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Biomedical subjects

R G Dawson

Publications and source records attributed to R G Dawson.

13 recordsLinked to original sources
PubMed1986

Lead retention in blood and brain after preweaning low-level lead exposure in the rat.

Newborn rats of the albino Wistar strain were exposed to lead from birth to 20 days of age through mothers milk, from dams which were fed diets containing 0, 0.25, 0.5 or 1.0% powdered lead. Subsequent determination of tissue lead revealed a direct relationship between the lead levels in both blood and brain of the pups and the lead dosage to which they were indirectly exposed via the dams' milk. Lead retention in both tissues was still evident at 100 days of age, with the relative elevation of lead levels being an order of magnitude higher in brain than in blood. There were no obvious signs of lead intoxication in the pups, apart from mild growth retardation in the group with the highest lead burden. However there was a significant retardation in behavioral development observed on two of four measures which were employed. It was concluded that brief exposure to low lead levels in infancy can have long lasting consequences in the brain and in behavior.

Animals↗
PubMed1969

Electroconvulsive shock effects on a reactivated memory trace: further examination.

Rats showed amnesia for conditioned fear training if given an electroconvulsive shock immediately after training. Retention was unimpaired, however, when the electroconvulsive shock treatment was given 1 day after training immediately after the presentation of the stimulus used in the fear conditioning training. These results support the view that electroconvulsive shock disrupts memory trace consolidation but does not disrupt a recently reactivated memory trace.

Animals↗
PubMed1968

Barking, dominance, and territoriality in male sea lions.

Experiments in which male sea lions (Zalophus californianus) were removed and reintroduced into a social group demonstrate that barking by larger males restricts movement and barking by other smaller males. Barking and aggression were primarily directed toward animals of most nearly equal size. Two 6-year-olds seeking to establish and maintain territorial status used aggressive tactics similar to those observed in breeding males in the field.

Aggression↗