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Murine Skin (murine + skin)
Selected AbstractsUVAI-induced Edema and Pyrimidine Dimers in Murine Skin,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2000Ronald D. Ley ABSTRACT The induction of edema and pyrimidine dimers in epidermal DNA was determined in the skin of SKH:HR1 mice exposed to graded doses of ultraviolet radiation AI (UVAI; 340,400 nm). Exposure to UVAI induced 1.6 ± 0.08 × 10,6 (mean ± standard error of mean) pyrimidine dimers per 108 Da of DNA per J/m2. Edema in irradiated animals was determined as an increase in skinfold thickness. A dose of 1.8 × 106 J/m2 of UVAI that resulted in a 50% increase in skinfold thickness (SFT50%) would have induced 1.0 × 105 dimers per basal cell genome. A similar increase in SFT induced by full spectrum solar ultraviolet radiation (290,400 nm) would accompany the induction of 11.0 × 105 pyrimidine dimers per basal cell genome. These results support a hypothesis that UVAI-induced pathological changes of the skin are mediated through the formation of nondimer photoproducts. [source] In vivo experimental model of human gingival mucosa using immunodeficient miceJOURNAL OF PERIODONTAL RESEARCH, Issue 4 2007K. Tsukinoki Background and Objective:, To establish an in vivo experimental model for examining human periodontal tissue, the present study examined several transplant techniques that maintain the structure and characteristics of human gingival mucosa. Material and Methods:, Human oral mucosal tissue samples were collected from the gingiva (n = 11), palate (n = 1), and tongue (n = 3). These mucosal grafts were transplanted onto BALB/c nu/scid mice with double-mutant immunodeficiency. Murine skin, twice the size of the graft, was cut open in an ,,'-shape. Next, the connective tissue side of the graft was placed onto the murine connective tissue. Immunohistochemical analysis was also performed, using polyclonal rabbit antibody to involucrin, monoclonal antibody to vimentin, monoclonal antibody to CD34, and monoclonal antibody to Ki-67, to determine whether the characteristics of human oral mucosa were maintained. Results:, When the connective tissue side of the graft was placed on the murine fascial membrane, the histological structure of the graft was maintained for 60 d. These grafts were examined for human characteristics using human-specific antibodies. Immunohistochemically, the expression patterns of involucrin, vimentin, and Ki-67 indicated that transplanted mucosa revealed normal human characteristics, including differentiation and proliferation up to 80 d. CD34 was not detected in the graft endothelial cells. Conclusion:, The present study revealed that the novel technique of transplantation of human gingival mucosa in nu/scid mice may serve as an in vivo experimental model of periodontal disease. [source] Topical treatment with thiazolidinediones, activators of peroxisome proliferator-activated receptor-,, normalizes epidermal homeostasis in a murine hyperproliferative disease modelEXPERIMENTAL DERMATOLOGY, Issue 3 2006Marianne Demerjian Abstract:, In a murine model of epidermal hyperplasia reproducing some of the abnormalities of several common skin disorders, we previously demonstrated the antiproliferative and pro-differentiating effects of peroxisome proliferator-activated receptor (PPAR),, PPAR,/,, and liver X receptor activators. Unlike other subgroups of PPAR activators, thiazolidinediones (TZDs), a family of PPAR, ligands, did not inhibit keratinocyte proliferation in normal murine skin. Here, we studied the effects of two TZDs, namely ciglitazone (10 mM) and troglitazone (1 mM), in the same murine model where epidermal hyperproliferation was reproduced by repeated barrier abrogation with tape stripping. Topical treatment with ciglitazone and troglitazone resulted in a marked and significant decrease in epidermal thickness. Furthermore, in all TZD-treated groups, we observed a significant decrease in keratinocyte proliferation using proliferating cell nuclear antigen, 5-bromo-2,-deoxyuridine, and tritiated thymidine incorporation. However, using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, we found no difference in apoptosis between different treatments, emphasizing that it is the antiproliferative role of these activators that accounts for the decrease of epidermal thickness. Finally, using immunohistochemical methods, we determined the effects of ciglitazone on keratinocyte differentiation in this hyperproliferative model. We observed an increased expression of involucrin and filaggrin following ciglitazone treatment, suggesting a pro-differentiating action of TZDs in this model. In summary, topical TZDs significantly reduce epidermal keratinocyte proliferation while promoting differentiation in a murine model of hyperproliferative epidermis. Together, these results suggest that in addition to their metabolic effects currently in use in the treatment of type 2 diabetes, topical TZDs could be considered as potential alternative therapeutic agents in hyperproliferative skin diseases such as psoriasis. [source] Comparison of histologic, biochemical, and mechanical properties of murine skin treated with the 1064-nm and 1320-nm Nd:YAG lasersEXPERIMENTAL DERMATOLOGY, Issue 12 2005Yong-Yan Dang Abstract:, The goal of this study was to compare the effects of the Q-switched 1064-nm Nd:YAG laser and the 1320-nm Nd:YAG laser non-ablative treatments on mouse skin in vivo. Skin elasticity measurements were carried out with a Reviscometer, and skin samples were taken for histological study, hydroxyproline content assay and estimation of collagen type I and III. By the second month after non-ablative treatments, the 1064-nm laser treatment resulted in an average of 25% greater improvement of skin elasticity, 6% more increase of dermal thickness, and 11% higher synthesis of hydroxyproline than the 1320-nm laser. Collagen type III increased markedly after the 1064-nm laser treatment whereas more collagen type I was elicited by the 1320-nm laser. Our results demonstrated that the 1064-nm laser was more effective than the 1320-nm Nd:YAG laser in non-ablative treatments, but the results needed to be confirmed in humans. It appeared that photo-mechanic reaction could cause more collagen type III synthesis whereas the photo-thermal effect was in favor of the formation of collagen type I. [source] Stimulation of epidermal calcium gradient loss and increase in TNF-, and IL-1, expressions by glycolic acid in murine epidermisEXPERIMENTAL DERMATOLOGY, Issue 8 2005Se Kyoo Jeong Abstract:, In a previous study, we reported that ,-hydroxy acids (AHA), such as glycolic acid and lactic acid, did not induce any significant changes in transepidermal water loss for normal murine skin. The ultrastructural observations, however, showed that the extent of lamellar body exocytosis significantly increased. Because AHA can theoretically decrease the calcium ion concentration by chelation, topical AHA may induce the loss of epidermal calcium gradient by lowering the calcium ion concentration in the granulocytes and, subsequently, induce lamellar body secretion. The aim of this study is to verify that glycolic acid could modulate the epidermal calcium gradient and increase lamellar body exocytosis. Seventy per cent of glycolic acid aqueous solution was applied to the normal skin of hairless mice and biochemical and morphological studies were performed. The loss of epidermal calcium gradient was observed in glycolic-acid-applied skin of hairless mice and subsequent barrier function recovery processes, such as an increase in lamellar body secretion, were observed. The extracellular glycolic acid was found to inhibit the change in intracellular calcium ion concentration in response to extracellular calcium ion concentration changes in the cultured mouse keratinocyte in vitro. The protein and mRNA expressions of tumour necrosis factor-, and interleukin-1, in the murine epidermis were significantly increased after glycolic acid application. An in vitro study using cultured keratinocytes suggested that glycolic acid could lower the calcium ion concentration, at least in part, through the chelating effects of the glycolic acid on the cationic ions. [source] Anti-vascular endothelial growth factor receptor-2 (Flk-1/KDR) antibody suppresses contact hypersensitivityEXPERIMENTAL DERMATOLOGY, Issue 11 2004Hideaki Watanabe Abstract:, The angiogenic mediator vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) have been studied extensively in neoplastic disease and some inflammatory conditions. Contact hypersensitivity (CHS) is a prototypic Langerhans' cell-dependent, T-helper (Th) 1 cell-mediated inflammatory skin disease that is now also thought to involve angiogenic mediators. The purpose of our study was to examine the role of angiogenesis and VEGF in CHS. We demonstrated that VEGF production is up-regulated in murine skin after challenge with dinitrofluorobenzene. Administration of a monoclonal antibody directed against the VEGFR-2 (DC101) resulted in a 28.8% decrease in CHS response (P < 0.001). Examination of the DC101-treated mouse skin 24 h after challenge revealed decreases in dermal inflammatory cellular infiltrates and total vessel area. Furthermore, mRNA and protein of the Th1-type cytokine interferon (IFN)-, was significantly down-regulated in skin of DC101-treated animals 24 h after challenge. The results of the study demonstrate that VEGFR-2 blockade significantly reduces vascular enlargement and edema formation and effects IFN-, expression in the skin during challenge in CHS. Our findings suggest that DC101 could function by reducing inflammatory cell migration and hence IFN-, expression during the CHS response. [source] Anti-inflammatory effects in the skin of thymosin-,4 splice-variantsIMMUNOLOGY, Issue 1 2003Michael Girardi Summary The intraepithelial lymphocyte (IEL) network of T-cell receptor ,,+ (V,5+) dendritic epidermal T cells (DETC) in murine skin down-regulates cutaneous inflammation, although the mechanism is unknown. Thymosin-,4 (T,4), identified by serial analysis of gene expression as a predominant transcript in gut IEL, encodes both a ubiquitous actin-binding protein (UT,4) with demonstrated capacity to inhibit neutrophilic infiltration, and a splice-variant limited to lymphoid tissue (LT,4) with unknown bioactivity. Freshly isolated V,5+ DETCs expressed both forms, while only LT,4 was preferentially up-regulated after cellular activation in vitro. To compare the anti-inflammatory properties of LT,4 and UT,4 in the skin in vivo, the biological activities of synthesized polypeptides were assessed using three different strategies: neutrophil infiltration by footpad ,-carrageenan injection; irritant contact dermatitis to 12-O-tetradecanoylphorbol 13-acetate; and allergic contact dermatitis to 2,4-dinitrofluorobenzene. These studies clearly showed that the anti-inflammatory activities of LT,4 were broader and most often stronger than those of UT,4. Thus, the activation-responsive expression of the lymph-specific form of T,4 may be one mechanism by which DETC, and possibly other IELs, down-regulate local inflammation. [source] Major histocompatibility complex class II, fetal skin dendritic cells are potent accessory cells of polyclonal T-cell responsesIMMUNOLOGY, Issue 2 2000A. Elbe-Bürger Summary Whereas dendritic cells (DC) and Langerhans cells (LC) isolated from organs of adult individuals express surface major histocompatibility complex (MHC) class II antigens, DC lines generated from fetal murine skin, while capable of activating naive, allogeneic CD8+ T cells in a MHC class I-restricted fashion, do not exhibit anti-MHC class II surface reactivity and fail to stimulate the proliferation of naive, allogeneic CD4+ T cells. To test whether the CD45+ MHC class I+ CD80+ DC line 80/1 expresses incompetent, or fails to transcribe, MHC class II molecules, we performed biochemical and molecular studies using Western blot and polymerase chain reaction analysis. We found that 80/1 DC express MHC class II molecules neither at the protein nor at the transcriptional level. Ultrastructural examination of these cells revealed the presence of a LC-like morphology with indented nuclei, active cytoplasm, intermediate filaments and dendritic processes. In contrast to adult LC, no LC-specific cytoplasmic organelles (Birbeck granules) were present. Functionally, 80/1 DC in the presence, but not in the absence, of concanavalin A and anti-T-cell receptor monoclonal antibodies stimulated a vigorous proliferative response of naive CD4+ and CD8+ T cells. Furthermore, we found that the anti-CD3-induced stimulation of naive CD4+ and CD8+ T cells was critically dependent on the expression of Fc,R on 80/1 DC and that the requirement for co-stimulation depends on the intensity of T-cell receptor signalling. [source] Aminolevulinic acid-loaded Witepsol microparticles manufactured using a spray congealing procedure: implications for topical photodynamic therapyJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2009Rasil Al-Kassas Abstract Objectives The aim was to enhance aminolevulinic acid (ALA) stability by incorporation into low-melting microparticles prepared using a spray congealing procedure and to evaluate temperature-triggered release, allowing topical bioavailability following melting at skin temperature. Methods ALA-loaded Witepsol microparticles were prepared using a novel spray congealing technique. Entrapment efficiency was compared with conventional emulsion-based methods and modelled drug release profiles determined using a membrane separation technique. Raised receiver medium temperature was used to determine triggered release. Bioavailability and lipid-mediated enhancement of ALA penetration were determined in excised murine skin. Key findings ALA-loaded Witepsol microparticles were spherical, with a mean diameter of 20 ,m. Loading and stability studies demonstrated effective encapsulation, ranging from 91% to 100%, with no evidence of degradation to pyrazine derivatives. ALA release correlated with dissolution medium temperature, triggered at temperatures close to that of skin. Results suggested that molten Witepsol enhanced cutaneous permeation, whereas incorporation of microparticles in a semi-solid vehicle attenuated ALA penetration. Optimal use was direct application under occlusion. Conclusions Spray congealing is superior to the emulsion-based procedures with respect to encapsulation efficiency of ALA in Witepsol matrices, providing temperature-triggered release, enhanced stability and improved penetration of ALA through keratinised skin. These features could improve ALA delivery to superficial lesions as part of photodynamic therapy. [source] Cyclooxygenase-2 Expression in Murine and Human Nonmelanoma Skin Cancers: Implications for Therapeutic Approaches,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2002Kathy P. An ABSTRACT Inflammatory stimuli result in the production of cutaneous eicosanoids, which are known to contribute to the process of tumor promotion. Cyclooxygenase (COX), the rate-limiting enzyme for the production of prostaglandins (PG) from arachidonic acid, exists in at least two isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and plays various physiological roles, whereas increased COX-2 expression is known to occur in several types of epithelial neoplasms. Enhanced PG synthesis is a potential contributing factor in UVB-induced nonmelanoma skin cancers (NMSC). Increased COX-2 staining occurs in murine skin neoplasms after chronic exposure to carcinogenic doses of UVB. In this study, immunohistochemical and Western blot analyses were employed to assess longitudinally COX-2 expression in a standard mouse UVB complete carcinogenesis protocol and in human basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). During UVB irradiation of mice, COX-2 expression consistently increased in the hyperplastic skin, the benign papillomas and the SCC. COX-2 expression was also increased in human actinic keratoses, SCC and BCC as well as in murine SCC and BCC. The pattern of COX-2 expression was quite variable, occurring in a patchy distribution in some lesions with staining confined mainly to suprabasal cell layers. In general, COX-2 expression progressively became more extensive in benign papillomas and well-differentiated murine SCC. The staining was predominantly cytoplasmic and perinuclear in some focal areas in tissue stroma around both murine and human tumors. Western blot analysis confirmed negative COX-2 expression in normal skin, whereas acute UVB exposure resulted in increased enzyme expression, which continued to increase in developing papillomas and SCC. Because of the evidence indicating a pathogenic role for eicosanoids in murine and human skin neoplasms, we performed studies to assess the anti-inflammatory and anticarcinogenic effects of green tea extracts, which are potent antioxidants. Acute exposure of the human skin to UVB (minimum erythema dose × 4) caused a transient enhancement of the COX-2 expression, which reverted to baseline within hours; however, in murine skin the expression persisted for several days. Pretreatment with the topically applied green tea extract (1 mg/cm2) largely abrogated the acute COX-2 response to UVB in mice or humans. In summary, enhanced COX-2 expression serves as a marker of epidermal UVB exposure for murine and human NMSC. These results suggest that COX-2 inhibitors could have potent anticarcinogenic effects in UVB-induced skin cancer. [source] Reflection and penetration depth of millimeter waves in murine skinBIOELECTROMAGNETICS, Issue 5 2008S.I. Alekseev Abstract Millimeter (mm) wave reflectivity was used to determine murine skin permittivity. Reflection was measured in anesthetized Swiss Webster and SKH1-hairless mice in the 37,74 GHz frequency range. Two skin models were tested. Model 1 was a single homogeneous skin layer. Model 2 included four skin layers: (1) the stratum corneum, (2) the viable epidermis plus dermis, (3) fat layer, and (4) muscle which had infinite thickness. We accepted that the permittivity of skin in the mm wave frequency range results from the permittivity of cutaneous free water which is described by the Debye equation. Using Fresnel equations for reflection we determined the skin parameters best fitting to the reflection data and derived the permittivity of skin layers. The permittivity data were further used to calculate the power density and specific absorption rate profiles, and the penetration depth of mm waves in the skin. In both murine models, mm waves penetrate deep enough into tissue to reach muscle. In human skin, mm waves are mostly absorbed within the skin. Therefore, when extrapolating the effects of mm waves found in animals to humans, it is important to take into account the possible involvement of muscle in animal effects. Bioelectromagnetics 29:340,344, 2008. © 2008 Wiley-Liss, Inc. [source] Plasma facilitated delivery of DNA to skinBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Richard J. Connolly Abstract Non-viral delivery of cell-impermeant drugs and DNA in vivo has traditionally relied upon either chemical or physical stress applied directly to target tissues. Physical methods typically use contact between an applicator, or electrode, and the target tissue and may involve patient discomfort. To overcome contact-dependent limitations of such delivery methodologies, an atmospheric helium plasma source was developed to deposit plasma products onto localized treatment sites. Experiments performed in murine skin showed that samples injected with plasmid DNA encoding luciferase and treated with plasma demonstrated increased levels of expression relative to skin samples that received injections of DNA alone. Increased response relative to injection alone was observed when either positive or negative voltage was used to generate the helium plasma. Quantitative results over a 26-day follow-up period showed that luciferase levels as high as 19-fold greater than the levels obtained by DNA injection alone could be achieved. These findings indicate that plasmas may compete with other physical delivery methodologies when skin is the target tissue. Biotechnol. Bioeng. 2009; 104: 1034,1040. © 2009 Wiley Periodicals, Inc. [source] Percutaneous application of peptidoglycan from Staphylococcus aureus induces an increase in mast cell numbers in the dermis of miceCLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2005K. Matsui Summary Background Atopic dermatitis (AD) is a chronic inflammatory skin disease with immunopathologic features that vary depending on the duration of the lesion. The dermis of lesional skin of AD patients shows an increased number of inflammatory cells such as mast cells, eosinophils and mononuclear cells and superficial Staphylococcus aureus colonization. Objective The purpose of this study was to determine the effects of peptidoglycan (PEG) from S. aureus on mast cell induction in murine skin. Methods PEG was applied to barrier-disrupted abdominal skin of mice every 5 days and the number of mast cells in the abdominal skin was counted 20 days after the first application. The cytokine response was investigated by RT-PCR and immunohistologic analysis. Results The number of mast cells in the skin of mice treated with PEG was increased significantly compared with that of mice given phosphate-buffered saline. In addition, application of PEG to the abdominal skin increased the expression of mRNA for transforming growth factor-,1 (TGF-,1), which supports mast cell migration, but not that for IL-3 or stem cell factor, which support both mast cell proliferation and mast cell migration. Immunohistologic analysis demonstrated that levels of TGF-,1 transcripts corresponded with those of protein synthesis in the epidermis. TGF-,1 was found to be highly expressed in keratinocytes of the basal epidermis of PEG-treated skin. Furthermore, intraperitoneal injection of anti-TGF-,1 antibodies neutralized the induction of mast cells into the skin. Conclusion These results suggest that PEG may have the ability to induce an increase in mast cell numbers in the skin through TGF-,1 production by epidermal keratinocytes. Skin inflammation might therefore be linked to colonization with S. aureus in AD patients. [source] | |||||||||||||