Biomedical subjects

Y Matsuda

Publications and source records attributed to Y Matsuda.

At least 127 records · Page 7Linked to original sources

PubMed2001

Scleral plug of biodegradable polymers containing ganciclovir for experimental cytomegalovirus retinitis.

PURPOSE: To evaluate the efficacy of a biodegradable scleral plug containing ganciclovir (GCV) in a rabbit model of human cytomegalovirus (HCMV) retinitis. METHODS: To develop a rabbit model for HCMV retinitis, HCMV solution was injected once into the vitreous cavity of pigmented rabbits. The treated animals were divided into three groups: group A received no treatment, group B was treated once with GCV solution, and group C was treated with a scleral plug containing GCV. Rabbits in group B received an intravitreal injection of GCV solution 1 week after HCMV inoculation. In group C, the scleral plug containing GCV was implanted in the vitreous of the rabbits 1 week after HCMV inoculation. Ophthalmoscopically, vitreoretinal findings in each group were graded from 0+ to 4+ every week for 4 weeks after HCMV injection. RESULTS: Eyes of group A rabbits showed whitish retinal exudates and vitreous opacities 3 days after HCMV inoculation. These materials increased gradually until 3 weeks after HCMV inoculation. Scores for vitreoretinal lesions were significantly lower in eyes of group B rabbits compared with those of group A at 1 week after GCV injection (P < 0.05). However, vitreoretinal inflammation in eyes of group B rabbits increased again thereafter, and no significant difference in inflammation between groups A and B was found 2 weeks after GCV injection. In eyes of group C, scores for vitreoretinal lesions were significantly lower compared with those in both group A and group B at 3 weeks after HCMV inoculation (P < 0.01). CONCLUSIONS: The results demonstrated that sustained release of GCV into the vitreous cavity with biodegradable scleral plugs was effective for the treatment of experimentally induced HCMV retinitis in rabbits.

Absorbable Implants↗

PubMed2001

[A rabbit model for human cytomegalovirus retinitis].

PURPOSE: To develop a rabbit model for human cytomegalovirus(HCMV) retinitis. METHODS: 0.1 ml of 1 x 10(6) plaque forming units/ml HCMV was injected into the vitreous cavity of 10 pigmented rabbit eyes. The eyes were examined ophthalmoscopically on days 1, 2, 3, 4 and 7 and once a week thereafter until 4 weeks after inoculation. Vitreal and retinal findings were graded from 0+ to 4+ on a scale of increasing severity. In addition, we examined the enucleated eyes 3 weeks after HCMV inoculation by histological and immunohistochemical techniques. RESULTS: All injected eyes developed vitreoretinal lesions. Vitreous opacities appeared the next day and increased until 4 days after HCMV inoculation. Whitish retinal exudates occurred on day 3 and increased until 3 weeks after HCMV inoculation. Vitreoretinal lesions then disappeared by 4 weeks after inoculation. Histological examination revealed intraretinal infiltration of inflammatory cells and disorganization of the inner retinal architecture. HCMV antigens were detected inside the retina by immunofluorescence using anti early protein antibody against HCMV. CONCLUSIONS: The results indicate that this rabbit model can be useful to develop and evaluate a new treatment modality for cytomegalovirus retinitis.

Animals↗

PubMed2001

[Function of calcium channels--newly identified from the analysis of knockout mice].

In the last 14 years, many types of calcium channels have been cloned and extensively studied using electrophysiological and pharmacological means combined with molecular biological techniques. These structure -function analyses have clarified the biophysical nature and modulation of each type of calcium channels leading to the establishment of these molecular bases. Recently, a wave of gene targeting technology has swept over the researchers in the ion channel field and several types of calcium channel knockout mice have started to be generated. Analyses of these mice have identified several novel physiological functions of the calcium channel. This report will introduce some of these studies.

English Abstract↗

PubMed2000

Cloning, genomic structure and chromosomal localization of the gene encoding mouse DNA helicase RecQ helicase protein-like 4.

Five members of the RecQ helicase family, RECQL, WRN, BLM, RECQL4 and RECQL5 have been identified in humans. WRN and BLM have been demonstrated to be the responsible genes in Werner and Bloom syndromes, respectively. RECQL4 (RecQ helicase protein-like 4) was identified as a fourth member of the human RecQ helicase family bearing the helicase domain, and it was subsequently shown to be the responsible gene in Rothmund-Thomson syndrome. Here, we isolated mouse RECQL4 and determined the DNA sequence of full-length cDNA as well as the genome organization and chromosome locus. The mouse RECQL4 consists of 3651 base pairs coding 1216 amino acid residues and shares 63.4% of identical and 85.8% of homologous amino acid sequences with human RECQL4. The RECQL4 gene was localized to mouse chromosome 15D3 distal-E1 and rat chromosome 7q34 proximal. They were mapped in the region where the conserved linkage homology has been identified between the two species. Twenty-two exons dispersed over 7 kilo base pairs and all of the acceptor and donor sites for splicing of each exon conformed to the GT/AG rule. Our observations regarding mouse RECQL4 gene will contribute to functional studies on the RECQL4 products.

Adenosine Triphosphatases↗

PubMed2000

Calcium level-responsive in-vitro zinc release from zinc containing tricalcium phosphate (ZnTCP).

The in vitro Zn release from tricalcium phosphate containing Zn (ZnTCP; 0.63, 6.17, and 12.05 Zn w/w%) was investigated. The rates of release from ZnTCP powders were measured in 25 mL of simulated body fluid (SBF) containing 10 mg/100mL Ca (SBF/H), 5 mg/100mL Ca (SBF/L), or no Ca (SBF/-) at pH 7.25, 37.0+/-0.1 degrees C. The release from 6 and 12% ZnTCP was initially very fast. The rate of release from ZnTCP decreased as the concentration of Ca in the dissolution media increased, but increased as concentration of Zn in TCP increased. The dissolution kinetics of ZnTCP followed the Hixon-Crowell equation at the initial stage of dissolution, and the initial dissolution rate constant (IDR) was calculated by the least-squares method. The effect of Ca concentration on percent IDR of ZnTCP suggested that Zn release from 0.6% ZnTCP was significantly high compared to that from 6 or 12% ZnTCP. The relationship between the amount of Ca precipitated and Zn release of various ZnTCP samples suggested that the release from 0.6% ZnTCP was significantly different compared to that from 6 and 12% ZnTCP, consistent with the data for percent Zn IDR. X-ray diffraction data suggested that 0.6% ZnTCP contained 5% hydroxyapatite, a low solubility material, which acted as seed crystal during the dissolution test.

Body Fluids↗

PubMed2000

Molecular characterization of CRMP5, a novel member of the collapsin response mediator protein family.

The CRMP (collapsin response mediator protein) family is thought to play key roles in growth cone guidance during neural development. The four members (CRMP1-4) identified to date have been demonstrated to form hetero-multimeric structures through mutual associations. In this study, we cloned a novel member of this family, which we call CRMP5, by the yeast two-hybrid method. This protein shares relatively low amino acid identity with the other CRMP members (49-50%) and also with dihydropyrimidinase (51%), whereas CRMP1-4 exhibit higher identity with each other (68-75%), suggesting that CRMP5 might be categorized into a third subfamily. The mouse CRMP5 gene was located at chromosome 5 B1. Northern blot and in situ hybridization analyses indicated that CRMP5 is expressed throughout the nervous system similarly to the other members (especially CRMP1 and CRMP4) with the expression peak in the first postnatal week. Association experiments using the yeast two-hybrid method and co-immunoprecipitation showed that CRMP5 interacts with dihydropyrimidinase and all the CRMPs including itself, except for CRMP1, although the expression profile almost overlaps with that of CRMP1 during development. These results suggest that CRMP complexes in the developing nervous system are classifiable into two populations that contain either CRMP1 or CRMP5. This indicates that different complexes may have distinct functions in shaping the neural networks.

Amino Acid Sequence↗

PubMed2000

Coincidence of ipsilateral ocular dominance peaks with orientation pinwheel centers in cat visual cortex.

Geometrical relationships among multiple cortical maps, such as those between ocular dominance and orientation maps, are a prominent feature of the brain's functional architecture. It is also well known that there is a strong bias of cortical responses toward the contralateral eye during early postnatal development. We wondered therefore whether and how such an imbalance of cortical responsiveness in a developing animal might influence the mutual geometrical relationships between orientation and ocular dominance maps in adult animals. The results of our study indicate the existence of a strong tendency for the peaks of the ipsilateral eye domains to coincide with the location of point singularities (pinwheel centers) in orientation maps. No such relationship was found for the peaks of contralateral eye domains. Computational studies reproduced similar asymmetry in the coincidence under the contralateral eye bias of inputs. Our study raised the idea that the pinwheel centers play an important role for retaining the weaker ipsilateral eye inputs during normal development.

Animals↗

PubMed2000

14-3-3 protein family members have a regulatory role in retinoic acid-mediated induction of cytokeratins in F9 cells.

We have found that the expression of five 14-3-3 protein isoforms is induced during the retinoic acid (RA)-mediated differentiation of mouse embryonal carcinoma F9 cells. The induced expression of the 14-3-3 proteins is presumed to have a role in enhancing the mitogen-activated protein kinase (MAPK) activity during RA-mediated F9 cell differentiation, because using genetically engineered budding yeast we showed that these isoforms enhanced the signaling in the MAPK cascade mainly through the interaction with Raf-1. Then we assessed the role of increased MAPK activity in F9 cell differentiation by interfering with signaling in the MAPK cascade in F9 cells. The exogenous expression of dominant-negative MEK1 efficiently abrogated RA-mediated induction of the cytokeratins EndoA and EndoC in the F9 cells. These results suggest that the 14-3-3 proteins play a role in the efficient induction of the cytokeratins during F9 cell differentiation through their signal enhancing activity in the MAPK cascade.

14-3-3 Proteins↗

PubMed2000

Molecular cloning and chromosomal mapping of a novel five-span transmembrane protein gene, M83.

In an attempt to identify novel transmembrane molecules expressed on hematopoietic cells, we identified a novel transmembrane protein gene, M83. Cloning of the full-length cDNAs of human and mouse M83 revealed that M83 encodes a type I transmembrane protein with a region containing five hydrophobic segments within the C-terminal part of the protein, suggesting that M83 is a five-span transmembrane molecule. The M83 protein was expressed on the cell surface as a glycosylated protein with a molecular mass of 84 kDa. The M83 gene was localized to human chromosome 16p13.3, mouse chromosome 17B1, and rat chromosome 10q12.3 distal. In human, M83 mRNA was highly expressed in placenta, pancreas, and lymphohematopoietic tissues including peripheral blood, spleen, and bone marrow. Among hematopoietic cells, it was highly expressed in resting T lymphocytes and was downregulated by cell activation, suggestive of its biological role related to the T cell resting status.

Amino Acid Sequence↗

PubMed2000

A mouse bone marrow stromal cell line, TBR-B, shows inducible expression of smooth muscle-specific genes.

We established an in vitro culture system which mimicked the differentiation pathway of smooth muscle cell, using TBR-B, a bone marrow stromal cell line derived from transgenic mice harboring temperature-sensitive SV40 large T-antigen gene. TBR-B cells have the potential to express smooth muscle-specific genes including h1-calponin, h-caldesmon, SM22alpha and alpha-actin, only after cultured in the differentiation medium for 2 weeks. The differentiation state of TBR-B was well controlled by using different culture medium. Using this cell line, we also found that ascorbic acid is a potent factor inducing the expression of h1-calponin and alpha-actin. TBR-B cells will serve as a useful tool for elucidating the regulatory mechanisms of smooth muscle-specific gene expression, and for identifying compounds that regulate the differentiation state of vascular smooth muscle cells.

Actins↗

PubMed2000

Calcium-level responsive controlled drug delivery from implant dosage forms to treat osteoporosis in an animal model.

The effects of plasma calcium levels on estradiol release from a self-setting apatite bone cement containing 0.5% estradiol and on the bone mineral density (BMD) of ovariectomized rats were investigated. Apatite cement consisting of an equimolar mixture of tetracalcium phosphate, dicalcium phosphate dihydrate and 0.5% beta-estradiol was prepared. The in vitro release profiles from the cements in simulated body fluid containing 0, 5 and 10 mg/100 ml calcium indicated that estradiol release rate decreased with increasing calcium concentration in the dissolution medium. After subcutaneous implantation of the cement, in vivo estradiol release in diseased rats (ovariectomized rats on a low calcium diet) was significantly higher than that in normal rats. The diseased rats maintained a low calcium level during drug release. The bone mass of the recovery model rat was greater after the experiment than before. The results suggested that the severity of osteoporosis in this animals can be reduced by the implantation of this estradiol-loaded apatite cement.

Animals↗

PubMed2000

Solid dosage form preparations from oily medicines and their drug release. Effect Of degree of surface-modification of silica gel on the drug release from phytonadione-loaded silica gels.

A surface-modified silica gel was produced to improve the surface affinity to an oily medicine, phytonadione (VK1). The effect of the degree of surface modification of the silica gel on the drug release behavior from the silica porous matrix was investigated. The silica gels were surface-modified using the silan coupling agent, 3-methacryloxypropyltrimethoxysilane (C7), octadecyltriethoxysilane (C18), or 3,3,3-trifluoropropyltrimethoxysilane (F3). A mixture of VK1 solution and surface-modified silica gel was evaporated under reduced pressure at room temperature, then the resulting powder was dried in vacuo. The degree of surface modification was evaluated based upon elementary analysis. The dissolution profiles of the samples were investigated in Japanese Pharmacopoeia XII, 1st fluid buffer (pH 1.2, 37+/-0.5 degrees C) containing 1.5% sodium lauryl sulfate. The FT-IR spectra of VK1-loaded surface-modified silica gels suggested that the amount of hydrogen-bonded VK1 with the silanol group on the gel surface decreased with increasing hydrophobicity of the silica gel. Since the modified group was rotating on the silica gel surface, and inhibited the adsorption of VK1 to the surface, the attractive molecular interaction between VK1 and the silica gel surface might decrease with increasing length of the modified functional group. However, the characteristics of the affinity of VK1 to the functional groups significantly differed among the groups. The VK1 release from the modified silica gels was initially rapid, slowed markedly after 1 h, and continued for more than 24 h. The amount of VK1 released from the modified surface silica gels by C7, C18 or F3 increased with increasing density of the surface modification group. The mean drug release moment (MDT) decreased with an increase in surface-modified group density.

Adsorption↗

PubMed2000

Highly regulated expression of subtilisin-like proprotein convertase PACE4 (SPC4) during dentinogenesis.

Expressions of mRNAs for four subtilisin-like proprotein convertases (SPCs: furin, PACE4, PC6, and PC8) and bone morphogenetic protein 4 (BMP4) in the rat molar tooth during development were analyzed by Northern blotting, reverse transcriptase-polymerase chain reaction (RT-PCR), and in situ hybridization to explore the possible involvement of SPCs in the processing of proBMPs. We found a temporospacial expression of PACE4, but not one of the other SPCs, in this tissue; i.e., RT-PCR analysis revealed that the level of PACE4 mRNA, but not that of the other SPC mRNAs became high around the second postnatal day. This increase was in good accordance with the increase in BMP4 mRNA, indicating an apparent association of these molecules with the differentiation and establishment of functional ameloblasts and odontoblasts. During dentinogenesis, PACE4 mRNA was localized in the ameloblasts and odontoblasts. These observations suggest that PACE4 plays a crucial role in dentinogenesis, especially via the activation of BMPs.

Animals↗

PubMed2000

Biochemical characterization of the Drosophila axin protein.

In the Wnt/Wingless pathway, accumulation of beta-catenin/Armadillo protein is a key regulatory step. Vertebrate Axin is a negative regulator of Wnt signaling, promoting glycogen synthase kinase-3beta-mediated phosphorylation of beta-catenin and thereby destabilizing beta-catenin. Using Drosophila cell culture systems, we demonstrated that a Drosophila homolog of Axin (Daxin) inhibits Wingless-induced Armadillo accumulation and Drosophila T-cell factor-dependent transcription induced by Wingless, Dishevelled, and Armadillo. The carboxy-terminal portion of Daxin is not essential for the inhibitory activity, but a mutant only consisting of this portion behaves as a dominant-negative protein. Moreover, interactions between Daxin and Zeste-white 3, Armadillo, Dishevelled, protein phosphatase 2A and Daxin itself were shown, providing direct evidence that Daxin is a scaffold protein in the Wingless pathway.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Molecular analysis of avian circadian clock genes.

Unlike mammals, avian circadian rhythms are regulated by a multiple oscillatory system consisting of the retina, the pineal and the suprachiasmatic nucleus in the hypothalamus. To understand avian circadian system, we have cloned Clock and Period homologs (qClock, qPer2 and qPer3) and characterized these genes in Japanese quail. Overall, qCLOCK, qPER2 and qPER3 showed approximately 79%, approximately 46% and approximately 33% amino acid identity to mCLOCK, mPER2, mPER3, respectively. Clock was mapped to quail chromosome 4 and chicken chromosome 4q1.6-q2.1. Per2 and Per3 genes were both localized to microchromosomes. qClock mRNA was expressed throughout the day, while qPer2 and qPer3 showed robust circadian oscillation in the eye and the pineal gland. All three genes were expressed in various tissues. In addition, qPer2 mRNA was induced by light, but neither qClock nor qPer3 was induced. These results can explain the molecular basis for circadian entrainment in Japanese quail and also provide new avenues for molecular understanding of avian circadian clock and photoperiodism.

Animals↗

PubMed2000

Altered pain responses in mice lacking alpha 1E subunit of the voltage-dependent Ca2+ channel.

alpha(1) subunit of the voltage-dependent Ca(2+) channel is essential for channel function and determines the functional specificity of various channel types. alpha(1E) subunit was originally identified as a neuron-specific one, but the physiological function of the Ca(2+) channel containing this subunit (alpha(1E) Ca(2+) channel) was not clear compared with other types of Ca(2+) channels because of the limited availability of specific blockers. To clarify the physiological roles of the alpha(1E) Ca(2+) channel, we have generated alpha(1E) mutant (alpha(1E)-/-) mice by gene targeting. The lacZ gene was inserted in-frame and used as a marker for alpha(1E) subunit expression. alpha(1E)-/- mice showed reduced spontaneous locomotor activities and signs of timidness, but other general behaviors were apparently normal. As involvement of alpha(1E) in pain transmission was suggested by localization analyses with 5-bromo-4-chloro-3-indolyl beta-d-galactopyranoside staining, we conducted several pain-related behavioral tests using the mutant mice. Although alpha(1E)+/- and alpha(1E)-/- mice exhibited normal pain behaviors against acute mechanical, thermal, and chemical stimuli, they both showed reduced responses to somatic inflammatory pain. alpha(1E)+/- mice showed reduced response to visceral inflammatory pain, whereas alpha(1E)-/- mice showed apparently normal response compared with that of wild-type mice. Furthermore, alpha(1E)-/- mice that had been presensitized with a visceral noxious conditioning stimulus showed increased responses to a somatic inflammatory pain, in marked contrast with the wild-type mice in which long-lasting effects of descending antinociceptive pathway were predominant. These results suggest that the alpha(1E) Ca(2 +) channel controls pain behaviors by both spinal and supraspinal mechanisms.

Acetic Acid↗

PubMed2000

Meltrin beta (ADAM19) gene: cloning, mapping, and analysis of the regulatory region.

Meltrin beta (ADAM19) is a member of the metalloprotease-disintegrin family. We report here chromosomal mapping of the mouse and rat meltrin beta genes and cloning and analysis of the mouse upstream regulatory regions. The meltrin beta transcript shows a spatially and temporally restricted expression pattern during morphogenesis, indicating that the actions of this membrane-bound protease are regulated, at least in part, at the transcriptional level. Analysis of the promoter revealed positive and negative regulatory regions upstream of the gene. The former includes a GC-box that appears to be a critical cis-element for activation of the promoter in muscle cells.

ADAM Proteins↗

PubMed2000

Abrupt change of josephson plasma frequency at the phase boundary of the bragg glass in Bi(2)Sr(2)CaCu(2)O(8+delta)

We report the first detailed and quantitative study of the Josephson coupling energy in the vortex liquid, Bragg glass, and vortex glass phases of Bi(2)Sr(2)CaCu(2)O(8+delta) by the Josephson plasma resonance. The measurements revealed distinct features in the T and H dependencies of the plasma frequency omega(pl) for each of these three vortex phases. When going across either the Bragg-to-vortex glass or the Bragg-to-liquid transition line, omega(pl) shows a dramatic change. We provide a quantitative discussion on the properties of these phase transitions, including the first order nature of the Bragg-to-vortex glass transition.

Journal Article↗