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1.

Objective

To evaluate the onset, magnitude and duration of thermal antinociception after oral administration of two doses of tapentadol in cats.

Study design

Prospective, randomized, blinded, experimental study.

Animals

Six healthy adult cats weighing 4.4 ± 0.4 kg.

Methods

Skin temperature (ST) and thermal threshold (TT) were evaluated using a wireless TT device up to 12 hours after treatment. Treatments included placebo (PBO, 50 mg dextrose anhydrase orally), buprenorphine (BUP, 0.02 mg kg?1) administered intramuscularly, low-dose tapentadol (LowTAP, 25 mg orally; mean 5.7 mg kg?1) and high-dose tapentadol (HighTAP, 50 mg orally; mean 11.4 mg kg?1) in a blinded crossover design with 7 day intervals. Statistical analysis was performed using anova with appropriate post hoc test (p ≤ 0.05).

Results

Salivation was observed immediately following 11 out of 12 treatments with tapentadol. The ST was significantly increased at various time points in the opioid treatments. Hyperthermia (≥ 39.5 °C) was not observed. Baseline TT was 45.4 ± 1.4 °C for all treatments. Maximum TT values were 48.8 ± 4.8 °C at 1 hour in LowTAP, 48.5 ± 3.0 °C at 2 hours in HighTAP and 50.2 ± 5.3 °C at 1 hour in BUP. TT significantly increased after LowTAP at 1 hour, after HighTAP at 1–2 hours, and after BUP at 1–2 hours compared with baseline values. TTs were significantly increased in BUP at 1–2 hours compared with PBO.

Conclusion and clinical relevance

Oral administration of tapentadol increased ST and TT in cats. The durations of thermal antinociception were similar between HighTAP and BUP, both of which were twice as long as that in LowTAP. Studies of different formulations may be necessary before tapentadol can be accepted into feline practice.  相似文献   

2.

Objective

To investigate whether the use of a heat and moisture exchanger (HME) preserves body temperature in dogs weighing <10 kg anaesthetised for magnetic resonance imaging (MRI).

Study design

Prospective, randomised, clinical trial.

Animals

Thirty-one client-owned dogs.

Methods

Dogs were assigned randomly to a treatment group [HME (n = 16) or no HME (n = 15)]. Dogs were pseudorandomised according to the premedication they were administered, either dexmedetomidine or no dexmedetomidine. Induction agents were not standardised. General anaesthesia was maintained with isoflurane vaporised in 100% oxygen delivered using a T-piece and a fresh gas flow of 600 mL kg?1 minute?1. Rectal temperature was measured before premedication (T1), after induction (T2), before moving to the MRI unit (T3) and at the end of the MRI scan (T4). Ambient temperatures were measured in the induction room, outside and inside the MRI unit. Data were analysed using a general linear model with T4 as the outcome variable. Linear correlations were performed between T1, T2, T3 and T4, and variables that predicted T4 were investigated.

Results

Sex, age and body mass were not significantly different between groups. There were no significant differences in rectal temperature between groups at any time point (group with HME at the end of MRI = 36.3 ± 1.1 °C; group with no HME at the end of MRI = 36.2 ± 1.4 °C) but at the end of the MRI, dogs administered dexmedetomidine (36.6 ± 0.7 °C) had a higher rectal temperature compared with dogs not administered dexmedetomidine (35.9 ± 1.6 °C) for premedication. Rectal temperature varied directly with ambient temperature in MRI scanning room and inversely with anaesthetic duration.

Conclusions and clinical relevance

Using an HME did not alter body temperature in dogs weighing <10 kg undergoing an MRI, but including dexmedetomidine in the premedication regimen seemed to preserve the body temperature during anaesthesia.  相似文献   

3.

Objective

To study the feasibility and test–retest repeatability of a sensory threshold examination protocol (STEP) and report the quantitative sensory threshold distributions in healthy dogs.

Study design

Prospective, observational, cohort study.

Animals

Twenty-five healthy client-owned dogs.

Methods

Tactile sensitivity test (TST) (von Frey filaments), mechanical thresholds (MT with 2, 4 and 8 mm probes), heat thresholds (HT) and responsiveness to cold stimulus (CT at 0 °C) were quantitatively assessed for five body areas (BAs; tibias, humeri, neck, thoracolumbar region and abdomen) in a randomized order on three different occasions. Linear mixed model and generalized linear mixed models were used to evaluate the effects of body weight category, age, sex, BA, occasion, feasibility score and investigator experience. Test–retest repeatability was evaluated with the intra-class correlation coefficient.

Results

The STEP lasted 90 minutes without side effects. The BA affected most tests (p ≤ 0.001). Higher thresholds and longer cold latencies were scored in the neck (p ≤ 0.024) compared to other BAs. Weight category affected all thresholds (p ≤ 0.037). Small dogs had lower MT (~1.4 N mean difference) and HT (1.1 °C mean difference) than other dogs (p ≤ 0.029). Young dogs had higher HT than adults (2.2 °C mean difference) (p = 0.035). Gender also affected TST, MT and HT (p < 0.05) (females versus males: TST odds ratio = 0.5, MT = 1.3 N mean difference, HT = 2.2 °C mean difference). Repeatability was substantial to moderate for all tests, but poor for TST. There was no difference in thresholds between occasions, except for CT. Test–retest repeatability was slightly better with the 2 mm MT probe compared to other diameters and improved with operator experience.

Conclusions and clinical relevance

The STEP was feasible, was well tolerated and showed substantial test–retest repeatability in healthy dogs. Further validation is needed in dogs suffering pain.  相似文献   

4.

Introduction

To determine the relationship between aortoseptal angle (AoSA) and the short- and long-term systolic pressure gradient (PG) reduction following combined cutting and high-pressure balloon valvuloplasty (CB/HPBV) in dogs with severe subaortic stenosis.

Animals

Retrospective study of 22 client-owned dogs of various breeds with severe subaortic stenosis (mean left ventricular to aortic PG = 143 mmHg; range = 80–322 mmHg) that underwent CB/HPBV.

Materials and methods

Initial angiographic and left apical and right-sided parasternal long-axis view echocardiographic video loops were used for measuring the angle between the plane of the interventricular septum and the longitudinal axis of the ascending aorta. The PG reduction ratio immediately after CB/HPBV and 6 and 12 months later were compared with AoSA.

Results

Weak correlations were observed for all instances of PG reduction ratio and AoSA type. Significantly greater mean differences of PG reduction ratio were observed for angles >160° than for angles <160° at 24 h (>160° mean: 54.45, standard error [SE]: ±3.8; <160° mean: 39.88, SE: ±2.09), 6 months (>160° mean: 57.73, SE: ±10.9; <160° mean: 28.22, SE: ±3.42), and 12 months (>160° mean: 76.11, SE: ±17.5; <160° mean: 27.61, SE: ±6.44; p=0.003).

Conclusions

Dogs with AoSA >160° on right-sided parasternal long-axis view echocardiograms responded with a greater PG reduction following CB/HPBV than did dogs with AoSA <160°. This suggests that AoSA is associated with long-term outcomes of CB/HPBV, and measurement could help in the evaluation of dogs that are candidates for CB/HPBV.  相似文献   

5.

Objectives

To determine the prevalence of mitral valve regurgitation (MR) in asymptomatic Swedish Norfolk terriers.

Animals

Seventy-nine privately owned Norfolk terriers.

Materials and methods

A prospective observational study was conducted where dogs were recruited via the Swedish Norfolk terrier club. All dogs were examined using the same protocol including physical examination and Doppler echocardiography.

Results

Fifteen dogs (19%) had a murmur at the time of the examination. A total of 35 dogs (44%) had MR, including 23 dogs (29%) with both MR and tricuspid valve regurgitation and 12 dogs (15%) with MR only, identified on Doppler echocardiography. In addition, 7 dogs (9%) had tricuspid valve regurgitation only. The prevalence of MR increased with increasing age (p < 0.0001).

Conclusions

Mitral valve regurgitation is common in asymptomatic Norfolk terriers with and without murmurs and the prevalence increases with age. The impact of MR in this breed on survival remains to be elucidated by a longitudinal study.  相似文献   

6.
7.

Objective

To characterize the pharmacokinetics of dexmedetomidine when administered as a short intravenous (IV) infusion to isoflurane-anesthetized rabbits.

Study design

Experimental study.

Animals

A total of six healthy adult female New Zealand White rabbits.

Methods

Rabbits were anesthetized with isoflurane in oxygen. Following determination of isoflurane minimum alveolar concentration (MAC), the anesthetic dose was reduced to 0.7 × MAC, and dexmedetomidine hydrochloride (20 μg kg?1) was infused IV over 5 minutes. Arterial blood samples were obtained immediately before and at 1, 2, 5, 6, 7, 10, 15, 30, 60, 90, 120, 240 and 360 minutes following termination of the infusion. Samples were transferred into tubes containing ethylenediaminetetraacetic acid and centrifuged immediately. The plasma was harvested and stored at –80 °C until analyzed. Concentrations of dexmedetomidine in plasma were determined by liquid chromatography mass spectrometry. Compartment models were fitted to the time and concentration data using nonlinear regression.

Results

A three-compartment model best fit the data set. Median volume of distribution at steady state and terminal half-life were 3169 mL kg?1 (range, 2182–3859 mL kg?1) and 80 minutes (range, 72–88 minutes), respectively.

Conclusions and clinical relevance

The pharmacokinetics of dexmedetomidine in isoflurane-anesthetized, healthy, New Zealand White rabbits were characterized in this study. Data from this study can be used to determine dosing regimens for dexmedetomidine in isoflurane-anesthetized rabbits.  相似文献   

8.

Objective

To study the effect of heterothermia on anaesthetic drug requirements in semi-free ranging Arabian oryx and to assess the temperature quotient (Q10) of oxygen consumption.

Study design

Prospective observational study and controlled metabolic experiment.

Animals

Sixty-eight anaesthetic events in 59 Arabian oryx from Mahazat As-Sayd protected area, Saudi Arabia

Methods

Anaesthesia was induced by remote injection of 25 mg ketamine, 10 mg midazolam and 0.5 mg medetomidine with a variable amount of etorphine based on a target dosage of 20 μg kg–1 and subjective assessment of body mass. Animals not recumbent within 15 minutes or insufficiently anaesthetized were physically restrained and administered supplementary etorphine intravenously depending on the anaesthetic depth. Body temperature (Tb) was measured rectally immediately upon handling of each animal. From six anaesthetized oryx, expiratory gasses for oxygen analysis and metabolic rate calculation were collected at two Tbs; before and after submersion in ice water for approximately 30 minutes.

Results

Forty-two animals (62%) became recumbent with the initial dose, with a mean induction time (± standard deviation) of 9 ± 2 minutes. The remaining animals could be handled but needed 0.3 ± 0.1 mg etorphine intravenously to reach the desired level of anaesthesia. There was a significant positive correlation between Tb and effective etorphine dosage (R2 = 0.48, p < 0.0001). Average Tb of the six animals in which metabolic rate was measured decreased from 40.0 ± 0.5°C immediately after induction to 35.5 ± 0.5°C after cooling. This reduction was associated with a reduction in oxygen uptake from 3.11 ± 0.33 to 2.22 ± 0.29 mL O2 minute–1 kg–1, reflected in Q10 of 2.17 ± 0.14.

Conclusions and clinical relevance

Tb significantly affects anaesthetic requirements in Arabian oryx and should be considered when selecting dosages for anaesthetic induction for species showing diurnal heterothermy.  相似文献   

9.

Objective

To test the efficacy of intraoperative intrafragmentary administration of bupivacaine (haematoma block) in controlling postoperative pain in dogs undergoing osteosynthesis of long-bone isolated diaphyseal fractures.

Study design

Randomized, ‘blinded’, placebo-controlled, prospective study.

Animals

A total of 23 client-owned dogs with isolated long-bone fractures.

Methods

Dogs were allocated randomly to two groups: bupivacaine group (B) or placebo group (P). Group B dogs (n = 11) were administered an intraoperative intrafragmentary injection of 0.5% bupivacaine (1.1 mg kg–1) just before fracture fixation, whereas group P dogs (n = 12) were administered normal saline. Postoperative pain evaluations using the University of Melbourne Pain Scale (UMPS) and algometer were performed upon arrival to the recovery room and 1, 2, 4, 6, 8, 20 and 32 hours later. Algometer measurements were performed on: the incision site, a healthy region near the fracture line and the contralateral healthy limb. When the pain score exceeded 14 points in the UMPS, rescue analgesia was administered. The time-standardised area under the curve (AUCst) was used to compare UMPS scores and mechanical pain thresholds between the two groups.

Results

None of the group B dogs required rescue analgesia, whereas eight of the 12 group P dogs did (p = 0.001). The pain threshold AUCst at the incision line was higher in group B [16.3 (2.9–41.6) N] than in group P [5.6 (2.5–17.4) N] (p = 0.029). The mean UMPS score AUCst was lower in group B (3.7 ± 1.8) than in group P (9.4 ± 4.6) (p = 0.016). In a small number of animals of both groups that were evaluated radiologically, adequate bone healing was noted.

Conclusions and clinical relevance

An intraoperative bupivacaine haematoma block is a simple, quick and effective method that can be used to aid in postoperative pain control in dogs submitted to long-bone osteosynthesis.  相似文献   

10.

Objective

To determine the anti-inflammatory efficacy of choline in vivo and in vitro and to investigate the anti-inflammatory mechanisms of choline.

Study design

Randomized, controlled studies.

Animals

In vivo trials used 16 Romney sheep. In vitro experiments utilized RAW 264.7 mouse macrophage cells.

Methods

Hypoxaemia induced in 16 sheep by intravenous (IV) injection of 50 μg kg–1 xylazine, an α-2 agonist, was measured in sheep at 0, 1 and 4 minutes using arterial blood gas analysis with and without 50 mg kg–1 IV choline chloride premedication. Cell culture studies used enzyme-linked immunosorbent assay to measure the release of tumour necrosis factor (TNF-α) from lipopolysaccharide (LPS) stimulated macrophages with and without choline chloride premedication. TNF-α release was compared to thalidomide suppressed and untreated cells.

Results

Choline premedication in sheep mitigated a reduction in arterial partial pressure of oxygen (PaO2) but did not prevent development of clinically significant hypoxaemia. Decrease in mean PaO2 of choline treated sheep was 6.36 kPa (47.7 mmHg) compared to 9.81 kPa (73.6 mmHg) in control sheep. In vitro studies demonstrate that choline administered concurrent with LPS activation did not significantly suppress TNF-α expression but that treatment of cells with choline 10 minutes prior to LPS activation did significantly suppress TNF-α expression. Choline pretreated cells expressed 23.99 ± 4.52 ng mg–1 TNF-α while LPS only control cells expressed 33.83 ± 3.20 ng mg–1.

Conclusions

Choline is able to prevent macrophage activation in vitro when administered prior to LPS activation and may reduce hypoxaemia in sheep developing pulmonary oedema after xylazine administration. This effect requires premedication with choline.

Clinical relevance

Pharmacological manipulation of autonomic inflammatory responses holds promise for the treatment of inflammation. However, the complex cellular mechanisms involved in this reflex means that an adequate therapy should approach multiple pathways and mechanisms of the inflammatory response.  相似文献   

11.

Objective

To describe a transorbital approach to the maxillary nerve block in dogs and compare it with a traditional approach.

Study design

Prospective, randomized controlled study.

Animals

Heads from 17 euthanized dogs (10 Greyhounds, three Border Collies and four of mixed breed).

Methods

A volume of 1 mL of methylene blue dye was injected by each of two techniques, a traditional percutaneous approach and a transorbital approach to the maxillary nerve block. Both techniques were used on each head, alternating the left and right sides after random assignment to the first head. The heads were dissected to reveal the maxillary nerve and the length of nerve stained was measured.

Results

There was no significant difference (p = 0.67) in the proportion of nerves stained for a length >6 mm by either technique (88.2% transorbital versus 82.3% percutaneous). The mean length of nerve stained did not differ significantly between the techniques (p = 0.26).

Conclusions and clinical relevance

The transorbital approach to the maxillary nerve block described here presents a viable alternative to the traditional percutaneous approach. Further study is required to confirm its efficacy and safety under clinical conditions.  相似文献   

12.

Objective

To evaluate the efficacy, in terms of the amount of rescue analgesia required, and the clinical usefulness of epidural injection of morphine with bupivacaine or levobupivacaine for elective pelvic limb surgery in dogs during a 24-hour perioperative period.

Study design

Prospective, blinded, randomized clinical study.

Animals

A group of 26 dogs weighing 31.7 ± 14.2 (mean ± standard deviation) kg and aged 54 ± 36 months.

Methods

All dogs were premedicated with methadone intravenously (0.2 mg kg–1) and anaesthesia induced with diazepam (0.2 mg kg–1) and propofol intravenously to effect. After induction of anaesthesia, dogs randomly received a lumbosacral epidural injection of morphine 0.1 mg kg–1 with either levobupivacaine 0.5% (1 mg kg–1; group LevoBM) or bupivacaine 0.5% (1 mg kg–1; group BM). Cardiovascular, respiratory and temperature values were recorded during the intra- and postoperative period. A visual analogue scale, subjective pain scale, sedation scale and the short form of the Glasgow pain scale were assessed every 6 hours after epidural injection during 24 hours. The ability to stand and walk, neurological deficits and other side effects were assessed at the same time points. The amount of rescue analgesia (sufentanil intraoperatively and methadone postoperatively) was recorded.

Results

No statistically significant differences were found between groups for any of the recorded data, with the exception of the incidence of spontaneous urination and postoperative rescue analgesia requirement. In group LevoBM four dogs spontaneously urinated at recovery while none of the dogs in group BM did (p = 0.03) and seven dogs of group LevoBM required postoperative rescue analgesia versus none of the dogs in the BM group (p = 0.005).

Conclusions

and clinical relevance Epidural LevoBM is a suitable alternative to BM in healthy dogs during elective pelvic limb surgery. Epidural BM produced more urinary retention but better pain control compared to the same concentration and dose of LevoBM in dogs.  相似文献   

13.

Objective

To evaluate replicate effects and test–retest reliability of mechanical and thermal quantitative sensory testing (QST) in normal dogs and dogs with osteoarthritis (OA)-associated pain.

Study design

A prospective clinical study.

Animals

A total of 54 client owned dogs (OA, n = 31; controls, n = 23).

Methods

Mechanical [electronic von Frey (EVF) and blunt pressure] and thermal (hot and cold) sensory thresholds were obtained in dogs with OA-associated pain and control dogs at two visits, 7 days apart, to assess test–retest reliability. Thresholds were measured at the OA-affected joint (hip or stifle), over the tibial muscle and over the midpoint of the metatarsals. Five replicates were obtained for each modality at each site bilaterally.

Results

Overall, there was no significant effect of replicates on QST response. EVF thresholds were significantly lower at the second visit in OA dogs at the affected and metatarsal sites (p = 0.0017 and p = 0.0014, respectively). Similarly for control dogs, EVF thresholds were significantly lower at the second visit at the metatarsal site (p = 0.001). Significantly higher hot thermal latencies were seen in OA dogs at the affected and tibial testing sites (p = 0.014 and p = 0.012, respectively), and in control dogs at the tibial site (p = 0.004).

Conclusions

In QST, a replicate does not show a strong effect. However, QST results show variability over time, particularly for EVF and hot thermal stimuli.

Clinical relevance

If QST is to be used clinically to evaluate a sensitized state, the variability over time needs to be accounted for in the study design.  相似文献   

14.

Background

Increased cardiac troponin I (cTnI) concentration has been reported in dogs with atrioventricular (AV) block before and shortly following pacemaker implantation. The role of AV dyssynchrony, age, or concurrent cardiac disease on cTnI concentration remains unknown.

Objectives

To investigate change in cTnI concentration following dual-chamber pacemaker implantation on short- and long-term follow-up and to compare cTnI values to a case-matched control group.

Animals

Thirty-eight client-owned dogs with permanent AV block and 38 matched control dogs.

Methods

Retrospective review of medical records. Pacemaker group consisted of dogs with AV block and dual-chamber pacing. Control group matched the study population in age and cardiac disease. cTnI was compared between pacemaker and control group on short- and long-term follow-up. Different lead types and influence of arrhythmia on cTnI were tested.

Results

cTnI was high at presentation (median 0.66 ng/ml; range 0.03–18.6) and showed a significant reduction over time after pacemaker implantation (p < 0.0001). Median cTnI values were significantly different between pacemaker and control group on short-term (p = 0.0004; 0.11 ng/ml, range 0.03–1.36 versus 0.06 ng/ml, range 0.03–0.46), but not on long-term follow-up (p = 0.0547; 0.14 ng/ml, range 0.03–0.73 versus 0.07 ng/ml, range 0.03–0.46). Lead type and severity of arrhythmia did not show a significant correlation to cTnI concentration.

Conclusions

On long-term follow-up, cTnI remained mildly elevated in some of the pacemaker dogs but was not significantly different to the matched control group.  相似文献   

15.

Objectives

To investigate whether acupuncture can alter gait in horses as assessed by objective and subjective parameters.

Study design

Prospective, randomized, singleblinded, crossover study.

Animals

Eight adult horses.

Methods

Horses were randomly assigned to a treatment (three acupuncture treatments in 8 days) or control group. Subjective and objective gait analyses were performed before and after each treatment and at 1, 3 and 7 days after the last treatment (time-points 1–9, respectively). Horses were assessed at the trot in a straight line on a hard surface and on the lunge on the left and right reins on a soft surface (conditions 1–3, respectively). After 12 weeks, groups were reversed. Objective gait analysis was performed using inertial sensors and subjective analysis by two board- certified surgeons who reviewed video-recordings. Each limb was assessed for lameness before and after treatment. Lameness and global scores were assigned using 4-point scales. Assessors were blinded to treatment status. The effects of treatment (yes/no), time (1–9) and horse under conditions 1 –3 were compared using a linear mixed-effects model and a generalized estimating equation.

Results

Treatment decreased hip hike difference under all conditions [condition 1: control, 6.3 ± 6.4 mm versus treatment, –0.2 ± 6.4 mm (p = 0.007); condition 2: control, 9.7 ± 7.8 mm versus treatment, 2.8 ± 7.8 mm (p = 0.032); condition 3: control, 7.3 ± 6.3 mm versus treatment, –2.7 ± 6.4 mm (p = 0.003)]. Other parameters also improved significantly under conditions 1 and 3. Based on subjective gait analysis, treatment decreased lameness [odds ratio (OR) 0.51, 95% confidence interval (CI) 0.34–0.78; p = 0.002] but not global (OR 0.53, 95% CI 0.24–1.10; p = 0.12) scores.

Conclusions and clinical relevance

Acupuncture can change horses' gaits to a degree appreciable by objective and subjective analyses.  相似文献   

16.

Objective

To evaluate the efficacy of a vapocoolant spray to provide local anaesthesia for calves during ear tagging and ear notching.

Study design

Randomized study.

Animals

Twenty Black Angus calves aged 4–16 weeks old.

Methods

Temperature validation studies using thermocouples and a temperature data logger were conducted on dead and live tissue to determine optimal spray distance and duration to achieve tissue anaesthesia (<10 °C). A behavioural trial was conducted to assess efficacy for ear tagging and ear notching. Calves (n = 20) were randomly assigned to the vapocoolant spray (VS) or the water spray (WS) group. A 3 second spray was administered from 10 cm to both sides of the ear immediately prior to ear tagging and ear notching. A numerical rating scale (NRS) was used to score behavioural response to each procedure, with responses categorized from 0 (no response) to 3 (severe).

Results

Temperature and tissue validation studies indicated that a vapocoolant spray reduced dead and live tissue temperature to below nociceptive threshold levels (10 °C) for 10–16 seconds. Univariate analysis indicated that ear notching was more painful than ear tagging [odds ratio (OR) = 19.2, 95% confidence interval (CI): 5.34–68.99, p < 0.001]. When adjusted for the multivariate model, there was a significant effect of treatment, with WS calves showing higher pain response scores than VS calves (OR = 4.08, 95% CI: 1.34–12.42, p = 0.011). Ear notching resulted in greater pain response scores than ear tagging (OR = 23.19, 95% CI: 6.18–87.05, p < 0.001).

Conclusions

and clinical relevance Vapocoolant spray induced local anaesthesia and significantly reduced the pain response to ear tagging and ear notching in calves. Ear notching is more painful than ear tagging. Cryoanaesthesia is an effective option for reducing the perioperative pain associated with these simple husbandry procedures.  相似文献   

17.

Objective

Variants in the MC1R gene have been associated with red hair color and sensitivity to pain in humans. The study objective was to determine if a relationship exists between MC1R genotype and physiological thermal or mechanical nociceptive thresholds in Labrador Retriever dogs.

Study design

Prospective experimental study.

Animals

Thirty-four Labrador Retriever dogs were included in the study following public requests for volunteers. Owner consent was obtained and owners verified that their dog was apparently not experiencing pain and had not been treated for pain during the previous 14 days. The study was approved by the Institutional Animal Care and Use Committee.

Methods

Nociceptive thresholds were determined from a mean of three thermal and five mechanical replications using commercially available algometers. Each dog was genotyped for the previously described MC1R variant (R306ter). Data were analyzed using one-way anova with post hoc comparisons using Tukey’s test (p < 0.05).

Results

Thirteen dogs were homozygous wild-type (WT/WT), nine were heterozygous (WT/R306ter), and eight were homozygous variant (R306ter/R306ter) genotype. Four dogs could not be genotyped. A significant difference (p = 0.04) in mechanical nociceptive thresholds was identified between dogs with the WT/WT genotype (12.1 ± 2.1 N) and those with the WT/R306ter genotype (9.2 ± 2.4 N).

Conclusion

A difference in mechanical, but not thermal, nociceptive threshold was observed between wild-type and heterozygous MC1R variants. Differences in nociceptive thresholds between homozygous R306ter variants and other genotypes for MC1R were not observed.

Clinical relevance

Compared with the wild-type MC1R genotype, nociceptive sensitivity to mechanical force in dogs with a single variant R306ter allele may be greater. However, in contrast to the reported association between homozygous MC1R variants (associated with red hair color) and nociception in humans, we found no evidence of a similar relationship in dogs with the homozygous variant genotype.  相似文献   

18.

Objective

To investigate the expression and distribution of desmosomal and gap junction proteins of the intercalated disc in the atria of boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC).

Animals

Nineteen control dogs and 13 boxers with histopathologically confirmed ARVC.

Methods

Right and left atrial samples were examined using immunofluorescence and Western blots. The intercalated disc proteins investigated included total and phosphorylated connexin43 (Cx43 and pCx43), connexin45, connexin40, plakoglobin, plakophilin-2, desmoplakin, and N-cadherin.

Results

Histopathological changes characteristic of ARVC were present in the left or right atrium of 12 out of 13 boxers and were absent in all control dogs. When compared to the 19 control dogs, immunofluorescence analysis revealed a decrease in signal intensity for pCx43 and plakoglobin in the left (p = 0.03 and p = 0.014, respectively) and right atrium (p = 0.015 and p = 0.002, respectively) of affected boxers. Connexin43 and pCx43 Western blot band density was significantly decreased in the left (p = 0.025 and p = 0.027, respectively) and right atrium (p = 0.001 and p = 0.044, respectively) of affected boxers.

Conclusion

Altered intercalated disc and gap junction proteins were identified in atrial myocardium of ARVC boxers, supporting atrial involvement as part of this disorder. Reduction in pCx43 in conjunction with histological changes could represent the substrate for atrial arrhythmias associated with ARVC. Furthermore, these findings detected in boxer dogs, lend support for the broader term, arrhythmogenic cardiomyopathy, as preferred nomenclature used to describe this disease in humans.  相似文献   

19.

Objective

To evaluate the ability of a noninvasive cardiac output monitoring system with electrical velocimetry (EV) for predicting fluid responsiveness in dogs undergoing cardiac surgery.

Study design

Prospective experimental trial.

Animals

A total of 30 adult Beagle dogs.

Methods

Stroke volume (SV), stroke volume variation (SVV) and cardiac index were measured using the EV device in sevoflurane-anaesthetized, mechanically ventilated dogs undergoing thoracotomies for experimental creation of right ventricular failure. The dogs were considered fluid responsive if stroke volume (SVI; indexed to body weight), measured using pulmonary artery thermodilution, increased by 10% or more after volume loading (10 mL kg–1). Relationships of SVV, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) with SVI were analysed to estimate fluid responsiveness.

Results

Better prediction of fluid responsiveness, with a significant area under the receiver operating characteristic curve, was observed for SVV (0.85 ± 0.07; p = 0.0016) in comparison with CVP (0.65 ± 0.11; p = 0.17) or PAOP (0.60 ± 0.12; p = 0.35), with a cut-off value of 13.5% (84% specificity and 73% sensitivity).

Conclusions and clinical relevance

SVV derived from EV is useful for identification of dogs that are likely to respond to fluids, providing valuable information on volume status under cardiothoracic anaesthesia.  相似文献   

20.

Objective

To compare the effectiveness of ultrasound- and electrostimulation-guided nerve blocks of the brachial plexus and to determine whether ultrasound guidance is feasible in conscious dogs.

Study design

Blinded, crossover, experimental study.

Animals

Six clinically healthy adult Beagle dogs.

Methods

The nerves of the brachial plexus of the right thoracic limb were blocked under ultrasound guidance (UNB) in conscious dogs and under electrostimulation guidance (ENB) in anesthetized dogs with bupivacaine (0.4 mL kg–1, 0.25%). Saline (0.4 mL kg–1) was injected in control animals. Sensory nerve blockade was evaluated by scoring cutaneous sensation in targeted nerves. Motor nerve blockade was evaluated based on weight bearing, conscious proprioception and withdrawal reflex scores. Times to execute the technique in UNB and ENB were compared using t tests (p < 0.05). Scores for sensory and motor nerve blockades in each treatment were compared with scores before treatment and with control treatment scores using nonparametric repeated-measures two-way analysis of variance. Time to onset and duration of sensory nerve block were assessed using scores for four sensory nerve functions. A successful sensory nerve block was defined by decreases in scores for these functions. Success rates of nerve blocks were compared among treatments using McNemar’s test.

Results

In UNB and ENB, onset times of sensory nerve blocks were 1 hour and 1.5 hours, respectively. Onset times of motor nerve blocks were 0.5 hour in both treatments. In UNB and ENB, durations of sensory nerve block were 3 hours and 0.5 hour, respectively, and durations of motor nerve block were 7.5 hours and 6.5 hours, respectively. Success rates did not differ between the techniques.

Conclusions and clinical relevance

The UNB brachial plexus block had a shorter onset time and longer duration than ENB. UNB can be performed in conscious dogs or those under mild sedation.  相似文献   

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