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Drug
Enzyme
Compound
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Target Concepts:
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Query: UMLS:C0034069 (
pulmonary fibrosis
)
7,050
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In the present study the fibrogenic potential of intact bleomycins as well as their acetyldipeptide and terminal polyamine constituents have been assessed. Administration of
Blenoxane
, bleomycin A2, or bleomycin B2 to rats produced histopathologic evidence of
pulmonary fibrosis
when tissues were examined 28 days following a single intratracheal dose. These compounds also produced a readily detectable increase in pulmonary collagen synthesis as evidenced by an approximate twofold increase over control values in the formation of [3H]hydroxyproline in an in vitro lung mince system. Lung collagen synthetic activity remained significantly elevated over control values for up to 2 weeks. However, neither the acetyldipeptides nor the polyamine constituents of bleomycin A2 and B2 produced detectable increases in lung collagen synthesis or in histopathologic evidence of pulmonary injury. Spermine and spermidine, the terminal amine components associated with bleomycin-A6 and with tallysomycin A, tallysomycin B, and bleomycin-A5, respectively, did produce significant pulmonary fibrotic injury in rats following intratracheal administration. Out of an extensive series of polyamines, bleomycin acetyldipeptides and intact bleomycin and tallysomycin analogs, only spermine and spermidine were found to produce hydrogen peroxide and acrolein upon incubation in vitro with amine oxidase, a common pulmonary enzyme. Conclusions regarding the relative toxicity of different bleomycin analogs based solely on the toxicity produced by administration of their terminal amine constituent must therefore be made with caution.
...
PMID:Fibrogenic structure-activity study of the bleomycin molecule. 619 69
The antibiotics known as bleomycins constitute a family of natural products clinically employed for the treatment of a wide spectrum of cancers. The drug acts as an antitumor agent by virtue of the ability of a metal complex of the antibiotic to cleave DNA. Bleomycins are differentiated by their C-terminal regions. Previous structural studies involving metal-bleomycin-DNA triads have allowed the identification of the bithiazole-(C-terminus substituent) segment in this molecule as the one that most closely interacts with DNA. Three different modes of binding of metallo-bleomycins to DNA (partial or total intercalation of the bithiazole unit between DNA bases, or binding to the minor groove) have been proposed in the literature. The therapeutic use of bleomycin is frequently associated with the development of
pulmonary fibrosis
. The severity of this side effect has been attributed to the C-terminus of the antibiotic by some researchers. The degree of pulmonary toxicity of bleomycin-A
2
and -A
5
, were found to be higher than those of bleomycin-B
2
and peplomycin. Since the introduction of
Blenoxane
to clinical medicine in 1972, attempts have been made at modifying the basic bleomycin structure at the C-terminus to improve its therapeutic index. However, the pharmacological and toxicological importance of particular C-termini on bleomycin remains unclear. The present study was designed to determine the effect of Zn(II)bleomycin-A
2
, -A
5
, -B
2
, and Zn(II)peplomycin on the structure of a DNA hairpin containing the 5'-GC-3' binding site. We provide evidence that different Zn(II)bleomycins affect the structure of the tested DNA segment in different fashions.
...
PMID:NMR study of the effects of some bleomycin C-termini on the structure of a DNA hairpin with the 5'-GC-3' binding site. 2785 65
