Environmental and Molecular Mutagenesis - Legacy Tobacco ...

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DETECTION OP MICRONUCLSI IN PERIPHERAL BLOOD LYMPHOCYTES OF PATIENTS WITH ESOPHAGEAL
CANCER AND IMPROVEMENT OF THE METHOD . 2 . Qingfan, F . Shuli, and Y . Bin . Dept . of
Pathology, Henan Medicaltniversity, 2hengzhou, Henan, P .R . China .
Thirty-four cases of esophageal cancer were chosen for this study . Their age ranges
from 30 to 75 . The diagnosis of the patients were confirmed by cytological examination
in our department . They had not received radiotherapy, chemotherapy or other
immunosuppressive agents recently . Thirty-four healthy persons were taken as the control .
The method consists of taking 2 to 3 drops of blood from the ear lobe of the examined
person, treating the blood sample with Tris-ammonium chloride buffer solution to hemolyze
the red cells and then using the simplifled cytocentrifuge developed by the author to
prepare the smears, the white cells can be concentrated and spread monolayerly onto a
small area of the microscope slide, and the morphological details of the cells can be well
preserved .' The background of the smear is clear, which facilitates scoring the
micronuclei in lymphocytes . The normal range of micronuclei in lymphocytes in our study
was 0-3 0/00 . It shows that the results of our improved method are similar to those with
the ordinary method in which blood was taken by venous puncture . The improved method is
not only fast and reliable, but liable to be accepted by the persona examined . The mean
frequency of the micronuclei in the peripheral blood lymphocytes of the patients with
esophageal cancer was 2 .8 0/00 as compared with 0 .832 0/00 in the control . The difference
is statistically significant (p < 0 .001), but there is no marked specificity for the
diagnosis of esophageal cancer, because the frequency in half of the patients with
esophageal cancer is below 2 0/00, which superimposes with the control .
461 The SOS Chromotest : an analysLs from published data on 430 chemio3ls.
P . Quillardet, E. Touati and M. Hofnung . Institut Pasteur, UPMTG - CNRS UA271 - INSERM
U 163 - Paris France .
We have made use of an E. coli strain carrying a fusion of gene lacZ to gene 4fu1, one of the
SOS gene, to devise a rapid assay for genotoxins : the SOS Chromotest (Quillardet et al ., Proc. Natl .
Acad. Sci ., 79 : 5971, 1982 ; Mutation Res . 147: 65, 1985). The assay is performed in few hours and
involves simple enzymatic assays . It allows to classify compounds according to their SOS inducing
potency (SOSIP), defined as their ability to induce the expression af the sfGl : aacZ fusion. To day,
works from a number of laboratories using the SOS Chromotest have been published . We have
reviewed data obtained with the SOS Chromotest on 430 chemicals issued from 40 publications arising
from 20 different laboratories . This led us to evaluate further the potential of the SOS Chromotest to
detect carcinogens and to compare its response to that of the Salmonella / microsome assay . The results
confirm that in addition to its remarkable simplicity, the SOS Chromotest is a powerful method to
detect and evaluate genotoxic agents
462
COOPERATIVE EFFECTS IN ASSAYS OF CHEMICAL MIXTURES OF ATMOSPHERIC POLLUTANTS .
A .S . Raj and D .M . Logan . York University, North York, Ontario, Canada M3J 1P3
Exposure to pollutants in natural atmospheres usually involves complex mixtures
of chemicals rather than a single pollutant . In such cases risk assessment is
difficult if not impossible because the chemicals may interact in several
unpredictable ways . The object of this research is to measure chemical interactions
in certain bioassaya and define quantitatively their cooperativity . Nine common
atmospheric pollutants (4 promutagens, 1 direct acting mutagen and 4 non mutagens)
have been tested alone and in combinations of two and three in the Ames and micronucleus
assays . For each of the combinations a strictly additive dose response has
been calculated and compared with the actual response . In the Ames assay most
mixtures produce fewer revertants than predicted and this is not due to S9
limitation . In cases where the predicted response is biphasic ag . BaP and DMBA due
to different threshold dosages, the actual response is not biphasic but parallels
that of the lower threshold chemical . In a few mixtures (three or more chemicals)
inclusion of the direct acting mutagen 1-nitropyrene produces a highly synergietic
response ie . more than 5 times the additive response . Weighting factors have been
calculated for each chemical tested which can be used to predict the response of
new mixtures of the chemicals . This approach should prove valuable in predicting
the risk due to environmental pollutants .
This research was supported by a grant from the Ontario Ministry of the Environment .
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
1989 EMS Abstracts 159
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