Pharmacokinetics of buprenorphine after intravenous administration of clinical doses to dogs

The purpose of this study was to evaluate plasma concentrations and pharmacokinetic parameters of buprenorphine in dogs following intravenous (IV) administration of clinical doses of the opioid. An IV bolus of 0.02 mg/kg buprenorphine was administered to six healthy Beagles and blood samples were collected through a jugular catheter before and at 1, 5, 10, 15, 20, 30 and 45 min, and 1, 2, 4, 6, 8 and 12 h after administration. Plasma buprenorphine concentrations, measured using a commercial radioimmunoassay (RIA), decreased following a three-exponential curve. The two distribution and the elimination half-lives were 2.9 ± 1.8 min, 16.5 ± 3.7 min, and 266.6 ± 82.0 min, respectively; the clearance was 329.6 ± 62.2 mL/min, and the steady state volume of distribution was 83.7 ± 26.5 L.The results demonstrated the feasibility of the RIA assay to analyse buprenorphine in dog plasma samples. Following IV administration buprenorphine showed a three-compartment kinetic profile, as has been described previously in humans, rabbits and cats. The relationship between plasma concentrations and dynamic effects in dogs remains to be established.     

Serum Concentrations of Lidocaine and Its Metabolites MEGX and GX During and After Prolonged Intravenous Infusion of Lidocaine in Horses after Colic Surgery

Lidocaine is the most commonly used prokinetic after gastrointestinal surgery in horses. Cardiovascular status, hepatic function, and duration of therapy are the primary determinants of lidocaine metabolism, and these factors could affect equine patients after colic surgery. This study examined the systemic concentrations of lidocaine and its active metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in horses that had undergone colic surgery and subsequently received prolonged postoperative lidocaine infusions. The mean lidocaine concentration increased over the course of treatment but did not exceed the therapeutic range. Concentrations of MEGX and GX increased progressively, and concentrations exceeding 1,000 ng/ml were observed frequently after 72 hours of infusion. None of the horses in the study developed severe signs of toxicity; however, the progressively increasing concentrations of lidocaine, MEGX, and GX are cause for concern in clinically ill patients receiving prolonged lidocaine therapy. The potential contribution of MEGX and GX should be considered when evaluating adverse reactions to prolonged lidocaine infusions.     

Antinociceptive Effect of Intravenous Regional Analgesia in Horses Underwent Selected Short-Time Distal Limb Surgeries

The aim of the present study was to establish appropriate doses for both lidocaine hydrochloride (Hcl) and mepivacaine in intravenous regional analgesia (IVRA) and to assess their intraoperative and postoperative analgesic effects in horses with distal limb surgeries. A total of 55 draft horses were included in the present study. Six clinically healthy horses were selected randomly for establishing the doses of lidocaine Hcl and mepivacaine in IVRA in horse limbs. After selection, 32 horses suffered from various distal limb surgical affections were randomly allocated into three groups: thiopental group (n = 6), animals were operated under general anesthesia using thiopental sodium; IVRA-LID group (n = 12), animals were operated under both general anesthesia and IVRA using lidocaine Hcl; and IVRA-MEP group (n = 14), horses were operated under both general anesthesia and IVRA using mepivacaine. Postoperative pain was measured using both Horse Grimace Pain Scale and multifactorial numerical rating composite pain. The results showed that conjunction of IVRA along with thiopental general anesthesia using either lidocaine or mepivacaine significantly decreased the total required doses of thiopental sodium during the operations and significantly increased the duration of postoperative analgesia to 60 and 150 minutes using lidocaine and mepivacaine, respectively. In conclusion, the uses of local IVRA before distal limb surgery improve the depth of general anesthesia and reduced postoperative pain, despite thiopental anesthesia alone. Mepivacaine is superior to lidocaine in IVRA, with a longer duration of action.     

Histopathogenesis of experimental Mycobacterium bovis infection in mice

In-bred strains of mice are commonly used to model pathogenic infections due to their cost and utility. In order to understand better the nature of experimental tuberculosis in mice, we infected BALB/c mice with a virulent field isolate of Mycobacterium bovis. Mice were sacrificed at intervals in order to visualise the pathological lesions in major internal organs. Pathological lesions in tissues increased in number and severity over time and replicated many of the salient features observed in badgers and cattle infected with M. bovis. These similarities are discussed. Examination of pathological lesions at terminal stages of infection enabled us to suggest the lethal effects of M. bovis mediated through the host response. We conclude that the mouse is a relevant surrogate species in which to study the virulence of M. bovis, as well as the influence of vaccination on its pathogenicity.     

椰子水的介电性质及其作为输液替代品的可行性

测量了椰子水、生理盐水以及它们的蔗糖溶液在40Hz-40GHz宽频范围的介电弛豫谱(DRS),发现这些体系在高频有一个与水分子的偶极极化引起的介电弛豫,并给出了微观解释。结果表明,椰子水的介电性质主要反映在微波段水分子的极化,且与生理盐水的几乎没有区别。此外,射频段椰子水的电导率与蔗糖含量的依存关系和生理盐水的十分相似,由此给出了椰子水静脉输液功能的介电依据。     

Factors associated with adverse outcomes during parenteral nutrition administration in dogs and cats

Background: Parenteral nutrition (PN) is increasingly used to support hospitalized dogs and cats. Published assessments of outcome are limited. Objective: Evaluate type and prevalence of complications and risk factors for death and complications in dogs and cats receiving PN. Animals: Three hundred and nineteen dogs and 112 cats that received PN at a teaching hospital between 2000 and 2008. Methods: Retrospective case review. Diagnosis, duration of PN administration, concurrent enteral feeding, death, and mechanical, septic, and metabolic complications were abstracted from medical records. Association of each parameter with complications and death was analyzed by binary logistic regression. Results: Pancreatitis was the most common diagnosis (109/319 dogs, 34/112 cats), and 137/319 dogs and 51/112 cats died. Dogs and cats received 113 ± 40% and 103 ± 32% of resting energy requirement, respectively. Mechanical (81/319 dogs, 16/112 cats) and septic (20/319 dogs, 6/112 cats) complications were not associated with death (P > .05). Hyperglycemia was the most common metabolic complication (96/158 dogs, 31/37 cats). Hypercreatininemia in dogs (8/79) was the only complication associated with death (P < .01). Chronic kidney disease in dogs, hepatic lipidosis in cats, and longer duration of inadequate caloric intake before PN in both species were negatively associated with survival (P < .05). Factors positively associated with survival included longer duration of PN administration in both species, enteral feeding in cats with any disease, and enteral feeding in dogs with respiratory disease (P < .05). Conclusions and Clinical Importance: PN can be effectively used to provide the energy requirements of most critically ill dogs and cats. Most complications accompanying PN administration do not affect survival.     

Retrospective evaluation of partial parenteral nutrition in dogs and cats

The purpose of this retrospective study was to evaluate the use of partial parenteral nutrition (PPN) in dogs and cats. The medical records of all dogs and cats receiving PPN between 1994 and 1999 were reviewed to determine signalment, reasons for use of PPN, duration of PPN administration, duration of hospitalization, complications, and mortality. Complications were classified as metabolic, mechanical, or septic. One hundred twenty-seven animals (80 dogs and 47 cats) were included in the study, accounting for 443 patient days of PPN. The most common underlying diseases were pancreatitis (n = 41), gastrointestinal disease (n = 33), and hepatic disease (n = 23). Median time of hospitalization before initiation of PPN was 2.8 days (range, 0.2-10.7 days). Median duration of PPN administration was 3.0 days (range, 0.3-8.8 days). Median duration of hospitalization was 7 days (range, 2-20 days). In the 127 animals receiving PPN, 72 complications occurred. These included metabolic (n = 43), mechanical (n = 25), and septic (n = 4) complications. The most common metabolic complication was hyperglycemia (n = 19), followed by lipemia (n = 17) and hyperbilirubinemia (n = 6). Most complications were mild and did not require discontinuation of PPN. Ninety-three (73.2%) of the 127 patients were discharged. All 4 animals with septic complications were discharged from the hospital. The presence, type, and number of complications did not impact the duration of hospitalization or outcome. However, animals that received supplemental enteral nutrition survived more often than those receiving PPN exclusively. Although PPN seems to be a relatively safe method of providing nutritional support, future studies are warranted to determine its efficacy.