Dermis

The OECD guideline for studies on percutaneous penetration to be used in hazard and risk evaluations prescribes experimental conditions with optimal barrier integrity of the skin, which in many occupational settings probably is not true. Thus, workers may have compromised skin due to chemical or mechanical damage, due to different medical conditions (eczema, dermatitis, skin irritation) or related to occupational scenarios involving prolonged wet work. The present study used the OECD guideline procedures to study the in vitro percutaneous penetration through human skin of a number of model substances (glyphosat, caffeine, benzoic acid, malathion) covering a range of solubilities. Further, we studied the extent to which a slightly damaged skin would change the rate, the amount absorbed during dermal exposure and the distribution of chemical deposition between epidermis and dermis. The present study demonstrates that a limited damage to the skin significantly increases the permeability coefficient (K p) as well as total percutaneous penetration of chemicals, and most significantly for those compounds that due to their physicochemical characteristics (the most hydrophilic as well as the most lipophilic) have low penetration rates through intact skin. The present experiment not only confirms the proportionality between lipophilicity and potential for percutaneous penetration, but also illustrates that at a certain degree of lipophilicity of a model compound, the different skin compartments become more attractive for temporary deposition of model compounds. Moreover, a clear change from epidermal deposition towards a dominating dermis deposition of chemicals temporarily deposited within the skin is seen following damage to the skin barrier. Thus, the distribution of chemicals within the skin compartments is affected by the physicochemical characteristics of the chemicals as well as by the integrity of the skin. This observation may have implications when evaluating the possibility of removing chemicals from the skin through different cleansing procedures following unintended dermal exposures.

Recent data, using a murine model, have indicated that dermal exposure to perfluorooctanoic acid (PFOA) induces immune modulation, suggesting that this may be an important route of PFOA exposure. To investigate the dermal penetration potential of PFOA, serum concentrations were analyzed in mice following topical application. Statistically significant and dose-responsive increases in serum PFOA concentrations were identified. In vitro dermal penetration studies also demonstrated that PFOA permeates both mouse and human skin. Investigation into the mechanisms mediating PFOA penetration demonstrated that dermal absorption was strongly dependent upon the ionization status of PFOA. In addition, PFOA solid, but not 1% PFOA/acetone solution, was identified as corrosive using a cultured epidermis in vitro model. Despite its corrosive potential, expression of inflammatory cytokines in the skin of topically exposed mice was not altered. These data suggest that PFOA is dermally absorbed and that under certain conditions the skin may be a significant route of exposure.

Background  Although low dehydroepiandrosterone (DHEA) is suspected to have a role in skin ageing, little information is available on the mechanisms potentially involved.Objectives  To obtain information on androgen receptor (AR) and procollagen expression in ageing skin during DHEA treatment.Methods  A placebo-controlled, randomized, prospective study was performed with 75 postmenopausal women aged 60–65 years. The women were treated twice daily for 13 weeks with 3·0 mL of placebo or 0·1%, 0·3%, 1% or 2% DHEA cream applied on the face, arms, back of hands, upper chest and right thigh where 2-mm biopsies were collected before and after treatment.Results  Although the overall structure of the epidermis was not significantly affected at the light microscopy level, AR expression examined by immunocytochemistry was markedly increased by DHEA treatment. In the dermis, the expression levels of procollagen 1 and 3 mRNA estimated by in situ hybridization were increased by DHEA treatment. In addition, the expression of heat shock protein (HSP) 47, a molecule believed to have chaperone-like functions potentially affecting procollagen biosynthesis, was also found by immunocytochemistry evaluation to be increased, especially at the two highest DHEA doses.Conclusion  These data suggest the possibility that topical DHEA could be used as an efficient and physiological antiageing skin agent.

Background  Lipoedema is an accumulation of fat abnormally distributed in the lower limbs, and lymphoedema is oedema caused by a deficiency of the lymphatic system. High-resolution ultrasound operating at 20 MHz makes it possible to characterize dermal oedema.Objectives  The purpose of our study was to demonstrate that high-resolution ultrasound imaging of the skin can differentiate lipoedema from lymphoedema.Methods  Sixteen patients with lymphoedema (22 legs), eight patients with lipoedema (16 legs) and eight controls (16 legs) were included. Patients with lipolymphoedema were excluded. Ultrasound examinations were carried out with a real-time high-resolution ultrasound device on three different sites for each lower limb. The images were then anonymized and examined by an independent dermatologist who was blind to the clinical diagnosis. A new series of images was examined by three dermatologists to check interobserver agreement.Results  A significant difference in dermal thickness was observed between patients with lymphoedema and those with lipoedema and between patients with lymphoedema and controls. No significant difference in dermal thickness was shown between patients with lipoedema and controls at the thigh or ankle. Dermal hypo-echogenicity was found in at least one of the three sites in 100% of patients with lymphoedema, 12·5% of cases with lipoedema and 6·25% of the controls. Hypoechogenicity affected the entire dermis in all cases of lymphoedema except one. In cases of lipoedema and controls, hypoechogenicity was localized at the ankle and prevailed in the upper dermis. The expert correctly diagnosed all lower limbs with lymphoedema. No cases of lipoedema were diagnosed as lymphoedema. Exact interobserver agreement was excellent (0·98).Conclusions  High-resolution cutaneous ultrasonography makes it possible to differentiate lymphoedema from lipoedema. Obtaining a reliable diagnosis through high-resolution cutaneous ultrasonography might be valuable for improving the treatment of lipoedema and lymphoedema.

This study proposes a new method to determine the mechanical properties of human skin by the use of the indentation test [Pailler-Mattei, 2004. Caractérisation mécanique et tribologique de la peau humaine in vivo, Ph.D. Thesis, ECL-no. 2004-31; Pailler-Mattei, Zahouani, 2004. Journal of Adhesion Science and Technology 18, 1739-1758]. The principle of the measurements consists in applying an in vivo compressive stress [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222; Bosboom et al., 2001. Journal of Biomechanics 34, 1365-1368; Oomens et al., 1984. Selected Proceedings of Meetings of European Society of Biomechanics, pp. 227-232; Oomens et al., 1987. Journal of Biomechanics 20(9), 877-885] on the skin tissue of an individual's forearm. These measurements show an increase in the normal contact force as a function of the indentation depth. The interpretation of such results usually requires a long and tedious phenomenological study. We propose a new method to determine the mechanical parameters which control the response of skin tissue. This method is threefold: experimental, numerical, and comparative. It consists combining experimental results with a numerical finite elements model in order to find out the required parameters. This process uses a scheme of extended Kalman filters (EKF) [Gu et al., 2003. Materials Science and Engineering A345, 223-233; Nakamura et al., 2000. Acta Mater 48, 4293-4306; Leustean and Rosu, 2003. Certifying Kalman filters. RIACS Technical Report 03.02, 27pp. http://gureni.cs.uiuc.edu/~grosu/download/luta + leo.pdf; Welch and Bishop, An introduction to Kalman filter, University of North Carolina at Chapel Hill, 16p. http://www.cs.unc.edu/~welch/kalman/]. The first results presented in this study correspond to a simplified numerical modeling of the global system. The skin is assumed to be a semi-infinite layer with an isotropic linear elastic mechanical behavior [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222] This analysis will be extended to more realistic models in further works.

Abstract:  Destruction of collagen is a hallmark of photoaging. The major enzyme responsible for collagen 1 digestion, matrix metalloproteinase-1 (MMP-1), is induced by exposure to sunlight. To study the molecular trigger for this induction, human skin was ultraviolet-B (UVB)-irradiated and treated with liposome-encapsulated DNA repair enzymes. The photolyase-mediated DNA repair of epidermal UV damage was associated with a reduction of MMP-1 mRNA and protein expression in both the epidermal and dermal compartments of the skin. The role of the epidermal cells in MMP-1 induction in the fibroblasts was examined when human epidermal keratinocytes were irradiated with UVB and their media were transferred to unirradiated human dermal fibroblasts. Transfer of media from irradiated keratinocytes to unirradiated fibroblasts enhanced MMP-1 mRNA and protein. Thus, UV damage to keratinocytes of the epidermis may participate in the destruction of collagen in the dermis by release of soluble mediators that signal fibroblasts to release MMP-1. The MMP-1 induction was reduced when the keratinocytes were treated with DNA repair enzymes T4 endonuclease V or UV endonuclease prior to transfer of the media to fibroblasts. This implies that UVB, which deposits most of its energy on the chromatin of the epidermal keratinocytes and to a lesser extent in the upper dermis, has a significant role in photoaging. DNA damage in the keratinocytes initiates one of the signals for MMP-1 release, and enhancing DNA repair can reduce MMP-1 expression in human skin cells and tissue.

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. To study the immunohistochemical properties of normal porcine skin in comparison with human skin. 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. 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 un...

Jaringan Hewan adalah sekumpulan sel yang sama, memiliki fungsi yang sama membentuk sebuah jaringan organ hewan. Bukan hanya satu sel tetapi beberapa sel yang sama dalam hal ini memiliki fungsi yang sama pada suatu organ tertentu pada hewan.

SISTEM INTEGUMEN
Sistem integumen adalah sistem organ yang membedakan, memisahkan, melindungi, dan menginformasikan hewan terhadap lingkungan sekitarnya. Sistem ini seringkali merupakan bagian sistem organ yang terbesar yang mencakup kulit, rambut, bulu, sisik, kuku, kelenjar keringat dan produknya (keringat atau lendir). Kata ini berasal dari bahasa Latin "integumentum", yang berarti "penutup".

Anetoderma, is characterized by herniated atrophic macules clinically and by decreased to absent dermal elastic fibers histopathologically. Atrophoderma is characterized by depressed, atrophic, pigmented patches clinically and by thickened and homogenized dermal collagen bundles with absence of elastolysis histopathologically. Atrophoderma elastolyticum discretum describes lesions that are reminiscent of atrophoderma clinically but they are compatible with anetoderma histopathologically. A 34-year-old female patient presented with diffuse, hypopigmented, atrophic, shiny macules on the upper limbs and upper trunk. Histopathological examination revealed an atrophic epidermis with disorganized, hyalinized and coarse collagen bundles in the middle and lower dermis. Elastic fiber loss and fragmentation were detected in the upper dermis. The other patient was a 42-year-old female patient. She applied with diffuse, hypopigmented, shiny, atrophic macules on the upper limbs and upper trunk. Histopathological examination revealed findings that were similar to those of the first case but there was near complete loss of elastic fibers throughout the whole thickness of dermis. Our cases did not show depressed or herniated atrophic macules clinically but the macules were at the same level with the surrounding healthy skin. Histopathological findings in these cases showed the histopathological features of both atrophoderma and anetoderma. These two cases are interesting because they may represent a clinicopathological entity which has not been described before.

It has been known for over 20 years that foetal calf serum can induce hypertrophy in cultured cardiomyocytes but this is rarely considered when examining cardiomyocytes derived from pluripotent stem cells (PSC). Here, we determined how serum affected cardiomyocytes from human embryonic- (hESC) and induced pluripotent stem cells (hiPSC) and hiPSC from patients with hypertrophic cardiomyopathy linked to a mutation in the MYBPC3 gene. We first confirmed previously published hypertrophic effects of serum on cultured neonatal rat cardiomyocytes demonstrated as increased cell surface area and beating frequency. We then found that serum increased the cell surface area of hESC- and hiPSC-derived cardiomyocytes and their spontaneous contraction rate. Phenylephrine, which normally induces cardiac hypertrophy, had no additional effects under serum conditions. Likewise, hiPSC-derived cardiomyocytes from three MYBPC3 patients which had a greater surface area than controls in the absence of serum...

This study was undertaken to examine the role fibroblasts play in the formation of the basement membrane (BM) in human skin equivalents. For this purpose, keratinocytes were seeded on top of fibroblast-free or fibroblast-populated collagen matrix or de-epidermized dermis and cultured in the absence of serum and exogenous growth factors. The expression of various BM components was analyzed on the

To introduce the adhesion site of proteins and/or cells on parylene C (PC)-coated medical devices that can be used as implantable biosensors or drug delivery capsules, the PC surfaces were initially modified by the Friedel–Crafts acylation reaction to generate active chlorines. These chlorines were then employed to initiate the atom transfer radical polymerization of tert-butyl acrylate (TBA) and form a polymer brush layer of polyTBA on PC; the acrylate groups in the polymer brushes were hydrolyzed to carboxylic acid groups and further activated into succinimidyl ester groups via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide coupling reaction. The PC surface grafted with polymer brushes and activated by succinimide showed efficient attachment of proteins, including gelatin, contortrostatin (CN) and bovine serum albumin (BSA), all at high density on the PC surface. The CN density on the surface was evaluated for both monolayer and polymer brush-based coatings. Based on fluorescence measurements, the polymer brush gives a 60-fold higher surface protein density than the monolayer-based system. Gelatin was used as a model protein and covalently coated onto the modified PC surface for cell culture study. Substrates with gelatin coating showed a significantly higher cell attachment and proliferation in 7 days cultures as compared to the uncoated substrates. In addition, a conventional photolithography technique was coupled with the surface chemistry to successfully pattern the BSA labeled with fluorescein isothiocyanate on the modified PC surfaces.► Parylene C (PC) was surface modified by chemical reactions to immobilize the functional polymer brushes or monolayer groups for protein immobilization. ► The polymer brushes based PC surface exhibited the significantly higher amount of protein attachment than that of the monolayer based PC surface. ► Polymer brushes based PC was coated with gelatin, and cell showed higher attachment and proliferation than that on monolayer based PC. ► Photolithography technique was applied to pattern the protein onto modified PC.

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. To study the immunohistochemical properties of normal porcine skin in comparison with human skin. 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. 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 un...