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  • 4-July-2023

    English

    Test No. 126: Determination of the Hydrophobicity Index of Nanomaterials Through an Affinity Measurement

    This Test Guideline (TG) describes a method to determine the hydrophobicity index (Hy) of nanomaterials (NMs), through an affinity measurement. Hydrophobicity is defined as 'the association of non-polar groups or molecules in an aqueous environment which arises from the tendency of water to exclude non-polar molecules'. By measuring their binding rate to different engineered surfaces (collectors), Hy expresses the tendency of the NMs to favour the binding to a non-polar (hydrophobic) surface because of its low affinity for water. The method applies to NMs dispersed in an aqueous solution or to NM powders after their dispersions in aqueous solutions, with or without a surfactant, using a recommended protocol.
  • 4-July-2023

    English

    Test No. 496: In vitro Macromolecular Test Method for Identifying Chemicals Inducing Serious Eye Damage and Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage

    The in vitro macromolecular test method is a biochemical in vitro test method that can be used to identify chemicals (substances and mixtures) that have the potential to induce serious eye damage as well as chemicals not requiring classification for eye irritation or serious eye damage. The in vitro macromolecular test method contains a macromolecular reagent composed of a mixture of proteins, glycoproteins, carbohydrates, lipids and low molecular weight components, that when rehydrated forms a complex macromolecular matrix which mimics the highly ordered structure of the transparent cornea. Corneal opacity is described as the most important driver for classification of eye hazard. Test chemicals producing protein denaturation, unfolding and changes in conformation will lead to the disruption and disaggregation of the highly organised macromolecular reagent matrix, and produce turbidity of the macromolecular reagent. Such phenomena is quantified, by measuring the changes in light scattering (at a wavelength of 405 nm using a spectrometer), which is compared to the standard curve established in parallel by measuring the increase in OD produced by a set of calibration substances.
  • 4-July-2023

    English

    Test No. 458: Stably Transfected Human Androgen Receptor Transcriptional Activation Assay for Detection of Androgenic Agonist and Antagonist Activity of Chemicals

    This Test Guideline describes in vitro assays, which use Androgen Receptor TransActivation (ARTA) to detect Androgen Receptor Agonists and Antagonists. The ARTA assay methods are mechanistically and functionally similar test methods that provide information on the transcription and translation of a reporter gene following the binding of a chemical to the androgen receptor and subsequent transactivation. The cell lines used in these assays express AR and have been stably transfected with an AR-responsive luciferase reporter gene, and are used to identify chemicals that activate (i.e. act as agonist) or inhibit (i.e. act as antagonists) AR-dependent transcription. Some chemicals may, in a cell type-dependent manner, display both agonist and antagonist activity and are known as selective AR modulators. The AR is activated following ligand binding, after which the receptor-ligand complex binds to specific DNA responsive elements and transactivates the receptor gene, resulting in an increase cellular expression of the luciferase enzyme. The enzyme then transforms the substrate to a bioluminescent product that can be quantitatively measured with a luminometer. This Test Guideline includes ARTA assays using the AR-EcoScreenTM cell line, the AR-CALUX® cell line, and 22Rv1/MMTV_GR-KO cell line.
  • 4-July-2023

    English

    Test No. 218: Sediment-Water Chironomid Toxicity Using Spiked Sediment

    This Test Guideline is designed to assess the effects of prolonged exposure of chemicals to the sediment-dwelling larvae of the freshwater dipteran Chironomus sp. First instar chironomid larvae are exposed to at least five concentrations of the test chemical in sediment - water systems. The test substance is spiked into the sediment and first instar larvae are subsequently introduced into test beakers in which the sediment and water concentrations have been stabilised. Chironomid emergence and development rate is measured at the end of the test. The maximum exposure duration is 28 days for C. riparius, C. yoshimatsui, and 65 days for C. tentans. The limit test corresponds to one dose level of 1000 mg/kg. Larval survival and weight may also be measured after 10 days if required (using additional replicates as appropriate). The study report should include the development time and the total number of fully emerged midges (sex and number are recorded daily), the observation of any abnormal behaviour the number of visible pupae that have failed to emerge and any egg masses deposition. The data are analysed either by using a regression model in order to estimate the concentration that would cause x % reduction in emergence or larval survival or growth, or by using statistical hypothesis testing to determine a NOEC/LOEC.
  • 4-July-2023

    English

    Test No. 491: Short Time Exposure In Vitro Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage

    This Test Guideline describes a cytotoxicity-based in vitro assay that is performed on a confluent monolayer of Statens Seruminstitut Rabbit Cornea (SIRC) cells, cultured on a 96-well polycarbonate microplate. After five-minute exposure to a test chemical, the cytotoxicity is quantitatively measured as the relative viability of SIRC cells using the MTT assay. Decreased cell viability is used to predict potential adverse effects leading to ocular damage. Cell viability is assessed by the quantitative measurement, after extraction from the cells, of blue formazan salt produced by the living cells by enzymatic conversion of the vital dye MTT, also known as Thiazolyl Blue Tetrazolium Bromide. The obtained cell viability is compared to the solvent control (relative viability) and used to estimate the potential eye hazard of the test chemical. A test chemical is classified as UN GHS Category 1 when both the 5% and 0.05% concentrations result in a cell viability smaller than or equal to (≤) 70%. Conversely, a chemical is predicted as UN GHS No Category when both 5% and 0.05% concentrations result in a cell viability higher than (>) 70%.
  • 4-July-2023

    English

    Test No. 405: Acute Eye Irritation/Corrosion

    This method provides information on health hazard likely to arise from exposure to test substance (liquids, solids and aerosols) by application on the eye. This Test Guideline is intended preferably for use with albino rabbit. The test substance is applied in a single dose in the conjunctival sac of one eye of each animal. The other eye, which remains untreated, serves as a control. The initial test uses an animal; the dose level depends on the test substance nature. A confirmatory test should be made if a corrosive effect is not observed in the initial test, the irritant or negative response should be confirmed using up to two additional animals. It is recommended that it be conducted in a sequential manner in one animal at a time, rather than exposing the two additional animals simultaneously. The duration of the observation period should be sufficient to evaluate fully the magnitude and reversibility of the effects observed. The eyes should be examined at 1, 24, 48, and 72 hours after test substance application. The ocular irritation scores should be evaluated in conjunction with the nature and severity of lesions, and their reversibility or lack of reversibility. Use of topical anesthetics and systemic analgesics to avoid or minimize pain and distress in ocular safety testing procedures is described.
  • 4-July-2023

    English

    Test No. 442E: In Vitro Skin Sensitisation - In Vitro Skin Sensitisation assays addressing the Key Event on activation of dendritic cells on the Adverse Outcome Pathway for Skin Sensitisation

    The present Key Event based Test Guideline (TG) addresses the human health hazard endpoint skin sensitisation, following exposure to a test chemical. More specifically, it addresses the activation of dendritic cells, which is one Key Event on the Adverse Outcome Pathway (AOP) for Skin Sensitisation. Skin sensitisation refers to an allergic response following skin contact with the tested chemical, as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS). This TG provides three in vitro test methods addressing the same Key Event on the AOP: (i) the human cell Line Activation Test or h-CLAT method, (ii) the U937 Cell Line Activation Test or U-SENS and (iii) the Interleukin-8 Reporter Gene Assay or IL-8 Luc assay. All of them are used for supporting the discrimination between skin sensitisers and non-sensitisers in accordance with the UN GHS. Test methods described in this TG either quantify the change in the expression of cell surface marker(s) associated with the process of activation of monocytes and DC following exposure to sensitisers (e.g. CD54, CD86) or the changes in IL-8 expression, a cytokine associated with the activation of DC. In the h-CLAT and U-SENS assays, the changes of surface marker expression are measured by flow cytometry following cell staining with fluorochrome-tagged antibodies. In the IL-8 Luc assay, the changes in IL-8 expression are measured indirectly via the activity of a luciferase gene under the control of the IL-8 promoter. The relative fluorescence or luminescence intensity of the treated cells compared to solvent/vehicle control are calculated and used in the prediction model, to support the discrimination between sensitisers and non-sensitisers.
  • 4-July-2023

    English

    Environment at a Glance in Latin America and the Caribbean - Spotlight on Climate Change

    Environment at a Glance in Latin America and the Caribbean: Spotlight on Climate Change focusses on climate change, looking at trends in greenhouse gas emissions, exposure to climate-related hazards and climate policies. It provides key messages on past progress and remaining efforts to be made in Latin America and the Caribbean. The report draws on the OECD’s expertise in environmental data and indicators, on the work of the International Programme for Action on Climate (IPAC) and is part of the OECD Latin America and the Caribbean Regional Programme. The indicators presented come from OECD and other international databases, and reveal substantive gaps in the availability of data on the environment and climate in the region. This interactive report allows users to play with the data and graphics and to download and share them.
  • 30-June-2023

    English

    OECD Biotechnology Update

    Read our newsletter to stay up-to-date with all the latest OECD work on biotechnology.

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