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Recent studies have shown a role of inflammation in muscle atrophy and sarcopenia. However, no anti-inflammatory pharmacotherapy has been established for the treatment of sarcopenia. Here, we investigate the potential role of PPARα and its ligands on inflammatory response and PGC-1α gene expression in LPS-treated C2C12 myotubes. Knockdown of PPARα, whose expression was upregulated upon differentiation, augmented IL-6 or TNFα gene expression. Conversely, PPARα overexpression or its activation by ligands suppressed 2-h LPS-induced cytokine expression, with pemafibrate attenuating NF-κB or STAT3 phosphorylation. Of note, reduction of PGC-1α gene expression by LPS treatment for 24 hours was partially reversed by fenofibrate. Our data demonstrate a critical inhibitory role of PPARα in inflammatory response of C2C12 myotubes and suggest a future possibility of PPARα ligands as a candidate for anti-inflammatory therapy against sarcopenia.
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PPAR alfa , Sarcopenia , Anti-Inflamatórios/metabolismo , Lipopolissacarídeos/metabolismo , Fibras Musculares Esqueléticas/metabolismo , NF-kappa B/metabolismo , PPAR alfa/metabolismo , Sarcopenia/metabolismo , Animais , CamundongosRESUMO
Experimental observations indicate that pressure treatments transform the monoclinic and orthorhombic low-temperature phases of Mg2NiH4 into an unresolved pseudocubic phase even at room temperatures, resembling the temperature-induced phase transformation of the material. This pressure-induced phase transformation is anticipated to involve deformations of the tetrahedrally bonded NiH4 molecular ion and the metal lattice. However, the precise mechanism underlying this transformation remains unclear. To elucidate this behavior, this study adopted first-principles density functional theory calculations to investigate the effect of applied pressure on the observed phase transition. The results revealed that the phase transition from the low-temperature phases to the pseudocubic phase occurs at approximately 8-9 GPa. Furthermore, at this pressure, the metal lattice deforms into an antifluorite-like structure, and the NiH4 molecular ion undergoes substantial distortion, resulting in the alignment of hydrogen atoms along the crystal axes of the metal lattice. Furthermore, through a comprehensive structural exploration, we successfully identified several tetragonal and orthorhombic models that are energetically more stable than the low-temperature phases at low pressures. These models are potential candidates for elucidating the pseudocubic phase observed in experiments. Overall, our findings are anticipated to enhance the current understanding of the structural changes occurring during pressure and temperature-induced phase transitions.
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Transition metal dichalcogenide (TMDC) nanotubes exhibit unique physical properties due to their nanotube structures. The development of techniques for synthesizing TMDC nanotubes with controlled structures is very important for their science and applications. However, structural control efforts have been made only for the homostructures of TMDC nanotubes and not for their heterostructures that provide an important platform for their two-dimensional counterparts. In this study, we synthesized heterostructures of TMDC nanotubes, MoS2/WS2 heteronanotubes, and demonstrated a technique for controlling features of their structures, such as diameters, layer numbers, and crystallinity. The diameter of the heteronanotubes could be tuned with inner nanotube templates and was reduced by using small-diameter WS2 nanotubes. The layer number and crystallinity of the MoS2 outer wall could be controlled by controlling their precursors and synthesis temperatures, resulting in the formation of high-crystallinity TMDC heteronanotubes with specific chirality. This study can expand the research of van der Waals heterostructures.
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Endocrine-disrupting chemicals (EDCs) often affect homeostatic regulation in living organisms by directly acting on nuclear receptors (NRs). Retinoid X receptors (RXRs), the most highly conserved members of the NR superfamily during evolution, function as partners to form heterodimers with other NRs, such as retinoic acid, thyroid hormone, and vitamin D3 receptors. RXRs also homodimerize and induce the expression of target genes upon binding with their natural ligand, 9-cis-retinoic acid (9cRA), and typical EDCs organotin compounds, such as tributyltin and triphenyltin. In the present study, we established a new yeast reporter gene assay (RGA) to detect the ligands of freshwater cladoceran Daphnia magna ultraspiracle (Dapma-USP), a homolog of vertebrate RXRs. D. magna has been used as a representative crustacean species for aquatic EDC assessments in the Organization for Economic Corporation and Development test guidelines. Dapma-USP was expressed along with the Drosophila melanogaster steroid receptor coactivator Taiman in yeast cells carrying the lacZ reporter plasmid. The RGA for detecting agonist activity of organotins and o-butylphenol was improved by use of mutant yeast strains lacking genes encoding cell wall mannoproteins and/or plasma membrane drug efflux pumps as hosts. We also showed that a number of other human RXR ligands, phenol and bisphenol A derivatives, and terpenoid compounds such as 9c-RA exhibited antagonist activity on Dapma-USP. Our newly established yeast-based RGA system is valuable as the first screening tool to detect ligand substances for Dapma-USP and for evaluating the evolutionary divergence of the ligand responses of RXR homologs between humans and D. magna.
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Daphnia , Saccharomyces cerevisiae , Animais , Humanos , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Ligantes , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Genes Reporter , Daphnia/genética , Daphnia/metabolismo , Drosophila melanogaster/genética , Vertebrados/genética , Vertebrados/metabolismoRESUMO
Smoking cessation increases body weight. The underlying mechanisms, however, have not been fully understood. We here report an establishment of a mouse model that exhibits an augmented body weight gain after nicotine withdrawal. High fat diet-fed mice were infused with nicotine for two weeks, and then with vehicle for another two weeks using osmotic minipumps. Body weight increased immediately after nicotine cessation and was significantly higher than that of mice continued on nicotine. Mice switched to vehicle consumed more food than nicotine-continued mice during the first week of cessation, while oxygen consumption was comparable. Elevated expression of orexigenic agouti-related peptide was observed in the hypothalamic appetite center. Pair-feeding experiment revealed that the accelerated weight gain after nicotine withdrawal is explained by enhanced energy intake. As a showcase of an efficacy of pharmacologic intervention, exendin-4 was administered and showed a potent suppression of energy intake and weight gain in mice withdrawn from nicotine. Our current model provides a unique platform for the investigation of the changes of energy regulation after smoking cessation.
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Nicotina/efeitos adversos , Síndrome de Abstinência a Substâncias/patologia , Aumento de Peso , Proteína Relacionada com Agouti/metabolismo , Animais , Calorimetria , Respiração Celular/efeitos dos fármacos , Modelos Animais de Doenças , Ingestão de Energia/efeitos dos fármacos , Exenatida/farmacologia , Comportamento Alimentar/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Camundongos Endogâmicos C57BL , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Síndrome de Abstinência a Substâncias/genética , Aumento de Peso/efeitos dos fármacos , Aumento de Peso/genéticaRESUMO
Ecdysone agonists are a class of insecticides that activate the ecdysone receptor (EcR) heterodimerized with the ultraspiracle (USP). Here, we report a new luciferase reporter assay for ecdysone agonists. The assay employs mammalian HEK293T cells transiently transfected with the EcR and USP genes of Chilo suppressalis, along with the taiman (Tai) gene of Drosophila melanogaster that encodes a steroid receptor coactivator. This assay system gave results consistent with those of radioligand binding assays and showed sensitivity superior to that of the existing in vitro methods. In addition, use of the heterologous host cells precludes perturbation from intrinsic players of the ecdysone signaling, which is a potential drawback of insect cell-based methods. This reporter system is suitable for detailed structure-activity analysis of ecdysone agonists and will serve as a valuable tool for the rational design of novel insect growth regulators.
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Proteínas de Drosophila , Inseticidas , Receptores de Esteroides , Animais , Humanos , Ecdisona/farmacologia , Ecdisona/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Células HEK293 , Receptores de Esteroides/genética , Receptores de Esteroides/metabolismo , Luciferases/genética , Hormônios Juvenis , Mamíferos/metabolismoRESUMO
Transverse thermoelectric generation using magnetic materials is essential to develop active thermal engineering technologies, for which the improvements of not only the thermoelectric output but also applicability and versatility are required. In this study, using combinatorial material science and lock-in thermography technique, we have systematically investigated the transverse thermoelectric performance of Sm-Co-based alloy films. The high-throughput material investigation revealed the best Sm-Co-based alloys with the large anomalous Nernst effect (ANE) as well as the anomalous Ettingshausen effect (AEE). In addition to ANE/AEE, we discovered unique and superior material properties in these alloys: the amorphous structure, low thermal conductivity, and large in-plane coercivity and remanent magnetization. These properties make it advantageous over conventional materials to realize heat flux sensing applications based on ANE, as our Sm-Co-based films can generate thermoelectric output without an external magnetic field. Importantly, the amorphous nature enables the fabrication of these films on various substrates including flexible sheets, making the large-scale and low-cost manufacturing easier. Our demonstration will provide a pathway to develop flexible transverse thermoelectric devices for smart thermal management.
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Pemafibrate, a selective peroxisome proliferator-activated receptor (PPAR) α modulator, is a new drug that specifically modulates PPARα conformation and co-activator recruitment, thereby lowers plasma triglycerides with less off-target effects. Classical PPARα ligands such as fenofibrate suppress inflammatory cells including microglia. However, effects of pemafibrate on microglia have never been addressed. Here we show that pemafibrate, like other PPARα ligands, potently suppressed NF-κB phosphorylation and cytokine expression in microglial cells. PPARα knockdown significantly amplified LPS-induced cytokine expression. Pemafibrate-induced suppression of IL-6 expression was reversed by PPARα knockdown. However, suppression by fenofibrate was not reversed by PPARα knockdown but by Sirtuin 1 (SIRT1) knockdown. In conclusion, pemafibrate and fenofibrate similarly suppresses microglial activation but through distinct PPARα and SIRT1-dependet pathways.
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Anti-Inflamatórios/farmacologia , Benzoxazóis/farmacologia , Butiratos/farmacologia , Microglia/efeitos dos fármacos , PPAR alfa/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sirtuína 1/metabolismo , Animais , Linhagem Celular , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismoRESUMO
Growth hormone (GH) has multiple physiological roles, acting on many organs. In order to investigate its roles in rat liver, we tried to identify novel genes whose transcription was regulated by GH. We identified X-box binding protein 1 (Xbp1) as a candidate gene. XBP1 is a key transcription factor activated in response to endoplasmic reticulum (ER) stress. The purpose of this study was to investigate the mode of action of GH on XBP1, including the relation with ER stress, sex-dependent expression of the mRNA, and the signaling pathway. Intravenous administration of GH rapidly and transiently increased Xbp1 mRNA in hypophysectomized rat livers. Neither phosphorylated inositol-requiring-1α (IRE1α) nor phosphorylated PKR-like ER kinase (PERK) increased, suggesting that Xbp1 expression is induced by an ER stress-independent mechanism. The active form of XBP1(S) protein was increased by GH administration and was followed by an increased ER-associated dnaJ protein 4 (ERdj4) mRNA level. XBP1(S) protein levels were predominantly identified in male rat livers with variations among individuals similar to those of phosphorylated signal transducer and activator of transcription 5B (STAT5B), suggesting that XBP1(S) protein levels are regulated by the sex-dependent secretary pattern of GH. The GH signaling pathway to induce Xbp1 mRNA was examined in rat hepatoma H4IIE cells. GH induced the phosphorylation of CCAAT/enhancer-binding protein ß (C/EBPß) following extracellular signal-regulated protein kinase (ERK) phosphorylation. Taken together, the results indicated that XBP1 is activated by GH in rat liver in a sexually dimorphic manner via ERK and C/EBPß pathway.
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Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Hormônio do Crescimento/farmacologia , Fígado/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases , RNA Mensageiro/efeitos dos fármacos , Proteína 1 de Ligação a X-Box/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático/genética , Endorribonucleases/efeitos dos fármacos , Endorribonucleases/metabolismo , Proteínas de Choque Térmico HSP40/efeitos dos fármacos , Proteínas de Choque Térmico HSP40/genética , Hipofisectomia , Fígado/metabolismo , Complexos Multienzimáticos/efeitos dos fármacos , Complexos Multienzimáticos/metabolismo , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , RNA Mensageiro/metabolismo , Ratos , Fator de Transcrição STAT5/efeitos dos fármacos , Fator de Transcrição STAT5/metabolismo , Caracteres Sexuais , Transdução de Sinais , Proteína 1 de Ligação a X-Box/genética , eIF-2 Quinase/efeitos dos fármacos , eIF-2 Quinase/metabolismoRESUMO
Previous studies including ours have shown that a low-protein diet up-regulates insulin signaling in the liver and muscle and induces fatty liver in rats. Adiponectin is known as an insulin-sensitizing adipocytokine. We, therefore, examined the effect of a low-protein diet on the adiponectin levels in rats. The low-protein diet significantly increased serum adiponectin level. However, mRNA and protein levels of adiponectin in white adipose tissue (WAT) were not changed by the low-protein diet. Since it is known that oligomerization is important to control serum adiponectin level, we examined the population of adiponectin oligomeric forms in WAT and found that low-protein diet did not change it. Despite these events, the amount of its secretion was significantly increased in the adipocytes isolated from WAT of low-protein diet-fed rats. These results indicate that a low-protein diet enhances adiponectin secretion, which is not due to the increased intracellular amount and oligomerization of adiponectin.
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Adiponectina/metabolismo , Proteínas Alimentares/administração & dosagem , Adiponectina/genética , Tecido Adiposo Branco/citologia , Tecido Adiposo Branco/metabolismo , Animais , Biopolímeros/metabolismo , Resistência à Insulina , Masculino , RNA Mensageiro/genética , Ratos , Ratos WistarRESUMO
AIM: To assess the efficacy and safety of telaprevir (TVR) when used in combination with natural human interferon-ß (IFN-ß) and ribavirin (RBV) for genotype 1 patients with depression compared to IFN-ß/RBV therapy in Japan. We also examined the efficacy of the TVR/IFN-ß/RBV therapy in treatment failure genotype 2 patients with depression. METHODS: For the genotype 1 patients, 30 patients received TVR (750 mg every 8 h) for 12 weeks combined with IFN-ß and RBV for 24 weeks (Group A), and 30 received IFN-ß and RBV for 48 weeks (Group B). For the genotype 2 patients, 14 patients were dosed only with the TVR-based regimen. RESULTS: The sustained virologic response (SVR) rates for Group A and Group B were 63.3% and 20.0%, respectively (P = 0.001, likelihood ratio test). The SVR rate for genotype 2 patients previously treated with pegylated IFN and/or RBV was 71.4%. No patient dropped out due to exacerbation of depression. The trend of platelet counts after the drugs were given was similar in the TVR/IFN-ß/RBV therapy group and the IFN-ß/RBV therapy group. Common resistance-associated variants of TVR were identified in 4 of the 13 patients who did not achieve SVR. CONCLUSION: This study showed that an addition of TVR to IFN-ß/RBV therapy raised SVR in previously treated and untreated genotype 1 patients and previously treated genotype 2 patients with chronic hepatitis C and depression.
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ß-Klotho (ß-Kl), a transmembrane protein expressed in the liver, pancreas, adipose tissues, and brain, is essential for feedback suppression of hepatic bile acid synthesis. Because bile acid is a key regulator of lipid and energy metabolism, we hypothesized potential and tissue-specific roles of ß-Kl in regulating plasma lipid levels and body weight. By crossing ß-kl(-/-) mice with newly developed hepatocyte-specific ß-kl transgenic (Tg) mice, we generated mice expressing ß-kl solely in hepatocytes (ß-kl(-/-)/Tg). Gene expression, metabolomic, and in vivo flux analyses consistently revealed that plasma level of cholesterol, which is over-excreted into feces as bile acids in ß-kl(-/-), is maintained in ß-kl(-/-) mice by enhanced de novo cholesterogenesis. No compensatory increase in lipogenesis was observed, despite markedly decreased plasma triglyceride. Along with enhanced bile acid synthesis, these lipid dysregulations in ß-kl(-/-) were completely reversed in ß-kl(-/-)/Tg mice. In contrast, reduced body weight and resistance to diet-induced obesity in ß-kl(-/-) mice were not reversed by hepatocyte-specific restoration of ß-Kl expression. We conclude that ß-Kl in hepatocytes is necessary and sufficient for lipid homeostasis, whereas nonhepatic ß-Kl regulates energy metabolism. We further demonstrate that in a condition with excessive cholesterol disposal, a robust compensatory mechanism maintains cholesterol levels but not triglyceride levels in mice.
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Peso Corporal/fisiologia , Hepatócitos/metabolismo , Metabolismo dos Lipídeos/fisiologia , Proteínas de Membrana/metabolismo , Animais , Colesterol/genética , Colesterol/metabolismo , Metabolismo Energético/fisiologia , Hepatócitos/citologia , Proteínas Klotho , Proteínas de Membrana/genética , Camundongos , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismoRESUMO
A 77-year-old woman with arteriovenous shunt for hemodialysis in the left forearm suffered from subarachnoid hemorrhage due to the rupture of a saccular aneurysm located on the left lateral wall of vertebrobasilar junction. Her left subclavian artery was severely stenosed and subclavian steal phenomenon was demonstrated on the digital subtraction angiography. Embolization of the parent artery including the aneurysm using detachable coils resulted in the successful obliteration of the aneurysm through the revascularized left subclavian artery. This is the first case in which the vertebrobasilar junction aneurysm would be caused by the hemodynamic stress due to the subclavian steal phenomenon combined with the shunt for hemodialysis in the left forearm.
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Aneurisma Roto/complicações , Aneurisma Intracraniano/complicações , Síndrome do Roubo Subclávio/etiologia , Artéria Vertebral , Idoso , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/fisiopatologia , Aneurisma Roto/terapia , Angiografia Digital , Angioplastia com Balão , Artéria Basilar/diagnóstico por imagem , Artéria Basilar/fisiopatologia , Angiografia Cerebral/métodos , Circulação Cerebrovascular , Angiografia por Tomografia Computadorizada , Embolização Terapêutica , Evolução Fatal , Feminino , Hemodinâmica , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/fisiopatologia , Aneurisma Intracraniano/terapia , Síndrome do Roubo Subclávio/diagnóstico por imagem , Síndrome do Roubo Subclávio/fisiopatologia , Síndrome do Roubo Subclávio/terapia , Resultado do Tratamento , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/fisiopatologiaRESUMO
BACKGROUND: Acute coronary syndrome (ACS) may occur during any human activity, including driving. The objectives of this study were to report the frequency of ACS occurring while driving, clarify patient characteristics, and analyze the behavioral patterns of drivers who sustained ACS. METHODS: A single-center, retrospective observational study was conducted using prospectively acquired data. Among 1605 ACS patients admitted between January 2011 and December 2016, 65 (60 men/5 women) patients who sustained ACS while driving were identified. Clinical variables were compared between these 65 patients and 1540 patients who sustained ACS while performing other activities. Furthermore, multivariable regression analysis was performed to identify variables associated with ACS. RESULTS: The frequency of ACS occurring while driving was 4.0% (65/1605). Compared with patients who sustained ACS while performing other activities, those who sustained ACS while driving were significantly younger (66.2 ± 13.0 vs. 57.5 ± 12.2 years, p < 0.001) and more likely to smoke (34.2 vs. 60.0%, p < 0.001). Multivariable regression analysis showed that age (OR 0.961; 95% CI 0.940-0.982) and current smoking (OR 1.978; 95% CI 1.145-3.417) were associated with ACS. While 55 drivers (85%) who remained conscious after ACS could seek medical attention without causing accidents, the other 10 (15%) who sustained cardiac arrest caused accidents. CONCLUSIONS: The association between current smoking and ACS occurring while driving suggests that smoking cessation is advised for smokers who drive from the standpoint of driving safety. We expect that prospective studies be conducted to verify our findings and identify individuals at risk for ACS while driving.
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Síndrome Coronariana Aguda/epidemiologia , Condução de Veículo , Síndrome Coronariana Aguda/etiologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Fatores de Risco , FumarRESUMO
Omeprazole (OME) induces the expression of genes encoding drug-metabolizing enzymes, such as CYP1A1, via activation of the aryl hydrocarbon receptor (AhR) both in vivo and in vitro. However, the precise mechanism of OME-mediated AhR activation is still under investigation. While elucidating species-specific susceptibility to dioxin, we found that OME-mediated AhR activation was mammalian species specific. Moreover, we previously reported that OME has inhibitory activity toward CYP1A1 enzymes. From these observations, we speculated that OME-mediated AhR target gene transcription is due to AhR activation by increasing amounts of putative AhR ligands in serum by inhibition of CYP1A1 activity. We compared the amino acid sequences of OME-sensitive rabbit AhR and nonsensitive mouse AhR to identify the residues responsible for the species-specific response. Chimeric AhRs were constructed by exchanging domains between mouse and rabbit AhRs to define the region required for the response to OME. OME-mediated transactivation was observed only with the chimeric AhR that included the ligand-binding domain (LBD) of the rabbit AhR. Site-directed mutagenesis revealed three amino acids (M328, T353, and F367) in the rabbit AhR that were responsible for OME-mediated transactivation. Replacing these residues with those of the mouse AhR abolished the response of the rabbit AhR. In contrast, substitutions of these amino acids with those of the rabbit AhR altered nonsensitive mouse AhR to become sensitive to OME. These results suggest that OME-mediated AhR activation requires a specific structure within LBD that is probably essential for binding with enigmatic endogenous ligands.
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Omeprazol/farmacologia , Inibidores da Bomba de Prótons/farmacologia , Receptores de Hidrocarboneto Arílico/química , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células Cultivadas , Citocromo P-450 CYP1A1/antagonistas & inibidores , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/fisiologia , Cobaias , Humanos , Ligantes , Camundongos , Dados de Sequência Molecular , Dibenzodioxinas Policloradas/farmacologia , Receptores de Hidrocarboneto Arílico/metabolismo , Especificidade da EspécieRESUMO
Omeprazole (OME), a proton pump inhibitor used to treat gastritis, is also an aryl hydrocarbon receptor (AhR) activator. OME activates AhR in human hepatocytes and hepatoma cells, but not in mice in vivo or in vitro. We recently discovered that this species-specific difference results from a difference in a few amino acids in the ligand-binding domain of AhR. However, OME activates both mouse and human AhRs in the yeast reporter assay system. Nevertheless, the cause of this discrepancy in OME responses remains unknown. Here, we report that CYP1A1 mRNA expression in mouse cecum was elevated after OME administration, although the mouse is regarded as an OME-unresponsive animal. Using the yeast reporter assay system with human and murine AhRs, we found AhR agonist-like activity in the cecal extracts of OME-treated mice. We speculated that OME metabolites produced by cecal bacteria might activate murine AhRs in vivo. In high-performance liquid chromatography (HPLC) analysis, AhR agonist-like activity of cecal bacterial culture and cecal extracts were detected at the same retention time. AhR agonist-like activity was also detected in the HPLC fractions of yeast culture media containing OME. This unknown substance could induce reporter gene expression via mouse and human AhRs. The agonist-like activity of the OME metabolite was reduced by concomitant α-naphthoflavone exposure. These results indicate that a yeast-generated OME metabolite elicited the response of mouse AhR to OME in the yeast system, and that bacterial OME metabolites may act as AhR ligands in human and mouse intestines.
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Fatores de Transcrição Hélice-Alça-Hélice Básicos/agonistas , Omeprazol/metabolismo , Omeprazol/farmacologia , Receptores de Hidrocarboneto Arílico/agonistas , Saccharomyces cerevisiae/metabolismo , Animais , Benzoflavonas/farmacologia , Biotransformação , Ceco/efeitos dos fármacos , Ceco/metabolismo , Ceco/microbiologia , Células Cultivadas , Meios de Cultura/metabolismo , Citocromo P-450 CYP1A1/biossíntese , Humanos , Camundongos , Omeprazol/antagonistas & inibidoresRESUMO
Pierisin is a DNA-targeting ADP-ribosyltransferase found in cabbage white butterfly (Pieris rapae). Pierisin transfers an ADP-ribosyl moiety to the 2-amino group of the guanine residue in DNA, yielding N2-(ADP-ribos-1-yl)-2'-deoxyguanosine (N2-ADPR-dG). Generally, such chemically modified DNA is recognized as DNA damage and elicits cellular responses, including DNA repair pathways. In Escherichia coli and human cells, it has been experimentally demonstrated that N2-ADPR-dG is a substrate of the nucleotide excision repair system. Although DNA repair machineries can remove most lesions, some unrepaired damages frequently lead to mutagenesis through DNA replication. Replication past the damaged DNA template is called translesion DNA synthesis (TLS). In vitro primer extension experiments have shown that eukaryotic DNA polymerase κ is involved in TLS across N2-ADPR-dG. In many cases, TLS is error-prone and thus a mutagenic process. Indeed, the induction of G:C to T:A and G:C to C:G mutations by N2-ADPR-dG in the hypoxanthine phosphoribosyltransferase gene mutation assay with Chinese hamster cells and supF shuttle vector plasmids assay using human fibroblasts has been reported. This review provides a detailed overview of DNA repair, TLS and mutagenesis of N2-ADPR-dG induced by cabbage butterfly pierisin-1.
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Reparo do DNA , DNA , Mutagênese , Animais , Humanos , DNA/genética , ADP Ribose Transferases/genética , ADP Ribose Transferases/metabolismo , Dano ao DNA , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Borboletas/genética , Borboletas/enzimologiaRESUMO
Investigating how the thermal transport properties of iron change under extremely high pressure and temperature conditions, such as those found in the Earth's core, is a major experimental challenge. Over the past decade, there has been a great deal of discussion and debate surrounding the thermal conductivity of the iron-based Earth's core and its thermal evolution. One reason for this may be the variability in the experimentally obtained thermal conductivity of iron at high pressures and temperatures. In this study, we present the experimental results of measuring the thermal conductivity of hexagonal-closed-pack (hcp) iron over a wide pressure-temperature range up to 176 GPa and 2900 K using the pulsed light heating thermoreflectance technique in a laser-heated diamond anvil cell. Our findings indicate that the temperature derivative of the thermal conductivity of hcp iron undergoes a change from negative to positive above 74 GPa, potentially making hcp iron highly conductive at conditions similar to those observed in the Earth's core. This observation represents a notable example of a phenomenon where pressure appears to influence the sign of the temperature derivative of the thermal conductivity of an isostructural metal.
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BACKGROUND: Spinal subarachnoid hematoma of unknown origin is rare. Superficial siderosis has been associated with chronic bleeding from spinal dural defects; however, the relationship between these defects and spinal subarachnoid hematoma remains unclear. OBSERVATIONS: A 32-year-old woman presenting with severe back pain and leg weakness exhibited an extensive thoracic spinal hematoma with spinal cord compression on magnetic resonance imaging. Emergency surgery was performed, which revealed a ventral subarachnoid hematoma that was evacuated. A ventral dural defect at the hematoma site and venous bleeding from the surrounding area were observed. Hemostasis was achieved and the defect closed. After surgery, her neurological symptoms quickly resolved. Postoperative spinal angiography showed no vascular lesions. LESSONS: Like superficial siderosis, ventral spinal subarachnoid hematoma can be caused by a spinal dural defect. https://thejns.org/doi/10.3171/CASE24435.
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RATIONALE: Pyogenic spondylodiscitis is an infectious spinal disease that causes significant motor dysfunctions. Its diagnosis can be challenging owing to its rapid onset and nonspecific symptoms. PATIENT CONCERNS: A 79-year-old Japanese man with a history of type 2 diabetes mellitus and polymyalgia rheumatica presented to our department with tongue pain. Following partial glossectomy and wisdom tooth extraction under general anesthesia, on 10 postoperative day (POD) the patient developed right-sided abdominal pain and difficulty in walking. On 12 POD, the patient was admitted to a municipal hospital due to respiratory distress and paraplegia. DIAGNOSES: The patient was diagnosed with pyogenic spondylodiscitis and empyema. Blood tests revealed elevated C-reactive protein levels (36.5), white blood cell count (19,570), and neutrophil count (17,867). INTERVENTIONS: The patient received meropenem hydrate 3 g/2 days as empiric antibiotic treatment for acute infection. Upon admission to the emergency department on 16 POD, the lung abscess was drained, hemilaminectomy was performed. OUTCOMES: Blood cultures, sputum tests, and cultures from the thoracic and spinal abscesses drained during surgery revealed methicillin-sensitive Staphylococcus aureus. The infection was successfully managed, and the respiratory disturbance and inflammatory response improved. However, the lower half of the patient body remained paralyzed. Subsequently, the patient was transferred to a rehabilitation facility on 45 POD. The patient continued to undergo functional restoration training, gradually regained function, and eventually achieved the ability to walk with grasping gait. LESSONS: This is the first case report of S aureus causing pyogenic spondylodiscitis and empyema due to blood stream infection from a post-oral surgical wound. Pyogenic spondylodiscitis arising from a secondary hematogenous infection is difficult to diagnose and can lead to severe functional impairment. Prompt and appropriate diagnosis and treatment based on detailed patient interviews, additional blood tests, and computed tomography are essential.