生体医工学
Online ISSN : 1881-4379
Print ISSN : 1347-443X
ISSN-L : 1347-443X
48 巻, 1 号
選択された号の論文の19件中1~19を表示しています
研究
  • 西山 潤平, 木下 伸一, 平田 豊
    2010 年 48 巻 1 号 p. 1-10
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    A reliable predictor of drowsiness using objective measures is desirable for machine and vehicle operations in which human errors may cause fatal accidents. Presently, we have evaluated the Vestibulo-Ocular Reflex (VOR) as a possible predictor of drowsiness. The VOR is a compensatory eye movement that stabilizes retinal image during head motion, and is inevitably induced by vibration in a car running on the road. We employed an uneventful driving simulation (DS) featuring vibration stimulation to induce both drowsiness and VOR in healthy human subjects. VOR performance was characterized by gain and residual standard deviation in relation to the subjects' drowsiness. A significant decrease in VOR gain and increase in residual standard deviation accompanied subjective sleepiness, with changes in VOR performance occurring before subjects became aware of sleepiness. From this finding, we developed a reliable method (88.9%accuracy) to predict oncoming sleepiness using changes in VOR performance as a cue.
  • 水野 (松本) 由子, 田中 康仁, 林 拓世, 岡本 永佳, 西村 治彦, 稲田 紘
    2010 年 48 巻 1 号 p. 11-24
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    The aim of this research was to assess the physiological signals which were relevant working efficiency under mental workload. Eleven healthy subjects were examined. In the first step, their mood status and stress level were evaluated with questionnaire methods:“Profile of Mood States (POMS)” and “Stress Self Rating Scale (SSRS)”, respectively. In the second step, electroencephalography (EEG) and photoplethysmography under the mental workload tasks in four auditory stimuli (silent circumstance, white noise, classical music, and up-tempo music) were measured. The mental workload tasks consisted of two parts:performing Uchida-Kraepelin test (calculating task:CAL) on PC monitor in two minutes and fixating on a crosshair image (after CAL) in two minutes. A procedure of the mental workload task in each auditory stimulus was repeated three times. EEG data were analyzed using a discrete Fourier transform to obtain power spectral density (PSD) in theta, alpha, and beta bands. Pulse waves from photoplethysmography were analyzed for estimating the pulse wave amplitude (PWA) and length (PWL). PSDs of theta band in silent circumstance and classical music under and after CALs, alpha band in classical music under and after CALs, and beta band in up-tempo music under CAL on most or all areas were significantly larger than those in the other auditory stimuli. The results of photoplethysmography analysis showed that changes of PWA and PWL in silent circumstance and classical music were more stable than those in the other auditory stimuli. It was suggested that the classical music would not only affect brain activity under the mental workload and augment the efficiency of it, but also facilitate recovery of the physiological conditions from the stressful situations. These events from the physiological point of view showed that working environments could be considered to avoid adding stress on the brain function and autonomic nervous system during and even after the tasks.
  • 吉田 健志, 黒田 嘉宏, 鍵山 善之, 井村 誠孝, 木下 秀文, 松田 公志, 大城 理
    2010 年 48 巻 1 号 p. 25-32
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    In laparoscopic surgery it is difficult to ascertain the force direction from endoscopic images of two organs being dissected by a surgical instrument. Therefore quantitative skill analysis using force sensor with a high degree of freedom would be useful, especially in dissection procedures. We developed a system to measure the force on the tip of laparoscopic instruments with a spatula-shaped-tip. A forceps was cut at 61mm from the tip, and a 3 DOF sensor that can detect vertical and shear forces was installed between the cutting edges. Two experienced laparoscopic surgeons and three novices carried out a dissection procedure using their dominant hand in an in vitro testing using a kidney of the dead pig. For the vertical and shear forces, the timing and intervals of the peak force, the percentage of the forces and the force applying time are examined. Experts applied the vertical peak force earlier than novices when carrying out a dissection procedure, and then gradually relaxed the force. These results suggest that experts try to keep the instrument tip visualized in the operative field.
  • 吉永 崇, 宮崎 航, 田口 侑人, 酒井 太郎, 桝田 晃司
    2010 年 48 巻 1 号 p. 33-41
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Portable echography devices are developed widely. In spite of advantage of being used in disaster stricken area or patient house, portable echography devices have less capability in function compared with that of ordinary size echography. Therefore, we developed 3D shape reconstruction system from some number of contour lines of left ventricle obtained by image processing technique. Radial Basis Function is used to interpolate the shape between contour lines and Marching Cubes algorism is used to extract the surface of left ventricle and approximate it as a triangular set. In this paper, the three-dimensional shape of the left ventricle in systolic phase and diastolic phase are reconstructed by synchronizing electrocardiogram wave pattern with an automatic extraction program of the left ventricle of the heart which we have developed. As a result of ejection fraction calculation by using each shape, this system can output value that was effective for diagnosis. Furthermore, it is considered that we can utilize a portable diagnosis device effectively by applying this system to the follow-ups of the size of the tumor.
  • 中込 哲, 牛山 明, 高橋 美雪, 小笠原 裕樹, 石井 一行, 淺野 牧茂, 大久保 千代次
    2010 年 48 巻 1 号 p. 42-49
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    PURPOSE: It is commonly accepted that sunburn is usually occurred within a couple of hours after Ultraviolet B (UVB) irradiation. However, we recently demonstrated that increased microvascular permeability and vasodilatation of venules were observed within a few minutes after UVB irradiation to the skin in mice. To elucidate mechanisms to be involved, we used various pharmacological inhibitors concurrently with UVB irradiation. METHODS: Dorsal Skinfold Chamber (DSC) and fluorescence intravital-microscopy techniques were applied to Hos: HR-1 hairless mice for measuring the microcirculatory parameters including vascular permeability, vascular diameter, and leukocyte behavior by using fluorescent dye. L-NAME (NOS inhibitor) . Edaravone (free radical scavenger) . Indomethacin (non-selective COX inhibitor) . and Celecoxib (COX-2 selective inhibitor) were administrated to the mice prior to UVB irradiation and evaluated the efficacy of each inhibitor on microvascular events mentioned above. RESULTS&CONCLUSION: A significant increase in vascular permeability, venular diameter and rolling and/sticking leukocyte counts was observed within a few minutes after UVB irradiation at 240mJ/cm2. The increased vascular permeability was significantly reduced by administration of all the inhibitors. In contrast, increase in venular diameter and rolling/sticking leukocyte counts was not affected. These results indicate that the increase of vascular permeability within a few minutes after UVB irradiation is related to ROS, NOS and COX activation. The reaction of vascular permeability is a common signal pathway at the inflammation process including sunburn. These results suggest that the common signal pathway under inflammation process may be also involved immediately after UVB irradiation.
  • 谷田 惣亮, 菊池 武士, 大月 喜久子, 安田 孝志, 古荘 純次, 小澤 拓也, 藤川 孝満, 森本 正治
    2010 年 48 巻 1 号 p. 50-58
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Ankle Foot Orthosis (AFO) are orthotic devices to support movements of ankles of disabled people, for example hemiplegia, cerebral palsy, neuromuscular disease, etc. In our research, we have developed a passive controllable AFO (Intelligently Controllable Ankle Foot Orthosis: i-AFO) which can control its ankle torque by using a Compact Magneto-Rheological Fluid Brake (CMRFB), for improvement of the walking function of the handicapped person. The brake has a simple structure and rapid response. Until now, we have developed the CMRFB and 2nd prototype i-AFO, and evaluated their function. Consequently, the gait had been improve, so the joint movement was smooth which close to normal gait. In this paper, we describe newly developed i-AFO, 3rd prototype. This device was small and lightened to use more compact CMRFB and spring unit, and we used accelerometer and potentiometer for judgment of walking states. Additionally, velocity controller works in initial stance phase to maintain stable gaits even if the walking speed changes. We conducted validation test of new device and controller for a Guillain barre syndrome patient. According to experimental results, velocity of ankle planter flexion in the initial contact phase was an important factor for good gaits, and we could control it with the 3rd i-AFO.
  • 宇野 富徳, 王 力群, 三分一 史和, 外池 光雄, 金田 輝男
    2010 年 48 巻 1 号 p. 59-65
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    We investigated the olfactory “Kansei” information processing for two kinds of smells by measuring the brain activities associated with olfactory responses in humans. In this study, the brain activities related to discrimination and recognition of odors were examined using functional magnetic resonance imaging (fMRI). In experiment 1, odor stimuli (lemon-like and banana-like) were presented using a block design in a blinded manner, and the kind of fruits was identified by its odor. The frontal and temporal lobe, inferior parietal lobule, cingulate gyrus, amygdaloid body and parahippocampal gyrus were primarily activated by each odor based on conjunction analysis. In experiment 2, as a result of performing an oddball experiment using the odors of experiment 1, the active areas were mainly found in the temporal lobe, superior and inferior parietal lobule, insula, thalamus, supramarginal gyrus, uncus and parahippocampal gyrus. Moreover, these regions overlapped with the emotional circuit. These experimental results suggest that common brain activities accompany the discrimination and cognition associated with odor stimuli, which may underlie the olfactory responses relevant to the higher brain function and emotions associated with olfactory function.
  • 松原 佳亮, 渡部 浩司, 林 拓也, 湊 小太郎, 飯田 秀博
    2010 年 48 巻 1 号 p. 66-74
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Patlak analysis, which estimates the net FDOPA influx constant (Ki) by linear regression of data acquired from [18F] FDOPA PET study, is widely employed in the diagnosis of neurological disorder, such as Parkinson's disease. In Ki estimation by Patlak analysis, it is assumed that the metabolites of radioligand do not diffuse out of the tissue during PET scan. However, [18F] F-Dopamine, synthesized from [18F] FDOPA, is rapidly metabolized and its metabolites diffuse from the tissue. We aimed at the evaluation of the effect of dopamine metabolism and the clearance of its metabolites on Ki estimated by Patlak analysis. For this purpose, we developed a model describing the detailed pathway of dopamine kinetics in the striatum, and a standard time-activity curve (TAC) was generated based on this model and [18F] FDOPA PET data of a monkey. And TACs in case of altering the dopamine metabolism or the clearance of its metabolites were simulated. Then, we evaluated Ki values estimated by Patlak analysis for these simulated TACs. Ki was increased when the dopamine metabolism to DOPAC (k9dopac) and the clearance of DOPAC and HVA (k11dopac, k11hva) were altered. The results suggest that Ki could be biased by the influence of the metabolism of dopamine and clearance of its metabolites. Therefore, it is important to consider these biases in the interpretation of Ki value estimated Patlak analysis.
  • 井村 誠孝, 黒田 知宏, 鍵山 善之, 黒田 嘉宏, 大城 理, 東 寛子, 八木 雅和, 高田 健治
    2010 年 48 巻 1 号 p. 75-82
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Three-dimensional volume data set is useful for diagnosis in dental treatments. However, to obtain three-dimensional images of a dental arch in general dental clinics is difficult. In this paper, we propose a method to reconstruct pseudo three-dimensional dental images from a dental panoramic radiograph and a tooth surface shape which can be obtained from three dimensional shape measurement of a dental impression. The proposed method finds an appropriate curved surface on which the dental panoramic radiograph is mapped by comparing a virtual panoramic image made from a tooth surface shape to a real panoramic radiograph. The developed pseudo three-dimensional dental images give clear impression of patient's dental condition.
  • 西垣 孝行, 小川 浩司, 四井田 英樹, 高橋 裕三, 吉田 幸太郎, 西岡 宏, 林 輝行, 人見 泰正, 水野 (松本) 由子
    2010 年 48 巻 1 号 p. 83-92
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Heart transplantation in children is not permitted and ventricular assist device of children has not developed in Japan. An operation or an adjunct treatment by extracorporeal membrane oxygenation (ECMO) is an exclusive treatment of the children with severe cardiac failure. However, the ECMO system for children is behind developing in comparison with one for adults. In particular, the ECMO system can cause the problems which deteriorate the patients' conditions. Major problems of the ECMO system are as follows: priming volume and blood-contacting surface area in the ECMO system are large for children. Therefore, it is necessary that ECMO device will be developed to improve the treatment outcome. Our future goal is to downsize the ECMO device. In this fundamental research, we focused on evaluating the temperature characteristics of the ECMO system. Our experimental devices consisted of two parts: a simulated patient's side and the ECMO system's side. We measured temperature differences between inlet and outlet of the ECMO system under the seven experimental conditions. We compared temperature differences between ECMO control conditions: fluid flow rate, V/Q (oxygen flow rates/fluid flow rates), temperature around ECMO system and temperature of inlet oxygen gas. The results showed that the temperature differences were significantly influenced by V/Q and temperature around ECMO system. There were no significant differences with temperature of inlet oxygen gas. In conclusion, we found that the ECMO system can have the thermal heating effect when the temperature around ECMO system was at 43 degrees Celsius, and oxygen flow rate was 5.0L/min. These results suggested that we would develop the small applicable heating system instead of the conventional large heat exchanger, and it would realize that the ECMO system could be downsized.
  • 金倉 智行, 稲本 辰巳, 萩原 啓
    2010 年 48 巻 1 号 p. 93-97
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    The alpha attenuation test (AAT) has been developed within the last few years as a method to measure vigilance levels using electroencephalogram (EEG) . However, measuring vigilance levels by the AAT is complicated and time-consuming, as electrodes need to be attached to the subject. The present study examined the influence of changes in the number of alpha waves on vigilance level and attempted to find a relationship between postural sway and vigilance level. If a mutual correlation could be found between vigilance level and postural sway, measurement of vigilance level could be simplified. The results showed that postural sway increases as vigilance level decreases. In particular, head sway and alpha waves displayed a significant correlation. We thus expect that vigilance levels will be able to be measured using head sway as a substitute for EEG in the future.
  • 蘇日塔拉図, 外山 寛, 小杉 剛, 木竜 徹, 林 豊彦, 飯島 淳彦, 前田 義信, 山崎 健
    2010 年 48 巻 1 号 p. 98-105
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Visually induced motion sickness is one of the detrimental effects of video images on human psychosomatic state. Several studies for alleviating this effect have been cumulated in recent years. One of the studies reported that people with high heart rate tended to be immune to the motion sickness. This fact motivated us to assume that the increase of subjects' heart rate through physical exercise before video watching could prevent them from the motion sickness. Then we investigated the effects of video exposure with such pre-exercise on the motion sickness. First we recorded psychosomatic state of 23 volunteers using the simulator sickness questionnaire (SSQ) before and after watching extremely unpleasant video images of a mountain-bike ride capable of visually inducing motion sickness. Then we classified them into nausea and non-nausea groups, based on SSQ evaluation. Subjects' heart rate in nausea group increased gradually during video exposure, while that in non-nausea group was nearly constant. By imposing a 5-minute pre-exercise on 12 subjects in nausea group before video exposure, 10 subjects became immune to the motion sickness, demonstrating that the pre-exercise would be efficient for alleviating the motion sickness. In addition subjects' heart rate in nausea group remained at a higher level during video exposure than at rest, whereas it returned to the rest level immediately after the pre-excise without video exposure.
  • 村上 慎吾, 鈴木 慎悟, 上島 豊, 野村 泰伸, 倉智 嘉久
    2010 年 48 巻 1 号 p. 106-114
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    A number of drugs in clinical use and during development have had to be withdrawn because of their proarrhythmic side effects. These otherwise promising compounds are a risk for patients and force the pharmaceutical industry to bear enormous costs. For assessment of potential risk of drug-induced cardiac arrhythmia, the effects of a drug on the Human ether-a-go-go related gene (HERG) channel expressed in either mammalian cells or Xenopus oocytes, and the prolongation of action potential duration (APD) and QT interval in animals, are now routinely measured. However, there are enough examples to indicate that these tests are not accurate or sufficient to assess the proarrhythmic risk of drugs. Therefore, further development of prediction methods for risk assessment is awaited to increase safety in drug usage in clinics and in new drug development. An in silico strategy has particular merits for this purpose, because, different from purely experimental approaches, it can easily deal with the diverse actions of the drugs. The in silico assessment of a drug's proarrhythmic risk requires a method that provides quantitative and comprehensive comparison of the effects of different forms of IKr-blockade upon APDs and transmural dispersion of repolarization (TDR). Previously, we have developed various cardiac action potential models, as well as a novel risk-assessment method based on IKr-IKs, two-dimensional maps of APD and TDR. In the present paper, we introduce a new prediction system based on cardiac action potential simulation and model database. This system consists of registered models, accumulated calculation results, computer cluster and client software. Various procedures for simulation and analysis can be executed on the web. The developed prediction system may be a useful tool to predict the risk of drug-induced arrhythmia.
  • 榎本 崇宏, Udantha R. ABEYRATNE, 楠本 哲也, 芥川 正武, 近藤 英司, 川田 育二, 東 貴弘, 小中 信典, ...
    2010 年 48 巻 1 号 p. 115-121
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    Snoring is the earliest and the most common symptom of Obstructive Sleep Apnea (OSA) . Quantitative analysis of snoring, however, is not used at present in the clinical diagnosis of the disease. Several researchers have reported differences in the formant frequencies of Apneic and benign snoring sounds (SS) based on linear prediction coding (LPC) analysis. However, SS is complex signal and at local low signal to noise ratio (SNR) . This signal complexity should reduce the accuracy of formant estimation. In this paper, we propose a novel approach to the diagnosis of OSA based on the formants of SSs, extracted via a noise-robust linear prediction technique. The proposed method and existing LPC-based method are compared via a measure, σ which indicates the standard deviation of first formant frequencies. The performance of the proposed method was evaluated on a database of clinical snoring sounds recorded overnight in the laboratory of a hospital sleep diagnostic center. Compared with existing LPC-based method, we show that the proposed method can differentiate (sensitivity: 88.9%, specificity: 88.9%, AUC: 0.85) between benign snoring (Apnea Hypopnea Index, AHI=6.0±3.2 event/h; 6188 episodes) and apneic snoring (AHI=40.7±20.2 event/h; 14066 episodes) .
  • 大無田 孝夫, 柴田 仁太郎
    2010 年 48 巻 1 号 p. 122-127
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    <Background and purpose> Atrial fibrillation (Af) associated with basic heart disease is known to be complicated with severe ventricular tachyarrhythmias. QT interval is one of the predictors of the cardiac arrhythmia development. However, it is not easy to determine the end of the T wave because of the baseline shift by fibrillation waveforms. We previously developed a new QT interval measurement system using wavelet transform, which enables automatic QT measurement which shows mean error of less than 5ms. The purpose of this study is to assess beat to beat QT interval as well as RR interval in Af. <Cases and method> Five minutes continuous ECG recording (lead II) was performed in 11 Af cases and 6 healthy sinus rhythm cases (SR) . QT intervals were identified by originally developed automated measurement system, in which wavelet transform method (mother wavelet: Mexican hat) was applied to determine the terminal portion of T wave, even if the baseline was fluctuated by the fibrillation waveform. <Results and conclusion> In Af cases, the fluctuation of QT interval by the fluctuation of RR interval was different from SR. However, both SR and Af may actually show a same logarithm-shaped response, and a difference of the variation area for the heart rate interval may contribute in the difference of the distribution. New QT interval measurement method using wavelet transform method is useful in Af cases even if fibrillation waveform interfere the end of T wave.
研究速報
  • 福田 浩, 岡部 勇一, 新藤 一彦, 嶋田 純一, 芳賀 恒之
    2010 年 48 巻 1 号 p. 128-132
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    We have developed a ubiquitous healthcare system by applying active tag technologies. The system can monitor steps walked, weight and blood pressure. The system's operation involves three processes. First, an active tag electromagnetically coupled with sensors collects the user's data. The data is then transmitted into the air when the user just walks around a gate, which sends a trigger signal to the active tag to transmit the memorized data, and a reader (an antenna) receives the data. Finally, the data is written into a database via a network. Our system can operate in open-air areas because the active tag enables long-distance communication. Since our system does not require any kind of PC operation, the workload on users is reduced. We experimentally confirmed that, in our system, the data transmission must be repeated more than five and the gate-reader distance must be shorter than 20m for reliable data transmission. Results of a six-month trial conducted in our laboratories confirmed that our system can obtain vital data for healthcare counseling.
  • 加藤 智久, 佐藤 稔, 山本 紳一郎, 米田 隆志, 中澤 公孝
    2010 年 48 巻 1 号 p. 133-138
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    A lot of previous studies have developed various exercise methods and devices in order to provide exercise effective for maintaining good health. In particular, it is recently well-known that underwater gait-training is a useful fitness movement especially for elderly person. The purpose of this study was to develop a device to induce locomotor-like stepping movements by injecting jet-water to foot sole of a person sitting in a bath. We then investigated the behavior of the leg joints caused by the fluid force in healthy subject. The result shows that the new device can induce reproducible locomotor-like stepping movement by effectively flexing hip, knee and ankle joints.
  • 水庫 功, 関根 正樹, 田村 俊世, 木村 穣
    2010 年 48 巻 1 号 p. 139-144
    発行日: 2010/02/10
    公開日: 2010/11/17
    ジャーナル フリー
    According to one-year blood pressure monitoring, we investigate the index of the self-control, and effective and safety intervention by physician. The one-year morning systolic pressures in two subjects were analyzed with exercise, sleep and body weight. The multiple regression analysis was carried out the blood pressure and other physiological parameters. As the results, the self-control items such as exercise and sleep were differed from the individuals. Furthermore, our results show that 1) we need a long-term exercise with at least 300 kcal per day to decline the blood pressure 2) the walking is easy exercise, but the variation was large because of the different daily condition for the elderly, and 3) therefore we strongly recommend a simple exercise in the home.
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