711 research outputs found

    Chromosome numbers in Begonia.

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    The somatic chromosome numbers of 100 Begonia species were counted, of which 72 have been determined for the first time. Eighteen different numbers have been established, ranging between 22 and 156, fifteen of which could be fitted into a tentative scheme of five polyploid series. The most common numbers were 22 (14 species), 28 (35 species) and 56 (17 species). The species have been grouped into sections according to Irmscher. In some cases these sections appeared to have a characteristic chromosome number whereas in others, e.g. Pritzelia and Begoniastrum, a great diversity in chromosome number was encountered. [For earlier work see H.A., 39: 5182.]-Univ. Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission

    Chromosome numbers in. Begonia. 2.

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    The somatic chromosome numbers are presented of 90 Begonia spp. of African, Asian and American origin, including a few of those previously listed [see H.A., 40: 1600] whose nomenclature or chromosome numbers are reconsidered. Sixteen different numbers were found, ranging between 16 and 76. The most common were 28 (26 species), 38 (10 species) and 56 (15 species). [For related work see H.A., 41: 7120.]. (Abstract retrieved from CAB Abstracts by CABI’s permission

    Chromosome numbers in Begonia.3.

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    The somatic chromosome numbers are presented of 34 spp. of African, Asiatic and American origin. Many spp. had not previously been investigated cytologically. [For part 2 see HcA 42, 1737.]. (Abstract retrieved from CAB Abstracts by CABI’s permission

    U.S. Standing in the World: Causes, Consequences, and the Future

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    America’s global standing has become a central concern of U.S. leaders and citizens. U.S. leaders, regardless of party, pledge to “restore U.S. standing” as a central goal of America’s foreign policy agenda. Standing has been the subject of widespread public discussion and intellectual debate. Yet despite all this attention, three issues fundamental to standing have been relatively ignored: -What is standing and how has it varied?-What causes standing to rise and fall?-What impact does standing have on U.S. foreign policy?This task force answers these questions by synthesizing what we now know about U.S. standing and/or identifying what we need to know to understand better a topic of clear national and international importance

    DNA damage and tissue repair: What we can learn from planaria.

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    Faithful renewal of aging and damaged tissues is central to organismal lifespan. Stem cells (SCs) generate the cellular progeny that replenish adult tissues across the body but this task becomes increasingly compromised over time. The age related decline in SC-mediated tissue maintenance is a multifactorial event that commonly affects genome integrity. The presence of DNA damage in SCs that are under continuous demand to divide poses a great risk for age-related disorders such as cancer. However, performing analysis of SCs with genomic instability and the DNA damage response during tissue renewal present significant challenges. Here we introduce an alternative experimental system based on the planaria flatworm Schmidtea mediterranea to address at the organismal level studies intersecting SC-mediated tissue renewal in the presence of genomic instability. Planaria have abundant SCs (neoblasts) that maintain high rates of cellular turnover and a variety of molecular tools have been developed to induce DNA damage and dissect how neoblasts respond to this stressor. S. mediterranea displays high evolutionary conservation of DNA repair mechanisms and signaling pathways regulating adult SCs. We describe genetically induced-DNA damage models and highlight body-wide signals affecting cellular decisions such as survival, proliferation, and death in the presence of genomic instability. We also discuss transcriptomic changes in the DNA damage response during injury repair and propose DNA repair as key component of tissue regeneration. Additional studies using planaria will provide insights about mechanisms regulating survival and growth of cells with DNA damage during tissue renewal and regeneration

    Retinol-Binding Protein 4 and Insulin Resistance in Polycystic Ovary Syndrome

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    OBJECTIVE—Polycystic ovary syndrome (PCOS) is an insulin-resistant state with insulin resistance being an established therapeutic target; however, measurement of insulin resistance remains challenging. We aimed to 1) determine serum retinol-binding protein 4 (RBP4) levels (purported to reflect insulin resistance) in women with PCOS and control subjects, 2) examine the relationship of RBP4 to conventional markers of insulin resistance, and 3) examine RBP4 changes with interventions modulating insulin resistance in overweight women with PCOS

    Harnessing Expression Data to Identify Novel Candidate Genes in Polycystic Ovary Syndrome

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    Novel pathways in polycystic ovary syndrome (PCOS) are being identified in gene expression studies in PCOS tissues; such pathways may contain key genes in disease etiology. Previous expression studies identified both dickkopf homolog 1 (DKK1) and DnaJ (Hsp40) homolog, subfamily B, member 1 (DNAJB1) as differentially expressed in PCOS tissue, implicating them as candidates for PCOS susceptibility. To test this, we genotyped a discovery cohort of 335 PCOS cases and 198 healthy controls for three DKK1 single nucleotide polymorphisms (SNPs) and four DNAJB1 SNPs and a replication cohort of 396 PCOS cases and 306 healthy controls for 1 DKK1 SNP and 1 DNAJB1 SNP. SNPs and haplotypes were determined and tested for association with PCOS and component phenotypes. We found that no single nucleotide polymorphisms were associated with PCOS risk; however, the major allele of rs1569198 from DKK1 was associated with increased total testosterone (discovery cohort P = 0.0035) and dehydroepiandrosterone sulfate (replication cohort P = 0.05). Minor allele carriers at rs3962158 from DNAJB1 had increased fasting insulin (discovery cohort P = 0.003), increased HOMA-IR (discovery cohort P = 0.006; replication cohort P = 0.036), and increased HOMA-%B (discovery cohort P = 0.004). Carriers of haplotype 2 at DNAJB1 also had increased fasting insulin, HOMA-IR, and HOMA-%B. These findings suggest that genetic variation in DKK1 and DNAJB1 may have a role in the hyperandrogenic and metabolic dysfunction of PCOS, respectively. Our results also demonstrate the utility of gene expression data as a source of novel candidate genes in PCOS, a complex and still incompletely defined disease, for which alternative methods of gene identification are needed

    Treatment strategies for women with WHO group II anovulation : systematic review and network meta-analysis

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    Funding: The work was supported by an Australian government research training programme scholarship (held by RW) and the Australian National Health and Medical Research Council funded Centre for Research Excellence in Polycystic Ovary Syndrome (APP1078444).Peer reviewedPublisher PD

    Using formative evaluation in an implementation project to increase vaccination rates in high-risk veterans: QUERI Series

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    <p>Abstract</p> <p>Background</p> <p>Implementation of research into practice in health care systems is a challenging and often unsuccessful endeavor. The United States Department of Veterans Affairs (VA) Quality Enhancement Research Initiative (QUERI) research teams include formative evaluations (FE) in their action-oriented VA implementation projects to identify critical information about the processes of implementation that can guide adjustments to project activities, in order to better meet project goals. This article describes the development and use of FE in an action-oriented implementation research project.</p> <p>Methods</p> <p>This two-year action-oriented implementation research project was conducted at 23 VA Spinal Cord Injury (SCI) Centers, and targeted patients, staff and the system of care, such as administration and information technology. Data for FE were collected by electronic and paper surveys, semi-structured and open-ended interviews, notes during conference calls, and exchange of e-mail messages. Specific questions were developed for each intervention (designed to improve vaccination rates for influenza in veterans with spinal cord injury and disorder); informants were selected for their knowledge of interventions and their use in SCI Centers.</p> <p>Results</p> <p>Data from FE were compiled separately for each intervention to describe barriers to progress and guide adjustments to implementation activities. These data addressed the processes of implementing the interventions, problem-solving activities and the status of interventions at SCI Centers.</p> <p>Conclusion</p> <p>Formative evaluations provided the project team with a broad view of the processes of implementing multi-targeted interventions as well as the evolving status of the related best practice. Using FE was useful, although the challenges of conducting FE for non-field researchers should be addressed. Work is needed to develop methods for conducting FE across multiple sites, as well as acknowledging variations in local contexts that affect implementation of interventions.</p

    A comparative framework: how broadly applicable is a 'rigorous' critical junctures framework?

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    The paper tests Hogan and Doyle's (2007, 2008) framework for examining critical junctures. This framework sought to incorporate the concept of ideational change in understanding critical junctures. Until its development, frameworks utilized in identifying critical junctures were subjective, seeking only to identify crisis, and subsequent policy changes, arguing that one invariably led to the other, as both occurred around the same time. Hogan and Doyle (2007, 2008) hypothesized ideational change as an intermediating variable in their framework, determining if, and when, a crisis leads to radical policy change. Here we test this framework on cases similar to, but different from, those employed in developing the exemplar. This will enable us determine whether the framework's relegation of ideational change to a condition of crisis holds, or, if ideational change has more importance than is ascribed to it by this framework. This will also enable us determined if the framework itself is robust, and fit for the purposes it was designed to perform — identifying the nature of policy change
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