Showing papers on "Animal mortality published in 1978"

In vitro and in vivo indications of the carcinogenicity and toxicity of food dyes

Abstract: Eight food dyes or commercial color mixtures certified for use in the United States were tested for their ability to transform in vitro a serial line of Fischer rat embryo cells previously reported to be a sensitive indicator of chemicals having carcinogenic potential. Malignant cell transformation was induced by a commercial mixture (G2024) of two of these dyes (Blue 1 and Yellow 5) and by Blue 2, Green 3 (one of two experiments) and Red 4. Food dyes Blue 1, Red 3, Yellow 5 and Yellow 6 did not induce cell transformation. One to 1.5 mg of each dye was injected into suckling LVG or Graffi hamsters which were monitored for tumor induction and/or death over a 330-day period. None of the non-transforming dyes (Blue 1, Red 3, Yellow 5, Yellow 6) or Green 3 induced a significant increase in tumor (mostly lymphoma) incidence or animal mortality. Three of the transforming dyes (Blue 2, Green 2024, Red 4) did increase tumor incidence and/or mortality in at least one strain of hamster. We conclude the the in vitro assay suggested that certain food dyes were carcinogens and that in vivo studies in hamsters supported this interpretation.

Solid tumour models for the assessment of different treatment modalities: VII: single vs fractionated doses of 5-fluorouracil on two solid tumours and their hosts.

Abstract: The effects of one large single dose of 5-fluorouracil (FU) have been compared to the same amount given in divided doses daily over a 3- or 5-day period. Comparison of the effects of single vs fractionated dosage was made on 2 types of experimental solid tumour with different growth, cell kinetic, histological and metastasizing properties. The tumour response was essentially the same for both the single and fractionated dose schedules. There were marked increases in animal mortality from drug toxicity following fractionated doses of FU compared to one large single dose. Mortality in animals with Tumour 3924A increased from 10% following one large single dose to 60% for animals given daily fractionated doses for 3 days, and 80% for animals given daily fractionated doses for 5 days. Total marrow reserve was measured by the total DNA content of tibial marrow. The nadir of 6 days for loss of total tibial marrow DNA following one large dose of FU was increased to 9 days for both fractionated schedules of FU. The 3-day delay in recovery of the marrow prevented recovery within the time frame necessary for animal survival. The inference from these experimental cancer-treatment studies is that daily fractions of chemotherapeutic agents such as FU result in increased morbidity and mortality, without benefit in the control of the solid tumour. The results question the advisability of the clinical practice of initially giving small daily “loading doses” of proliferation-dependent agents such as FU. These results emphasize the need for more precise information on the temporal relationship between the response and recovery of the host and the response and recovery of the solid tumour. They also emphasize the need for a better clinical understanding of the time sequence of solid-tumour recovery in relation to the time sequence of marrow recovery.

Characteristics of Wolf Attacks on Moose in Mount McKinley National Park, Alaska

Abstract: ... The present paper describes attack patterns and wounds inflicted on moose ( Alces alces ) by wolves ( Canus lupus ) and comments on attacks by grizzly bears ( Ursus arctos ) on ungulates in Mount McKinley National Park, Alaska. ...