particles, has been developed for the treatment of lymph node metastases in breast cancer. ACR-CH is designed to (a) adsorb a great amount of aclarubicin and desorb in a free state; (b) distribute a greater amount of ACR for a longer period of time selectively to the regional lymph nodes; (c) be decreased in the systemic toxicity; and (d) enhance its therapeutic effect on lymph node metastases. In this clinical trial in 20 patients with breast cancer, ACR-CH was injected intra- and peritumorally just before operation for breast cancer, and we examined the extent of blackened nodes produced by ACR-CH. ACR-CH blackened about 70% of the axillary lymph nodes with cancer metastasis as well as the nodes without metastasis. In conclusion, ACR-CH will be useful for dissection of lymph nodes by visualizing the nodes during operation for breast cancer.

Aclarubicin↗

PubMed1997

[Quantitative measurement of cerebral blood flow by the microsphere model with super-early 123I-IMP brain SPECT].

Cerebral blood flow (CBF) was quantitatively measured in 6 healthy young volunteers based on "super-early" acquisition of N-isopropyl-p-[123I]iodoamphetamine (IMP) brain SPECT obtained 4-6 min after IMP injection with a three-head rotating gamma camera and the microsphere (MS) model. The ratio of radioactivity (count/pixel/min) in the conventional early SPECT image (taken 25-55 min after IMP injection) to that in the "super-early" image for each brain region negatively correlated with regional CBF value obtained with the "super-early" MS method. This indicates that wash-out of IMP from the regions with higher CBF is faster than that from the regions with lower CBF and that CBF values are underestimated with the conventional MS method in regions with higher CBF. Regional CBF was quantitatively measured with the "super-early" MS method and the ARG method, a recently developed method based on two-compartment model. The mean cortical CBF was 52.5 +/- 7.0 (ml/100 g/min, mean +/- SD) with the "super-early" MS method and 47.5 +/- 3.3 with the ARG method. The CBF values obtained with the "super-early" MS method agreed with those previously reported with positron emission tomography. Since the MS method is theoretically the simplest model, the "super-early" MS method can be applied various disorders of the central nervous system where the behavior of IMP is not fully understood.

Adult↗

PubMed1997

Classification of acceleration waveforms during walking by wavelet transform.

In this study we have attempted to classify the acceleration signal, while walking both at horizontal level, and upstairs and downstairs, using wavelet analysis. The acceleration signal close to the body's center of gravity was measured while the subjects walked in a corridor and up and down a stairway. The data for four steps were analyzed and the Daubecies 3 wavelet transform was applied to the sequential data. The variables to be discriminated were the waveforms related to levels -4 and -5. The sum of the square values at each step was compared at levels -4 and -5. Downstairs walking could be discriminated from other types of walking, showing the largest value for level -5. Walking at horizontal level was compared with upstairs walking for level -4. It was possible to discriminate the continuous dynamic responses to walking by the wavelet transform.

Acceleration↗