Ichthyosis fetalis in Polled Hereford and Shorthorn calves
Inherited forms of ichthyosis, or generalized scaling of the skin, have been reported in many animal species, including cattle, and are characterized by an autosomal recessive mode of inheritance. We investigated 2 calves affected with ichthyosis fetalis, a Polled Hereford and a Shorthorn. Both cases had hard white plaques on the skin consistent with excessive keratinization. This was confirmed by histopathology, which showed severe diffuse epidermal and follicular orthokeratotic hyperkeratosis. The known mutation (H1935R) in gene ABCA12, responsible for ichthyosis fetalis in Chianina cattle, was shown to be absent in both affected calves and their obligate heterozygous parents. These molecular findings indicate that allelic heterogeneity exists for this condition in cattle.
Integumentary System
1. Explain why the skin is called the cutaneous membrane. 2. Name the layers of the skin, describe the structure (tissues) of each, and name a general function of each. 3. Discuss the four cell types present in the epidermis. 4. List the four/five layers of the epidermis and explain the process of keratinization. 5. Explain the protective role of keratin, and in turn, the epidermis. 6. Name the pigment responsible for skin and hair color, and explain how people of different races (i.e. and skin color) differ in regards to it, and the cell that produces it. 7. List some factors that promote the production of melanin (besides DNA). 8. Distinguish between the papillary layer and reticular layer of the dermis, and locate the appropriate sensory receptor in each of these layers. 9. Compare and contrast Meissner's and Pacinian Corpuscle's in terms of their structure, function, and location. 10. Describe the structure and function of the subcutaneous layer. 11. Explain what is meant by the term epidermal derivative, and list four examples. 12. Describe the general structure of a hair follicle and identify two other structures that are always associated with them. 13. Distinguish between merocrine (eccrine) and apocrine sweat glands in terms of structure, secretion content and odor, activation, and major body locations. 14. Name two modified apocrine glands of the skin.
Feline dermatology at Cornell University: 1407 cases (1988–2003)
Medical records of 1407 cats with dermatologic diagnoses made at Cornell University teaching hospital from 1988 to 2003 were tabulated. We expressed the diagnoses as counts, percentages of the cats with dermatologic disease (1407) and percentages of all cats seen at the university hospital (22,135) during the same period. A total of 1887 diagnoses were made in the 1407 cats. We compared the age, sex and breed group of our cases with all those 22,135 cats in (‘1-by-c’) χ2 tests in which the hospital population was considered a standard (rather than a ‘sample’). The 10 most common dermatoses, their counts, and the proportions of dermatologic diagnoses and of the total cat population that the cats with these dermatoses represented were: allergy (298; 15.8%; 1.35%), atopic dermatitis (194; 10.3%; 0.88%), bacterial folliculitis/furunculosis (189; 10.0%; 0.85%), otodectic mange (115; 6.1%; 0.52%), flea infestation (99; 5.2%; 0.45%), feline acne (74; 3.9%; 0.33%), flea-bite allergy (70; 3.7%; 0.32%), cutaneous adverse drug reaction (56; 3.0%; 0.25%), idiopathic eosinophilic-granuloma complex (55; 2.9%; 0.25%) and abscess (51; 2.7%; 0.23%). Allergies of all types, combined, accounted for 32.7% of all the feline dermatoses. Relative to the standard of the total hospital population, cats <2 years old and females (both intact and spayed) were significantly under-represented (all P≤0.001) in the dermatologic case series. In contrast, Himalayans (compared with domestic short- or longhair, Persian, Siamese and other breeds) and males (both intact and neutered) were significantly over-represented (all P ≤0.001).