Use of phenytoin to treat digitalis-induced cardiac arrhythmias in a miniature Shetland pony

Two miniature Shetland ponies showing clinical signs of Digitalis purpurea (foxglove) poisoning were examined. One animal died shortly afterwards, but the second was treated successfully with the anti-arrhythmic agent, phenytoin, and was discharged after 16 days.     

Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization

The capacitation process of sperm cells involves complex changes in the composition and orientation of molecules at the surface of the sperm cell. Here we focus on the lipid architecture in the sperm plasma membrane and demonstrate that the sperm plasma membrane is not static but is an extremely dynamic structure. Advanced fluoroscopic techniques enabled continuous monitoring of lipid organization in living cells and extremely rapid lipid movements were observed. The orientation of lipids in the sperm plasma membrane changed under capacitative treatments, was found to be sensitive for temperature and also changed upon binding of sperm cells to the zona pellucida. The changes in membrane properties coincided with an activation of protein kinases resulting in tyrosine phosphorylation of specific plasma membrane proteins. The detected membrane changes relate to intrinsic membrane properties such as fluidity, permeability, adhesiveness and fusibility. We think that these results may provide a physiological basis for new assays, able to discriminate between functional and non-physiological sperm cells.     

Tepoxalin reduces pruritus and modified CADESI-01 scores in dogs with atopic dermatitis: a prospective, randomized, double-blinded, placebo-controlled, cross-over study

Thirty dogs with atopic dermatitis were given tepoxalin (Zubrin®, Intervet/Schering-Plough Animal Health, Boxmeer, the Netherlands) or placebo once daily for 4 weeks, followed by a wash-out period of 1 week before reversing the treatments. Pruritus was scored by the owners using the Edinburgh Pruritus Scale and one investigator employed a modification of the Canine Atopic Dermatitis Extent and Severity Index-01 (mCADESI-01) to score the physical lesions. After administration of tepoxalin there was a ≥ 50% reduction in pruritus and mCADESI-01 scores in 36% and 25% of the dogs, respectively, whereas following administration of the placebo there was a ≥ 50% reduction in pruritus and mCADESI-01 scores in only 25% and 16% of the dogs, respectively. Analysis of pooled data indicated that tepoxalin resulted in a significant reduction in pruritus ( P  = 0.012) and mCADESI-01 ( P  = 0.002) scores but there was no significant change after placebo. The median pruritus scores before and after tepoxalin were 2 (range 1–5) and 1 (range 0–5), respectively, and before and after placebo were 2 (range 0–4) and 2 (range 0–4), respectively. The median mCADESI scores before and after tepoxalin were 23 (range 0–68) and 16 (range 0–72), respectively, and before and after placebo were 18 (range 3–79) and 24 (range 0–65), respectively. At the dose used in this study (10.0–19.1 mg kg⁻¹), tepoxalin was well-tolerated and no adverse effects were noted.     

Regulation of atrial fibrillation in horses with oral quinidine sulfate. Discussion of the disease picture in a typical case

Atrial fibrillation is a disorder of cardiac rhythmicity, and its importance in the horse depends on the underlying cause and the function of the horse. Before the decision is taken to start treatment, it has first to be ascertained whether treatment is worthwhile and whether the horse is an appropriate candidate for treatment. This article gives a short overview of current opinion on the cause and treatment of atrial fibrillation in the horse. The most used treatment at the moment, oral chinidine sulphate, is discussed. The hemodynamic consequences of atrial fibrillation and the response of a patient to treatment with chinidine sulphate are also discussed.     

Infection of a canine macrophage cell line with leishmania infantum: determination of nitric oxide production and anti-leishmanial activity

We have previously shown that resistance to Leishmania infantum in dogs is associated with a Th1 type of immune response. In this study, we use a canine macrophage cell line (030-D) that can readily be infected with this protozoan parasite. Our aim is to further characterize the effector mechanisms involved in killing of Leishmania parasite in dogs. We observed that activation of 030-D cells by incubation with a supernatant derived from a Leishmania-specific T cell line containing IFN-gamma, TNF-alpha and interleukin-2 (IL-2) resulted in enhanced nitric oxide (NO) production by these cells. In addition, we observed enhanced anti-leishmanial activity of infected 030-cells after activation. Both, NO production and anti-leishmanial activity were abrogated by addition of L-N(G)-nitroargininemethyl ester (L-NAME), an analogue of L-arginine. Thus, NO play an important role in the anti-leishmanial activity of these canine macrophages. We propose the infection of the 030-D cell line as a good in vitro model to further investigate parasite-host cell interactions in dogs, a natural host of Leishmania parasites.     

The Effect of Sedation on Gastric Emptying of a Liquid Marker in Ponies

OBJECTIVE: The effect of sedation on gastric emptying was evaluated in six ponies by monitoring serum concentrations of acetaminophen (AP) after intragastric administration. EXPERIMENTAL DESIGN: Prospective randomized experimental study. ANIMALS: Six adult ponies, 135 to 275 kg. METHODS: Fifteen minutes after the intravenous administration of xylazine (1 mg/kg), butorphanol (0.05 mg/kg), acepromazine (0.05 mg/kg) or saline, ponies were given AP (20 mg/kg in 350 mL water) by stomach tube. Blood for AP analysis was collected at baseline and 15, 30, 45, 75, 90, 105, and 120 minutes after AP administration. The time (Tmax) to reach peak serum concentration (Cmax), and the area under the AP serum concentration versus time curve (AUC) were determined for each treatment group. RESULTS: Tmax was 31 mins in the control group, and this increased significantly (P<.05) after sedation. Cmax decreased (P<.05) after xylazine administration, and AUC decreased (P<.05) after acepromazine. CONCLUSIONS: This study indicated that sedation has a significant effect on the gastric emptying rate of a liquid in ponies.     

Thymic hyperplasia causing right ventricular outflow tract compression following treatment for oesophageal rupture in an Arabian colt

True thymic hyperplasia has been reported sporadically in the human literature as an immunological rebound phenomenon following immunosuppressive treatment or disease. There are limited accounts in domestic species, mainly following vaccination, and thymic hyperplasia has not been a recognised condition in the horse to date. This report details a case of true thymic hyperplasia in a 10-week-old Arabian colt diagnosed by histopathology of core biopsy samples. The colt developed pulmonary stenosis caused by compression due to a space occupying lesion in the cranial mediastinum following a 3-month history of hospitalisation for treatment of traumatic oesophageal rupture with perioesophageal abscess formation. Diagnostic imaging of the cranial mediastinum was indicative of a thymic mass, and histopathology confirmed the mass was normal (hyperplastic) thymic tissue. The colt was treated with a tapering dose of corticosteroids, which led to involution of the hyperplastic tissue and resolution of pulmonary artery compression. Thymic hyperplasia may be an unrecognised sequela to chronic inflammation in horses and was only identified in this case when the size was sufficient to compress right cardiac outflow.     

Leukoencephalomalacia in a horse induced by fumonisin B1 isolated from Fusarium moniliforme

Each of two horses was dosed by stomach tube with culture material on maize of Fusarium moniliforme MRC 826. One horse developed severe hepatosis and mild oedema of the brain after 6 doses of 2.5 g of culture material/kg body mass/day in 7 days. The second horse, in a similar experiment but at a dosage rate of 1.25 g/kg/day, developed mild hepatosis and moderate oedema of the brain. In both animals the brain oedema was particularly noticeable in the medulla oblongata. The mycotoxin fumonisin B1 was extracted and purified from the culture material of F. moniliforme MRC, 826 which contained approximately 1 g/kg of this compound. A horse was injected intravenously 7 times from Day 0-Day 9 with 0.125 mg of fumonisin B1/kg body mass/day. Clinical signs of neurotoxicosis, which appeared on Day 8, included nervousness followed by apathy, a wide-based stance, trembling, ataxia, reluctance to move, paresis of the lower lip and tongue, and an inability to eat or drink. Euthanasia was performed on the horse on Day 10 while the animal was in a tetanic convulsion. The principal lesions were severe oedema of the brain and early, bilaterally symmetrical, focal necrosis in the medulla oblongata. This report provides experimental evidence that fumonisin B1, produced by F. moniliforme, causes equine leukoencephalomalacia.