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Tsutomu Soma

Publications and source records attributed to Tsutomu Soma.

12 recordsLinked to original sources
PubMed2006

Regional cerebral blood flow changes in depression after electroconvulsive therapy.

A large number of studies have documented regional cerebral blood flow (rCBF) abnormalities in depression. A smaller yet significant number of studies have examined changes in rCBF before and after treatment. The findings, however, have been variable with regard to changes before and after electroconvulsive therapy (ECT). A consecutive series of patients (n=10) with drug-resistant major depressive episode according to DSM-IV with 17-item Hamilton Rating Scale for Depression (HRSD) scores greater than or equal to 14 gave their informed consent and were studied with technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (99mTc-ECD SPECT) before and after a course of ECT. The results were analyzed with statistical parametric mapping version 99. No region showed significant positive correlations between rCBF patterns of changes and HRSD changes, but three clusters emerged as showing significant negative correlations. These regions corresponded with left frontopolar gyrus, left amygdala, globus pallidus and nucleus accumbens, and left superior temporal gyrus. It was speculated that ECT affected both the prefrontal cortex, commonly assumed to be involved in depression, and the amygdala, known to play a central role in the processing of emotional stimuli, through the limbic-cortical-striatal-pallidal-thalamic circuit.

Adult↗
PubMed2006

Automatic volumetric measurement of segmented brain structures on magnetic resonance imaging.

PURPOSE: The purpose of this study was to produce a fully automatic volumetric segmented brain image system (AVSIS) and to evaluate its utility for measuring hippocampal volumes and total intracranial volume (TIV). MATERIALS AND METHODS: We developed a combination technique comprising an anatomical standardization technique to measure TIV, whole brain volume (WBV), and hippocampal volume obtained by magnetic resonance (MR) imaging. Altogether, 15 healthy volunteers and 15 patients with Alzheimer's disease (AD) underwent three-dimensional spoiled gradient echo (3D-SPGR) imaging. Three measurements were performed by manual volumetry as the gold standard, a previous semiautomatic method, and our new method, AVSIS. RESULTS: WBV and hippocampal volume in the AD group were significantly smaller than those in the healthy volunteer group measured by the semiautomatic method, manual method, and AVSIS. Each volume measured by AVSIS or semiautomatic method correlated with that measured by the manual method. The correlation coefficients between TIVs, WBVs, or hippocampal volumes measured by AVSIS and the manual method were 0.910, 0.902, and 0.918, respectively; the correlation coefficients between TIVs, or WBVs, measured by the previous semiautomatic method and the manual method were 0.875, and 0.886, respectively. CONCLUSION: We developed a system for a fully automatic measurement of segmented brain structures and obtained good results.

Age Factors↗
PubMed2005

Hair cycle-specific expression of versican in human hair follicles.

BACKGROUND: Versican, a large chondroitin sulfate proteoglycan molecule, is implicated in the induction of hair morphogenesis, the initiation of hair regeneration, and the maintenance of hair growth in mouse species. In contrast, in human hair follicles, the distribution and the roles of versican remains obscure. OBJECTIVES: To elucidate the implication of versican in normal human hair growth. METHODS: Versican expression was examined by in situ hybridization (mRNA) and immunohistochemistry (protein). RESULTS: The results clearly showed specific versican gene expression in the dermal papilla of anagen, which apparently decreased in the dermal papilla of catagen hair follicles. No specific signal was detectable in telogen hair follicles. Consistent with ISH results, versican immunoreactivity was extended over the dermal papilla of anagen hair follicles, and again, this staining diminished in the catagen phase of human hair follicles. Interestingly, versican proteins were deposited outside K15-positive epithelial cells in the bulge throughout the hair cycle. Versican immunoreactivity in the dermal papilla was almost lost in vellus-like hair follicles affected by male pattern baldness. CONCLUSION: Specific expression of versican in the anagen hair follicles suggests its importance to maintain the normal growing phase of human as well as mouse.

Adult↗
PubMed2004

Amyotrophic lateral sclerosis: diffusion tensor tractography and voxel-based analysis.

The purpose of this study is to investigate whether the diffusional anisotropy of water molecules is disrupted in the pyramidal and extra-pyramidal regions in patients with amyotrophic lateral sclerosis (ALS). We studied seven patients with probable ALS (four women, mean age +/- SD, 57.3 +/- 6.2 years old) according to the criteria of the World Federation of Neurology. A control group consisted of 11 age- and sex-matched volunteers (six women, 57.1 +/- 4.5) without disorders affecting the central nervous system. Voxel-based diffusion tensor analysis was made with statistical parametric mapping (SPM99). We also created the normalized corticospinal tractography from the diffusion tensor data. The significant fractional anisotropy (FA) decrease in the ALS group was found in the right frontal subgyral white matter and left frontal precentral white matter. These clusters with significant FA decrease corresponded well to the average group map of the corticospinal tract in a standard reference frame. These results suggested that the combination of voxel-based diffusion tensor analysis and diffusion tensor tractography might help determine the location of the affected neuronal tissues among ALS patients in a non-invasive manner.

Algorithms↗
PubMed2004

Accuracy and reproducibility of co-registration techniques based on mutual information and normalized mutual information for MRI and SPECT brain images.

We implemented a 3D co-registration technique based on mutual information (MI) including 2D image matching as a coarse pre-registration. The 2D coarse pre-registration was performed in the transverse, sagittal and coronal planes sequentially, and all six parameters were then optimized as fine registration. Normalized mutual information (NMI) was also examined as another entropy-based measure that was invariant to the overlapped area of two images. In order to compare accuracy and precision of the present method with a conventional two-level multiresolution approach, simulation was performed by 100 trials with the random initial mismatch of +/-10 degrees and +/-17.92 mm (Type-I) and +/-20 degrees and +/-40.32 mm (Type-II). For Type-I, no significant differences were found between registration errors of the multiresolution approach and the present method with the MI criterion. No biases were observed (< or =0.13 degrees and < or =0.57 mm for the multiresolution approach; < or =0.12 degrees and < or =0.57 mm for the present method) and the SDs were very small (< or =0.18 degrees and < or =0.12 mm for the multiresolution approach; < or =0.11 degrees and < or =0.11 mm for the present method). For Type-II, SDs for the multiresolution approach (< or =1.8 degrees and < or =0.88 mm) were markedly larger than those for the present method (< or =0.64 degrees and < or =0.20 mm) with MI. Success rate for the present method was 99.9%, which was higher than 97.6% for the multiresolution approach. Simulation also revealed that MI and NMI performance were almost equivalent. The choice of optimization strategy more affected accuracy and reproducibility than the choice of the registration criterion (MI or NMI) in our simulation condition. The present method is sufficiently accurate and reproducible for MRI-SPECT registration in clinical use.

Algorithms↗
PubMed2003

A potential suppressor of TGF-beta delays catagen progression in hair follicles.

TGF-beta plays important roles in the induction of catagen during the hair cycle. We examined whether TGF-beta2 could activate a caspase in human hair follicles. Using active caspase-9 and -3 specific antibodies, we found that TGF-beta2 activated these caspases in two regions, the lower part of the hair bulb and the outer layer of the outer root sheath. In addition, we searched for a plant extract that can effectively suppress TGF-beta action. We found that an extract of Hydrangea macrophylla reduced synthesis of a TGDbeta-inducible protein. We confirmed that the extract has a potential to promote hair elongation in the organ culture system. Furthermore, it delayed in vivo progression of catagen in a mouse model. Our results suggest that the induction of catagen by TGF-beta is mediated via activation of caspases and that a suppressor of TGF-beta could be effective in preventing male pattern baldness.

Animals↗
PubMed2003

Profile of transforming growth factor-beta responses during the murine hair cycle.

Transforming growth factor-beta (TGF-beta) appears to promote the regression phase of the mammalian hair cycle, in vivo in mice and in organ culture of human hair follicles. To assess the relationship between TGF-beta activity and apoptosis of epithelial cells during the murine hair cycle, we identified active TGF-beta responses using phospho-Smad2/3-specific antibodies (PS2). Strong, nuclear PS2 staining was observed in the outer root sheath throughout the anagen growth phase. Some bulb matrix cells were positive for PS2 during late anagen. Extensive, but weak, staining was observed in this region at the anagen-catagen transition. We also examined expression of TGF-beta-stimulated clone-22 (TSC-22), which is associated with TGF-beta-induced apoptosis of some cell lines. Recombinant rat TSC-22 was used to generate a rabbit anti-TSC-22 antibody useful for immunohistochemistry. TSC-22 RNA accumulation and immunoreactivity were observed in follicles throughout the murine hair cycle, including the dermal papilla and lower epithelial strand of late-catagen hair follicles. Neither the expression pattern nor the presence of nuclear TSC-22 correlated with the sites of apoptosis, suggesting that TSC-22 is not an effector of apoptosis in mouse catagen hair follicles. These studies support a complex role for TGF-beta in regulating the regression phase of the cycle, with potential for indirect promotion of apoptosis during the anagen-catagen transition.

Animals↗
PubMed2002

Cultured human dermal papilla cells secrete a chemotactic factor for melanocytes.

Large numbers of pigmented melanocytes are located in human hair follicles, predominantly around the dermal papillae, and the number of melanocytes and the melanogenic activity of the hair follicles are closely related to the hair cycle. We found that cultured human dermal papilla cells secreted a melanocyte chemoattractant into the medium. Skin fibroblasts also showed weak chemoattraction of melanocytes, while skin keratinocytes and melanocytes did not. Since this chemotactic activity was heat-and protease-sensitive and was present in the relatively high molecular weight fraction (130-200 kDa), it may be due to extracellular matrix (ECM) that proteins secreted from the cultured dermal papilla cells. This chemotactic signal between dermal papillae and melanocytes may control the localization and migration of hair melanocytes in vivo.

Cells, Cultured↗
PubMed2002

Involvement of transforming growth factor-beta2 in catagen induction during the human hair cycle.

The involvement of transforming growth factor-beta isoforms in the induction of the regressing phase (catagen) of human hair follicles were examined in vivo. In the growing phase (anagen), transforming growth factor-beta1 was detected at the hair cuticle and connective tissue sheath. Transforming growth factor-beta2 was restricted to the outermost cell layer of the outer root sheath. Transforming growth factor-beta3 was observed in the precortical hair matrix of anagen hair follicles. During the anagen-catagen transition phase, strong transforming growth factor-beta2 immunoreactivity appeared in the lower bulb matrix cells adjacent to the dermal papilla. In addition, transforming growth factor-beta2 and transforming growth factor-beta type II receptor were colocalized in the regressing epithelial strands, where terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling-positive apoptotic cells were also found. Transforming growth factor-beta1 and transforming growth factor-beta3 were mostly negative in the strand. Using an organ culture system, we investigated whether transforming growth factor-beta2 and its antagonists affected the transition process. Elongation of hair was significantly suppressed by transforming growth factor-beta2. Next, a neutralizing antibody and fetuin, a potent transforming growth factor-beta antagonist was tested. In the presence of the antibody as well as fetuin, hair follicles were markedly elongated in a concentration-dependent manner. These results strongly suggest that transforming growth factor-beta2 plays an essential part in the induction of the catagen phase of the human hair cycle.

Antibodies↗