𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Levels of DNA strand breaks and superoxide in phorbol ester-treated human granulocytes

✍ Scribed by H. Chaim Birnboim; Jagdeep K. Sandhu

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
126 KB
Volume
66
Category
Article
ISSN
0730-2312

No coin nor oath required. For personal study only.

✦ Synopsis

Phorbol ester treatment of granulocytes triggers release of superoxide (O 2 2 . ) and a concomitant burst of DNA strand breaks. The relationship between the amount of O 2 2 . and the number of DNA breaks has not previously been explored. To quantify the relatively large amount of O 2 2 . generated over a 40-min period by 1 3 10 6 granulocytes/mL, a discontinuous ''10-min pulse'' method employing cytochrome c was used; 140 nmol O 2 2 . per 1 3 10 6 cells was detected. DNA strand breaks were quantified by fluorimetric analysis of DNA unwinding (FADU). To vary the level of O 2 2 . released by cells, inhibitors of the respiratory burst were used. Sodium fluoride (1-10 mM) and staurosporine (2-10 nM) both inhibited O 2 2 . production. In both cases, however, inhibition of strand breakage was considerably more pronounced than inhibition of O 2 2 . . Zinc chloride (50-200 µM) inhibited both O 2 2 . and DNA breaks, approximately equally. Dinophysistoxin-1 (okadaic acid) inhibited O 2 2 . production more effectively than it inhibited DNA breaks. O 2 2 . dismutes to H 2 O 2 , a reactive oxygen species known to cause DNA breaks. The addition of catalase to remove extracellular H 2 O 2 had no effect on DNA breakage. Using pulse field gel electrophoresis, few double-stranded breaks were detected compared to the number detected by FADU, indicating that about 95% of breaks were single-stranded. The level of DNA breaks is not directly related to the amount of extracellular O 2 2 . or H 2 O 2 in PMA-stimulated granulocytes. We conclude that either an intracellular pool of these reactive oxygen species is involved in breakage or that the metabolic inhibitors are affecting a novel strand break pathway.

📜 SIMILAR VOLUMES

Induction of DNA strand breaks by ethyle
Induction of DNA strand breaks by ethylene oxide in human diploid fibroblasts
✍ Jonas Nygren; Björn Cedervall; Stefan Eriksson; Mária Duškinská; Ada Kolman 📂 Article 📅 1994 🏛 John Wiley and Sons 🌐 English ⚖ 613 KB

In vitro exposure of normal human diploid fibroblasts (strain VH-10) to ethylene oxide (EtO) induced DNA strand breaks in the dose range of 2.5-30 mMh of EtO. Alkaline DNA unwinding (ADU), neutral filter elution (NFE), pulsed field gel electrophoresis (PFGE), and the comet assay were used to measure

Rejoining of DNA strand breaks induced b
Rejoining of DNA strand breaks induced by propylene oxide and epichlorohydrin in human diploid fibroblasts
✍ Miroslav Chovanec; Maria Näslund; Irina Spivak; Maria Dušinská; Björn Cedervall; 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 153 KB

The repair kinetics of DNA single-and double-PO, respectively, were rejoined within 4 hr after the strand breaks (SSBs, DSBs) induced with two carcin-treatment (a half-life of Ç2.5 hr), with little further ogenic epoxides, propylene oxide (PO) and epichl-repair thereafter. At lower dose of ECH (1 mM

Rejoining of DNA double-strand breaks in
Rejoining of DNA double-strand breaks in human fibroblasts and its impairment in one ataxia telangiectasia and two fanconi strains
✍ Coquerelle, Thérèse M. ;Weibezahn, Karl F. 📂 Article 📅 1981 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 376 KB

## Abstract Using the technique of neutral elution through polycarbonate filters as a measure of DNA length, and hence of the number of double‐strand breaks incurred as a result of radiation damage, we found that normal human fibroblasts rejoin 50% of all breaks within only 3 min (37°C). This fast

Joining of correct and incorrect DNA dou
Joining of correct and incorrect DNA double-strand break ends in normal human and ataxia telangiectasia fibroblasts
✍ Markus Löbrich; Martin Kühne; Jana Wetzel; Kai Rothkamm 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 175 KB 👁 2 views

Chromosomal aberrations are believed to result from the incorrect joining of DNA double-strand breaks (DSBs). In an attempt to investigate induction and rejoining quality of DSBs following ionizing radiation exposure in specific genomic locations of mammalian DNA, an experimental approach based on S

Lack of detectable defect in DNA double-
Lack of detectable defect in DNA double-strand break repair and DNA-dependent protein kinase activity in radiosensitive human severe combined immunodeficiency fibroblasts
✍ Nathalie Nicolas; Nicholas J. Finnie; Marina Cavazzana-Calvo; Dora Papadopoulo; 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 English ⚖ 503 KB

The initial step of the V(D)J recombination occurs through the generation of a DNA double-strand break (dsb). Defects in the DNA-dependent protein kinase complex (DNA-PK) result in an inability to perform either V(D)J recombination or any dsb repair effectively. The human autosomal T-B-severe combin