Histopathology of the Diseases of the Skin

Epithelial Tumours of the Skin of Sheep

“…Muzzle, vulva and eye lesions: These were all squamous cell epitheliomata and all were markedly infected. Connective tissue degeneration.-A number of sections showed an alteration of the dermal connective tissue analogous to the collagen degeneration observed in the skin of man in those individuals who are prone to develop cancers in which sunlight is presumed to be the cause (Unna, 1896;Gillman et al, 1955;Mackie and McGovern, 1958). In sheep material stained with haematoxylin and eosin loss of structure of the collagen and associated basophilia was noted.…”

Studying the genetic predisposing factors in the pathogenesis of acne vulgaris

“…Beginning around puberty, a hormonal imbalance often leads to increased sebum secretion, especially in the facial skin areas [2,40], which initiates the extensive multiplication of P acnes in the follicles [41,42]. The pathogen recognition receptors TLR2 and TLR4 are important in the recognition of P acnes in epidermal keratinocytes, and through the initiation of gene expression changes, they regulate downstream innate immune events [43,44].…”

Angioid streaks and elastorrhexis.

“…This was originally thought to be an age change provoked by weathering (Unna, 1896;Hass, 1939); the old name of senile elastosis is misleading and should be discarded in favour of solar or actinic elastosis,* since * Actinic elastosis was preferred by the committee on nomenclature of the American Academy of Dermatology (cited by . the changes occur only in areas of skin exposed to the sun and are not related to age (Lund and Sommerville, 1957;.…”