Analysis Tools
integument
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• at P10, the area occupied by the sebaceous glands is 20% larger than that of wild-type controls
• sebaceous glands appear enlarged at P86 and at 1 year of age
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• densitometric analysis showed that type II wax diesters are significantly reduced relative to wild-type controls; the fatty acid composition of wax diesters is similar between groups
• the relative amount of the C20-1,2-diol is significantly reduced, whereas C16-1,2-diol is increased
• the concentrations of wax monoesters and sterols are significantly increased
• the amounts of sterol esters and triacylglycerols are not significantly different
• whereas surface lipids from wild-type mice start to become fluid at 36.0 +/- 0.2 C and are completely fluid at 42.4 +/- 0.5 C, mutant lipids start to become fluid at 40.2 +/- 1.6 C and are completely fluid at 52.4 +/-1.0 C
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• homozygotes exhibit functional defects of the sebaceous glands and hair follicle dystrophy that causes a progressive scarring alopecia
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• homozygotes exhibit a progressive hair loss starting at ~7 weeks of age, most often leading to a total loss of back hair at old age (22 months)
• hair loss begins mainly around the neck, but also at the ventral abdomen
• bald regions appear at the dorsal and ventral sides of some mice at ~5 months of age, and hair loss progresses in old age
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• although phenotypically normal at P10, homozygotes appear to have spiky hair around P50
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• at 1 year of age, hair follicles are dystrophic
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• at P53, the pilary canals are dilated and filled with sebum plugs composed of lipids (Oil Red O-positive material)
• by P86, dilation of the pilary canals by sebum plugs is increased such that interposed tissue is pinched and tissue remnants are expulsed into the stratum corneum
• however, no increased cellularity is seen in the dermis, indicating lack of an inflammatory response
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• at 1 year of age, most hair follicles are degenerating and the pilary canals gape wide open; remnants of hair follicles are associated with melanocytes apparently engaged in active melanogenesis
• by 2 years of age, hair follicles are rare in dorsal skin and associated with only a few sebocytes
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• the epidermis appears thicker at P86 and at 1 year of age
• however, no significant alterations in proliferation or differentiation are observed
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endocrine/exocrine glands
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• at P10, the area occupied by the sebaceous glands is 20% larger than that of wild-type controls
• sebaceous glands appear enlarged at P86 and at 1 year of age
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• densitometric analysis showed that type II wax diesters are significantly reduced relative to wild-type controls; the fatty acid composition of wax diesters is similar between groups
• the relative amount of the C20-1,2-diol is significantly reduced, whereas C16-1,2-diol is increased
• the concentrations of wax monoesters and sterols are significantly increased
• the amounts of sterol esters and triacylglycerols are not significantly different
• whereas surface lipids from wild-type mice start to become fluid at 36.0 +/- 0.2 C and are completely fluid at 42.4 +/- 0.5 C, mutant lipids start to become fluid at 40.2 +/- 1.6 C and are completely fluid at 52.4 +/-1.0 C
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homeostasis/metabolism
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• at P143, the sphingomyelin content is altered in both layers of the skin; C18- and C20-containing sphingomyelin is strongly reduced, accompanied by an increase in short chain sphingomyelin (C16)
• the molecular species composition of sphingomyelin remains unchanged in sebum
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• at P143, the levels of CerS4-specific C20-ceramides and also of C18-ceramides are reduced in the epidermis
• very-long-chain ceramides such as C22 to C24:1 are increased in the epidermis, whereas no significant changes in ceramide levels are observed in the dermis
• C18- and C20-hexosylceramide levels are significantly reduced in both layers of the skin
• only slight alterations of molecular species of ceramides containing C16, C18 and C22 are observed in sebum
• the molecular species composition of hexosylceramides remains unchanged in sebum
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