Animals, chromosome aberration frequencies

Brooks A, LaBauve R, McClellan R, et al. 1976a. Chromosome aberration frequency in blood lymphocytes cf animals with 239Pu lung burdens. In Radiation and the lymphatic system. National Technical Information Service. Springfield, VA. NTIS no. COMFY-740930. 

The intraperitoneal administration of mercuric chloride at levels comparable to those described above did not induce a clastogenic response in the spermatogonia of the same mouse strain (Poma et al. 1981). Structural chromosome aberrations were not produced in metaphase II oocytes of 15 virgin Syrian hamsters receiving a single intraperitoneal injection of 7.4 mg Hg/kg as methylmercury chloride (Mailhes 1983). However, the frequency of hyperploid cells in the treated animals was significantly (p<0.01) increased compared to the control. A borderline significant increase in hypoploid cells was also seen. 

In an in vivo study with rats, SCCPs, MCCPs and LCCPs did not induce dominant lethal mutations or increase the frequency of chromosomal aberrations in bone marrow cells [1], Another in vivo study with SCCPs showed that when C12 60% Cl was administrated in com oil by gavage to Alpk AP male rats, no effects on unscheduled DNA synthesis in hepatocytes could be detected after exposure for 2 or 12 h [26]. However, a moderate dose- and time-related induction of cell proliferation, measured as S-phase cells in hepatocytes was detected in animals exposed to 1,000 and 2,000 mg/kg for 12 h. 

Lack of chromosomal aberrations has been shown for CPs studied in mammalian cells collected from animal experiments (reviewed in [6]). Sexually mature male Fischer-344 rats administered the SCCP Cio-12 58% Cl by gavage once daily for 5 days at concentrations up to 750 mg/kg/bw/day, did not show an increased mortality or frequency of chromosome or chromatid abnormalities in bone marrow cells [27]. Similarly, no chromosomal aberrations were found for an MCCP (Ci4 i7 52% Cl) in the same experimental design at doses up to 5,000 mg/kg/day [28] or in two LCCP formulations (one with 70% chlorination, the other C22-26, 43% Cl) at doses up to 5,000 mg/kg/day [29, 30]. MRl mice given single doses of 50 and... 

Evidence of chromosomal aberrations was equivocal in an animal study. Rabbits exposed to high natural background levels of radon-222 (12 WLM) for over 28 months displayed an increased frequency of chromosomal aberrations (Leonard et al. 1981). However, when a similar study was conducted under controlled conditions (10.66 WLM), chromosomal aberrations were not found. According to the authors, the increased chromosomal aberrations in somatic cells of rabbits exposed to natural radiation were mainly due to the gamma radiation from sources other than radon. 

Significant sublethal effects of mercury include an increased frequency of cancers, birth defects, and chromosomal aberrations in laboratory animals and wildlife. Adverse sublethal effects of mercurials also include growth inhibition, abnormal reproduction, histopathology, high mercury accumulations and persistence, and disrupted biochemistry, metabolism, and behavior. These - and other aspects of exposure to various mercurials by living organisms - are documented and discussed for representative species of bacteria and other microorganisms, aquatic and terrestrial plants and invertebrates, fishes, amphibians, birds, and mammals. 

An epidemiological study showed no chromosomal aberrations in lymphocytes of normal, caffeine-exposed people, and other studies reported an increased frequency of micronucleated blood cells and the absence of mutagenic compounds in urine. In long-term studies, caffeine was shown to have no carcinogenic potential in rodents. Caffeine has not been classified as carcinogenic in animals or humans by the International Agency for Research on Cancer. 

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