WorldWideScience

Sample records for chemical skin sensitizers

  1. Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

    OpenAIRE

    Alves, Vinicius M.; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Carolina H. Andrade; Tropsha, Alexander

    2015-01-01

    Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop ...

  2. Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

    International Nuclear Information System (INIS)

    Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, we found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R2 = 0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q2ext = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. - Highlights: • It was compiled the largest publicly-available skin permeability dataset. • Predictive QSAR models were developed for skin permeability. • No concordance between skin sensitization and skin

  3. Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Vinicius M. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Muratov, Eugene [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Laboratory of Theoretical Chemistry, A.V. Bogatsky Physical–Chemical Institute NAS of Ukraine, Odessa 65080 (Ukraine); Fourches, Denis [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Strickland, Judy; Kleinstreuer, Nicole [ILS/Contractor supporting the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), P.O. Box 13501, Research Triangle Park, NC 27709 (United States); Andrade, Carolina H. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Tropsha, Alexander, E-mail: alex_tropsha@unc.edu [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States)

    2015-04-15

    Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, we found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R{sup 2} = 0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q{sup 2}{sub ext} = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. - Highlights: • It was compiled the largest publicly-available skin permeability dataset. • Predictive QSAR models were developed for skin permeability. • No concordance between skin

  4. [Recent development in animal testing to predict the skin and respiratory sensitizing potential of chemicals].

    Science.gov (United States)

    Aoyama, Kohji

    2010-01-01

    The identification of chemicals with skin and/or respiratory sensitizing potential is important for the prevention of allergic diseases in both living and work environments. Although a number of animal models for respiratory allergic diseases have been reported, none of these models meets the goals of broad assessments of chemical sensitizing potential. We are attempting to develop a test for predicting the respiratory sensitization of chemicals. In the evaluation of skin sensitization of chemicals, the mostly used predictive tests are the guinea pig maximization test, Buehler test, and mouse local lymph node assay (LLNA). However, only LLNA has been validated formally and independently. Recent studies have revealed that EC3 estimated by LLNA correlates well with human skin sensitizing potency and the threshold for the induction of skin sensitization in the human repeat patch test. Thus, LLNA can predict the potency of skin sensitizing potential of a chemical and its risk in humans. PMID:20134104

  5. Identifying and characterizing chemical skin sensitizers without animal testing: Colipa's research and method development program.

    Science.gov (United States)

    Aeby, P; Ashikaga, T; Bessou-Touya, S; Schepky, A; Gerberick, F; Kern, P; Marrec-Fairley, M; Maxwell, G; Ovigne, J-M; Sakaguchi, H; Reisinger, K; Tailhardat, M; Martinozzi-Teissier, S; Winkler, P

    2010-09-01

    The sensitizing potential of chemicals is usually identified and characterized using one of the available animal test methods, such as the mouse local lymph node assay. Due to the increasing public and political concerns regarding the use of animals for the screening of new chemicals, the Colipa Skin Tolerance Task Force collaborates with and/or funds research groups to increase and apply our understanding of the events occurring during the acquisition of skin sensitization. Knowledge gained from this research is used to support the development and evaluation of novel alternative approaches for the identification and characterization of skin sensitizing chemicals. At present one in chemico (direct peptide reactivity assay (DPRA)) and two in vitro test methods (cell based assays (MUSST and h-CLAT)) have been evaluated within Colipa inter-laboratory ring trials and accepted by the European Centre for the Validation of Alternative Methods (ECVAM) for pre-validation. Data from all three test methods will be used to support the development of testing strategy approaches for skin sensitizer potency prediction. The replacement of the need for animal testing for skin sensitization risk assessment is viewed as ultimately achievable and the next couple of years should set the timeline for this milestone. PMID:20624454

  6. Development and validation of animal-free test methods to predict the skin sensitizing potential of chemicals

    OpenAIRE

    Bauch, Caroline D.

    2013-01-01

    Skin sensitization is the development of the allergic contact dermatitis caused by chemicals. Regulatory accepted methods to assess skin sensitizing potential of chemicals are animal based tests, but increasing interest in animal welfare presses the development of animal-free methods. The aim of this work was the development, establishment and validation of several alternative methods to animal testing to predict the skin sensitizing potential of chemicals. Therefore several methods reflectin...

  7. Predicting chemically-induced skin reactions. Part I: QSAR models of skin sensitization and their application to identify potentially hazardous compounds

    International Nuclear Information System (INIS)

    Repetitive exposure to a chemical agent can induce an immune reaction in inherently susceptible individuals that leads to skin sensitization. Although many chemicals have been reported as skin sensitizers, there have been very few rigorously validated QSAR models with defined applicability domains (AD) that were developed using a large group of chemically diverse compounds. In this study, we have aimed to compile, curate, and integrate the largest publicly available dataset related to chemically-induced skin sensitization, use this data to generate rigorously validated and QSAR models for skin sensitization, and employ these models as a virtual screening tool for identifying putative sensitizers among environmental chemicals. We followed best practices for model building and validation implemented with our predictive QSAR workflow using Random Forest modeling technique in combination with SiRMS and Dragon descriptors. The Correct Classification Rate (CCR) for QSAR models discriminating sensitizers from non-sensitizers was 71–88% when evaluated on several external validation sets, within a broad AD, with positive (for sensitizers) and negative (for non-sensitizers) predicted rates of 85% and 79% respectively. When compared to the skin sensitization module included in the OECD QSAR Toolbox as well as to the skin sensitization model in publicly available VEGA software, our models showed a significantly higher prediction accuracy for the same sets of external compounds as evaluated by Positive Predicted Rate, Negative Predicted Rate, and CCR. These models were applied to identify putative chemical hazards in the Scorecard database of possible skin or sense organ toxicants as primary candidates for experimental validation. - Highlights: • It was compiled the largest publicly-available skin sensitization dataset. • Predictive QSAR models were developed for skin sensitization. • Developed models have higher prediction accuracy than OECD QSAR Toolbox. • Putative

  8. Predicting chemically-induced skin reactions. Part I: QSAR models of skin sensitization and their application to identify potentially hazardous compounds

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Vinicius M. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Muratov, Eugene [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Laboratory of Theoretical Chemistry, A.V. Bogatsky Physical-Chemical Institute NAS of Ukraine, Odessa 65080 (Ukraine); Fourches, Denis [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Strickland, Judy; Kleinstreuer, Nicole [ILS/Contractor Supporting the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), P.O. Box 13501, Research Triangle Park, NC 27709 (United States); Andrade, Carolina H. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Tropsha, Alexander, E-mail: alex_tropsha@unc.edu [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States)

    2015-04-15

    Repetitive exposure to a chemical agent can induce an immune reaction in inherently susceptible individuals that leads to skin sensitization. Although many chemicals have been reported as skin sensitizers, there have been very few rigorously validated QSAR models with defined applicability domains (AD) that were developed using a large group of chemically diverse compounds. In this study, we have aimed to compile, curate, and integrate the largest publicly available dataset related to chemically-induced skin sensitization, use this data to generate rigorously validated and QSAR models for skin sensitization, and employ these models as a virtual screening tool for identifying putative sensitizers among environmental chemicals. We followed best practices for model building and validation implemented with our predictive QSAR workflow using Random Forest modeling technique in combination with SiRMS and Dragon descriptors. The Correct Classification Rate (CCR) for QSAR models discriminating sensitizers from non-sensitizers was 71–88% when evaluated on several external validation sets, within a broad AD, with positive (for sensitizers) and negative (for non-sensitizers) predicted rates of 85% and 79% respectively. When compared to the skin sensitization module included in the OECD QSAR Toolbox as well as to the skin sensitization model in publicly available VEGA software, our models showed a significantly higher prediction accuracy for the same sets of external compounds as evaluated by Positive Predicted Rate, Negative Predicted Rate, and CCR. These models were applied to identify putative chemical hazards in the Scorecard database of possible skin or sense organ toxicants as primary candidates for experimental validation. - Highlights: • It was compiled the largest publicly-available skin sensitization dataset. • Predictive QSAR models were developed for skin sensitization. • Developed models have higher prediction accuracy than OECD QSAR Toolbox. • Putative

  9. Decision trees for evaluating skin and respiratory sensitizing potential of chemicals in accordance with European regulations.

    Science.gov (United States)

    Selgrade, Maryjane K; Sullivan, Katherine S; Boyles, Rebecca R; Dederick, Elizabeth; Serex, Tessa L; Loveless, Scott E

    2012-08-01

    Guidance for determining the sensitizing potential of chemicals is available in EC Regulation No. 1272/2008 Classification, Labeling, and Packaging of Substances; REACH guidance from the European Chemicals Agency; and the United Nations Globally Harmonized System (GHS). We created decision trees for evaluating potential skin and respiratory sensitizers. Our approach (1) brings all the regulatory information into one brief document, providing a step-by-step method to evaluate evidence that individual chemicals or mixtures have sensitizing potential; (2) provides an efficient, uniform approach that promotes consistency when evaluations are done by different reviewers; (3) provides a standard way to convey the rationale and information used to classify chemicals. We applied this approach to more than 50 chemicals distributed among 11 evaluators with varying expertise. Evaluators found the decision trees easy to use and recipients (product stewards) of the analyses found that the resulting documentation was consistent across users and met their regulatory needs. Our approach allows for transparency, process management (e.g., documentation, change management, version control), as well as consistency in chemical hazard assessment for REACH, EC Regulation No. 1272/2008 Classification, Labeling, and Packaging of Substances and the GHS. PMID:22584521

  10. The critical review of methodologies and approaches to assess the inherent skin sensitization potential (skin allergies) of chemicals. Part I

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Giménez-Arnau, Elena; Lepoittevin, Jean-Pierre;

    2012-01-01

    To critically review currently available methods, or methods under development (in vivo, in vitro, in silico, etc.) used in the evaluation of skin sensitization potential and their applicability in the derivation of quantitative 'safety thresholds'.......To critically review currently available methods, or methods under development (in vivo, in vitro, in silico, etc.) used in the evaluation of skin sensitization potential and their applicability in the derivation of quantitative 'safety thresholds'....

  11. Pathophysiological Study of Sensitive Skin.

    Science.gov (United States)

    Buhé, Virginie; Vié, Katell; Guéré, Christelle; Natalizio, Audrey; Lhéritier, Céline; Le Gall-Ianotto, Christelle; Huet, Flavien; Talagas, Matthieu; Lebonvallet, Nicolas; Marcorelles, Pascale; Carré, Jean-Luc; Misery, Laurent

    2016-03-01

    Sensitive skin is a clinical syndrome characterized by the occurrence of unpleasant sensations, such as pruritus, burning or pain, in response to various factors, including skincare products, water, cold, heat, or other physical and/or chemical factors. Although these symptoms suggest inflammation and the activation of peripheral innervation, the pathophysiogeny of sensitive skin remains unknown. We systematically analysed cutaneous biopsies from 50 healthy women with non-sensitive or sensitive skin and demonstrated that the intraepidermal nerve fibre density, especially that of peptidergic C-fibres, was lower in the sensitive skin group. These fibres are involved in pain, itching and temperature perception, and their degeneration may promote allodynia and similar symptoms. These results suggest that the pathophysiology of skin sensitivity resembles that of neuropathic pruritus within the context of small fibre neuropathy, and that environmental factors may alter skin innervation.

  12. Pathophysiological Study of Sensitive Skin.

    Science.gov (United States)

    Buhé, Virginie; Vié, Katell; Guéré, Christelle; Natalizio, Audrey; Lhéritier, Céline; Le Gall-Ianotto, Christelle; Huet, Flavien; Talagas, Matthieu; Lebonvallet, Nicolas; Marcorelles, Pascale; Carré, Jean-Luc; Misery, Laurent

    2016-03-01

    Sensitive skin is a clinical syndrome characterized by the occurrence of unpleasant sensations, such as pruritus, burning or pain, in response to various factors, including skincare products, water, cold, heat, or other physical and/or chemical factors. Although these symptoms suggest inflammation and the activation of peripheral innervation, the pathophysiogeny of sensitive skin remains unknown. We systematically analysed cutaneous biopsies from 50 healthy women with non-sensitive or sensitive skin and demonstrated that the intraepidermal nerve fibre density, especially that of peptidergic C-fibres, was lower in the sensitive skin group. These fibres are involved in pain, itching and temperature perception, and their degeneration may promote allodynia and similar symptoms. These results suggest that the pathophysiology of skin sensitivity resembles that of neuropathic pruritus within the context of small fibre neuropathy, and that environmental factors may alter skin innervation. PMID:26337000

  13. Hypnosis as sole anaesthesia for skin tumour removal in a patient with multiple chemical sensitivity.

    Science.gov (United States)

    Facco, E; Pasquali, S; Zanette, G; Casiglia, E

    2013-09-01

    A female patient with multiple chemical sensitivity and previous anaphylactoid reactions to local anaesthetics was admitted for removal of a thigh skin tumour under hypnosis as sole anaesthesia. The hypnotic protocol included hypnotic focused analgesia and a pre-operative pain threshold test. After inducing hypnosis, a wide excision was performed, preserving the deep fascia, and the tumour was removed; the patient's heart rate and blood pressure did not increase during the procedure. When the patient was de-hypnotised, she reported no pain and was discharged immediately. Our case confirms the efficacy of hypnosis and demonstrates that it may be valuable as a sole anaesthetic method in selected cases. Hypnosis can prevent pain perception and surgical stress as a whole, comparing well with anaesthetic drugs.

  14. Hypnosis as sole anaesthesia for skin tumour removal in a patient with multiple chemical sensitivity.

    Science.gov (United States)

    Facco, E; Pasquali, S; Zanette, G; Casiglia, E

    2013-09-01

    A female patient with multiple chemical sensitivity and previous anaphylactoid reactions to local anaesthetics was admitted for removal of a thigh skin tumour under hypnosis as sole anaesthesia. The hypnotic protocol included hypnotic focused analgesia and a pre-operative pain threshold test. After inducing hypnosis, a wide excision was performed, preserving the deep fascia, and the tumour was removed; the patient's heart rate and blood pressure did not increase during the procedure. When the patient was de-hypnotised, she reported no pain and was discharged immediately. Our case confirms the efficacy of hypnosis and demonstrates that it may be valuable as a sole anaesthetic method in selected cases. Hypnosis can prevent pain perception and surgical stress as a whole, comparing well with anaesthetic drugs. PMID:23845031

  15. A dataset on 145 chemicals tested in alternative assays for skin sensitization undergoing prevalidation.

    Science.gov (United States)

    Natsch, Andreas; Ryan, Cindy A; Foertsch, Leslie; Emter, Roger; Jaworska, Joanna; Gerberick, Frank; Kern, Petra

    2013-11-01

    Skin sensitization is a key endpoint for cosmetic ingredients, with a forthcoming ban for animal testing in Europe. Four alternative tests have so far been submitted to ECVAM prevalidation: (i) MUSST and (ii) h-Clat assess surface markers on dendritic cell lines, (iii) the direct peptide reactivity assay (DPRA) measures reactivity with model peptides and (iv) the KeratinoSens(TM) assay which is based on detection of Nrf2-induced luciferase. It is anticipated that only an integrated testing strategy (ITS) based on a battery of tests might give a full replacement providing also a sensitization potency assessment, but this concept should be tested with a data-driven analysis. Here we report a database on 145 chemicals reporting the quantitative endpoints measured in a U937- test, the DPRA and KeratinoSens(TM) . It can serve to develop data-driven ITS approaches as we show in a parallel paper and provides a view as to the current ability to predict with in vitro tests as we are entering 2013. It may also serve as reference database when benchmarking new molecules with in vitro based read-across and find use as a reference database when evaluating new tests. The tests and combinations thereof were evaluated for predictivity, and overall a similar predictivity was found as before on three-fold smaller datasets. Analysis of the dose-response parameters of the individual tests indicates a correlation to sensitization potency. Detailed analysis of chemicals false-negative and false-positive in two tests helped to define limitations in the tests but also in the database derived from animal studies. PMID:23576290

  16. Allergic skin inflammation induced by chemical sensitizers is controlled by the transcription factor Nrf2.

    Science.gov (United States)

    El Ali, Zeina; Gerbeix, Cédric; Hemon, Patrice; Esser, Philipp R; Martin, Stefan F; Pallardy, Marc; Kerdine-Römer, Saadia

    2013-07-01

    Allergic contact dermatitis (ACD) is induced by low-molecular weight electrophilic chemicals and metal ions. Chemical contact sensitizers trigger reactive oxygen species production and provoke electrophilic stress, leading to the accumulation of the transcription factor nuclear-related factor 2 (Nrf2) in innate immune cell types. The objective of this work was to identify the role of Nrf2 in the regulation of ACD. We used the local lymph node assay (LLNA) and the mouse ear swelling test (MEST) to study the role of Nrf2 in both the sensitization and elicitation phase in nrf2 knockout (nrf2(-/-)) and wild-type (nrf2(+/+)) mice. Five chemicals were used: two compounds known to react with cysteine residues, 2,4-dinitrochlorobenzene (DNCB) and cinnamaldehyde (CinA); one sensitizer known to exhibit mixed reactivity to cysteine and lysine residues, isophorone diisocyanate; and one reacting specifically with lysine residues, trimellitic anhydride and croton oil, a well-known irritant. In the MEST assay, DNCB (1 and 2%) induced a significant increase in ear thickness in nrf2(-/-) compared with nrf2(+/+) mice, suggesting a role for Nrf2 in the control of the inflammatory process. When DNCB was used at 0.25 and 0.5% or when mice were treated with CinA, inflammation was found only in nrf2(-/-) mice. In the LLNA, all chemical sensitizers induced an increase of lymphocyte proliferation in nrf2(-/-) compared with nrf2(+/+) mice for the same chemical concentration. These results reveal an important role for Nrf2 in controlling ACD and lymphocyte proliferation in response to sensitizers. PMID:23564646

  17. Evaluation of a high-throughput peptide reactivity format assay for assessment of the skin sensitization potential of chemicals

    Directory of Open Access Journals (Sweden)

    Chin Lin eWong

    2016-03-01

    Full Text Available The direct peptide reactivity assay (DPRA is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium and high concentrations and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme and non-sensitizers with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF, cysteine- (Ac-RFAACAA and lysine- (Ac-RFAAKAA containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7% and glass (47.3% vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2,4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further

  18. The critical review of methodologies and approaches to assess the inherent skin sensitization potential (skin allergies) of chemicals. Part II

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Giménez-Arnau, Elena; Lepoittevin, Jean-Pierre;

    2012-01-01

    To identify specific cases, classes or specific use situations of chemicals for which 'safety thresholds' or 'safety limits' were set (in regulations, standards, in scientific research/clinical work, etc.) and critically review the scientific and methodological parameters used to set those limits....

  19. Infrared sensing based sensitive skin

    Institute of Scientific and Technical Information of China (English)

    CAO Zheng-cai; FU Yi-li; WANG Shu-guo; JIN Bao

    2006-01-01

    Developed robotics sensitive skin is a modularized, flexible, mini-type array of infrared sensors with data processing capabilities, which can be used to cover the body of a robot. Depending on the infrared sensors and periphery processing circuit, robotics sensitive skin can in real-time provide existence and distance information about obstacles for robots within sensory areas. The methodology of designing sensitive skin and the algorithm of a mass of IR data fusion are presented. The experimental results show that the multi-joint robot with this sensitive skin can work autonomously in an unknown environment.

  20. Evaluation of the skin sensitizing potency of chemicals by using the existing methods and considerations of relevance for elicitation

    DEFF Research Database (Denmark)

    Basketter, David A; Andersen, Klaus E; Liden, Carola;

    2005-01-01

    The Technical Committee of Classification and Labelling dealing with harmonized classification of substances and classification criteria under Directive 67/548/EEC on behalf of the European Commission nominated an expert group on skin sensitization in order to investigate further the possibility...... for potency consideration of skin sensitizers for future development of the classification criteria. All substances and preparations should be classified on the basis of their intrinsic properties and should be labelled accordingly with the rules set up in the Directive 67/548/EEC. The classification should...

  1. Role of oxidative stress in ERK and p38 MAPK activation induced by the chemical sensitizer DNFB in a fetal skin dendritic cell line

    OpenAIRE

    Matos, MT; Duarte, CB; Gonçalo, Margarida; Lopes, MC

    2005-01-01

    The intracellular mechanisms involved in the early phase of dendritic cell (DC) activation upon contact with chemical sensitizers are not well known. The strong skin sensitizer 2,4-dinitrofluorobenzene (DNFB) was shown to induce the activation of mitogen-activated protein kinases (MAPK) in DC. In the present study, we investigated a putative role for oxidative stress in DNFB-induced MAPK activation and upregulation of the costimulatory molecule CD40. In a DC line generated from fetal mouse sk...

  2. An in vitro human skin test for assessing sensitization potential.

    Science.gov (United States)

    Ahmed, S S; Wang, X N; Fielding, M; Kerry, A; Dickinson, I; Munuswamy, R; Kimber, I; Dickinson, A M

    2016-05-01

    Sensitization to chemicals resulting in an allergy is an important health issue. The current gold-standard method for identification and characterization of skin-sensitizing chemicals was the mouse local lymph node assay (LLNA). However, for a number of reasons there has been an increasing imperative to develop alternative approaches to hazard identification that do not require the use of animals. Here we describe a human in-vitro skin explant test for identification of sensitization hazards and the assessment of relative skin sensitizing potency. This method measures histological damage in human skin as a readout of the immune response induced by the test material. Using this approach we have measured responses to 44 chemicals including skin sensitizers, pre/pro-haptens, respiratory sensitizers, non-sensitizing chemicals (including skin-irritants) and previously misclassified compounds. Based on comparisons with the LLNA, the skin explant test gave 95% specificity, 95% sensitivity, 95% concordance with a correlation coefficient of 0.9. The same specificity and sensitivity were achieved for comparison of results with published human sensitization data with a correlation coefficient of 0.91. The test also successfully identified nickel sulphate as a human skin sensitizer, which was misclassified as negative in the LLNA. In addition, sensitizers and non-sensitizers identified as positive or negative by the skin explant test have induced high/low T cell proliferation and IFNγ production, respectively. Collectively, the data suggests the human in-vitro skin explant test could provide the basis for a novel approach for characterization of the sensitizing activity as a first step in the risk assessment process. PMID:26251951

  3. Multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Tran, Marie Thi Dao; Arendt-Nielsen, Lars; Kupers, Ron;

    2013-01-01

    BACKGROUND: Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by recurrent, non-specific symptoms in response to chemically unrelated exposures in non-toxic concentrations. Although the pathophysiology of MCS remains unknown, central sensitization may be an important factor...

  4. In Chemico Evaluation of Tea Tree Essential Oils as Skin Sensitizers: Impact of the Chemical Composition on Aging and Generation of Reactive Species.

    Science.gov (United States)

    Avonto, Cristina; Chittiboyina, Amar G; Wang, Mei; Vasquez, Yelkaira; Rua, Diego; Khan, Ikhlas A

    2016-07-18

    Tea tree oil (TTO) is an essential oil obtained from the leaves of Melaleuca alternifolia, M. linariifolia, or M. dissitiflora. Because of the commercial importance of TTO, substitution or adulteration with other tea tree species (such as cajeput, niaouli, manuka, or kanuka oils) is common and may pose significant risks along with perceived health benefits. The distinctive nature, qualitative and quantitative compositional variation of these oils, is responsible for the various pharmacological as well as adverse effects. Authentic TTOs (especially aged ones) have been identified as potential skin sensitizers, while reports of adverse allergic reactions to the other tea trees essential oils are less frequent. Chemical sensitizers are usually electrophilic compounds, and in chemico methods have been developed to identify skin allergens in terms of their ability to bind to biological nucleophiles. However, little information is available on the assessment of sensitization potential of mixtures, such as essential oils, due to their complexity. In the present study, 10 "tea tree" oils and six major TTO constituents have been investigated for their sensitization potential using a fluorescence in chemico method. The reactivity of authentic TTOs was found to correlate with the age of the oils, while the majority of nonauthentic TTOs were less reactive, even after aging. Further thio-trapping experiments with DCYA and characterization by UHPLC-DAD-MS led to the identification of several possible DCYA-adducts which can be used to deduce the structure of the candidate reactive species. The major TTO components, terpinolene, α-terpinene, and terpinene-4-ol, were unstable under accelerated aging conditions, which led to the formation of several DCYA-adducts. PMID:27286037

  5. Skin sensitization: Modeling based on skin metabolism simulation and formation of protein conjugates

    DEFF Research Database (Denmark)

    Dimitrov, Sabcho; Low, Lawrence; Patlewicz, Grace;

    2005-01-01

    A quantitative structure-activity relationship (QSAR) system for estimating skin sensitization potency has been developed that incorporates skin metabolism and considers the potential of parent chemicals and/or their activated metabolites to react with skin proteins. A training set of diverse...... interactions of chemicals and their metabolites with skin proteins were described by 83 reactions that fall within 39 alerting groups. The SAR/QSAR system developed was able to correctly classify about 80% of the chemicals with significant sensitizing effect and 72% of nonsensitizing chemicals. For some...... alerting groups, three-dimensional (3D)-QSARs were developed to describe the multiplicity of physicochemical, steric, and electronic parameters. These 3D-QSARs, so-called pattern recognition-type models, were applied each time a latent alerting group was identified in a parent chemical or its generated...

  6. Integrated Decision Strategies for Skin Sensitization Hazard

    Science.gov (United States)

    One of the top priorities of the Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) is the identification and evaluation of non-animal alternatives for skin sensitization testing. Although skin sensitization is a complex process, the key biologi...

  7. A case of advanced mycosis fungoides with comprehensive skin and visceral organs metastasis:sensitive to chemical and biological therapy

    Institute of Scientific and Technical Information of China (English)

    Yi-Qian Liu; Wei-You Zhu; Yong-Qian Shu; Yan-Hong Gu

    2012-01-01

    Mycosis fungoides is a common cutaneousT-cell lymphoma, which is usually characterized by chronic, indolence progression, with absence of typical symptoms in early stage, metastasis to lymph nodes, bone marrow and visceral organs in later stage and ultimately progression to systemic lymphoma. It can result in secondary skin infection which is a frequent cause of death. At present, no curative therapy existed. Therapeutic purpose is to induce remission, reduce tumor burden and protect immune function of patients. A case of patient with advanced severe mycosis fungoides receivingCHOP plus interferon α-2a was reported here, with disease-free survival of 7 months and overall survival of over17.0 months, and current status as well as developments of mycosis fungoides were briefly introduced.

  8. A case of advanced mycosis fungoides with comprehensive skin and visceral organs metastasis: sensitive to chemical and biological therapy.

    Science.gov (United States)

    Liu, Yi-Qian; Zhu, Wei-You; Shu, Yong-Qian; Gu, Yan-Hong

    2012-08-01

    Mycosis fungoides is a common cutaneous T-cell lymphoma, which is usually characterized by chronic, indolence progression, with absence of typical symptoms in early stage, metastasis to lymph nodes, bone marrow and visceral organs in later stage and ultimately progression to systemic lymphoma. It can result in secondary skin infection which is a frequent cause of death. At present, no curative therapy existed. Therapeutic purpose is to induce remission, reduce tumor burden and protect immune function of patients. A case of patient with advanced severe mycosis fungoides receiving CHOP plus interferon α-2a was reported here, with disease-free survival of 7 months and overall survival of over 17.0 months, and current status as well as developments of mycosis fungoides were briefly introduced.

  9. Multiple Chemical Sensitivity

    DEFF Research Database (Denmark)

    Junge, Anne Gram

    Et voksende antal mennesker i Danmark oplever at være overfølsomme over for dufte og kemikalier. Imidlertid er den tilskrevne diagnose Multiple Chemical Sensitivity (MCS) ikke medicinsk anerkendt i Danmark pga. mangel på organiske og patofysiologisk basis for symptomerne. Dette speciale bygger på...

  10. A fluorescence high throughput screening method for the detection of reactive electrophiles as potential skin sensitizers

    Science.gov (United States)

    Skin sensitization is an important toxicological end-point in the risk assessment of chemical allergens. Because of the complexity of the biological mechanisms associated with skin sensitization integrated approaches combining different chemical, biological and in silico methods are recommended to r...

  11. Integrated decision strategies for skin sensitization hazard.

    Science.gov (United States)

    Strickland, Judy; Zang, Qingda; Kleinstreuer, Nicole; Paris, Michael; Lehmann, David M; Choksi, Neepa; Matheson, Joanna; Jacobs, Abigail; Lowit, Anna; Allen, David; Casey, Warren

    2016-09-01

    One of the top priorities of the Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) is the identification and evaluation of non-animal alternatives for skin sensitization testing. Although skin sensitization is a complex process, the key biological events of the process have been well characterized in an adverse outcome pathway (AOP) proposed by the Organisation for Economic Co-operation and Development (OECD). Accordingly, ICCVAM is working to develop integrated decision strategies based on the AOP using in vitro, in chemico and in silico information. Data were compiled for 120 substances tested in the murine local lymph node assay (LLNA), direct peptide reactivity assay (DPRA), human cell line activation test (h-CLAT) and KeratinoSens assay. Data for six physicochemical properties, which may affect skin penetration, were also collected, and skin sensitization read-across predictions were performed using OECD QSAR Toolbox. All data were combined into a variety of potential integrated decision strategies to predict LLNA outcomes using a training set of 94 substances and an external test set of 26 substances. Fifty-four models were built using multiple combinations of machine learning approaches and predictor variables. The seven models with the highest accuracy (89-96% for the test set and 96-99% for the training set) for predicting LLNA outcomes used a support vector machine (SVM) approach with different combinations of predictor variables. The performance statistics of the SVM models were higher than any of the non-animal tests alone and higher than simple test battery approaches using these methods. These data suggest that computational approaches are promising tools to effectively integrate data sources to identify potential skin sensitizers without animal testing. Published 2016. This article has been contributed to by US Government employees and their work is in the public domain in the USA. PMID:26851134

  12. Non-animal test methods for predicting skin sensitization potentials.

    Science.gov (United States)

    Mehling, Annette; Eriksson, Tove; Eltze, Tobias; Kolle, Susanne; Ramirez, Tzutzuy; Teubner, Wera; van Ravenzwaay, Bennard; Landsiedel, Robert

    2012-08-01

    Contact allergies are complex diseases, and it is estimated that 15-20 % of the general population suffers from contact allergy, with increasing prevalence. Evaluation of the sensitization potential of a substance is usually carried out in animal models. Nowadays, there is much interest in reducing and ultimately replacing current animal tests. Furthermore, as of 2013, the EU has posed a ban on animal testing of cosmetic ingredients that includes skin sensitization. Therefore, predictive and robust in vitro tests are urgently needed. In order to establish alternatives to animal testing, the in vitro tests must mimic the very complex interactions between the sensitizing chemical and the different parts of the immune system. This review article summarizes recent efforts to develop in vitro tests for predicting skin sensitizers. Cell-based assays, in chemico methods and, to a lesser extent, in silico methods are presented together with a discussion of their current status. With considerable progress having been achieved during the last years, the rationale today is that data from different non-animal test methods will have to be combined in order to obtain reliable hazard and potency information on potential skin sensitizers. PMID:22707154

  13. Mass-sensitive chemical preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Adkins, Douglas R.; Lewis, Patrick R.

    2007-01-30

    A microfabricated mass-sensitive chemical preconcentrator actively measures the mass of a sample on an acoustic microbalance during the collection process. The microbalance comprises a chemically sensitive interface for collecting the sample thereon and an acoustic-based physical transducer that provides an electrical output that is proportional to the mass of the collected sample. The acoustic microbalance preferably comprises a pivot plate resonator. A resistive heating element can be disposed on the chemically sensitive interface to rapidly heat and release the collected sample for further analysis. Therefore, the mass-sensitive chemical preconcentrator can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  14. Sensitive skin and stratum corneum reactivity to household cleaning products.

    Science.gov (United States)

    Goffin, V; Piérard-Franchimont, C; Piérard, G E

    1996-02-01

    Products intended for individuals with sensitive skin are being increasingly developed by formulators of household cleaning products. However, there is currently no consensus about the definition and recognition of the biological basis of sensitive skin. We sought to determine the relation between the nature of environmental threat perceived as aggressive by panelists, and the stratum corneum reactivity to household cleaning products as measured by the corneosurfametry test. Results indicate substantial differences in irritancy potential between proprietary products. Corneosurfametry data show significant differences in stratum corneum reactivity between, on the one hand, individuals with either non-sensitive skin or skin sensitive to climate/fabrics, and, on the other hand, individuals with detergent-sensitive skin. It is concluded that sensitive skin is not one single condition. Sound information in rating detergent-sensitive skin may be gained by corneosurfametry.

  15. Evaluating a Skin Sensitization Model and Examining Common Assumptions of Skin Sensitizers (QSAR conference)

    Science.gov (United States)

    Skin sensitization is an adverse outcome that has been well studied over many decades. Knowledge of the mechanism of action was recently summarized using the Adverse Outcome Pathway (AOP) framework as part of the OECD work programme (OECD, 2012). Currently there is a strong focus...

  16. Evaluating a Skin Sensitization Model and Examining Common Assumptions of Skin Sensitizers (ASCCT meeting)

    Science.gov (United States)

    Skin sensitization is an adverse outcome that has been well studied over many decades. It was summarized using the adverse outcome pathway (AOP) framework as part of the OECD work programme (OECD, 2012). Currently there is a strong focus on how AOPs can be applied for different r...

  17. Mechanisms of multiple chemical sensitivity.

    Science.gov (United States)

    Winder, Chris

    2002-03-10

    Sensitivity to chemicals is a toxicological concept, contained in the dose-response relationship. Sensitivity also includes the concept of hypersensitivity, although controversy surrounds the nature of effects from very low exposures. The term multiple chemical sensitivity has been used to describe individuals with a debilitating, multi-organ sensitivity following chemical exposures. Many aspects of this condition extend the nature of sensitivity to low levels of exposure to chemicals, and is a designation with medical, immunological, neuropsychological and toxicological perspectives. The basis of MCS is still to be identified, although a large number of hypersensitivity, immunological, psychological, neurological and toxicological mechanisms have been suggested, including: allergy; autosuggestion; cacosomia; conditioned response; immunological; impairment of biochemical pathways involved in energy production; impairment of neurochemical pathways; illness belief system; limbic kindling; olfactory threshold sensitivity; panic disorder; psychosomatic condition; malingering; neurogenic inflammation; overload of biotransformation pathways (also linked with free radical production); psychological or psychiatric illness; airway reactivity; sensitisation of the neurological system; time dependent sensitisation, toxicant induced loss of tolerance. Most of these theories tend to break down into concepts involving: (1) disruption in immunological/allergy processes; (2) alteration in nervous system function; (3) changes in biochemical or biotransformation capacity; (4) changes in psychological/neurobehavioural function. Research into the possible mechanisms of MCS is far from complete. However, a number of promising avenues of investigation indicate that the possibility of alteration of the sensitivity of nervous system cells (neurogenic inflammation, limbic kindling, cacosomia, neurogenic switching) are a possible mechanism for MCS.

  18. Proteomic allergen-peptide/protein interaction assay for the identification of human skin sensitizers

    NARCIS (Netherlands)

    Dietz, L.; Kinzebach, S.; Ohnesorge, S.; Franke, B.; Goette, I.; Koenig-Gressel, D.; Thierse, H.J.

    2013-01-01

    Modification of proteins by skin sensitizers is a pivotal step in T cell mediated allergic contact dermatitis (ACD). In this process small reactive chemicals interact covalently or non-covalently with cellular or extracellular skin self-proteins or self-peptides to become recognized by the human imm

  19. Prognostic value of asymptomatic skin sensitization to aeroallergens

    DEFF Research Database (Denmark)

    Bødtger, Uffe

    2004-01-01

    immunological mechanisms in asymptomatic skin sensitization might provide new insights into the natural history and treatment of respiratory allergy. RECENT FINDINGS: Research on asymptomatic skin sensitization is rare, and the present review unites previous studies with recent findings. It is a common...... positive skin test must be ruled out before allergen avoidance measures are initiated. SUMMARY: Surprisingly few papers exist on asymptomatic skin sensitization epidemiology and immunology, despite the intriguing question as to why symptoms do not develop in IgE-sensitized patients. It is a common...

  20. Multivariate Models for Prediction of Human Skin Sensitization Hazard

    Science.gov (United States)

    One of ICCVAM’s top priorities is the development and evaluation of non-animal approaches to identify potential skin sensitizers. The complexity of biological events necessary for a substance to elicit a skin sensitization reaction suggests that no single alternative method...

  1. Multivariate Models for Prediction of Skin Sensitization Hazard in Humans

    Science.gov (United States)

    One of ICCVAM’s highest priorities is the development and evaluation of non-animal approaches to identify potential skin sensitizers. The complexity of biological events necessary for a substance to elicit a skin sensitization reaction suggests that no single alternative me...

  2. Machine Learning Approaches for Predicting Human Skin Sensitization Hazard

    Science.gov (United States)

    One of ICCVAM’s top priorities is the development and evaluation of non-animal approaches to identify potential skin sensitizers. The complexity of biological events necessary for a substance to elicit a skin sensitization reaction suggests that no single in chemico, in vit...

  3. Multistage chemical carcinogenesis in mouse skin

    Energy Technology Data Exchange (ETDEWEB)

    Slaga, T.J.; Fischer, S.M.; Weeks, C.E.; Klein-Szanto, A.J.P.

    1979-01-01

    Skin tumors in mice can be induced by the sequential application of a subthreshold dose of a carcinogen (initiation phase) followed by repetitive treatment with a noncarcinogenic tumor promoter. The initiation phase requires only a single application of either a direct acting carcinogen or a procarcinogen which has to be metabolized before being active and is essentially an irreversible step which probably involves a somatic cell mutation. There is a good correlation between the skin tumor initiating activites of several polycyclic aromatic hydrocarbons (PAH) and their ability to bind covalently to epidermal DNA. Laboratory results suggest that bay region diol-epoxides are the ultimate carcinogenic form of PAH carcinogens. Potent inhibitors and stimulators of PAH tumor initiation appear to affect the level of the PAH diol-epoxide reacting with specific DNA bases. Reecent data suggests that the tumor promotion stage involves at least three important steps: (1) the induction of embryonic looking cells (dark cells) in adult epidermis; (2) an increased production of epidermal prostaglandins and polyamines; (3) sustained proliferation of dark cells. Retinoic acid specifically inhibits step two whereas the anti-inflammatory steriod fluocinolone acetonide is a potent inhibitor of steps one and three. The mechanism and the importance of a specific sequence for each step in chemical carcinogenesis in mouse skin are detailed.

  4. Determinants of skin sensitivity to solar irradiation

    NARCIS (Netherlands)

    Broekmans, W.M.R.; Vink, A.A.; Boelsma, E.; Klöpping-Ketelaars, W.A.A.; Tijburg, L.B.M.; Veer, P. van 't; Poppel, G. van; Kardinaal, A.F.M.

    2003-01-01

    Background: Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer. Objective: Our objective was to quantitatively assess phenotypical

  5. Chemical applicability domain of the Local Lymph Node Assay (LLNA) for skin sensitisation potency. Part 3. Apparent discrepancies between LLNA and GPMT sensitisation potential: False positives or differences in sensitivity?

    Science.gov (United States)

    Roberts, David W; Schultz, Terry W; Api, Anne Marie

    2016-10-01

    The Local Lymph Node Assay (LLNA) is the gold standard regulatory toxicology test for skin sensitisation along with the guinea pig maximisation test (GPMT). Compared with the GPMT, LLNA uses fewer animals, it is quantitative, and it gives a numerical prediction of potency. However several concerns have been raised with this assay, mainly related to false positives and false negatives. Over the years, many authors, including the developers of the assay, have presented cases where there have been discrepancies between the GMPT and LLNA results. Several theories have been put forward for these discrepancies, the main one being the "over-sensitivity" of the GPMT. This paper analyses the data from a systematic study, published in three papers from 2008 to 2011, covering several classes of chemicals, in particular unsaturated fatty acids, sugar surfactants and ethoxylated alcohols, with many cases of chemicals testing positive in the LLNA being negative in the GPMT. Based on consideration of reaction chemistry and structural alerts, it is concluded that these discrepancies are not LLNA false positives, but can be rationalised in terms of the different protocols of the assays. PMID:27477089

  6. Dendritic cells and skin sensitization: Biological roles and uses in hazard identification

    International Nuclear Information System (INIS)

    Recent advances have been made in our understanding of the roles played by cutaneous dendritic cells (DCs) in the induction of contact allergy. A number of associated changes in epidermal Langerhans cell phenotype and function required for effective skin sensitization are providing the foundations for the development of cellular assays (using DC and DC-like cells) for skin sensitization hazard identification. These alternative approaches to the identification and characterization of skin sensitizing chemicals were the focus of a Workshop entitled 'Dendritic Cells and Skin Sensitization: Biological Roles and Uses in Hazard Identification' that was given at the annual Society of Toxicology meeting held March 6-9, 2006 in San Diego, California. This paper reports information that was presented during the Workshop

  7. A cell-based in vitro alternative to identify skin sensitizers by gene expression

    International Nuclear Information System (INIS)

    The ethical and economic burden associated with animal testing for assessment of skin sensitization has triggered intensive research effort towards development and validation of alternative methods. In addition, new legislation on the registration and use of cosmetics and chemicals promote the use of suitable alternatives for hazard assessment. Our previous studies demonstrated that human CD34+ progenitor-derived dendritic cells from cord blood express specific gene profiles upon exposure to low molecular weight sensitizing chemicals. This paper presents a classification model based on this cell type which is successful in discriminating sensitizing chemicals from non-sensitizing chemicals based on transcriptome analysis of 13 genes. Expression profiles of a set of 10 sensitizers and 11 non-sensitizers were analyzed by RT-PCR using 9 different exposure conditions and a total of 73 donor samples. Based on these data a predictive dichotomous classifier for skin sensitizers has been constructed, which is referred to as . In a first step the dimensionality of the input data was reduced by selectively rejecting a number of exposure conditions and genes. Next, the generalization of a linear classifier was evaluated by a cross-validation which resulted in a prediction performance with a concordance of 89%, a specificity of 97% and a sensitivity of 82%. These results show that the present model may be a useful human in vitro alternative for further use in a test strategy towards the reduction of animal use for skin sensitization

  8. Functionality and specificity of gene markers for skin sensitization in dendritic cells

    OpenAIRE

    Lambrechts, Nathalie; Nelissen, Inge; van Tendeloo, Viggo; Witters, Hilda; Den Heuvel, Rosette; Hooyberghs, Jef; Schoeters, Greet

    2011-01-01

    Transcriptomic analyses revealed a discriminating gene expression profile in human CD34(+) progenitor-derived dendritic cells (DC) after exposure to skin sensitizers versus non-sensitizers. Starting from the differential expression in a small set of genes, a preliminary classification model (VITOSENS (R)) has been developed to identify chemicals as (non-)sensitizing. The objective of the current study is to gain knowledge on the role of the VITOSENS (R) markers in the DC maturation process, a...

  9. Prediction of Skin Sensitization with a Particle Swarm Optimized Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Chenzhong Cao

    2009-07-01

    Full Text Available Skin sensitization is the most commonly reported occupational illness, causing much suffering to a wide range of people. Identification and labeling of environmental allergens is urgently required to protect people from skin sensitization. The guinea pig maximization test (GPMT and murine local lymph node assay (LLNA are the two most important in vivo models for identification of skin sensitizers. In order to reduce the number of animal tests, quantitative structure-activity relationships (QSARs are strongly encouraged in the assessment of skin sensitization of chemicals. This paper has investigated the skin sensitization potential of 162 compounds with LLNA results and 92 compounds with GPMT results using a support vector machine. A particle swarm optimization algorithm was implemented for feature selection from a large number of molecular descriptors calculated by Dragon. For the LLNA data set, the classification accuracies are 95.37% and 88.89% for the training and the test sets, respectively. For the GPMT data set, the classification accuracies are 91.80% and 90.32% for the training and the test sets, respectively. The classification performances were greatly improved compared to those reported in the literature, indicating that the support vector machine optimized by particle swarm in this paper is competent for the identification of skin sensitizers.

  10. In silico risk assessment for skin sensitization using artificial neural network analysis.

    Science.gov (United States)

    Tsujita-Inoue, Kyoko; Atobe, Tomomi; Hirota, Morihiko; Ashikaga, Takao; Kouzuki, Hirokazu

    2015-04-01

    The sensitizing potential of chemicals is usually identified and characterized using in vivo methods such as the murine local lymph node assay (LLNA). Due to regulatory constraints and ethical concerns, alternatives to animal testing are needed to predict the skin sensitization potential of chemicals. For this purpose, an integrated evaluation system employing multiple in vitro and in silico parameters that reflect different aspects of the sensitization process seems promising. We previously reported that LLNA thresholds could be well predicted by using an artificial neural network (ANN) model, designated iSENS ver. 2 (integrating in vitro sensitization tests version 2), to analyze data obtained from in vitro tests focused on different aspects of skin sensitization. Here, we examined whether LLNA thresholds could be predicted by ANN using in silico-calculated descriptors of the three-dimensional structures of chemicals. We obtained a good correlation between predicted LLNA thresholds and reported values. Furthermore, combining the results of the in vitro (iSENS ver. 2) and in silico models reduced the number of chemicals for which the potency category was under-estimated. In conclusion, the ANN model using in silico parameters was shown to be have useful predictive performance. Further, our results indicate that the combination of this model with a predictive model using in vitro data represents a promising approach for integrated risk assessment of skin sensitization potential of chemicals.

  11. In silico risk assessment for skin sensitization using artificial neural network analysis.

    Science.gov (United States)

    Tsujita-Inoue, Kyoko; Atobe, Tomomi; Hirota, Morihiko; Ashikaga, Takao; Kouzuki, Hirokazu

    2015-04-01

    The sensitizing potential of chemicals is usually identified and characterized using in vivo methods such as the murine local lymph node assay (LLNA). Due to regulatory constraints and ethical concerns, alternatives to animal testing are needed to predict the skin sensitization potential of chemicals. For this purpose, an integrated evaluation system employing multiple in vitro and in silico parameters that reflect different aspects of the sensitization process seems promising. We previously reported that LLNA thresholds could be well predicted by using an artificial neural network (ANN) model, designated iSENS ver. 2 (integrating in vitro sensitization tests version 2), to analyze data obtained from in vitro tests focused on different aspects of skin sensitization. Here, we examined whether LLNA thresholds could be predicted by ANN using in silico-calculated descriptors of the three-dimensional structures of chemicals. We obtained a good correlation between predicted LLNA thresholds and reported values. Furthermore, combining the results of the in vitro (iSENS ver. 2) and in silico models reduced the number of chemicals for which the potency category was under-estimated. In conclusion, the ANN model using in silico parameters was shown to be have useful predictive performance. Further, our results indicate that the combination of this model with a predictive model using in vitro data represents a promising approach for integrated risk assessment of skin sensitization potential of chemicals. PMID:25786524

  12. Performance of a novel keratinocyte-based reporter cell line to screen skin sensitizers in vitro

    International Nuclear Information System (INIS)

    In vitro tests are needed to replace animal tests to screen for the skin sensitization potential of chemicals. Skin sensitizers are electrophilic molecules and the Nrf2-electrophile-sensing pathway comprising the repressor protein Keap1, the transcription factor Nrf2 and the antioxidant response element (ARE) is emerging as a toxicity pathway induced by skin sensitizers. Previously, we screened a large set of chemicals in the reporter cell line AREc32, which contains an eight-fold repeat of the rat GSTA2 ARE-sequence upstream of a luciferase reporter gene in the human breast cancer cell line MCF7. This approach was now further developed to bring it closer to the conditions in the human skin and to propose a fully standardized assay. To this end, a luciferase reporter gene under control of a single copy of the ARE-element of the human AKR1C2 gene was stably inserted into HaCaT keratinocytes. A standard operating procedure was developed whereby chemicals are routinely tested at 12 concentrations in triplicate for significant induction of gene activity. We report results from this novel assay on (i) a list of reference chemicals published by ECVAM, (ii) the ICCVAM list of chemicals for validation of alternative endpoints in the LLNA and (iii) on a more general list of 67 chemicals derived from the ICCVAM database. For comparison, peptide reactivity data are presented for the same chemicals. The results indicate a good predictive value of this approach for hazard identification. Its technical simplicity, the high-throughput format and the good predictivity may make this assay a candidate for rapid validation to meet the tight deadline to replace animal tests for skin sensitization by 2013 set by the European authorities.

  13. Integrated Computational Solution for Predicting Skin Sensitization Potential of Molecules

    OpenAIRE

    Konda Leela Sarath Kumar; Tangadpalliwar, Sujit R.; Aarti Desai; Vivek K Singh; Abhay Jere

    2016-01-01

    Introduction Skin sensitization forms a major toxicological endpoint for dermatology and cosmetic products. Recent ban on animal testing for cosmetics demands for alternative methods. We developed an integrated computational solution (SkinSense) that offers a robust solution and addresses the limitations of existing computational tools i.e. high false positive rate and/or limited coverage. Results The key components of our solution include: QSAR models selected from a combinatorial set, simil...

  14. A new ten-item questionnaire for assessing sensitive skin: the Sensitive Scale-10.

    Science.gov (United States)

    Misery, Laurent; Jean-Decoster, Catherine; Mery, Sophie; Georgescu, Victor; Sibaud, Vincent

    2014-11-01

    Sensitive skin is common but until now there has been no scale for measuring its severity. The Sensitive Scale is a new scale with a 14-item and a 10-item version that was tested in 11 countries in different languages on 2,966 participants. The aim of this study was to validate the pertinence of using the Sensitive Scale to measure the severity of sensitive skin. The internal consistency was high. Correlations with the dry skin type, higher age, female gender, fair phototypes and Dermatology Life Quality Index were found. Using the 10-item version appeared to be preferable because it was quicker and easier to complete, with the same internal consistency and the 4 items that were excluded were very rarely observed in patients. The mean initial scores were around 44/140 and 37/100. The use of a cream for sensitive skin showed the pertinence of the scale before and after treatment.

  15. Prediction of skin sensitizers using alternative methods to animal experimentation.

    Science.gov (United States)

    Johansson, Henrik; Lindstedt, Malin

    2014-07-01

    Regulatory frameworks within the European Union demand that chemical substances are investigated for their ability to induce sensitization, an adverse health effect caused by the human immune system in response to chemical exposure. A recent ban on the use of animal tests within the cosmetics industry has led to an urgent need for alternative animal-free test methods that can be used for assessment of chemical sensitizers. To date, no such alternative assay has yet completed formal validation. However, a number of assays are in development and the understanding of the biological mechanisms of chemical sensitization has greatly increased during the last decade. In this MiniReview, we aim to summarize and give our view on the recent progress of method development for alternative assessment of chemical sensitizers. We propose that integrated testing strategies should comprise complementary assays, providing measurements of a wide range of mechanistic events, to perform well-educated risk assessments based on weight of evidence. PMID:24548737

  16. Integrated Computational Solution for Predicting Skin Sensitization Potential of Molecules.

    Directory of Open Access Journals (Sweden)

    Konda Leela Sarath Kumar

    Full Text Available Skin sensitization forms a major toxicological endpoint for dermatology and cosmetic products. Recent ban on animal testing for cosmetics demands for alternative methods. We developed an integrated computational solution (SkinSense that offers a robust solution and addresses the limitations of existing computational tools i.e. high false positive rate and/or limited coverage.The key components of our solution include: QSAR models selected from a combinatorial set, similarity information and literature-derived sub-structure patterns of known skin protein reactive groups. Its prediction performance on a challenge set of molecules showed accuracy = 75.32%, CCR = 74.36%, sensitivity = 70.00% and specificity = 78.72%, which is better than several existing tools including VEGA (accuracy = 45.00% and CCR = 54.17% with 'High' reliability scoring, DEREK (accuracy = 72.73% and CCR = 71.44% and TOPKAT (accuracy = 60.00% and CCR = 61.67%. Although, TIMES-SS showed higher predictive power (accuracy = 90.00% and CCR = 92.86%, the coverage was very low (only 10 out of 77 molecules were predicted reliably.Owing to improved prediction performance and coverage, our solution can serve as a useful expert system towards Integrated Approaches to Testing and Assessment for skin sensitization. It would be invaluable to cosmetic/ dermatology industry for pre-screening their molecules, and reducing time, cost and animal testing.

  17. Integrated Computational Solution for Predicting Skin Sensitization Potential of Molecules

    Science.gov (United States)

    Desai, Aarti; Singh, Vivek K.; Jere, Abhay

    2016-01-01

    Introduction Skin sensitization forms a major toxicological endpoint for dermatology and cosmetic products. Recent ban on animal testing for cosmetics demands for alternative methods. We developed an integrated computational solution (SkinSense) that offers a robust solution and addresses the limitations of existing computational tools i.e. high false positive rate and/or limited coverage. Results The key components of our solution include: QSAR models selected from a combinatorial set, similarity information and literature-derived sub-structure patterns of known skin protein reactive groups. Its prediction performance on a challenge set of molecules showed accuracy = 75.32%, CCR = 74.36%, sensitivity = 70.00% and specificity = 78.72%, which is better than several existing tools including VEGA (accuracy = 45.00% and CCR = 54.17% with ‘High’ reliability scoring), DEREK (accuracy = 72.73% and CCR = 71.44%) and TOPKAT (accuracy = 60.00% and CCR = 61.67%). Although, TIMES-SS showed higher predictive power (accuracy = 90.00% and CCR = 92.86%), the coverage was very low (only 10 out of 77 molecules were predicted reliably). Conclusions Owing to improved prediction performance and coverage, our solution can serve as a useful expert system towards Integrated Approaches to Testing and Assessment for skin sensitization. It would be invaluable to cosmetic/ dermatology industry for pre-screening their molecules, and reducing time, cost and animal testing. PMID:27271321

  18. Chemically induced skin carcinogenesis: Updates in experimental models (Review).

    Science.gov (United States)

    Neagu, Monica; Caruntu, Constantin; Constantin, Carolina; Boda, Daniel; Zurac, Sabina; Spandidos, Demetrios A; Tsatsakis, Aristidis M

    2016-05-01

    Skin cancer is one of the most common malignancies affecting humans worldwide, and its incidence is rapidly increasing. The study of skin carcinogenesis is of major interest for both scientific research and clinical practice and the use of in vivo systems may facilitate the investigation of early alterations in the skin and of the mechanisms involved, and may also lead to the development of novel therapeutic strategies for skin cancer. This review outlines several aspects regarding the skin toxicity testing domain in mouse models of chemically induced skin carcinogenesis. There are important strain differences in view of the histological type, development and clinical evolution of the skin tumor, differences reported decades ago and confirmed by our hands‑on experience. Using mouse models in preclinical testing is important due to the fact that, at the molecular level, common mechanisms with human cutaneous tumorigenesis are depicted. These animal models resemble human skin cancer development, in that genetic changes caused by carcinogens and pro‑inflammatory cytokines, and simultaneous inflammation sustained by pro‑inflammatory cytokines and chemokines favor tumor progression. Drugs and environmental conditions can be tested using these animal models. keeping in mind the differences between human and rodent skin physiology. PMID:26986013

  19. CYTOKINE PROFILING FOR CHEMICAL RESPIRATORY SENSITIZERS

    Science.gov (United States)

    CYTOKINE PROFILING FOR CHEMICAL RESPIRATORY SENSITIZERS. LM Plitnick1, SE Loveless2, GS Ladics2, MP Holsapple3, MJ Selgrade4, DM Sailstad4 & RJ Smialowicz4. 1UNC, Chapel Hill, NC; 2DuPont Co., Haskell Laboratory, Newark, DE; 3Dow Chemical, Midland, MI & 4USEPA, NHEERL, RTP, NC.

  20. The pilosebaceous unit—a phthalate-induced pathway to skin sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Simonsson, Carl, E-mail: carl.simonsson@chem.gu.se [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96, Gothenburg (Sweden); Stenfeldt, Anna-Lena; Karlberg, Ann-Therese [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96, Gothenburg (Sweden); Ericson, Marica B., E-mail: marica.ericson@physics.gu.se [Department of Physics, University of Gothenburg, SE-412 96, Gothenburg (Sweden); Jonsson, Charlotte A.M. [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96, Gothenburg (Sweden)

    2012-10-01

    Allergic contact dermatitis (ACD) is caused by low-molecular weight compounds called haptens. It has been shown that the potency of haptens can depend on the formulation in which they are applied on the skin. Specifically the sensitization potency of isothiocyanates, a group of haptens which can be released from e.g. adhesive tapes and neoprene materials, increases with the presence of phthalates; however, the underlying mechanisms are not clear. A better understanding of the mechanisms governing the potency of haptens is important, e.g. to improve the risk assessment and the formulation of chemicals in consumer products. In this study we have explored phthalate-induced effects on the sensitization potency, skin distribution, and reactivity of fluorescent model isothiocyanate haptens using non-invasive two-photon microscopy to provide new insights regarding vehicle effects in ACD. The data presented in this paper indicate that the sensitization potency of isothiocyanates increases when applied in combination with dibutylphthalate due to a specific uptake via the pilosebaceous units. The results highlight the importance of shunt pathways when evaluating the bioavailability of skin sensitizers. The findings also indicate that vehicle-dependent hapten reactivity towards stratum corneum proteins regulates the bioavailability, and thus the potency, of skin sensitizers. -- Highlights: ► Vehicle effects on sensitization potency were investigated in the LLNA. ► In vivo cutaneous absorption of contact sensitizers was visualized using TPM. ► Sensitizing potency of isothiocyanates depends on the presence of a phthalate. ► Phthalate induced cutaneous absorption via the pilosebaceous units. ► Vehicle-dependent reactivity regulates sensitization potency.

  1. Chemical Decontamination of Campylobacter jejuni on Chicken Skin and Meat

    DEFF Research Database (Denmark)

    Riedel, Charlotte Tandrup; Brøndsted, Lone; Rosenquist, Hanne;

    2009-01-01

    This study evaluated the effectiveness of 11 chemical compounds to reduce Campylobacter jejuni on chicken skin and meat samples dipped in chemical solutions. Treatment of skin samples for 1 min using tartaric acid (2%) and caprylic acid sodium salt (5%) caused reductions of C. jejuni NCTC11168......, which were not significantly different from the reduction obtained by sterile water (0.95 log). Statistically larger reductions (1.57 to 3.81 log) were caused by formic acid (2%), lactic acid (2.5%), trisodium phosphate (10%), capric acid sodium salt (5%), grapefruit seed extract (1......, sterile water and lactic acid caused considerably larger reductions on skin than on meat, whereas the opposite was seen for caprylic acid sodium salt. In conclusion, this study has identified chemicals with substantial reduction effects on C. jejuni. The analysis has further emphasized that treatment time...

  2. Chemical Decontamination of Campylobacter jejuni on Chicken Skin and Meat

    DEFF Research Database (Denmark)

    Riedel, Charlotte Tandrup; Brøndsted, Lone; Rosenquist, Hanne;

    2009-01-01

    This study evaluated the effectiveness of 11 chemical compounds to reduce Campylobacter jejuni on chicken skin and meat samples dipped in chemical solutions. Treatment of skin samples for 1 min using tartaric acid (2%) and caprylic acid sodium salt (5%) caused reductions of C. jejuni NCTC11168...... chlorhexidine diacetate salt hydrate (1%). The most effective compounds were cetylpyridinium chloride (0.5%) and benzalkonium chloride (1%) (>4.2 log). However, when these treated samples were stored for 24 h at 5°C, cetylpyridinium chloride, benzalkonium chloride, and grapefruit seed extract were less...... effective, indicating that some cells may recover after a 1-min treatment with these chemicals. An increase in treatment time to 15 min resulted in higher effectiveness of trisodium phosphate and formic acid. Interestingly, when reduction of the C. jejuni population was compared on chicken skin and meat...

  3. Attenuated noradrenergic sensitivity during local cooling in aged human skin

    Science.gov (United States)

    Thompson, Caitlin S; Holowatz, Lacy A; Kenney, W. Larry

    2005-01-01

    Reflex-mediated cutaneous vasoconstriction (VC) is impaired in older humans; however, it is unclear whether this blunted VC also occurs during local cooling, which mediates VC through different mechanisms. We tested the hypothesis that the sensitization of cutaneous vessels to noradrenaline (NA) during direct skin cooling seen in young skin is blunted in aged skin. In 11 young (18–30 years) and 11 older (62–76 years) men and women, skin blood flow was monitored at two forearm sites with laser Doppler (LD) flowmetry while local skin temperature was cooled and clamped at 24°C. Cutaneous vascular conductance (CVC; LD flux/mean arterial pressure) was expressed as percentage change from baseline (%ΔCVCbase). At one site, five doses of NA (10−10–10−2m) were sequentially infused via intradermal microdialysis during cooling while the other 24°C site served as control (Ringer solution + cooling). At control sites, VC due to cooling alone was similar in young versus older (−54 ± 5 versus −56 ± 3%ΔCVCbase, P= 0.46). In young, NA infusions induced additional dose-dependent VC (10−8, 10−6, 10−4 and 10−2m: −70 ± 2, −72 ± 3, −78 ± 3 and −79 ± 4%ΔCVCbase; P older skin does not display enhanced VC capacity until treated with saturating doses of NA, possibly due to age-associated decrements in Ca2+ availability or α2C-adrenoceptor function. PMID:15705648

  4. Development of a multiparametric in vitro model of skin sensitization.

    Science.gov (United States)

    Guyard-Nicodème, Muriel; Gerault, Eloise; Platteel, Marion; Peschard, Olivier; Veron, Wilfried; Mondon, Philippe; Pascal, Svinareff; Feuilloley, Marc G J

    2015-01-01

    Most animal experiments on cosmetics safety are prohibited and since March 2013, this obligation includes sensitization tests. However, until now there has been no validated alternative in vitro method. In this work, 400 compounds used in the cosmetic industry were selected to cover the greatest diversity of structures, biological activities and sensitizing potential. These molecules were submitted to a series of tests aimed at reproducing essential steps in sensitization and to distinguish between sensitization and irritations, i.e., transcutaneous permeation (factor A), haptenation (factor B), sensitization cytokines production (factor C) and acute toxicity (factor D). The transcutaneous diffusion was measured on human skin explants using Franz cells. Haptenation was tested in solution on human serum albumin. Sensitization cytokine production was investigated by measurement of interleukin-18 release by keratinocytes. Acute toxicity was determined using an 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(75) cell viability test. As only sufficiently stable, soluble and detectable compounds are usable, 33, 72, 68 and 68 molecules were finally tested on factors A, B, C and D, respectively, and 32 were completely screened by the four factors. The individual correlation of the four factors with the reference in vivo tests was limited but the combination of these factors led to a correlation between in vivo and in vitro assays of 81.2% and the safety of the test (risk of false negative) reached 96.8%. The techniques employed are simple and inexpensive and this model of four tests appears as a promising technique to evaluate in vitro the skin sensitization potential of unknown molecules. PMID:24496914

  5. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

    Kolstad, Henrik A; Silberschmidt, Martin; Nielsen, Jesper Bo;

    2006-01-01

    Some people react to smells or chemicals at levels far below toxicological thresholds with nonspecific symptoms, fear and social isolation. They may be diagnosed with multiple chemical sensitivity. There is no empirical evidence indicating that this condition is explained by toxicological...... mechanisms, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained...... in appropriate confrontation with the chemicals encountered in everyday life....

  6. Multiple chemical sensitivity, en veldefineret lidelse?

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Silberschmidt, Martin; Nielsen, Jesper Bo;

    2006-01-01

    Some peope react to smells or chemicals at levels far below toxicological thresholds with nonspecific symptoms, fear and social isolation. They may be diagnosed with multiple chemical sensitivity. There is no empirical evidence indicating that this condition is explained by toxicological mechanisms......, even though a number of theories have been proposed. The authors of this review conclude that this is a functional condition. These patients need information and treatment in accordance with this fact. Instead of being advised how to avoid exposure to chemicals, they should be properly trained...... in appropriate confrontation with the chemicals encountered in everyday life....

  7. In Situ Metabolism of Cinnamyl Alcohol in Reconstructed Human Epidermis: New Insights into the Activation of This Fragrance Skin Sensitizer.

    Science.gov (United States)

    Moss, Eric; Debeuckelaere, Camille; Berl, Valérie; Elbayed, Karim; Moussallieh, François-Marie; Namer, Izzie-Jacques; Lepoittevin, J-P

    2016-07-18

    Chemical modification of epidermal proteins by skin sensitizers is the molecular event which initiates the induction of contact allergy. However, not all chemical skin allergens react directly as haptens with epidermal proteins but need either a chemical (prehaptens) or metabolic (prohaptens) activation step to become reactive. Cinnamyl alcohol has been considered a model prohapten, as this skin sensitizer has no intrinsic reactivity. Therefore, the prevailing theory is that cinnamyl alcohol is enzymatically oxidized into the protein-reactive cinnamaldehyde, which is the sensitizing agent. Knowing that reconstructed human epidermis (RHE) models have been demonstrated to be quite similar to the normal human epidermis in terms of metabolic enzymes, use of RHE may be useful to investigate the in situ metabolism/activation of cinnamyl alcohol, particularly when coupled with high-resolution magic angle spinning nuclear magnetic resonance. Incubation of carbon-13 substituted cinnamyl derivatives with RHE did not result in the formation of cinnamaldehyde. The metabolites formed suggest the formation of an epoxy-alcohol and an allylic sulfate as potential electrophiles. These data suggest that cinnamyl alcohol is inducing skin sensitization through a route independent of the one involving cinnamaldehyde and should therefore be considered as a skin sensitizer on its own. PMID:27281158

  8. Contact sensitizers induce skin inflammation via ROS production and hyaluronic acid degradation.

    Directory of Open Access Journals (Sweden)

    Philipp R Esser

    Full Text Available BACKGROUND: Allergic contact dermatitis (ACD represents a severe health problem with increasing worldwide prevalence. It is a T cell-mediated skin disease induced by protein-reactive organic and inorganic chemicals. A key feature of contact allergens is their ability to trigger an innate immune response that leads to skin inflammation. Previous evidence from the mouse contact hypersensitivity (CHS model suggests a role for endogenous activators of innate immune signaling. Here, we analyzed the role of contact sensitizer induced ROS production and concomitant changes in hyaluronic acid metabolism on CHS responses. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed in vitro and in vivo ROS production using fluorescent ROS detection reagents. HA fragmentation was determined by gel electrophoresis. The influence of blocking ROS production and HA degradation by antioxidants, hyaluronidase-inhibitor or p38 MAPK inhibitor was analyzed in the murine CHS model. Here, we demonstrate that organic contact sensitizers induce production of reactive oxygen species (ROS and a concomitant breakdown of the extracellular matrix (ECM component hyaluronic acid (HA to pro-inflammatory low molecular weight fragments in the skin. Importantly, inhibition of either ROS-mediated or enzymatic HA breakdown prevents sensitization as well as elicitation of CHS. CONCLUSIONS/SIGNIFICANCE: These data identify an indirect mechanism of contact sensitizer induced innate inflammatory signaling involving the breakdown of the ECM and generation of endogenous danger signals. Our findings suggest a beneficial role for anti-oxidants and hyaluronidase inhibitors in prevention and treatment of ACD.

  9. Sensitive Chemical Compass Assisted by Quantum Criticality

    CERN Document Server

    Cai, C Y; Quan, H T; Sun, C P

    2011-01-01

    The radical-pair-based chemical reaction could be used by birds for the navigation via the geomagnetic direction. An inherent physical mechanism is that the quantum coherent transition from a singlet state to triplet states of the radical pair could response to the weak magnetic field and be sensitive to the direction of such a field and then results in different photopigments in the avian eyes to be sensed. Here, we propose a quantum bionic setup for the ultra-sensitive probe of a weak magnetic field based on the quantum phase transition of the environments of the two electrons in the radical pair. We prove that the yield of the chemical products via the recombination from the singlet state is determined by the Loschmidt echo of the environments with interacting nuclear spins. Thus quantum criticality of environments could enhance the sensitivity of the detection of the weak magnetic field.

  10. Chemical feedbacks in climate sensitivity studies

    Science.gov (United States)

    Dietmüller, Simone; Ponater, Michael; Sausen, Robert

    2013-04-01

    Interactively coupled climate chemistry models extend the number of feedback mechanisms in climate change simulations by allowing a variation of several radiatively actice chemical tracers that are prescribed in conventional climate models. Different perturbation experiments including chemical feedbacks were performed using the chemistry-climate model system EMAC coupled to the mixed layer ocean model MLO. The influence of the chemical feedbacks O3, CH4 and N2O on climate response and climate sensitivity is quantified for a series of CO2-perturbation simulations: Equilibrium climate sensitivity is dampened, if chemical feedbacks are included. In case of a CO2 doubling simulation chemical feedbacks decrease climate sensitivity by -3.6% and in case of a 4*CO2 simulation by -8.1%. Analysis of the chemical feedbacks reveals, that the negative feedback of ozone, mainly the feedback of stratospheric ozone, is responsible for this dampening. The radiative feedbacks of CH4 and N2O are negligible, mainly because the model system does not allow interactive emission feedbacks at the Earth's surface for these gases. The feedback of physical parameters is significantly modified by the presence of chemical feedbacks. In case of the CO2-perturbation experiments the negative stratospheric ozone feedback is accompanied by a negative stratospheric H2O feedback change of the same order of magnitude. So the dampening effect of the direct O3 radiative feedback is enhanced. A non-linearity in the damping is found with increasing CO2 concentrations. Reasons are the nonlinear feedbacks of ozone, temperature, and stratospheric water vapor. Additional 6*CO2 simulations with and without chemical feedbacks included show, that the presence of chemic feedbacks helps to prevent a runaway greenhouse effect, as the O3 distribution can react to the upward shift of the tropopause. Also experiments driven by anthropogenic NOx- and CO-emissions were performed, where chemically active trace gases act

  11. Skin Sensitive Difference of Human Body Sections under Clothing-Smirnov Test of Skin Surface Temperatures' Dynamic Changing

    Institute of Scientific and Technical Information of China (English)

    LI Jun; WU Hai-yan; WANG Yun-yi

    2004-01-01

    Skin sensitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design.By a new method of researching on clothing comfort perception,the skin temperature live changing procedure of human body sections affected by the same cold stimulation is inspected.Furthermore with the Smirnov test the skin temperatures dynamic changing patterns of main human body sections are obtained.

  12. Sensitive chemical compass assisted by quantum criticality

    Science.gov (United States)

    Cai, C. Y.; Ai, Qing; Quan, H. T.; Sun, C. P.

    2012-02-01

    A radical-pair-based chemical reaction might be used by birds for navigation via the geomagnetic direction. The inherent physical mechanism is that the quantum coherent transition from a singlet state to triplet states of the radical pair could respond to a weak magnetic field and be sensitive to the direction of such a field; this then results in different photopigments to be sensed by the avian eyes. Here, we propose a quantum bionic setup, inspired by the avian compass, as an ultrasensitive probe of a weak magnetic field based on the quantum phase transition of the environments of the two electrons in the radical pair. We prove that the yield of the chemical products via recombination from the singlet state is determined by the Loschmidt echo of the environments with interacting nuclear spins. Thus quantum criticality of environments could enhance the sensitivity of detection of weak magnetic fields.

  13. Sensitivity analysis on an AC600 aluminum skin component

    Science.gov (United States)

    Mendiguren, J.; Agirre, J.; Mugarra, E.; Galdos, L.; Saenz de Argandoña, E.

    2016-08-01

    New materials are been introduced on the car body in order to reduce weight and fulfil the international CO2 emission regulations. Among them, the application of aluminum alloys is increasing for skin panels. Even if these alloys are beneficial for the car design, the manufacturing of these components become more complex. In this regard, numerical simulations have become a necessary tool for die designers. There are multiple factors affecting the accuracy of these simulations e.g. hardening, anisotropy, lubrication, elastic behavior. Numerous studies have been conducted in the last years on high strength steels component stamping and on developing new anisotropic models for aluminum cup drawings. However, the impact of the correct modelling on the latest aluminums for the manufacturing of skin panels has been not yet analyzed. In this work, first, the new AC600 aluminum alloy of JLR-Novelis is characterized for anisotropy, kinematic hardening, friction coefficient, elastic behavior. Next, a sensitivity analysis is conducted on the simulation of a U channel (with drawbeads). Then, the numerical an experimental results are correlated in terms of springback and failure. Finally, some conclusions are drawn.

  14. Multiple chemical sensitivity: a 1999 consensus.

    Science.gov (United States)

    1999-01-01

    Consensus criteria for the definition of multiple chemical sensitivity (MCS) were first identified in a 1989 multidisciplinary survey of 89 clinicians and researchers with extensive experience in, but widely differing views of, MCS. A decade later, their top 5 consensus criteria (i.e., defining MCS as [1] a chronic condition [2] with symptoms that recur reproducibly [3] in response to low levels of exposure [4] to multiple unrelated chemicals and [5] improve or resolve when incitants are removed) are still unrefuted in published literature. Along with a 6th criterion that we now propose adding (i.e., requiring that symptoms occur in multiple organ systems), these criteria are all commonly encompassed by research definitions of MCS. Nonetheless, their standardized use in clinical settings is still lacking, long overdue, and greatly needed--especially in light of government studies in the United States, United Kingdom, and Canada that revealed 2-4 times as many cases of chemical sensitivity among Gulf War veterans than undeployed controls. In addition, state health department surveys of civilians in New Mexico and California showed that 2-6%, respectively, already had been diagnosed with MCS and that 16% of the civilians reported an "unusual sensitivity" to common everyday chemicals. Given this high prevalence, as well as the 1994 consensus of the American Lung Association, American Medical Association, U.S. Environmental Protection Agency, and the U.S. Consumer Product Safety Commission that "complaints [of MCS] should not be dismissed as psychogenic, and a thorough workup is essential," we recommend that MCS be formally diagnosed--in addition to any other disorders that may be present--in all cases in which the 6 aforementioned consensus criteria are met and no single other organic disorder (e.g., mastocytosis) can account for all the signs and symptoms associated with chemical exposure. The millions of civilians and tens of thousands of Gulf War veterans who

  15. Two-tiered keratinocyte assay: IL-18 production by NCTC2544 cells to determine the skin sensitizing capacity and an epidermal equivalent assay to determine sensitizer potency

    DEFF Research Database (Denmark)

    Teunis, Marc; Corsini, Emanuela; Smits, Mieke;

    2012-01-01

    method to the LLNA. Both assays are based on the use of human keratinocytes, which have been shown, over the last two decades, to play a key role in all phases of skin sensitization. First, 4 known chemicals were tested during a transferability study in which 6 laboratories participated. Three......At present, the identification of potentially sensitizing chemicals is carried out using animal models. However, it should be very important, both from ethical and economic point of view, to discriminate allergy and irritation events, and to classify sensitizers according to their potency, without......2544 IL-18 assay can be used to identify the sensitizing capacity of a chemical (NCTC assay, tier 1) while the Epidermal Equivalent potency assay is used to quantify the potency of the sensitizing agent (EE assay, tier 2). These assays combined, may offer an unique opportunity to provide an alternative...

  16. Skin Sensitive Difference of Human Body Sections under Clothing --Comparative Judging of Body Sections' Cold Sensitivity Sequence

    Institute of Scientific and Technical Information of China (English)

    LI Jun; WANG Yun-yi; WU Hai-yan

    2005-01-01

    Skin sensitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design. By a new psychological & physical researching method, the subjective psychological perception of human body sections affected by the same cold stimulus are studied, and with Thurstone comparative judgement the main human body sections' cold sensitivity sequences are obtained. Furthermore the physiological causes for skin sensitive difference of human body sections under clothing are suggested.

  17. Discrimination of skin sensitizers from non-sensitizers by interleukin-1α and interleukin-6 production on cultured human keratinocytes.

    Science.gov (United States)

    Jung, Daun; Che, Jeong-Hwan; Lim, Kyung-Min; Chun, Young-Jin; Heo, Yong; Seok, Seung Hyeok

    2016-09-01

    In vitro testing methods for classifying sensitizers could be valuable alternatives to in vivo sensitization testing using animal models, such as the murine local lymph node assay (LLNA) and the guinea pig maximization test (GMT), but there remains a need for in vitro methods that are more accurate and simpler to distinguish skin sensitizers from non-sensitizers. Thus, the aim of our study was to establish an in vitro assay as a screening tool for detecting skin sensitizers using the human keratinocyte cell line, HaCaT. HaCaT cells were exposed to 16 relevant skin sensitizers and 6 skin non-sensitizers. The highest dose used was the dose causing 75% cell viability (CV75) that we determined by an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The levels of extracellular production of interleukin-1α (IL-1α) and IL-6 were measured. The sensitivity of IL-1α was 63%, specificity was 83% and accuracy was 68%. In the case of IL-6, sensitivity: 69%, specificity: 83% and accuracy: 73%. Thus, this study suggests that measuring extracellular production of pro-inflammatory cytokines IL-1α and IL-6 by human HaCaT cells may potentially classify skin sensitizers from non-sensitizers. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26691653

  18. Skin sensitization risk assessment model using artificial neural network analysis of data from multiple in vitro assays.

    Science.gov (United States)

    Tsujita-Inoue, Kyoko; Hirota, Morihiko; Ashikaga, Takao; Atobe, Tomomi; Kouzuki, Hirokazu; Aiba, Setsuya

    2014-06-01

    The sensitizing potential of chemicals is usually identified and characterized using in vivo methods such as the murine local lymph node assay (LLNA). Due to regulatory constraints and ethical concerns, alternatives to animal testing are needed to predict skin sensitization potential of chemicals. For this purpose, combined evaluation using multiple in vitro and in silico parameters that reflect different aspects of the sensitization process seems promising. We previously reported that LLNA thresholds could be well predicted by using an artificial neural network (ANN) model, designated iSENS ver.1 (integrating in vitro sensitization tests version 1), to analyze data obtained from two in vitro tests: the human Cell Line Activation Test (h-CLAT) and the SH test. Here, we present a more advanced ANN model, iSENS ver.2, which additionally utilizes the results of antioxidant response element (ARE) assay and the octanol-water partition coefficient (LogP, reflecting lipid solubility and skin absorption). We found a good correlation between predicted LLNA thresholds calculated by iSENS ver.2 and reported values. The predictive performance of iSENS ver.2 was superior to that of iSENS ver.1. We conclude that ANN analysis of data from multiple in vitro assays is a useful approach for risk assessment of chemicals for skin sensitization. PMID:24444449

  19. Performance of the N/TERT epidermal model for skin sensitizer identification via Nrf2-Keap1-ARE pathway activation.

    Science.gov (United States)

    Alloul-Ramdhani, Mariam; Tensen, Cornelis P; El Ghalbzouri, Abdoelwaheb

    2014-08-01

    Animal testing of chemical ingredients for cosmetic purposes is prohibited. Therefore there is an urgent need for in vitro models to identify chemical allergens. In human skin, keratinocytes (KCs) are abundantly present and are key players in initiation of allergic contact dermatitis. One of the pathways that has been shown to be induced by sensitizers is the Keap1-Nrf2-ARE pathway. In this study we compared the response of four keratinocyte-based models including (a) primary human KCs, (b) N/TERT monolayer cultures, (c) the Leiden Epidermal models (LEMs) and (d) the N/TERT epidermal models (NEMs). All keratinocyte-based models were subjected to chemical exposure of the sensitizer 2,4-dinitrochlorobenzene (DNCB) and irritant Sodium dodecyl sulfate (SDS) at nontoxic concentrations. Activation of the Keap1-Nrf2-ARE pathway was evaluated by measuring Nrf2 protein levels as well as nuclear translocation and activation of transcriptional targets of Nrf2. Results show that the Keap1-Nrf2-ARE pathway is activated by the sensitizer DNCB in monolayer keratinocytes and as well as the LEMs and NEMs and not by the irritant SDS. Collectively our data demonstrate that the N/TERT models respond similarly as primary KCs and could therefore serve as an alternative model for skin sensitizer identification, thereby overcoming the need for primary skin tissue. PMID:24794257

  20. Assessment of the sensitizing potency of low molecular weight chemicals : employment of a regression method in vivo and in vitro

    OpenAIRE

    Och, Franciscus Martinus Maria van

    2003-01-01

    One of the most important allergic diseases caused by chemicals, contact hypersensitivity (CHS) or skin sensitization, forms a serious problem for individuals experiencing such a reaction. The prevalence of CHS tends to grow proportionally to the increasing exposure to an expanding variety of chemicals. Predictive animal tests to identify sensitizing properties of chemicals are therefore carried out at a large scale. For a better risk assessment, a more quantitative assessment of the sensitiz...

  1. Simultaneous Skin Friction and Pressure Sensitive Paint Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Currently, the contribution of skin friction to the total drag of a wind tunnel model is estimated by comparing measurements of the total drag to the integrated...

  2. A genomic biomarker signature can predict skin sensitizers using a cell-based in vitro alternative to animal tests

    Directory of Open Access Journals (Sweden)

    Albrekt Ann-Sofie

    2011-08-01

    Full Text Available Abstract Background Allergic contact dermatitis is an inflammatory skin disease that affects a significant proportion of the population. This disease is caused by an adverse immune response towards chemical haptens, and leads to a substantial economic burden for society. Current test of sensitizing chemicals rely on animal experimentation. New legislations on the registration and use of chemicals within pharmaceutical and cosmetic industries have stimulated significant research efforts to develop alternative, human cell-based assays for the prediction of sensitization. The aim is to replace animal experiments with in vitro tests displaying a higher predictive power. Results We have developed a novel cell-based assay for the prediction of sensitizing chemicals. By analyzing the transcriptome of the human cell line MUTZ-3 after 24 h stimulation, using 20 different sensitizing chemicals, 20 non-sensitizing chemicals and vehicle controls, we have identified a biomarker signature of 200 genes with potent discriminatory ability. Using a Support Vector Machine for supervised classification, the prediction performance of the assay revealed an area under the ROC curve of 0.98. In addition, categorizing the chemicals according to the LLNA assay, this gene signature could also predict sensitizing potency. The identified markers are involved in biological pathways with immunological relevant functions, which can shed light on the process of human sensitization. Conclusions A gene signature predicting sensitization, using a human cell line in vitro, has been identified. This simple and robust cell-based assay has the potential to completely replace or drastically reduce the utilization of test systems based on experimental animals. Being based on human biology, the assay is proposed to be more accurate for predicting sensitization in humans, than the traditional animal-based tests.

  3. Skin irritants and contact sensitizers induce Langerhans cell migration and maturation at irritant concentration

    NARCIS (Netherlands)

    Jacobs, J.J.L.; Lehé, C.L.; Hasegawa, H.; Elliott, G.R.; Das, P.K.

    2006-01-01

    Skin irritants and contact allergens reduce the number of Langerhans cells (LCs). It has been assumed that this reduction is due their migration to the draining lymph node (LN) for initiating immune sensitization in a host. Skin irritation, however, as opposed to contact allergy is not considered to

  4. Phospholipidomic Profile Variation on THP-1 Cells Exposed to Skin or Respiratory Sensitizers and Respiratory Irritant.

    Science.gov (United States)

    Martins, João D; Maciel, Elisabete A; Silva, Ana; Ferreira, Isabel; Ricardo, Fernando; Domingues, Pedro; Neves, Bruno M; Domingues, Maria Rosário M; Cruz, Maria Teresa

    2016-12-01

    Occupational exposure to low molecular weight reactive chemicals often leads to development of allergic reactions such as allergic contact dermatitis and respiratory allergies. Further insights into the interaction of these chemicals with physiopathological relevant cellular models might provide the foundations for novel non-animal approaches to safety assessment. In this work we used the human THP-1 cell line to determine phospholipidome changes induced by the skin sensitizer 1-fluoro-2,4-dinitrobenzene (DNFB), the respiratory allergen hexamethylene diisocyanate (HDI), and the irritant methyl salicylate (MESA). We detected that these chemicals differently induce lipid peroxidation and modulate THP-1 IL-1β, IL-12B, IL-8, CD86, and HMOX1 transcription. Decreased phosphatidylethanolamine content was detected in cells exposed to MESA, while profound alterations in the relative abundance of cardiolipin species were observed in cells exposed to DNFB. All chemicals tested induced a decrease in the relative abundance of plasmanyl phosphatidylcholine species PC (O-16:0e/18:1) and phosphatidylinositol species PI (34:1), while increasing PI (38:4). An increased abundance of oleic acid was observed in the phospholipids of cells exposed to DNFB while a decreased abundance of palmitic acid was detected in cells treated with MESA or DNFB. We conclude that both specific and common alterations at phospholipidome levels are triggered by the different chemicals, while not allowing a complete distinction between them using a Canonical Analysis of Principal Coordinates (CAP). The common effects observed at phospholipids level with all the chemicals tested might be related to unspecific cell cytotoxic mechanisms that nevertheless may contribute to the elicitation of specific immune responses. J. Cell. Physiol. 231: 2639-2651, 2016. © 2016 Wiley Periodicals, Inc. PMID:26946329

  5. Contrasting effects of ultraviolet-A and ultraviolet B exposure on induction of contact sensitivity in human skin

    DEFF Research Database (Denmark)

    Skov, Lone; Hansen, Henrik; Barker, J. N.;

    1997-01-01

    model of tumour antigens. Volunteers (n = 46) were randomly assigned to received no sensitization, sensitization with the allergen diphenylcyclopropenone (DPCP) on non-UV-exposed normal skin, or sensitization with DPCP on skin exposed to three minimal erythema doses (MED) of either UVA or UVB radiation...... 3 days before sensitization. Three weeks after sensitization all volunteers were challenged with five different concentrations of DPCP. The challenge reactions were scored clinically and the increase in skin thickness was measured using a micrometer. Sensitization on UVB-exposed skin reduced the...... immunization rate compared with sensitization on non-irradiated skin (P < 0.03) as previously described. In contrast, sensitization on skin exposed to three MED UVA radiation did not result in a decreased immunization rate compared with non-irradiated skin. These results indicate that in humans erythemagenic...

  6. A skin sensitization risk assessment approach for evaluation of new ingredients and products.

    Science.gov (United States)

    Gerberick, G F; Robinson, M K

    2000-06-01

    Skin sensitization risk assessment of new ingredients or products is critical before their introduction into the marketplace. The risk assessment process described in this article involves evaluation of skin sensitization hazard, consideration of all potential human exposures, comparative ingredient/product benchmarking, and, when appropriate, the management of the risk. In this article, a risk assessment process is reviewed along with a description of the risk assessment tools that are employed for evaluating a new ingredient or product. The basic process we use for evaluating the skin sensitization risk of a new product or ingredient is considered a no effect/safety factor approach. The tools used for conducting a risk assessment include structure activity relationship analysis, exposure assessment, preclinical testing (e.g., local lymph node assay [LNNA]) and clinical testing (e.g., human repeat insult patch testing [HRIPT]). The skin sensitization risk assessment process described in this paper has been used successfully for many years for the safe introduction of new products into the marketplace. This process is dynamic--it can be applied to a diversity of product categories (e.g., shampoo, transdermal drug). In summary, the skin sensitization risk assessment process described in this article allows one to carefully assess the skin sensitization potential of a new ingredient or product so that it can be safely introduced into the marketplace.

  7. Evaluation of a Silicone Membrane as an Alternative to Human Skin for Determining Skin Permeation Parameters of Chemical Compounds.

    Science.gov (United States)

    Uchida, Takashi; Yakumaru, Masafumi; Nishioka, Keisuke; Higashi, Yoshihiro; Sano, Tomohiko; Todo, Hiroaki; Sugibayashi, Kenji

    2016-01-01

    We evaluated the effectiveness of a silicone membrane as an alternative to human skin using the skin permeation parameters of chemical compounds. An in vitro permeation study using 15 model compounds was conducted, and permeation parameters comprising permeability coefficient (P), diffusion parameter (DL(-2)), and partition parameter (KL) were calculated from each permeation profile. Significant correlations were obtained in log P, log DL(-2), and log KL values between the silicone membrane and human skin. DL(-2) values of model compounds, except flurbiprofen, in the silicone membrane were independent of the lipophilicity of the model compounds and were 100-fold higher than those in human skin. For antipyrine and caffeine, which are hydrophilic, KL values in the silicone membrane were 100-fold lower than those in human skin, and P values, calculated as the product of a DL(-2) and KL, were similar. For lipophilic compounds, such as n-butyl paraben and flurbiprofen, KL values for silicone were similar to or 10-fold higher than those in human skin, and P values for silicone were 100-fold higher than those in human skin. Furthermore, for amphiphilic compounds with log Ko/w values from 0.5 to 3.5, KL values in the silicone membrane were 10-fold lower than those in human skin, and P values for silicone were 10-fold higher than those in human skin. The silicone membrane was useful as a human skin alternative in an in vitro skin permeation study. However, depending on the lipophilicity of the model compounds, some parameters may be over- or underestimated. PMID:27581638

  8. Touch perceptions across skin sites: differences between sensitivity, direction discrimination and pleasantness

    Directory of Open Access Journals (Sweden)

    Rochelle eAckerley

    2014-02-01

    Full Text Available Human skin is innervated with different tactile afferents over the body, which are found at varying densities. We investigate how the relationships between tactile pleasantness, sensitivity and discrimination differ across the skin. Tactile pleasantness was assessed by stroking a soft brush over the skin, using five velocities (0.3, 1, 3, 10, 30 cm s-1, known to differentiate hedonic touch, and pleasantness ratings were gained. The ratings velocity-profile is known to correlate with firing in unmyelinated C-tactile afferents. Tactile sensitivity thresholds were determined using monofilament force detection and the tactile discrimination level was obtained in the direction discrimination of a moving probe; both tasks readily activate myelinated touch receptors. Perceptions were measured over five skin sites: forehead, arm, palm, thigh and shin. The assessment of tactile pleasantness over the skin resulted in a preference for the middle velocities (1-10 cm s-1, where higher ratings were gained compared to the slowest and fastest velocities. This preference in tactile pleasantness was found across all the skin sites, apart from at the palm, where no decrease in pleasantness for the faster stroking velocities was seen. We find that tactile sensitivity and discrimination vary across the skin, where the forehead and palm show increased acuity. Tactile sensitivity and discrimination levels also correlated significantly, although the tactile acuity did not relate to the perceived pleasantness of touch. Tactile pleasantness varied in a subtle way across skin sites, where the middle velocities were always rated as the most pleasant, but the ratings at hairy skin sites were more receptive to changes in stroking velocity. We postulate that although the mechanoreceptive afferent physiology may be different over the skin, the perception of pleasant touch can be interpreted using all of the available incoming somatosensory information in combination with

  9. Gene expression in the skin of dogs sensitized to the house dust mite Dermatophagoides farinae.

    Science.gov (United States)

    Schamber, Paz; Schwab-Richards, Rachel; Bauersachs, Stefan; Mueller, Ralf S

    2014-10-01

    Atopic dermatitis is a multifactorial allergic skin disease in humans and dogs. Genetic predisposition, immunologic hyperreactivity, a defective skin barrier, and environmental factors play a role in its pathogenesis. The aim of this study was to analyze gene expression in the skin of dogs sensitized to house dust mite antigens. Skin biopsy samples were collected from six sensitized and six nonsensitized Beagle dogs before and 6 hr and 24 hr after challenge using skin patches with allergen or saline as a negative control. Transcriptome analysis was performed by the use of DNA microarrays and expression of selected genes was validated by quantitative real-time RT-PCR. Expression data were compared between groups (unpaired design). After 24 hr, 597 differentially expressed genes were detected, 361 with higher and 226 with lower mRNA concentrations in allergen-treated skin of sensitized dogs compared with their saline-treated skin and compared with the control specimens. Functional annotation clustering and pathway- and co-citation analysis showed that the genes with increased expression were involved in inflammation, wound healing, and immune response. In contrast, genes with decreased expression in sensitized dogs were associated with differentiation and barrier function of the skin. Because the sensitized dogs did not show differences in the untreated skin compared with controls, inflammation after allergen patch test probably led to a decrease in the expression of genes important for barrier formation. Our results further confirm the similar pathophysiology of human and canine atopic dermatitis and revealed genes previously not known to be involved in canine atopic dermatitis.

  10. Profile of patients with chemical injury and sensitivity.

    Science.gov (United States)

    Ziem, G; McTamney, J

    1997-03-01

    Patients reporting sensitivity to multiple chemicals at levels usually tolerated by the healthy population were administered standardized questionnaires to evaluate their symptoms and the exposures that aggravated these symptoms. Many patients were referred for medical tests. It is thought that patients with chemical sensitivity have organ abnormalities involving the liver, nervous system (brain, including limbic, peripheral, autonomic), immune system, and porphyrin metabolism, probably reflecting chemical injury to these systems. Laboratory results are not consistent with a psychologic origin of chemical sensitivity. Substantial overlap between chemical sensitivity, fibromyalgia, and chronic fatigue syndrome exists: the latter two conditions often involve chemical sensitivity and may even be the same disorder. Other disorders commonly seen in chemical sensitivity patients include headache (often migraine), chronic fatigue, musculoskeletal aching, chronic respiratory inflammation (rhinitis, sinusitis, laryngitis, asthma), attention deficit, and hyperactivity (affected younger children). Less common disorders include tremor, seizures, and mitral valve prolapse. Patients with these overlapping disorders should be evaluated for chemical sensitivity and excluded from control groups in future research. Agents whose exposures are associated with symptoms and suspected of causing onset of chemical sensitivity with chronic illness include gasoline, kerosene, natural gas, pesticides (especially chlordane and chlorpyrifos), solvents, new carpet and other renovation materials, adhesives/glues, fiberglass, carbonless copy paper, fabric softener, formaldehyde and glutaraldehyde, carpet shampoos (lauryl sulfate) and other cleaning agents, isocyanates, combustion products (poorly vented gas heaters, overheated batteries), and medications (dinitrochlorobenzene for warts, intranasally packed neosynephrine, prolonged antibiotics, and general anesthesia with petrochemicals). Multiple

  11. Sensitive Diagnostics for Chemically Reacting Flows

    KAUST Repository

    Farooq, Aamir

    2015-11-02

    This talk will feature latest diagnostic developments for sensitive detection of gas temperature and important combustion species. Advanced optical strategies, such as intrapulse chirping, wavelength modulation, and cavity ringdown are employed.

  12. The vomeronasal organ and chemical sensitivity: a hypothesis.

    OpenAIRE

    Greene, Glenn J; Kipen, Howard M

    2002-01-01

    Environmental exposures to very low levels of airborne chemicals are associated with adverse symptoms, often affecting multiple organ systems, in the phenomenon of chemical sensitivity (CS). Recent surveys suggest a significant prevalence of chemically sensitive subjects in the United States, but the mechanism linking exposure to symptoms remains unclear, despite the advancement of a variety of theoretical models. In many of these models, exposure of the nasal respiratory system to an airborn...

  13. Bragg grating chemical sensor with hydrogel as sensitive element

    Institute of Scientific and Technical Information of China (English)

    Xiaomei Liu(刘小梅); Shilie Zheng(郑史烈); Xianmin Zhang(章献民); Jun Cong(丛军); Kangsheng Chen(陈抗生); Jian Xu(徐坚)

    2004-01-01

    A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hydrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor.

  14. Selective skin sensitivity changes and sensory reweighting following short-duration space flight.

    Science.gov (United States)

    Lowrey, Catherine R; Perry, Stephen D; Strzalkowski, Nicholas D J; Williams, David R; Wood, Scott J; Bent, Leah R

    2014-03-15

    Skin sensory input from the foot soles is coupled with vestibular input to facilitate body orientation in a gravitational environment. Anecdotal observations suggest that foot sole skin becomes hypersensitive following space flight. The veritable level of skin sensitivity and its impact on postural disequilibrium observed post space flight have not been documented. Skin sensitivity of astronauts (n = 11) was measured as vibration perception at the great toe, fifth metatarsal and heel. Frequencies targeted four classes of receptors: 3 and 25 Hz for slow-adapting (SA) receptors and 60 and 250 Hz for fast-adapting (FA) receptors. Data were collected pre- and post-space flight. We hypothesized that skin sensitivity would increase post-space flight and correlate to balance measures. Decreased skin sensitivity was found on landing day at 3 and 25 Hz on the great toe. Hypersensitivity was found for a subset of astronauts (n = 6) with significantly increased sensitivity to 250 Hz at the heel. This subset displayed a greater reduction in computerized dynamic posturography (CDP) equilibrium (EQ) scores (-54%) on landing vs. non-hypersensitive participants (-11%). Observed hyposensitivity of SA (pressure) receptors may indicate a strategy to reduce pressure input during periods of unloading. Hypersensitivity of FAs coupled with reduced EQ scores may reflect targeted sensory reweighting. Altered gravito-inertial environments reduce vestibular function in balance control which may trigger increased weighting of FAs (that signal foot contact, slips). Understanding modulations to skin sensitivity has translational implications for mitigating postural disequilibrium following space flight and for on-Earth preventative strategies for imbalance in older adults.

  15. A magneto-sensitive skin for robots in space

    Science.gov (United States)

    Chauhan, D. S.; Dehoff, P. H.

    1991-01-01

    The development of a robot arm proximity sensing skin that can sense intruding objects is described. The purpose of the sensor would be to prevent the robot from colliding with objects in space including human beings. Eventually a tri-mode system in envisioned including proximity, tactile, and thermal. To date the primary emphasis was on the proximity sensor which evolved from one based on magneto-inductive principles to the current design which is based on a capacitive-reflector system. The capacitive sensing element, backed by a reflector driven at the same voltage and in phase with the sensor, is used to reflect field lines away from the grounded robot toward the intruding object. This results in an increased sensing range of up to 12 in. with the reflector on compared with only 1 in. with it off. It is believed that this design advances the state-of-the-art in capacitive sensor performance.

  16. Asymptomatic skin sensitization to birch predicts later development of birch pollen allergy in adults

    DEFF Research Database (Denmark)

    Bødtger, Uffe; Poulsen, Lars K; Malling, Hans-Jørgen

    2003-01-01

    birch skin prick test weal diameter of > or =4 mm, a positive conjunctival provocation test result, and specific IgE of > or =CAP class 2, as well as with the presence of other allergies. Specific IgE of > or =CAP class 2 was 87.5% predictive for allergy development, whereas a negative conjunctival...... risk is any subject with target organ sensitivity, an elevated specific IgE level, and/or a skin prick test weal diameter of >4 mm....

  17. Contact Sensitizers Induce Skin Inflammation via ROS Production and Hyaluronic Acid Degradation

    OpenAIRE

    Esser, Philipp R.; Ute Wölfle; Christoph Dürr; Friederike D von Loewenich; Schempp, Christoph M.; Freudenberg, Marina A.; Thilo Jakob; Martin, Stefan F.

    2012-01-01

    BACKGROUND: Allergic contact dermatitis (ACD) represents a severe health problem with increasing worldwide prevalence. It is a T cell-mediated skin disease induced by protein-reactive organic and inorganic chemicals. A key feature of contact allergens is their ability to trigger an innate immune response that leads to skin inflammation. Previous evidence from the mouse contact hypersensitivity (CHS) model suggests a role for endogenous activators of innate immune signaling. Here, we analyzed ...

  18. Contact Sensitizers Induce Skin Inflammation via ROS Production and Hyaluronic Acid Degradation

    OpenAIRE

    Philipp R Esser; Wölfle, Ute; Dürr, Christoph; Friederike D von Loewenich; Schempp, Christoph M.; Freudenberg, Marina A.; Jakob, Thilo; Martin, Stefan F

    2012-01-01

    Background Allergic contact dermatitis (ACD) represents a severe health problem with increasing worldwide prevalence. It is a T cell-mediated skin disease induced by protein-reactive organic and inorganic chemicals. A key feature of contact allergens is their ability to trigger an innate immune response that leads to skin inflammation. Previous evidence from the mouse contact hypersensitivity (CHS) model suggests a role for endogenous activators of innate immune signaling. Here, we analyzed t...

  19. Sodium flux ratio through the amiloride-sensitive entry pathway in frog skin

    OpenAIRE

    1983-01-01

    The sodium flux ratio of the amiloride-sensitive Na+ channel in the apical membrane of in vitro Rana catesbeiana skin has been evaluated at different sodium concentrations and membrane potentials in sulfate Ringer solution. Amiloride-sensitive unidirectional influxes and effluxes were determined as the difference between bidirectional 22Na and 24Na fluxes simultaneously measured in the absence and presence of 10(-4) M amiloride in the external bathing solution. Amiloride- sensitive Na+ efflux...

  20. Skin.

    Science.gov (United States)

    Mancini, Anthony J

    2004-04-01

    Human skin provides a barrier between the host and the physical, chemical, and biological environment. It is also a potential portal of entry for hazardous or infectious agents and a potential target of environmental toxins. Cutaneous vulnerability may take on many forms in the embryo, infant, child, and adolescent. Teratogenic agents may occasionally target skin, as appreciated in the proposed association of the antithyroid medication methimazole, with the congenital malformation known as aplasia cutis congenita. Percutaneous absorption of topically applied substances and the potential for resultant drug toxicities are important considerations in the child. Many topical agents have been associated with systemic toxicity, including alcohol, hexachlorophene, iodine-containing compounds, eutectic mixture of local anesthetics, and lindane. Percutaneous toxicity is of greatest concern in the premature infant, in whom immaturity of the epidermal permeability barrier results in disproportionately increased absorption. Immature drug metabolism capabilities may further contribute to the increased risk in this population. Ultraviolet (UV) radiation exposure, which increases an individual's risk of cutaneous carcinogenesis, may be a particularly significant risk factor when it occurs during childhood. The "critical period hypothesis" suggests that UV exposure early in life increases the risk of eventual development of malignant melanoma. Other risk factors for malignant melanoma may include severe sunburns during childhood, intense intermittent UV exposure, and increased susceptibility of pediatric melanocytes to UV-induced DNA damage. Last, percutaneous exposure to environmental toxins and chemicals, such as insecticides and polychlorinated biphenyls, may differ between children and adults for several reasons, including behavioral patterns, anatomic and physiologic variations, and developmental differences of vital organs. PMID:15060207

  1. Chemical ultraviolet absorbers topically applied in a skin barrier mimetic formulation remain in the outer stratum corneum of porcine skin.

    Science.gov (United States)

    Haque, T; Crowther, J M; Lane, M E; Moore, D J

    2016-08-20

    The objective of the present study was to evaluate the fate of three chemical sunscreens, isoamyl p-methoxycinnamate (IPMC), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), and bis-ethylhexylphenol methoxyphenyl triazine (BEMT), topically applied to mammalian skin from a skin barrier mimetic oil-in-water formulation. High Performance Liquid Chromatography (HPLC) methods were developed for the analysis of each molecule and validated. Franz cell permeation studies were conducted following application of finite doses of the formulations to excised porcine skin. A vehicle formulation containing no sunscreens was evaluated as a control. Permeation studies were conducted for 12h after which full mass balance studies were carried out. Analysis of individual UV sunscreens was achieved with HPLC following application of the formulation to the skin with no interference from the vehicle components. No skin permeation of any of the chemical sunscreens was evident after 12h. While sunscreens were detected in up to 12 tape strips taken from the SC, 87% or more of the applied doses recovered in the first 5 tape strips. When corrected for the amount of protein removed per tape strip this corresponded to a penetration depth in porcine stratum corneum of ∼1.7μm. Mass balance studies indicated total recovery values were within accepted guidelines for cosmetic formulations. Overall, only superficial penetration into the SC was observed for each compound. These findings are consistent with the physicochemical properties of the selected UV absorbing molecules and their formulation into an ordered biomimetic barrier formulation thus support their intended use in topical consumer formulations designed to protect from UV exposure. To our knowledge this is the first report of depth profiling of chemical sunscreens in the SC that combines tape stripping and protein determination following in vitro Franz cell studies. PMID:27321112

  2. Assessment of phototoxicity, skin irritation, and sensitization potential of polystyrene and TiO2 nanoparticles

    Science.gov (United States)

    Park, Yoon-Hee; Jeong, Sang Hoon; Yi, Sang Min; Hyeok Choi, Byeong; Kim, Yu-Ri; Kim, In-Kyoung; Kim, Meyoung-Kon; Son, Sang Wook

    2011-07-01

    The human skin equivalent model (HSEM) is well known as an attractive alternative model for evaluation of dermal toxicity. However, only limited data are available on the usefulness of an HSEM for nanotoxicity testing. This study was designed to investigate cutaneous toxicity of polystyrene and TiO2 nanoparticles using cultured keratinocytes, an HSEM, and an animal model. In addition, we also evaluated the skin sensitization potential of nanoparticles using a local lymph node assay with incorporation of BrdU. Findings from the present study indicate that polystyrene and TiO2 nanoparticles do not induce phototoxicity, acute cutaneous irritation, or skin sensitization. Results from evaluation of the HSEMs correspond well with those from animal models. Our findings suggest that the HSEM might be a useful alternative model for evaluation of dermal nanotoxicity.

  3. Assessment of phototoxicity, skin irritation, and sensitization potential of polystyrene and TiO2 nanoparticles

    International Nuclear Information System (INIS)

    The human skin equivalent model (HSEM) is well known as an attractive alternative model for evaluation of dermal toxicity. However, only limited data are available on the usefulness of an HSEM for nanotoxicity testing. This study was designed to investigate cutaneous toxicity of polystyrene and TiO2 nanoparticles using cultured keratinocytes, an HSEM, and an animal model. In addition, we also evaluated the skin sensitization potential of nanoparticles using a local lymph node assay with incorporation of BrdU. Findings from the present study indicate that polystyrene and TiO2 nanoparticles do not induce phototoxicity, acute cutaneous irritation, or skin sensitization. Results from evaluation of the HSEMs correspond well with those from animal models. Our findings suggest that the HSEM might be a useful alternative model for evaluation of dermal nanotoxicity.

  4. Skin prick test results to artesunate in children sensitized to Artemisia vulgaris L.

    Science.gov (United States)

    Mori, F; Pantano, S; Rossi, M E; Montagnani, C; Chiappini, E; Novembre, E; Galli, L; de Martino, M

    2015-09-01

    Artemisia vulgaris L and Artemisia annua L (Chinese: qinghao) are similar plants of the Asterbaceae family. Artesunate, a semi-synthetic derivate of artemisin which is the active principle extract of the plant qinghao, has antimalarial properties. Some cases of severe allergic reactions to artesunate have been described. The purpose of this study was to evaluate the association between positive skin tests to Artemisia vulgaris L allergen and a preparation of injectable artesunate. A total of 531 children were skin prick tested with inhalants (including Artemisia vulgaris L), foods, and artesunate. Among the 59 patients positive to Artemisia vulgaris L only one child was also positive to artesunate. No child was positive to artesunate in those negative to Artemisia vulgaris L. We conclude that Artemisia vulgaris L sensitization is not associated with sensitization to artesunate; consequently, skin test to artesunate should not be carried out before using the drug considering the rare allergic reactions. PMID:26157064

  5. Evaluation of dermal and eye irritation and skin sensitization due to carbon nanotubes.

    Science.gov (United States)

    Ema, Makoto; Matsuda, Akitaka; Kobayashi, Norihiro; Naya, Masato; Nakanishi, Junko

    2011-12-01

    The present paper summarizes the results of our studies on dermal and eye irritation and skin sensitization due to carbon nanotubes (CNTs), whose potential applications and uses are wide and varied, including CNT-enhanced plastics, electromagnetic interference/radio-frequency (EMI/RFI) shielding, antistatic material, flexible fibers and advanced polymers, medical and health applications, and scanning probe microscopy. Skin and eyes have the highest risk of exposure to nanomaterials, because deposition of nanomaterials to the surficial organs has the potential to be a major route of exposure during the manufacturing, use, and disposal of nanomaterials. Two products composed of single-walled carbon nanotubes (SWCNTs) and two products composed of multi-walled carbon nanotubes (MWCNTs) were tested regarding acute dermal and acute eye irritation using rabbits, and skin sensitization using guinea pigs. The concentrations of the CNTs in the substances were the maximum allowable for administration. The two products of SWCNTs and one of the products of MWCNTs were not irritants to the skin or eyes. The other product of MWCNTs caused very slight erythema at 24h, but not at 72h, after patch removal in the dermal irritation experiments and conjunctival redness and blood vessel hyperemia at 1h, but not at 24h, in eye irritation experiments. These findings showed that one product of MWCNTs was a very weak acute irritant to the skin and eyes. No products of SWCNTs and MWCNTs exhibited skin-sensitization effects. Our knowledge of the toxicological effects of CNTs is still limited. Further information is needed to clarify the potential for irritation and sensitization given the complex nature of CNTs. PMID:21893152

  6. Chemically Sensitive Imaging of MgP with STM

    Science.gov (United States)

    Yu, Arthur; Li, Shaowei; Czap, Greg; Ho, Wilson

    2014-03-01

    Since its invention, the STM has been limited by its lack of sensitivity to chemical structures in molecules. Recent advances in scanning probe microscopy techniques, such as non-contact AFM and scanning tunneling hydrogen microscopy have enabled imaging of the internal structure and bonding of aromatic molecules such as pentacene and PTCDA. Here, we present a novel method of using the STM to image magnesium porphyrin molecules adsorbed on Au(110) with chemical sensitivity. In our previous study, we have shown that hydrogen molecules weakly adsorb on Au(110), exhibiting both vibrational and rotational IETS spectra. Exploiting the sensitivity of the vibrational and rotational mode energies to the local chemical environment, we perform dI/dV and d2I/dV2 imaging at different bias voltages, highlighting the various parts of the MgP molecule. In particular, we are able to image the positions of the nitrogen atoms in MgP. d2I/dV2 spectral mapping reveals that the origin of the chemical sensitivity comes from an energy shift of the rotational peak as the tip is scanned across the molecule, indicating a changing potential landscape for the H2. Similar d2I/dV2 imaging with a CO terminated tip reveals no chemical sensitivity to nitrogen.

  7. Epicutaneous Allergic Sensitization by Cooperation between Allergen Protease Activity and Mechanical Skin Barrier Damage in Mice.

    Science.gov (United States)

    Shimura, Sakiko; Takai, Toshiro; Iida, Hideo; Maruyama, Natsuko; Ochi, Hirono; Kamijo, Seiji; Nishioka, Izumi; Hara, Mutsuko; Matsuda, Akira; Saito, Hirohisa; Nakae, Susumu; Ogawa, Hideoki; Okumura, Ko; Ikeda, Shigaku

    2016-07-01

    Allergen sources such as mites, insects, fungi, and pollen contain proteases. Airway exposure to proteases induces allergic airway inflammation and IgE/IgG1 responses via IL-33-dependent mechanisms in mice. We examined the epicutaneous sensitization of mice to a model protease allergen, papain; the effects of tape stripping, which induces epidermal barrier dysfunction; and the atopic march upon a subsequent airway challenge. Papain painting on ear skin and tape stripping cooperatively promoted dermatitis, the skin gene expression of proinflammatory cytokines and growth factors, up-regulation of serum total IgE, and papain-specific IgE/IgG1 induction. Epicutaneous sensitization induced T helper (Th) 2 cells and Th17 differentiation in draining lymph nodes. Ovalbumin and protease inhibitor-treated papain induced no or weak responses, whereas the co-administration of ovalbumin and papain promoted ovalbumin-specific IgE/IgG1 induction. Wild-type and IL-33-deficient mice showed similar responses in the epicutaneous sensitization phase. The subsequent airway papain challenge induced airway eosinophilia and maintained high papain-specific IgE levels in an IL-33-dependent manner. These results suggest that allergen source-derived protease activity and mechanical barrier damage such as that caused by scratching cooperatively promote epicutaneous sensitization and skin inflammation and that IL-33 is dispensable for epicutaneous sensitization but is crucial in the atopic march upon a subsequent airway low-dose encounter with protease allergens. PMID:26987428

  8. Skin Sensitization Study of Bee Venom (Apis mellifera L.) in Guinea Pigs

    OpenAIRE

    Han, Sang Mi; Lee, Gwang Gill; Park, Kyun Kyu

    2012-01-01

    Bee venom (Apis mellifera L., BV) has been used as a cosmetic ingredient for antiaging, anti-inflammatory and antibacterial functions. The aim of this study was to access the skin sensitization of BV, a Buehler test was conducted fifty healthy male Hartley guinea pigs with three groups; Group G1 (BVsensitization group, 20 animals), group G2 (the positive control-sensitization group, 20 animals), and group G3 (the ethyl alcohol-sensitization group, 10 animals). The exposure on the left flank f...

  9. Genetic susceptibility factors for multiple chemical sensitivity revisited

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Berg; Linneberg, Allan; Andersen, Charlotte Brasch;

    2010-01-01

    Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low levels of chemical substances. Various genes, especially genes of importance to the metabolism of xenobiotic compounds, have been associated with MCS, but findings are inconsistent. The purpose of this ...... examined are of less importance to MCS than previously reported or that gene-environment interactions or significant degrees of genetic heterogeneity in MCS underlie inconsistent findings in the literature....... of this study was to investigate genetic susceptibility factors for MCS and self-reported chemical sensitivity in a population sample. Ninety six MCS patients and 1,207 controls from a general population divided into four severity groups of chemical sensitivity were genotyped for variants in the genes encoding...... compared in post hoc analyses with all individuals from the population sample (p=0.02). Genetic variants in paraoxonase 1 and methylene tetrahydrofolate reductase were not associated with MSC or with self-reported chemical sensitivity in the population sample. Our results suggest that variants in the genes...

  10. Experimental strategies for research on multiple chemical sensitivity.

    OpenAIRE

    Weiss, B.

    1997-01-01

    Skepticism about the validity of the multiple chemical sensitivity (MCS) syndrome stems in part from the lack of supporting experimental data. Performing the relevant experiments requires investigators to take account of broad variations in sensitivity and the need to establish reproducibility. The research approach best suited for MCS studies is the single-subject design. In contrast with conventional group designs, such designs emphasize repeated observations on individual subjects. Repeate...

  11. A nanofiber based artificial electronic skin with high pressure sensitivity and 3D conformability

    Science.gov (United States)

    Zhong, Weibin; Liu, Qiongzhen; Wu, Yongzhi; Wang, Yuedan; Qing, Xing; Li, Mufang; Liu, Ke; Wang, Wenwen; Wang, Dong

    2016-06-01

    Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The protuberances composed of intertwined elastic POE nanofibers and PPy@PVA-co-PE nanofibers afford a tunable effective elastic modulus that is capable of capturing varied strains and stresses, thereby contributing to a high sensitivity for pressure sensing. This electronic skin-like sensor demonstrates an ultra-high sensitivity (1.24 kPa-1) below 150 Pa with a detection limit as low as about 1.3 Pa. The pixelated sensor array and a RGB-LED light are then assembled into a circuit and show a feasibility for visual detection of spatial pressure. Furthermore, a nanofiber based proof-of-concept wireless pressure sensor with a bluetooth module as a signal transmitter is proposed and has demonstrated great promise for wireless monitoring of human physiological signals, indicating a potential for large scale wearable electronic devices or e-skin.Pressure sensors with 3D conformability are highly desirable components for artificial electronic skin or e-textiles that can mimic natural skin, especially for application in real-time monitoring of human physiological signals. Here, a nanofiber based electronic skin with ultra-high pressure sensitivity and 3D conformability is designed and built by interlocking two elastic patterned nanofibrous membranes. The patterned membrane is facilely prepared by casting conductive nanofiber ink into a silicon mould to form an array of semi-spheroid-like protuberances. The

  12. Skin sensitization--a critical review of predictive test methods in animals and man.

    Science.gov (United States)

    Botham, P A; Basketter, D A; Maurer, T; Mueller, D; Potokar, M; Bontinck, W J

    1991-04-01

    With the exception of the Draize Test, the guinea-pig test methods currently accepted by regulatory authorities worldwide are well able to predict the potential of a material to cause skin sensitization. Nevertheless, (a) some methods are more sensitive than others (e.g. adjuvant tests are generally more sensitive than non-adjuvant tests); (b) methods cannot be sufficiently standardized to give full reproducibility of results between laboratories; and (c) most methods are based on subjective visual grading of skin reactions--difficulties thus arise when testing coloured or irritant materials. Laboratories must be able to show the sensitivity of the method(s) they use by demonstrating that positive reactions occur with mild/moderate contact allergens rather than the strong/extreme sensitizers currently recommended in certain guidelines, specifically in the EEC Test Method. The sensitivity of the adjuvant tests is such that it is possible to halve the minimum number of animals required by present regulatory guidelines without compromising the capacity of the tests to detect weak/mild sensitizers. A similar review has not yet been made for non-adjuvant tests. Alternative test methods, including some recently developed mouse models, offer several advantages, including more objective endpoints. These tests have not been extensively validated and this precludes their use at present for regulatory purposes other than to confirm the sensitization potential of a material. Two new test methods using mice, the Mouse Ear-swelling Test and the Local Lymph Node Assay, appear promising. They should undergo rigorous interlaboratory testing to determine their sensitivity and specificity. In vitro methods do not represent a viable alternative in the foreseeable future. An approach using quantitative structure-activity relationships is the most likely route to a non-animal model, but this will require considerable research, development and validation. Human sensitization tests have

  13. Influence of drying temperature on the chemical constituents of jaboticaba (Plinia Jaboticaba (Vell. Berg skin

    Directory of Open Access Journals (Sweden)

    Ana Paula de C. Alves

    2014-09-01

    Full Text Available Jaboticaba is a fruit native to Brazil. Its skin represents up to 43% of the fruit and contains high levels of fiber, minerals and phenolic compounds. The use of the skin waste adds value to the fruit. However, one of the drawbacks of skin storage is the high water content, which requires drying processes to preserve the skin without leading to the loss of nutrients and antioxidants. The influence of different drying temperatures on the levels of nutrients and antioxidants was investigated. Jaboticaba (Plinia jaboticaba (Vell. Berg, genotype Sabará skins were lyophilized or dried at three temperatures (30, 45, and 60ºC, using food dryers. The skins were then ground, stored (protected from light and subjected to analysis of proximate composition, vitamin C, phytate, polyphenols, anthocyanins and antioxidant activity. The drying process had little effect on the proximate composition of the flour, presenting significant difference only for crude protein, fiber and non-nitrogenous extract. The greatest preservation of chemical constituents occurs in the lyophilized jaboticaba skins. Among the drying temperatures tested, however, the skins dried at 45 and60°C had more highly preserved nutritional substances and antioxidants.

  14. Evaluation of a topical treatment for the relief of sensitive skin

    Directory of Open Access Journals (Sweden)

    Heinicke IR

    2015-07-01

    Full Text Available Ingrid R Heinicke,1 Damian H Adams,2 Tanya M Barnes,1 Kerryn A Greive1 1Ego Pharmaceuticals, Braeside, VIC, Australia; 2Mawson Institute, University of South Australia, Mawson Lakes, SA, Australia Background: Approximately, 50% of the population claim to have sensitive skin, which has created an important challenge for dermatologists and the cosmetic industry. This study evaluates the properties of QV Face Rescue Gel (Rescue Gel that contains a combination of moisturizing and anti-irritant ingredients, and which is used to relieve the symptoms of sensitive facial skin. Methods: The ability of Rescue Gel to induce collagen types I and III in cultured neonatal human foreskin fibroblasts compared to transforming growth factor beta 1, a known potent inducer of collagen types I and III, was measured using immunofluorescence staining. Furthermore, healthy volunteers were recruited to measure the potential for Rescue Gel to reduce erythema induced by solar-simulated ultraviolet radiation on the skin compared to 0.5% hydrocortisone cream (positive control as well as it's ability to decrease transepidermal water loss compared to baseline levels. In addition, the formulation was tested for its potential to be 1 nonstinging using a facial sting/discomfort assay performed on volunteers who reacted positively to lactic acid, 2 nonirritating as determined by repeat insult patch tests, and 3 noncomedogenic. Results: Rescue Gel significantly induced collagen types I and III in cultured human foreskin fibroblasts similarly to transforming growth factor beta 1. In volunteers, Rescue Gel was shown to significantly reduce erythema induced by solar-simulated ultraviolet radiation similarly to 0.5% hydrocortisone, and to significantly reduce transepidermal water loss compared to baseline levels. Further, the formulation was found to be nonstinging, nonirritating, and noncomedogenic. No adverse events were observed. Conclusion: In this study, Rescue Gel has been shown

  15. Differential modulation of CXCR4 and CD40 protein levels by skin sensitizers and irritants in the FSDC cell line

    OpenAIRE

    Neves, Bruno Miguel; Cruz, Maria Teresa; Francisco, Vera; Gonçalo, Margarida; Figueiredo, Américo; Duarte, Carlos B.; Lopes, Maria Celeste

    2008-01-01

    The development of non-animal methods for skin sensitization testing is an urgent challenge. Some of the most promising in vitro approaches are based on the analysis of phenotypical and functional modifications induced by sensitizers in dendritic cell models. In this work, we evaluated, for the first time, a fetal skin-derived dendritic cell line (FSDC) as a model to discriminate between sensitizers and irritants, through analysis of their effects on CD40 and CXCR4 protein expression. The che...

  16. Evaluation of a topical treatment for the relief of sensitive skin

    OpenAIRE

    Heinicke IR; Adams DH; Barnes TM; Greive KA

    2015-01-01

    Ingrid R Heinicke,1 Damian H Adams,2 Tanya M Barnes,1 Kerryn A Greive1 1Ego Pharmaceuticals, Braeside, VIC, Australia; 2Mawson Institute, University of South Australia, Mawson Lakes, SA, Australia Background: Approximately, 50% of the population claim to have sensitive skin, which has created an important challenge for dermatologists and the cosmetic industry. This study evaluates the properties of QV Face Rescue Gel (Rescue Gel) that contains a combination of moisturizing and anti-irritant ...

  17. Chlorine Dioxide Induced Multiple Chemical Sensitivity: MMPI Validity Problems.

    Science.gov (United States)

    Tentoni, Stuart C.

    This paper discusses Minnesota Multiphasic Personality Inventory (MMPI) data obtained from individuals exposed to chlorine dioxide in the workplace who developed Multiple Chemical Sensitivity Syndrome. The paper explores current research on chlorine dioxide exposed persons who were misdiagnosed on the basis of MMPI interpretations. Difficulties…

  18. Potential natural sensitizers extracted from the skin of Canarium odontophyllum fruits for dye-sensitized solar cells

    Science.gov (United States)

    Lim, Andery; Kumara, N. T. R. N.; Tan, Ai Ling; Mirza, Aminul Huq; Chandrakanthi, R. L. N.; Petra, Mohammad Iskandar; Ming, Lim Chee; Senadeera, G. K. R.; Ekanayake, Piyasiri

    2015-03-01

    Possibility of use of dye extract from skin samples of a seasonal, indigenous fruit from Borneo, namely Canarium odontophyllum, in dye sensitized solar cells (DSSCs) are explored. Three main groups of flavonoid pigments are detected and these pigments exhibit different UV-vis absorption properties, and hence showing different light harvesting capabilities. When applied in DSSCs. The detected pigment constituents of the extract consist of aurone (maritimein), anthocyanidin (pelargonidin) and anthocyanidin (cyanidin derivatives). When tested in DSSC, the highest conversion efficiency of 1.43% is exhibited by cyanidin derivatives, and this is followed by conversion efficiencies of 0.51% and 0.79% for aurone and pelargonidin, respectively. It is shown that individual pigments, like cyanidin derivatives and pelargonidin, exhibit higher power conversion efficiency when compared to that of C.odontophyllum skin pigment mixture (with a conversion efficiency of only 0.68%). The results indicate a possibility of masking effects of the pigments when used as a mixture. The acidification of C.odontophyllum skin pigments with concentrated hydrochloric acid improves the conversion efficiency of the mixture from 0.68% to 0.99%. The discussion in this paper will draw data and observations from the variation in absorption and adsorption properties, the HOMO-LUMO levels, the energy band gaps and the functional group compositions of the detected flavonoids.

  19. Chemosensory perception, symptoms and autonomic responses during chemical exposure in multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Andersson, Linus; Claeson, Anna Sara; Dantoft, Thomas Meinertz;

    2016-01-01

    Purpose: Multiple chemical sensitivity (MCS) is a prevalent medically unexplained symptom characterized by symptom reactions to everyday chemical exposure below hygienic thresholds. The aim of this study was to investigate the expressions of hyper-reactivity in MCS during whole-body exposure to l...

  20. [The experimental application of chitosan membrane for treating chemical burns of the skin].

    Science.gov (United States)

    Pogorielov, M; Kalinkevich, O; Gortinskaya, E; Moskalenko, R; Tkachenko, Yu

    2014-01-01

    The basic method for skin damage treatment, including chemical wounds, is a topical application of different agents. Their objective is to repair structure of the skin and its functions. All dressings for treating wounds are classified as biological, artificial and composites containing both synthetic and natural materials. There are many studies concerning application of chitosan, which is a derivate of natural polymer chitin, as a basis for topical materials to treat burns. However, data are rather limited about application of chitosan for treating acid burns. Thus, the aim of research is to study the morphological futures of skin regeneration after the chemical burn applying chitosan membranes. We performed the experiment on 60 young rats (3 months old) with the chemical burns of third-degree (IIIA degree) to study the morphofunctional features of skin regeneration. Later we applied the chitosan membranes on the burns. We carried out a histologic investigation on the biopsy specimens of wound to determine the morphological features of wound regeneration. The results confirmed that earlier granulation and epithelialization of the skin surface happened as the chitosan membrane was applied on the acid effected surface. The final result of the application of chitosan film is to achieve full epithelialization, preserve the structure of tissues beneath the burn and prevent getting scars.

  1. Tracking thermal fronts with temperature-sensitive, chemically reactive tracers

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, B.A.; Birdsell, S.A.

    1987-01-01

    Los Alamos is developing tracer techniques using reactive chemicals to track thermal fronts in fractured geothermal reservoirs. If a nonadsorbing tracer flowing from the injection to production well chemically reacts, its reaction rate will be a strong function of temperature. Thus the extent of chemical reaction will be greatest early in the lifetime of the system, and less as the thermal front progresses from the injection to production well. Early laboratory experiments identified tracers with chemical kinetics suitable for reservoirs in the temperature range of 75 to 100/sup 0/C. Recent kinetics studies have focused on the kinetics of hydrolysis of derivatives of bromobenzene. This class of reactions can be used in reservoirs ranging in temperature from 150 to 275/sup 0/C, which is of greater interest to the geothermal industry. Future studies will include laboratory adsorption experiments to identify possibly unwanted adsorption on granite, development of sensitive analytical techniques, and a field demonstration of the reactive tracer concept.

  2. [Combination of a universal antidote and temporary skin substitute for chemical burns: Extended case report].

    Science.gov (United States)

    Liodaki, E; Schopp, B E; Lindert, J; Krämer, R; Kisch, T; Mailänder, P; Stang, F

    2015-09-01

    In this article we describe our experiences in the treatment of chemical burns with Diphoterine(®) solution and Suprathel(®) as a temporary skin substitute material, a treatment which in the past was not commonly used for this pattern of injuries. In the study period from October 2012 to December 2013 we treated five patients (four male and one female including two children and three adults) with chemical burns by decontamination with Diphoterine(®) and wound covering with Suprathel(®). The control group included five patients with similar injury patterns who were treated with Diphoterine(®) and occlusive wound dressings. No wound infections occurred in any of the five cases and no interactions were observed between Suprathel(®) and the chemical substance involved. In four cases the skin areas with IIa-IIb degree damage showed good wound healing and only slight scarring in the follow-up after 3 months and one of the five patients had to be treated surgically. Suprathel(®) can be used as a temporary skin substitute for the treatment of skin burns and is also available for the treatment of chemical burns.

  3. Mindfulness-based cognitive therapy to treat multiple chemical sensitivities

    DEFF Research Database (Denmark)

    Skovbjerg, S; Hauge, Christian Riis; Rasmussen, Alice;

    2012-01-01

    of an 8-week mindfulness-based cognitive therapy program (MBCT) for adults with MCS and to evaluate possible effects on psychological distress and illness perception. The study design was a randomized clinical trial. The MBCT programme comprised 8 weekly sessions of 2½ hours. Forty-two adults were......Multiple chemical sensitivities (MCS) is a medically unexplained and socially disabling disorder characterized by negative health effects attributed to exposure to common airborne chemicals. Currently, there is no evidence-based treatment. The objectives of the study were to assess the feasibility...

  4. Bayesian integrated testing strategy (ITS) for skin sensitization potency assessment: a decision support system for quantitative weight of evidence and adaptive testing strategy.

    Science.gov (United States)

    Jaworska, Joanna S; Natsch, Andreas; Ryan, Cindy; Strickland, Judy; Ashikaga, Takao; Miyazawa, Masaaki

    2015-12-01

    The presented Bayesian network Integrated Testing Strategy (ITS-3) for skin sensitization potency assessment is a decision support system for a risk assessor that provides quantitative weight of evidence, leading to a mechanistically interpretable potency hypothesis, and formulates adaptive testing strategy for a chemical. The system was constructed with an aim to improve precision and accuracy for predicting LLNA potency beyond ITS-2 (Jaworska et al., J Appl Toxicol 33(11):1353-1364, 2013) by improving representation of chemistry and biology. Among novel elements are corrections for bioavailability both in vivo and in vitro as well as consideration of the individual assays' applicability domains in the prediction process. In ITS-3 structure, three validated alternative assays, DPRA, KeratinoSens and h-CLAT, represent first three key events of the adverse outcome pathway for skin sensitization. The skin sensitization potency prediction is provided as a probability distribution over four potency classes. The probability distribution is converted to Bayes factors to: 1) remove prediction bias introduced by the training set potency distribution and 2) express uncertainty in a quantitative manner, allowing transparent and consistent criteria to accept a prediction. The novel ITS-3 database includes 207 chemicals with a full set of in vivo and in vitro data. The accuracy for predicting LLNA outcomes on the external test set (n = 60) was as follows: hazard (two classes)-100 %, GHS potency classification (three classes)-96 %, potency (four classes)-89 %. This work demonstrates that skin sensitization potency prediction based on data from three key events, and often less, is possible, reliable over broad chemical classes and ready for practical applications. PMID:26612363

  5. Role of the Slug Transcription Factor in Chemically-Induced Skin Cancer

    Directory of Open Access Journals (Sweden)

    Kristine von Maltzan

    2016-02-01

    Full Text Available The Slug transcription factor plays an important role in ultraviolet radiation (UVR-induced skin carcinogenesis, particularly in the epithelial-mesenchymal transition (EMT occurring during tumor progression. In the present studies, we investigated the role of Slug in two-stage chemical skin carcinogenesis. Slug and the related transcription factor Snail were expressed at high levels in skin tumors induced by 7,12-dimethylbenz[α]anthracene application followed by 12-O-tetradecanoylphorbol-13-acetate (TPA treatment. TPA-induced transient elevation of Slug and Snail proteins in normal mouse epidermis and studies in Slug transgenic mice indicated that Slug modulates TPA-induced epidermal hyperplasia and cutaneous inflammation. Although Snail family factors have been linked to inflammation via interactions with the cyclooxygenase-2 (COX-2 pathway, a pathway that also plays an important role in skin carcinogenesis, transient TPA induction of Slug and Snail appeared unrelated to COX-2 expression. In cultured human keratinocytes, TPA induced Snail mRNA expression while suppressing Slug expression, and this differential regulation was due specifically to activation of the TPA receptor. These studies show that Slug and Snail exhibit similar patterns of expression during both UVR and chemical skin carcinogenesis, that Slug and Snail can be differentially regulated under some conditions and that in vitro findings may not recapitulate in vivo results.

  6. 494 Skin Sensitization to Carmine Before Onset of Systemic Allergy to Ingested Carmine

    Science.gov (United States)

    Katada, Yoshinori; Harada, Yoshinori; Azuma, Naoto; Hashimoto, Jun; Saeki, Yukihiko; Tanaka, Toshio

    2012-01-01

    Background Allergic sensitization to food can occur through skin exposure. We investigated anaphylactic cases due to carmine, a food additive extracted from Dactylopius coccus. Methods Screening all patients, who visited our department from January 2000 to December 2009, we identified 2 new such cases. Both had history of rash induced by certain cosmetics containig carmine. We further investigated previous case reports of carmine allergy, whether skin sensitization antedated food allergy or not. Results Case 1: A 26-year-old woman visited our hospital because of anaphylaxis occurred within 5 minutes after ingesting a Japanese YOKAN (sweetened and jellied bean paste). IgE antibodies against common food allergens including beans and wheat were all negative. As the paste contains carmine, we tested specific IgE antibody, which was positive. She had been avoiding using certain cheeks and lips for 2 years, since they cause erythema. These cosmetics emerged as containing carmine. Abstaining from the food additive made her free from anaphylaxis. Case 2: A 30-year-old woman came to our hospital for dyspnea, uriticaria, and bilateral blepharedema, immediately after drinking Campari soda. Her past history was prominent, as she had 4 episodes of anaphylaxis in 4 years, requiring emergency transport twice. All anaphylactic episodes occurred in Italian restaurants when she drank cocktails, which might contain carmine in Campari soda. She had been also sensitive to certain rouges since several years before the first onset of anaphylaxis. It became clear that the rouges contained carmine. In literatures, we found 22 cases with allergy to ingested carmine. It is surprising that all cases were women (aged 25 to 52), while occupationally sensitized patients are predominantly men. As far as we could know, 85.7 % of (6/7) mentioned cases had previous history of sensitization to cosmetics containing carmine. Conclusions In many cases with allergy against ingested carmine, the route of

  7. Is Cytox 3522 (10% methylene-bis-thiocyanate) a human skin sensitizer?

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Hamann, K

    1983-01-01

    Methylene-bis-thiocyanate is an antimicrobial agent in Cytox 3522 (American Cyanamid Corporation) and Nalco 206 (Nalco Chemical Company). Both are wide-spectrum industrial biocides. Cytox 3522 showed a strong sensitization potential in guineau pigs using the Guinea Pig Maximization Test and the O......Methylene-bis-thiocyanate is an antimicrobial agent in Cytox 3522 (American Cyanamid Corporation) and Nalco 206 (Nalco Chemical Company). Both are wide-spectrum industrial biocides. Cytox 3522 showed a strong sensitization potential in guineau pigs using the Guinea Pig Maximization Test...

  8. Self-reported occupational exposure to chemical and physical factors and risk of skin problems

    DEFF Research Database (Denmark)

    Alfonso, Jose Hernan; Thyssen, Jacob P; Tynes, Tore;

    2015-01-01

    Prospective studies on occupational dermatoses in the general working population are sparse. This study investigated prospectively the impact of self-reported occupational exposure to chemicals and physical factors on the risk of skin problems. The cohort comprised respondents drawn randomly from...... the general population in Norway, who were registered employed in 2006 and 2009 (n = 6,745). Indoor dry air (odds ratio (OR) 1.3; 95% confidence interval (95% CI) 1.1-1.6) was a significant baseline predictor of skin problems at follow-up, whereas exposure to cleaning products (OR 1.7; 95% CI 1.2-2.5), water...

  9. Altered thermal sensitivity in facial skin in chronic whiplash-associated disorders

    Institute of Scientific and Technical Information of China (English)

    Birgitta Haggman-Henrikson; Ewa Lampa; Erik Nordh

    2013-01-01

    There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury. Inclusion of manageable routines for valid assessment of the facial sensory capacity is thus needed for comprehensive evaluations of patients exposed to such trauma. The present study investigated facial thermal thresholds in patients with chronic whiplash-associated disorders (WADs) with both a qualitative method and quantitative sensory testing (QST). Ten women with pain and dysfunction following a whiplash injury were compared to 10 healthy age-matched women. Thermal detection thresholds were assessed by qualitative chair-side testing and by QST according to the method-of-limits. Seven test sites in the facial skin (overlying each trigeminal branch bilaterally, and the midpoint of the chin) were examined. The detection warm and cold thresholds were defined as the mean values of 10 individual thresholds. For the WAD patients, the qualitative assessment demonstrated both reduced and increased sensitivity compared to the healthy, whereas QST systematically showed significantly higher detection thresholds (i.e., decreased sensitivity) for both cold and warm stimuli. For the individuals who were assessed as having increased sensitivity in the qualitative assessment, the QST displayed either normal or higher thresholds, i.e., decreased sensitivity. The results suggest that QST is more sensitive for detecting thermal sensory disturbances in the face than a qualitative method. The impaired thermal sensitivity among the patients corroborates the notion of altered thermal detection capacity induced by WAD-related pain.

  10. Niacin Skin Sensitivity Is Increased in Adolescents at Ultra-High Risk for Psychosis.

    Directory of Open Access Journals (Sweden)

    Gregor E Berger

    Full Text Available Most studies provide evidence that the skin flush response to nicotinic acid (niacin stimulation is impaired in schizophrenia. However, only little is known about niacin sensitivity in the ultra-high risk (UHR phase of psychotic disorders.We compared visual ratings of niacin sensitivity between adolescents at UHR for psychosis according to the one year transition outcome (UHR-T n = 11; UHR-NT n = 55 with healthy controls (HC n = 25 and first episode schizophrenia patients (FEP n = 25 treated with atypical antipsychotics.Contrary to our hypothesis niacin sensitivity of the entire UHR group was not attenuated, but significantly increased compared to the HC group, whereas no difference could be found between the UHR-T and UHR-NT groups. As expected, niacin sensitivity of FEP was attenuated compared to HC group. In UHR individuals niacin sensitivity was inversely correlated with omega-6 and -9 fatty acids (FA, but positively correlated with phospholipase A2 (inPLA2 activity, a marker of membrane lipid repair/remodelling.Increased niacin sensitivity in UHR states likely indicates an impaired balance of eicosanoids and omega-6/-9 FA at a membrane level. Our findings suggest that the emergence of psychosis is associated with an increased mobilisation of eicosanoids prior to the transition to psychosis possibly reflecting a "pro-inflammatory state", whereas thereafter eicosanoid mobilisation seems to be attenuated. Potential treatment implications for the UHR state should be further investigated.

  11. Sensitivity of different areas of the flexor aspect of the human forearm to corticosteroid-induced skin blanching.

    Science.gov (United States)

    Meyer, E; Smith, E W; Haigh, J M

    1992-10-01

    The intensity of corticosteroid-induced blanching has been found to vary at different areas of the flexor aspect of the human forearm. A retrospective analysis of 38,880 observations of skin blanching in 56 volunteers was conducted to assess the sensitivity of forearm skin to betamethasone 17-valerate. The mid-forearm appears to be more sensitive to the blanching response than do the areas close to the wrist or elbow. These results indicate that each preparation under evaluation should be applied to several sites along the forearm when using the human skin blanching assay in order to obtain an accurate comparative assessment of corticosteroid release from topical delivery vehicles.

  12. Utilization of reconstructed cultured human skin models as an alternative skin for permeation studies of chemical compounds

    OpenAIRE

    Kano, Satoshi; 藤堂, 浩明; 杉江, 謙一; 藤本, 英哲; 中田, 圭一; 徳留, 嘉寛; 橋本, フミ惠; 杉林, 堅次

    2010-01-01

    Two reconstructed human skin models, EpiskinSM and EpiDermTM, have been approved as alternative membranes for skin corrosive/irritation experiments due to their close correlation with animal skin. Such reconstructed human skin models were evaluated as alternative membranes for skin permeation experiments. Seven drugs with different lipophilicities and almost the same molecular weight were used as test penetrants. Relationships were investigated between permeability coefficients (P values) of ...

  13. Proposal of abolition of the skin sensitivity test before equine rabies immune globulin application

    OpenAIRE

    Cupo, Palmira; AZEVEDO-MARQUES Marisa M. de; SARTI Willy; HERING Sylvia Evelyn

    2001-01-01

    An epizootic outbreak of rabies occurred in 1995 in Ribeirão Preto, SP, with 58 cases of animal rabies (54 dogs, 3 cats and 1 bat) confirmed by the Pasteur Institute of São Paulo, and one human death. The need to provide care to a large number of people for the application of equine rabies immune globulin (ERIG) prevented the execution of the skin sensitivity test (SST) and often also the execution of desensitization, procedures routinely used up to that time at the Emergency Unit of the Univ...

  14. Skin Sensitive Difference of Human Body Sections under Clothing--Multiple Analysis of Skin Surface Temperature Changes

    Institute of Scientific and Technical Information of China (English)

    李俊; 吴海燕; 张渭源

    2003-01-01

    A new researching method on clothing comfort perception is developed.By it the skin surface temperature changes and subjective psychological perception of human body sections stimulated by the same cold stimulation are studied.With the multiple comparison analysis method the changing laws of skin temperature of main human body sections is obtained.

  15. Sub-categorisation of skin corrosive chemicals by the EpiSkin™ reconstructed human epidermis skin corrosion test method according to UN GHS: revision of OECD Test Guideline 431.

    Science.gov (United States)

    Alépée, N; Grandidier, M H; Cotovio, J

    2014-03-01

    The EpiSkin™ skin corrosion test method was formally validated and adopted within the context of OECD TG 431 for identifying corrosive and non-corrosive chemicals. The EU Classification, Labelling and Packaging Regulation (EU CLP) system requires the sub-categorisation of corrosive chemicals into the three UN GHS optional subcategories 1A, 1B and 1C. The present study was undertaken to investigate the usefulness of the validated EpiSkin™ test method to identify skin corrosive UN GHS Categories 1A, 1B and 1C using the original and validated prediction model and adapted controls for direct MTT reduction. In total, 85 chemicals selected by the OECD expert group on skin corrosion were tested in three independent runs. The results obtained were highly reproducible both within (>80%) and between (>78%) laboratories when compared with historical data. Moreover the results obtained showed that the EpiSkin™ test method is highly sensitive (99%) and specific (80%) in discriminating corrosive from non-corrosive chemicals and allows reliable and relevant identification of the different skin corrosive UN GHS subcategories, with high accuracies being obtained for both UN GHS Categories 1A (83%) and 1B/1C (76%) chemicals. The overall accuracy of the test method to subcategorise corrosive chemicals into three or two UN GHS subcategories ranged from 75% to 79%. Considering those results, the revised OECD Test Guideline 431 permit the use of EpiSkin™ for subcategorising corrosive chemicals into at least two classes (Category 1A and Category 1B/1C).

  16. GA(2)LEN skin test study I: GA(2)LEN harmonization of skin prick testing: novel sensitization patterns for inhalant allergens in Europe

    DEFF Research Database (Denmark)

    Heinzerling, L M; Burbach, G J; Edenharter, G;

    2009-01-01

    . This could partly be related to changes in mobility of patients, vegetation or climate in Europe. CONCLUSION: The results of this large pan-European study demonstrate for the first time sensitization patterns for different inhalant allergens in patients across Europe. The standardized skin prick test...... with the standardized allergen battery should be recommended for clinical use and research. Further EU-wide monitoring of sensitization patterns is urgently needed....

  17. SA-I Mechanoreceptor Position in Fingertip Skin May Impact Sensitivity to Edge Stimuli

    Directory of Open Access Journals (Sweden)

    Gregory J. Gerling

    2010-01-01

    Full Text Available Background: The skin plays a role in conditioning mechanical indentation into distributions of stress/strain that mechanoreceptors convert into neural signals. Solid mechanics methods have modelled the skin to predict the in vivo neural response from mechanoreceptors. Despite their promise, current models cannot explain the role that anatomical positioning and receptor organ morphology play in producing differences in neural response. This work hypothesises that the skin's intermediate ridges may help explain, in part, the sensitivity of slowly adapting type I (SA-I mechanoreceptors to edge stimuli. Method: Two finite-element models of the fingertip were built, validated and used to analyse the functionality of the intermediate ridges. One of the two-dimensional, cross-sectional models included intermediate ridges, while the other did not. The analysis sought to determine if intermediate ridges (1 increase the magnitude of strain energy density (SED near the SA-I location and (2 help differentiate one 2.0-mm indenter from two 0.5-mm wide indenters with a 1.0-mm gap. Results: Higher concentrations of SED were found near the tips of the intermediate ridges, the anatomical location that coincides with the SA-I receptors. This first result suggested that the location of the SA-Is in the stiffer epidermal tissue helps magnify their response to edge stimuli. The second result was that both models were equally capable of predicting the spatial structure within the in vivo neural responses, and therefore the addition of intermediate ridges did not help in differentiating the indenters. Conclusion: The finding, a 15%–35% increase in response when the sampling point lies within the stiffer tissue at the same depth, seeks to inform the positioning of force sensors in robotic skin substrates.

  18. Sensitivity and entanglement in the avian chemical compass

    Science.gov (United States)

    Zhang, Yiteng; Berman, Gennady P.; Kais, Sabre

    2014-10-01

    The radical pair mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, using a two-stage model, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle dependent and long enough to allow adequate electron transfer between molecules.

  19. Sensitivity and Entanglement in the Avian Chemical Compass

    CERN Document Server

    Zhang, Yiteng; Kais, Sabre

    2014-01-01

    The Radical Pair Mechanism can help to explain avian orientation and navigation. Some evidence indicates that the intensity of external magnetic fields plays an important role in avian navigation. In this paper, based on a two-stage strategy, we demonstrate that birds could reasonably detect the directions of geomagnetic fields and gradients of these fields using a yield-based chemical compass that is sensitive enough for navigation. Also, we find that the lifetime of entanglement in this proposed compass is angle-dependent and long enough to allow adequate electron transfer between molecules.

  20. Use of silicon for skin and hair care: an approach of chemical forms available and efficacy.

    Science.gov (United States)

    Araújo, Lidiane Advincula de; Addor, Flavia; Campos, Patrícia Maria Berardo Gonçalves Maia

    2016-01-01

    Silicon is the second most abundant element on Earth, and the third most abundant trace element in human body. It is present in water, plant and animal sources. On the skin, it is suggested that silicon is important for optimal collagen synthesis and activation of hydroxylating enzymes, improving skin strength and elasticity. Regarding hair benefits, it was suggested that a higher silicon content in the hair results in a lower rate of hair loss and increased brightness. For these beneficial effects, there is growing interest in scientific studies evaluating the efficacy and safety of using dietary supplements containing silicon. Its use aims at increasing blood levels of this element and improving the skin and its annexes appearance. There are different forms of silicon supplements available and the most important consideration to be made in order to select the best option is related to safety and bioavailability. Silicon supplements are widely used, though there is wide variation in silicon bioavailability, ranging from values below 1% up to values close to 50%, depending on the chemical form. Therefore, the aim of this study was to evaluate the scientific literature related to the different chemical forms of silicon supplements available and the limitations and recent progress in this field. According to reported studies, among the different chemical forms available, the orthosilicic acid (OSA) presents the higher bioavailability, whereas the others forms have absorption inversely proportional to the degree of polymerization. However, clinical studies evaluating safety and efficacy are still lacking. PMID:27438201

  1. Use of silicon for skin and hair care: an approach of chemical forms available and efficacy*

    Science.gov (United States)

    de Araújo, Lidiane Advincula; Addor, Flavia; Campos, Patrícia Maria Berardo Gonçalves Maia

    2016-01-01

    Silicon is the second most abundant element on Earth, and the third most abundant trace element in human body. It is present in water, plant and animal sources. On the skin, it is suggested that silicon is important for optimal collagen synthesis and activation of hydroxylating enzymes, improving skin strength and elasticity. Regarding hair benefits, it was suggested that a higher silicon content in the hair results in a lower rate of hair loss and increased brightness. For these beneficial effects, there is growing interest in scientific studies evaluating the efficacy and safety of using dietary supplements containing silicon. Its use aims at increasing blood levels of this element and improving the skin and its annexes appearance. There are different forms of silicon supplements available and the most important consideration to be made in order to select the best option is related to safety and bioavailability. Silicon supplements are widely used, though there is wide variation in silicon bioavailability, ranging from values below 1% up to values close to 50%, depending on the chemical form. Therefore, the aim of this study was to evaluate the scientific literature related to the different chemical forms of silicon supplements available and the limitations and recent progress in this field. According to reported studies, among the different chemical forms available, the orthosilicic acid (OSA) presents the higher bioavailability, whereas the others forms have absorption inversely proportional to the degree of polymerization. However, clinical studies evaluating safety and efficacy are still lacking. PMID:27438201

  2. Synergistic effects of ethosomes and chemical enhancers on enhancement of naloxone permeation through human skin.

    Science.gov (United States)

    Xu, D H; Zhang, Q; Feng, X; Xu, X; Liang, W Q

    2007-04-01

    The purpose of this study was to investigate the effects of ethosomes, chemical enhancers and their binary combination on the in vitro permeability enhancement of naloxone through human skin. Franz diffusion cells were used for the percutaneous absorption studies. Propylene glycol (PG), N,N-dimethyl formamide (N,N-DMF), N,N-dimethyl acetamide (N,N-DMA), dimethyl sulfoxide (DMSO), Azone and polyethylene glycol 400 (PEG400), were chosen as the chemical enhancers. Naloxone ethosomes showed 11.68 times increase in steady-state flux compared to phosphate buffered solution (PBS). Ethosomes in combination with chemical enhancers synergistically increased (p ethosomal form dramatically enhanced the skin permeation of naloxone in vitro compared with ethosomes (steady-state flux: 96.75 +/- 5.70 microg x cm(-2) x h(-1) vs 20.56 +/- 1.67 microg x cm(-2) x h(-1)). Ethosomal carrier and enhancers accumulated in the skin after 24 h were greater than that of PBS.

  3. Slit2 promotes tumor growth and invasion in chemically induced skin carcinogenesis.

    Science.gov (United States)

    Qi, Cuiling; Lan, Haimei; Ye, Jie; Li, Weidong; Wei, Ping; Yang, Yang; Guo, Simei; Lan, Tian; Li, Jiangchao; Zhang, Qianqian; He, Xiaodong; Wang, Lijing

    2014-07-01

    Slit, a neuronal guidance cue, binds to Roundabout (Robo) receptors to modulate neuronal, leukocytic, and endothelial migration. Slit has been reported to have an important effect on tumor growth and metastasis. In the current study, we evaluated the role of Slit2 in skin tumor growth and invasion in mice using a two-step chemical carcinogenesis protocol. We found that Slit2 expression correlated with the loss of basement membrane in the samples of human skin squamous cell carcinoma at different stages of disease progression. Slit2-Tg mice developed significantly more skin tumors than wild-type mice. Furthermore, the skin tumors that occurred in Slit2-Tg mice were significantly larger than those in the wild-type mice 10 weeks after 7,12-dimethylbenz[a]anthracene initiation until the end of the experiment. We also found that pathological development of the wild-type mice was delayed compared with that of Slit2-Tg mice. To further investigate the mechanism of increasing tumors in Slit2-Tg mice, we analyzed the expression of 5-bromo-2'-deoxyuridine (BrdU) in mouse skin lesions and found that the number of BrdU-positive cells and microvessel density in skin lesions were significantly higher in Slit2-Tg mice than in wild-type mice. Histological staining of PAS and type IV collagen and the colocalization of Slit2 and type IV collagen demonstrated varying degrees of loss of the basement membrane in the skin lesions from Slit2-Tg mice that were at the stage of carcinoma in situ. However, the basement membrane was well defined in the wild-type mice. In addition, MMP2, but not MMP9, was upregulated in the skin tissue of Slit2-Tg mice. Interruption of Slit2-Robo1 signaling by the antibody R5 significantly repressed the invasive capability of the squamous cell carcinoma cell line A431. Taken together, our findings reveal that Slit2 promotes DMBA/TPA-induced skin tumorigenesis by increasing cell proliferation, microvessel density, and invasive behavior of cutaneous squamous

  4. Application of the KeratinoSens™ assay for assessing the skin sensitization potential of agrochemical active ingredients and formulations.

    Science.gov (United States)

    Settivari, Raja S; Gehen, Sean C; Amado, Ricardo Acosta; Visconti, Nicolo R; Boverhof, Darrell R; Carney, Edward W

    2015-07-01

    Assessment of skin sensitization potential is an important component of the safety evaluation process for agrochemical products. Recently, non-animal approaches including the KeratinoSens™ assay have been developed for predicting skin sensitization potential. Assessing the utility of the KeratinoSens™ assay for use with multi-component mixtures such as agrochemical formulations has not been previously evaluated and is a significant need. This study was undertaken to evaluate the KeratinoSens™ assay prediction potential for agrochemical formulations. The assay was conducted for 8 agrochemical active ingredients (AIs) including 3 sensitizers (acetochlor, meptyldinocap, triclopyr), 5 non-sensitizers (aminopyralid, clopyralid, florasulam, methoxyfenozide, oxyfluorfen) and 10 formulations for which in vivo sensitization data were available. The KeratinoSens™ correctly predicted the sensitization potential of all the AIs. For agrochemical formulations it was necessary to modify the standard assay procedure whereby the formulation was assumed to have a common molecular weight. The resultant approach correctly predicted the sensitization potential for 3 of 4 sensitizing formulations and all 6 non-sensitizing formulations when compared to in vivo data. Only the meptyldinocap-containing formulation was misclassified, as a result of high cytotoxicity. These results demonstrate the promising utility of the KeratinoSens™ assay for evaluating the skin sensitization potential of agrochemical AIs and formulations. PMID:25981449

  5. Physicochemical properties of pH-sensitive hydrogels based on hydroxyethyl cellulose-hyaluronic acid and for applications as transdermal delivery systems for skin lesions.

    Science.gov (United States)

    Kwon, Soon Sik; Kong, Bong Ju; Park, Soo Nam

    2015-05-01

    We investigated the physicochemical properties of pH-sensitive hydroxyethyl cellulose (HEC)/hyaluronic acid (HA) complex hydrogels containing isoliquiritigenin (ILTG), and discussed potential applications as transdermal delivery systems for the treatment of skin lesions caused by pH imbalance. HA has skin compatibility and pH functional groups and HEC serves as scaffold to build hydrogels with varied HCE:HA mass ratio. Hydrogels were synthesized via chemical cross-linking, and three-dimensional network structures were characterized via scanning electron microscopy (SEM). The swelling properties and polymer ratios of the hydrogels were investigated at pH values in the range 1-13. HECHA13 (i.e., an HEC:HA mass ratio of 1:3) was found to have optimal rheological and adhesive properties, and was used to investigate the drug release efficiency as a function of pH; the efficiency was greater than 70% at pH 7. Antimicrobial activity assays against Propionibacterium acnes were conducted to take advantage of the pH-sensitive properties of HECHA13. At pH 7, we found that HECHA13, which contained ILTG, inhibited the growth of P. acnes. Furthermore, HECHA13 was found to exhibit excellent permeability into the skin, which penetrated mostly via the hair follicle. These results indicate that this pH-sensitive hydrogel is effective as a transdermal delivery system for antimicrobial therapeutics, with potential applications in the treatment of acne.

  6. Assessing the sensitivity of human skin hyperspectral responses to increasing anemia severity levels

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Dey, Ankita; Chen, Tenn F.

    2015-09-01

    Anemia is a prevalent medical condition that seriously affects millions of people all over the world. In many regions, not only its initial detection but also its monitoring are hindered by limited access to laboratory facilities. This situation has motivated the development of a wide range of optical devices and procedures to assist physicians in these tasks. Although noticeable progress has been achieved in this area, the search for reliable, low-cost, and risk-free solutions still continues, and the strengthening of the knowledge base about this disorder and its effects is essential for the success of these initiatives. We contribute to these efforts by closely examining the sensitivity of human skin hyperspectral responses (within and outside the visible region of the light spectrum) to reduced hemoglobin concentrations associated with increasing anemia severity levels. This investigation, which involves skin specimens with distinct biophysical and morphological characteristics, is supported by controlled in silico experiments performed using a predictive light transport model and measured data reported in the biomedical literature. We also propose a noninvasive procedure to be employed in the monitoring of this condition at the point-of-care.

  7. Rat epidermal keratinocyte organotypic culture (ROC) as a model for chemically induced skin irritation testing

    International Nuclear Information System (INIS)

    The potential of rat epidermal keratinocyte (REK) organotypic culture (ROC) with proper stratum corneum barrier as a model for screening skin irritants was evaluated. The test chemicals were selected from ECETOC database (1995) and the observed in vitro irritation potential was compared to ECETOC in vivo primary irritation index (PII), to EU risk phrases, and to the harmonized OECD criteria. Chemicals were applied onto the stratum corneum surface of ROC for 30 min and samples were taken from the underlying medium at 4 and 8 h after exposure. Cell membrane integrity (determined by LDH assay) and pro-inflammatory effect (determined by IL-1α release) were verified at both time points and correlated to PII values. The best correlation (R 2 = 0.831) was seen with LDH leakage test. Based on obtained data, chemicals were classified according to criteria defined by EU and OECD. From 12 chemicals, only two were incorrectly classified according to OECD criteria when using LDH leakage and IL-1α release as irritation markers. At the end of experiment, chemical-treated ROC cultures were fixed and histological changes were assessed. Typical signs for irritation were lightly stained cytoplasm, condensed nuclei, cellular vacuolization, eosinophilic cytoplasms, and blebbing. These irritation effects of chemicals were graded visually into four classes (A-D). The extent of morphological perturbations of the cultures mostly correlated with PII. The present results indicate the validity of the ROC model in predicting skin irritation potential of chemicals and show that the use of set of irritation markers with different mechanistic responses gives more information on irritation than if only one marker was used

  8. Sensitization to Aeroallergens in Patients with Respiratory Allergies Based on Skin-Prick Test Results

    Directory of Open Access Journals (Sweden)

    G Bejtullahu

    2012-10-01

    Full Text Available Background: The aim of this study was to identify the most common aeroallergens in patients with asthma and rhinitis.Methods: The study enrolled 102 participants including 64 patients with respiratory allergies (among them 15 were clinically diagnosed as asthma patients, 41 with rhinitis, 8 were both and 38 healthy controls. All of participants were subject of skin prick tests (SPT with series of common allergenic extracts. Sera from all participants were tested for total IgE and eosinophil count. To measure airflow limitation and reversibility in asthma patients the pulmonary function testing were carried out.Results: M/F ratio was 1:1.6 in patients and 1:0.7 in control group with mean age 28.88 year (SD 13.16; range 6 – 55year and 20.47 respectively (SD 1.16; range 19-23 year. The most common risk factors in these patients were total IgE more than 100 IU/ml, eosinophils above 4% and positive family history of atopy. Skin prick testing results showed prevalence rates for allergen groups in this manner: house dust mites 81.3 %, pollens 57.8 %, animal dandruff12.5% and moulds 4.9%. Polysensitization was common in 51.6% of all sensitized patients being positive to more than one group of allergens.Conclusion: House dust mites are the main sensitizing allergens among our allergic patients as well as healthy controls. Next in importance, in all participants, are grasses. This pattern of prevalence was expected based on herbal geography, climate and specially lifestyle. It was also compatible with the results from studies carried out in places with the same habitat.

  9. The credible forensic psychiatric evaluation in multiple chemical sensitivity litigation.

    Science.gov (United States)

    Simon, R I

    1998-01-01

    The forensic psychiatrist must be able to perform a credible psychiatric evaluation and render a competent psychiatric opinion in hotly contested multiple chemical sensitivity (MCS) litigation. Forensic psychiatrists are often requested to evaluate MCS claimants by third party payers, employers, lawyers, and government agencies regarding health care costs and disability payments, workers' compensation claims, unemployment benefits, workplace accommodation reimbursements for special housing and environmental needs, civil litigation, and other claims. The credible forensic psychiatric evaluation of MCS litigants is described using the multiaxial diagnostic system of DSM-IV. Forensic psychiatrists must avoid becoming polarized by the current MCS controversy. The ethical requirements of honesty and striving for objectivity can be met by keeping separate the roles of therapist and expert, staying abreast of the scientific literature regarding MCS, and understanding the role of the psychiatric expert in MCS litigation. PMID:9785280

  10. Targeted expression of tumor necrosis factor-related apoptosis-inducing ligand TRAIL in skin protects mice against chemical carcinogenesis

    Directory of Open Access Journals (Sweden)

    Gronemeyer Hinrich

    2011-04-01

    Full Text Available Abstract Background Gene ablation studies have revealed that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, Apo2L, TNFSF10 plays a crucial role in tumor surveillance, as TRAIL-deficient mice exhibit an increased sensitivity to different types of tumorigenesis. In contrast, possible tumor-protective effect of increased levels of endogenous TRAIL expression in vivo has not been assessed yet. Such models will provide important information about the efficacy of TRAIL-based therapies and potential toxicity in specific tissues. Methods To this aim, we engineered transgenic mice selectively expressing TRAIL in the skin and subjected these mice to a two-step chemical carcinogenesis protocol that generated benign and preneoplastic lesions. We were therefore able to study the effect of increased TRAIL expression at the early steps of skin tumorigenesis. Results Our results showed a delay of tumor appearance in TRAIL expressing mice compared to their wild-type littermates. More importantly, the number of tumors observed in transgenic animals was significantly lower than in the control animals, and the lesions observed were mostly benign. Interestingly, Wnt/β-catenin signaling differed between tumors of wild-type and TRAIL transgenics. Conclusion Altogether, these data reveal that, at least in this model, TRAIL is able on its own to act on pre-transformed cells, and reduce their tumorigenic potential.

  11. Optimization of a chemical method for skinning of sardines (Sardina pilchardus during canning processing

    Directory of Open Access Journals (Sweden)

    Manuela Vaz Velho

    2014-06-01

    Full Text Available Most of sardine (Sardina pilchardus catches is used for canning purposes. The most common product presentation is a beheaded sardine with skin and bones packed in a tin can. Canned sardines can also be presented skinless and boneless. For this last type of product, after beheading and evisceration, sardines are placed in trays, cooked and then skinned by hand, one by one, and placed in the tins, a process involving high labour costs. The aim of this work was to develop a chemical process for peeling raw sardines and its subsequent application in a canning industry processing line just after the beheading and evisceration step and before cooking. Potassium hydroxide treatments (pellets a.r. 85% KOH were applied at concentrations of 2, 3 and 4% (v/v, distilled water. Frozen sardines were beheaded and eviscerated after thawing and immersed in the different potassium hydroxide solutions at 93ºC (pH respectively 13, 13 and 13.02 for 3 min and further washed with distilled water at 100°C. In this first set of experiments, fat sardines were used (average of 9.86% of fat, w/w. The best performance, with respect to skin removal, was achieved with the 2% potassium hydroxide immersion (pH 13. With this treatment the skin was totally removed after immersion. With the other tested concentrations portions of skin were always visible and in some cases changes in texture with breakdown of muscle structure and changes of colour occurred. It was decided to perform a second set of experiments using the 2% KOH treatment, but this time applied to low fat sardines (average of 4.77% of fat, w/w, following the same subsequent procedures. The results showed that the lower fat sardines are more prone to surface changes of colour and major muscle breaks than fat sardines after the potassium hydroxide treatment. In the canning industry for this type of product (skinless and boneless only fat sardines are used to assure the total removal of skin. This treatment of 2% KOH

  12. KCNQ Potassium Channels Modulate Sensitivity of Skin Down-hair (D-hair) Mechanoreceptors.

    Science.gov (United States)

    Schütze, Sebastian; Orozco, Ian J; Jentsch, Thomas J

    2016-03-11

    M-current-mediating KCNQ (Kv7) channels play an important role in regulating the excitability of neuronal cells, as highlighted by mutations in Kcnq2 and Kcnq3 that underlie certain forms of epilepsy. In addition to their expression in brain, KCNQ2 and -3 are also found in the somatosensory system. We have now detected both KCNQ2 and KCNQ3 in a subset of dorsal root ganglia neurons that correspond to D-hair Aδ-fibers and demonstrate KCNQ3 expression in peripheral nerve endings of cutaneous D-hair follicles. Electrophysiological recordings from single D-hair afferents from Kcnq3(-/-) mice showed increased firing frequencies in response to mechanical ramp-and-hold stimuli. This effect was particularly pronounced at slow indentation velocities. Additional reduction of KCNQ2 expression further increased D-hair sensitivity. Together with previous work on the specific role of KCNQ4 in rapidly adapting skin mechanoreceptors, our results show that different KCNQ isoforms are specifically expressed in particular subsets of mechanosensory neurons and modulate their sensitivity directly in sensory nerve endings.

  13. What Happens after Activation of Ascaridole? Reactive Compounds and Their Implications for Skin Sensitization.

    Science.gov (United States)

    Chittiboyina, Amar G; Avonto, Cristina; Khan, Ikhlas A

    2016-09-19

    To replace animal testing and improve the prediction of skin sensitization, significant attention has been directed to the use of alternative methods. The direct peptide reactivity assay (DPRA), the regulatory agencies' approved alternative in chemico method, has been applied for understanding the sensitization capacity of activated ascaridole. Ascaridole, the oxidative metabolite of α-terpinene, is considered to be one of the components responsible for the contact allergy associated with essential oils derived from Chenopodium and Melaleuca species. The recently developed high-throughput screening based on the dansyl cysteamine (HTS-DCYA) method was applied to understand the reported enhanced reactivity of activated ascaridole and possibly to identify the resulting elusive radical or other reactive species. For the first time, a substituted cyclohexenone was identified as a potential electrophilic intermediate resulting in higher depletion of nucleophilic DCYA, along with several nonreactive byproducts of ascaridole via a radical degradation mechanism. Formation of electrophilic species via radical degradation is one of the possible pathways should be considered for the peptide reactivity of in aged tea tree oil or oils rich in terpinenes along with commonly believed reactants, allylic-epoxides and allylic-peroxides. PMID:27513446

  14. Development, fabrication, and modeling of highly sensitive conjugated polymer based piezoresistive sensors in electronic skin applications

    Science.gov (United States)

    Khalili, Nazanin; Naguib, Hani E.; Kwon, Roy H.

    2016-04-01

    Human intervention can be replaced through development of tools resulted from utilizing sensing devices possessing a wide range of applications including humanoid robots or remote and minimally invasive surgeries. Similar to the five human senses, sensors interface with their surroundings to stimulate a suitable response or action. The sense of touch which arises in human skin is among the most challenging senses to emulate due to its ultra high sensitivity. This has brought forth novel challenging issues to consider in the field of biomimetic robotics. In this work, using a multiphase reaction, a polypyrrole (PPy) based hydrogel is developed as a resistive type pressure sensor with an intrinsically elastic microstructure stemming from three dimensional hollow spheres. Furthermore, a semi-analytical constriction resistance model accounting for the real contact area between the PPy hydrogel sensors and the electrode along with the dependency of the contact resistance change on the applied load is developed. The model is then solved using a Monte Carlo technique and the sensitivity of the sensor is obtained. The experimental results showed the good tracking ability of the proposed model.

  15. Thresholds of skin sensitivity are partially influenced by mechanical properties of the skin on the foot sole

    OpenAIRE

    Strzalkowski, Nicholas D J; Triano, John J; Lam, Chris K; Templeton, Cale A; Bent, Leah R

    2015-01-01

    Across the foot sole, there are vibration and monofilament sensory differences despite an alleged even distribution of cutaneous afferents. Mechanical property differences across foot sole sites have been proposed to account for these differences. Vibration (VPT; 3 Hz, 40 Hz, 250 Hz), and monofilament (MF) perception threshold measurements were compared with skin hardness, epidermal thickness, and stretch response across five foot sole locations in young healthy adults (n = 22). Perceptual th...

  16. Comprehensive Monte-Carlo simulator for optimization of imaging parameters for high sensitivity detection of skin cancer at the THz

    Science.gov (United States)

    Ney, Michael; Abdulhalim, Ibrahim

    2016-03-01

    Skin cancer detection at its early stages has been the focus of a large number of experimental and theoretical studies during the past decades. Among these studies two prominent approaches presenting high potential are reflectometric sensing at the THz wavelengths region and polarimetric imaging techniques in the visible wavelengths. While THz radiation contrast agent and source of sensitivity to cancer related tissue alterations was considered to be mainly the elevated water content in the cancerous tissue, the polarimetric approach has been verified to enable cancerous tissue differentiation based on cancer induced structural alterations to the tissue. Combining THz with the polarimetric approach, which is considered in this study, is examined in order to enable higher detection sensitivity than previously pure reflectometric THz measurements. For this, a comprehensive MC simulation of radiative transfer in a complex skin tissue model fitted for the THz domain that considers the skin`s stratified structure, tissue material optical dispersion modeling, surface roughness, scatterers, and substructure organelles has been developed. Additionally, a narrow beam Mueller matrix differential analysis technique is suggested for assessing skin cancer induced changes in the polarimetric image, enabling the tissue model and MC simulation to be utilized for determining the imaging parameters resulting in maximal detection sensitivity.

  17. Sensitization to Food Additives in Patients with Allergy: A Study Based on Skin Test and Open Oral Challenge.

    Science.gov (United States)

    Moghtaderi, Mozhgan; Hejrati, Zinatosadat; Dehghani, Zahra; Dehghani, Faranak; Kolahi, Niloofar

    2016-06-01

    There has been a great increase in the consumption of various food additives in recent years. The purpose of this study was to identify the incidence of sensitization to food additives by using skin prick test in patients with allergy and to determine the concordance rate between positive skin tests and oral challenge in hypersensitivity to additives. This cross-sectional study included 125 (female 71, male 54) patients aged 2-76 years with allergy and 100 healthy individuals. Skin tests were performed in both patient and control groups with 25 fresh food additives. Among patients with allergy, 22.4% showed positive skin test at least to one of the applied materials. Skin test was negative to all tested food additives in control group. Oral food challenge was done in 28 patients with positive skin test, in whom 9 patients showed reaction to culprit (Concordance rate=32.1%). The present study suggested that about one-third of allergic patients with positive reaction to food additives showed positive oral challenge; it may be considered the potential utility of skin test to identify the role of food additives in patients with allergy. PMID:27424134

  18. Modulatory influence of Phyllanthus niruri on oxidative stress, antioxidant defense and chemically induced skin tumors.

    Science.gov (United States)

    Sharma, Priyanka; Parmar, Jyoti; Verma, Preeti; Goyal, Pradeep Kumar

    2011-01-01

    The present study evaluates the modulatory potential of Phyllanthus niruri on chemically induced skin carcinogenesis, and its influence on oxidative stress and the antioxidant defense system. Oral administration of P. niruri extract (PNE), during peri- (Gr. III), post- (Gr. IV), or peri- and post- (Gr. V) initiational stages of 7,12-dimethylbenz(a) anthracene (DMBA)-croton oil–induced papillomagenesis considerably reduced tumor burden to 4.20, 4.00, and 3.33(positive control value 6.20); cumulative number of papillomas to 21, 16, and 10, respectively, (positive control value 62); and incidence of mice bearing papillomas to 50, 40, and 30%, respectively (positive control value 100%), but significantly increased the average latent period to 10.14, 10.62, and 11.60, and inhibition of tumor multiplicity to 66, 74,and 83%, respectively. Enzyme analysis of skin and liver showed a significant (p ≤ 0.05, ≤ 0.01, ≤ 0.001) elevation in antioxidant parameters such as superoxide dismutase, catalase, glutathione, and vitamin C in PNE-treated groups (Gr. III–V) when compared with the carcinogen-treated control (Gr. II). The elevated level of lipid peroxidation in the carcinogen-treated positive control group was significantly (p ≤ 0.05, ≤ 0.01, ≤ 0.001) inhibited by PNE administration. These results indicate that P. niruri extract has potentiality to reduce skin papillomas by enhancing antioxidant defense system. PMID:21609315

  19. Long-term repeatability of the skin prick test is high when supported by history or allergen-sensitivity tests

    DEFF Research Database (Denmark)

    Bødtger, Uffe; Jacobsen, C R; Poulsen, L K;

    2003-01-01

    BACKGROUND: Long-term reproducibility of the skin-prick test (SPT) has been questioned. The aim of the study was to investigate the clinical relevance of SPT changes. METHODS: SPT to 10 common inhalation allergens was performed annually from 1999 to 2001 in 25 nonsensitized and 21 sensitized...

  20. Seasonal dynamics of chemokine receptors and CD62L in subjects with asymptomatic skin sensitization to birch and grass pollen

    DEFF Research Database (Denmark)

    Assing, K; Bodtger, U; Poulsen, Lars K.

    2006-01-01

    Asymptomatic skin sensitization (AS) has been shown to be a risk factor for respiratory allergic disease. CCR4, CXCR1 and CD62L have all been assigned a role in the immunopathogenesis of allergy. Memory T-cell expression of CCR4, CXCR1 and CD62L has not hitherto been investigated in subjects with...

  1. Optimization of spectral sensitivities of mosaic five-band camera for estimating chromophore densities from skin images including shading and surface reflections

    Science.gov (United States)

    Hirose, Misa; Akaho, Rina; Maita, Chikashi; Sugawara, Mai; Tsumura, Norimichi

    2016-06-01

    In this paper, the spectral sensitivities of a mosaic five-band camera were optimized using a numerical skin phantom to perform the separation of chromophore densities, shading and surface reflection. To simulate the numerical skin phantom, the spectral reflectance of skin was first calculated by Monte Carlo simulation of photon migration for different concentrations of melanin, blood and oxygen saturation levels. The melanin and hemoglobin concentration distributions used in the numerical skin phantom were obtained from actual skin images by independent component analysis. The calculated components were assigned as concentration distributions. The spectral sensitivities of the camera were then optimized using a nonlinear technique to estimate the spectral reflectance for skin separation. In this optimization, the spectral sensitivities were assumed to be normally distributed, and the sensor arrangement was identical to that of a conventional mosaic five-band camera. Our findings demonstrated that spectral estimation could be significantly improved by optimizing the spectral sensitivities.

  2. Comparative DNA microarray analysis of human monocyte derived dendritic cells and MUTZ-3 cells exposed to the moderate skin sensitizer cinnamaldehyde

    International Nuclear Information System (INIS)

    The number of studies involved in the development of in vitro skin sensitization tests has increased since the adoption of the EU 7th amendment to the cosmetics directive proposing to ban animal testing for cosmetic ingredients by 2013. Several studies have recently demonstrated that sensitizers induce a relevant up-regulation of activation markers such as CD86, CD54, IL-8 or IL-1β in human myeloid cell lines (e.g., U937, MUTZ-3, THP-1) or in human peripheral blood monocyte-derived dendritic cells (PBMDCs). The present study aimed at the identification of new dendritic cell activation markers in order to further improve the in vitro evaluation of the sensitizing potential of chemicals. We have compared the gene expression profiles of PBMDCs and the human cell line MUTZ-3 after a 24-h exposure to the moderate sensitizer cinnamaldehyde. A list of 80 genes modulated in both cell types was obtained and a set of candidate marker genes was selected for further analysis. Cells were exposed to selected sensitizers and non-sensitizers for 24 h and gene expression was analyzed by quantitative real-time reverse transcriptase-polymerase chain reaction. Results indicated that PIR, TRIM16 and two Nrf2-regulated genes, CES1 and NQO1, are modulated by most sensitizers. Up-regulation of these genes could also be observed in our recently published DC-activation test with U937 cells. Due to their role in DC activation, these new genes may help to further refine the in vitro approaches for the screening of the sensitizing properties of a chemical.

  3. In vivo imaging of dermal collagen in skin burn by collagen-sensitive second-harmonic-generation microscopy

    Science.gov (United States)

    Yasui, Takeshi; Tanaka, Ryosuke; Hase, Eiji; Fukushima, Shu-ichiro; Araki, Tsutomu

    2013-02-01

    Optical assessment of skin burns is possible with second-harmonic-generation (SHG) microscopy due to its high sensitivity to thermal denaturation of collagen molecules. In contrast to previous studies that were performed using excised tissue specimens ex vivo, in this study, we demonstrated in vivo observation of dermal collagen fibers in living rat burn models with SHG microscopy. We confirmed that changes in SHG vanishing patterns in the SHG images depended on the burn degree. The results imply that SHG microscopy can be used as a low-invasiveness, highly quantitative tool for skin burn assessment.

  4. GA(2)LEN skin test study II: clinical relevance of inhalant allergen sensitizations in Europe

    DEFF Research Database (Denmark)

    Burbach, G J; Heinzerling, L M; Edenharter, G;

    2009-01-01

    BACKGROUND: Skin prick testing is the standard for diagnosing IgE-mediated allergies. A positive skin prick reaction, however, does not always correlate with clinical symptoms. A large database from a Global Asthma and Allergy European Network (GA(2)LEN) study with data on clinical relevance...... the clinical relevance of positive skin prick test reactions against inhalant allergens considering the predominating type of symptoms in a pan-European population of patients presenting with suspected allergic disease. METHODS: Clinical relevance of skin prick tests was recorded with regard to patient history...

  5. Transfer of a two-tiered keratinocyte assay: IL-18 production by NCTC2544 to determine the skin sensitizing capacity and epidermal equivalent assay to determine sensitizer potency

    DEFF Research Database (Denmark)

    Teunis, Marc; Corsini, Emanuela; Smits, Mieke;

    2013-01-01

    At present, the identification of potentially sensitizing chemicals is carried out using animal models. However, it is very important from ethical, safety and economic point of view to have biological markers to discriminate allergy and irritation events, and to be able to classify sensitizers....... The aim of this study is to show the transferability of the two-tiered approach with training chemicals: 3 sensitizers (DNCB, resorcinol, pPD) and 1 non sensitizer (lactic acid) in tier 1 and 2 sensitizers with different potency in tier 2 (DNCB; extreme and resorcinol; moderate). The chemicals were tested...... in a non-coded fashion. Here we describe the transferability to naïve laboratories, the establishment of the standard operating procedure, critical points, acceptance criteria and project management. Both assays were successfully transferred to laboratories that had not performed the assays previously...

  6. Allergological and Toxicological Aspects in a Multiple Chemical Sensitivity Cohort

    Directory of Open Access Journals (Sweden)

    Paolo D. Pigatto

    2013-01-01

    Full Text Available Background. Multiple chemical sensitivity (MCS is a chronic condition characterized by an exaggerated response to toxicants. We ascertained the prevalence of allergy to metals and toxicological aspects in MCS patients. Methods. We conducted a retrospective review of medical records of 41 patients with MCS. We performed patch testing (n=21 for dental series and did lymphocyte transformation test (n=18 for metals. We measured mercury in samples of blood (n=19, urine (n=19, saliva (n=20, and scalp hair (n=17 to investigate the association between mercury levels and cases of MCS. Results. The prevalence of metal immune hypersensitivity in a subset of 26 patients was 92.3 percent. Elevations of mercury occurred in 81.2 percent (26 of 32. The mean (±SD in blood concentrations of mercury was 7.6±13.6 μg/L; mean in urine was 1.9±2.5 μg/L; mean in scalp hair was 2.2±2.5 μg/g; mean in saliva was 38.1±52.1 μg/L. Subgroup analyses showed that elevation of mercury levels in biological matrices were associated with mercury amalgams in patients with MCS (22 patients, compared with controls (8 patients (odds ratio 11 : 95 percent confidence interval 1.5 to 81.6; P=0.023. Conclusions. Our data show an increased prevalence of metal allergy and elevation of mercury levels in bioindicators among patients with MCS.

  7. Low back skin sensitivity has minimal impact on active lumbar spine proprioception and stability in healthy adults.

    Science.gov (United States)

    Beaudette, Shawn M; Larson, Katelyn J; Larson, Dennis J; Brown, Stephen H M

    2016-08-01

    The purpose of the current work was to (1) determine whether low back cutaneous sensitivity could be reduced through the use of a topical lidocaine-prilocaine anesthetic (EMLA(®)) to mirror reductions reported in chronic lower back pain (CLBP) patients, as well as to (2) identify whether reductions in cutaneous sensitivity resulted in decreased lumbar spine proprioception, neuromuscular control and dynamic stability. Twenty-eight healthy participants were divided equally into matched EMLA and PLACEBO treatment groups. Groups completed cutaneous minimum monofilament and two-point discrimination (TPD) threshold tests, as well as tests of sagittal and axial lumbar spine active repositioning error, seated balance and repeated lifting dynamic stability. These tests were administered both before and after the application of an EMLA or PLACEBO treatment. Results show that low back minimum monofilament and TPD thresholds were significantly increased within the EMLA group. Skin sensitivity remained unchanged in the PLACEBO group. In the EMLA group, decreases in low back cutaneous sensitivity had minimal effect on low back proprioception (active sagittal and axial repositioning) and dynamic stability (seated balance and repeated lifting). These findings demonstrate that treating the skin of the low back with an EMLA anesthetic can effectively decrease the cutaneous sensitivity of low back region. Further, these decreases in peripheral cutaneous sensitivity are similar in magnitude to those reported in CLBP patients. Within this healthy population, decreased cutaneous sensitivity of the low back region has minimal influence on active lumbar spine proprioception, neuromuscular control and dynamic stability. PMID:27010722

  8. Clinical characteristics of chemical sensitivity: an illustrative case history of asthma and MCS.

    OpenAIRE

    Ross, G H

    1997-01-01

    A case history of the induction of asthma and chemical sensitivity in a 42-year-old registered nurse illustrates several of the characteristic features of multiple chemical sensitivity (MCS). This patient's problems started shortly after moving into a new home under construction, with associated chemical exposures. Other MCS patients report the onset of the condition with other chemical exposures such as those encountered at their places of work or use of pesticides at their residences. Patie...

  9. Knockdown of Filaggrin Impairs Diffusion Barrier Function and Increases UV Sensitivity in a Human Skin Model

    NARCIS (Netherlands)

    M. Mildner; J. Jin; L. Eckhart; S. Kezic; F. Gruber; C. Barresi; C. Stremnitzer; M. Buchberger; V. Mlitz; C. Ballaun; B. Sterniczky; D. Födinger; E. Tschachler

    2010-01-01

    Loss-of-function mutations in the filaggrin gene are associated with ichthyosis vulgaris and atopic dermatitis. To investigate the impact of filaggrin deficiency on the skin barrier, filaggrin expression was knocked down by small interfering RNA (siRNA) technology in an organotypic skin model in vit

  10. Proposal of abolition of the skin sensitivity test before equine rabies immune globulin application

    Directory of Open Access Journals (Sweden)

    CUPO Palmira

    2001-01-01

    Full Text Available An epizootic outbreak of rabies occurred in 1995 in Ribeirão Preto, SP, with 58 cases of animal rabies (54 dogs, 3 cats and 1 bat confirmed by the Pasteur Institute of São Paulo, and one human death. The need to provide care to a large number of people for the application of equine rabies immune globulin (ERIG prevented the execution of the skin sensitivity test (SST and often also the execution of desensitization, procedures routinely used up to that time at the Emergency Unit of the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (EU-UHFMRP-USP, a reference hospital for the application of heterologous sera. In view of our positive experience of several years with the abolition of SST and of the use of premedication before the application of antivenom sera, we used a similar schedule for ERIG application. Of the 1489 victims of animal bites, 1054 (71% received ERIG; no patient was submitted to SST and all received intravenously anti-histamines (anti-H1 + anti-H2 and corticosteroids before the procedure. The patients were kept under observation for 60 to 180 minutes and no adverse reaction was observed. On the basis of these results, since December 1995 ERIG application has been decentralized in Ribeirão Preto and has become the responsibility of the Emergency Unit of the University Hospital and the Central Basic Health Unit, where the same routine is used. Since then, 4216 patients have received ERIG (1818 at the Basic Health Unit and 2398 at the EU-UHFMRP, with no problems. The ideal would be the routine use of human rabies immune globulin (HRIG in public health programs, but this is problematic, because of their high cost. However, while this does not occur, the use of SST is no longer justified at the time of application of ERIG, in view of the clinical evidence of low predictive value and low sensitivity of SST involving the application of heterologous sera. It is very important to point out

  11. Non-allergic cutaneous reactions in airborne chemical sensitivity--a population based study

    DEFF Research Database (Denmark)

    Berg, Nikolaj Drimer; Linneberg, Allan; Thyssen, Jacob Pontoppidan;

    2011-01-01

    the relationship between cutaneous reactions from patch testing and self-reported severity of chemical sensitivity to common airborne chemicals. A total of 3460 individuals participating in a general health examination, Health 2006, were patch tested with allergens from the European standard series and screened...... for chemical sensitivity with a standardised questionnaire dividing the participants into four severity groups of chemical sensitivity. Both allergic and non-allergic cutaneous reactions--defined as irritative, follicular, or doubtful allergic reactions--were analysed in relationship with severity of chemical...... most severe groups of self-reported sensitivity to airborne chemicals. When adjusting for confounding, associations were weakened, and only non-allergic cutaneous reactions were significantly associated with individuals most severely affected by inhalation of airborne chemicals (odds ratio = 2.5, p = 0...

  12. Sensitivity of the electric dipole polarizability to the neutron skin thickness in ${}^{208}$Pb

    CERN Document Server

    Roca-Maza, X; Colo', G; Nazarewicz, W; Paar, N; Piekarewicz, J; Reinhard, P -G; Vretenar, D; 10.1063/1.4764239

    2012-01-01

    The static dipole polarizability, $\\alpha_{\\rm D}$, in ${}^{208}$Pb has been recently measured with high-resolution via proton inelastic scattering at the Research Center for Nuclear Physics (RCNP). This observable is thought to be intimately connected with the neutron skin thickness, $r_{\\rm skin}$, of the same nucleus and, more fundamentally, it is believed to be associated with the density dependence of the nuclear symmetry energy. The impact of $r_{\\rm skin}$ on $\\alpha_{\\rm D}$ in ${}^{208}$Pb is investigated and discussed on the basis of a large and representative set of relativistic and non-relativistic nuclear energy density functionals (EDF).

  13. Polarization-Sensitive Hyperspectral Imaging in vivo: A Multimode Dermoscope for Skin Analysis

    Science.gov (United States)

    Vasefi, Fartash; MacKinnon, Nicholas; Saager, Rolf B.; Durkin, Anthony J.; Chave, Robert; Lindsley, Erik H.; Farkas, Daniel L.

    2014-05-01

    Attempts to understand the changes in the structure and physiology of human skin abnormalities by non-invasive optical imaging are aided by spectroscopic methods that quantify, at the molecular level, variations in tissue oxygenation and melanin distribution. However, current commercial and research systems to map hemoglobin and melanin do not correlate well with pathology for pigmented lesions or darker skin. We developed a multimode dermoscope that combines polarization and hyperspectral imaging with an efficient analytical model to map the distribution of specific skin bio-molecules. This corrects for the melanin-hemoglobin misestimation common to other systems, without resorting to complex and computationally intensive tissue optical models. For this system's proof of concept, human skin measurements on melanocytic nevus, vitiligo, and venous occlusion conditions were performed in volunteers. The resulting molecular distribution maps matched physiological and anatomical expectations, confirming a technologic approach that can be applied to next generation dermoscopes and having biological plausibility that is likely to appeal to dermatologists.

  14. Assessment of the sensitizing potency of preservatives with chance of skin contact by the loose-fit coculture-based sensitization assay (LCSA).

    Science.gov (United States)

    Sonnenburg, Anna; Schreiner, Maximilian; Stahlmann, Ralf

    2015-12-01

    Parabens, methylisothiazolinone (MI) and its derivative methylchloroisothiazolinone (MCI), are commonly used as preservatives in personal care products. They can cause hypersensitivity reactions of the human skin. We have tested a set of nine parabens, MI alone and in combination with MCI in the loose-fit coculture-based sensitization assay (LCSA). The coculture of primary human keratinocytes and allogenic dendritic cell-related cells (DC-rc) in this assay emulates the in vivo situation of the human skin. Sensitization potency of the test substances was assessed by flow cytometric analysis of the DC-rc maturation marker CD86. Determination of the concentration required to cause a half-maximal increase in CD86-expression (EC50sens) allowed a quantitative evaluation. The cytotoxicity of test substances as indicator for irritative potency was measured by 7-AAD (7-amino-actinomycin D) staining. Parabens exhibited weak (methyl-, ethyl-, propyl- and isopropylparaben) or strong (butyl-, isobutyl-, pentyl- and benzylparaben) effects, whereas phenylparaben was found to be a moderate sensitizer. Sensitization potencies of parabens correlated with side chain length. Due to a pronounced cytotoxicity, we could not estimate an EC50sens value for MI, whereas MI/MCI was classified as sensitizer and also showed cytotoxic effects. Parabens showed no (methyl- and ethylparaben) or weak irritative potencies (propyl-, isopropyl-, butyl-, isobutyl-, phenyl- and benzylparaben), only pentylparaben was rated to be irritative. Overall, we were able to demonstrate and compare the sensitizing potencies of parabens in this in vitro test. Furthermore, we showed an irritative potency for most of the preservatives. The data further support the usefulness of the LCSA for comparison of the sensitizing potencies of xenobiotics.

  15. Identification of Lilial as a fragrance sensitizer in a perfume by bioassay-guided chemical fractionation and structure-activity relationships.

    Science.gov (United States)

    Arnau, E G; Andersen, K E; Bruze, M; Frosch, P J; Johansen, J D; Menné, T; Rastogi, S C; White, I R; Lepoittevin, J P

    2000-12-01

    Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application test on the pre-sensitized patient. The chemical composition of the fractions giving a positive patch-test response and repeated open application test reactions was obtained by gas chromatography-mass spectrometry. From the compounds identified, those that contained a "structural alert" in their chemical structure, indicating an ability to modify skin proteins and thus behave as a skin sensitizer, were tested on the patient. The patient reacted positively to the synthetic fragrance p-t-butyl-alpha-methylhydrocinnamic aldehyde (Lilial), a widely used fragrance compound not present in the fragrance mix. The combination of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships seems to be a valuable tool for the investigation of contact allergy to fragrance materials.

  16. Increased capsaicin-induced secondary hyperalgesia in patients with multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Holst, Helle; Arendt-Nielsen, Lars; Mosbech, Holger;

    2011-01-01

    in experimental pain models to provoke peripheral and central sensitization. In patients with symptoms elicited by odorous chemicals capsaicin-induced secondary hyperalgesia and temporal summation were assessed as markers for abnormal central nociceptive processing together with neurogenic inflammation (flare).......the underlying cause of pathophysiological mechanisms triggering multiple chemical sensitivity (MCS) remains disputed.Recently, alterations in the central nervous system, for example,central sensitization, similar to various chronic pain disorders, have been suggested. Capsaicin is used...

  17. Keratinocyte gene expression profiles discriminate sensitizing and irritating compounds

    NARCIS (Netherlands)

    Briel, R.J. van de; Pennings, J.L.A.; Baken, K.A.; Pronk, T.E.; Boorsma, A.; Gottschalk, R.; Loveren, H. van

    2010-01-01

    Many chemicals can induce allergic contact dermatitis. Because evaluation of skin sensitizing potential by animal testing is prohibited for cosmetics, and screening of many chemicals is required within Registration, Evaluation, Authorisation and Restriction of Chemicals, urgent need exists for predi

  18. Comparison of sensitivity of quantiferon-tb gold test and tuberculin skin test in active pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Objective: To compare the sensitivity of tuberculin skin test (TST) and quantiFERON-TB gold test (QFT-G) in active pulmonary tuberculosis. Study Design: Analytical study. Place and Duration of Study: Department of Pulmonology, Fauji Foundation Hospital, Rawalpindi, from July 2011 to January 2012. Methodology: QuantiFERON-TB gold test (QFT-G) was evaluated and compared it with tuberculin skin test (TST) in 50 cases of active pulmonary tuberculosis, in whom tuberculous infection was suspected on clinical, radiological and microbiological grounds. Sensitivity was determined against positive growth for Mycobacterium tuberculosis. Results: Out of 50 cases, 43 were females and 7 were males. The mean age was 41.84 A+- 19.03 years. Sensitivity of QFT-G was 80% while that of TST was 28%. Conclusion: QFT-G has much higher sensitivity than TST for active pulmonary tuberculosis. It is unaffected by prior BCG administration and prior exposure to atypical mycobacteria. A positive QFT-G result can be an adjunct to diagnosis in patients having clinical and radiological data compatible with pulmonary tuberculosis. (author)

  19. Two-tiered keratinocyte assay: IL-18 production by NCTC2544 cells to determine the skin sensitizing capacity and an epidermal equivalent assay to determine sensitizer potency

    OpenAIRE

    Teunis, Marc; Corsini, Emanuela; Smits, Mieke; Madsen, Charlotte Bernhard; Eltze, Tobias; Ezendam, Janine; Galbiati, Valentina; Gremmer, Eric; Krul, Cyrille; Landin, Annette; Landsiedel, Robert; Pieters, Raymond; Rasmussen, Tina; Reinders, Judith; Roggen, Erwin

    2012-01-01

    At present, the identification of potentially sensitizing chemicals is carried out using animal models. However, it should be very important, both from ethical and economic point of view, to discriminate allergy and irritation events, and to classify sensitizers according to their potency, without the use of animals.The aim of the EU FP6 Integrated Project Sens-it-iv was to develop and optimize an integrated testing strategy consisting of in vitro, human cell based assays which will closely m...

  20. CPMG sequences with enhanced sensitivity to chemical exchange

    International Nuclear Information System (INIS)

    Improved relaxation-compensated Carr-Purcell-Meiboom-Gill pulse sequences are reported for studying chemical exchange of backbone 15N nuclei. In contrast to the original methods [J. P. Loria, M. Rance, and A. G. Palmer, J. Am. Chem. Soc.121, 2331-2332 (1999)], phenomenological relaxation rate constants obtained using the new sequences do not contain contributions from 1H-1H dipole-dipole interactions. Consequently, detection and quantification of chemical exchange processes are facilitated because the relaxation rate constant in the limit of fast pulsing can be obtained independently from conventional 15N spin relaxation measurements. The advantages of the experiments are demonstrated using basic pancreatic trypsin inhibitor

  1. Sensitive and fast mutation detection by solid phase chemical cleavage

    DEFF Research Database (Denmark)

    Hansen, Lise Lotte; Justesen, Just; Kruse, Torben A

    1996-01-01

    We have developed a solid phase chemical cleavage method (SpCCM) for screening large DNA fragments for mutations. All reactions can be carried out in microtiterwells from the first amplification of the patient (or test) DNA through the search for mutations. The reaction time is significantly...... reduced compared to the conventional chemical cleavage method (CCM), and even by using a uniformly labelled probe, the exact position and nature of the mutation can be revealed. The SpCCM is suitable for automatization using a workstation to carry out the reactions and a fluorescent detection-based DNA...

  2. In vivo visualization of dermal collagen fiber in skin burn by collagen-sensitive second-harmonic-generation microscopy

    Science.gov (United States)

    Tanaka, Ryosuke; Fukushima, Shu-ichiro; Sasaki, Kunihiko; Tanaka, Yuji; Murota, Hiroyuki; Matsumoto, Takeshi; Araki, Tsutomu; Yasui, Takeshi

    2013-06-01

    Optical assessment of skin burns is possible with second-harmonic-generation (SHG) microscopy due to its high sensitivity to thermal denaturation of collagen molecules. In contrast to previous studies that were performed using excised tissue specimens ex vivo, in vivo observation of dermal collagen fibers in living rat burn models with SHG microscopy is demonstrated. Changes in signal vanishing patterns in the SHG images are confirmed to be dependent on the burn degree. Comparison of the SHG images with Masson's trichrome-stained images indicated that the observed patterns were caused by the coexistence of molten and fibrous structures of dermal collagen fibers. Furthermore, a quantitative parameter for burn assessment based on the depth profile of the mean SHG intensity across the entire SHG image is proposed. These results and discussions imply a potential of SHG microscopy as a minimally invasive, highly quantitative tool for skin burn assessment.

  3. Chemical dispersants used in the Gulf of Mexico oil crisis are cytotoxic and genotoxic to sperm whale skin cells.

    Science.gov (United States)

    Wise, Catherine F; Wise, James T F; Wise, Sandra S; Thompson, W Douglas; Wise, John Pierce; Wise, John Pierce

    2014-07-01

    The 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico drew attention to the need for toxicological studies of chemical dispersants. We are still learning the effects these spills had on wildlife. Little is known about the toxicity of these substances in marine mammals. The objective of this study was to determine the toxicity of the two dispersants (Corexit 9500 and 9527). Corexit 9500 and 9527 were both cytotoxic to sperm whale skin fibroblasts. Corexit 9527 was less cytotoxic than 9500. S9 mediated metabolism did not alter cytotoxicity of either dispersant. Both dispersants were genotoxic to sperm whale skin fibroblasts; S9 mediated metabolism increased Corexit 9527 genotoxicity. PMID:24813266

  4. A link between skin and airways regarding sensitivity to fragrance products?

    DEFF Research Database (Denmark)

    Elberling, J; Linneberg, A; Mosbech, Holger Fausbøll;

    2004-01-01

    Exposure to volatile fragrances is commonplace and may be related to various eye and airway symptoms. Skin exposure to fragrances is known to cause perfume contact allergy and eczema, but it is unknown whether eye or airway symptoms elicited by fragrance products are associated with contact allergy...

  5. Quantum limit for avian magnetoreception: How sensitive can a chemical compass be?

    CERN Document Server

    Cai, Jianming; Plenio, Martin B

    2011-01-01

    The chemical compass model, based on radical pair reactions, is a fascinating idea to explain avian magnetoreception. At present, questions concerning the key ingredients responsible for the high sensitivity of a chemical compass and the possible role of quantum coherence and decoherence remain unsolved. Here, we investigate the optimized hyperfine coupling for a chemical compass in order to achieve the best magnetic field sensitivity. We demonstrate that its magnetic sensitivity limit can be further extended by simple quantum control and may benefit from additional decoherence. The present results also provide routes towards the design a biomimetic weak magnetic field sensor.

  6. Aluminum sulfate significantly reduces the skin test response to common allergens in sensitized patients

    Directory of Open Access Journals (Sweden)

    Grier Thomas J

    2006-02-01

    Full Text Available Abstract Background Avoidance of allergens is still recommended as the first and best way to prevent allergic illnesses and their comorbid diseases. Despite a variety of attempts there has been very limited success in the area of environmental control of allergic disease. Our objective was to identify a non-invasive, non-pharmacological method to reduce indoor allergen loads in atopic persons' homes and public environments. We employed a novel in vivo approach to examine the possibility of using aluminum sulfate to control environmental allergens. Methods Fifty skin test reactive patients were simultaneously skin tested with conventional test materials and the actions of the protein/glycoprotein modifier, aluminum sulfate. Common allergens, dog, cat, dust mite, Alternaria, and cockroach were used in the study. Results Skin test reactivity was significantly reduced by the modifier aluminum sulfate. Our studies demonstrate that the effects of histamine were not affected by the presence of aluminum sulfate. In fact, skin test reactivity was reduced independent of whether aluminum sulfate was present in the allergen test material or removed prior to testing, indicating that the allergens had in some way been inactivated. Conclusion Aluminum sulfate was found to reduce the in vivo allergic reaction cascade induced by skin testing with common allergens. The exact mechanism is not clear but appears to involve the alteration of IgE-binding epitopes on the allergen. Our results indicate that it may be possible to diminish the allergenicity of an environment by application of the active agent aluminum sulfate, thus producing environmental control without complete removal of the allergen.

  7. Shotgun lipidomic analysis of chemically sulfated sterols compromises analytical sensitivity

    DEFF Research Database (Denmark)

    Casanovas, Albert; Hannibal-Bach, Hans Kristian; Jensen, Ole Nørregaard;

    2014-01-01

    Fourier transform mass spectrometry (FTMS) for identification and quantification of lipid species [6]. Shotgun lipidomics affords extensive lipidome coverage by combining the analysis of lipid extracts in positive and negative ion mode [1, 3]. Notably, sterols such as cholesterol and ergosterol exhibit...... low ionization efficiency in ESI [7]. For this reason, chemical derivatization procedures including acetylation [8] or sulfation [9] are commonly implemented to facilitate ionization, detection and quantification of sterols for global lipidome analysis [1-3, 10]....

  8. NOTE: Initial evaluation of acoustic reflectors for the preservation of sensitive abdominal skin areas during MRgFUS treatment

    Science.gov (United States)

    Gorny, Krzysztof R.; Chen, Shigao; Hangiandreou, Nicholas J.; Hesley, Gina K.; Woodrum, David A.; Brown, Douglas L.; Felmlee, Joel P.

    2009-04-01

    During MR-guided focused ultrasound (MRgFUS) treatments of uterine fibroids using ExAblate®2000 (InSightec, Haifa, Israel), individual tissue ablations are performed extracorporeally through the patient's abdomen using an annular array FUS transducer embedded within the MR table. Ultrasound intensities in the near field are below therapeutic levels and, under normal conditions, heating of the patient skin is minimal. However, increased absorption of ultrasound energy within sensitive skin areas or areas with differing acoustic properties, such as scars, may lead to skin burns and therefore these areas must be kept outside the near field of the FUS beam. Depending on their location and size the sensitive areas may either obstruct parts of the fibroid from being treated or prevent the entire MRgFUS treatment altogether. The purpose of this work is to evaluate acoustic reflector materials that can be applied to protect skin and the underlying sensitive areas. Reflection coefficients of cork (0.88) and foam (0.91) based materials were evaluated with a hydrophone. An ExAblate 2000 MRgFUS system was used to simulate clinical treatment with discs of reflector materials placed in a near field underneath a gel phantom. MR thermometry was used to monitor temperature elevations as well as the integrity of the focal spot. The phantom measurements showed acoustic shadow zones behind the reflectors with zone depths changing between 7 and 27 mm, for reflector disc diameters increasing from 10 to 30 mm (40 mm diameter discs completely blocked the FUS beam at the depth evaluated). The effects on thermal lesions due to the presence of the reflectors in the FUS beam were found to diminish with decreasing disc diameter and increasing sonication depth. For a 20 mm diameter disc and beyond 50 mm sonication depth, thermal lesions were minimally affected by the presence of the disc. No heating was observed on the skin side of the foam reflectors, as confirmed by measurements performed

  9. A Chemical-Medical Mystery: Gold Jewelry and Black Marks on Skin

    Science.gov (United States)

    Kebbekus, Barbara B.

    2000-10-01

    Gold jewelry at times makes a black mark or smudge on skin. This may be caused by abrasive powders on the skin (e.g. zinc oxide) but the phenomenon may also be caused by other skin conditions, possibly the presence of chloride ion, acidity, or sulfur-containing amino acids. Some anecdotal evidence is published, but properly designed studies to clarify the actual causes are not available.

  10. Chemical sensitivity of graphene edges decorated with metal nanoparticles.

    Science.gov (United States)

    Vedala, Harindra; Sorescu, Dan C; Kotchey, Gregg P; Star, Alexander

    2011-06-01

    Graphene is a novel two-dimensional nanomaterial that holds great potential in electronic and sensor applications. By etching the edges to form nanoribbons or introducing defects on the basal plane, it has been demonstrated that the physical and chemical properties of graphene can be drastically altered. However, the lithographic or chemical techniques required to reliably produce such nanoribbons remain challenging. Here, we report the fabrication of nanosensors based on holey reduced graphene oxide (hRGO), which can be visualized as interconnected graphene nanoribbons. In our method, enzymatic oxidation generated holes within the basal plane of graphene oxide, and after reduction with hydrazine, hRGO was formed. When decorated with Pt nanoparticles, hRGO exhibited a large and selective electronic response toward hydrogen gas. By combining experimental results and theoretical modeling, we propose that the increased edge-to-plane ratio, oxygen moieties, and Pt nanoparticle decoration were responsible for the observed gas sensing with hRGO nanostructures. PMID:21591652

  11. Sensitization to Aeroallergens in Patients with Respiratory Allergies Based on Skin-Prick Test Results

    OpenAIRE

    G Bejtullahu; Karahoda, N; H Pupovci; Lokaj-Berisha, V; Berisha, N; Lumezi, B; Ahmetaj, L

    2012-01-01

    Background: The aim of this study was to identify the most common aeroallergens in patients with asthma and rhinitis. Methods: The study enrolled 102 participants including 64 patients with respiratory allergies (among them 15 were clinically diagnosed as asthma patients, 41 with rhinitis, 8 were both) and 38 healthy controls. All of participants were subject of skin prick tests (SPT) with series of common allergenic extracts. Sera from all participants were tested for total IgE and eosinophi...

  12. Impaired skin regeneration and remodeling after cutaneous injury and chemically induced hyperplasia in taps-transgenic mice.

    Science.gov (United States)

    Hildenbrand, Maike; Rhiemeier, Verena; Hartenstein, Bettina; Lahrmann, Bernd; Grabe, Niels; Angel, Peter; Hess, Jochen

    2010-07-01

    Recently, we identified an AP-1-dependent target gene in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated mouse back skin, which encodes a retroviral-like aspartic proteinase (Taps/Asprv1). Taps expression was detected almost exclusively in stratified epithelia of mouse embryos and adult tissues, and enhanced protein levels were present in several non-neoplastic human skin disorders, implicating a crucial role for differentiation and homeostasis of multilayered epithelia. Here, we generated a mouse model in which Taps transgene expression is under the control of the human ubiquitin C promoter (UBC-Taps). Although no obvious phenotype was observed in normal skin development and homeostasis, these mice showed a significant delay in cutaneous wound closure compared with control animals. Shortly after re-epithelialization, we found an increase in keratinocytes in the stratum granulosum, which express Filaggrin, a late differentiation marker. A hypergranulosum-like phenotype with increased numbers of Filaggrin-positive keratinocytes was also observed in UBC-Taps mice after administration of TPA. In summary, these data show that aberrant Taps expression causes impaired skin regeneration and skin remodeling after cutaneous injury and chemically induced hyperplasia. PMID:20237492

  13. Chemical composition and antioxidant-prooxidant potential of a polyphenolic extract and a proanthocyanidin-rich fraction of apple skin.

    Science.gov (United States)

    Mendoza-Wilson, Ana María; Castro-Arredondo, Sergio Ivan; Espinosa-Plascencia, Angélica; Robles-Burgueño, María Del Refugio; Balandrán-Quintana, René Renato; Bermúdez-Almada, María Del Carmen

    2016-02-01

    The apple is a food rich in diverse classes of polyphenols (PP), among which the proanthocyanidins (PCs), which are primarily concentrated in the skin, are one of the most abundant. These compounds are of considerable interest for their possible positive health effects because of their antioxidant properties. However, depending on the classes of PP present (chemical composition) and their relative concentrations in the apple skin, their antioxidant effects vary and some of their components can even generate prooxidant effects. This work determined the chemical composition and antioxidant-prooxidant potential of a polyphenolic extract (PPE) and a proanthocyanidin-rich fraction (PRF) of apple skin, along with the contribution of their most abundant individual compounds, based on their copper chelating ability, ease in reducing peroxidase-generated free radicals and TEAC (Trolox-Equivalent Antioxidant Capacity) assay. For this purpose, chromatographic and colorimetric methods were used. The majority compounds identified in PPE were flavan-3-ols (44.58%), flavonols (42.89%) and dihydrochalcones (11.60%). In PRF, we detected monomers and oligomers from dimers to heptamers, which were composed of 97% (-)-epicatechin and 3% (+)-catechin. The antioxidant potential was notably higher in PRF than in PPE. The (-)-epicatechin monomer and the procyanidin B2 dimer showed more ease in reducing peroxidase-generated free radicals compared to other compounds of the apple skin, whereas phloridzin dihydrochalcone produced prooxidant effects. PMID:27441252

  14. 78 FR 68076 - Request for Information on Alternative Skin Sensitization Test Methods and Testing Strategies and...

    Science.gov (United States)

    2013-11-13

    .... NICEATM collaboration with academic scientists to develop and evaluate chemical structure--activity... assessment by government organizations including the Organisation for Economic Co-operation and...

  15. Risk of sensitization in healthy adults following repeated administration of rdESAT-6 skin test reagent by the Mantoux injection technique

    DEFF Research Database (Denmark)

    Lillebaek, Troels; Bergstedt, Winnie; Tingskov, Pernille N;

    2009-01-01

    Limited specificity of the tuberculin skin test incited the development of the intradermal Mycobacterium tuberculosis-specific rdESAT-6 skin test. Animal studies have shown, however, that there is a possible risk of sensitization when repeated injections of rdESAT-6 are given. The aim of this phase...... 31 (3%) volunteers showed a positive skin reaction (sensitization) upon a second injection of rdESAT-6 after 28days and an increased IFN-gamma response to ESAT-6. For 7 (23%) of the volunteers, local adverse reactions related to the product were registered, but all reactions were mild and predictable....... In conclusion, repeated injections of the rdESAT-6 skin test reagent are safe, and sensitization occurs at a low rate, especially if the time span between succeeding doses is wide....

  16. Chemical Vapour Deposition of Gas Sensitive Metal Oxides

    Directory of Open Access Journals (Sweden)

    Stella Vallejos

    2016-03-01

    Full Text Available This article presents a review of recent research efforts and developments for the fabrication of metal-oxide gas sensors using chemical vapour deposition (CVD, presenting its potential advantages as a materials synthesis technique for gas sensors along with a discussion of their sensing performance. Thin films typically have poorer gas sensing performance compared to traditional screen printed equivalents, attributed to reduced porosity, but the ability to integrate materials directly with the sensor platform provides important process benefits compared to competing synthetic techniques. We conclude that these advantages are likely to drive increased interest in the use of CVD for gas sensor materials over the next decade, whilst the ability to manipulate deposition conditions to alter microstructure can help mitigate the potentially reduced performance in thin films, hence the current prospects for use of CVD in this field look excellent.

  17. IgE Sensitization Patterns to Commonly Consumed Foods Determined by Skin Prick Test in Korean Adults.

    Science.gov (United States)

    Kim, Sung Ryeol; Park, Hye Jung; Park, Kyung Hee; Lee, Jae-Hyun; Park, Jung-Won

    2016-08-01

    Offending food allergens can vary with regional preferences in food consumption. In this study, we analysed sensitization rates to commonly consumed foods in Korean adults suspected of having food allergy. One hundred and thirty four subjects underwent a skin prick test (SPT) with 55 food allergens, of which 13 were made by our laboratory and the rest were commercially purchased. Of the 134 patients, 73 (54.5%) were sensitized to one or more food allergens. Sensitization to chrysalis was detected most frequently, at a rate of 25.4%. Sensitization rates to other food allergens were as follows: maize grain (13.4%), shrimp (11.9%), almond (11.1%), wheat flour (8.2%), lobster (8.2%), buckwheat (8.2%), mackerel (5.2%), pollack (5.2%), halibut (4.5%), peanut (4.5%), anchovy (4.4%), squid (3.7%), saury (3.0%), common eel (3.0%), yellow corvina (3.0%), hairtail (2.2%), octopus (2.2%), and others. In addition to well-known food allergens, sensitivity to mackerel, chrysalis, pollack, and halibut, which are popular foods in Korea, was observed at high rates in Korean adults. We suggest that the SPT panel for food allergy in Korea should include these allergens. PMID:27478328

  18. IgE Sensitization Patterns to Commonly Consumed Foods Determined by Skin Prick Test in Korean Adults

    Science.gov (United States)

    2016-01-01

    Offending food allergens can vary with regional preferences in food consumption. In this study, we analysed sensitization rates to commonly consumed foods in Korean adults suspected of having food allergy. One hundred and thirty four subjects underwent a skin prick test (SPT) with 55 food allergens, of which 13 were made by our laboratory and the rest were commercially purchased. Of the 134 patients, 73 (54.5%) were sensitized to one or more food allergens. Sensitization to chrysalis was detected most frequently, at a rate of 25.4%. Sensitization rates to other food allergens were as follows: maize grain (13.4%), shrimp (11.9%), almond (11.1%), wheat flour (8.2%), lobster (8.2%), buckwheat (8.2%), mackerel (5.2%), pollack (5.2%), halibut (4.5%), peanut (4.5%), anchovy (4.4%), squid (3.7%), saury (3.0%), common eel (3.0%), yellow corvina (3.0%), hairtail (2.2%), octopus (2.2%), and others. In addition to well-known food allergens, sensitivity to mackerel, chrysalis, pollack, and halibut, which are popular foods in Korea, was observed at high rates in Korean adults. We suggest that the SPT panel for food allergy in Korea should include these allergens. PMID:27478328

  19. Evaluation of human skin tests for potential dermal irritant and contact sensitizing products: a position paper

    NARCIS (Netherlands)

    Loveren H van; Jong WH de; Garssen J; LPI

    1998-01-01

    Prediction of human cutaneous irritation and sensitization in view of hazard identification has primarily relied on the use of laboratory animals. Such studies in laboratory animals have been very instrumental in the detection of potential contact sensitizing agents. There are however many uncertain

  20. An elevated pro-inflammatory cytokine profile in multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Elberling, J.; Pedersen, Susanne Brix;

    2014-01-01

    BackgroundMultiple chemical sensitivity (MCS) is a medically unexplained condition characterized by reports of recurrent unspecific symptoms attributed to exposure to low levels of common volatile chemicals. The etiology of MCS is poorly understood, but dysregulation of the immune system has been...

  1. Conducting polymer nanofibers for high sensitivity detection of chemical analytes.

    Science.gov (United States)

    Kumar, Abhishek; Leshchiner, Ignaty; Nagarajan, Subhalakshmi; Nagarajan, Ramaswamy; Kumar, Jayant

    2008-03-01

    Possessing large surface area materials is vital for high sensitivity detection of analyte. We report a novel, inexpensive and simple technique to make high surface area sensing interfaces using electrospinning. Conducting polymers (CP) nanotubes were made by electrospinning a solution of a catalyst (ferric tosylate) along with poly (lactic acid), which is an environment friendly biodegradable polymer. Further vapor deposition polymerization of the monomer ethylenedioxy thiophene (EDOT) on the nanofiber surface yielded poly (EDOT) covered fibers. X-ray photo electron spectroscopy (XPS) study reveals the presence of PEDOT predominantly on the surface of nanofibers. Conducting nanotubes had been received by dissolving the polymer in the fiber core. By a similar technique we had covalently incorporated fluorescent dyes on the nanofiber surface. The materials obtained show promise as efficient sensing elements. UV-Vis characterization confirms the formation of PEDOT nanotubes and incorporation of chromophores on the fiber surface. The morphological characterization was carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  2. [Indoor air and human health--sick house syndrome and multiple chemical sensitivity].

    Science.gov (United States)

    Ando, Masanori

    2002-01-01

    The number of complaints about the quality of indoor air has increased during the past two decades. These complaints have been frequent enough that the term "Sick House Syndrome or Sick Building Syndrome" and "Multiple Chemical Sensitivity" has been coined. Complaints are likely related to the increased use of synthetic organic materials in house, furnishing, and consumer products; and the buildings, furnishings, and consumer products; and the decreased ventilation for energy conservation in homes. Approximately thousand volatile chemicals have been identified in indoor air. The main sources of these chemicals are house materials, combustion fumes, cleaning compounds, and paints or stains. Exposure to high levels of these emissions and to others, coupled with the fact that most people spend more time indoors than outdoors, raises the possibility that the risk to human health from indoor air pollution may be potentially greater than the risk posed from outdoor pollutants. The complaints most frequently voiced with respect to Sick House Syndrome are irritations of the eye, nose, and throat; cough and hoarseness of voice; headache and mental fatigue. The syndrome of multiple chemical sensitivities is controversial subject with increasing impact on the field of indoor air quality. The controversy surrounding Multiple Chemical Sensitivity includes its definition, theories of etiology and pathogenesis, diagnostic, and life style. Multiple Chemical Sensitivity is considered the hypothesis that is a disease caused by exposure to many chemically distinct environmental substances at very low.

  3. Demonstration of tyrosinase in the vitiligo skin of human beings by a sensitive fluorometric method as well as by 14C(U)-L-tyrosine incorporation into melanin

    Energy Technology Data Exchange (ETDEWEB)

    Husain, I.; Vijayan, E.; Ramaiah, A.; Pasricha, J.S.; Madan, N.C.

    1982-03-01

    Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. The tyrosine activity in the vitiligo skin was about 4 to 37% of corresponding normal skin. The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. The enzyme from vitiligo and normal skin was severely inhibited by substance(s) of low molecular weight. The enzyme exhibits a lag of about 4 hr in the absence of added beta 3,4-dihydroxyphenylalanine and 1 hr in presence of 5 microM dopa. Tyrosinase from the normal and vitiligo skin was inhibited by excess concentration of tyrosine. The homogenates from vitiligo skin could synthesize melanin from C14(U)-L-Tyrosine. The rate of tyrosine incorporation into melanin by the epidermal homogenates is increased by 3,4-dihydroxyphenylalanine (dopa) disproportionate to its effect on tyrosinase activity. Based on the data presented in this paper it is concluded that melanocytes are present in the vitiligo skin. A tentative hypothesis is put forward to explain the lack of melanin synthesis by the vitiligo skin under in vivo conditions, although melanocytes are present.

  4. Capsaicin-induced neurogenic inflammation in the skin in patients with symptoms induced by odorous chemicals

    DEFF Research Database (Denmark)

    Holst, Helle; Arendt-Nielsen, Lars; Mosbech, Holger;

    2011-01-01

    Intradermal injection of capsaicin induces the axonal release of neuropeptides, vasodilatation and flare, e.g. neurogenic inflammation. The spatial profile of neurogenic inflammation in the skin has been studied in various experimental models. Polarization spectroscopy imaging introduced recently...

  5. Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.

    2002-10-28

    Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.

  6. Mouse allergen-specific immunoglobulin G4 and risk of mouse skin test sensitivity

    NARCIS (Netherlands)

    E.C. Matsui; G.B. Diette; E.J.M. Krop; R.C. Aalberse; A.L. Smith; P.A. Eggleston

    2006-01-01

    Background High serum levels of cat-specific IgG and IgG4 are associated with protection against allergic sensitization to cat, but whether this association applies to other animal allergens remains unclear. Objective To determine if high levels of mouse-specific IgG and IgG4 are associated with a d

  7. Quantification of Eosinophilic Granule Protein Deposition in Biopsies of Inflammatory Skin Diseases by Automated Image Analysis of Highly Sensitive Immunostaining

    Directory of Open Access Journals (Sweden)

    Peter Kiehl

    1999-01-01

    Full Text Available Eosinophilic granulocytes are major effector cells in inflammation. Extracellular deposition of toxic eosinophilic granule proteins (EGPs, but not the presence of intact eosinophils, is crucial for their functional effect in situ. As even recent morphometric approaches to quantify the involvement of eosinophils in inflammation have been only based on cell counting, we developed a new method for the cell‐independent quantification of EGPs by image analysis of immunostaining. Highly sensitive, automated immunohistochemistry was done on paraffin sections of inflammatory skin diseases with 4 different primary antibodies against EGPs. Image analysis of immunostaining was performed by colour translation, linear combination and automated thresholding. Using strictly standardized protocols, the assay was proven to be specific and accurate concerning segmentation in 8916 fields of 520 sections, well reproducible in repeated measurements and reliable over 16 weeks observation time. The method may be valuable for the cell‐independent segmentation of immunostaining in other applications as well.

  8. Gas chemical sensitivity of a CMOS MEMS cantilever functionalized via evaporation driven assembly

    International Nuclear Information System (INIS)

    This work demonstrates an electrostatically actuated resonant microcantilever fabricated in a complementary metal oxide semiconductor process and functionalized with a chemically sorbent polymer layer for the detection of volatile organic compounds. Deposition of the chemically sorbent layer is controlled through evaporation-driven assembly. Analytical and finite element analysis models of the deposited polymer layer on the microcantilever resonant frequency and mass sensitivity are presented. Fabrication of the chemical sensor, including a description of polymer deposition through evaporation-driven assembly within a capillary, is detailed. The completely functionalized resonator demonstrates a limit of detection of 1.6 ppm for toluene. An optimal polymer sensitive layer deposition of 42% of the total beam length is measured from frequency instability and sensitivity tests. (paper)

  9. Tactile surface classification for limbed robots using a pressure sensitive robot skin

    International Nuclear Information System (INIS)

    This paper describes an approach to terrain identification based on pressure images generated through direct surface contact using a robot skin constructed around a high-resolution pressure sensing array. Terrain signatures for classification are formulated from the magnitude frequency responses of the pressure images. The initial experimental results for statically obtained images show that the approach yields classification accuracies >98%. The methodology is extended to accommodate the dynamic pressure images anticipated when a robot is walking or running. Experiments with a one-legged hopping robot yield similar identification accuracies ≈99%. In addition, the accuracies are independent with respect to changing robot dynamics (i.e., when using different leg gaits). The paper further shows that the high-resolution capabilities of the sensor enables similarly textured surfaces to be distinguished. A correcting filter is developed to accommodate for failures or faults that inevitably occur within the sensing array with continued use. Experimental results show using the correcting filter can extend the effective operational lifespan of a high-resolution sensing array over 6x in the presence of sensor damage. The results presented suggest this methodology can be extended to autonomous field robots, providing a robot with crucial information about the environment that can be used to aid stable and efficient mobility over rough and varying terrains. (paper)

  10. Detection of potentially skin sensitizing hydroperoxides of linalool in fragranced products.

    Science.gov (United States)

    Kern, Susanne; Dkhil, Hafida; Hendarsa, Prisca; Ellis, Graham; Natsch, Andreas

    2014-10-01

    On prolonged exposure to air, linalool can form sensitizing hydroperoxides. Positive hydroperoxide patch tests in dermatitis patients have frequently been reported, but their relevance has not been established. Owing to a lack of analytical methods and data, it is unclear from which sources the public might be exposed to sufficient quantities of hydroperoxides for induction of sensitization to occur. To address this knowledge gap, we developed analytical methods and performed stability studies for fine fragrances and deodorants/antiperspirants. In parallel, products recalled from consumers were analysed to investigate exposure to products used in everyday life. Liquid chromatography-mass spectrometry with high mass resolution was found to be optimal for the selective and sensitive detection of the organic hydroperoxide in the complex product matrix. Linalool hydroperoxide was detected in natural linalool, but the amount was not elevated by storage in a perfume formulation exposed to air. No indication of hydroperoxide formation in fine fragrances was found in stability studies. Aged fine fragrances recalled from consumers contained a geometric mean linalool concentration of 1,888 μg/g and, corrected for matrix effects, linalool hydroperoxide at a concentration of around 14 μg/g. In antiperspirants, we detected no oxidation products. In conclusion, very low levels of linalool hydroperoxide in fragranced products may originate from raw materials, but we found no evidence for oxidation during storage of products. The levels detected are orders of magnitude below the levels inducing sensitization in experimental animals, and these results therefore do not substantiate a causal link between potential hydroperoxide formation in cosmetics and positive results of patch tests.

  11. Phototoxicity of Phenylenediamine Hair Dye Chemicals in Salmonella typhimurium TA102 and Human Skin Keratinocytes

    OpenAIRE

    Yu, Hongtao; Mosley-Foreman; Choi, Jaehwa; Wang, Shuguang

    2008-01-01

    Phenylenediamines (PD) are dye precursors used to manufacture hair dyes. The three PDs, 1,2-, 1,3-, and 1,4-PD and three chlorinated PDs, 4-chloro-1,2-PD, 4-chloro-1,3- PD, and 4,5-dichloro-1,2-PD were studied for their mutagenic effect in Salmonella typhimurium TA 102, cytotoxicity in human skin keratinocyte cells, and for DNA cleavage. The results show that all six compounds are not toxic/mutagenic in TA 102 bacteria or skin cells, and do not cause DNA cleavage in ΦX 174 phage DNA. If the s...

  12. Resonant absorption of a chemically sensitive layer based on waveguide gratings

    OpenAIRE

    Davoine, Laurent; Paeder, Vincent; Basset, Guillaume; Schnieper, Marc; Herzig, Hans Peter

    2013-01-01

    A colorimetric sensor providing a direct visual indication of chemical contamination was developed. The sensor is a combination of a chemically sensitive dye layer and a resonant waveguide grating. Enhancement of the light absorption by the photonic structure can be clearly seen. The detection is based on the color change of the reflected light after exposure to a gas or a liquid. Low-cost fabrication and compatibility with environments where electricity cannot be used make this device very a...

  13. TIMES-SS - A promising tool for the assessment of skin sensitization hazard. A characterization with respect to the OECD validation principles for (Q)SARs and an external evaluation for predictivity

    DEFF Research Database (Denmark)

    Patlewicz, Grace; Dimitrov, Sabcho D.; Low, Lawrence K.;

    2007-01-01

    The TImes MEtabolism Simulator platform used for predicting Skin Sensitization (TIMES-SS) is a hybrid expert system that was developed at Bourgas University using funding and data from a Consortium comprising industry and regulators. The model was developed with the aim of minimizing animal testing...... and to be scientifically valid in accordance with the OECD principles for (Q)SAR validation. TIMES-SS encodes structure-toxicity and structure-skin metabolism relationships through a number of transformations, some of which are underpinned by mechanistic 3D QSARs. Here, we describe the extent to which the five OECD...... principles are met and in particular the results from an external evaluation exercise that was recently carried out. As part of this exercise, data were generated for 40 new chemicals in the murine local lymph node assay (LLNA) and then compared with predictions made by TIMES-SS. The results were promising...

  14. Study on the variation in X-ray sensitivity of human diploid skin fibroblasts

    International Nuclear Information System (INIS)

    9 cell strains derived from patients with Huntington's disease and 9 from age- and sex-matched controls were investigated for X-ray sensitivity. No differences in radiosensitivity were observed for the two groups. The two groups taken together reveal a dependence of radiosensitivity on intrinsic cloning efficiency which in turn correlates with donor age. A difference in radiosensitivity between males and females is also indicated although at the borderline of significance. As a parameter for radiosensitivity the dose needed to obtain 0.1% survival appears superior to the Do. (orig.)

  15. Reduction of Salmonella on chicken meat and chicken skin by combined or sequential application of lytic bacteriophage with chemical antimicrobials.

    Science.gov (United States)

    Sukumaran, Anuraj T; Nannapaneni, Rama; Kiess, Aaron; Sharma, Chander Shekhar

    2015-08-17

    The effectiveness of recently approved Salmonella lytic bacteriophage preparation (SalmoFresh™) in reducing Salmonella in vitro and on chicken breast fillets was examined in combination with lauric arginate (LAE) or cetylpyridinium chloride (CPC). In another experiment, a sequential spray application of this bacteriophage (phage) solution on Salmonella inoculated chicken skin after a 20s dip in chemical antimicrobials (LAE, CPC, peracetic acid, or chlorine) was also examined in reducing Salmonella counts on chicken skin. The application of phage in combination with CPC or LAE reduced S. Typhimurium, S. Heidelberg, and S. Enteritidis up to 5 log units in vitro at 4 °C. On chicken breast fillets, phage in combination with CPC or LAE resulted in significant (pSalmonella ranging from 0.5 to 1.3 log CFU/g as compared to control up to 7 days of refrigerated storage. When phage was applied sequentially with chemical antimicrobials, all the treatments resulted in significant reductions of Salmonella. The application of chlorine (30 ppm) and PAA (400 ppm) followed by phage spray (10(9)PFU/ml) resulted in highest Salmonella reductions of 1.6-1.7 and 2.2-2.5l og CFU/cm(2), respectively. In conclusion, the surface applications of phage in combination with LAE or CPC significantly reduced Salmonella counts on chicken breast fillets. However, higher reductions in Salmonella counts were achieved on chicken skin by the sequential application of chemical antimicrobials followed by phage spray. The sequential application of chlorine, PAA, and phage can provide additional hurdles to reduce Salmonella on fresh poultry carcasses or cut up parts.

  16. Proteomic Alterations in B Lymphocytes of Sensitized Mice in a Model of Chemical-Induced Asthma

    OpenAIRE

    Steven Haenen; Jeroen A.J. Vanoirbeek; Vanessa De Vooght; Liliane Schoofs; Benoit Nemery; Elke Clynen; Hoet, Peter H. M.

    2015-01-01

    Introduction and Aim The role of B-lymphocytes in chemical-induced asthma is largely unknown. Recent work demonstrated that transferring B lymphocytes from toluene diisocyanate (TDI)-sensitized mice into naïve mice, B cell KO mice and SCID mice, triggered an asthma-like response in these mice after a subsequent TDI-challenge. We applied two-dimensional difference gel electrophoresis (2D-DIGE) to describe the “sensitized signature” of B lymphocytes comparing TDI-sensitized mice with control mi...

  17. Chemically induced skin carcinogenesis in mice and its prevention by Aegle marmelos (an Indian medicinal plant) fruit extract.

    Science.gov (United States)

    Agrawal, Annapurna; Jahan, Swafiya; Goyal, Pradeep Kumar

    2011-01-01

    This study assessed the chemopreventive potential of the Aegle marmelos plant on mouse skin tumorigenesis initiated by 7,12-dimethylbenz(a)anthracene (DMBA) and promoted by croton oil. A significant reduction in tumor incidence, tumor burden, tumor multiplicity, and the cumulative number of papillomas, along with a significant increase in the average latent period, was recorded in mice treated orally with A. marmelos extract (AME) at peri - and post-initiation phases (i.e., 7 days before DMBA application and continued until the end of the experiment) of papillomagenesis as compared with the carcinogen-treated controls. Furthermore, a significant increase in catalase activity, reduced glutathione and total proteins, and a depleted level of lipid peroxidation were observed in liver and skin of AME-treated animals as compared with the carcinogen-treated controls. Thus, the oral administration of AME, at a dose of 50 mg/kg body wt per day per animal, was found to be significantly effective in reducing skin tumors against chemical carcinogenesis in mice. PMID:22126618

  18. Evolution of metastasis revealed by mutational landscapes of chemically induced skin cancers | Office of Cancer Genomics

    Science.gov (United States)

    Human tumors show a high level of genetic heterogeneity, but the processes that influence the timing and route of metastatic dissemination of the subclones are unknown. Here we have used whole-exome sequencing of 103 matched benign, malignant and metastatic skin tumors from genetically heterogeneous mice to demonstrate that most metastases disseminate synchronously from the primary tumor, supporting parallel rather than linear evolution as the predominant model of metastasis.

  19. Sensitivity analysis of silicon nanowire chemical sensor based on its geometry and the operating temperature

    Science.gov (United States)

    Jayachandran Nair, Deepthi

    Silicon Nano Wires (SiNW) have been used in recent times as major building block in various nano devices like sensors, FETs etc. SiNW devices have also manifested many advantages over nano tube (NT) devices such as their fabrication in today's silicon world. Chemical sensor based on SiNW changes its conductivity when the target molecules are captured by the receptors spread across the nano wire (NW). Chemical sensitivity, which is defined as the change in conductance, is analyzed analytically to see how it is affected by different parameters. The sensitivity of the sensor based on the length of the SiNW is verified from previous works and the temperature which has not been considered before as an important parameter in the sensor performance are taken into account to see how it affects the sensitivity of the sensor.

  20. Ultrafast multidimensional Laplace NMR for a rapid and sensitive chemical analysis

    Science.gov (United States)

    Ahola, Susanna; Zhivonitko, Vladimir V.; Mankinen, Otto; Zhang, Guannan; Kantola, Anu M.; Chen, Hsueh-Ying; Hilty, Christian; Koptyug, Igor V.; Telkki, Ville-Veikko

    2015-09-01

    Traditional nuclear magnetic resonance (NMR) spectroscopy relies on the versatile chemical information conveyed by spectra. To complement conventional NMR, Laplace NMR explores diffusion and relaxation phenomena to reveal details on molecular motions. Under a broad concept of ultrafast multidimensional Laplace NMR, here we introduce an ultrafast diffusion-relaxation correlation experiment enhancing the resolution and information content of corresponding 1D experiments as well as reducing the experiment time by one to two orders of magnitude or more as compared with its conventional 2D counterpart. We demonstrate that the method allows one to distinguish identical molecules in different physical environments and provides chemical resolution missing in NMR spectra. Although the sensitivity of the new method is reduced due to spatial encoding, the single-scan approach enables one to use hyperpolarized substances to boost the sensitivity by several orders of magnitude, significantly enhancing the overall sensitivity of multidimensional Laplace NMR.

  1. LSENS, a general chemical kinetics and sensitivity analysis code for gas-phase reactions: User's guide

    Science.gov (United States)

    Radhakrishnan, Krishnan; Bittker, David A.

    1993-01-01

    A general chemical kinetics and sensitivity analysis code for complex, homogeneous, gas-phase reactions is described. The main features of the code, LSENS, are its flexibility, efficiency and convenience in treating many different chemical reaction models. The models include static system, steady, one-dimensional, inviscid flow, shock initiated reaction, and a perfectly stirred reactor. In addition, equilibrium computations can be performed for several assigned states. An implicit numerical integration method, which works efficiently for the extremes of very fast and very slow reaction, is used for solving the 'stiff' differential equation systems that arise in chemical kinetics. For static reactions, sensitivity coefficients of all dependent variables and their temporal derivatives with respect to the initial values of dependent variables and/or the rate coefficient parameters can be computed. This paper presents descriptions of the code and its usage, and includes several illustrative example problems.

  2. Low sensitivity of type VII collagen enzyme-linked immunosorbent assay in epidermolysis bullosa acquisita : serration pattern analysis on skin biopsy is required for diagnosis

    NARCIS (Netherlands)

    Terra, J. B.; Jonkman, M. F.; Diercks, G. F. H.; Pas, H. H.

    2013-01-01

    BackgroundThe type VII collagen (coll VII) enzyme-linked immunosorbent assay (ELISA) has been reported to have high sensitivity (>93%) and specificity (>96%) for diagnosing epidermolysis bullosa acquisita (EBA) in patients who are seropositive on indirect immunofluorescence on salt-split skin (SSS).

  3. Application of the acquired knowledge and implementation of the Sens-it-iv toolbox for identification and classification of skin and respiratory sensitizers.

    Science.gov (United States)

    Roggen, Erwin L

    2013-04-01

    The contribution of the Sens-it-iv project to the reduction and replacement of animal experimentation is 3-fold. The funding of basic research has expanded the existing scientific knowledge thereby strengthening the understanding of the cellular and molecular mechanisms driving skin and respiratory sensitization. Examples are given on how a better understanding was used to improve existing test concepts. This knowledge was also applied to develop novel test systems. While some of test systems did not reach sufficient maturity for being considered for pre-validation others did and entered into the Sens-it-iv toolbox. In the process, developments outside the Sens-it-iv orbit were carefully followed and assessed in order to avoid duplication and to assure synergy between the ongoing activities (e.g. Cosmetics Europe Task Force for Sensitization). Tests from the Sens-it-iv toolbox were submitted to the European Reference Laboratory for Alternative Methods (EuRL-ECVAM) to initiate the rigid procedures for regulatory acceptance by national and international authorities. In spite of not being validated yet, selected tests were already applied in a weight-of-evidence approach in the context of REACH. Furthermore, several chemical, pharmaceutical, cosmetic and consumer product companies are currently assessing selected tests and testing strategies for their value as tools for screening and hazard identification using in house compounds and mixtures. The main points of concern related to transfer to and implementation by industry were cost, through-put and applicability domain, rather than regulatory acceptance. These issues are currently addressed in applied research projects which are financially supported by individual companies, or consortia of companies, representing the various industry sectors. PMID:23063875

  4. [Sensitivity of Pseudomonas chlororaphis to antibiotics and chemical tools of plant protection].

    Science.gov (United States)

    Shepelevich, V V; Kiprianova, E A; Iaroshenko, L V; Avdeeva, L V

    2012-01-01

    Examination of sensitivity of 10 Pseudomonas chlororaphis strains belonging to different subspecies to 54 antibiotics has shown that all studied representatives of Pchlororaphis subsp. chlororaphis, P. chlororaphis subsp. aureofaciens and Pchlororaphis subsp. aurantiaca were sensitive to aminoglycoside antibiotics and fluoroquinolones derivatives. Only part of studied strains has shown sensitivity to some beta-lactam antibiotics, imipeneme and meropeneme. In contrast to representatives of two other subspecies both strains of P. chlororaphis subsp. chlororaphis proved to be sensitive to chlortetracycline and cefepime that allows to consider this difference as the characteristic useful for differentiation. All studied P. chlororaphis strains were resistant to chemical fungicides (Scor and Svitch) and the insect growth regulators (Match, Lufox, Engio, Actellik). Resistance of bacteria to these herbicides gives evidence that their combined use is possible.

  5. Impact of self-reported multiple chemical sensitivity on everyday life: a qualitative study

    DEFF Research Database (Denmark)

    Skovbjerg, Sine; Brorson, Stig; Rasmussen, Alice;

    2009-01-01

    BACKGROUND: Multiple chemical sensitivity (MCS) is a descriptive term covering symptoms attributed to exposure to common airborne chemicals. There are no internationally accepted criteria, but it has been suggested that MCS is a chronic and disabling condition. However, details of the impact of M...... on individual consequences and the social and psychological factors that may be associated with MCS is needed in order to add to our understanding of this condition and to the provision of more satisfactory healthcare......., a duration of MCS of at least 1 year, and with different occupational conditions. RESULTS: MCS may severely influence different aspects of everyday life, including lifestyle, social relations, and occupational conditions. Avoiding common airborne chemicals was the most prevalent coping strategy, which...... implied creating a chemical-free living space and limiting social activities. Experiences with healthcare management were overall reported as negative in terms of not receiving acknowledgement of the reported symptoms. CONCLUSIONS: MCS may have serious implications for daily functioning. Further research...

  6. Chemopreventive potential of Annona muricata L leaves on chemically-induced skin papillomagenesis in mice.

    Science.gov (United States)

    Hamizah, Sulaiman; Roslida, A H; Fezah, O; Tan, K L; Tor, Y S; Tan, C I

    2012-01-01

    Annona muricata L (Annonaceae), commonly known as soursop has a long, rich history in herbal medicine with a lengthy recorded indigenous use. It had also been found to be a promising new anti-tumor agent in numerous in vitro studies. The present investigation concerns chemopreventive effects in a two-stage model of skin papillomagenesis. Chemopreventive effects of an ethanolic extract of A. muricata leaves (AMLE) was evaluated in 6-7 week old ICR mice given a single topical application of 7,12-dimethylbenza(α)anthracene (DMBA 100 μg/100 μl acetone) and promotion by repeated application of croton oil (1% in acetone/ twice a week) for 10 weeks. Morphological tumor incidence, burden and volume were measured, with histological evaluation of skin tissue. Topical application of AMLE at 30, 100 and 300 mg/kg significantly reduced DMBA/croton oil induced mice skin papillomagenesis in (i) peri-initiation protocol (AMLE from 7 days prior to 7 days after DMBA), (ii) promotion protocol (AMLE 30 minutes after croton oil), or (iii) both peri-initiation and promotion protocol (AMLE 7 days prior to 7 day after DMBA and AMLE 30 minutes after croton oil throughout the experimental period), in a dose dependent manner (p<0.05) as compared to carcinogen-treated control. Furthermore, the average latent period was significantly increased in the AMLE-treated group. Interestingly, At 100 and 300 mg/ kg, AMLE completely inhibited the tumor development in all stages. Histopathological study revealed that tumor growth from the AMLE-treated groups showed only slight hyperplasia and absence of keratin pearls and rete ridges. The results, thus suggest that the A.muricata leaves extract was able to suppress tumor initiation as well as tumor promotion even at lower dosage.

  7. Crosstalk between Desmoglein 2 and Patched 1 accelerates chemical-induced skin tumorigenesis

    OpenAIRE

    Brennan-Crispi, DM; Hossain, C; Sahu, J; Brady, M.; Riobo, NA; Mahoney, MG

    2015-01-01

    Aberrant activation of Hedgehog (Hh) signaling is causative of BCCs and has been associated with a fraction of SCCs. Desmoglein 2 (Dsg2) is an adhesion protein that is upregulated in many cancers and overexpression of Dsg2 in the epidermis renders mice more susceptible to squamous-derived neoplasia. Here we examined a potential crosstalk between Dsg2 and Hh signaling in skin tumorigenesis. Our findings show that Dsg2 modulates Gli1 expression, in vitro and in vivo. Ectopic expression of Dsg2 ...

  8. Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth

    International Nuclear Information System (INIS)

    There is a need for rapid, efficient and cost-effective alternatives to traditional in vivo developmental neurotoxicity testing. In vitro cell culture models can recapitulate many of the key cellular processes of nervous system development, including neurite outgrowth, and may be used as screening tools to identify potential developmental neurotoxicants. The present study compared primary rat cortical cultures and human embryonic stem cell-derived neural cultures in terms of: 1) reproducibility of high content image analysis based neurite outgrowth measurements, 2) dynamic range of neurite outgrowth measurements and 3) sensitivity to chemicals which have been shown to inhibit neurite outgrowth. There was a large increase in neurite outgrowth between 2 and 24 h in both rat and human cultures. Image analysis data collected across multiple cultures demonstrated that neurite outgrowth measurements in rat cortical cultures were more reproducible and had higher dynamic range as compared to human neural cultures. Human neural cultures were more sensitive than rat cortical cultures to chemicals previously shown to inhibit neurite outgrowth. Parallel analysis of morphological (neurite count, neurite length) and cytotoxicity (neurons per field) measurements were used to detect selective effects on neurite outgrowth. All chemicals which inhibited neurite outgrowth in rat cortical cultures did so at concentrations which did not concurrently affect the number of neurons per field, indicating selective effects on neurite outgrowth. In contrast, more than half the chemicals which inhibited neurite outgrowth in human neural cultures did so at concentrations which concurrently decreased the number of neurons per field, indicating that effects on neurite outgrowth were secondary to cytotoxicity. Overall, these data demonstrate that the culture models performed differently in terms of reproducibility, dynamic range and sensitivity to neurite outgrowth inhibitors. While human neural

  9. Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth

    Energy Technology Data Exchange (ETDEWEB)

    Harrill, Joshua A.; Freudenrich, Theresa M.; Robinette, Brian L.; Mundy, William R., E-mail: mundy.william@epa.gov

    2011-11-15

    There is a need for rapid, efficient and cost-effective alternatives to traditional in vivo developmental neurotoxicity testing. In vitro cell culture models can recapitulate many of the key cellular processes of nervous system development, including neurite outgrowth, and may be used as screening tools to identify potential developmental neurotoxicants. The present study compared primary rat cortical cultures and human embryonic stem cell-derived neural cultures in terms of: 1) reproducibility of high content image analysis based neurite outgrowth measurements, 2) dynamic range of neurite outgrowth measurements and 3) sensitivity to chemicals which have been shown to inhibit neurite outgrowth. There was a large increase in neurite outgrowth between 2 and 24 h in both rat and human cultures. Image analysis data collected across multiple cultures demonstrated that neurite outgrowth measurements in rat cortical cultures were more reproducible and had higher dynamic range as compared to human neural cultures. Human neural cultures were more sensitive than rat cortical cultures to chemicals previously shown to inhibit neurite outgrowth. Parallel analysis of morphological (neurite count, neurite length) and cytotoxicity (neurons per field) measurements were used to detect selective effects on neurite outgrowth. All chemicals which inhibited neurite outgrowth in rat cortical cultures did so at concentrations which did not concurrently affect the number of neurons per field, indicating selective effects on neurite outgrowth. In contrast, more than half the chemicals which inhibited neurite outgrowth in human neural cultures did so at concentrations which concurrently decreased the number of neurons per field, indicating that effects on neurite outgrowth were secondary to cytotoxicity. Overall, these data demonstrate that the culture models performed differently in terms of reproducibility, dynamic range and sensitivity to neurite outgrowth inhibitors. While human neural

  10. Chemopreventive effects of cardamom (Elettaria cardamomum L.) on chemically induced skin carcinogenesis in Swiss albino mice.

    Science.gov (United States)

    Qiblawi, Samir; Al-Hazimi, Awdah; Al-Mogbel, Mohammed; Hossain, Ashfaque; Bagchi, Debasis

    2012-06-01

    The chemopreventive potential of cardamom was evaluated on 7,12-dimethylbenz[a]anthracene-initiated and croton oil-promoted mouse skin papillomagenesis. A significant reduction in the values of tumor incidence, tumor burden, and tumor yield and the cumulative number of papillomas was observed in mice treated orally with 0.5 mg of cardamom powder in suspension continuously at pre-, peri-, and post-initiational stages of papillomagenesis compared with the control group. The average weight and diameter of tumors recorded were also comparatively lower in the cardamom-treated mouse group. Treatment of cardamom suspension by oral gavage for 15 days resulted in a significant decrease in the lipid peroxidation level of the liver (P < .01). In addition, the reduced glutathione level was significantly elevated in comparison with the control group (P < .05) following cardamom suspension treatment. Taken together, these findings indicate the potential of cardamom as a chemopreventive agent against two-stage skin cancer. PMID:22404574

  11. Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chonglin; Nash, Patrick; Ma, Chunrui; Enriquez, Erik; Wang, Haibing; Xu, Xing; Bao, Shangyong; Collins, Gregory

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo{sub 2}O{sub 5+d} (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  12. Dermatophytosis: fluorostaining enhances speed and sensitivity in direct microscopy of skin, nail and hair specimens from dermatology outpatients.

    Science.gov (United States)

    Ovrén, Ellen; Berglund, Lars; Nordlind, Klas; Rollman, Ola

    2016-07-01

    Direct microscopy of keratinised specimens is a standard screening procedure that assists clinicians to differentiate true superficial mycoses from non-fungal disorders of the skin, nail and hair. Most clinical dermatologists use bright-field microscopy when searching for dermatophyte fungi in clinical samples while laboratory-based mycologists increasingly favour fluorescence microscopy in order to optimise visualisation of fungal elements. This study compared the validity and speediness of fluorescence microscopy vs. conventional light microscopy when screening for fungi in 206 dermatological samples from dermatology outpatients. Both senior dermatologist and a less experienced investigator (medical student) attained high and comparable levels of specificity (91.7-93.8%), positive predictive value (77.1-81.4%) and negative predictive value (83.7-89.9%) using either method. Fluorostaining with Blankophor prior to fluorescence microscopy increased the sensitivity by 22 ± 1% as compared to light microscopy of unstained samples. For both investigators, the time required to identify fungal elements by the fluorescence-based technique was reduced by at least 50%, thus improving the performance of direct microscopy in the clinical setting. PMID:26931645

  13. GA(2)LEN skin test study I: GA(2)LEN harmonization of skin prick testing: novel sensitization patterns for inhalant allergens in Europe

    NARCIS (Netherlands)

    L.M. Heinzerling; G.J. Burbach; G. Edenharter; C. Bachert; C. Bindslev-Jensen; S. Bonini; J. Bousquet; L. Bousquet-Rouanet; P.J. Bousquet; M. Bresciani; A. Bruno; P. Burney; G.W. Canonica; U. Darsow; P. Demoly; S. Durham; W.J. Fokkens; S. Giavi; M. Gjomarkaj; C. Gramiccioni; T. Haahtela; M.L. Kowalski; P. Magyar; G. Muraközi; M. Orosz; N.G. Papadopoulos; C. Röhnelt; G. Stingl; A. Todo-Bom; E. von Mutius; A. Wiesner; S. Wöhrl; T. Zuberbier

    2009-01-01

    BACKGROUND: Skin prick testing is the standard for diagnosing IgE-mediated allergies. However, different allergen extracts and different testing procedures have been applied by European allergy centres. Thus, it has been difficult to compare results from different centres or studies across Europe. I

  14. 皮肤致敏反应体外替代方法的研究现状%Research Situation of in vitro Alternative Methods to Evaluate Skin Sensitization

    Institute of Scientific and Technical Information of China (English)

    洪丽玲; 周庆云

    2012-01-01

    皮肤是人体最大的器官,也是外源化学物入侵机体的第一道天然屏障.化学物作用于皮肤常常导致接触性过敏性皮炎.传统上常常采用豚鼠致敏试验来评价化学物的致敏性.然而,动物试验周期长,结果主观性强,变异程度大,加之如今动物保护主义对动物福利的呼声高涨,替代试验成为必然的发展趋势.本文拟就近年来在皮肤变态反应研究中的替代试验方法进行综述.%The skin is the largest body's organ, and also the first natural barrier to protect the body from the invasion of chemicals. The chemicals often cause the allergic contact dermatitis. Traditionally, the guinea pig sensitization test is often used to evaluate the allergenicity of chemicals. However, as this test has some disadvantages such as too long test cycle, and subjective and variable results, and collides with animal welfare and protection, an alternative test has become the inevitable trend of development. This article reviews the alternative tests in the study on skin allergy in the recent years.

  15. Keratinocyte p38δ loss inhibits Ras-induced tumor formation, while systemic p38δ loss enhances skin inflammation in the early phase of chemical carcinogenesis in mouse skin.

    Science.gov (United States)

    Kiss, Alexi; Koppel, Aaron C; Anders, Joanna; Cataisson, Christophe; Yuspa, Stuart H; Blumenberg, Miroslav; Efimova, Tatiana

    2016-05-01

    p38δ expression and/or activity are increased in human cutaneous malignancies, including invasive squamous cell carcinoma (SCC) and head and neck SCC, but the role of p38δ in cutaneous carcinogenesis has not been well-defined. We have reported that mice with germline loss of p38δ exhibited a reduced susceptibility to skin tumor development compared with wild-type mice in the two-stage 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA) chemical skin carcinogenesis model. Here, we report that p38δ gene ablation inhibited the growth of tumors generated from v-ras(Ha) -transformed keratinocytes in skin orthografts to nude mice, indicating that keratinocyte-intrinsic p38δ is required for Ras-induced tumorigenesis. Gene expression profiling of v-ras(Ha) -transformed p38δ-null keratinocytes revealed transcriptional changes associated with cellular responses linked to tumor suppression, such as reduced proliferation and increased differentiation, cell adhesion, and cell communications. Notably, a short-term DMBA/TPA challenge, modeling the initial stages of chemical skin carcinogenesis treatment, elicited an enhanced inflammation in p38δ-null skin compared with skin of wild-type mice, as assessed by measuring the expression of pro-inflammatory cytokines, including IL-1β, IL-6, IL-17, and TNFα. Additionally, p38δ-null skin and p38δ-null keratinocytes exhibited increased p38α activation and signaling in response to acute inflammatory challenges, suggesting a role for p38α in stimulating the elevated inflammatory response in p38δ-null skin during the initial phases of the DMBA/TPA treatment compared with similarly treated p38δ(+/+) skin. Altogether, our results indicate that p38δ signaling regulates skin carcinogenesis not only by keratinocyte cell-autonomous mechanisms, but also by influencing the interaction between between the epithelial compartment of the developing skin tumor and its stromal microenvironment.

  16. Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Nilofar Asim

    2014-01-01

    Full Text Available The importance of dye sensitized solar cells (DSSCs as a low-cost and environmentally friendly photovoltaic (PV technology has prompted many researchers to improve its efficiency and durability. The realization of these goals is impossible without taking into account the importance of the materials in DSSCs, so the focus on the preparation/deposition methods is essential. These methods can be either chemical or physical. In this study, the chemical applied methods that utilize chemical reaction to synthesize and deposit the materials are covered and categorized according to their gas phase and liquid phase precursors. Film processing techniques that can be used to enhance the materials' properties postpreparation are also included for further evaluation in this study. However, there is a variety of consideration, and certain criteria must be taken into account when selecting a specific deposition method, due to the fact that the fabrication conditions vary and are unoptimized.

  17. The influence of hypoxia on the thermal sensitivity of skin colouration in the bearded dragon, Pogona vitticeps.

    Science.gov (United States)

    de Velasco, Jesus Barraza; Tattersall, Glenn J

    2008-09-01

    One physiological mechanism used by reptiles to remain within thermal optima is their ability to reversibly alter skin colour, imparting changes in overall reflectance, and influencing the rate of heat gain from incident radiation. The ability to lighten or darken their skin is caused by the movement of pigment within the dermal chromatophore cells. Additionally, lizards, as ectotherms, significantly lower their preferred body temperatures when experiencing stressors such as hypoxia. This decrease in preferred temperature has been proposed to be the result of a downward adjustment of the thermal set-point, the temperature around which the body temperature is typically defended. We tested the hypothesis that lightening of the skin in lizards would be modified by hypoxia in a manner consistent with the known reduction in preferred temperatures. Skin colouration values of the dorsal skin of bearded dragons were analysed at three different levels of oxygen (20.8, 9.9 and 4.9 kPa) and at temperatures spanning the preferred temperature range (30, 32, 34, 36, 38 and 40 C). Hypoxic lizards lightened their skin at lower ambient temperatures more than normoxic ones, and in an oxygen-dependent fashion. The orchestrated adjustment of skin reflectance suggests that this physiological trait is being regulated at a new and lower set-point. Evidence from this study demonstrates that skin colouration plays a role in body temperature regulation and that the reduction in temperature set-point so prevalent in hypoxia is also manifested in this physiological trait. PMID:18491114

  18. Chemical characterization of Citrus limon var. pompia and incorporation in phospholipid vesicles for skin delivery.

    Science.gov (United States)

    Manconi, Maria; Manca, Maria Letizia; Marongiu, Francesca; Caddeo, Carla; Castangia, Ines; Petretto, Giacomo Luigi; Pintore, Giorgio; Sarais, Giorgia; D'hallewin, Guy; Zaru, Marco; Bacchetta, Gianluigi; Fadda, Anna Maria

    2016-06-15

    The components of pompia, a hybrid Citrus species cultivated only in Sardinia (Italy), were extracted using an environmentally-friendly method and food-grade solvents. Taking into account that only few data are available on pompia composition, the phytochemical fingerprint of its rind extract was obtained by accurate component separation and identification, combining HPLC and mass spectrometry. Different flavones such as naringin (23.77μg/mg), neoeriocitrin (46.53μg/mg) and neohesperidin (44.57μg/mg) were identified. Additionally, the antioxidant activity and phenolic content were confirmed by DPPH and Folin-Ciocalteu assays. The whole extract was incorporated in innovative phospholipid vesicles, namely glycerosomes, hyalurosomes and glycerol containing hyalurosomes, which were prepared using a high ratio of extract/phospholipid (1/3.5w/w). The in vitro biocompatibility of the nanoincorporated extract and its ability to potentiate the aptitude of the extract to counteract oxidative stress in skin cells were evaluated. The vesicles, especially glycerol containing hyalurosomes, were able to prevent oxidative damage and death of both keratinocytes and fibroblasts, promoting their viability. PMID:27084291

  19. Evolution of metastasis revealed by mutational landscapes of chemically induced skin cancers

    Science.gov (United States)

    McCreery, Melissa Q; Halliwill, Kyle D; Chin, Douglas; Delrosario, Reyno; Hirst, Gillian; Vuong, Peter; Jen, Kuang-Yu; Hewinson, James; Adams, David J; Balmain, Allan

    2016-01-01

    Human tumors show a high level of genetic heterogeneity, but the processes that influence the timing and route of metastatic dissemination of the subclones are unknown. Here we have used whole-exome sequencing of 103 matched benign, malignant and metastatic skin tumors from genetically heterogeneous mice to demonstrate that most metastases disseminate synchronously from the primary tumor, supporting parallel rather than linear evolution as the predominant model of metastasis. Shared mutations between primary carcinomas and their matched metastases have the distinct A-to-T signature of the initiating carcinogen dimethylbenzanthracene, but non-shared mutations are primarily G-to-T, a signature associated with oxidative stress. The existence of carcinomas that either did or did not metastasize in the same host animal suggests that there are tumor-intrinsic factors that influence metastatic seeding. We also demonstrate the importance of germline polymorphisms in determining allele-specific mutations, and we identify somatic genetic alterations that are specifically related to initiation of carcinogenesis by Hras or Kras mutations. Mouse tumors that mimic the genetic heterogeneity of human cancers can aid our understanding of the clonal evolution of metastasis and provide a realistic model for the testing of novel therapies. PMID:26523969

  20. Rapid and sensitive reporter gene assays for detection of antiandrogenic and estrogenic effects of environmental chemicals

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Jørgensen, E.C.B.; Larsen, John Christian

    1999-01-01

    Reports on increasing incidences in developmental abnormalities of the human male reproductive tract and the recent identifications of environmental chemicals with antiandrogenic activity necessitate the screening of a larger number of compounds in order to get an overview of potential antiandrog......Reports on increasing incidences in developmental abnormalities of the human male reproductive tract and the recent identifications of environmental chemicals with antiandrogenic activity necessitate the screening of a larger number of compounds in order to get an overview of potential...... antiandrogenic chemicals present in our environment. Thus, there is a great need for an effective in vitro screening method for (anti)androgenic chemicals. We have developed a rapid, sensitive, and reproducible reporter gene assay for detection of antiandrogenic chemicals. Chinese Hamster Ovary cells were......-on laboratory time. This assay is a powerful tool for the efficient and accurate determination and quantification of the effects of antiandrogens on reporter gene transcription, To extend the application of FuGene, the reagent was shown to be superior compared to Lipofectin for transfecting MCF7 human breast...

  1. Field study of the relationship between skin-sensitizing antibody production in the cottontail rabbit, Sylvilagus floridanus, and infestation by the rabbit tick, Haemaphysalis leporispalustris (Acri: Ixodidae).

    Science.gov (United States)

    McGowan, M J; Camin, J H; McNew, R W

    1979-10-01

    The resistance of cottontail rabbits to tick feeding appears correlated with the rabbits' development of skin-sensitizing antibodies. Resistance appeared to be greatest in adult rabbits which had been repeatedly infested with ticks. Rabbits with little exposure to ticks, usually the young cottontails, showed little or no skin-sensitizing antibody present in their blood and usually had relatively high tick loads when compared with adult rabbits. Models used to interpret the data show promise as tools for predicting tick population fluctuations and, perhaps, incidence of vector borne disease outbreaks. The existence of resistance to tick attachment has important implications for the host-parasite relationship. The research lends support to the hypothesis that the resistance may function as a homeostatic regulatory mechanism capable of maintaining the size of the tick population in equilibrium with the size of the rabbit population. In this way, host resistance may be advantageous to the parasite as well as to the host. PMID:512764

  2. High Sensitivity, Low Power Nano Sensors and Devices for Chemical Sensing

    Science.gov (United States)

    Li, Jing; Powell, Dan; Getty, Stephanie; Lu, Yi-Jiang

    2004-01-01

    The chemical sensor market has been projected to grow to better than $40 billion dollars worldwide within the next 10 years. Some of the primary motivations to develop nanostructured chemical sensors are monitoring and control of environmental pollution; improved diagnostics for consumption; improvement in measurement precision and accuracy; and improved detection limits for Homeland security, battlefield environments, and process and quality control of industrial applications. In each of these applications, there is demand for sensitivity, selectivity and stability of environmental and biohazard detection and capture beyond what is currently commercially available. Nanotechnology offers the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. It is essentially concerned with materials, devices, and systems whose structures and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena, and process control due to their nanoscale size. One such nanotechnology-enabled chemical sensor has been developed at NASA Ames leveraging nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxide nanobelts or nanowires, as a sensing medium bridging a pair of interdigitated electrodes (IDE) realized through a silicon-based microfabrication and micromachining technique. The DE fingers are fabricated on a silicon substrate using standard photolithography and thin film metallization techniques. It is noteworthy that the fabrication techniques employed are not confined to the silicon substrate. Through spin casting and careful substrate selection (i.e. clothing, glass, polymer, etc.), additional degrees of freedom can be exploited to enhance sensitivity or to conform to unique applications. Both in-situ growth of nanostructured materials and casting of nanostructured dispersions were used to produce analogous chemical sensing devices.

  3. A survey of airborne and skin exposures to chemicals in footwear and equipment factories in Thailand.

    Science.gov (United States)

    Todd, Lori A; Mottus, Kathleen; Mihlan, Gary J

    2008-03-01

    This research reports on a pilot industrial hygiene study that was performed at four footwear factories and two equipment factories in Thailand. Workers in these factories were exposed through inhalation and dermal contact to a large number of organic vapors from solvents and cements that were hand applied. In addition, these workers were exposed to highly toxic isocyanates primarily through the dermal route. A total of 286 personal air samples were obtained at the four footwear factories using organic vapor monitors; individual job tasks were monitored using a real-time MIRAN Spectrometer. A total of 64 surface, tool, or hand samples were monitored for isocyanates using surface contamination detectors. Real-time measurements were also obtained for organic vapors in two equipment factories. From 8% to 21% of the workers sampled in each footwear factory were overexposed to mixtures of chemicals from solvents and cements. Up to 100% of the workers performing specific job tasks were overexposed to mixtures of chemicals. From 39% to 69% of the surface samples were positive for unreacted isocyanates. Many of the real-time measurements obtained in the equipment factories exceeded occupational exposure limits. Personal protective equipment and engineering controls were inadequate in all of the factories. PMID:18213531

  4. Influence of drying temperature on the chemical constituents of jaboticaba (Plinia Jaboticaba (Vell.) Berg) skin

    OpenAIRE

    Ana Paula C Alves; Angelita Duarte Corrêa; Flávia Cíntia de Oliveira; Eder Pedroza Isquierdo; Celeste Maria Patto de Abreu; Flávio Meira Borém

    2014-01-01

    Jaboticaba is a fruit native to Brazil. Its skin represents up to 43% of the fruit and contains high levels of fiber, minerals and phenolic compounds. The use of the skin waste adds value to the fruit. However, one of the drawbacks of skin storage is the high water content, which requires drying processes to preserve the skin without leading to the loss of nutrients and antioxidants. The influence of different drying temperatures on the levels of nutrients and antioxidants was investigated. J...

  5. Sensitivity analysis for the comparative assessment of chemical and radiological risks from the waste isolation pilot plan

    International Nuclear Information System (INIS)

    This paper presents the results of sensitivity analyses performed on the models that define a method for the comparative assessment of chemical and radionuclide risks. The comparative risk assessment method was developed to compare the chemical and radionuclide health risks to workers and the general public that may be associated with the disposal of transuranic (TRU) mixed wastes at the Waste Isolation Pilot Plan (WIPP), located near Carlsbad, New Mexico. Sensitivity analyses were performed to identify those model variables that have the greatest impact on the estimation of chemical and radionuclide risks. This paper presents the resulting variables that ranked highest overall in sensitivity on twelve models used in these analyses

  6. Nanoporous framework materials interfaced with mechanical sensors for highly-sensitive chemical sensing.

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-Hwan; Skinner, Jack L.; Houk, Ronald J. T.; Fischer, Roland A.; Robinson, Alex Lockwood; Allendorf, Mark D.; Yusenko, Kirill; Meilikhov, Mikhail; Hesketh, Peter J.; Venkatasubramanian, Anandram; Thornberg, Steven Michael

    2010-04-01

    We will describe how novel nanoporous framework materials (NFM) such as metal-organic frameworks (MOFs) can be interfaced with common mechanical sensors, such as surface acoustic wave (SAW), microcantilever array, and quartz crystal microbalance (QCM) devices, and subsequently be used to provide selectivity and sensitivity to a broad range of analytes including explosives, nerve agents, and volatile organic compounds (VOCs). NFM are highly ordered, crystalline materials with considerable synthetic flexibility resulting from the presence of both organic and inorganic components within their structure. Chemical detection using micro-electro-mechanical-systems (MEMS) devices (i.e. SAWs, microcantilevers) requires the use of recognition layers to impart selectivity. Unlike traditional organic polymers, which are dense, the nanoporosity and ultrahigh surface areas of NFM allow for greater analyte uptake and enhance transport into and out of the sensing layer. This enhancement over traditional coatings leads to improved response times and greater sensitivity, while their ordered structure allows chemical tuning to impart selectivity. We describe here experiments and modeling aimed at creating NFM layers tailored to the detection of water vapor, explosives, CWMD, and volatile organic compound (VOCs), and their integration with the surfaces of MEMS devices. Molecular simulation shows that a high degree of chemical selectivity is feasible. For example, a suite of MOFs can select for strongly interacting organics (explosives, CWMD) vs. lighter volatile organics at trace concentrations. At higher gas pressures, the CWMD are deselected in favor of the volatile organics. We will also demonstrate the integration of various NFM on the surface of microcantiliver arrays, QCM crystals, and SAW devices, and describe new synthetic methods developed to improve the quality of NFM coatings. Finally, MOF-coated MEMS devices show how temperature changes can be tuned to improve response

  7. Ultrafast and sensitive room temperature NH3 gas sensors based on chemically reduced graphene oxide

    Science.gov (United States)

    Hu, Nantao; Yang, Zhi; Wang, Yanyan; Zhang, Liling; Wang, Ying; Huang, Xiaolu; Wei, Hao; Wei, Liangmin; Zhang, Yafei

    2014-01-01

    Ultrafast and sensitive room temperature NH3 gas sensors based on chemically reduced graphene oxide (rGO) are demonstrated in this work. rGO, which was prepared via the reduction of graphene oxide by pyrrole, exhibited excellent responsive sensitivity and selectivity to ammonia (NH3) gas. The high sensing performance of these rGO sensors with resistance change as high as 2.4% and response time as fast as 1.4 s was realized when the concentration of NH3 gas was as low as 1 ppb. Furthermore, the rGO sensors could rapidly recover to their initial states with IR illumination. The devices also showed excellent repeatability and selectivity to NH3. These rGO sensors, with low cost, low power, and easy fabrication, as well as scalable properties, showed great potential for ultrasensitive detection of NH3 gas in a wide variety of fields.

  8. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm-2 mM-1, and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  9. The fetal ovary exhibits temporal sensitivity to a ‘real-life’ mixture of environmental chemicals

    Science.gov (United States)

    Lea, Richard G.; Amezaga, Maria R.; Loup, Benoit; Mandon-Pépin, Béatrice; Stefansdottir, Agnes; Filis, Panagiotis; Kyle, Carol; Zhang, Zulin; Allen, Ceri; Purdie, Laura; Jouneau, Luc; Cotinot, Corinne; Rhind, Stewart M.; Sinclair, Kevin D.; Fowler, Paul A.

    2016-01-01

    The development of fetal ovarian follicles is a critical determinant of adult female reproductive competence. Prolonged exposure to environmental chemicals (ECs) can perturb this process with detrimental consequences for offspring. Here we report on the exposure of pregnant ewes to an environmental mixture of ECs derived from pastures fertilized with sewage sludge (biosolids): a common global agricultural practice. Exposure of pregnant ewes to ECs over 80 day periods during early, mid or late gestation reduced the proportion of healthy early stage fetal follicles comprising the ovarian reserve. Mid and late gestation EC exposures had the most marked effects, disturbing maternal and fetal liver chemical profiles, masculinising fetal anogenital distance and greatly increasing the number of altered fetal ovarian genes and proteins. In conclusion, differential temporal sensitivity of the fetus and its ovaries to EC mixtures has implications for adult ovarian function following adverse exposures during pregnancy. PMID:26931299

  10. The fetal ovary exhibits temporal sensitivity to a 'real-life' mixture of environmental chemicals.

    Science.gov (United States)

    Lea, Richard G; Amezaga, Maria R; Loup, Benoit; Mandon-Pépin, Béatrice; Stefansdottir, Agnes; Filis, Panagiotis; Kyle, Carol; Zhang, Zulin; Allen, Ceri; Purdie, Laura; Jouneau, Luc; Cotinot, Corinne; Rhind, Stewart M; Sinclair, Kevin D; Fowler, Paul A

    2016-01-01

    The development of fetal ovarian follicles is a critical determinant of adult female reproductive competence. Prolonged exposure to environmental chemicals (ECs) can perturb this process with detrimental consequences for offspring. Here we report on the exposure of pregnant ewes to an environmental mixture of ECs derived from pastures fertilized with sewage sludge (biosolids): a common global agricultural practice. Exposure of pregnant ewes to ECs over 80 day periods during early, mid or late gestation reduced the proportion of healthy early stage fetal follicles comprising the ovarian reserve. Mid and late gestation EC exposures had the most marked effects, disturbing maternal and fetal liver chemical profiles, masculinising fetal anogenital distance and greatly increasing the number of altered fetal ovarian genes and proteins. In conclusion, differential temporal sensitivity of the fetus and its ovaries to EC mixtures has implications for adult ovarian function following adverse exposures during pregnancy. PMID:26931299

  11. General practitioners' experiences with provision of healthcare to patients with self-reported multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Skovbjerg, Sine; Johansen, Jeanne Duus; Rasmussen, Alice;

    2009-01-01

    OBJECTIVE: To describe general practitioners' (GPs') evaluation of and management strategies in relation to patients who seek medical advice because of multiple chemical sensitivity (MCS). DESIGN: A nationwide cross-sectional postal questionnaire survey. The survey included a sample of 1000 Danish.......2% of the GPs evaluated the patients' complaints as chronic and 46.2% stated that they were rarely able to meet the patients' expectations for healthcare. The majority, 73.5%, had referred patients to other medical specialties. The cause of MCS was perceived as multi-factorial by 64.3% of the GPs, as somatic...

  12. Experimental assessment of the sensitiveness of an electrochemical oscillator towards chemical perturbations.

    Directory of Open Access Journals (Sweden)

    Graziela C A Ferreira

    Full Text Available In this study we address the problem of the response of a (electrochemical oscillator towards chemical perturbations of different magnitudes. The chemical perturbation was achieved by addition of distinct amounts of trifluoromethanesulfonate (TFMSA, a rather stable and non-specifically adsorbing anion, and the system under investigation was the methanol electro-oxidation reaction under both stationary and oscillatory regimes. Increasing the anion concentration resulted in a decrease in the reaction rates of methanol oxidation and a general decrease in the parameter window where oscillations occurred. Furthermore, the addition of TFMSA was found to decrease the induction period and the total duration of oscillations. The mechanism underlying these observations was derived mathematically and revealed that inhibition in the methanol oxidation through blockage of active sites was found to further accelerate the intrinsic non-stationarity of the unperturbed system. Altogether, the presented results are among the few concerning the experimental assessment of the sensitiveness of an oscillator towards chemical perturbations. The universal nature of the complex chemical oscillator investigated here might be used for reference when studying the dynamics of other less accessible perturbed networks of (biochemical reactions.

  13. Relaxation of the chemical bond skin chemisorption size matter ZTP mechanics H2O myths

    CERN Document Server

    Sun, Chang Q

    2014-01-01

    The aim of this book is to explore the detectable properties of a material to the parameters of bond and non-bond involved and to clarify the interdependence of various properties. This book is composed of four parts; Part I deals with the formation and relaxation dynamics of bond and non-bond during chemisorptions with uncovering of the correlation among the chemical bond, energy band, and surface potential barrier (3B) during reactions; Part II is focused on the relaxation of bonds between atoms with fewer neighbors than the ideal in bulk with unraveling of the bond order-length-strength (BOLS) correlation mechanism, which clarifies the nature difference between nanostructures and bulk of the same substance; Part III deals with the relaxation dynamics of bond under heating and compressing with revealing of rules on the temperature-resolved elastic and plastic properties of low-dimensional materials; Part IV is focused on the asymmetric relaxation dynamics of the hydrogen bond (O:H-O) and the anomalous behav...

  14. Selective and Sensitive Sensing of Flame Retardant Chemicals Through Phage Display Discovered Recognition Peptide.

    Science.gov (United States)

    Jin, Hyo-Eon; Zueger, Chris; Chung, Woo-Jae; Wong, Winnie; Lee, Byung Yang; Lee, Seung-Wuk

    2015-11-11

    We report a highly selective and sensitive biosensor for the detection of an environmentally toxic molecule, decabrominated diphenyl ether (DBDE), one of the most common congeners of the polybrominated frame retardants (polybrominated diphenyl ether (PBDE)), using newly discovered DBDE peptide receptors integrated with carbon nanotube field-effect transistors (CNT-FET). The specific DBDE peptide receptor was identified using a high-throughput screening process of phage library display. The resulting binding peptide carries an interesting consensus binding pocket with two Trp-His/Asn-Trp repeats, which binds to the DBDE in a multivalent manner. We integrated the novel DBDE binding peptide onto the CNT-FET using polydiacetylene coating materials linked through cysteine-maleimide click chemistry. The resulting biosensor could detect the desired DBDE selectively with a 1 fM detection limit. Our combined approaches of selective receptor discovery, material nanocoating through click chemistry, and integration onto a sensitive CNT-FET electronic sensor for desired target chemicals will pave the way toward the rapid development of portable and easy-to-use biosensors for desired chemicals to protect our health and environment. PMID:26455834

  15. Non-specific chemical inhibition of the Fanconi anemia pathway sensitizes cancer cells to cisplatin

    Directory of Open Access Journals (Sweden)

    Jacquemont Céline

    2012-04-01

    Full Text Available Abstract Background Platinum compounds such as cisplatin and carboplatin are DNA crosslinking agents widely used for cancer chemotherapy. However, the effectiveness of platinum compounds is often tempered by the acquisition of cellular drug resistance. Until now, no pharmacological approach has successfully overcome cisplatin resistance in cancer treatment. Since the Fanconi anemia (FA pathway is a DNA damage response pathway required for cellular resistance to DNA interstrand crosslinking agents, identification of small molecules that inhibit the FA pathway may reveal classes of chemicals that sensitize cancer cells to cisplatin. Results Through a cell-based screening assay of over 16,000 chemicals, we identified 26 small molecules that inhibit ionizing radiation and cisplatin-induced FANCD2 foci formation, a marker of FA pathway activity, in multiple human cell lines. Most of these small molecules also compromised ionizing radiation-induced RAD51 foci formation and homologous recombination repair, indicating that they are not selective toward the regulation of FANCD2. These compounds include known inhibitors of the proteasome, cathepsin B, lysosome, CHK1, HSP90, CDK and PKC, and several uncharacterized chemicals including a novel proteasome inhibitor (Chembridge compound 5929407. Isobologram analyses demonstrated that half of the identified molecules sensitized ovarian cancer cells to cisplatin. Among them, 9 demonstrated increased efficiency toward FA pathway-proficient, cisplatin-resistant ovarian cancer cells. Six small molecules, including bortezomib (proteasome inhibitor, CA-074-Me (cathepsin B inhibitor and 17-AAG (HSP90 inhibitor, synergized with cisplatin specifically in FA-proficient ovarian cancer cells (2008 + FANCF, but not in FA-deficient isogenic cells (2008. In addition, geldanamycin (HSP90 inhibitor and two CHK1 inhibitors (UCN-01 and SB218078 exhibited a significantly stronger synergism with cisplatin in FA

  16. Novel chemically cross-linked solid state electrolyte for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yin Xiong; Tan Weiwei; Xiang Wangchun [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)] [Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Lin Yuan, E-mail: Linyuan@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Jingbo, E-mail: jbzhang@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Xiao Xurui; Li Xueping; Zhou Xiaowen; Fang Shibi [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-08-01

    Poly(vinylpyridine-co-ethylene glycol methyl ether methacrylate) (P(VP-co-MEOMA)) and {alpha},{omega}-diiodo poly(ethylene oxide-co-propylene oxide) (I[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub y}I) were synthesized and used as chemically cross-linked precursors of the electrolyte for dye-sensitized solar cells. Meanwhile, {alpha}-iodo poly(ethylene oxide-co-propylene oxide) methyl ether (CH{sub 3}O[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub x}I) was synthesized and added into the electrolyte as an internal plasticizer. Novel polymer electrolyte resulting from chemically cross-linked precursors was obtained by the quaterisation at 90 {sup o}C for 30 min. The characteristics for this kind of electrolyte were investigated by means of ionic conductivity, thermogravimetric and photocurrent-voltage. The ambient ionic conductivity was significantly enhanced to 2.3 x 10{sup -4} S cm{sup -1} after introducing plasticizer, modified-ionic liquid. The weight loss of the solid state electrolyte at 200 {sup o}C was 1.8%, and its decomposition temperature was 287 {sup o}C. Solid state dye-sensitized solar cell based on chemically cross-linked electrolyte presented an overall conversion efficiency of 2.35% under AM1.5 irradiation (100 mW cm{sup -2}). The as-fabricated device maintained 88% of its initial performance at room temperature even without sealing for 30 days, showing a good stability.

  17. Susceptibility of pRb-deficient epidermis to chemical skin carcinogenesis is dependent on the p107 allele dosage.

    Science.gov (United States)

    Santos, Mirentxu; Ruiz, Sergio; Lara, M Fernanda; Segrelles, Carmen; Moral, Marta; Martínez-Cruz, Ana Belén; Ballestín, Claudio; Lorz, Corina; García-Escudero, Ramón; Paramio, Jesús M

    2008-11-01

    Functional inactivation of the pRb-dependent pathway is a general feature of human cancer. However, only a reduced spectrum of tumors displays inactivation of the Rb gene. This can be attributed, at least partially, to the possible overlapping functions carried out by the related retinoblastoma family members p107 and p130. We observed that loss of pRb in epidermis, using the Cre/LoxP technology, results in proliferation and differentiation defects. These alterations are partially compensated by the elevation in the levels of p107. Moreover, epidermis lacking pRb and p107, but not pRb alone, develops spontaneous tumors, and double deficient primary keratinocytes are highly susceptible to Ha-ras-induced transformation. Two-stage chemical carcinogenesis experiments in mice lacking pRb in epidermis revealed a reduced susceptibility in papilloma formation and an increase in the malignant conversion. We have now explored whether the loss of one p107 allele, inducing a decrease in the levels of p107 up to normal levels could restore the susceptibility of pRb-deficient skin to two-stage protocol. We observed partial restoration in the incidence, number, and size of tumors. However, there is no increased malignancy despite sustained p53 activation. We also observed a partial reduction in the levels of proapoptotic proteins in benign papillomas. These data confirm our previous suggestions on the role of p107 as a tumor suppressor in epidermis in the absence of pRb.

  18. Sensitivity enhancement of chemically amplified resists and performance study using EUV interference lithography

    Science.gov (United States)

    Buitrago, Elizabeth; Nagahara, Seiji; Yildirim, Oktay; Nakagawa, Hisashi; Tagawa, Seiichi; Meeuwissen, Marieke; Nagai, Tomoki; Naruoka, Takehiko; Verspaget, Coen; Hoefnagels, Rik; Rispens, Gijsbert; Shiraishi, Gosuke; Terashita, Yuichi; Minekawa, Yukie; Yoshihara, Kosuke; Oshima, Akihiro; Vockenhuber, Michaela; Ekinci, Yasin

    2016-03-01

    Extreme ultraviolet lithography (EUVL, λ = 13.5 nm) is the most promising candidate to manufacture electronic devices for future technology nodes in the semiconductor industry. Nonetheless, EUVL still faces many technological challenges as it moves toward high-volume manufacturing (HVM). A key bottleneck from the tool design and performance point of view has been the development of an efficient, high power EUV light source for high throughput production. Consequently, there has been extensive research on different methodologies to enhance EUV resist sensitivity. Resist performance is measured in terms of its ultimate printing resolution, line width roughness (LWR), sensitivity (S or best energy BE) and exposure latitude (EL). However, there are well-known fundamental trade-off relationships (LRS trade-off) among these parameters for chemically amplified resists (CARs). Here we present early proof-of-principle results for a multi-exposure lithography process that has the potential for high sensitivity enhancement without compromising other important performance characteristics by the use of a Photosensitized Chemically Amplified Resist (PSCAR). With this method, we seek to increase the sensitivity by combining a first EUV pattern exposure with a second UV flood exposure (λ = 365 nm) and the use of a PSCAR. In addition, we have evaluated over 50 different state-of-the-art EUV CARs. Among these, we have identified several promising candidates that simultaneously meet sensitivity, LWR and EL high performance requirements with the aim of resolving line space (L/S) features for the 7 and 5 nm logic node (16 nm and 13 nm half-pitch HP, respectively) for HVM. Several CARs were additionally found to be well resolved down to 12 nm and 11 nm HP with minimal pattern collapse and bridging, a remarkable feat for CARs. Finally, the performance of two negative tone state-of-the-art alternative resist platforms previously investigated was compared to the CAR performance at and

  19. Chemical proteomic map of dimethyl fumarate-sensitive cysteines in primary human T cells.

    Science.gov (United States)

    Blewett, Megan M; Xie, Jiji; Zaro, Balyn W; Backus, Keriann M; Altman, Amnon; Teijaro, John R; Cravatt, Benjamin F

    2016-01-01

    Dimethyl fumarate (DMF) is an electrophilic drug that is used to treat autoimmune conditions, including multiple sclerosis and psoriasis. The mechanism of action of DMF is unclear but may involve the covalent modification of proteins or DMF serving as a prodrug that is converted to monomethyl fumarate (MMF). We found that DMF, but not MMF, blocked the activation of primary human and mouse T cells. Using a quantitative, site-specific chemical proteomic platform, we determined the DMF sensitivity of >2400 cysteine residues in human T cells. Cysteines sensitive to DMF, but not MMF, were identified in several proteins with established biochemical or genetic links to T cell function, including protein kinase Cθ (PKCθ). DMF blocked the association of PKCθ with the costimulatory receptor CD28 by perturbing a CXXC motif in the C2 domain of this kinase. Mutation of these DMF-sensitive cysteines also impaired PKCθ-CD28 interactions and T cell activation, designating the C2 domain of PKCθ as a key functional, electrophile-sensing module important for T cell biology. PMID:27625306

  20. Effect of Skin Sensitizers on Inducible Nitric Oxide Synthase Expression and Nitric Oxide Production in Skin Dendritic Cells: Role of Different Immunosuppressive Drugs

    OpenAIRE

    Cruz, M. T.; Neves, B. M.; Gonçalo, M; Figueiredo, A; C. B. Duarte; Lopes, M C

    2007-01-01

    Nitric oxide (NO) is involved in the pathogenesis of acute and chronic inflammatory conditions, namely in allergic contact dermatitis (ACD). However, the mechanism by which NO acts in ACD remains elusive. The present study focuses on the effects of different contact sensitizers (2,4-dinitrofluorbenzene, 1,4-phenylenediamine, nickel sulfate), the inactive analogue of DNFB, 2,4-dichloronitrobenzene, and two irritants (sodium dodecyl sulphate and benzalkonium chloride) on the expression of the i...

  1. Electroconvulsive therapy substantially reduces symptom severity and social disability associated with multiple chemical sensitivity: a case report

    DEFF Research Database (Denmark)

    Elberling, Jesper; Gulmann, Nils; Rasmussen, Alice

    2010-01-01

    Multiple chemical sensitivity (MCS) is a chronic nonallergic, multisymptom disorder triggered by common environmental chemicals in concentrations considered nontoxic for most individuals. The condition may lead to loss of occupation and social isolation, and no effective treatment has been reported....... Electroconvulsive therapy (ECT) is a safe and effective treatment of severe depression and medical conditions such as chronic pain disorders....

  2. Intra- and inter-laboratory reproducibility and accuracy of the LuSens assay: A reporter gene-cell line to detect keratinocyte activation by skin sensitizers.

    Science.gov (United States)

    Ramirez, Tzutzuy; Stein, Nadine; Aumann, Alexandra; Remus, Tina; Edwards, Amber; Norman, Kimberly G; Ryan, Cindy; Bader, Jackie E; Fehr, Markus; Burleson, Florence; Foertsch, Leslie; Wang, Xiaohong; Gerberick, Frank; Beilstein, Paul; Hoffmann, Sebastian; Mehling, Annette; van Ravenzwaay, Bennard; Landsiedel, Robert

    2016-04-01

    Several non-animal methods are now available to address the key events leading to skin sensitization as defined by the adverse outcome pathway. The KeratinoSens assay addresses the cellular event of keratinocyte activation and is a method accepted under OECD TG 442D. In this study, the results of an inter-laboratory evaluation of the "me-too" LuSens assay, a bioassay that uses a human keratinocyte cell line harboring a reporter gene construct composed of the rat antioxidant response element (ARE) of the NADPH:quinone oxidoreductase 1 gene and the luciferase gene, are described. Earlier in-house validation with 74 substances showed an accuracy of 82% in comparison to human data. When used in a battery of non-animal methods, even higher predictivity is achieved. To meet European validation criteria, a multicenter study was conducted in 5 laboratories. The study was divided into two phases, to assess 1) transferability of the method, and 2) reproducibility and accuracy. Phase I was performed by testing 8 non-coded test substances; the results showed a good transferability to naïve laboratories even without on-site training. Phase II was performed with 20 coded test substances (performance standards recommended by OECD, 2015). In this phase, the intra- and inter-laboratory reproducibility as well as accuracy of the method was evaluated. The data demonstrate a remarkable reproducibility of 100% and an accuracy of over 80% in identifying skin sensitizers, indicating a good concordance with in vivo data. These results demonstrate good transferability, reliability and accuracy of the method thereby achieving the standards necessary for use in a regulatory setting to detect skin sensitizers. PMID:26796489

  3. Following Ostwald ripening in nanoalloys by high-resolution imaging with single-atom chemical sensitivity

    International Nuclear Information System (INIS)

    Several studies have shown that substantial compositional changes can occur during the coarsening of bimetallic nanoparticles (CoPt, AuPd). To explain this phenomenon that could dramatically impacts all the technologically relevant properties of nanoalloys, we have exploited the sensitivity of the latest generation of electron microscope to prove that during the beam-induced coarsening of CoPt nanoparticles, the dynamic of atom exchanges between the particles is different for Co and Pt. By distinguishing the chemical nature of individual atoms of Co and Pt, while they are diffusing on a carbon film, we have clearly shown that Co atoms have a higher mobility than Pt atoms because of their higher evaporation rate from the particles. These atomic-scale observations bring the experimental evidence on the origin of the compositional changes in nanoalloys induced by Ostwald ripening mechanisms.

  4. Following Ostwald ripening in nanoalloys by high-resolution imaging with single-atom chemical sensitivity

    Science.gov (United States)

    Alloyeau, D.; Oikawa, T.; Nelayah, J.; Wang, G.; Ricolleau, C.

    2012-09-01

    Several studies have shown that substantial compositional changes can occur during the coarsening of bimetallic nanoparticles (CoPt, AuPd). To explain this phenomenon that could dramatically impacts all the technologically relevant properties of nanoalloys, we have exploited the sensitivity of the latest generation of electron microscope to prove that during the beam-induced coarsening of CoPt nanoparticles, the dynamic of atom exchanges between the particles is different for Co and Pt. By distinguishing the chemical nature of individual atoms of Co and Pt, while they are diffusing on a carbon film, we have clearly shown that Co atoms have a higher mobility than Pt atoms because of their higher evaporation rate from the particles. These atomic-scale observations bring the experimental evidence on the origin of the compositional changes in nanoalloys induced by Ostwald ripening mechanisms.

  5. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    CERN Document Server

    Pianetta, Piero A; Baur, K; Brennan, S; Homma, T; Kubo, N

    2003-01-01

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO sub 2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conv...

  6. Evaluation of fibrin-based dermal-epidermal organotypic cultures for in vitro skin corrosion and irritation testing of chemicals according to OECD TG 431 and 439.

    Science.gov (United States)

    Morales, Mariana; Pérez, David; Correa, Luis; Restrepo, Luz

    2016-10-01

    Reconstructed human epidermis (RhE) models have been used for in vitro testing of the potential harmful effects of exposure to chemical compounds on health. In the past, skin irritation and corrosion were evaluated in animal models; however, in recent years, due to the bioethics implications of the method and, to minimize the use of experimental animals, alternative procedures have been proposed. The Organisation for Economic Co-operation and Development (OECD) in its test guidelines (TG) 431 and 439 indicates the requirements for validating new methods for the evaluation of skin corrosion and irritation, respectively. Here, we present an in-house human dermal-epidermal model, useful for the performance of these tests. Using the methods described in this work, it was possible to obtain human fibrin-based dermal-epidermal organotypic skin cultures (ORGs) displaying similar histological characteristics to native skin and expressing specific differentiation epithelial proteins. The end points to classify a substance as irritant or corrosive were cell viability evaluated by MTT assay, and cytokine release measured by BD CBA for human inflammatory cytokines. According to the MTT test, the ORGs correctly classified irritating and corrosive substances. Moreover, the cytokine release assay was difficult to interpret in the context of testing chemical hazard classification. Further experiments are needed to validate this new model for the evaluation of surfactants because the fibrin matrix was affected in the presence of these substances.

  7. Abnormal sensitivity of diploid skin fibroblasts from a family with Gardner's syndrome to the lethal effects of X-irradiation, ultraviolet light and mitomycin-C

    International Nuclear Information System (INIS)

    Skin fibroblasts isolated from two members of the same family with the cancer-prone disease Gardner's Syndrome (intestinal polyposis, colon cancer, bone and soft tissue tumors) showed enhanced sensitivity to the lethal effects of X-irradiation, ultraviolet light and mitomycin-C. These cells showed no liquid-holding type recovery following UV-irradiation of confluent cultures, but were normal in their capacity for UV-induced unscheduled DNA synthesis. UV survival was not influenced by post-irradiation incubation with caffeine. (orig.)

  8. Sensitive detection of rutin based on {beta}-cyclodextrin-chemically reduced graphene/Nafion composite film

    Energy Technology Data Exchange (ETDEWEB)

    Liu Kunping; Wei Jinping [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang Chunming, E-mail: wangcm@lzu.edu.cn [School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2011-05-30

    Highlights: > {beta}-CD-graphene composite obtained via a simple sonication-induced assembly. > Accelerating electron transfer on electrode to amplify the electrochemical signal. > A highly sensitive electrochemical sensor for rutin detection. > Good selectivity and reproducibility for the detection of rutin in real samples. - Abstract: An electrochemical sensor based on chemically reduced graphene (CRG) was developed for the sensitive detection of rutin. To construct the base of the sensor, a novel composite was initially fabricated and used as the substrate material by combining CRG and {beta}-cyclodextrin ({beta}-CD) via a simple sonication-induced assembly. Due to the high rutin-loading capacity on the electrode surface and the upstanding electric conductivity of graphene, the electrochemical response of the fabricated sensor was greatly enhanced and displayed excellent analytical performance for rutin detection from 6.0 x 10{sup -9} to 1.0 x 10{sup -5} mol L{sup -1} with a low detection limit of 2.0 x 10{sup -9} mol L{sup -1} at 3{sigma}. Moreover, the proposed electrochemical sensor also exhibited good selectivity and acceptable reproducibility and could be used for the detection of rutin in real samples. Therefore, the present work offers a new way to broaden the analytical applications of graphene in pharmaceutical analysis.

  9. Sensitivity effects in Uk'37 paleotemperature estimation by chemical ionization mass spectrometry.

    Science.gov (United States)

    Chaler, R; Grimalt, J O; Pelejero, C; Calvo, E

    2000-12-15

    Analysis of C37 alkenone mixtures by gas chromatography (GC) with flame ionization detection (FID) and GC coupled to mass spectrometry (GC/MS) in the chemical ionization mode (CI) shows that the later is useful for paleotemperature estimation when ammonia is used as reagent gas. Conversely, the use of isobutane gives rise to Uk'37 readings that are dependent on the amount of C37 alkenones introduced in the system, being unreliable for paleoclimatic studies. However, ammonia CI GC/MS may produce Uk'37 measurements that deviate from those obtained by GC-FID, the method calibrated for temperature estimation from algal cultures and marine sedimentary data. The differences result from changes in relative sensitivity between the di- and triunsaturated alkenones and depend on the instrument used and operational conditions. This problem is solved in the present study by determination of the response factor linear equations for each alkenone and their average relative sensitivity (R) using mixtures of known composition. These parameters allow the transformation of the GC/MS readings into the GC-FID equivalents using the following equation: UG = R x UM/(1 - UM(1 - R)). Examples of the suitability of this approach are given. PMID:11140754

  10. Progress in resolution, sensitivity, and critical dimensional uniformity of EUV chemically amplified resists

    Science.gov (United States)

    Thackeray, James; Cameron, James; Jain, Vipul; LaBeaume, Paul; Coley, Suzanne; Ongayi, Owendi; Wagner, Mike; Rachford, Aaron; Biafore, John

    2013-03-01

    This paper will discuss further progress obtained at Dow for the improvement of the Resolution, Contact critical dimension uniformity(CDU), and Sensitivity of EUV chemically amplified resists. For resolution, we have employed the use of polymer-bound photoacid generator (PBP) concept to reduce the intrinsic acid diffusion that limits the ultimate resolving capability of CA resists. For CDU, we have focused on intrinsic dissolution contrast and have found that the photo-decomposable base (PDB) concept can be successfully employed. With the use of a PDB, we can reduce CDU variation at a lower exposure energy. For sensitivity, we have focused on more efficient EUV photon capture through increased EUV absorption, as well as more highly efficient PAGs for greater acid generating efficiency. The formulation concepts will be confirmed using Prolith stochastic resist modeling. For the 26nm hp contact holes, we get excellent overall process window with over 280nm depth of focus for a 10% exposure latitude Process window. The 1sigma Critical dimension uniformity [CDU] is 1.1 nm. We also obtain 20nm hp contact resolution in one of our new EUV resists.

  11. Influenza viral membrane fusion is sensitive to sterol concentration but surprisingly robust to sterol chemical identity.

    Science.gov (United States)

    Zawada, Katarzyna E; Wrona, Dominik; Rawle, Robert J; Kasson, Peter M

    2016-01-01

    Influenza virions are enriched in cholesterol relative to the plasma membrane from which they bud. Previous work has shown that fusion between influenza virus and synthetic liposomes is sensitive to the amount of cholesterol in either the virus or the target membrane. Here, we test the chemical properties of cholesterol required to promote influenza fusion by replacing cholesterol with other sterols and assaying viral fusion kinetics. We find that influenza fusion with liposomes is surprisingly robust to sterol chemical identity, showing no significant dependence on sterol identity in target membranes for any of the sterols tested. In the viral membrane, lanosterol slowed fusion somewhat, while polar sterols produced a more pronounced slowing and inhibition of fusion. No other sterols tested showed a significant perturbation in fusion rates, including ones previously shown to alter membrane bending moduli or phase behavior. Although fusion rates depend on viral cholesterol, they thus do not require cholesterol's ability to support liquid-liquid phase coexistence. Using electron cryo-microscopy, we further find that sterol-dependent changes to hemagglutinin spatial patterning in the viral membrane do not require liquid-liquid phase coexistence. We therefore speculate that local sterol-hemagglutinin interactions in the viral envelope may control the rate-limiting step of fusion. PMID:27431907

  12. Influenza viral membrane fusion is sensitive to sterol concentration but surprisingly robust to sterol chemical identity

    Science.gov (United States)

    Zawada, Katarzyna E.; Wrona, Dominik; Rawle, Robert J.; Kasson, Peter M.

    2016-01-01

    Influenza virions are enriched in cholesterol relative to the plasma membrane from which they bud. Previous work has shown that fusion between influenza virus and synthetic liposomes is sensitive to the amount of cholesterol in either the virus or the target membrane. Here, we test the chemical properties of cholesterol required to promote influenza fusion by replacing cholesterol with other sterols and assaying viral fusion kinetics. We find that influenza fusion with liposomes is surprisingly robust to sterol chemical identity, showing no significant dependence on sterol identity in target membranes for any of the sterols tested. In the viral membrane, lanosterol slowed fusion somewhat, while polar sterols produced a more pronounced slowing and inhibition of fusion. No other sterols tested showed a significant perturbation in fusion rates, including ones previously shown to alter membrane bending moduli or phase behavior. Although fusion rates depend on viral cholesterol, they thus do not require cholesterol’s ability to support liquid-liquid phase coexistence. Using electron cryo-microscopy, we further find that sterol-dependent changes to hemagglutinin spatial patterning in the viral membrane do not require liquid-liquid phase coexistence. We therefore speculate that local sterol-hemagglutinin interactions in the viral envelope may control the rate-limiting step of fusion. PMID:27431907

  13. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    International Nuclear Information System (INIS)

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conventional techniques have been achieved. This has resulted in minimum detection limits for transition metals of 8 x 107 atoms/cm2. SR-TXRF studies of the amount of metal contamination deposited on a silicon surface as a function of pH and oxygen content of the etching solutions have provided insights into the mechanisms of metal deposition from solutions containing trace amounts of metals ranging from parts per trillion to parts per billion. Furthermore, by using XANES to understand the chemical state of the metal atmos after deposition, it has been possible to develop chemical models for the deposition processes. Examples will be provided for copper deposition from ultra pure water and acidic solutions. (author)

  14. Photooxidation of Tryptophan and Tyrosine Residues in Human Serum Albumin Sensitized by Pterin: A Model for Globular Protein Photodamage in Skin.

    Science.gov (United States)

    Reid, Lara O; Roman, Ernesto A; Thomas, Andrés H; Dántola, M Laura

    2016-08-30

    Human serum albumin (HSA) is the most abundant protein in the circulatory system. Oxidized albumin was identified in the skin of patients suffering from vitiligo, a depigmentation disorder in which the protection against ultraviolet (UV) radiation fails because of the lack of melanin. Oxidized pterins, efficient photosensitizers under UV-A irradiation, accumulate in the skin affected by vitiligo. In this work, we have investigated the ability of pterin (Ptr), the parent compound of oxidized pterins, to induce structural and chemical changes in HSA under UV-A irradiation. Our results showed that Ptr is able to photoinduce oxidation of the protein in at least two amino acid residues: tryptophan (Trp) and tyrosine (Tyr). HSA undergoes oligomerization, yielding protein structures whose molecular weight increases with irradiation time. The protein cross-linking, due to the formation of dimers of Tyr, does not significantly affect the secondary and tertiary structures of HSA. Trp is consumed in the photosensitized process, and N-formylkynurenine was identified as one of its oxidation products. The photosensitization of HSA takes place via a purely dynamic process, which involves the triplet excited state of Ptr. The results presented in this work suggest that protein photodamage mediated by endogenous photosensitizers can significantly contribute to the harmful effects of UV-A radiation on the human skin. PMID:27500308

  15. Chemical applicability domain of the Local Lymph Node Assay (LLNA) for skin sensitisation potency. Part 2. The biological variability of the murine Local Lymph Node Assay (LLNA) for skin sensitisation.

    Science.gov (United States)

    Roberts, David W; Api, Anne Marie; Aptula, Aynur O

    2016-10-01

    The Local Lymph Node Assay (LLNA) is the most common in vivo regulatory toxicology test for skin sensitisation, quantifying potency as the EC3, the concentration of chemical giving a threefold increase in thymidine uptake in the local lymph node. Existing LLNA data can, along with clinical data, provide useful comparator information on the potency of sensitisers. Understanding of the biological variability of data from LLNA studies is important for those developing non-animal based risk assessment approaches for skin allergy. Here an existing set of 94 EC3 values for 12 chemicals, all tested at least three times in the same vehicle have been analysed by calculating standard deviations (SD) for logEC3 values. The SDs range from 0.08 to 0.22. The overall SD for the 94 logEC3 values is 0.147. Thus the 95% confidence limits (2xSD) for LLNA EC3 values are within a factor of 2, comparable to those for physico-chemical measurements such as partition coefficients and solubility. The residual SDs of Quantitative Mechanistic Models (QMMs) based on physical organic chemistry parameters are similar to the overall SD of the LLNA, indicating that QMMs of this type are unlikely to be bettered for predictive accuracy. PMID:27470439

  16. Adverse and beneficial effects of plant extracts on skin and skin disorders.

    Science.gov (United States)

    Mantle, D; Gok, M A; Lennard, T W

    2001-06-01

    Plants are of relevance to dermatology for both their adverse and beneficial effects on skin and skin disorders respectively. Virtually all cultures worldwide have relied historically, or continue to rely on medicinal plants for primary health care. Approximately one-third of all traditional medicines are for treatment of wounds or skin disorders, compared to only 1-3% of modern drugs. The use of such medicinal plant extracts for the treatment of skin disorders arguably has been based largely on historical/anecdotal evidence, since there has been relatively little data available in the scientific literature, particularly with regard to the efficacy of plant extracts in controlled clinical trials. In this article therefore, adverse and beneficial aspects of medicinal plants relating to skin and skin disorders have been reviewed, based on recently available information from the peer-reviewed scientific literature. Beneficial aspects of medicinal plants on skin include: healing of wounds and burn injuries (especially Aloe vera); antifungal, antiviral, antibacterial and acaricidal activity against skin infections such as acne, herpes and scabies (especially tea tree (Melaleuca alternifolia) oil); activity against inflammatory/immune disorders affecting skin (e.g. psoriasis); and anti-tumour promoting activity against skin cancer (identified using chemically-induced two-stage carcinogenesis in mice). Adverse effects of plants on skin reviewed include: irritant contact dermatitis caused mechanically (spines, irritant hairs) or by irritant chemicals in plant sap (especially members of the Ranunculaceae, Euphorbiaceae and Compositae plant families); phytophotodermatitis resulting from skin contamination by plants containing furocoumarins, and subsequent exposure to UV light (notably members of the Umbelliferae and Rutaceae plant families); and immediate (type I) or delayed hypersensitivity contact reactions mediated by the immune system in individuals sensitized to plants

  17. The use of ex vivo human skin tissue for genotoxicity testing

    Energy Technology Data Exchange (ETDEWEB)

    Reus, Astrid A.; Usta, Mustafa [TNO Triskelion BV, Utrechtseweg 48, 3704 HE, Zeist (Netherlands); Krul, Cyrille A.M., E-mail: cyrille.krul@tno.nl [TNO, Utrechtseweg 48, 3704 HE Zeist (Netherlands)

    2012-06-01

    As a result of the chemical legislation concerning the registration, evaluation, authorization and restriction of chemicals (REACH), and the Seventh Amendment to the Cosmetics Directive, which prohibits animal testing in Europe for cosmetics, alternative methods for safety evaluation of chemicals are urgently needed. Current in vitro genotoxicity assays are not sufficiently predictive for the in vivo situation, resulting in an unacceptably high number of misleading positives. For many chemicals and ingredients of personal care products the skin is the first site of contact, but there are no in vitro genotoxicity assays available in the skin for additional evaluation of positive or equivocal responses observed in regulatory in vitro genotoxicity assays. In the present study ex vivo human skin tissue obtained from surgery was used for genotoxicity evaluation of chemicals by using the comet assay. Fresh ex vivo human skin tissue was cultured in an air–liquid interface and topically exposed to 20 chemicals, including true positive, misleading positive and true negative genotoxins. Based on the results obtained in the present study, the sensitivity, specificity and accuracy of the ex vivo skin comet assay to predict in vivo genotoxicity were 89%, 90% and 89%, respectively. Donor and experimental variability were mainly reflected in the magnitude of the response and not the difference between the presence and absence of a genotoxic response. The present study indicates that human skin obtained from surgery is a promising and robust model for safety evaluation of chemicals that are in direct contact with the skin. -- Highlights: ► We use human skin obtained from surgery for genotoxicity evaluation of chemicals. ► We use the comet assay as parameter for genotoxicity in ex vivo human skin. ► Sensitivity, specificity and accuracy to predict in vivo genotoxins are determined. ► Sensitivity, specificity and accuracy are 89%, 90% and 90%, respectively. ► The method

  18. The use of ex vivo human skin tissue for genotoxicity testing

    International Nuclear Information System (INIS)

    As a result of the chemical legislation concerning the registration, evaluation, authorization and restriction of chemicals (REACH), and the Seventh Amendment to the Cosmetics Directive, which prohibits animal testing in Europe for cosmetics, alternative methods for safety evaluation of chemicals are urgently needed. Current in vitro genotoxicity assays are not sufficiently predictive for the in vivo situation, resulting in an unacceptably high number of misleading positives. For many chemicals and ingredients of personal care products the skin is the first site of contact, but there are no in vitro genotoxicity assays available in the skin for additional evaluation of positive or equivocal responses observed in regulatory in vitro genotoxicity assays. In the present study ex vivo human skin tissue obtained from surgery was used for genotoxicity evaluation of chemicals by using the comet assay. Fresh ex vivo human skin tissue was cultured in an air–liquid interface and topically exposed to 20 chemicals, including true positive, misleading positive and true negative genotoxins. Based on the results obtained in the present study, the sensitivity, specificity and accuracy of the ex vivo skin comet assay to predict in vivo genotoxicity were 89%, 90% and 89%, respectively. Donor and experimental variability were mainly reflected in the magnitude of the response and not the difference between the presence and absence of a genotoxic response. The present study indicates that human skin obtained from surgery is a promising and robust model for safety evaluation of chemicals that are in direct contact with the skin. -- Highlights: ► We use human skin obtained from surgery for genotoxicity evaluation of chemicals. ► We use the comet assay as parameter for genotoxicity in ex vivo human skin. ► Sensitivity, specificity and accuracy to predict in vivo genotoxins are determined. ► Sensitivity, specificity and accuracy are 89%, 90% and 90%, respectively. ► The method

  19. A rapid, high sensitivity technique for measuring arsenic in skin phantoms using a portable x-ray tube and detector.

    Science.gov (United States)

    Fleming, David E B; Gherase, Mihai Raul

    2007-10-01

    Using a portable x-ray tube and silicon PiN diode detector, an improved approach to the measurement of arsenic in skin phantoms was demonstrated. Skin phantoms of 8 mm thickness were made from polyester resin, with arsenic concentrations ranging from 0 to 30 microg g(-1). The excitation of characteristic arsenic x-rays was performed with the x-ray tube and K(alpha) x-rays were used as an indicator of arsenic concentration. From repeated phantom measurements, an instrumental minimum detection limit of 0.446 +/- 0.006 microg g(-1) was found, using an acquisition time of 120 s (real time). This compares with previously reported approaches having instrumental minimum detection limits of 3.5 +/- 0.2 microg g(-1) (1800 s real time), 2.3 +/- 0.1 microg g(-1) (1000 s live time) and 0.40 +/- 0.06 microg g(-1) (1000 s live time). PMID:17881796

  20. Chemical management in fungicide sensitivity of Mycosphaerella fijiensis collected from banana fields in México.

    Science.gov (United States)

    Aguilar-Barragan, Alejandra; García-Torres, Ana Elisa; Odriozola-Casas, Olga; Macedo-Raygoza, Gloria; Ogura, Tetsuya; Manzo-Sánchez, Gilberto; James, Andrew C; Islas-Flores, Ignacio; Beltrán-García, Miguel J

    2014-01-01

    The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L(-1) for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for β-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L(-1) for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices.

  1. LSENS: A General Chemical Kinetics and Sensitivity Analysis Code for homogeneous gas-phase reactions. Part 3: Illustrative test problems

    Science.gov (United States)

    Bittker, David A.; Radhakrishnan, Krishnan

    1994-01-01

    LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 3 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 3 explains the kinetics and kinetics-plus-sensitivity analysis problems supplied with LSENS and presents sample results. These problems illustrate the various capabilities of, and reaction models that can be solved by, the code and may provide a convenient starting point for the user to construct the problem data file required to execute LSENS. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions.

  2. Mindfulness-based cognitive therapy for multiple chemical sensitivity: a study protocol for a randomized controlled trial

    OpenAIRE

    Hauge Christian Riise; Bonde Peter Jens E; Rasmussen Alice; Skovbjerg Sine

    2012-01-01

    Abstract Background Multiple chemical sensitivity (MCS) is a condition characterized by recurrent, self-reported symptoms from multiple organ systems, attributable to exposure to a wide range of chemically unrelated substances at low levels. The pathophysiology is unknown, and affected individuals generally favor avoidance of the symptom triggering substances as a coping strategy. The impact of MCS on daily life may thus be severe. An intervention that may effectively reduce the impact of MCS...

  3. Chemical skin defence in the Eastern fire-bellied toad Bombina orientalis: an ultrastructural approach to the mechanism of poison gland rehabilitation after discharge

    Directory of Open Access Journals (Sweden)

    Sara Quagliata

    2008-12-01

    Full Text Available Type I serous glands in the skin of the Eastern yellow-bellied toad Bombina orientalis released their product massively after 10-3 M nor-adrenalin (NA stimulation, mimicking orthosympathetic control on poison emission in chemical skin defence. Features of cutaneous glands involved in this bulk discharge were observed under light and electron microscopes. Furthermore, restoration of depleted glands was followed after 1, 2 and 3 weeks, and compared with serous biosynthesis during larval gland development. Bulk discharge was caused by contraction of myoepithelial cells (mecs encircling the secretory units. Mec compression dramatically affected the secretory unit, but parts of this syncytial cytoplasm were saved from degeneration and cooperated in gland renewal with stem cells from the gland neck. These adenoblasts underwent proliferation and secretory cytodifferentiation, until merging with the syncytium. Cytoplasm that had resumed secretory activity showed the features typical of larval gland development: the endoplasmic reticulum (rer cisterns were aligned in close parallel arrangement and Golgi stacks released minute type I granules. Secretory rehabilitation led to increasing amounts of granule content. In the meantime, rough cisterns decreased in number and assumed the less ordered pattern described in control specimens. Data collected in the present study revealed that chemical skin defence in anurans is a multi-factorial mechanism involving specific activities: mechanical from mecs, biosynthetic from secretory syncytium and proliferative from intercalated stem cells.

  4. Overcoming computational uncertainties to reveal chemical sensitivity in single molecule conduction calculations.

    Science.gov (United States)

    Solomon, Gemma C; Reimers, Jeffrey R; Hush, Noel S

    2005-06-01

    In the calculation of conduction through single molecule's approximations about the geometry and electronic structure of the system are usually made in order to simplify the problem. Previously [G. C. Solomon, J. R. Reimers, and N. S. Hush, J. Chem. Phys. 121, 6615 (2004)], we have shown that, in calculations employing cluster models for the electrodes, proper treatment of the open-shell nature of the clusters is the most important computational feature required to make the results sensitive to variations in the structural and chemical features of the system. Here, we expand this and establish a general hierarchy of requirements involving treatment of geometrical approximations. These approximations are categorized into two classes: those associated with finite-dimensional methods for representing the semi-infinite electrodes, and those associated with the chemisorption topology. We show that ca. 100 unique atoms are required in order to properly characterize each electrode: using fewer atoms leads to nonsystematic variations in conductivity that can overwhelm the subtler changes. The choice of binding site is shown to be the next most important feature, while some effects that are difficult to control experimentally concerning the orientations at each binding site are actually shown to be insignificant. Verification of this result provides a general test for the precision of computational procedures for molecular conductivity. Predictions concerning the dependence of conduction on substituent and other effects on the central molecule are found to be meaningful only when they exceed the uncertainties of the effects associated with binding-site variation.

  5. Chemical reactivity trends of ergotamine and butenolide from electrostatic potentials and charge sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Mrozek, J.; Michalak, A. [Jagiellonian Univ., Cracow (Poland)

    1995-12-05

    A set of reactivity indices, including maps of the electrostatic potential and local and condensed Fukui function (FF) indices in the atomic resolution, are reported for two vasoconstricting mycotoxins: butenolide and ergotamine; both the finite difference approach of Parr and Yan as well as charge sensitivity analysis, determining the charge responses via the inversion of the hardness tensor, have been used to generate the FF data. These two routes of arriving at the atomic FF indices provide an opportunity to evaluate the available parametrizations of the semiempirical NDDO-type of methods which have been used to determine the input charge distribution; namely, the best parametrization should generate consistent FF predictions resulting from both approaches. For butenolide, the MNDO parametrization was found to fulfill this consistency requirement. The chemical reactivity information has been used to trace possible similarities in reactivity trends of the butenolide molecule and the related fragment of ergotamine, toward hypothetical nucleophilic, electrophilic, and radical attacks. These predictions have been compared to experimental data available for other unsaturated lactones. 13 refs., 18 figs., 1 tab.

  6. [Infection of skin fibroblasts in animals with different levels of sensitivity to Leishmania infantum and Leishmania mexicana (Kinetoplastida: Trypanosomatidae)].

    Science.gov (United States)

    Minero, Miguel Angel; Chinchilla, Misael; Guerrero, Olga Marta; Castro, Alfredo

    2004-03-01

    Infection and multiplication of Leishmania infantum and L. mexicana inside of skin fibroblasts from hamsters, mice and rats was achieved. This process was demonstrated either by counting parasites inside the stained cells or by electronic microscopy studies. In addition multiplication rate differences in the cells from these rodent species were determined, for L. infantum as well as for L. mexicana. Parasite development in hamsters and mice fibroblasts was evident but there was not multiplication in rat cells showing that apparently they are refractory to Leishmania infection. These results suggest that the parasite affinity for each animal, as well as any intracellular environment resistance, could involve genetic factors in the parasite multiplication. On the other hand, presence of amastigote multiplication inside of parasitophorus vacuole, showed by electronic microscopy images, probes a true parasite transformation. Therefore it is suggested that fibroblasts could work as host cells for parasite survival and permanency in the infected animals. PMID:17357424

  7. PH Sensitive Polymers for Improving Reservoir Sweep and Conformance Control in Chemical Flooring

    Energy Technology Data Exchange (ETDEWEB)

    Mukul Sharma; Steven Bryant; Chun Huh

    2008-03-31

    There is an increasing opportunity to recover bypassed oil from depleted, mature oilfields in the US. The recovery factor in many reservoirs is low due to inefficient displacement of the oil by injected fluids (typically water). The use of chemical flooding methods to increase recovery efficiencies is severely constrained by the inability of the injected chemicals to contact the bypassed oil. Low sweep efficiencies are the primary cause of low oil recoveries observed in the field in chemical flooding operations even when lab studies indicate high oil recovery efficiency. Any technology that increases the ability of chemical flooding agents to better contact the remaining oil and reduce the amount of water produced in conjunction with the produced oil will have a significant impact on the cost of producing oil domestically in the US. This translates directly into additional economically recoverable reserves, which extends the economic lives of marginal and mature wells. The objective of this research project was to develop a low-cost, pH-triggered polymer for use in IOR processes to improve reservoir sweep efficiency and reservoir conformance in chemical flooding. Rheological measurements made on the polymer solution, clearly show that it has a low viscosity at low pH and exhibits a sudden increase in viscosity (by 2 orders of magnitude or more) at a pH of 3.5 to 4. This implies that the polymer would preferentially flow into zones containing water since the effective permeability to water is highest in these zones. As the pH of the zone increases due to the buffering capacity of the reservoir rock, the polymer solution undergoes a liquid to gel transition causing a sharp increase in the viscosity of the polymer solution in these zones. This allows operationally robust, in-depth conformance treatment of such water bearing zones and better mobility control. The rheological properties of HPAM solutions were measured. These include: steady-shear viscosity and

  8. High incidence of ultraviolet-B- or chemical-carcinogen-induced skin tumours in mice lacking the xeroderma pigmentosum group A gene

    International Nuclear Information System (INIS)

    Xeroderma pigmentosum (XP) is an autosomal recessive disorder characterized by a high frequency of skin cancer on sun-exposed areas, and neurological complications. XP has a defect in the early step(s) of nucleotide-excision repair (NER) and consists of eight different genetic complementation groups (groups A-G and a variant)1. We established XPA (group-A XP) gene-deficient mice by gene targeting of mouse embryonic stem (ES) cells. The XPA-deficient mice showed neither obvious physical abnormalities more pathological alterations, but were defective in NER and highly susceptible to ultraviolet-B- or 9,10-dimethyl-1,2-benz[a]anthracene-induced skin carcinogenesis. These findings provide in vivo evidence that the XPA protein protects mice from carcinogenesis initiated by ultraviolet or chemical carcinogen. The XPA-deficient mice may provide a good in vivo model to study the high incidence of carcinogenesis in group A XP patients. (Author)

  9. [Studies on chemical protectors against radiation. XXXI. Protection effects of Aloe arborescens on skin injury induced by X-irradiation].

    Science.gov (United States)

    Sato, Y; Ohta, S; Shinoda, M

    1990-11-01

    Protective effects of Aloe arborescens (AA) on mouse skin injury induced by soft X-irradiation were examined. The mechanisms on radiation protection by measuring scavenge activity of activated oxygen, protective effects of nucleic acid, induction of antioxidative protein and so on were further investigated. Consequently a significant protective effect of skin injury was observed in AA S6-3-b. As the mechanisms of radiation protection in AA, the following matters were found. AA S6-3-b showed scavenge activity of hydroxyl radicals generated by Haber-Weiss reaction. AA S6-3-b suppressed the changes of activity in superoxide dismutase and glutathione peroxidase at 7d after soft X-irradiation. Metallothionein was induced in the skin and liver against normal mice at 24 h after administration of AA S6-3-b. PMID:2082014

  10. Studies on chemical protectors against radiation, 31; Protection effects of Aloe arborescens on skin injury induced by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yushi; Ohta, Setsuko; Shinoda, Masato (Hoshi Univ., Tokyo (Japan))

    1990-11-01

    Protective effects of Aloe arborescens (AA) on mouse skin injury induced by soft X-irradiation were examined. The mechanisms on radiation protection by measuring scavenge activity of activated oxygen, protective effects of nucleic acid, induction of antioxidative protein and so on were further investigated. Consequently a significant protective effect of skin injury was observed in AA S6-3-b. As the mechanisms of radiation protection in AA, the following matters were found. AA S6-3-b showed scavenge activity of hydroxyl radicals generated by Haber-Weiss reaction. AA S6-3-b suppressed the changes of activity in superoxide dismutase and gluthathione peroxidase at 7d after soft X-irradiation. Metallothionein was induced in the skin and liver against normal mice at 24 h after administration of AA S6-3-b. (author).

  11. [Studies on chemical protectors against radiation. XXXIII. Protective mechanisms of various compounds against skin injury induced by radiation].

    Science.gov (United States)

    Sato, Y; Kumazawa, N; Suzuki, M; Wang, C M; Ohta, S; Shinoda, M

    1991-01-01

    The radiation protective mechanisms on skin injury induced by soft X-irradiation were investigated by use of various radiation protective agents such as sulfur compounds (MEA, MEG, thiourea), nucleic acid constitutional compounds (adenosine, inosine), antioxidative compounds (sesamol, ferulic acid, ascorbic acid), crude drugs (Rosae Fructus, Anemarrhenae Rhizoma, Trapae Fructus, Forsythiae Fructus, Aloe arborescens). Scavenge action of activated oxygen, inhibitory effect of lipid peroxidation, induction of antioxidative protein and protective effect against damage of deoxyribonucleic acid and superoxide dismutase by X-irradiation were evaluated as the radiation protective mechanisms, and relationship between these results and protective effect of skin injury induced by radiation was studied. PMID:1905349

  12. Studies on chemical protectors against radiation, 33; Protective mechanisms of various compounds against skin injury induced by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yushi; Kumazawa, Noriko; Suzuki, Makoto; Wang Cheng-Ming; Ohta, Setsuko; Shinoda, Masato (Hoshi Univ., Tokyo (Japan))

    1991-01-01

    The radiation protective mechanisms on skin injury induced by soft X-irradiation were investigated by use of various radiation protective agents such as sulfur compounds (MEA, MEG, thiourea), nucleic acid constitutional compounds (adenosine, inosine), antioxidative compounds (sesamol, ferulic acid, ascorbic acid), crude drugs (Rosae Fructus, Anemarrhenae Rhizoma, Trapae Fructus, Forsythiae Fructus, Aloe arborescens). Scavenge action of activated oxygen, inhibitory effect of lipid peroxidation, induction of antioxidative protein and protective effect against damage of deoxyribonucleic acid and superoxide dismutase by X-irradiation were evaluated as the radiation protective mechanisms, and relationship between these results and protective effect of skin injury induced by radiation was studied. (author).

  13. Xenobiotic metabolism capacities of human skin in comparison with a 3D-epidermis model and keratinocyte-based cell culture as in vitro alternatives for chemical testing: phase II enzymes.

    Science.gov (United States)

    Götz, Christine; Pfeiffer, Roland; Tigges, Julia; Ruwiedel, Karsten; Hübenthal, Ulrike; Merk, Hans F; Krutmann, Jean; Edwards, Robert J; Abel, Josef; Pease, Camilla; Goebel, Carsten; Hewitt, Nicola; Fritsche, Ellen

    2012-05-01

    The 7th Amendment to the EU Cosmetics Directive prohibits the use of animals in cosmetic testing for certain endpoints, such as genotoxicity. Therefore, skin in vitro models have to replace chemical testing in vivo. However, the metabolic competence neither of human skin nor of alternative in vitro models has so far been fully characterized, although skin is the first-pass organ for accidentally or purposely (cosmetics and pharmaceuticals) applied chemicals. Thus, there is an urgent need to understand the xenobiotic-metabolizing capacities of human skin and to compare these activities to models developed to replace animal testing. We have measured the activity of the phase II enzymes glutathione S-transferase, UDP-glucuronosyltransferase and N-acetyltransferase in ex vivo human skin, the 3D epidermal model EpiDerm 200 (EPI-200), immortalized keratinocyte-based cell lines (HaCaT and NCTC 2544) and primary normal human epidermal keratinocytes. We show that all three phase II enzymes are present and highly active in skin as compared to phase I. Human skin, therefore, represents a more detoxifying than activating organ. This work systematically compares the activities of three important phase II enzymes in four different in vitro models directly to human skin. We conclude from our studies that 3D epidermal models, like the EPI-200 employed here, are superior over monolayer cultures in mimicking human skin xenobiotic metabolism and thus better suited for dermatotoxicity testing. PMID:22509834

  14. Lack of contralateral suppression in transient-evoked otoacoustic emissions in multiple chemical sensitivity: a clinical correlation study.

    Science.gov (United States)

    Micarelli, Alessandro; Viziano, Andrea; Genovesi, Giuseppe; Bruno, Ernesto; Ottaviani, Fabrizio; Alessandrini, Marco

    2016-01-01

    Multiple chemical sensitivity (MCS) is a chronic disorder characterized by a variety of symptoms associated with the exposure to chemicals at a concentration below the toxic level. Previous studies have demonstrated peculiar responses in brain activity in these patients with respect to sensory stimuli while the association between chemical sensitivity and other environmental intolerances such as noise sensitivity has been questioned by researchers. In this study, a cohort of 18 MCS patients underwent transient-evoked otoacoustic emission (TEOAE) testing with and without contralateral suppression to evaluate the functionality of the medial olivocochlear (MOC) reflex involved in speech-in-noise sensitivity. Results were compared with an age- and gender-matched control group (n = 20) and correlation analysis with disease onset and quick environmental exposure sensitivity inventory (qEESI) symptom severity scale was performed. Subjects affected by MCS showed statistically significant impairment of MOC reflex, and the onset of the disease and several symptom subscales showed to be correlated to such reduction in some of the frequencies tested. These data suggest that alterations of MOC reflex could be part of the complex features of this disease although more studies are needed to further explore auditory perception disorders in environmental intolerances. PMID:27157687

  15. Lack of contralateral suppression in transient-evoked otoacoustic emissions in multiple chemical sensitivity: a clinical correlation study

    Directory of Open Access Journals (Sweden)

    Alessandro Micarelli

    2016-01-01

    Full Text Available Multiple chemical sensitivity (MCS is a chronic disorder characterized by a variety of symptoms associated with the exposure to chemicals at a concentration below the toxic level. Previous studies have demonstrated peculiar responses in brain activity in these patients with respect to sensory stimuli while the association between chemical sensitivity and other environmental intolerances such as noise sensitivity has been questioned by researchers. In this study, a cohort of 18 MCS patients underwent transient-evoked otoacoustic emission (TEOAE testing with and without contralateral suppression to evaluate the functionality of the medial olivocochlear (MOC reflex involved in speech-in-noise sensitivity. Results were compared with an age- and gender-matched control group (n = 20 and correlation analysis with disease onset and quick environmental exposure sensitivity inventory (qEESI symptom severity scale was performed. Subjects affected by MCS showed statistically significant impairment of MOC reflex, and the onset of the disease and several symptom subscales showed to be correlated to such reduction in some of the frequencies tested. These data suggest that alterations of MOC reflex could be part of the complex features of this disease although more studies are needed to further explore auditory perception disorders in environmental intolerances.

  16. Estimation of mean-glandular dose from monitoring breast entrance skin air kerma using a high sensitivity metal oxide semiconductor field effect transistor (MOSFET) dosimeter system in mammography.

    Science.gov (United States)

    Dong, S L; Chu, T C; Lee, J S; Lan, G Y; Wu, T H; Yeh, Y H; Hwang, J J

    2002-12-01

    Estimation of mean-glandular dose (MGD) has been investigated in recent years due to the potential risks of radiation-induced carcinogenesis associated with the mammographic examination for diagnostic radiology. In this study, a new technique for immediate readout of breast entrance skin air kerma (BESAK) using high sensitivity MOSFET dosimeter after mammographic projection was introduced and a formula for the prediction of tube output with exposure records was developed. A series of appropriate conversion factors was applied to the MGD determination from the BESAK. The study results showed that signal response of the high sensitivity MOSFET exhibited excellent linearity within mammographic dose ranges, and that the energy dependence was less than 3% for each anode/filter combination at the tube potentials 25-30 kV. Good agreement was observed between the BESAK and the tube exposure output measurement for breasts thicker than 30 mm. In addition, the air kerma estimated from our prediction formula provided sufficient accuracy for thinner breasts. The average MGD from 120 Asian females was 1.5 mGy, comparable to other studies. Our results suggest that the high sensitivity MOSFET dosimeter system is a good candidate for immediately readout of BESAK after mammographic procedures.

  17. International ring trial of the epidermal equivalent sensitizer potency assay: reproducibility and predictive capacity

    NARCIS (Netherlands)

    M.A.T. Teunis; S.W. Spiekstra; M. Smits; E. Adriaens; T. Eltze; V. Galbiati; C. Krul; R. Landsiedel; R. Pieters; J. Reinders; E. Roggen; E. Corsini; S. Gibbs

    2014-01-01

    This study describes the international ring trial of the epidermal-equivalent (EE) sensitizer potency assay. This assay does not distinguish a sensitizer from a non-sensitizer, but may classify known skin sensitizers according to their potency. It assesses the chemical concentration resulting in 50%

  18. Involvement of Subcortical Brain Structures During Olfactory Stimulation in Multiple Chemical Sensitivity.

    Science.gov (United States)

    Alessandrini, Marco; Micarelli, Alessandro; Chiaravalloti, Agostino; Bruno, Ernesto; Danieli, Roberta; Pierantozzi, Mariangela; Genovesi, Giuseppe; Öberg, Johanna; Pagani, Marco; Schillaci, Orazio

    2016-03-01

    Multiple chemical sensitivity (MCS) patients usually react to odour compounds and the majority of neuroimaging studies assessed, especially at the cortical level, many olfactory-related correlates. The purpose of the present study was to depict sub-cortical metabolic changes during a neutral (NC) and pure (OC) olfactory stimulation by using a recently validated (18)F-2-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography/computer tomography procedure in 26 MCS and 11 healthy (HC) resting subjects undergoing a battery of clinical tests. Twelve subcortical volumes of interest were identified by the automated anatomical labeling library and normalized to thalamus FDG uptake. In both groups, when comparing OC to NC, the within-subjects ANOVA demonstrated a relative decreased metabolism in bilateral putamen and hippocampus and a relative increased metabolism in bilateral amygdala, olfactory cortex (OLF), caudate and pallidum. The between-groups ANOVA demonstrated in MCS a significant higher metabolism in bilateral OLF during NC. As in HC subjects negative correlations were found in OC between FDG uptake in bilateral amygdala and hippocampus and odor pleasantness scale, the latter positively correlated with MCS subjects' bilateral putamen FDG uptake in OC. Besides FDG uptake resemblances in both groups were found, for the first time a relative higher metabolism increase in OLF in MCS subjects at rest with respect to HC was found. When merging this aspect to the different subcortical FDG uptake correlations patterns in the two groups, the present study demonstrated to describe a peculiar metabolic index of behavioral and neurological aspects of MCS complaints. PMID:26438099

  19. Sensitivity of polar stratospheric ozone loss to uncertainties in chemical reaction kinetics

    Directory of Open Access Journals (Sweden)

    S. R. Kawa

    2009-06-01

    Full Text Available The impact and significance of uncertainties in model calculations of stratospheric ozone loss resulting from known uncertainty in chemical kinetics parameters is evaluated in trajectory chemistry simulations for the Antarctic and Arctic polar vortices. The uncertainty in modeled ozone loss is derived from Monte Carlo scenario simulations varying the kinetic (reaction and photolysis rate parameters within their estimated uncertainty bounds. Simulations of a typical winter/spring Antarctic vortex scenario and Match scenarios in the Arctic produce large uncertainty in ozone loss rates and integrated seasonal loss. The simulations clearly indicate that the dominant source of model uncertainty in polar ozone loss is uncertainty in the Cl2O2 photolysis reaction, which arises from uncertainty in laboratory-measured molecular cross sections at atmospherically important wavelengths. This estimated uncertainty in JCl2O2 from laboratory measurements seriously hinders our ability to model polar ozone loss within useful quantitative error limits. Atmospheric observations, however, suggest that the Cl2O2 photolysis uncertainty may be less than that derived from the lab data. Comparisons to Match, South Pole ozonesonde, and Aura Microwave Limb Sounder (MLS data all show that the nominal recommended rate simulations agree with data within uncertainties when the Cl2O2 photolysis error is reduced by a factor of two, in line with previous in situ ClOx measurements. Comparisons to simulations using recent cross sections from Pope et al. (2007 are outside the constrained error bounds in each case. Other reactions producing significant sensitivity in polar ozone loss include BrO+ClO and its branching ratios. These uncertainties challenge our confidence in modeling polar ozone depletion and projecting future changes in response to changing halogen

  20. Sensitivity of chemical vapor deposition diamonds to DD and DT neutrons at OMEGA and the National Ignition Facility

    Science.gov (United States)

    Kabadi, N. V.; Sio, H.; Glebov, V.; Gatu Johnson, M.; MacPhee, A.; Frenje, J. A.; Li, C. K.; Seguin, F.; Petrasso, R.; Forrest, C.; Knauer, J.; Rinderknecht, H. G.

    2016-11-01

    The particle-time-of-flight (pTOF) detector at the National Ignition Facility (NIF) is used routinely to measure nuclear bang-times in inertial confinement fusion implosions. The active detector medium in pTOF is a chemical vapor deposition diamond. Calibration of the detectors sensitivity to neutrons and protons would allow measurement of nuclear bang times and hot spot areal density (ρR) on a single diagnostic. This study utilizes data collected at both NIF and Omega in an attempt to determine pTOF's absolute sensitivity to neutrons. At Omega pTOF's sensitivity to DT-n is found to be stable to within 8% at different bias voltages. At the NIF pTOF's sensitivity to DD-n varies by up to 59%. This variability must be decreased substantially for pTOF to function as a neutron yield detector at the NIF. Some possible causes of this variability are ruled out.

  1. Host-cell reactivation of UV-irradiated and chemically-treated herpes simplex virus-1 by xeroderma pigmentosum, xp heterozygotes and normal skin fibroblasts

    International Nuclear Information System (INIS)

    The host-cell reactivation of UV-irradiated and N-acetoxy-2-acetylamino-fluorene-treated herpes simplex virus type 1 strain MP was studied in normal and xeroderma pigmentosum human skin fibroblasts. Virus treated with either agent demonstrated lower survival in XP cells from complementation groups A, B, C and D than in normal fibroblasts. The relative reactivation ability of XP cells from the different genetic complementation groups was found to be the same for both irradiated and chemically treated virus. In addition, the inactivation kinetics for virus treated with either agent in the XP variant were comparable to that seen in normal skin fibroblasts. The addition of 2 or 4 mmoles caffeine to the post-infection assay medium had no effect on the inactivation kinetics of virus treated by either agent in the XP variant or in XP cells from the different genetic complementation groups. Treatment of the virus with nitrogen mustard resulted in equivalent survival in normal and XP genetic complementation group D cells. No apparent defect was observed in the ability of XP heterozygous skin fibroblasts to repair virus damaged with up to 100 μg N-acetoxy-2-acetylaminofluorene per ml. These findings indicate that the repair of UV-irradiated and N-acetoxy-2-acetylaminofluorene-treated virus is accomplished by the same pathway or different pathways sharing a common intermediate step and that the excision defect of XP cells plays little if any role in the reactivation of nitrogen mustard treated virus. (Auth.)

  2. Evidence of heterosynaptic LTD in the human nociceptive system: superficial skin neuromodulation using a matrix electrode reduces deep pain sensitivity.

    Directory of Open Access Journals (Sweden)

    Martin Mücke

    Full Text Available Long term depression (LTD is a neuronal learning mechanism after low frequency stimulation (LFS. This study compares two types of electrodes (concentric vs. matrix and stimulation frequencies (4 and 30 Hz to examine homo- and heterosynaptic effects indirectly depicted from the somatosensory profile of healthy subjects. Both electrodes were compared in a prospective, randomized, controlled cross-over study using 4 Hz as the conditioning LFS compared to 30 Hz (intended sham condition. Quantitative sensory testing (QST was used to examine 13 thermal and mechanical detection and pain thresholds. Sixteen healthy volunteers (10 women, age 31.0 ± 12.7 years were examined. Depending on the electrodes and frequencies used a divergent pattern of sensory minus signs occurred. Using LFS the concentric electrode increased thermal thresholds, while the matrix electrode rather increased mechanical including deep pain thresholds. Findings after cutaneous neuromodulation using LFS and a matrix electrode are consistent with the concept of heterosynaptic LTD in the human nociceptive system, where deep pain sensitivity was reduced after superficial stimulation of intraepidermal nerve fibres. Cutaneous neuromodulation using LFS and a matrix electrode may be a useful tool to influence deep pain sensitivity in a variety of chronic pain syndromes.

  3. Sensitivity of chemical transport model simulations to the duration of chemical and transport operators: a case study with GEOS-Chem v10-01

    Science.gov (United States)

    Philip, S.; Martin, R. V.; Keller, C. A.

    2015-11-01

    Chemical transport models involve considerable computational expense. Fine temporal resolution offers accuracy at the expense of computation time. Assessment is needed of the sensitivity of simulation accuracy to the duration of chemical and transport operators. We conduct a series of simulations with the GEOS-Chem chemical transport model at different temporal and spatial resolutions to examine the sensitivity of simulated atmospheric composition to temporal resolution. Subsequently, we compare the tracers simulated with operator durations from 10 to 60 min as typically used by global chemical transport models, and identify the timesteps that optimize both computational expense and simulation accuracy. We found that longer transport timesteps increase concentrations of emitted species such as nitrogen oxides and carbon monoxide since a more homogeneous distribution reduces loss through chemical reactions and dry deposition. The increased concentrations of ozone precursors increase ozone production at longer transport timesteps. Longer chemical timesteps decrease sulfate and ammonium but increase nitrate due to feedbacks with in-cloud sulfur dioxide oxidation and aerosol thermodynamics. The simulation duration decreases by an order of magnitude from fine (5 min) to coarse (60 min) temporal resolution. We assess the change in simulation accuracy with resolution by comparing the root mean square difference in ground-level concentrations of nitrogen oxides, ozone, carbon monoxide and secondary inorganic aerosols with a finer temporal or spatial resolution taken as truth. Simulation error for these species increases by more than a factor of 5 from the shortest (5 min) to longest (60 min) temporal resolution. Chemical timesteps twice that of the transport timestep offer more simulation accuracy per unit computation. However, simulation error from coarser spatial resolution generally exceeds that from longer timesteps; e.g. degrading from 2° × 2.5° to 4° × 5

  4. A framework incorporating the impact of exposure scenarios and application conditions on risk assessment of chemicals applied to skin

    OpenAIRE

    Dancik, Yuri; Troutman, John A; Jaworska, Joanna

    2013-01-01

    Purpose 1. To develop a framework for exposure calculation via the dermal route to meet the needs of 21st century toxicity testing and refine current approaches; 2. To demonstrate the impact of exposure scenario and application conditions on the plasma concentration following dermal exposure. Method A workflow connecting a dynamic skin penetration model with a generic whole-body physiologically-based pharmacokinetic (PBPK) model was developed. The impact of modifying exposure scenarios and ap...

  5. Experimental Assessment of the Sensitiveness of an Electrochemical Oscillator towards Chemical Perturbations

    OpenAIRE

    Ferreira, Graziela C. A.; Batista, Bruno C.; Hamilton Varela

    2012-01-01

    In this study we address the problem of the response of a (electro)chemical oscillator towards chemical perturbations of different magnitudes. The chemical perturbation was achieved by addition of distinct amounts of trifluoromethanesulfonate (TFMSA), a rather stable and non-specifically adsorbing anion, and the system under investigation was the methanol electro-oxidation reaction under both stationary and oscillatory regimes. Increasing the anion concentration resulted in a decrease in the ...

  6. Skin tribology: Science friction?

    OpenAIRE

    Heide, van der, M.; X. Zeng; Masen, M.A.

    2013-01-01

    The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is frequently one of the interacting surfaces in relative motion. People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch....

  7. Brown bullhead (Ameiurus nebulosus) skin carcinogenesis.

    Science.gov (United States)

    Bunton, T E

    2000-06-01

    Alternative models using fish species have been tested in liver toxicity and carcinogenesis bioassays. Similar models have not been developed for skin. The brown bullhead (Ameiurus nebulosus) has shown potential as a model for skin carcinogenesis studies due to its sensitivity to environmental chemical pollutants. The present study is an initial morphologic and biochemical characterization of the normal and neoplastic brown bullhead skin to assess its suitability as a model of skin carcinogenesis. Brown bullhead were removed from Back River in the Chesapeake Bay region, an area historically polluted with heavy metals and polycyclic aromatic hydrocarbons. Histology, histochemistry, and electron microscopy were used to stage the morphologic development and progression of neoplasia in skin. The distribution of keratin, a family of structural proteins with altered expression in mammalian tumorigenesis, was analyzed with one and two dimensional gel electrophoresis and nitrocellulose blots of extracts from normal skin. Keratin expression in skin and other organs was also assessed with immunohistochemistry using AE1, AE3, and PCK 26 antibodies, and the proliferation index in skin and neoplasms with PCNA antibody. Skin lesions appeared to progress from hyperplasia through carcinoma, and the proliferation index was increased in papilloma. Also in papilloma, intercellular interdigitations appeared increased and desmosomes decreased which may in future studies correlate with changes in expression of other molecular markers of neoplastic progression. Both Type I and Type II keratin subfamilies were detected in skin using gel electrophoresis with the complimentary keratin blot-binding assay. For further development of the brown bullhead model, future studies can compare and relate these baseline data to alterations in expression of keratin and other markers in fish neoplasms and to molecular events which occur in man. PMID:10930121

  8. Sensitization to cereals and peanut evidenced by skin prick test and specific IgE in food-tolerant, grass pollen allergic patients

    Directory of Open Access Journals (Sweden)

    Martens Maria

    2011-12-01

    Full Text Available Abstract Background The botanical relation between grass and cereal grains may be relevant when diagnosing food allergy to cereals. The aim was to investigate the diagnostic specificity of skin prick test (SPT and specific immunoglobulin E (sIgE tests to cereals and peanut in grass pollen allergic subjects without history of, and clinically reactions to foods botanically related to grass. Methods 70 subjects (41 females; mean age 32 years and 20 healthy controls (13 females; mean age 24 years were tested by open food challenge (OFC with cereals and peanut. SPT and sIgE both with Immulite® (Siemens and ImmunoCAP® (Phadia to grass and birch pollen, cereals, peanut and bromelain were performed. Results Of the 65 OFC-negative subjects 29-46% (SPT, depending on cut-off, 20% (Immulite and 38% (ImmunoCAP had positive results to one or more of the foods tested. Controls were negative in all tests. Cross-reactive carbohydrate determinants (CCD as evidenced by reaction to bromelain could explain only a minority of the measured IgE-sensitizations. Conclusion Grass pollen allergic patients with documented food tolerance to cereals and peanut may express significant sensitization. False-positive cereal or peanut allergy diagnoses may be a quantitatively important problem both in routine clinical work and epidemiological studies.

  9. A sensitive LC-ESI-MS/MS method for the quantification of avobenzone in rat plasma and skin layers: Application to a topical administration study.

    Science.gov (United States)

    Kim, Min Gi; Kim, Tae Hwan; Shin, Beom Soo; Kim, Min Gyu; Seok, Su Hyun; Kim, Kyu-Bong; Lee, Jong Bong; Choi, Hyeon Gwan; Lee, Young Sung; Yoo, Sun Dong

    2015-10-15

    This study describes the development of a sensitive high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantification of avobenzone in rat plasma and skin layers. Separations were performed on a Zorbax SB C8 column using a binary gradient mobile phase composed of acetonitrile and 0.1% formic acid in water. The assay achieved LLOQ of 0.5ng/ml for plasma, 5ng/ml for stratum corneum, and 10ng/ml for epidermis and dermis. This method was applied to a percutaneous absorption study of avobenzone in rats. At 12h following topical application of emulsion and lotion (applied amount of avobenzone 11.7mg/kg), avobenzone was found primarily in the stratum corneum (16.3-17.8%) followed by epidermis (2.0-3.4%) and dermis (0.11-0.15%). Avobenzone was not quantifiable in the plasma samples collected over a 12h sampling period. Given the excellent plasma assay sensitivity, this study provides evidence that the systemic absorption of avobenzone is insignificant, if any, after topical application. PMID:26409261

  10. Fast variance reduction for steady-state simulation and sensitivity analysis of stochastic chemical systems using shadow function estimators

    Science.gov (United States)

    Milias-Argeitis, Andreas; Lygeros, John; Khammash, Mustafa

    2014-07-01

    We address the problem of estimating steady-state quantities associated to systems of stochastic chemical kinetics. In most cases of interest, these systems are analytically intractable, and one has to resort to computational methods to estimate stationary values of cost functions. In this work, we introduce a novel variance reduction algorithm for stochastic chemical kinetics, inspired by related methods in queueing theory, in particular the use of shadow functions. Using two numerical examples, we demonstrate the efficiency of the method for the calculation of steady-state parametric sensitivities and evaluate its performance in comparison to other estimation methods.

  11. In vivo observation of age-related structural changes of dermal collagen in human facial skin using collagen-sensitive second harmonic generation microscope equipped with 1250-nm mode-locked Cr:Forsterite laser

    Science.gov (United States)

    Yasui, Takeshi; Yonetsu, Makoto; Tanaka, Ryosuke; Tanaka, Yuji; Fukushima, Shu-ichiro; Yamashita, Toyonobu; Ogura, Yuki; Hirao, Tetsuji; Murota, Hiroyuki; Araki, Tsutomu

    2013-03-01

    In vivo visualization of human skin aging is demonstrated using a Cr:Forsterite (Cr:F) laser-based, collagen-sensitive second harmonic generation (SHG) microscope. The deep penetration into human skin, as well as the specific sensitivity to collagen molecules, achieved by this microscope enables us to clearly visualize age-related structural changes of collagen fiber in the reticular dermis. Here we investigated intrinsic aging and/or photoaging in the male facial skin. Young subjects show dense distributions of thin collagen fibers, whereas elderly subjects show coarse distributions of thick collagen fibers. Furthermore, a comparison of SHG images between young and elderly subjects with and without a recent life history of excessive sun exposure show that a combination of photoaging with intrinsic aging significantly accelerates skin aging. We also perform image analysis based on two-dimensional Fourier transformation of the SHG images and extracted an aging parameter for human skin. The in vivo collagen-sensitive SHG microscope will be a powerful tool in fields such as cosmeceutical sciences and anti-aging dermatology.

  12. LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. 2: Code description and usage

    Science.gov (United States)

    Radhakrishnan, Krishnan; Bittker, David A.

    1994-01-01

    LSENS, the Lewis General Chemical Kinetics Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 2 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 2 describes the code, how to modify it, and its usage, including preparation of the problem data file required to execute LSENS. Code usage is illustrated by several example problems, which further explain preparation of the problem data file and show how to obtain desired accuracy in the computed results. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions. Part 1 (NASA RP-1328) derives the governing equations describes the numerical solution procedures for the types of problems that can be solved by lSENS. Part 3 (NASA RP-1330) explains the kinetics and kinetics-plus-sensitivity-analysis problems supplied with LSENS and presents sample results.

  13. Aging changes in skin

    Science.gov (United States)

    ... areas. Changes in the connective tissue reduce the skin's strength and elasticity. This is known as elastosis. It is more ... chemicals Indoor heating Sunlight can cause: Loss of elasticity ... growths (keratoacanthomas) Pigment changes such as liver spots ...

  14. The association between null mutations in the filaggrin gene and contact sensitization to nickel and other chemicals in the general population

    DEFF Research Database (Denmark)

    Thyssen, J P; Johansen, J D; Linneberg, A;

    2010-01-01

    It was recently shown that filaggrin gene (FLG) null mutations are positively associated with nickel sensitization. We have hypothesized that histidine-rich filaggrin proteins in the epidermis chelate nickel ions and prevent their skin penetration and exposure to Langerhans cells. Furthermore, we...

  15. New formulation of chemical peeling agent: 30% salicylic acid in polyethylene glycol. Absorption and distribution of 14C-salicylic acid in polyethylene glycol applied topically to skin of hairless mice.

    Science.gov (United States)

    Ueda, Setsuko; Mitsugi, Koichi; Ichige, Kazumi; Yoshida, Kenji; Sakuma, Tomoko; Ninomiya, Shin-ichi; Sudou, Tetsuji

    2002-04-01

    Salicylic acid is used in chemical peeling procedures. However, they have caused many side effects, even salicylism. To achieve a salicylic acid peeling that would be safer for topical use, we recently developed a new formulation consisting of 30% salicylic acid in polyethylene glycol (PEG) vehicle. In an extension of our previous research, we studied the absorption of 30% salicylic acid labeled with 14C in PEG vehicle applied topically to the intact and damaged skin of male hairless mice. An ointment containing 3 mg salicylic acid in 10 mg vehicle was applied to both groups. In animals with intact skin, 1 h after application the plasma concentration of radioactivity was 1665.1 ng eq/ml, significantly lower than the 21437.6 ng eq/ml observed in mice with damaged skin. Microautoradiograms of intact skin showed that the level of radioactivity in the cornified cell layer was similar at 6 h after application. However, in damaged skin, the overall level of radioactivity showed a decrease by 3 h after application. In the carcasses remaining after the treated intact and damaged skin had been removed, 0.09 and 11.38% of the applied radioactivity remained, respectively. These findings confirm that 30% salicylic acid in PEG vehicle is little absorbed through the intact skin of hairless mice, and suggest that salicylism related to absorption through the skin of quantities of topically applied salicylic acid is not likely to occur in humans with intact skin during chemical peeling with this preparation. This new preparation of 30% salicylic acid in PEG vehicle is believed to be safe for application as a chemical peeling agent.

  16. Few Associations Found between Mold and Other Allergen Concentrations in the Home versus Skin Sensitivity from Children with Asthma after Hurricane Katrina in the Head-Off Environmental Asthma in Louisiana Study

    Directory of Open Access Journals (Sweden)

    L. F. Grimsley

    2012-01-01

    Full Text Available Mold and other allergen exposures exacerbate asthma symptoms in sensitized individuals. We evaluated allergen concentrations, skin test sensitivities, and asthma morbidity for 182 children, aged 4–12 years, with moderate to severe asthma, enrolled 18 months after Katrina, from the city of New Orleans and the surrounding parishes that were impacted by the storm, into the Head-off Environmental Asthma in Louisiana (HEAL observational study. Dust (indoor and air (indoor and outdoor samples were collected at baseline of 6 and 12 months. Dust samples were evaluated for dust mite, cockroach, mouse, and Alternaria by immunoassay. Air samples were evaluated for airborne mold spore concentrations. Overall, 89% of the children tested positive to ≥1 indoor allergen, with allergen-specific sensitivities ranging from 18% to 67%. Allergen concentration was associated with skin sensitivity for 1 of 10 environmental triggers analyzed (cat. Asthma symptom days did not differ with skin test sensitivity, and surprisingly, increased symptoms were observed in children whose baseline indoor airborne mold concentrations were below median levels. This association was not observed in follow-up assessments. The lack of relationship among allergen levels (including mold, sensitivities, and asthma symptoms points to the complexity of attempting to assess these associations during rapidly changing social and environmental conditions.

  17. Sensitivity of neuroprogenitor cells to chemical-induced apoptosis using a multiplexed assay suitable for high-throughput screening

    International Nuclear Information System (INIS)

    High-throughput methods are useful for rapidly screening large numbers of chemicals for biological activity, including the perturbation of pathways that may lead to adverse cellular effects. In vitro assays for the key events of neurodevelopment, including apoptosis, may be used in a battery of tests for detecting chemicals that could result in developmental neurotoxicity. Apoptosis contributes to nervous system development by regulating the size of the neuroprogenitor cell pool, and the balance between cellular proliferation and apoptosis during neuroprogenitor cell proliferation helps to determine the size and shape of the nervous system. Therefore, chemicals that affect apoptosis during neuronal development can have deleterious effects on the developing brain. The present study examined the utility of a high-throughput assay to detect chemical-induced apoptosis in mouse or human neuroprogenitor cells, as well as differentiated human neurons derived from induced pluripotent stem cells. Apoptosis was assessed using an assay that measures enzymatic activity of caspase-3/7 in a rapid and cost efficient manner. The results show that all three commercially available models generated a robust source of proliferating neuroprogenitor cells, and that the assay was sensitive and reproducible when used in a multi-well plate format. There were differences in the response of rodent and human neuroprogenitor cells to a set of chemicals previously shown to induce apoptosis in vitro. Neuroprogenitor cells were more sensitive to chemical-induced apoptosis than differentiated neurons, suggesting that neuroprogenitor cells are one of the cell models that should be considered for use in a developmental neurotoxicity screening battery

  18. High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

    Science.gov (United States)

    MacLeod, Neil A.; Weidmann, Damien

    2016-05-01

    High sensitivity detection, identification and quantification of chemicals in a stand-off configuration is a highly sought after capability across the security and defense sector. Specific applications include assessing the presence of explosive related materials, poisonous or toxic chemical agents, and narcotics. Real world field deployment of an operational stand-off system is challenging due to stringent requirements: high detection sensitivity, stand-off ranges from centimeters to hundreds of meters, eye-safe invisible light, near real-time response and a wide chemical versatility encompassing both vapor and condensed phase chemicals. Additionally, field deployment requires a compact, rugged, power efficient, and cost-effective design. To address these demanding requirements, we have developed the concept of Active Coherent Laser Spectrometer (ACLaS), which can be also described as a middle infrared hyperspectral coherent lidar. Combined with robust spectral unmixing algorithms, inherited from retrievals of information from high-resolution spectral data generated by satellitebased spectrometers, ACLaS has been demonstrated to fulfil the above-mentioned needs. ACLaS prototypes have been so far developed using quantum cascade lasers (QCL) and interband cascade lasers (ICL) to exploit the fast frequency tuning capability of these solid state sources. Using distributed feedback (DFB) QCL, demonstration and performance analysis were carried out on narrow-band absorbing chemicals (N2O, H2O, H2O2, CH4, C2H2 and C2H6) at stand-off distances up to 50 m using realistic non cooperative targets such as wood, painted metal, and bricks. Using more widely tunable external cavity QCL, ACLaS has also been demonstrated on broadband absorbing chemicals (dichloroethane, HFC134a, ethylene glycol dinitrate and 4-nitroacetanilide solid) and on complex samples mixing narrow-band and broadband absorbers together in a realistic atmospheric background.

  19. Sensitivity of Satellite-Based Skin Temperature to Different Surface Emissivity and NWP Reanalysis Sources Demonstrated Using a Single-Channel, Viewing-Angle-Corrected Retrieval Algorithm

    Science.gov (United States)

    Scarino, B. R.; Minnis, P.; Yost, C. R.; Chee, T.; Palikonda, R.

    2015-12-01

    Single-channel algorithms for satellite thermal-infrared- (TIR-) derived land and sea surface skin temperature (LST and SST) are advantageous in that they can be easily applied to a variety of satellite sensors. They can also accommodate decade-spanning instrument series, particularly for periods when split-window capabilities are not available. However, the benefit of one unified retrieval methodology for all sensors comes at the cost of critical sensitivity to surface emissivity (ɛs) and atmospheric transmittance estimation. It has been demonstrated that as little as 0.01 variance in ɛs can amount to more than a 0.5-K adjustment in retrieved LST values. Atmospheric transmittance requires calculations that employ vertical profiles of temperature and humidity from numerical weather prediction (NWP) models. Selection of a given NWP model can significantly affect LST and SST agreement relative to their respective validation sources. Thus, it is necessary to understand the accuracies of the retrievals for various NWP models to ensure the best LST/SST retrievals. The sensitivities of the single-channel retrievals to surface emittance and NWP profiles are investigated using NASA Langley historic land and ocean clear-sky skin temperature (Ts) values derived from high-resolution 11-μm TIR brightness temperature measured from geostationary satellites (GEOSat) and Advanced Very High Resolution Radiometers (AVHRR). It is shown that mean GEOSat-derived, anisotropy-corrected LST can vary by up to ±0.8 K depending on whether CERES or MODIS ɛs sources are used. Furthermore, the use of either NOAA Global Forecast System (GFS) or NASA Goddard Modern-Era Retrospective Analysis for Research and Applications (MERRA) for the radiative transfer model initial atmospheric state can account for more than 0.5-K variation in mean Ts. The results are compared to measurements from the Surface Radiation Budget Network (SURFRAD), an Atmospheric Radiation Measurement (ARM) Program ground

  20. Studying one-dimensional characteristics of gamma-families, sensitive to chemical composition of cosmic rays in region of ultrahigh energies

    International Nuclear Information System (INIS)

    A definition of chemical composition of primary cosmic rays (PCR) is an important problem in interpretation of experimental results with X-ray emulsion chambers (XREC). In this work the parameters, sensitive to chemical compositions of PCR, are analyzed by XREC method. A number of parameters of the gamma-families formed in PCR by primary protons and nuclei are considered and sensitivity of γ-family parameters to chemical composition of PCR is obtained. (authors)

  1. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    OpenAIRE

    Liu Yang; Qiang Han; Shuya Cao; Feng Huang; Molin Qin; Chenghai Guo; Mingyu Ding

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical an...

  2. The use of ex vivo human skin tissue for genotoxicity testing.

    Science.gov (United States)

    Reus, Astrid A; Usta, Mustafa; Krul, Cyrille A M

    2012-06-01

    As a result of the chemical legislation concerning the registration, evaluation, authorization and restriction of chemicals (REACH), and the Seventh Amendment to the Cosmetics Directive, which prohibits animal testing in Europe for cosmetics, alternative methods for safety evaluation of chemicals are urgently needed. Current in vitro genotoxicity assays are not sufficiently predictive for the in vivo situation, resulting in an unacceptably high number of misleading positives. For many chemicals and ingredients of personal care products the skin is the first site of contact, but there are no in vitro genotoxicity assays available in the skin for additional evaluation of positive or equivocal responses observed in regulatory in vitro genotoxicity assays. In the present study ex vivo human skin tissue obtained from surgery was used for genotoxicity evaluation of chemicals by using the comet assay. Fresh ex vivo human skin tissue was cultured in an air-liquid interface and topically exposed to 20 chemicals, including true positive, misleading positive and true negative genotoxins. Based on the results obtained in the present study, the sensitivity, specificity and accuracy of the ex vivo skin comet assay to predict in vivo genotoxicity were 89%, 90% and 89%, respectively. Donor and experimental variability were mainly reflected in the magnitude of the response and not the difference between the presence and absence of a genotoxic response. The present study indicates that human skin obtained from surgery is a promising and robust model for safety evaluation of chemicals that are in direct contact with the skin. PMID:22507867

  3. Xenobiotic metabolism capacities of human skin in comparison with a 3D epidermis model and keratinocyte-based cell culture as in vitro alternatives for chemical testing: activating enzymes (Phase I).

    Science.gov (United States)

    Götz, Christine; Pfeiffer, Roland; Tigges, Julia; Blatz, Veronika; Jäckh, Christine; Freytag, Eva-Maria; Fabian, Eric; Landsiedel, Robert; Merk, Hans F; Krutmann, Jean; Edwards, Robert J; Pease, Camilla; Goebel, Carsten; Hewitt, Nicola; Fritsche, Ellen

    2012-05-01

    Skin is important for the absorption and metabolism of exposed chemicals such as cosmetics or pharmaceuticals. The Seventh Amendment to the EU Cosmetics Directive prohibits the use of animals for cosmetic testing for certain endpoints, such as genotoxicity; therefore, there is an urgent need to understand the xenobiotic metabolizing capacities of human skin and to compare these activities with reconstructed 3D skin models developed to replace animal testing. We have measured Phase I enzyme activities of cytochrome P450 (CYP) and cyclooxygenase (COX) in ex vivo human skin, the 3D skin model EpiDerm™ (EPI-200), immortalized keratinocyte-based cell lines and primary normal human epidermal keratinocytes. Our data demonstrate that basal CYP enzyme activities are very low in whole human skin and EPI-200 as well as keratinocytes. In addition, activities in monolayer cells differed from organotypic tissues after induction. COX activity was similar in skin, EPI-200 and NHEK cells, but was significantly lower in immortalized keratinocytes. Hence, the 3D model EPI-200 might represent a more suitable model for dermatotoxicological studies. Altogether, these data help to better understand skin metabolism and expand the knowledge of in vitro alternatives used for dermatotoxicity testing. PMID:22509833

  4. Chemical Peels

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... Chemical peels public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  5. Aging Skin

    Science.gov (United States)

    ... email address Submit Home > Healthy Aging > Wellness Healthy Aging Aging skin More information on aging skin When it ... treated early. Return to top More information on Aging skin Read more from womenshealth.gov Varicose Veins ...

  6. Skin Conditions

    Science.gov (United States)

    Your skin is your body's largest organ. It covers and protects your body. Your skin Holds body fluids in, preventing dehydration Keeps harmful ... it Anything that irritates, clogs, or inflames your skin can cause symptoms such as redness, swelling, burning, ...

  7. Evaluation of a Novel Rapid Test System for the Detection of Allergic Sensitization to Timothy Grass Pollen against Established Laboratory Methods and Skin Prick Test

    Directory of Open Access Journals (Sweden)

    R. Lucassen

    2010-01-01

    Full Text Available Type I hypersensitivity is driven by allergen specific immunoglobulin E (sIgE and thus sIgE represents a marker for modern allergy diagnosis. Recently, a rapid assay for the detection of sIgE, termed as (Allergy Lateral Flow Assay ALFA, has been developed. The objective of our study is the evaluation of a scanner-based system for the semiquantitative interpretation of ALFA results. Agreement to Skin Prick Test (SPT, Allergopharma, ALLERG-O-LIQ System (Dr. Fooke, and ImmunoCAP (Phadia was investigated using 50 sera tested for specific IgE to timothy grass pollen (g6. 35/50 sera were positive by SPT, ALLERG-O-LIQ, and ImmunoCAP. Excellent agreement was observed between ALFA results and SPT, ImmunoCAP, and ALLERG-O-LIQ. Area under the curve (AUC values were found at 1.0, and 100% sensitivity and specificity was found versus all other methods. Visual- and scanner-based interpretation of the ALFA results revealed excellent agreement.

  8. Sensitivity and specificity of the consumer open skin allergy test as a method of prediction of contact dermatitis to hair dyes.

    Science.gov (United States)

    Krasteva, Maya; Cottin, Martin; Cristaudo, Antonio; Lainé, Gérard; Nohynek, Gerhard; Orton, David; Toutain, Hervé; Severino, Vincenzo; Wilkinson, John

    2005-01-01

    To prevent contact dermatitis to oxidative hair colouring products, a consumer test (skin allergy test, SAT) consisting of the open application of the colourant base prior to mixing with the developer is recommended 48 hours before hair colouring. We investigated the sensitivity and specificity of the SAT to detect and prevent contact allergy to oxidative hair colouring products that contained a range of concentrations of para-phenylenediamine (PPD) and corresponded to different shades (light, medium and dark). Test colouring products containing increasing concentrations of PPD (0.1, 0.5, 1.0 or 1.5%) were applied to 34 PPD-positive hair dye-allergic individuals and to 49 non-allergic control subjects. Allergic reactions were elicited in all PPD-positive subjects whereas none occurred in control PPD-negative subjects. For each subject the eliciting concentration of PPD in the SAT was compared with the PPD concentration range of the group of commercial shades reported as causing reactions by the consumer. In all PPD-positive subjects the eliciting concentrations of PPD in the SAT was within or lower than the range of PPD concentrations in the reported eliciting colourant base of commercial products. In conclusion, our results confirm the excellent predictive value of the SAT over the entire range of PPD concentrations used in oxidative hair colouring products and suggest that the test is a suitable tool for the secondary prevention of contact allergic reactions to hair colouring products. PMID:15701588

  9. A comparison of chemical shift sensitivity of trifluoromethyl tags: optimizing resolution in {sup 19}F NMR studies of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Libin; Larda, Sacha Thierry; Frank Li, Yi Feng [University of Toronto, UTM, Department of Chemistry (Canada); Manglik, Aashish [Stanford University School of Medicine, Department of Molecular and Cellular Physiology (United States); Prosser, R. Scott, E-mail: scott.prosser@utoronto.ca [University of Toronto, UTM, Department of Chemistry (Canada)

    2015-05-15

    The elucidation of distinct protein conformers or states by fluorine ({sup 19}F) NMR requires fluorinated moieties whose chemical shifts are most sensitive to subtle changes in the local dielectric and magnetic shielding environment. In this study we evaluate the effective chemical shift dispersion of a number of thiol-reactive trifluoromethyl probes [i.e. 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide (BTFMA), N-(4-bromo-3-(trifluoromethyl)phenyl)acetamide (3-BTFMA), 3-bromo-1,1,1-trifluoropropan-2-ol (BTFP), 1-bromo-3,3,4,4,4-pentafluorobutan-2-one (BPFB), 3-bromo-1,1,1-trifluoropropan-2-one (BTFA), and 2,2,2-trifluoroethyl-1-thiol (TFET)] under conditions of varying polarity. In considering the sensitivity of the {sup 19}F NMR chemical shift to the local environment, a series of methanol/water mixtures were prepared, ranging from relatively non-polar (MeOH:H{sub 2}O = 4) to polar (MeOH:H{sub 2}O = 0.25). {sup 19}F NMR spectra of the tripeptide, glutathione ((2S)-2-amino-4-{[(1R)-1-[(carboxymethyl)carbamoyl] -2-sulfanylethyl]carbamoyl}butanoic acid), conjugated to each of the above trifluoromethyl probes, revealed that the BTFMA tag exhibited a significantly greater range of chemical shift as a function of solvent polarity than did either BTFA or TFET. DFT calculations using the B3LYP hybrid functional and the 6-31G(d,p) basis set, confirmed the observed trend in chemical shift dispersion with solvent polarity.

  10. Analysis of the Local Lymph Node Assay (LLNA) variability for assessing the prediction of skin sensitisation potential and potency of chemicals with non-animal approaches.

    Science.gov (United States)

    Dumont, Coralie; Barroso, João; Matys, Izabela; Worth, Andrew; Casati, Silvia

    2016-08-01

    The knowledge of the biological mechanisms leading to the induction of skin sensitisation has favoured in recent years the development of alternative non-animal methods. During the formal validation process, results from the Local Lymph Node Assay (LLNA) are generally used as reference data to assess the predictive capacity of the non-animal tests. This study reports an analysis of the variability of the LLNA for a set of chemicals for which multiple studies are available and considers three hazard classification schemes: POS/NEG, GHS/CLP and ECETOC. As the type of vehicle used in a LLNA study is known to influence to some extent the results, two analyses were performed: considering the solvent used to test the chemicals and without considering the solvent. The results show that the number of discordant classifications increases when a chemical is tested in more than one solvent. Moreover, it can be concluded that study results leading to classification in the strongest classes (1A and EXT) seem to be more reliable than those in the weakest classes. This study highlights the importance of considering the variability of the reference data when evaluating non-animal tests. PMID:27085510

  11. Chemical derivatization for enhancing sensitivity during LC/ESI-MS/MS quantification of steroids in biological samples: a review.

    Science.gov (United States)

    Higashi, Tatsuya; Ogawa, Shoujiro

    2016-09-01

    Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are necessary for the diagnosis, pathological analysis and treatment of many diseases. Recently, liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been widely used for these purposes due to its specificity and versatility. However, the ESI efficiency and fragmentation behavior of some steroids are poor, which lead to a low sensitivity. Chemical derivatization is one of the most effective methods to improve the detection characteristics of steroids in ESI-MS/MS. Based on this background, this article reviews the recent advances in chemical derivatization for the trace quantification of steroids in biological samples by LC/ESI-MS/MS. The derivatization in ESI-MS/MS is based on tagging a proton-affinitive or permanently charged moiety on the target steroid. Introduction/formation of a fragmentable moiety suitable for the selected reaction monitoring by the derivatization also enhances the sensitivity. The stable isotope-coded derivatization procedures for the steroid analysis are also described. PMID:26454158

  12. Mindfulness-based cognitive therapy (MBCT) for multiple chemical sensitivity (MCS)

    DEFF Research Database (Denmark)

    Hauge, Christian Riise; Rasmussen, Alice; Piet, Jacob;

    2015-01-01

    the effects of mindfulness-based cognitive therapy (MBCT) for individuals with MCS. METHODS: The intention-to-treat sample (ITT) included 69 individuals who had been randomized to either MBCT or treatment as usual (TAU). The primary outcome measure was the Quick Environmental Exposure and Sensitivity...

  13. Non-allergic cutaneous reactions in airborne chemical sensitivity--a population based study

    DEFF Research Database (Denmark)

    Linneberg, Allan; Thyssen, Jacob Pontoppidan; Dirksen, Asger;

    2011-01-01

    sensitivity. Associations were controlled for the possible confounding effects of sex, age, asthma, eczema, atopic dermatitis, psychological and social factors, and smoking habits. In unadjusted analyses we found associations between allergic and non-allergic cutaneous reactions on patch testing and the two...

  14. Electro chemical Aptasensor Based on Prussian Blue-Chitosan-Glutaraldehyde for the Sensitive Determination of Tetracycline

    Institute of Scientific and Technical Information of China (English)

    Guanghui Shen; Yemin Guo; Xia Sun∗; Xiangyou Wang

    2014-01-01

    In this paper, a novel and sensitive electrochemical aptasensor for detecting tetracycline (TET) with prussian blue (PB) as the label-free signal was fabricated. A PB-chitosan-glutaraldehyde (PB-CS-GA) system acting as the signal indicator was developed to improve the sensitivity of the electrochemical aptasensor. Firstly, the PB-CS-GA was fixed onto the glass carbon electrode surface. Then, colloidal gold nanoparticles (AuNPs) were droped onto the electrode to immobilize the anti-TET aptamer for preparation of the aptasensor. The stepwise assembly process of the aptasensor was characterized by cyclic voltammetry (C-V) and scanning electron microscope (SEM). The target TET captured onto the electrode induced the current response of the electrode due to the non-conducting biomoleculars. Under the optimum operating conditions, the response of differential pulse voltammetry (DPV) was used for detecting the concentration of TET. The proposed aptasensor showed a high sensitivity and a wide linear range of 10−9 ∼ 10−5 M and 10−5 ∼ 10−2 M with the correlation coefficients of 0.994 and 0.992, respectively. The detection limit was 3.2×10−10 M (RSD 4.12%). Due to its rapidity, sensitivity and low cost, the proposed aptasensor could be used as a pre-scanning method in TET determination for the analysis of livestock products.

  15. Correlating chemical sensitivity and basal gene expression reveals mechanism of action | Office of Cancer Genomics

    Science.gov (United States)

    Changes in cellular gene expression in response to small-molecule or genetic perturbations have yielded signatures that can connect unknown mechanisms of action (MoA) to ones previously established. We hypothesized that differential basal gene expression could be correlated with patterns of small-molecule sensitivity across many cell lines to illuminate the actions of compounds whose MoA are unknown.

  16. Sensitivity analysis of large system of chemical kinetic parameters for engine combustion simulation

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, H; Sanz-Argent, J; Petitpas, G; Havstad, M; Flowers, D

    2012-04-19

    In this study, the authors applied the state-of-the art sensitivity methods to downselect system parameters from 4000+ to 8, (23000+ -> 4000+ -> 84 -> 8). This analysis procedure paves the way for future works: (1) calibrate the system response using existed experimental observations, and (2) predict future experiment results, using the calibrated system.

  17. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    Science.gov (United States)

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-01

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs. PMID:24678766

  18. A REVIEW ON SKIN CANCER

    OpenAIRE

    S. Ramya Silpa; Chidvila V

    2013-01-01

    Skin cancer can be of 2 types mainly. They are malignant melanoma and non-malignant melanoma. Skin cancer mainly occurs due to exposure of sunlight. Ozone depletion and chemical exposures are other factors involved in precipitating skin cancer. Mutations of p53 gene are involved in UV- induced carcinogenesis. P53 gene acts vital in development of SCC. So, prevention of skin cancer is the main criteria. Regular application of sunscreens could be one of the primary prevention. The purpose of pr...

  19. Sensitivities of Two Zebrafish TRPA1 Paralogs to Chemical and Thermal Stimuli Analyzed in Heterologous Expression Systems.

    Science.gov (United States)

    Oda, Mai; Kurogi, Mako; Kubo, Yoshihiro; Saitoh, Osamu

    2016-03-01

    Transient receptor potential A1 (TRPA1) is the only member of the mouse, chick, and frog TRPA family, whereas 2 paralogs (zTRPA1a and zTRPA1b) are present in zebrafish. We herein investigated functional differences in the 2 zebrafish TRPA1s. HEK293T cells were used as heterologous expression systems, and the sensitivities of these cells to 4 chemical irritants (allyl isothiocyanate [AITC], caffeine, auto-oxidized epigallocatechin gallate [EGCG], and hydrogen peroxide [H2O2]) were compared with Ca(2+) imaging techniques. Sensitivities to the activators for AITC, oxidized EGCG, and H2O2 were higher in cells expressing zTRPA1a than in those expressing zTRPA1b, whereas caffeine appeared to activate both cells equally. We also characterized the thermal sensitivity of Xenopus oocytes expressing each TRPA1 electrophysiologically using a 2-electrode voltage clamp. Although endogenous currents induced by a cold stimulation were observed in control oocytes in some batches, oocytes expressing zTRPA1b showed significantly stronger cold- and heat-induced responses. However, significant thermal activation was not observed in oocytes expressing zTRPA1a. The results obtained using in vitro expression systems suggest that zTRPA1a is specialized for chemical sensing, whereas zTRPA1b responds to thermal stimuli. Furthermore, characterization of the chimeric molecule of TRPA1a and 1b revealed the importance of the N-terminal region in chemical and thermal sensing by zTRPA1s. PMID:26826723

  20. Sensitivity of chemical reaction networks: a structural approach 3. Regular multimolecular systems

    CERN Document Server

    Brehm, Bernhard

    2016-01-01

    We present a systematic mathematical analysis of the qualitative steady-state response to rate perturbations in large classes of reaction networks. This includes multimolecular reactions and allows for catalysis, enzymatic reactions, multiple reaction products, nonmonotone rate functions, and non-closed autonomous systems. Our structural sensitivity analysis is based on the stoichiometry of the reaction network, only. It does not require numerical data on reaction rates. Instead, we impose mild and generic nondegeneracy conditions of algebraic type. From the structural data, only, we derive which steady-state concentrations are sensitive to, and hence influenced by, changes of any particular reaction rate - and which are not. We also establish transitivity properties for influences involving rate perturbations. This allows us to derive an influence graph which globally summarizes the influence pattern of the given network. The influence graph allows the computational, but meaningful, automatic identification ...

  1. Porous solgel fiber as a transducer for highly sensitive chemical sensing.

    Science.gov (United States)

    Tao, Shiquan; Winstead, Christopher B; Singh, Jagdish P; Jindal, Rajeev

    2002-08-15

    A novel solgel process for making porous silica fiber and doping the fiber core with sensing material is described. A CoCl(2) -doped solgel fiber was fabricated and was used to construct an active-core optical fiber moisture sensor. Test results show that the sensitivity of the active-core optical fiber sensor is much higher than that of an evanescent-wave-based optical fiber sensor. PMID:18026453

  2. Bitter-sensitive gustatory receptor neuron responds to chemically diverse insect repellents in the common malaria mosquito Anopheles quadrimaculatus

    Science.gov (United States)

    Sparks, Jackson T.; Dickens, Joseph C.

    2016-06-01

    Female mosquitoes feed on blood from animal hosts to obtain nutritional resources used for egg production. These contacts facilitate the spread of harmful human diseases. Chemical repellents are used to disrupt mosquito host-seeking and blood-feeding behaviors; however, little is known about the gustatory sensitivity of mosquitoes to known repellents. Here, we recorded electrical responses from gustatory receptor neurons (GRNs) housed within the labellar sensilla of female Anopheles quadrimaculatus to N,N-diethyl-3-methylbenzamide (DEET), picaridin, IR3535, 2-undecanone, p-menthane-3,8-diol, geraniol, trans-2-hexen-1-ol, quinine, and quinidine. A bitter-sensitive GRN responded to all tested repellents and quinine, a known feeding deterrent. Responses of the bitter-sensitive neuron to quinine and an isomer, quinidine, did not differ. Delayed bursts of electrical activity were observed in response to continuous stimulation with synthetic repellents at high concentrations. Electrophysiological recordings from bitter-sensitive GRNs associated with mosquito gustatory sensilla represent a convenient model to evaluate candidate repellents.

  3. Bilayer ZnO nanostructure fabricated by chemical bath and its application in quantum dot sensitized solar cell

    International Nuclear Information System (INIS)

    Chemical bath method was used to synthesize bilayer ZnO nanostructure on ITO glass in the alkaline solution. As revealed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the product consists of a layered structure of ZnO nanorods at the bottom and nanoflower atop. The as-prepared sample was assembled in quantum dot sensitized solar cell (QDSSC), which obtained the incident photon to current conversion efficiency (IPCE) of 15% at 400 nm and power conversion efficiency (PCE) of 0.45%. Therefore, this novel bilayer ZnO nanostructure has the potential for application in solar cell device as the photoelectrode.

  4. Anti-tumor activity of Phyllanthus niruri (a medicinal plant) on chemical-induced skin carcinogenesis in mice.

    Science.gov (United States)

    Sharma, Priyanka; Parmar, Jyoti; Verma, Preeti; Sharma, Priyanka; Goyal, P K

    2009-01-01

    Chemoprevention is an important strategy to control the process of carcinogenesis. The potential of using medicinal herbs as cancer chemopreventive nutraceuticals and functional food is promising. Thus, there is a need for exploring drugs/agents which act as chemopreventive agents. Phyllanthus niruri is a well known medicinal plant which has been used in Ayurvedic medicine as hepatoprotective, antiviral, antibacterial, analgesic, antispasmodic and antidiabetic. The present study was carried out to evaluate the anti-tumor activity of a hydro-alcoholic extract of the whole plant, in 7-9 week old male Swiss albino mice, on the two stage process of skin carcinogenesis induced by a single topical application of 7, 12-dimethylbenz (a)anthracene (100 microg/100 microl acetone) and two weeks later promoted by repeated application of croton oil (1% in acetone/three times a week) till the end of experiment (16 weeks). The oral administration of P. niruri at a dose of 1000 mg/kg/b.wt. at peri- (i.e. 7 days before and 7 days after DMBA application) and post- (i.e. starting from the croton oil application) initiational phase of papillomagenesis caused significant reduction in tumor incidence, tumor yield, tumor burden and cumulative number of papillomas as compared to carcinogen-treated controls. Furthermore, the average latent period was significantly increased in the PNE treated group. The results thus suggest that P. niruri extract exhibits significant anti-tumor activity, which supports the traditional medicinal utilization of this plant. PMID:20192590

  5. In chemico evaluation of prohapten skin sensitizers: behavior of 2-methoxy-4-(¹³C)methylphenol in the peroxidase peptide reactivity assay (PPRA) as an alternative to animal testing.

    Science.gov (United States)

    Merckel, Fabien; Giménez-Arnau, Elena; Gerberick, G Frank; Lepoittevin, Jean-Pierre

    2013-04-26

    In chemico methods, based on the assessment of a hapten's reactivity toward peptides, have been proposed as alternative methods for the assessment of the skin sensitizing potential of chemicals. However, even with these approaches showing promise, a major drawback is the activation of prohaptens, i.e. molecules needing a metabolic activation to become reactive and therefore sensitizing. Recently, it has been proposed to couple an enzymatic activation step based on horseradish peroxidase (HRP)/hydrogen peroxide to such peptide reactivity assays. To evaluate this approach, the behavior of 2-methoxy-4-methylphenol (2M4MP), reported as a moderate sensitizer according to the Local Lymph Node Assay (LLNA), has been investigated in this assay. To follow the reaction with the peptides and characterize more easily intermediates and adducts, the molecule was first (13)C isotopically substituted at the most probable reactive position. When 2M4MP was incubated with HRP/H2O2 in a mixture PBS (pH 7.4, 0.1M)/acetonitrile 2:1, two main products were formed deriving from the formation of a quinone methide 2M4MQ subsequently trapped by either H2O2 or H2O to form a benzylic hydroperoxide or alcohol, respectively. When nucleophiles such as GSH or a peptide containing a cysteine residue (Pep-Cys) were present in the reaction medium, the quinone methide 2M4MQ was trapped by the more nucleophilic thiol function to form thio-adducts. No modifications of 2M4MP were observed when the same reactions were carried out without HRP confirming that the activation of the molecule was enzyme related. Amino nucleophiles were shown to be far less reactive towards the quinone methide 2M4MQ with only tiny formation of adducts with lysine or arginine side chains. In addition we demonstrated that the same enzymatic activation could also take place in a microemulsion based on sodium dodecyl sulfate/tert-butanol/chloroform/buffer. PMID:23454653

  6. Skin Biomes.

    Science.gov (United States)

    Fyhrquist, N; Salava, A; Auvinen, P; Lauerma, A

    2016-05-01

    The cutaneous microbiome has been investigated broadly in recent years and some traditional perspectives are beginning to change. A diverse microbiome exists on human skin and has a potential to influence pathogenic microbes and modulate the course of skin disorders, e.g. atopic dermatitis. In addition to the known dysfunctions in barrier function of the skin and immunologic disturbances, evidence is rising that frequent skin disorders, e.g. atopic dermatitis, might be connected to a dysbiosis of the microbial community and changes in the skin microbiome. As a future perspective, examining the skin microbiome could be seen as a potential new diagnostic and therapeutic target in inflammatory skin disorders.

  7. Quantitative structure activity relationship model for predicting the depletion percentage of skin allergic chemical substances of glutathione.

    Science.gov (United States)

    Si, Hongzong; Wang, Tao; Zhang, Kejun; Duan, Yun-Bo; Yuan, Shuping; Fu, Aiping; Hu, Zhide

    2007-05-22

    A quantitative model was developed to predict the depletion percentage of glutathione (DPG) compounds by gene expression programming (GEP). Each kind of compound was represented by several calculated structural descriptors involving constitutional, topological, geometrical, electrostatic and quantum-chemical features of compounds. The GEP method produced a nonlinear and five-descriptor quantitative model with a mean error and a correlation coefficient of 10.52 and 0.94 for the training set, 22.80 and 0.85 for the test set, respectively. It is shown that the GEP predicted results are in good agreement with experimental ones, better than those of the heuristic method. PMID:17481417

  8. Correlating chemical sensitivity and basal gene expression reveals mechanism of action

    Science.gov (United States)

    Rees, Matthew G.; Seashore-Ludlow, Brinton; Cheah, Jaime H.; Adams, Drew J.; Price, Edmund V.; Gill, Shubhroz; Javaid, Sarah; Coletti, Matthew E.; Jones, Victor L.; Bodycombe, Nicole E.; Soule, Christian K.; Alexander, Benjamin; Li, Ava; Montgomery, Philip; Kotz, Joanne D.; Hon, C. Suk-Yee; Munoz, Benito; Liefeld, Ted; Dančík, Vlado; Haber, Daniel A.; Clish, Clary B.; Bittker, Joshua A.; Palmer, Michelle; Wagner, Bridget K.; Clemons, Paul A.; Shamji, Alykhan F.; Schreiber, Stuart L.

    2015-01-01

    Changes in cellular gene expression in response to small-molecule or genetic perturbations have yielded signatures that can connect unknown mechanisms of action (MoA) to ones previously established. We hypothesized that differential basal gene expression could be correlated with patterns of small-molecule sensitivity across many cell lines to illuminate the actions of compounds whose MoA are unknown. To test this idea, we correlated the sensitivity patterns of 481 compounds with ~19,000 basal transcript levels across 823 different human cancer cell lines and identified selective outlier transcripts. This process yielded many novel mechanistic insights, including the identification of activation mechanisms, cellular transporters, and direct protein targets. We found that ML239, originally identified in a phenotypic screen for selective cytotoxicity in breast cancer stem-like cells, most likely acts through activation of fatty acid desaturase 2 (FADS2). These data and analytical tools are available to the research community through the Cancer Therapeutics Response Portal. PMID:26656090

  9. A review of optimization and quantification techniques for chemical exchange saturation transfer MRI toward sensitive in vivo imaging.

    Science.gov (United States)

    Kim, Jinsuh; Wu, Yin; Guo, Yingkun; Zheng, Hairong; Sun, Phillip Zhe

    2015-01-01

    Chemical exchange saturation transfer (CEST) MRI is a versatile imaging method that probes the chemical exchange between bulk water and exchangeable protons. CEST imaging indirectly detects dilute labile protons via bulk water signal changes following selective saturation of exchangeable protons, which offers substantial sensitivity enhancement and has sparked numerous biomedical applications. Over the past decade, CEST imaging techniques have rapidly evolved owing to contributions from multiple domains, including the development of CEST mathematical models, innovative contrast agent designs, sensitive data acquisition schemes, efficient field inhomogeneity correction algorithms, and quantitative CEST (qCEST) analysis. The CEST system that underlies the apparent CEST-weighted effect, however, is complex. The experimentally measurable CEST effect depends not only on parameters such as CEST agent concentration, pH and temperature, but also on relaxation rate, magnetic field strength and more importantly, experimental parameters including repetition time, RF irradiation amplitude and scheme, and image readout. Thorough understanding of the underlying CEST system using qCEST analysis may augment the diagnostic capability of conventional imaging. In this review, we provide a concise explanation of CEST acquisition methods and processing algorithms, including their advantages and limitations, for optimization and quantification of CEST MRI experiments. PMID:25641791

  10. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    Science.gov (United States)

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  11. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat [Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia); Amin, Mohd. Cairul Iqbal Mohd [Faculty of Pharmacy, University Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia)

    2014-09-03

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  12. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    Science.gov (United States)

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat; Amin, Mohd. Cairul Iqbal Mohd

    2014-09-01

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  13. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    International Nuclear Information System (INIS)

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier

  14. Contact sensitizer nickel sulfate activates the transcription factors NF-kB and AP-1 and increases the expression of nitric oxide synthase in a skin dendritic cell line

    OpenAIRE

    Cruz, M. Teresa; Gonçalo, Margarida; Figueiredo, Américo; Carvalho, Arsélio P.; Duarte, Carlos B.; Lopes, M. Celeste

    2004-01-01

    Nuclear factor kappa B (NF-kB) and activating protein-1 (AP-1) transcription factors are ubiquitously expressed signaling molecules known to regulate the transcription of a large number of genes involved in immune responses, namely the inducible isoform of nitric oxide synthase (iNOS). In this study, we demonstrate that a fetal skin-derived dendritic cell line (FSDC) produces nitric oxide (NO) in response to the contact sensitizer nickel sulfate (NiSO4) and increases the ...

  15. Bifidobacterium longum lysate, a new ingredient for reactive skin.

    Science.gov (United States)

    Guéniche, Audrey; Bastien, Philippe; Ovigne, Jean Marc; Kermici, Michel; Courchay, Guy; Chevalier, Veronique; Breton, Lionel; Castiel-Higounenc, Isabelle

    2010-08-01

    Reactive skin is characterized by marked sensitivity to physical (heat, cold, wind) or chemical (topically applied products) stimuli and by the impairment of the skin barrier's ability to repair itself. Several lines of evidence suggest that beyond their capacity to positively influence the composition of intestinal microbiota, some probiotic bacteria can modulate the immune system both at local and systemic levels, thereby improving immune defense mechanisms and/or down-regulating immune disorders such as allergies and intestinal inflammation. Several recent human clinical trials clearly suggest that probiotic supplementation might be beneficial to the skin. Using a probiotic lysate, Bifidobacterium longum sp. extract (BL), we demonstrated first in vitro, and then in a clinical trial, that this non-replicating bacteria form applied to the skin was able to improve sensitive skin. The effect of BL were evaluated first on two different models. Using ex vivo human skin explant model we found a statistically significant improvement versus placebo in various parameters associated with inflammation such as a decrease in vasodilation, oedema, mast cell degranulation and TNF-alpha release. Moreover, using nerve cell cultures in vitro, we showed that after 6 h of incubation in culture medium (0.3-1%), the probiotic lysate significantly inhibited capsaicin-induced CGRP release by neurones. Then, a topical cream containing the active extract was tested in a randomized, double-blind, placebo-controlled trial. Sixty-six female volunteers with reactive skin were randomly given either the cream with the bacterial extract at 10% (n = 33) or the control cream (n = 33). The volunteers applied the cream to the face, arms and legs twice a day for two months. Skin sensitivity was assessed by stinging test (lactic acid) and skin barrier recovery was evaluated by measuring trans-epidermal water loss following barrier disruption induced by repeated tape-stripping at D1, D29 and D57. The

  16. 头孢曲松试敏液浓度对皮试结果的影响%Effect of Ceftriaxone Sensitive Test Solution Concentration on the Skin Test Results

    Institute of Scientific and Technical Information of China (English)

    赵艳梅

    2014-01-01

    目的:通过不同浓度试敏液对患者的测试,观察能否降低皮试的假阴性。方法选取无青霉素严重过敏史及头孢曲松无过敏史的患者400例,分别用浓度为1250 ug/mL和500 ug/mL的头孢曲松钠原液做皮试。用药以任一浓度皮试液皮试结果阴性为准,观察统计假阴性结果例数。结果浓度为500 ug/mL试敏液做皮试发现假阴性14例,所致过敏反应发生率7%;浓度为1250 ug/mL皮试发生假阴性结果9例,所致过敏反应率4.5%。两者相比较2=1.15,>0.05。结论不能证明提高头孢曲松钠试敏液浓度可降低皮试假阴性结果引起的过敏反应发生率。%Objective Through the dif erent concentration of test sensitivity test for patients, observe whether it can reduce false positive skin test. Methods Select without severe al ergies and ceftriaxone penicil in al ergy history of 400 cases of patients, respectively, with concentration of 1250 ug/ml and 500 ug/ml of ceftriaxone sodium concentrate to do skin test. Drugs to any concentration of skin test skin test result is negative, observation statistics were false negative results. Results The concentration of 500 ug/ml try sensitive liquid found 14 of the false negatives do skin test, al ergic reaction caused by the incidence of 7%; Concentration to 1250 ug/ml skin test in 9 cases of false negative results, caused by an al ergic reaction rate was 4.5%. Comparing the two X squared =1.15, >0.05). Conclusion Try not prove that improve ceftriaxone sodium sensitive liquid concentration can reduce the incidence of skin test false negative results caused by an al ergic reaction.

  17. Quantum chemical investigations aimed at modeling highly efficient zinc porphyrin dye sensitized solar cells.

    Science.gov (United States)

    Irfan, Ahmad; Hina, Naz; Al-Sehemi, Abdullah G; Asiri, Abdullah M

    2012-09-01

    Zinc tetraphenylporphyrin (ZnTPP) was modified by a push-pull strategy and then density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed for the resulting derivatives. The smallest HOMO-LUMO energy gaps were found in ZnTPP-6 and ZnTPP-7, which had nitro substituents and a conjugated chain, while the largest was observed for ZnTPP-5. The energy gaps of all of the systems designed in this work were smaller than that of ZnTPP. Clear intramolecular charge transfer was observed from donor to acceptor in ZnTPP-6 and ZnTPP-7, which had nitro groups at positions R8, R9, and R10, as well as in ZnTPP-3 and ZnTPP-4, which had cyano groups at those positions. The narrow band gaps (compared to that of ZnTPP) of these designed systems, where the LUMO is above the conduction band of TiO(2) and the HOMO is below the redox couple, indicate that they are efficient sensitizers. The B bands of these newly designed derivatives, except for ZnTPP-5, are redshifted compared with the B band of ZnTPP.

  18. Sensitivity of Biomarkers to Changes in Chemical Emissions in the Earth's Proterozoic Atmosphere

    CERN Document Server

    Grenfell, John Lee; von Paris, Philip; Godolt, Mareike; Hedelt, Pascal; Patzer, Beate; Stracke, Barbara; Rauer, Heike

    2010-01-01

    The search for life beyond the Solar System is a major activity in exoplanet science. However, even if an Earth-like planet were to be found, it is unlikely to be at a similar stage of evolution as the modern Earth. It is therefore of interest to investigate the sensitivity of biomarker signals for life as we know it for an Earth-like planet but at earlier stages of evolution. Here, we assess biomarkers i.e. species almost exclusively associated with life, in present-day and in 10% present atmospheric level oxygen atmospheres corresponding to the Earth's Proterozoic period. We investigate the impact of proposed enhanced microbial emissions of the biomarker nitrous oxide, which photolyses to form nitrogen oxides which can destroy the biomarker ozone. A major result of our work is regardless of the microbial activity producing nitrous oxide in the early anoxic ocean, a certain minimum ozone column can be expected to persist in Proterozoic-type atmospheres due to a stabilising feedback loop between ozone, nitrou...

  19. Critical Chemical-Mechanical Couplings that Define Permeability Modifications in Pressure-Sensitive Rock Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Derek Elsworth; Abraham Grader; Susan Brantley

    2007-04-25

    This work examined and quantified processes controlling changes in the transport characteristics of natural fractures, subjected to coupled thermal-mechanical-chemical (TMC) effects. Specifically, it examined the effects of mineral dissolution and precipitation mediated by mechanical effects, using laboratory through-flow experiments concurrently imaged by X-ray CT. These were conducted on natural and artificial fractures in cores using water as the permeant. Fluid and mineral mass balances are recorded and are correlated with in-sample saturation, porosity and fracture aperture maps, acquired in real-time by X-ray CT-imaging at a maximum spatial resolution of 15-50 microns per pixel. Post-test, the samples were resin-impregnated, thin-sectioned, and examined by microscopy to define the characteristics of dissolution and precipitation. The test-concurrent X-ray imaging, mass balances, and measurements of permeability, together with the post-test microscopy, were used to define dissolution/precipitation processes, and to constrain process-based models. These models define and quantify key processes of pressure solution, free-face dissolution, and shear-dilation, and the influence of temperature, stress level, and chemistry on the rate of dissolution, its distribution in space and time, and its influence on the mechanical and transport properties of the fracture.

  20. CHARACTERIZATION OF XANTHOMONAS AXONOPODIS PV. PUNICAE ISOLATES FROM WESTERN MAHARASHTRA AND THEIR SENSITIVITY TO CHEMICAL TREATMENTS

    Directory of Open Access Journals (Sweden)

    K. S. RAGHUWANSHI

    2013-01-01

    Full Text Available Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae is a major biotic constraint inpeninsular India. Field survey was undertaken in the major pomegranate growing regions of Western Maharashtra,which revealed the high prevalence of bacterial blight incidence in Solapur, Sangli and Nashik districts. Fourdifferent isolates of this pathogen were obtained from the highly infected plant materials collected during the fieldsurvey. X. axonopodis pv. punicae was detected from infected plant material and its identity was confirmed bymorphological, physiological, hypersensitive and pathogenicity tests. Nashik isolate was most virulent. On InterSimple Sequence Repeat (ISSR analysis they formed separate clusters with Akkalkot-Solapur isolate being mostdivergent, while Deola-Nashik and Sangamner-Ahmednagar isolates were most similar. Six chemical treatmentsshowed complete control under in vitro conditions while rest varied in their response to isolates. Completecontrol in all four isolates was observed with Bordeaux mixture (1%; captan (0.25% + Copper oxychloride(0.3%, captan (0.25% + copper hydroxide (0.3%, bromopol (500 ppm + copper oxychloride (0.3%,streptocycline (250 ppm + copper hydroxide (0.3%, streptocycline (500 ppm + copper hydroxide (0.3%during in vitro study

  1. Variable Temperature Stress in the Nematode Caenorhabditis elegans (Maupas) and Its Implications for Sensitivity to an Additional Chemical Stressor.

    Science.gov (United States)

    Cedergreen, Nina; Nørhave, Nils Jakob; Svendsen, Claus; Spurgeon, David J

    2016-01-01

    A wealth of studies has investigated how chemical sensitivity is affected by temperature, however, almost always under different constant rather than more realistic fluctuating regimes. Here we compared how the nematode Caenorhabditis elegans responds to copper at constant temperatures (8-24°C) and under fluctuation conditions of low (±4°C) and high (±8°C) amplitude (averages of 12, 16, 20°C and 16°C respectively). The DEBkiss model was used to interpret effects on energy budgets. Increasing constant temperature from 12-24°C reduced time to first egg, life-span and population growth rates consistent with temperature driven metabolic rate change. Responses at 8°C did not, however, accord with this pattern (including a deviation from the Temperature Size Rule), identifying a cold stress effect. High amplitude variation and low amplitude variation around a mean temperature of 12°C impacted reproduction and body size compared to nematodes kept at the matching average constant temperatures. Copper exposure affected reproduction, body size and life-span and consequently population growth. Sensitivity to copper (EC50 values), was similar at intermediate temperatures (12, 16, 20°C) and higher at 24°C and especially the innately stressful 8°C condition. Temperature variation did not increase copper sensitivity. Indeed under variable conditions including time at the stressful 8°C condition, sensitivity was reduced. DEBkiss identified increased maintenance costs and increased assimilation as possible mechanisms for cold and higher copper concentration effects. Model analysis of combined variable temperature effects, however, demonstrated no additional joint stressor response. Hence, concerns that exposure to temperature fluctuations may sensitise species to co-stressor effects seem unfounded in this case. PMID:26784453

  2. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  3. Study of surfactant-skin interactions by skin impedance measurements.

    Science.gov (United States)

    Lu, Guojin; Moore, David J

    2012-02-01

    The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation. PMID:21923733

  4. Study of surfactant-skin interactions by skin impedance measurements.

    Science.gov (United States)

    Lu, Guojin; Moore, David J

    2012-02-01

    The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation.

  5. Sagging Skin

    Science.gov (United States)

    ... turkey neck,” this occurs as skin loses its elasticity and in cases where individuals have lost a ... technique or procedure is appropriate for my skin type? Did the doctor show me before-and-after ...

  6. Skin Dictionary

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases Cosmetic treatments Dry / sweaty skin Eczema / dermatitis Hair and scalp ...

  7. Skin Biopsy

    Science.gov (United States)

    ... skin condition cannot be diagnosed by the patient's history and what the physician finds on examination alone. Confirming a clinical diagnosis may also be necessary prior to starting therapy. Skin biopsy types are as follows: Shave biopsies Punch biopsies ...

  8. Skin tears.

    Science.gov (United States)

    Baranoski, S

    2001-08-01

    Skin tears are a serious, painful problem for older patients. Find out how your staff can recognize patients at risk, what they can do to prevent skin tears, and how to manage them effectively if they occur.

  9. Skin Cancer

    Science.gov (United States)

    Skin cancer is the most common form of cancer in the United States. The two most common types ... face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common. Anyone ...

  10. Real-time, sensitive electrical detection of Cryptosporidium parvum oocysts based on chemical vapor deposition-grown graphene

    Science.gov (United States)

    It Wong, Jen; Wang, Lu; Shi, Yumeng; Palacios, Tomás; Kong, Jing; Dong, Xiaochen; Ying Yang, Hui

    2014-02-01

    Cryptosporidium parvum is a common intestinal parasitic protozoan that causes gastroenteritis in man and animals. It poses high risks to drinking water supply because of its ubiquitous distribution in water and their oocysts are resistant to harsh environment conditions. In this work, we demonstrated the use of large-size chemical vapor deposition (CVD) grown graphene films configured as field-effect device for rapid electrical detection of Cryptosporidium parvum oocysts (Cp. oocysts). The presence of Cp. oocysts causes the change in the transport characteristics of the antibody-functionalized graphene device, which can be measured in terms of the dependence of the drain current on the sweep of the gate voltage or the real-time drain current data under a constant gate voltage. The high sensor sensitivity of 25 oocysts per milliliter solution and good specificity were evaluated, indicating it a promising candidate for detecting waterborne pathogens in water quality control.

  11. Sensitivity Amplification in the Phosphorylation-Dephosphorylation Cycle: Nonequilibrium steady states, chemical master equation and temporal cooperativity

    CERN Document Server

    Ge, Hao

    2009-01-01

    A new type of cooperativity termed temporal cooperativity [Biophys. Chem. 105 585-593 (2003), Annu. Rev. Phys. Chem. 58 113-142 (2007)], emerges in the signal transduction module of phosphorylation-dephosphorylation cycle (PdPC). It utilizes multiple kinetic cycles in time, in contrast to allosteric cooperativity that utilizes multiple subunits in a protein. In the present paper, we thoroughly investigate both the deterministic (microscopic) and stochastic (mesoscopic) models, and focus on the identification of the source of temporal cooperativity via comparing with allosteric cooperativity. A thermodynamic analysis confirms again the claim that the chemical equilibrium state exists if and only if the phosphorylation potential $\\triangle G=0$, in which case the amplification of sensitivity is completely abolished. Then we provide comprehensive theoretical and numerical analysis with the first-order and zero-order assumptions in phosphorylation-dephosphorylation cycle respectively. Furthermore, it is interesti...

  12. Perspectives on Non-Animal Alternatives for Assessing Sensitization Potential in Allergic Contact Dermatitis

    OpenAIRE

    Sharma, Nripen S.; Jindal, Rohit; Mitra, Bhaskar; Lee, Serom; Li, Lulu; MAGUIRE, TIM J.; Schloss, Rene; Yarmush, Martin L.

    2012-01-01

    Skin sensitization remains a major environmental and occupational health hazard. Animal models have been used as the gold standard method of choice for estimating chemical sensitization potential. However, a growing international drive and consensus for minimizing animal usage have prompted the development of in vitro methods to assess chemical sensitivity. In this paper, we examine existing approaches including in silico models, cell and tissue based assays for distinguishing between sensiti...

  13. SKIN CANCER

    OpenAIRE

    Made Putri Hendaria; AAGN Asmarajaya; Sri Maliawan

    2013-01-01

    Skin is an organ which protect the human body from the environment. It was build by milion cells. According to the changes in human lifestyle which tends to unhealthy life, increasing ultraviolet radiation, toxins, and genetics makes the cells who build the skin do the abnormal growth being cancer cells. Classification of skin cancer is according the most common three types, they are Basal Cell Carcinoma, Squamous Cell Carcinoma, and Malignant Melanoma. More than 3,5 milion skin cancer cases ...

  14. A sensitive and environmentally friendly method for determination of chemical oxygen demand using NiCu alloy electrode

    International Nuclear Information System (INIS)

    Highlights: ► NiCu alloy modified electrode is used to determine chemical oxygen demand. ► NiCu alloy can effectively oxidize a wide range of organic compounds. ► Compared with the existing methods, this method has wide linear range and high sensitivity. ► The results are linearly correlated to those by the classic dichromate method. ► The proposed method has an excellent practical perspective in water quality control. - Abstract: A simple, sensitive and environmentally friendly method was developed for determination of chemical oxygen demand (COD) by cyclic voltammetry using nickel–copper (NiCu) alloy electrode. The structure and the electrochemical behavior of NiCu alloy electrode were investigated by atomic force microscope, energy dispersive X-ray spectrometer, and cyclic voltammetry, respectively. The results indicated that NiCu alloy film with high quality was stably modified on the surface of glass carbon (GC) electrode, which could effectively oxidize a wide range of organic compounds. Subsequently, the parameters affecting the analytical performance were investigated, including pH, dissolved oxygen and concentration of chloride ion. Under optimized conditions, the linear range was 10–1533 mg L−1 and the detection limit was 1.0 mg L−1. The results obtained from the proposed method were linearly correlated to those by the classic dichromate method (r = 0.9978, p < 0.01, n = 13). Finally, the validated method was used to determine the COD values of surface water, reclaimed water and wastewater. It was shown that the proposed method had an excellent practical perspective on determination of COD in water quality control and pollution evaluation.

  15. Chemical sensing employingpH sensitive emeraldine base thin film for carbon dioxide detection

    Science.gov (United States)

    Irimia-Vladu, Mihai

    impedance spectroscopy measurements, revealed valuable information about conduction mechanisms at pH levels were the overall conductivity of the film remained unchanged. Typical impedance spectra for the emeraldine thin films for a frequency sweep between 3.2 E7 to 1 Hz shows a single semicircle. The overall conductivity of the film (5x10-4 S/cm) does not change when CO 2 is bubbled through the water in which the sensor is immersed, but an additional semicircle starts to appear at low (less than 200 Hz) frequency corresponding to lowering the pH of the solution below 5.0. The original semicircle diminishes in size but maintains its initial peak frequency. The EB film is very sensitive to pH changes, therefore an additional semicircle appears in unpurified argon gas due to the reduction of the pH of water solution to 4.65. The same mechanism is displayed in hydrochloric acid solutions of various pH. The formation of the second semicircle depends on the initial conductivity of the emeraldine base film, a film displaying an initial conductivity of 4.8 x 10-3 S/cm forming the second semicircle at a pH of 5.85. The appearance of the second semicircle is most likely due to a preferential protonation in the insulating matrix of the polymer film. The overall conductivity of the film increases when the level of protonation in the insulating portion of the film reached a level close to the protonation level in the scattered metallic islands, allowing the electron-hopping mechanism to became active. The sensor output is stable and reproducible even after 11 months passed from the polymer film deposition.

  16. Skin Aging

    Science.gov (United States)

    Your skin changes as you age. You might notice wrinkles, age spots and dryness. Your skin also becomes thinner and loses fat, making it ... heal, too. Sunlight is a major cause of skin aging. You can protect yourself by staying out ...

  17. Chemical reconstruction of skin scars therapy using 100% trichloroacetic acid in the treatment of atrophic facial post varicella scars: A pilot study

    Directory of Open Access Journals (Sweden)

    Nidheesh Agarwal

    2013-01-01

    Full Text Available Context: Chickenpox (varicella is a common viral disease caused by Varicella zoster virus. Facial atrophic scars after varicella infection are not uncommon and pose a cosmetic problem. Like atrophic scars of other aetiologies, they are a difficult condition to treat. There are not enough references in the literature regarding efficient treatment of post varicella scars. High strength Trichloroacetic acid (TCA, which is known to cause dermal collagen remodelling, was used to treat varicella scars in the present study. Aims: The study was undertaken to assess the efficiency of Chemical Reconstruction of Skin Scars (CROSS technique using 100% TCA in the treatment of atrophic facial post varicella scars. Settings and Design: Open label, pilot study. Materials and Methods: A total of 16 patients with atrophic facial post varicella scars were treated by focal application of 100% TCA solution by pressing down upon the scar surface by a toothpick (CROSS technique. Total 4 sittings were given at 2 weekly intervals and the results evaluated after 3 months of follow-up. Statistical analysis was carried out using Fischer′s exact t-test. Results: All of the 13 patients who completed the study showed good clinical improvement, with 69% patients grading the response as excellent (>75% improvement, whereas the rest 31% patients reporting good (51-75% improvement. No significant complications were seen in any patient. Conclusions: CROSS technique using 100% TCA is a safe, cheap and effective therapy for the treatment of post varicella scars.

  18. 导入透明质酸猪脱细胞真皮基质的刺激性及致敏性研究%Skin irritation and sensitization of swine acellular dermal matrix treated with hyaluronic acid

    Institute of Scientific and Technical Information of China (English)

    宁少南; 赵筱卓; 王慧英; 张国安

    2012-01-01

    Objective To evaluate the skin irritation and sensitization potential of the swine acellular dermal matrix treated with hyaluronic acid (SADM-HA).Methods (1) Skin irritation test.Twelve New Zealand rabbits were divided into SADM-HA group,allogeneic skin group,and (human) xeno-skin group according to the random number table,with 4 rabbits in each group.Four test sites were designed on the back of each rabbit.Two test sites of each rabbit in the three groups were covered with SADM-HA,allogeneic skin,and xeno-skin,respectively.Another test site was covered with gauze containing 200 g/L sodium dodecyl sulfate solution as positive control.The last test site was covered with gauze containing normal saline as negative control.The primary irritation index and cumulative irritation index of each material were calculated.(2) Skin closed-patch test.Sixty guinea pigs were used.Fifty-four guinea pigs were divided into SADM-HA group,allogeneic skin group,and (human) xeno-skin group according to the random number table,with 18 guinea pigs in each group.Twelve guinea pigs in each of the three groups were correspondingly induced and stimulated by SADM-HA,allogeneic skin,and xeno-skin,with 6 guinea pigs in each group treated with ethanol-soaked gauze to serve as negative control.The remaining 6 guinea pigs were treated with gauze containing 25% α-hexylcinnamaldehyde ethanol solution as positive control.The rating scales of Magnusson and Kligman were used to grade the condition of skin after being treated with above-mentioned materials to evaluate skin sensitivity to them at post stimulation hour 24 and 48.Data were processed with the nonparametric test of independent samples.Results (1) In the skin irritation test,the primary irritation indexes of the three dressings in SADM-HA group,allogeneic skin group,and xeno-skin group were respectively-0.04,0.13,and 0.08.The cumulative irritation indexes of the three dressings in SADM-HA group,allogeneic skin group,and xeno-skin group were

  19. Dry transfer of chemical-vapor-deposition-grown graphene onto liquid-sensitive surfaces for tunnel junction applications

    Science.gov (United States)

    Feng, Ying; Chen, Ke

    2015-01-01

    We report a dry transfer method that can tranfer chemical vapor deposition (CVD) grown graphene onto liquid-sensitive surfaces. The graphene grown on copper (Cu) foil substrate was first transferred onto a freestanding 4 μm thick sputtered Cu film using the conventional wet transfer process, followed by a dry transfer process onto the target surface using a polydimethylsiloxane stamp. The dry-transferred graphene has similar properties to traditional wet-transferred graphene, characterized by scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and electrical transport measurements. It has a sheet resistance of 1.6 ˜ 3.4 kΩ/□, hole density of (4.1 ˜ 5.3) × 1012 cm-2, and hole mobility of 460 ˜ 760 cm2 V-1 s-1 without doping at room temperature. The results suggest that large-scale CVD-grown graphene can be transferred with good quality and without contaminating the target surface by any liquid. Mg/MgO/graphene tunnel junctions were fabricated using this transfer method. The junctions show good tunneling characteristics, which demonstrates the transfer technique can also be used to fabricate graphene devices on liquid-sensitive surfaces.

  20. Dry transfer of chemical-vapor-deposition-grown graphene onto liquid-sensitive surfaces for tunnel junction applications

    International Nuclear Information System (INIS)

    We report a dry transfer method that can tranfer chemical vapor deposition (CVD) grown graphene onto liquid-sensitive surfaces. The graphene grown on copper (Cu) foil substrate was first transferred onto a freestanding 4 μm thick sputtered Cu film using the conventional wet transfer process, followed by a dry transfer process onto the target surface using a polydimethylsiloxane stamp. The dry-transferred graphene has similar properties to traditional wet-transferred graphene, characterized by scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and electrical transport measurements. It has a sheet resistance of 1.6 ∼ 3.4 kΩ/□, hole density of (4.1 ∼ 5.3) × 1012 cm−2, and hole mobility of 460 ∼ 760 cm2 V−1 s−1 without doping at room temperature. The results suggest that large-scale CVD-grown graphene can be transferred with good quality and without contaminating the target surface by any liquid. Mg/MgO/graphene tunnel junctions were fabricated using this transfer method. The junctions show good tunneling characteristics, which demonstrates the transfer technique can also be used to fabricate graphene devices on liquid-sensitive surfaces. (paper)

  1. The implications of non-linear biological oscillations on human electrophysiology for electrohypersensitivity (EHS) and multiple chemical sensitivity (MCS).

    Science.gov (United States)

    Sage, Cindy

    2015-01-01

    maintenance; and resilience can be compromised. Electrohypersensitivity can be caused by successive assaults on human bioelectrochemical dynamics from exogenous electromagnetic fields (EMF) and RFR or a single acute exposure. Once sensitized, further exposures are widely reported to cause reactivity to lower and lower intensities of EMF/RFR, at which point thousand-fold lower levels can cause adverse health impacts to the electrosensitive person. Electrohypersensitivity (EHS) can be a precursor to, or linked with, multiple chemical sensitivity (MCS) based on reports of individuals who first develop one condition, then rapidly develop the other. Similarity of chemical biomarkers is seen in both conditions [histamines, markers of oxidative stress, auto-antibodies, heat shock protein (HSP), melatonin markers and leakage of the blood-brain barrier]. Low intensity pulsed microwave activation of voltage-gated calcium channels (VGCCs) is postulated as a mechanism of action for non-thermal health effects.

  2. 漆树叶皮肤刺激性与致敏性的实验研究%Experimental study on skin irritation and sensitization of Toxicodendron vernicifluum leaf

    Institute of Scientific and Technical Information of China (English)

    谢立璟; 张丽霞; 周静; 孙承业

    2011-01-01

    room temperature; the ratio of the leaf to distilled water was 1 to 1. Skin irritation testing was conducted in 6 New Zealand white rabbits. A patch ( 3 cm × 3 cm) of fur of each rabbit was shaved from both sides of its back. The paste 1.0 g was applied to the bare skin on the left side of the back and maintained for 4 hours and then cleaned off. Distilled water 0.5 ml was applied to the bare skin on the right side of the back as control. Skin responses in the part applied with the paste were observed and scored 1, 24, 48 and 72 hours after cleaning. Skin sensitization testing was conducted in 50 albino guinea pigs. These pigs were divided into 3 groups: the experiment group (10 males and 10 females), the positive control group (10 males and 10 females) and the negative control group (S males and S females). A patch (2 cm ×2 cm) of fur of each pig was shaved from both sides of its back. On the beginning of experiment and on days 7 and 14 of experiment, the paste 0. 8 g, 2. 5% 2,4-dinitro-chlorobenzene 0.2 g and distilled water 0.4 ml were applied to the bare skin on the left side of each pig's back in the experiment, positive control and negative control groups and maintained for 6 hours and then cleaned off, respectively. On days 28 of experiment, the paste 0. 8 g was applied to the bare skin on the left side of each pig's back in the experiment and negative control groups, 1.0% 2, 4-dinitro-chlorobenzene 0. 2 g was applied to the bare skin on the left side of each pig' s back in the positive control group and maintained for 6 hours and then cleaned. The rate and severity of sensitization were calculated and assessed 24 and 48 hours after cleaning, respectively. Results; In the skin irritation testing, 3 rabbits developed erythema after applying the paste to their skin. The average irritation score was 0.67 and the irritation severity was mild. In the skin sensitization testing, the guinea pigs in the experiment and negative control groups did not develop erythema

  3. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  4. The direct peptide reactivity assay: selectivity of chemical respiratory allergens.

    Science.gov (United States)

    Lalko, Jon F; Kimber, Ian; Gerberick, G Frank; Foertsch, Leslie M; Api, Anne Marie; Dearman, Rebecca J

    2012-10-01

    It is well known that some chemicals are capable of causing allergic diseases of the skin and respiratory tract. Commonly, though not exclusively, chemical allergens are associated with the selective development of skin or respiratory sensitization. The reason for this divergence is unclear, although it is hypothesized that the nature of interactions between the chemical hapten and proteins is influential. The direct peptide reactivity assay (DPRA) has been developed as a screen for the identification of skin-sensitizing chemicals, and here we describe the use of this method to explore whether differences exist between skin and respiratory allergens with respect to their peptide-binding properties. Known skin and respiratory sensitizers were reacted with synthetic peptides containing either lysine (Lys) or cysteine (Cys) for 24 h. The samples were analyzed by HPLC/UV, and the loss of peptide from the reaction mixture was expressed as the percent depletion compared with the control. The potential for preferential reactivity was evaluated by comparing the ratio of Lys to Cys depletion (Lys:Cys ratio). The results demonstrate that the majority of respiratory allergens are reactive in the DPRA, and that in contrast to most skin-sensitizing chemicals, preferentially react with the Lys peptide. These data suggest that skin and respiratory chemical allergens can result in different protein conjugates, which may in turn influence the quality of induced immune responses. Overall, these investigations reveal that the DPRA has considerable potential to be incorporated into tiered testing approaches for the identification and characterization of chemical respiratory allergens. PMID:22713598

  5. The feasibility of a sensitive low-dose method for the in vivo evaluation of Fe in skin using K-shell x-ray fluorescence (XRF)

    Science.gov (United States)

    Farquharson, Michael J.; Bradley, David A.

    1999-04-01

    An x-ray fluorescence (XRF) system designed for monitoring of skin Fe concentrations has been performance tested for use on patients treated for -thalassaemia. The essentials of the system are: a collimated x-ray tube operated at 20 kV and 20 mA; energy selection of the x-ray beam by means of a Cu K-edge filter; use of skin phantoms containing concentrations of Fe in the range 10 to 100 parts per million (ppm); and a high-purity germanium detector placed at to the incident beam. For a Cu K-edge filter of 0.15 mm thickness a quasi-monoenergetic beam of approximately 8.4 keV is obtained which is close to the absorption edge of Fe (7.11 keV). For a real-time counting period of 400 s the system is capable of detecting Fe concentrations of ppm at a skin dose of the order of 5 mSv. This level of Fe is at the higher end of the normal range found in the skin. In using the same system and operating parameters, measurements on a sample of ferritin obtained from a rat's liver yield an Fe concentration of ppm for a measurement time of 500 s; this can be compared with suppliers' data indicating an Fe level of 36 ppm.

  6. Sensitization to cereals and peanut evidenced by skin prick test and specific IgE in food-tolerant, grass pollen allergic patients

    DEFF Research Database (Denmark)

    Martens, Maria; Schnoor, Heidi J; Malling, Hans-Jørgen;

    2011-01-01

    The botanical relation between grass and cereal grains may be relevant when diagnosing food allergy to cereals. The aim was to investigate the diagnostic specificity of skin prick test (SPT) and specific immunoglobulin E (sIgE) tests to cereals and peanut in grass pollen allergic subjects without...

  7. Thermodynamic Insights and Conceptual Design of Skin-Sensitive Chitosan Coated Ceramide/PLGA Nanodrug for Regeneration of Stratum Corneum on Atopic Dermatitis

    Science.gov (United States)

    Jung, Sang-Myung; Yoon, Gwang Heum; Lee, Hoo Chul; Jung, Moon Hee; Yu, Sun Il; Yeon, Seung Ju; Min, Seul Ki; Kwon, Yeo Seon; Hwang, Jin Ha; Shin, Hwa Sung

    2015-01-01

    Atopic dermatitis (AD) is a complex skin disease primarily characterized by psoriasis of the stratum corneum. AD drugs have usually been used in acidic and hydrophilic solvents to supply moisture and prevent lipid defects. Ceramide is a typical treatment agent to regenerate the stratum corneum and relieve symptoms of AD. However, ceramide has limitation on direct use for skin because of its low dispersion properties in hydrophilic phase and side effects at excessive treatment. In this study, ceramide imbedded PLGA nanoparticles were developed with chitosan coating (Chi-PLGA/Cer) to overcome this problem. The chitosan coating enhanced initial adherence to the skin and prevented the initial burst of ceramide, but was degraded by the weakly acidic nature of skin, resulting in controlled release of ceramide with additional driving force of the squeezed PLGA nanoparticles. Additionally, the coating kinetics of chitosan were controlled by manipulating the reaction conditions and then mathematically modeled. The Chi-PLGA/Cer was not found to be cytotoxic and ceramide release was controlled by pH, temperature, and chitosan coating. Finally, Chi-PLGA/Cer was demonstrated to be effective at stratum corneum regeneration in a rat AD model. Overall, the results presented herein indicated that Chi-PLGA/Cer is a novel nanodrug for treatment of AD. PMID:26666701

  8. Occupational skin cancers

    Energy Technology Data Exchange (ETDEWEB)

    Gawkrodger, D.J. [Royal Hallamshire Hospital, Sheffield (United Kingdom). Dept. of Dermatology

    2004-10-01

    Skin cancer due to occupation is more common than is generally recognized, although it is difficult to obtain an accurate estimate of its prevalence. Over the past two centuries, occupational skin cancers have particularly been due to industrial exposure of men (it seems more so than women) to chemical carcinogens such as polycyclic hydrocarbons (e.g. from coal tar products) or to arsenic. Industrial processes have improved in most Western countries to limit this type of exposure, but those with outdoor occupations are still exposed to solar ultraviolet irradiation without this being widely recognized as an industrial hazard. Ionizing radiation such as X-rays can also cause skin cancer. Occupational skin cancers often resemble skin tumours found in non-occupational subjects, e.g. basal cell carcinoma, squamous cell carcinoma and malignant melanoma, but some pre-malignant lesions can be more specific and point to an occupational origin, e.g. tar keratoses or arsenical keratoses. An uncommon but well-recognized cause of occupational skin cancer is that which results from scar formation following an industrial burn. In the future it will be necessary to focus on preventative measures, e.g. for outdoor workers, the need to cover up in the sun and use sun protective creams and a campaign for earlier recognition of skin cancers, which are usually curable if treated in their early stages.

  9. Effect of detergents on the physico-chemical properties of skin stratum corneum: A two-photon excitation fluorescence microscopy study

    DEFF Research Database (Denmark)

    Bloksgaard, Maria; Brewer, Jonathan R.; Pashkovski, Eugene;

    2014-01-01

    OBJECTIVE: Understanding the structural and dynamical features of skin is critical for advancing innovation in personal care and drug discovery. Synthetic detergent mixtures used in commercially available body wash products are thought to be less aggressive towards the skin barrier when compared ...

  10. Skin Diseases: Skin Health and Skin Diseases

    Science.gov (United States)

    ... Usually the cause is staphylococcal (staph), but sometimes streptococcus (strep) can cause it, too. It is most ... color or outline, or in any other way. Psoriasis © 2008 Logical Images, Inc. Psoriasis —A skin disease ...

  11. SKIN KINETICS AND DERMAL CLEARANCE

    Directory of Open Access Journals (Sweden)

    Prakash Shashi

    2012-08-01

    Full Text Available Availability of several therapeutic and cosmetic formulations for topical application has made the research on skin kinetics as a topic of current interest. Topical formulations are typically meant for local effect although there is always a chance that the low molecular weight chemicals are easily transported across the skin layer and make it available in the systemic circulation. Thus there is a major concern about the transport of chemical moieties following the topical application of cosmetics and therapeutic formulations and the real time measurement of the molecules in the skin layer has become obligatory. It is well known that the properties of both drug and the excipients have identical role in determining the skin permeability of chemical moieties. In the last decade several investigations have been carried out in this filed using several in vitro and in vivo models. This review provides a brief account on the basics of skin kinetics, parameters assessed, various techniques and methods adapted in skin kinetic studies. Moreover, we have also discussed about the micro-environment inside the skin layer and the possible mechanism of drug depot formation, skin metabolism and clearance of molecules from the skin layers.

  12. Mindfulness-based cognitive therapy for multiple chemical sensitivity: a study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Hauge Christian Riise

    2012-09-01

    Full Text Available Abstract Background Multiple chemical sensitivity (MCS is a condition characterized by recurrent, self-reported symptoms from multiple organ systems, attributable to exposure to a wide range of chemically unrelated substances at low levels. The pathophysiology is unknown, and affected individuals generally favor avoidance of the symptom triggering substances as a coping strategy. The impact of MCS on daily life may thus be severe. An intervention that may effectively reduce the impact of MCS, alleviate the symptoms and the psychological distress associated with the condition is therefore highly needed. In this study we will assess the effects of a mindfulness-based cognitive (MBCT program on MCS. Methods/Design Using a randomized controlled design (RCT, we will compare MBCT with treatment as usual (TAU. The MBCT intervention will include 8 weekly 2.5 hour sessions, and 45 minutes of mindfulness home practice 6 days each week. Participants will be asked to complete questionnaires at baseline, post-treatment, and at 6 and 12 months’ follow-up. Based on sample size estimation, 82 participants will be randomized to either the MBCT intervention or to TAU. The primary outcome will be a measure of the impact of MCS on the participants’ lives. The secondary outcome measures are physical symptoms of psychological distress, perceived stress, illness perceptions, QOL, and work ability. Lastly, we will assess whether any effect of MBCT on the primary effect measure is mediated by level of mindfulness, self-compassion, perceived stress, and rumination. Discussion This trial will provide important information on the effects of MBCT on MCS. Trials registration Clinical trials identifier NCT01240395

  13. Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 2: Base Case and Sensitivity Analysis

    KAUST Repository

    Zhao, Zhenlong

    2013-01-17

    Part 1 (10.1021/ef3014103) of this series describes a new rotary reactor for gas-fueled chemical-looping combustion (CLC), in which, a solid wheel with microchannels rotates between the reducing and oxidizing streams. The oxygen carrier (OC) coated on the surfaces of the channels periodically adsorbs oxygen from air and releases it to oxidize the fuel. A one-dimensional model is also developed in part 1 (10.1021/ef3014103). This paper presents the simulation results based on the base-case design parameters. The results indicate that both the fuel conversion efficiency and the carbon separation efficiency are close to unity. Because of the relatively low reduction rate of copper oxide, fuel conversion occurs gradually from the inlet to the exit. A total of 99.9% of the fuel is converted within 75% of the channel, leading to 25% redundant length near the exit, to ensure robustness. In the air sector, the OC is rapidly regenerated while consuming a large amount of oxygen from air. Velocity fluctuations are observed during the transition between sectors because of the complete reactions of OCs. The gas temperature increases monotonically from 823 to 1315 K, which is mainly determined by the solid temperature, whose variations with time are limited within 20 K. The overall energy in the solid phase is balanced between the reaction heat release, conduction, and convective cooling. In the sensitivity analysis, important input parameters are identified and varied around their base-case values. The resulting changes in the model-predicted performance revealed that the most important parameters are the reduction kinetics, the operating pressure, and the feed stream temperatures. © 2012 American Chemical Society.

  14. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System.

    Directory of Open Access Journals (Sweden)

    Jacek Panek

    Full Text Available Spoilage of heat processed food and beverage by heat resistant fungi (HRF is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700, the other from thermal processed strawberry product in 2012 (KC179765, used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods.

  15. 75 FR 22148 - Request for the Technical Review of 22 Draft Skin Notation Assignments and Skin Notation Profiles

    Science.gov (United States)

    2010-04-27

    ... Skin Notation Assignments and Skin Notation Profiles AGENCY: National Institute for Occupational Safety... public review of the draft skin notations and support technical documents entitled ``Skin Notations Profiles, for 22 chemicals.'' NIOSH is requesting technical reviews of the draft Skin Notation Profiles....

  16. Curious Skin

    OpenAIRE

    Angel, G.

    2010-01-01

    Some of Henry Wellcome’s collection of tattoos on human skin will be on display in our forthcoming Skin exhibition. But how did the Parisian doctor from whom they were acquired come by his macabre collection of tattoos in the first place, and what did they mean to those whose skin they were on? It’s Gemma Angel‘s job to find out…

  17. Contact sensitizer nickel sulfate activates the transcription factors NF-kB and AP-1 and increases the expression of nitric oxide synthase in a skin dendritic cell line

    OpenAIRE

    Cruz, MT; Gonçalo, Margarida; A. Figueiredo; Carvalho, AP; Duarte, CB

    2004-01-01

    Nuclear factor kappa B (NF-kB) and activating protein-1 (AP-1) transcription factors are ubiquitously expressed signaling molecules known to regulate the transcription of a large number of genes involved in immune responses, namely the inducible isoform of nitric oxide synthase (iNOS). In this study, we demonstrate that a fetal skin-derived dendritic cell line (FSDC) produces nitric oxide (NO) in response to the contact sensitizer nickel sulfate (NiSO(4)) and increases the expression of the i...

  18. Sensitive and fast response ethanol chemical sensor based on as-grown Gd2O3 nanostructures

    Institute of Scientific and Technical Information of China (English)

    MM Abdullah; Mohammed M Rahman; Houcine Bouzid; M Faisal; Sher Bahadar Khan; SA Al-Sayari; Adel A Ismail

    2015-01-01

    Well crystalline gadolinium oxide (Gd2O3) nanostructures were grown by annealing the hydrothermally as-prepared nanostructures without using any template. Microscopic studies of Gd2O3 nanostructures were recorded along the [111] direction due to the clearly resolved interplanar distance d(222)~0.31 nm of the cubic crystal structure Gd2O3. Sensing mechanism of Gd2O3 as efficient electron mediator for the detection of ethanol was explored. As-fabricated sensor demonstrated the high-sensitivity of~0.266 µAm/M/cm2 with low detection limit (~52.2 µmol/L) and correlation coefficient (r2, 0.618). To the best of our knowledge, this was the first report for the detection of ethanol using as-grown (at 1000 ºC) Gd2O3 nanostructures by simple and reliable I-V technique and rapid assessment of the reaction kinetics (in the order of seconds). The low cost of the starting reagents and the simplicity of the synthetic route made it a promising chemical sensor for the detection of various toxic analytes, which are not en-vironmentally safe.

  19. Cortical activity during olfactory stimulation in multiple chemical sensitivity: a {sup 18}F-FDG PET/CT study

    Energy Technology Data Exchange (ETDEWEB)

    Chiaravalloti, Agostino; Di Pietro, Barbara [University Tor Vergata, Department of Biomedicine and Prevention, Rome (Italy); Pagani, Marco [Institute of Cognitive Sciences and Technologies, CNR, Rome (Italy); Department of Nuclear Medicine Karolinska Hospital Stockholm, Stockholm (Sweden); Micarelli, Alessandro; Alessandrini, Marco [University Tor Vergata, Department of Medical Science and Translational Medicine, Rome (Italy); Genovesi, Giuseppe [University La Sapienza, Department of Experimental Medicine, Rome (Italy); University La Sapienza, Regional Center for Diagnosis, Treatment and Prevention of MCS, Rome (Italy); Schillaci, Orazio [University Tor Vergata, Department of Biomedicine and Prevention, Rome (Italy); IRCCS Neuromed, Pozzilli (Italy)

    2015-04-01

    To investigate the differences in brain glucose consumption during olfactory stimulation between subjects affected by multiple chemical sensitivity (MCS) and a group of healthy individuals. Two {sup 18}F-FDG PET/CT scans were performed in 26 subjects (6 men and 20 women; mean age 46.7 ± 11 years) with a clinical diagnosis of MCS and in 11 healthy controls (6 women and 5 men; mean age 45.7 ± 11 years), the first scan after a neutral olfactory stimulation (NS) and the second after a pure olfactory stimulation (OS). Differences in {sup 18}F-FDG uptake were analysed by statistical parametric mapping (SPM2). In controls OS led to an increase in glucose consumption in BA 18 and 19 and a reduction in glucose metabolism in BA 10, 11, 32 and 47. In MCS subjects, OS led to an increase in glucose consumption in BA 20, 23, 18 and 37 and a reduction in glucose metabolism in BA 8, 9 and 10. The results of our study suggest that cortical activity in subjects with MCS differs from that in healthy individuals during olfactory stimulation. (orig.)

  20. Sensitization to cereals and peanut evidenced by skin prick test and specific IgE in food-tolerant, grass pollen allergic patients

    OpenAIRE

    Martens Maria; Schnoor Heidi J; Malling Hans-Jørgen; Poulsen Lars K

    2011-01-01

    Abstract Background The botanical relation between grass and cereal grains may be relevant when diagnosing food allergy to cereals. The aim was to investigate the diagnostic specificity of skin prick test (SPT) and specific immunoglobulin E (sIgE) tests to cereals and peanut in grass pollen allergic subjects without history of, and clinically reactions to foods botanically related to grass. Methods 70 subjects (41 females; mean age 32 years) and 20 healthy controls (13 females; mean age 24 ye...

  1. [Studies on chemical protectors against radiation. XXVI. Protective effect of various extracts on crude drugs on skin injury induced by X-irradiation].

    Science.gov (United States)

    Sato, Y; Ohta, S; Sakurai, N; Shinoda, M

    1989-02-01

    The protective potency against skin injury on mice induced by X-irradiation was studied by use of 72 extracts of crude drugs. The protective potency was determined according to the degrees on skin injury after irradiation of 1100R, 30 k Vp soft X-ray. As a result of these study, 16 kinds of crude drugs such as Rosae Fructus, Aloe arborescens (Herba), Citri Leiocarpae Exocarpium, Schizonepetae Spica, Evodiae Fructus, Bupleuri Radix, Corni Fructus, Perillae Herba, Anemarrhenae Rhizoma, Menthae Herba, Trapae Fructus, Angelicae Dahuricae Radix, Sinomeni Caulis et Rhizoma, Ephedrae Herba, Acer nikoense (Cortex), Forsythiae Fructus, revealed protective potencies on skin injury. PMID:2746469

  2. SKIN KINETICS AND DERMAL CLEARANCE

    OpenAIRE

    Prakash Shashi; Nair Anroop; Saini Vipin; Sahu Neelam

    2012-01-01

    Availability of several therapeutic and cosmetic formulations for topical application has made the research on skin kinetics as a topic of current interest. Topical formulations are typically meant for local effect although there is always a chance that the low molecular weight chemicals are easily transported across the skin layer and make it available in the systemic circulation. Thus there is a major concern about the transport of chemical moieties following the topical application of cosm...

  3. Occupational dermal exposure to nanoparticles and nano-enabled products: Part I-Factors affecting skin absorption.

    Science.gov (United States)

    Larese Filon, Francesca; Bello, Dhimiter; Cherrie, John W; Sleeuwenhoek, Anne; Spaan, Suzanne; Brouwer, Derk H

    2016-08-01

    The paper reviews and critically assesses the evidence on the relevance of various skin uptake pathways for engineered nanoparticles, nano-objects, their agglomerates and aggregates (NOAA). It focuses especially in occupational settings, in the context of nanotoxicology, risk assessment, occupational medicine, medical/epidemiological surveillance efforts, and the development of relevant exposure assessment strategies. Skin uptake of nanoparticles is presented in the context of local and systemic health effects, especially contact dermatitis, skin barrier integrity, physico-chemical properties of NOAA, and predisposing risk factors, such as stratum corneum disruption due to occupational co-exposure to chemicals, and the presence of occupational skin diseases. Attention should be given to: (1) Metal NOAA, since the potential release of ions may induce local skin effects (e.g. irritation and contact dermatitis) and absorption of toxic or sensitizing metals; (2) NOAA with metal catalytic residue, since potential release of ions may also induce local skin effects and absorption of toxic metals; (3) rigid NOAA smaller than 45nm that can penetrate and permeate the skin; (4) non rigid or flexible NOAA, where due to their flexibility liposomes and micelles can penetrate and permeate the intact skin; (5) impaired skin condition of exposed workers. Furthermore, we outline possible situations where health surveillance could be appropriate where there is NOAA occupational skin exposures, e.g. when working with nanoparticles made of sensitizer metals, NOAA containing sensitizer impurities, and/or in occupations with a high prevalence of disrupted skin barrier integrity. The paper furthermore recommends a stepwise approach to evaluate risk related to NOAA to be applied in occupational exposure and risk assessment, and discusses implications related to health surveillance, labelling, and risk communication. PMID:27289581

  4. The development of a 3D immunocompetent model of human skin

    International Nuclear Information System (INIS)

    As the first line of defence, skin is regularly exposed to a variety of biological, physical and chemical insults. Therefore, determining the skin sensitization potential of new chemicals is of paramount importance from the safety assessment and regulatory point of view. Given the questionable biological relevance of animal models to human as well as ethical and regulatory pressure to limit or stop the use of animal models for safety testing, there is a need for developing simple yet physiologically relevant models of human skin. Herein, we describe the construction of a novel immunocompetent 3D human skin model comprising of dendritic cells co-cultured with keratinocytes and fibroblasts. This model culture system is simple to assemble with readily-available components and importantly, can be separated into its constitutive individual layers to allow further insight into cell–cell interactions and detailed studies of the mechanisms of skin sensitization. In this study, using non-degradable microfibre scaffolds and a cell-laden gel, we have engineered a multilayer 3D immunocompetent model comprised of keratinocytes and fibroblasts that are interspersed with dendritic cells. We have characterized this model using a combination of confocal microscopy, immuno-histochemistry and scanning electron microscopy and have shown differentiation of the epidermal layer and formation of an epidermal barrier. Crucially the immune cells in the model are able to migrate and remain responsive to stimulation with skin sensitizers even at low concentrations. We therefore suggest this new biologically relevant skin model will prove valuable in investigating the mechanisms of allergic contact dermatitis and other skin pathologies in human. Once fully optimized, this model can also be used as a platform for testing the allergenic potential of new chemicals and drug leads. (paper)

  5. In vitro micro-physiological immune-competent model of the human skin.

    Science.gov (United States)

    Ramadan, Qasem; Ting, Fiona Chia Wan

    2016-05-21

    Skin allergy, in particular, allergic contact dermatitis and irritant contact dermatitis, are common occupational and environmental health problems affecting the quality of life of a significant proportion of the world population. Since all new ingredients to be incorporated into a product are potential skin allergens, it is essential that these ingredients be first tested for their allergenic potential. However, despite the considerable effort using animal models to understand the underlying mechanism of skin sensitization, to date, the molecular and cellular responses due to skin contact with sensitizers are still not fully understood. To replace animal testing and to improve the prediction of skin sensitization, significant attention has been directed to the use of reconstructed organotypic in vitro models of human skin. Here we describe a miniaturized immune competent in vitro model of human skin based on 3D co-culture of immortalized human keratinocytes (HaCaT) as a model of the epidermis barrier and human leukemic monocyte lymphoma cell line (U937) as a model of human dendritic cells. The biological model was fitted in a microfluidic-based cell culture system that provides a dynamic cellular environment that mimics the in vivo environment of skin. The dynamic perfusion of culture media significantly improved the tight junction formation as evidenced by measuring higher values of TEER compared to static culture. This setting also maintained the high viability of cells over extended periods of time up to 17 days. The perfusion-based culture also allows growth of the cells at the air-liquid interface by exposing the apical side of the cells to air while providing the cell nutrients through a basolateral fluidic compartment. The microsystem has been evaluated to investigate the effect of the chemical and physical (UV irradiation) stimulation on the skin barrier (i.e. the TJ integrity). Three-tiered culture differential stimulation allowed the investigation of the

  6. Oily skin

    Science.gov (United States)

    ... keep your skin clean using warm water and soap, or a soapless cleanser. Clean your face with astringent pads if frequent face washing causes irritation. Use only water-based or oil-free cosmetics if you have oily skin. Your ...

  7. Chemically modified ion-sensitive field-effect transistors: elimination of the liquid juction potential in a double sensor flow-injection analysis cell

    NARCIS (Netherlands)

    Cobben, Peter L.H.M.; Egberink, Richard J.M.; Bomer, J.G.; Schouwenaar, Robert; Brzozka, Zbigniew; Bergveld, Piet; Reinhoudt, David N.; Bos, Martinus

    1993-01-01

    A flow-through cell was designed that can be used for flow-injection analysis with two chemically modified ion-sensitive field-effect transistors (CHEMFETs) in close proximity. This offers the possibility of a differential measurement without influence of the liquid junction potential. The different

  8. The future of skin metagenomics.

    Science.gov (United States)

    Mathieu, Alban; Vogel, Timothy M; Simonet, Pascal

    2014-01-01

    Metagenomics, the direct exploitation of environmental microbial DNA, is complementary to traditional culture-based approaches for deciphering taxonomic and functional microbial diversity in a plethora of ecosystems, including those related to the human body such as the mouth, saliva, teeth, gut or skin. DNA extracted from human skin analyzed by sequencing the PCR-amplified rrs gene has already revealed the taxonomic diversity of microbial communities colonizing the human skin ("skin microbiome"). Each individual possesses his/her own skin microbial community structure, with marked taxonomic differences between different parts of the body and temporal evolution depending on physical and chemical conditions (sweat, washing etc.). However, technical limitations due to the low bacterial density at the surface of the human skin or contamination by human DNA still has inhibited extended use of the metagenomic approach for investigating the skin microbiome at a functional level. These difficulties have been overcome in part by the new generation of sequencing platforms that now provide sequences describing the genes and functions carried out by skin bacteria. These methodological advances should help us understand the mechanisms by which these microorganisms adapt to the specific chemical composition of each skin and thereby lead to a better understanding of bacteria/human host interdependence. This knowledge will pave the way for more systemic and individualized pharmaceutical and cosmetic applications.

  9. Cobalt as chemical modifier to improve chromium sensitivity and minimize matrix effects in tungsten coil atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sidnei G. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil); Donati, George L., E-mail: georgedonati@yahoo.com.br [Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109 (United States); Santos, Luana N. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil); Jones, Bradley T. [Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109 (United States); Nóbrega, Joaquim A. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil)

    2013-05-30

    Graphical abstract: -- Highlights: •Charge transfer reactions increase the population of Cr{sup +}. •Chromium ions and electrons recombine to form excited-state Cr atoms. •A 10-fold improvement in LOD is observed for Cr emission measurements. •The two-step ionization/excitation mechanism improves sensitivity and accuracy. •High concentrations of Co also minimize matrix effects. -- Abstract: Cobalt is used as chemical modifier to improve sensitivity and minimize matrix effects in Cr determinations by tungsten coil atomic emission spectrometry (WCAES). The atomizer is a tungsten filament extracted from microscope light bulbs. A solid-state power supply and a handheld CCD-based spectrometer are also used in the instrumental setup. In the presence of 1000 mg L{sup −1} Co, WCAES limit of detection for Cr (λ = 425.4 nm) is calculated as 0.070 mg L{sup −1}; a 10-fold improvement compared to determinations without Co modifier. The mechanism involved in such signal enhancement is similar to the one observed in ICP OES and ICP-MS determinations of As and Se in the presence of C. Cobalt increases the population of Cr{sup +} by charge transfer reactions. In a second step, Cr{sup +}/e{sup −} recombination takes place, which results in a larger population of excited-state Cr atoms. This alternative excitation route is energetically more efficient than heat transfer from atomizer and gas phase to analyte atoms. A linear dynamic range of 0.25–10 mg L{sup −1} and repeatability of 3.8% (RSD, n = 10) for a 2.0 mg L{sup −1} Cr solution are obtained with this strategy. The modifier high concentration also contributes to improving accuracy due to a matrix-matching effect. The method was applied to a certified reference material of Dogfish Muscle (DORM-2) and no statistically significant difference was observed between determined and certified Cr values at a 95% confidence level. Spike experiments with bottled water samples resulted in recoveries between 93% and

  10. Reliable disease biomarkers characterizing and identifying electrohypersensitivity and multiple chemical sensitivity as two etiopathogenic aspects of a unique pathological disorder.

    Science.gov (United States)

    Belpomme, Dominique; Campagnac, Christine; Irigaray, Philippe

    2015-01-01

    Much of the controversy over the causes of electro-hypersensitivity (EHS) and multiple chemical sensitivity (MCS) lies in the absence of both recognized clinical criteria and objective biomarkers for widely accepted diagnosis. Since 2009, we have prospectively investigated, clinically and biologically, 1216 consecutive EHS and/or MCS-self reporting cases, in an attempt to answer both questions. We report here our preliminary data, based on 727 evaluable of 839 enrolled cases: 521 (71.6%) were diagnosed with EHS, 52 (7.2%) with MCS, and 154 (21.2%) with both EHS and MCS. Two out of three patients with EHS and/or MCS were female; mean age (years) was 47. As inflammation appears to be a key process resulting from electromagnetic field (EMF) and/or chemical effects on tissues, and histamine release is potentially a major mediator of inflammation, we systematically measured histamine in the blood of patients. Near 40% had a increase in histaminemia (especially when both conditions were present), indicating a chronic inflammatory response can be detected in these patients. Oxidative stress is part of inflammation and is a key contributor to damage and response. Nitrotyrosin, a marker of both peroxynitrite (ONOO°-) production and opening of the blood-brain barrier (BBB), was increased in 28% the cases. Protein S100B, another marker of BBB opening was increased in 15%. Circulating autoantibodies against O-myelin were detected in 23%, indicating EHS and MCS may be associated with autoimmune response. Confirming animal experiments showing the increase of Hsp27 and/or Hsp70 chaperone proteins under the influence of EMF, we found increased Hsp27 and/or Hsp70 in 33% of the patients. As most patients reported chronic insomnia and fatigue, we determined the 24 h urine 6-hydroxymelatonin sulfate (6-OHMS)/creatinin ratio and found it was decreased (<0.8) in all investigated cases. Finally, considering the self-reported symptoms of EHS and MCS, we serially measured the brain blood

  11. Sensitivity of thermal infrared nadir instruments to the chemical and microphysical properties of UTLS secondary sulfate aerosols

    Science.gov (United States)

    Sellitto, P.; Legras, B.

    2016-01-01

    Monitoring upper-tropospheric-lower-stratospheric (UTLS) secondary sulfate aerosols and their chemical and microphysical properties from satellite nadir observations is crucial to better understand their formation and evolution processes and then to estimate their impact on UTLS chemistry, and on regional and global radiative balance. Here we present a study aimed at the evaluation of the sensitivity of thermal infrared (TIR) satellite nadir observations to the chemical composition and the size distribution of idealised UTLS sulfate aerosol layers. The extinction properties of sulfuric acid/water droplets, for different sulfuric acid mixing ratios and temperatures, are systematically analysed. The extinction coefficients are derived by means of a Mie code, using refractive indices taken from the GEISA (Gestion et Étude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information) spectroscopic database and log-normal size distributions with different effective radii and number concentrations. IASI (Infrared Atmospheric Sounding Interferometer) pseudo-observations are generated using forward radiative transfer calculations performed with the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model, to estimate the impact of the extinction of idealised aerosol layers, at typical UTLS conditions, on the brightness temperature spectra observed by this satellite instrument. We found a marked and typical spectral signature of these aerosol layers between 700 and 1200 cm-1, due to the absorption bands of the sulfate and bisulfate ions and the undissociated sulfuric acid, with the main absorption peaks at 1170 and 905 cm-1. The dependence of the aerosol spectral signature to the sulfuric acid mixing ratio, and effective number concentration and radius, as well as the role of interfering parameters like the ozone, sulfur dioxide, carbon dioxide and ash absorption, and temperature and water vapour profile uncertainties

  12. Self-reported occupational exposure to chemical and physical factors and risk of skin problems: a 3-year follow-up study of the general working population of Norway.

    Science.gov (United States)

    Alfonso, Jose Hernan; Thyssen, Jacob P; Tynes, Tore; Mehlum, Ingrid Sivesind; Johannessen, Håkon A

    2015-11-01

    Prospective studies on occupational dermatoses in the general working population are sparse. This study investigated prospectively the impact of self-reported occupational exposure to chemicals and physical factors on the risk of skin problems. The cohort comprised respondents drawn randomly from the general population in Norway, who were registered employed in 2006 and 2009 (n = 6,745). Indoor dry air (odds ratio (OR) 1.3; 95% confidence interval (95% CI) 1.1-1.6) was a significant baseline predictor of skin problems at follow-up, whereas exposure to cleaning products (OR 1.7; 95% CI 1.2-2.5), water (OR 1.4; 95% CI 1.1-1.9) and indoor dry air (OR 1.6; 95% CI 1.1-2.1) at both measurement time-points was significantly associated with skin problems. The population risk attributable to these factors was 16%. This study quantified the contribution of occupational exposure factors to skin problems in the general working population of Norway. PMID:25941012

  13. The use of sensitive chemical antibodies for diagnosis: detection of low levels of EpCAM in breast cancer.

    Directory of Open Access Journals (Sweden)

    Sarah Shigdar

    Full Text Available EpCAM is expressed at low levels in a variety of normal human epithelial tissues, but is overexpressed in 70-90% of carcinomas. From a clinico-pathological point of view, this has both prognostic and therapeutic significance. EpCAM was first suggested as a therapeutic target for the treatment of epithelial cancers in the 1990s. However, following several immunotherapy trials, the results have been mixed. It has been suggested that this is due, at least in part, to an unknown level of EpCAM expression in the tumors being targeted. Thus, selection of patients who would benefit from EpCAM immunotherapy by determining EpCAM status in the tumor biopsies is currently undergoing vigorous evaluation. However, current EpCAM antibodies are not robust enough to be able to detect EpCAM expression in all pathological tissues. Here we report a newly developed EpCAM RNA aptamer, also known as a chemical antibody, which is not only specific but also more sensitive than current antibodies for the detection of EpCAM in formalin-fixed paraffin-embedded primary breast cancers. This new aptamer, together with our previously described aptamer, showed no non-specific staining or cross-reactivity with tissues that do not express EpCAM. They were able to reliably detect target proteins in breast cancer xenograft where an anti-EpCAM antibody (323/A3 showed limited or no reactivity. Our results demonstrated a more robust detection of EpCAM using RNA aptamers over antibodies in clinical samples with chromogenic staining. This shows the potential of aptamers in the future of histopathological diagnosis and as a tool to guide targeted immunotherapy.

  14. Studies on chemical protectors against radiation, 29; Protective effects of methanol extracts of various Chinese traditional medicines on skin injury induced by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng-Ming; Ohta, Setsuko; Shinoda, Masato (Hoshi Coll. of Pharmacy, Tokyo (Japan))

    1990-03-01

    In order to investigate useful protective medicines for the relief of skin injury induced by irradiation, 60 methanol extracts of Chinese traditional medicines were used in the test of protective potency on skin injury. ICR male mice at 6 weeks of age were whole-body irradiated with 1100R by using a soft X-ray generator (30 kVp, 10 mA, 190 R/min). Each methanol extract of these medicines was injected intraperitoneally into mice before or after irradiation. The degrees of skin injury were determined by a score system of skin reaction within the observation period from 21st to 40th day after irradiation. Protective potency of each medicine on skin injury was calculated from the maximum mean scores of administrated group and un-administrated group. As a result of these studies, the protective potency was detected in Unsei-in, Kumibinro-to, Keisi-syakuyaku-chimo-to, Keigai-rengyo-to, Gosyuyu-to, Koso-san, Saiko-seikan-to, Syo-kankyo-to, Syo-saiko-to, Syoma-kakkon-to, Sen-kan-meimoku-to, Zokumei-to, Sokei-kakketu-to, Bokuryo-in, Mao-to and Rikkunsi-to by intraperitoneal injection before irradiation. Of these effective medicines, only Unsei-in and Mao-to are shown to have a significant protective effect by intraperitoneal injection after irradiation. (author).

  15. Skin Cancer in Skin of Color

    OpenAIRE

    Bradford, Porcia T.

    2009-01-01

    Skin cancers in skin of color often present atypically or with advanced stage in comparison to Caucasian patients. Health care providers must maintain a high index of suspicion when examining skin lesions in skin of color.

  16. Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

    International Nuclear Information System (INIS)

    Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment

  17. Skin abscess

    Science.gov (United States)

    ... infection (often staphylococcus) A minor wound or injury Boils Folliculitis (infection in a hair follicle) A skin ... Elsevier Churchill Livingstone; 2009:chap 90. Read More Boils Endocarditis Folliculitis MRSA Osteomyelitis Update Date 11/12/ ...

  18. Skin graft

    Science.gov (United States)

    ... caused a large amount of skin loss Burns Cosmetic reasons or reconstructive surgeries where there has been ... Smoking increases your chance of problems such as slow healing. Ask your doctor or nurse for help ...

  19. Skin Pigment

    Science.gov (United States)

    ... This Article Medical Dictionary Also of Interest (Quiz) Vitiligo (Video) Hives Additional Content Medical News Overview of ... Version Pigment Disorders Overview of Skin Pigment Albinism Vitiligo Hyperpigmentation Melasma Melanin is the brown pigment that ...

  20. LSENS, A General Chemical Kinetics and Sensitivity Analysis Code for Homogeneous Gas-Phase Reactions. Part 2; Code Description and Usage

    Science.gov (United States)

    Radhakrishnan, Krishnan; Bittker, David A.

    1994-01-01

    LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part II of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part II describes the code, how to modify it, and its usage, including preparation of the problem data file required to execute LSENS. Code usage is illustrated by several example problems, which further explain preparation of the problem data file and show how to obtain desired accuracy in the computed results. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions. Part I (NASA RP-1328) derives the governing equations and describes the numerical solution procedures for the types of problems that can be solved by LSENS. Part III (NASA RP-1330) explains the kinetics and kinetics-plus-sensitivity-analysis problems supplied with LSENS and presents sample results.

  1. Deposition of Lead Sulfide Nanostructure Films on TiO2 Surface via Different Chemical Methods due to Improving Dye-Sensitized Solar Cells Efficiency

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: • TiO2 surface was fabricated by electrophoresis deposition method. • PbS nanostructure layers were deposited on the TiO2 surface via different chemical methods. • The effects of chemical deposition methods on the optical properties of fabricated surfaces were studied. • Dye-sensitized solar cells (DSSCs) were made with the fabricated TiO2/PbS surfaces. • The effects of different deposition methods on DSSC performance were investigated. -- Abstract: In this work TiO2 P25 was deposited successfully on the FTO glass by electrophoresis method. Different chemical methods were served for deposition of nanosized PbS such as chemical bath deposition (CBD) and successive ion layer adsorption and reaction (SILAR). Also in this paper, nanosized lead sulfide was successfully deposited on TiO2 surface by hydrothermal (HT) and microwave (MW) methods. Also TiO2/PbS nanocomposite was synthesized via a simple hydrothermal method and deposited on FTO glass by doctor blade (DB) technique. Dye sensitized solar cells were fabricated from prepared electrodes, Pt as counter electrode, dye solution and electrolyte. The effect of chemical deposition methods were investigated on surface quality, optical properties and solar cell efficiency. The observation showed that using different chemical methods for deposition of PbS on TiO2 surface is led to fabrication solar cells with different efficiencies and performances. The electrodes were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), cross-section SEM, UV–vis diffuse reflectance spectroscopy (DRS), energy dispersive X-ray analysis (EDX) spectroscopy, atomic force microscopy (AFM), cyclic voltammetry (CV) and UV–Vis spectroscopy. Dye-sensitized solar cells (DSSC) made by the fabricated electrodes as working electrode and then were investigated by current density-voltage (J-V) curve and electrochemical

  2. Old and stable soil organic matter is not necessarily chemically recalcitrant: Implications for modeling concepts and temperature sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleber, M.; Nico, P.S.; Plante, A.; Filley, T.; Kramer, M.; Swanston, C.; Sollins, P.

    2010-03-01

    Soil carbon turnover models generally divide soil carbon into pools with varying intrinsic decomposition rates. Although these decomposition rates are modified by factors such as temperature, texture, and moisture, they are rationalized by assuming chemical structure is a primary controller of decomposition. In the current work, we use near edge X-ray absorption fine structure (NEXAFS) spectroscopy in combination with differential scanning calorimetry (DSC) and alkaline cupric oxide (CuO) oxidation to explore this assumption. Specifically, we examined material from the 2.3-2.6 kg L{sup -1} density fraction of three soils of different type (Oxisol, Alfisol, Inceptisol). The density fraction with the youngest {sup 14}C age (Oxisol, 107 years) showed the highest relative abundance of aromatic groups and the lowest O-alkyl C/aromatic C ratio as determined by NEXAFS. Conversely, the fraction with the oldest C (Inceptisol, 680 years) had the lowest relative abundance of aromatic groups and highest O-alkyl C/aromatic C ratio. This sample also had the highest proportion of thermally labile materials as measured by DSC, and the highest ratio of substituted fatty acids to lignin phenols as indicated by CuO oxidation. Therefore, the organic matter of the Inceptisol sample, with a {sup 14}C age associated with 'passive' pools of carbon (680 years), had the largest proportion of easily metabolizable organic molecules with low thermodynamic stability, whereas the organic matter of the much younger Oxisol sample (107 years) had the highest proportion of supposedly stable organic structures considered more difficult to metabolize. Our results demonstrate that C age is not necessarily related to molecular structure or thermodynamic stability, and we suggest that soil carbon models would benefit from viewing turnover rate as codetermined by the interaction between substrates, microbial actors, and abiotic driving variables. Furthermore, assuming that old carbon is composed

  3. Hand wash and manual skin wipes

    NARCIS (Netherlands)

    Brouwer, D.H.; Boeniger, M.F.; Hemmen, J. van

    2000-01-01

    Hand wash and skin wipes are major techniques that have been used for dermal exposure sampling. Both techniques remove chemicals either deposited on or transferred to the skin contaminant layer by a combination of chemical and mechanical actions. The paper overviews identified methods and techniques

  4. Skin Cancer Screening

    Science.gov (United States)

    ... Genetics of Skin Cancer Skin Cancer Screening Research Skin Cancer Screening (PDQ®)–Patient Version What is screening? Go ... These are called diagnostic tests . General Information About Skin Cancer Key Points Skin cancer is a disease in ...

  5. Rapid and Simple Kinetics Screening Assay for Electrophilic Dermal Sensitizers using Nitrobenzenethiol

    OpenAIRE

    Chipinda, Itai; Ajibola, Risikat O.; Morakinyo, Moshood K.; Ruwona, Tinashe B.; Simoyi, Reuben H.; Siegel, Paul D.

    2010-01-01

    The need for alternatives to animal based skin sensitization testing has spurred research on the use of in-vitro, in silico and in chemico methods. Glutathione and other select peptides have been used to determine the reactivity of electrophilic allergens to nucleophiles, but these methods are inadequate to accurately measure rapid kinetics observed with many chemical sensitizers. A kinetic spectrophotometric assay involving the reactivity of electrophilic sensitizers to nitrobenzenethiol was...

  6. A controlled study of the effect of a mindfulness-based stress reduction technique in women with multiple chemical sensitivity, chronic fatigue syndrome, and fibromyalgia

    OpenAIRE

    Sampalli, Tara

    2009-01-01

    Tara Sampalli1, Elizabeth Berlasso1, Roy Fox1, Mark Petter21Nova Scotia Environmental Health Centre, Fall River, Nova Scotia, Canada; 2Doctoral Candidate, Department of Psychology, Dalhousie University, Halifax, CanadaBackground: The objective of this study was to examine the effect of a mindfulness-based stress reduction (MBSR) program on women diagnosed with conditions such as multiple chemical sensitivity (MCS), chronic fatigue syndrome (CFS), and fibromyalgia (FM). Methods: The interventi...

  7. Investigating Motivations for Women's Skin Bleaching in Tanzania

    Science.gov (United States)

    Lewis, Kelly M.; Robkin, Navit; Gaska, Karie; Njoki, Lillian Carol

    2011-01-01

    Why do many African women continue to use damaging skin-bleaching cosmetics that contain dangerous chemicals (e.g., mercury) that may increase their rates of infertility, skin cancer, and serious skin/brain/kidney disease? To address this question, our study investigated motivations driving the preservation of skin-bleaching practices in Tanzania.…

  8. Transient receptor potential ankyrin 1 activation enhances hapten sensitization in a T-helper type 2-driven fluorescein isothiocyanate-induced contact hypersensitivity mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Takahiro; Tamai, Takuma; Sahara, Yurina; Kurohane, Kohta [Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan); Watanabe, Tatsuo [Laboratory of Food Chemistry, School of Food and Nutritional Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan); Imai, Yasuyuki, E-mail: imai@u-shizuoka-ken.ac.jp [Laboratory of Microbiology and Immunology, School of Pharmaceutical Sciences, University of Shizuoka, 52‐1 Yada, Suruga-ku, Shizuoka City, Shizuoka 422‐8526 (Japan)

    2012-11-01

    Some chemicals contribute to the development of allergies by increasing the immunogenicity of other allergens. We have demonstrated that several phthalate esters, including dibutyl phthalate (DBP), enhance skin sensitization to fluorescein isothiocyanate (FITC) in a mouse contact hypersensitivity model, in which the T-helper type 2 (Th2) response is essential. On the other hand, some phthalate esters were found to activate transient receptor potential ankyrin 1 (TRPA1) cation channels on sensory neurons. We then found a positive correlation between the enhancing effects of several types of phthalate esters on skin sensitization to FITC and their ability to activate TRPA1. Here we examined the involvement of TRPA1 in sensitization to FITC by using TRPA1 agonists other than phthalate esters. During skin sensitization to FITC, the TRPA1 agonists (menthol, carvacrol, cinnamaldehyde and DBP) augmented the ear-swelling response as well as trafficking of FITC-presenting dendritic cells to draining lymph nodes. We confirmed that these TRPA1 agonists induced calcium influx into TRPA1-expressing Chinese hamster ovary (CHO) cells. We also found that TRPA1 antagonist HC-030031 inhibited DBP-induced calcium influx into TRPA1-expressing CHO cells. After pretreatment with this antagonist upon skin sensitization to FITC, the enhancing effect of DBP on sensitization was suppressed. These results suggest that TRPA1 activation will become a useful marker to find chemicals that facilitate sensitization in combination with other immunogenic haptens. -- Highlights: ► Role of TRPA1 activation was revealed in a mouse model of skin sensitization to FITC. ► TRPA1 agonists enhanced skin sensitization as well as dendritic cell trafficking. ► Dibutyl phthalate (DBP) has been shown to enhance skin sensitization to FITC. ► TRPA1 activation by DBP was inhibited by a selective antagonist, HC-030031. ► HC-030031 inhibited the enhancing effect of DBP on skin sensitization to FITC.

  9. Host-cell reactivation of uv-irradiated and chemically treated Herpes simplex virus type 1 strain MP in normal and xeroderma pigmentosum skin fibroblasts

    International Nuclear Information System (INIS)

    The host-cell reactivation of UV-irradiated and N-acetoxy-2-acetylaminofluorene-treated herpes simplex virus type 1 strain mp was studied in normal human skin fibroblasts and xeroderma pigmentosum skin fibroblasts from XP genetic complementation groups A-D and in an XP variant. The increasing relative order for the host-cell reactivation of both types of damaged virus in the different complementation groups is A = D < B < C; XP variant = normal controls. XP complementation group D cells, which manifest the most severe inhibition of her ability for both UV-irradiated and N-acetoxy-2-acetylaminofluorene-treated virus, can reactivate nitrogen mustard treated HSV-1 mp to the same extent as normal cells. Together, these results indicate that (1) Excision repair of UV and N-acetoxy-2-acetylaminofluorene DNA damaged viruses share a common rate limiting enzymatic step and (2) The repair defect in xeroderma pigmentosum cells plays little or no role in the recovery of nitrogen mustard treated virus. The results of studies on the effect of caffeine on the survival of both UV- and N-acetoxy-2-acetylaminofluorene-treated virus in normal and XP cells imply that the reactivation of HSV-1 mp is mediated by an excision repair process with little if any recovery contributed by post-replication repair mechanisms. The host-cell reactivation of N-acetoxy-2-acetylaminofluorene-treated HSV-1 mp was also correlated with the defective UV-induced unscheduled DNA synthesis in two skin fibroblast strains established from a skin biopsy obtained from each of two juvenile females who had been clinically diagnosed as xeroderma pigmentosum. These findings are discussed in relation to the further characterization of the xeroderma pigmentosum phenotype and their possible utilization for the selection and isolation of new mammalian cell DNA repair mutants

  10. Physical and chemical properties of tuna-skin and bovine-hide gelatin films with added aqueous oregano and rosemary extracts

    OpenAIRE

    Gómez Estaca, Joaquín; Montero García, Pilar; Fernández Martín, Fernando; Alemán, A.; Gómez Guillén, M. C.

    2009-01-01

    The properties of edible, gelatin-based films with added oregano or rosemary extract (two different concentrations) were studied. Gelatins from different sources (bovine-hides and tuna-skins) were employed with a view to elucidating how inherent gelatin characteristics may affect interaction of the gelatin with the polyphenols in the added extract and hence the properties of the resulting films. The bovine-hide gelatin reacted only slightly with the polyphenols in the extracts as shown by the...

  11. Cell Recruitment and Cytokines in Skin Mice Sensitized with the Vaccine Adjuvants: Saponin, Incomplete Freund’s Adjuvant, and Monophosphoryl Lipid A

    Science.gov (United States)

    Vitoriano-Souza, Juliana; Moreira, Nádia das Dores; Teixeira-Carvalho, Andréa; Carneiro, Cláudia Martins; Siqueira, Fernando Augusto Mathias; Vieira, Paula Melo de Abreu; Giunchetti, Rodolfo Cordeiro; Moura, Sandra Aparecida de Lima; Fujiwara, Ricardo Toshio; Melo, Maria Norma; Reis, Alexandre Barbosa

    2012-01-01

    Vaccine adjuvants are substances associated with antigens that are fundamental to the formation of an intense, durable, and fast immune response. In this context, the use of vaccine adjuvants to generate an effective cellular immune response is crucial for the design and development of vaccines against visceral leishmaniasis. The objective of this study was to evaluate innate inflammatory response induced by the vaccine adjuvants saponin (SAP), incomplete Freund’s adjuvant (IFA), and monophosphoryl lipid A (MPL). After a single dose of adjuvant was injected into the skin of mice, we analyzed inflammatory reaction, selective cell migration, and cytokine production at the injection site, and inflammatory cell influx in the peripheral blood. We found that all vaccine adjuvants were able to promote cell recruitment to the site without tissue damage. In addition, they induced selective migration of neutrophils, macrophages, and lymphocytes. The influx of neutrophils was notable at 12 h in all groups, but at other time points it was most evident after inoculation with SAP. With regard to cytokines, the SAP led to production of interleukin (IL)-2, IL-6, and IL-4. IFA promoted production of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, IL-6, IL-17, IL-4, and IL-10. We also observed that MPL induced high production of IL-2, TNF-α, and IFN-γ, in addition to IL-6, IL-17, and IL-10. In peripheral blood, values of certain cell populations in the local response changed after stimulation. Our data demonstrate that the three vaccine adjuvants stimulate the early events of innate immune response at the injection site, suggesting their ability to increase the immunogenicity of co-administered antigens. Moreover, this work provides relevant information about elements of innate and acquired immune response induced by vaccine adjuvants administered alone. PMID:22829882

  12. Skin-inspired electronic devices

    Directory of Open Access Journals (Sweden)

    Alex Chortos

    2014-09-01

    Full Text Available Electronic devices that mimic the properties of skin have potential important applications in advanced robotics, prosthetics, and health monitoring technologies. Methods for measuring tactile and temperature signals have progressed rapidly due to innovations in materials and processing methods. Imparting skin-like stretchability to electronic devices can be accomplished by patterning traditional electronic materials or developing new materials that are intrinsically stretchable. The incorporation of sensing methods with transistors facilitates large-area sensor arrays. While sensor arrays have surpassed the properties of human skin in terms of sensitivity, time response, and device density, many opportunities remain for future development.

  13. Influence of the physical–chemical properties of polyaniline thin films on the final sensitivity of varied field effect sensors

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Hugo José Nogueira Pedroza Dias, E-mail: hugodiasmello@usp.br; Heimfarth, Tobias; Mulato, Marcelo

    2015-06-15

    We investigated the use of electrodeposited polyaniline (PANI) thin sensing films in pH sensors. Two configurations of the Extended Gate Field Effect Transistor (EGFET) sensor were studied: the Single EGFET (S-EGFET) and the Instrumental Amplifier EGFET (IA-EGFET) setups. The films were analyzed in both systems and the sensitivity and linearity of each sensor were compared. Initial sensitivities (70–80 mV/pH) measured in the IA-EGFET were reduced due to polymer bulk protonation after a prior measurement in the S-EGFET system. Films with high amount of deposited polymer had their sensitivities least reduced. Bulk protonation occurred due to the step potential applied to the reference electrode in the S-EGFET system. These changes were also analyzed by scanning electron microscopy (SEM), visible reflectance spectroscopy and evaluation of CIE L*a*b* color scale. PANI pH EGFET sensors exhibited good linearity and stability that along with their high sensitivity, easy processing and low cost film production have large potential applications. - Highlights: • Electrodeposited polyaniline thin films were analyzed in two EGFET setups. • Polymer protonation provided changeable sensitivities. • Color and morphological variation confirm polymer aggregation and electrical changes.

  14. Influence of the physical–chemical properties of polyaniline thin films on the final sensitivity of varied field effect sensors

    International Nuclear Information System (INIS)

    We investigated the use of electrodeposited polyaniline (PANI) thin sensing films in pH sensors. Two configurations of the Extended Gate Field Effect Transistor (EGFET) sensor were studied: the Single EGFET (S-EGFET) and the Instrumental Amplifier EGFET (IA-EGFET) setups. The films were analyzed in both systems and the sensitivity and linearity of each sensor were compared. Initial sensitivities (70–80 mV/pH) measured in the IA-EGFET were reduced due to polymer bulk protonation after a prior measurement in the S-EGFET system. Films with high amount of deposited polymer had their sensitivities least reduced. Bulk protonation occurred due to the step potential applied to the reference electrode in the S-EGFET system. These changes were also analyzed by scanning electron microscopy (SEM), visible reflectance spectroscopy and evaluation of CIE L*a*b* color scale. PANI pH EGFET sensors exhibited good linearity and stability that along with their high sensitivity, easy processing and low cost film production have large potential applications. - Highlights: • Electrodeposited polyaniline thin films were analyzed in two EGFET setups. • Polymer protonation provided changeable sensitivities. • Color and morphological variation confirm polymer aggregation and electrical changes

  15. Air Pollution and the skin

    Directory of Open Access Journals (Sweden)

    Eleni eDrakaki

    2014-05-01

    Full Text Available The increase of air pollution over the years has major effects on the human skin. The skin is exposed to ultraviolet radiation (UVR and environmental air pollutants such as polycyclic aromatic hydrocarbons (PAHs, volatile organic compounds (VOCs, oxides, particulate matter (PM, ozone (O3 and cigarette smoke. Although human skin acts as a biological shield against pro-oxidative chemical and physical air pollutants, the prolonged or repetitive exposure to high levels of these pollutants may have profound negative effects on the skin. Exposure of the skin to air pollutants has been associated with skin aging and inflammatory or allergic skin conditions such as atopic dermatitis, eczema, psoriasis or acne, while skin cancer is among the most serious effects. On the other hand, some air pollutants (ie, ozone, nitrogen dioxide, and sulfur dioxide and scattering particulates (clouds and soot in the troposphere reduce the effects of shorter wavelength UVR and significant reductions in UV irradiance have been observed in polluted urban areas.

  16. Demonstration of a rapidly-swept external cavity quantum cascade laser for rapid and sensitive quantification of chemical mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Brumfield, Brian E.; Taubman, Matthew S.; Phillips, Mark C.

    2016-02-13

    A rapidly-swept external cavity quantum cascade laser (ECQCL) system for fast open-path quantification of multiple chemicals and mixtures is presented. The ECQCL system is swept over its entire tuning range (>100 cm-1) at frequencies up to 200 Hz. At 200 Hz the wavelength tuning rate and spectral resolution are 2x104 cm-1/sec and < 0.2 cm-1, respectively. The capability of the current system to quantify changes in chemical concentrations on millesecond timescales is demonstrated at atmospheric pressure using an open-path multi-pass cell. The detection limits for chemicals ranged from ppb to ppm levels depending on the absorption cross-section.

  17. Contact dermatitis and other skin conditions in instrumental musicians

    Directory of Open Access Journals (Sweden)

    Freitag Marcus

    2004-04-01

    Full Text Available Abstract Background The skin is important in the positioning and playing of a musical instrument. During practicing and performing there is a permanent more or less intense contact between the instrument and the musician's skin. Apart from aggravation of predisposed skin diseases (e.g., atopic eczema or psoriasis due to music-making, specific dermatologic conditions may develop that are directly caused by playing a musical instrument. Methods To perform a systematic review on instrument-related skin diseases in musicians we searched the PubMed database without time limits. Furthermore we studied the online bibliography "Occupational diseases of performing artist. A performing arts medicine bibliography. October, 2003" and checked references of all selected articles for relevant papers. Results The most prevalent skin disorders of instrumental musicians, in particular string instrumentalists (e.g., violinists, cellists, guitarists, woodwind players (e.g., flautists, clarinetists, and brass instrumentalists (e.g., trumpeters, include a variety of allergic contact sensitizations (e.g., colophony, nickel, and exotic woods and irritant (physical-chemical noxae skin conditions whose clinical presentation and localization are usually specific for the instrument used (e.g., "fiddler's neck", "cellist's chest", "guitar nipple", "flautist's chin". Apart from common callosities and "occupational marks" (e.g., "Garrod's pads" more or less severe skin injuries may occur in musical instrumentalists, in particular acute and chronic wounds including their complications. Skin infections such as herpes labialis seem to be a more common skin problem in woodwind and brass instrumentalists. Conclusions Skin conditions may be a significant problem not only in professional instrumentalists, but also in musicians of all ages and ability. Although not life threatening they may lead to impaired performance and occupational hazard. Unfortunately, epidemiological

  18. When beauty is only skin deep; optimizing the sensitivity of specular neutron reflectivity for probing structure beneath the surface of thin filmsa)

    Science.gov (United States)

    Majkrzak, Charles F.; Carpenter, Elisabeth; Heinrich, Frank; Berk, Norman F.

    2011-11-01

    Specular neutron reflectometry has become an established probe of the nanometer scale structure of materials in thin film and multilayered form. It has contributed especially to our understanding of soft condensed matter of interest in polymer science, organic chemistry, and biology and of magnetic hard condensed matter systems. In this paper we examine a number of key factors which have emerged that can limit the sensitivity of neutron reflection as such a probe. Among these is loss of phase information, and we discuss how knowledge about material surrounding a film of interest can be applied to help resolve the problem. In this context we also consider what role the quantum phenomenon of interaction-free measurement might play in enhancing the statistical efficiency for obtaining reflectivity or transmission data.

  19. Airway morphology and function of rats following dermal sensitization and respiratory challenge with low molecular weight chemicals

    NARCIS (Netherlands)

    Arts, J.H.E.; Kuper, C.F.; Spoor, S.M.; Bloksma, N.

    1998-01-01

    Local lymph node activation and increased total serum IgE levels are suggested to be predictive parameters of airway hypersensitivity caused by low molecular weight (LMW) chemicals. Whether increases of total serum IgE are indicative of actual induction of specific airway reactions (morphological an

  20. 对苯二胺对小鼠淋巴细胞的增殖效应及其皮肤致敏性研究%STUDY ON EFFECT OF PARAPHENYLENEDIAMINE ON LYMPHOCYTES PROLIFERATION IN MICE AND SKIN SENSITIZATION POTENCY

    Institute of Scientific and Technical Information of China (English)

    何国群; 郑穗生; 谢晓萍; 李庆; 古梅英; 谭小华; 张龙杰

    2011-01-01

    [Objective] To study the effects of paraphenylenediamine on lymphocytes proliferation in mice and skin sen-sitization potency. [Methods] Mice were treated with 0.3%, 1.0%, 3.0% and 6.0% paraphenylenediamine (PPD) and four hair dyes contained 0%, 1.5%, 3.0% and 6.0% PPD at the dorsum of each ear once daily for three consecutive days. At the forth day, the mice were injected intraperitoneally with BrdU. At the fifth day, they were sacrificed and the draining auricular nodes were excised and weighed. Single lymphocytes suspensions of lymph node cells were prepared and lymphocytes number were counted. Used an enzyme-linked immunosorbent assay (ELISA) to measure the level of BrdU incorporation. Skin sensitiza-tion test in guinea pigs were executed to four hair dyes contained 0%, 1.5%, 3.0% and 6.0% of PPD. [Results] Comparedwith the vehicle-treated control group, the node weight, lymphocytes number and BrdU label index of the mice treated with PPD or hair dyes contained various concentration PPD were significantly increased. 3.0% and 6.0% of PPD and hair dyes contained 3.0% and 6.0% of PPD showed positive responses; Hair dyes contained 3.0% and 6.0% of PPD were classified as weak and mild sensitizers in skin sensitization test in guinea pig. [Conclusion] Lymphocyte proliferation can be caused by PPD in skin contact. Hair dyes contained 3.0% and 6.0% of PPD have skin sensitization potency.%[目的]探讨不同浓度对苯二胺原科和含对苯二胺的染发剂经皮肤接触对实验动物淋巴细胞的免疫效应和皮肤致敏作用.[方法]取浓度为0.3%、1.0%、3.0%、6.0%的对苯二胺原料和含对苯二胺为0%、1.5%、3.0%、6.0%的染发剂涂抹于小鼠耳背,连续3d,d4小鼠腹腔注射BrdU,d5摘取小鼠耳部淋巴结,制取单细胞悬液并计算淋巴细胞数,采用ELISA技术测定BrdU标记指数;取含对苯二胺为0%、1.5%、3.0%、6.0%的染发剂进行豚鼠皮肤变态反应实验.[结果]与阴性(溶剂

  1. Skin Care and Aging

    Science.gov (United States)

    ... page please turn Javascript on. Skin Care and Aging How Aging Affects Skin Your skin changes with age. It ... if they bother you. See additional resources on aging skin, including information on treatment options, specific conditions, ...

  2. Skin Cancer Foundation

    Science.gov (United States)

    ... Host a Fundraising Event | About Us | Store The Skin Cancer Foundation The Skin Cancer Foundation is the ... A "Sunscreen Gene"? Skin Cancer Facts & Statistics The Skin Cancer Foundation's Champions for Change Gala 2016 Learn ...

  3. Skin Pigmentation Disorders

    Science.gov (United States)

    Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or ...

  4. The evaluation of the impact of age, skin tags, metabolic syndrome, body mass index, and smoking on homocysteine, endothelin-1, high-sensitive C-reactive protein, and on the heart

    Directory of Open Access Journals (Sweden)

    Omar Soliman El Safoury

    2013-01-01

    Full Text Available Background: Skin tags (STs are small, pedunculated skin-colored or brown papules that occur around any site where skin folds occur. The literature is short of comprehensive and controlled clinical studies aimed to evaluate the atherogenic risk factors in patients with STs. Aim of Work: The aim of this study is to evaluate the impact of age, STs, metabolic syndrome (METs, body mass index (BMI, and smoking on homocysteine (Hcy, endothelin-1 (ET-1, high-sensitive C-reactive protein (Hs-CRP, and on cardiovascular diseases. Materials and Methods: This study included 30 cardiac patients with STs, 30 non-cardiac patients with STs, and 30 healthy controls with neither heart disease nor STs. History of smoking, measurement of height, weight, BMI, waist circumference (WC, blood pressure, STs number, color, acanthosis nigricans, estimation of serum level of fasting glucose, triglycerides (TGs, cholesterol, high-dense lipoproteins (HDL, Hcy, ET-1, Hs-CRP, and the presence of the METs were elicited in the three groups. Results: Regarding the Hcy, ET-1, and Hs-CRP, the cardiac-STs group showed the highest levels and the control group showed the least ( P < 0.001. The percents of patients with METs were 56.7% in the cardiac-STs, 40% in the non-cardiac-STs, and 0% in the control group ( P < 0.001. Mean BMI exceeded the limit of obesity in the cardiac-STs group (30.9 ± 3.9 and the non-cardiac-STs group (32.6 ± 6 and was normal in the control group (24.7 ± 2.8. Hyperpigmented STs were present in 66.7% of the cardiac-STs group. Multivariate regression analysis for the independent effectors on Hcy level were the presence of STs ( P < 0.001, METs ( P = 0.001, and BMI ( P = 0.024. Regarding ET-1, the effectors were the presence of STs and METs ( P = 0.032. For Hs-CRP, effectors were the presence of STs ( P < 0.001 and smoking ( P = 0.040. Multivariate logistic regression of the predictors of cardiac disease showed that the independent predictors of the occurrence

  5. Skin Substitutes

    OpenAIRE

    Zavan, Barbara; Vindigni, Vincenzo; Cortivo, Roberta; Abatangelo, Giovanni

    2010-01-01

    The many studies conducted so far reveal that Tissue Engineering of the skin is only at the beginning of its use in human applications. Burns patients were the first targets for such tissue substitutes, then chronic diseases, such as venous ulcers, have followed. The more experience is gained from the surgeon, the more feedback for the basic scientist to improve the product and to broaden clinical indications. Nowadays, progress in cell culture and biomedical material technologies have added ...

  6. Skin aging:

    OpenAIRE

    Puizina-Ivić, Neira

    2008-01-01

    There are two main processes that induce skin aging: intrinsic and extrinsic. A stochastic process that implies random cell damage as a result of mutations during metabolic processes due to the production of free radicals is also implicated. Extrinsic aging is caused by environmental factors such as sun exposure, air pollution, smoking, alcohol abuse, and poor nutrition. Intrinsicaging reflects the genetic background and depends on time. Various expressions of intrinsic aging include smooth, ...

  7. 改性塔拉微粉兔皮复鞣工艺中的应用%Chemical Modification of Tara Powder and Application in Rabbit Skin

    Institute of Scientific and Technical Information of China (English)

    吴樊花; 刘公岩; 张宗才

    2013-01-01

    The tara powder was modified and applied in the retanning of rabbit skin.The shrink-temperature and the free formaldehyde content of the skin retanned by modified-tara were determined.The result shows that the application of modified tara in retanning decreases the formaldehyde dosage used in the process.The solftness and fullness of the fur tanned by this method are well,which comply with the requirements of eco-fur.%对塔拉微粉进行改性后,将其应用于兔皮复鞣工艺中,考察了兔皮的收缩温度及游离甲醛含量等指标,结果表明:在复鞣阶段使用改性塔拉单宁,大大降低了兔皮复鞣工艺中甲醛的用量,且鞣制后兔皮皮板的丰满度、弹性较好,符合生态裘皮的要求.

  8. Porcine skin flow-through diffusion cell system.

    Science.gov (United States)

    Baynes, R E

    2001-11-01

    Porcine Skin Flow-Through Diffusion Cell System (Ronald E. Baynes, North Carolina State University, Raleigh, North Carolina). Porcine skin can be used in a diffusion cell apparatus to study the rate and extent of absorption of topically applied chemicals through the skin. Although the skin of a number of animals can be used in this system, that of the pig most closely approximates human skin anatomically and physiologically.

  9. The role of glutathione S-transferase and claudin-1 gene polymorphisms in contact sensitization

    DEFF Research Database (Denmark)

    Ross-Hansen, K; Linneberg, A; Johansen, J D;

    2013-01-01

    BACKGROUND: Contact sensitization is frequent in the general population and arises from excessive or repeated skin exposure to chemicals and metals. However, little is known about its genetic susceptibility. OBJECTIVES: To determine the role of polymorphisms of glutathione S-transferase (GST) genes...

  10. A controlled study of the effect of a mindfulness-based stress reduction technique in women with multiple chemical sensitivity, chronic fatigue syndrome, and fibromyalgia

    Directory of Open Access Journals (Sweden)

    Tara Sampalli

    2009-04-01

    Full Text Available Tara Sampalli1, Elizabeth Berlasso1, Roy Fox1, Mark Petter21Nova Scotia Environmental Health Centre, Fall River, Nova Scotia, Canada; 2Doctoral Candidate, Department of Psychology, Dalhousie University, Halifax, CanadaBackground: The objective of this study was to examine the effect of a mindfulness-based stress reduction (MBSR program on women diagnosed with conditions such as multiple chemical sensitivity (MCS, chronic fatigue syndrome (CFS, and fibromyalgia (FM. Methods: The intervention group underwent a 10-week MBSR program. Symptoms Checklist Inventory (SCL-90R was used as outcome measure and was administered before the start of the program (pre-, immediately upon completion (post- and at three-month follow-up. Women on the wait list to receive treatment at the Nova Scotia Environmental Health Centre were used as control subjects for the study.Results: A total of 50 participants in the intervention group and 26 in the wait-list controls group were recruited for this study. Global scores in the intervention group reached statistical significance pre-post (<0.0001 and at pre-follow-up (<0.0001 while the global scores in the control group remained the same. Five of nine and eight of nine subscales of the SCL-90R showed improvement of statistical significance in MBSR group following treatment and at three-month follow-up.Conclusions: The study showed the importance of complementary interventions such as MBSR techniques in the reduction of psychological distress in women with chronic conditions.Keywords: chronic conditions, multiple chemical sensitivity, mindfulness-based stress reduction, chemical sensitivity

  11. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    Science.gov (United States)

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO. PMID:26653465

  12. The Different Sensitive Behaviors of a Hydrogen-Bond Acidic Polymer-Coated SAW Sensor for Chemical Warfare Agents and Their Simulants

    Directory of Open Access Journals (Sweden)

    Yin Long

    2015-07-01

    Full Text Available A linear hydrogen-bond acidic (HBA linear functionalized polymer (PLF, was deposited onto a bare surface acoustic wave (SAW device to fabricate a chemical sensor. Real-time responses of the sensor to a series of compounds including sarin (GB, dimethyl methylphosphonate (DMMP, mustard gas (HD, chloroethyl ethyl sulphide (2-CEES, 1,5-dichloropentane (DCP and some organic solvents were studied. The results show that the sensor is highly sensitive to GB and DMMP, and has low sensitivity to HD and DCP, as expected. However, the sensor possesses an unexpected high sensitivity toward 2-CEES. This good sensing performance can’t be solely or mainly attributed to the dipole-dipole interaction since the sensor is not sensitive to some high polarity solvents. We believe the lone pair electrons around the sulphur atom of 2-CEES provide an electron-rich site, which facilitates the formation of hydrogen bonding between PLF and 2-CEES. On the contrary, the electron cloud on the sulphur atom of the HD molecule is offset or depleted by its two neighbouring strong electron-withdrawing groups, hence, hydrogen bonding can hardly be formed.

  13. Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-ray FEL

    CERN Document Server

    Salen, P; Schmidt, H T; Thomas, R D; Larsson, M; Feifel, R; Piancastelli, M N; Fang, L; Murphy, B; Osipov, T; Berrah, N; Kukk, E; Ueda, K; Bozek, J D; Bostedt, C; Wada, S; Richter, R; Feyer, V; Prince, K C

    2012-01-01

    We have performed X-ray two-photon photoelectron spectroscopy (XTPPS) using the Linac Coherent Light Source (LCLS) X-ray free-electron laser (FEL) in order to study double core-hole (DCH) states of CO2, N2O and N2. The experiment verifies the theory behind the chemical sensitivity of two-site (ts) DCH states by comparing a set of small molecules with respect to the energy shift of the tsDCH state and by extracting the relevant parameters from this shift.

  14. Multiple chemical sensitivity multiorgan dysesthesia, multiple symptom complex, and multiple confusion: problems in diagnosing the patient presenting with unexplained multisystemic symptoms.

    Science.gov (United States)

    Salvaggio, J E; Terr, A I

    1996-11-01

    Patients are presenting in increasing numbers with multiorgan symptoms allegedly resulting from exposure to environmental chemicals. Among the symptoms expressed by patients with alleged multiple chemical sensitivities (MCS) are profound fatigue, mental confusion, myalgia, depression, anxiety, dizziness, headache, insomnia, loss of appetite, and numbness of the extremities, all in the absence of objective physical signs. Diagnostic criteria to assess the effects of environmental agents on organ systems are sorely needed because patients with MCS often have no tissue pathology or physiological abnormalities, but often do have diagnosable psychiatric illnesses. In treating patients with MCS, the physician should first perform a complete history and physical examination, including a comprehensive evaluation of chemical exposure. If the findings strongly suggest the presence of disease related to particular organ systems, further diagnostic evaluation should be undertaken. If abnormal findings are absent, psychiatric advice may be useful. The physician should keep an open mind about MCS but must also remember that a cause-effect relationship between exposure to multiple chemicals and symptoms has not been established.

  15. Cutaneous skin tag

    Science.gov (United States)

    Skin tag; Acrochordon; Fibroepithelial polyp ... have diabetes. They are thought to occur from skin rubbing against skin. ... The tag sticks out of the skin and may have a short, narrow stalk connecting it to the surface of the skin. Some skin tags are as long as ...

  16. Influence of NH3.H2O additive on the photovoltaic performance of dye-sensitized solar cells with chemical sintered scattering layers

    International Nuclear Information System (INIS)

    Graphical abstract: Chemical sintered bi-functional nanocrystalline TiO2 layers for highly efficient photoelectrodes. Display Omitted Highlights: → A chemical sintered bi-functional nanocrystalline TiO2 layer was prepared. → The nanocrystalline TiO2 layer can offer both light-scattering and electron generating properties. → The DSSC with this nanocrystalline TiO2 layer in the photoelectrode shows obviously enhanced photovoltaic performance. → The influence of additional amount of NH3.H2O chemical sintering agent on the photovoltaic performance of DSSCs was studied. - Abstract: A bi-functional nanocrystalline TiO2 (nc-TiO2) layer able to offer both light-scattering and electron generating properties was prepared with a simple method through adding the basic NH3.H2O agent into an acid nc-TiO2 paste to form some big rod-like nc-TiO2 aggregates by the chemical sintering process. The influence of additional amount of NH3.H2O on the photovoltaic performance of the dye-sensitized solar cell with this bi-functional nc-TiO2 layer in the photoelectrode was studied. It was found that through controlling the additional amount of NH3.H2O and the thickness of the bi-functional nc-TiO2 layer, the highest energy conversion efficiency about 8.11% could be obtained, which was much higher than that of the dye-sensitized solar cell containing a single nc-TiO2 layer prepared with the original acid nc-TiO2 paste (4.34%).

  17. Influence of NH{sub 3}.H{sub 2}O additive on the photovoltaic performance of dye-sensitized solar cells with chemical sintered scattering layers

    Energy Technology Data Exchange (ETDEWEB)

    Lan Zhang, E-mail: lanzhang@hqu.edu.cn [Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Quanzhou 362021 (China); Key Laboratory of Functional Materials for Fujian Higher Education, Huaqiao University, Quanzhou 362021 (China); Institute of Materials Physical Chemistry, Huaqiao University, Quanzhou 362021 (China); Wu Jihuai, E-mail: jhwu@hqu.edu.cn [Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Quanzhou 362021 (China); Key Laboratory of Functional Materials for Fujian Higher Education, Huaqiao University, Quanzhou 362021 (China); Institute of Materials Physical Chemistry, Huaqiao University, Quanzhou 362021 (China); Lin Jianming; Huang, Miaoliang [Engineering Research Center of Environment-Friendly Functional Materials, Ministry of Education, Huaqiao University, Quanzhou 362021 (China); Key Laboratory of Functional Materials for Fujian Higher Education, Huaqiao University, Quanzhou 362021 (China); Institute of Materials Physical Chemistry, Huaqiao University, Quanzhou 362021 (China)

    2011-11-30

    Graphical abstract: Chemical sintered bi-functional nanocrystalline TiO{sub 2} layers for highly efficient photoelectrodes. Display Omitted Highlights: > A chemical sintered bi-functional nanocrystalline TiO{sub 2} layer was prepared. > The nanocrystalline TiO{sub 2} layer can offer both light-scattering and electron generating properties. > The DSSC with this nanocrystalline TiO{sub 2} layer in the photoelectrode shows obviously enhanced photovoltaic performance. > The influence of additional amount of NH{sub 3}.H{sub 2}O chemical sintering agent on the photovoltaic performance of DSSCs was studied. - Abstract: A bi-functional nanocrystalline TiO{sub 2} (nc-TiO{sub 2}) layer able to offer both light-scattering and electron generating properties was prepared with a simple method through adding the basic NH{sub 3}.H{sub 2}O agent into an acid nc-TiO{sub 2} paste to form some big rod-like nc-TiO{sub 2} aggregates by the chemical sintering process. The influence of additional amount of NH{sub 3}.H{sub 2}O on the photovoltaic performance of the dye-sensitized solar cell with this bi-functional nc-TiO{sub 2} layer in the photoelectrode was studied. It was found that through controlling the additional amount of NH{sub 3}.H{sub 2}O and the thickness of the bi-functional nc-TiO{sub 2} layer, the highest energy conversion efficiency about 8.11% could be obtained, which was much higher than that of the dye-sensitized solar cell containing a single nc-TiO{sub 2} layer prepared with the original acid nc-TiO{sub 2} paste (4.34%).

  18. THE INTERACTION MECHANISM OF METHIONINE AND CHEMICAL SENSITIZERS%蛋氨酸与化学增感剂的相互作用机理

    Institute of Scientific and Technical Information of China (English)

    张宜恒; 冯少红; 闫天堂; 宫竹芳; 俞书勤; 庄思永; 彭必先

    2001-01-01

    The changes of the chemical states and the relative contents of sulfur,gold,carbon and oxygen after methionine reacted with different chemical sensitizers are studied by ESCA scanning technique of X-ray Photoelectron Spectroscopy(CPS).The results indicated that the interaction mechanism of methionine reacted with different chemical sensitizers is not identical.Any oxidation-reduction reaction did not occurred between methionine and sulfur sensitizer,they could coexist steadily in the same system.The methionine was oxidized to methionine sulfoxide,in the same time reducing Au3+ to gold atom.The hydroxy of methionine could coordinate Au,forming Au-O-C coordinate metal complex.After S+Au sensitizers had been immersed into methionine system,oxidation-reduction reaction occurred between added thiosulfate and Au3+,methionine could coordinate Au which was reduced by sulfur sensitizer,also forming Au-O-C coordinate metal complex.%运用X射线光电子能谱(XPS)的ESCA扫描技术研究了蛋氨酸与不同化学增感剂相互作用及其中的硫、金、碳和氧等元素的化学形态和相对含量的变化规律.发现蛋氨酸与不同的化学增感剂的反应机理是不尽相同的.蛋氨酸与S增感剂不会发生任何化学反应,它们可以稳定地共存于同一体系之中;蛋氨酸可以将全部Au3+增感剂还原为Au,其自身部分被氧化为蛋氨酸亚砜,并且在其脱质子的羟基部位与Au形成Au-O-C结构的金属配合物.向蛋氨酸体系中加入S+Au增感剂后,体系中的氧化还原反应发生在外加的Au3+和S2O32-之间,此时蛋氨酸的作用是将被S增感剂还原的Au络合,亦形成Au-O-C结构的配合物.

  19. Xenobiotic-metabolizing enzymes in the skin of rat, mouse, pig, guinea pig, man, and in human skin models

    OpenAIRE

    Oesch, F; Fabian, E.; Guth, K.; Landsiedel, R.

    2014-01-01

    Abstract The exposure of the skin to medical drugs, skin care products, cosmetics, and other chemicals renders information on xenobiotic-metabolizing enzymes (XME) in the skin highly interesting. Since the use of freshly excised human skin for experimental investigations meets with ethical and practical limitations, information on XME in models comes in the focus including non-human mammalian species and in vitro skin models. This review attempts to summarize the information available in the ...

  20. 青海湖裸鲤体表白点病病原菌的分离与药敏试验%Identification and Drug Sensitivity Test of Pathogenic Bacteria of White-spot Disease From Skin Surface of Gymnocypris przewaiskii

    Institute of Scientific and Technical Information of China (English)

    李增魁; 李长忠; 康明; 圈华; 张勤文; 刘道鑫; 马东红; 夏若措毛; 李英

    2015-01-01

    To assure the pathogenic bacteria of white-spot disease from skin surface in Gymnocypris prze-waiskii and treat the disease,three bacterial strains (Citrobacter freundii ,Aeromonas veronii ,Morganella fulton)were isolated from naturally infected Gymnocypris przewaiskii and identified by morphology,cul-tural characteristics,physical and chemical characters,and 16 S rRNA sequence analysis.The three strains were Gram negative.Colony morphologies were consistent.Drug sensitivity test revealed that the three strains were highly sensitive to cefepime,amikacin and gentamicin,which will benefit the treatment of dis-ease in Gymnocypris przewaiskii .%为确定养殖青海湖裸鲤(Gymnocypris przewaiskii )体表白点病的病原,分别对患病鱼白色点状囊泡样物进行了细菌分离、生理生化特性鉴定、16 S rRNA 基因分析和药敏感试验,分离到了以弗氏柠檬酸杆菌(Citrobacter freundii )、维氏气单胞菌(Aeromonas veronii ,AV)和摩氏摩根菌(Morganella fulton )为代表的菌落形态一致、革兰阴性细菌;且分离到的3种菌都对头孢吡肟、丁胺卡那霉素、庆大霉素等药物敏感。

  1. Clinical observation of Qingreliangxue decoction with medical skin-care products (winona sensitive skin moisture recovery cream)on Skin Barrier function in patients with facial corticosteroid addictive dermatitis%清热凉血汤联合薇诺娜舒敏保湿修复霜改善面部糖皮质激素依赖性皮炎的临床观察

    Institute of Scientific and Technical Information of China (English)

    徐佳; 杨慧敏

    2011-01-01

    objective: To investigate the clinical efficacy of QingReLiangXue decoction with winona sensitive skin moisture recovery cream on skin barrier function in patients with facial corticosteroid Addictive Dermatitis. Methods: sixtytwo patients were randomly assigned to two groups, the 31 in the treated group with QRLXD, while the 31 in the control group with tablet, 28 days as a course. Results: two were dropped out. The total effective rate was 80%(24/30)in the treated group and 30%(10/30)in the control group respectively. Statistical difference was detected between the two groups; the scores lowered after treatment in the two groups (P<0.01); the improvements were more significant in the QRLX group in terms of aestus, erythema,tumentia and papular.squama(P<0.001), but not in prupitus and drying. Conclusion QingReLiangXue decoction with winona sensitive skin moisture recovery cream has significant clinical efficacy on CsAD, they could recover the injured facial skin barrier function.%目的:研究清热凉血汤联合薇诺娜舒敏保湿修复霜治疗面部糖皮质激素依赖性皮炎的临床疗效.方法:62例患者随机分为治疗组31例和对照组31例.治疗组:口服清热凉血汤;对照组;口服氯雷他定片.两组同时予3%硼酸洗液湿敷,外用薇诺娜舒敏保湿修复霜.28d为1个疗程.结果:两组各失访1例.治疗组显效率为80.0%(24/30)例,对照组显效率为33.3%(10/30)例,治疗组优于对照组(P<0.01);治疗后,两组症状评分较治疗前均明显下降,治疗组优于对照组(P<0.01);治疗组在改善皮损灼热、红斑、肿胀、丘疹方面优于对照组(P<0.001),而在改善瘙痒、干燥方面,两组均有良好效果,无统计学差异.结论:清热凉血汤联合薇诺娜舒敏保湿修复霜可以明显改善面部糖皮质激素依赖性皮炎症状,恢复皮肤屏障功能,安全有效.

  2. Pygmy Resonances and Neutron Skins

    CERN Document Server

    Piekarewicz, J

    2010-01-01

    Motivated by a recent experiment, the distribution of electric dipole strength in the neutron-rich 68Ni isotope was computed using a relativistic random phase approximation with a set of effective interactions that - although well calibrated - predict significantly different values for the neutron-skin thickness in 208Pb. The emergence of low-energy "Pygmy" strength that exhausts about 5-8% of the energy weighted sum rule (EWSR) is clearly identified. In addition to the EWSR, special emphasis is placed on the dipole polarizability. In particular, our results suggest a strong correlation between the dipole polarizability of 68Ni and the neutron-skin thickness of 208Pb. Yet we find a correlation just as strong and an even larger sensitivity between the neutron-skin thickness of 208Pb and the fraction of the dipole polarizability exhausted by the Pygmy resonance. These findings suggest that the dipole polarizability may be used as a proxy for the neutron skin.

  3. The skin-blanching assay.

    Science.gov (United States)

    Smit, P; Neumann, H A M; Thio, H B

    2012-10-01

    The skin-blanching assay is used for the determination and bioequivalence of dermatologic glucocorticoids (GCs). The exact mechanism of the production of blanching is not fully understood, but it is considered that local vasoconstriction of the skin microvasculature and the consequent blood-flow reduction cause this phenomenon. Several factors influence skin blanching, including drug concentration, duration of application, nature of vehicle, occlusion, posture and location. The intensity of vasoconstriction can be measured in several ways: visual or quantitative methods, such as reflectance spectroscopy, thermography, laser Doppler velocimetry and chromametry. In literature, contradicting results in the correlation of the skin-blanching assay with different tests to determine GC sensitivity have been reported, limiting its clinical usefulness.

  4. Quality control of automotive engine oils with mass-sensitive chemical sensors--QCMs and molecularly imprinted polymers.

    Science.gov (United States)

    Dickert, F L; Forth, P; Lieberzeit, P A; Voigt, G

    2000-04-01

    Molecularly imprinted polyurethanes were used as sensor materials for monitoring the degradation of automotive engine oils. Imprinting with characteristic oils permits the analysis of these complex mixtures without accurately knowing their composition. Mass-sensitive quartz crystal microbalances (QCMs) coated with such layers exhibit mass effects in addition to frequency shifts caused by viscosity, which can be compensated by an uncoated quartz or a non-imprint layer. Incorporation of degradation products into the imprinted coatings is a bulk phenomenon, which is proven by variation of the sensor layer height. Therefore, the resulting sensor effects are determined by the degradation products in the oil. PMID:11227411

  5. Lipid-polymer nanoparticles encapsulating doxorubicin and 2'-deoxy-5-azacytidine enhance the sensitivity of cancer cells to chemical therapeutics.

    Science.gov (United States)

    Su, Xianwei; Wang, Zhaohui; Li, Lili; Zheng, Mingbin; Zheng, Cuifang; Gong, Ping; Zhao, Pengfei; Ma, Yifan; Tao, Qian; Cai, Lintao

    2013-05-01

    Nanomedcine holds great potential in cancer therapy due to its flexibility on drug delivery, protection, releasing, and targeting. Epigenetic drugs, such as 2'-deoxy-5-azacytidine (DAC), are able to cause reactive expression of tumor suppressor genes (TSG) in human cancers and, therefore, might be able to enhance the sensitivity of cancer cells to chemotherapy. In this report, we fabricated a lipid-polymer nanoparticle for codelivery of epigenetic drug DAC and traditional chemotherapeutic drug (DOX) to cancer cells and monitored the growth inhibition of the hybrid nanoparticles (NPs) on cancer cells. Our results showed that NPs encapsulating DAC, DOX, or both, could be effectively internalized by cancer cells. More importantly, incorporating DAC into NPs significantly enhanced the sensitivity of cancer cells to DOX by inhibiting cell growth rate and inducing cell apoptosis. Further evidence indicated that DAC encapsulated by NPs was able to rescue the expression of silenced TSG in cancer cells. Overall our work clearly suggested that the resulting lipid-polymer nanoparticle is a potential tool for combining epigenetic therapy and chemotherapy. PMID:23570548

  6. Radiation sensitizations at DNA-level by chemical and biological agents. Coordinated programme on improvement of radiotherapy of cancer using modifiers of radiosensitivity of cells

    International Nuclear Information System (INIS)

    Radiation sensitization by chemical agents at DNA level is discussed. Procaine, Halothan and Metronidazole showed no significant effect on unscheduled DNA synthesis (UDS) in mouse spleen cells, investigated by autoradiography and no effect on rejoining of DNA single strand breaks after gamma or UV irradiation. Oxyphenbutazon and prednisolone reduced the replicative DNA synthesis in vitro and in vivo but there was only little effect on DNA repair in the in vivo experiments. These two substances showed also a small reduction in poly(ADP-ribose) synthesis (PAR synthesis). 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) in combination with UV irradiation showed that 5-MOP was more toxic than mutagen, but induced much less DNA crosslinks than 8-MOP. Autoradiographic studies of radiation sensitization by biological agents showed significant inhibition of UDS in Yoshida tumor cells after acute mycoplasma infection in rats. Nucleoid sedimentation studies showed only in the case of Yoshida tumor cells after mycoplasma infection a dramatic effect in the sedimentation behaviour. Sensitization of cells by changing chromatin structure was also studied. Benzamide, 3-NH2-benzamide, 3-Methoxybenzamide, Spermine, Theophyllin and Caffeine were tested in different concentrations on replicative DNA synthesis, UDS after UV irradiation and PAR synthesis Chinese hamster ovary cells. 5-Methoxybenzamide was the strongest sensitizer and inhibitor of the PAR synthesis, and was used in further experiments. Results of KFA Juelich on sensitization of a mamma-adenocarcinoma EO 771 on C57 B1 mice are given. Replicative DNA synthesis, DNA repair and PAR synthesis were compared in spleen cells and adenocarcinoma cells after treatment with 5-Methoxybenzamide. An inhibitory effect on UDS could be shown only in adenocarcinoma cells but not in the mice spleen cells

  7. Isoform-specific modulation of the chemical sensitivity of conserved TRPA1 channel in the major honeybee ectoparasitic mite, Tropilaelaps mercedesae.

    Science.gov (United States)

    Dong, Xiaofeng; Kashio, Makiko; Peng, Guangda; Wang, Xinyue; Tominaga, Makoto; Kadowaki, Tatsuhiko

    2016-06-01

    We identified and characterized the TRPA1 channel of Tropilaelaps mercedesae (TmTRPA1), one of two major species of honeybee ectoparasitic mite. Three TmTRPA1 isoforms with unique N-terminal sequences were activated by heat, and the isoform highly expressed in the mite's front legs, TmTRPA1b, was also activated by 27 plant-derived compounds including electrophiles. This suggests that the heat- and electrophile-dependent gating mechanisms as nocisensitive TRPA1 channel are well conserved between arthropod species. Intriguingly, one TmTRPA1 isoform, TmTRPA1a, was activated by only six compounds compared with two other isoforms, demonstrating that the N-terminal sequences are critical determinants for the chemical sensitivity. This is the first example of isoform-specific modulation of chemical sensitivity of TRPA1 channel in one species. α-terpineol showed repellent activity towards T. mercedesae in a laboratory assay and repressed T. mercedesae entry for reproduction into the brood cells with fifth instar larvae in hives. Thus, α-terpineol could be used as the potential compound to control two major honeybee ectoparasitic mites, T. mercedesae and Varroa destructor, in the apiculture industry. PMID:27307515

  8. Isoform-specific modulation of the chemical sensitivity of conserved TRPA1 channel in the major honeybee ectoparasitic mite, Tropilaelaps mercedesae

    Science.gov (United States)

    Dong, Xiaofeng; Kashio, Makiko; Peng, Guangda; Wang, Xinyue; Tominaga, Makoto

    2016-01-01

    We identified and characterized the TRPA1 channel of Tropilaelaps mercedesae (TmTRPA1), one of two major species of honeybee ectoparasitic mite. Three TmTRPA1 isoforms with unique N-terminal sequences were activated by heat, and the isoform highly expressed in the mite's front legs, TmTRPA1b, was also activated by 27 plant-derived compounds including electrophiles. This suggests that the heat- and electrophile-dependent gating mechanisms as nocisensitive TRPA1 channel are well conserved between arthropod species. Intriguingly, one TmTRPA1 isoform, TmTRPA1a, was activated by only six compounds compared with two other isoforms, demonstrating that the N-terminal sequences are critical determinants for the chemical sensitivity. This is the first example of isoform-specific modulation of chemical sensitivity of TRPA1 channel in one species. α-terpineol showed repellent activity towards T. mercedesae in a laboratory assay and repressed T. mercedesae entry for reproduction into the brood cells with fifth instar larvae in hives. Thus, α-terpineol could be used as the potential compound to control two major honeybee ectoparasitic mites, T. mercedesae and Varroa destructor, in the apiculture industry. PMID:27307515

  9. Undergraduate Laboratory Module on Skin Diffusion

    Science.gov (United States)

    Norman, James J.; Andrews, Samantha N.; Prausnitz, Mark R.

    2011-01-01

    To introduce students to an application of chemical engineering directly related to human health, we developed an experiment for the unit operations laboratory at Georgia Tech examining diffusion across cadaver skin in the context of transdermal drug delivery. In this laboratory module, students prepare mouse skin samples, set up diffusion cells…

  10. Evidence that radio-sensitive cells are central to skin-phase protective immunity in CBA/Ca mice vaccinated with radiation-attenuated cercariae of Schistosoma mansoni as well as in naive mice protected with vaccine serum

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, V.S.; McLaren, D.J. (National Inst. for Medical Research, London (UK))

    1990-02-01

    Naive CBA/Ca mice and CBA/ca mice vaccinated 4 weeks previously with radiation-attenuated cercariae of Schistosoma mansoni were subjected to 550 rad of whole body (gamma) irradiation and then challenged 3 days later with normal cercariae. The perfusion recovery data showed that this procedure reduced the primary worm burden in naive mice by 22% and the challence worm burden in vaccinated mice by 82%. Irradiation also ablated the peripheral blood leucocytes of both mouse groups by 90-100% at the time of challenge. Histological data revealed that such treatment caused a dramatic change in number, size and leucocyte composition of cutaneous inflammatory skin reactions that characterize challenged vacccinated mice and are known to entrap invading larvae; cutaneous eosinophils were preferentially abolished by this treatment. Polyvaccine mouse serum that conferred protection passively upon naive recipient mice, failed to protect naive/irradiated mice when administered by the same protocol. Distraction of macrophages by treatment of mice with silica did not affect the establishment of a primary worm burden and reduced the protection exhibited by vaccinated mice by only 16%. These data indicade that radio-sensitive cells are important to both innate and specific acquired resistance in this mouse model and that macrophages contribute only marginally to the expression of vaccine immunity. (author).

  11. Reduction of Large Detailed Chemical Kinetic Mechanisms for Autoignition Using Joint Analyses of Reaction Rates and Sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Saylam, A; Ribaucour, M; Pitz, W J; Minetti, R

    2006-11-29

    A new technique of reduction of detailed mechanisms for autoignition, which is based on two analysis methods is described. An analysis of reaction rates is coupled to an analysis of reaction sensitivity for the detection of redundant reactions. Thresholds associated with the two analyses have a great influence on the size and efficiency of the reduced mechanism. Rules of selection of the thresholds are defined. The reduction technique has been successfully applied to detailed autoignition mechanisms of two reference hydrocarbons: n-heptane and iso-octane. The efficiency of the technique and the ability of the reduced mechanisms to reproduce well the results generated by the full mechanism are discussed. A speedup of calculations by a factor of 5.9 for n-heptane mechanism and by a factor of 16.7 for iso-octane mechanism is obtained without losing accuracy of the prediction of autoignition delay times and concentrations of intermediate species.

  12. Chemical synthesis of CdS onto TiO2 nanorods for quantum dot sensitized solar cells

    Science.gov (United States)

    Pawar, Sachin A.; Patil, Dipali S.; Lokhande, Abhishek C.; Gang, Myeng Gil; Shin, Jae Cheol; Patil, Pramod S.; Kim, Jin Hyeok

    2016-08-01

    A quantum dot sensitized solar cell (QDSSC) is fabricated using hydrothermally grown TiO2 nanorods and successive ionic layer adsorption and reaction (SILAR) deposited CdS. Surface morphology of the TiO2 films coated with different SILAR cycles of CdS is examined by Scanning Electron Microscopy which revealed aggregated CdS QDs coverage grow on increasing onto the TiO2 nanorods with respect to cycle number. Under AM 1.5G illumination, we found the TiO2/CdS QDSSC photoelectrode shows a power conversion efficiency of 1.75%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 4.04 mA/cm2 which is higher than that of a bare TiO2 nanorods array.

  13. Skin Keratins.

    Science.gov (United States)

    Wang, Fengrong; Zieman, Abigail; Coulombe, Pierre A

    2016-01-01

    Keratins comprise the type I and type II intermediate filament-forming proteins and occur primarily in epithelial cells. They are encoded by 54 evolutionarily conserved genes (28 type I, 26 type II) and regulated in a pairwise and tissue type-, differentiation-, and context-dependent manner. Keratins serve multiple homeostatic and stress-enhanced mechanical and nonmechanical functions in epithelia, including the maintenance of cellular integrity, regulation of cell growth and migration, and protection from apoptosis. These functions are tightly regulated by posttranslational modifications as well as keratin-associated proteins. Genetically determined alterations in keratin-coding sequences underlie highly penetrant and rare disorders whose pathophysiology reflects cell fragility and/or altered tissue homeostasis. Moreover, keratin mutation or misregulation represents risk factors or genetic modifiers for several acute and chronic diseases. This chapter focuses on keratins that are expressed in skin epithelia, and details a number of basic protocols and assays that have proven useful for analyses being carried out in skin.

  14. Chemical and structural analysis of solvothermal synthesized tungsten oxide nanotube without template and its hydrogen sensitive property

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Taisheng; Zhang, Yue, E-mail: zhangy@buaa.edu.cn; Li, Chen

    2014-01-25

    Graphical abstract: Imaged models of formation of nanotube during crystal growth: (a) precursor react with each other; (b) the crystal plane bended as crystallization; (c) the nanotube formed finally. Highlights: • The WO{sub 3} naonotube was prepared by solvothermal method without any addition. • The steric effect and the nucleation and growth mechanism resulted in the nanotube. • The nanotube film surface showed high oxygen vacancies. • The nanotube film showed diffusion dominated sensitivity. -- Abstract: Tungsten oxide nanotubes were synthesized by solvothermal process without template. The steric effect and the concentration of WCl{sub 6} are the dominant factors for the formation mechanism of the nanotube. The steric effect was experimentally and systematically studied with solvents including ethanol, isopropanol, n-propanol and butylalcohol, which have different molecular configuration and length, while the effect of concentration was investigated by characterizing the nanostructured productions. The samples have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The surface chemistry of the nanotube is characterized by X-ray photoelectron spectroscopy (XPS). The results indicated that the solvents species and WCl{sub 6} concentration obviously diversified the morphologies of the products; the nanotubes synthesized with isopropanol composed of W{sub 18}O{sub 49} phase; the crystal defects (O atom vacancy) formed during rapid crystallization could be modified by heat treatment. The DC electrical response of the nanotube thin film to hydrogen was measured the temperature range from 200 °C to 300 °C, which indicated a decline in electrical resistance with good sensitivity, and showed the mechanism that the reaction limited process works at low temperature, whereas the diffusion limited process works at higher temperature.

  15. Modelling the exposure to chemicals for risk assessment: a comprehensive library of multimedia and PBPK models for integration, prediction, uncertainty and sensitivity analysis - the MERLIN-Expo tool.

    Science.gov (United States)

    Ciffroy, P; Alfonso, B; Altenpohl, A; Banjac, Z; Bierkens, J; Brochot, C; Critto, A; De Wilde, T; Fait, G; Fierens, T; Garratt, J; Giubilato, E; Grange, E; Johansson, E; Radomyski, A; Reschwann, K; Suciu, N; Tanaka, T; Tediosi, A; Van Holderbeke, M; Verdonck, F

    2016-10-15

    MERLIN-Expo is a library of models that was developed in the frame of the FP7 EU project 4FUN in order to provide an integrated assessment tool for state-of-the-art exposure assessment for environment, biota and humans, allowing the detection of scientific uncertainties at each step of the exposure process. This paper describes the main features of the MERLIN-Expo tool. The main challenges in exposure modelling that MERLIN-Expo has tackled are: (i) the integration of multimedia (MM) models simulating the fate of chemicals in environmental media, and of physiologically based pharmacokinetic (PBPK) models simulating the fate of chemicals in human body. MERLIN-Expo thus allows the determination of internal effective chemical concentrations; (ii) the incorporation of a set of functionalities for uncertainty/sensitivity analysis, from screening to variance-based approaches. The availability of such tools for uncertainty and sensitivity analysis aimed to facilitate the incorporation of such issues in future decision making; (iii) the integration of human and wildlife biota targets with common fate modelling in the environment. MERLIN-Expo is composed of a library of fate models dedicated to non biological receptor media (surface waters, soils, outdoor air), biological media of concern for humans (several cultivated crops, mammals, milk, fish), as well as wildlife biota (primary producers in rivers, invertebrates, fish) and humans. These models can be linked together to create flexible scenarios relevant for both human and wildlife biota exposure. Standardized documentation for each model and training material were prepared to support an accurate use of the tool by end-users. One of the objectives of the 4FUN project was also to increase the confidence in the applicability of the MERLIN-Expo tool through targeted realistic case studies. In particular, we aimed at demonstrating the feasibility of building complex realistic exposure scenarios and the accuracy of the

  16. Contact allergy to oak moss: search for sensitizing molecules using combined bioassay-guided chemical fractionation, GC-MS, and structure-activity relationship analysis.

    Science.gov (United States)

    Bernard, Guillaume; Giménez-Arnau, Elena; Rastogi, Suresh Chandra; Heydorn, Siri; Johansen, Jeanne Duus; Menné, Torkil; Goossens, An; Andersen, Klaus; Lepoittevin, Jean-Pierre

    2003-11-01

    In addition to pure synthetic fragrance materials several natural extracts are still in use in the perfume industry. Among them oak moss absolute, prepared from the lichen Evernia prunastri (L.) Arch., is considered a major contact sensitizer and is therefore included in the fragrance mix used for diagnosing perfume allergy. The process of preparing oak moss absolute has changed during recent years and, even though several potential sensitizers have been identified from former benzene extracts, its present constituents and their allergenic status are not clear. In the study reported here, we applied a method developed for the identification of contact allergens present in natural complex mixtures to oak moss absolute. The method is based on the combination of bioassay-guided chemical fractionation, gas chromatography-mass spectrometry analysis and structure-activity relationship studies. Our first results showed that atranol and chloroatranol, formed by transesterification and decarboxylation of the lichen depsides, atranorin and chloroatranorin, during the preparation of oak moss absolute, are strong elicitants in most patients sensitized to oak moss. Methyl-beta-orcinol carboxylate, a depside degradation product and the most important monoaryl derivative of oak moss from an olfactory standpoint, was also found to elicit a reaction in most patients. PMID:13680271

  17. Consensus of classification trees for skin sensitisation hazard prediction.

    Science.gov (United States)

    Asturiol, D; Casati, S; Worth, A

    2016-10-01

    Since March 2013, it is no longer possible to market in the European Union (EU) cosmetics containing new ingredients tested on animals. Although several in silico alternatives are available and achievements have been made in the development and regulatory adoption of skin sensitisation non-animal tests, there is not yet a generally accepted approach for skin sensitisation assessment that would fully substitute the need for animal testing. The aim of this work was to build a defined approach (i.e. a predictive model based on readouts from various information sources that uses a fixed procedure for generating a prediction) for skin sensitisation hazard prediction (sensitiser/non-sensitiser) using Local Lymph Node Assay (LLNA) results as reference classifications. To derive the model, we built a dataset with high quality data from in chemico (DPRA) and in vitro (KeratinoSens™ and h-CLAT) methods, and it was complemented with predictions from several software packages. The modelling exercise showed that skin sensitisation hazard was better predicted by classification trees based on in silico predictions. The defined approach consists of a consensus of two classification trees that are based on descriptors that account for protein reactivity and structural features. The model showed an accuracy of 0.93, sensitivity of 0.98, and specificity of 0.85 for 269 chemicals. In addition, the defined approach provides a measure of confidence associated to the prediction. PMID:27458072

  18. Anyone Can Get Skin Cancer

    Science.gov (United States)

    ... Cancer Skin Cancer Screening Research Anyone Can Get Skin Cancer Order the free Anyone Can Get Skin Cancer ... true that only people with light skin get skin cancer? No. Anyone can get skin cancer. It's more ...

  19. The LINA Study: Higher Sensitivity of Infant Compared to Maternal Eosinophil/Basophil Progenitors to Indoor Chemical Exposures

    Directory of Open Access Journals (Sweden)

    Friederike Hörnig

    2016-01-01

    Full Text Available Purpose. Enhanced eosinophil/basophil (Eo/B progenitor cell levels are known to be associated with allergic inflammation and atopy risk. The aim of the present study was to investigate the influence of different indoor exposures on the recruitment and differentiation of Eo/B progenitors in mother-child pairs. Methods. In 68 mother-child pairs of the LINA study peripheral blood mononuclear cells were used to assess Eo/B colony forming units (CFUs. Information about disease outcomes and indoor exposures was obtained from questionnaires. Indoor concentrations of volatile organic compounds (VOCs were measured by passive sampling. Results. Infant’s Eo/B CFUs were positively associated with exposure to tobacco smoke, disinfectants, or VOCs. In contrast, for maternal Eo/B CFUs, only a few associations were seen. Higher numbers of infant Eo/B CFUs were observed in children with wheezing symptoms within the second year of life. Conclusions. We demonstrate that infant’s hematopoietic cells seem to respond with more sensitivity to environmental exposure compared to maternal cells. At least in infants, an activation of these hematopoietic cells by environmental exposure could contribute to an enhanced risk for the development of respiratory outcomes.

  20. Fluorescence Ratiometric Assay Strategy for Chemical Transmitter of Living Cells Using H2O2-Sensitive Conjugated Polymers.

    Science.gov (United States)

    Wang, Yunxia; Li, Shengliang; Feng, Liheng; Nie, Chenyao; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-11-01

    A new water-soluble conjugated poly(fluorene-co-phenylene) derivative (PFP-FB) modified with boronate-protected fluorescein (peroxyfluor-1) via PEG linker has been designed and synthesized. In the presence of H2O2, the peroxyfluor-1 group can transform into green fluorescent fluorescein by deprotecting the boronate protecting groups. In this case, upon selective excitation of PFP-FB backbone at 380 nm, efficient fluorescence resonance energy transfer (FRET) from PFP-FB backbone to fluorescein occurs, and accordingly, the fluorescence color of PFP-FB changes from blue to green. Furthermore, the emission color of PFP-FB and the FRET ratio change in a concentration-dependent manner. By taking advantage of PFP-FB, ratiometric detection of choline and acetylcholine (ACh) through cascade enzymatic reactions and further dynamic monitoring of the choline consumption process of cancer cells have been successfully realized. Thus, this new polymer probe promotes the development of enzymatic biosensors and provides a simpler and more effective way for detecting the chemical transmitter of living cells. PMID:26451624

  1. Fluorescence Ratiometric Assay Strategy for Chemical Transmitter of Living Cells Using H2O2-Sensitive Conjugated Polymers.

    Science.gov (United States)

    Wang, Yunxia; Li, Shengliang; Feng, Liheng; Nie, Chenyao; Liu, Libing; Lv, Fengting; Wang, Shu

    2015-11-01

    A new water-soluble conjugated poly(fluorene-co-phenylene) derivative (PFP-FB) modified with boronate-protected fluorescein (peroxyfluor-1) via PEG linker has been designed and synthesized. In the presence of H2O2, the peroxyfluor-1 group can transform into green fluorescent fluorescein by deprotecting the boronate protecting groups. In this case, upon selective excitation of PFP-FB backbone at 380 nm, efficient fluorescence resonance energy transfer (FRET) from PFP-FB backbone to fluorescein occurs, and accordingly, the fluorescence color of PFP-FB changes from blue to green. Furthermore, the emission color of PFP-FB and the FRET ratio change in a concentration-dependent manner. By taking advantage of PFP-FB, ratiometric detection of choline and acetylcholine (ACh) through cascade enzymatic reactions and further dynamic monitoring of the choline consumption process of cancer cells have been successfully realized. Thus, this new polymer probe promotes the development of enzymatic biosensors and provides a simpler and more effective way for detecting the chemical transmitter of living cells.

  2. Different pH-sensitivity patterns of 30 sodium channel inhibitors suggest chemically different pools along the access pathway.

    Directory of Open Access Journals (Sweden)

    Alexandra eLazar

    2015-09-01

    Full Text Available The major drug binding site of sodium channels is inaccessible from the extracellular side, drug molecules can only access it either from the membrane phase, or from the intracellular aqueous phase. For this reason, ligand-membrane interactions are as important determinants of inhibitor properties, as ligand-protein interactions. One way to probe this is to modify the pH of the extracellular fluid, which alters the ratio of charged vs. uncharged forms of some compounds, thereby changing their interaction with the membrane. In this electrophysiology study we used three different pH values: 6.0, 7.3 and 8.6 to test the significance of the protonation-deprotonation equilibrium in drug access and affinity. We investigated drugs of several different indications: carbamazepine, lamotrigine, phenytoin, lidocaine, bupivacaine, mexiletine, flecainide, ranolazine, riluzole, memantine, ritanserin, tolperisone, silperisone, ambroxol, haloperidol, chlorpromazine, clozapine, fluoxetine, sertraline, paroxetine, amitriptyline, imipramine, desipramine, maprotiline, nisoxetine, mianserin, mirtazapine, venlafaxine, nefazodone and trazodone. We recorded the pH-dependence of potency, reversibility, as well as onset/offset kinetics. As expected, we observed a strong correlation between the acidic dissociation constant (pKa of drugs and the pH-dependence of their potency. Unexpectedly, however, the pH-dependence of reversibility or kinetics showed diverse patterns, not simple correlation. Our data are best explained by a model where drug molecules can be trapped in at least two chemically different environments: A hydrophilic trap (which may be the aqueous cavity within the inner vestibule, which favors polar and less lipophilic compounds, and a lipophilic trap (which may be the membrane phase itself, and/or lipophilic binding sites on the channel. Rescue from the hydrophilic and lipophilic traps can be promoted by alkalic and acidic extracellular pH, respectively.

  3. Sensitivity of chemistry-transport model simulations to the duration of chemical and transport operators: a case study with GEOS-Chem v10-01

    Science.gov (United States)

    Philip, Sajeev; Martin, Randall V.; Keller, Christoph A.

    2016-05-01

    Chemistry-transport models involve considerable computational expense. Fine temporal resolution offers accuracy at the expense of computation time. Assessment is needed of the sensitivity of simulation accuracy to the duration of chemical and transport operators. We conduct a series of simulations with the GEOS-Chem chemistry-transport model at different temporal and spatial resolutions to examine the sensitivity of simulated atmospheric composition to operator duration. Subsequently, we compare the species simulated with operator durations from 10 to 60 min as typically used by global chemistry-transport models, and identify the operator durations that optimize both computational expense and simulation accuracy. We find that longer continuous transport operator duration increases concentrations of emitted species such as nitrogen oxides and carbon monoxide since a more homogeneous distribution reduces loss through chemical reactions and dry deposition. The increased concentrations of ozone precursors increase ozone production with longer transport operator duration. Longer chemical operator duration decreases sulfate and ammonium but increases nitrate due to feedbacks with in-cloud sulfur dioxide oxidation and aerosol thermodynamics. The simulation duration decreases by up to a factor of 5 from fine (5 min) to coarse (60 min) operator duration. We assess the change in simulation accuracy with resolution by comparing the root mean square difference in ground-level concentrations of nitrogen oxides, secondary inorganic aerosols, ozone and carbon monoxide with a finer temporal or spatial resolution taken as "truth". Relative simulation error for these species increases by more than a factor of 5 from the shortest (5 min) to longest (60 min) operator duration. Chemical operator duration twice that of the transport operator duration offers more simulation accuracy per unit computation. However, the relative simulation error from coarser spatial resolution generally

  4. UV Radiation and the Skin

    Directory of Open Access Journals (Sweden)

    Timothy Scott

    2013-06-01

    Full Text Available UV radiation (UV is classified as a “complete carcinogen” because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natural synthesis of vitamin D and endorphins in the skin, therefore UV has complex and mixed effects on human health. Nonetheless, excessive exposure to UV carries profound health risks, including atrophy, pigmentary changes, wrinkling and malignancy. UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma, which together affect more than a million Americans annually. Genetic factors also influence risk of UV-mediated skin disease. Polymorphisms of the melanocortin 1 receptor (MC1R gene, in particular, correlate with fairness of skin, UV sensitivity, and enhanced cancer risk. We are interested in developing UV-protective approaches based on a detailed understanding of molecular events that occur after UV exposure, focusing particularly on epidermal melanization and the role of the MC1R in genome maintenance.

  5. Pickering emulsions for skin decontamination.

    Science.gov (United States)

    Salerno, Alicia; Bolzinger, Marie-Alexandrine; Rolland, Pauline; Chevalier, Yves; Josse, Denis; Briançon, Stéphanie

    2016-08-01

    This study aimed at developing innovative systems for skin decontamination. Pickering emulsions, i.e. solid-stabilized emulsions, containing silica (S-PE) or Fuller's earth (FE-PE) were formulated. Their efficiency for skin decontamination was evaluated, in vitro, 45min after an exposure to VX, one of the most highly toxic chemical warfare agents. Pickering emulsions were compared to FE (FE-W) and silica (S-W) aqueous suspensions. PE containing an oil with a similar hydrophobicity to VX should promote its extraction. All the formulations reduced significantly the amount of VX quantified on and into the skin compared to the control. Wiping the skin surface with a pad already allowed removing more than half of VX. FE-W was the less efficient (85% of VX removed). The other formulations (FE-PE, S-PE and S-W) resulted in more than 90% of the quantity of VX removed. The charge of particles was the most influential factor. The low pH of formulations containing silica favored electrostatic interactions of VX with particles explaining the better elimination from the skin surface. Formulations containing FE had basic pH, and weak interactions with VX did not improve the skin decontamination. However, these low interactions between VX and FE promote the transfer of VX into the oil droplets in the FE-PE. PMID:27021875

  6. 75 FR 4983 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2010-02-01

    ... Register of April 24, 1990 (55 FR 17376). Consult that preamble for further information on the objectives... used as a chemical intermediate for the manufacture of a dye in imaging media/ products. Based on test..., developmental toxicity, mutagenicity, cancer, neurotoxicity, skin sensitization, hydrocarbon pneumonia,...

  7. Learning about Skin Cancer

    Science.gov (United States)

    ... Why Deadly Skin Cancers Spread 2000 News Release Learning About Skin Cancer What are the most common ... skin surface. When a melanoma becomes thick and deep, the disease often spreads to other parts of ...

  8. Skin care and incontinence

    Science.gov (United States)

    Incontinence - skin care ... or bowels (called incontinence) are at risk of skin problems around the buttocks, hips, genitals, and the ... rectum (perineum). Excess moisture in these areas makes skin problems such as redness, peeling, irritation, and yeast ...

  9. Nanocarriers for skin delivery of cosmetic antioxidants

    Directory of Open Access Journals (Sweden)

    Lucia Montenegro

    2014-08-01

    Full Text Available The demand of natural skin care products is steadily growing since consumers perceive them as safe. Currently, cosmetic manufacturers are focusing their efforts on developing innovative natural products to address skin-aging signs, thus meeting consumers’ needs of healthy appearance and well-being. To prevent or treat skin aging, topical supplementation with antioxidant is regarded as one of the most promising strategies. However, most antioxidants presently used in skin care formulations show unfavorable physicochemical properties such as excessive lipophilicity or hydrophilicity, chemical instability and poor skin penetration that actively limit their effectiveness after topical application. Therefore, nanocarriers such as liposomes, niosomes, microemulsions and nanoparticles have been widely investigated as delivery systems for antioxidants to improve their beneficial effects in the treatment of skin aging. In this article, the antioxidants most commonly used in anti-aging cosmetic products will be reviewed along with the nanocarriers designed to improve their safety and effectiveness.

  10. 78 FR 70047 - Request for the Technical Review of 25 Draft Skin Notation Assignments and Skin Notation Profiles

    Science.gov (United States)

    2013-11-22

    ... published Current Intelligence Bulletin (CIB) 61--A Strategy for Assigning New NIOSH Skin Notations . The... of multiple skin notations for distinguishing systemic (SYS), direct (DIR), and sensitizing (SEN... notation when they are identified to cause multiple effects resulting from skin exposure. For example, if...

  11. Mouse Prkar1a haploinsufficiency leads to an increase in tumors in the Trp53+/− or Rb1+/− backgrounds and chemically induced skin papillomas by dysregulation of the cell cycle and Wnt signaling

    Science.gov (United States)

    Almeida, Madson Q.; Muchow, Michael; Boikos, Sosipatros; Bauer, Andrew J.; Griffin, Kurt J.; Tsang, Kit Man; Cheadle, Chris; Watkins, Tonya; Wen, Feng; Starost, Matthew F.; Bossis, Ioannis; Nesterova, Maria; Stratakis, Constantine A.

    2010-01-01

    PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a syndrome associated with skin, endocrine and other tumors. The CNC phenotype is not easily explained by the ubiquitous cAMP signaling defect; furthermore, Prkar1a+/− mice did not develop skin and other CNC tumors. To identify whether a Prkar1a defect is truly a generic but weak tumorigenic signal that depends on tissue-specific or other factors, we investigated Prkar1a+/− mice when bred within the Rb1+/− or Trp53+/− backgrounds, or treated with a two-step skin carcinogenesis protocol. Prkar1a+/− Trp53+/− mice developed more sarcomas than Trp53+/− mice (P < 0.05) and Prkar1a+/− Rb1+/− mice grew more (and larger) pituitary and thyroid tumors than Rb1+/− mice. All mice with double heterozygosity had significantly reduced life-spans compared with their single-heterozygous counterparts. Prkar1a+/− mice also developed more papillomas than wild-type animals. A whole-genome transcriptome profiling of tumors produced by all three models identified Wnt signaling as the main pathway activated by abnormal cAMP signaling, along with cell cycle abnormalities; all changes were confirmed by qRT–PCR array and immunohistochemistry. siRNA down-regulation of Ctnnb1, E2f1 or Cdk4 inhibited proliferation of human adrenal cells bearing a PRKAR1A-inactivating mutation and Prkar1a+/− mouse embryonic fibroblasts and arrested both cell lines at the G0/G1 phase of the cell cycle. In conclusion, Prkar1a haploinsufficiency is a relatively weak tumorigenic signal that can act synergistically with other tumor suppressor gene defects or chemicals to induce tumors, mostly through Wnt-signaling activation and cell cycle dysregulation, consistent with studies in human neoplasms carrying PRKAR1A defects. PMID:20080939

  12. Elucidation of xenobiotic metabolism pathways in human skin and human skin models by proteomic profiling.

    Directory of Open Access Journals (Sweden)

    Sven van Eijl

    Full Text Available BACKGROUND: Human skin has the capacity to metabolise foreign chemicals (xenobiotics, but knowledge of the various enzymes involved is incomplete. A broad-based unbiased proteomics approach was used to describe the profile of xenobiotic metabolising enzymes present in human skin and hence indicate principal routes of metabolism of xenobiotic compounds. Several in vitro models of human skin have been developed for the purpose of safety assessment of chemicals. The suitability of these epidermal models for studies involving biotransformation was assessed by comparing their profiles of xenobiotic metabolising enzymes with those of human skin. METHODOLOGY/PRINCIPAL FINDINGS: Label-free proteomic analysis of whole human skin (10 donors was applied and analysed using custom-built PROTSIFT software. The results showed the presence of enzymes with a capacity for the metabolism of alcohols through dehydrogenation, aldehydes through dehydrogenation and oxidation, amines through oxidation, carbonyls through reduction, epoxides and carboxylesters through hydrolysis and, of many compounds, by conjugation to glutathione. Whereas protein levels of these enzymes in skin were mostly just 4-10 fold lower than those in liver and sufficient to support metabolism, the levels of cytochrome P450 enzymes were at least 300-fold lower indicating they play no significant role. Four epidermal models of human skin had profiles very similar to one another and these overlapped substantially with that of whole skin. CONCLUSIONS/SIGNIFICANCE: The proteomics profiling approach was successful in producing a comprehensive analysis of the biotransformation characteristics of whole human skin and various in vitro skin models. The results show that skin contains a range of defined enzymes capable of metabolising different classes of chemicals. The degree of similarity of the profiles of the in vitro models indicates their suitability for epidermal toxicity testing. Overall, these

  13. Pentafluorobenzyl esterification of haloacetic acids in tap water for simple and sensitive analysis by gas chromatography/mass spectrometry with negative chemical ionization.

    Science.gov (United States)

    Zhao, Can; Fujii, Yukiko; Yan, Junxia; Harada, Kouji H; Koizumi, Akio

    2015-01-01

    Chlorine is the most widely used disinfectant for control of waterborne diseases in drinking water treatment. It can react with natural organic matter in water and form haloacetic acids (HAAs). For analysis of HAA levels, derivatization with diazomethane is commonly recommended as the standard methodology in Japan. However, diazomethane is a carcinogenic alkylating agent. Therefore, in this study, a safe, simple, and sensitive quantification method was developed to monitor HAAs in drinking water. Pentafluorobenzyl esterification was used for pretreatment. The pentafluorobenzyl-ester derivative was detected by gas chromatography-negative ion chemical ionization-mass spectrometry analysis with very high sensitivity for HAAs analysis. The method has low detection limits (8-94 ng L(-1)) and good recovery rates (89-99%) for HAAs. The method was applied to 30 tap water samples from 15 cities in the Kansai region of Japan. The levels of HAAs detected were in the range 0.54-7.83 μg L(-1). Dichloroacetic acid, trichloroacetic acid, and bromochloroacetic acid were the major HAAs detected in most of the tap water, and accounted for 29%, 20% and 19% of the total HAAs, respectively. This method could be used for routine monitoring of HAAs in drinking water without exposure of workers to occupational hazards.

  14. The effect of bulking agents on the chemical stability of acid-sensitive compounds in freeze-dried formulations: sucrose inversion study.

    Science.gov (United States)

    Lu, Enxian; Ewing, Susan; Gatlin, Larry; Suryanarayanan, Raj; Shalaev, Evgenyi

    2009-09-01

    The goal of the study was to evaluate the impact of amorphous bulking agents on the chemical stability of freeze-dried materials. Polyvinylpyrrolidone and dextran of different molecular weights and lactose were used as bulking agents, and sucrose was used as an example of an acid-sensitive compound. Lyophiles containing bulking agent and sucrose at 10:1 (w/w) ratio, citrate buffer, and optionally bromophenol blue (pH indicator) were tested by X-ray powder diffractometry, differential scanning calorimetry, and Karl Fischer titrimetry. Diffuse reflectance UV-vis spectroscopy was used to obtain the concentration ratio of the deprotonated (In(2-)) to the protonated (HIn(-)) indicator species, from which the Hammett acidity function (H(2-)) was calculated. The extent of sucrose inversion in lyophiles stored at 60 degrees C was quantified by HPLC. The bulking agent had a major impact on both the apparent solid-state acidity (H(2-)) and the degradation rate, with the degradation rate constants value highest for dextran lyophiles (most "acidic", lower H(2-)) followed by lactose and polyvinylpyrrolidone lyophile (least "acidic", higher H(2-)). The Hammett acidity function can be used as an empirical solid-state acidity scale, to predict the rank-order stability of acid-sensitive compounds in lyophiles prepared with different bulking agents. PMID:19544366

  15. Chemical modification of chitosan with pH-sensitive molecules and specific ligands for efficient DNA transfection and siRNA silencing.

    Science.gov (United States)

    Singh, Bijay; Choi, Yun-Jaie; Park, In-Kyu; Akaike, Toshihiro; Cho, Chong-Su

    2014-01-01

    Successful gene therapy depends on the development of efficient and cell-specific gene delivery systems. Currently, animal viral vectors have been mostly used for in vivo and in clinical trials owing to their high transduction efficiency. However, they suffer from numerous limitations such as biosafety, immunogenicity, gene packaging capacity, complicated production and cell specificity. Therefore non-viral vectors are attractive alternatives to viral gene delivery systems due to their low toxicity, relatively easy production and greater diversity. Among non-viral vectors, chitosan and chitosan derivatives have been extensively utilized as gene carriers owing to their low immunogenicity, biocompatibility, biodegradability, low toxicity and ease of chemical modifications. However, low transfection efficiency of DNA (or low gene silencing of siRNA) and low cell specificity of chitosan should be overcome before clinical trials. The objective of this review is to summarize several parameters affecting the transfection efficiency of DNA (or gene silencing of siRNA) for the promising use of chitosan as gene carriers. Besides, chemical modifications of chitosan with pH-sensitive molecules and specific ligands so as to enhance the transfection efficiency of DNA (or gene silencing of siRNA) and cell specificity will be covered. PMID:24730283

  16. Fractional enrichment of proteins using [2-{sup 13}C]-glycerol as the carbon source facilitates measurement of excited state {sup 13}Cα chemical shifts with improved sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Ahlner, Alexandra; Andresen, Cecilia; Khan, Shahid N. [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden); Kay, Lewis E. [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry, One King’s College Circle (Canada); Lundström, Patrik, E-mail: patlu@ifm.liu.se [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden)

    2015-07-15

    A selective isotope labeling scheme based on the utilization of [2-{sup 13}C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state {sup 13}Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-{sup 13}C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state {sup 13}Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s{sup −1}, despite the small fraction of {sup 13}Cα–{sup 13}Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using {sup 13}Cα spin probes.

  17. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    Science.gov (United States)

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-03-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations.

  18. Respiratory and skin health among glass microfiber production workers: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Jaakkola Maritta S

    2009-08-01

    Full Text Available Abstract Background Only a few studies have investigated non-malignant respiratory effects of glass microfibers and these have provided inconsistent results. Our objective was to assess the effects of exposure to glass microfibers on respiratory and skin symptoms, asthma and lung function. Methods A cross-sectional study of 102 workers from a microfiber factory (response rate 100% and 76 office workers (73% from four factories in Thailand was conducted. They answered a questionnaire on respiratory health, occupational exposures, and lifestyle factors, and performed spirometry. Measurements of respirable dust were available from 2004 and 2005. Results Workers exposed to glass microfibers experienced increased risk of cough (adjusted OR 2.04, wheezing (adjOR 2.20, breathlessness (adjOR 4.46, nasal (adjOR 2.13 and skin symptoms (adjOR 3.89 and ever asthma (adjOR 3.51, the risks of breathlessness (95%CI 1.68–11.86 and skin symptoms (1.70–8.90 remaining statistically significant after adjustment for confounders. There was an exposure-response relation between the risk of breathlessness and skin symptoms and increasing level of microfiber exposure. Workers exposed to sensitizing chemicals, including phenol-formaldehyde resin, experienced increased risk of cough (3.43, 1.20–9.87 and nasal symptoms (3.07, 1.05–9.00. Conclusion This study provides evidence that exposure to glass microfibers increases the risk of respiratory and skin symptoms, and has an exposure-response relation with breathlessness and skin symptoms. Exposure to sensitizing chemicals increased the risk of cough and nasal symptoms. The results suggest that occupational exposure to glass microfibers is related to non-malignant adverse health effects, and that implementing exposure control measures in these industries could protect the health of employees.

  19. Responsive corneosurfametry following in vivo skin preconditioning.

    Science.gov (United States)

    Uhoda, E; Goffin, V; Pierard, G E

    2003-12-01

    Skin is subjected to many environmental threats, some of which altering the structure and function of the stratum corneum. Among them, surfactants are recognized factors that may influence irritant contact dermatitis. The present study was conducted to compare the variations in skin capacitance and corneosurfametry (CSM) reactivity before and after skin exposure to repeated subclinical injuries by 2 hand dishwashing liquids. A forearm immersion test was performed on 30 healthy volunteers. 2 daily soak sessions were performed for 5 days. At inclusion and the day following the last soak session, skin capacitance was measured and cyanoacrylate skin-surface strippings were harvested. The latter specimens were used for the ex vivo microwave CSM. Both types of assessments clearly differentiated the 2 hand dishwashing liquids. The forearm immersion test allowed the discriminant sensitivity of CSM to increase. Intact skin capacitance did not predict CSM data. By contrast, a significant correlation was found between the post-test conductance and the corresponding CSM data. In conclusion, a forearm immersion test under realistic conditions can discriminate the irritation potential between surfactant-based products by measuring skin conductance and performing CSM. In vivo skin preconditioning by surfactants increases CSM sensitivity to the same surfactants.

  20. Self-Powered Analogue Smart Skin.

    Science.gov (United States)

    Shi, Mayue; Zhang, Jinxin; Chen, Haotian; Han, Mengdi; Shankaregowda, Smitha A; Su, Zongming; Meng, Bo; Cheng, Xiaoliang; Zhang, Haixia

    2016-04-26

    The progress of smart skin technology presents unprecedented opportunities for artificial intelligence. Resolution enhancement and energy conservation are critical to improve the perception and standby time of robots. Here, we present a self-powered analogue smart skin for detecting contact location and velocity of the object, based on a single-electrode contact electrification effect and planar electrostatic induction. Using an analogue localizing method, the resolution of this two-dimensional smart skin can be achieved at 1.9 mm with only four terminals, which notably decreases the terminal number of smart skins. The sensitivity of this smart skin is remarkable, which can even perceive the perturbation of a honey bee. Meanwhile, benefiting from the triboelectric mechanism, extra power supply is unnecessary for this smart skin. Therefore, it solves the problems of batteries and connecting wires for smart skins. With microstructured poly(dimethylsiloxane) films and silver nanowire electrodes, it can be covered on the skin with transparency, flexibility, and high sensitivity. PMID:27010713