Hamsters, inhalation studies

Likewise, no treatment-related gross reproductive tract alterations after intermediate-duration exposure were observed in male or female rabbits or in male hamsters continuously exposed to aerosols of Fyrquel 220 at concentrations <100 mg/m3 (MacEwen and Vemot 1983). Two male rabbits exposed for 1-4 hours/day, 4-5 days/week, for 11-26 days to 2,000 mg/m3 aerosol of Cellulube 220 (Carpenter et al. 1959) showed no histological evidence for effects on reproductive tissues. No acute or chronic inhalation studies examining reproductive effects in animals were located. 

The toxicity of inhaled triaryl phosphates (triaryl phosphate-mixture), Fyrquel 220, Durad MP280, and cyclotriphosphazene has been well studied in rats, rabbits, and hamsters. These studies suggest that Fyrquel 220 (Gaworski et al. 1986 MacEwen and Vemot 1983), Durad MP280 (Gaworski et al. 1986 ... 

Inhalation studies at the U.S. Air Force Aerospace Medical Research Laboratory showed an increased tumor response (hemangiosarcomas and Kupffer cell sarcomas) in mice exposed at 5 ppm, 6 h/d, 5 d/w for 6 mon (MacEwen and Vernot 1977, and Flaun 1977, reviewed in Trochimowicz 1994). Rats similarly exposed at 5 ppm exhibited increased incidences of squamous cell carcinomas of the lung and hepatocellular carcinomas. Hamsters subjected to a similar experimental protocol failed to show an increased incidence of tumors (MacEwen and Vernot 1975). It must be noted that the 1,1-dimethylhydrazine used in these studies contained 0.12% dimethylnitrosamine, which could be a significant confounder. 

Values for nonaquatic species (e.g., mice, rats, hamsters) were determined from inhalation studies and are given in ppmv ... 

P>[a P has been carcinogenic in all animal species tested to date, including mouse, rat, hamster, rabbit, guinea pig, duck, newt, dog, monkey, and fish. Intratracheal instillation and inhalation studies in a number of species have resulted in elevated incidences of respiratory tract and upper digestive tract tumors, and intraperitoneal and subcutaneous injections... 

Rhabdomyosarcomas developed in rats injected intramuscularly with the powder of either pure cobalt metal or cobalt oxide. In other studies implantation of cobalt caused local fibrosarcomas in rabbits, but inhalation studies in hamsters did not reveal any increase in tumors from cobalt oxide. Lifetime exposure to cobalt sulfate by inhalation resulted in increased incidence of alveolar/bronchiolar neoplasms and a spectrum of inflammatory, flbrotic, and proliferative lesions in the respiratory tract of male and female rats and mice. ... 

In a 2-year inhalation study, there was no evidence of carcinogenicity of methyl methacrylate for male rats exposed at 500 or lOOOppm, for female rats exposed at 250 or 500 ppm, or for male and female mice exposed at 500 or lOOOppm. There was inflammation of the nasal cavity and degeneration of the olfactory sensory epithelium in rats and mice epithelial hyperplasia of the nasal cavity was also observed in exposed mice. In another study no exposure-related tumors were seen in rats or hamsters exposed at 100 and 400 ppm for 24 and 18 months, respectively. " ... 

In inhalation studies with hamsters exposed to 8mg/m at a cumulative dust dose... 

Wehner AP, Stuart BO, Sanders CL. 1979. Inhalation studies with Syrian golden hamsters. Prog Exp Tumor Res 24 177-198. 

Trochimowicz, H.J., Loser, E,. Feron, V.J., Clary, J.J. Valentine, R.R. (1998) Chronic inhalation toxicity and carcinogenicity studies of P-chloroprene in rats and hamsters. Inhal. Toxicol, (in press)... 

Acetaldehyde was tested for carcinogenicity in rats by inhalation exposure and in hamsters by inhalation exposure and intratracheal instillation. Following inhalation exposure, an increased incidence of carcinomas was induced in the nasal mucosa of rats, and laryngeal carcinomas were induced in hamsters. In another inhalation study in hamsters, using a lower exposure level, and in an intratracheal instillation study, no increased incidence of tumours was observed. In hamsters, inhalation of acetaldehyde enhanced the incidence of respiratory-tract tumours produced by intratracheal instillation of benzo a -pyrene (lARC, 1985). 

Isoprene did not induce mutations in bacteria or, in single studies, either sister chromatid exchangess or chromosomal aberrations in cultures of Chinese hamster ovary cells. An inhalation study with mice demonstrated that isoprene could induce sister chromatid exchanges and mieronuclei in bone-marrow cells. No increase in the incidence of chromosomal aberrations was observ ed in the same study. 

Vinylidene chloride was tested for carcinogenicity in mice and rats by oral administration and by inhalation, in mice by subcutaneous administration and by topical application, and in hamsters by inhalation. Studies in mice and rats by oral administration gave negative results. In inhalation studies, no treatment-related neoplasm was observed in rats or hamsters. In mice, a treatment-related increase in the incidence of kidney adenocarcinomas was observed in male mice, as were increases in the incidence of mammary carcinomas in females and of pulmonary adenomas in male and female mice. In skinpainting studies in female mice, vinylidene chloride showed activity as an initiator, but, in a study of repeated skin application, no skin tumom occurred. No tumour at the injection site was seen in mice given repeated subcutaneous administrations (lARC, 1986). 

Morpholine was tested for carcinogenicity by oral administration in two strains of mice, one strain of rats and one strain of hamsters. The studies in one of the strains of mice and in hamsters were considered inadequate for evaluation. In the other strain of mice, no significant increase in the incidence of tumours was seen in treated animals. In the study in rats, a few tumours of the liver and lung occurred in treated animals. Morpholine was also tested by inhalation exposure in rats it did not increase the incidence of tumours over that found in controls (lARC, 1989). 

Klein RG, Schanezer P, Schmahl D. 1987. Long-term inhalation study in Syrian golden hamsters with phthalic acid, bis(2-ethylhexyl)ester (DEHP) in relevant concentrations [abstract], J Cancer Res Clin Oncol 113 S24. 

The vast majority of experimental studies of asbestos have been performed in rodent model systems. Results from inhalation studies indicate that rats are suitable qualitative models for asbestos-induced pulmonary diseases, demonstrating chronic inflammation, pulmonary fibrosis (see Section 3.2.1.2), lung cancer (see Section 3.2.1.8), and mesothelioma (see Section 3.2.1.8) following chronic asbestos exposure. Hamsters seem to be more sensitive than rats to mesothelioma development, but less sensitive to the development of pulmonary tumors (Warheit and Hartsky 1994). 

Hesterberg TW, Axten C, McConnell EE, et al. 1997. Chronic inhalation study of fiberglass and amosite asbestos in hamsters Twelve-month preliminary results. Environ Health Perspect Suppl 105 1223-1229. 

A 52 week chronic inhalation study in hamsters exposed to 1500 ppm acetaldehyde produced growth retardation, slight anemia, increased enzyme and protein content in the urine, and increased kidney weight. There were distinct histopathological changes in the nasal mucosa and trachea, including hyperplasia, squamous cell metaplasia, and inflammation. 

A chronic inhalation study in rats indicates that exposure to 8 ppm acrolein for Ih day for 18 months can result in emphysematous areas in the alveoli. Hamsters exposed to 4 ppm, 1 h day 5... 

No evidence for formaldehyde-induced effects on the skin has been reported in intermediate-duration inhalation studies with rats, hamsters. Rhesus monkeys, or mice (Appelman et al. 1988 Maronpot et al. 1986 Monticello et al. 1989 Woutersen et al. 1987), or in chronic inhalation studies with rats or mice (Kamata et al. 1997 Kems et al. 1983b), except that the highest concentration used in these studies (40 ppm used in the 13-week mouse study by Maronpot et al. 1986) produced severe clinical signs of toxicity in mice including mouth breathing, ataxia, and loss of skin elasticity . 

Thyssen J, Althoff JKG, Mohr U. 1981. Inhalation studies with benzo[a]pyrene in Syrian golden hamsters. J Natl Cancer Inst 66 575-577. 

Becking(41) summarized two inhalation studies of type A sodium zeolite which rapidly decomposes to sodium silicate and amorphous aluminates under physiological conditions. In the first study, hamsters were exposed to approximately 20 mg/m of type A zeolite 3 days per week, 5 hours per day for 52 weeks. In the second study, Cynomolgus monkeys were exposed to 1 and 6 mg/m of type A zeolite for 24 months, and 50 mg/w type A zeolite for 12 months. No evidence of fibrosis was observed in the animals in either study. 

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