Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 419
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Arch Biochem Biophys ; 754: 109962, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38499055

RESUMO

Acetohydroxyacid synthase (AHAS) is one of the key enzymes of the biosynthesis of branched-chain amino acids, it is also an effective target for the screening of herbicides and antibiotics. In this study we present a method for preparing Escherichia coli AHAS I holoenzyme (EcAHAS I) with exceptional stability, which provides a solid ground for us to re-investigate the in vitro catalytic properties of the protein. The results show EcAHAS I synthesized in this way exhibits similar function to Bacillus subtilis acetolactate synthase in its catalysis with pyruvate and 2-ketobutyrate (2-KB) as dual-substrate, producing four 2-hydroxy-3-ketoacids including (S)-2-acetolactate, (S)-2-aceto-2-hydroxybutyrate, (S)-2-propionyllactate, and (S)-2-propionyl-2-hydroxybutyrate. Quantification of the reaction indicates that the two substrates almost totally consume, and compound (S)-2-aceto-2- hydroxybutyrate forms in the highest yield among the four major products. Moreover, the protein also condenses two molecules of 2-KB to furnish (S)-2-propionyl-2-hydroxybutyrate. Further exploration manifests that EcAHAS I ligates pyruvate/2-KB and nitrosobenzene to generate two arylhydroxamic acids N-hydroxy-N-phenylacetamide and N-hydroxy-N-phenyl- propionamide. These findings enhance our comprehension of the catalytic characteristics of EcAHAS I. Furthermore, the application of this enzyme as a catalyst in construction of C-N bonds displays promising potential.


Assuntos
Acetolactato Sintase , Escherichia coli , Acetolactato Sintase/química , Glicogênio Sintase , Hidroxibutiratos , Piruvatos , Holoenzimas
2.
BMC Ophthalmol ; 24(1): 270, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38914965

RESUMO

BACKGROUND: This study aimed to explore differences in vitreous humour metabolites and metabolic pathways between patients with and without diabetic retinopathy (DR) and identify potential metabolite biomarkers. METHODS: Clinical data and vitreous fluid samples were collected from 125 patients (40 without diabetes, 85 with DR). The metabolite profiles of the vitreous fluid samples were analysed using ultra-high performance liquid chromatography, Q-Exactive mass spectrometry, and multivariate statistical analysis. A machine learning model based on Least Absolute Shrinkage and Selection Operator Regularized logistic regression was used to build a risk scoring model based on selected metabolite levels. Candidate metabolites were regressed to glycated haemoglobin levels by a logistic regression model. RESULTS: Twenty differential metabolites were identified between the DR and control groups and were significantly enriched in five Kyoto Encyclopedia of Genes and Genomes pathways (arginine biosynthesis; tricarboxylic acid cycle; alanine, aspartate, and glutamate metabolism; tyrosine metabolism; and D-glutamate metabolism). Ferrous ascorbate significantly contributes to poorer glycaemic control outcomes, offering insights into potential new pathogenic pathways in DR. CONCLUSIONS: Disorders in the metabolic pathways of arginine biosynthesis, tricarboxylic acid cycle, alanine, aspartate, glutamate metabolism, tyrosine metabolism, and D-glutamate metabolism were associated with DR. Risk scores based on vitreous fluid metabolites can be used for the diagnosis and management of DR. Ferrous ascorbate can provide insights into potential new pathogenic pathways for DR.


Assuntos
Ácido Ascórbico , Biomarcadores , Retinopatia Diabética , Metabolômica , Corpo Vítreo , Humanos , Retinopatia Diabética/metabolismo , Retinopatia Diabética/diagnóstico , Corpo Vítreo/metabolismo , Biomarcadores/metabolismo , Masculino , Metabolômica/métodos , Feminino , Pessoa de Meia-Idade , Ácido Ascórbico/metabolismo , Idoso , Cromatografia Líquida de Alta Pressão
3.
J Am Chem Soc ; 145(5): 3187-3195, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36700656

RESUMO

Supramolecular host-guest ferroelectrics based on solution processing are highly desirable because they are generally created with intrinsic piezoelectricity/ferroelectricity and do not need further poling. Poly(vinylidene fluoride) (PVDF) in the electric-active beta phase after stretching/annealing still shows no piezoelectric response unless poled. Although many supramolecular host-guest ferroelectrics have been discovered, their piezoelectricity is relatively small. Based on H/F substitution, we reported a supramolecular host-guest compound [(CF3-C6H4-NH3)(18-crown-6)][TFSA] (CF3-C6H4-NH3 = 4-trifluoromethylanilinium, TFSA = bis(trifluoromethanesulfonyl)ammonium) with a remarkable piezoelectric response of 42 pC/N under no poling condition. The introduction of F atoms increases phase transition temperature, polar axes, second harmonic generation (SHG) intensity, and piezoelectric coefficient d33. To our knowledge, such a large piezoelectric performance of [(CF3-C6H4-NH3)(18-crown-6)][TFSA] makes its d33, piezoelectric voltage coefficient g33, and mechanical quality factor Qm the highest among the reported supramolecular host-guest ferroelectric compounds and even larger than the values of PVDF. This work provides inspiration for optimizing piezoelectricity on molecular materials.

4.
J Am Chem Soc ; 145(8): 4892-4899, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36795554

RESUMO

Metal-free perovskites with light weight and eco-friendly processability have received great interest in recent years due to their superior physical features in ferroelectrics, X-ray detection, and optoelectronics. The famous metal-free perovskite ferroelectric MDABCO-NH4-I3 (MDABCO = N-methyl-N'-diazabicyclo[2.2.2]octonium) has been demonstrated to exhibit excellent ferroelectricity comparable to that of inorganic ceramic ferroelectric BaTiO3, such as large spontaneous polarization and high Curie temperature (Ye et al. Science 2018, 361, 151). However, piezoelectricity as a vitally important index is far from enough in the metal-free perovskite family. Here, we report the discovery of large piezoelectric response in a new metal-free three-dimensional perovskite ferroelectric NDABCO-NH4-Br3 (NDABCO = N-amino-N'-diazabicyclo[2.2.2]octonium) by replacing the methyl group of MDABCO with the amino group. Besides the evident ferroelectricity, strikingly, NDABCO-NH4-Br3 shows a large d33 of 63 pC/N more than 4 times that of MDABCO-NH4-I3 (14 pC/N). The d33 value is also strongly supported by the computational study. To the best of our knowledge, such a large d33 value ranks the highest among the documented organic ferroelectric crystals to date and represents a major breakthrough in metal-free perovskite ferroelectrics. Combined with decent mechanical properties, NDABCO-NH4-Br3 is expected to be a competitive candidate for medical, biomechanical, wearable, and body-compatible ferroelectric devices.

5.
J Am Chem Soc ; 145(42): 23292-23299, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37819908

RESUMO

Fullerenes offer versatile functionalities and are promising materials for a widespread range of applications from biomedicine and energy to electronics. Great efforts have been made to manipulate the symmetries of fullerene and its derivatives for studying material properties and novel effects, such as ferroelectricity with polar symmetry; however, no documentary report has been obtained to realize their ferroelectricity. Here, for the first time, we demonstrated clear ferroelectricity in a fullerene adduct formed by C60 and S8. More is different: the combination of the most symmetric molecule C60 with the highest Ih symmetry and molecule S8 with high D4d symmetry resulted in the polar C60S8 adduct with a low crystallographic symmetry of the C2v (mm2) point group at room temperature. The presented C60S8 undergoes polar-to-polar ferroelectric phase transition with the mm2Fm notation, whose ferroelectricity was confirmed by a ferroelectric hysteresis loop and ferroelectric domain switching. This finding opens up a new functionality for fullerenes and sheds light on the exploration of more ferroelectric fullerenes.

6.
J Am Chem Soc ; 145(3): 1936-1944, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36637030

RESUMO

Piezoelectric materials that enable electromechanical conversion have great application value in actuators, transducers, sensors, and energy harvesters. Large piezoelectric (d33) and piezoelectric voltage (g33) coefficients are highly desired and critical to their practical applications. However, obtaining a material with simultaneously large d33 and g33 has long been a huge challenge. Here, we reported a hybrid perovskite ferroelectric [Me3NCH2Cl]CdBrCl2 to mitigate and roughly address this issue by heavy halogen substitution. The introduction of a large-size halide element softens the metal-halide bonds and reduces the polarization switching barrier, resulting in excellent piezoelectric response with a large d33 (∼440 pC/N), which realizes a significant optimization compared with that of previously reported [Me3NCH2Cl]CdCl3 (You et al. Science2017, 357, 306-309). More strikingly, [Me3NCH2Cl]CdBrCl2 simultaneously shows a giant g33 of 6215 × 10-3 V m/N, far exceeding those of polymers and conventional piezoelectric ceramics. Combined with simple solution preparation, easy processing of thin films, and a high Curie temperature of 373 K, these attributes make [Me3NCH2Cl]CdBrCl2 promising for high-performance piezoelectric sensors in flexible, wearable, and biomechanical devices.

7.
Small ; 19(44): e2302197, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37403302

RESUMO

Synaptic devices that mimic biological synapses are considered as promising candidates for brain-inspired devices, offering the functionalities in neuromorphic computing. However, modulation of emerging optoelectronic synaptic devices has rarely been reported. Herein, a semiconductive ternary hybrid heterostructure is prepared with a D-D'-A configuration by introducing polyoxometalate (POM) as an additional electroactive donor (D') into a metalloviologen-based D-A framework. The obtained material features an unprecedented porous 8-connected bcu-net that accommodates nanoscale [α-SiW12 O40 ]4- counterions, displaying uncommon optoelectronic responses. Besides, the fabricated synaptic device based on this material can achieve dual-modulation of synaptic plasticity due to the synergetic effect of electron reservoir POM and photoinduced electron transfer. And it can successfully simulate learning and memory processes similar to those in biological systems. The result provides a facile and effective strategy to customize multi-modality artificial synapses in the field of crystal engineering, which opens a new direction for developing high-performance neuromorphic devices.

8.
Haematologica ; 108(9): 2444-2453, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36815381

RESUMO

Grade (G) 3B follicular lymphoma (FL) is a rare FL subtype which exists on a histological continuum between 'lowgrade' (Grade 1, 2 and 3A FL) and diffuse large B-cell lymphoma (DLBCL) appearing to share features with each. Clinical characteristics and outcomes are poorly understood due to lack of adequate representation in prospective trials and large-scale analyses. We analyzed 157 G3BFL cases from 18 international centers, and two comparator groups; G3AFL (n=302) and DLBCL (n=548). Composite histology with DLBCL or low-grade FL occurred in approximately half of the G3BFL cases. With a median of 5 years follow-up, the overall survival and progression-free survival of G3BFL patients was better than that of DLBCL patients (P<0.001 and P<0.001, respectively); however, G3BFL patients were younger (P<0.001) with better performance status (P<0.001), less extranodal disease (P<0.001) and more frequently had normal lactate dehydrogenase (P<0.001) at baseline. The overall and progression-free survival of patients with G3BFL and G3AFL were similar (P=0.83 and P=0.80, respectively). After frontline immunochemotherapy, 24% of G3BFL relapsed; relapse rates were 63% in the DLBCL cohort and 19% in the low-grade FL cohort. Eight percent of relapses occurred beyond 5 years. In this G3BFL cohort, the revised International Prognostic Index successfully delineated risk groups, but the Follicular Lymphoma International Prognostic Index did not. We conclude that patients with immunochemotherapy-treated G3BFL have similar survival outcomes to those with G3AFL, yet a favorable baseline profile and distinctly superior prognosis compared to patients with DLBCL.


Assuntos
Linfoma Folicular , Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Humanos , Linfoma Folicular/diagnóstico , Linfoma Folicular/tratamento farmacológico , Estudos Prospectivos , Recidiva Local de Neoplasia , Linfoma não Hodgkin/patologia , Prognóstico , Linfoma Difuso de Grandes Células B/diagnóstico , Linfoma Difuso de Grandes Células B/tratamento farmacológico
9.
Inorg Chem ; 62(14): 5543-5552, 2023 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-36995797

RESUMO

Bistable materials with multiphysical channels, such as optical, electrical, and magnetic properties, have been paid dramatic attention due to their alternativity of the signal status in electronic devices. Herein, three stable supramolecular radicals ([(NH3-TEMPO)(18-crown-6)][XF6] (1, X = P; 2, X = As; 3, X = Sb)) were synthesized and characterized. The former two molecules present ferroelectric phase transitions around 381.7 and 382.7 K, respectively, with bistability in dielectric property and second-harmonic generation (SHG) effect, which are first found in supramolecular radicals. Their ferroelectric transition and bistable properties are generated from a net polar crystal structure owing to the static ordered packing of NH3-TEMPO radical cations in the low-temperature phase (LTP) to a nonpolar structure owing to a distinctive symmetric scissoring motion of NH3-TEMPO radical cations between two 18-crown-6 molecules in the high-temperature phase (HTP). Both of them exhibit paramagnetic properties in HTP and LTP states since no intermolecular spin-spin interaction occurs due to the long distances among the radicals in their crystals. These results make us possible to design bistable optoelectronic radical materials with bistability in magnetic property in the future.

10.
Inorg Chem ; 62(49): 19930-19936, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-37990884

RESUMO

Organic-inorganic hybrid perovskites (OIHPs) have been emerging as a hot research topic due to their potential applications in energy storage, semiconductors, and electronic devices. Herein, we systematically investigated the synthesis and phase transition behaviors of the enantiomeric OIHPs, (R) and (S)-N,N-dimethyl-3-fluoropyrrolidinium cadmium bromide ([DMFP][CdBr3]), and the hybrid trigonal structure [DMFP]3 (CdBr3)(CdBr4). The enantiomers have a mirror-symmetric structure and enhanced solid-state phase transition points of 417 and 443 K, in contrast to the nonfluorinated parent compound, N,N-dimethyl-pyrrolidinium cadmium bromide ([DMP][CdBr3], 385 K). Moreover, racemic H/F substitution on the pyrrolidinium cations leads to the formation of a trigonal compound, showing above-room-temperature structural phase transition and dominant ferroelasticity. This work discovers chiral enantiomeric OIHPs through H/F substitution, demonstrating a useful chemical synthesis strategy for exploring novel phase transition materials.

11.
Endocr Pract ; 29(9): 710-715, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37385530

RESUMO

OBJECTIVE: Obesity has become an epidemic in the United States. Although bariatric surgery can effectively achieve weight loss by altering the gastrointestinal tract, it commonly results in micronutrient deficiency, requiring supplementation. Iodine is an essential micronutrient for the synthesis of thyroid hormones. We aimed to investigate changes in urinary iodine concentrations (UIC) in patients following bariatric surgery. METHODS: 85 adults who underwent either laparoscopic sleeve gastrectomy or laparoscopic Roux-en-Y gastric bypass surgery were enrolled. At baseline and 3 months after surgery, we evaluated spot UIC and serum thyroid stimulating hormone (TSH), vitamin D, vitamin B12, ferritin, and folate levels. Participants provided a 24-hour diet recall for iodine-rich foods and information about multivitamin use at each time point. RESULTS: There was a significant increase in median UIC (201 [120.0 - 288.5] vs 334.5 [236.3 - 740.3] µg/L; P < .001), a significant decrease in mean body mass index (44.0 ± 6.2 vs 35.8 ± 5.9; P < .001) and a significant decrease in TSH levels (1.5 [1.2 - 2.0] vs 1.1 [0.7 - 1.6] uIU/mL; P < .001) at 3 months postoperatively compared to baseline. Body mass index, UIC, and TSH levels before and after surgery did not differ based on the type of weight loss surgery. CONCLUSION: In an iodine-sufficient area, bariatric surgery does not cause iodine deficiency nor clinically significant changes in thyroid function. Different surgical procedures with different anatomical alterations in the gastrointestinal tract do not significantly affect iodine status.


Assuntos
Cirurgia Bariátrica , Derivação Gástrica , Iodo , Obesidade Mórbida , Adulto , Humanos , Obesidade Mórbida/cirurgia , Obesidade Mórbida/epidemiologia , Iodo/urina , Tireotropina , Vitaminas
12.
Int J Lang Commun Disord ; 58(3): 802-812, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36412089

RESUMO

BACKGROUND: Much has been written about the changes in use and perspectives of telepractice among speech and language therapists (SLTs) during the global COVID-19 pandemic. However, no long-term study has been done to examine whether there is a permanent shift in attitudes towards telepractice as the world adjusts to new norms and endemic COVID-19. AIMS: To compare the speech telepractice use and perspectives of SLTs at two time points of the pandemic: during and after the height of the pandemic. METHODS & PROCEDURES: Two online surveys were distributed a year apart among SLTs in Singapore. The first survey was disseminated during an initial lockdown period in 2020 and the second survey was done in 2021 when Singapore was starting to reduce strict quarantine and safe-distancing regulations. These surveys were distributed via communication channels of the local speech therapy association. A total of 115 and 71 responses to the survey were collected in 2020 and 2021, respectively. Responses were captured and analysed using descriptive statistics and statistical analysis while qualitative content analysis was used to derive key themes from open-ended questions. OUTCOMES & RESULTS: Telepractice use across all age groups and client types peaked at the height of the pandemic. Even as lockdown measures were eased, telepractice utilization was still higher than what it was before the pandemic. Dysphagia management was the only area where SLTs reduced their use of telepractice during the stabilization phase. After more experience with telepractice during the height of the pandemic, SLTs acknowledged the benefit of being able to use a wide range of media through telepractice and were less worried about not having the resources or knowledge to set up telepractice. SLTs also reported increased confidence in providing telepractice, which was reflected in their willingness to continue to provide telepractice even after the pandemic ends. CONCLUSIONS & IMPLICATIONS: The increase in use of telepractice during this pandemic is likely to be sustained as a majority of respondents believed they would continue to provide this mode of service delivery even after the pandemic ends. However, clinicians will still have to assess for client suitability, as clients with more complex medical or behavioural issues may still require in-person therapy. Additionally, dysphagia management via telepractice will still be limited given that swallow presentations may be more variable. Lastly, although generic resources are helpful for clinicians, the long-term sustainability of telepractice can be boosted by the sharing of resources that are suitable for the local context. WHAT THIS PAPER ADDS: What is already known on this subject Current studies have examined telepractice use and perspectives of SLTs before and during the COVID-19 pandemic. Despite the evidence for the efficacy of telepractice, uptake was low due to perceived lack of training and resources. Although more clinicians provided telepractice during the pandemic, many still doubted its efficacy over in-person therapy and most studies concluded that longer term studies are required to ascertain if SLTs will continuing providing telepractice after the pandemic. What this paper adds to existing knowledge This study shows that there is a definitive shift in perspectives in favour of telepractice after the pandemic, as clinicians continued to provide telepractice across most service areas even without lockdown restrictions. The previous challenges of insufficient resources, knowledge and privacy concerns were reduced with more experience in providing telepractice. Although client suitability remained a major barrier, more clinicians saw benefits of easy access to therapy and range of resources used as benefits that they could harness from telepractice. What are the potential or actual clinical implications of this work? A majority of respondents stated that they are more confident in providing telepractice and would want to continue providing this service delivery mode after the pandemic, so more training and resources suitable for the local contexts can be provided by national associations to sustain this. More research and resources can be gathered to make telepractice more efficacious for dysphagia management and clients who may be deemed unsuitable for telepractice.


Assuntos
COVID-19 , Transtornos de Deglutição , Humanos , Terapia da Linguagem/métodos , Pandemias , Fala , Singapura/epidemiologia , COVID-19/epidemiologia , Controle de Doenças Transmissíveis , Fonoterapia/métodos
13.
Int J Mol Sci ; 24(6)2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-36982147

RESUMO

Porcine epidemic diarrhea virus (PEDV) infection results in severe epidemic diarrhea and the death of suckling pigs. Although new knowledge about the pathogenesis of PEDV has been improved, alterations in metabolic processes and the functional regulators involved in PEDV infection with host cells remain largely unknow. To identify cellular metabolites and proteins related to PEDV pathogenesis, we synergistically investigated the metabolome and proteome profiles of PEDV-infected porcine intestinal epithelial cells by liquid chromatography tandem mass spectrometry and isobaric tags for relative and absolute quantification techniques. We identified 522 differential metabolites in positive and negative ion modes and 295 differentially expressed proteins after PEDV infection. Pathways of cysteine and methionine metabolism, glycine, serine and threonine metabolism, and mineral absorption were significantly enriched by differential metabolites and differentially expressed proteins. The betaine-homocysteine S-methyltransferase (BHMT) was indicated as a potential regulator involved in these metabolic processes. We then knocked down the BHMT gene and observed that down-expression of BHMT obviously decreased copy numbers of PEDV and virus titers (p < 0.01). Our findings provide new insights into the metabolic and proteomic profiles in PEDV-infected host cells and contribute to our further understanding of PEDV pathogenesis.


Assuntos
Vírus da Diarreia Epidêmica Suína , Doenças dos Suínos , Animais , Suínos , Vírus da Diarreia Epidêmica Suína/metabolismo , Proteômica/métodos , Células Epiteliais/patologia , Intestinos/patologia , Proteínas/metabolismo
14.
Int J Mol Sci ; 25(1)2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38203339

RESUMO

Ochratoxin A (OTA) is one of the mycotoxins that poses a serious threat to human and animal health. Curcumin (CUR) is a major bioactive component of turmeric that provides multiple health benefits. CUR can reduce the toxicities induced by mycotoxins, but the underlying molecular mechanisms remain largely unknown. To explore the effects of CUR on OTA toxicity and identify the key regulators and metabolites involved in the biological processes, we performed metabolomic and transcriptomic analyses of livers from OTA-exposed mice. We found that CUR can alleviate the toxic effects of OTA on body growth and liver functions. In addition, CUR supplementation significantly affects the expressions of 1584 genes and 97 metabolites. Integrated analyses of transcriptomic and metabolomic data showed that the pathways including Arachidonic acid metabolism, Purine metabolism, and Cholesterol metabolism were significantly enriched. Pantothenic acid (PA) was identified as a key metabolite, the exogenous supplementation of which was observed to significantly alleviate the OTA-induced accumulation of reactive oxygen species and cell apoptosis. Further mechanistical analyses revealed that PA can downregulate the expression level of proapoptotic protein BAX, enhance the expression level of apoptosis inhibitory protein BCL2, and decrease the level of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2). This study demonstrated that CUR can alleviate the adverse effects of OTA by influencing the transcriptomic and metabolomic profiles of livers, which may contribute to the application of CUR in food and feed products for the prevention of OTA toxicity.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Curcumina , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Micotoxinas , Ocratoxinas , Humanos , Animais , Camundongos , Curcumina/farmacologia , Perfilação da Expressão Gênica , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle
15.
Int J Mol Sci ; 24(9)2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37175615

RESUMO

Accumulating evidence suggests the involvement of tumor-derived exosomes in the development and recurrence of hepatocellular carcinoma (HCC). We previously identified miR-4669 as a highly expressed microRNA in circulating exosomes obtained from patients with post-transplant HCC recurrence. This study aimed to explore how overexpression of miR-4669 affects HCC development and recurrence. The impact of miR-4669 overexpression in Hep3B cells on tumor cell behavior and the tumor microenvironment was evaluated in vitro. In addition, the clinical value of exosomal miR-4669 for the prediction of treatment response to HCC downstaging therapies and following post-transplant HCC recurrence was explored. Overexpression of miR-4669 enhanced migration ability and led to acquired sorafenib resistance with an elevation of sirtuin 1 and long noncoding RNA associated with microvascular invasion. Active release of tumor-derived exosomes and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) contributed to generating an immunosuppressive tumor microenvironment through the induction of M2 macrophage polarization. The retrospective analysis demonstrated the clinical value of exosomal miR-4669 for predicting treatment response to HCC downstaging therapies and for risk assessment of post-transplant HCC recurrence. In summary, the present data demonstrate the impact of exosomal miR-4669 on HCC recurrence through the enhancement of tumor aggressiveness and generation of an immunosuppressive tumor microenvironment.


Assuntos
Biomarcadores Tumorais , Carcinoma Hepatocelular , Exossomos , Neoplasias Hepáticas , MicroRNAs , Humanos , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/genética , Exossomos/genética , Exossomos/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/patologia , MicroRNAs/genética , Estudos Retrospectivos , Microambiente Tumoral/genética
16.
Angew Chem Int Ed Engl ; 62(51): e202315189, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-37919233

RESUMO

Thermally triggered spatial symmetry breaking in traditional ferroelectrics has been extensively studied for manipulation of the ferroelectricity. However, photoinduced molecular orbital breaking, which is promising for optical control of ferroelectric polarization, has been rarely explored. Herein, for the first time, we synthesized a homochiral fulgide organic ferroelectric crystal (E)-(R)-3-methyl-3-cyclohexylidene-4-(diphenylmethylene)dihydro-2,5-furandione (1), which exhibits both ferroelectricity and photoisomerization. Significantly, 1 shows a photoinduced reversible change in its molecular orbitals from the 3 π molecular orbitals in the open-ring isomer to 2 π and 1 σ molecular orbitals in the closed-ring isomer, which enables reversible ferroelectric domain switching by optical manipulation. To our knowledge, this is the first report revealing the manipulation of ferroelectric polarization in homochiral ferroelectric crystal by photoinduced breaking of molecular orbitals. This finding sheds light on the exploration of molecular orbital breaking in ferroelectrics for optical manipulation of ferroelectricity.

17.
J Am Chem Soc ; 144(48): 22325-22331, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36426869

RESUMO

Molecular ferroelectrics with large piezoelectric responses have long been sought for their advantages of light weight, mechanical flexibility, and easy preparation, in contrast to the widely used inorganic counterparts. Representatively, a molecular ferroelectric crystal [Me3NCH2Cl]CdCl3 (TMCM-CdCl3) has been found to show a large piezoelectric coefficient d33 of 220 pC/N exceeding that of BaTiO3 (You et al. Science2017, 357, 306-309). However, although the d33 of molecular ferroelectrics has achieved great progress, their electromechanical coupling factor k33, which is essential for various piezoelectric applications, including ultrasonic transducers and actuators, was rarely explored and is far below the level of inorganic ferroelectrics. The major reason for this situation is the great challenge of growing large-size crystals which is a key limiting factor for measuring k33. Here, we grew inch-size crystals of organic-inorganic perovskite ferroelectric TMCM-CdCl3 with a high d33 (383 pC/N) for investigating its piezoelectric responses including the k33 (0.483) by the resonance method. Such high k33 (0.483) is much larger than those of other molecular ferroelectrics and competitive with that of BaTiO3 (0.5). In addition, TMCM-CdCl3 has a low elastic modulus of 13.03 GPa, an order of magnitude lower than that of BaTiO3. This finding sheds light on the exploration of large electromechanical coupling factors in molecular ferroelectrics for potential applications in flexible and portable piezoelectric devices.

18.
J Neuroinflammation ; 19(1): 149, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35705998

RESUMO

BACKGROUND: The emergence of the novel, pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global health emergency. SARS-CoV-2 is highly contagious and has a high mortality rate in severe patients. However, there is very limited information on the effect of SARS-CoV-2 infection on the integrity of the blood-brain barrier (BBB). METHODS: RNA-sequencing profiling was performed to analyze the transcriptomic changes in human brain microvascular endothelial cells (hBMECs) after SARS-CoV-2 infection. Bioinformatic tools were used for differential analysis. Immunofluorescence, real-time quantitative PCR, and Western blotting analysis were used to explore biological phenotypes. RESULTS: A total of 927 differentially expressed genes were identified, 610 of which were significantly upregulated while the remaining 317 were downregulated. We verified the significant induction of cytokines, chemokines, and adhesion molecules in hBMECs by SARS-CoV-2, suggesting an activation of the vascular endothelium in brain. Moreover, we demonstrated that SARS-CoV-2 infection could increase the BBB permeability, by downregulating as well as remodeling the intercellular tight junction proteins. CONCLUSIONS: Our findings demonstrated that SARS-CoV-2 infection can cause BBB dysfunction, providing novel insights into the understanding of SARS-CoV-2 neuropathogenesis. Moreover, this finding shall constitute a new approach for future prevention and treatment of SARS-CoV-2-induced CNS infection.


Assuntos
COVID-19 , SARS-CoV-2 , Barreira Hematoencefálica/metabolismo , Encéfalo , Células Endoteliais , Humanos
19.
BMC Neurosci ; 23(1): 43, 2022 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-35794518

RESUMO

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious, and the neurological symptoms of SARS-CoV-2 infection have already been reported. However, the mechanisms underlying the effect of SARS-CoV-2 infection on patients with central nervous system injuries remain unclear. METHODS: The high-throughput RNA sequencing was applied to analyze the transcriptomic changes in SK-N-SH cells after SARS-CoV-2 infection. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to identify the functions of differentially expressed genes and related pathways. RESULTS: A total of 820 mRNAs were significantly altered, including 671 upregulated and 149 downregulated mRNAs (showing an increase of ≥ 2-fold or decrease to ≤ 0.5-fold, respectively; p ≤ 0.05). Moreover, we verified the significant induction of cytokines, chemokines, and their receptors, as well as the activation of NF-κB, p38, and Akt signaling pathways, in SK-N-SH by SARS-CoV-2. CONCLUSIONS: To our knowledge, this is the first time the transcriptional profiles of the host mRNAs involved in SARS-CoV-2 infection of SK-N-SH cells have been reported. These findings provide novel insight into the pathogenic mechanism of SARS-CoV-2 and might constitute a new approach for future prevention and treatment of SARS-CoV-2-induced central nervous system infection.


Assuntos
COVID-19 , Neuroblastoma , Citocinas , Humanos , NF-kappa B , RNA Mensageiro/metabolismo , SARS-CoV-2
20.
Blood ; 136(18): 2038-2050, 2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-32731259

RESUMO

Bruton tyrosine kinase (BTK) inhibition is an effective treatment approach for patients with Waldenström macroglobulinemia (WM). The phase 3 ASPEN study compared the efficacy and safety of ibrutinib, a first-generation BTK inhibitor, with zanubrutinib, a novel highly selective BTK inhibitor, in patients with WM. Patients with MYD88L265P disease were randomly assigned 1:1 to treatment with ibrutinib or zanubrutinib. The primary end point was the proportion of patients achieving a complete response (CR) or a very good partial response (VGPR) by independent review. Key secondary end points included major response rate (MRR), progression-free survival (PFS), duration of response (DOR), disease burden, and safety. A total of 201 patients were randomized, and 199 received ≥1 dose of study treatment. No patient achieved a CR. Twenty-nine (28%) zanubrutinib patients and 19 (19%) ibrutinib patients achieved a VGPR, a nonstatistically significant difference (P = .09). MRRs were 77% and 78%, respectively. Median DOR and PFS were not reached; 84% and 85% of ibrutinib and zanubrutinib patients were progression free at 18 months. Atrial fibrillation, contusion, diarrhea, peripheral edema, hemorrhage, muscle spasms, and pneumonia, as well as adverse events leading to treatment discontinuation, were less common among zanubrutinib recipients. Incidence of neutropenia was higher with zanubrutinib, although grade ≥3 infection rates were similar in both arms (1.2 and 1.1 events per 100 person-months). These results demonstrate that zanubrutinib and ibrutinib are highly effective in the treatment of WM, but zanubrutinib treatment was associated with a trend toward better response quality and less toxicity, particularly cardiovascular toxicity.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Macroglobulinemia de Waldenstrom/tratamento farmacológico , Adenina/administração & dosagem , Adenina/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Piperidinas/administração & dosagem , Prognóstico , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagem , Taxa de Sobrevida , Macroglobulinemia de Waldenstrom/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA