Standard treatment for large burns is transplantation with meshed split skin autografts (SSGs). A disadvantage of this treatment is that healing is accompanied by scar formation. Application of autologous epidermal cells (keratinocytes and melanocytes) may be a suitable therapeutic alternative, since this may enhance wound closure and improve scar quality. A prospective, multicenter randomized clinical trial was performed in 40 adult patients with acute full thickness burns. On two comparable wound areas, conventional treatment with SSGs was compared to an experimental treatment consisting of SSGs in combination with cultured autologous epidermal cells (ECs) seeded in a collagen carrier. The primary outcome measure was wound closure after 5-7 days. Secondary outcomes were safety aspects and scar quality measured by graft take, scar score (POSAS), skin colorimeter (DermaSpectrometer) and elasticity (Cutometer). Wound epithelialization after 5-7 days was significantly better for the experimental treatment (71%) compared to the standard treatment (67%) (p = 0.034, Wilcoxon), whereas the take rates of the grafts were similar. No related adverse events were recorded. Scar quality was evaluated at 3 (n = 33) and 12 (n = 28) months. The POSAS of the observer after 3 and 12 months and of the patient after 12 months were significantly better for the experimental area. Improvements between 12% and 23% (p ≤ 0.010, Wilcoxon) were detected for redness, pigmentation, thickness, relief, and pliability. Melanin index at 3 and 12 months and erythema index at 12 months were closer to normal skin for the experimental treatment than for conventional treatment (p ≤ 0.025 paired samples t-test). Skin elasticity showed significantly higher elasticity (p = 0.030) in the experimental area at 3 months follow-up. We showed a safe application and significant improvements of wound healing and scar quality in burn patients after treatment with ECs versus SSGs only. The relevance of cultured autologous cells in treatment of extensive burns is supported by our current findings.
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This article gives information on an international ring trial of the epidermal-equivalent (EE) sensitizer potency assay.
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Despite changing attitudes towards animal testing and current legislation to protect experimental animals, the rate of animal experiments seems to have changed little in recent years. On May 15–16, 2013, the In Vitro Testing Industrial Platform (IVTIP) held an open meeting to discuss the state of the art in alternative methods, how companies have, can, and will need to adapt and what drives and hinders regulatory acceptance and use. Several key messages arose from the meeting. First, industry and regulatory bodies should not wait for complete suites of alternative tests to become available, but should begin working with methods available right now (e.g., mining of existing animal data to direct future studies, implementation of alternative tests wherever scientifically valid rather than continuing to rely on animal tests) in non-animal and animal integrated strategies to reduce the numbers of animals tested. Sharing of information (communication), harmonization and standardization (coordination), commitment and collaboration are all required to improve the quality and speed of validation, acceptance, and implementation of tests. Finally, we consider how alternative methods can be used in research and development before formal implementation in regulations. Here we present the conclusions on what can be done already and suggest some solutions and strategies for the future.
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Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch’s postulates for this microorganism. We term this condition D. antillarum scuticociliatosis.
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Chronic itching is a serious and uncomfortable condition. The scratch response might result in a vicious cycle of alternating itching and scratching. To develop psychological interventions for people suffering from chronic itching and to break the vicious itch-scratching-itch cycle, it is important to elucidate which environmental factors trigger itch sensations. Virtual reality (VR) techniques provide a useful tool to examine specific content characteristics in a three-dimensional (3D VR) environment and their influences on itch sensations and scratching behaviour. This article describes two experiments in which we focused on the effects of environmental information on itching and scratching behaviour. Additionally, in the second experiment, we examined the influence of having a chronic skin condition on sensitivity to itch induction. We found evidence for the importance of the content of audio–visual materials for the effectiveness in inducing feelings of itch in the observers. In both experiments, we observed significantly higher levels of perceived itch in the itch-inducing conditions than in the control condition. Moreover, the results showed that elevated levels of perceived itch were associated with an increase in scratching behaviours, which was especially salient in the contagious itch condition, in which perceived itch was accompanied by a significant increase in the number of scratches. Experiment 2 additionally showed increased perceived itch levels in participants who reported having a chronic skin condition, reflecting higher sensitivity to itch-inducing audio–visual stimuli in this group than in participants without a chronic skin condition. Based on the results we concluded that directing attention towards itch- or scratch aspects of related information in the environment and to the consequences for one’s own skin are effective tools to induce itch sensations and scratching behaviour. This knowledge provides tools for developing novel strategies in advising and treating people suffering from chronic itching and breaking the vicious itch-scratching-itch cycle.
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The worldwide rise of skin cancer incidence rates increases the need to investigate ultraviolet radiation (UVR), as it is one of the main causes of skin cancer. 1 A ’ u to UVR varies depending on different factors such as the location of the individual and shielding effects. In this analysis, we evaluated wearables at different body positions measuring ultraviolet radiation when worn during daily activities at different locations. First, we analyzed which of the body positions provide the most robust measurements. We then devised a new measure, the horizon shielding factor, to evaluate the effect of horizon shielding and explored if high/low horizon shielding factor values coincide with particular geospatial attributes.
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Multi-layer cell constructs produced in vitro are an innovative treatment option to support the growing demand for therapy in regenerative medicine. Our research introduces a novel construct integrating organ-derived decellularised extracellular matrix (dECM) hydrogels and 3D-printed biodegradable polymer meshes composed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) to support and maintain multiple layers of different cell types. We achieved that by integrating the mechanical stability of PHBV+P34HB, commonly used in the food storage industry, with a dECM hydrogel, which replicates organ stiffness and supports cellular survival and function. The construct was customised by adjusting the fibre arrangement and pore sizes, making it a suitable candidate for a personalised design. We showed that the polymer is degradable after precoating it with PHB depolymerase (PhaZ), with complete degradation achieved in 3–5 days and delayed by adding the hydrogel to 10 days, enabling tuneable degradation for regenerative medicine applications. Finally, as a proof of concept, we composed a three-layered tissue in vitro; each layer represented a different tissue type: epidermal, vascular, and subcutaneous layers. Possible future applications include wound healing and diabetic ulcer paths, personalised drug delivery systems, and personalised tissue implants.
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In het werkveld van Life Sciences & Chemistry heeft Innovative testing te maken met het testen van stoffen op hun werking en veiligheid. Met stoffen wordt hier bedoeld alle mogelijke chemicaliën waar aan we blootgesteld worden, zoals chemicaliën in onze leef- en werkomgeving, medicijnen (inclusief biologicals), maar ook stoffen in de voeding (inclusief voedselbestanddelen en natuurlijke stoffen). Mijn les zal echter voornamelijk gaan over de laatste twee categorieën, medicijnen en stoffen in de voeding. Ik wil in mijn openbare les eerst uiteenzetten waarom het zo belangrijk is om vast te stellen wat de werking en veiligheid van stoffen is. Vervolgens wil ik beschrijven welke innovaties op dit moment al plaatsvinden, in de toxicologie en de farmacologie. Dit wil ik doen om aan te geven waar de parallellen en mogelijkheden voor synergie liggen. Daarna zal ik aan de hand van een aantal voorbeelden aangeven tegen welke grenzen men zoal aanloopt bij het testen van werking en veiligheid van stoffen, om daarbij ook aan te geven dat er duidelijk aanwijzingen zijn voor het vervagen van grenzen tussen farmacologie en toxicologie. Tot slot zal ik aangeven welke rol het Kenniscentrum Life Sciences & Chemistry van Hogeschool Utrecht op het gebied van onderzoek én onderwijs in het werkveld van Innovative testing in Life Sciences & Chemistry wil gaan spelen.
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In de openbare les van mijn collega lector Raymond Pieters, is het domein van het lectoraat ‘Innovative Testing in Life Sciences & Chemistry’ toegelicht. Kort samengevat richt dit lectoraat zich op de ontwikkeling en toepassing van innovatieve teststrategieën om geneesmiddelen, voedingsmiddelen of chemicaliën (stoffen) te beoordelen op hun werkzaamheid (effectiviteit) en veiligheid. De nadruk ligt op de ontwikkeling van snelle, kosteneffectieve testmethoden die een relevante voorspelling van effecten op de gezondheid van de mens en het milieu opleveren én waarbij geen of minder proefdieren worden gebruikt. In mijn les zal ik u laten zien waar proefdieren voor gebruikt worden. Hierbij zal ik mij voornamelijk richten op de Nederlandse situatie. Ik zal ingaan op de wetenschappelijke en maatschappelijke wens om minder proefdieren te gebruiken en op de vraag wat we verstaan onder ‘alternatieven voor dierproeven’. Daarna zal ik bespreken waarom er in Nederland en Europa recentelijk meer aandacht is voor dit onderwerp. Het overzicht zal niet uitputtend zijn, maar zal u een goede indruk geven van het landschap. Ook zal ik stil staan bij de vraag: Waarom zijn we tot nog toe zo weinig succesvol geweest op het gebied van alternatieven voor dierproeven? Wat zijn de obstakels en wat kunnen we hier van leren? Hoe zouden we in de praktijk de toepassing van alternatieven kunnen stimuleren? Wat moet er beter, en hoe gaan we dat doen? Als we slimmer willen testen moeten we de huidige grenzen verleggen, of beter over de grenzen van ons vakgebied heen kijken. Ik zal aangeven waar prioriteiten liggen en hoe we de meeste ‘winst’ kunnen behalen in termen van proefdiervermindering in relatie tot productinnovatie. Tot slot zal ik aangeven welke bruggen we moeten bouwen en wat de rol is van de Hogeschool Utrecht
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