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Koichi Ito

Publications and source records attributed to Koichi Ito.

At least 19 recordsLinked to original sources
PubMed2025

Loss and Gain of Aqp10 Paralogs With Broad Solute Selectivity in Anguillid Eels.

Aquaporin (Aqp) 10 is a member of the aquaglyceriporin family, which transports small, uncharged solutes in addition to water. Although the solute selectivity of aquaglyceroporins varies, the mechanism of solute selectivity has not yet been fully elucidated. The common ancestor of ray-finned fish possessed two paralogous genes for aquaporin 10, aqp10.1 and aqp10.2, which produce Aqps with different solute selectivities. Most teleosts possess one or more ohnologs derived from aqp10.1 and aqp10.2; however, the common ancestor of Anguilliformes species lost all aqp10.1-derived ohnologs. Anguilliformes species, except Anguilla species, have one aqp10.2b, but recent tandem duplications in the European eel have generated three aqp10.2b paralogs (aqp10.2b1-aqp10.2b3), whose activities remain ambiguous. In this study, we found that the four sites forming the aromatic/arginine (ar/R) selectivity filter in European eel Aqp10.2b1 were identical to those in Aqp10.2b of other species. However, the Y residue at position 3 was replaced with G in the ar/R selectivity filter of Aqp10.2b2 and b3. When expressed in Xenopus oocytes, Aqp10.2b2 and b3 showed higher permeability to urea and boric acid than Aqp10.2b1, indicating that Aqp10.2b2 and b3 acquired broad solute selectivity similar to that of Aqp10.1, which was lost in the ancestral Anguilliformes species. Urea and boric acid permeabilities of Aqp10.2b1 increased when the Y residue at position 3 of the ar/R selectivity filter was replaced with G. Overall, our results outline the history of the loss and gain of Aqp10 paralogs with broad solute selectivity in anguillid eels.

Animals↗
PubMed2007

Reduced action of polypeptide release factors induces mRNA cleavage and tmRNA tagging at stop codons in Escherichia coli.

Certain C-terminal sequences of nascent peptide cause an efficient protein tagging by tmRNA system at stop codons in Escherichia coli. Here, we demonstrate that both mRNA cleavage and tmRNA tagging occur at UAG stop codon recognized specifically by polypeptide release factor 1 (RF-1) when the activity of RF-1 is reduced by a mutation in the prfA gene without requirement of particular C-terminal sequences of nascent peptide. The tmRNA tagging and mRNA cleavage in the prfA mutant were eliminated when the wild-type RF-1 but not RF-2 was supplied from plasmid. In addition, depletion of either RF-1 or RF-2 induces endonucleolytic cleavage and tmRNA tagging at UAG or UGA stop codons respectively. We conclude that ribosome stalling at the cognate stop codon caused by reduced activity or expression of RF-1 or RF-2 is responsible for mRNA cleavage. The present data along with our previous studies strongly suggest that ribosome stalling leads to endonucleolytic cleavage of mRNA in general resulting in non-stop mRNA and that the 3' end of non-stop mRNA is probably only target for the tmRNA system.

Codon, Terminator↗
PubMed2007

Effects of ipriflavone on augmented bone using a guided bone regeneration procedure.

: This study investigated the effects of ipriflavone (IP) on augmented bone using a guided bone regeneration (GBR) procedure. In 15 rabbits, two titanium caps were placed into calvarial bone for GBR. The animals were divided into three groups: the No-IP (no intake of IP), Post-IP (IP orally, 10 mg/kg/day after GBR), and Pre-IP (IP intake beginning before GBR) groups. One cap was removed from each rabbit after 3 months, and the remaining site was a control. One month after one cap removal, all the animals were euthanized, and histologic and histomorphometric analyses were performed. In all of the groups, the newly generated tissue was of varying size, and it consisted of thin pieces of mineralized bone and large marrow spaces with fat cells and some hematopoietic cells. In all of the control sites, the newly generated tissue was noted and almost filled the space under the cap. There was a significant difference between groups No-IP and Pre-IP (93.8+/-4.6% vs. 98.5+/-0.8%, P<0.05). The tissue generated at the test sites in all of the groups was resorbed, and its original shape and volume were not maintained 1 month after one cap removal. In particular, the greatest percentage, approximately 20% of the newly generated tissue, was resorbed in the No-IP group (93.8+/-4.6% vs. 73.9+/-3.7%, P<0.05), and approximately 11% and 15% in groups Post-IP and Pre-IP, respectively. The relative amount of mineralized bone generated at the control and test sites was significantly larger in groups Post-IP and Pre-IP when compared with group No-IP, except for the test site between groups No-IP and Post-IP (P<0.05). Therefore, the amount of mineralized tissue generated appeared to increase with an increase in the total IP dose. Within the limitations of this rabbit experimental model, we conclude that the daily intake of IP before or after GBR inhibits the resorption of augmented tissue and would be useful for improving the quality of newly generated bone beyond the skeletal envelope.

Adipose Tissue↗
PubMed2007

Enamel matrix derivative stimulates osteogenesis- and chondrogenesis-related transcription factors in C3H10T1/2 cells.

Our purpose was to determine how enamel matrix derivative (EMD) affects the expression of osteogenesis- and chondrogenesis-related transcription factors in undifferentiated mesenchymal cells. C3H10T1/2 cell line, a typical pluripotential mesenchymal cell line, was cultured with or without EMD for up to 7 d. Expression of mRNAs encoding osteogenesis- and chondrogenesis-related transcription factors (Runx2, Osterix, AJ18, Dlx5, Msx2, Sox5, Sox9 and Zfp60) was measured using real-time polymerase chain reaction. Runx2 and Sox9 protein expression and the presence of bone morphogenetic protein (BMP)-6-like molecules in EMD were determined by Western blotting. EMD substantially increased mRNA levels of osteogenesis- and chondrogenesis-related transcription factors. EMD also induced Runx2 and Sox9 protein expression. Western blotting analysis of EMD using anti-BMP-6 antibody revealed immunoreactive bands corresponding to about 14 kDa and 60 kDa. These results suggest that EMD stimulates osteogenesis- and chondrogenesis-related transcription factors, and these activities may be mediated, at least in part, by BMP-6 in EMD.

Animals↗
PubMed2007

Polymorphisms of the factor VII gene associated with the low activities of vitamin K-dependent coagulation factors in one-month-old infants.

Despite administration of vitamin K (VK), some infants show lower activity of VK-dependent coagulation factors and they could develop intracranial hemorrhage. For preventing VK deficiency bleeding (VKDB) in infants, oral administration of VK and a screening test for VK deficiency are carried out in Japan. For the screening, the total activity of VK-dependent coagulation factors is measured using a commercial product, Normotest. This study was undertaken to clarify the importance of the following genetic and environmental factors on the coagulation status in one-month-old infants: two polymorphisms in the factor VII gene, -323P0/10 (a 10-bp insertion in the promoter region at position -323) and R353Q (the replacement of arginine [R] with glutamine [Q] at residue 353) and sex, age, gestational age, birth weight, and feeding regimen. Two hundred Japanese infants (34.6 +/- 4.0 days old) were screened for VK-dependent coagulation activity with Normotest and were genotyped for the two polymorphisms. Among the subjects screened, 18 infants (9%) carried the P10 allele and 26 (13%) carried the R353Q allele. Multiple regression analysis showed that the 10-bp inserted (P10) allele or the Q allele was associated with the lower coagulation activities. The coagulation activities for the R/Q genotype were significantly lower than those for the R/R genotype and those for the P0/P10 genotype were significantly lower than those for the P0/P0 genotype. Therefore, infants who carry the P10 allele or the Q allele show lower activity of VK-dependent coagulation factors. These infants may have a higher risk of VKDB manifestation.

Birth Weight↗
PubMed2006

Low-intensity pulsed ultrasound stimulates osteogenic differentiation in ROS 17/2.8 cells.

There have been no studies investigating the effects of the mechanical stimulation provided by Low-intensity pulsed ultrasound (LIPUS) treatment on periodontal disease accompanying bone loss. LIPUS is known to accelerate mineralization and bone regeneration, but the precise cellular mechanism is unclear. Here, we investigated the effect of LIPUS on osteogenesis by examining the effect of LIPUS stimulation on cell proliferation, alkaline phosphatase (ALPase) activity, osteogenesis-related gene expression, and mineralized nodule formation in a rat osteosarcoma cell line. The cells were cultured in medium with or without the addition of LIPUS stimulation. The ultrasound signal consisted of 1.5 MHz at an intensity of 30 mW/cm(2) for 20 min for all cultures. LIPUS stimulation did not affect the rate of cell proliferation. ALPase activity was increased at day 7 of culture after LIPUS stimulation. Real-time PCR analysis indicated that LIPUS significantly increased the expression of mRNA for the transcription factors Runx2, Msx2, Dlx5, and Osterix and for bone sialoprotein, whereas the mRNA expression of AJ18 was significantly reduced. The mineralized nodule formation and the calcium content in mineralized nodules were markedly increased on day 14 of culture after LIPUS stimulation. Our study demonstrates that LIPUS stimulation directly affects osteogenic cells, leading to mineralized nodule formation. In view of the widespread use of LIPUS for the clinical therapy of periodontal disease, it is likely that LIPUS has an important influence on key functional activities of osteoblasts in alveolar bone.

Alkaline Phosphatase↗
PubMed2006

Management of differentiated thyroid carcinoma with radioiodine and recombinant human TSH.

Recombinant human TSH (rhTSH) brought revolutionary change in the management of patients with differentiated thyroid cancer since it was first approved for clinical use in the United States and Europe. Follow-up management of differentiated thyroid cancer is based on the detection of recurrent or residual cancer, traditionally achieved by measurement of serum thyroglobulin level and various imaging techniques including 131I whole body scan. Previously, TSH stimulation was achieved only by induction of hypothyroidism following withdrawal of thyroid hormone. However, hypothyroidism is uncomfortable and is association with a reduction in quality of life. RhTSH can provide elevated TSH without making patients hypothyroid. In the United States and Europe, rhTSH is approved for use only in monitoring of differentiated thyroid cancer. In this article, we reviewed the role of rhTSH in the diagnosis and management of differentiated thyroid cancer.

Carcinoma↗
PubMed2006

Effects of low-intensity pulsed ultrasound on the differentiation of C2C12 cells.

Low-intensity pulsed ultrasound (LIPUS) is known to accelerate bone regeneration, but the precise cellular mechanism is still unclear. The purpose of this study was to determine the effect of LIPUS on the differentiation of pluripotent mesenchymal cell line C2C12. The cells were cultured in differentiation medium with or without the addition of LIPUS stimulation. The ultrasound signal consisted of 1.5 MHz at an intensity of 70 mW/cm2 for 20 min for all cultures. To verify the cell lineage after LIPUS stimulation, mRNA expression of cellular phenotype-specific markers characterizing osteoblasts (Runx2, Msx2, Dlx5, AJ18), chondroblasts (Sox9), myoblasts (MyoD), and adipocytes (C/EBP, PPARgamma) was studied using real-time polymerase chain reaction analysis. The protein expression of Runx2 and activated phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (p38 MAPK) were performed using Western blotting. The mRNA expression of Runx2, Msx2, Dlx5, AJ18, and Sox9 was increased markedly by the LIPUS stimulation, whereas the expression of MyoD, C/EBP, and PPARgamma was drastically decreased. In the Western blot analysis, LIPUS stimulation increased Runx2 protein expression and phosphorylation of ERK1/2 and p38 MAPK. Our study demonstrated that LIPUS stimulation converts the differentiation pathway of C2C12 cells into the osteoblast and/or chondroblast lineage via activated phosphorylation of ERK1/2 and p38 MAPK.

Animals↗
PubMed2006

Prevalence of hepatitis E virus infection in Japanese children.

BACKGROUND: Recently, sporadic cases of acute hepatitis and fulminant hepatitis caused by hepatitis E virus (HEV) have been reported in Japan. However, few reports have addressed the issue of HEV infection during childhood. METHODS: This study included 5 patients with fulminant hepatitis, 30 patients with acute hepatitis, and 309 patients without history of hepatic dysfunction or hepatitis in childhood as control. RNA was extracted from each serum sample, and HEV specific reverse-transcriptase polymerase chain reaction was performed. Anti-HEV immunoglobulin (Ig)M and IgG were measured by enzyme-linked immunoadsorbent assay. RESULTS: HEV RNA, anti-HEV IgM, and anti-HEV IgG were not detected in the sera of any of the five patients with fulminant hepatitis. In the 30 patients with acute hepatitis, only one (3.3%) was positive for anti-HEV IgG, and all were negative for anti-HEV IgM and HEV RNA. Of the 309 control patients, 8 (2.6%) were positive for anti-HEV IgG, and 2 (0.6%) were positive for anti-HEV IgM, respectively. CONCLUSION: The result of patients with fulminant hepatitis suggests that HEV is an unlikely cause of fulminant hepatitis in children. However, the detection rate of anti-HEV IgG shows that a history of HEV infection is not so rare among children in Japan.

Acute Disease↗
PubMed2006

Ribosomal protein L11 mutations in two functional domains equally affect release factors 1 and 2 activity.

Bacterial release factors (RFs) 1 and 2 catalyse translation termination at UAG/UAA and UGA/UAA stop codons respectively. It has been shown that limiting the amount of ribosomal protein L11 affects translation termination at UAG and UGA differently. To understand the functional interplay between L11 and RF1/RF2, we isolated 21 distinct mutations in L11 as suppressors of either temperature-sensitive (ts) RF1/RF2 strains or read-through mutants of lacZ nonsense (UAG or UGA) strains. 10 of 21 mutants restored ts lethal growth of RF1 and/or RF2 strains. All the selected L11 mutants, including the RF1ts- and RF2ts-specific suppressors, had the same effect, either enhancing or reducing, on UAG and UGA termination efficiency in vivo. The specific properties of the selected L11 mutations remained unchanged in an RF3 deletion strain. Moreover, ribosomes absent of L11 had equally reduced activity for both RF1- and RF2-mediated peptide release in vitro. These results suggest that, unlike the previous notion, L11 has a common, cooperative role with RF1 and RF2. These L11 mutations were located on the surface of two domains of L11, and interpreted to affect the interaction between L11 and rRNA or the RFs thereby leading to the altered translation termination.

Codon, Terminator↗
PubMed2006

Effects of bioactive glass on bone augmentation within a titanium cap in rabbit parietal bone.

BACKGROUND: The condition of alveolar bone influences the success and subsequent esthetics of implant treatment. This study investigated the early effects of bioactive glass (BG) on bone augmentation within a hemispherical titanium cap in rabbit parietal bone. METHODS: Twelve adult male Japanese white rabbits were used. One titanium cap (test site) was packed with BG in a collagen gel, and the other (control site) was packed with the collagen gel alone. After 1 and 3 months, animals were euthanized, and the experimental area was examined using fluorescence and light microscopy. RESULTS: Newly generated bone was observed at 1 and 3 months of healing. Although bone was also generated without BG, newly mineralized bone was generated sooner with BG present for guided bone augmentation than without BG. At 1 and 3 months, the BG was not bioabsorbed completely, and some particles remained. CONCLUSION: New bone is generated at an early stage of bone formation using BG for bone augmentation.

Animals↗
PubMed2006

Profiling the cytokines in gingival crevicular fluid using a cytokine antibody array.

BACKGROUND: Various compounds have been detected in gingival crevicular fluid (GCF) as indicators of periodontal disease activity. Therefore, the analysis of GCF may be especially beneficial for diagnosing current periodontal status and addressing the effects of treatment. Moreover, the identification of new markers in GCF may also contribute to elucidating novel mechanisms involved in periodontal disease. This study sought novel marker proteins specific to chronic periodontitis by profiling cytokines in GCF using a cytokine antibody array system. METHODS: Human cytokine array V, which detects 79 cytokines on one membrane, was used to determine the profile of cytokines in GCF from seven subjects with chronic periodontitis and seven subjects with healthy periodontia. The profile was exposed to x-ray film and quantified using image analysis software. Healthy and diseased sites were compared statistically. RESULTS: We detected 10 cytokines in periodontally healthy sites and 36 cytokines in periodontally diseased sites. Interleukin-8 (IL-8) and transforming growth factor-beta 2 (TGF-beta2) were detected at high levels in healthy and diseased subjects. There were significant differences between healthy and diseased subjects in the levels of tissue inhibitor of metalloproteinases-2 (TIMP-2), tumor necrosis factor-beta (TNF-beta), growth-related oncogene (GRO), interferon-inducible protein-10 (IP-10), angiogenin (Ang), vascular endothelial growth factor (VEGF), insulin-like growth factor binding protein-3 (IGFBP-3), osteoprotegerin (OPG), epidermal growth factor (EGF), glial-derived neurotrophic factor (GDNF), pulmonary and activation-regulated chemokine (PARC), oncostatin M (OSM), fibroblast growth factor-4 (FGF-4), IL-16, homologous to lymphotoxins (LIGHT), and placenta growth factor (PlGF). Of these, the newly detected cytokines were GRO, Ang, IGFBP-3, GDNF, PARC, OSM, FGF-4, IL-16, LIGHT, and PlGF. CONCLUSIONS: In this study, we detected several cytokines in GCF using a cytokine antibody array system, including both inflammatory cytokines and various growth factors. Therefore, periodontal disease may participate in the wound healing process and in tissue destruction via the inflammatory process. Our results suggest that the quantification of these cytokines in GCF provides useful information for the diagnosis of periodontal disease status.

Aged↗
PubMed2006

[Survey on the quality of commercial Nigari (crude magnesium chloride [sea water])].

Contents of minerals (Mg, Ca, Na and K), anions (SO4(2-), Br- and Cl) and heavy metals (Pb, Cd, Zn, Hg and As) were determined in 17 commercial samples of Nigari, 15 samples of crude magnesium chloride (sea water) products as a food additive and 2 magnesium-containing foods. Obtained values were compared with the specifications proposed in a draft of the eighth edition of Japan's Specifications and Standards for Food Additives. Out of 15 food additive samples, only 5 samples satisfied the specification. Since the Joint FAO/WHO Expert Committee on Food Additives (JECFA) proposed to lower the limits of heavy metals in food additives, a simple method was developed for the determination of low levels of Pb and Cd by extracting chelates of these metals with organic solvents. The quantification limits for Pb and Cd were 0.5 microg/g and 0.05 microg/g, respectively. It was estimated from the SO4(2-)/Ca ratios that 15 samples were sea water evaporation products, and the remaining 2 were ion-exchange membrane process products. No pollution with heavy metals was found in any of the samples.

Food Additives↗
PubMed2006

Effects of different sizes of beta-tricalcium phosphate particles on bone augmentation within a titanium cap in rabbit calvarium.

This study evaluated the effects of different sizes of beta-TCP particles on bone augmentation within a titanium cap. In 20 rabbits, the calvarium was exposed and a circular groove was prepared. After marrow penetration, a standardized hemispherical titanium cap was placed in the circular grove. The cap was filled with small-sized (100-250 microm) or medium-sized (250-500 microm) beta-TCP particles for the experimental site and without beta-TCP for the control site. After one and three months of healing, the animals were euthanized and examined histologically. There was a statistically significant difference in the amount of mineralized bone generated between the experimental and control groups in the three-month specimens. Furthermore, the medium-sized particles showed significantly more mineralized bone than did the small-sized particles. Based on these findings, we suggested that beta-TCP might be effective for bone formation and that medium-sized particles are more useful than small-sized particles in bone maturation.

Animals↗
PubMed2006

Treatment of Miller Class III recessions with enamel matrix derivative (Emdogain) in combination with subepithelial connective tissue grafting.

This report examines the clinical parameters and radiographic characteristics of two patients with Class III gingival recession who were treated with combined connective tissue grafting and root coverage with enamel matrix derivative. Both patients presented with multiple Class III recessions in the mandibular central incisors. Root coverage was achieved by connective tissue grafting in conjunction with the application of enamel matrix derivative. Soft tissue coverage of the root surfaces was achieved clinically, and radiographs showed improvement in the interproximal vertical bone defects.

Adult↗