Ultradian and circadian CO2 emission variations in nocturnal and diurnal animals exposed to a light stimulus.

1. Carbon dioxide emission (VCO2) has been continuously recorded in three laboratory animal species (Sprague-Dawley rats, Japanese quail, Hartley guinea-pigs) which differ by their nocturnal and diurnal activities. A 100 lux stimulus has been delivered at various time intervals.

Age and survival of an acute carbon monoxide intoxication: an animal model.

Pathogen-free OF1 male and female mice of six different ages (between 31 and 387 days), grouped by 10, sex-separated and synchronized by a light (100 lux)-dark 12:12 alternation, were submitted to an acute LD50 carbon monoxide intoxication during the light period during which respiratory and motor activities are at a minimum. For this range of ages carbon monoxide survival is not significantly influenced by age and is significantly (P less than 0.001) less so in males than in females.

Sex-related factors in acute carbon monoxide intoxication in one strain of mice.

In the OF1 mouse strain, males are less resistant than females to acute carbon monoxide intoxication. Castration of males increases their resistance to carbon monoxide. For Neonates injected with four different doses of testosterone (20-500 mg per kg) or oestradiol (2-50 mg per kg), more effect on resistance to carbon monoxide in the (adult) mice was found for oestradiol than for testosterone.

Sex-related factors in acute hypoxia survival in one strain of mice.

In mice of different ages from the OF1 mouse strain, males are less resistant than females to a normobaric hypoxia obtained in a few hours by a progressive lowering of normoxic PO2 with nitrogen flushing. Injection of estradiol to castrated males and spayed females increases hypoxic survival. Neonates which have been injected with a high dose of estradiol show, when adult, a high hypoxic resistance.