Giselle Hosgood

Effects of dietary supplementation with fish oil on in vivo production of inflammatory mediators in clinically normal dogs

OBJECTIVE To evaluate the effect of diets enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on in vivo production of interleukin (IL)-1, IL-6, tumor necrosis factor (TNF)-alpha, prostaglandin E2 (PGE2), and platelet-activating factor (PAF) in dogs. ANIMALS 15 young healthy dogs. PROCEDURES Dogs were randomly allocated to receive an isocaloric ration supplemented with sunflower oil (n=5), fish oil (5), or fish oil plus vitamin E (5) for 12 weeks. At week 12, in vivo production of inflammatory mediators was evaluated in serum at multiple time points for 6 hours following stimulation with IV administration of lipopolysaccharide (LPS). RESULTS Serum activity or concentration (area under the curve) of IL-1, IL-6, and PGE2 significantly increased after LPS injection in all groups but to a lesser extent in dogs receiving the fish oil diet, compared with results for dogs receiving the sunflower oil diet. Serum activity of TNF-alpha and PAF concentration also increased significantly after LPS injection in all groups but did not differ significantly among groups. CONCLUSIONS AND CLINICAL RELEVANCE A fish oil-enriched diet consisting of 1.75 g of EPA/kg of diet and 2.2 g of DHA/kg of diet (dry-matter basis) with an n-6:n-3 fatty acid ratio of 3.4:1 was associated with significant reductions in serum PGE2 concentrations and IL-1 and IL-6 activities. Results supported the use of EPA- and DHA-enriched diets as part of antiinflammatory treatments for dogs with chronic inflammatory diseases. Additional studies in affected dogs are warranted to further evaluate beneficial anti-inflammatory effects of EPA- and DHA-enriched diets.

Transdermal methimazole treatment in cats with hyperthyroidism

The objectives of this study were to assess serum thyroxine concentrations and clinical response in hyperthyroid cats to treatment with transdermal methimazole, and to determine if further investigation is indicated. Clinical and laboratory data from 13 cats with hyperthyroidism were retrospectively evaluated. Methimazole (Tapazole, Eli Lilly) was formulated in a pleuronic lecithin organogel (PLO)-based vehicle and was applied to the inner pinna of the ear at a dosage ranging from 2.5 mg/cat q 24 h to 10.0 mg/cat q 12 h. During the treatment period, cats were re-evaluated at a mean of 4.3 weeks (recheck-1), and again at a mean of 5.4 months (recheck-2). Clinical improvement was observed, and significant decreases in thyroxine concentrations were measured at recheck-1 (mean: 39.57 nmol/L, SEM: 14.4, SD: 41.2) and recheck-2 (mean: 36.71 nmol/L, SEM: 13.9, SD: 45.56) compared to pretreatment concentrations (mean: 97.5 nmol/L, SEM: 11.42, SD: 39.5). No adverse effects were reported.

Perineal herniorrhaphy: perioperative data from 100 dogs

One hundred dogs (83 intact males, 15 castrated males, and two intact females) underwent 110 perineal herniorrhaphy procedures. Mixed-breed dogs (n = 32), miniature poodles (n = 14), Boston terriers (n = 11), and Pekingese (n = 9) were represented most frequently. Perineal swelling (n = 48) and a perineal defect on rectal palpation (n = 31) were common clinical signs. Twenty dogs had urinary bladder retroflexion and were significantly more likely to have elevated serum urea nitrogen and creatinine concentrations, hyperkalemia, hyperphosphatemia, and neutrophilic leukocytosis. Only five of 43 dogs evaluated radiographically had prostatomegaly. Of 30 dogs receiving oral barium, all had rectal deviation. The most frequent complications during the hospitalization period were incisional (n = 35), followed by rectal prolapse (n = 9), tenesmus (n = 8), and depression (n = 8). Fifty-six of 70 dogs with follow-up had no complications.

Effects of Long-Term Phenobarbital Treatment on the Liver in Dogs

Long‐term administration of phenobarbital has been reported to cause hepatic injury in dogs. Phenobarbital induces hepatic enzymes, and it may be difficult to distinguish the effect of enzyme induction on serum liver enzyme activities from actual hepatic damage. The hepatotoxicity of phenobarbital and the impact of enzyme induction on serum liver enzyme activity were investigated prospectively in 12 normal dogs. Phenobarbital was administered for 29 weeks at 5 mg per kilogram of body weight (range, 4.8— 6.6 mg/kg) PO q12h, resulting in therapeutic serum phenobarbital concentrations (20–40 μg/mL). Serum alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), γ‐glutamyltransferase (GGT), fasted bile acids (fBA), total bilirubin, and albumin were determined before and during treatment. Lateral abdominal radiographs, abdominal ultrasounds, and histopathologic examinations of liver tissue obtained by ultrasound‐guided biopsy were performed before and during treatment. Radiographs revealed a moderate increase in liver size in most dogs. Ultrasonographic examination revealed no change in liver echogenicity or architecture. No evidence of morphologic liver damage was observed histopathologically. ALP and ALT increased significantly (P < .05), GGT increased transiently, and albumin decreased transiently during the study. There were no significant changes in AST, bilirubin, and fBA. These results suggest that increases in serum ALP, ALT, and GGT may reflect enzyme induction rather than hepatic injury during phenobarbital treatment in dogs. Serum AST, fBA, and bilirubin, and ultrasonographic evaluation of the liver are not affected by the enzyme‐inducing effect of phenobarbital and can therefore be helpful to assess liver disease in dogs treated with the drug.

Cardiopulmonary, blood and peritoneal fluid alterations associated with abdominal insufflation of carbon dioxide in standing horses

REASONS FOR PERFORMING STUDY Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high-pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane-anaesthetised horses. There is no information on the effects of CO2 pneumoperitoneum on cardiopulmonary function and haematology, plasma chemistry and peritoneal fluid (PF) variables in standing sedated horses during laparoscopic surgery. OBJECTIVES To determine the effects of high pressure CO2 pneumoperitoneum in standing sedated horses on cardiopulmonary function, blood gas, haematology, plasma chemistry and PF variables. METHODS Six healthy, mature horses were sedated with an i.v. bolus of detomidine (0.02 mg/kg bwt) and butorphanol (0.02 mg/kg bwt) and instrumented to determine the changes in cardiopulmonary function, haematology, serum chemistry and PF values during and after pneumoperitoneum with CO2 to 15 mmHg pressure for standing laparoscopy. Each horse was assigned at random to either a standing left flank exploratory laparoscopy (LFL) with CO2 pneumoperitoneum or sham procedure (SLFL) without insufflation, and instrumented for measurement of cardiopulmonary variables. Each horse underwent a second procedure in crossover fashion one month later so that all 6 horses had both an LFL and SLFL performed. Cardiopulmonary variables and blood gas analyses were obtained 5 mins after sedation and every 15 mins during 60 mins baseline (BL), insufflation (15 mmHg) and desufflation. Haematology, serum chemistry analysis and PF analysis were performed at BL, insufflation and desufflation, and 24 h after the conclusion of each procedure. RESULTS Significant decreases in heart rate, cardiac output and cardiac index and significant increases in mean right atrial pressure, systemic vascular resistance and pulmonary vascular resistance were recorded immediately after and during sedation in both groups of horses. Pneumoperitoneum with CO2 at 15 mmHg had no significant effect on cardiopulmonary function during surgery. There were no significant differences in blood gas, haematology or plasma chemistry values within or between groups at any time interval during the study. There was a significant increase in the PF total nucleated cell count 24 h following LFL compared to baseline values for LFL or SLFL at 24 h. There were no differences in PF protein concentrations within or between groups at any time interval. CONCLUSIONS Pneumoperitoneum with CO2 during standing laparoscopy in healthy horses does not cause adverse alterations in cardiopulmonary, haematology or plasma chemistry variables, but does induce a mild inflammatory response within the peritoneal cavity. POTENTIAL RELEVANCE High pressure (15 mmHg) pneumoperitoneum in standing sedated mature horses for laparoscopic surgery can be performed safely without any short-term or cumulative adverse effects on haemodynamic or cardiopulmonary function.

Immunohistochemical and Clinical Evaluation of p53 in Canine Cutaneous Mast Cell Tumors

One hundred twenty-six cutaneous mast cell tumors obtained by excisional biopsy from 106 dogs were evaluated using immunohistochemical staining for the presence of p53 protein. A standard avidin–biotin immunohistochemical protocol was used incorporating a polyclonal antibody of rabbit origin (CM-1) as the primary antibody. Histopathologic grading of tumors was performed on hemotoxylin and eosin–stained samples. There was a significant difference in the percentage of cells staining positive for p53 for the histopathologic grades (P = 0.0005). Grade III tumors had a significantly greater p53 content than did grade I or II tumors (P < 0.05). Clinical data obtained retrospectively was available for 54 dogs. Tumor recurred in 19 of 54 (35.2%) dogs. Twenty-nine dogs died by the end of the study; 9 of 29 (31.0%) died of mast cell tumor disease. Histopathologic grade showed a significant negative association with survival time. Both clinical stage and histopathologic grade showed a significant negative association with time to recurrence. The percentage of cells staining positive for p53 did not significantly improve the forward analysis. Immunohistochemical detection of p53 did not appear useful in characterizing the clinical association between cutaneous mast cell tumor cellular features and survival time or time to tumor recurrence in dogs.

Effects of long-term phenobarbital treatment on the thyroid and adrenal axis and adrenal function tests in dogs.

Phenobarbital can interfere with the thyroid axis in human beings and rats by accelerating hepatic thyroxine metabolism because of enzyme induction. In human beings, it also can interfere with the low-dose dexamethasone suppression test (LDDST) used to assess adrenal function by accelerating dexamethasone metabolism. This effect can cause a lack of suppression of pituitary ACTH and subsequent adrenal cortisol release after dexamethasone administration. The effects of phenobarbital on the thyroid axis, the adrenal axis, and adrenal function tests were prospectively investigated in 12 normal, adult dogs. Phenobarbital was administered at 5 mg per kilogram of body weight (range, 4.8-6.6 mg/kg) PO q12h for 29 weeks, resulting in therapeutic serum concentrations (20-40 microg/mL). Serum total thyroxine (TT4), free thyroxine (FT4) by equilibrium dialysis, total triiodothyronine (TT3), thyrotropin (TSH), and cholesterol were determined before and during phenobarbital treatment. LDDST, ACTH stimulation tests, and ultrasonographic evaluation of the adrenal glands were performed before and during treatment. TT4 and FT4 decreased significantly (P < or = .05), TT3 had minimal fluctuation, TSH had only a delayed compensatory increase, and cholesterol increased during phenobarbital treatment. The delayed increase in TSH, despite persistent hypothyroxinemia, suggests that accelerated hepatic thyroxine elimination may not be the only effect of phenobarbital on the thyroid axis. There was no significant effect of phenobarbital on either of the adrenal function tests. With the methods employed, we did not find any effects of the drug on the hormonal equilibrium of the adrenal axis.

Urinary tract infection in dogs with thoracolumbar intervertebral disc herniation and urinary bladder dysfunction managed by manual expression, indwelling catheterization or intermittent catheterization.

OBJECTIVE To evaluate risk factors for lower urinary tract infection (UTI) in dogs with intervertebral disc disease (IVDD) that had manual expression (ME), indwelling catheterization (IDC) or intermittent catheterization (ITC) for urinary bladder management. STUDY DESIGN Randomized-clinical trial. ANIMALS Dogs (n=62) treated with urinary bladder dysfunction requiring surgery for IVDD and control dogs (n=30) that had surgery for reasons other than IVDD. METHODS Treated dogs were randomly assigned to ME, IDC, or ITC. Urine was collected for culture and antimicrobial susceptibility testing before and after treatment. Incidence and risk factors for UTI were evaluated. Bacterial isolates and antimicrobial resistance patterns were described. RESULTS Mean (+/-SD) time to urination was significantly longer for IDC dogs (7.4+/-2.75 days) than ME dogs (4.2+/-2.63) and ITC dogs (4.9+/-3.12). Thirteen treated dogs (21%) and no control dogs developed UTI: 4/25 (16%) ME, 8/25 (32%) IDC, and 1/12 (8%) ITC. Enterobacter sp. was most frequently isolated (4/13; 31%). Duration of treatment was the only risk factor for UTI and each additional day of treatment increased the risk of UTI 1.5 times. CONCLUSION For dogs with acute IVDD, the duration of required urinary bladder management establishes the risk of UTI, not the urinary bladder management technique. CLINICAL RELEVANCE Duration of treatment for urinary bladder dysfunction is a risk factor for UTI in dogs recovering from acute IVDD. Treatment for urinary bladder management should be limited where possible and no method of treatment is preferred. For dogs managed by IDC, voluntary urination might occur before clinically suspected.

Variability associated with repeated measurements of gastrointestinal tract motility in dogs obtained by use of a wireless motility capsule system and scintigraphy

OBJECTIVE To compare repeatability of measurements of gastrointestinal tract motility in healthy dogs obtained by use of a wireless motility capsule (WMC) and scintigraphy. ANIMALS 6 healthy adult dogs (mean +/- SD body weight, 21.5 +/- 1.8 kg). PROCEDURES A radiolabeled test meal was offered immediately after oral administration of a WMC. Serial static scintigraphic abdominal images were acquired for 270 minutes. A dedicated remote receiver was used for data collection from the WMC until the WMC was expelled in the feces. Each dog was evaluated 3 times at intervals of 1 to 2 weeks. RESULTS Mean gastric emptying half-time measured by use of scintigraphy (T(1/2)-GES) for each dog ranged from 99.9 to 181.2 minutes. Mean gastric emptying time (GET) measured by use of the WMC (GET-WMC) in each dog ranged from 385.3 to 669.7 minutes. Mean coefficient of variation was 11.8% for T(1/2)-GES and 7.8% for GET-WMC. The intraclass correlation coefficient was 69% for T(1/2)-GES and 71% for GET-WMC. Results for a nested analysis of covariance suggested that both methods were comparable for the evaluation of gastric emptying. CONCLUSIONS AND CLINICAL RELEVANCE Scintigraphy and a WMC system had similar variation for assessment of gastric emptying. Moderate intraindividual variability was detected for both methods and must be considered when interpreting test results for individual dogs. Repeatability of measurements obtained by use of the WMC was equivalent to that obtained by use of scintigraphy. The WMC system offers a nonradioactive, user-friendly method for assessment of gastric emptying in dogs.

Determination of Normal Blood Concentrations of Lead, Zinc, Copper, and Iron in Hispaniolan Amazon Parrots (Amazona ventralis)

Abstract Lead, zinc, copper, and iron toxicities are major concerns affecting both wild and captive avian populations. Reference ranges of blood concentrations of these metals in large numbers of birds with no history of environmental exposure have not been reported. This study reports ranges for whole-blood (lead) or plasma (zinc, copper, and iron) concentrations for lead, zinc, copper, and iron in 45 Hispaniolan Amazon parrots that had minimal environmental exposure to any of these metals. Measurements of plasma zinc, copper, and iron concentrations followed a normal distribution, which resulted in reference ranges (mean ± 2 SD) of 1.25–2.29 ppm, 0.07–0.19 ppm, and 2.25–6.25 ppm, respectively. All whole-blood lead concentrations were below 0.02 ppm, and a reference range could not be determined.