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Biomedical subjects

M Miyahara

Publications and source records attributed to M Miyahara.

At least 19 recordsLinked to original sources
PubMed2006

Preparation and catalytic performances of ultralarge-pore TiSBA-15 mesoporous molecular sieves with very high Ti content.

Highly ordered TiSBA-15 mesoporous molecular sieves with different nSi/nTi ratios and tunable pore diameters have been prepared through direct synthesis under various hydrochloric acid concentrations and synthetic temperatures. The structure and the textural parameters of the materials were investigated by powder X-ray diffraction and nitrogen adsorption/desorption measurements. Decrease of the acid concentration and nSi/nTi ratio in the synthetic gel enhanced the amount of Ti incorporation in SBA-15 materials without affecting their structural order and textural parameters. Highly ordered mesoporous TiSBA-15 with a very high Ti content up to a nSi/nTi ratio of 1.9 was prepared for the first time under the optimized synthesis conditions. Control of synthetic temperature resulted in tuning of pore geometries without structural deterioration and Ti content. Ultralarge-pore TiSBA-15 with a pore size of 12.6 nm and a pore volume of 1.3 cm3 g-1 was also synthesized. The nature and the coordination of the Ti atoms in SBA-15 prepared under various synthesis conditions were investigated by UV-vis spectroscopy. It has been found that the Ti atoms are well-dispersed and mostly occupy the tetrahedral coordination under the optimized synthesis conditions. Catalytic performance of the obtained TiSBA-15 materials was also investigated through oxidation of styrene by hydrogen peroxide and tert-butylhydroperoxide as oxidants.

Catalysis↗
PubMed2006

Detection of Lactobacillus gasseri OLL2716 strain administered with yogurt drink in gastric mucus layer in humans.

In animal models and human trials, Lactobacillus gasseri OLL2716 (LG21) strain suppressed Helicobacter pylori colonization in the stomach. The aim of the present study was to clarify whether orally administered LG21 strain can enter the gastric mucus layer. Biopsy samples were taken from the gastric antrum and corpus of two healthy volunteers (H. pylori infected and non-infected) who drank yogurt supplemented with LG21 strains. DNA of LG21 and H. pylori in the mucus layer was detected using the laser-assisted microdissection and non-contact pressure catapulting (LMPC) method and the semi-nested PCR method with primer sets of RNA helicases of superfamily II gene-Insertion sequence for LG21 strain and those of ureA gene for H. pylori. In the volunteer with H. pylori infection, DNA fragments of LG21- and H. pylori-specific regions from both antrum and corpus were amplified, whereas in a non-infected volunteer, only the LG21 DNA from the antrum was amplified. The present study demonstrated that LG21 strains administered through a yogurt drink can enter into the gastric mucus layer. Our novel method may be useful in studying gastric probiotics for H. pylori infection.

Gastric Mucosa↗
PubMed2003

Effects of dental resin metabolites on estrogenic activity in vitro.

Three monomers (Bis-GMA, UDMA, and TEGDMA) and five polymerization initiators (CQ, BPO, DMPT, DMAEMA, and ATU) commonly used in dental composite resins were tested for estrogenic activity using a reporter gene assay (yeast two-hybrid system) in vitro, and compared with bisphenol-A (BPA). Estrogenic activity was indicated by agonist and antagonist activity, with (+S9) and without (-S9) metabolic activation using rat liver cells. No estrogenic agonist activity was seen for each monomer and polymerization initiator in either the -S9 and +S9 tests in the concentration ranges examined in this study. On the other hand, estrogen antagonist activity was found with BPO and DMPT. BPO showed antagonist activity at a concentration of approximately 1800 nM with the -S9 test, but not with the +S9 test. With DMPT, antagonist activity was not seen with the -S9 test, but it was seen at a concentration of approximately 610 nM using the +S9 test. With BPA, the +S9 test indicated antagonist activity at a concentration of approximately 780 nM. The estrogen antagonist activities of DMPT and BPA appeared to be similar. CQ, DMAEMA, ATU, and the three monomers did not show antagonist activity as demonstrated by the -S9 or +S9 tests within the concentration range tested in this study.

Journal Article↗
PubMed2001

A mouse model for adenovirus gene delivery.

The cellular attachment receptor for adenovirus (Ad), Coxsackie adenovirus receptor (CAR), required for delivery of Ad into primary cells, is not present on all cell types, thus restricting Ad-gene delivery systems. To circumvent this constrain, a transgenic mouse has been generated that expresses a truncated human CAR in all tissues analyzed. These mice allowed efficient in vitro infections at low multiplicities into lymphoid, myeloid, and endothelial cells. Furthermore, in vivo administration of Ad-vectors results in infection of macrophages, lymphocytes, and endothelial cells. In addition, tail vein injection resulted in targeting of virus into previously inaccessible areas, such as the lung and the capillaries of the brain. The CAR transgenic mice will be useful for rapid functional genomic analysis in vivo, for testing the efficacy of gene therapy procedures or as a source of easily transducible cells.

Adenoviridae↗
PubMed2001

Detection of Salmonella enteritidis in shell and liquid eggs using enrichment and plating.

Detection methods using various enrichment and plating media and immunoconcentration for Salmonella enteritidis in shell and liquid eggs were evaluated. For liquid egg samples naturally contaminated with S. enteritidis, pre-enrichment in 225 ml of buffered peptone water with cysteine followed by selective enrichment in 10 ml of tetrathionate broth was the superior, resulting in the detection of S. enteritidis in all samples on six of the seven types of selective agar substrate investigated. This enrichment procedure also enabled detection of S. enteritidis in most of artificially inoculated shell egg and pasteurized liquid egg samples.

Animals↗
PubMed2001

Severity of hyperactivity and the comorbidity of hyperactivity with clumsiness in three sample sources: school, support group and hospital.

The aim of this study was to examine whether or not there were any differences in the severity of hyperactivity and the comorbidity of hyperactivity with clumsiness due to the sampling sources of hyperactive children. It was hypothesized that hyperactivity would be more severe and the comorbidity higher in the hospital sample than in the community support group and the school sample. A total of 47 hyperactive children were assessed with the German version of the Conners Teacher Rating Scale (CTRS) and the Movement Assessment Battery for Children (Movement ABC). The hypotheses were not supported by the results. Although the school sample demonstrated the least prevalence rate of comorbid clumsiness, their conduct problems were rated higher than were the hospital and the support group samples. The possible difference in teachers' perception was discussed in terms of their understanding and communication with parents and professionals. The need to determine the effect of inattention on manual performance is addressed with a research strategy.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

Requirement of interaction of nectin-1alpha/HveC with afadin for efficient cell-cell spread of herpes simplex virus type 1.

We recently found a novel cell-cell adhesion system at cadherin-based adherens junctions (AJs), consisting at least of nectin, a Ca(2+)-independent homophilic immunoglobulin-like adhesion molecule, and afadin, an actin filament-binding protein that connects nectin to the actin cytoskeleton. Nectin is associated with cadherin through afadin and alpha-catenin. The cadherin-catenin system increases the concentration of nectin at AJs in an afadin-dependent manner. Nectin constitutes a family consisting of three members: nectin-1, -2, and -3. Nectin-1 serves as an entry and cell-cell spread mediator of herpes simplex virus type 1 (HSV-1). We studied here a role of the interaction of nectin-1alpha with afadin in entry and/or cell-cell spread of HSV-1. By the use of cadherin-deficient L cells overexpressing the full length of nectin-1alpha capable of interacting with afadin and L cells overexpressing a truncated form of nectin-1alpha incapable of interacting with afadin, we found that the interaction of nectin-1alpha with afadin increased the efficiency of cell-cell spread, but not entry, of HSV-1. This interaction did not affect the binding to nectin-1alpha of glycoprotein D, a viral component mediating entry of HSV-1 into host cells. Furthermore, the cadherin-catenin system increased the efficiency of cell-cell spread of HSV-1, although it also increased the efficiency of entry of HSV-1. It is likely that efficient cell-cell spread of HSV-1 is caused by afadin-dependent concentrated localization of nectin-1alpha at cadherin-based AJs.

Amino Acid Sequence↗
PubMed2001

Local nonpermissive and oriented permissive cues guide vestibular axons to the cerebellum.

Information that originates from peripheral sensory organs is conveyed by axons of cephalic sensory cranial ganglia connecting the sensory organs to appropriate central targets in the brain. Thus, the establishment of correct axonal projections by sensory afferents is one of the most important issues in neural development. Previously, we examined the development of the vestibular nerve that originates from the VIIIth ganglion using a flat whole-mount preparation of the rat hindbrain and developed an in vitro, culture preparation that can recapitulate vestibular nerve development (Tashiro, Y., Endo, T., Shirasaki, R., Miyahara, M., Heizmann, C. W. and Murakami, F. (2000) J. Comp. Neurol. 417, 491-500). Both in vivo and in vitro, the ascending branch of the VIIIth ganglion projecting to the cerebellum reaches the base of the cerebellar primordium and starts to splay out towards the rhombic lip, apparently avoiding the ventral metencephalon. We now examine the nature of cues that guide vestibulocerebellar axons by applying various manipulations to the flat whole-mount in vitro preparation. Our observations suggest that local nonpermissive cues and oriented cues play a pivotal role in the guidance of vestibular axons to their central target.

Afferent Pathways↗
PubMed2000

Purification, identification, and cDNA cloning of Jun a 2, the second major allergen of mountain cedar pollen.

The second major allergen of Juniperus ashei (mountain cedar) pollen, Jun a 2, has been purified and its cDNA cloned. The purified protein has a molecular mass of 43 kDa and its N-terminal 9-residue amino acid sequence is highly homologous to those of Cry j 2 and Cha o 2, the second major allergen of Cryptomeria japonica and Chamaecyparis obtusa pollen, respectively. cDNA clones encoding Jun a 2 were isolated after PCR based amplification, and their nucleotide sequences were determined. The cDNA contains an open reading frame of 507 amino acid residues, and encodes a putative 54-residue signal sequence and a 453-residue intermediate, which releases a C-terminal fragment upon maturation. Three possible N-linked glycosylation sites and 20 cystein-residues are found in the deduced amino acid sequence. The amino acid sequence of Jun a 2 shows 70.7 and 82.0% identity with those of Cry j 2 and Cha o 2, respectively. Immunological observations that IgE antibodies in sera of Japanese pollinosis patients bind not only to Cry j 2 and Cha o 2 but also to Jun a 2 strongly suggest that Jun a 2 is an allergen of mountain cedar pollen, and that allergenic epitopes of these three allergens are similar.

Allergens↗
PubMed2000

Two actions of frabin: direct activation of Cdc42 and indirect activation of Rac.

Frabin is an actin filament-binding protein which shows GDP/GTP exchange activity specific for Cdc42 small G protein and induces filopodium-like microspike formation and c-Jun N-terminal kinase (JNK) activation presumably through the activation of Cdc42. Frabin has one actin filament-binding (FAB) domain, one Dbl homology (DH) domain, first pleckstrin homology (PH) domain adjacent to the DH domain, one cysteine-rich FYVE domain, and second PH domain from the N-terminus to the C-terminus in this order. Different domains of frabin are involved in the microspike formation and the JNK activation, and the association of frabin with the actin cytoskeleton through the FAB domain is necessary for the microspike formation, but not for the JNK activation. We have found here that frabin induces the formation of not only filopodium-like microspikes but also lamellipodium-like structures in NIH3T3 and L fibroblasts. We have analysed the mechanism of frabin in these two actions and found that frabin induces filopodium-like microspike formation through the direct activation of Cdc42 and lamellipodium-like structure formation through the Cdc42-independent indirect activation of Rac small G protein. The FAB domain of frabin in addition to the DH domain and the first PH domain is necessary for the filopodium-like microspike formation, but not for the lamellipodium-like structure formation. The FYVE domain and the second PH domain in addition to the DH domain and the first PH domain are necessary for the lamellipodium-like structure formation. We show here these two actions of frabin in the regulation of cell morphology.

3T3 Cells↗
PubMed2000

Nectin-3, a new member of immunoglobulin-like cell adhesion molecules that shows homophilic and heterophilic cell-cell adhesion activities.

We have isolated a novel cell-cell adhesion system localized at cadherin-based adherens junctions (AJs). This system consists of at least nectin, a Ca(2+)-independent immunoglobulin-like adhesion molecule, and afadin, an actin filament-binding protein, that connects nectin to the actin cytoskeleton. Nectin constitutes a family consisting of two members, nectin-1 and -2. We have isolated here a third member of the nectin family and named it nectin-3. Nectin-3 has three splicing variants, nectin-3alpha (biggest), -3beta (middle), and -3gamma (smallest). Like nectin-1 and -2, nectin-3alpha consists of three extracellular immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic region with the C-terminal consensus motif for binding to the PDZ domain. Nectin-3alpha formed a cis-homo-dimer and showed Ca(2+)-independent trans-homo-interaction to cause homophilic cell-cell adhesion. Nectin-3alpha furthermore showed trans-hetero-interaction with nectin-1 or -2 but did not form a cis-hetero-dimer with nectin-1 or -2. Nectin-1 did not show trans-hetero-interaction with nectin-2. The affinity of trans-hetero-interaction of nectin-3alpha with nectin-1 or -2 was higher than that of trans-homo-interaction of nectin-1, -2, or -3alpha. Nectin-2 and -3 were ubiquitously expressed, whereas nectin-1 was abundantly expressed in brain. Nectin-3alpha was colocalized with nectin-2 at cadherin-based AJs and interacted with afadin. These results indicate that the nectin family consists of at least three members, nectin-1, -2, and -3, all of which show homophilic and heterophilic cell-cell adhesion activities and are localized at cadherin-based AJs.

Alternative Splicing↗
PubMed2000

Afferents of cranial sensory ganglia pathfind to their target independent of the site of entry into the hindbrain.

In vertebrates, sensory neurons interconnect a variety of peripheral tissues and central targets, conveying sensory information from different types of sensory receptors to appropriate second-order neurons in the central nervous system (CNS). To explore the possibility that the different rhombomere environments where sensory neurons enter into the hindbrain affect the pathfinding capability of growth cones, we studied the development of the VIIIth ganglion afferent both in vivo and in vitro. We focused on the vestibular nerve because it is the only cranial nerve projecting to the cerebellum, allowing for ready identification from its pattern of projection. Embryonic rat brain was cut along the dorsal midline and, with the VIIIth and Vth ganglia still attached, flat mounted and visualized with antibodies specific for sensory ganglia. Axons reached the cerebellar primordium at embryonic day (E) 13, then splayed out towards the edges of the rhombic lip of rostral hindbrain. In vitro, the VIIIth ganglion showed development similar to that in vivo and innervated the cerebellum, an appropriate target, indicating that mechanisms for axon guidance and target recognition are preserved in vitro. When the VIIIth ganglion was transplanted to the position of the Vth ganglion, axons from the transplanted ganglion entered the cerebellar primordium with a trajectory characteristic of the VIIIth nerve. These results indicate that the central projection pattern of the VIIIth nerve is not affected by the environment of nerve entry into the brainstem, suggesting that axons of sensory cranial ganglion intrinsically possess the capacity to find their target correctly.

Afferent Pathways↗
PubMed2000

Interaction of nectin with afadin is necessary for its clustering at cell-cell contact sites but not for its cis dimerization or trans interaction.

We have recently found a novel functional unit of cell-cell adhesion at cadherin-based adherens junctions, consisting of at least nectin, a homophilic cell adhesion molecule, and afadin, an actin filament-binding protein, which connects nectin to the actin cytoskeleton. Here we studied a mechanism of cell-cell adhesion of the nectin-afadin system by use of a cadherin-deficient L cell line stably expressing the intact form of mouse nectin-2alpha, a truncated form of nectin-2alpha incapable of interacting with afadin (nectin-2alpha-DeltaC), or a point-mutated form of nectin-2alpha capable of interacting with afadin and a cadherin-expressing EL cell line, which transiently expressed the point-mutated form of nectin-2alpha. We found that the interaction of nectin-2alpha with afadin was necessary for their clustering at cell-cell contact sites. However, nectin-2alpha-DeltaC showed cis dimerization and trans interaction, both of which did not require the interaction of nectin-2alpha with afadin. We have previously shown in EL cells that the interaction of nectin-1 with afadin is necessary for its recruitment to adherens junctions. We found that the trans interaction of nectin-2alpha was furthermore necessary for this recruitment. On the basis of these observations, we propose a model for the mechanism of cell-cell adhesion of nectin and roles of afadin in this mechanism.

Animals↗
PubMed2000

B-cell lymphoma-associated hemophagocytic syndrome: clinicopathological characteristics.

Seven patients with peripheral B-cell lymphoma associated with hemophagocytic syndrome are reported. In all cases, the histologic subtype was diffuse large B-cell lymphoma. Hemophagocytic features were noted in the bone marrow with lymphomatous infiltration. Hemophagocytic syndrome occurred with presentation of the lymphoma and was characterized by high fever, cytopenias, and elevated levels of lactate dehydrogenase, ferritin, C-reactive protein, and cytokines [interferon gamma, macrophage colony-stimulating factor, soluble interleukin (sIL)-2R, and IL-6] without evidence of infection. The phenotypes of lymphomas were suspected CD19+, CD20+, S-Ig+, CD10-, and coexpression of CD5 in some cases. Flow cytometric analysis showed a low CD4/CD8 ratio in peripheral blood and bone marrow. We suggest that the pathogenesis of hemophagocytic syndrome is hypercytokinemia induced by a proliferation of reactive CD8+ T cells. Previous reports of B-cell lymphoma with hemophagocytic syndrome demonstrated similar clinical manifestations and poor prognoses. The invasion patterns of these diffuse large B-cell lymphomas with hemophagocytosis may be classified into three groups: microscopic lymph-node involvement type, gross lymph-node involvement type, and splenic lymphoma type. Although hemophagocytic syndromes have been reported to be associated with T-cell lymphomas, our results indicate an association with diffuse large B-cell lymphoma.

Aged↗
PubMed2000

Somnolence syndrome in a child following 1200-cGy total body irradiation in an unrelated bone marrow transplantation.

Neurological complications may occur following intensive chemotherapy and hematopoietic cell transplantation. Postirradiation somnolence syndrome has been observed in children with acute lymphoblastic leukemia who received central nervous system preventive therapy with 1800-2400 cGy cranial irradiation. The authors report a 16-year-old boy with chronic myelogenous leukemia in chronic phase, who developed symptoms compatible with the somnolence syndrome (SS) 6 weeks following HLA-matched unrelated bone marrow transplantation (BMT). The preparative regimen consisted of 1200 cGy total body irradiation (TBI), cytosine arabinoside and cyclophosphamide. The patient developed lethargy and low-grade fever, with intermittent rhythmical delta activity in electroencephalograph. He recovered spontaneously without specific therapy 3 weeks after developing symptoms. This is the first report describing that as low as 1200 cGy TBI can induce SS in a child. After allogeneic BMT, some patients develop neurological symptoms. The authors suggest that somnolence syndrome should be included in differential diagnosis in these patients.

Adolescent↗
PubMed2000

Loss of O157 O antigenicity of verotoxin-producing Escherichia coli O157:H7 surviving under starvation conditions.

Verotoxin (VT)-producing Escherichia coli O157:H7 was culturable on agar media after being left in water for 21 months. However, there were a number of colonies which had lost O157 O antigenicity. These colonies produced VTs, which are pathogenic to humans. These observations suggest that the immunologic methods based on O157 O antigenicity are unable to detect and isolate VT-producing E. coli in foods and other environments if the organism has been under starvation conditions for a long period.

Animals↗
PubMed2000

Capability for identification of gamma-irradiated bovine liver by new high sensitivity comet assay.

DNA in food will sustain damage by gamma radiation. The detection capability of the high sensitivity comet assay was studied using fluorescence-microscopy. Beef liver was irradiated at a range of 1 Gy to 8 kGy. Single cells were obtained from the irradiated liver, then analyzed by agaros-gel electrophoresis. The pH of the buffer for electrophoresis was pH 13, which is generally utilized for sensitive detection of DNA damage. The pattern formed by DNA was visualized by staining with ethidium bromide. The resulting comets were evaluated with a scale we developed, and Influence Scores were calculated based on the Tice method. It is possible to detect irradiation damage to beef liver at 10 Gy. Together with Influence Score, histogram of comet type is used for detection of irradiation. We elucidated those histograms were useful for distinguishing damage caused by irradiation from that of others. DNA damage can be caused not only by irradiation, but also by the other treatments. Therefore, the respective influences of freezing, preservation, irradiating temperature, atmosphere of irradiation, cooking, and homogenizing devices were also examined. This new comet assay will be a useful method of detecting DNA damage to identify irradiated foods.

Animals↗