Ultrasonographic evaluation of the effects of azithromycin on antral motility and gastric emptying in healthy cats

BackgroundErythromycin, a macrolide antibiotic with motilin agonist properties, shortens gastric emptying (GE) time in healthy cats. Azithromycin, another macrolide antibiotic, is effective for treatment of gastric paresis in people.ObjectivesTo evaluate the effects of azithromycin on GE and gastric motility in healthy cats in comparison with erythromycin (positive control) and placebo.AnimalsEight healthy purpose‐bred cats.MethodsProspective, blinded, crossover study. Cats received either azithromycin (3.5 mg/kg PO q24h), erythromycin (1 mg/kg PO q8h), or placebo for 24 hours before and during evaluation of GE. A validated method using ultrasound for sequential measurements of antral area as well as amplitude and frequency of contractions was used to assess GE and evaluate gastric antral motility postprandially over an 8‐hour period.ResultsGE was significantly faster (P < .05) after administration of azithromycin and erythromycin when compared to placebo in the late phase of fractional emptying from 75% (mean ± SD: 327 ± 51 minutes, 327 ± 22 minutes, and 367 ± 29 minutes, respectively), to 95% fractional emptying (399 ± 52 minutes, 404 ± 11 minutes, and 444 ± 24 minutes, respectively). The drugs had no significant effect on antral motility variables at any time point.Conclusions and Clinical ImportanceAzithromycin and erythromycin shorten GE time in a comparable manner in healthy cats. Evaluation of their efficacy in cats with gastric dysmotility is warranted.     

Electrodiagnostic evaluation in feline hypertrophic muscular dystrophy

Standard needle electromyography (EMG) of 56 muscles and nerve conduction velocities (NCV) of the ulnar and common peroneal nerves were investigated in each of six cats affected with hypertrophic feline muscular dystrophy, 10 related heterozygote carriers and 10 normal cats. The EMG findings were considered normal in carrier and control cats, and consisted of 33% normal readings, 22% myotonic discharges, 18% fibrillation potentials, 11% prolonged insertional potentials, 10% complex repetitive discharges and 6% positive sharp waves in affected cats. Muscles of the proximal limbs were most frequently affected. No differences in NCV were found between the three cat groups. It was concluded that dystrophin-deficient dystrophic cats have widespread and frequent EMG changes, predominantly myotonic discharges and fibrillation potentials, which are most pronounced in the proximal appendicular muscles.     

Abundance of mRNA of growth hormone receptor and insulin-like growth factors-1 and -2 in duodenal and colonic biopsies of dogs with chronic enteropathies*

Repair processes of the inflamed intestine are very important for dissolution of chronic enteropathies (CE). Therefore, we examined the mRNA abundance of growth hormone receptor (GHR), insulin-like growth factors (IGF)-1 and -2 in duodenal and colonic biopsies of dogs with CE such as food-responsive diarrhoea (FRD) and inflammatory bowel disease (IBD) before and after treatment as compared with each other and healthy dogs. A clinical score (Canine IBD Activity Index = CIBDAI) was applied to judge the severity of CE. Biopsies of duodenum and colon from client-owned dogs with CE were sampled before (FRD(bef), n = 5; IBD(bef), n = 5) and after treatment (FRD(aft), n = 5; IBD(aft), n = 5). Intestinal control samples were available from a homogenous control population (n = 15; C). Intestinal samples were homogenized, total RNA was extracted, reverse transcribed and analysed by real-time polymerase chain reaction to measure mRNA levels of GHR, IGF-1 and IGF-2. Results were normalized with glyceraldehyde phosphate dehydrogenase as housekeeping gene. The CIBDAI decreased during the treatment period in FRD and IBD (P < 0.01). In duodenum, GHR mRNA levels were higher in all groups than in C (P < 0.001). Duodenal IGF-1 mRNA levels in FRD(aft) and IBD(aft) tended to be higher than in C (P < 0.1). The IGF-2 mRNA abundance in FRD(aft) was higher than in C (P < 0.05) in duodenum. In colon, mRNA levels of IGF-1 in IBD(aft) were higher than in FRD(aft) (P < 0.05) and levels differed between IBD(aft) and C (P < 0.05). In conclusion, mRNA levels of GHR, IGF-1 and IGF-2 in the gastrointestinal tract were increased during CE when compared with gastrointestinally healthy dogs. The data suggest that GHR, IGF-1 and IGF-2 are involved in gastrointestinal repair processes.     

Performing both lateral abdominal radiographs may not improve the visualization of gas in the gastric outflow tract of cats

Reports in the veterinary literature support three‐view abdominal radiographs as a standard of practice for evaluating dogs with suspected gastrointestinal (GI) diseases. The usefulness of three‐view abdominal studies has not been evaluated in cats. Images from a prospective crossover group study with 20 healthy cats, and those from a retrospective cohort study of 110 cats, were reviewed and the location and degree of gas was assessed in the gastric outflow tract. Comparisons of the frequency of luminal gas were made between the views and between cats with GI disease versus cats without and between cats having sedation versus those without. Chi‐Square analysis was performed with P < .05 being considered significant. No significant difference was found in the location and degree of luminal gas in left versus right lateral views in all cats regardless of the order in which the views were obtained or in cats with GI disease versus cats without. Cats with gastric dilation had a higher overall frequency of gas; those with dilation with homogeneous material were higher than those with dilation with heterogeneous material. A higher frequency of gas was found in sedated cats than nonsedated, but further study is needed to determine the underlying cause. Based on these findings, a three‐view abdominal study for cats as a standard of practice may not be necessary, but obtaining the additional lateral view when gastric dilation is present might allow better visualization of the pyloric antrum and duodenum.     

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions

OBJECTIVE: To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy. METHODS: Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs. RESULTS: When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs. CLINICAL SIGNIFICANCE: The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.     

Cloning and expression of the gene encoding the major surface protein 5 (MSP5) of Anaplasma phagocytophilum and potential application for serodiagnosis

BACKGROUND: Anaplasma phagocytophilum (formerly known as the human granulocytic ehrlichia, Ehrlichia equi and Ehrlichia phagocytophila) is an obligate intracellular organism causing clinical disease in humans and various species of domestic animals. OBJECTIVES: The objectives of this investigation were to sequence and clone the major surface protein 5 (MSP5) of A phagocytophilum and to evaluate the suitability of this antigen in the serologic diagnosis of anaplasmosis in humans and dogs. METHODS: The msp5 gene of A phagocytophilum was sequenced, cloned, and expressed in Escherichia coli. The predicted amino acid sequence homology of the various MSP5/major antigenic protein 2 orthologs was compared among various Anaplasma and Ehrlichia species. Recombinant MSP5 of A phagocytophilum was used in an ELISA to detect antibodies in serum samples from humans and dogs infected with the organism. RESULTS: Serum samples from 104 individuals previously diagnosed with A phagocytophilum infection, as well as samples from clinically healthy humans, were tested. In addition, multiple samples from 4 dogs experimentally infected with 2 different geographic isolates of A phagocytophilum and 5 dogs naturally infected with a Swiss isolate were tested using ELISA. Using this group of immunofluorescent antibody test-positive and immunofluorescent antibody test-negative samples, we found the overall agreement between assays to be >90%. CONCLUSIONS: These results indicate that recombinant MSP5 has potential for use as a diagnostic test antigen to detect infection with A phagocytophilum in both dogs and humans. However, sequence similarities among orthologs of MSP5 in related species of anaplasma and ehrlichia suggest that cross-reactivity among these pathogens is likely if the entire peptide is used as a test antigen.     

ENDOSCOPIC ULTRASONOGRAPHY FOR THE DIAGNOSIS OF INTRATHORACIC LESIONS IN TWO DOGS

Endoscopic ultrasound was developed initially in humans to overcome limitations of conventional ultrasound in examining certain internal organs due to intervening bone or air-filled structures. Endoscopic ultrasound has been used most widely in investigation of the gastrointestinal tract in humans, but many intrathoracic applications as well as endoscopic ultrasound-guided techniques have recently been described. Mediastinal and pulmonary structures can be examined with endoscopic ultrasound since a high frequency ultrasound probe can be brought into close contact with the areas of interest via a transesophageal approach. The purpose of this report is to describe the application of endoscopic ultrasound as an aid in the diagnosis of intrathoracic disease in the dog. Two dogs, one with a history of prior esophageal foreign body extraction, the other with apathy, weakness and dyspnea were referred for further investigation. Both dogs had caudal intrathoracic soft tissue opacities diagnosed radiographically, but their origin and nature were difficult to determine. Conventional ultrasound was limiting in both dogs due to their location and superimposition of gas-filled structures. With endosonography lesions were characterized more completely. We have found endoscopic ultrasound to be an elegant diagnostic tool for the investigation of radiographically detected intrathoracic lesions in the dog whose origins are difficult to determine or do not lend themselves to investigation by conventional ultrasound. Endoscopic ultrasound provides valuable diagnostic information complementary to that provided radiographically which aids in therapeutic planning. Endoscopic ultrasound was also more sensitive for detecting mediastinal lymphadenomegaly than radiography in one of the dogs. An additional advantage of endoscopic ultrasound is the fact that US-guided tissue sampling can be performed during the examination.     

Survival and prognostic indicators for cycad intoxication in dogs

Background: Cycad palms are commonly used in landscaping and ingestion by dogs can cause disease or death. Objectives: Determine the morbidity and case fatality of cycad palm toxicosis in dogs from Louisiana, and examine putative prognostic factors. Animals: Thirty‐four client‐owned dogs with confirmed cycad palm toxicosis between 2003 and 2010. Methods: Retrospective cohort study. Search of all medical records for animals with cycad palm toxicosis. Results: Seventeen of 34 (50%) dogs died or were euthanized as a direct consequence of cycad intoxication. There were no differences in presenting signs and physical examination findings between survivors and nonsurvivors. Nonsurvivors had higher serum alanine transaminase activity (median 196 U/L; range 16–4,123 versus 113.5; 48–1,530) and total bilirubin concentration (0.5 mg/dL; 0.1–6.2 versus 0.25; 0–1.7) upon presentation, and their initial serum concentrations of albumin (2.9 g/dL; 1.4–4.1 versus 3.3; 2.2–3.9) were lower than those of survivors. Nadir serum albumin concentration was also lower in nonsurvivors (1.9; 1.4–3.7 versus 3.2; 1.8–3.5). A higher proportion of nonsurvivors had prolonged coagulation times, prothrombin time. and partial thromboplastin time. In a multivariate model, administration of charcoal at initial presentation was associated with longer survival (heart rate [HR] 0.019, 95% CI 0.001–0.644), while high serum aspartate aminotransferase activity was a negative prognostic factor (HR 118.2, 95% CI 2.89–4,826). Conclusions and Clinical Importance: Cycad intoxication is associated with a higher case fatality than previously published. Several laboratory parameters might help differentiating potential nonsurvivors from survivors. Administration of charcoal as part of the emergency treatment appears to have a protective effect.     

Computed tomography features of bronchial and non-bronchial collateral arterial circulation development in a dog diagnosed with multiple chronic pulmonary thrombi

A 5 year-old female Lhasa Apso was diagnosed with a large right pulmonary artery thrombus, multiple smaller pulmonary thrombi, and pulmonary hypertension. In addition, thoracic computed tomography angiography revealed numerous periesophageal arterial vessels, tortuous and dilated bronchial arteries, and an enlarged tortuous left phrenic artery, consistent with systemic bronchial and non-bronchial collateral arterial circulation development. These features of chronic pulmonary arterial thrombi have not been described in dogs but are recognized in people. One year after the diagnosis, the dog was still alive and there were no clinical signs reported.