Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Genetic Surveillance Detects Both Clonal and Epidemic Transmission of Malaria following Enhanced Intervention in Senegal  [PDF]
Rachel Daniels, Hsiao-Han Chang, Papa Diogoye Séne, Danny C. Park, Daniel E. Neafsey, Stephen F. Schaffner, Elizabeth J. Hamilton, Amanda K. Lukens, Daria Van Tyne, Souleymane Mboup, Pardis C. Sabeti, Daouda Ndiaye, Dyann F. Wirth, Daniel L. Hartl, Sarah K. Volkman
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060780
Abstract: Using parasite genotyping tools, we screened patients with mild uncomplicated malaria seeking treatment at a clinic in Thiès, Senegal, from 2006 to 2011. We identified a growing frequency of infections caused by genetically identical parasite strains, coincident with increased deployment of malaria control interventions and decreased malaria deaths. Parasite genotypes in some cases persisted clonally across dry seasons. The increase in frequency of genetically identical parasite strains corresponded with decrease in the probability of multiple infections. Further, these observations support evidence of both clonal and epidemic population structures. These data provide the first evidence of a temporal correlation between the appearance of identical parasite types and increased malaria control efforts in Africa, which here included distribution of insecticide treated nets (ITNs), use of rapid diagnostic tests (RDTs) for malaria detection, and deployment of artemisinin combination therapy (ACT). Our results imply that genetic surveillance can be used to evaluate the effectiveness of disease control strategies and assist a rational global malaria eradication campaign.
Operational research to inform a sub-national surveillance intervention for malaria elimination in Solomon Islands
Jo-An Atkinson, Marie-Louise Johnson, Rushika Wijesinghe, Albino Bobogare, L Losi, Matthew O'Sullivan, Yuka Yamaguchi, Geoffrey Kenilorea, Andrew Vallely, Qin Cheng, Andrew Ebringer, Lisa Bain, Karen Gray, Ivor Harris, Maxine Whittaker, Heidi Reid, Archie Clements, Dennis Shanks
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-101
Abstract: A mixed method study was carried out in Isabel Province in late 2009 and early 2010. The quantitative component was a population-based prevalence survey of 8,554 people from 129 villages, which were selected using a spatially stratified sampling approach to achieve uniform geographical coverage of populated areas. Diagnosis was initially based on Giemsa-stained blood slides followed by molecular analysis using polymerase chain reaction (PCR). Local perceptions and practices related to management of fever and treatment-seeking that would impact a surveillance intervention were also explored using qualitative research methods.Approximately 33% (8,554/26,221) of the population of Isabel Province participated in the survey. Only one subject was found to be infected with Plasmodium falciparum (Pf) (96 parasites/μL) using Giemsa-stained blood films, giving a prevalence of 0.01%. PCR analysis detected a further 13 cases, giving an estimated malaria prevalence of 0.51%. There was a wide geographical distribution of infected subjects. None reported having travelled outside Isabel Province in the previous three months suggesting low-level indigenous malaria transmission. The qualitative findings provide warning signs that the current community vigilance approach to surveillance will not be sufficient to achieve elimination. In addition, fever severity is being used by individuals as an indicator for malaria and a trigger for timely treatment-seeking and case reporting. In light of the finding of a low prevalence of parasitaemia, the current surveillance system may not be able to detect and prevent malaria resurgence.An adaption to the malERA surveillance framework is proposed and recommendations made for a tailored provincial-level surveillance intervention, which will be essential to achieve elimination, and to maintain this status while the rest of the country catches up.Solomon Islands (SI) has had one of the highest levels of documented malaria incidence in the Asia Pacif
Testing for Efficacy in Single-Subject Trials with Intervention Analysis  [PDF]
A. Savenkov,S. Wu,D. Neal
Statistics , 2014,
Abstract: Single subject or n-of-1 research designs have been widely used to evaluate treatment interventions. Many statistical procedures such as split-middle trend lines, regression trend line, Shewart-chart trend line, binomial tests, randomization tests and Tryon C-statistics have been used to analyze single-subject data, but they fail to control Type I error due to serially-dependent time-series observations. The interrupted time series analysis maintains Type I error but assumes that the intervention effect to be a linear trend change from baseline. In this paper, we consider an improved intervention analysis model (Box and Tiao, 1975) for dynamic characteristics of an intervention effect in a short series of single-subject data. The maximum likelihood estimates are derived and a hypothesis testing procedure is proposed. The method is illustrated with a real clinical trial on constraint induced language therapy for aphasia patients.
Tumor Evasion from T Cell Surveillance
Katrin T pfer,Stefanie Kempe,Nadja Müller,Marc Schmitz,Michael Bachmann,Marc Cartellieri,Gabriele Schackert,Achim Temme
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/918471
Abstract: An intact immune system is essential to prevent the development and progression of neoplastic cells in a process termed immune surveillance. During this process the innate and the adaptive immune systems closely cooperate and especially T cells play an important role to detect and eliminate tumor cells. Due to the mechanism of central tolerance the frequency of T cells displaying appropriate arranged tumor-peptide-specific-T-cell receptors is very low and their activation by professional antigen-presenting cells, such as dendritic cells, is frequently hampered by insufficient costimulation resulting in peripheral tolerance. In addition, inhibitory immune circuits can impair an efficient antitumoral response of reactive T cells. It also has been demonstrated that large tumor burden can promote a state of immunosuppression that in turn can facilitate neoplastic progression. Moreover, tumor cells, which mostly are genetically instable, can gain rescue mechanisms which further impair immune surveillance by T cells. Herein, we summarize the data on how tumor cells evade T-cell immune surveillance with the focus on solid tumors and describe approaches to improve anticancer capacity of T cells.
Tumor-Associated Glycans and Immune Surveillance  [PDF]
Behjatolah Monzavi-Karbassi,Anastas Pashov,Thomas Kieber-Emmons
Vaccines , 2013, DOI: 10.3390/vaccines1020174
Abstract: Changes in cell surface glycosylation are a hallmark of the transition from normal to inflamed and neoplastic tissue. Tumor-associated carbohydrate antigens (TACAs) challenge our understanding of immune tolerance, while functioning as immune targets that bridge innate immune surveillance and adaptive antitumor immunity in clinical applications. T-cells, being a part of the adaptive immune response, are the most popular component of the immune system considered for targeting tumor cells. However, for TACAs, T-cells take a back seat to antibodies and natural killer cells as first-line innate defense mechanisms. Here, we briefly highlight the rationale associated with the relative importance of the immune surveillance machinery that might be applicable for developing therapeutics.
Magnetic Nanoparticles: A Subject for Both Fundamental Research and Applications  [PDF]
S. Bedanta,A. Barman,W. Kleemann,O. Petracic,T. Seki
Journal of Nanomaterials , 2013, DOI: 10.1155/2013/952540
Abstract: Single domain magnetic nanoparticles (MNPs) have been a vivid subject of intense research for the last fifty years. Preparation of magnetic nanoparticles and nanostructures has been achieved by both bottom-up and top-down approaches. Single domain MNPs show Néel-Brown-like relaxation. The Stoner-Wohlfarth model describes the angular dependence of the switching of the magnetization of a single domain particle in applied magnetic fields. By varying the spacing between the particles, the inter-particle interactions can be tuned. This leads to various supermagnetic states such as superparamagnetism, superspin glass, and superferromagnetism. Recently, the study of the magnetization dynamics of such single domain MNPs has attracted particular attention, and observations of various collective spin wave modes in patterned nanomagnet arrays have opened new avenues for on-chip microwave communications. MNPs have the potential for various other applications such as future recording media and in medicine. We will discuss the various aspects involved in the research on MNPs. 1. Introduction Modern technologies aided the invention of various new magnetic materials, synthetic structures, micro- and nanostructures, and metamaterials. Magnetism has come a long way and found applications in a range of multidisciplinary fields in present and future nanotechnologies like nonvolatile magnetic memory [1], magnetic storage media [2], magnetic recording heads [3], magnetic resonance imaging [4], and in biomedicine and health science [5]. Emerging technologies such as spin logic [6, 7], spin torque nano-oscillators (STNOs) [8], and magnonic crystals [9] have also become very active. The new technologies demand the invention of new material properties, which requires structuring of known materials in all three dimensions at various length scales and exploiting dynamical magnetic properties over various timescales. For various applications, exploration of a variety of new phenomena is required, and this ranges from slower processes such as domain wall and magnetic vortex dynamics to faster processes such as spin wave propagation and localization, ultrafast demagnetization, and relaxation. This introduces magnetic structures at various length scales such as nanodots, microdisks, magnetic nanowires, and nanostripes. Here, we shall review the experimental and numerical studies of properties of magnetic nanoparticles (MNPs) together with their leading preparation techniques. Research on MNPs has been a vivid research subject over the last few decades not only for technological
Robot-Assisted Risky Intervention, Search, Rescue and Environmental Surveillance
Maki K. Habib,Yvan Baudoin
International Journal of Advanced Robotic Systems , 2010,
Abstract: Technology has become the solution to many long-standing problems, and while current technologies may be effective, it is far from fully addressing the hug, complex, difficult and challenging tasks associated with disaster missions and risky intervention. The challenge is in finding creative, reliable and applicable technical solutions in such highly constrained and uncertain environment. In addition, it is necessary to overcome constrains on resources by developing innovative, cost effective and practical technology. Robotics can play important intelligent and technological roles that support first response equipment in harsh and dangerous environments while replacing rescue personnel from entering unreachable or unsafe places. Robotics solutions that are well adapted to local conditions of unstructured and unknown environment can greatly improve safety and security of personnel as well as work efficiency, productivity and flexibility. Solving and fulfilling the needs of such tasks presents challenges in robotic mechanical structure and mobility, sensors and sensor fusion, autonomous and semi autonomous control, planning and navigation, and machine intelligence. This paper categorizes the source of disasters and associated missions, and highlights the needs for suitable and reliable technology and technical and functional requirements of robotic systems to fulfill task objectives. In addition, it shows that robotic technologies can be used for disasters prevention or early warning, intervention and recovery efforts during disasters with all possible kinds of relevant missions while ensuring quality of service and safety of human beings. Some of these missions may include: demining, search and rescue, surveillance, reconnaissance and risk assessment, evacuation assistance, intrusion/victim detection and assessment, etc.
Conceptualising the technical relationship of animal disease surveillance to intervention and mitigation as a basis for economic analysis
Barbara H?sler, Keith S Howe, Katharina DC St?rk
BMC Health Services Research , 2011, DOI: 10.1186/1472-6963-11-225
Abstract: Economics provides criteria to guide decisions aimed at optimising the net benefits from the use of scarce resources. Assessing the benefits of disease mitigation is no exception. However, the technical complexity of mitigation means that economic evaluation is not straightforward because of the technical relationship of surveillance to intervention. We argue that analysis of the magnitudes and distribution of benefits and costs for any given strategy, and hence the outcome in net terms, requires that mitigation is considered in three conceptually distinct stages. In Stage I, 'sustainment', the mitigation objective is to sustain a free or acceptable status by preventing an increase of a pathogen or eliminating it when it occurs. The role of surveillance is to document that the pathogen remains below a defined threshold, giving early warning of an increase in incidence or other significant changes in risk, and enabling early response. If a pathogen is not contained, the situation needs to be assessed as Stage II, 'investigation'. Here, surveillance obtains critical epidemiological information to decide on the appropriate intervention strategy to reduce or eradicate a disease in Stage III, 'implementation'. Stage III surveillance informs the choice, timing, and scale of interventions and documents the progress of interventions directed at prevalence reduction in the population.This article originates from a research project to develop a conceptual framework and practical tool for the economic evaluation of surveillance. Exploring the technical relationship between mitigation as a source of economic value and surveillance and intervention as sources of economic cost is crucial. A framework linking the key technical relationships is proposed. Three conceptually distinct stages of mitigation are identified. Avian influenza, salmonella, and foot and mouth disease are presented to illustrate the framework.The broad use of animal disease surveillance (definitions of key ter
Surveillance and Control of Aedes albopictus in the Swiss-Italian Border Region: Differences in Egg Densities between Intervention and Non-intervention Areas  [PDF]
Tobias T. Suter?,Eleonora Flacio?,Bego?a Feijoó Fari?a?,Lukas Engeler?,Mauro Tonolla?,Lêda N. Regis?,Maria A. V. de Melo Santos?,Pie Müller
PLOS Neglected Tropical Diseases , 2016, DOI: 10.1371/journal.pntd.0004315
Abstract: Background Aedes albopictus, the Asian tiger mosquito, originates from the tropical and subtropical regions of Southeast Asia. Over the recent decades it has been passively spread across the globe, primarily through the used tyre trade and passive transportation along major traffic routes. A. albopictus is a proven vector for many arboviruses, most notably chikungunya and dengue, with recent outbreaks also in continental Europe. In southern Switzerland, in the Canton of Ticino A. albopictus was spotted for the first time in 2003. Since then the local authorities have implemented a control programme based on larval source reduction. Despite these efforts, mosquito densities have increased over the last decade, casting doubts on the effectiveness of such larval control programmes. Methodology/Principal Findings The Italian communities just across the Swiss-Italian border lack a control programme. This motivated us to compare the intervention and the non-intervention areas side by side in an attempt to find evidence for, or against, the effectiveness of larval A. albopictus control. Using ovitraps and a randomised sampling scheme, we examined the seasonal and spatial abundance of A. albopictus in sylvatic and urban environments across the Swiss-Italian border in 2012 and 2013. In the urban environments of the non-intervention area, egg densities were 2.26 times higher as compared to the intervention area. In the sylvatic environments, as compared to the urban environments, egg densities were 36% in the intervention area and 18% in the non-intervention area. Conclusions/Significance Though alternative explanations are also valid, the results support the hypothesis that the Ticino intervention programme does have an impact. At the same time the data also suggest that current larval interventions fall short in gaining full control over the mosquito, calling for the evaluation of additional, or alternative, approaches. Ideally, these should also consider inclusion of the neighbouring Italian communities in the surveillance and control efforts.
The role of the microenvironment in tumor immune surveillance  [cached]
Oluwadayo Oluwadara,Luca Giacomelli,Xenia Brant,Russell Christensen4
Bioinformation , 2011,
Abstract: The evidence appears compelling that the microenvironment, and associated biological cellular and molecular factors, may contribute to the progression of a variety of tumors. The effects of the microenvironment may directly influence the plasticity of T cell lineages, which was recently discussed (O’Shea & Paul, 2010 ). To review the putative role of the microenvironment in modulating the commitment of tumor immune surveillance, we use the model of oral premalignant lesions.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.