Biomedical subjects

Y Sato

Publications and source records attributed to Y Sato.

At least 397 records · Page 22Linked to original sources

PubMed2000

Overexpression of rice OSH genes induces ectopic shoots on leaf sheaths of transgenic rice plants.

Five rice homeobox (OSH) genes were overexpressed under the control of the cauliflower mosaic virus 35S promoter or the rice actin gene promoter in transgenic rice plants. Almost all of the transgenic plants showed abnormal phenotypes, which could be classified into three types according to their severity. Plants with the most severe phenotype formed only green organs, with many shoot apices on their adaxial sides. Plants with an intermediate phenotype formed bladeless leaves with normally developed leaf sheaths. Plants with a mild phenotype formed normal leaf sheaths and blades, but lacked ligules and showed diffusion of the blade-sheath boundary. The leaf structure of this phenotype was similar to that of dominant maize mutants, such as Kn1, Rs1, Lg3, and Lg4. Based on these phenotypes, we suggest that ectopic expression of the rice OSH genes interferes with the development of leaf blades and maintains leaves in less differentiated states. These results are discussed in relation to the leaf maturation schedule hypothesis (M. Freeling et al., 1992, BioEssays 14, 227-236).

Actins↗

PubMed2000

Influence of immobilization upon calcium metabolism in the week following hemiplegic stroke.

Hip fractures on the paretic side are a serious post-stroke complication and may result from disuse hemiosteopenia, hypovitaminosis D, and an increasing risk of falls. To evaluate short-term immobilization effects, we assessed calcium metabolism in 89 patients 1 week after the hemiplegic stroke and in 36 controls. Patient activity was rated using the Barthel index (BI). Sera from stroke patients and control subjects were assayed for ionized calcium, parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OHD), 1, 25-dihydroxyvitamin D (1,25-(OH)(2)D), bone Gla protein (BGP; a bone formation marker) and pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker). Patients' serum concentrations of ionized calcium and ICTP were higher than in controls and correlated negatively with BI; their BGP concentrations were low, correlating positively with BI. Concentrations of serum 25-OHD, 1,25-(OH)(2)D, and PTH also were low; serum 25-OHD was at a deficient level (<10 ng/ml) in nine patients (10%), an insufficient level (10-20 ng/ml) in 56 (63%), and a sufficient level (>20 ng/ml) in only 24 (27%). PTH correlated negatively with calcium and 1,25-(OH)(2)D. Hypovitaminosis D is common in acute stroke patients. Immobilization from acute hemiplegia can increase bone resorption and serum calcium, and inhibit PTH secretion and 1,25-(OH)(2)D production to add to the effects of hypovitaminosis D.

Aged↗

PubMed2000

New amphiphilic aminosaccharide derivatives as chiral selectors in capillary electrophoresis.

Two amphiphilic aminosaccharide derivatives were investigated as chiral selector additives in capillary electrophoresis. Each substance has a glucosamine backbone carrying three hydrocarbon chains as the hydrophobic region and three carboxylic groups as the hydrophilic region, which is an artificial biologically active compound. Using each compound as a chiral selector, the optical resolution of dansylated amino acids or new quinolone antibacterial agents (NQs) was observed. Increasing the concentration of the chiral selector or the ionic strength of running solution led to successful optical resolution. In consideration of the chemical structure of each selector and the migration behavior of the enantiomers, the resolution seemed to be based on micellar electrokinetic chromatography mode. Both selectors differed in their enantioselectivity for dansylated amino acids or NQs although the chemical structures were similar.

Amines↗

PubMed2000

Expression and localization of human herpesvirus 8-encoded proteins in primary effusion lymphoma, Kaposi's sarcoma, and multicentric Castleman's disease.

To investigate the expression of human herpesvirus 8 (HHV8)-encoded proteins in the cells of primary effusion lymphoma (PEL), Kaposi's sarcoma (KS) and multicentric Castleman's disease (MCD), nine rabbit polyclonal antibodies to K2, ORF26, K8, K8.1, K10, K11, ORF59, ORF65, and ORF73 were developed. Western blot analysis in PEL cell lines (TY-1 and BCBL-1) revealed that the expression of these proteins, except ORF73 (LANA), was induced by tetradecanoylphorbol acetate (TPA) treatment, indicating that these proteins are lytic proteins. Immunofluorescence assay in primary PEL cells derived from pericardial effusion and PEL cell lines with and without TPA treatment revealed that primary PEL cells exhibited the same expression pattern as noninduced PEL cell lines, and the treatment changed localization of K8, ORF59, and ORF65 proteins. Immunohistochemistry revealed that 90% of KS spindle cells expressed the ORF73 protein, whereas a small population of KS cells expressed K8, K10, K11, ORF59, and ORF65 proteins. In MCD, ORF73, ORF59, K8, K2, and K10 proteins were expressed in the cells at mantle zone of the follicle. These data indicate that KS and PEL cells expressed predominantly latent proteins, whereas MCD expressed both latent and lytic proteins, suggesting that HHV8 plays a different role in the pathogenesis of HHV8-associated diseases.

Animals↗

PubMed2000

Calcitonin gene-related peptide produces skeletal muscle vasodilation following antidromic stimulation of unmyelinated afferents in the dorsal root in rats.

In anesthetized rats, the contribution of calcitonin gene-related peptide (CGRP) to antidromic vasodilation of skeletal muscle blood flow (MBF) following electrical stimulation of muscle afferent was investigated by measuring biceps femoris MBF using laser Doppler flowmetry. Repetitive antidromic electrical stimulation of unmyelinated C fibers in ipsilateral dorsal roots at the 3rd-5th lumbar segments for 30 s caused an increase in MBF for 3-15 min (mean 4.5 min) without significant change in systemic arterial blood pressure. The increase in skeletal MBF started about 10 s after the onset of stimulation, and peaked at approximately 130% of the control value at about 30 s after the end of the 30 s period of stimulation. The MBF response was totally abolished by topical application of hCGRP (8-37), a CGRP receptor antagonist. It is concluded that antidromic vasodilation in skeletal muscles following stimulation of unmyelinated C afferents in dorsal roots is independent of systemic blood pressure and is mediated essentially by CGRP. It is suggested that this CGRP-related antidromic vasodilation may be important in the clinical improvement of skeletal MBF produced by physical therapy, e.g. acupuncture.

Afferent Pathways↗

PubMed2000

Microsequencing of glycans using 2-aminobenzamide and MALDI-TOF mass spectrometry: occurrence of unique linkage-dependent fragmentation.

2-Aminobenzamide-derivatized oligosaccharides were separated by three lectin column chromatographies and then subjected to matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for structural characterization of the carbohydrates. The combination of sequential exoglycosidase digestion and MALDI-TOF MS greatly facilitates the monosaccharide sequencing and is more feasible than size-exclusion column chromatography in terms of the time consumed and the laboriousness of the procedure. By this strategy, microsequencing of 2-3 pmol of oligosaccharide derivatives could be achieved. Furthermore, spectra obtained by the post source decay (PSD) mode provide excellent sequence information. The relative intensities of metastable ions due to fragmentation at glycosidic linkages were different among linkage isomers of particular oligosaccharides. These results demonstrate that PSD analysis possesses significant potential for the estimation of glycosidic linkage in carbohydrate structures.

Carbohydrate Sequence↗

PubMed2000

A new ETV6/TEL partner gene, ARG (ABL-related gene or ABL2), identified in an AML-M3 cell line with a t(1;12)(q25;p13) translocation.

The ETV6/TEL gene has been reported to fuse to PDGFRbetab MDS1/EVI1, BTL, ACS2, STL, JAK2, ABL, CDX2, TRKC, AML1, and MN1. Among them, PDGFRbeta, ABL, JAK2, and TRKC are tyrosine kinases (TK). We identified a novel ETV6 partner gene, ARG (ABL-related gene or ABL2), another TK gene in a cell line established from a patient with acute myelogenous leukemia (AML-M3) with a t(15;17)(q22;q11.2) and a t(1;12)(q25;p13), which has the remarkable feature to differentiate to mature eosinophils in culture with all-trans retinoic acid and cytokines. The ETV6/ARG transcripts consisted of exon 1 to 5 of ETV6 and the 3' portion of ARG starting from exon 1B or exon 2, resulting in an open reading frame for a fusion protein consisting of the entire PNT oligomerization domain of ETV6 and all of the functional domains of ARG including the TK domain. This is the same protein structure as identified in the other ETV6 TK fusion proteins. The reciprocal ARG/ETV6 transcript was not expressed, and the normal ETV6 allele was not deleted or rearranged. Although the ABL is known to be involved in various human malignancies, ARG has not been involved in human malignancies despite its high homology to ABL. Thus, this is the first report showing involvement of ARG in human leukemia. The ETV6/ARG protein may be involved in the unique differentiation capacity of this cell line. (Blood. 2000;95:2126-2131)

Adaptor Proteins, Signal Transducing↗

PubMed2000

Alterations with age of the neurons expressing P(0) in the rat spinal cord.

In mammals, P(0) expression is thought to be restricted to the peripheral nervous system (PNS), whereas in some other vertebrates it is expressed not only in the PNS but also in the central nervous system (CNS). Previously we reported that P(0) is expressed in the rat spinal cord and that its glycosylation state changes with age. In this report, we determine, by immunohistochemical and immunocytochemical analyses, that the neurons in the spinal cord express P(0). Furthermore, our data show that the number of neurons expressing P(0) decreases and their sizes become smaller with age. Thus, the results emphasize the importance of neurons expressing P(0) in the spinal cord in the formation and maintenance of the neural network.

Aging↗

PubMed2000

Non-ionic detergent Tween 80 modulates VP-16 resistance in classical multidrug resistant K562 cells via enhancement of VP-16 influx.

The non-ionic detergent Tween 80, which is used as a solvent for lipophilic drugs such as VP-16 and Taxotere, was found to reverse VP-16 resistance of the P-glycoprotein-associated multidrug resistance phenotype via increasing VP-16 influx. In adriamycin-resistant human chronic myelogenous leukemia K562 cells (K562/ADM), which overexpress mdr1 mRNA, the accumulation of VP-16 was only about 10% that in wild-type K562 cells. Tween 80 enhanced VP-16 accumulation in K562/ADM cells but did not influence VP-16 accumulation in parental K562 cells. VP-16 efflux was rapid and similar in both sensitive and resistant cell lines and was not blocked by Tween 80 or verapamil. Under glucose-free conditions, VP-16 accumulation in K562/ADM cells was only half of that in K562 cells. Tween 80 increased VP-16 accumulation in K562/ADM cells in glucose-free medium. In growth inhibition assay, Tween 80 reversed K562/ADM sensitivity to VP-16 without cell damage. Taken together, Tween 80 reverses VP-16 sensitivity in multidrug-resistant K562 cells by increasing influx, which is considered to be the primary mechanism of VP-16 resistance in K562/ADM cells.

Antineoplastic Agents, Phytogenic↗

PubMed2000

Synthesis of eight-membered ring compounds using enyne metathesis

[reaction: see text] A novel procedure for synthesizing eight-membered ring compounds was developed using ruthenium-catalyzed enyne metathesis. When a CH2Cl2 solution of enyne connected with catechol, o-amino phenol, or o-phenylenediamine was stirred in the presence of benzylidene ruthenium carbene complex (10 mol %) at room temperature overnight, an eight-membered ring compound was obtained in high yield. In a similar manner, monocyclic 1,4-diaza- or 1-oxa-4-azacyclooctene derivative was obtained in high yield.

Journal Article↗

PubMed2000

Lymphatic lipid transport is not impaired in ageing rat intestine.

Lymphatic lipid transport in the intestine of adult and ageing rats was compared. Adult (8-10 months old) and old (24-26 months old) male Wistar rats were cannulated into the mesenteric lymph under ethrane anesthesia. On the following day, lipid emulsion containing 35.4 mg/h of olive oil was infused intraduodenally for 7 h and lymph collected hourly was assayed for triglyceride and apolipoprotein A-IV (apo A-IV). The results showed there was no difference in lymphatic lipid and apo A-IV transport between adult and old rats. Since apo A-IV synthesis in the enterocytes is linked to the intracellular assembly of lipoprotein, it is likely that in addition to lymphatic transport, production of chylomicrons is not impaired in ageing rats.

Aging↗

PubMed2000

Distinct prognostic values of p53 mutations and loss of estrogen receptor and their cumulative effect in primary breast cancers.

A total of 76 primary breast cancers were screened for p53 mutations using the yeast p53 functional assay, and the mutations were determined by DNA sequencing. Clonal mutations of p53 were detected in 30 tumors (39%). Immunohistochemical staining for nuclear p53 accumulation performed on the yeast assay-positive cases clearly differentiated missense mutations in the DNA binding domain (contact mutant; 17 cases) as positive stain and nonsense-type mutations or missense mutations that may affect 3D-structure of p53 protein (structural mutant; 13 cases) as negative stain. Enzyme immunoassay revealed loss of estrogen receptor in 36 tumors (50%). Prognostic values of p53 mutation and loss of estrogen receptor were evaluated after a median follow-up period of 44 months. p53 mutations were associated with a short overall survival (log rank test, p = 0.0319), whereas it was not related to disease-free (recurrence-free) survival. Contact mutants were associated with slightly shorter survival compared with structural mutants. Inversely, loss of estrogen receptor was associated with early recurrence (p = 0.0461) but not with short overall survival. The patients with tumors harboring both p53 mutation and loss of estrogen receptor had the poorest outcome (p = 0.0019 and 0.0075 for overall and disease-free survivals, respectively), suggesting independent and additive effects of the 2 factors. The independent role of the 2 factors was confirmed by a multivariate analysis using the Cox proportional hazard model stratified according to clinical tumor stages. Although preliminary, due to the small number of patients studied and the relatively short follow-up time, our results suggest that p53 mutations and loss of estrogen receptor cooperatively affect the prognosis of primary breast cancer patients.

Adult↗

PubMed2000

Pulmonary hypertension associated with pulmonary occlusive vasculopathy after allogeneic bone marrow transplantation.

BACKGROUND: Pulmonary vasculature abnormalities, including pulmonary veno-occlusive disease, have been demonstrated in marrow allograft recipients. However, it is often difficult to make a correct diagnosis of pulmonary lesions. METHODS: An open lung biopsy was performed on a patient who developed severe pulmonary hypertension after bone marrow transplantation for T-cell lymphoma. RESULTS: An open lung biopsy specimen demonstrated pulmonary arterial occlusion due to intimal fibrosis and veno-occlusion. The most striking alteration was partial to complete occlusion of the small arteries by fibrous proliferation of the intima. CONCLUSION: High-dose preparative chemotherapy and radiation before transplantation are thought to have contributed to the development of vasculopathy in this patient, because arterial occlusion by intimal fibrosis and atypical veno-occlusion are often associated with lung injury due to chemoradiation. An open lung biopsy is essential for diagnosing pulmonary vascular disease presenting signs compatible with posttransplantation pulmonary hypertension.

Adult↗

PubMed2000

Injection of plasmid DNA into the gastric mucosa induces mucosal and systemic immunity.

Nearly all mucosal surfaces participate in a common mucosal immune system, and application of an antigen to one mucosal surface elicits local as well as distant mucosal immune responses. However, whether the gastric mucosa is a part of this network has not been examined directly. We show here that the injection of plasmid DNA encoding beta-galactosidase into the gastric wall caused transfection of gastric mucosal epithelial cells, induced systemic and mucosal antibody responses at both local (digestive tract) and distant (genital and respiratory tracts) sites, and induced cytotoxic T lymphocyte responses in the spleen and the mesenteric and iliac lymph nodes.

Animals↗

PubMed2000

Indispensable role of the transcription factor PEBP2/CBF in angiogenic activity of a murine endothelial cell MSS31.

Mice lacking the AML1/PEBP2alphaB/CBFa2 gene or PEBP2beta/CBFb gene exhibit a defect in definitive hematopoiesis and die in utero because of hemorrhage in the central nervous system. Hematopoiesis in the embryo is considered to be tightly associated with vascular development. Here we examined whether PEBP2/CBF plays any role in angiogenesis besides that in definitive hematopoiesis. We found that AML1/PEBP2alphaB/CBFa2, PEBP2alphaA/CBFa1, and PEBP2beta/CBFb were expressed in a murine endothelial cell line MSS31. The expression of these molecules as well as the DNA binding activity of PEBP2/CBF were augmented by angiogenic growth factors such as bFGF and VEGF. Moreover, the expression of PEBP2 alpha/CBFa protein in endothelial cells was confirmed at the site of angiogenesis in vivo. To further clarify the role of PEBP2/CBF in angiogenesis, we established permanent transfectants of PEBP2 beta-MYH11 gene, one that interacts with the runt domain of the alpha subunit and deregulates PEBP2/CBF in a dominant interfering manner. Proliferation, migration, and tube formation of the PEBP2 beta-MYH11 transfectants were significantly reduced in comparison with those activities of the mock transfectants. These results suggest that transcription factor PEBP2/CBF plays an important role in angiogenesis.

Animals↗

PubMed2000

Involvement of a phosphatidylinositol 3-kinase-p38 mitogen activated protein kinase pathway in antigen-induced IL-4 production in mast cells.

We studied the involvement of phosphatidylinositol 3-kinase (PI3-kinase) in the antigen-induced IL-4 production in a rat mast cell line, RBL-2H3. The stimulation of IgE-sensitized RBL-2H3 cells by the antigen resulted in increased IL-4 mRNA levels followed by increased IL-4 production. Wortmannin and LY294002, PI3-kinase inhibitors, partially reduced both the antigen-induced increases in the IL-4 mRNA levels and IL-4 production in a concentration-dependent manner. Extracellular signal-regulated kinase, p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK), which belong to the MAPK family, were activated by the antigen stimulation, and the activation of p38 MAPK in addition to JNK was suppressed markedly by wortmannin. The phosphorylation of endogenous activating transcription factor-2, a substrate of p38 MAPK, was also inhibited by wortmannin. The specific p38 MAPK inhibitor SB203580 partially inhibited the antigen-induced IL-4 production at mRNA levels, but the MEK-1 inhibitor PD98059 enhanced it. These findings suggest that the activation of PI3-kinase and p38 MAPK is partially responsible for the antigen-induced IL-4 production in RBL-2H3 cells.

Activating Transcription Factor 2↗

PubMed2000

Nd:YAG laser irradiation of the human dental pulp: implications as a predictor of pulp hemodynamics.

BACKGROUND AND OBJECTIVE: The aim of study this was to evaluate in vivo the pulpal blood flow rate, pulpal responsiveness, systemic blood pressure, and pulse rate during Nd:YAG laser irradiation of an isolated tooth. STUDY DESIGN/MATERIALS AND METHODS: Thirteen volunteers from the Tsurumi Dental University faculty participated in this study after giving their consent to the Nd:YAG laser irradiation test protocol. Gingivobuccal areas adjacent to mandibular canines were used for clinical evaluation. Each area was coated with India ink and treated with a Nd:YAG laser for 30 sec at 120-mJ pulses at 10 pulses/sec. Pulpal blood flow was measured by a laser Doppler flowmeter during Nd:YAG laser irradiation of the tooth. All pulp responses were measured by an electric pulp tester before and after Nd:YAG laser irradiation. In addition, the systemic blood pressure and pulse rate were monitored throughout the laser irradiation procedure. RESULTS: For all subjects involved in this study, the pulpal blood flow rate increased during laser irradiation. Threshold values of the electric pulp tests increased in six cases and decreased in six cases. One case showed no change. After 1 month, the threshold values for each subject had returned to previously recorded values. Neither systemic blood pressure nor pulse rate was affected during Nd:YAG laser irradiation. Pulpal blood flow was strongly influenced immediately after Nd:YAG laser irradiation, seen as an increase in the flow rate. CONCLUSION: The results of this study suggest that effects of the Nd:YAG laser irradiation are similar to those of low power laser for the improvement of local blood flow.

Adult↗

PubMed2000

Morphogenetic behavior of periodontium on inorganic implant materials: an experimental study of canines.

Periodontal ligament derived cells have the potential to regenerate all the components of the periodontium on the surface of inorganic implants, as well as on dentin. This suggests the hypothesis that the nature of the material affects the migration, proliferation, and differentiation of the progenitor cells for periodontium formation. To clarify this hypothesis, we evaluated the material-specific morphogenetic potential of periodontium-derived cells using an animal model for inducing cell migration from the functioning periodontium onto bioactive (hydroxyapatite, HA) and bioinert (titanium alloy, TA) material. Histologically, total periodontium including calcified cementum-like tissue only formed on HA and not on TA. Morphometrically, however, the length of fibrous connective tissue formed on HA was the same as on TA. This suggests that the bioactivity of the material does not affect the migration of periodontium-derived cells but strongly influences cell differentiation.

Animals↗