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Find video protocols related to scientific articles indexed in Pubmed.
Initiation codon selection is accomplished by a scanning mechanism without crucial initiation factors in Sindbis virus subgenomic mRNA.
RNA
PUBLISHED: 11-19-2014
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Translation initiation of alphavirus subgenomic mRNA (sgmRNA) can occur in the absence of several initiation factors (eIFs) in infected cells; however, the precise translation mechanism is still poorly understood. In this study, we have examined the mechanism of initiation and AUG selection in Sindbis virus (SINV) sgmRNA. Our present findings suggest that sgmRNA is translated via a scanning mechanism, since the presence of a hairpin structure before the initiation codon hampers protein synthesis directed by this mRNA. In addition, translation is partially recovered when an in-frame AUG codon is placed upstream of this hairpin. This scanning process takes place without the participation of eIF4A and active eIF2. These results, combined with our findings through modifying the SINV sgmRNA leader sequence, do not support the possibility of a direct initiation from the start codon without previous scanning, or a shunting mechanism. Moreover, studies carried out with sgmRNAs containing two alternative AUG codons within a good context for translation reveal differences in AUG selection which are dependent on the cellular context and the phosphorylation state of eIF2?. Thus, initiation at the additional AUG is strictly dependent on active eIF2, whereas the genuine AUG codon can start translation following eIF2? inactivation. Collectively, our results suggest that SINV sgmRNA is translated by a scanning mechanism without the potential participation of crucial eIFs. A model is presented that explains the mechanism of initiation of mRNAs bearing two alternative initiation codons.
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Celiac symptoms in patients with fibromyalgia: a cross-sectional study.
Rheumatol. Int.
PUBLISHED: 08-15-2014
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Fibromyalgia is a chronic pain syndrome associated with numerous somatic symptoms including gastrointestinal manifestations of nonspecific nature. Celiac disease and nongluten sensitivity frequently evolve in adults with gastrointestinal and extraintestinal symptoms similar to those found among patients with fibromyalgia. The objective of the present study was to evaluate the presence of celiac-type symptoms among patients with fibromyalgia in comparison with healthy subjects and with those experienced by adult celiac patients and subjects with gluten sensitivity. A list of typical celiac-type symptoms was developed, comparing the frequency of presentation of these symptoms between patients with fibromyalgia (N = 178) and healthy subjects (N = 131), in addition to those of celiac patients and gluten-sensitive patients reported in the literature. The frequency of presentation of every celiac-type symptom, excepting anemia, was significantly higher among patients with fibromyalgia compared to controls (p < 0.0001). Regarding the existing data in the literature, the prevalence of fatigue, depression, cognitive symptoms and cutaneous lesions predominated among patients with fibromyalgia, whereas the prevalence of gastrointestinal symptoms was higher among patients with fibromyalgia compared to gluten-sensitive patients and was similar among patients with fibromyalgia and celiac disease patient. The symptomatological similarity of both pathologies, especially gastrointestinal symptoms, suggests that at least a subgroup of patients with fibromyalgia could experience subclinical celiac disease or nonceliac gluten intolerance.
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Direct Visualization of Fungal Infection in Brains from Patients with Alzheimer's Disease.
J. Alzheimers Dis.
PUBLISHED: 08-13-2014
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Recently, we have reported the presence of fungal infections in patients with Alzheimer's disease (AD). Accordingly, fungal proteins and DNA were found in brain samples, demonstrating the existence of infection in the central nervous system. In the present work, we raised antibodies to specific fungal species and performed immunohistochemistry to directly visualize fungal components inside neurons from AD patients. Mice infected with Candida glabrata were initially used to assess whether yeast can be internalized in mammalian tissues. Using polyclonal rabbit antibodies against C. glabrata, rounded immunopositive cells could be detected in the cytoplasm of cells from liver, spleen, and brain samples in infected, but not uninfected, mice. Immunohistochemical analyses of tissue from the frontal cortex of AD patients revealed the presence of fungal material in a small percentage (~10%) of cells, suggesting the presence of infection. Importantly, this immunopositive material was absent in control samples. Confocal microscopy indicated that this fungal material had an intracellular localization. The specific morphology of this material varied between patients; in some instances, disseminated material was localized to the cytoplasm, whereas small punctate bodies were detected in other patients. Interestingly, fungal material could be revealed using different anti-fungal antibodies, suggesting multiple infections. In summary, fungal infection can only be observed using specific anti-fungal antibodies and only a small percentage of cells contain fungi. Our findings provide an explanation for the hitherto elusive detection of fungi in AD brains, and are consistent with the idea that fungal cells are internalized inside neurons.
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L protease from foot and mouth disease virus confers eIF2-independent translation for mRNAs bearing picornavirus IRES.
FEBS Lett.
PUBLISHED: 07-28-2014
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The leader protease (L(pro)) from foot-and-mouth disease virus (FMDV) has the ability to cleave eIF4G, leading to a blockade of cellular protein synthesis. In contrast to previous reports, our present findings demonstrate that FMDV L(pro) is able to increase translation driven by FMDV IRES. Additionally, inactivation of eIF2 subsequent to phosphorylation induced by arsenite or thapsigargin in BHK cells blocks protein synthesis directed by FMDV IRES, whereas in the presence of L(pro), significant translation is found under these conditions. This phenomenon was also observed in cell-free systems after induction of eIF2 phosphorylation by addition of poly(I:C).
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Predictive tools for severe dengue conforming to World Health Organization 2009 criteria.
PLoS Negl Trop Dis
PUBLISHED: 07-01-2014
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Dengue causes 50 million infections per year, posing a large disease and economic burden in tropical and subtropical regions. Only a proportion of dengue cases require hospitalization, and predictive tools to triage dengue patients at greater risk of complications may optimize usage of limited healthcare resources. For severe dengue (SD), proposed by the World Health Organization (WHO) 2009 dengue guidelines, predictive tools are lacking.
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VALIDATION OF A VIDEO ANALYSIS SOFTWARE PACKAGE FOR QUANTIFYING MOVEMENT VELOCITY IN RESISTANCE EXERCISES.
J Strength Cond Res
PUBLISHED: 06-12-2014
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The aim of this study was to establish the validity of a video analysis software package in measuring mean propulsive velocity (MPV) and the maximal velocity during bench press. Twenty-one healthy males (21 ± 1 year) with weight training experience were recruited and the MPV and the maximal velocity of the concentric phase (Vmax) were compared to a linear position transducer system during a standard bench press exercise. Participants performed a one repetition maximum (1RM) test using the supine bench press exercise. The testing procedures involved the simultaneous assessment of bench press propulsive velocity using two kinematic (linear position transducer and semi-automated tracking software) systems. High Pearson´ correlation coefficients for MPV and Vmax between both devices (r = .473 to .993) were observed. The intraclass correlation coefficients (ICCs) for barbell velocity data and the kinematic data obtained from video analysis were high (>0.79). In addition, the low coefficients of variation indicate that measurements had low variability. Finally, Bland-Altman plots with the limits of agreement of the MPV and Vmax with different loads showed a negative trend which indicated that the video analysis had higher values than the linear transducer. In conclusion, this study has demonstrated that the software employed for the video analysis was an easy to use and cost-effective tool with a very high degree of concurrent validity. This software can be used to evaluate changes in velocity of raining load in resistance training which may be important for the prescription and monitoring of training programmes.
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Effects of a 10-week In-Season Eccentric Overload Training Program on Muscle Injury Prevention and Performance in Junior Elite Soccer Players.
Int J Sports Physiol Perform
PUBLISHED: 06-10-2014
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The aim of the current study was to analyse the effect of an eccentric overload training program (i.e., half squat and leg curl exercises using flywheel ergometers) with individualized load, on muscle injury incidence and severity, and performance in junior elite soccer players.
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Inhibition of host protein synthesis by Sindbis virus: correlation with viral RNA replication and release of nuclear proteins to the cytoplasm.
Cell. Microbiol.
PUBLISHED: 05-20-2014
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Infection of mammalian cells by Sindbis virus (SINV) profoundly blocks cellular mRNA translation. Experimental evidence points to viral non-structural proteins (nsPs), in particular nsP2, as the mediator of this inhibition. However, individual expression of nsP1, nsP2, nsP3 or nsP1-4 does not block cellular protein synthesis in BHK cells. Trans-complementation of a defective SINV replicon lacking most of the coding region for nsPs by the co-expression of nsP1-4 propitiates viral RNA replication at low levels, and inhibition of cellular translation is not observed. Exit of nuclear proteins including T-cell intracellular antigen and polypyrimidine tract-binding protein is clearly detected in SINV-infected cells, but not upon the expression of nsPs, even when the defective replicon was complemented. Analysis of a SINV variant with a point mutation in nsP2, exhibiting defects in the shut-off of host protein synthesis, indicates that both viral RNA replication and the release of nuclear proteins to the cytoplasm are greatly inhibited. Furthermore, nucleoside analogues that inhibit cellular and viral RNA synthesis impede the blockade of host mRNA translation, in addition to the release of nuclear proteins. Prevention of the shut-off of host mRNA translation by nucleoside analogues is not due to the inhibition of eIF2? phosphorylation, as this prevention is also observed in PKR(-/-) mouse embryonic fibroblasts that do not phosphorylate eIF2? after SINV infection. Collectively, our observations are consistent with the concept that for the inhibition of cellular protein synthesis to occur, viral RNA replication must take place at control levels, leading to the release of nuclear proteins to the cytoplasm.
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Fungal infection in patients with Alzheimer's disease.
J. Alzheimers Dis.
PUBLISHED: 03-12-2014
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Alzheimer's disease is a progressive neurodegenerative disorder that leads to dementia mainly among the elderly. This disease is characterized by the presence in the brain of amyloid plaques and neurofibrillary tangles that provoke neuronal cell death, vascular dysfunction, and inflammatory processes. In the present work, we have analyzed the existence of fungal infection in Alzheimer's disease patients. A proteomic analysis provides compelling evidence for the existence of fungal proteins in brain samples from Alzheimer's disease patients. Furthermore, PCR analysis reveals a variety of fungal species in these samples, dependent on the patient and the tissue tested. DNA sequencing demonstrated that several fungal species can be found in brain samples. Together, these results show that fungal macromolecules can be detected in brain from Alzheimer's disease patients. To our knowledge these findings represent the first evidence that fungal infection is detectable in brain samples from Alzheimer's disease patients. The possibility that this may represent a risk factor or may contribute to the etiological cause of Alzheimer's disease is discussed.
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Determination of methylmercury in marine biota samples: method validation.
Talanta
PUBLISHED: 01-20-2014
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Regulatory authorities are expected to measure concentration of contaminants in foodstuffs, but the simple determination of total amount cannot be sufficient for fully judging its impact on the human health. In particular, the methylation of metals generally increases their toxicity; therefore validated analytical methods producing reliable results for the assessment of methylated species are highly needed. Nowadays, there is no legal limit for methylmercury (MeHg) in food matrices. Hence, no standardized method for the determination of MeHg exists within the international jurisdiction. Contemplating the possibility of a future legislative limit, a method for low level determination of MeHg in marine biota matrixes, based on aqueous-phase ethylation followed by purge and trap and gas chromatography (GC) coupled to pyrolysis-atomic fluorescence spectrometry (Py-AFS) detection, has been developed and validated. Five different extraction procedures, namely acid and alkaline leaching assisted by microwave and conventional oven heating, as well as enzymatic digestion, were evaluated in terms of their efficiency to extract MeHg from Scallop soft tissue IAEA-452 Certified Reference Material. Alkaline extraction with 25% (w/w) KOH in methanol, microwave-assisted extraction (MAE) with 5M HCl and enzymatic digestion with protease XIV yielded the highest extraction recoveries. Standard addition or the introduction of a dilution step were successfully applied to overcome the matrix effects observed when microwave-assisted extraction using 25% (w/w) KOH in methanol or 25% (w/v) aqueous TMAH were used. ISO 17025 and Eurachem guidelines were followed to perform the validation of the methodology. Accordingly, blanks, selectivity, calibration curve, linearity (0.9995), working range (1-800pg), recovery (97%), precision, traceability, limit of detection (0.45pg), limit of quantification (0.85pg) and expanded uncertainty (15.86%, k=2) were assessed with Fish protein Dorm-3 Certified Reference Material. The major contributions to the expanded uncertainty, i.e. 86.1%, arose from the uncertainty associated with recovery, followed by the contribution from fluorescence signal. Additional validation of the methodology developed was effectuated by the comparison with the values reported for MeHg in the IAEA-452 inter-laboratory comparison exercise.
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Arabidopsis protein phosphatase DBP1 nucleates a protein network with a role in regulating plant defense.
PLoS ONE
PUBLISHED: 01-01-2014
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Arabidopsis thaliana DBP1 belongs to the plant-specific family of DNA-binding protein phosphatases. Although recently identified as a novel host factor mediating susceptibility to potyvirus, little is known about DBP1 targets and partners and the molecular mechanisms underlying its function. Analyzing changes in the phosphoproteome of a loss-of-function dbp1 mutant enabled the identification of 14-3-3? isoform (GRF6), a previously reported DBP1 interactor, and MAP kinase (MAPK) MPK11 as components of a small protein network nucleated by DBP1, in which GRF6 stability is modulated by MPK11 through phosphorylation, while DBP1 in turn negatively regulates MPK11 activity. Interestingly, grf6 and mpk11 loss-of-function mutants showed altered response to infection by the potyvirus Plum pox virus (PPV), and the described molecular mechanism controlling GRF6 stability was recapitulated upon PPV infection. These results not only contribute to a better knowledge of the biology of DBP factors, but also of MAPK signalling in plants, with the identification of GRF6 as a likely MPK11 substrate and of DBP1 as a protein phosphatase regulating MPK11 activity, and unveils the implication of this protein module in the response to PPV infection in Arabidopsis.
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Identification of transcription factors potentially involved in the juvenile to adult phase transition in Citrus.
Ann. Bot.
PUBLISHED: 09-19-2013
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The juvenile to adult transition (JAT) in higher plants is required for them to reach reproductive competence. However, it is a poorly understood process in woody plants, where only a few genes have been definitely identified as being involved in this transition. This work aims at increasing our understanding of the mechanisms regulating the JAT in citrus.
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Changes in body balance and functional performance following whole-body vibration training in patients with fibromyalgia syndrome: a randomized controlled trial.
J Rehabil Med
PUBLISHED: 07-06-2013
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To determine whether an 8-week exercise programme supplemented with whole-body vibration improves body balance and dynamic strength in women with fibromyalgia.
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Trends in parameterization, economics and host behaviour in influenza pandemic modelling: a review and reporting protocol.
Emerg Themes Epidemiol
PUBLISHED: 04-26-2013
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The volume of influenza pandemic modelling studies has increased dramatically in the last decade. Many models incorporate now sophisticated parameterization and validation techniques, economic analyses and the behaviour of individuals.
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[Contributions of cortisol suppression tests to understanding of psychiatric disorders: a narrative review of literature].
Endocrinol Nutr
PUBLISHED: 04-25-2013
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Activity of the hypothalamic-pituitary-adrenal axis had been studied for the past half century, when some researchers noted that some patients with Cushings syndrome and severe mood disorders had high baseline cortisol levels, which resulted in an inhibited response in the 1mg dexamethasone suppression test. Altered dexamethasone suppression test results were subsequently found in many psychiatric diseases, including anorexia nervosa, obsessive-compulsive disorder, degenerative dementia, bipolar disorders, and schizophrenia. The relationship between high baseline cortisol levels and stress has also been studied. Some researches on the genesis of borderline personality disorder focused on traumatic childhood backgrounds. Other investigations aimed at elucidating the relationship between traumatic backgrounds and some psychiatric disorders noted that patients with post-traumatic stress disorder and borderline personality disorder showed an enhanced cortisol suppression with low cortisol doses (0.5 mg). Recent studies showed that use of an ultra-low dose of cortisol during the dexamethasone suppression test may be helpful for detecting disorders with hyperactivity of the hypothalamic-pituitary-adrenal axis. Recent advances in neuroimaging support the existence of hyperactivity of the hypothalamic-pituitary-adrenal axis in patients with borderline personality disorder, relating a decreased pituitary gland volume to major traumatic backgrounds and suicidal attempts. The purpose of this paper is to make a narrative review of research using dexamethasone suppression test in psychiatric disorders, in order to ascertain its value as a supplemental diagnostic test or as a prognostic marker.
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Agricultural intensification escalates future conservation costs.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 04-15-2013
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The supposition that agricultural intensification results in land sparing for conservation has become central to policy formulations across the tropics. However, underlying assumptions remain uncertain and have been little explored in the context of conservation incentive schemes such as policies for Reducing Emissions from Deforestation and forest Degradation, conservation, sustainable management, and enhancement of carbon stocks (REDD+). Incipient REDD+ forest carbon policies in a number of countries propose agricultural intensification measures to replace extensive "slash-and-burn" farming systems. These may result in conservation in some contexts, but will also increase future agricultural land rents as productivity increases, creating new incentives for agricultural expansion and deforestation. While robust governance can help to ensure land sparing, we propose that conservation incentives will also have to increase over time, tracking future agricultural land rents, which might lead to runaway conservation costs. We present a conceptual framework that depicts these relationships, supported by an illustrative model of the intensification of key crops in the Democratic Republic of Congo, a leading REDD+ country. A von Thünen land rent model is combined with geographic information systems mapping to demonstrate how agricultural intensification could influence future conservation costs. Once postintensification agricultural land rents are considered, the cost of reducing forest sector emissions could significantly exceed current and projected carbon credit prices. Our analysis highlights the importance of considering escalating conservation costs from agricultural intensification when designing conservation initiatives.
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Inflammatory activation and cholinergic anti-inflammatory system in eating disorders.
Brain Behav. Immun.
PUBLISHED: 04-08-2013
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Dysfunctional serotoninergic regulation and hypothalamic-pituitary-adrenal (HPA) axis overreactivity have been consistently reported in research studies with eating disorders (ED). In addition, the links between stress response, serotonin function, HPA axis and inflammatory mechanisms in ED have also been suggested in a number of studies. In our study, inflammatory parameters in white blood cells were investigated in 26 female patients with ED and 25 healthy control subjects matched for sex, age and ethnicity. Patients were free of medication for at least two weeks at the time of the study. Results showed a significant increase in plasma levels of the proinflammatory cytokine IL1? and the protein expression of cyclooxygenase 2 (COX2) in peripheral mononuclear blood cells (PMBCs) in ED patients compared with controls. As well as a significant increase of the oxidative-nitrosative marker TBARS (Thiobarbituric Acid Reactive Substances) in plasma. These findings were associated with increased expression of the alpha7 subunit of the nicotinic receptor (?7nAChR) in PMBC in ED patients independent of plasma cotinine levels. These results suggest that a pro-inflammatory and oxidant phenotype might be present in ED patients. Further research on cellular inflammatory and anti-inflammatory pathways might be oriented to investigate differences between ED subtypes and to search for new potential targets for pharmacological treatment.
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Translation of viral mRNAs that do not require eIF4E is blocked by the inhibitor 4EGI-1.
Virology
PUBLISHED: 03-23-2013
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High throughput screening has rendered new inhibitors of eukaryotic protein synthesis. One such molecule, 4EGI-1 has been reported to selectively block the initiation factor eIF4E. We have investigated the action of this inhibitor on translation directed by several viral mRNAs which, in principle, do not utilize eIF4E. We found that 4EGI-1 inhibits translation directed by poliovirus IRES, in rabbit reticulocyte lysates, to a similar extent as capped mRNA. Moreover, 4EGI-1 inhibits translation driven by poliovirus IRES, both in vitro and in cultured cells, despite cleavage of eIF4G by picornavirus proteases. Finally, translation of vesicular stomatitis virus mRNAs and Sindbis virus subgenomic mRNA is blocked by 4EGI-1 in infected cells to a similar extent as cellular mRNAs. These findings cast doubt on the selective action of this inhibitor, and suggest that this molecule may affect other steps in protein synthesis unrelated to cap recognition by eIF4E.
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A synthetic peptide from transforming growth factor-?? type III receptor inhibits NADPH oxidase and prevents oxidative stress in the kidney of spontaneously hypertensive rats.
Antioxid. Redox Signal.
PUBLISHED: 03-18-2013
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The NADPH oxidases constitute a major source of superoxide anion (·O2(-)) in hypertension. Several studies suggest an important role of NADPH oxidases in different effects mediated by transforming growth factor-?? (TGF-??). We investigated whether a chronic treatment with P144, a peptide synthesized from type III TGF-?? receptor, inhibited NADPH oxidases in the renal cortex of spontaneously hypertensive rats (SHR).
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Impact of an acute bout of vibration on muscle contractile properties, creatine kinase and lactate dehydrogenase response.
Eur J Sport Sci
PUBLISHED: 03-11-2013
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Abstract The aim of this study was to assess the effects of a bout of whole body vibration (WBV) on muscle response and to determine whether this stimulus leads to muscle damage. Thirty healthy and physically active participants (mean±SD; age: 21.8±2.0 years; height: 176.7±5.8 cm; body mass: 76±6.8 kg and BMI: 23.1±3.7 kg·m(-2)) participated in this study. Participants were randomly allocated in one of two groups, one of them performed a bout of 360 s WBV (frequency: 30 Hz; peak-to-peak displacement: 4 mm) (VIB) and the other one adopted a sham position (CON). Muscle contractile properties were analysed in the rectus femoris (RF) by using tensiomyography (TMG) 2 min before the warm-up and 2 min after intervention. Muscle damage was assessed by determining plasma creatine kinase (CK) and lactate dehydrogenase (LDH) levels at three time points; 5 min before warm-up and 1 h and 48 h after the intervention. TMG results showed a significant decrease in maximal displacement (p<0.05) and delay time (p<0.05) in VIB and in delay time (p<0.05) and relaxation time (p<0.05) in CON. Muscle damage markers showed significant group differences (p<0.05) for CK 1 h after the intervention. In addition, differences for CK 1 h after the intervention from baseline (p<0.05) were also observed in VIB. In conclusion, a 6-min bout of WBV results in an increase of muscle stiffness in RF and increased CK levels 1 h after intervention (returning to baseline within 48 h).
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Who should pay for global health, and how much?
PLoS Med.
PUBLISHED: 02-19-2013
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Roman Carrasco and colleagues propose a "cap and trade" system for global health involving a cost-effectiveness criterion and a DALY global credit market, mirroring global carbon emission permits trading markets to mitigate climate change.
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Participation of eIF4F complex in Junin virus infection: blockage of eIF4E does not impair virus replication.
Cell. Microbiol.
PUBLISHED: 01-21-2013
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Translation efficiency of viral mRNAs is a key factor defining both cytopathogenicity and virulence of viruses, which are entirely dependent on the cellular translation machinery to synthesize their proteins. This dependence has led them to develop different translational reprogramming strategies to ensure viral mRNAs can effectively compete with cellular mRNAs. Junin virus (JUNV) is a member of the family Arenaviridae, whose mRNAs are capped but not polyadenylated. In this work we evaluated the relevance to JUNV replication of the main components of the eIF4F complex: eIF4A, eIF4GI and eIF4E. We found the viral nucleoprotein (N) of JUNV colocalized with eIF4A and eIF4GI but not with eIF4E. Moreover, N could be immunoprecipitated in association with eIF4A and eIF4GI but not with eIF4E. Accordingly, functional impairment of eIF4A as well as eIF4GI reduced JUNV multiplication. By contrast, inhibition of eIF4E did not show a significant effect on JUNV protein synthesis. A similar situation was observed for another two members of arenaviruses: Tacaribe (TCRV) and Pichinde (PICV) viruses. Finally, the nucleoproteins of JUNV, TCRV and PICV were able to interact with 7 methyl-guanosine (cap), suggesting that the independence of JUNV multiplication on eIF4E, the cap-binding protein, may be due to the replacement of this factor by N protein.
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Safety and cost savings of reducing adult dengue hospitalization in a tertiary care hospital in Singapore.
Trans. R. Soc. Trop. Med. Hyg.
PUBLISHED: 01-09-2013
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Previously, most dengue cases in Singapore were hospitalized despite low incidence of dengue hemorrhagic fever (DHF) or death. To minimize hospitalization, the Communicable Disease Centre at Tan Tock Seng Hospital (TTSH) in Singapore implemented new admission criteria which included clinical, laboratory, and DHF predictive parameters in 2007.
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Poliovirus 2A protease triggers a selective nucleo-cytoplasmic redistribution of splicing factors to regulate alternative pre-mRNA splicing.
PLoS ONE
PUBLISHED: 01-01-2013
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Poliovirus protease 2A (2A(pro)) obstructs host gene expression by reprogramming transcriptional and post-transcriptional regulatory events during infection. Here we demonstrate that expression of 2A(pro) induces a selective nucleo-cytoplasm translocation of several important RNA binding proteins and splicing factors. Subcellular fractionation studies, together with immunofluorescence microscopy revealed an asymmetric distribution of HuR and TIA1/TIAR in 2A(pro) expressing cells, which modulates splicing of the human Fas exon 6. Consistent with this result, knockdown of HuR or overexpression of TIA1/TIAR, leads to Fas exon 6 inclusion in 2A(pro)-expressing cells. Therefore, poliovirus 2A(pro) can target alternative pre-mRNA splicing by regulating protein shuttling between the nucleus and the cytoplasm.
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Economic and environmental impacts of harmful non-indigenous species in southeast Asia.
PLoS ONE
PUBLISHED: 01-01-2013
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Harmful non-indigenous species (NIS) impose great economic and environmental impacts globally, but little is known about their impacts in Southeast Asia. Lack of knowledge of the magnitude of the problem hinders the allocation of appropriate resources for NIS prevention and management. We used benefit-cost analysis embedded in a Monte-Carlo simulation model and analysed economic and environmental impacts of NIS in the region to estimate the total burden of NIS in Southeast Asia. The total annual loss caused by NIS to agriculture, human health and the environment in Southeast Asia is estimated to be US$33.5 billion (5(th) and 95(th) percentile US$25.8-39.8 billion). Losses and costs to the agricultural sector are estimated to be nearly 90% of the total (US$23.4-33.9 billion), while the annual costs associated with human health and the environment are US$1.85 billion (US$1.4-2.5 billion) and US$2.1 billion (US$0.9-3.3 billion), respectively, although these estimates are based on conservative assumptions. We demonstrate that the economic and environmental impacts of NIS in low and middle-income regions can be considerable and that further measures, such as the adoption of regional risk assessment protocols to inform decisions on prevention and control of NIS in Southeast Asia, could be beneficial.
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Determining the optimal whole-body vibration dose-response relationship for muscle performance.
J Strength Cond Res
PUBLISHED: 11-15-2011
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Da Silva-Grigoletto, ME, de Hoyo, M, Sañudo, B, Corrales, L, and García-Manso, JM. Determining the optimal whole-body vibration dose-response relationship for muscle performance. J Strength Cond Res 25(12): 3326-3333, 2011-The aim of this investigation was twofold: first, to determine the optimal duration of a single whole-body vibration (WBV) exposure (phase 1) and second to find out the ideal number of sets per intervention to maximize muscle performance (phase 2). All participants were young (age: 19.4 ± 1.6 years), healthy, physically active men. In both studies, a 30-Hz frequency and a 4-mm peak-to-peak displacement were used. In phase 1, subjects (n = 30) underwent 3 sets of different durations (30, 60, and 90 seconds), whereas in phase 2, subjects (n = 27) underwent 3 interventions where the duration remained fixed at 60 seconds, and the number of sets performed (3, 6, or 9) was modified. The recovery time between sets was set at 2 minutes. In all interventions, each set consisted of 1 isometric repetition in a squat position with knees flexed at 100°. Before and after each session, jump height (countermovement jump [CMJ] and squat jump [SJ]) and power output in half squat (90° knee flexion) were assessed. In phase 1, an improvement in jump ability and power output was observed after the 30- and 60-second intervention (p < 0.01), whereas the 90 second intervention, participants just experienced a decrease in SJ and CMJ (p < 0.05). When comparing the different protocols, the greatest response was achieved using 60 seconds (p < 0.05), which was therefore considered as the optimal duration to be used in phase 2. In the second phase, improvements in jump ability and power output were found with 3 and 6 sets (p < 0.05), whereas with 9 sets, participants actually experienced a decrease in these variables. Intergroup comparison showed a greater effect for the program of 6 sets (p < 0.05). In conclusion, a WBV intervention consisting of six 60-second sets produces improved muscle performance measured by SJ, CMJ, and power output.
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A plant small polypeptide is a novel component of DNA-binding protein phosphatase 1-mediated resistance to plum pox virus in Arabidopsis.
Plant Physiol.
PUBLISHED: 10-20-2011
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DNA-binding protein phosphatases (DBPs) have been identified as a novel class of plant-specific regulatory factors playing a role in plant-virus interactions. NtDBP1 from tobacco (Nicotiana tabacum) was shown to participate in transcriptional regulation of gene expression in response to virus infection in compatible interactions, and AtDBP1, its closest relative in the model plant Arabidopsis (Arabidopsis thaliana), has recently been found to mediate susceptibility to potyvirus, one of the most speciose taxa of plant viruses. Here, we report on the identification of a novel family of highly conserved small polypeptides that interact with DBP1 proteins both in tobacco and Arabidopsis, which we have designated DBP-interacting protein 2 (DIP2). The interaction of AtDIP2 with AtDBP1 was demonstrated in vivo by bimolecular fluorescence complementation, and AtDIP2 was shown to functionally interfere with AtDBP1 in yeast. Furthermore, reducing AtDIP2 gene expression leads to increased susceptibility to the potyvirus Plum pox virus and to a lesser extent also to Turnip mosaic virus, whereas overexpression results in enhanced resistance. Therefore, we describe a novel family of conserved small polypeptides in plants and identify AtDIP2 as a novel host factor contributing to resistance to potyvirus in Arabidopsis.
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A non-infectious cell-based phenotypic assay for the assessment of HIV-1 susceptibility to protease inhibitors.
J. Antimicrob. Chemother.
PUBLISHED: 10-12-2011
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HIV-1 genotyping is widely accepted as a diagnostic tool to optimize therapy changes in patients whose antiretroviral regimen is failing. Phenotyping can substantially complement the information obtained from genotyping, especially in the presence of complex mutational patterns. However, drug susceptibility tests are laborious and require biosafety facilities. We describe the molecular mechanism of a non-infectious HIV-1 protease phenotypic assay in eukaryotic cells and validate its applicability as a tool for monitoring drug resistance.
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Alternative splicing, a new target to block cellular gene expression by poliovirus 2A protease.
Biochem. Biophys. Res. Commun.
PUBLISHED: 08-24-2011
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Viruses have developed multiple strategies to interfere with the gene expression of host cells at different stages to ensure their own survival. Here we report a new role for poliovirus 2A(pro) modulating the alternative splicing of pre-mRNAs. Expression of 2A(pro) potently inhibits splicing of reporter genes in HeLa cells. Low amounts of 2A(pro) abrogate Fas exon 6 skipping, whereas higher levels of protease fully abolish Fas and FGFR2 splicing. In vitro splicing of MINX mRNA using nuclear extracts is also strongly inhibited by 2A(pro), leading to accumulation of the first exon and the lariat product containing the unspliced second exon. These findings reveal that the mechanism of action of 2A(pro) on splicing is to selectively block the second catalytic step.
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Membrane integration of poliovirus 2B viroporin.
J. Virol.
PUBLISHED: 08-10-2011
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Virus infections can result in a variety of cellular injuries, and these often involve the permeabilization of host membranes by viral proteins of the viroporin family. Prototypical viroporin 2B is responsible for the alterations in host cell membrane permeability that take place in enterovirus-infected cells. 2B protein can be localized at the endoplasmic reticulum (ER) and the Golgi complex, inducing membrane remodeling and the blockade of glycoprotein trafficking. These findings suggest that 2B has the potential to integrate into the ER membrane, but specific information regarding its biogenesis and mechanism of membrane insertion is lacking. Here, we report experimental results of in vitro translation-glycosylation compatible with the translocon-mediated insertion of the 2B product into the ER membrane as a double-spanning integral membrane protein with an N-/C-terminal cytoplasmic orientation. A similar topology was found when 2B was synthesized in cultured cells. In addition, the in vitro translation of several truncated versions of the 2B protein suggests that the two hydrophobic regions cooperate to insert into the ER-derived microsomal membranes.
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Translation without eIF2 promoted by poliovirus 2A protease.
PLoS ONE
PUBLISHED: 07-05-2011
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Poliovirus RNA utilizes eIF2 for the initiation of translation in cell free systems. Remarkably, we now describe that poliovirus translation takes place at late times of infection when eIF2 is inactivated by phosphorylation. By contrast, translation directed by poliovirus RNA is blocked when eIF2 is inactivated at earlier times. Thus, poliovirus RNA translation exhibits a dual mechanism for the initiation of protein synthesis as regards to the requirement for eIF2. Analysis of individual poliovirus non-structural proteins indicates that the presence of 2A(pro) alone is sufficient to provide eIF2 independence for IRES-driven translation. This effect is not observed with a 2A(pro) variant unable to cleave eIF4G. The level of 2A(pro) synthesized in culture cells is crucial for obtaining eIF2 independence. Expression of the N-or C-terminus fragments of eIF4G did not stimulate IRES-driven translation, nor provide eIF2 independence, consistent with the idea that the presence of 2A(pro) at high concentrations is necessary. The finding that 2A(pro) provides eIF2-independent translation opens a new and unsuspected area of research in the field of picornavirus protein synthesis.
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Economic impact of dengue illness and the cost-effectiveness of future vaccination programs in Singapore.
PLoS Negl Trop Dis
PUBLISHED: 06-21-2011
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Dengue illness causes 50-100 million infections worldwide and threatens 2.5 billion people in the tropical and subtropical regions. Little is known about the disease burden and economic impact of dengue in higher resourced countries or the cost-effectiveness of potential dengue vaccines in such settings.
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The A640G CYBA polymorphism associates with subclinical atherosclerosis in diabetes.
Front Biosci (Elite Ed)
PUBLISHED: 05-31-2011
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Oxidative stress is implicated in diabetes. The NADPH oxidases are the main source of superoxide in phagocytic and vascular cells, and p22phox is a key subunit. Genetic variants of CYBA, the human p22phox gene, associate with cardiovascular disease. We investigated the association of the A640G polymorphism with diabetes and its impact on phagocytic NADPH oxidase-dependent superoxide production and subclinical atherosclerosis. We studied 1212 subjects in which clinical parameters including carotid intima-media thickness (cIMT) were assessed. The A640G polymorphism was genotyped by TaqMan probes. In 496 subjects, the NADPH oxidase-dependent superoxide production in peripheral blood mononuclear cells was assessed by chemiluminescence. The GG genotype prevalence was significantly higher in type 2 diabetic patients than in non-diabetic subjects. Peripheral blood mononuclear cells from diabetic GG patients presented higher NADPH oxidase-dependent superoxide production than those of diabetic AA/AG patients. Within the diabetic group, GG patients presented higher cIMT levels than AA/AG patients. The A640G CYBA polymorphism may be a marker of oxidative stress risk and may be indicative of subclinical atherosclerosis in type 2 diabetes.
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Prospective validation of two models for ultrasonographic diagnosis of cirrhosis.
Rev Esp Enferm Dig
PUBLISHED: 05-31-2011
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To perform a prospective validation and comparative analysis of two ultrasonographic diagnostic scores of cirrhosis in patients with silent liver disease.
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Psychological factors affecting response to antidepressant drugs in fibromyalgia.
Psychosomatics
PUBLISHED: 05-14-2011
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The use of antidepressant drugs in fibromyalgia is extensive despite small evidence of the real impact in the clinical practice setting. This study was aimed to evaluate the long-term efficiency of antidepressant treatment in fibromyalgia and the role of psychosocial factors in treatment response.
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Methylmercury levels and bioaccumulation in the aquatic food web of a highly mercury-contaminated reservoir.
Environ Int
PUBLISHED: 05-05-2011
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The low Ebro River basin (NE Spain) represents a particular case of chronic and long-term mercury pollution due to the presence of an industrial waste (up to 436 ?g/g of Hg) coming from a chlor-alkali plant Albeit high total mercury (THg) levels have been previously described in several aquatic species from the surveyed area, methylmercury (MeHg) values in fish individuals have never been reported. Accordingly, in order to investigate bioaccumulation patterns at different levels of the aquatic food web of such polluted area, crayfish and various fish species, were analysed for THg and MeHg content. At the hot spot, THg mean values of crayfish muscle tissue and hepatopancreas were 10 and 15 times, respectively, greater than the local background level. Higher mean THg concentrations were detected in piscivorous (THg=0.848 ± 0.476 ?g/g wet weight (ww); MeHg=0.672 ± 0.364 ?g/g ww) than in non-piscivorous fish (THg=0.305 ± 0.163 ?g/g ww; MeHg=0.278 ± 0.239 ?g/g ww). Although these results indicated that THg in fish increased significantly with increasing trophic position, the percentage of the methylated form of Hg was not strongly influenced by differences in relative trophic position. This is an important finding, since the fraction of THg as MeHg in the top fish predator was unexpectedly lower than for other species of the aquatic food chain. Moreover, mean THg concentrations in piscivorous fish exceed the maximum level recommended for human consumption. From our findings, it is clear that for this specific polluted system, speciation becomes almost mandatory when risk assessment is based on MeHg, since single measurements of THg are inadequate and could lead to an over- or under-estimation of contamination levels.
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Effects of a prolonged exercise program on key health outcomes in women with fibromyalgia: a randomized controlled trial.
J Rehabil Med
PUBLISHED: 05-03-2011
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To assess the impact of a long-term exercise programme vs usual care on perceived health status, functional capacity and depression in patients with fibromyalgia.
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Patterns of mercury and methylmercury bioaccumulation in fish species downstream of a long-term mercury-contaminated site in the lower Ebro River (NE Spain).
Chemosphere
PUBLISHED: 04-18-2011
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Since the 19th century, large amounts of industrial waste were dumped in a reservoir adjacent to a chlor-alkali plant in the lower Ebro River (NE Spain). Previous toxicological analysis of carp populations inhabiting the surveyed area have shown that the highest biological impact attributable to mercury pollution occurred downstream of the discharge site. However, mercury speciation in fish from this polluted area has not been addressed yet. Thus, in the present study, piscivorous European catfish (Silurus glanis) and non-piscivorous common carp (Cyprinus carpio) were selected, to investigate the bioavailability and bioaccumulation capacities of both total mercury (THg) and methylmercury (MeHg) at the discharge site and downstream points. Multiple Correspondence Analysis (MCA) was applied to reduce the dimensionality of the data set, and Multiple Linear Regression (MLR) models were fitted in order to assess the relationship between both Hg species in fish and different variables of interest. Mercury levels in fish inhabiting the dam at the discharge site were found to be approximately 2-fold higher than those from an upstream site; while mercury pollution progressively increased downstream of the hot spot. In fact, both THg and MeHg levels at the farthest downstream point were 3 times greater than those close to the waste dump. This result clearly indicates downstream transport and increased mercury bioavailability as a function of distance downstream from the contamination source. A number of factors may affect both the downstream transport and increased Hg bioavailability associated with suspended particulate matter (SPM) and dissolved organic carbon (DOC).
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[One-step nucleic acid amplification (OSNA) assay for sentinel lymph node metastases as an alternative to conventional postoperative histology in breast cancer: A cost-benefit analysis].
Cir Esp
PUBLISHED: 04-05-2011
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Intraoperative molecular analysis for sentinel lymph node (SLN) metastases using the OSNA (one-step nucleic acid amplification) method has been already validated in breast cancer. The authors compared the cost of OSNA versus the conventional postoperative histopathologic evaluation in patients with breast cancer.
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Translation of viral mRNA without active eIF2: the case of picornaviruses.
PLoS ONE
PUBLISHED: 03-18-2011
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Previous work by several laboratories has established that translation of picornavirus RNA requires active eIF2? for translation in cell free systems or after transfection in culture cells. Strikingly, we have found that encephalomyocarditis virus protein synthesis at late infection times is resistant to inhibitors that induce the phosphorylation of eIF2? whereas translation of encephalomyocarditis virus early during infection is blocked upon inactivation of eIF2? by phosphorylation induced by arsenite. The presence of this compound during the first hour of infection leads to a delay in the appearance of late protein synthesis in encephalomyocarditis virus-infected cells. Depletion of eIF2? also provokes a delay in the kinetics of encephalomyocarditis virus protein synthesis, whereas at late times the levels of viral translation are similar in control or eIF2?-depleted HeLa cells. Immunofluorescence analysis reveals that eIF2?, contrary to eIF4GI, does not colocalize with ribosomes or with encephalomyocarditis virus 3D polymerase. Taken together, these findings support the novel idea that eIF2 is not involved in the translation of encephalomyocarditis virus RNA during late infection. Moreover, other picornaviruses such as foot-and-mouth disease virus, mengovirus and poliovirus do not require active eIF2? when maximal viral translation is taking place. Therefore, translation of picornavirus RNA may exhibit a dual mechanism as regards the participation of eIF2. This factor would be necessary to translate the input genomic RNA, but after viral RNA replication, the mechanism of viral RNA translation switches to one independent of eIF2.
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Functional impairment of eIF4A and eIF4G factors correlates with inhibition of influenza virus mRNA translation.
Virology
PUBLISHED: 02-09-2011
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Influenza virus mRNAs contain a 5-cap structure followed by short cell-derived heterogeneous oligonucleotides and they are polyadenylated. However, selective translation of viral mRNAs occurs upon infection. Thus, we have studied whether differential requirements for the eIF4F components on viral and cellular translation could mediate this selectivity. We have previously reported that influenza virus infection proceeds efficiently upon functional impairment of the cap-binding factor eIF4E. Now, the requirements for the eIF4A helicase and the eIF4G scaffolding factor have been examined. The two proteins are essential for viral translation both in in vivo and in vitro analysis. Consequently, viral mRNAs do not contain cis-acting signals that could mediate eIF4A and eIF4G independence and trans-acting viral proteins do not replace their function. Thus, eIF4A and eIF4G proteins are not responsible for the selective translation of viral mRNAs and the translational shut-off of cellular protein synthesis observed in influenza virus infected cells.
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Strategies for antiviral stockpiling for future influenza pandemics: a global epidemic-economic perspective.
J R Soc Interface
PUBLISHED: 02-04-2011
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Influenza pandemics present a global threat owing to their potential mortality and substantial economic impacts. Stockpiling antiviral drugs to manage a pandemic is an effective strategy to offset their negative impacts; however, little is known about the long-term optimal size of the stockpile under uncertainty and the characteristics of different countries. Using an epidemic-economic model we studied the effect on total mortality and costs of antiviral stockpile sizes for Brazil, China, Guatemala, India, Indonesia, New Zealand, Singapore, the UK, the USA and Zimbabwe. In the model, antivirals stockpiling considerably reduced mortality. There was greater potential avoidance of expected costs in the higher resourced countries (e.g. from $55 billion to $27 billion over a 30 year time horizon for the USA) and large avoidance of fatalities in those less resourced (e.g. from 11.4 to 2.3 million in Indonesia). Under perfect allocation, higher resourced countries should aim to store antiviral stockpiles able to cover at least 15 per cent of their population, rising to 25 per cent with 30 per cent misallocation, to minimize fatalities and economic costs. Stockpiling is estimated not to be cost-effective for two-thirds of the worlds population under current antivirals pricing. Lower prices and international cooperation are necessary to make the life-saving potential of antivirals cost-effective in resource-limited countries.
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Effectiveness of low-frequency vibration recovery method on blood lactate removal, muscle contractile properties and on time to exhaustion during cycling at VO?max power output.
Eur. J. Appl. Physiol.
PUBLISHED: 01-20-2011
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The aim of the study was to determine the effectiveness of low-frequency vibration recovery (LFV-rec) on blood lactate removal, muscle contractile properties, and on time to exhaustion during cycling at maximal oxygen uptake power output (pVO(2max)). Twelve active males carried out three experimental sessions. In session 1, participants maximal oxygen uptake (VO(2max)) and pVO(2max) were determined, and in sessions 2 and 3, the participants performed a fatiguing exercise (2 min of cycling at pVO(2max)) and then a 15 min recovery period using one of two different methods: LFV-rec which consisted on sitting with feet on the vibratory platform (20 Hz; 4 mm) and passive recovery (P-rec), sitting without vibration stimulus. After that, participants performed an all-out exercise test on cycle ergometer at pVO(2max). In the recovery period, variables such as heart rate (HR), blood lactate concentration [Lac], and tensiomyographic parameters (D (m): maximal radial displacement; T (s): time of contraction maintenance, and T (r): relaxation time) were measured. In an all-out exercise test, mean time to exhaustion (TTE), total distance covered (TD), mean cycling velocity (V (m)), and maximal HR (HR(max)) were also assessed. The results showed no effect of recovery strategy on any of the assessed variables; nevertheless, higher values, although not significant, were observed in TTE, TD, and V (m) after LFV-rec intervention. In conclusion, LFV-rec strategy applied during 15 min after short and intense exercise does not seem to be effective on blood lactate removal, muscle contractile properties, and on time to exhaustion during cycling at pVO(2max).
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The multifaceted poliovirus 2A protease: regulation of gene expression by picornavirus proteases.
J. Biomed. Biotechnol.
PUBLISHED: 01-18-2011
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After entry into animal cells, most viruses hijack essential components involved in gene expression. This is the case of poliovirus, which abrogates cellular translation soon after virus internalization. Abrogation is achieved by cleavage of both eIF4GI and eIF4GII by the viral protease 2A. Apart from the interference of poliovirus with cellular protein synthesis, other gene expression steps such as RNA and protein trafficking between nucleus and cytoplasm are also altered. Poliovirus 2A(pro) is capable of hydrolyzing components of the nuclear pore, thus preventing an efficient antiviral response by the host cell. Here, we compare in detail poliovirus 2A(pro) with other viral proteins (from picornaviruses and unrelated families) as regard to their activity on key host factors that control gene expression. It is possible that future analyses to determine the cellular proteins targeted by 2A(pro) will uncover other cellular functions ablated by poliovirus infection. Further understanding of the cellular proteins hydrolyzed by 2A(pro) will add further insight into the molecular mechanism by which poliovirus and other viruses interact with the host cell.
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Subchronic effects of cyanobacterial cells on the transcription of antioxidant enzyme genes in tilapia (Oreochromis niloticus).
Ecotoxicology
PUBLISHED: 01-14-2011
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The increasing occurrence of toxic cyanobacterial blooms in eutrophic water bodies is nowadays of worldwide concern due to their ability to produce toxins such as microcystins (MCs). These cyanobacterial toxins have been shown to affect aquatic organisms such as fish, resulting in oxidative stress. Among the antioxidant enzymes, glutathione peroxidase (GPx) and soluble glutathione-S-transferases (sGST) play an important role in the detoxification of MCs. In the present work tilapia (Oreochromis niloticus) were orally exposed to cyanobacterial cells containing MCs and non-containing MCs for 21 days. The activity and relative mRNA expression by real-time PCR of both enzymes and the GST protein abundance by Western blot analysis were evaluated in liver and kidney. Also the induction of lipid peroxidation (LPO) was assayed. MCs containing cyanobacterial cells induced an increase of LPO products in both organs, and MCs containing and MCs non-containing cyanobacterial cells altered the activity, gene expression and protein abundance of the enzymes, indicating the importance of GPx and sGST in MCs detoxification. Moreover, liver, the main organ involved in biodegradation and biotransformation, experienced an adaptative response to the toxic insult. These results show for the first time that the subchronic exposure to cyanobacterial cells causes changes in antioxidant and detoxification enzymes and that GPx and GST gene expression are good markers of these alterations in tilapia.
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Practicing exorcism in schizophrenia.
BMJ Case Rep
PUBLISHED: 01-01-2011
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Historically, many cases of demonic possession have masked major psychiatric disorder. Our aim is to increase awareness that symptoms of schizophrenia are still being classified as demonic possession by priests today. We report the case of a 28-year-old patient who had been diagnosed 5 years previously with paranoid schizophrenia (treated with clozapine, risperidone, ziprasidone and onlanzapine without a complete response) and was also receiving treatment in a first episode psychosis unit in Spain. The patient was led to believe by priests that her psychotic symptoms were due to the presence of a demon. This was surprising because some of the priests were from the Madrid archdiocese and knew the clinical situation of the patient; however, they believed that she was suffering from demonic possession, and she underwent multiple exorcisms, disrupting response to clinical treatment. Patient insight is an important factor in response to treatment, so religious professionals should encourage appropriate psychiatric treatment and learn about mental illnesses.
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Nitric oxide involved in the IL-1?-induced inhibition of fructose intestinal transport.
J. Cell. Biochem.
PUBLISHED: 08-31-2010
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Interleukin-1? (IL-1?) is a pleiotropic cytokine produced by cells of the immune system and a large variety of other cell types including endothelial cells. It is released during inflammatory and infectious diseases, and possesses a wide spectrum of autocrine, paracrine and endocrine activities. The aim of this work was to examine the IL-1? effect on D-fructose transport across rabbit jejunum and try to identify the mediators implicated in this process. A sepsis condition was induced for 90 min after intravenous (iv) administration of IL-1? and body temperature was recorded. Studies on cellular intestinal integrity have not shown modifications of the epithelium and the basement membrane. D-fructose intestinal transport was studied in rabbit jejunum from control and treated animals and it was reduced in the latter ones. This cytokine decreased both the mucosal to serosal transepithelial flux and the transport across brush-border membrane vesicles of D-fructose. The inhibition was reversed by L-NAME (nitric oxide [NO] synthase inhibitor), but not by indomethacin (cyclooxygenase 1 and 2 inhibitor). Both inhibitors were administered iv 15 min before the IL-1?. The protein levels of GLUT5 were not changed in all animal groups and those of mRNA were even increased. In summary, these findings indicate that IL-1?, at the time assayed, induced a significant reduction in the relative intrinsic activity of GLUT5 and in this decrease are involved NO signalling pathways. In this way, blockage of D-fructose intestinal uptake by IL-1? may be playing an essential role in the pathophysiology of septic shock.
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Translation driven by picornavirus IRES is hampered from Sindbis virus replicons: rescue by poliovirus 2A protease.
J. Mol. Biol.
PUBLISHED: 05-05-2010
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Alphavirus replicons are very useful for analyzing different aspects of viral molecular biology. They are also useful tools in the development of new vaccines and highly efficient expression of heterologous genes. We have investigated the translatability of Sindbis virus (SV) subgenomic mRNA bearing different 5-untranslated regions, including several viral internal ribosome entry sites (IRESs) from picornaviruses, hepatitis C virus, and cricket paralysis virus. Our findings indicate that all these IRES-containing mRNAs are initially translated in culture cells transfected with the corresponding SV replicon but their translation is inhibited in the late phase of SV replication. Notably, co-expression of different poliovirus (PV) non-structural genes reveals that the protease 2A (2A(pro)) is able to increase translation of subgenomic mRNAs containing the PV or encephalomyocarditis virus IRESs but not of those of hepatitis C virus or cricket paralysis virus. A PV 2A(pro) variant deficient in eukaryotic initiation factor (eIF) 4GI cleavage or PV protease 3C, neither of which cleaves eIF4GI, does not increase picornavirus IRES-driven translation, whereas L protease from foot-and-mouth disease virus also rescues translation. These findings suggest that the replicative foci of SV-infected cells where translation takes place are deficient in components necessary to translate IRES-containing mRNAs. In the case of picornavirus IRESs, cleavage of eIF4GI accomplished by PV 2A(pro) or foot-and-mouth disease virus protease L rescues this inhibition. eIF4GI co-localizes with ribosomes both in cells electroporated with SV replicons bearing the picornavirus IRES and in cells co-electroporated with replicons that express PV 2A(pro). These findings support the idea that eIF4GI cleavage is necessary to rescue the translation driven by picornavirus IRESs in baby hamster kidney cells that express SV replicons.
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Aerobic exercise versus combined exercise therapy in women with fibromyalgia syndrome: a randomized controlled trial.
Arch Phys Med Rehabil
PUBLISHED: 04-10-2010
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To investigate the effects of supervised aerobic exercise (AE) and a combined program of supervised aerobic, muscle strengthening, and flexibility exercises (combined exercise [CE]) on important health outcomes in women with fibromyalgia syndrome (FMS).
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Cell permeabilization by poliovirus 2B viroporin triggers bystander permeabilization in neighbouring cells through a mechanism involving gap junctions.
Cell. Microbiol.
PUBLISHED: 03-12-2010
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Poliovirus 2B protein is a well-known viroporin implicated in plasma membrane permeabilization to ions and low-molecular-weight compounds during infection. Translation in mammalian cells expressing 2B protein is inhibited by hygromycin B (HB) but remains unaffected in mock cells, which are not permeable to the inhibitor. Here we describe a previously unreported bystander effect in which healthy baby hamster kidney (BHK) cells become sensitive to HB when co-cultured with a low proportion of cells expressing poliovirus 2B. Viroporins E from mouse hepatitis virus, 6K from Sindbis virus and NS4A protein from hepatitis C virus were also able to permeabilize neighbouring cells to different extents. Expression of 2B induced permeabilization of neighbouring cell lines other than BHK. We found that gap junctions are responsible mediating the observed bystander permeabilization. Gap junctional communication was confirmed in 2B-expressing co-cultures by fluorescent dye transfer. Moreover, the presence of connexin 43 was confirmed in both mock and 2B-transfected cells. Finally, inhibition of HB entry to neighbouring cells was observed with 18alpha-glycyrrhethinic acid, an inhibitor of gap junctions. Taken together, these findings support a mechanism involving gap junctional intercellular communication in the bystander permeabilization effect observed in healthy cells co-cultured with poliovirus 2B-expressing cells.
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Schizophrenia treatment. Critical review on the drugs and mechanisms of action of antipsychotics.
Actas Esp Psiquiatr
PUBLISHED: 12-18-2009
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Schizophrenic treatment was developed during the second half of the last century, mainly within the context of the development of antipsychotic drugs. Even though there has been significant progress due to the availability and use of multiple drugs, these can still be classified into three basic groups of antipsychotic drugs (atypical antipsychotics, typical antipsychotics and dopamine partial agonist antipsychotics). Their primary antipsychotic mechanism is still the action on the dopamine systems. Many of the second-generation antipsychotics are believed to offer advantages over first-generation agents in the treatment for schizophrenia. However, the drug properties that provide the different therapeutic effects from those of the first generation are not clear and some adverse effects may still affect the patients health and quality of life. Furthermore, the efficacy of the antipsychotics is limited. This has led to the use of adjuvant medications to strengthen the treatment effects. On the other hand, work is being done on the development of new research lines to develop new non-dopaminergic antipsychotic drugs, with not very successful results. The aim of this paper is to make a brief review on the current therapeutic armamentarium for schizophrenia, the strategies to develop drugs, and theories of mechanisms of action of antipsychotics. Emphasis is placed on the new therapeutic targets for the development of future treatments.
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Post-season detraining effects on physiological and performance parameters in top-level kayakers: comparison of two recovery strategies.
J Sports Sci Med
PUBLISHED: 12-01-2009
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This study analyzed changes in physiological parameters, hormonal markers and kayaking performance following 5-wk of reduced training (RT) or complete training cessation (TC). Fourteen top-level male kayakers were randomly assigned to either a TC (n = 7) or RT group (n = 7) at the end of their competitive season (T1). Subjects undertook blood sampling and an incremental test to exhaustion on a kayak ergometer at T1 and again following 5 weeks of RT or TC (T2). Maximal oxygen uptake (VO2max) and oxygen uptake at second ventilatory threshold (VT2) significantly decreased following TC (-10.1% and -8.8%, respectively). Significant decreases were also observed in RT group but to a lesser extent (-4.8% and -5.7% respectively). Heart rate at VT2 showed significant increases following TC (3.5%). However, no changes, were detected in heart rate at VO2max in any group. Peak blood lactate remained unchanged in both groups at T2. Paddling speed at VO2max declined significantly at T2 in the TC group (-3.3%), while paddling speed at VT2 declined significantly in both groups (-5.0% and -4.2% for TC and RT, respectively). Stroke rate at VO2max and at VT2 increased significantly only following TC by 5.2% and 4.9%, respectively. Paddling power at VO2max and at VT2 decreased significantly in both groups although the values observed following RT were higher than those observed following TC. A significant decline in cortisol levels (-30%) was observed in both groups, while a higher increase in testosterone to cortisol ratio was detected in the RT group. These results indicate that a RT strategy may be more effective than complete TC in order to avoid excessive declines in cardiovascular function and kayaking performance in top-level paddlers. Key pointsShort-term (5-wk) training cessation in top-level athletes results in larger declines in physiological and performance parameters when compared to a reduced training approach.Following a competitive season in top-level athletes, both TC and RT strategies reflect an increased androgenic-anabolic activity. A higher T:C ratio was observed for the RT compared to the TC group.These results suggest the convenience of maintaining some reduced training program during transition periods in an attempt to minimize decreases in endurance performance between seasons.
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RNA nuclear export is blocked by poliovirus 2A protease and is concomitant with nucleoporin cleavage.
J. Cell. Sci.
PUBLISHED: 09-29-2009
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Cytopathic viruses have developed successful strategies to block or, at least, to attenuate host interference with their replication. Here, we have analyzed the effects of poliovirus 2A protease on RNA nuclear export. 2A protease interferes with trafficking of mRNAs, rRNAs and U snRNAs from the nucleus to the cytoplasm, without any apparent effect on tRNA transport. Traffic of newly produced mRNAs is more strongly affected than traffic of other mRNAs over-represented in the cytoplasm, such as mRNA encoding beta-actin. Inhibition of RNA nuclear export in HeLa cells expressing 2A protease is concomitant with the cleavage of Nup98, Nup153, Nup62 and their subsequent subcellular redistribution. The expression of an inactive 2A protease failed to interfere with RNA nuclear export. In addition, other related proteases, such as poliovirus 3C or foot and mouth disease virus L(pro) did not affect mRNA distribution or Nup98 integrity. Treatment of HeLa cells with interferon (IFN)-gamma increased the relative amount of Nup98. Under such conditions, the cleavage of Nup98 induced by 2A protease is partial, and thus IFN-gamma prevents the inhibition of RNA nuclear export. Taken together, these results are consistent with a specific proteolysis of Nup98 by 2A protease to prevent de novo mRNA traffic in poliovirus-infected cells.
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A peptide based on the pore-forming domain of pro-apoptotic poliovirus 2B viroporin targets mitochondria.
Biochim. Biophys. Acta
PUBLISHED: 09-14-2009
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Non-structural poliovirus 2B protein induces plasma membrane permeabilization and has been recently implicated in triggering apoptosis via the mitochondrial pathway. Here we describe that the pore-forming P3 peptide, based on the 2B amphipathic domain, translocates through the plasma membrane of culture cells and targets mitochondria. Cell permeabilization by P3 versions of different lengths, together with peptide uptake analyses supported an internalization mechanism dependent on P3 capacity to interact physically with lipid bilayers and establish permeating pores therein. Internalized P3 was found associated with mitochondria, but contrary to the parental 2B protein, the short peptide did not affect the morphology or cell distribution of these organelles, nor induced apoptosis. We conclude that P3 constitutes a mitochondriotropic sequence, which is however devoid of 2B pro-apoptotic activity.
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Simultaneous determination of methyl- and ethyl-mercury by solid-phase microextraction followed by gas chromatography atomic fluorescence detection.
J Chromatogr A
PUBLISHED: 09-03-2009
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A method for trace level determination of organomercury species in different biota matrixes by using aqueous-phase propylation followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography (GC) coupled to pyrolysis-atomic fluorescence spectrometry (Py-AFS) detection has been optimized. To maximize peak area and symmetry factors of methylmercury (MeHg) and ethylmercury (EtHg) analyzed as propyl derivatives, carrier and make-up flow rates were optimized by a user-defined experimental design. A multiple response simultaneous optimization was applied using the desirability function to achieve global optimal operating conditions. They were attained at 2 and 6 mL min(-1) as carrier and make-up gas flow rates, respectively. In addition, pyrolyser temperature was also optimized, yielding the best value at 750 degrees C. Limits of detection and quantification at the optimum conditions were 0.04 ng g(-1) and 0.13 ng g(-1) for both, MeHg and EtHg. The developed analytical procedure was validated with a certified reference material (DORM-2) and applied to the determination of organomercury incurred in waterfowl egg and fish samples.
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Translation of mRNAs from vesicular stomatitis virus and vaccinia virus is differentially blocked in cells with depletion of eIF4GI and/or eIF4GII.
J. Mol. Biol.
PUBLISHED: 07-21-2009
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Cytolytic viruses abrogate host protein synthesis to maximize the translation of their own mRNAs. In this study, we analyzed the eukaryotic initiation factor (eIF) 4G requirement for translation of vesicular stomatitis virus (VSV) and vaccinia virus (VV) mRNAs in HeLa cells using two different strategies: eIF4G depletion by small interfering RNAs or cleavage of eIF4G by expression of poliovirus 2A protease. Depletion of eIF4GI or eIF4GII moderately inhibits cellular protein synthesis, whereas silencing of both factors has only a slightly higher effect. Under these conditions, the extent of VSV protein synthesis is similar to that of nondepleted control cells, whereas VV expression is substantially reduced. Similar results were obtained when eIF4E was depleted. On the other hand, eIF4G cleavage by poliovirus 2A protease strongly inhibits translation of VV protein expression, whereas translation directed by VSV mRNAs is not abrogated, even though VSV mRNAs are capped. Therefore, the requirement for eIF4F activity is different for VV and VSV, suggesting that the molecular mechanism by which their mRNAs initiate their translation is also different. Consistent with these findings, eIF4GI does not colocalize with ribosomes in VSV-infected cells, while eIF2alpha locates at perinuclear sites coincident with ribosomes.
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Multi-biomarker responses in the freshwater mussel Dreissena polymorpha exposed to polychlorobiphenyls and metals.
Comp. Biochem. Physiol. C Toxicol. Pharmacol.
PUBLISHED: 06-16-2009
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Contaminant related changes in behavioral, phase I and II metabolizing enzymes and pro-oxidant/antioxidant processes in the freshwater mussels Dreissena polymorpha exposed to metals and PCBs were assessed. Behavioral and biochemical responses including filtering rates, key phase I, II and antioxidant enzymes and levels of metallothioneins, glutathione, lipid peroxidation and DNA strand breaks were determined in digestive glands of mussels after being exposed to sublethal levels of mercury chloride, methyl mercury, cadmium and Aroclor 1260 during 5 days. In 7 out of 12 responses analyzed, mussels showed significant differences across treatments. Unusual properties of measured ethoxyresorufin-O-deethylase (EROD) activities indicated that mussels lack an inducible CYP1A enzymatic activity. Despite of using similar exposure levels, inorganic and organic mercury showed different biomarker patterns of response with methyl mercury being more bio-available and unable to induce metallothionein proteins. Mussels exposed to Cd presented higher levels of metallothioneins and an enhanced metabolism of glutathione, whereas those exposed to Aroclor showed their antioxidant glutathione peroxidase related enzyme activities inhibited. Although there was evidence for increased lipid peroxidation under exposure to inorganic and organic mercury, only mussels exposed to Aroclor had significant greater levels than those in controls.
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HIV- 1 protease inhibits Cap- and poly(A)-dependent translation upon eIF4GI and PABP cleavage.
PLoS ONE
PUBLISHED: 06-09-2009
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A number of viral proteases are able to cleave translation initiation factors leading to the inhibition of cellular translation. This is the case of human immunodeficiency virus type 1 protease (HIV-1 PR), which hydrolyzes eIF4GI and poly(A)-binding protein (PABP). Here, the effect of HIV-1 PR on cellular and viral protein synthesis has been examined using cell-free systems. HIV-1 PR strongly hampers translation of pre-existing capped luc mRNAs, particularly when these mRNAs contain a poly(A) tail. In fact, HIV-1 PR efficiently blocks cap- and poly(A)-dependent translation initiation in HeLa extracts. Addition of exogenous PABP to HIV-1 PR treated extracts partially restores the translation of polyadenylated luc mRNAs, suggesting that PABP cleavage is directly involved in the inhibition of poly(A)-dependent translation. In contrast to these data, PABP cleavage induced by HIV-1 PR has little impact on the translation of polyadenylated encephalomyocarditis virus internal ribosome entry site (IRES)-containing mRNAs. In this case, the loss of poly(A)-dependent translation is compensated by the IRES transactivation provided by eIF4G cleavage. Finally, translation of capped and polyadenylated HIV-1 genomic mRNA takes place in HeLa extracts when eIF4GI and PABP have been cleaved by HIV-1 PR. Together these results suggest that proteolytic cleavage of eIF4GI and PABP by HIV-1 PR blocks cap- and poly(A)-dependent initiation of translation, leading to the inhibition of cellular protein synthesis. However, HIV-1 genomic mRNA can be translated under these conditions, giving rise to the production of Gag polyprotein.
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Endurance and neuromuscular changes in world-class level kayakers during a periodized training cycle.
Eur. J. Appl. Physiol.
PUBLISHED: 04-13-2009
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This study was undertaken to analyze changes in selected cardiovascular and neuromuscular variables in a group of elite kayakers across a 12-week periodized cycle of combined strength and endurance training. Eleven world-class level paddlers underwent a battery of tests and were assessed four times during the training cycle (T0, T1, T2, and T3). On each occasion subjects completed an incremental test to exhaustion on the kayak-ergometer to determine maximal oxygen uptake (VO(2max)), second ventilatory threshold (VT2), peak blood lactate, paddling speed at VO(2max) (PS(max)) and at VT2 (PS(VT2)), stroke rate at VO(2max) and at VT2, heart rate at VO(2max) and at VT2. One-repetition maximum (1RM) and mean velocity with 45% 1RM load (V (45%)) were assessed in the bench press (BP) and prone bench pull (PBP) exercises. Anthropometric measurements (skinfold thicknesses and muscle girths) were also obtained. Training volume and exercise intensity were quantified for each of three training phases (P1, P2, and P3). Significant improvements in VO(2max) (9.5%), VO(2) at VT2 (9.4%), PS(max) (6.2%), PS(VT2) (4.4%), 1RM in BP (4.2%) and PBP (5.3%), V (45%) in BP (14.4%) and PBP (10.0%) were observed from T0 to T3. A 12-week periodized strength and endurance program with special emphasis on prioritizing the sequential development of specific physical fitness components in each training phase (i.e. muscle hypertrophy and VT2 in P1, and maximal strength and aerobic power in P2) seems effective for improving both cardiovascular and neuromuscular markers of highly trained top-level athletes.
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Regulation of host translational machinery by African swine fever virus.
PLoS Pathog.
PUBLISHED: 03-31-2009
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African swine fever virus (ASFV), like other complex DNA viruses, deploys a variety of strategies to evade the hosts defence systems, such as inflammatory and immune responses and cell death. Here, we analyse the modifications in the translational machinery induced by ASFV. During ASFV infection, eIF4G and eIF4E are phosphorylated (Ser1108 and Ser209, respectively), whereas 4E-BP1 is hyperphosphorylated at early times post infection and hypophosphorylated after 18 h. Indeed, a potent increase in eIF4F assembly is observed in ASFV-infected cells, which is prevented by rapamycin treatment. Phosphorylation of eIF4E, eIF4GI and 4E-BP1 is important to enhance viral protein production, but is not essential for ASFV infection as observed in rapamycin- or CGP57380-treated cells. Nevertheless, eIF4F components are indispensable for ASFV protein synthesis and virus spread, since eIF4E or eIF4G depletion in COS-7 or Vero cells strongly prevents accumulation of viral proteins and decreases virus titre. In addition, eIF4F is not only activated but also redistributed within the viral factories at early times of infection, while eIF4G and eIF4E are surrounding these areas at late times. In fact, other components of translational machinery such as eIF2alpha, eIF3b, eIF4E, eEF2 and ribosomal P protein are enriched in areas surrounding ASFV factories. Notably, the mitochondrial network is polarized in ASFV-infected cells co-localizing with ribosomes. Thus, translation and ATP synthesis seem to be coupled and compartmentalized at the periphery of viral factories. At later times after ASFV infection, polyadenylated mRNAs disappear from the cytoplasm of Vero cells, except within the viral factories. The distribution of these pools of mRNAs is similar to the localization of viral late mRNAs. Therefore, degradation of cellular polyadenylated mRNAs and recruitment of the translation machinery to viral factories may contribute to the inhibition of host protein synthesis, facilitating ASFV protein production in infected cells.
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Dual mechanism for the translation of subgenomic mRNA from Sindbis virus in infected and uninfected cells.
PLoS ONE
PUBLISHED: 02-12-2009
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Infection of BHK cells by Sindbis virus (SV) gives rise to a profound inhibition of cellular protein synthesis, whereas translation of viral subgenomic mRNA that encodes viral structural proteins, continues for hours. To gain further knowledge on the mechanism by which this subgenomic mRNA is translated, the requirements for some initiation factors (eIFs) and for the presence of the initiator AUG were examined both in infected and in uninfected cells. To this end, BHK cells were transfected with different SV replicons or with in vitro made SV subgenomic mRNAs after inactivation of some eIFs. Specifically, eIF4G was cleaved by expression of the poliovirus 2A protease (2A(pro)) and the alpha subunit of eIF2 was inactivated by phosphorylation induced by arsenite treatment. Moreover, cellular location of these and other translation components was analyzed in BHK infected cells by confocal microscopy. Cleavage of eIF4G by poliovirus 2A(pro) does not hamper translation of subgenomic mRNA in SV infected cells, but bisection of this factor blocks subgenomic mRNA translation in uninfected cells or in cell-free systems. SV infection induces phosphorylation of eIF2alpha, a process that is increased by arsenite treatment. Under these conditions, translation of subgenomic mRNA occurs to almost the same extent as controls in the infected cells but is drastically inhibited in uninfected cells. Notably, the correct initiation site on the subgenomic mRNA is still partially recognized when the initiation codon AUG is modified to other codons only in infected cells. Finally, immunolocalization of different eIFs reveals that eIF2 alpha and eIF4G are excluded from the foci, where viral RNA replication occurs, while eIF3, eEF2 and ribosomes concentrate in these regions. These findings support the notion that canonical initiation takes place when the subgenomic mRNA is translated out of the infection context, while initiation can occur without some eIFs and even at non-AUG codons in infected cells.
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Physiological responses to mercury in feral carp populations inhabiting the low Ebro River (NE Spain), a historically contaminated site.
Aquat. Toxicol.
PUBLISHED: 02-03-2009
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The low Ebro River course (Northeast Spain) is historically affected by mercury pollution due to a chlor-alkali plant operating at the town of Flix for more than a century. River sediments analysed during the last 10 years showed high mercury levels in the river section starting just downstream the factory and spanning some 90km, down to the river delta. The possible environmental impact was studied by a combination of field and laboratory studies. Mercury concentrations in liver, kidney and muscle of feral carp (Cyprinus carpio) sampled downstream Flix were one to two orders of magnitude higher than those from carps sampled upstream Flix. Elevated levels of mercury in these samples associated with significant increases on the concentration of reduced glutathione (GSH) in liver and on mRNA expression of two metallothionein genes, MT1 and MT2, in kidney and, partially, in scales, but not in liver. Conversely, no biochemical evidence for oxidative stress or DNA damage was found in these tissues. Non-contaminated carps subjected to intraperitoneal mercury injection resulted in a 20-fold increase of MT1 and MT2 mRNA levels in carp kidney, with minimal changes in liver levels. Our data suggests the coordinate increase of metallothionein mRNA in kidney and of GSH in liver constitutes an excellent marker of exposure to sub-toxic mercury levels in carps. This study also demonstrates that apparently healthy fish populations may exceed the mercury contamination acceptable for human consumption.
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Brief cognitive-behavioral therapy with fibromyalgia patients in routine care.
Compr Psychiatry
PUBLISHED: 01-08-2009
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The purpose of the present study was to evaluate the effectiveness of a brief cognitive-behavioral therapy (CBT) group intervention for fibromyalgia syndrome in routine care.
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Translation directed by hepatitis A virus IRES in the absence of active eIF4F complex and eIF2.
PLoS ONE
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Translation directed by several picornavirus IRES elements can usually take place after cleavage of eIF4G by picornavirus proteases 2A(pro) or L(pro). The hepatitis A virus (HAV) IRES is thought to be an exception to this rule because it requires intact eIF4F complex for translation. In line with previous results we report that poliovirus (PV) 2A(pro) strongly blocks protein synthesis directed by HAV IRES. However, in contrast to previous findings we now demonstrate that eIF4G cleavage by foot-and-mouth disease virus (FMDV) L(pro) strongly stimulates HAV IRES-driven translation. Thus, this is the first observation that 2A(pro) and L(pro) exhibit opposite effects to what was previously thought to be the case in HAV IRES. This effect has been observed both in hamster BHK and human hepatoma Huh7 cells. In addition, this stimulation of translation is also observed in cell free systems after addition of purified L(pro). Notably, in presence of this FMDV protease, translation directed by HAV IRES takes place when eIF2? has been inactivated by phosphorylation. Our present findings clearly demonstrate that protein synthesis directed by HAV IRES can occur when eIF4G has been cleaved and after inactivation of eIF2. Therefore, translation directed by HAV IRES without intact eIF4G and active eIF2 is similar to that observed with other picornavirus IRESs.
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Phosphorylation of eIF2? is responsible for the failure of the picornavirus internal ribosome entry site to direct translation from Sindbis virus replicons.
J. Gen. Virol.
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Translation directed by the poliovirus (PV) or encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) is very inefficient when expressed from Sindbis virus (SV) replicons. This inhibition can be rescued by co-expression of PV 2A protease (2A(pro)). Inhibition correlates with the extensive phosphorylation of eukaryotic initiation factor (eIF) 2? induced by SV replication. Confirmation that PV or EMCV IRES-driven translation can function when eIF2? is not phosphorylated was obtained in dsRNA-activated protein kinase knockout mouse embryonic fibroblasts (PKR(-/-) MEFs), where SV replication cannot induce eIF2? phosphorylation, and in variant S51A MEFs that express an unphosphorylatable eIF2?. In these cells, PV or EMCV IRES-dependent translation operated more efficiently than in wild-type MEFs. However, this translation was potently blocked when eIF2? was phosphorylated by the addition of thapsigargin to PKR(-/-) MEFs. In addition, when wild-type eIF2? was expressed in S51A MEFs or PKR was expressed in PKR(-/-) MEFs, PV IRES-dependent translation decreased. In both cases, the decrease in PV IRES-dependent translation correlated with the phosphorylation of eIF2?. Notably, PV 2A(pro) expression rescued PV IRES-driven translation in thapsigargin-treated PKR(-/-) MEFs. Taken together, these results demonstrated that PV IRES-driven translation can take place from SV replicons if eIF2? remains unphosphorylated. Remarkably, PV IRES-dependent translation was fully functional in this system when PV 2A(pro) was present, even if eIF2? was phosphorylated.
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The renoprotective effect of L-carnitine in hypertensive rats is mediated by modulation of oxidative stress-related gene expression.
Eur J Nutr
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Arterial hypertension is associated with a high production of reactive oxygen species and a decrease in the antioxidant defense systems. Based on the lack of toxicity of L-carnitine (LC) and previous studies reporting beneficial effects of this compound in experimental models of hypertension, the aim of this work was to test the hypothesis that LC might protect the kidney against hypertension-induced oxidative damage, as well as to investigate the mechanisms involved in this effect. To this end, specific activities and protein/mRNA expression of the antioxidant enzymes (glutathione peroxidase, glutathione reductase, and superoxide dismutase), and those of NADPH oxidase (the main responsible for superoxide anion production in renal tissue) have been measured in renal cortex homogenates from NG-nitro-L-arginine methyl ester (L-NAME)-treated rats and control normotensive rats. In addition, components of the renin-angiotensin system (RAS) and redox-sensitive transcription factors (NF-?B, Nrf2, and PPAR?) have also been evaluated.
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Requirements for eIF4A and eIF2 during translation of Sindbis virus subgenomic mRNA in vertebrate and invertebrate host cells.
Cell. Microbiol.
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We have examined the requirements for the initiation factors (eIFs) eIF4A and eIF2 to translate Sindbis virus (SV) subgenomic mRNA (sgmRNA) in the natural hosts of SV: vertebrate and arthropod cells. Notably, this viral mRNA does not utilize eIF4A in SV-infected mammalian cells. However, eIF4A is required to translate this mRNA in transfected cells. Therefore, SV sgmRNA exhibits a dual mechanism for translation with respect to the use of eIF4A. Interestingly, SV genomic mRNA requires eIF4A for translation during the early phase of infection. In sharp contrast to what is observed in mammalian cells, active eIF2 is necessary to translate SV sgmRNA in mosquito cells. However, eIF4A is not necessary for SV sgmRNA translation in this cell line. In the SV sgmRNA coding region, proximal to the initiation codon is a hairpin structure that confers eIF2 independence only in mammalian cells infected by SV. Strikingly, this structure does not provide independence for eIF4A neither in mammalian nor in mosquito cells. These findings provide the first evidence of different eIF requirements for translation of SV sgmRNA in vertebrate and invertebrate cells. These observations can help to understand the interaction of SV with its host cells.
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Membrane-active peptides derived from picornavirus 2B viroporin.
Curr. Protein Pept. Sci.
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Viruses have evolved membrane-restructuring mechanisms for sustaining entry into cells, genome replication and release from host cells. Picornavirus 2B, a non-structural protein required for effective viral replication, functions as a potent intracellular pore-forming toxin by altering the permeability of cellular endomembranes. Two consecutive hydrophobic regions have been identified in 2B protein that could function as an "?-helix-turn-?-helix" hairpin membrane-anchor. A peptide derived from the first transmembrane domain comprised a "one-helix" 2B version that possesses the intrinsic pore-forming activity required to directly and effectively permeabilize the cell plasma membrane. Moreover, this miniaturized form is capable of translocating through the plasma membrane of culture cells and to target mitochondria. These evidences suggest that viroporins constitute a new source of membrane-active sequences, worth exploring as potential leads for the development of bioactive peptides, and/or as targets for the development of antiviral compounds.
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Higher risk of infection with dengue at the weekend among male Singaporeans.
Am. J. Trop. Med. Hyg.
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A growing body of evidence suggests that dengue infection in Singapore predominantly occurs away from the home, but when and where dengue transmission occurs is unclear, confounding control efforts. The authors estimate days of the week in which dengue inpatients in Singapore were infected during the period 2006-2008, based on the day they became febrile and historical data on the incubation period, using Bayesian statistical methods. Among male inpatients, the relative risk of infection is an estimated 57% higher at the weekend, suggesting infections associated with the home or leisure activities. There was no evidence of elevated risk of infection at the weekend for female inpatients. The study motivates further research identifying locales frequented in the week leading up to onset to improve the effective targeting of vector control efforts.
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