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1.
Age Ageing ; 51(5)2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35595256

RESUMO

BACKGROUND: SARS-CoV-2 vaccination is the most effective strategy to protect older residents of long-term care facilities (LTCF) against severe COVID-19, but primary vaccine responses are less effective in older adults. Here, we characterised the humoral responses of institutionalised seniors 3 months after they had received the mRNA/BNT162b2 vaccine. METHODS: plasma levels of SARS-CoV-2-specific total IgG, IgM and IgA antibodies were measured before and 3 months after vaccination in older residents of LTCF. Neutralisation capacity was assessed in a pseudovirus neutralisation assay against the original WH1 and later B.1.617.2/Delta variants. A group of younger adults was used as a reference group. RESULTS: three months after vaccination, uninfected older adults presented reduced SARS-CoV-2-specific IgG levels and a significantly lower neutralisation capacity against the WH1 and Delta variants compared with vaccinated uninfected younger individuals. In contrast, COVID-19-recovered older adults showed significantly higher SARS-CoV-2-specific IgG levels after vaccination than their younger counterparts, whereas showing similar neutralisation activity against the WH1 virus and an increased neutralisation capacity against the Delta variant. Although, similarly to younger individuals, previously infected older adults elicit potent cross-reactive immune responses, higher quantities of SARS-CoV-2-specific IgG antibodies are required to reach the same neutralisation levels. CONCLUSIONS: although hybrid immunity seems to be active in previously infected older adults 3 months after mRNA/BNT162b2 vaccination, humoral immune responses are diminished in COVID-19 uninfected but vaccinated older residents of LTCF. These results suggest that a vaccine booster dose should be prioritised for this particularly vulnerable population.


Assuntos
COVID-19 , SARS-CoV-2 , Idoso , Anticorpos Antivirais , Vacina BNT162 , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos , Imunoglobulina G , Assistência de Longa Duração , RNA Mensageiro , Vacinação
2.
Harm Reduct J ; 19(1): 7, 2022 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-35090475

RESUMO

BACKGROUND: Opioid use disorder is a public health problem and treatment variability, coverage and accessibility poses some challenges. The study's objective is to review the impact of interim opioid agonist treatment (OAT), a short-term approach for patients awaiting standard OAT, in terms of treatment retention, access to standard OAT, quality of life and satisfaction with treatment. METHOD: We conducted a systematic review searching MEDLINE, EMBASE, PsycINFO, and CENTRAL up to May 2020. Due to variability between studies and outcome measurements, we did not pool effect estimates and reported a narrative synthesis of findings rating their certainty according to GRADE. RESULTS: We identified 266 unique records and included five randomized trials with some limitations in risk of bias and one observational study limited by selection bias. The studies assessed similar approaches to interim OAT but were compared to three different control conditions. Four studies reported on treatment retention at 4 months or less with no significant differences between interim OAT and waiting list or standard OAT. Two studies reported treatment retention at 12 months with no differences between interim OAT and standard OAT. Two trials assessed access to standard OAT and showed significant differences between interim OAT and waiting list for standard OAT. We rated the quality of evidence for these outcomes as moderate due to the impact of risk of bias. Data on quality of life or satisfaction with treatment was suboptimal. CONCLUSIONS: Interim OAT is likely more effective than a waiting list for standard OAT in access to treatment, and it is probably as effective as standard OAT regarding treatment retention. PROSPERO registration CRD42018116269.


Assuntos
Buprenorfina , Transtornos Relacionados ao Uso de Opioides , Analgésicos Opioides/uso terapêutico , Buprenorfina/uso terapêutico , Humanos , Metadona/uso terapêutico , Estudos Observacionais como Assunto , Tratamento de Substituição de Opiáceos , Transtornos Relacionados ao Uso de Opioides/tratamento farmacológico , Qualidade de Vida
3.
Breast Cancer Res ; 23(1): 42, 2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785053

RESUMO

BACKGROUND: Around 15-20% of primary breast cancers are characterized by HER2 protein overexpression and/or HER2 gene amplification. Despite the successful development of anti-HER2 drugs, intrinsic and acquired resistance represents a major hurdle. This study was performed to analyze the RANK pathway contribution in HER2-positive breast cancer and anti-HER2 therapy resistance. METHODS: RANK and RANKL protein expression was assessed in samples from HER2-positive breast cancer patients resistant to anti-HER2 therapy and treatment-naive patients. RANK and RANKL gene expression was analyzed in paired samples from patients treated with neoadjuvant dual HER2-blockade (lapatinib and trastuzumab) from the SOLTI-1114 PAMELA trial. Additionally, HER2-positive breast cancer cell lines were used to modulate RANK expression and analyze in vitro the contribution of RANK signaling to anti-HER2 resistance and downstream signaling. RESULTS: RANK and RANKL proteins are more frequently detected in HER2-positive tumors that have acquired resistance to anti-HER2 therapies than in treatment-naive ones. RANK (but not RANKL) gene expression increased after dual anti-HER2 neoadjuvant therapy in the cohort from the SOLTI-1114 PAMELA trial. Results in HER2-positive breast cancer cell lines recapitulate the clinical observations, with increased RANK expression observed after short-term treatment with the HER2 inhibitor lapatinib or dual anti-HER2 therapy and in lapatinib-resistant cells. After RANKL stimulation, lapatinib-resistant cells show increased NF-κB activation compared to their sensitive counterparts, confirming the enhanced functionality of the RANK pathway in anti-HER2-resistant breast cancer. Overactivation of the RANK signaling pathway enhances ERK and NF-κB signaling and increases lapatinib resistance in different HER2-positive breast cancer cell lines, whereas RANK loss sensitizes lapatinib-resistant cells to the drug. Our results indicate that ErbB signaling is required for RANK/RANKL-driven activation of ERK in several HER2-positive cell lines. In contrast, lapatinib is not able to counteract the NF-κB activation elicited after RANKL treatment in RANK-overexpressing cells. Finally, we show that RANK binds to HER2 in breast cancer cells and that enhanced RANK pathway activation alters HER2 phosphorylation status. CONCLUSIONS: Our data support a physical and functional link between RANK and HER2 signaling in breast cancer and demonstrate that increased RANK signaling may contribute to the development of lapatinib resistance through NF-κB activation. Whether HER2-positive breast cancer patients with tumoral RANK expression might benefit from dual HER2 and RANK inhibition therapy remains to be elucidated.


Assuntos
Neoplasias da Mama/metabolismo , Resistencia a Medicamentos Antineoplásicos , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Receptor ErbB-2/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Lapatinib/uso terapêutico , NF-kappa B/metabolismo , Terapia Neoadjuvante , Ligação Proteica , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptor ErbB-2/antagonistas & inibidores , Transdução de Sinais , Trastuzumab/uso terapêutico
4.
Depress Anxiety ; 38(5): 528-544, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33393724

RESUMO

BACKGROUND: Healthcare workers are a key occupational group at risk for suicidal thoughts and behaviors (STB). We investigated the prevalence and correlates of STB among hospital workers during the first wave of the Spain COVID-19 outbreak (March-July 2020). METHODS: Data come from the baseline assessment of a cohort of Spanish hospital workers (n = 5450), recruited from 10 hospitals just after the height of the coronavirus disease 2019 (COVID-19) outbreak (May 5-July 23, 2020). Web-based self-report surveys assessed 30-day STB, individual characteristics, and potentially modifiable contextual factors related to hospital workers' work and financial situation. RESULTS: Thirty-day STB prevalence was estimated at 8.4% (4.9% passive ideation only, 3.5% active ideation with or without a plan or attempt). A total of n = 6 professionals attempted suicide in the past 30 days. In adjusted models, 30-day STB remained significantly associated with pre-pandemic lifetime mood (odds ratio [OR] = 2.92) and anxiety disorder (OR = 1.90). Significant modifiable factors included a perceived lack of coordination, communication, personnel, or supervision at work (population-attributable risk proportion [PARP] = 50.5%), and financial stress (PARP = 44.1%). CONCLUSIONS AND RELEVANCE: Thirty-day STB among hospital workers during the first wave of the Spain COVID-19 outbreak was high. Hospital preparedness for virus outbreaks should be increased, and strong governmental policy response is needed to increase financial security among hospital workers.


Assuntos
COVID-19 , Ideação Suicida , Surtos de Doenças , Hospitais , Humanos , Prevalência , Fatores de Risco , SARS-CoV-2 , Espanha/epidemiologia , Estudantes , Tentativa de Suicídio
5.
Environ Sci Technol ; 55(8): 4862-4870, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33764067

RESUMO

We examined the uptake of Tl(I) by two hexagonal birnessites and related phase transformations in laboratory experiments over 12 sequential additions of 0.01 M Tl(I)/Mn at pH 4.0, 6.0, and 8.0. The Tl-reacted Mn oxides were characterized for their structure, Tl binding, and morphology using X-ray diffraction, X-ray photoelectron and X-ray absorption spectroscopies, and transmission electron microscopy. Very limited Tl oxidation was observed in contrast to previous works, where equal Tl(I)/Mn was added in a single step. Instead, both birnessites transformed into a 2 × 2 tunneled phase with dehydrated Tl(I) in its tunnels at pH 4, but only partially at pH 6, and at pH 8.0 they remained layered. The first four to nine sequential Tl(I)/Mn additions resulted in lower residual dissolved Tl+ concentrations than when the same amounts of Tl(I)/Mn were added in single steps. This study thus shows that the repeated reaction of hexagonal birnessites with smaller Tl(I)/Mn at ambient temperature triggers a complete phase conversion with Tl(I) as the sole reacting cation. The novel pathway found may be more relevant for contaminated environments and may help explain the formation of minerals like thalliomelane [Tl+(Mn7.54+Cu0.52+)O16]; it also points to the possibility that other reducing species trigger similar Mn oxide transformation reactions.


Assuntos
Óxidos , Tálio , Concentração de Íons de Hidrogênio , Oxirredução
6.
Ann Vasc Surg ; 73: 429-437, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33387620

RESUMO

BACKGROUND: Based on current evidence, one-time screening for abdominal aortic aneurysm (AAA) in men using ultrasound evaluation reduces mortality related to AAA rupture and is considered cost-effective, although all-cause mortality reduction still remains in question. In Spain, there is no population screening program for AAA, so the aim of our study was to perform a pilot population screening program in our area to assess feasibility and efficiency of an AAA screening program for men and women. METHODS: A population AAA screening pilot program was performed in a Barcelona area, including 400,000 inhabitants. According to inclusion criteria, 4,730 individuals aged 65 years at the moment of the trial were invited for screening (2,089 men and 2,641 women). Primary care doctors, trained in duplex ultrasound abdominal evaluations, performed an abdominal aortic measurement. Individuals with a previous diagnosis of AAA, limited life expectancy, or wrong contact data were excluded. Participation data, aortic diameters, AAA prevalence, and related cardiovascular risk factors were analyzed. The results were used in a cost-utility model to assess the efficiency of the screening program. RESULTS: Participation was 50.3% in men and 44% in women. Eleven patients were excluded because of previously diagnosed AAA. Five new asymptomatic AAA were detected in 65-year-old men (0.5% prevalence), all being active smokers. When considering patients excluded for previous AAA diagnosis, the prevalence in 65-year-old men reached 1.4%. Global AAA prevalence in smoking men reached 2.67%. No AAA was detected in women. Subaneurysmal aorta prevalence in men was 2.9% (n = 29), and in women, it was 0.08% (n = 2). A cost-utility analysis model on screening versus no screening retrieved 13,664€ per quality-adjusted life years at a 10-year horizon and 39,455€ per quality-adjusted life years at a 30-year horizon. CONCLUSIONS: AAA population-based screening by ultrasound evaluation in primary care is logistically feasible in our area. Despite that, AAA prevalence is lower than expected in men, and null in women. Cost-utility model results indicate that a local AAA screening program is only efficient in a 30 years' time horizon. Such inefficient results for a population screening make it necessary to consider other strategies such as opportunistic or subgroup screening in our area.


Assuntos
Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/epidemiologia , Programas de Triagem Diagnóstica , Atenção Primária à Saúde , Ultrassonografia Doppler Dupla , Idoso , Aneurisma da Aorta Abdominal/economia , Análise Custo-Benefício , Programas de Triagem Diagnóstica/economia , Estudos de Viabilidade , Feminino , Custos de Cuidados de Saúde , Humanos , Masculino , Projetos Piloto , Valor Preditivo dos Testes , Prevalência , Anos de Vida Ajustados por Qualidade de Vida , Distribuição por Sexo , Espanha/epidemiologia , Fatores de Tempo , Ultrassonografia Doppler Dupla/economia
7.
Euro Surveill ; 26(25)2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34169818

RESUMO

BackgroundRecent and reliable estimates on the prevalence of coinfection with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) in Europe are lacking.AimLeveraged on a study designed to assess HIV/HCV coinfection prevalence, we assessed the prevalence of HIV/HBV coinfection in Spain in 2018 and compared the results with five similar studies performed since 2002.MethodsThis cross-sectional prevalence study was carried out in 43 centres, and patients were selected using simple random sampling. The reference population comprised 40,322 patients and the sample size were 1,690 patients.ResultsThe prevalence of HIV/HBV coinfection in Spain at the end of 2018 was 3.2%. The prevalence in 2002, 2009, 2015, 2016 and 2017 was 4.9%, 3.4%, 3%, 3.9% and 3%, respectively. Among the HIV/HBV-coinfected patients identified in 2018, 16.7% had cirrhosis according to transient elastography and 26.3% tested positive for antibodies against hepatitis D virus. All HIV/HBV-coinfected patients were receiving drugs with activity against HBV, and 97% of those tested for HBV DNA had an HBV DNA load < 80 IU/mL.ConclusionsThe prevalence of HIV/HBV coinfection in Spain remained stable at around 3% for a decade. Our data could facilitate the design of national programmes to control HBV infection and help identify areas of patient management that need improvement.


Assuntos
Coinfecção , Infecções por HIV , Hepatite B , Coinfecção/epidemiologia , Estudos Transversais , Europa (Continente) , Infecções por HIV/epidemiologia , Hepatite B/epidemiologia , Vírus da Hepatite B , Humanos , Prevalência , Espanha/epidemiologia
8.
Small ; 16(23): e2001307, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32390240

RESUMO

Strongly correlated perovskite oxides are a class of materials with fascinating intrinsic physical functionalities due to the interplay of charge, spin, orbital ordering, and lattice degrees of freedom. Among the exotic phenomena arising from such an interplay, metal-insulator transitions (MITs) are fundamentally still not fully understood and are of large interest for novel nanoelectronics applications, such as resistive switching-based memories and neuromorphic computing devices. In particular, rare-earth nickelates and lanthanum strontium manganites are archetypical examples of bandwidth-controlled and band-filling-controlled MIT, respectively, which are used in this work as a playground to correlate the switching characteristics of the oxides and their MIT properties by means of local probe techniques in a systematic manner. These findings suggest that an electric-field-induced MIT can be triggered in these strongly correlated systems upon generation of oxygen vacancies and establish that lower operational voltages and larger resistance ratios are obtained in those films where the MIT lies closer to room temperature. This work demonstrates the potential of using MITs in the next generation of nanoelectronics devices.

9.
Nano Lett ; 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31185574

RESUMO

Superconductors are essential in many present and future technologies, from large-scale devices for medical imaging, accelerators, or fusion experiments to ultra-low-power superconducting electronics. However, their potential applicability, and particularly that of high-temperature superconductors (HTS), is severely affected by limited performances at large magnetic fields and high temperatures, where their use is most needed. One of the main reasons for these limitations is the presence of quantized vortices, whose movements result in losses, internal noise, and reduced performances. The conventional strategy to overcome the flow of vortices is to pin them along artificial defects. Here, we theoretically and experimentally demonstrate that critical-current density in high-temperature superconductors can reach unprecedented high values at high fields and temperatures by preventing vortex entry. By tailoring the geometry, that is, reducing the width, W, of nanowire-patterned HTS films, the range of the Meissner state, for which no vortices are present, is extended up to very large applied field values, on the order of ∼1 T. Current densities on the order of the depairing current can be sustained under high fields for a wide range of temperatures. Results may be relevant both for devising new conductors carrying depairing-current values at high temperatures and large magnetic fields and for reducing flux noise in sensors and quantum systems.

11.
Breast Cancer Res ; 21(1): 79, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31277676

RESUMO

BACKGROUND: Acquired resistance to trastuzumab is a major clinical problem in the treatment of HER2-positive (HER2+) breast cancer patients. The selection of trastuzumab-resistant patients is a great challenge of precision oncology. The aim of this study was to identify novel epigenetic biomarkers associated to trastuzumab resistance in HER2+ BC patients. METHODS: We performed a genome-wide DNA methylation (450K array) and a transcriptomic analysis (RNA-Seq) comparing trastuzumab-sensitive (SK) and trastuzumab-resistant (SKTR) HER2+ human breast cancer cell models. The methylation and expression levels of candidate genes were validated by bisulfite pyrosequencing and qRT-PCR, respectively. Functional assays were conducted in the SK and SKTR models by gene silencing and overexpression. Methylation analysis in 24 HER2+ human BC samples with complete response or non-response to trastuzumab-based treatment was conducted by bisulfite pyrosequencing. RESULTS: Epigenomic and transcriptomic analysis revealed the consistent hypermethylation and downregulation of TGFBI, CXCL2, and SLC38A1 genes in association with trastuzumab resistance. The DNA methylation and expression levels of these genes were validated in both sensitive and resistant models analyzed. Of the genes, TGFBI presented the highest hypermethylation-associated silencing both at the transcriptional and protein level. Ectopic expression of TGFBI in the SKTR model suggest an increased sensitivity to trastuzumab treatment. In primary tumors, TGFBI hypermethylation was significantly associated with trastuzumab resistance in HER2+ breast cancer patients. CONCLUSIONS: Our results suggest for the first time an association between the epigenetic silencing of TGFBI by DNA methylation and trastuzumab resistance in HER2+ cell models. These results provide the basis for further clinical studies to validate the hypermethylation of TGFBI promoter as a biomarker of trastuzumab resistance in HER2+ breast cancer patients.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/genética , Resistencia a Medicamentos Antineoplásicos/genética , Epigênese Genética , Proteínas da Matriz Extracelular/genética , Inativação Gênica , Fator de Crescimento Transformador beta/genética , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Ilhas de CpG , Metilação de DNA , Proteínas da Matriz Extracelular/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Gradação de Tumores , Estadiamento de Neoplasias , Regiões Promotoras Genéticas , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Análise de Sequência de DNA , Fator de Crescimento Transformador beta/metabolismo , Trastuzumab/farmacologia , Trastuzumab/uso terapêutico
12.
Eur J Public Health ; 29(3): 419-424, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30521035

RESUMO

BACKGROUND: Medication adherence is a complex area of behaviour. Little is known about what influences chronic patients to take their medicines. This study has aimed to compare and contrast the health-related beliefs, experiences and types of behaviour typical among patients who have at least one chronic condition and are following a pharmacological treatment in accordance with their level of medication adherence. METHODS: A questionnaire-based cross-sectional study, consisting of socio-demographic data, the 4-item Morisky-Green scale and 37 statements about health beliefs, perceptions and experiences, was conducted at different levels of healthcare (primary and tertiary settings). RESULTS: A total of 577 questionnaires were analyzed. Respondents had a mean age of 64 and took an average of 4.6 drugs. Optimal adherence was reported by 58.6% of respondents. Bivariate analysis showed adherent subjects were older, took more medications, were in better spirits and had greater confidence and information regarding their treatment. Multivariate analysis found older age and the statements 'My doctor periodically reviews my treatment' and 'I am motivated to continue with the treatment' to be significantly related to medication adherence, while 'I make variations when taking medication depending on how I feel' was significant for medication non-adherence. CONCLUSION: Medication non-adherence is common among chronic patients. Patient-centred approaches should be implemented in daily clinical practice as patient health beliefs, experiences and conduct influence medication-taking. Motivational interviewing might improve medication adherence in permitting emotional state managing and increasing educational skills, patient motivation and confidence between patients and healthcare providers.


Assuntos
Adesão à Medicação/estatística & dados numéricos , Doença Crônica , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polimedicação , Espanha , Inquéritos e Questionários , População Urbana
13.
Molecules ; 24(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875891

RESUMO

Recent studies showed that Fatty Acid Synthase (FASN), a lipogenic enzyme overexpressed in several carcinomas, plays an important role in drug resistance. Furthermore, the enrichment of Breast Cancer Stem Cell (BCSC) features has been found in breast tumors that progressed after chemotherapy. Hence, we used the triple negative breast cancer (TNBC) cell line MDA-MB-231 (231) to evaluate the FASN and BCSC population role in resistance acquisition to chemotherapy. For this reason, parental cell line (231) and its derivatives resistant to doxorubicin (231DXR) and paclitaxel (231PTR) were used. The Mammosphere-Forming Assay and aldehyde dehydrogenase (ALDH) enzyme activity assay showed an increase in BCSCs in the doxorubicin-resistant model. Moreover, the expression of some transcription factors involved in epithelial-mesenchymal transition (EMT), a process that confers BCSC characteristics, was upregulated after chemotherapy treatment. FASN inhibitors C75, (-)-Epigallocatechin 3-gallate (EGCG), and its synthetic derivatives G28, G56 and G37 were used to evaluate the effect of FASN inhibition on the BCSC-enriched population in our cell lines. G28 showed a noticeable antiproliferative effect in adherent conditions and, interestingly, a high mammosphere-forming inhibition capacity in all cell models. Our preliminary results highlight the importance of studying FASN inhibitors for the treatment of TNBC patients, especially those who progress after chemotherapy.


Assuntos
Antineoplásicos/farmacologia , Catequina/análogos & derivados , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ácido Graxo Sintase Tipo I/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Antineoplásicos/química , Catequina/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Doxorrubicina/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Estrutura Molecular , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Paclitaxel/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico
14.
J Am Chem Soc ; 140(6): 2127-2134, 2018 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-29308645

RESUMO

Ligand-to-surface interactions are critical factors in surface and interface chemistry to control the mechanisms governing nanostructured colloidal suspensions. In particular, molecules containing carboxylate moieties (such as citrate anions) have been extensively investigated to stabilize metal, metal oxide, and metal fluoride nanoparticles. Using YF3 nanoparticles as a model system, we show here the self-assembly of citrate-stabilized nanostructures (supraparticles) with a size tunable by temperature. Results from several experimental techniques and molecular dynamics simulations show that the self-assembly of nanoparticles into supraparticles is due to ionic bridges between different nanoparticles. These interactions were caused by cations (e.g., ammonium) strongly adsorbed onto the nanoparticle surface that also interact strongly with nonbonded citrate anions, creating ionic bridges in solution between nanoparticles. Experimentally, we observe self-assembly of nanoparticles into supraparticles at 25 and 100 °C. Interestingly, at high temperatures (100 °C), this citrate-bridge self-assembly mechanism is more efficient, giving rise to larger supraparticles. At low temperatures (5 °C), this mechanism is not observed, and nanoparticles remain stable. Molecular dynamics simulations show that the free energy of a single citrate bridge between nanoparticles in solution is much larger than the thermal energy and in fact is much larger than typical adsorption free energies of ions on colloids. Summarizing our experiments and simulations, we identify as key aspects of the self-assembly mechanism the requirement of NPs with a surface able to adsorb anions and cations and the presence of multidentate ions in solution. This indicates that this new ion-mediated self-assembly mechanism is not specific of YF3 and citrate anions, as supported by preliminary experimental results in other systems.

15.
PLoS Pathog ; 12(8): e1005829, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27541004

RESUMO

Macrophages are a heterogeneous cell population strongly influenced by differentiation stimuli that become susceptible to HIV-1 infection after inactivation of the restriction factor SAMHD1 by cyclin-dependent kinases (CDK). Here, we have used primary human monocyte-derived macrophages differentiated through different stimuli to evaluate macrophage heterogeneity on cell activation and proliferation and susceptibility to HIV-1 infection. Stimulation of monocytes with GM-CSF induces a non-proliferating macrophage population highly restrictive to HIV-1 infection, characterized by the upregulation of the G1/S-specific cyclin D2, known to control early steps of cell cycle progression. Knockdown of cyclin D2, enhances HIV-1 replication in GM-CSF macrophages through inactivation of SAMHD1 restriction factor by phosphorylation. Co-immunoprecipitation experiments show that cyclin D2 forms a complex with CDK4 and p21, a factor known to restrict HIV-1 replication by affecting the function of the downstream cascade that leads to SAMHD1 deactivation. Thus, we demonstrate that cyclin D2 acts as regulator of cell cycle proteins affecting SAMHD1-mediated HIV-1 restriction in non-proliferating macrophages.


Assuntos
Ciclina D2/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Macrófagos/imunologia , Animais , Proliferação de Células , Quinase 4 Dependente de Ciclina/imunologia , Inibidor de Quinase Dependente de Ciclina p21/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Humanos , Macrófagos/virologia , Camundongos , Proteínas Monoméricas de Ligação ao GTP/imunologia , Proteína 1 com Domínio SAM e Domínio HD
16.
Orig Life Evol Biosph ; 48(2): 181-200, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29392543

RESUMO

Any proposed model of Earth's primitive environments requires a combination of geochemical variables. Many experiments are prepared in aqueous solutions and in the presence of minerals. However, most sorption experiments are performed in distilled water, and just a few in seawater analogues, mostly inconsistent with a representative primitive ocean model. Therefore, it is necessary to perform experiments that consider the composition and concentration of dissolved salts in the early ocean to understand how these variables could have affected the absorption of organic molecules into minerals. In this work, the adsorption of adenine, adenosine, and 5'AMP onto Na+montmorillonite was studied using a primitive ocean analog (4.0 Ga) from experimental and computational approaches. The order of sorption of the molecules was: 5'AMP > adenine > adenosine. Infrared spectra showed that the interaction between these molecules and montmorillonite occurs through the NH2 group. In addition, electrostatic interaction between negatively charged montmorillonite and positively charge N1 of these molecules could occur. Results indicate that dissolved salts affect the sorption in all cases; the size and structure of each organic molecule influence the amount sorbed. Specifically, the X-ray diffraction patterns show that dissolved salts occupy the interlayer space in Na-montmorillonite and compete with organic molecules for available sites. The adsorption capacity is clearly affected by dissolved salts in thermodynamic terms as deduced by isotherm models. Indeed, molecular dynamic models suggest that salts are absorbed in the interlamellar space and can interact with oxygen atoms exposed in the edges of clay or in its surface, reducing the sorption of the organic molecules. This research shows that the sorption process could be affected by high concentration of salts, since ions and organic molecules may compete for available sites on inorganic surfaces. Salt concentration in primitive oceans may have strongly affected the sorption, and hence the concentration processes of organic molecules on minerals.


Assuntos
Adenina/química , Monofosfato de Adenosina/química , Adenosina/química , Bentonita/química , Salinidade , Sódio/química , Adsorção , Origem da Vida
17.
Int J Mol Sci ; 19(10)2018 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-30322103

RESUMO

Breast cancer stem cells (BCSCs) are tumor-initiating cells responsible for metastasis and tumor reappearance, but their research is limited by the impossibility to cultivate them in a monolayer culture. Scaffolds are three-dimensional (3D) cell culture systems which avoid problems related with culturing BCSC. However, a standardized scaffold for enhancing a BCSC population is still an open issue. The main aim of this study is to establish a suitable poly (lactic acid) (PLA) scaffold which will produce BCSC enrichment, thus allowing them to be studied. Different 3D printing parameters were analyzed using Taguchi experimental design methods. Several PLA scaffold architectures were manufactured using a Fused Filament Fabrication (FFF) 3D printer. They were then evaluated by cell proliferation assay and the configurations with the highest growth rates were subjected to BCSC quantification by ALDH activity. The design SS1 (0.2 mm layer height, 70% infill density, Zigzag infill pattern, 45° infill direction, and 100% flow) obtained the highest proliferation rate and was capable of enhancing a ALDH+ cell population compared to 2D cell culture. In conclusion, the data obtained endorse the PLA porous scaffold as useful for culturing breast cancer cells in a microenvironment similar to in vivo and increasing the numbers of BCSCs.


Assuntos
Técnicas de Cultura de Células/métodos , Poliésteres/química , Neoplasias de Mama Triplo Negativas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Humanos , Células-Tronco Neoplásicas/patologia , Impressão Tridimensional , Alicerces Teciduais/química
18.
Molecules ; 23(9)2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30200262

RESUMO

Despite advances in breast cancer diagnosis and treatment, many patients still fail therapy, resulting in disease progression, recurrence, and reduced overall survival. Historically, much focus has been put on the intrinsic subtyping based in the presence (or absence) of classical immunohistochemistry (IHC) markers such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-related protein (HER2). However, it is widely understood that tumors are composed of heterogeneous populations of cells with a hierarchical organization driven by cancer stem cells (CSCs). In breast tumors, this small population of cells displaying stem cell properties is known as breast CSCs (BCSCs). This rare population exhibit a CD44⁺/CD24-/low phenotype with high ALDH activity (ALDH⁺), and possesses higher tolerability to chemotherapy, hormone therapy, and radiotherapy and is able to reproduce the bulk of the tumor after reduction of cell populations sensitive to first-line therapy leading to disease relapse. In this review, we present special attention to BCSCs with future directions in the establishment of a therapy targeting this population. Drugs targeting the main BCSCs signaling pathways undergoing clinical trials are also summarized.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Resistencia a Medicamentos Antineoplásicos , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Animais , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios Clínicos como Assunto , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Terapia de Alvo Molecular , Transdução de Sinais/efeitos dos fármacos , Resultado do Tratamento
19.
Molecules ; 23(5)2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29751678

RESUMO

(-)-Epigallocatechin 3-gallate (EGCG) is a natural polyphenol from green tea with reported anticancer activity and capacity to inhibit the lipogenic enzyme fatty acid synthase (FASN), which is overexpressed in several human carcinomas. To improve the pharmacological profile of EGCG, we previously developed a family of EGCG derivatives and the lead compounds G28, G37 and G56 were characterized in HER2-positive breast cancer cells overexpressing FASN. Here, diesters G28, G37 and G56 and two G28 derivatives, monoesters M1 and M2, were synthesized and assessed in vitro for their cytotoxic, FASN inhibition and apoptotic activities in MDA-MB-231 triple-negative breast cancer (TNBC) cells. All compounds displayed moderate to high cytotoxicity and significantly blocked FASN activity, monoesters M1 and M2 being more potent inhibitors than diesters. Interestingly, G28, M1, and M2 also diminished FASN protein expression levels, but only monoesters M1 and M2 induced apoptosis. Our results indicate that FASN inhibition by such polyphenolic compounds could be a new strategy in TNBC treatment, and highlight the potential anticancer activities of monoesters. Thus, G28, G37, G56, and most importantly M1 and M2, are anticancer candidates (alone or in combination) to be further characterized in vitro and in vivo.


Assuntos
Antineoplásicos/síntese química , Catequina/análogos & derivados , Inibidores Enzimáticos/síntese química , Ácido Graxo Sintases/antagonistas & inibidores , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Catequina/síntese química , Catequina/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Estrutura Molecular , Neoplasias de Mama Triplo Negativas/enzimologia
20.
Angew Chem Int Ed Engl ; 57(45): 14747-14751, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-30216611

RESUMO

A fast and single-step preparation of patchy LnF3 faceted-charge nanocrystals are described. These hexagonal faceted nanocrystals allow the spontaneous selective adsorption of cations or anions in the different faces, producing stable and well-defined patches of different charge. The mechanism for the formation of the patches and the properties of the obtained nanocrystals were characterized by a combination of experimental techniques and all-atomic molecular dynamics simulations. The spontaneous dual-charged surface as well as the luminescence effects that can be achieved by doping host-LaF3 systems make these new nanocrystals interesting both from a fundamental point of view and for a wide range of applications.

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