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Biomedical subjects

Michio Suzuki

Publications and source records attributed to Michio Suzuki.

At least 19 recordsLinked to original sources
PubMed2026

Quantitative Proteomic Profiling of Pinctada fucata Shell Nacre Defines a Solubility-Based Type Classification of Shell Matrix Proteins.

Shell matrix proteins (SMPs) are key organic components of molluscan biominerals, yet previous nacre proteomics have remained largely qualitative, limiting evaluation of the abundance and fraction association of individual SMPs. Here, we established a quantitative proteomic approach for the nacreous layer of the pearl oyster Pinctada fucata by integrating optimized shell preservation, stepwise fractionation, and data-independent acquisition (DIA) proteomics. SMPs were separated into an ethylenediaminetetraacetic acid (EDTA)-soluble matrix (ESM), an EDTA-insoluble but sodium dodecyl sulfate/dithiothreitol (SDS/DTT)-soluble matrix (SSM), and an SDS/DTT-insoluble matrix (ISM). DIA outperformed data-dependent acquisition in proteome coverage and enabled quantification of 327 SMPs across a broad dynamic range. Fraction-resolved abundance profiling showed that each fraction was characterized by distinct SMP compositions. To summarize these distributions, we introduced a solubility-based type classification that grouped SMPs into four types according to their quantitative partitioning among fractions. Well-known SMPs, including nacrein, Pif 80, and MSI60, were assigned to intuitively consistent types, whereas proteases, protease inhibitors, and tyrosinases also showed biased type distributions. These results support a three-compartment model of the nacreous layer consisting of (i) an insoluble interlamellar membrane core, (ii) a relatively extractable interfacial layer, and (iii) a soluble matrix fraction enriched in proteins potentially involved in ionic regulation and protein maturation. This study provides a quantitative framework for understanding coordinated SMP functions during nacre formation and for comparative analyses of molluscan shell proteomes.

Animals↗
PubMed2005

Differential contributions of prefrontal and temporolimbic pathology to mechanisms of psychosis.

Common abnormalities within the schizophrenia spectrum may be essential for the pathogenesis of schizophrenia, but additional pathological changes may be required for the development of full-blown schizophrenia. Clarifying the neurobiological similarities and differences between established schizophrenia and a milder form of schizophrenia spectrum disorder would potentially discriminate the pathophysiological mechanisms underlying the core features of the schizophrenia spectrum from those associated with overt psychosis. High-resolution MRIs were acquired from 25 patients with schizotypal disorder, 53 patients with schizophrenia and 59 healthy volunteers matched for age, gender, handedness and parental education. Volumetric measurements of the medial temporal structures and the prefrontal cortex subcomponents were performed using consecutive 1-mm thick coronal slices. Parcellation of the prefrontal cortex into subcomponents was performed according to the intrinsic anatomical landmarks of the frontal sulci/gyri. Compared with the controls, the bilateral volumes of the amygdala and the hippocampus were reduced comparably in the schizotypal and schizophrenia patients. The parahippocampal gyrus volume did not differ significantly between diagnostic groups. Total prefrontal grey matter volumes were smaller bilaterally in the schizophrenia patients than in the controls and the schizotypal patients, whereas the schizotypal patients had larger prefrontal grey matter than the controls in the right hemisphere. In the schizophrenia patients, grey matter volumes of the bilateral superior frontal gyrus, left middle frontal gyrus, bilateral inferior frontal gyrus and bilateral straight gyrus were smaller than those in the controls. The schizophrenia patients also had reduced grey matter volumes in the right superior frontal gyrus, bilateral middle frontal gyrus and right inferior frontal gyrus relative to the schizotypal patients. Compared with the controls, the schizotypal patients had larger volumes of the bilateral middle frontal gyrus and smaller volumes of the right straight gyrus. There were no significant between-group differences in volumes of the ventral medial prefrontal cortex or the orbitofrontal cortex. These findings suggest that volume reductions in the amygdala and hippocampus are the common morphological substrates for the schizophrenia spectrum, which presumably represent the vulnerability. Additional widespread involvement of the prefrontal cortex in schizophrenia may lead to the loss of inhibitory control in other brain regions and suggests (although it is not specifically be related to) its critical role in the manifestation of overt psychosis.

Adult↗
PubMed2005

Volumetric MRI study of the short and long insular cortices in schizophrenia spectrum disorders.

We have previously reported volume reductions of the insular cortex in schizophrenia, but it is still not clear whether insular cortex volume loss preferentially involves the anterior (short insular cortex) or posterior (long insular cortex) portion. On the other hand, no volumetric studies of the brain have examined changes in insular cortex volume in subjects with schizotypal features. In this study, we separately investigated the volumes of the short and long insular cortex portions using magnetic resonance imaging in 37 schizotypal disorder patients (24 males, 13 females), 62 schizophrenia patients (32 males, 30 females), and 69 healthy controls (35 males, 34 females). While the volumes of the short and long insular cortex were significantly reduced in schizophrenia patients compared with schizotypal disorder patients and control subjects, there was no difference between schizotypal disorder patients and control subjects. These results suggest that the volume reduction of the insular cortex may be specific to overt schizophrenia without topographically specific localization.

Adolescent↗
PubMed2004

Bilateral volume reduction of the insular cortex in patients with schizophrenia: a volumetric MRI Study.

The morphologic changes of the insular cortex have been described in schizophrenia, but with inconsistencies between reports. We investigated the insular cortex volume by magnetic resonance imaging in 59 schizophrenia patients (31 males, 28 females) and 62 age- and gender-matched healthy controls (31 males, 31 females). The insular cortex volume was measured on consecutive coronal 1-mm slices. Volumes of the left and right insular cortex were significantly reduced in schizophrenia patients compared with control subjects. There were no effects of gender on the insular cortex volume in the patient group or control subjects. Bilateral insular cortex volumes were correlated negatively with illness duration in the patient group. The findings of this study suggest that there is a possible progressive loss of the gray matter volume of the bilateral insular cortices subsequent to the onset of schizophrenia.

Adolescent↗
PubMed2004

Volume reduction of the amygdala in patients with schizophrenia: a magnetic resonance imaging study.

The amygdala is known to be involved in the pathology of schizophrenia. While only a limited number of studies in schizophrenia have measured the amygdala as a single structure. The aim of this study was to examine the hypothesis that patients with schizophrenia would show reduced volumes in the amygdala compared with normal controls. We investigated amygdala volume in 40 patients with schizophrenia (20 males, 20 females) and 40 age- and gender-matched normal controls using three-dimensional magnetic resonance imaging (MRI). Whole volumes of both the amygdala and the temporal lobe were measured on consecutive coronal 1-mm slices. The amygdala volume was significantly smaller in schizophrenia patients than in controls. Considering gender differences, male patients had significantly smaller volumes in the bilateral amygdala than male controls; female patients had a significantly reduced right amygdala compared with female controls. Furthermore, a significant left-smaller-than-right volumetric asymmetry of the amygdala was detected in male patients with schizophrenia. The results may be important for understanding the role of the amygdala in the pathophysiology of schizophrenia and the anatomical substrates of gender difference in the expressions of the illness.

Adult↗
PubMed2004

Structural brain differences in patients with schizophrenia and schizotypal disorder demonstrated by voxel-based morphometry.

Brain abnormalities of schizophrenia probably consist of deviation related to the vulnerability and pathological changes in association with overt psychosis. We conducted a cross-sectional comparison in brain morphology between patients with overt schizophrenia and schizotypal disorder, a schizophrenia-spectrum disorder without florid psychotic episode. Voxelbased morphometry was applied to assess gray matter volume in 25 patients with schizophrenia, 25 patients with schizotypal disorder, and 50 healthy control subjects. In comparison with controls, schizophrenia patients showed gray matter reductions in the bilateral medial frontal, inferior frontal, medial temporal, and septal regions, and the left middle frontal, orbitofrontal, insula, and superior temporal regions, and an increased gray matter in the left basal ganglia. Schizotypal disorder patients showed reductions in the left inferior frontal, insula, superior temporal, and medial temporal regions. There was a significant reduction in the left orbitofrontal region of schizophrenia compared with schizotypal disorder. Gray matter reductions that are common to both patient groups such as those in the left medial temporal and inferior frontal regions may represent vulnerability to schizophrenia, and additional involvement of several frontal regions may be crucial to florid psychosis.

Adolescent↗
PubMed2004

Relationship between exploratory eye movements and brain morphology in schizophrenia spectrum patients: voxel-based morphometry of three-dimensional magnetic resonance imaging.

The exploratory eye movements of schizophrenia patients and their relatives have been shown to differ from those of patients without schizophrenia and healthy controls. However the mechanism of exploratory eye movement disturbances in schizophrenia patients remains elusive. We investigated the relationship between the exploratory eye movements and brain morphology in 39 schizophrenia spectrum patients. Voxel-based morphometric analysis on three-dimensional magnetic resonance imaging was conducted by means of statistical parametric mapping 99. The decrease in the responsive search score, which is the total number of sections on which the eyes fixed in response to questioning in a comparison task, was significantly correlated with the decreased gray matter in the right frontal eye field (rFEF) including the right supplementary eye field (rSEF), right parietal eye field (rPEF), and right inferior frontal region. These results suggest that disturbance in exploratory eye movement in schizophrenia spectrum patients may be related to neural network dysfunction in FEF, SEF and PEF, which are the eye movement related areas, and in the inferior frontal region that may be related to information organization.

Adult↗
PubMed2004

Bilateral volume reduction of the insular cortex in patients with schizophrenia: a volumetric MRI study.

The morphologic changes of the insular cortex have been described in schizophrenia, but with inconsistencies between reports. We investigated the insular cortex volume by magnetic resonance imaging in 59 schizophrenia patients (31 males, 28 females) and 62 age- and gender-matched healthy controls (31 males, 31 females). The insular cortex volume was measured on consecutive coronal 1-mm slices. Volumes of the left and right insular cortex were significantly reduced in schizophrenia patients compared with control subjects. There were no effects of gender on the insular cortex volume in the patient group or control subjects. Bilateral insular cortex volumes were correlated negatively with illness duration in the patient group. The findings of this study suggest that there is a possible progressive loss of the gray matter volume of the bilateral insular cortices subsequent to the onset of schizophrenia.

Adolescent↗
PubMed2004

Characterization of Prismalin-14, a novel matrix protein from the prismatic layer of the Japanese pearl oyster (Pinctada fucata).

The mollusc shell is a hard tissue consisting of calcium carbonate and organic matrices. The organic matrices are believed to play important roles in shell formation. In the present study, we extracted and purified a novel matrix protein, named Prismalin-14, from the acid-insoluble fraction of the prismatic layer of the shell of the Japanese pearl oyster (Pinctada fucata), and determined its whole amino acid sequence by a combination of amino acid sequence analysis and MS analysis of the intact protein and its enzymic digests. Prismalin-14 consisted of 105 amino acid residues, including PIYR repeats, a Gly/Tyr-rich region and N- and C-terminal Asp-rich regions. Prismalin-14 showed inhibitory activity on calcium carbonate precipitation and calcium-binding activity in vitro. The scanning electron microscopy images revealed that Prismalin-14 affected the crystallization of calcium carbonate in vitro. A cDNA encoding Prismalin-14 was cloned and its expression was analysed. The amino acid sequence deduced from the nucleotide sequence of Prismalin-14 cDNA was identical with that determined by peptide sequencing. Northern-blot analysis showed that a Prismalin-14 mRNA was expressed only at the mantle edge. In situ hybridization demonstrated that a Prismalin-14 mRNA was expressed strongly in the inner side of the outer fold of the mantle. These results suggest that Prismalin-14 is a framework protein that plays an important role in the regulation of calcification of the prismatic layer of the shell.

Amino Acid Sequence↗
PubMed2004

Male-specific volume expansion of the human hippocampus during adolescence.

To clarify the developmental brain changes during adolescence, brain morphology was compared between healthy younger adolescent and elder adolescent subjects using both voxel-based morphometry (VBM) and volumetric region-of-interest (ROI) analysis of magnetic resonance imaging (MRI). High-resolution three-dimensional MRI scans were acquired in 23 (10 males and 13 females) younger adolescent subjects (13-14 years) and 30 (15 males and 15 females) elder adolescent subjects (19-21 years). Whole-brain analysis by VBM revealed that the elder adolescent subjects had significantly more gray matter in the left medial temporal regions than the younger adolescent subjects and significantly less gray matter in the left medial frontal region (Brodmann area 6). In the volumetric analysis, significantly less cerebral gray matter volume and significantly greater cerebral white matter volume were found in elder adolescents compared with younger adolescents. The volume of the hippocampus was significantly larger in male elder adolescents than in male younger adolescents. The volume of the parahippocampal gyrus did not differ between younger and elder adolescent subjects. These results suggest a robust maturational process ongoing in the human hippocampus during adolescence, especially in males. The possible relevance of these findings to progress in myelination and implications in psychiatric disorders were discussed.

Adolescent↗
PubMed2004

Volume reduction of the right anterior limb of the internal capsule in patients with schizotypal disorder.

We have previously reported bilateral volume reductions in the anterior limb of the internal capsule (ALIC) in patients with schizophrenia. The purpose of this study was to extend the volumetric measurements of ALIC to subjects with schizotypal features to explore the neurobiology underlying schizophrenia-spectrum disorders in view of the fronto-thalamic connectivity. Three-dimensional magnetic resonance images were acquired from 24 patients with schizotypal disorder (ICD-10) and 47 healthy volunteers matched for age, gender, handedness, and parental education. Volumetric analyses of the ALIC and anterior parts of the caudate and lentiform nuclei were conducted using consecutive 1-mm thick coronal slices rostral to the anterior commissure. Compared with the comparison subjects, the schizotypal patients had significantly decreased volume in the right ALIC, but there was no significant group difference in the left ALIC volume. Volumes of the anterior part of the caudate or lentiform nucleus did not differ between groups. Volume deficit confined to the right ALIC suggests that limited involvement of the fronto-thalamic connectivity may have some relevance to the sparing of schizotypal patients from the development of overt psychosis.

Adult↗
PubMed2004

Lack of normal gender differences of the perigenual cingulate gyrus in schizophrenia spectrum disorders. A magnetic resonance imaging study.

We have previously reported a lack of normal gender differences of the perigenual cingulate gyrus in patients with schizophrenia. The purpose of this study was to examine the perigenual cingulate gyrus morphology in patients with schizotypal disorder. We investigated volume of the gray and white matter of the perigenual cingulate gyrus in 26 patients with schizotypal disorder (14 males, 12 females) in comparison with 61 age- and gender-matched healthy controls (30 males, 31 females) and 58 schizophrenia patients (31 males, 27 females) using magnetic resonance imaging. The volumetric measures of the perigenual cingulate gyrus were compared among the three groups that were entered into the same multiple analysis of variance model. The gray and white matter volume of the perigenual cingulate gyrus in the schizotypal patients did not differ significantly from the values in the healthy controls or the schizophrenia patients. Similar to schizophrenia, however, the schizotypal patients showed a lack of normal gender differences of the perigenual cingulate gray matter seen in the healthy controls (females > males). These results suggest that both schizotypal and schizophrenia patients may share the same disruption of the normal pattern of gender differences of the perigenual cingulate gyrus.

Adolescent↗
PubMed2004

Multiple structural brain measures obtained by three-dimensional magnetic resonance imaging to distinguish between schizophrenia patients and normal subjects.

This study was designed to investigate the extent to which schizophrenia patients can be differentiated from normal subjects by structural brain measures. High-resolution magnetic resonance imaging scans were performed on 57 schizophrenia patients (30 males, 27 females) and 47 normal controls (25 males, 22 females). Significant enlargements of the left and right body of the lateral ventricle, the left and right sylvian fissure, and the third ventricle were observed in the male patients. Significant enlargements of the left inferior horn, and the left and right sylvian fissure, and a significant volume reduction of the right temporal lobe were observed in the female patients. Discriminant function analysis using brain anatomical measures as variables allowed correct classification of 80.0 percent of the male patients, 80.0 percent of the male controls, 77.8 percent of the female patients, and 86.4 percent of the female controls. These findings support the view that schizophrenia patients have structural deviations in multiple brain areas and that a combination of structural brain measures can distinguish between patients and controls.

Adolescent↗
PubMed2003

Subchronic phencyclidine administration alters central vasopressin receptor binding and social interaction in the rat.

Arginine vasopressin (AVP) is a peptide involved in social behaviors in rodents. To investigate the mechanism underlying the deficits in social behavior induced by blockade of N-methyl-D-aspartate (NMDA) receptors, this study examined the effect of noncompetitive NMDA antagonists on AVP receptor binding and social interaction in the rat. Subchronic phencyclidine (PCP) administration (2 mg/kg/day, 14 days, i.p.) significantly reduced the density of V1a receptor binding sites, labeled by an [125I]-Linear AVP antagonist, in several brain regions. Subchronic treatment with PCP or MK-801 (0.13 mg/kg/day, 14 days, i.p.) impaired social interactions in rats, as has been previously reported. These results suggest that NMDA antagonists have modulatory effects on the central vasopressinergic system and social interaction.

Animals↗
PubMed2003

Decreased volume and increased asymmetry of the anterior limb of the internal capsule in patients with schizophrenia.

BACKGROUND: The anterior limb of the internal capsule (ALIC) contains the anterior thalamic peduncle connecting the medial and anterior thalamic nuclei with the prefrontal cortex and the cingulate gyrus. The purpose of this study was to detect the volumetric changes in the ALIC in view of the putative abnormal frontothalamic connectivity in schizophrenia. METHODS: High-resolution, three-dimensional magnetic resonance imaging was acquired from 53 schizophrenia patients and 48 age- and gender-matched control subjects. Volumetric analysis was performed using consecutive 1-mm-thick coronal slices rostral to the anterior commissure, on the ALIC, caudate nucleus, and lentiform nucleus. White matter concentration over the whole brain was compared using the voxel-based morphometry (VBM) with Statistical Parametric Mapping 99. RESULTS: The patients had significantly decreased volumes in the bilateral ALIC and showed significantly increased right-greater-than-left asymmetry of the ALIC; VBM revealed a reduction in white matter concentration of the bilateral internal capsule in patients. No volumetric difference was found in the rostral part of the caudate and lentiform nucleus between groups. CONCLUSIONS: Decreased volume found in the ALIC supports the hypothesis of abnormal frontothalamic connectivity in schizophrenia. Increased asymmetry of the internal capsule seems consistent with the notion of predominantly left-side pathology of schizophrenia.

Adult↗
PubMed2003

Perigenual cingulate gyrus volume in patients with schizophrenia: a magnetic resonance imaging study.

BACKGROUND: Anterior cingulate gyrus abnormalities have been suggested to be involved in the pathophysiology of schizophrenia; however, little is known about morphologic changes in the perigenual cingulate gyrus in schizophrenia patients. METHODS: We investigated perigenual cingulate gyrus volume in 40 schizophrenia patients (20 men, 20 women) and 40 age- and gender-matched normal controls using magnetic resonance imaging. Volume of both gray and white matter of the perigenual cingulate gyrus was measured on consecutive axial 1-mm slices. RESULTS: Total (left and right) perigenual cingulate gray matter volume was significantly reduced in female schizophrenia patients compared with female controls. There was no significant difference in the gray matter volume of the perigenual cingulate gyrus between male patients and male controls. Left perigenual cingulate white matter volume was significantly reduced in the patient compared with the control group. Furthermore, significant gender differences were found in the total gray and white matter volume of the perigenual cingulate gyrus in control subjects (women > men), although these gender differences were not significant in the patient group. CONCLUSIONS: Our findings suggests volume reduction of the perigenual cingulate gyrus in schizophrenia patients, especially women and that gender differences in perigenual cingulate morphology among normal subjects are, as has been suggested for other parts of the brain, reduced in schizophrenia patients.

Adolescent↗
PubMed2003

Quantification of lateral ventricular subdivisions in schizophrenia by high-resolution three-dimensional magnetic resonance imaging.

In vivo brain imaging and postmortem investigations have demonstrated ventricular enlargement in the brains of schizophrenic patients. However, the extent of changes in the volume of discrete ventricle subdivisions has not been clearly established. We conducted high-resolution three-dimensional magnetic resonance imaging in 40 schizophrenic patients (20 males and 20 females) and 40 healthy volunteers (20 males and 20 females). The lateral ventricle in each hemisphere was divided into the anterior horn, body, posterior horn and temporal horn. The volumes of the hemispheres, four subdivisions of the lateral ventricles and the third ventricle were measured. Compared to the control subjects, the bilateral hemisphere volumes were significantly lower in the patients than in the control subjects. In the lateral ventricular subdivisions of the male patients, the most substantial volume increase was in the left temporal horn, and volume increases were also observed in the bilateral anterior horns and the right body. The male patients also had a significantly increased volume of the third ventricle. The female patients showed similar patterns with less statistical significance. Thus, the schizophrenia patients showed ventricular enlargement, particularly in the left temporal horn, being more severely affected in the male than in the female.

Adult↗