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Biomedical subjects

H Sugiyama

Publications and source records attributed to H Sugiyama.

At least 19 recordsLinked to original sources
PubMed1992

The dual role of the cAMP-dependent protein kinase C alpha subunit in T-cell receptor-triggered T-lymphocytes effector functions.

In order to directly evaluate the role of the cAMP-dependent protein kinase (PKA) catalytic (C) subunit in T-cell receptor- (TCR) triggered cytotoxic T-lymphocytes (CTL) effector functions, cells were studied after pretreatment with antisense oligomers complementary to mRNA for the C alpha or C beta subunits. C alpha subunit is shown to be predominantly expressed in CTL. In some experiments the pretreatment of the CTL with the C alpha antisense, but not with the control or C beta antisense oligomers, resulted in the inhibition of cAMP-independent PKA activity without significantly affecting the level of total cAMP-inducible PKA activity. In parallel assays, CTL which were pretreated with the C alpha antisense oligomer had enhanced antigen-bearing target cell-triggered-, anti-TCR monoclonal antibody-triggered-, and phorbol 12-myristate 13-acetate/A23187-triggered exocytosis of granules, as well as enhanced antigen-specific cytotoxicity. In contrast, the TCR-triggered gamma-interferon mRNA expression and gamma-interferon secretion were inhibited in C alpha antisense-pretreated CTL. These results suggest that the C alpha subunit of PKA may have a dual role in regulation of T-lymphocytes effector functions: (i) it may down-regulate TCR-triggered protein-synthesis independent responses such as cytotoxicity and exocytosis, thereby counteracting TCR-triggered activation even in the absence of the second messenger, cAMP, and (ii) the C alpha subunit activity is likely to be required for the nuclear and/or cytoplasmic events in CTL's activation involved in lymphokine synthesis and secretion.

Animals↗
PubMed1992

Enhancement in antioxidant-based hepatoprotective activity of Trolox by its conjugation to lactosylphenylpyranoside.

When Trolox (a polar analog of vitamin E) is conjugated to p-aminophenyl-beta-D-lactopyranoside, the resulting lactosylphenyl Trolox becomes a markedly more stable and effective hepatoprotector than Trolox. In primary rat hepatocytes exposed to xanthine oxidase-hypoxanthine, lactosylphenyl Trolox prolonged cell survival better than did Trolox, mannitol or ascorbate. In rats that underwent 80-min partial hepatic ischemia, infusion of lactosylphenyl Trolox at 2.9 to 5.7 mumol/kg body wt just before reoxygenation salvaged the organ more extensively than did Trolox. Mechanistically, we showed (a) that lactosylphenyl Trolox does not inhibit xanthine oxidase; (b) that lactosylphenyl Trolox effectively scavenges oxyradicals generated with xanthine oxidase and the peroxyl radicals produced with 2,2'-azo-bis(2-amidinopropane) HCl; (c) that both in hepatocytes and in vivo, lactosylphenyl Trolox is distinctly more cytoprotective than either or both of its precursors; and (d) that lactosylphenyl Trolox is amphipathic (i.e., it has both hydrophilic and hydrophobic properties), which enable it to better access and protect the lipid and aqueous milieus of the cell than the lipophile vitamin E and the moderately polar Trolox. Thus there are strong fundamental reasons for lactosylphenyl Trolox being an effective antioxidant-based hepatoprotector.

Animals↗
PubMed1992

Electrophoretic analysis of a natural population of the Thai Paragonimus heterotremus and its genetic relationship to the three Japanese species P. miyazaki, P. ohirai and P. westermani.

A total of 18 enzymes (encoded by 20 loci) from Paragonimus heterotremus collected at a local area in Saraburi, Thailand, were electrophoretically compared with those from the three Japanese species P. ohirai, P. miyazaki and P. westermani using horizontal starch-gel electrophoresis. Relative genetic distances between these species were quantified. The Thai P. heterotremus was found to be most closely related to P. miyazaki and rather distantly related to P. westermani. On the other hand, among the three Japanese species, the closest relationship was observed between P. miyazaki and P. ohirai.

Alleles↗
PubMed1992

Incorporation of radiolabelled amino acids by adult Schistosoma japonicum: further characterization of a putative eggshell precursor protein.

The synthesis patterns of female-specific proteins of Schistosoma japonicum were further investigated with particular reference to the 34 kDa putative eggshell precursor protein. Adult male and female worms of S. japonicum were metabolically labelled with 14C-tyrosine, 14C-glycine and 35S-methionine in vitro. The rates of amino acid incorporation for female worms were significantly higher than for males in all radiolabelling experiments. Labelled proteins were resolved by two-dimensional gel electrophoresis and visualized by fluorography. By using 14C-tyrosine and 14C-glycine, the 34 kDa female protein band resolved into three major spots with pI 6.0, 5.8 and 5.6. On the other hand, labelling studies using 35S-methionine failed to reveal synthesis of any corresponding spots at Mr 34 kDa. These results, together with the observations that eggshell hydrolysates are very rich in glycine but poor in methionine, suggested that the 34 kDa putative eggshell precursor protein of S. japonicum consists of at least three isoelectric forms. In addition, we have demonstrated several other female-specific polypeptides synthesized by this worm.

Amino Acids↗
PubMed1992

The effect of a selective alpha 2-adrenergic receptor antagonist (midaglizole) on the cyclic 3',5'-adenosine monophosphate production in human mononuclear cells.

A selective alpha 2-adrenergic antagonist, midaglizole, has been recently reported to have efficacy in patients with asthma. To understand the mechanisms, we investigated the effect of midaglizole on the cyclic 3', 5'-adenosine monophosphate (cAMP) production in human mononuclear cells (MNCs). MNCs were separated by a histopaque gradient from 10 normal subjects and 10 subjects with asthma. cAMP was measured by RIA kits. Midaglizole (10 mumol/L) significantly enhanced isoproterenol-induced cAMP production in both groups, although midaglizole (from 1 to 100 mumol/L) did not increase the cAMP production by itself. The percent increase in cAMP was more in subjects with asthma (183.8%) than in normal subjects (140.4%); however, the absolute increase was not different. Platelet-activating factor has been demonstrated to inhibit beta-agonist-induced cAMP production in several mammalian tissues, including human MNCs. Midaglizole also prevented platelet-activating factor-induced desensitization of the cAMP response to isoproterenol in MNCs. These findings suggest that midaglizole may be a useful additional agent for the therapy of bronchial asthma through an enhancement of the cAMP production.

Adrenergic alpha-Antagonists↗
PubMed1992

The effect of formoterol on the late asthmatic phenomena in guinea pigs.

We investigated the effects of formoterol, a new, long-acting, selective beta 2-adrenoceptor agonist, on the antigen-induced late asthmatic response (LAR) and airway inflammation in guinea pigs. Animals were sensitized by exposure to aerosolized ovalbumin (2% in saline). After antigen challenge, preceded by administration of an H1-receptor antagonist, specific airway conductance was measured with a two-chambered whole-body plethysmograph. An aerosolized solution of formoterol, isoproterenol, or saline was inhaled 15 minutes before challenge. Bronchoalveolar lavage (BAL) was performed 24 hours after challenge. The provocative concentrations of histamine required to decrease specific airway conductance by 50% were obtained before challenge, at 24 hours, and at 72 hours after challenge. The LAR (52.7% +/- 7.7% of the baseline; p less than 0.02) was observed 6 to 8 hours after antigen challenge. An increased cellular influx in BAL (mainly eosinophils and macrophages) and an increased bronchial responsiveness to histamine occurred 24 hours after antigen challenge. Formoterol completely inhibited the LAR and the cellular increase in BAL; however, isoproterenol failed to prevent either the cellular infiltration or the LAR. Formoterol also decreased the antigen-induced increase in bronchial reactivity. These findings suggest that formoterol has inhibitory effects on the underlying inflammatory processes in antigen-induced asthma in addition to prolonged bronchodilation.

Administration, Inhalation↗
PubMed1992

Continuing V gamma 2 to J gamma 2 rearrangements of murine T cell receptor gamma genes in a B-committed immature cell line.

In SPL2-1-2, a murine B-committed immature cell line transformed with a temperature-sensitive mutant of Abelson virus, T cell receptor (TCR) gamma gene rearrangements, together with IgH gene rearrangements, were induced during culture at a non-permissive temperature (39 degrees C). During 11-12 months of culture, TCR gamma gene rearrangements occurred in all cells. In contrast to TCR gamma genes, neither TCR beta or TCR delta were detected even after 11-12 months of culture at a non-permissive temperature. The majority of the TCR gamma gene rearrangements observed here were V gamma 2 to J gamma 2 joinings and the remaining rearrangements were J gamma 1-linked. V gamma 1 to J gamma 4 and V gamma 3 to J gamma 3 joinings were not detected. Approximately 70% of cells with TCR gamma gene rearrangements produced normal-sized transcripts from the rearranged TCR gamma genes. Cloning and sequencing analysis of a cDNA from the transcripts demonstrated that the whole structure of the cDNA was similar to that of T-lineage cells. These results showed that TCR gene rearrangements were restricted to the gamma genes and that V gamma 2 to J gamma 2 joinings occurred preferentially in this B-committed immature cell line. Furthermore, TCR gamma gene rearrangements also occurred in intracytoplasmic mu-chain producing cells. This indicated that the existence of intracytoplasmic mu-chains did not prevent TCR gamma gene rearrangements, although the existence of mu-chains is known to inhibit further productive IgH gene rearrangements, (allelic exclusion). These results should provide many implications for the mechanism of TCR gene rearrangements, especially that of cross-lineage rearrangements.

Animals↗
PubMed1992

Postnatal development of mRNA specific for a metabotropic glutamate receptor in the rat brain.

We examined the ontogenesis of a subtype of metabotropic glutamate receptors, termed mGluR1, which is linked to phosphoinositide metabolism, in various regions of rat brain during neonatal development. Northern blot analyses of mGluR1 mRNA indicated that mRNA increased monotonously or remained at plateau levels during the first 5 weeks after birth. In situ hybridization analyses supported this conclusion. The result is in contrast with the reported development of the activity in excitatory amino acid-stimulated phosphoinositide turnover during the same period. The latter increases during the first few weeks and then decreases sharply.

Animals↗
PubMed1992

Recognition of the self idiotype by T cells: induction of a rapid increase in cytoplasmic free calcium in T cells recognizing a variable L chain determinant.

To investigate the initial stages of recognition of the self idiotype (Id) by T cells, we examined the early increase in cytoplasmic free calcium ([Ca2+]i) occurring in murine CD4+ T cells specific for a model Id, Id315, following their interaction with the Id. The changes in [Ca2+]i were monitored with stopped-flow fluorometry by loading T cells with fura 2, a Ca(2+)-binding fluorescent dye. An increase of [Ca2+]i in the Id-specific T cell line was dependent on the presence of both antigen-presenting cells (APC) and Id315. When T cells were mixed with APC pulsed with M315 for 90 min at 37 C, a significant increase in T cell [Ca2+]i was observed within one second. A pronounced elevation in [Ca2+]i was also observed in T cells after their interaction with APC which had been pulsed for 90 min with VL-315 Id-containing proteins (such as VL-315, L315, Fv-315 or Fab'-315 fragments). In contrast, pulsing APC for 5 min with the VL fragment produced little or no change in the [Ca2+]i. These results suggest that VL must be further processed by APC before it can be recognized by T cells. Indeed, a synthetic VL region peptide (positions 91-108, designated as P18) produced an elevation in T cell [Ca2+]i when mixed with APC without pulsing.

Animals↗
PubMed1992

Effect of terfenadine on neutrophil and eosinophil chemotactic activities after inhalation of platelet-activating factor in vivo and on neutrophil chemotaxis in vitro.

In this double-blind crossover study we evaluated the effect of terfenadine on the rise in neutrophil chemotactic activity (NCA) and eosinophil chemotactic activity (ECA) in serum induced by platelet-activating factor (PAF) inhalation in 8 asthmatics. Additionally, we examined the direct effect of terfenadine on neutrophil chemotaxis in vitro in 7 allergic subjects. NCA and ECA in serum after PAF inhalation and neutrophil chemotaxis were measured using a modified Boyden chamber method. An initial elevation of NCA after PAF inhalation was inhibited by terfenadine, but the effect was diminished after subsequent PAF inhalations. Terfenadine showed no effect on ECA. In vitro PAF- and fMLP-induced neutrophil chemotaxis were significantly inhibited by terfenadine. These results suggest that terfenadine may have antiallergic properties in addition to its H1 receptor blockade.

Administration, Inhalation↗
PubMed1992

Transitory expression of Thy-1 antigen in immature B cell lines.

In cmu- B220+ Thy-1- murine immature B cells transformed with a temperature-sensitive mutant of Abelson murine leukemia virus, a low level of Thy-1 antigen was transitorily expressed after the shift of the culture temperature from the permissive (35 degrees C) to the non-permissive (39 degrees C) temperature. On the other hand, B220 antigen was persistently expressed regardless of whether the cells were cultured at the permissive or non-permissive temperature. No other T-lineage-specific antigens, CD3, CD4, and CD8 were induced during the culture at the non-permissive temperature. Expression of Thy-1 antigen was confirmed by the detection of a low level of Thy-1-specific mRNA. These results clearly showed that immature B cells could express Thy-1 antigen during proliferation and/or differentiation. The results imply a role for Thy-1 antigen in B cell proliferation and/or differentiation.

Animals↗
PubMed1992

Regulation of Thy-1 gene expression by the methylation of the 5' region of Thy-1 gene and intracellular regulatory factors in immature B cells.

In c mu- B220+ Thy-1- FL2-52-2, an immature B cell line transformed with a temperature-sensitive mutant of Abelson murine leukemia virus(ts OS-59), Thy-1 antigen expression was induced after the shift of the culture temperature from a permissive(35 degrees C) to a non-permissive temperature(39 degrees C), and a Thy-1+ subclone, FL2-52-2-1 was isolated by limiting dilution. Furthermore, since a population of Thy-1+FL2-52-2-1 lost Thy-1 antigen expression during culture at a non-permissive temperature, Thy-1- FL2-52-2-1-1 was isolated from the cultured cells. Methylation analysis by Southern blotting experiments showed that 5' region of the Thy-1 gene was methylated in Thy-1- FL2-52-2 but demethylated in Thy-1+ FL2-52-2-1 and Thy-1-FL2-52-2-1-1. To determine whether or not there exist intracellular regulatory factors responsible for Thy-1 gene expression, Thy-1a allele was transfected into Thy-1(Thy-1.2-) FL2-52-2 and Thy-1- FL2-52-2-1-1. The transfected Thy-1a allele was expressed in Thy-1- FL2-52-2, but not in Thy-1- FL2-52-2-1-1, indicating the presence of the intracellular regulatory factors requisite for Thy-1 gene expression in Thy-1- FL2-52-2. It appeared that in Thy-1- FL2-52-2-1-1, Thy-1 gene was not expressed because of the absence of the intracellular regulatory factors although the 5' region of the Thy-1 gene was demethylated. These results indicated the existence of at least two regulatory mechanisms of Thy-1 gene expression in immature B cells: methylation of the 5' region of the Thy-1 gene and intracellular regulatory factors.

Animals↗
PubMed1992

Photochemical deoxyribose C2' oxidation in 5-iodouracil-containing hexanucleotide.

To investigate photochemistry of 5-iodouracil (IU) in DNA, photoreaction of IU-containing oligonucleotides was examined. It was found that d(GCAIU G C) 2 undergoes selective photochemical C1' and C2' oxidation at the 5' side of IU residue to provide ribonolactone-containing hexamer 1 and erythrose-containing hexamer 2. Upon heating under alkaline conditions, erythrose-containing hexamer 2 was found to undergo retro aldol condensation to provide two fragments having glycolaldehyde termini.

Deoxyribose↗
PubMed1992

[Determination and clinical significance of human hepatocyte growth factor in serum].

Hepatocyte growth factor (HGF) is the most potent mitogen for mature parenchymal hepatocytes in primary culture, and seems to be a hepatotrophic factor that acts as a trigger for liver regeneration after partial hepatectomy and liver injury. In the present study, we evaluated an enzyme-linked immunosorbent assay, using monoclonal antihuman HGF (h-HGF) antibody, for measuring serum h-HGF levels. Intra- and inter-assay coefficients of variation were 2.2-3.3% and 3.4-4.0%, respectively. Detection limit of this method was 0.1 ng/ml, determining by the dilution test. The substances tested did not interfere with this assay, except for high concentrations of hemoglobin. Furthermore, no interference was observed with plasminogen and lipoprotein (a), which show the structural homology to h-HGF, and with various kinds of cytokines. Reference ranges of serum h-HGF determined with 187 healthy subjects were 0.1-0.23 ng/ml. Serum h-HGF concentrations were increased in various kinds of liver diseases, in particular those were significantly higher in fulminant hepatic failure. Furthermore, prognosis of the patients with higher h-HGF values were strikingly worse than those with lower levels. We concluded that the determination of serum h-HGF plays important roles in the early diagnosis and prognosis of fulminant hepatic failure.

Antibodies, Monoclonal↗
PubMed1992

3,5-Dihydroxyphenyl-glycine: a potent agonist of metabotropic glutamate receptors.

An amino acid, 3,5-dihydroxyphenylglycine (DHPG) induced current responses in Xenopus oocytes expressing a metabotropic glutamate receptor clone mGluR1. Apparent EC50 of DHPG for mGluR1 was slightly lower than that of (+-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (ACPD). DHPG responses were partially inhibited by 2-amino-3-phosphonopropionic acid (AP-3). DHPG had no effect on ionotropic glutamate receptors whose expression was induced in the oocytes following injection of poly(A)+ mRNA of rat brains. In hippocampal slices, DHPG produced slow excitation of pyramidal cells, resulting from a depression of Ca(2+)-dependent K+ current and a voltage-dependent K+ current. These results indicate that DHPG is a specific and potent agonist of mGluRs.

2-Amino-5-phosphonovalerate↗
PubMed1992

Functional homology between N-myc and c-myc in murine plasmacytomagenesis: plasmacytoma development in N-myc transgenic mice.

Mouse plasmacytomas induced by pristane oil alone, or in combination with Abelson murine leukemia virus (A-MuLV), regularly carry one of three alternative chromosomal translocations that juxtapose c-myc to immunoglobulin heavy- or light-chain loci. E mu-c-myc transgenic mice develop translocation-free plasmacytomas after induction by pristane oil and/or A-MuLV [Sugiyama, H., Silva, S., Wang, Y., Weber, G., Babonits, M., Rosen, A., Wiener, F. & Klein, G. (1990). Int. J. Cancer, 46, 845-852]. In order to test whether another member of the myc family, N-myc, could play a similar role as c-myc, we treated E mu-N-myc transgenic mice with pristane and helper-free A-MuLV. Of 20 mice that received a single pristane injection followed by A-MuLV, 17 developed plasmacytomas with a mean latency period of 54 +/- 20 days. In a corresponding group that only received a single pristane injection, five out of six transgenic mice developed plasmacytomas with a mean latency period of 142 +/- 32 days. However, after three monthly injections of pristane, all 15 transgenic mice developed plasmacytomas with a mean latency period of 128 +/- 20 days. All plasmacytomas expressed the N-myc transgene, while none of them expressed either c-myc or endogenous N-myc. None of the tumors carried the usual plasmacytoma-associated translocations.

Abelson murine leukemia virus↗