Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.546
Filtrar
1.
Am Heart J ; 243: 77-86, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34529944

RESUMO

BACKGROUND: Regulatory agencies have endorsed more limited approaches to clinical trial site monitoring. However, the impact of different monitoring strategies on trial conduct and outcomes is unclear. METHODS: We conducted a patient-level block-randomized controlled trial evaluating the effect of intensive versus limited monitoring on cardiovascular clinical trial conduct and outcomes nested within the CoreValve Continued Access and Expanded Use Studies. Intensive monitoring included complete source data verification of all critical datapoints whereas limited monitoring included automated data checks only. This study's endpoints included clinical trial outcome ascertainment as well as monitoring action items, protocol deviations, and adverse event ascertainment. RESULTS: A total of 2,708 patients underwent transcatheter aortic valve replacement (TAVR) and were randomized to either intensive monitoring (n = 1,354) or limited monitoring (n = 1,354). Monitoring action items were more common with intensive monitoring (52% vs 15%; P < .001), but there was no difference in the percentage of patients with any protocol deviation (91.6% vs 90.4%; P = .314). The reported incidence of trial outcomes between intensive and limited monitoring was similar for mortality (30 days: 4.8% vs 5.5%, P = .442; 1 year: 20.3% vs 21.3%, P = .473) and stroke (30 days: 2.8% vs 2.4%, P = .458), as well as most secondary trial outcomes with the exception of bleeding (intensive: 36.3% vs limited: 32.0% at 30 days, P = .019). There was a higher reported incidence of cardiac adverse events reported in the intensive monitoring group at 1 year (76.7% vs 72.4%; P = .019). CONCLUSIONS: Tailored limited monitoring strategies can be implemented without influencing the integrity of TAVR trial outcomes.

2.
Bioact Mater ; 9: 385-396, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34820578

RESUMO

Hydrogen has been used to suppress tumor growth with considerable efficacy. Inhalation of hydrogen gas and oral ingestion of hydrogen-rich saline are two common systemic routes of hydrogen administration. We have developed a topical delivery method of hydrogen at targeted sites through the degradation of magnesium-based biomaterials. However, the underlying mechanism of hydrogen's role in cancer treatment remains ambiguous. Here, we investigate the mechanism of tumor cell apoptosis triggered by the hydrogen released from magnesium-based biomaterials. We find that the localized release of hydrogen increases the expression level of P53 tumor suppressor proteins, as demonstrated by the in vitro RNA sequencing and protein expression analysis. Then, the P53 proteins disrupt the membrane potential of mitochondria, activate autophagy, suppress the reactive oxygen species in cancer cells, and finally result in tumor suppression. The anti-tumor efficacy of magnesium-based biomaterials is further validated in vivo by inserting magnesium wire into the subcutaneous tumor in a mouse. We also discovered that the minimal hydrogen concentration from magnesium wires to trigger substantial tumor apoptosis is 91.2 µL/mm3 per day, which is much lower than that required for hydrogen inhalation. Taken together, these findings reveal the release of H2 from magnesium-based biomaterial exerts its anti-tumoral activity by activating the P53-mediated lysosome-mitochondria apoptosis signaling pathway, which strengthens the therapeutic potential of this biomaterial as localized anti-tumor treatment.

3.
J Affect Disord ; 296: 315-321, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34600968

RESUMO

BACKGROUND: The majority of medical students in China have experienced home confinement and a reliance on online resources to study medicine since the outbreak of COVID-19. More time spent studying online during the COVID-19 pandemic may be a potential risk factor for problematic smartphone use, since smartphones have become the most commonly used device for accessing the internet. The objective of the present study was to explore the association between anxiety, smartphone problematic use and sleep disturbance among medical students during the enforced COVID-19 home confinement. METHODS: Altogether, 666 medical students validly answered a self-administered questionnaire, which included the Chinese version of the Generalized Anxiety Disorder scale, Smartphone addiction scale - short version, and the PROMIS Sleep Disturbance scale (short form). Hierarchical multiple regression analyses were employed to explore the associated factors of anxiety. Structural equation modeling was conducted to test hypothesized associations. RESULTS: Anxiety was significantly associated with problematic smartphone use and sleep disturbance among medical students during the COVID-19 pandemic. Problematic smartphone use not only directly affected anxiety, but also exerted a significant indirect effect on anxiety via sleep disturbance. A significant decrease of the path coefficient of problematic smartphone use on anxiety (from ß=0.53 to ß=0.22, P<0.01) was observed with sleep disturbance being modeled as a mediator. LIMITATIONS: Limitations include its cross-sectional design and samples recruited from only one medical school. CONCLUSIONS: The detrimental impact of problematic smartphone use and the importance of sleep health on mitigating anxiety should be highlighted and incorporated into medical education.


Assuntos
COVID-19 , Estudantes de Medicina , Ansiedade/epidemiologia , China/epidemiologia , Estudos Transversais , Humanos , Pandemias , SARS-CoV-2 , Sono , Smartphone
4.
Chemosphere ; 286(Pt 2): 131680, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34365166

RESUMO

In this study, a BDD electrolytic oxidation-ceramic membrane ultrafiltration (EO-CM) system for the removals of antibiotics, organic matters and ammonia in wastewater was evaluated. Sulfamethazine (SMZ) was degraded following a pseudo first-order kinetics. The removal rate of SMZ improved with the increase of electro-oxidation time (0-60 min) and current density (5-30 mA/cm2). During the BDD electro-oxidation process, H2O2 and hydroxyl radicals (•OH) were generated which were detected by N, N-diethyl-p-phenylenediamine (DPD) method and electron paramagnetic resonance spectroscopy (EPR), respectively. Chemical oxygen demand (COD) was able to be removed by EO and CM processes, in which proteins and humic acids were regarded as the main removed components measured using excitation-emission matrix (EEM) technique. Moreover, BDD electro-oxidation pretreatment could make the CM process maintain a high water flux and significantly control the membrane fouling and relieve transmembrane pollution. In addition, the removal of ammonia was enhanced with the increase of chloride ions (Cl-) in wastewater during EO process due to the generation of active chlorine (i.e., ClO-, HClO, or Cl2) from the oxidation of Cl-. Chloramine and nitrogen were produced in the oxidation of ammonia by active chlorine. Overall, the results of this study suggest that BDD EO-CM system is a promising process for removing antibiotics, organic matters and ammonia.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Amônia , Antibacterianos , Boro , Cerâmica , Diamante , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Ultrafiltração , Poluentes Químicos da Água/análise
5.
J Cancer Res Ther ; 17(5): 1186-1191, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34850766

RESUMO

Context: The incidences and risk factors caused by computed tomography (CT)-guided percutaneous computed tomography-guided needle biopsies (PCNBs) in elderly and young patients were not very clear. Aims: This study explored the different incidences of pneumothorax caused by PCNBs and related risk factors in elderly and young patients. Settings and Design: The medical records of 1100 patients who underwent CT-guided PCNBs in a hospital from January 2018 to December 2019 were retrospectively reviewed. Subjects and Methods: Data relating to the patients, lesions, techniques, and diagnoses were collected according to the ethical standards of the institutional research committee (registration number: KYLL-202008-145). Statistical Analysis Used: The variables were significant by univariate analysis and further analyzed by multivariate logistic regression analysis. Results: In the 1100 patients with PCNBs, the incidence of pneumothorax in groups ≥65 years old and <65 years old was 15.2% and 12.9%, respectively. There was no significant difference in the incidence of pneumothorax between the young and elderly patients. In elderly and young patients, emphysema along the needle path and dwell time was independent predictors. However, in young patients, lesion-abutting pleura was an independent risk factor for pneumothorax, but not in elderly patients. Conclusions: The risk of pneumothorax caused by CT-guided percutaneous core needle biopsy of the lung does not increase in elderly patients. Emphysema along the needle path and dwell time is independent predictors of pneumothorax in elderly and young patients.

6.
Brain Behav Immun ; 2021 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-34728390

RESUMO

BACKGROUND: Post-stroke depression (PSD) is the most common psychological consequence among stroke patients. Increased inflammatory markers resulted from ischemic stroke probably played an important role in pathogenesis of depressive symptomology. We aimed to determine the relationship among stroke severity, systemic low-grade inflammation and depressive symptomology. METHODS: A total of 897 patients were consecutively recruited in this prospective cohort study and followed up for 1 year. The sample consisted of 436 ischemic stroke patients (23.4% female, median age = 57 years) from this cohort. Serum concentrations of inflammatory markers were measured in all 436 ischemic stroke patients, from fasting morning venous blood draws on admission. Stroke severity was evaluated by National Institutes of Health Stroke Scale (NIHSS) on admission and post-stroke depressive symptomology were evaluated by 17-item Hamilton Rating Scale for Depression (HRSD) at 1 year after ischemic stroke. RESULTS: After fully adjusted for covariates, we observed that 1) NIHSS (Model 2: ß=0.200, 95%CI, 0.057∼0.332), fibrinogen (Model 2: ß=0.828, 95%CI, 0.269∼1.435), WBC (Model 2: ß=0.354, 95%CI, 0.122∼0.577) and neutrophil count (Model 2: ß=0.401, 95%CI, 0.126∼0.655) can independently predict the 1-year depressive symptomology after ischemic stroke; 2) fibrinogen (Indirect effect=0.027, 95%CI, 0.007∼0.063, 13.4% mediated), white blood count (WBC, Indirect effect=0.024, 95%CI, 0.005∼0.058, 11.8% mediated) and neutrophil counts (Indirect effect=0.030, 95%CI, 0.006∼0.069, 14.8% mediated) could partially mediated the association between stroke severity (NIHSS) and 1-year depressive symptomology, and 3) stroke severity might cause depressive symptomology partly through the chain mediating role of both fibrinogen and neutrophil count (chain mediated effect=0.003, 95%CI, 0.000∼0.011, p=0.025, 1.6% mediated). CONCLUSIONS: These results suggested that fibrinogen, WBC and neutrophil count in systemic low-grade inflammation might be significant predictors of 1-year post stroke depressive symptomology and partial mediators of the relationship between stroke severity and 1-year depressive symptomology among ischemic stroke patients. In addition, the chain mediating effect of fibrinogen and neutrophil count might play an important role in the occurrence of 1-year post stroke depressive symptomology. However, no inflammatory marker was associated with 1-year depressive symptomology in females.

7.
Front Oncol ; 11: 737520, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34737953

RESUMO

Pathological grading of meningioma is insufficient to predict recurrence after resection and to guide individualized treatment strategies. One hundred and thirty-three patients with meningiomas who underwent total resection were enrolled in this retrospective study. Univariate analyses were conducted to evaluate the association between factors and recurrence. Least absolute shrinkage and selection operator (Lasso) was used to further select variables to build a logistic model. The predictive efficiency of the model and WHO grade was compared by using receiver operating characteristic curve (ROC), decision curve analysis (DCA), and net reclassification improvement (NRI). Patients were given a new risk layer based on a nomogram. The recurrence of meningioma in different groups was observed through the Kaplan-Meier curve. Univariate analysis demonstrated that 11 risk factors were associated with prognosis (P < 0.05). The result of ROC proved that the quantified risk-scoring system (AUC = 0.853) had a higher benefit than pathological grade (AUC = 0.689, P = 0.011). The incidence of recurrence of the high risk cohort (69%) was significantly higher than that of the low risk cohort (9%) by Kaplan-Meier analysis (P < 0.001). And all patients who did not relapse in the high risk group received adjuvant radiotherapy. The novel risk stratification algorithm has a significant value for the recurrence of meningioma and can help in optimizing the individualized design of clinical therapy.

8.
Circulation ; 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34743530

RESUMO

Background: Differences in patient characteristics, changes in treatment algorithms, and advances in medical technology could each influence the applicability of older randomized trial results to contemporary clinical practice. The Dual Antiplatelet Therapy (DAPT) Study found that longer duration DAPT decreased ischemic events at the expense of greater bleeding, but subsequent evolution in stent technology and clinical practice may attenuate the benefit of prolonged DAPT in a contemporary population. We evaluated whether the DAPT Study population is different from a contemporary population of US patients receiving percutaneous coronary intervention (PCI), and estimated the treatment effect of extended duration antiplatelet therapy after PCI in this more contemporary cohort. Methods: We compared characteristics of drug-eluting stent (DES)-treated patients randomized in the DAPT Study to a sample of more contemporary DES-treated patients in the NCDR CathPCI Registry from July 2016-June 2017. After linking trial and registry data, we employed inverse-odds of trial participation weighting to account for patient and procedural characteristics and estimated a contemporary "real-world" treatment effect of 30 vs. 12 months of DAPT after coronary stent procedures. Results: The US DES-treated trial cohort included 8864 DAPT Study patients and the registry cohort included 568,540 patients. Compared to the trial population, registry patients had more comorbidities and were more likely to present with myocardial infarction and receive 2nd generation DES. After reweighting trial results to represent the registry population, there was no longer a significant effect of prolonged DAPT on reducing stent thrombosis (reweighted treatment effect: -0.40, 95% CI: -0.99%, 0.15%), major adverse cardiac and cerebrovascular events (reweighted treatment effect: -0.52, 95% CI: -2.62%, 1.03%), or myocardial infarction (reweighted treatment effect: -0.97%, 95% CI: -2.75%, 0.18%), but the increase in bleeding with prolonged DAPT persisted (reweighted treatment effect: 2.42%, 95% CI: 0.79%, 3.91%). Conclusions: Differences between patients and devices used in contemporary clinical practice compared with the DAPT Study were associated with attenuation of benefits and greater harms attributable to prolonged DAPT duration. These findings limit applicability of average treatment effects from the DAPT Study in modern clinical practice.

10.
Aesthet Surg J ; 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34758056

RESUMO

BACKGROUND: Although energy devices and botulinum toxin-A (BTX-A) could alleviate the age-related laxity, ptosis, and platysmal bands, they have limited efficacy on horizontal neck lines. OBJECTIVES: The purpose of this study was to investigate the efficacy, safety, and subject satisfaction of non-cross-linked hyaluronic acid (HA) compound filling plus mesotherapy combined treatment for the correction of horizontal neck lines, in comparison with BTX-A. METHODS: This multi-center, randomized, evaluator-blinded, prospective study enrolled female patients with moderate-to-severe horizontal neck lines corrected with either 2-3 sessions of non-cross-linked HA compound filling plus mesotherapy combined treatment or one session of BTX-A injection. Improvement of the neck lines grades, global aesthetic improvement scale (GAIS), patient satisfaction, and adverse events (AEs) were evaluated and compared on 1, 3, 6, and 10 months after the final treatment. RESULTS: Twenty-five patients received HA filling plus mesotherapy combined treatment and 23 received BTX-A injection. Compared with BTX-A, the HA compound filling plus mesotherapy combined treatment significantly improved the horizontal neck lines grades on all follow-up visits (P=0.000). Cases of different baseline grades (2, 2.5, and 3) demonstrated similar outcomes. The GAIS and patients' satisfaction ratings were significantly higher for the HA combined treatment group (P=0.000). Significantly higher pain ratings, higher incidence, and longer recovery of AEs (erythema, edema, and ecchymosis) were noticed in the combined treatment group (P<0.001). No serious AEs occurred. CONCLUSIONS: Compared with BTX-A, the HA compound filling plus mesotherapy combined treatment significantly improved moderate-to-severe horizontal neck lines and achieved a high level of patients' satisfaction.

11.
Nat Commun ; 12(1): 6755, 2021 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-34799591

RESUMO

Magnetoelastic effect characterizes the change of materials' magnetic properties under mechanical deformation, which is conventionally observed in some rigid metals or metal alloys. Here we show magnetoelastic effect can also exist in 1D soft fibers with stronger magnetomechanical coupling than that in traditional rigid counterparts. This effect is explained by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor. To facilitate practical applications, we further invented a textile magnetoelastic generator (MEG), weaving the 1D soft fibers with conductive yarns to couple the observed magnetoelastic effect with magnetic induction, which paves a new way for biomechanical-to-electrical energy conversion with short-circuit current density of 0.63 mA cm-2, internal impedance of 180 Ω, and intrinsic waterproofness. Textile MEG was demonstrated to convert the arterial pulse into electrical signals with a low detection limit of 0.05 kPa,  even with heavy perspiration or in underwater situations without encapsulations.

12.
Chemosphere ; : 132884, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34780738

RESUMO

In this work, the UV-induced transformation of monochloro-p-benzoquinone (MCBQ) in aqueous solution has been systematically investigated through quantum chemical calculations. During the UV irradiation at 253.7 nm, the first triplet state of MCBQ (3MCBQ*) was from the intersystem crossing of its first excited singlet state (1MCBQ*). In aqueous solution, the nucleophilic attack of OH- on carbon atoms in 3MCBQ* was the central reaction. The addition of OH- to olefinic carbon atoms was much more kinetically feasible than that to carbonyl carbon atoms, even though the carbonyl carbon atoms were more positively charged. Moreover, OH- preferred to add to the ortho-position of C-Cl bond, where the unchlorinated atom was more negatively charged than the chlorinated one. The UV photolysis of the primary intermediate (HO-CBQ) was not the same as that of MCBQ. The attack of OH- on the para-position of C-Cl bond was the most efficient pathway. The addition of OH- to the chlorinated atom of 3HO-CBQ* was much more efficient than that in the case of 3MCBQ*, which reveals that more UV irradiation may promote the dechlorination. The findings in the present study may be helpful to enrich the understanding of the halobenzoquinones transformation in aqueous solution.

13.
Artigo em Inglês | MEDLINE | ID: mdl-34797630

RESUMO

Much has been learned about the protein coronae and their biological implications within the context of nanomedicine and nanotoxicology. However, no data is available about the protein coronae associated with nanoparticles undergoing spontaneous surface-energy minimization, a common phenomenon during the synthesis and shelf life of nanomaterials. Accordingly, here we employed gold nanoparticles (AuNPs) possessing the three initial states of spiky, midspiky, and spherical shapes and determined their acquisition of human plasma protein coronae with label-free mass spectrometry. The AuNPs collected coronal proteins that were different in abundance, physicochemical parameters, and interactive biological network. The size and structure of the coronal proteins matched the morphology of the AuNPs, where small globular proteins and large fibrillar proteins were enriched on spiky AuNPs, while large proteins were abundant on spherical AuNPs. Furthermore, the AuNPs induced endothelial leakiness to different degrees, which was partially negated by their protein coronae as revealed by confocal fluorescence microscopy, in vitro and ex vivo transwell assays, and signaling pathway assays. This study has filled a knowledge void concerning the dynamic protein corona of nanoparticles possessing an evolving morphology and shed light on their implication for future nanomedicine harnessing the paracellular pathway.

14.
Dalton Trans ; 50(45): 16703-16710, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34761779

RESUMO

Sodium silicide Na4Si4 is a reductive and reactive source of silicon highly relevant to designing non-oxidic silicon materials, including clathrates, various silicon allotropes, and metal silicides. Despite the importance of this compound, its production in high amounts and high purity is still a bottleneck with reported methods. In this work, we demonstrate that readily available silicon nanoparticles react with sodium hydride with a stoichiometry close to the theoretical one and at a temperature of 395 °C for shorter duration than previously reported. This enhanced reactivity of silicon nanoparticles makes the procedure robust and less dependent on experimental parameters, such as gas flow. As a result, we deliver a procedure to achieve Na4Si4 with purity of ca. 98 mol% at the gram scale. We show that this compound is an efficient precursor to deliver selectively type I and type II sodium silicon clathrates depending on the conditions of thermal decomposition.

15.
Biosens Bioelectron ; 197: 113784, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34801798

RESUMO

BCR/ABL fusion gene has been discovered as an important and reliable biomarker for early diagnosis of chronic myeloid leukemia (CML). Herein, a novel and switching electrochemiluminescence (ECL) biosensor was developed for ultrasensitive determination of the fusion gene based on the self-enhanced polyethyleneimine-luminol (PEI-Lum) hydrogels coupled with target-initiated DNAzyme motor. The facilely prepared PEI-Lum hydrogels could not only immobilize enormous luminol but shorten the distance of binary system, thus facilitating the mass and electron transfer efficiency of the sensing interface, so that the enhanced ECL signal was achieved. Moreover, the engineering DNA motor was powered by Mg2+-dependent DNAzyme for isothermal DNA signal amplification. As a result, the fabricated ECL biosensor enabled highly sensitive detection of BCR/ABL fusion gene with a broad linear range from 10.0 fM to 10.0 nM and a low detection limit of 3.75 fM (S/N = 3). Significantly, the developed biosensing method provides a potential tool for nucleic acid analysis in clinical diagnosis and a new avenue to design high-efficient ECL nanomaterials.

16.
PLoS Biol ; 19(11): e3001445, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34758021

RESUMO

Cochlear supporting cells (SCs) are glia-like cells critical for hearing function. In the neonatal cochlea, the greater epithelial ridge (GER) is a mitotically quiescent and transient organ, which has been shown to nonmitotically regenerate SCs. Here, we ablated Lgr5+ SCs using Lgr5-DTR mice and found mitotic regeneration of SCs by GER cells in vivo. With lineage tracing, we show that the GER houses progenitor cells that robustly divide and migrate into the organ of Corti to replenish ablated SCs. Regenerated SCs display coordinated calcium transients, markers of the SC subtype inner phalangeal cells, and survive in the mature cochlea. Via RiboTag, RNA-sequencing, and gene clustering algorithms, we reveal 11 distinct gene clusters comprising markers of the quiescent and damaged GER, and damage-responsive genes driving cell migration and mitotic regeneration. Together, our study characterizes GER cells as mitotic progenitors with regenerative potential and unveils their quiescent and damaged translatomes.

17.
Front Immunol ; 12: 769425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34804059

RESUMO

Pancreatic cancer (PAAD) is one of the most malignant cancers and immune microenvironment has been proved to be involved in pathogenesis of PAAD. m6A modification, related to the expression of m6A regulators, participates in the development of multiple cancers. However, the correlation between m6A regulators and immune microenvironment was largely unknown in PAAD. And because of the small sample size of pancreatic cancer in the TCGA database, it is not enough to draw a convincing conclusion. In the present study, we downloaded seven pancreatic cancer datasets with survival data and removed batch effects among these datasets to be used as the PAAD cohort to analyze the immune landscape of PAAD and the expression pattern of m6A regulators and divided the integrated dataset into cluster 1 and cluster 2 by consensus clustering for m6A regulators. Lower m6A regulators were found to be related to higher immune cell infiltration and a better survival. Moreover, we identified six m6A regulators and constructed the prognostic signature of m6A regulators. Patients with low-risk score had a higher response to immune checkpoint inhibitor and a longer overall survival. To figure out the underlying mechanism, we analyzed the cancer immunity cycle, most altered genes, gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) in risk subtypes. In summary, the present study proved m6A regulators modulated the PAAD immune microenvironment. And risk scores served as predictive indicator for immunotherapy and played a prognostic role for PAAD patients. Our study provided novel therapeutic targets to improve immunotherapy efficacy.

18.
Artigo em Inglês | MEDLINE | ID: mdl-34808061

RESUMO

This study experimentally substantiates that the micromechanical compatibility between cell and substrate is essential for cells to achieve energetically favorable mechanotransduction that directs phenotypic transitions. The argument for this compatibility is based on a thermodynamic model that suggests that the response of cells to their substrate mechanical environment is a consequence of the interchange between forms of energy governing the cell-substrate interaction. Experimental validation for the model has been carried out by investigating the osteogenic differentiation of dental follicle stem cells (DFSCs) seeded on electrospun fibrous scaffolds. Electrospinning of blends containing polycaprolactone (PCL) and silk fibroin (SF) with varying composition of cellulose nanocrystals (CNCs) resulted in three-dimensional (3D) fibrous scaffolds with bimodal distribution of fiber diameter, which provides both macroscopically stiff and microscopically compliant scaffolds for cells without affecting the surface chemical functionality of scaffolds. Atomic force microscopy (AFM) with a colloidal probe and single-cell force spectroscopy were used to characterize cell stiffness and scaffold stiffness on the cellular level, as well as cell-scaffold adhesive interaction (chemical functionality). This study has successfully varied scaffold mechanical properties without affecting their surface chemistry. In vitro tests indicate that the micromechanical compatibility between cells and scaffolds has been significantly correlated with mechanosensitive gene expression markers and osteogenic differentiation markers of DFSCs. The agreement between experimental observations and the thermodynamic model affirms that the cellular response to the mechanical environment, though biological in nature, follows the laws of the energy interchange to achieve its self-regulating behavior. More importantly, this study provides systematic evidence, through extensive and rigorous experimental studies, for the first time that rationalizes that micromechanical compatibility is indeed important to the efficacy of regenerative medicine.

19.
Polymers (Basel) ; 13(22)2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34833256

RESUMO

Peripheral nerve injury (PNI) is an unresolved medical problem with limited therapeutic effects. Epineurium neurorrhaphy is an important method for treating PNI in clinical application, but it is accompanied by inevitable complications such as the misconnection of nerve fibers and neuroma formation. Conduits small gap tubulization has been proved to be an effective suture method to replace the epineurium neurorrhaphy. In this study, we demonstrated a method for constructing peripheral nerve conduits based on the principle of chitosan acetylation. In addition, the micromorphology, mechanical properties and biocompatibility of the chitin nerve conduits formed by chitosan acetylation were further tested. The results showed chitin was a high-quality biological material for constructing nerve conduits. Previous reports have demonstrated that mesenchymal stem cells culture as spheroids can improve the therapeutic potential. In the present study, we used a hanging drop protocol to prepare bone marrow mesenchymal stem cell (BMSCs) spheroids. Meanwhile, spherical stem cells could express higher stemness-related genes. In the PNI rat model with small gap tubulization, BMSCs spheres exhibited a higher ability to improve sciatic nerve regeneration than BMSCs suspension. Chitin nerve conduits with BMSCs spheroids provide a promising therapy option for peripheral nerve regeneration.

20.
Genomics ; 113(6): 4116-4125, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34743958

RESUMO

Our objective was to evaluate the effect of colostrum feeding times on genome-wide gene expression of neonatal calves. In total, twenty-seven calves were assigned to three colostrum feeding treatments: within 45 min (TRT0h, n = 9), 6 h (TRT6h, n = 9) and 12 h (TRT12h, n = 9). Ileum tissues were collected at 51 h and transcriptomic analysis was conducted. Uniquely expressed genes were identified in TRT0h group with enriched "Antigen Presentation" function. Meanwhile, the weighted gene co-expression network analysis (WGCNA) identified four significant gene modules (|correlation| > 0.50 and P ≤ 0.05). In particular, Turquoise gene module with the enriched "Cadherin binding involved in cell-cell adhesion" and "Cell-cell adherences junction" GO terms were significantly correlated with Faecalibacterium prausnitzii (R = -0.70, P < 0.01) and Bifidobacterium (R = -0.55, P < 0.01). Our findings suggest feeding colostrum without delay could stimulate the expression of genes involved in immune function development related to host response and microbial colonization in neonatal claves.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...