Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D01453 (caffeine)
 21,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The method of DNA alkaline elution was applied to a study of the formation and resealing of DNA single-strand breaks after irradiation of human fibroblasts with ultraviolet light (UV). The general features of the results were consistent with current concepts of DNA excision repair, in that breaks appeared rapidly after UV, and resealed slowly in normal fibroblasts, whereas breaks did not appear in those cells of patients with xeroderma pigmentosum (XP) that are known to have defects in DNA repair synthesis. The appearance of breaks required a short post-UV incubation, consistent with the expected action of an endonuclease. Cells of the variant form of XP characterized by normal DNA repair synthesis exhibited normal production of breaks after UV, but were slower than normal cells in resealing these breaks. This difference was enhanced by caffeine. A model is proposed to relate this finding with a previously described defect in post-replication repair in these XP variant cells. DNA crosslinking appears to cause an underestimate in the measurement of DNA breakage after UV.
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PMID:DNA single-strand breaks during repair of UV damage in human fibroblasts and abnormalities of repair in xeroderma pigmentosum. 0 51

In anesthetized dogs given secretin intravenously in doses doubling every 60 min and ranging from 0.5 to 8 units per kg body weight per hr, cyclic-AMP levels in pancreatic tissue rose continuously, whereas DNA concentrations were slightly decreased. Bicarbonate concentrations and bicarbonate outputs, cyclic-AMP tissue concentrations and bicarbonate outputs, as well as cyclic-AMP tissue concentrations and juice outputs, were significantly correlated. In conscious pancreatic fistula dogs, there was also a significant correlation between cyclic-AMP and bicarbonate concentrations and outputs in the pancreatic juice after stimulation by exogenous secretin. Accordingly, enhanced release of endogenous secretin achieved by intraduodenal acidification led to a dose-dependent increase in bicarbonate and cyclic-AMP outputs in both conscious and anesthetized dogs. Phosphodiesterase inhibitors (aminophylline, caffeine, and papaverine) given alone to the conscious dogs did not initiate pancreatic bicarbonate secretion, but they potentiated bicarbonate responses to exogenous secretin. These data suggest that cyclic-AMP plays a part in secretin-stimulated pancreatic secretion.
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PMID:Cyclic-AMP and pancreatic bicarbonate secretion in response to secretin in dogs. 0 97

The activity of Aspergillus orzae nuclease S1 on DNA has been investigated under varying pH and metal ion conditions. Nuclease S1 was found to preferentially digest denatured DNA. With native DNA as substrate the enzyme could only digest the DNA when caffeine was added to the reaction mixture. The enzyme was more active in sodium acetate buffer (pH 4.5), than in either standard saline citrate (PH 7.0) or sodium phosphate buffer (pH 6.8). Caffeine was also found to affect the thermal stability of DNA, resulting in a melting profile characterized by two transitions. The first transition (poorly defined) was below the normal melting temperature of the DNA, while the next transition was at the normal melting temperature of the DNA, while the next transition was at the normal melting temperature of the DNA. The susceptibility of caffeine-treated DNA to nuclease digestion seems to be a result of the local unwinding that caffeine causes in the regions of DNA that melt in the first transition. This selective destabilization presumably sensitizes the unwound regions to nuclease hydrolysis. The hydrolysates of the DNA digested by nuclease S1 were subjected first to ion exchange chromatography followed by paper chromatography. The results from this partial characterization of the digestion products showed that they contain mononucleotides as well as oligonucleotides of varying lengths. The base composition of the mononucleotide digests suggests that caffeine has greater preference for interacting with A-T base-pairs in DNA.
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PMID:Caffeine enhancement of digestion of DNA by nuclease S1. 0 67

Four examples (Methamphetamine, Testosterone, Caffeine, Cysteamine) have demonstrated that the response of the organism to a drug is primarily dependent upon the functional status of the organ concerned. If this functional status changes with age, then accordingly the reaction to the drug also changes. If, however, one alters the functional status of an organ in the elderly organism, e.g. inducing increased production of DNA in the liver by partial hepatectomy, the reaction of the organ now follows a pattern comparable to the juvenile organism, rather than being dependent on chronological age.
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PMID:[The correlations between aging and drug effects (author's transl)]. 1 38

Bleomycin (10-(6) M) has been tested in Allium cepa L. meristems which are formed by a proliferating cell population growing under steady state conditions. Chromosome breaks were apparently induced by the antibiotic in cells in G2 period since anaphases with chromatid breaks were formed at a time shorter than G2 + prophase duration. Stimulation of entrance of G2 cells into mitosis is suggested both by an increase in the frequency of early prophases and by the study of waves of prophases in a synchronous subpopulation labelled by caffeine. Progression of other mitotic phases was unaffected. Nucleologenesis rate was increased by the antibiotic in a fashion resembling protein synthesis inhibitors. Protein synthesis is inhibited by 10-(6) M bleomycin to the same extent as 4 X 10(-6) M anisomycin. Both facts suggest that bleomycin has a direct inhibitory effect on protein synthesis in meristems. Given the nucleologenesis sensitivity to nucleolar RNA inhibition it is suggested that the antibiotic activity on nucleolar transcription is mediated through DNA.
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PMID:Action of bleomycin on proliferating plant cells. 6 55

Bleomycin (BLM), an antibiotic obtained from Streptomyces verticillus, is of significance as an antineoplastic agent. The compound is actually the mixture of some 200 related forms which differ from each other in the amine moiety. The drug, at low concentrations, can cause elimination of bases, particularly thymine. This causes strand breakage of DNA and inhibition of cell growth. The influence of BLM on cell growth may be unrelated to the effects on DNA. In general, mitotically dividing cells show more DNA damage than non-dividing cells. G2 seems to be the most sensitive phase indicating that cell death may not be related to a direct effect of BLM on DNA replication. The antibiotic shows specific effects on chromatin and causes chromosomal damage in all sub-phases of interphase. It can affect early prophase chromosomes also. Suggestion has been made that BLM-induced breakage and cell death are similar to those induced by densely ionizing radiations. Whereas the antibiotic affects the frequency of somatic crossing over and produces micronuclei, the data on mutation induction and production of sister-chromatid exchanges do not permit classifying BLM as a potent inducer of these phenomena. The genetic effects of BLM can be modified quantitatively by thiol compounds, caffeine, hyperthermia and H2O2. It is concluded that the available data do not permit assessment of genetic damage in the offsprings of BLM-treated patients. Such studies are urgently needed, as are the studies to find out the effects of BLM on meiotic phenomena.
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PMID:Genetic toxicology of bleomycin. 8 55

The influence of UV-light on DNA-membrane complex (DMC) of Bacillus subtilis was studied. An increased DNA content in DMC for strains 168 and rec A-, and a degradation of DMC for strain polA- have been registrated. The increase in DNA in DMC of the two former strains is inhibited by caffeine to be correlated with changes in protein content in DMC, determined by a radioactive label, but not with lipid content. Thus, the association of DNA with the membrane is mediated by proteins. DNA increasing capacity seen in DMC after UV-irradiation and after the following incubation of bacteria in the complete medium is correlated with a relative sensitivity of strains. To explain these data, it is supposed that the reparative synthesis is accomplished in cell on their membranes and that for the normal completion of DNA repair the association between DNA and the membrane is necessary.
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PMID:[Effect of UV radiation on the DNA-membrane complex of Bacillus subtilis]. 11 19

In an attempt to quantitate DNA repair induced by Neocarzinostatin, the incorporation of labeled thymidine into the human peripheral lymphocytes after exposure to the agent was studied by autoradiography. The exposure of lymphocytes to Neocarzinostatin for 60 min at the concentrations as low as 0.05 mug/ml caused a significant increase in the number of grains per cell within 2 hr of incubation with 10 muCi/ml of 3H-thymidine in the presence of 2mM of hydroxyurea. The number of grains increased with the increasing dose of the agent up to the concentration of around 2.5 mug/ml and then fell at higher concentrations. The extent of maximum incorporation induced by Neocarzinostatin was found to be almost comparable to that induced by 100 erg/mm2 of UV irradiation. Hydroxyurea or caffeine in the labeling medium showed little or no effect on the grain count, but acriflavine at 0.1 mM reduced the grain count by a factor of about 6. These results indicate that relatively high level of repair synthesis occurred in human lymphocytes after exposure to Neocarzinostatin and provide further evidence for the direct damage of cellular DNA induced by the antibiotic.
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PMID:Unscheduled DNA synthesis in human lymphocytes treated with neocarzinostatin. 12 91

The caffeine potentiation on lethality of L-1210 cells treated with Neocarzinostatin was studied. Colony formation of L-1210 cells treated with Neocarzinostatin was significantly decreased by incubation of the cells for 48 hr with 0.5 mM of caffeine which alone did not affect the growth rate and colony-forming ability of the cells. These results indicate that Neocarzinostatin may induce repairable damage in DNA of L-1210 cells.
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PMID:Caffeine potentiation on lethality of L-1210 cells treated with neocarzinostatin. 13 61

Incubation of Chinese hamster cells with labelled caffeine leads to transfer of radioactivity to DNA. This association occurs during the S phase of the cell cycle and involves parental as well as newly synthesised strands. The replacement of thymidine by BrdUrd prevents the incorporation radioactivity from caffeine into the DNA strands containing BrdUrd. Thymine is the only base which becomes labelled and data suggesting the participation of methyl groups of caffeine in the biosynthesis of thymine are presented. Ultraviolet irradiation increases the incorporation of radioactivity from caffeine to DNA.
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PMID:Interaction of caffeine with the DNA of Chinese hamster cells. 13 27


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