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1.
Dev Psychopathol ; 35(3): 1382-1389, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-34924093

RESUMO

Altered autobiographical memory (ABM) processing characterizes some individuals with experiences of childhood maltreatment. This fMRI study of ABM processing evaluated potential developmental plasticity in neural functioning following maltreatment. Adolescents with (N = 19; MT group) and without (N = 18; Non-MT group) documented childhood maltreatment recalled specific ABMs in response to emotionally valenced cue words during fMRI at baseline (age 12.71 ± 1.48) and follow-up (14.88 ± 1.53 years). Psychological assessments were collected at both timepoints. Longitudinal analyses were carried out with BOLD signal changes during ABM recall and psychopathology to investigate change over time. In both groups there was relative stability of the ABM brain network, with some developmental maturational changes observed in cortical midline structures (ventromedial PFC (vmPFC), posterior cingulate cortex (pCC), and retrosplenial cortex (rSC). Significantly increased activation of the right rSC was observed only in the MT group, which was associated with improved psychological functioning. Baseline group differences in relation to hippocampal functioning, were not detected at follow-up. This study provides preliminary empirical evidence of functional developmental plasticity in children with documented maltreatment experience using fMRI. This suggests that altered patterns of brain function, associated with maltreatment experience, are not fixed and may reflect the potential to track a neural basis of resilience.


Assuntos
Imageamento por Ressonância Magnética , Memória Episódica , Adolescente , Criança , Humanos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Rememoração Mental/fisiologia , Plasticidade Neuronal
2.
Artif Organs ; 47(9): 1531-1538, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37032625

RESUMO

BACKGROUND: Eulerian and Lagrangian power-law formulations are both widely used for computational fluid dynamics (CFD) to predict flow-induced hemolysis in blood-contacting medical devices. Both are based on the same empirical power-law correlation between hemolysis and the shear stress and exposure time. In the Lagrangian approach, blood damage is predicted by tracking both the stress and exposure time along a finite number of pathlines in the domain. In the Eulerian approach, a scalar transport equation is solved for a time-linearized damage index within the entire domain. Previous analytical work has demonstrated that there is a fundamental problem with the treatment of exposure time in the Eulerian model formulation such that the only condition under which the model correctly represents the true exposure time is in a flow field with no streamwise velocity variation. However, the practical implications of this limitation have yet to be thoroughly investigated. METHODS: In this study, we demonstrate the inaccuracy of Eulerian hemolysis power-law model predictions due to the erroneous treatment of exposure time by systematically considering four benchmark test cases with increasing degrees of flow acceleration: Poiseuille flow through a straight tube, inclined Couette flow, and flow through a converging tube with two different convergence ratios. RESULTS: Compared with Lagrangian predictions, we show that, as flow acceleration becomes more pronounced, the resultant inaccuracy in the Eulerian predictions increases. For the inclined Couette flow case, there is a small degree of flow acceleration that yields a discrepancy in the range of 10% between Lagrangian and Eulerian predictions. For flows with a larger degree of acceleration, as occurs in the converging tube flow cases, the discrepancy is considerably larger (up to 257%). CONCLUSION: The inaccuracy of hemolysis predictions due to the erroneous treatment of exposure time in the Eulerian power-law model can be significant when there is streamwise velocity variation in the flow field. These results may partially explain the extremely large variability in CFD hemolysis predictions reported in the literature between Lagrangian and Eulerian models.


Assuntos
Hemólise , Modelos Cardiovasculares , Humanos , Simulação por Computador , Velocidade do Fluxo Sanguíneo
3.
Public Health ; 225: 343-352, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37979311

RESUMO

INTRODUCTION: The COVID-19 pandemic has prompted governments internationally to consider strengthening their public health systems. To support the work of Ireland's Public Health Reform Expert Advisory Group, the Health Information and Quality Authority, an independent governmental agency, was asked to describe the lessons learnt regarding the public health response to COVID-19 internationally and the applicability of this response for future pandemic preparedness. METHODS: Semi-structured interviews with key public health representatives from nine countries were conducted. Interviews were conducted in March and April 2022 remotely via Zoom and were recorded. Notes were taken by two researchers, and a thematic analysis undertaken. RESULTS: Lessons learnt from the COVID-19 pandemic related to three main themes: 1) setting policy; 2) delivering public health interventions; and 3) providing effective communication. Real-time surveillance, evidence synthesis, and cross-sectoral collaboration were reported as essential for policy setting; it was noted that having these functions established prior to the pandemic would lead to a more efficient implementation in a health emergency. Delivering public health interventions such as testing, contact tracing, and vaccination were key to limiting and or mitigating the spread of the SARS-CoV-2 virus. However, a number of challenges were highlighted such as staff capacity and burnout, delays in vaccination procurement, and reduced delivery of regular healthcare services. Clear, consistent, and regular communication of the scientific evidence was key to engaging citizens with mitigation strategies. However, these communication strategies had to compete with an infodemic of information being circulated, particularly through social media. CONCLUSIONS: Overall, functions relating to policy setting, public health interventions, and communication are key to pandemic response. Ideally, these should be established in the preparedness phase so that they can be rapidly scaled-up during a pandemic.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , SARS-CoV-2 , Pandemias/prevenção & controle , Reforma dos Serviços de Saúde , Saúde Pública
4.
J Biomech Eng ; 143(1)2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32793961

RESUMO

Flow-induced hemolysis remains a concern for blood-contacting devices, and computer-based prediction of hemolysis could facilitate faster and more economical refinement of such devices. While evaluation of convergence of velocity fields obtained by computational fluid dynamics (CFD) simulations has become conventional, convergence of hemolysis calculations is also essential. In this paper, convergence of the power-law hemolysis model is compared for simple flows, including pathlines with exponentially increasing and decreasing stress, in gradually expanding and contracting Couette flows, in a sudden radial expansion and in the Food and Drug Administration (FDA) channel. In the exponential cases, convergence along a pathline required from one to tens of thousands of timesteps, depending on the exponent. Greater timesteps were required for rapidly increasing (large exponent) stress and for rapidly decreasing (small exponent) stress. Example pathlines in the Couette flows could be fit with exponential curves, and convergence behavior followed the trends identified from the exponential cases. More complex flows, such as in the radial expansion and the FDA channel, increase the likelihood of encountering problematic pathlines. For the exponential cases, comparison of converged hemolysis values with analytical solutions demonstrated that the error of the converged solution may exceed 10% for both rapidly decreasing and rapidly increasing stress.


Assuntos
Hidrodinâmica , Modelos Cardiovasculares , Simulação por Computador , Hemólise
5.
J Biomech Eng ; 142(2)2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31343659

RESUMO

It has been hypothesized that early and rapid filtration of blood from cerebrospinal fluid (CSF) in postsubarachnoid hemorrhage patients may reduce hospital stay and related adverse events. In this study, we formulated a subject-specific computational fluid dynamics (CFD) model to parametrically investigate the impact of a novel dual-lumen catheter-based CSF filtration system, the Neurapheresis™ system (Minnetronix Neuro, Inc., St. Paul, MN), on intrathecal CSF dynamics. The operating principle of this system is to remove CSF from one location along the spine (aspiration port), externally filter the CSF routing the retentate to a waste bag, and return permeate (uncontaminated CSF) to another location along the spine (return port). The CFD model allowed parametric simulation of how the Neurapheresis system impacts intrathecal CSF velocities and steady-steady streaming under various Neurapheresis flow settings ranging from 0.5 to 2.0 ml/min and with a constant retentate removal rate of 0.2 ml/min simulation of the Neurapheresis system were compared to a lumbar drain simulation with a typical CSF removal rate setting of 0.2 ml/min. Results showed that the Neurapheresis system at a maximum flow of 2.0 ml/min increased average steady streaming CSF velocity 2× in comparison to lumbar drain (0.190 ± 0.133 versus 0.093 ± 0.107 mm/s, respectively). This affect was localized to the region within the Neurapheresis flow loop. The mean velocities introduced by the flow loop were relatively small in comparison to normal cardiac-induced CSF velocities.


Assuntos
Simulação por Computador , Hidrodinâmica , Modelos Biológicos , Coluna Vertebral
6.
Artif Organs ; 43(7): 681-687, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30656703

RESUMO

Two limitations have been discovered in the derivation of the Eulerian method of hemolysis prediction using a linearized blood damage function. First is that in the transformation from the Lagrangian material volume of the original power-law model to a fixed Eulerian control volume, the spatial dependence of duration of exposure to fluid stress was neglected. This omission has the implication that the Eulerian method as reported is valid only for steady, uniaxial flow in which velocity is constant along streamlines. The second issue is related to linearization, which involves distributing an exponent across an integral. This operation is valid only for limited conditions that include the exponent being unity (which is not the case for any power-law hemolysis models) or the blood damage function being constant throughout the flow regime. These constraints severely restrict the applicability of the Eulerian method. An example problem is presented that demonstrates that the source term of the Eulerian method as reported does not account for differences in velocity between 2 similar flows. Correcting the source term to match the hemolysis prediction to that of the original, unlinearized method requires an analytical description of the flow field that may not be easily obtained for the complex flows in some cardiovascular devices.


Assuntos
Simulação por Computador , Hemólise , Modelos Cardiovasculares , Estresse Mecânico , Coração Auxiliar/efeitos adversos , Humanos , Modelos Lineares
7.
Clin Exp Allergy ; 48(4): 452-463, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29193486

RESUMO

BACKGROUND: Fish is a well-recognized cause of food allergy and anaphylaxis. The evolutionary and taxonomic diversity of the various consumed fish species pose a challenge in the identification and characterization of the major fish allergens critical for reliable diagnostics. Globally, fish is a rising cause of food allergy complicated by a large under-investigated variety of species as well as increasing global tourism and trade. This is the first comprehensive study on allergen profiles of heat-processed fish from Vietnam. OBJECTIVE: The aim of this study was to identify the major heat-stable allergens from frequently exported Asia-Pacific freshwater and marine fish and to characterize the major allergen parvalbumin (PV) from one of the most consumed and exported fish species from Asia, the Indian mackerel (Rastrelliger kanagurta). METHODS: Heated protein extracts from 33 fish species were separated by gel electrophoresis. PV isoforms were identified by immunoblotting utilizing 3 different PV-specific monoclonal and polyclonal antibodies and further characterized by mass spectrometry. IgE reactivity was investigated using sera from 21 patients with confirmed fish allergy. RESULTS: Heat-stable IgE-reactive PVs, with up to 5 isoforms per species, were identified in all 33 analysed fish species. In the Indian mackerel, 7 PV isoforms were identified by 2D-gel electrophoresis combined with mass spectrometric analyses. The amino acid sequence deduced from cDNA of the most expressed isoform showed a high identity (>90%) to PVs from 2 other mackerel species. CONCLUSIONS AND CLINICAL RELEVANCE: Different PVs were identified as the major heat-stable allergens in all 33 analysed freshwater and marine fish species from Vietnam, many of which are exported world-wide and 21 species that have never been investigated before. The Indian mackerel PV represents a novel fish allergen, now officially registered as Ras k 1. Improved diagnostics for fish allergy against Asia-Pacific species should be developed with focus on PV.


Assuntos
Alérgenos/análise , Proteínas de Peixes/análise , Hipersensibilidade Alimentar/imunologia , Parvalbuminas/imunologia , Perciformes , Alérgenos/imunologia , Animais , Proteínas de Peixes/imunologia , Peixes , Humanos
8.
Nature ; 488(7413): 633-7, 2012 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-22932387

RESUMO

Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.


Assuntos
Sedimentos Geológicos/química , Metano/análise , Regiões Antárticas , Retroalimentação , Gases/análise , Gases/química , Gases/metabolismo , Sedimentos Geológicos/microbiologia , Aquecimento Global , Camada de Gelo , Metano/biossíntese , Metano/química , Pressão , Solubilidade , Temperatura , Incerteza
9.
J Biomech Eng ; 140(8)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30003260

RESUMO

Cerebrospinal fluid (CSF) dynamics are thought to play a vital role in central nervous system (CNS) physiology. The objective of this study was to investigate the impact of spinal cord (SC) nerve roots (NR) on CSF dynamics. A subject-specific computational fluid dynamics (CFD) model of the complete spinal subarachnoid space (SSS) with and without anatomically realistic NR and nonuniform moving dura wall deformation was constructed. This CFD model allowed detailed investigation of the impact of NR on CSF velocities that is not possible in vivo using magnetic resonance imaging (MRI) or other noninvasive imaging methods. Results showed that NR altered CSF dynamics in terms of velocity field, steady-streaming, and vortical structures. Vortices occurred in the cervical spine around NR during CSF flow reversal. The magnitude of steady-streaming CSF flow increased with NR, in particular within the cervical spine. This increase was located axially upstream and downstream of NR due to the interface of adjacent vortices that formed around NR.


Assuntos
Líquido Cefalorraquidiano/metabolismo , Hidrodinâmica , Modelos Anatômicos , Raízes Nervosas Espinhais/anatomia & histologia , Raízes Nervosas Espinhais/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Modelagem Computacional Específica para o Paciente , Raízes Nervosas Espinhais/diagnóstico por imagem , Espaço Subaracnóideo/anatomia & histologia , Espaço Subaracnóideo/diagnóstico por imagem , Espaço Subaracnóideo/fisiologia , Adulto Jovem
10.
Clin Exp Allergy ; 47(3): 300-312, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28117510

RESUMO

Allergy to bony fish is common and probably increasing world-wide. The major heat-stable pan-fish allergen, parvalbumin (PV), has been identified and characterized for numerous fish species. In contrast, there are very few reports of allergic reactions to cartilaginous fish despite widespread consumption. The molecular basis for this seemingly low clinical cross-reactivity between these two fish groups has not been elucidated. PV consists of two distinct protein lineages, α and ß. The α-lineage of this protein is predominant in muscle tissue of cartilaginous fish (Chondrichthyes), while ß-PV is abundant in muscle tissue of bony fish (Osteichthyes). The low incidence of allergic reactions to ingested rays and sharks is likely due to the lack of molecular similarity, resulting in reduced immunological cross-reactivity between the two PV lineages. Structurally and physiologically, both protein lineages are very similar; however, the amino acid homology is very low with 47-54%. Furthermore, PV from ancient fish species such as the coelacanth demonstrates 62% sequence homology to leopard shark α-PV and 70% to carp ß-PV. This indicates the extent of conservation of the PV isoforms lineages across millennia. This review highlights prevalence data on fish allergy and sensitization to fish, and details the molecular diversity of the two protein lineages of the major fish allergen PV among different fish groups, emphasizing the immunological and clinical differences in allergenicity.


Assuntos
Alérgenos/imunologia , Peixes/imunologia , Hipersensibilidade Alimentar/imunologia , Alérgenos/química , Animais , Reações Cruzadas/imunologia , Exposição Ambiental , Epitopos/imunologia , Peixes/classificação , Hipersensibilidade Alimentar/diagnóstico , Hipersensibilidade Alimentar/epidemiologia , Hipersensibilidade Alimentar/terapia , Humanos , Imunoglobulina E/imunologia
11.
Phys Rev Lett ; 117(14): 147803, 2016 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-27740797

RESUMO

We have studied the motion of polyhedral oligomeric silsesquioxane (POSS) nanoparticles modified with poly(ethylene glycol) (PEG) arms immersed in PEG matrices of different molecular weight. Employing neutron spin echo spectroscopy in combination with pulsed field gradient (PFG) NMR we found the following. (i) For entangled matrices the center of mass mean square displacement (MSD) of the PEG-POSS particles is subdiffusive following a t^{0.56} power law. (ii) The diffusion coefficient as well as the crossover to Fickian diffusion is independent of the matrix molecular weight and takes place as soon as the center of mass has moved a distance corresponding to the particle radius-this holds also for unentangled hosts. (iii) For the entangled matrices Rubinstein's scaling theory is validated; however, the numbers indicate that beyond Rouse friction the entanglement constraints appear to strongly increase the effective friction even on the nanoparticle length scale imposing a caveat on the interpretation of microrheological experiments. (iv) The oligomer decorated PEG-POSS particles exhibit the dynamics of a Gaussian star with an internal viscosity that rises with an increase of the host molecular weight.

12.
J Biomech Eng ; 138(12)2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27657486

RESUMO

Hemolysis (damage to red blood cells) is a long-standing problem in blood contacting devices, and its prediction has been the goal of considerable research. The most popular model relating hemolysis to fluid stresses is the power-law model, which was developed from experiments in pure shear only. In the absence of better data, this model has been extended to more complex flows by replacing the shear stress in the power-law equation with a von Mises-like scalar stress. While the validity of the scalar stress also remains to be confirmed, inconsistencies exist in its application, in particular, two forms that vary by a factor of 2 have been used. This article will clarify the proper extension of the power law to complex flows in a way that maintains correct results in the limit of pure shear.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Membrana Eritrocítica/fisiologia , Eritrócitos/fisiologia , Hemólise/fisiologia , Modelos Cardiovasculares , Reologia/métodos , Algoritmos , Células Cultivadas , Força Compressiva/fisiologia , Simulação por Computador , Humanos , Fluidez de Membrana/fisiologia , Dinâmica não Linear , Resistência ao Cisalhamento/fisiologia , Estresse Mecânico
13.
Antimicrob Agents Chemother ; 58(10): 5784-94, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25049242

RESUMO

Coadministration of dihydroartemisinin-piperaquine (DHA-PQ) with fat may improve bioavailability and antimalarial efficacy, but it might also increase toxicity. There have been no studies of these potential effects in the pediatric age group. The tolerability, safety, efficacy, and pharmacokinetics of DHA-PQ administered with or without 8.5 g fat were investigated in 30 Papua New Guinean children aged 5 to 10 years diagnosed with uncomplicated falciparum malaria. Three daily 2.5:11.5-mg-base/kg doses were given with water (n = 14, group A) or milk (n = 16, group B), with regular clinical/laboratory assessment and blood sampling over 42 days. Plasma PQ was assayed by high-performance liquid chromatography with UV detection, and DHA was assayed using liquid chromatography-mass spectrometry. Compartmental pharmacokinetic models for PQ and DHA were developed using a population-based approach. DHA-PQ was generally well tolerated, and initial fever and parasite clearance were prompt. There were no differences in the areas under the concentration-time curve (AUC0-∞) for PQ (median, 41,906 versus 36,752 µg · h/liter in groups A and B, respectively; P = 0.24) or DHA (4,047 versus 4,190 µg · h/liter; P = 0.67). There were also no significant between-group differences in prolongation of the corrected electrocardiographic QT interval (QTc) initially during follow-up, but the QTc tended to be higher in group B children at 24 h (mean ± standard deviation [SD], 15 ± 10 versus 6 ± 15 ms(0.5) in group A, P = 0.067) and 168 h (10 ± 18 versus 1 ± 23 ms(0.5), P = 0.24) when plasma PQ concentrations were relatively low. A small amount of fat does not change the bioavailability of DHA-PQ in children, but a delayed persistent effect on ventricular repolarization cannot be excluded.


Assuntos
Antimaláricos/efeitos adversos , Antimaláricos/farmacocinética , Artemisininas/efeitos adversos , Artemisininas/farmacocinética , Malária/sangue , Quinolinas/efeitos adversos , Quinolinas/farmacocinética , Antimaláricos/administração & dosagem , Antimaláricos/uso terapêutico , Artemisininas/administração & dosagem , Criança , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Malária/tratamento farmacológico , Masculino , Quinolinas/administração & dosagem
15.
Phys Rev Lett ; 113(16): 168302, 2014 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-25361284

RESUMO

We present neutron scattering data on the structure and dynamics of melts from polyethylene oxide rings with molecular weights up to ten times the entanglement mass of the linear counterpart. The data reveal a very compact conformation displaying a structure approaching a mass fractal, as hypothesized by recent simulation work. The dynamics is characterized by a fast Rouse relaxation of subunits (loops) and a slower dynamics displaying a lattice animal-like loop displacement. The loop size is an intrinsic property of the ring architecture and is independent of molecular weight. This is the first experimental observation of the space-time evolution of segmental motion in ring polymers illustrating the dynamic consequences of their topology that is unique among all polymeric systems of any other known architecture.


Assuntos
Modelos Químicos , Polietilenoglicóis/química , Fractais , Peso Molecular , Difração de Nêutrons , Termodinâmica
16.
J Magn Reson Imaging ; 39(6): 1477-85, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24123721

RESUMO

PURPOSE: To validate conventional phase-contrast MRI (PC-MRI) measurements of steady and pulsatile flows through stenotic phantoms with various degrees of narrowing at Reynolds numbers mimicking flows in the human iliac artery using stereoscopic particle image velocimetry (SPIV) as gold standard. MATERIALS AND METHODS: A series of detailed experiments are reported for validation of MR measurements of steady and pulsatile flows with SPIV and CFD on three different stenotic models with 50%, 74%, and 87% area occlusions at three sites: two diameters proximal to the stenosis, at the throat, and two diameters distal to the stenosis. RESULTS: Agreement between conventional spin-warp PC-MRI with Cartesian read-out and SPIV was demonstrated for both steady and pulsatile flows with mean Reynolds numbers of 130, 160, and 190 at the inlet by evaluating the linear regression between the two methods. The analysis revealed a correlation coefficient of > 0.99 and > 0.96 for steady and pulsatile flows, respectively. Additionally, it was found that the most accurate measures of flow by the sequence were at the throat of the stenosis (error < 5% for both steady and pulsatile mean flows). The flow rate error distal to the stenosis was primarily found to be a function of narrowing severity including dependence on proper Venc selection. CONCLUSION: SPIV and CFD provide excellent approaches to in vitro validation of new or existing PC-MRI flow measurement techniques.


Assuntos
Hidrodinâmica , Imageamento por Ressonância Magnética/métodos , Fluxo Pulsátil , Reologia/métodos , Velocidade do Fluxo Sanguíneo , Constrição Patológica , Técnicas In Vitro , Magnetismo , Imagens de Fantasmas , Reprodutibilidade dos Testes
17.
Public Health ; 128(11): 1017-22, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25443131

RESUMO

OBJECTIVES: In the UK, women aged 50-70 are offered breast cancer screening every three years. Screening participation rates in London have been particularly low. Low rates have been associated with low socio-economic status, and some ethnic groups have been observed to be underserved by cancer screening. This paper reports on a telephone reminder intervention in London Newham, an area of high deprivation and ethnic diversity. STUDY DESIGN: Observational study of planned intervention. METHODS: Women invited for breast screening were telephoned to confirm receipt of the invitation letter, remind invitees of their upcoming appointment, and to provide further information. Aggregate data at general practice level on invitation to and attendance at breast screening and on numbers reached by telephone were analysed by logistic regression. RESULTS: For the 29 participating GP practices (10,928 invitees) overall uptake in 2010 was higher compared to the previous screening round in 2007 (67% vs. 51%; p < 0.001). On average 59% of invitees were reached by the reminder calls. A 10% increase in women reached resulted in an 8% increase in the odds of women attending their screening appointment (95% CI: 5%-11%), after adjusting for 2007 attendance rates. Practices with a higher proportion of South Asian women were associated with a larger uptake adjusted for 2007 uptake and population reached by the telephone intervention, (4% increase in odds of attendance per 10% increase in South Asian population, CI 1%-7%, p = 0.003) while practices with a higher proportion of black women were associated with a smaller uptake similarly adjusted. (11% decrease in odds of attendance per 10% increase in black population, CI 9%-16%, p < 0.001). CONCLUSIONS: A language- and culture-sensitive programme of reminder calls substantially improved breast cancer screening uptake.


Assuntos
Neoplasias da Mama/prevenção & controle , Detecção Precoce de Câncer/estatística & dados numéricos , Promoção da Saúde/métodos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Disseminação de Informação/métodos , Sistemas de Alerta , Telefone , Idoso , Diversidade Cultural , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Londres , Pessoa de Meia-Idade , Avaliação de Programas e Projetos de Saúde , Fatores Socioeconômicos , Medicina Estatal
18.
Artif Organs ; 37(3): 256-66, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23419169

RESUMO

Hemolysis caused by flow in hypodermic needles interferes with a number of tests on blood samples drawn by venipuncture, including assays for metabolites, electrolytes, and enzymes, causes discomfort during dialysis sessions, and limits transfusion flow rates. To evaluate design modifications to address this problem, as well as hemolysis issues in other cardiovascular devices, computational fluid dynamics (CFD)-based prediction of hemolysis has potential for reducing the time and expense for testing of prototypes. In this project, three CFD-integrated blood damage models were applied to flow-induced hemolysis in 16-G needles and compared with experimental results, which demonstrated that a modified needle with chamfered entrance increased hemolysis, while a rounded entrance decreased hemolysis, compared with a standard needle with sharp entrance. After CFD simulation of the steady-state velocity field, the time histories of scalar stress along a grid of streamlines were calculated. A strain-based cell membrane failure model and two empirical power-law blood damage models were used to predict hemolysis on each streamline. Total hemolysis was calculated by weighting the predicted hemolysis along each streamline by the flow rate along each streamline. The results showed that only the strain-based blood damage model correctly predicted increased hemolysis in the beveled needle and decreased hemolysis in the rounded needle, while the power-law models predicted the opposite trends.


Assuntos
Hemólise , Hemorreologia , Injeções/instrumentação , Agulhas , Velocidade do Fluxo Sanguíneo , Simulação por Computador , Desenho de Equipamento , Humanos , Injeções/efeitos adversos , Teste de Materiais , Modelos Cardiovasculares , Estresse Mecânico , Fatores de Tempo
19.
Eur J Appl Physiol ; 113(8): 1919-37, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23539439

RESUMO

Mathematical modeling represents an important tool for analyzing cardiovascular function during spaceflight. This review describes how modeling of the cardiovascular system can contribute to space life science research and illustrates this process via modeling efforts to study postflight orthostatic intolerance (POI), a key issue for spaceflight. Examining this application also provides a context for considering broader applications of modeling techniques to the challenges of bioastronautics. POI, which affects a large fraction of astronauts in stand tests upon return to Earth, presents as dizziness, fainting and other symptoms, which can diminish crew performance and cause safety hazards. POI on the Moon or Mars could be more critical. In the field of bioastronautics, POI has been the dominant application of cardiovascular modeling for more than a decade, and a number of mechanisms for POI have been investigated. Modeling approaches include computational models with a range of incorporated factors and hemodynamic sophistication, and also physical models tested in parabolic and orbital flight. Mathematical methods such as parameter sensitivity analysis can help identify key system mechanisms. In the case of POI, this could lead to more effective countermeasures. Validation is a persistent issue in modeling efforts, and key considerations and needs for experimental data to synergistically improve understanding of cardiovascular responses are outlined. Future directions in cardiovascular modeling include subject-specific assessment of system status, as well as research on integrated physiological responses, leading, for instance, to assessment of subject-specific susceptibility to POI or effects of cardiovascular alterations on muscular, vision and cognitive function.


Assuntos
Modelos Cardiovasculares , Voo Espacial , Animais , Humanos , Intolerância Ortostática/fisiopatologia
20.
Eur J Appl Physiol ; 113(7): 1645-54, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23073848

RESUMO

Regulatory systems are affected in space by exposure to weightlessness, high-energy radiation or other spaceflight-induced changes. The impact of spaceflight occurs across multiple scales and systems. Exploring such interactions and interdependencies via an integrative approach provides new opportunities for elucidating these complex responses. This paper argues the case for increased emphasis on integration, systematically archiving, and the coordination of past, present and future space and ground-based analogue experiments. We also discuss possible mechanisms for such integration across disciplines and missions. This article then introduces several discipline-specific reviews that show how such integration can be implemented. Areas explored include: adaptation of the central nervous system to space; cerebral autoregulation and weightlessness; modelling of the cardiovascular system in space exploration; human metabolic response to spaceflight; and exercise, artificial gravity, and physiologic countermeasures for spaceflight. In summary, spaceflight physiology research needs a conceptual framework that extends problem solving beyond disciplinary barriers. Administrative commitment and a high degree of cooperation among investigators are needed to further such a process. Well-designed interdisciplinary research can expand opportunities for broad interpretation of results across multiple physiological systems, which may have applications on Earth.


Assuntos
Adaptação Fisiológica/fisiologia , Estudos Interdisciplinares , Voo Espacial , Meio Ambiente Extraterreno , Humanos , Ausência de Peso
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