Chromosome aberrations levels

The LC50 in rats is 4.8 ppm. No increase in chromosomal aberration levels was seen in hamsters that inhaled ozone, although small increases in chromatid aberration levels were seen. Pregnant rats exposed to up to 1.97 ppm during parts or all of organogenesis had no defects in their offspring. 

Pampfer, S., Streffer, C., 1989. Increased chromosome aberration levels in cells from mouse fetuses after zygote X-irradiation. Int. J. Radiat. Biol. 55, 85-92. 

In a case-control study of pesticide factory workers in Brazil exposed to methyl parathion and formulating solvents, the incidence of chromosomal aberrations in lymphocytes was investigated (De Cassia Stocco et al. 1982). Though dichlorodiphenyltrichloroethane (DDT) was coformulated with methyl parathion, blood DDT levels in the methyl parathion-examined workers and "nonexposed" workers were not significantly different. These workers were presumably exposed to methyl parathion via both inhalation and dermal routes however, a dose level was not reported. The exposed workers showed blood cholinesterase depressions between 50 and 75%. However, the baseline blood cholinesterase levels in nonexposed workers were not reported. No increases in the percentage of lymphocytes with chromosome breaks were found in 15 of these workers who were exposed to methyl parathion from 1 week to up to 7 years as compared with controls. The controls consisted of 13 men who had not been occupationally exposed to any chemical and were of comparable age and socioeconomic level. This study is limited because of concomitant exposure to formulating solvents, the recent history of exposure for the workers was not reported, the selection of the control group was not described adequately, and the sample size was limited. 

Chromosome aberrations were detected in lymphocytes of individuals acutely intoxicated by methyl parathion by the inhalation route (Van Bao et al. 1974). Blood samples were taken 3-6 days after exposure and again at 30 and 380 days. A temporary but significant (p<0.05) increase was noted in the frequency of stable chromosomal aberrations in the exposed individuals. The study limitations include small sample size, absence of a control group, lack of quantification of exposure levels, and a possible concomitant exposure to other substances via the dermal route. 

Eleven male volunteers aged 20-30 years ingested lead acetate for 49 days. PbB levels were kept at approximately 40 pg/dL. The frequency of chromosome aberrations was assayed after lymphocyte culture for 72 hours and found to be no different from that of 10 controls. The lymphocytes from lead-exposed subjects did show a higher mitotic activity (Bulsma and DeFrance 1976). 

A survey of investigations on chromosome aberrations in peripheral blood lymphocytes of people exposed to elevated levels of radon in the atmosphere shows non linear dose relationship. At very low doses a sharp increase occured, followed by a plateau. A hypothesis involving DNA repair mechanism is given. 

The main problems of the study of chromosome aberrations, caused by radon and daughters at their most frequently existing dose levels, i. e. boardering the natural burdens, ares (i) to get statistical significance at very low doses, and (ii) to study their induction by internal exposure to alpha emitters only. 

In the following is shown that in vivo investigations on chromosome aberrations in people exposed to an elevated level of radon and daughters provide similar dose response. 

No calculation of the RBE of the alpha rays at this very low dose range can be made, as no in vitro study was carried out with x- or gamma rays at such low dose levels. The lowest dose of x-rays with which a chromosome aberration study has been carried out was 4 mGy (Pohl-Riiling et al.t 1983) A very rough estimation of the RBE at doses between 2 and 4 mGy yield a value between 2 and 3 ... 

Cao Shu-yuan, Deng Zhicheng, Shou Zhen-ying, Li Yun-hua, and Yu Cui-fang, Lymphocyte Chromosome Aberrations in Personnel occupationally Exposed to Low Levels of Radiation, Health Physics 41 586-587 (1981). 

Pohl-Ruling, J., P. Fischer, and E. Pohl, The Low-Level Shape of Dose Response for Chromosome Aberrations, in Proceedings of the International Symposium of Late Biological Effects of Ionizing Radiation (International Atomic Energy Agency) pp. 315-326, Vienna, Austria, (1978). 

Binder, R. Nowotny, W. Schmidt, N.0. Bianchi, P.P.W. van Buul, A.T. Natarajan, L. Fabry, A. Leonard, M. KucerovA, D.C. Lloyd, U. Mukherjee, G. Obe, F. Palitti, and T. Sharma, Comparison of Dose Dependence of Chromosome Aberrations in Peripheral Lymphocytes at Low Levels of Acute in Vitro Irradiation With 250 kV X-Rays and 14 MeV Neutrons, in Proceedings of the International Symposium on Biological Effects of Low-Level Radiation in Venice, pp. 171-184 International Atomic Energy Agency, Vienna, Austria (1983). 

Factory workers exposed for an average of 15 years to acrylonitrile vapors showed no increase in chromosomal aberrations in the peripheral lymphocytes (Thiess and Fleig 1978). As in most human studies, the actual concentration of acrylonitrile to which these workers were exposed was not reported. Flowever, monitoring data indicated that the average exposure concentration for the workers was 5 ppm for the majority of the exposure period (approximately 10 years) at the time the study was conducted, acrylonitrile levels in the workplace had been reduced to 1.5 ppm. 

Human cells exposed to various nickel compounds have an increased frequency of chromosomal aberrations, although sister chromatid exchange frequency is unaffected. Cells from nickel refinery workers exposed to nickel monosulfide (0.2 mg Ni/m3) or nickel subsulfide (0.5 mg Ni/m3) showed a significant increase in the incidence of chromosomal aberrations (Boysen et al. 1980 WHO 1991 USPHS 1993). No correlation was evident between nickel exposure level and the frequency of aberrations (USPHS 1993). 

Populations of soil mites were reduced in the Chernobyl area, but no population showed a catastrophic drop in numbers. By 1987, soil microfauna — even in the most heavily contaminated plots — were comparable to controls. Flies (Drosophila spp.) from various distances from the accident site and bred in the laboratory had higher incidences of dominant lethal mutations (14.7%, estimated dose of 0.8 mGy/h) at sites nearest the accident than controls (4.3%). Fish populations seemed unaffected in July/August 1987, and no grossly deformed individuals were found. However, 34+ i 37( s levels were elevated in young fishes. The most heavily contaminated teleost in May 1987 was the carp (Carassius carassius). But carp showed no evidence of mutagenesis, as judged by incidence of chromosomal aberrations in cells from the corneal epithelium of carp as far as 60 km from Chernobyl (Sokolov et al. 1990). 

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