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  • Author or Editor: Jörg Bücheler x
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Summary

Although nearly all domestic shorthair and longhair cats have type-A blood (> 99%), the frequency of blood type B in various feline breeds ranges from 0 to 59%. All blood-type-B cats have strong natural alloantibodies, predominantly of the IgM class, whereas blood-type-A cats have low alloantibody titers of the IgG and IgM classes. We therefore studied the efficacy and safety of transfusing 20 ml of matched and mismatched 14C-potassium cyanate-labeled blood to cats. In autologous and allogeneic matched transfusions of blood-type-A and type-B cats, the half-life of labeled erythrocytes proved to be similar (29 to 39 days). In contrast, type-B erythrocytes transfused into 5 blood-type-A cats had a mean (± sd) half-life of only 2.1 ± 0.2 days and induced minor transfusion reactions. Half of the type-A blood given to 4 blood-type-B cats was destroyed within minutes to 6 hours (mean ± sd = 1.3 ± 2.3 hours), depending on the alloantibody titer. After 1 day, none of the labeled erythrocytes were detected. Mismatched transfusions in blood-type-B cats caused marked transient reactions including systemic anaphylactic signs (hypotension, bradycardia, apnea, urination, defecation, vomiting, and severe neurologic depression) and hemolytic signs (hemoglobinemia and pigmenturia) associated with severe reduction in plasma alloantibody titer and complement activity.

We conclude that the rapid destruction of type-A erythrocytes transfused into blood-type-B cats predominantly occurs intravascularly and is complement- and IgM-mediated, whereas type-B erythrocytes administered to blood-type-A cats are mostly extravascularly hemolysed by a process involving small amounts of IgG and IgM, but without marked complement activation. Thus, any first or subsequent AB-mismatched transfusions are ineffective and life threatening. We therefore recommend the practice of blood typing or cross-matching prior to transfusing blood in cats to prevent any incompatibility reactions and to assure efficacy.

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in Journal of the American Veterinary Medical Association

Summary

A method for measuring canine heart size in radiographs was developed on the basis that there is a good correlation between heart size and body length regardless of the conformation of the thorax. The lengths of the long and short axes of the heart of 100 clinically normal dogs were determined with calipers, and the dimensions were scaled against the length of vertebrae dorsal to the heart beginning with T4. The sum of the long and short axes of the heart expressed as vertebral heart size was 9.7 ± 0.5 vertebrae. The differences between dogs with a wide or deep thorax, males and females, and right or left lateral recumbency were not significant. The caudal vena cava was 0.75 vertebrae ± 0.13 in comparison to the length of the vertebra over the tracheal bifurcation.

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in Journal of the American Veterinary Medical Association

Summary

The sensitivity and specificity of 2 antibody tests for diagnosis of idiopathic thrombocytopenic purpura (itp) in dogs were investigated prospectively. An elisa to detect antibodies bound to the surface of platelets from affected dogs (direct test) was performed in 34 dogs with a clinical diagnosis of itp and in 21 dogs with thrombocytopenia attributable to other causes. An elisa to detect platelet-bindable antibodies in serum from affected dogs (indirect test) was performed in 32 dogs with itp and in 15 dogs with other causes of thrombocytopenia. The direct test was positive in 32 of 34 dogs with itp (sensitivity, 94%) and negative in 13 of 21 dogs with other causes of thrombocytopenia (specificity, 62%). Positive direct test results were obtained in 2 dogs with systemic lupus erythematosus, and in 1 dog each with concurrent Ehrlichia canis and Babesia canis infections, dirofilariasis, myelodysplasia, disseminated intravascular coagulation (of unknown cause), and thrombocytopenia subsequent to administration of trimethoprim/sulfadiazine, as well as in 1 dog with thrombocytopenia 14 days after a whole blood transfusion. The indirect test had positive results in 11 of 32 dogs with itp (sensitivity, 34%) and negative results in 12 of 15 dogs with other causes of thrombocytopenia (specificity, 80%). Positive indirect test results were obtained in 1 dog each with systemic lupus erythematosus, concurrent E canis and B canis infections, and thrombocytopenia subsequent to administration of trimethoprim/sulfadiazine. Detection of platelet-bound antibodies was more sensitive than detection of serumplatelet bindable antibodies in confirming a diagnosis of itp in dogs. Neither test was specific for itp. Therefore, a negative test result for platelet-bound antibodies in dogs with thrombocytopenia is helpful in excluding itp as a cause of thrombocytopenia; however, a positive test result is not specific for itp, and other causes of immune-mediated thrombocytopenia must be excluded to establish a diagnosis of itp.

Free access
in Journal of the American Veterinary Medical Association