Comparative Med
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Comparative Study
A single dose of liposome-encapsulated oxymorphone or morphine provides long-term analgesia in an animal model of neuropathic pain.
An extended-release formulation of oxymorphone was produced by encapsulation into liposomes, using a novel technique. Liposome-encapsulated morphine was produced, using a standard technique These preparations were tested in an animal model of neuropathic pain. Male Sprague-Dawley rats (approx. 300 g) were allotted to control (non-loaded liposomes) and treatment (liposome-encapsulated oxymorphone or morphine) groups. ⋯ Non-ligated rats treated with liposome-encapsulated oxymorphone had a small, but significant increase in thermal withdrawal latency from day four through day seven. One subcutaneous injection of liposome-encapsulated oxymorphone or morphine was effective in preventing hyperalgesia in this pain model for up to seven days. These results suggest that liposome-encapsulation of oxymorphone offers a novel, convenient, and effective means to provide long-term analgesia.
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The aim of the study reported here was to assess the prognostic value of gastric tonometry and its implications in the initial phases of hemorrhagic shock. Hemorrhagic shock was induced by use of femoral arterial bleeding in 12 hybrid swine under general anesthesia. Approximately 30% of the circulating blood volume was removed, until mean arterial pressure of 45 mmHg was reached. ⋯ In addition, increase in intramucosal gastric pH (pHi), decrease in the pH-gap (pHa-Hi), and progressive restoration in gastric wall tissue oxygenation (PtO2) also were observed. These results suggest that useful diagnostic and therapeutic indications can be obtained by acquisition of simple hemodynamic measurements at the beginning of the shock period. On the basis of results of statistical analysis, only mean arterial pressure and SVR were good indicators of shock development, whereas pHi was not a significant factor in this experimental model.
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Comparative Study
Relationship of canine bispectral index to multiples of sevoflurane minimal alveolar concentration, using patch or subdermal electrodes.
The purpose of the study reported here was to determine the relationship of bispectral index (BIS) to multiples of sevoflurane minimal alveolar concentration (MAC), using proprietary patch or subdermal needle electrodes in dogs. ⋯ Bispectral index significantly decreased with increasing sevoflurane MAC multiples over the range of 0.8 to 2.0 MAC, using patch or subdermal electrodes in dogs. Use of subdermal needle electrodes is a reliable and practical alternative to use of patch electrodes for measurement of BIS in dogs.
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Comparative Study
Comparison between two types of behavioral variables of non-evoked facial pain after chronic constriction injury to the rat infraorbital nerve.
Chronic constriction injury to the rat infraorbital nerve (IoN-CCI) was reported to induce asymmetric face grooming directed to the territory of the injured nerve, and localized mechanical allodynia. The model has been used for pharmacologic testing; responsiveness to mechanical stimulation has been used as outcome measure, but face grooming behavior was not studied in this context. ⋯ The amount of isolated face grooming is a more sensitive outcome measure of neuropathic pain than is the total amount of face grooming, which includes face grooming during body grooming.