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.     

The skin of primates. 33. The skin of the Angwantibo (Arctocebus calabarensis)

The general behavior, locomotion, and body from of the angwantibo resemble those of Loris and Nycticebus. Its skin, however, is similar to that of Pottos and Galagos; singular among the similarities is the occurrence of alkaline phosphatase-positive dendritic cells in the epidermis. The presence of elongated, sausageshaped end-organs in the mucocutaneous region, the absence of arrector pili muscle, and the absence of alkaline phosphatase in the hair follicle nerve end-organs are distinctive features of angwantibos. These animals have a well-formed, complete nictitating membrane, thereby differing from all other primates studied.     

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.     

The skin of primates. XXXVII. The skin of the pig-tail macaque (Macaca nemestrina)

The skin of the pig-tail macaque is basically similar to that of the rhesus monkey and the stump-tail macaque. The epidermis is thin and contains occasional basal melanocytes. The dermis, rich in elastic fibers, is practically free of pigment-containing cells. The upper dermis is highly vascular in the perianal region and sex skin. Cholinesterase-reactive nerve endings are plentiful beneath the friction surfaces of the pes and manus, mucous membranes, and junction of the hairy gluteus and glabrous ischial callosity. Hederiform-like endings are present in the eyelid, pinna, and frontal scalp. Apocrine and eccrine sweat glands occur throughout the hairy skin in a 2–3: 1 ratio. Both types are invested by nerves reactive for acetyl- and butyrylcholinesterase.     

The skin of primates. XXXIX. The skin of the white-browed capuchin (Cebus albifrons)

The skin of the white-browed capuchin (Cebus albifrons), although basically similar to that of the squirrel monkey (Saimiri sciureus), contains several outstanding peculiarities: (1) both the epidermis and dermis of the general body surface are devoid of melanotic melanocytes; (2) the skin of the prehensile tail has no modified, glabrous friction surface; (3) the prehensile surface of the tail has no specialized nerve end-organs; (4) cholinesterase-positive, papillary nerve end-organs rest beneath the epidermal ridges of volar skin; and (5) both the clear cells and dark cells of the eccrine glands contain glycogen but neither shows phosphorylase activity.     

The skin of primates. XXXVI. The skin of the pigmy marmoset--Callithrix (Cebuella) pygmae

The pigmy marmoset — Callithrix (= Cebuella) pygmaea Spix — is the second detailed study of the members of the family Callithricidae. It is closely allied to the red-mantled tamarin — Saguinus (=Tamarinus) fuscicollis illigeri Spix — and shares some of its characteristics with both Prosimii and Anthropoidea. The epidermis and dermis contain moderate numbers of concurrent, melanotic melanocytes. The dermis is rich in elastin. Hair follicles grow in groups of three or four over the general body surface, and one apocrine gland is associated with each grouping. Arrectores pilorum muscles are well developed. On the ventral ulnar wrist are sinus hairs associated with apocrine glands. Most hair follicles have nerve end-organs around them that are reactive for acetylcholinesterase and alkaline phosphatase. There is a large aggregation of sebaceous glands in the suprapubic region. The large sebaceous glands in the eyelid, face, and external genitalia are surrounded by cholinesterasereactive nerves. Apocrine glands are found over most of the hairy skin except the brow, scalp and back; a large grouping of them is present in the sternal region. Only the secretory coils of apocrine glands in the external genitalia are invested with butyrylcholinesterase-rich nerves. Eccrine glands are confined to the volar surfaces of the pes and manus. They have dark cells with abundant glycogen and clear cells with neither glycogen nor PAS-reactive material. The nerves around the eccrine secretory coil are reactive only for acetylcholinesterase.     

The skin of primates. XXXI. The skin of the black-collared tamarin (Tamarinus nigricollis)

The black-collared tamarin represents the first detailed study of a member of the family Callithricidae. Although certain features are unique, some of its characteristics resemble those of Prosimii and those of Anthropoidea. The epidermis is moderately pigmented, and the dermis contains numerous elestic fibers. Scattered melanocytes are found throughout both layers. Hair follicles grow in groups of 3 to 4 over the general body surface, including the muzzle. One apocrine gland is associated with each hair group. In the periinguinal region is a large concentration of gigantic sebaceous glands. Apocrine glands occur over the entire hairy skin. Aggregations of these glands on the ventral wrist (in conjunction with sinus hairs) and chest represent the ulnar gland and suprasternal gland, respectively. Apocrine secretory coils of the ulnar gland and external genitalia are surrounded by melanotic, dendritic melanocytes. Eccrine sweat glands are confined to the volar surfaces of the pes and manus. Cholinesterase-reactive granules are dispersed throughout the cytoplasm of the myoepithelial cells.     

The skin of primates. XXIX. The skin of the pigmy bushbaby (Galago demidovii)

The skin of the pigmy bushbaby (Galago demidovii), the smallest existing prosimian, is largely similar to that of the other African Lorisidae, although this animal has certain peculiar features. The very thin epidermis contains alkaline phosphatase-reactive dendritic cells which resemble those in the other bushbabies and the potto. The hair follicles of this animal are similar to those of the lesser bushbaby, while the sebaceous glands are different from those of the other bushbabies in being reactive for alkaline phosphatase. The histological and histochemical properties of the sweat glands are similar to those of the other bushbabies.     

The skin of primates. 38. The skin of the red uacari (Cacajao rubicundus)

The skin of the red uacari (Cacajao rubicundus) is characterized by distinctive traits. Pigmentation of both the epidermis and dermis in juvenile animals resembles a similar condition recorded in adult Callithricidae. Extensive capillary sinuses pervade the upper dermis of the face, ears, forehead, and frontal scalp. Hederiform nerve endings are common in the face and scalp, as are papillary nerve endorgans in the volar friction surfaces; both are reactive for specific and pseudocholinesterase. A general diminution in size of hair follicles and a retarded generative cycle contribute to the phenomenon of “baldness” in the forehead and scalp of mature animals. Apocrine glands are quantitatively diminished over the dorsum. Eccrine sweat glands, confined to the palmar and plantar friction surfaces, are poorly differentiated; all secretory cells contain glycogen.     

The skin of primates. XXXIV. The skin of the golden spider monkey (Ateles geoffroyi)

The skin of the golden spider monkey (Ateles geoffroyi) has many histological and histochemical similarities to that of the woolly monkey (Lagothrix lagotricha) and howler monkey (Alouatta caraya); however, this monkey possesses certain peculiar properties such as large sebaceous glands, a combined distributional pattern of eccrine and apocrine sweat glands, and abundant alkaline phosphatase in the sebaceous glands, apocrine and eccrine sweat glands. In brief, the anatomical and histochemical properties of the skin of this animal are more similar to those of the howler monkey than to the woolly monkey. In addition, the skin of these three Ceboids falls phylogenetically between that of the Cercopithecoidea and Pithecoidea.     

Subcutaneous mastectomy. The excess skin problem.

Subcantaneous mastectomy through a lateral approach, with preservation of the nipple and areola on a dermal pedicle, removing the excess skin at the time of aubautaneous mastectomy, is a safe procedure which results in esthetically acceptable breasts. The surgical approach greatly facilitates the removal of the entire glandular portion of the breast. The need for a second surgical procedure is eliminated. Lateral biopsy scars can be reinforced by the dermal sling support, thereby decreasing the chances of exposure of the implant. The implant is also successfully and easily held in position by the use of the dermal-fat sling support. The nipple and areola survive quite well on the dermal pedicle, with preservation of contractility and sensation, as well as of blood supply.     

The skin of primates. XLI. The skin of the silver marmoset—Callithrix (= Mico) Argentata

The skin of the silver marmoset, Callithrix (= Mico) argentata Linnaeus, has many outstanding characteristics. The unusually thin epidermis and dermis are generally devoid of melanotic melanocytes. The surface of the interramal gular region is peppered with small, elevated papillae; that of the corpus penis is characterized by keratinized, proximally directed hollow spines in whose cavities are organized nerve end-organs and capillary loops. Cholinesterase-reactive papillary nerve end-organs and Meissner corpuscles populate all volar friction surfaces. A highly vascular dermis and subcutaneous fat pad partially contribute to the characteristic rubicund color of the face, external ears, and anogenital region. Many body surface hairs are accompanied by the classic Haarscheibe of Pinkus. Sinus hairs are plentiful; a circumscribed vibrissa-bearing eminence is located on the ventral ulnar aspect of each wrist. Alkaline phosphatase-positive, stellate-shaped cells are found on the outer root sheath and epithelial sac of active and quiescent hairs in all cephalic regions; such cells are not argyrophilic, aurophilic, or osmiophilic. Hairs grow in linear perfect sets of 3 to 5 follicles; they do not grow singly on the cheek. Large sebaceous glands contain alkaline phosphatase in their peripheral acini; extensive fields of gigantic multilobular sebaceous glands contribute to the distinct, opaque-white color of the scrotal skin. Numbers of apocrine sweat glands are diminished in cephalic regions but one gland occurs with each hair follicle in the axilla, scrotum, suprapubic region, and ulnar eminence. Relatively avascular eccrine sweat glands are confined to the volar friction surfaces. Their secretory coils contain sporadically distributed glycogen and phosphorylase and surrounding nerves are much more reactive for acetyl- than butyrylcholinesterase.     

The skin of primates. XL. The skin of the cottontop pinché Saguinus (=Oedipomidas) oedipus

The skin of Saguinus (= Oedipomidas) oedipus Linnaeus, is basically similar to that of the red-mantled tamarin, Saguinus (= Tamarinus) fuscicollis Spix; it has several peculiarities: (1) a circumscribed tuft of vibrissae on the ulnar aspect of the wrist; (2) an accumulation of apocrine glands over the sternum; and (3) an extensive posterior abdominal field of gigantic sebaceous glands admixed with large apocrine glands, better developed in the female. The epidermis, dermis, hair follicles, sebaceous ducts, and apocrine excretory ducts are all heavily pigmented. Hairs are arranged in linear perfect sets; the epithelial sac of quiescent follicles is devoid of glycogen and phosphorylase. Eccrine sweat glands are restricted to the volar friction surfaces and contain no glycogen. Only the coiled excretory ducts of the eccrine glands contain phosphorylase. All cutaneous nerve fibers are more reactive for acetylthan butyrylcholinesterase.     

The skin as an immune organ.

As a protective interface between internal organs and the environment, the skin encounters a host of toxins, pathogenic organisms, and physical stresses. To combat these attacks on the cutaneous microenvironment, the skin functions as more than a physical barrier: it is an active immune organ. Immune responses in the skin involve an armamentarium of immune-competent cells and soluble biologic response modifiers including cytokines. Traversed by a network of lymphatic and blood vessels, the dermis contains most of the lymphocytes in the skin, other migrant leukocytes, mast cells, and tissue macrophages. Although the epidermis has no direct access to the blood or lymphatic circulation, it is equipped with immune-competent cells: Langerhans cells, the macrophage-like antigen-presenting cells of the epidermis; keratinocytes, epithelial cells with immune properties; dendritic epidermal T lymphocytes, resident cells that may serve as a primitive T-cell immune surveillance system; epidermotropic lymphocytes, migrants from vessels in the dermis; and melanocytes, epidermal pigment cells with immune properties. Although the components of the epidermis and dermis work in concert to execute immune responses in the skin, for purposes of this review, we focus on the cells and cytokines of the epidermal immunologic unit, the frontline of immune protection against environmental toxins and microbes.