844 results on '"White, Lisa J"'
Search Results
302. Artemisinin antimalarials: preserving the âmagic bulletâ
- Author
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Maude, Richard J., primary, Woodrow, Charles J., additional, and White, Lisa J., additional
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- 2009
- Full Text
- View/download PDF
303. Prospects for Malaria Eradication in Sub-Saharan Africa
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Águas, Ricardo, primary, White, Lisa J., additional, Snow, Robert W., additional, and Gomes, M. Gabriela M., additional
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- 2008
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- View/download PDF
304. Image-based characterization of foamed polymeric tissue scaffolds
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Mather, Melissa L, primary, Morgan, Stephen P, additional, White, Lisa J, additional, Tai, Hongyun, additional, Kockenberger, Walter, additional, Howdle, Steven M, additional, Shakesheff, Kevin M, additional, and Crowe, John A, additional
- Published
- 2008
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- View/download PDF
305. Seasonality of respiratory syncytial virus infection
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Waris, Matti and White, Lisa J.
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Virus diseases -- Analysis ,Respiratory tract infections -- Analysis ,Health ,Health care industry - Published
- 2006
306. Malaria community health workers in Myanmar: a cost analysis.
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Shwe Sin Kyaw, Drake, Tom, Aung Thi, Myat Phone Kyaw, Thaung Hlaing, Smithuis, Frank M., White, Lisa J., and Lubell, Yoel
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COMMUNITY health workers ,PUBLIC health personnel ,MALARIA ,COST analysis - Abstract
Background: Myanmar has the highest malaria incidence and attributed mortality in South East Asia with limited healthcare infrastructure to manage this burden. Establishing malaria Community Health Worker (CHW) programmes is one possible strategy to improve access to malaria diagnosis and treatment, particularly in remote areas. Despite considerable donor support for implementing CHW programmes in Myanmar, the cost implications are not well understood. Methods: An ingredients based micro-costing approach was used to develop a model of the annual implementation cost of malaria CHWs in Myanmar. A cost model was constructed based on activity centres comprising of training, patient malaria services, monitoring and supervision, programme management, overheads and incentives. The model takes a provider perspective. Financial data on CHWs programmes were obtained from the 2013 financial reports of the Three Millennium Development Goal fund implementing partners that have been working on malaria control and elimination in Myanmar. Sensitivity and scenario analyses were undertaken to outline parameter uncertainty and explore changes to programme cost for key assumptions. Results: The range of total annual costs for the support of one CHW was US$ 966-2486. The largest driver of CHW cost was monitoring and supervision (31-60% of annual CHW cost). Other important determinants of cost included programme management (15-28% of annual CHW cost) and patient services (6-12% of annual CHW cost). Within patient services, malaria rapid diagnostic tests are the major contributor to cost (64% of patient service costs). Conclusion: The annual cost of a malaria CHW in Myanmar varies considerably depending on the context and the design of the programme, in particular remoteness and the approach to monitoring and evaluation. The estimates provide information to policy makers and CHW programme planners in Myanmar as well as supporting economic evaluations of their cost-effectiveness. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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307. Dental pulp stem cells: function, isolation and applications in regenerative medicine.
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Tatullo, Marco, Marrelli, Massimo, Shakesheff, Kevin M., and White, Lisa J.
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- 2015
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308. Dietary amino acids affect intestinal Clostridium perfringens populations in broiler chickens
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Wilkie, Darryl C, primary, Van Kessel, Andrew G, additional, White, Lisa J, additional, Laarveld, Bernard, additional, and Drew, Murray D, additional
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- 2005
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309. Respiratory Syncytial Virus Epidemiology in a Birth Cohort from Kilifi District, Kenya: Infection during the First Year of Life
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Nokes, D. James, primary, Okiro, Emelda A., additional, Ngama, Mwanajuma, additional, White, Lisa J., additional, Ochola, Rachel, additional, Scott, Paul D., additional, Cane, Patricia A., additional, and Medley, Graham F., additional
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- 2004
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310. Gelatin-Based Materials in Ocular Tissue Engineering.
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Rose, James B., Pacelli, Settimio, Haj, Alicia J. El., Dua, Harminder S., Hopkinson, Andrew, White, Lisa J., and Rose, Felicity R. A. J.
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GELATIN ,MATERIALS ,TISSUE engineering ,CELL culture ,BIOPOLYMERS ,OPHTHALMOLOGY - Abstract
Gelatin has been used for many years in pharmaceutical formulation, cell culture and tissue engineering on account of its excellent biocompatibility, ease of processing and availability at low cost. Over the last decade gelatin has been extensively evaluated for numerous ocular applications serving as cell-sheet carriers, bio-adhesives and bio-artificial grafts. These different applications naturally have diverse physical, chemical and biological requirements and this has prompted research into the modification of gelatin and its derivatives. The crosslinking of gelatin alone or in combination with natural or synthetic biopolymers has produced a variety of scaffolds that could be suitable for ocular applications. This review focuses on methods to crosslink gelatin-based materials and how the resulting materials have been applied in ocular tissue engineering. Critical discussion of recent innovations in tissue engineering and regenerative medicine will highlight future opportunities for gelatin-based materials in ophthalmology. [ABSTRACT FROM AUTHOR]
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- 2014
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311. Percolation across households in mechanistic models of non-pharmaceutical interventions in SARS-CoV-2 disease dynamics.
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Franco, Caroline, Ferreira, Leonardo Souto, Sudbrack, Vítor, Borges, Marcelo Eduardo, Poloni, Silas, Prado, Paulo Inácio, White, Lisa J., Águas, Ricardo, Kraenkel, Roberto André, and Coutinho, Renato Mendes
- Abstract
Since the emergence of the novel coronavirus disease 2019 (COVID-19), mathematical modelling has become an important tool for planning strategies to combat the pandemic by supporting decision-making and public policies, as well as allowing an assessment of the effect of different intervention scenarios. A proliferation of compartmental models were developed by the mathematical modelling community in order to understand and make predictions about the spread of COVID-19. While compartmental models are suitable for simulating large populations, the underlying assumption of a well-mixed population might be problematic when considering non-pharmaceutical interventions (NPIs) which have a major impact on the connectivity between individuals in a population. Here we propose a modification to an extended age-structured SEIR (susceptible–exposed–infected–recovered) framework, with dynamic transmission modelled using contact matrices for various settings in Brazil. By assuming that the mitigation strategies for COVID-19 affect the connections among different households, network percolation theory predicts that the connectivity among all households decreases drastically above a certain threshold of removed connections. We incorporated this emergent effect at population level by modulating home contact matrices through a percolation correction function, with the few additional parameters fitted to hospitalisation and mortality data from the city of São Paulo. Our model with percolation effects was better supported by the data than the same model without such effects. By allowing a more reliable assessment of the impact of NPIs, our improved model provides a better description of the epidemiological dynamics and, consequently, better policy recommendations. • Bridging the gap between compartmental and household-level models for COVID-19. • Mean-field approach to modelling household contact patterns (percolation effect). • Useful for modelling interventions targeted at household-level. • Better agreement to data was observed when implementing the percolation effect. • General approach that can be applied to other dynamic infectious disease models. [ABSTRACT FROM AUTHOR]
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- 2022
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312. Impact of malaria during pregnancy on pregnancy outcomes in a Ugandan prospective cohort with intensive malaria screening and prompt treatment.
- Author
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De Beaudrap, Pierre, Turyakira, Eleanor, White, Lisa J., Nabasumba, Carolyn, Tumwebaze, Benon, Muehlenbachs, Atis, Guérin, Philippe J., Boum II, Yap, McGready, Rose, and Piola, Patrice
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MALARIA in pregnancy ,EPIDEMIOLOGY ,MALARIA treatment ,PLACENTA ,PARASITEMIA ,MISCARRIAGE - Abstract
Background: Malaria in pregnancy (MiP) is a major public health problem in endemic areas of sub-Saharan Africa and has important consequences on birth outcome. Because MiP is a complex phenomenon and malaria epidemiology is rapidly changing, additional evidence is still required to understand how best to control malaria. This study followed a prospective cohort of pregnant women who had access to intensive malaria screening and prompt treatment to identify factors associated with increased risk of MiP and to analyse how various characteristics of MiP affect delivery outcomes. Methods: Between October 2006 and May 2009, 1,218 pregnant women were enrolled in a prospective cohort. After an initial assessment, they were screened weekly for malaria. At delivery, blood smears were obtained from the mother, placenta, cord and newborn. Multivariate analyses were performed to analyse the association between mothers' characteristics and malaria risk, as well as between MiP and birth outcome, length and weight at birth. This study is a secondary analysis of a trial registered with ClinicalTrials.gov, number NCT00495508. Results: Overall, 288/1,069 (27%) mothers had 345 peripheral malaria infections. The risk of peripheral malaria was higher in mothers who were younger, infected with HIV, had less education, lived in rural areas or reported no bed net use, whereas the risk of placental infection was associated with more frequent malaria infections and with infection during late pregnancy. The risk of pre-term delivery and of miscarriage was increased in mothers infected with HIV, living in rural areas and with MiP occurring within two weeks of delivery. In adjusted analysis, birth weight but not length was reduced in babies of mothers exposed to MiP (-60g, 95%CI: -120 to 0 for at least one infection and -150 g, 95%CI: -280 to -20 for >1 infections). Conclusions: In this study, the timing, parasitaemia level and number of peripherally-detected malaria infections, but not the presence of fever, were associated with adverse birth outcomes. Hence, prompt malaria detection and treatment should be offered to pregnant women regardless of symptoms or other preventive measures used during pregnancy, and with increased focus on mothers living in remote areas. [ABSTRACT FROM AUTHOR]
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- 2013
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313. Defining Falciparum-Malaria-Attributable Severe Febrile Illness in Moderate-to-High Transmission Settings on the Basis of Plasma PfHRP2 Concentration.
- Author
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Hendriksen, Ilse C. E., White, Lisa J., Veenemans, Jacobien, Mtove, George, Woodrow, Charles, Amos, Ben, Saiwaew, Somporn, Gesase, Samwel, Nadjm, Behzad, Silamut, Kamolrat, Joseph, Sarah, Chotivanich, Kesinee, Day, Nicholas P. J., von Seidlein, Lorenz, Verhoef, Hans, Reyburn, Hugh, White, Nicholas J., and Dondorp, Arjen M.
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MALARIA diagnosis , *PARASITEMIA , *HISTIDINE , *PLASMODIUM falciparum , *BLOOD plasma , *INFECTIOUS disease transmission , *MEDICAL statistics - Abstract
Background. In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations.Methods. Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6−60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease.Results. The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%–100%), with a sensitivity of 74% (95% CI, 72%–77%), whereas a concentration of <200 ng/mL denoted severe febrile illness of an alternative diagnosis in >10% (95% CI, 3%–27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles.Conclusions. The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting. [ABSTRACT FROM AUTHOR]
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- 2013
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314. The effect of processing variables on morphological and mechanical properties of supercritical CO2 foamed scaffolds for tissue engineering.
- Author
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White, Lisa J., Hutter, Victoria, Tai, Hongyun, Howdle, Steven M., and Shakesheff, Kevin M.
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SUPERCRITICAL carbon dioxide ,TISSUE engineering ,BONE regeneration ,BONE mechanics ,MOLECULAR weights ,LACTIC acid ,TISSUE scaffolds ,POROSITY - Abstract
Abstract: The porous structure of a scaffold determines the ability of bone to regenerate within this environment. In situations where the scaffold is required to provide mechanical function, balance must be achieved between optimizing porosity and maximizing mechanical strength. Supercritical CO
2 foaming can produce open-cell, interconnected structures in a low-temperature, solvent-free process. In this work, we report on foams of varying structural and mechanical properties fabricated from different molecular weights of poly(dl-lactic acid) Pdl LA (57, 25 and 15kDa) and by varying the depressurization rate. Rapid depressurization rates produced scaffolds with homogeneous pore distributions and some closed pores. Decreasing the depressurization rate produced scaffolds with wider pore size distributions and larger, more interconnected pores. In compressive testing, scaffolds produced from 57kDa Pdl LA exhibited typical stress–strain curves for elastomeric open-cell foams whereas scaffolds fabricated from 25 and 15kDa Pdl LA behaved as brittle foams. The structural and mechanical properties of scaffolds produced from 57kDa Pdl LA by scCO2 ensure that these scaffolds are suitable for potential applications in bone tissue engineering. [Copyright &y& Elsevier]- Published
- 2012
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315. Intrahost modeling of artemisinin resistance in Plasmodium falciparum.
- Author
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SaraIamb, Sompob, Pan-Ngum, Wirichada, Maude, Richard J., Lee, Sue J., Tarning, Joel, Lindegárdh, Niklas, Chotivanich, Kesinee, Nosten, François, Day, Nicholas P. J., Socheat, Duong, White, Nicholas J., Dondorp, Arjen M., and White, Lisa J.
- Subjects
ARTEMISININ ,PLASMODIUM falciparum ,PARASITES ,MALARIA - Abstract
Artemisinin-resistant Plasmodium falciparum malaria has emerged in western Cambodia. Resistance is characterized by prolonged in vivo parasite clearance times (PCTs) following artesunate treatment. The biological basis is unclear. The hypothesis that delayed parasite clearance results from a stage-specific reduction in artemisinin sensitivity of the circulating young asexual parasite ring stages was examined. A mathematical model was developed, describing the intrahost parasite stage-specific pharmacokinetic-pharmacodynamic relationships. Model parameters were estimated using detailed pharmacokinetic and parasite clearance data from 39 patients with uncomplicated falciparum malaria treated with artesunate from Pailin (western Cambodia) where artemisinin resistance was evident and 40 patients from Wang Pha (northwestern Thailand) where efficacy was preserved. The mathematical model reproduced the observed parasite clearance for each patient with an accurate goodnessof fit (rmsd: 0.03-0.67 in log
10 scale). The parameter sets that provided the best fits with the observed in vivo data consist of a highly conserved concentration-effect relationship for the trophozoite and schizont parasite stages, but a variable relationship for the ring stages. The model-derived assessment suggests that the efficacy of artesunate on ring stage parasites is reduced significantly in Pailin. This result supports the hypothesis that artemisinin resistance mainly reflects reduced ring-stage susceptibility and predicts that doubling the frequency of dosing will accelerate clearance of artemisinin-resistant parasites. [ABSTRACT FROM AUTHOR]- Published
- 2011
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316. Artemisinin antimalarials: preserving the 'magic bullet'.
- Author
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Maude, Richard J., Woodrow, Charles J., and White, Lisa J.
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- 2010
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317. Probability of emergence of antimalarial resistance in different stages of the parasite life cycle.
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Pongtavornpinyo, Wirichada, Hastings, Ian M., Dondorp, Arjen, White, Lisa J., Maude, Richard J., Saralamba, Sompob, Day, Nicholas P., White, Nicholas J., and Boni, Maciej F.
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DRUG resistance in microorganisms ,MALARIA ,PROTOZOAN diseases ,DRUG resistance ,PHARMACOLOGY - Abstract
Understanding the evolution of drug resistance in malaria is a central area of study at the intersection of evolution and medicine. Antimalarial drug resistance is a major threat to malaria control and directly related to trends in malaria attributable mortality. Artemisinin combination therapies (ACT) are now recommended worldwide as first line treatment for uncomplicated malaria, and losing them to resistance would be a disaster for malaria control. Understanding the emergence and spread of antimalarial drug resistance in the context of different scenarios of antimalarial drug use is essential for the development of strategies protecting ACTs. In this study, we review the basic mechanisms of resistance emergence and describe several simple equations that can be used to estimate the probabilities of de novo resistance mutations at three stages of the parasite life cycle: sporozoite, hepatic merozoite and asexual blood stages; we discuss the factors that affect parasite survival in a single host in the context of different levels of antimalarial drug use, immunity and parasitaemia. We show that in the absence of drug effects, and despite very different parasite numbers, the probability of resistance emerging at each stage is very low and similar in all stages (for example per-infection probability of 10
−10 –10−9 if the per-parasite chance of mutation is 10−10 per asexual division). However, under the selective pressure provided by antimalarial treatment and particularly in the presence of hyperparasitaemia, the probability of resistance emerging in the blood stage of the parasite can be approximately five orders of magnitude higher than in the absence of drugs. Detailed models built upon these basic methods should allow us to assess the relative probabilities of resistance emergence in the different phases of the parasite life cycle. [ABSTRACT FROM AUTHOR]- Published
- 2009
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318. Respiratory Syncytial Virus Infection and Disease in Infants and Young Children Observed from Birth in Kilifi District, Kenya.
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Nokes, D. James, Okiro, Emelda A., Ngama, Mwanajuma, Ochola, Rachel, White, Lisa J., Scott, Paul D., English, Michael, Cane, Patricia A., and Medley, Graham F.
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RESPIRATORY syncytial virus ,INFANTS ,CHILDREN ,PARAMYXOVIRUSES - Abstract
Background. In developing countries, there are few data that characterize the disease burden attributable to respiratory syncytial virus (RSV) and clearly define which age group to target for vaccine intervention. Methods. Six hundred thirty-five children, recruited during the period 2002-2003, were intensively monitored until each experienced 3 epidemics of RSV infection. RSV infection was diagnosed using immunofluorescence of nasal washing specimens collected at each episode of acute respiratory infection. Incidence estimates were adjusted for seasonality of RSV exposure. Results. For 1187 child-years of observation (CYO), a total of 409 (365 primary and 82 repeat) episodes of RSV infection were identified. Adjusted incidence estimates of lower respiratory tract infection (LRTI), severe LRTI, and hospital admission were 90 cases per 1000 CYO, 43 cases per 1000 CYO, and 10 cases per 1000 CYO, respectively, and corresponding estimates among infants were 104 cases per 1000 CYO, 66 cases per 1000 CYO, and 13 cases per 1000 CYO, respectively. The proportion of cases of all-cause LRTI, and severe LRTI and hospitalizations attributable to RSV in the cohort was 13%, 19%, and 5%, respectively. Fifty-five percent to 65% of RSV-associated LRTI and severe LRTI occurred in children aged >6 months. The risk of RSV disease following primary symptomatic infection remained significant beyond the first year of life, and one-quarter of all reinfections were associated with LRTI. Conclusions. RSV accounts for a substantial proportion of the total respiratory disease in this rural population; we estimate that 85,000 cases of severe LRTI per year occur in infants in Kenya. The majority of this morbidity occurs during late infancy and early childhood-ages at which the risk of disease following infection remains significant. Disease resulting from reinfection is common. Our results inform the debate on the target age group and effectiveness of a vaccine. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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319. Estimation of gestational age from fundal height: a solution for resource-poor settings
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White, Lisa J., Lee, Sue J., Stepniewska, Kasia, Simpson, Julie A., Dwell, Saw Lu Mu, Arunjerdja, Ratree, Singhasivanon, Pratap, White, Nicholas J., Nosten, Francois, and McGready, Rose
- Abstract
Many women in resource-poor settings lack access to reliable gestational age assessment because they do not know their last menstrual period; there is no ultrasound (US) and methods of newborn gestational age dating are not practised by birth attendants. A bespoke multiple-measures model was developed to predict the expected date of delivery determined by US. The results are compared with both a linear and a nonlinear model. Prospectively collected early US and serial symphysis-pubis fundal height (SFH) data were used in the models. The data were collected from Karen and Burmese women attending antenatal care on the Thai–Burmese border. The multiple-measures model performed best, resulting in a range of accuracy depending on the number of SFH measures recorded per mother (for example six SFH measurements resulted in a prediction accuracy of ±2 weeks). SFH remains the proxy for gestational age in much of the resource-poor world. While more accurate measures should be encouraged, we demonstrate that a formula that incorporates at least three SFH measures from an individual mother and the slopes between them provide a significant increase in the accuracy of prediction compared with the linear and nonlinear formulae also using multiple SFH measures.
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- 2012
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320. A solution NMR methodology enabling the elucidation of small molecule phospholipid membrane adhesion and passive permeation parameters.
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Serrano-Sanchez, Angela, Rice, Matthew, Cassar, Joseph, White, Lisa J., Popoola, Precious I. A., Thompson, Gary S., Hiscock, Jennifer R., and Ortega-Roldan, Jose L.
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BIOLOGICAL membranes , *SMALL molecules , *NUCLEAR magnetic resonance spectroscopy , *DRUGS - Abstract
Quantifying small molecule uptake across a biological membrane of a target cell is crucial for the development of efficacious and selective drugs. However, current methods to obtaining such data are not trivial. Herein, we present an accessible, higher-throughput (20 minutes), 1H NMR spectroscopy assay, which enables the quantification of small molecule phospholipid passive membrane permeation and membrane adhesion parameters. [ABSTRACT FROM AUTHOR]
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- 2024
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321. Erratum to “The reinfection threshold”: [J. Theor. Biol. 236 (2005) 111–113]
- Author
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Gomes, M. Gabriela M., White, Lisa J., and Medley, Graham F.
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- 2006
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322. Stem cells from the dental apical papilla in extracellular matrix hydrogels mitigate inflammation of microglial cells.
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Tatic, Natalija, Rose, Felicity R. A. J., des Rieux, Anne, and White, Lisa J.
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SPINAL cord injuries ,STEM cells ,EXTRACELLULAR matrix ,HYDROGELS in medicine ,MESENCHYMAL stem cells - Abstract
After spinal cord injury (SCI) chronic inflammation hampers regeneration. Influencing the local microenvironment after SCI may provide a strategy to modulate inflammation and the immune response. The objectives of this work were to determine whether bone or spinal cord derived ECM hydrogels can deliver human mesenchymal stem cells from the apical papilla (SCAP) to reduce local inflammation and provide a regenerative microenvironment. Bone hydrogels (8 and 10 mg/ml, B8 and B10) and spinal cord hydrogels (8 mg/ml, S8) supplemented with fibrin possessed a gelation rate and a storage modulus compatible with spinal cord implantation. S8 and B8 impact on the expression of anti and pro-inflammatory cytokines (Arg1, Nos2, Tnf) in LPS treated microglial cells were assessed using solubilised and solid hydrogel forms. S8 significantly reduced the Nos2/Arg1 ratio and solubilised B8 significantly reduced Tnf and increased Arg1 whereas solid S8 and B8 did not impact inflammation in microglial cells. SCAP incorporation within ECM hydrogels did not impact upon SCAP immunoregulatory properties, with significant downregulation of Nos2/Arg1 ratio observed for all SCAP embedded hydrogels. Tnf expression was reduced with SCAP embedded in B8, reflecting the gene expression observed with the innate hydrogel. Thus, ECM hydrogels are suitable vehicles to deliver SCAP due to their physical properties, preservation of SCAP viability and immunomodulatory capacity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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323. Human population movement and behavioural patterns in malaria hotspots on the Thai–Myanmar border: implications for malaria elimination.
- Author
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Saita, Sayambhu, Pan-ngum, Wirichada, Phuanukoonnon, Suparat, Sriwichai, Patchara, Silawan, Tassanee, White, Lisa J., and Parker, Daniel M.
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POPULATION ,MALARIA ,HUMAN mechanics - Abstract
Background: Malaria is heterogeneously distributed across landscapes. Human population movement (HPM) could link sub-regions with varying levels of transmission, leading to the persistence of disease even in very low transmission settings. Malaria along the Thai–Myanmar border has been decreasing, but remains heterogeneous. This study aimed to measure HPM, associated predictors of travel, and HPM correlates of self-reported malaria among people living within malaria hotspots. Methods: 526 individuals from 279 households in two malaria hotspot areas were included in a prospective observational study. A baseline cross-sectional study was conducted at the beginning, recording both individual- and household-level characteristics. Individual movement and travel patterns were repeatedly observed over one dry season month (March) and one wet season month (May). Descriptive statistics, random effects logistic regressions, and logistic regressions were used to describe and determine associations between HPM patterns, individual-, household-factors, and self-reported malaria. Results: Trips were more common in the dry season. Malaria risk was related to the number of days doing outdoor activities in the dry season, especially trips to Myanmar, to forest areas, and overnight trips. Trips to visit forest areas were more common among participants aged 20–39, males, individuals with low income, low education, and especially among individuals with forest-related occupations. Overnight trips were more common among males, and individual with forest-related occupations. Forty-five participants reported having confirmed malaria infection within the last year. The main place of malaria blood examination and treatment was malaria post and malaria clinic, with participants usually waiting for 2–3 days from onset fever to seeking diagnosis. Individuals using bed nets, living in houses with elevated floors, and houses that received indoor residual spraying in the last year were less likely to report malaria infection. Conclusion: An understanding of HPM and concurrent malaria dynamics is important for consideration of targeted public health interventions. Furthermore, diagnosis and treatment centres must be capable of quickly diagnosing and treating infections regardless of HPM. Coverage of diagnosis and treatment centres should be broad, maintained in areas bordering malaria hotspots, and available to all febrile individuals. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
324. Additional file 1 of The assembly effect: the connectedness between populations is a double‐edged sword for public health interventions
- Author
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Tun, Sai Thein Than, Parker, Daniel M., Aguas, Ricardo, and White, Lisa J.
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3. Good health - Abstract
Additional file 1. The model structure, the model validation, and the parameter values.
325. Role of mass drug administration in elimination of Plasmodium falciparum malaria: a consensus modelling study
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Brady, Oliver J., Slater, Hannah C., Pemberton-Ross, Peter James, Wenger, Edward, Maude, Richard J., Ghani, Azra C., Penny, Melissa A., Gerardin, Jaline, White, Lisa J., Chitnis, Nakul, Aguas, Ricardo, Hay, Simon I., Smith, David L., Stuckey, Erin M., Okiro, Emelda A, Smith, Thomas A., and Okell, Lucy C.
- Subjects
3. Good health
326. Additional file 1 of The assembly effect: the connectedness between populations is a double‐edged sword for public health interventions
- Author
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Tun, Sai Thein Than, Parker, Daniel M., Aguas, Ricardo, and White, Lisa J.
- Subjects
3. Good health - Abstract
Additional file 1. The model structure, the model validation, and the parameter values.
327. Additional file 1 of Estimating the programmatic cost of targeted mass drug administration for malaria in Myanmar
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Kyaw, Shwe Sin, Delmas, Gilles, Drake, Tom L., Celhay, Olivier, Wirichada Pan-Ngum, Sasithon Pukrittayakamee, Lubell, Yoel, Aguas, Ricardo J., Maude, Richard James, White, Lisa J., and Francois Nosten
- Subjects
parasitic diseases ,Data_FILES ,health care economics and organizations ,3. Good health - Abstract
Additional file 1. The interactive costing tool. This file contains the features of malaria mass intervention costing tool.
328. Cooperative cation co-transport by supramolecular self-associating amphiphiles
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Yang, K, Boles, Jessica E., White, Lisa J., Hilton, Kira L.F., Lai, H Y, Long, Y, Hiscock, Jennifer R., and Haynes, Cally J. E.
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QD431 ,QD
329. Predicting the cost of malaria elimination in the Asia-Pacific
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Shretta, Rima, Silal, Sheetal, White, Lisa J., and Maude, Richard J.
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1. No poverty ,3. Good health
330. Extracellular matrix-derived hydrogels for dental stem cell delivery
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Viswanath, Aiswarya, Vanacker, Julie, Germain, Loïc, Leprince, Julian G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., des Rieux, Anne, Viswanath, Aiswarya, Vanacker, Julie, Germain, Loïc, Leprince, Julian G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., and des Rieux, Anne
- Abstract
Decellularized mammalian extracellular matrices (ECM) have been widely accepted as an ideal substrate for repair and remodelling of numerous tissues in clinical and pre-clinical studies. Recent studies have demonstrated the ability of ECM scaffolds derived from site-specific homologous tissues to direct cell differentiation. The present study investigated the suitability of hydrogels derived from different source tissues: bone, spinal cord and dentine, as suitable carriers to deliver human apical papilla derived mesenchymal stem cells (SCAP) for spinal cord regeneration. Bone, spinal cord, and dentine ECM hydrogels exhibited distinct structural, mechanical, and biological characteristics. All three hydrogels supported SCAP viability and proliferation. However, only spinal cord and bone derived hydrogels promoted the expression of neural lineage markers. The specific environment of ECM scaffolds significantly affected the differentiation of SCAP to a neural lineage, with stronger responses observed with spinal cord ECM hydrogels, suggesting that site-specific tissues are more likely to facilitate optimal stem cell behavior for constructive spinal cord regeneration.
331. Surface modification of P dl LGA microspheres with gelatine methacrylate: Evaluation of adsorption, entrapment, and oxygen plasma treatment approaches
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Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, Shakesheff, Kevin M., Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, and Shakesheff, Kevin M.
- Abstract
Injectable poly (dl-lactic-co-glycolic acid) (PdlLGA) microspheres are promising candidates as biodegradable controlled release carriers for drug and cell delivery applications; however, they have limited functional groups on the surface to enable dense grafting of tissue specific biocompatible molecules. In this study we have evaluated surface adsorption, entrapment and oxygen plasma treatment as three approaches to modify the surfaces of PdlLGA microspheres with gelatine methacrylate (gel-MA) as a biocompatible and photo cross-linkable macromolecule. Time of flight secondary ion mass spectroscopy (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) were used to detect and quantify gel-MA on the surfaces. Fluorescent and scanning electron microscopies (SEM) were used to image the topographical changes. Human mesenchymal stem cells (hMSCs) of immortalised cell line were cultured on the surface of gel-MA modified PdlLGA microspheres and Presto-Blue assay was used to study the effect of different surface modifications on cell proliferation. Data analysis showed that the oxygen plasma treatment approach resulted in the highest density of gel-MA deposition. This study supports oxygen plasma treatment as a facile approach to modify the surface of injectable PdlLGA microspheres with macromolecules such as gel-MA to enhance proliferation rate of injected cells and potentially enable further grafting of tissue specific molecules.
332. Translational considerations in injectable cell-based therapeutics for neurological applications: concepts, progress and challenges
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Amer, Mahetab H., Rose, Felicity R. A. J., Shakesheff, Kevin M., Modo, Michel, White, Lisa J., Amer, Mahetab H., Rose, Felicity R. A. J., Shakesheff, Kevin M., Modo, Michel, and White, Lisa J.
- Abstract
Significant progress has been made during the past decade towards the clinical adoption of cell-based therapeutics. However, existing cell-delivery approaches have shown limited success, with numerous studies showing fewer than 5% of injected cells persisting at the site of injection within days of transplantation. Although consideration is being increasingly given to clinical trial design, little emphasis has been given to tools and protocols used to administer cells. The different behaviours of various cell types, dosing accuracy, precise delivery, and cell retention and viability post-injection are some of the obstacles facing clinical translation. For efficient injectable cell transplantation, accurate characterisation of cellular health post-injection and the development of standardised administration protocols are required. This review provides an overview of the challenges facing effective delivery of cell therapies, examines key studies that have been carried out to investigate injectable cell delivery, and outlines opportunities for translating these findings into more effective cell-therapy interventions.
333. Translation of remote control regenerative technologies for bone repair
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Markides, Hareklea, McLaren, Jane S., Telling, Neil D., Alom, Noura, Al-Mutheffer, E’atelaf A., Oreffo, Richard, Zannettino, Andrew, Scammell, Brigitte E., White, Lisa J., El-Haj, Alicia, Markides, Hareklea, McLaren, Jane S., Telling, Neil D., Alom, Noura, Al-Mutheffer, E’atelaf A., Oreffo, Richard, Zannettino, Andrew, Scammell, Brigitte E., White, Lisa J., and El-Haj, Alicia
- Abstract
The role of biomechanical stimuli, or mechanotransduction, in normal bone homeostasis and repair is understood to facilitate effective osteogenesis of mesenchymal stem cells (MSCs) in vitro. Mechanotransduction has been integrated into a multitude of in vitro bone tissue engineering strategies and provides an effective means of controlling cell behaviour towards therapeutic outcomes. However, the delivery of mechanical stimuli to exogenous MSC populations, post implantation, poses a significant translational hurdle. Here, we describe an innovative bio-magnetic strategy, MICA, where magnetic nanoparticles (MNPs) are used to remotely deliver mechanical stimuli to the mechano-receptor, TREK-1, resulting in activation and downstream signalling via an external magnetic array. In these studies, we have translated MICA to a pre-clinical ovine model of bone injury to evaluate functional bone repair. We describe the development of a magnetic array capable of in vivo MNP manipulation and subsequent osteogenesis at equivalent field strengths in vitro. We further demonstrate that the viability of MICA-activated MSCs in vivo is unaffected 48 hrs post implantation. We present evidence to support early accelerated repair and preliminary enhanced bone growth in MICA-activated defects within individuals compared to internal controls. The variability in donor responses to MICA-activation was evaluated in vitro revealing that donors with poor osteogenic potential were most improved by MICA-activation. Our results demonstrate a clear relationship between responders to MICA in vitro and in vivo. These unique experiments offer exciting clinical applications for cell-based therapies as a practical in vivo source of dynamic loading, in real-time, in the absence of pharmacological agents.
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334. A biomaterials approach to influence stem cell fate in injectable cell-based therapies
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Amer, Mahetab H., Rose, Felicity R.A.J., Shakesheff, Kevin M., White, Lisa J., Amer, Mahetab H., Rose, Felicity R.A.J., Shakesheff, Kevin M., and White, Lisa J.
- Abstract
Background: Numerous stem cell therapies use injection-based administration to deliver high density cell preparations. However, cell retention rates as low as 1% have been observed within days of transplantation. This study investigated the effects of varying administration and formulation parameters of injection-based administration on cell dose recovery and differentiation fate choice of human mesenchymal stem cells. Methods: The impact of ejection rate via clinically-relevant Hamilton micro-syringes and biomaterial-assisted delivery was investigated. Cell viability, the percentage of cell dose delivered as viable cells, proliferation capacity as well as differentiation behaviour in bipotential media were assessed. Characterisation of the biomaterial-based cell carriers was also carried out. Results: A significant improvement of in vitro dose recovery in cells co-ejected with natural biomaterials was observed, with ejections within 2% (w/v) gelatin resulting in 87.5±14% of the cell dose being delivered as viable cells, compared to 32.2±19% of the dose ejected in the commonly-used saline vehicle at 10 µL/min. Improvement in cell recovery was not associated with rheological properties of biomaterials utilised, as suggested by previous studies. The extent of osteogenic differentiation was shown to be substantially altered by choice of ejection rate and cell carrier, despite limited contact time with cells during ejection. Collagen type I and bone-derived extracellular matrix cell carriers yielded significant increases in mineralised matrix deposited at day 21 relative to PBS. Conclusions: An enhanced understanding of how administration protocols and biomaterials influence cell recovery, differentiation capacity and choice of fate will facilitate the development of improved administration and formulation approaches to achieve higher efficacy in stem cell transplantation.
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335. Extracellular matrix-derived hydrogels for dental stem cell delivery
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Viswanath, Aiswarya, Vanacker, Julie, Germain, Loic, Leprince, Julien G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., des Rieux, Anne, Viswanath, Aiswarya, Vanacker, Julie, Germain, Loic, Leprince, Julien G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., and des Rieux, Anne
- Abstract
Decellularised mammalian extracellular matrices (ECM) have been widely accepted as an ideal substrate for repair and remodelling of numerous tissues in clinical and pre-clinical studies. Recent studies have demonstrated the ability of ECM scaffolds derived from site-specific homologous tissues to direct cell differentiation. The present study investigated the suitability of hydrogels derived from different source tissues: bone, spinal cord and dentine, as suitable carriers to deliver human apical papilla derived mesenchymal stem cells (SCAP) for spinal cord regeneration. Bone, spinal cord and dentine ECM hydrogels exhibited distinct structural, mechanical and biological characteristics. All three hydrogels supported SCAP viability and proliferation. However, only spinal cord and bone derived hydrogels promoted the expression of neural lineage markers. The specific environment of ECM scaffolds significantly affected the differentiation of SCAP to a neural lineage, with stronger responses observed with spinal cord ECM hydrogels, suggesting that site-specific tissues are more likely to facilitate optimal stem cell behaviour for constructive spinal cord regeneration
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336. Extracellular matrix hydrogels from decellularized tissues: structure and function
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Saldin, Lindsey T., Cramer, Madeline C, Velankar, Sachin S, White, Lisa J., Badylak, Stephen F., Saldin, Lindsey T., Cramer, Madeline C, Velankar, Sachin S, White, Lisa J., and Badylak, Stephen F.
- Abstract
Extracellular matrix (ECM) bioscaffolds prepared from decellularized tissues have been used to facilitate constructive and functional tissue remodeling in a variety of clinical applications. The discovery that these ECM materials could be solubilized and subsequently manipulated to form hydrogels expanded their potential in vitro and in vivo utility; i.e. as culture substrates comparable to collagen or Matrigel, and as injectable materials that fill irregularly-shaped defects. The mechanisms by which ECM hydrogels direct cell behavior and influence remodeling outcomes are only partially understood, but likely include structural and biological signals retained from the native source tissue. The present review describes the utility, formation, and physical and biological characterization of ECM hydrogels. Two examples of clinical application are presented to demonstrate in vivo utility of ECM hydrogels in different organ systems. Finally, new research directions and clinical translation of ECM hydrogels are discussed
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337. Decellularized bone extracellular matrix and human dental pulp stem cells as a construct for bone regeneration
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Paduano, Francesco, Marrelli, Massimo, Alom, Noura, Amer, Mahetab H., White, Lisa J., Shakesheff, Kevin M., Tatullo, Marco, Paduano, Francesco, Marrelli, Massimo, Alom, Noura, Amer, Mahetab H., White, Lisa J., Shakesheff, Kevin M., and Tatullo, Marco
- Abstract
Dental pulp tissue represents a source of mesenchymal stem cells (MSCs) that have a strong differentiation potential towards the osteogenic lineage. The objective of the current study was to examine in vitro osteogenic induction of dental pulp stem cells (DPSCs) cultured on hydrogel scaffolds derived from decellularized bone extracellular matrix (bECM) compared to collagen type I (Col-I), the major component of bone matrix. DPSCs in combination with bECM hydrogels were cultured under three different conditions: basal medium, osteogenic medium and medium supplemented with growth factors (GFs) and cell growth, mineral deposition, gene and protein expression were investigated. The DPSCs/bECM hydrogel constructs cultured in basal medium showed that cells were viable after three weeks and that the expression of runt-related transcription factor 2 (RUNX-2) and bone sialoprotein (BSP) were significantly upregulated in the absence of extra osteogenic inducers compared to Col-I hydrogel scaffolds. In addition, the protein expression levels of BSP and osteocalcin (OCN) were higher on bECM with respect to Col-I hydrogel scaffolds. Furthermore, DPSCs/bECM hydrogels cultured with osteogenic or GFs supplemented medium displayed a higher upregulation of the osteo-specific markers compared to Col-I hydrogels in identical media. Collectively, our results demonstrate that bECM hydrogels might be considered as suitable scaffolds to support osteogenic differentiation of DPSCs
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338. Restoring mucosal barrier function and modifying macrophage phenotype with an extracellular matrix hydrogel: potential therapy for ulcerative colitis
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Keane, Timothy J., Dziki, Jenna, Sobieski, Eric, Smoulder, Adam, Castleton, Arthur A, Turner, Neill J., White, Lisa J., Badylak, Stephen F., Keane, Timothy J., Dziki, Jenna, Sobieski, Eric, Smoulder, Adam, Castleton, Arthur A, Turner, Neill J., White, Lisa J., and Badylak, Stephen F.
- Abstract
Background & Aims: Despite advances in therapeutic options, more than half of all patients with ulcerative colitis (UC) do not achieve long-term remission, many require colectomy, and the disease still has a marked negative impact on quality of life. Extracellular matrix (ECM) bioscaffolds facilitate the functional repair of many soft tissues by mechanisms that include mitigation of pro-inflammatory macrophage phenotype and mobilization of endogenous stem/progenitor cells. The aim of the present study was to determine if an ECM hydrogel therapy could influence outcomes in an inducible rodent model of UC. Methods: The dextran sodium sulfate (DSS)-colitis model was used in male Sprague Dawley rats. Animals were treated via enema with an ECM hydrogel and the severity of colitis was determined by clinical and histologic criteria. Lamina propria cells were isolated and the production of inflammatory mediators was quantified. Mucosal permeability was assessed in-vivo by administering TRITC-dextran and in-vitro using transepithelial electrical resistance (TEER). Results: ECM hydrogel therapy accelerated healing and improved outcome. The hydrogel was adhesive to colonic tissue, which allowed for targeted delivery of the therapy, and resulted in a reduction in clinical and histologic signs of disease. ECM hydrogel facilitated functional improvement of colonic epithelial barrier function and the resolution of the pro-inflammatory state of tissue macrophages. Conclusions: The present study shows that a nonsurgical and nonpharmacologic ECM-based therapy can abate DSS-colitis not by immunosuppression but by promoting phenotypic change in local macrophage phenotype and rapid replacement of the colonic mucosal barrier
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339. The impact of detergents on the tissue decellularization process: a ToF-SIMS study
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White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., Badylak, Stephen F., White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., and Badylak, Stephen F.
- Abstract
Biologic scaffolds are derived from mammalian tissues, which must be decellularized to remove cellular antigens that would otherwise incite an adverse immune response. Although widely used clinically, the optimum balance between cell removal and the disruption of matrix architecture and surface ligand landscape remains a considerable challenge. Here we describe the use of time of flight secondary ion mass spectroscopy (ToF-SIMS) to provide sensitive, molecular specific, localized analysis of detergent decellularized biologic scaffolds. We detected residual detergent fragments, specifically from Triton X-100, sodium deoxycholate and sodium dodecyl sulphate (SDS) in decellularized scaffolds; increased SDS concentrations from 0.1% to 1.0% increased both the intensity of SDS fragments and adverse cell outcomes. We also identified cellular remnants, by detecting phosphate and phosphocholine ions in PAA and CHAPS decellularized scaffolds. The present study demonstrates ToF-SIMS is not only a powerful tool for characterization of biologic scaffold surface molecular functionality, but also enables sensitive assessment of decellularization efficacy.
340. Translational considerations in injectable cell-based therapeutics for neurological applications: concepts, progress and challenges
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Amer, Mahetab H., Rose, Felicity R.A.J., Shakesheff, Kevin M., Modo, Michel, White, Lisa J., Amer, Mahetab H., Rose, Felicity R.A.J., Shakesheff, Kevin M., Modo, Michel, and White, Lisa J.
- Abstract
Significant progress has been made during the past decade towards the clinical adoption of cell- based therapeutics. However, existing cell delivery approaches have shown limited success, with numerous studies showing fewer than 5% of injected cells persisting at the site of injection within days of transplantation. Although consideration is being increasingly given to clinical trial design, little emphasis has been given to tools and protocols used to administer cells. The different behaviours of various cell types, dosing accuracy, precise delivery, and cell retention and viability post-injection are some of the obstacles facing clinical translation. For efficient injectable cell transplantation, accurate characterisation of cellular health post-injection and the development of standardised administration protocols are required. This review provides an overview of the challenges facing effective delivery of cell therapies, examines key studies that have been carried out to investigate injectable cell delivery, and outlines opportunities for translating these findings into more effective cell therapy interventions.
- Full Text
- View/download PDF
341. Surface modification of PdlLGA microspheres with gelatine methacrylate: evaluation of adsorption, entrapment, and oxygen plasma treatment approaches
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Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, Shakesheff, Kevin M., Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, and Shakesheff, Kevin M.
- Abstract
Injectable poly (dl-lactic-co-glycolic acid) (PdlLGA) microspheres are promising candidates as biodegradable controlled release carriers for drug and cell delivery applications; however, they have limited functional groups on the surface to enable dense grafting of tissue specific biocompatible molecules. In this study we have evaluated surface adsorption, entrapment and oxygen plasma treatment as three approaches to modify the surfaces of PdlLGA microspheres with gelatine methacrylate (gel-MA) as a biocompatible and photo cross-linkable macromolecule. Time of flight secondary ion mass spectroscopy (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) were used to detect and quantify gel-MA on the surfaces. Fluorescent and scanning electron microscopies (SEM) were used to image the topographical changes. Human mesenchymal stem cells (hMSCs) of immortalised cell line were cultured on the surface of gel-MA modified PdlLGA microspheres and Presto-Blue assay was used to study the effect of different surface modifications on cell proliferation. Data analysis showed that the oxygen plasma treatment approach resulted in the highest density of gel-MA deposition. This study supports oxygen plasma treatment as a facile approach to modify the surface of injectable PdlLGA microspheres with macromolecules such as gel-MA to enhance proliferation rate of injected cells and potentially enable further grafting of tissue specific molecules.
- Full Text
- View/download PDF
342. Epidemiological waves - types, drivers and modulators in the COVID-19 pandemic
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Harvey, John, Chan, Bryan, Srivastava, Tarun, Zarebski, Alexander E., Dłotko, Paweł, Błaszczyk, Piotr, Parkinson, Rachel H., White, Lisa J., Aguas, Ricardo, Mahdi, Adam, Harvey, John, Chan, Bryan, Srivastava, Tarun, Zarebski, Alexander E., Dłotko, Paweł, Błaszczyk, Piotr, Parkinson, Rachel H., White, Lisa J., Aguas, Ricardo, and Mahdi, Adam
- Abstract
Introduction A discussion of ‘waves’ of the COVID-19 epidemic in different countries is a part of the national conversation for many, but there is no hard and fast means of delineating these waves in the available data and their connection to waves in the sense of mathematical epidemiology is only tenuous. Methods We present an algorithm which processes a general time series to identify substantial, significant and sustained periods of increase in the value of the time series, which could reasonably be described as ‘observed waves’. This provides an objective means of describing observed waves in time series. We use this method to synthesize evidence across different countries to study types, drivers and modulators of waves. Results The output of the algorithm as applied to epidemiological time series related to COVID-19 corresponds to visual intuition and expert opinion. Inspecting the results of individual countries shows how consecutive observed waves can differ greatly with respect to the case fatality ratio. Furthermore, in large countries, a more detailed analysis shows that consecutive observed waves have different geographical ranges. We also show how waves can be modulated by government interventions and find that early implementation of NPIs correlates with a reduced number of observed waves and reduced mortality burden in those waves. Conclusion It is possible to identify observed waves of disease by algorithmic methods and the results can be fruitfully used to analyse the progression of the epidemic.
343. Understanding and managing zoonotic risk in the new livestock industries
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Liverani, Marco, Waage, Jeff, Barnett, Tony, Pfeiffer, Dirk U., Rushton, Jonathan, Rudge, James W., Loevinsohn, Michael E., Scoones, Ian, Smith, Richard D., Cooper, Ben S., White, Lisa J., Goh, Shan, Horby, Peter, Wren, Brendan, Gundogdu, Ozan, Woods, Abigail, Coker, Richard J., Liverani, Marco, Waage, Jeff, Barnett, Tony, Pfeiffer, Dirk U., Rushton, Jonathan, Rudge, James W., Loevinsohn, Michael E., Scoones, Ian, Smith, Richard D., Cooper, Ben S., White, Lisa J., Goh, Shan, Horby, Peter, Wren, Brendan, Gundogdu, Ozan, Woods, Abigail, and Coker, Richard J.
- Abstract
Background: In many parts of the world, livestock production is undergoing a process of rapid intensification. The health implications of this development are uncertain. Intensification creates cheaper products, allowing more people to access animal-based foods. However, some practices associated with intensification may contribute to zoonotic disease emergence and spread, for example the sustained use of antibiotics, concentration of animals in confined units, and long distance and frequent movement of livestock. Objectives: This paper reviews the diverse range of ecological, biological, and socio-economic factors likely to enhance or reduce zoonotic risk, and identifies why improved understanding requires an interdisciplinary approach. A conceptual framework is then offered to guide systematic research on this problem. Discussion: We recommend that interdisciplinary work on zoonotic risk should be able to account for the complexity of risk environments, rather than simple linear causal relations between risk drivers and disease emergence and/or spread. Further, we recommend that interdisciplinary integration is needed at different levels of analysis, from the study of risk environments to the identification of policy options for risk management. Conclusion: Given rapid changes in livestock production systems in developing countries and their potential health implications at the local and global level, the problem we analyse here is of great importance for environmental health and development. While we offer a systematic interdisciplinary approach to understand and address these implications, we recognise that further research is needed to clarify methodological and practical questions arising from the integration of the natural and social sciences.
344. The impact of detergents on the tissue decellularization process: a ToF-SIMS study
- Author
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White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., Badylak, Stephen F., White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., and Badylak, Stephen F.
- Abstract
Biologic scaffolds are derived from mammalian tissues, which must be decellularized to remove cellular antigens that would otherwise incite an adverse immune response. Although widely used clinically, the optimum balance between cell removal and the disruption of matrix architecture and surface ligand landscape remains a considerable challenge. Here we describe the use of time of flight secondary ion mass spectroscopy (ToF-SIMS) to provide sensitive, molecular specific, localized analysis of detergent decellularized biologic scaffolds. We detected residual detergent fragments, specifically from Triton X-100, sodium deoxycholate and sodium dodecyl sulphate (SDS) in decellularized scaffolds; increased SDS concentrations from 0.1% to 1.0% increased both the intensity of SDS fragments and adverse cell outcomes. We also identified cellular remnants, by detecting phosphate and phosphocholine ions in PAA and CHAPS decellularized scaffolds. The present study demonstrates ToF-SIMS is not only a powerful tool for characterization of biologic scaffold surface molecular functionality, but also enables sensitive assessment of decellularization efficacy.
345. Extracellular matrix-derived hydrogels for dental stem cell delivery
- Author
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Viswanath, Aiswarya, Vanacker, Julie, Germain, Loïc, Leprince, Julian G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., des Rieux, Anne, Viswanath, Aiswarya, Vanacker, Julie, Germain, Loïc, Leprince, Julian G., Diogenes, Anibal, Shakesheff, Kevin M., White, Lisa J., and des Rieux, Anne
- Abstract
Decellularized mammalian extracellular matrices (ECM) have been widely accepted as an ideal substrate for repair and remodelling of numerous tissues in clinical and pre-clinical studies. Recent studies have demonstrated the ability of ECM scaffolds derived from site-specific homologous tissues to direct cell differentiation. The present study investigated the suitability of hydrogels derived from different source tissues: bone, spinal cord and dentine, as suitable carriers to deliver human apical papilla derived mesenchymal stem cells (SCAP) for spinal cord regeneration. Bone, spinal cord, and dentine ECM hydrogels exhibited distinct structural, mechanical, and biological characteristics. All three hydrogels supported SCAP viability and proliferation. However, only spinal cord and bone derived hydrogels promoted the expression of neural lineage markers. The specific environment of ECM scaffolds significantly affected the differentiation of SCAP to a neural lineage, with stronger responses observed with spinal cord ECM hydrogels, suggesting that site-specific tissues are more likely to facilitate optimal stem cell behavior for constructive spinal cord regeneration.
346. Translational considerations in injectable cell-based therapeutics for neurological applications: concepts, progress and challenges
- Author
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Amer, Mahetab H., Rose, Felicity R. A. J., Shakesheff, Kevin M., Modo, Michel, White, Lisa J., Amer, Mahetab H., Rose, Felicity R. A. J., Shakesheff, Kevin M., Modo, Michel, and White, Lisa J.
- Abstract
Significant progress has been made during the past decade towards the clinical adoption of cell-based therapeutics. However, existing cell-delivery approaches have shown limited success, with numerous studies showing fewer than 5% of injected cells persisting at the site of injection within days of transplantation. Although consideration is being increasingly given to clinical trial design, little emphasis has been given to tools and protocols used to administer cells. The different behaviours of various cell types, dosing accuracy, precise delivery, and cell retention and viability post-injection are some of the obstacles facing clinical translation. For efficient injectable cell transplantation, accurate characterisation of cellular health post-injection and the development of standardised administration protocols are required. This review provides an overview of the challenges facing effective delivery of cell therapies, examines key studies that have been carried out to investigate injectable cell delivery, and outlines opportunities for translating these findings into more effective cell-therapy interventions.
347. Surface modification of P dl LGA microspheres with gelatine methacrylate: Evaluation of adsorption, entrapment, and oxygen plasma treatment approaches
- Author
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Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, Shakesheff, Kevin M., Baki, Abdulrahman, Rahman, Cheryl V., White, Lisa J., Scurr, David J., Qutachi, Omar, and Shakesheff, Kevin M.
- Abstract
Injectable poly (dl-lactic-co-glycolic acid) (PdlLGA) microspheres are promising candidates as biodegradable controlled release carriers for drug and cell delivery applications; however, they have limited functional groups on the surface to enable dense grafting of tissue specific biocompatible molecules. In this study we have evaluated surface adsorption, entrapment and oxygen plasma treatment as three approaches to modify the surfaces of PdlLGA microspheres with gelatine methacrylate (gel-MA) as a biocompatible and photo cross-linkable macromolecule. Time of flight secondary ion mass spectroscopy (TOF SIMS) and X-ray photoelectron spectroscopy (XPS) were used to detect and quantify gel-MA on the surfaces. Fluorescent and scanning electron microscopies (SEM) were used to image the topographical changes. Human mesenchymal stem cells (hMSCs) of immortalised cell line were cultured on the surface of gel-MA modified PdlLGA microspheres and Presto-Blue assay was used to study the effect of different surface modifications on cell proliferation. Data analysis showed that the oxygen plasma treatment approach resulted in the highest density of gel-MA deposition. This study supports oxygen plasma treatment as a facile approach to modify the surface of injectable PdlLGA microspheres with macromolecules such as gel-MA to enhance proliferation rate of injected cells and potentially enable further grafting of tissue specific molecules.
348. The impact of detergents on the tissue decellularization process: a ToF-SIMS study
- Author
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White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., Badylak, Stephen F., White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., and Badylak, Stephen F.
- Abstract
Biologic scaffolds are derived from mammalian tissues, which must be decellularized to remove cellular antigens that would otherwise incite an adverse immune response. Although widely used clinically, the optimum balance between cell removal and the disruption of matrix architecture and surface ligand landscape remains a considerable challenge. Here we describe the use of time of flight secondary ion mass spectroscopy (ToF-SIMS) to provide sensitive, molecular specific, localized analysis of detergent decellularized biologic scaffolds. We detected residual detergent fragments, specifically from Triton X-100, sodium deoxycholate and sodium dodecyl sulphate (SDS) in decellularized scaffolds; increased SDS concentrations from 0.1% to 1.0% increased both the intensity of SDS fragments and adverse cell outcomes. We also identified cellular remnants, by detecting phosphate and phosphocholine ions in PAA and CHAPS decellularized scaffolds. The present study demonstrates ToF-SIMS is not only a powerful tool for characterization of biologic scaffold surface molecular functionality, but also enables sensitive assessment of decellularization efficacy.
349. The impact of detergents on the tissue decellularization process: a ToF-SIMS study
- Author
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White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., Badylak, Stephen F., White, Lisa J., Taylor, Adam J., Faulk, Denver M., Keane, Timothy J., Saldin, Lindsey T., Reing, Janet E., Swinehart, Ilea T., Turner, Neill J., Ratner, Buddy D., and Badylak, Stephen F.
- Abstract
Biologic scaffolds are derived from mammalian tissues, which must be decellularized to remove cellular antigens that would otherwise incite an adverse immune response. Although widely used clinically, the optimum balance between cell removal and the disruption of matrix architecture and surface ligand landscape remains a considerable challenge. Here we describe the use of time of flight secondary ion mass spectroscopy (ToF-SIMS) to provide sensitive, molecular specific, localized analysis of detergent decellularized biologic scaffolds. We detected residual detergent fragments, specifically from Triton X-100, sodium deoxycholate and sodium dodecyl sulphate (SDS) in decellularized scaffolds; increased SDS concentrations from 0.1% to 1.0% increased both the intensity of SDS fragments and adverse cell outcomes. We also identified cellular remnants, by detecting phosphate and phosphocholine ions in PAA and CHAPS decellularized scaffolds. The present study demonstrates ToF-SIMS is not only a powerful tool for characterization of biologic scaffold surface molecular functionality, but also enables sensitive assessment of decellularization efficacy.
350. Strengths and opportunities in research into extracellular matrix ageing: A consultation with the ECMage research community.
- Author
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Dalby, Matthew J., Pekovic‐Vaughan, Vanja, Shanley, Daryl P., Swift, Joe, White, Lisa J., and Canty‐Laird, Elizabeth G.
- Subjects
- *
EXTRACELLULAR matrix , *SCIENTIFIC community , *BIOFILMS , *RESEARCH personnel , *INTERDISCIPLINARY research , *MEDICAL research - Abstract
Ageing causes progressive decline in metabolic, behavioural, and physiological functions, leading to a reduced health span. The extracellular matrix (ECM) is the three‐dimensional network of macromolecules that provides our tissues with structure and biomechanical resilience. Imbalance between damage and repair/regeneration causes the ECM to undergo structural deterioration with age, contributing to age‐associated pathology. The ECM 'Ageing Across the Life Course' interdisciplinary research network (ECMage) was established to bring together researchers in the United Kingdom, and internationally, working on the emerging field of ECM ageing. Here we report on a consultation at a joint meeting of ECMage and the Medical Research Council / Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing, held in January 2023, in which delegates analysed the key questions and research opportunities in the field of ECM ageing. We examine fundamental biological questions, enabling technologies, systems of study and emerging in vitro and in silico models, alongside consideration of the broader challenges facing the field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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