J Am Assoc Lab Anim
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J Am Assoc Lab Anim · Jan 2012
Comparative StudyThromboelastography values from pigtail macaques ( Macaca nemestrina): effects of age and sex.
Thromboelastography is a clinical laboratory test used to assess global hemostasis. With technologic advances and the test's reemergence in human medicine, its utility in veterinary medicine is being explored. Because assays for PT, aPTT, and d-dimers require platelet-poor plasma, whereas thromboelastography is performed on whole blood, thromboelastography provides a more accurate representation of coagulation and allows the identification of hypocoagulable, hypercoagulable, and hyperfibrinolytic states. ⋯ We used a sample of 50 pigtail macaques (Macaca nemestrina) to determine whether age or sex influence thromboelastography values. Of 5 measured and 2 calculated variables produced by thromboelastography, sex had a significant effect only on the lysis-30 parameter, which also showed significant interaction between age and sex; values increased with age in male macaques but decreased with age in female macaques. In addition, we used the data to define reference intervals for thromboelastography parameters in pigtail macaques.
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J Am Assoc Lab Anim · Jan 2012
Using remifentanil in mechanically ventilated rats to provide continuous analgosedation.
Remifentanil is a potent synthetic opioid with sedative effects. Intravenous remifentanil provides deep sedation and analgesia in laboratory animals during experimental procedures. We hypothesized that remifentanil would provide effective analgosedation during assisted mechanical ventilation without affecting respiratory mechanics in rats. ⋯ Similarly, no differences were observed in the tidal volume, respiratory rate and minute ventilation, and gas exchange was equal in all rats at all time points. Frequent assessment of sedation by toe pinch documented loss of the pedal withdrawal reflex in all rats. We conclude that continuous remifentanil infusion provides sufficient analgosedation for mechanically ventilated rats without compromising hemodynamics, respiratory function, or gas exchange.
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J Am Assoc Lab Anim · Jan 2012
Antinociceptive activities of lidocaine and the nav1.8 blocker a803467 in diabetic rats.
The streptozocin-induced diabetic rat is a model of chronic pain that shows signs of hyperalgesia and allodynia and may replicate signs in diabetic humans. Here we investigated the antinociceptive effects of A803467, a highly selective blocker of Nav1.8 channels, in diabetic rats with painful neuropathy. ⋯ Whereas the antihyperalgesic effects of lidocaine and A803467 were similar after intraplantar administration, A803467 (1 mg) was at least 2 times more effective as an antiallodynic than was lidocaine (0.5 mg). These results suggest that compared with lidocaine, systemic or local blockade of Nav1.8 channels by A803467 may more effectively relieve hyperalgesia and allodynia in diabetic neuropathy.
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J Am Assoc Lab Anim · Jan 2012
Sedation or inhalant anesthesia before euthanasia with CO2 does not reduce behavioral or physiologic signs of pain and stress in mice.
CO(2) administration is a common euthanasia method for research mice, yet questions remain regarding whether CO(2) euthanasia is associated with pain and stress. Here we assessed whether premedication with acepromazine, midazolam, or anesthetic induction with isoflurane altered behavioral and physiologic parameters that may reflect pain or stress during CO(2) euthanasia. Mice were assigned to 1 of 6 euthanasia groups: CO(2) only at a flow rate of 1.2 L/min which displaces 20% of the cage volume per minute (V/min; control group); premedication with acepromazine (5 mg/kg), midazolam (5 mg/kg), or saline followed by 20% V/min CO(2); induction with 5% isoflurane followed by greater than 100% V/min CO(2) (>6L/min); and 100% V/min CO(2) only (6 L/min). ⋯ Compared with 20% V/min CO(2) alone, premedication with acepromazine or midazolam did not significantly alter behavior but did induce significantly higher c-fos expression in the brain. Furthermore, the use of isoflurane induction prior to CO(2) euthanasia significantly increased both behavioral and neuromolecular signs of stress. The data indicate that compared with other modalities, 20% V/min CO(2) alone resulted in the least evidence of stress in mice and therefore was the most humane euthanasia method identified in the current study.
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J Am Assoc Lab Anim · Jan 2012
Validity of the modified richmond agitation-sedation scale for use in sedated, mechanically ventilated Swine.
A valid and reliable scale for assessing level of sedation would facilitate appropriate sedation management in a porcine intensive care unit (ICU) model. The Richmond Agitation-Sedation Scale (RASS) is used often for human ICU patients. The purpose of this study was to estimate the content validity of the modified RASS for use in sedated, mechanically ventilated swine. ⋯ The item CVI varied from 0.50 to 0.88; scale CVI was 0.66. Because these values did not meet the a priori criterion, we concluded that the modified RASS does not have sufficient evidence of content validity for use with swine. The reliability of the modified RASS will be tested in the porcine ICU model, and experience with its use in swine will inform refinement of the scale descriptors for repeat assessment of content validity.