John H. Lumsden

The pathogenesis of Trypanosoma congolense infection in calves. III. Neutropenia and myeloid response.

Calves infected with Trypanosoma congolense TREU 112 had, at the onset of anemia, a very low total white cell count and neutropenia but with chronicity there was lymphocytosis. Infected calves had a marked reduction in granulocyte mobilization for the first 14 weeks of infection and there was reduced ability to mount an inflammatory response during the onset of anemia. Bone marrow aspiration biopsies showed marked erythroid hyperplasia in response to the anemia with a relative and likely absolute reduction in myeloid precursors and marrow granulocyte reserves.

Histocytology of lymphoid tumors in the dog, cat and cow.

In a retrospective study of lymphomas in animals, tumors in 72 dogs, 81 cats and 90 cows were classified on the basis of cell size (small, medium and large), nuclear cleavage (follicular center cells), and histologic architecture (nodular or diffuse). Each subtype was classified by age of animal at death, number of metastases, breed, and sex. As in man, nodular cleaved tumors are rare in animals, the cow having the most varied tumor types. There was one cleaved-cell tumor in 72 lymphomas in dogs, 23 of 81 in cats, and 33 of 90 in cows. There were six nodular tumors of 72 in dogs, two of 81 in cats, and eight of 90 in cows. Fifteen of 16 nodular lymphomas had noncleaved cells and twelve had small or predominantly small cells. Cats with nodular lymphomas were older at death than cats with diffuse lymphomas. Nodularity was not associated with greater age at death in dogs and cows. Animals with cleaved-cell lymphomas were older at death than those with noncleaved tumors; this difference was highly significant in cows. The number of metastases was greater with nodular tumors in all three species, and was equal in cleaved and noncleaved tumors. The biological behaviour of lymphoid tumors in animals is similar to those in man when the same criteria of classification are used.

Clinical chemistry. In-clinic analysis, quality control, reference values, and system selection.

The clinician never has had a better selection of user friendly analytical systems for in-clinic use. Selection of a system should be made only after several questions have been answered, including: What is the technical knowledge and experience of the persons who will use the system? Who will initiate and supervise a quality assurance program? Which analysis and what volume of samples are anticipated now and in the future? The estimated cost per test should include the total cost of instrumentation and maintenance, calibrators, controls, reagents, and technical and supervisory time. Have the methods been validated for the animal species involved and are adequate reference values available? Read the package inserts completely for each analyte. Do not rely on the advice of salespeople for guidance in answering many of these questions, but do question them carefully about statements made, especially regarding warranties and technical service. For those clinicians willing to accept the responsibilities associated with in-clinic testing, an increased awareness of laboratory medicine and a resulting increased interest and ability to provide quality medical care can be expected.

Laboratory Diagnosis of Malassimilation

In many instances, the cause for malassimilation can be determined with ease, but finding the cause sometimes can be elusive and require the use of sophisticated laboratory techniques not available to the general veterinary practitioner. In either case, the clinician, whether generalist or specialist, must make an informed decision based on the results of many different testing modalities, and not only on the results of the laboratory tests described here. A flow chart is provided to assist the diagnostician in selecting and applying the more clinically oriented laboratory tests useful in dealing with a patient with chronic diarrhea and weight loss.