RESUMO
Cellular senescence causes a dramatic alteration of chromatin organization and changes the gene expression profile of proinflammatory factors, thereby contributing to various age-related pathologies through the senescence-associated secretory phenotype (SASP). Chromatin organization and global gene expression are maintained by the CCCTC-binding factor (CTCF); however, the molecular mechanism underlying CTCF regulation and its association with SASP gene expression remains unclear. We discovered that noncoding RNA (ncRNA) derived from normally silenced pericentromeric repetitive sequences directly impairs the DNA binding of CTCF. This CTCF disturbance increases the accessibility of chromatin and activates the transcription of SASP-like inflammatory genes, promoting malignant transformation. Notably, pericentromeric ncRNA was transferred into surrounding cells via small extracellular vesicles acting as a tumorigenic SASP factor. Because CTCF blocks the expression of pericentromeric ncRNA in young cells, the down-regulation of CTCF during cellular senescence triggers the up-regulation of this ncRNA and SASP-related inflammatory gene expression. In this study, we show that pericentromeric ncRNA provokes chromosomal alteration by inhibiting CTCF, leading to a SASP-like inflammatory response in a cell-autonomous and non-cell-autonomous manner and thus may contribute to the risk of tumorigenesis during aging.
Assuntos
Envelhecimento/genética , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Inflamação/genética , RNA não Traduzido/fisiologia , Fenótipo Secretor Associado à Senescência/genética , Animais , Senescência Celular/genética , Centrômero , DNA de Neoplasias/metabolismo , Feminino , Regulação da Expressão Gênica , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias , Ligação Proteica/genéticaRESUMO
Both the DNA damage response (DDR) and epigenetic mechanisms play key roles in the implementation of senescent phenotypes, but very little is known about how these two mechanisms are integrated to establish senescence-associated gene expression. Here we show that, in senescent cells, the DDR induces proteasomal degradation of G9a and GLP, major histone H3K9 mono- and dimethyltransferases, through Cdc14B- and p21(Waf1/Cip1)-dependent activation of APC/C(Cdh1) ubiquitin ligase, thereby causing a global decrease in H3K9 dimethylation, an epigenetic mark for euchromatic gene silencing. Interestingly, induction of IL-6 and IL-8, major players of the senescence-associated secretory phenotype (SASP), correlated with a decline of H3K9 dimethylation around the respective gene promoters and knockdown of Cdh1 abolished IL-6/IL-8 expression in senescent cells, suggesting that the APC/C(Cdh1)-G9a/GLP axis plays crucial roles in aspects of senescent phenotype. These findings establish a role for APC/C(Cdh1) and reveal how the DDR integrates with epigenetic processes to induce senescence-associated gene expression.
Assuntos
Senescência Celular , Dano ao DNA , Histona-Lisina N-Metiltransferase/metabolismo , Complexos Ubiquitina-Proteína Ligase/fisiologia , Ciclossomo-Complexo Promotor de Anáfase , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/fisiologia , DNA (Citosina-5-)-Metiltransferase 1 , DNA (Citosina-5-)-Metiltransferases/metabolismo , Fosfatases de Especificidade Dupla/genética , Fosfatases de Especificidade Dupla/metabolismo , Fosfatases de Especificidade Dupla/fisiologia , Antígenos de Histocompatibilidade/metabolismo , Histona Metiltransferases , Histonas/metabolismo , Humanos , Metilação , Transdução de SinaisRESUMO
We demonstrate the successful fabrication on CaF2 substrates of FeSe(1-x)Tex films with 0 ≤ x ≤ 1, including the region of 0.1 ≤ x ≤ 0.4, which is well known to be the "phase-separation region," via pulsed laser deposition that is a thermodynamically nonequilibrium method. In the resulting films, we observe a giant enhancement of the superconducting transition temperature, Tc, in the region of 0.1 ≤ x ≤ 0.4: The maximum value reaches 23 K, which is â¼ 1.5 times as large as the values reported for bulk samples ofFeSe(1-x)Te(x). We present a complete phase diagram of FeSe(1-x)Te(x) films. Surprisingly, a sudden suppression of Tc is observed at 0:1 < x < 0.2, whereas Tc increases with decreasing x for 0.2 ≤ x < 1. Namely, there is a clear difference between superconductivity realized in x = 0-0.1 and in x ≥ 0.2. To obtain a film of FeSe(1-x)Te(x) with high Tc, the controls of the Te content x and the in-plane lattice strain are found to be key factors.
RESUMO
A 37-year-old woman, who had undergone surgery of atrial septal defect (ASD) at 12-year-old, developed bradycardia and referred to our hospital. Transthoracic echocardiography revealed high echoic tumor in the right atrium. The image of the tumor was of low intensity by T2 weighted magnetic resonance imaging (MRI) and floating mass with a stalk to the right atrium in cine MRI. She underwent tumor resection under cardiopulmonary bypass. Histopathologilal examination of the tumor was calcified amorphous tumor. The postoperative course was uneventful.
Assuntos
Calcinose/cirurgia , Átrios do Coração/cirurgia , Neoplasias Cardíacas/cirurgia , Adulto , Calcinose/etiologia , Feminino , Átrios do Coração/patologia , Neoplasias Cardíacas/complicações , Neoplasias Cardíacas/patologia , Humanos , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios XRESUMO
Aim: The albumin-indocyanine green evaluation (ALICE) score is a useful predictor of post-hepatectomy liver failure (PHLF); however, its usefulness in combination with future liver remnant (FLR), measured by 3-D volumetry, has not been investigated. This study aimed to investigate the relationship between the ALICE of the FLR (ALICE-FLR) score and severe PHLF. Methods: The clinical data of 215 patients who underwent anatomical hepatectomy for hepatocellular carcinoma without portal vein embolization at two institutes between January 2010 and December 2021 were analyzed retrospectively. PHLF occurrence and severity were determined according to the International Study Group of Liver Surgery's definition. Grades B and C PHLF were defined as severe PHLF. The ALICE-FLR, ALICE scores, and indocyanine green clearance of FLR (ICGK-FLR) were evaluated for severe PHLF prediction. Results: Severe PHLF was observed in 40 patients (18.6%). The areas under the curve (AUCs) for the ALICE-FLR, ALICE scores, ICGK-FLR, and FLR were 0.76, 0.64, 0.73, and 0.69, respectively. The AUC of the ALICE-FLR score was significantly higher than that of the ALICE score. The ALICE-FLR score was identified as an independent predictor of severe PHLF (the odds ratio for every 0.01 increment in the ALICE-FLR score was 1.24; 95% confidence interval, 1.070-1.453; p = 0.004). Among patients with severe PHLF, the ALICE-FLR score was significantly higher in the grade C than in the grade B PHLF group. Conclusion: The combination of liver function models, including indocyanine green, albumin, and FLR is considered compatible for predicting severe PHLF.
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One of the most significant issues for superconductivity is clarifying the momentum-dependent superconducting gap Δ([Formula: see text]), which is closely related to the pairing mechanism. To elucidate the gap structure, it is essential to investigate Δ([Formula: see text]) in as many different physical quantities as possible and to crosscheck the results obtained in different methods with each other. In this paper, we report a combinatorial investigation of the superfluid density and the flux-flow resistivity of iron-pnictide superconductors; LiFeAs and BaFe2(As1-xPx)2 (x = 0.3, 0.45). We evaluated Δ([Formula: see text]) by fitting these two-independent quantities with a two-band model simultaneously. The obtained Δ([Formula: see text]) are consistent with the results observed in angle-resolved photoemission spectroscopy (ARPES) and scanning-tunneling spectroscopy (STS) studies. We believe our approach is a powerful method for investigating Δ([Formula: see text]) because it does not require a sample with clean surface unlike ARPES and STS experiments, or a rotational magnetic-field system for direct measurements of the angular dependence of thermodynamic quantities.
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Although cellular senescence acts primarily as a tumour suppression mechanism, the accumulation of senescent cells in vivo eventually exerts deleterious side effects through inflammatory/tumour-promoting factor secretion. Thus, the development of new drugs that cause the specific elimination of senescent cells, termed senolysis, is anticipated. Here, by an unbiased high-throughput screening of chemical compounds and a bio-functional analysis, we identify BET family protein degrader (BETd) as a promising senolytic drug. BETd provokes senolysis through two independent but integrated pathways; the attenuation of non-homologous end joining (NHEJ), and the up-regulation of autophagic gene expression. BETd treatment eliminates senescent hepatic stellate cells in obese mouse livers, accompanied by the reduction of liver cancer development. Furthermore, the elimination of chemotherapy-induced senescent cells by BETd increases the efficacy of chemotherapy against xenograft tumours in immunocompromised mice. These results reveal the vulnerability of senescent cells and open up possibilities for its control.
Assuntos
Antineoplásicos/administração & dosagem , Autofagia/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , Neoplasias/fisiopatologia , Animais , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
BACKGROUND: Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life. METHODS: This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time. RESULTS: A total of 58 patients in the single-incision group and 53 in the 4-port group (nâ¯=â¯111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval -0.4 to 3.2, Pâ¯=â¯.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy. CONCLUSION: Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.
Assuntos
Colecistectomia Laparoscópica/métodos , Qualidade de Vida , Fatores Etários , Emprego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória , Recuperação de Função Fisiológica , Retorno ao Trabalho , Fatores SexuaisRESUMO
Although neurons and glia inevitably undergo degeneration in the core of ischemic lesions, many cells, particularly immune cells, infiltrate the core and survive in it. Such infiltrating cells may play certain roles in the regeneration and repair of damaged brain tissues. In this study, we characterized macrophage-like cells that accumulated in the ischemic core of a rat brain whose right middle cerebral artery was transiently occluded for 90 mins. Many of the accumulated macrophage-like cells expressed Iba1, a marker of macrophages/microglia, as well as NG2 chondroitin sulfate proteoglycan (NG2), which has been recognized as a marker of oligodendrocyte progenitor cells. Such macrophage-like cells were termed BINCs (brain Iba1(+)/NG2(+) cells) to distinguish them from NG2(-)/Iba1(+) or NG2(+)/Iba1(-) cells that were also present in the perilesion and the contralateral hemisphere. Electron microscopy showed the localization of NG2 along the plasma membrane of cells that had many phagosomes and irregular-shaped or reniform heterochromatin-rich nuclei, which are characteristics of monocytes/macrophages. Brain Iba1(+)/NG2(+) cells were highly proliferative and their number peaked at 7 days post-reperfusion. An immunoblot analysis of NG2 revealed the presence of two NG2s: one expressed by BINCs with a molecular weight of 300 kDa, and the other found in the contralateral hemisphere with a molecular weight of 290 kDa. Taken the various functions of NG2, BINCs may be involved in not only phagocytosis of degenerated cells but also the healing and regeneration of lesion cores.
Assuntos
Antígenos/biossíntese , Proteínas de Ligação ao Cálcio/biossíntese , Regulação da Expressão Gênica , Infarto da Artéria Cerebral Média/metabolismo , Macrófagos/metabolismo , Proteoglicanas/biossíntese , Regeneração , Animais , Antígenos de Diferenciação/biossíntese , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Heterocromatina/metabolismo , Heterocromatina/ultraestrutura , Infarto da Artéria Cerebral Média/patologia , Macrófagos/ultraestrutura , Masculino , Proteínas dos Microfilamentos , Microglia/metabolismo , Microglia/ultraestrutura , Monócitos/metabolismo , Monócitos/ultraestrutura , Oligodendroglia/metabolismo , Oligodendroglia/ultraestrutura , Fagossomos/metabolismo , Fagossomos/ultraestrutura , Ratos , Ratos Wistar , Células-Tronco/metabolismo , Células-Tronco/ultraestrutura , Fatores de TempoRESUMO
Superconducting FeSe0.8Te0.2 thin films on SrTiO3, LaAlO3 and CaF2 substrates were electrochemically etched in an ionic liquid, DEME-TFSI, electrolyte with a gate bias of 5 V. Superconductivity at 38 K was observed on all substrates after the etching of films with a thickness greater than 30 nm, despite the different Tc values of 8 K, 12 K and 19 K observed before etching on SrTiO3, LaAlO3 and CaF2 substrates, respectively. Tc returned to its original value with the removal of the gate bias. The observation of Tc enhancement for these thick films indicates that the Tc enhancement is unrelated to any interfacial effects between the film and the substrate. The sheet resistance and Hall coefficient of the surface conducting layer were estimated from the gate bias dependence of the transport properties. The sheet resistances of the surface conducting layers of the films on LaAlO3 and CaF2 showed identical temperature dependence, and the Hall coefficient was found to be almost independent of temperature and to take values of -0.05 to -0.2 m2/C, corresponding to 4-17 electrons per FeSe0.8Te0.2 unit cell area in two dimensions. These common transport properties on various substrates suggest that the superconductivity at 38 K appears in the surface conducting layer as a result of an electrochemical reaction between the surface of the FeSe0.8Te0.2 thin film and the ionic liquid electrolyte.
RESUMO
The ionized calcium-binding adaptor molecule 1 (Iba1) with 147 amino acid residues has been identified as a calcium-binding protein, expressed specifically in microglia/macrophages, and is expected to be a key factor in membrane ruffling, which is a typical feature of activated microglia. We have determined the crystal structure of human Iba1 in a Ca(2+)-free form and mouse Iba1 in a Ca(2+)-bound form, to a resolution of 1.9 A and 2.1 A, respectively. X-ray structures of Iba1 revealed a compact, single-domain protein with two EF-hand motifs, showing similarity in overall topology to partial structures of the classical EF-hand proteins troponin C and calmodulin. In mouse Iba1, the second EF-hand contains a bound Ca(2+), but the first EF-hand does not, which is often the case in S100 proteins, suggesting that Iba1 has S100 protein-like EF-hands. The molecular conformational change induced by Ca(2+)-binding of Iba1 is different from that found in the classical EF-hand proteins and/or S100 proteins, which demonstrates that Iba1 has an unique molecular switching mechanism dependent on Ca(2+)-binding, to interact with target molecules.
Assuntos
Proteínas de Ligação ao Cálcio/química , Cálcio/química , Proteínas de Ligação a DNA/química , Modelos Moleculares , Sequência de Aminoácidos , Animais , Sítios de Ligação , Calmodulina/química , Cristalografia por Raios X , Humanos , Macrófagos/metabolismo , Camundongos , Proteínas dos Microfilamentos , Microglia/metabolismo , Dados de Sequência Molecular , Conformação Proteica , Proteínas S100/química , Troponina C/químicaRESUMO
The loss of epithelial polarity and tissue architecture is a diagnostic feature of malignant tumors. In Drosophila, genetic studies identified 3 neoplastic tumor suppressor genes (nTSGs), and a loss of nTSGs has been shown to result in a disruption of apical-basal polarity and neoplastic growth in epithelial cells. Scribble is one type of the Drosophila nTSGs, which encodes a membrane-associated cytoplasmic protein containing the multi-PDZ domain. In contrast to Drosophila scribble, the oncogenic roles of its mammalian homologues have not yet been established. We herein immunohistochemically examined the distributions of hScrib protein in human colorectal neoplasia using affinity-purified antibody. In 50 cases of colorectal adenomas and adenocarcinomas, the accumulation of hScrib protein was commonly observed in comparison with the adjacent normal epithelia. Furthermore, the overexpression and distribution of hScrib was observed to extensively overlap with the cytoplasmic accumulation of beta-catenin. Like beta-catenin, the intense immunoreactivity of hScrib was often observed in small adenomas, thus, suggesting that hScrib could be involved in an early step of colon carcinogenesis. Five corresponding liver metastases showed a comparable immunoreactivity for anti-hScrib in comparison with their primary sites. In an immunofluorescence analysis on cultured cell lines, the loss of membranous staining of hScrib was observed according to the cytoplasmic translocation of beta-catenin. We herein demonstrate that the accumulation of hScrib protein might therefore be involved in colon carcinogenesis while also providing a possible link between hScrib and beta-catenin.
Assuntos
Adenocarcinoma/patologia , Adenoma/patologia , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/patologia , Proteínas de Membrana/metabolismo , Proteínas Supressoras de Tumor/metabolismo , beta Catenina/metabolismo , Adenocarcinoma/metabolismo , Adenoma/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Linhagem Celular Tumoral , Neoplasias Colorretais/metabolismo , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-IdadeRESUMO
Heparanase is an enzyme that cleaves heparan sulfate proteoglycans, an important component of the extracellular matrix to generate heparan sulfate fragments, leading to the remodeling of the extracellular matrix and the basement membrane particularly during cancer metastasis. A growing body of evidence suggests that heparanase serves multiple functions in normal tissues including the central nervous system. In this study, we showed that heparanase is expressed in reactive astrocytes in the peri-infarct lesion of a rat brain whose middle cerebral artery was transiently occluded for 90 min. RT-PCR and Western blot analyses revealed that heparanase expression was markedly upregulated during the subacute phase of ischemia (from 3 to 7 days post-reperfusion (dpr)). As revealed by immunohistochemical study, heparanase was localized in astrocytes located in the peri-infarct region. Heparanase+ astrocytes expressed nestin that is known as a marker of reactive astrocytes. Infiltrated neutrophils were weakly heparanase+. After 7 dpr, the expression level of heparanase+ astrocytes considerably decreased. Therefore, the maximum expression of heparanase by astrocytes may correlate with the time of migration of reactive astrocytes toward the ischemic core, which may result in astrogliosis. These findings suggest a novel role of heparanase in the pathophysiology of brain ischemia.
Assuntos
Astrócitos/metabolismo , Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Gliose/metabolismo , Glucuronidase/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Biomarcadores/análise , Biomarcadores/metabolismo , Encéfalo/fisiopatologia , Infarto Encefálico/metabolismo , Infarto Encefálico/fisiopatologia , Isquemia Encefálica/fisiopatologia , Movimento Celular/fisiologia , Quimiotaxia de Leucócito/fisiologia , Gliose/fisiopatologia , Glucuronidase/genética , Imuno-Histoquímica , Infarto da Artéria Cerebral Média/metabolismo , Infarto da Artéria Cerebral Média/fisiopatologia , Masculino , Nestina , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/fisiopatologia , Fatores de Tempo , Regulação para Cima/fisiologiaRESUMO
Brain ischemia causes the death of neurons and glial cells. Such brain cells are believed to inevitably undergo degeneration in the core of ischemic lesions, whereas neurons and glial cells may survive in the region surrounding the core that is often referred to as the ischemic penumbra. However, many cells, particularly immune cells infiltrate and survive in the core. In this study, we characterized macrophage-like cells that accumulated in the ischemic core of a rat brain whose right middle cerebral artery was transiently occluded for 90 min. At 7 days post-reperfusion, we observed macrophage-like cells expressing CD200, a cell surface glycoprotein belonging to an immunoglobulin superfamily and that elicits suppressive effects on myeloid cells including microglia by interacting with the CD200 receptor (CD200R). RT-PCR and immunoblot analyses revealed the presence of CD200-mRNA and protein in the ischemic core as well as in the contralateral region. As revealed by immunohistochemistry, CD200 is located on the cell membrane of spherical Iba1(+) cells with many cytoplasmic granules. CD200(-)/Iba1(+) macrophage-like cells were also present, which have a more irregular shape than CD200(+)/Iba1(+) cells. CD200 was detected in isolated spherical Iba1(+) macrophage-like cells. Thus, CD200 is expressed in some populations of macrophage-like cells that may be responsible for the suppression of CD200R(+) myeloid cell functions in the ischemic core.
Assuntos
Antígenos CD/metabolismo , Encéfalo/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Infarto da Artéria Cerebral Média/patologia , Macrófagos/metabolismo , Animais , Encéfalo/patologia , Expressão Gênica , Hipóxia-Isquemia Encefálica/etiologia , Hipóxia-Isquemia Encefálica/metabolismo , Hipóxia-Isquemia Encefálica/patologia , Immunoblotting , Imuno-Histoquímica , Infarto da Artéria Cerebral Média/complicações , Masculino , Microglia/metabolismo , RNA Mensageiro/análise , Ratos , Ratos Wistar , Receptores Imunológicos/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Differences in sugar distribution between the villous epithelium and follicle-associated epithelium (FAE) were compared using lectins in the rabbit small intestine. In every portion, villous columnar epithelial cells primarily exhibited a positive reaction to the GalNAc, GlcNAc, galactose, and oligosaccharide. In the ileal Peyer's patch (PP), whereas microvillous epithelial cells exhibited positive reactions, M cells tended to be negative. The villous epithelial reaction to the fucose group was negative, but M cells and microvillous epithelial cells showed a positive to the fucose. No epithelium had a positive reaction to the mannose and glucose. The variety of lectin-binding properties of villous epithelial cells and M cells may reflect specificity for the recognizing luminal substances such as antigenic molecules and bacterial elements.
Assuntos
Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Lectinas/metabolismo , Animais , Biomarcadores , Carboidratos , Mucosa Intestinal/citologia , Intestino Delgado/anatomia & histologia , Masculino , Ligação Proteica , CoelhosRESUMO
Iron chalcogenide superconductors FeSe1-xTex are important materials for investigating the relation be-tween the superconductivity and the orbital and/or electronic nematic order, because the end member material FeSe exhibits a structural transition without a magnetic phase transition. However, the phase separation occurs in the region of 0.1 ≤ x ≤ 0.4 for bulk samples, and it prevents the complete understanding of this system. Here, we report the successful fabrication of epitaxial thin films of FeSe1-xTex with 0 ≤ x ≤ 0.7, which includes the phase-separation region, on LaAlO3 substrates via pulsed laser deposition. In the temperature dependences of differential resistivity for these films with 0 ≤ x ≤ 0.3, the dip- or peak- anomalies, which are well-known to be originated from the structural transition in FeSebulk samples, are observed at the characteristic temperatures, T*. The doping-temperature (x-T) phase diagram of FeSe1-xTex films clearly shows that T* decreases with increasing x, and that Tc suddenly changes at a certain Te content where T* disappears, which turns out to be commonly observed for both films on LaAlO3 and CaF2. These indicate the importance of controlling the structural transition to achieve high Tc in iron chalcogenides.
RESUMO
We present a design for a tunneling-current-assisted scanning near-field microwave microscope. For stable operation at cryogenic temperatures, making a small and rigid microwave probe is important. Our coaxial resonator probe has a length of approximately 30 mm and can fit inside the 2-in. bore of a superconducting magnet. The probe design includes an insulating joint, which separates DC and microwave signals without degrading the quality factor. By applying the SMM to the imaging of an electrically inhomogeneous superconductor, we obtain the spatial distribution of the microwave response with a spatial resolution of approximately 200 nm. Furthermore, we present an analysis of our SMM probe based on a simple lumped-element circuit model along with the near-field microwave measurements of silicon wafers having different conductivities.
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There is growing evidence that chemokines play important roles in the immune surveillance of central nervous system (CNS). In the CNS, microglia are primary immune effector cells and secrete various chemokines in response to their microenvironment. Using the RT-PCR procedure and indirect immunofluorescence analysis, we found that CCL6 (known as C10/MRP-1 in mouse) was expressed in rat primary microglia without any stimulation, but not in primary astrocytes, although both cell types expressed CCR1 mRNA, which is a receptor for CCL6. Furthermore, immunohistochemical analysis demonstrated that microglia produced CCL6 protein in a normal brain, suggesting that microglia may be the primary source of CCL6 in a normal brain. Recombinant rat CCL6 mediated the migration of microglia and astrocytes in vitro. The CCL6-mediated cell migration was blocked by treating the cells with LY294002, a PI3-kinase inhibitor and Western blot analysis showed that the phosphorylation of Akt could be induced by treating microglia with a recombinant CCL6, suggesting that CCL6 functions by activating the PI3-kinase/Akt pathway. A proinflammatory cytokine, interferon-gamma enhanced the expression of both CCL6 mRNA and protein in microglia, while other proinflammatory cytokines, interleukin-6 and tumor necrosis factor-alpha and an anti-inflammatory cytokine, transforming growth factor-beta exerted no effect on CCL6 expression in microglia. These findings suggest that CCL6 may be a mediator released by microglia for cell-cell communication under physiological as well as pathological conditions of CNS.
Assuntos
Comunicação Celular/fisiologia , Quimiocinas CC/fisiologia , Expressão Gênica/fisiologia , Microglia/metabolismo , Análise de Variância , Animais , Animais Recém-Nascidos , Northern Blotting/métodos , Western Blotting/métodos , Contagem de Células/métodos , Células Cultivadas , Quimiocinas CC/genética , Quimiocinas CC/farmacologia , Quimiotaxia/efeitos dos fármacos , Quimiotaxia/fisiologia , Cromonas/farmacologia , Clonagem Molecular/métodos , Citocinas/farmacologia , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Imunofluorescência/métodos , Expressão Gênica/efeitos dos fármacos , Interferon gama/metabolismo , Interleucina-6/metabolismo , Lectinas/metabolismo , Camundongos , Microglia/efeitos dos fármacos , Morfolinas/farmacologia , Prosencéfalo/citologia , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Tempo , Distribuição Tecidual , Fator de Crescimento Transformador beta/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Using beta-amyloid precursor protein immunolabeling, we have detected axonal injury in experimental herpes simplex encephalitis. beta-amyloid precursor protein-specific signals were found in the mouse brain as either puncta or axon-like structures. They appeared where infected neurons were undergoing apoptosis and Iba1-immunopositive microglia transformed themselves into macrophages. These results show, for the first time, that axonal injury, i.e., functional disturbance of the fast axonal transport, can take place during the course of acute viral encephalitis.
Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Axônios/patologia , Encefalite por Herpes Simples/fisiopatologia , Animais , Apoptose/fisiologia , Axônios/metabolismo , Axônios/virologia , Proteínas de Ligação ao Cálcio/metabolismo , Encefalite por Herpes Simples/patologia , Imuno-Histoquímica/métodos , Camundongos , Camundongos Endogâmicos BALB C , Proteínas dos Microfilamentos , Microglia/metabolismo , Microglia/patologia , Microglia/virologiaRESUMO
The p16(INK4a) tumour suppressor has an established role in the implementation of cellular senescence in stem/progenitor cells, which is thought to contribute to organismal ageing. However, since p16(INK4a) knockout mice die prematurely from cancer, whether p16(INK4a) reduces longevity remains unclear. Here we show that, in mutant mice homozygous for a hypomorphic allele of the α-klotho ageing-suppressor gene (kl(kl/kl)), accelerated ageing phenotypes are rescued by p16(INK4a) ablation. Surprisingly, this is due to the restoration of α-klotho expression in kl(kl/kl) mice and does not occur when p16(INK4a) is ablated in α-klotho knockout mice (kl(-/-)), suggesting that p16(INK4a) is an upstream regulator of α-klotho expression. Indeed, p16(INK4a) represses α-klotho promoter activity by blocking the functions of E2Fs. These results, together with the observation that the expression levels of p16(INK4a) are inversely correlated with those of α-klotho throughout ageing, indicate that p16(INK4a) plays a previously unrecognized role in downregulating α-klotho expression during ageing.