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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

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.

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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

Medical records of 11 cats with lymphoma involving large granular lymphocytes were reviewed. All 9 cats tested were FeLV-negative. Ten cats had a history of anorexia, lethargy, vomiting, or diarrhea, and had lymphoma involving abdominal viscera. The most common site of tumor in these cats was the jejunum. One cat had cutaneous masses caused by dermal and epidermal infiltration with neoplastic large granular lymphocytes. The most common hematologic abnormality was leukocytosis, characterized by neutrophilia with a left shift (7 cats); 2 cats had a left shift without neutrophilia. None of the cats had lymphocytosis, but immature large granular lymphocytes were found in the blood of 4 cats. The most common serum biochemical abnormalities were hypoalbuminemia (10 cats), hypocalcemia (10 cats), hypoproteinemia (9 cats), high aspartate transaminase activity (9 cats), and hyperbilirubinemia (8 cats).

Large granular lymphocytes were characterized by abundant cytoplasm containing distinct azurophilic granules that varied in size and number. The most common cytochemical staining pattern included detection of α-naphthyl butyrate esterase, acid phosphatase, and β-glucuronidase activities. On examination of histologic sections, granules stained weakly eosinophilic with Giemsa and moderately with periodic acid-Schiff reaction. Ultrastructurally, the granules appeared membrane bound and contained an electron-dense matrix in 4 cats.

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in Journal of the American Veterinary Medical Association