Effect of clomipramine on the electrocardiogram and serum thyroid concentrations of healthy cats

Clomipramine is a tricyclic antidepressant (TCA) commonly used to treat anxiety related behavioral disorders in companion animals. Tricyclic antidepressants (TCAs) have the potential to cause arrhythmias in humans and companion animals. The effect of the TCAs, clomipramine, and amitriptyline, at therapeutic dosages on cardiac rhythm has been evaluated in dogs. The effect of clomipramine on the cardiac rhythm of cats has not been reported. In Experiment 1, 7 healthy cats were selected to evaluate the effect of clomipramine on their cardiac rhythm using an electrocardiogram. A baseline electrocardiogram was carried out before (Day 0) and repeated (Day 29) after 4 weeks (28 days) of daily clomipramine (10 mg/cat PO) administration. Significant changes in the electrocardiogram were not found after 28 days of daily clomipramine administration. In Experiment 2, 7 healthy cats were enrolled in the study to evaluate the effect of clomipramine administration on the serum thyroid concentrations in cats. Clomipramine (10 mg/cat PO daily) was administered to all cats beginning on Day 1, and continued for 28 days. Serum total thyroxine (T₄), triiodothyronine (T₃), and free thyroxine (fT₄) concentrations were measured before (Day 0) and repeated (Day 29) after 4 weeks (28 days) of daily clomipramine administration. Statistically significant decreases in serum thyroid concentrations (T_4, T₃, and fT₄) were noted between pre and post clomipramine administration. A decrease of 25, 24, and 16% in serum T₄, T₃, and fT₄ concentrations, respectively, may lead to a misdiagnosis of euthyroidism in a subclinical hyperthyroid patient. A longer duration of drug treatment might further suppress thyroid function when used as a single agent, with concomitantly administered drugs, or in conjunction with euthyroid sick syndrome.     

Changes of Circulating Total and Free Iodothyronine in Horses After Competitive Show Jumping With Different Fence Height

The effect of exercise on circulating T₃, T_4, free (f) T₃, and fT₄ concentrations were studied before and after competitive show jumping in 24 trained jumper horses with an age range of 11–13 years and having the same level of show experience. All horses, randomly divided into three groups paired by gender, participated in three competition levels with the same circuit design over 10 fences, with five upright and five cross-pole fences .The three fence height groups were group I (n = 8), 1.10 m; group II (n = 8), 1.20 m; and group III (n = 8), 1.30 m. Repeated measures analysis of variance showed a statistically significant effect of competitive exercise on fT₃ changes in all groups, whereas the effect of competitive exercise on T₃ changes was exclusively seen in group III. Two-way repeated measures analysis of variance showed that the effect of fence height (P = .0002) and performance results were significant (P = .0486) only for T₃ changes. Performance also affected fT₃ changes (P = .0152). No significant correlation was found between total and free iodothyronines. These results suggest a dependence of T₃ and fT₃ changes on exercise-related variables and performance results and that the thyroid response is different with respect to the different exercise-related variables, such as the varying level of difficulty and performance results.     

Effect of Long-distance Road Transport on Thyroid and Adrenal Function and Haematocrit Values in Limousin Cattle: Influence of Body Weight Decrease

The purpose of this study was to evaluate the effect of long-distance road transport as a relevant stressor on total and free iodothyronines, cortisol levels and haematocrit values in 10 male Limousin cattle. Serum T₃,T₄,fT₃,fT₄ and cortisol concentrations were analysed by immunoenzymatic assays. Serum cortisol levels and haematocrit modifications were also evaluated on the basis of percentage body weight decrease. The results showed a general increase of total and free iodothyronines and cortisol levels after short-and long-distance road transport and a decrease 15 days after transport, as compared to basal values. Significant positive correlations between T₃ and T₄, between T₃ and fT₃, and between T₄ and fT₄ were found. These results suggest that transport stress induces an increase in the activity of thyroid and adrenal function in Limousin cattle that is evident after even a short-distance road transport and continues to increase after long-distance transport.     

Circadian variations of serum thyroxine, free thyroxine and 3,5,3'triiodothyronine concentrations in healthy dogs

This study was to determine the daily fluctuation of serum thyroxine (tT₄), free thyroxine (fT₄), 3,5,3''-triiodothyronine (T₃) concentrations in healthy dogs. Thyroid function of these dogs was evaluated on the basis of results of TSH response test. Samples for the measurement of serum tT₄, fT₄, and T₃ concentrations were obtained at 3-hour intervals from 8 : 00 to 20 : 00. Serum tT₄, fT₄, and T₃ concentrations were measured by the enzyme chemiluminescent immunoassay (ECLIA). Mean T₃ concentrations had no significant differences according to the sample collection time during the day. Mean tT₄ and fT₄ concentrations at 11 : 00 were 3.28 ± 0.86 µg/dl and 1.30 ± 0.37 ng/dl, respectively and mean tT₄ and fT₄ at 14:00 were 3.54 ± 1.15 µg/dl and 1.35 ± 0.12 ng/dl, respectively. These concentrations were significantly high compared with tT₄ and fT₄ concentrations at 8:00, which were 1.75 ± 0.75 µg/dl and 0.97 ± 0.25 ng/dl, respectively (p < 0.05). According to the sample collection time, mean tT₄ and fT₄ concentrations changed with similar fluctuation during the day. Based on these results, it was considered that measurement of serum tT₄ and fT₄ concentrations from 11 : 00 to 14 : 00 might more easily diagnose the canine hypothyroidism in practice.     

The effects of ketamine‐midazolam anesthesia on intraocular pressure in clinically normal dogs

Objective To determine the effects of intravenous ketamine‐midazolam anesthesia on intraocular pressure (IOP) in ocular normotensive dogs. Animals Thirteen adult mixed‐breed dogs. Procedures Dogs were randomly assigned to treatment (n = 7) and control (n = 6) groups. Dogs in the treatment group received intravenous ketamine 15 mg/kg and midazolam 0.2 mg/kg and dogs in the control group received intravenous saline. The time of intravenous drug injection was recorded (T₀). Measurements of IOP were then repeated 5 min (T₅) and 20 min (T₂₀) following the intravenous administration of ketamine‐midazolam combination and saline in both groups. Results Measurements showed normal IOP values in both groups. The mean ± SD baseline IOP values for treatment and control groups were 13.00 ± 1.47 and 10.33 ± 2.20, respectively. For baseline IOP values, there was no significant difference between treatment and control groups (P = 0.162). In the treatment group, the subsequent post‐treatment mean ± SD values were 15.64 ± 2.17 (5 min), and 14.92 ± 1.98 (20 min). There was no evidence of statistical difference between baseline values and post‐treatment values after treatment with ketamine‐midazolam (P₅ = 0.139; P₂₀ = 0.442). In control eyes, the mean ± SD values at 5 and 20 min were 10.41 ± 2.01 and 10.16 ± 1.69, respectively. There was no significant difference between baseline values and post‐treatment values in control group (P₅ = 1.000; P₂₀ = 1.000). Conclusion Ketamine‐midazolam combination has no clinically significant effect on IOP in the dog.     

Assessment of cardiac troponin I and C-reactive protein concentrations associated with anesthetic protocols using sevoflurane or a combination of fentanyl, midazolam, and sevoflurane in dogs

ObjectiveTo report serum cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs anesthetized for elective surgery using two anesthetic protocols.Study designProspective, randomized clinical study.AnimalsTwenty client-owned dogs presenting for elective ovariohysterectomy or castration.MethodsThe dogs were randomized into two groups. All dogs were premedicated with glycopyrrolate (0.011 mg kg^?1) and hydromorphone (0.1 mg kg^?1) IM approximately 30 minutes prior to induction of anesthesia. Anesthesia in dogs in group 1 was induced with propofol (6 mg kg^?1) IV to effect and in dogs in group 2 with diazepam (0.2 mg kg^?1) IV followed by etomidate (2 mg kg^?1) IV to effect. For maintenance of anesthesia, group 1 received sevoflurane (adjustable vaporizer setting 0.5–4%) and group 2 received a combination of fentanyl (0.8 μg kg^?1 minute^?1) and midazolam (8.0 μg kg^?1 minute^?1) IV plus sevoflurane (adjustable vaporizer setting 0.5–4%) to maintain anesthesia. Serum cTnI and CRP concentrations were measured at baseline and 6, 18, and 24 hours post-anesthetic induction. Biochemical analysis was performed at baseline. Lactate was obtained at baseline and 6 hours post-anesthetic induction. Heart rate and mean arterial blood pressure were measured intra-operatively.ResultsBaseline serum cTnI and CRP concentrations were comparable between groups. A significant difference in serum cTnI or CRP concentrations was not detected post-operatively between groups at any time point. Serum CRP concentrations were significantly increased post-anesthetic induction in both groups, which was attributed to surgical trauma.Conclusions and clinical relevanceThere was no significant difference in serum cTnI and CRP concentrations between anesthetic protocols. Further investigation in a larger number of dogs is necessary to confirm the current findings.     

Continuous infusion of ketamine in hypovolemic dogs anesthetized with desflurane

Objective: To evaluate the cardiorespiratory effects of continuous infusion of ketamine in hypovolemic dogs anesthetized with desflurane. Design: A prospective experimental study. Animals: Twelve mixed breed dogs allocated into 2 groups: saline (n=6) and ketamine (n=6). Interventions: After obtaining baseline measurements (time [T] 0) in awake dogs, hypovolemia was induced by the removal of 40 mL of blood/kg over 30 minutes. Anesthesia was induced and maintained with desflurane (1.5 minimal alveolar concentration) and 30 minutes later (T75) a continuous intravenous (IV) infusion of saline or ketamine (100 μg/kg/min) was initiated. Cardiorespiratory evaluations were obtained 15 minutes after hemorrhage (T45), 30 minutes after desflurane anesthesia, and immediately before initiating the infusion (T75), and 5 (T80), 15 (T90), 30 (T105) and 45 (T120) minutes after beginning the infusion. Measurements and main results: Hypovolemia (T45) reduced the arterial blood pressures (systolic arterial pressure, diastolic arterial pressure [DAP] and mean arterial pressure [MAP]), cardiac (CI) and systolic (SI) indexes, and mean pulmonary arterial pressure (PAP) in both groups. After 30 minutes of desflurane anesthesia (T75), an additional decrease of MAP in both groups was observed, heart rate was higher than T0 at T75, T80, T90 and T105 in saline‐treated dogs only, and the CI was higher in the ketamine group than in the saline group at T75. Five minutes after starting the infusion (T80), respiratory rate (RR) was lower and the end‐tidal CO₂ (ETCO₂) was higher compared with values at T45 in ketamine‐treated dogs. Mean values of ETCO₂ were higher in ketamine than in saline dogs between T75 and T120. The systemic vascular resistance index (SVRI) was decreased between T80 and T120 in ketamine when compared with T45. Conclusions: Continuous IV infusion of ketamine in hypovolemic dogs anesthetized with desflurane induced an increase in ETCO₂, but other cardiorespiratory alterations did not differ from those observed when the same concentration of desflurane was used as the sole anesthetic agent. However, this study did not evaluate the effectiveness of ketamine infusion in reducing desflurane dose requirements in hypovolemic dogs or the cardiorespiratory effects of ketamine–desflurane balanced anesthesia.     

EVALUATION OF QUANTITATIVE THYROID SCINTIGRAPHY FOR DIAGNOSIS AND STAGING OF DISEASE SEVERITY IN CATS WITH HYPERTHYROIDISM: COMPARISON OF THE PERCENT THYROIDAL UPTAKE OF PERTECHNETATE TO THYROID‐TO‐SALIVARY RATIO AND THYROID‐TO‐BACKGROUND RATIOS

Thyroid scintigraphy is commonly used for evaluation of cats with hyperthyroidism, with the thyroid‐to‐salivary ratio (T/S) being the most common method to quantify the degree of thyroid activity and disease. Calculation of thyroid‐to‐background ratios (T/B) or percent thyroidal uptake of ^99mTcO^?₄ (TcTU) has only been reported in a few studies. The purpose of this prospective, cross‐sectional study was to evaluate a number of quantitative scintigraphic indices as diagnostic tests for hyperthyroidism, including the T/S, three different T/B, TcTU, and estimated thyroid volume. Of 524 cats referred to our clinic for evaluation of suspected hyperthyroidism, the diagnosis was confirmed (n = 504) or excluded (n = 20) based on results of a serum thyroid panel consisting of thyroxine (T₄), triiodothyronine (T₃), free T₄ (fT₄), and thyroid‐stimulating hormone (TSH) concentrations. In the hyperthyroid cats, median values for TcTU, T/S, and three T/B ratios were all significantly higher (P < 0.001) than values in euthyroid suspect cats or clinically normal cats. All scintigraphic parameters were relatively sensitive and specific as diagnostic tests for hyperthyroidism, but the T/S ratio had the highest test accuracy. The T/S ratio correlated strongly with the TcTU (r = 0.85). However, the TcTU had a higher and more significant correlation (P < 0.01) with serum T₄ (r = 0.76 vs. 0.64), T₃ (r = 0.77 vs. 0.64), and estimated thyroid volume (r = 0.62 vs. 0.38). Overall, calculation of TcTU is an accurate diagnostic test, but also appears to be the best parameter to predict the functional volume and metabolic activity of the feline adenomatous thyroid gland.     

Lithium dilution cardiac output and oxygen delivery in conscious dogs with systemic inflammatory response syndrome

Objective: Compare cardiac index (CI) and oxygen delivery index (DO₂I) in conscious, critically ill dogs to control dogs; evaluate the association of CI and DO₂I with outcome. Design: Prospective non‐randomized clinical study. Setting: Veterinary teaching hospital. Animals: Eighteen client‐owned dogs with systemic inflammatory response syndrome (SIRS) and 8 healthy control dogs. Measurements and Main Results: CI of dogs with SIRS was measured using lithium dilution at times 0, 4, 8, 16, and 24 hours. Data collected included physical exam, arterial blood gas (ABG) and hemoximetry. CI of control dogs was measured 3 times with 1 measurement of ABG. Mean CI ± SE in SIRS patients was 3.32 ± 0.95 L/min/m²; lower than controls at 4.18 ± 0.22 L/min/m² (P<0.001). Mean DO₂I ± SE in SIRS patients was 412.91 ± 156.67 mL O₂/min/m²; lower than controls at 785.24 ± 45.99 mL O₂/min/m² (P<0.001). There was no difference in CI (P=0.49) or DO₂I (P=0.51) for dogs that survived to discharge versus those that did not. There was no difference in mean CI (P=0.97) or DO₂I (P=0.50) of survivors versus non‐survivors for 28‐day survival. Survivors had lower blood glucose (P=0.03) and serum lactate concentrations (P=0.04) than non‐survivors. Conclusions: CI and DO₂I in conscious dogs with SIRS were lower than control dogs, which differs from theories that dogs with SIRS are in a high cardiac output state. CI and DO₂I were not significantly different between survivors and non‐survivors. Similar to previous studies, lactate and glucose concentrations of survivors were lower than non‐survivors.     

The effect of a single dose of topical 0.005% latanoprost and 2% dorzolamide/0.5% timolol combination on the blood-aqueous barrier in dogs: a pilot study

Objective To determine the effects of 0.005% latanoprost and 2% dorzolamide/0.5% timolol on the blood‐aqueous barrier (BAB) in normal dogs. Animals studied Eight mixed‐breed and pure‐breed dogs. Procedures Baseline anterior chamber fluorophotometry was performed on eight normal dogs. Sodium fluorescein was injected and the dogs were scanned 60–90 min post‐injection. Seventy‐two hours following the baseline scan, one eye received one drop of latanoprost. Fluorophotometry was repeated 4 h after drug administration. Following a washout period, the identical procedure was performed 4 h after the administration of dorzolamide/timolol. The degree of BAB breakdown was determined by comparing the concentrations of fluorescein within the anterior chamber before and after drug administration. BAB breakdown was expressed as a percentage increase in the post‐treatment fluorescein concentration over the baseline concentration: %INC [Fl] = {([Fl]_post – [Fl]_baseline)/[Fl]_baseline} × 100. The percentage increase in fluorescein concentration in the treated eye was compared to that in the nontreated eye using a paired t‐test with significance set at P ≤ 0.05. Results Following administration of latanoprost, the fluorescein in the treated eyes increased 49% (± 58%) from baseline compared to 10% (± 31%) in the untreated eyes (P = 0.016). Following administration of dorzolamide/timolol, the fluorescein concentration increased 38% (± 54%) compared to baseline vs. 24% (± 38%) in the untreated eyes (P = 0.22). Conclusions The results of this study show that topical latanoprost may cause BAB disruption in normal dogs while topical dorzolamide/timolol may have no effect on the BAB in normal dogs.     

Endotoxn-induced nonthyroidal illness in dogs

OBJECTIVE: To determine the effects of endotoxin administration on thyroid function test results and serum tumor necrosis factor-alpha (TNF-alpha) activity in healthy dogs. ANIMALS: 6 healthy adult male dogs. PROCEDURES: Serum concentrations of thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3'5'-triiodothyronine (rT3), free T4 (fT4), and endogenous canine thyroid stimulating hormone (TSH), and TNF-alpha activity were measured before (day-1; baseline), during (days 0 to 3), and after (days 4 to 24) IV administration of endotoxin every 12 hours for 84 hours. RESULTS: Compared with baseline values, serum T3 concentration decreased significantly, whereas rT3 concentration increased significantly 8 hours after initial endotoxin administration. Serum T4 concentration decreased significantly at 8 and 12 hours after initiating endotoxin administration. Serum T4 concentration returned to reference range limits, then decreased significantly on days 6 to 12 and 16 to 20. Serum fT4 concentration increased significantly at 12, 24, and 48 hours after cessation of endotoxin treatment, compared with baseline values. Serum rT3 concentration returned to reference range, then decreased significantly days 5 and 7 after stopping endotoxin treatment. Serum TNF-alpha activity was significantly increased only 4 hours after initial endotoxin treatment, compared with baseline activity. CONCLUSIONS AND CLINICAL RELEVANCE: Endotoxin administration modeled alterations in thyroid function test results found in dogs with spontaneous nonthyroidal illness syndrome. A decrease in serum T4 andT3 concentrations and increase in serum rT3 concentration indicate impaired secretion and metabolism of thyroid hormones. The persistent decrease in serum T4 concentration indicates that caution should be used in interpreting serum T4 concentrations after resolution of an illness in dogs.     

Myoglobin as a prognostic indicator for outcome in dogs with gastric dilatation-volvulus

Objective – To determine whether myoglobin (Mb) is a useful prognostic indicator for outcome and to investigate any relationship between Mb and mortality in dogs with gastric dilatation‐volvulus (GDV). Design – Prospective study. Setting – Veterinary teaching hospital. Animals – Seventy‐two dogs with GDV. Interventions – Blood sampling. Measurements and Main Results – Mb levels were measured at the time of diagnosis (Mbt₀), 24 hours (Mbt₁), and 48 hours (Mbt₂) after signs of GDV were recognized. Fifty‐seven dogs survived (group I) and 15 dogs did not survive (group II). Mb t₀ differed significantly between groups (P=0.04). Mbt₀ in group I ranged from <30 to >700 ng/mL (n=57, median 74 ng/mL), and in group II from 34 to >700 ng/mL (n=15, median 238 ng/mL). Analysis of a receiver operating characteristic curve of Mbt₀ suggested that the best single cutpoint would be 168 ng/mL (sensitivity 60.0%, specificity 84.2%). Fifty percent of dogs with Mbt₀>168 ng/mL were euthanized, while 88.9% with Mbt₀<168 ng/mL survived. Mbt₁ and Mbt₂ differed significantly between groups I and II. Mbt₁ in group I ranged from 32 to >700 ng/mL (n=55, median 123 ng/mL), and Mbt₁ in group II ranged from 131 to 643 ng/mL (n=7, median 343 ng/mL) (P=0.006). Mbt₂ in group I ranged from 30 to 597 ng/mL (n=54, median 101 ng/mL), and in group II from 141 to >700 ng/mL (n=8, median 203 ng/mL) (P=0.02). Conclusions – In this study, Mbt₀ is a moderately sensitive and specific prognostic indicator. Almost 90% of the dogs below the cutpoint survived to discharge, whereas 50% with Mbt₀ above the cutpoint did not survive.     

Effect of thyrotropin releasing hormone (TRH) on serum levels of thyroid hormones in thoroughbred mares

Effects of thyrotropin releasing hormone (TRH) on serum levels of thyroid hormones were studied in 12 Thoroughbred mares. Significant increases (P<0.05) of serum T4 levels occurred as early as 2 hours and peaked at 4–10 hours after intravenous injection of 0.5 – 5 mg TRH. Following injection of 0.5, 1, 3 and 5 mg of TRH the serum levels of T4 were increased 2.25, 2.42,2.42 and 3.67 fold, respectively, over pre-injection levels. Serum levels of T3 were also significantly increased (P<0.05) at 1 or 2 hours and peaked at 2 to 4 hoursafter injection. The mean peak increase of T₃ levels were 2.87, 3.21, 3.10 and 3.10 fold over pre- injected in level in 0.5, 1, 3,5 mg treated horses, respectively. These results suggest that TRH can be an alternative to heterologous TSH for the equine thyroid function test. The recommended dosage is 1–3 mg, and most appropriate time to collect post-TRH blood sample is between 4–6 hours. Serum levels of T₄ and T₃ should increase 2–3 fold from baseline in normal horses.     

S100B protein and neuron-specific enolase as predictors of postoperative cognitive dysfunction in aged dogs: a case-control study

ObjectivePostoperative cognitive dysfunction (POCD) may be related to brain injury. S100B protein and neuron-specific enolase (NSE) have been investigated as potential biochemical markers of neural cell injury in animals and humans. This study aimed to investigate the association between POCD, brain injury and serum concentrations of S100B and NSE after periodontal surgery in aged dogs.Study designProspective observational animal study.AnimalsA total of 24 male and female dogs undergoing periodontal surgery.MethodsDogs were separated into two groups based on age: control group, 10 dogs ≤ 8 years and aged group, 14 dogs > 8 years. Cognitive function was measured preoperatively and on the seventh postoperative day using the Canine Cognitive Dysfunction Rating scale and the Age-Related Cognitive and Affective Disorders scale. S100B protein and NSE serum concentrations were measured before and immediately after the surgery.ResultsPOCD was not observed after surgery in the present study. Serum concentrations of S100B and NSE were increased postoperatively in the control group but not in the aged group (p = 0.04 and 0.03, respectively). Preoperative S100B serum concentrations were significantly higher in the aged group (p = 0.01).ConclusionsThere was no association between POCD and high concentrations of S100B and NSE in dogs. However, increased postoperative serum concentrations of S100B and NSE were found in the control group after surgery, an effect that may indicate neural damage.Clinical relevanceThe results suggest that anesthesia and oral surgery are associated with higher postoperative serum concentrations of S100B and NSE in dogs ≤ 8 years old, which may indicate neural damage. Serum concentrations of S100B were elevated in aged dogs before anesthesia, a finding that might be related to chronic preoperative brain damage.     

The Effect of Epidural and General Anesthesia on the Healing of Colonic Anastomoses

Colonic anastomoses were performed on two groups of 13 dogs each. Epidural anesthesia and general anesthesia were performed in one group and general anesthesia only in the other. Intraoperatively, the epidural-general anesthesia dogs tended to bleed less, making the anastomosis less difficult. Histologic comparisons showed healing to be more advanced in the epidural-general anesthesia dogs compared to the general anesthesia dogs 24 hours and 7 days postoperatively. Differences were not noticed 14 and 28 days postoperatively. Bursting pressures were determined 24 hours after surgery. Differences between the groups were not noticed. Leakage occurred at 72% of the pressure determined to cause leakage in normal colons.     

Sedative effects and serum concentrations across time after subcutaneous administration of liposome-encapsulated or standard oxymorphone in healthy dogs

Our lab has developed a slow‐release liposomal formulation of oxymorphone (LEOx). The purpose of this study was to compare sedative effects and serum concentrations of oxymorphone after administration of LEOx and standard oxymorphone (STDOx) to dogs. At baseline, 1 mL of blood was drawn from the cephalic vein and sedation score was recorded. Dogs were divided into four groups (n = 6): (i) LEOx 1.0 mg kg^–1; (ii) LEOx 0.5 mg kg^–1; (iii) STDOx 0.1 mg kg^–1; (iv) STDOx 0.05 mg kg^–1. Unloaded liposomal vehicle (0.5 mL) was used as a control (n = 2). All treatments were given subcutaneously between the scapulae. Sedation score and serum concentration of drug were recorded at 0.5, 1, 2, 4, 8, 12, 16, 24 hours and daily for 5 days. Serum concentrations were measured with ELISA. At all time points, drug was not detected and sedation score was 0 in the control group. Sedation score for group 1 was significantly higher (p < 0.05) at 1 hour than for groups 2,3, and 4. There was no difference in sedation score between treatment groups at any other time. Serum concentrations of drug were significantly higher (p < 0.05) for group 1 at all time points measured after baseline. In groups 2, 3, and 4, serum concentrations of drug fell below the limit of detection (1.5 ng mL^–1) by 24 hours. Serum concentrations after 0.1 mg kg^–1of STDOx were 11.1 ± 3.6 ng mL^–1at 4 hours, which is the recommended time for redosing and presumably reflects the lower end of a therapeutic serum concentration. Serum concentrations were comparable after 1.0 mg kg^–1 of LEOx (10.5 ± 2.4 ng mL^–1) 48 hours after administration. These results suggest that liposomal oxymorphone may provide therapeutic serum concentrations of drug for 2 days after a single subcutaneous administration without undue sedation or other deleterious effects in healthy dogs. Further studies are warranted to assess analgesic efficacy and pharmacokinetics of lipsomal oxymorphone in dogs.     

SHORT‐TERM EFFECT OF RECOMBINANT HUMAN THYROID‐STIMULATING HORMONE ON THYROID VOLUME AND ECHOGENICITY IN HEALTHY BEAGLES

In humans, administration of recombinant human thyroid stimulating hormone (rhTSH) allows radioactive iodine dose reduction and higher efficacy in the treatment of multinodular goiter and thyroid cancer. A similar effect might be expected in dogs with thyroid carcinoma. However, if rhTSH leads to an increase in thyroid volume, it must be used carefully in dogs with large thyroid tumors to avoid compression of key anatomical structures. The aim of this study was to determine the short‐term effect of rhTSH on thyroid volume and echogenicity, measured by ultrasonography, in healthy Beagles. Seven beagles were divided randomly in two groups in a prospective placebo‐controlled blinded cross‐over study. On day 1, one group received 100 μg of rhTSH intravenously and the other group received placebo. After a wash‐out period of 3 weeks, the groups were crossed over. Evaluation of thyroid echogenicity, homogeneity, shape, capsule delineation, and measurement of thyroid length, width, and height were performed by the same observer at baseline, and at 6, 24, and 48 h after injection of rhTSH and placebo. There was no significant difference between the effect of rhTSH and placebo on thyroid volume (P=0.397), echogenicity, homogeneity, or capsule delineation. Time had a significant effect on thyroid volume (P=0.027). No adverse effects after rhTSH administration were noticed. The effect of rhTSH on thyroid volume in dogs with thyroid carcinoma needs to be assessed.     

Serial determination of biomarkers of oxidative stress and antioxidant status in dogs with naturally occurring gastric dilatation-volvulus

Objective: To serially determine the biomarkers of oxidative stress and antioxidant status of dogs with gastric dilatation‐volvulus (GDV) over 48 hours. Design: Prospective study. Setting: Veterinary teaching hospital intensive care unit. Animals: Thirteen client‐owned dogs with GDV. Interventions: None. Measurement and main results: For all dogs, biomarkers of oxidative stress and antioxidant status were ascertained. Indicators of oxidative stress measured included F_2α‐isoprostanes (isoprostanes) and malondialdehyde (MDA). Vitamin C, vitamin E, glutathione peroxidase (GSHPx), and oxygen radical absorbance capacity (ORAC) were measured to assess antioxidant status. Oxidants and antioxidants were measured at the time of admission and at 24 and 48 hours post‐admission. There were significant decreases in vitamin E (P=0.002), vitamin C (P=0.001), ORAC (P=0.02), and MDA (P=0.001) during hospitalization. There was no significant change in GSHPx and isoprostane concentrations over time. Conclusion: Oxidative stress and antioxidant capacity in dogs with GDV change over time. Further studies measuring oxidative stress in more severely affected dogs and performing measurements earlier in the disease process may be beneficial in determining when oxidative stress is most severe during the course of GDV management.     

Analgesic effect of pre-operative etodolac and butorphanol administration in dogs undergoing ovariohysterectomy

The analgesic, bleeding, and renal effects of dogs pre‐medicated with etodolac with and without butorphanol were evaluated. Twenty‐four 1‐year‐old healthy dogs, weighing 19 ± 3 kg (mean ± SD) were randomly assigned to four treatment groups (n = 6): control (C), etodolac (E), butorphanol (B), and etodolac with butorphanol (EB). Etodolac (12–14 mg kg^?1 PO) was given 1 hour before propofol induction and isoflurane maintenance anesthesia. Butorphanol (0.4 mg kg^?1 IV) was given immediately following endotracheal intubation. Control dogs received only propofol (8 mg kg^?1 to effect) and isoflurane anesthesia. All dogs were mechanically ventilated to maintain Pe ′CO₂ between 35 and 45 mm Hg (4.7–6.0 kPa). Lactated Ringer's solution was given at 10 mL kg^?1 hour^?1 during anesthesia. Plasma cortisol concentrations were assessed 1 day prior to surgery (baseline), immediately prior to anesthesia induction, and every 30 minutes until 5 hours following extubation, and 1 day after surgery. Total duration of anesthesia was 50 minutes and total surgery duration was 30 minutes. Isoflurane concentration area under the curve (AUC) over time during the anesthesia was compared among treatment groups. Buccal mucosal bleeding time (BMBT) was assessed 1 day before E administration and during surgery. Urine GGT to urine creatinine ratio, BUN, and plasma creatinine were taken daily from 1 day before to 3 days after surgery. Behavioral pain scores (numerical rating scale) were assessed by two observers blinded to the treatment during the 5‐hour recovery period at 30 minute intervals until 3 hours, and again at 5 hours after extubation. All data were analyzed using anova . Multiple comparisons were performed if the anova was significant. Alpha value was set at 0.05. Plasma cortisol concentrations significantly increased from time of extubation in all the treatment groups. They did not return to the baseline until 5, 2.5, 1.5, and 1.5 hours after extubation in the C, B, E, and EB groups, respectively. Isoflurane AUC was not significantly different among treatment groups. Dogs treated with EB had significantly less behavioral pain than all other groups throughout the 5‐hour recovery period. No significant difference was found between treatment groups or within treatment groups over time in BMBT, or any renal variables. This study demonstrated that (i) pre‐operative administration of E provides profound analgesia during the post‐operative period without renal or bleeding side‐effects in dogs undergoing OHE; and (ii) a combination of butorphanol–etodolac provides the best analgesic effect during the post‐operative period based on the behavioral pain score.     

Effect of administration of nonsteroidal anti-inflammatory drugs before surgery on renal function in clinically normal dogs

OBJECTIVES: To investigate renal function in clinically normal dogs undergoing general anesthesia for ovariohysterectomies that received nonsteriodal antiinflammatory drugs (NSAID) before surgery. ANIMALS: 40 clinically normal dogs. PROCEDURE: After induction of anesthesia, dogs were given an analgesic. Renal function was assessed before surgery and 24 and 48 hours after surgery by means of serum urea and creatinine concentrations, fractional clearance of sodium (FC(Na)), urine gamma-glutamyltransferase (GGT) and alkaline phosphatase (ALP) activities, and urine analysis. Ten dogs in each of 4 groups received ketorolac tromethamine (0.5 mg/kg of body weight), ketoprofen (1 mg/kg), carprofen (4 mg/kg), or morphine (0.1 mg/kg; control group). RESULTS: Duration of general anesthesia ranged from 1.75 to 5 hours, with a mean of 3 hours. Two ketorolac- and 2 ketoprofen-treated dogs had transient azotemia. A significant decrease in the FC(Na) between before surgery and 24 hours after surgery, and between before surgery and 48 hours after surgery, was found in ketoprofen- and carprofen-treated dogs. Ketorolac-, ketoprofen-, and morphine-treated dogs had a decrease in urine specific gravity. Two ketorolac, 1 ketoprofen-, 1 carprofen-, and 4 morphine-treated dogs had increases in renal tubular epithelial cells on urine sediment examination 24 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: In clinically normal dogs undergoing general anesthesia and elective surgery, the use of NSAID as analgesics is not contraindicated. Compared with ketorolac or ketoprofen, carprofen had the least effect on renal function and integrity.