1,210 research outputs found

    A diffusion model approach to analyzing performance on the flanker task: the role of the DLPFC

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    The anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) are involved in conflict detection and conflict resolution, respectively. Here, we investigate how lifelong bilingualism induces neuroplasticity to these structures by employing a novel analysis of behavioural performance. We correlated grey matter volume (GMV) in seniors reported by Abutalebi et al. (2015) with behavioral Flanker task performance fitted using the diffusion model (Ratcliff, 1978). As predicted, we observed significant correlations between GMV in the DLPFC and Flanker performance. However, for monolinguals the non-decision time parameter was significantly correlated with GMV in the left DLPFC, whereas for bilinguals the correlation was significant in the right DLPFC. We also found a significant correlation between age and GMV in left DLPFC and the non-decision time parameter for the conflict effect for monolinguals only. We submit that this is due to cumulative demands on cognitive control over a lifetime of bilingual language processin

    Marketing Channel Choice Decisions of Agricultural Producers using the Transaction Cost Approach: A Review

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    In the context of the development of policies and programs to improve the lives of farmers, there is a growing recognition in identifying transaction cost as a policy base for the development of agribusiness. This paper reviewed studies about the associated transaction costs incurred in relation to the distribution and channel management of agricultural produce, particularly on the decision to directly sell to the market, to enter into an agreement with an intermediary, and to become a member in a marketing cooperative. Common themes regarding the marketing channel choice decisions identified in the different studies are the following: (1) farmers who have knowledge about the price of the good in the market are more inclined to sell directly to the market; (2) farmers who trust intermediaries and the workers of marketing cooperatives are more inclined to sell their produce through intermediaries and marketing cooperatives; (3) farmers perceived an increase in their bargaining power and income risk; and (4) institutional arrangements with intermediaries and credit cooperatives require trust and proper implementation of contracts in order for such arrangements to be sustainable. Such common themes reveal that transaction costs are significant in the decision-making process of farmers in the marketing of their produce. Interventions should be undertaken in order to ensure the proper implementation of such arrangements and prevention of abuse of intermediaries and workers of marketing cooperatives

    The cAMP Signaling pathway and direct protein kinase a phosphorylation regulate polycystin-2 (TRPP2) Channel Function

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    Polycystin-2 (PC2) is aTRP-type, Ca2+-permeable non-selective cation channel that plays an important role in Ca2+ signaling in renal and non-renal cells. The effect(s) of the cAMP pathway and kinase mediated phosphorylation of PC2 seem to be relevant to PC2 trafficking and its interaction with polycystin-1. However, the role of PC2 phosphorylation in channel function is still poorly defined. Here we reconstituted apical membranes of term human syncytiotrophoblast (hST), containing endogenous PC2 (PC2hst), and in vitro translated channel protein (PC2iv). Addition of the catalytic subunit of PKA increased by 566% the spontaneous PC2hst channel activity in the presence of ATP. Interestingly, 8-Br-cAMP also stimulated spontaneous PC2hst channel activity in the absence of the exogenous kinase. Either stimulation was inhibited by addition of alkaline phosphatase, which in turn, was reversed by the phosphatase inhibitor vanadate. Neither maneuver modified the single channel conductance but instead increased channel mean open time. PKA directly phosphorylated PC2, which increased the mean open time but not the single channel conductance of the channel. PKA phosphorylation did not modify either R742X truncated or S829A-mutant PC2iv channel function. The data indicate that the cAMP pathway regulates PC2-mediated cation transport in the hST. The relevant PKA site for PC2 channel regulation centers on a single residue serine 829, in the carboxyl terminus.Fil: Cantero, Maria del Rocio. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Biofísica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Velázquez, Irina Florencia. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Biofísica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Streets, Andrew J.. University of Sheffield Medical School; Reino UnidoFil: Ong, Albert C. M.. University of Sheffield Medical School; Reino UnidoFil: Cantiello, Horacio Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Biofísica; Argentin

    A Cross-Sectional Study of People with Epilepsy and Neurocysticercosis in Tanzania: Clinical Characteristics and Diagnostic Approaches.

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    Neurocysticercosis (NCC) is a major cause of epilepsy in regions where pigs are free-ranging and hygiene is poor. Pork production is expected to increase in the next decade in sub-Saharan Africa, hence NCC will likely become more prevalent. In this study, people with epilepsy (PWE, n=212) were followed up 28.6 months after diagnosis of epilepsy. CT scans were performed, and serum and cerebrospinal fluid (CSF) of selected PWE were analysed. We compared the demographic data, clinical characteristics, and associated risk factors of PWE with and without NCC. PWE with NCC (n=35) were more likely to be older at first seizure (24.3 vs. 16.3 years, p=0.097), consumed more pork (97.1% vs. 73.6%, p=0.001), and were more often a member of the Iraqw tribe (94.3% vs. 67.8%, p=0.005) than PWE without NCC (n=177). PWE and NCC who were compliant with anti-epileptic medications had a significantly higher reduction of seizures (98.6% vs. 89.2%, p=0.046). Other characteristics such as gender, seizure frequency, compliance, past medical history, close contact with pigs, use of latrines and family history of seizures did not differ significantly between the two groups. The number of NCC lesions and active NCC lesions were significantly associated with a positive antibody result. The electroimmunotransfer blot, developed by the Centers for Disease Control and Prevention, was more sensitive than a commercial western blot, especially in PWE and cerebral calcifications. This is the first study to systematically compare the clinical characteristics of PWE due to NCC or other causes and to explore the utility of two different antibody tests for diagnosis of NCC in sub-Saharan Africa

    'Experts', 'partners' and 'fools': exploring agency in HIV treatment seeking among African migrants in London

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    In an attempt to promote patient agency and foster more egalitarian relationships between patients and doctors, discourse concerning health and wellbeing in the UK has increasingly centred around the notion of informed and 'expert' patients who are able to effectively input into the direction and management of their own health care and treatment. While the relationship between a patient and their doctor can play a vital role in influencing the treatment decisions and health-related outcomes of people living with long term illness, little is known about the ways in which people living with HIV actually perceive their relationship with their doctors, nor the implications this may have for the types of treatment they may seek to use and the related information that they share. Drawing on 11 focus group discussions and 20 repeat interviews undertaken in 2008-2009 with HIV-positive adult migrants from Zambia, Zimbabwe and South Africa living in the UK, this paper argues that patient-doctor relationships can be heavily influenced by the perceived legitimacy of different forms of medical knowledge and treatments and by culturally influenced ideas regarding health, wellbeing and agency. Despite a desire amongst some migrants to use 'traditional' medicines from southern Africa as well as other non-biomedical treatments and therapies, the research found that the perceived lack of legitimacy associated with these treatments in the UK rendered their use a largely clandestine activity. At the same time, many patients made clear distinctions concerning issues affecting their immediate health and factors influencing their more general wellbeing, which in turn, impacted upon the information that they chose to share with, or conceal from, their doctors. Such findings challenge assumptions underpinning policy promoting patient agency and have significant and, in cases, potentially adverse implications for the safety and effective administration and management of HIV treatments in African migrant populations and possibly more generally. (C) 2009 Elsevier Ltd. All rights reserved

    Changing the Treatment Paradigm for Type 2 Diabetes

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    Based on the results of the U.K. Prospective Diabetes Study (UKPDS), “… treatment of type 2 diabetes [should] include aggressive efforts to lower blood glucose levels as close to normal as possible. …” This was the recommendation the American Diabetes Association promulgated based on the results of the UKPDS when published (1). The suggestion was soon adopted by official guidelines in every region of the world (2). They are generally consistent in recommending an A1C goal of <7.0%. However, the results of the UKPDS remained inconclusive with respect to cardiovascular (CV) complications because of a risk reduction that was only close to statistical significance (−16%, P = 0.052). In support of the UKPDS results, however, a recent meta-analysis of randomized trials in type 2 diabetes (3) calculated a 19% reduction in the incidence of any type of macrovascular event associated with improved long-term glycemic control. Moreover, a strong association between glycemic control and micro- and macrovascular disease has been highlighted in type 1 diabetic patients (4,5)

    Evo-devo of human adolescence: beyond disease models of early puberty

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    Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research

    Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase

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    Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of DHFR with dissociation constants (KD)of 0.9 and 1.8 μM, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (-)-epigallocatechin (EGC) and (-)-epicatechin (EC)] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl)-(-)-epicatechin; TMECG), which effectively binds to DHFR (KD = 2.1 μM). In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a KD of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a KD of 0.6 μM. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy

    Prognostic implications of epidermal and platelet-derived growth factor receptor alterations in 2 cohorts of IDH

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    Background: Glioblastoma remains a deadly brain cancer with dismal prognosis. Genetic alterations, including IDH mutations, 1p19q co-deletion status and MGMT promoter methylation have been proven to be prognostic and predictive to response to treatment in gliomas. In this manuscript, we aimed to correlate other mutations and genetic alterations with various clinical endpoints in patients with IDH-wild-type (IDHwt) glioblastoma. Methods: We compiled a comprehensive clinically annotated database of IDHwt GBM patients treated at the Ohio State University Wexner Medical Center for whom we had mutational data through a CLIA-certified genomic laboratory. We then added data that is publicly available from Memorial Sloan Kettering Cancer Center through cBioPortal. Each of the genetic alterations (mutations, deletions, and amplifications) served as a variable in univariate and multivariate Cox proportional hazard models. Results: A total of 175 IDHwt GBM patients with available MGMT promoter methylation data from both cohorts were included in the analysis. As expected, MGMT promoter methylation was significantly associated with improved overall survival (OS). Median OS for MGMT promoter methylated and unmethylated GBM was 26.5 and 18 months, respectively (HR 0.45; P = .003). Moreover, EGFR/ERBB alterations were associated with favorable outcome (HR of 0.37 (P = .003), but only in MGMT promoter unmethylated GBM. We further found that patients with EGFR/ERBB alterations who also harbored PDGFRA amplification had a significantly worse outcome (HR 7.89; P = .025). Conclusions: Our data provide further insight into the impact of genetic alterations on various clinical outcomes in IDHwt GBM in 2 cohorts of patients with detailed clinical information and inspire new therapeutic strategies for IDHwt GBM
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