Principles of transfusion medicine in small animals.

The purpose of this review was to provide the reader with an updated overview of small animal transfusion medicine, and an approach to integrating it into private practice, based on a review of the veterinary and human literature spanning the last 3 decades. Electronic, online databases that were searched included CAB International and Medline; multiple keywords or subject headings were searched that were appropriate to each of the sections reviewed: canine and feline blood groups, blood-typing and crossmatching, donors, blood collection, storage, blood components, blood transfusion, blood component therapy, blood substitutes, and adverse reactions. The safe use of blood component therapy requires knowledge of blood groups and antibody prevalence, and knowledge of the means to minimize the risk of adverse reactions by including the use of proper donors and screening assays that facilitate detection of serological incompatibility. The 2 assays available to the practitioner are crossmatching, which is readily done in-house, and blood typing. Blood typing is available in the form of a commercial testing kit, through use of purchased reagents, or via a request to an external laboratory. The risk of potentially fatal adverse reactions is higher in cats than in dogs. The decision to transfuse and the type of product to administer depend on several factors, such as the type of anemia and the size of the animal. In conclusion, transfusion medicine has become more feasible in small animal practice, with improved access to blood products through either on-site donors, the purchase of blood bank products, external donor programs, or the availability of blood component substitutes.

Synovial sarcoma in an Ayrshire heifer.

An 8-month-old Ayrshire heifer had a rapidly growing mass in the axillary region of the left thoracic limb. The mass surrounded the distal humerus and entrapped nerves of the brachial plexus, causing an abnormal gait. Histologically, the mass was composed of clusters and cords of round to polygonal cells with scattered, spindle-shaped cells. The neoplastic cells stained positively for vimentin and cytokeratin. No staining was found with S-100 protein, kappa and lambda light chains, or T-cell markers by immunohistochemistry. On electron microscopic evaluation, the cytoplasm of the neoplastic cells contained few organelles, principally rough and smooth endoplasmic reticulum and mitochondria. This synovial sarcoma has histologic and ultrastructural features characteristic of the poorly differentiated subtype of synovial sarcoma in the human classification system.

Atypical sporadic lymphosarcoma in a 7-month-old Holstein heifer.

A 7-month-old calf with a firm, diffuse infiltration of the left hind limb with sciatic nerve motor deficit was presented. The cytology indicated a malignant, round cell tumor and at necropsy, tissues were positive to a Kappa-lambda immunohistochemistry test. The final diagnosis was sporadic bovine leukosis, juvenile form.

Evaluation of chromogenic substrate assays for fibrinolytic analytes in dogs.

OBJECTIVE: To evaluate the ability of commercial, chromogenic kits designed to measure human fibrinolytic pathway components to measure the canine plasma fibrinolytic pathway enzymes, tissue plasminogen activator (tPA) and plasminogen (PLG), and their respective inhibitors, plasminogen activator inhibitor 1 (PAI) and alpha 2-antiplasmin (AP). ANIMALS: 20 healthy dogs of various ages and breeds. PROCEDURE: The commercial procedure was adapted to a microtitration plate. Standard curves were generated by use of a canine plasma pool. RESULTS: Modifications of the commercial kit consisted of change in incubation periods and the substitution of urokinase for the streptokinase. Plasminogen and AP procedures yielded intra- and interassay coefficients of variation (CV) ranging from 2 to 6.4%. The tPA activity gave an acceptable intra-assay CV of 4.2%, but an equivocal interassay CV of 18%. The PAI assay gave unacceptable intra-assay and interassay CV of 59 and 66%, respectively. CONCLUSIONS: Modifications of the commercial PLG and AP procedures were appropriate for use with fresh and frozen canine plasma. However, equivocal results were obtained for canine plasma tPA. Although the PAI assay was able to detect the inhibitor, it gave unacceptable quantifiable results. Human and canine plasma contained similar amounts of PLG and AP, but 25% more tPA was found in canine plasma than human plasma. CLINICAL RELEVANCE: With modifications, the commercial human PLG and AP chromogenic kits may serve to elucidate such canine fibrinolytic disorders as disseminated coagulopathy. The high cost of the chromogenic substrate limits its application.

Fibrinolytic activity in dogs after surgically induced trauma.

OBJECTIVE: To determine whether alterations in the fibrinolytic pathway analytes, plasminogen (PLG), tissue plasminogen activator, and alpha 2-antiplasmin are significant in dogs subjected to minor and major surgical trauma. ANIMALS: 18 dogs in 3 groups of 6 each. PROCEDURE: Plasma fibrinolytic pathway analytes were measured in dogs with trauma of ovariohysterectomy (minor trauma) or orthopedic surgery (major trauma) and halothane anesthesia (control group). A commercial procedure adapted to a microtitration plate was used to measure the analytes. Blood was obtained 24 hours before anesthesia, at extubation (0 hours), and again at 2, 24, and 48 hours after extubation. An analyte quality-control strategy was maintained. RESULTS: In the major trauma group, there was a significant, transient, postsurgical decrease in PLG activity at 0 and 24 hours and a return to presurgical values by 48 hours. The minor trauma group had a similar trend without significant changes, including an increase in PLG values at 48 hours that exceeded the reference range. Antiplasmin values changed significantly in the major trauma group only. Tissue plasminogen activator values remained within the reference range. CONCLUSIONS: Tissue plasminogen activator was not considered a clinical marker of interest for detection of alterations in fibrinolysis after trauma. In contrast, plasma PLG and alpha 2-antiplasmin values may be useful in the evaluation of hemostatic complications of surgery. CLINICAL RELEVANCE: Identification of altered fibrinolysis in dogs undergoing traumatic surgery may provide a baseline for preventive pre-and postsurgical hemostatic care.

Acute lymphoblastic leukemia, hypercalcemia, and pseudohyperkalemia in a dog.

A 5-month-old sexually intact male Chesapeake Bay Retriever was evaluated for lameness of 2 weeks' duration and lymphocytosis. Acute lymphoblastic leukemia was diagnosed on the basis of results of cytologic and cytochemical evaluation of a bone marrow aspirate. Serum biochemical abnormalities included hypercalcemia and hyperkalemia. Hypercalcemia was likely paraneoplastic; hyperkalemia was believed to be a result of release of potassium from large numbers of lymphocytes in vitro (pseudohyperkalemia). The dog was euthanatized, and necropsy revealed infiltration of the hepatic vasculature and sinusoids, renal parenchyma, mesenteric and peripheral lymph nodes, bone marrow, and iridial tissue with neoplastic cells. Unique features of this case include the young age of the dog and the hypercalcemia and hyperkalemia associated with acute lymphoblastic anemia.