Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Cell Biol Toxicol ; 40(1): 59, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39060559

RESUMO

Acute liver injury (ALI) is a common life-threatening condition with a high mortality rate due to liver disease-related death. However, current therapeutic interventions for ALI remain ineffective, and the development of effective novel therapies is urgently needed. Liver samples from patients with drug-induced ALI were collected to detect adenosine kinase (ADK) expression. Male C57BL/6 J mice, hepatocyte-specific ADK knockout (ADKHKO) mice, and their controls (ADKf/f) were exposed to acetaminophen (APAP) and other treatments to investigate the mechanisms of APAP-related ALI. ADK expression was significantly decreased in APAP-injured livers. Hepatocyte-specific ADK deficiency exacerbated APAP-induced ALI, while a gain-of-function approach delivering AAV-ADK, markedly alleviated APAP-induced ALI, as indicated by changes in alanine aminotransferases (ALT) levels, aspartate aminotransferase (AST) levels, neutrophil infiltration and hepatocyte death. This study showed that ADK played a critical role in ALI by activating autophagy through two signaling pathways, the adenosine monophosphate-activated protein kinase (AMPK)-mTOR pathway and the adenosine receptor A1 (ADORA1)-Akt-mTOR pathway. Furthermore, we found that metformin upregulated ADK expression in hepatocytes and protected against APAP-induced ALI. These results demonstrate that ADK is critical in protecting against APAP-induced ALI and that developing therapeutics targeting ADK-adenosine-ADORA1 is a new approach for ALI treatment. Metformin is a potential candidate for preventing ALI by upregulating ADK.


Assuntos
Acetaminofen , Adenosina Quinase , Autofagia , Doença Hepática Induzida por Substâncias e Drogas , Hepatócitos , Transdução de Sinais , Animais , Humanos , Masculino , Camundongos , Acetaminofen/efeitos adversos , Adenosina Quinase/metabolismo , Adenosina Quinase/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Autofagia/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Hepatócitos/metabolismo , Hepatócitos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
2.
Artigo em Inglês | MEDLINE | ID: mdl-38758145

RESUMO

Objective: This study aims to compare the therapeutic efficacy of laparoscopic right-lower quadrant and midline approaches for the treatment of right-sided colon cancer and evaluate the analgesic effect of parecoxib sodium. Methods: Sixty patients with right-sided colon cancer admitted to Hospital of Lin 'an District between January 2019 and November 2022 were selected. They were divided into the study group A (n=30) with a right-lower quadrant approach and the study group B (n=30) with a midline approach. All patients received parecoxib sodium. Surgical time, blood loss, postoperative complications, and other relevant indicators were recorded and compared between the two groups. Additionally, a control group of 60 right-sided colon cancer patients who underwent conventional non-exclusive analgesic laparoscopic surgery during the same period was included to compare the analgesic effects between the study and control groups. Results: The surgical time (RR = 0.608, 95%CI 0.51, 1.53, P = .042), blood loss (RR = 0.798, 95%CI 0.52, 1.02, P < .001), time for bowel function recovery (RR = 0.808, 95%CI 0.50, 1.77, P = .007), and length of hospital stay (RR = 0.766, 95%CI 0.56, 1.72, P =.052) were significantly lower in group A than in group B, while the number of lymph node dissections was higher in group A (RR = 0.803, 95%CI 0.62, 1.52, P = .047). The postoperative levels of tumor-specific growth factor (TSGF) (RR = 0.710, 95%CI 0.50, 1.55, P < .001) and carcinoembryonic antigen (CEA) (RR = 0.803, 95%CI 0.62, 1.52, P < .001) were significantly decreased in both groups A and B, with no significant difference between the groups (P > .05). The incidence of complications in group A was significantly lower than in group B (RR = 0.167, 95%CI 0.17, 0.63, P = .044). The VAS scores of the study group at 2/4/6/8 hours postoperatively were significantly lower than those of the control group (RR = 0.702, 95%CI 0.52, 1.62, P < .001). The SF-36 scores of the study group were significantly higher than those of the control group (RR = 0.753, 95%CI 0.56, 1.82, P < .001). Conclusions: The Laparoscopic right-lower quadrant approach for the treatment of right-sided colon cancer offers advantages such as shorter surgical time and less blood loss. It demonstrates significant clinical efficacy and reduces the incidence of postoperative complications. Parecoxib sodium enhances postoperative analgesic effect, effectively alleviating patient pain, promoting recovery, and improving quality of life. It is worth promoting in clinical practice.

3.
Front Cell Dev Biol ; 10: 827714, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281076

RESUMO

Background: Inflammatory disorder and acinar cell death contribute to the initiation and progression of severe acute pancreatitis (SAP). Adenosine kinase (ADK) has potential effects on both inflammation and cell death. However, the role of ADK in SAP remains to be explored. Methods: To establish an experimental SAP model, male C57BL/6 mice were intraperitoneally injected with cerulein (50 µg/kg, seven doses at hourly intervals) and LPS (10 mg/kg, at the last cerulein injection). For ADK inhibition, ABT702 (1.5 mg/kg) was intraperitoneally injected 1 h before cerulein treatment. The pancreas and serum were collected and analyzed to determine the severity of pancreatic injury and explore the potential pathophysiological mechanisms. Pancreatic acinar cells (AR42J) were used to explore the in vitro effects of ADK inhibition on cerulein-induced inflammation and necroptotic cell death. Results: ADK inhibition notably attenuated the severity of SAP, as indicated by the decreased serum amylase (7,416.76 ± 1,457.76 vs. 4,581.89 ± 1,175.04 U/L) and lipase (46.51 ± 11.50 vs. 32.94 ± 11.46 U/L) levels and fewer pancreatic histopathological alterations (histological scores: 6.433 ± 0.60 vs. 3.77 ± 0.70). MOMA-2 and CD11b staining confirmed that ADK inhibition prevented the infiltration of neutrophils and macrophages. The phosphorylation of nuclear factor-κB (NF-κB) was also reduced by ADK inhibition. ADK inhibition markedly limited the necrotic area of the pancreas and prevented the activation of the necroptotic signaling pathway. Endoplasmic reticulum (ER) stress was activated in the pancreas using the SAP model and cerulein-treated AR42J cells whereas ADK inhibition reversed the activation of ER stress both in vivo and in vitro. Moreover, the alleviating effects of ADK inhibition on ER stress, inflammation, and cell necroptosis were eliminated by the adenosine A2A receptor antagonist. Conclusion: ADK inhibition reduced inflammation and necroptotic acinar cell death in SAP via the adenosine A2A receptor/ER stress pathway, suggesting that ADK might be a potential therapeutic target for SAP.

4.
Cell Cycle ; 21(2): 187-201, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34919014

RESUMO

The present study aimed to investigate the role of neohesperidin (NH) in mice with steroid-induced femoral head necrosis (SONFH) and in bone marrow stromal cells (BMSCs). The SONFH model was established. The effects of NH on SONFH mice were detected by hematoxylin-eosin (HE) staining and micro-CT, while those on proliferation, osteogenic differentiation and associated pathways of BMSCs were detected by molecular experiments. Besides, the effects of NH on ß-catenin nuclear translocation and the H3K27me3 abundance on the transcriptional start site of Bone Morphogenetic Protein 2 (BMP2) were also determined by immunofluorescence staining and Chromatin Immunoprecipitation. Results indicated that NH not only reduced histopathological changes and improved the structures of the femoral heads of the SONFH mice but also promoted the proliferation and osteogenic differentiation of mouse BMSCs, enhanced alkaline phosphatase (ALP) activity, and upregulated expressions of osteoblast markers in a dose-dependent manner. Moreover, NH was also confirmed to upregulate the expressions of genes related to osteogenesis and Wnt/ß-catenin pathway of BMSCs, which, however, were all noticeably downregulated by Noggin and DKK1. Additionally, Noggin and DKK1 in combination further promoted the suppressive effect on genes related to osteogenesis and Wnt/ß-catenin pathway than alone. Besides, NH induced nuclear translocation of ß-catenin in BMSCs and further reduced H3K27me3-triggered enrichment of BMP2. In conclusion, NH could promote proliferation and osteogenic differentiation of BMSCs via BMP2-Wnt/ß-catenin pathway.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Animais , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Diferenciação Celular/genética , Proliferação de Células , Células Cultivadas , Hesperidina/análogos & derivados , Histonas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Camundongos , Osteogênese/genética , Via de Sinalização Wnt , beta Catenina/metabolismo
5.
Elife ; 102021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34569938

RESUMO

Apico-basal polarization of cells within the embryo is critical for the segregation of distinct lineages during mammalian development. Polarized cells become the trophectoderm (TE), which forms the placenta, and apolar cells become the inner cell mass (ICM), the founding population of the fetus. The cellular and molecular mechanisms leading to polarization of the human embryo and its timing during embryogenesis have remained unknown. Here, we show that human embryo polarization occurs in two steps: it begins with the apical enrichment of F-actin and is followed by the apical accumulation of the PAR complex. This two-step polarization process leads to the formation of an apical domain at the 8-16 cell stage. Using RNA interference, we show that apical domain formation requires Phospholipase C (PLC) signaling, specifically the enzymes PLCB1 and PLCE1, from the eight-cell stage onwards. Finally, we show that although expression of the critical TE differentiation marker GATA3 can be initiated independently of embryo polarization, downregulation of PLCB1 and PLCE1 decreases GATA3 expression through a reduction in the number of polarized cells. Therefore, apical domain formation reinforces a TE fate. The results we present here demonstrate how polarization is triggered to regulate the first lineage segregation in human embryos.


Assuntos
Padronização Corporal , Diferenciação Celular , Linhagem da Célula , Polaridade Celular , Embrião de Mamíferos/enzimologia , Actinas/metabolismo , Adulto , Técnicas de Cultura Embrionária , Feminino , Fator de Transcrição GATA3/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Humanos , Fosfoinositídeo Fosfolipase C , Fosfolipase C beta , Gravidez , Transdução de Sinais , Fatores de Tempo , Adulto Jovem
6.
Cell Cycle ; 20(19): 1953-1966, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34455928

RESUMO

Neohesperidin (NH) was reported to regulate osteoclastic differentiation, while LncRNA SNHG1 could inhibit osteogenic differentiation of bone marrow stromal cells (BMSCs). In this study, we aimed to explore whether SNHG1-mediated osteogenic differentiation could be regulated by NH. Osteonecrosis and adjacent tissues, as well as normal bone marrow samples were gathered. BMSCs were isolated from normal bone marrow samples by Ficoll density gradient and identified by flow cytometry. Histopathological changes of tissues were detected by hematoxylin-eosin staining. After the treatment with NH or transfection, cell viability, osteogenic differentiation, and the activity of alkaline phosphatase (ALP) in BMSCs were detected by MTT, alizarin red staining, and microplate method, respectively. The histone modification and expressions of SNHG1 and osteogenic marker genes in tissues or BMSCs were detected by q-PCR and Chromatin Immunoprecipitation (ChIp). SNHG1 was highly expressed in osteonecrosis tissues, and typical signs of empty lacunae appeared in the necrotic tissues zone. NH increased viability and osteogenic differentiation of BMSCs, activity of ALP, and expressions of RUNX2, OCN and ALP. NH decreased both SNHG1 expression and H3K4me3 (activating histone modification) occupancies and increased H3K27me3 (inhibiting histone modification) occupancies of SNHG1. Furthermore, siSNHG1 enhanced osteogenic differentiation of BMSCs and expressions of RUNX2, OCN and ALP, while SNHG1 overexpression did the opposite and reversed the effects of NH on the osteogenic differentiation of BMSCs. In a word, NH promotes the osteogenic differentiation of human BMSCs by inhibiting the histone modifications of lncRNA SNHG1.


Assuntos
Diferenciação Celular , Hesperidina , Células-Tronco Mesenquimais , Osteogênese , RNA Longo não Codificante , Células da Medula Óssea/citologia , Células Cultivadas , Hesperidina/análogos & derivados , Hesperidina/farmacologia , Código das Histonas , Humanos , Células-Tronco Mesenquimais/citologia , Osteogênese/genética , RNA Longo não Codificante/genética
7.
J Cell Mol Med ; 25(6): 2931-2943, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33523568

RESUMO

Increased adenosine helps limit infarct size in ischaemia/reperfusion-injured hearts. In cardiomyocytes, 90% of adenosine is catalysed by adenosine kinase (ADK) and ADK inhibition leads to higher concentrations of both intracellular adenosine and extracellular adenosine. However, the role of ADK inhibition in myocardial ischaemia/reperfusion (I/R) injury remains less obvious. We explored the role of ADK inhibition in myocardial I/R injury using mouse left anterior ligation model. To inhibit ADK, the inhibitor ABT-702 was intraperitoneally injected or AAV9 (adeno-associated virus)-ADK-shRNA was introduced via tail vein injection. H9c2 cells were exposed to hypoxia/reoxygenation (H/R) to elucidate the underlying mechanisms. ADK was transiently increased after myocardial I/R injury. Pharmacological or genetic ADK inhibition reduced infarct size, improved cardiac function and prevented cell apoptosis and necroptosis in I/R-injured mouse hearts. In vitro, ADK inhibition also prevented cell apoptosis and cell necroptosis in H/R-treated H9c2 cells. Cleaved caspase-9, cleaved caspase-8, cleaved caspase-3, MLKL and the phosphorylation of MLKL and CaMKII were decreased by ADK inhibition in reperfusion-injured cardiomyocytes. X-linked inhibitor of apoptosis protein (XIAP), which is phosphorylated and stabilized via the adenosine receptors A2B and A1/Akt pathways, should play a central role in the effects of ADK inhibition on cell apoptosis and necroptosis. These data suggest that ADK plays an important role in myocardial I/R injury by regulating cell apoptosis and necroptosis.


Assuntos
Adenosina Quinase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Traumatismo por Reperfusão Miocárdica/metabolismo , Animais , Apoptose/efeitos dos fármacos , Biomarcadores , Gerenciamento Clínico , Modelos Animais de Doenças , Suscetibilidade a Doenças , Camundongos , Mitocôndrias/efeitos dos fármacos , Morfolinas/farmacologia , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/etiologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Necroptose/efeitos dos fármacos , Pirimidinas/farmacologia , Ratos , Espécies Reativas de Oxigênio/metabolismo
8.
J Biomed Mater Res B Appl Biomater ; 108(3): 990-999, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31369700

RESUMO

Glucosamine (GlcN) has been widely used to reduce joint pain and osteoarthritis progression, but the efficacy of GlcN remains controversial because of the low GlcN concentration reaching the articular cavity. The aim of this study is to provide an effective approach of GlcN delivery to a target site using photocrosslinkable methacrylated gelatin (GelMA)-based hydrogels, where GlcN could be gradually released during the degradation of the GelMA hydrogel. Herein, GlcN was acrylated as the acryloyl glucosamine (AGA) and covalently grafted to GelMA, and more than 87.7% of 15% (w/v) GelMA hydrogel was grafted with AGA. Moreover, in vitro outgrowth and apoptosis assay of bone marrow stem cells (BMSCs) demonstrated that the GelMA-AGA hydrogels had better biocompatibility, larger cell attachment, and higher cell viability than pure GlcN and AGA materials. Also, 15% (w/v) GelMA-AGA hydrogel was injected into the defect site for in vivo rabbit cartilage repair. Compared with oral administration of pure GlcN and injection of pure GelMA, the repaired cartilages using GelMA-AGA hydrogels had the smoothest surface of the defect site, filling more than 95% defect bulk. The similar content of glycosaminoglycans to the native tissue and the maximum amount of type II collagen was found in the repaired cartilage using GelMA-AGA hydrogels, indicating the outgrowth of hyaline cartilage.


Assuntos
Materiais Biocompatíveis/química , Cartilagem/efeitos dos fármacos , Gelatina/química , Glucosamina/química , Hidrogéis/química , Animais , Apoptose , Células da Medula Óssea/citologia , Osso e Ossos , Cartilagem/metabolismo , Proliferação de Células , Força Compressiva , Reagentes de Ligações Cruzadas/química , Matriz Extracelular/metabolismo , Cartilagem Hialina/química , Técnicas In Vitro , Masculino , Teste de Materiais , Metacrilatos/química , Fotoquímica , Coelhos , Reologia , Células-Tronco/citologia , Estresse Mecânico , Engenharia Tecidual , Alicerces Teciduais
9.
Biochem Biophys Res Commun ; 504(4): 777-783, 2018 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-30217444

RESUMO

Aldehyde dehydrogenase 2 (ALDH2) plays essential roles in drinking-associated diseases or effects. As we have previously reported, ALDH2 mediates acute ethanol-induced eNOS activation in vitro. However, whether chronic ethanol treatment has a dose-response endothelial protection, as well as the possible mediating role of ALDH2 involved, is unclear. Here, we show that appropriate dose of ethanol preserved the expression and activity of ALDH2 and eNOS, and alleviated senescence-associated phenotypes in human aortic endothelial cells. Furthermore, ALDH2 deficiency impairs the dose-response protection of ethanol against endothelial senescence by promoting the accumulation of 4-HNE, the formation of 4-HNE-SIRT1 protein adducts and the subsequent decrease in SIRT1-dependent p53 deacetylation. Collectively, our data indicate that ALDH2 mediates the protection of appropriate ethanol by modulating SIRT1/p53-dependent endothelial senescence.


Assuntos
Aldeído-Desidrogenase Mitocondrial/metabolismo , Células Endoteliais/efeitos dos fármacos , Etanol/toxicidade , Sirtuína 1/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Acetilação , Aldeído-Desidrogenase Mitocondrial/genética , Aorta/citologia , Células Cultivadas , Senescência Celular , Relação Dose-Resposta a Droga , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Humanos , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Transporte Proteico/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Sirtuína 1/genética , Testes de Toxicidade Crônica
10.
Sci Rep ; 7(1): 11574, 2017 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-28912491

RESUMO

The developmental capacity of in vitro matured oocytes is inferior to that of the in vivo matured ones due to insufficient cytoplasmic maturation. Although great efforts were made to accomplish better cytoplasmic maturation by meiotic arrest maintenance (MAM) before in vitro maturation (IVM), limited progress has been achieved in various species. This study showed that MAM of porcine oocytes was better achieved with roscovitine than with dibutyryl cyclic adenosine monophosphate (db-cAMP) or 3-isobutyl-1-methylxanthine. Oocyte developmental competence after IVM was significantly improved following MAM in 199 + FF medium (TCM-199 containing 10% porcine follicular fluid and 25 µM roscovitine) to a level even higher than that in control oocytes matured without pre-MAM. Observations on other markers further confirmed the positive effects of MAM in 199 + FF on oocyte cytoplasmic maturation. During MAM culture in 199 + FF, re-decondensation (RDC) of condensed chromatin occurred, and transcription of genes beneficial to cytoplasmic maturation was evident in some of the oocytes with surrounded nucleoli (SN). However, MAM with db-cAMP neither induced RDC nor improved oocyte developmental potential. Together, the results suggest that MAM in the presence of FF and roscovitine improved the developmental competence of porcine oocytes by promoting a pre-GVBD chromatin de-condensation and expression of beneficial genes.


Assuntos
Líquido Folicular/metabolismo , Heterocromatina/genética , Meiose/efeitos dos fármacos , Meiose/genética , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Roscovitina/farmacologia , Transcrição Gênica/efeitos dos fármacos , 1-Metil-3-Isobutilxantina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Cálcio/metabolismo , Feminino , Glutationa/metabolismo , Técnicas de Maturação in Vitro de Oócitos , Espécies Reativas de Oxigênio/metabolismo , Suínos
11.
Zhonghua Zhong Liu Za Zhi ; 37(6): 431-5, 2015 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-26463146

RESUMO

OBJECTIVE: To investigate the value of the liquid-based cytology (LBC) of brushing specimens obtained via fiberoptic bronchoscopy for clinical diagnosis of lung cancer. METHODS: We retrospectively analyzed the LBC cases in our hospital from January 2011 to May 2012, and evaluate its role in the diagnosis of lung cancer. RESULTS: The clinical data of a total of 4 380 cases were reviewed and 3 763 of them had histopathological or clinical follow-up results (including 3 306 lung cancer cases and 457 benign lesion cases). The sensitivity, specificity, and accuracy of LBC diagnosis for lung cancer were 72.4% (2 392/3 306), 99.3% (454/457) and 75.6% (2 846/3 763), respectively. Of the 1 992 lung cancer cases diagnosed by brushing LBC, 528 cases (26.5%) were failed to take forceps biopsy and 113 cases (5.7%) showed negative forceps biopsy results. The accurate rate of subtyping of LBC for non-small cell carcinoma and small cell carcinoma was 99.0% (1 487/1 502) (P < 0.001). Take the resection histopathology as gold standard, the accurate rates of subtyping squamous cell carcinoma, adenocarcinoma and small cell carcinoma by LBC were 95.6% (351/367), 95.6% (351/367) and 100% (367/367), respectively, (P < 0.001). The accurate rates of subtyping of squamous cell carcinoma, adenocarcinoma and small cell carcinoma by forceps biopsy were 97.0% (293/302), 97.4% (294/302) and 99.7% (301/302), respectively, (Kappa = 0.895, P < 0.001). There was no significant difference in subtyping respectively between forceps biopsy and brushing LBC (P > 0.05). CONCLUSIONS: Fiberoptic bronchoscopic brushing liquid-based cytology can significantly improve the detection rate of lung cancer, and have a high specificity and accurate rate of subtyping. It is an effective tool for the diagnosis and subtyping of lung cancer.


Assuntos
Adenocarcinoma/patologia , Broncoscopia/métodos , Carcinoma de Células Pequenas/patologia , Carcinoma de Células Escamosas/patologia , Neoplasias Pulmonares/patologia , Carcinoma de Pequenas Células do Pulmão/patologia , Biópsia/instrumentação , Biópsia/métodos , Brônquios , Carcinoma Pulmonar de Células não Pequenas/patologia , Humanos , Estudos Retrospectivos , Sensibilidade e Especificidade , Instrumentos Cirúrgicos
12.
Sci Rep ; 5: 11728, 2015 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-26122728

RESUMO

Conventional metals are routinely hardened by grain refinement or by cold working with the expense of their ductility. Recent nanostructuring strategies have attempted to evade this strength versus ductility trade-off, but the paradox persists. It has never been possible to combine the strength reachable in nanocrystalline metals with the large uniform tensile elongation characteristic of coarse-grained metals. Here a defect engineering strategy on the nanoscale is architected to approach this ultimate combination. For Nickel, spread-out nanoscale domains (average 7 nm in diameter) were produced during electrodeposition, occupying only ~2.4% of the total volume. Yet the resulting Ni achieves a yield strength approaching 1.3 GPa, on par with the strength for nanocrystalline Ni with uniform grains. Simultaneously, the material exhibits a uniform elongation as large as ~30%, at the same level of ductile face-centered-cubic metals. Electron microscopy observations and molecular dynamics simulations demonstrate that the nanoscale domains effectively block dislocations, akin to the role of precipitates for Orowan hardening. In the meantime, the abundant domain boundaries provide dislocation sources and trapping sites of running dislocations for dislocation multiplication, and the ample space in the grain interior allows dislocation storage; a pronounced strain-hardening rate is therefore sustained to enable large uniform elongation.

13.
Sci Rep ; 5: 8683, 2015 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-25731893

RESUMO

Although previous studies have suggested that cumulus cells (CCs) accelerate oocyte aging by secreting soluble and heat-sensitive paracrine factors, the factors involved are not well characterized. Because Fas-mediated apoptosis represents a major pathway in induction of apoptosis in various cells, we proposed that CCs facilitate oocyte aging by releasing soluble Fas ligand (sFasL). In this study, we reported that when the aging of freshly ovulated mouse oocytes were studied in vitro, both the apoptotic rates of CCs and the amount of CCs produced sFasL increased significantly with the culture time. We found that oocytes expressed stable levels of Fas receptors up to 24 h of in vitro aging. Moreover, culture of cumulus-denuded oocytes in CCs-conditioned CZB medium (CM), in CZB supplemented with recombinant sFasL, or in CM containing sFasL neutralizing antibodies all showed that sFasL impaired the developmental potential of the oocytes whereas facilitating activation and fragmentation of aging oocytes. Furthermore, CCs from the FasL-defective gld mice did not accelerate oocyte aging due to the lack of functional FasL. In conclusion, we propose that CCs surrounding aging oocytes released sFasL in an apoptosis-related manner, and the released sFasL accelerated oocyte aging by binding to Fas receptors.


Assuntos
Células do Cúmulo/metabolismo , Proteína Ligante Fas/metabolismo , Oócitos/metabolismo , Animais , Anticorpos Neutralizantes/farmacologia , Apoptose/efeitos dos fármacos , Comunicação Celular , Células Cultivadas , Senescência Celular , Meios de Cultivo Condicionados/farmacologia , Células do Cúmulo/efeitos dos fármacos , Proteína Ligante Fas/antagonistas & inibidores , Feminino , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Knockout , Oócitos/efeitos dos fármacos , Transdução de Sinais
14.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 13(4): 584-8, 2005 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-16129039

RESUMO

To explore the mechanism of iron metabolism and its regulation as well as the roles of IRP(2) in ion metabolism of HL-60 cells, HL-60 cells were cultured in RPMI 1640 medium supplemented with 10% heat-inactivated fetal bovine serum, which was treated with ferric chloride (FeCl(3)) or deferoxamine (DFO). The cells were harvested at 12, 24 and 48 hours of proliferation, and total RNA was isolated; cDNA was synthesized by reverse transcription (RT), and relative expression levels of IRP(2) mRNA, Fn mRNA and TfR mRNA were determined by RT-PCR. The results showed at follows: (1) the level of IRP(2) mRNA remained constant in all cells, whether or not treated with DFO or FeCl(3). However, the expression of IRP(2) mRNA decreased when the time of cell culture was prolonged. There was no significant difference between groups (F(B-S) = 1.199, P > 0.05), but there was significant difference among the different time culture (F(W-S) = 43.418, P < 0.01). (2) Cells which treated neither with DFO nor ferri chloride showed significant difference from the control (F(W-S) = 7.184, F(B-S) = 113.926; P < 0.01). The level of TfR mRNA increased in the cells treated with DFO. Surprisingly, when cells treated with FeCl(3), there was not decline of TfR mRNA expression, but it increased lightly at 12 hours and peaked at 24 hours and declined drastically at 48 hours. (3) The level of Fn mRNA in the cells treated with FeCl(3) was approximately 2-fold as the control cells. In contrast with the control cells, there was significant difference (P < 0.05). The level of Fn mRNA of the cells treated with DFO had little change. As compared with the control cells, no significant difference was seen (P > 0.05). (4) There was not any significant correlation between IRP(2) mRNA and TfR mRNA or Fn mRNA in HL-60 cells (r = -0.005; r = 0.074; P > 0.05). It is concluded that (1) IRP(2) may regulate the iron metabolism in HL-60 cells by altering amounts of the IRP(2) 3.7- or 6.4-kb mRNA at the transcriptional level, or by IRP(2) degradation at the post transcriptional level. (2) Both of Fn mRNA and TfR mRNA participated, more or less, in the iron metabolism in HL-60 cells.


Assuntos
Ferritinas/genética , Regulação Neoplásica da Expressão Gênica , Proteína 2 Reguladora do Ferro/genética , Receptores da Transferrina/genética , Células HL-60 , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA