Effects of the opioid remifentanil on the arrhythmogenicity of epinephrine in halothane-anesthetized dogs

Opioids may exert a protective effect against ventricular arrhythmias via a vagally mediated mechanism. This study evaluated the effects of the opioid remifentanil on arrhythmogenicity of epinephrine during halothane anesthesia. Eight dogs were assigned to 2 treatments in a randomized crossover design, with 1-week intervals between treatments. Anesthesia was maintained with 1.3% end-tidal halothane in oxygen and mechanical ventilation to maintain eucapnia. A constant rate infusion of remifentanil (0.72 microg/kg/min) was administered throughout the study in the experimental treatment, while control animals received physiologic saline as placebo. The arrhythmogenic dose of epinephrine (ADE), defined as 4 premature ventricular complexes (PVCs) within 15 s, was determined by administering progressively increasing infusion rates of epinephrine (2.5, 5.0, and 10 microg/kg/min), allowing 20 min intervals between each infusion rate. In both treatments, epinephrine infusions induced bradyarrhythmias and atrioventricular conduction disturbances, which were followed by escape beats and PVCs. In the remifentanil treatment, mean +/- s ADE values (11.3 +/- 4.9 microg/kg) did not differ from values observed in control animals (9.9 +/- 6.1 microg/kg). On the basis of the ADE model for assessing the arrhythmogenity of drugs during halothane anesthesia, the present study did not demonstrate a protective effect of remifentanil (0.72 microg/kg/min) against ventricular arrhythmias in dogs.     

Hypertrophic gastropathy associated with gastric sarcoma in a dog

A 14-y-old spayed female Labrador Retriever was presented with an 8-mo history of chronic vomiting. Abdominal ultrasound and gastrointestinal endoscopy revealed a mass protruding into the gastric lumen, with cytologic features suggestive of sarcoma. A partial gastrectomy was performed; the gastric body and antrum were thickened, with a cerebriform appearance of the mucosal surface. Histologic examination revealed a submucosal neoplastic proliferation of fusiform cells variably arranged in irregular bundles and scattered whorls. Fusiform cells strongly reacted to antibodies against vimentin, S100, and neuron-specific enolase; glial fibrillary acidic protein was moderately and multifocally expressed. Pancytokeratin, KIT, α–smooth muscle actin, and desmin were nonreactive. Histologic and immunohistochemical findings suggested a diagnosis of gastric sarcoma with features referable to a non-GIST (gastrointestinal stromal tumor), non–smooth muscle NIMT (non-angiogenic, non-lymphogenic intestinal mesenchymal tumor). The overlying gastric mucosa was thickened by elongated and dilated gastric glands, predominantly lined by intensely periodic acid-Schiff–stained mucous cells. This altered mucosal architecture was suggestive of Ménétrier-like disease. Although this disease has been hypothesized to predispose to gastric adenocarcinoma in dogs, an association with gastric sarcoma has not been documented previously in the veterinary literature, to our knowledge.     

A monoclonal antibody against a canine CD45 homologue: analysis of tissue distribution, biochemical properties and in vitro immunological activity

This report describes the characterisation of a monoclonal antibody (mAb), AB6, which recognises specifically a cluster of canine leukocyte surface molecules. The immunogen used for obtaining the AB6 mAb was a lysate of canine peripheral blood mononuclear cells (PBMC). This novel mAb belongs to the IgG2a isotype, and reacted in Western blot with four different canine leukocyte glycoproteins with apparent molecular weights of 180, 190, 205 and 220 kDa. The AB6 mAb recognised the majority of canine peripheral blood leukocytes as determined by flow cytometry (97%). It also exhibited a broad reactivity pattern against lymphoid and myeloid cells, inhibited the proliferation of mitogen-stimulated canine PBMC and did not recognise human PBMC and murine splenocytes. The biochemical properties, cell and tissue specificity, and in vitro biological activity of the AB6 mAb indicate that it recognises a canine CD45 homologue. The mAb could become a valuable diagnostic and research tool for the evaluation of immune functions in dogs.     

Abnormal ocular pigment deposition and glaucoma in the dog

The combined occurrence of ocular pigment deposition and glaucoma has been described in Cairn Terriers. Recently, this condition was also observed in two other breeds: the Boxer (two cases) and the Labrador Retriever (one case). Six dogs were referred to the Ophthalmology section of the Department of Clinical Sciences of Companion Animals and to a private referral clinic because of glaucoma or blindness in one or both eyes. In five cases ophthalmic examination showed pigment depositions in the sclera around the entire circumference of the perilimbal zone. Eight enucleated eyes (four eyes of two Cairn Terriers, three eyes of two Boxers and one eye of a Labrador Retriever) were examined microscopically. All eyes showed the same findings: an extensive infiltration of large melanin-containing cells with an eccentric nucleus, located in the iris, ciliary body, retina, choroids and sclera. Transmission electron microscopy of two of the examined eyes revealed that the morphology of most of these cells was consistent with melanophages. While reports in the veterinary literature concerning this condition are limited the cells concerned have been described to be melanocytes. Further research is needed to conclusively identify the cell type. As described in the present report, the histologic and transmission electron microscopic findings suggest a different etiology of the ocular pigment deposition and glaucoma compared with the pigment dispersal syndrome in humans.     

Midazolam,as a co‐induction agent,has propofol sparing effects but also decreases systolic blood pressure in healthy dogs

ObjectiveTo evaluate the effects of the co-administration of midazolam on the dose requirement for propofol anesthesia induction, heart rate (HR), systolic arterial pressure (SAP) and the incidence of excitement.Study designProspective, randomized, controlled and blinded clinical study, with owner consent.AnimalsSeventeen healthy, client owned dogs weighing 28 ± 18 kg and aged 4.9 ± 3.9 years old.MethodsDogs were sedated with acepromazine 0.025 mg kg^?1 and morphine 0.25 mg kg^?1 intramuscularly (IM), 30 minutes prior to induction of anesthesia. Patients were randomly allocated to receive midazolam (MP; 0.2 mg kg^?1) or sterile normal saline (CP; 0.04 mL kg^?1) intravenously (IV) over 15 seconds. Propofol was administered IV immediately following test drug and delivered at 3 mg kg^?1 minute^?1 until intubation was possible. Scoring of pre-induction sedation, ease of intubation, quality of induction, and presence or absence of excitement following co-induction agent, was recorded. HR, SAP and respiratory rate (f_R) were obtained immediately prior to, immediately following, and 5 minutes following induction of anesthesia.ResultsThere were no significant differences between groups with regard to weight, age, gender, or sedation. Excitement occurred in 5/9 dogs following midazolam administration, with none noted in the control group. The dose of propofol administered to the midazolam group was significantly less than in the control group. Differences in HR were not significant between groups. SAP was significantly lower in the midazolam group compared with baseline values 5 minutes after its administration. However, values remained clinically acceptable.Conclusions and clinical relevanceThe co-administration of midazolam with propofol decreased the total dose of propofol needed for induction of anesthesia in sedated healthy dogs, caused some excitement and a clinically unimportant decrease in SAP.     

Effect of food on the pharmacokinetics of oral cefuroxime axetil in dogs

Cefuroxime axetil pharmacokinetic profile was investigated in 12 Beagle dogs after single intravenous and oral administration of tablets or suspension at a dose of 20 mg/kg, under both fasting and fed conditions. A three-period, three-treatment crossover study (IV, PO under fasting and fed condition) was applied. Blood samples were withdrawn at predetermined times over a 12-hr period. Cefuroxime plasma concentrations were determined by HPLC. Data were analyzed by compartmental analysis. No statistically significant differences were observed between formulations and feeding conditions on PK parameters. Independently of the feeding condition, absorption of cefuroxime axetil after tablet administration was low and erratic. The drug has been quantified in plasma in 3 out of 6 and 5 out of 6 dogs in the fasted and fed groups. For this formulation, the bioavailability (F), peak plasma concentration (C_max), and area under the concentration–time curve (AUC) of cefuroxime axetil were significantly enhanced (p < .05) by the concomitant ingestion of food (32.97 ± 13.47–14.08 ± 7.79%, 6.30 ± 2.62–2.74 ± 0.66 µg/ml, and 15.75 ± 3.98–7.82 ± 2.76 µg.hr/ml for F, C_max, and AUC in fed and fasted dogs, respectively), while for cefuroxime axetil suspension, feeding conditions affected only the rate of absorption, as reflected by the significantly shorter absorption half-life (T_½(a)) and time to peak concentration (T_max) (0.55 ± 0.27–1.15 ± 0.19 hr and 1.21 ± 0.22–1.70 ± 0.30 for T_½(a) and T_max in fed and fasted dogs, respectively). For cefuroxime axetil tablets, T > MIC (≤1 µg/ml) was <2 hr in fasted and ≈4 hr in fed animals, and for cefuroxime axetil suspension, T > MIC (≤1 µg/ml) was ≈5 hr and for T >MIC (≤4 µg/ml) was ≈2.5 hr for fasted and fed dogs, respectively. Cefuroxime axetil as a suspension formulation seems to be a better option than tablets. However, its short permanence in plasma could reduce its clinical usefulness in dogs.     

Canine fertility: The consequences of selection for special traits

Pedigree dogs and cats are bred aiming to conform breed standards with very poor consideration for breeding stock fertility. At the same time, the genetic asset underlining reproductive traits could be effectively analysed like in other species under selection. The definition of selection targets is very important in breeding protocols determination. The aim of the present work is to present an overview of the different correlations between reproduction and genetics, starting from selection procedure and inbreeding coefficient moving to genomic and the application of SNPs and GWAS on population study and identification of genes involved in phenotypical variation of reproductive traits in dogs. Particular relevance has been given to the concept of inbreeding which effects on canine reproduction have been presented. The use of genomic information in inbreeding coefficient calculation can be considered an improved effective procedure in the evaluation of the genetic variability loss in canine population and its negative effects on reproductive traits.     

Type IV secretion and Brucella virulence

The type IV secretion system, encoded by the virB region, is a key virulence factor for Brucella. The 12 genes of the region form an operon that is specifically induced by phagosome acidification in cells after phagocytosis. We speculate that the system serves to secrete unknown effector molecules, which allow Brucella to pervert the host cell endosomal pathways and to create a novel intracellular compartment in which it can replicate.