In order to validate Total Body Score (TBS) as an index for comprehensive evaluation of human body, we examined relationships between TBS and parameters which are correlated with metabolic syndrome (MS). Receiver operating characteristic (ROC) curve analysis showed that TBS is a useful index for MS screening. TBS had statistically significant correlations with systolic blood pressure, diastolic blood pressure, neutral fat, HDL cholesterol, visceral fat, and subcutaneous fat. The subjects who had low TBS showed statistically high probability to have one or more MS risk factors. The result suggested that assessment with cross-sectional biomedical data is useful for screening of MS risks.

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In this study, we fabricated micro planar coils as a receiver for a high sensitive MRI (Magnetic Resonance Imaging). According to the calculation of the scale effect, the sensitivity of the coil increases with decrease of the diameter of the coil under the condition of fixed inductance. The micro planar coils of 5 and 20 mm in diameter were fabricated by using MEMS technology. The resistance and inductance of the 20 mm coil were 1.4 Ω and 1.15 μH at 8.5 MHz, respectively. Those of the 5 mm coil were 2.0 Ω and 1.05 μH, respectively. The MRI signal receivers were made by attaching the micro coils to the tip of acrylic pipes. The SNRs (Signal to Noise Ratio) of MR images of phantom were measured by the micro planar coils and the medical MRI coil of 200 mm in diameter. The SNRs of MR images taken by the micro planar coils were about 8 times as high as the MR image taken by the medical coil. MR images of an okra (Abelmoschus esculentus) were acquired by fabricated MRI signal receivers with the voxel size of 2.0 × 2.0 × 2.0 mm³ and 0.5 × 0.5 × 1.0 mm³. Since the sensitivity of micro planar coils was high, we were able to clearly observe inner structure of the okra.

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Concerning the rehabilitation protocols for arm movements in stroke patients, many studies had conducted by executing a point-to-point movement. In general, the point-to-point reaching movement was forward/backward or right/left direction exercise, whereas the circle-drawing task needed to achieve these two directions simultaneously. From the viewpoint of the motor planning, the circle-drawing movement would be useful as upper limb rehabilitation protocol. However, there is no evidence of restored antiphasic electromyographic (EMG) activities in biarticular arm muscles using circle-drawing tasks in a planar plane. The purpose of this study was to investigate whether or not the restored antiphasic EMG activities in biarticular arm muscles reflected improved smooth motor performances in stroke patients after 10 days of two-joint arm-movement training. Three male sub-acute stroke patients, whose left arms were paralysis, performed point-to-point movement and circle-drawing tasks using haptic device system (Mitsubishi Precision Co., Ltd.) for upper limb neuromuscular rehabilitation. After the training, the movement velocity and achievement periods increased with the enhancement of the antiphasic EMG activities in biarticular arm muscles, whereas there was a decrease in the jerk after training for the same duration. These results suggested that stroke patients could achieve smooth motor performance with restoringthe antiphasic EMG activities in biarticular arm muscles by practicinga two-joint arm movement, especially, circle-drawing.

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A two-dimensional blood flow simulation was carried out using a particle method to investigate effects of motions of red blood cells (RBCs) on blood flow properties in a micro bifurcated blood vessel. Blood plasma and RBCs were considered as blood components, and the RBC were modeled as a viscous fluid encapsulated by an elastic cell membrane. The elastic properties of the membrane were expressed by a spring model. The incompressible and viscous flow was assumed for the blood plasma and the inner fluid of the RBC, and the coupled analysis of the flow and the membrane deformation was accomplished by the MPS method. A symmetric micro bifurcated vessel model was constructed in which the vessel widths were 11.2 μm for the parent vessel and 9.0 μm for the daughter vessels, and inflow hematocrit was set 0.30.As a result of blood flow simulation, RBCs in straight vessel parts were deformed into parachute-like or slipper-like shapes. Unsteady aggregation of RBCs was exhibited at the bifurcation. The apparent viscosity at the bifurcation was changed in time according to the change in the hematocrit value, and this behavior influenced the change in the apparent viscosity of the entire bifurcated vessel. The relative apparent viscosity with respect to the plasma viscosity was changed from 0.8 to 5.9 at the bifurcation, and the time averaged viscosity at the bifurcation was approximately 3.5 times greater than that in straight parts.

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As induction heating (IH) equipments are getting widely used, the intermediate-frequency magnetic fields emitted by these equipments have been attracting much attention especially from health and safety viewpoints. However, studies on microcirculation are scarce. Here, we aimed at evaluating possible effects of the magnetic field (24 kHz) emitted by an IH on isolated perfused small arteries. Mesenteric arteries (346 ± 30 μm) of Wistar rats (n = 12 for both exposure and control groups) were isolated and perfused with a vessel perfusion system (0.02 mL/min, 90 mmHg). A table-top type IH was located 250 mm apart from a vessel. Each vessel was then exposed to a magnetic field of 7.8 μT for 10 min. Inner and outer diameters were measured during and after exposure. Insignificant decreasing trends (< 1%) of vessel diameters were noticed; however, no statistically significant changes were observed compared with the control group.

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Recently it was suggested that moderate hypothermia would improve cardiac defibrillation success ratio and decrease voltage to defibrillate. Moderate hypothermia (MH, 33°C) represented better results against Normal condition (37°C). but sever hypothermia (30°C) had worse performance than MH. It was still unclear why and how MH improves cardiac defibrillation and the reason that MH was the best thermal parameter. We optically mapped point shock-induced virtual electrode polarization (VEP) and new excitation propagation starting from VEP in three temperature condition (37, 33, 30°C) and analyzed the shock after excitation manner (Not capture, Break excitation and Make excitation) using two indices (% Repolarization and Phase APD). In two indices both, the band of break excitation was significantly decreased in MH condition. The results suggested that the repression of break excitation in MH condition prevents shock after reentrant excitation wave and this mechanism brings to improvement of defibrillation success.

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We pursue research and development on the detection of the weak magnetic field generated by the neural propagation along the spinal cord and the investigation of non-invasive diagnosis of spinal cord function based on the analysis of the detected magnetic signals. So far, we have reported the developed prototype of the SQUID spinal cord evoked magnetic field (SCEF) measurement system applicable to patients with spinal cord disorder in actual hospitals. We have also reported the development of the visualization of the current distribution along the spinal cord by magnetic source analysis. In this paper, the improvement of the dynamic range by the newly designed multiple feedback FLL (flux locked loop) and the noise reduction using reference magnetic flux sensors are described. These features enabled to prevent saturation of the SQUID electronics and to detect separately not only the fast SCEF component reported previously but also the slow SCEF component simultaneously even in the presence of large low-frequency noise.

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We demonstrated an on-chip CO₂ incubation system suitable for microfluidic cell culture that does not need an external chamber or gas supply. A nested pair of reservoirs for liquids insulated by gas/vapor-permeable poly (dimethylsiloxane) (PDMS) enabled CO₂ incubation of media stored in the inner reservoir. This was achieved by only flowing heated sodium bicarbonate solution through the outer reservoir. The stabilization capability of temperature and pH was evaluated in situ with a miniature thermocouple and by absorption spectroscopy of phenol red, respectively. The temperature and pH were stabilized within the range of 37.0 ± 0.2°C and pH7.3 ± 0.2 over at least 24 hours. This incubation capability was demonstrated through low-density microfluidic culture of CV-1 epithelial cells under an inverted microscope for three days.

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In a previous study, we investigated electromagnetic heating with various types of metals for the purpose of mild ablation in cancer treatment. The aim of this study is to determine the efficacy of induction heating in the treatment of cervical cancer by using xenograft animal models of human cervical cancer. Nude mice with CaSki cells mimicking human cervical cancer were treated by induction heating. To investigate the influence of this method on tumor growth, 9 nude mice were assigned to 3 experimental groups: heating group, non-heating group, and control group. In the heating group, tumor-bearing mice were placed for 10 min under an alternating magnetic field (AMF) after needle insertion, while in the non-heating group, a needle was inserted into each animal, but AMF treatment was administered. The tumor growth could be controlled using this method without any risk of skin burn injury. The mean tumor volume was lesser in the heating group than in the control group. Thus, this new ablation method may be a feasible technique for cervical cancer therapy.

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The purpose of this study is to evaluate the viscoelastic characteristics of the anterior tibial muscle based on system identification of evoked mechanomyogram (MMG). Input data consisted of the electrical stimulation of common peroneal nerve, which made the anterior tibial muscle contract. The output data consisted of the evoked MMG. The MMG was detected with an accelerometer attached to the anterior tibial muscle. Seven healthy male subjects participated in the experiment. The electric pulses whose width were 500 μs were applied to common peroneal nerve five times with inter-pulse intervals of 300 ms, and the data were acquired for 1.5 s at sampling frequency of 2 kHz. The measurements were carried out at six contraction levels. The evoked MMG was well estimated with the tenth order transfer function. Then the transfer function was decomposed to five sets of the second order transfer function. The coefficients of the second order function provide the viscoelastic characteristics.There were significant correlation between contraction level and the elastic indices in many cases. On the other hand, the viscous indices often did not show significant correlation. The elastic indices were classified into two groups. One increased as the contraction level increased, but another remained unchanged. We supposed that the former indices corresponded to the muscle elasticity and the latter ones corresponded to the passive elasticity such as subcutaneous fat or skin.

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The authors developed an axillary crutch walking trainer for an untrained patient. Up to now, it was confirmed that an untrained patient could acquire a skill of regular axillary crutch walking with the developed trainer. The trainer warns immediately the patient against the inadequate usage, that is, the axillary crutch was leaned more than the threshold angle while walking. In this paper, a method of calculating an acceleration of the body of a patient was proposed, so that a patient could be warned in case the possibility of falling is estimated. Because while a leg is in swing phase, the acceleration of the body of a patient affects the balance of the body after landing, it is important to calculate the acceleration. Although the acceleration of the body can be measured by an acceleration sensor attached to the body, the attachment may disturb a smooth walking. Therefore, a method of estimating the acceleration of the patient's body from an axillary crutch walking trainer's motion without an acceleration sensor was proposed. Through experiments, usefulness of the proposed method was confirmed. Additionally, possibility of estimate of ZMP was confirmed.

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The degeneration of articular cartilage impairs primary functions such as the load transfer and/or distribution, and the dysfunctions of cartilage harms active daily life seriously. Evaluation of the cartilage degeneration, particularly the resultant alteration of material/mechanical properties, is crucial for effective treatments. In this study, the mechanical properties of normal and enzymatically degenerated cartilage of the bovine femoral heads were examined by standard indentation test, and the difference of degeneration effects between the medical region (a load-supporting region) and the lateral region (a non load-supporting region) was evaluated. Furthermore, the material composition and the microscopic structure were observed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. The elastic modulus was decreased by collagenase-treatment at both regions and no difference was found in the collagen and proteoglycan contents between lateral and medial regions. The orientation of collagen fibres in the degenerated tissue did not differ significantly from that in normal cartilage at both regions.

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If we regard skeletal muscle as an actuator, we see it has excellent flexibility and efficiency, properties that artificial actuators such as electric motors or mechanical engines do not have. We have been researching the creation of miniaturized bio-actuators that use cultured skeletal muscle. We reported that stimulation was very important to culture myoblast and to develop skeletal muscle. We obtained skeletal muscle by cultivating C2C12 cells using unidirectional mechanical stimulation. We developed a Bio-Actuator System as a mode for a skeletal muscle system in which this cultured skeletal muscle was used as actuator unit. This Bio-Actuator System was made to imitate the musculoskeletal system and consisted of one joint, two arms, one flexor muscle and one extensor muscle. One arm was fixed on the base, and the other arm was able to rotate freely about the joint axis. Because skeletal muscle can only contract, we used cultured skeletal muscle as flexor muscle and sliced silicon elastic sheet as extensor muscle. Experiments were conducted with this Bio-Actuator System in a culture medium. By applying pulsed voltage to the culture medium, the bio-actuator unit was contracted and relaxed. By repeating these contractions and expansions, we observed that the tip of the arm vibrated periodically.

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The mechanism to encode and store the information on time is essential to uncover the nature of temporal information processing in the sensory, memory and higher-order areas in the brain. In this article, the results of psychophysical experiments on short-term memory of tone durations in auditory sequence were reported. Subjects were requested to recall the durations of all the tones presented serially (sequence) by a telegraph key. The performance of recall was evaluated by correlation coefficients and the distribution in correlation diagram between presented and recalled tone durations, and the relationship to the serial order and the number of tones in a presented sequence were investigated. It was shown that the performance of the recall of tone durations could be evaluated by cross-correlation, and the performance decreased when the serial order of the target tone in the presented sequence was later or the number of tones in a sequence was larger. It was also shown that there were some types of characteristic distribution on the correlation diagram between presented and recalled tone durations which corresponded to the degree of memory decay. This result indicated that the behavioral process of memory decay of the analogue (non-categorized) information could be observed by the profile of correlation diagram.

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There are several medical imaging scanners and each modality has different aspect for visualizing inside of human body. By combining these images, diagnostic accuracy could be improved, and therefore, several attempts for multimodal image registration have been implemented. One popular approach is to use hybrid image scanners such as PET/CT and SPECT/CT. However, these hybrid scanners are expensive and not fully available. We developed multimodal image registration system with USB cameras, which is inexpensive and applicable to any combinations of existed conventional imaging scanners. The multiple USB cameras will determine the three dimensional positions of a patient while scanning. Using information of these positions and rigid body transformation, the acquired image is registered to the common coordinate which is shared with another scanner. For each scanner, reference marker is attached on gantry of the scanner. For observing the reference marker's position by the USB cameras, the location of the USB cameras can be arbitrary. In order to validate the system, we scanned a cardiac phantom with different positions by PET and MRI scanners. Using this system, images from PET and MRI were visually aligned, and good correlations between PET and MRI images were obtained after the registration. The results suggest this system can be inexpensively used for multimodal image registrations.

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The combination of MR guided surgery and computer aided surgery has a potential to ensure accurate, certain, and safe procedures. Although a tracking device is indispensable for computer assisted surgery, conventional tracking devices are not available or difficult to use in a MR scanner because of occlusion and strong magnetic field. We proposed a novel tracking method by using MR scanner. The method provides three dimensional positions and orientations of a miniature receiver coil (tracking coil) consisted of three marker coils and tuning capacitor, and matching capacitor. We describe experiments we conducted to evaluate the basic performance of the method. First, a surgical tool affixed the tracking coil was calibrated. Next, measurement accuracy of the tool's tip position and orientation was evaluated. The error of root mean square was 0.92 mm and 0.47 degree. This paper recommends a tracking method for computer assisted surgery with MRI to enable tracking in MR environment. Results obtained with the method demonstrate its feasibility.

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To clarify mechanisms of the bone-conducted ultrasonic (BCU) perception, tympanic membrane (TM) vibrations under BCU stimuli were measured in a human subject using a laser Doppler vibrometer (LDV). We presented a signal processing algorithm to increase the SNRs (signal-to-noise ratios) of measured LDV signals by removing only optical noise components from the wave signals. Further, we analyzed the TM vibrations using the presented method to investigate the contribution of nonlinear distortion in the BCU perception, i. e. the possibility of generating the audible subharmonics. As a result, we did not find any audible signals corresponding to the subjective pitch of BCU in the TM vibrations. This suggests that there is no evidence for nonlinear distortion in the outer and middle ear.

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For angiogenesis and wound healing, endothelial cells (EC) plays an important role in cell migration and covering over inner vessel wall. Cell migration often induces many polarizations like local distributed and activated molecules, and inhomogeneous membrane viscosity. These polarizations would support variations of signal transduction production at different regions in living cells. It is clear that polarization is associated with microtubule network which is a path for directed molecular transportation. Because of this, observing microtubule structure is a useful approach to investigate polarization scheme in living cells. But within the cell, microtubule organization is not in a stable and uniform structure because microtubule reorganization is derived from repeated tubulin-polymerization and depolymerization. So in order to investigate the mechanisms of microtubule reorganization, measuring the partial behavior of microtubules is crucial task for us. For this reason, we visualized local microtubule using photocromic fluorescent protein called Dronpa. As a result, we confirmed that the fluorescent decay intensity at visualized region associated with microtubule stability and analyzed partial microtubule stability by measuring the time constant τ of the fluorescent decay intensity. On migrating endothelial cell, we selected three regions: 1.Fibrous structure, 2.Tip of microtubule (Plus end) and 3.Rear edge of migrating cell, and measured local microtubule stability, respectively. Comparing time constants among three locations of microtubule, we found that microtubule at Plus end (τ_PE= 167 ± 15 [sec] (mean ± S. E.) ) and Rear edge (τ_Rear= 153 ± 16[sec] were unstable than microtubule constructing Fibrous structure (τ_FS= 225 ± 17 [sec] ) . In this study, we established a new method for partial microtubule visualization using photocromic fluorescent protein and using this method we managed to measure local microtubule stability in living cell.

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Endothelial cells are exposed to mechanical stimuli from blood flow and blood pressure. However, it is not yet fully understood how their simultaneous exposure affects endothelial function. Firstly, in this study we investigated the effect of combined stress on morphology of cultured human aortic endothelial cells (HAECs). In the results, HAECs exposed to steady flow (1.5 Pa, 100 mmHg) were more elongated than those exposed to hydrostatic pressure (100 mmHg) and HAECs exposed to pulsatile flow 1 (1.2/1.8 Pa, 80/120 mmHg) were more elongated than those exposed to steady flow. Similarly, HAECs exposed to pulsatile flow 1 were most oriented to the flow direction among these three stresses. Secondly, we investigated the effect of combined stress on gene expression of cell adhesion molecules in HAECs. After stress exposure to HAECs the mRNA of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin were measured by real time RT-PCR. In the results, the exposure of steady flow increased the mRNA levels of ICAM-1 compared to the exposure of hydrostatic pressure, however, the exposure of pulsatile flow 1 decreased the mRNA level of ICAM-1 compared to the exposure of steady flow. Moreover, the exposure of pulsatile flow 2 (1.2/1.8 Pa, 180/220 mmHg) increased mRNA levels of ICAM-1, VCAM-1 and E-selectin compared to the exposure of pulsatile flow 1. These findings suggest that gene expression of cell adhesion molecules induced by combined stress were different to the superposition of individual stress and that not only difference in the components of combined stress but also difference in the magnitude of the components of combined stress are important.

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Fluorescence spectrophotometry enables highly sensitive measurement of a residual material in tissue and blood. In this study, we newly developed a high-sensitive measurement system for a fluorescence labeled substance even in a highly scattering solution, in which fluorescence detection using conventional fluorescence spectrometers would be very difficult. In the new system, the use of a laser for the light source provided a high-density light that effectively excites fluorescent substances. In addition, fast measurement of faint fluorescence was achieved by using a high-sensitive CCD camera combined with a multichannel spectrograph. The use of these instruments in the system led to increases in detection sensitivity by 10 fold in a transparent solution and by 10000 fold in a highly scattering solution, compared to the detection sensitivities of a conventional fluorescence spectrophotometer. Using the new system, we evaluated the in vivo kinetics of a fluorescence-labeled agent (Alexa488-DPc/m) that we have newly synthesized. The new system provided reliable measurements of accumulation of the agent in tumors and circulation time of the agent in blood even 81 h after administration of the agent.

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This paper proposes a new method of the distiniction method of the newborn rat brain damage using heart beat interval information. We investigated the factor related to the brain damage by using the hypoxic-ischemic encephalopathy model of the newborn rat. From the experiment results, significant factors were the coefficient of variation of the heartbeat intervals and the histogram information. The proposed distinction method succeeded in 21 distinctions in 25 newborn rats (brain non-damage 16 and brain damage 9). This paper shows that it becomes possible to judge the brain damage of an actual embryo by using the heartbeat interval information at the early stage.

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In order to studythe application of event-related potential (ERP) for performing evaluation of food, the ERP was measured when subjectively judging the appearance of foods by three-grade scale with the opinion “Like” and “Favorite”. Sushi was selected as typical foods. And six pictures of sushi were chosen in such a way that it did not consist of disliked sushi of the subjects. As a result, the P300 component of the ERP was detected, and the P300 area (surrounded by ERP waveform and x axis from the latency 250 to 500 ms) became larger when the subjects judged as “Favorite”.

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Many kinds of artifacts may interfere in vital signals, especially in the case of neonatal signal measurement because of unpredictable motion. We observed neonatal SpO₂ pulse wave data with high-amplitude artifact by stroking its back after nursing. The frequency of this artifact was around 1.35 Hz. This frequency was within the range of pulse oximeter band-pass filter (0.5∼5 Hz). We could not narrow the range of the filter band because of the possibility of losing the pulse wave frequency. In this study, we tried the time domain processing rotation matrix and separation matrix. We could obtain good pulse waves separated from artifact.

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