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in Journal of the American Veterinary Medical Association

Summary

Coombs-positive anemia developed in cats inoculated with Haemobartonella felis. Cold agglutinins were detected in serum during the acute stage of the disease when anemia was present. The cold agglutinating activity was associated with IgM, was demonstrated at 4 C, and was abolished by treatment of sera with 2-mercaptoethanol. At 4 C, the sera from infected cats agglutinated or lysed parasitized autologous erythrocytes or normal erythrocytes pretreated with neuraminidase. These data indicate that cold agglutinins are associated with haemobartonellosis and suggest that immunologic responses to erythrocytic antigens have a role in the anemia.

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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Summary

Direct effects of equine infectious anemia virus (eiav) on hematopoiesis in vitro were studied. Bone marrow mononuclear cells from clinically normal horses were incubated with 100 TCID50 of ELAV/107 cells. These cells were cultured to assay for colonies derived from erythroid pro-genitors, granulocyte/monocyte progenitors, and fibroblastic progenitors. The eiav had a selective suppressive effect on the erythroid progenitors. Colony-forming units-erythroid were suppressed to 80% of that for medium controls (P = 0.011). Burst-forming units-erythroid were suppressed to 70% of that for medium controls (P = 0.003). Significant effect was not apparent on colony-forming units-granulocyte/macrophage or on colony-forming units-fibroblastic.

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in American Journal of Veterinary Research

SUMMARY

Bone marrow fibroblast colony-forming units (cfu-f) were evaluated in cats experimentally infected with different isolates of FeLV. Cats infected with the Kawa-kami-Theilen isolate of FeLV (FeLV-KT) had progressive decrease in the number of cfu-f at 2, 4, and 6 weeks after infection. The number of cfu-f in FeLV-KT-infected cats ranged from 38 to 70% of the preinoculation cfu-f value. Of 3 cats with FeLV-KT-induced suppression of cfu-f, 2 developed fatal nonregenerative anemia. Cats infected with the Rickard isolate of FeLV (FeLV-R) had more moderate decrease in the number of cfu-f at 2, 4, and 6 weeks after infection. The number of cfu-f in FeLV-R-infected cats ranged from 62 to 82% of the preinoculation cfu-f value. The FeLV-R-infected cats did not become anemic.

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in American Journal of Veterinary Research

SUMMARY

Chemotaxis under agarose was evaluated to establish an assay system and to characterize chemotactic responses of canine neutrophils. A method for the measurement of canine neutrophil chemotaxis was established, with optimal responses obtained with agarose containing 10% pooled canine serum, a concentration of 5 × 105 cells/well, zymosan-activated serum (zas), or autologous serum or plasma as the chemoattractants, and a 120-minute incubation period. Canine neutrophils responded well to zas, heat-inactivated zas, autologous serum and plasma, and heat-inactivated pooled serum. Chemotactic activity was proportional to the concentration of serum used as the chemoattractant. Mean (± sd) random migration, chemotaxis, chemotactic index, and chemotactic differential of neutrophils from 9 healthy Greyhounds were 1.09 (± 0.23), 1.95 (± 0.38), 1.82 (± 0.31), and 0.86 (± 0.32) mm, respectively.

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in American Journal of Veterinary Research

SUMMARY

Phosphonoformate (pfa), a noncompetitive inhibitor of reverse transcriptase (rt), inhibited feline leukemia virus (FeLV) infection of 2 feline cell lines and inhibited progeny virus rt activity in a chronically FeLV-infected cell line. Feline leukemia virus infection of 3201 cells, an FeLV-negative lymphoma cell line, was inhibited by > 70% at a concentration of only 1 μM pfa and by > 90% at concentrations of 64 to 256 μM pfa, as evidenced by rt activity. However, FeLV antigen expression by 3201 cells remained relatively constant over noncytotoxic concentrations of pfa. Because the persistence of viral antigen expression with concomitant suppression of rt activity appears to be unique and because 3201 cells express small amounts of an endogenous retrovirus (RD-114) and contain endogenous FeLV proviral sequences, a possible role of endogenous retroviruses acting as helper viruses was suggested. Feline leukemia virus infection of 81C cells, a sarcoma-positive, leukemia-negative fibroblast cell line, was inhibited by > 50% at a concentration of 64 μM pfa and by > 98% at concentrations of 256 to 512 μM pfa, as indicated by suppression of focus formation. The feline lymphoid cell line FL-74 is a large producer of FeLV. When FL-74 cells were cultured in the presence of 256 μM pfa, virus production (virus budding and viral antigen) was not affected, but progeny virus lost rt activity and infectivity. Direct addition of pfa (256 μM) to FeLV also reduced rt activity and infectivity. These data indicate that pfa can directly and rapidly inactivate retrovirus independent of cellular processing, presumably by inhibiting rt. Long-term pfa administration may curtail spread of retroviral infections within and between hosts via extracellular inactivation of newly produced virus particles. Results of this study also suggest that pfa might be used prophylactically to treat materials potentially contaminated with retroviruses.

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in American Journal of Veterinary Research

Abstract

Objective

To determine reference ranges for hematologic and serum biochemical variables of bulls residing at an artificial insemination center.

Animals

225 healthy Holstein bulls categorized by age into yearling, intermediate age, and adult groups.

Procedure

Hematologic and serum biochemical analyses were performed on 1 blood and 1 serum sample from each bull.

Results

Significant differences associated with age were identified for 25 of 33 variables. Serum creatinine concentration for clinically normal adult bulls (2.44 ± 0.33 mg/dl) was higher than previously reported reference values for adult cattle. There was a reversal of the segmented neutrophil-to-lymphocyte ratio between yearling (0.85:1) and adult (2.6:1) bulls. This was associated with a significant and marked decrease in absolute numbers of lymphocytes per microliter between yearling (5,801 ± 1,683) and adult (1,307 ± 509) bulls.

Clinical Relevance

Reference values for selected clinicopathologic variables were generated from the data. (Am J Vet Res 1998;59:1386–1391)

Free access
in American Journal of Veterinary Research

SUMMARY

Marked differences in bone marrow cellularity were observed between cattle affected with leukocyte adhesion deficiency (lad) and control cattle. The number of nucleated cells in bone marrow was 2.9 to 8.8 times higher in cattle affected with lad, compared with controls. The myeloid-to-erythroid ratio of bone marrow from 3 cattle affected with lad ranged from 2.4 to 12. Deficient CD18 expression on neutrophils isolated from bone marrow of cattle with lad was clearly detected by flow cytometric analysis. Neutrophils from bone marrow of cattle affected with lad appeared round and not flat, after adherence to plastic wells under agarose, whereas neutrophils from bone marrow of clinically normal cattle were firmly spread on the surface of plastic wells. In the chemotaxis under-agarose assay, many pseudopodia were detected on bone marrow neutrophils from clinically normal cattle, but were not detected on bone marrow neutrophils from cattle with lad. Activities of chemotactic movements and phagocytosis of neutrophils isolated from bone marrow of cattle affected with lad were documented to be severely impaired.

Free access
in American Journal of Veterinary Research

SUMMARY

Twenty-four horses were randomly allocated to 3 groups. All horses underwent a ventral midline celiotomy, and the large colon was exteriorized and instrumented. Group-1 horses served as sham-operated controls, group-2 horses underwent 6 hours of colonic ischemia, and group-3 horses were subjected to 3 hours of ischemia and 3 hours of reperfusion. Baseline blood samples were collected, then low-flow colonic ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline. All horses were monitored for 6 hours. Citrated systemic venous ( sv ) blood samples were collected from the main pulmonary artery, and colonic venous (cv) samples were collected from the colonic vein draining the ventral colon. Samples were collected at 0, and 2, 3, 3.25, 4, and 6 hours for determination of one-stage prothrombin time, activated partial thromboplastin time, antithrombin III activity, and fibrinogen concentration. Data were analyzed statistically, using two-way anova for repeated measures, and post-hoc comparisons were made by use of Student Newman Keul's test. Statistical significance was set at P < 0.05. There were significant decreases in all hemostatic variables by 2 hours in sv and cv samples from horses of all 3 groups, but there were no differences among the 3 groups for any of these variables. These hemostatic alterations could have been secondary to a hypercoagulable state or to fluid therapy-induced hemodilution. Colonic ischemia-reperfusion was not the cause of these alterations because these alterations also were observed in the sham-operated control horses. Significant temporal alterations existed even after accounting for the hemodilution. The most plausible explanation for these alterations is that hemostatic activation was incited by the celiotomy and manipulation of the colon during exteriorization and instrumentation. Comparison of paired sv and cv samples for each hemostatic variable revealed significant differences for the absolute values of one-stage prothrombin time and fibrinogen concentration, but not for activated partial thromboplastin time or antithrombin III activity. This indicates that monitoring sv hemostatic variables does not necessarily provide an accurate assessment of hemostatic function in regional vascular beds. Largecolon ischemia with or without reperfusion did not alter hemostatic function.

Free access
in American Journal of Veterinary Research