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Tian L, Catt JW, O'Neill C, King NJ. Expression of immunoglobulin superfamily cell adhesion molecules on murine embryonic stem cells. Biol Reprod 1997; 57:561-8. [PMID: 9282991 DOI: 10.1095/biolreprod57.3.561] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The expression of cell adhesion molecules of the Ig superfamily (Ig-CAM) were examined on embryonic stem (ES) cells during culture in vitro. ES cells maintained an undifferentiated phenotype when cultured in the presence of leukemia inhibitory factor (LIF) or with fibroblast feeder cells; > 90% of cells reacted positively to an antibody (ECMA-7) that marks undifferentiated ES cells. Using flow cytometry, high concentrations of ICAM-1, VCAM-1, and NCAM antigens were detected on undifferentiated ES cells, but their specific receptors, Mac-1, LFA-1, and VLA-4, were not detected. There was also no class I or II major histocompatibility complex (MHC) antigen expression. The ICAM-1 expressed was functional, since anti-ICAM-1 significantly (p < 0.0001) blocked ES cell-lymphocyte binding. Ig-CAM and MHC-1 expression on undifferentiated ES cells was not up-regulated by treatment of cells with interferon-gamma (IFN-gamma), tumor necrosis factor alpha, or flavivirus infection, agents that up-regulate these molecules in other embryonic cell types. Twelve hours after LIF withdrawal, ICAM-1 and NCAM expression decreased significantly, while VCAM-1 was undetectable. However, morphology and ECMA-7 expression remained unchanged. Similar patterns of expression were seen on ES cells maintained on fibroblast feeder cells. This suggests that LIF or other cytokines may maintain the expression of Ig-CAMs on undifferentiated cells. Differentiation was induced by dimethyl sulfoxide treatment for 14 days. Cells changed from a colony-forming to a monolayer morphology, and approximately 60% of the cell population no longer expressed ECMA-7. In these cells, VCAM-1 was undetectable and ICAM-1 and NCAM had declined to low levels. In these differentiated cells, ICAM-1 and MHC-1 were inducible by IFN-gamma. This study suggests that the pattern of expression of the Ig-CAMs in ES cells may have a role in defining the phenotype of differentiated and undifferentiated cells.
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Richards VM, Buss E, Tian L. Effects of modulator phase for comodulation masking release and modulation detection interference. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1997; 102:468-476. [PMID: 9228809 DOI: 10.1121/1.419719] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In an effort to evaluate the importance of across-frequency comparisons of envelope patterns in comodulation masking release (CMR) experiments and to compare joint effects of target-masker frequency separation for both CMR and modulation detection interference (MDI) tasks, thresholds were measured for three tasks. These tasks were: (a) the detection of sinusoidal amplitude modulation (SAM) of a tone, (b) the detection of a reduction in the modulation depth of a fully modulated SAM tone, and (c) the detection of a tone added to a narrow band of noise. Thresholds were obtained for the target alone and for the target presented with two maskers. For the detection of SAM, thresholds did not depend on whether the modulation patterns of the target and masker elements were the same or random. For the latter two tasks, modulator phase effects were apparent for target-masker frequency separations less than 1-2 oct. In contrast, past work has shown that observers can compare modulator envelope phases across frequency separations larger than 1-2 oct [Strickland et al., J. Acoust. Soc. Am. 86, 2160-2166 (1989); Yost and Sheft, J. Acoust. Soc. Am. 85, 848-857 (1989)]. In a second experiment, thresholds for the detection of SAM were obtained after prolonged exposure to a fully modulated SAM tone. For four of the five observers, modulation-rate specific adaptation was obtained for test/adapting carrier-frequency separations approaching 2 oct below and 1 oct above the adaptor.
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Abstract
Autoantibodies to centromere proteins (anti-CENPs) and to topoisomerase-I are highly specific for scleroderma. Unlike most autoantibodies in other diseases, these autoantibodies are mutually exclusive. We have analysed the idiotypes (Ids) expressed by anti-CENP-B, antitopoisomerase-I, and IgGs from 20 scleroderma patients. Rabbit anti-Ids were prepared to antitopoisomerase-I from two scleroderma patients, and to anti-CENP-B from four patients. These six anti-Ids were used to study the purified autoantibodies from 20 scleroderma patients: four antitopoisomerase-I, 10 anti-CENP-B, and six purified IgG from scleroderma patients who were negative for both autoantibodies. In addition, we studied sera from 40 normal autoantibody-negative controls, and sera and purified immunoglobulins from 17 systemic lupus erythematosus (SLE) patients containing high titres of anti-double-stranded DNA, and/or autoantibodies to extractable nuclear antigens (ENA). Using direct binding, and competitive inhibition ELISAs and immunoblots, we identified an Id present in the heavy chains of all the affinity-purified antitopoisomerase-I, and anti-CENP-B. Interestingly, this Id was also present in the immunoglobulins of the scleroderma patients who had neither of the two autoantibodies. By contrast, cross-reactive Id-EM was not found in the sera or immunoglobulins from 17 SLE patients, or in the sera from 40 normal subjects. Several samples from two patients showed that this cross-reactive Id-EM was stable over time. The scleroderma disease-specific autoantibodies may be identified through a common structural feature at the variable region of the heavy chain: cross-reactive Id-EM.
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Tian L, Shi MM, Forman HJ. Increased transcription of the regulatory subunit of gamma-glutamylcysteine synthetase in rat lung epithelial L2 cells exposed to oxidative stress or glutathione depletion. Arch Biochem Biophys 1997; 342:126-33. [PMID: 9185621 DOI: 10.1006/abbi.1997.9997] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
gamma-Glutamylcysteine synthetase (GCS) is the initial and rate-limiting enzyme in the glutathione (GSH) de novo synthesis pathway. GCS is composed of a heavy (73-kDa) catalytic subunit and a light (30-kDa) regulatory subunit, which maintains the Km for glutamate near physiologic concentrations. Previous studies have shown that the steady-state mRNA level and gene transcription for the catalytic subunit increased in response to the redox-cycling quinone 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) in rat lung epithelial L2 cells (M. M. Shi, et al., 1994, J. Biol. Chem. 269,26512-26517). The ratio of the catalytic to regulatory subunit mRNAs varies among tissues, and the anticancer drug cisplatin appears to induce only the catalytic subunit, suggesting independent gene regulation of the two subunits. Nonetheless, the present study found that the steady-state mRNA level and the transcription rate of the GCS regulatory subunit also increased under DMNQ-induced oxidative stress. Changes in mRNA followed a pattern similar to that for the catalytic subunit. The mRNA levels of the two subunits of GCS also both increased above the baseline levels in cells treated with BSO, an inhibitor of GCS enzymatic activity. These data suggest that, under conditions of oxidative stress or glutathione depletion, the regulatory subunit is upregulated at the level of mRNA transcription. Along with the elevation of the catalytic subunit, this increase in GCS regulatory subunit transcription contributes to increases in GCS enzymatic activity and cellular GSH content.
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Wang M, Stepkowski SM, Tian L, Langowski J, Yu J, Kloc M, Kahan BD. Nucleotide sequences of rat cDNA clones coding heavy chain class I major histocompatibility complex proteins. Transplant Proc 1997; 29:1661-2. [PMID: 9142222 DOI: 10.1016/s0041-1345(97)00005-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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356
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Stepkowski SM, Wang M, Langowski J, Ghobrial R, Qu X, Yu J, Tian L, Kahan BD. Localization of tolerogenic epitopes in the alpha 1 helical region of the rat class I major histocompatibility complex molecule. Transplant Proc 1997; 29:1663-4. [PMID: 9142223 DOI: 10.1016/s0041-1345(97)00006-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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357
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Vázquez-Abad D, Tian L, Monteón V, Zanetti M, Rothfield NF. CRI-EM is a human idiotype highly specific for scleroderma. Ann N Y Acad Sci 1997; 815:512-5. [PMID: 9186713 DOI: 10.1111/j.1749-6632.1997.tb52118.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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358
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Stepkowski SM, Tian L, Napoli KL, Ghobrial R, Wang ME, Chou TC, Kahan BD. Synergistic mechanisms by which sirolimus and cyclosporin inhibit rat heart and kidney allograft rejection. Clin Exp Immunol 1997; 108:63-8. [PMID: 9097913 PMCID: PMC1904622 DOI: 10.1046/j.1365-2249.1997.d01-984.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The studies presented herein examined the mechanism(s) whereby sirolimus (SRL) and cyclosporin (CsA) act synergistically to block allograft rejection. Combination index (CI = 1 reflects additive, CI > 1 antagonistic, and CI < 1 synergistic, effects) analysis documented potent synergism between SRL and CsA to block allograft rejection. Combinations of the two drugs produced synergistic prolongation of heart (CI = 0.001-0.2) or kidney (CI = 0.03-0.5) allograft survival at SRL/CsA ratios ranging from 1:12.5 to 1:200. Pharmacokinetic analysis of the individual drugs showed that CsA does not affect the blood levels of SRL, and SRL mildly increases the levels of CsA in SRL/CsA-treated rats. Quantitative polymerase chain reaction analysis was used to document that both subtherapeutic (1.0 mg/kg) and therapeutic (2.0 or 4.0 mg/kg) CsA doses inhibited the expression of interferon-gamma (IFN-gamma) (P < 0.03) and IL-2 (P < 0.003) mRNA produced by T helper (Th) 1 cells, as well as IL-10 (P < 0.001), but not IL-4 (NS) mRNA produced by Th2 cells. Contrariwise, all tested SRL doses (0.02, 0.04 or 0.08 mg/kg) did not affect cytokine mRNA expression. However, heart allografts from rat recipients treated with synergistic SRL/CsA doses displayed reduced levels of IFN-gamma (P < 0.01), IL-2 (P < 0.001) and IL-10 (P < 0.001) mRNA. Thus, because subtherapeutic doses of CsA reduce Th1/Th2 activity, thereby facilitating the inhibition of signal transduction by low does of SRL, the two agents act synergistically to inhibit allograft rejection.
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359
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Katz SM, Tian L, Stepkowski SM, Phan T, Bennett CF, Kahan BD. Effect of ICAM-1/LFA-1 blockade on pancreatic islet allograft survival, function, and early cytokine production. Transplant Proc 1997; 29:748-9. [PMID: 9123508 DOI: 10.1016/s0041-1345(96)00451-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Blood Glucose/metabolism
- Cytokines/biosynthesis
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/therapy
- Graft Survival/drug effects
- Intercellular Adhesion Molecule-1/immunology
- Intercellular Adhesion Molecule-1/physiology
- Islets of Langerhans Transplantation/immunology
- Islets of Langerhans Transplantation/physiology
- Kidney/immunology
- Lymphocyte Function-Associated Antigen-1/immunology
- Lymphocyte Function-Associated Antigen-1/physiology
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Oligonucleotides, Antisense/pharmacology
- RNA, Messenger/biosynthesis
- Transcription, Genetic
- Transplantation, Homologous
- Transplantation, Isogeneic
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360
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Wang M, Yu J, Wang ME, Tian L, Stepkowski SM, Kahan BD. Induction of donor-specific tolerance by chimeric class I MHC molecules bearing donor alpha 1 helical amino acids. Transplant Proc 1997; 29:1224-5. [PMID: 9123284 DOI: 10.1016/s0041-1345(96)00641-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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361
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Tian L, Yoshihara Y, Mizuno T, Mori K, Gahmberg CG. The neuronal glycoprotein telencephalin is a cellular ligand for the CD11a/CD18 leukocyte integrin. THE JOURNAL OF IMMUNOLOGY 1997. [DOI: 10.4049/jimmunol.158.2.928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Many leukocyte functions depend on interactions between the leukocyte-specific beta2 integrins CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs). Telencephalin (TLN) is a novel member of the Ig superfamily expressed in the central nervous system. The NH2-terminal five Ig-like domains of TLN show the highest homology with the Ig domains of ICAM-1, ICAM-2, ICAM-3, and LW (ICAM-4), the known cellular ligands for CD11a/CD18. Here, we demonstrate that TLN interacts with CD11a/CD18. Peripheral blood T cells, Jurkat T cells, and B lymphoblastoid cells bound to immunopurified recombinant human TLN proteins. This adhesion was through CD11a/CD18 and was significantly inhibited by an Ab to CD11a/CD18. Reciprocally, TLN-transfected L cells also bound to purified CD11a/CD18. Recombinant TLN proteins comprising either the first five Ig domains (TLN(1-5)) or the entire extracellular portion (TLN(1-9)) showed binding to CD11a/CD18. We conclude that TLN is a novel neuronal cell adhesion molecule that may be important in integrin-mediated cell-cell interactions in the central nervous system, and that the CD11a/CD18-dependent recognition site of human TLN is located within the NH2-terminal five domains of this molecule.
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362
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Tian L, Yoshihara Y, Mizuno T, Mori K, Gahmberg CG. The neuronal glycoprotein telencephalin is a cellular ligand for the CD11a/CD18 leukocyte integrin. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1997; 158:928-36. [PMID: 8993013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Many leukocyte functions depend on interactions between the leukocyte-specific beta2 integrins CD11/CD18 and their ligands, the intercellular adhesion molecules (ICAMs). Telencephalin (TLN) is a novel member of the Ig superfamily expressed in the central nervous system. The NH2-terminal five Ig-like domains of TLN show the highest homology with the Ig domains of ICAM-1, ICAM-2, ICAM-3, and LW (ICAM-4), the known cellular ligands for CD11a/CD18. Here, we demonstrate that TLN interacts with CD11a/CD18. Peripheral blood T cells, Jurkat T cells, and B lymphoblastoid cells bound to immunopurified recombinant human TLN proteins. This adhesion was through CD11a/CD18 and was significantly inhibited by an Ab to CD11a/CD18. Reciprocally, TLN-transfected L cells also bound to purified CD11a/CD18. Recombinant TLN proteins comprising either the first five Ig domains (TLN(1-5)) or the entire extracellular portion (TLN(1-9)) showed binding to CD11a/CD18. We conclude that TLN is a novel neuronal cell adhesion molecule that may be important in integrin-mediated cell-cell interactions in the central nervous system, and that the CD11a/CD18-dependent recognition site of human TLN is located within the NH2-terminal five domains of this molecule.
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363
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Tian L, Lawrence DA. Metal-induced modulation of nitric oxide production in vitro by murine macrophages: lead, nickel, and cobalt utilize different mechanisms. Toxicol Appl Pharmacol 1996; 141:540-7. [PMID: 8975779 DOI: 10.1006/taap.1996.0320] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Macrophages (M phi) can be induced to produce nitric oxide (NO), which has been suggested to be important for macrophages to exercise various functions. We have previously reported that an environmental toxicant, lead (Pb), can significantly inhibit NO production by murine splenic M phis. Herein, eight additional metal ions, gold (Au), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), and zinc (Zn), were assessed. In addition to Pb, Hg and Cd significantly suppressed NO production by cytokine (interferon-gamma and tumor necrosis factor-alpha)-stimulated murine M phis. Au and Cu also were inhibitory, but less than Pb, Hg, and Cd. In contrast, Cr and Zn were not modulatory, and Ni and Co significantly enhanced NO production by cytokine-stimulated M phis. The enhancement by Ni and Co was inhibited by the arginine analog N-monomethylarginine. The metals showed different activating/inhibiting profiles when added to a cell-free (activated M phi lysate) NO-producing-system in which inducible NO synthase (iNOS) is already expressed. Cr, Cu, Pb, and Zn moderately suppressed iNOS, which suggests that they may directly modify enzyme or cofactor activity. Cd, Hg, Mg, Ni, or Co did not produce any significant effect on NO production by the cell-free system. Inhibition of NO production by Pb-exposed M phis was not due to decreased expression of iNOS nor limited to its modest direct inhibition of iNOS; thus, other mechanism(s) must be accountable for the efficient Pb-induced inhibition of NO production by M phi. Ni or Co did induce a substantial increase of iNOS protein. Overall, these observations provide additional insight into the means by which metals via inhibition or enhancement of NO production may be pathogenic, by suppression of defense mechanisms or induction of hypersensitivity, respectively.
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364
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Wang M, Stepkowski SM, Tian L, Langowski JL, Hebert JS, Kloc M, Yu J, Kahan BD. Nucleotide sequences of three distinct cDNA clones coding for the rat class I heavy chain RT1n antigen. Immunogenetics 1996; 45:73-5. [PMID: 8881041 DOI: 10.1007/s002510050170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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365
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He G, Wang M, Xu H, Tian L, Yu J, Stepkowski SM, Kahan BD. Impact of different forms of recipient antigen and different routes of antigen administration in donor pretreatment for preventing graft-versus-host disease in rat small bowel transplantation. Transplant Proc 1996; 28:2469. [PMID: 8907906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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366
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Cai Q, Tian L, Wei H. Age-dependent increase of indigenous DNA adducts in rat brain is associated with a lipid peroxidation product. Exp Gerontol 1996; 31:373-85. [PMID: 9415120 DOI: 10.1016/0531-5565(95)02027-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Indigenous DNA adducts (I-compounds) are considered to be a biomarker of aging tissues. Thus far, few studies have been conducted to investigate the accumulation patterns of I-compounds in the brain during aging. Particularly, identities of age-dependent I-compounds have largely remained unknown. In the current study, we have determined the amounts of I-compounds in the brains of male Fischer 344 rats at ages 1, 6, 12, 18, and 24 months using a 32P-postlabeling technique. The results indicate that I-compounds increase in the rat brain age dependently from 6 to 24 months of age. Total I-adduct levels (central and upper cutouts) increase 3.5-fold from 6 to 24 months. Contrary to the results of other investigators, brains of 1-month-old rats contain the highest level of I-compounds, which may be due to the hypermetabolic status during the infant period. In an effort to characterize I-compounds, different deoxynucleosides were coincubated with malondialdehyde (MDA). The results show that only deoxyguanosine (dGMP)-MDA adducts overlap with I-compounds of the rat brain DNA adducts map. A total of five dGMP-MDA adducts have been identified as responsible for I-compounds in brain tissues. It is known that brain tissue contains high levels of lipids that are susceptible to oxygen free radicals and that MDA is the most abundant and genotoxic product of lipid peroxidation. The present study provides supporting evidence that lipid peroxidation and its product (MDA) may play an important role in endogenous brain DNA modification, which may partly contribute to cerebral aging and age-related degenerative disorders of the brain. The accumulation of I-compounds with aging may serve as an index of indirect oxidative damage to DNA as evidenced by the presence of MDA-DNA adducts.
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367
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Tian L, Chen WF. [CD4-CD8- to CD4-CD8+ transition induced by anti-CD3 mAb in vitro cell culture system]. SHI YAN SHENG WU XUE BAO 1996; 29:39-47. [PMID: 9208641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In our experiments, we have observed the effect of anti-CD3 mAb in inducing the differentiation of CD4-CD8- (double negative, DN) thymocytes into CD4+ CD8+ (double positive, DP) cells in an in vitro cell culture system including IL-7 for maintaining the growth of TN thymocytes. When TN thymocytes were stimulated by immobilized anti-CD3 mAb for 3 days, CD4-CD8+ cells generated, which were mostly immediate precursors of CD4+CD8+ thymocytes according to their surface TCR beta expression. The transition from DN to DP thymocytes accompanied with downregulation of interleukin 2 receptor (IL-2 R) alpha chain, and the TCR alpha beta-CD3 expression induced by IL-7 was also inhibited. Anti-CD3 mAb was effective only before the appearance of functional TCR-alpha beta-CD3 complex. Taking together, the results strongly suggest that anti-CD3 mAb induced DN thymocyte defferentiation is through the pre-TCR complex.
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368
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Wang M, Stepkowski SM, Wang ME, Tian L, Qu X, Tu Y, He G, Kahan BD. Induction of specific allograft immunity by soluble class I MHC heavy chain protein produced in a baculovirus expression system. Transplantation 1996; 61:448-57. [PMID: 8610360 DOI: 10.1097/00007890-199602150-00024] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Spodoptera frugiperda (Sf9) insect cells secreted a class I MHC RT1.Aa heavy chain protein when infected with baculovirus that bore a construct that contained a honeybee melittin secretion (ms) signal attached to RT1.Aa cDNA. The RT1.Aa heavy chain protein in the culture supernatant and cell lysate immunoprecipitated in the presence of 5 individual anti-RT1.Aa-specific mAb. As was revealed by densitometric analysis, the ms signal increased the production (7- to 17-fold) and secretion (20- to 47-fold) of RT1.Aa protein by Sf9 cells (compared with RT1Aa-Sf9 cells without the ms signal). Subcutaneous immunization with secreted RT1.Aa heavy chain protein of Wistar-Furth (WF; RT1u) rats (day -4) accelerated the rejection of ACI (RT1a), but not third-party Brown Norway (BN; RT1n), heart allografts from 5.9 +/- 0.5 days in controls to 4.0 +/- 0.0 days (P < 0.001); cell lysate from RT1.Aa-Sf9 or ms/RT1.Aa-Sf9 cells reduced ACI heart allograft survival to 3.8 +/- 0.4 days or 3.7 +/- 0.5 days, respectively (P < 0.001). Indirect presentation of RT1.Aa heavy chain proteins by syngeneic macrophages shortened the survival of RT1.Aa-disparate PVG.R8 (RT1.AaDuBuCu) heart allografts in PVG.1U (RT1u) hosts from 6.3 +/- 0.5 days in controls to 4.0 +/- 0.0 days (P < 0.01). Finally, RT1.Aa heavy chain proteins injected into the thymus or into the portal vein (day -14) in combination with anti-T cell receptor mAb (days -14 and -13) induced indefinite survival of ACI liver allografts in Lewis (RT1l) recipients ( > 250 days). Thus, indirect presentation of soluble class I MHC heavy chain proteins (produced in a baculovirus/Sf9 cell system) may either sensitize or induce tolerance in the same fashion as native class I MHC alloantigens expressed on donor tissues.
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369
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Wang M, Stepkowski SM, Tian L, Langowski JL, Yu J, Kahan BD. Nucleotide sequences of three distinct clones coding for rat heavy chain class I major histocompatibility antigens. Immunogenetics 1996; 43:318-20. [PMID: 9110936 DOI: 10.1007/bf02441000] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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370
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Prior C, Tian L, el Mallah AI, Young L, Ward JM. Neuromuscular blocking profile of the vecuronium analogue, Org-9487, in the rat isolated hemidiaphragm preparation. Br J Pharmacol 1995; 116:3049-55. [PMID: 8680742 PMCID: PMC1909232 DOI: 10.1111/j.1476-5381.1995.tb15962.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The neuromuscular effects of the short-acting aminosteroid muscle relaxant Org-9487 have been studied in the in vitro rat phrenic nerve/hemidiaphragm preparation by use of twitch tension and electrophysiological recording techniques. 2. Org-9487 (5-100 microM) produced a concentration-dependent decrease in the amplitude of twitches (0.1 Hz) and tetanic contractions (50 Hz) evoked by motor nerve stimulation. The compound produced fade of force during both 50 Hz stimulation and train-of-four stimulation at 2 Hz, indicating a prejunctional component of action. 3. Anticholinesterases only partially reversed the effect of Org-9487 on twitch responses. This was possibly because, at the concentrations required to block twitches in the rat, Org-9487 itself was found to possess significant anticholinesterase activity. 4. Org-9487 (3 microM) increased the rundown of endplate current amplitudes during a 2 s train of 50 Hz nerve stimulation. This was because Org-9487 increased the quantal content of the first endplate current in the train without affecting acetylcholine release towards the latter part of the train. 5. Org-9487 (10 microM) produced a voltage-dependent decrease in the time constant of decay of endplate currents at 32 degrees C and 0.5 Hz, indicative of a block of endplate ion channels. The blocking rate constant increased with membrane hyperpolarization.
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371
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Abstract
The vesicular hypothesis of quantal acetylcholine release describes the process by which discrete packages (or quanta) of the transmitter are released from nerve terminals through the exocytosis of the content of synaptic vesicles. However, cholinergic synaptic vesicles can no longer be vaguely regarded as simple membrane bound 'sacks' of the transmitter. Modern molecular, biochemical, morphological and electrophysiological research has revealed them to be complex cellular structures with a heterogeneous mixture of functions. Thus, not all synaptic vesicle populations are formed under the same circumstances and there are variations in the releasability of synaptic vesicle populations. This review briefly outlines some of the experimental research that has lead to our current thinking on the heterogeneity of vesicular acetylcholine storage in cholinergic nerve terminals. In addition, a model for vesicular acetylcholine storage and release is presented that attempts to accommodate many of the modern ideas concerning cholinergic synaptic vesicle function and interaction.
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372
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Tian L, Cai Q, Bowen R, Wei H. Effects of caloric restriction on age-related oxidative modifications of macromolecules and lymphocyte proliferation in rats. Free Radic Biol Med 1995; 19:859-65. [PMID: 8582660 DOI: 10.1016/0891-5849(95)00090-k] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Decreased immune function associated with aging has been demonstrated in both humans and animals. We hypothesize that reactive oxygen species (ROS)-mediated damage to biological macromolecules may contribute to compromised immune response during aging. In this study, we compared the levels of lipid peroxidation and oxidatively modified proteins in plasma and splenocytes, and the mitogen-induced T lymphocyte proliferation in ad lib-fed (AL) and caloric restricted (CR) Fischer 344 x BNF1 male rats at the ages of 5, 18, and 31 months. The results show that AL rats exhibit an age-related decrease in proliferative response of splenic lymphocytes to phytohemagglutinin (PHA) and concanavalin A (Con A). This functional decline in T-lymphocytes during aging is inversely correlated to the levels of both lipid peroxidation and protein carbonyl in the plasma and splenic lymphocytes. Caloric restriction, however, can partially reverse the age-dependent decrease in T lymphocyte proliferation and significantly reduce lipid peroxidation and protein carbonyl contents in plasma and splenocytes. The above observations support the hypothesis that the age-associated declines in immune function are related to the oxidative modification of biological macromolecules, which in turn may lead to enzyme inactivation, membrane disruption, and cell senescence. One of the mechanisms by which caloric restriction reverses declined immune function in aged rats is hypothesized to be through reduction in ROS production and thereby protection of cellular macromolecules against oxidative damage.
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373
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Charpentier G, Belloncik S, Ducros G, Fontenille D, Tian L, Quiot JM. Establishment and characterization of three cell lines from Aedes triseriatus (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 1995; 32:793-800. [PMID: 8551501 DOI: 10.1093/jmedent/32.6.793] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three cell lines (A.t. GRIP-1, 2, and 3) were established from Aedes triseriatus (Say) embryonated eggs or neonate larvae and their morphology, growth, karyotype, and isozyme pattern were studied. The isozyme alleles observed in the 3 cell lines also were found in adults of the original mosquito colony. Each cell line differed in enzymatic, morphological, and karyotypical patterns. La Crosse encephalitis (LAC) and snowshoe hare (SSH) viruses, members of the California encephalitis virus group, were able to replicate in these 3 cell lines. Furthermore, these cell lines, especially A.t. GRIP-1, were more sensitive than the Aedes aegypti (L.) (ATC 10) cell line for detection of small amounts of delta-endotoxin of Bacillus thuringiensis serovar. israelensis (de Barjac).
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374
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Prior C, Tian L, Dempster J, Marshall IG. Prejunctional actions of muscle relaxants: synaptic vesicles and transmitter mobilization as sites of action. GENERAL PHARMACOLOGY 1995; 26:659-66. [PMID: 7635241 DOI: 10.1016/0306-3623(94)00246-j] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. Nicotinic antagonists such as tubocurarine affect acetylcholine release from motor nerve terminals at the neuromuscular junction. 2. Electrophysiological studies comparing the prejunctional actions of tubocurarine to those of vesamicol and vecuronium have been used to provide an insight into the mechanisms involved in the prejunctional effects of tubocurarine-like compounds. 3. The observed prejunctional actions of tubocurarine can be accounted for by a model in which the compound has two separately identifiable effects on the nerve terminal. At low frequencies of nerve stimulation tubocurarine augments acetylcholine release while at high frequencies of nerve stimulation tubocurarine depresses acetylcholine release. 4. Both of the effects of tubocurarine on acetylcholine release are a consequence of a change in the number of quanta within the nerve terminal immediately available for release upon nerve stimulation. 5. On the basis of our experimental observations, we suggest that the two prejunctional effects of tubocurarine are mediated through two pharmacologically distinct prejunctional nAChRs.
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375
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Tian L, Chen WF. [Role of IL-7 on early thymocyte development]. SHENG LI KE XUE JIN ZHAN [PROGRESS IN PHYSIOLOGY] 1995; 26:249-52. [PMID: 8584895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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