Hydradermabrasion through the lens of Line-Field Confocal Optical Coherence Tomography.

BACKGROUND: Hydradermabrasion, also known as "HydraFacial," is an exfoliative cosmetic procedure for skin rejuvenation that has gained popularity. Despite its increasing popularity, clinical studies validating its efficacy with non-invasive assessment of histological changes to the skin, are scarce. In this study, we used Line-Field Confocal Optical Coherence Tomography (LC-OCT), an optical imaging device, to non-invasively visualize microscopic changes to skin anatomy after hydradermabrasion treatment. MATERIALS/METHODS: Eight volunteers (Fitzpatrick skin types II-V) were recruited for this study. Images, using LC-OCT (DeepLive, DAMAE medical) were obtained before and after hydradermabrasion and at 2 weeks post-treatment. A commercially available hydradermabrasion device was utilized to perform the dermabrasion. RESULTS: In the epidermis, initially, a decrease in the average thickness of the stratum corneum, from 9.42 to 6.67 µm was visualized in LC-OCT images after hydradermabrasion. However, at 2 weeks of follow-up, the average stratum corneum thickness was 9.75 µm, resulting in an overall increase in the average thickness after treatment. Improved homogenization of the stratum corneum and decreased number of undulations in the epidermis post-treatment were also visualized. In all the subjects, the superficial dermis appeared stretched, which returned to baseline by the 2-week follow-up. At the 2-week follow-up, there were no visible differences in the quality and quantity of collagen fibers in the dermis. CONCLUSION: In our study, LC-OCT images of the epidermis and dermis demonstrated microscopic features of skin rejuvenation when treated with hydradermabrasion. Thus, not only highlighting the efficacy of hydradermabrasion but also the potential of LC-OCT to serve as a tool for visualizing the microscopic effects of cosmetic procedures on skin anatomy.

Cellular patterning and cyto-architectural organization of the skin of electric catfish (Malapterurus electricus, Siluriformes) with a particular emphasis on its ampullary electroreceptor.

The functional morphology of the skin of Malapteruridae is presumably evolved to cope with a diversified range of ambient physiological, environmental, and behavioral conditions. Herein, we firstly characterized the microstructures and intriguing patterning of the skin of twelve adult electric catfish (Malapterurus electricus, Malapteruridae) using histological, histochemical, immunofluorescent, and ELISA standard methodology. The skin comprises three sequentially-oriented layers: the epidermis, dermis, and hypodermis with a significantly increased thickness of the former. The epidermis contains four types of cells: the surface epithelial cells, mucous cells, granular cells, and club cells. We defined distinctive ampullary electroreceptors in the outer epidermis that possess flask-shaped sensory crypt containing electroreceptor cells together with vertical collagen rods. Dermis and hypodermis are composed of connective tissue; however, the former is much more coarse and dense with comparable reactivity for Masson-Goldner trichrome (MT). Placing our data in the context of the limited body of previous work, we showed subtle changes in the expression of mucin subunits together with cytoskeletal fractions of collagens, myosin, F-actin, keratins, and tubulins. Taken as a whole, our results convincingly showed that the skin of M. electricus shares some structural similarities to other Siluriformes, however, it has some functional modifications that are implicated in protection, defense, and foraging behavior.

Histological changes of the skin during postembryonic development of the crested newt Triturus ivanbureschi (Urodela, Salamandridae).

BACKGROUND: Amphibian skin has been studied for many decades, especially the metamorphic changes in the skin of frogs. Less attention has been paid to salamander skin. Here, we describe changes in the skin structure during postembryonic development in a salamandrid species, the Balkan crested newt Triturus ivanbureschi. METHOD: Using traditional histological techniques we examined the skin in the trunk region of three premetamorphic larval stages (hatchling, mid larval and late larval) and two postmetamorphic stages (juvenile, just after metamorphosis, and adult). RESULTS: In larval stages, skin consists only of the epidermis, which gradually develops from the single epithelial cell layer in hatchlings, to a stratified epidermis with gland nests and characteristic Leydig cells at the late larval stage. During metamorphosis, Leydig cells disappear, and the dermal layer develops. In postmetamorphic stages, skin is differentiated on stratified epidermis and the dermis with well-developed glands. Three types of glands were observed in the skin of the postmetamorphic stages: mucous, granular and mixed. Gland composition appears to be stage- and sex-specific, with juveniles and adult female being more similar to each other. In juveniles and adult female, there are a similar proportion of glands in both dorsal and ventral skin, whereas in adult male granular glands dominated the dorsal skin, while mixed glands dominated the ventral skin. CONCLUSION: Our results provide a baseline for future comparative research of skin anatomy in salamanders.

Morphology of coat and skin of small ruminants reared in the Brazilian semi-arid region.

The structure of the coat and integument of small ruminants reared in semi-arid regions have valuable characteristics that favor their adaptation to the region. The objective of this study was to evaluate the structural characteristics of the coat and integument and sweating capacity of goats and sheep in the Brazilian semi-arid region, using 20 animals, 10 of each breed, 5 males and 5 females of each species, grouped in a completely randomized design in a 2 x 2 factorial scheme (2 species and 2 genders) with 5 replicates. The animals were already being kept under the influence of high temperatures and levels of direct solar radiation before the day of the collections. At the time of the evaluations, ambient temperature was high, with low relative humidity. The pattern of epidermal thickness and sweat glands per body region was superior in sheep (P < 0.05), and the number of hair follicles and sweat rate were similar (P > 0.05) between the species. There was no difference (P > 0.05) in the evaluated characteristics between the genders, showing that they are not influenced by hormones. The morphology of the coat and skin of these animals showed a superiority of goats compared to sheep.

Morphological pattern of the dermal denticles of the Southern sawtail catshark Galeus mincaronei Soto, 2001.

Dermal denticles cover the skin of sharks for protection and may have additional functions, depending on the environment. The aim of the present study was to analyze the morphological pattern of dermal denticles across the body of the poorly known deep-water catshark Galeus mincaronei, which is endemic to Southern Brazil. Additionally, we aimed to identify differences between sexes and stages of sexual maturity. For this purpose, we analyzed patches of eight skin samples from body regions, that is, the head, body, and tail. Dermal denticles were imaged using scanning electron microscopy. Measurements of crown morphological variations (length and width) and density of dermal denticles were performed. Nine characters of dermal denticle morphology were selected to describe a morphological pattern using principal component analysis (PCA). The first PCA axis explained 45.2% of the variation, the second explained 33%, and the third explained 14.3%, together explaining 92.5% of the total variation in denticle morphology. We identified three groups of dermal denticle crown morphologies and their possible functions. The first was composed of nostril and snout denticles, which might suggest abrasion strength functions; the second was composed of most body denticles, such as those in the cranium, on the left side of the body, and on the pectoral, dorsal, and caudal fins, which might be related to generalized functions; and the third was composed of only caudal crest denticles, which might indicate defense functions with hydrodynamic properties in G. mincaronei. Likewise, our results reveal variations in dermal denticle morphology and arrangement along the three maturity stages considered in both sexes. Similarly, sexual dimorphism in the crown width and morphology of dermal denticles was observed in developing and mature individuals. Our results are the first to reveal the morphological variation of dermal denticles in relation to function, sex, and ontogeny of individual G. mincaronei.

Unravelling the structural variation of lizard osteoderms.

Vertebrate skin is a remarkable organ that supports and protects the body. It consists of two layers, the epidermis and the underlying dermis. In some tetrapods, the dermis includes mineralised organs known as osteoderms (OD). Lizards, with over 7,000 species, show the greatest diversity in OD morphology and distribution, yet we barely understand what drives this diversity. This multiscale analysis of five species of lizards, whose lineages diverged ∼100-150 million years ago, compared the micro- and macrostructure, material properties, and bending rigidity of their ODs, and examined the underlying bones of the skull roof and jaw (including teeth when possible). Unsurprisingly, OD shape, taken alone, impacts bending rigidity, with the ODs of Corucia zebrata being most flexible and those of Timon lepidus being most rigid. Macroscopic variation is also reflected in microstructural diversity, with differences in tissue composition and arrangement. However, the properties of the core bony tissues, in both ODs and cranial bones, were found to be similar across taxa, although the hard, capping tissue on the ODs of Heloderma and Pseudopus had material properties similar to those of tooth enamel. The results offer evidence on the functional adaptations of cranial ODs, but questions remain regarding the factors driving their diversity. STATEMENT OF SIGNIFICANCE: Understanding nature has always been a significant source of inspiration for various areas of the physical and biological sciences. Here we unravelled a novel biomineralization, i.e. calcified tissue, OD, forming within the skin of lizards which show significant diversity across the group. A range of techniques were used to provide an insight into these exceptionally diverse natural structures, in an integrated, whole system fashion. Our results offer some suggestions into the functional and biomechanical adaptations of OD and their hierarchical structure. This knowledge can provide a potential source of inspiration for biomimetic and bioinspired designs, applicable to the manufacturing of light-weight, damage-tolerant and multifunctional materials for areas such as tissue engineering.

The use of optical coherence tomography for skin evaluation in healthy rats.

BACKGROUND: Noninvasive diagnostic techniques allow for morphological and morphometric in vivo evaluation of the skin. Optical coherence tomography (OCT) is a method that allows visualization of dermal structures up to several 100 µm with a resolution of 3-7.5 µm. OBJECTIVES: The aim of the study was the morphological and morphometric assessment of rats' skin using SD-OCT. ANIMALS: Fifteen male Wistar rats, aged 3 and 8 months, weighing 350-450 g. MATERIALS AND METHODS: The skin of the plantar metatarsal area of the right pelvic limb was assessed. The measurements were performed using Spectral Domain Optical Coherence Tomography (SD-OCT) scans and histological images. RESULTS: Spectral Domain Optical Coherence Tomography could determine the boundary between the epidermis and the dermis. Apart from the stratum corneum (SC), it did not allow for the differentiation of the individual epidermal layers. In the SD-OCT and in the histological examination, the mean thicknesses of the layers (µm ± SD) were (respectively): SC 33.053 ± µm(SD 5.85, 29.675 ± 5.54; epidermis 88.2 ± 7.97, 65.126 ± 13.23; dermis 259.86 ± 18.29, 166.05 ± 31.88 µm. There was a correlation between the total epidermal SD-OCT and histological measurements (r = 0.43, p = 0.05). Bland-Altman plots revealed a bias of -19.18 (95% confidence interval) -39.21 to 0.84 µm) in the case of live epidermis (stratum granulosum, stratum spinous, stratum basale). CONCLUSIONS AND CLINICAL RELEVANCE: Spectral Domain Optical Coherence Tomography can be used to evaluate rat epidermis and dermis. The method enables the differentiation of the SC, as well as the epidermis and the dermis. SD-OCT and histological thickness dimensions of the epidermis and skin differ.

Contexte - Les techniques de diagnostic non invasives permettent une évaluation morphologique et morphométrique in vivo de la peau. La tomographie par cohérence optique (OCT) est une méthode qui permet de visualiser les structures dermiques jusqu'à plusieurs centaines de micromètres avec une résolution de 3 à 7,5 µm. Objectifs - Le but de l'étude était l'évaluation morphologique et morphométrique de la peau des rats par SD-OCT. Animaux - Quinze rats Wistar mâles, âgés de 3 et 8 mois, pesant 350-450 g. Matériels et méthodes - La peau de la zone métatarsienne plantaire du membre pelvien droit a été évaluée. Les mesures ont été réalisées à l'aide de scaners SD-OCT (Spectral Domain Optical Coherence Tomography) et d'images histologiques Résultats - Le SD-OCT a pu déterminer la frontière entre l'épiderme et le derme. En dehors de la couche cornée (SC), il n'a pas permis la différenciation des couches épidermiques individuelles. Au SD-OCT et à l'examen histologique, les épaisseurs moyennes des couches (µm ± SD) étaient (respectivement) : SC 33,053 ± µm (SD 5,85, 29,675 ± 5,54 ; épiderme 88,2 ± 7,97, 65,126 ± 13,23 ; derme 259,86 ± 18,29, 166,05 ± 31,88 µm). Il y avait une corrélation entre le SD-OCT épidermique total et les mesures histologiques (r = 0,43, P = 0,05) Les tracés de Bland-Altman ont révélé un biais de -19,18 (intervalle de confiance à 95 %) -39,21 à 0,84 µm) dans le cas d'épiderme vivant (stratum granulosum, stratum spinous, stratum basale). Conclusions et pertinence clinique - Le SD-OCT peut être utilisé pour évaluer l'épiderme et le derme de rat. La méthode permet de différencier le SC, ainsi que l'épiderme et le derme. Le SD-OCT et les dimensions d'épaisseur histologiques de l'épiderme et de la peau diffèrent.

Introducción - las técnicas de diagnóstico no invasivas permiten la evaluación morfológica y morfométrica in vivo de la piel. La tomografía de coherencia óptica (OCT) es un método que permite la visualización de estructuras dérmicas de hasta varios cientos de micrómetros con una resolución de 3 a 7,5 µm. Objetivos - El objetivo del estudio fue la evaluación morfológica y morfométrica de la piel de ratas mediante SD-OCT. Animales - Quince ratas Wistar macho, de 3 y 8 meses de edad, con un peso de 350 a 450 g. Materiales y métodos - Se evaluó la piel de la zona metatarsiana plantar del miembro pélvico derecho. Las mediciones se realizaron utilizando escaneos SD-OCT (Tomografía de Coherencia Óptica de Dominio Espectral) e imágenes histológicas. Resultados - SD-OCT pudo determinar el límite entre la epidermis y la dermis. Aparte del estrato córneo (SC), no permitía la diferenciación de las capas epidérmicas individuales. En la SD-OCT y en el examen histológico, los espesores medios de las capas (µm ± SD) fueron (respectivamente): SC 33.053 ± µm (SD 5.85, 29.675 ± 5.54; epidermis 88.2 ± 7.97, 65.126 ± 13.23; dermis 259.86 ± 18,29, 166,05 ± 31,88 µm. Hubo una correlación entre el SD-OCT epidérmico total y las mediciones histológicas (r = 0,43, P = 0,05). Las gráficas de Bland-Altman revelaron un sesgo de -19,18 (intervalo de confianza del 95 %) -39,21 a 0,84 µm) en el caso de epidermis viva (estrato granuloso, estrato espinoso, estrato basal). Conclusiones y relevancia clínica- SD-OCT se puede utilizar para evaluar la epidermis y la dermis de rata. El método permite diferenciar el SC, así como la epidermis y la dermis. Las dimensiones de grosor de la epidermis y la piel difieren entre SD-OCT y la histología.

Contexto - Técnicas diagnósticas não invasivas permitem a avaliação morfológica e morfométrica in vivo da pele. A tomografia de coerência óptica (OCT) é um método que possibilita a visualização de estruturas dérmicas de até centenas de micrômetros com uma resolução de 3-7,5 µm. Objetivos - O objetivo do estudo foi a avaliação morfométrica e morfológica da pele de ratos utilizando SD-OCT. Animais - Quinze ratos Wistar machos, de três a oito meses de idade, pesando de 350 a 450 g. Materiais e métodos - A pele da região metatársica plantar do membro pélvico direito foi avaliada. As mensurações foram realizadas utilizando o SD-OCT (Spectral Domain Optical Coherence Tomography) e imagens histológicas. Resultados - A SD-OCT foi capaz de determinar o limite entre derme e epiderme. A exceção do estrato córneo (SC), não foi possível a diferenciação das camadas da epiderme individualmente. Na SD-OCT e na avaliação histológica, as espessuras médias das camadas fora, (µm ± DP), respectivamente: SC 33,053 ± 5,85; 29,675 ± 5,54; epiderme 88,2 ± 7,97; 65,126 ± 13,23; derme 259,86 ± 18,29; 166,05 ± 31,88 µm. Houve correlação entre SD-OCT e avaliação histológica nas mensurações da epiderme total (r = 0,43, P = 0,05). Os gráficos de Bland-Altman revelaram um viés de -19,8% (95% de intervalo de confiança) - 39,21 a 0,84 µm) no caso da epiderme viva (estrato espinhoso, estrato granuloso e estrato basal). Conclusões e relevância clínica - SD-OCT pode ser utilizada para avaliar a derme e a epiderme de ratos. Este método permite a diferenciação do SC, bem como da derme e epiderme. Pode haver discrepância na espessura da epiderme e da pele na SD-OCT e análise histológica.

Comparative morphology of the paw pad of the main arboreal Xenarthras from Amazon.

Paw pads are specializations of the integument and important shock absorbers of the locomotor system, as well as pressure, pain, temperature, storage and excretion sensors. Aiming to describe the paw pad morphology of the main arboreal xenarthras species in the Amazon, 16 animals were studied, Bradypus variegatus (6), Choloepus didactylus (5), Tamandua tetradactyla (3) and Cyclopes didactylus (2) that after death were donated to the Animal Morphological Research Laboratory (LaPMA / Ufra). The corpses were thawed and fixed with 10% aqueous formalin solution. The paw pads were measured, photographed and removed by skin incision dorsally to them. Fragments were used for routine histological processing, using two staining techniques: Hematoxylin-Eosin (HE) and Gomori's Trichrome, in sections of 6 to 8 µm. Choloepus didactylus, Tamandua tetradactyla and Cyclopes didactylus have digital paw pads, one in each digit, and one palm, as well as a plantar, whose shapes and colours are distinct from each other. Bradypus variegatus, however, has only one palmar and one plantar pad. Histologically, they have keratinized stratified squamous epithelium, supported by a large amount of collagen fibres and fibroblast cords in the dermis and hypodermis. Groups of eccrine sweat glands were observed in the reticular dermis of C. didactylus, B. variegatus, T. tetradactyla and only in the hypodermis of Cyclopes didactylus.

One Size Does Not Fit All: Diversifying Immune Function in the Skin.

Our body's most outward facing epithelial barrier, the skin, serves as the frontline defense against myriad environmental assailants. To combat these motley threats, the skin has evolved a sophisticated immunological arsenal. In this article, I provide an overview of the skin's complex architecture and the distinct microniches in which immune cells reside and function. I review burgeoning literature on the synchronized immune, stromal, epithelial, and neuronal cell responses in healthy and inflamed skin. Next, I delve into the distinct requirement and mechanisms of long-term immune surveillance and tissue adaptation at the cutaneous frontier. Finally, by discussing the contributions of immune cells in maintaining and restoring tissue integrity, I underscore the constellation of noncanonical functions undertaken by the skin immune system. Just as our skin's immune system benefits from embracing diverse defense strategies, so, too, must we in the immunology research community support disparate perspectives and people from all walks of life.

Structural and functional differences in skin of colour.

The term 'skin of colour' (SOC), refers to individuals of African, Latinx, Asian, Native Hawaiian, Pacific Islander and Indigenous descent. These individuals typically have darker skin tones compared with white individuals and they often present with unique disorders of the skin or with common disorders that have a unique appearance. Certain skin conditions commonly associated with SOC patients, in contrast to individuals with lighter skin tones, are explained by structural and functional differences between this population and the white population. Variations in functional differences between these two groups are dependent on structural differences in melanosomes, stratum corneum, epidermis and dermis. Understanding the structural distinctions between white populations and SOC populations will provide insight into common disorders in SOC patients, including hyperpigmentation, hypopigmentation, dry skin, scaliness, xerosis, sensitive skin and keloids. Furthermore, understanding structural and functional skin difference will encourage more research regarding aetiology of disease and therapeutic interventions.

Automatic algorithm for the characterization of sweat ducts in a three-dimensional fingerprint.

In this study, an automatic algorithm has been presented based on a convolutional neural network (CNN) employing U-net. An ellipsoid and an ellipse were applied for approximation of a three-dimensional sweat duct and en face sweat pore at the different depths, respectively. The results demonstrated that the length and the diameter of the ellipsoid can be used to quantitatively describe the sweat ducts, which has a potential for estimating the frequency of resonance in millimeter (mm) wave and terahertz (THz) wave. In addition, projection-based sweat pores were extracted to overcome the effect that the diameters of en face sweat pores depend on the depth. Finally, the projection-based image of sweat pores was superposed with a maximum intensity projection (MIP)-based internal fingerprint to construct a hybrid internal fingerprint, which can be applied for identification recognition and information encryption.

Lens fluorescence and skin fluorescence in the Copenhagen Twin Cohort Eye Study: Covariates and heritability.

Lens and skin fluorescence are related to the systemic accumulation of advanced glycation end products, which is accelerated in diabetes. We have examined lens fluorescence and skin fluorescence in healthy adult twins. The study enrolled twins aged median 59 years from a national population-based registry. Diabetic individuals were excluded from analysis. The interrelatedness between fluorescence parameters and relations between fluorescence and age, current HbA1c and smoking pack years were examined using correlation tests and mixed model linear regression analyses. Broad-sense heritability was analyzed and compared for lens fluorescence, skin fluorescence and HbA1c. Lens fluorescence and skin fluorescence were crudely interrelated (R = 0.38). In linear regression analyses, age explained a larger fraction of the variance in lens fluorescence (R2 = 32%) than in skin fluorescence (R2 = 20%), whereas HbA1c explained smaller variance fractions (R2 = 3% and 8%, respectively) followed by smoking pack years (4% and 3%, respectively). In multivariate analyses, age, HbA1c and smoking pack years combined explained more of the variance in lens fluorescence (R2 = 35%) than in skin fluorescence (R2 = 21%), but the influence of HbA1c on lens fluorescence was not statistically significant (p = .2). Age-adjusted broad-sense heritability was 85% for lens fluorescence, 53% for skin fluorescence and 71% for HbA1c in best fitting heritability models. Both fluorescence parameters increased with age, current glycemia and cumulative smoking. Lens fluorescence was found to be a predominantly heritable trait, whereas skin fluorescence was more influenced by environmental factors and closer related to current glycemia. The results suggest that skin fluorophores have a faster turn-over than lens fluorophores.

Developmental genetics of color pattern establishment in cats.

Intricate color patterns are a defining aspect of morphological diversity in the Felidae. We applied morphological and single-cell gene expression analysis to fetal skin of domestic cats to identify when, where, and how, during fetal development, felid color patterns are established. Early in development, we identify stripe-like alterations in epidermal thickness preceded by a gene expression pre-pattern. The secreted Wnt inhibitor encoded by Dickkopf 4 plays a central role in this process, and is mutated in cats with the Ticked pattern type. Our results bring molecular understanding to how the leopard got its spots, suggest that similar mechanisms underlie periodic color pattern and periodic hair follicle spacing, and identify targets for diverse pattern variation in other mammals.

Distribution, fine structure, and three-dimensional innervation of lamellar corpuscles in rat plantar skin.

Lamellar corpuscles function as mechanoreceptors in the skin, composed of axon terminals and lamellae constructed by terminal Schwann cells. They are classified into Pacinian, Meissner, and simple corpuscles based on histological criteria. Lamellar corpuscles in rat dermal papilla cells have been reported; however, the morphological aspects have yet to be thoroughly investigated. In the present study, we analyzed the enzyme activity, distribution, fine structure, and three-dimensional innervation of lamellar corpuscles in rat plantar skin. The lamellar corpuscles exhibiting non-specific cholinesterase were densely distributed in rat footpads, evident as notable skin elevations, especially at the apex, the highest portion of the ridges in each footpad. In contrast, only a few lamellar corpuscles were found in other plantar skin areas. Lamellar corpuscle was considered composed of a flat axon terminal Schwann cell lamellae, which were roughly concentrically arranged in the dermal papilla. These histological characteristics correspond to those of the simple corpuscle. Moreover, the axon tracing method revealed that one trunk axon innervated several simple corpuscles. The territory of the trunk axons overlapped with each other. Finally, the animals' footprints were analyzed. During the pausing and walking phases, footpads are often in contact with the floor. These results demonstrate that the type of lamellar corpuscles in the dermal papillae of rat plantar skin is a simple corpuscle and implies that their distribution pattern in the plantar skin is convenient for efficient sensing and transmission of mechanical stimuli from the ground.

Regulatory mechanism of oral mucosal rete peg formation.

Rete pegs are finger-like structures that are formed during the development and wound healing process of the skin and oral mucosa, and they provide better mechanical resistance and nutritional supply between the epithelium and dermis. An increasing number of studies have shown that rete pegs have physiological functions, such as resisting bacterial invasion, body fluid loss, and other harmful changes, which indicate that rete pegs are important structures in natural skin and oral mucosa. Although a great deal of progress has been made in scaffold materials and construction methods for tissue-engineered skin and oral mucosa in recent years, construction of the oral mucosa with functional rete pegs remains a major challenge. In this review, we summarized current research on the progress on formation of rete pegs in human oral mucosa as well as its molecular basis and regulatory mechanism, which might provide new ideas for functional construction of tissue-engineered skin and oral mucosa.

Defining Skin Quality: Clinical Relevance, Terminology, and Assessment.

BACKGROUND: Flawless skin is one of the most universally desired features, and demand for improvements in skin quality is growing rapidly. Skin quality has been shown to substantially impact emotional health, quality of life, self-perception, and interactions with others. Although skin quality improvements are a common end point in studies of cosmeceuticals, they are rarely assessed in clinical studies of other aesthetic treatments and products. Descriptive terminology for skin quality parameters also varies considerably within the aesthetic field, relying on a range of redundant and occasionally contradictory descriptors. In short, skin quality has not been clearly defined. OBJECTIVE: The goal of this review is to highlight the importance of skin quality to patients and physicians, explore known and unknown factors comprising skin quality, and provide clarity regarding terminology, descriptors, and evaluation tools for assessing skin quality. MATERIALS AND METHODS: A review of the literature on skin quality was performed without limitation on publication date. Relevant articles are presented. RESULTS AND CONCLUSION: We propose a framework of attributes contributing to skin quality rooted in 3 fundamental categories-visible, mechanical, and topographical-with the aim to provide information to help guide clinicians and inform future clinical studies.

Testicular shape, scrotal skin thickness and testicular artery blood flow changes in bulls of different ages.

The aim of this study was to compare the biometric testicular characteristics, skin thickness and haemodynamics of the testicular artery of 12- and 24-month-old bulls using Doppler ultrasonography, the study was conducted using 48 indicus-taurus animals. The scrotal circumference (SC) and biometry characteristics of the bulls were measured to calculate the testicular volume. Doppler ultrasonography was used to obtain the haemodynamic values of the testicular artery. The skin thickness and volume were lower (p<.01) in the younger bulls (12 months:4.68 ± 0.68 mm; 168.76 ± 47.96 cm3 ) versus 24 months (5.05 ± 0.89; 499.73 ± 129.24 cm3 ) animals (p<.01). During diastole, mean velocity was lower in the 12 months (7.98 ± 3.83) than in the 24 months (11.37 ± 4.15) animals (p <.05). The 12-month-old animals had higher pulsatility and resistivity indices (0.49 ± 0.02; 0.51 ± 0.20) compared to the 24-month-old animals (0.32 ± 0.16; 0.40 ± 0.15) (p < .05). The final testicular end velocity was lower in animals with long/moderate-shaped (L/M) (7.31 ± 2.91) than in those moderate/oval-shaped (M/O) (11.48 ± 3.88) testicles (p < .05). Animals with L/M testes presented higher pulsatility values and resistivity indices (0.51 ± 0.05; 0.55 ± 0.04) compared to animals with M/O shape (0.29 ± 0.20; 0.36 ± 0.15). We showed that the blood flow of the supra testicular artery between the two evaluated ages differed, and that 24-month-old bulls presented better thermoregulation capacity. Animals with a long/moderate testicular format presented a greater vascular resistance, which was imposed on the blood flow due to the anatomical differences in the testicular artery, resulting in lower velocity, and indicating better heat dissipation in this format.

Genomic and anatomical comparisons of skin support independent adaptation to life in water by cetaceans and hippos.

The macroevolutionary transition from terra firma to obligatory inhabitance of the marine hydrosphere has occurred twice in the history of Mammalia: Cetacea and Sirenia. In the case of Cetacea (whales, dolphins, and porpoises), molecular phylogenies provide unambiguous evidence that fully aquatic cetaceans and semiaquatic hippopotamids (hippos) are each other's closest living relatives. Ancestral reconstructions suggest that some adaptations to the aquatic realm evolved in the common ancestor of Cetancodonta (Cetacea + Hippopotamidae). An alternative hypothesis is that these adaptations evolved independently in cetaceans and hippos. Here, we focus on the integumentary system and evaluate these hypotheses by integrating new histological data for cetaceans and hippos, the first genome-scale data for pygmy hippopotamus, and comprehensive genomic screens and molecular evolutionary analyses for protein-coding genes that have been inactivated in hippos and cetaceans. We identified eight skin-related genes that are inactivated in both cetaceans and hippos, including genes that are related to sebaceous glands, hair follicles, and epidermal differentiation. However, none of these genes exhibit inactivating mutations that are shared by cetaceans and hippos. Mean dates for the inactivation of skin genes in these two clades serve as proxies for phenotypic changes and suggest that hair reduction/loss, the loss of sebaceous glands, and changes to the keratinization program occurred ∼16 Ma earlier in cetaceans (∼46.5 Ma) than in hippos (∼30.5 Ma). These results, together with histological differences in the integument and prior analyses of oxygen isotopes from stem hippopotamids ("anthracotheres"), support the hypothesis that aquatic skin adaptations evolved independently in hippos and cetaceans.