Biomedical subjects

Tomoaki Kimura

Publications and source records attributed to Tomoaki Kimura.

11 recordsLinked to original sources

PubMed2006

Factors that influence the applicability of sham needle in acupuncture trials: two randomized, single-blind, crossover trials with acupuncture-experienced subjects.

OBJECTIVES: In recent years the retractable type of sham needle has been anticipated to be a possible solution for masking patients in acupuncture research. However, this needle has been intended mainly for acupuncture-naïve subjects. The authors' goal in this study was to assess the validity of the retractable type of sham needle. METHODS: The authors conducted two randomized, single-blind, crossover trials with acupuncture-experienced subjects. Different acupuncture points were used in each trial (a LI-4 trial and a BL-23 trial). The subjects received two sessions of different stimulations in each trial. A Park Sham Needle was used in one session, a genuine acupuncture needle in the other. RESULTS: In the LI-4 trial, all of the 21 subjects (100%) felt penetration with the genuine needle, but only 7 of the 20 subjects (35%) felt a similar sensation with the sham needle (P=0.0002). Fifteen of the 21 subjects (71%) felt a dull sensation with the genuine needle, but only 4 of the 20 subjects (20%) felt a similar sensation with the sham needle (P=0.01). In the BL-23 trial, 14 of the 20 subjects (70%) felt penetration with the genuine needle and 10 of the 20 subjects (50%) felt "penetration" with the sham needle (P=0.39). Eight of the 20 subjects (40%) felt a dull sensation with the genuine needle and 2 of the 20 subjects (10%) did with the sham needle (P=0.109). CONCLUSIONS: Potential factors that influence the applicability of "placebo" needling include not only inter-tester variability but also the patient's knowledge and experience of acupuncture, acupuncture point selection, the visual impact of needling, and so on.

Acupuncture Therapy↗

PubMed2005

Changes in mental disorder distribution among suicide attempters in mid-west area of Kanagawa.

To clarify changes in mental disorder distribution in suicide attempters, a comparison was made between the period when an economic recession started (1992, 1993) and the period when the recession became serious (2000). The subjects were 212 suicide attempters admitted to the Emergency Medical Center of Tokai University Hospital during a 2-year period between 1992 and 1993 (group A) and 255 suicide attempters admitted during a 1-year period between January and December 2000 (group B). Mental disorders were classified according to the International Classification of Diseases (10th revision; ICD-10). Distribution was compared between groups A and B and significant differences were observed in mental disorder distribution (P < 0.001). The percentages of subjects with depression, those with neurotic disorders, and those with other disorders were higher in group B than in group A. Conversely, the percentage of subjects with schizophrenia was lower in group B than in group A. Mental disorder distribution in suicide attempters significantly changed. However, it was not certain that this change was related to the economic recession and increased unemployment in Japan.

Adult↗

PubMed2005

Computer-assisted measurement of perceived stress: an application for a community-based survey.

The assessment of stress is a key issue in health promotion policies as well as in treatment strategies for patients. The aim of this study was to confirm the accessibility and reliability of computer-assisted data collection for perceived stress measurement, using the Japanese version of the Perceived Stress Scale (JPSS), within the setting of a community-based survey. There were two groups of participants in this survey. One group responded to a Web-based application, and the other to the VBA of a spreadsheet software. The total scores of JPSS were almost normally distributed. The means of total scores of JPSS were 23.6 and 23.1. These results were lower than the previous study of JPSS. Since Cronbach's alpha coefficients in both surveys were more than 0.8, high reliability was demonstrated despite a number of computer-illiterate and/or aged participants. They felt that the spreadsheet form was easier to respond to. Two components were extracted with the Varimax rotation of principal component analysis, and these were named "perception of stress and stressors" and "behavior to stress". This finding suggests that it is possible to determine sub-scales. From the viewpoint of preventive medicine, it is expected that the JPSS applications will be utilized to investigate the relationship between stress and other factors such as lifestyle, environment and quality of life.

Adult↗

PubMed2004

Functional connectivity between forearm and digits representations in human somatosensory area 3b.

OBJECTIVE: We compared the effects of tactile interference to the forearm on magnetic responses evoked by electric stimulation of the little finger (D5) and the thumb (D1). METHODS: Electric stimulation was delivered to D5 or D1 individually. In each stimulus session, magnetic recordings were conducted with or without concurrent tactile interference to the radial side of the anterior forearm. RESULTS: With forearm interference, the amplitude of the primary response (N20m) following D5 stimulation was reduced to 90.7% of the control value without interference, while that following D1 stimulation was not affected (100.7%). CONCLUSIONS: In human somatosensory area 3b, the representation of the forearm is immediately adjacent to that of the D5, and distant from that of the D1. Thus, the result suggests that the tactile interference effect on N20m depends on the cortical distance between electrically and mechanically activated 3b areas. SIGNIFICANCE: Intrinsic synaptic connections between the 3b hand representation and its surroundings have been hypothesized as a neural basis for plastic changes of the human brain, such as a phantom hand phenomenon. The present finding implies that these connections may play some physiological roles even in normal adult humans.

Adult↗

PubMed2004

Is there training-dependent reorganization of digit representations in area 3b of string players?

OBJECTIVE: The digit representations in area 3b were studied to examine whether there is training-dependent reorganization in string players. METHODS: Somatosensory evoked magnetic fields were recorded following electrical stimulation of digits 1 (D1), 2 (D2) and 5 (D5) of both hands in 8 string players and of the left hand in 12 control subjects. The N20m and P30m responses, and high-frequency oscillations (HFOs) were separated by 3-300 Hz and 300-900 Hz bandpass filtering. RESULTS: The dipole locations on the coronal plane and strengths of D1, D2 and D5, and D1-D5 cortical distance estimated at the peak of N20m or P30m did not differ between left and right hand in string players or between left hand in string players and controls. On the other hand, the dipole locations of D2 estimated from N20m and P30m and of D1 from N20m were significantly anterior, the D2-D5 distance from P30m longer, and the number of HFO peaks larger for D5 in string players than controls. CONCLUSIONS/SIGNIFICANCE: With strong mutual competition among the fingering digits, the scale of reorganization should be much smaller as compared with the competition-free denervation-induced reorganizations. Taken together, the training-dependent reorganization of somatosensory cortex in string players is manifest not only in the enlarged cortical representation but also in the enhanced HFOs presumably representing activity of the fast-spiking interneurons.

Adolescent↗

PubMed2004

Association of health-related quality of life with health examination including organic functions and lifestyles in Japanese employees.

OBJECTIVE: The objective of this study was to compare the association of each item of a health examination including organic functions and lifestyles with health-related quality of life (HRQoL) by gender. METHODS: A cross-sectional survey by a self-administered questionnaire using the 36-Item Short Form Health Survey (SF-36) was conducted for Japanese employees from October 1999 to September 2000. Participants in this study consisted of 458 men and 321 women systematically selected from the health examinees. MAIN RESULTS: The determination of organic functions including 'body mass index', 'blood pressure', 'liver functioning', and 'blood sugar control' was hardly associated with HRQoL, except for the body mass index in women. All the lifestyle items including smoking cigarettes, drinking alcohol, eating breakfast, doing exercise, adhering to bedtime, and working overtime were associated with HRQoL in the multiple regression models. In the mental component summary (MCS), the standardized regression coefficient of 'hours of overtime' was -0.235 in the men and -0.212 in the women (p < 0.001). In the physical component summary (PCS), that of 'energy consumed in exercise' was 0.149 in the women (p < 0.01). CONCLUSION: This study reveals that the association between lifestyle and HRQoL was stronger than that between organic function and HRQoL.

Adult↗

PubMed2004

Health-related quality of life in outpatients of a psychosomatic medicine clinic: a pilot survey in Japan.

The objective of this study is to clarify the difference of health-related quality of life (HRQoL) profiles by disease category with the SF-36 questionnaires, and to examine the possibility of application for a longitudinal study. A number of subjects was 536, specifically 127 men and 409 women. For all of the eight domains, Cronbach's alpha exceeded 0.7. Categories in which all of the domains were approximately equal to the national standard included hypertension, neck and shoulders syndrome, diabetes, hyperlipidemia and cardiac disease. Bodily pain was especially lower in gastrointestinal disorder, spondylopathy and hemopathy. Patients with mental disorder had lower scores in all domains. Categories in which 5-7 of the eight domains had lower scores included arthropathy, asthma, chronic hepatitis, autonomic imbalance, 'ovariopathy and hysteropathy' and chronic rheumatism. No significant change was found between the first and second scores in hypertension as a representative of the high HRQoL categories. In mental disorder as a representative of the low HRQoL categories, however, five of the eight domains increased significantly. We concluded that a target disease should be chosen among subjects with low HRQoL scores before an intervention to assess its effectiveness. Or subjects with high HRQoL scores can be examined to determine whether they keep the same level of HRQoL.

Adolescent↗

PubMed2003

Muscle afferent inputs from the hand activate human cerebellum sequentially through parallel and climbing fiber systems.

OBJECTIVE: Spatio-temporal response characteristics of the human cerebellum to median nerve stimulation (MNS) were studied with the use of a whole-head magnetoencephalographic (MEG) system covering the cerebellum and upper cervical spine. METHODS: Neuromagnetic responses from the cerebellum were recorded following electric stimulation of the right median nerve in 12 subjects. In 6 out of 12 subjects, the responses to the left median nerve and to the right index or middle finger stimulation were also recorded. RESULTS: The medial part of the cerebellum (spinocerebellum) was activated by MNS. In contrast, there were no responses from the cerebellum to the finger stimulation, suggesting that muscle afferent inputs are the source of cerebellar activation for MNS. The cerebellar responses consisted of 3 or 4 components of alternating polarity within 90 ms post-stimulus: the current direction for the first component was from the depth to the surface of the anterior lobe. CONCLUSIONS: From the timing and current direction, we speculate that the 4 components reflect, respectively, (1) excitatory postsynaptic potentials (EPSPs) of granule cells, (2) Purkinje cell EPSPs at the distal dendrites driven by parallel fibers, (3) Purkinje cell EPSPs at the soma and the proximal dendrites mediated by climbing fibers and (4) second Purkinje cell EPSPs at the distal dendrites driven by parallel fibers. SIGNIFICANCE: We first visualized serial activation of the human spinocerebellum following MNS noninvasively with MEG.

Adult↗

PubMed2002

Contribution of primary somatosensory area 3b to somatic cognition: a neuromagnetic study.

Interference effects on somatic cognition were compared with those on primary magnetic N20m responses. During tactile interference to various sets of digits, sensory thresholds for electric middle finger stimulation were measured, and then N20m was elicited with the intensity 4 mA above the sensory threshold measured without interference. After the recording, subjective magnitudes for the test stimuli were reported. Modifications of N20m and above psychophysical measures were dependent on the distance between electrically and mechanically activated areas. The differential N20m attenuation is considered to be generated within the neural circuitry in area 3b consisting of mechanically and electrically activated pyramidal neurons. The result indicates that such circuitry plays a fundamental role in magnitude estimation of somatic stimuli.

Adult↗

PubMed2002

Neural mechanisms for generation of tactile interference effects on somatosensory evoked magnetic fields in humans.

OBJECTIVES: We examined modification of somatosensory evoked fields following electric middle finger stimulation with interference to the same and surrounding digits in 13 subjects. METHODS: During electric middle finger stimulation, concurrent tactile stimulation was applied to the middle finger, to the index and ring fingers, and to the thumb and the little finger, individually. RESULTS: The amplitudes of the N20m and the P30m were significantly reduced by the interference to the middle finger, and to the index and ring fingers. The former interference induced more prominent attenuation than the latter. The amplitudes of the P60m did not show significant changes by any kind of the interference. CONCLUSIONS: The N20m and the P30m were attenuated according to the cortical distance between electrically and mechanically activated 3b areas. Pyramidal neurons are interconnected by intrinsic horizontal collaterals, even if their representations are segregated. The activation of the intrinsic collaterals induces direct excitation and indirect inhibition (via inhibitory interneurons) to the target pyramidal neurons. The result indicates that the activation of the intrinsic collaterals inhibits, on balance, the postsynaptic pyramidal targets, thereby generating the attenuation of the N20m and P30m.

Adult↗

PubMed2002

Movement interference attenuates somatosensory high-frequency oscillations: contribution of local axon collaterals of 3b pyramidal neurons.

OBJECTIVES: We examined the effects of movement interference on high-frequency oscillations (HFOs) and N20m in 10 healthy subjects. METHODS: For the movement interference condition, somatosensory evoked magnetic fields (SEFs) following electric median nerve stimulation were recorded during voluntary movement of the digits. For the control condition, the SEFs were recorded without interference. The N20m and HFOs were separated by 3-300Hz and 300-900Hz bandpass filtering. Then, the peak-to-peak amplitudes were measured. RESULTS: Both interference/control amplitude ratios for the N20m and HFOs were smaller than 100%. In contrast, the HFO/N20m amplitude index, which was calculated by dividing the interference/control amplitude ratio for the HFOs with that for the N20m, was significantly greater in the movement interference condition than in the control condition. CONCLUSIONS: Although the overall amplitude of the HFOs was decreased by movement, enhancement of the HFOs by the movement was revealed by the HFO/N20m amplitude index. Thus, we suggest that the HFOs represent activity of the inhibitory interneurons excited by both thalamocortical afferent impulses and excitatory synaptic inputs from pyramidal neurons in area 3b through their local axon collaterals, thereby reflecting both feed-forward and feedback inhibitory effects onto the post-synaptic pyramidal neurons.

Adult↗