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Y Oba

Publications and source records attributed to Y Oba.

At least 19 recordsLinked to original sources
PubMed2007

Identification of genes related to mechanical stress in human periodontal ligament cells using microarray analysis.

BACKGROUND AND OBJECTIVE: Differential expression of genes in human periodontal ligament (PDL) under mechanical stress, such as orthodontic force, is thought to be involved in the remodeling of PDL cells and periodontal tissues. However, little is known about the genes expressed in PDL cells under mechanical stress. MATERIAL AND METHODS: We employed microarray analysis to assess, in a comprehensive manner, the gene expression profiles in PDL cells compressed by a static force using an in vitro three-dimensional culture system. Six genes were selected and validated by quantitative real-time polymerase chain reaction analysis, consistent with the microarray data. RESULTS: The microarray data revealed that 108 of 30,000 genes tested were differentially expressed by mechanical force loading. Among them, 85 genes were up-regulated by mechanical stress, while 23 genes were down-regulated, judging by the thresholds of a two-fold increase/decrease compared with the controls. Thirty-two of the up-regulated and eight of the down-regulated genes, well-characterized in protein function, were involved in numerous biological processes including cell communication, cell signaling, cell cycle, stress response, and calcium release. However, several genes differentially expressed in our microarray data have not been well defined as stress-response molecules. CONCLUSION: Our microarray is the first to show the gene profile in PDL cells caused by mechanical stress; however, further studies to clarify the physiological function of these molecules in PDL cells are required.

Calcium↗
PubMed2006

Cloning and characterization of the homologous genes of firefly luciferase in the mealworm beetle, Tenebrio molitor.

Three homologous genes of firefly luciferase were cloned from the non-luminous beetle Tenebrio molitor. Three gene products for homologues, TmLL-1, TmLL-2 and TmLL-3, showed fatty acyl-coenzyme A (acyl-CoA) synthetic activity, but not luciferase activity with firefly luciferin. The transcripts were detected through the developmental stages in T. molitor. These results suggested that firefly luciferase was evolved from a fatty acyl-coenzyme A synthetase by gene duplications in the insect.

Amino Acid Sequence↗
PubMed2004

Effects of modification at the fifth residue of mu-conotoxin GIIIA with bulky tags on the electrically stimulated contraction of the rat diaphragm.

Mu-conotoxin GIIIA, a peptide toxin from the cone snail, blocks muscle-type sodium channels. Thr-5 of mu-conotoxin GIIIA, located on the opposite side of the active site in the globular molecule, was replaced by Cys to which the bulky tags were attached. The tagged mu-conotoxin GIIIA derivatives, except for the phospholipid-tagged one, exerted the biological activity with a potency slightly weaker than natural mu-conotoxin GIIIA. When the biotinylated tags of various lengths were added, the presence of avidin suppressed the action of the biotinylated toxins of <4 nm, but not with 5 nm. The bulky biotinylated tags are useful as a caliper to measure the depth of receptor sites in the channels.

Amino Acid Sequence↗
PubMed2001

Modification of Arg-13 of mu-conotoxin GIIIA with piperidinyl-Arg analogs and their relation to the inhibition of sodium channels.

mu-Conotoxin GIIIA, a peptide toxin isolated from the marine snail Conus geographus, preferentially blocks skeletal muscle sodium channels in vertebrates. In this study, analogs of mu-conotoxin GIIIA in which essential Arg-13 was replaced with arginine analogs consisting of a piperidyl framework to regulate length and direction of the side chain were synthesized. Synthesized analogs exhibited similar CD and NMR spectra to that of GIIIA, suggesting a three-dimensional structure identical to that of the native toxin. The biological activities of piperidyl analogs were decreased or lost despite the small change in the side chain of Arg-13. The investigated structure-activity relationships in inhibiting electrically stimulated muscle contraction suggest that the guanidinium group at amino acid position 13 interacts best when spaced with three to four carbons and placed in a vertical direction from the peptide loop. Thus, the position of the guanidinium group at Arg-13 of GIIIA must be located in a certain range for its strong interaction with the channel protein.

Amino Acid Sequence↗
PubMed2001

Macrophage inflammatory protein-1alpha is an osteoclastogenic factor in myeloma that is independent of receptor activator of nuclear factor kappaB ligand.

A complementary DNA expression library derived from marrow samples from myeloma patients was recently screened and human macrophage inflammatory protein-1alpha (hMIP-1alpha) was identified as an osteoclastogenic factor expressed in these samples. hMIP-1alpha enhanced osteoclast (OCL) formation in human marrow cultures and by highly purified OCL precursors in a dose-dependent manner (5-200 pg/mL). Furthermore, hMIP-1alpha enhanced OCL formation induced by human interleukin-6 (IL-6), which is produced by marrow stromal cells when they interact with myeloma cells. hMIP-1alpha also enhanced OCL formation induced by parathyroid hormone-related protein (PTHrP) and receptor activator of nuclear factor kappaB ligand (RANKL), factors also implicated in myeloma bone disease. Time-course studies revealed that the hMIP-1alpha acted during the last 2 weeks of the 3-week culture period. Reverse transcription-polymerase chain reaction analysis showed that the chemokine receptors for hMIP-1alpha (CCR1 and CCR5) were expressed by human bone marrow and highly purified early OCL precursors. Furthermore, hMIP-1alpha did not increase expression of RANKL. These data demonstrate that hMIP-1alpha is an osteoclastogenic factor that appears to act directly on human OCL progenitors and acts at the later stages of OCL differentiation. These data further suggest that in patients with myeloma, MIP-1alpha produced by myeloma cells, in combination with RANKL and IL-6 that are produced by marrow stromal cells in response to myeloma cells, enhances OCL formation through their combined effects on OCL precursors. (Blood. 2001;97:3349-3353)

Bone Marrow Cells↗
PubMed2001

Fish gonadotropin and thyrotropin receptors: the evolution of glycoprotein hormone receptors in vertebrates.

We have cloned and characterized, for the first time in fish, two different gonadotropin receptors (GTHR) and a single thyrotropin receptor (TSHR) from amago salmon (Oncorhynchus rhodurus) and Nile tilapia (Oreochromis niloticus). Phylogenetic analyses and intron/exon structure suggest that the two GTHRs in fish are comparable to tetrapod follicle stimulating hormone and luteinizing hormone receptors. Temporal and spatial expression patterns, examined by Northern blot analysis and in situ hybridization, paralleled those seen in mammals and birds. Consequently, genetic and functional divergence of two GTHRs and TSHR probably occurred before the teleost and tetrapod split.

Animals↗
PubMed2001

Antisense inhibition of macrophage inflammatory protein 1-alpha blocks bone destruction in a model of myeloma bone disease.

We recently identified macrophage inflammatory protein 1-alpha (MIP-1alpha) as a factor produced by multiple myeloma (MM) cells that may be responsible for the bone destruction in MM (1). To investigate the role of MIP-1alpha in MM bone disease in vivo, the human MM-derived cell line ARH was stably transfected with an antisense construct to MIP-1alpha (AS-ARH) and tested for its capacity to induce MM bone disease in SCID mice. Human MIP-1alpha levels in marrow plasma from AS-ARH mice were markedly decreased compared with controls treated with ARH cells transfected with empty vector (EV-ARH). Mice treated with AS-ARH cells lived longer than controls and, unlike the controls, they showed no radiologically identifiable lytic lesions. Histomorphometric analysis demonstrated that osteoclasts (OCLs) per square millimeter of bone and OCLs per millimeter of bone surface of AS-ARH mice were significantly less than in EV-ARH mice, and the percentage of tumors per total bone area was also significantly decreased. AS-ARH cells demonstrated decreased adherence to marrow stromal cells, due to reduced expression of the alpha(5)beta(1) integrin and diminished homing capacity and survival. These data support an important role for MIP-1alpha in cell homing, survival, and bone destruction in MM.

Animals↗
PubMed2001

Osteoclast inhibitory peptide 2 inhibits osteoclast formation via its C-terminal fragment.

Osteoclast inhibitory peptide 2 (OIP-2) is a novel autocrine/paracrine factor produced by osteoclasts (OCLs) that inhibits bone resorption and OCL formation in vitro and in vivo. It is identical to the asparaginyl endopeptidase legumain. During maturation of OIP-2, a signal peptide and a 17-kDa C-terminal fragment (CTF) are cleaved to produce the mature enzyme. To determine if enzyme activity is required for inhibition of OCL formation or if only the CTF is responsible for these effects, we synthesized His-tagged complementary DNA (cDNA) constructs for the CTF of OIP-2, the proform of OIP-2, and the "mature enzyme" form of OIP-2. The proform or the CTF portion of OIP-2 inhibited OCL formation in a dose-dependent manner in murine bone marrow cultures stimulated with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. The mature form of OIP-2, which was enzymatically active, did not inhibit OCL formation. In addition, OIP-2 inhibited OCL formation in cultures of highly purified human OCL precursor cells or RAW264.7 cells stimulated with 10 ng/ml of receptor activator of NF-kappaB (RANK) ligand. Binding studies with His-tagged OIP-2 showed expression of a putative OIP-2 receptor on RAW264.7 cells treated with RANK ligand for 4 days and human marrow cultures treated with 1,25(OH)2D3 for 3 weeks. These data show that the CTF of OIP-2, rather than the mature enzyme, mediates the inhibitory effects of OIP-2 through a putative receptor on OCL precursors.

Animals↗
PubMed2000

Cloning, functional characterization, and expression of thyrotropin receptors in the thyroid of amago salmon (Oncorhynchus rhodurus).

Two thyrotropin receptor cDNAs (sTSH-Ra and sTSH-Rb) were cloned from thyroid tissue of the amago salmon, Oncorhynchus rhodurus. sTSH-Ra and sTSH-Rb showed the highest degrees of sequence homology to mammalian TSH receptors. Functional characterization in COS-7 cells transiently transfected with sTSH-Ra or sTSH-Rb showed the largest increase in cAMP when exposed to bovine TSH. RT-PCR analysis demonstrated that sTSH-Ra and sTSH-Rb were expressed in the basibranchial region, but not in the ovary, testis, liver, kidney or brain. In situ hybridization revealed that sTSH-Ra and sTSH-Rb were exclusively expressed in thyroid follicular epithelial cells of amago salmon undergoing smoltification. These results indicated that the cloned cDNAs encode functional TSH receptor proteins. This is the first report of isolation of TSH receptor molecules from nonmammalian vertebrates.

Amino Acid Sequence↗
PubMed2000

Molecular cloning, functional characterization, and gene expression of a follicle-stimulating hormone receptor in the testis of newt Cynops pyrrhogaster.

We previously demonstrated in vitro that mammalian follicle-stimulating hormone (FSH) stimulates the proliferation of newt secondary spermatogonia and their differentiation into primary spermatocytes. In the current study, we isolated a cDNA from newt testis that encodes a FSH receptor (FSH-R). The total sequence homology in the deduced protein of the newt was approximately 70% with mammalian FSH-Rs. Mammalian cells, transiently transfected with the cloned newt FSH-R cDNA, displayed specific binding to [(125)I] human FSH and cAMP accumulation, indicating that the cloned cDNA encodes a functional newt FSH-R protein. Northern blot analysis revealed a single transcript of approximately 3.0 kb length that was synthesized in testicular somatic cells (mainly Sertoli cells) from spermatogonial to spermatid stages with the highest level expressed during the primary spermatocytes stage. These results demonstrate that FSH stimulates newt spermatogenesis through the FSH-R. This study, as far as we know, reports for the first time the cloning of an amphibian FSH-R cDNA.

Amino Acid Sequence↗
PubMed2000

Identification and cDNA cloning of alveolin, an extracellular metalloproteinase, which induces chorion hardening of medaka (Oryzias latipes) eggs upon fertilization.

Chorion hardening is triggered by the contents of cortical alveoli that are released upon fertilization of medaka (Oryzias latipes) eggs. We purified the chorion hardening-inducing activity as a single protein from the exudate of cortical alveoli of medaka eggs. This activity was co-purified with proteolytic activity of the chorion protein ZI-1,2. Based on the amino acid sequence of purified protein, we cloned the cDNA of this protein from a medaka ovarian cDNA library. Sequence analyses revealed typical sequence features, a zinc-binding motif and a methionine turn motif, of the astacin metalloproteinase family. We termed this protein "alveolin." Alveolin has a molecular mass of 21.5 kDa deduced by the amino acid sequence and neutral optimal pH range. Alveolin hydrolyzes ZI-1,2. Alveolin activity was strongly inhibited by metal-chelating agents but not by various proteinase inhibitors. To our knowledge, this is the first description of the isolation and identification of the chorion hardening-inducing factor from cortical alveoli exudate of teleost eggs.

Amino Acid Sequence↗
PubMed2000

[beta-thalassemia minor diagnosed in a patient with chronic myelogenous leukemia during hydroxyurea therapy].

A 55-year-old man was admitted to our hospital because of leukocytosis and microcytic anemia with hypochromia, target cells, and increased levels of hemoglobin A2 and hemoglobin F. The results of a gene analysis yielded a diagnosis of chronic myelogenous leukemia and beta-thalassemia minor. A gradual increase in hemoglobin was observed during hydroxyurea therapy, which was performed over a 12-week period. This increment appeared to be due to suppressed production of myeloid cells. It was been reported that hydroxyurea increases total hemoglobin due to increased hemoglobin F synthesis in patients with beta-thalassemia. However, hydroxyurea had no clear influence on hemoglobin concentration in this case.

Antineoplastic Agents↗
PubMed2000

Reevaluation of continuous oxygen therapy after initial prescription in patients with chronic obstructive pulmonary disease.

BACKGROUND: Long-term oxygen therapy improves survival and quality of life in hypoxemic patients with chronic obstructive pulmonary disease (COPD). The need for long-term oxygen therapy should be determined when patients are medically stable. The Third Oxygen Consensus Conference recommended reevaluating patients 1-3 months after continuous oxygen therapy (COT) is initiated, if initiated when the patient is medically unstable. METHODS: A cross-sectional study was performed to examine how often orders for COT are reevaluated pursuant to the guidelines promulgated by the Third Oxygen Therapy Consensus Conference, and to assess the impact that following these guidelines would have on the cost of COT. RESULTS: Of 226 patients prescribed home oxygen therapy, 92 had COPD as a primary diagnosis and 57 were prescribed COT. Only 19 (35%) of 55 patients who returned to the clinics were appropriately reevaluated. The rate of appropriate reevaluation was significantly higher among pulmonary physicians than among primary care physicians (65% vs 17%; odds ratio: 9.0; 95% confidence interval: 2.5-32). Of 19 patients who were appropriately reevaluated, 11 (58%) were discontinued from COT. The patients who were discontinued from COT had a significantly higher percent of predicted forced expiratory volume in the first second than those who were not (34 +/- 8.6% vs 25 +/- 8.8%; p = 0.04). CONCLUSIONS: In our study, most patients were clinically unstable when COT was prescribed, and a significant number of patients remained on COT without reevaluation. Up to 60% of those patients could potentially be discontinued from COT if appropriately reevaluated. Referring a patient initiated on COT to a pulmonary specialist for the proper use of oxygen is strongly recommended. Reevaluating such patients in a timely fashion and discontinuing unnecessary oxygen concentrators could possibly save $106-153 million per year in the United States.

Aged↗
PubMed1999

The duality of fish gonadotropin receptors: cloning and functional characterization of a second gonadotropin receptor cDNA expressed in the ovary and testis of amago salmon (Oncorhynchus rhodurus).

We previously isolated a cDNA encoding a gonadotropin receptor (sGTH-R) from amago salmon (Oncorhynchus rhodurus) ovarian follicles. In the present study, we cloned a second gonadotropin receptor (sGTH-RI) from the same RNA preparations. Overall sequence homology between sGTH-RI and sGTH-R is 44%. The highest homology occurs with mammalian FSH receptors (49%). Functional characterization examined in COS-7 cells transiently transfected with sGTH-RI showed the largest increase in cAMP production when exposed to salmon GTH I. These results provide the first evidence in any ectothermic vertebrate, the amago salmon, of the duality of gonadotropin receptors.

Amino Acid Sequence↗
PubMed1999

Cloning, functional characterization, and expression of a gonadotropin receptor cDNA in the ovary and testis of amago salmon (Oncorhynchus rhodurus).

A gonadotropin receptor was cloned from amago salmon (Oncorhynchus rhodurus) ovarian follicles. This receptor (sGTH-R) belongs to the glycoprotein hormone receptor family with a large extracellular and seven-transmembrane domains. Its sequence homology is highest with mammalian LH receptors. Phylogenetic analysis reveals that sGTH-R is grouped with mammalian and chicken FSH and LH receptors, but not with mammalian TSH receptors. sGTH-R is expressed dominantly in the ovary and testis. Functional characterization examined with transiently transfected mammalian cells revealed increased intracellular cAMP level when exposed to mammalian and fish gonadotropins; the most potent hormone was salmon GTH II. These results indicate that the cloned cDNA encodes a functional amago salmon GTH receptor protein.

Amino Acid Sequence↗
PubMed1999

Medaka (Oryzias latipes) FTZ-F1 potentially regulates the transcription of P-450 aromatase in ovarian follicles: cDNA cloning and functional characterization.

Our previous findings suggest the activity of cytochrome P-450 aromatase (P-450arom), the enzyme which converts testosterone to estradiol-17beta, in the ovarian follicle of medaka (Oryzias latipes) is regulated at the transcriptional level. In this study, we cloned a cDNA encoding a FTZ-F1-like protein (mdFtz-F1) from ovarian follicles of medaka. In vitro translated mdFTZ-F1, and nuclear extract from medaka ovarian follicles, formed complexes with oligonucleotide probes containing putative orphan nuclear receptor binding motifs, which are present in the promoter region of the medaka P-450arom gene. The expression pattern of mdFtz-F1 transcripts during oogenesis coincides with that of P-450arom transcripts. Transfection assays further suggest a potential transcriptional regulatory activity of mdFTZ-F1 upon the medaka P-450arom promoter. Taken together, these results suggest a potential role of mdFTZ-F1 in the transcriptional regulation of P-450arom in the ovarian follicle of medaka.

Amino Acid Sequence↗