Laboratory animals
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The choice of laboratory cage bedding material is often based on both practical and husbandry issues, whereas behavioral outcomes rarely appear to be considered. It has been noted that a breeding success difference appears to be associated with the differential use of aspen chip and aspen shaving bedding in our facility; therefore, we sought to analyze breeding records maintained over a 20-month period. In fact, in all four mouse strains analyzed, shaving bedding was associated with a significant increase in average weanlings per litter relative to chip bedding. ⋯ We found differences in the nests built, but no overall effect of bedding type on the other behaviors examined. Therefore, we argue that breeding success, perhaps especially in more challenging strains, is improved on shaving bedding and this is likely due to improved nest-building potential. For standard laboratory practices, however, these bedding types appear equivalent.
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Mucositis is a common and serious side-effect experienced by cancer patients during treatment with chemotherapeutic agents. Consequently, programmes of research focus on the elucidation of novel therapeutics for alleviation of mucositis symptoms, and these frequently use animal models. However, although these models are assumed to be painful and distressing to the animal, endpoints are difficult to determine. ⋯ Mucositis onset coincided with a decrease in mean burrowing behaviour which was progressive, however this result did not achieve statistical significance (P = 0.66). We conclude that burrowing may be a useful indicator of inflammation in the mucositis model, although this requires further characterization. Pre-selection of animals into treatment groups based on their prior burrowing performance should be pursued in further studies.
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The collection of cerebrospinal fluid is necessary in order to determine its composition. It can then be used to diagnose various diseases. The aim of the study was to develop and optimize a technique for performing safe centesis for the collection of cerebrospinal fluid in piglets and its injection through the cisterna magna. ⋯ The authors identified and confirmed the correspondence of the crista occipitalis and the wings of the atlas with the external landmarks on the cadaver by means of direct radiological visualization. The punctures were performed successfully at the first attempt in 11 out of 12 anaesthetized piglets. The technique herein described provides a reproducible safe and easy route for approaching the cisterna magna for cerebrospinal fluid collection, drug administration and gene delivery.
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Comparative Study
Pressure and volume controlled mechanical ventilation in anaesthetized pregnant sheep.
Optimal mechanical ventilation of the pregnant ewe during anaesthesia is of vital importance for maintaining fetal viability. This study aimed to compare peak inspiratory pressure (PIP), oxygenation and cardiovascular parameters with pressure-control (PCV) or volume-control (VCV) mechanical ventilation of anaesthetized pregnant sheep. Twenty ewes at 110 days gestation underwent general anaesthesia in dorsal recumbency for fetal surgery in a research setting. ⋯ Arterial oxygen tension was higher in the PCV group (P = 0.013). Mean and diastolic pressures were lower in the PCV group (P = 0.029 and P = 0.047, respectively). Both VCV and PCV provide adequate oxygenation of pregnant sheep anaesthetized in dorsal recumbency, though PCV may provide superior oxygenation at a lower PIP.
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The sheep is a popular animal model for human biomechanical research involving invasive surgery on the hind limb. These painful procedures can only be ethically justified with the application of adequate analgesia protocols. Regional anaesthesia as an adjunct to general anaesthesia may markedly improve well-being of these experimental animals during the postoperative period due to a higher analgesic efficacy when compared with systemic drugs, and may therefore reduce stress and consequently the severity of such studies. ⋯ Twenty femoral nerves were located by ultrasound in 10 out of 13 cadavers. In three cadavers, signs of autolysis impeded the scan. This study provides a detailed anatomical description of the localization of the sciatic and the femoral nerves and presents an effective and safe yet simple and rapid technique for performing peripheral nerve blocks with a high success rate.