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Biomedical subjects

H Matsui

Publications and source records attributed to H Matsui.

At least 685 records · Page 38Linked to original sources
PubMed1987

Agonist-dependent phosphorylation of the alpha 2-adrenergic receptor by the beta-adrenergic receptor kinase.

Desensitization of the beta-adrenergic receptor, a receptor which is coupled to the stimulation of adenylate cyclase, may be regulated via phosphorylation by a unique protein kinase. This recently discovered enzyme, known as the beta-adrenergic receptor kinase, only phosphorylates the agonist-occupied form of the beta-adrenergic receptor. To assess whether receptors coupled to the inhibition of adenylate cyclase might also be substrates, we examined the effects of beta-adrenergic receptor kinase on the partially purified human platelet alpha 2-adrenergic receptor. Phosphorylation of the reconstituted alpha 2-adrenergic receptor was dependent on agonist occupancy and was completely blocked by coincubation with alpha 2-antagonists. The time course of phosphorylation of the alpha 2-adrenergic receptor was virtually identical to that observed with the beta-adrenergic receptor with maximum stoichiometries of 7-8 mol of phosphate/mol of receptor in each case. In contrast, the alpha 1-adrenergic receptor, which is coupled to stimulation of phosphatidylinositol hydrolysis, is not a substrate for the beta-adrenergic receptor kinase. These results suggest that receptors coupled to either stimulation or inhibition of adenylate cyclase may be regulated by an agonist-dependent phosphorylation mediated by the beta-adrenergic receptor kinase.

Affinity Labels↗
PubMed1987

Nature of recombination involved in excision and rearrangement of human repetitive DNA.

An alphoid-like human repetitive DNA of the Sau3A family is present extrachromosomally and in the chromosomes. In the chromosomes, the DNA is located on chromosome 11 but related sequences are present in chromosome 17. We characterized the nature of the recombination involved in the excision of the extrachromosomal DNA from chromosome 11. The results show that the recombination occurs both between the homologous subunits and between the heterologous subunits with only a 70 to 80% sequence homology among them, suggesting that a DNA structure other than a sequence homology mediates the recombination process. The same type of recombination is responsible for the rearrangement of the related sequences in chromosome 17.

Base Sequence↗
PubMed1987

Cloning, sequencing, and expression of the gene coding for the human platelet alpha 2-adrenergic receptor.

The gene for the human platelet alpha 2-adrenergic receptor has been cloned with oligonucleotides corresponding to the partial amino acid sequence of the purified receptor. The identity of this gene has been confirmed by the binding of alpha 2-adrenergic ligands to the cloned receptor expressed in Xenopus laevis oocytes. The deduced amino acid sequence is most similar to the recently cloned human beta 2- and beta 1-adrenergic receptors; however, similarities to the muscarinic cholinergic receptors are also evident. Two related genes have been identified by low stringency Southern blot analysis. These genes may represent additional alpha 2-adrenergic receptor subtypes.

Amino Acid Sequence↗
PubMed1987

Effect of subthalamic stimulation of adrenal epinephrine and norepinephrine secretion in the rat.

Adrenal medullary secretion in response to subthalamic stimulation was studied in pentobarbital-anesthetized rats. Stimulation of the lateral part of the zona incerta resulted in a significant increase in epinephrine secretion. Stimulation of some other areas of the subthalamus produced a significant decrease in epinephrine as well as in norepinephrine secretion. These results suggest that in the zona incerta excitatory and inhibitory central nervous system mechanisms exist for the control of the adrenal medullary secretion.

Adrenal Medulla↗
PubMed1987

A group of repetitive human DNA families that is characterized by extrachromosomal oligomers and restriction-fragment length polymorphism.

We have recently reported a novel human repetitive DNA (Sau3A family) that exists both in the chromosomes and in the extrachromosomal fraction. Several more clones that hybridized with the Sau3A family were isolated from the extrachromosomal fraction of HeLa cells. Use of these clones as probes has revealed that at least four different types of oligomeric forms of DNA are present in the extrachromosomal fraction. The oligomers consist of one, two, five or 12 subunits of basic 170 base-pair unit DNA, or superimposed forms of two of them. Nucleotide sequencing of these clones indicated that the clones have 70 to 90% sequence homology with human alphoid satellite DNA. These DNA sequences are present also in the chromosomes, as tandemly repeated DNA sequences, and exhibit a considerable degree of restriction-fragment length polymorphism. These results, taken together with the previous findings on Sau3A family DNA, suggest that there is a group of recombination-prone repetitive DNA families in human chromosomes.

Base Sequence↗
PubMed1987

Chemotherapy for gestational trophoblastic tumors.

Virtually 100% of patients with nonmetastatic and low-risk metastatic trophoblastic tumors are now curable by only conventional chemotherapeutic agents such as methotrexate, actinomycin D, or their combination with or without other agents. However, approximately 30% of high-risk patients with metastatic trophoblastic tumors are resistant to conventional chemotherapy. All of the high-risk patients resistant to chemotherapy are those with metastatic choriocarcinoma. Thus, the efficacy of multidrug chemotherapy and combination chemotherapy of cisplatin or VP16-213 with other agents is now being examined.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Effects of glucocorticoids and cycloheximide upon transcription of ribosomal RNA gene in rat liver: application of quantitative S1 nuclease mapping analysis.

The change in the amount of pre-rRNA synthesized in rat liver was examined by S1 nuclease mapping analysis using the probe containing the 5' end of the rat 45S rRNA gene. It was found that the amount of pre-rRNA of adrenalectomized rats, which was about half of the normal level, was increased after administration of dexamethasone attaining to the normal level at 12 h, and that the hormone-induced pre-rRNA synthesis was completely abolished within 1 h after injection of cycloheximide. These results indicate that the glucocorticoids-stimulated initiation of rRNA transcription is mediated by the hormone-dependent short-lived protein(s).

Animals↗
PubMed1987

Interaction of sodium and potassium ions with Na+, K+-ATPase. III. Cooperative effect of ATP and Na+ on complete release of K+ from E2K.

The effects of Na+ and ATP on the K+ binding to Na+, K+-ATPase were investigated by the centrifugation method with radioactive K+ in the absence of Mg2+. In the presence of 10 microM 43KCl, 0.6 and 10 mM Na+ decreased the amount of bound K+ to one-half and zero, respectively. On the other hand, 10 microM and 10 mM ATP decreased the amount of K+ to 60 and 25-40%, respectively. When the combined effect of ATP and Na+ was tested, 10 microM ATP decreased the Na+ concentration giving half-maximal inhibition of the K+ binding to one-third, showing synergistic inhibition by both ligands, though increase in ATP concentration seemed to depress the inhibitory effect of Na+. The synergistic inhibition by ATP and Na+ suggests that the release of K+ from E2K is not completed by the binding of ATP alone but is completed by the binding of Na+ in addition to ATP during the cycle of Na+, K+-dependent ATP-hydrolysis as well as ion-transport.

Adenosine Triphosphate↗
PubMed1987

New approaches for the high-level expression of human interleukin-2 cDNA in Escherichia coli.

We constructed several expression plasmids of human IL-2 gene, some of which directed high-level synthesis of mature IL-2 protein in E. coli. In all the plasmids reported here, we installed the E. coli trp promoter and SD sequence upstream of the IL-2 cDNA. When DNA sequences containing the rho-independent transcription terminator such as those involved in the trpA and lpp gene were inserted downstream of the IL-2 cDNA sequence, the expression level of the IL-2 gene increased up to 5-fold. Moreover, the deletion of either the whole region including A-T and G-C tails or a part of the 3' non-coding sequence resulted in further increase of the expression of the IL-2 gene up to 500-fold. The mature IL-2 produced in E. coli exhibited biological and immunological activities indistinguishable from those of purified IL-2 from a human T cell line, Jurkat-111. The manipulations described here may be useful for the high-level expression of eukaryotic genes in E. coli.

Base Sequence↗
PubMed1987

Use of a series of ompF-ompC chimeric proteins for locating antigenic determinants recognized by monoclonal antibodies against the ompC and ompF proteins of the Escherichia coli outer membrane.

A method is presented for the efficient location of antigenic determinants using a series of chimeric proteins. By means of in vivo homologous recombination between the ompC and ompF genes coding for OmpC and OmpF, homologous proteins of the Escherichia coli outer membrane, a series of ompF-ompC chimeric genes was constructed (Nogami, T., Mizuno, T., & Mizushima, S. (1985) J. Bacteriol. 164, 797-801, and this work). The OmpF-OmpC chimeric proteins expressed by these genes were successfully used to locate antigenic determinants recognized by monoclonal antibodies, which specifically react with either the OmpC or OmpF protein. Interaction between monoclonal antibodies and the chimeric proteins was examined by means of either enzyme-linked immunosorbent assay or immunoblot analysis. The antigenic determinants recognized by three anti-OmpC antibodies and one anti-OmpF antibody were thus located. Finally, the polypeptides covering these regions were chemically synthesized for two of them and then tested as to their reactivity with the antibodies. The peptides reacted with the corresponding antibodies when the former were chemically coupled with bovine serum albumin. Most of the monoclonal antibodies isolated in this work were highly specific to the unfolded monomer of the protein against which the antibody was raised. But they did not react with the trimer, the native form. These results are discussed in relation to the structures and functions of the OmpC and OmpF proteins. The use of a series of monoclonal antibodies for studying the mechanism of protein translocation across the cytoplasmic membrane is also discussed.

Antibodies, Bacterial↗
PubMed1987

Expression of murine interleukin-2 cDNA in E. coli and biological activities of recombinant murine interleukin-2.

Murine interleukin-2 (MIL-2) cDNA was inserted into an expression vector carrying an Escherichia coli tryptophan promoter and was expressed in E. coli. Recombinant MIL-2 produced by E. coli supported the growth of murine CTLL-2 cells, but not that of human T-cell blasts. Recombinant MIL-2 strongly inhibited the binding of recombinant human IL-2 (HIL-2) to murine responder cells, but only very weakly inhibited the binding to human responder cells. Moreover, recombinant MIL-2 induced secondary alloantigen specific cytotoxic T lymphocytes (2 degrees CTL) from memory CTL and activated natural killer (NK) cells in murine systems in the same manner as recombinant HIL-2. The results suggest that the species hierarchy (that MIL-2 derived from native cell culture does not act on human T-cells) is due to the protein moiety, not the sugar moiety, and is to be ascribed to the difference in binding affinity of MIL-2 and HIL-2 to murine and human responder cells respectively, and that recombinant MIL-2 shares identical biological and immunological activities with recombinant HIL-2. Thus, MIL-2 might be a convenient tool for extensive studies of the pharmacological and physiological activities of IL-2 in murine models.

Animals↗
PubMed1987

Role of unique consecutive glutamine repeats in active murine interleukin-2 molecule.

Murine interleukin-2 (MIL-2) cDNA deleted of 11 repeats of a CAG sequence, and that encoded from 33Met to 149Gln were inserted into an expression vector carrying an Escherichia coli tryptophan promoter and were expressed in E. coli, respectively. Recombinant MIL-2 deleted of 11 glutamine repeats (MIL-2(-Gln] supported the growth of murine CTLL-2 cells but recombinant MIL-2 initiated from 34Asp (34Asp-MIL-2) did not. The growth of human T-cell blasts was not supported by MIL-2(-Gln) or 34Asp-MIL-2. MIL-2(-Gln) had identical biological and immunological activities with intact MIL-2, but 34Asp-MIL-2 did not. These results suggest that the consecutive glutamine repeats do not play a role in the biological and immunological activities of MIL-2, but that the peptide sequence around them does, and the species hierarchy that MIL-2 does not act on human lymphocyte is not due to the presence of glutamine repeats in MIL-2.

Animals↗
PubMed1987

[Modeled events and observers' traits underlying observational learning of altruistic behavior].

The present experiments investigated the changes of altruistic responses through observational learning (OL) in elementary school children (ages 10 and 11) with relation to the characteristics of the modeled events and the observers' traits. The former included certain categories of observed materials and the methods of presentation. The latter included subject's impression, empathy for, and evaluation of these materials. The OL was the symbolic modeling of altruistic behavior by presentation of pictures with narration. The response measures were the rating of pre- and post-questionnaires on the altruistic stories. The main result of Experiment I showed that subjects responded selectively to each pretest questionnaire, and that the observational learning was most effective on the similar kind of behavior type. The generalization of OL to other items of categories was also observed. In Experiment II, the combined effect of a pair of observed materials (positive or negative altruistic content) was examined. The effect of OL was highest when the material presented was a P-N pair, lowest when it was a N-N pair. The observers' traits in empathy, impression, and evaluation on observed materials were positively correlated to the effect of OL.

Altruism↗
PubMed1987

Change in the amount of rRNA precursor synthesized in rat ventral prostates after administration of androgen and cycloheximide: application of quantitative S1 nuclease mapping.

The change in amount of pre-rRNA was observed by the use of total cellular RNA isolated from rat ventral prostates and quantitative S1 nuclease mapping. The amount of pre-rRNA from castrated rats was about 20% of that of normal rats, and increased to the normal level 24h after administration of testosterone. Cycloheximide caused a rapid decrease in the amount of pre-rRNA in normal and testosterone-treated castrated rats, to about 20% and 10% of that of normal rats, respectively, 2h after the administration of the drug. These results support the view that the androgen-stimulated initiation of the rRNA gene transcription is mediated by a hormone-dependent short-lived protein(s).

Animals↗
PubMed1987

A possible role for calmodulin in Ca2+-induced swelling of mitochondria.

Ca2+-induced mitochondrial swelling was inhibited by a low concentration of calmodulin antagonists. Two affinities of Ca2+ to mitochondrial swelling were observed: high (2-5 microM) and low (more than 100 microM) systems. The high-affinity change was inhibited by micromolar level of trifluoperazine and W-7, but not by W-5. The possible mechanism of this inhibition and the role of CaM in mitochondria are discussed.

Animals↗