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DNA Damage and Genotoxicity

Dr. Lai

Garaj-Vrhovac et al [1992] exposed human whole-blood samples to continuous-wave 7.7
GHz radiation at power density of 0.5, 10 and 30 mW/cm2 for 10, 30 and 60 min. In
all experimental conditions, the frequencies of all types of chromosomal aberrations
(dicentric and ring chromosomes) and micronucleus were significantly higher than in
the control samples.
Garaj-Vrhovac et al. [1999] investigated peripheral blood lymphocytes of 12 subjects
occupationally exposed to microwave radiation. Results showed an increase in
frequency of micronuclei as well as disturbances in the distribution of cells over the
first, second and third mitotic division in exposed subjects compared to controls.
Haider et al. [1994] exposed plant cuttings bearing young flower buds for 30 h on both
sides of a slewable curtain antenna (300/500 kW, 40-170 V/m) and 15 m (90 V/m)
and 30 m (70 V/m) distant from a vertical cage antenna (100 kW) as well as at the
neighbors living near the broadcasting station (200 m, 1-3 V/m). Laboratory controls
were maintained for comparison. Higher micronucleus frequencies than in laboratory
controls were found for all exposure sites in the immediate vicinity of the antennae,
Tice et al. [2002] measured micronucleus frequency in human leukocytes using the comet
assay after exposure to various forms of cell phone signals. Cells were exposed at 37±1°C,
for 3 or 24 h at average specific absorption rates (SARs) of 1.0-10.0 W/kg. Exposure for 3
h did not induce a significant increase in micronucleated lymphocytes. However, exposure
to each of the signals for 24 h at an average SAR of 5.0 or 10.0 W/kg resulted in a
significant and reproducible increase in the frequency of micronucleated lymphocytes.
The magnitude of the response (approximately four fold) was independent of the
technology, the presence or absence of voice modulation, and the frequency.
Trosic et al. [2001] investigated the effect of a 2450-MHz microwave irradiation on
alveolar macrophage kinetics and formation of multinucleated giant cells after whole
body irradiation of rats at 5-15 mW/cm2. A group of experimental animals was
divided in four subgroups that received 2, 8, 13 and 22 irradiation treatments of two
hours each. The animals were killed on experimental days 1, 8, 16, and 30.
Multinucleated cells were significantly increased in treated animals. The increase in
number of nuclei per cell was time- and dose-dependent. Macrophages with two
nucleoli were more common in animals treated twice or eight times. Polynucleation
was frequently observed after 13 or 22 treatments.
Trosic et al. [2002] exposed adult male Wistar for 2 h a day, 7 days a week for up to 30
days to continuous 2450-MHz microwaves at a power density of 5-10mW/cm2.
Frequency of micronuclei in polychromatic erythrocytes showed a significant
increase in the exposed animals after 2, 8 and 15 days of exposure compared to shamexposed control.
Trosic et al. [2004] investigated micronucleus frequency in bone marrow red cells of rats
exposed to a 2450-MHz continuous–wave microwaves for 2 h daily, 7 days a week, at
a power density of 5-10 mW/cm2 (whole body SAR 1.25 +/- 0.36 (SE) W/kg). The
frequency of micronucleated polychromatic erythrocytes was significantly increased
on experimental day 15.
Trosic et al. [2006] exposed rats 2 h/day, 7 days/week to 2450-MHz microwaves at a
whole-body SAR of 1.25 +/- 0.36W/kg. Control animals were included in the study.
Bone marrow micronucleus frequency was increased on experimental day 15, and