The research on depleted uranium comes out of French researchers that
examined the manner DNA is affected by enriched and depleted uranium. The metal
or chemical effect it seems is the more important in depleted uranium
exposure.
Questions remain on the problem of inhalation and ingestion of depleted
uranium in the sands of Saudi/Iraq that has a high silica content and the health
effects that would be seen. Questions also remain on syngestic health effects
when you add in other toxic exposures experienced by Gulf War Veterans.
It is time for very focused research on these questions that should be led by
the veterans that can speak to the exposures. Their questions need to be
answered sooner rather than later, since it has been 19 years. The veterans
want help with their health conditions and treatment now. Their pain is real
physiological damage. What has happened to their organs and their blood?
What diagnosed illness are showing up and what are the hard numbers for each
diagnosed illness in gulf war veterans? It seems that information should be
just as important as the undiagnosed situation. The veterans and their families
want that type of information and that is why they have asked for registries of
each diagnosed illness, that would allow all veterans, even if they do not go to
the VA, to enter their medical information.
The veterans want a listing of deaths, cause of deaths, age of death, and
units that individuals were assigned during the Gulf War. These are not
unreasonable requests.
These requests and the information gleamed from such registries would also
assist medical professionals and researchers in answering these veterans
concerns.
Below is the article on depleted uranium written by Paul Eubrig, DVM and
below that is the scientific abstract of the actual research.
Depleted and enriched uranium affect DNA in
different ways.
Mar 16, 2010
Synopsis by Paul Eubig, DVM
Radiation is not uranium’s only health concern, say researchers who report
the less radioactive form of the metal can also damage DNA, but in a different
way that could also lead to cancer.
Meticulous research identifies for the first time how two main types of
uranium – enriched and depleted – damage a cell’s DNA by different methods. The manner – either by radiation or by
its chemical properties as a metal – depends upon whether the uranium is
processed or depleted.
This study shows that both types of
uranium may carry a health risk because they both affect DNA in ways that can
lead to cancer.
Why does it matter? Regulatory agencies determine safe uranium exposure based
on the metal’s radioactive effects. Currently, safe exposure levels for workers
and military personnel are based on enriched uranium – which is the more
radioactive form and is considered to have a higher cancer risk than depleted
uranium. Uranium exposure has been shown to affect bone, kidney, liver, brain,
lung, intestine and the reproductive system.
Yet, many people are exposed at work or through military activities to the
less radioactive, depleted form. They
may not be adequately protected based on current methods that evaluate uranium’s
health risks.
As a naturally-occurring element, most people are exposed to low levels of
uranium through food, air and water. Additional exposure to uranium occurs when
it is mined and altered for civilian or military purposes. Workers who process
uranium into nuclear fuel for energy or weapons face additional exposure to
enriched uranium. Depleted uranium – a
by-product of the enriching process – is used in military armor and in
armor-piercing ammunition. Soldiers on a battlefield or civilians who live near
these areas can be exposed to this form.
Studying uranium’s effects is challenging because it can damage DNA in two
distinct ways. The similarities make it difficult to tease apart which form and
which method is responsible for the harm.
The French scientists who conducted this study started by exposing mouse cell
cultures to enriched and depleted uranium. They applied different toxicity tests
to distinguish which uranium caused which kinds of DNA damage.
They found the enriched uranium caused breaks in the chromosomes that make up
the DNA. Called clastogenic damage, the effects were related to the amount of
radiation the enriched uranium released.
In addition, the radiation-related effects were more pronounced, suggesting
that the chromosome breaks were caused by the radiation and not by the chemical
effects of uranium. The chemical effects of uranium did not seem to contribute
to the DNA damage seen with enriched uranium, at least in the context of this
study.
However, the depleted uranium had a
different type of effect. It altered the number of chromosomes in the cell.
These effects are due to improper migration of chromosomes when cells divide.
This type of damage – called aneugenic damage – was not related to the amount of
radiation the cells received and was likely caused by the metal properties of
uranium.
The methods used in this study clearly provide a new way to assess the
different types of genetic harm caused by uranium. The findings will help ferret out whether the
genetic damage caused by the depleted uranium also carries a high risk of
causing cancer, which is something those who work with or are around the metal
want to know. Further study is warranted to truly assess human health
risks.
Toxicology Letters
Volume 192, Issue 3, 15 February 2010,
Pages 337-348
——————————————————————————–
Copyright © 2009 Elsevier
Ireland Ltd All rights reserved. Cited By in Scopus (0)
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Different genotoxic profiles between depleted and enriched uranium
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C. Darollesa, D. Broggiob, A. Feugiera, S. Frelona, I. Dublineauc, M. De Meod
and F. Petitota, ,
a Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire de
Radiotoxicologie Expérimentale IRSN/DRPH/SRBE/LRTOX, Site du Tricastin – B.P.
166, 26702 Pierrelatte Cedex, France
b Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire
d’Évaluation de la Dose Interne IRSN/DRPH/SDI/LEDI, BP-17 92262
Fontenay-aux-Roses, France
c Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire de
Radiotoxicologie Expérimentale IRSN/DRPH/SRBE/LRTOX, BP-17 92262
Fontenay-aux-Roses, France
d Laboratoire de Biogénotoxicologie et Mutagenèse Environnementale (EA 1784),
Faculté de Médecine et Pharmacie, Université de la Méditerranée, 27 Bd Jean
Moulin, Marseille Cedex 05, France
Received 13 August 2009; revised 3 November 2009; accepted 4 November 2009.
Available online 13 November 2009.
Abstract
Uranium is an alpha-particle-emitting heavy metal. Its
genotoxicity results from both its chemical and its radiological properties that
vary with its isotopic composition (12% enriched uranium in 235U (EU) has a
specific activity 20 times higher than 0.3% depleted uranium in 235U (DU)). The
influence of the isotopic composition of uranium on its genotoxic profile
(clastogenic/aneugenic) has never been described. The present study evaluated
genotoxic profile of uranium with the cytokinesis-block micronucleus centromere
assay. C3H10T1/2 mouse embryo fibroblasts were contaminated with either DU or EU
at different concentrations (5 μM, 50 μM and 500 μM). Cells received low doses
ranging from 0.3 μGy to 760.5 μGy. The frequency of binucleated cells with one
micronucleus increased with increasing concentrations of both DU and EU in the
same way. EU induced more centromere-negative micronuclei and nucleoplasmic
bridges than DU. A correlation between these two clastogenic markers and
ionizing radiation doses was observed. Finally, this study showed that the
genotoxic profile of uranium depends on its isotopic composition. DU and EU are
low and high clastogens, respectively. However, DU aneugenic effects remain
high. Thus, there is a need to study the potential role of aneugenic effects of
DU in carcinogenic risk assessment linked to uranium internal exposure.
Keywords: Depleted uranium; Enriched uranium; Micronucleus; FISH; Aneugen;
Clastogen
Abbreviations: MN, micronucleus; BN-1MN, binucleated cell with one
micronucleus; BN-1MNC+, binucleated cell with one centromere-positive
micronucleus; BN-1MNC−, binucleated cell with one centromere-negative
micronucleus; Mono-MNx, mononucleated cells with micronuclei; BN-NPB,
binucleated cell with nucleoplasmic bridge
Article Outline
1. Introduction
2. Materials and methods
2.1. Cell
culture and U preparation
2.2. Cell treatment
2.3. Cell death
assessment
2.3.1. Cytotoxicity test
2.3.2. Sub G0–G1 cell population
assessment
2.4. Uranium measurement
2.5. Cytokinesis-block micronucleus
assay
2.6. Fluorescence in situ hybridization (FISH) with a pancentromeric
DNA probe
2.7. Slide scoring
2.7.1. Cytokinesis-block micronucleus
assay
2.7.2. Fluorescence in situ hybridization (FISH) with a pancentromeric
DNA probe
2.8. Monte Carlo dose calculation
2.9. Statistical
analysis
3. Results
3.1. Cell death and cell proliferation
assessment
3.2. Cytokinesis-block micronucleus (CBMN) assay and Fluorescence
in situ hybridization (FISH) with a pancentromeric DNA probe
3.2.1.
Binucleated cells with one micronucleus (BN-1MN)
3.2.2. Fluorescence in situ
hybridization (FISH) with a pancentromeric DNA probe
3.2.3. Mononucleated
cells with micronuclei (Mono-MNx)
3.2.4. Nucleoplasmic bridges in binucleated
cells (BN-NPBs)
3.3. Uranium content of cells
3.4. Estimated doses
received by cells
3.5. Correlation of dose received by cells with the
observed biological effects
4. Discussion
4.1. MN induction in binucleated
cells
4.2. CBMN centromere assay
4.3. MN in mononucleated cells and NPB in
binucleated cells are markers of aneugenic and clastogenic actions of uranium,
respectively
5. Conclusion and prospects
Conflict of interest
statement
Acknowledgements
References
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