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  • Author or Editor: Clinton D. Lothrop Jr x
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Summary

Clinical status, skin biopsy specimens, and endocrine function were evaluated in normal-coated Pomeranians (n = 12) and Pomeranians affected with growth hormone (gh)-responsive dermatosis (n = 7), then were compared with values in mixed-breed dog controls (n = 19). All Pomeranians were clinically normal; however, the Pomeranians with gh-responsive dermatosis had bilateral alopecia and hyperpigmentation of the trunk, caudal portion of the thighs, and ventral neck region.

Skin biopsy specimens from the affected Pomeranians had decreased-to-normal epidermal thickness and follicular atrophy, compared with normal-coated Pomeranians. Numerous elastin fibers were observed in the skin biopsy specimens of unaffected and affected Pomeranians.

Both groups of Pomeranians had normal results of thyrotropin-releasing hormone (trh) and thyrotropin (tsh) response, adrenocorticotropin (acth) stimulation, and dexamethasone suppression testing. There was no significant increase in serum gh concentration in either group of Pomeranians after xylazine or human GH-releasing factor (ghrf) administration, whereas control dogs had significant (P ≤ 0.05) increase in serum gh concentration after administration of either agent.

Baseline plasma acth concentration in unaffected and affected Pomeranians was increased above the normal range (40 to 90 pg/ml). Post-acth administration serum progesterone, 17-hydroxyprogesterone, and androgen (dehydroepiandrosterone sulfate or androstenedione) concentrations were consistently high in unaffected and affected Pomeranians, compared with values in control dogs.

High baseline plasma acth concentration and increased production of progesterone, 17-hydroxyprogesterone, and dehydroepiandrosterone sulfate or androstenedione after acth administration suggested disregulation of adrenocortical hormone synthesis in both groups of Pomeranians, possibly attributable to partial deficiency of the 21-hydroxylase enzyme. Although all 3 treated dogs developed normal coat in response to supplementation with human gh, gh-responsive dermatosis in Pomeranians may not be entirely attributable to hyposomatotropism, but may also involve adrenocortical hyperprogestinism and/or hyperandrogenism.

Free access
in Journal of the American Veterinary Medical Association

Summary

Pyruvate kinase (pk) deficiency is an autosomal, recessive, inherited disease of Basenjis that causes chronic, regenerative, hemolytic anemia. Diagnostic methods currently used to identify carrier animals rely on measurement of erythrocyte pk activity and frequently give equivocal results. A genetic test incorporating polymerase chain reaction amplification of genomic dna and restriction fragment length polymorphism has been developed to determine the pk genotype of Basenjis. To determine whether results of this genetic test compared with results of standard tests for pk deficiency, erythrocyte pk activity, hematocrit, and reticulocyte counts were determined in, and the genetic test was performed on, 24 dogs. The genetic test accurately identified the 11 dogs whose pk genotype was known prior to this study, and results were consistent with results of measuring erythrocyte pk activity in the remaining 13 dogs. The genetic test may be of value in determining pk genotype of Basenjis.

Free access
in Journal of the American Veterinary Medical Association

Summary

Plasma von Willebrand factor antigen concentration was determined in 15 dogs with suspected hypothyroidism, in 1 dog with hyperthyroidism, and in 14 euthyroid dogs. The mean ± sem von Willebrand factor:antigen concentration in hypothyroid dogs (47.1% ± 12.6%) was significantly decreased (P <0.0005), compared with that in euthyroid dogs (94.7 ± 5.6%). Four hypothyroid dogs were given thyroxine for 1 month and all 4 had an increase in von Willebrand factor:antigen concentration. The plasma von Willebrand factor:antigen concentration was 200% in the hyperthyroid dog. Seemingly, reduced concentrations of plasma von Willebrand factor:antigen can be found in dogs in association with congenital von Willebrand disease or with von Willebrand disease acquired through hypothyroidism.

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in Journal of the American Veterinary Medical Association

SUMMARY

Plasma cortisol and corticosterone responses of 8 clinically normal adult ferrets to synthetic acth (cosyntropin) were evaluated. Cosyntropin was administered iv at 4 dosages (0.5, 1.0, 5.0, and 10 μg/ kg of body weight) at 2- to 4-week intervals, with blood samples collected 60 and 120 minutes after injection. After completion of the studies, an additional acth stimulation test was performed by administering cosyntropin (1.0 μg/kg) im. The baseline plasma cortisol concentrations from all studies ranged from 25.9 to 235 nmol/L (mean ± sem = 73.8 ± 7.0 nmol/L), and plasma corticosterone values ranged from 1.7 to 47 nmol/L (mean ± sem = 8.3 ± 1.1 nmol/L). After iv administration of cosyntropin, plasma concentrations of cortisol and corticosterone increased significantly (P ≤ 0.05) and reached peak values at 60 minutes; however, there were no significant differences between plasma cortisol or corticosterone responses to the 4 dosages of cosyntropin. Intramuscular administration of 1.0 μg of cosyntropin/kg induced increases in plasma cortisol and corticosterone concentrations that were similar to the responses induced by iv administration of cosyntropin. The mean molar ratio of cortisol to corticosterone, calculated from the resting plasma concentrations, was approximately 9:1, whereas the acth-stimulated cortisol to corticosterone ratio was approximately 4:1. Results of this study indicated that administration of cosyntropin to clinically normal ferrets, at dosages ranging from 0.5 to 10 μg/kg, increased plasma concentrations of cortisol and corticosterone. Although cosyntropin stimulates the adrenocortical secretion of cortisol and corticosterone, cortisol appears to be the predominate circulating glucocorticoid in ferrets.

Free access
in American Journal of Veterinary Research

SUMMARY

The beige (bgJ/bgJ) mouse is a well-described murine model of Chediak-Higashi syndrome. Platelet function was examined in normal and beige mice to better characterize the defective aggregation response in platelets from mice with Chediak-Higashi syndrome. Platelet aggregation after collagen, thrombin, and phorbol-12-myristate 13-acetate stimulation was significantly (P < 0.025) decreased in platelets from beige mice, relative to platelets from normal mice. Compared with beige and normal mice, those heterozygous for the bg trait had intermediate responses to collagen and thrombin, but not phorbol-12-myristate 13-acetate. The defect(s) in aggregation of platelets from beige mice was associated with a dense granule storage pool deficiency and decreased stores of serotonin and adenine nucleotides in platelets. Mice heterozygous for the bg trait had normal platelet serotonin and adenine nucleotide concentrations. Platelets from beige mice were approximately 10 times more sensitive to prostacyclin inhibition of collagen-induced aggregation than were platelets from control mice. However, a significant difference in platelet cyclic AMP concentration was not apparent between beige and normal mice after prostacyclin stimulation. Platelet endoperoxide synthesis measured by quantification of thromboxane B2, was normal in beige mice. Protein phosphorylation patterns in mouse platelets were similar to those seen in human platelets. Thrombin and collagen-induced [32P] phosphorylation of 40- and 20-kD proteins in platelets from normal and beige mice was similar. Results indicate that the biochemical defect(s) in platelet function in beige mice is partially attributable to storage pool deficiency and does not result in an absolute defect in phosphorylation of 40- and 20- kD proteins.

Free access
in American Journal of Veterinary Research

Summary

Four German Shepherd Dogs from a litter of 10 were evaluated because of postnatal onset of proportionate growth stunting that clinically resembled well-documented hypopituitary dwarfism in that breed. Although 2 pups had histologic evidence of hypopituitarism, the remaining 2 pups had normal serum growth hormone concentration and adrenocorticotropin secretory capability, and normal adrenal function test and thyroid function study results. Furthermore, the initially stunted German Shepherd Dogs grew at a steady rate until at 1 year, body weight and shoulder height approximated normal measurements. Seemingly, delayed growth in these pups may represent one end of a clinical spectrum associated with hypopituitarism in German Shepherd Dogs.

Free access
in Journal of the American Veterinary Medical Association

Summary

Recombinant canine granulocyte colony-stimulating factor (rcG-CSF) was administered to clinically normal dogs, cyclic-hematopoietic dogs, and dogs undergoing autologous bone marrow transplantation, to determine whether rcG-CSF could be used to stimulate wbc production and function in normal and neutropenic dogs. To the normal dogs, rcG-CSF was administered by sc injection at rates of 1 μg/kg of body weight, q 12 h; 2 μg/kg, q 12 h; or 5 μg/kg, q 12 h. A significant dose-dependent increase in the wbc count resulted from the stimulation of bone marrow progenitor cells. The increased wbc count was characterized by mature neutrophilia and monocytosis. Neutrophil myeloperoxidase and phagocytic activity were normal in rcG-CSF-treated normal dogs, demonstrating the production of normal functional neutrophils in response to rcG-CSF treatment.

Recombinant canine G-CSF prevented neutropenia and associated clinical signs but did not completely eliminate the cycling of neutrophils in cyclic-hematopoietic dogs when it was administered at rates of 1 μg/kg, q 12 h, and 2.5 μg/kg, q 12 h. The time to bone marrow reconstitution was not decreased in dogs treated with rcG-CSF at a rate of 2.5 μ/kg, q 12 h, for 13 days following autologous bone marrow transplantation. On the basis of our findings, we suggest that treatment with rcG-CSF is an effective way to stimulate myelopoiesis in dogs, but that the dose of rcG-CSF required to stimulate wbc production will vary depending on the cause of neutropenia. Recombinant canine G-CSF should be useful in stimulating production and maintaining function of wbc for treatment of clinical diseases seen commonly in veterinary practice.

Free access
in Journal of the American Veterinary Medical Association

Summary

Adrenocortical adenoma, nodular hyperplasia, or carcinoma was diagnosed in 50 ferrets. Thirty-five (70%) ferrets were female and 15 (30%) were male. The mean age at which clinical signs were first noticed was 3.4 years (range, 1 to 7 years). Clinical signs included large vulva (n = 31; 89% of females), alopecia (n = 43; 86%), pruritus (n = 20; 40%), and increased consumption of water and increased urine output (n = 4; 8%). A mass was palpated at the cranial pole of the kidney during physical examination of 17 (34%) ferrets. Ultrasonography, performed on 39 of 50 ferrets, revealed a unilateral adrenal gland mass in 19 (49%). Four ferrets were anemic, and 2 ferrets were thrombocytopenic. Baseline plasma concentrations of cortisol and corticosterone were within or below the reference range in all 17 ferrets tested, whereas baseline plasma estradiol concentrations were high in 4 of the 11 ferrets (36%) tested. After adrenocorticotropic hormone (acth) administration, only 1 ferret had a slightly exaggerated response on the basis of plasma cortisol concentrations, and all 17 had normal responses on the basis of plasma corticosterone concentrations. There was little or no increase in plasma estradiol concentrations after acth administration. Of the 50 ferrets, 39 were treated by adrenalectomy. Unilateral adrenalectomy was performed in 34 ferrets in which 1 adrenal gland was large, whereas subtotal bilateral adrenalectomy was performed in 5 ferrets with bilateral adrenal disease. Five ferrets died in the immediate postoperative period, and follow-up information was available for the remaining 34, 1 to 34 months after surgery. A decrease in vulvar size was generally noticed by 2 days after surgery, and complete hair regrowth was noticed by 2 months.

Because clinical signs resolved after adrenalectomy, it was likely that the adrenocortical tumors and nodular hyperplasias of the adrenal gland were hyperfunctional. However, these ferrets did not have excessively high circulating concentrations of cortisol. At present, we recommended that diagnosis of adrenocortical disease in ferrets be made on the basis of characteristic clinical signs, results of abdominal ultrasonography, and finding large adrenal glands during surgery. Results of acth stimulation tests, with determination of plasma cortisol or corticosterone concentrations, were of no value in the diagnosis.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical status and renal and hematopoietic function after kidney donation and identify risks associated with kidney donation in dogs.

Design—Prospective study.

Animals—14 dogs that underwent unilateral nephrectomy for kidney donation.

Procedures—Records were reviewed retrospectively to collect data regarding prenephrectomy clinicopathologic variables. Dogs were reexamined prospectively at various times after nephrectomy, and pre- and postnephrectomy CBC, serum biochemical analyses, urinalysis, and urine protein-to-urine creatinine ratio were compared. Six dogs had postnephrectomy renal volume determined ultrasonographically, and 4 of those dogs also underwent scintigraphic determination of glomerular filtration rate and renal biopsy.

Results—All dogs were clinically normal at the time of reevaluation. There were no significant differences between prenephrectomy and postnephrectomy values for BUN concentration or urine specific gravity. Mean postnephrectomy serum creatinine concentration was significantly greater than prenephrectomy concentration. Mean serum phosphorus concentration was significantly decreased after nephrectomy, and mean Hct, corpuscular volume, and corpuscular hemoglobin concentration were significantly increased after nephrectomy. Postnephrectomy renal volume was greatest in dogs < 12 months old at the time of surgery. Mean postnephrectomy glomerular filtration rate was 2.82 ± 1.12 mL/kg/ min (1.28 ± 0.51 mL/lb/min). Renal biopsy specimens obtained during and after nephrectomy were histologically normal.

Conclusions and Clinical Relevance—Renal and hematopoietic variables were within reference ranges in dogs examined up to 2.5 years after unilateral nephrectomy. Compensatory renal hypertrophy was greatest in dogs < 1 year of age at donation. Donor age, along with histocompatability, may be an important factor in selecting dogs for kidney donation.

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in Journal of the American Veterinary Medical Association