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Biomedical subjects

T Iizuka

Publications and source records attributed to T Iizuka.

At least 55 records · Page 3Linked to original sources
PubMed2001

Immunohistochemical localization of bone morphogenetic protein-2 in the oral and maxillofacial area of the human embryo.

The purpose of this study was to investigate the bone morphogenetic protein-2 (BMP-2) expression in oral and maxillofacial tissue of the human embryo. A human embryo was obtained from a patient with hysterorrhexis. The oral and maxillofacial area of the embryo was analyzed immunohistochemically using specific antibodies to BMP-2. BMP-2 was found mainly localized in developing teeth buds, jaw bone, striated and smooth muscle, spinal cord and nasal tracheal and oesophagal epithelium. However, it was not found in hair follicles. These findings are similar to those of BMP-2 and -4 gene expression in mouse and rat embryos. BMP-2 may be involved in the morphogenesis of oral and maxillofacial tissue in human embryos as well as those of other animals. These results will be of considerable benefit in the restoration and regeneration of the oral and maxillofacial tissue clinically.

Bone Morphogenetic Protein 2↗
PubMed2001

Experimental osteoinduction by recombinant human bone morphogeneticprotein 2 in tissue with low blood flow: a study in rats.

We have compared osteoinduction in soft tissues by 0, 2, 10, and 50 microg of recombinant human bone morphogenetic protein-2 (rhBMP-2) in Wistar rats with a surgically compromised blood supply and controls with a normal blood supply (n = 5 in each group). Three weeks later in the radiographic evaluation, the volume of bone formation in the low-blood-flow groups was similar to that in the controls, and was dependent on the concentration of implanted rhBMP-2. On histological evaluation much woven bone was noted in the low-blood-flow groups, but the volume of bone was less than in the controls. Alkaline phosphatase activity was less and calcium content in the low-blood-flow groups were also less than in the control rats. However, their values increased dose-dependently with implanted rhBMP-2. These results suggest that the osteoinducting activity of rhBMP-2 is reduced in tissues with a low blood supply, but higher doses of rhBMP-2 can be used in compromised tissue.

Alkaline Phosphatase↗
PubMed2001

Diagnostic value of spect bone scintigraphy for odontogenic maxillary sinusitis.

PURPOSE: The aim of this study was to assess the diagnostic value of bone SPECT for odontogenic maxillary sinusitis and bone activity in the alveolar process to clarify the pathophysiologic nature of the disease. MATERIALS AND METHODS: Computed tomography and bone SPECT with Tc-99m HMDP were performed in 28 patients with odontogenic maxillary sinusitis. Based on the findings of the computed tomographic images, the inflammatory changes in the maxillary sinus mucosa (mucosal lesions) were evaluated horizontally and vertically. For the initial diagnosis, visualization of the causative site by bone SPECT was compared with conventional radiographic and planar findings. SPECT data were used to assess bone activity by calculating the mean count ratios of the alveolar process over the cervical vertebrae. The relation of bone activity to the structure of the mucosal lesions, the presence of clinical symptoms, mucosal changes around the maxillary ostium (ostial lesions), and conventional radiolucent images around the causative teeth (periapical lesions) were assessed. RESULTS: Identification of the causative site was sufficiently specific in bone SPECT images. Bone activity was significantly correlated with the structure of the mucosal lesions, both horizontally and vertically, and with the presence of infraorbital symptoms, ostial lesions, and periapical lesions. CONCLUSIONS: It is important to view odontogenic maxillary sinusitis as a bone disease in which the bone activity associated with alveolar osteitis affects the pathophysiologic nature of the disease. Bone SPECT is valuable to make a more precise diagnosis, thereby allowing more appropriate treatment of the disease.

Adult↗
PubMed2001

A stabilized flavonoid glycoside in heat-treated Cassia alata leaves and its structural elucidation.

Heat-treated leaves of Cassia alata were studied for any change in chemical constituents using sun dried leaves as the reference standard. A high concentration of a constituent was observed in the heat-treated leaves. Spectroscopic studies revealed the structure of the constituent as kaempferol 3-gentiobioside, which has not yet been detected in the Cassia species. In a stability study disappearance of kaempferol 3-gentiobioside was noted in the sun dried leaves while there was little or no change in the kaempferol 3-gentiobioside concentration in the heat-treated leaves when incubated in an aqueous solution, suggesting a possible presence of enzymatic activities in the sun dried leaves. Therefore, heat-treatment may be a good method to stabilize kaempferol 3-gentiobioside in Cassia alata leaves.

Cassia↗
PubMed2001

Haliangicin, a novel antifungal metabolite produced by a marine myxobacterium. 1. Fermentation and biological characteristics.

Haliangicin, a novel beta-methoxyacrylate antibiotic with a conjugated tetraene moiety, was isolated from the culture broth of a marine myxobacterium. A bacterium tentatively named as Haliangium luteum required 2-3% NaCl for the growth and production of haliangicin. Haliangicin inhibits the growth of a wide spectrum of fungi but was inactive against bacteria. In mitochondrial respiratory chains, haliangicin interfered the electron flow within the cytochrome b-c1 segment.

Antifungal Agents↗
PubMed2001

In vitro and in vivo studies of a bone morphogenetic protein-2 expressing adenoviral vector.

BACKGROUND: Bone morphogenetic proteins (BMPs) play important roles in the migration of osteoblast progenitor cells, the proliferation of mesenchymal cells, and their differentiation into chondrogenic and osteogenic cells. However, the optimum procedure to deliver BMPs remains unknown. To examine the effectiveness of a gene transfer procedure for the delivery of BMP-2, we constructed a human BMP-2-expressing replication-deficient adenoviral vector, AxCAOBMP-2, and evaluated its osteoinductive activity in vitro and in vivo. METHODS: C2C12 myoblasts were infected in vitro with this viral vector or an Escherichia coli LacZ gene-expressing control adenovirus vector (AxCALacZ). Twenty-four hours after the infection, indirect immunofluorescence was performed. On day 5 after the infection, alkaline phosphatase (ALP) in the cells and osteocalcin in the culture medium were measured. Furthermore, to examine the effectiveness of gene transfer of BMP-2 in vivo, we evaluated osteoinduction by AxCAOBMP-2, under transient immunosuppression with cyclophosphamide, given at a dose of 125 mg/kg intraperitoneally the day before injection of the adenoviral vector. Twenty-five microliters of AxCAOBMP-2 (8.75 x 10(8) plaque-forming units [pfu], Group I) and AxCALacZ (1.75 x 10(8) pfu, control group) and 5 microl of AxCAOBMP-2 (1.75 x 10(8) pfu, Group II) were injected into a right calf muscle of Wistar rats. On day 21, bone formation in each group was investigated radiologically and histologically. RESULTS: Abundant BMP-2 expression in C2C12 cells infected with this viral vector was confirmed by immunofluorescence. C2C12 cells transferred with the BMP-2 gene by this vector produced ALP in the cells and also produced and secreted osteocalcin in the culture medium. Osteoinduction was found only in the AxCAOBMP-2 treated groups with immunosuppression. Osteoinduction activity was higher in Group I than in Group II. CONCLUSION: This study demonstrated the osteoinductive activity in vitro and in vivo by an adenoviral vector carrying the BMP-2 gene. CLINICAL RELEVANCE: Gene therapy with AxCAOBMP-2 under transient immunosuppression may be useful for bone reconstruction.

Adenoviridae↗
PubMed2000

Roles of Ile209 and Ile210 on the heme pocket structure and regulation of histidine kinase activity of oxygen sensor FixL from Rhizobium meliloti.

FixL is a sensor histidine kinase having a heme-containing domain as an O(2) sensing site. In the study presented here, Ile209 and Ile210 located near the heme iron of the heme domain of Rhizobium meliloti FixL (RmFixL) were mutated, and the mutational effects on the regulation of the kinase activity and the heme pocket structure were examined by the autophosphorylation assay and UV-visible absorption and resonance Raman (RR) spectroscopies. The mutation of these residues disrupted the regulation of the kinase activity by the sensor (heme) domain, indicating that Ile209 and Ile210 play important roles in the signal transduction between the heme and the kinase domains. By measurement of the resonance Raman and optical absorption spectra of Ile209 and Ile210 mutants in several oxidation, spin, and ligation states, it was found that both residues are highly flexible, and their side chains sterically interact with the O(2) ligand, when it binds to the heme iron. On the basis of the results, we propose an O(2) sensing mechanism of RmFixL; the kinase activity is regulated via conformational changes of Ile209 and Ile210 induced by the O(2) binding to the sensory center.

Bacterial Proteins↗
PubMed2000

PAPIN. A novel multiple PSD-95/Dlg-A/ZO-1 protein interacting with neural plakophilin-related armadillo repeat protein/delta-catenin and p0071.

A neural plakophilin-related armadillo repeat protein (NPRAP)/delta-catenin interacts with one of Alzheimer disease-related gene products, presenilin 1. We have previously reported the interaction of NPRAP/delta-catenin with synaptic scaffolding molecule, which is involved in the assembly of synaptic components. NPRAP/delta-catenin also interacts with E-cadherin and beta-catenin and is implicated in the organization of cell-cell junctions. p0071, a ubiquitous isoform of NPRAP/delta-catenin, is localized at desmosomes in HeLa and A431 cells and at adherens junctions in Madin-Darby bovine kidney cells. We have identified here a novel protein interacting with NPRAP/delta-catenin and p0071 and named this protein plakophilin-related armadillo repeat protein-interacting PSD-95/Dlg-A/ZO-1 (PDZ) protein (PAPIN). PAPIN has six PDZ domains and binds to NPRAP/delta-catenin and p0071 via the second PDZ domain. PAPIN and p0071 are ubiquitously expressed in various tissues and are localized at cell-cell junctions in normal rat kidney cells and bronchial epithelial cells. PAPIN may be a scaffolding protein connecting components of epithelial junctions with p0071.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Sensory mechanism of oxygen sensor FixL from Rhizobium meliloti: crystallographic, mutagenesis and resonance Raman spectroscopic studies.

FixL of Rhizobium meliloti (RmFixL) is a sensor histidine kinase of the two-component system, which regulates the expression of the genes related to nitrogen fixation in the root nodule in response to the O(2) levels. The crystal structure of the sensor domain of FixL (RmFixLH), which contains a heme (Fe-porphyrin) as a sensing site, was determined at 1.4 A resolution. Based on the structural and spectroscopic analyses, we propose the O(2) sensing mechanism that differs from the case proposed in BjFixLH as follows; conformational changes in the F/G loop, which are induced by steric repulsion between the bent-bound O(2) and the Ile209 side-chain, would be transmitted to the histidine kinase domain. Interaction between the iron-bound O(2) and Ile209 was also observed in the resonance Raman spectra of RmFixLH as evidenced by the fact that the Fe-O(2) and Fe-CN stretching frequencies were shifted from 575 to 570 cm(-1) (Fe-O(2)), and 504 to 499 cm(-1), respectively, as the result of the replacement of Ile209 with an Ala residue. In the I209A mutant of RmFixL, the O(2) sensing activity was destroyed, thus confirming our proposed mechanism.

Bacterial Proteins↗
PubMed2000

Effect of elcatonin on osteoinduction by recombinant human bone morphogenetic protein-2.

To evaluate the effect of elcatonin on osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), 5 microg of rhBMP-2 was implanted into intramuscular sites of rats. For 14 days after the implantation, elcatonin was administered intraperitoneally with total dosage of 80 U, 8 U, and 0.8 U, respectively. For the control group, only physiological saline was administered. At 21 days after implantation, the area of the oval shadow in the radiologic findings depended on the elcatonin dose and the amount of trabecular bone and the number of osteoblasts observed in the histologic findings depended on the dosage of elcatonin. The values of ALP activity and Ca content also showed an elcatonin dose dependency. These results suggested that elcatonin is effective in enhancing osteoinduction by rhBMP-2 within the dose range of this study, and that elcatonin has an anabolic effect on osteoblasts in addition to an antiresorptive effect.

Alkaline Phosphatase↗
PubMed2000

Stage-specific expression of mucosal addressin cell adhesion molecule-1 during embryogenesis in rats.

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is essential for lymphocyte trafficking to gut-associated lymphoid tissues and is implicated in inflammatory disorders in the gut and pancreatic islets. In this study, we examined the functional role of MAdCAM-1 during rat ontogeny using newly generated specific mAb. As previously observed in mice and humans, MAdCAM-1 was preferentially expressed in high endothelial venules (HEV) in gut-associated lymphoid tissues and venules of lamina propria in adult rats. Lymphocyte rolling and adhesion on HEV in Peyer's patches (PP) were completely abrogated with neutralizing anti-MAdCAM-1 mAb, in agreement with the notion that MAdCAM-1 is the principal HEV ligand for lymphocyte rolling and adhesion in adult PP. In the developing gastrointestinal tract, MAdCAM-1 was widely expressed in the venules of the lamina propria of fetal rats. In addition, MAdCAM-1 was also expressed in follicular dendritic cells in the neonatal PP. Interestingly, MAdCAM-1 expression was found also in nonmucosal tissues during ontogeny. MAdCAM-1 was transiently expressed in blood vascular endothelial cells in the fetal skin and neonatal thymus. Notably, MAdCAM-1-positive blood vessels were localized mainly in the cortico-medullary junction in the neonatal thymus and about 10-20% of thymocytes, most of which were either CD4, CD8 double positive or single positive specifically reacted with soluble MAdCAM-1 via integrin alpha4beta7. After birth, MAdCAM-1 expression in thymus blood vessels disappeared and concomitantly, the soluble MAdCAM-1-reactive thymocytes were rapidly down-regulated. Our results suggest that MAdCAM-1 functions as a vascular addressin in not only mucosal, but also nonmucosal lymphoid tissues during ontogeny.

Aging↗
PubMed2000

Osteoinduction by bone morphogenetic protein-2 via adenoviral vector under transient immunosuppression.

To examine the effectiveness of gene transfer of bone morphogenetic protein (BMP)-2 in vivo, we evaluated osteoinduction by an adenoviral vector, AxCAOBMP-2, under transient immunosuppression with an immunosuppression drug (cyclophosphamide), which was given at a dose of 125 mg/kg intraperitoneally the day before vector injection. Twenty-five microliters of AxCAOBMP-2 (8.75 x 10(8) pfu, Group I) and AxCALacZ (1.75 x 10(8) pfu, control group) and 5 microliter of AxCAOBMP-2 (1.75 x 10(8) pfu, Group II) were injected into a right calf muscle. On day 21, induced bone in each group was investigated radiologically, histologically, and biochemically. The finding of osteoinduction was only seen in the AxCAOBMP-2-treated groups with immunosuppression. The activity of osteoinduction in Group I was higher than that in Group II. These results suggest that gene therapy with AxCAOBMP-2 under transient immunosuppression may be useful for bone reconstruction.

Adenoviridae↗
PubMed2000

Localization of BAI-associated protein1/membrane-associated guanylate kinase-1 at adherens junctions in normal rat kidney cells: polarized targeting mediated by the carboxyl-terminal PDZ domains.

Brain-specific angiogenesis inhibitor (BAI)-associated protein (BAP)1 (also called membrane-associated guanylate kinase [MAGI]-1) is composed of six PSD-95/Dlg-A/ZO-1 (PDZ) domains, two WW domains, and one guanylate kinase (GK) domain. We previously reported that BAP1 is localized at tight junctions in Madine Darby canine kidney (MDCK) cells and intestinal epithelial cells. Here, we have determined the localization of BAP1 in normal rat kidney (NRK) cells that do not form tight junctions. BAP1 was colocalized with E-cadherin along the lateral membrane, suggesting its localization at adherens junctions. Green fluorescent protein (GFP)-BAP1 was distributed in the cytosol in separate NRK cells, and accumulated to the cell-cell contacts when NRK cells have contact with each other. The GFP-BAP1 mutant containing either the first PDZ and GK domains or the WW and second PDZ domains was localized in the cytosol and the nucleus. The GFP-BAP1 mutant containing the second to fourth PDZ domains was distributed in the cytosol. The construct containing the fifth and sixth PDZ domains was localized at the cell-cell contacts along the lateral membrane and slightly in the nucleus, whereas the construct lacking the fifth and sixth PDZ domains was localized in the cytosol and in the nucleus. BAP1 was tyrosine-phosphorylated in vivo, but the tyrosine phosphorylation of BAP1 was not correlated with its localization. These results suggest that the signal in the carboxyl-terminal PDZ domains functions dominantly in vivo to target BAP1 to the lateral membrane, although potential nuclear localization signals exist in the N-terminal region of BAP1.

Adherens Junctions↗
PubMed2000

Induction and maintenance of immune effector cells in the gastric tissue of mice orally immunized to Helicobacter pylori requires salivary glands.

BACKGROUND & AIMS: Helicobactor pylori mostly colonizes the gastric mucus that contains salivary antibodies. We studied the role of saliva in the induction and maintenance of gastric immunity conferred by oral vaccination against H. pylori. METHODS: C57BL/6 mice underwent a sialoadenectomy before and after intragastric immunization using whole-cell sonicates of H. pylori and cholera toxin as an adjuvant. At 1 and 6 months after oral inoculation, we assessed the density of the H. pylori colonizing the stomach, specific antibodies in gastric secretion and sera, and the constituents of cellular infiltrates in the tissue. RESULTS: A sialoadenectomy before, but not after, immunization abrogated protection by the vaccination at 1 month after inoculation. Protected mice had more neutrophils, plasma cells, and lymphocytes, but fewer eosinophils, in the gastric tissue than nonprotected mice. Protected mice had a greater increase of immunoglobulin (Ig) G1 specific to H. pylori than IgG2a in sera. At 6 months after inoculation, oral immunization was less effective in mice who had a sialoadenectomy than in control immunized mice. The antibody titers in both gastric secretion and in sera did not correlate with the density of bacteria colonizing the stomach. CONCLUSIONS: It is suggested that, in intragastric immunization against H. pylori, saliva is necessary for both the induction and maintenance of optimal immunity in the stomach. Effective immunity was associated with an increased number of neutrophils and lymphocytes in gastric tissue.

Administration, Oral↗
PubMed2000

Analysis of proteins encoded in the bipartite genome of a new type of parvo-like virus isolated from silkworm - structural protein with DNA polymerase motif.

Bombyx mori densonucleosis virus type 2 (BmDNV-2) is a small, spherical virus containing two complementary single-stranded linear DNA molecules (VD1, VD2). BmDNV-2 is a new type of virus with a unique, yet unspecified replication mechanism which is different from that of parvoviruses (Bando, H., Choi, H., Ito, Y., Nakagaki, M. , Kawase, S., 1992. Structural analysis on the single-stranded genomic DNAs of the virus newly isolated from silkworm: the DNA molecules share a common terminal sequence, Arch. Virol. 124, 187-193; Bando, H., Hayakawa, T., Asano, S., Sahara, K., Nakagaki, M. , Iizuka, T., 1995. Analysis of the genetic information of a DNA segment of a new virus from silkworm, Arch. Virol., 140, 1147-1155; Hayakawa, T., Asano, S., Sahara, K., Iizuka, T., Bando, H., 1997. Detection of replicative intermediate with closed terminus of Bombyx densonucleosis virus. Arch. Virol. 142, 1-7). Recent analyses on the genomic information of BmDNV-2 identified open reading frames which code for three tentative nonstructural proteins and four (VP1 to 4) of the six known structural proteins (Bando, H., Hayakawa, T., Asano, S., Sahara, K., Nakagaki, M., Iizuka, T., 1995. Analysis of the genetic information of a DNA segment of a new virus from silkworm, Arch. Virol., 140, 1147-1155; Nakagaki et al., in preparation). In this report we demonstrate that the two largest ORFs, VD1-ORF1 and VD2-ORF1, code for the two remaining structural proteins. In addition, computer-assisted analysis revealed that the structural protein encoded in VD1-ORF1 contains sequences conserved among various DNA polymerases, and showed an evolutionary relationship with the DNA polymerases involved in protein-primed replication.

Amino Acid Motifs↗
PubMed2000

Bone induction by Escherichia coli -derived recombinant human bone morphogenetic protein-2 compared with Chinese hamster ovary cell-derived recombinant human bone morphogenetic protein-2.

Most recombinant human bone morphogenetic protein (rhBMP) is currently obtained from Chinese hamster ovary (CHO) cells. If rhBMP with more activity could be derived from Escherichia coli (E. coli), a large quantity of rhBMP could be produced at low cost. The bone-inducing ability of an E. coli -derived rhBMP-2 (ErhBMP-2) variant with an N-terminal sequence was examined and compared with CHO cell-derived rhBMP-2 (CrhBMP-2). Two, 10, or 50 microgram of ErhBMP-2 or CrhBMP-2 was mixed with 3mg of atelopeptide type I collagen as the carrier, and specimens were implanted into the calf muscle pouches of Wistar rats (n= 5 in each group). Three weeks later, new bone had formed in all the ErhBMP-2-implanted and CrhBMP-2-implanted muscles. Radiographic and histological examinations showed that the bone induced by ErhBMP-2 had a large hollow bone matrix with more fatty marrow than the bone induced by CrhBMP-2. Quantitative analysis indicated that the activity of ErhBMP-2 was similar to that of CrhBMP-2, so ErhBMP-2 may be useful for inducing bone formation.

Alkaline Phosphatase↗