Protein Tyrosine Phosphatases, TC-PTP, SHP1, and SHP2, Cooperate in Rapid Dephosphorylation of Stat3 in Keratinocytes Following UVB Irradiation

Stat3 is initially dephosphorylated in murine keratinocytes in response to UVB irradiation. Treatment with Na3VO4 desensitized keratinocytes to UVB-induced apoptosis with the recovery of phosphorylated Stat3 protein levels, implying that a protein tyrosine phosphatase (PTP) is involved in this mechanism. In the current work, we report that three PTPs including TC45 (the nuclear form of TC-PTP), SHP1, and SHP2 are involved in this rapid dephosphorylation of Stat3 in keratinocytes induced by UVB irradiation. Dephosphorylation of Stat3 was increased rapidly after UVB irradiation of cultured keratinocytes. Knockdown of TC-PTP, SHP1, or SHP2 using RNAi showed that these PTPs are likely responsible for most of the rapid Stat3 dephosphorylation observed following UVB irradiation. The level of phosphorylated Stat3 was significantly higher in keratinocytes transfected with TC-PTP, SHP1, or SHP2 siRNA in the presence or absence of UVB compared with keratinocytes transfected with control siRNA. TC45 was mainly localized in the cytoplasm of keratinocytes and translocated from cytoplasm to nucleus upon UVB irradiation. Stat3 dephosphorylation was associated with nuclear translocation of TC45. Further studies revealed that knockdown of all three phosphatases, using RNAi, prevented the rapid dephosphorylation of Stat3 following UVB irradiation. In mouse epidermis, the level of phosphorylated Stat3 was initially decreased, followed by a significant increase at later time points after UVB exposure. The levels of Stat3 target genes, such as cyclin D1 and c-Myc, followed the changes in activated Stat3 in response to UVB irradiation. Collectively, these results suggest that three phosphatases, TC45, SHP1, and SHP2, are primarily responsible for UVB-mediated Stat3 dephosphorylation and may serve as part of an initial protective mechanism against UV skin carcinogenesis

Extended-Synaptotagmin-2 Mediates FGF Receptor Endocytosis and ERK Activation In Vivo

SummaryTargeting of activated plasma membrane receptors to endocytic pathways is important in determining the outcome of growth factor signaling. However, the molecular mechanisms are still poorly understood. Here, we show that the synaptotagmin-related membrane protein E-Syt2 is essential for rapid endocytosis of the activated FGF receptor and for functional signal transduction during Xenopus development. E-Syt2 depletion prevents an early phase of activated FGF receptor endocytosis that we show is required for ERK activation and the induction of the mesoderm. E-Syt2 interacts selectively with the activated FGF receptor and with Adaptin-2, and is required upstream of Ras activation and of receptor autophosphorylation for ERK activation and the induction of the mesodermal marker Xbra. The data identify E-Syt2 as an endocytic adaptor for the clathrin-mediated pathway whose function is conserved in human and suggest a broader role for the E-Syt subfamily in growth factor signaling

Early risk factors for hyperactivity-impulsivity and inattention trajectories from age 17 months to 8 years.

CONTEXT: Attention-deficit/hyperactivity disorder is an etiologically heterogeneous neurodevelopmental condition with long-term negative outcomes. However, the early developmental course of hyperactivity-impulsivity and inattention symptoms and their association with previous environmental risk factors are still poorly understood OBJECTIVES: To describe the developmental trajectories of hyperactivity-impulsivity and inattention symptoms and to identify their prenatal, perinatal, and postnatal risk factors. DESIGN: Birth cohort from the general population. SETTING: Quebec Longitudinal Study of Child Development. PARTICIPANTS: The sample consisted of 2057 individuals, followed up from age 5 months to 8 years. MAIN OUTCOME MEASURES: Prenatal, perinatal, and postnatal risk factors assessed at age 5 months were considered predictors of group membership in high hyperactivity-impulsivity and inattention trajectories from age 17 months to 8 years. RESULTS: The frequency of hyperactivity-impulsivity symptoms tended to slightly decrease with age, whereas the frequency of inattention symptoms substantially increased up to age 6 years. However, trajectories of hyperactivity-impulsivity and inattention symptoms were significantly associated with each other. Risk factors for high trajectories of both types of symptoms were premature birth (adjusted odds ratio [aOR], 1.93; 95% CI, 1.07-3.50), low birth weight (2.11; 1.12-3.98), prenatal tobacco exposure (1.41; 1.03-1.93), nonintact family (1.85; 1.26-2.70), young maternal age at birth of the target child (1.78; 1.17-2.69), paternal history of antisocial behavior (1.78; 1.28-2.47), and maternal depression (1.35; 1.18-1.54). CONCLUSIONS: A large range of early risk factors, including prenatal, perinatal social, and parental psychopathology variables, act independently to heighten the likelihood of having persistently high levels of hyperactivity-impulsivity and inattention symptoms from infancy to middle childhood. Early interventions should be experimented with to provide effective tools for attention-deficit/hyperactivity disorder prevention

Solvable Lie algebras with triangular nilradicals

All finite-dimensional indecomposable solvable Lie algebras $L(n,f)$, having the triangular algebra T(n) as their nilradical, are constructed. The number of nonnilpotent elements $f$ in $L(n,f)$ satisfies $1\leq f\leq n-1$ and the dimension of the Lie algebra is $\dim L(n,f)=f+{1/2}n(n-1)$

Antitumor Activity and Mechanism of Action of the Cyclopenta[b]benzofuran, Silvestrol

BACKGROUND. Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. METHODOLOGY/PRINCIPAL FINDINGS. Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. CONCLUSIONS/SIGNIFICANCE. Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals.Canadian Institutes of Health Research (16512, Cancer Consortium Training Grant Award, CancerConsortium Training Grant Award); US Lymphoma Foundation Award; National Institute of Health (RO1 GM073855); National Crime Information Center (017099); Cole Foundation Awar

Aggression in Low Functioning Children and Adolescents with Autistic Disorder

BACKGROUND: Parents, caregivers and mental health professionals have often reported violence and aggression in children or adolescents with autistic disorder. However, most of these observations derived from anecdotal reports, and studies on frequency and characterization of aggression in autism remain limited. Our objective was to better characterize and understand the different types of aggressive behaviors displayed by a large group of individuals with autism in different observational situations. METHODOLOGY/FINDINGS: The study was conducted on 74 children and adolescents with autism and 115 typically developing control individuals matched for sex, age and pubertal stage. Other-Injurious Behaviors (OIB) were assessed in three observational situations (parents at home, two caregivers at day-care, a nurse and a child psychiatrist during blood drawing) using validated scales. The frequency of OIB was significantly higher in individuals with autism compared to typically developing control individuals during the blood drawing (23% vs. 0%, P<0 .01). The parents observed significantly less OIB in their children than caregivers (34% vs. 58%, P<0.05). In addition, the most frequent concurrent behaviors occurring just before the appearance of OIB in individuals with autism were anxiety-related behaviors and excitation according to the parental as well as the caregiver observation. CONCLUSIONS/SIGNIFICANCE: The results suggest that in a stressful situation, such as the blood drawing, individuals with autism release their stress through behaviors such as OIB, whereas typically developing individuals regulate and express their stress through cognitive skills such as mental coping strategies, symbolization skills with representation and anticipation of the stressful situation, social interaction and verbal or non-verbal communication. The findings underline also the key role of the environment in assessing OIB and developing therapeutic perspectives, with an individual who modulates his/her behavior according to the environment, and an environment that perceives this behavior and reacts to it with different tolerance thresholds according to the observers

Training family physicians and residents in family medicine in shared decision making to improve clinical decisions regarding the use of antibiotics for acute respiratory infections: protocol for a clustered randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>To explore ways to reduce the overuse of antibiotics for acute respiratory infections (ARIs), we conducted a pilot clustered randomized controlled trial (RCT) to evaluate DECISION+, a training program in shared decision making (SDM) for family physicians (FPs). This pilot project demonstrated the feasibility of conducting a large clustered RCT and showed that DECISION+ reduced the proportion of patients who decided to use antibiotics immediately after consulting their physician. Consequently, the objective of this study is to evaluate, in patients consulting for ARIs, if exposure of physicians to a modified version of DECISION+, DECISION+2, would reduce the proportion of patients who decide to use antibiotics immediately after consulting their physician.</p> <p>Methods/design</p> <p>The study is a multi-center, two-arm, parallel clustered RCT. The 12 family practice teaching units (FPTUs) in the network of the Department of Family Medicine and Emergency Medicine of Université Laval will be randomized to a DECISION+2 intervention group (experimental group) or to a no-intervention control group. These FPTUs will recruit patients consulting family physicians and residents in family medicine enrolled in the study. There will be two data collection periods: pre-intervention (baseline) including 175 patients with ARIs in each study arm, and post-intervention including 175 patients with ARIs in each study arm (total n = 700). The primary outcome will be the proportion of patients reporting a decision to use antibiotics immediately after consulting their physician. Secondary outcome measures include: 1) physicians and patients' decisional conflict; 2) the agreement between the parties' decisional conflict scores; and 3) perception of patients and physicians that SDM occurred. Also in patients, at 2 weeks follow-up, adherence to the decision, consultation for the same reason, decisional regret, and quality of life will be assessed. Finally, in both patients and physicians, intention to engage in SDM in future clinical encounters will be assessed. Intention-to-treat analyses will be applied and account for the nested design of the trial will be taken into consideration.</p> <p>Discussion</p> <p>DECISION+2 has the potential to reduce antibiotics use for ARIs by priming physicians and patients to share decisional process and empowering patients to make informed, value-based decisions.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="NCT01116076">NCT01116076</a></p

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36