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Phosphorothioate (PT)-modification was discovered in prokaryotes and is involved in many biological functions such as restriction-modification systems. PT-modification can be recognized by the sulfur binding domains (SBDs) of PT-dependent restriction endonucleases, through coordination with the sulfur atom, accompanied by interactions with the DNA backbone and bases. The unique characteristics of PT recognition endow SBDs with the potential to be developed into gene-targeting tools, but previously reported SBDs display sequence-specificity for PT-DNA, which limits their applications. In this work, we identified a novel sequence-promiscuous SBDHga from Hahella ganghwensis. We solved the crystal structure of SBDHga complexed with PT-DNA substrate to 1.8 Å resolution and revealed the recognition mechanism. A shorter L4 loop of SBDHga interacts with the DNA backbone, in contrast with previously reported SBDs, which interact with DNA bases. Furthermore, we explored the feasibility of using SBDHga and a PT-oligonucleotide as targeting tools for site-directed adenosine-to-inosine (A-to-I) RNA editing. A GFP non-sense mutant RNA was repaired at about 60% by harnessing a chimeric SBD-hADAR2DD (deaminase domain of human adenosine deaminase acting on RNA), comparable with currently available RNA editing techniques. This work provides insights into understanding the mechanism of sequence-specificity for SBDs and for developing new tools for gene therapy.
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Edición de ARN , Humanos , Adenosina Desaminasa/metabolismo , ADN/química , Edición Génica , ARN/metabolismo , Azufre/químicaRESUMEN
Microorganisms in the human body have a great impact on human health. Therefore, mastering the potential relationship between microorganisms and diseases is helpful to understand the pathogenesis of diseases and is of great significance to the prevention, diagnosis, and treatment of diseases. In order to predict the potential microbial disease relationship, we propose a new computational model. Firstly, a bi-directional heterogeneous microbial disease network is constructed by integrating multiple similarities, including Gaussian kernel similarity, microbial function similarity, disease semantic similarity, and disease symptom similarity. Secondly, the neighbor information of the network is learned by random walk; Finally, the selection model is used for information aggregation, and the microbial disease node pair is analyzed. Our method is superior to the existing methods in leave-one-out cross-validation and five-fold cross-validation. Moreover, in case studies of different diseases, our method was proven to be effective.
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Algoritmos , Biología Computacional , Humanos , Biología Computacional/métodos , SemánticaRESUMEN
The sulfur atom of phosphorothioated DNA (PT-DNA) is coordinated by a surface cavity in the conserved sulfur-binding domain (SBD) of type IV restriction enzymes. However, some SBDs cannot recognize the sulfur atom in some sequence contexts. To illustrate the structural determinants for sequence specificity, we resolved the structure of SBDSpr, from endonuclease SprMcrA, in complex with DNA of GPSGCC, GPSATC and GPSAAC contexts. Structural and computational analyses explained why it binds the above PT-DNAs with an affinity in a decreasing order. The structural analysis of SBDSpr-GPSGCC and SBDSco-GPSGCC, the latter only recognizes DNA of GPSGCC, revealed that a positively charged loop above the sulfur-coordination cavity electrostatically interacts with the neighboring DNA phosphate linkage. The structural analysis indicated that the DNA-protein hydrogen bonding pattern and weak non-bonded interaction played important roles in sequence specificity of SBD protein. Exchanges of the positively-charged amino acid residues with the negatively-charged residues in the loop would enable SBDSco to extend recognization for more PT-DNA sequences, implying that type IV endonucleases can be engineered to recognize PT-DNA in novel target sequences.
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Enzimas de Restricción del ADN/genética , Proteínas de Unión al ADN/genética , ADN/genética , Azufre/química , Secuencia de Aminoácidos/genética , Cristalografía por Rayos X , ADN/química , Enzimas de Restricción del ADN/química , Proteínas de Unión al ADN/química , Escherichia coli/genética , Enlace de Hidrógeno , Unión Proteica/genética , Dominios Proteicos/genética , Streptomyces/enzimologíaRESUMEN
Oxidative stress induced by long-term cyclosporine A (CsA) administration is a major cause of chronic nephrotoxicity, which is characterized by tubular atrophy, tubular cell apoptosis, and interstitial fibrosis in the progression of organ transplantation. Although hydrogen-rich water (HRW) has been used to prevent various oxidative stress-related diseases, its underlying mechanisms remain unclear. This study investigated the effects of HRW on CsA-induced nephrotoxicity and its potential mechanisms. After administration of CsA (25 mg/kg/day), rats were treated with or without HRW (12 mL/kg) for 4 weeks. Renal function and vascular activity were investigated. Histological changes in kidney tissues were analyzed using Masson's trichrome and terminal deoxynucleotidyl transferase dUTP nick-end labeling stains. Oxidative stress markers and the activation of the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway were also measured. We found that CsA increased the levels of reactive oxygen species (ROS) and malonaldehyde (MDA), but it reduced glutathione (GSH) and superoxide dismutase (SOD) levels. Such alterations induced vascular dysfunction, tubular atrophy, interstitial fibrosis, and tubular apoptosis. This was evident secondary to an increase in urinary protein, serum creatinine, and blood urea nitrogen, ultimately leading to renal dysfunction. Conversely, HRW decreased levels of ROS and MDA while increasing the activity of GSH and SOD. This was accompanied by an improvement in vascular and renal function. Moreover, HRW significantly decreased the level of Keap1 and increased the expression of Nrf2, NADPH dehydrogenase quinone 1, and heme oxygenase 1. In conclusion, HRW restored the balance of redox status, suppressed oxidative stress damage, and improved kidney function induced by CsA via activation of the Keap1/Nrf2 signaling pathway.
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Ciclosporina/efectos adversos , Hidrógeno/farmacología , Inmunosupresores/efectos adversos , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Sustancias Protectoras/farmacología , Insuficiencia Renal/inducido químicamente , Transducción de Señal/efectos de los fármacos , Agua/farmacología , Animales , Apoptosis/efectos de los fármacos , Nitrógeno de la Urea Sanguínea , Creatinina/sangre , Creatinina/orina , Masculino , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Insuficiencia Renal/orina , Superóxido Dismutasa/metabolismo , Agua/químicaRESUMEN
Streptomyces species have been valuable models for understanding the phenomenon of DNA phosphorothioation in which sulfur replaces a non-bridging oxygen in the phosphate backbone of DNA. We previously reported that the restriction endonuclease ScoMcrA from Streptomyces coelicolor cleaves phosphorothioate DNA and Dcm-methylated DNA at sites 16-28 nucleotides away from the modification sites. However, cleavage of modified DNA by ScoMcrA is always incomplete and accompanied by severe promiscuous activity on unmodified DNA. These features complicate the studies of recognition and cleavage of phosphorothioate DNA. For these reasons, we here characterized SprMcrA from Streptomyces pristinaespiralis, a much smaller homolog of ScoMcrA with a rare HRH motif, a variant of the HNH motif that forms the catalytic center of these endonucleases. The sulfur-binding domain of SprMcrA and its phosphorothioation recognition site were determined. Compared to ScoMcrA, SprMcrA has higher specificity in discerning phosphorothioate DNA from unmodified DNA, and this enzyme generally cuts both strands at a distance of 11-14 nucleotides from the 5' side of the recognition site. The HRH/HNH motif has its own sequence specificity in DNA hydrolysis, leading to failure of cleavage at some phosphorothioated sites. An R248N mutation of the central residue in HRH resulted in 30-fold enhancement in cleavage activity of phosphorothioate DNA and altered the cleavage efficiency at some sites, whereas mutation of both His residues abolished restriction activity. This is the first report of a recognition domain for phosphorothioate DNA and phosphorothioate-dependent and sequence-specific restriction activity.
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Enzimas de Restricción del ADN/metabolismo , ADN Bacteriano/metabolismo , Streptomyces/enzimología , Azufre/metabolismo , Sitios de Unión , Unión ProteicaRESUMEN
The purpose of this paper is to analyze the properties of porcine cartilage type II collagen scaffolds crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxy-succinamide (EDC/NHS) under different conditions. The porous EDC/NHS-crosslinked scaffolds were obtained through a two-step freeze-drying process. To determine the optimal crosslinking condition, we used different solvents and various crosslinking temperatures to prepare the scaffolds. Three crosslinking solutions were prepared with different solvents, photographs were taken with a flash in the darkroom, and light transmission was observed. Type II collagen was crosslinked on a horizontal shaker at a speed of 60 r/min according to the above grouping conditions, and then the structural change of the scaffold in each group was observed. To investigate the swelling ratio and the in vitro degradation of the collagen scaffold, tests were also carried out by immersion of the scaffolds in a PBS solution and digestion in type II collagenase, respectively. The influence of the scaffolds on the proliferation of chondrocytes was assessed by the methyl thiazolyl tetrazolium colorimetric assay. The morphology of the crosslinked scaffolds cocultured with chondrocytes was characterized by a scanning electron microscope. The results proved that 75% alcohol and a crosslinking temperature of 37 °C are recommended. Collagen fibrils are more densely packed after crosslinking with EDC/NHS and have a more uniform structure than that of noncrosslinked ones. The EDC-crosslinked scaffolds possessed excellent mechanical property and biocompatibility.
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Colágeno Tipo II/química , Reactivos de Enlaces Cruzados/química , Succinimidas/química , Andamios del Tejido/química , Animales , Proliferación Celular , Células Cultivadas , Condrocitos/citología , Liofilización , Conejos , Porcinos , Ingeniería de TejidosRESUMEN
The morphological properties of the large scale structure of the Universe can be fully described by four Minkowski functionals (MFs), which provide important complementary information to other statistical observables such as the widely used 2-point statistics in configuration and Fourier spaces. In this work, for the first time, we present the differences in the morphology of the large scale structure caused by modifications to general relativity (to address the cosmic acceleration problem), by measuring the MFs from N-body simulations of modified gravity and general relativity. We find strong statistical power when using the MFs to constrain modified theories of gravity: with a galaxy survey that has survey volume â¼0.125(h^{-1} Gpc)^{3} and galaxy number density â¼1/(h^{-1} Mpc)^{3}, the two normal-branch Dvali-Gabadadze-Porrati models and the F5 f(R) model that we simulated can be discriminated from the ΛCDM model at a significance level â³5σ with an individual MF measurement. Therefore, the MF of the large scale structure is potentially a powerful probe of gravity, and its application to real data deserves active exploration.
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SET and RING-finger-associated (SRA) domain is involved in establishment and maintenance of DNA methylation in eukaryotes. Proteins containing SRA domains exist in mammals, plants, even microorganisms. It has been established that mammalian SRA domain recognizes 5-methylcytosine (5mC) through a base-flipping mechanism. Here, we identified and characterized two SRA domain-containing proteins with the common domain architecture of N-terminal SRA domain and C-terminal HNH nuclease domain, Sco5333 from Streptomyces coelicolor and Tbis1 from Thermobispora bispora. Both sco5333 and tbis1 cannot establish in methylated Escherichia coli hosts (dcm(+)), and this in vivo toxicity requires both SRA and HNH domain. Purified Sco5333 and Tbis1 displayed weak DNA cleavage activity in the presence of Mg(2+), Mn(2+) and Co(2+) and the cleavage activity was suppressed by Zn(2+). Both Sco5333 and Tbis1 bind to 5mC-containing DNA in all sequence contexts and have at least a preference of 100 folds in binding affinity for methylated DNA over non-methylated one. We suggest that linkage of methyl-specific SRA domain and weakly active HNH domain may represent a universal mechanism in competing alien methylated DNA but to maximum extent minimizing damage to its own chromosome.
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5-Metilcitosina/metabolismo , Proteínas Bacterianas/metabolismo , División del ADN , Metilación de ADN , Proteínas de Unión al ADN/metabolismo , Endodesoxirribonucleasas/metabolismo , Actinomycetales , Proteínas Bacterianas/química , Cationes Bivalentes , Proteínas de Unión al ADN/química , Endodesoxirribonucleasas/química , Unión Proteica , Estructura Terciaria de Proteína , Streptomyces coelicolorRESUMEN
In this Letter, we report the observational constraints on the Hu-Sawicki f(R) theory derived from weak lensing peak abundances, which are closely related to the mass function of massive halos. In comparison with studies using optical or x-ray clusters of galaxies, weak lensing peak analyses have the advantages of not relying on mass-baryonic observable calibrations. With observations from the Canada-France-Hawaii-Telescope Lensing Survey, our peak analyses give rise to a tight constraint on the model parameter |f_{R0}| for n=1. The 95% C.L. is log_{10}|f_{R0}|<-4.82 given WMAP9 priors on (Ω_{m}, A_{s}). With Planck15 priors, the corresponding result is log_{10}|f_{R0}|<-5.16.
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Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.
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5-Hydroxymethylcytosine (5hmC) is present in T-even phage and mammalian DNA as well as some nucleoside antibiotics, including mildiomycin and bacimethrin, during whose synthesis 5hmC is produced by the hydrolysis of 5-hydroxymethyl cytidine 5'-monophosphate (hmCMP) by an N-glycosidase MilB. Recently, the MilB-CMP complex structure revealed its substrate specificity for CMP over dCMP. However, hmCMP instead of CMP is the preferred substrate for MilB as supported by that its KM for CMP is â¼27-fold higher than that for hmCMP. Here, we determined the crystal structures of MilB and its catalytically inactive E103A mutant in complex with hmCMP. In the structure of the complex, Phe22 and Arg23 are positioned in a cage-like active site resembling the binding pocket for the flipped 5-methylcytosine (5mC) in eukaryotic 5mC-binding proteins. Van der Waals interaction between the benzene ring of Phe22 and the pyrimidine ring of hmCMP stabilizes its binding. Remarkably, upon hmCMP binding, the guanidinium group of Arg23 was bent â¼65° toward hmCMP to recognize its 5-hydroxymethyl group, inducing semi-closure of the cage-like pocket. Mutagenesis studies of Arg23 and bioinformatics analysis demonstrate that the positively charged Arg/Lys at this site is critical for the specific recognition of the 5-hydroxymethyl group of hmCMP.
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Arginina/química , Citidina Monofosfato/análogos & derivados , Glicósido Hidrolasas/química , Dominio Catalítico , Citidina Monofosfato/química , Citidina Monofosfato/metabolismo , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Modelos Moleculares , Mutación Puntual , Unión Proteica , Especificidad por SustratoRESUMEN
This study aimed to explore the mediating effects of ADL and depression on the relationship between sleep quality and HRQOL among older people in rural China, while also exploring the moderating impact of loneliness. The study gathered data from a household survey conducted among 1587 Chinese rural older adults (mean age = 73.63 years). The collected data was analyzed using SPSS version 23.0 software (IBM, New York, USA) and the PROCESS macro version 4.0 program. The findings indicated a significant correlation between sleep quality, ADL, depression, loneliness and HRQOL. ADL and depression exhibited a chain mediation effect on the relationship between sleep quality and HRQOL. Notably, the association between sleep quality and HRQOL was entirely mediated by ADL and depression. Additionally, loneliness acted as a moderator in the relationship between ADL and HRQOL. The findings of this study suggest that interventions focusing on sleep quality should prioritize strategies for enhancing older adults' ADL and depression as integral components of promoting older adults' HRQOL.
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Actividades Cotidianas , Depresión , Calidad de Vida , Calidad del Sueño , Humanos , Anciano , Depresión/psicología , Masculino , Femenino , Anciano de 80 o más Años , China/epidemiología , Soledad/psicología , Persona de Mediana Edad , Población Rural , Encuestas y CuestionariosRESUMEN
BACKGROUND: Spinal manipulative therapy (SMT) is a guideline-recommended treatment option for spinal pain. The recommendation is based on multiple systematic reviews. However, these reviews fail to consider that clinical effects may depend on SMT "application procedures" (i.e., how and where SMT is applied). Using network meta-analyses, we aim to investigate which SMT "application procedures" have the greatest magnitude of clinical effectiveness for reducing pain and disability, for any spinal complaint, at short-term and long-term follow-up. We will compare application procedural parameters by classifying the thrust application technique and the application site (patient positioning, assisted, vertebral target, region target, Technique name, forces, and vectors, application site selection approach and rationale) against: 1. Waiting list/no treatment; 2. Sham interventions not resembling SMT (e.g., detuned ultrasound); 3. Sham interventions resembling SMT; 4. Other therapies not recommended in clinical practice guidelines; and 5. Other therapies recommended in clinical practice guidelines. Secondly, we will examine how contextual elements, including procedural fidelity (whether the SMT was delivered as planned) and clinical applicability (whether the SMT is similar to clinical practice) of the SMT. METHODS: We will include randomized controlled trials (RCT) found through three search strategies, (i) exploratory, (ii) systematic, and (iii) other known sources. We define SMT as a high-velocity low-amplitude thrust or grade V mobilization. Eligibility is any RCT assessing SMT against any other type of SMT, any other active or sham intervention, or no treatment control on adult patients with pain in any spinal region. The RCTs must report on continuous pain intensity and/or disability outcomes. Two authors will independently review title and abstract screening, full-text screening, and data extraction. Spinal manipulative therapy techniques will be classified according to the technique application and choice of application sites. We will conduct a network-meta analysis using a frequentist approach and multiple subgroup and sensitivity analyses. DISCUSSION: This will be the most extensive review of thrust SMT to date, and will allow us to estimate the importance of different SMT application procedures used in clinical practice and taught across educational settings. Thus, the results are applicable to clinical practice, educational settings, and research studies. PROSPERO registration: CRD42022375836.
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Osteopatía , Manipulación Espinal , Adulto , Humanos , Metaanálisis en Red , Columna Vertebral , Dolor , Metaanálisis como AsuntoRESUMEN
We apply a new nonparametric Bayesian method for reconstructing the evolution history of the equation of state w of dark energy, based on applying a correlated prior for w(z), to a collection of cosmological data. We combine the latest supernova (SNLS 3 year or Union 2.1), cosmic microwave background, redshift space distortion, and the baryonic acoustic oscillation measurements (including BOSS, WiggleZ, and 6dF) and find that the cosmological constant appears consistent with current data, but that a dynamical dark energy model which evolves from w<-1 at z~0.25 to w>-1 at higher redshift is mildly favored. Estimates of the Bayesian evidence show little preference between the cosmological constant model and the dynamical model for a range of correlated prior choices. Looking towards future data, we find that the best fit models for current data could be well distinguished from the ΛCDM model by observations such as Planck and Euclid-like surveys.
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BACKGROUND: Regadenoson is a coronary vasodilator that causes tachycardia via activation of the sympathetic nervous system. We determined whether ß(1)-adrenergic blockade can attenuate tachycardia without significantly reducing coronary vasodilation induced by regadenoson. METHODS AND RESULTS: Hemodynamics and coronary blood flow (CBF) were measured in conscious dogs. Baseline CBF and heart rate (HR) were 42 ± 2 mL/min and 87 ± 8 bpm (mean ± SEM), respectively. Regadenoson (1, 2.5, and 5 µg/kg) increased peak CBF by 129 ± 10, 149 ± 7, and 174 ± 10 mL/min and HR by 48 ± 6, 67 ± 5, and 85 ± 11 bpm, respectively, (all P < .05 vs baseline). In the presence of metoprolol (1.5 mg/kg), the peak increases in CBF caused by these three doses of regadenoson were reduced by only 11 ± 7%, 10 ± 4%, and 21 ± 2% (P = NS, <.05, and <.05 vs regadenoson alone), respectively, whereas the regadenoson-induced tachycardia was significantly reduced by 55 ± 8%, 55 ± 4%, and 52 ± 5% (all P < .05). In the presence of metoprolol, the duration of the regadenoson-induced increase in CBF was reduced, but the duration of the 2-fold increase in CBF caused by 5 µg/kg regadenoson was still nearly 6 minutes. CONCLUSION: ß(1)-Adrenergic blockade with metoprolol attenuated the regadenoson-induced increase in HR more than the increase in CBF.
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Metoprolol/administración & dosificación , Purinas/efectos adversos , Pirazoles/efectos adversos , Taquicardia/inducido químicamente , Taquicardia/prevención & control , Animales , Antiarrítmicos/administración & dosificación , Perros , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Taquicardia/fisiopatología , Resultado del Tratamiento , Vasodilatadores/efectos adversosRESUMEN
In this Letter, we investigate the environmental dependence of dark matter halos in theories which attempt to explain the accelerated expansion of the Universe by modifying general relativity (GR). Using high-resolution N-body simulations in f(R) gravity models which recover GR in dense environments by virtue of the chameleon mechanism, we find a significant difference, which depends on the environment, between the lensing and dynamical masses of dark matter halos. This environmental dependence of the halo properties can be used as a smoking gun to test GR observationally.
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Effects of ranolazine alone and in the presence of phenylephrine (PE) or isoproterenol (ISO) on hemodynamics, coronary blood flow and heart rate (HR) in the absence and presence of hexamethonium (a ganglionic blocker) were studied in conscious dogs. Ranolazine (0.4, 1.2, 3.6, and 6 mg/kg, intravenous) alone caused transient (<1 minute) and reversible hemodynamic changes. PE (0.3-10 µg/kg) caused a dose-dependent increase in blood pressure and decrease in HR. ISO (0.01-0.3 µg/kg) caused a dose-dependent decrease in blood pressure and an increase in HR. Ranolazine at high (11-13 mM), but not at moderate (4-5 mM) concentrations partially attenuated changes in mean arterial blood pressure and HR caused by either PE or ISO in normal conscious dogs. However, in dogs treated with hexamethonium (20 mg/kg) to cause autonomic blockade, ranolazine (both 4-5 and 11-13 µM) significantly attenuated both the PE- and ISO-induced changes in mean arterial blood pressure. The results suggest that a potential antiadrenergic effect of ranolazine was masked by autonomic control mechanisms in conscious dogs but could be observed when these mechanisms were inhibited (eg, in the hexamethonium-treated dog). Ranolazine, at plasma concentrations <10 µM and in conscious dogs with intact autonomic regulation, had minimal antiadrenergic (α and ß) effects.
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Acetanilidas/uso terapéutico , Antagonistas Adrenérgicos/uso terapéutico , Hemodinámica/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Hipotensión/tratamiento farmacológico , Piperazinas/uso terapéutico , Receptores Adrenérgicos alfa/metabolismo , Receptores Adrenérgicos beta/metabolismo , Acetanilidas/administración & dosificación , Acetanilidas/sangre , Acetanilidas/metabolismo , Antagonistas Adrenérgicos/administración & dosificación , Antagonistas Adrenérgicos/sangre , Antagonistas Adrenérgicos/metabolismo , Animales , Fármacos del Sistema Nervioso Autónomo/administración & dosificación , Fármacos del Sistema Nervioso Autónomo/uso terapéutico , Circulación Coronaria/efectos de los fármacos , Perros , Relación Dosis-Respuesta a Droga , Bloqueadores Ganglionares/farmacología , Cobayas , Frecuencia Cardíaca/efectos de los fármacos , Hexametonio/farmacología , Hipertensión/inducido químicamente , Hipotensión/inducido químicamente , Isoproterenol/administración & dosificación , Isoproterenol/toxicidad , Cinética , Fenilefrina/administración & dosificación , Fenilefrina/toxicidad , Piperazinas/administración & dosificación , Piperazinas/sangre , Piperazinas/metabolismo , Ranolazina , Ratas , Receptores Adrenérgicos alfa/química , Receptores Adrenérgicos beta/química , Vasoconstrictores/administración & dosificación , Vasoconstrictores/toxicidad , Vasodilatadores/administración & dosificación , Vasodilatadores/toxicidadRESUMEN
Oxidative stress is considered to be one of main pathophysiological mechanisms in myocardial ischemia/reperfusion (I/R) injury. Lycium barbarum polysaccharides (LBP), the main ingredient of Lycium barbarum, have potential antioxidant activity. We aimed to investigate the effects of LBP on myocardial I/R injury and explore the underlying mechanisms. Myocardial I/R group was treated with or without LBP to evaluate oxidative stress markers and the role of Nrf2 signal pathway. Our results showed that I/R increased infarct size and the activities of creatine kinase (CK) and lactate dehydrogenase (LDH) when compared with control group. Meanwhile, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were enhanced and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) were decreased. These changes were associated with a significant increase in myocardial apoptosis, ultimately leading to cardiac dysfunction. LBP reduced infarct size (38.4 ± 2 % versus 19.4 ± 1.8 %, p < 0.05), CK and LDH activities and myocardial apoptotic index. Meanwhile, LBP suppressed the production of ROS and restored redox status. Additionally, LBP increased protein level of nuclear Nrf2 in vivo (2.1 ± 0.3 versus 3.8 ± 0.4, p < 0.05) and in vitro (1.9 ± 0.2 versus 3.8 ± 0.1, p < 0.05) and subsequently upregulated heme oxygenase 1 and NADPH dehydrogenase quinone 1 compared to I/R group. Interestingly, Nrf2 siRNA abolished the protective effects of LBP. LBP suppressed oxidative stress damage and attenuated cardiac dysfunction induced by I/R via activation of the Nrf2 antioxidant signal pathway.
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Future weak lensing surveys will map the evolution of matter perturbations and gravitational potentials, yielding a new test of general relativity on cosmic scales. They will probe the relations between matter overdensities, local curvature, and the Newtonian potential. These relations can be modified in alternative gravity theories or by the effects of massive neutrinos or exotic dark energy fluids. We introduce two functions of time and scale which account for any such modifications in the linear regime. We use a principal component analysis to find the eigenmodes of these functions that cosmological data will constrain. The number of constrained modes gives a model-independent forecast of how many parameters describing deviations from general relativity could be constrained, along with w(z). The modes' scale and time dependence tell us which theoretical models will be better tested.
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The conventional analytical HPLC was successfully developed for micro-column separation by using a simple eluate splitting system, a self-preparation of monolithic column and an on-capillary column detector in our laboratory. A typical polystyrene-based monolith was quickly prepared inside the fused-silica capillary, which in situ polymerization was carried out in 10 min by microwave irradiation. The reactant solution consisted of styrene (ST) as a functional monomer, divinylbenzene (DVB) as a cross-linking agent, toluene and isooctane as porogenic solvents, and azobisisobutyronitrile (AIBN) as an initiator. The monolith was proved to form in the center of the capillary and adhered to the column inner wall by the scanning electron micrograph. Its chromatographic behaviors were evaluated in detail by varying the flow rate and percentage of mobile phases, and under the optimal condition, baseline separation of the model analytes including thiourea, benzene, toluene, ethylbenzene was obtained with a highest theoretical plate number near 11,290 N/m by the developed capillary HPLC. Furthermore, the stability and porosity of the prepared monolith were systematically investigated by a simple flow method.