Emission kinetics of fluorescent nucleoside analogs

1998 ◽  
Author(s):  
Edward L. Rachofsky ◽  
Larry C. Sowers ◽  
Mary E. Hawkins ◽  
Frank M. Balis ◽  
William R. Laws ◽  
...  
Keyword(s):  
Nucleoside Analogs ◽  
Fluorescent Nucleoside ◽  
Kinetics Of

Synthesis and Hybridization Studies of Oligonucleotide Sequences with Modified Fluorescent Nucleoside Analogs

1998 ◽  
Vol 17 (9-11) ◽  
pp. 1937-1948 ◽  
Author(s):  
Rajendra KPandey ◽  
Snehlata Tripathi ◽  
Krishna Misra
Keyword(s):  
Nucleoside Analogs ◽  
Fluorescent Nucleoside

scholarly journals Synthesis of fluorescent nucleoside analogs as probes for 2′-deoxyribonucleoside kinases

2010 ◽  
Vol 20 (3) ◽  
pp. 841-843 ◽  
Author(s):  
Yongfeng Li ◽  
Priti B. Soni ◽  
Lingfeng Liu ◽  
Xiao Zhang ◽  
Dennis C. Liotta ◽  
...  
Keyword(s):  
Nucleoside Analogs ◽  
Fluorescent Nucleoside ◽  
Deoxyribonucleoside Kinases

scholarly journals In vitro release of cytotoxic nucleoside analogs from lactide-caprolactone and lactide-glycolide copolymers.

2002 ◽  
Vol 49 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Tomasz Kryczka ◽  
Maciej Bero ◽  
Janusz Kasperczyk ◽  
Piotr Dobrzyński ◽  
Barbara Marciniec ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Gamma Radiation ◽  
Local Treatment ◽  
In Vitro Release ◽  
Nucleoside Analogs ◽  
Further Development ◽  
Kinetics Of ◽  
Vitro Release ◽  
Observation Period

The aims of our study were to assess the release of cytotoxic nucleoside analogs 5-fluorouracil and 2-chloro-2'-deoxyadenosine from different lactide-glycolide or lactide-caprolactone biodegradable copolymers and the effects of sterilization on this release. The polymers were sterilized either with ethylene oxide at 37 degrees C, or with gamma radiation (15 kGy, 20 kGy, or 25 kGy). The kinetics of nucleoside release from the copolymers were measured over 50 days. Four copolymers exhibited relatively constant release of nucleosides in micromolar concentrations during the entire observation period. Sterilization with either ethylene oxide or gamma radiation only slightly influenced nucleoside release. Further development of these copolymers as an intracerebral nucleoside delivery system for local treatment of brain tumors is indicated.

scholarly journals Exonuclease Removal of Dideoxycytidine (Zalcitabine) by the Human Mitochondrial DNA Polymerase

2007 ◽  
Vol 52 (1) ◽  
pp. 253-258 ◽  
Author(s):  
Jeremiah W. Hanes ◽  
Kenneth A. Johnson
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Tight Binding ◽  
Nucleoside Analogs ◽  
Physiological Concentration ◽  
Human Mitochondrial Dna ◽  
Immunodeficiency Virus ◽  
Mitochondrial Dna Polymerase ◽  
Kinetics Of ◽  
Low Rate

ABSTRACT The toxicity of nucleoside analogs used for the treatment of human immunodeficiency virus infection is due primarily to the inhibition of replication of the mitochondrial genome by the human mitochondrial DNA polymerase (Pol γ). The severity of clinically observed toxicity correlates with the kinetics of incorporation versus excision of each analog as quantified by a toxicity index, spanning over six orders of magnitude. Here we show that the rate of excision of dideoxycytidine (zalcitabine; ddC) was reduced fourfold (giving a half-life of ∼2.4 h) by the addition of a physiological concentration of deoxynucleoside triphosphates (dNTPs) due to the formation of a tight ternary enzyme-DNA-dNTP complex at the polymerase site. In addition, we provide a more accurate measurement of the rate of excision and show that the low rate of removal of ddCMP results from both the unfavorable transfer of the primer strand from the polymerase to the exonuclease site and the inefficient binding and/or hydrolysis at the exonuclease site. The analogs ddC, stavudine, and ddATP (a metabolite of didanosine) each bind more tightly at the polymerase site during incorporation than normal nucleotides, and this tight binding contributes to slower excision by the proofreading exonuclease, leading to increased toxicity toward mitochondrial DNA.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

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