331 research outputs found

    Genome-wide analyses of light-regulated genes in Aspergillus nidulans reveal a complex interplay between different photoreceptors and novel photoreceptor functions

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    Fungi sense light of different wavelengths using blue-, green-, and red-light photoreceptors. Blue light sensing requires the “white-collar” proteins with flavin as chromophore, and red light is sensed through phytochrome. Here we analyzed genome-wide gene expression changes caused by short-term, low-light intensity illumination with blue-, red- or far-red light in Aspergillus nidulans and found that more than 1100 genes were differentially regulated. The largest number of up- and downregulated genes depended on the phytochrome FphA and the attached HOG pathway. FphA and the white-collar orthologue LreA fulfill activating but also repressing functions under all light conditions and both appear to have roles in the dark. Additionally, we found about 100 genes, which are red-light induced in the absence of phytochrome, suggesting alternative red-light sensing systems. We also found blue-light induced genes in the absence of the blue-light receptor LreA. We present evidence that cryptochrome may be part of this regulatory cue, but that phytochrome is essential for the response. In addition to in vivo data showing that FphA is involved in blue-light sensing, we performed spectroscopy of purified phytochrome and show that it responds indeed to blue light

    Centerscope

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    Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.

    A reference frame for blood volume in children and adolescents

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    BACKGROUND: Our primary purpose was to determine the normal range and variability of blood volume (BV) in healthy children, in order to provide reference values during childhood and adolescence. Our secondary aim was to correlate these vascular volumes to body size parameters and pubertal stages, in order to determine the best normalisation parameter. METHODS: Plasma volume (PV) and red cell volume (RCV) were measured and F-cell ratio was calculated in 77 children with idiopathic nephrotic syndrome in drug-free remission (mean age, 9.8 ± 4.6 y). BV was calculated as the sum of PV and RCV. Due to the dependence of these values on age, size and sex, all data were normalised for body size parameters. RESULTS: BV normalised for lean body mass (LBM) did not differ significantly by sex (p < 0.376) or pubertal stage (p < 0.180), in contrast to normalisation for the other anthropometric parameters. There was no significant difference between reference values for children and adults. CONCLUSION: LBM was the anthropometric index most closely correlated to vascular fluid volumes, independent of age, gender and pubertal stage

    Saudi views on consenting for research on medical records and leftover tissue samples

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    <p>Abstract</p> <p>Background</p> <p>Consenting for retrospective medical records-based research (MR) and leftover tissue-based research (TR) continues to be controversial. Our objective was to survey Saudis attending outpatient clinics at a tertiary care hospital on their personal preference and perceptions of norm and current practice in relation to consenting for MR and TR.</p> <p>Methods</p> <p>We surveyed 528 Saudis attending clinics at a tertiary care hospital in Saudi Arabia to explore their preferences and perceptions of norm and current practice. The respondents selected one of 7 options from each of 6 questionnaires.</p> <p>Results</p> <p>Respondents' mean (SD) age was 33 (11) years, 42% were males, 56% were patients, 84% had ≥ secondary school education, and 10% had previously volunteered for research. Respectively, 40% and 49% perceived that the norm is to conduct MR and TR without consent and 38% and 37% with general or proposal-specific consent; the rest objected to such research. There was significant difference in the distribution of choices according to health status (patients vs. companions) for MR (adjusted Kruskal-Wallis test P = 0.03) but not to age group, gender, education level, or previous participation in research (unadjusted P = 0.02 - 0.59). The distributions of perceptions of current practice and norm were similar (unadjusted Marginal Homogeneity test P = 0.44 for MR and P = 0.89 for TR), whereas the distributions of preferences and perceptions of norm were different (adjusted P = 0.09 for MR and P = 0.02 for TR). The distributions of perceptions of norm, preferences, and perceptions of current practice for MR were significantly different from those of TR (adjusted P < 0.009 for all).</p> <p>Conclusions</p> <p>We conclude that: 1) there is a considerable diversity among Saudi views regarding consenting for retrospective research which may be related to health status, 2) the distribution of perceptions of norm was similar to the distribution of perceptions of current practice but different from that of preferences, and 3) MR and TR are perceived differently in regard to consenting.</p

    Learners' decisions for attending Pediatric Grand Rounds: a qualitative and quantitative study

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    BACKGROUND: Although grand rounds plays a major educational role at academic medical centers, there has been little investigation into the factors influencing the learners' decision to attend. Greater awareness of attendees' expectations may allow grand rounds planners to better accommodate the learners' perspective, potentially making continuing education activities more attractive and inviting. METHODS: We used both qualitative (part A) and quantitative (part B) techniques to investigate the motivators and barriers to grand rounds attendance. Part A investigated contextual factors influencing attendance as expressed through attendee interviews. Transcripts of the interviews were analyzed using grounded theory techniques. We created a concept map linking key factors and their relationships. In part B we quantified the motivators and barriers identified during the initial interviews through a survey of the grand rounds audience. RESULTS: Sixteen persons voluntarily took part in the qualitative study (part A) by participating in one of seven group interview sessions. Of the 14 themes that emerged from these sessions, the most frequent factors motivating attendance involved competent practice and the need to know. All sessions discussed intellectual stimulation, social interaction, time constraints and convenience, licensure, content and format, and absence of cost for attending sessions. The 59 respondents to the survey (part B) identified clinically-useful topics (85%), continuing education credit (46%), cutting-edge research (27%), networking (22%), and refreshments (8%) as motivators and non-relevant topics (44%) and too busy to attend (56%) as barriers. CONCLUSION: Greater understanding of the consumers' perspective can allow planners to tailor the style, content, and logistics to make grand rounds more attractive and inviting
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