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Luo XP, Wei YX, Huang HN, Hu DD, Pang EL. [Pure titanium denture large-span frameworks additively manufactured with selective laser melting]. Zhonghua Kou Qiang Yi Xue Za Zhi 2021; 56:646-651. [PMID: 34275219 DOI: 10.3760/cma.j.cn112144-20210405-00162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the accuracy of pure titanium and cobalt-chromium alloy frameworks fabricated using the additive manufacturing (AM) of selective laser melting technology (SLM) for the mandibular implant-supported fixed prostheses and the maxillary removable partial denture (RPD), and to provide a reference for clinical application of SLM pure titanium frameworks. Methods: One edentulous mandibular model with implants and screw fixed abutments at bilateral canines and the first molars was selected and used as the mandibular full arch implant-supported model. At the same time, a Kennedy class Ⅰ maxillary dentition defect model was selected. The digital models were obtained by scanning the dental models, and the metal frameworks of the mandibular full arch implant-supported denture and the maxillary RPD (design model) were designed using the 3 Shape software. Meanwhile, 12 mandibular frameworks in the cobalt-chromium alloy and the pure titanium (6 in each group were treated with heat treatment, while the other 6 were not treated), and 7 maxillary frameworks in the cobalt-chromium alloy and the pure titanium were respectively made by SLM with the improved dual-laser metal printer. The axial direction of the printing powder accumulation was taken as the Z-axis. During the design process, the software (3Shape Dental System 2018) automatically generated the X-axis and Y-axis, X axis was the sagittal axis of the dental model and Y axis was the coronal axis of the dental model. The deviation of the interface center of the abutment of the digital model of the mandibular frameworks from the design model in the X, Y and Z axes was analyzed. As for the trueness of the mandibular framework, the larger the deviation data was, the worse the trueness was. The deviation of the whole maxillary framework and 7 measuring points (palatal plate center point and bilateral occlusal rests, I bars, proximal plates) were analyzed. The fitness of the whole maxillary framework to the design model was expressed by root mean square (RMS) of the deviation data, and the fitness of measuring points was expressed by the mean±standard deviation of the data. The trueness differences of each group before and after heat treatment of the mandibular framework and the fitness of the maxillary framework were compared. Results: The cobalt-chromium alloy frameworks showed lower trueness on the X, Y, Z-axes [(96.3±12.1), (86.3±11.4), (61.2±13.2) μm] than did the pure Ti frameworks [(82.3±11.2), (72.2±10.2), (51.2±11.6) μm] by SLM, and the heat treatment could reduce the discrepancy between the SLM frameworks and STL models, for pure titanium frameworks [(62.4±11.3), (55.2±13.2), (41.3±10.8) μm] and for cobalt-chromium alloy [(84.5±10.5), (72.3±11.2), (54.2±11.6) μm]. For the thin RPD major frameworks, pure titanium had better fitness [(121.3±17.0) μm] than cobalt-chromium alloy [(174.0±18.3) μm] by SLM, and the difference was statistically significant (P<0.05). Conclusions: Pure titanium frameworks fabricated by SLM additive manufacturing technology exhibited better fitness and trueness than did the Co-Cr frameworks after heat treatment respectively, and this satisfied the requirements of implant-supported fixed prostheses and RPD major metal frameworks.
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Affiliation(s)
- X P Luo
- Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - Y X Wei
- Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - H N Huang
- Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - D D Hu
- Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - E L Pang
- Nanjing Qianzhi Intelligent Technology Limited Company, Nanjing 211111, China
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Zheng LZ, Liang XT, Li SR, Li YH, Hu DD. Fading and showing mechanisms of ancient color relics based on light scattering induced by particles. RSC Adv 2018; 8:1124-1131. [PMID: 35538968 PMCID: PMC9076970 DOI: 10.1039/c7ra11923b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/15/2017] [Indexed: 11/21/2022] Open
Abstract
Faded ancient color relics caused by particle light scattering could be shown by filling with trace non-volatile liquid.
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Affiliation(s)
- L. Z. Zheng
- Engineering Research Center of Historical and Cultural Heritage Protection
- Ministry of Education
- School of Materials Science and Engineering
- Shaanxi Normal University
- Xi’an 710062
| | - X. T. Liang
- Engineering Research Center of Historical and Cultural Heritage Protection
- Ministry of Education
- School of Materials Science and Engineering
- Shaanxi Normal University
- Xi’an 710062
| | - S. R. Li
- Engineering Research Center of Historical and Cultural Heritage Protection
- Ministry of Education
- School of Materials Science and Engineering
- Shaanxi Normal University
- Xi’an 710062
| | - Y. H. Li
- Engineering Research Center of Historical and Cultural Heritage Protection
- Ministry of Education
- School of Materials Science and Engineering
- Shaanxi Normal University
- Xi’an 710062
| | - D. D. Hu
- Engineering Research Center of Historical and Cultural Heritage Protection
- Ministry of Education
- School of Materials Science and Engineering
- Shaanxi Normal University
- Xi’an 710062
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Hu DD, Dai MH. [Progress in neoadjuvant and transformation therapy of pancreatic cancer]. Zhonghua Wai Ke Za Zhi 2017; 55:69-72. [PMID: 28056259 DOI: 10.3760/cma.j.issn.0529-5815.2017.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Pancreatic adenocarcinoma is a malignant disease with considerable metastatic potential.While surgical resection can be potentially curative, tumor recurrence remains an important cause of treatment failure.Neoadjuvant chemotherapy can increase rate of resectability by decreasing tumor burden and decrease recurrence rate by clearing microscopic disease in lymph nodes and vessels.Currently, neoadjuvant therapy is recommended for patients with resectable who has signs of high risks or borderline resectable pancreatic adenocarcinoma.However, no consensus exists in current literature on the evaluation of treatment response or operative timing.FOLFIRINOX has recently emerged as an effective chemotherapy regimen in several large clinical trials.
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Affiliation(s)
- D D Hu
- Depatment of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical Colloge, Beijing 100730, China
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Hu DD, Zhang RY, Zhang GQ, Wang HX, Ng TB. A laccase with antiproliferative activity against tumor cells from an edible mushroom, white common Agrocybe cylindracea. Phytomedicine 2011; 18:374-379. [PMID: 20739163 DOI: 10.1016/j.phymed.2010.07.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 06/02/2010] [Accepted: 07/12/2010] [Indexed: 05/29/2023]
Abstract
A laccase, with HIV-1 reverse transcriptase inhibitory activity (IC(50)=12.7 μM) and antiproliferative activity against HepG2 cells (IC(50)=5.6 μM) and MCF7 cells (IC(50)=6.5 μM), was purified from fresh fruiting bodies of the edible white common Agrocybe cylindracea mushroom. The laccase, which had a novel N-terminal sequence, displayed a molecular mass of 58 kDa within the range reported for most other mushroom laccases. The purification protocol entailed ion exchange chromatography on DEAE-cellulose, SP-Sepharose, and Q-Sepharose and gel filtration on Superdex 75. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose, but unadsorbed on SP-Sepharose. Its optimum pH was pH 3-4 and its optimum temperature was 50°C. The activity of the isolated laccase differed from one substrate to another. The ranking was ABTS>N,N-dimethyl-1,4-phenylenediamine>hydroquinone>catechol>2-methylcatechol>pyrogallol.
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Affiliation(s)
- D D Hu
- State Key Laboratory for Agrobiotechnology, Department of Microbiology, China Agricultural University, Beijing, China
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Zhang RY, Zhang GQ, Hu DD, Wang HX, Ng TB. A Novel Ribonuclease with Antiproliferative Activity from Fresh Fruiting Bodies of the Edible Mushroom Lyophyllum shimeiji. Biochem Genet 2010; 48:658-68. [DOI: 10.1007/s10528-010-9347-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 02/24/2010] [Indexed: 11/30/2022]
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Zhou YZ, Chen RJ, Tu SJ, Hu DD. Crystal structure of (N-(2-hydroxyl-1-naphthal)ethylenediamine)(iso-nicotinyl hydrazide)oxovanadium(V), [VO(C6H5N3O)(C13H13N2O)]. Z KRIST-NEW CRYST ST 2005. [DOI: 10.1524/ncrs.2005.220.14.531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Yan B, Hu DD, Knowles SK, Smith JW. Probing chemical and conformational differences in the resting and active conformers of platelet integrin alpha(IIb)beta(3). J Biol Chem 2000; 275:7249-60. [PMID: 10702295 DOI: 10.1074/jbc.275.10.7249] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Integrin alpha(IIb)beta(3) is the fibrinogen receptor that mediates platelet adhesion and aggregation. The ligand binding function of alpha(IIb)beta(3) is "activated" on the platelet surface by physiologic stimuli. Two forms of alpha(IIb)beta(3) can be purified from platelet lysates. These forms are facsimiles of the resting (Activation State-1 or AS-1) and the active (Activation State-2 or AS-2) conformations of the integrin found on the platelet surface. Here, the differences between purified AS-1 and AS-2 were examined to gain insight into the mechanism of activation. Four major findings are put forth. 1) The association rate (k(1)) between fibrinogen and the integrin is a key difference between AS-1 and AS-2. 2) Although the divalent ion Mn(2+) enhances the ligand binding function of AS-1, this ion is unable to convert AS-1 to AS-2. Therefore, its effect on integrin is unrelated to activation. 3) Peptide mass fingerprints indicate that the chemical structure of AS-1 and AS-2 are virtually identical, calling into question the idea that post-translational modifications are necessary for activation. 4) The two forms of alpha(IIb)beta(3) have significant conformational differences at three positions. These include the junction of the heavy and light chain of alpha(IIb), the divalent ion binding sites on alpha(IIb), and at a disulfide-bonded knot linking the amino terminus of beta(3) to the cysteine-rich domain. These observations indicate that integrin is activated by a series of specific conformational rearrangements in the ectodomain that increase the rate of ligand association.
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Affiliation(s)
- B Yan
- Program on Cell Adhesion, The Cancer Research Center at The Burnham Institute, La Jolla, California 92037, USA
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Hu DD, White CA, Panzer-Knodle S, Page JD, Nicholson N, Smith JW. A new model of dual interacting ligand binding sites on integrin alphaIIbbeta3. J Biol Chem 1999; 274:4633-9. [PMID: 9988699 DOI: 10.1074/jbc.274.8.4633] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The platelet integrin alphaIIbbeta3 mediates platelet aggregation and platelet adhesion. This integrin is the key to hemostasis and also to pathologic vascular occlusion. A key domain on alphaIIbbeta3 is the ligand binding site, which can bind to plasma fibrinogen and to a number of Arg-Gly-Asp (RGD)-type ligands. However, the nature and function of the ligand binding pocket on alphaIIbbeta3 remains controversial. Some studies suggest the presence of two ligand binding pockets, whereas other reports indicate a single binding pocket. Here we use surface plasmon resonance to show that alphaIIbbeta3 contains two distinct ligand binding pockets. One site binds to fibrinogen, and a separate site binds to RGD-type ligands. More importantly, however, the two ligand binding pockets are interactive. RGD-type ligands are capable of binding to alphaIIbbeta3 even when it is already occupied by fibrinogen. Once bound, RGD-type ligands induce the dissociation of fibrinogen from alphaIIbbeta3. This allosteric cross-talk has important implications for anti-platelet therapy because it suggests a novel approach for the dissolution of existing platelet thrombi.
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Affiliation(s)
- D D Hu
- Program on Cell Adhesion, Cancer Research Center, The Burnham Institute, La Jolla, California 92037, USA
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Abstract
Here we use a model RGD-containing ligand to study how Ca2+ and Mg2+ regulate ligand binding to beta3-integrins. Fab-9, an antibody that contains an optimized RGD loop in its antigen binding site (Barbas, C. F., Languino, L., and Smith, J. W. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 10003-10007), was used as the model ligand. Across a physiologic range of Mg2+, Fab-9 bound to both alphavbeta3 and alphaIIbbeta3 with a monophasic binding isotherm. Across the same range of Ca2+, the binding of Fab-9 to the beta3-integrins was biphasic. Low concentrations of Ca2+ (microM) promoted the binding of Fab-9. Higher concentrations of Ca2+ (m) blocked Fab-9 binding. These data suggest that Ca2+ binds to two distinct classes of sites on the beta3-integrins, with the low affinity Ca2+ binding site(s) being an inhibitory site. We designate this inhibitory site(s) as the I site. Further biochemical characterization showed that the I site has the following characteristics: 1) it is specific for Ca2+; 2) it is allosteric to the ligand binding site; 3) its occupation increases the dissociation rate between integrin and RGD ligand; and 4) occupation of the I site can induce cellular deadhesion.
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Affiliation(s)
- D D Hu
- Program on Cell Adhesion, Cancer Research Center, The Burnham Institute, La Jolla, California 92037, USA
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Hu DD, Lin EC, Kovach NL, Hoyer JR, Smith JW. A biochemical characterization of the binding of osteopontin to integrins alpha v beta 1 and alpha v beta 5. J Biol Chem 1995; 270:26232-8. [PMID: 7592829 DOI: 10.1074/jbc.270.44.26232] [Citation(s) in RCA: 200] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Osteopontin (OPN) is an extracellular matrix protein that binds to integrin alpha v beta 3. Here we demonstrate that two other integrins, alpha v beta 1 and alpha v beta 5, are also receptors for OPN. Human embryonic kidney 293 cells adhere to human recombinant osteopontin (glutathione S-transferase-osteopontin; GST-OPN) using integrin alpha v beta 1. When the 293 cells are transfected with the beta 5 subunit, they can also adhere to GST-OPN using integrin alpha v beta 5. Divalent cations regulate the binding of GST-OPN to both alpha v beta 1 and alpha v beta 5. Mg2+ and Mn2+ support the binding of GST-OPN to these integrins but Ca2+ does not. The highest affinity is observed in Mn2+. In the presence of this ion, the affinity of GST-OPN for alpha v beta 1 is 18 nM and the affinity for alpha v beta 5 is 48 nM. The antibody 8A2, which is an agonist for beta 1, promotes the adhesion of 293 cells to GST-OPN even when Ca2+ is present. This observation suggests that cellular events could modulate the affinity of alpha v beta 1 for OPN. Collectively, these findings prove that integrins alpha v beta 1, alpha v beta 3, and alpha v beta 5 have similar affinity for OPN. Therefore, all three integrins must be considered when evaluating the biological affects of OPN.
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Affiliation(s)
- D D Hu
- Cancer Research Center, La Jolla Cancer Research Foundation, California 92037, USA
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Abstract
Osteopontin (OPN) is an extracellular matrix protein that supports osteoclast adhesion to the bone by binding to integrin alpha v beta 3. We measured the binding between OPN and integrin alpha v beta 3 with recombinant human OPN and the urinary form of human OPN, uropontin. Recombinant OPN was expressed in Escherichia coli as a fusion protein with glutathione S-transferase and cleaved from glutathione S-transferase with Factor Xa. The mass of this form of OPN (rOP27) is 27,046 Da. rOP27 is truncated at arginine residue 228, 69 amino acids short of the native carboxyl terminus. Uropontin and rOP27 support RGD-dependent cell adhesion and to bind purified integrin alpha v beta 3 with similar affinities. Further study showed that OPN is the only known naturally occurring RGD-containing protein with a much greater affinity for alpha v beta 3 than for the platelet integrin alpha IIb beta 3. Most importantly, we find that physiologic levels of Ca2+ block cell adhesion to OPN. Measurement of binding constants between rOPN and purified integrin alpha v beta 3 with surface plasmon resonance showed that the affinity between rOPN and alpha v beta 3 is 26-fold lower in Ca2+ (Kd = 1.1 x 10(-8) M) than in Mn2+ (Kd = 4.3 x 10(-10) M) and 9-fold lower than in Mg2+ (Kd = 1.3 x 10(-9) M). In bone, the resorbing osteoclast generates elevated levels of extracellular Ca2+, therefore the findings presented here suggest a previously unappreciated mechanism for the modulation of bone resorption by extracellular Ca2+.
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Affiliation(s)
- D D Hu
- Department of Vascular Biology (VB-1), Scripps Research Institute, La Jolla, California 92037, USA
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Affiliation(s)
- D D Hu
- Department of Vascular Biology (VB-1), Scripps Research Institute, La Jolla, California 92037, USA
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Abstract
The association of L-tryptophan and some of its analogs, including three conformationally restricted analogs, with trp aporepressor (apo trpR) was studied by isothermal titration microcalorimetry. Contributions of the functional groups of a ligand to the free energy change, delta G degrees', and enthalpy change, delta H degree', of the interaction were evaluated on a molecular basis. Analogs without the alpha-amino group (i.e. desamino analogs) bind with a slightly higher affinity to the protein. On the other hand, descarboxy analogs show weaker binding to the apo trpR. In addition, it is found that there exists enthalpy-entropy compensation for the association of the congener series of ligands with the protein. The entropy change, delta S degree', appears to play a more important role in the binding of the conformationally restricted analogs than in the binding of L-tryptophan and the unlocked ligands.
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Affiliation(s)
- D D Hu
- Department of Chemistry, University of Mississippi, University 38677
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