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  • Electronic Resource  (4)
  • 1985-1989  (3)
  • 1970-1974  (1)
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  • Electronic Resource  (4)
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  • 1
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The antitumor action of the 2-chloroethylnitrosocarbamoyl derivatives of peptides related to the 9–13 amino acid residues of α-MSH/ACTH and of the C-terminal tetrapeptide analogue of gastrin have been investigated. Series of 2-chloroethylnitrosoureas attached to amino acids, di-, tri-, tetra-, or pentapeptides were examined in a primary screening system. Among these compounds the Pro-Val-, Lys-Pro-Val-, and Trp-Gly-Lys-Pro-Val-containing 2-chloroethylnitrosocarbamoyl groups were the most effective in the L1210 system. The human melanoma xenograft line was also affected by these agents, while colorectal xenografts were insensitive. A combination of tripeptide-2-chloroethyl-nitrosourea with BCNU induced more than additive growth inhibition of L1210 leukemia.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Gewebeverteilung von C14-markiertem 1,6-Dibrommannit (DBM) und 1,6-Dibromdulcit (DBD) in vivo an Mäusen untersucht. Die in vivo-Gewebekumulation des über eine stärkere cytostatische Wirkung und ein breiteres tumorhemmendes Spektrum verfügenden Dibromdulcit war von größerem Ausmaß als die des Dibrommannit. Der in der intracellulären Kumulationsfähigkeit beider 1,6-Dibromhexite gefundene Unterschied zeigte auch quantitativ gute Übereinstimmung mit den zur Auslösung gleicher biologischer Wirkung benötigten Dosisunterschieden, bzw. gab Aufklärung über die Vertiefung und Spezialisierung der biologischen Wirkungen. In der in vitro-Zellpenetrationsuntersuchung bei den gegenüber Dibromhexiten sensitiven Yoshida, bzw. refraktären S-180-Ascitestumorzellen wurde die Aufnahme des 1-C14- und 1,6-di-Br82-markierten 1,6-Dibrommannit bzw. 1,6-Dibromdulcit untersucht. Von den in der Dibromhexitempfindlichkeit verschiedenen Tumorzellen wurden aus den C14- und Br82-markierten Verbindungen Radiobrom und Radiocarbon in verschiedenem Verhältnis aufgenommen bzw. beständig angebunden. Deshalb ist anzunehmen, daß sich die Biotransformationen beider Dibromhexite im Aufnahmevorgang hauptsächlich hinsichtlich des Spaltungsorts und der Spaltungsgeschwindigkeit ihrer C-Br-Bindungen voneinander unterscheiden.
    Notes: Summary Tissue distribution of C14-labelled 1,6-dibromomannitol (DBM) and 1,6-dibromodulcitol (DBD) was investigated in vivo in mice. The in vivo tissue accumulation of dibromodulcitol possessing a stronger cytostatic effect and broader antitumour spectrum was greater than that of dibromomannitol. The difference between the intracellular accumulation abilities of both 1,6-dibromohexitols showed a good quantitative agreement with the differences of doses required for producing identical biologic actions; thereby intensification and specialisation of the biological effects could be interpreted. The in vitro cell studies of the uptake of 1-C14 and 1,6-di-Br82 labelled 1,6-dibromo-D-mannitol and of 1,6-dibromodulcitol, respectively were mode in Yoshida tumour cells sensitive to dibromohexitols and in S-180 ascites cells resistant to the same drugs. Tumour cells, which were different in their dibromohexitol sensitivities, took up or bound steadily radiocarbon and radiobromine from Br82 and C14-labelled compounds in a different ratio. It was presumable that biotransformations of both dibromohexitols differed in the course of the uptake process, mainly in respect to place and velocity of the decomposition of their C-Br bonds.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-7276
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The glycosaminoglycans (GAGs) of low (LM) and highly metastatic (HM) cell lines of the Lewis lung tumour (3LL) were compared using [3H]glucosamine labelling techniques. The GAGs isolated from nuclei, cytoplasm, pericellular fractions and medium were analysed by cellulose acetate electrophoresis and by digestion with specific enzymes, and the following conclusions were drawn. 1. Increased cellular uptake and incorporation of [3H]glucosamine into glycoconjugates of the cytoplasm was a typical feature of the highly metastatic cell line after a 48-h labelling. However, there was no elevated radioactivity in glycolipids. 2. Radioactivity of the purified GAGs was two and three times higher in nuclear and cytoplasmic fractions of HM cells than in those of LM cells. There was much less difference between the two cell lines in the pericellular fractions. 3. A definite change from chondroitin sulphate to dermatan sulphate dominancy was recorded in each GAG fraction. Higher heparan sulphate labelling was observed in the cytoplasmic and pericellular GAGs of HM cultures. 4. In the post-labelling period about three times more GAG was present in the extracellular compartment of the HM cultures compared with the LM cultures. 5. In the LM cultures the total GAG-associated radioactivity decreased by 73 per cent in the 48-h chase period whereas in the HM cultures it decreased by only 30 per cent. This indicates a higher rate of GAG degradation in the LM cultures.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-7276
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The enhanced metastatic capacity of an in vivo selected Lewis lung tumor line (LLT-HH) was correlated with changes in cell-associated glycosaminoglycans (GAG) using ultrastructural cytochemistry, flow cytometry and biochemistry. The increase in highly sulphated GAG content on the cell membrane of LLT-HH cells compared to the parent LLT cells was demonstrated cytochemically. Using in vitro [3H]glucosamine labelling of GAG components it was shown that the LLT-HH cells were characterized by a high production of heparan sulphate while the parent LLT line had a high hyaluronic acid-chondroitin sulphate production. The high metastatic phenotype is accompanied by an altered production of cell-associated GAGs.
    Type of Medium: Electronic Resource
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