1,333 research outputs found

    Limits to tDCS effects in language:failures to modulate word production in healthy participants with frontal or temporal tDCS

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    Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms

    An adapted triage tool (ETAT) at Red Cross War Memorial Children’s Hospital Medical Emergency Unit, Cape Town: An evaluation

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    Objective. To evaluate the efficacy of an adapted Emergency Triage Assessment and Treatment (ETAT) tool at a children’s hospital. Design. A two-armed descriptive study. Setting. Red Cross War Memorial Children’s Hospital, Cape Town, South Africa. Methods. Triage data on 1 309 children from October 2007 and July 2009 were analysed. The number of children in each triage category (red (emergency), orange (urgent or priority) and green (non-urgent)) and their disposal were evaluated. Results. 1. The October 2007 series: 902 children aged 5 days - 15 years were evaluated. Their median age was 20 (interquartile range (IQR) 7 - 50) months, and 58.8% (n=530) were triaged green, 37.5% (n=338) orange and 3.8% (n=34) red. Over 90% of children in the green category were discharged (478/530), while 32.5% of children triaged orange (110/338) and 52.9% of children triaged red (18/34) were admitted. There was a significant increase in admission rate for each triage colour change from green through orange to red after adjustment for age category (risk ratio (RR) 2.6; 95% confidence interval (CI) 2.2 - 3.1). 2. The July 2009 cohort: 407 children with a median age of 22 months (IQR 7 - 53 months) were enrolled. Twelve children (2.9%) were triaged red, 187 (45.9%) orange and 208 (51.1%) green. A quarter (101/407) of the children triaged were admitted: 91.7% (11/12) from the red category and 36.9% (69/187) from the orange category were admitted, while 89.9% of children in the green category (187/208) were discharged. After adjusting for age category, admissions increased by more than 300% for every change in triage acuity (RR 3.2; 95% CI 2.5 - 4.1). Conclusions. The adapted ETAT process may serve as a reliable triage tool for busy paediatric medical emergency units in resource-constrained countries and could be evaluated further in community emergency settings

    An adapted triage tool (ETAT) at Red Cross War Memorial Children’s Hospital Medical Emergency Unit, Cape Town: An evaluation

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    Objective. To evaluate the efficacy of an adapted Emergency Triage Assessment and Treatment (ETAT) tool at a children’s hospital. Design. A two-armed descriptive study. Setting. Red Cross War Memorial Children’s Hospital, Cape Town, South Africa. Methods. Triage data on 1 309 children from October 2007 and July 2009 were analysed. The number of children in each triage category (red (emergency), orange (urgent or priority) and green (non-urgent)) and their disposal were evaluated. Results. 1. The October 2007 series: 902 children aged 5 days - 15 years were evaluated. Their median age was 20 (interquartile range (IQR) 7 - 50) months, and 58.8% (n=530) were triaged green, 37.5% (n=338) orange and 3.8% (n=34) red. Over 90% of children in the green category were discharged (478/530), while 32.5% of children triaged orange (110/338) and 52.9% of children triaged red (18/34) were admitted. There was a significant increase in admission rate for each triage colour change from green through orange to red after adjustment for age category (risk ratio (RR) 2.6; 95% confidence interval (CI) 2.2 - 3.1). 2. The July 2009 cohort: 407 children with a median age of 22 months (IQR 7 - 53 months) were enrolled. Twelve children (2.9%) were triaged red, 187 (45.9%) orange and 208 (51.1%) green. A quarter (101/407) of the children triaged were admitted: 91.7% (11/12) from the red category and 36.9% (69/187) from the orange category were admitted, while 89.9% of children in the green category (187/208) were discharged. After adjusting for age category, admissions increased by more than 300% for every change in triage acuity (RR 3.2; 95% CI 2.5 - 4.1). Conclusions. The adapted ETAT process may serve as a reliable triage tool for busy paediatric medical emergency units in resource-constrained countries and could be evaluated further in community emergency settings

    The angiogenic factor platelet-derived endothelial cell growth factor/thymidine phosphorylase is up-regulated in breast cancer epithelium and endothelium.

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    Tumour angiogenesis is a complex multistep process regulated by a number of angiogenic factors. One such factor, platelet-derived endothelial cell growth factor has recently been shown to be thymidine phosphorylase (TP). TP catalyses the reversible phosphorylation of thymidine to deoxyribose-1-phosphate and thymine. Although known to be generally elevated in tumours, the expression of this enzyme in breast carcinomas is unknown. Therefore, we used ribonuclease protection assays and immunohistochemistry to examine the expression of TP in 240 primary breast carcinomas. Nuclear and/or cytoplasmic TP expression was observed in the neoplastic tumour epithelium in 53% of tumours. Immunoreactivity was also often present in the stromal, inflammatory and endothelial cell elements. Although endothelial cell staining was usually focal, immunoreactivity was observed in 61% of tumours and was prominent at the tumour periphery, an area where tumour angiogenesis is most active. Tumour cell TP expression was significantly inversely correlated with grade (P = 0.05) and size (P = 0.003) but no association was observed with other tumour variables. These findings suggest that TP is important for remodelling the existing vasculature early in tumour development, consistent with its chemotactic non-mitogenic properties, and that additional angiogenic factors are more important for other angiogenic processes like endothelial cell proliferation. Relapse-free survival was higher in node-positive patients with elevated TP (P = 0.05) but not in other patient groups. This might be due to the potentiation of chemotherapeutic agents like methotrexate by TP. Therefore, this enzyme might be a prediction marker for response to chemotherapy

    A Randomized, Placebo-Controlled, Double-Blind Trial of the Effect of Combined Therapy With Deferoxamine and Deferiprone on Myocardial Iron in Thalassemia Major Using Cardiovascular Magnetic Resonance

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    Background— Cardiac complications secondary to iron overload are the leading cause of death in β-thalassemia major. Approximately two thirds of patients maintained on the parenteral iron chelator deferoxamine have myocardial iron loading. The oral iron chelator deferiprone has been demonstrated to remove myocardial iron, and it has been proposed that in combination with deferoxamine it may have additional effect. Methods and Results— Myocardial iron loading was assessed with the use of myocardial T2* cardiovascular magnetic resonance in 167 patients with thalassemia major receiving standard maintenance chelation monotherapy with subcutaneous deferoxamine. Of these patients, 65 with mild to moderate myocardial iron loading (T2* 8 to 20 ms) entered the trial with continuation of subcutaneous deferoxamine and were randomized to receive additional oral placebo (deferoxamine group) or oral deferiprone 75 mg/kg per day (combined group). The primary end point was the change in myocardial T2* over 12 months. Secondary end points of endothelial function (flow-mediated dilatation of the brachial artery) and cardiac function were also measured with cardiovascular magnetic resonance. There were significant improvements in the combined treatment group compared with the deferoxamine group in myocardial T2* (ratio of change in geometric means 1.50 versus 1.24; P =0.02), absolute left ventricular ejection fraction (2.6% versus 0.6%; P =0.05), and absolute endothelial function (8.8% versus 3.3%; P =0.02). There was also a significantly greater improvement in serum ferritin in the combined group (−976 versus −233 μg/L; P <0.001). Conclusions— In comparison to the standard chelation monotherapy of deferoxamine, combination treatment with additional deferiprone reduced myocardial iron and improved the ejection fraction and endothelial function in thalassemia major patients with mild to moderate cardiac iron loading

    Total synthesis and biological evaluation of the tetramic acid based natural product harzianic acid and its stereoisomers

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    Financial support for this project was provided by Cancer Research UK (Grant No. C21383/A6950)The bioactive natural product harzianic acid was prepared for the first time in just six steps (longest linear sequence) with an overall yield of 22%. The identification of conditions to telescope amide bond formation and a Lacey-Dieckmann reaction into one pot proved important. The three stereoisomers of harzianic acid were also prepared, providing material for comparison of their biological activity. While all of the isomers promoted root growth, improved antifungal activity was unexpectedly associated with isomers in the enantiomeric series opposite that of harzianic acid.Publisher PDFPeer reviewe
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