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1.
Blood ; 137(4): 500-512, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33507291

RESUMO

Glucocorticoid (GC) resistance remains a clinical challenge in pediatric acute lymphoblastic leukemia where response to GC is a reliable prognostic indicator. To identify GC resistance pathways, we conducted a genome-wide, survival-based, short hairpin RNA screen in murine T-cell acute lymphoblastic leukemia (T-ALL) cells. Genes identified in the screen interfere with cyclic adenosine monophosphate (cAMP) signaling and are underexpressed in GC-resistant or relapsed ALL patients. Silencing of the cAMP-activating Gnas gene interfered with GC-induced gene expression, resulting in dexamethasone resistance in vitro and in vivo. We demonstrate that cAMP signaling synergizes with dexamethasone to enhance cell death in GC-resistant human T-ALL cells. We find the E prostanoid receptor 4 expressed in T-ALL samples and demonstrate that prostaglandin E2 (PGE2) increases intracellular cAMP, potentiates GC-induced gene expression, and sensitizes human T-ALL samples to dexamethasone in vitro and in vivo. These findings identify PGE2 as a target for GC resensitization in relapsed pediatric T-ALL.


Assuntos
AMP Cíclico/fisiologia , Dexametasona/farmacologia , Dinoprostona/farmacologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Sistemas do Segundo Mensageiro/efeitos dos fármacos , 1-Metil-3-Isobutilxantina/farmacologia , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linhagem Celular Tumoral , Criança , Cromograninas/antagonistas & inibidores , Colforsina/farmacologia , AMP Cíclico/farmacologia , Dexametasona/administração & dosagem , Dinoprostona/administração & dosagem , Dinoprostona/antagonistas & inibidores , Dinoprostona/fisiologia , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/fisiologia , Feminino , Subunidades alfa Gs de Proteínas de Ligação ao GTP/antagonistas & inibidores , Subunidades alfa Gs de Proteínas de Ligação ao GTP/deficiência , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Camundongos , Modelos Animais , Terapia de Alvo Molecular , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/farmacologia , Quimera por Radiação , Receptores de Glucocorticoides/biossíntese , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/fisiologia , Receptores de Prostaglandina E Subtipo EP4/biossíntese , Receptores de Prostaglandina E Subtipo EP4/genética , Ensaios Antitumorais Modelo de Xenoenxerto
2.
Prev Med ; 140: 106201, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32652133

RESUMO

Cigarette smoking during pregnancy increases risk for pregnancy complications, growth restriction, and other adverse health outcomes. The most effective intervention for reducing smoking during pregnancy is financial incentives contingent on biochemically-verified smoking abstinence. The present study examined the efficacy of a smartphone-based intervention whereby smoking monitoring and incentive delivery occurred remotely using a mobile app. If efficacious, this remote intervention would allow pregnant women residing in geographically remote areas to benefit from incentives-based cessation interventions. Sixty U.S. pregnant smokers were recruited between May 2018 to May 2019 via obstetrical clinics, Women, Infants, and Children (WIC) offices, and Facebook. Participants were assigned sequentially to one of two treatments: best practices alone (N = 30) or best practices plus financial incentives (N = 30). Outcomes were analyzed using repeated measures analysis based on generalized estimating equations (GEE). Seven-day point prevalence abstinence rates were greater in the incentives versus best practices arms early- (46.7% vs 20.0%, OR = 3.50, 95%CI = 1.11,11.02) and late-antepartum (36.7% vs 13.3%, OR = 3.76, 95%CI = 1.04,13.65), and four- (36.7% vs 10.0%, OR = 5.21, 95%CI = 1.28,21.24) and eight-weeks postpartum (40.0% vs 6.7%, OR = 9.33, 95%CI = 1.87,46.68), although not at the 12- (23.3% vs 10.0%, OR = 2.74, 95%CI = 0.63,11.82) or 24-week (20.0% vs 6.7%, OR = 3.50, 95%CI = 0.65,18.98) postpartum assessments likely due to this pilot study being underpowered for discerning differences at the later assessments, especially 24-weeks postpartum which was three months after treatment completion. These results support the efficacy of this remote, incentives-based intervention for pregnant smokers. Further research evaluating its efficacy and cost-effectiveness in a well-powered, randomized controlled trial appears warranted.


Assuntos
Motivação , Abandono do Hábito de Fumar , Criança , Feminino , Humanos , Projetos Piloto , Gravidez , Gestantes , Smartphone
3.
Prev Med ; 118: 238-242, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30412743

RESUMO

Women of reproductive age and particularly pregnant women underutilize evidence-based smoking cessation services such as counseling and quit lines. Mobile health (mHealth) may constitute an unexplored and innovative avenue for providing smoking cessation support to a population that is otherwise difficult to reach with evidence-based interventions. Female respondents aged 18-44 years (N = 10,023) were drawn from the first wave of the Population Assessment of Tobacco and Health (PATH) study (2013-2014). We examined prevalence of use of various digital forms of communication (e.g., social media, text messaging, smartphone ownership) among non-pregnant women of reproductive age, pregnant women, and among smokers versus non-smokers within these groups. Multiple logistic regression modeling was conducted to identify correlates of using each digital form adjusting for smoking status, pregnancy, and demographic characteristics. Over two thirds of women overall and within subgroups of non-pregnant and pregnant smokers reported using social media, owning a cell phone, owning a smartphone, downloading apps, and sending/receiving text messages. Current smokers and those with lower educational attainment generally had lower odds of using each digital form relative to non-smokers and those with higher educational attainment, the exception being that smokers had higher odds of using social media relative to non-smokers. The high prevalence of using various digital forms among both non-pregnant smokers of reproductive age and pregnant smokers suggests that leveraging technology to expand access to prevention, education, and treatment resources may reduce smoking-attributable adverse health effects among reproductive-aged women and their offspring.


Assuntos
Fumar Cigarros/efeitos adversos , Fumar Cigarros/epidemiologia , Fumantes/estatística & dados numéricos , Telemedicina , Adulto , Aconselhamento , Feminino , Humanos , Gravidez , Prevalência , Smartphone/estatística & dados numéricos , Abandono do Hábito de Fumar/psicologia , Mídias Sociais/estatística & dados numéricos , Envio de Mensagens de Texto/estatística & dados numéricos , Estados Unidos/epidemiologia , Adulto Jovem
4.
Nat Mater ; 16(6): 671-680, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28319612

RESUMO

Host recognition and immune-mediated foreign body response to biomaterials can compromise the performance of implanted medical devices. To identify key cell and cytokine targets, here we perform in-depth systems analysis of innate and adaptive immune system responses to implanted biomaterials in rodents and non-human primates. While macrophages are indispensable to the fibrotic cascade, surprisingly neutrophils and complement are not. Macrophages, via CXCL13, lead to downstream B cell recruitment, which further potentiated fibrosis, as confirmed by B cell knockout and CXCL13 neutralization. Interestingly, colony stimulating factor-1 receptor (CSF1R) is significantly increased following implantation of multiple biomaterial classes: ceramic, polymer and hydrogel. Its inhibition, like macrophage depletion, leads to complete loss of fibrosis, but spares other macrophage functions such as wound healing, reactive oxygen species production and phagocytosis. Our results indicate that targeting CSF1R may allow for a more selective method of fibrosis inhibition, and improve biomaterial biocompatibility without the need for broad immunosuppression.


Assuntos
Materiais Biocompatíveis/efeitos adversos , Reação a Corpo Estranho/induzido quimicamente , Reação a Corpo Estranho/metabolismo , Próteses e Implantes/efeitos adversos , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Animais , Reação a Corpo Estranho/imunologia , Camundongos , Primatas
5.
Prev Med ; 117: 52-60, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30145348

RESUMO

This study examined quit rates longitudinally for cigarettes, e-cigarettes, hookah, cigars, and all tobacco products in a U.S. national sample of women aged 18-44 who completed both Wave 1 (W1) and Wave 2 (W2) of the Population Assessment of Tobacco and Health (PATH, 2013-2014, 2014-2015) study (N = 7814). Quit rates were examined among women who transitioned into pregnancy across survey waves, and among a comparable sample of non-pregnant women to provide contextual information about quitting among the broader population of reproductive-aged women. Multiple logistic regression modeling was used to estimate the associations of pregnancy and quitting adjusting for other demographic and psychosocial characteristics. Quit rates among women who were pregnant in W2 were highest for hookah (98.3%), followed by cigars (88.0%), e-cigarettes (81.3%), and lowest for tobacco cigarettes (53.4%). Slightly more than half (58.7%) of women reported quitting use all tobacco products while pregnant. Pregnancy was independently associated with increased odds of quitting hookah (AOR = 52.9, 95%CI = 3.4, 830.2), e-cigarettes (AOR = 21.0, 95%CI = 2.6, 170.3), all tobacco products (AOR = 9.6, 95%CI = 6.4, 14.5), and cigarettes (AOR = 6.5, 95%CI = 4.2, 10.1), although not cigars. Relative to other demographic and psychosocial characteristics, pregnancy was the strongest predictor of quitting use of each tobacco product. While these data indicate that pregnancy has strong, independent associations with quitting a variety of commercially available tobacco products, the comparatively lower quit rates for cigarettes versus other tobacco products underscores the long-standing need for more intensive, multipronged clinical and regulatory interventions to reduce cigarette use among reproductive-aged women.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Produtos do Tabaco/estatística & dados numéricos , Abandono do Uso de Tabaco/estatística & dados numéricos , Adolescente , Adulto , Fumar Cigarros , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Gravidez , Inquéritos e Questionários , Produtos do Tabaco/efeitos adversos , Estados Unidos , Adulto Jovem
7.
Nat Mater ; 14(6): 643-51, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25985456

RESUMO

The efficacy of implanted biomedical devices is often compromised by host recognition and subsequent foreign body responses. Here, we demonstrate the role of the geometry of implanted materials on their biocompatibility in vivo. In rodent and non-human primate animal models, implanted spheres 1.5 mm and above in diameter across a broad spectrum of materials, including hydrogels, ceramics, metals and plastics, significantly abrogated foreign body reactions and fibrosis when compared with smaller spheres. We also show that for encapsulated rat pancreatic islet cells transplanted into streptozotocin-treated diabetic C57BL/6 mice, islets prepared in 1.5-mm alginate capsules were able to restore blood-glucose control for up to 180 days, a period more than five times longer than for transplanted grafts encapsulated within conventionally sized 0.5-mm alginate capsules. Our findings suggest that the in vivo biocompatibility of biomedical devices can be significantly improved simply by tuning their spherical dimensions.


Assuntos
Reação a Corpo Estranho/imunologia , Animais , Camundongos , Camundongos Endogâmicos C57BL , Primatas
8.
Hosp Pediatr ; 14(4): 281-290, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38482585

RESUMO

OBJECTIVES: Antimicrobial stewardship programs (ASPs) restrict prescribing practices to regulate antimicrobial use, increasing the risk of prescribing errors. This quality improvement project aimed to decrease the proportion of prescribing errors in ASP-restricted medications by standardizing workflow. METHODS: The study took place on all inpatient units at a tertiary care children's hospital between January 2020 and February 2022. Patients <22 years old with an order for an ASP-restricted medication course were included. An interprofessional team used the Model for Improvement to design interventions targeted at reducing ASP-restricted medication prescribing errors. Plan-Do-Study-Act cycles included standardizing communication and medication review, implementing protocols, and developing electronic health record safety nets. The primary outcome was the proportion of ASP-restricted medication orders with a prescribing error. The secondary outcome was time between prescribing errors. Outcomes were plotted on control charts and analyzed for special cause variation. Outcomes were monitored for a 3-month sustainability period. RESULTS: Nine-hundred ASP-restricted medication orders were included in the baseline period (January 2020-December 2020) and 1035 orders were included in the intervention period (January 2021-February 2022). The proportion of prescribing errors decreased from 10.9% to 4.6%, and special cause variation was observed in Feb 2021. Mean time between prescribing errors increased from 2.9 days to 8.5 days. These outcomes were sustained. CONCLUSIONS: Quality improvement methods can be used to achieve a sustained reduction in the proportion of ASP-restricted medication orders with a prescribing error throughout an entire children's hospital.


Assuntos
Anti-Infecciosos , Gestão de Antimicrobianos , Criança , Humanos , Adulto Jovem , Adulto , Erros de Medicação/prevenção & controle , Anti-Infecciosos/uso terapêutico , Prescrições de Medicamentos , Registros Eletrônicos de Saúde
9.
Pediatr Pulmonol ; 58(6): 1738-1745, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37014143

RESUMO

INTRODUCTION: Both respiratory syncytial virus (RSV) and influenza-associated lower respiratory tract infections (LRTI) cause serious respiratory infections in infants and toddlers. We aimed to assess the frequency of complex hospital courses among patients admitted with influenza versus RSV LRTI. METHODS: A retrospective cohort study was performed on admissions of children <2 years who were admitted for LRTI and tested positive for influenza or RSV from 2016 to 2019. The primary outcome, complex hospital course, was a composite including: intensive care unit admission, respiratory support, nasogastric tube feeds, prolonged length of stay, and death. Secondary outcomes included 7-day readmission and time to respiratory support. Differences between RSV and influenza groups were assessed and unadjusted and adjusted regression models and competing risks time to event models were developed. RESULTS: There were 1094 (89%) RSV admissions and 134 (11%) influenza admissions. Children admitted for influenza were significantly older (336 vs. 165 days, p < 0.001), more likely to present with an abnormal heart rate for age (84.3% vs. 73.5%, p < 0.01) and a fever (27.6% vs. 18.9%, p = 0.02). Admissions with RSV were significantly more likely to experience a complex hospital course (ORadj = 3.5, 95% CI: 2.2-5.6). In time to event analysis, RSV admissions had a significantly higher rate of respiratory support (HRadj = 3.2, 95% CI: 2.0, 5.2). Readmission rates were similar. CONCLUSIONS: RSV admissions were associated with a higher risk for a complex hospital course and required higher rates of respiratory support than influenza admissions. This information may help in evaluating hospital resources and admissions.


Assuntos
Influenza Humana , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Infecções Respiratórias , Lactente , Humanos , Pré-Escolar , Influenza Humana/complicações , Influenza Humana/epidemiologia , Estudos Retrospectivos , Hospitalização , Infecções por Vírus Respiratório Sincicial/complicações , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções Respiratórias/complicações
10.
Exp Clin Psychopharmacol ; 29(4): 366-374, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33180541

RESUMO

Data indicate household-smoking bans aid cessation and reduce secondhand smoke exposure. This study assessed prevalence of antepartum (AP) and postpartum (PP) household-smoking bans and associations with nicotine exposure, abstinence, and birth weight among pregnant women. The current study is a secondary analysis of clinical trials examining the efficacy of financial incentives for smoking-cessation among pregnant women (N = 284). Participants were current smokers at the start of prenatal care and followed from ∼10 weeks gestational age through 24 weeks PP. Household-smoking rules and biochemically verified urinary cotinine were measured repeatedly. Nicotine exposure and birth weight were analyzed using analysis of covariance. Association with abstinence was analyzed using backward elimination logistic regressions. Prevalence of household-smoking bans increased from ∼ 45% to 55% AP and then increased to ∼80% PP. Women with a ban exhibited lower nicotine exposure in early and late pregnancy compared to smokers without a ban. Women with a ban at baseline or who adopted a ban early in treatment were more likely to be abstinent at late pregnancy and 24 weeks PP compared to women without a ban. There was a dose-response relationship between combined exposure (i.e., smoking and ban status) and infant birth weight, with infants of women who quit and reported a ban having the highest adjusted mean birth weight (3426 ± 63 g), while infants of women who continued smoking without a ban having the lowest (3153 ± 37 g). These results provide an empirical rationale for prospectively investigating whether adopting a household-smoking ban can reduce fetal exposure among pregnant smokers. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Nicotina , Gestantes , Política Antifumo , Abandono do Hábito de Fumar , Feminino , Humanos , Gravidez , Fumar
11.
Exp Clin Psychopharmacol ; 28(6): 706-713, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32105135

RESUMO

The Cigarette Purchase Task (CPT), in which participants estimate the number of cigarettes they would smoke across increasing cigarette prices, measures the relative reinforcing value of cigarettes. Although opioid-dependent individuals are particularly vulnerable to tobacco addiction, more research is needed to elucidate whether and to what extent their motivation to smoke differs from not-opioid-dependent smokers controlling for potential sociodemographic differences. Participants were 173 women (65 opioid-dependent) in an ongoing clinical trial for smoking cessation. Baseline CPT responses were compared between opioid-dependent and not-opioid-dependent women using five demand indices: Demand Intensity; Omax; Pmax; Breakpoint (BP); and α, and two latent factors: Amplitude and Persistence. Final regression models adjusted for sociodemographic characteristics differing between the two groups. Opioid-dependent women had greater demand Intensity (i.e., number of cigarettes they would smoke if they were free) than not-opioid dependent women in the adjusted model, F(1, 156) = 6.93, p = .016. No other demand indices differed significantly. Regarding latent factors, demand Amplitude (i.e., volumetric consumption), but not Persistence (i.e., price insensitivity), was greater for opioid-dependent women in the adjusted model, F(1, 146) = 4.04, p = .046. These results further demonstrate that the CPT is a highly sensitive task that can illuminate potentially important individual and population differences in the relative reinforcing value of smoking. Greater demand Intensity and Amplitude differentiated smokers with comorbid opioid dependence; thus, decreasing smoking prevalence among opioid-dependent populations may require policies and interventions that can decrease cigarette demand Intensity and Amplitude. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Assuntos
Mães , Transtornos Relacionados ao Uso de Opioides , Reforço Psicológico , Produtos do Tabaco , Fumar Tabaco , Adulto , Comportamento Aditivo , Estudos de Casos e Controles , Feminino , Humanos
12.
Drug Alcohol Depend ; 207: 107801, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31855658

RESUMO

BACKGROUND: Identifying predictors of tobacco use patterns that differ in harm among reproductive-aged women may inform efforts to protect women and children against adverse health impacts of tobacco use. METHODS: Changes in tobacco use patterns were examined among women (18-49 years) who completed Wave 1 (W1) and Wave 2 (W2), or W2 and Wave 3 (W3) of the U.S. Population Assessment of Tobacco and Health (PATH, 2013-2016) study, and were using cigarettes, filtered cigars and/or cigarillos in the first wave over which data were included for that respondent (Time 1; T1). We examined the proportion of respondents whose tobacco use transitions from T1 to Time 2 (T2) were harm-maintaining (continued using combusted tobacco), harm-reducing (transitioned to electronic nicotine delivery systems (ENDS), or harm-eliminating (quit tobacco). Multinomial logistic regressions (with harm-maintaining as the baseline category) were conducted to examine associations between ENDS use, demographic, and psychosocial characteristics with each transition. RESULTS: A majority of women (83 %) exhibited harm-maintaining transitions, followed by harm-eliminating (14.7 %) and harm-reducing (2.3 %) transitions. Use of ENDS at T1 was associated with increased odds of harm reduction and decreased odds of harm elimination. Younger women were more likely to make both harm-reducing and harm-eliminating transitions. Increased educational attainment, identifying as Black or Hispanic, increased psychiatric symptoms, and pregnancy were associated with harm elimination, whereas living at or above poverty was associated with harm reduction. CONCLUSIONS: Study results contribute new information on the impact of ENDS, sociodemographic characteristics, psychiatric symptoms, and pregnancy on tobacco use transitions among reproductive-aged women.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Abandono do Hábito de Fumar/estatística & dados numéricos , Uso de Tabaco/epidemiologia , Adolescente , Adulto , Feminino , Redução do Dano , Humanos , Pessoa de Meia-Idade , Fatores de Risco , Inquéritos e Questionários , Estados Unidos/epidemiologia , Adulto Jovem
13.
Hum Mutat ; 30(12): 1683-92, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19862843

RESUMO

Pompe disease is a lysosomal storage disorder (LSD) caused by mutations in the gene that encodes acid alpha-glucosidase (GAA). Recently, small molecule pharmacological chaperones have been shown to increase protein stability and cellular levels for mutant lysosomal enzymes and have emerged as a new therapeutic strategy for the treatment of LSDs. In this study, we characterized the pharmacological chaperone 1-deoxynojirimycin (DNJ) on 76 different mutant forms of GAA identified in Pompe disease. DNJ significantly increased enzyme activity and protein levels for 16 different GAA mutants in patient-derived fibroblasts and in transiently transfected COS-7 cells. Additionally, DNJ increased the processing of these GAA mutants to their mature lysosomal forms, suggesting facilitated trafficking through the secretory pathway. Immunofluorescence microscopy studies showed increased colocalization of GAA with the lysosomal marker LAMP2 after incubation with DNJ, confirming increased lysosomal trafficking. Lastly, a GAA structural model was constructed based on the related eukaryotic glucosidase maltase-glucoamylase. The mutated residues identified in responsive forms of GAA are located throughout most of the structural domains, with half of these residues located in two short regions within the catalytic domain. Taken together, these data support further evaluation of DNJ as a potential treatment for Pompe disease in patients that express responsive forms of GAA.


Assuntos
1-Desoxinojirimicina/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/enzimologia , Proteínas Mutantes/metabolismo , alfa-Glucosidases/metabolismo , Adolescente , Adulto , Animais , Células COS , Chlorocebus aethiops , Estabilidade Enzimática/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Doença de Depósito de Glicogênio Tipo II/enzimologia , Humanos , Lactente , Modelos Moleculares , Estrutura Secundária de Proteína , Transporte Proteico/efeitos dos fármacos , Proteínas Recombinantes/metabolismo , alfa-Glucosidases/química
14.
Med Phys ; 36(11): 4944-56, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19994503

RESUMO

PURPOSE: MANTIS is a Monte Carlo code developed for the detailed simulation of columnar CsI scintillator screens in x-ray imaging systems. Validation of this code is needed to provide a reliable and valuable tool for system optimization and accurate reconstructions for a variety of x-ray applications. Whereas previous validation efforts have focused on matching of summary statistics, in this work the authors examine the complete point response function (PRF) of the detector system in addition to relative light output values. METHODS: Relative light output values and high-resolution PRFs have been experimentally measured with a custom setup. A corresponding set of simulated light output values and PRFs have also been produced, where detailed knowledge of the experimental setup and CsI:Tl screen structures are accounted for in the simulations. Four different screens were investigated with different thicknesses, column tilt angles, and substrate types. A quantitative comparison between the experimental and simulated PRFs was performed for four different incidence angles (0 degrees, 15 degrees, 30 degrees, and 45 degrees) and two different x-ray spectra (40 and 70 kVp). The figure of merit (FOM) used measures the normalized differences between the simulated and experimental data averaged over a region of interest. RESULTS: Experimental relative light output values ranged from 1.456 to 1.650 and were in approximate agreement for aluminum substrates, but poor agreement for graphite substrates. The FOMs for all screen types, incidence angles, and energies ranged from 0.1929 to 0.4775. To put these FOMs in context, the same FOM was computed for 2D symmetric Gaussians fit to the same experimental data. These FOMs ranged from 0.2068 to 0.8029. Our analysis demonstrates that MANTIS reproduces experimental PRFs with higher accuracy than a symmetric 2D Gaussian fit to the experimental data in the majority of cases. Examination of the spatial distribution of differences between the PRFs shows that the main reason for errors between MANTIS and the experimental data is that MANTIS-generated PRFs are sharper than the experimental PRFs. CONCLUSIONS: The experimental validation of MANTIS performed in this study demonstrates that MANTIS is able to reliably predict experimental PRFs, especially for thinner screens, and can reproduce the highly asymmetric shape seen in the experimental data. As a result, optimizations and reconstructions carried out using MANTIS should yield results indicative of actual detector performance. Better characterization of screen properties is necessary to reconcile the simulated light output values with experimental data.


Assuntos
Césio , Simulação por Computador , Iodetos , Método de Monte Carlo , Intensificação de Imagem Radiográfica , Validação de Programas de Computador , Raios X , Alumínio , Grafite , Humanos , Luz , Distribuição Normal , Intensificação de Imagem Radiográfica/instrumentação , Intensificação de Imagem Radiográfica/métodos
16.
J Leukoc Biol ; 100(2): 253-60, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26965635

RESUMO

Neutrophils are constantly generated from hematopoietic stem and progenitor cells in the bone marrow to maintain high numbers in circulation. A considerable number of neutrophils and their progenitors have been shown to be present in the spleen too; however, their exact role in this organ remains unclear. Herein, we sought to study the function of splenic neutrophils and their progenitors using a mouse model for sterile, peritoneal inflammation. In this microcapsule device implantation model, we show chronic neutrophil presence at implant sites, with recruitment from circulation as the primary mechanism for their prevalence in the peritoneal exudate. Furthermore, we demonstrate that progenitor populations in the spleen play a key role in maintaining elevated neutrophil numbers. Our results provide new insight into the role for splenic neutrophils and their progenitors and establish a model to study neutrophil function during sterile inflammation.


Assuntos
Medula Óssea/imunologia , Inflamação/imunologia , Infiltração de Neutrófilos/imunologia , Neutrófilos/imunologia , Baço/imunologia , Células-Tronco/imunologia , Animais , Medula Óssea/metabolismo , Medula Óssea/patologia , Doença Crônica , Citocinas/metabolismo , Feminino , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/citologia , Neutrófilos/metabolismo , Fagocitose , Próteses e Implantes/efeitos adversos , Baço/patologia , Células-Tronco/citologia , Células-Tronco/metabolismo
17.
Nat Biotechnol ; 34(3): 345-52, 2016 03.
Artigo em Inglês | MEDLINE | ID: mdl-26807527

RESUMO

The foreign body response is an immune-mediated reaction that can lead to the failure of implanted medical devices and discomfort for the recipient. There is a critical need for biomaterials that overcome this key challenge in the development of medical devices. Here we use a combinatorial approach for covalent chemical modification to generate a large library of variants of one of the most widely used hydrogel biomaterials, alginate. We evaluated the materials in vivo and identified three triazole-containing analogs that substantially reduce foreign body reactions in both rodents and, for at least 6 months, in non-human primates. The distribution of the triazole modification creates a unique hydrogel surface that inhibits recognition by macrophages and fibrous deposition. In addition to the utility of the compounds reported here, our approach may enable the discovery of other materials that mitigate the foreign body response.


Assuntos
Corpos Estranhos/imunologia , Reação a Corpo Estranho/imunologia , Hidrogéis/uso terapêutico , Próteses e Implantes/efeitos adversos , Animais , Materiais Biocompatíveis/efeitos adversos , Materiais Biocompatíveis/uso terapêutico , Humanos , Hidrogéis/efeitos adversos , Macrófagos/imunologia , Primatas/imunologia
18.
PLoS One ; 10(9): e0137550, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26355958

RESUMO

In vivo implantation of sterile materials and devices results in a foreign body immune response leading to fibrosis of implanted material. Neutrophils, one of the first immune cells to be recruited to implantation sites, have been suggested to contribute to the establishment of the inflammatory microenvironment that initiates the fibrotic response. However, the precise numbers and roles of neutrophils in response to implanted devices remains unclear. Using a mouse model of peritoneal microcapsule implantation, we show 30-500 fold increased neutrophil presence in the peritoneal exudates in response to implants. We demonstrate that these neutrophils secrete increased amounts of a variety of inflammatory cytokines and chemokines. Further, we observe that they participate in the foreign body response through the formation of neutrophil extracellular traps (NETs) on implant surfaces. Our results provide new insight into neutrophil function during a foreign body response to peritoneal implants which has implications for the development of biologically compatible medical devices.


Assuntos
Neutrófilos/imunologia , Neutrófilos/metabolismo , Próteses e Implantes/efeitos adversos , Animais , Citocinas/metabolismo , Armadilhas Extracelulares/imunologia , Armadilhas Extracelulares/metabolismo , Fibrose , Mediadores da Inflamação/metabolismo , Contagem de Leucócitos , Camundongos , Modelos Animais , Infiltração de Neutrófilos/imunologia , Fagocitose/imunologia
19.
Stem Cell Res Ther ; 5(1): 14, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24460869

RESUMO

INTRODUCTION: Although stem cell therapy is a promising treatment for myocardial infarction, the minimal functional improvements observed clinically limit its widespread application. A need exists to maximize the therapeutic potential of these stem cells by first understanding what factors within the infarct microenvironment affect their ability to regenerate the necrotic tissue. In this study, we assessed both differentiation capacity and paracrine signaling as a function of extracellular matrix remodeling after myocardial infarction. METHODS: Mechanical and compositional changes to the decellularized infarcted myocardium were characterized to understand how the extracellular environment, specifically, was altered as a function of time after coronary artery ligation in Sprague-Dawley rats. These alterations were first modeled in a polyacrylamide gel system to understand how the variables of composition and stiffness drive mesenchymal stem cell differentiation towards a cardiac lineage. Finally, the paracrine secretome was characterized as a function of matrix remodeling through gene and protein expression and conditioned media studies. RESULTS: The decellularized infarct tissue revealed significant alterations in both the mechanical and compositional properties of the ECM with remodeling following infarction. This altered microenvironment dynamically regulates the potential for early cardiac differentiation. Whereas Nkx2.5 expression is limited in the presence of chronic remodeled matrix of increased stiffness, GATA4 expression is enhanced. In addition, the remodeled matrix promotes the expression of several proangiogenic, prosurvival, antifibrotic, and immunomodulatory growth factors. In particular, an increase in HGF and SDF1 expression and secretion by mesenchymal stem cells can rescue oxidatively stressed cardiomyocytes in vitro. CONCLUSIONS: This study demonstrated that decellularization of diseased tissue allows for the exclusive analysis of the remodeled matrix and its ability to influence significantly the cellular phenotype. Characterization of cell fate as a function of myocardial remodeling following infarction is critical in developing the ideal strategy for cell implantation to maximize tissue regeneration and to ultimately reduce the prevalence and severity of heart failure.


Assuntos
Matriz Extracelular/metabolismo , Transplante de Células-Tronco Mesenquimais , Infarto do Miocárdio/terapia , Animais , Diferenciação Celular , Células Cultivadas , Quimiocina CXCL12/genética , Quimiocina CXCL12/metabolismo , Fator de Transcrição GATA4/genética , Fator de Transcrição GATA4/metabolismo , Fator de Crescimento de Hepatócito/genética , Fator de Crescimento de Hepatócito/metabolismo , Proteína Homeobox Nkx-2.5 , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Infarto do Miocárdio/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Comunicação Parácrina , Ratos , Ratos Sprague-Dawley , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
20.
Biomaterials ; 34(23): 5792-801, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23660251

RESUMO

Immuno-isolation of islets has the potential to enable the replacement of pancreatic function in diabetic patients. However, host response to the encapsulated islets frequently leads to fibrotic overgrowth with subsequent impairment of the transplanted grafts. Here, we identified and incorporated anti-inflammatory agents into islet-containing microcapsules to address this challenge. In vivo subcutaneous screening of 16 small molecule anti-inflammatory drugs was performed to identify promising compounds that could minimize the formation of fibrotic cell layers. Using parallel non-invasive fluorescent and bioluminescent imaging, we identified dexamethasone and curcumin as the most effective drugs in inhibiting the activities of inflammatory proteases and reactive oxygen species in the host response to subcutaneously injected biomaterials. Next, we demonstrated that co-encapsulating curcumin with pancreatic rat islets in alginate microcapsules reduced fibrotic overgrowth and improved glycemic control in a mouse model of chemically-induced type I diabetes. These results showed that localized administration of anti-inflammatory drug can improve the longevity of encapsulated islets and may facilitate the translation of this technology toward a long-term cure for type I diabetes.


Assuntos
Anti-Inflamatórios/uso terapêutico , Cápsulas/química , Diabetes Mellitus Experimental/terapia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/imunologia , Animais , Anti-Inflamatórios/farmacologia , Catepsinas/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Fibrose , Ilhotas Pancreáticas/efeitos dos fármacos , Ácido Láctico/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/uso terapêutico
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