901
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Jiang D, Zheng L, Lenardo MJ. Caspases in T-cell receptor-induced thymocyte apoptosis. Cell Death Differ 1999; 6:402-11. [PMID: 10381640 DOI: 10.1038/sj.cdd.4400513] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Apoptosis eliminates inappropriate or autoreactive T lymphocytes during thymic development. Intracellular mediators involved in T-cell receptor (TCR)-mediated apoptosis in developing thymocytes during negative selection are therefore of great interest. Caspases, cysteine proteases that mediate mature T-cell apoptosis, have been implicated in thymocyte cell death, but their regulation is not understood. We examined caspase activities in distinct thymocyte subpopulations that represent different stages of T-cell development. We found caspase activity in CD4+CD8+ double positive (DP) thymocytes, where selection involving apoptosis occurs. Earlier and later thymocyte stages exhibited no caspase activity. Only certain caspases, such as caspase-3 and caspase-8-like proteases, but not caspase-1, are active in DP thymocytes in vivo and can be activated when DP thymocytes are induced to undergo apoptosis in vitro by TCR-crosslinking. Thus, specific caspases appear to be developmentally regulated in thymocytes.
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902
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Dudley E, Hornung F, Zheng L, Scherer D, Ballard D, Lenardo M. NF-kappaB regulates Fas/APO-1/CD95- and TCR- mediated apoptosis of T lymphocytes. Eur J Immunol 1999. [PMID: 10092091 DOI: 10.1002/(sici)1521-4141(199903)29:03<878::aid-immu878>3.0.co;2-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The maintenance of lymphocyte homeostasis by apoptosis is a critical regulatory mechanism in the normal immune system. The transcription factor NF-kappaB has been shown to play a role in protecting cells against death mediated by TNF We show here that NF-kappaB also has a role in regulating Fas/APO-1/CD95-mediated death, a major pathway of peripheral T cell death. Transfection of Jurkat cells with the NF-kappaB subunits p50 and p65 confers resistance against Fas-mediated apoptosis. Reciprocally, inhibition of NF-kappaB activation by a soluble peptide inhibitor or a dominant form of the NF-kappaB inhibitor, IkappaB, makes the cells more susceptible to Fas-mediated apoptosis. Furthermore, inhibition of NF-kappaB activation by a soluble peptide inhibitor rendered a T cell hybridoma more susceptible to TCR-mediated apoptosis. Correspondingly, transfection of p50 and p65 provided considerable protection from TCR-mediated apoptosis. These observations were corroborated by studies on Fas-mediated death in primary T cells. Concanavalin A-activated cycling T cell blasts from mice that are transgenic for the dominant IkappaB molecule have increased sensitivity to Fas-mediated apoptosis, associated with a down-regulation of NF-kappaB complexes in the nucleus. In addition, blocking TNF, itself a positive regulator of NF-kappaB, with neutralizing antibodies renders the cells more susceptible to anti-Fas-mediated apoptosis. In summary, our results provide compelling evidence that NF-kappaB protects against Fas-mediated death and is likely to be an important regulator of T cell homeostasis and tolerance.
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903
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Martin DA, Zheng L, Siegel RM, Huang B, Fisher GH, Wang J, Jackson CE, Puck JM, Dale J, Straus SE, Peter ME, Krammer PH, Fesik S, Lenardo MJ. Defective CD95/APO-1/Fas signal complex formation in the human autoimmune lymphoproliferative syndrome, type Ia. Proc Natl Acad Sci U S A 1999; 96:4552-7. [PMID: 10200300 PMCID: PMC16370 DOI: 10.1073/pnas.96.8.4552] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Heterozygous mutations in the CD95 (APO-1/Fas) receptor occur in most individuals with autoimmune lymphoproliferative syndrome (ALPS) and dominantly interfere with apoptosis by an unknown mechanism. We show that local or global alterations in the structure of the cytoplasmic death domain from nine independent ALPS CD95 death-domain mutations result in a failure to bind the FADD/MORT1 signaling protein. Despite heterozygosity for the abnormal allele, lymphocytes from ALPS patients showed markedly decreased FADD association and a loss of caspase recruitment and activation after CD95 crosslinking. These data suggest that intracytoplasmic CD95 mutations in ALPS impair apoptosis chiefly by disrupting death-domain interactions with the signaling protein FADD/MORT1.
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904
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Zheng L, Liu S, Deng L, Zhang Q. [Using the method of two-color fluorescence in situ hybridization to detect aneuploidy of human sperms]. ZHONGHUA YI XUE YI CHUAN XUE ZA ZHI = ZHONGHUA YIXUE YICHUANXUE ZAZHI = CHINESE JOURNAL OF MEDICAL GENETICS 1999; 16:116-8. [PMID: 10194261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVE To develop the method of two-color fluorescence in situ hybridization (FISH) assay and use it for detecting the aneuploidy frequency of human sperm chromosome. METHODS Sperm sample was washed three times and the slides were prepared. The sperm heads were decondensed with dithiothreitol (DTT) and lithium diiodosalicylate (LIS). Then, the sperm nuclei were hybridized with biotin labeled alpha satellite X chromosome DNA probe (DXZ1) and digoxigenin labeled alpha satellite Y chromosome DNA probe (DYZ3). The hybridization signals were detected with CY3-Streptavidin, goat antistrepavidin for biotin labeled probe and with mouse antidigoxigenin, rabbit antimouse-FITC for digoxigenin labeled probe. RESULTS Under the Nikon fluorescence microscope, the hybridization signals in the sperm heads were clearly visible. The sperm with one red hybridization signal was X chromosome sperm (X sperm), and the sperm with one green hybridization signal in the sperm head was Y chromosome sperm (Y sperm). In the case of two hybridization signals in one sperm head, the sperm should be a numerical abnormal one. By using two color FISH with one euchromosome probe and one sex chromosome probe, the sperm with same color of two hybridization signals in one sperm head could be identified as aneuploidy sperm or diploid sperm. CONCLUSION The two color FISH assay may be used to detect the aneuploidy frequency of human sperms that were exposed to mutagents and environmental potential aneuoploidogenic agents.
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905
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Zheng L, Szaniszlo PJ. Cloning and use of the WdURA5 gene as a hisG cassette selection marker for potentially disrupting multiple genes in Wangiella dermatitidis. Med Mycol 1999. [DOI: 10.1046/j.1365-280x.1999.00196.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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906
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Zheng L, Szaniszlo PJ. Cloning and use of the WdURA5 gene as a hisG cassette selection marker for potentially disrupting multiple genes in Wangiella dermatitidis. Med Mycol 1999; 37:85-96. [PMID: 10361263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
A genomic clone encoding the Wangiella dermatitidis orotidine monophosphate pyrophosphorylase gene (WdURA5) was isolated by screening a subgenomic plasmid DNA library of this phaeohyphomycotic agent using a PCR amplification product of the gene as a probe. When plasmid DNA containing the cloned WdURA5 gene was introduced by electroporation into a wdura5 auxotrophic recipient strain derived previously by selection with 5-fluoroorotic acid (5-FOA), an apparent gene repair event occurred at high frequency without any evidence of integration of the plasmid DNA. Therefore, the hygromycin B resistance gene (the hph gene) was used as a dominant selective marker for the disruption of WdURA5 to generate a new, more stable, wdura5 auxotrophic strain. Transformation of this strain was then achieved with high efficiency and high frequency by site-specific integration using WdURA5 as a selective marker. To initiate attempts to use this marker repeatedly for multiple chitin synthase (WdCHS) gene disruptions in single strains of W. dermatitidis, a hisG_WdURA5_hisG cassette was constructed and used to disrupt WdCHS2. The WdURA5 gene in the disruptant was then successfully recycled under selection for resistance to 5-FOA.
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907
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Li Y, Zheng L. [Effect of non-uniform heating of ordinary microwave oven upon the determination results of sample digested in the oven]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 1999; 19:253-255. [PMID: 15819026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article studies the heating variation of the sample placed on various relative positions of the turning tray in the microwave oven cavity. We find the distribution regularity of heating points that are of insignificant variation statistically, and determine Cu content in the sample GBW07233 and Cu and As contents in the sample NIES SRM No. 1 that are digested on these points. The determinations prove that the precision and accuracy of the determination results will not reduce, even though there are insignificant variations of temperature on these points.
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908
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Zheng L, Orsida BE, Ward C, Wilson JW, Williams TJ, Walters EH, Snell GI. Airway vascular changes in lung allograft recipients. J Heart Lung Transplant 1999; 18:231-8. [PMID: 10328149 DOI: 10.1016/s1053-2498(98)00035-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
BACKGROUND In asthma there has been increasing interest in the contribution of airway microvasculature to airway wall thickness and lumenal narrowing. Post-lung transplant, the survival of the donor airway is generally dependent on mixed-venous blood flow from pulmonary artery collaterals associated with the discontinuation of the bronchial circulation. This may lead to an altered vasculature of the airways post transplant, which may contribute to airflow limitation. METHODS Endobronchial biopsies were taken from the lower lobe sub-carinae in 22 lung transplant recipients (LTR), 8 with Bronchiolitis Obliterans Syndrome (BOS), 14 without, and 14 controls. Seven microm frozen sections were stained for type IV collagen with a monoclonal antibody, using an indirect immunoperoxidase method. Bronchial vessels were identified by typical staining of type IV collagen in the true basement membrane supporting the endothelium. The number of vessels per mm2 of submucosa to a depth of 150 microm below the basement membrane, the percent vascularity and average vessel size were quantified using a computerised image analyser. RESULTS Compared to the controls, a higher percent vascularity was found in LTR both with and without BOS (p < 0.05). In the BOS group, the percent best FEV1.0 decreased exponentially, in association with increased airway vessel size (r2 = 0.67, p = 0.01). CONCLUSIONS These findings suggest that increased airway vascularity is a feature of the allograft airways post transplant. This may be a result of the relative hypoxia and hypercarbia in the blood supplying the airways from the pulmonary artery collaterals or of the chronic inflammatory process in the airways. These changes in vascularity could contribute to airflow limitation in BOS.
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909
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Dudley E, Hornung F, Zheng L, Scherer D, Ballard D, Lenardo M. NF-kappaB regulates Fas/APO-1/CD95- and TCR- mediated apoptosis of T lymphocytes. Eur J Immunol 1999; 29:878-86. [PMID: 10092091 DOI: 10.1002/(sici)1521-4141(199903)29:03<878::aid-immu878>3.0.co;2-9] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The maintenance of lymphocyte homeostasis by apoptosis is a critical regulatory mechanism in the normal immune system. The transcription factor NF-kappaB has been shown to play a role in protecting cells against death mediated by TNF We show here that NF-kappaB also has a role in regulating Fas/APO-1/CD95-mediated death, a major pathway of peripheral T cell death. Transfection of Jurkat cells with the NF-kappaB subunits p50 and p65 confers resistance against Fas-mediated apoptosis. Reciprocally, inhibition of NF-kappaB activation by a soluble peptide inhibitor or a dominant form of the NF-kappaB inhibitor, IkappaB, makes the cells more susceptible to Fas-mediated apoptosis. Furthermore, inhibition of NF-kappaB activation by a soluble peptide inhibitor rendered a T cell hybridoma more susceptible to TCR-mediated apoptosis. Correspondingly, transfection of p50 and p65 provided considerable protection from TCR-mediated apoptosis. These observations were corroborated by studies on Fas-mediated death in primary T cells. Concanavalin A-activated cycling T cell blasts from mice that are transgenic for the dominant IkappaB molecule have increased sensitivity to Fas-mediated apoptosis, associated with a down-regulation of NF-kappaB complexes in the nucleus. In addition, blocking TNF, itself a positive regulator of NF-kappaB, with neutralizing antibodies renders the cells more susceptible to anti-Fas-mediated apoptosis. In summary, our results provide compelling evidence that NF-kappaB protects against Fas-mediated death and is likely to be an important regulator of T cell homeostasis and tolerance.
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910
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Zhou D, Shen Y, Chalifoux L, Lee-Parritz D, Simon M, Sehgal PK, Zheng L, Halloran M, Chen ZW. Mycobacterium bovis bacille Calmette-Guérin enhances pathogenicity of simian immunodeficiency virus infection and accelerates progression to AIDS in macaques: a role of persistent T cell activation in AIDS pathogenesis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1999; 162:2204-16. [PMID: 9973496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
It has recently been proposed that Mycobacterium tuberculosis may enhance the pathogenicity of HIV infections and accelerate the course of HIV disease. This hypothesis has been tested in the present study using a simian immunodeficiency virus of macaques (SIVmac)/Mycobacterium bovis bacille Calmette-Guérin (BCG)-coinfected macaque model. Naive and chronically SIVmac-infected monkeys were evaluated. Following BCG inoculation, the SIVmac-infected monkeys exhibited the dominant responses of TCR-beta complementarity-determining region 3-restricted T cell subpopulations. This BCG-driven T cell activation correlated with a marked increase in viral loads in SIVmac-infected monkeys. Moreover, the prolonged T cell activation coincided with the enhanced decline of CD4+ PBL counts and the accelerated progression to clinical AIDS in the coinfected monkeys, suggesting that Mycobacterium-driven T cell activation may be the mechanism underlying the enhanced pathogenicity of AIDS virus infection in the coinfected individuals. Within 2 to 7 mo after BCG coinfection, all chronically SIVmac-infected monkeys died from SIV-induced AIDS including tuberculosis-like disease. Surprisingly, the naive monkeys manifested a T cell activation-related toxic shock syndrome and a profound depletion of CD4+ lymphocytes 2 wk after simultaneous SIVmac/BCG inoculation. These naive animals died 2 mo after SIVmac/BCG inoculation, with the evidence of the persistent SIV p27 antigenemia and SIVmac-induced disease. In contrast, the normal monkeys not infected with SIVmac survived BCG infection; the control SIVmac-infected animals showed a natural course of chronic SIV infection. Thus, results from this SIV/BCG coinfection model strongly support the hypothesis that active coinfection with HIV and Mycobacterium can impact remarkably on the AIDS virus-induced disease.
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911
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Marques LJ, Zheng L, Poulakis N, Guzman J, Costabel U. Pentoxifylline inhibits TNF-alpha production from human alveolar macrophages. Am J Respir Crit Care Med 1999; 159:508-11. [PMID: 9927365 DOI: 10.1164/ajrccm.159.2.9804085] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is an important proinflammatory cytokine. Recently, pentoxifylline (POF) has been shown to suppress the synthesis of TNF-alpha from lipopolysaccharide (LPS)-stimulated human monocytes in cell cultures and in vivo. The aim of this study was to investigate whether POF-induced suppression of TNF-alpha secretion affects peripheral blood monocytes (PBM) and alveolar macrophages (AM) equally, and whether POF is able to suppress the spontaneous TNF-alpha production from AM in pulmonary sarcoidosis in vitro. In seven patients without interstitial lung disease we studied the effect of POF on LPS-stimulated PBM and AM cultured for 24 h. In six patients with sarcoidosis we investigated the effect of POF on the enhanced spontaneous TNF-alpha production by AM in vitro. POF induced a dose-dependent suppression of the LPS-stimulated TNF-alpha production which was not different for PBM and AM, respectively. In sarcoidosis, POF inhibited the spontaneous TNF-alpha production of AM at 0.1 mM by 91% and at 1 mM by 98%. In conclusion, POF inhibits LPS-induced TNF-alpha production from PBM and AM to a similar extent and can also inhibit the exaggerated spontaneous TNF-alpha production from AM in sarcoidosis in vitro. This may be the basis for further clinical trials to evaluate POF as an immunotherapeutic agent in sarcoidosis.
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912
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Yu JJ, Zheng L, Thomas PW, Szaniszlo PJ, Cole GT. Isolation and confirmation of function of the Coccidioides immitis URA5 (orotate phosphoribosyl transferase) gene. Gene 1999; 226:233-42. [PMID: 9931494 DOI: 10.1016/s0378-1119(98)00556-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The OPRTase (URA5) gene of the human pathogenic fungus, Coccidioides immitis (Ci), was cloned, sequenced, chromosome-mapped and expressed both by transformation of Escherichia coli and by complementation of wdura5Delta, an auxotrophic strain of Wangiella dermatitidis (Wd) with a disrupted URA5 gene. A functional assay of the recombinant URA5 expressed by E. coli was conducted to ensure that the isolated Ci gene encodes the appropriate enzyme. In the absence of a transformation system for Ci, we also used a reported method of introduction of heterologous DNA into cells of the phylogenetically related fungus, Wangiella dermatitidis, to confirm the function of the Ci URA5 gene. Both the genomic and cDNA sequences of the Ci URA5 gene are presented. The transcription start point and two poly(A) addition sites were confirmed. The gene contains a 714-bp ORF that translates a 238-amino-acid (aa) protein of 25.5kDa and pI of 6.5. No introns are present. The translated protein contains a single, putative N-glycosylation site. The deduced Ci protein showed 55-63% aa sequence similarity to reported fungal OPRTases. The URA5 gene was mapped to chromosome IV of Ci, and was shown to be a single copy gene by Southern and Northern hybridizations. Transformation of the wdura5Delta mutant to prototrophy was accomplished by electroporation of Wd yeast cells with the Ci URA5 gene. Cellular uptake of the heterologous DNA was confirmed by Southern hybridization. The stable transformants were unable to grow on a medium containing 5-FOA. Expression of the Ci URA5 gene can be used as a selectable marker for a transformation system, and the latter is essential for molecular studies of this pathogenic fungus.
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913
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Pittman RN, Golub AS, Popel AS, Zheng L. Interpretation of phosphorescence quenching measurements made in the presence of oxygen gradients. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 454:375-83. [PMID: 9889914 DOI: 10.1007/978-1-4615-4863-8_45] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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914
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Zheng L, Szaniszlo P. Cloning and use of theWdURA5gene as ahisGcassette selection marker for potentially disrupting multiple genes inWangiella dermatitidis. Med Mycol 1999. [DOI: 10.1080/02681219980000141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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915
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Sugg SL, Ezzat S, Zheng L, Freeman JL, Rosen IB, Asa SL. Oncogene profile of papillary thyroid carcinoma. Surgery 1999; 125:46-52. [PMID: 9889797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
BACKGROUND Our purpose was to study the expression of multiple oncogenes in papillary thyroid cancer for possible interactions and prognostic significance. METHODS Twenty papillary thyroid carcinomas were studied for expression/mutation of 3 oncogenes: ras, ret/PTC, and erbB-2/neu. H, N, and K ras codons were examined by polymerase chain reaction (PCR), single-stranded conformation polymorphism, and sequencing. The thyroid oncogene ret/PTC was identified by reverse transcription (RT)-PCR. Gene amplification of erbB-2/neu was analyzed by differential PCR. The transmembrane domain of erbB-2/neu was sequenced for activating mutations. Quantitation of erbB-2/neu mRNA was evaluated by competitive RT-PCR, and protein expression was determined by immunohistochemistry. RESULTS Among 20 tumors, 3 had insular/anaplastic dedifferentiation, 13 were intrathyroidal, and 7 were metastatic to cervical lymph nodes (6) or lung (1). An H-ras 13 mutation was found in 1 metastatic tumor and an N-ras 61 mutation in 1 intrathyroidal tumor. ret/PTC was identified in 3 intrathyroidal and 5 metastatic tumors. No erbB-2/neu DNA amplification or mutations were identified, although 4 tumors had elevated erbB-2/neu mRNA levels. Three of 20 patients had abnormalities detected in multiple oncogenes; 2 had elevated erbB-2/neu mRNA and ret/PTC rearrangements, and 1 of these had pulmonary metastasis. An intrathyroidal papillary cancer had an N61 ras mutation and a ret/PTC gene rearrangement. CONCLUSIONS ret/PTC rearrangements are present in 40% of papillary thyroid carcinomas and may play a role in metastatic behavior. In contrast, ras mutations are rare (10%). erbB-2/neu gene amplification and activating mutations are not detected, although elevated mRNA levels were found in 20% of papillary carcinomas. The lack of correlation among the 3 oncogenes in 17 of 20 (85%) papillary thyroid carcinomas suggests that they were not cumulative factors in the pathogenesis of these tumors.
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916
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Low KB, Ittensohn M, Le T, Platt J, Sodi S, Amoss M, Ash O, Carmichael E, Chakraborty A, Fischer J, Lin SL, Luo X, Miller SI, Zheng L, King I, Pawelek JM, Bermudes D. Lipid A mutant Salmonella with suppressed virulence and TNFalpha induction retain tumor-targeting in vivo. Nat Biotechnol 1999; 17:37-41. [PMID: 9920266 DOI: 10.1038/5205] [Citation(s) in RCA: 329] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Systemically administered tumor-targeted Salmonella has been developed as an anticancer agent, although its use could be limited by the potential induction of tumor necrosis factor alpha (TNFalpha)-mediated septic shock stimulated by lipid A. Genetic modifications of tumor-targeting Salmonella that alter lipid A and increase safety must, however, retain the useful properties of this bacteria. We report here that disruption of the Salmonella msbB gene reduces TNFalpha induction and increases the LD50 of this pathogenic bacteria by 10,000-fold. Notwithstanding this enormous difference, Salmonella retains its tumor-targeting properties, exhibiting tumor accumulation ratios in excess of 1000:1 compared with normal tissues. Administration of this bacteria to mice bearing melanoma results in tumors that are less than 6% the size of tumors in untreated controls at day 18. Thus, the antitumor activity previously demonstrated using tumor-targeting Salmonella with normal lipid A is retained. Lipid modification of tumor-specific bacterial vectors provides a means for reducing septic shock and further suggests that the antitumor activity of these bacteria may be independent of TNFalpha.
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917
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Zheng L, Zomerdijk TP, Van Den Barselaar MT, Geertsma MF, Van Furth R, Nibbering PH. Arachidonic acid, but not its metabolites, is essential for FcgammaR-stimulated intracellular killing of Staphylococcus aureus by human monocytes. Immunology 1999; 96:90-7. [PMID: 10233682 PMCID: PMC2326709 DOI: 10.1046/j.1365-2567.1999.00664.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since arachidonic acid (AA) production by phospholipase A2 (PLA2) is essential for the Fcgamma receptor (FcgammaR)-mediated respiratory burst and phagocytosis of opsonized erythrocytes by monocytes and macrophages, we focused in this study on the role of AA and its metabolites in the FcgammaR-stimulated intracellular killing of Staphylococcus aureus by human monocytes. The results revealed that the PLA2 inhibitors, but not inhibitors of cyclo-oxygenase and lipoxygenase, markedly suppressed the FcgammaR-mediated killing process. The production of O-2 by monocytes upon FcgammaR cross-linking was inhibited by 4-bromophenacyl bromide in a dose-dependent fashion, indicating that inhibition of PLA2 activity impairs the oxygen-dependent bactericidal mechanisms of monocytes, which could be partially restored by addition of exogenous AA and docosahexaenoic acid, but not myristic acid. These polyunsaturated fatty acids, but not myristic acid, stimulated the intracellular killing of S. aureus by monocytes, although not as effectively as FcgammaR cross-linking. Furthermore, FcgammaR cross-linking stimulated the release of AA from monocytes. Studies with selective inhibitors revealed that the FcgammaR-mediated activation of PLA2 is dependent on Ca2+ and tyrosine kinase activity. Together these results indicate a key role for PLA2/AA, but not its major metabolites, in mediating the FcgammaR-stimulated intracellular killing of S. aureus by monocytes.
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918
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Wang R, Kafatos FC, Zheng L. Microsatellite markers and genotyping procedures for Anopheles gambiae. PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:33-7. [PMID: 10234176 DOI: 10.1016/s0169-4758(98)01360-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The procedures outlined in this article by Rui Wang, Fotis Kafatos and Liangbiao Zheng are well suited to studies of field mosquito populations, and also to the genetic mapping of qualitative and quantitative traits of Anopheles gambiae, a major malaria vector in Africa. An accurate, reproducible and high-throughput microsatellite genotyping procedure has been established.
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919
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Zheng L, Grishin AM, Rao KV. Epitaxial growth and electrical properties of PCLT thin films for IR detector sensor. ACTA ACUST UNITED AC 1998. [DOI: 10.1051/jp4:1998925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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920
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Edelmann L, Zheng L, Wang ZF, Marzluff W, Wessel GM, Childs G. The TATA binding protein in the sea urchin embryo is maternally derived. Dev Biol 1998; 204:293-304. [PMID: 9851860 DOI: 10.1006/dbio.1998.9052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cDNA encoding the TATA binding protein was isolated from 8- to 16-cell and morula-stage embryonic libraries of two distantly related species of sea urchin, Strongylocentrotus purpuratus and Lytechinus variegatus, respectively. The two proteins are 96% identical over both the N- and C-terminal domains, suggesting a conservation of transcriptional processes between the two species. The prevalence of SpTBP transcripts at several developmental time points was determined using the tracer excess titration method, and the corresponding number of TBP protein molecules was determined by quantitative Western blot analysis. Our results indicate that the amount of TBP mRNA and protein per embryo remains relatively constant throughout development. An initial large pool of TBP protein (>10(9)) molecules in the egg becomes diluted as a consequence of cell division and decreases to about 2 x 10(6) molecules per cell by the gastrula stage. We found by in situ RNA hybridization that the oocyte contains a large amount of TBP mRNA which is depleted late in oogenesis so that the eggs and early embryos have extremely low levels of TBP mRNA. We conclude that the oocyte manufactures nearly all of the TBP protein necessary for embryogenesis.
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921
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Stríz I, Pokorná H, Zheng L, Guzman J, Costabel U. Different expression of integrins by mononuclear phagocytes in peripheral blood and bronchoalveolar lavage fluid. Respir Med 1998; 92:1326-30. [PMID: 10197225 DOI: 10.1016/s0954-6111(98)90137-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alveolar macrophages (AM) originate from blood monocytes and, during the maturation process, undergo functional and morphological changes which are also reflected in their phenotypic pattern. Among the macrophage membrane antigens, adhesion molecules of the integrin family are particularly important for effector functions and cell-cell interactions. The aim of this study was to analyse the membrane expression of selected integrins by AM recovered from bronchoalveolar lavage (BAL) as compared to their precursors, peripheral blood monocytes (PBM). The cells were stained using a sensitive immunoperoxidase assay with 10 different monoclonal antibodies. The data showed a higher expression by AM than PBM of all but one of the studied adhesion molecules. The only exception was CD11b (Mac-1, CR3) which showed a higher expression in PBM than in AM. Several molecules, for example, CD49d (VLA-4), CD51 (vitronectin receptor), and CD54 (intercellular adhesion molecule-1, ICAM-1) were found to be upregulated by AM in patients with a lymphocytic pattern of BAL. In contrast, the phenotype of PBM does not show any changes in these patients. In conclusion, we have demonstrated differences in the expression of integrins between AM and PBM which can be partially responsible for some of their functional differences.
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922
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Lou J, Gasche Y, Zheng L, Critico B, Monso-Hinard C, Juillard P, Morel P, Buurman WA, Grau GE. Differential reactivity of brain microvascular endothelial cells to TNF reflects the genetic susceptibility to cerebral malaria. Eur J Immunol 1998; 28:3989-4000. [PMID: 9862335 DOI: 10.1002/(sici)1521-4141(199812)28:12<3989::aid-immu3989>3.0.co;2-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Upon infection with Plasmodium berghei ANKA (PbA), various inbred strains of mice exhibit different susceptibility to the development of cerebral malaria (CM). Tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN-gamma) have been shown to be crucial mediators in the pathogenesis of this neurovascular complication. Brain microvascular endothelial cells (MVEC) represent an important target of both cytokines. In the present study, we show that brain MVEC purified from CM-susceptible (CM-S) CBA/J mice and CM-resistant (CM-R) BALB/c mice exhibit a different sensitivity to TNF. CBA/J brain MVEC displayed a higher capacity to produce IL-6 and to up-regulate intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in response to TNF than BALB/c brain MVEC. In contrast, no difference was found in the induction of E-selectin after TNF challenge. CM-S brain MVEC were also significantly more sensitive to TNF-induced lysis. This differential reactivity to TNF was further substantiated by comparing TNF receptor expression on CM-S and CM-R brain MVEC. Although the constitutive expression of TNF receptors was comparable on cells from the two origins, TNF induced an up-regulation of both p55 and p75 TNF receptors in CM-S, but not in CM-R brain MVEC. A similar regulation was found at the level of TNF receptor mRNA, but not for receptor shedding. Although a protein kinase C inhibitor blocked the response to TNF in both the brain MVEC, an inhibitor of protein kinase A selectively abolished the response to TNF in CM-R, but not CM-S brain MVEC, suggesting a differential protein kinase involvement in TNF-induced activation of CM-S and CM-R brain MVEC. These results indicate that brain MVEC purified from CM-S and CM-R mice exhibit distinctive sensitivity to TNF This difference may be partly due to a differential regulation of TNF receptors and via distinct protein kinase pathways.
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923
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Lanzaro GC, Touré YT, Carnahan J, Zheng L, Dolo G, Traoré S, Petrarca V, Vernick KD, Taylor CE. Complexities in the genetic structure of Anopheles gambiae populations in west Africa as revealed by microsatellite DNA analysis. Proc Natl Acad Sci U S A 1998; 95:14260-5. [PMID: 9826688 PMCID: PMC24361 DOI: 10.1073/pnas.95.24.14260] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/1998] [Indexed: 11/18/2022] Open
Abstract
Chromosomal forms of Anopheles gambiae, given the informal designations Bamako, Mopti, and Savannah, have been recognized by the presence or absence of four paracentric inversions on chromosome 2. Studies of karyotype frequencies at sites where the forms occur in sympatry have led to the suggestion that these forms represent species. We conducted a study of the genetic structure of populations of An. gambiae from two villages in Mali, west Africa. Populations at each site were composed of the Bamako and Mopti forms and the sibling species, Anopheles arabiensis. Karyotypes were determined for each individual mosquito and genotypes at 21 microsatellite loci determined. A number of the microsatellites have been physically mapped to polytene chromosomes, making it possible to select loci based on their position relative to the inversions used to define forms. We found that the chromosomal forms differ at all loci on chromosome 2, but there were few differences for loci on other chromosomes. Geographic variation was small. Gene flow appears to vary among different regions within the genome, being lowest on chromosome 2, probably due to hitchhiking with the inversions. We conclude that the majority of observed genetic divergence between chromosomal forms can be explained by forces that need not involve reproductive isolation, although reproductive isolation is not ruled out. We found low levels of gene flow between the sibling species Anopheles gambiae and Anopheles arabiensis, similar to estimates based on observed frequencies of hybrid karyotypes in natural populations.
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924
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Sugg SL, Ezzat S, Zheng L, Rosen IB, Freeman JL, Asa SL. Cytoplasmic staining of erbB-2 but not mRNA levels correlates with differentiation in human thyroid neoplasia. Clin Endocrinol (Oxf) 1998; 49:629-37. [PMID: 10197079 DOI: 10.1046/j.1365-2265.1998.00580.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Amplification and overexpression of the erbB-2 proto-oncogene in human carcinomas may have prognostic significance. Its role in thyroid carcinoma is controversial. We investigated human thyroid tumours for erbB-2 gene amplification, activating mutations in the transmembrane domain, quantitative mRNA expression and protein expression. MATERIALS AND METHODS DNA and mRNA were extracted from 47 morphologically characterized, frozen thyroid tumours including 10 nodular hyperplasias, 3 follicular carcinomas and 34 papillary carcinomas (4 with tall-cell features, 2 with insular and 2 with anaplastic de-differentiation). DNA amplification was analysed by differential PCR. The transmembrane domain of erbB-2 was sequenced in all tumours for activating mutations in position 659. Levels of mRNA expression were determined by competitive mRNA RT-PCR. Immunohistochemistry (IHC) for erbB-2 protein expression in corresponding paraffin-embedded samples was evaluated. RESULTS Our results showed no DNA amplification of erbB-2. Sequencing of the transmembrane domain of erbB-2 revealed no activating mutations. The level of mRNA expression was variable, 11 papillary carcinomas showing statistically significant elevated mRNA levels compared with corresponding normal thyroid tissue; however, this did not correlate with other indicators of poor prognosis. In contrast to elevated mRNA levels in tumours, the level of protein staining correlated with degree of differentiation, normal and hyperplastic tissue being strongly positive and poorly differentiated tumours negative. CONCLUSION There are no mutations or amplifications of the erbB-2 gene in human thyroid tumours. Elevated erbB-2 mRNA expression in some thyroid tumours is not associated with clinical features of poor prognosis; however, the significance of the elevated mRNA levels is unclear, as it did not result in protein overexpression. Instead, cytoplasmic erbB-2 protein detection by IHC correlates with differentiation of human thyroid tumours and may be a feature of good prognosis.
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925
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Martin DA, Combadiere B, Hornung F, Jiang D, McFarland H, Siegel R, Trageser C, Wang J, Zheng L, Lenardo MJ. Molecular genetic studies in lymphocyte apoptosis and human autoimmunity. NOVARTIS FOUNDATION SYMPOSIUM 1998; 215:73-82; discussion 82-91. [PMID: 9760572 DOI: 10.1002/9780470515525.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Using a genetic approach, we have studied the molecular basis of human autoimmunity with special emphasis on a disease that is due to defective lymphocyte apoptosis. Recently, we and our collaborators have found that the autoimmune/lymphoproliferative syndrome (ALPS), an inherited disease of children comprising marked lymphoid hyperplasia and autoimmune manifestations, is due to abnormalities in the CD95 gene that cause defective lymphocyte apoptosis. Our recent investigations have shown that the mutations in most families with ALPS cause either global or local changes in the structure of a cytoplasmic portion of the molecule called the 'death domain'. These death domain alterations impair binding of the adapter protein FADD/MORT1 and result in a failure to activate apoptotic caspases after CD95 (Fas/APO-1) cross-linking. Mutations in apoptotic caspases may also contribute to the pathogenesis of ALPS in individuals that have no CD95 gene mutations.
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926
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Bartles JR, Zheng L, Li A, Wierda A, Chen B. Small espin: a third actin-bundling protein and potential forked protein ortholog in brush border microvilli. J Cell Biol 1998; 143:107-19. [PMID: 9763424 PMCID: PMC2132824 DOI: 10.1083/jcb.143.1.107] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/1998] [Revised: 08/27/1998] [Indexed: 11/22/2022] Open
Abstract
An approximately 30-kD isoform of the actin-binding/ bundling protein espin has been discovered in the brush borders of absorptive epithelial cells in rat intestine and kidney. Small espin is identical in sequence to the COOH terminus of the larger ( approximately 110-kD) espin isoform identified in the actin bundles of Sertoli cell-spermatid junctional plaques (Bartles, J.R., A. Wierda, and L. Zheng. 1996. J. Cell Sci. 109:1229-1239), but it contains two unique peptides at its NH2 terminus. Small espin was localized to the parallel actin bundles of brush border microvilli, resisted extraction with Triton X-100, and accumulated in the brush border during enterocyte differentiation/migration along the crypt-villus axis in adults. In transfected BHK fibroblasts, green fluorescent protein-small espin decorated F-actin-containing fibers and appeared to elicit their accumulation and/or bundling. Recombinant small espin bound to skeletal muscle and nonmuscle F-actin with high affinity (Kd = 150 and 50 nM) and cross-linked the filaments into bundles. Sedimentation, gel filtration, and circular dichroism analyses suggested that recombinant small espin was a monomer with an asymmetrical shape and a high percentage of alpha-helix. Deletion mutagenesis suggested that small espin contained two actin-binding sites in its COOH-terminal 116-amino acid peptide and that the NH2-terminal half of its forked homology peptide was necessary for bundling activity.
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927
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Zheng L, Hu L, Chen X. [Salvia Miltiorrhizae Composita in preventing PaO2 lowering induced by controlled hypotension with nitroglycerin]. ZHONGGUO ZHONG XI YI JIE HE ZA ZHI ZHONGGUO ZHONGXIYI JIEHE ZAZHI = CHINESE JOURNAL OF INTEGRATED TRADITIONAL AND WESTERN MEDICINE 1998; 18:598-600. [PMID: 11477842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To observe the effects of Salvia Miltiorrhizae Composita (SMC) on blood gas variations of nitroglycerin (NTG) controlled hypotension. METHODS Sixteen patients who were arranged to undergo operation under general anesthesia in controlled hypotension condition were divided randomly into control group (n = 8) and SMC group (treated group, n = 8), NTG were used to create controlled hypotension in both groups and blood pressure decrease about 30% comparing with the control values. Patients in the treated group were administered intravenously with SMC (16 ml) before the utilization of NTG. RESULTS Significant PaO2 decrease and Pa-etCO2 increase were observed in the control group during the controlled hypotension period. However, blood gas values in the treated group did not evidently change. CONCLUSION It suggested that SMC can prevent the side effects of NTG on blood gas.
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928
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Ward C, Snell GI, Zheng L, Orsida B, Whitford H, Williams TJ, Walters EH. Endobronchial biopsy and bronchoalveolar lavage in stable lung transplant recipients and chronic rejection. Am J Respir Crit Care Med 1998; 158:84-91. [PMID: 9655711 DOI: 10.1164/ajrccm.158.1.9707117] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We have obtained endobronchial biopsies (EBB), bronchoalveolar lavage (BAL), and transbronchial biopsies (TBB) in 17 stable lung transplant recipients (sLTR), 8 subjects with physiologic evidence of chronic rejection (BOS), and 9 normal subjects. A striking finding was the marked neutrophilia in BAL samples from patients with BOS, in the carefully screened absence of infection. A statistically higher neutrophil count was also present in the sLTR group relative to the normal group. Median BAL neutrophil count in BOS was 100 x 10(3)/ml, range 13-1,661 10(3)/ml (p < 0.001 relative to normal subjects and sLTR). Median BAL neutrophil count in sLTR was 7 x 10(3)/ml, range 1-81 10(3)/ml (p < 0.01 relative to normal subjects). Normal subjects had a median BAL neutrophil count of 3 x 10(3)/ml, range 1-7 10(3)/ml. There was evidence of a predominance of CD8 lymphocytes in BAL from sLTR and BOS with a lower CD4/CD8 ratio in both compared to normal subjects (p < 0.05). EBB mononuclear cell counts, class II major histocompatibility complex expression, and T-cell activation markers were normal in BOS, in contrast to the sLTR group. Our data may be consistent with BOS, representing a relative resolution of an active mononuclear cell chronic inflammation, perhaps at the expense of airway fibrosis. The relevance of the BAL neutrophilia and its role in BOS pathogenesis need further longitudinal investigation.
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929
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Silverman DH, Hoh CK, Seltzer MA, Schiepers C, Cuan GS, Gambhir SS, Zheng L, Czernin J, Phelps ME. Evaluating tumor biology and oncological disease with positron-emission tomography. Semin Radiat Oncol 1998; 8:183-96. [PMID: 9634495 DOI: 10.1016/s1053-4296(98)80044-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The usefulness of positron-emission tomography (PET) for noninvasive assessment of several biological parameters of neoplastic tissue has been reviewed. Numerous radiotracers have been developed, whose particular distribution in the presence of cancer in vivo serves to distinguish medically relevant properties of the tumor cells with which they associate. That distribution is most accurately determined through use of a PET scanner, to localize and quantify the tracer molecules, in which have been incorporated positron-emitting isotopes. These tracers include hypoxia markers, receptor ligands, substrates for enzymatic modification by the products of expression of specific genes, and precursors of protein anabolism and carbohydrate catabolism. In addition, application of PET to evaluation of patients with some particular cancers has been examined, while placing special emphasis on the level of scientific rigor of the evidence underlying conclusions about appropriate use of PET in oncology.
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930
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Zheng L, Yang F, Ye D. [Location of cochlear defect by AR spectrum analysis of TEOAE]. ZHONGGUO YI LIAO QI XIE ZA ZHI = CHINESE JOURNAL OF MEDICAL INSTRUMENTATION 1998; 22:187-191. [PMID: 12016821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new method is proposed in this paper to locate the position of hearing loss (high frequency, middle frequency or low frequency). The method is based on AR spectrum analysis of the transient evoked oto acoustic emission (TEOAE). The results obtained are essentially the same as those obtained by DPGRAM, which comes from DPOAE. Thus, a new field of TEOAE application is found by the proposed method.
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931
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Siegel RM, Martin DA, Zheng L, Ng SY, Bertin J, Cohen J, Lenardo MJ. Death-effector filaments: novel cytoplasmic structures that recruit caspases and trigger apoptosis. J Cell Biol 1998; 141:1243-53. [PMID: 9606215 PMCID: PMC2137190 DOI: 10.1083/jcb.141.5.1243] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The death-effector domain (DED) is a critical protein interaction domain that recruits caspases into complexes with members of the TNF-receptor superfamily. Apoptosis can also be induced by expressing certain DED-containing proteins without surface receptor cross-linking. Using Green Fluorescent Protein to examine DED-containing proteins in living cells, we show that these proteins cause apoptosis by forming novel cytoplasmic filaments that recruit and activate pro-caspase zymogens. Formation of these filaments, which we term death-effector filaments, was blocked by coexpression of viral antiapoptotic DED-containing proteins, but not by bcl-2 family proteins. Thus, formation of death-effector filaments allows a regulated intracellular assembly of apoptosis-signaling complexes that can initiate or amplify apoptotic stimuli independently of receptors at the plasma membrane.
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932
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Zheng L, Cash VL, Flint DH, Dean DR. Assembly of iron-sulfur clusters. Identification of an iscSUA-hscBA-fdx gene cluster from Azotobacter vinelandii. J Biol Chem 1998; 273:13264-72. [PMID: 9582371 DOI: 10.1074/jbc.273.21.13264] [Citation(s) in RCA: 485] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An enzyme having the same L-cysteine desulfurization activity previously described for the NifS protein was purified from a strain of Azotobacter vinelandii deleted for the nifS gene. This protein was designated IscS to indicate its proposed role in iron-sulfur cluster assembly. Like NifS, IscS is a pyridoxal-phosphate containing homodimer. Information gained from microsequencing of oligopeptides obtained by tryptic digestion of purified IscS was used to design a strategy for isolation and DNA sequence analysis of a 7,886-base pair A. vinelandii genomic segment that includes the iscS gene. The iscS gene is contained within a gene cluster that includes homologs to nifU and another gene contained within the major nif cluster of A. vinelandii previously designated orf6. These genes have been designated iscU and iscA, respectively. Information available from complete genome sequences of Escherichia coli and Hemophilus influenzae reveals that they also encode iscSUA gene clusters. A wide conservation of iscSUA genes in nature and evidence that NifU and NifS participate in the mobilization of iron and sulfur for nitrogenase-specific iron-sulfur cluster formation suggest that the products of the iscSUA genes could play a general role in the formation or repair of iron-sulfur clusters. The proposal that IscS is involved in mobilization of sulfur for iron-sulfur cluster formation in A. vinelandii is supported by the presence of a cysE-like homolog in another gene cluster located immediately upstream from the one containing the iscSUA genes. O-Acetylserine synthase is the product of the cysE gene, and it catalyzes the rate-limiting step in cysteine biosynthesis. A similar cysE-like gene is also located within the nif gene cluster of A. vinelandii. The likely role of such cysE-like gene products is to increase the cysteine pool needed for iron-sulfur cluster formation. Another feature of the iscSUA gene cluster region from A. vinelandii is that E. coli genes previously designated as hscB, hscA, and fdx are located immediately downstream from, and are probably co-transcribed with, the iscSUA genes. The hscB, hscA, and fdx genes are also located adjacent to the iscSUA genes in both E. coli and H. influenzae. The E. coli hscA and hscB gene products have previously been shown to bear primary sequence identity when respectively compared with the dnaK and dnaJ gene products and have been proposed to be members of a heat-shock-cognate molecular chaperone system of unknown function. The close proximity and apparent co-expression of iscSUA and hscBA in A. vinelandii indicate that the proposed chaperone function of the hscBA gene products could be related to the maturation of iron-sulfur cluster-containing proteins. Attempts to place non-polar insertion mutations within either A. vinelandii iscS or hscA revealed that such mutations could not be stably maintained in the absence of the corresponding wild-type allele. These results reveal a very strong selective pressure against the maintenance of A. vinelandii iscS or hscA knock-out mutations and suggest that such mutations are either lethal or highly deleterious. In contrast to iscS or hscA, a strain having a polar insertion mutation within the cysE-like gene was readily isolated and could be stably maintained. These results show that the cysE-like gene located upstream from iscS is not essential for cell growth and that the cysE-like gene and the iscSUA-hscBA-fdx genes are contained within separate transcription units.
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933
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Zhao S, Molnar G, Zhang J, Zheng L, Averboukh L, Pardee AB. 3'-end cDNA pool suitable for differential display from a small number of cells. Biotechniques 1998; 24:842-50, 852. [PMID: 9591137 DOI: 10.2144/98245rr01] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have generated a 3' cDNA pool from the RNA of only 1000 or fewer cells by reverse transcription (RT) from an extended oligo(dT) primer with a 3' degenerate base and a second strand primer with four degenerate 3' bases, followed by PCR. Reproducible differential displays (DD) can be made from this essentially inexhaustible source of DNA. The method produced DD patterns that are comparable but not identical in band number and size distribution with those obtained by the original RT-DD technique. Northern blots performed with the excised bands verified altered gene expressions. The data indicate that this 3'-end cDNA pool can supplement current PCR-based methods of expression genetics. This pool of cDNA sequences also provides a reliable source for primer-specific gene amplifications.
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934
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Eberstadt M, Huang B, Chen Z, Meadows RP, Ng SC, Zheng L, Lenardo MJ, Fesik SW. NMR structure and mutagenesis of the FADD (Mort1) death-effector domain. Nature 1998; 392:941-5. [PMID: 9582077 DOI: 10.1038/31972] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
When activated, membrane-bound receptors for Fas and tumour-necrosis factor initiate programmed cell death by recruiting the death domain of the adaptor protein FADD to the membrane. FADD then activates caspase 8 (also known as FLICE or MACH) through an interaction between the death-effector domains of FADD and caspase 8. This ultimately leads to the apoptotic response. Death-effector domains and homologous protein modules known as caspase-recruitment domains have been found in several proteins and are important regulators of caspase (FLICE) activity and of apoptosis. Here we describe the solution structure of a soluble, biologically active mutant of the FADD death-effector domain. The structure consists of six antiparallel, amphipathic alpha-helices and resembles the overall fold of the death domains of Fas and p75. Despite this structural similarity, mutations that inhibit protein-protein interactions involving the Fas death domain have no effect when introduced into the FADD death-effector domain. Instead, a hydrophobic region of the FADD death-effector domain that is not present in the death domains is vital for binding to FLICE and for apoptotic activity.
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935
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Zheng L, Hogue CW, Brennan JD. Effects of metal binding affinity on the chemical and thermal stability of site-directed mutants of rat oncomodulin. Biophys Chem 1998; 71:157-72. [PMID: 9648206 DOI: 10.1016/s0301-4622(98)00096-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Tryptophan fluorescence was used to study the stability and unfolding behavior of several single tryptophan mutants of the metal-binding protein rat oncomodulin (OM); F102W, Y57W, Y65W and the engineered protein CDOM33 which had the 12 residues of the CD loop replaced with a more potent metal binding site. Both the thermal and the chemical stability were improved upon binding of metal ions with the order apo < Ca2+ < Tb3+. During thermal denaturation, the transition midpoints (T(un)) of Y65W was the lowest, followed by Y57W and F102W. The placement of the Trp residue in the F-helix in F102W made the protein slightly more thermostable, although the fluorescence response was readily affected by chemical denaturants, which acted through the disruption of hydrogen bonds at the C-terminal end of the F-helix. Under both thermal and chemical denaturation, the engineered protein showed the highest stability. This indicated that increasing the number of metal ligating oxygens in the binding site, either by using a metal ion with a higher coordinate number (i.e., Tb3+) which binds more carboxylate ligands, or by providing more ligating groups, as in the CDOM33 replacement, produces notable improvements in protein stability.
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936
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Zheng L, Zhang S, Xue W, Kapil S, Minocha HC. Expression of a 50 kDa putative receptor for bovine viral diarrhea virus in bovine fetal tissues. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 1998; 62:156-9. [PMID: 9553718 PMCID: PMC1189466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The expression of a 50 kDa bovine viral diarrhea virus putative receptor in different bovine fetal tissues from 3-month old fetuses was studied. The receptor expression was examined by immunocytochemical staining and by immunoblotting using antiidiotypic probe (anti-D89). Intense specific staining in enterocytes of the small and large intestines, cortical tubular epithelial cells of kidneys, respiratory epithelial cells of the trachea and esophageal mucosal epithelial cells was observed, demonstrating the strong expression of bovine viral diarrhea virus receptor in the tissues. Weak staining was found in cerebellum, thymus, spleen, liver, cerebrum, and lung tissues; however, heart tissues were negative. Immunoblotting results correlated with the immunoperoxidase staining assays. Thus, the expression levels of the receptor are variable in different tissues. This pattern of expression may provide clues to the pathogenic potential of bovine viral diarrhea virus in the bovine fetus.
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937
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Habib AA, Gulcher JR, Högnason T, Zheng L, Stefánsson K. The OMgp gene, a second growth suppressor within the NF1 gene. Oncogene 1998; 16:1525-31. [PMID: 9569019 DOI: 10.1038/sj.onc.1201683] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Oligodendrocyte-Myelin glycoprotein gene (OMgp) is placed within an intron of the NF1 gene. Neurofibromin, the product of NF1, acts as a RasGAP and suppresses growth; inactivating mutations in NF1 lead to neurofibromatosis type 1. We report that OMgp also has growth suppressive effects and downregulates mitogenic signaling pathways closely related to those influenced by neurofibromin. Overexpression of OMgp alters mitogenic signaling in NIH3T3 fibroblasts. Cells overexpressing OMgp grow more slowly in serum compared to controls and show a partial G1 block upon cell cycle analysis. PDGF is the primary mitogen for fibroblasts in serum. Overexpression of OMgp alters PDGF signaling in fibroblasts which results in a block of mitogenic signaling. PDGF induced activation of c-Src is blocked, as is the induction of c-Myc and c-Fos, while tyrosine phosphorylation of the PDGFbeta receptor, PLCgamma1 and induction of c-Jun are intact. Although a number of genes embedded within other genes have been described, the biological significance of this arrangement remains unknown. We demonstrate here that structurally unrelated products of two such genes may exercise closely related functions. Our data also raise the possibility of a role for OMgp in disorders of cell proliferation such as NF1.
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938
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Li R, Yu DS, Tanaka M, Zheng L, Berger SL, Stillman B. Activation of chromosomal DNA replication in Saccharomyces cerevisiae by acidic transcriptional activation domains. Mol Cell Biol 1998; 18:1296-302. [PMID: 9488444 PMCID: PMC108842 DOI: 10.1128/mcb.18.3.1296] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/1997] [Accepted: 12/09/1997] [Indexed: 02/06/2023] Open
Abstract
A large body of evidence from viral systems has established that transcription factors play an important and direct role in activating viral DNA replication. Among the transcriptional activation domains that can stimulate viral DNA replication are acidic domains such as those derived from herpes simplex virus VP16 and the tumor suppressor p53. Here we show that acidic activation domains can also activate a cellular origin of replication in a chromosomal context. When tethered to the yeast ARS1 (autonomously replicating sequence 1) origin of replication, both VP16 and p53 activation domains can enhance origin function. In addition, the C-terminal acidic region of the yeast transcription factor ABF1, which normally activates the ARS1 origin, is sufficient for activating ARS1 function when tethered to the origin. Mutations at residues Trp-53 and Phe-54 of a 20-residue (41 to 60) activation region of p53 abolish the activation of both replication and transcription, suggesting that the same structural determinants may be employed to activate both processes in yeast. Furthermore, using a two-dimensional gel electrophoresis method, we demonstrate that the GAL4-p53 chimeric activator can activate initiation of chromosomal replication from an origin inserted at the native ARS1 locus. These findings strongly suggest functional conservation of the mechanisms used by the acidic activation domains to activate viral DNA replication in mammalian cells and chromosomal replication in yeast.
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939
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Martin DA, Siegel RM, Zheng L, Lenardo MJ. Membrane oligomerization and cleavage activates the caspase-8 (FLICE/MACHalpha1) death signal. J Biol Chem 1998; 273:4345-9. [PMID: 9468483 DOI: 10.1074/jbc.273.8.4345] [Citation(s) in RCA: 294] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many forms of apoptosis, including that caused by the death receptor CD95/Fas/APO-1, depend on the activation of caspases, which are proteases that cleave specific intracellular proteins to cause orderly cellular disintegration. The requirements for activating these crucial enzymatic mediators of death are not well understood. Using molecular chimeras with either CD8 or Tac, we find that oligomerization at the cell membrane powerfully induces caspase-8 autoactivation and apoptosis. Death induction was abrogated by the z-VAD-fmk, z-IETD-fmk, or p35 enzyme inhibitors or by a mutation in the active site cysteine but was surprisingly unaffected by death inhibitor Bcl-2. Amino acid substitutions that prevent the proteolytic separation of the caspase from its membrane-associated domain completely blocked apoptosis. Thus, oligomerization at the membrane is sufficient for caspase-8 autoactivation, but apoptosis could involve a death signal conveyed by the proteolytic release of the enzyme into the cytoplasm.
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940
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Zheng L, Trageser CL, Willerford DM, Lenardo MJ. T cell growth cytokines cause the superinduction of molecules mediating antigen-induced T lymphocyte death. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1998; 160:763-9. [PMID: 9551911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
TCR stimulation of T lymphocytes that are activated and cycling in the presence of IL-2 leads to programmed cell death. We now show that this effect is at least partly attributable to the ability of IL-2 to dramatically increase the expression of mRNAs encoding ligands and receptors that mediate apoptosis. We also found that cyclosporin was not able to fully inhibit the TCR induction of death molecule mRNAs or TCR-induced apoptosis, although it could completely turn off IL-2 expression. The effect growth cytokines was further explored in T cells derived from mice bearing a homozygous deficiency of the IL-2R alpha-chain. We found that IL-2Ralpha-/- cells were resistant to death if IL-2 was used to induce apoptosis susceptibility, but that large amounts of other T cell growth cytokines, such as IL-4 and IL-7, could induce cell cycle progression and promote TCR-induced apoptosis. However, our findings suggest that autoimmunity and lymphoproliferation in IL-2Ralpha-/- mice can result from the loss of IL-2 stimulated feedback apoptosis and that other growth cytokines are not produced at levels sufficient to compensate for this deficit.
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941
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Wibo M, Feron O, Zheng L, Maleki M, Kolar F, Godfraind T. Thyroid status and postnatal changes in subsarcolemmal distribution and isoform expression of rat cardiac dihydropyridine receptors. Cardiovasc Res 1998; 37:151-9. [PMID: 9539869 DOI: 10.1016/s0008-6363(97)00228-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE The aim was to analyze the early postnatal changes in myocardial density, subsarcolemmal localization and isoform expression of dihydropyridine receptors in rat ventricle and the influence of thyroid status on these changes. METHODS Newborn rats were treated from postnatal day 2 with L-triiodothyronine (T3) or 6-n-propyl-2-thiouracil )PTU) and ventricles were collected on day 1, 7 and 14. Radioligand binding and cell fractionation (density gradient centrifugation) techniques were used to determine the tissue density of various receptors and their subcellular localization. To analyze dihydropyridine receptor alpha 1 subunit isoform expression, cDNA fragments corresponding to a large portion of motif IV were amplified by reverse transcriptase-polymerase chain reaction and treated with appropriate restriction endonucleases to determine the frequency of splicing events at the level of motif IV. RESULTS The myocardial density of dihydropyridine receptors increased 3-fold from day 1 to day 14 in control rats, and this increase occurred predominantly in membrane entities equilibrating at high densities in sucrose gradient, that is, presumably, in junctional structures (dyadic couplings). This maturation was delayed after PTU-treatment, and somewhat accelerated by excess T3. The proportion of mRNA variants typical of foetal heart (IVS3A variant and 'deleted' variant, showing a 33-nucleotide deletion at the level of the extracellular loop between IVS3 and IVS4) decreased with age in control rats. This reduction was delayed after treatment with PTU but was not influenced by excess T3. CONCLUSION Hypothyroidism impaired the early postnatal maturation of dihydropyridine receptors as regards both their concentration into junctional structures and the decrease in the relative expression of alpha 1-subunit mRNA variants typical of foetal heart.
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942
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Wilson DL, Carrillo A, Zheng L, Genc A, Duerk JL, Lewin JS. Evaluation of 3D image registration as applied to MR-guided thermal treatment of liver cancer. J Magn Reson Imaging 1998; 8:77-84. [PMID: 9500264 DOI: 10.1002/jmri.1880080117] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
There are many potential applications of three-dimensional (3D) image registration in MR-guided radiofrequency (RF) thermal ablation of tumors. For example, after registration of image volumes obtained before and after thermal ablation, a variety of quantitative and visual assessments of therapy were performed. For liver tumors, the accuracy of rigid body, manual registration on 19 pairs of image volumes was evaluated, almost all of which were obtained during thermal treatment sessions. Registration error was estimated as a distance between anatomical landmarks, including both internal vascular structures as well as the surface of the liver. Over all image pairs and throughout a large portion of the liver, the registration error was 3.1 mm (mean + 1 SD). From the bottom to the top of the liver, error increased on the order of 13%, probably because of liver motion and deformation resulting from respiration. Although probably insufficient for blind guidance of therapy, registration accuracy was undoubtedly sufficient for interesting applications in the planning, assessment, and optimization of interventional MR-guided thermal treatment of liver tumors.
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943
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Tian Q, Yu T, Zheng L, Tong Q, Tian G. [Study of spectrometer calibration experiment research]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 1997; 17:113-117. [PMID: 15810260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Spectrometer calibration is very important for quantitative research of imaging spectral remote sensing. After spectral calibtation and radiometric calibration, it was known that the average shift of wavelength of SE590 channels was 8nm, and the linear response was depended on the change of energy recieved by SE590, and spectral response resolution was unreasonable beyond 950nm range. At last, the calibration results were proved by the field experiment measurement data.
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944
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Chen S, Zheng L, Dean DR, Zalkin H. Role of NifS in maturation of glutamine phosphoribosylpyrophosphate amidotransferase. J Bacteriol 1997; 179:7587-90. [PMID: 9393728 PMCID: PMC179714 DOI: 10.1128/jb.179.23.7587-7590.1997] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Glutamine phosphoribosylpyrophosphate amidotransferase from Bacillus subtilis is synthesized as an inactive precursor that requires two maturation steps: incorporation of a [4Fe-4S] center and cleavage of an 11-residue NH2-terminal propeptide. Overproduction from a multicopy plasmid in Escherichia coli leads to the formation of soluble proenzyme and mature enzyme forms as well as a small fraction of insoluble proenzyme. Heterologous expression of Azotobacter vinelandii nifS from a compatible plasmid increased the maturation of the soluble proenzyme three- to fourfold without influencing the content of the insoluble fraction. These results support a role for NifS in heterologous Fe-S cluster assembly and enzyme maturation.
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945
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Ward C, Snell GI, Orsida B, Zheng L, Williams TJ, Walters EH. Airway versus transbronchial biopsy and BAL in lung transplant recipients: different but complementary. Eur Respir J 1997; 10:2876-80. [PMID: 9493677 DOI: 10.1183/09031936.97.10122876] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Lung transplantation is now an established therapeutic intervention for end-stage cardiopulmonary disease in humans. Chronic rejection, in the form of bronchiolitis obliterans syndrome (BOS), remains the commonest cause of morbidity and mortality in those surviving more than 3 months. The pathology of BOS involves airway changes. We have evaluated the potential for endobronchial biopsies (EBB) to complement existing sampling methods used in allograft monitoring and have compared the results of EBB findings with those of bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB) in 18 clinically stable patients. We found that all the EBB had inflammatory cells present but that only five TBB specimens had evidence of inflammation, with airway material being present in 78% of the TBB. Paired BAL and EBB yielded different results, with no correlations between total macrophages, lymphocytes, CD4+ cells or CD8+ cells. We conclude that endobronchial biopsies are potentially useful as an additional sample for the monitoring of inflammation in lung allografts, since they yield different, and potentially complimentary, information to bronchoalveolar lavage and transbronchial biopsy.
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946
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Fan Z, Huang XL, Zheng L, Wilson C, Borowski L, Liebmann J, Gupta P, Margolick J, Rinaldo C. Cultured blood dendritic cells retain HIV-1 antigen-presenting capacity for memory CTL during progressive HIV-1 infection. THE JOURNAL OF IMMUNOLOGY 1997. [DOI: 10.4049/jimmunol.159.10.4973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Dendritic cells (DC) are potent APC that may be involved in the pathogenesis of HIV-1 infection. We studied the APC function of DC from HIV-1-infected subjects that were derived from monocyte-depleted PBMC by culture in human IL-4 and human granulocyte-macrophage CSF. The cultured cells from the HIV-1-infected subjects had similar morphology and phenotype of mature DC (CD80 = 41 +/- 8%, CD86 = 77 +/- 5%, CD40 = 87 +/- 6%, CD1a = 1 +/- 1%) to DC cultured from seronegative subjects. The yield of these DC was lower than from HIV-1-seronegative subjects (4 +/- 0% vs 11 +/- 2%, p < 0.01), and the lower DC yields correlated with lower numbers of blood CD4+ T cells (r = 0.60, p < 0.01) and higher plasma viral load (r = -0.49, p < 0.01). DC from HIV-1-infected subjects were infected with recombinant vaccinia virus vectors expressing Gag, Pol, and Env and were able to stimulate equal or higher levels of MHC class I-restricted, anti-HIV-1 memory CTL (CTLm) than were similarly treated, autologous B lymphocyte cell lines. DC pulsed with peptides representing HIV-1 CTL epitopes stimulated higher levels of anti-HIV-1 CTLm responses than did DC infected with the vaccinia virus-HIV-1 constructs. Allogeneic, MHC class I-matched DC also stimulated anti-HIV-1 CTLm activity in cells from HIV-1-infected subjects. DC from early and late stages of HIV-1 infection had a similar ability to activate CTLm specific for targets expressing either HIV-1 genes via vaccinia virus vectors or HIV-1 immunodominant synthetic peptides. However, DC from either early or late stages of HIV-1 infection could not overcome the defect in anti-HIV-1 CTLm response in advanced infection.
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947
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Fan Z, Huang XL, Zheng L, Wilson C, Borowski L, Liebmann J, Gupta P, Margolick J, Rinaldo C. Cultured blood dendritic cells retain HIV-1 antigen-presenting capacity for memory CTL during progressive HIV-1 infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1997; 159:4973-82. [PMID: 9366424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dendritic cells (DC) are potent APC that may be involved in the pathogenesis of HIV-1 infection. We studied the APC function of DC from HIV-1-infected subjects that were derived from monocyte-depleted PBMC by culture in human IL-4 and human granulocyte-macrophage CSF. The cultured cells from the HIV-1-infected subjects had similar morphology and phenotype of mature DC (CD80 = 41 +/- 8%, CD86 = 77 +/- 5%, CD40 = 87 +/- 6%, CD1a = 1 +/- 1%) to DC cultured from seronegative subjects. The yield of these DC was lower than from HIV-1-seronegative subjects (4 +/- 0% vs 11 +/- 2%, p < 0.01), and the lower DC yields correlated with lower numbers of blood CD4+ T cells (r = 0.60, p < 0.01) and higher plasma viral load (r = -0.49, p < 0.01). DC from HIV-1-infected subjects were infected with recombinant vaccinia virus vectors expressing Gag, Pol, and Env and were able to stimulate equal or higher levels of MHC class I-restricted, anti-HIV-1 memory CTL (CTLm) than were similarly treated, autologous B lymphocyte cell lines. DC pulsed with peptides representing HIV-1 CTL epitopes stimulated higher levels of anti-HIV-1 CTLm responses than did DC infected with the vaccinia virus-HIV-1 constructs. Allogeneic, MHC class I-matched DC also stimulated anti-HIV-1 CTLm activity in cells from HIV-1-infected subjects. DC from early and late stages of HIV-1 infection had a similar ability to activate CTLm specific for targets expressing either HIV-1 genes via vaccinia virus vectors or HIV-1 immunodominant synthetic peptides. However, DC from either early or late stages of HIV-1 infection could not overcome the defect in anti-HIV-1 CTLm response in advanced infection.
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948
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Wang L, Jacques SL, Zheng L. CONV--convolution for responses to a finite diameter photon beam incident on multi-layered tissues. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 1997; 54:141-50. [PMID: 9421660 DOI: 10.1016/s0169-2607(97)00021-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A convolution program (CONV) solving responses to a collimated finite diameter photon beam perpendicularly incident on a multi-layered tissue has been coded in ANSI Standard C, hence, the program can be executed on various computers. The program, employing an extended trapezoidal rule for integration, convolves the responses to an infinitely narrow photon beam computed by a companion program (MCML). Dynamic data allocation is used for CONV as well as MCML, therefore, the number of tissue layers and grid elements of the grid system can be varied at run time. The potential error due to not scoring the first photon-tissue interactions separately is illustrated. The program, including the source code, has been in the public domain since 1992 and can be downloaded from the web site at http:(/)/biomed.tamu.edu/-lw.
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Abstract
Phacoemulsification of the lens in eyes with zonular loss risks dislocation of the lens into the vitreous cavity. We describe the use of iris hooks after capsulorhexis to support the lens during surgery. With iris hooks, the lens can be stabilized, helping prevent additional loss of zonules and permitting retention of the capsule to support an intraocular lens.
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950
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Hornung F, Zheng L, Lenardo MJ. Maintenance of clonotype specificity in CD95/Apo-1/Fas-mediated apoptosis of mature T lymphocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1997; 159:3816-22. [PMID: 9378969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ag-induced mature T cell apoptosis is the result of death-inducing cytokines, including the ligand for CD95 (Apo-1/Fas). This raises the possibility that expression of this death molecule could affect bystander T cells that were not directly antigenically stimulated but that express the CD95 receptor. We show here that bystander T cells, even if they express the CD95 receptor, are not killed when exposed to T cells undergoing Ag-induced apoptosis. Rather, cell death is restricted to T cells that bear the receptor clonotype that is specifically engaged by TCR ligands. At least one mechanism of clonotype restriction is a significant enhancement of CD95-induced apoptosis by TCR ligation. Our results demonstrate that, in addition to the well-known ability of TCR to stimulate apoptosis by inducing CD95 ligand expression, TCR signals at the time of CD95 engagement can effectively increase apoptosis. Therefore, we put forward the hypothesis that strict clonotype specificity is preserved when death cytokines such as CD95 ligand induce autoregulatory mature T cell apoptosis, at least in part through a sensitization signal provided by the TCR stimulation.
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