Environmental and Molecular Mutagenesis - Legacy Tobacco ...

224 1989 EMS Abstracts - f
http://legacy.library.ucsf.edu/tid/clb93d00/pdf
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Notes exon 9 on1y . UYtraolet-light-induced mutants produced predominantly
wild-type amplific ion patterns (10/14), and X-ray induced mostly
deletion patterns .15) in either exon 9 or exon 3 . These observations
are consistent with previous data from Southern analyses . Deletions
occur most frequently at the 3'end of the gene, suggesting the possible
existence of hot spot(s) for deletions in this region . Supported in part
by Laboratories for Genetic Services (LGS) and an EPA Distinguished
visiting Scientists Award to AWH .
COMPARATIVE STUDIES ON SEVERAL INDICES OF NUCLEAR DAMAGE IN HUMAN
PERIPHERAL LYMPHOCYTES . K .X . Xue, S . Wang, P . Zhuo, G .J .Ma, Cancer Institute
of Jiangsu Province, Nanjing ( China )
In order to use approperiately NAT and explore possibility of use of the test in
human cells, authers used Y-rays as mutagenic and carcinogenic irradiated whole blood
in vitro, prepared directly smears of isolated lymphocytes, studied comparatively
dose-response relationship of 4 types of nuclear damage . main results of the study
are given as follows :
1 . In doses from 0 to 3 Grays MNF ( freqency of micronucleus ), INF ( freqency of
Irregular nucleus), KNF (frequency of karyorrhetic nucleus), anC PNF ( frequency of
pyknotic nucleus) increase along with increase of irradiated doses . At 5 grays INF
still increases, but MNF,KNF and PNF decrease .
2 . In doses from 0 to 3 grays regression equation of 4 indices of nuclear damage
are as follows ( D means dose,r means correlative coefficient) :
MNF : Y-0 .3433+0 .1052D,r-0 .9128,p 0 .05 ; INF : Y-7 .2178+2 .1817D,r-0 .8846,p 0 .05 ;
KNF : Y-0 .6462+0 .2014D,r-0 .7286,p 0 .05 ; PNF : Y=0 .2774+0 .0728C,r-0 .5484,p 0 .05 .
Finally according to synthetical analysis of correlative coefficient, intercept,
regression coefficient and feasibility of indices of nuclear damage,we could
consider it suitable that nuclear anomalies in human peripheral lymphocytes include
I' .'ir,INF and KNF .
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SISTER CHROMATID EXCHANGES INDUCED IN PERIPHERAL LYMPHOCYTES OF F10RXERS EXPOSED TO LOW
CONCENTRATIONS OF STYRENE . J .W . Yager, S .M . Rappaport, and W .M . Paradisin, University
of California, Berkeley, CA (USA)
Following inhalation, styrene is absorbed and metabolized to styrene-7,8-oxide (SO)
which is mutagenic in in vitro test systems ; SO also induces sister chromatid exchanges
(SCEs) and chromosomal aberrations in human lymphocytes in vitro . However,
previous occupational studies have not shown increases in lymphocyte SCES of workers
exposed to styrene at 8-hour time weighted average (TWA) concentrations below about
40-50 ppm . In this study, relevant exposure data and biological measures were obtained
longitudinally during one year at a boat manufacturing facility that utilizes styrene
as a solvent in preparation of reinforced plastics materials . 8KC Model 530 solid
sorbent diffusion badges were used to measure full-shift breathing zone styrene concentrations
up to 7 times over the year on the same 46 individual workers . Styrene in
exhaled air was also determined up to 3 times per day . Blood was obtained for SCE
analyses ; 80 cells were scored per sample . Health and occupational histories were obtained
. Mean TWA exposure was 64 .2 m/N3 t 71 .5 (or 15 .1 ppm * 16 .8) styrene in air .
Overall mean SCE was 6 .41 t 0 .96 per cell (rangee 4 .73 - 9 .47) . Smokers comprised
54% of the population and smoked an average of 9 .1 cigarettes per day . Statistical
analysis utilizing a bivariate linear regression model indicates that both smoking and
exposure to styrene contribute significantly to an increase in SCEs (P < 0 .000011 A~
0 .62) . Most strikingly, it can also be shown that these two factors contribute to the
increase in SCEs relatively free of the influence of one another . Results indicate
that SCEs may be induced at rather lower styrene exposure concentrations than have
previously been reported .
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THE ROLE OF GAP JUNCTIONAL INTERCELLULAR COMMUNICATION DURING MULTISTAGE CARCINOGENESIS
Hiroshi Yamasaki, International Agency for Research on Cancer, 150 cours Albert Thomas,
69372 Lyon cedex 08, France .
An important role of gap junctional intercellular communication is to maintain
homeostasis of cells within a given tissue . Since carcinogenesis involves the breakdown
of homeostasis in the tissue, it is conceivable that altered gap junctional
intercellular communication is involved in the multistage carcinogenesia process . A
possible role of blocked intercellular communication during tumor promotion is strongly
supported by the fact that various tumor promoting agents inhibit gap junctional communication
in cultured cells . We have recently extended this finding to in-vivo ; the
administration of liver-specific tumor promoter phenobarbital reduced theeveT of gap
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