Biomedical subjects

Takahiro Nakamura

Publications and source records attributed to Takahiro Nakamura.

At least 19 recordsLinked to original sources

PubMed2007

A functional SNP in ITIH3 is associated with susceptibility to myocardial infarction.

Myocardial infarction (MI) results from complex interactions of multiple genetic and environmental factors. To disclose genetic backgrounds of MI, we performed a large-scale, case-control association study using 52,608 gene-based single-nucleotide polymorphism (SNP) markers, and identified a candidate SNP located on chromosome 3p21.2-p21.1. Subsequent linkage-disequilibrium mapping indicated very significant association between MI and a SNP in exon 2 of the inter-alpha (globulin) inhibitor 3 gene (ITIH3; chi(2) = 24.88, P = 6.1 x 10(-7), 3,353 affected individuals versus 3,807 controls). In vitro functional analyses showed that this SNP enhanced the transcriptional level of the ITIH3 gene. Furthermore, we found expression of the ITIH3 protein in the vascular smooth muscle cells and macrophages in the human atherosclerotic lesions, suggesting ITIH3 SNP to be a novel genetic risk factor of MI.

Alpha-Globulins↗

PubMed2007

Functional single-nucleotide polymorphisms in the secretogranin III (SCG3) gene that form secretory granules with appetite-related neuropeptides are associated with obesity.

CONTEXT: Genetic factors are important for the development of obesity. However, the genetic background of obesity still remains unclear. OBJECTIVE: Our objective was to search for obesity-related genes using a large number of gene-based single-nucleotide polymorphisms (SNPs). DESIGN AND SETTING: We conducted case-control association analyses using 94 obese patients and 658 controls with 62,663 SNPs selected from the SNP database. SNPs that possessed P < or = 0.02 were further analyzed using 796 obese and 711 control subjects. One SNP (rs3764220) in the secretogranin III (SCG3) gene showed the lowest P value (P = 0.0000019). We sequenced an approximately 300-kb genomic region around rs3764220 and discovered SNPs for haplotype analyses. SCG3 was the only gene within a haplotype block that contained rs3764220. The functions of SCG3 were studied. PATIENTS: Obese subjects (body mass index > or = 30 kg/m(2), n = 890) and control subjects (general population; n = 658, body mass index < or = 25 kg/m(2); n = 711) were recruited for this study. RESULTS: Twelve SNPs in the SCG3 gene including rs3764220 were in almost complete linkage disequilibrium and significantly associated with an obesity phenotype. Two SNPs (rs16964465, rs16964476) affected the transcriptional activity of SCG3, and subjects with the minor allele seemed to be resistant to obesity (odds ratio, 9.23; 95% confidence interval, 2.77-30.80; chi(2) = 19.2; P = 0.0000067). SCG3 mRNA and immunoreactivity were detected in the paraventricular nucleus, lateral hypothalamic area, and arcuate nucleus, and the protein coexisted with orexin, melanin-concentrating hormone, neuropeptide Y, and proopiomelanocortin. SCG3 formed a granule-like structure together with these neuropeptides. CONCLUSIONS: Genetic variations in the SCG3 gene may influence the risk of obesity through possible regulation of hypothalamic neuropeptide secretion.

Adult↗

PubMed2006

Efficacy profile of bucillamine in rheumatoid arthritis patients in a large observational cohort study, IORRA.

Bucillamine (Buc) is a disease-modifying antirheumatic drug (DMARD) developed in Japan, which has been used as one of the first-line DMARDs for the treatment of rheumatoid arthritis (RA) in Japan. However, direct comparison of this drug with standard DMARDs including sulfasalazine (SASP) and methotrexate (MTX) has been scarcely reported. We therefore tried to evaluate the clinical efficacy of Buc by analyzing the database from the long-term observational cohort study IORRA (previously known as J-ARAMIS). The cross-sectional analysis revealed that responses to Buc treatment were better in males, patients with shorter duration of illness, and those who were rheumatoid factor-negative. In the longitudinal analysis, although there was no marked difference among the baseline variables of patients with Buc, SASP, and MTX, the percentage of patients exhibiting moderate or good response to treatment, as rated using the European League Against Rheumatism improvement criteria, was higher in the Buc group (41.0%) than in the MTX (32.6%) and SASP groups (25.6%). These data support Buc as a candidate for being a first-line drug for the treatment of patients with RA.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2006

Identification of human oral keratinocyte stem/progenitor cells by neurotrophin receptor p75 and the role of neurotrophin/p75 signaling.

This study was undertaken to determine whether human oral keratinocyte stem cells characteristically express higher levels of the low-affinity neurotrophin receptor p75 and to elucidate the function of p75 in oral keratinocytes. Examination of their expression patterns and cell-cycling status in vivo showed that p75 was exclusively expressed in the basal cell layer of both the tips of the papillae and the deep rete ridges. These immunostaining patterns suggest a cluster organization; most p75(+) cells did not actively cycle in vivo. Cell sorting showed that cells in the p75(+) subset were smaller and possessed higher in vitro proliferative capacity and clonal growth potential than the p75(-) subset. Clonal analysis revealed that holoclone-type (stem cell compartment), meroclone-type (intermediate compartment), and paraclone-type (transient amplifying cell compartment) cells, previously identified in skin and the ocular surface, were present in human oral mucosal epithelium. Holoclone-type cells showed stronger p75 expression at both the mRNA and protein level than did meroclone- and paraclone-type cells. Among the several neurotrophins, nerve growth factor (NGF) and neurotrophin-3 stimulated p75(+) oral keratinocyte cell proliferation, and only NGF protected them from apoptosis. Our in vivo and in vitro findings indicate that p75 is a potential marker of oral keratinocyte stem/progenitor cells and that some neurotrophin/p75 signaling affects cell growth and survival.

Apoptosis↗

PubMed2006

A pentatricopeptide repeat protein is a site recognition factor in chloroplast RNA editing.

In higher plants, RNA editing is a post-transcriptional process that converts C to U in organelle mRNAs. We have previously shown that an Arabidopsis thaliana crr4 mutant is defective with respect to RNA editing for creating the translational initial codon of the plastid ndhD gene (the ndhD-1 site). CRR4 contains 11 pentatricopeptide repeat motifs but does not contain any domains that are likely to be involved in the editing activity. The green fluorescent protein fused to the putative transit peptide of CRR4 targeted the plastid. The recombinant CRR4 expressed in Escherichia coli specifically bound to the 25 nucleotides of the upstream and the 10 nucleotides of the downstream sequences surrounding the editing site of ndhD-1. The target C nucleotide of this editing is not essential for the binding of CRR4. Taken together with the genetic evidence, we conclude that the pentatricopeptide repeat protein CRR4 is a sequence-specific RNA-binding protein that acts as a site recognition factor in plastid RNA editing.

Arabidopsis↗

PubMed2006

Replication of the association of the aspartic acid repeat polymorphism in the asporin gene with knee-osteoarthritis susceptibility in Han Chinese.

A genetic association of osteoarthritis (OA) and functional polymorphisms in the aspartic acid (D) repeat of the asporin gene was reported in Japanese and European Caucasians; however, the results were controversial. Our objective was to evaluate whether the D repeat polymorphism was associated with knee OA in Han Chinese. The D repeat polymorphism was genotyped in 218 patients who suffered from primary symptomatic knee OA with radiographic confirmation and in 454 age-matched controls, and the allelic association of the repeat was examined. Frequencies of the D13 and D14 alleles were similar to those of Japanese, but different from those of European Caucasians. The D14 allele was significantly over-represented in knee OA patients (P=0.0013; odds ratio 2.04; 95% confidence interval 1.32-3.15). D14 was more frequent in early-onset patients than in late-onset patients (P=0.043) and the age at onset in patients with D14 was earlier (P=0.028; log-rank test). Thus, the association of the D14 allele with knee OA susceptibility was replicated in Han Chinese. This was the first instance that association of the OA susceptibility gene was definitely replicated between different ethnic groups.

Adult↗

PubMed2006

Ocular surface reconstruction with combination of cultivated autologous oral mucosal epithelial transplantation and penetrating keratoplasty.

PURPOSE: To report an assessment of the two-step surgical combination of cultivated autologous oral mucosal epithelial transplantation (COMET) and penetrating keratoplasty (PKP) used to treat patients with severe limbal deficiency disorders, and to investigate the keratin expression patterns of transplanted surviving oral mucosal epithelium. DESIGN: Observational case series. METHODS: Two patients with Stevens-Johnson syndrome and chemical eye injury were treated by COMET followed, approximately six months later, by a PKP triple procedure. In the course of a mean follow-up period of 22.5 months, their clinical outcomes and the efficacy of this two-step surgical procedure were assessed. In addition, the keratin expression in corneal buttons excised during PKP were immunohistochemically examined to characterize the oral mucosal epithelium that survived ectopically on the cornea. In vivo laser confocal microscopy was used to investigate the structure of the epithelium on the corneal grafts. RESULTS: The ocular surfaces were successfully reconstructed with cultivated autologous oral mucosal epithelial sheets and PKP. No clinical complications, such as persistent epithelial defects, rejections, or recurrence of cicatrization, were encountered. Postoperative best-corrected visual acuity was 20/125 in one patient and 20/100 in the other. The surviving oral mucosal epithelium, distinguished by its fluorescence pattern, consisted of an irregular, nonkeratinized, stratified epithelium without goblet cells. Immunohistochemical study demonstrated that K3, but not K12, was expressed in the transplanted cultivated oral mucosal epithelium that was similar to oral mucosal tissue. In vivo, the epithelial structure and cell density in the basal cell layer of the corneal grafts were similar to normal cornea. CONCLUSIONS: This study presents a two-step surgical approach to treat severely scarred ocular surfaces by means of a combination of COMET and PKP. Clinical outcomes suggest that this treatment may be beneficial for the maintenance of the reconstructed ocular surface by providing oral mucosal epithelium around the corneal graft.

Aged↗

PubMed2006

Fission yeast MAP kinase is required for the increased securin-separase interaction that rescues separase mutants under stresses.

Sister chromatid separation requires two steps of proteolysis. Securin, the chaperon and inhibitor of separase, is destructed in anaphase after polyubiquitination, and resulting activated separase cleaves the cohesin subunit Scc1/Rad21. Fission yeast securin/Cut2 and separase/Cut1 that form the complex are essential for viability and a number of temperature-sensitive (ts) mutants have been isolated. We here report that the stresses such as 1.2 M sorbitol, 0.6 M KCl and 0.1 M CaCl(2) in the medium suppress the ts phenotypes of all the cut1 mutants and two of the three cut2 mutants examined. This unexpected finding led us to study how the ts phenotypes of cut1 and cut2 mutants were rescued by the increased stresses. The stresses caused a temporal arrest in the cell number increase, and this arrest was dependent on Spc1/Sty1 but not Rad3 and Mad2. During the 2-3 hr arrested period that occurred prior to the restart of division cycle, the level of securin dramatically increased, apparently accompanying the increased complex formation with mutant separase protein. Securin bound to separase was hyperphosphorylated. The stresses could not rescue the indestructible Cut2 and Rad21 mutants. We postulate that the stresses produce the hyperchaperonic form of Cut2 that can rescue separase mutations.

Calcium Chloride↗

PubMed2006

Transplantation of autologous serum-derived cultivated corneal epithelial equivalents for the treatment of severe ocular surface disease.

PURPOSE: To evaluate the use of autologous serum (AS)-derived cultivated corneal epithelial transplantation for the treatment of severe ocular surface disease. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Nine eyes from 9 patients with total limbal stem cell deficiency were studied. These consisted of 2 eyes with Stevens-Johnson syndrome, 1 with chemical injury, 1 with ocular cicatricial pemphigoid, 1 with Salzmann corneal dystrophy, 1 with aniridia, 1 with graft-versus-host disease, and 2 with idiopathic ocular surface disease. METHODS: Autologous serum obtained from patients was used for cultivating corneal epithelial cells on an amniotic membrane substrate. These AS-derived corneal epithelial equivalents were compared with those derived from fetal bovine serum (FBS)-supplemented medium. At the time of surgery, complete removal of the corneal pannus and conjunctiva up to 3 mm from the limbus was performed. Allogeneic (7 cases) and autologous (2 cases) AS-derived cultivated corneal epithelial equivalents were transplanted onto the ocular surface. Postoperative follow-up included serial slit-lamp examinations with fluorescein staining, as well as photographic documentation. MAIN OUTCOME MEASURES: Ocular surface reconstruction with corneal epithelialization, graft integrity, visual acuity, and postoperative complications. RESULTS: The corneal epithelial sheets cultivated in AS- and FBS-supplemented media were morphologically similar, and demonstrated the normal expression of tissue-specific keratins and junctional specialization assembly proteins. After transplantation, complete corneal epithelialization was achieved within 2 to 5 days. All eyes demonstrated an improvement in visual acuity by > or =2 lines. During the follow-up period of 14.6+/-4.36 months, the corneal surface of all patients remained stable and transparent, without significant complications. CONCLUSIONS: Transplantation of AS-derived cultivated corneal epithelial equivalents was shown to be a feasible method of treating patients with severe ocular surface disease. The use of AS is of clinical importance in the development of autologous xenobiotic-free bioengineered ocular surface equivalents for clinical transplantation.

Adult↗

PubMed2006

A functional SNP in PSMA6 confers risk of myocardial infarction in the Japanese population.

Inflammation is now considered critical in the pathogenesis of myocardial infarction. One of the mechanisms regulating the inflammatory process is the ubiquitin-proteasome system. We investigated whether variants of the 20S proteasome are associated with susceptibility to myocardial infarction and found a common SNP (minor allele frequency of 0.35) in the proteasome subunit alpha type 6 gene (PSMA6) conferring risk of myocardial infarction in the Japanese population (chi(2) = 21.1, P = 0.0000044, 2,592 affected individuals versus 2,851 controls). We replicated this association in another panel of myocardial infarction and control subjects, although its relevance to other ethnic groups remains to be clarified. The SNP, located in the 5' untranslated region of exon 1 in this gene, enhanced the transcription of PSMA6. Moreover, suppression of PSMA6 expression using short interfering RNA in cultured cells reduced activation of the transcription factor NF-kappaB by stabilizing phosphorylated IkappaB. Our results implicate this PSMA6 SNP as a previously unknown genetic risk factor for myocardial infarction.

Alleles↗

PubMed2006

Neural conversion of ES cells by an inductive activity on human amniotic membrane matrix.

Here we report a human-derived material with potent inductive activity that selectively converts ES cells into neural tissues. Both mouse and human ES cells efficiently differentiate into neural precursors when cultured on the matrix components of the human amniotic membrane in serum-free medium [amniotic membrane matrix-based ES cell differentiation (AMED)]. AMED-induced neural tissues have regional characteristics (brainstem) similar to those induced by coculture with mouse PA6 stromal cells [a common method called stromal cell-derived inducing activity (SDIA) culture]. Like the SDIA culture, the AMED system is applicable to the in vitro generation of various CNS tissues, including dopaminergic neurons, motor neurons, and retinal pigment epithelium. In contrast to the SDIA method, which uses animal cells, the AMED culture uses a noncellular inductive material derived from an easily available human tissue; therefore, AMED should provide a more suitable and versatile system for generating a variety of neural tissues for clinical applications.

Amnion↗

PubMed2006

Different expression of angiogenesis-related factors between human cultivated corneal and oral epithelial sheets.

We developed a cultivated oral mucosal epithelial sheet (COE) transplantation system to address severe human ocular surface disorders. Unlike the cultivated corneal epithelial sheet (CCE), the COE induces mild superficial peripheral neovascularization although central clarity is maintained. To evaluate the characteristic differences between CCE and COE regarding to angiogenesis, we examined the expression of angiogenesis-related factors in CCE and COE. Using samples of CCE and COE, we immunohistochemically determined protein expression of the angiogenesis related factors: Thrombospondin-1 (TSP-1), pigment epithelium derived factor (PEDF), endostatin, angiostatin, vascular endothelial growth factor (VEGF), Fms-like tyrosine kinase 1 (Flt-1), kinase insert domain receptor (KDR), and basic fibroblast growth factor (bFGF). We used Western blot analysis to confirm the factors that were immunohistochemically different in CCE and COE. The immunohistochemical staining intensity of TSP-1 was higher in CCE than COE and by Western blot analysis the expression of TSP-1 was significantly higher in CCE than COE (P<0.05). PEDF and endostatin stained moderately stronger in CCE than COE. Immunohistochemically there was no obvious difference between CCE and COE with respect to angiostatin, VEGF, Flt-1, KDR, and bFGF. In comparison with CCE, COE showed decreased expression of anti-angiogenic factors particularly TSP-1. This different expression may relate to the superficial peripheral neovascularization encountered after COE transplantation.

Angiogenesis Inducing Agents↗

PubMed2006

Histone H2B mutations in inner region affect ubiquitination, centromere function, silencing and chromosome segregation.

The reiterated nature of histone genes has hampered genetic approach to dissect the role of histones in chromatin dynamics. We here report isolation of three temperature-sensitive (ts) Schizosaccharomyces pombe strains, containing amino-acid substitutions in the sole histone H2B gene (htb1+). The mutation sites reside in the highly conserved, non-helical residues of H2B, which are implicated in DNA-protein or protein-protein interactions in the nucleosome. In the allele of htb1-72, the substitution (G52D) occurs at the DNA binding loop L1, causing disruption of the gene silencing in heterochromatic regions and lagging chromosomes in anaphase. In another allele htb1-223 (P102L) locating in the junction between alpha3 and alphaC, the mutant residue is in contact with H2A and other histones, leading to structural aberrations in the central centromere chromatin and unequal chromosome segregation in anaphase. The third allele htb1-442 (E34K) near alpha1 displayed little defect. Evidence is provided that monoubiquitinated H2B is greatly unstable in P102L mutant, possibly owing to proteasome-independent destruction or enhanced deubiquitination. Histone H2B thus plays an important role in centromere/kinetochore formation.

Amino Acid Sequence↗

PubMed2006

Autologous serum-derived cultivated oral epithelial transplants for severe ocular surface disease.

OBJECTIVE: To evaluate the use of autologous serum (AS)-derived cultivated oral epithelial transplants for the treatment of severe ocular surface disease. METHODS: We used AS from 10 patients with severe ocular surface disease and total limbal stem cell deficiency to develop autologous cultivated oral epithelial equivalents. These were compared with epithelial equivalents derived from conventional fetal bovine serum-supplemented medium. Surgery involved removal of the corneal pannus and surrounding diseased tissue and transplantation of the AS-derived epithelial equivalents. The oral equivalents were analyzed by review of histologic and immunohistochemical findings. RESULTS: Oral epithelial sheets cultivated in AS- and fetal bovine serum-supplemented media were similar in morphology, and both formed basement membrane assembly proteins important for maintaining graft integrity. Complete corneal epithelialization was achieved within 2 to 5 days postoperatively. The ocular surface remained stable without major complications in all eyes during a mean +/- SD follow-up of 12.6 +/- 3.9 months. The visual acuity improved by more than 2 lines in 9 of 10 eyes, with transplanted oral epithelium surviving up to 19 months. CONCLUSION: The successful use of an AS-derived oral epithelial equivalent to treat severe ocular surface disease represents an important advance in the pursuit of completely autologous xenobiotic-free bioengineered ocular equivalents for clinical transplantation.

Adult↗

PubMed2006

The persistence of transplanted amniotic membrane in corneal stroma.

PURPOSE: To characterize the long-term incorporation of transplanted amniotic membrane into corneal stroma. DESIGN: Experimental study. METHODS: Rabbit amniotic membrane, stained with a fluorescent dye (DTAF), was implanted unilaterally into the corneal stroma of four adult rabbits. Corneas were examined clinically and by transmission electron microscopy and fluorescent microscopy at 1, 3, 7, and 10 months after surgery. RESULTS: Visibility of the transplanted amniotic membrane, in situ, on slit-lamp examination decreased over time. However, fluorescent and electron microscopy clearly demonstrated that the amniotic membrane remained structurally unchanged and intact within the corneal stroma up to 10 months after implantation. CONCLUSIONS: Amniotic membrane allografts persist intact within an intracorneal space for many months postoperatively and are not quickly broken down or dissolved by the host tissue.

Amnion↗

PubMed2006

Midterm results on ocular surface reconstruction using cultivated autologous oral mucosal epithelial transplantation.

PURPOSE: To perform a midterm assessment of the integrity and reproducibility of cultivated autologous oral mucosal epithelial sheets, and to evaluate the clinical efficacy of their transplantation in ocular surface. DESIGN: Observational case series. METHODS: Cultivated autologous oral mucosal epithelial sheets were created using amniotic membrane and buccal mucosal epithelium from 12 patients with Stevens-Johnson syndrome, chemical and thermal injury, pseudo-ocular cicatricial pemphigoid, and idiopathic ocular surface disorder. They were transplanted onto 15 eyes from these patients who were then followed up for a mean of 20 months; with the longest follow-up being 34 months. We assessed their clinical outcomes with special reference to neovascularization. RESULTS: Cultivated autologous oral mucosal epithelial sheets could be generated from all patients. On the second postoperative day, 14 of 15 sheets transplanted demonstrated total re-epithelialization on the cornea. During the follow-up, the ocular surface was stable and transparent without any major complications in 10 of 15 eyes (67%), and the transplanted epithelium survived for at least 34 months. There were five eyes (33%) with small but long-standing epithelial defects, three of these healed spontaneously, and two (13%) required reoperation. In 10 eyes, postoperative visual acuity was improved by more than 2 lines. All eyes manifested some peripheral corneal vascularization. CONCLUSIONS: We established a successful tissue-engineering technique to generate cultivated autologous oral mucosal epithelial sheets and succeeded in reconstructing the ocular surface. We suggest that this surgical modality may be both safe and useful, especially in younger patients with the most severe ocular surface disorders.

Adolescent↗

PubMed2006

Novel clinical application of sterilized, freeze-dried amniotic membrane to treat patients with pterygium.

PURPOSE: To evaluate the use of sterilized, freeze-dried amniotic membrane (FD-AM) transplantation for pterygium surgery. METHODS: This study involved a prospective, non-comparative, interventional case series. Thirteen eyes of 13 patients with primary (eight eyes) or recurrent (five eyes) pterygium were studied. After excision of the pterygium fibrous tissues and application of intraoperative use of mitomycin-C, sterilized FD-AM was sutured over the bare scleral defect. The integrity of the FD-AM graft, epithelialization over the FD-AM, pterygium recurrence and postoperative complications were evaluated. RESULTS: Postoperatively, the FD-AM was well retained in all patients, and complete epithelialization over the transplanted membrane was achieved within 1-2 weeks. All patients demonstrated early resolution of ocular inflammation and there was no recurrence of pterygium in any of the treated patients during the mean follow-up of 13.9 +/- 6.0 months. No ocular complications were noted following transplantation. CONCLUSION: Sterilized FD-AM showed excellent biocompatibility on the human ocular surface. This novel and promising biomaterial may be a useful alternative to conjunctival grafting in the treatment of pterygium.

Adult↗

PubMed2006

The use of autologous serum in the development of corneal and oral epithelial equivalents in patients with Stevens-Johnson syndrome.

PURPOSE: To evaluate the use of autologous serum (AS) from patients with severe ocular surface disease (OSD) in the development of transplantable corneal and oral epithelial tissue equivalents and to compare it with the use of conventional culture methods by using fetal bovine serum (FBS). METHODS: AS was obtained from patients with severe OSD secondary to Stevens-Johnson syndrome. Corneal and oral epithelial cells were cultivated in medium supplemented with either AS or FBS. Corneal and oral epithelial equivalents were constructed on denuded amniotic membranes. The bromodeoxyuridine (BrdU) ELISA cell proliferation assay and colony-forming efficiency (CFE) of cells cultivated in AS- or FBS-supplemented media were compared. The morphologic characteristics and the basement membrane assembly of cultivated epithelial equivalents were analyzed by light and electron microscopy, as well as by immunohistochemistry. RESULTS: BrdU proliferation assay and CFE analysis showed that human corneal and oral epithelial cells cultivated in AS-supplemented media had comparable proliferative capacities compared with FBS-supplemented media. The corneal and oral epithelial equivalents cultivated in AS- and FBS-supplemented media were morphologically similar and demonstrated the normal expression of tissue-specific keratins and basement membrane assembly. The presence of a well-formed stratified epithelium, a basement membrane, and hemidesmosomal attachments was confirmed by electron microscopy. CONCLUSIONS: AS-supplemented cultures were effective in supporting the proliferation of human corneal and oral epithelial cells, as well as the development of transplantable epithelial equivalents. The use of AS is of clinical importance in the development of autologous xenobiotic-free bioengineered ocular surface equivalents for clinical transplantation.

Adult↗