395 research outputs found

    Do hormonal contraceptives stimulate growth of neurofibromas? A survey on 59 NF1 patients

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    BACKGROUND: Neurofibromas are benign tumors of the peripheral nerves and hallmark of neurofibromatosis type 1 (NF1), a tumor suppressor gene syndrome. Neurofibromas mostly start developing at puberty and can increase in size and number during pregnancy. Expression of progesterone receptors has been found in 75% of the tumors. Many female NF1 patients are thus concerned about the possibility that hormonal contraceptives may stimulate the growth of their neurofibromas. METHODS: A survey was carried out on 59 female NF1 patients who are practicing or have practiced hormonal contraception to examine the effect of the various contraceptives on the growth of neurofibromas. RESULTS: Majority (53 out of 58) of patients who received oral estrogen-progestogen or pure progestogen preparations reported no associated tumor growth. In contrast, significant tumor growth was reported by two patients who received depot contraceptive containing high dose of synthetic progesterone. CONCLUSIONS: Oral contraceptives do not seem to stimulate the growth of neurofibromas in NF1 patients. High doses of progesterone might stimulate the growth of neurofibromas and deserve more caution

    Extensive Copy-Number Variation of Young Genes across Stickleback Populations

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    MM received funding from the Max Planck innovation funds for this project. PGDF was supported by a Marie Curie European Reintegration Grant (proposal nr 270891). CE was supported by German Science Foundation grants (DFG, EI 841/4-1 and EI 841/6-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    A Platform-Independent Method for Detecting Errors in Metagenomic Sequencing Data: DRISEE

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    We provide a novel method, DRISEE (duplicate read inferred sequencing error estimation), to assess sequencing quality (alternatively referred to as “noise” or “error”) within and/or between sequencing samples. DRISEE provides positional error estimates that can be used to inform read trimming within a sample. It also provides global (whole sample) error estimates that can be used to identify samples with high or varying levels of sequencing error that may confound downstream analyses, particularly in the case of studies that utilize data from multiple sequencing samples. For shotgun metagenomic data, we believe that DRISEE provides estimates of sequencing error that are more accurate and less constrained by technical limitations than existing methods that rely on reference genomes or the use of scores (e.g. Phred). Here, DRISEE is applied to (non amplicon) data sets from both the 454 and Illumina platforms. The DRISEE error estimate is obtained by analyzing sets of artifactual duplicate reads (ADRs), a known by-product of both sequencing platforms. We present DRISEE as an open-source, platform-independent method to assess sequencing error in shotgun metagenomic data, and utilize it to discover previously uncharacterized error in de novo sequence data from the 454 and Illumina sequencing platforms

    A Comparison of rpoB and 16S rRNA as Markers in Pyrosequencing Studies of Bacterial Diversity

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    Background: The 16S rRNA gene is the gold standard in molecular surveys of bacterial and archaeal diversity, but it has the disadvantages that it is often multiple-copy, has little resolution below the species level and cannot be readily interpreted in an evolutionary framework. We compared the 16S rRNA marker with the single-copy, protein-coding rpoB marker by amplifying and sequencing both from a single soil sample. Because the higher genetic resolution of the rpoB gene prohibits its use as a universal marker, we employed consensus-degenerate primers targeting the Proteobacteria. <p/>Methodology/Principal Findings: Pyrosequencing can be problematic because of the poor resolution of homopolymer runs. As these erroneous runs disrupt the reading frame of protein-coding sequences, removal of sequences containing nonsense mutations was found to be a valuable filter in addition to flowgram-based denoising. Although both markers gave similar estimates of total diversity, the rpoB marker revealed more species, requiring an order of magnitude fewer reads to obtain 90% of the true diversity. The application of population genetic methods was demonstrated on a particularly abundant sequence cluster. <p/>Conclusions/Significance: The rpoB marker can be a complement to the 16S rRNA marker for high throughput microbial diversity studies focusing on specific taxonomic groups. Additional error filtering is possible and tests for recombination or selection can be employed

    Metagenomic and Metatranscriptomic Analysis of Microbial Community Structure and Gene Expression of Activated Sludge

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    The present study applied both metagenomic and metatranscriptomic approaches to characterize microbial structure and gene expression of an activated sludge community from a municipal wastewater treatment plant in Hong Kong. DNA and cDNA were sequenced by Illumina Hi-seq2000 at a depth of 2.4 Gbp. Taxonomic analysis by MG-RAST showed bacteria were dominant in both DNA and cDNA datasets. The taxonomic profile obtained by BLAST against SILVA SSUref database and annotation by MEGAN showed that activated sludge was dominated by Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Verrucomicrobia phyla in both DNA and cDNA datasets. Global gene expression annotation based on KEGG metabolism pathway displayed slight disagreement between the DNA and cDNA datasets. Further gene expression annotation focusing on nitrogen removal revealed that denitrification-related genes sequences dominated in both DNA and cDNA datasets, while nitrifying genes were also expressed in relative high levels. Specially, ammonia monooxygenase and hydroxylamine oxidase demonstrated the high cDNA/DNA ratios in the present study, indicating strong nitrification activity. Enzyme subunits gene sequences annotation discovered that subunits of ammonia monooxygenase (amoA, amoB, amoC) and hydroxylamine oxygenase had higher expression levels compared with subunits of the other enzymes genes. Taxonomic profiles of selected enzymes (ammonia monooxygenase and hydroxylamine oxygenase) showed that ammonia-oxidizing bacteria present mainly belonged to Nitrosomonas and Nitrosospira species and no ammonia-oxidizing Archaea sequences were detected in both DNA and cDNA datasets

    Parents’ experiences of caring for a young person with neurofibromatosis type 1 (NF1): a qualitative study

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    Neurofibromatosis type 1 (NF1) is a variable and unpredictable genetic condition that can lead to changes to an individual’s appearance. Research has started to explore children’s and young people’s experiences of living with the condition; however, there is a lack of research with parents. This exploratory qualitative study set out to examine parents’ experiences of caring for a young person with NF1. Seven parents took part in semi structured interviews which were subjected to a thematic analysis. Three key themes were identified which related to managing the uncertainty of the condition, the impact of an altered appearance, and others’ awareness and understanding of NF1. Parents felt that understanding NF1 themselves in order to support their child was beneficial whilst a perceived lack of understanding by others was cited as a significant challenge. Parents require trustworthy information and also more widely call for greater understanding and awareness of the condition
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