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Yutaka Masuda

Publications and source records attributed to Yutaka Masuda.

At least 19 recordsLinked to original sources
PubMed2006

A novel 21-kDa cytochrome c-releasing factor is generated upon treatment of human leukemia U937 cells with geranylgeraniol.

Geranylgeraniol (GGO) induces apoptosis in various lines of human tumor cells through a mitochondrion-dependent pathway. The present study describes identification of a 21-kDa cytochrome c-releasing factor that appears in the cytosolic fraction after treatment of human leukemia U937 cells with GGO. Incubation of isolated mitochondria with a lysate of U937 cells that had been treated with GGO resulted in the release of cytochrome c from the mitochondria. Utilizing this cell-free system, we purified a 21-kDa protein that induced the release of cytochrome c from mitochondria and appeared to be involved in the apoptosis that is induced in U937 cells by GGO. We designated this protein cytochrome c-releasing factor 21 (CRF21). Overexpression of CRF21 in HeLa cells induced the release of cytochrome c from mitochondria, with subsequent apoptosis. Our results suggest that CRF21 might play an important role in the induction of apoptosis by GGO in leukemia U937 cells.

Amino Acid Sequence↗
PubMed2006

A psychological study on patients with masticatory muscle disorder and sleep bruxism.

Sleep bruxism (SB) has been believed to be related to stress and psychosocial factors, however their implicit relationship has remained unclear. This study was conducted on patients visiting our clinic with SB and masticatory muscle disorders (MMD) for the purpose of clarifying personality and behavioral traits. This study was conducted on patients of MMD visiting our clinic. The Rosenzweig Picture-Frustration study was performed on each patient. Twenty-seven (27) patients were divided into two groups: 17 patients with SB and 10 patients without. The SB group showed a significantly lower level of E (extrapunitive) reaction than the nonSB group. SB patients showed a significantly higher level of M (impunitive) reaction than those without SB. Concerning the directions of aggression, the percentage of E-A (extraaggression) was significantly lower in SB patients than in those without. On the other hand, the percentage of I-A (intraaggression) was significantly higher in patients with SB than those without. Our study found a new aspect of the patients with MMD and SB: they are not only intraaggressive, but are also unable to be extrapunitive and extraaggressive. Consequently, they are unable to demonstrate adequate self-assertiveness in stressful situations.

Adolescent↗
PubMed2005

ADRP/adipophilin is degraded through the proteasome-dependent pathway during regression of lipid-storing cells.

Adipose differentiation-related protein (ADRP) is a major protein associated with lipid droplets in various types of cells, including macrophage-derived foam cells and liver cells. However, the role of ADRP in the processes of formation and regression of these cells is not understood. When J774 murine macrophages were incubated with either VLDL or oleic acid, their content of both ADRP and triacylglycerol (TG) increased 3- to 4-fold. Induction of ADRP during TG accumulation was also observed in oleic acid-treated HuH-7 human liver cells. Addition of triacsin C, a potent inhibitor of acyl-CoA synthase, for 6 h decreased the amount of TG in VLDL-induced foam cells and oleic acid-treated liver cells; it decreased the amount of ADRP protein in parallel, indicating the amount of ADRP reduced during regression of the lipid-storing cells. Addition of a proteasome inhibitor during triacsin C treatment abolished the ADRP decrease and accumulated polyubiquitinated ADRP. In addition, the proteasome inhibitor reversed not only the degradation of ADRP but also TG reduction by triacsin C. These results suggest that cellular amounts of ADRP and TG regulate each other and that the ubiquitin-proteasome system is involved in degradation of ADRP during regression of lipid-storing cells.

Amino Acid Sequence↗
PubMed2005

From stem cells to viable autologous semilunar heart valve.

BACKGROUND: An estimated 275,000 patients undergo heart valve replacement each year. However, existing solutions for valve replacement are complicated by the morbidity associated with lifelong anticoagulation of mechanical valves and the limited durability of bioprostheses. Recent advances in tissue engineering and our understanding of stem cell biology may provide a lifelong solution to these problems. METHODS AND RESULTS: Mesenchymal stem cells were isolated from ovine bone marrow and characterized by their morphology and antigen expression through immunocytochemistry, flow cytometry, and capacity to differentiate into multiple cell lineages. A biodegradable scaffold was developed and characterized by its tensile strength and stiffness as a function of time in cell-conditioned medium. Autologous semilunar heart valves were then created in vitro using mesenchymal stem cells and the biodegradable scaffold and were implanted into the pulmonary position of sheep on cardiopulmonary bypass. The valves were evaluated by echocardiography at implantation and after 4 months in vivo. Valves were explanted at 4 and 8 months and examined by histology and immunohistochemistry. Valves displayed a maximum instantaneous gradient of 17.2+/-1.33 mm Hg, a mean gradient of 9.7+/-1.3 mm Hg, an effective orifice area of 1.35+/-0.17 cm2, and trivial or mild regurgitation at implantation. Gradients changed little over 4 months of follow-up. Histology showed disposition of extracellular matrix and distribution of cell phenotypes in the engineered valves reminiscent of that in native pulmonary valves. CONCLUSIONS: Stem-cell tissue-engineered heart valves can be created from mesenchymal stem cells in combination with a biodegradable scaffold and function satisfactorily in vivo for periods of >4 months. Furthermore, such valves undergo extensive remodeling in vivo to resemble native heart valves.

Animals↗
PubMed2005

Repeated immunization induces the increase in fucose content on antigen-specific IgG N-linked oligosaccharides.

OBJECTIVE: In order to investigate whether repeated immunization induces changes in IgG glycosylation, we analyzed the composition of oligosaccharides on antigen-specific IgGs obtained from mice that received different amounts of immunization boosts. METHODS: Three groups of mice were immunized with ovalbumin (OVA) and boosted once, twice, or three times, respectively, with an interval of 1 week. The patterns of oligosaccharides present in anti-OVA specific IgGs were analyzed using lectin-enzyme-linked immunosorbent assay (ELISA) and lectin-blot. RESULTS: The repeated injection of OVA induced both the production of specific IgGs and an increase of fucose content in N-linked oligosaccharides of the IgGs. The lowest IgG fucosylation was observed in mice boosted once, whereas the highest fucosylation rate was observed in mice boosted three times. ELISA assay demonstrated that there was a positive relationship between the fucose content and amount of immunization boosts. CONCLUSIONS: IgG fucosylation increases during repeated immunization with ovalbumin. The alteration of IgG fucosylation may have important biological significance.

Animals↗
PubMed2005

[Management and treatment of headache in the pain clinic].

Nerve block therapy is one of the non-pharmacological methods in headache treatment. Most pain clinics in Japan use nerve block therapy to treat pain together with pharmacological methods. Sensory nerve blocks such as the trigger point block, occipital nerve block, trigeminal nerve block, C-2, 3 spinal nerve block, etc., are effective for headache pain. One of the characteristic treatments of headache in the pain clinic in Japan is the stellate ganglion block(SGB). Although it has not been fully clarified why SGB is effective in treating headache, stabilization of the abnormal sympathetic nerve function, suppression of inflammation of vascular wall etc., are thought to be related to the effectiveness of SGB. Nerve block therapy is effective for the treatment of headache patients and offers us an important therapeutic option for treatment of headache pain.

Headache↗
PubMed2004

Recombinant curculin heterodimer exhibits taste-modifying and sweet-tasting activities.

Curculin from Curculigo latifolia is a unique sweet protein that exhibits both sweet-tasting and taste-modifying activities. We isolated a gene that encodes a novel protein highly homologous to curculin. Using cDNAs of the previously known curculin (designated as curculin1) and the novel curculin isoform (curculin2), we produced a panel of homodimeric and heterodimeric recombinant curculins by Escherichia coli expression systems. It was revealed that sweet-tasting and taste-modifying activities were exhibited solely by the heterodimer of curculin1 and curculin2.

Amino Acid Sequence↗
PubMed2004

Involvement of tumor necrosis factor receptor-associated protein 1 (TRAP1) in apoptosis induced by beta-hydroxyisovalerylshikonin.

beta-Hydroxyisovalerylshikonin (beta-HIVS), a compound isolated from the traditional oriental medicinal herb Lithospermum radix, is an ATP non-competitive inhibitor of protein-tyrosine kinases, such as v-Src and EGFR, and it induces apoptosis in various lines of human tumor cells. However, the way in which beta-HIVS induces apoptosis remains to be clarified. In this study, we performed cDNA array analysis and found that beta-HIVS suppressed the expression of the gene for tumor necrosis factor receptor-associated protein 1 (TRAP1), which is a member of the heat-shock family of proteins. When human leukemia HL60 cells and human lung cancer DMS114 cells were treated with beta-HIVS, the amount of TRAP1 in mitochondria decreased in a time-dependent manner during apoptosis. A similar reduction in the level of TRAP1 was also observed upon exposure of cells to VP16. Treatment of DMS114 cells with TRAP1-specific siRNA sensitized the cells to beta-HIVS-induced apoptosis. Moreover, the reduction in the level of expression of TRAP1 by TRAP1-specific siRNA enhanced the release of cytochrome c from mitochondria when DMS114 cells were treated with either beta-HIVS or VP16. The suppression of the level of TRAP1 by either beta-HIVS or VP16 was blocked by N-acetyl-cysteine, indicating the involvement of reactive oxygen species (ROS) in the regulation of the expression of TRAP1. These results suggest that suppression of the expression of TRAP1 in mitochondria might play an important role in the induction of apoptosis caused via formation of ROS.

Acetylcysteine↗
PubMed2004

The AHNAKs are a class of giant propeller-like proteins that associate with calcium channel proteins of cardiomyocytes and other cells.

To explore the function of the giant AHNAK molecule, first described in 1992 [Shtivelman, E., Cohen, F. E. & Bishop, J. M. (1992) Proc. Natl. Acad. Sci. USA 89, 5472-5476], we created AHNAK null mice by homologous recombination. Homozygous knockouts showed no obvious phenotype, but revealed instead a second AHNAK-like molecule, provisionally designated AHNAK2. Like the original AHNAK, AHNAK2 is a 600-kDa protein composed of a large number of highly conserved repeat segments. Structural predictions suggest that the repeat segments of both AHNAKs may have as their basic framework a series of linked, antiparallel beta-strands similar to those found in beta-propeller proteins. Both AHNAKs appear to localize to Z-band regions of mouse cardiomyocytes and cosediment with membrane vesicles containing the dihydropyridine receptor, which is consistent with earlier reports that the AHNAKs are linked to L-type calcium channels and can be phosphorylated by protein kinase A. The localization of the AHNAKs in close proximity to transverse tubule membranes and Z-band regions of cardiac sarcomeres raise the possibility that they might be involved in regulating excitation/contraction coupling of cardiomyocytes, but other studies indicate that the association of AHNAKs with calcium channel proteins is more widespread. AHNAK2 is predicted to have a PDZ domain within its N-terminal, nonrepeating domain, which may mediate these interactions.

Amino Acid Sequence↗
PubMed2004

Tissue-engineered microvessels on three-dimensional biodegradable scaffolds using human endothelial progenitor cells.

Tissue engineering may offer patients new options when replacement or repair of an organ is needed. However, most tissues will require a microvascular network to supply oxygen and nutrients. One strategy for creating a microvascular network would be promotion of vasculogenesis in situ by seeding vascular progenitor cells within the biopolymeric construct. To pursue this strategy, we isolated CD34(+)/CD133(+) endothelial progenitor cells (EPC) from human umbilical cord blood and expanded the cells ex vivo as EPC-derived endothelial cells (EC). The EPC lost expression of the stem cell marker CD133 but continued to express the endothelial markers KDR/VEGF-R2, VE-cadherin, CD31, von Willebrand factor, and E-selectin. The cells were also shown to mediate calcium-dependent adhesion of HL-60 cells, a human promyelocytic leukemia cell line, providing evidence for a proinflammatory endothelial phenotype. The EPC-derived EC maintained this endothelial phenotype when expanded in roller bottles and subsequently seeded on polyglycolic acid-poly-l-lactic acid (PGA-PLLA) scaffolds, but microvessel formation was not observed. In contrast, EPC-derived EC seeded with human smooth muscle cells formed capillary-like structures throughout the scaffold (76.5 +/- 35 microvessels/mm(2)). These results indicate that 1) EPC-derived EC can be expanded in vitro and seeded on biodegradable scaffolds with preservation of endothelial phenotype and 2) EPC-derived EC seeded with human smooth muscle cells form microvessels on porous PGA-PLLA scaffolds. These properties indicate that EPC may be well suited for creating microvascular networks within tissue-engineered constructs.

AC133 Antigen↗
PubMed2004

Slip-down from a raised platform: another behavior of Slc:ddY mice treated with methamphetamine.

Slip-down behavior from a raised platform of Slc:ddY mice was examined. Mice intraperioneally injected with 1 or 1.5 mg/kg of methamphetamine (MAP) slipped down from a raised platform of 10 cm diameter and 20 cm height within 5 min, 20 min after the injection. After pretreatment five times with 1 mg/kg MAP at intervals of 3 days, the slip-down was induced after injection of 0.5, 1 or 1.5 mg/kg MAP, but after pretreatment ten times with 1 mg/kg MAP at intervals of 3 days the behavior was not recognized at the same doses. These phenomena were like reverse-tolerance and tolerance. The situational change of the MAP treatments, placement on the platform after each pretreatment, did not affect the phenomena. The present findings strongly suggest that the slip-down is a behavior affected by the dose and number of administration of MAP, but not by the treatment situation.

Animals↗
PubMed2003

Beta-hydroxyisovalerylshikonin induces apoptosis in human leukemia cells by inhibiting the activity of a polo-like kinase 1 (PLK1).

beta-Hydroxyisovalerylshikonin (beta-HIVS), which was isolated from the plant, Lithospermum radix, induces apoptosis in various lines of human tumor cells. To identify genes involved in beta-HIVS-induced apoptotic process, we performed cDNA array analysis and found that beta-HIVS suppresses the expression of the gene for a polo-like kinase 1 (PLK1) that is involved in control of the cell cycle. When U937 and HL60 cells were treated with 10(-6) M beta-HIVS for 0.5 h, both the amount of PLK1 itself and the kinase activity of this enzyme were decreased. By contrast, Bcr-Abl-positive K562 cells were resistant to the induction of apoptosis by beta-HIVS and this compound did not suppress the kinase activity of PLK1 in these cells. However, simultaneous treatment of K562 cells with both beta-HIVS and STI571, which selectively inhibits the protein tyrosine kinase (PTK) activity of Bcr-Abl, strongly induced apoptosis. Moreover, beta-HIVS increased the inhibitory effect of STI571 on PTK activity. Treatment of K562 cells with antisense oligodeoxynucleotides (ODNs) specific for PLK1 sensitized these cells to the beta-HIVS-induced fragmentation of DNA. These results suggest that suppression of the activity of PLK1 via inhibition of tyrosine kinase activity by beta-HIVS might play a critical role in the induction of apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Suitable shunt size for regulation of pulmonary blood flow in a canine model of univentricular parallel circulations.

OBJECTIVE: We examined the influence of shunt size on regulation of the pulmonary blood flow in a canine model of a univentricular heart because specific guidelines regarding suitable shunt size in the Norwood operation remain undetermined. METHODS: Beagle dogs (n = 8) 3 to 7 months old and weighing 3.0 to 5.0 kg were used. Atrial septectomy and patch closure of the tricuspid valve were performed, and a systemic-pulmonary arterial shunt was created by interposing a 3.5- or 4.0-mm graft between the right subclavian artery and main pulmonary artery. After cardiopulmonary bypass, hemodynamic variables including pulmonary and systemic blood flow were measured consecutively according to physiologically respiratory manipulations. The ratio of shunt size to body weight ranged from 0.80 to 1.33 mm/kg (1.08 +/- 0.16 mm/kg). RESULTS: Each dog with a ratio of shunt size to body weight of 0.8 to 1.1 showed significant negative correlation between the pulmonary/systemic blood flow ratio and arterial Pco(2), but those with a ratio of shunt size to body weight of 1.1 to 1.4 did not. Consequently each dog with a ratio of shunt size to body weight of 0.8 to 1.0 got adequate systemic flow, whereas a ratio of 1.0 to 1.4 resulted in inadequate systemic flow and acidic status. Similar phenomena were shown with the grouped data on relationship between the pulmonary/systemic blood flow ratio and inspired oxygen fraction. CONCLUSIONS: These findings imply that when the ratio of shunt size to body weight is 0.8 to 1.1, the pulmonary/systemic blood flow ratio is controllable by physiologic respiratory manipulations. Larger shunts make pulmonary blood flow excessive and uncontrollable. We recommend that a ratio of shunt size to body weight of 0.9 to 1.0 be considered a useful index for suitable systemic-pulmonary arterial shunt in the Norwood operation.

Animals↗
PubMed2003

Pharmacological mechanism in slip-down behavior of mice.

Slip-down from a raised platform was previously found in mice treated with morphine, and this behavior was also recognized in mice treated with a monoamine releaser methamphetamine. Pharmacological examination on the slip-down indicated that the behavior was induced by receptor stimulations by D2 agonist PPHT and 5HT-2 agonist DOI. In mice treated with PPHT, antagonists of D1, alpha2, 5HT-2 and opioid mu and kappa suppressed the behavior. In mice treated with DOI, antagonists of D1, alpha2, 5HT-1A, 5HT-3 and opioid mu and delta suppressed the behavior. These present findings suggest that the slip-down was mainly induced by opioid mu receptor activity regulated with monoamine activities. When the slip-down is considered as an anxious behavior, it may be also suggested that the anxiety induced by 5-HT activities furthermore stimulated the behavior via the other opioid receptor activities.

Animals↗
PubMed2003

Determination of plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and patients with atherosclerosis.

We previously found that human chymase cleaves big endothelins at the Tyr31-Gly32 bond and produces 31-amino-acid endothelins, endothelins(1-31). Endothelin-1(1-31) has been isolated from a number of human organs, including the heart and lungs. As endothelin-1 has been shown to play a significant role in the paracrine regulation of cardiovascular functions in humans, it is possible that endothelin-1(1-31) may also exhibit biological activity on human tissues. We previously reported that synthetic endothelin-1(1-31) exhibits a number of physiological actions on cultured cells in vitro. In the present study, we investigated the plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and compared them with those in patients with cardiovascular diseases. Endothelin-1(1-31) and endothelin-1 in human plasma was measured using a sandwich-enzyme-immunoassay system, which was recently described for measurement of endothelin-1(1-31). The plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy volunteers were 19.24 +/- 5.70 and 15.54 +/- 4.45 pg/ml (n = 5), respectively. We also measured plasma concentrations of endothelin-1(1-31) and endothelin-1 before and after surgery in patients with abdominal aortic aneurysms. Before surgery, plasma concentrations of endothelin-1(1-31) and endothelin-1 in these patients were higher than those in healthy individuals. After surgery, both endothelin-1(1-31) and endothelin-1 in plasma decreased to levels similar to those of healthy subjects. This suggests that endothelin-1(1-31) may have similar physiological significance to endothelin-1 in patients with atherosclerosis.

Adult↗
PubMed2002

Sophoranone, extracted from a traditional Chinese medicine Shan Dou Gen, induces apoptosis in human leukemia U937 cells via formation of reactive oxygen species and opening of mitochondrial permeability transition pores.

Screening of various natural products in a search for novel inducers of apoptosis in human leukemia cells led us to identify the strong apoptosis-inducing activity in a fraction extracted with methanol from the roots of Sophora subprostrata Chun et T. Chen. We purified the compound that induced apoptosis in human leukemia cells and identified it as sophoranone. Sophoranone inhibited cell growth and induced apoptosis in various lines of cells from human solid tumors, with 50% inhibition of growth of human stomach cancer MKN7 cells at 1.2 +/- 0.3 microM. The growth-inhibitory and apoptosis-inducing activities of sophoranone for leukemia U937 cells were very much stronger than those of other flavonoids, such as daidzein, genistein and quercetin. At the early stages of treatment of U937 cells with sophoranone, reactive oxygen species were formed, mitochondrial permeability pores were opened and cytochrome c was released from mitochondria. Cytochrome c was also released upon treatment of isolated mitochondria with sophoranone. Inhibitors of complexes III and IV, but not complexes I and II, of the mitochondrial respiratory chain prevented the release of cytochrome c from isolated mitochondria by sophoranone, as well as the induction of apoptosis in U937 cells in response to sophoranone. Our results indicate that sophoranone might be a unique apoptosis-inducing anticancer agent that targets mitochondria.

Apoptosis↗
PubMed2002

Effect of serotonin 1A agonist tandospirone on depression symptoms in senile patients with dementia.

The treatment of depression in senile patients with dementia is difficult with the drugs used formerly. The effects of a new anxiolytic drug, tandospirone, were investigated on depression symptoms in nine senile patients with dementia using Hamilton Depression Rating Scale (HAM-D) items. Tandospirone improved the symptoms, especially the depressive mood, agitation and anxiety, although a slight gastrointestinal symptom was found in one patient. The findings in the present study may suggest that tandospirone is a useful and comparatively safe drug for depression symptoms in senile patients with dementia.

Aged↗