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- Author or Editor: David C. Twedt x
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Abstract
Objective—To determine the effect of oral administration of a silibinin-phosphatidylcholine complex (SPC) on oxidative stress in leukocytes and granulocyte function in healthy cats.
Animals—10 purpose-bred adult cats.
Procedures—Cats were administered SPC (10 mg/kg/d) orally for 5 days; blood samples were collected prior to and immediately after the 5-day treatment period. Leukocytes were incubated with monochlorobimane for detection of reduced glutathione (GSH) via flow cytometry. Leukocytes were also incubated with dihydrorhodamine 123 and mixed with Escherichia coli conjugated to a fluorescent marker to measure E coli phagocytosis and the subsequent oxidative burst via flow cytometry. Activities of the antioxidant enzymes superoxide dismutase and glutathione peroxidase, along with the reduced glutathione-to-oxidized glutathione (GSH:GSSG) ratio and a measure of lipid peroxidation (malondialdehyde concentration [Mmol/L of blood]), were measured spectrophotometrically.
Results—The mean fluorescence intensity (MFI), representing GSH content, increased significantly in feline lymphocytes and granulocytes following 5 days of oral administration of SPC. Mean ± SD lymphocyte MFI significantly increased from 27.8 ± 9.0 to 39.6 ± 6.7, and the granulocyte MFI increased from 508.6 ± 135.6 to 612.1 ± 122.9. Following 5 days of SPC administration, the percentage of phagocytic cells that were responding optimally significantly increased (from 37 ± 11.8% to 45 ± 17.5%). Other measures of oxidative stress did not change significantly.
Conclusions and Clinical Relevance—In cats, oral administration of supplemental SPC appears to increase granulocyte GSH content and phagocytic function, both of which would be potentially beneficial in cats with diseases associated with oxidative stress.
Abstract
Objective—To evaluate changes in pH of peritoneal fluid associated with CO2 insufflation during laparoscopy in dogs.
Animals—13 client-owned dogs and 10 purpose-bred teaching dogs.
Procedures—Laparotomy was performed on control dogs; peritoneal fluid pH was mea-sured at time of incision of the abdominal cavity (time 0) and 30 minutes later. Laparoscopic insufflation with CO2 was performed and routine laparoscopic procedures conducted on the teaching dogs. Insufflation pressure was limited to 12 mm Hg. Intraperitoneal fluid pH was measured by use of pH indicator paper at 4 time points. Arterial blood gas analysis was performed at the same time points.
Results—Peritoneal fluid pH did not change significantly between 0 and 30 minutes in the control dogs. For dogs with CO2 insufflation, measurements obtained were a mean of 8.5, 24.5, 44.5, and 72.0 minutes after insufflation. The pH of peritoneal fluid decreased signifi-cantly between the first (7.825 ± 0.350) and second (7.672 ± 0.366) time point. Blood pH decreased significantly between the first (7.343 ± 0.078), third (7.235 ± 0.042), and fourth (7.225 ± 0.038) time points. The PaCO2 increased significantly between the first (39.9 ± 9.8 mm Hg) and fourth (54.6 ± 4.4 mm Hg) time points. Base excess decreased significantly between the first and all subsequent time points.
Conclusions and Clinical Relevance—Pneumoperitoneum attributable to CO2 insufflation caused a mild and transient decrease in peritoneal fluid pH in dogs. Changes in peritoneal fluid associated with CO2 insufflation in dogs were similar to those in other animals.
Abstract
OBJECTIVE
To evaluate the feasibility of contrast-enhanced CT for assessment of pancreatic perfusion in healthy dogs.
ANIMALS
6 healthy purpose-bred female Treeing Walker Coonhounds.
PROCEDURES
Contrast-enhanced CT of the cranial part of the abdomen was performed with 3-mm slice thickness. Postprocessing computer software designed for evaluation of human patients was used to calculate perfusion data for the pancreas and liver by use of 3-mm and reformatted 6-mm slices. Differences in perfusion variables between the pancreas and liver and differences in liver-specific data of interest were evaluated with the Friedman test.
RESULTS
Multiple pancreatic perfusion variables were determined, including perfusion, peak enhancement index, time to peak enhancement, and blood volume. The same variables as well as arterial, portal, and total perfusion and hepatic perfusion index were determined for the liver. Values for 6-mm slices appeared similar to those for 3-mm slices. The liver had significantly greater median perfusion and peak enhancement index, compared with the pancreas.
CONCLUSIONS AND CLINICAL RELEVANCE
Measurement of pancreatic perfusion with contrast-enhanced CT was feasible in this group of dogs. Hepatic arterial and pancreatic perfusion values were similar to previously published findings for dogs, but hepatic portal and hepatic total perfusion measurements were not. These discrepancies might have been attributable to physiologic differences between dogs and people and related limitations of the CT software intended for evaluation of human patients. Further research is warranted to assess reliability of perfusion variables and applicability of the method for assessment of canine patients with pancreatic abnormalities.
Abstract
Objective
To investigate the effects of experimentally induced acute gastric dilatation on electrical and mechanical activities of the stomach in dogs.
Animals
7 healthy dogs.
Procedure
Electrodes and strain-gauge force transducers were implanted on the serosal surface of the antrum and pylorus. Eight days later, baseline gastric electrical and contractile activities were recorded. The dogs were anesthetized and mechanically ventilated to maintain normocapnia while the stomach was distended (intragastric pressure, 30 mm Hg) for 180 minutes, using a thin compliant bag. Gastric electrical and contractile activities were recorded again on days 1 and 10 after dilatation. Recordings were analyzed to determine gastric slow-wave frequency, slow-wave dysrhythmia, propagation velocity of slow-waves, coupling of contractions to slow waves, motility index on the basis of relative contractile amplitudes, and onset of contractions after a standardized meal.
Results
Electrical or contractile activities were not significantly different 18 hours after acute gastric dilatation (day 1). Arrhythmias were evident before and after gastric dilatation in dogs from which food was withheld and in dogs after consumption of a meal.
Conclusions
Variables for assessing gastric electrical and contractile activities were unaffected 18 hours after acute gastric dilatation.
Clinical Relevance
Analysis of results of this study indicated that altered electrical and contractile activities in dogs with short-term gastric dilatation are not likely to be secondary to the process of acute gastric dilatation. (Am J Vet Res 1999;60:597–602)
Abstract
Objective—To determine the anesthetic-sparing effect of maropitant, a neurokinin 1 receptor antagonist, during noxious visceral stimulation of the ovary and ovarian ligament in dogs.
Animals—Eight 1-year-old female dogs.
Procedures—Dogs were anesthetized with sevoflurane. Following instrumentation and stabilization, the right ovary and ovarian ligament were accessed by use of laparoscopy. The ovary was stimulated with a traction force of 6.61 N. The minimum alveolar concentration (MAC) was determined before and after 2 doses of maropitant.
Results—The sevoflurane MAC value was 2.12 ± 0.4% during stimulation without treatment (control). Administration of maropitant (1 mg/kg, IV, followed by 30 μg/kg/h, IV) decreased the sevoflurane MAC to 1.61 ± 0.4% (24% decrease). A higher maropitant dose (5 mg/kg, IV, followed by 150 μg/kg/h, IV) decreased the MAC to 1.48 ± 0.4% (30% decrease).
Conclusions and Clinical Relevance—Maropitant decreased the anesthetic requirements during visceral stimulation of the ovary and ovarian ligament in dogs. Results suggest the potential role for neurokinin 1 receptor antagonists to manage ovarian and visceral pain.
Abstract
Objective
To investigate the effects of metoclopramide, a putative gastroprokinetic agent, on dogs that had recovered from gastric dilatation-volvulus (GDV), a disorder characterized by delayed gastric emptying.
Animals
6 healthy dogs and 5 dogs after treatment and recovery from GDV.
Procedure
Baseline recordings of gastric electrical and contractile activities were made 8 or 10 days after circumcostal gastropexy and implantation of serosal electrodes and strain-gauge force transducers. Gastric activities were recorded again the next day after treatment with the clinically recommended oral metoclopramide dose (0.3 mg/kg of body weight) administered a half hour before feeding. Recordings were analyzed to determine gastric slow-wave frequency, presence of slow-wave dysrhythmia, slow-wave propagation velocity, coupling of contractions to slow waves, a motility index based on relative contractile amplitudes, and onset of contractions after a standardized meal.
Results
Significant differences in gastric electrical or contractile activities were not detected after metoclopramide treatment in dogs with GDV. Compared with control dogs after metoclopramide treatment, gastric slow-wave propagation velocity was significantly (P = 0.03) faster for the dogs with GDV at postprandial minute 90.
Conclusion
At a clinically recommended dosage, metoclopramide treatment did not change gastric myoelectric and motor activities in a way that would promote increased gastric emptying in dogs with GDV.
Clinical Relevance
Metoclopramide treatment may not benefit dogs with GDV and delayed gastric emptying. (Am J Vet Res 1996;57:1616–1622)
Abstract
Objective—To evaluate antioxidant capacity and inflammatory cytokine gene expression in horses fed silibinin complexed with phospholipid.
Animals—5 healthy horses.
Procedures—Horses consumed increasing orally administered doses of silibinin phospholipid during 4 nonconsecutive weeks (0 mg/kg, 6.5 mg/kg, 13 mg/kg, and 26 mg/kg of body weight, twice daily for 7 days each week). Dose-related changes in plasma antioxidant capacity, peripheral blood cell glutathione concentration and antioxidant enzyme activities, and blood cytokine gene expression were evaluated.
Results—Plasma antioxidant capacity increased throughout the study period with increasing dose. Red blood cell nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase I activity decreased significantly with increasing doses of silibinin phospholipid. No significant differences were identified in glutathione peroxidase activity, reduced glutathione or oxidized glutathione concentrations, or expression of tumor necrosis factor α, interleukin-1, or interleukin-2.
Conclusions and Clinical Relevance—Minor alterations in antioxidant capacity of healthy horses that consumed silibinin phospholipid occurred and suggest that further study in horses with liver disease is indicated.
SUMMARY
To evaluate the sensitivity and specificity of 2 commercial test kits for detection of occult blood in canine feces, various volumes of blood were administered to 6 dogs via orogastric tube. Blood volumes tested were chosen on the basis of hemoglobin quantities of 5, 10, 20, 200, 350, and 500 mg of hemoglobin/kg of body weight. Fecal specimens were collected twice daily and analyzed separately by 2 observers for the presence of occult blood by use of modified guaiac and orthotolodine tablet tests, and for melena by visual inspection. Five dogs given blood at the rate of 500 mg of hemoglobin/kg and 1 dog given blood at the rate of 350 mg of hemoglobin/kg developed melena. Results of both occult blood tests were positive in 2 of 6 dogs given blood at the rate of 5 mg of hemoglobin/kg. Five of 6, and 4 of 6 dogs given blood at the rate of 10 mg hemoglobin/kg had positive test results by modified guaiac and orthotolodine methods, respectively. Results of both methods were positive in all dogs given blood at the rate of 20 mg of hemoglobin/kg. There was 86% agreement between the 2 observers’ results for the modified guaiac method, and 78% agreement for the orthotolodine method. There was 77% agreement of results between the 2 test methods. Gastrointestinal transit time decreased with increasing volumes of blood. Occult blood testing was found to be useful for detection of blood in feces at volumes 20 to 50 times less than that required to cause melena.
SUMMARY
Using radiopaque particles mixed with food, gastric emptying was assessed in healthy dogs not subjected to surgery, in healthy dogs 9 to 35 days after circumcostal gastropexy, and, in dogs 1 to 54 months after surgical treatment and recovery from gastric dilatation-volvulus (gdv). Circumcostal gastropexy surgery did not alter the 90% gastric emptying time for radiopaque particles in healthy dogs. However, 90% gastric emptying time was significantly (P < 0.05) increased after circumcostal gastropexy in dogs with gdv, compared with healthy dogs after the same surgical procedure and recovery period. These results imply that dogs with gdv have delayed gastric emptying of solid particles. Whether delayed gastric emptying of markers detected in affected dogs after surgical treatment and recovery was the result or the cause of gdv was not determined.
Results indicate that circumcostal gastropexy could be recommended as a prophylactic procedure for gdv in large breeds with deep thorax, because delayed gastric emptying of markers secondary to the surgical procedure is unlikely.
Abstract
Objective—To determine the oral bioavailability, single and multidose pharmacokinetics, and safety of silibinin, a milk thistle derivative, in healthy horses.
Animals—9 healthy horses.
Procedures—Horses were initially administered silibinin IV and silibinin phospholipid orally in feed and via nasogastric tube. Five horses then consumed increasing orally administered doses of silibinin phospholipid during 4 nonconsecutive weeks (0 mg/kg, 6.5 mg/kg, 13 mg/kg, and 26 mg/kg of body weight, twice daily for 7 days each week).
Results—Bioavailability of orally administered silibinin phospholipid was 0.6% PO in feed and 2.9% via nasogastric tube. During the multidose phase, silibinin had nonlinear pharmacokinetics. Despite this, silibinin did not accumulate when given twice daily for 7 days at the evaluated doses. Dose-limiting toxicosis was not observed.
Conclusions and Clinical Relevance—Silibinin phospholipid was safe, although poorly bio-available, in horses. Further study is indicated in horses with hepatic disease.