Electrocoagulative removal of endometrial cysts in the mare

Six mares had endometrial cysts removed by endoscopic electrocoagulative surgery. These mares exhibited poor reproductive histories and endometrial cysts were the only detectable abnormalities. In each case, at least two cysts greater than 2.5cm were present. One mare subsequently produced a live foal; two are presently in foal; one conceived but absorbed; one formed more cysts after surgery; and one has not yet been bred. Histologically, the walls of the cysts contained entire lamina propria, relatively normal endometrial glands, and small cystic spaces.     

Primary Hypoadrenocorticism in Ten Cats

Primary hypoadrenocorticism was diagnosed in ten young to middle-aged cats of mixed breeding. Five of the cats were male, and five were female. Historic signs included lethargy (n = 10), anorexia (n = 10), weight loss (n = 9), vomiting (n = 4), and polyuria (n = 3). Dehydration (n = 9), hypothermia (n = 8), prolonged capillary refill time (n = 5), weak pulse (n = 5), collapse (n = 3), and sinus bradycardia (n = 2) were found on physical examination. Results of initial laboratory tests revealed anemia (n = 3), absolute lymphocytosis (n = 2), absolute eosinophilia (n = 1), and azotemia and hyperphosphatemia (n = 10). Serum electrolyte changes included hyponatremia (n = 10), hyperkalemia (n = 9), hypochloremia (n = 9), and hypercalcemia (n = 1). The diagnosis of primary adrenocortical insufficiency was established on the basis of results of adrenocorticotropic hormone (ACTH) stimulation tests (n = 10) and endogenous plasma ACTH determinations (n = 7). Initial therapy for hypoadrenocorticism included intravenous administration of 0.9% saline and dexamethasone and intramuscular administration of desoxycorticosterone acetate in oil. Three cats were euthanatized shortly after diagnosis because of poor clinical response. Results of necropsy examination were unremarkable except for complete destruction of both adrenal cortices. Seven cats were treated chronically with oral prednisone or intramuscular methylprednisolone acetate for glucocorticoid supplementation and with oral fludrocortisone acetate or intramuscular injections of repository desoxycorticosterone pivalate for mineralocorticoid replacement. One cat died after 47 days of therapy from unknown causes; the other six cats are still alive and well after 3 to 70 months of treatment.     

EVALUATION OF HEART TIME-ACTIVITY CURVES AS A PREDICTOR OF HEPATIC EXTRACTION OF 99mTc-MEBROFENIN IN DOGS

In this study, heart time-activity curve, created following intravenous injection of 99mTc-mebrofenin were used to quantify hepatic function in normal dogs and dogs with induced hepatic parenchymal cell damage. The results were compared to a direct measurement of hepatic extraction following mesenteric venous injection of 99mTc-mebrofenin. The heart time-activity curves were normalized and the area under the curve from 0-30 minutes and 0-60 minutes were determined. In addition, the half-time clearance rate of the heart time-activity curve was analyzed using a two-compartment model. Linear regression analysis was used to describe the relationship between the area under the normalized heart time-activity curve and hepatic extraction. There was good correlation between the area under the normalized heart time-activity curve and hepatic extraction. The best correlation was obtained from the 0-30 minute data (r2 = 0.92). A formula for calculating hepatic extraction was derived using linear regression analysis: Hepatic extraction = 1.092 - (0.0000308 x AUC0-30 minutes). There was good correlation between the half-time clearance rates from the heart time-activity curve and hepatic extraction. The best correlation was between the fast phase half-time clearance and hepatic extraction (r2 = 0.88). The area under a normalized heart time-activity curve can be used as a simple alternative to deconvolutional analysis for the determination of hepatic extraction as a measure of hepatic parenchymal cell function in the dog.     

Radiation Therapy of Canine Brain Masses

This article evaluates the responses of 14 dogs with brain masses using orthovoltage irradiation for definitive treatment. Dogs were anesthetized for computed tomography (CT) examination, formation of head immobilization and positioning devices, radiation treatment simulation, and treatments. Total doses of 39 Gy (9 dogs) or 45 Gy (5 dogs) to the tumor were administered over 25 to 41 days. Two or three portals (parallel opposed lateral with or without a dorsal field) were used. Treatment volumes included the tumor and peritumoral edema, as determined by CT scan, and a 1-cm margin. Histopathologic diagnoses were available in 9 of 14 dogs. There were 4 meningiomas, 1 lymphosarcoma, 1 pituitary adenoma, 1 metastatic anaplastic carcinoma, 1 anaplastic oligodendroglioma and 1 dog with granuloma-tous meningoencephalitis. At the end of radiation therapy, 10 dogs could be evaluated for progression of clinical signs: 3 dogs deteriorated or failed to improve, and 7 dogs improved. At the time of analysis, all dogs were dead. Mean and median survival times, measured from the beginning of radiation, were 345 and 489 days, respectively. This was compared with mean survival times of 30 to 81 days reported in the literature for dogs with brain tumors that did not receive treatment. The median survival time of 9 dogs treated with 39 Gy was 153 days, versus 519 days for 5 dogs that received 45 Gy. It appears that radiation therapy prolongs survival times for dogs with brain masses. Although megavoltage therapy would be optimal, orthovoltage radiation can be applied in total doses of 45 Gy in 3.75 Gy fractions over 28 days without adverse effects. Histopathologic evidence of multifocal demyelination and astrocytosis may be found. (Journal of Veterinary Internal Medicine 1993; 7:216–219. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Rhinocerebral and nasal zygomycosis in sheep caused by Conidiobolus incongruus

The clinical findings, pathology and mycology of a cluster of 5 ovine cases of rhinocerebral and nasal zygomycosis caused by Conidiobolus incongruus are described. All cases were in Border Leicester or Merino x Border Leicester ewes from a flock pastured in a low-lying paddock adjoining a small tidal river in subtropical Queensland (latitude 28 degrees S). These cases of zygomycosis are believed to be the first infections due to C incongruus recorded in animals other than humans. The disease was subacute in 4 animals with a course of up to several weeks. In these, the primary site of infection was the posterior nasal cavity. The lesions extended to the dorsum of the face between the eyes, to the orbital cavity and to the anterior brain and meninges in the cranial cavity. In one animal, where the anterior nasal cavity was affected and iodine treatment used, the course was longer. The fungal granulomas had numerous foreign body giant cells, neutrophils and eosinophils. Fungal hyphae were thin walled, 6 to 8 microns in diameter, with occasional septa and irregular branching. They were cuffed with a wide zone of necrotic cell coagulum, or with homogeneous eosinophilic Splendore-Hoeppli granules.     

ULTRASOUND APPEARANCE AND EARLY DETECTION OF Vx2 CARCINOMA IN THE RABBIT KIDNEY

Vx2 carcinoma was induced in the rabbit kidney by percutaneous injection of a tumor-cell suspension. A focal renal mass similar in appearance to spontaneous renal carcinoma was produced. The mass could be detected with ultrasound as early as one week post injection, however it could not be identified until two weeks post injection using renal angiography and excretory urography. The renal tumor was recognized with ultrasound as an alteration in the cortical outline and obliteration of the renal medulla. A small amount of perirenal fluid was identified at two weeks. Intra-and extrarenal tumors were evident at three weeks with hypoechoic and anechoic areas evident within the large extrarenal mass observed four weeks post injection. Hypoechoic areas observed with ultrasound corresponded to areas of necrosis and hemorrhage while anechoic areas represented fluid accumulation within and around the tumor. Transplanted tumors were detected by ultrasound before they were evident on either the renal angiogram or excretory urogram. Ultrasound is useful as a screening procedure when renal tumor is suspected.     

The Influence of Detomidine and Epinephrine on Heart Rate, Arterial Blood Pressure, and Cardiac Arrhythmia in Horses

Detomidine (10 micrograms/kg and 20 micrograms/kg) was administered to seven horses with and without epinephrine infusion (0.1 microgram/kg/min) from 5 minutes before to 5 minutes after detomidine injection. One or more single supraventricular premature heartbeats were observed in three horses after detomidine administration. Epinephrine infusion did not modify the incidence of cardiac arrhythmias in detomidine-treated horses at the doses tested. Relatively high momentary peak systolic pressures were registered in some horses after detomidine administration during epinephrine infusion. The highest systolic arterial blood pressure was 290 mm Hg, but this value was not higher than that reported in horses during maximum physical exercise. Epinephrine infusion did not alter blood gases, arterial pH, or base excess.