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  • Author or Editor: J. Robert Duncan x
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Summary

A semiquantitative heartworm test of antigen concentration was evaluated as a predictor of thromboembolism after adulticide treatment. Seventeen dogs with naturally acquired infections of Dirofilaria immitis (heartworms) were studied before and after thiacetarsamide treatment, using physical examinations, arterial blood gas analyses, thoracic radiography, and pulmonary hemodynamic and arteriographic tests. Eight dogs were considered to have a low burden of heartworms and 9 had a high burden. Dogs with a high worm burden had more severe pulmonary thromboembolism with pulmonary hypertension, dilated pulmonary arteries, flow obstruction of the caudal pulmonary arteries, and parenchymal lesions in the caudal lung lobes. Dogs with a low worm burden had minimal changes. Within each group of dogs, the severity of thromboembolism was less in some dogs in which all heartworms were not killed. Six of the 9 dogs with a high burden of heartworms had surviving heartworms, and 1 of these dogs had 38 live heartworms. Only 4 of the 8 dogs with a low worm burden had complete heartworm mortality, but only 1 dog had more than 3 surviving heartworms. We concluded that dogs with a high worm burden were more likely to have pulmonary thromboembolism after thiacetarsamide treatment and that dogs with a low worm burden were more likely to have minimal changes. A semiquantitative heartworm test of antigen concentration is recommended as part of the pretreatment evaluation of dogs infected with heartworms.

Free access
in American Journal of Veterinary Research

Summary

The severity of pulmonary thromboembolism and pulmonary hypertension induced by heartworms dying after administration of 2 adulticides was evaluated. Because melarsomine dihydrochloride (RM340) has been shown to be more effective in killing Dirofilaria immitis (heartworms) than the traditional approved adulticide, thiacetarsamide, an attempt was made to determine whether this new adulticide induced more severe lung disease. Before adulticide treatment, 32 dogs with naturally acquired heartworm infections received physical examinations, semiquantitative antigen concentration tests, cbc, platelet counts, serum biochemistry analyses, arterial blood gas determinations, thoracic radiography, pulmonary arteriography, and pulmonary hemodynamic tests. Eight dogs with a low burden and 9 dogs with a high burden of heartworms were treated with thiacetarsamide, and 7 dogs with a low burden and 8 dogs with a high burden were treated with RM340. Except for the heartworm-burden test, tests were repeated at regular intervals during the first 7 weeks after treatment. None of the dogs coughed or had dyspnea after treatment. Six of 9 dogs with high worm burdens and 4 of 8 dogs with low worm burdens had surviving heartworms after thiacetarsamide treatment, in contrast to only 3 of 15 RM340-treated dogs. Differences between the 2 adulticide treatments were minimal as determined by thoracic radiography, pulmonary hemodynamic tests, clinical laboratory analyses, pulmonary arteriography, or necropsy. The RM340 treatment was a more effective adulticide, but it did not increase the severity of hypertension and thromboembolism.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine effects of cyclophotocoagulation via administration of 100 J with a neodymium: yttrium aluminum garnet (Nd:YAG) laser on corneal touch threshold (CTT), intraocular pressure (IOP), aqueous tear production, and corneal nerve morphology in eyes of dogs.

Animals—15 dogs.

Procedure—Noncontact Nd:YAG laser was transsclerally applied (10 applications; 25 W for 0.1 seconds for each application to each of 4 quadrants) to the ciliary body of the left eye of 15 dogs; the right eye was the control eye. Corneal integrity, CTT, tear production as measured by the Schirmer tear test (STT), and IOP were evaluated for 14 days following laser treatment. On day 14, dogs were euthanatized, eyes harvested, and corneas stained with gold chloride. Major nerve bundles were analyzed by use of a drawing tube attached to a light microscope, and maximum diameters were measured by use of image analysis software.

Results—All laser-treated eyes had significantly higher CTT values, compared with control eyes. Six of 15 laser-treated eyes developed ulcerative keratitis. On most days, IOP was significantly lower in laser-treated eyes in both morning and evening. Laser-treated eyes had a significant decrease of approximately 1 nerve bundle/corneal quadrant. Values for STT or nerve bundle diameters did not differ significantly.

Conclusion and Clinical Relevance—Administration of 100 J with a Nd:YAG laser effectively reduced IOP while increasing CTT and caused a significant decrease in number, but not diameter, of major corneal nerve bundles. Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation. (Am J Vet Res 2002;63:906–915)

Full access
in American Journal of Veterinary Research

Abstract

Case Description—1 dog evaluated because of inappetence and lameness of the left hind limb of 1 day's duration and 1 dog evaluated because of inappetence, fever, and lymphadenopathy of 2 weeks' duration.

Clinical Findings—Histologic examination of excisional biopsy specimens from lymph nodes revealed pyogranulomatous lymphadenitis in both dogs. Quantitative real-time PCR assays detected Bartonella henselae DNA in blood samples and affected lymph node specimens from both dogs. Antibodies against B henselae were not detected via immunofluorescent antibody testing during active disease in either dog.

Treatment and Outcome—1 dog recovered after 6 weeks of treatment with doxycycline (5 mg/kg [2.3 mg/lb], PO, q 12 h), whereas the other dog recovered after receiving a combination of azithromycin (14.5 mg/kg [6.6 mg/lb], PO, q 24 h for 21 days), doxycycline (17.3 mg/kg [7.9 mg/lb], PO, q 24 h for 4 weeks), and immunosuppressive corticosteroid (prednisone [3 mg/kg {1.4 mg/lb}, PO, q 24 h], tapered by decreasing the daily dose by 25% every 2 weeks) treatment.

Clinical RelevanceB henselae is implicated as a possible cause or a cofactor in the development of pyogranulomatous lymphadenitis in dogs. In dogs with pyogranulomatous lymphadenitis, immunofluorescent assays may not detect antibodies against B henselae. Molecular testing, including PCR assay of affected tissues, may provide an alternative diagnostic method for detection of B henselae DNA in pyogranulomatous lymph nodes.

Full access
in Journal of the American Veterinary Medical Association

Summary

Four diets were formulated to contain: 16% protein and 0.4% phosphorus–diet 1; 16% protein and 1.4% phosphorus– diet 2; 32% protein and 0.4% phosphorus–diet 3; and 32% protein and 1.4% phosphorus–diet 4. Forty-eight dogs were fed diet 1 for 3 months after surgical reduction of renal mass, then were allotted to 4 groups of 12 dogs each, with equal mean values for glomerular filtration rate (gfr). Dog of groups 1–4 were fed diets 1–4, respectively, for 24 months. Data collected from the dogs during and at termination of the study were analyzed statistically for effects of dietary protein, phosphorus (P), time, and interactions between these factors.

During the 24 months of study, 24 dogs developed uremia and were euthanatized for necropsy. Necropsy also was performed on the remaining 24 dogs after they were euthanatized at the end of the study. Dog survival was significantly enhanced by 0.4% P diets (vs 1.4% P diets), but survival was not significantly influenced by amount of dietary protein. The 0.4% P diets (vs 1.4% P diets) significantly increased the period that gfr remained stable before it decreased, but dietary protein did not have significant effect.

Significant blood biochemical changes attributed to P, protein, and time were identified during the study. Terminally, plasma parathyroid hormone concentration was significantly increased from prediet values in all groups of dogs.

Urine protein excretion was not significantly affected by dietary amount of either protein or P, when measured by either timed urine collection or urine protein-to-creatinine ratio. A tendency was seen for increased protein excretion with passage of time.

Histologic and mineral analyses of kidneys removed at necropsy revealed some significant difference attributable to diet, but differences were more marked when diet was ignored, and the 24 surviving dogs were compared with the 24 that developed uremia.

Overall, amount of dietary P was more important than amount of dietary protein for preventing adverse responses. However, because renal damage specifically attributable to either dietary component was not obvious, it is possible that the effects of P were manifested by extrarenal mechanisms.

Free access
in American Journal of Veterinary Research

Summary

Twenty-four dogs with induced, severe chronic renal failure were allotted to 2 groups of 12 each. Group-A dogs were fed a 0.4% phosphorus (P)/0.6% calcium, 32% protein diet, and group-B dogs were fed a 1.4% P/l.9% calcium, 32% protein diet. Dogs were studied over 24 months to determine clinical status, survival, blood biochemical alterations, glomerular filtration rate (gfr), urinary excretion of P and protein, renal morphologic changes, and renal tissue concentrations of calcium, P, and magnesium.

Group-A dogs developed statistically significant differences from group-B dogs in several blood biochemical values (pcv and total solids, calcium, P, potassium, sodium, chlonde, total CO2 (TCO2), anion gap, and parathyroid hormone concentrations) and in urinary P excretion.

Mean ( ± sem) gfr values in group-A and group-B dogs were nearly identical when diets were initiated (group _A = 0.73 ± 0.05 ml/min/kg of body weight; group B = 0.72 ± 0.08 ml/min/kg), but significantly (P = 0.0346) lower gfr developed in group-B than in group-A dogs over time. At 24 months, gfr in survivors was 0.83 ± 0.08 and 0.63 ± 0.15 ml/min/kg for dogs of groups A and B, respectively.

Other measurements favored the hypothesis that P/calcium restriction was beneficial, but values failed to reach statistical significance. Survival was greater at 24 months in group-A than in group-B (7 vs 5) dogs, and renal tissue concentrations of calcium and P were higher in group-B than in group-A dogs.

Differences were not detected between groups in urinary excretion of protein and in the type or severity of renal lesions.

We conclude that P/calcium restriction at 32% protein intake is beneficial to dogs with chronic renal failure, but that the degree of restriction imposed in group-A dogs of this study did not prevent development of abnormalities. Factors other than dietary P/calcium intake may have a role in progression of renal failure to uremia.

Free access
in American Journal of Veterinary Research