Evaluation of the long-acting somatostatin analogue Octreotide in the management of insulinoma in three dogs

The response of dogs with insulinoma to surgical and medical management is variable, with the majority developing intractable hypoglycaemia. A long-acting somatostatin analogue, Octreotide (SMS 201–995; Sandostatin) has been useful in the management of hypoglycaemia in humans with insulinoma, and preliminary reports suggest a beneficial clinical response in dogs with insulinoma. The present study objectively evaluated Octreotide in the management of three dogs with immunohistochemically confirmed insulinoma. Octreotide had no benefit over placebo, and little effect on circulating glucose and insulin concentrations despite clearly detectable plasma concentrations of Octreotide. No clinical improvement was apparent in two dogs given Octreotide over a period of two and three weeks. These results contrast with the positive clinical responses noted previously and indicate that further placebo controlled, objective studies are necessary before clear statements on the treatment of insulinoma with Octreotide are made.     

Helicobacter infection in dogs and cats: facts and fiction

The discovery of the spiral bacterium Helicobacter pylori and its causative role in gastric disease in humans has brought a dramatic change to gastroenterology. Although spiral bacteria have been known for more than a century to infect the stomachs of dogs and cats, recent research has been conducted mainly in the wake of interest in H. pylori. H. pylori has not been found in dogs and only very rarely in cats and zoonotic risk is minimal. A variety of other Helicobacter spp. can infect the stomach of pets; however, their pathogenic role is far from clear, and they have a small but real zoonotic potential. The prevalence of gastric Helicobacter spp. in dogs and cats is high, irrespective of clinical signs, and as in human medicine, mode of transmission is unclear. The relationship of Helicobacter spp. to gastric inflammation in cats and dogs is unresolved, with inflammation, glandular degeneration, and lymphoid follicle hyperplasia accompanying infection in some but not all subjects. Circulating anti-Helicobacter immunoglobulin G antibodies have been detected in 80% of dogs with naturally acquired infection and most dogs and cats with experimental infection. The gastric secretory axis is similar in infected and uninfected cats and dogs and no relationship of infection to gastrointestinal ulcers has been found. Differences in the pathogenicity of Helicobacter spp. are apparent, because infection with H pylori is associated with a more severe gastritis than infection with other Helicobacter spp. in both cats and dogs. Rapid urease test, histopathology, and touch cytology are all highly accurate invasive diagnostic tests for gastric Helicobacter-like organisms in dogs and cats, whereas culture and polymerase chain reaction are the only means to identify them to the species level. Urea breath and blood tests or serology can be used to diagnose Helicobacter spp. noninvasively in dogs and cats. Most therapeutic studies in pets have not shown long-term eradication of Helicobacter spp. Whether this is due to reinfection or recrudescence has not been established.     

Effect of tilmicosin on chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages

OBJECTIVE: To evaluate chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages (AM) exposed to tilmicosin. ANIMALS: 12 healthy calves and 12 healthy pigs. PROCEDURES: Lungs were obtained immediately after euthanasia; AM were collected by means of bronchoalveolar lavage and density gradient centrifugation. Chemotactic activity was evaluated by exposing AM to lipopolysaccharide or macrophage inhibitory peptide during incubation with tilmicosin. Phagocytic activity was evaluated by incubating AM with tilmicosin for 24 hours and then with tilmicosin-resistant Salmonella serotype Typhimurium. Bactericidal activity was evaluated by incubating AM with tilmicosin (0, 10, or 20 microg/ml for bovine AM; 0 or 10 microg/ml or 10 microg/ml but washed free of tilmicosin for porcine AM) and then with Mannheimia haemolytica (bovine AM) or with Actinobacillus pleuropneumoniae or Pasteurella multocida (porcine AM). RESULTS: Tilmicosin had no significant effects on chemotactic or phagocytic activities of bovine or porcine AM. The time-course of bactericidal activity was best described by polynomial equations. Time to cessation of bacterial growth and area under the time versus bacterial number curve were significantly affected by incubation of AM with tilmicosin. CONCLUSIONS AND CLINICAL RELEVANCE: Results show that bactericidal activity of bovine and porcine AM was enhanced by tilmicosin, but not in proportion to the reported ability of AM to concentrate tilmicosin intracellularly. With or without exposure to tilmicosin, the time-course of bactericidal activity of bovine AM against M haemolytica and of porcine AM against A pleuropneumoniae or P multocida was too complex to be reduced to a simple linear equation.     

COLOR DOPPLER AND DOPPLER SPECTRAL ANALYSIS IN THE SPINAL CORD OF NORMAL DOGS

Doppler ultrasonography of the spinal cord was performed in 34 normal, anesthetized dogs following hemilaminectomy. This study was part of an investigation to evaluate the efficacy of a 21-aminosteroid compound and high dose methylprednisolone for the treatment of spinal cord trauma. Grey-scale images of the canine spinal cord were similar to those described for the spinal cord of people. Doppler waveforms of intraparenchymal spinal arteries exhibited high end diastolic blood flow velocities, indicating low resistance to flow. Doppler values (mean ± SD) for arteries immediately ventrolateral to the central canal were: Peak Systolic Velocity = 5.78 ± 2.5 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Systolic/Diastolic ratio = 169 ± 0.19, Pulsatility Index = 0.53 ± 0.09, and Resistance Index = 0.4 ± 0.06.     

Changes in physical condition and ejaculate characteristics in paddock-mated rams.

Eight Merino rams were joined for 8 weeks to 400 Merino ewes in a 31 ha paddock during April–June. Six of the rams were monitored for body weight, body condition, testicular volume and semen characteristics before, during and after the joining period. The day before joining, at 2-weekly intervals through joining, and 2 weeks after the end of the joining period 6 collections were made from each ram using an artificial vagina. The semen was evaluated for volume, density, wave motion and morphology. Body weight and condition and testicular volume of the rams increased prior to joining. Body weight and condition decreased markedly until the sixth week of the mating period, after which there was some recovery. Testicular volume, on the other hand, declined steadily through the mating period and showed no recovery during the post-mating period. Amongst the semen characteristics, ejaculate volume, wave motion score, sperm density and percentage of live sperm all fell significantly during the first 2 weeks of mating but there was a steady recovery through the remainder of the mating period and in the 2 weeks after ram removal. The percentage of abnormal sperm increased significantly throughout the joining period but showed a slight decline in the post-mating period. The results emphasise the extent of the decline in ejaculate characters, and to a lesser extent, in physical characters which can occur during the first cycle of joining in paddock-mated rams.     

Acute experimentally induced aflatoxicosis in the weanling pony

Nineteen weanling ponies and 1 adult pony were given a single oral dose of aflatoxin B1 (AFB1). Dosages were: 0, 0.5, 1, 2, 4, 5, 6, and 7.4 mg of AFB1/kg of body weight. Vital signs were monitored, and whole blood and serum collected for analysis of serum enzymes, prothrombin time, blood cell counts, and serum urea nitrogen. Ponies that died were examined for gross lesions, and tissues were collected for histopathologic examination and analysis of AFB1 and AFM1 residues. Two of the 4 ponies given the 2 mg/kg dose and all ponies given the larger dosages died within 76 hours. Clinical signs included increased rectal temperature, faster heart and respiratory rates, abdominal straining, bloody feces, and tetanic convulsions. At necropsy, ponies that died of acute aflatoxicosis showed visceral petechiae and hepatic focal lesions. Histopathologic changes included severe hepatic necrosis, vacuolation, and bile duct hyperplasia. Aflatoxins B1 and M1 were recovered from liver, kidney, skeletal muscle, and gastrointestinal contents. One other pony given the 2 mg/kg dose died 32 days after dosing, and 1 control pony died after 70 days. Continuous elevations in prothrombin time and serum aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transpeptidase levels were observed in ponies dosed at 4 mg/kg or more. Significant (P less than 0.05) elevations in these values, which peaked 2 to 3 days after dosing, were seen in ponies given the 2 mg/kg dose. This group also had significant increases over controls in PCV and hemoglobin concentration 5 days after dosing.     

Aortic atherosclerosis in nonlaying hens with fatty liver syndrome

Ten laying hens with low plasma cholesterol levels and no signs of fatty liver syndrome were examined at necropsy. Liver coloration and deposition of body fat were not abnormal in such hens. Eleven nonlaying hens had signs of fatty liver syndrome. They were out of production for 1 to 3 months and had elevate plasma cholesterol levels. At necropsy, such hens had yellow livers, heavy deposits of body fat, and several involuted egg yolks, which were dark yellow. Intimal plaques were observed by light microscopy in the abdominal aortas of hens with low plasma cholesterol levels; the plaques contained little or no lipid and were composed of three or four rows of modified smooth-muscle cells. Aortic intimal plaques of hens with high plasma cholesterol levels were composed of 16 to 18 rows of modified smooth-muscle cells when examined by light microscopy. The plaques contained intracellular and extracellular lipid, indicating aortic atherosclerosis. Electron-microscopic observations of the abdominal aortas of both groups of hens were similar to light-microscopic observations, except that lipid, including cholesterol clefts, was seen both intracellularly and extracellularly in the thickened tunica intima of hens with high plasma cholesterol values. Thus, the presence of aortic atherosclerosis was confirmed by electron microscopy. It is suggested that the endogenous hypercholesterolemia and cessation of egg production, characteristic of severe fatty liver syndrome, originated from the reabsorption of involuted egg yolks and that such reabsorption caused the development of aortic atherosclerosis and deposition of excess body fat.     

Angiostroneylosis in Cornwall: Clinical presentations of eight cases

Clinical signs in eight dogs with Angiostrongylus vasorum infection included chronic cough, dyspnoea, lumbar pain, hindleg paresis/paralysis, abdominal pain, weakness and collapse; two of the dogs were asymptomatic. Thrombocytopenia was present in two dogs and a mild anaemia in one. Thoracic radiographs showed mild right heart enlargement in two out of three dogs and a pneumothorax in one. At post mortem examination in three dogs, the lungs were swollen with a mottled appearance and there was dilatation of the right ventricle. Adult A vasorum were found in the right heart, the pulmonary artery and its branches. Adult worms were also found in the systemic vasculature in one dog, associated with thromboembolism. Treatment with ivermectin in two dogs and fenbendazole in three dogs resulted in the resolution of clinical signs and no demonstrable larvae in the faeces one to two weeks later.