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S Yamamoto

Publications and source records attributed to S Yamamoto.

At least 19 recordsLinked to original sources
PubMed1992

Structure and chromosomal localization of human arachidonate 12-lipoxygenase gene.

Arachidonate 12-lipoxygenase introduces a molecular oxygen into the C-12 position of arachidonic acid to produce 12(S)-hydroperoxy-5,8,10,14-eicosatetraenoic acid. With the aid of cDNA probes for the enzyme, we isolated overlapping lambda clones encompassing the human 12-lipoxygenase gene and flanking regions from a human genomic library. The gene consists of 14 exons with 13 introns and spans approximately 15 kilobases of DNA. All the exon-intron junctions conform to the GT/AG rule. Neither a typical TATA box nor a CAAT box was found in approximately 1-kb sequence of 5'-upstream region of the translation initiation site. However, this region contains several regulatory elements including four GC boxes, two CACCC boxes, three AP-2 binding sequences, and a glucocorticoid-responsive element. The major transcription initiation site was determined by primer-extension analysis as an adenosine residue at 306 bases upstream from the translation initiation codon. The chromosomal localization of the human 12-lipoxygenase gene was examined by fluorescence in situ hybridization, and the gene was assigned to the sub-band p13.1 of chromosome 17.

Arachidonate 12-Lipoxygenase↗
PubMed1992

Identification of a tissue-specific regulatory element within the murine CD14 gene.

We previously isolated and sequenced the 5'-flanking region of the mouse CD14 (mCD14) gene (Matsuura, K., Setoguchi, M., Nasu, N., Higuchi, Y., Yoshida, S., Akizuki, S., and Yamamoto, S. (1989) Nucleic Acids Res. 17, 2132). To define the regulatory elements that control expression of the mCD14 gene, we analyzed the structure of the 5' end of the gene, including a region further upstream of that determined previously. Sequentially 5'-deleted, chimeric, and point mutated clones were tested for the ability to stimulate chloramphenicol acetyltransferase. An 8-base pair sequence, TGATTCAC, at position -255, which resembled the consensus sequence of the 12-O-tetradecanoylphorbol-13-acetate-responsive element (TRE), enhanced the expression of the chloramphenicol acetyltransferase gene in macrophage (aHINS-B3) and non-macrophage (glioblastoma G203 and myeloma NS1) cells. The enhancing ability of the TRE-like sequence (TLS), however, was markedly reduced in G203 cells but not in aHINS-B3 cells when the TLS was followed by the sequence immediately downstream. The TLS and sequence immediately downstream were capable of binding nuclear proteins which were unique to aHINS-B3 cells and macrophages, suggesting that these unique protein regulate the specific expression of the mCD14 gene. Binding of AP-1 to the TLS was also found in aHINS-B3 and G203 cells. Although it is uncertain whether AP-1 is involved in expression of the mCD14 gene, the effect of AP-1 in non-macrophage cells was inhibited by a nuclear protein which binds to the sequence immediately downstream of the TLS.

Animals↗
PubMed1992

Determination of diphenylmethane antihistaminic drugs and their analogues in body fluids by gas chromatography with surface ionization detection.

Eleven diphenylmethane antihistaminic drugs and their analogues were tested for their detection by capillary gas chromatography (GC) with surface ionization detection (SID). The GC-SID response was highest for doxylamine, diphenhydramine and orphenadrine and lowest for terodiline, clemastine and pipethanate. The detection limits for drugs with the highest response were 2-5 pg (ca. 6-20 fmol) on-column (100-250 pg/ml of body fluid). The detection limits with GC-SID were 10-100 times higher than those with GC with nitrogen-phosphorus detection. A detailed procedure for the isolation of the antihistaminics from human whole blood and urine by the use of Sep-Pak C18 cartridges, prior to GC-SID, is also presented. The recoveries of the drugs (50 or 500 pmol), which had been added to 1 ml of body fluids, were > 60%. The baselines remained steady as the column temperature was increased and the background was clean, especially for whole blood extracts.

Benzhydryl Compounds↗
PubMed1992

The effect of histamine on cultured endothelial cells. A study of the mechanism of increased vascular permeability.

The role of endothelial cells in the histamine-induced vascular response was investigated using cultured endothelial cells obtained from human umbilical veins. A single population of histamine H1 receptors was detected in these cells by means of a [3H]mepyramine binding assay. Its Kd was 0.74 +/- 0.07 nM and Bmax was 41.4 +/- 8.68 fmol/mg protein. Actin filaments were distributed as dense bands at the margin of the cells and as sparse microfilament bundles traversing the center of the cells. Histamine caused a decrease in peripheral bands and an increase in longitudinal bands. The changes evoked by histamine were dose-dependent, related to the duration of incubation of the cells with histamine, and blocked by mepyramine, a histamine H1 receptor antagonist. The results suggest that the endothelial cells respond to histamine through the histamine H1 receptor. This may explain one of the mechanisms of histamine-induced vascular response including vascular permeability increase.

Actins↗
PubMed1992

Protein kinase C-dependent and -independent actions of a potent protein kinase C inhibitor, staurosporine.

12-O-Tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C (PKC), induced ornithine decarboxylase (ODC) in primary cultured mouse epidermal cells. Staurosporine, a potent protein kinase C inhibitor, also induced ODC activity. Both TPA- and staurosporine-caused ODC inductions were markedly suppressed in the PKC-down-regulated cells. Another PKC inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), inhibited both TPA- and staurosporine-caused ODC inductions. H-7 by itself never induced ODC activity. Under our experimental conditions, staurosporine induced no detectable phosphorylation of endogenous proteins. TPA induced a translocation of PKC from cytosol to membrane whereas an optimal concentration of staurosporine to induce ODC did not induce an obvious translocation of PKC. Indomethacin, a cyclooxygenase inhibitor, inhibited staurosporine-caused ODC induction, but not TPA-caused ODC induction. Staurosporine induced specific morphological changes of epidermal cells both in normal and in PKC-down-regulated cells. These results indicate that staurosporine induces ODC activity in a PKC-dependent manner and morphological changes possibly through a PKC-independent mechanism. The mechanism of ODC induction caused by staurosporine may be in some way different from that caused by TPA.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Two regions in human DNA polymerase beta mRNA suppress translation in Escherichia coli.

Although human DNA polymerase beta (DNA pol beta) shows 96% identity with rat DNA pol beta at the amino acid level, it is weakly expressed in Escherichia (E.) coli relative to the rat enzyme. The mechanism of this suppression was investigated. Pulse-chase protein labeling and steady state mRNA analysis showed that mature human DNA pol beta protein is relatively stable in E. coli and the levels of human and rat DNA pol beta mRNA were comparable indicating that the human DNA pol beta expression is suppressed at the translational level. By systematic expression analysis of a number of chimeric genes composed of human and rat cDNAs, two strong translational suppression regions were mapped in the human DNA pol beta mRNA; one was named TSR-1, corresponding to CGG encoding arginine (arg) at position 4 and the other, termed TSR-2, is located between codons 153 and 199. Since substitution of the rat Arg-4 codon with synonymous codons showed strong effects upon the expression level, we propose that the arg codon at the N-terminal coding region plays a role in modulating expression.

Amino Acid Sequence↗
PubMed1992

Sensitive determination of phenothiazines in body fluids by gas chromatography with surface ionization detection.

Fourteen phenothiazine derivatives were tested for their detection by gas chromatography (GC) with surface ionization detection (SID). The sensitivity of GC-SID was highest with trimeprazine and levomepromazine, which contain aliphatic tertiary amino side chains, and lowest with thiethylperazine and thioproperazine, which contain sulphur residues. Chlorpromazine, trimeprazine and promazine showed excellent linearity between the SID response and the drug amount in the range 0.25-3.0 pmol on-column. Their detection limits were as low as ca. 5-10 pg (15-30 fmol) on-column (250-500 pg per ml of body fluid). A detailed procedure for isolation of phenothiazines from human whole blood and urine using Sep-Pak C18 cartridges, before the GC with SID, is also presented. The recoveries of the drugs (100 pmol), which were added to 1 ml of whole blood or urine, were more than 79%. The baselines remained steady as the column temperature was increased.

Chromatography, Gas↗
PubMed1992

Mitochondrial changes in phospholipid molecular species during the increased oxidative phosphorylation after hepatectomy.

The changes in liver mitochondrial and microsomal phospholipid molecular species were analyzed during the period of remarkably increased oxidative phosphorylation following partial hepatectomy in rabbits. At 24 hours after hepatectomy, phosphorylative activity increased significantly from 69.7 +/- 5.5 to 118.5 +/- 5.7 nmol of ATP synthesized/min/mg protein, compared to the sham operated group. The ratio of phosphatidylethanolamine to phosphatidylcholine (PE/PC) in mitochondria increased significantly in the hepatectomy group compared with the sham operated group. Remarkable changes in molecular species were observed in mitochondrial phosphatidylethanolamine. 1-Stearoyl-2-arachidonoyl species decreased in the hepatectomy group. On the other hand, microsomal phospholipids hardly changed compared with mitochondrial ones. The change in content of 1-stearoyl-2-arachidonyl phosphatidylethanolamine in mitochondria tended to return to normal levels concomitant with the normalization of phosphorylative activity. The changes in content of mitochondrial phospholipids, especially phosphatidylethanolamine, might also be related to enhancement of phosphorylative activity.

Animals↗
PubMed1992

Inhibitory effects of endothelin-3 on vasopressin release from rat supraoptic nucleus in vitro.

Endothelin (ET) is thought to be involved in the central regulation of body water metabolism. A recent perfusion study of rat hypothalamus showed that ET has a direct stimulatory action on arginine-vasopressin (AVP) release. This study was undertaken to investigate whether ET acts directly on AVP release for supraoptic nucleus (SON) neurons, using brain slices containing only the SON. It was demonstrated that ET inhibited the AVP release dose-dependently from 10(-11) M to 10(-6) M. No difference of the effects of ET-1 and ET-3 on AVP release was observed. These results suggest that ET directly inhibits SON neurons through the ETB receptor.

Animals↗
PubMed1992

Protective effect of NGF atelocollagen mini-pellet on the hippocampal delayed neuronal death in gerbils.

Very recently, contradictory results were presented as to the effects of exogenous nerve growth factor (NGF) on the hippocampal delayed neuronal necrosis following transient ischemia. In the present study, we administered a large amount of NGF with the atelocollagen mini-pellet system, measured the local NGF contents, and evaluated the effect of this neurotrophic factor on the postischemic hippocampal pyramidal cells in gerbils. We concluded that the exogenous NGF, when given continuously at sufficient concentrations, prevents pyramidal cell damage. The possible cause of discrepancy in previous studies is discussed.

Animals↗
PubMed1992

Isolation and partial characterization of a compound with siderophore activity from Vibrio parahaemolyticus.

A compound with siderophore activity was purified by successive column and thin layer chromatographic procedures from Dowex 1 x 8 extracts of culture supernatants of Vibrio parahaemolyticus AQ 3354. The strain synthesized the compound in culture media containing less than 2 microM added FeCl3. Hydrolysis of the compound yielded alanine, ethanolamine, citric acid and 2-ketoglutaric acid. The 1H-NMR spectrum exhibited the presence of a residue from each of these components in the intact molecule. The fast-atom bombardment mass spectrum of the methyl ester derivative indicated a prominent ion at m/z 477, probably corresponding to [M + 1] ion. Other strains of V. parahaemolyticus were also found to produce this compound when grown in an iron-limited medium.

Cell Fractionation↗
PubMed1992

Unique palindromic sequences in synthetic oligonucleotides are required to induce IFN [correction of INF] and augment IFN-mediated [correction of INF] natural killer activity.

Thirty-mer single-stranded oligonucleotides, with a sequence chosen from the known cDNA encoding the 64-kDa protein named Ag A or the MPB-70 protein of Mycobacterium bovis BCG and the human cellular proteins such as complement component 1 inhibitor and Ig rearranged lambda-chain, were used to dissect the capability to induce IFN and to augment NK cell activity of mouse spleen cells by coincubation in vitro. Three with the hexamer palindromic sequence as GACGTC were active, whereas two kinds of oligonucleotides with no palindrome were inactive. The oligonucleotides containing at least one of the different palindromic sequences showed no activity. When a portion of the sequence of the inactive oligonucleotides was substituted with either palindromic sequence of GACGTC, AGCGCT, or AACGTT, the oligonucleotide acquired the ability to augment NK activity. In contrast, the oligonucleotides substituted with another palindromic sequence such as ACCGGT was without effect. Furthermore, exchange of two neighboring mononucleotides within, but not outside, the active palindromic sequence destroyed the ability of the oligonucleotides to augment NK cell activity. Stimulation of spleen cells with the substituted oligonucleotide, A4a-AAC, induced production of significant amounts of IFN-alpha/beta and small amounts of IFN-gamma. Augmentation of NK activity of the cells by the oligonucleotide was ascribed to IFN-alpha/beta production. These results strongly suggest that the presence of the unique palindromic sequences, such as GACGTC, AGCGCT, and AACGTT, but not ACCGGT, is essential for the immunostimulatory activity of oligonucleotides.

Animals↗
PubMed1992

Molecular structure and function of the porcine arachidonate 12-lipoxygenase gene.

The gene encoding arachidonate 12-lipoxygenase was cloned from a porcine EMBL3 genomic library using a cDNA probe of the enzyme, and its nucleotide sequence was determined. The gene consists of 14 exons with 13 introns, and spans approximately 8 kilobases. Analysis of splice junctions indicated that all of the splice donor and acceptor sites conformed to the GT/AG rule. An approximately 1-kilobase region upstream of the coding sequence contains nine GC-boxes for potential Sp1-binding sites at positions -77, -135, -145, -165, -214, -636, -643, -684, and -813. There are two sets of AP-2 binding sequence at positions -234 and -402. Neither typical TATA box nor CCAAT box is found in this region. The transcriptional start site was determined by primer extension analysis, and was tentatively identified as a cytidine residue located 19 bases upstream from initiation codon. Southern blot analysis revealed the presence of one copy of 12-lipoxygenase gene per haploid genome. We found striking similarities in genomic organization as well as the promoter sequences between the porcine 12-lipoxygenase and the rabbit 15-lipoxygenase genes, suggesting that these genes are evolutionarily related.

Amino Acid Sequence↗
PubMed1992

Short-cut method for predicting the productivity of affinity chromatography.

A method was developed for predicting the productivity P (amount of the target protein recovered per unit volume per unit time) of affinity chromatography (AFC) and similar chromatographic operations. The constant-pattern approach was employed for describing the breakthrough curve. It was found that P increases with increasing u at low u regions and there is a maximum in the P-u curve. The u value that gives the maximum P (uM) was derived as a function of the number of transfer units, n. The experimental breakthrough curves for several different packing media systems such as 40- and 10-microns porous particles, 2.5-microns non-porous particles and surface-derivatized membrane media were measured, from which the n values were determined. The uM values were then calculated using the n values. It is suggested that the present method is useful for the rapid survey of the operating conditions in scaling-up AFC and similar chromatographic operations.

Chromatography, Affinity↗
PubMed1992

Human soluble IL-6 receptor: its detection and enhanced release by HIV infection.

By using a fluorescence sandwich ELISA for the quantification of soluble human IL-6R, normal human PBMC were found to be induced to release IL-6R into culture supernatant by stimulation with PHA. Furthermore, certain promonocyte cell lines and human T-cell leukemia virus I (HTLV-I)-positive cell lines produced sIL-6R into culture supernatants constitutively. However, this was not found with HTLV-I negative T cell lines and Burkitt's B cell line. In addition, generation of supernatant IL-6R of the promonocyte cell line was significantly increased 27-fold after PMA treatment and sevenfold after infection with HIV. The released IL-6R molecules were characterized as an apparent m.w. of 50 to 55 kDa by both size-exclusion HPLC and immunoprecipitation of the soluble protein with IL-6R-specific mAb followed by SDS-PAGE analysis. Furthermore, increased levels of serum IL-6R were detected in blood donors seropositive for HIV. Moreover, the released IL-6R could bind efficiently to purified rIL-6 on solid phase and suppressed the proliferative responses of PBMC. These results suggest that the release of soluble IL-6R might be linked to regulatory functions of immune responses induced by IL-6 stimulation during normal and human retrovirus-infected cell growth and differentiation.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

[Preliminary specification of X-ray CT for lung cancer screening (LSCT) and its evaluation on risk-cost-effectiveness].

In Japan mass screening for lung cancer is widely performed by chest X-ray film of 10 x 10 cm, with sputum cytology for high-risk groups. However, the effectiveness of the present mass screening program for lung cancer has been less than expected, although some date have shown improvement of the survival rate as a result of mass screening. We propose a new X-ray CT method of screening for lung cancer called Lung Cancer Screening CT (LSCT). The preliminary specifications for LSCT are as follows: scan speed is within 10 sec for a 40 cm length with a 1 cm slice thickness, and the absorption dose for lung is less than 1 cGy. A computer-assisted diagnostic system is necessary for image reading. The risk-benefit analysis of LSCT indicates that Japanese men and women over 45 years old can be screened in 1992 and thereafter. The cost per person.year of LSCT screening is estimated to be 1.4 x 10(6) yen for a population incidence rate of 50 x 10(-5) person/year and average life expectancy of 30 years. In 1992 the above condition will be satisfied by men aged 55 years old and above, but not by women of any age. We believe that LSCT should be developed further and tested in the high-risk group of men with an incidence rate of 100 x 10(-5) persons/year or more.

Adult↗
PubMed1992

Sensitive determination of cystathionine and assays for cystathionine beta- and gamma-lyase, as well as cystathionine beta-synthase, using high-performance liquid chromatography.

Cystathionine was cleaved into 2-ketobutyric acid, cysteine and ammonia by cystathionase. 2-Ketobutyric acid was converted into 3-ethyl-2-hydroxy-6,7-dimethoxyquinoxaline (EHDQ) by reaction with 1,2-diamino-4,5-dimethoxybenzene. When EHDQ was measured in a mobile phase of pH 2.1 using high-performance liquid chromatography with ultraviolet detection, 250 pmol of L-cystathionine in 250 microliters of the reaction mixture could be determined. Because EHDQ has a strong fluorescence in a mobile phase of pH 6.5 at 447 nm, on excitation at 365 nm, as little as 2.5 pmol of cystathionine in 250 microliters of the reaction mixture could be determined by high-performance liquid chromatography with fluorimetric detection. Cystathionase activity was assayed on the basis of the same principle by determining cystathionine in as little as 63 ng of rat liver by fluorimetric detection. Cystathionine beta-synthase activity was measured by the same method by determining cystathionine formed in only 113 ng of wet weight of rat liver. Using these methods, both cystathionine beta- and gamma-lyase activities in Saccharomyces cerevisiae were determined, because quinoxaline derivatives from pyruvate and 2-ketobutyrate could be measured simultaneously by high-performance liquid chromatography.

Animals↗