V. E. O. Valli

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.

The Pathogenesis of Trypanosoma congolense Infection in Calves. II. Anemia and Erythroid Response

The anemia caused by Trypanosoma conogolense TREU 112 in Holstein calves was of moderate severity and normochromic, macrocytic in the acute phase changing to normochromic, normocytic with chronicity. The anemia was hemolytic and responsive as shown by sharply decreased myeloid:erythroid ratio and increased mean corpuscular volume. 51Cr red cell labelling studies showed that red cell lifespan was halved in the acute phase and there was an increase in plasma volume. Surface organ counting of liver showed it to be the major site of red cell destruction. The anemia was partly dilutional as a result of the increased plasma volume and primarily hemolytic likely of a non-specific immune (innocent bystander) pathogenesis.

The Pathogenesis of Trypanosoma congolense Infection in Calves V. Quantitative Histological Changes

Calves infected with Trypanosoma congolense TREU 112 had generalized microvascular dilation which was most prominent in the liver and the mesentery; there also was increase in cellularity in the lung with significant alveolar thickening and accumulation of hemosiderin-bearing cells in the alveolar septa, focal accumulations of lymphocytes primarily at the corticomedullary junction of the kidneys and a well developed glomerulonephritis, likely membranoproliferative. Reticuloendothelial changes were marrow hyperplasia with an erythroid shift, moderate hemosiderosis and moderate dysthrombopoiesis, marked thymic cortical atrophy, hypersplenism and enlarged nodes with reduced cellular density, paracortical atrophy and medullary sclerosis.

The pathogenesis of Trypanosoma congolense infection in calves. IV. The kinetics of blood coagulation.

Blood coagulation studies showed there was a pronounced thrombocytopenia and hypofibrinogenemia in Holstein calves infected with Trypanosoma congolense TREU 112. There was also ineffective thrombopoiesis characterized by an increased megakaryocytic mass, reduced uptake of 35S-methionine into peripheral blood platelets and a normal platelet lifespan. There was an increased uptake of isotopic label into fibrinogen and a shortened half life indicating a consumptive error with increased peripheral use of fibrinogen. No consistent abnormalities were found in ethanol gelation, partial thromboplastin time, clot retraction and lysis or plasminogen assay. Fibrin split products were rarely detected. These findings suggest that in the chronic form of bovine trypanosomiasis there is a partially compensated consumption coagulopathy.

The Pathogenesis of Trypanosoma congolense Infection in Calves. I. Clinical Observations and Gross Pathological Changes

Holstein calves infected with Trypanosoma congolense TREU 112 had intermittent fever, debility and a poor hair coat. At postmortem examination the most significant findings were enlargement of the liver, kidneys and spleen and increased volume of hematopoietic marrow. A group of 13 calves infected for 18 weeks had marked enlargement of lymph nodes throughout the body and hemal nodes were prominent in the sublumbar area caudal to the kidneys. Another group infected for 7 weeks had no increase in the weight of lymph nodes. Studies with 51Cr labelled autologous red cells given shortly before postmortem examination showed that the liver was the most active organ with respect to sequestration of labelled red cells.

Production of anti-NC1 antibody by affected male dogs with X-linked hereditary nephritis: a probe for assessing the NC1 domain of collagen type IV in dogs and humans with hereditary nephritis.

Some patients with hereditary nephritis (HN) who have received a renal transplant have been shown to form antibody with specificity for the NC1 domain of collagen type IV, a major constituent of glomerular basement membranes (GBM). We attempted to duplicate this phenomenon in a family of dogs with X-linked HN, a model for human X-linked HN, by immunizing affected male dogs with normal dog NC1 domain. A collagenase digest was prepared from normal dog GBM, the NC1 domain was separated into dimer (∼50 kDa) and monomer (24 kDa and 26 kDa) components by SDS-PAGE, and injected into two affected male dogs. Antisera obtained from both dogs contained antibody which reacted with the NC1 domain of dog and human GBM by a plate-binding radioimmunoassay, bound to the dimer and 26 kDa monomer bands by Western blotting, and staining dog and human GBM by immunofluorescence (IF). The affected male dog antiserum reacted equally by radioimmunoassay with the NC1 domain isolated from GBM of unaffected, affected male, and carrier female dogs in the family with X-linked HN, and bound by Western blotting to dimers and the 26 kDa monomer band of the NC1 domain of GBM in each group of dogs. However, the affected male dog antiserum differentiated these dogs by IF; it produced global staining of GBM of unaffected dogs, failed to stain GBM of affected male dogs, and produced segmental staining of GBM of carrier female dogs. Absorption of the affected male dog antiserum with normal dog NC1 domain eliminated the staining of dog GBM by IF, whereas staining persisted after absorption with affected male dog NC1 domain. The abnormal staining patterns of GBM seen by IF in the affected male and carrier female dogs and the results of the absorption studies imply an abnormality of one or more determinants in the 26 kDa monomer band of the NC1 domain of their GBM. Amino acid sequencing of this band identified the α1(IV) chain of collagen type IV, a finding that has implications for the pathogenesis of canine X-linked HN. Absent and segmental staining respectively were also seen by IF in GBM of a male and female patient with HN, using the affected male dog antiserum. Thus, the results obtained in affected male and carrier female dogs with X-linked HN may also be relevant to patients with this disease.

Quantitation of anionic sites in glomerular capillar basement membranes of Samoyed dogs with hereditary glomerulopathy

Samoyed hereditary glomerulopathy (SHG) is an X-linked dominant disease characterized by proteinuria and renal failure in affected male dogs. Electron microscopic examination of glomerular capillary basement membranes (GCBM) shows widespread multilaminar splitting of the lamina densa, identical to that in Alports syndrome. Anionic sites in GCBM of three affected males and five unaffected dogs were labeled using polyethyleneimine to determine whether proteinuria was associated with an alteration in their number. No significant differences were noted in the number of anionic sites in the lamina rara externa, whereas small but statistically significant increases were seen in the number of sites in the lamina rara interna of affected males. In the lamina densa, affected males showed a striking increase in anionic sites, particularly in regions of GCBM which were split. Thus, although proteinuria in some glomerular diseases has been attributed to a reduction in anionic sites in GCBM, this was not so in SHG.

An immunohistochemical and electron microscopic study of extra-renal basement membranes in dogs with Samoyed hereditary glomerulopathy.

Samoyed hereditary glomerulopathy (SHG) in dogs has been employed as a model for human hereditary nephritis (HN), since affected dogs and patients show splitting of glomerular capillary basement membranes by electron microscopy (EM) and absent staining of glomerular capillaries for Goodpasture antigen (GPA) by immunofluorescence (IF). EM and IF were used to examine basement membranes (BM) in skin, lung, choroid plexus, lens, retina, and inner ear in SHG. By EM, BM in these tissues appeared similar in affected male, carrier female, and unaffected dogs. By IF, GPA could be detected only in lens capsule, internal limiting membrane of retina and basilar membrane of inner ear of unaffected and carrier female dogs, but not in affected male dogs. However, eye abnormalities and hearing loss were not present in any dogs, in contrast to their frequent occurrence in human HN. Our findings on extra-renal BM in SHG suggest that GPA is not required to maintain normal vision or hearing in affected male dogs and permit a greater understanding of the pathogenesis of human HN.

Morphometric Evaluation of Hepatocellular Proliferative Lesions in the Rat Liver

Classification of rat hepatocellular proliferative lesions can vary between pathologists as the many qualitative histologic criteria have not been satisfactorily evaluated and ranked for prognostic value. Computer-assisted morphometry offers an objective method to evaluate certain cellular features. The Solt-Farber resistant hepatocyte model was used in this study to produce populations of rats with a full range of hepatocellular proliferative lesions. Cellular features within the lesions were then measured morphometrically and the data were analyzed by animal age and by subjective lesion diagnosis. The nuclear/cytoplasmic ratio followed by the cell area and nuclear area were found to be the most important parameters for separating microscopic foci and islands of cellular alteration, an early hyperplastic lesion, from other hepatocellular proliferative lesions. The coefficient of variation, as a relative measure of heterogeneity, increased in a linear manner for cell, nuclear and nucleolar areas as the animals aged and was significantly higher for cell and nuclear area in hepatocellular carcinoma compared to other hepatocellular proliferative lesions. Hepatocyte nodules (representing primarily late hyperplastic lesions) and persistent hepatocyte nodules (lesions with similarities to hepatocellular adenoma) could not be satisfactorily seaprated within the limits of this study. As these borderline lesions show a continuum of cytologic change, other features, such as architectural change, are necessary to satisfactorily classify them on a subjective basis. An alternative approach is to use discriminant functions derived from morphometric studies.