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Human Skin (human + skin)
Kinds of Human Skin Terms modified by Human Skin Selected AbstractsGlycolic Acid Treatment Increases Type I Collagen mRNA and Hyaluronic Acid Content of Human SkinDERMATOLOGIC SURGERY, Issue 5 2001Eric F. Bernstein MD Background. Chronic solar irradiation results in both morphologic and functional changes in affected skin. ,-hydroxy acids, such as glycolic acid, have been shown to improve photodamaged skin. Objective. To investigate alterations in collagen gene induction and epidermal and dermal hyaluronic acid production as a result of administered glycolic acid. Methods. In this study we compared collagen gene expression from skin biopsy specimens, and epidermal and dermal hyaluronic acid immunohistochemical staining between glycolic acid-treated and vehicle-treated skin. Forearm skin was treated with 20% glycolic acid lotion or a lotion vehicle control twice a day for 3 months. Results. Epidermal and dermal hyaluronic acid and collagen gene expression were all increased in glycolic acid-treated skin as compared to vehicle-treated controls. Conclusion. Our data suggest that epidermal and dermal remodeling of the extracellular matrix results from glycolic acid treatment. Longer treatment intervals may result in collagen deposition as suggested by the measured increase in mRNA. [source] Transfer of Triazine-iron(II) Chromic Complexes Left by Iron Items on Textile Background and Human SkinJOURNAL OF FORENSIC SCIENCES, Issue 4 2010Jakub Szumera M.Sc. Abstract:, The research is focused on the detection and transfer of iron traces left by iron items on clothing and human skin. The method is based on the formation of colored complexes between ferrous ions and five synthesized, mostly new triazines. Iron traces originally were left by iron rings on slightly wetted (artificial sweat) cotton fabrics and subsequently transferred to a separate textile substrate. Prior to the use of trazines the contact spots were treated with a new inorganic reducing agent (Sn2+) to reduce Fe3+ to Fe2+. The method is sensitive to detect iron traces on wetted canvas after 10 min contact with iron items. More spectacular results were obtained for traces left on human palm even after very short contact (10 sec). The new iron-trace-transfer method eliminated the contact of triazines solutions with human skin. Transmission visible spectra of Fe(II),triazine complexes were determined. [source] Acetylcholine-Induced Vasodilation and Reactive Hyperemia Are Not Affected by Acute Cyclo-Oxygenase Inhibition in Human SkinMICROCIRCULATION, Issue 4 2004Anne Dalle-Ave Objective: To examine whether prostaglandins are involved in endothelium-dependent vasodilatory responses of the skin microcirculation. Methods: Twenty-three young male volunteers were studied on 2 different days 1,3 weeks apart. On each experimental day the forearm skin blood flow response to iontophoretically applied acetylcholine (Ach, an endothelium-dependent vasodilator) was determined with laser Doppler imaging following the intravenous administration of either the cyclo-oxygenase inhibitor lysine acetylsalicylate (L-AS), 900 mg, or the oral intake of indomethacin, 75 mg. Acetylcholine was iontophoresed both in presence and in absence of surface anesthesia. In some subjects, the effects of L-AS on skin reactive hyperemia were also assessed. Results: Acute cyclo-oxygenase inhibition with either drug influenced neither the skin blood flow response to 4 different doses of Ach (0.28, 1.4, 7, and 14 mC/cm2) nor reactive hyperemia. The peak vasodilatory response to Ach was significantly increased by skin anesthesia, regardless of whether the subjects received the cyclo-oxygenase inhibitor or not. For example, the mean response (± SD) to the largest dose of Ach (tested in 6 subjects, expressed in perfusion units) were as follows: in absence of anesthesia: L-AS 339 ± 105, placebo 344 ± 68; with anesthesia: L-AS 453 ± 76, placebo 452 ± 65 (p < .01 for effect of anesthesia). Conclusions: These data give no support for a contribution of prostaglandins to acetylcholine-induced vasodilation or to reactive hyperemia in the skin microcirculation. In this vascular bed, local anesthesia seems to amplify acetylcholine-induced vasodilation via a prostaglandin-independent mechanism. [source] Photoprotection in Human Skin,A Multifaceted SOS Response,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2008Mark S. Eller Human skin has developed elaborate defense mechanisms for combating a wide variety of potentially damaging environmental factors; principal among these is UV light. Despite these defenses, short-term damage may include painful sunburn and long-term UV damage results in both accelerated skin aging and skin cancers such as basal cell carcinoma, squamous cell carcinoma and even malignant melanoma. While UV radiation damages many cellular constituents, its most lasting effects involve DNA alteration. The following sections briefly review UV-inducible protective responses in bacteria and in skin, thymidine dinucleotides (pTT) as a powerful probe of DNA damage responses, and potential means of harnessing these inducible responses therapeutically to reduce the now enormous burden of cutaneous photodamage in our society. [source] On the Role of Iron and one of its Chelating Agents in the Production of Protoporphyrin IX Generated by 5-Aminolevulinic Acid and its Hexyl Ester Derivative Tested on an Epidermal Equivalent of Human SkinPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2006Pascal Uehlinger ABSTRACT Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) or its derivatives as precursors of protoporphyrin IX (PPIX) is routinely used in dermatology for the treatment of various pathologies. However, this methodology suffers to some extent from a limited efficacy. Therefore, the main goal of this study was to investigate the modulation and pharma-cokinetics of PPIX buildup after a 5 h incubation with ALA (1.5 mM) and one of its derivatives, the hexyl ester of ALA (h-ALA) (1.5 mM), on the human epidermal equivalent EpidexÔ. PPIX production was modulated with (L+) ascorbic acid iron (II) salt (LAI) or the iron (II)-specific chelating agent deferoxamine (DFO). PPIX fluorescence from the EpidexÔ layers was measured up to 150 h after the precursor administration using a microspectrofluorometer (,ex: 400 ± 20 nm; ,det: 635 nm). The maximum PPIX fluorescence intensity induced by h-ALA was about 1.7x larger than that induced by ALA. The addition of DFO resulted in a more than 50% increase in PPIX fluorescence for both precursors. The decay half life measured for PPIX fluorescence is 30 and 42.5 h, respectively, for ALA and h-ALA. These half lives are doubled when the samples contain DFO. In the samples with the highest fluorescence intensity, a modified fluorescence spectrum was observed after 10 h, with the emergence of a peak at 590 nm, which is attributed to zinc protoporphyrin IX (Zn PPIX). [source] Novel Aspects of Intrinsic and Extrinsic Aging of Human Skin: Beneficial Effects of Soy Extract,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2005Kirstin M. Südel ABSTRACT Biochemical and structural changes of dermal connective tissue substantially contribute to the phenotype of aging skin. To study connective tissue metabolism with respect to ultraviolet (UV) exposure, we performed an in vitro (human dermal fibroblasts) and an in vivo complementary DNA array study in combination with protein analysis in young and old volunteers. Several genes of the collagen metabolism such as Collagen I, III and VI as well as heat shock protein 47 and matrix metalloproteinase-1 are expressed differentially, indicating UV-mediated effects on collagen expression, processing and degradation. In particular, Collagen I is time and age dependently reduced after a single UV exposure in human skin in vivo. Moreover, older subjects display a lower baseline level and a shorter UV-mediated increase in hyaluronan (HA) levels. To counteract these age-dependent changes, cultured fibroblasts were treated with a specific soy extract. This treatment resulted in increased collagen and HA synthesis. In a placebo-controlled in vivo study, topical application of an isoflavone-containing emulsion significantly enhanced the number of dermal papillae per area after 2 weeks. Because the flattening of the dermal-epidermal junction is the most reproducible structural change in aged skin, this soy extract appears to rejuvenate the structure of mature skin. [source] Adaptation of the Human Skin by Chronic Solar-simulating UV Irradiation Prevents Ultraviolet-B Irradiation-induced Rise in Serum C-Reactive Protein Levels,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2005Jarmo K. Laihia ABSTRACT Exposure of the skin to UV radiation induces local inflammation. We hypothesized that inflammation induced by erythemal UV-B irradiation could elevate levels of serum C-reactive protein (CRP) and that suberythemal repeating doses of solar-simulating UV radiation (SSR) would produce photoadaptation to such inflammation. Separation-free high-sensitivity assays of CRP show an increase by 42% (P= 0.046) in CRP concentrations in healthy human subjects 24 h after a 3 minimal erythemal dose (MED) dose of UV-B delivered onto a 100 cm2 skin area. Preceding daily suberythemal doses of whole-body SSR for 10 or 30 consecutive days completely prevented the CRP increase. UV-B-induced skin erythema was partially attenuated by 30 preceding days of SSR only (P= 0.00066). After 10 daily SSR doses, the mean baseline CRP concentrations (0.24 ± 0.21 mg/L) declined by 35% (P= 0.018). Using high-sensitivity analysis of serum CRP as the endpoint marker for cutaneous inflammation, we show that acute exposure of even a relatively small skin area to erythemal UV-B induces skin inflammation detectable also at the systemic level and that photoadaptation by preceding repeating suberythemal doses of SSR reduces signs of inflammation. Our data complement the view given by previous studies in that local photoadaptation also has systemic manifestations. [source] UVB Irradiation of Normal Human Skin Favors the Development of Type-2 T-cells In Vivo and in Primary Dermal Cell Cultures,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2002Sergio Di Nuzzo ABSTRACT To determine the effect of UVB exposure on the balance of type-1 or type-2 T-cells in skin, we examined the expression of key markers interferon (IFN)-, and interleukin (IL)-4 in cryostat sections. IFN-, mRNA was clearly detectable in nonirradiated control skin, and IFN-, protein was found in 2% of the dermal CD3pos T-cells, whereas IL-4 mRNA was hardly detectable, and no IL-4 protein was found. In contrast, IL-4 mRNA expression increased upon irradiation, and IL-4 was found in 2% of the T-cells at day 2 after UVB-exposure. Concomitantly, IFN-, mRNA expression decreased, and IFN-, protein became absent. We also analyzed T-cells present in primary dermal cell cultures, which were used as an in vitro equivalent of the in vivo situation. As compared with T-cells from control skin, T-cells in dermal cell cultures from UVB-exposed skin displayed an increased IL-4 and decreased IFN-, expression. No such skewing occurred when the T-cells from irradiated skin were cloned in the absence of a dermal microenvironment. Except for an occasional positive T-cell, type-1,associated cell-surface markers (CCR5, CXCR3) or type-2 markers (CCR3, CD30, CRTH2) were undetectable in situ. But these markers were expressed on cultured dermal T-cells from UVB-exposed and control skin at a comparable level, but did not correlate with the IFN-, and IL-4 production. Altogether, UVB-induced changes of the dermal microenvironment favor the development of type-2 T-cells. [source] Activation of HIV in Human Skin by Ultraviolet B Radiation and its Inhibition by NF,B Blocking Agents,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2001Joan Breuer-McHam ABSTRACT To determine whether ultraviolet B (UVB) irradiation leads to activation of HIV in human skin, we conducted prospective and controlled studies in two academic medical centers in Texas from July 1995 to April 1999. HIV-positive patients with UV-treatable skin diseases were enrolled at each center, 18 subjects at one and 16 at the other. In one center, specimens from lesional and nonlesional skin biopsies were taken before and after sham- or UVB-irradiation administered in vivo or in vitro. In the other center, UVB phototherapy was administered three times weekly and specimens from skin biopsies were taken before and after 2 weeks (six treatments). Cutaneous HIV load was assessed using reverse transcriptase-polymerase chain reaction and reverse transcriptase-polymerase chain reaction in situ hybridization. UVB irradiation led to a 6,10-fold increase in the number of HIV in skin. To ascertain a role for nuclear factor kappa B (NF,B) in UVB-inducible HIV activation, two types of blockers, NF,B oligonucleotide decoy and sodium salicylate, were tested; each inhibited UVB-inducible HIV activation in skin partially. We conclude that UVB irradiation leads to increased numbers of HIV in human skin via processes that include release of cytoplasmic NF,B. [source] Production of Melanocyte-Specific Antibodies to Human Melanosomal Proteins: Expression Patterns in Normal Human Skin and in Cutaneous Pigmented LesionsPIGMENT CELL & MELANOMA RESEARCH, Issue 4 2001Victoria Virador Multiple factors affect skin pigmentation, including those that regulate melanocyte and/or keratinocyte function. Such factors, particularly those that operate at the level of the melanosome, are relatively well characterized in mice, but the expression and function of structural and enzymatic proteins in melanocytes in human skin are not as well known. Some years ago, we generated peptide-specific antibodies to murine melanosomal proteins that proved to be instrumental in elucidating melanocyte development and differentiation in mice, but cross-reactivity of those antibodies with the corresponding human proteins often was weak or absent. In an effort to characterize the roles of melanosomal proteins in human skin pigmentation, and to understand the underlying mechanism(s) of abnormal skin pigmentation, we have now generated polyclonal antibodies against the human melanocyte-specific markers, tyrosinase, tyrosinase-related protein 1 (TYRP1), Dopachrome tautomerase (DCT) and Pmel17 (SILV, also known as GP100). We used these antibodies to determine the distribution and function of melanosomal proteins in normal human skin (adult and newborn) and in various cutaneous pigmented lesions, such as intradermal nevi, lentigo simplex, solar lentigines and malignant melanomas. We also examined cytokeratin expression in these same samples to assess keratinocyte distribution and function. Immunohistochemical staining reveals distinct patterns of melanocyte distribution and function in normal skin and in various types of cutaneous pigmented lesions. Those differences in the expression patterns of melanocyte markers provide important clues to the roles of melanocytes in normal and in disrupted skin pigmentation. [source] Human skin: source of and target organ for angiotensin IIEXPERIMENTAL DERMATOLOGY, Issue 3 2004U. Muscha Steckelings Abstract:, The present study examined the expression of angiotensin receptors in human skin, the potential synthesis of angiotensin II (Ang II) in this location and looked for a first insight into physiological functions. AT1 and AT2 receptors were found within the epidermis and in dermal vessel walls. The same expression pattern was found for angiotensinogen, renin and angiotensin-converting enzyme (ACE). All components could additionally be demonstrated at mRNA level in cultured primary keratinocytes, melanocytes, dermal fibroblasts and dermal microvascular endothelial cells, except for AT2 receptors in melanocytes. The ability of cutaneous cells to synthesize Ang II was proved by identifying the molecule in cultured keratinocytes. Furthermore, in artificially wounded keratinocyte monolayers, ACE-mRNA expression was rapidly increased, and enhanced ACE expression was still found in cutaneous human scars 3 months after wounding. These findings suggest that the complete renin,angiotensin system is present in human skin and plays a role in normal cutaneous homeostasis as well as in human cutaneous wound healing. [source] Human skin permeation and partition: General linear free-energy relationship analysesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2004Michael H. Abraham Abstract Literature values of the permeability coefficient for permeation of human skin from water have been adjusted for ionization in water and adjusted for temperature. The obtained values of log Kp for 119 solutes at 37°C have been correlated with Abraham descriptors to yield an equation with R2,=,0.832 and SD,=,0.46 log units. Three separate test sets of 60 compounds had log Kp predicted with an SD of 0.48 log units. The main factors that influence log Kp are solute hydrogen bond basicity that lowers the permeability coefficient and solute volume that increases the permeability coefficient. Human skin,water partition coefficients, as log Ksc, have been collected for 45 compounds and yield an equation with R2,=,0.926 and SD,=,0.22 log units. We have compared the log Kp equation to equations for various other processes, but have found no process that appears to be similar to that for skin permeation. The nearest process to skin,water partition is the isobutanol,water partition system. An equation for lateral diffusion in the stratum corneum is shown to be reasonably close to various diffusion-related processes. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93:1508,1523, 2004 [source] Photoprotection in Human Skin,A Multifaceted SOS Response,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2008Mark S. Eller Human skin has developed elaborate defense mechanisms for combating a wide variety of potentially damaging environmental factors; principal among these is UV light. Despite these defenses, short-term damage may include painful sunburn and long-term UV damage results in both accelerated skin aging and skin cancers such as basal cell carcinoma, squamous cell carcinoma and even malignant melanoma. While UV radiation damages many cellular constituents, its most lasting effects involve DNA alteration. The following sections briefly review UV-inducible protective responses in bacteria and in skin, thymidine dinucleotides (pTT) as a powerful probe of DNA damage responses, and potential means of harnessing these inducible responses therapeutically to reduce the now enormous burden of cutaneous photodamage in our society. [source] Cutaneous effects of infrared radiation: from clinical observations to molecular response mechanismsPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2003Stefan M. Schieke Human skin is exposed to infrared (IR) radiation (760 nm,1 mm) from natural as well as artificial sources that are increasingly used for cosmetic or medical purposes. Epidemiological data and clinical observations, however, indicate that IR radiation cannot be considered as totally innocuous to human skin. In particular, IR radiation, similar to ultraviolet radiation, seems to be involved in photoaging and potentially also in photocarcinogenesis. The molecular consequences resulting from IR exposure are virtually unknown. Recent studies, however, have begun to shed light on the basic molecular processes such as cellular signal transduction and gene expression triggered by exposure to IR radiation. In response to IR irradiation, mitogen-activated protein kinase signaling pathways were activated mediating the upregulation of matrix metalloproteinase-1 expression. This previously unrecognized molecular ,IR response' shows that IR radiation is capable of specifically interfering with cellular functions and provides a molecular basis for biological effects of IR on human skin. [source] Angiogenesis in skin aging and photoagingTHE JOURNAL OF DERMATOLOGY, Issue 9 2007Jin Ho CHUNG ABSTRACT Angiogenesis, the process of generating new blood vessels, is affected by various physiological and pathological conditions of skin. The skin aging process can be divided into intrinsic aging and photoaging. With aging, cutaneous blood vessels undergo pronounced alterations. A reduction of the cutaneous microvasculature has been observed in the skin of elderly individuals. Human skin is exposed daily to solar ultraviolet (UV) radiation, infrared rays and heat, and these stimuli are known to induce skin angiogenesis. Interestingly, although acute UV irradiation stimulates skin angiogenesis, cutaneous blood vessels are decreased in chronically photodamaged skin. The reason for the differential effects of acute and chronic UV exposure on skin angiogenesis remains to be elucidated. This review discusses the vascularization changes in intrinsically aged and photoaged human skin, the effects of UV irradiation, infrared rays and heat on skin angiogenesis, and the effects of topical retinoic acid treatment on UV-induced angiogenesis and cutaneous vascularity in aged and photoaged human skin. An understanding of the molecular mechanisms of aging- and photoaging-dependent changes of skin angiogenesis may provide us with new insights to prevent and treat the skin aging process. [source] Thyrotropin-releasing hormone and oestrogen differentially regulate prolactin and prolactin receptor expression in female human skin and hair follicles in vitroBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2010E.A. Langan Summary Background, Human skin and scalp hair follicles are both a nonclassical target and an extrapituitary source of prolactin (PRL), which is a potent hair growth modulator. However, how the expression of PRL and PRL receptor (PRLR) is regulated in human skin is unknown. Objectives, To investigate whether two key stimulators of pituitary PRL secretion, thyrotropin-releasing hormone (TRH) and oestrogen, also regulate cutaneous PRL and PRLR expression. Methods, Female scalp skin and/or microdissected hair follicles were treated for 6 days in serum-free organ culture with oestrogen (100 nmol L,1), TRH (1,10 ng mL,1, 3,30 nm) or vehicle control. Quantitative immunohistomorphometry of skin and hair follicle sections was complemented with quantitative polymerase chain reaction for PRL and PRLR in cultured hair follicles and/or female human outer root sheath (ORS) keratinocytes. Results, Oestrogen treatment significantly upregulated PRL and PRLR immunoreactivity in selected skin and hair follicle compartments, at the gene and protein level (P < 0·05). TRH significantly increased PRL immunoreactivity and transcription in hair follicles (P < 0·05); however, while it also increased PRLR transcription in hair follicles, it downregulated PRLR immunoreactivity in the hair follicle ORS (P < 0·05). Conclusions, Our pilot study shows that two key endocrine controls of pituitary PRL secretion, oestrogen and TRH, also regulate PRL and PRLR expression in human skin. This provides novel insights into the regulation of extrapituitary PRL and PRLR expression, and invites exploration of oestrogen and TRH as novel therapeutic agents in the management of skin and hair diseases characterized by aberrant PRLR-mediated signalling. [source] Topical PTH (1,34) is a novel, safe and effective treatment for psoriasis: a randomized self-controlled trial and an open trialBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2003M.F. Holick Summary Background There continues to be a need to develop new pharmacological approaches for treating the common skin disease psoriasis. Human skin produces parathyroid hormone related peptide. This peptide is a potent inhibitor of epidermal cell growth. Objectives A programme was initiated to determine whether an agonist of this peptide's receptor, PTH (1,34), could be developed as a drug to treat psoriasis. Methods PTH (1,34) was formulated in Novasome A® cream. Fifteen adult patients with chronic plaque psoriasis who had failed to respond to at least one standard treatment were enrolled in a randomized double-blinded placebo self-controlled trial. The patients topically applied to a 25-cm2 psoriatic lesion 0·1 g of either Novasome A® cream or Novasome A® cream that contained 20 ,g of PTH (1,34) twice a day for 2 months. At the end of the double-blind study, patients were enrolled in an open large area study. Ten patients applied PTH (1,34) (50 ,g per 0·1 g) once daily to their psoriatic lesions. The patients were evaluated for their global improvement and calcium metabolism. Results Novasome A® cream enhanced the percutaneous absorption of PTH (1,34) in human skin in comparison with formulations in propylene glycol or normal saline. Psoriatic lesions treated with PTH (1,34) showed marked improvement in scaling, erythema and induration. There was a 67·3% improvement in the global severity score for the lesion treated with PTH (1,34) compared with the placebo-treated lesion, which only showed a 17·8% improvement. Ten patients topically applied PTH (1,34) on all of their lesions in a stepwise manner. A Psoriasis Area and Severity Index score analysis of all the patients revealed improvement of 42·6% (P < 0·02). None of the patients experienced hypercalcaemia or hypercalciuria or developed any side-effect to the medication. Conclusions Patients who were resistant to at least one standard therapy for psoriasis had a remarkable improvement in their psoriasis when they applied PTH (1,34) to their lesion(s). No untoward toxicity was observed in any of the subjects. This pilot study suggests that topical PTH (1,34) is a safe and effective novel therapy for psoriasis. [source] Partial reversal of conduction slowing during repetitive stimulation of single sympathetic efferents in human skinACTA PHYSIOLOGICA, Issue 3 2004M. Campero Abstract Aims:, To describe and identify the function of a class of human C fibre with an unusual response to repetitive electrical stimulation. Other C fibres slow progressively at 2 Hz (type 1), reach a latency plateau (type 2) or hardly slow at all (type 3). Methods:, C fibres innervating hairy skin were recorded by microneurography in the superficial peroneal nerves of 19 healthy volunteers. Baseline electrical stimulation of the skin was at 0.25 Hz, and activity-dependent slowing recorded during stimulation at 2 Hz for 3 min and after a 3-min pause in stimulation. Results:, In 41 units, there was a partial recovery of latency during repetitive stimulation. These were classified as ,type-4' units, and identified as sympathetic efferents, since they exhibited spontaneously activity, which was enhanced by manoeuvres that increase sympathetic outflow (15 of 16 cases) and/or suppressed by a proximal anaesthetic block (eight of eight cases). The peak slowing during 2 Hz trains averaged 6.47 ± 2.06% (mean ± SD, n = 41), but after 3 min the slowing had reduced to 4.90 ± 2.20%, which was less than in all type 1 (nociceptor) fibres but similar to that in type 2 (cold) fibres. Compared with cold fibres, type-4 sympathetic fibres slowed more after the first 10 impulses at 2 Hz (2.57 ± 0.45%) and also after a pause in stimulation (1.66 ± 0.51%). Conclusions:, The distinctive activity-dependent slowing profiles of these type-4 sympathetic C units may help identification in vitro, and suggest that hyperpolarization-activated channels have a particularly prominent role in the axonal membrane. [source] The Polyhydroxy Acid Gluconolactone Protects Against Ultraviolet Radiation in an In Vitro Model of Cutaneous PhotoagingDERMATOLOGIC SURGERY, Issue 2 2004Eric F. Bernstein MD Background. Ultraviolet (UV) radiation damages skin through a variety of mechanisms, including the generation of free radicals. Gluconolactone is a polyhydroxy acid (PHA) that is capable of chelating metals and may also function by scavenging free radicals, thereby protecting skin from some of the damaging effects of UV radiation. Objective. This study measured the ability of gluconolactone to protect against UV radiation,induced damage. Methods. The ability of gluconolactone to prevent UV radiation,induced elastin promoter activation was determined in vitro using a transgenic model of cutaneous photoaging. Gluconolactone was also evaluated to determine its ability to promote the formation of sunburn cells in human skin after exposure to UV radiation. Results. Gluconolactone provided up to 50% protection against UV radiation, as measured in our in vitro system, and did not significantly increase sunburn cells in human skin. Conclusions. These results demonstrate the ability of the PHA gluconolactone to protect against UV radiation,induced elastin promoter activation. In addition, in vivo studies demonstrated that gluconolactone treatment does not result in a significant increase in sunburn cells. Further investigation of this and other PHAs is necessary to identify their potential role in preventing and repairing cutaneous photodamage. [source] Cnidarians and human skinDERMATOLOGIC THERAPY, Issue 1 2002William A. Burke Cnidarians are aquatic animals including the jellyfish, the Portuguese man-of-war, fire coral, hydroids, sea anemones, and coral. Many of these can harm human skin and rarely some envenomations can lead to a serious or even fatal outcome. This article discusses the varied creatures in this group that can harm man and potentially lead to serious envenomation syndromes. Treatment of cnidarian injuries and stings is discussed. [source] Arsenate and dimethylarsinic acid in drinking water did not affect DNA damage repair in urinary bladder transitional cells or micronuclei in bone marrow,ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2009Amy Wang Abstract Arsenic is a human skin, lung, and urinary bladder carcinogen, and may act as a cocarcinogen in the skin and urinary bladder. Possible modes of action of arsenic carcinogenesis/cocarcinogenesis include oxidative stress induction and inhibition of DNA damage repair. We investigated the effects of arsenic in drinking water on DNA damage repair in urinary bladder transitional cells and on micronucleus formation in bone marrow. F344 rats were given 100 ppm arsenate [As(V)] or dimethylarsinic acid [DMA(V)] in drinking water for 1 week. The in vivo repair of cyclophosphamide (CP)-induced DNA damage resulting from a single oral gavage of CP, and the in vitro repair of hydrogen peroxide (H2O2)- or formaldehyde-induced DNA damage, resulting from adding H2O2 or formaldehyde into cell medium, were measured by the Comet assay. DMA(V) effects were not observed on either CP-induced DNA damage induction or on DNA repair. Neither DMA(V) nor As(V) increased the H2O2 - or formaldehyde-induced DNA damage, and neither inhibited the repair of H2O2 -induced DNA damage. Neither DMA(V) nor As(V) increased the micronucleus frequency, nor did they elevate micronucleus frequency resulting from CP treatment above the level observed by the treatment with CP alone. These results suggest that arsenic carcinogenesis/cocarcinogenesis in the urinary bladder may not be via DNA damage repair inhibition. To our knowledge this is the first report of arsenic effects on DNA damage repair in the urinary bladder. Environ. Mol. Mutagen. 2009. Published 2009 by Wiley-Liss, Inc. [source] Proteomic profiling reveals a catalogue of new candidate proteins for human skin agingEXPERIMENTAL DERMATOLOGY, Issue 10 2010Martin Laimer Abstract:, Studies of skin aging are usually performed at the genomic level by investigating differentially regulated genes identified through subtractive hybridization or microarray analyses. In contrast, relatively few studies have investigated changes in protein expression of aged skin using proteomic profiling by two-dimensional (2-D) gel electrophoresis and mass spectrometry, although this approach at the protein level is suggested to reflect more accurately the aging phenotype. We undertook such a proteomic analysis of intrinsic human skin aging by quantifying proteins extracted and fluorescently labeled from sun-protected human foreskin samples pooled from ,young' and ,old' men. In addition, we analyzed these candidate gene products by 1-D and 2-D western blotting to obtain corroborative protein expression data, and by both real-time PCR (RT-PCR) and microarray analyses to confirm expression at the mRNA level. We discovered 30 putative proteins for skin aging, including previously unrecognized, post-translationally regulated candidates such as phosphatidyl-ethanolamine binding protein (PEBP) and carbonic anhydrase 1 (CA1). [source] Reproducible pattern of microRNA in normal human skinEXPERIMENTAL DERMATOLOGY, Issue 8 2010Line Marie Holst Please cite this paper as: Reproducible pattern of microRNA in normal human skin. Experimental Dermatology 2010; 19: e201,e205. Abstract:, MicroRNAs (miRNAs) regulate cell growth, differentiation and apoptosis via specific targeting of messenger RNA (mRNA). Aberrant mRNA expression contributes to pathological processes such as carcinogenesis. To take advantage of miRNA profiling in skin disease it is essential to investigate miRNA expression pattern in normal human skin. Here we investigated miRNA expression profiles from skin biopsies of 8 healthy volunteers taken from sun protected and mildly photo damaged skin using the modified protocol for miRNA extraction. We were able to show a constant pattern of miRNA expression between different individuals. We did not find any significant differences in miRNA expression between sun protected and mildly photodamaged skin. These results may be valuable for future design of studies on miRNA expression in skin disease. [source] Functional characterization of highly adherent CD34+ keratinocytes isolated from human skinEXPERIMENTAL DERMATOLOGY, Issue 7 2010Araika Gutiérrez-Rivera Please cite this paper as: Functional characterization of highly adherent CD34+ keratinocytes isolated from human skin. Experimental Dermatology 2010; 19: 685,688. Abstract:, Compared to murine models, data on cells responsible for the homeostasis of human epidermis are scarce and often contradictory. Given the conflicting results and the availability of clinical grade protocols to purify CD34 cells from a given tissue, we pursued to phenotypically characterize human epidermal CD34+ population. After magnetic separation of whole skin CD34+ and CD34, cell fractions and selection for cells highly adherent to extracellular matrix, both CD34± fractions retained the ability to form a stratified epidermis in organotypic cultures and presented similar in vitro migratory phenotypes. However CD34, cells showed higher clonogenic potential and in vitro proliferative capacity. These results indicated that CD34, cell fraction contains stem/early progenitor cells, while CD34+ cells might be a transit-amplifying precursor for hair follicle (HF) sheath cells. The ability to isolate living cells using differential cell adhesion and surface markers provides an opportunity to study cells from different morphological regions of the HF. [source] Sodium lauryl sulphate alters the mRNA expression of lipid-metabolizing enzymes and PPAR signalling in normal human skin in vivoEXPERIMENTAL DERMATOLOGY, Issue 12 2009Hans Törmä Abstract:, Detergents irritate skin and affect skin barrier homeostasis. In this study, healthy skin was exposed to 1% sodium lauryl sulphate (SLS) in water for 24 h. Biopsies were taken 6 h to 8 days post exposure. Lipid patterns were stained in situ and real-time polymerase chain reaction (PCR) was used to examine mRNA expression of enzymes synthesizing barrier lipids, peroxisome proliferator-activated receptors (PPAR) and lipoxygenases. The lipid pattern was disorganized from 6 h to 3 days after SLS exposure. Concomitant changes in mRNA expression included: (i) reduction, followed by induction, of ceramide-generating ,-glucocerebrosidase, (ii) increase on day 1 of two other enzymes for ceramide biosynthesis and (iii) persistent reduction of acetyl-CoA carboxylase-B, a key enzyme in fatty acid synthesis. Surprisingly, the rate-limiting enzyme in cholesterol synthesis, HMG-CoA reductase, was unaltered. Among putative regulators of barrier lipids synthesis, PPAR, and PPAR, exhibited reduced mRNA expression, while PPAR,/, and LXR, were unaltered. Epidermal lipoxygenase-3, which may generate PPAR, agonists, exhibited reduced expression. In conclusion, SLS induces reorganization of lipids in the stratum corneum, which play a role in detergents' destruction of the barrier. The changes in mRNA expression of enzymes involved in synthesizing barrier lipids are probably important for the restoration of the barrier. [source] Extracts from Glycine max (soybean) induce elastin synthesis and inhibit elastase activityEXPERIMENTAL DERMATOLOGY, Issue 10 2009Renbin Zhao Abstract:, Elastic fibres are essential extracellular matrix components of the skin, contributing to its resilience and elasticity. In the course of skin ageing, elastin synthesis is reduced, and elastase activity is accelerated, resulting in skin sagging and reduced skin elasticity. Our studies show that non-denatured Glycine max (soybean) extracts induced elastin promoter activity, inhibited elastase activity and protected elastic fibres from degradation by exogenous elastases in vitro. Mouse and swine skins topically treated with soybean extracts showed enhanced elastic fibre network and increased desmosine content. Elastin expression was also augmented in human skin transplanted onto SCID mice in response to soy treatment. These data suggest that non-denatured soybean extracts may be used as skin care agents to reduce the signs of skin ageing. [source] The human skin/chick chorioallantoic membrane model accurately predicts the potency of cosmetic allergensEXPERIMENTAL DERMATOLOGY, Issue 4 2009Dan Slodownik Abstract:, The current standard method for predicting contact allergenicity is the murine local lymph node assay (LLNA). Public objection to the use of animals in testing of cosmetics makes the development of a system that does not use sentient animals highly desirable. The chorioallantoic membrane (CAM) of the chick egg has been extensively used for the growth of normal and transformed mammalian tissues. The CAM is not innervated, and embryos are sacrificed before the development of pain perception. The aim of this study was to determine whether the sensitization phase of contact dermatitis to known cosmetic allergens can be quantified using CAM-engrafted human skin and how these results compare with published EC3 data obtained with the LLNA. We studied six common molecules used in allergen testing and quantified migration of epidermal Langerhans cells (LC) as a measure of their allergic potency. All agents with known allergic potential induced statistically significant migration of LC. The data obtained correlated well with published data for these allergens generated using the LLNA test. The human-skin CAM model therefore has great potential as an inexpensive, non-radioactive, in vivo alternative to the LLNA, which does not require the use of sentient animals. In addition, this system has the advantage of testing the allergic response of human, rather than animal skin. [source] Lipophilic and hydrophilic moisturizers show different actions on human skin as revealed by cryo scanning electron microscopyEXPERIMENTAL DERMATOLOGY, Issue 11 2007Julia Caussin Abstract:, To study the mode of action of moisturizers on human skin, hydrophilic moisturizers in water and neat lipophilic moisturizers were applied on excised skin for 24 h at 32°C. Samples of the treated skin were subsequently visualized in a cryoscanning electron microscope. The stratum corneum (SC) appeared as a region of swollen corneocytes (the swollen region) sandwiched between two layers of relatively dry corneocytes (the upper and lower non-swelling regions respectively). Lipophilic moisturizers increased the water content of the SC, whereas hydrophilic moisturizers can also reduce the water content of the SC. When focusing on the effect of the moisturizers on the three different regions, it was observed that cells in the swelling region are most sensitive to the application of the moisturizers and that the change in SC thickness is most influenced by the change in the thickness of the swelling region. Summarizing, SC cells are not equally sensitive to moisturizer application: centrally located corneocytes are more sensitive than corneocytes in the upper and the lowest regions of the SC. [source] Expression pattern of somatostatin receptor subtypes 1,5 in human skin: an immunohistochemical study of healthy subjects and patients with psoriasis or atopic dermatitisEXPERIMENTAL DERMATOLOGY, Issue 12 2006Lena Hagströmer Abstract:, In psoriasis and atopic dermatitis, the inflammatory events have neurogenic components and the neuropeptides modify the functions of immuno-active cells in the skin. Somatostatin is a neuropeptide with several neuroendocrine and immunomodulating properties and mediates its actions by five distinct subtypes of G-protein-coupled receptors (SSTR1-5). This study describes the distribution of SSTR1,5, analysed with immunohistochemistry, in psoriasis, atopic dermatitis and controls. Normal human skin and lesional skin from patients with psoriasis or atopic dermatitis showed many similarities, but also some differences, as regards SSTR expression. SSTR1,3 were strongly expressed in the epidermis of healthy skin, and in the skin of patients with psoriasis or atopic dermatitis. It is noteworthy that SSTR4 and 5 were strongly expressed in the epidermis of psoriasis patients, but weakly expressed in the epidermis of those with atopic dermatitis and normal skin. The intensity of the staining also varied considerably between the different layers of the epidermis, especially in psoriasis patients. In all cases, the dendritic cells, found mostly in the papillary and upper reticular dermis, showed a strong expression of SSTR1,4, but a weak expression of SSTR5. SSTR1,5 were strongly expressed in the sweat glands in all skin biopsies. Hair follicles and sebaceous glands expressed all five subtypes. Striated muscle fibres showed an intense positive expression of SSTR1,4, but a weak or negative expression of SSTR5. The wide distribution and expression pattern of all five SSTRs in human skin suggest that somatostatin is involved in the interactions between the nervous system and the skin. [source] Stimulation of keratinocyte differentiation , a new role for the vanilloid receptor subtype 1 (VR1/TRPV1)?EXPERIMENTAL DERMATOLOGY, Issue 2 2005Sonja Ständer Vanilloids and endogenous cannabinoids mediate their actions via the vanilloid receptor subtype 1 (VR1/TRPV1), a non-selective cation channel, which is widely distributed in the central and peripheral nervous system. Only recently, VR1 has been shown to be expressed in keratinocytes in vitro and in vivo. However, a precise description of VR1 localization in epithelial cells was missing. To determine this, we investigated VR1-immunoreactivity as well as mRNA and protein expression in a series of biopsies from normal, diseased, and capsaicin-treated human skin. VR1 was found in epidermal keratinocytes, the inner root sheet and the infundibulum of hair follicles, differentiated sebocytes, sweat gland ducts, and the secretory portion of eccrine sweat glands upon immunohistochemistry, RT-PCR and Western blot analysis. Interestingly, in diseased skin such as prurigo nodularis, psoriasis vulgaris, and atopic dermatitis, VR1 expression in keratinocytes correlated with the degree of epidermal differentiation. Enhanced VR1 immunoreactivity and protein content was found in prurigo nodularis in which epidermal keratinocytes are highly differentiated. Under effective capsaicin therapy of prurigo nodularis, the epidermis thinned and the distribution pattern of VR1 on epidermal keratinocytes normalized. In psoriasis vulgaris, a disease with disturbed epidermal differentiation, less intense immunostaining for VR1 was observed. This could be confirmed by western blot analysis showing less VR1 protein amount in comparison to prurigo nodularis although histologically both showed a thickened epidermis. In atopic dermatitis, which is characterized by a moderate epidermal hyperplasia only and regular differentiated keratinocytes, VR1 immunoreactivity was unchanged in comparison to normal skin. These findings suggest that VR1 may contribute to regular differentiation of keratinocytes. VR1 activation opens non-selective cation channels with high permeability to calcium, a ion that is crucially important for the synthesis of cornification proteins such as involucrin, fillagrin and loricrin. The role of VR1 in other epithelial cells of appendage structures remains to be determined. In summary, VR1 is widely distributed in the skin suggesting a central role for this receptor not only in nociception but also maturation and function of epithelial cells. [source] | |||||||||||||||||||