Handbook of Solvents - George Wypych - ChemTech - Ventech!

1376 Nachman Brautbar
ation in cytogenic changes between subjects suggested varying degrees of exposure to
mutagenic agents. Brandt et al. 13 studied the effects of exposure to organic solvents and
chromosomal aberrations. Ten patients had a history of daily handling of organic solvents
for at least one year preceding the diagnoses of non-Hodgkin�s lymphoma. All have been
exposed to a variety of solvents to include aromatic and aliphatic compounds. Forty-four
patients for only a shorter period of time worked with organic solvents, and therefore served
as the control group. There was a statistically significant increase in chromosomal changes
in the exposed group compared to the non-exposed group. The authors suggested based on
their results, that at diagnosis of non-Hodgkin�s lymphoma, patients with a history of significant
occupational exposure to organic solvents tends to have a larger number of chromosomal
aberrations in the lymphoma cells. Furthermore, certain aberrations may be
characteristic for the exposed patients. They have concluded that the over representation of
certain chromosome aberrations in non-Hodgkin's lymphoma patients occupationally exposed
to organic solvents supports the concept that these exposure may be relevant for the
subsequent development of non-Hodgkin's lymphoma. Their data are in agreement with the
studies published previously, indicating that workers handling organic solvents and other
petroleum products have an increased frequency of chromosomal aberrations in lymphocytes.
12,14,15,16 Indeed, association between exposure to solvents and other chromosomal
changes in the cells have been studied by other investigators, describing chromosomal
changes in acute non-lymphocytic leukemia. 3,17,18,19 In cultured cells, Koizumi 20 examined
the effects of benzene on DNA syntheses in chromosomes of cultured human lymphocytes.
They have shown an increased incidents of chromatoid gaps and breaks in cultures treated
with benzene, compared to those who were untreated with benzene. They also showed
changes in DNA metabolism in the form of inhibition of syntheses in those samples which
were treated with benzene. This observation was confirmed by other investigators 21 who
have shown an increased chromosomal aberrations in cultured human leukocytes exposed
to benzene. From the in vitro to the in vivo experimental animals, it was shown that treated
rats with benzene, were found to have increased chromosomal changes taken from the bone
marrow as compared to the non-treated animals. 22 It was of interest that the degree of chromosomal
changes that were induced by benzene, were similar to that induced by toluene 23
(probably secondary to the benzene in toluene). Experimental rabbits treated with benzene
also showed a significant amount of bone marrow chromosomal changes persisting up to 60
days after the end dosing with benzene. 24
A patient who has developed aplastic anemia after exposure to benzene, was shown to
have significant chromatoid fragments. 25 A cytogenic study which was carried out later, 26
on a patient who developed leukemia after 22 years of continuous exposure to a high concentration
of benzene, showed that later in the process there were changes in 47 chromosomes
in the bone marrow. Sellyei et al. 27 studied patients who developed pancytopenia
after having been exposed for 18 months to benzene. Significant chromosomal changes
were detected even 7 years after remission from the anemia and the presentation of leukemia.
In line with these changes, Forni et al. 28 have studied 25 subjects with a history of
hematopoietic abnormalities and benzene exposure, and compared these to 25 matched controls.
They have shown that 18 years after clinical and hematological symptoms chromosomal
aberrations were increased as compared to the control group. In 1965, Tough et al. 29
have studied chromosomes of workers exposed to benzene for periods varying from 1 to 18
years. They have also shown a small but significant increase in chromosomal changes com-