Cardiovascular effects and intraoperative pharmacokinetics of tramadol in sheep undergoing spinal surgery

Objective

To evaluate the pharmacokinetics of two doses of tramadol during isoflurane anaesthesia in sheep and their ability to prevent the cardiovascular response induced by surgical stimulation.

Treatment of Atrial Fibrillation in Horses: New Perspectives

Forty-one horses were treated for atrial fibrillation (AF) with 22 mg/kg quinidine sulfate via nasogastric tube every 2 hours until conversion to sinus rhythm, a cumulative dose of 88 to 132 mg/kg had been administered in 2-hour increments, or the horse had adverse or toxic effects from the drug. Treatment intervals were prolonged to every 6 hours if conversion had not occurred. Digoxin was administered before treatment if the horse had a fractional shortening ≤ 27% (3 horses), was prone to tachycardia (resting heart rate ≥ 60 beats/min) (1 horse), or had a previous history of sustained tachycardia of over 100 beats/min during prior conversion (3 horses). Digoxin was administered during day 1 of quinidine sulfate treatment if the horse developed a sustained tachycardia of over 100 beats/min during treatment (11 horses) or on day 2 if conversion had not occurred (7 horses). Plasma quinidine concentrations within 1 hour of conversion of AF to sinus rhythm ranged from 1.7 to 7.5 μg/mL (mean, 4.05± 1.6) and ranged from 1.7 to 4.7 μg/mL in 97% of horses. Most horses (92%) with plasma quinidine concentrations > 5 μg/mL exhibited an adverse or toxic effect of quinidine sulfate (clinical or electrocardiographic). There was no statistical association between plasma quinidine concentrations and sustained tachycardia (> 100 beats/min), diarrhea, or colic. Ataxia and upper respiratory tract stridor were significantly associated with plasma quinidine concentrations. In most instances (98%) conversion did not occur while toxic or adverse effects of quinidine sulfate were present or when plasma quinidine concentrations were > 5 μg/mL.     

Detection of apoptotic cells in intestines from horses with and without gastrointestinal tract disease

OBJECTIVE: To identify apoptosis in equine intestines and determine whether apoptosis is associated with gastrointestinal tract disease or a specific tissue layer of intestine. ANIMALS: 38 horses that underwent surgery or were euthanatized for small or large intestine obstruction, strangulation, or distension and 9 control horses euthanatized for reasons other than gastrointestinal tract disease or systemic disease. PROCEDURE: Specimens were collected at surgery from intestine involved in the primary lesion and distant to the primary lesion site or at necropsy from several sites including the primary lesion site. Histologic tissue sections were stained with H&E, and apoptosis was detected by use of the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. The number of apoptotic cells per hpf was counted in the mucosa, circular muscle, longitudinal muscle, and serosa. RESULTS: Apoptotic nuclei were seen in all layers of intestine. An increased number of apoptotic cells was found in the circular muscle of the intestine from horses with simple obstruction, compared with strangulating obstruction or healthy intestine. Intestine distant from a primary strangulating lesion had higher numbers of apoptotic cells than did intestine distant from a simple obstructive lesion or intestine taken at the site of a strangulating or simple obstructive lesion. CONCLUSIONS AND CLINICAL RELEVANCE: Intestine from horses with obstructing or strangulating lesions in the small intestine and large colon had high numbers of apoptotic cells possibly because of ischemic cell injury and subsequent inflammation. Whether substantial apoptosis affects intestinal function is not yet known.     

A double-blind,randomized, placebo-controlled study of pimobendan in dogs with dilated cardiomyopathy

A double-blind, randomized, placebo-controlled study was conducted to examine the effect on heart failure class and survival of pimobendan, an oral calcium-sensitizing inodilator, in dogs with dilated cardiomyopathy (DCM). Pimobendan (0.3-0.6 mg/kg body weight/d) or placebo was administered to English Cocker Spaniels (CSs; n = 10) and Doberman Pinschers (DPs: n = 10) that had DCM in addition to background therapy of furosemide, enalapril, and digoxin. Addition of pimobendan to standard triple therapy was associated with a significant improvement in heart failure class, regardless of breed (P < .02, Mann-Whitney rank sum test). Overall, 8 of 10 animals in the pimobendan-treated group, and 1 of 10 animals in the placebo group improved their heart failure status by at least I modified New York Heart Association functional class after initial stabilization (P = .005, Fisher's exact test). Pimobendan had no significant effect on survival in the CSs (P = 0.77, log-rank test), but DPs treated with pimobendan had significantly longer survival times compared with placebo (P < .02, log-rank test), with a median survival time of 329 days in the pimobendan group compared with 50 days in the placebo group, and a hazard ratio of 3.4 (95% confidence interval 1.4-39.8). Pimobendan resulted in significant improvement in heart failure class when added to standard therapy in this group of dogs with DCM, and may have contributed to improved survival in DPs.     

Sonographic diagnosis of a presumed ureteral tear in a horse

A 14-year-old thoroughbred gelding was presented for the evaluation of acute abdominal pain. Rectally, there was a soft fluctuant painful swelling dorsal to the bladder and to the right of the midline. The creatinine concentration of the peritoneal fluid was 15 mg/dl. Transrectal ultrasonographic examination of the urinary tract revealed a large collection of fluid dissecting from the pelvic portion of the right ureter ventrally through the right side of the bladder wall and into the retroperitoneal space, and a thickened right ureter and bladder wall at the level of the trigone. Cystoscopically there was moderate hemorrhage within the wall of the bladder. Ultrasonography revealed air within the retroperitoneal fluid collection after ureteral catheterization, confirming the preliminary diagnosis of a tear in the right ureter. The gelding was treated medically. After 48 h of hospitalization, nuclear scintigraphy revealed normal clearance from both kidneys and no apparent leakage from the right ureter. The ureteral tear and urinoma were monitored using transrectal ultrasound until resolution. The horse was successfully returned to racing. This case establishes the value of diagngstic ultrasound in the diagnosis and monitoring of a traumatic ureteral tear in a horse.     

Nutritional support for neonatal foals.

In recent years, equine neonatal medicine has made significant advances. The importance of nutritional support for the sick neonatal foal has been recognized, and methods of providing that sup-port have been developed. Today, the clinician has many options when designing a nutritional plan for the neonatal foal. When the foal's gut permits, enteral diets are an inexpensive source of nutrients. Under conditions where the gut requires rest, methods for delivering nutrients by the parenteral route have also been developed. In this article, the nutrition of the normal and sick foal is described. Guidelines for designing a nutritional plan are also reviewed.     

Nonbacterial thrombotic endocarditis in a ferret (Mustela putorius furo).

A 4-yr-old male ferret (Mustela putorius furo) was presented with a 3-day history of pelvic limb ataxia and weakness. A cellulitis associated with a deep bite wound was identified and initially treated with antibiotics and anti-inflammatory medication. Two weeks later, a grade IV/VI cardiac murmur was identified on physical examination. Echocardiographic examination revealed irregular thickening of the aortic valve leaflets, with normal chamber dimensions and normal systolic function. The ferret's physical condition rapidly deteriorated and it was subsequently euthanatized. Myxomatous degeneration of the aortic valve leaflets, with ulceration and vegetative lesions, and multiorgan infarctions were identified during necropsy. A bacterial etiologic agent was not identified from blood culture or histopathology. Lesions present were consistent with nonbacterial thrombotic endocarditis, a novel condition in the ferret.     

DEAE cellulose chromatographic characterization of canine serum

Canine serum samples were fractionated on DEAE cellulose using a continuous gradient system to establish a representative chromatographic pattern for normal dog serum. Serum samples were separated using decreasing pH (8.4–4.5) and increasing molarity (0.01–0.3 m) phosphate gradient and the elution pattern was obtained by spectrophotometric (280 nm) analysis of fractions. In preparative separations individual fractions were also analyzed by immunoelectrophoresis to determine the content of IgG immunoglobulins, transferrin and albumin. The results demonstrate a distinctly different chromatographic pattern from that of human serum. The size of the first eluting peak and the position of subsequent peaks of canine serum differ from human serum chromatograms. Fraction analyses demonstrate that this difference is due in part to the content of the various peaks and indicates a difference in electrophoretic mobility of corresponding serum proteins. In addition, canine IgGa was separated free of other immunoglobulins by rechromatographing the first peak using this gradient system.     

HORNER''S SYNDROME IN THE DOG AND CAT AS AN AID TO DIAGNOSIS

Four cases of Horner's syndrome, two in dogs and two in cats, are described. Miosis, ptosis, and enophthalmos were present in three of the cases and in addition, protrusion of the nictitating membrane was present in the fourth case. In the two cases described in cats, there was also evidence of peripheral vasodilation in the skin of the face on the same side as the Horner's syndrome.