1,558 research outputs found

    Screening and evaluation of antiparasitic and in vitro anticancer activities of Panamanian endophytic fungi

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    Many compounds produced by fungi have relevant pharmaceutical applications. The purpose of this study was to collect and isolate endophytic fungi from different regions of Panama and then to test their potential therapeutic activities against Leishmania donovani, Plasmodium falciparum, and Trypanosoma cruzi as well as their anticancer activities in MCF-7 cells. Of the 25 fungal isolates obtained, ten of them had good anti-parasitic potential, showing selective activity against L. donovani; four had significant anti-malarial activity; and three inhibited the growth of T. cruzi. Anticancer activity was demonstrated in four isolates. Of the active isolates, Edenia sp. strain F0755, Xylaria sp. strain F1220, Aspergillus sp. strain F1544, Mycoleptodiscus sp. strain F0194, Phomopsis sp. strain F1566, Pycnoporus sp. strain F0305, and Diaporthe sp. strain F1647 showed the most promise based on their selective bioactivity and lack of toxicity in the assays.Many compounds produced by fungi have relevant pharmaceutical applications. The purpose of this study was to collect and isolate endophytic fungi from different regions of Panama and then to test their potential therapeutic activities against Leishmania donovani, Plasmodium falciparum, and Trypanosoma cruzi as well as their anticancer activities in MCF-7 cells. Of the 25 fungal isolates obtained, ten of them had good anti-parasitic potential, showing selective activity against L. donovani; four had significant anti-malarial activity; and three inhibited the growth of T. cruzi. Anticancer activity was demonstrated in four isolates. Of the active isolates, Edenia sp. strain F0755, Xylaria sp. strain F1220, Aspergillus sp. strain F1544, Mycoleptodiscus sp. strain F0194, Phomopsis sp. strain F1566, Pycnoporus sp. strain F0305, and Diaporthe sp. strain F1647 showed the most promise based on their selective bioactivity and lack of toxicity in the assays

    Screening and evaluation of antiparasitic and in vitro anticancer activities of Panamanian endophytic fungi

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    Parasitic infections are major causes of human chronic diseases in most countries of the tropics. The parasites include protozoa and helminths, infect billions of people, and the resulting diseases cause debilitating injuries such as blind ness and disfigurement, or death in millions of people. According to World Health Organization (WHO) estimates, 25% of the human population is infected with parasitic worms. However, attempts to develop vaccines against these pathogens have been frustrated by the difficulty of cultivating the parasites in the laboratory, the complexity of their multicellular organization and—in many species—their multistage development, in addition to their impressive antigenic variability [http://www.who.int/vaccine_research/diseases/ soa_parasitic/en/index.html]. Malaria is the most dangerous parasitic disease, as evidenced by the high rates of complications and mortality caused by the most fatal species, Plasmodium falciparum [15]. Chagas disease, or American trypanosomiasis, is a potentially life-threatening two-phase illness caused by the protozoan Trypanosoma cruzi. The acute phase persists for about two months after infection; symptoms are absent or mild and can include fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling, and abdominal or chest pain. In the chronic phase, the parasites reside mainly in the heart and digestive muscle, resulting in cardiac disorders in up to 30% of patients and digestive, neurological, or mixed pathologies in up to 10%. Eventually, the infection can lead to sudden death or heart failure, caused by progressive destruction of cardiac muscle [10,15]. Leishmaniasis, a worldwide disease, is caused by several species of the flagellated protozoan parasite Leishmania. In its more severe forms, the disease causes serious disfigurement and may be fatal. The WHO estimates a worldwide prevalence of leishmaniasis of approximately 12 million cases, with an annual mortality of about 60,000 and approximately 350 million people at risk. The expansion of leishmaniasis and the alarming rise in the number of cases has been attributed to environmental changes, such as deforestation, dam construction, new irrigation schemes, and the migration of non-immune individuals to endemic areas [10,15]. At the same time, the frequency of drug-resistant parasites has greatly increased and most treatments involve highly toxic drugs. In addition, the chemotherapeutic agents used in patients with these diseases have lacked effectiveness. Thus, there is an urgent need to search for novel drugs from previously unexplored sources, including natural products, to combat the global health problems posed by parasitic infections. Cancer is another major cause of mortality worldwide; in 2008, it accounted for 7.6 million deaths. According to WHO forecasts, an increase to 11 million deaths annually is expected by 2030. The prevalence is higher in low and middle-income countries. As a part of the on-going research activities, the Panamanian International Cooperative Biodiversity Group (ICBG) [17] recently decided to explore endophytic fungi as a source of molecules with antiparasitic and anticancer bioactivities [18,21,22]. Within the ICBG program, we have assayed the antiparasitic and in vitro anticancer activities of 25 isolates, while also analyzing the effect of the culture medium on the production of secondary metabolites by Panamanian endophytic fungi. The results of these studies are reported and discussed hereinParasitic infections are major causes of human chronic diseases in most countries of the tropics. The parasites include protozoa and helminths, infect billions of people, and the resulting diseases cause debilitating injuries such as blind ness and disfigurement, or death in millions of people. According to World Health Organization (WHO) estimates, 25% of the human population is infected with parasitic worms. However, attempts to develop vaccines against these pathogens have been frustrated by the difficulty of cultivating the parasites in the laboratory, the complexity of their multicellular organization and—in many species—their multistage development, in addition to their impressive antigenic variability [http://www.who.int/vaccine_research/diseases/ soa_parasitic/en/index.html]. Malaria is the most dangerous parasitic disease, as evidenced by the high rates of complications and mortality caused by the most fatal species, Plasmodium falciparum [15]. Chagas disease, or American trypanosomiasis, is a potentially life-threatening two-phase illness caused by the protozoan Trypanosoma cruzi. The acute phase persists for about two months after infection; symptoms are absent or mild and can include fever, headache, enlarged lymph glands, pallor, muscle pain, difficulty in breathing, swelling, and abdominal or chest pain. In the chronic phase, the parasites reside mainly in the heart and digestive muscle, resulting in cardiac disorders in up to 30% of patients and digestive, neurological, or mixed pathologies in up to 10%. Eventually, the infection can lead to sudden death or heart failure, caused by progressive destruction of cardiac muscle [10,15]. Leishmaniasis, a worldwide disease, is caused by several species of the flagellated protozoan parasite Leishmania. In its more severe forms, the disease causes serious disfigurement and may be fatal. The WHO estimates a worldwide prevalence of leishmaniasis of approximately 12 million cases, with an annual mortality of about 60,000 and approximately 350 million people at risk. The expansion of leishmaniasis and the alarming rise in the number of cases has been attributed to environmental changes, such as deforestation, dam construction, new irrigation schemes, and the migration of non-immune individuals to endemic areas [10,15]. At the same time, the frequency of drug-resistant parasites has greatly increased and most treatments involve highly toxic drugs. In addition, the chemotherapeutic agents used in patients with these diseases have lacked effectiveness. Thus, there is an urgent need to search for novel drugs from previously unexplored sources, including natural products, to combat the global health problems posed by parasitic infections. Cancer is another major cause of mortality worldwide; in 2008, it accounted for 7.6 million deaths. According to WHO forecasts, an increase to 11 million deaths annually is expected by 2030. The prevalence is higher in low and middle-income countries. As a part of the on-going research activities, the Panamanian International Cooperative Biodiversity Group (ICBG) [17] recently decided to explore endophytic fungi as a source of molecules with antiparasitic and anticancer bioactivities [18,21,22]. Within the ICBG program, we have assayed the antiparasitic and in vitro anticancer activities of 25 isolates, while also analyzing the effect of the culture medium on the production of secondary metabolites by Panamanian endophytic fungi. The results of these studies are reported and discussed herei

    Structural issues affecting mixed methods studies in health research: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Health researchers undertake studies which combine qualitative and quantitative methods. Little attention has been paid to the structural issues affecting this mixed methods approach. We explored the facilitators and barriers to undertaking mixed methods studies in health research.</p> <p>Methods</p> <p>Face-to-face semi-structured interviews with 20 researchers experienced in mixed methods research in health in the United Kingdom.</p> <p>Results</p> <p>Structural facilitators for undertaking mixed methods studies included a perception that funding bodies promoted this approach, and the multidisciplinary constituency of some university departments. Structural barriers to exploiting the potential of these studies included a lack of education and training in mixed methods research, and a lack of templates for reporting mixed methods articles in peer-reviewed journals. The 'hierarchy of evidence' relating to effectiveness studies in health care research, with the randomised controlled trial as the gold standard, appeared to pervade the health research infrastructure. Thus integration of data and findings from qualitative and quantitative components of mixed methods studies, and dissemination of integrated outputs, tended to occur through serendipity and effort, further highlighting the presence of structural constraints. Researchers are agents who may also support current structures - journal reviewers and editors, and directors of postgraduate training courses - and thus have the ability to improve the structural support for exploiting the potential of mixed methods research.</p> <p>Conclusion</p> <p>The environment for health research in the UK appears to be conducive to mixed methods research but not to exploiting the potential of this approach. Structural change, as well as change in researcher behaviour, will be necessary if researchers are to fully exploit the potential of using mixed methods research.</p

    Evaluation of the feasibility, diagnostic yield, and clinical utility of rapid genome sequencing in infantile epilepsy (Gene-STEPS): an international, multicentre, pilot cohort study

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    BACKGROUND: Most neonatal and infantile-onset epilepsies have presumed genetic aetiologies, and early genetic diagnoses have the potential to inform clinical management and improve outcomes. We therefore aimed to determine the feasibility, diagnostic yield, and clinical utility of rapid genome sequencing in this population. METHODS: We conducted an international, multicentre, cohort study (Gene-STEPS), which is a pilot study of the International Precision Child Health Partnership (IPCHiP). IPCHiP is a consortium of four paediatric centres with tertiary-level subspecialty services in Australia, Canada, the UK, and the USA. We recruited infants with new-onset epilepsy or complex febrile seizures from IPCHiP centres, who were younger than 12 months at seizure onset. We excluded infants with simple febrile seizures, acute provoked seizures, known acquired cause, or known genetic cause. Blood samples were collected from probands and available biological parents. Clinical data were collected from medical records, treating clinicians, and parents. Trio genome sequencing was done when both parents were available, and duo or singleton genome sequencing was done when one or neither parent was available. Site-specific protocols were used for DNA extraction and library preparation. Rapid genome sequencing and analysis was done at clinically accredited laboratories, and results were returned to families. We analysed summary statistics for cohort demographic and clinical characteristics and the timing, diagnostic yield, and clinical impact of rapid genome sequencing. FINDINGS: Between Sept 1, 2021, and Aug 31, 2022, we enrolled 100 infants with new-onset epilepsy, of whom 41 (41%) were girls and 59 (59%) were boys. Median age of seizure onset was 128 days (IQR 46-192). For 43 (43% [binomial distribution 95% CI 33-53]) of 100 infants, we identified genetic diagnoses, with a median time from seizure onset to rapid genome sequencing result of 37 days (IQR 25-59). Genetic diagnosis was associated with neonatal seizure onset versus infantile seizure onset (14 [74%] of 19 vs 29 [36%] of 81; p=0·0027), referral setting (12 [71%] of 17 for intensive care, 19 [44%] of 43 non-intensive care inpatient, and 12 [28%] of 40 outpatient; p=0·0178), and epilepsy syndrome (13 [87%] of 15 for self-limited epilepsies, 18 [35%] of 51 for developmental and epileptic encephalopathies, 12 [35%] of 34 for other syndromes; p=0·001). Rapid genome sequencing revealed genetic heterogeneity, with 34 unique genes or genomic regions implicated. Genetic diagnoses had immediate clinical utility, informing treatment (24 [56%] of 43), additional evaluation (28 [65%]), prognosis (37 [86%]), and recurrence risk counselling (all cases). INTERPRETATION: Our findings support the feasibility of implementation of rapid genome sequencing in the clinical care of infants with new-onset epilepsy. Longitudinal follow-up is needed to further assess the role of rapid genetic diagnosis in improving clinical, quality-of-life, and economic outcomes. FUNDING: American Academy of Pediatrics, Boston Children's Hospital Children's Rare Disease Cohorts Initiative, Canadian Institutes of Health Research, Epilepsy Canada, Feiga Bresver Academic Foundation, Great Ormond Street Hospital Charity, Medical Research Council, Murdoch Children's Research Institute, National Institute of Child Health and Human Development, National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre, One8 Foundation, Ontario Brain Institute, Robinson Family Initiative for Transformational Research, The Royal Children's Hospital Foundation, University of Toronto McLaughlin Centre

    The construction of viewpoint aspect: the imperfective revisited

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    This paper argues for a constructionist approach to viewpoint Aspect by exploring the idea that it does not exert any altering force on the situation-aspect properties of predicates. The proposal is developed by analyzing the syntax and semantics of the imperfective, which has been attributed a coercer role in the literature as a de-telicizer and de-stativizer in the progressive, and as a de-eventivizer in the so-called ability (or attitudinal) and habitual readings. This paper proposes a unified semantics for the imperfective, preserving the properties of eventualities throughout the derivation. The paper argues that the semantics of viewpoint aspect is encoded in a series of functional heads containing interval-ordering predicates and quantifiers. This richer structure allows us to account for a greater amount of phenomena, such as the perfective nature of the individual instantiations of the event within a habitual construction or the nonculminating reading of perfective accomplishments in Spanish. This paper hypothesizes that nonculminating accomplishments have an underlying structure corresponding to the perfective progressive. As a consequence, the progressive becomes disentangled from imperfectivity and is given a novel analysis. The proposed syntax is argued to have a corresponding explicit morphology in languages such as Spanish and a nondifferentiating one in languages such as English; however, the syntax-semantics underlying both of these languages is argued to be the same

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    Peer reviewe

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

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    Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe
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