Morphology of sweat glands in the skin of Saimaa (Pusa hispida saimensis) and Baltic ringed (Pusa hispida botnica) seals.

The endangered Saimaa ringed seal (Pusa hispida saimensis) is an endemic freshwater subspecies inhabiting Lake Saimaa in Finland. The Baltic ringed seal (Pusa hispida botnica) inhabits the brackish Baltic Sea, which is almost entirely landlocked. Recent research shows that Saimaa and Baltic ringed seals may be genetically even further apart from each other than from other ringed seal subspecies. We documented histologically the integument microstructure of Saimaa and Baltic ringed seals to determine whether the geographic and genetic isolation was manifested as variation in the integument microstructure of these subspecies adapted to icy aquatic environments. The skin structures of these subspecies were similar to those of other phocids. The association of the sweat glands with hair follicles in both subspecies suggested that they were small apocrine sweat glands described previously in terrestrial or aquatic mammals. None of the apocrine glands had large lumina, and some of the ducts were relatively straight and short. Further studies analysing the mode of secretion, for example, apocrine versus eccrine, in the sweat glands are necessary to confirm the types of sweat glands in seals.

Histomorphometrical study on the skin of different regions of the Caribbean common opossum (Didelphis marsupialis Linnaeus, 1758).

Common opossums (Didelphis marsupialis) are found throughout the Caribbean island of Trinidad and Tobago. The present work was conducted on the fresh normal skin of 10 common opossums and aimed to provide morphometric data and a histological description of the skin in different regions of the body. In the examined regions, the skin presented a typical thin skin morphology, with numerous folds on the surface. The dermis-epidermis junction is smooth, without the occurrence of dermal papillae. The average thickness of the opossum epidermis was 19.5 µm. The cranial region of the back showed the greatest epidermal thickness, and together with the other areas of the back presented an epidermis 2-3 times thicker compared with the other areas examined. To further confirm that the skin changes in the opossum are age- or diet-related, additional studies are required.

Histological and functional comparisons of four anatomical regions of porcine skin with human abdominal skin.

Because of the shortage of human skin for research purposes, porcine skin has been used as a model of human skin. The aim of this study was to identify the region of German Landrace pig skin that could be used as the best possible substitute for human abdominal skin. Porcine samples were collected from the ear, flank, back and caudal abdomen; human abdominal skin samples were excised during plastic surgery. Histological and ultrastructural assessments were carried out on the epidermis and dermis, with emphasis on the dermo-epidermal interface length, dermo-epidermal thickness ratio as well as densities of; hair follicles, arrector pili muscles, blood vessels and sweat glands. In the pig, the barrier function of the four anatomical regions was assessed. Results showed that both histologically and ultrastructurally, all four regions of porcine skin were similar to human skin. These include the shapes of keratinocytes, structure of cell contacts and presence of Weibel Palade bodies in endothelial cells. Other parameters such as the thickness of epidermis, the thickness of stratum basale, spinosum and granulosum and the number of cell layers in the stratum corneum were similar in human abdominal and in all four regions of porcine skin. However, there were also significant differences especially in the thickness of the stratum corneum, the dermo-epidermal interface length and the blood vessel density.

Comparison of density and output of sweat gland in tropical Africans and temperate Koreans.

Modification of sweating could be due to changes in activated sweat gland density (ASGD) and/or activated sweat gland output (ASGO). The present study determined regional and inter-ethnic differences in ASGD and ASGO during passive heating between tropical natives (African, n=22) and temperate natives (Republic of Korean, n=25). Heat load was carried out by immersing the half body into a hot water bath for 30min. Tympanic temperature (Tty) and skin temperature (Ts) were measured. Mean body temperature (mTb) was calculated. Sudomotor activities including sweat onset time, sweat rate, ASGD, and ASGO were examined in eight regions of the skin. Africans had smaller increase in mTb during passive heating than Koreans. The onset time of sweating was much more delayed in Africans compared to Koreans. In response to thermal load, ASGD and ASGO differed between body regions in Africans and Koreans. In most skin regions, ASGD and ASGO were lower in tropical Africans compared to those in temperate Koreans. Trunk portion including chest, upper back, lower back, abdomen had greater swear rate, ASGD, and ASGO compared to peripheral segments including upper arm, forearm, leg, and thigh in both ethnic groups. Distribution patterns of ASGD over the body appeared to be similar in both Africans and Koreans at the peak of thermal loading. In conclusion, the present study demonstrates that sudomotor activity in tropical Africans is reduced with lower ASGD and ASGO over the body surface compared to temperate Koreans.

Histological study of white rhinoceros integument.

In this study, we report findings from a microscopic analysis of the white rhinoceros (Ceratotherium simum) integumentary ultrastructure. Skin samples from the cheek, shoulder, flank and rump were taken from a 46-year-old female southern white rhinoceros and examined using H&E and elastic histological stains. The epidermis was thickest in the flank (1.003 mm) followed by the rump, cheek and shoulder. The stratum corneum comprised more than half the epidermal thickness. Numerous melanin granules were found in the basal and spinosum layers. The epidermal-dermal junction was characterized by abundant papillary folds increasing surface contact between integument layers. Most of the dermal thickness consisted of organized collagen bundles with scattered elastic fibers. Collagen fiber bundles were thickest in the flank (210.9 µm) followed by shoulder, rump and cheek. Simple coiled sweat glands were present in the dermis, but hair and sebaceous glands were absent. Together, these data suggest the white rhinoceros has a unique integumentary system among large terrestrial herbivores.

Selected Disorders of Skin Appendages--Acne, Alopecia, Hyperhidrosis.

This article reviewed some of the more common diseases of the skin appendages that are encountered in medicine: hyperhidrosis, acne, AA, FPHL, AGA, and TE. The pathophysiology behind the conditions and their treatments were discussed so that the clinician can make logical therapeutic choices for their affected patients.

High follicle density does not decrease sweat gland density in Huacaya alpacas.

When exposed to high ambient temperatures, mammals lose heat evaporatively by either sweating from glands in the skin or by respiratory panting. Like other camelids, alpacas are thought to evaporate more water by sweating than panting, despite a thick fleece, unlike sheep which mostly pant in response to heat stress. Alpacas were brought to Australia to develop an alternative fibre industry to sheep wool. In Australia, alpacas can be exposed to ambient temperatures higher than in their native South America. As a young industry there is a great deal of variation in the quality and quantity of the fleece produced in the national flock. There is selection pressure towards animals with finer and denser fleeces. Because the fibre from secondary follicles is finer than that from primary follicles, selecting for finer fibres might alter the ratio of primary and secondary follicles. In turn the selection might alter sweat gland density because the sweat glands are associated with the primary follicle. Skin biopsy and fibre samples were obtained from the mid-section of 33 Huacaya alpacas and the skin sections were processed into horizontal sections at the sebaceous gland level. Total, primary, and secondary follicles and the number of sweat gland ducts were quantified. Fibre samples from each alpaca were further analysed for mean fibre diameter. The finer-fibred animals had a higher total follicle density (P<0.001) and more sweat glands (P<0.001) than the thicker-fibred animals. The fibre diameter and total follicle density were negatively correlated (R(2)=0.56, P<0.001). Given that the finer-fibred animals had higher follicle density and more sweat glands than animals with thicker fibres, we conclude that alpacas with high follicle density should not be limited for potential sweating ability.

Hydrochromic conjugated polymers for human sweat pore mapping.

Hydrochromic materials have been actively investigated in the context of humidity sensing and measuring water contents in organic solvents. Here we report a sensor system that undergoes a brilliant blue-to-red colour transition as well as 'Turn-On' fluorescence upon exposure to water. Introduction of a hygroscopic element into a supramolecularly assembled polydiacetylene results in a hydrochromic conjugated polymer that is rapidly responsive (<20 µs), spin-coatable and inkjet-compatible. Importantly, the hydrochromic sensor is found to be suitable for mapping human sweat pores. The exceedingly small quantities (sub-nanolitre) of water secreted from sweat pores are sufficient to promote an instantaneous colorimetric transition of the polymer. As a result, the sensor can be used to construct a precise map of active sweat pores on fingertips. The sensor technology, developed in this study, has the potential of serving as new method for fingerprint analysis and for the clinical diagnosis of malfunctioning sweat pores.

Circular polarization induced by the three-dimensional chiral structure of human sweat ducts.

The upper part of the human eccrine sweat ducts, embedded within the epidermis layer, have a well-defined helical structure. It was recently suggested that, as electromagnetic entities, the sweat ducts interact with sub-mm waves [Y. Feldman et al., Phys. Rev. Lett. 100, 128102 (2008)]. Although correlation between changes in the reflectance spectrum in this frequency range and physiological activities has been shown, a direct link between the electromagnetic reflection and the helical structure itself has remained to be established. The fact that the sweat ducts manifest natural homochirality is henceforth used to produce this link. We report the detection of circular polarization asymmetry in the electromagnetic reflection from the human skin at sub-THz frequencies in vivo. We compare the results to numerical simulations and to measurements of a fabricated metamaterial. We argue that the observed circular dichroism can be interpreted uniquely as the signature of the helical structure itself. By twisting reflected electromagnetic waves, the human skin exhibits properties which are usually discussed only in the framework of metamaterial science.

Comparison of peripheral sudomotor sensitivity to acetylcholine in endurance and non-endurance trained male subjects.

INTRODUCTION: We investigated the effect of endurance and non-endurance training on peripheral sudomotor sensitivity. METHODS: The quantitative sudomotor axon reflex test (QSART) was performed. RESULTS: Endurance-trained subjects (ET, long-distance runners) had a significantly shorter onset time of sweating, greater sweat volume, increased density of activated sweat glands and sweat gland output per single activated gland, greater volume of transepidermal water loss, and higher skin temperature compared with those in the other 2 groups [non-endurance-trained group (NET), sedentary control group (CT)]. NET subjects (baseball players) had a tendency to increase in these variables; thus, some values were greater than control subjects. CONCLUSIONS: These results suggest that endurance training much more effectively modifies sudomotor sensitivity than non-endurance training.

Comparative histology and immunohistochemistry of porcine versus human skin.

BACKGROUND: Porcine skin is increasingly being employed as a model of human skin in various research fields, including pharmacology, toxicology and immunology, with particular interest in percutaneous permeation and organ transplantation. Porcine skin shows several anatomical and physiological similarities, but also some differences, with human skin, but few in depth comparative studies are so far available. OBJECTIVES: To study the immunohistochemical properties of normal porcine skin in comparison with human skin. MATERIALS AND METHODS: We performed a histological and immunohistochemical study on frozen and formalin-fixed, paraffin-embedded skin biopsies from domestic swine and normal human skin, using a panel of 93 monoclonal or polyclonal antibodies recognizing various human and porcine skin cell types or structures. RESULTS: We found that several antibodies used to detect normal human skin cells showed equivalent immunoreactivity on normal porcine skin. However, some antibodies commonly used to detect human skin antigens remained unreactive on porcine skin. CONCLUSIONS: Our findings highlight the main immunohistochemical properties of porcine skin in comparison with those of human skin and provide a morphological and immunohistochemical basis useful to researchers using porcine skin.

Morfologia, ultraestrutura e morfometria do tegumento da paca (Cuniculus paca Linnaeus, 1766) criada em cativeiro / Morphology, ultrastructure and morphometry of the tegument of paca (Cuniculus paca Linnaeus, 1766) raised in captivity

Considerando-se a falta de informações detalhadas sobre a morfologia da paca, sendo o segundo maior roedor da fauna brasileira, de excelente qualidade de carne e, dada a importância do tegumento comum, inclusive para o bom manejo em cativeiro, e até mesmo estudos como uma opção de animal de experimentação, descreveu-se a morfologia, morfometria e a ultraestrutura da pele de oito pacas (Cuniculus paca) machos e fêmeas, mediante a análise comparativa de segmentos cutâneos das regiões cervical, dorsal e medial do carpo. Observaram-se macroscopicamente as características da pelagem. Parte dos segmentos das regiões cutâneas foi analisada à microscopia de luz e parte, à microscopia eletrônica de varredura. Mensuraram-se as espessuras da derme, epiderme, camada córnea, perfis das fibras de colágeno da derme reticular e a área dos perfis das células das glândulas sebáceas repletas. Analisaram-se os resultados pela estatística descritiva e teste "T" (p<0,001). A coloração da pelagem da paca é castanho avermelhado com cerdas organizadas em grupos. A arquitetura da cútis e os anexos cutâneos se assemelham aos dos mamíferos em geral, embora haja ausência de glândulas sudoríparas. De acordo com a analise morfométrica, pôde-se inferir que a arquitetura da cútis de pacas machos e fêmeas apresenta diferenças quando comparada entre os sexos e também em um mesmo animal, diferenciando-se entre diversas regiões corpóreas.

Considering the lack of detailed information about the morphology of paca, which is the second largest rodent of Brazilian's fauna, with excellent meat quality and, due to the importance of the common integument, we described the morphology, ultrastructure and morphometry of the skin of eight pacas (Cuniculus paca), males and females, through comparative analysis of skin's segments of the cervical, dorsal and medial carpal portions. Macroscopic characteristics of the coat were studied. Part of the segments of cutaneous regions was analyzed by light microscopy, and the other part by scanning electron microscopy. We measured the thickness of dermis, epidermis, stratum corneum, the profiles of the collagen fibers of reticular dermis and the area of filled sebaceous gland cells. The results were analyzed by descriptive statistics and "T" test (p<0.001). The color of the coat is reddish brown with bristles arranged in groups. The architecture of the skin and skin appendages resembles those of mammals in general, although there are no sweat glands. According to the morphometric analysis, this study shows differences of the skin architecture between male and female pacas and also between various body regions in the same animal.

[The morphogenesis of mammalian cutaneous glands in evolutionary perspective].

The morphogenesis of mammalian cutaneous glands is considered based on the analysis of the literature and our own original data with the focus on the issues of gland polymorphism and specific features in postnatal development (from the case study of circumanal hepatoid glands of newborn domestic dogs), including the features reflecting the evolutionary relationships of various types of cutaneous glands. The hepatoid glands are a component of the glandular complex ofthe hair follicle, which also includes sebaceous and sweat glands; have a specific structure; and produce protein secretion by a merocrine pathway. Characteristic of these glands are wide polymorphism, sex- and age-related differences in the degree of development, occurrence in only a few phylogenetically related mammalian taxa (even-toed ungulates and carnivores); and a signaling type of their secretion. The data support the "generative concept," relying on the idea of a separate and independent origination of diverse derivatives of the external integuments.

Modeling of reflectometric and ellipsometric spectra from the skin in the terahertz and submillimeter waves region.

The human skin is modeled as a stack of homogeneous layers in the terahertz and submillimeter waves regions with some anisotropy due to the helical sweat glands and other elongated entities. A dielectric model for the skin is presented, valid for a wider frequency range (up to the terahertz region) taking into account the dispersive nature of the effective conductivity. Polarized reflectivity and generalized ellipsometric parameters are calculated versus angle and wavelength. Recent studies have claimed that the helical sweat ducts act as an array of low-Q helical antennae and are dominant in shaping the spectral response in the sub-terahertz region. We found that water absorption, dispersion and multiple interference effects play the major role in shaping the spectrum without the need for the assumption of the sweat ducts acting as low-Q helical antennae. High sensitivities to the water content are found particularly in the ellipsometric parameters at large incidence angles. Hence a new methodology is proposed to detect skin cancer using variable angle ellipsometry or polarized reflectometry. The parameter found with the highest sensitivity to water content is cos Δ(pp) with Δ(pp) being the phase of the on-diagonal reflection matrix ratio between p-to-p polarization.

Skin and coat traits in sheep in Brazil and their relation with heat tolerance.

The objective of this study was to evaluate and compare physical parameters in groups of sheep with different phenotypic characteristics in the Centre-west region of Brazil. Five groups of sheep, with nine animals per group, were selected, three groups of Santa Inês animals with different coat colours (white, brown and black), one group with crossbred animals (Santa Inês × Bergamasca) and one group with animals of the Bergamasca breed. The following traits were evaluated: coat thickness, number and length of hair, pigmentation level in the coat and the skin as well as the percentage area of sweats glands in the skin tissue, carried out by histological analysis. The number of hairs and the area of sweats glands were not significantly different between the evaluated groups. The Bergamasca breed showed low pigmentation of the skin and long hairs. The levels of pigmentation of the hair and of the skin were highly correlated. Between the Santa Inês groups, the group with white hair showed the better parameters for heat adaptation, while the brown hair group showed the lower heat adaptation when compared with another hair breed groups.

Model-based quantitative laser Doppler flowmetry in skin.

Laser Doppler flowmetry (LDF) can be used for assessing the microcirculatory perfusion. However, conventional LDF (cLDF) gives only a relative perfusion estimate for an unknown measurement volume, with no information about the blood flow speed distribution. To overcome these limitations, a model-based analysis method for quantitative LDF (qLDF) is proposed. The method uses inverse Monte Carlo technique with an adaptive three-layer skin model. By analyzing the optimal model where measured and simulated LDF spectra detected at two different source-detector separations match, the absolute microcirculatory perfusion for a specified speed region in a predefined volume is determined. qLDF displayed errors<12% when evaluated using simulations of physiologically relevant variations in the layer structure, in the optical properties of static tissue, and in blood absorption. Inhomogeneous models containing small blood vessels, hair, and sweat glands displayed errors<5%. Evaluation models containing single larger blood vessels displayed significant errors but could be dismissed by residual analysis. In vivo measurements using local heat provocation displayed a higher perfusion increase with qLDF than cLDF, due to nonlinear effects in the latter. The qLDF showed that the perfusion increase occurred due to an increased amount of red blood cells with a speed>1 mm∕s.

The orbitofacial glands of bats: an investigation of the potential correlation of gland structure with social organization.

The facial glands of bats are modified skin glands, whereas there are up to three different orbital glands: Harderian, lacrimal, and Meibomian glands. Scattered studies have described the lacrimal and Meibomian glands in a handful of bat species, but there is as yet no description of a Harderian gland in bats. In this study we examined serial sections of orbitofacial glands in eight families of bats. Much variation amongst species was observed, with few phylogenetic patterns emerging. Enlarged facial glands, either sudoriparous (five genera) or sebaceous (vespertilionids only) were observed. Meibomian and lacrimal glands were present in most species examined (except Antrozous), though the relative level of development varied. Two types of anterior orbital glands were distinguished: the Harderian gland (tubulo-acinar: observed in Rousettus, Atribeus, Desmodus and Miniopterus) and caruncular (sebaceous: observed in Eptesicus and Dieamus). The relative development of the nasolacrimal duct and the vomeronasal organ did not appear to be correlated with the development of any of the exocrine glands examined. There does, however, appear to be a correlation between the presence of at least one well developed exocrine gland and the level of communality and known olfactory acuity, best documented in Artibeus, Desmodus, and Miniopterus.

Use of heat tolerance traits in discriminating between groups of sheep in central Brazil.

The animal and its environment make up an integrated system, where each acts on the other. Tropical regions are characterized by high levels of solar radiation and environmental temperature which may adversely affect animal production. This study carries out a multivariate analysis of physical and physiological traits in sheep in the Federal District of Brazil to test the ability to separate groups of animals and determine which traits are most important in the adaptation of animal to heat stress. The variables studied included coat thickness, number and length of hairs, pigmentation of the skin and coat, number of sweat glands as well as heart and respiratory rates, rectal and skin temperatures, sweating rate, and blood parameters. Five groups of ten animals were used depending on breed (Bergamasca, crossbred, or Santa Inês) or coat color (Santa Inês--brown, white, and black). The data underwent multivariate statistical analyses including cluster, discriminate, and canonical, using Statistical Analysis System--SAS®. The tree diagram showed clear distances between groups studied and canonical analysis was able to separate individuals in groups, especially Bergamasca and white Santa Inês. The canonical correlation redundancy analysis showed that coat reflectance as well as hair length and number of hairs per unit area were the most useful in explaining changes in physiological traits. Skin and coat traits such as hair length, coat reflectance, percentage of epithelial area occupied by sweat glands, skin reflectance and thickness, as well as heart and breathing rates were the most important in separating these groups.

Characteristics of refractory sweating areas following minimally invasive surgery for axillary hyperhidrosis.

BACKGROUND: Several surgical strategies have evolved for the treatment of focal axillary hyperhidrosis (FAH). However, nonresponders are found in every procedure. Until now no characterization of the recurrent sweating areas has been reported. The aim of this study was to characterize the axillary sweat area by using the iodine starch test in nonresponders prior to surgery. METHODS: Prior to minimally invasive surgery, 24 (15 females, 9 males) nonresponders underwent a repetitive iodine starch test to define the area of recurrent sweating. Size and distribution of the hyperhidrotic area were documented. RESULTS: Eighteen patients had undergone previous liposuction and six liposuction curettage. The size of recurrent sweating area was 10.2 cm(2) (range = 5.5-24.5 cm(2)). We were able to identify three different patterns of recurrent sweating: crescent (33%), circular (41%), and insertion-spot type (26%). CONCLUSION: Patterns of recurrent sweating areas may partially indicate insufficient planning and implementation of surgery, resulting in nonresponders. We suggest that exact preoperative identification of the hyperhidrotic area be mandatory.

Human skin as arrays of helical antennas in the millimeter and submillimeter wave range.

Recent studies of the minute morphology of the skin by optical coherence tomography showed that the sweat ducts in human skin are helically shaped tubes, filled with a conductive aqueous solution. A computer simulation study of these structures in millimeter and submillimeter wave bands show that the human skin functions as an array of low-Q helical antennas. Experimental evidence is presented that the spectral response in the sub-Terahertz region is governed by the level of activity of the perspiration system. It is also correlated to physiological stress as manifested by the pulse rate and the systolic blood pressure.