Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 64
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Nucleic Acids Res ; 52(6): 3406-3418, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38412313

RESUMO

RNA helicases function as versatile enzymes primarily responsible for remodeling RNA secondary structures and organizing ribonucleoprotein complexes. In our study, we conducted a systematic analysis of the helicase-related activities of Escherichia coli HrpA and presented the structures of both its apo form and its complex bound with both conventional and non-canonical DNAs. Our findings reveal that HrpA exhibits NTP hydrolysis activity and binds to ssDNA and ssRNA in distinct sequence-dependent manners. While the helicase core plays an essential role in unwinding RNA/RNA and RNA/DNA duplexes, the N-terminal extension in HrpA, consisting of three helices referred to as the APHB domain, is crucial for ssDNA binding and RNA/DNA duplex unwinding. Importantly, the APHB domain is implicated in binding to non-canonical DNA structures such as G-quadruplex and i-motif, and this report presents the first solved i-motif-helicase complex. This research not only provides comprehensive insights into the multifaceted roles of HrpA as an RNA helicase but also establishes a foundation for further investigations into the recognition and functional implications of i-motif DNA structures in various biological processes.


Assuntos
DNA Helicases , Proteínas de Escherichia coli , Sequência de Aminoácidos , DNA/química , DNA Helicases/metabolismo , DNA de Cadeia Simples/genética , Escherichia coli/metabolismo , RNA/química , RNA Helicases/genética , Proteínas de Escherichia coli/metabolismo
2.
Environ Sci Technol ; 58(1): 121-131, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38118121

RESUMO

The COVID-19 pandemic has resulted in huge amounts of face masks worldwide. However, there is a lack of awareness on the additives and their potential risk to aquatic ecosystems of face masks. To address this issue, the additives and their toxicity in 13 face masks (e.g., polypropylene, polyethylene, and polylactic acid) were determined using nontarget analysis and bioassays. A total of 826 organic additives including intermediates (14.8%), surfactants (9.3%), plasticizers (8.2%), and antioxidants (6.1%) were tentatively identified, with 213 compounds being assigned confidence levels of 1 and 2. Interestingly, polylactic acid masks contained more additives than most polypropylene or polyethylene masks. Among these additives, the concentration of tris(2-ethylhexyl) phosphate in masks was 9.4-978.2 ng/g with a 100% detection frequency. Furthermore, 13 metals such as zinc (up to 202.0 µg/g), copper (32.5 µg/g), and chromium (up to 5.7 µg/g) were detected in the face masks. The methanol extracts of the masks showed the developmental toxicity, swimming behavior, and/or endocrine disruption in embryos/larvae of Oryzias melastigma. The findings demonstrate that face masks contain various toxic additives to marine medaka, which deserves close attention to pollution by face masks.


Assuntos
Oryzias , Poluentes Químicos da Água , Animais , Humanos , Ecossistema , Máscaras , Pandemias , Polipropilenos , Polietilenos
3.
Environ Sci Technol ; 57(8): 3280-3290, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36795899

RESUMO

Bisphenol 4-[1-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexyl] phenol (BPTMC), as a substitute for bisphenol A, has been detected in environments. However, the ecotoxicological data of BPTMC are extremely scarce. Here, the lethality, developmental toxicity, locomotor behavior, and estrogenic activity of BPTMC at different concentrations (0.25-2000 µg/L) in marine medaka (Oryzias melastigma) embryos were examined. In addition, the in silico binding potentials of O. melastigma estrogen receptors (omEsrs) with BPTMC were assessed by docking study. Low-concentration BPTMC exposure (including an environmentally relevant concentration, 0.25 µg/L) resulted in stimulating effects, including hatching rate, heart rate, malformation rate, and swimming velocity. However, elevated concentrations of BPTMC led to an inflammatory response, changed heart rate and swimming velocity in the embryos and larvae. In the meantime, BPTMC (including 0.25 µg/L) altered the concentrations of estrogen receptor, vitellogenin, and endogenous 17 ß-estradiol as well as the transcriptional levels of estrogen-responsive genes in the embryos or/and larvae. Furthermore, elaborate tertiary structures of omEsrs were built by ab initio modeling, and BPTMC exerted potent binding potential with three omEsrs with -47.23, -49.23, and -50.30 kJ/mol for Esr1, Esr2a, and Esr2b, respectively. This work suggests that BPTMC has potent toxicity and estrogenic effects in O. melastigma.


Assuntos
Oryzias , Poluentes Químicos da Água , Animais , Oryzias/fisiologia , Estrona/metabolismo , Estrogênios/metabolismo , Fenóis/toxicidade , Receptores de Estrogênio/metabolismo , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/metabolismo
4.
J Craniofac Surg ; 34(2): 805-808, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36729378

RESUMO

INTRODUCTION: In recent years, 3-dimensional (3D) printing has been widely used in regenerative medicine research and other fields because of its ability to customize macroscopic morphology and precisely control microstructure. Polymer scaffolds are 1 of the commonly used 3D bioprinting materials for defect repair and have recently been a research focus. Our article explored the bone-formation accelerating effect of 3D-printed porous scaffold Poly(glycerol sebacate) [PGS] in the critical bone defect of an enhancing rabbit mandibular model. Also, we overview and summarize the classification of 3D bioprinting materials and prospects for their various application scenarios in craniofacial reconstruction surgery. MATERIALS AND METHODS: A PGS elastomer scaffold was prepared by polymerizing equimolar amounts of sebacic acid and glycerol using a biological 3D printer. Six male New Zealand white rabbits were prepared (3 for the control group and 3 for the PGS group), each weighing 3 kg. Osteotomy was performed at the anterior edge of the ascending ramus of the mandible with a bone saw to open the 8 mm defect. Defects of the control group were empty, and defects of the PGS group were put into 8 mm-wide PGS elastomer scaffolds. The rabbits were euthanized 6 weeks after the operation, and the postoperative mandibles were collected. Information (presence or absence of pus from infection, nonunion, degree of macroscopic bone healing) was recorded, and the skeletal tissue was fixed in a paraformaldehyde solution. RESULTS: The mandible on the enhanced side was significantly longer than that on the opposite side, and the contralateral incisor was hyperplasia. The mandibles of rabbits in each group healed well, and there was no obvious local infection and purulence. The gross specimen appearance showed that both ends of the defect were connected. When comparing the reconstructed mandibles of the two groups, it is apparent that the width and thickness of the new bone in the PGS group were significantly better than that in the control group. CONCLUSIONS: This article verifies the effect of 3D polypore PGS scaffolds in animal craniomaxillofacial bone defects and introduces various application scenarios of 3D printing materials in craniomaxillofacial reconstruction surgery. There are quite good application prospects for 3D bioprinting in animal experiments and even clinical treatment of craniofacial defects.


Assuntos
Bioimpressão , Alicerces Teciduais , Masculino , Coelhos , Animais , Alicerces Teciduais/química , Osteogênese , Mandíbula , Elastômeros , Impressão Tridimensional , Engenharia Tecidual
5.
Eur J Anaesthesiol ; 39(11): 858-867, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36106493

RESUMO

BACKGROUND: Emergence agitation is a common paediatric complication after inhalational anaesthesia. Intranasal dexmedetomidine can prevent emergence agitation effectively, but the optimal dose is uncertain. OBJECTIVE: The aim of our study was to investigate the 95% effective dose (ED 95 ) of intranasal dexmedetomidine for the prevention of emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery. DESIGN: A prospective, randomised, placebo-controlled, double-blind, clinical trial. SETTING: The study was conducted in Guangzhou Women and Children's Medical Center in China from August 2017 to December 2018. PATIENTS: Three hundred and eighteen children scheduled for ambulatory surgery were enrolled into two age groups of less than 3 years and at least 3 years. INTERVENTIONS: The children in each age group were randomised into five equal subgroups to receive either intranasal dexmedetomidine 0.5, 1.0, 1.5 or 2.0 µg kg -1 (Groups D 0.5 , D 1.0 , D 1.5 and D 2.0 ), or intranasal isotonic saline (group C) after induction. MAIN OUTCOME MEASURES: The primary outcome was the ED 95 dose of intranasal dexmedetomidine for preventing emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery. RESULTS: The incidences of emergence agitation for Groups C, D 0.5 , D 1.0 , D 1.5 and D 2.0 were 63, 40, 23, 13 and 3% in children less than 3 years, and 43, 27, 17, 7 and 3% in children at least 3 years. The ED 95 of intranasal dexmedetomidine for preventing emergence agitation was 1.99 µg kg -1 [95% confidence interval (CI), 1.83 to 3.80 µg kg -1 ] in children less than 3 years, and 1.78  µg kg -1 (95% CI, 0.93 to 4.29 µg kg -1 ) in children at least 3 years. LMA removal time for groups D 1.5 and D 2.0 was 9.6 ±â€Š2.2 and 9.7 ±â€Š2.5 min, respectively, for children less than 3 years, and 9.4 ±â€Š2.0 and 9.9 ±â€Š2.7 min in children at least 3 years, respectively. Length of stay in the postanaesthesia care unit for Groups D 1.5 and D 2.0 was 34.3 ±â€Š9.6 and 37.1 ±â€Š11.2 min, respectively, in children less than 3 years, and 34.7 ±â€Š10.2 and 37.3 ±â€Š8.3 min in children at least 3 years, respectively. These times were longer in the D 1.5 and D 2.0 subgroups than in the control subgroup in the two age groups of less than 3 years and at least 3 years, respectively: 7.2 ±â€Š1.9 min in children less than 3 years and 7.3 ±â€Š2.5 min in children at least 3 years for LMA removal time, 22.2 ±â€Š7.9 min in children less than 3 years and 22.0 ±â€Š7.7 min in children at least 3 years for PACU stay time in control subgroup, respectively ( P  < 0.05). CONCLUSION: Intranasal dexmedetomidine prevented emergence agitation after paediatric surgery in a dose-dependent manner. The optimal dose of intranasal dexmedetomidine for preventing emergence agitation was higher in younger children. TRIAL REGISTRY: chictr.org.cn: ChiCTR-IOR-17012415.


Assuntos
Anestésicos Inalatórios , Dexmedetomidina , Delírio do Despertar , Anestesia por Inalação/efeitos adversos , Anestésicos Inalatórios/efeitos adversos , Criança , Pré-Escolar , Dexmedetomidina/efeitos adversos , Método Duplo-Cego , Delírio do Despertar/diagnóstico , Delírio do Despertar/epidemiologia , Delírio do Despertar/etiologia , Feminino , Humanos , Hipnóticos e Sedativos/uso terapêutico , Estudos Prospectivos , Agitação Psicomotora/diagnóstico , Agitação Psicomotora/epidemiologia , Agitação Psicomotora/etiologia
6.
Zhongguo Zhong Yao Za Zhi ; 47(8): 2109-2120, 2022 Apr.
Artigo em Zh | MEDLINE | ID: mdl-35531727

RESUMO

The chemical constituents of classical prescription Danggui Buxue Decoction were analyzed by reversed-phase(RP) chromatography and hydrophilic interaction chromatography(HILIC) coupled with quadrupole time-of-flight mass spectrometry. RP separation of Danggui Buxue Decoction was performed on ACQUITY UPLC HSS T3(2.1 mm×100 mm, 1.8 µm), while HILIC separation was on Waters BEH Amide(2.1 mm×100 mm, 1.7 µm). Mass spectrometry(MS) data were acquired in both negative and positive ion modes. Chemical constituents of Astragali Radix and Angelicae Sinensis Radix were searched from Reaxys and thus the in-house library was established. MS data were further analyzed by MassLynx 4.1 combined with in-house library, HMDB, Reaxys, and comparison with reference substances. In conclusion, a total of 154 compounds were identified and characterized: 16 saponins, 44 flavonoids, 10 phthalides, 7 phenylpropanoids, 15 bases and the corresponding nucleosides, 30 oligosaccharides, and 32 other compounds. Among them, 65 compounds were detected by HILIC-MS/MS. This study provides experimental evidences for the material basis research, quality control, and preparation development of Danggui Buxue Decoction and a reference method for comprehensive characterization of Chinese medicine decoctions typified by classical prescriptions.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Prescrições
7.
BMC Anesthesiol ; 21(1): 298, 2021 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-34847868

RESUMO

BACKGROUND: The spread of spinal anesthesia was influenced by many factors, and the effect of body height on spinal anesthesia is still arguable. This study aimed to explore the impact of height on the spread of spinal anesthesia and the stress response in parturients. METHODS: A total of ninety-seven parturients were allocated into two groups according to their height: the shorter group (body height was shorter than 158 cm) and taller group (body height was taller than 165 cm). Spinal anesthesia was performed with the same amount of 12 mg plain ropivacaine in mothers of different heights. The primary outcome of the study was the success or failure of the spinal anesthesia. The secondary outcomes of the study were stress response, time to T6 sensory level, the incidence of hypotension, the satisfaction of abdominal muscle relaxation and patient VAS scores. RESULTS: The rate of successful spinal anesthesia in the shorter group was significantly higher than that in the taller group (p = 0.02). The increase of maternal cortisol level in the shorter group was lower than that in the taller group at skin closure (p = 0.001). The incidence of hypotension (p = 0.013), time to T6 sensory block (p = 0.005), the quality of abdominal muscle relaxation (p <  0.001), and VAS values in stretching abdominal muscles and uterine exteriorization (p <  0.001) in the shorter group were significantly different from those in the taller group. Multivariate analysis showed that vertebral column length (p <  0.001), abdominal girth (p = 0.022), amniotic fluid index (p = 0.022) were significantly associated with successful spinal anesthesia. CONCLUSIONS: It's difficult to use a single factor to predict the spread of spinal anesthesia. Patient's vertebral column length, amniotic fluid index and abdominal girth were the high determinant factors for predicting the spread of spinal anesthesia. TRIALS REGISTRATION: ChiCTR-ROC-17012030 ( Chictr.org.cn ), registered on 18/07/2017.


Assuntos
Anestesia Obstétrica/métodos , Raquianestesia/métodos , Estatura , Cesárea , Ropivacaina/farmacocinética , Estresse Fisiológico/efeitos dos fármacos , Adulto , Anestésicos Locais/farmacocinética , Feminino , Humanos , Estudos Prospectivos
8.
Appl Opt ; 59(34): 10813-10825, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33361902

RESUMO

A conventional optical extensometer realized by a single common camera and two-dimensional digital image correlation (2D-DIC) often provides unsatisfactory strain results owing to the out-of-plane motion of the specimen. In this work, we propose an improved optical extensometer based on two parallel cameras and 2D-DIC. In the proposed extensometer, the gauge points are selected at the image centers of two cameras, which are negligibly affected by the out-of-plane translation and rotation, leading to higher accuracy of strain measurement as compared with the conventional optical extensometer. A rigid out-of-plane translation experiment and four repeated uniaxial tensile tests were conducted to verify the feasibility, reliability, and accuracy of the proposed method. Experimental results indicate that the proposed method has a strong ability to resist the effect of out-of-plane motion and experimental vibrations. Moreover, the strain measurement results obtained with the proposed method were found to be in excellent agreement with those obtained with a strain gauge, and the strain errors between them were only a few microstrains. Given that no compensation method is required, the proposed method is easy to implement with 2D-DIC and can be used for specimens of different sizes by adjusting the distance between the two cameras.

9.
J Cell Mol Med ; 19(10): 2462-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26249143

RESUMO

Liver fibrosis is characterized by an exacerbated accumulation of deposition of the extracellular matrix (ECM), and the activation of hepatic stellate cells (HSC) plays a pivotal role in the development of liver fibrosis. Periostin has been shown to regulate cell adhesion, proliferation, migration and apoptosis; however, the involvement of periostin and its role in transforming growth factor (TGF)-ß1-induced HSC activation remains unclear. We used RT-PCR and Western blot to evaluate the expression level of periostin in hepatic fibrosis tissues and HSCs, respectively. Cell proliferation was determined using the Cell Proliferation ELISA BrdU kit, cell cycle was analysed by flow cytometry. The expression of α-smooth muscle actin (α-SMA), collagen I, TGF-ß1, p-Smad2 and p-Smad3 were determined by western blot. Our study found that periostin was up-regulated in liver fibrotic tissues and activated HSCs. In addition, siRNA-periostin suppressed TGF-ß1-induced HSC proliferation. The HSC transfected with siRNA-periostin significantly inhibited TGF-ß1-induced expression levels of α-SMA and collagen I. Furthermore, TGF-ß1 stimulated the expression of periostin, and siRNA-periostin attenuated TGF-ß1-induced Smad2/3 activation in HSCs. These results suggest that periostin may function as a novel regulator to modulate HSC activation, potentially by promoting the TGF-ß1/Smad signalling pathway, and propose a strategy to target periostin for the treatment of liver fibrosis.


Assuntos
Moléculas de Adesão Celular/metabolismo , Regulação para Baixo , Células Estreladas do Fígado/metabolismo , Cirrose Hepática/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Actinas/metabolismo , Ciclo Celular , Proliferação de Células , Colágeno Tipo I/metabolismo , Humanos , Cirrose Hepática/patologia , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Regulação para Cima/efeitos dos fármacos
10.
Mol Cell Biochem ; 391(1-2): 117-25, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24526524

RESUMO

The development of atherosclerosis (AS) is a multifactorial process, in which elevated plasma resistin (a key factor leading to insulin resistance) levels play an important role. Emerging evidence indicate that microRNAs (miRNAs) are involved in AS; However, the regulation and function of miRNAs in response to AS remain poorly understood. Our study analyzed the effects of miR-492 on insulin resistance, endothelial activation, and resistin expression in apoE knock-out mice and human umbilical vein endothelial cells after high-glucose treatment and miR-492 mimics transfection. We also investigated the underlying molecular mechanisms. Our results showed that high glucose stress induced a significant decrease in miR-492 expression, with a remarkable upregulation of resistin expression. We then identified resistin as a novel direct target of miR-492 using 3'-UTR luciferase reporter assay. Histopathologic examination demonstrated that upregulation of miR-492 attenuated endothelial cells migration and lipid accumulation induced by high glucose stress. Further investigation demonstrated that the upregulation of p-STAT3, SOCS, and P-selectin activation induced by high glucose stress was attenuated by upregulation of miR-492. Together, our findings indicate that miR-492 contributes to insulin resistance and endothelial dysfunction induced by high glucose, via directly downregulating resistin expression, and involving STAT3 phosphorylation, SOCS, and P-selectin activation.


Assuntos
Glucose/farmacologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Resistência à Insulina/genética , MicroRNAs/metabolismo , Resistina/metabolismo , Regiões 3' não Traduzidas/genética , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Apolipoproteínas E/deficiência , Apolipoproteínas E/metabolismo , Sequência de Bases , Regulação da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Insulina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Dados de Sequência Molecular , Ligação Proteica/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Resistina/genética
11.
Front Psychol ; 15: 1443516, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39359957

RESUMO

Objective: This study aims to assess the effect of mindfulness intervention on negative emotions (anxiety and depression) and quality of life in malignant tumor patients. Methods: The databases, including CNKI, VIP, Wanfang, Chinese Biomedical Literature Database disc (CBMdisc), PubMed, Embase, Cochrane Library, and Web of Science (WoS), were searched from inception to January 2024. Randomized controlled trials examining the effects of mindfulness intervention on negative emotions and quality of life in malignant tumor patients were selected. Meta-analysis was conducted using RevMan 5.1. Results: A total of 11 studies involving 993 patients were included. Compared with usual care, mindfulness intervention effectively reduced anxiety [SMD = -0.81, 95% CI (-1.01, -0.60), p < 0.00001], depression [SMD = -0.86, 95% CI (-1.01, -0.70), p < 0.00001], and improved patients' quality of life [SMD = 0.64, 95% CI (0.50, 0.78), p < 0.00001]. Conclusion: Mindfulness intervention can effectively alleviate negative emotions such as anxiety and depression in malignant tumor patients and positively impact their quality of life.

12.
Environ Int ; 191: 108949, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39213921

RESUMO

Ageing is a nature process of microplastics that occurrs daily, and human beings are inevitably exposed to aged microplastics. However, a systematic understanding of ageing status and its toxic effect is currently still lacking. In this study, plastic cup lids-originated polypropylene (PP) microplastics were UV-photoaged until the carbonyl index (CI), a canonical indicator for plastic ageing, achieved 0.08, 0.17, 0.22 and 0.28. The adverse hepatic effect of these aged PPs (aPPs) was evaluated in Balb/c mice (75 ng/mL water, about 200 particles/day) and human-originated liver organoids (LOs, 50 particles/mL, ranged from 5.94 to 13.15 ng/mL) at low-dose equivalent to human exposure level. Low-dose of aged PP could induce hepatic reductive stress both in vitro and in vivo, by elevating the NADH/NAD+ratio in a CI-dependent manner, together with hepatoxicity (indicated by increased AST secretion and cytotoxicity), and disrupted the genes encoding the nutrients transporters and NADH subunits accompanied by the restricted ATP supply, declined mitochondrial membrane potential and mitochondrial complexI/IV activities, without significant increase in MDA levels in the liver. These changes in the liver disrupted systematic metabolism, representing a circulatory panel of increases in the lactate, triglyceride, Fgf21 levels, and decreases in the pyruvate level, linked the reductive stress to the declined body weight gain but elevated hepatic NADH contents following aPPs exposure. Additionally, assessing by the LOs, it was found that digestion drastically accelerated the ageing of aPPs and worsen the energy supply upon mitochondria, representing a "scattergun effect" induced by the formation of micro- and nano-plastics mixture toward NADH/NAD+imbalance.


Assuntos
Fígado , Camundongos Endogâmicos BALB C , Microplásticos , Organoides , Polipropilenos , Animais , Fígado/efeitos dos fármacos , Fígado/metabolismo , Microplásticos/toxicidade , Camundongos , Organoides/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Humanos , Masculino
13.
Adv Sci (Weinh) ; 11(39): e2405420, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39159156

RESUMO

Functional segmental trachea reconstruction is a critical concern in thoracic surgery, and tissue-engineered trachea (TET) holds promise as a potential solution. However, current TET falls short in fully restoring physiological function due to the lack of the intricate multi-tissue structure found in natural trachea. In this research, a multi-tissue integrated tissue-engineered trachea (MI-TET) is successfully developed by orderly assembling various cells (chondrocytes, fibroblasts and epithelial cells) on 3D-printed PGS bioelastomer scaffolds. The MI-TET closely resembles the complex structures of natural trachea and achieves the integrated regeneration of four essential tracheal components: C-shaped cartilage ring, O-shaped vascularized fiber ring, axial fiber bundle, and airway epithelium. Overall, the MI-TET demonstrates highly similar multi-tissue structures and physiological functions to natural trachea, showing promise for future clinical advancements in functional TETs.


Assuntos
Impressão Tridimensional , Regeneração , Engenharia Tecidual , Alicerces Teciduais , Traqueia , Traqueia/cirurgia , Traqueia/fisiologia , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Regeneração/fisiologia , Animais , Humanos
14.
Bioact Mater ; 39: 443-455, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38873087

RESUMO

The biomedical application of self-healing materials in wet or (under)water environments is quite challenging because the insulation and dissociation effects of water molecules significantly reduce the reconstruction of material-interface interactions. Rapid closure with uniform tension of high-tension wounds is often difficult, leading to further deterioration and scarring. Herein, a new type of thermosetting water-resistant self-healing bioelastomer (WRSHE) was designed by synergistically incorporating a stable polyglycerol sebacate (PGS) covalent crosslinking network and triple hybrid dynamic networks consisting of reversible disulfide metathesis (SS), and dimethylglyoxime urethane (Dou) and hydrogen bonds. And a resveratrol-loaded WRSHE (Res@WRSHE) was developed by a swelling, absorption, and crosslinked network locking strategy. WRSHEs exhibited skin-like mechanical properties in terms of nonlinear modulus behavior, biomimetic softness, high stretchability, and good elasticity, and they also achieved ultrafast and highly efficient self-healing in various liquid environments. For wound-healing applications of high-tension full-thickness skin defects, the convenient surface assembly by self-healing of WRSHEs provides uniform contraction stress to facilitate tight closure. Moreover, Res@WRSHEs gradually release resveratrol, which helps inflammatory response reduction, promotes blood vessel regeneration, and accelerates wound repair.

15.
Biomater Adv ; 163: 213950, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38972278

RESUMO

Traditional tendon engineering using cell-loaded scaffold has limited application potential due to the need of autologous cells. We hypothesize that potent mechanical loading can efficiently induce in situ Achilles tendon regeneration in a rabbit model by using a cell-free porous composite scaffold. In this study, melt-spinning was used to fabricate PGA (polyglycolic acid) and PLA (polylactic acid) filament fibers as well as non-woven PGA fibers. The PLA/PGA (4:2) filament fibers were further braided into a hybrid yarn,which was knitted into a PLA/PGA tubular mesh with potent mechanical property for sustaining natural tendon strain. The results showed that a complete cross-section of Achilles tendon created a model of full mechanical loading on the bridging scaffold, which could efficiently induce in situ tendon regeneration by promoting host cell infiltration, matrix production and tissue remodeling. Histologically, mechanical loading assisted in forming parallel aligned collagen fibers and tenocytes in a fashion similar to those of native tendon. Transmission electron microscope further demonstrated that mechanical strain induced collagen fibril development by increasing fibril diameter and forming bipolar structure, which resulted in enhanced mechanical properties. Interestingly, the synergistic effect between mechanical loading and hyaluronic acid modification was also observed on the induced tenogenic differentiation of infiltrated host fibroblasts. In conclusion, potent mechanical loading is the key inductive microenvironment for in situ tendon regeneration for this polymer-based composite scaffold with proper matrix modification, which may serve as a universal scaffold product for tendon regeneration.


Assuntos
Tendão do Calcâneo , Poliésteres , Regeneração , Engenharia Tecidual , Alicerces Teciduais , Animais , Coelhos , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Poliésteres/química , Tenócitos , Polímeros/química , Materiais Biocompatíveis/química , Estresse Mecânico
16.
Nat Plants ; 10(5): 743-748, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38600265

RESUMO

NARROW LEAF1 (NAL1) exerts a multifaceted influence on leaf morphology and crop yield. Recent crystal study proposed that histidine 233 (H233) is part of the catalytic triad. Here we report that unlike suggested previously, H234 instead of H233 is a component of the catalytic triad alongside residues D291 and S385 in NAL1. Remarkably, residue 233 unexpectedly plays a pivotal role in regulating NAL1's proteolytic activity. These findings establish a strong foundation for utilizing NAL1 in breeding programs aimed at improving crop yield.


Assuntos
Oryza , Proteínas de Plantas , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Folhas de Planta/metabolismo , Folhas de Planta/genética , Histidina/metabolismo
17.
Adv Mater ; 36(27): e2401009, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38548296

RESUMO

Tissue engineering and electrotherapy are two promising methods to promote tissue repair. However, their integration remains an underexplored area, because their requirements on devices are usually distinct. Triboelectric nanogenerators (TENGs) have shown great potential to develop self-powered devices. However, due to their susceptibility to moisture, TENGs have to be encapsulated in vivo. Therefore, existing TENGs cannot be employed as tissue engineering scaffolds, which require direct interaction with surrounding cells. Here, the concept of triboelectric scaffolds (TESs) is proposed. Poly(glycerol sebacate), a biodegradable and relatively hydrophobic elastomer, is selected as the matrix of TESs. Each hydrophobic micropore in multi-hierarchical porous TESs efficiently serves as a moisture-resistant working unit of TENGs. Integration of tons of micropores ensures the electrotherapy ability of TESs in vivo without encapsulation. Originally hydrophobic TESs are degraded by surface erosion and transformed into hydrophilic surfaces, facilitating their role as tissue engineering scaffolds. Notably, TESs seeded with chondrocytes obtain dense and large matured cartilages after subcutaneous implantation in nude mice. Importantly, rabbits with osteochondral defects receiving TES implantation show favorable hyaline cartilage regeneration and complete cartilage healing. This work provides a promising electronic biomedical device and will inspire a series of new in vivo applications.


Assuntos
Decanoatos , Interações Hidrofóbicas e Hidrofílicas , Polímeros , Regeneração , Engenharia Tecidual , Alicerces Teciduais , Alicerces Teciduais/química , Animais , Porosidade , Coelhos , Engenharia Tecidual/métodos , Decanoatos/química , Polímeros/química , Camundongos , Glicerol/química , Glicerol/análogos & derivados , Cartilagem/fisiologia , Condrócitos/citologia , Camundongos Nus , Materiais Biocompatíveis/química
18.
Appl Opt ; 52(32): 7718-23, 2013 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-24216730

RESUMO

A mathematical description of the absolute surface height distribution in generalized fringe projection profilometry under large measuring depth range is presented. Based on least-squares polynomial fitting, a nonlinear calibration to determine the mapping between phase change and surface height is proposed by considering the unequal height arrangement of the projector and the camera. To solve surface height from phase change, an iteration method is brought forward. Experiments are implemented to demonstrate the validity of the proposed calibration and an accuracy of 0.3 mm for surface profile under 300 mm measuring depth can be achieved.

19.
APL Bioeng ; 7(3): 036105, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37547670

RESUMO

Regenerative cartilage replacements are increasingly required in clinical settings for various defect repairs, including bronchial cartilage deficiency, articular cartilage injury, and microtia reconstruction. Poly (glycerol sebacate) (PGS) is a widely used bioelastomer that has been developed for various regenerative medicine applications because of its excellent elasticity, biodegradability, and biocompatibility. However, because of inadequate active groups, strong hydrophobicity, and limited ink extrusion accuracy, 3D printed PGS scaffolds may cause insufficient bioactivity, inefficient cell inoculation, and inconsistent cellular composition, which seriously hinders its further cartilage regenerative application. Here, we combined 3D printed PGS frameworks with an encapsulated gelatin hydrogel to fabricate a PGS@Gel composite scaffold. PGS@Gel scaffolds have a controllable porous microstructure, with suitable pore sizes and enhanced hydrophilia, which could significantly promote the cells' penetration and adhesion for efficient chondrocyte inoculation. Furthermore, the outstanding elasticity and fatigue durability of the PGS framework enabled the regenerated cartilage built by the PGS@Gel scaffolds to resist the dynamic in vivo environment and maintain its original morphology. Importantly, PGS@Gel scaffolds increased the rate of cartilage regeneration concurrent with scaffold degradation. The scaffold was gradually degraded and integrated to form uniform, dense, and mature regenerated cartilage tissue with little scaffold residue.

20.
Gels ; 9(6)2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37367126

RESUMO

Noncompressible wounds resulting from accidents and gunshots are typically associated with excessive bleeding, slow wound healing, and bacterial infection. Shape-memory cryogel presents great potential in controlling the hemorrhaging of noncompressible wounds. In this research, a shape-memory cryogel was prepared using a Schiff base reaction between alkylated chitosan (AC) and oxidized dextran (ODex) and then incorporated with a drug-laden and silver-doped mesoporous bioactive glass (MBG). Hydrophobic alkyl chains enhanced the hemostatic and antimicrobial efficiency of the chitosan, forming blood clots in the anticoagulated condition, and expanding the application scenarios of chitosan-based hemostats. The silver-doped MBG activated the endogenous coagulation pathway by releasing Ca2+ and prevented infection through the release of Ag+. In addition, the proangiogenic desferrioxamine (DFO) in the mesopores of the MBG was released gradually to promote wound healing. We demonstrated that AC/ODex/Ag-MBG DFO(AOM) cryogels exhibited excellent blood absorption capability, facilitating rapid shape recovery. It provided a higher hemostatic capacity in normal and heparin-treated rat-liver perforation-wound models than gelatin sponges and gauze. The AOM gels simultaneously promoted infiltration, angiogenesis, and tissue integration of liver parenchymal cells. Furthermore, the composite cryogel exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli. Thus, AOM gels show great promise for clinical translation in treating lethal, noncompressible bleeding and the promotion of wound healing.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA