Stem cell function during plant vascular development

The plant vascular system, composed of xylem and phloem, evolved to connect plant organs and transport various molecules between them. During the post‐embryonic growth, these conductive tissues constitutively form from cells that are derived from a lateral meristem, commonly called procambium and cambium. Procambium/cambium contains pluripotent stem cells and provides a microenvironment that maintains the stem cell population. Because vascular plants continue to form new tissues and organs throughout their life cycle, the formation and maintenance of stem cells are crucial for plant growth and development. In this decade, there has been considerable progress in understanding the molecular control of the organization and maintenance of stem cells in vascular plants. Noticeable advance has been made in elucidating the role of transcription factors and major plant hormones in stem cell maintenance and vascular tissue differentiation. These studies suggest the shared regulatory mechanisms among various types of plant stem cell pools. In this review, we focus on two aspects of stem cell function in the vascular cambium, cell proliferation and cell differentiation

What traits are carried on mobile genetic elements, and why?

Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes

Treatment of psychotic symptoms in bipolar disorder with aripiprazole monotherapy: A meta-analysis

Background: We present a systematic review and meta-analysis of the available clinical trials concerning the usefulness of aripiprazole in the treatment of the psychotic symptoms in bipolar disorder.Methods: A systematic MEDLINE and repository search concerning clinical trials for aripiprazole in bipolar disorder was conducted.Results: The meta-analysis of four randomised controlled trials (RCTs) on acute mania suggests that the effect size of aripiprazole versus placebo was equal to 0.14 but a more reliable and accurate estimation is 0.18 for the total Positive and Negative Syndrome Scale (PANSS) score. The effect was higher for the PANSS-positive subscale (0.28), PANSS-hostility subscale (0.24) and PANSS-cognitive subscale (0.20), and lower for the PANSS-negative subscale (0.12). No data on the depressive phase of bipolar illness exist, while there are some data in favour of aripiprazole concerning the maintenance phase, where at week 26 all except the total PANSS score showed a significant superiority of aripiprazole over placebo (d = 0.28 for positive, d = 0.38 for the cognitive and d = 0.71 for the hostility subscales) and at week 100 the results were similar (d = 0.42, 0.63 and 0.48, respectively).Conclusion: The data analysed for the current study support the usefulness of aripiprazole against psychotic symptoms during the acute manic and maintenance phases of bipolar illness. © 2009 Fountoulakis et al; licensee BioMed Central Ltd

Exacerbations of chronic obstructive pulmonary disease: when are antibiotics indicated? A systematic review

BACKGROUND: For decades, there is an unresolved debate about adequate prescription of antibiotics for patients suffering from exacerbations of chronic obstructive pulmonary disease (COPD). The aim of this systematic review was to analyse randomised controlled trials investigating the clinical benefit of antibiotics for COPD exacerbations. METHODS: We conducted a systematic review of randomised, placebo-controlled trials assessing the effects of antibiotics on clinically relevant outcomes in patients with an exacerbation. We searched bibliographic databases, scrutinized reference lists and conference proceedings and asked the pharmaceutical industry for unpublished data. We used fixed-effects models to pool results. The primary outcome was treatment failure of COPD exacerbation treatment. RESULTS: We included 13 trials (1557 patients) of moderate to good quality. For the effects of antibiotics on treatment failure there was much heterogeneity across all trials (I(2 )= 82%). Meta-regression revealed severity of exacerbation as significant explanation for this heterogeneity (p = 0.016): Antibiotics did not reduce treatment failures in outpatients with mild to moderate exacerbations (pooled odds ratio 1.09, 95% CI 0.75–1.59, I(2 )= 18%). Inpatients with severe exacerbations had a substantial benefit on treatment failure rates (pooled odds ratio of 0.25, 95% CI 0.16–0.39, I(2 )= 0%; number-needed to treat of 4, 95% CI 3–5) and on mortality (pooled odds ratio of 0.20, 95% CI 0.06–0.62, I(2 )= 0%; number-needed to treat of 14, 95% CI 12–30). CONCLUSION: Antibiotics effectively reduce treatment failure and mortality rates in COPD patients with severe exacerbations. For patients with mild to moderate exacerbations, antibiotics may not be generally indicated and further research is needed to guide antibiotic prescription in these patients

The Durability of Public Goods Changes the Dynamics and Nature of Social Dilemmas

An implicit assumption underpins basic models of the evolution of cooperation, mutualism and altruism: The benefits (or pay-offs) of cooperation and defection are defined by the current frequency or distribution of cooperators. In social dilemmas involving durable public goods (group resources that can persist in the environment–ubiquitous from microbes to humans) this assumption is violated. Here, we examine the consequences of relaxing this assumption, allowing pay-offs to depend on both current and past numbers of cooperators. We explicitly trace the dynamic of a public good created by cooperators, and define pay-offs in terms of the current public good. By raising the importance of cooperative history in determining the current fate of cooperators, durable public goods cause novel dynamics (e.g., transient increases in cooperation in Prisoner's Dilemmas, oscillations in Snowdrift Games, or shifts in invasion thresholds in Stag-hunt Games), while changes in durability can transform one game into another, by moving invasion thresholds for cooperation or conditions for coexistence with defectors. This enlarged view challenges our understanding of social cheats. For instance, groups of cooperators can do worse than groups of defectors, if they inherit fewer public goods, while a rise in defectors no longer entails a loss of social benefits, at least not in the present moment (as highlighted by concerns over environmental lags). Wherever durable public goods have yet to reach a steady state (for instance due to external perturbations), the history of cooperation will define the ongoing dynamics of cooperators

A cross-cultural comparison of student learning patterns in higher education

Marambe, K. N., Vermunt, J. D., & Boshuizen, H. P. A. (2012). A cross-cultural comparison of student learning patterns in higher education. Higher Education, 64(3), 299-316. doi:10.1007/s10734-011-9494-zThe aim of this study was to compare student learning patterns in higher education across different cultures. A meta-analysis was performed on three large-scale studies that had used the same research instrument: the Inventory of learning Styles (ILS). The studies were conducted in the two Asian countries Sri Lanka and Indonesia and the European country The Netherlands. Students reported use of learning strategies, metacognitive strategies, conceptions of learning and learning orientations were compared in two ways: by analyses of variance of students' mean scale scores on ILS scales, as well as by comparing the factor structures of the ILS-scales between the three studies. Results showed most differences in student learning patterns between Asian and European students. However, many differences were identified between students from the two Asian countries as well. The Asian learner turned out to be a myth. Moreover, Sri Lankan students made the least use of memorising strategies of all groups. That Asian learners would have a propensity for rote learning turned out to be a myth as well. Some patterns of learning turned out to be universal and occurred in all groups, other patterns were found only among the Asian or the European students. The findings are discussed in terms of learning environment and culture as explanatory factors. Practical implications for student mobility in an international context are derived

Phosphoinositide-3 kinase inhibition modulates responses to rhinovirus by mechanisms that are predominantly independent of autophagy

Human rhinoviruses (HRV) are a major cause of exacerbations of airways disease. Aspects of cell signalling responses to HRV infection remain unclear, particularly with regard to signalling via PI3K, and the PI3K-dependent pathway, autophagy. We investigated the roles of PI3K and autophagy in the responses of epithelial cells to major and minor group HRV infection. The PI3K inhibitor 3-MA, commonly used to inhibit autophagy, markedly reduced HRV-induced cytokine induction. Further investigation of potential targets of 3-MA and comparison of results using this inhibitor to a panel of general and class I-selective PI3K inhibitors showed that several PI3Ks cooperatively regulate responses to HRV. Targeting by siRNA of the autophagy proteins Beclin-1, Atg7, LC3, alone or in combination, or targeting of the autophagy-specific class III PI3K had at most only modest effects on HRV-induced cell signalling as judged by induction of proinflammatory cytokine production. Our data indicate that PI3K and mTOR are involved in induction of proinflammatory cytokines after HRV infection, and that autophagy has little role in the cytokine response to HRV or control of HRV replication

Return to work of breast cancer survivors: a systematic review of intervention studies

<p>Abstract</p> <p>Background</p> <p>Breast cancer management has improved dramatically in the past three decades and as a result, a population of working age women is breast cancer survivor. Interventions for breast cancer survivors have shown improvements in quality of life and in physical and psychological states. In contrast, efforts aimed at stimulating re-employment and return-to-work interventions for breast cancer survivors have not kept pace. The objective of this review was to study the effects and characteristics of intervention studies on breast cancer survivors in which the outcome was return to work.</p> <p>Methods</p> <p>The Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2006), Medline, Ovid, EMBASE and PsychInfo were systematically searched for studies conducted between 1970 to February 2007. Intervention studies for female breast cancer survivors that were focused on return to work were included.</p> <p>Results</p> <p>Our search strategy identified 5219 studies. Four studies out of 100 potentially relevant abstracts were selected and included 46–317 employed women who had had mastectomy, adjuvant therapy and rehabilitation, with the outcome return to work. The intervention programs focused on improvement of physical, psychological and social recovery. Although a substantial percentage (between 75% to 85%) of patients included in these studies returned to work after rehabilitation, it is not clear whether this proportion would have been lower for patients without counseling or exercise, or any other interventions, as three out of four studies did not include a comparison group.</p> <p>Conclusion</p> <p>The most important finding of this review is the lack of methodologically sound intervention studies on breast cancer survivors with the outcome return to work. Using evidence from qualitative and observational studies on cancer and the good results of intervention studies on return to work programs and vocational rehabilitation, return to work interventions for breast cancer survivors should be further developed and evaluated.</p

Over-expression of the IGI1 leading to altered shoot-branching development related to MAX pathway in Arabidopsis

Shoot branching and growth are controlled by phytohormones such as auxin and other components in Arabidopsis. We identified a mutant (igi1) showing decreased height and bunchy branching patterns. The phenotypes reverted to the wild type in response to RNA interference with the IGI1 gene. Histochemical analysis by GUS assay revealed tissue-specific gene expression in the anther and showed that the expression levels of the IGI1 gene in apical parts, including flowers, were higher than in other parts of the plants. The auxin biosynthesis component gene, CYP79B2, was up-regulated in igi1 mutants and the IGI1 gene was down-regulated by IAA treatment. These results indicated that there is an interplay regulation between IGI1 and phytohormone auxin. Moreover, the expression of the auxin-related shoot branching regulation genes, MAX3 and MAX4, was down-regulated in igi1 mutants. Taken together, these results indicate that the overexpression of the IGI1 influenced MAX pathway in the shoot branching regulation