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1.
Nat Immunol ; 24(11): 1854-1866, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37857825

RESUMO

Microglial involvement in Alzheimer's disease (AD) pathology has emerged as a risk-determining pathogenic event. While apolipoprotein E (APOE) is known to modify AD risk, it remains unclear how microglial apoE impacts brain cognition and AD pathology. Here, using conditional mouse models expressing apoE isoforms in microglia and central nervous system-associated macrophages (CAMs), we demonstrate a cell-autonomous effect of apoE3-mediated microglial activation and function, which are negated by apoE4. Expression of apoE3 in microglia/CAMs improves cognitive function, increases microglia surrounding amyloid plaque and reduces amyloid pathology and associated toxicity, whereas apoE4 expression either compromises or has no effects on these outcomes by impairing lipid metabolism. Single-cell transcriptomic profiling reveals increased antigen presentation and interferon pathways upon apoE3 expression. In contrast, apoE4 expression downregulates complement and lysosomal pathways, and promotes stress-related responses. Moreover, in the presence of mouse endogenous apoE, microglial apoE4 exacerbates amyloid pathology. Finally, we observed a reduction in Lgals3-positive responsive microglia surrounding amyloid plaque and an increased accumulation of lipid droplets in APOE4 human brains and induced pluripotent stem cell-derived microglia. Our findings establish critical isoform-dependent effects of microglia/CAM-expressed apoE in brain function and the development of amyloid pathology, providing new insight into how apoE4 vastly increases AD risk.


Assuntos
Doença de Alzheimer , Camundongos , Animais , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Apolipoproteína E4/genética , Apolipoproteína E4/metabolismo , Microglia/metabolismo , Apolipoproteína E3/genética , Apolipoproteína E3/metabolismo , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Encéfalo , Homeostase , Camundongos Transgênicos
2.
Ann Neurol ; 93(4): 830-843, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36546684

RESUMO

OBJECTIVE: Recent evidence supports a link between increased TDP-43 burden and the presence of an APOE4 gene allele in Alzheimer's disease (AD); however, it is difficult to conclude the direct effect of APOE on TDP-43 pathology due to the presence of mixed AD pathologies. The goal of this study is to address how APOE isoforms impact TDP-43 pathology and related neurodegeneration in the absence of typical AD pathologies. METHODS: We overexpressed human TDP-43 via viral transduction in humanized APOE2, APOE3, APOE4 mice, and murine Apoe-knockout (Apoe-KO) mice. Behavior tests were performed across ages. Animals were harvested at 11 months of age and TDP-43 overexpression-related neurodegeneration and gliosis were assessed. To further address the human relevance, we analyzed the association of APOE with TDP-43 pathology in 160 postmortem brains from autopsy-confirmed amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with motor neuron disease (FTLD-MND) in the Mayo Clinic Brain Bank. RESULTS: We found that TDP-43 overexpression induced motor function deficits, neuronal loss, and gliosis in the motor cortex, especially in APOE2 mice, with much milder or absent effects in APOE3, APOE4, or Apoe-KO mice. In the motor cortex of the ALS and FTLD-MND postmortem human brains, we found that the APOE2 allele was associated with more severe TDP-43-positive dystrophic neurites. INTERPRETATION: Our data suggest a genotype-specific effect of APOE on TDP-43 proteinopathy and neurodegeneration in the absence of AD pathology, with the strongest association seen with APOE2. ANN NEUROL 2023;93:830-843.


Assuntos
Doença de Alzheimer , Esclerose Lateral Amiotrófica , Demência Frontotemporal , Degeneração Lobar Frontotemporal , Doença dos Neurônios Motores , Humanos , Animais , Camundongos , Esclerose Lateral Amiotrófica/genética , Apolipoproteína E2/genética , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Apolipoproteína E4/genética , Apolipoproteína E3 , Gliose/genética , Proteínas de Ligação a DNA/genética , Apolipoproteínas E/genética , Degeneração Lobar Frontotemporal/patologia
3.
J Vasc Surg ; 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38925349

RESUMO

OBJECTIVE: This study aimed to determine the influences of varying severity of sleep apnea syndrome (SAS) on the outcomes after thoracic endovascular aorta repair (TEVAR) in patients with Stanford type B aortic dissection (TBAD). METHODS: This observational study focused on individuals with TBAD plus SAS who received TEVAR between January 2018 and December 2022. Patients were divided into groups according to the results of the portable sleep-breathing monitoring systems (PSMS): mild SAS (MSAS) and moderate-to-severe SAS (MSSAS). Clinical profiles were collected and analyzed. RESULTS: A total of 121 cases with TBAD plus SAS who underwent TEVAR were enrolled in this study. Two groups were formed by stratifying these cases: MSAS (74 cases) and MSSAS (47 cases). The MSSAS cases were found to be older relative to MSAS cases (51.7 ± 8.3 vs. 57.1 ± 12.8 years, p = 0.012) and had a higher body mass index (BMI; 25.7 ± 2.3 vs. 27.0 ± 2.3 kg/m2, p = 0.038). The investigation did not find any appreciable differences between the MSAS and MSSAS groups in terms of complications (endoleak: p = 0.403, SINE: p = 1.000, stent displacement: p = 1.000). However, the MSSAS group exhibited a significantly higher overall mortality rate compared to MSAS group (log-rank p = 0.027). The tendency continued when examining cases with Marfan syndrome (MFS) combined with MSSAS, where the overall mortality rate was significantly greater compared to MFS cases with MSAS (log-rank p = 0.037). The absence of a significant difference was noteworthy in the freedom from reintervention between the MSAS and MSSAS groups (log-rank p = 0.278). The overall mortality rate was significantly higher in MSSAS group even after adjusting for varying potential confounders in the multivariate cox regression analysis (HR 95%CI: 1.875 [1.238-2.586], p = 0.012). A markedly higher rate of distal stent dilation in the MSSAS group was also observed compared to the MSAS group (2.5 [2, 3] vs. 4 [2, 5.5] mm/year, p = 0.029). CONCLUSIONS: MSSAS is associated with a significantly higher risk of overall mortality and dilation rate of the distal stent after TEVAR for TBAD patients. Hence, aggressive efforts to reverse the severity of SAS in time in these individuals appear necessary.

4.
Angew Chem Int Ed Engl ; 63(15): e202319758, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38353649

RESUMO

Fluorinated small molecules are commonly used in functional small-molecule chemistry, and N-difluoromethyl (N-CF2H) compounds are particularly intriguing due to their unique and unexplored physiochemical properties. However, despite limited progress, a general methodological approach to the synthesis of N-CF2H compounds remains elusive. Here, guided by computation, we present a simple and practical protocol to access N-CF2H amides and related carbonyl derivatives. The protocol involves a one-pot conversion of thioformamides through desulfurization-fluorination and acylation, providing N-difluoromethylcarbamoyl fluoride building blocks that can be further diversified to a variety of unexplored N-CF2H carbonyl compounds with rich functionality. Additionally, preliminary studies on their properties and stability showcased their potential application in pharmaceuticals and agrochemicals.

5.
PLoS Genet ; 16(10): e1009157, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33108367

RESUMO

In rice (Oryza sativa), caryopses located on proximal secondary branches (CSBs) have smaller grain size and poorer grain filling than those located on apical primary branches (CPBs), greatly limiting grain yield. However, the molecular mechanism responsible for developmental differences between CPBs and CSBs remains elusive. In this transcriptome-wide expression study, we identified the gene Aspartic Protease 1 (OsAsp1), which reaches an earlier and higher transcriptional peak in CPBs than in CSBs after pollination. Disruption of OsAsp1 expression in the heterozygous T-DNA line asp1-1+/-eliminated developmental differences between CPBs and CSBs. OsAsp1 negatively regulated the transcriptional inhibitor of auxin biosynthesis, OsTAA1 transcriptional inhibition factor 1 (OsTIF1), to preserve indole-3-acetic acid (IAA) apical dominance in CPBs and CSBs. IAA also facilitated OsTIF1 translocation from the endoplasmic reticulum (ER) to the nucleus by releasing the interaction of OsTIF1 with OsAsp1 to regulate caryopses IAA levels via a feedback loop. IAA promoted transcription of OsAsp1 through MADS29 to maintain an OsAsp1 differential between CPBs and CSBs during pollination. Together, these findings provide a mechanistic explanation for the distributed auxin differential between CPBs and CSBs to regulate distinct caryopses development in different rice branches and potential targets for engineering yield improvement in crops.


Assuntos
Ácidos Indolacéticos/metabolismo , Proteínas Nucleares/genética , Oryza/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Ácido Aspártico Proteases/genética , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Retículo Endoplasmático/genética , Regulação da Expressão Gênica de Plantas/genética , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal/genética , Reguladores de Crescimento de Plantas/genética , Polinização/genética
6.
Clin Gastroenterol Hepatol ; 20(8): 1795-1802.e2, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-33662594

RESUMO

OBJECTIVE: There has been increased interest in interventions to promote hepatocellular carcinoma (HCC) surveillance given low utilization and high proportions of late stage detection. Accurate prediction of patients likely versus unlikely to respond to interventions could allow a cost-effective approach to outreach and facilitate targeting more intensive interventions to likely non-responders. DESIGN: We conducted a secondary analysis of a randomized clinical trial evaluating a mailed outreach strategy to promote HCC surveillance among 1200 cirrhosis patients at a safety-net health system between December 2014 and March 2017. We developed regularized logistic regression (RLR) and gradient boosting machine (GBM) algorithm models to predict surveillance completion during each of the 3 screening rounds in a training set (n = 960). Model performance was assessed using multiple performance metrics in an independent test set (n = 240). RESULTS: Among 1200 patients, surveillance was completed in 41-47% of patients over the three rounds. The RLR and GBM models demonstrated good discriminatory accuracy, with area under receiver operating characteristic (AUROC) curves of 0.67 and 0.66 respectively in the first surveillance round and improved to 0.77 by the third surveillance round after incorporating prior screening behavior as a feature. Additional performance characteristics including the Brier score, Hosmer-Lemeshow test and reliability diagrams were also evaluated. The most important variables for the predictive model were prior screening completion status and past primary care contact. CONCLUSIONS: Predictive models can help stratify patients' likelihood to respond to surveillance outreach invitations, facilitating tailored strategies to maximize effectiveness and cost-effectiveness of HCC surveillance population health programs.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/epidemiologia , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/diagnóstico , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/epidemiologia , Programas de Rastreamento , Reprodutibilidade dos Testes
7.
Sheng Li Xue Bao ; 73(2): 233-243, 2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-33903885

RESUMO

There is increasing evidence that long non-coding RNA (lncRNA) plays critical roles in cancer progression. However, the role of long non-coding RNA 00665 (LINC00665) in most cancers is poorly understood. The purpose of the present study was to reveal the functional role of LINC00665 in cervical cancer cells. HeLa cells were subjected to LINC00665 short hairpin RNA (shRNA) or control shRNA treatment to investigate the metastasis and proliferation phenotype of cervical cancer cells in vitro and in vivo. Transcriptome sequencing experiments of HeLa cells in LINC00665 silencing or control group were conducted, and the differentially expressed genes (DEGs) were screened. The DEGs were subjected to Metascape database functional analysis and gene set enrichment analysis. Epithelial-mesenchymal transition (EMT) related markers and a key element of WNT/ß­catenin pathway, CTNNB1 (catenin beta 1), were detected by Western blot and immunofluorescence assay. The results showed that silencing LINC00665 reduced cell viability of Hela cells, up-regulated protein expression level of E-cadherin, down-regulated protein expression levels of N-cadherin, Vimentin and CTNNB1, and inhibited cell migration and invasion of HeLa cells. Bioinformatics analysis results showed that LINC00665 might promote EMT by activating WNT-CTNNB1/ß­catenin signaling pathway. These results indicate that LINC00665 has functions in transcriptional EMT regulation via WNT-CTNNB1/ß­catenin signaling pathway and therefore can be developed as a therapeutic target for cervical cancer.


Assuntos
Transição Epitelial-Mesenquimal , beta Catenina , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Células HeLa , Humanos , RNA Longo não Codificante , Via de Sinalização Wnt , beta Catenina/genética , beta Catenina/metabolismo
8.
Biochem Biophys Res Commun ; 497(2): 639-645, 2018 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-29453983

RESUMO

There is increasing evidence that glycolysis is involved in cancer progression. Aldolase is a glycolytic enzyme that catalyzes the reversible conversion of fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. Disruption of the aldolase genes also plays a role in the progression of multiple types of cancer. However, the underlying mechanism of the action of aldolases in colon cancer progression remains elusive. In this study, aldolase A expression was investigated and found to be upregulated along with human colon cancer progression and metastasis at both the mRNA and protein levels in human colon cancer tissues. In addition, silencing aldolase A suppressed colon cancer cell proliferation and invasion and inhibited the EMT phenotype. Aldolase A protein expression in colon cancer was related to tumor location, tumor clinical stage and survival. Kaplan-Meier analysis showed that high aldolase A protein expression was associated with an unfavorable outcome. Moreover, aldolase A affected the development of colon cancer not only by affecting the glucose metabolism but also by interacting with the HIF-1 and other EMT-related signaling pathways; silencing aldolase A resulted in the reduced activity of these signaling pathways. These results indicate that aldolase A has additional non-glycolytic functions in transcriptional EMT regulation and may therefore have potential as a therapeutic target or a biomarker for identifying patients at risk for poorer survival.


Assuntos
Neoplasias do Colo/genética , Transição Epitelial-Mesenquimal , Frutose-Bifosfato Aldolase/genética , Regulação para Cima , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Colo/metabolismo , Colo/patologia , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/patologia , Progressão da Doença , Feminino , Frutose-Bifosfato Aldolase/análise , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Prognóstico
9.
Langmuir ; 34(3): 1042-1050, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29019694

RESUMO

The molecular structure of zwitterionic and charged monolayers on small oil droplets in aqueous solutions is determined using a combined second harmonic and sum frequency study. From the interfacial vibrational signature of the acyl chains and phosphate headgroups as well as the response of the hydrating water, we find that zwitterionic and charged lipids with identical acyl chains form remarkably different monolayers. Zwitterionic phospholipids form a closely packed monolayer with highly ordered acyl tails. In contrast, the charged phospholipids form a monolayer with a low number density and disordered acyl tails. The charged headgroups are oriented perpendicular to the monolayer rather than parallel, as is the case for zwitterionic lipids. These significant differences between the two types of phospholipids indicate important roles of phospholipid headgroups in the determination of properties of cellular membranes and lipid droplets. The observed behavior of charged phospholipids is different from expectations based on studies performed on extended planar interfaces, at which condensed monolayers are readily formed. The difference can be explained by nanoscale related changes in charge condensation behavior that has its origin in a different balance of interfacial intermolecular interactions.

10.
J Chem Phys ; 148(22): 222835, 2018 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-29907025

RESUMO

The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network of water that show a decrease in the orientational order of water with increasing temperature. Although D2O has a more structured H-bond network (giving rise to more fs-ESHS intensity), the relative temperature dependence is larger in H2O. The changes are interpreted in terms of the symmetry of H-bonds and are indicators of nuclear quantum effects. Increasing the temperature in electrolyte solutions decreases the influence of the total electrostatic field from ions on the water-water correlations, as expected from Debye-Hückel theory, since the Debye length becomes longer. The effects are, however, 1.9 times (6.3 times) larger than those predicted for H2O (D2O). Since fs-ESHS responses can be computed from known molecular coordinates, our observations provide a unique opportunity to refine quantum mechanical models of water.

11.
Chem Biodivers ; 15(1)2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29125222

RESUMO

As natural-product-derived antibiotics, desotamides A - D and wollamides exhibit growth inhibitory activity against Gram-posivite bacteria (IC50 0.6 - 7 µm) and are noncytotoxic to mammalian cells (IC50  > 30 µm). Herein we firstly report the total synthesis of above two cyclohexapeptides as well as a series of structural variants through solid phase peptide synthesis, of which 3 displayed a 2-fold increase of antibacterial activity when compared with the original peptide 1. This strategy may offer good improvements for the synthesis of other cyclic peptides.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Bactérias Gram-Positivas/crescimento & desenvolvimento , Células Hep G2 , Humanos , Células MCF-7 , Testes de Sensibilidade Microbiana , Estrutura Molecular , Peptídeos Cíclicos/síntese química , Peptídeos Cíclicos/química , Relação Estrutura-Atividade
12.
Biochem Biophys Res Commun ; 493(4): 1450-1456, 2017 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-28988107

RESUMO

The calcium-dependent protein kinases (CDPKs) are a class of plant-specific kinase that directly bind Ca2+ and mediate the calcium-signaling pathways to play important physiological roles in growth and development. The rice genome contains 31 CDPK genes, one of which, OsCPK21, is known to modulate the abscisic acid (ABA) and salt stress responses in this crop; however, the molecular mechanisms underlying this regulation are largely unknown. In the present study, we performed yeast two-hybrid screening, glutathione S-transferase pull-down, co-immunoprecipitation, and bimolecular fluorescence complementation assays to confirm the interaction between OsCPK21 and one of its putative targets, Os14-3-3 (OsGF14e). We used an in vitro kinase assay and site-directed mutagenesis to verify that OsCPK21 phosphorylates OsGF14e at Tyr-138. We used real-time PCR to reveal that several ABA and salt inducible genes were more highly expressed in the OsCPK21-OE and OsGF14e WT-OE plants than in the mutant OsGF14e Y138A-OE and wild-type plants. These results suggest that OsCPK21 phosphorylates OsGF14e to facilitate the response to ABA and salt stress.


Assuntos
Proteínas 14-3-3/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas Quinases/metabolismo , Proteínas 14-3-3/química , Proteínas 14-3-3/genética , Ácido Abscísico/metabolismo , Sequência de Aminoácidos , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Mutagênese Sítio-Dirigida , Oryza/genética , Fosforilação , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Proteínas Quinases/síntese química , Proteínas Quinases/genética , Salinidade , Transdução de Sinais , Estresse Fisiológico , Técnicas do Sistema de Duplo-Híbrido
13.
Phys Chem Chem Phys ; 19(36): 24678-24688, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28858349

RESUMO

Specific ion effects in aqueous solutions are investigated at the molecular, nanoscopic and macroscopic levels. Femtosecond elastic second harmonic scattering (fs-ESHS) is used here to assess the chemical effects of ions on molecular and nanoscopic length scales of water, probing changes in the charge distribution around ions as well as structural orientational order of water molecules in extended hydration shells. We measured >0.05 M electrolyte solutions with a series of chloride salts (LiCl, NaCl, KCl, CsCl, RbCl, NH4Cl, MgCl2, CaCl2, and SrCl2). Ion specificity is observed in both the local electronic anisotropy and the nanoscopic orientational ordering of water. Both observables are influenced more by cations with larger valencies and smaller sizes and follow a direct Hofmeister trend. These ion-induced structural changes in the hydrogen-bond network of water are strongly correlated with the viscosity B-coefficient and the Gibbs free energy of hydration of ions. Such a connection between the nanoscopic and macroscopic changes provides a possibility to construct a molecular model for specific ion effects in aqueous solutions.

14.
J Appl Clin Med Phys ; 18(4): 185-192, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28585715

RESUMO

The purpose of this study was to evaluate the changes in magnitude of three-dimensional (3D) liver motion after liver resection/transplantation in patients with hepatocellular carcinoma (HCC) using four-dimensional (4D)-computed tomography (CT) images. From January 2012 to April 2016, 74 HCC patients underwent 4D-CT scans under a free-breathing state to assess respiratory liver motion. Of the 74 patients, 40 did not have a liver resection/transplantation (Group A), 34 with liver resection/transplantation. 15 underwent major or minor resection in the right liver lobe (Group B), 14 underwent major or minor resection in the left liver lobe (Group C), and five underwent liver transplantation (Group D). The 4D-CT images were sorted into 10 image series according to the respiratory phase from the end inspiration to the end expiration, and then transferred to treatment planning software. All liver contours were drawn by a single physician and confirmed by a second. Liver relative coordinates were automatically generated to calculate liver respiratory motion in different axial directions and compiled into a single composite image. Differences in respiratory liver motion were assessed using one-way ANOVA. The average liver respiratory motion in the cranial-caudal direction and 3D magnitude were 10.46 ± 2.78 mm (range, 5.60-18.80 mm) and 11.74 ± 2.65 mm (range, 7.45-20.79 mm) for patients without liver resection/transplantation, and 7.74 ± 2.79 mm (range, 2.20-12.90 mm) and 9.07 ± 2.38 mm (range, 4.79-14.08 mm) for posthepatectomy/post-transplant patients respectively. There were significant differences between Group A and B, Group A and C, Group A and D. However, there were no significant differences among Group B, C, and D. Liver resection/transplantation greatly affected respiratory-induced liver motion in patients with HCC. We, therefore, recommend discriminatory internal target volume (ITV) determination for patients with or without liver resection/transplantation undergoing external radiotherapy for hepatic tumors while respiratory motion management is unavailable.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Hepatectomia , Neoplasias Hepáticas/diagnóstico por imagem , Transplante de Fígado , Movimentos dos Órgãos , Respiração , Tomografia Computadorizada Quadridimensional , Humanos , Fígado/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador
15.
Nano Lett ; 15(8): 5558-63, 2015 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-26151602

RESUMO

A three-dimensional-phospholipid monolayer with tunable molecular structure was created on the surface of oil nanodroplets from a mixture of phospholipids, oil, and water. This simple nanoemulsion preparation technique generates an in situ prepared membrane model system with controllable molecular surface properties that resembles a lipid droplet. The molecular interfacial structure of such a nanoscopic system composed of hexadecane, 1,2-dihexadecanoyl-sn-glycero-3-phosphocholine (DPPC), and water was determined using vibrational sum frequency scattering and second harmonic scattering techniques. The droplet surface structure of DPPC can be tuned from a tightly packed liquid condensed phase like monolayer to a more dilute one that resembles the liquid condensed/liquid expanded coexistence phase by varying the DPPC/oil/water ratio. The tunability of the chemical structure, the high surface-to-volume ratio, and the small sample volume make this system an ideal model membrane for biochemical research.


Assuntos
Emulsões/química , Fosfolipídeos/química , Água/química , Alcanos/química , Nanoestruturas/química , Óleos/química
16.
J Am Chem Soc ; 136(5): 2040-7, 2014 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-24405384

RESUMO

Specific ion effects can influence many processes in aqueous solutions: protein folding, enzyme activity, self-assembly, and interface stabilization. Ionic amphiphiles are known to stabilize the oil/water interface, presumably by dipping their hydrophobic tails into the oil phase while sticking their hydrophilic head groups in water. However, we find that anionic and cationic amphiphiles adopt strikingly different structures at liquid hydrophobic/water interfaces, linked to the different specific interactions between water and the amphiphile head groups, both at the interface and in the bulk. Vibrational sum frequency scattering measurements show that dodecylsulfate (DS(-)) ions do not detectably perturb the oil phase while dodecyltrimethylammonium (DTA(+)) ions do. Raman solvation shell spectroscopy and second harmonic scattering (SHS) show that the respective hydration-shells and the interfacial water structure are also very different. Our work suggests that specific interactions with water play a key role in driving the anionic head group toward the water phase and the cationic head group toward the oil phase, thus also implying a quite different surface stabilization mechanism.


Assuntos
Ácidos Alcanossulfônicos/química , Compostos de Amônio Quaternário/química , Tensoativos/química , Água/química , Interações Hidrofóbicas e Hidrofílicas , Íons , Modelos Moleculares , Análise Espectral Raman , Propriedades de Superfície
17.
J Chem Phys ; 141(18): 18C524, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25399189

RESUMO

The use of a liquid microjet as a possible source of interest for Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) spectroscopy is examined. We measured non-resonant SHG scattering patterns from the air/water interface of a microjet of pure water and observe a strong enhancement of the SHG signal for certain scattering angles. These enhancements can be explained by the optical properties and the shape of the liquid microjet. SFG experiments at the surface of a liquid microjet of ethanol in air show that it is also possible to measure the coherent vibrational SFG spectrum of the ethanol/air interface in this way. Our findings are useful for future far-UV or X-ray based nonlinear optical surface experiments on liquid jets. In addition, combined X-ray photoelectron spectroscopy and SHG/SFG measurements are feasible, which will be very useful in improving our understanding of the molecular foundations of electrostatic and chemical surface properties and phenomena.


Assuntos
Modelos Biológicos , Água/química , Ar , Etanol/química , Espectroscopia Fotoeletrônica , Propriedades de Superfície
18.
Angew Chem Int Ed Engl ; 53(36): 9560-3, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25045022

RESUMO

Guilty as charged: Water is often modeled as a dielectric continuum, but the molecular structure of water is asymmetric. Two ions that have a virtually identical size, shape, and structure, but an opposite charge sign have been investigated to see whether charge makes a fundamental difference to water structuring. The spectroscopic data for the hydration and interface structures are found to be remarkably different for opposite charges.


Assuntos
Água/química , Campos Eletromagnéticos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Íons , Modelos Moleculares , Solubilidade
19.
Chin Med J (Engl) ; 137(11): 1332-1342, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38725345

RESUMO

BACKGROUND: To address the need for immunotherapy in patients with advanced primary hepatocellular carcinoma (HCC), combination with radiotherapy (RT) has emerged as a promising strategy. In preclinical studies, irradiated tumors released tumor antigens to synergistically increase the antitumor effect of immunotherapy. Hence, we investigated whether RT enhances the efficacy of anti-programmed death receptor-1 (PD-1) inhibitors in advanced HCC in real-world practice. METHODS: Between August 2018 and June 2021, 172 patients with advanced primary HCC were enrolled in the tertiary center (Zhongshan Hospital of Fudan University); 95 were treated with a combination of RT and the inhibitor of PD-1 (RT-PD1 cohort), and 77 were administered anti-PD-1 therapy (PD1 cohort). The first cycle of PD-1 inhibitors was administered within 60 days or concurrently with RT. Propensity score matching for bias reduction was used to evaluate the clinical outcomes. RESULTS: Among 71 propensity-matched pairs, median progression-free survival was 5.7 months in the RT-PD1 cohort vs. 2.9 months in the PD1 cohort ( P  <0.001). Median overall survival was 20.9 months in the RT-PD1 cohort vs. 11.2 months in the PD1 cohort ( P  = 0.018). Compared with patients in the PD1 cohort, patients in the RT-PD1 cohort had significantly higher objective response rates (40.8%, 29/71 vs. 19.7%, 14/71, P  = 0.006) and disease control rates (62.0%, 44/71 vs. 31.0%, 22/71, P  <0.001). The incidences of toxic effects were not significantly different between the two cohorts. CONCLUSIONS: RT plus anti-PD-1 therapy is well tolerated. RT enhances the efficacy of anti-PD-1 therapy in patients with advanced primary HCC by improving survival outcomes without increased toxic effects.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Receptor de Morte Celular Programada 1 , Pontuação de Propensão , Humanos , Carcinoma Hepatocelular/radioterapia , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/tratamento farmacológico , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Inibidores de Checkpoint Imunológico/uso terapêutico , Adulto
20.
Clin Transl Radiat Oncol ; 46: 100767, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38576855

RESUMO

Centrally located hepatocellular carcinoma (HCC) is difficult to be radically resected due to its special location close to major hepatic vessels. Thus, we aimed to assess whether stereotactic body radiation therapy (SBRT) can be an effective and safe approach for centrally located HCC. This retrospective study included 172 patients with centrally located HCC who were treated with SBRT. Overall survival (OS) was analyzed as the primary endpoint. Rates of progression-free survival (PFS), local control, intrahepatic relapse, extrahepatic metastasis and toxicities were analyzed as secondary endpoints. The OS rates of 1-, 3-, and 5-year were 97.7%, 86.7%, and 76.3%, respectively. The PFS/local control rates of 1-, 3-, and 5-year were 94.1%/98.2%, 76.8%/94.9%, and 59.3%/92.3%, respectively. The cumulative incidence of intrahepatic relapse/extrahepatic metastases of 1-, 3-, and 5-year were 3.7%/2.9%, 25.0%/7.4%, and 33.3%/9.8%, respectively. Both univariate and multivariate analyses revealed that patients received BED10 at 100 Gy or more had better OS. Radiation-related adverse events were mild to moderate according to Common Terminology Criteria for Adverse Events, and no toxicities over grade 3 were observed. Patients with centrally located HCC in our cohort who received SBRT had similar OS and PFS rates compared to those reported in literatures who received surgery with neoadjuvant or adjuvant intensity-modulated radiation therapy. These results indicate that SBRT is an effective and well-tolerated method for patients with centrally located HCC, suggesting that it may serve as a reasonable alternative treatment for these kind of patients.

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