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Objective: To examine changes occurring in normal pelvic suspensory ligaments (SLs) of horses after denervating these ligaments and to investigate the effect chronic inflammation might have on these changes., Animals: 10 horses., Procedures: The SL of 1 randomly selected pelvic limb of each of 5 horses was injected with collagenase to induce desmitis, and 42 days later, the proximal aspect of both pelvic SLs were denervated. The SLs were harvested 120 days after being denervated, and the morphological and histological characteristics of each collagenase-injected, denervated SL were compared with those of the contralateral, non-injected, denervated SL. All denervated SLs were compared with non-denervated pelvic SLs harvested from 5 horses similar in weight and age., Results: The mean width and the cross-sectional area of the musculature of all denervated SLs were significantly less than that of the non-denervated ligaments. The mean thickness of collagenase-injected denervated ligaments, but not that of the non-injected denervated ligaments, was significantly less than that of the non-denervated ligaments. Histological abnormalities typical of neurogenic muscular atrophy were observed in all denervated ligaments., Clinical Relevance: Loss of motor neuronal input to the proximal aspect of the SL of the pelvic limb of horses causes neurogenic atrophy of the musculature in that portion of the ligament. Denervating a SL of a pelvic limb may weaken the ligament, increasing its risk of injury. Chronic inflammation of the SL before neurectomy may exacerbate atrophy of the musculature after neurectomy.

OBJECTIVE To determine the incidence of incompatible crossmatch results in dogs without a history of prior RBC transfusion and to evaluate changes in Hct following RBC administration for transfusion-naïve dogs that did and did not have crossmatching performed. DESIGN Retrospective study. ANIMALS 169 client-owned dogs. PROCEDURES Information obtained from the medical records included signalment, pretransfusion Hct or PCV, and crossmatching results where applicable. Dogs that underwent major crossmatching (n = 149) as part of pretransfusion screening were each crossmatched with 3 potential donors. Donor blood was obtained from a commercial source and tested negative for dog erythrocyte antigens (DEAs) 1.1, 1.2, and 7 but positive for DEA 4. Mean change in Hct after transfusion was compared between crossmatch-tested dogs (57/91 that subsequently underwent RBC transfusion) and 20 other dogs that underwent RBC transfusion without prior crossmatching by statistical methods. RESULTS 25 of 149 (17%) dogs evaluated by crossmatching were incompatible with 1 or 2 of the 3 potential donors. All 149 dogs were compatible with ≥ 1 potential donor. Mean ± SD change in Hct after transfusion was significantly higher in dogs that had crossmatching performed (12.5 ± 8.6%) than in dogs that did not undergo crossmatching (9.0 ± 4.3%). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated immunologic incompatibility can exist between first-time transfusion recipients and potential blood donor dogs. The clinical importance of these findings could not be evaluated, but considering the potential for immediate or delayed hemolytic transfusion reactions or shortened RBC life span, the authors suggest veterinarians consider crossmatching all dogs prior to transfusion when possible.

OBJECTIVE To determine effects of fentanyl, lidocaine, and a fentanyl-lidocaine combination on the minimum alveolar concentration of sevoflurane preventing motor movement (MAC NM ) in dogs. ANIMALS 6 adult Beagles. PROCEDURES Dogs were anesthetized with sevoflurane in oxygen 3 times (1-week intervals). Baseline MAC NM (MAC NM-B ) was determined starting 45 minutes after induction of anesthesia. Dogs then received 1 of 3 treatments IV: fentanyl (loading dose, 15 μg/kg; constant rate infusion [CRI], 6 μg/kg/h), lidocaine (loading dose, 2 mg/kg; CRI, 6 mg/kg/h), and the fentanyl-lidocaine combination at the same doses. Determination of treatment MAC NM (MAC NM-T ) was initiated 90 minutes after start of the CRI. Venous blood samples were collected at the time of each treatment MAC NM measurement for determination of plasma concentrations of fentanyl and lidocaine. RESULTS Mean ± SEM overall MAC NM-B for the 3 treatments was 2.70 ± 0.27 vol%. The MAC NM decreased from MAC NM-B to MAC NM-T by 39%, 21%, and 55% for fentanyl, lidocaine, and the fentanyl-lidocaine combination, respectively. This decrease differed significantly among treatments. Plasma fentanyl concentration was 3.25 and 2.94 ng/mL for fentanyl and the fentanyl-lidocaine combination, respectively. Plasma lidocaine concentration was 2,570 and 2,417 ng/mL for lidocaine and the fentanyl-lidocaine combination, respectively. Plasma fentanyl and lidocaine concentrations did not differ significantly between fentanyl and the fentanyl-lidocaine combination or between lidocaine and the fentanyl-lidocaine combination. CONCLUSIONS AND CLINICAL RELEVANCE CRIs of fentanyl, lidocaine, and the fentanyl-lidocaine combination at the doses used were associated with clinically important and significant decreases in the MAC NM of sevoflurane in dogs.

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 with 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 probably 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., (© 2015 EVJ Ltd.)

OBJECTIVE To evaluate the effect of MgSO4, alone and in combination with propofol, on the minimum alveolar concentration preventing motor movement (MACNM) in sevoflurane-anesthetized dogs. ANIMALS 6 healthy purpose-bred adult male Beagles (least squares mean ± SEM body weight, 12.0 ± 1.1 kg). PROCEDURES Dogs were anesthetized 3 times at weekly intervals. The MACNM was measured 45 minutes after induction of anesthesia (baseline; MACNM-B) and was determined each time by use of a noxious electrical stimulus. Treatments were administered as a loading dose and constant rate infusion (CRI) as follows: treatment 1, MgSO4 loading dose of 45 mg/kg and CRI of 15 mg/kg/h; treatment 2, propofol loading dose of 4 mg/kg and CRI of 9 mg/kg/h; and treatment 3, MgSO4 and propofol combination (same doses used previously for each drug). A mixed-model ANOVA and Tukey-Kramer tests were used to determine effects of each treatment on the percentage decrease from MACNM-B. Data were reported as least squares mean ± SEM values. RESULTS Decrease from MACNM-B was 3.4 ± 3.1%, 48.3 ± 3.1%, and 50.3 ± 3.1%, for treatments 1, 2, and 3, respectively. The decrease for treatments 2 and 3 was significantly different from that for treatment 1; however, no significant difference existed between results for treatments 2 and 3. CONCLUSIONS AND CLINICAL RELEVANCE MgSO4 did not affect MACNM, nor did it potentiate the effects of propofol on MACNM. Administration of MgSO4 in this study appeared to provide no clinical advantage as an anesthetic adjuvant.

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., (© 2013 Blackwell Publishing Ltd.)

The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MAC(NM)) 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 MAC(NM) (MAC(NM-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 MAC(NM) (MAC(NM-T)) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MAC(NM-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 MAC(NM) in a concentration-dependent manner. The percentage decrease in MAC(NM) 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 MAC(NM). In dogs, propofol decreased the sevoflurane MAC(NM) in a concentration-dependent manner.

We hypothesized that neutrophil function in tumour-bearing dogs is negatively impacted by chemotherapy. Flow cytometric techniques were used to assess neutrophil oxidative burst and phagocytic activities at baseline, 7 and 21 days after induction chemotherapy in 20 dogs with lymphoma. Dogs had a lower percentage of neutrophils exhibiting oxidative burst activity after stimulation with Escherichia coli (day 7; P = 0.009) and phorbol 12-myristate 13-acetate (PMA) (days 7 and 21; P = 0.0003 and P = 0.01, respectively), compared with healthy controls. From day 0 to 7, the percentage of neutrophils exhibiting oxidative burst activity decreased after stimulation with E. coli (P = 0.016) and PMA (P = 0.0006). Induction chemotherapy suppresses the percentage of neutrophils capable of oxidative burst in dogs with lymphoma, with improvement in phagocytic activity over time (P = 0.03). The impact of neutrophil dysfunction on incidence and severity of sepsis in dogs receiving chemotherapy should be investigated., (© 2013 Blackwell Publishing Ltd.)

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., Animals: Ten 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., Results: Hourly (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 Importance: Serum 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., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)

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 < 0.05), and differed (P < 0.05) among treatments. Mean fentanyl plasma concentrations did not differ (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.

Objective: 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., Procedures: Program type, resident evaluations, cumulative surgery and case logs, and scores from ACVO examinations from 2007 to 2010 were evaluated., Results: 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., Conclusions: 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., (© 2013 American College of Veterinary Ophthalmologists.)

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.

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.

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.

Background: Sedation is commonly used during intradermal testing (IDT). Morphine and its derivatives have long been avoided because of their histamine-releasing effects., Hypothesis/objectives: Butorphanol, an opioid agonist/antagonist, will not adversely affect IDT in dogs., Animals: Ten client-owned dogs diagnosed with atopic dermatitis., Methods: 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., Results: 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., Conclusions: 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., (© 2013 ESVD and ACVD.)

Background: 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., Objectives: 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., Animals: Twenty-seven client-owned cats with (n = 12) and without (n = 15) hyperthyroidism were studied., Methods: 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., Results: 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)., Conclusions and Clinical Importance: Altered tyrosine, iodine, and selenium metabolism were not associated with coat color or hyperthyroidism in pointed or light coat-colored cats., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Background: 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., Hypothesis/objectives: 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., Methods: Literature searches for published information on the accuracy of heartworm antigen tests and efficacy of immiticide for treatment of the adult heartworm., Results: 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., Conclusions: 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., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Objective: The objectives of this study were to determine the effects of fentanyl on the end-tidal concentration of sevoflurane needed to prevent motor movement (MACNM ) in response to noxious stimulation, and to evaluate if acute tolerance develops., Study Design: Randomized cross-over experimental study., Animals: Six healthy, adult (2-3 years old), intact male, mixed-breed dogs weighing 16.2 ± 1.1 kg., Methods: Six dogs were randomly assigned to receive one of three separate treatments over a 3 week period. After baseline sevoflurane MACNM (MACNM-B) determination, fentanyl treatments (T) were administered as a loading dose (Ld) and constant rate infusion (CRI) as follows: T1-Ld of 7.5 μg kg(-1) and CRI at 3 μg kg(-1) hour(-1); T2-Ld of 15 μg kg(-1) and CRI at 6.0 μg kg (-1) hour(-1); T3-Ld of 30 μg kg(-1) and CRI at 12 μg kg(-1) hour(-1). The MACNM was defined as the minimum end-tidal sevoflurane concentration preventing motor movement. The first post-treatment MACNM (MACNM-I) determination was initiated 90 minutes after the start of the CRI, and a second MACNM (MACNM - II) determination was initiated 3 hours after MACNM-I was established., Results: The overall least square mean MACNM-B for all groups was 2.66%. All treatments decreased (p < 0.05) MACNM, and the decrease from baseline was 22%, 35% and 41% for T1, T2 and T3, respectively. Percentage change in T1 differed (p < 0.05) from T2 and T3; however, T2 did not differ from T3. MACNM-I was not significantly different from MACNM-II within treatments., Conclusions and Clinical Relevance: Fentanyl doses in the range of 3-12 μg kg(-1) hour(-1) significantly decreased the sevoflurane MACNM. Clinically significant tolerance to fentanyl did not occur under the study conditions., (© 2013 The Authors. Veterinary Anaesthesia and Analgesia © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.)

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 c-kit receptor is responsible for transmission of promigration signals to melanocytes; its downregulation may be involved in malignant progression of human melanocytic neoplasms. Expression of this receptor has not been examined in normal or neoplastic melanocytes from dogs. In this study, 14 benign dermal and 61 malignant mucosal melanocytic tumors were examined for c-kit (KIT) expression. Sites of the mucosal melanomas were gingiva (not further specified; n = 30), buccal gingiva (n = 6), soft palate (n = 4), hard palate (n = 5), tongue (n = 7), lip (n = 6), and conjunctiva (n = 3). Melan A was expressed in all 14 dermal melanocytomas and in 59 of 61 (96.7%) tumors from oral or conjunctival mucosa, confirming melanocytic origin. C-kit receptor expression was strong and diffuse throughout the cytoplasm in all 14 dermal melanocytomas and was identified in basilar mucosal melanocytes over submucosal neoplasms (27 of 61, 44.3%), junctional (neoplastic) melanocytes (17 of 61, 27.9%), and, less commonly, neoplastic melanocytes of the subepithelial tumors (6 of 61, 9.8%). KIT expression anywhere within the resected melanomas correlated with significantly longer survival. These results suggest that c-kit receptor expression may be altered in canine melanomas and may have potential as a prognostic indicator for mucosal melanomas.

Background: The prevalence of meticillin- and multidrug-resistant Staphylococcus pseudintermedius (MRSP) in canine pyoderma has been increasing in recent years; thus, treatment of these cases has become challenging., Hypothesis/objectives: To compare treatment outcome (clinical resolution and treatment duration), adverse effects of medication, and concurrent diseases and medications in dogs with meticillin-susceptible S. pseudintermedius (MSSP) and MRSP pyoderma. ANIMALS/METHODS: Medical records were reviewed retrospectively, and 123 MSSP and 93 MRSP clinical cases between January 2008 and April 2010 were included., Results: In MSSP infections, cefalexin and cefpodoxime were the most commonly prescribed antimicrobials, accounting for 43.2 and 34.4% of cases, respectively. In MRSP infections, chloramphenicol and doxycycline were most commonly prescribed, accounting for 52.6 and 14.4% of cases, respectively. Adverse effects were reported in seven MSSP and 31 MRSP cases. The most commonly reported adverse effects were gastrointestinal, prompting antibiotic discontinuation in three MSSP and 20 MRSP cases. Chloramphenicol was associated with the highest incidence of adverse reactions (27 of 51 cases). Of 164 cases with follow up, 43 of 88 MSSP infections and 29 of 76 MRSP infections achieved complete clinical resolution at the first recheck examination. Three MSSP and seven MRSP cases failed to improve or resolve at subsequent visits assessed at 3-4 week intervals., Conclusions and Clinical Importance: Results from this study showed that the majority of pyodermas resolved regardless of meticillin susceptibility. Although some cases of MRSP pyoderma took longer to treat, this is likely to be because of chronicity and not the organism. In addition, adverse effects were frequently associated with chloramphenicol administration., (© 2012 The Authors. Veterinary Dermatology © 2012 ESVD and ACVD.)

Background: Pituitary pars intermedia dysfunction (PPID) is common in older horses., Objectives: To determine diagnosis frequency, prognostic factors, long-term survival, and owner satisfaction with treatment., Animals: Medical records from horses diagnosed with PPID, 1993-2004., Methods: A retrospective cohort design with data collected from the Veterinary Medical Data Base (VMDB) and a cohort of 3 VTHs. Proportional accessions, annual incidence, and demographics were compared for all accessions. During the same period, a subset of medical records (n = 44) was extracted and owners (n = 34) contacted to obtain long-term follow-up information., Results: Diagnoses of PPID were reported for 217 horses that presented to VTHs and were reported to the VMDB. Proportional diagnosis increased from 0.25/1,000 in 1993 to 3.72/1,000 in 2002. For 44 horses included in the follow-up study, the most commons signs were hirsutism (84%) and laminitis (50%). Of 34 horse owners contacted, the average time from onset of signs to diagnosis was 180 days. Improvement in ≥ 1 signs, 2 months after diagnosis, was reported by 9/22 (41%) of horse owners. Clinical signs and clinicopathologic data were not associated with survival, and 50% of horses were alive 4.6 years after diagnosis. Cause of death among horses (15/20; 85%) was euthanasia, and 11/15 (73%) were euthanized because of conditions associated with PPID. Most horse owners (28/29; 97%) said they would treat a second horse for PPID., Conclusion and Clinical Importance: PPID was diagnosed with increasing frequency, and 50% of horses survived 4.5 years after diagnosis. Owners were satisfied with their horses' quality of life and would treat a second horse if diagnosed., (Copyright © 2012 by the American College of Veterinary Internal Medicine.)

Objective: To investigate the effects of the concurrent administration of 70% N(2)O on the minimum alveolar concentration (MAC) for sevoflurane in dogs, the MAC derivative that blocks motor movement (MAC(NM)), and the MAC derivative that blocks autonomic responses (MAC(BAR))., Animals: 7 adult sexually intact male mixed-breed dogs., Procedures: For each dog, anesthesia was induced with sevoflurane delivered via a face mask. Initially, the baseline MAC, MAC(NM), and MAC(BAR) for sevoflurane were determined by use of a noxious stimulus (50 V, 50 Hz, and 10 milliseconds) applied subcutaneously over a midulnar region. Nitrous oxide (70%) was added to the breathing circuit, and MAC, MAC(NM), and MAC(BAR) were determined again. Percentage changes from the respective baseline concentrations for MAC, MAC(NM)' and MAC(BAR) were calculated after the administration of N(2)O., Results: Baseline median values for the MAC, MAC(NM), and MAC(BAR) for sevoflurane were 1.75%, 2.00%, and 2.50%, respectively. Addition of 70% N(2)O significantly decreased MAC, MAC(NM), and MAC(BAR) by 24.4%, 25.0%, and 35.2%, respectively, and these values did not differ significantly from each other., Conclusions and Clinical Relevance: Supplementation with 70% N(2)O caused a clinically important and significant decrease in the MAC, MAC(NM)' and MAC(BAR) for sevoflurane in dogs.

Objective: To determine the effectiveness of preinduction hyperbaric oxygen treatment (HBOT) in ameliorating signs of experimentally induced endotoxemia in horses., Animals: 18 healthy adult horses., Procedures: Horses were randomly assigned to 1 of 3 equal-sized treatment groups to receive normobaric ambient air and lipopolysaccharide (LPS), HBOT and LPS, or HBOT and physiologic saline (0.9% NaCl) solution. Horses were physically examined, and blood was obtained for a CBC and to determine concentration or activity of plasma tissue necrosis factor-α, blood lactate, and blood glucose before the horses were treated with HBOT and then intermittently for 6 hours after administration of LPS or physiologic saline solution., Results: All LPS-treated horses developed signs and biochemical and hematologic changes consistent with endotoxemia. Treatment with HBOT significantly ameliorated the effect of LPS on clinical endotoxemia score but did not significantly improve other abnormalities associated with endotoxemia., Conclusions and Clinical Relevance: The protective effect of HBOT was minimal, and results did not support its use as a treatment for horses prior to development of endotoxemia.

Two major regional clones of methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been identified in Europe and North America. They are designated multilocus sequence types (ST) 71 and 68 and contain staphylococcal chromosome cassette (SCCmec) types II-III and V(T), respectively. One notable difference between the two clones is a deletion in the mecI/mecR1 regulatory apparatus of ST 68 SCCmec V(T). This deletion in analogous methicillin-resistant Staphylococcus aureus (MRSA) results in more responsive and greater expression of the mecA encoded penicillin-binding protein 2a, and is associated with SCCmec types occurring in community-acquired MRSA lineages. The aim of this study was to characterize mec and bla regulatory apparatuses in MRSP and determine their effects on expression of mecA. Seventeen S. pseudintermedius isolates representing nine methicillin-resistant ST lineages were screened for the presence of the repressors blaI and mecI and sensors blaR1 and mecR1. The bla and mec operons for each isolate were sequenced and compared for homology between the repressor open-reading frames (ORF), sensor ORFs, and mecA promoter regions. A real-time reverse transcriptase PCR expression assay was developed, validated and applied to nine isolates determining the effect of oxacillin induction on mecA transcription. Significant differences were found in mecA expression between isolates with a full regulatory complement (mecI/mecR1 and blaI/blaR1) and those with truncated and/or absent regulatory elements. Isolates representative of European and North American MRSP ST regional clones have dissimilar mecA responses to oxacillin., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Purpose: Mucopolysaccharidosis I (MPS I) is an inherited metabolic disorder resulting from deficiency of α-L-iduronidase and lysosomal accumulation of glycosaminoglycans (GAG) in multiple tissues. Accumulation of GAG in corneal stromal cells causes corneal opacity and reduced vision. The purpose of this study was to determine the extent of ocular GAG accumulation and investigate the effectiveness of intravenous enzyme replacement therapy (ERT) on corneal GAG accumulation in dogs., Methods: Ocular tissues were obtained from 58 dogs with mucopolysaccharidosis I and four unaffected controls. Affected dogs received either low-dose ERT, high-dose ERT, or no treatment; some low-dose dogs also received intrathecal treatments. Histologic severity of corneal stromal GAG accumulation was scored., Results: Accumulation of GAG was found in corneal stromal cells and scleral fibroblasts but not in corneal epithelium, endothelium, ciliary epithelium, choroid, retina, retinal pigment epithelium, or optic nerve. Corneal GAG accumulation increased in severity with increasing age. Although low-dose ERT did not significantly reduce corneal stromal GAG accumulation in comparison with untreated animals, high-dose ERT did result in significantly less GAG accumulation compared with the untreated dogs (adjusted P = 0.0143) or the low-dose ERT group (adjusted P = 0.0031). Intrathecal treatments did not significantly affect GAG accumulation. Dogs that began ERT shortly after birth also had significantly less (P < 0.0001) GAG accumulation in the corneal stroma than dogs with a later onset of treatment., Conclusions: These data suggest that high-dose, intravenous ERT is effective at preventing and/or clearing corneal stromal GAG accumulation, particularly if initiated early after birth.

To comprehensively evaluate the occurrence of renal lesions in a variety of nondomestic felids, necropsy cases from 1978 to 2008 were reviewed from a municipal zoo and a large cat sanctuary for those in which the kidneys were examined histologically. Seventy exotic felids were identified (25 tigers, 18 lions, 6 cougars, 5 leopards, 3 snow leopards, 3 clouded leopards, 3 Canadian lynx, 2 ocelots, 2 bobcats, 2 cheetahs, 1 jaguar), and their histologic renal lesions were evaluated and compared. The most common lesion was tubulointerstitial nephritis (TIN); 36 of 70 (51%) cats were affected to some degree. Lymphocytic interstitial nephritis was the most common lesion in the tigers (9 of 25, 36%) and was rarely seen in other species. Although the renal pelvis was not available for all cats, 28 of 47 (60%) had some degree of lymphocytic pyelitis. There was no significant association between the presence of pyelitis and that of TIN. Only 1 cat had pyelonephritis. Renal papillary necrosis was present in 13 of 70 (19%) cats and was significantly associated with historical nonsteroidal anti-inflammatory drug treatment (odds ratio, 7.1; 95% confidence interval, 1.9 to 26.8). Only 1 cat (lion) had amyloid accumulation, and it was restricted to the corticomedullary junction. Primary glomerular lesions were absent in all cats. Intraepithelial pigment was identified in many of the cats but was not correlated with severity of TIN. Despite several previous reports describing primary glomerular disease or renal amyloidosis in exotic felids, these lesions were rare to absent in this population.

Objective: To determine the possible additive effect of midazolam, a GABA(A) agonist, on the end-tidal concentration of isoflurane that prevents movement (MAC(NM) ) in response to noxious stimulation., Study Design: Randomized cross-over experimental study., Animals: Six healthy, adult intact male, mixed-breed dogs., Methods: After baseline isoflurane MAC(NM) (MAC(NM-B) ) determination, midazolam was administered as a low (LDS), medium (MDS) or high (HDS) dose series of midazolam. Each series consisted of two dose levels, low and high. The LDS was a loading dose (Ld) of 0.2 mg kg(-1) and constant rate infusion (CRI) (2.5 μg kg(-1) minute(-1)) (LDL), followed by an Ld (0.4 mg kg(-1)) and CRI (5 μg kg(-1) minute(-1)) (LDH). The MDS was an Ld (0.8 mg kg(-1)) and CRI (10 μg kg(-1) minute(-1)) (MDL) followed by an Ld (1.6 mg kg(-1)) and CRI (20 μg kg(-1) minute(-1)) (MDH). The HDS was an Ld (3.2 mg kg(-1)) and CRI (40 μg kg(-1) minute(-1)) (HDL) followed by an Ld (6.4 mg kg(-1)) and CRI (80 μg kg(-1) minute(-1)) (HDH). MAC(NM) was re-determined after each dose in each series (MAC(NM-T))., Results: The median MAC(NM-B) was 1.42. MAC(NM-B) did not differ among groups (p > 0.05). Percentage reduction in MAC(NM) was significantly less in the LDS (11 ± 5%) compared with MDS (30 ± 5%) and HDS (32 ± 5%). There was a weak correlation between the plasma midazolam concentration and percentage MAC(NM) reduction (r = 0.36)., Conclusion and Clinical Relevance: Midazolam doses in the range of 10-80 μg kg(-1) minute(-1) significantly reduced the isoflurane MAC(NM) . However, doses greater than 10 μg kg(-1) minute(-1) did not further decrease MAC(NM) indicating a ceiling effect., (© 2011 The Authors. Veterinary Anaesthesia and Analgesia © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.)

Surveillance data indicate that failures have been reported for virtually all heartworm prevention product categories. Resistance of third and fourth stage larvae of Dirofilaria immitis to macrocyclic lactones, lack of compliance, other unknown factors, or a combination of these reasons may be the cause of failure. A survey of members of a national hunting dog club was conducted to identify practices used to prevent canine heartworm infections. Questionnaires were completed by 708 dog owners. Year-round administration of heartworm preventive medication was reported by 208 (88%) respondents residing north of the 37th parallel. Dosing was based on the estimated weight of the dog by 54 (7%) respondents, 389 (55%) did not record the date prophylaxis was administered, and 89 (13%) observed the dogs spit out pills. Heartworm testing at least once per year was done by 556 (79%) respondents and test dates were spread throughout the year. Only 448 (64%) respondents tested newly acquired dogs for heartworm. These findings suggest that veterinarians should place a greater emphasis on the frequency and timing of heartworm diagnostic tests, the importance of weighing dogs, duration of administration, recording the date monthly heartworm prophylaxis is given, and observing dogs to ensure that oral medication is retained.

Objective: To identify practices associated with failure of heartworm prophylaxis among dog and kennel owners and dog trainers., Design: Online survey and mail-in questionnaire. Sample-708 members of a national hunting dog club., Procedures: Heartworm prevention practices used by respondents that reported failure of prophylaxis were compared with practices used by respondents that reported success., Results: Univariate analyses indicated failure of heartworm prophylaxis was inversely related to the number of dogs under a respondent's care. Year-round prophylactic practice was not significantly associated with reduced odds of failure, and efforts to control exposure to mosquitoes were similar among the comparison groups. Respondents reporting prophylaxis failure were more likely to test for heartworm infection ≥ 1 time/y, compared with those reporting success. In a multivariable analysis, residence south of the Virginia-North Carolina state line (ie, the 37th geographic parallel), testing for heartworm infection < once a year when the test was administered prior to April 1, and keeping dogs outdoors for longer periods at dusk, at dawn, or after dark were associated with increased odds of prophylaxis failure., Conclusions and Clinical Relevance: Veterinarians should stress the importance of annual heartworm testing 6 to 7 months after the last possible date of exposure to heartworm, regardless of whether a dog receives prophylactic treatment year-round. Reducing the number of hours dogs spend outdoors at dusk, at dawn, or after dark may reduce the odds of heartworm disease even when dogs are given preventive treatment.

The Food and Drug Administration Center for Veterinary Medicine (FDA/CVM) has cited an increasing number of reports of failure of heartworm prophylaxis in dogs. Failures may be due to resistance of L(3)-L(4) stage Dirofilaria immitis to the macrocyclic lactone class of compounds used for prophylaxis, lack of compliance with and understanding of administration of prophylactics, individual differences in drug absorption or metabolism, or a combination of these factors. Using the latest scientific information, the American Heartworm Society (AHS) and Companion Animal Parasite Council (CAPC) have developed guidelines for the diagnosis, prevention, and treatment of heartworm infection in dogs. This study summarizes the knowledge, beliefs, and behaviors relating to prevention of heartworm among members of a national hunting dog club, visitors to the club website, and attendees at club-sponsored events. These factors can have a direct effect on the success of heartworm prophylaxis. Results suggest that the dog owners lack confidence in the accuracy of the heartworm test to identify infection, the efficacy of products sold for prevention of heartworm, and the effectiveness of treatment to eliminate adult heartworms from infected dogs. Knowledge about when to begin heartworm preventive medication in a new puppy and the timing of heartworm tests was also lacking among a substantial number of respondents. In order to increase acceptance of prophylaxis and reduce the likelihood of a false conclusion of prophylactic failure, education of dog owners should focus on the need for an appropriately timed annual heartworm test and the importance of administering the last dose of monthly heartworm preventative after the last possible day of potential transmission., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Effects of low-dose LPS (0.1 μg/kg i.v.) on leukocyte and platelet parameters measured using an Advia 120 hematology analyzer were investigated. Five dogs received a saline sham treatment prior to LPS, and blood was collected before and 3, 6, and 24 h post-treatment. LPS-treated dogs had mild neutrophil toxic change and increased neutrophil bands at 3 and 6 h. Compared to saline-treated controls, total leukocyte, neutrophil, and monocyte counts of LPS-treated dogs were significantly decreased at 3 h and increased at 24 h. Compared to baseline, total leukocyte counts of LPS-treated dogs were significantly decreased at 3 h and increased at 24 h. Mean platelet volume was significantly increased and mean platelet component concentration was decreased at 3 h compared to baseline. Platelet count was significantly decreased at 3 and 6 h; plateletcrit did not change significantly. High dosage is not required in order to detect LPS-mediated hematologic effects in dogs. Low-dose LPS administration causes significant changes in leukocyte and platelet indices in dogs without causing severe clinical signs or death., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Thirty-two 4-month-old to 19-year-old female miniature pet pigs were spayed. Uterine lesions were present in all except 8 pigs. The 24 remaining pigs had diffuse cystic endometrial hyperplasia, of which 14 had smooth muscle tumors, including leiomyomas and leiomyosarcomas, in the uterus or broad ligament. Nodular endometrial lesions-including adenocarcinomas, adenomas, and/or adenomyosis-were present in 10 pigs, 3 of which had concurrent smooth muscle tumors. Pyometra was present in 3 pigs. In uterine sections with cystic endometrial hyperplasia, adenomyosis, or adenomas, approximately 70% of epithelial nuclei expressed estrogen receptor and progesterone receptor immunohistochemically; in adenocarcinomas, expression was 20%. Regardless of malignancy, more than 50% of nuclei in smooth muscle tumors expressed estrogen receptor and progesterone receptor. Aging was associated with the development of uterine lesions in miniature pet pigs.

Estradiol concentrations are evaluated in canine serum as part of an adrenal panel used to diagnose atypical Cushing's syndrome and other endocrine abnormalities. Estradiol concentrations are often elevated in dogs without clinical signs of hyperestrogenism, and the significance of this elevation is unknown. The purpose of this study was to estimate the variation in estradiol concentrations in normal dogs. Ten neutered male and female dogs were enrolled in the study. Blood was collected from each dog at 2 h intervals, four times during a given day. This was repeated approximately 1 (week 2) and 5 weeks later (week 6). There was no attempt for a given dog to be started at the exact time or day each week. Results showed that estradiol concentrations ranged from 44.6 to 120.3 pg/mL with a mean of 70.4 pg/mL, which is greater than the upper limit of normal for our laboratory (69 pg/mL). The mean difference between the highest and lowest concentrations for each dog was 28.8 pg/mL, with a range of 12.5-53.5 pg/mL. Mean estradiol concentrations from week 6 (63.2 pg/mL) were significantly lower than those from week 1 (71.4 pg/mL; P=0.015) and week 2 (76.5 pg/mL; P=0.0004). These data show a wide range of variability in estradiol concentration both within and between dogs and that these measurements often exceed the normal ranges established by the laboratory. Therefore, diagnosis of hyperestrogenism or atypical Cushing's syndrome based on increased estradiol concentrations should require compatible clinical presentation of hyperestrogenism together with elevated serum estradiol., (© 2010 The Authors. Journal compilation © 2010 ESVD and ACVD.)

Objective: To compare incidence of postoperative complications and survival of horses that had surgery for enterolithiasis of the ascending (AC) or descending (DC) colon., Study Design: Case series, Animals: Horses (n=236) that had celiotomy for AC (n=97) or DC (n=139) enterolithiasis., Methods: Medical records (1999-2005) were reviewed for signalment, presenting clinical signs, surgical findings, postoperative complications, and short-term survival until discharge. Information on performance and survival > or = 1 year was obtained by telephone or mailed questionnaire., Results: Number of postoperative complications did not differ between groups (P=.76). The most frequently identified short-term complications for all horses were incisional problems, gastric ulceration, ileus, diarrhea, fever, and anorexia. Horses with DC enteroliths had a significantly higher incidence of anorexia (P=.04) and fever (P=.01). The most common complications after hospital discharge were incisional problems, laminitis, weight loss, and colic. Although more DC horses were euthanatized intraoperatively (P=.02), no differences were detected for horses that survived until discharge (P=.18) or > or = 1 year after discharge (P=.47)., Conclusions: Number or type of postsurgical complications or survival after surgery was not influenced by enterolith location and horses have a favorable prognosis for long-term survival after enterolith removal, regardless of site of obstruction in the colon., Clinical Relevance: Incidence of postoperative complications and survival are not affected by the site of enterolith obstruction in the colon.

Submissions to the University of Tennessee pathology service from June 1999 to June 2008 were searched for feline cases of tumors involving the eyelids or nictitans. Forty-three tumors were identified. The average age at diagnosis was 10.4 years. Significantly more males than females had eyelid tumors. There were 12 squamous cell carcinomas (SCCs), 11 mast cell tumors (MCTs), 6 hemangiosarcomas (HSAs), 4 adenocarcinomas (ACAs), 3 peripheral nerve sheath tumors (PNSTs), 3 lymphomas, 3 apocrine hidrocystomas (AHCs), and 2 hemangiomas. Cats with MCTs were significantly younger than cats with all other tumor types combined. In contrast, cats with SCCs were significantly older than cats with other tumor types. The HSAs and SCCs were significantly more likely than other tumors to occur in nonpigmented areas. The MCTs, HSAs, AHCs, and hemangiomas did not recur after surgical excision. In contrast, the lymphomas, ACAs, SCCs, and PNSTs frequently recurred and/or resulted in death or euthanasia of the cat. The SCCs were significantly more likely to recur than the MCTs. The average survival time for cats with SCCs was 7.4 months. Although eyelid MCTs have been reported in cats, the prevalence in this study is much higher than previously described.

Objective: To evaluate the effect of IV administration of tramadol hydrochloride on the minimum alveolar concentration of isoflurane (ISOMAC) that prevented purposeful movement of rabbits in response to a noxious stimulus., Animals: Six 6- to 12-month-old female New Zealand White rabbits., Procedures: Anesthesia was induced and maintained with isoflurane in oxygen. A baseline ISOMAC was determined by clamping a pedal digit with sponge forceps until gross purposeful movement was detected or a period of 60 seconds elapsed. Subsequently, tramadol (4.4 mg/kg) was administered IV and the posttreatment ISOMAC (ISOMAC(T)) was measured., Results: Mean +/- SD ISOMAC and ISOMAC(T) values were 2.33 +/- 0.13% and 2.12 +/- 0.17%, respectively. The ISOMAC value decreased by 9 +/- 4% after tramadol was administered. Plasma tramadol and its major metabolite (M1) concentrations at the time of ISOMAC(T) determination varied widely (ranges, 181 to 636 ng/mL and 32 to 61 ng/mL, respectively). Intervals to determination of ISOMAC(T) and plasma tramadol and M1 concentrations were not correlated with percentage change in the ISOMAC. Heart rate decreased significantly immediately after tramadol administration but by 10 minutes afterward was not different from the pretreatment value. Systolic arterial blood pressure decreased to approximately 60 mm Hg for approximately 5 minutes in 3 rabbits after tramadol administration. No adverse effects were detected., Conclusions and Clinical Relevance: As administered, tramadol had a significant but clinically unimportant effect on the ISOMAC in rabbits. Higher doses of tramadol may provide clinically important reductions but may result in a greater degree of cardiovascular depression.

Objective: To evaluate the effect of tramadol on sevoflurane minimum alveolar concentration (MAC(SEVO)) in dogs. It was hypothesized that tramadol would dose-dependently decrease MAC(SEVO)., Study Design: Randomized crossover experimental study., Animals: Six healthy, adult female mixed-breed dogs (24.2 +/- 2.6 kg)., Methods: Each dog was studied on two occasions with a 7-day washout period. Anesthesia was induced using sevoflurane delivered via a mask. Baseline MAC (MAC(B)) was determined starting 45 minutes after tracheal intubation. A noxious stimulus (50 V, 50 Hz, 10 ms) was applied subcutaneously over the mid-humeral area. If purposeful movement occurred, the end-tidal sevoflurane was increased by 0.1%; otherwise, it was decreased by 0.1%, and the stimulus was re-applied after a 20-minute equilibration. After MAC(B) determination, dogs randomly received a tramadol loading dose of either 1.5 mg kg(-1) followed by a continuous rate infusion (CRI) of 1.3 mg kg(-1 )hour(-1) (T1) or 3 mg kg(-1) followed by a 2.6 mg kg(-1 )hour(-1) CRI (T2). Post-treatment MAC determination (MAC(T)) began 45 minutes after starting the CRI. Data were analyzed using a mixed model anova to determine the effect of treatment on percentage change in baseline MAC(SEVO) (p < 0.05)., Results: The MAC(B) values were 1.80 +/- 0.3 and 1.75 +/- 0.2 for T1 and T2, respectively, and did not differ significantly. MAC(T) decreased by 26 +/- 8% for T1 and 36 +/- 12% for T2. However, there was no statistically significant difference in the decrease between the two treatments., Conclusion and Clinical Relevance: Tramadol significantly reduced MAC(SEVO) but this was not dose dependent at the doses studied.

A retrospective study of cases of a unique intramural inflammatory mass within the feline gastrointestinal tract was performed in order to describe and characterize the lesion. Twenty-five cases were identified from archival surgical and postmortem tissues. The lesion most often occurred as an ulcerated intramural mass at the pyloric sphincter (n = 12) or the ileocecocolic junction or colon (n = 9); the remaining cases were in the small intestine. Seven cases also had lymph node involvement. The lesions were characterized by eosinophilic inflammation, large reactive fibroblasts, and trabeculae of dense collagen. Intralesional bacteria were identified in 56% of the cases overall and all of the ileocecocolic junction and colon lesions. Fifty-eight percent of cats tested had peripheral eosinophilia. Cats treated with prednisone had a significantly longer survival time than those receiving other treatments. We propose that this is a unique fibroblastic response of the feline gastrointestinal tract to eosinophilic inflammation that in some cases is associated with bacteria. The lesion is often grossly and sometimes histologically mistaken for neoplasia.

The purpose of this study was to evaluate oestrogen receptor alpha staining in a variety of breeds and skin conditions. The influence of inflammation and coat type on the presence and intensity of oestrogen receptor alpha staining was evaluated. Approximately 1700 haematoxylin and eosin (H&E)-stained slides of skin biopsies were screened for presence of small hair bulbs. Slides from 94 cases were submitted for oestrogen receptor alpha immunohistochemistry. H&E-stained skin biopsy tissues were examined for inflammation and hair follicle stages. Oestrogen receptor alpha staining characteristics of telogen follicles, flame follicles, large anagen bulbs, small hair bulbs and early anagen hairs (capped bulbs) were recorded. To assess the influence of inflammation and coat type on oestrogen receptor staining of hair follicle types, chi-square tests, Fisher's exact tests and logistic regression models were performed. Slides were classified as inflammatory (65) and noninflammatory (29). There were no statistically significant differences in oestrogen receptor staining when comparing inflammatory to noninflammatory skin biopsies or skin biopsies from dogs with different coat types. A subset of 13 noninflammatory biopsies from alopecic skin was identified. There was a statistically significant increase in the number of flame follicles in this subset as compared to all others. Comparison of oestrogen receptor staining of hair follicle types from these biopsies and all other biopsies revealed a statistically significant increase in the number of mature telogen hair follicles stained in this subset. No statistical difference in staining of early follicle stages was noted. Therefore, the oestrogen receptor is unlikely to be the controlling factor for the transition from telogen to anagen in the dog.

Objective: To evaluate sedative, antinociceptive, and physiologic effects of acepromazine and butorphanol during tiletamine-zolazepam (TZ) anesthesia in llamas., Animals: 5 young adult llamas., Procedures: Llamas received each of 5 treatments IM (1-week intervals): A (acepromazine, 0.05 mg/kg), B1 (butorphanol, 0.1 mg/kg), AB (acepromazine, 0.05 mg/kg, and butorphanol, 0.1 mg/kg), B2 (butorphanol, 0.2 mg/kg), or C (saline [0.9% NaCl] solution). Sedation was evaluated during a 30-minute period prior to anesthesia with TZ (2 mg/kg, IM). Anesthesia and recovery characteristics and selected cardiorespiratory variables were recorded at intervals. Antinociception was assessed via a toe-clamp technique., Results: Sedation was not evident following any treatment. Times to sternal and lateral recumbency did not differ among treatments. Duration of lateral recumbency was significantly longer for treatment AB than for treatment C. Duration of antinociception was significantly longer for treatments A and AB, compared with treatment C, and longer for treatment AB, compared with treatment B2. Treatment B1 resulted in a significant decrease in respiratory rate, compared with treatment C. Compared with treatment C, diastolic and mean blood pressures were lower after treatment A. Heart rate was increased with treatment A, compared with treatment B1 or treatment C. Although severe hypoxemia developed in llamas anesthetized with TZ alone and with each treatment-TZ combination, hemoglobin saturation remained high and the hypoxemia was not considered clinically important., Conclusions and Clinical Relevance: Sedation or changes in heart and respiratory rates were not detected with any treatment before administration of TZ. Acepromazine alone and acepromazine with butorphanol (0.1 mg/kg) prolonged the duration of antinociception in TZ-treated llamas.

Evaluation of dogs with splenic masses to better educate owners as to the extent of the disease is a goal of many research studies. We compared the use of ultrasonography (US) and contrast-enhanced computed tomography (CT) to evaluate the accuracy of detecting hepatic neoplasia in dogs with splenic masses, independently, in series, or in parallel. No significant difference was found between US and CT. If the presence or absence of ascites, as detected with US, was used as a pretest probability of disease in our population, the positive predictive value increased to 94% if the tests were run in series, and the negative predictive value increased to 95% if the tests were run in parallel. The study showed that CT combined with US could be a valuable tool in evaluation of dogs with splenic masses.

Objective: To determine the effects of hyperbaric oxygen therapy (HBOT) on full-thickness skin grafts applied to fresh and granulating wounds of horses., Animals: 6 horses., Procedures: On day 0, two 4-cm-diameter circular sections of full-thickness skin were removed from each of 2 randomly selected limbs of each horse, and two 4-cm-diameter circular skin grafts were harvested from the pectoral region. A skin graft was applied to 1 randomly selected wound on each limb, leaving the 2 nongrafted wounds to heal by second intention. On day 7, 2 grafts were harvested from the pectoral region and applied to the granulating wounds, and wounds grafted on day 0 were biopsied. On day 14, 1 wound was created on each of the 2 unwounded limbs, and the wounds that were grafted on day 7 were biopsied. All 4 ungrafted wounds (ie, 2 fresh wounds and 2 wounds with 1-week-old granulation beds) were grafted. The horses then received HBOT for 1 hour daily at 23 PSI for 7 days. On day 21, the grafts applied on day 14 were biopsied., Results: Histologic examination of biopsy specimens revealed that grafts treated with HBOT developed less granulation tissue, edema, and neovascularization, but more inflammation. The superficial portion of the graft was also less viable than the superficial portion of those not treated with HBOT., Conclusions and Clinical Relevance: The use of HBOT after full-thickness skin grafting of uncompromised fresh and granulating wounds of horses is not indicated.

Objective: To determine whether treatment with a preparation of Propionibacterium acnes would improve pregnancy and live foal rates in mares with persistent endometritis., Design: Randomized placebo-controlled clinical trial., Animals: 95 mares with a cytologic diagnosis of persistent endometritis., Procedures: Mares were treated with P acnes or placebo (both administered IV) on days 0, 2, and 6. No attempt was made to alter additional treatments administered by attending veterinarians. Information on breeding history, physical examination findings, results of cytologic examination and microbial culture of uterine samples, additional treatments administered, breeding dates, results of pregnancy examinations, whether a live foal was produced, and reactions to treatment was recorded., Results: In multivariate logistic regression models, mare age, year of entry into the study, and first breeding within 8 days after first treatment with P acnes or placebo were significantly associated with pregnancy. Fewer number of cycles bred and younger age were significantly associated with delivery of a live foal in a separate multivariate analysis. Results of multivariate logistic regression modeling indicated that mares treated with P acnes were more likely to become pregnant and to deliver a live foal, compared with placebo-treated controls., Conclusions and Clinical Relevance: IV administration of P acnes as an adjunct to conventional treatments in mares with a cytologic diagnosis of persistent endometritis improved pregnancy and live foal rates. The optimal effect was detected in mares bred during the interval extending from 2 days before to 8 days after first treatment with P acnes.

Various surgical techniques to correct urovagina in cows describe creating a mucosal extension from the urethral orifice to the labia; however, a fistula often forms in the mucosal extension. The objective of the present study was to determine if the incidence of fistula formation could be decreased by covering transposed submucosal tissue on the dorsal aspect of the urethral extension with a mucosal graft. Cows in both the control group (19) and the experimental group (19) received a modified McKinnon technique of urethral extension; cows in the experimental group also had a sheet of mucosa, obtained from the dorsal aspect of the vestibule, grafted to submucosa exposed during creation of the urethral extension. During histological examination of the biopsy of the graft and its recipient site (harvested 1 week after surgery), neither inosculation nor revascularization of the graft was evident in any sample. Fourteen of 19 (74%) cows in the control group and 10 of 19 (53%) cows in the experimental group developed a fistula in the extension (P=0.18). We concluded that application of a mucosal graft to the subcutaneous tissue exposed to the vestibule using the McKinnon technique of creating a urethral extension was of little or no benefit in preventing the formation of a fistula in the extension. Furthermore, during evaluation of the extensions, digital palpation alone was often insufficient for detection of a fistula.

Objectives: To determine whether transdermal fentanyl patches provided cost-effective post-operative analgesia in dogs with pelvic limb injuries., Study Design: Prospective, randomized, blinded clinical trial., Animals: Twenty-four dogs undergoing repair of ruptured cranial cruciate ligaments or pelvic limb fractures., Methods: Dogs were randomly assigned to one of two groups: those receiving transdermal fentanyl patches (group F) and those receiving injectable morphine for control of post-operative pain (group M). Patients in both treatment groups were monitored for adequacy of analgesia and alterations in physiological variables. Plasma fentanyl concentrations were measured in Group F. Rescue morphine was given if a dog was deemed uncomfortable. The time of first rescue morphine, the total amount, and number of doses of morphine administered over 72 hours was quantified and compared for each group., Results: There was no significant treatment effect on any of the parameters, except for serum cortisol concentration, which was significantly lower overall in group F (p = 0.01). Pain scores peaked at 6 hours post-extubation and were higher than baseline from 2 to 20 hours post-extubation. Cortisol concentrations were the highest at time 0 (extubation) and were significantly higher than baseline until 2 hours post-extubation. Pain scores correlated with fentanyl plasma concentrations (p = 0.0001 and p = 0.01, respectively), but the correlation was low (r = 0.26 and r = 0.16, respectively). No correlation was found between serum cortisol concentrations and pain scores in either group. Fentanyl cost and total cost for pain management were considerably higher for group F., Conclusions: Fentanyl patches did not provide better analgesia or a reduced requirement for rescue opioid compared with intramuscular morphine., Clinical Relevance: When considering overall costs to the client for comparable analgesic intervention, fentanyl patches increased rather than decreased cost during the first 24 hours post-operatively.

The aim of this study was to characterize the pathology and clinical outcome of the subcutaneous variant of canine mast cell tumour. Fifty-three cases satisfying the inclusion criteria were selected from the pathology archive of the College of Veterinary Medicine, University of Tennessee. Referring veterinarians provided information on outcome. These dogs had a median age of 9 years (range 3-17 years). After characterizing tumours histologically, nuclear expression of proliferating cell nuclear antigen (PCNA) and Ki67 (MIB-1 clone) was determined immunohistochemically and mast cell origin was confirmed with c-Kit staining. Counts of argyrophilic nucleolar organizer regions (AgNOR) were determined by silver staining. Nuclear labelling was counted in 100 tumour cells. Margins were recorded as incomplete in 66% of dogs, and metastases occurred in 6% of dogs. The estimated minimum mean survival time from date of diagnosis was 1199 days, ranging from 55 to >1780 days. The median scores from immunohistochemical labelling were PCNA 0.05 and Ki67 0.03 per 100 tumour cells. The median score for AgNOR staining was 1.25 per 100 tumour cells. The patterns of c-Kit expression included membranous labelling in 20 tumours, stippled cytoplasmic labelling in 23 tumours and diffuse cytoplasmic labelling in 10 tumours. Age (r=-0.61, P=0.14) and AgNOR score (r=-0.58, P=0.17) had moderate, but non-significant, negative associations with survival. PCNA (r=-0.32, P=0.47), Ki67 (r=-0.22, P=0.64) and c-Kit immunolabelling was not associated with survival. The subcutaneous variant of canine mast cell tumour is distinct in having features of intermediate histological grade and extended mean survival times, suggesting a slightly better long-term prognosis than for higher grade dermal variants. Expression of nuclear proliferation markers is not associated with outcome.

Objective: To evaluate the effects of i.v. lidocaine (L) and ketamine (K), alone and in combination (LK), on the minimum alveolar concentration (MAC) of isoflurane (ISO) in goats., Study Design: Randomized crossover design., Animals: Eight, adult mixed breed castrated male goats, aged 1-2 years weighing 24-51 kg., Methods: Anesthesia was induced with ISO that was delivered via a mask. The tracheas were intubated and the animals ventilated to maintain an end-tidal carbon dioxide partial pressure between 25 and 30 mmHg (3.3-4 kPa). Baseline MAC (MAC(B)) that prevented purposeful movement in response to clamping a claw was determined in triplicate. After MAC(B) determination, each goat received one of the following treatments, which were administered as a loading (LD) dose followed by a constant rate infusion, IV: L (2.5 mg kg(-1); 100 microg kg(-1) minute(-1)), K (1.5 mg kg(-1); 50 microg kg(-1) minute(-1)), L and K combination or saline, and the MAC (MAC(T)) was re-determined in triplicate. Plasma concentrations of L and K were measured around each MAC point and the values averaged., Results: The least-squares mean MAC(B) for all treatments was 1.13 +/- 0.03%. L, K, and LK reduced (p < 0.05) MAC(B) by 18.3%, 49.6% and 69.4%, respectively. Plasma concentrations for L, K, and LK were 1617 +/- 385, 1535 +/- 251 and 1865 +/- 317/1467 +/- 185 ng mL(-1), respectively. No change (p > 0.05) occurred with saline., Conclusion: Lidocaine and K caused significant decreases in the MAC of ISO. The combination (LK) had an additive effect. However, the plasma L concentrations were less than predicted, as was the MAC reduction with L., Clinical Relevance: The use of L, K and the combination, at the doses studied, will allow a clinically important reduction in the concentration of ISO required to maintain general anesthesia in goats.