[abstract] HBO AND DNA DAMAGE - NEW INSIGHTS INTO WHETHER HBO MAY PROMOTE CANCER.

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[abstract] HBO AND DNA DAMAGE - NEW INSIGHTS INTO WHETHER HBO MAY PROMOTE CANCER.

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Title: [abstract] HBO AND DNA DAMAGE - NEW INSIGHTS INTO WHETHER HBO MAY PROMOTE CANCER.
Author: Rothfuss, A; Radermacher, P; Speit, G
Abstract: BACKGROUND: Meta-analyzes of the literature did not find argument in favour of a cancer-promoting effect (1, 2), but the question remains whether HBO-induced O2 free radicals may cause oxidative stress-induced mutagenicity and cancer formation. METHODS: HBO-induced DNA damage (alkaline comet assay) as well as chromosome (micronucleus test) and gene mutations (HPRT test) were assessed both in vivo in healthy volunteers and in vitro in human whole blood, isolated lymphocytes and hamster V79 cells. Antioxidant activity, nitric oxide production and HSP 70 expression were measured to characterize the pathophysiologic mechansims as well as putative adaptive responses. RESULTS: Both in vitro and in vivo HBO caused DNA damage depending on exposure time and pressure (3, 4), while mutagenicity was less pronounced. DNA lesions were only present in vivo after an initial HBO exposure and had disappeared 24 h later (4). A stepwise increase of the HBO exposure prevented DNA damage in vivo (4). HBO changed neither Vitamine A, C, E, nitrate/nitrite and glutathione levels nor catalase, superoxide dismutase or glutathione peroxidase activity (5), supplementation with Vitamine E or N-Acetylcysteine did not modify the amount ofDNA lesions (5). CONCLUSIONS: HBO causes dose-dependent DNA breaks, but under clinical conditions repair and adaptive mechanisms prevent a mutagenic effect (6, 7). A cancer promoting effect resulting from DNA damage cannot, hence, be assumed. In healthy volunteers neither exogenous antioxidant supply nor endogenous capacity assumes any importance for this ad'aptive response. Other mechanisms such as induction of stress-inducible proteins have to be taken into account. REFERENCES: 1. Feldmeier et al, Undersea Hyperb Med 1994;21:467; 2. Almeling et al, Strahlenther Onkol 1996;172 Suppl II:30; 3. RothfuB et al, Environ Mol Mutagen 1999;34:291; 4. Dennog et al, Mutagenesis 1996;11 :605; 5. Dennog et al, Mutat Res 1999;428:83; 6. Speit et al, Mutagenesis 1998;13:85; 7. RothfuB et al, Carcinogensis 1998;19:1913.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/6688
Date: 2000

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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