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  • 1
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 67 (1965), S. 176-191 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Two further irritant and cocarcinogenic compounds B1, C37H58O8, and B2, C35H54O8, have been isolated from Croton Oil in the pure state. These compounds are di-esters of the polyfunctional diterpen alcohol C20H28O6 with (+)-S-2-methylbutyric acid and lauric (B1)- and capric acid (B2) respectively. The alcohol C20H28O6 is also the parent alcohol of compound A1 from Croton Oil, as has been demonstrated earlier.
    Notes: Zusammenfassung Aus Crotonöl werden zwei weitere entzündlich und cocarcinogen hoch aktive Wirkstoffe B1, C37H58O8 und B2, C35H54O8 rein dargestellt. Es sind Diester des polyfunktionellen Diterpenalkohols Phorbol C20H28O6 mit (+)-S-2-Methylbuttersäure und Laurin (B1)- bzw. Caprinsäure (B2). Der Alkohol C20H28O6 ist bereits früher als Grundalkohol des Wirkstoffes A1 aus Crotonöl erkannt worden.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 67 (1965), S. 192-204 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Auftrennung der früher beschriebenen Fraktion Bx aus Crotonöl durch Craig-Verteilung führt zu fünf bisher unbekannten entzündlichen und cocarcinogenen Wirkstoffen B3–B7, die rein dargestellt werden. Durch physikalische Methoden wie Massenspektrometrie und NMR-Spektroskopie kombiniert mit chemischen Abbauverfahren wird gezeigt, daß diese Wirkstoffe Diester des polyfunktionellen Diterpenalkohols Phorbol C20H28O6 mit jeweils einer kurzkettigen (Essig-, (+)-S-2-Methylbutter-, Tiglinsäure) und einer langkettigen Fettsäure (Capryl-, Caprin-, Laurinsäure) sind. Die neuen Wirkstoffe werden durch ihre entzündliche und cocarcinogene Wirkung an Mäusen Charakterisiert.
    Notes: Summary Resolution of fraction Bx from Croton Oil by Craig-distribution reveals 5 new irritant and cocarcinogenic compounds B3–B7. By physical methods such as mass-spectrometry and NMR-spectroscopy combined with chemical degradation these compounds are shown to be diesters of the polyfunctional Diterpen alcohol Phorbol C20H28O6 each with a short chain (acetic-, (+)-S-2-methylbutanoic-, tiglic acid) and a long chain fatty acid (octanoic-, decanoic-, dodecanoic acid). The new compounds are being characterized by their irritant and cocarcinogenic activity in mice.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 66 (1965), S. 478-490 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary For systematic fractionation of Croton Oil a separation scheme is described employing multiple distribution and chromatography in combination with suitable biological assays. In a reproducible manner two highly active compounds have been isolated which represent together practically all the toxic, irritant and cocarcinogenic activity of Croton Oil. In thin layer chromatography the resinous compounds show significantly different R f-values but migrate as one single spot respectively. They show very similar physical, chemical and biological properties and represent the most potent cocarcinogens described as yet.
    Notes: Zusammenfassung Es wird ein Trennungsgang zur systematischen Fraktionierung von Crotonöl beschrieben, der unter Anwendung multiplikativer Verteilungs- und chromatographischer Verfahren sowie geeigneter biologischer Teste die Isolierung von zwei hochwirksamen Substanzen A und B in reproduzierbarer Weise ermöglicht. Diese Substanzen enthalten praktisch die gesamte toxische, entzündliche und cocarcinogene Aktivität des Crotonöls. Die beiden harzartigen Wirkstoffe unterscheiden sich signifikant im R f-Wert, wandern aber jeweils als einheitliche Flecken und zeigen sehr ähnliche physikalische, chemische und biologische Eigenschaften. Sie stellen die wirksamsten bisher beschriebenen Cocarcinogene dar.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 65 (1963), S. 325-333 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Biological assays are described for quantitative measurement of the irritant, cocarcinogenic and toxic activity of croton oil. They are suitable as routine methods for following the active principles in the course of the chemical separation process.
    Notes: Zusammenfassung Es werden Teste zur quantitativen Messung der entzündlichen, der cocarcinogenen und der toxischen Wirkung des Crotonöls beschrieben. Sie eignen sich als Routinemethoden zur Verfolgung der wirksamen Prinzipien im Verlauf der chemischen Aufarbeitung des Crotonöls.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1335
    Keywords: Thapsigargin ; Non-TPA-type tumour promoter ; Calcium ATPase inhibitor ; Microsomal fraction ; Specific binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A method is described for measuring rapid, specific, and saturable binding of the skin irritant and tumour-promoting secretagogue thapsigargin (sesquiterpene lactone) to the microsomal fraction from mouse brain. Employing the tritium-labelled compound its apparent dissociation constant,K d, and the maximal amount of bindingB max are shown to be 9.8 nM and 1.9 pmol/mg protein respectively. Such aK d for thapsigargin is similar to (a) its IC50 value for inhibiting Ca2+ uptake in the microsomal fraction from rat brain and (b) its EC50 values for inducing a rise in the cytoplasmic Ca2+ concentration of human platelets and histamine release from rat peritoneal mast cells. A positive correlation is found between the binding affinities of thapsigargin, thapsitranstagin, and trilobolide, their potencies as secretagogues and their lipophilicities. This correlation does not extend to the skin-irritant activities of the compounds thus emphasizing that their mechanism of action is unlike that of 12-O-tetradecanoylphorbol 13-acetate.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 301-306 
    ISSN: 1432-1335
    Keywords: Key words Conditional cancerogens ; Diterpene esters ; Euphorbia factors ; Food chain ; Metabolism of␣tumor promoters in goats ; Poisoning by contaminated fodder ; Pollution of goat's milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Special procedures were developed to investigate poisonous milk of lactating goats fed experimentally on aerial parts of the herb Euphorbia peplus L. In extracts of the milk, weakly irritant in the mouse-ear assay, three diterpene ester toxins were detected by techniques of high-performance liquid chromatography. They are of the ingenane structural type: Euphorbia␣factor Pel (ingenol 20-acetate 3-angelate), Euphorbia factor Pe2 (20-deoxyingenol 3-angelate) and Euphorbia factor␣Pe4 (20-deoxyingenol-6α,7α-epoxide 3-angelate). From goats milk collected 15 days after cessation of the experimental feeding period, extracts were completely free of diterpene ester toxins. The toxins polluting the milk are identical to diterpene ester entities occurring in the aerial parts of E. peplus. Of these, Euphorbia factors Pe1 and Pe2 are known as promoters of tumors of mouse skin. Apart from the toxic Euphorbia factors, the non-toxic parent alcohol ingenol was also detected in the milk. It is absent in the plant, and may have been generated metabolically from a certain portion of the toxic diterpene esters picked up by the goats from their fodder. The results presented here provide, for the first time, data for a novel interpretation of the locally high incidence of esophageal cancer observed in certain areas in the Caspian littoral of Iran, associated with a greater consumption of goat's (and sheep's) milk.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 179-185 
    ISSN: 1432-1335
    Keywords: Key words Conditional cancerogens ; Risk of dietary cancer ; Diterpene esters ; Euphorbia peplus ; Food chain ; Lactating goats ; Polluted milk ; Poisoning by contaminated fodder ; Tumour promoters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lactating goats were fed on aerial parts of the herb Euphorbia peplus L. admixed with their usual green fodder. During the experimental feeding period they showed symptoms of general poisoning. In necropsy the main toxic effects were seen in the heart, lung and liver. Histopathological examinations revealed that the primary toxic effects originated from degenerative changes in parenchymal and endothelial cells. Adverse symptoms in the liver and kidney were also reflected in an alteration of the levels of certain serum enzymes and of blood urea nitrogen. The milk of the goats fed on E. peplus, consumed by their young kids, caused poisoning and even death, with signs similar to those observed in the adult dams. These observations support the hypothesis that the poisoning observed in both milk-raised kids and mother goats is caused by diterpene ester type toxins present in the aerial parts of the herb contaminating the dams fodder. Generally, such skin irritant and hyperplasiogenic toxins are known to be highly active tumour promoters of skin and other organ, e.g. in mice. Lactating goats – as an important source of milk around the world – in a setting similar to that described, may provide a valid experimental etiological model for investigation of food polluted by tumour-promoting diterpene ester toxins.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 106 (1983), S. 71-73 
    ISSN: 1432-1335
    Keywords: Arylhydrocarbon monooxygenase ; Specific gene activation ; Human epithelial cells (HeLa) ; Arylhydrocarbons ; Diterpene esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Arylhydrocarbons are inducers of monooxygenase activity in epithelial cells in culture (Hela) whereas diterpene esters are not. This is one more example of a specific biochemical difference — here in gene activation — exhibited by tumor initiators and tumor promoters of the classes of compounds assayed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 272 (1978), S. 373-375 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Induction of EBV antigen synthesis in a P3HR-I (), B95-8 () cells by TPA. 5 x 105 cells per ml were incubated with 20 ng TPA per ml. Small samples were collected every 24 h after TPA addition and assayed for the % of viral antigen-positive cells according to the procedure of Henle and ...
    Type of Medium: Electronic Resource
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