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Summary

Anecdotal descriptions of atypical FeLV infections, wherein standard clinical elisa or immunofluorescence testing fails to detect active infections, suggest that an unknown proportion of FeLV-infected cats may go undetected. In this study, 127 viremic and nonviremic cats experimentally inoculated with FeLV were evaluated at necropsy for atypical expression of FeLV antigen. Results from viremic cats were in accordance with results of earlier studies on the pathogenesis of FeLV infection in cats, wherein antigen was found in lymphoid and epithelial tissues. Differences in time course or tissue distribution of viral antigen in some cats appeared to be attributable to the challenge virus preparations, consisting of cell-free tumor homogenate or infectious plasma. It was discovered that 5 of 19 of the FeLV challenge-exposed cats that were nonviremic had FeLV-specific antigens in select tissues (bone marrow, spleen, lymph node, and small intestine) 6 to 75 weeks after inoculation. These results indicated an additional category of possible outcomes for cats exposed to FeLV. Localized FeLV infection, as described here, may explain the discordance between clinical disease and laboratory testing for FeLV.

Free access
in American Journal of Veterinary Research

SUMMARY

Effects of immunosuppression were compared in newly hatched chickens given cyclophosphamide (cy) after inoculation with avian nephritis virus (anv). All cy-treated infected chickens died within 13 days after inoculation of the virus and had heavy urate deposits throughout the body. However, non-cy-treated infected, cy-treated noninfected, and non-cy-treated noninfected control chickens survived through the observation period. In a chronologic study, the value of serum uric acid in cy-treated infected chickens was more than 3 times higher than that in non-cy-treated infected chickens, and more than 9 times higher than in noninfected chickens. Serum uric acid values were coincident with the positive degree of anv antigen in the tubular epithelial cells in the kidneys and with the severity of renal degeneration. Serologic and immunohistologic examinations did not reveal detectable antibody and IgG- and IgM-containing cells in the spleen and kidneys of cy-treated infected chickens. However, non-cy-treated infected chickens had an increased number of IgM- and IgG-containing cells and antibody against anv on postinoculation day 6. These findings demonstrated that cy treatment enhanced the susceptibility of chickens to anv infection.

Free access
in American Journal of Veterinary Research

SUMMARY

Laboratory raised white-footed mice (Peromyscus leucopus) were inoculated experimentally with live spirochetes (Borrelia burgdorferi), the etiologic agent of Lyme disease (borreliosis). Prior to inoculation, mouse sera were tested with an indirect fluorescent antibody test, and all mice were seronegative. All inoculated mice seroconverted. In tick transmission studies, immature stages of Ixodes dammini and Dermacentor variabilis attached and fed to repletion on mice, but only I dammini transferred spirochetes to uninfected mice. Mice were susceptible to oral infection and transmitted infection to each other through direct contact. Infection did not affect reproduction or development of young born from infected dams, nor did spirochetes appear in the tissues of neonates. Borrelia burgdorferi spirochetes were identified in the kidneys, liver, and spleen of infected mice by the use of the modified Steiner silver stain and a tissue indirect fluorescent antibody test. Spirochetes also were isolated in culture of the heart blood of 1 mouse. Regardless of the source of infection, no mice developed clinical signs or had any pathologic change resulting from infection. Spirochetes were always observed extracellularly within interstitial spaces. Antibody titers persisted for over 4 months in some mice and spirochetes were found in the tissues of 1 mouse that had been infected 1 year earlier.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To elucidate the spatial and temporal expression of a porcine lactoferrin (LTF) gene.

Animals

4 female and 4 male Large White pigs.

Procedures

We examined LTF expression in various organs excised from the pigs, using northern blot hybridization with a porcine LTF cDNA probe. Antibodies against porcine LTF were raised in rabbits and were used along with immunohistochemical staining to localize the LTF protein.

Results

High amounts of porcine LTF mRNA were detected in the secreting mammary gland and epididymis. This distribution is consistent with that of porcine LTF examined by immunohistochemistry. In female pigs, porcine LTF mRNA concentration increased remarkably in the ductal cells of the lactating mammary gland then significantly decreased at day 21 after parturition. Furthermore, specific staining for LTF was observed in the epithelial cells of the gastrointestinal tract of female pigs, but not in the uterus, ovaries, spleen, kidneys, pancreas, muscles, heart, brain, lungs, or liver of postpartum female pigs, or in the testes of male pigs.

Conclusions

Gene expression of porcine LTF is closely related to lactation in the mammary gland. Distribution of LTF in the epididymis suggests that LTF may have a regulatory role in development of the reproductive tract of male pigs. (Am J Vet Res 1997;58:1152–1158)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To identify eosinophil progenitor cells in feline bone marrow, establishing an assay method to use in studies of eosinophilopoiesis and eosinophilopoietic factors in cats.

Animals

Healthy, laboratory animal source cats.

Procedure

Sources of colony-stimulating activity were prepared by conditioning media with bone marrow, spleen, and blood mononuclear cells from cats infected with Toxocara canis. Bone marrow cells were aspirated and cultured to develop the eosinophil progenitor cell assay and to test cells from 9 healthy cats in the assay.

Results

Optimal conditions for identifying colonyforming units-eosinophil and cluster-forming units-eosinophil were as follows. Bone marrow mononuclear cells (105) were plated in 1 ml of supplemented medium, fetal bovine serum, and agar. The source of eosinophil growth factor(s) was bone marrow-conditioned medium made in the presence of 2.5 µg of concanavalin A/ml; other conditioned media also supported eosinophil colony growth. Dishes were incubated for 7 days at 37 C and 7% CO2. The colonyforming units-eosinophil formed aggregates of > 50 Luxol fast blue-positive cells and had dispersed morphology; the cluster-forming units-eosinophil formed aggregates of < 50 cells.

Conclusion and Clinical Relevance

Similar to other species, cats have separate and distinct eosinophil progenitor cells. The eosinophil progenitor assay may be used to characterize altered kinetics of eosinophilopoiesis, to assess eosinophil growth factors, and to evaluate therapeutic regimens that might be useful in the management of excess eosinophil production. (Am J Vet Res 1997; 58:348-353)

Free access
in American Journal of Veterinary Research

-needle aspirates of the spleen by comparing those results with histologic diagnoses. Additional information about underlying disease and ultrasonographic appearance was also obtained. Criteria for Selection of Cases Medical records from 247 dogs and cats in

Full access
in Journal of the American Veterinary Medical Association

the esophageal wall was thickened ( Figure 1 ). The spleen was markedly enlarged (weight, 20 g [approx 3% of the ferret's body weight; normal spleen weight is 0.5% to 1.3% of a ferret's body weight]), had rounded edges, and was soft, pale, and mottled

Full access
in Journal of the American Veterinary Medical Association

abnormalities except mild enlargement of the spleen. A nasogastric tube was passed and no net reflux was obtained, but the gastric contents were mixed with a small amount of blood. No current signs of colic were observed. Initial bloodwork revealed a PCV of 32

Free access
in Journal of the American Veterinary Medical Association

, and others are displaced caudally. On the ventrodorsal view, the mass is on the left side of the abdomen, partially overlying the left kidney. According to the location of the mass within the abdomen, the organs potentially involved may be the spleen

Full access
in Journal of the American Veterinary Medical Association

, and hypersplenism. 1,2 The effects of drugs on splenic size have long been recognized. The effects of barbiturates on the spleen were first reported in dogs. 3 In that study, splenic size was subjectively evaluated on abdominal radiographs, which

Full access
in American Journal of Veterinary Research