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Abstract

Objective—To characterize the effect of maintenance hemodialysis on plasma amino acid concentrations and to quantitate free amino acid losses into the dialysate during hemodialysis in healthy dogs.

Animals—8 healthy adult dogs.

Procedure—Five dogs received hemodialysis treatments 3 times per week for 4 weeks. Plasma amino acid concentrations were evaluated once per week for 4 weeks in each of the 5 dogs prior to hemodialysis (time 0), 90 minutes during hemodialysis, and immediately after hemodialysis (180 minutes). Total free amino acid concentrations and plasma amino acid concentrations (time 0, 90 minutes, and 180 minutes) in the dialysate were evaluated in 3 dogs that received 1 hemodialysis treatment.

Results—Significant time versus week interactions with any plasma amino acid were not detected; however, significant decreases in all plasma amino acid concentrations measured were detected at the midpoint of dialysis (46 ± 2%) and at the end of each dialysis session (38 ± 2%). Mean (± SEM) total free amino acid loss into the dialysate was 2.7 ± 0.2 g or 0.12 g/kg of body weight.

Conclusions and Clinical Relevance—Hemodialysis is associated with significant alterations in plasma amino acid concentrations and loss of free amino acids into the dialysate. Loss of amino acids into the dialysate, coupled with protein calorie malnutrition in uremic patients, may contribute to depletion of amino acid stores.(Am J Vet Res 2000;61:869–873)

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in American Journal of Veterinary Research

Abstract

Objective—To compare efficacy and safety of meso- 2,3-dimercaptosuccinic acid (DMSA) and Ca EDTA for treatment of experimentally induced lead toxicosis in cockatiels ( Nymphicus hollandicus).

Animals—137 (69 females, 68 males) healthy cockatiels between 6 months and 8 years old.

Procedure—Lead toxicosis was induced by placing lead shot in the gastrointestinal tract. Treatment with Ca EDTA (40 mg/kg of body weight, IM, q 12 h), DMSA (40 or 80 mg/kg, PO, q 12 h), and sodium sulfate salts (SSS; 0.5 mg/kg, PO, q 48 h) was initiated 4 days after induction of lead toxicosis. Blood lead concentrations were determined, using atomic absorption spectrophotometry. Number of birds surviving and blood lead concentrations were compared among groups.

Results—In Phase II of the study, administration of DMSA and Ca EDTA significantly decreased blood lead concentrations when used alone or in combination in birds with lead toxicosis. Addition of SSS did not result in further decreases in lead concentrations. Eight of 12 (66.7%) birds without lead toxicosis given 80 mg of DMSA/kg did not survive to the end of the study . Lesions related to treatment with chelating agents were not detected during necropsy.

Conclusions and Clinical Relevance—DMSA and Ca EDTA are effective chelating agents in cockatiels. Because DMSA is administered orally, it may be easier than other chelating agents for bird owners to administer at home. However, the narrow margin of safety of DMSA indicates that this agent should be used with caution. (Am J Vet Res 2000;61:935–940)

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in American Journal of Veterinary Research

Abstract

Objective—To develop a model for measuring rotary stability of the canine elbow joint and to evaluate the relative contribution of the anconeal process (AN), lateral collateral ligament (LCL), and medial collateral ligament (MCL).

Sample Population—18 forelimbs from 12 canine cadavers.

Procedure—Forelimbs were allocated to 3 experimental groups (6 forelimbs/group). Each intact forelimb was placed in extension at an angle of 135° and cycled 50 times from –16° (pronation) to +28° (supination) in a continuous manner at 2.0 Hz. Cycling was repeated following sectioning of the structure of interest (group 1, AN; group 2, LCL; and group 3, MCL). Torque at –12° (pronation) and +18° (supination) was measured for each intact and experimentally sectioned limb. A Student t test was performed to compare torque values obtained from intact verses experimentally sectioned limbs and for comparison with established criteria for differentiation of primary (≥ 33%), secondary (10 to 33%), and tertiary rotational stabilizers (< 10%).

Results—In pronation, the AN was the only primary stabilizer (65%). For supination, the LCL was a primary stabilizer (48%), AN was a secondary stabilizer (24%), and MCL was a tertiary stabilizer (7%).

Conclusions and Clinical Relevance—With the elbow joint in extension at an angle of 135°, the AN is a primary rotational stabilizer in pronation, and the LCL is a primary stabilizer in supination. Disruption of the AN or LCL may affect rotary range of motion or compromise stability of the elbow joint in dogs. (Am J Vet Res 2002;63:1520–1526)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the prevalence of activating internal tandem duplications (ITDs) in exons 11 and 12 of c-kit in mast cell tumors (MCTs) of dogs and to correlate these mutations with prognosis.

Sample Population—157 formalin-fixed, paraffinembedded MCTs from dogs in the pathology database of the Veterinary Medical Teaching Hospital at the University of California, Davis.

Procedure—Genomic DNA was isolated from tumor specimens and a polymerase chain reaction procedure was performed to determine whether there were ITDs in exons 11 and 12.

Results—We identified ITDs in 1 of 12 (8%) grade-I, 42 of 119 (35%) grade-II, and 9 of 26 (35%) grade-III tumors (overall prevalence, 52 of 157 [33%]). Logistic regression analysis revealed that the odds of grade-II and -III tumors possessing an ITD were approximately 5 times greater than that for grade-I tumors, although these odds did not differ significantly. Although MCTs possessing an ITD were twice as likely to recur after excision and twice as likely to result in metastasis as those without an ITD, these values also did not differ significantly.

Conclusions and Clinical Relevance—These results provide evidence that ITDs in c-kit occur frequently in MCTs of dogs. The high prevalence of c-kit activating mutations in MCTs of dogs combined with the relative abundance of mast cell disease in dogs provide an ideal naturally developing tumor in which to test the safety and efficacy of novel small-molecule kinase inhibitors such as imatinib mesylate. (Am J Vet Res 2002;63:1718–1723)

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in American Journal of Veterinary Research

Abstract

Objective—To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds.

Animals—16 adult Japanese quail.

Procedure—A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability.

Results—All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed.

Conclusions and Clinical Relevance—Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat selfmutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species. (Am J Vet Res 2004;65:497–502)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the distribution of force between the articular surfaces of the humerus and radius and between the humerus and ulna in normal canine forelimbs.

Sample population—12 cadaveric canine right forelimbs.

Procedure—Transarticular force maps were created by placing a tactile array pressure sensor into the elbow joint cavity and loading cadaveric forelimbs in a materials testing system. Mean joint forces were determined at loads of 50, 100, 150, and 200 N.

Results—All tests produced 2 distinct areas of high load that corresponded with the proximal articular surfaces of the radius and ulna. Mean forces for the radial proximal articular surface were slightly but significantly greater than for the ulna, averaging 51% to 52% of total force for all applied loads.

Conclusions and Clinical Relevance—The proximal articular surface of the ulna contributes substantially to load transfer through the canine elbow joint. Abnormalities, which increase this load, might contribute to canine elbow joint dysplasia, specifically fragmentation of the medial coronoid process and osteochondritis dissecans of the medial aspect of the humeral condyle. In the treatment of these conditions, the normal force distribution within the canine elbow joint should be taken into consideration. (Am J Vet Res 2005;66:132–135)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate orally administered famciclovir for treatment of cats with experimentally induced disease attributable to feline herpesvirus type-1 (FHV-1).

Animals—16 nonvaccinated specific-pathogen-free cats.

Procedures—Cats were treated orally with famciclovir (90 mg/kg; n = 10) or a similar volume of lactose (400 mg; 6) 3 times/d for 21 days. Cats were inoculated with FHV-1 and administered the first treatment dose on day 0. Disease score; weight; results of urinalysis, serum biochemical analysis, and CBC; histologic conjunctivitis score; herpetic DNA shedding; goblet cell density; anti-FHV-1 antibody concentration; and plasma penciclovir concentration were measured.

Results—On days 4 to 18 following inoculation, disease scores were lower in famciclovir-treated cats than in lactose-treated cats. Lactose-treated cats decreased in weight during the first 7 days after inoculation, but famciclovir-treated cats increased in weight throughout the study. Percentage change in weight was greater in famciclovir-treated cats on days 7 and 14 than in lactose-treated cats. Serum globulin concentration was lower on days 3 through 9, conjunctivitis histologic score was lower on day 14, herpetic DNA was shed less frequently throughout the study, goblet cell density was greater on day 21, and circulating anti-FHV-1 antibody concentration at study end was lower in famciclovir-treated cats, compared with these measurements in lactose-treated cats. Approximate peak plasma penciclovir concentration was 2.0 μg/mL.

Conclusions and Clinical Relevance—Famciclovir administration improved outcomes for systemic, ophthalmic, clinicopathologic, virologic, and histologic variables in cats experimentally infected with FHV-1. Adjunctive topical mucinomimetic and antimicrobial treatments may also be necessary.

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effects of 4.7-mg deslorelin acetate implants on egg production and plasma concentrations of 17β-estradiol and androstenedione in Japanese quail (Coturnix coturnix japonica) over 180 days and assess safety of the implants in quail via gross and histologic examination.

Animals—20 female Japanese quail.

Procedures—Following a 7-day period of consistent egg laying, quail were anesthetized and received a 4.7-mg deslorelin implant (treatment group; n = 10) or identical placebo implant (control group; 10) SC between the scapulae. Egg production was monitored daily. Plasma concentrations of 17β-estradiol and androstenedione were measured on days 0 (immediately prior to implant injection), 14, 29, 62, 90, 120, 150, and 180 via radioimmunoassay. Birds were weighed periodically and euthanized at day 180 for complete necropsy.

Results—Egg production was significantly decreased in the treatment group, compared with the control group, from 2 to 12 weeks after implant injection. Egg production ceased in 6 of 10 quail in the treatment group (mean duration of cessation, 70 days). Plasma androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group than in the control group. Plama androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group then in the control group.

Conclusions and Clinical Relevance—4.7-mg deslorelin acetate implants reversibly decreased egg laying for approximately 70 days in most of the Japanese quail evaluated. Further studies evaluating implants containing different concentrations of the drug are needed in quail and other avian species.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To quantitatively and qualitatively compare electroretinography (ERG) recordings in awake, sedated, and anesthetized dogs.

Animals—Six 6-month-old Beagles.

Procedures—A brief ERG protocol for dogs was used. Following 1-minute and subsequent 5-minute dark adaptation, mixed rod-cone responses were recorded bilaterally with a handheld multispecies ERG device with dogs in each of 3 states of consciousness: awake, sedated (dexmedetomidine and butorphanol), and anesthetized (atropine and hydromorphone, followed by propofol and midazolam and anesthetic maintenance with isoflurane). Low- and high-frequency noise levels were quantified via Fourier analysis, and the effect of consciousness state on signal amplitude, implicit time, and noise was analyzed via repeated-measures ANOVA. In addition, 13 veterinary ophthalmologists who were unaware of the dogs’ consciousness states subjectively graded the ERG recording quality, and scores for each tracing were compared.

Results—ERG amplitudes were highest in awake dogs and lowest in anesthetized dogs. Implicit times were shortest in awake dogs and longest in anesthetized dogs. Differences in b-wave amplitudes and a-wave implicit times were significant. Neither low- nor high-frequency noise levels differed significantly among consciousness states. Furthermore, no significant differences were identified among observers’ scores assigned to ERG tracings.

Conclusions and Clinical Relevance—Anesthesia and sedation resulted in significant attenuation and delay of ERG responses in dogs. Chemical restraint of dogs had no consistently significant effect on low- or high-frequency noise levels or on observer perception of signal quality.

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in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of feline herpesvirus type 1 (FHV-1) on tear film breakup time (TFBUT) and Schirmer tear test (STT) values in cats with primary experimental infection and to determine the relationship betweenTFBUT and STT values and conjunctival goblet cell density (GCD).

Sample Population—9 specific-pathogen–free cats of approximately 6 months of age.

Procedures—6 cats were inoculated with FHV-1; 3 control cats were sham inoculated. Clinical and histologic evidence of conjunctivitis and TFBUT, GCD, and STT values were assessed at multiple times until postinoculation day (PID) 29.

Results—In infected cats, mean clinical and histologic conjunctivitis scores peaked at PID 7 and remained above baseline at PID 29. In control cats, these 2 variables did not change from baseline throughout the study. MeanTFBUT declined rapidly in infected cats up to PID 15 and at PID 29 remained less than baseline, less than for control cats, and below refer-ence range values. Mean STT value for infected cats at PID 29 was increased from baseline but was within the reference range and not different from the value for control cats. Mean GCD in infected cats declined precipitously by PID 7 and remained below reference range values at PID 29. Mean GCD in control cats remained unchanged for the duration of the study period.

Conclusions and Clinical Relevance—FHV-1 induced qualitative tear film abnormalities in experimentally infected cats, as measured by TFBUT and GCD. Assessment of TFBUT provided a reasonable clinical estimate of GCD.

Full access
in American Journal of Veterinary Research