The skin of primates. XLIV. Numerical taxonomy of primate skin

Data on 84 characteristics of the skin of 36 species of primates were extracted from a series of articles describing the histological and histochemical properties of the skin of primates. The data were subjected to a cluster analysis. The results were in reasonably good agreement with orthodox primate taxonomies although some exceptions were apparent. The species clustered into four main groups approximately comparable to Prosimii, Cercopithecoidea, Ceboidea, and Hominoidea. The internal arrangements of the Prosimii, Cercopithecoidea, and Hominoidea are commensurate with standard taxonomic practice. Within the Ceboidea, however, the Atelinae and Alouattinae tend to group with the Hominoidea, Aotus and Saimiri show variable placements, and Callimico groups with the Callithricidae.     

Osteopontin expression in normal skin and non-melanoma skin tumors.

Osteopontin (OPN) is an adhesive, matricellular glycoprotein, whose expression is elevated in many types of cancer and has been shown to facilitate tumorigenesis in vivo. To understand the role of OPN in human skin cancer, this study is designed to determine whether OPN is expressed in premalignant [solar/actinic keratosis (AK)] and in malignant skin lesions such as squamous cell carcinomas (SCC) and basal cell carcinomas (BCC), as well as in normal skin exposed or not exposed to sunlight. Immunohistochemical analyses showed that OPN is expressed in SCC (20/20 cases) and in AK (16/16 cases), which are precursors to SCC, but is absent or minimally expressed in solid BCC (17 cases). However, positive staining for OPN was observed in those BCC that manifest differentiation toward epidermal appendages such as keratotic BCC. In sunlight-exposed normal skin, OPN is minimally expressed in the basal cell layer, but in contrast to those not exposed to sunlight, OPN is more prominent in the spinous cell layer with increasing intensity toward the granular cell layer. Additionally, OPN is expressed in the hair follicles, sebaceous glands, and sweat glands of normal skin. In conclusion, these data suggest that OPN is associated with keratinocyte differentiation and that it is expressed in AK and SCC, which have metastatic potential, but minimally expressed in solid BCC.     

The skin of primates. XXX. The skin of the woolly monkey. (Lagothrix lagotricha)

The anatomical and histochemical features of the skin of the woolly monkey are intermediate between those of the Cercopithecoidea and the Pithecoidea. The animal has a prehensile tail, the glabrous, friction surface of which is similar to that of the fingers. The epidermis is heavily pigmented. The dermal vascularization is relatively well-developed and similar to that of the skin of the Cercopithecoidea. Hair follicles grow in groups of 4 to 15, as in the skin of the Pithecoidea. In the hairy skin, eccrine sweat glands occur only in the tail and genitalia. The woolly monkey, like the green monkey, possesses only acetylcholinesterase-containing nerve fibers around its eccrine sweat glands.     

Mechanism of skin morphogenesis. II. Retinoic acid modulates axis orientation and phenotypes of skin appendages.

The factors that determine the axial orientation and phenotypes of skin appendages were analyzed by studying the effect of retinoic acid (RA) on embryonic chicken skin explant cultures. With RA uniformly distributed in the culture media, the feather buds became smaller, were disoriented or were transformed into scale-like structures in a concentration-dependent manner (from 0.05-2.5 microM). With RA distributed as a gradient created by a RA-soaked anion exchange bead, a radial zone of inhibition with a rim of disoriented buds was observed. The new axis of the disoriented buds appeared to be determined by a combination of the original feather axis determining force and a new axial force pointing centrifugally away from the RA source. This observed result can be simulated with a computer model using a vectorial sum of different feather axial determination forces. The size of the inhibited zone is linearly correlated to the RA concentration and may be used to quantify the morphogenetic activity of retinoids. These effects are specific to developmental stages (Hamburg and Hamilton stage 31-34). Both all-trans and 13-cis RA have morphogenetic activity. Retinol has no effect and retinal has a small inhibitory effect but neither phenotypic transformation nor axial disorientation were observed. The antero-posterior gradient of homeoprotein XlHbox 1 in feather buds became diffusive after RA treatment. RA dissolves dermal condensations and the distribution of N-CAM is altered from an anterior localized pattern to a diffusive presence in the bud cores. Endogenous retinoids in developing skins show developmental stage-dependent changes both quantitatively and qualitatively. The results suggest that RA either is or can modulate the endogenous morphogen(s) that determine the orientation and phenotype of skin appendages, and that this morphogenetic pathway involves Hox genes and adhesion molecules.