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Biomedical subjects

H G Lloyd

Publications and source records attributed to H G Lloyd.

26 records · Page 2Linked to original sources

Ethylenediamine as a specific releasing agent of gamma-aminobutyric acid in rat striatal slices.

Following incubation with [14C]gamma-aminobutyric acid (GABA) or [3H]dopamine, slices of rat striatum were superfused with media containing 36 mM K+ or ethylenediamine (EDA), 1 or 5 mM. Both K+ and EDA induced a release being largely Ca2+-dependent, while the EDA-induced release was not. Whereas K+ also evoked a Ca2+-dependent release of [3H]dopamine, EDA evoked no release of dopamine. EDA may therefore have potential as a specific GABA releasing agent.

Animals↗

Chronic methylxanthine treatment in rats: a comparison of Wistar and Fischer 344 strains.

Caffeine, theophylline or aminophylline were administered chronically to rats of both sexes, in the weight range 30-245 g. Self-injurious behaviour was noted only rarely in Wistar rats allowed free access to food, but developed over 3 to 4 weeks in half of the animals given a restricted diet of about one third of the intake of control rats. Fischer rats showed self-injurious behaviour more readily, 87% of animals showing signs within 9 days even on an ad lib diet. It is suggested that Fischer rats treated with methylxanthines may provide a model of the Lesch-Nyhan syndrome. Behavioural observations made during the period of methylxanthine treatment suggest that an activation of both the dopamine and 5-hydroxytryptamine neurone systems may be produced. Further work will seek a relationship between these systems and self-injurious behaviour.

Aging↗

Wildlife rabies in Europe and the British situation.

The red fox is considered to be the main reservoir of the present European rabies epizootic which began in Poland in 1939-40. Its usual rate of spread is 20 to 60 km a year. Mortality among rabies-infected fox populations is estimated variously to be 20 to 60%. The infection spreads more rapidly among foxes in the autumn and winter and its occurrence is dependent on fox populations is estimated variously to be 20 to 60%. The infection spreads more rapidly among foxes in the autumn and winter and its occurrence is dependent on fox population densities, it being readily transmitted in populations numbering over one fox to a square kilometre. Subsequently it recurs with a periodicity of three to five years. Though it was described in continental Europe in historic times there is no evidence of dramatic outbreaks among wild carnivores in Britain at any time. Aspects of the behaviour and life history of the fox, pertinent to rabies control are described. Potentially, oral antirabies vaccination of foxes in the wild may be a useful control technique, but there are problems in achieving this. In Britain, quarantine evasion with domestic animals is a significant rabies hazard, which could worsen as the five-sixth area of France still free from rabies becomes infected.

Animals↗