RESUMEN
Objective To investigate ultrahistopathological features of symmetrical acrokeratoderma.Methods Biopsy specimens were obtained from skin lesions and perilesional normalappearing skin of 6 patients with symmetrical acrokeratoderma,as well as from normal skin of 3 healthy volunteers.Then,these skin specimens were subjected to transmission electron microscopy (TEM).Results TEM showed obviously thickened stratum corneum,irregular morphology of keratinocytes and discontinuous cornified envelope.Aggregation and abnormal arrangement of keratin filaments occurred in all epidermal layers.Many vacuoles of different sizes were observed in the transitional zone between the stratum corneum and stratum granulosum.Hypogranulosis,abnormal shape and different sizes of keratohyalin granules,and reduction of membrane-coating granules were found in the stratum granulosum.Increased melanocytes with a large number of stage Ⅳ melanosomes in the cytoplasm were observed in the basal layers.Moreover,there was infiltration of a few lymphocytes in the superficial dermis.Perilesional normal-appearing skin tissues showed similar but milder ultrastructural changes.Conclusion Abnormal metabolism of keratins,epidermal differentiation complex proteins and lipids may exist in skin lesions of symmetrical acrokeratoderma,which may contribute to epidermal thickening and impairment of skin barrier function.
RESUMEN
Tissue samples from sheep oral epithelium of different age groups were fixed with three different fixatives to observe the ultrastructure of keratohyalin granules. Two conclusions were: 1. There were two types of keratohyalin granules in the sheep oral epithelium. The morphology and ultrastructure of type Ⅰ granules underwent alteration during epithelial development. The shape of granules changed from round to irregular by the combination with tonofilament bundles. Finally, the granules disappeared from several sites of mature oral epithelium. Type Ⅱ granules were round or oval in shape and were surrounded by free ribosomes. They did not have morphologic or ultrastructural changes during epithelial development. They appeared in immature oral epithelium, and constantly presented in mature epithelium. 2. According to the reaction of the two types of granules with the fixatives, it is suggested that the composition of type Ⅰ granules has the property of lipoprotein and the component of type Ⅱ granules possesses the nature of unsaturated lipid in addition to the lipoprotein.