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  • Author or Editor: Autumn P. Davidson x
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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate and compare the in vitro antifungal properties of lufenuron and nikkomycin Z against isolates of Coccidioides immitis and Aspergillus fumigatus when used singly and in combination with the azole antifungal agent itraconazole.

Sample Population—3 clinical isolates of A fumigatus and the Silveira strain of C immitis.

Procedure—The fungal isolates were tested in vitro for susceptibility to the single and combination of compounds by use of microtiter-format susceptibility methods. Minimum inhibitory concentration end points were determined visually, and the contents of representative wells were examined microscopically for evidence of morphologic effects on fungi.

Results—No evidence of inhibition, either by susceptibility testing or direct microscopic examination of treated cells, was obtained with lufenuron under experimental conditions. In contrast, nikkomycin Z, a known inhibitor of fungal chitin synthesis, had potent activity against C immitis when used singly. A synergistic interaction between nikkomycin Z and itraconazole was found against isolates of both species tested.

Conclusions and Clinical Relevance—On the basis of our in vitro data, lufenuron does not appear to possess antifungal properties. ( Am J Vet Res 2005;66:1090–1093)

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in American Journal of Veterinary Research

Abstract

Objective—To quantify inheritance of tricuspid valve dysplasia (TVD) in a population of Labrador Retrievers and evaluate the possibility of the effect of a major locus on TVD.

Animals—521 Labrador Retrievers (345 with known phenotypes and 176 related dogs with unknown phenotypes).

Procedure—Dogs were considered normal, equivocal, and affected for TVD on the basis of echocardiographic appearance of the tricuspid valves. Information on related dogs was collected for estimation of heritability of the 3 categories of phenotype, using a threshold model. Complex segregation analysis was performed to evaluate the possibility of the effect of a major locus on TVD.

Results—Heritability of TVD in this population of dogs was found to be 0.71, a value sufficiently large to suggest a segregating major locus. Subsequent complex segregation analysis did not provide sufficiently strong evidence to indicate influence of a major locus on the prevalence of TVD. However, complex segregation analysis for 2 categories of phenotype (eg, equivocal dogs were grouped with affected dogs) suggested that there was a single recessive allele with a substantial impact on the expression of TVD.

Conclusion and Clinical Relevance—In Labrador Retrievers, TVD is a heritable disorder. Affected dogs and dogs closely related to affected dogs should not be used for breeding. There was insufficient evidence to suggest the influence of a major locus on TVD, although this conclusion was affected by the classification of dogs for diagnosis of the condition. (Am J Vet Res 2002;63:816–820)

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in American Journal of Veterinary Research

Abstract

Objective—To determine clinical, clinicopathologic, and radiographic abnormalities in dogs with coccidioidomycosis.

Design—Retrospective case series.

Animals—24 dogs.

Procedure—Clinical information and results of clinicopathologic testing were obtained from medical records. Thoracic radiographs were reviewed to characterize abnormalities.

Results—Dogs ranged from 1 to 10 years old at the time of diagnosis, with 12 dogs being between 1 and 3 years old. Historical complaints included cough, lameness, signs of head or neck pain, and difficulty breathing. Mild anemia, neutrophilia, and monocytosis were common. All dogs had hypoalbuminemia, and 8 of 15 had hyperglobulinemia. Thoracic radiographs of 19 dogs were reviewed. Pulmonary infiltrates were seen in 13 dogs, with an interstitial pattern of infiltration being most common. Hilar lymphadenopathy was seen radiographically in 10 dogs. Serum from 20 dogs was tested for antibodies against Coccidioides immitis. One dog was positive for IgM antibodies, 5 were positive for IgM and IgG antibodies, and 14 were positive for IgG antibodies. Quantitative IgG titers measured in 14 dogs ranged from 1:2 to 1:128 (median and mode, 1:32). In 6 dogs, histologic examination of biopsy samples revealed fungal spherules ranging from 8 to 70 μm in diameter.

Conclusions and Clinical Relevance—Results suggest that in dogs, coccidioidomycosis may be associated with a wide spectrum of nonspecific respiratory and musculoskeletal abnormalities. The chronic nature of the disease makes diagnosis difficult, even in regions in which the organism is endemic. (J Am Vet Med Assoc 2003;222:461–466)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine ultrasonographic characteristics of the thyroid gland in healthy small-, medium-, and large-breed dogs and evaluate the relationships of thyroid gland size and volume with body weight and body surface area (BSA).

Animals—72 dogs of small (6 Toy and 6 Miniature Poodles), medium (12 Beagles), and large breeds (12 Akitas and 36 Golden Retrievers).

Procedure—Each dog's thyroid gland was examined ultrasonographically with a 10- to 5-MHz multifrequency linear-array transducer. Size, shape, echogenicity, and homogeneity of thyroid lobes were evaluated on longitudinal and transverse images. Thyroid lobe volume was estimated by use of the equation for an ellipsoid (π/6 [length × height × width]).

Results—Thyroid lobes appeared fusiform or elliptical on longitudinal images and triangular or round to oval on transverse images. In most dogs, thyroid lobes were hyperechoic or isoechoic, compared with surrounding musculature, and had a homogeneous echogenic pattern. Mean length, width, height, and volume of thyroid lobes were significantly greater in Akitas and Golden Retrievers, compared with findings in Beagles or Poodles; mean length, width, and height were significantly greater in Beagles, compared with findings in Poodles. Total thyroid gland volume correlated with body weight (r = 0.73) and BSA (r = 0.74).

Conclusions and Clinical Relevance—Among the dog breeds examined ultrasonographically, thyroid lobe size and volume were more variable than shape, echogenicity, and homogeneity. The correlation of thyroid gland volume with BSA suggests that size of the dog, rather than breed, should be considered when assessing thyroid glands ultrasonographically.

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in American Journal of Veterinary Research

Abstract

Objective—To characterize a genetic component to cricopharyngeal dysfunction (CD) in Golden Retrievers.

Animals—117 dogs.

Procedure—The CD phenotype was determined by videofluoroscopy, and dogs were classified as affected if the upper esophageal sphincter (UES) did not open, if there were morphologic abnormalities of the UES, or if opening of the UES was delayed for ≥ 6 videofluoroscopic frames (0.2 seconds) after closure of the epiglottis. All survey radiographic and videofluoroscopic studies were reviewed by the same radiologist.

Results—Of the 117 dogs (47 males and 70 females) with a CD phenotype determined via videofluoroscopy, 21 dogs (18.0%) had abnormalities of the UES (affected). Of these 21 dogs, 9 were males (19.1% of all males) and 12 were females (17.1% of all females). The heritability of CD in a threshold model was estimated as 0.61, which established that CD could be passed from parent to offspring. Results of complex segregation analysis suggested that a single recessive allele of large effect contributed to the expression of this disease in Golden Retrievers.

Conclusions and Clinical Relevance—The determination that CD is inherited in Golden Retrievers is an important step in providing information for veterinarians attending dogs with this disorder. Breeders also require this information to make informed breeding decisions. ( Am J Vet Res 2004;65:344–349)

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in American Journal of Veterinary Research

Abstract

Objective—To determine concentrations of 17α-hydroxyprogesterone (17OHP) in serum of healthy bitches during various stages of the reproductive cycle and in bitches with hyperadrenocorticism and to compare the dynamics of 17OHP with those of progesterone.

Design—Prospective evaluation study.

Animals—15 healthy sexually intact bitches and 28 spayed bitches with hyperadrenocorticism.

Procedures—11 healthy bitches were evaluated during estrus, nonpregnant diestrus, and anestrus (group 1); 4 other healthy bitches were evaluated during pregnancy and after ovariohysterectomy (group 2). Cycle stages were determined via physical examination, vaginal cytologic evaluation, and serum progesterone concentration. Bitches with hyperadrenocorticism were evaluated once at the time of diagnosis (group 3). Serum hormone concentrations were determined with immunoassays.

Results—In group 1, the serum 17OHP concentration was significantly higher in diestrus (median, 1.8 ng/mL) than in estrus (median, 1.1 ng/mL) and anestrus (median, 0.2 ng/mL) and higher in estrus than in anestrus. Changes in serum progesterone concentrations accounted for 22% (estrus) or 23% (diestrus) of the variation in serum 17OHP concentrations. In group 2, 17OHP and progesterone concentrations were significantly higher during pregnancy than after ovariohysterectomy. The serum 17OHP concentration in group 3 was significantly lower (median, 0.2 ng/mL) than in group 1 in estrus and diestrus and in group 2 during pregnancy (median, 0.7 ng/mL) but was not different from 17OHP concentrations in anestrus or after ovariohysterectomy (median, 0.2 ng/mL).

Conclusions and Clinical Relevance—Serum 17OHP concentrations in healthy bitches increased during estrus, diestrus, and pregnancy and at those times were higher than in spayed bitches with hyperadrenocorticism.

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in Journal of the American Veterinary Medical Association