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1.
BMJ Open Respir Res ; 11(1)2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38697677

RESUMO

BACKGROUND: Singing for lung health (SLH) is an arts-based breathing control and movement intervention for people with long-term respiratory conditions, intended to improve symptoms and quality of life. Online, remotely delivered programmes might improve accessibility; however, no previous studies have assessed the effectiveness of this approach. METHODS: We conducted an assessor-blind randomised controlled trial comparing the impact of 12 weeks of once-weekly online SLH sessions against usual care on health-related quality of life, assessed using the RAND 36-Item Short Form Health Survey (SF-36) Mental Health Composite (MHC) and Physical Health Composite (PHC) scores. RESULTS: We enrolled 115 people with stable chronic obstructive pulmonary disease (COPD), median (IQR) age 69 (62-74), 56.5% females, 80% prior pulmonary rehabilitation, Medical Research Council dyspnoea scale 4 (3-4), forced expiratory volume in 1 s % predicted 49 (35-63). 50 participants in each arm completed the study. The intervention arm experienced improvements in physical but not mental health components of RAND SF-36; PHC (regression coefficient (95% CI): 1.77 (95% CI 0.11 to 3.44); p=0.037), but not MHC (0.86 (95% CI -1.68 to 3.40); p=0.504). A prespecified responder analysis based on achieving a 10% improvement from baseline demonstrated a response rate for PHC of 32% in the SLH arm and 12.7% for usual care (p=0.024). A between-group difference in responder rate was not found in relation to the MHC (19.3% vs 25.9%; p=0.403). DISCUSSION AND CONCLUSION: A 12-week online SLH programme can improve the physical component of quality of life for people with COPD, but the overall effect is relatively modest compared with the impact seen in research using face-to-face group sessions. Further work on the content, duration and dose of online interventions may be useful. TRIAL REGISTRATION NUMBER: NCT04034212.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Qualidade de Vida , Canto , Humanos , Doença Pulmonar Obstrutiva Crônica/terapia , Doença Pulmonar Obstrutiva Crônica/reabilitação , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Resultado do Tratamento , Pulmão/fisiopatologia , Volume Expiratório Forçado , Exercícios Respiratórios/métodos , Método Simples-Cego
2.
Front Immunol ; 14: 1201658, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37520564

RESUMO

The airway epithelium comprises of different cell types and acts as a physical barrier preventing pathogens, including inhaled particles and microbes, from entering the lungs. Goblet cells and submucosal glands produce mucus that traps pathogens, which are expelled from the respiratory tract by ciliated cells. Basal cells act as progenitor cells, differentiating into different epithelial cell types, to maintain homeostasis following injury. Adherens and tight junctions between cells maintain the epithelial barrier function and regulate the movement of molecules across it. In this review we discuss how abnormal epithelial structure and function, caused by chronic injury and abnormal repair, drives airway disease and specifically asthma and chronic obstructive pulmonary disease (COPD). In both diseases, inhaled allergens, pollutants and microbes disrupt junctional complexes and promote cell death, impairing the barrier function and leading to increased penetration of pathogens and a constant airway immune response. In asthma, the inflammatory response precipitates the epithelial injury and drives abnormal basal cell differentiation. This leads to reduced ciliated cells, goblet cell hyperplasia and increased epithelial mesenchymal transition, which contribute to impaired mucociliary clearance and airway remodelling. In COPD, chronic oxidative stress and inflammation trigger premature epithelial cell senescence, which contributes to loss of epithelial integrity and airway inflammation and remodelling. Increased numbers of basal cells showing deregulated differentiation, contributes to ciliary dysfunction and mucous hyperproduction in COPD airways. Defective antioxidant, antiviral and damage repair mechanisms, possibly due to genetic or epigenetic factors, may confer susceptibility to airway epithelial dysfunction in these diseases. The current evidence suggests that a constant cycle of injury and abnormal repair of the epithelium drives chronic airway inflammation and remodelling in asthma and COPD. Mechanistic understanding of injury susceptibility and damage response may lead to improved therapies for these diseases.


Assuntos
Asma , Doença Pulmonar Obstrutiva Crônica , Transtornos Respiratórios , Humanos , Doença Pulmonar Obstrutiva Crônica/metabolismo , Pulmão/metabolismo , Inflamação
3.
Lancet Respir Med ; 11(5): 415-424, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36528039

RESUMO

BACKGROUND: COVID-19 has overwhelmed health services globally. Oral antiviral therapies are licensed worldwide, but indications and efficacy rates vary. We aimed to evaluate the safety and efficacy of oral favipiravir in patients hospitalised with COVID-19. METHODS: We conducted a multicentre, open-label, randomised controlled trial of oral favipiravir in adult patients who were newly admitted to hospital with proven or suspected COVID-19 across five sites in the UK (n=2), Brazil (n=2) and Mexico (n=1). Using a permuted block design, eligible and consenting participants were randomly assigned (1:1) to receive oral favipiravir (1800 mg twice daily for 1 day; 800 mg twice daily for 9 days) plus standard care, or standard care alone. All caregivers and patients were aware of allocation and those analysing data were aware of the treatment groups. The prespecified primary outcome was the time from randomisation to recovery, censored at 28 days, which was assessed using an intention-to-treat approach. Post-hoc analyses were used to assess the efficacy of favipiravir in patients aged younger than 60 years, and in patients aged 60 years and older. The trial was registered with clinicaltrials.gov, NCT04373733. FINDINGS: Between May 5, 2020 and May 26, 2021, we assessed 503 patients for eligibility, of whom 499 were randomly assigned to favipiravir and standard care (n=251) or standard care alone (n=248). There was no significant difference between those who received favipiravir and standard care, relative to those who received standard care alone in time to recovery in the overall study population (hazard ratio [HR] 1·06 [95% CI 0·89-1·27]; n=499; p=0·52). Post-hoc analyses showed a faster rate of recovery in patients younger than 60 years who received favipiravir and standard care versus those who had standard care alone (HR 1·35 [1·06-1·72]; n=247; p=0·01). 36 serious adverse events were observed in 27 (11%) of 251 patients administered favipiravir and standard care, and 33 events were observed in 27 (11%) of 248 patients receiving standard care alone, with infectious, respiratory, and cardiovascular events being the most numerous. There was no significant between-group difference in serious adverse events per patient (p=0·87). INTERPRETATION: Favipiravir does not improve clinical outcomes in all patients admitted to hospital with COVID-19, however, patients younger than 60 years might have a beneficial clinical response. The indiscriminate use of favipiravir globally should be cautioned, and further high-quality studies of antiviral agents, and their potential treatment combinations, are warranted in COVID-19. FUNDING: LifeArc and CW+.


Assuntos
COVID-19 , Adulto , Humanos , Pessoa de Meia-Idade , Idoso , SARS-CoV-2 , Resultado do Tratamento , Pirazinas/uso terapêutico
4.
Respiration ; 101(11): 1069-1074, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36302345

RESUMO

BACKGROUND: Targeted Lung Denervation (TLD) is a potential new therapy for COPD. Radiofrequency energy is bronchoscopically delivered to the airways to disrupt pulmonary parasympathetic nerves, to reduce bronchoconstriction, mucus hypersecretion, and bronchial hyperreactivity. OBJECTIVES: This work assesses the effect of TLD on COPD exacerbations (AECOPD) in crossover subjects in the AIRFLOW-2 trial. METHOD: The AIRFLOW-2 trial is a multicentre, randomized, double-blind, sham-controlled crossover trial of TLD in COPD. Patients with symptomatic COPD on optimal medical therapy with an FEV1 of 30-60% predicted received either TLD or sham bronchoscopy in a 1:1 randomization. Those in the sham arm had the opportunity to cross into the treatment arm after 12 months. The primary end point was rate of respiratory adverse events. Secondary end points included adverse events, changes in lung function and health-related quality of life and symptom scores. RESULTS: Twenty patients were treated with TLD in the crossover phase and were subsequently followed up for 12 months (50% female, mean age 64.1 ± 6.9 years). After TLD, there was a trend towards a reduction in time to first AECOPD (hazard ratio 0.65, p = 0.28, not statistically significant) in comparison to sham follow-up period. There was also a reduction in time to first severe AECOPD in the crossover period (hazard ratio 0.38, p = 0.227, not statistically significant). Symptom scores and lung function showed stability. CONCLUSIONS: AIRFLOW-2 crossover data support that of the randomization phase, showing trends towards reduction in COPD exacerbations with TLD.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Qualidade de Vida , Humanos , Feminino , Pessoa de Meia-Idade , Idoso , Masculino , Estudos Cross-Over , Pulmão , Denervação
6.
Immunity ; 55(3): 542-556.e5, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35151371

RESUMO

Some patients hospitalized with acute COVID-19 suffer respiratory symptoms that persist for many months. We delineated the immune-proteomic landscape in the airways and peripheral blood of healthy controls and post-COVID-19 patients 3 to 6 months after hospital discharge. Post-COVID-19 patients showed abnormal airway (but not plasma) proteomes, with an elevated concentration of proteins associated with apoptosis, tissue repair, and epithelial injury versus healthy individuals. Increased numbers of cytotoxic lymphocytes were observed in individuals with greater airway dysfunction, while increased B cell numbers and altered monocyte subsets were associated with more widespread lung abnormalities. A one-year follow-up of some post-COVID-19 patients indicated that these abnormalities resolved over time. In summary, COVID-19 causes a prolonged change to the airway immune landscape in those with persistent lung disease, with evidence of cell death and tissue repair linked to the ongoing activation of cytotoxic T cells.


Assuntos
Linfócitos B/imunologia , COVID-19/imunologia , Monócitos/imunologia , Transtornos Respiratórios/imunologia , Sistema Respiratório/imunologia , SARS-CoV-2/fisiologia , Linfócitos T Citotóxicos/imunologia , Adulto , Idoso , COVID-19/complicações , Feminino , Seguimentos , Humanos , Imunidade Celular , Imunoproteínas , Masculino , Pessoa de Meia-Idade , Proteoma , Transtornos Respiratórios/etiologia , Sistema Respiratório/patologia
7.
BMJ Open Respir Res ; 9(1)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35027428

RESUMO

INTRODUCTION: The impact of acute COVID-19 on people with asthma appears complex, being moderated by multiple interacting disease-specific, demographic and environmental factors. Research regarding longer-term effects in this group is limited. We aimed to assess impacts of COVID-19 and predictors of persistent symptoms, in people with asthma. METHODS: Using data from an online UK-wide survey of 4500 people with asthma (median age 50-59 years, 81% female), conducted in October 2020, we undertook a mixed methods analysis of the characteristics and experience of those reporting having had COVID-19. RESULTS: The COVID-19 group (n=471, 10.5%) reported increased inhaler use and worse asthma management, compared with those not reporting COVID-19, but did not differ by gender, ethnicity or household income. Among the COVID-19 group, 56.1% reported having long COVID, 20.2% were 'unsure'. Those with long COVID were more likely than those without long COVID to describe: their breathing as worse or much worse after their initial illness (73.7% vs 34.8%, p<0.001), increased inhaler use (67.8% vs 34.8%, p<0.001) and worse or much worse asthma management (59.6% vs 25.6%, p<0.001). Having long COVID was not associated with age, gender, ethnicity, UK nation or household income.Analysis of free text survey responses identified three key themes: (1) variable COVID-19 severity, duration and recovery; (2) symptom overlap and interaction between COVID-19 and asthma; (3) barriers to accessing healthcare. CONCLUSIONS: Persisting symptoms are common in people with asthma following COVID-19. Measures are needed to ensure appropriate healthcare access including clinical evaluation and investigation, to distinguish between COVID-19 symptoms and asthma.


Assuntos
Asma , COVID-19 , Asma/tratamento farmacológico , Asma/epidemiologia , COVID-19/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , SARS-CoV-2 , Reino Unido/epidemiologia , Síndrome de COVID-19 Pós-Aguda
8.
Eur Respir J ; 59(6)2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34737223

RESUMO

BACKGROUND: Proposed criteria for progressive fibrosing interstitial lung disease (PF-ILD) have been linked to increased mortality risk, but lung function trajectory after satisfying individual criteria remains unknown. Because survival is rarely employed as the primary end-point in therapeutic trials, identifying PF-ILD criteria that best predict subsequent change in forced vital capacity (FVC) could improve clinical trial design. METHODS: A retrospective, multicentre longitudinal cohort analysis was performed in consecutive patients with fibrotic connective tissue disease-associated ILD (CTD-ILD), chronic hypersensitivity pneumonitis and idiopathic interstitial pneumonia at three US centres (test cohort) and one UK centre (validation cohort). 1-year change in FVC after satisfying proposed PF-ILD criteria was estimated using joint modelling. Subgroup analyses were performed to determine whether results varied across key subgroups. RESULTS: 1227 patients were included, with CTD-ILD predominating. Six out of nine PF-ILD criteria were associated with differential 1-year change in FVC, with radiological progression of fibrosis, alone and in combination with other features, associated with the largest subsequent decline in FVC. Findings varied significantly by ILD subtype, with CTD-ILD demonstrating little change in FVC after satisfying most PF-ILD criteria, while other ILDs showed significantly larger changes. Findings did not vary after stratification by radiological pattern or exposure to immunosuppressant therapy. Near-term change in FVC after satisfying proposed PF-ILD criteria was heterogeneous depending on the criterion assessed and was strongly influenced by ILD subtype. CONCLUSIONS: These findings may inform future clinical trial design and suggest ILD subtype should be taken into consideration when applying PF-ILD criteria.


Assuntos
Pneumonias Intersticiais Idiopáticas , Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Progressão da Doença , Fibrose , Humanos , Pneumonias Intersticiais Idiopáticas/complicações , Fibrose Pulmonar Idiopática/complicações , Estudos Longitudinais , Pulmão , Doenças Pulmonares Intersticiais/etiologia , Estudos Retrospectivos , Capacidade Vital
9.
Radiology ; 303(2): 444-454, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609195

RESUMO

Background Data on the long-term pulmonary sequelae in COVID-19 are lacking. Purpose To assess symptoms, functional impairment, and residual pulmonary abnormalities on serial chest CT scans in COVID-19 survivors discharged from hospital at up to 1-year follow-up. Materials and Methods Adult patients with COVID-19 discharged between March 2020 and June 2020 were prospectively evaluated at 3 months and 1 year through systematic assessment of symptoms, functional impairment, and thoracic CT scans as part of the PHENOTYPE study, an observational cohort study in COVID-19 survivors. Lung function testing was limited to participants with CT abnormalities and/or persistent breathlessness. Bonferroni correction was used. Results Eighty participants (mean age, 59 years ± 13 [SD]; 53 men) were assessed. At outpatient review, persistent breathlessness was reported in 37 of the 80 participants (46%) and cough was reported in 17 (21%). CT scans in 73 participants after discharge (median, 105 days; IQR, 95-141 days) revealed persistent abnormalities in 41 participants (56%), with ground-glass opacification (35 of 73 participants [48%]) and bands (27 of 73 participants [37%]) predominating. Unequivocal signs indicative of established fibrosis (ie, volume loss and/or traction bronchiectasis) were present in nine of 73 participants (12%). Higher admission serum C-reactive protein (in milligrams per liter), fibrinogen (in grams per deciliter), urea (millimoles per liter), and creatinine (micromoles per liter) levels; longer hospital stay (in days); older age (in years); and requirement for invasive ventilation were associated with CT abnormalities at 3-month follow-up. Thirty-two of 41 participants (78%) with abnormal findings at 3-month follow-up CT underwent repeat imaging at a median of 364 days (range, 360-366 days), with 26 (81%) showing further radiologic improvement (median, 18%; IQR, 10%-40%). Conclusion CT abnormalities were common at 3 months after COVID-19 but with signs of fibrosis in a minority. More severe acute disease was linked with CT abnormalities at 3 months. However, radiologic improvement was seen in the majority at 1-year follow-up. ClinicalTrials.gov identifier: NCT04459351. © RSNA, 2022 Online supplemental material is available for this article.


Assuntos
COVID-19 , Alta do Paciente , COVID-19/diagnóstico por imagem , Dispneia , Fibrose , Hospitais , Humanos , Pulmão/diagnóstico por imagem , Tomografia Computadorizada por Raios X
11.
Arch Toxicol ; 95(1): 321-336, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32910239

RESUMO

Current in vitro genotoxicity tests can produce misleading positive results, indicating an inability to effectively predict a compound's subsequent carcinogenic potential in vivo. Such oversensitivity can incur unnecessary in vivo tests to further investigate positive in vitro results, supporting the need to improve in vitro tests to better inform risk assessment. It is increasingly acknowledged that more informative in vitro tests using multiple endpoints may support the correct identification of carcinogenic potential. The present study, therefore, employed a holistic, multiple-endpoint approach using low doses of selected carcinogens and non-carcinogens (0.001-770 µM) to assess whether these chemicals caused perturbations in molecular and cellular endpoints relating to the Hallmarks of Cancer. Endpoints included micronucleus induction, alterations in gene expression, cell cycle dynamics, cell morphology and bioenergetics in the human lymphoblastoid cell line TK6. Carcinogens ochratoxin A and oestradiol produced greater Integrated Signature of Carcinogenicity scores for the combined endpoints than the "misleading" in vitro positive compounds, quercetin, 2,4-dichlorophenol and quinacrine dihydrochloride and toxic non-carcinogens, caffeine, cycloheximide and phenformin HCl. This study provides compelling evidence that carcinogens can successfully be distinguished from non-carcinogens using a holistic in vitro test system. Avoidance of misleading in vitro outcomes could lead to the reduction and replacement of animals in carcinogenicity testing.


Assuntos
Testes de Carcinogenicidade , Carcinógenos/toxicidade , Determinação de Ponto Final , Projetos de Pesquisa , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Forma Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos , Fosforilação , Medição de Risco , Proteína Supressora de Tumor p53/metabolismo
12.
Mutagenesis ; 35(6): 445-452, 2020 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-33219664

RESUMO

In vitro genotoxicity studies are a quick and high throughput approach to assess the genotoxic potential of chemicals; however, the reliability of these tests and their relevance to in vivo effects depends on the choice of representative cell line and optimisation of assay conditions. For chemicals like urethane that require specific metabolic activation to cause genotoxicity, it is important that in vitro tests are conducted using cell lines exhibiting the activity and induction of CYP450 enzymes, including CYP2E1 enzyme that is important in the metabolism of urethane, at a concentration representing actual or perceived chemical exposure. We compared 2D MCL-5 cells and HepG2 cells with 3D HepG2 hanging drop spheroids to determine the genotoxicity of urethane using the micronucleus assay. Our 2D studies with MCL-5 did not show any statistically significant genotoxicity [99% relative population doubling (RPD)] compared to controls for concentrations and time point tested in vitro. HepG2 cells grown as 2D indicated that exposure to urethane of up to 30 mM for 23 h did not cause any genotoxic effect (102% RPD) but, at higher concentrations, genotoxicity was produced with only 89-85% RPD. Furthermore, an exposure of 20-50 mM for 23 h using 3D hanging drop spheroid assays revealed a higher MN frequency, thus exhibiting in vitro genotoxicity of urethane in metabolically active cell models. In comparison with previous studies, this study indicated that urethane genotoxicity is dose, sensitivity of cell model (2D vs. 3D) and exposure dependent.


Assuntos
Testes de Mutagenicidade/métodos , Mutagênicos/toxicidade , Uretana/toxicidade , Biomarcadores , Técnicas de Cultura de Células , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Respiração Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Humanos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos/métodos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Esferoides Celulares
13.
Arch Toxicol ; 92(2): 935-951, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29110037

RESUMO

Human exposure to carcinogens occurs via a plethora of environmental sources, with 70-90% of cancers caused by extrinsic factors. Aberrant phenotypes induced by such carcinogenic agents may provide universal biomarkers for cancer causation. Both current in vitro genotoxicity tests and the animal-testing paradigm in human cancer risk assessment fail to accurately represent and predict whether a chemical causes human carcinogenesis. The study aimed to establish whether the integrated analysis of multiple cellular endpoints related to the Hallmarks of Cancer could advance in vitro carcinogenicity assessment. Human lymphoblastoid cells (TK6, MCL-5) were treated for either 4 or 23 h with 8 known in vivo carcinogens, with doses up to 50% Relative Population Doubling (maximum 66.6 mM). The adverse effects of carcinogens on wide-ranging aspects of cellular health were quantified using several approaches; these included chromosome damage, cell signalling, cell morphology, cell-cycle dynamics and bioenergetic perturbations. Cell morphology and gene expression alterations proved particularly sensitive for environmental carcinogen identification. Composite scores for the carcinogens' adverse effects revealed that this approach could identify both DNA-reactive and non-DNA reactive carcinogens in vitro. The richer datasets generated proved that the holistic evaluation of integrated phenotypic alterations is valuable for effective in vitro risk assessment, while also supporting animal test replacement. Crucially, the study offers valuable insights into the mechanisms of human carcinogenesis resulting from exposure to chemicals that humans are likely to encounter in their environment. Such an understanding of cancer induction via environmental agents is essential for cancer prevention.


Assuntos
Testes de Carcinogenicidade/métodos , Carcinógenos/toxicidade , Linfócitos/efeitos dos fármacos , Mutagênicos/toxicidade , Linhagem Celular , Humanos , Testes para Micronúcleos , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , Proteína Supressora de Tumor p53/metabolismo
14.
Nat Methods ; 11(11): 1177-81, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25218182

RESUMO

For phenotypic behavior to be understood in the context of cell lineage and local environment, properties of individual cells must be measured relative to population-wide traits. However, the inability to accurately identify, track and measure thousands of single cells via high-throughput microscopy has impeded dynamic studies of cell populations. We demonstrate unique labeling of cells, driven by the heterogeneous random uptake of fluorescent nanoparticles of different emission colors. By sequentially exposing a cell population to different particles, we generated a large number of unique digital codes, which corresponded to the cell-specific number of nanoparticle-loaded vesicles and were visible within a given fluorescence channel. When three colors are used, the assay can self-generate over 17,000 individual codes identifiable using a typical fluorescence microscope. The color-codes provided immediate visualization of cell identity and allowed us to track human cells with a success rate of 78% across image frames separated by 8 h.


Assuntos
Rastreamento de Células/métodos , Corantes Fluorescentes , Pontos Quânticos , Linhagem Celular , Humanos , Microscopia de Fluorescência
15.
ACS Nano ; 7(7): 6129-37, 2013 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-23773085

RESUMO

Assessing dose in nanoparticle-cell interactions is inherently difficult due to a complex multiplicity of possible mechanisms and metrics controlling particle uptake. The fundamental unit of nanoparticle dose is the number of particles internalized per cell; we show that this can be obtained for large cell populations that internalize fluorescent nanoparticles by endocytosis, through calibration of cytometry measurements to transmission electron microscopy data. Low-throughput, high-resolution electron imaging of quantum dots in U-2 OS cells is quantified and correlated with high-throughput, low-resolution optical imaging of the nanoparticle-loaded cells. From the correlated data, we obtain probability distribution functions of vesicles per cell and nanoparticles per vesicle. Sampling of these distributions and comparison to fluorescence intensity histograms from flow cytometry provide the calibration factor required to transform the cytometry metric to total particle dose per cell, the mean value of which is 2.4 million. Use of the probability distribution functions to analyze particle partitioning during cell division indicates that, while vesicle inheritance is near symmetric, highly variable vesicle loading leads to a highly asymmetric particle dose within the daughter cells.


Assuntos
Interpretação Estatística de Dados , Endocitose/fisiologia , Citometria de Fluxo/métodos , Microscopia de Fluorescência/métodos , Nanopartículas/análise , Nanopartículas/química , Vesículas Transportadoras/química , Proliferação de Células
16.
PLoS One ; 7(7): e40835, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22829889

RESUMO

An automated technique for the identification, tracking and analysis of biological cells is presented. It is based on the use of nanoparticles, enclosed within intra-cellular vesicles, to produce clusters of discrete, point-like fluorescent, light sources within the cells. Computational analysis of these light ensembles in successive time frames of a movie sequence, using k-means clustering and particle tracking algorithms, provides robust and automated discrimination of live cells and their motion and a quantitative measure of their proliferation. This approach is a cytometric version of the moving light display technique which is widely used for analyzing the biological motion of humans and animals. We use the endocytosis of CdTe/ZnS, core-shell quantum dots to produce the light displays within an A549, epithelial, lung cancer cell line, using time-lapse imaging with frame acquisition every 5 minutes over a 40 hour time period. The nanoparticle moving light displays provide simultaneous collection of cell motility data, resolution of mitotic traversal dynamics and identification of familial relationships allowing construction of multi-parameter lineage trees.


Assuntos
Nanopartículas/química , Nanotecnologia/métodos , Compostos de Cádmio/química , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Modelos Teóricos , Pontos Quânticos , Sulfetos/química , Telúrio/química , Compostos de Zinco/química
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