Diagnosis of insulinoma in the dog: A study of 11 cases

The use of an intravenous glucose tolerance test (IVGTT) is described in 11 confirmed cases of insulinoma. Basal plasma glucose and serum insulin concentrations, glucose half-life (t.J and fractional clearance rate (k-value) were determined in the affected animals and seven healthy dogs. A fasting plasma glucose concentration of 3 mmol/litre or less with a coexisting serum insulin concentration greater than 20 mU/litre, and an insulin:glucose ratio (IGR) greater than 4-2 U/mol were considered to be diagnostic for insulinoma. Although there was a narrow area of overlap in the U₂ and k-values between normal and affected animals, a t.,₂ of less than 20 minutes with a k-value of more than 3 per cent/minute were also highly suggestive of insulinoma. The insulinogenic index (δI/δG) was too variable to be of diagnostic significance. Contrary to previous reports, it appears that insulin-secreting tumours retain a degree of responsiveness to a glucose challenge and that the IVGTT, using a dose of 0–5 g glucose/kg bodyweight, is a useful diagnostic procedure in dogs with insulinoma.     

Feline cystic rete ovarii

Cysts of the rete ovarii system from 20 cats are described. The cellular morphology of these cysts varies because the normal rete ovarii in the cat consists of three anatomically distinct parts. Cysts arise in the ovarian medulla or at the tubal extremity of the ovary, expand into ovarian stroma rather than the mesovarium , and are lined by ciliated columnar to flattened epithelium. Their functional significance is unknown.     

Analgesic effects of butorphanol in horses: dose-response studies

The analgesic effects of butorphanol (0.05, 0.1, 0.2, and 0.4 mg/kg), pentazocine (2.2 mg/kg), and butorphanol vehicle (0.04 ml/kg) were observed in 6 horses. These horses were instrumented to measure response objectively to painful superficial and visceral stimuli. The tested drugs were given IV according to a Latin square design. After preinjection base-line measurements were made, the analgesic effects were observed at 15 and 30 minutes and then at 30-minute intervals until postinjection minute 240. Analgesic effects of butorphanol were dose-related, with durations between 15 and 90 minutes. Duration of analgesia after pentazocine (2.2 mg/kg) was given was between 15 and 30 minutes. When compared with pentazocine, the 0.4 mg/kg dose of butorphanol provided a more intense and longer period of analgesia. A butorphanol dose of 0.2 mg/kg IV appears optimal. On a dose-body weight basis, the potency of butorphanol was 10 to 17 times that of pentazocine. Behavioral side effects were noted with both agents and were dose-related.     

Microtubular mass defect of spermatozoa in the stallion

A microtubular mass (MM) defect was found in the spermatozoa of 7 Standardbred stallions; 3 stallions were sons of the same sire. Two of these 3 stallions and 2 other stallions (for a total of 4 out of the 7 stallions) were considered subfertile when the defect was first observed. Fertility improved with time, either during the first breeding season or when a given stallion was used less frequently; however, the MM defect persisted, consisting of tortuous arrays of small abnormal microtubules visible only by transmission electron microscopy. The MM probably contained the protein tubulin as indicated by immunofluorescence. Microtubules of the MM were different from normal microtubules in being highly coiled, rather than straight, without interconnecting bridges or arms and had a 20% smaller cross-sectional diameter than did normal microtubules. Synthesis of the MM may occur near areas of the nuclear membranes normally associated with the manchette of the developing spermatid.     

Cardiopulmonary effects of halothane anesthesia in cats

The cardiopulmonary effects of 2 planes of halothane anesthesia (halothane end-tidal concentrations of 1.78% [light anesthesia] and 2.75% [deep anesthesia]) and 2 ventilatory modes (spontaneous ventilation [SV] or mechanically controlled ventilation [CV]) were studied in 8 cats. Anesthesia was induced and maintained with halothane in O2 only, and each cat was administered each treatment according to a Latin square design. Cardiac output, arterial blood pressure, pulmonary arterial pressure, heart rate, respiratory frequency, and PaO2, PaCO2, and pH were measured during each treatment. Stroke volume, cardiac index, and total peripheral resistance were calculated. A probability value of less than 5% was accepted as significant. In the cats, cardiac output, cardiac index, and stroke volume were reduced by deep anesthesia and CV, although only the reduction attributable to CV was significant. Systemic arterial pressure was significantly reduced by use of deep anesthesia and CV. Respiratory frequency was significantly lower during CV than during SV. Arterial PO2 was significantly decreased at the deeper plan of anesthesia, compared with the lighter plane. At the deeper plane of anesthesia, arterial PCO2 and pulmonary arterial pressure were significantly lower during CV than during SV. The deeper plane of halothane anesthesia depressed cardiopulmonary function in these cats, resulting in hypotension and considerable hypercapnia. Compared with SV, CV significantly reduced circulatory variables and should be used with care in cats. Arterial blood pressure was judged to be more useful for assessing anesthetic depth than was heart rate or respiratory frequency.     

Effects of prostaglandin F2 alpha on degranulation of bovine luteal cells on days 4 and 12 of the estrous cycle

Corpora lutea were collected from 18 beef heifers on day 4 or 12 of the estrous cycle, 1 hour after prostaglandin (PG) F2 alpha or saline (control) treatment. Five heifers also were treated with PGF2 alpha on day 4, but their corpora lutea were not collected until day 12. The relative percentage of cytoplasm occupied by granules decreased only in large luteal cells (LLC) in heifers given PGF2 alpha on day 12, compared with the percentage in controls. Small luteal cells (SLC) were not as affected. The luteal concentration of progesterone was similarly decreased only in heifers given PGF2 alpha on day 12. Treatment of heifers with PGF2 alpha on day 4 had no marked effect on progesterone values or on the relative percentage of cytoplasm occupied by granules in LLC or SLC. Seemingly, LLC were more responsive to PGF2 alpha than were SLC, and PGF2 alpha treatment of beef heifers at day 4 did not markedly impair luteal function.     

Lumbosacral epidural management.

Spinal techniques (epidural and subarachnoid injection) are taught in veterinary curricula, but because they are less convenient they are not used widely in practice. Many animals undergoing routine (below the umbilicus level) surgical procedures can be anesthetized with mild sedation and caudal epidural analgesia. Ninety minutes of analgesia is provided by the shorter-acting agents, whereas bupivacaine provides 4 to 6 hours. Twelve percent of our attempts failed to produce analgesia. Sedation, surgeon acceptance, and patient temperament contributed to an additional few failures. High-risk cases are better handled on oxygen.     

Feedtrough dirt as a source of Clostridium botulinum type C intoxication in a group of farm horses

Four horses from the same farm developed clinical signs of botulism during the winter months; three of these horses died. One horse survived an initial attack and recovered over a three-week period, but died during a second attack. The horse that survived took six weeks to recover. Clinical and postmortem examination ruled out other causes of disease. Confirmation of the diagnosis was made by isolation of Clostridium botulinum type C toxin from the dirt in the bottom of an oak feedtrough used by all horses, and from the colonic contents of one of the horses that died. To our knowledge, this is the second case of C. botulinum type C intoxication reported in horses in North America. In both cases, soil and sand near aquatic environments were identified as the source of toxin.