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Find video protocols related to scientific articles indexed in Pubmed.
Effect of single nucleotide polymorphism in thrombin-activatable fibrinolysis inhibitor on the risk of diabetic macrovascular disease.
Blood Coagul. Fibrinolysis
PUBLISHED: 11-15-2014
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Hypofibrinolysis is commonly found in patients with diabetes mellitus and is associated with the increased risk for many diabetic complications. An important inhibitor of fibrinolysis, thrombin-activatable fibrinolysis inhibitor (TAFI), participates in hypofibrinolysis in diabetes mellitus and may be involved in diabetic macrovascular disease. The present study was designed to determine whether TAFI polymorphisms (505G/A and 1040C/T) and TAFI levels are correlated with the development of type 2 diabetes mellitus (T2DM) and macrovascular diseases (MVDs). A total of 249 clinical samples were collected, including 102 healthy individuals (H group), 44 T2DM patients without MVD (T group) and 103 T2DM patients with MVD (M group). The 505G/A polymorphism was equally represented in the three groups. In contrast, analysis of the 1040C/T polymorphism revealed a statistically lower percentage of the T allele in the M group than in the H group (P?=?0.014). This difference was due to decreased T/T homozygotes in the M groups compared with the H group (P?=?0.029). The antigen TAFI level was 31.72?±?13.64% in the H group, 62.56?±?18.77% in the T group (P?
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Reduction-sensitive dual functional nanomicelles for improved delivery of paclitaxel.
Bioconjug. Chem.
PUBLISHED: 08-14-2014
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We have developed a dual-functional nanocarrier composed of a hydrophilic polyethylene glycol (PEG) and a hydrophobic farnesylthiosalicylate (FTS, a nontoxic Ras antagonist), which is effective in delivery of hydrophobic anticancer drug, paclitaxel (PTX). To facilitate the retention of the therapeutic activity of the carrier, FTS was coupled to PEG via a reduction-sensitive disulfide linkage (PEG5k-S-S-FTS2). PEG5k-S-S-FTS2 conjugate formed uniform micelles with very small size (?30 nm) and the hydrophobic drug PTX could be readily incorporated into the micelles. Interestingly, inclusion of a disulfide linkage into the PEG5k-FTS2 micellar system resulted in a 4-fold decrease in the critical micelle concentration (CMC). In addition, the PTX loading capacity and colloidal stability of PTX-loaded micelles were improved. HPLC-MS showed that parent FTS could be more effectively released from PEG5k-S-S-FTS2 conjugate in tumor cells/tissues compared to PEG5k-FTS2 conjugate in vitro and in vivo. PEG5k-S-S-FTS2 exhibited a higher level of cytotoxicity toward tumor cells than PEG5k-FTS2 without a disulfide linkage. Furthermore, PTX-loaded PEG5k-S-S-FTS2 micelles were more effective in inhibiting the proliferation of cultured tumor cells compared to Taxol and PTX loaded in PEG5k-FTS2 micelles. More importantly, PTX-loaded PEG5k-S-S-FTS2 micelles demonstrated superior antitumor activity compared to Taxol and PTX formulated in PEG5k-FTS2 micelles in an aggressive murine breast cancer model (4T1.2).
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MiR-7b directly targets DC-STAMP causing suppression of NFATc1 and c-Fos signaling during osteoclast fusion and differentiation.
Biochim. Biophys. Acta
PUBLISHED: 08-11-2014
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DC-STAMP is a key regulating molecule of osteoclastogenesis and osteoclast precursor (OCP) fusion. Emerging lines of evidence showed that microRNAs play crucial roles in bone metabolism and osteoclast differentiation, but no microRNA has yet been reported to be directly related to OCPs fusion. Through a microarray, we found that the expression of miR-7b in RAW264.7 cells was significantly decreased after induction with M-CSF and RANKL. The overexpression of miR-7b in RAW264.7 cells attenuated the number of TRAP-positive cells number and the formation of multinucleated cells, whereas the inhibition of miR-7b enhanced osteoclastogenesis. Through a dual luciferase reporter assay, we confirmed that miR-7b directly targets DC-STAMP. Other fusogenic molecules, such as CD47, ATP6v0d2, and OC-STAMP, were detected to be down-regulated in accordance with the inhibition of DC-STAMP. Because DC-STAMP also participates in osteoclast differentiation through the ITAM-ITIM network, multiple osteoclast-specific genes in the ITAM-ITIM network were detected to identify how DC-STAMP is involved in this process. The results showed that molecules associated with the ITAM-ITIM network, such as NFATc1 and OSCAR, which are crucial in osteoclastogenesis, were consistently altered due to DC-STAMP inhibition. These findings suggest that miR-7b inhibits osteoclastogenesis and cell-cell fusion by directly targeting DC-STAMP. In addition, the inhibition of DC-STAMP and its downstream signals changed the expression of other fusogenic genes and key regulating genes, such as Nfatc1, c-fos, Akt, Irf8, Mapk1, and Traf6. In conclusion, our findings indicate that miR-7b may be a potential therapeutic target for the treatment of osteoclast-related bone disorders.
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A four-stage hybrid model for hydrological time series forecasting.
PLoS ONE
PUBLISHED: 08-11-2014
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Hydrological time series forecasting remains a difficult task due to its complicated nonlinear, non-stationary and multi-scale characteristics. To solve this difficulty and improve the prediction accuracy, a novel four-stage hybrid model is proposed for hydrological time series forecasting based on the principle of 'denoising, decomposition and ensemble'. The proposed model has four stages, i.e., denoising, decomposition, components prediction and ensemble. In the denoising stage, the empirical mode decomposition (EMD) method is utilized to reduce the noises in the hydrological time series. Then, an improved method of EMD, the ensemble empirical mode decomposition (EEMD), is applied to decompose the denoised series into a number of intrinsic mode function (IMF) components and one residual component. Next, the radial basis function neural network (RBFNN) is adopted to predict the trend of all of the components obtained in the decomposition stage. In the final ensemble prediction stage, the forecasting results of all of the IMF and residual components obtained in the third stage are combined to generate the final prediction results, using a linear neural network (LNN) model. For illustration and verification, six hydrological cases with different characteristics are used to test the effectiveness of the proposed model. The proposed hybrid model performs better than conventional single models, the hybrid models without denoising or decomposition and the hybrid models based on other methods, such as the wavelet analysis (WA)-based hybrid models. In addition, the denoising and decomposition strategies decrease the complexity of the series and reduce the difficulties of the forecasting. With its effective denoising and accurate decomposition ability, high prediction precision and wide applicability, the new model is very promising for complex time series forecasting. This new forecast model is an extension of nonlinear prediction models.
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[Application research on ultrasonic blood flow velocity measurement].
Zhongguo Yi Liao Qi Xie Za Zhi
PUBLISHED: 05-21-2014
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The detection of blood flow velocity has great significance for blood vessel monitoring and the research of cardiovascular pathogenesis. Blood flow velocity measurement based on ultrasonic is becoming more and more popular in doctors and patients compare to several other techniques in nowadays, as they are non-invasive, cheap and fast. Most of the traditional ultrasonic blood flow velocity measurement methods are based on the Doppler frequency shift, but theses methods have some limitations, such as angle dependence, limited spatial resolution and so on. Therefore, blood flow velocity techniques based on non-Doppler frequency shift also get rapid development in recent years. This article mainly summarizes the techniques of blood flow velocity estimation based on ultrasonic in these two aspects.
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The mutation profile of JAK2 and CALR in Chinese Han patients with Philadelphia chromosome-negative myeloproliferative neoplasms.
J Hematol Oncol
PUBLISHED: 05-01-2014
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Mutations in JAK2, MPL and CALR are highly relevant to the Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs). We performed high resolution melting analysis and Sanger sequencing together with T-A cloning to elucidate the unique mutation profile of these genes, in Chinese patients with MPNs. Peripheral blood DNA samples were obtained from 80 patients with polycythemia vera (PV), 80 patients with essential thrombocytosis (ET) and 50 patients with primary myelofibrosis (PMF). Ten PV patients were identified with diverse JAK2 exon 12 mutations. Five novel JAK2 Exon 12 mutation patterns (M532V/E543G, N533D, M535I/H538Y/K549I, E543G and D544N) were described. JAK2 V617F was detected in 140 samples (66 PV, 45 ET and 29 PMF). JAK2 Exon 12 mutations were prevalent (13%) and variable in the Chinese patients. Compared with PV patients with JAK2 V617F mutations, PV patients with JAK2 exon 12 mutations had an earlier median onset of disease (P?=?0.0013). MPL W515L/K mutations were discerned in 4 ET and 3 PMF patients. Two kinds of CALR mutation, c. 1179_1230del and c. 1234_1235insTTGTC were detected in 20 ET and 16 PMF patients. A novel CALR mutation pattern (c. 1173_1223del/c. 1179_1230del) was identified in 2 PMF samples. In addition, 17 scattered point mutations in CALR c.1153 to c.1255 were also detected in 13 cases with CALR frame-shifting variations and 2 cases without CALR frame-shifting variations. Female patients showed a predisposition to CALR mutations (P?=?0.0035). Chinese Ph-negative MPN patients have a unique mutation landscape in the common molecular markers of MPN diagnosis. Validation of the molecular diagnostic pipeline should be emphasized since there is a considerable ethnical diversity in the molecular profiles of Ph-negative MPNs.
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ZEB1 sensitizes lung adenocarcinoma to metastasis suppression by PI3K antagonism.
J. Clin. Invest.
PUBLISHED: 04-24-2014
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Epithelial tumor cells that have undergone epithelial-to-mesenchymal transition (EMT) are typically prone to metastasis and drug resistance and contribute to a poor clinical outcome. The transcription factor ZEB1 is a known driver of EMT, and mediators of ZEB1 represent potential therapeutic targets for metastasis suppression. Here, we have shown that phosphatidylinositol 3-kinase-targeted (PI3K-targeted) therapy suppresses metastasis in a mouse model of Kras/Tp53-mutant lung adenocarcinoma that develops metastatic disease due to high expression of ZEB1. In lung adenocarcinoma cells from Kras/Tp53-mutant animals and human lung cancer cell lines, ZEB1 activated PI3K by derepressing miR-200 targets, including amphiregulin (AREG), betacellulin (BTC), and the transcription factor GATA6, which stimulated an EGFR/ERBB2 autocrine loop. Additionally, ZEB1-dependent derepression of the miR-200 and miR-183 target friend of GATA 2 (FOG2) enhanced GATA3-induced expression of the p110? catalytic subunit of PI3K. Knockdown of FOG2, p110?, and RHEB ameliorated invasive and metastatic propensities of tumor cells. Surprisingly, FOG2 was not required for mesenchymal differentiation, suggesting that mesenchymal differentiation and invasion are distinct and separable processes. Together, these results indicate that ZEB1 sensitizes lung adenocarcinoma cells to metastasis suppression by PI3K-targeted therapy and suggest that treatments to selectively modify the metastatic behavior of mesenchymal tumor cells are feasible and may be of clinical value.
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A novel microfluidic chip electrophoresis strategy for simultaneous, label-free, multi-protein detection based on a graphene energy transfer biosensor.
Analyst
PUBLISHED: 04-24-2014
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A new type of high-throughput and parallel optical sensing platform with a single-color probe based on microfluidic chip electrophoresis combined with aptamer-carboxyfluorescein/graphene oxide energy transfer is reported here. Label-free protein multi-targets were detected, even in challenging complex samples without any pre-treatment.
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[Validation on the elimination of neonatal tetanus programs through Lot Quality Assurance-Cluster Sample Survey in China].
Zhonghua Liu Xing Bing Xue Za Zhi
PUBLISHED: 04-18-2014
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Field surveys were performed under WHO recommended validation procedures, using the Lot Quality Assurance-Cluster Sample(LQA-CS)method to validate the elimination status regarding neonatal tetanus in China.
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Assessment of BAK1 activity in different plant receptor-like kinase complexes by quantitative profiling of phosphorylation patterns.
J Proteomics
PUBLISHED: 03-29-2014
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Plant receptor-like kinases (RLKs) constitute a large family of receptors coordinating developmental programs with adaptation to environmental stresses including immune defenses. BRI1-ASSOCIATED KINASE 1 (BAK1), a member of the plant RLK family, forms receptor complexes with multiple RLK proteins including BRI1, FLS2, EFR and BIK1 to regulate responses to growth hormones or PAMPs. RLK activation and signal initiation involve protein complex formation and phosphorylation/dephosphorylation between BAK1 and its interacting partners. To gain new insight into how phosphorylation contributes to BAK1-mediated signaling specificity, we first mapped the phosphorylation patterns of BAK1 associated with different RLK partners (BRI1, FLS2, EFR and BIK1). Quantitative phospho-pattern profiling by label-free mass spectrometry revealed that differential phosphorylation patterns of RLK partners resulted from altered BAK1 phosphorylation status. More interestingly, the study of two BAK1 mutants (T450A and C408Y) both showing severe defect in immune defense yet normal growth phenotype suggested that varied phosphorylation patterns of RLK partners by BAK1 could be the molecular basis for selective regulation of multiple BAK1-dependent pathways. Taken together, this phospho-pattern profiling strategy allowed for explicit assessment of BAK1 kinase activity in different RLK complexes, which would facilitate elucidation of BAK1 diverse functions in plant development, defense, and adaptation.
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Bedaquiline metabolism: enzymes and novel metabolites.
Drug Metab. Dispos.
PUBLISHED: 02-10-2014
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Bedaquiline is a recently approved drug for the treatment of multidrug-resistant tuberculosis. Adverse cardiac and hepatic drug reactions to bedaquiline have been noted in clinical practice. The current study investigated bedaquiline metabolism in human hepatocytes using a metabolomic approach. Bedaquiline N-demethylation via CYP3A4 was confirmed as the major pathway in bedaquiline metabolism. In addition to CYP3A4, we found that both CYP2C8 and CYP2C19 contributed to bedaquiline N-demethylation. The Km values of CYP2C8, CYP2C19, and CYP3A4 in bedaquiline N-demethylation were 13.1, 21.3, and 8.5 µM, respectively. We also identified a novel metabolic pathway of bedaquiline that produced an aldehyde intermediate. In summary, this study extended our knowledge of bedaquiline metabolism, which can be applied to predict and prevent drug-drug interactions and adverse drug reactions associated with bedaquiline.
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Engineering chiral porous metal-organic frameworks for enantioselective adsorption and separation.
Nat Commun
PUBLISHED: 02-06-2014
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The separation of racemic molecules is of substantial significance not only for basic science but also for technical applications, such as fine chemicals and drug development. Here we report two isostructural chiral metal-organic frameworks decorated with chiral dihydroxy or -methoxy auxiliares from enantiopure tetracarboxylate-bridging ligands of 1,1'-biphenol and a manganese carboxylate chain. The framework bearing dihydroxy groups functions as a solid-state host capable of adsorbing and separating mixtures of a range of chiral aromatic and aliphatic amines, with high enantioselectivity. The host material can be readily recycled and reused without any apparent loss of performance. The utility of the present adsorption separation is demonstrated in the large-scale resolution of racemic 1-phenylethylamine. Control experiments and molecular simulations suggest that the chiral recognition and separation are attributed to the different orientations and specific binding energies of the enantiomers in the microenvironment of the framework.
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Property-based design: optimization and characterization of polyvinyl alcohol (PVA) hydrogel and PVA-matrix composite for artificial cornea.
J Mater Sci Mater Med
PUBLISHED: 01-25-2014
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Each approach for artificial cornea design is toward the same goal: to develop a material that best mimics the important properties of natural cornea. Accordingly, the selection and optimization of corneal substitute should be based on their physicochemical properties. In this study, three types of polyvinyl alcohol (PVA) hydrogels with different polymerization degree (PVA1799, PVA2499 and PVA2699) were prepared by freeze-thawing techniques. After characterization in terms of transparency, water content, water contact angle, mechanical property, root-mean-square roughness and protein adsorption behavior, the optimized PVA2499 hydrogel with similar properties of natural cornea was selected as a matrix material for artificial cornea. Based on this, a biomimetic artificial cornea was fabricated with core-and-skirt structure: a transparent PVA hydrogel core, surrounding by a ringed PVA-matrix composite skirt that composed of graphite, Fe-doped nano hydroxyapatite (n-Fe-HA) and PVA hydrogel. Different ratio of graphite/n-Fe-HA can tune the skirt color from dark brown to light brown, which well simulates the iris color of Oriental eyes. Moreover, morphologic and mechanical examination showed that an integrated core-and-skirt artificial cornea was formed from an interpenetrating polymer network, no phase separation appeared on the interface between the core and the skirt.
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Induction of D-xylose uptake and expression of NAD(P)H-linked xylose reductase and NADP?+?-linked xylitol dehydrogenase in the oleaginous microalga Chlorella sorokiniana.
Biotechnol Biofuels
PUBLISHED: 01-01-2014
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The heterotrophic and mixotrophic culture of oleaginous microalgae is a promising process to produce biofuel feedstock due to the advantage of fast growth. Various organic carbons have been explored for this application. However, despite being one of the most abundant and economical sugar resources in nature, D-xylose has never been demonstrated as a carbon source for wild-type microalgae. The purpose of the present work was to identify the feasibility of D-xylose utilization by the oleaginous microalga Chlorella sorokiniana.
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Are there any different effects of Bifidobacterium, Lactobacillus and Streptococcus on intestinal sensation, barrier function and intestinal immunity in PI-IBS mouse model?
PLoS ONE
PUBLISHED: 01-01-2014
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Research has increasingly suggested that gut flora plays an important role in the development of post-infectious irritable bowel syndrome (PI-IBS). Studies of the curative effect of probiotics for IBS have usually been positive but not always. However, the differences of treatment effects and mechanisms among probiotic stains, or mixture of them, are not clear. In this study, we compared the effects of different probiotics (Befidobacterium, Lactobacillus, Streptococcus or mixture of the three) on intestinal sensation, barrier function and intestinal immunity in PI-IBS mouse model.
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Insulin-Regulated Protein Palmitoylation Impacts Endothelial Cell Function.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 12-19-2013
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Defects in insulin signaling are associated with abnormal endothelial cell function, which occurs commonly in cardiovascular disease. Targets of insulin signaling in endothelial cells are incompletely understood. Protein S-palmitoylation, the reversible modification of proteins by the lipid palmitate, is a post-translational process relevant to cell signaling, but little is known about the role of insulin in protein palmitoylation.
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Jumonji C Domain Protein JMJ705-Mediated Removal of Histone H3 Lysine 27 Trimethylation Is Involved in Defense-Related Gene Activation in Rice.
Plant Cell
PUBLISHED: 11-26-2013
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Histone methylation is an important epigenetic modification in chromatin function, genome activity, and gene regulation. Dimethylated or trimethylated histone H3 lysine 27 (H3K27me2/3) marks silent or repressed genes involved in developmental processes and stress responses in plants. However, the role and the mechanism of the dynamic removal of H3K27me2/3 during gene activation remain unclear. Here, we show that the rice (Oryza sativa) Jumonji C (jmjC) protein gene JMJ705 encodes a histone lysine demethylase that specifically reverses H3K27me2/3. The expression of JMJ705 is induced by stress signals and during pathogen infection. Overexpression of the gene reduces the resting level of H3K27me2/3 resulting in preferential activation of H3K27me3-marked biotic stress-responsive genes and enhances rice resistance to the bacterial blight disease pathogen Xanthomonas oryzae pathovar oryzae. Mutation of the gene reduces plant resistance to the pathogen. Further analysis revealed that JMJ705 is involved in methyl jasmonate-induced dynamic removal of H3K27me3 and gene activation. The results suggest that JMJ705 is a biotic stress-responsive H3K27me2/3 demethylase that may remove H3K27me3 from marked defense-related genes and increase their basal and induced expression during pathogen infection.
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Biomimetic spiral-cylindrical scaffold based on hybrid chitosan/cellulose/nano-hydroxyapatite membrane for bone regeneration.
ACS Appl Mater Interfaces
PUBLISHED: 11-18-2013
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Natural bone is a complex material with well-designed architecture. To achieve successful bone integration and regeneration, the constituent and structure of bone-repairing scaffolds need to be functionalized synergistically based on biomimetics. In this study, a hybrid membrane composed of chitosan (CS), sodium carboxymethyl cellulose (CMC), and nano-hydroxyapatite (n-HA) was curled in a concentric manner to generate an anisotropic spiral-cylindrical scaffold, with compositional and structural properties mimicking natural bone. After optimization in terms of morphology, hydrophilicity, swelling and degradation pattern, the osteoblast cells seeded on the membrane of 60 wt% n-HA exhibited the highest cell viability and osteocalcin expression. In vivo osteogenesis assessment revealed that the spiral-cylindrical architecture played a dominant role in bone regeneration and osseointegration. Newly formed bone tissue grew through the longitudinal direction of the cylinder-shaped scaffold bridging both ends of the defect, bone marrow penetrated the entire scaffold and formed a medullary cavity in the center of the spiral cylinder. This study for the first time demonstrates that the spiral-cylindrical scaffold can promote complete infiltration of bone tissues in vivo, leading to successful osteointegration and functional reconstruction of bone defects. It suggests that the biomimetic spiral-cylindrical scaffold could be a promising candidate for bone regeneration applications.
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CPY3A4-Mediated ?-Hydroxyaldehyde Formation in Saquinavir Metabolism.
Drug Metab. Dispos.
PUBLISHED: 11-08-2013
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Saquinavir (SQV) is a protease inhibitor widely used for the treatment of human immunodeficiency virus (HIV) infection. We profiled SQV metabolism in mice using a metabolomic approach. Thirty SQV metabolites were identified in mouse feces and urine, of which 20 are novel. Most metabolites observed in mice were recapitulated in human liver microsomes. Among these novel metabolites, one ?-hydroxyaldehyde produced from SQV N-dealkylation was noted and verified for the first time. Meanwhile, the corresponding product (3S)-N-tert-butyldecahydro-isoquinoline-3-carboxamide and its further metabolites were identified in mouse urine. The ?-hydroxyaldehyde pathway was confirmed by using semicarbazide as a trapping reagent as well. Using recombinant cytochrome P450 (CYP450) isoenzymes and Cyp3a-null mice, CYP3A was identified as the dominant enzyme contributing to the formation of ?-hydroxyaldehyde. This study enhances our knowledge of SQV metabolism, which can be used for predicting drug-drug interactions and further understanding the mechanism of adverse effects associated with SQV.
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Role of CYP3A in isoniazid metabolism in vivo.
Drug Metab. Pharmacokinet.
PUBLISHED: 10-29-2013
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  Isoniazid (INH), a first-line drug for tuberculosis control, frequently causes liver injury. Multiple previous reports suggest that CYP3A is involved in INH metabolism, bioactivation and hepatotoxicity, although direct evidence is unavailable. In the current study, wild-type and Cyp3a-null mice were used to determine the potential role of Cyp3a in INH metabolism in vivo. Compared to wild-type mice, there were no significant differences in the pharmacokinetic profiles of INH and acetyl-isoniazid in Cyp3a-null mice after an oral administration of 50 mg/kg INH. With the same treatment, distribution of INH and its major metabolites was similar in the liver of wild-type and Cyp3a-null mice. A reactive metabolite of INH was trapped by N-?-acetyl-L-lysine in mouse liver microsomes, but Cyp3a does not contribute to this bioactivation pathway. In addition, no liver injury was observed in wild-type and Cyp3a-null mice treated with 60 or 120 mg/kg INH. In summary, Cyp3a has no effect on systemic pharmacokinetics of INH in mice. Further studies are needed to determine whether and how exactly CYP3A is involved in INH bioactivation and hepatotoxicity.
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A carbohydrate-based approach for the total synthesis of (-)-dinemasone B, (+)-4a-epi-dinemasone B, (-)-7-epi-dinemasone B, and (+)-4a,7-Di-epi-dinemasone B.
J. Org. Chem.
PUBLISHED: 09-11-2013
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(-)-Dinemasone B was isolated by Krohn and co-workers from a culture of the endophytic fungus Dinemasporium strigosum and has shown promising antimicrobial activity. Described herein is the first total synthesis of (-)-dinemasone B, (+)-4a-epi-dinemasone B, (-)-7-epi-dinemasone B, and (+)-4a,7-di-epi-dinemasone B. Their absolute configurations were also determined. The developed synthesis features a stereoselective reduction of C-glycosidic ketone, lactonization, and E-olefination of aldehyde starting from D-glucose.
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Location and contribution of individual ?-glucosidase from Neurospora crassa to total ?-glucosidase activity.
Arch. Microbiol.
PUBLISHED: 07-04-2013
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This study investigated the cellular location and the contribution of individual ?-glucosidase (BGL) to total BGL activity in Neurospora crassa. Among the seven bgl genes, bgl3, bgl5, and bgl7 were transcribed at basal levels, whereas bgl1, bgl2, bgl4, and bgl6 were significantly up-regulated when the wild-type strain was induced with cellulose (Avicel). BGL1 and BGL4 were found to be contributors to intracellular BGL activity, whereas the activities of BGL2 and BGL6 were mainly extracellular. Sextuple bgl deletion strains expressing one of the three basally transcribed bgls did not produce any detectable BGL activity when they were grown on Avicel. BGL6 is the major contributor to overall BGL activity, and most of its activity resides cell-bound. The sextuple bgl deletion strain containing only bgl6 utilized cellobiose at a rate similar to that of the wild type, while the strain with only bgl6 deleted utilized cellobiose much slower than that of the wild type.
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Identification and functional analysis of phosphorylation residues of the Arabidopsis BOTRYTIS-INDUCED KINASE1.
Protein Cell
PUBLISHED: 07-01-2013
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Arabidopsis BOTRYTIS-INDUCED KINASE1 (BIK1) is a receptor-like cytoplasmic kinase acting early in multiple signaling pathways important for plant growth and innate immunity. It is known to form a signaling complex with a cell-surface receptor FLS2 and a co-receptor kinase BAK1 to transduce signals upon perception of pathogen-associated molecular patterns (PAMPs). Although site-specific phosphorylation is speculated to mediate the activation and function of BIK1, few studies have been devoted to complete profiling of BIK1 phosphorylation residues. Here, we identified nineteen in vitro autophosphorylation sites of BIK1 including three phosphotyrosine sites, thereby proving BIK1 is a dual-specificity kinase for the first time. The kinase activity of BIK1 substitution mutants were explicitly assessed using quantitative mass spectrometry (MS). Thr-237, Thr-242 and Tyr-250 were found to most significantly affect BIK1 activity in autophosphorylation and phosphorylation of BAK1 in vitro. A structural model of BIK1 was built to further illustrate the molecular functions of specific phosphorylation residues. We also mapped new sites of FLS2 phosphorylation by BIK1, which are different from those by BAK1. These in vitro results could provide new hypotheses for more in-depth in vivo studies leading to deeper understanding of how phosphorylation contributes to BIK1 activation and mediates downstream signaling specificity.
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Role of bile acids in liver injury and regeneration following acetaminophen overdose.
Am. J. Pathol.
PUBLISHED: 06-24-2013
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Bile acids play a critical role in liver injury and regeneration, but their role in acetaminophen (APAP)-induced liver injury is not known. We tested the effect of bile acid modulation on APAP hepatotoxicity using C57BL/6 mice, which were fed a normal diet, a 2% cholestyramine (CSA)-containing diet for bile acid depletion, or a 0.2% cholic acid (CA)-containing diet for 1 week before treatment with 400 mg/kg APAP. CSA-mediated bile acid depletion resulted in significantly higher liver injury and delayed regeneration after APAP treatment. In contrast, 0.2% CA supplementation in the diet resulted in a moderate delay in progression of liver injury and significantly higher liver regeneration after APAP treatment. Either CSA-mediated bile acid depletion or CA supplementation did not affect hepatic CYP2E1 levels or glutathione depletion after APAP treatment. CSA-fed mice exhibited significantly higher activation of c-Jun N-terminal protein kinases and a significant decrease in intestinal fibroblast growth factor 15 mRNA after APAP treatment. In contrast, mice fed a 0.2% CA diet had significantly lower c-Jun N-terminal protein kinase activation and 12-fold higher fibroblast growth factor 15 mRNA in the intestines. Liver regeneration after APAP treatment was significantly faster in CA diet-fed mice after APAP administration secondary to rapid cyclin D1 induction. Taken together, these data indicate that bile acids play a critical role in both initiation and recovery of APAP-induced liver injury.
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Circulating acylcarnitines as biomarkers of mitochondrial dysfunction after acetaminophen overdose in mice and humans.
Arch. Toxicol.
PUBLISHED: 06-22-2013
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Acetaminophen (APAP) is a widely used analgesic. However, APAP overdose is hepatotoxic and is the primary cause of acute liver failure in the developed world. The mechanism of APAP-induced liver injury begins with protein binding and involves mitochondrial dysfunction and oxidative stress. Recent efforts to discover blood biomarkers of mitochondrial damage have identified increased plasma glutamate dehydrogenase activity and mitochondrial DNA concentration in APAP overdose patients. However, a problem with these markers is that they are too large to be released from cells without cell death or loss of membrane integrity. Metabolomic studies are more likely to reveal biomarkers that are useful at early time points, before injury begins. Similar to earlier work, our metabolomic studies revealed that acylcarnitines are elevated in serum from mice after treatment with toxic doses of APAP. Importantly, a comparison with furosemide demonstrated that increased serum acylcarnitines are specific for mitochondrial dysfunction. However, when we measured these compounds in plasma from humans with liver injury after APAP overdose, we could not detect any significant differences from control groups. Further experiments with mice showed that N-acetylcysteine, the antidote for APAP overdose in humans, can reduce acylcarnitine levels in serum. Altogether, our data do not support the clinical measurement of acylcarnitines in blood after APAP overdose due to the standard N-acetylcysteine treatment in patients, but strongly suggest that acylcarnitines would be useful mechanistic biomarkers in other forms of liver injury involving mitochondrial dysfunction.
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Circadian gene Clock contributes to cell proliferation and migration of glioma and is directly regulated by tumor-suppressive miR-124.
FEBS Lett.
PUBLISHED: 04-28-2013
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Although the roles of circadian Clock genes and microRNAs in tumorigenesis have been profoundly studied, mechanisms of cross-talk between them in regulation of gliomagenesis are poorly understood. Here we show that the expression level of CLOCK is significantly increased in high-grade human glioma tissues and glioblastoma cell lines. In contrast miR-124 is attenuated in similar samples. Further studies show that Clock is a direct target of miR-124, and either restoration of miR-124 or silencing of CLOCK can reduce the activation of NF-?B. In conclusion, we suggest that as a target of glioma suppressor miR-124, CLOCK positively regulates glioma proliferation and migration by reinforcing NF-?B activity.
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Cerenkov luminescence tomography of aminopeptidase N (APN/CD13) expression in mice bearing HT1080 tumors.
Mol Imaging
PUBLISHED: 03-16-2013
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In vivo imaging of aminopeptidase N (APN/CD13) expression is crucial for the early detection of cancer. This study attempted to show that APN/CD13 expression can be imaged and quantified with novel Cerenkov luminescence tomography (CLT). Na131I with various activities was placed at different depths in a tissue-mimicking phantom, and various porcine tissues and luminescent images were acquired. The binding of 131I-NGR with human fibrosarcoma HT1080 and human colon cancer HT-29 cells was detected with Cerenkov luminescence imaging (CLI). Nude mice bearing HT-1080 tumors were imaged after injection with 131I-NGR using both planar and tomographic CLI methods. The penetration depth increased with ascending activity of Na131I. There was a robust linear correlation between the optical signal intensity and the HT1080 cell numbers (r2 = .9691), as well as the activity (r2 = .9860). The three-dimensional visualization CLT results clearly showed that 131I-NGR uptake in tumor tissues represented a high expression of the APN/CD13 receptor. CLT also allowed quantifying 131I-NGR uptake in tumor tissues showing an average activity of 0.1388 ± 4.6788E-6 MBq in tumor tissues. Our study indicated that 131I-NGR combined with CLT allowed us to image and quantify tumor-associated APN/CD13 expression noninvasively. The promising CLT technique could be potentially used for sensitively evaluating tumor angiogenesis in vivo.
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Muscle lipogenesis balances insulin sensitivity and strength through calcium signaling.
J. Clin. Invest.
PUBLISHED: 02-08-2013
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Exogenous dietary fat can induce obesity and promote diabetes, but endogenous fat production is not thought to affect skeletal muscle insulin resistance, an antecedent of metabolic disease. Unexpectedly, the lipogenic enzyme fatty acid synthase (FAS) was increased in the skeletal muscle of mice with diet-induced obesity and insulin resistance. Skeletal muscle-specific inactivation of FAS protected mice from insulin resistance without altering adiposity, specific inflammatory mediators of insulin signaling, or skeletal muscle levels of diacylglycerol or ceramide. Increased insulin sensitivity despite high-fat feeding was driven by activation of AMPK without affecting AMP content or the AMP/ATP ratio in resting skeletal muscle. AMPK was induced by elevated cytosolic calcium caused by impaired sarco/endoplasmic reticulum calcium ATPase (SERCA) activity due to altered phospholipid composition of the sarcoplasmic reticulum (SR), but came at the expense of decreased muscle strength. Thus, inhibition of skeletal muscle FAS prevents obesity-associated diabetes in mice, but also causes muscle weakness, which suggests that mammals have retained the capacity for lipogenesis in muscle to preserve physical performance in the setting of disrupted metabolic homeostasis.
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Colorimetric surface plasmon resonance imaging (SPRI) biosensor array based on polarization orientation.
Biosens Bioelectron
PUBLISHED: 02-06-2013
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A colorimetric surface plasmon resonance (SPR) imaging biosensor array based on polarization orientation rotation is presented in this paper. It measures the spectral characteristic variations caused by the steep phase difference between the p- and s-polarization occurring at surface plasmon excitation. It provides one-order of magnitude sensor resolution improvement comparing to existing phase-sensitive SPR imaging sensors and the two-dimensional (2D) sensing capability of the imaging sensor enables multiplex, high throughput array based simultaneous detection for a range of different bio-molecular interactions. Experiments on the binding interactions detection between anti-bovine serum albumin (anti-BSA) and BSA antigen have been performed. All binding interactions occurred at 5×4 protein array were real-time monitored simultaneously. A sensor resolution of 8.26ng/ml (125pM) has been demonstrated, which is one-order of magnitude (12 times) better than the detection limit reported by existing phase-sensitive SPR imaging sensors in the literature, while no time-consuming phase modulation and phase extraction processes are required. Furthermore, the optical colorimetric image read-out of the sensor is easy to be identified by the end users comparing to conventional intensity or phase information. The colorimetric SPR imaging biosensor array can find promising potential applications in high throughput clinical disease diagnosis, protein biomarkers screening and drug screening.
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Molecular Optical Simulation Environment (MOSE): a platform for the simulation of light propagation in turbid media.
PLoS ONE
PUBLISHED: 02-04-2013
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The study of light propagation in turbid media has attracted extensive attention in the field of biomedical optical molecular imaging. In this paper, we present a software platform for the simulation of light propagation in turbid media named the "Molecular Optical Simulation Environment (MOSE)". Based on the gold standard of the Monte Carlo method, MOSE simulates light propagation both in tissues with complicated structures and through free-space. In particular, MOSE synthesizes realistic data for bioluminescence tomography (BLT), fluorescence molecular tomography (FMT), and diffuse optical tomography (DOT). The user-friendly interface and powerful visualization tools facilitate data analysis and system evaluation. As a major measure for resource sharing and reproducible research, MOSE aims to provide freeware for research and educational institutions, which can be downloaded at http://www.mosetm.net.
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Human PXR modulates hepatotoxicity associated with rifampicin and isoniazid co-therapy.
Nat. Med.
PUBLISHED: 01-24-2013
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Co-therapy with rifampicin (RIF) and isoniazid (INH) used to treat tuberculosis in humans frequently causes liver injury. Here, using a pregnane X receptor (PXR)-humanized mouse model, we found that co-treatment with RIF and INH causes accumulation of the endogenous hepatotoxin protoporphyrin IX in the liver through PXR-mediated alteration of the heme biosynthesis pathway. These results provide insight into the mechanism of liver injury induced by co-treatment with these compounds and may lead to their safer use in the clinic.
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Influence investigation of a void region on modeling light propagation in a heterogeneous medium.
Appl Opt
PUBLISHED: 01-23-2013
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A void region exists in some biological tissues, and previous studies have shown that inaccurate images would be obtained if it were not processed. A hybrid radiosity-diffusion method (HRDM) that couples the radiosity theory and the diffusion equation has been proposed to deal with the void problem and has been well demonstrated in two-dimensional and three-dimensional (3D) simple models. However, the extent of the impact of the void region on the accuracy of modeling light propagation has not been investigated. In this paper, we first implemented and verified the HRDM in 3D models, including both the regular geometries and a digital mouse model, and then investigated the influences of the void region on modeling light propagation in a heterogeneous medium. Our investigation results show that the influence of the region can be neglected when the size of the void is less than a certain range, and other cases must be taken into account.
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Nuclear receptors in herb-drug interactions.
Drug Metab. Rev.
PUBLISHED: 01-22-2013
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Widespread usage of herbs as supplements or medicines raises the potential of herb-drug interactions (HDIs). Basically, HDIs occur by pharmacokinetic and/or pharmacodynamic pathways. Nuclear receptors (NRs) are a class of transcription factors whose role in drug interactions has been defined. A large number of herbs activate NRs, resulting in HDIs. NR-mediated HDIs are similar to drug-drug interactions, but are more complicated because of the presence of multiple compounds in herbs. Dosage and therapeutic sequence as well as various other factors, including the patients gender, age, and genetic makeup, may affect outcomes of NR-mediated HDIs.
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Insertion of TAT peptide and perturbation of negatively charged model phospholipid bilayer revealed by neutron diffraction.
Biochim. Biophys. Acta
PUBLISHED: 01-18-2013
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TAT peptide is one of the best-characterized cell penetrating peptides derived from the transactivator of transcription protein from the human immunodeficiency virus 1. The aim of this study was to investigate the interaction between TAT peptide and partially negatively-charged phospholipid bilayer by using lamellar neutron diffraction. The main findings are the existence of a contiguous water channel across the bilayer in the presence of TAT peptide. Taken in combination with other observations, including thinning of the lipid bilayer, this unambiguously locates the peptide within the lipid bilayer. The interaction of TAT peptide with anionic lipid bilayer, composed of an 80:20 mixture of DOPC and DOPS, takes place at two locations. One is in the peripheral aqueous phase between adjacent bilayers and the second is below the glycerol backbone region of bilayer. A membrane thinning above a peptide concentration threshold (1mol%) was found, as was a contiguous transbilayer water channel at the highest peptide concentration (10mol%). This evidence leads to the suggestion that the toroidal pore model might be involved in the transmembrane of TAT peptide. We interpret the surface peptide distribution in the peripheral aqueous phase to be a massive exclusion of TAT peptide from its intrinsic location below the glycerol backbone region of the bilayer, due to the electrostatic attraction between the negatively-charged headgroups of phospholipids and the positively charged TAT peptides. Finally, we propose that the role that negatively-charged headgroups of DOPS lipids play in the transmembrane of TAT peptide is less important than previously thought.
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Direct cellobiose production from cellulose using sextuple beta-glucosidase gene deletion Neurospora crassa mutants.
Enzyme Microb. Technol.
PUBLISHED: 01-07-2013
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Direct cellobiose production from cellulose by a genetically modified fungus-Neurospora crassa, was explored in this study. A library of N. crassa sextuple beta-glucosidase (bgl) gene deletion strains was constructed. Various concentrations of cellobiose were detected in the culture broth of the N. crassa sextuple beta-glucosidase (bgl) gene deletion strains when grown on Avicel without exogenous cellulase addition. The sextuple bgl deletion strains expressing one of the three basally transcribed bgl genes are the best cellobiose producers. For most sextuple strains, the multiple bgl gene deletion has no negative effect on the production of other cellulases. The induction of major endoglucanases and exoglucanases on Avicel in most of the sextuple bgl deletions strains was as fast as or faster than that of the wild type, except for strain F4. The best cellobiose producing strain, F5, produced 7.7 g/L of cellobiose from 20 g/L of Avicel in four days and utilized the Avicel as fast as did the wild type (even in the presence of high cellobiose concentration). The cellobiose yield from cellulose was about 48.3%.
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The rice NAD(+)-dependent histone deacetylase OsSRT1 targets preferentially to stress- and metabolism-related genes and transposable elements.
PLoS ONE
PUBLISHED: 01-01-2013
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Histone acetylation/deacetylation is an important chromatin modification for epigenetic regulation of gene expression. Silent information regulation2 (Sir2)-related sirtuins are nicotinamide-adenine dinucleotide (NAD(+))-dependent histone deacetylases (HDAC). The mammalian sirtuin family comprises 7 members (SIRT1-7) that act in different cellular compartments to regulate metabolism and aging. The rice genome contains only two Sir2-related genes: OsSRT1 (or SRT701) and OsSRT2 (orSRT702). OsSRT1 is closely related to the mammalian SIRT6, while OsSRT2 is homologous to SIRT4. Previous work has shown that OsSRT1 is required for the safeguard against genome instability and cell damage in rice plant. In this work we investigated the role of OsSRT1 on genome-wide acetylation of histone H3 lysine 9 (H3K9ac) and studied the genome-wide binding targets of OsSRT1. The study reveals that OsSRT1 binds to loci with relatively low levels of H3K9ac and directly regulates H3K9ac and expression of many genes that are related to stress and metabolism, indicating that OsSRT1 is an important site-specific histone deacetylase for gene regulation in rice. In addition, OsSRT1 is found to also target to several families of transposable elements, suggesting that OsSRT1 is directly involved in transposable element repression.
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Metabolomic screening and identification of the bioactivation pathways of ritonavir.
Chem. Res. Toxicol.
PUBLISHED: 11-17-2011
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Ritonavir-boosted protease inhibitor regimens are widely used for HIV chemotherapy. However, ritonavir causes multiple side effects, and the mechanisms are not fully understood. The current study was designed to explore the metabolic pathways of ritonavir that may be related to its toxicity. Metabolomic analysis screened out 26 ritonavir metabolites in mice, and half of them are novel. These novel ritonavir metabolites include two glycine conjugated, two N-acetylcysteine conjugated, and three ring-open products. Accompanied with the generation of ritonavir ring-open metabolites, the formation of methanethioamide and 2-methylpropanethioamide were expected. Upon the basis of the structures of these novel metabolites, five bioactivation pathways are proposed, which may be associated with sulfation and epoxidation. By using Cyp3a-null mice, we confirmed that CYP3A is involved in four pathways of RTV bioactivation. In addition, all these five bioactivation pathways were recapitulated in the incubation of ritonavir in human liver microsomes. Further studies are suggested to determine the role of CYP3A and these bioactivation pathways in ritonavir toxicity.
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Pregnane X receptor- and CYP3A4-humanized mouse models and their applications.
Br. J. Pharmacol.
PUBLISHED: 10-28-2011
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Pregnane X receptor (PXR) is a pivotal nuclear receptor modulating xenobiotic metabolism primarily through its regulation of CYP3A4, the most important enzyme involved in drug metabolism in humans. Due to the marked species differences in ligand recognition by PXR, PXR-humanized (hPXR) mice, and mice expressing human PXR and CYP3A4 (Tg3A4/hPXR) were established. hPXR and Tg3A4/hPXR mice are valuable models for investigating the role of PXR in xenobiotic metabolism and toxicity, in lipid, bile acid and steroid hormone homeostasis, and in the control of inflammation.
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A tetrahedron beam computed tomography benchtop system with a multiple pixel field emission x-ray tube.
Med Phys
PUBLISHED: 10-14-2011
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To demonstrate the feasibility of Tetrahedron Beam Computed Tomography (TBCT) using a carbon nanotube (CNT) multiple pixel field emission x-ray (MPFEX) tube.
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CYP3A4-mediated lopinavir bioactivation and its inhibition by ritonavir.
Drug Metab. Dispos.
PUBLISHED: 09-27-2011
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The combination of lopinavir (LPV) and ritonavir (RTV) is one of the preferred regimens for the treatment of HIV infection with confirmed efficacy and relatively low toxicity. LPV alone suffers the poor bioavailability due to its rapid and extensive metabolism. RTV boosts the plasma concentration of LPV by suppressing its metabolism and thus increasing LPV efficacy. In the current study, we found that RTV also inhibits LPV bioactivation. LPV bioactivation was investigated in human liver microsomes and cDNA-expressed human cytochromes P450. Twelve GSH-trapped reactive metabolites of LPV were identified by using a metabolomic approach. Semicarbazide-trapped reactive metabolites of LPV were also detected. RTV effectively suppressed all pathways of LPV bioactivation via CYP3A4 inhibition. Our data together with previous reports suggest that LPV plus RTV is an ideal combination because RTV not only boosts LPV plasma concentration, but it decreases LPV bioactivation.
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Metabolomic analysis reveals novel isoniazid metabolites and hydrazones in human urine.
Drug Metab. Pharmacokinet.
PUBLISHED: 08-16-2011
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Isoniazid (INH) is a first-line drug for tuberculosis control; the side effects of INH are thought to be associated with its metabolism, and this study was designed to globally characterize isoniazid metabolism. Metabolomic strategies were used to profile isoniazid metabolism in humans. Eight known and seven novel INH metabolites and hydrazones were identified in human urine. The novel products included two hydroxylated INH metabolites and five hydrazones. The two novel metabolites were determined as 2-oxo-1,2-dihydro-pyridine-4-carbohydrazide and isoniazid N-oxide. Five novel hydrazones were produced by condensation of isoniazid with keto acids that are intermediates in the metabolism of essential amino acids, namely, leucine and/or isoleucine, lysine, tyrosine, tryptophan, and phenylalanine. This study enhances our knowledge of isoniazid metabolism and disposition and may offer new avenues for investigating INH-induced toxicity.
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CYP2D plays a major role in berberine metabolism in liver of mice and humans.
Xenobiotica
PUBLISHED: 07-25-2011
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Berberine is a widely used plant extract for gastrointestinal infections, and is reported to have potential benefits in treatment for diabetes and hypercholesterolemia. It has been suggested that interactions between berberine-containing products and cytochromes P450 (CYPs) exist, but little is known about which CYPs mediate the metabolism of berberine in vivo. In this study, berberine metabolites in urine and feces of mice were analyzed, and the role that CYPs play in producing these metabolites were characterized in liver microsomes from mice (MLM) and humans (HLM), as well as recombinant human CYPs. Eleven berberine metabolites were identified in mice, including 5 unconjugated metabolites, mainly in feces, and 6 glucuronide and sulfate conjugates, predominantly in urine. Three novel berberine metabolites were observed. Three unconjugated metabolites of berberine were produced by MLM, HLM, and recombinant human CYPs. CYP2D6 was the primary recombinant human CYP producing these metabolites, followed by CYP1A2, 3A4, 2E1 and CYP2C19. The metabolism of berberine in MLM and HLM was decreased the most by a CYP2D inhibitor, and moderately by inhibitors of CYP1A and 3A. CYP2D plays a major role in berberine biotransformation, therefore, CYP2D6 pharmacogenetics and potential drug-drug interactions should be considered when berberine is used.
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Graphics processing unit parallel accelerated solution of the discrete ordinates for photon transport in biological tissues.
Appl Opt
PUBLISHED: 07-21-2011
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As a widely used numerical solution for the radiation transport equation (RTE), the discrete ordinates can predict the propagation of photons through biological tissues more accurately relative to the diffusion equation. The discrete ordinates reduce the RTE to a serial of differential equations that can be solved by source iteration (SI). However, the tremendous time consumption of SI, which is partly caused by the expensive computation of each SI step, limits its applications. In this paper, we present a graphics processing unit (GPU) parallel accelerated SI method for discrete ordinates. Utilizing the calculation independence on the levels of the discrete ordinate equation and spatial element, the proposed method reduces the time cost of each SI step by parallel calculation. The photon reflection at the boundary was calculated based on the results of the last SI step to ensure the calculation independence on the level of the discrete ordinate equation. An element sweeping strategy was proposed to detect the calculation independence on the level of the spatial element. A GPU parallel frame called the compute unified device architecture was employed to carry out the parallel computation. The simulation experiments, which were carried out with a cylindrical phantom and numerical mouse, indicated that the time cost of each SI step can be reduced up to a factor of 228 by the proposed method with a GTX 260 graphics card.
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Gender difference of unconscious attentional bias in high trait anxiety individuals.
PLoS ONE
PUBLISHED: 04-29-2011
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By combining binocular suppression technique and a probe detection paradigm, we investigated attentional bias to invisible stimuli and its gender difference in both high trait anxiety (HTA) and low trait anxiety (LTA) individuals. As an attentional cue, happy or fearful face pictures were presented to HTAs and LTAs for 800 ms either consciously or unconsciously (through binocular suppression). Participants were asked to judge the orientation of a gabor patch following the face pictures. Their performance was used to measure attentional effect induced by the cue. We found gender differences of attentional effect only in the unconscious condition with HTAs. Female HTAs exhibited difficulty in disengaging attention from the location where fearful faces were presented, while male HTAs showed attentional avoidance of it. Our results suggested that the failure to find attentional avoidance of threatening stimuli in many previous studies might be attributed to consciously presented stimuli and data analysis regardless of participants gender. These findings also contributed to our understanding of gender difference in anxiety disorder.
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Lipoexpediency: de novo lipogenesis as a metabolic signal transmitter.
Trends Endocrinol. Metab.
PUBLISHED: 04-27-2011
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De novo lipogenesis, the production of fats from simple precursors, is often dismissed as irrelevant to the pathobiology of obesity caused by positive energy balance due to typical high fat diets. However, emerging data implicate de novo lipogenesis in the generation of metabolic signals that alter disease risk. Exploiting this signaling pathway represents lipoexpediency. Lipoexpediency is the concept of directing fats toward benefit even in the setting of lipid overload, and represents a strategy to complement efforts aimed at improving energy balance. Optimizing lipid signals initiated by key lipogenic enzymes such as fatty acid synthase might limit morbidity in people who are unlikely to abandon the lifestyle of the sedentary gourmand.
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Profiling the reactive metabolites of xenobiotics using metabolomic technologies.
Chem. Res. Toxicol.
PUBLISHED: 04-21-2011
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A predominant pathway of xenobiotic-induced toxicity is initiated by bioactivation. Characterizing reactive intermediates will provide information on the structure of reactive species, thereby defining a potential bioactivation mechanism. Because most reactive metabolites are not stable, it is difficult to detect them directly. Reactive metabolites can form adducts with trapping reagents, such as glutathione, which makes the reactive metabolites detectable. However, it is challenging to "fish" these adducts out from a complex biological matrix, especially for adducts generated via uncommon metabolic pathways. In this regard, we developed a novel approach based upon metabolomic technologies to screen trapped reactive metabolites. The bioactivation of pulegone, acetaminophen, and clozapine were reexamined by using this metabolomic approach. In all these cases, a large number of trapped reactive metabolites were readily identified. These data indicate that this metabolomic approach is an efficient tool to profile xenobiotic bioactivation.
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Effects of household, workplace, and public place smoking restrictions on smoking cessation.
Health Place
PUBLISHED: 04-04-2011
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The aim of this study was to evaluate the association between environmental smoking restrictions, distinguished by site, and smoking cessation by Chinese urban residents. Recruited through multi-stage quota-sampling, residents in six Chinese cities were surveyed. Data were both individual-level and city-level. Among 4735 respondents, 715 were identified as successful quitters and 405 as unsuccessful. Multilevel logistic regression analysis showed smoking cessation to be associated with city-level public place and workplace restrictions and individual-level workplace and household restrictions. Results offer justification for decision-makers to implement environmental tobacco control policies and related public health interventions aimed at markedly diminishing the high smoking prevalence in China.
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Mental health status and related characteristics of Chinese male rural-urban migrant workers.
Community Ment Health J
PUBLISHED: 02-28-2011
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To explore mental health status and related characteristics in a sample of Chinese male rural-urban migrants. Subjects were 1,595 male rural-urban migrant workers selected though a multi-stage sample survey conducted in two cities (Hangzhou and Guangzhou). Data were collected by means of a self-administered questionnaire. Both life and work stressors were examined. Stress and mental health status were measured by the Chinese Perceived Stress Scale (CPSS) and the Chinese Health Questionnaire (CHQ), respectively. Unconditional logistic regression analysis was performed to identify factors associated with probable mental disorders. There are approximately 120 million rural-urban migrants in China. The prevalence of probable mental disorders in the sample population was 24.4% (95% CI: 23.3-25.5%), which was higher than among urban residents (20.2%, 95% CI: 18.8-21.7%). Logistic regression analysis revealed that five characteristics were positively associated with risk for probable mental disorders: originating in the South (OR = 2.00; 95% CI = 1.02, 4.00), higher life stress (OR = 7.63; 95% CI = 5.88, 10.00), staying in the city for 5-9 months each year (OR = 2.56; 95% CI = 1.67, 3.85), higher work stress (OR = 2.56; 95% CI = 1.96, 3.33), and separation from wife (OR = 2.43; 95% CI = 1.61, 3.57). Employment in machinery and transportation (OR = 0.54; 95% CI = 0.36, 0.81) and higher self-worth (OR = 0.42; 95% CI = 0.28, 0.62) were negatively associated. Findings support an urgent need to develop specific policies and programs to address mental health problems among Chinese rural-urban migrants.
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Design and Characteristics of a Multichannel Front-End ASIC Using Current-Mode CSA for Small-Animal PET Imaging.
IEEE Trans Biomed Circuits Syst
PUBLISHED: 02-01-2011
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This paper presents the design and characteristics of a front-end readout application-specific integrated circuit (ASIC) dedicated to a multichannel-plate photodetector coupled to LYSO scintillating crystals. In our configuration, the crystals are oriented in the axial direction readout on both sides by individual photodetector channels allowing the spatial resolution and the detection efficiency to be independent of each other. Both energy signals and timing triggers from the photodetectors are required to be read out by the front-end ASIC. A current-mode charge-sensitive amplifier is proposed for this application. This paper presents performance characteristics of a 10-channel prototype chip designed and fabricated in a 0.35-?m complementary metal-oxide semiconductor process. The main results of simulations and measurements are presented and discussed. The gain of the chip is 13.1 mV/pC while the peak time of a CR-RC pulse shaper is 280 ns. The signal-to-noise ratio is 39 dB and the rms noise is 300 ?V/?(Hz). The nonlinearity is less than 3% and the crosstalk is about 0.2%. The power dissipation is less than 15 mW/channel. This prototype will be extended to a 64-channel circuit with integrated time-to-digital converter and analog-to-digital converter together for a high-sensitive small-animal positron emission tomography imaging system.
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Sparse reconstruction for quantitative bioluminescence tomography based on the incomplete variables truncated conjugate gradient method.
Opt Express
PUBLISHED: 12-18-2010
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In this paper, we present an incomplete variables truncated conjugate gradient (IVTCG) method for bioluminescence tomography (BLT). Considering the sparse characteristic of the light source and insufficient surface measurement in the BLT scenarios, we combine a sparseness-inducing (?1 norm) regularization term with a quadratic error term in the IVTCG-based framework for solving the inverse problem. By limiting the number of variables updated at each iterative and combining a variable splitting strategy to find the search direction more efficiently, it obtains fast and stable source reconstruction, even without a priori information of the permissible source region and multispectral measurements. Numerical experiments on a mouse atlas validate the effectiveness of the method. In vivo mouse experimental results further indicate its potential for a practical BLT system.
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Experimental Cerenkov luminescence tomography of the mouse model with SPECT imaging validation.
Opt Express
PUBLISHED: 12-18-2010
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Optical molecular imaging resulting from Cerenkov radiation has become a motivating topic recently and will potentially open new avenues for the study of small animal imaging. Cerenkov-based optical imaging taken from living animals in vivo has been studied with two-dimensional (2D) planar geometry and three-dimensional (3D) homogeneous mouse model. In this study, we performed 3D Cerenkov-based luminescence tomography (CLT) using a heterogeneous mouse model with an implanted Na(131)I radioactive source, which provided the accurate location for the reconstructed source. Furthermore, single photon emission computed tomography (SPECT) was utilized to verify the results of 3D CLT. We reconstructed the localization and intensity of an embedded radioactive source with various concentrations, and established a quantitative relationship between the radiotracer activity and the reconstructed intensity. The results showed the ability of in vivo CLT to recover the radioactive probe distribution in the heterogeneous mouse model and the potential of a SPECT imaging validation strategy to verify the results of optical molecular tomography.
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CYP3A-mediated generation of aldehyde and hydrazine in atazanavir metabolism.
Drug Metab. Dispos.
PUBLISHED: 12-09-2010
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Atazanavir (ATV) is an antiretroviral drug of the protease inhibitor class. Multiple adverse effects of ATV have been reported in clinical practice, such as jaundice, nausea, abdominal pain, and headache. The exact mechanisms of ATV-related adverse effects are unknown. It is generally accepted that a predominant pathway of drug-induced toxicity is through the generation of reactive metabolites. Our current study was designed to explore reactive metabolites of ATV. We used a metabolomic approach to profile ATV metabolism in mice and human liver microsomes. We identified 5 known and 13 novel ATV metabolites. Three potential reactive metabolites were detected and characterized for the first time: one aromatic aldehyde, one ?-hydroxyaldehyde, and one hydrazine. These potential reactive metabolites were primarily generated by CYP3A. Our results provide a clue for studies on ATV-related adverse effects from the aspect of metabolic activation. Further studies are suggested to illustrate the impact of these potential reactive metabolites on ATV-related adverse effects.
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De novo lipogenesis maintains vascular homeostasis through endothelial nitric-oxide synthase (eNOS) palmitoylation.
J. Biol. Chem.
PUBLISHED: 11-23-2010
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Endothelial dysfunction leads to lethal vascular complications in diabetes and related metabolic disorders. Here, we demonstrate that de novo lipogenesis, an insulin-dependent process driven by the multifunctional enzyme fatty-acid synthase (FAS), maintains endothelial function by targeting endothelial nitric-oxide synthase (eNOS) to the plasma membrane. In mice with endothelial inactivation of FAS (FASTie mice), eNOS membrane content and activity were decreased. eNOS and FAS were physically associated; eNOS palmitoylation was decreased in FAS-deficient cells, and incorporation of labeled carbon into eNOS-associated palmitate was FAS-dependent. FASTie mice manifested a proinflammatory state reflected as increases in vascular permeability, endothelial inflammatory markers, leukocyte migration, and susceptibility to LPS-induced death that was reversed with an NO donor. FAS-deficient endothelial cells showed deficient migratory capacity, and angiogenesis was decreased in FASTie mice subjected to hindlimb ischemia. Insulin induced FAS in endothelial cells freshly isolated from humans, and eNOS palmitoylation was decreased in mice with insulin-deficient or insulin-resistant diabetes. Thus, disrupting eNOS bioavailability through impaired lipogenesis identifies a novel mechanism coordinating nutritional status and tissue repair that may contribute to diabetic vascular disease.
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3D reconstruction of light flux distribution on arbitrary surfaces from 2D multi-photographic images.
Opt Express
PUBLISHED: 10-14-2010
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Optical tomography can demonstrate accurate three-dimensional (3D) imaging that recovers the 3D spatial distribution and concentration of the luminescent probes in biological tissues, compared with planar imaging. However, the tomographic approach is extremely difficult to implement due to the complexity in the reconstruction of 3D surface flux distribution from multi-view two dimensional (2D) measurements on the subject surface. To handle this problem, a novel and effective method is proposed in this paper to determine the surface flux distribution from multi-view 2D photographic images acquired by a set of non-contact detectors. The method is validated with comparison experiments involving both regular and irregular surfaces. Reconstruction of the inside probes based on the reconstructed surface flux distribution further demonstrates the potential of the proposed method in its application in optical tomography.
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Generalized free-space diffuse photon transport model based on the influence analysis of a camera lens diaphragm.
Appl Opt
PUBLISHED: 10-12-2010
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The camera lens diaphragm is an important component in a noncontact optical imaging system and has a crucial influence on the images registered on the CCD camera. However, this influence has not been taken into account in the existing free-space photon transport models. To model the photon transport process more accurately, a generalized free-space photon transport model is proposed. It combines Lambertian source theory with analysis of the influence of the camera lens diaphragm to simulate photon transport process in free space. In addition, the radiance theorem is also adopted to establish the energy relationship between the virtual detector and the CCD camera. The accuracy and feasibility of the proposed model is validated with a Monte-Carlo-based free-space photon transport model and physical phantom experiment. A comparison study with our previous hybrid radiosity-radiance theorem based model demonstrates the improvement performance and potential of the proposed model for simulating photon transport process in free space.
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The Chinese herbal medicine Sophora flavescens activates pregnane X receptor.
Drug Metab. Dispos.
PUBLISHED: 08-24-2010
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Sophora flavescens (SF) is an herbal medicine widely used for the treatment of viral hepatitis, cancer, viral myocarditis, gastrointestinal hemorrhage, and skin diseases. It was recently reported that SF up-regulates CYP3A expression. The mechanism of SF-induced CYP3A expression is unknown. In the current study, we tested the hypothesis that SF-induced CYP3A expression is mediated by the activation of pregnane X receptor (PXR). We used two cell lines, DPX2 and HepaRG, to investigate the role of PXR in SF-induced CYP3A expression. The DPX2 cell line is derived from HepG2 cells with the stable transfection of human PXR and a luciferase reporter gene linked with a human PXR response element identified in the CYP3A4 gene promoter. In DPX2 cells, SF activated PXR in a concentration-dependent manner. We used a metabolomic approach to identify the chemical constituents in SF, which were further analyzed for their effect on PXR activation and CYP3A regulation. One chemical in SF, N-methylcytisine, was identified as an individual chemical that activated PXR. HepaRG is a highly differentiated hepatoma cell line that mimics human hepatocytes. In HepaRG cells, N-methylcytisine significantly induced CYP3A4 expression, and this induction was suppressed by the PXR antagonist sulforaphane. These results suggest that SF induces CYP3A expression via the activation of PXR.
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Therapeutic role of rifaximin in inflammatory bowel disease: clinical implication of human pregnane X receptor activation.
J. Pharmacol. Exp. Ther.
PUBLISHED: 07-13-2010
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Human pregnane X receptor (PXR) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Rifaximin, a human PXR activator, is in clinical trials for treatment of IBD and has demonstrated efficacy in Crohns disease and active ulcerative colitis. In the current study, the protective and therapeutic role of rifaximin in IBD and its respective mechanism were investigated. PXR-humanized (hPXR), wild-type, and Pxr-null mice were treated with rifaximin in the dextran sulfate sodium (DSS)-induced and trinitrobenzene sulfonic acid (TNBS)-induced IBD models to determine the protective function of human PXR activation in IBD. The therapeutic role of rifaximin was further evaluated in DSS-treated hPXR and Pxr-null mice. Results demonstrated that preadministration of rifaximin ameliorated the clinical hallmarks of colitis in DSS- and TNBS-treated hPXR mice as determined by body weight loss and assessment of diarrhea, rectal bleeding, colon length, and histology. In addition, higher survival rates and recovery from colitis symptoms were observed in hPXR mice, but not in Pxr-null mice, when rifaximin was administered after the onset of symptoms. Nuclear factor ?B (NF-?B) target genes were markedly down-regulated in hPXR mice by rifaximin treatment. In vitro NF-?B reporter assays demonstrated inhibition of NF-?B activity after rifaximin treatment in colon-derived cell lines expressing hPXR. These findings demonstrated the preventive and therapeutic role of rifaximin on IBD through human PXR-mediated inhibition of the NF-?B signaling cascade, thus suggesting that human PXR may be an effective target for the treatment of IBD.
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In vivo quantitative reconstruction studies of bioluminescence tomography: effects of peak-wavelength shift and model deviation.
IEEE Trans Biomed Eng
PUBLISHED: 07-08-2010
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Bioluminescence tomography is a novel optical molecular imaging technology. The corresponding system, theory, and algorithmic frames have been set up. In the present study, we concentrated on the analysis of quantitative reconstruction deviation from peak-wavelength shift of luminescent source and the deviation of heterogeneous mouse model. The findings suggest that the reconstruction results are significantly affected by the peak-wavelength shift and deviation of anatomical structure animal models. Furthermore, the model deviations exhibit much more influence than the wavelength shift on the reconstruction results.
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In vivo quantitative bioluminescence tomography using heterogeneous and homogeneous mouse models.
Opt Express
PUBLISHED: 07-01-2010
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Bioluminescence tomography (BLT) is a new optical molecular imaging modality, which can monitor both physiological and pathological processes by using bioluminescent light-emitting probes in small living animal. Especially, this technology possesses great potential in drug development, early detection, and therapy monitoring in preclinical settings. In the present study, we developed a dual modality BLT prototype system with Micro-computed tomography (MicroCT) registration approach, and improved the quantitative reconstruction algorithm based on adaptive hp finite element method (hp-FEM). Detailed comparisons of source reconstruction between the heterogeneous and homogeneous mouse models were performed. The models include mice with implanted luminescence source and tumor-bearing mice with firefly luciferase report gene. Our data suggest that the reconstruction based on heterogeneous mouse model is more accurate in localization and quantification than the homogeneous mouse model with appropriate optical parameters and that BLT allows super-early tumor detection in vivo based on tomographic reconstruction of heterogeneous mouse model signal.
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Analysis of N1-acetyl-N2-formyl-5-methoxykynuramine/N1-acetyl-5-methoxy-kynuramine formation from melatonin in mice.
J. Pineal Res.
PUBLISHED: 05-27-2010
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The interactions of melatonin, a potent endogenous antioxidant, with reactive oxygen species generate several products that include N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) and N(1)-acetyl-5-methoxy-kynuramine (AMK). The physiological or pathological significance of AFMK/AMK formation during the process of melatonin metabolism in mammals has not been clarified. Using a metabolomic approach in the current study, the AFMK/AMK pathway was thoroughly investigated both in mice and humans. Unexpectedly, AFMK and AMK were not identified in the urine of humans nor in the urine, feces or tissues (including liver, brain, and eyes) in mice under the current experimental conditions. Metabolomic analysis did identify novel metabolites of AMK, i.e. hydroxy-AMK and glucuronide-conjugated hydroxy-AMK. These two newly identified metabolites were, however, not found in the urine of humans. In addition, oxidative stress induced by acetaminophen in the mouse model did not boost AFMK/AMK formation. These data suggest that AFMK/AMK formation is not a significant pathway of melatonin disposition in mice, even under conditions of oxidative stress.
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Macrophage fatty-acid synthase deficiency decreases diet-induced atherosclerosis.
J. Biol. Chem.
PUBLISHED: 05-17-2010
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Fatty acid metabolism is perturbed in atherosclerotic lesions, but whether it affects lesion formation is unknown. To determine whether fatty acid synthesis affects atherosclerosis, we inactivated fatty-acid synthase (FAS) in macrophages of apoE-deficient mice. Serum lipids, body weight, and glucose metabolism were the same in FAS knock-out in macrophages (FASKOM) and control mice, but blood pressure was lower in FASKOM animals. Atherosclerotic extent was decreased 20-40% in different aortic regions of FASKOM as compared with control mice on Western diets. Foam cell formation was diminished in FASKOM as compared with wild type macrophages due to increased apoAI-specific cholesterol efflux and decreased uptake of oxidized low density lipoprotein. Expression of the anti-atherogenic nuclear receptor liver X receptor alpha (LXRalpha; Nr1h3) and its downstream targets, including Abca1, were increased in FASKOM macrophages, whereas expression of the potentially pro-atherogenic type B scavenger receptor CD36 was decreased. Peroxisome proliferator-activated receptor alpha (PPARalpha) target gene expression was decreased in FASKOM macrophages. PPARalpha agonist treatment of FASKOM and wild type macrophages normalized PPARalpha target gene expression as well as Nr1h3 (LXRalpha). Atherosclerotic lesions were more extensive when apoE null mice were transplanted with LXRalpha-deficient/FAS-deficient bone marrow as compared with LXRalpha-replete/FAS-deficient marrow, consistent with anti-atherogenic effects of LXRalpha in the context of FAS deficiency. These results show that macrophage FAS deficiency decreases atherosclerosis through induction of LXRalpha and suggest that FAS, which is induced by LXRalpha, may generate regulatory lipids that cause feedback inhibition of LXRalpha in macrophages.
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GPU-based Monte Carlo simulation for light propagation in complex heterogeneous tissues.
Opt Express
PUBLISHED: 04-15-2010
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As the most accurate model for simulating light propagation in heterogeneous tissues, Monte Carlo (MC) method has been widely used in the field of optical molecular imaging. However, MC method is time-consuming due to the calculations of a large number of photons propagation in tissues. The structural complexity of the heterogeneous tissues further increases the computational time. In this paper we present a parallel implementation for MC simulation of light propagation in heterogeneous tissues whose surfaces are constructed by different number of triangle meshes. On the basis of graphics processing units (GPU), the code is implemented with compute unified device architecture (CUDA) platform and optimized to reduce the access latency as much as possible by making full use of the constant memory and texture memory on GPU. We test the implementation in the homogeneous and heterogeneous mouse models with a NVIDIA GTX 260 card and a 2.40GHz Intel Xeon CPU. The experimental results demonstrate the feasibility and efficiency of the parallel MC simulation on GPU.
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Qualitative simulation of photon transport in free space based on monte carlo method and its parallel implementation.
Int J Biomed Imaging
PUBLISHED: 04-09-2010
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During the past decade, Monte Carlo method has obtained wide applications in optical imaging to simulate photon transport process inside tissues. However, this method has not been effectively extended to the simulation of free-space photon transport at present. In this paper, a uniform framework for noncontact optical imaging is proposed based on Monte Carlo method, which consists of the simulation of photon transport both in tissues and in free space. Specifically, the simplification theory of lens system is utilized to model the camera lens equipped in the optical imaging system, and Monte Carlo method is employed to describe the energy transformation from the tissue surface to the CCD camera. Also, the focusing effect of camera lens is considered to establish the relationship of corresponding points between tissue surface and CCD camera. Furthermore, a parallel version of the framework is realized, making the simulation much more convenient and effective. The feasibility of the uniform framework and the effectiveness of the parallel version are demonstrated with a cylindrical phantom based on real experimental results.
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Truncated total least squares method with a practical truncation parameter choice scheme for bioluminescence tomography inverse problem.
Int J Biomed Imaging
PUBLISHED: 03-04-2010
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In bioluminescence tomography (BLT), reconstruction of internal bioluminescent source distribution from the surface optical signals is an ill-posed inverse problem. In real BLT experiment, apart from the measurement noise, the system errors caused by geometry mismatch, numerical discretization, and optical modeling approximations are also inevitable, which may lead to large errors in the reconstruction results. Most regularization techniques such as Tikhonov method only consider measurement noise, whereas the influences of system errors have not been investigated. In this paper, the truncated total least squares method (TTLS) is introduced into BLT reconstruction, in which both system errors and measurement noise are taken into account. Based on the modified generalized cross validation (MGCV) criterion and residual error minimization, a practical parameter-choice scheme referred to as improved GCV (IGCV) is proposed for TTLS. Numerical simulations with different noise levels and physical experiments demonstrate the effectiveness and potential of TTLS combined with IGCV for solving the BLT inverse problem.
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Proteomic profiling of human bone marrow mesenchymal stem cells under shear stress.
Mol. Cell. Biochem.
PUBLISHED: 02-26-2010
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Mesenchymal stem cells (MSCs) are promising seed cells for tissue engineering of blood vessels. As seed cells, MSCs must endure blood fluid shear stress after transplantation. It has been shown that fluid shear stress can regulate the proliferation and differentiation of MSCs. However, the effects of fluid shear stress on MSCs including the types of proteins modulated are still not well understood. In this study, we exposed human mesenchymal stem cells (HMSCs) to 3 dyn/cm(2) shear stress for 6 h and compared them to a control group using proteomic analysis. Thirteen specific proteins were affected by shear stress, 10 of which were up-regulated. Shear stress especially induced sustained increases in the expression of Annexin A2 and GAPDH, which have been specifically shown to affect HMSCs function. We present here the first comparative proteome analysis of effect of shear stress on HMSCs.
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Intracellular delivery of a membrane-impermeable enzyme in active form using functionalized gold nanoparticles.
J. Am. Chem. Soc.
PUBLISHED: 02-06-2010
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Gold nanoparticles were coated with a short peptide to promote intracellular delivery of membrane-impermeable proteins. Through microscopy and enzyme assays, we demonstrated the particles were able to transport functional enzymes into a variety of cell lines. Significantly, the transported proteins were able to escape from endosomes. Moreover, these particles showed no apparent cytotoxicity.
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Study on photon transport problem based on the platform of molecular optical simulation environment.
Int J Biomed Imaging
PUBLISHED: 02-05-2010
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As an important molecular imaging modality, optical imaging has attracted increasing attention in the recent years. Since the physical experiment is usually complicated and expensive, research methods based on simulation platforms have obtained extensive attention. We developed a simulation platform named Molecular Optical Simulation Environment (MOSE) to simulate photon transport in both biological tissues and free space for optical imaging based on noncontact measurement. In this platform, Monte Carlo (MC) method and the hybrid radiosity-radiance theorem are used to simulate photon transport in biological tissues and free space, respectively, so both contact and noncontact measurement modes of optical imaging can be simulated properly. In addition, a parallelization strategy for MC method is employed to improve the computational efficiency. In this paper, we study the photon transport problems in both biological tissues and free space using MOSE. The results are compared with Tracepro, simplified spherical harmonics method (SP(n)), and physical measurement to verify the performance of our study method on both accuracy and efficiency.
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Metabolism-mediated drug interactions associated with ritonavir-boosted tipranavir in mice.
Drug Metab. Dispos.
PUBLISHED: 01-26-2010
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Tipranavir (TPV) is the first nonpeptidic protease inhibitor used for the treatment of drug-resistant HIV infection. Clinically, TPV is coadministered with ritonavir (RTV) to boost blood concentrations and increase therapeutic efficacy. The mechanism of metabolism-mediated drug interactions associated with RTV-boosted TPV is not fully understood. In the current study, TPV metabolism was investigated in mice using a metabolomic approach. TPV and its metabolites were found in the feces of mice but not in the urine. Principal component analysis of the feces metabolome uncovered eight TPV metabolites, including three monohydroxylated, three desaturated, one dealkylated, and one dihydroxylated. In vitro study using human liver microsomes recapitulated five TPV metabolites, all of which were suppressed by RTV. CYP3A4 was identified as the primary enzyme contributing to the formation of four TPV metabolites (metabolites II, IV, V, and VI), including an unusual dealkylated product arising from carbon-carbon bond cleavage. Multiple cytochromes P450 (2C19, 2D6, and 3A4) contributed to the formation of a monohydroxylated metabolite (metabolite III). In vivo, RTV cotreatment significantly inhibited eight TPV metabolic pathways. In summary, metabolomic analysis revealed two known and six novel TPV metabolites in mice, all of which were suppressed by RTV. The current study provides solid evidence that the RTV-mediated boosting of TPV is due to the modulation of P450-dependent metabolism.
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Sex differences in face gender recognition: an event-related potential study.
Brain Res.
PUBLISHED: 01-22-2010
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Multiple level neurocognitive processes are involved in face processing in humans. The present study examined whether the early face processing such as structural encoding is modulated by task demands that manipulate attention to perceptual or social features of faces and such an effect, if any, is different between men and women. Event-related brain potentials were recorded from male and female adults while they identified a low-level perceptual feature of faces (i.e., face orientation) and a high-level social feature of faces (i.e., gender). We found that task demands that required the processing of face orientations or face gender resulted in modulations of both the early occipital/temporal negativity (N170) and the late central/parietal positivity (P3). The N170 amplitude was smaller in the gender relative to the orientation identification task whereas the P3 amplitude was larger in the gender identification task relative to the orientation identification task. In addition, these effects were much stronger in women than in men. Our findings suggest that attention to social information in faces such as gender modulates both the early encoding of facial structures and late evaluative process of faces to a greater degree in women than in men.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.