424 research outputs found

    The role of the narrator in narrative inquiry in education: construction and co-construction in two case studies

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    This paper explores narratives as an effective means of capturing multiple identities of research participants in complex social environments in education research. In doing so, it explores the role of the narrator in two case studies in two modes of narrative inquiry. Both studies present narratives of young people, focusing on multiple identities which are influenced by a variety of cultural and sub-cultural contexts which the participants inhabit to varying degrees. In the first case study, the researcher is the narrator; in the second, it is the research participants. The paper uses the two case studies to discuss three challenging areas in narrative research: participant voice, contextual complexities and researcher positionality and how the researcher responds to these challenges through construction and co-construction of the narratives. The authors share their strategies for addressing these three challenges in relation to the role of the narrator

    The relationship of exposure to news media with attachment to the national ethos

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    This study tested the assumption that national media played an important role in promoting a strong national ethos among Malaysians. As youth are heavy consumer of media and play important roles in further progressing the country economically and politically, it is very pertinent to examine the strength of the national ethos among the Malaysian youth of various ethnic groups, and the relationship between the exposure to the news media and strength of their national ethos. A total of 606 students from ten universities and colleges aged between 18 to 27 years were interviewed in a national survey using a self-administered questionnaire. Three dimensions of the national ethos emerged from the data and the students had positive perceptions toward selected characteristics of the country. However, there is a significant difference among the three ethnic groups in their degree of attachment to the three different dimensions of the national ethos. An overall exposure to the news media has a positive and significant relationship with the shared identity and future dimension, and shared history and values dimension of the national ethos

    Malonyl-CoA Mediates Leptin Hypothalamic Control of Feeding Independent of Inhibition of CPT-1a

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    Hypothalamic fatty acid metabolism is involved in central nervous system controls of feeding and energy balance. Malonyl-CoA, an intermediate of fatty acid biosynthesis, is emerging as a significant player in these processes. Notably, hypothalamic malonyl-CoA has been implicated in leptin's feeding effect. Leptin treatment increases malonyl-CoA level in the hypothalamic arcuate nucleus (Arc), and this increase is required for leptin-induced decrease in food intake. However, the intracellular downstream mediators of malonyl-CoA's feeding effect have not been identified. A primary biochemical action of malonyl-CoA is the inhibition of the acyltransferase activity of carnitine palmitoyltransferase-1 (CPT-1). In the hypothalamus, the predominant isoform of CPT-1 that possesses the acyltransferase activity is CPT-1 liver type (CPT-1a). To address the role of CPT-1a in malonyl-CoA's anorectic action, we used a recombinant adenovirus expressing a mutant CPT-1a that is insensitive to malonyl-CoA inhibition. We show that Arc overexpression of the mutant CPT-1a blocked the malonyl-CoA-mediated inhibition of CPT-1 activity. However, the overexpression of this mutant did not affect the anorectic actions of leptin or central cerulenin for which an increase in Arc malonyl-CoA level is also required. Thus, CPT-1a does not appear to be involved in the malonyl-CoA's anorectic actions induced by leptin. Furthermore, long-chain fatty acyl-CoAs, substrates of CPT-1a, dissociate from malonyl-CoA's actions in the Arc under different feeding states. Together, our results suggest that Arc intracellular mechanisms of malonyl-CoA's anorectic actions induced by leptin are independent of CPT-1a. The data suggest that target(s), rather than CPT-1a, mediates malonyl-CoA action on feeding

    Bioavailable insulin-like growth factor-I as mediator of racial disparity in obesity-relevant breast and colorectal cancer risk among postmenopausal women

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    Bioavailable insulin-like growth factor (IGF)-I interacts with obesity and exogenous estrogen in a racial disparity in obesity-related cancer risk, yet their interconnected pathways are not fully characterized. We investigated whether circulating bioavailable IGF-I acted as a mediator of the racial disparity in obesity-related cancers such as breast and colorectal (CR) cancers and how obesity and estrogen use regulate this relationship

    Plasma NfL is associated with the APOE ε4 allele, brain imaging measurements of neurodegeneration, and lower recall memory scores in cognitively unimpaired late-middle-aged and older adults

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    BACKGROUND: Plasma neurofilament light (NfL) is an indicator of neurodegeneration and/or neuroaxonal injury in persons with Alzheimer's disease (AD) and a wide range of other neurological disorders. Here, we characterized and compared plasma NfL concentrations in cognitively unimpaired (CU) late-middle-aged and older adults with two, one, or no copies of the APOE ε4 allele, the major genetic risk factor for AD. We then assessed plasma NfL associations with brain imaging measurements of AD-related neurodegeneration (hippocampal atrophy and a hypometabolic convergence index [HCI]), brain imaging measurements of amyloid-β plaque burden, tau tangle burden and white matter hyperintensity volume (WMHV), and delayed and total recall memory scores. METHODS: Plasma NfL concentrations were measured in 543 CU 69 ± 9 year-old participants in the Arizona APOE Cohort Study, including 66 APOE ε4 homozygotes (HM), 165 heterozygotes (HT), and 312 non-carriers (NC). Robust regression models were used to characterize plasma NfL associations with APOE ε4 allelic dose before and after adjustment for age, sex, and education. They were also used to characterize plasma NfL associations with MRI-based hippocampal volume and WMHV measurements, an FDG PET-based HCI, mean cortical PiB PET measurements of amyloid-β plaque burden and meta-region-of-interest (meta-ROI) flortaucipir PET measurements of tau tangle burden, and Auditory Verbal Learning Test (AVLT) Delayed and Total Recall Memory scores. RESULTS: After the adjustments noted above, plasma NfL levels were significantly greater in APOE ε4 homozygotes and heterozygotes than non-carriers and significantly associated with smaller hippocampal volumes (r =  - 0.43), greater tangle burden in the entorhinal cortex and inferior temporal lobes (r = 0.49, r = 0.52, respectively), and lower delayed (r =  - 0.27), and total (r =  - 0.27) recall memory scores (p < 0.001). NfL levels were not significantly associated with PET measurements of amyloid-β plaque or total tangle burden. CONCLUSIONS: Plasma NfL concentrations are associated with the APOE ε4 allele, brain imaging biomarkers of neurodegeneration, and less good recall memory in CU late-middle-aged and older adults, supporting its value as an indicator of neurodegeneration in the preclinical study of AD

    Chemosensitivity of IDH1-Mutated Gliomas Due to an Impairment in PARP1-Mediated DNA Repair

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    Mutations in isocitrate dehydrogenase (IDH) are the most prevalent genetic abnormalities in lower grade gliomas. The presence of these mutations in glioma is prognostic for better clinical outcomes with longer patient survival. In the present study, we found that defects in oxidative metabolism and 2-HG production confer chemosensitization in IDH1-mutated glioma cells. In addition, temozolomide (TMZ) treatment induced greater DNA damage and apoptotic changes in mutant glioma cells. The PARP1-associated DNA repair pathway was extensively compromised in mutant cells due to decreased NAD+ availability. Targeting the PARP DNA repair pathway extensively sensitized IDH1-mutated glioma cells to TMZ. Our findings demonstrate a novel molecular mechanism that defines chemosensitivity in IDH-mutated gliomas. Targeting PARP-associated DNA repair may represent a novel therapeutic strategy for gliomas

    Reproductive function and outcomes in female survivors of childhood, adolescent and young adult cancer: a review

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    Some survivors of childhood, adolescent, and young adult cancer are at increased risk of gonadal dysfunction and adverse pregnancy outcomes. We reviewed currently available literature that evaluated reproductive function and pregnancy outcomes of female cancer survivors diagnosed before the age of 25 years. High-dose alkylating agent chemotherapy and abdominal/pelvic radiotherapy adversely affect gonadal function in a dose-related fashion, with older age at exposure conferring greater risk as a result of the age-related decline in ovarian reserve. Gonadal injury clinically manifests as ovarian hormone insufficiency (delayed or arrested puberty, premature ovarian insufficiency, or premature menopause) and infertility. The effect of molecular-targeted agents on ovarian function has not been established. For female cancer survivors who maintain fertility, overall pregnancy (relative risk, 0.67 to 0.81) and live birth rates (hazard ratio, 0.79 to 0.82) are lower than those in the general public. Pregnancy in cancer survivors also may be associated with risks to both the mother and the fetus related to miscarriage; preterm birth; and, rarely, cardiomyopathy. Women at risk for these complications require preconception assessment and counseling from both obstetricians and oncology providers. The risk for inherited genetic disease in offspring conceived after cancer treatment exposure is not increased. The optimization of reproductive outcomes and minimization of risks of pregnancy complications in survivors requires informed, risk-based assessment and monitoring

    Association of left atrial structure and function with heart failure in older adults

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    Background: Limited data exist to characterize novel measures of left atrial (LA) structure and function in older adults without prevalent heart failure (HF). Objectives: To assess reference range of LA measures, their associations with N-terminal pro-brain-natriuretic-peptide (NTproBNP) and the related risk for incident HF or death. Methods: We analyzed LA structure [LA maximal and minimal volume indexed by body surface area (LAViMax and LAViMin)] and function [LA emptying fraction, LA reservoir, conduit and contraction strain] in 4901 participants from the Atherosclerosis Risk in Communities (ARIC) study (mean age 75±5 years, 40% male and 19% black) without prevalent HF. We assessed gender-specific 10th and 90th percentile ARIC-based reference limits in 301 participants free of prevalent cardiovascular disease, and related LA measures to NTproBNP and incident HF or death (median follow-up of 5.5 years) in the whole ARIC cohort. Results: Approximately 20% of the overall population had LA abnormalities according to the ARIC-based reference limit. Each LA measure was associated with NTproBNP and, except for LAViMax, with incident HF or death after multivariable adjustment. Results were consistent in participants with normal LAViMax (p for interaction&gt;0.05). LA measures were prognostic for both incident HFpEF or death and incident HFrEF or death. When added to HF risk factors and NTproBNP (baseline C-statistics=0.74) all LA measures, except for LAViMax, significantly enhanced the prognostic accuracy. Conclusion: Novel measures of LA structure and function, but not standard assessment by LAViMax, are associated with increased risk of incident HF or death regardless of measures of LV function and NTproBNP

    Enhancing interventions for prevention-of-mother-to-child- transmission (PMTCT) of hepatitis B virus (HBV)

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    Prevention of mother to child transmission (PMTCT) of hepatitis B virus (HBV) infection is a cornerstone of interventions to support progress towards elimination goals for viral hepatitis. Current guidelines recommend maternal screening, antiviral therapy during the third trimester of high-risk pregnancies, universal and timely HBV birth-dose vaccine, and post-exposure prophylaxis with hepatitis B immunoglobulin (HBIG) for selected neonates. However, serological and molecular diagnostic testing, treatment and HBV vaccination are not consistently deployed, particularly in many high endemicity settings, and models predict that global targets for reduction in paediatric incidence will not be met by 2030. In this article, we briefly summarise the evidence for current practice and use this as a basis to discuss areas in which PMTCT implementation can potentially be enhanced. By reducing health inequities, enhancing pragmatic use of resources, filling data gaps, developing advocacy and education, and seeking consistent investment from multilateral agencies, significant advances can be made to further reduce vertical transmission events, with wide health, societal and economic benefits
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