Elizabeth Munro

Migrating foreign body in the parotid duct of a boxer dog

FOREIGN body migration is not an uncommon syndrome in dogs, and clinical outcomes range from small, cutaneous inflammatory reactions to severe inflammation and bacterial infection of body cavities, organs or both ([Brennan and Ihrke 1983][1], [White and Lane 1988][2]). Most foreign bodies are grass

Advances in ocular therapeutics in dogs and cats

A RANGE of agents with diverse actions is used in ocular therapeutics, including antimicrobials, anti-inflammatory agents, tear replacement preparations, immunosuppressants, ocular hypotensive agents and modulators of pupil size. The cornerstone of successful ophthalmology, however, is accurate diagnosis, which is based on careful and critical examination of the eye. This article provides practical information about the more recently available products, and considers their use in context with established practice.

A quadrigeminal dermoid cyst with concurrent necrotizing granulomatous leukoencephalomyelitis in a Yorkshire Terrier dog

A 2-year-old female Yorkshire Terrier dog presented with neurological deficits. Magnetic resonance imaging revealed an 8 mm in diameter mass centered left of midline arising from the quadrigeminal cistern, with a fatty or proteinaceous content. A further fat signal intensity focus was present in the tip of the temporal horn of the right lateral ventricle, in keeping with a “floating” fat embolus within the cerebrospinal fluid. A ruptured dermoid cyst was diagnosed. Within the frontal lobe on both sides were ill-defined and extensive high T2 signal areas, with mass effect within the white matter, and asymmetrical contrast enhancement following intravenous injection of gadolinium. Postmortem gross and histological examination confirmed the mass in the quadrigeminal cistern to be a dermoid cyst. In addition, severe multifocal necrotizing granulomatous leukoencephalomyelitis was found in the corona radiata and spinal cord. The relationship between these 2 pathologies is discussed.

Testosterone release in intact male dogs following the injection of a GnRH analogue

RELEASE of gonadal testosterone in the normal male dog is mediated via luteinising hormone (LH) released by the pituitary gland in response to gonadotrophin releasing hormone (GnRH). The effects of buserelin, a GnRH analogue (D-Ser [But]6 Des Gly-NH2 10 GnRH ethylamide [Receptal; Hoechst]) on testosterone levels was investigated in order to establish whether this analogue could be used in provocative stimulation of the pituitary-gonadal axis as a clinical test. Such a test might be of value in the investigation of suspected cases of sex hormone-related and growth hormone-responsive alopecia. These uncommon canine endocrine dermatoses both present as bilaterally symmetrical alopecia and, while they can be reliably distinguished from hypothyroidism and hyperadrenocorticalism, it is not always possible to distinguish them from each other. Abnormal responsiveness to GnRH might suggest that the disorder was sex hormone-related. The diagnostic work-up of suspected cases of growth hormone-responsive alopecia may include determination of the growth hormone levels after injection of an a-adrenergic agonist some affected dogs show a complete or partial lack of response. However, it is important to rule out other endocrine dermatoses before performing this test as hypothyroidism, hyperadrenocorticism and sex hormone imbalances can affect the result (Schmeitzel 1990). An abnormal response to GnRH would indicate that growth hormone levels should be interpreted with caution. Six healthy intact male beagles aged from 18 months to three years, weighing 13 to 19 kg, with a normal ultrasonographic appearance of the testes and prostate gland, were chosen for the study. Buserelin was injected into the cephalic vein of each dog on three occasions separated by four-week intervals, the dose of buserelin varying on each occasion. Dosages of 0-1, 0.2 and 0-5 ,ug buserelin/kg bodyweight were given, and serum testosterone levels were monitored by jugular venous sampling at 20, 40, 60 and 90 minutes after injection. As basal testosterone levels have been shown to fluctuate markedly throughout a 24-hour period (De Palatis and others 1978), jugular venous blood was also withdrawn at 20-minute intervals over the 80-minute period preceding the injection of buserelin. The samples were collected into plain glass tubes and allowed to clot at room temperature before centrifugation. Serum was then withdrawn and stored at -40°C in plain glass tubes until the samples were assayed. Testosterone levels were measured using a solid-phase 1251 radioimmunoassay (Coat-A-Count Total Testosterone; Diagnostic Products). A standard curve was derived from serial dilutions of testosterone (Sigma Chemical Company) in serum from a castrated dog. All the samples were assayed on a single occasion, with an intra-assay coefficient of variation (calculated from 20 duplicated samples) of 5-4 per cent. The results demonstrated marked fluctuations in the resting level of testosterone, as previously reported (De Palatis and others 1978), but after an injection with buserelin an overall pattern was seen to emerge with an increase in testosterone levels reaching a peak at 40 to 60 minutes (Fig 1). This finding is in keeping with results from a previous study (Jones and others 1976) in which Dogl Dog 4