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Abstract
The type 1 angiotensin receptor (AT(1)) activates an array of intracellular signalling pathways that control cell and tissue responses to the peptide hormone angiotensin II (AngII). The capacity of AT(1) receptors to initiate and maintain such signals has typically been explained on the basis of conventional heterotrimeric guanine nucleotide binding protein (G protein) activation, specifically G(q/11). Accumulating evidence from studies utilising a variety of AT(1) receptor mutants and AngII analogues indicates that some important downstream effects of AT(1) receptors are independent of classical G protein coupling. Importantly, AT(1) receptor-mediated endocytosis, tyrosine phosphorylation signalling and mitogen-activated protein kinase activation as well as transactivation of the epidermal growth factor receptor can occur in G(q/11)-uncoupled receptor mutants. These observations point to a functional partitioning of AT(1) receptor signals that permits separation of short-term AngII actions (e.g., vasoconstriction) from more extended events, such as pathological cell growth in heart and blood vessels, and may open up new avenues for selective antagonism.
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Chen T, Jiang G, Fu X, Wang L, Qian H, Wu K, Zhao S. Prognostic significance of CK19 mRNA expression measured by reverse-transcription polymerase chain reaction (RT-PCR) in peripheral blood of patients with non-small cell lung cancers treated by chemo-radiation. Int J Radiat Oncol Biol Phys 2004. [DOI: 10.1016/j.ijrobp.2004.06.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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103
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Qian H, Xiao Y, Bartold PM. Immunohistochemical localization and expression of fibromodulin in adult rat periodontium and inflamed human gingiva. Oral Dis 2004; 10:233-9. [PMID: 15196146 DOI: 10.1111/j.1601-0825.2004.00996.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The aim of this study was to determine the distribution and expression of fibromodulin in adult rat periodontal tissues and inflamed human gingiva. MATERIALS AND METHODS The distribution of fibromodulin in rat molar periodontium and human gingival tissue was studied by immunohistochemistry. The expression of fibromodulin mRNA from human gingival fibroblasts, periodontal ligament fibroblasts and osteoblasts was studied by reverse transcription-polymerase chain reaction (RT-PCR). For comparative purposes, the distribution and mRNA expression of collagen types I and III, as well as the two small leucine-rich proteoglycans decorin and biglycan were also studied. RESULTS In the adult rat periodontium, fibromodulin was distributed in the suprabasal gingival epithelium, gingival and periodontal fibroblasts as well as their surrounding extracellular matrices. Strong expression was noted in the palatal gingival tissues and the interfaces of the periodontal ligament with alveolar bone and cementum. In human gingival tissues, staining of fibromodulin was detected in the connective tissue of inflamed gingiva associated with both gingivitis and periodontitis; whereas, weak staining for this molecule was noted in healthy gingival tissues. The expression of mRNA for fibromodulin was strongest in the cultured osteoblasts. Periodontal ligament fibroblasts showed only a weak level of expression for fibromodulin mRNA. CONCLUSIONS Fibromodulin is differentially expressed throughout the periodontium being primarily associated with collagen type I in non-mineralized sites. In addition fibromodulin showed an upregulation in inflamed gingival tissue.
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Yang JH, Feng F, Qian H, Cheng H. Chemosensitization of breast carcinoma cells with the use of bcl-2 antisense oligodeoxynucleotide. Breast 2004; 13:227-31. [PMID: 15177426 DOI: 10.1016/j.breast.2003.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
This study was designed to observe whether the rates of apoptosis induced in the breast cancer cell line MCF-7 by 5-fluorouracil (5-FU) could be enhanced by transfecting bcl-2 antisense oligonucleotide (ASODN). In our experiment, bcl-2 ASODNs and control ODNs including untreated control, sense ODN and scrambled ODN, were transfected into MCF-7 cells. Changes in expression of the bcl-2 gene were examined by Western blot; cell growths were detected by MTT assay, and apoptosis rates were detected by flow cytometry (FCM). Expression of bcl-2 protein after transfection of bcl-2 ASODN was significantly lower than control ODNs. Moreover, incubation of MCF-7 with bcl-2 ASODN prior to 5-FU treatment caused remarkable loss of viable cells compared with all other control ODNs (P < 0.01). FCM showed the apoptosis rates for ASODN, untreated control, sense ODN and scrambled ODN (29.8 +/- 7.4)%, (8.0 +/- 2.3)%, (15.0 +/- 5.1)% and (16.5 +/- 7.1)%, respectively. Compared with control ODNs, ASODN achieved the strongest effect in terms of enhancing apoptosis (P < 0.01). These results suggest that combining bcl-2 ASODN with 5-FU led to synergistic cytotoxicity.
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Xiao Y, Qian H, Young WG, Bartold PM. Tissue Engineering for Bone Regeneration Using Differentiated Alveolar Bone Cells in Collagen Scaffolds. ACTA ACUST UNITED AC 2003; 9:1167-77. [PMID: 14670104 DOI: 10.1089/10763270360728071] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Regeneration of osseous defects by a tissue-engineering approach provides a novel means of treatment utilizing cell biology, materials science, and molecular biology. In this study the concept of tissue engineering was tested with collagen type I matrices seeded with cells with osteogenic potential and implanted into sites where osseous damage had occurred. Explant cultures of cells from human alveolar bone and gingiva were established. When seeded into a three-dimensional type I collagen-based scaffold, the bone-derived cells maintained their osteoblastic phenotype as monitored by mRNA and protein levels of the bone-related proteins including bone sialoprotein, osteocalcin, osteopontin, bone morphogenetic proteins 2 and 4, and alkaline phosphatase. These in vitro-developed matrices were implanted into critical-size bone defects in skulls of immunodeficient (SCID) mice. Wound healing was monitored for up to 4 weeks. When measured by microdensitometry the bone density within defects filled with osteoblast-derived matrix was significantly higher compared with defects filled with either collagen scaffold alone or collagen scaffold impregnated with gingival fibroblasts. New bone formation was found at all the sites treated with the osteoblast-derived matrix at 28 days, whereas no obvious new bone formation was identified at the same time point in the control groups. In situ hybridization for the human-specific Alu gene sequence indicated that the newly formed bone tissue resulted from both transplanted human osteoblasts and endogenous mesenchymal stem cells. The results indicate that cells derived from human alveolar bone can be incorporated into bioengineered scaffolds and synthesize a matrix, which on implantation can induce new bone formation.
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Zheng X, Tang L, Xu Y, Meng F, Zhu W, Gu Z, Qian H. [Evaluation of immunochromatographic test in the diagnosis of Plasmodium falciparum and Plasmodium vivax]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2003; 17:235-6. [PMID: 12563774] [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 evaluate the effectiveness of immunochromatographic test(ICT) in detecting Plasmodium falciparum and Plasmodium vivax in malaria endemic areas. METHODS ICT was used to detect P. falciparum and P. vivax among patients with fever in the outpatient clinics by comparason with thick blood smear method. RESULTS The sensitivity of ICT to detect P. falciparum and P. vivax was 96.7% and 90.4%, respectively. The specificity of ICT was 98.6%, and the coincidence rate was 94.7%. There is no cross reaction between P. falciparum and P. vivax. CONCLUSION ICT could detect P. falciparum and P. vivax simutaneously, being more rapid and simple than blood smear method.
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Huang W, Hu D, Gou S, Qian H, Fun HK, Raj S, Meng Q. Dinuclear copper(II) complexes with different bridging connectors. J Mol Struct 2003. [DOI: 10.1016/s0022-2860(03)00080-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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108
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Courtney JM, Zhao XB, Qian H, Sharma A. Modification of polymer surfaces: optimization of approaches. Perfusion 2003; 18 Suppl 1:33-9. [PMID: 12708763 DOI: 10.1191/0267659103pf633oa] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Modification of polymer surfaces to achieve a surface with enhanced compatibility is an important means of obtaining improved biomaterials. Techniques are available for altering the hydrophilicity or charge of a surface, attaching macromolecules or attempting to resemble cell membranes. Relevant to the clinical success of a modified surface is the modification procedure and a procedure based on incorporation as opposed to surface treatment has potential advantages. The modification of plasticized vinyl chloride (PVC) by the incorporation of cyclodextrins is described. In comparison to unmodified PVC controls, cyclodextrin incorporation reduced fibrinogen adsorption, with the extent of reduction dependent on the type and quantity of cyclodextrin incorporated.
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Zhou S, Tang L, Qian H, Zheng X, Luo M. [A new method for evaluating malaria surveillance effectiveness--establishment and application of an index system]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2002; 16:97-100. [PMID: 12078231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
AIM To establish a comprehensive index system which is suitable for evaluating the effectiveness of malaria surveillance schemes. METHODS Delphi method was used to screen the existed effectiveness evaluation indices by experts to determine key indices and weighted coefficients. RESULTS Three indices, i.e. autochthonous incidence, ratio of cases detected (ROCD) and ratio of introduced/imported cases were selected. Their weighted coefficients were 0.36, 0.31 and 0.33, respectively. An index system named the malaria surveillance effectiveness index (MSEI) was built up and formulated as [formula: see text] which was applied to study cost-effectiveness of the two malaria surveillance schemes (A and B). According to the formula, the MSEIs in the study areas using the schemes A and B were 48.56 and 45.93, respectively. However, the cost for increasing a score of MSEI by implementing the scheme A was four times as high as that by implementing the scheme B. CONCLUSION The MSEI is practicable for evaluating the overall effectiveness of malaria surveillance schemes, especially in the cost-effectiveness analysis and health-economic evaluation.
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Zhu W, Tang L, Zheng X, Luo M, Gu Z, Qian H, Qu J. [Diagnosis of Falciparum malaria by immunochromatographic test]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 2002; 16:94-6. [PMID: 12078230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
AIM To evaluate the applicability of rapid immunochromatographic test(ICT) for diagnosing falciparum malaria in outpatient clinics in endemic area. METHODS With thick blood smear method as control, ICT was used for the detection of P. falciparum. RESULTS The sensitivity and specificity of ICT in detecting P. falciparum was 94.7% and 90.3%, respectively. No cross-reaction with P. vivax was found (P > 0.05). CONCLUSION ICT is much more rapid and simple than thick blood smear method for the diagnosis of falciparum malaria, and can be applied in the outpatient clinics in endemic area.
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111
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Qian H. From discrete protein kinetics to continuous Brownian dynamics: A new perspective. Protein Sci 2002. [DOI: 10.1110/ps.ps.18902] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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112
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Qian H, Li C, Yue J. [Relationship between Streptococcus mutans, Lactobacillus spp. and lactate-producing level and nursing bottle caries]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2001; 19:369-71. [PMID: 12539685] [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 The study aimed to investigate the levels of Streptococcus mutans and Lactobacillus spp. as well as the relationship between lactate-productive and aciduric organisms and nursing bottle caries. METHODS Totally, 30 children of 2- to 2.5-year-old were divided into two groups, including the group of nursing bottle caries and the group of caries-free. Streptococcus mutans and Lactobacillus spp. were isolated from dental plaque of all the children. The amount of lactate produced was measured with a microlitre plate reader. RESULTS The isolation frequency of Streptococcus mutans and Lactobacillus spp. were both 100 percent in the children with nursing bottle caries, and that the composition of these bacteria from nursing bottle caries lesions was higher than that of caries-free dental surface. Lactate-producing level was higher in the caries group than that of the caries-free group. CONCLUSION This study suggests Streptococcus mutans and Lactobacillus spp. may be the major pathogenic bacteria leading to nursing bottle caries.
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Yang LP, Qian H, Liu AD. [The role substance P in cardiovascular response to intracerebroventricular acetylcholine in rabbit]. ZHONGGUO YING YONG SHENG LI XUE ZA ZHI = ZHONGGUO YINGYONG SHENGLIXUE ZAZHI = CHINESE JOURNAL OF APPLIED PHYSIOLOGY 2001; 17:326-395. [PMID: 21207687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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115
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Qian H. Association of -Arrestin 1 with the Type 1A Angiotensin II Receptor Involves Phosphorylation of the Receptor Carboxyl Terminus and Correlates with Receptor Internalization. Mol Endocrinol 2001. [DOI: 10.1210/me.15.10.1706] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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116
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Qian H, Pipolo L, Thomas WG. Association of beta-Arrestin 1 with the type 1A angiotensin II receptor involves phosphorylation of the receptor carboxyl terminus and correlates with receptor internalization. Mol Endocrinol 2001; 15:1706-19. [PMID: 11579203 DOI: 10.1210/mend.15.10.0714] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Arrestins bind to phosphorylated G protein-coupled receptors and participate in receptor desensitization and endocytosis. Although arrestins traffic with activated type 1 (AT(1A)) angiotensin II (AngII) receptors, the contribution of arrestins to AT(1A) receptor internalization is controversial, and the physical association of arrestins with the AT(1A) receptor has not been established. In this study, by coimmunoprecipitating AT(1A) receptors and beta-arrestin 1, we provide direct evidence for an association between arrestins and the AT(1A) receptor that was agonist- and time-dependent and contingent upon the level of beta-arrestin 1 expression. Serial truncation of the receptor carboxyl terminus resulted in a graded loss of beta-arrestin 1 association, which correlated with decreases in receptor phosphorylation. Truncation of the AT(1A) receptor to lysine(325) prevented AngII-induced phosphorylation and beta-arrestin 1 association as well as markedly inhibiting receptor internalization, indicating a close correlation between these receptor parameters. AngII-induced association was also dramatically reduced in a phosphorylation- and internalization-impaired receptor mutant in which four serine and threonine residues in the central portion of the AT(1A) receptor carboxyl terminus (Thr(332), Ser(335), Thr(336), Ser(338)) were substituted with alanine. In contrast, substitutions in another serine/threonine-rich region (Ser(346), Ser(347), Ser(348)) and at three PKC phosphorylation sites (Ser(331), Ser(338), Ser(348)) had no effect on AngII-induced beta-arrestin 1 association or receptor internalization. While AT(1A) receptor internalization could be inhibited by a dominant-negative beta-arrestin 1 mutant (beta arr1(319-418)), treatment with hyperosmotic sucrose to inhibit internalization did not abrogate the differences in arrestin association observed between the wild-type and mutant receptors, indicating that arrestin binding precedes, and is not dependent upon, receptor internalization. Interestingly, a substituted analog of AngII, [Sar(1)Ile(4)Ile(8)]-AngII, which promotes robust phosphorylation of the receptor but does not activate receptor signaling, stimulated strong beta-arrestin 1 association with the full-length AT(1A) receptor. These results identify the central portion of the AT(1A) receptor carboxyl terminus as the important determinant for beta-arrestin 1 binding and internalization and indicate that AT(1A) receptor phosphorylation is crucial for beta-arrestin docking.
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West NE, Qian H, Guzik TJ, Black E, Cai S, George SE, Channon KM. Nitric oxide synthase (nNOS) gene transfer modifies venous bypass graft remodeling: effects on vascular smooth muscle cell differentiation and superoxide production. Circulation 2001; 104:1526-32. [PMID: 11571247 DOI: 10.1161/hc3801.095693] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Pathological vascular remodeling in venous bypass grafts (VGs) results in smooth muscle cell (SMC) intimal hyperplasia and provides the substrate for progressive atherosclerosis, the principal cause of late VG failure. Nitric oxide (NO) bioactivity is reduced in VGs, in association with increased vascular superoxide production, but how these features relate to pathological VG remodeling remains unclear. We used gene transfer of the neuronal isoform of nitric oxide synthase (nNOS) to investigate how increased NO production modulates vascular remodeling in VGs and determined the effects on late VG phenotype. METHODS AND RESULTS New Zealand White rabbits (n=60) underwent jugular-carotid interposition bypass graft surgery with intraoperative adenoviral gene transfer of nNOS or beta-galactosidase. Vessels were analyzed after 3 days (early, to investigate acute injury/inflammation) or 28 days (late, to investigate SMC intimal hyperplasia). In early VGs, nNOS gene transfer significantly increased NOS activity and substantially reduced adhesion molecule expression and inflammatory cell infiltration. In late VGs, recombinant nNOS protein was no longer evident, but there were sustained effects on VG remodeling, resulting in a striking reduction in SMC intimal hyperplasia, a more differentiated intimal SMC phenotype, and reduced vascular superoxide production. CONCLUSIONS Intraoperative nNOS gene transfer has sustained favorable effects on VG remodeling and on the vascular phenotype of mature VGs. These findings suggest that early, transient modification of the response to vascular injury is a powerful approach to modulate VG biology and highlight the potential utility of NOS gene transfer as a therapeutic strategy in VGs.
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Abstract
Numerous theories have been propounded to explain the various aspects of tooth eruption, but no general consensus exists about some of the underlying mechanisms that govern these aspects. An important unresolved issue is the source of the motive forces that displace teeth. We proposed that supraosseous eruptive forces are generated by tooth socket distortions caused by functional jaw deformations. Previous studies used basic equations of static equilibrium to demonstrate that the concomitant stretching of the oblique periodontal ligament (PDL) fibers give rise to forces that may cause supraosseous tooth eruption. For a more rigorous and expanded analysis, we applied the finite element method (FEM). Three functional loads were considered, but the FEM calculations strongly suggested that all jaw deformations contribute to tooth extrusion. It was also demonstrated that the PDL fiber disruptions that are likely to occur with increased stretching can provide a mechanism to stabilize the erupted position.
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Qian H, Chen J, Katona TR. The influence of PDL principal fibers in a 3-dimensional analysis of orthodontic tooth movement. Am J Orthod Dentofacial Orthop 2001; 120:272-9. [PMID: 11552126 DOI: 10.1067/mod.2001.116085] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of mechanical loads on the tooth-alveolus complex are of particular concern in orthodontics. The concepts of center of resistance (CRes) and center of rotation (CRot) are used to characterize tooth responses to orthodontic loads. The mechanical environment (stresses and strains) associated with orthodontic tooth movement is a unique model in bone adaptation physiology. Numerous finite element models of varying complexity have been developed to calculate tooth movements and stress distributions within the alveolar bone and the periodontal ligament (PDL). In general, the PDL has been idealized as a homogeneous isotropic material. For this project, a 3-dimensional tooth/PDL/mandible/finite element model was developed in which, for the first time in such an analysis, the PDL's principal-fiber structure was also incorporated. Parametric analyses showed that the fiber orientation and the mechanical properties do not exert much influence on the locations of the CRes and the CRot and on the stress patterns within the bone and the PDL matrix. However, the absence of principal fibers produces not only different stress magnitudes, but also differences in stress patterns. Furthermore, the no-fiber-associated CRes and CRot are considerably separated from the cluster of fiber-influenced centers. It was concluded that it may be more realistic to incorporate "generic" principal fibers into finite element models than not to include them at all, despite the lack of reliable information about fibers.
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Zhu Y, Shi H, Qian H, Huang W, Hong Z, Zhang Y, Xu N, Zhang L, Liu D, Tong Z, Li S, Zhang L, Zheng W. [The phase II clinical trial of Seratia Marcescens Anticancer Vaccine (S311) for malignant pleural effusions]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2001; 4:296-8. [PMID: 21050583 DOI: 10.3779/j.issn.1009-3419.2001.04.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND To evaluate the effect and adverse reactions of Seratia Marcescens Anticancer Vaccine ( S311) in the treatment of malignant pleural effusions. METHODS 0. 32 mg of S311 was administered into intracavity once a week, for successive three weeks, after draining off the pleural cavity completely by thoracocentesis or chest drainage. RESULTS Two hundred and forty-one patients with malignant effusions finished the arrangement of S311 therapy. The overall response rate was 92. 1%. The main adverse reactions were fever and pleuritic pain. Some patients had chill, dyspnea, nausea and vomiting. Liver dysfunction was observed in a few cases. CONCLUSIONS S311 is an effective drug for malignant pleural effusions.
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Qian H. Nonequilibrium steady-state circulation and heat dissipation functional. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 64:022101. [PMID: 11497631 DOI: 10.1103/physreve.64.022101] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2000] [Indexed: 05/23/2023]
Abstract
A nonequilibrium steady-state (NESS), different from an equilibrium, is sustained by circular balance rather than detailed balance. The circular fluxes are driven by energy input and heat dissipation, accompanied by a positive entropy production. Based on a Master equation formalism for NESS, we show the circulation is intimately related to the recently studied Gallavotti-Cohen symmetry of heat dissipation functional, which in turn suggests a Boltzmann's formulalike relation between rate constants and energy in NESS. Expanding this unifying view on NESS to diffusion is discussed.
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Qian H, Hausman DB, Compton MM, Martin RJ, Della-Fera MA, Hartzell DL, Baile CA. TNFalpha induces and insulin inhibits caspase 3-dependent adipocyte apoptosis. Biochem Biophys Res Commun 2001; 284:1176-83. [PMID: 11414707 DOI: 10.1006/bbrc.2001.5100] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulation of fat cell number by apoptosis is proposed to be part of a normal physiological cycle in adipose growth and development. To investigate this process, cultured rat adipocytes were treated with various concentrations of tumor necrosis factor alpha (TNFalpha) and/or insulin to determine the roles of these factors in adipocyte apoptosis. The cells were analyzed by flow cytometry using a TUNEL assay. TNFalpha increased adipocyte apoptosis in a dose-dependent fashion. TNFalpha-mediated apoptosis was detectable within 6 h of treatment and continued to increase with time. Decreasing media insulin concentration from 8.5 to 0.85 nM resulted in increased adipocyte apoptosis, whereas high doses of insulin protected adipocytes from TNFalpha-induced apoptosis. TNFalpha-activated apoptosis was accompanied by an increase in caspase 3 activity and could be inhibited by a caspase 3-specific inhibitor. These data suggest that adipose tissue cell number is regulated, in part, by an apoptotic signaling pathway that involves TNFalpha, insulin, and caspase 3.
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Hanyaloglu AC, Vrecl M, Kroeger KM, Miles LE, Qian H, Thomas WG, Eidne KA. Casein kinase II sites in the intracellular C-terminal domain of the thyrotropin-releasing hormone receptor and chimeric gonadotropin-releasing hormone receptors contribute to beta-arrestin-dependent internalization. J Biol Chem 2001; 276:18066-74. [PMID: 11278484 DOI: 10.1074/jbc.m009275200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have previously shown that the mammalian gonadotropin-releasing hormone receptor (GnRHR), a unique G-protein-coupled receptor (GPCR) lacking an intracellular carboxyl tail (C-tail), does not follow a beta-arrestin-dependent internalization pathway. However, internalization of a chimeric GnRHR with the thyrotropin-releasing hormone receptor (TRHR) C-tail does utilize beta-arrestin. Here, we have investigated the sites within the intracellular C-tail domain that are important for conferring beta-arrestin-dependent internalization. In contrast to the chimeric GnRHR with a TRHR C-tail, a chimeric GnRHR with the catfish GnRHR C-tail is not beta-arrestin-dependent. Sequence comparisons between these chimeric receptors show three consensus phosphorylation sites for casein kinase II (CKII) in the TRHR C-tail but none in the catfish GnRHR C-tail. We thus investigated a role for CKII sites in determining GPCR internalization via beta-arrestin. Sequential introduction of three CKII sites into the chimera with the catfish C-tail (H354D,A366E,G371D) resulted in a change in the pattern of receptor phosphorylation and beta-arrestin-dependence, which only occurred when all three sites were introduced. Conversely, mutation of the putative CKII sites (T365A,T371A,S383A) in the C-tail of a beta-arrestin-sensitive GPCR, the TRHR, resulted in decreased receptor phosphorylation and a loss of beta-arrestin-dependence. Mutation of all three CKII sites was necessary before a loss of beta-arrestin-dependence was observed. Visualization of beta-arrestin/GFP redistribution confirmed a loss or gain of beta-arrestin sensitivity for receptor mutants. Internalization of receptors without C-tail CKII sites was promoted by a phosphorylation-independent beta-arrestin mutant (R169E), suggesting that these receptors do not contain the necessary phosphorylation sites required for beta-arrestin-dependent internalization. Apigenin, a specific CKII inhibitor, blocked the increase in receptor internalization by beta-arrestin, thus providing further support for the involvement of CKII. This study presents evidence of a novel role for C-tail CKII consensus sites in targeting these GPCRs to the beta-arrestin-dependent pathway.
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Qian H, Yang LP, Wei ZY, Liu AD, Tian H, Yang SF. Central norepinephrine pathways are involved in cardiovascular response to intracerebroventricular substance P. Acta Pharmacol Sin 2001; 22:349-54. [PMID: 11742588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
AIM To study the role of norepinephrine system in the cardiovascular response to intracerebroventricular substance P (SP) in rabbit. METHODS SP was given intracerebroventricularly in anesthetized rabbits pretreated with the catecholaminergic neurotoxin, 6-hydroxydopamine (6-OHDA). The density and affinity of SP receptors on synaptosomal membranes of the hypothalamus and the ventral medulla of rabbits were determined by [125I]SP receptor assay. Arterial blood pressure and heart rate were recorded. RESULTS Intracerebroventricular (icv) pretreatment of rabbits with 6-OHDA, reduced norepinephrine in the hypothalamus (by 86.7 %) and in the ventral medulla (by 77.0 %) respectively. The pressor response and tachycardia of these rabbits to icv SP (3.55 nmol . kg-1) were attenuated. The density and the affinity of SP receptors in the hypothalamus and the ventral medulla of 6-OHDA-lesioned rabbits were decreased. The Bmax (pmol . g-1 protein) of SP receptors in hypothalamus and the ventral medulla are 108 +/- 5, 35.9 +/- 2.2 in control group, and 42 +/- 18, 20 +/- 5 in 6-OHDA-lesioned rabbits, respectively. Kd (nmol . L-1) of SP receptors in the two regions are 0.015 +/- 0.004, 0.014 +/- 0.006 in control group and 0.029 +/- 0.001, 0.015 +/- 0.003 in 6-OHDA group. There is a significant difference of Bmax (P < 0.01) and Kd (P < 0.01, P < 0.05) in both regions between 6-OHDA groups and control groups. CONCLUSION The results suggested that central norepinephrine pathways are involved in the cardiovascular response to icv SP.
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