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Liu J, Li QX, Wang XJ, Zhang C, Duan YQ, Wang ZY, Zhang Y, Yu X, Li NJ, Sun JP, Yi F. β-Arrestins promote podocyte injury by inhibition of autophagy in diabetic nephropathy. Cell Death Dis 2016; 7:e2183. [PMID: 27054338 PMCID: PMC4855668 DOI: 10.1038/cddis.2016.89] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 11/16/2022]
Abstract
β-Arrestins are multifunctional proteins originally identified as negative adaptors of G protein-coupled receptors (GPCRs). Emerging evidence has also indicated that β-arrestins can activate signaling pathways independent of GPCR activation. This study was to elucidate the role of β-arrestins in diabetic nephropathy (DN) and hypothesized that β-arrestins contribute to diabetic renal injury by mediating podocyte autophagic process. We first found that both β-arrestin-1 and β-arrestin-2 were upregulated in the kidney from streptozotocin-induced diabetic mice, diabetic db/db mice and kidney biopsies from diabetic patients. We further revealed that either β-arrestin-1 or β-arrestin-2 deficiency (Arrb1−/− or Arrb2−/−) ameliorated renal injury in diabetic mice. In vitro, we observed that podocytes increased both β-arrestin-1 and β-arrestin-2 expression levels under hyperglycemia condition and further demonstrated that β-arrestin-1 and β-arrestin-2 shared common mechanisms to suppress podocyte autophagy by negative regulation of ATG12–ATG5 conjugation. Collectively, this study for the first time demonstrates that β-arrestin-1 and β-arrestin-2 mediate podocyte autophagic activity, indicating that β-arrestins are critical components of signal transduction pathways that link renal injury to reduce autophagy in DN. Modulation of these pathways may be an innovative therapeutic strategy for treating patients with DN.
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Liang H, Li QX, Shi BC, Chai ZH. Lattice Boltzmann simulation of three-dimensional Rayleigh-Taylor instability. Phys Rev E 2016; 93:033113. [PMID: 27078453 DOI: 10.1103/physreve.93.033113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Indexed: 06/05/2023]
Abstract
In this paper, the three-dimensional (3D) Rayleigh-Taylor instability (RTI) with low Atwood number (A(t)=0.15) in a long square duct (12W × W × W) is studied by using a multiple-relaxation-time lattice Boltzmann (LB) multiphase model. The effect of the Reynolds number on the interfacial dynamics and bubble and spike amplitudes at late time is investigated in detail. The numerical results show that at sufficiently large Reynolds numbers, a sequence of stages in the 3D immiscible RTI can be observed, which includes the linear growth, terminal velocity growth, reacceleration, and chaotic development stages. At late stage, the RTI induces a very complicated topology structure of the interface, and an abundance of dissociative drops are also observed in the system. The bubble and spike velocities at late stage are unstable and their values have exceeded the predictions of the potential flow theory [V. N. Goncharov, Phys. Rev. Lett. 88, 134502 (2002)]. The acceleration of the bubble front is also measured and it is found that the normalized acceleration at late time fluctuates around a constant value of 0.16. When the Reynolds number is reduced to small values, some later stages cannot be reached sequentially. The interface becomes relatively smoothed and the bubble velocity at late time is approximate to a constant value, which coincides with the results of the extended Layzer model [S.-I. Sohn, Phys. Rev. E 80, 055302(R) (2009)] and the modified potential theory [R. Banerjee, L. Mandal, S. Roy, M. Khan, and M. R. Guptae, Phys. Plasmas 18, 022109 (2011)]. In our simulations, the Graphics Processing Unit (GPU) parallel computing is also used to relieve the massive computational cost.
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Liu WQ, Wang WY, Wang JJ, Wang FQ, Lu C, Jin F, Zhang A, Zhang QM, Laan GVD, Xu YB, Li QX, Zhang R. Atomic-Scale Interfacial Magnetism in Fe/Graphene Heterojunction. Sci Rep 2015; 5:11911. [PMID: 26145155 PMCID: PMC4491707 DOI: 10.1038/srep11911] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/15/2015] [Indexed: 11/16/2022] Open
Abstract
Successful spin injection into graphene makes it a competitive contender in the race to become a key material for quantum computation, or the spin-operation-based data processing and sensing. Engineering ferromagnetic metal (FM)/graphene heterojunctions is one of the most promising avenues to realise it, however, their interface magnetism remains an open question up to this day. In any proposed FM/graphene spintronic devices, the best opportunity for spin transport could only be achieved where no magnetic dead layer exists at the FM/graphene interface. Here we present a comprehensive study of the epitaxial Fe/graphene interface by means of X-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations. The experiment has been performed using a specially designed FM1/FM2/graphene structure that to a large extent restores the realistic case of the proposed graphene-based transistors. We have quantitatively observed a reduced but still sizable magnetic moments of the epitaxial Fe ML on graphene, which is well resembled by simulations and can be attributed to the strong hybridization between the Fe 3dz2 and the C 2pz orbitals and the sp-orbital-like behavior of the Fe 3d electrons due to the presence of graphene.
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Li J, Li D, Tie C, Wu J, Wu Q, Li Q. Cisplatin-mediated cytotoxicity through inducing CYP4A 11 expression in human renal tubular epithelial cells. J Toxicol Sci 2015; 40:895-900. [PMID: 26558470 DOI: 10.2131/jts.40.895] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Li J, Tie CR, Li QX, Zheng F. Amlodipine prevents adriamycin-induced toxicity in cultured rat mesangial cells by up-regulation of Smad6, Smad7 expression. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 38:251-256. [PMID: 24975445 DOI: 10.1016/j.etap.2014.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 05/03/2014] [Accepted: 05/08/2014] [Indexed: 06/03/2023]
Abstract
Extensive studies have demonstrated that transforming growth factor-beta (TGF-β) plays an important role in the progression of renal diseases. A central component of TGF-β is the TGF-β family-specific Smad signal transduction pathway. TGF-β signals through Smad2, 4 to mediate renal fibrosis, whereas induction of Smad6, 7 inhibits renal fibrosis and inflammation. Amlodipine is the most frequently used antihypertensive drug among dihydropyridines. It is beneficial to the kidney and is widely used in treating kidney diseases. The aim of this study was to investigate effects of amlodipine on adriamycin-induced changes of lactate dehydrogenase (LDH) and expression of Smad6, 7 in rat mesangial cells. Results showed that amlodipine (10(-8) to 10(-5)mol/l) significantly decreased LDH activity in rat mesangial cells when given in combination with TGF-β₁ (P<0.01); amlodipine (10(-7), 10(-6)mol/l) significantly increased Smad6, 7 mRNA and protein expression in cells treated with adriamycin and TGF-β₁ (P<0.01). In conclusion, amlodipine protects against adriamycin-induced toxicity in rat mesangial cells by up-regulation of Smad6, 7 expressions.
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Kobayashi Y, Wang F, Li QX, Wang DZ. A microscopic model of the Tian-Calvet microcalorimeter, cell design for a faster response, and measurement by a continuous procedure. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:034101. [PMID: 24689600 DOI: 10.1063/1.4866681] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The transient heat conduction equation was used as the microscopic model of the Tian-Calvet microcalorimeter. It was verified by comparing simulated and experimental calorimetric curves and used to guide sample cell design for a faster response time, for which it gave the guidelines to minimize the heat flow distance and use a heat flux that is uniform and onto the whole face of the thermopile sensor. The resulting sample cell was disc-shaped with the sample powder placed in it as a thin 0.2 mm layer on a stainless steel base with a wall thickness of 0.5 mm that covered the whole face of the thermopile on which it was placed. The rise time of the heat response curve to a step change in sample temperature, which is the response time for measuring the differential heat released, was 45 s. The response curve from a gas dose returned to the baseline within 400 s, which is the time needed to measure the integrated heat in a pulsed dosage. The accuracy of the heats measured by the calorimeter was verified by comparison with data in the literature on the adsorption of ethanol and ammonia on HZSM-5 and adsorption of methanol and ammonia on SAPO-34. The differential heat of methanol adsorption on SAPO-34 at 333 K and ammonia adsorption on HZSM-5 at 423 K were measured by both the conventional discontinuous procedure and a new continuous procedure. In the continuous procedure, gas was continuously dosed at a very slow flow rate that was kept slow enough for the gas and adsorbate to reach quasi-equilibrium. The continuous procedure has the advantages of high resolution results and a simpler experimental procedure, and a calorimetric curve could be measured within 3 h.
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Li L, Dong TL, Li QX. Hybrid method of scattering from a dielectric target above a rough surface: TM case. APPLIED OPTICS 2013; 52:8759-8764. [PMID: 24513940 DOI: 10.1364/ao.52.008759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 11/17/2013] [Indexed: 06/03/2023]
Abstract
A hybrid method, combining analytic Kirchhoff approximation (KA) and numerical method of moment (MoM), is developed to solve the 2D scattering problem of a dielectric target with arbitrary cross section above a moderate perfect electric conductor (PEC) rough surface under TM-polarized tapered wave incidence. Consider the target as the MoM region and the rough surface as the KA region, the induced current on the rough surface is obtained through the KA method, which depends on the incident tapered wave and the field illuminating by current distribution on the target, leaving only unknowns on the target region. In order to reduce the computational costs further, the rough surface is truncated to speed up computation of the scattering contribution from the rough surface to the target. Compared with the conventional MoM, the hybrid method is very efficient to solve the composite scattering problem of target above rough surface, especially for long underlying rough surface. Simulation results validate the effectiveness and accuracy of the hybrid method.
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Cao YG, Li QX, Fu GY, Liu J, Guo HZ, Hu X, Li XJ. Depinning dynamics of two-dimensional magnetized colloids on a random substrate. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:155101. [PMID: 21389546 DOI: 10.1088/0953-8984/22/15/155101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We perform Langevin simulations on the depinning dynamics of two-dimensional magnetized colloids on a random substrate. On increasing the magnetic field strength, we find for the first time a crossover from plastic to smectic flows as well as a crossover from smectic to elastic crystal flows above depinning. For both the smectic and elastic crystal flows, a power-law scaling relationship could be obtained between the average velocity and applied driving force. The scaling exponent is found to be larger than 1 for smectic flow. But, for the elastic crystal flow, the scaling exponent is found to be less than 1. For the plastic flow, no power-law scaling relationship between the average velocity and applied driving force can be derived and history dependence of the depinning occurs. Within the crossover from plastic to smectic flows, a sudden decrease in the critical driving force is observed, and a sudden increase is found in the critical driving force across the crossover from smectic to elastic crystal flows, accompanied by a crossing of the curves of average velocity versus driving force.
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Kartika H, Li QX, Wall MM, Nakamoto ST, Iwaoka WT. Major phenolic acids and total antioxidant activity in Mamaki leaves, Pipturus albidus. J Food Sci 2008; 72:S696-701. [PMID: 18034755 DOI: 10.1111/j.1750-3841.2007.00530.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Three phenolic acids, (+)catechins, chlorogenic acid, and rutin, were identified and quantified in Mamaki leaves using a liquid chromatograph-mass spectrometer technique. Concentrations of (+)catechins, chlorogenic acid, and rutin varied from 1.1 to 5.0 mg/g of Mamaki leaves as determined in the extract using 0.5% acetic acid in 90% aqueous methanol. This study also quantified total antioxidant capacity using the photochemiluminescence method, which was expressed in equivalents to ascorbic acid (AA). Mamaki teas brewed for 30 min contained total antioxidant activity (TAA) between 238 and 259 mg AA/g of tea. Mamaki teas brewed for 1 h and stored at 4 h, 1 d, and 3 d at 4 degrees C had available TAA 293, 271, 172, and 163 mg AA/g of tea leaves, respectively. The concentrations of (+)catechins and rutin in Mamaki leaves are compared to other types of popular teas. Mamaki teas contained relatively low amounts of TAA compared to green teas and Lipton teas.
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Wang H, Ping J, Peng RX, Yue J, Xia XY, Li QX, Kong R, Hong JY. Changes of multiple biotransformation phase I and phase II enzyme activities in human fetal adrenals during fetal development. Acta Pharmacol Sin 2008; 29:231-8. [PMID: 18215353 DOI: 10.1111/j.1745-7254.2008.00738.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
AIM Fetal adrenal, which synthesizes steroid hormones, is critical to fetal growth and development. Our recent research showed that some xenobiotics could interfere with steroidogenesis and induce intrauterine growth retardation in rats. The study on the characteristics of biotransformation enzymes in fetal adrenals still seems to be important with respect to possible significance in xenobiotic-induced fetal development toxicity. In this study, the activities of several important xenobiotic-related phase I and phase II enzymes in human fetal adrenals were examined and compared with those in fetal livers. METHODS The activity and mRNA expression were determined by enzymatic analysis and RT-PCR. RESULTS The levels of cytochrome (CYP)2A6, CYP2E1, and CYP3A7 isozymes in fetal adrenals were 82%, 92%, and 33% of those in fetal livers, respectively. There was a good positive correlation between adrenal CYP2A6 activity and gestational time. The values of alpha glutathione S-transferase (GST), pi-GST, and microGST in adrenals were 0.5, 4.4, and 8.3-fold of those in the livers, respectively, and the activity of adrenal pi-GST was negatively correlated with gestational time. The uridine diphosphoglucuronyl transferase activities, which were measured using p-hydroxy-biphenyl and 7-hydroxy-4-methylcoumarin as substrates, were 9% and 3%, respectively, of those in the fetal livers. CONCLUSION Our investigation suggested that adrenal could be an important xenobiotic-metabolizing organ in fetal development and may play a potential role in xenobiotic-induced fetal development toxicity.
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Wang L, Gong L, Zhao E, Yu Z, Torimoto Y, Sadakata M, Li QX. Inactivation of Escherichia coli by O- water. Lett Appl Microbiol 2007; 45:200-5. [PMID: 17651219 DOI: 10.1111/j.1472-765x.2007.02170.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To clarify the effects of O(-) (atomic oxygen radical anion) water on the viability and morphological alteration of Escherichia coli. METHODS AND RESULTS O(-) water (OW) was prepared by bubbling of O(-)/argon (Ar) flux into deionized water. O(-) and hydrogen peroxide (H(2)O(2)) in the resultant OW were analysed by electron paramagnetic resonance and ultraviolet (UV) absorption spectroscopy. The population of E. coli treated by a typical OW of pH 4.30 +/- 0.20 [(2.5 +/- 0.8) x 10(-3) mmol l(-1) O(-); 0.5 +/- 0.2 mmol l(-1) H(2)O(2)) was reduced by more than 3 log CFU ml(-1) within 60 min at 30 degrees C. Through scanning electron microscopy observation, the OW-treated cells appeared dramatically collapsed. The release of nucleic acid induced by OW was identified by UV absorption spectroscopy. CONCLUSIONS O(-) water can result in inactivation of E. coli, nucleic acid release and cellular damage under the controlled laboratory conditions in excess of 15-30 min. Reactive oxygen species may play an important role in the inactivation process. SIGNIFICANCE AND IMPACT OF THE STUDY This study first revealed that OW could inactivate E. coli, which may be potentially useful in developing a novel approach for the microbial decontamination of food, water or heat-sensitive material.
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Fu H, Li J, Li QX, Xia L, Shao L. Protective effect of ligustrazine on accelerated anti-glomerular basement membrane antibody nephritis in rats is based on its antioxidant properties. Eur J Pharmacol 2007; 563:197-202. [PMID: 17362917 DOI: 10.1016/j.ejphar.2007.02.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 02/02/2007] [Accepted: 02/06/2007] [Indexed: 10/23/2022]
Abstract
Ligustrazine has a renoprotective effect against nephritis. In this study, we further characterized the renoprotective properties of ligustrazine in an experimental model using accelerated anti-glomerular basement membrane antibody (AGBM-Ab). Ligustrazine was given i.p. once daily at 50, 100 mg/kg for 15 days after singly giving i.v. of rabbit anti-rat glomerular basement membrane serum, and showed dose-dependent inhibition the elevation of urinary protein, serum creatinine and blood urea nitrogen as well as the development of glomerular histological changes. Ligustrazine (50 mg/kg) had no affect on glutathione (GSH) content, glutathione peroxidase and catalase activities, but decreased the malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity in nephritis induced by AGBM-Ab. Ligustrazine (100 mg/kg) significantly decreased MDA content while significantly increased GSH content and SOD, glutathione peroxidase, catalase activities of kidney tissues in the rats treated with AGBM-Ab alone. In conclusion, our results show that ligustrazine has protective activity against accelerated AGBM-Ab nephritis, and its renoprotective effect may be due to its antioxidant properties and inhibition reactive oxygen species (ROS).
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Li QX, Ke N, Zhou D, Chatterton J, Yu D, Wong-Staal F. A New Inducible RNAi Model for Cancer Target Validation In Vivo. Retrovirology 2005. [DOI: 10.1186/1742-4690-2-s1-s52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Wang D, Huelck K, Atkinson S, Li QX. Polychlorinated biphenyls in eggs of spectacled eiders (Somateria fischeri) from the Yukon-Kuskokwim Delta, Alaska. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2005; 75:760-7. [PMID: 16400558 DOI: 10.1007/s00128-005-0816-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Accepted: 07/30/2005] [Indexed: 05/06/2023]
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Keum YS, Li QX. Photolysis of octachloronaphthalene in hexane. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2004; 72:999-1005. [PMID: 15266697 DOI: 10.1007/s00128-004-0342-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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Keum YS, Li QX. Copper dissociation as a mechanism of fungal laccase denaturation by humic acid. Appl Microbiol Biotechnol 2004; 64:588-92. [PMID: 14564487 DOI: 10.1007/s00253-003-1460-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2003] [Revised: 08/20/2003] [Accepted: 09/07/2003] [Indexed: 10/26/2022]
Abstract
Effects of humic acid on removal of hydroxy polychlorobiphenyls (PCBs) with laccase from Trametes versicolor were studied. In the absence of humic acid, hydroxy PCBs were rapidly degraded by laccase. However, the rate constants decreased with increasing humic acid concentration, the reactions being completely inhibited at 150 mg l(-1) of humic acid. Peroxidase from Arthromyces ramosus was not inhibited by the same treatment. The activity of humic acid-deactivated laccase was completely restored by copper ions (500 microM of Cu2+ in 150 mg l(-1) of humic acid), but not by other metal ions (Zn2+, Fe2+ and Hg2+). Humic acid-deactivated laccase purified by gel permeation chromatography (GPC) showed no activity against 2,2'-azino-bis(3-ethylbenzthiazoline sulfonic acid) diammonium salt and 3,5-dichloro-4-hydroxybiphenyl, but its activity was restored by copper ion treatment. Humic acid-deactivated laccase showed similar properties, such as GPC retention time and copper ion requirements for activity, to those of laccase deactivated by nitrilotriacetic acid. The extent of humic acid inhibition, expressed as activity non-recoverable by copper ion treatment, increased over time more rapidly than that of the humic acid-free control. These results suggest that short-term inactivation of laccase, i.e., less than 1 day, is attributable to a depletion of copper ion.
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Peng BG, Li QX, Ren TY, Ahmad S, Chen SP, Chen P, Lin X. Group i metabotropic glutamate receptors in spiral ganglion neurons contribute to excitatory neurotransmissions in the cochlea. Neuroscience 2004; 123:221-30. [PMID: 14667457 DOI: 10.1016/j.neuroscience.2003.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Evidence has accumulated over the years supporting glutamate as the primary neurotransmitter used by hair cells in afferent cochlear neurotransmission. Besides acting on ionotropic glutamate receptors, glutamate also activates second messenger systems via G-protein-coupled metabotropic glutamate receptors (mGluRs) to modulate neuronal excitability. However, it is unclear whether mGluRs participate in cochlear neurotransmission. We present evidence directly supporting a functional role for group I metabotropic glutamate receptors (mGluRIs) in spiral ganglion (SG) neurons. The presence of mGluRI and downstream G-protein subunits was demonstrated by molecular biology and immunolabeling methods. Direct activation of mGluRIs in cultured SG neurons resulted in transient increases of intracellular Ca(++) concentration and transient inward currents that gave rise to firings of multiple action potentials. These responses showed mGluRI pharmacological specificity and quickly desensitized. We next examined changes in cochlear function after noise exposure as a result of pharmacologically manipulating cochlear glutamate neurotransmission. These in vivo tests showed that blocking non-N-methyl-D-aspartic acid glutamate receptors was sufficient to eliminate compound action potentials of the auditory nerve, and pharmacologically inhibiting mGluRIs in the cochlea did not significantly affect the hearing threshold. In contrast, blocking mGluRIs lowered the amplitude of compound action potentials at louder sound levels and reduced the noise-induced temporary threshold shift. Our results suggest that although mGluRIs did not initiate fast excitatory cochlear neurotransmission, their activation contributed to the growth of excitatory responses of the cochlea. As a result, the cochlea was more resistant to noise-induced temporary hearing losses without the activation of mGluRIs in SG neurons.
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Gai WP, Pountney DL, Power JHT, Li QX, Culvenor JG, McLean CA, Jensen PH, Blumbergs PC. alpha-Synuclein fibrils constitute the central core of oligodendroglial inclusion filaments in multiple system atrophy. Exp Neurol 2003; 181:68-78. [PMID: 12710935 DOI: 10.1016/s0014-4886(03)00004-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Multiple system atrophy (MSA) belongs to synucleinopathies and is characterized pathologically by oligodendroglial inclusions (GCIs) composed of 20- to 30-nm tubular filaments. alpha-Synuclein fibrils formed in vitro, however, range between 10 and 12 nm in diameter. To understand the relationship between alpha-synuclein and GCI filaments, we conducted structural analyses of GCIs in fixed brain sections and isolated from fresh-frozen MSA brains. In fixed brain sections, GCIs were composed of amorphous material-coated filaments up to 30 nm in size. The filaments were often organized in parallel bundles extending into oligodendroglial processes. In freshly isolated GCIs, progressive buffer washes removed amorphous material and revealed that GCI filaments consisted of 10-nm-sized central core fibrils that were strongly alpha-synuclein immunoreactive. Image analysis revealed that each core fibril was made of two subfibrils, and each subfibril was made of a string of 3- to 6-nm-sized particles probably alpha-synuclein oligomers. Immunogold labeling demonstrated that epitopes encompassing entire alpha-synuclein molecule were represented in the core fibrils, with the N-terminal 11-26 and C-terminal 108-131 amino acid residues most accessible to antibodies, probably exposed on the surface of the fibril. Our study indicates that GCI filaments are multilayered in structure, with alpha-synuclein oligomers forming the central core fibrils of the filaments.
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Sun YZ, Zhang HJ, Du ZC, Li QX, Li ZX. Organic pollution of street dust in the Handan City, China. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2003; 70:422-429. [PMID: 12592513 DOI: 10.1007/s00128-003-0003-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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Miao XS, Balazs GH, Murakawa SK, Li QX. Congener-specific profile and toxicity assessment of PCBs in green turtles (Chelonia mydas) from the Hawaiian Islands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2001; 281:247-253. [PMID: 11778957 DOI: 10.1016/s0048-9697(01)00835-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chemical pollution may play a role in the etiology of fibropapillomatosis in green turtles (Chelonia mydas). In this preliminary study, polychlorinated biphenyls (PCBs) were measured in the livers and adipose fats of green turtles collected after they were stranded on Oahu Island, Hawaii in 1992-1993. Average concentrations of total PCBs were 45-58 ng/g dry weight and 73-665 ng/g in the liver and adipose tissues, respectively. Hexachlorobiphenyls were predominant homologues, PCBs 153 and 138 were dominant congeners in all the turtle tissues. Among the most toxic coplanar congeners, in the order of abundance, were PCB 77 > 126 > 169. Estimated toxic equivalents (TEQs) of PCBs to 2,3,7,8-tetrachlorodibenzo-p-dioxin were 8-15 pg/g in the livers and 13-48 pg/g in the adipose tissues. PCB 126 contributed 85-91% of the total TEQs.
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Chiu YW, Li QX, Karu AE. Selective binding of polychlorinated biphenyl congeners by a monoclonal antibody: analysis by kinetic exclusion fluorescence immunoassay. Anal Chem 2001; 73:5477-84. [PMID: 11816577 DOI: 10.1021/ac0102462] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A previously described monoclonal antibody, S2B1, was highly selective for coplanar (non-ortho-chlorinated) PCB congeners in enzyme immunoassays that measured binding at equilibrium. In the present study, kinetic exclusion fluoroimmunoassay (KinExA) was used to determine the dissociation constants (Kd) and on and off rates (k(on), k(off)) for binding of various PCB congeners to affinity-purified S2B1 IgG and Fab fragments in solution. This method revealed that mono- and di-ortho-chlorinated PCBs were bound by S2B1, but the on rates were slower, and the off rates faster by 6-60-fold, than with congeners that had no ortho chlorines. Although the sensitivity of immunoassays may be improved by using competing haptens that S2B1 binds more weakly than the parent PCB, the KinExA results demonstrate that congener specificity is an intrinsic property of S2B1 and does not require weaker binding haptens. KinExA also provided new information on the percentage of active binding sites, valence, and effects of buffer, solvent, and biotinylation on S2B1. The advantages and drawbacks of KinExA for measuring antibody-ligand binding are described.
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Miao XS, Woodward LA, Swenson C, Li QX. Comparative concentrations of metals in marine species from French Frigate Shoals, North Pacific Ocean. MARINE POLLUTION BULLETIN 2001; 42:1049-1054. [PMID: 11763215 DOI: 10.1016/s0025-326x(01)00067-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Concentrations of arsenic, cadmium, chromium, copper, lead, mercury, selenium, and zinc were measured in coral, crab, eel, fish, lobster, and sediment samples collected from French Frigate Shoals, North Pacific Ocean. The sediments contained relatively high concentrations of selenium; moderate concentrations of arsenic, cadmium, copper and lead; and low concentrations of chromium and zinc. Metal concentrations were also determined in coral and crabs collected from the island of Oahu. Notably, a crab (Grapsus tenuicrustatus) and the undulated moray eel (Gymnothorax undulatus) exhibited high levels of copper and arsenic, respectively, relative to the other species studied. The concentrations of arsenic in the eel averaged 225 microg g(-1) dry wt, which was 3-12 times higher than that in all of the other species tested. The average concentration of copper in the crab was 343 microg g(-1) dry wt, 3-86 times greater than that in the other species studied. These data indicate background and comparative levels of the metals among the studied species. Lead levels in the coral (9-10 microg g(-1) dry wt) and crab (42-57 microg g(-1) dry wt) from Tern and Disappearing Islands were 23-283-fold greater than those from Oahu (0.4 and 0.2 microg g(-1) dry wt, respectively).
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Shan BE, Zhang JY, Li QX. [Human T cell and monocyte modulating activity of Rhizoma typhonii in vitro]. ZHONGGUO ZHONG XI YI JIE HE ZA ZHI ZHONGGUO ZHONGXIYI JIEHE ZAZHI = CHINESE JOURNAL OF INTEGRATED TRADITIONAL AND WESTERN MEDICINE 2001; 21:768-72. [PMID: 12575614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To study the immunological modulating activity of Rhizoma typhonii (RT) on lymphocytes in vitro. METHODS Effect of RT extract (RTE) on mice spleen cells and human lymphocytes proliferation was detected by sheep erythrocytes rosette forming test after lymphocytes had been isolated and purified. The activity of human killer cells and natrral killer (NK) cells was tested using 51 Cr free test. The production of cytokine of macrophages was examined using ELISA test and biological test and the phagocytic function of macrophage on tumor cell was determined using 3H incorporation assay. The chemical ingredients of RT were analyzed using chromatography and the molecular weight of their active principle was determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis technique (SDS-PAGE) method. RESULTS RTE could markedly stimulate the mice spleen cells and human lymphocytes to proliferate in a dose-effect dependent manner; the effector cell of RTE is T cells. RTE enhanced human killer cell, the allo-antigen specific cytotoxic T lymphocytes (CTL) activity and the nonspecific activity of NK cells. Furthermore, RTE stimulated macrophage to produce tumor necrosis factor (TNF-alpha) and interleukin-1 (IL-1), and enhanced phagocytic activity of macrophage to tumor cells. The elution of RTE from chromatography showed that the active principle of RT was glycoproteins in nature and had an apparent molecular weight of 66 kDa. CONCLUSION RTE has immunoenhancing activity to human T cell and macrophage, through stimulating the killer cell and phagocytosis of tumor cell and allo-antigen, which could be used clinically for modulating immune responses and for treating tumor and other diseases.
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Li QX, Hwang EC, Guo F. Occurrence of herbicides and their degradates in Hawaii's groundwater. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2001; 66:653-659. [PMID: 11443337 DOI: 10.1007/s001280058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2000] [Accepted: 02/12/2001] [Indexed: 05/23/2023]
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Campbell BC, McLean CA, Culvenor JG, Gai WP, Blumbergs PC, Jäkälä P, Beyreuther K, Masters CL, Li QX. The solubility of alpha-synuclein in multiple system atrophy differs from that of dementia with Lewy bodies and Parkinson's disease. J Neurochem 2001; 76:87-96. [PMID: 11145981 DOI: 10.1046/j.1471-4159.2001.00021.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Intracellular inclusions containing alpha-synuclein (alpha SN) are pathognomonic features of several neurodegenerative disorders. Inclusions occur in oligodendrocytes in multiple system atrophy (MSA) and in neurons in dementia with Lewy bodies (DLB) and Parkinson's disease (PD). In order to identify disease-associated changes of alpha SN, this study compared the levels, solubility and molecular weight species of alpha SN in brain homogenates from MSA, DLB, PD and normal aged controls. In DLB and PD, substantial amounts of detergent-soluble and detergent-insoluble alpha SN were detected compared with controls in grey matter homogenate. Compared with controls, MSA cases had significantly higher levels of alpha SN in the detergent-soluble fraction of brain samples from pons and white matter but detergent-insoluble alpha SN was not detected. There was an inverse correlation between buffered saline-soluble and detergent-soluble levels of alpha SN in individual MSA cases suggesting a transition towards insolubility in disease. The differences in solubility of alpha SN between grey and white matter in disease may result from different processing of alpha SN in neurons compared with oligodendrocytes. Highly insoluble alpha SN is not involved in the pathogenesis of MSA. It is therefore possible that buffered saline-soluble or detergent-soluble forms of alpha SN are involved in the pathogenesis of other alpha SN-related diseases.
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