RESUMEN
Diabetes mellitus is clinically defined by chronic hyperglycemia. Sex differences in the presentation and outcome of diabetes exist with premenopausal women having a reduced risk of developing diabetes, relative to men, or women after menopause. Accumulating evidence shows a protective role of estrogens, specifically 17-beta estradiol, in the maintenance of pancreatic beta cell health; however, the mechanisms underlying this protection are still unknown. To elucidate these potential mechanisms, we used a pancreatic beta cell line (BTC6) and a mouse model of hyperglycemia-induced atherosclerosis, the ApoE-/-:Ins2+/Akita mouse, exhibiting sexual dimorphism in glucose regulation. In this study we hypothesize that 17-beta estradiol protects pancreatic beta cells by modulating the unfolded protein response (UPR) in response to endoplasmic reticulum (ER) stress. We observed that ovariectomized female and male ApoE-/-:Ins2+/Akita mice show significantly increased expression of apoptotic UPR markers. Sham operated female and ovariectomized female ApoE-/-:Ins2+/Akita mice supplemented with exogenous 17-beta estradiol increased the expression of adaptive UPR markers compared to non-supplemented ovariectomized female ApoE-/-:Ins2+/Akita mice. These findings were consistent to what was observed in cultured BTC6 cells, suggesting that 17-beta estradiol may protect pancreatic beta cells by repressing the apoptotic UPR and enhancing the adaptive UPR activation in response to pancreatic ER stress.
Asunto(s)
Diabetes Mellitus , Hiperglucemia , Células Secretoras de Insulina , Humanos , Femenino , Ratones , Masculino , Animales , Células Secretoras de Insulina/metabolismo , Estradiol/farmacología , Estradiol/metabolismo , Respuesta de Proteína Desplegada , Diabetes Mellitus/metabolismo , Estrés del Retículo Endoplásmico , Hiperglucemia/metabolismo , Apolipoproteínas E/metabolismoRESUMEN
BACKGROUND: Effective learning strategies are crucial to the development of academic skills and information retention, especially in post secondary education where increasingly complex subjects are explored. Active recall-based strategies have been identified as particularly effective for long-term learning. This systematic review investigates the effectiveness of various active recall-based learning strategies for improving academic performance and self-efficacy in higher education students. METHODS: A systematic review of peer-reviewed articles was conducted with a priori criteria by searching PubMed, ScienceDirect, JSTOR, PsycInfo, and Web of Science databases. Search results were screened/extracted and reconciled by two independent authors with the use of a piloted screening tool. Included studies were assessed for quality and risk of bias using the GRADE Quality Assessment Tool for Quantitative Studies. Three overarching study strategies were extracted for further investigation including flashcards, practice testing or retrieval practice, and concept mapping. Within each category, three additional unique search strings were searched, screened, and extracted. A qualitative analysis of the studies was provided. RESULTS: Among the appraised articles, flashcards were found to be popular and correlated with higher GPA and test scores. Self-testing, retrieval practice, and concept mapping were also effective but under-utilized. Concept mapping was found to boost student confidence. CONCLUSION: Active recall strategies exhibit promise for effective learning and additional research in these developing field can support academic pursuits.