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Paraspeckles are constructed by NEAT1_2 architectural long noncoding RNAs. Their characteristic cylindrical shapes, with highly ordered internal organization, distinguish them from typical liquid-liquid phase-separated condensates. We experimentally and theoretically investigated how the shape and organization of paraspeckles are determined. We identified the NEAT1_2 RNA domains responsible for shell localization of the NEAT1_2 ends, which determine the characteristic internal organization. Using the soft matter physics, we then applied a theoretical framework to understand the principles that determine NEAT1_2 organization as well as shape, number, and size of paraspeckles. By treating paraspeckles as amphipathic block copolymer micelles, we could explain and predict the experimentally observed behaviors of paraspeckles upon NEAT1_2 domain deletions or transcriptional modulation. Thus, we propose that paraspeckles are block copolymer micelles assembled through a type of microphase separation, micellization. This work provides an experiment-based theoretical framework for the concept that ribonucleoprotein complexes (RNPs) can act as block copolymers to form RNA-scaffolding biomolecular condensates with optimal sizes and structures in cells.
Assuntos
Micelas , Polímeros , RNA Longo não Codificante , Ribonucleoproteínas , Linhagem Celular , HumanosRESUMO
Application of physical forces, ranging from ultrasound to electric fields, is recommended in various clinical practice guidelines, including those for treating cancers and bone fractures. However, the mechanistic details of such treatments are often inadequately understood, primarily due to the absence of comprehensive study models. In this study, we demonstrate that an alternating magnetic field (AMF) inherently possesses a direct anti-cancer effect by enhancing oxidative phosphorylation (OXPHOS) and thereby inducing metabolic reprogramming. We observed that the proliferation of human glioblastoma multiforme (GBM) cells (U87 and LN229) was inhibited upon exposure to AMF within a specific narrow frequency range, including around 227 kHz. In contrast, this exposure did not affect normal human astrocytes (NHA). Additionally, in mouse models implanted with human GBM cells in the brain, daily exposure to AMF for 30 min over 21 days significantly suppressed tumor growth and prolonged overall survival. This effect was associated with heightened reactive oxygen species (ROS) production and increased manganese superoxide dismutase (MnSOD) expression. The anti-cancer efficacy of AMF was diminished by either a mitochondrial complex IV inhibitor or a ROS scavenger. Along with these observations, there was a decrease in the extracellular acidification rate (ECAR) and an increase in the oxygen consumption rate (OCR). This suggests that AMF-induced metabolic reprogramming occurs in GBM cells but not in normal cells. Our results suggest that AMF exposure may offer a straightforward strategy to inhibit cancer cell growth by leveraging oxidative stress through metabolic reprogramming.
Assuntos
Neoplasias Encefálicas , Proliferação de Células , Glioblastoma , Magnetoterapia , Reprogramação Metabólica , Fosforilação Oxidativa , Espécies Reativas de Oxigênio , Animais , Humanos , Camundongos , Astrócitos/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Glioblastoma/metabolismo , Glioblastoma/patologia , Magnetoterapia/métodos , Campos Magnéticos , Reprogramação Metabólica/efeitos da radiação , Mitocôndrias/metabolismo , Consumo de Oxigênio , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Whether in ant-aphid mutualism the ants exert evolutionary selection pressure on aphid morphology has not yet been fully tested. Here, we tested whether the long proboscises of Stomaphis yanonis (Aphididae Lachninae) aphids confer an advantage in preventing predation by the tending ants. Specifically, we tested the hypothesis that aphids with a shorter proboscis would excrete less honeydew, making them more likely to be preyed upon by ants. Our results showed that aphid individuals with a shorter proboscis took up less phloem sap and excreted less honeydew than individuals with a longer proboscis. In addition, among aphids with a similar body size, those with a shorter proboscis were more susceptible to predation by ants than those with a longer proboscis. These results suggest that predation by tending ants, by exerting selection pressure on aphid proboscis morphology, has caused the aphids to evolve longer proboscises.
Assuntos
Formigas , Afídeos , Comportamento Predatório , Animais , Afídeos/fisiologia , Formigas/fisiologia , Comportamento Predatório/fisiologia , Simbiose/fisiologiaRESUMO
BACKGROUND: Fractional flow reserve-computed tomography (FFRCT) has not been validated in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) for coronary artery disease due to theoretical difficulties in using nitroglycerin for such patients.MethodsâandâResults: In this single-center study, we prospectively enrolled 21 patients (34 vessels) and performed pre-TAVR FFRCTwithout nitroglycerin, pre-TAVR invasive instantaneous wave-free ratio (iFR) measurements, and post-TAVR FFR measurements using a pressure wire. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of pre-TAVR FFRCT≤0.80 to predict post-TAVR invasive FFR ≤0.80 were 82%, 83%, 82%, 71%, and 90%, respectively. A receiver operating characteristic analysis demonstrated an optimal cutoff of 0.78 for pre-TAVR FFRCTto indicate post-TAVR FFR ≤0.80, with an area under the curve (AUC) of 0.84, and the counterpart cutoff of pre-TAVR iFR was 0.89 with an AUC of 0.86. CONCLUSIONS: FFRCTwithout nitroglycerin could be a useful non-invasive imaging modality for assessing the severity of coronary artery lesions in patients with severe AS.
Assuntos
Estenose da Valva Aórtica , Doença da Artéria Coronariana , Estenose Coronária , Reserva Fracionada de Fluxo Miocárdico , Substituição da Valva Aórtica Transcateter , Humanos , Reserva Fracionada de Fluxo Miocárdico/fisiologia , Nitroglicerina , Estenose da Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/cirurgia , Estudos Prospectivos , Doença da Artéria Coronariana/cirurgia , Tomografia Computadorizada por Raios X , Valor Preditivo dos Testes , Vasos Coronários , Isquemia/cirurgia , Angiografia Coronária/métodos , Índice de Gravidade de DoençaRESUMO
BACKGROUND: Various antigen-presenting cells and tumor cells-expressing PD-L1 inhibits antitumor immune responses in the tumor microenvironment. Recently, numerous studies have shown that tumor cell intrinsic PD-L1 also plays important roles in tumor growth and progression. On the other hand, oral squamous cell carcinoma (OSCC) cells overexpress epidermal growth factor receptor (EGFR) and EGFR signal pathway exacerbates tumor progression. Therefore, this study assessed whether tumor-intrinsic PD-L1 facilitates malignant potential of OSCC cells through regulation of EGFR signaling. METHODS: Two OSCC cell lines, SAS and HSC-3, were transfected with PD-L1 and EGFR-specific small interfering RNA (siRNA). Influences of PD-L1 knockdown on malignant potentials of OSCC cells were examined by Cell Counting kit-8 assay, transwell assay, sphere formation assay, flow cytometry, and Western blot. Effects of PD-L1 and EGFR knockdown on each expression were examined by quantitative real-time PCR (qRT-PCR), Western blot, and flow cytometry. RESULTS: Transfection of an PD-L1-siRNA into OSCC cells decreased the abilities of proliferation, stemness, and mobility of these cells significantly. PD-L1 knockdown also decreased EGFR expression through the promotion of proteasome- and lysosome-mediated degradation and following activation of the EGFR/protekin kinase B (AKT) signal pathway. Meanwhile, EGFR knockdown did not influence PD-L1 expression in SAS and HSC-3 cells, but treatment with a recombinant human EGF induced its expression. Treatment with erlotinib and cetuximab suppressed rhEGF-induced PD-L1 expression and localization in the cellular membrane of both OSCC cells. CONCLUSION: OSCC cells-expressing PD-L1 induced by EGF stimulation may promote malignancy intrinsically via the activation of the EGFR/AKT signaling cascade.
Assuntos
Antígeno B7-H1 , Carcinoma de Células Escamosas , Receptores ErbB , Neoplasias Bucais , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Humanos , Receptores ErbB/metabolismo , Antígeno B7-H1/metabolismo , Neoplasias Bucais/patologia , Neoplasias Bucais/metabolismo , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proliferação de CélulasRESUMO
Motivation facilitates motor performance; however, the neural substrates of the psychological effects on motor performance remain unclear. We conducted a functional magnetic resonance imaging experiment while human subjects performed a ready-set-go task with monetary incentives. Although subjects were only motivated to respond quickly, increasing the incentives improved not only reaction time but also peak grip force. However, the trial-by-trial correlation between reaction time and peak grip force was weak. Extensive areas in the mesocortical system, including the ventral midbrain (VM) and cortical motor-related areas, exhibited motivation-dependent activity in the premovement "Ready" period when the anticipated monetary reward was displayed. This premovement activity in the mesocortical system correlated only with subsequent peak grip force, whereas the activity in motor-related areas alone was associated with subsequent reaction time and peak grip force. These findings suggest that the mesocortical system linking the VM and motor-related regions plays a role in controlling the peak of force generation indirectly associated with incentives but not the initiation of force generation.
Assuntos
Mapeamento Encefálico , Motivação , Humanos , Mapeamento Encefálico/métodos , Recompensa , Cognição , Tempo de Reação , Imageamento por Ressonância Magnética/métodosRESUMO
BACKGROUND: Murray law-based quantitative flow ratio (µQFR) is a novel computational method that enables accurate estimation of fractional flow reserve (FFR) using a single angiographic projection. However, its diagnostic value in patients with severe aortic stenosis (AS) remains unclear. METHOD: We included 25 consecutive patients who underwent transcatheter aortic valve replacement (TAVR) for severe AS with intermediate or greater (30-90%) coronary artery disease (CAD). Pre- and post-TAVR µQFR, QFR, instantaneous flow reserve (iFR), and post-TAVR invasive FFR values were measured. We evaluated the diagnostic performance of pre-TAVR µQFR, QFR, and iFR using post-TAVR FFR ≤ 0.80 as a reference standard of ischemia. RESULT: Pre-TAVR µQFR was significantly correlated with post-TAVR FFR (r = 0.73, p < 0.0001). The area under the curve of pre-TAVR µQFR on post-TAVR FFR ≤ 0.8 was 0.91 (95% confidence interval [CI] 0.77-0.98), comparable to that of pre-TAVR iFR (0.86 [95% CI 0.71-0.98], p = 0.97). The accuracy, sensitivity, specificity, and positive and negative predictive values of pre-TAVR µQFR on post-TAVR FFR ≤ 0.8 were 84.2% (95% CI 68.7-93.4), 61.6% (95% CI 31.6-86.1), 96.0% (95% CI 79.6-99.9), 88.9% (95% CI 52.9-98.3), and 82.8% (95% CI 70.6-90.6), respectively. For pre-TAVR iFR, these values were 76.5% (95% CI 58.8-89.3), 90.9% (95% CI 58.7-99.8), 69.6% (95% CI 47.1-86.8), 58.8% (95% CI 42.8-73.1), and 94.1% (95% CI 70.8-99.1), respectively. CONCLUSION: µQFR could be useful for the physiological evaluation of patients with severe AS with concomitant CAD.
Assuntos
Estenose da Valva Aórtica , Valva Aórtica , Angiografia Coronária , Reserva Fracionada de Fluxo Miocárdico , Índice de Gravidade de Doença , Substituição da Valva Aórtica Transcateter , Humanos , Estenose da Valva Aórtica/cirurgia , Estenose da Valva Aórtica/fisiopatologia , Estenose da Valva Aórtica/diagnóstico , Masculino , Feminino , Reserva Fracionada de Fluxo Miocárdico/fisiologia , Idoso de 80 Anos ou mais , Idoso , Valva Aórtica/cirurgia , Valva Aórtica/fisiopatologia , Valva Aórtica/diagnóstico por imagem , Estudos Retrospectivos , Reprodutibilidade dos Testes , Valor Preditivo dos Testes , Vasos Coronários/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/fisiopatologia , Doença da Artéria Coronariana/cirurgiaRESUMO
BACKGROUND: We investigate whether Intensive uric acid (UA)-lowering therapy (ULT) provides increased renal protection compared with standard therapy in chronic kidney disease (CKD) patients. METHODS: This was a multicenter randomized controlled trial. Only CKD patients with hyperuricemia were included in this study. The participants were randomly assigned to either the Intensive therapy group (target serum UA level ≥ 4.0 mg/dL and < 5.0 mg/dL) or the standard therapy group (serum UA level ≥ 6.0 mg/dL and < 7.0 mg/dL). ULT was performed using topiroxostat, a non-purine-type selective xanthine oxidase inhibitor. The primary endpoint was change in the logarithmic value of urine albumin to the creatinine ratio (ACR) between baseline and week 52 of the treatment. RESULTS: Three hundred fifty-two patients were included in the full analysis set. In the Standard therapy group, mean serum UA was 8.23 mg/dL at baseline and 6.13 mg/dL at 52 weeks. In the Intensive therapy group, mean serum UA was 8.15 mg/dL at baseline and 5.25 mg/dL at 52 weeks. There was no significant difference in changes in log ACR at 52 weeks between the Intensive therapy and the Standard therapy groups. CONCLUSION: This study did not reveal the benefit of Intensive ULT to improve albuminuria levels. (UMIN000026741 and jRCTs051180146).
Assuntos
Albuminúria , Hiperuricemia , Insuficiência Renal Crônica , Ácido Úrico , Humanos , Hiperuricemia/tratamento farmacológico , Hiperuricemia/complicações , Hiperuricemia/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Ácido Úrico/sangue , Idoso , Albuminúria/tratamento farmacológico , Creatinina/sangue , Creatinina/urina , Resultado do Tratamento , Xantina Oxidase/antagonistas & inibidores , Nitrilas/uso terapêutico , Biomarcadores/sangue , Biomarcadores/urina , PiridinasRESUMO
PURPOSE: To evaluate the long-term efficacy and safety of ripasudil-brimonidine fixed-dose combination (RBFC), a new intraocular pressure (IOP)-lowering medication for glaucoma and ocular hypertension (OHT). METHODS: This prospective, multicentre (23 sites in Japan), open-label study enrolled patients with primary open-angle glaucoma (POAG), OHT or exfoliative glaucoma and assigned them to one of four combination therapy cohorts, based on previous treatment(s) received: prostaglandin (PG) analogue (Cohort 1); PG analogue and beta-adrenoceptor blocker (ß-blocker) (Cohort 2); PG analogue, ß-blocker and carbonic anhydrase inhibitor (Cohort 3); or other/no treatment (Cohort 4). After a ≥ 4-week screening period, eligible patients received twice-daily RBFC for 52 weeks in addition to the treatments they were already receiving. Efficacy was assessed by change in IOP from baseline through week 52. Adverse events and adverse drug reactions (ADRs) were monitored throughout. RESULTS: In total, 179 patients from Cohort 1 (n = 48), Cohort 2 (n = 44), Cohort 3 (n = 41) and Cohort 4 (n = 46) entered the RBFC treatment period. For all cohorts, mean IOP was significantly reduced at 11:00 (2 h after instillation of RBFC) through week 52 with the changes from baseline at week 52 of - 2.7 to - 4.1 mmHg across cohorts; all p < 0.001. Common ADRs were conjunctival hyperaemia (58%), allergic conjunctivitis (18%) and blepharitis (17%), most of which were mild in severity. CONCLUSION: These data demonstrated the long-term efficacy and safety of RBFC, both alone and in combination with other anti-glaucoma agents. RBFC may offer a new treatment option for the long-term management of glaucoma and OHT. TRIAL REGISTRATION: Japan Registry of Clinical Trials Identifier: jRCT2080225063. DATE OF REGISTRATION: 17 February 2020.
Assuntos
Anti-Hipertensivos , Tartarato de Brimonidina , Pressão Intraocular , Isoquinolinas , Hipertensão Ocular , Sulfonamidas , Humanos , Pressão Intraocular/efeitos dos fármacos , Pressão Intraocular/fisiologia , Hipertensão Ocular/tratamento farmacológico , Hipertensão Ocular/fisiopatologia , Hipertensão Ocular/diagnóstico , Masculino , Feminino , Estudos Prospectivos , Idoso , Sulfonamidas/administração & dosagem , Sulfonamidas/efeitos adversos , Isoquinolinas/administração & dosagem , Isoquinolinas/efeitos adversos , Tartarato de Brimonidina/administração & dosagem , Resultado do Tratamento , Pessoa de Meia-Idade , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/efeitos adversos , Seguimentos , Soluções Oftálmicas , Fatores de Tempo , Relação Dose-Resposta a Droga , Tonometria Ocular , Combinação de Medicamentos , Glaucoma de Ângulo Aberto/tratamento farmacológico , Glaucoma de Ângulo Aberto/fisiopatologiaRESUMO
BACKGROUND: Electronic gambling machines (EGMs) in gambling venues cause gambling-related harm and are a public health concern. This study focused on pachinko parlours as gambling venues and income-generating crimes as gambling-related harm. We aimed to verify whether income-generating crime rates increase in proximity to pachinko parlours and during the opening and post-closing periods of pachinko parlours relative to the pre-opening periods. METHODS: We used crime records spanning 6.5 years, including data on the opening and closing days of pachinko parlours for 6.5 years. We also sampled the addresses of convenience stores, bowling alleys, and households with official land prices all over Japan. The dependent variable was the daily income-generating crime incidence rate. Areas within 0.5 km, 0.5-1 km, 1-5 km, and 5-10 km radii of the pachinko parlours were the independent variables. The pre-, opening-, and post-closing periods of the pachinko parlours were also independent variables. The covariates included the number of convenience stores and always open pachinko parlours near pachinko parlours. Data were analysed using an analysis of variance (ANOVA) and covariance (ANCOVA). We also used differences-in-differences analysis (DD) to reveal the increase in income-generating crime rates in neighbourhoods exposed to the opening or closing of pachinko parlours. RESULTS: The daily income-generating crime incidence rate was significantly higher in areas within 0.5-1 km and 1-5 km radii of pachinko parlours than in those within 0.5 km and 5-10 km radii of them. The daily income-generating crime incidence rate was also significantly higher during the opening and post-closing periods than during the pre-opening period, even when controlling for the number of convenience stores and always open pachinko parlours. In particular, fraud crime rates increased with the opening and closing of pachinko parlours. CONCLUSIONS: The highest income-generating crime incidence rate was observed within a 0.5-1 km and 1-5 km radius of pachinko parlours. The opening of pachinko parlours also increased income-generating crime incidence rates, which increased after closing. Pachinko parlours are considered to be creating public harm because the corporate activities of these parlours make the youth in their neighbourhood perpetrators of fraud and older adults its victims. Future research should examine the current findings using official crime records.
Assuntos
Crime , Jogo de Azar , Renda , Características de Residência , Japão/epidemiologia , Humanos , Crime/estatística & dados numéricos , Jogo de Azar/epidemiologia , Características de Residência/estatística & dados numéricos , Renda/estatística & dados numéricosRESUMO
BACKGROUND: Takotsubo cardiomyopathy (TC) is a well-known complication of subarachnoid haemorrhage (SAH), often accompanied by neurogenic myocardial dysfunction. Although TC has been reported to be associated with higher morbidity and mortality among patients with aneurysmal SAH (aSAH), some patients have been reported to recover, the profiles and follow-up outcomes of these survivors remain unclear. MATERIALS AND METHODS: To characterize the profiles of patients with aSAH complicated by TC who experienced favourable outcomes using long-term follow-up data, a consecutive series of patients with aSAH were enrolled and TC diagnosis was based on the revised version of the Mayo Clinic criteria. Clinical outcomes were assessed at 6 months according to modified Rankin Scale scores. RESULTS: Among 165 consecutive patients with aSAH, 15 cases were complicated by TC, corresponding to an occurrence rate of 9.0%. Five patients with aSAH complicated by TC (33.3%) experienced a favourable outcome, and the mean value of systolic blood pressure on arrival was significantly lower than in those who experienced an unfavourable outcome (p = 0.032). CONCLUSION: According to analysis, it is possible cardiac dysfunction with decreased cerebral perfusion pressure and catecholamine toxicity transiently worsens conscious disturbance in aSAH complicated by TC. Therefore, it is important to carefully screen patients with aSAH to identify those complicated by TC, and for close collaboration of the multidisciplinary team to design appropriate treatment strategies.
RESUMO
Photodynamic therapy (PDT) is useful for various cancers such as high-grade glioma and cancers of other organs. However, the mechanism of tumor-specific accumulation of porphyrin is not clear. The authors previously reported that heme carrier protein 1 (HCP1) contributes to the transport of porphyrins; specifically, we showed that the production of cancer-specific reactive oxygen species from mitochondria (mitROS) leads in turn to enhanced HCP1 expression. Indomethacin (IND), a non-steroidal anti-inflammatory drug, increases ROS production by affecting mitochondrial electron transfer system. In the present work, the authors investigated the effect of pretreatment with IND on cancer-specific porphyrin accumulation, using both a glioma cell line and a rat brain tumor model. This work demonstrated that exposure of a rat glioma cell to IND results in increased generation of cancer-specific mitROS and accumulation of HCP1 expression and porphyrin concentration. Additionally, systemic dosing of a brain tumor animal model with IND resulted in elevated cellular accumulation of porphyrin in tumor cell. This is an effect not seen with normal brain tissue. Thus, the administration of IND increases intracellular porphyrin concentrations in tumor cell without exerting harmful effects on normal brain tissue, and increased porphyrin concentration in tumor cell may lead to improved PDT effect.
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This article describes the concept and technical aspects of the occipital transtentorial approach(OTA)for tumor extraction in the pineal region, based on the author's experience and literature review. Awareness of the successful completion of each surgical step is essential. Preoperative preparation and imaging evaluations, with particular attention to the veins and venous sinuses, are especially important. It is also helpful to perform a complete dura incision and inversion up to the edge of confluence, superior sagittal sinus, and transverse sinus. Subsequently, it is necessary to understand the usefulness of adequate dissection in the vicinity of the corpus callosum and internal occipital vein(IOV)so that the occipital lobe can be moved without difficulty. Furthermore, development of the IOV with adequate tentoriotomy facilitates contralateral work. Finally, complete understanding of each step during the bilateral, ambient cistern and cerebellomesencephalic fissure dissection process, where the cerebellar vermis can be moved without difficulty, is necessary for a safe OTA to pineal region tumor extraction.
Assuntos
Procedimentos Neurocirúrgicos , Glândula Pineal , Pinealoma , Humanos , Procedimentos Neurocirúrgicos/métodos , Pinealoma/cirurgia , Glândula Pineal/cirurgia , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/diagnóstico por imagemRESUMO
Condensin-mediated loop extrusion is now considered as the main driving force of mitotic chromosome assembly. Recent experiments have shown, however, that a class of mutant condensin complexes deficient in loop extrusion can assemble chromosome-like structures in Xenopus egg extracts, although these structures are somewhat different from those assembled by wild-type condensin complexes. In the absence of topoisomerase II (topo II), the mutant condensin complexes produce an unusual round-shaped structure termed a bean, which consists of a DNA-dense central core surrounded by a DNA-sparse halo. The mutant condensin complexes accumulate in the core, whereas histones are more concentrated in the halo than in the core. We consider that this peculiar structure serves as a model system to study how DNA entanglements, nucleosomes, and condensin functionally crosstalk with each other. To gain insight into how the bean structure is formed, here we construct a theoretical model. Our theory predicts that the core is formed by attractive interactions between mutant condensin complexes, whereas the halo is stabilized by the energy reduction through the selective accumulation of nucleosomes. The formation of the halo increases the elastic free energy due to the DNA entanglement in the core, but the latter free energy is compensated by condensin complexes that suppress the assembly of nucleosomes.
Assuntos
Mitose , Nucleossomos , Cromossomos , DNA/genética , ElasticidadeRESUMO
Hyperuricemia is a metabolic disease caused by purine nucleotide metabolism disorder. The prevalence of hyperuricemia is increasing worldwide, with a growing trend in the younger populations. Although numerous studies have indicated that hyperuricemia may be an independent risk factor for insulin resistance, the causal relationship between the two is controversial. There are few reviews, however, focusing on the relationship between uric acid (UA) and insulin resistance from experimental studies. In this review, we summarized the experimental models related to soluble UA-induced insulin resistance in pancreas and peripheral tissues, including skeletal muscles, adipose tissue, liver, heart/cardiomyocytes, vascular endothelial cells and macrophages. In addition, we summarized the research advances about the key mechanism of UA-induced insulin resistance. Moreover, we attempt to identify novel targets for the treatment of hyperuricemia-related insulin resistance. Lastly, we hope that the present review will encourage further researches to solve the chicken-and-egg dilemma between UA and insulin resistance, and provide strategies for the pathogenesis and treatment of hyperuricemia related metabolic diseases.
Assuntos
Hiperuricemia , Resistência à Insulina , Humanos , Ácido Úrico/metabolismo , Insulina , Hiperuricemia/metabolismo , Células Endoteliais/metabolismoRESUMO
Pre-ribosomal RNAs are synthesized during the transcription by RNA polymerase I molecules localized at the surfaces of a nucleolus subcompartment. Inspired by the ribosomal RNA transcription, we here develop a scaling theory of a brush of polymers, where monomers are added to their grafted ends in the steady state. Our theory predicts that monomers newly added to the polymers stay at the vicinity of the surface due to the slow dynamics of the polymers and thus the polymer volume fraction increases with increasing the polymerization rate. The excluded volume interaction between polymers and reactant monomers suppresses the diffusion of reactant monomers and thus decreases the polymerization rate. The extent of the suppression of monomer diffusion increases with increasing the polymerization rate because the diffusion length decreases, rather than the condensation of polymers due to their slow dynamics.
Assuntos
Transcrição Gênica , RNA Ribossômico/genética , Modelos GenéticosRESUMO
It is important to understand the dynamics of red blood cells (RBCs) in blood flow. This requires the formulation of coarse-grained RBC models that reproduce the hydrodynamic properties of blood accurately. One of the models that successfully reproduces the rheology and morphology of blood has been proposed by Fedosov et al. [Comput. Methods Appl. Mech. Eng. 199, 1937-1948 (2010)]. The proposed RBC model contains several parameters whose values are determined by either various experiments or physical requirements. In this study, we developed a new method of determining parameter values precisely from the fluctuations of the RBC membrane. Specifically, we studied the relationship between the spectra of the fluctuations and model parameters. Characteristic peaks were observed in the spectra, whose peak frequencies were dependent on the parameter values. In addition, we investigated the spectra of the radius of gyration. We identified the peaks originating from the spring potential and the volume-conserving potential appearing in the spectra. These results lead to the precise experimental determination of the parameters used in the RBC model.
Assuntos
Eritrócitos , Eritrócitos/metabolismo , Reologia/métodos , Análise EspectralRESUMO
In angiosperms, intraspecific variation of flowering phenology may affect reproductive isolation and, consequently, speciation. This study focused on Impatiens noli-tangere (Balsaminaceae), which is distributed over broad latitudinal and altitudinal ranges in Japan. We aimed to reveal the phenotypic mixture of two ecotypes of I. noli-tangere with different flowering phenology and morphological traits in a narrow contact zone. Previous studies have shown that I. noli-tangere has early- and late-flowering types. The early-flowering type makes buds in June and is distributed at high-elevation sites. The late-flowering type makes buds in July and is distributed at low-elevation sites. In this study, we analyzed the flowering phenology of individuals at an intermediate elevation site where the early- and late-flowering types grow in sympatry (contact zone). We found no individuals showing intermediate flowering phenology at the contact zone, and early- and late-flowering types were clearly distinguishable. We also found that the differences in many other phenotypic traits between the early- and late-flowering types were maintained, including the number of flowers produced (total number of chasmogamous and cleistogamous flowers), leaf morphology (aspect ratio, number of serrations), seed traits (aspect ratio), and flower bud formation positions on the plant. This study showed that these two flowering ecotypes maintain many different traits in sympatry.
Assuntos
Balsaminaceae , Impatiens , Ecótipo , Simpatria , Reprodução , FloresRESUMO
Enhancers are DNA sequences at a long genomic distance from target genes. Recent experiments suggest that enhancers are anchored to the surfaces of condensates of transcription machinery and that the loop extrusion process enhances the transcription level of their target genes. Here, we theoretically study the polymer dynamics driven by the loop extrusion of the linker DNA between an enhancer and the promoter of its target gene to calculate the contact probability of the promoter to the transcription machinery in the condensate. Our theory predicts that when the loop extrusion process is active, the contact probability increases with increasing linker DNA length. This finding reflects the fact that the relaxation time, with which the promoter stays in proximity to the surface of the transcriptional condensate, increases as the length of the linker DNA increases. This contrasts the equilibrium case for which the contact probability between the promoter and the transcription machineries is smaller for longer linker DNA lengths.
Assuntos
Cromatina/química , Regiões Promotoras Genéticas , Transcrição Gênica , DNA/química , Elementos Facilitadores GenéticosRESUMO
BACKGROUND: Optimal hemostasis provides safety and reliability during neurosurgery which improves surgical outcomes. Previously, artificial cerebrospinal fluid (aCSF) and its component sodium bicarbonate were found to facilitate physiological hemostasis by amplifying platelet aggregation. This study aimed to verify whether aCSF amplifies platelet-dependent hemostasis in the presence of antiplatelet agents. METHODS: We prepared platelet-rich plasma (PRP) or washed platelets using aspirin (acetylsalicylic acid, (ASA)) or normal saline (NS). We evaluated samples treated with a commercially available aCSF solution or NS for amplification of aggregation, activation of integrin αIIbß3, phosphatidylserine (PS) exposure, P-selectin (CD62P) expression, and formation of microparticles (MPs). We assessed the effect of aCSF on in vivo hemostasis in the presence of ASA by measuring the tail bleeding time in ASA-or NS-injected C57BL/6 N mice. RESULTS: Compared with NS, aCSF amplified ASA-inhibited platelet aggregation by recovering platelet activation including PS exposure, MP release, CD62P expression, and integrin αIIbß3 activation. When using washed platelets, aCSF almost completely counteracted the inhibition of platelet aggregation by ASA. Prolonged bleeding time from the amputated tail of ASA-injected mice was significantly shortened by the treatment with aCSF compared to NS. Sodium bicarbonate also directly amplified ASA-inhibited platelet aggregation. CONCLUSIONS: aCSF and sodium bicarbonate facilitate physiological hemostasis through the recovery of inhibited platelet aggregation even in the presence of ASA. The utilization of aCSF in the operative field may be advantageous for facilitating hemostasis in patients with impaired platelet function and contribute to improving outcomes of neurosurgery.