06.09.2016 

Swiss Canine Cancer Registry 1955-2008: Occurrence of the Most Common Tumour Diagnoses and Influence of Age, Breed, Body Size, Sex and Neutering Status on Tumour Development.

Grüntzig K, Graf R, Boo G, Guscetti F, Hässig M, Axhausen KW, Fabrikant S, Welle M, Meier D, Folkers G, Pospischil A.

J Comp Pathol. 2016, Jul 9. pii: S0021-9975(16)30050-0. doi: 10.1016/j.jcpa.2016.05.011.

This study is based on the Swiss Canine Cancer Registry, comprising 121,963 diagnostic records of dogs compiled between 1955 and 2008, in which 63,214 (51.83%) animals were diagnosed with tumour lesions through microscopical investigation.

Adenoma/adenocarcinoma (n = 12,293, 18.09%) was the most frequent tumour diagnosis. Other common tumour diagnoses were: mast cell tumour (n = 4,415, 6.50%), lymphoma (n = 2,955, 4.35%), melanocytic tumours (n = 2,466, 3.63%), fibroma/ fibrosarcoma (n = 2,309, 3.40%), haemangioma/ haemangiosarcoma (n = 1,904, 2.80%), squamous cell carcinoma (n = 1,324, 1.95%) and osteoma/ osteosarcoma (n = 842, 1.24%). The relative occurrence over time and the most common body locations of those tumour diagnoses are presented. Analyses of the influence of age, breed, body size, sex and neutering status on tumour development were carried out using multiple logistic regression. In certain breeds/breed categories the odds ratios (ORs) for particular tumours were outstandingly high: the boxer had higher ORs for mast cell tumour and haemangioma/haemangiosarcoma, as did the shepherd group for haemangioma/haemangiosarcoma, the schnauzer for squamous cell carcinoma and the rottweiler for osteoma/osteosarcoma. In small dogs, the risk of developing mammary tumours was three times higher than in large dogs. However, small dogs were less likely to be affected by many other tumour types (e.g. tumours of the skeletal system). Examination of the influence of sex and neutering status on tumour prevalence showed that the results depend on the examination method. In all sampling groups the risk for female dogs of developing adenoma/adenocarcinoma was higher than for male dogs. Females had a lower risk of developing haemangioma/haemangiosarcoma and squamous cell carcinoma than males. Neutered animals were at higher risk of developing specific tumours outside the genital organs than intact animals. The sample size allows detailed insight into the influences of age, breed, body size, sex and neutering status on canine tumour development. In many cases, the analysis confirms the findings of other authors. In some cases, the results are unique or contradict other studies, implying that further investigations are necessary.

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Bowenoid in situ carcinomas in two Devon Rex cats: evidence of unusually aggressive neoplasm behaviour in this breed and detection of papillomaviral gene expression in primary and metastatic lesions.

Munday JS1, Benfell MW2, French A3, Orbell GM3, Thomson N1.

Vet Dermatol. 2016 Jun;27(3):215-e55. doi: 10.1111/vde.12319.

Bowenoid in situ carcinomas (BISCs) are rare feline tumours that are thought to be caused by papillomavirus infection. Although they usually develop in old cats and are slowly progressive, multiple aggressive BISCs have been reported previously in a comparatively young Devon Rex cat. A 5-year-old (Case 1) and an 8-year-old (Case 2) Devon Rex cat developed numerous BISCs. Rapid progression resulted in euthanasia of both cats after 8 months. A postmortem examination was possible only for Case 2 and revealed pulmonary metastases. Consensus PCR amplified only Felis catus papillomavirus type 2 (FcaPV-2) DNA from lesions from both cats. High FcaPV-2 copy number and FcaPV-2 E6/E7 gene expression were detected in a BISC from Case 1. High FcaPV-2 copy number and FcaPV-2 gene expression were detected in a BISC, a cutaneous squamous cell carcinoma (SCC) and the pulmonary metastases from Case 2, but not in two other cutaneous SCCs.

The results provide additional evidence that BISCs develop at a younger age in Devon Rex cats and that BISCs in Devon Rex cats have a more aggressive behaviour than BISCs in other cat breeds. These unusual features should be considered when evaluating and treating skin disease in Devon Rex cats. The detection of FcaPV-2 gene expression in the lung neoplasms suggests a potential role of FcaPV-2 in the development of metastatic disease. However, the absence of FcaPV-2 gene expression in two cutaneous SCCs suggests that other factors could have also promoted cancer development.

Two Canine Papillomaviruses Associated With Metastatic Squamous Cell Carcinoma in Two Related Basenji Dogs.

Luff J, Rowland P, Mader M, Orr C, Yuan H.

Vet Pathol. 2016 Mar 4. pii: 0300985816630795. [Epub ahead of print]

Papillomaviruses (PV) are associated with benign mucosal and cutaneous epithelial proliferations. In dogs, PV-associated pigmented plaques and papillomas can undergo malignant transformation, but this is rare, and most cases of canine squamous cell carcinoma do not arise from PV-induced precursor lesions. We describe herein the progression of pigmented plaques to invasive and metastatic squamous cell carcinoma associated with 2 canine papillomaviruses (CPV) in 2 related Basenji dogs. Immunohistochemistry for PV antigen revealed strong nuclear immunoreactivity within keratinocytes from pigmented plaques from both dogs, consistent with a productive viral infection. Polymerase chain reaction (PCR) using degenerate primers for the L1 gene revealed PV DNA sequences from 2 different CPVs. In situ hybridization for CPV revealed strong hybridization signals within the pigmented plaques and neoplastic squamous epithelial cells from both dogs. We report here progression of PV-associated pigmented plaques to metastatic squamous cell carcinoma within 2 Basenji dogs associated with 2 different CPVs.

Molecular and immunohistochemical studies do not support a role for papillomaviruses in canine oral squamous cell carcinoma development.

Vet J. 2015 May;204(2):223-5. doi: 10.1016/j.tvjl.2015.03.002. Epub 2015 Mar 5.

Oral squamous cell carcinomas (OSCCs) are common neoplasms of dogs and are of unknown cause. Whereas papillomaviruses (PVs) are an established cause of human OSCCs, few studies have investigated canine OSCCs for a PV aetiology. In humans, a PV aetiology can be determined by detecting PV DNA and PV-induced increased p16(CDKN2A) protein (p16) within the OSCC. In this study, PCR, using four different primer sets and p16 immunohistochemistry, was used to evaluate 28 canine OSCCs for a possible PV aetiology. None of the primers amplified PV DNA from any of the OSCCs although four neoplasms contained intense p16 immunostaining. Intense p16 immunostaining would indicate a PV aetiology in a human OSCC but the absence of PV DNA suggests that the increase in p16 was not due to PV infection. Overall the results indicated that PVs are not a significant cause of canine OSCCs.

Association of breed and histopathological grade in canine mast cell tumours.

Mochizuki H, Motsinger-Reif A, Bettini C, Moroff S, Breen M.

Vet Comp Oncol. 2016 May 19. doi: 10.1111/vco.12225. [Epub ahead of print]

The aim of this study was to evaluate the relationship between breed and the histopathological grade of canine mast cell tumours (MCTs). A retrospective survey of pathology data of 9375 histopathologically confirmed diagnoses of cutaneous MCTs in the US was evaluated in the context of breed prevalence in over two million registered purebred dogs. Association of histopathological grade with breed, age, sex and spay/neuter status was assessed. The data indicate that the proportion of high-grade tumours increases with advancing age, and that male and intact dogs have increased odds of developing high-grade tumours. A significant difference in the proportion of high-grade tumours between breeds was detected. The Pug was at significantly increased risk of developing low/intermediate-grade tumours, but not high-grade tumours, resulting in preponderance of less aggressive MCTs in this breed. The results of this study suggest a genetic association for the development of high-grade MCTs.

Cytologic Criteria for Mast Cell Tumor Grading in Dogs With Evaluation of Clinical Outcome.

Camus MS, Priest HL, Koehler JW, Driskell EA, Rakich PM, Ilha MR, Krimer PM.

Vet Pathol. 2016 Mar 31. pii: 0300985816638721. [Epub ahead of print]

A 2-tiered histologic grading scheme for canine cutaneous mast cell tumors (MCTs) is based on morphologic characteristics of neoplastic cells, including karyomegaly, multinucleation, nuclear pleomorphism, and mitotic figures. Aspirates from MCTs may provide the same information more quickly, inexpensively, and less invasively. This study used these criteria to develop a cytologic grading scheme for canine MCTs to predict outcome. Three anatomic pathologists graded histologic samples from 152 canine MCTs. Three clinical pathologists evaluated aspirates from these masses using similar criteria. A cytologic grading scheme was created based on correlation with histologic grade and evaluated with a kappa statistic. Survival was evaluated with Kaplan-Meier survival curves. Cox proportional hazards regression was used to estimate hazard ratios for tumor grades and individual grading components. Simple logistic regression tested for relationships between risk factors and mortality. The cytologic grading scheme that best correlated with histology (kappa = 0.725 ± 0.085) classified a tumor as high grade if it was poorly granulated or had at least 2 of 4 findings: mitotic figures, binucleated or multinucleated cells, nuclear pleomorphism, or >50% anisokaryosis. The cytologic grading scheme had 88% sensitivity and 94% specificity relative to histologic grading. Dogs with histologic and cytologic high grade MCTs were 39 times and 25 times more likely to die within the 2-year follow-up period, respectively, than dogs with low grade MCTs. High tumor grade was associated with increased probability of additional tumors or tumor regrowth. This study concluded that cytologic grade is a useful predictor for treatment planning and prognostication.

Prevalence and risk factors for mast cell tumours in dogs in England.

Shoop SJ, Marlow S, Church DB, English K, McGreevy PD5, Stell AJ, Thomson PC, O'Neill DG, Brodbelt DC.

Canine Genet Epidemiol. 2015 Jan 26;2:1. doi: 10.1186/2052-6687-2-1. eCollection 2015.

Mast cell tumour (MCT) appears to be a frequent tumour type in dogs, though there is little published in relation to its frequency in dogs in the UK. The current study aimed to investigate prevalence and risk factors for MCTs in dogs attending English primary-care veterinary practices. Electronic patient records from practices participating in the VetCompass animal surveillance project between July 2007 and June 2013 were searched for MCT diagnosis. Various search terms and standard diagnostic terms (VeNom codes) identified records containing MCT diagnoses, which were evaluated against clinical criteria for inclusion to the study. MCT prevalence for the entire dataset and specific breed types were calculated. Descriptive statistics characterised MCT cases and multivariable logistic regression methods evaluated risk factors for association with MCT (P < 0.05).

Within a population of 168,636 dogs, 453 had MCT, yielding a prevalence of 0.27% (95% confidence interval (CI) 0.24% - 0.29%). The highest breed type specific prevalences were for the Boxer at 1.95% (95% CI 1.40% - 2.51%), Golden Retriever at 1.39% (0.98% - 1.81%) and Weimaraner at 0.85% (95% CI 0.17% to 1.53%). Age, insurance status, neuter status, weight and breed type were associated with MCT diagnosis. Of dogs of specific breed type, the Boxer, Pug and Staffordshire Bull Terrier showed greater odds of MCT diagnosis compared with crossbred dogs. Conversely, the German Shepherd Dog, Border Collie, West Highland White Terrier, Springer Spaniel and Cocker Spaniel had reduced odds of MCT diagnosis compared with crossbred dogs. No association was found between MCT diagnosis and sex. This study highlights a clinically significant prevalence of MCT and identifies specific breed types with predisposition to MCT, potentially aiding veterinarian awareness and facilitating diagnosis.

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Cryptococcosis as an emerging systemic mycosis in dogs.

Vorathavorn VI, Sykes JE, Feldman DG.

J Vet Emerg Crit Care (San Antonio). 2013 Sep-Oct;23(5):489-97. doi: 10.1111/vec.12087. Epub 2013 Aug 23.

Cryptococcosis is a multisystemic disease of dogs, with a predilection for the CNS, caused by encapsulated yeast species of the genus Cryptococcus. The 2 main pathogenic species are Cryptococcus neoformans and Cryptococcus gattii (previously known as C. neoformans var. gattii). Cryptococcosis is an emerging disease in North America, with C. gattii gaining prominence as a cause of serious veterinary and human disease. Definitive diagnosis is made by serologic (antigen) testing, culture, and identification of the organism using light microscopy. False negatives and false positives, while uncommon, can occur in dogs using commercially available antigen tests. Cytological examination demonstrates the organism in a majority of cases, although culture is more sensitive. Specific media are required to differentiate between C. neoformans and C. gattii. The most commonly used antifungal drugs to treat canine cryptococcosis are azole antifungals and amphotericin B. Some strains of Cryptococcus are resistant to antifungal drugs, especially fluconazole. Cautious use of glucocorticoids in critically affected dogs with CNS presentations can improve outcome. Prognosis is variable and depends on the severity of disease, underlying host immunocompetence, and financial constraints of the owner. Altered mental status in dogs with CNS cryptococcosis is a negative prognostic indicator.

Comparison of 2 Doses for ACTH Stimulation Testing in Dogs Suspected of or Treated for Hyperadrenocorticism.

Aldridge C, Behrend EN, Kemppainen RJ, Lee-Fowler TM, Martin LG, Ward CR, Bruyette D, Pannu J, Gaillard P, Lee HP.

J Vet Intern Med. 2016 Jul 18. doi: 10.1111/jvim.14528. [Epub ahead of print]

Lowering the cosyntropin dose needed for ACTH stimulation would make the test more economical. To compare the cortisol response to 1 and 5 μg/kg cosyntropin IV in dogs being screened for hyperadrenocorticism (HAC) and in dogs receiving trilostane or mitotane for pituitary-dependent HAC. Healthy dogs (n = 10); client-owned dogs suspected of having HAC (n = 39) or being treated for pituitary-dependent HAC with mitotane (n = 12) or trilostane (n = 15) were included. In this prospective study, healthy dogs had consecutive ACTH stimulation tests to ensure 2 tests could be performed in sequence. For the first test, cosyntropin (1 μg/kg IV) was administered; the second test was initiated 4 hours after the start of the first (5 μg/kg cosyntropin IV). Dogs suspected of having HAC or being treated with mitotane were tested as the healthy dogs. Dogs receiving trilostane treatment were tested on consecutive days at the same time post pill using the low dose on day 1. In dogs being treated with mitotane or trilostane, the 2 doses were pharmacodynamically equivalent (90% confidence interval, 85.1-108.2%; P = 0.014). However, in dogs suspected of having HAC, the doses were not pharmacodynamically equivalent (90% confidence interval, 73.2-92.8%; P = 0.37); furthermore, in 23% of the dogs, clinical interpretation of test results was different between the doses. For dogs suspected of having HAC, 5 μg/kg cosyntropin IV is still recommended for ACTH stimulation testing. For dogs receiving mitotane or trilostane treatment, a dose of 1 μg/kg cosyntropin IV can be used.

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Epidemiology of hyperadrenocorticism among 210,824 dogs attending primary-care veterinary practices in the UK from 2009 to 2014.

O'Neill DG, Scudder C, Faire JM, Church DB, McGreevy PD, Thomson PC, Brodbelt DC.

J Small Anim Pract. 2016 Jul;57(7):365-73. doi: 10.1111/jsap.12523. Epub 2016 Jun 9.

To estimate prevalence and risk factors for diagnosis with hyperadrenocorticism in dogs attending primary-care veterinary practices in the UK from 2009 to 2014. Cases were identified by searching the de-identified electronic patient records from UK primary-care veterinary practices participating in the VetCompass Programme. The estimated prevalence for hyperadrenocorticism diagnosis in dogs was 0·28% (95% confidence interval: 0·25 to 0·31). Multivariable logistic regression analysis revealed four associated risk factors: breed, breed-relative bodyweight, age and insurance status. The bichon frise had 6·5 times the odds (95% CI: 3·5 to 12·1, P<0·001) of hyperadrenocorticism compared with crossbreds. Dogs weighing more than or equal to their breed mean had 1·7 times the odds (95% CI: 1·3 to 2·3, P<0·001) of hyperadrenocorticism compared with dogs weighing less than the breed mean. Dogs aged 12·0 years and above showed 5·7 times the odds (95% CI: 3·7 to 8·7, P<0·001) of hyperadrenocorticism compared with dogs aged 6·0 to 8·9 years. Insured dogs had 4·0 times the odds (95% CI: 2·8 to 5·6, P<0·001) of hyperadrenocorticism compared with non-insured dogs. This is the first epidemiological report of a non-referral hospital population of dogs diagnosed with hyperadrenocorticism in the UK and describes important breed, age and bodyweight associations with this disorder which may improve diagnosis and enhance understanding of the underlying pathophysiology.

Was war Ihrer Meinung nach die Ursache für das gehäufte Vorkommen von Hyperadrenokortizismus bei versicherten Hunden?

Comparison of adrenocorticotropic hormone stimulation test results started 2 versus 4 hours after trilostane administration in dogs with naturally occurring hyperadrenocorticism.

J Vet Intern Med. 2014 Jul-Aug;28(4):1239-43. doi: 10.1111/jvim.12357. Epub 2014 May 26.

Bonadio CM, Feldman EC, Cohen TA, Kass PH.

Trilostane medical treatment of naturally occurring hyperadrenocorticism (NOH) in dogs is common, as is use of the adrenocorticotropic hormone (ACTH) stimulation test (ACTHst) in monitoring response to treatment. There is uncertainty regarding when the ACTHst should be started relative to time of trilostane administration. The aim of this study was to compare ACTHst results in dogs being treated for NOH with trilostane when the test is begun 2 versus 4 hours after trilostane administration. Twenty-one privately owned dogs with NOH, each treated with trilostane for at least 30 days were included. Each dog had 2 ACTHst completed, 1 started 2 hours and the other 4 hours after trilostane administration. The second test was started no sooner than 46 hours and no later than 74 hours after the first. For all 21 dogs, the mean post-ACTH serum cortisol concentration from tests started 2 hours after trilostane administration (5.4 ± 3.7 μg/dL) was significantly lower (P = .03) as compared with results from the tests started 4 hours after administration (6.5 ± 4.5 μg/dL). Results of ACTHst started at different times yield significantly different results. Dogs with NOH, treated with trilostane, and monitored with ACTHst results should have all of their subsequent ACTHst tests begun at or about the same time after trilostane administration.

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The effect of imepitoin, a recently developed antiepileptic drug, on thyroid parameters and fat metabolism in healthy Beagle dogs.

Vet J. 2016 Jul;213:48-52. doi: 10.1016/j.tvjl.2016.03.008. Epub 2016 Mar 14.

Bossens K, Daminet S, Duchateau L, Rick M, Van Ham L, Bhatti S.

Since early 2013, imepitoin has been used in most European countries for the management of recurrent single generalised epileptic seizures in dogs with idiopathic epilepsy. It has been reported that imepitoin is as effective as phenobarbital (PB) in controlling seizures in dogs with newly diagnosed idiopathic epilepsy and it has a clinically superior safety profile. As the use of imepitoin gains popularity, its effect on serum thyroid parameters warrants further investigation since long-term PB administration influences thyroid parameters in dogs, which could lead to misinterpretation of laboratory results and incorrect diagnosis of thyroidal illness. A prospective study was conducted to compare the effect of orally administered PB and imepitoin on serum concentrations of total thyroxine (TT4), triiodothyronine, free thyroxine, thyroglobulin autoantibodies, thyroid-stimulating hormone, cholesterol and triglycerides in healthy Beagle dogs. These parameters were determined prior to and at 6, 12 and 18 weeks after antiepileptic drug administration. The starting dose of PB (5 mg/kg PO twice daily; range, 4.4-6.0 mg/kg) was monitored and adjusted to obtain optimal therapeutic serum concentrations (30-35 g/mL). Imepitoin was administered at 30 mg/kg PO twice daily (range, 29.2-35.7 mg/kg). Imepitoin administration did not affect any of the thyroid parameters over an 18-week period. In contrast, serum TT4 concentrations decreased significantly over time in dogs receiving PB (P <0.05). Serum cholesterol concentrations increased significantly over time in dogs in the imepitoin group, but not to the same extent as commonly seen in dogs with primary hypothyroidism.

Central Hypothyroidism in Miniature Schnauzers.

J Vet Intern Med. 2016 Jan-Feb;30(1):85-91. doi: 10.1111/jvim.13818. Epub 2015 Dec 23.

Voorbij AM, Leegwater PA, Buijtels JJ, Daminet S, Kooistra HS.

Primary hypothyroidism is a common endocrinopathy in dogs. In contrast, central hypothyroidism is rare in this species. The objective of this article is to describe the occurrence and clinical presentation of central hypothyroidism in Miniature Schnauzers. Additionally, the possible role of the thyroid-stimulating hormone (TSH)-releasing hormone receptor (TRHR) gene and the TSHβ (TSHB) gene was investigated. Miniature Schnauzers with proven central hypothyroidism, based on scintigraphy, and the results of a 3-day-TSH-stimulation test, or a TSH-releasing hormone (TRH)-stimulation test or both, presented to the Department of Clinical Sciences of Companion Animals at Utrecht University or the Department of Medicine and Clinical Biology of Small Animals at Ghent University from 2008 to 2012 were included. Pituitary function tests, thyroid scintigraphy, and computed tomography (CT) of the pituitary area were performed. Gene fragments of affected dogs and controls were amplified by polymerase chain reaction (PCR). Subsequently, the deoxyribonucleic acid (DNA) sequences of the products were analyzed. Central hypothyroidism was diagnosed in 7 Miniature Schnauzers. Three dogs had disproportionate dwarfism and at least one of them had a combined deficiency of TSH and prolactin. No disease-causing mutations were found in the TSHB gene and the exons of the TRHR gene of these Schnauzers. Central hypothyroidism could be underdiagnosed in Miniature Schnauzers with hypothyroidism, especially in those of normal stature. The fact that this rare disorder occurred in 7 dogs from the same breed suggests that central hypothyroidism could have a genetic background in Miniature Schnauzers.

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A Multi-Breed Genome-Wide Association Analysis for Canine Hypothyroidism Identifies a Shared Major Risk Locus on CFA12.

PLoS One. 2015 Aug 11;10(8):e0134720. doi: 10.1371/journal.pone.0134720. eCollection 2015.

Bianchi M, Dahlgren S, Massey J, Dietschi E, Kierczak M, Lund-Ziener M, Sundberg K, Thoresen SI, Kämpe O, Andersson G, Ollier WE, Hedhammar Å, Leeb T, Lindblad-Toh K, Kennedy LJ, Lingaas F, Rosengren Pielberg G.

Hypothyroidism is a complex clinical condition found in both humans and dogs, thought to be caused by a combination of genetic and environmental factors. In this study we present a multi-breed analysis of predisposing genetic risk factors for hypothyroidism in dogs using three high-risk breeds--the Gordon Setter, Hovawart and the Rhodesian Ridgeback. Using a genome-wide association approach and meta-analysis, we identified a major hypothyroidism risk locus shared by these breeds on chromosome 12 (p = 2.1x10(-11)). Further characterisation of the candidate region revealed a shared ~167 kb risk haplotype (4,915,018-5,081,823 bp), tagged by two SNPs in almost complete linkage disequilibrium. This breed-shared risk haplotype includes three genes (LHFPL5, SRPK1 and SLC26A8) and does not extend to the dog leukocyte antigen (DLA) class II gene cluster located in the vicinity. These three genes have not been identified as candidate genes for hypothyroid disease previously, but have functions that could potentially contribute to the development of the disease. Our results implicate the potential involvement of novel genes and pathways for the development of canine hypothyroidism, raising new possibilities for screening, breeding programmes and treatments in dogs. This study may also contribute to our understanding of the genetic etiology of human hypothyroid disease, which is one of the most common endocrine disorders in humans.

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Free thyroxine concentrations by equilibrium dialysis and chemiluminescent immunoassays in 13 hypothyroid dogs positive for thyroglobulin antibody.

J Vet Intern Med. 2015 May-Jun;29(3):877-81. doi: 10.1111/jvim.12573. Epub 2015 Apr 9.

Randolph JF, Lamb SV, Cheraskin JL, Schanbacher BJ, Salerno VJ, Mack KM, Scarlett JM, Place NJ.

To determine if concentrations of free thyroxine (FT4) measured by semi-automated chemiluminescent immunoassay (CLIA) correspond to FT4 determined by equilibrium dialysis (ED) in hypothyroid dogs positive for thyroglobulin antibody (TGA). Thirteen TGA-positive dogs classified as hypothyroid based on subnormal FT4 concentrations by ED. Qualitative assessment of canine TGA was performed using an enzyme-linked immunosorbent assay. Serum total thyroxine and total triiodothyronine concentrations were measured by radioimmunoassay. Serum FT4 concentration was determined by ED, and also by semi-automated CLIA for human FT4 (FT4h) and veterinary FT4 (FT4v). Canine thyroid stimulating hormone concentration was measured by semi-automated CLIA. Each dog's comprehensive thyroid profile supported a diagnosis of hypothyroidism. For detection of hypothyroidism, sensitivities of CLIA for FT4h and FT4v were 62% (95% CI, 32-85%) and 75% (95% CI, 36-96%), respectively, compared to FT4 by ED. Five of 13 (38%) dogs had FT4h and 2 of 8 (25%) dogs had FT4v concentrations by CLIA that were increased or within the reference range. Percentage of false-negative test results for FT4 by CLIA compared to ED was significantly (P < .0001 for FT4h and P < .001for FT4v) higher than the hypothesized false-negative rate of 0%. Caution should be exercised in screening dogs for hypothyroidism using FT4 measured by CLIA alone. Some (25-38%) TGA-positive hypothyroid dogs had FT4 concentrations determined by CLIA that did not support a diagnosis of hypothyroidism.

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 -Vorstand