Environmental and Molecular Mutagenesis - Legacy Tobacco ...

ultraviolet irradiation o'f DT resistance in cultures of the transformed,
xeroderma pigmentosum complementation group-A cell line XP20S(SV40), and of
the Chinese hamster ovary ~CHO) repair-defective mutant 43-3B . In both
cultures, there was a do~e-dependent increase in the frequency of toxinresistant
cells . On an equal-dose basis, higher frequencies were observed in
the repair-deficient cell lines than in their respective repair-proficient
controls, GM637(SV40) and CHO-9 . At equal levels of survival, however, the
frequencies of DTs cells were similar in the repair- defi~ient and proficient
cells . These result provide further evidence that the DT" cells detected by
the autoradiographic assay are indeed mutants . They also indicate a simple
method of studying various aspects of mutation in cells that, because of e .g .
defective DNA-repair, are hard to clone and use in a colony assay . (Work
supported by the Israel Cancer Association .)
583
SOFTWARE DEVELOPMENT FOR MICRONUCLEUS (MN) SCORING . R .R . Tice, J .T . MacGre9or*, C .
Campfield, A . Pellom, L . Williams** and C .H . Nauman**, Integrated Laboratory Systems,
PO Box 13501, Res . Tri . Park, NC 27709, *Toxicology Consulting Services . Inc ., 383
Diablo Rd, Suite 100, Danville, CA 94526, and **EPA/EMSL, P0 Box 89193, Las Vegas, NV
89193 .
Based on input from a panel of experts in the field, a software program, suitable
for an IBM compatible PC, has been developed for the collection and analysis of
micronuclei data obtained from in vtvo test systems . Experimental design information
and MN data obtained on a number of cell types are easily entered using a series of
menus, statistically analyzed by a variety of statistical models and presented both
in tabular and graphic form . In the statistical analysis, the data are evaluated for
scorer, sex, treatment, sample time, and animal effects . The use of this software
will help to standardize in vivo MN data analysis and presentation . Although the
research described in this article has been supported by the U .S . EPA through
contract number 68-C8-0068 to Integrated Laboratory Systems, it has not been
subjected to Agency review and therefore does not necessarily reflect the views of
the Agency and no official endorsement should be inferred .
.
584 •
ANALYSIS OF MOUSE MICRONUCLEI BY HIGH SPEED FLOW CYTOMETRY .
A. M . Tometsko, Litron Laboratories, Rochester, N. Y . (USA)
The mouse micronucleus assay is widely used to evaluate the clastogenic activity of
chemicals . The essay involves scoring the number of cells containing micronuclei (MNS) In
either blood or bone marrow preparations using fluorescent or bright field microscopy . The
conventional assay is labor intensive end tedlus, and requires many hours of microscopic
examination to complete an assay. High speed flow cytometry provides the means for
analyzing fluorescent cells as they pass through a laser beam at 2,000 cell per second and
permits the analysis of 30-50 times more cells then manual screening tn e shorter time. For
FCM analysis, the cells are stained with fluorescent dyes which effectively label cellular
nucleic acids (e .g. MNs) . Experiments will be presented which highlight the distribution of
micronucleated cells in peripheral blood of normal and ctasto0en treated mice. The location of
MNs in different blood cell populations will be shown and will provide en indicetion of the
feasibility of developing an automated FCM based analysis protocol• The distribution of MNcells
will be presented using histograms and bivariate graphs. Correlations will be made
between manual scoring and analysis by high speed flow cytometry .
585
COMPARISON OF IN VIVO SOMATIC CELL MUTATION, CHROlie/SOME ABERRATION, SISTER CHROMATID
EXCHANGE, MICRONUCLEI FORMATION AND URINE MUTAGENICITY IN STEEL FOUNDRY WORKERS . D .J .
Tomkins, D .R . McCalla, and E .S . Gibson, McMaster University and Dofasco Inc .,Hamilton,
Ontario, Canada .
Preliminary results of genetic toxicologic monitoring of 125 steel foundry workers
with a higher rate of lung cancer have been reported (Environ . Mutag . 7(S .3) : 33,1985) .
Chromosome aberration (CA), sister chromatid exchange (SCE), and morning and afternoon
urine mutagenicity (MUTAM,MUTPM), but not micronuclei (HN), were all significantly
elevated with smoking (p- .001, .004, .008, .005 respectively), but not with occupation .
The somatic cell mutation test (SCMT) has now been completed for 37 workers and the
statistical analysis did not show any significant effects of smoking or occupation .
In the case of CA, there was a significant interaction between smoking and occupation,
particularly when gaps were not included in the total number of aberrations per cell
(p- .01) . When specific types of abnormalities were analyzed separately, breaks
appeared to be the moat important contributors to the effect of the interaction . Two
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
1989 EMS Abstracts 201
Notes