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Biomedical subjects

A Suzuki

Publications and source records attributed to A Suzuki.

At least 19 recordsLinked to original sources
PubMed1992

cDNA cloning and sequence determination of the pheromone biosynthesis activating neuropeptide of the silkworm, Bombyx mori.

We have identified the cDNAs encoding pheromone biosynthesis activating neuropeptide (PBAN) using PCR technique. The nucleotide sequence showed that the PBAN gene encodes, besides PBAN, diapause hormone and three putative amidated peptides. These four peptides share with PBAN the C-terminal pentapeptide amide which is corresponding to the shortest fragment with pheromonotropic activity. The organization of the PBAN gene is characteristic of several short neuropeptides and has some degree of similarity to that of the gene for the insect neuropeptide FMRFamide. Thus, the PBAN gene products construct a family of structurally related peptides and have various biological functions.

Amino Acid Sequence↗
PubMed1992

A carboxyl-terminal truncated version of the activin receptor mediates activin signals in early Xenopus embryos.

The function of a carboxyl-terminal truncated version of the Xenopus activin receptor, encoded by a previously isolated gene XSTK2, was investigated in early embryos. The transcript corresponding to the truncated receptor gene was detected throughout embryonic development although the temporal expression pattern was different from that of an intact receptor. Injection of XSTK2 mRNA into early embryos resulted in the formation of a duplicated body axis. Mesoderm induction as evaluated by the activation of the alpha-actin gene in presumptive ectoderm (animal cap) treated with exogenous activin was significantly enhanced by the injection of XSTK2 mRNA. These results suggest that the truncated receptor is capable of transmitting the activin signal to the same extent as the native receptor.

Actins↗
PubMed1992

Single-stranded DNA of 5'-upstream region of the rolC gene interacts with nuclear proteins of carrot cell cultures.

Using the gel retardation assay, proteins of carrot cells capable of binding to a single-stranded DNA of 5'-upstream region of the rolC gene were found. From competition experiments, these DNA-protein interactions were specific to single-stranded nucleotide sequence of Ava S fragment (from -94 bp to +23 bp relative to the transcription initiation site). Methylation interference experiments showed that G residue at the position of -41 bases on the bottom strand was important for DNA-protein binding. This residue was located between CAAT box and TATAA box. Such specific interaction between single-stranded DNA and nuclear proteins may play a role in transcription by RNA polymerase II.

Base Sequence↗
PubMed1992

Effects of baicalein and alpha-tocopherol on lipid peroxidation, free radical scavenging activity and 12-O-tetradecanoylphorbol acetate-induced ear edema.

The effects of baicalein, a flavonoid, and alpha-tocopherol (vitamin E) on lipid peroxidation in rat forebrain homogenates, on free radical scavenging action against diphenyl-p-picrylhydrazyl (DPPH), and on 12-O-tetradecanoylphorbol acetate (TPA)-induced ear edema in mice were studied. Baicalein inhibited lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema as potently as did quercetin and nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, and more potently than BW755C, a mixed cyclooxygenase and lipoxygenase inhibitor. Lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema were also inhibited by alpha-tocopherol. Flavone showed no reaction. These results suggest that lipid peroxidation may play an important role in the pathogenesis of TPA-induced ear edema in mice.

Animals↗
PubMed1992

Effects of simulated left bundle branch block on QRST time-integral values of 12-lead electrocardiograms in patients with and without prior anterior wall myocardial infarction.

The effects of right ventricular pacing, which simulated left bundle branch block (BBB), on QRST time-integral values of 12-lead electrocardiograms (ECGs) were examined, and the clinical usefulness of QRST values for estimating the severity of left ventricular wall motion abnormalities due to a prior anterior wall myocardial infarction (MI) in the setting of left BBB were evaluated. Digitized ECGs were recorded during normal sinus rhythm and simulated left BBB in 38 patients (24 with and 14 without prior anterior wall MI). QRST values were calculated in each lead point of 12-lead ECGs. Data from 608 normal subjects were used as control values; the mean +/- 2 SD of these values was regarded as the normal range. The parameter sigma DE was defined as the sum of the differences between the normal mean QRST value and the QRST values of a given patient in leads where the QRST value was less than the normal range. The correlation coefficient of sigma DE for the 2 activation sequences was highly significant. Although small but significant changes were seen in QRST values in leads I, II, III, aVR, aVF and V1 during simulated left BBB, left precordial leads showed no significant changes in QRST values. A criterion of sigma DE > 40 mV.ms for detecting an anterior wall MI showed a sensitivity of 88%, a specificity of 93%, and a diagnostic accuracy of 89%. The sigma DE was significantly (p < 0.001) correlated with the asynergy index calculated from left ventriculograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗
PubMed1992

Thrombocytosis in patients with tumors producing colony-stimulating factor.

We investigated the cause of thrombocytosis in 14 patients with tumors producing colony-stimulating factor (CSF). Of the 14 patients, 10 had tumors producing granulocyte-CSF (G-CSF) and 4 had tumors producing granulocyte-macrophage--CSF (GM-CSF). Thrombocytosis of greater than 400 x 10(9)/L was noted in 8 of 10 patients with G-CSF-producing tumors and all 4 patients with GM-CSF-producing tumors. Median peak platelet counts were, respectively, 511 x 10(9)/L (range, 384 to 694 x 10(9)/L) and 579 x 10(9)/L (range, 526 to 910 x 10(9)/L) in patients with tumors producing G-CSF and GM-CSF. In most patients, thrombocytosis declined towards the terminal stage. High interleukin-1 (IL-1) and IL-6 levels were found in addition to CSFs in the plasma or culture supernatants of tumor cells obtained from most patients. In patients with GM-CSF-producing tumors, these specimens had megakaryocyte-CSF (Meg-CSF) activity, which was abolished by anti-GM-CSF antibody. These specimens also had megakaryocyte potentiating (Meg-Pot) activity attributable to both GM-CSF and IL-6. In patients with G-CSF-producing tumors, only Meg-Pot activity due to IL-6 was detected. These results indicate that the thrombocytosis in GM-CSF-producing tumors was caused by both the Meg-CSF activity of GM-CSF and the Meg-Pot activity of IL-6 plus GM-CSF, while that in G-CSF-producing tumors was due to the Meg-Pot activity of IL-6.

Adult↗
PubMed1992

Glycoprotein-binding site of dystrophin is confined to the cysteine-rich domain and the first half of the carboxy-terminal domain.

Dystrophin, a protein product of the Duchenne muscular dystrophy gene, is thought to associate with the muscle membrane by way of a glycoprotein complex which was co-purified with dystrophin. Here, we firstly demonstrate direct biochemical evidence for association of the carboxy-terminal region of dystrophin with the glycoprotein complex. The binding site is found to lie further inward than previously expected and confined to the cysteine-rich domain and the first half of the carboxy-terminal domain. Since this portion corresponds well to the region that, when missing, results in severe phenotypes, our finding may provide a molecular basis of the disease.

Amino Acid Sequence↗
PubMed1992

Genes for bone morphogenetic proteins are differentially transcribed in early amphibian embryos.

We have previously demonstrated that activin, a member of the TGF-beta family, has a potent mesoderm-inducing activity in Xenopus embryos. In the course of screening for activin-related genes from Xenopus, we have cloned cDNAs for Xenopus homologue of BMP-2, -4 and -7. Northern blot analysis revealed that these BMP genes are maternally encoded and differentially regulated after fertilization. Alkaline phosphatase-inducing assay using the recombinant BMP proteins has shown that at least BMP-2 and -4 have similar activity to mammalian counterparts.

Alkaline Phosphatase↗
PubMed1992

Molecular cloning of rabbit cytochrome b5 genes: evidence for the occurrence of two separate genes encoding the soluble and microsomal forms.

The rabbit genomic segments for the soluble cytochrome b5 (b5) and microsomal b5 were amplified and isolated, respectively, by means of the polymerase chain reaction using primers corresponding to various portions of the open reading frame of microsomal b5 cDNA. The DNA sequence analysis revealed that the soluble b5 gene has an extra 24 nucleotide long insert which encodes a C-terminal amino acid and a termination codon which are specific to the soluble b5. Except for the insert, the sequences of the soluble and microsomal b5 genes are identical with each other from the 5' end to the 3' end of the open reading frame of the microsomal b5 cDNA. Comparison of the genomic sequences with the cDNA sequences suggested that the soluble and microsomal genes are intronless within their open reading frames. These data indicate that rabbit soluble and microsomal b5 mRNAs are encoded by two highly conserved but separate genes.

Amino Acid Sequence↗
PubMed1992

Endothelin-1-induced prostaglandin E2 production: modulation of contractile response to endothelin-1 in porcine coronary artery.

Endothelin-1 (ET-1, 1 nM) increased the release of prostaglandin E2 (PGE2) in endothelium-denuded smooth muscle strips of porcine coronary arteries. Indomethacin enhanced the amplitude of contraction induced by ET-1 and inhibited the stimulated release of PGE2. PGE2 (0.1-100 nM) attenuated the amplitude of contraction induced by 1 nM ET-1. These results suggest that in the smooth muscle of porcine coronary arteries, ET-1 increased the synthesis of PGE2, which functionally antagonizes the direct vasoconstrictor actions of ET-1.

Animals↗
PubMed1992

Pulmonary surfactant protein A in pleural effusions.

Pulmonary surfactant protein A (SP-A) is known to be a major phospholipid-associated glycoprotein in pulmonary surfactant, which is specific to the lung. Immunohistochemically, expression of SP-A in tumor tissues is found in approximately 50% of patients with lung adenocarcinoma but not in the other histologic types of lung cancer of metastatic lung tumors. In this study, the SP-A content of pleural effusions was determined using an enzyme-linked immunosorbent assay. These results showed that approximately 40% of patients with lung adenocarcinomas (27 of 67) had high levels of SP-A (greater than 500 ng/ml) in their pleural effusions. By contrast, patients with other histologic types of lung cancers, adenocarcinomas of different primary sites, and tuberculosis had low levels of SP-A in their pleural effusions. The determination of SP-A in malignant effusions will contribute to distinguishing primary lung adenocarcinoma from adenocarcinomas of miscellaneous origin.

Adenocarcinoma↗
PubMed1992

pH-dependent membrane fusion and vesiculation of phospholipid large unilamellar vesicles induced by amphiphilic anionic and cationic peptides.

We studied fusion induced by a 20-amino acid peptide derived from the amino-terminal segment of hemagglutinin of influenza virus A/PR/8/34 [Murata, M., Sugahara, Y., Takahashi, S., & Ohnishi, S. (1987) J. Biochem. (Tokyo) 102, 957-962]. To extend the study, we have prepared several water-soluble amphiphilic peptides derived from the HA peptide; the anionic peptides D4, E5, and E5L contain four and five acidic residues and the cationic peptide K5 has five Lys residues in place of the five Glu residues in E5. Fusion of egg phosphatidylcholine large unilamellar vesicles induced by these peptides is assayed by two different fluorescence methods, lipid mixing and internal content mixing. Fusion is rapid in the initial stage (12-15% within 20 s) and remains nearly the same or slightly increasing afterward. The anionic peptides cause fusion at acidic pH lower than 6.0-6.5, and the cationic peptide causes fusion at alkaline pH higher than 9.0. Leakage and vesiculation of vesicles are also measured. These peptides are bound and associated with vesicles as shown by Ficoll discontinuous gradients and by the blue shift of tryptophan fluorescence. They take an alpha-helical structure in the presence of vesicles. They become more hydrophobic in the pH regions for fusion. When the suspension is made acidic or alkaline, the vesicles aggregate, as shown by the increase in light scattering. The fusion mechanism suggests that the amphiphilic peptides become more hydrophobic by neutralization due to protonation of the carboxyl groups or deprotonation of the lysyl amino groups, aggregate the vesicles together, and interact strongly with lipid bilayers to cause fusion. At higher peptide concentrations, E5 and E5L cause fusion transiently at acidic pH followed by vesiculation.

Amino Acid Sequence↗
PubMed1992

[Personal computer-based interpretation experiment system for digital chest images].

We have developed a system of nodule detection interpretation experiment on personal computers. This system is composed of three subsystems: practice, experiment and check modes. In the practice and experiment modes, chest radiographic images, each with or without a nodule, are shown in a random order on the monitor. The reader is then asked to point a location of nodule and to give a confidence rating. In the check mode, a subsystem shows locations of the real nodules and false positive foci on a figure of a chest radiograph. It also shows receiver operating characteristics of each reader. This system can precisely and easily perform an interpretation experiment. Then reader performance in detection of nodules can be accurately and promptly evaluated. This system, therefore, is very useful to perform a large-scale interpretation experiment in a constant reading condition.

Humans↗
PubMed1992

Comparison of the enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III.

The enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III have been compared. Both enzymes were found to degrade insulin in such a way that its receptor binding activity was rapidly lost but its precipitability in trichloracetic acid was only slightly decreased. Both enzymes were also found to be inhibited by chelating agents. The bacterial enzyme, which could be purified in large amounts, was found to contain 0.6 mol of zinc per mol of enzyme but no detectable manganese. The mammalian enzyme but not the bacterial one was inhibited by a sulfhydryl alkylating agent. The two enzymes also differed in substrate specificity. The mammalian enzyme degraded insulin much better than insulin-like growth factor II, whereas the bacterial enzyme degraded them equally. The mammalian enzyme could be labeled by cross-linking to insulin = bombyxin II much greater than insulin-like growth factor I and II much greater than relaxin, while the bacterial enzyme was labeled by insulin-like growth factor II greater than insulin = insulin-like growth factor I much greater than relaxin much greater than bombyxin. Finally, sucrose gradient centrifugation and cross-linking studies both in vitro and in vivo indicated that active human enzyme partially existed as a homo- or heterodimer, whereas the bacterial enzyme was active as a monomer.

Alkylating Agents↗
PubMed1992

Nucleotide sequence of cDNA for the eclosion hormone of the silkworm, Bombyx mori, and the expression in a brain.

The cDNAs encoding eclosion hormone (EH) of the silkworm, Bombyx mori, were isolated and sequenced. The results showed that the pre-EH molecule contains a 26-amino acid signal peptide and a 62-amino acid mature EH. The deduced amino acid sequence agreed with that previously determined by the peptide analysis. The presence of leucine residue at the carboxyl terminal of EH, which had not been detected directly by the peptide analysis, was proved. Primer extension and Northern hybridization analyses revealed that 0.9 kb mRNA is transcribed and it has a 66-nucleotide non-translated sequence at the 5'-end region. In situ hybridization showed that the EH gene is expressed in two pairs of nuerosecretory cells in the brain of 5th instar larva.

Amino Acid Sequence↗
PubMed1992

Purification and molecular cloning of a butyrolactone autoregulator receptor from Streptomyces virginiae.

In streptomyces, low molecular weight compounds termed "autoregulators" have been isolated as primary signal molecules for triggering secondary metabolism and/or cytodifferentiation. Streptomyces virginiae produces a set of autoregulators termed virginiae butanolide A-E which trigger virginiamycin production, and possesses a high-affinity virginiae butanolide receptor (Kim, H.S., Nihira, T., Tada, H., Yanagimoto, M., and Yamada, Y. (1989) J. Antibiot. (Tokyo) 42, 769-778). The virginiae butanolide receptor has now been purified to apparent homogeneity with 14,000-fold purification and an 8.6% activity yield. The purified receptor showed a Mr of 36,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and a maximum ligand binding of 33.0 nmol/mg protein, indicating a 1:1 binding stoichiometry (1.18 mol of virginiae butanolide/36 kDa of protein) between virginiae butanolides and the receptor. Due to a blockage at the amino terminus, fragment peptides were generated by lysyl endopeptidase and five partial amino acid sequences were determined. The gene (vbrA) encoding the virginiae butanolide receptor was identified on a 5.0-kbp BamHI fragment by hybridization to synthetic oligonucleotide probes, cloned, and sequenced. Nucleotide-sequence analysis predicted a 319-amino acid open reading frame (vbrA) in which all the partial amino acid sequences of the receptor appeared, and 166 bp downstream from it another open reading frame for a 144-amino acid protein which was designated as a ribosomal protein L11 from its high homology (62-64%) to the amino acid sequences of ribosomal protein L11 of several origins, and thus denoted as rplK. The C-terminal half of VbrA showed 36% overall homology to the amino acid sequence of an essential protein (NusG) of Escherichia coli. Furthermore, the gene assembly of vbrA-rplk of S. virginiae closely resembled that of nusG-rplK of E. coli, suggesting that vbrA may constitute a part of an essential gene cluster encoding components of transcriptional and translational apparatuses.

Amino Acid Sequence↗
PubMed1992

Possible roles of arachidonic acid and its metabolites in induction of tissue plasminogen activator (t-PA) production in human fibroblast, IMR-90 cells by proteose peptone.

Proteose peptone (p.peptone) had an ability to induce tissue plasminogen activator (t-PA) production by human embryonic lung fibroblast, IMR-90 cells. We previously demonstrated that the induction was closely related to the activation of phospholipase A2 in the cells stimulated by p.peptone. In this report, we describe the involvement of arachidonate metabolism in the induction. The induction was inhibited in a dose-dependent manner by 5,8,11,14-eicosatetraenoic acid (ETYA), an inhibitor of both cycloxygenase and lypoxygenase, and also by nordihydroguaiaretic acid (NDGA), which in low concentrations selectively inhibits lipoxygenase. However, indomethacin, a specific inhibitor of cycloxygenase, had no effect on the induction. 5-hydroxyeicosatetraenoic acid (5-HETE), which is an arachidonate metabolite derived from lipoxygenase pathway, had an inductive effect, but prostaglandin E1 (PGE1), which is a metabolite from cycloxygenase pathway, had no effect on t-PA production by the cells. These results suggest that arachidonate metabolism is involved in the induction of t-PA production in IMR-90 cells by p.peptone, and that arachidonate metabolite(s) from lipoxygenase pathway is responsible for the induction.

Alprostadil↗