153 research outputs found

    Type F congenital quadricuspid aortic valve: A very rare case diagnosed by 3-dimenional transoesophageal echocardiography

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    Congenital quadricuspid aortic valve (QAV) is a rare cardiac anomaly. Several different anatomical variations of a quadricuspid aortic valve have been described. Aortic regurgitation is the predominant valvular dysfunction associated with QAV and patients tend to present in their 5(th) or 6(th) decade of life. This anomaly is rarely picked up by transthoracic echocardiogram (TTE). A comprehensive transoesophageal echocardiography (TOE) study is more likely to diagnose it. We describe a very rare type of QAV - Type F in a 52-year-old lady who presented with symptoms of shortness of breath and pre-syncope. We include TOE images and intra-operative valve images

    Inhibition of telomerase activity by HDV ribozyme in cancers

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    <p>Abstract</p> <p>Background</p> <p>Telomerase plays an important role in cell proliferation and carcinogenesis and is believed to be a good target for anti-cancer drugs. Elimination of template function of telomerase RNA may repress the telomerase activity.</p> <p>Methods</p> <p>A pseudo-knotted HDV ribozyme (g.RZ57) directed against the RNA component of human telomerase (hTR) was designed and synthesized. An in vitro transcription plasmid and a eukaryotic expression plasmid of ribozyme were constructed. The eukaryotic expression plasmid was induced into heptocellular carcinoma 7402 cells, colon cancer HCT116 cells and L02 hepatocytes respectively. Then we determine the cleavage activity of ribozyme against human telomerase RNA component (hTR) both in vitro and in vivo, and detect telomerase activity continuously.</p> <p>Results</p> <p>HDV ribozyme showed a specific cleavage activity against the telomerase RNA in vitro. The maximum cleavage ratio reached about 70.4%. Transfection of HDV ribozyme into 7402 cells and colon cancer cells HCT116 led to growth arrest and the spontaneous apoptosis of cells, and the telomerase activity dropped to 10% of that before.</p> <p>Conclussion</p> <p>HDV ribozyme (g.RZ57) is an effective strategy for gene therapy.</p

    What Do Men Want from a Health Screening Mobile App? A Qualitative Study.

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    There is a lack of mobile app which aims to improve health screening uptake developed for men. As part of the study to develop an effective mobile app to increase health screening uptake in men, we conducted a needs assessment to find out what do men want from a health screening mobile app. In-depth interviews and focus group discussions were conducted with 31 men from a banking institution in Kuala Lumpur. The participants were purposely sampled according to their job position, age, ethnicity and screening status. The recruitment was stopped once data saturation was achieved. The audio-recorded interviews were transcribed verbatim and analyzed using thematic approach. Three themes emerged from the analysis and they were: content, feature and dissemination. In terms of the content, men wanted the app to provide information regarding health screening and functions that can assess their health; which must be personalized to them and are trustable. The app must have user-friendly features in terms of information delivery, ease of use, attention allocation and social connectivity. For dissemination, men proposed that advertisements, recommendations by health professionals, providing incentive and integrating the app as into existing systems may help to increase the dissemination of the app. This study identified important factors that need to be considered when developing a mobile app to improve health screening uptake. Future studies on mobile app development should elicit users' preference and need in terms of its content, features and dissemination strategies to improve the acceptability and the chance of successful implementation

    siRNA-Mediated Gene Targeting in Aedes aegypti Embryos Reveals That Frazzled Regulates Vector Mosquito CNS Development

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    Although mosquito genome projects uncovered orthologues of many known developmental regulatory genes, extremely little is known about the development of vector mosquitoes. Here, we investigate the role of the Netrin receptor frazzled (fra) during embryonic nerve cord development of two vector mosquito species. Fra expression is detected in neurons just prior to and during axonogenesis in the embryonic ventral nerve cord of Aedes aegypti (dengue vector) and Anopheles gambiae (malaria vector). Analysis of fra function was investigated through siRNA-mediated knockdown in Ae. aegypti embryos. Confirmation of fra knockdown, which was maintained throughout embryogenesis, indicated that microinjection of siRNA is an effective method for studying gene function in Ae. aegypti embryos. Loss of fra during Ae. aegypti development results in thin and missing commissural axons. These defects are qualitatively similar to those observed in Dr. melanogaster fra null mutants. However, the Aa. aegypti knockdown phenotype is stronger and bears resemblance to the Drosophila commissureless mutant phenotype. The results of this investigation, the first targeted knockdown of a gene during vector mosquito embryogenesis, suggest that although Fra plays a critical role during development of the Ae. aegypti ventral nerve cord, mechanisms regulating embryonic commissural axon guidance have evolved in distantly related insects

    Human Telomerase Reverse Transcriptase (hTERT) Q169 Is Essential for Telomerase Function In Vitro and In Vivo

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    BACKGROUND:Telomerase is a reverse transcriptase that maintains the telomeres of linear chromosomes and preserves genomic integrity. The core components are a catalytic protein subunit, the telomerase reverse transcriptase (TERT), and an RNA subunit, the telomerase RNA (TR). Telomerase is unique in its ability to catalyze processive DNA synthesis, which is facilitated by telomere-specific DNA-binding domains in TERT called anchor sites. A conserved glutamine residue in the TERT N-terminus is important for anchor site interactions in lower eukaryotes. The significance of this residue in higher eukaryotes, however, has not been investigated. METHODOLOGY/PRINCIPAL FINDINGS:To understand the significance of this residue in higher eukaryotes, we performed site-directed mutagenesis on human TERT (hTERT) Q169 to create neutral (Q169A), conservative (Q169N), and non-conservative (Q169D) mutant proteins. We show that these mutations severely compromise telomerase activity in vitro and in vivo. The functional defects are not due to abrogated interactions with hTR or telomeric ssDNA. However, substitution of hTERT Q169 dramatically impaired the ability of telomerase to incorporate nucleotides at the second position of the template. Furthermore, Q169 mutagenesis altered the relative strength of hTERT-telomeric ssDNA interactions, which identifies Q169 as a novel residue in hTERT required for optimal primer binding. Proteolysis experiments indicate that Q169 substitution alters the protease-sensitivity of the hTERT N-terminus, indicating that a conformational change in this region of hTERT is likely critical for catalytic function. CONCLUSIONS/SIGNIFICANCE:We provide the first detailed evidence regarding the biochemical and cellular roles of an evolutionarily-conserved Gln residue in higher eukaryotes. Collectively, our results indicate that Q169 is needed to maintain the hTERT N-terminus in a conformation that is necessary for optimal enzyme-primer interactions and nucleotide incorporation. We show that Q169 is critical for the structure and function of human telomerase, thereby identifying a novel residue in hTERT that may be amenable to therapeutic intervention

    Alien Invasive Slider Turtle in Unpredicted Habitat: A Matter of Niche Shift or of Predictors Studied?

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    BACKGROUND: Species Distribution Models (SDMs) aim on the characterization of a species' ecological niche and project it into geographic space. The result is a map of the species' potential distribution, which is, for instance, helpful to predict the capability of alien invasive species. With regard to alien invasive species, recently several authors observed a mismatch between potential distributions of native and invasive ranges derived from SDMs and, as an explanation, ecological niche shift during biological invasion has been suggested. We studied the physiologically well known Slider turtle from North America which today is widely distributed over the globe and address the issue of ecological niche shift versus choice of ecological predictors used for model building, i.e., by deriving SDMs using multiple sets of climatic predictor. PRINCIPAL FINDINGS: In one SDM, predictors were used aiming to mirror the physiological limits of the Slider turtle. It was compared to numerous other models based on various sets of ecological predictors or predictors aiming at comprehensiveness. The SDM focusing on the study species' physiological limits depicts the target species' worldwide potential distribution better than any of the other approaches. CONCLUSION: These results suggest that a natural history-driven understanding is crucial in developing statistical models of ecological niches (as SDMs) while "comprehensive" or "standard" sets of ecological predictors may be of limited use

    Yeast IME2 Functions Early in Meiosis Upstream of Cell Cycle-Regulated SBF and MBF Targets

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    BACKGROUND: In Saccharomyces cerevisiae, the G1 cyclin/cyclin-dependent kinase (CDK) complexes Cln1,-2,-3/Cdk1 promote S phase entry during the mitotic cell cycle but do not function during meiosis. It has been proposed that the meiosis-specific protein kinase Ime2, which is required for normal timing of pre-meiotic DNA replication, is equivalent to Cln1,-2/Cdk1. These two CDK complexes directly catalyze phosphorylation of the B-type cyclin/CDK inhibitor Sic1 during the cell cycle to enable its destruction. As a result, Clb5,-6/Cdk1 become activated and facilitate initiation of DNA replication. While Ime2 is required for Sic1 destruction during meiosis, evidence now suggests that Ime2 does not directly catalyze Sic1 phosphorylation to target it for destabilization as Cln1,-2/Cdk1 do during the cell cycle. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that Sic1 is eventually degraded in meiotic cells lacking the IME2 gene (ime2Δ), supporting an indirect role of Ime2 in Sic1 destruction. We further examined global RNA expression comparing wild type and ime2Δ cells. Analysis of these expression data has provided evidence that Ime2 is required early in meiosis for normal transcription of many genes that are also periodically expressed during late G1 of the cell cycle. CONCLUSIONS/SIGNIFICANCE: Our results place Ime2 at a position in the early meiotic pathway that lies upstream of the position occupied by Cln1,-2/Cdk1 in the analogous cell cycle pathway. Thus, Ime2 may functionally resemble Cln3/Cdk1 in promoting S phase entry, or it could play a role even further upstream in the corresponding meiotic cascade

    The Plant Pathogen Pseudomonas syringae pv. tomato Is Genetically Monomorphic and under Strong Selection to Evade Tomato Immunity

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    Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP) in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain

    European Red List of Habitats Part 1. Marine habitats

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    The European Red List of Habitats provides an overview of the risk of collapse (degree of endangerment) of marine, terrestrial and freshwater habitats in the European Union (EU28) and adjacent regions (EU28+), based on a consistent set of categories and criteria, and detailed data and expert knowledge from involved countries1. A total of 257 benthic marine habitat types were assessed. In total, 19% (EU28) and 18% (EU28+) of the evaluated habitats were assessed as threatened in categories Critically Endangered, Endangered and Vulnerable. An additional 12% were Near Threatened in the EU28 and 11% in the EU28+. These figures are approximately doubled if Data Deficient habitats are excluded. The percentage of threatened habitat types differs across the regional seas. The highest proportion of threatened habitats in the EU28 was found in the Mediterranean Sea (32%), followed by the North-East Atlantic (23%), the Black Sea (13%) and then the Baltic Sea (8%). There was a similar pattern in the EU28+. The most frequently cited pressures and threats were similar across the four regional seas: pollution (eutrophication), biological resource use other than agriculture or forestry (mainly fishing but also aquaculture), natural system modifications (e.g. dredging and sea defence works), urbanisation and climate change. Even for habitats where the assessment outcome was Data Deficient, the Red List assessment process has resulted in the compilation of a substantial body of useful information to support the conservation of marine habitats
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