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retract the spleen to expose its hilus. Beginning at the splenic tail, the vessel-sealing device was used to seal and divide the splenic hilar vasculature immediately adjacent to the splenic parenchyma. Following completion of the splenectomy, the single

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in Journal of the American Veterinary Medical Association

immediately submitted for necropsy. The body of the spleen contained a 6.5 × 7 × 4-cm, multilobulated, mottled yellow-tan to dark red mass ( Figure 1 ). On the capsular surface of all hepatic lobes, there were numerous, clearly delineated, slightly raised

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in Journal of the American Veterinary Medical Association

shadowing were found in the left middle portion of the abdomen. The larger mass was 9.5 cm in diameter, and the smaller mass was 4.7 cm in diameter. The masses extended from the hilus of the spleen and had similar echogenicity and shape to that of multiple

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in Journal of the American Veterinary Medical Association

also slight irregularity of the caudoventral margins of the liver, and rounding of the head and possibly the body of the spleen is present. Increased width and opacity in the region of the caudal mediastinum can also be seen. Based on these findings

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether a group of 3 genetic differences in the nonstructural protein (NS1) or 1 genetic difference in the structural protein (VP2) of Aleutian disease parvovirus (ADV) is responsible for an increase in the in vivo replication and pathogenicity of G/U-8, a chimera of ADV-G (nonpathogenic) and ADVUtah (pathogenic), compared with G/U-10.

Animals—32 eight-month-old female sapphire mink (Mustela vison).

Procedure—Chimeric viruses were constructed, propagated in vitro, and used to inoculate mink. Antiviral antibody responses, presence of serum viral nucleic acid, and serum gamma globulin concentrations were monitored for 120 days following inoculation. Histologic examination of the liver, kidneys, spleen, and mesenteric lymph nodes was performed after necropsy.

Results—A chimera containing only the 3 amino acid substitutions in NS1 did not elicit measurable responses indicative of replication or pathogenicity in inoculated mink. Serum antiviral antibody responses, frequency of detection of viral nucleic acid in serum, gamma globulin response, and histologic changes in mink inoculated with chimeras containing a valine residue at codon 352 (352V) of VP2 capsid were increased, compared with values from mink inoculated with chimeric viruses that did not contain 352V.

Conclusion and Clinical Relevance—A valine residue at codon 352 in the VP2 capsid protein of ADV affects in vivo viral replication and pathogenicity. This amino acid may be part of an incompletely defined pathogenic determinant of ADV. Further characterization of the pathogenic determinant may allow future development of focused preventive and therapeutic interventions for Aleutian disease of mink. (Am J Vet Res 2001;62:1658–1663)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate cyclooxygenase isozyme distribution in tissues from dogs and determine the differential sensitivity of canine cyclooxygenase (COX)-1 and -2 isozymes to nonsteroidal anti-inflammatory drugs (NSAIDs).

Sample Population—Canine tissue samples (stomach, duodenum, ileum, jejunum, colon, spleen, cerebral cortex, lung, ovary, kidney, and liver) were obtained from 2 dogs for northern and western blot analyses, and blood for whole blood COX assays was obtained from 15 dogs.

Procedure—11 NSAIDs were evaluated to determine their COX-2 selectivity in whole blood assays. The concentrations of the drug needed to inhibit 50% of enzyme activity (IC50) were then calculated for comparison. Expression and tissue distribution of COX isozymes were determined by northern and western blot analysis.

Results—Aspirin, diclofenac, indomethacin, ketoprofen, meclofenamic acid, and piroxicam had little selectivity toward COX isozymes, whereas NS398, carprofen, tolfenamic acid, nimesulide, and etodolac had more than 5 times greater preference for inhibiting COX-2 than COX-1. All canine tissues examined, including those from the gastrointestinal tract, coexpressed COX-1 and -2 mRNA, although protein expression was observed only for COX-1.

Conclusions and Clinical Relevance—Canine COX-2 was selectively inhibited by etodolac, nimesulide, and NS398; tolfenamic acid and carprofen also appeared to be preferential COX-2 inhibitors in dogs. The roles of COX-1 as a constitutive housekeeping enzyme and COX-2 as a proinflammatory inducible enzyme (as determined in humans) appear to apply to dogs; therefore, COX-2-selective inhibitors should prove useful in reducing the adverse effects associated with nonselective NSAIDs. (Am J Vet Res 2004;65:810–818)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of continuous low-dose infusion of lipopolysaccharide (LPS) on the expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1) mRNA and neutrophil accumulation in the lungs, liver, spleen, small intestine, and pancreas in dogs.

Animals—11 healthy adult Beagles.

Procedure—Dogs received a continuous infusion of a low dose (10 µg/kg/h, IV) of LPS ( Escherichia coli055:B5) or saline (0.9% NaCl) solution (20 mL/kg/h, IV) for 8 hours. Activity levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) and the number of WBCs in circulation were examined before and 1, 2, 4, and 8 hours after the onset of LPS infusion. Expression of E-selectin and ICAM-1 mRNA and the number of neutrophils in each tissue were examined.

Results—After the onset of LPS infusion, serum TNF-α and IL-1β activities transiently increased. Thereafter, IL-6 activity increased, and high IL-6 activity was maintained throughout the experiment. In dogs in the LPS group, expression of E-selectin mRNA increased only in the lungs, and expression of ICAM-1 mRNA increased in the lungs and liver; the number of neutrophils in the tissue increased in the lungs and liver.

Conclusions and Clinical Relevance—Results suggested that expression of E-selectin and ICAM-1 mRNA increased during sepsis, particularly in the lungs and liver, and that this increase was associated with neutrophil accumulation. Hence, inhibiting the activation of endothelial cells in the lung and liver may decrease organ damage caused by accumulated neutrophils and help regulate multiple-organ dysfunction. (Am J Vet Res 2005;66:1259–1266)

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in American Journal of Veterinary Research

Abstract

Objective—To characterize clinical and hematologic responses in dogs following experimental inoculation with Babesia gibsoni-like isolates from infected dogs in Oklahoma.

Design—Prospective study.

Animals—6 mixed-breed dogs.

Procedure—2 dogs were inoculated with organisms from a naturally infected dog, and 3 were inoculated with organisms from a second naturally infected dog (1 of these 3 dogs was splenectomized 1 week prior to inoculation). One dog was not inoculated. Complete blood counts were performed weekly.

Results—In the 5 dogs inoculated with organisms, parasites were initially detected 1 to 5 weeks after inoculation, and severity of parasitemia peaked with 1.9 to 6.0% of RBC infected by 4 to 6 weeks after inoculation. Parasitemia was easily detectable (> 0.1% of RBC infected) for 3 to 4 weeks. Clinical abnormalities included lethargy, fever, and pale mucous membranes but were mild to nearly inapparent in 2 dogs. All dogs developed regenerative anemia and marked thrombocytopenia. Thrombocytopenia developed before and lasted longer than the parasitemia. Profound but transient neutropenia was detected in some dogs. The splenectomized dog developed more severe parasitemia and anemia and more pronounced clinical abnormalities. Three dogs with intact spleens recovered without treatment.

Conclusions and Clinical Relevance—Results suggest that 2 or more genotypically distinct, but morphologically identical, small Babesia parasites can infect dogs in the United States. Compared with infection with small Babesia parasites from California, infection with these isolates resulted in less severe parasitemia and clinical abnormalities. Parasitemia was transient, indicating that identification of organisms in blood smears may be difficult in some dogs. (J Am Vet Med Assoc 2002;220:185–189)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the efficacy (durations of remission and survival) of an alternating-day radiation protocol for incompletely excised histologic grade-III solitary mast cell tumors (MCTs) in dogs.

Design—Retrospective study.

Animals—31 dogs.

Procedure—Radiation (52 Gy in an 18-fraction alternating-day protocol) was delivered to an area bordered by margins ≥ 3 cm around the surgical scar and to the associated local-regional lymph nodes. Dogs were not given chemotherapeutic agents concurrently or after radiation. Information on signalment, duration of remission, and survival time was obtained from medical records.

Results—Median and mean durations of remission were 27.7 and 17.0 months, respectively (range, 1 to 47 months). Median and mean durations of survival were 28 and 20 months, respectively (range, 3 to 52 months). Dogs with tumors located on the skin of the pinna, perineum, and prepuce had a median duration of remission greater than dogs with tumors located at other sites (27.7 and 14.4 months, respectively). Dogs with tumors ≤ 3 cm in maximum diameter before surgery survived longer than dogs with tumors > 3 cm (31 and 24 months, respectively). The remission rate was 65% and survival rate was 71% at 1 year after treatment. Sixteen dogs that were euthanatized had complications associated with local-regional tumor progression. Systemic metastases to liver, spleen, intestine, and bone marrow were detected in 1 dog.

Conclusions and Clinical Relevance—Without further treatment, incompletely excised grade-III mast cell tumors have high local-regional recurrence; local-regional treatment with radiation may effectively be used to manage many such tumors. (J Am Vet Med Assoc 2004;224:79–82)

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in Journal of the American Veterinary Medical Association

Summary:

Eight of 19 calves born to bovine viral diarrhea virus (bvdv)-negative and -immunocompetent dams were determined to be infected with a noncytopathic strain of bvdv. Six of the 8 calves had diarrhea and 2 had no clinical signs of disease. In 3 euthanatized calves, lesions consistent with mucosal disease were found throughout the gastrointestinal tract, and the virus was isolated from the spleen, lymph nodes, and small intestine. In 5 calves, bvdv was isolated from mononuclear cells in blood samples obtained 21 days apart, indicating persistent infection. The virus was not isolated from sera obtained from 2 calves, with chronic nonclinical infections, that had neutralizing antibody titers ≥ 1:512 against bovine viral diarrhea-Singer virus and titers ≥ 1:256 against the persistent bvdv. Twenty-one days after vaccination with a vaccine that contained inactivated noncytopathic and cytopathic biotypes of bvdv, 4 of 5 persistently infected calves had neutralizing antibody titers ≤ 1:4 against the bovine viral diarrhea-Singer virus and their persistent virus. Prior to vaccination, 2 of 11 virus-negative calves had neutralizing antibody titers ≤ 1:128 against the bovine viral diarrhea-Singer virus, and after vaccination, only 1 virus-negative calf had a titer ≤ 1:512. At 149 days after revaccination and prior to weaning, 4 virus-negative calves had neutralizing antibody titers ≤ 1:512 (range, 1:16 to 1:384). Under the specific conditions in this herd, we were not able to detect a beneficial effect of vaccination. Colostral origin bvdv-specific antibody, capable of neutralizing the persistently infective bvdv strain, most likely interfered with isolation of the virus from the sera of 2 persistently infected calves.

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in Journal of the American Veterinary Medical Association