Biomedical subjects

M Yoshida

Publications and source records attributed to M Yoshida.

At least 19 recordsLinked to original sources

PubMed2006

Ergosterol peroxide from an edible mushroom suppresses inflammatory responses in RAW264.7 macrophages and growth of HT29 colon adenocarcinoma cells.

BACKGROUND AND PURPOSE: 5alpha,8alpha-Epidioxy-22E-ergosta-6, 22-dien-3beta-ol (ergosterol peroxide) is a major antitumour sterol produced by edible or medicinal mushrooms. However, its molecular mechanism of action has yet to be determined. Here, we examine the anticancer and anti-inflammatory effects of ergosterol peroxide. EXPERIMENTAL APPROACH: After treating RAW264.7 macrophages with LPS and purified ergosterol peroxide or ergosterol, we determined LPS-induced inflammatory cytokines, nuclear DNA binding activity of transcription factors and phosphorylation of MAP kinases (MAPKs). HT29 colorectal adenocarcinoma cells were treated with ergosterol peroxide for 5 days. To investigate the antitumour properties of ergosterol peroxide, we performed DNA microarray and RT-PCR analyses and determined the reactive oxygen species (ROS) in HT29 cells. KEY RESULTS: Ergosterol peroxide suppressed LPS-induced TNF-alpha secretion and IL-1alpha/beta expression in RAW264.7 cells. Ergosterol peroxide and ergosterol suppressed LPS-induced DNA binding activity of NF-kappaB and C/EBPbeta, and inhibited the phosphorylation of p38, JNK and ERK MAPKs. Ergosterol peroxide down-regulated the expression of low-density lipoprotein receptor (LDLR) regulated by C/EBP, and HMG-CoA reductase (HMGCR) in RAW264.7 cells. In addition, ergosterol peroxide showed cytostatic effects on HT29 cells and increased intracellular ROS. Furthermore, ergosterol peroxide induced the expression of oxidative stress-inducible genes, and the cyclin-dependent kinase inhibitor CDKN1A, and suppressed STAT1 and interferon-inducible genes. CONCLUSION AND IMPLICATION: Our results suggest that ergosterol peroxide and ergosterol suppress LPS-induced inflammatory responses through inhibition of NF-kappaB and C/EBPbeta transcriptional activity, and phosphorylation of MAPKs. Moreover, ergosterol peroxide appears to suppress cell growth and STAT1 mediated inflammatory responses by altering the redox state in HT29 cells.

Adenocarcinoma↗

PubMed2006

Diurnal differences in the supply of glucomannans and xylans to innermost surface of cell walls at various developmental stages from cambium to mature xylem in Cryptomeria japonica.

We investigated the diurnal differences in the innermost surface of tracheid cell walls at various developmental stages from cambium to mature xylem. Cryptomeria japonica saplings were cultivated in a growth chamber with a light cycle set at 14 h of light and 10 h of darkness. Samples were collected from the saplings during both the light and dark periods. The innermost surface of cell walls was immunogold-labeled with anti-glucomannan or anti-xylan antiserum and was observed by field emission scanning electron microscopy. Diurnal differences in the aspect of the innermost surface of cell walls were seen only in S(2)-layer-forming tracheids; cellulose microfibrils were clearly evident during the light period, and amorphous material containing glucomannans and xylans was prevalent during the dark period. Cellulose microfibrils were present at the primary-wall formation and S(1)-layer-forming stages, and many warts were observed in the mature tracheids, regardless of the time of sampling. The densities of labeled glucomannans on the innermost surface of cell walls in S(1)- and S(2)-forming tracheids and of labeled xylans in S(2)-forming tracheids during the dark period were significantly higher than those during the light period. These results suggest a diurnal periodicity in the supply of cell wall matrix containing hemicellulose to the innermost surface of developing secondary walls.

Cell Wall↗

PubMed2006

Efficacy of computer-assisted pedicle screw insertion for cervical instability in RA patients.

We evaluated the efficacy of the computer-assisted cervical pedicle screw insertion, compared with those inserted without the help of the system on the cervix of rheumatoid arthritis (RA) patients. Eighty-six cervical pedicle screws were inserted without the help of the system. Of the 86, 59 screws were in non-RA patients with degenerative spine, and 27 were in RA patients. The accuracy of the screw insertions was evaluated by a CT-based method. Then, 25 screws were inserted with the system into the cervical spines between C2 and C6 in RA patients (Navigation group). The efficacy of the system was assessed by the CT-based method, compared with 27 screws inserted without the system (Conventional group). The screws in RA patients tended to be more deviated than those in non-RA patients. In Conventional group, four screws (15%) were placed far laterally, and two (7%), far medially. In contrast, no screw was placed far laterally or medially in Navigation group (P < 0.05).

Adult↗

PubMed2006

Involvement of protein phosphatase 2A nuclear accumulation and subsequent inactivation of activator protein-1 in leptomycin B-inhibited cyclin D1 expression.

Leptomycin B (LMB) is a Streptomyces metabolite that causes the specific inhibition of the nuclear export of proteins containing a nuclear export signal (NES). LMB was reported to inhibit cell cycle progression in fission yeast and mammalian cells, however, the mechanism underlying LMB-induced cell cycle arrest is still obscure. In this study, we found that in serum-starved NIH3T3 cells, LMB inhibited serum-induced cyclin D1 expression at the level of transcription. However, this inhibition was reversed by inhibitors of protein phosphatase 2A (PP2A). Furthermore, we found that PP2A accumulated in the nucleus upon treatment with LMB. The finding prompted us to identify the functional NES in PP2A catalytic subunit alpha. These results indicated that LMB inhibited the chromosomal region maintenance 1 (CRM1)-dependent nuclear export of PP2A, resulting in sustained dephosphorylation in the nucleus. Although phosphorylation of c-Jun at Ser-63 is required for activator protein 1 (AP-1)-dependent expression of cyclin D1, it decreased in LMB-treated cells compared to untreated cells. Moreover, the inhibitors of PP2A restored the levels of c-Jun phosphorylated at Ser-63. We propose that inhibition of cyclin D1 expression by LMB is mediated by the LMB-induced nuclear accumulation of PP2A, leading to sustained dephosphorylation of c-Jun at Ser-63, which leads to inactivation of the transcription of the AP-1-responsive cyclin D1 gene.

Animals↗

PubMed2006

Observation and control of transverse energy-transport barrier due to the formation of an energetic-electron layer with sheared ExB flow.

Off-axis electron-cyclotron heating in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, producing a localized bumped ambipolar potential Phi(C), forms a strong shear of radial electric fields E(r) and peaked vorticity with the direction reversal of E(r)xB sheared flow near the Phi(C) peak. Intermittent vortexlike turbulent structures near the layer are suppressed in the central cell by this actively produced transverse energy-transport barrier; this results in T(e) and T(i) rises surrounded by the layer.

Journal Article↗

PubMed2006

Comparison of posterior capsule opacification between fellow eyes with two types of acrylic intraocular lens.

PURPOSE: To compare the degree of posterior capsule opacification (PCO) and visual function between fellow eyes that received two different types of hydrophobic acrylic intraocular lenses (IOLs). METHODS: Forty-five patients underwent bilateral phacoemulsification and implantation of an Alcon AcrySof IOL (MA60AC) in one eye and an AMO Sensar IOL (AR40e) in the fellow eye. The PCO density value was measured using the Scheimpflug videophotography system at 1, 6, 12, and 24 months after surgery. The incidence of eyes that required a neodymium:YAG (Nd:YAG) laser capsulotomy, visual acuity, and contrast sensitivity with and without a glare source were also examined. RESULTS: The mean PCO value did not show a significant increase in either the AcrySof MA60AC or Sensar AR40e IOL groups, and was similar between the two groups throughout the 24-month follow-up period. The incidence of Nd:YAG laser capsulotomy was also the same between the groups. No significant difference was found in mean visual acuity between the two IOL groups during the follow-up, and there was no significant difference in photopic or mesopic contrast visual acuity with and without a glare source at 1 and 24 months after surgery. CONCLUSION: The degree of PCO in eyes with an AcrySof IOL are almost the same as that in eyes with a Sensar IOL, with the results that visual acuity and contrast sensitivity with and without glare are similar.

Acrylic Resins↗

PubMed2006

Regulation of SV40 large T-antigen stability by reversible acetylation.

Reversible acetylation on protein lysine residues has been shown to regulate the function of both nuclear proteins such as histones and p53 and cytoplasmic proteins such as alpha-tubulin. To identify novel acetylated proteins, we purified several proteins by the affinity to an anti-acetylated-lysine antibody from cells treated with trichostatin A (TSA). Among the proteins identified, here we report acetylation of the SV40 large T antigen (T-Ag). The acetylation site was determined to be lysine-697, which is located adjacent to the C-terminal Cdc4 phospho-degron (CPD). Overexpression of the CBP acetyltransferase acetylated T-Ag, whereas HDAC1, HDAC3 and SIRT1 bound and deacetylated T-Ag. The acetylation and deacetylation occurred independently of p53, a binding partner of T-Ag, but the acetylation was enhanced in the presence of p53. T-Ag in the cells treated with TSA and NA or the acetylation mimic mutant (K697Q) became unstable in COS-7 cells, suggesting that acetylation regulates stability of T-Ag. Indeed, NIH3T3 cells stably expressing K697Q showed decreased anchorage-independent growth compared with those expressing wild type or the K697R mutant. These results demonstrate that acetylation destabilizes T-Ag and regulates the transforming activity of T-Ag in NIH3T3 cells.

Acetylation↗

PubMed2006

Postprandial changes in plasma concentrations of growth hormone and ghrelin around weaning in the goat.

We measured and compared plasma levels of GH and ghrelin in response to feeding in 4-week-old (milk replacer-fed) and 13-week-old (alfalfa hay cube-fed) goats, in order to elucidate whether or not the postprandial regulation of these hormone levels changes around weaning. Furthermore, we examined the effects of suckling from the dam or intravenous glucose administration on both hormone and insulin levels in kids. In 4-week-old goats, feeding of a milk replacer diet significantly increased plasma GH levels without changing level of ghrelin. In contrast, in 13-week-old goats, feeding of hay cubes did not change the levels of either ghrelin or GH. Suckling of milk directly from the dams significantly increased the levels of GH and insulin, but not ghrelin, in kids. Finally, intravenous injection of glucose (0.625 mmol/kg BW) did not cause any significant increase in the levels of GH or ghrelin, despite a significant increase in the levels of insulin and glucose. From these results, we conclude that the regulatory system of the somatotropic axis is altered by weaning or weaning-associated processes, and that ghrelin levels may not be involved in this alteration in young goats.

Animals↗

PubMed2006

Nucleolin is involved in interferon regulatory factor-2-dependent transcriptional activation.

We have previously shown that interferon regulatory factor-2 (IRF-2) is acetylated in a cell growth-dependent manner, which enables it to contribute to the transcription of cell growth-regulated promoters. To clarify the function of acetylation of IRF-2, we investigated the proteins that associate with acetylated IRF-2. In 293T cells, the transfection of p300/CBP-associated factor (PCAF) enhanced the acetylation of IRF-2. In cells transfected with both IRF-2 and PCAF, IRF-2 associated with endogenous nucleolin, while in contrast, minimal association was observed when IRF-2 was transfected with a PCAF histone acetyl transferase (HAT) deletion mutant. In a pull-down experiment using stable transfectants, acetylation-defective mutant IRF-2 (IRF-2K75R) recruited nucleolin to a much lesser extent than wild-type IRF-2, suggesting that nucleolin preferentially associates with acetylated IRF-2. Nucleolin in the presence of PCAF enhanced IRF-2-dependent H4 promoter activity in NIH3T3 cells. Nucleolin knock-down using siRNA reduced the IRF-2/PCAF-mediated promoter activity. Chromatin immunoprecipitation analysis indicated that PCAF transfection increased nucleolin binding to IRF-2 bound to the H4 promoter. We conclude that nucleolin is recruited to acetylated IRF-2, thereby contributing to gene regulation crucial for the control of cell growth.

3T3 Cells↗

PubMed2006

Carbocisteine inhibits rhinovirus infection in human tracheal epithelial cells.

The aim of the study was to examine the effects of a mucolytic drug, carbocisteine, on rhinovirus (RV) infection in the airways. Human tracheal epithelial cells were infected with a major-group RV, RV14. RV14 infection increased virus titres and the cytokine content of supernatants. Carbocisteine reduced supernatant virus titres, the amount of RV14 RNA in cells, cell susceptibility to RV infection and supernatant cytokine concentrations, including interleukin (IL)-6 and IL-8, after RV14 infection. Carbocisteine reduced the expression of mRNA encoding intercellular adhesion molecule (ICAM)-1, the receptor for the major group of RVs. It also reduced the supernatant concentration of a soluble form of ICAM-1, the number and fluorescence intensity of acidic endosomes in the cells before RV infection, and nuclear factor-kappaB activation by RV14. Carbocisteine also reduced the supernatant virus titres of the minor group RV, RV2, although carbocisteine did not reduce the expression of mRNA encoding a low density lipoprotein receptor, the receptor for RV2. These results suggest that carbocisteine inhibits rhinovirus 2 infection by blocking rhinovirus RNA entry into the endosomes, and inhibits rhinovirus 14 infection by the same mechanism as well as by reducing intercellular adhesion molecule-1 levels. Carbocisteine may modulate airway inflammation by reducing the production of cytokines in rhinovirus infection.

Aged↗

PubMed2006

Intercellular adhesion molecule-1 mediates the inhibitory effects of hyaluronan on interleukin-1beta-induced matrix metalloproteinase production in rheumatoid synovial fibroblasts via down-regulation of NF-kappaB and p38.

OBJECTIVE: In rheumatoid arthritis (RA), it is well known that rheumatoid synovial fibroblasts (RSF) produce matrix metalloproteinases (MMPs) when stimulated with proinflammatory cytokines such as interleukin-1beta (IL-1beta), which causes joint destruction. We have previously shown that hyaluronan (HA) inhibits IL-1beta actions in RSF via CD44, the principal HA receptor. However, CD44 mediates HA effects only partially, and intracellular events after the HA binding to its receptors remain unclear. We investigated the role of intercellular adhesion molecule-1 (ICAM-1), another cell surface receptor for HA, and the intracellular signalling pathways in the actions of HA. METHODS: RSF were isolated from rheumatoid synovial tissues by enzymatic digestion and cultured in monolayers. The confluent cells were incubated for 48 h with IL-1beta, IL-1beta in the presence of HA, or IL-1beta in the presence of HA with pretreatment with anti-ICAM-1 antibody. Secretion of MMP-1 and MMP-3 was analysed by immunoblotting and immunofluorescence cytochemistry. Immunofluorescence cytochemistry was also performed to evaluate binding of HA to ICAM-1. The phosphorylation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases (MAPKs) was analysed by immunoblotting. RESULTS: Production of MMP-1 and MMP-3 by RSF was stimulated by IL-1beta. HA at > or =2 mg/ml significantly inhibited MMP production induced by IL-1beta in a dose-dependent manner. Moreover, pretreatment with anti-ICAM-1 antibody at 50 mug/ml significantly blocked the effects of HA on the actions of IL-1beta on RSF, as shown by immunoblotting and immunofluorescence cytochemistry. Another immunofluorescence cytochemistry study demonstrated that HA bound RSF via ICAM-1. Inhibition studies revealed the requirement of NF-kappaB, p38 and c-jun NH2-terminal kinase (JNK) for IL-1beta-induced MMP production. IL-1beta activated all three pathways, whereas HA down-regulated their phosphorylation. Pretreatment with anti-ICAM-1 antibody reversed the inhibitory effects of HA on the activation of NF-kappaB and p38 without affecting JNK. CONCLUSION: HA suppresses IL-1beta-enhanced MMP-1 and MMP-3 synthesis in RSF via ICAM-1 through down-regulation of NF-kappaB and p38. Intra-articular injection of HA of high molecular weight may work through such a mechanism in RA joints.

Arthritis, Rheumatoid↗

PubMed2006

State-of-art methodology of marine natural products chemistry: structure determination with extremely small sample amounts.

Structure elucidation studies on natural products are reviewed emphasizing extremely small sample amounts. Previous studies on insect pheromones, periplanones, and bean-originating kairomones, glycinoeclepins, are described briefly. Recent examples are selected from marine natural products such as ciguatoxin, dolastatin-3, and aurisides. A more detailed description is given of a sperm-activating and attracting factor (SAAF), which may be the smallest sample amount used in the structure elucidation of novel non-peptidic natural products. SAAF was isolated from the eggs of the ascidian, Ciona intestinalis, and its structure was deduced with only approximately 4 microg (6 nmol) of sample. Based upon the proposed structure, two epimers were synthesized from chenodeoxycholic acid in 17 steps, leading to the identification of SAAF as a novel sterol sulfate.

Animals↗

PubMed2006

Acid sphingomyelinase deficiency: cardiac dysfunction and characteristic findings of the coronary arteries.

Two sisters with type B Niemann-Pick disease (genotype: S436R/S436R) showed cardiac dysfunctions, not secondary to pulmonary disease, at the beginning of the third decade. In the younger sister, myocardial dysfunction was refractory to treatment, resulting in death. At autopsy, the distal branches of the coronary arteries showed narrowing of the arterial lumina due to swelling of the medial and intimal smooth-muscle cells. This is the first report describing characteristic findings of coronary arteries in type B Niemann-Pick disease.

Adult↗

PubMed2006

Effect of plant sterols and glucomannan on lipids in individuals with and without type II diabetes.

OBJECTIVE: The purpose of this study was to determine whether supplements of plant sterols and/or glucomannan improve lipid profile and cholesterol biosynthesis in mildly hypercholesterolemic type II diabetic and non-diabetic subjects and to compare the response of these two subject groups to the treatments. DESIGN: A randomized, crossover study consisting of four phases of 21 days, with each phase separated by a 28-day washout. SETTING: The Mary Emily Clinical Nutrition Research Unit of McGill University. SUBJECTS: Eighteen non-diabetic individuals and 16 type II diabetic individuals aged 38-74 years. INTERVENTIONS: Subjects were supplemented with plant sterols (1.8 g/day), glucomannan (10 g/day), a combination of glucomannan and plant sterols, and a placebo, provided in the form of bars. RESULTS: Overall plasma cholesterol concentrations were lowered (P<0.05) after combination treatment (4.72+/-0.20 mmol/l) compared to control (5.47+/-0.18 mmol/l). Plasma low-density lipoprotein (LDL) cholesterol concentrations were decreased (P<0.05) after glucomannan (3.16+/-0.14 mmol/l) and combination treatments (2.95+/-0.16 mmol/l) compared to control (3.60+/-0.16 mmol/l). The results of lipid profiles did not differ between subject groups. Overall plasma lathosterol concentrations, an index of cholesterol biosynthesis, were lowered (P<0.05) after the combination treatment compared to the plant sterol treatment. CONCLUSIONS: The results suggest that glucomannan and a combination of glucomannan and plant sterols substantially improves plasma LDL cholesterol concentrations. SPONSORSHIP: Forbes Medi-Tech Inc., Vancouver, British Columbia, Canada.

Adult↗

PubMed2006

Effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma total homocysteine concentrations in young Japanese male subjects.

OBJECTIVE: To investigate the effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma plasma total homocysteine (tHcy) concentrations in young Japanese male subjects. DESIGN: In a double blind, randomized controlled trial. INTERVENTION: Subjects were randomly assigned to one of four groups and received a placebo (control group), 800 microg/day folic acid (FA group), 8.4 mg/day riboflavin (R group), or both (FAR group) for 2 weeks. SETTING: Tokyo, Japan. SUBJECTS: In total, 32 healthy male volunteers aged 20-29 years. RESULTS: At the end of the 2 week supplementation period, the tHcy concentration decreased significantly in the FA group. Serum folate concentrations had increased between 2.7 and 2.0-fold in the FA and FAR groups, respectively, but the mean within-group changes in serum folate and plasma tHcy concentrations did not differ between these two groups. At the end of the study, alanine amino transferase was decreased in the R and FAR groups, while alanine amino transferase was increased in the FA group. CONCLUSION: Supplementation with folic acid, 800 microg/day, for 2 weeks, increased the serum and red blood cell folate concentrations and decreased the plasma tHcy concentrations in healthy young male subjects. Riboflavin supplementation may have blunted the effect of folic acid, which resulted in a diminished reduction of tHcy in our subjects.

Adult↗

PubMed2006

Cardiac lipoma in the ventricular septum--a case report.

We report a case of a cardiac lipoma in the interventricular septum complicated with mitral regurgitation and atrial fibrillation in a 74-year-old woman. Surgical excision of the tumor was performed with mitral annuloplasty and a Maze III procedure. She continues to do well 7 months postoperatively.

Aged↗

PubMed2006

Posterior endoscopic surgery for lumbar disc herniation with contralateral symptoms - a report of two cases.

We report two cases of lumbar disc herniation with contralateral nerve root involvement, surgically treated with a microendoscopic disectomy system (METRx-MED system). The nerve root of the symptomatic side (contralateral to the side of the disc herniation) had been compressed to the superior facet by herniated disc from the opposite side. Endoscopic observation revealed inflammatory findings of the nerve root on the symptomatic side, such as fibrosis, adhesion, redness and swelling. In contrast, on the non-symptomatic side (ipsilateral side of the disc herniation), the nerve root had been merely compressed by the herniated disc but did not demonstrate any inflammatory findings. Excision of the herniated disc and decompression of the non-symptomatic nerve root should be done first, approaching from the disc herniation side. After that, through the same approach, the nerve root of the opposite (symptomatic) side should be decompressed.

Adolescent↗

PubMed2006

Sensitive and rapid diagnosis of human parvovirus B19 infection by loop-mediated isothermal amplification.

BACKGROUND: Human parvovirus B19 (B19) infections exhibit various skin manifestations that are similar to and hence hard to distinguish from many other skin diseases. The virological diagnosis of B19 infection is usually based on time-consuming serological tests and polymerase chain reaction (PCR). OBJECTIVES: In this study, a DNA amplification method, loop-mediated isothermal amplification (LAMP), was used for the diagnosis of B19 infection and was compared with PCR. METHODS: Ten patients with acute B19 infection and 16 patients with other skin diseases were enrolled. Sera and pharyngeal swabs were used directly as the templates in LAMP. The LAMP reaction was carried out at 63 degrees C for 1 h in a heat block. The reaction products were judged visually, by adding SYBR Green I into the tubes, and by gel electrophoresis. RESULTS: B19 DNA was detected by LAMP in 10 sera and all of seven tested pharyngeal swabs of 10 patients with acute B19 infection but not in samples from 16 patients with other skin diseases. The results were in agreement with those obtained by PCR except for one case. The reason for the single discrepancy may be that the sensitivity of LAMP is 10(2) times higher than PCR. CONCLUSIONS: Detection of B19 DNA by LAMP in serum and especially in the pharynx is a rapid and convenient method for the diagnosis of acute B19 infection.

Acute Disease↗