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Wang S, Huang LJ, Geng L, Scarpa F, Jiao Y, Peng HX. Significantly enhanced creep resistance of low volume fraction in-situ TiBw/Ti6Al4V composites by architectured network reinforcements. Sci Rep 2017; 7:40823. [PMID: 28094350 PMCID: PMC5240138 DOI: 10.1038/srep40823] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/12/2016] [Indexed: 11/13/2022] Open
Abstract
We present a new class of TiBw/Ti6Al4V composites with a network reinforcement architecture that exhibits a significant creep resistance compared to monolithic Ti6Al4V alloys. Creep tests performed at temperatures between 773 K and 923 K and stress range of 100 MPa-300 MPa indicate both a significant improvement of the composites creep resistance due to the network architecture made by the TiB whiskers (TiBw), and a decrease of the steady-state creep rates by augmenting the local volume fractions of TiBw in the network region. The deformation behavior is driven by a diffusion-controlled dislocation climb process. Moreover, the activation energies of these composites are significantly higher than that of Ti6Al4V alloys, indicating a higher creep resistance. The increase of the activation energy can be attributed to the TiBw architecture that severely impedes the movements of dislocation and grain boundary sliding and provides a tailoring of the stress transfer. These micromechanical mechanisms lead to a remarkable improvement of the creep resistance of these networked TiBw/Ti6Al4V composites featuring the special networked architecture.
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Yao H, Ma Y, Hong Z, Zhao L, Monaghan SA, Hu MC, Huang LJ. Activating JAK2 mutants reveal cytokine receptor coupling differences that impact outcomes in myeloproliferative neoplasm. Leukemia 2017; 31:2122-2131. [PMID: 28057939 PMCID: PMC5589508 DOI: 10.1038/leu.2017.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 02/06/2023]
Abstract
Janus tyrosine kinase 2 (JAK2) mediates downstream signaling of cytokine receptors in all hematological lineages, yet constitutively active JAK2 mutants are able to drive selective expansion of particular lineage(s) in myeloproliferative neoplasm (MPN). The molecular basis of lineage specificity is unclear. Here, we show that three activating JAK2 mutants with similar kinase activities in vitro elicit distinctive MPN phenotypes in mice by differentially expanding erythroid vs granulocytic precursors. Molecularly, this reflects the differential binding of JAK2 mutants to cytokine receptors EpoR and GCSFR in the erythroid vs granulocytic lineage and the creation of unique receptor/JAK2 complexes that generate qualitatively distinct downstream signals. Our results demonstrate that activating JAK2 mutants can differentially couple to selective cytokine receptors and change the signaling repertoire, revealing the molecular basis for phenotypic differences elicited by JAK2 (V617F) or mutations in exon 12. On the basis of these findings, receptor-JAK2 interactions could represent new targets of lineage-specific therapeutic approaches against MPN, which may be applicable to other cancers with aberrant JAK-STAT signaling.
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Jiao Y, Huang LJ, Duan TB, Wei SL, Kaveendran B, Geng L. Controllable two-scale network architecture and enhanced mechanical properties of (Ti5Si3+TiBw)/Ti6Al4V composites. Sci Rep 2016; 6:32991. [PMID: 27622992 PMCID: PMC5020694 DOI: 10.1038/srep32991] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 08/18/2016] [Indexed: 11/15/2022] Open
Abstract
Novel Ti6Al4V alloy matrix composites with a controllable two-scale network architecture were successfully fabricated by reaction hot pressing (RHP). TiB whiskers (TiBw) were in-situ synthesized around the Ti6Al4V matrix particles, and formed the first-scale network structure (FSNS). Ti5Si3 needles (Ti5Si3) precipitated in the β phase around the equiaxed α phase, and formed the secondary-scale network structure (SSNS). This resulted in increased deformation compatibility accompanied with enhanced mechanical properties. Apart from the reinforcement distribution and the volume fraction, the ratio between Ti5Si3 and TiBw fraction were controlled. The prepared (Ti5Si3 + TiBw)/Ti6Al4V composites showed higher tensile strength and ductility than the composites with a one-scale microstructure, and superior wear resistance over the Ti6Al4V alloy under dry sliding wear conditions at room temperature.
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Lai CH, Fung HS, Wu WB, Huang HY, Fu HW, Lin SW, Huang SW, Chiu CC, Wang DJ, Huang LJ, Tseng TC, Chung SC, Chen CT, Huang DJ. Highly efficient beamline and spectrometer for inelastic soft X-ray scattering at high resolution. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:325-332. [PMID: 24562553 DOI: 10.1107/s1600577513030877] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/10/2013] [Indexed: 06/03/2023]
Abstract
The design, construction and commissioning of a beamline and spectrometer for inelastic soft X-ray scattering at high resolution in a highly efficient system are presented. Based on the energy-compensation principle of grating dispersion, the design of the monochromator-spectrometer system greatly enhances the efficiency of measurement of inelastic soft X-rays scattering. Comprising two bendable gratings, the set-up effectively diminishes the defocus and coma aberrations. At commissioning, this system showed results of spin-flip, d-d and charge-transfer excitations of NiO. These results are consistent with published results but exhibit improved spectral resolution and increased efficiency of measurement. The best energy resolution of the set-up in terms of full width at half-maximum is 108 meV at an incident photon energy tuned about the Ni L3-edge.
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Yu SM, Kuo SC, Huang LJ, Sun SS, Huang TF, Teng CM. Vasorelaxation of Rat Thoracic Aorta Caused by Two Ca2+-Channel Blockers, HA-22 and HA-23. J Pharm Pharmacol 2011; 44:667-71. [PMID: 1359092 DOI: 10.1111/j.2042-7158.1992.tb05491.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Abstract
The pharmacological effects of HA-22 (2-(4′methoxyphenylmethyl)-3,4-dimethylpyrano[2,3-c]pyrazol-6(2H)-one) and HA-23 (2-(2′-thienylmethyl)-3,4-dimethylpyrano[2,3-c]pyrazol-6(2H)-one) on rat isolated thoracic aorta have been examined. In high potassium medium (60 Mm), Ca2+ (0·03–3 Mm)-induced vasoconstriction was inhibited by HA-22 and HA-23 (10–100 μg mL−1). Cromakalim-relaxed aortic rings precontracted with 15 Mm but not 60 Mm K+. However, HA-22, HA-23 and verapamil produced a greater relaxation in 60 Mm than in 15 Mm K+-induced contraction. The tonic contractions elicited by KCl (60 Mm) and Bay K 8644 (10−7 m) were also relaxed by the addition of HA-22 and HA-23. The phenylephrine concentration-response curves displayed antagonism by HA-22 and HA-23 (10–100 μg mL−1) in a non-competitive manner. The caffeine (10 Mm)-induced contraction and cAMP or cGMP levels were not affected by HA-22 or HA-23. It is concluded that HA-22 and HA-23 relaxed the rat aorta by suppressing the Ca2+ influx through both voltage-dependent and receptor-operated Ca2+ channels.
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Yuan YJ, Lu ZX, Huang LJ, Li Y, Lu FX, Bie XM, Teng YQ, Lin Q. Biodegradation of nicotine from tobacco waste extract by Ochrobactrum intermedium DN2. J Ind Microbiol Biotechnol 2007; 34:567-70. [PMID: 17333093 DOI: 10.1007/s10295-007-0212-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Accepted: 02/04/2007] [Indexed: 11/29/2022]
Abstract
Ochrobactrum intermedium DN2 was used to degrade nicotine in tobacco waste extracts. The optimal temperature and pH of nicotine degradation by strain DN2 was 30-37 degrees C and 7.0, respectively. Under these optimal conditions, the average degradation rate of nicotine in a 30L fed-batch culture was 140.5 mg 1(-1) h(-1). The results of this study indicate that strain DN2 may be useful for reducing the nicotine content of reconstituted tobacco.
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Yuan YJ, Lu ZX, Huang LJ, Bie XM, Lü FX, Li Y. Optimization of a medium for enhancing nicotine biodegradation by Ochrobactrum intermedium DN2. J Appl Microbiol 2006; 101:691-7. [PMID: 16907819 DOI: 10.1111/j.1365-2672.2006.02929.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To optimize a medium for nicotine degradation by Ochrobactrum intermedium DN2 in presence of yeast extract, glucose and Tween 80 using response surface methodology (RSM). METHODS AND RESULTS In this study, the effects of yeast extract, glucose and Tween 80 on nicotine degradation were investigated in flasks using a novel nicotine-degrading bacterium, O. intermedium DN2. A full factorial central composite design was applied in the design of experiments and in the analysis of the experimental data. The results showed that the most significant variable influencing nicotine degradation was yeast extract, followed by glucose, and then Tween 80. Moreover these three factors interacted with each other and combined to produce positive effects on nicotine degradation. The experimental data also allowed the development of an empirical model (P < 0.0001) describing the inter-relationship between independent and dependent variables. By solving the regression equation, the optimal values of the variables were determined as: yeast extracts 0.094%, glucose 0.101% and Tween 80 0.080%. Using the medium obtained, about 1,220 mg l(-1) of nicotine was degraded (95.55%) within 10 h at the specific biodegradation of 116.59 mg l(-1) h(-1) in 30-l bioreactor containing 25-l tobacco extract. CONCLUSIONS An optimal medium of nicotine degradation by the strain DN2 was obtained. SIGNIFICANCE AND IMPACT OF THE STUDY RSM proved to be reliable in developing the model, optimizing factors and analysing interaction effects. The results provide better understanding on the interactions between yeast extract, glucose and Tween 80 for nicotine biodegradation.
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Huang LJ, Constantinescu SN, Lodish HF. The N-terminal domain of Janus kinase 2 is required for Golgi processing and cell surface expression of erythropoietin receptor. Mol Cell 2001; 8:1327-38. [PMID: 11779507 DOI: 10.1016/s1097-2765(01)00401-4] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We show that Janus kinase 2 (JAK2), and more specifically just its intact N-terminal domain, binds to the erythropoietin receptor (EpoR) in the endoplasmic reticulum and promotes its cell surface expression. This interaction is specific as JAK1 has no effect. Residues 32 to 58 of the JAK2 JH7 domain are required for EpoR surface expression. Alanine scanning mutagenesis of the EpoR membrane proximal region reveals two modes of EpoR-JAK2 interaction. A continuous block of EpoR residues is required for functional, ligand-independent binding to JAK2 and cell surface receptor expression, whereas four specific residues are essential in switching on prebound JAK2 after ligand binding. Thus, in addition to its kinase activity required for cytokine receptor signaling, JAK is also an essential subunit required for surface expression of cytokine receptors.
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Shen HP, Zhou JG, Shen Y, Huang LJ. [The clinical assessment of zygomatic complex fracture treated via infraorbital incision and rigid fixation]. SHANGHAI KOU QIANG YI XUE = SHANGHAI JOURNAL OF STOMATOLOGY 2001; 10:321-2. [PMID: 14993963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
OBJECTIVE To investigate the clinical effect of zygomatic complex (ZC) fracture via infraorbital incision and rigid fixation. METHODS To clinically classify 65 cases with ZC fractures,which treated with open reduction and minor titanium-plate internal fixation. RESULTS (1) The operated area can be widely exposed via infraorbital incision. (2) ZC fractures can be reducted timely and correctly. (3) The fragments can be fixed rigidly with minor Ti-plaets. No injury to the facial nerve.The satisfactory rate of recovery was 95.4% (63/65). CONCLUSION Operation through infraorbital incision is suitable to ZC fractures.
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Lee FY, Lien JC, Huang LJ, Huang TM, Tsai SC, Teng CM, Wu CC, Cheng FC, Kuo SC. Synthesis of 1-benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole analogues as novel antiplatelet agents. J Med Chem 2001; 44:3746-9. [PMID: 11606139 DOI: 10.1021/jm010001h] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1-Benzyl-3-(5'-hydroxymethyl-2'-furyl)indazole (28, YC-1) was selected as the lead compound for systemic structural modification. After screening for antiplatelet activity, SARs of YC-1 analogues were established. Among these potent active derivatives, compounds 29, 30, 31, 44, and 45 functioned as potent activators of sGC and inhibitors of PDE5 with potency comparable to that of YC-1. In addition, compound 58 was found to be a selective and potent inhibitor of protease-activated receptor type 4 (PAR4)-dependent platelet activation.
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Wang JP, Chang LC, Huang LJ, Kuo SC. Inhibition of extracellular Ca(2+) entry by YC-1, an activator of soluble guanylyl cyclase, through a cyclic GMP-independent pathway in rat neutrophils. Biochem Pharmacol 2001; 62:679-84. [PMID: 11551512 DOI: 10.1016/s0006-2952(01)00725-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of a soluble guanylyl cyclase (sGC) activator, 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1), on formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated [Ca(2+)](i) elevation in rat neutrophils were examined. YC-1 produced a concentration-dependent inhibition of [Ca(2+)](i) elevation. Pretreatment of neutrophils with YC-1 did not enhance its inhibitory effect. YC-1 also inhibited the [Ca(2+)](i) changes caused by ionomycin. In a biphasic model, measuring the [Ca(2+)](i) stimulation by fMLP in a Ca(2+)-free medium followed by reintroduction of Ca(2+), YC-1 mainly affected Ca(2+) influx. YC-1 also inhibited active and passive Mn(2+) influx, and this inhibitory effect was not attenuated by the sGC inhibitor 6-anilino-5,8-quinolinequinone (LY83583). Sodium nitroprusside did not affect the fMLP-stimulated [Ca(2+)](i) changes. Pretreatment of neutrophils with the cyclic GMP-dependent protein kinase inhibitor 8-(4-chlorophenylthio) guanosine-3',5'-monophosphorothioate, Rp-isomer (Rp-8-pCPT-cGMPS), LY83583, the protein phosphatase 2B inhibitor cyclosporin A, or the protein kinase inhibitor staurosporine did not attenuate the inhibition of [Ca(2+)](i) by YC-1. YC-1 inhibited the fMLP-stimulated protein tyrosine phosphorylation. These results indicate that cyclic GMP does not play an important role in the regulation of [Ca(2+)](i) in rat neutrophils. Inhibition of fMLP-stimulated [Ca(2+)](i) changes by YC-1 is mainly via the blockade of Ca(2+) entry through the inhibition of tyrosine kinase activity, but not the stimulation of protein kinase C and protein phosphatase 2B.
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Rodriguez C, Huang LJ, Son JK, McKee A, Xiao Z, Lodish HF. Functional cloning of the proto-oncogene brain factor-1 (BF-1) as a Smad-binding antagonist of transforming growth factor-beta signaling. J Biol Chem 2001; 276:30224-30. [PMID: 11387330 DOI: 10.1074/jbc.m102759200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Using the plasminogen activator inhibitor (PAI) promoter to drive the expression of a reporter gene (mouse CD2), we devised a system to clone negative regulators of the transforming growth factor-beta (TGF-beta) signaling pathway. We infected a TGF-beta-responsive cell line (MvLu1) with a retroviral cDNA library, selecting by fluorescence-activated cell sorter single cells displaying low PAI promoter activity in response to TGF-beta. Using this strategy we cloned the proto-oncogene brain factor-1 (BF-1). BF-1 represses the PAI promoter in part by associating with both unphosphorylated Smad3 (in the cytoplasm) and phosphorylated Smad3 (in the nucleus), thus preventing its binding to DNA. BF-1 also associates with Smad1, -2, and -4; the Smad MH2 domain binds to BF-1, and the C-terminal segment of BF-1 is uniquely and solely required for binding to Smads. Further, BF-1 represses another TGF-beta-induced promoter (p15), it up-regulates a TGF-beta-repressed promoter (Cyclin A), and it reverses the growth arrest caused by TGF-beta. Our results suggest that BF-1 is a general inhibitor of TGF-beta signaling and as such may play a key role during brain development.
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38
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Xiang DQ, Cao HH, Cao YG, Yang JP, Huang LJ, Wang SC, Dai JR. [Construction of a genetic map and location of quantitative trait loci for yield component traits in maize by SSR markers]. YI CHUAN XUE BAO = ACTA GENETICA SINICA 2001; 28:778-84. [PMID: 11554353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Using 230 F2:3 lines derived from the hybrid of ND3138, a SSR genetic linkage map of maize (Zea mays L.) was constructed on which 80 markers distribute among 10 linkage groups and spanning maize genome about 2033.4 cM with average distance between markers being 25.42 cM. The 230 F2:3 lines were grown in a random design of one-row plot with three replication, and evaluated for ear length, bared tip, ear diameter, row number, kernel number row-1, one thousand grains weight, ear weight and grain weight plant-1. With interval mapping procedure, 30 QTLs were revealed for all traits, which distributed on 9 of 10 chromosomes of maize except chromosome 6 and accounted for from 9.5% to 55.3% of the total phenotypic variation. Genetic effects and gene action were also determined.
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Wang ZF, Peng XM, Huang LJ, Peng ZY, Tian GY. [Structure elucidation of glycan of a glycoconjugate SPPA-1 isolated from Spirulina platensis]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 2001; 36:356-9. [PMID: 12584858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
AIM To elucidate the structure of the glycan of SPPA-1, a glycoconjugate isolated from Spirulina platensis. METHODS Methylation analysis, GC/MS, and 1D, 2DNMR techniques were used to determine the structures of the glycoconjugate (SPPA-1). RESULTS SPPA-1 was only composed of alpha-D-glucose and shown to be a (1-->4) linked alpha-D-glucan to which a few glucosyl side chains are attached at O-6 of the glucosyl residues of the main chain. CONCLUSION The glycan of SPPA-1 is a new glucan.
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Huang LJ, Chen SX, Lou WJ. [Delayed cardioprotection of captopril in patients undergoing open heart surgery]. HUNAN YI KE DA XUE XUE BAO = HUNAN YIKE DAXUE XUEBAO = BULLETIN OF HUNAN MEDICAL UNIVERSITY 2001; 26:73-6. [PMID: 12536625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
OBJECTIVE To investigate whether there is delayed cardioprotection of captopril pretreatment in open heart surgery. METHODS Twenty patients with ventricular septal defect (VSD) undergone open heart surgery were randomly divided into captopril group (CAP group) and control group. In the CAP group, patients were pretreated with captopril (1 mg.kg-1, oral) at 48 hours before operation, No special treatment was given at the same time in the control group. Release of creatine phosphokinase-MB (CK-MB) and myocardial adenosine triphosphate (ATP) content was studied. Heart shock protein 70 (HSP70) in myocardum was examined using Western blotting analysis. RESULTS No statistically significant difference was found in release of CK-MB between control group and CAP group. ATP depletion was (1.40 +/- 0.56) mumol.g-1, (2.06 +/- 0.72) mumol.g-1 in CAP group and control group respectively (P < 0.05). Western blotting analysis showed that both group had HSP70 expression. In CAP group, HSP70 expression was higher than that in control group. CONCLUSION The results suggest that captopril pretreatment 48 hours before operation could reduce ATP depletion in pediatric patients of VSD during open-heart surgery, and HSP70 might be involved in the delayed cardioprotection induced by captopril.
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41
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Ko TC, Hour MJ, Lien JC, Teng CM, Lee KH, Kuo SC, Huang LJ. Synthesis of 4-alkoxy-2-phenylquinoline derivatives as potent antiplatelet agents. Bioorg Med Chem Lett 2001; 11:279-82. [PMID: 11212091 DOI: 10.1016/s0960-894x(00)00652-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In our continuing search for novel antiplatelet agents, 4-alkoxy derivatives of 2-phenylquinoline as well as related compounds were prepared. Through biological screening, a preliminary structure antiplatelet activity relationship was established. Compounds 5-ethyl-4-methoxy-2-phenylquinoline (8), 4-ethoxy-5-ethyl-2-phenylquinoline (9), 4-ethoxycarbonylmethoxy-5-ethyl-2-phenylquinoline (10), 4-ethoxycarbonylbutoxy-5-ethyl-2-phenylquinoline (12) and 5-ethyl-4-(N-ethylcarboxido)methoxy-2-phenylquinoline (17) all demonstrated potent antiplatelet activity. Among them, compound 8 was the most potent with an IC50 value of 0.08 microM and was about 3-fold more active than indomethacin. The mechanism of antiplatelet action of 8 is possibly through its inhibition on cyclooxygenase or thromboxane synthetase.
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Constantinescu SN, Huang LJ, Nam H, Lodish HF. The erythropoietin receptor cytosolic juxtamembrane domain contains an essential, precisely oriented, hydrophobic motif. Mol Cell 2001; 7:377-85. [PMID: 11239466 DOI: 10.1016/s1097-2765(01)00185-x] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We report that the erythropoietin receptor cytosolic juxtamembrane region is conformationally rigid and contains a hydrophobic motif, composed of residues L253, I257, and W258, that is crucial for Janus kinase 2 (JAK2) activation and receptor signaling. Alanine insertion mutagenesis shows that the orientation of this motif and not its distance from the membrane bilayer is critical. Intragenic complementation studies suggest that L253 is contained within an alpha helix functionally continuous to the transmembrane alpha helix. The alpha-helical orientation of L53 is required not for JAK2 activation but for activated JAK2 to induce phosphorylation of the erythropoietin receptor. This motif is highly conserved among cytokine receptors and couples ligand-induced conformational changes in the receptor to intracellular activation of JAK2.
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43
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Huang LJ, Tian GY, Wang ZF, Dong JB, Wu MP. [Studies on the glycoconjugates and glycans from Lycium barbarum L in inhibiting low density lipoprotein (LDL) peroxidation]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 2001; 36:108-11. [PMID: 12579875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
AIM To determine the effects of glycoconjugates and their glycans from Lycium barbarum L. on inhibiting low density lipoprotein (LDL) peroxidation. METHODS Using Cu(2+)-induced oxidation as a model, the oxidative production of thiobarbituric acid-reactive substances (TBARS) and the LDL electrophoresis migration on agarose gel were measured. RESULTS The effects of glycoconjugates and their glycans from Lycium barbarum L. on inhibiting LDL peroxidation were different, among them, glycoconjugate LbGp5 showed the best effect on inhibiting LDL peroxidation. CONCLUSION The glycoconjugates can inhibit LDL peroxidatin while their glycans showed no effects on inhibiting LDL peroxidation.
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44
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Wang ZF, Peng ZY, Huang LJ, Lu R, Tian GY. [Physico-chemical properties and biological activities of a glycoconjugate SPPA-1 from Spirulina platensis]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 2001; 36:112-5. [PMID: 12579876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
AIM To isolate polysaccharide from Spirulina platensis and determine its sugar position, molecular weight and biological activities. METHODS Sephadex G-75 and CM-Sephadex C-50 were used. The sugar position was analyzed by gas chromatography, the molecular weight was determined by GPC. The homogeneity of this glycoconjugate was determined by HPLC and CE. IR and NMR spectra were used to determine the glycosidic linkage. RESULTS SPPA-1 was a homogeneous glycoconjugate, its carbohydrate chain was composed of alpha-glucopyranan, carbohydrate content is 91.70%, Nitrogen content was 0.96%, the molecular weight was 69.00 x 10(4), SPPA-1 could eliminate O2-. radicals. CONCLUSION SPPA-1 was an antioxidative glycoconjugate from Spirulina platensis.
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45
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Huang LJ, Chen QM, Fan YD, Li HD, Liu BX. Formation of an icosahedral phase in ion-irradiated Fe/Cu multilayers. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/18/5/001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Hour MJ, Huang LJ, Kuo SC, Xia Y, Bastow K, Nakanishi Y, Hamel E, Lee KH. 6-Alkylamino- and 2,3-dihydro-3'-methoxy-2-phenyl-4-quinazolinones and related compounds: their synthesis, cytotoxicity, and inhibition of tubulin polymerization. J Med Chem 2000. [PMID: 11087572 DOI: 10.1021/jm000151c.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As part of our continuing search for potential anticancer candidates among 2-phenyl-4-quinolones and 2-phenyl-4-quinazolinones, two series of 6,7,2',3',4',5'-substituted 2-phenyl-4-quinazolinones and 6,2',3',4',5'-substituted 2,3-dihydro-2-phenyl-4-quinazolinones were synthesized and evaluated for cytotoxicity and as inhibitors of tubulin polymerization. In general, a good correlation was found between the two activities. Five of the 6-substituted heterocyclic 2-phenyl-4-quinozolinones (37-51) showed significant cytotoxicity against a panel of human tumor cell lines with EC(50) values in the low micromolar to nanomolar concentration ranges. Compound 38 was the most potent of these compounds, as well as the most potent inhibitor of tubulin polymerization in this series. The activity of 38 was in the same range as those of the antimitotic natural products, colchicine, podophyllotoxin, and combretastatin A-4. Substituted 2-phenyl-4-quinazolinones and 2, 3-dihydro-2-phenyl-4-quinazolinones also displayed highly selective cytotoxicity against the ovarian cancer 1A9 and P-gp resistant KB-VIN cell lines.
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Hour MJ, Huang LJ, Kuo SC, Xia Y, Bastow K, Nakanishi Y, Hamel E, Lee KH. 6-Alkylamino- and 2,3-dihydro-3'-methoxy-2-phenyl-4-quinazolinones and related compounds: their synthesis, cytotoxicity, and inhibition of tubulin polymerization. J Med Chem 2000; 43:4479-87. [PMID: 11087572 DOI: 10.1021/jm000151c] [Citation(s) in RCA: 317] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
As part of our continuing search for potential anticancer candidates among 2-phenyl-4-quinolones and 2-phenyl-4-quinazolinones, two series of 6,7,2',3',4',5'-substituted 2-phenyl-4-quinazolinones and 6,2',3',4',5'-substituted 2,3-dihydro-2-phenyl-4-quinazolinones were synthesized and evaluated for cytotoxicity and as inhibitors of tubulin polymerization. In general, a good correlation was found between the two activities. Five of the 6-substituted heterocyclic 2-phenyl-4-quinozolinones (37-51) showed significant cytotoxicity against a panel of human tumor cell lines with EC(50) values in the low micromolar to nanomolar concentration ranges. Compound 38 was the most potent of these compounds, as well as the most potent inhibitor of tubulin polymerization in this series. The activity of 38 was in the same range as those of the antimitotic natural products, colchicine, podophyllotoxin, and combretastatin A-4. Substituted 2-phenyl-4-quinazolinones and 2, 3-dihydro-2-phenyl-4-quinazolinones also displayed highly selective cytotoxicity against the ovarian cancer 1A9 and P-gp resistant KB-VIN cell lines.
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Chang CY, Huang LJ, Wang JP, Teng CM, Chen SC, Kuo SC. Synthesis and anti-platelet, anti-inflammatory and anti-allergic activities of methoxyisoflavanquinone and related compounds. Chem Pharm Bull (Tokyo) 2000; 48:964-73. [PMID: 10923824 DOI: 10.1248/cpb.48.964] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In a continuation of our search for novel anti-platelet agents, isoflavone quinone and isoflavanquinone were selected as lead compounds and the synthesis of their methoxy derivatives was carried out. Among them, the 4'- and 7-methoxy derivatives were successfully prepared, whereas the attempt to obtain 3'-methoxy derivatives resulted in their isomers, 3'-methoxyflavone quinone and 3'-methoxyflavanquinone, instead. After screening for their anti-platelet, anti-inflammatory and anti-allergic activities, a preliminary structure-activity relationship was established. Compounds 6c, 7a-c, 8c and 9a-c were found to exhibit significant activities. In particular, compound 7c demonstrated very potent anti-platelet, anti-inflammatory and anti-allergic activities and was then recommended for further pharmacological investigation.
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Huang LJ, Wang L, Ma Y, Durick K, Perkins G, Deerinck TJ, Ellisman MH, Taylor SS. NH2-Terminal targeting motifs direct dual specificity A-kinase-anchoring protein 1 (D-AKAP1) to either mitochondria or endoplasmic reticulum. J Cell Biol 1999; 145:951-9. [PMID: 10352013 PMCID: PMC2133123 DOI: 10.1083/jcb.145.5.951] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Subcellular localization directed by specific targeting motifs is an emerging theme for regulating signal transduction pathways. For cAMP-dependent protein kinase (PKA), this is achieved primarily by its association with A-kinase-anchoring proteins (AKAPs). Dual specificity AKAP1, (D-AKAP1) binds to both type I and type II regulatory subunits and has two NH2-terminal (N0 and N1) and two COOH-terminal (C1 and C2) splice variants (. J. Biol. Chem. 272:8057). Here we report that the splice variants of D-AKAP1 are expressed in a tissue-specific manner with the NH2-terminal motifs serving as switches to localize D-AKAP1 at different sites. Northern blots showed that the N1 splice is expressed primarily in liver, while the C1 splice is predominant in testis. The C2 splice shows a general expression pattern. Microinjecting expression constructs of D-AKAP1(N0) epitope-tagged at either the NH2 or the COOH terminus showed their localization to the mitochondria based on immunocytochemistry. Deletion of N0(1-30) abolished mitochondrial targeting while N0(1-30)-GFP localized to mitochondria. Residues 1-30 of N0 are therefore necessary and sufficient for mitochondria targeting. Addition of the 33 residues of N1 targets D-AKAP1 to the ER and residues 1-63 fused to GFP are necessary and sufficient for ER targeting. Residues 14-33 of N1 are especially important for targeting to ER; however, residues 1-33 alone fused to GFP gave a diffuse distribution. N1(14-33) thus serves two functions: (a) it suppresses the mitochondrial-targeting motif located within residues 1-30 of N0 and (b) it exposes an ER-targeting motif that is at least partially contained within the N0(1-30) motif. This represents the first example of a differentially targeted AKAP and adds an additional level of complexity to the PKA signaling network.
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Harada H, Becknell B, Wilm M, Mann M, Huang LJ, Taylor SS, Scott JD, Korsmeyer SJ. Phosphorylation and inactivation of BAD by mitochondria-anchored protein kinase A. Mol Cell 1999; 3:413-22. [PMID: 10230394 DOI: 10.1016/s1097-2765(00)80469-4] [Citation(s) in RCA: 498] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Signaling pathways between cell surface receptors and the BCL-2 family of proteins regulate cell death. Survival factors induce the phosphorylation and inactivation of BAD, a proapoptotic member. Purification of BAD kinase(s) identified membrane-based cAMP-dependent protein kinase (PKA) as a BAD Ser-112 (S112) site-specific kinase. PKA-specific inhibitors blocked the IL-3-induced phosphorylation on S112 of endogenous BAD as well as mitochondria-based BAD S112 kinase activity. A blocking peptide that disrupts type II PKA holoenzyme association with A-kinase-anchoring proteins (AKAPs) also inhibited BAD phosphorylation and eliminated the BAD S112 kinase activity at mitochondria. Thus, the anchoring of PKA to mitochondria represents a focused subcellular kinase/substrate interaction that inactivates BAD at its target organelle in response to a survival factor.
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