Search Results

You are looking at 21 - 30 of 49 items for

  • Author or Editor: Dawn Boothe x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

Abstract

Objective—To document blood nitric oxide concentrations in the portal vein and systemic circulation in a rat model of acute portal hypertension and compare values with a control group and a sham surgical group.

Animals—30 rats; 10 controls (group 1), 10 sham surgical (group 2), and 10 rats with surgically induced acute portal hypertension (group 3).

Procedure—Following induction of anesthesia, catheters were placed surgically in the carotid artery, jugular, and portal veins of group 2 and 3 rats and in the carotid artery and jugular vein of group 1 rats. Baseline heart and respiratory rates, rectal temperature, and vascular pressure measurements were obtained, and blood was drawn from all catheters for baseline nitric oxide (NO) concentrations. Acute portal hypertension was induced in the group 3 rats by tying a partially occluding suture around the portal vein and a 22-gauge catheter. The catheter was then removed, resulting in a repeatable degree of portal vein impingement. After catheter placement, all variables were remeasured at 15-minute intervals for 3 hours.

Results—Blood nitric oxide concentrations were greater in all vessels tested in group 3 than in group 2 rats.

Conclusions and Clinical Relevance—Acute portal hypertension in this experimental model results in increased concentrations of NO in the systemic and portal circulation. On the basis of information in the rat, it is possible that increased NO concentrations may develop in dogs following surgical treatment of congenital portosystemic shunts if acute life-threatening portal hypertension develops. Increased NO concentrations may contribute to the shock syndrome that develops in these dogs. (Am J Vet Res 2000;61:1173–1177)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine concentrations of marbofloxacin in alveolar macrophages (AMs) and epithelial lining fluid (ELF) and compare those concentrations with plasma concentrations in healthy dogs.

Animals—12 adult mixed-breed and purebred hounds.

Procedure—10 dogs received orally administered marbofloxacin at a dosage of 2.75 mg/kg every 24 hours for 5 days. Two dogs served as nontreated controls. Fiberoptic bronchoscopy and bronchoalveolar lavage procedures were performed while dogs were anesthetized with propofol, approximately 6 hours after the fifth dose. The concentrations of marbofloxacin in plasma and bronchoalveolar fluid (cell and supernatant fractions) were determined by use of high-performance liquid chromatography with detection of fluorescence.

Results—Mean ± SD plasma marbofloxacin concentrations 2 and 6 hours after the fifth dose were 2.36 ± 0.52 µg/mL and 1.81 ± 0.21 µg/mL, respectively. Mean ± SD marbofloxacin concentration 6 hours after the fifth dose in AMs (37.43 ± 24.61 µg/mL) was significantly greater than that in plasma (1.81 ± 0.21 µg/mL) and ELF (0.82 ± 0.34 µg/mL), resulting in a mean AM concentration-to-plasma concentration ratio of 20.4, a mean AM:ELF ratio of 60.8, and a mean ELF-to-plasma ratio of 0.46. Marbofloxacin was not detected in any samples from control dogs.

Conclusions and Clinical Relevance—Marbofloxacin concentrations in AMs were greater than the mean inhibitory concentrations of major bacterial pathogens in dogs. Results indicated that marbofloxacin accumulates in AMs at concentrations exceeding those reached in plasma and ELF. The accumulation of marbofloxacin in AMs may facilitate treatment for susceptible intracellular pathogens or infections associated with pulmonary macrophage infiltration. (Am J Vet Res 2005;66:1770–1774)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate efficacy and safety of using transdermal fentanyl patches (TFP) for analgesia in cats undergoing onychectomy.

Design—Randomized controlled clinical trial.

Animals—45 client-owned cats weighing ≥ 2.7 kg (5.9 lb) undergoing onychectomy, onychectomy and ovariohysterectomy, or onychectomy and castration.

Procedure—Cats were randomly assigned to be treated with a TFP (25 µg/h) or butorphanol; TFP were applied a minimum of 4 hours before surgery (approx 8 hours prior to extubation). Rectal temperature, heart rate, respiratory rate, force applied by the forelimbs, and serum fentanyl concentration were measured, and temperament, recovery, degree of sedation, severity of pain, severity of lameness, and appetite were scored before and periodically for up to 40 hours after surgery.

Results—Cats treated with a TFP had better recovery scores at 2 of 4 evaluation times, lower sedation scores at 2 of 8 evaluation times, and lower pain scores at 6 of 8 evaluation times, compared with cats treated with butorphanol. Use of a pressure-sensitive mat to evaluate force applied by the forelimbs did not reveal any differences between groups but did reveal a significant difference between preoperative and postoperative values. Mean ± SD serum fentanyl concentrations were 1.56 ± 1.08, 4.85 ± 2.38, 4.87 ± 1.56, and 4.35 ± 2.97 ng/ml approximately 8, 24, 32, and 48 hours, respectively, after TFP placement.

Conclusion and Clinical Relevance—Results suggest that use of a TFP (25 µg/h) for postoperative analgesia in cats undergoing onychectomy with or without surgical sterilization is safe and effective. (J Am Vet Med Assoc 2000;217:1013–1020)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate differences in bacterial numbers, identity, and susceptibility in samples obtained from the tympanic cavity on entry (preflush) and after evacuation and lavage (postflush) and assess perioperative and empiric antimicrobial selection in dogs that underwent total ear canal ablation (TECA) with lateral bulla osteotomy (LBO) or reoperation LBO.

Design—Prospective clinical study.

Animals—34 dogs.

Procedure—TECA with LBO or reoperation LBO was performed on 47 ears. Pre- and postflush aerobic and anaerobic samples were obtained from the tympanic cavity. Isolates and antimicrobial susceptibility patterns were compared.

Results—Different isolates (31/44 [70%] ears) and susceptibility patterns of isolate pairs (6/44 [14%] ears) were detected in pre- and postflush samples from 84% of ears. Evacuation and lavage of the tympanic cavity decreased the number of bacterial isolates by 33%. In 26% of ears, bacteria were isolated from postflush samples but not preflush samples. Only 26% of isolates tested were susceptible to cefazolin. At least 1 isolate from 53% of dogs that received empirically chosen antimicrobials postoperatively was resistant to the selected drugs. Anaerobic bacteria were recovered from 6 ears.

Conclusions and Clinical Relevance—Accurate microbiologic assessment of the tympanic cavity should be the basis for selection of antimicrobials in dogs undergoing TECA with LBO. Bacteria remain in the tympanic cavity after evacuation and lavage. Cefazolin was a poor choice for dogs that underwent TECA with LBO, as judged on the basis of culture and susceptibility testing results. (J Am Vet Med Assoc 2005;227:748–755)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effect of treatment approach on outcome and the appropriateness of initial empirical antimicrobial treatment in dogs with pyothorax.

Design—Retrospective case series.

Animals—46 dogs with pyothorax confirmed by either (n = 15) or both (31) of the following: intracellular bacteria in pleural fluid or tissue (41) and bacteria recovered via culture of pleural fluid (36).

Procedures—Medical records of dogs treated for pyothorax from 1983 through 2001 were reviewed. Data on signalment, history, clinical signs, and treatment and results of diagnostic imaging and cytologic and microbiological evaluations were obtained. Follow-up was performed via reexamination (n = 15) and contact with referring veterinarians (26) and owners (24).

Results—46 dogs were treated with at least 1 antimicrobial and thoracocentesis (n = 7; noninvasive group), a thoracostomy tube (26; invasive group) with or without pleural lavage and heparin, or a thoracotomy (13; surgical group) and thoracostomy tube with or without pleural lavage and heparin. Pyothorax recurred in 7 dogs, and 5 of the 7 died or were euthanatized. In the respective groups, the short-term survival rate was 29%, 77%, and 92% and the long-term survival rate was 29%, 71%, and 70%. Pleural lavage and heparin treatment increased the likelihood of short- and long-term survival. Results of antimicrobial susceptibility testing suggested empirical antimicrobial selection was associated with a 35% risk of inefficacy.

Conclusions and Clinical Relevance—In the dogs with pyothorax in this study, favorable treatment effects were achieved with surgery (for short-term survival) and pleural lavage and heparin treatment (for short- and long-term survival). Findings failed to support the hypothesis that invasive (surgical) versus noninvasive treatment of pyothorax in dogs leads to a better long-term outcome.

Full access
in Journal of the American Veterinary Medical Association

Summary

To measure tracheal mucociliary transport rate (tmtr) in awake dogs, restrained in dorsal recumbency 99mtechnetium-labeled macroaggregated albumin was administered by tracheal injection, and the cephalic movement of boluses containing the radiopharmaceutical was detected by a gamma camera positioned lateral to the dog's head and neck. The distance traveled by each bolus was measured, relative to external markers placed a known distance apart. Tracheal mucociliary transport rates were calculated by dividing the measured distance of radiopharmaceutical movement by elapsed time. The technique was efficient and well tolerated. Mean (± sd) tmtr was 35.3 ± 15.9 mm/min. Significant (P = 0.029) difference in tmtr was found between males and females, but significant difference attributable to age of the dog was not detected. This method of measuring tmtr in awake dogs has potential for evaluation of clinical animal patients with suspected tracheal mucociliary abnormalities.

Free access
in American Journal of Veterinary Research

Summary

Effects of vena caval banding on portal venous and vena caval hemodynamics were examined in 6 control dogs and in 10 dogs that had undergone attenuation (banding) of the abdominal part of the caudal vena cava and had dimethylnitrosamine-induced multiple portosystemic shunts (pss). Additionally, indocyanine green (icg) extraction and clearance after infusion to steady state were used to calculate hepatic plasma flow in these dogs. Sixteen dogs were randomly assigned to 2 groups: control (n = 6) or diseased(n= 10). Diseased dogs were administered dimethylnitrosamine (2 mg/kg, po, twice weekly) until multiple pss developed, as assessed by results of clinical laboratory tests, ultrasonography, and hepatic scintigraphy. Shunts were confirmed visually at celiotomy and by contrast portography. Venous pressures (caudal vena caval, portal, and hepatic) were recorded before and after vena caval banding for up to 7 days in dogs from both groups. Peritoneal cavity pressures were recorded in all dogs after closure of the body wall. To determine icg extraction and clearance, a bolus injection of icg (0.5 mg/kg, iv) was administered, followed by steady-state infusion of 0.097 mg/min. Extractions and clearances of icg were measured, and from these, hepatic plasma flow rates were determined immediately before and after banding and at 6 hours, 48 hours, and 7 days after banding.

The gradient (caudal vena caval pressure within 1 to 2 mm of Hg of portal pressure) between caudal vena cava and portal venous pressures established at banding was maintained after the first hour in both groups. Caudal vena cava pressures established at banding were maintained throughout the study, with the exception of the first hour in diseased dogs. Extraction ratios were higher in control dogs at all times, except at 48 hours. Clearance was higher in control dogs at all times. Hepatic plasma flow did not differ between groups, except immediately after banding, when flow was greater in diseased dogs, and differences were not found over time in either group. This study indicated that vena caval banding in this model of experimentally induced multiple pss increases and maintains caudal vena cava pressure, relative to portal venous pressure (after the first hour) for 7 days, and that calculated hepatic plasma flow is not persistently improved by vena caval banding.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To describe the disposition of and pharmacodynamic response to atenolol when administered as a novel transdermal gel formulation to healthy cats.

Animals—7 healthy neutered male client-owned cats.

Procedures—Atenolol was administered either orally as a quarter of a 25-mg tablet or as an equal dose by transdermal gel. Following 1 week of treatment, an ECG and blood pressure measurements were performed and blood samples were collected for determination of plasma atenolol concentration at 2 and 12 hours after administration.

Results—2 hours after oral administration, 6 of 7 cats reached therapeutic plasma atenolol concentrations with a mean peak concentration of 579 ± 212 ng/mL. Two hours following transdermal administration, only 2 of 7 cats reached therapeutic plasma atenolol concentrations with a mean peak concentration of 177 ± 123 ng/mL. The difference in concentration between treatments was significant. Trough plasma atenolol concentrations of 258 ± 142 ng/mL and 62.4 ± 17 ng/mL were achieved 12 hours after oral and transdermal administration, respectively. A negative correlation was found between heart rate and plasma atenolol concentration.

Conclusions and Clinical Relevance—Oral administration of atenolol at a median dose of 1.1 mg/kg every 12 hours (range, 0.8 to 1.5 mg/kg) in cats induced effective plasma concentrations at 2 hours after treatment in most cats. Transdermal administration provided lower and inconsistent plasma atenolol concentrations. Further studies are needed to find an effective formulation and dosing scheme for transdermal administration of atenolol.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare pharmacokinetics of levetiracetam in serum and CSF of cats after oral administration of extended-release (ER) levetiracetam.

ANIMALS

9 healthy cats.

PROCEDURES

Cats received 1 dose of a commercially available ER levetiracetam product (500 mg, PO). Thirteen blood and 10 CSF samples were collected over a 24-hour period for pharmacokinetic analysis. After 1 week, cats received 1 dose of a compounded ER levetiracetam formulation (500 mg, PO), and samples were obtained at the same times for analysis.

RESULTS

CSF concentrations of levetiracetam closely paralleled serum concentrations. There were significant differences between the commercially available product and the compounded formulation for mean ± SD serum maximum concentration (Cmax; 126 ± 33 μg/mL and 169 ± 51 μg/mL, respectively), Cmax corrected for dose (0.83 ± 0.10 μg/mL/mg and 1.10 ± 0.28 μg/mL/mg, respectively), and time to Cmax (5.1 ± 1.6 hours and 3.1 ± 1.5 hours, respectively). Half-life for the commercially available product and compounded formulation of ER levetiracetam was 4.3 ± 2.0 hours and 5.0 ± 1.6 hours, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

The commercially available product and compounded formulation of ER levetiracetam both maintained concentrations in healthy cats 12 hours after oral administration that have been found to be therapeutic in humans (ie, 5 μg/mL). Results of this study supported dosing intervals of 12 hours, and potentially 24 hours, for oral administration of ER levetiracetam to cats. Monitoring of serum concentrations of levetiracetam can be used as an accurate representation of levetiracetam concentrations in CSF of cats.

Full access
in American Journal of Veterinary Research