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Y Ohta

Publications and source records attributed to Y Ohta.

At least 361 records · Page 20Linked to original sources
PubMed1996

Measurement of plasma annexin V by ELISA in the early detection of acute myocardial infarction.

Annexin V is a calcium binding protein which is widely present in various cells and tissues. Using annexin V which we isolated and purified from human cardiac muscle, we prepared an anti-human cardiac annexin V monoclonal antibody. Identification of annexin V was made by means of partial amino acid sequences. An enzyme-linked immunosorbent assay (ELISA) was developed using this monoclonal antibody and anti-canine cardiac annexin V polyclonal antibody. With this ELISA, plasma annexin V concentration was measured in 196 normal healthy individuals, 23 acute myocardial infarction (AMI) patients who were hospitalized within 6 h after the onset of chest pain, and 130 patients with other diseases, including lung, liver and kidney disease. The plasma annexin V concentration in normal healthy individuals was 1.7 +/- 0.6 ng/ml (mean +/- S.D.), while that in AMI patients was elevated to 13.2 +/- 6.8 ng/ml (P < 0.0001) at the time of initial blood drawing, 3.2 +/- 1.5 h after onset of pain, and these values were higher than normal in 21 out of 23 cases (91.3%) of AMI. In all cases excepting 3, annexin V concentration immediately decreased after the onset of pain. The annexin V concentration in patients with old myocardial infarction, chest pain syndrome, valvular heart disease, lung disease and kidney disease was 1.8 +/- 0.8, 2.0 +/- 0.7, 1.7 +/- 1.1, 2.3 +/- 1.4 and 2.1 +/- 1.2 ng/ml, respectively, being within normal limits. The values in liver disease patients and trauma patients were 3.7 +/- 2.7 (P < 0.05) and 3.3 +/- 2.4 (P < 0.05) ng/ml, respectively, being slightly higher than that in normal healthy individuals.

Adult↗
PubMed1996

Molecular cloning and identification of N-acyl-D-glucosamine 2-epimerase from porcine kidney as a renin-binding protein.

N-Acetylneuraminic acid (NeuAc) is an important molecule in biological recognition systems. NeuAc is known to be biosynthesized either from UDP-N-acetyl-D-glucosamine by an action of UDP-N-acetyl-D-glucosamine 2-epimerase or from N-acetyl-D-glucosamine by N-acyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase). However, the physiological function of the GlcNAc 2-epimerase in NeuAc biosynthesis has not been fully evaluated. To clarify the role of GlcNAc 2-epimerase in NeuAc biosynthesis, the enzyme and its gene were isolated from porcine kidney cortex. Escherichia coli cells transformed with the gene expressed the GlcNAc 2-epimerase having the same properties as those of the GlcNAc 2-epimerase from porcine kidney. Sequence analysis indicated that the gene was capable of synthesizing a 46.5-kDa protein (402 amino acids) with a conserved leucine zipper motif. Homology search for the cloned gene revealed that the GlcNAc 2-epimerase was identical with renin-binding protein (RnBP) in porcine kidney (Inoue, H., Fukui, K., Takahashi, S., and Miyake, Y.(1990) J. Biol. Chem. 265, 6556-6561) (identity: 99.6% in nucleotide sequence, 99.0% in amino acid sequence). That GlcNAc 2-epimerase is a RnBP was confirmed by its ability to bind porcine kidney renin and mask its protease activity. These findings provide unequivocal evidence that the enzyme GlcNAc 2-epimerase is a RnBP.

Amino Acid Sequence↗
PubMed1996

Phosphorylation of actin-binding protein 280 by growth factors is mediated by p90 ribosomal protein S6 kinase.

Although Ras-related small GTPases are believed to control cell proliferation and motility through activation of protein kinase cascades, little is known about the intracellular protein targets of activated kinases. Here we show that the p90 ribosomal S6 kinase 2 (RSK2) phosphorylates actin-binding protein (ABP-280) in intact rat 3Y1 fibroblasts. Growth factors such as fetal calf serum, epidermal growth factor, phorbol 12-myristate 13-acetate, and lysophosphatidic acid stimulate the phosphorylation of serine residues in ABP-280 in quiescent 3Y1 cells. Extracts from 3Y1 cells prepared after stimulation by lysophosphatidic acid, fetal calf serum, and epidermal growth factor retain activated protein kinase activity(s) toward ABP-280 in vitro. ABP kinase activities in lysates from lysophosphatidic acid-stimulated 3Y1 cells can be fractionated by MonoQ anion exchange column chromatography into three peaks having ABP kinase activities. One (ABP kinase peak 1) coelutes with the peak of RSK2 as judged by immunoblotting and S6 peptide kinase assays. Two-dimensional phosphopeptide maps show RSK2 phosphorylated ABP-280 to be phosphorylated at the same site(s) as those stimulated by growth factors in vivo. Incubation of ABP kinase peak 1 fractionated from unstimulated cells with activated ERK2 activates latent ABP kinase activity. These results show RSK2 to phosphorylate ABP-280 in vivo.

Animals↗
PubMed1996

Adrenocorticotropin induces calcium oscillations in adrenal fasciculata cells: single cell imaging.

With fluorescence microscopic imaging, we have demonstrated that the Ca2+ signaling occurred in individual Calcium Green-1 loaded bovine adrenal fasciculata cells upon stimulation with adrenocorticotropin (ACTH) at physiological concentration of 0.1-100 pM. We observed three patterns of Ca2+ signaling which were Ca2+ oscillations (33%), step-like increase in Ca2+ concentration (10%), and Ca2+ oscillations superimposed on step-like increase in Ca2+ (57%). The oscillation in intracellular Ca2+ concentration occurred with a frequency around 0.04 Hz. When Ca2+ signaling upon ACTH stimulation was inhibited by the treatment with EGTA, the corticoid production was considerably suppressed. The results suggest that the Ca2+ signaling is a probable candidate of the second messenger for ACTH-induced steroid hormone synthesis in zona fasciculata cells.

Adrenal Cortex Hormones↗
PubMed1996

Detection of hepatitis C virus specific core protein in serum of patients by a sensitive fluorescence enzyme immunoassay (FEIA).

A protein-capture fluorescence enzyme immunoassay (FEIA) was developed using monoclonal antibodies (mAbs) against recombinant hepatitis C virus (HCV) core protein. Four hybridoma cell lines (5E3, 5F11, 515S, 1080S) were established and characterized. These monoclonal antibodies (mAbs) each had IgG1 and OgG2 isotypes, and recognized major B cell epitopes within the immunodominant nucleoprotein amino terminal subregion. Using mAb 5F11 as the first antibody to the solid phase and beta-D-galactosidase-conjugated mAb 5E3 as the second antibody to the protein, we established a specific HCV core protein capturing FEIA capable of detecting as little as 20 pg/ml of recombinant HCV core protein. HCV core protein in serum was detectable after treatment with 4.0% polyethyleneglycol, 0.5 NaOH, and 5% Triton X-100. The results of a peptide inhibition assay indicated that this FEIA is specific for HCV RNA positive sera. The quantity of HCV core protein detected in serum was significantly correlated to the level of HCV RNA. The detection limit for HCV core proteins was an HCV RNA per titer of approximately 10(4)/ml. Using this FEIA system, the detection ratio of HCV core protein in patients with chronic HCV infection was 92.3% (70/76).

Animals↗
PubMed1996

Tissue-specific expression of an anti-ras ribozyme inhibits proliferation of human malignant melanoma cells.

In this study, we have compared the efficacy of a tissue-specific promoter (tyrosinase promoter) with a viral promoter to express anti-ras ribozyme RNA in human melanoma cells. The retroviral vector containing the tyrosinase promoter was superior in its ability to suppress the human melanoma phenotype in vitro as characterized by changes in growth, melanin synthesis, morphology and H-ras gene expression. These data support the use of tissue-specific expression of anti-oncogene ribozymes as a rational therapeutic strategy in human cancers.

Base Sequence↗
PubMed1996

Human Txk: genomic organization, structure and contiguous physical linkage with the Tec gene.

Txk is a Tec-family tyrosine kinase expressed in mouse and human T lymphocytes. Among the Tec kinases, Txk is unique in that its amino terminal region does not include a pleckstrin homology domain or other known extended functional region. Txk is encoded at human chromosome 4p12 and at a recognized region of conserved synteny on mouse chromosome 5. The genomic organization of Txk consists of 15 exons with strong exon-intron organizational homology to Btk, the only other Tec-family kinase for which the genomic structure is fully known. The human Tec gene also maps to 4p12 and, based on limited studies reported here, possesses organizational homology with Btk and Txk. We have sequenced a continuous region of DNA that contains 3' Tec and 5' Txk exons separated by only a approximately 1.5 kb intergenic region containing the putative promoter region of Txk. The close physical linkage of these Tec-family tyrosine kinases, which are expressed in different hematopoetic cell lineages, suggests their potential for coordinate cis-regulation.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1996

Estrogen receptor (ER) and its messenger ribonucleic acid expression in the genital tract of female mice exposed neonatally to tamoxifen and diethylstilbestrol.

BACKGROUND: Tamoxifen (Tx) is known as an antiestrogen because of its competitive inhibition of estrogen binding to estrogen receptor (ER), and it is used as an estrogen antagonist in the human breast. However, Tx is known to have estrogen agonist activity in the human fetal reproductive tracts and vaginal epithelium and endometrium of postmenopausal women as has been known in the mouse uterus. Therefore, we examined estrogenic potency of Tx on the uterus and vagina in newborn mice and adult ovariectomized mice. METHODS: Using immunohistochemistry and in situ hybridization, we studied changes in expression of ER protein and ER mRNA in the uterus and vagina of C57BL/Tw mice exposed neonatally to 100 micrograms Tx and 0.03-3 micrograms diethylstilbestrol (DES), and changes in expression of ER mRNA in the ovariectomized adult mice given injections of 100 micrograms Tx and 3 micrograms DES. RESULTS: Nuclei of the epithelial and stromal cells in the vagina and of the stromal cells in the uterus showed strong ER immunostaining on the day of birth (= day 0), whereas nuclei of the epithelial cells in the uterus exhibited the ER immunostaining by day 5. In uterine epithelial cells, however, ER was induced by DES, 17 beta-estradiol, testosterone or Tx 24 h after a single injection on day 0, but not by the injection of 5 alpha-dihydrotestosterone, progesterone, or epidermal growth factor. ER in uterine epithelial cells was detected even 12 h after a single injection of 3 micrograms DES on day 0. ER mRNA expression of uterine and vaginal epithelial cells of newborn mice increased 4 h after a single injection of 3 micrograms DES. ER mRNA expression of uterine and vaginal stromal cells in neonatal mice increased 4 h after a single injection of 100 micrograms Tx. In uterine epithelial and stromal cells and vaginal epithelial cells of ovariectomized adult mice, ER mRNA expression increased 12 h after a single injection of 3 micrograms DES and 100 micrograms Tx. CONCLUSIONS: The present study indicates that Tx acts as ER inducer in the uterus and vagina of neonatal and ovariectomized adult mice. However, responsiveness of reproductive tracts to Tx is different between newborn and adult mice.

Animals↗
PubMed1996

Effect of neonatal exposure to diethylstilbestrol and tamoxifen on pelvis and femur in male mice.

BACKGROUND: Permanent abnormalities have been reported in reproductive and non-reproductive organs of mice and humans exposed perinatally to a synthetic estrogen, diethylstilbestrol (DES). Recent studies demonstrated that sex hormones affected the shape of the innominate bone in mice. Therefore, we analyzed the long-term effects of neonatal exposure of DES and tamoxifen, an anti-estrogen, in mouse bones. METHODS: Changes in the pelvis and femur were examined in 1- to 15-month-old C57BL/Tw male mice given 5 daily injections of 3 micrograms DES or of 100 micrograms tamoxifen beginning on the day of birth by measuring contents of calcium (Ca) and phosphorus (P), and the numbers of osteoblasts and osteoclasts. RESULTS: The ash weight of pelvis and femur in neonatally DES- and tamoxifen-treated mice was lower than that in the controls at 2-15 months of age. Contents of Ca and P of pelvis and femur in neonatally tamoxifen-treated mice were lower than in the controls and neonatally DES-treated mice. In neonatally DES-treated mice at 6-12 months, Ca and P contents in the pelvis were lower than in controls, but not different in the femur. The number of osteoblasts per unit length of endocortical surface of the femur in 2- and 3-month-old DES- and tamoxifen-treated mice was lower than that in the controls. The osteoclast number in the femur in DES-treated mice at 2 to 12 months was not different from that in the controls; however, in tamoxifen-treated mice, the number was higher than in the controls. An epiphyseal line was clearly detected in the femur of 12- and 15-month-old DES- and tamoxifen-treated male mice, whereas the line in the controls disappeared after 12 months. CONCLUSIONS: The present results indicate that in male mice, neonatal exposure to DES and tamoxifen induced permanent changes in the pelvis and the femur, and that tamoxifen had a greater effect on bone tissue than did DES.

Age Factors↗
PubMed1996

Magnetic resonance relaxation times in acute hydrostatic pulmonary edema induced by noradrenaline in rats.

Models of pulmonary edema have been used to study the nuclear magnetic resonance (NMR) characteristics of lung water. Several investigators have measured changes in the relaxation times in the permeability type of pulmonary edema, but relatively few have measured relaxation times in the hydrostatic type of pulmonary edema. In this study we determined the characteristics of NMR relaxation times T1, T2 (Hahn spin-echo decay) and water content in acute hydrostatic pulmonary edema induced by noradrenaline administration in rats. Changes in T1 and T2 showed a significant prolongation in hydrostatic pulmonary edema. T2 decay curves for peripheral lung tissues were multiexponential and fit two components [T2 fast (T2f) and T2 slow (T2s)]. With two-component T2 analysis, T2s showed greater prolongation than did T2f. The increase in T2s was significantly correlated with an increase in water content, but the increase in the T2f value was not correlated with water content or with a change in T2s. The T2s component, which likely reflected changes in interstitial water, was more closely related than the T2f component to an increase in water content in hydrostatic pulmonary edema. Results suggested that regional changes in hydrostatic pulmonary edema may be evaluated by multicomponent T2 analysis.

Animals↗
PubMed1996

Chronic hypoxia decreases heterogeneity of pulmonary blood flow distribution in rats.

Pulmonary blood flow (PBF) distribution was studied in 15 chronically hypoxic rats (3 weeks, 10% O2 in N2) breathing 10% O2 (chronic hypoxia, CHx) and after 30 min of breathing air (acute normoxia, ANx). Controls were 15 normoxic littermates (normoxia, Nx) breathing air. Nonradioactive microspheres were infused into the inferior vena cava in the conscious resting state. The lungs were cut into 28 samples, and relative scatter of specific PBF was calculated as (sample activity/sample dry weight)/(total activity/total lung dry weight). In Nx, PBF had a small but significant preferential distribution to the hilar, central regions, with lower blood flow to the peripheral regions (central-to-peripheral pattern). In CHx, however, there was no significant difference between blood flows to the central, middle and peripheral regions of the lung. ANx resulted in no change in PBF distribution. The results indicate that CHx attenuates the central-to-peripheral gradient of PBF distribution, probably due to vascular structural remodeling developed in CHx.

Animals↗
PubMed1996

Immunomodulating and articular protecting activities of a new anti-rheumatic drug, TAK-603.

We investigated the pharmacological activities of a newly synthesized anti-rheumatic drug, TAK-603. (1) In vivo: In adjuvant arthritic (AA) rats, TAK-603 inhibited the hind paw swelling and the body weight loss. The minimum effective dose was 3.13 mg/kg/day (p.o.). Histological and radiographic studies showed that TAK-603 suppressed the development of synovial lesions and joint and bone destruction. TAK-603 was also effective in AA rats when administered for the first 7 days after the adjuvant injection. It suppressed type IV allergy (25 mg/kg/day, p.o.) but had no effect on type III allergy. It had little effect in acute inflammation, analgesic and antipyretic models. These data suggest that TAK-603 acts on the immune system, especially on cellular immunity. (2) In vitro: TAK-603 suppressed the mitogen-induced proliferation of mouse lymphocytes and the ConA-induced IFN-gamma and IL-2 production by rat lymphocytes at 10(-7) to 10(-5) M. It also significantly inhibited the IL-1 induced extracellular matrix reduction in rabbit chondrocytes. It had no effects on prostaglandin E2 (PGE2) production in rat peritoneal cells. These data show that TAK-603 has the ability to suppress the immune system and protect cartilage from destruction. TAK-603 is expected to be a promising drug for rheumatoid arthritis.

Adjuvants, Immunologic↗
PubMed1996

Sulfated colominic acid: an antiviral agent that inhibits the human immunodeficiency virus type 1 in vitro.

Colominic acid is a homopolymer of N-acetylneuraminic acid (NANA), which has an alpha-2,8 ketosidic linkage between its polymer units. In this study, colominic acids were sulfated under different conditions and their antiviral activities against human immunodeficiency virus type 1 (HIV-1) were examined. Sulfated colominic acids, containing 6-12% sulfur, blocked the expression of HIV-1 antigen in MT-4 cells or C8166 cells following exposure to MOLT-4/HTLV-IIIB or HIV-1[GUN-1]. The compounds inhibited syncytium formation upon co-cultivation of MOLT-4 cells (clone 8) with MOLT-4/HTLV-IIIB cells and abolished the production of HIV-1 p24 antigen in culture medium of peripheral blood lymphocytes (PBLs). HIV-1 reverse transcriptase (RT) activity was not directly affected by the drugs. The compounds did not prolong activated partial thromboplastin time (APTT) at 10 and 1.0 microgram/ml, suggesting that they may not have appreciable side effects in vivo. These agents were still able to block the expression of HIV-1 antigen even when the cells were infected with HIV-1 in RPMI-1640 medium containing high percentages of fetal calf serum (FCS). These properties may be therapeutically advantageous if these compounds were considered for possible clinical use.

Anti-HIV Agents↗