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Antimicrobial Agents and Chemotherapy Jul 1999Abacavir (1592U89), a nucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type-1 (HIV-1), has been evaluated for... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
Single-dose pharmacokinetics and safety of abacavir (1592U89), zidovudine, and lamivudine administered alone and in combination in adults with human immunodeficiency virus infection.
Abacavir (1592U89), a nucleoside reverse transcriptase inhibitor with in vitro activity against human immunodeficiency virus type-1 (HIV-1), has been evaluated for efficacy and safety in combination regimens with other nucleoside analogs, including zidovudine (ZDV) and lamivudine (3TC). To evaluate the potential pharmacokinetic interactions between these agents, 15 HIV-1-infected adults with a median CD4(+) cell count of 347 cells/mm3 (range, 238 to 570 cells/mm3) were enrolled in a randomized, seven-period crossover study. The pharmacokinetics and safety of single doses of abacavir (600 mg), ZDV (300 mg), and 3TC (150 mg) were evaluated when each drug was given alone or when any two or three drugs were given concurrently. The concentrations of all drugs in plasma and the concentrations of ZDV and its 5'-glucuronide metabolite, GZDV, in urine were measured for up to 24 h postdosing, and pharmacokinetic parameter values were calculated by noncompartmental methods. The maximum drug concentration (Cmax), the area under the concentration-time curve from time zero to infinity (AUC0-infinity), time to Cmax (Tmax), and apparent elimination half-life (t1/2) of abacavir in plasma were unaffected by coadministration with ZDV and/or 3TC. Coadministration of abacavir with ZDV (with or without 3TC) decreased the mean Cmax of ZDV by approximately 20% (from 1.5 to 1.2 microg/ml), delayed the median Tmax for ZDV by 0.5 h, increased the mean AUC0-infinity for GZDV by up to 40% (from 11.8 to 16.5 microg. h/ml), and delayed the median Tmax for GZDV by approximately 0.5 h. Coadministration of abacavir with 3TC (with or without ZDV) decreased the mean AUC0-infinity for 3TC by approximately 15% (from 5.1 to 4.3 microg. h/ml), decreased the mean Cmax by approximately 35% (from 1.4 to 0.9 microg/ml), and delayed the median Tmax by approximately 1 h. While these changes were statistically significant, they are similar to the effect of food intake (for ZDV) or affect an inactive metabolite (for GZDV) or are relatively minor (for 3TC) and are therefore not considered to be clinically significant. No significant differences were found in the urinary recoveries of ZDV or GZDV when ZDV was coadministered with abacavir. There was no pharmacokinetic interaction between ZDV and 3TC. Mild to moderate headache, nausea, lymphadenopathy, hematuria, musculoskeletal chest pain, neck stiffness, and fever were the most common adverse events reported by those who received abacavir. Coadministration of ZDV or 3TC with abacavir did not alter this adverse event profile. The three-drug regimen was primarily associated with gastrointestinal events. In conclusion, no clinically significant pharmacokinetic interactions occurred between abacavir, ZDV, and 3TC in HIV-1-infected adults. Coadministration of abacavir with ZDV or 3TC produced mild changes in the absorption and possibly the urinary excretion characteristics of ZDV-GZDV and 3TC that were not considered to be clinically significant. Coadministration of abacavir with ZDV and/or 3TC was generally well tolerated and did not produce unexpected adverse events.
Topics: Adolescent; Adult; Anti-HIV Agents; Cross-Over Studies; Dideoxynucleosides; Drug Therapy, Combination; Female; HIV Infections; Humans; Lamivudine; Male; Middle Aged; Zidovudine
PubMed: 10390227
DOI: 10.1128/AAC.43.7.1708 -
Revista Da Associacao Medica Brasileira... Nov 2021Reactive oxygen species and oxygen free radicals cause oxidative damage to lipids, proteins, and cell DNA in the cell membrane. Although many DNA products are produced...
OBJECTIVE
Reactive oxygen species and oxygen free radicals cause oxidative damage to lipids, proteins, and cell DNA in the cell membrane. Although many DNA products are produced during oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine (8-OHdG) is the most common one, since it can be produced in in vivo environment. In recent years, diving has been done quite frequently for business and sports purposes all over the world. Increased environmental pressure in diving leads to hyperoxia and causes oxidative stress.
METHODS
The acute effects of diving on DNA damage were evaluated by comparing 8-hydroxy-2'-deoxyguanosine values of 15 professional diver groups before and after diving. In addition to the demographic characteristics, the serum 8-hydroxy-2'-deoxyguanosine levels of these 15 divers were compared with the control group consisting of nondiving medical students to examine the chronic effect of diving on DNA damage.
RESULTS
After deep dive, the amount of 8-hydroxy-2'-deoxyguanosine increased significantly in the diver group and acute DNA damage was observed (T1: 38.86±4.7; T2: 51.77±4.53; p<0.05). In the control group, the amount of 8-hydroxy-2'-deoxyguanosine was insignificant (C1: 47.48±3.73; T1: 38.86±4.7; p>0.05).
CONCLUSIONS
It was found that air dives caused an increase in serum 8-hydroxy-2'-deoxyguanosine levels, leading to acute oxidative stress and aging. However, there is no chronic side effect, according to the study of samples taken from the control group. This was thought to be due to the relative sedentary life of the control group. The duration of the effect or the ability to return to normal values should be investigated with further studies planned with large populations.
Topics: 8-Hydroxy-2'-Deoxyguanosine; Biomarkers; DNA Damage; Deoxyguanosine; Humans; Oxidative Stress; Reactive Oxygen Species
PubMed: 34909901
DOI: 10.1590/1806-9282.20210748 -
Analytical Chemistry Dec 2018A wide spectrum of DNA lesions can be generated from byproducts of endogenous metabolism and/or from environmental exposure. A DNA adductomic approach for the robust...
A wide spectrum of DNA lesions can be generated from byproducts of endogenous metabolism and/or from environmental exposure. A DNA adductomic approach for the robust quantification of DNA adducts in cellular and tissue DNA may facilitate the use of DNA adducts for biomonitoring studies and enable comprehensive assessment about DNA repair. Normalized retention time (iRT) has been widely used in scheduled selected-reaction monitoring (SRM) methods for highly sensitive and high-throughput analyses of protein samples in complicated matrices. By using a similar method, we established the iRT scores for 36 modified nucleosides from the retention times of the four canonical 2'-deoxynucleosides on a nanoflow liquid chromatography-nanospray ionization-tandem mass spectrometry (nLC-NSI-MS/MS) system. The iRT scores facilitated reliable prediction of retention time and were employed for establishing a scheduled SRM method for quantitative assessment of a subset of the DNA adductome. The quantification results of the scheduled SRM method were more accurate and precise than those from an unscheduled method.
Topics: Chromatography, High Pressure Liquid; DNA Adducts; Deoxyadenosines; Deoxycytidine; Deoxyguanosine; Hydrophobic and Hydrophilic Interactions; Nanotechnology; Stereoisomerism; Tandem Mass Spectrometry; Thymidine
PubMed: 30500177
DOI: 10.1021/acs.analchem.8b04660 -
Synthesis and nonenzymatic template-directed polymerization of 2'-amino-2'-deoxythreose nucleotides.Journal of the American Chemical Society Feb 2014Threose nucleic acid (TNA) is a potential alternative genetic material that may have played a role in the early evolution of life. We have developed a novel synthesis of...
Threose nucleic acid (TNA) is a potential alternative genetic material that may have played a role in the early evolution of life. We have developed a novel synthesis of 2'-amino modified TNA nucleosides (2'-NH2-TNA) based on a cycloaddition reaction between a glycal and an azodicarboxylate, followed by direct nucleosidation of the cycloadduct. Using this route, we synthesized the thymine and guanine 2'-NH2-TNA nucleosides in seven steps with 24% and 12% overall yield, respectively. We then phosphorylated the guanine nucleoside on the 3'-hydroxyl, activated the phosphate as the 2-methylimidazolide, and tested the ability of the activated nucleotide to copy C4 RNA, DNA, and TNA templates by nonenzymatic primer extension. We measured pseudo-first-order rate constants for the first nucleotide addition step of 1.5, 0.97, and 0.57 h(-1) on RNA, DNA, and TNA templates, respectively, at pH 7.5 and 4 °C with 150 mM NaCl, 100 mM N-(hydroxylethyl)imidazole catalyst, and 5 mM activated nucleotide. The activated nucleotide hydrolyzed with a rate constant of 0.39 h(-1), causing the polymerization reaction to stall before complete template copying could be achieved. These extension rates are more than 1 order of magnitude slower than those for amino-sugar ribonucleotides under the same conditions, and copying of the TNA template, which best represented a true self-copying reaction, was the slowest of all. The poor kinetics of 2'-NH2-TNA template copying could give insight into why TNA was ultimately not used as a genetic material by biological systems.
Topics: Crystallography, X-Ray; Cycloaddition Reaction; Deoxyribonucleosides; Hydrolysis; Molecular Structure; Templates, Genetic; Tetroses
PubMed: 24409991
DOI: 10.1021/ja411950n -
Nucleic Acids Research Feb 2003The deamination of nucleobases in DNA occurs by a variety of mechanisms and results in the formation of hypoxanthine from adenine, uracil from cytosine, and xanthine and...
The deamination of nucleobases in DNA occurs by a variety of mechanisms and results in the formation of hypoxanthine from adenine, uracil from cytosine, and xanthine and oxanine from guanine. 2'-Deoxyxanthosine (dX) has been assumed to be an unstable lesion in cells, yet no study has been performed under biological conditions. We now report that dX is a relatively stable lesion at pH 7, 37 degrees C and 110 mM ionic strength, with a half-life (t(1/2)) of 2.4 years in double-stranded DNA. The stability of dX as a 2'-deoxynucleoside (t(1/2) = 3.7 min at pH 2; 1104 h at pH 6) was increased substantially upon incorporation into a single-stranded oligodeoxynucleotide, in which the half-life of dX at different pH values was found to range from 7.7 h at pH 2 to 17 700 h at pH 7. Incorporation of dX into a double-stranded oligodeoxynucleotide resulted in a statistically insignificant increase in the half-life to 20 900 h at pH 7. Data for the pH dependence of the stability of dX in single-stranded DNA were used to determine the rate constants for the acid-catalyzed (2.6 x 10(-5) x s(-1)) and pH-independent (1.4 x 10(-8) x s(-1)) depurination reactions for dX as well as the dissociation constant for the N7 position of dX (6.1 x 10(-4) M). We conclude that dX is a relatively stable lesion that could play a role in deamination-induced mutagenesis.
Topics: Amination; DNA; Deoxyribonucleosides; Half-Life; Hydrogen-Ion Concentration; Kinetics; Models, Chemical; Oligodeoxyribonucleotides
PubMed: 12560502
DOI: 10.1093/nar/gkg177 -
Acta Biochimica Polonica 2015Methylation at position 5 of cytosine (Cyt) at the CpG sequences leading to formation of 5-methyl-cytosine (m(5)Cyt) is an important element of epigenetic regulation of...
Methylation at position 5 of cytosine (Cyt) at the CpG sequences leading to formation of 5-methyl-cytosine (m(5)Cyt) is an important element of epigenetic regulation of gene expression. Modification of the normal methylation pattern, unique to each organism, leads to the development of pathological processes and diseases, including cancer. Therefore, quantification of the DNA methylation and analysis of changes in the methylation pattern is very important from a practical point of view and can be used for diagnostic purposes, as well as monitoring of the treatment progress. In this paper we present a new method for quantification of 5-methyl-2'deoxycytidine (m(5)C) in the DNA. The technique is based on conversion of m(5)C into fluorescent 3,N(4)-etheno-5-methyl-2'deoxycytidine (εm(5)C) and its identification by reversed-phase high-performance liquid chromatography (RP-HPLC). The assay was used to evaluate m(5)C concentration in DNA of calf thymus and peripheral blood of cows bred under different conditions. This approach can be applied for measuring of 5-methylcytosine in cellular DNA from different cells and tissues.
Topics: Animals; Calibration; Cattle; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; DNA; DNA Methylation; Deoxycytidine; Female; Limit of Detection; Molecular Biology; Phosphorus Radioisotopes
PubMed: 26098716
DOI: 10.18388/abp.2015_988 -
Bioorganic Chemistry Nov 2019Mitomycin C (MC), an anti-cancer drug, and its analog, decarbamoylmitomycin C (DMC), are DNA-alkylating agents. MC is currently used in the clinics and its cytotoxicity...
Mitomycin C (MC), an anti-cancer drug, and its analog, decarbamoylmitomycin C (DMC), are DNA-alkylating agents. MC is currently used in the clinics and its cytotoxicity is mainly due to its ability to form Interstrand Crosslinks (ICLs) which impede DNA replication and, thereby, block cancer cells proliferation. However, both MC and DMC are also able to generate monoadducts with DNA. In particular, we recently discovered that DMC, like MC, can form deoxyadenosine (dA) monoadducts with DNA. The biological role played by these monoadducts is worthy of investigation. To probe the role of these adducts and to detect them in enzymatic digests of DNA extracted from culture cells treated by both drugs, we need access to reference compounds i.e. MC and DMC dA-mononucleoside adducts. Previous biomimetic methods used to generate MC and DMC mononucleoside adducts are cumbersome and very low yielding. Here, we describe the diastereospecific chemical synthesis of both C-1 epimers of MC and DMC deoxyadenosine adducts. The key step of the synthesis involves an aromatic substitution reaction between a 6-fluoropurine 2'-deoxyribonucleoside and appropriately protected stereoisomeric triaminomitosenes to form protected-MC-dA adducts with either an S or R stereochemical configuration at the adenine-mitosene linkage. Fluoride-based deprotection methods generated the final four reference compounds: the two stereoisomeric MC-dA adducts and the two stereoisomeric DMC-dA adducts. The MC and DMC-dA adducts synthesized here will serve as standards for the detection and identification of such adducts formed in the DNA of culture cells treated with both drugs.
Topics: Alkylation; DNA Adducts; Deoxyadenosines; Fungal Proteins; Mitomycin; Mitomycins; Molecular Conformation; Single-Strand Specific DNA and RNA Endonucleases; Stereoisomerism
PubMed: 31539740
DOI: 10.1016/j.bioorg.2019.103280 -
Genetics Jul 2022Determining mutation signatures is standard for understanding the etiology of human tumors and informing cancer treatment. Multiple determinants of DNA replication...
Determining mutation signatures is standard for understanding the etiology of human tumors and informing cancer treatment. Multiple determinants of DNA replication fidelity prevent mutagenesis that leads to carcinogenesis, including the regulation of free deoxyribonucleoside triphosphate pools by ribonucleotide reductase and repair of replication errors by the mismatch repair system. We identified genetic interactions between rnr1 alleles that skew and/or elevate deoxyribonucleoside triphosphate levels and mismatch repair gene deletions. These defects indicate that the rnr1 alleles lead to increased mutation loads that are normally acted upon by mismatch repair. We then utilized a targeted deep-sequencing approach to determine mutational profiles associated with mismatch repair pathway defects. By combining rnr1 and msh mutations to alter and/or increase deoxyribonucleoside triphosphate levels and alter the mutational load, we uncovered previously unreported specificities of Msh2-Msh3 and Msh2-Msh6. Msh2-Msh3 is uniquely able to direct the repair of G/C single-base deletions in GC runs, while Msh2-Msh6 specifically directs the repair of substitutions that occur at G/C dinucleotides. We also identified broader sequence contexts that influence variant profiles in different genetic backgrounds. Finally, we observed that the mutation profiles in double mutants were not necessarily an additive relationship of mutation profiles in single mutants. Our results have implications for interpreting mutation signatures from human tumors, particularly when mismatch repair is defective.
Topics: Humans; Deoxyribonucleosides; DNA Mismatch Repair; DNA Repair; DNA-Binding Proteins; Mutation; MutS Homolog 2 Protein; MutS Proteins; Ribonucleotide Reductases; Saccharomyces cerevisiae Proteins; Substrate Specificity
PubMed: 35686905
DOI: 10.1093/genetics/iyac092 -
Environmental Health Perspectives Oct 1994Facile aerial oxidation is a general feature of guanine ribo- and 2'-deoxyribonucleosides that are substituted at the 8-position by an aminoaryl group. In previous work,... (Review)
Review
Facile aerial oxidation is a general feature of guanine ribo- and 2'-deoxyribonucleosides that are substituted at the 8-position by an aminoaryl group. In previous work, it had been suggested that two of the major oxidation products are a pair of diastereomers having a spiro structure. These were presumed to be related by a chiral difference at the spiro carbon atom. The pattern of the oxidative process involves a contraction of the pyrimidine ring. It was thought to be analogous to that suggested by other investigators for the oxidation of uric acid, but for which no really definitive evidence had been presented. We have been able now to isolate in a crystalline state one of the diastereomers produced by the aerial oxidation of 8-phenylaminoguanosine under alkaline conditions. Analysis by X-ray diffraction has now confirmed the type of spiro structure promulgated previously. These findings also imply that spiro compounds are likely to be produced during the aerial oxidation of any 8-arylaminoguanine nucleoside or 2'-deoxynucleoside. In addition, this work adds considerable weight to the results of Poje and Sokolic-Maravic who proposed that a spiro intermediate is produced during the aerial oxidation of uric acid (12,13). However, they found this compound to be unstable to base, in contrast to the arylaminoguanine oxidation products. In the course of the above work we showed that the 8-arylamino derivatives of guanosine can be converted by the Barton deoxygenation method to the corresponding 2'-deoxyribonucleosides. This makes available a number of the latter compounds, which are not easily prepared by other methods.
Topics: DNA Adducts; Deoxyguanosine; Guanosine; Models, Molecular; Molecular Structure; Oxidation-Reduction; Structure-Activity Relationship
PubMed: 7889837
DOI: 10.1289/ehp.94102s6143 -
Antiviral Chemistry & Chemotherapy 2007Existing nucleoside reverse transcriptase inhibitors for HIV disease are limited by problems of resistance and, in some cases, long-term toxicity. Apricitabine (ATC;... (Review)
Review
Existing nucleoside reverse transcriptase inhibitors for HIV disease are limited by problems of resistance and, in some cases, long-term toxicity. Apricitabine (ATC; formerly BCH10618, SPD754 and AVX754) is a deoxycytidine analogue nucleoside reverse transcriptase inhibitor in clinical development. ATC retains substantial in vitro activity against HIV-1 containing many mutations associated with nucleoside reverse transcriptase inhibitor resistance, showing a less than twofold reduction in susceptibility in the presence of either up to five thymidine analogue mutations or the M184V mutation. ATC showed a low potential for cellular or mitochondrial toxicity in vitro. ATC is well absorbed orally, with a bioavailability of 65-80%. Its plasma elimination half-life (approximately 3 h), and the intracellular half-life of its triphosphate (TP) metabolite (6-7 h) support twice-daily dosing. Intracellular ATC-TP levels are markedly reduced in the presence of lamivudine or emtricitabine, indicating that clinical co-administration of ATC together with these agents will not be possible. The drug is renally eliminated, giving a low potential for hepatic drug interactions. In a double-blind, randomized, placebo-controlled Phase II monotherapy trial in antiretroviral-naive patients, ATC doses of 1,200 and 1,600 mg/day reduced plasma viral load levels by 1.65 and 1.58 log10 HIV RNA copies/ml, respectively, after 10 days of treatment (P<0.0001 versus placebo). ATC showed a low propensity to select for resistance mutants in vitro and during clinical monotherapy. ATC was well tolerated in volunteers and in HIV-infected patients. This promising profile suggests that ATC may be useful in treating patients who have failed previous lamivudine- or emtricitabine-containing regimens. Further studies to evaluate the long-term efficacy and tolerability of ATC are underway.
Topics: Anti-HIV Agents; Deoxycytidine; Drug Resistance, Viral; HIV Infections; Humans
PubMed: 17542150
DOI: 10.1177/095632020701800201