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- Bock (Seifert), Oliver, et al.
(författare)
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Studies of Transforming Growth Factors Beta 1–3 and their Receptors I and II in Fibroblast of Keloids and Hypertrophic Scars
- 2005
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555. ; 85:3, s. 216-220
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Tidskriftsartikel (refereegranskat)abstract
- Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterized by an abnormal deposition of extracellular matrix components, particularly collagen. There is uncertain evidence that transforming growth factor-beta (TGFβ) is involved in keloid formation. Therefore we investigated the expression of TGFβ1, 2 and 3 and their receptors in keloids, hypertrophic scars and normal skin. Dermal fibroblasts were obtained from punch biopsies of patients with keloids and hypertrophic scars and from normal skin of healthy individuals. Total RNA was isolated and the expression of TGFβ1, 2 and 3 and of TGFβ receptors I and II (TGFβRI and II) was analysed by real-time PCR using the Lightcycler technique. Our data demonstrate significantly lower TGFβ2 mRNA expression in hypertrophic scar fibroblasts as compared with fibroblasts derived from keloids and normal skin (p<0.05). In contrast, TGFβ3 mRNA expression was significantly lower in keloid fibroblasts in comparison with fibroblasts derived from hypertrophic scar and normal skin (p<0.01). TGFβRI mRNA expression was significantly decreased in hypertrophic scar fibroblasts (p<0.01) and TGFβRII mRNA expression was decreased in keloids compared with hypertrophic scar fibroblasts (p<0.001), The ratio of TGFβRI/TGFβRII expression was increased in keloids compared with hypertrophic scar and normal skin fibroblasts. As recently supposed, an increased TGFβRI/TGFβRII ratio could promote fibrosis. Therefore our data support a possible role of TGFβRI and TGFβRII in combination with a certain TGFβ expression pattern as fibrosis-inducing factors in keloids.
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| 2. |
- Grossmann, Igor, et al.
(författare)
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Insights into the accuracy of social scientists' forecasts of societal change
- 2023
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Ingår i: Nature Human Behaviour. - : Springer Nature. - 2397-3374. ; 7, s. 484-501
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Tidskriftsartikel (refereegranskat)abstract
- How well can social scientists predict societal change, and what processes underlie their predictions? To answer these questions, we ran two forecasting tournaments testing the accuracy of predictions of societal change in domains commonly studied in the social sciences: ideological preferences, political polarization, life satisfaction, sentiment on social media, and gender-career and racial bias. After we provided them with historical trend data on the relevant domain, social scientists submitted pre-registered monthly forecasts for a year (Tournament 1; N = 86 teams and 359 forecasts), with an opportunity to update forecasts on the basis of new data six months later (Tournament 2; N = 120 teams and 546 forecasts). Benchmarking forecasting accuracy revealed that social scientists' forecasts were on average no more accurate than those of simple statistical models (historical means, random walks or linear regressions) or the aggregate forecasts of a sample from the general public (N = 802). However, scientists were more accurate if they had scientific expertise in a prediction domain, were interdisciplinary, used simpler models and based predictions on prior data. How accurate are social scientists in predicting societal change, and what processes underlie their predictions? Grossmann et al. report the findings of two forecasting tournaments. Social scientists' forecasts were on average no more accurate than those of simple statistical models.
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| 4. |
- Yu, Haiyan, et al.
(författare)
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Decreased expression of inhibitory SMAD6 and SMAD7 in keloid scarring
- 2006
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Ingår i: Journal of Plastic, Reconstructive and Aesthetic Surgery. - : Elsevier BV. - 1748-6815. ; 59:3, s. 221-229
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Tidskriftsartikel (refereegranskat)abstract
- Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterised by an abnormal deposition of extracellular matrix components, in particular collagen. There is evidence that transforming growth factor-beta (TGFβ) is involved in keloid formation. SMAD proteins play a crucial role in TGFβ signaling and in terminating the TGFβ signal by a negative feedback loop through SMAD6 and 7. It is unclear how TGFβ signalling is connected to the pathogenesis of keloids. Therefore, we investigated the expression of SMAD mRNA and proteins in keloids, in normal skin and in normal scars. Dermal fibroblasts were obtained from punch-biopsies of keloids, normal scars and normal skin. Cells were stimulated with TGFβ1 and the expression of SMAD2, 3, 4, 6 and 7 mRNA was analysed by real time RT-PCR. Protein expression was determined by Western blot analysis. Our data demonstrate a decreased mRNA expression of the inhibitory SMAD6 and 7 in keloid fibroblasts as compared to normal scar (p<0.01) and normal skin fibroblasts (p<0.05). SMAD3 mRNA was found to be lower in keloids (p<0.01) and in normal scar fibroblasts (p<0.001) compared to normal skin fibroblasts. Our data showed for the first time a decreased expression of the inhibitory SMAD6 and SMAD7 in keloid fibroblasts. This could explain why TGFβ signaling is not terminated in keloids leading to overexpression of extracellularmatrix in keloids. These data support a possible role of SMAD6 and 7 in the pathogenesis of keloids.
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