RESUMEN
Social media use is consistently associated with more negative body image, but much of this literature is cross-sectional and/or lacks ecological validity. To overcome these limitations, we examined associations between everyday social media engagement and appearance satisfaction using an experience sampling method. Fifty participants from Central Europe completed a 14-day experience sampling phase in which they reported their appearance satisfaction at two random time-points each day, as well as following active engagement with social media content, using a wrist-worn wearable and a physical analogue scale (PAS; i.e., angle of a participant's forearm between flat and fully upright as a continuous response scale). Results indicated that engagement with social media content was significantly associated with lower appearance satisfaction. Additionally, we found that engagement with the content of known others was associated with significantly lower appearance satisfaction than engagement with the content of unknown others. These effects were stable even after controlling for participant demographics, active vs. passive daily social media use, and body image-related factors. These results provide evidence that everyday social media engagement is associated with lower appearance satisfaction and additionally provides preliminary support for the use of a PAS in body image research using an experience sampling method.
Asunto(s)
Medios de Comunicación Sociales , Dispositivos Electrónicos Vestibles , Humanos , Imagen Corporal/psicología , Evaluación Ecológica Momentánea , Muñeca , Estudios Transversales , Satisfacción PersonalRESUMEN
Alginate, a biocompatible polymer naturally derived from algae, is widely used as a synthetic analogue of the extracellular matrix in tissue engineering. Integrin-binding peptide motifs, including RGD, a derivative of fibronectin, are typically grafted to the alginate polymer through carbodiimide reactions between peptide amines and alginate uronic acids. However, lack of chemo-selectivity of carbodiimide reactions can lead to side reactions that lower peptide bioactivity. To overcome these limitations, we developed an approach for copper-free, strain-promoted azide-alkyne cycloaddition (SPAAC)-mediated conjugation of azide-modified adhesive peptides (azido-cyclo-RGD, Az-cRGD) onto alginate. Successful conjugation of azide-reactive cyclooctynes onto alginates using a heterobifunctional crosslinker was confirmed by azido-coumarin fluorescent assay, NMR, and through click reactions with azide-modified fluorescent probes. Compared to cyclo-RGD peptides directly conjugated to alginate polymers with standard carbodiimide chemistry, Az-cyclo-RGD peptides exhibited higher bioactivity, as demonstrated by cell adhesion and proliferation assays. Finally, Az-cRGD peptides enhanced the effects of recombinant bone morphogenetic proteins on inducing osteogenesis of osteoblasts and bone marrow stromal stem cells in 3D alginate gels. SPAAC-mediated click approaches for peptide-alginate bioconjugation overcome the limitations of previous alginate bioconjugation approaches and potentially expand the range of ligands that can be grafted to alginate polymers for tissue engineering applications.
Asunto(s)
Alginatos/síntesis química , Hidrogeles/síntesis química , Péptidos Cíclicos/síntesis química , Alginatos/farmacología , Alquinos/química , Animales , Azidas/química , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Química Clic , Reacción de Cicloadición , Hidrogeles/farmacología , Células Madre Mesenquimatosas/efectos de los fármacos , Ratones , Osteoblastos/efectos de los fármacos , Osteogénesis/efectos de los fármacos , Péptidos Cíclicos/farmacologíaRESUMEN
Mesenchymal stromal cells (MSCs) have been successfully employed in clinical applications. In most studies, autologous MSCs from the bone marrow (bmMSCs) were used, and others employed autologous adipose tissue-derived stromal cells (ADSCs). Recently, clinical feasibility studies provided evidence that MSCs from human term placenta (pMSCs) can be used for homologous therapy facilitating access to regenerative cells in emergency situations, when autologous cells are not available or not suitable. We therefore investigated the expression of MSC stemness marker CD146 and the expression of neuro- and myoregenerative cytokines by human pMSCs after expansion in three different media compliant with good manufacturing protocols (GMP) in comparison to pMSCs expanded in a commercial MSC expansion media. To replace xenobiotic serum in the GMP-compliant media employed in this study, either human serum, human serum plus platelet lysate (PLL), or human plasma plus PLL was used. We report that enrichment of media with PLL accelerates pMSC proliferation but reduces the expression of the stemness marker CD146 significantly, while PLL deprivation enhanced the CD146 expression. In contrast, the reduced expression of CD146 by PLL deprivation was not observed on bmMSCs. The expression of the cytokines investigated was not modulated significantly by PLL. We conclude that accelerated expansion of pMSCs in GMP-compliant media enriched by PLL reduces the expression of stemness marker CD146, but does not influence the expression of neuro- and myoregenerative cytokines.
RESUMEN
BACKGROUND/AIMS: Pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been shown to inhibit growth and to induce apoptosis in human hepatocellular carcinoma (HCC) cells. However, the potential benefit of pravastatin in HCC patients has still not been characterized, which prompted us to test the efficacy of pravastatin in patients with advanced HCC. METHODS: We investigated prospectively a cohort of 183 HCC patients who had been selected for palliative treatment by transarterial chemoembolization (TACE). Fifty-two patients received TACE combined with pravastatin (20-40 mg/day) and 131 patients received chemoembolization alone. Six independent predictors of survival according to the Vienna survival model for HCC were equally distributed in both groups. RESULTS: During the observation period of up to 5 years, 31 (23.7%) out of 131 patients treated by TACE alone and 19 (36.5%) out of 52 patients treated by TACE and pravastatin survived. Median survival was significantly longer in HCC patients treated by TACE and pravastatin (20.9 months, 95% CI 15.5-26.3, p = 0.003) than in HCC patients treated by TACE alone (12.0 months, 95% CI 10.3-13.7). CONCLUSION: Combined treatment of chemoembolization and pravastatin improves survival of patients with advanced HCC in comparison to patients receiving chemoembolization alone.