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1.
Trends Genet ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38734482

RESUMO

Genome-wide association studies (GWASs) have identified numerous genetic loci associated with human traits and diseases. However, pinpointing the causal genes remains a challenge, which impedes the translation of GWAS findings into biological insights and medical applications. In this review, we provide an in-depth overview of the methods and technologies used for prioritizing genes from GWAS loci, including gene-based association tests, integrative analysis of GWAS and molecular quantitative trait loci (xQTL) data, linking GWAS variants to target genes through enhancer-gene connection maps, and network-based prioritization. We also outline strategies for generating context-dependent xQTL data and their applications in gene prioritization. We further highlight the potential of gene prioritization in drug repurposing. Lastly, we discuss future challenges and opportunities in this field.

2.
Aging (Albany NY) ; 16(6): 5601-5617, 2024 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-38535989

RESUMO

RNA modifications have been substantiated to regulate the majority of physiological activities in the organism, including the metabolism of reactive oxygen species (ROS), which plays an important role in cells. As for the effect of RNA modification genes on ROS metabolism in glioblastoma (GBM), it has not been studied yet. Therefore, this study aims to screen the RNA modification genes that are most related to ROS metabolism and explore their effects on the biological behavior of GBM in vitro. Here, an association between WTAP and ROS metabolism was identified by bioinformatics analysis, and WTAP was highly expressed in GBM tissue compared with normal brain tissue, which was confirmed by western blotting and immunohistochemical staining. When using a ROS inducer to stimulate GBM cells in the WTAP overexpression group, the ROS level increased more significantly and the expression levels of superoxide dismutase 1 (SOD1) and catalase (CAT) also increased. Next, colony formation assay, wound healing assay, and transwell assay were performed to investigate the proliferation, migration, and invasion of GBM cells. The results showed that WTAP, as an oncogene, promoted the malignant progression of GBM cells. Functional enrichment analysis predicted that WTAP was involved in the regulation of tumor/immune-related functional pathways. Western blotting was used to identify that WTAP had a regulatory effect on the phosphorylation of PI3K/Akt signaling. Finally, based on functional enrichment analysis, we further performed immune-related analysis on WTAP. In conclusion, this study analyzed WTAP from three aspects, which provided new ideas for the treatment of GBM.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/patologia , Espécies Reativas de Oxigênio/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Microambiente Tumoral/genética , Proliferação de Células/genética , Neoplasias Encefálicas/patologia , RNA , Linhagem Celular Tumoral , Fatores de Processamento de RNA , Proteínas de Ciclo Celular/metabolismo
3.
Aging (Albany NY) ; 16(2): 1555-1580, 2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-38240717

RESUMO

Genome-wide association studies (GWAS) have identified multiple risk variants for Parkinson's disease (PD). Nevertheless, how the risk variants confer the risk of PD remains largely unknown. We conducted a proteome-wide association study (PWAS) and summary-data-based mendelian randomization (SMR) analysis by integrating PD GWAS with proteome and protein quantitative trait loci (pQTL) data from human brain, plasma and CSF. We also performed a large transcriptome-wide association study (TWAS) and Fine-mapping of causal gene sets (FOCUS), leveraging joint-tissue imputation (JTI) prediction models of 22 tissues to identify and prioritize putatively causal genes. We further conducted PWAS, SMR, TWAS, and FOCUS using a multi-trait analysis of GWAS (MTAG) to identify additional PD risk genes to boost statistical power. In this large-scale study, we identified 16 genes whose genetically regulated protein abundance levels were associated with Parkinson's disease risk. We undertook a large-scale analysis of PD and correlated traits, through TWAS and FOCUS studies, and discovered 26 casual genes related to PD that had not been reported in previous TWAS. 5 genes (CD38, GPNMB, RAB29, TMEM175, TTC19) showed significant associations with PD at both the proteome-wide and transcriptome-wide levels. Our study provides new insights into the etiology and underlying genetic architecture of PD.


Assuntos
Doença de Parkinson , Transcriptoma , Humanos , Estudo de Associação Genômica Ampla , Proteoma/genética , Predisposição Genética para Doença , Doença de Parkinson/genética , Polimorfismo de Nucleotídeo Único , Glicoproteínas de Membrana/genética
4.
Chin J Traumatol ; 26(3): 147-154, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-35985904

RESUMO

PURPOSE: Child head injury under impact scenarios (e.g. falls, vehicle crashes, etc.) is an important topic in the field of injury biomechanics. The head of piglet was commonly used as the surrogate to investigate the biomechanical response and mechanisms of pediatric head injuries because of the similar cellular structures and material properties. However, up to date, piglet head models with accurate geometry and material properties, which have been validated by impact experiments, are seldom. We aim to develop such a model for future research. METHODS: In this study, first, the detailed anatomical structures of the piglet head, including the skull, suture, brain, pia mater, dura mater, cerebrospinal fluid, scalp and soft tissue, were constructed based on CT scans. Then, a structured butterfly method was adopted to mesh the complex geometries of the piglet head to generate high-quality elements and each component was assigned corresponding constitutive material models. Finally, the guided drop tower tests were conducted and the force-time histories were ectracted to validate the piglet head finite element model. RESULTS: Simulations were conducted on the developed finite element model under impact conditions and the simulation results were compared with the experimental data from the guided drop tower tests and the published literature. The average peak force and duration of the guide drop tower test were similar to that of the simulation, with an error below 10%. The inaccuracy was below 20%. The average peak force and duration reported in the literature were comparable to those of the simulation, with the exception of the duration for an impact energy of 11 J. The results showed that the model was capable to capture the response of the pig head. CONCLUSION: This study can provide an effective tool for investigating child head injury mechanisms and protection strategies under impact loading conditions.


Assuntos
Traumatismos Craniocerebrais , Crânio , Animais , Suínos , Análise de Elementos Finitos , Crânio/lesões , Traumatismos Craniocerebrais/diagnóstico por imagem , Encéfalo , Fenômenos Biomecânicos , Couro Cabeludo
5.
Science ; 376(6594): eabo3440, 2022 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-35549428

RESUMO

We analyze the results of Zhao et al. (Reports, 17 September 2021, p. 1363) with a focus on the mechanical properties and microstructural evolution. We conclude that their results, together with the explanations and interpretations, are confusing, misleading, or even wrong.

6.
Animals (Basel) ; 12(7)2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35405926

RESUMO

During the periparturient period, dairy cows suffer drastic metabolic stress because of plasma increased non-esterified fatty acids (NEFAs) that stem from a negative energy balance. Fibroblast growth factor 21 (FGF21) is a hepatokine that activates the AMP-activated protein kinase (AMPK) signaling pathway to maintain intracellular energy balance and tissue integrity via the promotion of catabolism and the inhibition of anabolic regulation. FGF21 treatment caused a 50% reduction in triglyceride (TG) content in liver in dairy cows. However, it is not clear whether FGF21 regulates lipid metabolism in bovine liver. The purpose of this study was to evaluate the influence of FGF21 on lipid metabolism via AMPK signaling in bovine hepatocytes. The hepatocytes isolated from calves were treated with different concentrations of FGF21 or co-treated with AMPK inhibitor (BML-275). Herein, the study showed that FGF21 significantly reduced TG content in a dose-response manner and promoted very-low-density lipoprotein (VLDL) secretion via an up-regulation of the proteins (ApoB 100, ApoE and MTTP) involved in VLDL secretion. Otherwise, the genes associated with lipid transport (LDLR and CD36) and lipid oxidation (PPARGC1A, ACOX1 and CPT1A), were up-regulated following FGF21 treatment. Moreover, FGF21 treatment inhibited lipogenesis via SREBF1, ACACA, FASN and ACLY inhibition. After being co-treated with the AMPK inhibitor, FGF21-induced changes were reversed in some genes. In conclusion, these results indicate that FGF21 adaptively regulates energy metabolism for a negative impact on lipogenesis, strengthens lipid oxidation, and inhibited lipid transportation via AMPK signaling in bovine hepatocytes. The present data suggest the possibility that FGF21 has potential value in alleviating perinatal metabolic diseases in dairy cows, and specific research in vivo should be studied in more detail.

7.
Comput Methods Programs Biomed ; 215: 106591, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34979294

RESUMO

BACKGROUND AND OBJECTIVE: Head injury is the leading cause of fatalities and disabilities in children. Characterizing the variation in cranial size/shape and thickness during growth is important for developing finite element models of child heads and evaluating head injury risk at different ages. However, the quantitative morphological features of the cranial vault (size/shape and non-uniform thickness distribution) have not been accounted for in children aged between 3 and 10 years old (YO). METHODS: Geometrically equivalent discrete points were identified on 42 head CT scans of 3-10 YO children by separation, curve dividing, and point fitting. Based on discrete points, the principal component analysis and regression (PCA&R) method was used to develop a statistical model of the cranial vault as a function of age and head circumference. RESULTS: The ontogeny of three-dimensional cranial morphology and non-uniform thickness from 3 to 10 years of age was quantified and cranial vault morphologies for 3-10 YO children were generated in 1 year intervals. CONCLUSIONS: The automatic method, the procedure of identifying discrete points from CT scans, and the developed quantitative cranial vault model are reliable and accurate.


Assuntos
Modelos Estatísticos , Crânio , Cefalometria , Criança , Pré-Escolar , China , Cabeça , Humanos , Lactente , Crânio/diagnóstico por imagem
8.
Immune Netw ; 22(6): e49, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36627935

RESUMO

Exosomes derived from mesenchymal stem cells (MSCs) could protect against myocardial infarction (MI). TLR4 is reported to play an important role in MI, while microRNA-182-5p (miR-182-5p) negatively regulates TLR4 expression. Therefore, we hypothesize that MSCs-derived exosomes overexpressing miR-182-5p may have beneficial effects on MI. We generated bone marrow mesenchymal stem cells (BM-MSCs) and overexpressed miR-182-5p in these cells for exosome isolation. H2O2-stimulated neonatal mouse ventricle myocytes (NMVMs) and MI mouse model were employed, which were subjected to exosome treatment. The expression of inflammatory factors, heart function, and TLR4 signaling pathway activation were monitored. It was found that miR-182-5p decreased TLR4 expression in BM-MSCs and NMVMs. Administration of exosomes overexpressing miR-182-5p to H2O2-stimulated NMVMs enhanced cell viability and suppressed the expression of inflammatory cytokines. In addition, they promoted heart function, suppressed inflammatory responses, and de-activated TLR4/NF-κB signaling pathway in MI mice. In conclusion, miR-182-5p transferred by the exosomes derived from BM-MSCs protected against MI-induced impairments by targeting TLR4.

9.
Front Pharmacol ; 12: 715285, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34447312

RESUMO

Swainsonine (SW), an indolizidine alkaloid extracted from locoweeds, was shown toxic effects in multiple studies, but the underlying action mechanism remains unclear. SW is known to cause autophagy and apoptosis, but there has been no report on paraptosis mediated cell death. Here, we showed that SW induced rat primary renal tubular epithelial cells (RTECs) death accompanied by vacuolation in vitro. The fluorescence with the endoplasmic reticulum (ER)-Tracker Red and transmission electron microscopy (TEM) results indicated that the vacuoles were of ER origin, typical of paraptosis. The level of ER stress markers, such as polyubiquitinated proteins, Bip, CHOP and cytoplasmic concentration of Ca2+ have drastically increased. Interestingly, autophagy inhibitor could not interrupt but enhanced the induction of cytoplasmic vacuolization. Furthermore, MAPK pathways were activated by SW and inhibitors of ERK and JNK pathways could prevent the formation of cytoplasmic vacuolization. In this study, we confirmed that SW induced cell paraptosis through ER stress and MAPK signaling pathway, thus further laying a theoretical foundation for the study of SW toxicity mechanism.

10.
Med Eng Phys ; 94: 41-50, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34303500

RESUMO

Child neck injuries in motor vehicle crashes (MVCs) result in high morbidity and mortality rates. Estimating a statistical cervical vertebrae geometric model and quantifying the variations of the size and shape with age are very important for investigating the dynamic response and injury risk to a child's cervical spine, as well as for providing a geometric basis for developing child anthropomorphic test devices (ATDs) and finite element models (FEMs) of different ages. In this study, spatial geometric points were automatically extracted from the cervical vertebrae computed tomography (CT) scans of 30 children aged 10 to 18 years old (YO), and a statistical geometric model was estimated for the cervical vertebrae as a function of age and neck circumference/neck length according to the method of principal component analysis and regression (PCA&R). Based on this statistical model, geometric point sets representing cervical vertebrae geometries at different ages and percentiles were generated and formed to envelope surfaces. Meanwhile, the size changes of the cervical vertebrae with child growth from 10 to 18 YO were quantified. In general, the anteroposterior length (APL), transverse process width (TPW), vertebral body height (VBH), and vertebral body depth (VBD) of the cervical vertebrae increase with age; the VBH and VBD increase faster than the APL and TPW. Compared with other vertebrae, the APL of C7 is larger, and the rate of increase of C1 with age is evidently slower. The TPWs of C1 and C7 are greater than those of C2 to C6. C7 has higher average values for the VBH and VBD than C3 to C6.


Assuntos
Vértebras Cervicais , Modelos Estatísticos , Adolescente , Estatura , Vértebras Cervicais/diagnóstico por imagem , Criança , Humanos , Tomografia Computadorizada por Raios X , Corpo Vertebral
11.
Front Pharmacol ; 12: 685895, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34108882

RESUMO

Monocrotaline (MCT), a pyrrolizidine alkaloid, is the major toxin in Crotalaria, which causes cell apoptosis in humans and animals. It has been reported that the liver is a vulnerable target of MCT. However, the exact molecular mechanism of the interaction between endoplasmic reticulum (ER) stress and liver injury induced by MCT is still unclear. In this study, the cytotoxicity of MCT on primary rat hepatocytes was analyzed by a CCK-8 assay and Annexin V-FITC/PI assay. Protein expression was detected by western blotting and immunofluorescence staining. As a result, MCT significantly decreased the cell viability and mediated the apoptosis of primary rat hepatocytes. Meanwhile, MCT could also induce ER stress in hepatocytes, indicated by the expression of ER stress-related proteins, including GRP78, p-IRE1α, ATF6, p-eIF2α, ATF4, and CHOP. Pretreatment with 4-PBA, an inhibitor of ER stress, or knockdown of CHOP by siRNA could partly enhance cell viability and relieve the apoptosis. Our findings indicate that ER stress is involved in the hepatotoxicity induced by MCT, and CHOP plays an important role in this process.

12.
Nanomaterials (Basel) ; 11(3)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33668939

RESUMO

The conventional engineering stress-strain curve could not accurately describe the true stress-strain and local deformability of the necking part of tensile specimens, as it calculates the strain by using the whole gauge length, assuming the tensile specimen was deformed uniformly. In this study, we employed 3D optical measuring digital image correlation (DIC) to systematically measure the full strain field and local strain during the whole tensile process, and calculate the real-time strain and actual flow stress in the necking region of ultrafine-grained (UFG) Ti. The post-necking elongation and strain hardening exponent of the UFG Ti necking part were then measured as 36% and 0.101, slightly smaller than those of the coarse grained Ti (52% and 0.167), suggesting the high plastic deformability in the necking part of the UFG Ti. Finite elemental modeling (FEM) indicates that when necking occurs, strain is concentrated in the necking region. The stress state of the necking part was transformed from uniaxial in the uniform elongation stage to a triaxial stress state. A scanning electron microscopic (SEM) study revealed the shear and ductile fracture, as well as numerous micro shear bands in the UFG Ti, which are controlled by cooperative grain boundary sliding. Our work revealed the large plastic deformability of UFG metals in the necking region under a complex stress state.

13.
Chem Biol Interact ; 336: 109319, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33186601

RESUMO

Swainsonine (SW), an indolizidine alkaloid, is the primary toxin in locoweeds that causes toxicity syndrome in livestock. Current research shows that SW can induce both apoptosis and autophagy. However, the relationship between, and regulatory mechanism of, autophagy and apoptosis in SW-mediated cytotoxicity remain unclear. In this study, we investigated the role of autophagy and apoptosis in SW-induced cytotoxicity in rat primary renal tubular epithelial cells (RTECs). We examined the effect of SW on lysosomal function using western blotting, transmission electron microscopy, fluorescent microscopy, and flow cytometry. The results showed that SW induced both autophagy and apoptosis, and autophagy protected RTECs from cellular damage. Activating autophagy using rapamycin (Rapa) inhibited apoptosis, while suppressing autophagy using bafilomycin A1 (Baf A1) greatly enhanced SW-induced apoptosis. SW treatment suppressed the expression of lysosomal-related proteins, and co-incubation with SW and aloxistatin (E64d) further promoted apoptosis and LC3-II accumulation in RTECs. These results suggest that SW causes toxicity by disrupting lysosomal dysfunction, inhibiting autophagic degradation, and promoting apoptosis.


Assuntos
Autofagia/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Túbulos Renais/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Swainsonina/farmacologia , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Túbulos Renais/metabolismo , Lisossomos/metabolismo , Conformação Molecular , Ratos , Relação Estrutura-Atividade , Swainsonina/química
14.
IUBMB Life ; 72(12): 2710-2721, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33205615

RESUMO

In dairy cows, fatty liver is one of the most common metabolic diseases that occurs during the periparturient period. Angiopoietin-like protein 4 (ANGPTL4) is a well-known downstream target of peroxisome proliferator-activated receptors (PPARs), which regulate the glucose and fatty acid metabolisms. The inhibition of lipoprotein lipase (LPL) activity interferes with the storage of triglycerides (TG) in adipocytes, which plays an essential role in lipid metabolism in rodents. However, it remains unclear whether ANGPTL4 is involved in the pathological process of fatty liver in dairy cows as a result of the regulation of the hepatocellular lipid transport system. This study intended to investigate the effect of ANGPTL4 on the very-low-density lipoprotein (VLDL) assembly and secretion in bovine hepatocytes. Bovine hepatocytes were isolated using a modified two-step perfusion and collagenase digestion process, and treated with different concentrations of ANGPTL4 (0, 4, 12, and 24 ng/ml) for 24 hr. The results showed that a high concentration of ANGPTL4 could significantly increase the extracellular concentration of VLDL while reducing the intracellular content of TG. Thus, it was confirmed that ANGPTL4 could promote the transport of TG in the form of VLDL by partially regulating the expression of related proteins in hepatocytes, thereby contributing to the partial adaptive regulation of lipid transport in dairy cows.


Assuntos
Proteína 4 Semelhante a Angiopoietina/metabolismo , Fígado Gorduroso/patologia , Hepatócitos/metabolismo , Lipoproteínas VLDL/metabolismo , Triglicerídeos/metabolismo , Proteína 4 Semelhante a Angiopoietina/genética , Animais , Bovinos , Fígado Gorduroso/metabolismo , Hepatócitos/citologia , Técnicas In Vitro
15.
Rev Sci Instrum ; 91(8): 081501, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32872966

RESUMO

The split Hopkinson bar (SHB) has been widely used for testing the dynamic mechanical behavior of materials. However, it is hard to involve complex stress conditions in traditional SHB due to its intrinsic characteristics. The Electromagnetic Hopkinson bar (E-Hopkinson bar) has been recently proposed as a solution. Different from the traditional SHB, the stress pulse of the E-Hopkinson bar is generated directly by the electromagnetic force. Therefore, the stress pulse that loads the specimen can be accurately controlled. With this advantage, some experiments that cannot be done with traditional SHB can be conducted by the E-Hopkinson bar technique. In this review, we introduced briefly the basic principles of the E-Hopkinson bar. Some lasted tests, such as symmetrically dynamic compression/tension of materials, interlaminar fracture of composites, dynamic Bauschinger effect of metals, intermediate strain rate tests, and dynamic multi-axial tests were also introduced. This new technique will be helpful for those researchers in the field of solid mechanics, especially when the strain rate and complex stress condition are involved.

16.
Res Vet Sci ; 130: 237-239, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32224353

RESUMO

Monocrotaline (MCT) belongs to the category of Pyrrolizdine Alkaloids (PAs), which is one of important hepatotoxic alkaloid in Crotalaria Lin. Apoptosis is one mechanism of toxic responses induced by MCT. However, the underlying mechanism of liver apoptosis caused by MCT through Endoplasmic reticulum (ER) stress continues to be incompletely understood. In this study, we describe the role of ER stress in MCT induced hepatotoxicity in rats. 24 male rats were randomly divided into 3 groups: normal saline group, 45 mg/kg MCT group and 90 mg/kg MCT group. After 48 h of saline/MCT administration, the livers were collected for analysis of ER stress-related proteins by Western blotting. The expression of GRP78, p-IRE1α, ATF6 and caspase-12 showed a dose-dependent increase. PERK/eIF2α/ATF4/CHOP pathway is one of the major ER stress pathways which is required for cell survival. Therefore, through analyzing the effects of MCT on this pathway, we found the protein levels of p-PERK, p-eIF2α, ATF4 and CHOP were increase obviously. All these results indicate that MCT induces ER stress in rat liver. The PERK/eIF2α/ATF4/CHOP pathway is involved in the regulation of MCT-induced ER stress in the liver of rat.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fígado/efeitos dos fármacos , Monocrotalina/efeitos adversos , Fator 4 Ativador da Transcrição/metabolismo , Animais , Fator de Iniciação 2 em Eucariotos/metabolismo , Fígado/fisiopatologia , Masculino , Ratos , Ratos Sprague-Dawley , Fator de Transcrição CHOP/metabolismo , eIF-2 Quinase/metabolismo
17.
J Food Sci ; 84(10): 3063-3068, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31524953

RESUMO

Alkylresorcinols are phenolic lipids that mainly exist in the cortex of grains, and they exhibit anticancer activity against various cancer cells in vitro. However, the underlying action mechanisms are still unclear. In our study, the influence of alkylresorcinols C19:0 and C21:0 (ARs) upon migration, invasion, and autophagy in human hepatoblastoma HepG2 cells was evaluated. Results showed that ARs at 80 and 160 µg/mL significantly suppressed cells proliferation, migration, and invasion, downregulated the expression of proteins RhoA and MMP-7 associated with migration and invasion. ARs at 160 µg/mL, the rate of LC3 puncta was appreciably increased. After autophagy was blocked by 3-MA or CQ, the expression of LC3II was significantly increased in 3-MA+ARs group and p62 was significantly decreased in CQ+ARs group. The results indicate that ARs may promote autophagic flow. ARs (80, 160 µg/mL) significantly inhibited the expression of proteins p-mTOR, p-PI3K, and p-Akt related to the PI3K/Akt pathway. The results of the present study suggest that ARs can activate autophagy and suppresses the biological behaviors of HepG2 cells by inhibiting the activation of MMP-7, Rho/Rho-associated protein kinase, and activation of the phosphatidylinositol 3-kinase/Akt signaling pathway. PRACTICAL APPLICATION: The anticancer mechanism of ARs in wheat bran was studied, which provided a basis for the development of anticancer functional auxiliary food with wheat bran as raw material. It is of great practical significance to promote the effective utilization of grain processing by-products and improve the economic benefits of the grain industry.


Assuntos
Autofagia/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Resorcinóis/farmacologia , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Hep G2 , Humanos , Estrutura Molecular , Fosfatidilinositol 3-Quinase/genética , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Resorcinóis/química , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
18.
Phys Rev Lett ; 122(1): 015503, 2019 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31012723

RESUMO

One of the most important issues related to adiabatic shear failure is the correlation among temperature elevation, adiabatic shear band (ASB) formation and the loss of load capacity of the material. Our experimental results show direct evidence that ASB forms several microseconds after stress collapse and temperature rise reaches its maximum about 30 µs after ASB formation. This observation indicates that temperature rise cannot be the cause of ASB. Rather, it might be the result of adiabatic shear localization. As such, the traditional well-accepted thermal-softening mechanism of ASB needs to be reconsidered.

19.
J Mol Neurosci ; 67(4): 622-631, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30719640

RESUMO

Lipid peroxidation plays a crucial role in early brain injury (EBI) after subarachnoid hemorrhage (SAH), and cystine/glutamate antiporter system Xc- has been proved to be associated with glutathione (GSH) synthesis, which protects cells against oxidative damage. Antioxidant effect of system Xc- is mediated by Beclin 1 (BECN1). Therefore, this study aimed to determine whether administration of BECN1 small interfering RNA (siRNA) could attenuate EBI after SAH experiment, specifically through suppressing lipid peroxidation and increasing system Xc- activity. Endovascular perforation was performed to induce SAH in a rat model and BECN1 siRNA was administered through intracerebroventricular injection. Neurological score, brain edema, lipid peroxidation (malondialdehyde, MDA), and antioxidation system, containing GSH, glutathione peroxidase (GSH-Px), glutathione reductase (GR), and anti-reactive oxygen species (anti-ROS), were examined. The expression of BECN1 and light chain of system Xc- (xCT) was detected by western blot, immunoprecipitation, and immunofluorescence staining. This study confirmed that SAH induced neurological deficits and brain edema, which was accompanied by the increase of BECN1 expression and lipid peroxidation, and the decrease of xCT expression and antioxidative capacity. However, downregulation of BECN1 by siRNA could decrease the formation of the BECN1-xCT complex and lipid peroxidation, enhance antioxidative capacity, and ameliorate neurological deficits and brain edema in SAH rats. The results suggested that inhibition of BECN1 suppresses accumulation of lipid peroxidation by increasing system Xc- activity in EBI after SAH, and BECN1 may be a new effective target for EBI treatment after SAH.


Assuntos
Sistema y+ de Transporte de Aminoácidos/metabolismo , Proteína Beclina-1/genética , Peroxidação de Lipídeos , Terapêutica com RNAi/métodos , Hemorragia Subaracnóidea/terapia , Animais , Proteína Beclina-1/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Masculino , Ratos , Ratos Sprague-Dawley
20.
ACS Biomater Sci Eng ; 5(8): 4122-4130, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-33448813

RESUMO

The aim of this in vitro and in vivo study was to evaluate the fracture strength and osseointegration of an ultrafine-grained pure titanium (UFG-Ti) mini dental implant, prepared by equal channel angular pressing (ECAP) after macro-morphology optimization. UFG-Ti was prepared by ECAP using four passes in route Bc with the internal channel angle of 120° at room temperature. Furthermore, its microstructure and mechanical properties were studied. In optimization, a three-dimensional finite element model (FEM) composed of an UFG-Ti mini implant and alveolar bone was established to improve the implant surface area and decrease the stress distribution. Then, optimized mini implants were fabricated using UFG-Ti, and a fracture strength test was performed. For the in vivo study, UFG-Ti mini implants were inserted into rabbit femurs. A histological assessment and a pull-out test were performed to evaluate its osseointegration ability. The results show that the ultimate tensile strength of UFG-Ti (685 ± 35 MPa) was significantly higher than that of commercial pure titanium (CP-Ti grade 4, 454 ± 27 MPa). After optimization, the surface area of the 2.5 mm diameter mini implant was 19% higher than that of the standard-thread mini implant, and the maximum equivalent stress (Max EQV stress) decreased by 28% in cortical bone and by 33.1% in cancellous bone, when the thread height was 0.3 mm and the pitch was 0.67 mm. The fracture strength of the UFG-Ti mini implants (328 ± 21 N) was significantly higher than that of CP-Ti grade 4 mini implants (197 ± 11 N). The in vivo study showed favorable osseointegration in both the UFG-Ti and CP-Ti groups, but the osseointegration strength of the optimized mini implants was higher than that of the standard-thread mini implants. In conclusion, the fracture and osseointegration strength had been significantly improved for UFG-Ti mini dental implant after optimization. The excellent mechanical properties and osseointegration of the UFG-Ti mini implant suggest its feasibility for clinical application.

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