514 research outputs found

    Nucleotide-, chemotactic peptide- and phorbol ester-induced exocytosis in HL-60 leukemic cells

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    Undifferentiated and differentiated HL-60 leukemic cells possess nucleotide receptors which functionally couple to phospholipase C via pertussis toxin-sensitive guanine nucleotide-binding proteins (G-proteins). We investigated the role of extracellular nucleotides in the regulation of beta-glucuronidase release in HL-60 cells. In dibutyryl cyclic AMP (Bt2cAMP)-differentiated HL-60 cells, the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMet-Leu-Phe), the phosphorothioate analogue of ATP, adenosine 5'-O-[3-thio]triphosphate (ATP[gamma S]), and UTP increased cytosolic Ca2+ from 100 nM up to 1.2 microM with EC50 values of 4 nM, 1 microM and 100 nM, respectively. In these cells, ATP[gamma S] induced exocytosis with an EC50 of 4 microM and an effectiveness amounting to 50-70% of that of fMet-Leu-Phe. ATP, ITP, UTP, CTP, and uridine 5'-O-[2-thio]diphosphate activated exocytosis as well. Phorbol myristate acetate (PMA) induced exocytosis with an EC50 of 115 ng/ml and an effectiveness similar to that of ATP[gamma S]. Cytochalasin B (CB) differently potentiated exocytosis induced by ATP[gamma S], fMet-Leu-Phe and PMA. Treatment of Bt2cAMP-differentiated HL-60 cells with pertussis toxin (500 ng/ml) for 24 h resulted in ADP-ribosylation of more than 97.5% of the G-proteins. Under these conditions, pertussis toxin almost completely inhibited the increase in cytosolic Ca2+ and beta-glucuronidase release induced by fMet-Leu-Phe but only partially inhibited the effects of ATP[gamma S] and UTP. fMet-Leu-Phe at a non-stimulatory concentration (1 nM) potentiated ATP[gamma S]-induced beta-glucuronidase release in the presence but not in the absence of CB. In contrast, ATP[gamma S] and fMet-Leu-Phe synergistically activated superoxide formation in the absence of CB. PMA potentiated superoxide formation induced by ATP[gamma S] or fMet-Leu-Phe and did not affect exocytosis induced by ATP[gamma S] or fMet-Leu-Phe. In undifferentiated HL-60 cells, fMet-Leu-Phe, ATP[gamma S], UTP and PMA did not induce beta-glucuronidase release. fMet-Leu-Phe did not increase cytosolic Ca2+ in undifferentiated HL-60 cells, whereas ATP[gamma S] and UTP were similarly potent and effective as in Bt2cAMP-differentiated cells. In differentiated HL-60 cells, fMet-Leu-Phe induced aggregation, and ATP[gamma S] induced a transient shape change. Our results show (I) that exocytosis in HL-60 cells does not obligatorily depend on CB. (II) Purine and pyrimidine nucleotides activate exocytosis via pertussis toxin-sensitive and -insensitive signal transduction pathways.(ABSTRACT TRUNCATED AT 400 WORDS

    Some taste substances are direct activators of G-proteins

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    Amphiphilic substances may stimulate cellular events through direct activation of G-proteins. The present experiments indicate that several amphiphilic sweeteners and the bitter tastant, quinine, activate transducin and Gi/Go-proteins. Concentrations of taste substances required to activate G-proteins in vitro correlated with those used to elicit taste. These data support the hypothesis that amphiphilic taste substances may elicit taste through direct activation of G-proteins

    Static Source Code Analysis using OCL

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    The majority of artifacts created during software development are representations of programs in textual syntax. Although graphical descriptions are becoming more widespread, source code is still indispensable. To obtain programs that behave correctly and adhere to given coding conventions, source code must be analyzed - preferably using automated tools. Building source code analyzers has a long tradition and various mature tools exist to check code written in conventional languages, such as Java or C. As new languages emerge (e.g., Domain Specific Languages) these tools can not be applied and building a tool for each language does not seem feasible either. This paper investigates how meta models for textual languages and the Object Constraint Language can enable generic static source code analysis for arbitrary languages. The presented approach is evaluated using three languages (Java, SQL and a DSL for state machines)

    Generation of specific antibodies against the rap1A, rap1B and rap2 small GTP-binding proteins. Analysis of rap and ras proteins in membranes from mammalian cells

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    Specific antibodies against rap1A and rap1B small GTP-binding proteins were generated by immunization of rabbits with peptides derived from the C-terminus of the processed proteins. Immunoblot analysis of membranes from several mammalian cell lines and human thrombocytes with affinity-purified antibodies against rap1A or rap1B demonstrated the presence of multiple immunoreactive proteins in the 22-23 kDa range, although at strongly varying levels. Whereas both proteins were present in substantial amounts in membranes from myelocytic HL-60, K-562 and HEL cells, they were hardly detectable in membranes from lymphoma U-937 and S49.1 cyc- cells. Membranes from human thrombocytes and 3T3-Swiss Albino fibroblasts showed strong rap1B immunoreactivity, whereas rap1A protein was present in much lower amounts. In the cytosol of HL-60 cells, only small amounts of rap1A and rap1B proteins were detected, unless the cells were treated with lovastatin, an inhibitor of hydroxymethylglutaryl-coenzyme A reductase, suggesting that both proteins are isoprenylated. By comparison with recombinant proteins, the ratio of rap1A/ras proteins in membranes from HL-60 cells was estimated to be about 4:1. An antiserum directed against the C-terminus of rap2 reacted strongly with recombinant rap2, but not with membranes from tested mammalian cells. In conclusion, rap1A and rap1B proteins are distributed differentially among membranes from various mammalian cell types and are isoprenylated in HL-60 cells

    Bibliometric development of Naunyn–Schmiedeberg’s archives of pharmacology

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    Funding Information: We would like to thank Prof. Dr. Athineos Phillipu (University of Innsbruck, Austria) for his critical reading of the paper and Dr. Detlef Klüber from Springer Nature for supporting this project and stimulating discussions. Publisher Copyright: © 2022, The Author(s).Motivated by the 150-year anniversary of the Naunyn–Schmiedeberg’s Archives of Pharmacology in 2023, we studied the bibliometric development of the journal. We evaluated data from Editorial Reports, Clarivate, and Springer Nature databases. Several parameters representing the journal’s performance, such as the impact factor and social impact, were analyzed over the years. We analyzed the journal’s meta-data and wrote an algorithm to retrieve cities and countries of origin. We could see a decrease in publications from Germany and an increase in papers from Brazil, China, Egypt, and Iran during the last years. The decrease in publications from Germany is probably a zeitgeist effect because this country places a strong emphasis on high-impact factor papers for academic promotion and winning grants. Germany was the country with the most publications throughout the 100 most-cited articles. Most of these articles were published between 1970 and 1990, when neurotransmitters were the most published topic. Klaus Starke (Freiburg) and Manfred Göthert (Bonn) were prominent drivers of this field. The most common topics nowadays are “Drugs for the Treatment of Malignant Tumor Diseases” and “Immunopharmacology.” The internationality of the journal substantially increased after introduction of English as mandatory language in the 1970s. The journal also experienced substantial COVID-19 pandemic-related effects. This paper is not only of relevance for the field of pharmacology but for science in general in the sense that Naunyn–Schmiedeberg’s Archives of Pharmacology is a case study for profound changes in a traditional scientific journal, requiring permanent adjustment by editors, referees, publisher, authors, and readers alike. The development of the journal has been strongly influenced by historic and political developments, cultural attitudes (zeitgeist), language changes, global changes in research topics, and eminent individuals who published many papers in Naunyn–Schmiedeberg’s Archives of Pharmacology.publishe

    Perspective article: A proposal for rational drug class terminology

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    Collective names for drugs were coined for various reasons, some of which we would now recognise as misguided
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