Publications (141)204.73 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: The purpose of this study was to evaluate the pharmacokinetics of moxidectin in alpacas after single subcutaneous injection of a non-aqueous formulation or oral administration of an aqueous drench at 0.2 mg*kg-1. Plasma moxidectin concentrations were measured with reverse phase HPLC, and data analyzed using non-compartmental methods.Half-life was longer (p = 0.02) after subcutaneous administration than oral (292 +/- 170 vs 33 +/- 39 h). The area under the concentration-time curve was greater (p = 0.04) following subcutaneous administration (1484.8 +/- 1049.5 h*ng*ml-1) than oral (157.6 +/- 85.9 h*ng*ml-1). The peak concentration (Cmax) was higher and the after subcutaneous administration, but the difference was not statistically significant (p = 0.18). The relative bioavailability of the oral moxidectin to the subcutaneous moxidectin was 11%.The data suggest a higher relative bioavailability following subcutaneous compared to oral administration. Further studies are needed to determine the therapeutic concentrations of moxidectin in alpacas.
- [Show abstract] [Hide abstract] ABSTRACT: Reasons for performing study: Crib-biting is a common oral stereotypy. Although most treatments involve prevention, the efficacy of various anti-crib devices, including surgically implanted gingival rings, has thus far not been empirically tested. Objectives: Demonstrate the effect that 2 anti-crib collars, muzzle, and gingival rings have on crib-biting, other maintenance behaviours, and cortisol levels in established crib-biting horses. Study design: Randomised, crossover clinical trial. Methods: In experiment I, 2 anti-crib collars and a muzzle were used on 8 established crib-biting horses; horses wore each of 3 devices for 7 days, with a 7-day device-free period between treatments. Horses were video recorded for 24 h at least 3 times each week prior to any device placement, and always the day after a device was removed. In experiment II, gingival rings were used in 6 established crib-biting horses; horses were video recorded for 3 days prior to ring implantation and the day after surgery until the rings became ineffective. Plasma cortisol levels were assessed every day during experiment II and on Days 1, 3, and 5 of each week during experiment I. Results: All devices significantly reduced crib-biting compared to control periods. There was no significant difference in crib-bite reduction amongst devices in experiment I, or between pre-device periods and the first day the device was removed. The only increase in plasma cortisol occurred on the day of surgery in experiment II. Conclusions: Common anti-crib devices are effective in reducing crib-biting and significant distress was not evident from our findings. We did not find a post-inhibitory rebound effect. Surgical rings were successful only temporarily and implantation was likely painful to the horses. Because stereotypies involve suboptimal environmental conditions, efforts should be made to improve husbandry factors previously shown to contribute to crib-biting, and research into decreasing horses' motivation to crib-bite should continue. This article is protected by copyright. All rights reserved.
- [Show abstract] [Hide abstract] ABSTRACT: The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MACNM) in dogs subjected to a noxious stimulus using randomized crossover design. Six, healthy, adult beagles (9.2 ± 1.3 kg) were used. Dogs were anesthetized with sevoflurane on 3 occasions, at weekly intervals, and baseline MACNM (MACNM-B) was determined on each occasion. Propofol treatments were administered as loading dose (LD) and constant rate infusion (CRI) as follows: Treatment 1 (T1) was 2 mg/kg body weight (BW) and 4.5 mg/kg BW per hour; T2 was 4 mg/kg BW and 9 mg/kg BW per hour; T3 was 8 mg/kg BW and 18 mg/kg BW per hour, respectively. Treatment MACNM (MACNM-T) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MACNM-T determination for measurement of blood propofol concentration using high-performance liquid chromatography method (HPLC). Data were analyzed using a mixed-model ANOVA and are presented as least square means (LSM) ± standard error of means (SEM). Propofol infusions in the range of 4.5 to 18 mg/kg BW per hour resulted in mean blood concentrations between 1.3 and 4.4 μg/mL, and decreased (P < 0.05) sevoflurane MACNM in a concentration-dependent manner. The percentage decrease in MACNM was 20.5%, 43.0%, and 68.3%, with corresponding blood propofol concentrations of 1.3 ± 0.3 μg/mL, 2.5 ± 0.3 μg/mL, and 4.4 ± 0.3 μg/mL, for T1, T2, and T3, respectively. Venous blood propofol concentrations were strongly correlated (r = 0.855, P < 0.0001) with the decrease in MACNM. In dogs, propofol decreased the sevoflurane MACNM in a concentration-dependent manner.
- [Show abstract] [Hide abstract] ABSTRACT: Objective: To characterize histologic lesions in pigs with and without claw overgrowth. Materials and methods: Hindlimb claws from a subset of 24 sows that were part of a larger field study were selected because of claw deformities associated with overgrowth and change in gait. Length measurements were available for 72 lateral or medial rear claws. Claws were examined histologically and the lesions categorized. Overgrowth was defined as a toe growth measuring > 50 mm in length. Results: Lateral rear claws were most consistently overgrown. However, the distribution and severity of lesions failed to suggest a common etiology for overgrowth. Inflammation, arteriosclerosis, lamellar epithelial changes, phalanx rotation, or combinations of these were not prominent gross or histologic changes. Implications: The pathogenesis of overgrowth in this collection of claws is unknown, but does not appear to represent primary laminitis in this species. As lameness continues to prompt a significant economic loss due to culling, further studies on claw overgrowth, its effect on motion, and its pathogenesis are warranted.
- [Show abstract] [Hide abstract] ABSTRACT: The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MACNM) in dogs subjected to a noxious stimulus using randomized crossover design. Six, healthy, adult beagles (9.2 ± 1.3 kg) were used. Dogs were anesthetized with sevoflurane on 3 occasions, at weekly intervals, and baseline MACNM (MACNM-B) was determined on each occasion. Propofol treatments were administered as loading dose (LD) and constant rate infusion (CRI) as follows: Treatment 1 (T1) was 2 mg/kg body weight (BW) and 4.5 mg/kg BW per hour; T2 was 4 mg/kg BW and 9 mg/kg BW per hour; T3 was 8 mg/kg BW and 18 mg/kg BW per hour, respectively. Treatment MACNM (MACNM-T) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MACNM-T determination for measurement of blood propofol concentration using high-performance liquid chromatography method (HPLC). Data were analyzed using a mixed-model ANOVA and are presented as least square means (LSM) ± standard error of means (SEM).Propofol infusions in the range of 4.5 to 18 mg/kg BW per hour resulted in mean blood concentrations between 1.3 and 4.4 μg/mL, and decreased (P NM in a concentration-dependent manner. The percentage decrease in MACNM was 20.5%, 43.0%, and 68.3%, with corresponding blood propofol concentrations of 1.3 ± 0.3 μg/mL, 2.5 ± 0.3 μg/mL, and 4.4 ± 0.3 μg/mL, for T1, T2, and T3, respectively. Venous blood propofol concentrations were strongly correlated (r = 0.855, P NM. In dogs, propofol decreased the sevoflurane MACNM in a concentration-dependent manner.
- [Show abstract] [Hide abstract] ABSTRACT: Background Atypical hyperadrenocorticism (AHAC) is considered when dogs have clinical signs of hypercortisolemia with normal hyperadrenocorticism screening tests.Hypothesis/Objectives To compare cortisol concentrations and adrenal gland size among dogs with pituitary-dependent hyperadrenocorticism (PDH), atypical hyperadrenocorticism (AHAC), and healthy controls.AnimalsTen healthy dogs, 7 dogs with PDH, and 8 dogs with AHAC.Method Dogs were prospectively enrolled between November 2011 and January 2013. Dogs were diagnosed with PDH or AHAC based on clinical signs and positive screening test results (PDH) or abnormal extended adrenal hormone panel results (AHAC). Transverse adrenal gland measurements were obtained by abdominal ultrasound. Hourly mean cortisol (9 samplings), sum of hourly cortisol measurements and adrenal gland sizes were compared among the 3 groups.ResultsHourly (control, 1.4 ± 0.6 μg/dL; AHAC, 2.9 ± 1.3; PDH, 4.3 ± 1.5) (mean, SD) and sum (control, 11.3 ± 3.3; AHAC, 23.2 ± 7.7; PDH, 34.7 ± 9.9) cortisol concentrations differed significantly between the controls and AHAC (P < .01) and PDH (P < .01) groups. Hourly (P < .01) but not sum (P = .27) cortisol concentrations differed between AHAC and PDH dogs. Average transverse adrenal gland diameter of control dogs (5.3 ± 1.2 mm) was significantly less than dogs with PDH (6.4 ± 1.4; P = .02) and AHAC (7.2 ± 1.5; P < .01); adrenal gland diameter did not differ (P = .18) between dogs with AHAC and PDH.Conclusions and Clinical ImportanceSerum cortisol concentrations in dogs with AHAC were increased compared to controls but less than dogs with PDH, while adrenal gland diameter was similar between dogs with AHAC and PDH. These findings suggest cortisol excess could contribute to the pathophysiology of AHAC.
- [Show abstract] [Hide abstract] ABSTRACT: The study objective was to determine the effects of 70% nitrous oxide (N2O) and fentanyl on the end-tidal concentration of sevoflurane necessary to prevent movement (MACNM) in response to noxious stimulation in dogs. Six healthy, adult, intact male, mixed-breed dogs were used on 3 occasions in a randomized crossover design. After induction of anesthesia with sevoflurane, each of the following treatments was randomly administered: fentanyl loading dose (Ld) of 15 μg/kg and infusion of 6 μg/kg per hour [treatment 1 (T1)], 70% N2O (T2), or fentanyl (Ld of 15 μg/kg and infusion of 6 μg/kg per hour) combined with 70% N2O (T3). Each dog received each of the 3 treatments once during the 3-week period. Determination of MACNM was initiated 90 min after the start of each treatment. The values were compared using the baseline MACNM, which had been determined in a previous study on the same group of dogs. Data were analyzed using a mixed-model analysis of variance (ANOVA) and Tukey-Kramer tests, and expressed as least squares mean ± SEM. The baseline MACNM decreased by 36.6 ± 4.0%, 15.0 ± 4.0%, and 46.0 ± 4.0% for T1, T2, and T3, respectively (P P P ≥ 0.05) between T1 (3.70 ± 0.56 ng/mL) and T3 (3.50 ± 0.56 ng/mL). The combination of fentanyl and N2O resulted in a greater sevoflurane MACNM sparing effect than either treatment alone.
- [Show abstract] [Hide abstract] ABSTRACT: Objective-To compare the 3-D motion of the pelvic limb among clinically normal dogs and dogs with cranial cruciate ligament (CCL)-deficient stifle joints following tibial plateau leveling osteotomy (TPLO) or lateral fabellar-tibial suture (LFS) stabilization by use of an inverse dynamics method. Animals-6 clinically normal dogs and 19 dogs with CCL-deficient stifle joints that had undergone TPLO (n = 13) or LFS (6) stabilization at a mean of 4 and 8 years, respectively, prior to evaluation. Procedures-For all dogs, an inverse dynamics method was used to describe the motion of the pelvic limbs in the sagittal, frontal, and transverse planes. Motion and energy patterns for the hip, stifle, and tibiotarsal (hock) joints in all 3 planes were compared among the 3 groups. Results-Compared with corresponding variables for clinically normal dogs, the hip joint was more extended at the beginning of the stance phase in the sagittal plane for dogs that had a TPLO performed and the maximum power across the stifle joint in the frontal plane was greater for dogs that had an LFS procedure performed. Otherwise, variables in all planes were similar among the 3 groups. Conclusions and Clinical Relevance-Gait characteristics of the pelvic limb did not differ between dogs that underwent TPLO and dogs that underwent an LFS procedure for CCL repair and were similar to those of clinically normal dogs. Both TPLO and LFS successfully provided long-term stabilization of CCL-deficient stifle joints of dogs with minimal alterations in gait.
- [Show abstract] [Hide abstract] ABSTRACT: Objective-To use an inverse dynamics method to describe the motion of the canine pelvic limb in 3 dimensions. Animals-6 healthy adult dogs. Procedures-For each dog, 16 anatomic and tracking markers were used to define the center of rotation for the pelvic limb joints and a kinematic model was created to describe the motion of the pelvic limb. Kinetic, kinematic, and morphometric data were combined so that an inverse dynamics method could be used to define angular displacement, joint moment, and power of the hip, stifle, and tibiotarsal (hock) joints in the sagittal, frontal, and transverse planes. Results-Movement and energy patterns were described for the hip, stifle, and hock joints in the sagittal, frontal, and transverse planes. Conclusions and Clinical Relevance-Knowledge of the 3-D movement of the pelvic limb can be used to better understand its motion, moment, and energy patterns in healthy dogs and provide a referent with which gaits of dogs with pelvic limb injuries before and after surgical repair or rehabilitation can be compared and characterized. This information can then be used to guide decisions regarding treatment options for dogs with pelvic limb injuries.
- [Show abstract] [Hide abstract] ABSTRACT: Incidence of Campylobacter infection exhibits a strong seasonal component and regional variations in temperate climate zones. Forecasting the risk of infection regionally may provide clues to identify sources of transmission affected by temperature and precipitation. The objectives of this study were to (1) assess temporal patterns and differences in campylobacteriosis risk among nine climatic divisions of Georgia, USA, (2) compare univariate forecasting models that analyze campylobacteriosis risk over time with those that incorporate temperature and/or precipitation, and (3) investigate alternatives to supposedly random walk series and non-random occurrences that could be outliers. Temporal patterns of campylobacteriosis risk in Georgia were visually and statistically assessed. Univariate and multivariable forecasting models were used to predict the risk of campylobacteriosis and the coefficient of determination (R 2) was used for evaluating training (1999–2007) and holdout (2008) samples. Statistical control charting and rolling holdout periods were investigated to better understand the effect of outliers and improve forecasts. State and division level campylobacteriosis risk exhibited seasonal patterns with peaks occurring between June and August, and there were significant associations between campylobacteriosis risk, precipitation, and temperature. State and combined division forecasts were better than divisions alone, and models that included climate variables were comparable to univariate models. While rolling holdout techniques did not improve predictive ability, control charting identified high-risk time periods that require further investigation. These findings are important in (1) determining how climatic factors affect environmental sources and reservoirs of Campylobacter spp. and (2) identifying regional spikes in the risk of human Campylobacter infection and their underlying causes.
- [Show abstract] [Hide abstract] ABSTRACT: Squamous cell carcinoma (SCC) is the most common tumor arising in the periocular and penile areas of horses. Both ultraviolet radiation and papillomaviruses have been implicated in the pathogenesis of SCC in various species, including the horse. This retrospective study used polymerase chain reaction (PCR) to detect papillomavirus DNA in archival biopsy samples from equine periocular and penile SCC from 3 different geographic areas (northeast, southeast, and central United States). Forty-two periocular SCCs were tested; none contained papillomavirus DNA. Twenty-two penile SCCs were tested, and papillomavirus DNA was identified in 10 (43%) cases. Sequencing of the PCR products revealed homology with Equus caballus papillomavirus 2 (EcPV-2). No geographic distribution in the detection of papillomavirus was identified. Penile SCCs were significantly more likely to be papillomavirus positive than the periocular SCCs (P < 0.001). The role of papillomavirus in the development of penile SCC requires further investigation. The differing pathogeneses of periocular and penile SCC suggest that the tumors may respond differently to treatment.
- [Show abstract] [Hide abstract] ABSTRACT: Objective To determine the effect of intravenous (IV) buprenorphine on the isoflurane (ISO) minimum alveolar concentration (ISOMAC) in dogs. Study designRandomized, crossover, design. AnimalsSix healthy, adult (2–3 years old), intact dogs (two males and four females) weighing 7.4–11.0 kg. Methods Each dog was studied on three occasions, 1 week apart, and baseline ISOMAC (MACB) was determined on each occasion. ISOMAC was defined as the mean of the end-tidal ISO concentrations that prevented and allowed purposeful movement in response to a noxious stimulus. After MACB determination, dogs were randomly given buprenorphine (BUP) at either 0.01, 0.05 or 0.1 mg kg−1 IV, and ISOMAC was determined at two time periods after BUP administration. The first post-treatment determination (MACT1) was initiated 45 minutes after BUP administration and the second determination (MACT2) was initiated 4 hours after BUP administration. MAC values were determined in duplicate and the mean values were used for statistical analysis. ResultsIsoflurane minimum alveolar concentration was decreased at 141 minutes (the time of MACT1 determination) by 25%, 35%, and 27% after administration of BUP at 0.01, 0.05, and 0.1 mg kg−1, respectively (p ≤ 0.05). The MAC reductions were not statistically different among doses. The reductions in ISOMAC at 342 minutes (the time of MACT2 determination) ranged from 13 to 16%, and were not statistically different among doses. Conclusions and clinical significanceBuprenorphine at 0.01, 0.05, and 0.1 mg kg−1 significantly decreased ISOMAC in dogs at 141 minutes but not at 342 minutes. When using BUP for MAC reduction re-dosing may be required for procedures of long duration, and there may be no advantage to using the 0.1 mg kg−1 dose.
- [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was to examine the association of various aspects of veterinary ophthalmology residency training with the first-time pass rate (FTPR) of the American College of Veterinary Ophthalmologists (ACVO) examination, as well as the individual written, image recognition, animal examination, and surgical sections of the examination. Program type, resident evaluations, cumulative surgery and case logs, and scores from ACVO examinations from 2007 to 2010 were evaluated. Data were available for 71 candidates. The overall FTPR was 35% (n = 25). For the different sections of the examination, FTPRs were as follows: written (68%), image recognition (76%), intraocular surgery (80%), extraocular surgery (65%), and animal examination (75%). The overall FTPR among candidates from academic residency (AR) programs was 43% (20 of 47), while the FTPR of residents in private practice (PPR) programs was 21% (5 of 24; P = 0.07). The AR candidates were more likely to pass the written portion than PPR residents (P = 0.02), and AR candidates had significantly more time off clinics (median 25%) vs PPR residents (median 18%; P = 0.007). The AR residents also had a higher reported percentage of direct supervision than PPR residents (95% vs 76%, respectively). Although PPR residents did significantly more surgeries and examined significantly more dogs and cats, those from ARs examined significantly more equine, bovine, avian, camelid, and reptile species. Overall, AR residents had a higher FTPR and were more likely to pass the written portion of the examination. Total case and surgery numbers were not associated with FTPR.
- [Show abstract] [Hide abstract] ABSTRACT: Sedation is commonly used during intradermal testing (IDT). Morphine and its derivatives have long been avoided because of their histamine-releasing effects. Butorphanol, an opioid agonist/antagonist, will not adversely affect IDT in dogs. Ten client-owned dogs diagnosed with atopic dermatitis. Dogs were randomized to be sedated with butorphanol (0.4 mg/kg) or dexmedetomidine (5 μg/kg). Routine IDT along with intradermal injections of various dilutions of histamine were performed on the lateral thorax, followed 7 days later by the alternative sedative and IDT on the opposite side. The injection sites were subjectively scored and objectively measured by one investigator, blinded to the sedatives, and compared between groups. When the mean wheal diameters from the objective measurements of all antigens, including saline and histamine dilutions, were compared, butorphanol was associated with significantly smaller reactions than dexmedetomidine (P = 0.0001). There was a high level of agreement between sedatives when positive reactions subjectively scored as ≥3+ were compared (κ = 0.91). When mean wheal diameters of histamine at concentrations of 1:100,000, 1:400,000, 1:1,600,000 and 1:6,400,000 were compared, there were no significant differences between sedative types. Moreover, the percentage agreement when comparing subjective interpretation of all histamine dilutions between sedations was high (κ = 0.90). However, there was only 69% agreement beyond chance when objective and subjective interpretations of all antigens were compared between sedative groups. Although butorphanol resulted in significantly smaller wheal size in comparison to dexmedetomidine, it did not affect the overall subjective interpretation of the results of IDT.
- [Show abstract] [Hide abstract] ABSTRACT: Hyperthyroidism is common among older cats, but its pathogenesis remains poorly understood. Siamese and Himalayan cats have a reduced risk of hyperthyroidism compared with domestic short-hair cat breeds. A mechanism of risk reduction in pointed-coat breeds is unknown. To determine if tyrosine, phenylalanine, iodine, or selenium blood concentrations are altered in hyperthyroid cats and to describe the plasma amino acid profiles of client-owned cats with naturally occurring hyperthyroidism. Twenty-seven client-owned cats with (n = 12) and without (n = 15) hyperthyroidism were studied. Cross-sectional study. Hyperthyroid cats were prospectively recruited among cats presenting for radioiodine therapy. Control cats were recruited among pets of hospital personnel. Blood was collected for total thyroxine, plasma amino acid, selenium, and iodine determination. Coat color (8 white or pointed; 19 dark), breed, and diet history were recorded. Tyrosine, phenylalanine, iodine, and selenium levels were not significantly different among light or dark cats or cats with or without hyperthyroidism (P > .05). Plasma amino acid profiles of hyperthyroid cats and control cats were similar, and neither group was deficient in any of the amino acids. l-glutamine was significantly lower in cats with hyperthyroidism (mean ± SD: 648 ± 193) compared with control cats (816 ± 134; P < .05). Altered tyrosine, iodine, and selenium metabolism were not associated with coat color or hyperthyroidism in pointed or light coat-colored cats.
- [Show abstract] [Hide abstract] ABSTRACT: Masitinib mesylate is a tyrosine kinase inhibitor approved for the treatment of gross, non-metastatic grade II and III canine mast cell tumours (MCTs). This study evaluated the use of masitinib as a frontline and rescue agent for metastatic and non-metastatic canine MCTs. Identification of toxicities and prognostic factors in these dogs was of secondary interest. Twenty-six dogs were included in this study. The overall response rate to masitinib was 50%. The median survival time for dogs that responded to masitinib was 630 days versus 137 days for dogs that did not respond (P = 0.0033). Toxicity was recorded in 61.5% of treated dogs, but the majority of adverse events were mild and self-limiting. Response to masitinib, not tumour grade, stage or location, was the most significant prognostic factor for survival in dogs with MCTs.
- [Show abstract] [Hide abstract] ABSTRACT: Food and Drug Administration Center for Veterinary Medicine (FDA/CVM) cited concern regarding failure of heartworm prophylaxis. The positive and negative predictive value of the heartworm antigen test is an estimate of the probability of adult heartworm infection. Assess the sensitivity, specificity, and predictive value of heartworm antigen tests. Explore the role of heartworm test accuracy and treatment with immiticide to generate reports of suspected failure of heartworm prophylaxis. Literature searches for published information on the accuracy of heartworm antigen tests and efficacy of immiticide for treatment of the adult heartworm. Weighted averages for heartworm antigen test sensitivity and specificity were 78.2 and 97.3%, respectively. Efficacy of immiticide by 2-injection or alternate dose protocols were 88.3 and 89.1%, respectively. Depending on prevalence, the positive predictive value of the heartworm antigen test ranged from 15 to 54% and negative predictive value from 99 to 99.9%. For a hospital testing 1,000 dogs per year, false-positive test results may vary from 24 to 27 dogs. If these dogs were on heartworm preventive, they may undergo treatment and be classified as prophylaxis failures. Ten percent of dogs who were treated and continued or placed on prophylaxis at the time of treatment may have adult heartworms when tested 1 year later and be presumed to represent failure of prophylaxis. When interpreting heartworm antigen test results, clinical signs, history, and regional prevalence of heartworm disease should be considered in estimating the predictive value of the test result. Limitations of test and treatment should be discussed with clients as part of the decision-making process.
- [Show abstract] [Hide abstract] ABSTRACT: We evaluated the effect of repeated intraperitoneal administration of tribromoethanol on various parameters in C57BL/6NHsd mice. Mice (n = 68) were randomly assigned to 1 of 7 groups to receive tribromoethanol (500 mg/kg IP) on day 0 or days 0 and 8; vehicle (tert-amyl alcohol in sterile water) only on day 0 or days 0 and 8; sterile water injection on day 0 or days 0 and 8; or no treatment. A single dose of tribromoethanol failed to produce loss of pedal reflex and had no effect on median food and water consumption but altered median body weight on days 1 through 4 when compared with that in mice that received vehicle only or no treatment. Median body weight did not differ between mice that received a single dose of tribromoethanol and those that received an injection of water. Among mice given 2 doses of tribromoethanol, induction time, anesthetic duration, and recovery time varied widely. Repeated administration of tribromoethanol had no effect on median food and water consumption or body weight compared with those in controls. Median liver weight was significantly greater in mice that received 2 doses compared with a single dose of tribromoethanol. Median liver weight did not differ between untreated mice and those that received tribromoethanol. No significant organ or tissue pathology was observed in any study animal. Although tribromoethanol did not produce morbidity, mortality, or pathologic changes in treated animals, we urge caution in use of tribromoethanol in C57BL/6NHsd mice due to its variable anesthetic effectiveness.
- [Show abstract] [Hide abstract] ABSTRACT: This study investigated the effects of 70% nitrous oxide (N2O) on the minimum alveolar concentration (MAC) of isoflurane (ISO) that prevents purposeful movement, the MAC of ISO at which there is no motor movement (MACNM), and the MAC of ISO at which autonomic responses are blocked (MACBAR) in dogs. Six adult, healthy, mixed-breed, intact male dogs were anesthetized with ISO delivered via mask. Baseline MAC, MACNM, and MACBAR of ISO were determined for each dog using a supra-maximal electrical stimulus (50 V, 50 Hz, 10 ms). Nitrous oxide (70%) was then administered and MAC and its derivatives (N2O-MAC, N2O-MACNM, and N2O-MACBAR) were determined using the same methodology. The values for baseline MAC, MACNM, and MACBAR were 1.39 ± 0.14, 1.59 ± 0.10, and 1.72 ± 0.16, respectively. The addition of 70% N2O decreased MAC, MACNM, and MACBAR by 32%, 15%, and 25%, respectively.
The University of Tennessee Medical Center at KnoxvilleKnoxville, Tennessee, United States
Oklahoma State University - StillwaterSWO, Oklahoma, United States
Cornell UniversityИтак, New York, United States
Oklahoma State Department of HealthOklahoma City, Oklahoma, United States