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Shigeru Sato

Publications and source records attributed to Shigeru Sato.

At least 19 recordsLinked to original sources
PubMed2007

Effect of syntactic similarity on cortical activation during second language processing: a comparison of English and Japanese among native Korean trilinguals.

In this study of native Korean trilinguals we examined the effect of syntactic similarity between first (L1) and second (L2) languages on cortical activation during the processing of Japanese and English, which are, respectively, very similar to and different from Korean. Subjects had equivalent proficiency in Japanese and English. They performed auditory sentence comprehension tasks in Korean, Japanese, and English during functional MRI (fMRI). The bilateral superior temporal cortex was activated during the comprehension of three languages. The pars triangularis of the left inferior frontal gyrus (IFG) was additionally activated for L2 processing. Furthermore, the right cerebellum, the pars opercularis of the left IFG, and the posteriomedial part of the superior frontal gyrus were activated during the English tasks only. We observed significantly greater activation in the pars opercularis of the left IFG, the right cerebellum, and the right superior temporal cortex during the English than Japanese task; activation in these regions did not differ significantly between Korean and Japanese. Differential activation of the pars opercularis of the left IFG and the right cerebellum likely reflects syntactic distance and differential activation in the right superior temporal cortex may reflect the prosodic distance between English from Korean and Japanese. Furthermore, in the pars oparcularis of the left IFG and the right cerebellum, significant negative correlation between the activation and duration of exposure was observed for English, but not for Japanese. Our research supports the notion that linguistic similarity between L1 and L2 affects the cortical processing of second language.

Acoustic Stimulation↗
PubMed2006

Is Broca's area involved in the processing of passive sentences? An event-related fMRI study.

We used functional magnetic resonance imaging (fMRI) to investigate whether activation in Broca's area is greater during the processing of passive versus active sentences in the brains of healthy subjects. Twenty Japanese native speakers performed a visual sentence comprehension task in which they were asked to read a visually presented sentence and to identify the agent or the patient in the sentence by pressing a button. We found that the processing of passive sentences elicited no greater activation than that of active sentences in Broca's area. However, passive sentences elicited greater activation than active sentences in the left frontal operculum and the inferior parietal lobule. Thus, our neuroimaging results suggest that deficits in the comprehension of passive sentences in Japanese aphasics are induced not by lesions to Broca's area, but to the left frontal operculum and/or the inferior parietal lobule.

Adolescent↗
PubMed2006

Evaluation of metabolic alteration in transgenic rice overexpressing dihydroflavonol-4-reductase.

BACKGROUND AND AIMS: Previous studies have shown that transgenic rice plants overexpressing YK1, which possesses dihydroflavonol-4-reductase (DFR) activity, showed biotic and abiotic stress tolerance. High throughput profiles of metabolites have also been shown in such transgenic plants by Fourier transform ion cyclotron mass spectrometry. In this study, capillary electrophoresis mass spectrometry analysis (CE/MS) was employed to identify precise metabolites such as organic acids, amino acids and sugars. METHODS: Using CE/MS, we analysed several metabolites of glycolysis, the tricarboxylic acid (TCA) cycle and the pentose phosphate pathway. In addition, the concentrations of sugars and ion were quantified. KEY RESULTS: In YK1 (DFR)-overexpressing plants, the concentrations of cis-aconitate, isocitrate and 2-oxoglutarate were higher in leaves, whereas those of fructose-1,6-bisphosphate and glyceraldehyde-3-phosphate were lower in roots. In seeds, the amounts of free amino acids and metals were altered, whereas sugars in seeds were kept constant. In YK1 calli, an approx. 3-fold increase in glutathione was observed, whereas the activities of glutathione peroxidase and glutathione reductase were concomitantly increased. CONCLUSIONS: The overexpression of YK1 (DFR) was associated with slight changes in the amounts of several metabolites analysed in whole plants, whilst glutathione derivatives were substantially increased in suspension-cultured cells.

Alcohol Oxidoreductases↗
PubMed2006

MRI findings from a case of fulminating adult-onset measles encephalitis.

We report a rare case of fulminating adult-onset measles encephalitis. A 34-year-old man developed a comatose state after measles eruptions and ultimately akinetic mutism. Titers of anti-measles IgM antibodies were elevated in both serum and cerebrospinal fluid. Brain magnetic resonance imaging (MRI) 3 months after onset revealed widespread hyperintense lesions in the periventricular white matter and marginal hyperintense lesions in the brainstem on fluid-attenuated inversion recovery and diffusion-weighted images. The marginal lesions in the brainstem are similar to subpial demyelinating lesions seen in postinfectious encephalomyelitis. This case of encephalitis may be related to an autoimmune-mediated process triggered by measles infection.

Adult↗
PubMed2006

Multiple brain networks for visual self-recognition with different sensitivity for motion and body part.

Multiple brain networks may support visual self-recognition. It has been hypothesized that the left ventral occipito-temporal cortex processes one's own face as a symbol, and the right parieto-frontal network processes self-image in association with motion-action contingency. Using functional magnetic resonance imaging, we first tested these hypotheses based on the prediction that these networks preferentially respond to a static self-face and to moving one's whole body, respectively. Brain activation specifically related to self-image during familiarity judgment was compared across four stimulus conditions comprising a two factorial design: factor Motion contrasted picture (Picture) and movie (Movie), and factor Body part a face (Face) and whole body (Body). Second, we attempted to segregate self-specific networks using a principal component analysis (PCA), assuming an independent pattern of inter-subject variability in activation over the four stimulus conditions in each network. The bilateral ventral occipito-temporal and the right parietal and frontal cortices exhibited self-specific activation. The left ventral occipito-temporal cortex exhibited greater self-specific activation for Face than for Body, in Picture, consistent with the prediction for this region. The activation profiles of the right parietal and frontal cortices did not show preference for Movie Body predicted by the assumed roles of these regions. The PCA extracted two cortical networks, one with its peaks in the right posterior, and another in frontal cortices; their possible roles in visuo-spatial and conceptual self-representations, respectively, were suggested by previous findings. The results thus supported and provided evidence of multiple brain networks for visual self-recognition.

Adolescent↗
PubMed2006

Remarkable difference in accumulation of paralytic shellfish poisoning toxins among bivalve species exposed to Pyrodinium bahamense var. compressum bloom in Masinloc Bay, Philippines.

Seasonal variation of bivalve toxicity was monitored in association with the abundance of the toxic dinoflagellate Pyrodinium bahamense var. compressum in Masinloc Bay, Luzon Island. Among 7 species of bivalve, 6 species became toxic during a bloom of the dinoflagellate. However, remarkable difference in the toxicity was observed among the species. The toxicity of thorny oyster Spondylus squamosus was the highest among the species, showing more than 30 times that of safety consumption level after the peak bloom of the dinoflagellate, while other bivalve species showed much lower toxicity. The toxicity of thorny oyster decreased under absence of the dinoflagellate, but this species maintained a considerably high toxicity throughout a year. Similar trend was observed in penshell Atrina vexillum in a small scale, indicating that these species in the bay are not safe for human consumption almost throughout a year. The toxicity of green mussel Perna viridis increased to significant level during a bloom, but it decreased rapidly when the dinoflagellate disappeared. Toxin analysis of cultured and natural cells showed typical toxin profile of the dinoflagellate. Toxin profile of all the bivalve species reflected the characteristic toxin profile of the dinoflagellate.

Animals↗
PubMed2006

Cortical mechanisms involved in the processing of verbs: an fMRI study.

In this study, we investigated two aspects of verb processing: first, whether verbs are processed differently from nouns; and second, how verbal morphology is processed. For this purpose, we used functional magnetic resonance imaging to compare three types of lexical processing in Japanese: the processing of nouns, unmarked active verbs, and inflected passive verbs. Twenty-eight healthy subjects were shown a lexical item and asked to judge whether the presented item was a legal word. Although all three conditions activated the bilateral inferior frontal, occipital, the left middle, and inferior temporal cortices, we found differences in the degree of activation for each condition. Verbs elicited greater activation in the left middle temporal gyrus than nouns, and inflected verbs showed greater activation in the left inferior frontal gyrus than unmarked verbs. This study demonstrates that although verbs are basically processed in the same cortical network as nouns, nouns and verbs elicit different degrees of activation due to the cognitive demands involved in lexical semantic processing. Furthermore, this study also shows that the left inferior frontal cortex is related to the processing of verbal inflectional morphology.

Adult↗
PubMed2006

Light-emitting diode phototherapy at 630 +/- 3 nm increases local levels of skin-homing T-cells in human subjects.

BACKGROUND AND AIMS: Red light phototherapy with laser sources has been used successfully for a number of indications. A new generation of quasimonochromatic 630 +/- 3 nm light-emitting diode (LED) systems has recently been yielding good results for the same indications, but no study has examined changes in visible red light irradiated skin at an immunological level. This study was thus designed to examine changes in skin-homing T-cell levels induced in normal human skin by visible red LED energy. SUBJECTS AND METHODS: Six adult male volunteers (35 approximately 48 years old) who satisfied all study criteria had the skin over the lateral aspect of the leg irradiated once per week for 8 weeks with a visible red (630 +/- 3 nm) LED-based system, with irradiance of 105 m/cm2, 15 minutes/session, and a radiant flux of 94 J/cm2. Skin biopsies were performed after the eighth treatment session, and cultures were prepared to assay the type and quantity of skin-homing T-cells using qualitative and quantitative polymerase chain reaction (PCR) techniques. Ultrastructural changes were also assessed with transmission electron microscopy. RESULTS: Transmission electron microscopy revealed mild fibroplastic changes in fibroblasts, with no acute inflammatory changes throughout the treatment session. Qualitative PCR showed the presence of both Th-1 and Th-2 T-cells, and quantitative PCR showed an increase in the numbers of both types of skin-homing T-cells, much more so for Th-2 than for Th-1. CONCLUSIONS: Visible red LED irradiation appears to activate the skin-homing immune system.

Adult↗
PubMed2006

Comparison of two different nutritive conditions against the changes in peripheral blood mononuclear cells of periparturient dairy cows.

To clarify the relationship between cellular immune status and nutritive condition in periparturient dairy cows, feeding content, blood profiles, and immune condition were observed in cows from two dairy herds with different types of feed content. Immunological analyses such as leukocyte population and peripheral blood mononuclear cell (PBMC) mRNA of IFN-gamma, TNF-alpha, IL-4, and IL-10, quantified by real-time RT-PCR were performed. With regard to feed content during dry periods, there were six cows in the herd with insufficient non-structural carbohydrate (NFC) intake (group I) and six cows in the herd with sufficient NFC intake (group II). Significantly lower levels of blood glucose were observed in group I between weeks -12 and 16 compared with group II. Serum cholesterol level was significantly lower in group I between weeks 2 and 10 than in group II. The numbers of CD3+ and CD4+ T cells in group I were significantly lower than those in group II in weeks 6 and 14. The numbers of CD21+ B cells were significantly lower in group I than in group II in weeks -16, -12, 2, and 10. On the other hand, the CD4+/CD8+ ratio in group II was significantly higher than group I between weeks 2 and 14. The IFNgamma/IL-4 mRNA rate in group I was significantly lower than group II in week 6. We concluded that cellular immune depression occurrs after calving in dairy cows with low nutritional status in the periparturient period.

Animal Feed↗
PubMed2006

Comparison of the insulin reaction of peripheral blood T cells between healthy Holstein dairy cows and JB during the periparturient period.

To compare the changes in the insulin reaction of Holstein dairy cows and Japanese Black cows (JB) during the periparturient period, the insulin resistance test in vivo and lymphocytes proliferation with insulin in vitro were performed. Ten healthy Holstein dairy cows (Holstein group) and 10 healthy JB cows (JB group) used in this study were observed on days 60, 40, and 20 before calving and days 7 and 20 after calving. In insulin resistance reaction in vivo and in vitro, a low insulin-stimulated glucose disposal rate and lymphocyte proliferation with insulin were observed in the Holstein group compared with the JB group during the experimental period. An analysis of the lymphocytes cultured with insulin showed that the percentage of CD4+CD45R- T cells in the Holstein group was significantly lower than that of the JB group before day 20. These findings indicate that T cells reaction to insulin in healthy periparturient Holstein cows is lower than that in Japanese Black.

Animals↗
PubMed2005

Bone marrow-derived myocyte-like cells and regulation of repair-related cytokines after bone marrow cell transplantation.

OBJECTIVE: Whether bone marrow cells injected following acute myocardial infarction (MI) transdifferentiate into cardiomyocytes remains controversial, and how these cells affect repair-related cytokines is not known. METHODS: Autologous bone marrow-derived mononuclear cells (BM-MNCs) labeled with DiI, 1,1'-dioctadecyl-1 to 3,3,3',3'-tetramethylindocarbocyanine perchlorate, or saline were intravenously injected into rabbits 5 h following a 30-min ischemia and reperfusion protocol, and cardiac function and the general pathology of the infarcted heart were followed up 1 and 3 months post-MI. To search for regenerated myocardium, electron microscopy as well as confocal microscopy were performed in the infarcted myocardium 7 days post-MI. Expression levels of repair-related cytokines were evaluated by immunohistochemistry and Western blotting. RESULTS: Improvements in cardiac function and reductions in infarct size were observed in the BM-MNC group 1 month and 3 months post-MI. Using electron microscopy 7 days after infarction, clusters of very immature (fetal) and relatively mature cardiomyocytes undergoing differentiation were identified in the infarcted anterior LV wall in the BM-MNC group, though their numbers were small. These cells contained many small and dense DiI particles (a BM-MNC marker), indicating that cardiomyocytes had regenerated from the injected BM-MNCs. The expression of both transforming growth factor-beta, which stimulates collagen synthesis and matrix metalloproteinase-1, a collagenase, were both down-regulated 7 days and 1 month post-MI in the BM-MNC group. Stromal cell-derived factor-1, which is known to recruit BM-MNCs into target tissues, was overexpressed in the infarcted areas of BM-MNC hearts 7 days post-MI. CONCLUSIONS: Intravenous transplantation of BM-MNCs leads to the development of BM-MNC-derived myocyte-like cells and regulates the expression of repair-related cytokines that facilitate repair following myocardial infarction.

Animals↗
PubMed2005

Cortical activation in the processing of passive sentences in L1 and L2: an fMRI study.

The question of whether the bilingual brain processes a first and second language (L1 and L2, respectively) differently is a central issue in many psycholinguistic and neurolinguistic studies. This study used functional magnetic resonance imaging (fMRI) to investigate whether late bilinguals process structurally complex sentences in L1 and L2 in different cortical networks. For this purpose, we directly compared brain activity during the processing of active and passive sentences in both L1 and L2. We asked 36 healthy subjects to judge whether or not a presented sentence was semantically plausible. Both L1 and L2 activated the left hemispheric language-related regions such as the left inferior frontal, superior/middle temporal, and parietal cortices. However, we found different activation patterns between L1 and L2 in the processing of passive sentences. Passive sentences elicited greater activation than their active counterparts in the left pars triangularis, the premotor area, and the superior parietal lobule in Japanese, but not in English. Furthermore, there was a significant interaction between sentence type (active versus passive) and language (Japanese versus English) in the left pars orbitalis. The results of this study indicate that late bilinguals use similar cortical regions to comprehend both L1 and L2. However, when late bilinguals are presented with structurally complex sentences, the involvement of these regions differs between L1 and L2. These results suggest that, in addition to age of L2 acquisition and L2 proficiency, differences in grammatical construction affect cortical representation during the comprehension of L1 and L2.

Adult↗
PubMed2005

Brain activation during the course of sentence comprehension.

The purpose of this study is to determine, by functional magnetic resonance imaging, how the activated regions of the brain change as a Japanese sentence is presented in a grammatically correct order. In this study, we presented constituents of a sentence to Japanese participants one by one at regular intervals. The results showed that the left lingual gyrus was significantly activated at the beginning of the sentence, then the left inferior frontal gyrus and left supplementary motor area, in the middle of the sentence, and the left inferior temporal gyrus, at the end of the sentence. We suggest that these brain areas are involved in sentence comprehension in this temporal order.

Adolescent↗
PubMed2005

Production of isodomoic acids A and B as major toxin components of a pennate diatom Nitzschia navis-varingica.

In order to obtain more detailed information on the distribution of domoic acid-producing Nitzschia in Asian waters, Nitzschia-like diatoms were isolated primarily from the Philippines and established in culture for analysis by HPLC with fluorescence detection. Out of 58 isolates, 35 Nitzschia-like diatoms from the estuary areas of San Pedro Bay, Tacloban City and Manila Bay showed significant levels of domoic acid production (1.3-5.6pg/cell). These were identified as Nitzschia navis-varingica. Two isolates from the same locality did not produce domoic acid. Of the 21 isolates from Bulacan Estuary, Manila Bay, none produced domoic acid. They did, however, produce two substances that seemed to be domoic acid derivatives. One of the strains was mass cultured and the substances were extracted, purified and analyzed by LC-MS/MS, proton and (13)C NMR, and UV spectra. The produced substances were determined as isodomoic acids A and B. This is the first report of a diatom that produces isodomoic acids A and B as major toxin components.

Chromatography, High Pressure Liquid↗
PubMed2005

Regulation of melanoblast and retinal pigment epithelium development by Xenopus laevis Mitf.

Mitf is a central regulator of pigment cell development that is essential for the normal development of the melanocyte and retinal pigment epithelium (RPE) lineages. To understand better the role of Mitf, we have used the Xenopus laevis experimental system to allow a rapid examination of the role of Mitf in vivo. Here, we report the function of XlMitfalpha-M on melanophore development and melanization compared with that of Slug that is expressed in neural crest cells. Overexpression of XlMitfalpha-M led to an increase in melanophores that was partly contributed by an increase in Slug-positive cells, indicating that XlMitfalpha-M is a key regulator of melanocyte/melanophore development and melanization. Moreover, overexpression of a dominant-negative form of XlMitfalpha led to a decrease in the number of melanophores and induced abnormal melanoblast migration. We also observed an induction of ectopic RPE and extended RPE by overexpression of XlMitfalpha-M and possible interactions between XlMitfalpha and several eye-related genes essential for normal eye development.

Amino Acid Sequence↗