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T Terashima

Publications and source records attributed to T Terashima.

At least 19 recordsLinked to original sources
PubMed2006

Vortex dynamics and the Fulde-Ferrell-Larkin-Ovchinnikov state in a magnetic-field-induced organic superconductor.

Under special conditions, a superconducting state where the order parameter oscillates in real space, the so-called FFLO state, is theoretically predicted to exist near the upper critical field, as first proposed by Fulde and Ferrell, and Larkin and Ovchinnikov. We report systematic measurements of the interlayer resistance in high magnetic fields to 45 T in the two-dimensional magnetic-field-induced organic superconductor lambda-(BETS)2FeCl4, where BETS is bis(ethylenedithio)tetraselenafulvalene. The resistance is found to show characteristic dip structures in the superconducting state. The results are consistent with pinning interactions between the vortices penetrating the insulating layers and the order parameter of the FFLO state. This gives strong evidence for an oscillating order parameter in real space.

Journal Article↗
PubMed2006

Glutamate reduces secretion of l-serine in astrocytes isolated from stroke-prone spontaneously hypertensive rats.

In the CNS, l-serine (l-Ser) plays an essential role in neuronal survival by evoking a variety of biological responses in glial cells. Initially, we examined whether glutamate, hydrogen peroxide (H(2)O(2)), interleukin-1 (IL-1) beta, and sodium nitroprusside (SNP) induce the secretion of l-Ser in astrocytes isolated from Wistar Kyoto rats (WKY). The secretion of l-Ser was significantly induced with glutamate and SNP in cultured astrocytes. Next, to gain insight into the involvement of l-Ser in glutamate-induced neuroprotection, we compared the secretion of l-Ser in astrocytes isolated from stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive rats, WKY. We also examined the mRNA expression of the enzyme that produces l-Ser, 3-phosphoglycerate dehydrogenase (PHGDH), and a neural amino acid transporter, ASCT1, in the cultured astrocytes. A dose-dependent study of glutamate in astrocytes of SHRSP indicated differences in the secretion of l-Ser, and gene expression of PHGDH and ASCT1, compared with levels in the WKY astrocytes. We demonstrated that both the secretion and the gene expression were significantly attenuated in glutamate-treated astrocytes from SHRSP. Cerebral ischemia in SHRSP induced a massive efflux of glutamate, causing delayed neuronal death in region CA1 of the hippocampus. The results suggest that the attenuated secretion of l-Ser in astrocytes is involved in neuronal vulnerability and survival in SHRSP during the production of glutamate, as the secretion of l-Ser, which is stimulated by glutamate, is closely related to the protective effect against glutamate-mediated neurotoxicity. We conclude that glutamate and SNP up-regulate the secretion of l-Ser in primary astrocytes. Secretion of l-Ser is regulated in astrocytes in response to glutamate and nitric oxide and may correspond to the level of l-Ser needed for neuronal survival during brain insults such as ischemic stroke in SHRSP.

Analysis of Variance↗
PubMed2005

Pressure-induced superconductivity in noncentrosymmetric heavy-fermion CeRhSi3.

We report the pressure-induced superconductivity in the noncentrosymmetric heavy-fermion CeRhSi3. The superconductivity emerges above about 12 kbar even though the antiferromagnetic ordering persists. Furthermore, another anomaly is observed in the superconducting phase. The anomalous magnetic field-temperature phase diagram with a high upper critical field suggests that an unconventional superconductivity is realized in CeRhSi3.

Journal Article↗
PubMed2004

Evolution of spin and field dependences of the effective mass with pressure in CeIn(3).

We have studied the field and spin dependences of the effective masses in CeIn3 as a function of pressure via the de Haas-van Alphen (dHvA) effect. The effective mass increases with the field at pressures up to about 10 kbar and then decreases with the field. The spin direction of the dominant dHvA oscillation is likely to be reversed across the same pressure. The dHvA frequency changes significantly at the pressure P(c) for the antiferromagnetic quantum critical point and two neighboring pressures P2 and P4 below and above P(c). The spin and field dependences rapidly diminish across P(c) and finally disappear above P4. These observations are discussed in conjunction with relevant observations and theories.

Journal Article↗
PubMed2004

de Haas-van Alphen effect in ZrZn2 under pressure: crossover between two magnetic states.

We report measurements of the de Haas-van Alphen effect in ZrZn2 under hydrostatic pressures up to 21 kbar where the Curie temperature vanishes. The exchange splitting of a Fermi surface changes in behavior with increasing magnetic field, which is qualitatively consistent with the behavior of the high-field magnetization, suggesting the existence of a crossover between two distinct magnetic states. These and previously unexplained findings may be understood in terms of a p-T-B phase diagram qualitatively similar to that of the ferromagnetic superconductor UGe2.

Journal Article↗
PubMed2004

Accelerated bone formation and increased osteoblast number contribute to the abnormal tooth germ development in parathyroid hormone-related protein knockout mice.

Our previous study showed that tooth germs at late embryonic stage [later than embryonic day 17.5 (E17.5)] and neonatal homozygous parathyroid hormone-related protein (PTHrP)-knockout mice are compressed or penetrated by the surrounding alveolar bone tissue. In vivo and in vitro studies have shown that the development of the tooth germ proper is not disturbed, but insufficient alveolar bone resorption, due to the decreased number and hypofunction of osteoclasts, is the main cause of this abnormality. In addition to the insufficient alveolar bone resorption, progressive bone formation toward tooth germs was observed in homozygous mice, suggesting that accelerated bone formation also contributes to this abnormality. To further investigate this, homozygous mice at E14.0 and E15.5, when alveolar bone is forming, were used for histochemical and bone histomorphometric analyses. In contrast to the late embryonic stage, the alveolar bone did not yet compress developing tooth germs in homozygous mice on E14.0, but a larger amount of bone tissue was seen compared to wild-type littermates. Histomorphometric analysis of bone at E14.0 revealed that the osteoblast numbers and surfaces in the mandibles and in the bone collar of femora of homozygous mice were significantly higher than those of wild-type mice. However, unlike our previous study showing the osteoclast surface on E18.5 in homozygous mice to be significantly lower than that of wild-type mice, this study at E14.0 showed no significant difference between the two genotypes. To evaluate the amount of calcification around tooth germs, 3D images of mandibles were reconstructed from the calcein-labeled sections of the wild-type and mutant mice. Labeling was performed at E14.0, and the mice were sacrificed 1 h after the calcein injection to minimize the effect of bone resorption. Comparison of the 3D images revealed that the labeled surface was larger around developing tooth germs in homozygous mouse than in wild-type mouse. On day E15.5, osteoblasts approached the enamel organ of homozygous mice but this was not observed in wild-type mice. In this study, we report a systemic increase in osteoblast number and accelerated bone formation in homozygous PTHrP-knockout mice, both of which contribute to the abnormal tooth development.

Acid Phosphatase↗
PubMed2003

Charge-ordered state in single-crystalline CaFeO3 thin film studied by x-ray anomalous diffraction.

X-ray anomalous diffraction, together with a band-structure calculation, was employed to obtain a quantitative understanding of the charge-ordering state in a single-crystalline CaFeO3 thin film. The experimental result shows a characteristic energy dispersion of the nearly inhibited reflection at 150 K, implying Fe atoms split into two distinct states. The energy dispersion is in good agreement with the calculated spectrum based on the LDA+U scheme. The calculation also reveals an electronic structure of the system where holes in the oxygen orbital surround one of the distinct Fe atoms, in spite of the total electron number in both Fe atoms remaining unchanged.

Journal Article↗
PubMed2003

Observation of band renormalization effects in hole-doped high-Tc Superconductors.

We report a systematic high-resolution angle-resolved photoemission spectroscopy on high-T(c) superconductors Bi(2)Sr(2)Ca(n-1)Cu(n)O(2n+4) (n=1-3) to study the origin of many-body interactions responsible for superconductivity. For n=2 and 3, a sudden change in the energy dispersion, so called "kink", becomes pronounced on approaching (pi,0) in the superconducting state, while a kink appears only around the nodal direction in the normal state. For n=1, the kink shows no significant temperature dependence even across T(c). This could suggest that the coupling of electrons with Q=(pi,pi) magnetic mode is dominant in the superconducting state for multilayered cuprates, while the interactions at the normal state and that of single-layered cuprates have a different origin.

Journal Article↗
PubMed2003

Protein oxidative damage in the stratum corneum: Evidence for a link between environmental oxidants and the changing prevalence and nature of atopic dermatitis in Japan.

BACKGROUND: The incidence of atopic dermatitis (AD) has increased in Japan, along with the number of patients with severe and treatment-resistant AD in urban and industrial areas. We hypothesize that these changes could be due to increased reactive oxygen species (ROS) generated from environmental pollution and solar radiation. OBJECTIVES: To demonstrate whether direct oxidative protein damage of the stratum corneum of the biopsied skin from AD patients is increased when compared with controls. PATIENTS AND METHODS: Carbonyl moieties in skin biopsies from 75 patients with AD were assessed using both spectrophotometric and immunohistochemical detection of the formation of dinitrophenylhydrazone (DNP) from dinitrophenylhydrazine (DNPH). These were compared with diseased and normal controls. Lipid peroxidation was also assessed by staining with antibody to 4-hydroxy-2-nonenal (4-HNE), an aldehyde product of oxidized omega-6-fatty acids. In addition, the activity of superoxide dismutase (SOD), an effective scavenger of ROS, was assessed and compared with controls. RESULTS: The level of protein carbonyl moieties in patients' skin was elevated and correlated directly with the severity of the disease. In contrast, DNP formation was not significantly increased in diseased controls, when compared with healthy volunteers, and no statistical significance was found between the two control groups. SOD activity was increased except for those with extra-severe disease. Positive staining with anti-DNP antibody and anti-4-HNE antibody were found in the most superficial layers of the stratum corneum. CONCLUSIONS: This study has found an association between AD severity and markers of ROS-associated damage, adding weight to the hypothesis that environmentally generated ROS may induce oxidative protein damage in the stratum corneum, leading to the disruption of barrier function and exacerbation of AD.

Adult↗
PubMed2003

Topical application of the immunosuppressant tacrolimus accelerates carcinogenesis in mouse skin.

BACKGROUND: Tacrolimus, produced by the fungus Streptomyces tsukabaensis, is a potent macrolide immunosuppressant widely used in liver and kidney transplantation. Topical tacrolimus has recently been found to be an effective treatment for atopic dermatitis (AD). OBJECTIVES: Because of the well-known association between T-cell immunosuppression and an increased risk of carcinogenesis, we investigated the effect of topical tacrolimus on skin carcinogenesis in 117 mice. METHODS: Approximately 8 cm2 of the shaved dorsal skin of 7-week-old female CD-1 mice was treated with 7,12-dimethylbenz[alpha]anthracene (DMBA) dissolved in acetone, which is in general use as a tumour initiator, or acetone alone, on day 1 of the experiment, followed by promoting treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without tacrolimus, or acetone with or without tacrolimus, for 20 weeks. The mice were divided into six treatment groups: (1) DMBA followed by acetone; (2) DMBA followed by TPA; (3) DMBA followed by acetone + tacrolimus; (4) DMBA followed by TPA + tacrolimus; (5) acetone followed by acetone + tacrolimus; and (6) acetone followed by acetone (control). RESULTS: The induction of skin tumours was significantly greater in the TPA-treated groups than in the absence of TPA. However, after 14 weeks there was marked synergy between tacrolimus and the DMBA/TPA regimen, with 0.47 +/- 0.13 (mean +/- SD) new tumours per mouse per week in group 4 vs. 0.10 +/- 0.025 in group 2 (P < 0.01), and 0.01 +/- 0.002 in group 3. A significant reduction in the CD4/CD8 ratio was found in axillary and inguinal lymph nodes in tacrolimus-treated mice, supporting the presumption that the immunosuppressive effect of the drug was responsible for its effect in promoting tumorigenesis. The major increase in tumours caused by topical tacrolimus was of papillomas, not squamous cell carcinomas. Papillomas are uncommon in humans, and are benign. However, 8.5% of the tumours found in the experiment were squamous cell carcinomas, and a considerable synergy between topical tacrolimus and conventional carcinogens was observed, raising the spectre of some risk of skin carcinogenesis in AD patients undergoing prolonged treatment with tacrolimus. CONCLUSIONS: Caution and careful surveillance are required with regard to skin lesions in patients treated with tacrolimus for prolonged periods.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Gene expression of growth differentiation factors in the developing periodontium of rat molars.

Growth and differentiation factors (GDF) 5, 6, and 7 are known to play roles in tendon and ligament formation, and are therefore probably involved in the formation of periodontal ligament. In this study, we sought to determine temporal and spatial expression of GDF-5, -6, and -7 mRNA in developing periodontal tissue of rat molars using in situ hybridization. GDF gene expression in the periodontal ligament was first detected in cells associated with the initial process of periodontal ligament fiber bundle formation. Gene signals were also detected in cells located along the alveolar bone and cementum surfaces, the insertion sites of periodontal ligaments, during the course of root formation. GDF expression in these cells were down-regulated after completion of root formation. Our results appeared to suggest the involvement of GDF-5, -6, and -7 in the formation of the dental attachment apparatus.

Alveolar Process↗
PubMed2002

Expression of Ca2+/calmodulin-dependent protein kinase (CaMK) Ibeta2 in developing rat CNS.

We observed the onset time and distribution pattern of beta2 isoform of Ca2+/calmodulin-dependent protein kinase I (CaMKIbeta2) in the CNS of the rat during the embryonic period until birth using an immunohistochemical method. The expression of CaMKIbeta2 started at embryological day 10 when the three primary brain vesicles and neural tube are generated from the neural plate. During the embryonic period, highly immunoreactive products were ubiquitously detected in neurons in the CNS, although neurons in the caudate-putamen and globus pallidus were faintly immunostained or immunonegative. High expression of CaMKIbeta2 persisted in the olfactory bulb, lymbic system, neocortex, septal nuclei, amygdala complex, some hypothalamic nuclei, pontine nuclei, Purkinje cells and granule cells in the cerebellar cortex through the developing period. At the subcellular level, CaMKIbeta2 was strongly expressed in nuclei of neurons but faintly in their cytoplasm, suggesting that this protein has an important role in the nuclear signaling pathway. This study demonstrates that expression of CaMKIbeta2 begins at the earliest developmental stage of the rat CNS and persists through the developing period.

Animals↗
PubMed2002

Abnormal distributions of callosal commissural and corticothalamic neurons in the cerebral neocortex of Shaking Rat Kawasaki.

Shaking Rat Kawasaki (SRK) is an autosomal recessive mutant rat recognized by unstable gait and tremor and by early death around the time of weaning. We previously reported that corticospinal tract neurons are malpositioned in the motor cortex of the SRK rat [Ikeda and Terashima (1997) J. Comp. Neurol. 383, 370-380]. In the present study, we examined the distribution pattern of callosal commissural (CC) and corticothalamic (CT) neurons of SRK and normal rats with the injection of horseradish peroxidase (HRP) into the contralateral hemisphere or wheat germ agglutinin-conjugated HRP into the ventral lateral thalamic nucleus. The intracortical distribution pattern of retrogradely labeled CC and CT neurons in the motor cortex of SRK rat was abnormal: CC neurons were more deeply situated and CT neurons were more superficially situated in the SRK cortex than the corresponding components in the normal cortex. Most of labeled CC and CT neurons had abnormal dendritic configurations. Statistical analysis revealed that the difference of the mean intracortical position of CC and CT neurons of the SRK was significantly different from the normal counterparts (Student's t-test, P<0.01). Taken together with previous findings, our data demonstrate that the abnormal cytoarchitecture of SRK cortex resembles the reeler cortex.

Agenesis of Corpus Callosum↗
PubMed2001

Branchiogenic motoneurons innervating facial, masticatory, and esophageal muscles show aberrant distribution in the reeler-phenotype mutant rat, Shaking Rat Kawasaki.

Shaking Rat Kawasaki (SRK) is an autosomal recessive mutant rat that is characterized by cerebellar ataxia. Although previous studies indicated many points of similarity between this mutant rat and the reeler mouse, nonlaminated structures such as the facial nucleus have not been studied in this mutant rat. Nissl-stained sections through the brainstem showed that the cytoarchitecture of the facial, motor trigeminal, and ambiguus nuclei was abnormal in SRK, especially in the lateral cell group of the facial nucleus and the compact formation of the ambiguus nucleus. To examine whether orofacial motoneurons are also malpositioned in the SRK rat, horseradish peroxidase (HRP) was injected into the facial, masticatory, and abdominal esophageal muscles of the SRK rats and normal controls to label facial, trigeminal, and ambiguus motoneurons, respectively. HRP-labeled facial, trigeminal, and ambiguus motoneurons of the SRK rat were distributed more widely than those of their normal counterparts, as in the case of the reeler mouse, with the one exception that labeled facial motoneurons innervating the nasolabial muscle were distributed more widely in the ventrolateral-to-dorsomedial direction in comparison with those of the reeler mutant. These data demonstrate that nonlaminated structures in the brainstem of the SRK rat are affected severely, as is the case in the reeler mutant mouse.

Animals↗
PubMed2001

Evolution of quasiparticle properties in UGe(2) with hydrostatic pressure studied via the de Haas-van Alphen effect.

We report measurements of the de Haas-van Alphen effect in UGe (2) under hydrostatic pressures up to 17.6 kbar, exceeding the critical pressure P(c) for the suppression of ferromagnetism. A discontinuous change of the Fermi surface is found to occur across P(c). Substantially enhanced effective masses (approximately 40m(e)) are found near P(c) on both the ferromagnetic and the paramagnetic sides.

Journal Article↗
PubMed2001

Cytokines involved in the systemic inflammatory response induced by exposure to particulate matter air pollutants (PM(10)).

Elevated levels of ambient particulate matter (PM(10)) have been associated with increased cardiopulmonary morbidity and mortality. We previously showed that the deposition of particles in the lung induces a systemic inflammatory response that includes stimulation of the bone marrow. This marrow response is related to mediators released by alveolar macrophages (AM) and in this study we measured cytokines produced by human AM exposed to ambient particles of different composition and size. Identified cytokines were also measured in the circulation of healthy young subjects exposed to air pollutants during the 1997 Southeast Asian forest fires. Human AM were incubated with particle suspensions of residual oil fly ash (ROFA), ambient urban particles (EHC 93), inert carbon particles, and latex particles of different sizes (0.1, 1, and 10 microm) and concentrations for 24 h. Tumor necrosis factor-alpha (TNF-alpha) increases in a dose-dependent manner when AM were exposed to EHC 93 particles (p < 0.02). The TNF response of AM exposed to different sizes of latex particles was similar. The latex (158 +/- 31%), inert carbon (179 +/- 32%), and ROFA (216 +/- 34%) particles all show a similar maximum TNF response (percent change from baseline) whereas EHC 93 (1,020 +/- 212%, p < 0.05) showed a greater maximum response that was similar to lipopolysaccharide (LPS) 1 microg/ml (812 +/- 320%). Macrophages incubated with an optimal dose of EHC 93 particles (0.1 mg/ml) also produce a broad spectrum of other proinflammatory cytokines, particularly interleukin (IL)-6 (p < 0.01), IL-1 beta (p < 0.05), macrophage inflammatory protein-1 alpha (MIP-1 alpha) (p < 0.05), and granulocyte macrophage colony-stimulating factor (GM-CSF) (p < 0.01) with no difference in concentrations of the anti-inflammatory cytokine IL-10 (p = NS). Circulating levels of IL-1 beta, IL-6, and GM-CSF were elevated in subjects exposed to high levels of PM(10) during an episode of acute air pollution. These results show that a range of different particles stimulate AM to produce proinflammatory cytokines and these cytokines are also present in the blood of subjects during an episode of acute atmospheric air pollution. We postulate that these cytokines induced a systemic response that has an important role in the pathogenesis of the cardiopulmonary adverse health effects associated with atmospheric pollution.

Aged↗
PubMed2001

Distribution of Ca(2+)/calmodulin-dependent protein kinase I beta 2 in the central nervous system of the rat.

Recently, we reported the mRNA localization of Ca(2+)/calmodulin-dependent protein kinase I beta 2 isoform (CaMKIbeta2) in the mouse nervous system. In the present study, polyclonal antibody against CaMKIbeta2 was generated and used to investigate the distribution of the enzyme within the central nervous system of the rat. Interestingly some differences were observed between the enzyme localization and previous mRNA detection [J. Neurochem. 268 (1999) 26512]. The strongest expression of the enzyme was found in pontine nuclei. Immunopositive fibers could be traced through the middle cerebellar peduncle until they reached the cerebellum. Quite strong staining could also be observed in almost all of the neurons in the neocortex, hippocampus, amygdala, hypothalamus, brainstem and cerebellum, including the nuclei of the cranial nerves and Purkinje cell layer of the cerebellar cortex which was not clearly detected in the previous in situ hybridization study. In the spinal cord, CaMKIbeta2 could be detected in the gray matter with stronger expression in the dorsal horn. CaMKIbeta2 showed very strong nuclear localization but was also present in the cytoplasm of some neurons. Such localization suggests that CaMKIbeta2 may be involved in many neuronal functions in the central nervous system, including the possibility of important roles in nuclear signal transduction.

Animals↗