IMAGING DIAGNOSIS—MALIGNANT PERIPHERAL NERVE SHEATH TUMOR PRESENTING AS AN INTRA‐AXIAL BRAIN MASS IN A YOUNG DOG

A 3‐year‐old Labrador retriever was presented with acute onset seizures. Magnetic resonance imaging demonstrated an intra‐axial mass affecting the right temporal lobe of the brain. Surgical resection and histopathological findings were most consistent with a malignant peripheral nerve sheath tumor. After initial recovery, deterioration 3 months post surgery prompted euthanasia. Post‐mortem revealed a mass protruding from the ventral surface of the temporal lobe, encroaching upon the optic chiasm and invading the brain. Histopathology findings were again consistent with malignant peripheral nerve sheath tumor. Although rare, this tumor should be included as a possible differential diagnosis for intra‐axial brain masses in dogs.     

Effect of post-insemination progesterone supplementation on pregnancy rate in dairy cows

Progesterone plays an important role in maintenance of pregnancy. It is hypothesized that insufficient progesterone early in pregnancy may result in embryonic loss, and that supplemental progesterone would decrease pregnancy loss in dairy cows. In Experiment 1, 84 cows and 16 heifers from a single dairy operation were selected randomly. Within each age category, controlled internal drug release (CIDR) devices were inserted into the vagina of every other female on Day 4 post-insemination and removed on Day 18 post-insemination. Transrectal ultrasonography was performed to determine pregnancy at 4 time periods [days 30 to 37 (week 5), days 44 to 51 (week 7), days 58 to 65 (week 9), and days 86 to 93 (week 13)]. Progesterone supplementation had no effect on pregnancy rate. In Experiment 2, there were no differences in progesterone concentrations between cows that did and did not receive a CIDR. Further, cows receiving CIDR devices did not have an increase in circulating progesterone concentrations 30 min or 1 h after CIDR insertion. It appears that progesterone supplementation does not increase circulating levels of progesterone in the early pregnant lactating dairy cow. Alterative methods to influence progesterone concentrations and/or early embryonic loss need to be investigated.     

Fluid therapy in vomiting and diarrhea.

Fluid therapy in the patient with vomiting and diarrhea is essential to correct hypovolemia, dehydration, acid-base imbalance, and serum electrolyte abnormalities. Prediction of acid-base or electrolyte disturbances is difficult; therefore, point of care testing is beneficial to optimize therapy. This article focuses on the pathophysiology and treatment of hypovolemia, dehydration, electrolyte disturbances, and acid-base derangements resulting from and associated with vomiting and diarrhea.     

Longevity of Bolbophorus damnificus infections in channel catfish

The digenean Bolbophorus damnificus infects commercial channel catfish Ictalurus punctatus, causing mortality, lower feed consumption, and reduced growth in surviving fish. The purpose of this study was to determine the length of time for which B. damnificus prodiplostomulum metacercariae (juvenile trematode stage that infects fish) would remain viable (parasite appearing to be intact or exhibiting movement) in channel catfish. Fish (n = 210) were infected with molecularly confirmed B. damnificus cercariae harvested from naturally infected marsh rams-horn snails Planorbella trivolvis. During the first sampling (at 20 d postinfection), 8.3 +/- 3.6 metacercariae/fish (mean +/- SD) were found in the host muscle and visceral organs. The channel catfish were then acclimated to a water temperature of either 18 degrees C or 28 degrees C. After 11 months, 6.8 +/- 3.5 and 5.9 +/- 3.0 metacercariae/fish were found in groups held at 18 degrees C and 28 degrees C, respectively. The mean number of parasites per fish did not significantly differ between fish held at the two temperatures and did not significantly decline over time at either temperature. Fish examined from 13 to 30 months postinfection all contained viable metacercariae that were morphologically and molecularly identified as B. damnificus. At 18 months, 12 metacercariae (of which 11 were intact and 10 displayed movement) were found in the one fish sampled; at 30 months, the last fish sampled contained three intact metacercariae (one displayed slight movement). Our results indicate that B. damnificus metacercariae can remain viable in channel catfish for at least an 18-30-month production cycle during which they have the potential to affect fish growth; in addition, infected fish may serve as intermediate hosts for these metacercariae for at least 2.5 years postinfection.     

Effects of reconcile (fluoxetine) chewable tablets plus behavior management for canine separation anxiety

Canine separation anxiety is a common behavioral problem presented to veterinarians. Associated behaviors are distressing to both dog and owner, have the potential to disrupt the human-companion animal bond, and may lead to euthanasia. The results of this study demonstrate the clinical efficacy and safety of Reconcile (fluoxetine, 1 to 2 mg/kg/day [0.45 to 0.91 mg/lb/day]), in conjunction with behavior management, for the treatment of canine separation anxiety. The beef flavored chewable formulation was palatable to treated dogs and easy to administer. This study provides to veterinarians and owners valuable information about an effective separation anxiety treatment plan that combines use of Reconcile with behavior modification.     

Surgery of the abomasum.

Abomasal diseases are common in cattle. Many of these diseases can be managed surgically. This article briefly discusses the various classifications of abomasal diseases. It focuses on the surgical treatment of these diseases. Surgical principles of conventional surgery and minimally invasive techniques are discussed.     

Larval cyathostominosis in horses in Ontario: an emerging disease?

From 1991 to 2003, 24 cases of larval cyathostominosis were diagnosed at postmortem in equids, 15 (63%) from 2001 to 2003. Cases occurred from September to May, the majority from October to December. Median age was 12 mo. Diarrhea, colic, and weight loss were common clinical signs. Hypoalbuminemia and microcytosis were consistent findings.     

Oxytetracycline Pharmacokinetics in Rainbow Trout during and after an Orally Administered Medicated Feed Regimen

Abstract

The pharmacokinetic–pharmacodynamic predictor of antimicrobial activity for tetracyclines is reported to be the area under the concentration–time curve at steady state (AUC_ss) divided by the minimal inhibitory concentration of the targeted pathogen. Here, we estimate AUC_ss values for oxytetracycline (OTC) in serum of rainbow trout Oncorhynchus mykiss by using a destructive sampling study design. Seventy-two rainbow trout were fed OTC-medicated feed at 74.7 ± 1.5 mg/kg (mean ± SD) body weight (BW) by oral gavage for 10 consecutive days. Serum was collected from nine fish at 1, 3, 6, 8, 10, 12, 15, and 22 d after dosing began. Serum OTC concentrations were measured by high-performance liquid chromatography with a 0.01-μg/mL limit of detection. The average OTC AUC_ss was 29.2 μg × h/mL and was estimated using nonlinear mixed-effects modeling and bootstrap resampling techniques. The elimination half-life was estimated as 85.0 h, and the fraction of steady state achieved was estimated as 0.85. The calculated AUC_ss (24.8 μg × h/mL) following 10 d of oral dosing with 75 mg OTC/kg BW was less than the estimated AUC_ss. Results suggest that the pharmacokinetics of OTC exposure, including the AUC_ss, is better evaluated by using multiday dosimetry than by using a standard single-dose protocol.

Received September 29, 2011; accepted January 30, 2012