Defects in collagen fibrillogenesis causing hyperextensible, fragile skin in dogs.
ABSTRACT Two unrelated mixed-breed dogs were donated for studies of their fragile, hyperextensible skin. Breeding of these dogs to bitches with normal skin showed that half of their male and female offspring also had fragile, hyperextensible skin, indicating that the defect was transmitted as an autosomal dominant trait in both dogs. Electron microscopy showed distinct abnormalities in the packing of collagen into fibrils and fibers in affected skin. These packing defects in dermal collagen were identical in related dogs, but were slightly different in unrelated animals. A clinical test, the skin extensibility index, was used to quantitate the extensibility of affected and unaffected skin. This index ranged from 8% to 15% in normal dogs and from 17% to 25% in newborn pups and adult dogs with collagen packing defects. The tensile strength of dorsolateral thoracic skin of affected pups was only 5% to 10% of that of matched specimens of paired littermates. The hyperextensibility and fragility of skin were the only clinical signs, but radiographic and microradiographic studies revealed subclinical involvement of bone.
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Article: Ehlers-Danlos syndrome in a dog.The Canadian veterinary journal. La revue veterinaire canadienne 05/1990; 31(5):389-90. · 0.77 Impact Factor
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ABSTRACT: To describe the clinical, histological, and immunohistochemical manifestations of canine necrotizing scleritis. A retrospective examination of the clinical records and samples of ocular tissues from five dogs with a histological diagnosis 'necrotizing scleritis' was completed. Archived, formalin-fixed, paraffin-embedded samples and two control globes were stained with hematoxylin and eosin, Gram, periodic acid-Schiff (PAS) and Masson trichrome stains, and they were immunohistochemically labeled for CD3, CD18, and CD20. Of the five cases reviewed, only two could be confirmed as idiopathic necrotizing scleritis. The other three cases were retrospectively diagnosed as unilateral focal, non-necrotizing scleritis, one as episcleritis and the third was scleritis secondary to a proptosed globe based on our retrospective clinical, histological, and immunohistochemical evaluations. In these two cases, idiopathic necrotizing scleritis manifested as a bilateral, progressive, inflammatory disease of the sclera and cornea that induces significant uveitis. Light microscopic examination confirmed collagen degeneration and granulomatous inflammation. There was no evidence for an infectious etiology based on Gram's and PAS stainings. Immunohistochemical labeling revealed a predominance of B cells in idiopathic, bilateral necrotizing scleritis. Tinctorial staining abnormalities with Masson's trichrome stain were present in scleral collagen of the two cases with idiopathic necrotizing scleritis as well as a case of secondary traumatic scleritis. Based on a limited number of cases, idiopathic canine necrotizing scleritis shares similar histopathological features with non-necrotizing scleritis and episcleritis; however, necrotizing scleritis is B-cell-dominated and bilateral, and significant collagen alterations manifest with Masson's trichrome stain.Veterinary Ophthalmology 09/2011; 15(2):102-9. · 0.96 Impact Factor
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ABSTRACT: The biomechanical properties of wounded and nonwounded skin were studied in three dogs and three cats affected with type I Ehlers-Danlos syndrome. Three nonaffected dogs and one nonaffected cat served as controls. Samples of wounded skin and adjacent normal skin were harvested at days 75, 138, 141, 144, 147, and 150. Samples were subjected to uniaxial tensile strength testing. Tensile strength, energy absorbed, and site of failure were recorded. In the dogs with Ehlers-Danlos syndrome, there was an increase in tensile strength in samples containing a scar over adjacent intact skin. In nonaffected dogs, affected cats and the nonaffected cat, the nonwounded skin samples had greater tensile strength. The energy absorbed by the skin samples during testing was highly correlated with tensile strength.Veterinary Surgery 01/1989; 18(2):97-102. · 1.24 Impact Factor