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Tsuchiya M, Yoshida T, Taniguchi S, Yasuda K, Maeda A, Hayashi A, Tanaka J, Shigemoto M, Nitta K, Tsuchiya K. In vivo suppression of mafA mRNA with siRNA and analysis of the resulting alteration of the gene expression profile in mouse pancreas by the microarray method. Biochem Biophys Res Commun 2007; 356:129-35. [PMID: 17346669 DOI: 10.1016/j.bbrc.2007.02.105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/20/2007] [Indexed: 10/23/2022]
Abstract
Maf is a family of transcription factor proteins that is characterized by a typical bZip structure, and one of the large mafs, mafA is a strong transactivator of insulin. To explore the role of mafA in the pancreas, we modified the mafA mRNA level in vivo in mice by the RNA interference (siRNA) technique and analyzed the resulting alteration of the expressed gene profile with a microarray system. The mafA expression level in siRNA-treated mice was reduced approximately 60% compared with control-siRNA-treated animals. Microarray analysis revealed changes in the expression level of several genes in the siRNA-treated mice, with prominent down-regulated expression of the genes encoding insulin, glucagon, and adipocytokines, suggesting possible role of mafA in the pathophysiological states of impaired metabolic responses or inflammatory reactions.
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Suzuki S, Sato T, Maeda A, Takahashi Y. 99 Program design based on a mathematical model using rating of perceived exertion for an elite sprinter: a case study. J Sci Med Sport 2005. [DOI: 10.1016/s1440-2440(17)30594-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Shima N, Maeda A, Hirohashi K. Delayed Latency of Peroneal Reflex to Sudden Inversion with Ankle Taping or Bracing. Int J Sports Med 2005; 26:476-80. [PMID: 16037891 DOI: 10.1055/s-2004-821064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The purpose of the present study was to examine the effects of ankle taping and bracing based on the peroneal reflex in the hypermobile and normal ankle joints with and without history of ankle injury. Thirty-six ankle joints of 18 collegiate American football athletes with and without previous history of injury were studied. The angle of talar tilt (TT) was measured by stress radiograph for classifying normal (TT</=5 degrees ) or hypermobile (TT>5 degrees ) ankles. They were tested with taping, bracing, and without any supports as a control. The latency of peroneus longus muscle was measured by a sudden inversion of 25 degrees using surface EMG signals. The results of the present study show no significant three-way Group (hypermobile or normal ankles) by History (previously injured or uninjured ankles) by Condition (control, taping, or bracing) interaction, while Condition main effect was significant (p<0.05). There were significant differences between control (80.8 ms) and taping (83.8 ms, p<0.01), between control and bracing (83.0 ms, p<0.05), but not between taping and bracing (p>0.05). In conclusion, ankle taping and bracing delayed the peroneal reflex latency not only for hypermobile ankles and/or injured ankle joints but also for intact ankle joints.
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Maeda A, Inoue Y, Kitano H, Savel'ev S, Okayasu S, Tsukada I, Nori F. Nanoscale friction: kinetic friction of magnetic flux quanta and charge density waves. PHYSICAL REVIEW LETTERS 2005; 94:077001. [PMID: 15783842 DOI: 10.1103/physrevlett.94.077001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Indexed: 05/24/2023]
Abstract
In analogy with the standard macroscopic friction, here we present a comparative study of the friction force felt by moving vortices in superconductors and charge density waves. Using experiments and a model for this data, our observations (1) provide a link between friction at the micro- and macroscopic scales, (2) explain the roundness of the static-kinetic friction transition in terms of thermal fluctuations, particle interactions, and system size (critical-phenomena view), and (3) explain the crossing of the kinetic friction F(k) versus velocity V for our pristine (high density of very weak defects) and our irradiated samples (with lower density of deeper pinning defects).
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Maeda A, Matsumoto S, Kishida H, Takenobu T, Iwasa Y, Shiraishi M, Ata M, Okamoto H. Large optical nonlinearity of semiconducting single-walled carbon nanotubes under resonant excitations. PHYSICAL REVIEW LETTERS 2005; 94:047404. [PMID: 15783596 DOI: 10.1103/physrevlett.94.047404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2004] [Indexed: 05/24/2023]
Abstract
We measured third-order nonlinear susceptibility (chi(3)) spectra in semiconducting single-walled carbon nanotubes (SWNTs) by the Z-scan method. |Imchi(3)| is remarkably enhanced under resonant excitation to the lowest interband transition, reaching 4.2 x 10(-6) esu and 1.5 x 10(-7) esu in SWNTs grown by the laser ablation and HiPco methods, respectively. A comparison of the transient absorption changes evaluated by degenerate and nondegenerate pump-probe measurements suggests that the resonant enhancement of |Imchi(3)| is dominated by a coherent process rather than by saturation of absorption.
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Morisawa Y, Maeda A, Sato T, Hisakawa H, Fujieda M, Wakiguchi H. Primary cytomegalovirus infection as a common cause of wheezing in infants. J Allergy Clin Immunol 2005. [DOI: 10.1016/j.jaci.2004.12.711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Takagi Y, Higashi N, Kawai S, Maeda A, Ueba N. Effects of traditional oriental medicine on influenza virus infection:. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.02.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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58
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Takagi Y, Higashi N, Kawai S, Maeda A, Ueba N. Effects of traditional oriental medicine on influenza virus infection: Enhancing effect of traditional oriental medicines on antibody production to B strain after vaccination with influenza HA vaccine in aged mice. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.01.092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Goto M, Johansson H, Maeda A, Elgue G, Korsgren O, Nilsson B. Low–molecular weight dextran sulfate abrogates the instant blood-mediated inflammatory reaction induced by adult porcine islets both in vitro and in vivo. Transplant Proc 2004; 36:1186-7. [PMID: 15194411 DOI: 10.1016/j.transproceed.2004.04.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND One of the main obstacles to clinical application of islet xenotransplantation is the injurious inflammatory reaction elicited by porcine islets when they are exposed to fresh human blood in vitro and in vivo. This instant blood-mediated inflammatory reaction (IBMIR) causes rapid binding of platelets to the islet surface, activation of the coagulation and complement systems, and leukocyte infiltration of the islets. As a consequence of IBMIR, morphological destruction of porcine islets occurs within the first few hours after transplantation. MATERIALS AND METHODS In the present study, by analyzing the plasma samples and performing immunohistochemical investigation, we assessed the effect of adding low-molecular weight dextran sulfate (LMW-DS) at 0.01-1 mg/mL to an in vitro tubing loop assay in which porcine islets were exposed to fresh human blood. The effect of LMW-DS also was investigated in an in vivo model using diabetic athymic mice, which provides an innate inflammatory milieu without influence of T cells. The possible toxicity of LMW-DS was assessed by culturing pig islets in the presence or absence of LMW-DS for 3 days. RESULTS In the in vitro study, in the presence of LMW-DS at 0.01 mg/mL, platelet consumption, coagulation, and complement activation were reduced, and, at 0.1 mg/mL, LMW-DS totally prevented IBMIR. Immunohistochemical investigation showed that leukocyte infiltration was totally abrogated at the highest dose. A similar finding was observed in the in vivo study. No adverse effect of LMW-DS was observed on the quality of the islets. CONCLUSIONS LMW-DS appears to be an effective drug candidate that is able to control the strong innate immune response induced by pig islets in contact with human blood.
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Niikura M, Maeda A, Ikegami T, Saijo M, Kurane I, Morikawa S. Modification of endothelial cell functions by Hantaan virus infection: prolonged hyper-permeability induced by TNF-alpha of hantaan virus-infected endothelial cell monolayers. Arch Virol 2004; 149:1279-92. [PMID: 15221531 DOI: 10.1007/s00705-004-0306-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Accepted: 01/28/2004] [Indexed: 10/26/2022]
Abstract
Serious vascular leakage is central to the pathogenesis of hantavirus infections. However, there is no evidence suggesting the hantavirus infection of endothelial cells directly causes obvious cell damage or morphological alteration either in vivo or in vitro. In this study, we examined whether Hantaan virus (HTNV) infection modifies the barrier function of endothelial cell monolayers upon the exposure to pro-inflammatory cytokines. Low levels (1 ng/ml) of tumor necrosis factor-alpha initially increased the permeability in both HTNV-infected and uninfected monolayers similarly. Thereafter, however, these monolayers showed significant difference. The HTNV-infected monolayers remained irreversibly hyper-permeable during the experimental period up to 4 days, while the uninfected monolayers completely recovered the barrier function. The prolonged hyper-permeability of HTNV-infected monolayers was not associated with cell death or gap formation in the monolayers, and was independent from their nitric oxide or prostaglandin production. These results are the first evidence that hantavirus infection modifies barrier function of endothelial cell monolayers and suggest that HTNV-infection of endothelial cells may contribute to the increased vascular leakage through the prolonged response to cytokines.
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Inoue N, Manabe N, Nakayama M, Matsui T, Maeda A, Nakagawa S, Miyamoto H. 222THE ROLE OF TUMOR NECROSIS FACTOR-RELATED APOPTOSIS INDUCING LIGAND
DURING FOLLICULAR ATRESIA IN PIG OVARIES. Reprod Fertil Dev 2004. [DOI: 10.1071/rdv16n1ab222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce cell death by binding to its receptors (DR4 and DR5). However, binding to DcR1 or DcR2 cannot induce apoptosis. DcRs compete with DRs. TRAIL has been reported to induce apoptosis in various tumor cells but not in normal cells. However, a recent study revealed that TRAIL induces apoptosis in normal hepatocytes of human but not in those of rat, mouse, or rhesus monkey, indicating that there are species-specific differences in TRAIL and receptor systems. In the present study, we demonstrated Immunohistochemical, Western immunoblotting, and reverse transcription-polymerase chain reaction analyses (RT-PCR) of TRAIL and DR4 in granulosa cells during follicular atresia in pig ovaries. For immunohistochemistry, pig ovaries obtained at a local slaughterhouse were fixed with 20% buffered formalin. For Western blotting and RT-PCR analysis, individual preovulatory antral follicles were dissected from the ovaries. Based on morphological and endocrinological criteria, the antral follicles were divided into three categories as follows: healthy, early stage of atresia, progressed stage of atresia. Significant increases were demonstrated in TRAIL protein and mRNA levels during atresia, but not in DR4 protein. Moreover in an in vitro apoptosis-inducing assay using cultured granulosa cells prepared from healthy follicles, we showed that more than 200ng/mL TRAIL could activate caspase-3 and induce apoptotic cell death in a dose-and time-dependent manner, but less than 100ng/mL of TRAIL could not induce apoptosis. When DcR1 was removed from the cell membrane of granulosa cells, a lower dose of TRAIL could induce apoptosis. The present findings suggested that the TRAIL can induce granulosa cell apoptosis, and that DcR1 blocks TRAIL-induced apoptosis in granulosa cells of healthy follicles in porcine ovaries.
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Iwai S, Ono M, Maeda A, Matsuzaki H, Kishida H, Okamoto H, Tokura Y. Ultrafast optical switching to a metallic state by photoinduced mott transition in a halogen-bridged nickel-chain compound. PHYSICAL REVIEW LETTERS 2003; 91:057401. [PMID: 12906630 DOI: 10.1103/physrevlett.91.057401] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Indexed: 05/24/2023]
Abstract
We demonstrate the ultrafast photoinduced Mott transition from a charge transfer insulator to a metal in a halogen-bridged Ni-chain compound by pump-probe reflection spectroscopy. Upon the irradiation of a 130-femtosecond laser pulse, the spectral weight of the gap transition is transferred to the inner-gap region. When the photoexcitation density exceeds 0.1/Ni site, the Drude-like high-reflection band appears in the infrared region, signaling the formation of a metallic state. The photogeneration of the metallic state and the subsequent recovery to the original gapped state occur within a few picoseconds.
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Maeda A, Aragane Y, Ueno K, Yamazaki F, Kawada A, Tezuka T. A case of naevus lipomatosus cutaneus superficialis of the scalp associated with pedunculated basal cell carcinoma. Br J Dermatol 2003; 148:1084-6. [PMID: 12786865 DOI: 10.1046/j.1365-2133.2003.05196.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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64
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Maeda A, Goto M, Zhang J, Bennet W, Groth CG, Korsgren O, Wennberg L. Immunosuppression with FTY720 and cyclosporine A inhibits rejection of adult porcine islet xenografts in rats. Transplantation 2003; 75:1409-14. [PMID: 12717240 DOI: 10.1097/01.tp.0000061770.39569.7f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Our aim was to evaluate the effect of FTY720 in discordant islet xenotransplantation. METHODS Fetal porcine islet-like cell clusters (ICCs) were transplanted into normoglycemic rats that were either left untreated or treated with FTY720 only, with FTY720 plus cyclosporine A (CsA) or with CsA only. Twelve or 24 days after transplantation, graft morphology was evaluated immunohistochemically. Furthermore, adult porcine islets (APIs) were transplanted into diabetic rats immunosuppressed with FTY720 plus CsA. Blood glucose and porcine C-peptide levels were monitored. RESULTS In untreated rats, the ICC xenografts were completely rejected after 12 days. Treatment with CsA had only a marginal effect on the rejection. In animals given FTY720, only the number of infiltrating cells was somewhat reduced. However, at 12 days, no intact ICCs remained. Immunosuppression with FTY720 plus CsA had a marked inhibitory effect on islet xenograft rejection and plentiful morphologically intact ICCs remained. Twelve days after transplantation, only occasional macrophages and T cells could be detected. At 24 days after transplantation, the findings were similar. Furthermore, diabetic rats transplanted with APIs and immunosuppressed with FTY720 plus CsA remained normoglycemic for 53.0+/-15.8 days. In fact, one animal remained normoglycemic for more than 100 days. Serum levels of porcine C-peptide remained at levels similar to those for human C-peptide in healthy individuals. CONCLUSIONS Immunosuppression with FTY720 plus CsA inhibited almost all morphological signs of pig-to-rat islet xenograft rejection for up to 24 days after transplantation. Diabetic rats transplanted with APIs and immunosuppressed with FTY720 plus CsA remained normoglycemic for 53.0+/-15.8 days.
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Nakagawa M, Ogura T, Maeda A, Kitagawa T. Transient resonance Raman spectra of neutral and alkaline bacteriorhodopsin photointermediates observed with a double-beam flow apparatus: presence of very fast decaying M412. Biochemistry 2002. [DOI: 10.1021/bi00429a061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kurihara T, Deguchi S, Kato J, Furakawa M, Tsuchiya M, Akimoto M, Ishiguro H, Hashimoto H, Niimi A, Maeda A, Shigemoto M, Yamashita K, Kawakami A, Umemura K, Nakashima M, Nakano T, Saniabadi AR. Impaired blood rheology by remnant-like lipoprotein particles: studies in patients with fatty liver disease. Clin Hemorheol Microcirc 2002; 24:217-25. [PMID: 11564910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Fatty liver disease (FLD) characterised by a high plasma levels of lipoproteins and remnant-like lipoproteins (RLP) is a risk factor for impaired microvascular blood flow, endothelial cell dysfunction and atherosclerosis. Using an immunoseparation technique with a gel mixture containing human monoclonal antibodies to apo A-I and apo B-100, we separated and measured RLP cholesterol (RLP-C) levels which reflect RLP in patients with FLD (n=20). Whole blood transit time (TT) was determined by a microchannel method (MC-FAN) which allows blood flow to be viewed via a microscope connected to an image display unit. RLP-C levels were higher (P<0.01) in FLD, 15.6 +/- 1.0 mg/dl compared with 4.8 +/- 0.5 mg/dl for controls (n=20). Similarly, TT was longer (P<0.01) in FLD, 284.5 +/- 26.1 sec/100 microl compared with 82.8 +/- 1.0 sec/100 microl for controls. Since the liver is a major site for RLP formation and degradation, it is affected to a greater extent in patients with FLD. It is likely that high levels of RLP can impair microvascular perfusion in the liver tissue and contribute to the development and progression of FLD.
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Kitano H, Matsuo R, Miwa K, Maeda A, Takenobu T, Iwasa Y, Mitani T. Evidence for insulating behavior in the electric conduction of (NH(3))K(3)C(60) systems. PHYSICAL REVIEW LETTERS 2002; 88:096401. [PMID: 11864035 DOI: 10.1103/physrevlett.88.096401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2001] [Indexed: 05/23/2023]
Abstract
Microwave study using the cavity perturbation technique revealed that the conductivity of the antiferromagnet (NH(3))K(3-x)Rb(x)C(60) at 200 K is already 3-4 orders of magnitude smaller than those of superconductors, K(3)C(60) and (NH(3))(x)NaRb(2)C(60), and that the antiferromagnetic compounds are insulators below 250 K without metal-insulator transitions. The striking difference in the magnitude of the conductivity between these materials strongly suggests that the Mott-Hubbard transition in the ammoniated alkali fullerides is driven by a reduction of lattice symmetry from face-centered-cubic to face-centered-orthorhombic, rather than by the magnetic ordering.
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Sasaki M, Maeda A, Sakamoto K, Fujimura A. Effect of bile acids on absorption of nitrendipine in healthy subjects. Br J Clin Pharmacol 2001; 52:699-701. [PMID: 11736882 PMCID: PMC2014563 DOI: 10.1046/j.0306-5251.2001.01489.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS To examine whether bile acids such as ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) can influence the absorption of nitrendipine, a highly lipophilic calcium channel blocker. METHODS Six healthy subjects received nitrendipine (10 mg) with and without UDCA (50 mg) and CDCA (200 and 600 mg) with an interval of 1 approximately 2 weeks between study phases. RESULTS Bile acids decreased the Cmax (ng ml(-1)) [control 10.9 +/- 5.8 (mean+/- s.d.), UDCA 5.0 +/- 4.7 (95% confidence interval for difference; 3.9, 7.8, P = 0.0006), CDCA (600 mg) 5.0 +/- 3.9 (2.6, 9.2, P = 0.0059)] and AUC (ng ml(-1) h) [(control; 60 +/- 36, UDCA 15 +/- 13 (20, 73, P = 0.0064), CDCA (600 mg) 19 +/- 19 (21, 63, P = 0.0038)] of nitrendipine, while elimination half-life remained unchanged. CONCLUSIONS These results suggest that the amount of nitrendipine absorbed was decreased when the drug was administered with UDCA and CDCA.
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Maeda A, Nakamura K, Higuchi S, Yuasa T, Motohashi Y. Postural sway during cane use by patients with stroke. Am J Phys Med Rehabil 2001; 80:903-8. [PMID: 11821671 DOI: 10.1097/00002060-200112000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To quantitatively evaluate the effects of body support with a cane on postural sway by measuring gravity-center sway of patients with stroke who reside at home. DESIGN The subjects were 41 patients with stroke and 36 healthy independent elderly people. Each subject stood in the standard Romberg position on a gravicorder under two conditions: without support and with a cane. RESULTS In both groups, the largest area of gravity-center sway occurred when the subjects stood without support. The area of gravity-center sway of the patients with stroke was significantly greater than that of the healthy independent elderly. In the patients with stroke group, the percentage decrease in the standing position with the cane was 58.0% in the men and 53.9% in the women, as opposed to 67.7% in the men and 67.8% in the women in the group of healthy independent elderly. CONCLUSION The authors quantitatively evaluated the effects of body support with a cane on postural sway of patients with stroke. The effect of body support with cane on postural sway of patients with stroke was more effective than that of healthy independent elderly.
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Okazaki T, Maeda A, Nishimura H, Kurosaki T, Honjo T. PD-1 immunoreceptor inhibits B cell receptor-mediated signaling by recruiting src homology 2-domain-containing tyrosine phosphatase 2 to phosphotyrosine. Proc Natl Acad Sci U S A 2001; 98:13866-71. [PMID: 11698646 PMCID: PMC61133 DOI: 10.1073/pnas.231486598] [Citation(s) in RCA: 616] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PD-1 is an immunoreceptor that belongs to the immunoglobulin (Ig) superfamily and contains two tyrosine residues in the cytoplasmic region. Studies on PD-1-deficient mice have shown that PD-1 plays critical roles in establishment and/or maintenance of peripheral tolerance, but the mode of action is totally unknown. To study the molecular mechanism for negative regulation of lymphocytes through the PD-1 receptor, we generated chimeric molecules composed of the IgG Fc receptor type IIB (Fc gamma RIIB) extracellular region and the PD-1 cytoplasmic region and expressed them in a B lymphoma cell line, IIA1.6. Coligation of the cytoplasmic region of PD-1 with the B cell receptor (BCR) in IIA1.6 transformants inhibited BCR-mediated growth retardation, Ca(2+) mobilization, and tyrosine phosphorylation of effector molecules, including Ig beta, Syk, phospholipase C-gamma 2 (PLC gamma 2), and ERK1/2, whereas phosphorylation of Lyn and Dok was not affected. Mutagenesis studies indicated that these inhibitory effects do not require the N-terminal tyrosine in the immunoreceptor tyrosine-based inhibitory motif-like sequence, but do require the other tyrosine residue in the C-terminal tail. This tyrosine was phosphorylated and recruited src homology 2-domain-containing tyrosine phosphatase 2 (SHP-2) on coligation of PD-1 with BCR. These results show that PD-1 can inhibit BCR signaling by recruiting SHP-2 to its phosphotyrosine and dephosphorylating key signal transducers of BCR signaling.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, Surface/genetics
- Antigens, Surface/metabolism
- Apoptosis Regulatory Proteins
- Calcium/metabolism
- Cell Division
- Humans
- Intracellular Signaling Peptides and Proteins
- Mice
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Phosphorylation
- Phosphotyrosine/metabolism
- Programmed Cell Death 1 Receptor
- Protein Phosphatase 2
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/metabolism
- Receptors, Antigen, B-Cell/metabolism
- Receptors, IgG/genetics
- Receptors, IgG/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, KIR
- SH2 Domain-Containing Protein Tyrosine Phosphatases
- Signal Transduction
- Tumor Cells, Cultured
- Tyrosine/metabolism
- src Homology Domains
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Yoshida T, Maeda A, Tani N, Sakai T. Promoter structure and transcription initiation sites of the human death receptor 5/TRAIL-R2 gene. FEBS Lett 2001; 507:381-5. [PMID: 11696376 DOI: 10.1016/s0014-5793(01)02947-7] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The death receptor 5 (DR5) is a receptor for tumor necrosis factor-related apoptosis-inducing ligand and is able to induce apoptosis in various tumor cells. The expression of DR5 is up-regulated at the transcriptional level by p53, genotoxic stress and so on. To investigate the structure of the DR5 gene promoter, we screened and sequenced a genomic clone containing the 5'-flanking region of the DR5 gene. RNase protection assays showed two major transcription start sites around -122 and -137 upstream of the translation initiation codon ATG. Transient transfections with serial 5'-deletion mutants identified the minimal promoter element spanning -198 to -116. Site-directed mutagenesis demonstrated that the DR5 gene promoter has no typical TATA-box, but has two Sp1 sites responsible for the basal transcription activity of the DR5 gene promoter.
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Maeda A. Internal water molecules as mobile polar groups for light-induced proton translocation in bacteriorhodopsin and rhodopsin as studied by difference FTIR spectroscopy. BIOCHEMISTRY. BIOKHIMIIA 2001; 66:1256-68. [PMID: 11743870 DOI: 10.1023/a:1013183302690] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
FTIR spectroscopy is advantageous for detecting changes in polar chemical bonds that participate in bacteriorhodopsin function. Changes in H-bonding of Asp85, Asp96, the Schiff base, and internal water molecules around these residues upon the formation of the L, M, and N photo-intermediates of bacteriorhodopsin were investigated by difference FTIR spectroscopy. The locations and the interactions of these water molecules with the amino acid residues were further revealed by use of mutant pigments. The internal water molecules in the cytoplasmic domain probably work as mobile polar groups in an otherwise apolar environment and act to stabilize the L intermediate, and carrying a proton between the Schiff base and the proton acceptor or donor. Similar internal water molecules were shown to be present in bovine rhodopsin.
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Nemoto-Sasaki Y, Mitsuki M, Morimoto-Tomita M, Maeda A, Tsuiji M, Irimura T. Correlation between the sialylation of cell surface Thomsen-Friedenreich antigen and the metastatic potential of colon carcinoma cells in a mouse model. Glycoconj J 2001; 18:895-906. [PMID: 12820723 DOI: 10.1023/a:1022252509765] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The cell surface glycosylation profiles of a liver metastatic colon carcinoma variant cell line, SL4 cells previously selected from colon 38 cells in vivo for liver colonization were investigated. Flowcytometric analysis was performed with 7 plant lectins and 10 carbohydrate specific monoclonal antibodies. The results showed that peanut agglutinin (PNA), Sambucus nigra agglutinin, Ulex europeus agglutinin-I, anti-LeX, anti-LeY, and anti-Le(b) antibodies bound to the parental colon 38 cells but not to SL4 cells. Another variant cell line was selected in vitro for the paucity of cell surface PNA-binding sites using a magnetic cell sorter and was designated as 38-N4 cells. The binding profiles of plant lectins and carbohydrate-specific antibodies to 38-N4 cells were very similar to those of SL4 cells. After intrasplenic injections, metastatic ability of 38-N4 cells was higher than that of colon 38 cells. PNA binding to SL4 cells and 38-N4 cells was detected after sialidase treatment of these cells, indicating increased sialylation of Thomsen-Friedenreich antigen in these cells. The mRNA levels of sialyltransferases, ST3Gal I, ST3Gal II, ST6GalNAc I, and ST6GalNAc II, were compared. The level of ST3Gal II mRNA was elevated in both SL4 cells and 38-N4 cells, whereas the level of ST6GalNAc II mRNA was elevated in 38-N4 cells compared with colon 38 cells. According to the expression array analysis, there are other glycosyltransferase genes differentially expressed between SL4 and colon 38 cells, yet their involvement in the altered glycosylation in these cells is unclear.
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Sasaki M, Maeda A, Fujimura A. Influence of diltiazem on the pharmacokinetics of amlodipine in elderly hypertensive patients. Eur J Clin Pharmacol 2001; 57:85-6. [PMID: 11372598 DOI: 10.1007/s002280000241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Ohguro H, Ogawa K, Maeda T, Maruyama I, Maeda A, Takano Y, Nakazawa M. Retinal dysfunction in cancer-associated retinopathy is improved by Ca(2+) antagonist administration and dark adaptation. Invest Ophthalmol Vis Sci 2001; 42:2589-95. [PMID: 11581204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
PURPOSE It was recently found that recoverin acts as an autoantigen recognized by sera of patients with cancer-associated retinopathy (CAR), and that CAR-like retinal dysfunction is produced by intravitreous administration of anti-recoverin antibody in Lewis rat eyes. To examine the pathologic molecular mechanism of CAR, and to elucidate an effective therapy for CAR, the function and morphology of CAR were compared with those of phototoxic retinal damage, another form of photoreceptor dysfunction, and the effect of nilvadipine, a Ca(2+) antagonist, on the retinal degenerations was studied, using these models. METHODS Under different illumination conditions and/or medication with nilvadipine, the functional and morphologic properties of the retinas were evaluated after intravitreous injection of anti-recoverin antibody into Lewis rat eyes (six rats, 12 eyes in each experimental condition), using electroretinogram (ERG), rhodopsin phosphorylation, and light microscopy. RESULTS Anti-recoverin antibody administered into the vitreous of Lewis rat eyes induced a significant decrease and increase of ERG responses and rhodopsin phosphorylation levels, respectively, under cyclic or continuous light. Similar changes were observed in eyes of rats bred under continuous illumination that did not receive anti-recoverin antibodies. However, anti-recoverin antibody-induced retinal dysfunctions were not observed in rat eyes under dark conditions. Administration of nilvadipine, a Ca(2+) antagonist, to the anti-recoverin antibody-treated rats and rats with phototoxic retinal dysfunction caused significant improvement of the deterioration of ERG and normalization of rhodopsin phosphorylation. CONCLUSIONS The present data indicate that anti-recoverin antibody-induced retinal dysfunction was functionally similar to phototoxic retinal dysfunction and was markedly suppressed under dark conditions or by systemic administration of a Ca(2+) antagonist.
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