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Biomedical subjects

S L Dexter

Publications and source records attributed to S L Dexter.

7 recordsLinked to original sources

Influence of food enrichment on cage side preference.

A preference test paradigm was used to assess the value of two enrichment techniques for rhesus macaques (Macaca mulatta): 1) a Kong toy stuffed with food treats and 2) a fleece board covered with particulate food. The duration of time spent in the enriched cage side was compared with that spent in the unenriched cage side. Additionally, the number of cage side changes made during an observation interval and the duration and frequency of occurrence of select behaviors were recorded. Half the subjects altered their cage side preference during the experimental condition, and a fifth animal reversed side preference in the postexperimental phase. Subjects spent a mean time of 14% of a session engaged with the foraging devices. The occurrence of several behaviors, including self-directed and locomotor activities, varied significantly with the experimental condition. These results were compared with data from a previous preference study of nonnutritive enrichments, and a hypothesis regarding the relative value of different types of enrichment was developed.

Animal Husbandry

Evaluation of the preference to and behavioral effects of an enriched environment on male rhesus monkeys.

Two environments were provided to laboratory rhesus monkeys to determine if the animals spent more time (for the purposes of this study, defined as the cage side preference) in an enriched cage side than an unenriched cage side. The side (right or left) of a double-wide cage in which the animal spent the most time (as determined by Chi square analysis) was initially determined during baseline observations. The "nonpreferred" side was then enriched during the experimental phase of the study. The enrichment consisted of a perch, a Tug-A-Toy suspended inside the cage, a Kong toy suspended on the outside of the cage, and a grooming board mounted on the outside of the cage. No statistically significant changes in use of the enrichments were detected over time. Fifty percent of the animals switched cage side preference to the enriched side during the study. All subjects showed reduced behavioral pathology during exposure to the enriched environment with a return of behavioral pathology when the enrichments were removed.

Animal Husbandry

Zimeldine induced neuropathies.

Zimeldine is recently-introduced antidepressant drug. It has a novel pyridylallylamine structure and acts by selective inhibition of 5-hydroxytryptamine re-uptake at central nerve synapses. This communication reports 2 patients who developed neuropathies within 1 week of starting treatment with this drug. This has hitherto not been described.

Adult

The site of pain origin during migraine attacks.

Fifty patients were examined during a migraine attack to seek the site of origin of the headache. There being no single specific test for an intra-or extracranial source of head pain, we employed a series of manoeuvres: coughing, rapid side-to-side head rotation, and breath-holding for 30 seconds--indicative of an intracranial component. Digital compression of the superficial temporal artery, and a blood pressure cuff round the head to occlude the scalp circulation, were used as evidence of an extracranial component. Patients were asked to comment on the effect each of these procedures had on their headache. The observations suggest that in 49/50 an intracranial factor was operative, and in 21 of these no extracranial component was apparent. In 28/49 there seemed to be both intra- and extracranial contributions to the headache. One patient did not respond to any test. The evidence presented seems to implicate intracranial structures in the pathogenesis of migraine headaches.

Adolescent