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1.
Neurochem Res ; 49(3): 557-567, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38063946

RESUMEN

Stroke, the second-largest cause of death and the leading cause of disability globally, presents significant challenges in terms of prognosis and treatment. Identifying reliable prognosis biomarkers and treatment targets is crucial to address these challenges. Circular RNA (circRNA) has emerged as a promising research biomarkers and therapeutic targets because of its tissue specificity and conservation. However, the potential role of circRNA in stroke prognosis and treatment remains largely unexplored. This review briefly elucidate the mechanism underlying circRNA's involvement in stroke pathophysiology. Additionally, this review summarizes the impact of circRNA on different forms of strokes, including ischemic stroke and hemorrhagic stroke. And, this article discusses the positive effects of circRNA on promoting cerebrovascular repair and regeneration, maintaining the integrity of the blood-brain barrier (BBB), and reducing neuronal injury and immune inflammatory response. In conclusion, the significance of circRNA as a potential prognostic biomarker and a viable therapeutic target was underscored.


Asunto(s)
Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , ARN Circular/genética , Accidente Cerebrovascular/genética , Accidente Cerebrovascular/terapia , Biomarcadores , Barrera Hematoencefálica
2.
Plant Cell Rep ; 43(6): 143, 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38750149

RESUMEN

Key message BdDREB-39 is a DREB/CBF transcription factor, localized in the nucleus with transactivation activity, and BdDREB-39-overexpressing transgenic yeasts and tobacco enhanced the tolerance to oxidative stress.Abstract The DREB/CBF transcription factors are generally recognized to play an important factor in plant growth, development and response to various abiotic stresses. However, the mechanism of DREB/CBFs in oxidative stress response is largely unknown. This study isolated a DREB/CBF gene BdDREB-39 from Brachypodium distachyon (B. distachyon). Multiple sequence alignment and phylogenetic analysis showed that BdDREB-39 was closely related to the DREB proteins of oats, barley, wheat and rye and therefore its study can provide a reference for the excavation and genetic improvement of BdDREB-39 or its homologs in its closely related species. The transcript levels of BdDREB-39 were significantly up-regulated under H2O2 stress. BdDREB-39 was localised in the nucleus and functioned as a transcriptional activator. Overexpression of BdDREB-39 enhanced H2O2 tolerance in yeast. Transgenic tobaccos with BdDREB-39 had higher germination rates, longer root, better growth status, lesser reactive oxygen species (ROS) and malondialdehyde (MDA), and higher superoxide dismutase (SOD) and peroxidase (POD) activities than wild type (WT). The expression levels of ROS-related and stress-related genes were improved by BdDREB-39. In summary, these results revealed that BdDREB-39 can improve the viability of tobacco by regulating the expression of ROS and stress-related genes, allowing transgenic tobacco to accumulate lower levels of ROS and reducing the damage caused by ROS to cells. The BdDREB-39 gene has the potential for developing plant varieties tolerant to stress.


Asunto(s)
Brachypodium , Regulación de la Expresión Génica de las Plantas , Peróxido de Hidrógeno , Nicotiana , Estrés Oxidativo , Proteínas de Plantas , Plantas Modificadas Genéticamente , Factores de Transcripción , Nicotiana/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Oxidativo/genética , Brachypodium/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Peróxido de Hidrógeno/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Filogenia
3.
Med Sci Monit ; 30: e943940, 2024 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-38288559

RESUMEN

This publication has been retracted by the Editor due to the identification of non-original figure images and manuscript content that raise concerns regarding the credibility and originality of the study. Reference: Jin-Cheng Zheng, Ke-Jie Chang, Yu-Xiang Jin, Xue-Wei Zhao, Bing Li, Meng-Hang Yang. Arsenic Trioxide Inhibits the Metastasis of Small Cell Lung Cancer by Blocking Calcineurin-Nuclear Factor of Activated T Cells (NFAT) Signaling. Med Sci Monit 2019; 25:2228-2237. DOI: 10.12659/MSM.913091.

4.
BMC Public Health ; 24(1): 740, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38454384

RESUMEN

BACKGROUND: Despite the growing interest in hospital rehabilitation services for communities, studies on existing community-based rehabilitation (CBR) services remain scarce owing to limitations in the development of community health services and regional cultural diversity. As a guaranteed measure for ensuring the quality of rehabilitation services and achieving the desired service outcomes, clear roles and responsibilities in multidisciplinary teams and effective service delivery are particularly important. OBJECTIVE: This scoping review aimed to determine the scope of community stroke rehabilitation programs involving existing multidisciplinary teams and to analyze the implementation content and implementers' functional roles to provide guidance for future CBR programs. METHODS: The scoping review design followed the methodology of the Joanna Briggs Institute and was based on the normative scoping review framework proposed by Arksey and O'Malley. The comprehensive CBR framework was proposed by World Health Organization-guided data charting and analysis. RESULTS: Of the 22,849 identified citations, 74 studies were included, consisting of 6,809 patients with stroke and 49 primary caregivers, most of whom were from China. The most common working mode in CBR programs was a dual approach involving both healthcare professionals in medical institutions and community healthcare professionals. The number of programs in each discipline was in the following descending order: nursing, medical care, rehabilitation, psychology, nutrition, and public health. Among these, multidisciplinary teams comprising medical, nursing, and rehabilitation disciplines were the most common, with a total of 29 programs. Disciplinary members were mainly responsible for implementing their respective disciplinary content, with physicians providing guidance for the programs. More than 82.4% of the studies reported 2-4 intervention strategies. The intervention forms of rehabilitation content were the most diverse, whereas preventive interventions were more homogeneous than others. Physical function and socio-psychological measurements were the most commonly reported outcomes. CONCLUSION: CBR services implemented by multidisciplinary teams can effectively achieve functional and emotional improvement in patients with stroke, and nurses are the most involved in implementation, especially in community settings. The results further emphasize the importance of strengthening the exploration of nurses' maximum potential to implement CBR plans in future practice. TRIAL REGISTRATION: The registration information for this scoping review can be found at osf.io/pv7tg.


Asunto(s)
Servicios de Salud Comunitaria , Accidente Cerebrovascular , Adulto , Humanos , Grupos de Población , Hospitales , Grupo de Atención al Paciente , Accidente Cerebrovascular/terapia
5.
J Basic Microbiol ; 64(4): e2300705, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38253966

RESUMEN

Ergothioneine (EGT) is a rare thiohistidine derivative with exceptional antioxidant properties. The blood level of EGT is considered highly reliable predictors for cardiovascular diseases and mortality, yet animals lack the ability to synthesize this compound. Free plasmids have been previously used to overexpress genes involved in the EGT biosynthetic pathway of Mycolicibacterium neoaurum. Here, we tentatively introduced a putative transporter gene mfsT1 into high-copy plasmids and sharply increased the ratio of extracellular EGT concentration from 18.7% to 44.9%. Subsequently, an additional copy of egtABCDE, hisG, and mfsT1 was inserted into the genome with a site-specific genomic integration tool of M. neoaurum, leading a 2.7 times increase in EGT production. Co-enhancing the S-adenosyl-L-methionine regeneration pathway, or alternatively, the integration of three copies of egtABCDE, hisG and mfsT1 into the genome further increased the total EGT yield by 16.1% (64.6 mg/L) and 21.7% (67.7 mg/L), respectively. After 168-h cultivation, the highest titer reached 85.9 mg/L in the latter strain with three inserted copies. This study provided a solid foundation for genome engineering to increase the production of EGT in M. neoaurum.


Asunto(s)
Ergotioneína , Mycobacteriaceae , Animales , Ergotioneína/genética , Ergotioneína/metabolismo , Antioxidantes/metabolismo
6.
Neurobiol Dis ; 180: 106078, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36914076

RESUMEN

Traumatic brain injury (TBI) is commonly followed by intractable psychiatric disorders and long-term changes in affect, such as anxiety. The present study sought to investigate the effect of repetitive intranasal delivery of interleukin-4 (IL-4) nanoparticles on affective symptoms after TBI in mice. Adult male C57BL/6 J mice (10-12 weeks of age) were subjected to controlled cortical impact (CCI) and assessed by a battery of neurobehavioral tests up to 35 days after CCI. Neuron numbers were counted in multiple limbic structures, and the integrity of limbic white matter tracts was evaluated using ex vivo diffusion tensor imaging (DTI). As STAT6 is a critical mediator of IL-4-specific transcriptional activation, STAT6 knockout mice were used to explore the role of endogenous IL-4/STAT6 signaling axis in TBI-induced affective disorders. We also employed microglia/macrophage (Mi/Mϕ)-specific PPARγ conditional knockout (mKO) mice to test if Mi/Mϕ PPARγ critically contributes to IL-4-afforded beneficial effects. We observed anxiety-like behaviors up to 35 days after CCI, and these measures were exacerbated in STAT6 KO mice but mitigated by repetitive IL-4 delivery. We discovered that IL-4 protected against neuronal loss in limbic structures, such as the hippocampus and the amygdala, and improved the structural integrity of fiber tracts connecting the hippocampus and amygdala. We also observed that IL-4 boosted a beneficial Mi/Mϕ phenotype (CD206+/Arginase 1+/PPARγ+ triple-positive) in the subacute injury phase, and that the numbers of Mi/Mϕ appositions with neurons were robustly correlated with long-term behavioral performances. Remarkably, PPARγ-mKO completely abolished IL-4-afforded protection. Thus, CCI induces long-term anxiety-like behaviors in mice, but these changes in affect can be attenuated by transnasal IL-4 delivery. IL-4 prevents the long-term loss of neuronal somata and fiber tracts in key limbic structures, perhaps due to a shift in Mi/Mϕ phenotype. Exogenous IL-4 therefore holds promise for future clinical management of mood disturbances following TBI.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Microglía , Ratones , Masculino , Animales , PPAR gamma , Interleucina-4 , Imagen de Difusión Tensora , Ratones Endogámicos C57BL , Ratones Noqueados , Ansiedad/etiología , Neuronas
7.
J Neuroinflammation ; 19(1): 281, 2022 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-36403074

RESUMEN

BACKGROUND: The long-term functional recovery of traumatic brain injury (TBI) is hampered by pathological events, such as parenchymal neuroinflammation, neuronal death, and white matter injury. Krüppel-like transcription factor 11 (KLF 11) belongs to the zinc finger family of transcription factors and actively participates in various pathophysiological processes in neurological disorders. Up to now, the role and molecular mechanisms of KLF11 in regulating the pathogenesis of brain trauma is poorly understood. METHODS: KLF11 knockout (KO) and wild-type (WT) mice were subjected to experimental TBI, and sensorimotor and cognitive functions were evaluated by rotarod, adhesive tape removal, foot fault, water maze, and passive avoidance tests. Brain tissue loss/neuronal death was examined by MAP2 and NeuN immunostaining, and Cresyl violet staining. White matter injury was assessed by Luxol fast blue staining, and also MBP/SMI32 and Caspr/Nav1.6 immunostaining. Activation of cerebral glial cells and infiltration of blood-borne immune cells were detected by GFAP, Iba-1/CD16/32, Iba-1/CD206, Ly-6B, and F4/80 immunostaining. Brian parenchymal inflammatory cytokines were measured with inflammatory array kits. RESULTS: Genetic deletion of KLF11 worsened brain trauma-induced sensorimotor and cognitive deficits, brain tissue loss and neuronal death, and white matter injury in mice. KLF11 genetic deficiency in mice also accelerated post-trauma astrocytic activation, promoted microglial polarization to a pro-inflammatory phenotype, and increased the infiltration of peripheral neutrophils and macrophages into the brain parenchyma. Mechanistically, loss-of-KLF11 function was found to directly increase the expression of pro-inflammatory cytokines in the brains of TBI mice. CONCLUSION: KLF11 acts as a novel protective factor in TBI. KLF11 genetic deficiency in mice aggravated the neuroinflammatory responses, grey and white matter injury, and impaired long-term sensorimotor and cognitive recovery. Elucidating the functional importance of KLF11 in TBI may lead us to discover novel pharmacological targets for the development of effective therapies against brain trauma.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Lesiones Encefálicas , Animales , Ratones , Ratones Endogámicos C57BL , Lesiones Traumáticas del Encéfalo/patología , Lesiones Encefálicas/metabolismo , Citocinas/genética , Factores de Transcripción de Tipo Kruppel/genética
8.
Circ Res ; 126(8): 1040-1057, 2020 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-32131693

RESUMEN

RATIONALE: Angiogenesis promotes neurological recovery after stroke and is associated with longer survival of stroke patients. Cerebral angiogenesis is tightly controlled by certain microRNAs (miRs), such as the miR-15a/16-1 cluster, among others. However, the function of the miR-15a/16-1 cluster in endothelium on postischemic cerebral angiogenesis is not known. OBJECTIVE: To investigate the functional significance and molecular mechanism of endothelial miR-15a/16-1 cluster on angiogenesis in the ischemic brain. METHODS AND RESULTS: Endothelial cell-selective miR-15a/16-1 conditional knockout (EC-miR-15a/16-1 cKO) mice and wild-type littermate controls were subjected to 1 hour middle cerebral artery occlusion followed by 28-day reperfusion. Deletion of miR-15a/16-1 cluster in endothelium attenuates post-stroke brain infarction and atrophy and improves the long-term sensorimotor and cognitive recovery against ischemic stroke. Endothelium-targeted deletion of the miR-15a/16-1 cluster also enhances post-stroke angiogenesis by promoting vascular remodeling and stimulating the generation of newly formed functional vessels, and increases the ipsilateral cerebral blood flow. Endothelial cell-selective deletion of the miR-15a/16-1 cluster up-regulated the protein expression of pro-angiogenic factors VEGFA (vascular endothelial growth factor), FGF2 (fibroblast growth factor 2), and their receptors VEGFR2 (vascular endothelial growth factor receptor 2) and FGFR1 (fibroblast growth factor receptor 1) after ischemic stroke. Consistently, lentiviral knockdown of the miR-15a/16-1 cluster in primary mouse or human brain microvascular endothelial cell cultures enhanced in vitro angiogenesis and up-regulated pro-angiogenic proteins expression after oxygen-glucose deprivation, whereas lentiviral overexpression of the miR-15a/16-1 cluster suppressed in vitro angiogenesis and down-regulated pro-angiogenic proteins expression. Mechanistically, miR-15a/16-1 translationally represses pro-angiogenic factors VEGFA, FGF2, and their receptors VEGFR2 and FGFR1, respectively, by directly binding to the complementary sequences within 3'-untranslated regions of those messenger RNAs. CONCLUSIONS: Endothelial miR-15a/16-1 cluster is a negative regulator for postischemic cerebral angiogenesis and long-term neurological recovery. Inhibition of miR-15a/16-1 function in cerebrovascular endothelium may be a legitimate therapeutic approach for stroke recovery.


Asunto(s)
Endotelio Vascular/metabolismo , MicroARNs/metabolismo , Neovascularización Fisiológica/fisiología , Recuperación de la Función/fisiología , Accidente Cerebrovascular/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Endotelio Vascular/patología , Eliminación de Gen , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , MicroARNs/genética , Accidente Cerebrovascular/genética , Accidente Cerebrovascular/patología , Factores de Tiempo
9.
Mol Biol Rep ; 49(3): 2245-2253, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35028858

RESUMEN

BACKGROUND: Small cell lung cancer (SCLC) is the most malignant type of lung cancer. We previously reported that arsenic trioxide (As2O3) inhibited tumor initiating cells (TICs) of SCLC in vitro. In the present study, we aimed to identify the above effect in vivo and shed light on its underlying mechanism. METHODS AND RESULTS: TICs were enriched by culturing human SCLC cell line as sphere cells in specified serum-free medium. The expression of stem cell markers, CD133 and CD44, and the in vivo tumorigenicity of both TICs and their parental cells were examined. To demonstrate the inhibitory effect of As2O3 on TICs, cell proliferation, clone formation and sphere formation assays were performed. CD133 and Notch pathway-related factors were also measured after As2O3 treatment. Xenograft models were established by injecting TICs into nude mice. Mice were treated with As2O3 for 14 days. Afterwards, the tumor volume and the expression of CD133 and Notch1 were evaluated. TICs obtained by the above-mentioned method showed elevated levels of stem cell markers and increased tumorigenicity compared with their parental cells. As2O3 treatment largely inhibited TICs proliferation, sphere formation and clonogenic capacity. As2O3 also reduced the expression of CD133 and down-regulated Notch pathway in TICs. Furthermore, As2O3 potently inhibited tumor growth, decreased the expression of CD133 and down-regulated Notch1 in tumors originating from TICs. CONCLUSIONS: Our data demonstrate that As2O3 has a remarkable inhibitory effect on TICs of SCLC both in vitro and in vivo, and the mechanism might involve the down-regulation of Notch pathway.


Asunto(s)
Antineoplásicos , Arsenicales , Neoplasias Pulmonares , Carcinoma Pulmonar de Células Pequeñas , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Apoptosis , Trióxido de Arsénico/farmacología , Trióxido de Arsénico/uso terapéutico , Arsenicales/farmacología , Arsenicales/uso terapéutico , Línea Celular Tumoral , Humanos , Neoplasias Pulmonares/metabolismo , Ratones , Ratones Desnudos , Células Madre Neoplásicas/metabolismo , Carcinoma Pulmonar de Células Pequeñas/tratamiento farmacológico
10.
J Clin Lab Anal ; 36(4): e24332, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35257419

RESUMEN

BACKGROUND: Although the phosphorylation of 4E-BP1 that has been detected in high-grade prostate cancer has been reported in previous studies, overexpression of p4E-BP1 and 4EBP1 and their clinical significance in prostate cancer still remain unknown. METHODS: One hundred six samples of prostate tissues were collected and analyzed by immunohistochemistry with p4E-BP1 or 4E-BP1 specific antibodies. Everolimus was used to block the phosphorylation of p4E-BP1, and then flow cytometry, clone formation, transwell, and wound healing assays were performed to detect the survival and invasive ability of the prostate cancer cells. RESULTS: We found that the expression of 4E-BP1 and p4E-BP1 was higher in prostate cancer tissues than in normal tissues. Interestingly, the expression of p4E-BP1 was significantly associated with Gleason score and lymph node metastasis, but had no obvious correlation with PSA and the presence of bone or visceral metastasis. However, no evident correlation was found between the positive expression of 4E-BP1 and these clinical characteristics. In in vitro experiments, we found similar results as the clinical presentation that 4E-BP1 and p4E-BP1 were low expressed in normal prostate epithelial cells, but in prostate cancer cells, as the malignancy increasing, 4E-BP1 and p4E-BP1 expression also gradually increased. Then, we used Everolimus to inhibit the phosphorylation of 4E-BP1 and found that Everolimus effectively reduced cloning formation, inhibited cell migration, and promoted apoptosis in a dose-dependent manner in PC3 cells. CONCLUSIONS: These findings suggest that p4E-BP1 is a potential biomarker and therapy target for prostate cancer, and patients with high expressions of p4E-BP1 may benefit from Everolimus treatment.


Asunto(s)
Everolimus , Neoplasias de la Próstata , Everolimus/farmacología , Humanos , Inmunohistoquímica , Masculino , Fosfoproteínas , Fosforilación
11.
Int J Mol Sci ; 23(18)2022 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-36142194

RESUMEN

The immediate early protein 1 (IE1) acts as a transcriptional activator and is essential for viral gene transcription and viral DNA replication. However, the key regulatory domains of IE1 remain poorly understood. Here, we analyzed the sequence characteristics of Bombyx mori nucleopolyhedrovirus (BmNPV) IE1 and identified the key functional domains of BmNPV IE1 by stepwise truncation. Our results showed that BmNPV IE1 was highly similar to Autographa californica nucleopolyhedrovirus (AcMNPV) IE1, but was less conserved with IE1 of other baculoviruses, the C-terminus of IE1 was more conserved than the N-terminus, and BmNPV IE1 was also necessary for BmNPV proliferation. Moreover, we found that IE1158-208 was a major nuclear localization element, and IE11-157 and IE1539-559 were minor nuclear localization elements, but the combination of these two minor elements was equally sufficient to fully mediate the nuclear entry of IE1. Meanwhile, IE11-258, IE1560-584, and the association of amino acids 258 and 259 were indispensable for the transactivation activity of BmNPV IE1. These results systematically resolve the functional domains of BmNPV IE1, which contribute to the understanding of the mechanism of baculovirus infection and provide a possibility to synthesize a small molecule IE1-truncated mutant as an agonist or antagonist.


Asunto(s)
Bombyx , Replicación del ADN , Aminoácidos/metabolismo , Animales , Bombyx/metabolismo , ADN Viral , Regulación Viral de la Expresión Génica , Proteínas de Insectos/genética , Nucleopoliedrovirus , Transactivadores/metabolismo , Replicación Viral
12.
Molecules ; 27(17)2022 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-36080154

RESUMEN

Radix Asteris (RA), also known as 'Zi Wan', is the dried root and rhizome of Aster tataricus L. f., which has been used to treat cough and asthma in many countries such as China, Japan, Korea and Vietnam. This article summarizes the available information on RA in ancient Chinese medicine books and modern research literature: its botanical properties, traditional uses, chemical composition, pharmacological activity, toxicity and quality control. Studies have shown that RA extracts contain terpenes, triterpenoid saponins, organic acids, peptides and flavonoids, and have various pharmacological activities such as anti-inflammatory, anti-tumor, anti-oxidation, and anti-depression. RA is considered to be a promising medicinal plant based on its traditional use, chemical constituents and pharmacological activities. However, there are few studies on its toxicity and the consistency of its components, which indicates the need for further in-depth studies on the toxicity and quality control of RA and its extracts.


Asunto(s)
Aster , Medicamentos Herbarios Chinos , Plantas Medicinales , Antiinflamatorios , Medicamentos Herbarios Chinos/química , Etnofarmacología , Medicina Tradicional China , Fitoquímicos/farmacología , Fitoquímicos/uso terapéutico , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico
13.
Angew Chem Int Ed Engl ; 61(21): e202117820, 2022 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-35263001

RESUMEN

Intermolecular C-H silylation for the synthesis of acyclic silanes bearing a silicon-stereogenic center in one enantiomeric form remains unknown to date. Herein, we report the first enantioselective intermolecular C-H silylation of heteroarenes for the synthesis of acyclic silicon-stereogenic heteroarylsilanes. This process undergoes a rhodium-catalyzed direct intermolecular dehydrogenative Si-H/C-H cross-coupling, giving access to a variety of acyclic heteroarylated silicon-stereogenic monohydrosilanes, including bis-Si-stereogenic silanes, in decent yields with excellent chemo-, regio-, and stereo-control, which significantly enlarge the chemical space of the optically active silicon-stereogenic monohydrosilanes.

14.
Electrophoresis ; 42(21-22): 2264-2272, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34278592

RESUMEN

Biological cells in vivo typically reside in a dynamic flowing microenvironment with extensive biomechanical and biochemical cues varying in time and space. These dynamic biomechanical and biochemical signals together act to regulate cellular behaviors and functions. Microfluidic technology is an important experimental platform for mimicking extracellular flowing microenvironment in vitro. However, most existing microfluidic chips for generating dynamic shear stress and biochemical signals require expensive, large peripheral pumps and external control systems, unsuitable for being placed inside cell incubators to conduct cell biology experiments. This study has developed a microfluidic generator of dynamic shear stress and biochemical signals based on autonomously oscillatory flow. Further, based on the lumped-parameter and distributed-parameter models of multiscale fluid dynamics, the oscillatory flow field and the concentration field of biochemical factors has been simulated at the cell culture region within the designed microfluidic chip. Using the constructed experimental system, the feasibility of the designed microfluidic chip has been validated by simulating biochemical factors with red dye. The simulation results demonstrate that dynamic shear stress and biochemical signals with adjustable period and amplitude can be generated at the cell culture chamber within the microfluidic chip. The amplitudes of dynamic shear stress and biochemical signals is proportional to the pressure difference and inversely proportional to the flow resistance, while their periods are correlated positively with the flow capacity and the flow resistance. The experimental results reveal the feasibility of the designed microfluidic chip. Conclusively, the proposed microfluidic generator based on autonomously oscillatory flow can generate dynamic shear stress and biochemical signals without peripheral pumps and external control systems. In addition to reducing the experimental cost, due to the tiny volume, it is beneficial to be integrated into cell incubators for cell biology experiments. Thus, the proposed microfluidic chip provides a novel experimental platform for cell biology investigations.


Asunto(s)
Microfluídica , Técnicas de Cultivo de Célula , Dispositivos Laboratorio en un Chip , Estrés Mecánico
15.
Analyst ; 146(19): 5913-5922, 2021 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-34570848

RESUMEN

To reproduce hemodynamic stress microenvironments of endothelial cells in vitro is of vital significance, by which one could exploit the quantitative impact of hemodynamic stresses on endothelial function and seek innovative approaches to prevent circulatory system diseases. Although microfluidic technology has been regarded as an effective method to create physiological microenvironments, a microfluidic system to precisely reproduce physiological arterial hemodynamic stress microenvironments has not been reported yet. In this paper, a novel microfluidic chip consisting of a cell culture chamber with on-chip afterload components designed by the principle of input impedance to mimic the global hemodynamic behaviors is proposed. An external feedback control system is developed to accurately generate the input pressure waveform. A lumped parameter hemodynamic model (LPHM) is built to represent the input impedance to mimic the on-chip global hemodynamic behaviors. Sensitivity analysis of the model parameters is also elaborated. The performance of reproducing physiological blood pressure and wall shear stress is validated by both numerical characterization and flow experiment. Investigation of intracellular calcium ion dynamics in human umbilical vein endothelial cells is finally conducted to demonstrate the biological applicability of the proposed microfluidic system.


Asunto(s)
Técnicas de Cultivo de Célula , Microfluídica , Presión Sanguínea , Células Endoteliales de la Vena Umbilical Humana , Humanos , Resistencia al Corte , Estrés Mecánico
16.
Physiol Plant ; 171(1): 137-150, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32997341

RESUMEN

Many plants grown with low-millimolar concentration of NH4 + as a sole nitrogen source develop NH4 + -toxicity symptoms. To date, crucial molecular identities and a practical approach involved in the improvement of plant NH4 + -tolerance remain largely unknown. By phenotyping of upland cotton grown on varied nitrogen forms, we came across a phenomenon that caused sub-millimolar concentrations of urea (e.g., up 50 µM) to repress the growth inhibition of roots and whole plant cultivated in a NH4 + -containing nutrient solution. A growth-recovery assay revealed that the relief in NH4 + -inhibited growth required only a short-term exposure (≧12 h) of the roots to urea, implying that urea could elicit an internal signaling and be involved in antagonizing NH4 + -sensitivity. Intriguingly, split-root experiments demonstrated that low urea occurrence in one root-half could efficaciously stimulate not only supplied root but also the root-half grown in NH4 + -solution without urea, indicating the existence of urea-triggered local and systemic long-distance signaling. In the split-root experiment we also observed high arginase activity, strong arginine reduction and remarkable upregulation of polyamine biosynthesis-related genes (ADC1/2, SPDS and SPMS). Therefore, we suggest that external urea might serve as an effective cue (signal molecule) in an arginine-/polyamine-related process for ameliorating NH4 + -suppressed root growth, providing a novel aspect for deeper exploring and understanding plant NH4 + -tolerance.


Asunto(s)
Compuestos de Amonio , Señales (Psicología) , Gossypium , Nitrógeno , Raíces de Plantas , Urea/farmacología
17.
Hepatobiliary Pancreat Dis Int ; 20(5): 409-415, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34420885

RESUMEN

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a public health challenge and significant cause of morbidity and mortality worldwide. Early identification is crucial for disease intervention. We recently proposed a nomogram-based NAFLD prediction model from a large population cohort. We aimed to explore machine learning tools in predicting NAFLD. METHODS: A retrospective cross-sectional study was performed on 15 315 Chinese subjects (10 373 training and 4942 testing sets). Selected clinical and biochemical factors were evaluated by different types of machine learning algorithms to develop and validate seven predictive models. Nine evaluation indicators including area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve (AUPRC), accuracy, positive predictive value, sensitivity, F1 score, Matthews correlation coefficient (MCC), specificity and negative prognostic value were applied to compare the performance among the models. The selected clinical and biochemical factors were ranked according to the importance in prediction ability. RESULTS: Totally 4018/10 373 (38.74%) and 1860/4942 (37.64%) subjects had ultrasound-proven NAFLD in the training and testing sets, respectively. Seven machine learning based models were developed and demonstrated good performance in predicting NAFLD. Among these models, the XGBoost model revealed the highest AUROC (0.873), AUPRC (0.810), accuracy (0.795), positive predictive value (0.806), F1 score (0.695), MCC (0.557), specificity (0.909), demonstrating the best prediction ability among the built models. Body mass index was the most valuable indicator to predict NAFLD according to the feature ranking scores. CONCLUSIONS: The XGBoost model has the best overall prediction ability for diagnosing NAFLD. The novel machine learning tools provide considerable beneficial potential in NAFLD screening.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Estudios Transversales , Humanos , Aprendizaje Automático , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Estudios Retrospectivos , Ultrasonografía
18.
Int J Mol Sci ; 22(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668324

RESUMEN

FOXC1, a transcription factor involved in cell differentiation and embryogenesis, is demonstrated to be a negative regulator of Nanog in this study. FOXC1 is up-regulated in retinoic acid-induced differentiation of F9 Embryonal Carcinoma (EC) cells; furthermore, FOXC1 specifically inhibits the core pluripotency factor Nanog by binding to the proximal promoter. Overexpression of FOXC1 in F9 or knockdown in 3T3 results in the down-regulation or up-regulation of Nanog mRNA and proteins, respectively. In order to explain the mechanism by which FOXC1 inhibits Nanog expression, we identified the co-repressor HDAC2 from the FOXC1 interactome. FOXC1 recruits HDAC2 to Nanog promoter to decrease H3K27ac enrichment, resulting in transcription inhibition of Nanog. To the best of our knowledge, this is the first report that FOXC1 is involved in the epigenetic regulation of gene expression.


Asunto(s)
Células Madre de Carcinoma Embrionario/metabolismo , Factores de Transcripción Forkhead/metabolismo , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Histona Desacetilasa 2/metabolismo , Proteína Homeótica Nanog/genética , Regiones Promotoras Genéticas , Tretinoina/farmacología , Animales , Antineoplásicos/farmacología , Células Madre de Carcinoma Embrionario/efectos de los fármacos , Células Madre de Carcinoma Embrionario/patología , Epigénesis Genética , Factores de Transcripción Forkhead/genética , Células HEK293 , Histona Desacetilasa 2/genética , Humanos , Ratones , Células 3T3 NIH , Proteína Homeótica Nanog/metabolismo
19.
Angew Chem Int Ed Engl ; 60(16): 8744-8749, 2021 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-33538039

RESUMEN

An efficient electrochemical radical silyl-oxygenation of electron-deficient alkenes is demonstrated, which gives access to a variety of new highly functionalized silicon-containing molecules, including ß-silyl-cyanohydrin derivatives in good yields with excellent chemo- and regio-selectivity. This electrochemical radical silylation process conducts under mild conditions without the use of transition metal catalyst or chemical oxidant and exhibits a wide scope of substrate silanes with high functional-group tolerance. The ability to access silyl radicals using electrochemical Si-H activation offers new perspectives for the synthesis of valuable organosilicon compounds in a sustainable and green manner.

20.
Am J Orthod Dentofacial Orthop ; 157(5): 641-650, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32354437

RESUMEN

INTRODUCTION: Nonsurgical mandibular expansion has been increasingly performed in recent years because it can effectively expand the mandibular dental arch. However, many types of mandibular expanders have been used in previous studies. No relevant studies have compared the biomechanical responses of different designs of mandibular expansion appliances with screws. Therefore, the purpose of this study was to analyze the stress distribution and displacement of the dentoalveolar structures according to different designs of mandibular screw expanders. METHODS: Cone-beam computed tomography scans were used for 3-dimensional reconstruction of the mandibular finite element model. Four different designs of mandibular expanders, 1 removable expander (type A) and 3 fixed expanders (types B, C, and D), were added to the finite element models. Expanders were activated transversely for 0.2 mm. The initial tooth displacement and von Mises stress distribution were evaluated. RESULTS: All the expanders enlarged the arch dimensions. In types A and B, the stress was mainly concentrated in the region of the anterior teeth, along with greater tooth displacement, whereas in types C and D, greater stress and displacement occurred in the region of the posterior teeth. Type A showed the greatest amount of transverse displacement. Type D was more efficient in the region of the posterior teeth. CONCLUSIONS: Types A and B should be used with great caution in the clinic because of their incompatible expansion pattern. Type D is the recommended mandibular expansion appliance because of its appropriate expansion pattern.


Asunto(s)
Maxilar , Diseño de Aparato Ortodóncico , Fenómenos Biomecánicos , Simulación por Computador , Tomografía Computarizada de Haz Cónico , Análisis de Elementos Finitos , Mandíbula , Estrés Mecánico
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