integument
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• sulfur content of the hair fibers is reduced
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• hair shafts from the flank show multiple fractures, are twisted, crippled and bent, and locally thickened by numerous fusiform bulges
• hair shafts below the epidermis are composed of globular and discontinuous conglomerates of horny material
• most shafts fail to reach the epidermal surface and those that do are weak and fragile
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• pigment granules are only randomly detected in the hair cortex
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• missing irregularly in the zone of final hardening
• the cortex of the intrafollicular part of the hair shaft is always fragmented into globular and irregularly formed aggregates and includes unusual filamentous substances
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• missing irregularly in the zone of final hardening
• occupied by abnormal globular aggregates
• either discontinuous or more frequently totally absent
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• there is a prominent granular layer between the upper layers of the stratum spinosum and the nail plate
• the nail bed epithelium does not appear to be abnormal
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• the matrix region is severely altered
• some suprabasal cells show increased cytoplasm often associated with multiple intracytoplasmic vacuoles
• keratinocytes high in the spinous layer show striped cytoplasm
• the matrix zone is thinner and extends farther toward the distal tip of the nail
• the ventral epithelium of the proximal nail fold and the suprabasal cells of the nail matrix lack keratin 1 immunoreactivity and show abnormal expression of filaggrin
• keratohyalin granules of irregular size and shape are present in the cytoplasm of the suprabasal keratinocytes and insert into the aggregated tonofilaments disturbing filament aggregation
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• the nail plate is compact and narrows toward the tip of the nail
• the nail plate is markedly thinner at both the proximal nail fold and the tip of the nail
• nail plates consist of smaller, elongated superficial squames with slightly irregular surfaces and serrated borders
• the nail plate appears basophilic
• the dorsal nail plate separates from the hyponychium but bends toward the ventral side and breaks off
• sulfur content of the nail plate is reduced
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• blunt, broken, irregularly formed ends
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• severely shortened nails
• in most mice the nails terminate at the junction of the nail plate and the hyponychium
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• hair follicles in the zone of final hardening show pronounced pathological changes
• however, the number of hair bulbs is similar to controls
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• missing irregularly in the zone of final hardening
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• fibrils are more tightly packed than in controls
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• half-desmosomes attaching basal cells to the subjacent basal lamina are irregularly spaced with only scantly tonofilaments attached to them
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• cells contain only few and small bundles of tonofilaments
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• highly irregular, with areas of large piles of horny substances and projected corneocytes alternated with regions of only few and extremely attenuated corneous layers
• the lamellae are irregularly shaped and detached from one another, with intercellular contact lost over large areas
• the layer is loosened with increased distance from the granular layer
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• the skin surface looks rough because of bizarrely formed and projected corneocytes
• the interior of the corneocytes has an inhomogeneous appearance
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• markedly reduced number and thickness of tonofilament bundles
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embryo
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• the cervical duct has not narrowed and the third cleft covers only the dorsal part of the third branchial pouch at E1.5
• the ectoderm of the third cleft covers only the distal extremity and a small part of the cranial and caudal walls of the third pouch at E11.5
• at the end of the 11th day the pharyngo-branchial duct is reduced to a thin cord of cells that later disappears and the cervical duct also degenerates
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endocrine/exocrine glands
N |
• the structure of the parathyroid is identical to controls at E16 and E17
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• at E12 the ectoderm covers only the mid-portion of the ventral and external surfaces of the endoderm
• at E12.5 the primitive thymus is essentially endodermal with the ectodermal portion confined to the cranial region
• between E12 and E14 the volume of the thymus merely doubles rather than growing exponentially as in controls and the epithelial mass does not increase from E14 to E16
• at no time is the epithelium invaded by lymphoid cells
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immune system
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• at E12 the ectoderm covers only the mid-portion of the ventral and external surfaces of the endoderm
• at E12.5 the primitive thymus is essentially endodermal with the ectodermal portion confined to the cranial region
• between E12 and E14 the volume of the thymus merely doubles rather than growing exponentially as in controls and the epithelial mass does not increase from E14 to E16
• at no time is the epithelium invaded by lymphoid cells
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pigmentation
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• pigment granules are only randomly detected in the hair cortex
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hematopoietic system
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• at E12 the ectoderm covers only the mid-portion of the ventral and external surfaces of the endoderm
• at E12.5 the primitive thymus is essentially endodermal with the ectodermal portion confined to the cranial region
• between E12 and E14 the volume of the thymus merely doubles rather than growing exponentially as in controls and the epithelial mass does not increase from E14 to E16
• at no time is the epithelium invaded by lymphoid cells
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