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Biomedical subjects

I Tanaka

Publications and source records attributed to I Tanaka.

At least 253 records · Page 14Linked to original sources
PubMed1995

The appearance of male gamete-specific histones gH2B and gH3 during pollen development in Lilium longiflorum.

The male gametic (generative) nucleus within the nearly mature pollen of Lilium longiflorum contains specific variants of histone H2B and H3, which have been designated gH2B and gH3, respectively. Using specific antibodies raised against gH2B and gH3, we examined in detail the temporal and spatial aspects of the appearance of these histone variants during male gametogenesis. Neither gH2B nor gH3 was detected in microsporocytes during meiotic division or in microspores before microspore mitosis. However, both gH2B and gH3 were abundantly present in mid bicellular pollen and these histones continued to be detectable in germinated pollen tubes after pollination. Furthermore, immunocytochemistry revealed that these proteins were present not only in generative nuclei during the maturation process, but also in the two sperm nuclei formed by division of the generative nucleus. By contrast, these proteins were not found in the vegetative nuclei. It appears, therefore, that both gH2B and gH3 are specific to male gametic (generative and sperm) nuclei in L. longiflorum. The results also suggest that these male gamete-specific histones might be newly synthesized in the progenitor of sperm cells for the differentiation of male gametes, as occurs in spermatogenesis in animals.

Cell Differentiation↗
PubMed1995

Effects of nickel oxide on the production of tumor necrosis factor by alveolar macrophages of rats.

To evaluate the effect of green nickel oxide (NiO) on the production of tumor necrosis factor (TNF) by alveolar macrophages, alveolar macrophages were exposed to NiO in vitro and in vivo. For the in vitro study, rats alveolar macrophages were incubated with NiO on a microplate for 24 h. TNF activity in the culture supernatant was determined by the L929 bioassay. Rats alveolar macrophages cultured with 100 and 200 micrograms/mL of NiO in vitro induced the production of TNF, however, it was not statistically significant compared with the control that was free from NiO exposure. For exposure in vivo, rats were divided into two groups. Five were exposed to a daily concentration of 11.7 +/- 2.0 mg/m3 of NiO for an 8-hr/d, 5 d/wk, for 4 wk, and five rats (control) were kept in a cage and not exposed to NiO. Bronchoalveolar lavage was performed and the recovered alveolar macrophages were incubated on a microplate for 24 h. TNF production by exposed alveolar macrophages was significantly higher than that of controls.

Acid Phosphatase↗
PubMed1995

Measurement of anti-factor VIII IgG, IgG4 and IgM alloantibodies in previously untreated hemophilia A patients treated with recombinant factor VIII. Kogenate Japanese Clinical Study Group.

Using enzyme-linked immunosorbent assay (ELISA), we measured anti-factor VIII immunoglobulin G (IgG), IgG4 and IgM in serum samples obtained from hemophilia A patients treated with a recombinant factor VIII (rFVIII) preparation (Kogenate). Twelve pre- and post-treatment serum samples from 3 previously untreated patients who developed an inhibitor (alloantibody) were evaluated. Both rFVIII and plasma-derived factor VIII (pdFVIII) were used as antigen. Serum samples were diluted 37.5-fold. For the measurement of IgM antibody, protein A Sephadex suspension was added to the patients' serum samples and the supernatant was assayed. Anti-human IgG, IgG4, and IgM monoclonal antibodies labelled with peroxidase were added and absorbance at 450nm was determined. The reactivity of the IgG antibody with rFVIII and pdFVIII was extremely low. Samples containing the IgG4 inhibitor with a neutralizing activity of approximately 7.5 Bethesda units (BU)/ml resulted in absorbance values of 0.451-0.551, thus demonstrating a considerably high degree of sensitivity. The correlation between the neutralizing activity and reactions of the IgG4 antibody with rFVIII and pdFVIII antigens was high, with correlation coefficients of 0.912 and 0.966, respectively. Furthermore, the correlation coefficient between the measured absorbance values for the antibody reacted with pdFVIII and rFVIII was 0.961. No correlation was found between the reactivity of IgM to rFVIII and pdFVIII.

Adult↗
PubMed1995

Common inhibitory effects of human anti-C2 domain inhibitor alloantibodies on factor VIII binding to von Willebrand factor.

Factor VIII (FVIII) inhibitor alloantibodies obtained from seven severe haemophilia A patients were examined for their binding regions and their effects on FVIII binding to von Willebrand factor (vWF). Immunoblotting analysis with a panel of recombinant fragments demonstrated that the binding regions of antibodies in cases 1-5 were contained in the C2 domain of the light chain. Antibodies from cases 1 and 2, which recognized an epitope within residues 2248-2312, completely inhibited FVIII/vWF binding in an ELISA (IC50: 5.0 and 9.0 micrograms/ml, respectively). Antibodies from case 3 recognizing 2170-2312 and case 5 recognizing 2170-2327 also inhibited FVIII/vWF binding (IC50: 110 and 400 micrograms/ml, respectively). Case 4 antibodies recognizing 2218-2307 showed barely detectable inhibition and cases 6 and 7 antibodies recognizing the 44 kD heavy chain, did not inhibit. Our results demonstrate that all anti-C2 alloantibodies with epitopes that extend to the residue 2312 inhibit vWF binding and that an overlap of the inhibitor epitope with residues 2308-2312 is critical for maximal inhibition of vWF binding. Prevention of FVIII/vWF binding appears to be a common property of anti-C2 domain inhibitor alloantibodies.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

Altered gene expression of natriuretic peptide receptor subtypes in the kidney of stroke-prone spontaneously hypertensive rats.

1. To elucidate the physiological and pathophysiological role of the natriuretic peptide system in the progression of hypertensive renal disease, we examined the gene expression of natriuretic peptide receptor subtypes, guanylate cyclase-A (GC-A), guanylate cyclase-B (GC-B) and clearance receptor (C receptor), in the kidney of stroke-prone spontaneously hypertensive rats (SHRSP) at 8 and 20 weeks of age, and compared them with their gene expression in age-matched Wistar-Kyoto (WKY) rats. 2. Northern blot analyses revealed that messages for three natriuretic peptide receptor subtypes were expressed in the kidney, and their expressions were higher in the glomeruli than in the whole kidney in each strain. 3. In 20 week old rats with established hypertension, the glomerular concentration of GC-A mRNA was significantly higher in SHRSP than in WKY. The concentrations of GC-B and C receptor mRNA in the glomeruli tended to increase and decrease, respectively, but they were not statistically significant in SHRSP. 4. In 8 week old rats, the glomerular concentrations of GC-A, GC-B and C receptor mRNA were not significantly different between SHRSP and WKY. 5. This study demonstrates that in the progression of hypertension, the expression of GC-A, which mediates biological actions of natriuretic peptides, is enhanced in the kidney of SHRSP compared to that of WKY. Together with the augmented secretion of the ligands previously revealed, altered expression of natriuretic peptide receptor subtypes in SHRSP may have a deterrent role in the development of hypertension and its renal complications.

Animals↗
PubMed1995

Preparation of a monoclonal antibody against mouse brain natriuretic peptide (BNP) and tissue distribution of BNP in mice.

1. In order to explore the significance of brain natriuretic peptide (BNP), a cardiac hormone secreted from the ventricle, in mice, we prepared a monoclonal antibody against mouse BNP (mBNP) and established a specific radioimmunoassay (RIA) for mBNP. 2. A monoclonal antibody, KY-mBNP-I, was prepared by the fusion of mouse myeloma cells X63-Ag8.653 with spleen cells of the BALB/c mouse immunized with synthetic mBNP[108-121] conjugated to bovine thyroglobulin. KY-mBNP-I belonged to an IgG2a subclass and showed a high affinity for mBNP (Ka = 1.8 x 10(11) mol/L-1). 3. The RIA established that using KY-mBNP-I was highly sensitive and specific for mBNP, with an IC50 value of 3 fmol/tube and cross-reactivities of less than 0.003% with related natriuretic peptides. mBNP-like immunoreactivity (mBNP-LI) was detected in the mouse atrium (0.35 +/- 0.02 nmol/g), ventricle (20.5 +/- 0.5 pmol/g) and kidney (0.50 +/- 0.05 pmol/g), but not in other tissues including brain. 4. Gel filtration analysis revealed that the major component of tissue mBNP-LI was co-eluted with synthetic mBNP[77-121], a 45-amino acid mature peptide. 5. The monoclonal antibody and RIA for mBNP established here will provide useful tools to investigate the functional significance of BNP in mice, coupled with the genetic engineering approach.

Animals↗
PubMed1995

Endothelin-induced activation of mitogen-activated protein kinases in glomerular mesangial cells from normotensive and stroke-prone spontaneously hypertensive rats.

1. Kinase assay in myelin basic protein (MBP) containing polyacrylamide gels revealed that endothelin-1 (ET-1) and ET-3 increased MBP kinase activities in glomerular mesangial cells (MC) from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rat (SHRSP). ET-1 stimulated MBP kinase activities more potently than ET-3. 2. Immunoprecipitation with anti-41-kDa MAPK antiserum showed that the MBP kinases activated by ET-1 correspond to 43- and 41-kDa MAPK. 3. Since Phorbol 12-myristate 13-acetate, a direct activator of protein kinase C, also activated MAPK, protein kinase C was suggested to mediate ET-induced activation of MAPK. 4. These results suggest that MAPK may mediate the ET actions in glomerular mesangial cells from normotensive rats as well as spontaneously hypertensive rats. Since ET is produced by vascular endothelial cells of the kidney and glomerular mesangial cells, the ET signalling pathway may have some physiological and pathophysiological significance in vivo glomerulus.

Animals↗
PubMed1995

Gene expression of prostacyclin receptor in the hypertrophied heart of spontaneously hypertensive rats.

1. Prostacyclin elicits potent vasodilation and inhibition of platelet aggregation through binding to its membrane receptor. The impairment of prostacyclin receptor activity is implicated in various human cardiovascular diseases. We recently succeeded in molecular cloning of cDNA for the mouse, rat, and human prostacyclin receptors. 2. In the present study, we examined the mRNA expression of the prostacyclin receptor in various rat tissues, and further investigated its gene expression in the hypertrophied cardiac ventricles of stroke-prone spontaneously hypertensive rats (SHRSP). 3. In rat tissues, a single RNA band of approximately 3.7 kb was detected by northern blotting analysis using rat prostacyclin receptor cDNA as a probe. In adult Wistar rats, abundant mRNA expression was observed in the aorta, lung and spleen. Substantial amounts of transcript were expressed in the heart, pancreas, thymus and stomach. In contrast, no mRNA expression was detected in the brain. 4. We further examined the mRNA expression of the prostacyclin receptor in the ventricles of 21 week old SHRSP. The ventricles of SHRSP showed remarkable hypertrophy, compared with those of age-matched Wistar-Kyoto (WKY) rats. The expression of prostacyclin receptor mRNA in the hypertrophied ventricles of SHRSP was almost equivalent to that in the ventricles of WKY. 5. The present study revealed the gene expression of the prostacyclin receptor in various rat tissues, and further demonstrated the receptor mRNA expression in hypertensive cardiac hypertrophy. The present study will give a clue to investigate the clinical implication of prostacyclin and its receptor.

Animals↗
PubMed1995

Stable expression and coupling of cardiac L-type Ca2+ channels with beta 1-adrenoceptors.

A number of neurotransmitters modulate cardiac dihydropyridine-sensitive L-type Ca2+ channels through several homologous G protein-coupled receptors. Previous studies that have examined receptor-Ca2+ channel interactions have suffered because of the coexpression of various receptor subtypes in native cells. To study the functional coupling of a particular receptor subtype to these channels, rabbit cardiac Ca2+ channel alpha 1 and skeletal beta and alpha 2/delta subunits were stably expressed in baby hamster kidney cells. In this stable cell line, Ca2+ channels remained at high levels (> 1000 fmol/mg protein, or 2700 channels per cell) over extended times. The expressed recombinant Ca2+ channels displayed the voltage dependence of activation and inactivation, unitary conductance, and pharmacology characteristic of native cardiac L-type Ca2+ channels. Subsequent coexpression of the beta 1-adrenoceptors (150 to 300 fmol/mg protein) with the Ca2+ channels resulted in cell responsiveness to the extracellular application of isoproterenol. These results indicate that heterogeneous expression in mammalian cells provides a useful system for studying both biophysical analysis of Ca2+ channel properties and receptor-coupled regulatory processes.

Animals↗
PubMed1995

In-vitro Biological Study to Evaluate the Toxic Potentials of Fibrous Materials.

The potential toxicities of fibrous materials were investigated by measuring the levels of cytokines as well as cytoplasmic and lysosomal enzymes released from alveolar macrophages (AMs) in vitro. Five man-made mineral fibers (ceramic, glass, potassium octatitanate, and two magnesium sulfate whiskers), as well as five natural mineral fibers (UICC chrysotile, crocidolite, amosite, anthophylite, and Turkish erionite) were tested. Basic fiber characteristics, including fiber size, surface area, number, and solubility, were also measured. Tumor necrosis factor (TNF) production, lactate dehydrogenase (LDH) and beta-glucuronidase (BGU) release from AMs exposed to potassium octatitanate, magnesium sulfate whiskers, and ceramic fiber correlated with pathologic changes in the lung according to inhalation studies. The solubility of the man-made mineral fibers also correlated with the half-life of clearance in an in-vivo study. The results suggest that measured values of TNF production, LDH and BGU release in vitro, and fiber solubility combined are a good indicator of the pathogenic potential of fibers in vivo.

Journal Article↗
PubMed1995

Immediate-early, transient induction of the interleukin-1 beta gene in mouse spleen macrophages by ionizing radiation.

In murine spleen cells, x ray irradiation induces the expression of the IL-1 beta gene at multiple phases of the peak time. We analyzed the immediate-early phase of IL-1 beta mRNA accumulation. To determine the lineage of cells that showed the immediate response to irradiation, normal spleen cells were analyzed by Northern blotting and in situ hybridization after separation by magnetic antibodies against specific cell-surface antigens. Although most of the spleen macrophages continuously expressed a low level of IL-1 beta mRNA, a portion of the macrophage population transiently accumulated large amounts of IL-1 beta message immediately after irradiation. A macrophage-like leukemia cell line that resembles these inducible macrophages was identified. A similar immediate-early and transient increase in the IL-1 beta mRNA level occurred when cultured spleen cells were irradiated with a low dose (3 Gy) of x rays. In contrast, the x ray-inducible expression of the IL-1 beta gene was immediate and continuous, not transient, in spleen cells from whole-body irradiated mice. Results of the run-on transcription assay and the determination of the decrease in the message using cultured spleen and macrophage-like leukemia cells indicated that x ray irradiation appears to activate the transcription of the IL-1 beta gene and partially stabilize the message. The results show that the x ray-induced immediate-early accumulation of IL-1 beta mRNA is regulated at both the transcriptional and post-transcriptional levels in an as yet unidentified population of spleen macrophages.

Animals↗
PubMed1995

Expression of IL-1 beta mRNA in mice after whole body X-irradiation.

IL-1 beta is a stimulator of hematopoietic and inflammatory systems, and also acts as a radioprotector. After whole-body exposure to sublethal doses of ionizing radiation, the IL-1 beta mRNA level in spleen cells increases for a short time prior to regeneration of the spleen. We analyzed spleen cells of C3H/He mice after whole-body irradiation with 3 Gy x-rays to determine the cause of this short-term increase in the transcription level. An increase in the level of the message in spleen cells, found by Northern blot hybridization, reached its peak 5 to 7 days after irradiation. There was a low correlation between the curves of the mRNA level and the ratio of monocyte/macrophage lineage cells; a typical source of the message. Spleen macrophages that produce a large amount of the message were found 7 days after irradiation in an in situ hybridization experiment in which heterogeneous spleen cell populations were used. In contrast, spleen cells had no detectable levels of macrophages rich in IL-1 beta mRNA before and 17 days after irradiation. Additionally, the population of message-rich cells was 9.4% of the total number of monocytes/macrophages in the spleen. These results suggest that the short-term increase in IL-1 beta mRNA is a result of the heterogeneous differentiation of a subpopulation of spleen macrophages before regeneration of the spleen.

Animals↗
PubMed1995

Molecular cloning and expression of multiple isoforms of human prostaglandin E receptor EP3 subtype generated by alternative messenger RNA splicing: multiple second messenger systems and tissue-specific distributions.

Five distinct cDNA clones encoding four different isoforms of human prostaglandin (PG) E receptor EP3 subtype were isolated from a human kidney cDNA library. Two cDNA clones differed only in their 3'-untranslated regions. The four isoforms, tentatively named EP3-I, EP3-II, EP3-III, and EP3-IV, which were generated by alternative mRNA splicing, had identical amino acid sequences except for their different carboxyl-terminal tails. Transfection experiments revealed that all the four isoforms show high binding affinities to PGE2, PGE1, and M&B28767, an EP3-specific agonist, whereas their downstream signaling pathways are divergent. M&B28767 increased cAMP concentrations in cells expressing EP3-II and EP3-IV, whereas it inhibited forskolin-induced cAMP accumulations in cells expressing all EP3 isoforms. M&B28767 also stimulated phosphoinositide turnover in cells expressing EP3-I and EP3-II. Northern blot analysis revealed that the EP3 gene is expressed in a wide variety of human tissues. The human EP3 mRNA was present most abundantly in the kidney, pancreas, and uterus. A substantial expression was also detected in the heart, liver, skeletal muscle, small intestine, colon, prostate, ovary, and testis. Furthermore, reverse transcription-polymerase chain reaction analysis demonstrated tissue-specific expressions of the five different EP3 mRNA species. The present study suggests the presence of the multiple systems of PGE2/EP3 isoforms and leads to the better understanding of its physiological and pathophysiological implications in humans.

Alternative Splicing↗
PubMed1995

[A case of mixed connective tissue disease associated with gastric cancer and cancer of the uterine cervix].

We report here a very rare case of MCTD complicating double cancer. A 43-year-old woman with suspected MCTD was admitted because of high fever and lymphadenopathy. The laboratory findings indicated high titers of speckled ANA, anti-RNP, DNA and Scl-70, but anti-Sm. SS-A and SS-B was not detected. Chest CT and Spirogram revealed lung fibrosis, restrictive ventilatory impairment, and decreased diffusion capacity. Biopsy specimen by gastric fiberscope s screening indicated II c advanced type of poorly differentiated adenocarcinoma. After subtotal gastrectomy, she had high fever, pleuritis, leukopenia, butterfly erythema and hypoxemia, which were improved by 30 mg/day of oral prednisolone. One year after from the last operation, she had contact bleeding, and squamous cell carcinoma of the uterine cervix was diagnosed. She had Raynaud's phenomenon 6 months after from hysterectomy.

Adenocarcinoma↗
PubMed1994

Cloning and expression of a cDNA for rat prostacyclin receptor.

A cDNA clone for rat prostacyclin receptor was isolated. The cDNA encodes a protein of 416 amino acid residues (M(r) 44,662) with putative seven transmembrane domains, and belongs to the G protein-coupled receptor superfamily. Specific binding of [3H]iloprost was found in membrane of COS-7 cells transfected with the cDNA (Kd = 1.3 nM) and was displaced with unlabeled prostaglandins in the order of iloprost = cicaprost > PGE1 > STA2 = PGE2 = PGD2 > PGF2 alpha. Northern blot analysis demonstrated that rat prostacyclin receptor mRNA is expressed in the lung, spleen, heart, pancreas, thymus, stomach and aorta.

Amino Acid Sequence↗