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- Anderson, J. K., et al.
(författare)
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Grouping of PFAS for human health risk assessment : Findings from an independent panel of experts
- 2022
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Ingår i: Regulatory toxicology and pharmacology. - : Elsevier. - 0273-2300 .- 1096-0295. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- An expert panel was convened to provide insight and guidance on per- and polyfluoroalkyl substances (PFAS) grouping for the purposes of protecting human health from drinking water exposures, and how risks to PFAS mixtures should be assessed. These questions were addressed through multiple rounds of blind, independent responses to charge questions, and review and comments on co-panelists responses. The experts agreed that the lack of consistent interpretations of human health risk for well-studied PFAS and the lack of information for the vast majority of PFAS present significant challenges for any mixtures risk assessment approach. Most experts agreed that "all PFAS" should not be grouped together, persistence alone is not sufficient for grouping PFAS for the purposes of assessing human health risk, and that the definition of appropriate subgroups can only be defined on a case-by-case manner. Most panelists agreed that it is inappropriate to assume equal toxicity/potency across the diverse class of PFAS. A tiered approach combining multiple lines of evidence was presented as a possible viable means for addressing PFAS that lack analytical and/or toxicological studies. Most PFAS risk assessments will need to employ assumptions that are more likely to overestimate risk than to underestimate risk, given the choice of assumptions regarding dose-response model, uncertainty factors, and exposure information.
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| 2. |
- Marknell DeWitt, Åsa, 1966-
(författare)
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Use of Recombinant Allergens for Component-Resolved Diagnostics (CRD) in IgE-Mediated Allergy
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immunoglobulin E (IgE)-mediated allergy occurs when our immune system causes a reaction to otherwise harmless substances (allergens). Allergens are predominantly proteins present in biological materials such as pollens, mites, animal epithelia, moulds and foods. In vitro tests for specific IgE antibodies usually employ an allergen source extract as an antibody capturing reagent. The proportion of allergenic molecules in these biochemically complex extracts may vary.Recombinant allergens may be obtained in large quantities with biotechnological techniques. These proteins can be characterized biochemically and immunologically, resulting in tests with minimal batch-to-batch variation. This thesis describes different uses of recombinant allergens in component-resolved diagnostics (CRD).In CRD, single allergenic proteins are used to establish a sensitization profile of the patient. Two timothy grass (Phleum pratense) pollen allergens, Phl p 11 and Phl p 4, were cloned and expressed as recombinant proteins. They were subsequently characterized and can, for example, be used in a panel for grass pollen CRD.Single allergens may be useful as diagnostic markers for allergic sensitization. This phenomenon was studied using tropomyosin, a major allergen from the shrimp Penaeus aztecus (Pen a 1). The characteristics of the recombinant and natural proteins were compared. The recombinant tropomyosin was then extensively tested using specific competition for IgE binding against extracts of other crustacean species, house dust mite and cockroach.In cases when an important allergen is missing or underrepresented in a natural extract, the corresponding recombinant allergen may be added to the extract as a spiking reagent. Previous studies have shown that latex extracts for diagnostic testing may lack the allergen Hev b 5. Recombinant Hev b 5 was expressed from a synthetic gene construct, incorporating several adaptations to enable efficient large scale production of the recombinant protein, to be used as a spiking reagent.
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