Colour dilution alopecia in seven Dachshunds. A clinical study and the hereditary, microscopical and ultrastructural aspect of the disease

Abstract Seven Dachshunds from five different families were studied for late-onset alopecia. All were born blue and tan in litters containing unaffected wild boar coated animals. Six of the seven dogs changed their colour during the first months of their life from blue and tan to ‘deadleaf’ or grey and tan. Histopathology, light microscopy of hairs and scanning electron microscopy of the hairs showed similarities with those previously described in blue Doberman Pinschers and confirmed the diagnosis of colour dilution alopecia (CDA). Transmission electron microscopy of cross-sectioned hairs showed vacuoles containing melanin granules of different size in medullary, subcortical and intracortical areas. Some opened at the hair surface and released melanin granules. Study of the pedigree proved autosomal recessive inheritance. Résumé— 7 teckels de 5 families ont fait l'objet de cette étude. Tous sont nés bleu et feu et proviennent de portées comprenant des chiots sains couleur sanglier. Six de ces chiens ont changé leur couleur durant les premiers mois de leur vie, passant ainsi du bleu et feu à‘feuilles mortes’ ou gris et feu. Histologiquement, l'examen microscopique des poils et l'examen ultrastructural à balayage montrent des lésions similaires à celles décrites chez les Dobermanns Pinschers bleus, et confirment le diagnostic d'Alopécie des Robes Diluées (ARD). La microscopie électronique à transmission des poils sectionnés montre des vacuoles contenant des grains de mélanine dans les régions médullaires, subcorticales, et intracorticales des poils. Quelques poils montrent la sortie des granules de mélanine à la surface du poil. L'étude des pédigrés prouve un mode de transmission autosomal récessif de cette maladie. [Beco, L., Fontaine, J., Gross, T.L., Charlier, G. Colour dilution alopecia in seven Dachshunds. A clinical study and the hereditary, microscopical and ultrastructural aspects of the disease (Alopécie des Robes Diluées chez 7 teckels: étude clinique et aspects héréditaires, microscopiques et ultrastructuraux). Veterinary Dermatology 1996; 7 : 91–97.] Resumen Se estudió la alopecia de aparición tardía en siete perros Dashshund de cinco familias diferentes. Todos los cachorros nacieron de color azul y canela en camadas que contenían animates con pelaje jabalí, sin afectación. Seis de los siete perros cambiaron su color durante los primeros meses de vida de azul y canela a ‘hoja seca’ o gris y canela. La histopatologia, la microscopía óptica de los pelos y la microscopía electrónica de barrido de los pelos mostraron similitudes con los previamente descritos en los Doberman Pinscher azules y confirmaron el diagnóstico de alopecia de color diluido (ACD). La microscopia electrónica de transmisión de cortes transversales del pelo mostraron vacuolas que contenían gránulos de melanina de tamaño variable en las zonas medular, subcortical e intracortical. Algunos se abrían a la superficie del pelo y liberaban gránulos de melanina. El estudio del pedigree reveló una forma de herenicia autosómica recesiva. [Beco, L., Fontaine, J., Gross, T.L., Charlier, G. Colour dilution alopecia in seven Dachshunds. A clinical study and the hereditary, microscopical and ultrastructural aspects of the disease (Alopecia de color diluido en siete Dachshunds. Estudio clinico y aspectos hereditarios, microscopicos y ultraestructurales de la enfermedad). Veterinary Dermatology 1996; 7 : 91–97.] Zusammenfassung— Sieben Dackel aus fünf verschiedenen Familien wurden wegen Alopezie mit spätem Beginn untersucht. Alle wurden als ‘blau und tan’ in Würfen geboren, die gesunde saufarbene aufwiesen. Sechs der sieben Hunde änderten ihre Farbe während der ersten Lebensmonate von ‘blau und tan’ nach ‘dürrlaub’ oder ‘grau und tan’. Histopathologisch zeigten Lichtmikroskopie der Haare und Elektronen-mikroskopabtastung der Haare Ähnlichkeiten mit denen früher beschriebener Veränderungen beim blauen Dobermann, und bestätigten die Diagnose Farbverdünnungsalopezie (CDA). Die Transmissionselek-tronenmikroscopie von quergeschnittenen Haaren zeigte Vakuolen, die Melaningranula verschiedener Größe in medullären, subkortikalen und intrakortikalen Zonen enthielten. Einige öffneten sich hin zur Haarober fläche und entließen die Melaningranula. Die Untersuchung der Abstammung zeigte eine autosomal rezessive Erblichkeit. [Beco, L., Fontaine, J., Gross, T. L., Charlier, G. Colour dilution alopecia in seven dachschunds. A clinical study and the hereditary microscopical and ultrastructural aspects of the disease (Farbverdünnungsalopezie bei sieben Dackeln. Eine klinische Studie über erbliche, mikroskopische und ultrastrukturelle Aspekte dieser Erkrankung). Veterinary Dermatology 1996; 7 : 91–97.]     

A double-blind,randomized, placebo-controlled study of pimobendan in dogs with dilated cardiomyopathy

A double-blind, randomized, placebo-controlled study was conducted to examine the effect on heart failure class and survival of pimobendan, an oral calcium-sensitizing inodilator, in dogs with dilated cardiomyopathy (DCM). Pimobendan (0.3-0.6 mg/kg body weight/d) or placebo was administered to English Cocker Spaniels (CSs; n = 10) and Doberman Pinschers (DPs: n = 10) that had DCM in addition to background therapy of furosemide, enalapril, and digoxin. Addition of pimobendan to standard triple therapy was associated with a significant improvement in heart failure class, regardless of breed (P < .02, Mann-Whitney rank sum test). Overall, 8 of 10 animals in the pimobendan-treated group, and 1 of 10 animals in the placebo group improved their heart failure status by at least I modified New York Heart Association functional class after initial stabilization (P = .005, Fisher's exact test). Pimobendan had no significant effect on survival in the CSs (P = 0.77, log-rank test), but DPs treated with pimobendan had significantly longer survival times compared with placebo (P < .02, log-rank test), with a median survival time of 329 days in the pimobendan group compared with 50 days in the placebo group, and a hazard ratio of 3.4 (95% confidence interval 1.4-39.8). Pimobendan resulted in significant improvement in heart failure class when added to standard therapy in this group of dogs with DCM, and may have contributed to improved survival in DPs.     

A prospective genetic evaluation of familial dilated cardiomyopathy in the Doberman pinscher

BACKGROUND: The Doberman Pinscher is one of the most common breeds of dogs to develop dilated cardiomyopathy (DCM), a primary heart muscle disorder characterized by myocardial dysfunction, cardiac arrhythmias, and congestive heart failure. In the Doberman Pinscher, the disease is typically adult onset, and a familial etiology has been suggested. HYPOTHESIS: DCM in the Doberman Pinscher, is a familial disease linked to a specific genetic marker. ANIMALS: The study comprised an extended family of Doberman Pinschers with a history of DCM. METHODS: Participating dogs were prospectively evaluated over an 8-year period. Phenotype of participating dogs was determined by annual echocardiography and ambulatory electrocardiography, and the pedigree was evaluated to determine a specific mode of inheritance. Three hundred seventy-two microsatellite markers were selected and genotyped to cover the 38 autosomal chromosomes. Phenotyping, genotyping, and pedigree information was entered into a database, and parametric, 2-point analysis was performed. Markers were considered to be linked to the development of DCM if the logarithm of odds LOD score was >/= 3.0. RESULTS: An autosomal dominant mode of inheritance was defined by the appearance of the disease in multiple generations, equal gender representation (P = .973) and male-to-male transmission. A maximum LOD score of 1.31 was obtained for I marker on chromosome 20, a score not high enough to be associated with DCM. CONCLUSION: DCM in the Doberman Pinscher is a familial disease inherited as an autosomal dominant trait. The causative gene(s) responsible for this condition remain unresolved. Association studies by means of array technology may provide new insights into gene identification.     

Chronic hepatitis in Doberman pinschers. A review

Summary

Chronic hepatitis in Doberman pinschers is predominantly seen in female dogs, usually between 4 and 7 years of age and was first recognized in the early eighties. The histopathological characteristics of Doberman hepatitis are those of micronodular cirrhosis with histological features of fibrosis, piece meal necrosis and progressive lymphocyte and plasma cell infiltration of the portal triads. Currently there are two hypotheses on the pathogenesis although neither of them has been elucidated. The first hypothesis is that of a copper toxicosis. The second is that of autoimmunity. Similarities and differences with other breeds and studies on both hypotheses are reviewed, as well as results of recent research of our group. Based on recent findings chronic hepatitis in Doberman pinschers is most likely to be a form of copper toxicosis. Although there are several indications that suggest autoimmunity as well, this still remains unclear.     

MENSURATION OF CERVICAL VERTEBRAL RATIOS IN DOBERMAN PINSCHERS AND GREAT DANES

Canine cervical vertebral instability is a complex syndrome involving cervical spinal cord compressive lesions. Doberman pinschers and Great Danes are the most commonly affected breeds. Measurements of vertebral canal diameter (VCD), vertebral body height (H), and vertebral body length (L) were made from C3-C7 in 24 Doberman pinschers and 8 Great Danes by using digital and analog techniques. Significant differences between affected and unaffected sites were noted for Doberman pinschers at C6 (P = 0.039) and C7 (P = 0.027) using analog measurements of VCD/H, and Great Danes at C6 using analog (P = 0.041) and digital (P = 0.004) measurements of VCD/L. Cervical vertebral ratios have potential as a breed-specific screening tool for cervical vertebral instability and warrant longitudinal studies.     

Multiple skin tumours in a Doberman Pinscher with colour dilution alopecia

Abstract An 11-year-old Doberman Pinscher with clinical and histological skin features consistent with colour dilution alopecia had a long history of skin disease. The animal had hundreds of papules affecting the ‘blue’ haired áreas of the hair coat. The predominant skin lésions included keratinizing infundibular cysts, keratin horns, perifollicular dermatitis, and sebaceous hyperplasia; these lésions were often accompanied by fürunculosis and suppurative panniculitis. Over a 9-month period, 32 lésions were examined histologically, which included two lipomas, one infiltrative lipoma, one squamous papilloma, two mast cell tumours, four cavernous haemangiomas, one haemangiosarcoma, and three melanomas. It is unknown at present whether the colour dilution phenotype confers increased risk for tumours of the skin and or subcutaneous tissues. Résumé— Un doberman de 11 ans avec des manifestations cutanées cliniques et histologiques compatibles avec le díagnostic d'alopécie des couleurs diluées avait une longue histoire de problèmes cutanés. L'animal présentait des centaines de papules affectant les zones de couleur bleue. Les lésions cutanées prédominantes consistaient en kystes infundibulaires kératinisants, cornes cutanées, dermatite périfolliculaire et hyperplasie sébacée; ces lésions s'accompagnaient souvent de füronculose et de panniculite suppurative. Sur une période de 9 mois, 32 lésions ont fait l'objet d'un examen histologique, dont deux lipomes, un lipome infiltrant, un papillome, deux mastocytomes, quatre hémangiomes caverneux, un hémangiosarcome, et trois mélanomes. On ne sait actuellement pas si le phénotype couleur diluée constitue un facteur de risque accru pour les tumeurs de la peau et des tissus sous cutanés. [Madewell, B. R., Ihrke, P. J., Griffey, S. M. Multiple skin tumours in a Doberman Pinscher with colour dilution alopecia. (Tumeurs cutanées multiples chez un doberman présentant une alopécie des couleurs diluées.) Veterinary Dermatology 1997; 8 : 59–62.] Resumen Un doberman pinscher de 11 años con caracteristicas clinicas e histológicas compatibles con alopecia de color diluido tenia una larga historia de enfermedad cutanea. El animal presentaba centenares de pápulas afectando las áreas de pelo “azul”. Las lesiones prédominantes incluian quistes infundibulares queratinizados, cuernos de queratina, dermatitis perifolicular e hiperplasia sebácea; estas lesiones se acompañaban de fürunculosis y paniculitis supurativa. Durante un periodo de 9 meses, 32 lesiones fueron examinadas histológicamente, incluyendo 2 lipomas, un lipoma infiltrativo, un papiloma escamoso, dos mastocitomas, cuatro hemangiomas cavernosos, un hemangiosarcoma y tres melanomas. Se desconoce aún si el fenotipo de color diluido aumenta el riesgo para la aparición de tumores en tejidos cutáneos y subcutáneos. [Madewell, B. R., Ihrke, P. J., Griffey, S. M. Multiple skin tumours in a Doberman Pinscher with colour dilution alopecia. (Multiples tumores cutáneos en un Doberman Pinscher con alopecia de color diluido.) Veterinary Dermatology 1997; 8 : 59–62.] Zusammenfassung— Ein elfjähriger Dobermann mit klinischen und histologischen Befunden, die bei Farbmutantenalopezie auftreten, wies eine lange Vorgeschichte mit Hautkrankheiten auf. Das Tier zeigte Hunderte von Papeln, die die “blau” behaarten Bezirke des Felles betrafen. Die vorherrschenden Hautveränderungen bestanden in keratinisierenden infundibulären Zysten, Keratinhörnern, perifollikulärer Dermatitis und Talgdrüsenhyperplasie; diese Veränderungen wurden oft von Furunkulose und eitriger Pannikulitis begleitet. Über eine Zeitspanne von 9 Monaten wurden 32 Veränderungen histologisch untersucht, wovon zwei in Lipomen bestanden, eine in einem infiltrativen Lipom, eine in einem squamösen Papillom, zwei in Mastzelltumoren, vier in kavernösen Hämangiomen, eine in einem Hämangiosarkom und drei in Melanomen. Es ist zur Zeit nicht bekannt, ob der Phänotyp mit der Farbverdünnung mit einem erhöhten Risiko für Tumoren der Haut und/oder des subkutanen Gewebes einhergeht. [Madewell, B. R., Ihrke, P. J., Griffey, S. M. Multiple skin tumours in a Doberman Pinscher with colour dilution alopecia. (Multiple Hauttumoren bei einem Dobermann mit Farbmutantenalopezie.) Veterinary Dermatology 1997; 8 : 59–62.]