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Kiyotaka Suzuki

Publications and source records attributed to Kiyotaka Suzuki.

8 recordsLinked to original sources
PubMed2006

Human primary motor cortex shows hemispheric specialization for speech.

Hemispheric specialization is a prominent characteristic of the human brain. Should the 'dominant' hemisphere possess differential neural organization for language production in the 'higher order' cortex, it would be rational to consider that the primary motor cortex may also show similar hemispheric specialization for speech production. In order to test this hypothesis, we investigated the spatial distribution of neural activities associated with phonation (M1p), silent tongue motion (M1t), and vocalization (M1v) within the primary motor cortex, utilizing independent component-cross correlation-sequential epoch analysis of high-field functional magnetic resonance imaging time series. While M1t showed no significant differences between the two hemispheres, M1p and M1v exhibited significant hemispheric differences. The study demonstrated direct evidence that human primary motor cortex possesses clear-cut hemispheric specialization similar to that observed for the higher order cortices.

Adult↗
PubMed2006

[Study on the number of denture adjustments in complete denture wearers--relationship to mandibular ridge shape].

PURPOSE: This study investigated the relationship between the degree of mandibular alveolar ridge resorption and the number of denture adjustments after insertion of dentures in complete denture wearers. METHODS: The subjects were 77 complete denture patients (34 males, 43 females, mean age 69.1+/-8.1 years). Using bite plates of Gothic arch tracing for new denture production, the width, height, and inclination toward the tentative occlusal plane of the mandibular alveolar ridge corresponding to the canine areas (C), first premolar areas (P1), second premolar areas (P2), and first molar areas (M1) were measured bilaterally, and the relationship with the number of denture adjustment was evaluated. RESULTS: The mean of number of denture adjustments was 4.4+/-1.8 times (male 3.8 times, female 5.0 times), showing a significant difference between males and females (p<0.01). The alveolar ridge mean width was C: 9.7 mm, P1: 10.4 mm, P2: 11.5 mm, and M1: 13.0 mm respectively. The alveolar ridge mean height was C: 4.3 mm, P1: 4.6 mm, P2: 4.9 mm, and M1: 5.2 mm. The alveolar ridge mean inclination was C: 11.2 degrees, P1: 13.5 degrees, P2: 15.4 degrees, and M1: 18.8 degrees. The width and height of the mandibular alveolar ridge in C, P1, P2, and M1 were significantly larger in males than in females (p<0.05). The height of mandibular alveolar ridge was significantly lower in high number of denture adjustment than in low number of denture adjustment (p<0.05). CONCLUSION: Complete denture wearers showed a high relation between the number of denture adjustment and the mandibular alveolar ridge height.

Adult↗
PubMed2004

The primary motor area for voluntary diaphragmatic motion identified by high field fMRI.

In order to identify the precise location of the primary motor area for the diaphragm with respect to the classical motor homunculus, functional magnetic resonance imaging (fMRI) experiments were performed utilizing independent component-cross correlation- sequential epoch (ICS) analysis on a high-field (3.0 Tesla) system. Activations which correlated with voluntary diaphragmatic motion mapped onto the area anterolateral to that for voluntary hand motion (internal control in ICS analysis). Multiple subject analysis yielded the primary motor cortex for the diaphragm to be (+/-48, -4, 47) in the Talairach and Tournoux coordinates. The results were highly consistent with the previously reported cortical area for the diaphragm determined by transcranial electrical/magnetic stimulation.

Adult↗
PubMed2003

All-phase MR angiography using independent component analysis of dynamic contrast enhanced MRI time series: phi-MRA.

Dynamic contrast enhanced magnetic resonance imaging (dynamic MRI) represents a MRI version of non-diffusible tracer methods, the main clinical use of which is the physiological construction of what is conventionally referred to as perfusion images. The raw data utilized for constructing MRI perfusion images are time series of pixel signal alterations associated with the passage of a gadolinium containing contrast agent. Such time series are highly compatible with independent component analysis (ICA), a novel statistical signal processing technique capable of effectively separating a single mixture of multiple signals into their original independent source signals (blind separation). Accordingly, we applied ICA to dynamic MRI time series. The technique was found to be powerful, allowing for hitherto unobtainable assessment of regional cerebral hemodynamics in vivo.

Aged↗
PubMed2003

A novel single-nucleotide substitution, Leu 467 Pro, in the interferon-gamma receptor 1 gene associated with allergic diseases.

We identified a novel heterozygous single-nucleotide substitution 1400 T right curved arrow C (Leu 467 Pro) in the seventh exon of the interferon-gamma receptor 1 (IFNGR1) gene. This substitution was detected in 6 of the 89 allergic patients but not in the 72 non-allergic subjects. There was a difference in the L467P frequency between the allergic patients and the non-allergic subjects (Fisher's exact test: p=0.033). The 6 patients with L467P have allergic diseases such as bronchial asthma and/or allergic rhinitis. Furthermore, a familial analysis for L467P revealed a linkage between allergic diseases and L467P. Serum IgE levels of the patients with L467P were higher than those of the non-allergic subjects (p=0.001). Our previous studies have been shown that interferon-gamma (IFN-gamma) production by PBMCs in the allergic patients was lower than that in the non-allergic subjects. In this study, although IFN-gamma production in the allergic patients with L467P was equivalent to that in the non-allergic subjects, their serum IgE levels were high and they had allergic diseases. Our results suggest that some allergic patients have IFNGR dysfunction, and that L467P in the IFNGR1 gene is one of candidate susceptibility genes for allergic diseases.

Adolescent↗
PubMed2002

Fast and precise independent component analysis for high field fMRI time series tailored using prior information on spatiotemporal structure.

Independent component analysis (ICA) has been shown as a promising tool for the analysis of functional magnetic resonance imaging (fMRI) time series. Each of these studies, however, used a general-purpose algorithm for performing ICA and the computational efficiency and accuracy of elicited neuronal activations have not been discussed in much detail. We have previously proposed a direct search method for improving computational efficiency. The method, which is based on independent component-cross correlation-sequential epoch (ICS) analysis, utilizes a form of the fixed-point ICA algorithm and considerably reduces the time required for extracting desired components. At the same time, it is shown that the accuracy of detecting physiologically meaningful components is much improved by tailoring the contrast function used in the algorithm. In this study, further improvement was made to this direct search method by integrating an optimal contrast function. Functional resolution of activation maps could be controlled with a suitable selection of the contrast function derived from prior knowledge of the spatial patterns of physiologically desired components. A simple skewness-weighted contrast function was verified to extract sufficiently precise activation maps from the fMRI time series acquired using a 3.0 Tesla MRI system.

Adolescent↗
PubMed2002

[Evaluation before and after pranlukast administration with the QOL questionnaire (revised version 2001) for pediatric patients with bronchial asthma and their parents or caregivers].

We conducted a longitudinal investigation with the QOL questionnaire (revised version 2001) before and after the 4-week-administration of a leukotriene receptor antagonist pranlukast. A significant improvement in the < 4 yrs group was observed at week 1, and that in > or = 4 yrs group at week 2. Under these conditions, the overall QOL score, physical domains and mental domains, significantly improved in both the < 4 yrs group and the > or = 4 yrs group. Overall, a slight correlation was observed between ratio changes in QOL scores and differences in symptom scores. However, no correlation was found in part of patients, suggesting that the QOL questionnaire allows measurement of mental changes in the patients themselves and their parents or caregivers for therapeutic effects which cannot be determined with ordinary physical findings only. In "event present" group, a significant difference in physical and mental domains was revealed by the comparison of QOL scores before and after administration. And furthermore in "event absence" group, the p-value for physical domain and mental domain was 0.0505 and 0.0912 in the < 4 yrs group, respectively, 0.0101 and 0.0446 in the > or = 4 yrs group, respectively. The above results led us to consider the QOL questionnaire (revised version 2001) useful for routine medical care. Furthermore, pranlukast was considered useful for improvement not only of physical symptoms of bronchial asthma but also of the patient's QOL, although the placebo effects in this open trial must be considered.

Anti-Asthmatic Agents↗