Cranial vena caval syndrome secondary to transvenous pacemaker implantation in two dogs

Superior vena caval syndrome is a rare, but reported complication of transvenous pacemaker implantation in humans. This syndrome can occur secondary to fibrotic and/or thrombotic obstruction of venous blood flow into the right atrium. The therapeutic approach depends on the suspicion of the presence of an active thrombus and may include antithrombotics, angioplasty and/or surgical venoplasty. We describe two dogs that developed severe pleural effusion secondary to stricture formation in the cranial vena cava 4 years after dual chamber transvenous pacemaker implantation. The stenosis was most likely due to fibrosis secondary to the transvenous pacemaker leads. Balloon angioplasty of the lesion resulted in resolution of the pleural effusion in both patients. Balloon angioplasty appears to be a viable therapeutic approach in dogs with cranial vena caval syndrome caused by focal stenotic lesions.     

Effect of Sperm Cryopreservation on the European Eel Sperm Viability and Spermatozoa Morphology

The main objective of the present work was to study the effect of cryopreservation of European eel sperm both on the sperm viability and the spermatozoa head morphology. Spermatozoa morphology was evaluated with computer-assisted morphology analysis after collection in fresh samples, after adding the freezing medium containing dimethyl sulfoxide as cryoprotectant and, finally, after the cryopreservation process and thawing. Cell viability was assessed, in both fresh and thawed samples, by Hoechst 33258 staining. Computer-assisted sperm analysis (CASA) was used to determine the percentage of motile cells and to measure motility parameters in sperm samples. A significant decrease of head perimeter (12.56%) and area (17.90%) was detected from spermatozoa in fresh to thawed samples, indicating that cells do not recover the original size after the cryopreservation process. CASA was used to measure the percentage of motile cells (51.9%) and spermatozoa motility parameters such as curvilinear, straight line and angular path velocities, as well as beating cross frequency. This technique was employed in the fresh sperm samples but proteins present at the freezing medium (L-alpha-phosphatidylcholine) made impossible to use this last technique in thawed samples. When sperm viability was assessed by Hoechst staining, a significant decrease of approximately 15% (73.10 vs 58.26%) of alive spermatozoa was registered from fresh to thawed samples. The percentage of motile cells measured by CASA in fresh samples (51.9%) was lower than the percentage of alive cells determined by Hoechst stainning, suggesting the existence of different batches of spermatozoa in different stages of development, even during the eight to tenth weeks of treatment, when the highest sperm quality was found.     

Effect of clopidogrel on tissue-plasminogen activator-induced in vitro thrombolysis of feline whole blood thrombi

OBJECTIVE: To determine if clopidogrel enhanced the thrombolytic rate of tissue-plasminogen activator (t-PA) on an in vitro feline whole blood thrombosis model. ANIMALS: 9 purpose-bred cats. PROCEDURE: Blood obtained from cats before (baseline) and after treatment with clopidogrel (75 mg, p.o., q 24 h for 3 days) was anticoagulated with sodium citrate (9:1 volume-to-volume ratio) to which 1 microCi of I125-fibrinogen was added. Thrombi were formed by the addition of calcium chloride and bovine thrombin. Thrombi were placed into autologous plasma to which 0.1 mg of t-PA was added. Plasma samples were collected at different time points to determine the amount of released I125-fibrin split products. Thrombolytic rates were calculated by determining the time to 25%, 50%, and 75% thrombolysis (t25, t50, and t75, respectively). Confidence intervals for t25, t50, and t75 at baseline were compared with those after treatment. RESULTS: There were no significant differences in thrombolytic rates between values obtained at baseline and after clopidogrel treatment (t25, 18.0 vs 18.5 minutes; t50, 63.3 vs 65.6 minutes; and t75, 163.0 vs 170.1 minutes, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Clopidogrel did not have an effect on the rate of thrombolysis of feline whole blood thrombi induced by t-PA in this in vitro model.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.     

Trends in hip dysplasia control: analysis of radiographs submitted to the Orthopedic Foundation for Animals, 1974 to 1984

From 1974 through 1984, the Orthopedic Foundation for Animals evaluated 143,218 radiographic submissions representing 151 breeds of dogs. All breeds from which there were 35 or more evaluations had some frequency of dysplasia. Seventy breeds, each with over 100 submissions, were tabulated and ranked according to frequency of hip dysplasia. Frequency of dysplasia varied from 0.6% in the Borzoi to 46.9% in the Saint Bernard. These data were compared with data obtained earlier (1966 to 1973) on evaluations in 38 breeds for changes in frequency. There was significant (P less than 0.05) reduction in frequency of dysplasia in 27 breeds, a significant (P less than 0.05) increase in frequency in only 1 breed (German Shorthaired Pointer), and no significant change in frequency in 10 breeds. The median significant decrease was 22.4%, and the range was from 3.1% in the Chesapeake Bay Retriever to 48.7% in the Keeshond. The reduction in frequency of hip dysplasia demonstrated the value of a control program. There were 5 breeds with a significant (P less than 0.05) decrease in frequency of dysplasia that had over 5,000 evaluations from 1974 to 1984. The decreases in frequency were independent of changes in American Kennel Club registrations for these breeds (a dramatic decline in registrations for the German Shepherd Dog and Old English Sheepdog, and a dramatic increase for the Rottweiler, Golden Retriever, and Labrador Retriever). Frequency regressed linearly in the German Shepherd Dog and Old English Sheepdog, but regressed nonlinearly in the other 3 breeds. The percentage reduction in frequency from the base frequency (1966 to 1973) for these breeds was 17.5% for the German Shepherd Dog, 23.1% for the Old English Sheepdog, 9.1% for the Rottweiler, 10.1% for the Golden Retriever, and 6.8% for the Labrador Retriever.     

Echocardiographic evaluation of the effects of medetomidine and xylazine in dogs

The echocardiographic effects of medetomidine and xylazine were evaluated in 6 healthy dogs. Values for echocardiographic variables were significantly different from pre-treatment values after administration of both drugs. The effects of medetomidine were similar to that of xylazine. Because of their cardiac depressant effects, both drugs should be used with care in sick dogs.