Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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methods, the authors demonstrated increased recruitment of
cells responsive to rGM–CSF following exposure to a variety
of agents with documented leukemogenic potential. These
findings support the possibility that transient alterations
in HPC differentiation may be an important factor in the
early stages of development of leukemia secondary to
chemical or drug exposure.
Source: Deutsche Shell Chemie GmbH Eschborn
06–JAN–1997 (566)
Type: other: Hematotoxicity
Remark: This research involved exposure of CBA/Ca male mice to
benzene vapor in varying concentrations. Exposure to 300
ppm 6 hrs/day, 5 days/week, for 16 weeks is highly
leukemogenic. Exposure for the same time to 100 ppm is
alsoleukemogenic. Concentrations from 25 ppm to 400 ppm 6
hrs/day, 5 days/week, for 10 exposures produce an
increasinglymphopenia. Exposure to 100 ppm for the same
exposure timeproduces anemia, decrease in stem cell content
of marrow, and marrow cellularity.
Source: Deutsche Shell Chemie GmbH Eschborn
06–JAN–1997 (258)
Type: other: Hematotoxicity
Remark: Effects of benzene inhalation on mouse pluripotent
hemapoietic stem cells were evaluated. Male mice 8–12 wk
old were exposed to 400 ppm benzene for 6 h/d, 5 d/wk, for
up to 9 1/2 wk. At various time intervals exposed and
control animals were killed, and cardiac blood was
evaluatedfor changes in white blood cell (WBC) and red blood
cell (RBC) content. In addition, femora and tibiae were
evaluated for total marrow cellularity, stem cell content
(as measured by the spleen colony technique), and the
percent of stem cells in DNA synthesis (as determined by
thetritiated thymidine cytocide technique). Exogenous
spleen colonies grown from marrow of exposed animals were
counted, identified, and scored by histological type.
Exposure to benzene caused sigificant depressions of RBCs
and WBCs throughout the exposure period, which continued for
at least14 d after exposure. Bone marrow cellularity and
stem cell content were also depressed in exposed animals
throughout the study. Tritiated thymidine cytocide of
spleen colony–forming cells was generally increased in
exposed animals, perhaps indicating a compensatory response
to the reduction of circulating cells. Spleen colonies of
all types were depressed after exposure to benzene.
Source: Deutsche Shell Chemie GmbH Eschborn
06–JAN–1997 (259)
Appendix D: Benzene SIDS Dossier
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