REVERSIBLE MAGNETIC RESONANCE IMAGING ABNORMALITIES IN DOGS FOLLOWING SEIZURES

Reversible magnetic resonance (MR) imaging lesions have been described in humans following seizures. This condition has not yet been reported in animals. This paper describes reversible abnormalities identified in 3 dogs using MR imaging that was performed initially within 14 days of the last seizure and follow-up imaging that was performed after 10 to 16 weeks of anticonvulsant therapy. All three dogs had lesions in the piriform/temporal lobes, characterized by varying degrees of hyperintensity on T2-weighted images and hypointensity on T1-weighted images. In one dog, contrast enhancement was evident. On reevaluation, partial resolution occurred in all 3 dogs. In a fourth animal with an olfactory meningioma, similar appearing lesions in the temporal cortex and right and left piriform lobes were identified after seizure activity. A surgical biopsy of the temporal cortex and hippocampus was performed and edema, neovascularization, reactive astrocytosis, and acute neuronal necrosis were evident. These histologic findings are similar to those reported in humans with seizures. Recognizing the potential occurrence of reversible abnormalities in MR images is important in developing a diagnostic and therapeutic plan in canine patients with seizures. Repeat imaging after seizure control may help differentiate between seizure-induced changes and primary multifocal parenchymal abnormalities.     

Development of a PCR test for rapid diagnosis of contagious equine metritis

In order to establish a rapid diagnostic method for contagious equine metritis (CEM), we developed and evaluated a polymerase chain reaction (PCR) test. Species-specific PCR primer sets were derived from the DNA sequence of a cloned DNA fragment of Taylorella equigenitalis that did not hybridize with the genome of a taxomonically related species, Oligella urethralis. Single step PCR with primer set P1-N2 and two-step semi-nested PCR with primer sets P1-N2 and P2-N2 detected as low as 100 and 10 CFU of the bacteria, respectively. Single-step PCR detected T. equigenitalis from genital swabs of experimentally infected mares with sensitivity comparable to that of bacterial isolation. Furthermore, two-step PCR was more sensitive than the culture method. Upon examination of field samples, 12 out of 3,123 samples were positive by single-step PCR while only 2 were positive by bacterial culture. The 12 PCR-positive samples originated from 5 mares, of which 3 animals were considered to be carriers based on previous bacteriologic and serologic diagnoses for CEM. The PCR test described in this study would provide a specific and highly sensitive tool for the rapid diagnosis of CEM.     

Plasma myeloperoxidase level and polymorphonuclear leukocyte activation in horses suffering from large intestinal obstruction requiring surgery: preliminary results.

Myeloperoxidase (MPO) is a specific enzyme of neutrophil azurophilic granules with a strong oxidative activity. Thanks to a radioimmunoassay of equine myeloperoxidase, the authors have observed a significantly higher plasma level of MPO in horses operated for strangulation obstruction of the large intestine (n = 6) than in horses suffering from a non-strangulating displacement of the large intestine (n = 9). For the 2 groups, 3 phases were distinguished: reception (P1), intensive care (P2) and terminal phase (P3). The mean peak values of MPO for these phases were 121.6 ng/mL (P1), 168.6 ng/mL (P2), and 107.0 ng/mL (P3) for the non-strangulating group, and 242.6 ng/mL (P1); 426.0 ng/mL (P2), and 379.5 ng/mL (P3) for the strangulation group. The variations of the mean peak values of plasma MPO were significantly different between the 2 groups and between the different phases. A significant increase of the least square means of MPO was observed between P1 and P2. A significant decrease of the least square means of the number of circulating leukocytes was observed between P1 and P3. Polymorphonuclear neutrophil activation could play a major role in the pathogenesis of acute abdominal disease and endotoxic shock.     

Development of PCR-based tests for the identification of North American isolates of epizootic haemorrhagic disease virus.

A serogroup-specific polymerase chain reaction (PCR) assay and isolate identification strategies (restriction endonuclease analysis (REA) and nucleotide sequencing) were developed for the detection of North American isolates of epizootic haemorrhagic disease virus (EHDV). PCR primers (EHDV-pr4, EHDV-pr5) were designed to hybridize to the L3 gene of a North American isolate of EHDV serotype 1. Total nucleic acid was extracted from preparations of infected tissue culture and PCR was performed using a cDNA-PCR kit, according to the manufacturer's specifications. The PCR assay generated a 459 base pair product from North American isolates of EHDV serotypes 1 and 2, while bluetongue virus (BTV) serotypes 10, 11, 13, and 17, and cell controls, failed to demonstrate PCR products. Slight modifications allowed for the PCR detection of EHDV-1 and -2 in white-tailed deer blood (Odocoileus virginiatus); PCR fragments were not amplified from uninfected deer blood. A number of restriction endonucleases and sequencing primers were evaluated for their utility in isolate identification experiments. Specifically, REA employing HincII and cycle sequencing with an internal primer (EHDV-1-pr3) proved most successful for identifying isolate-specific genome markers. The techniques presented are expected to prove valuable for rapid and specific detection of possible future EHDV incursions in wild and domestic animal species.     

Comparative Evaluation of Two Surgical Scrub Preparations in Cattle

One hundred seventeen cattle that had undergone surgery were assigned randomly to two preoperative skin preparation protocols. Group 1 (60 animals) skin preparation was with povidone-iodine soap and isopropyl alcohol, whereas group 2 (57 animals) had skin preparation with chlorhexidine gluconate and isopropyl alcohol. Quantitative microbial culture plates were used to estimate the number of colony forming units (CFUs) before skin preparation (prescrub), after skin preparation (postscrub), after surgery (postoperative), and in room air (environment). A significant decrease in CFU occurred postscrub for both skin preparations ( P <.05). Chlorhexidine and alcohol preparation resulted in significantly fewer CFUs (LSMean ± SE = 2.79 CFU ± 1.74) and a greater percentage reduction in CFUs (98.64%± 2.01) postscrub than povidone and alcohol (LSMean ± SE = 10.27 CFUs ± 1.51, 93.29%± 1.85); ( P <.005). Group 2 had a significantly higher frequency of negative cultures postscrub (49.1%) compared with group 1 (18.3%) ( P <.001). The number of postoperative CFUs were not significantly different between the two treatment groups. Wound infection frequency for clean surgical procedures was not significantly different between the two skin preparation protocols (group 1 = 9.8%, group 2 = 10.7%), however, infection frequency was significantly higher for surgical procedures with a ventral abdominal approach (5 of 14, 35.7%), compared with a flank approach (1 of 41, 2.4%) or other approaches (orthopedic procedures) (1 of 16, 6.3%) ( P <.05). Both skin preparation protocols were effective and safe in decreasing the skin microflora population of cattle before surgery and although preparation with chlorhexidine gluconate and alcohol resulted in less CFUs immediafly postscrub, the frequency of surgical wound infection was similar for both protocols.     

Idiopathic, aseptic, effusive, fibrinous, nonconstrictive pericarditis with tamponade in a standardbred filly.

A Standardbred filly was admitted for evaluation of pleuritis and pneumonia. Heart rate was 80 to 120 beats/min, and the pulse was barely palpable. Thoracic and abdominal ultrasonography and echocardiography revealed substantial pericardial effusion with cardiac tamponade, fibrinous pericarditis, pleural effusion, and ascites. Initial electrocardiography revealed normal sinus rhythm with decreased amplitude of the QRS complexes consistent with pericardial effusion. Following thoracentesis, echocardiogram-guided pericardiocentesis was performed. Bacterial culture yielded no growth from any of the fluids, and bacteria were not seen on cytologic examination. Initial treatment included broad-spectrum antibiotic treatments, IV fluid therapy, and anti-inflammatory agent administration. On the basis of negative culture results, an immune-mediated cause was considered, and dexamethasone was instituted in a decreasing dosage regimen. Pericardial effusion, ventral edema, and ascites began to resolve within 3 days after beginning dexamethasone treatment. Thirty days following discharge, the filly was reexamined, and at that time, the prognosis for athletic performance was considered good so the horse was returned to race training. The final diagnosis in this case was idiopathic, effusive, nonconstrictive pericarditis with tamponade. Early identification, clinical understanding, and application of knowledge of the pathophysiologic mechanisms of pericarditis in horses, combined with use of diagnostic aids such as ultrasonography and aggressive therapy consisting of effusion drainage, pericardial lavage, antibiotics that penetrate the pericardium, and corticosteroids when indicated are critical for a successful outcome in horses with pericarditis.     

Efficacy of a drug combination of praziquantel, pyrantel embonate, and febantel against helminth infections in dogs.

Tablets containing praziquantel, pyrantel embonate, and febantel were tested for efficacy against helminths in dogs. A single treatment with this drug combination gave 100% reductions in Toxocara canis and Taenia hydatigena in experimentally induced infections in dogs. In dogs with naturally acquired infections, treatment gave > 97 to 98% reductions in fecal egg counts attributable to Toxascaris leonina, T canis, and Uncinaria stenocephala. Efficacy against Trichuris vulpis was > 92%.