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Biomedical subjects

Minoru Yoshida

Publications and source records attributed to Minoru Yoshida.

At least 55 records · Page 3Linked to original sources
PubMed2005

Effects of administration of beta-carotene, ascorbic acid, persimmons, and pods on antioxidative ability in UV-irradiated ODS rats.

To evaluate the effects of supplementing diets with carotenoid and ascorbic acid (AsA) on the antioxidative ability of Osteogenic Disorder-Shionogi (ODS) rats, we added synthetic beta-carotene (betaC), AsA, and powders of persimmon (Ka) and pods (Po) containing betaC and AsA to the diet and obtained the following results. The urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration was low in the -betaC.AsA and +AsA groups but high in the +betaC.AsA, +Ka, and +Po groups. The thiobarbituric acid-reactive substances (TBARS) in both the liver and skin were higher in the -betaC.AsA group than in the +betaC.AsA group and were low in the +Ka and +Po groups. As antioxidant enzymes, glutathione peroxidase (GSH-Px) activity was high in the +betaC.AsA group, low in the -beta3C.AsA group in both the skin and liver, and also high in the + Ka and +Po group in the liver. Superoxide dismutase (SOD) activity was high in the -betaC.AsA group and low in the +betaC.AsA and +Ka groups in both the skin and liver. Catalase (CAT) activity in the liver was low in the -betaC.AsA, +AsA, and +betaC groups and high in the +betaC.AsA and +Po groups. These results confirmed that the administration of betaC, AsA, and persimmons and pods increases antioxidative ability in the skin and liver of ultraviolet-b(UV-B)-irradiated ODS rats.

Animals↗
PubMed2005

Involvement of nuclear accumulation of heat shock protein 27 in leptomycin B-induced apoptosis in HeLa cells.

Leptomycin B (LMB) is a Streptomyces metabolite that inhibits the chromosomal region maintenance (CRM)1-dependent nuclear export of proteins. It also induces apoptosis in several types of cancer cells, by a yet undefined mechanism. We used a functional proteomics approach to delineate the pathways and mediators involved in LMB-induced apoptosis in HeLa cells. Using two-dimensional gel electrophoresis, we searched for proteins accumulated in the nuclei of HeLa cells upon LMB treatment. Among such proteins we found prohibitin and Heat shock protein (Hsp)27, identified by peptide mass fingerprinting and mass spectrometry. Immunocytochemistry was carried out to confirm the LMB-induced nuclear accumulation of these two proteins in HeLa cells. Furthermore, we found that the cytoplasmic expression of Hsp27, but not prohibitin, partially inhibited LMB-induced apoptosis, indicating that nuclear sequestration of Hsp27 was, at least in part, involved in the apoptosis.

Antibiotics, Antineoplastic↗
PubMed2005

Inhibition of protein synthesis and activation of stress-activated protein kinases by onnamide A and theopederin B, antitumor marine natural products.

During the course of screening for the agents that activate transforming growth factor-beta (TGF-beta) signaling cascade, onnamide A and theopederin B, heterocyclic compounds related to mycalamides from a marine sponge, were found to induce plasminogen activator inhibitor-1 (PAI-1) promoter-derived gene expression in Mv1Lu cells. The maximum induction of the PAI-1 promoter by onnamide A and theopederin B was observed at the concentrations of 50 nM and 2 nM, respectively. These compounds strongly inhibited protein synthesis at the 50% inhibitory concentrations of 30 nM for onnamide A and 1.9 nM for theopederin B, and induced activation of p38 mitogen-activated protein kinase and c-Jun NH2-terminal protein kinase (JNK). Anisomycin, a well-known inducer of ribotoxic stress that inhibits protein synthesis and activates both p38 kinase and JNK, also activated PAI-1 gene expression. Furthermore, PAI-1 expression by onnamide A, theopederin B, and anisomycin was inhibited by SB202190 and SP600125, specific inhibitors of stress-activated protein kinases. Onnamide A and theopederin B were cytotoxic to a variety of cell lines and strongly induced apoptosis in HeLa cells within 24 h, which was accompanied by the sustained activation of p38 kinase and JNK. These results suggest that onnamide A and theopedirin B trigger a ribotoxic stress-like response, thereby inducing p38 kinase and JNK activation, the kinase-dependent PAI-1 gene expression, and apoptosis.

Animals↗
PubMed2005

Negative regulation of Gli1 and Gli2 activator function by Suppressor of fused through multiple mechanisms.

During animal development, the Hedgehog (Hh) signal transduction pathway plays critical roles in cell fate determination and tissue patterning. In humans, aberrant Hh signaling has been linked to several genetic disorders and cancers. Binding of Hh to its receptor initiates a signaling cascade, which ultimately results in the activation of the Gli/Ci transcription factors. Suppressor of fused (Su(fu)) is a Gli/Ci-interacting protein, which acts as a negative regulator of Hh signaling in Drosophila and vertebrates. Su(fu) is also implicated as a tumor suppressor as its mutations have been found in medulloblastoma and prostate cancer. Su(fu) is thought to act by preventing the nuclear accumulation of Gli/Ci, however, mechanistic insight into its mode of action has remained elusive. We demonstrate here that Su(fu) prevents the nuclear accumulation of Gli1 and Gli2 through multiple mechanisms. While Su(fu) itself is not subject to CRM1-dependent regulation, Su(fu) sequesters Gli1 in the cytoplasm mostly through a mechanism that depends on the activity of the nuclear export protein CRM1. In contrast, CRM1-mediated export is not required for Su(fu) to sequester Gli2. Furthermore, we show that the N-terminus of Su(fu) is sufficient for Gli inactivation in the absence of cytoplasmic sequestration. Together, these observations reveal that Su(fu) regulates the activity of Gli1 and Gli2 through distinct cytoplasmic and nuclear mechanisms.

Active Transport, Cell Nucleus↗
PubMed2005

Linkage mapping of AFLP and microsatellite DNA markers with the body color- and sex-determining loci in the guppy (Poecilia reticulata).

The guppy is an ornamental fish species that exhibits various phenotypic characteristics, such as body color and fin-shape. Although linkage relationships of a limited number of phenotypic traits have already been investigated, the association between phenotypic and molecular markers is still unknown. We constructed a total of 35 linkage groups for the guppy using 186 polymorphic loci of AFLP and microsatellite DNA. The locus related to the yellow body color was linked with ten markers and the sex-determination locus was linked with five markers.

Animals↗
PubMed2005

[Effectiveness of neoadjuvant chemotherapy for the patients with locally invasive bladder cancer].

OBJECTIVE: To know the survival and prognostic factors of the patients who received radical cystectomy with or without neoadjuvant cisplatin-based chemotherapy. METHODS: Between 1977 and 2001, 201 patients underwent radical cystectomy at Yokohama City University and Yokosuka Kyosai Hospital whose tumor were clinically diagnosed as locally invasive bladder cancer (T2-4NxM0). Survival rates and 9 prognostic factors (Age, Size, Multiplicity, Type, Grade, p-stage, n,neoadjuvant chemotherapy, adjuvant chemotherapy) were analysed by Kaplan-Meier methods and Cox-proportional hazard model. RESULTS: The independent prognostic factors of these patients were size, multiplicity, type, grade, p-stage, n, neoadjuvant by univariate analysis. Of these 7 factors, n, neoadjuvant, p-stage and size are significant by multivariate analysis. Survival of the patients who received neoadjuvant cisplatin-based chemotherapy followed cystectomy is better than cystectomy only group by Kaplan-Meier method. CONCLUSIONS: From these rusults, neoadjuvant cisplatin-based chemotherapy play some role for survival of the patients with invasive bladder cancer.

Adult↗
PubMed2005

Successful recovery from interstitial pneumonitis, induced by bicalutamide and leuprorelin acetate given as treatment for prostate cancer.

We report a case of interstitial pneumonitis induced by bicalutamide and/or leuprorelin acetate given as therapy for prostate cancer, in which the pneumonitis was successfully managed by steroid treatment. Steroids were given promptly on the day following onset of pneumonitis, and the patient (72 years old) recovered almost completely within one and a half months. Interstitial pneumonitis, induced by hormone treatment given for prostate cancer, is a reversible condition and a quick diagnosis followed by prompt, proper treatment is important to ensure a successful recovery. The patient had been free of interstitial pneumonitis for 14 months, but died of pneumothorax.

Adenocarcinoma↗
PubMed2005

Methotrexate suppresses inflammatory agonist induced interleukin 6 synthesis in osteoblasts.

OBJECTIVE: Interleukin 6 (IL-6) is a pleiotropic cytokine that plays a crucial role in the pathogenesis of rheumatoid arthritis (RA). In bone metabolism, it is known that IL-6 is produced and secreted by osteoblasts, and that IL-6 induces osteoclast formation and stimulates bone resorption. Various bone inflammatory agonists such as tumor necrosis factor-alpha (TNF-alpha), IL-1alpha, prostaglandin D2 (PGD2), PGE2, and PGF2alpha, which play important roles in the pathogenesis of RA, induce IL-6 synthesis in osteoblast-like MC3T3-E1 cells. Low dose methotrexate (MTX) is currently used for treatment of patients with RA. We investigated the effect of MTX on IL-6 synthesis induced by these agents in MC3T3-E1 cells. METHODS: Cultured cells were pretreated with various doses of MTX, and then stimulated by these inflammatory agonists. The IL-6 in the conditioned medium was measured by IL-6 enzyme immunoassay. RESULTS: MTX significantly suppressed IL-6 synthesis stimulated by these agonists in a dose-dependent manner, although MTX alone had no effect on the levels of IL-6. In addition, MTX significantly inhibited the enhancement by IL-17 of TNF-alpha-stimulated IL-6 synthesis. MTX reduced the levels of IL-6 induced by 12-O-tetradecanoylphorbol 13-acetate, a direct activator of protein kinase C (PKC), suggesting that MTX inhibits PKC signals for IL-6 synthesis. CONCLUSION: MTX suppresses IL-6 synthesis stimulated by various inflammatory agonists in osteoblasts.

3T3 Cells↗
PubMed2004

Chlamydocin-hydroxamic acid analogues as histone deacetylase inhibitors.

Chlamydocin-hydroxamic acid analogues were designed and synthesized as histone deacetylase (HDAC) inhibitors based on the structure and HDAC inhibitory activity of chlamydocin and trichostatin A. Chlamydocin is a cyclic tetrapeptide containing an epoxyketone moiety in the side chain that makes it an irreversible inhibitor of HDAC. We replaced the epoxyketone moiety of chlamydocin with hydroxamic acid to design potent and reversible inhibitors of HDAC. In addition, a number of amino-cycloalkanecarboxylic acids (Acc) are introduced instead of the simple amino-isobutric acid (Aib) for a variety of the series of chlamydocin analogues. The compounds synthesized were tested for HDAC inhibitory activity and the results showed that many of them are potent inhibitors of HDAC. The replacement of Aib residue of chlamydocin with an aromatic amino acid enhances the in vivo and in vitro inhibitory activity. We have carried out circular dichroism and molecular modeling studies on chlamydocin-hydroxamic acid analogue and compared it with the solution structure of chlamydocin.

Animals↗
PubMed2004

Cytoplasmic ubiquitin ligase KPC regulates proteolysis of p27(Kip1) at G1 phase.

The cyclin-dependent kinase inhibitor p27(Kip1) is degraded at the G0-G1 transition of the cell cycle by the ubiquitin-proteasome pathway. Although the nuclear ubiquitin ligase (E3) SCF(Skp2) is implicated in p27(Kip1) degradation, proteolysis of p27(Kip1) at the G0-G1 transition proceeds normally in Skp2(-/-) cells. Moreover, p27(Kip1) is exported from the nucleus to the cytoplasm at G0-G1 (refs 9-11). These data suggest the existence of a Skp2-independent pathway for the degradation of p27(Kip1) at G1 phase. We now describe a previously unidentified E3 complex: KPC (Kip1 ubiquitination-promoting complex), consisting of KPC1 and KPC2. KPC1 contains a RING-finger domain, and KPC2 contains a ubiquitin-like domain and two ubiquitin-associated domains. KPC interacts with and ubiquitinates p27(Kip1) and is localized to the cytoplasm. Overexpression of KPC promoted the degradation of p27(Kip1), whereas a dominant-negative mutant of KPC1 delayed p27(Kip1) degradation. The nuclear export of p27(Kip1) by CRM1 seems to be necessary for KPC-mediated proteolysis. Depletion of KPC1 by RNA interference also inhibited p27(Kip1) degradation. KPC thus probably controls degradation of p27(Kip1) in G1 phase after export of the latter from the nucleus.

Active Transport, Cell Nucleus↗
PubMed2004

Subtype selective substrates for histone deacetylases.

To probe the steric requirements for deacylation, we synthesized lysine-derived small molecule substrates and examined structure-reactivity relationships with various histone deacetylases. Rat liver, human HeLa, and human recombinant class I and II histone deacetylases (HDACs) as well as human recombinant NAD(+)-dependent SIRT1 (class III enzyme) were used in these studies. A benzyloxycarbonyl substituent on the alpha-amino group yielded the highest conversion rates. Replacing the epsilon-acetyl group with larger lipophilic acyl substituents led to a pronounced decrease in conversion by class I and II enzymes; the class III enzyme displayed a greater tolerance. Incubations with recombinant FLAG-tagged human HDACs 1, 3, and 6 showed a distinct subtype selectivity among small molecule substrates. The subtype selectivity of HDAC inhibitors could be predicted with these substrates and an easily obtainable mixture of HDAC subtypes.

Animals↗
PubMed2004

Leptomycin B-induced apoptosis is mediated through caspase activation and down-regulation of Mcl-1 and XIAP expression, but not through the generation of ROS in U937 leukemia cells.

Leptomycin B (LMB), which is originally isolated from Streptomyces, possesses anti-tumor properties in vivo and in vitro. Though it was previously reported that LMB induces cell cycle arrest and p53-mediated apoptosis in certain cancer cells, however, the mechanism by which LMB induces apoptosis remains poorly understood. Here, we investigated the mechanisms of apoptosis induced by LMB in U937 cells. Treatment with LMB concentration-dependently induced cytotoxicity and apoptosis in U937 cells that correlated temporally with activation of caspases and down-regulation of Mcl-1 and XIAP. LMB did not change the expressions of Bcl-2 or Bax. A broad spectrum caspase inhibitor, z-VAD-fmk, blocked caspase-3 activation and elevated the survival in LMB-treated U937 cells, suggesting that caspase-3 activation is critical for LMB-induced apoptosis. Interestingly, Bcl-2 overexpression that blocked cytochrome c release by LMB effectively attenuated the apoptotic response to LMB, suggesting that LMB-induced apoptosis is mediated through the mitochondrial pathway. Antioxidants or antioxidant enzymes had no effects on LMB-induced apoptosis. Data of flow cytometry analysis using 2',7'-dichlorofluorescein-diacetate further revealed no reactive oxygen species (ROS) generation by LMB, indicating that apoptosis induced by LMB is ROS-independent. However, the apoptotic response to LMB was not shown in U937 cells pretreated with the sulfhydryl group-containing antioxidant N-acetylcysteine (NAC). Further analysis suggested that NAC directly binds LMB and abolishes the apoptotic effects of LMB. Collectively, these findings suggest that LMB potently induces apoptosis in U937 cells, and LMB-induced apoptosis in U937 cells is related with cytochrome c release, activation of caspases, and selective down-regulation of Mcl-1 and XIAP.

Antibiotics, Antineoplastic↗
PubMed2004

Current antimicrobial usage for the management of infections in leukemic patients in Japan: results of a survey.

We report the findings of a questionnaire distributed by the Committee of Supportive Care of the Japan Adult Leukemia Study Group to 196 hospitals throughout Japan. For antimicrobial prophylaxis, the oral quinolones are prescribed by 38% of physicians and polymixin B by 31%. For antifungal prophylaxis, amphotericin B is prescribed by 42% of physicians and fluconazole by 41%. Febrile neutropenia is empirically treated with cephalosporin or carbapenem monotherapy by 35% of physicians. Overall, dual therapy (i.e., an aminoglycoside plus a cephalosporin, a carbapenem, or an antipseudomonal penicillin) is prescribed by 50% of physicians. When response to initial empirical therapy does not occur after 3-4 days, 51% of physicians add an antifungal agent; fluconazole is preferred to amphotericin B (prescribed by 66% vs. 28% of physicians). For the treatment of fungemia due to Candida albicans, fluconazole was prescribed by 59% of physicians in cases of stable disease and amphotericin B was prescribed by 57% of physicians in cases of unstable disease. Amphotericin B is selected to treat invasive aspergillosis, but a dose of 0.5-0.7 mg/kg, inadequate for this disease, is prescribed by 44% of physicians. Granulocyte colony-stimulating factor is prescribed to treat patients with acute myelogenous leukemia who have life-threatening infections (27% of physicians) or who have clinically or microbiologically documented infections (26% of physicians).

Anti-Bacterial Agents↗
PubMed2004

Antimicrobial prophylaxis in febrile neutropenia.

Antibiotics generally considered for antibacterial prophylaxis for immunosuppressed patients are trimethoprim-sulfamethoxazole and the quinolones. Trimethoprim-sulfamethoxazole can significantly reduce infections and is highly effective in preventing pneumonia due to Pneumocystis carinii. However, it can cause sulfonamide-related reactions, myelosuppression, oral candidiasis, and development of bacterial resistance, and it lacks activity against Pseudomonas aeruginosa. Quinolones can reduce the occurrence of fever and infections in patients with neutropenia but do not provide adequate coverage against gram-positive bacteria, and inappropriate use can induce resistance among gram-negative organisms. Routine antibacterial prophylaxis is not recommended for patients likely to develop neutropenia. Antifungal prophylaxis is appropriate in settings in which fungal infections are frequent. Fluconazole is recommended for patients who are to undergo hematopoietic stem cell transplantation; it can be considered for elderly patients with acute leukemia who are to receive intensive chemotherapy. Itraconazole can also be used. Prophylaxis with antiviral agents is generally not indicated; however, it should be given to hematopoietic stem cell transplant recipients.

Antibiotic Prophylaxis↗
PubMed2004

Heme regulates gene expression by triggering Crm1-dependent nuclear export of Bach1.

Bach1 is a transcriptional repressor of heme oxygenase-1 and beta-globin genes, both of which are known to be transcriptionally induced by heme. To test the hypothesis that heme regulates the activity of Bach1, we expressed wild type and mutated versions of Bach1 together with or without its heterodimer partner MafK in human 293T and GM02063 cells and examined their subcellular localization. Inhibition of heme synthesis enhanced the nuclear accumulation of Bach1, whereas treating cells with hemin resulted in nuclear exclusion of Bach1. While the cadmium-inducible nuclear export signal (NES) of Bach1 was dispensable for the heme response, a region containing two of the heme-binding motifs was found to be critical for the heme-induced nuclear exclusion. This region functioned as a heme-regulated NES dependent on the exporter Crm1. These results extend the regulatory roles for heme in protein sorting, and suggest that Bach1 transduces metabolic activity into gene expression.

Active Transport, Cell Nucleus↗