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Biomedical subjects

S L Dexter

Publications and source records attributed to S L Dexter.

8 recordsLinked to original sources
PubMed1994

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↗
PubMed1993

Kong toys for laboratory primates: are they really an enrichment or just fomites?

Simple toys as enrichment devices have been associated with a rapid decline in their use by nonhuman primates. Other facets of toy presentation have not been described previously. For example, a comparison of the effect(s) of an enrichment device between two facilities should be validated if enrichment recommendations are to be made that affect diverse research facilities across the country. Additionally, a comparison of two methods of presentation (one highly accessible to the animal and the other less accessible) of the same enrichment device for potential differences in efficacy could provide direction in implementing an enrichment program based on simple toys. The handling of enrichment devices by nonhuman primates can lead to the spread of microbial contamination. The typical enrichment program rotates enrichment devices among animals to maximize the variety of stimuli available to each primate in the most economic manner. An adequate sanitation program is therefore pivotal to minimizing the potential for enrichment devices to be fomites. We conducted three experiments that addressed these issues. The results confirmed that, although the presence of a simple toy reduced behavioral pathology, there was variability in behavioral effect for an enrichment technique between facilities. Two methods of presentation (on floor and suspended) of a simple toy did not produce any significant differences in use. Finally, we demonstrated that microbial growth can persist on enrichment devices after they have been sanitized in a commercial cagewasher.

Animals↗
PubMed1992

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↗
PubMed1984

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↗
PubMed1981

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↗