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Lees RM, Xu LH. On the Assignment of Optically Pumped Far-Infrared Laser Emission from CH(3)OH. JOURNAL OF MOLECULAR SPECTROSCOPY 1999; 196:220-234. [PMID: 10409452 DOI: 10.1006/jmsp.1999.7876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Progress in the analysis of the infrared spectrum of CH(3)OH in the 930-1450 cm(-1) region has led to assignments, confirmations, or new insights for a number of far-infrared laser (FIRL) transition systems optically pumped by CO(2) lasers. Many of the systems involve FIRL transitions among the CO-stretching, CH(3)-rocking, OH-bending, and CH(3)-deformation vibrational modes, giving useful information on the torsion-rotation structure of the methanol vibrational energy manifold. Some anomalies and mysteries concerning the identity of the lasing levels have been resolved, but several new ones have arisen. Altogether, 45 CH(3)OH IR-pump/FIR-laser systems are examined in light of the new spectroscopic information; about half of the system assignments are new and half have been previously reported in the literature and are here confirmed, extended, or revised. Copyright 1999 Academic Press.
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He XH, Shaw PC, Xu LH, Tam SC. Site-directed polyethylene glycol modification of trichosanthin: effects on its biological activities, pharmacokinetics, and antigenicity. Life Sci 1999; 64:1163-75. [PMID: 10210259 DOI: 10.1016/s0024-3205(99)00048-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Trichosanthin (TCS), a type I ribosome-inactivating protein (RIP), was modified with polyethylene glycol (PEG) in order to reduce its antigenicity and prolong its half-life. Computer modeling identified three potential antigenic sites namely Q219, K173 and S7. By site-directed mutagenesis, these sites were changed into cysteine through which PEG can be covalently attached. The resulting TCS had a PEG coupled directly above one of its potential antigenic determinants, hence masking the antigenic region and prevent binding of antibodies specific to this site. In general, mutation did not bring about significant changes in ribosome-inactivating activity, cytotoxicity, and abortifacient activity of TCS. However, the in vitro activities of PEG modified (PEGylated) TCS muteins were 3-20 folds lower and the in vivo activity 50% less than that of nTCS. Pharmacokinetics study indicated that all three PEGylated TCS muteins showed 6-fold increase in mean residence time as compared to unmodified muteins. The binding affinity of an IgE monoclonal antibody (TE1) to TCS was greatly reduced after PEG modification (PEGylation) at position Q219, suggesting that TE1 recognized an epitope very near to residue Q219. PEGylated TCS muteins induced similar IgG response but 4-16 fold lower IgE response in mice compared with nTCS.
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Xu LH, Jin X, Mao PH, Lu ZF, Cui XL, Jiang CL. Three new species of the genus Actinobispora of the family Pseudonocardiaceae, Actinobispora alaniniphila sp. nov., Actinobispora aurantiaca sp. nov. and Actinobispora xinjiangensis sp. nov. INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY 1999; 49 Pt 2:881-6. [PMID: 10319514 DOI: 10.1099/00207713-49-2-881] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The genus Actinobispora Jiang et al. is characterized by the formation of longitudinally paired spores on both the vegetative and the aerial mycelium, absence of mycolic acid, cell wall chemotype IV (containing meso-diaminopimelic acid as the diamino acid, galactose and arabinose), PVI and MK-9(H2). Comparative studies of morphology, chemical classification and phylogenetic analysis based on the 16S rRNA sequences among the four type strains of the genus Actinobispora and type strains of related genera were carried out. The results indicated that the genus Actinobispora is different from these other genera and should be placed in the family Pseudonocardiaceae Embley et al. 1988 with the genera Amycolatopsis, Pseudonocardia, Saccharomonospora, Saccharopolyspora and Actinopolyspora. On the bases of these results, three new species under the names of Actinobispora alaniniphila sp. nov., Actinobispora aurantiaca sp. nov. and Actinobispora xinjiangensis sp. nov. are proposed; the type strains are CCTCC AA97001T, CCTCC AA97002T and CCTCC AA97020T.
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Ahrendt SA, Chow JT, Xu LH, Yang SC, Eisenberger CF, Esteller M, Herman JG, Wu L, Decker PA, Jen J, Sidransky D. Molecular detection of tumor cells in bronchoalveolar lavage fluid from patients with early stage lung cancer. J Natl Cancer Inst 1999; 91:332-9. [PMID: 10050866 DOI: 10.1093/jnci/91.4.332] [Citation(s) in RCA: 247] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Conventional cytologic analysis of sputum is an insensitive test for the diagnosis of non-small-cell lung cancer (NSCLC). We have recently demonstrated that polymerase chain reaction (PCR)-based molecular methods are more sensitive than cytologic analysis in diagnosing bladder cancer. In this study, we examined whether molecular assays could identify cancer cells in bronchoalveolar lavage (BAL) fluid. METHODS Tumor-specific oncogene mutations, CpG-island methylation status, and microsatellite alterations in the DNA of cells in BAL fluid from 50 consecutive patients with resectable (stages I through IIIa) NSCLC were assessed by use of four PCR-based techniques. RESULTS Of 50 tumors, 28 contained a p53 mutation, and the identical mutation was detected with a plaque hybridization assay in the BAL fluid of 39% (11 of 28) of the corresponding patients. Eight of 19 adenocarcinomas contained a K-ras mutation, and the identical mutation was detected with a mutation ligation assay in the BAL fluid of 50% (four of eight) of the corresponding patients. The p16 gene was methylated in 19 of 50 tumors, and methylated p16 alleles were detected in the BAL fluid of 63% (12 of 19) of the corresponding patients. Microsatellite instability in at least one marker was detected with a panel of 15 markers frequently altered in NSCLC in 23 of 50 tumors; the identical alteration was detected in the BAL fluid of 14% (three of 22) of the corresponding patients. When all four techniques were used, mutations or microsatellite instability was detected in the paired BAL fluid of 23 (53%) of the 43 patients with tumors carrying a genetic alteration. CONCLUSION Although still limited by sensitivity, molecular diagnostic strategies can detect the presence of neoplastic cells in the proximal airway of patients with surgically resectable NSCLC.
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Xu LH, Yang X, Craven RJ, Cance WG. The COOH-terminal domain of the focal adhesion kinase induces loss of adhesion and cell death in human tumor cells. CELL GROWTH & DIFFERENTIATION : THE MOLECULAR BIOLOGY JOURNAL OF THE AMERICAN ASSOCIATION FOR CANCER RESEARCH 1998; 9:999-1005. [PMID: 9869300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Focal adhesion kinase (FAK) is a tyrosine kinase that is linked to signaling pathways between cells and their extracellular matrix. An alternate transcript of the COOH-terminal region of the FAK gene, called FAK-related nonkinase, has been shown to act as an inhibitor of FAK in chicken embryo fibroblasts. We have designed an analogous segment of human FAK, FAK COOH-terminal domain (FAK-CD), and transfected this construct into human tumor cells. Expression of FAK-CD inhibited cell growth in BT474 human breast cancer cells and C8161 human melanoma cells. To characterize the nature of growth inhibition, we developed an inducible system of FAK-CD expression and demonstrated that the induced FAK-CD protein localized to focal adhesions, causing cellular rounding, an irreversible loss of adhesion, and subsequent cell death. In addition, expression of FAK-CD reduced tyrosine phosphorylation of FAK, suggesting that FAK-CD may be a potent inhibitor of FAK in human tumor cells.
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Stone SC, Philips LA, Fraser GT, Lovas FJ, Xu LH, Sharpe SW. High-Resolution Microwave and Infrared Molecular-Beam Studies of the Conformers of 1,1,2,2-Tetrafluoroethane. JOURNAL OF MOLECULAR SPECTROSCOPY 1998; 192:75-85. [PMID: 9770390 DOI: 10.1006/jmsp.1998.7664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
High-resolution microwave and infrared molecular-beam spectra have been measured for 1,1,2,2-tetrafluoroethane (HFC134). For the higher energy, polar, C2 symmetry, gauche conformer, microwave spectra have been recorded for the normal and mono-13C isotopomers and analyzed to determine a C-C bond length of 1.512(4) Å, in good agreement with a recent ab initio value (MP2/6-31G**) of 1.515 Å [S. Papasavva, K. H. Illinger, and J. E. Kenny, J. Phys. Chem. 100, 10100-10110 (1996)]. A tunable microwave-sideband CO2 laser and electric-resonance optothermal spectrometer have been used to measure the infrared spectrum of the nu6, C-C stretch of the gauche conformer near 906 cm-1. Microwave-infrared double resonance and precise ground state combination differences provided by the microwave measurements guide the assignment of the spectrum. The observation of a c-type spectrum definitively establishes that the upper state vibration is of A symmetry in the C2 point group. The spectrum is fit to a Watson asymmetric-top Hamiltonian to a standard deviation of 0.24 MHz. A weak perturbation shifts the line positions for transitions near J = Kc = 20 by as much as 12 MHz. The identity of the perturber is unknown. Pulsed slit-jet diode-laser spectra have been recorded for the nu16 vibration of the anti conformer near 1127 cm-1. An a- and c-type hybrid band is observed, consistent with a Bu symmetry mode. Previous low-resolution studies have attributed the 1127-cm-1 mode to either a Bu or an Au symmetry vibration. A total of 522 nonblended transitions were assigned and fit to determine ground and excited state constants. The ground state constants of A = 5134.952(65) MHz, B = 3148.277(27) MHz, and C = 2067.106(43) MHz are the first experimental determinations of the rotational constants for this conformer. Here, type A standard uncertainties are given in the parentheses. Copyright 1998 Academic Press.
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Xu LH, Tiang YQ, Zhang YF, Zhao LX, Jiang CL. Streptomyces thermogriseus, a new species of the genus Streptomyces from soil, lake and hot-spring. INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY 1998; 48 Pt 4:1089-93. [PMID: 9828410 DOI: 10.1099/00207713-48-4-1089] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Many thermophilic actinomycetes were isolated from samples collected from a hot-spring, lake and soil in Yunnan, China. Chemical and molecular classification of four selected strains of thermophilic Streptomyces with an upper limited growth temperature of 65-68 degrees C and autolytic characteristics was carried out. A new species, Streptomyces thermogriseus sp. nov. is described. The type strain is Y-14046T (= CCTCC AA97014T).
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Jin X, Xu LH, Mao PH, Hseu TH, Jiang CL. Description of Saccharomonospora xinjiangensis sp. nov. based on chemical and molecular classification. INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY 1998; 48 Pt 4:1095-9. [PMID: 9828411 DOI: 10.1099/00207713-48-4-1095] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Comparative studies of morphology, physiology, biochemistry and chemical composition of cells, and phylogenetic analysis based on 16S rRNA gene sequences were carried out with strains XJ-54T and XJ-58 of the genus Saccharomonospora and type strains of related genera. The results indicated that the two strains are different from known members of the genus Saccharomonospora. A new species with the name Saccharomonospora xinjiangensis sp. nov. is proposed. The new species is characterized by the presence of longitudinal pairs of spores on both the aerial and the vegetative hyphae and contains phosphatidyl ethanolamine, phosphatidyl choline and unknown glucosamine-containing phospholipids, and the major menaquinones MK-9(H2), MK-9(H4) and MK-7(H4).
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Vasconcellos ECC, Zerbetto SC, Zink LR, Evenson KM, Lees RM, Xu LH. C-13 Methanol Far-Infrared Laser: Newly Discovered Lines, Predictions, and Assignments. JOURNAL OF MOLECULAR SPECTROSCOPY 1998; 188:102-105. [PMID: 9480807 DOI: 10.1006/jmsp.1997.7496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report 25 new laser lines from 13CH3OH methanol when pumped by a cw CO2 laser. The majority of the lines are pumped by the 10R (regular) and 10SR (sequence) bands of the CO2 laser. Two are pumped by the 9HP(20) hot-band CO2 line. We measured 22 laser frequencies in this molecule, 19 from new lines and three from previously reported lines. We also remeasured and corrected the frequency of the 9P(44) pumped line as 3 378 404.87 MHz (88.738 μm). We assigned two lines-10SR(17), 77.5758 cm-1 and 10R(50), 119.3020 cm-1-and predicted other potential far-infrared laser lines with these two pumps. Copyright 1998 Academic Press.
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Walsh MS, Xu LH, Lees RM. Global Fit of Torsion-Rotation Transitions in the Ground and First Excited Torsional States of CD3OH Methanol. JOURNAL OF MOLECULAR SPECTROSCOPY 1998; 188:85-93. [PMID: 9480805 DOI: 10.1006/jmsp.1997.7503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A global analysis of reported microwave (MW) millimeter wave (MMW), and Fourier-transform far-infrared (FTFIR) spectra of the CD3OH isotopic species of methanol has been carried out for the first two torsional states (nut = 0 below the barrier and nut = 1 straddling the barrier) of the ground vibrational state. The CD3OH data set contains 472 MW and MMW lines and 5320 FTFIR lines, representing the most recent available information in the quantum number ranges J </= 20 and K </= 15. The transitions have been successfully fitted to within the assigned measurement uncertainties of ±100 kHz for most of the MW and MMW lines and ±6 MHz for the FIR lines with the use of a program (I. Kleiner and M. Godefroid, private communication) based on the formalism of Herbst et al. (J. Mol. Spectrosc. 108, 42-57, 1984). A convergent global fit was achieved using 54 adjustable parameters to reach an overall weighted standard deviation of 0.966. The new parameters for CD3OH are compared with previous global fitting results for the 12CH3OH and 13CH3OH isotopomers. Copyright 1998 Academic Press.
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Predoi-Cross A, Xu LH, Walsh MS, Lees RM, Winnewisser M, Lichau H. New Measurements and Assignments in the Millimeter-Wave Spectrum of CD3OH. JOURNAL OF MOLECULAR SPECTROSCOPY 1998; 188:94-101. [PMID: 9480806 DOI: 10.1006/jmsp.1997.7504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The ground state rotational spectrum of CD3OH has been revisited in the millimeter-wave range. A total of 216 transition frequencies have been measured and assigned in the 117-179 GHz spectral range, including about 40 transitions previously reported. The spectrum was recorded at the Justus-Liebig University in Giessen, Germany using a frequency modulated millimeter-wave spectrometer. The assignments for the CD3OH transitions were predicted based on energy levels calculated using preliminary results of the global fit of microwave, millimeter-wave, and far-infrared data of Walsh et al. (Paper FC04 presented at the 52nd International Symposium of Molecular Spectroscopy, Columbus, OH, 1997). The new measurements have substantially enlarged the accurate millimeter-wave component of the data set available for the global fit and have allowed Walsh et al. to obtain significant improvement in the CD3OH molecular parameters (J. Mol. Spectrosc. 188, 85-93, 1998). The low residuals between observed and calculated frequencies highlight the quality of the global fit results. Copyright 1998 Academic Press.
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Lu YJ, Guo SP, Tong T, Xu LH, Dong XY, Hana NJ, Cheng SJ. Establishment and characterization of a SV40T-transformed human bronchial epithelial cell line. Lung Cancer 1998; 19:15-24. [PMID: 9493136 DOI: 10.1016/s0169-5002(97)00073-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The majority of human lung cancers originate from the carcinogenesis of bronchial epithelial cells. To study the malignant progression of human bronchial epithelial cells, we established a SV40T-transformed human bronchial epithelial cell line, and observed some biological and genetic changes of the cell line at different passages. In a 2-year culture, this cell line was approaching malignancy without obvious senescence. Cells in a later passage proliferated faster and required less growth factors than those of an early passage. After continued passaging, these cells were resistant to the terminal squamous differentiation effects of serum, and many of the cells grew anchorage independently. However, no tumor formed after cells were injected into nude mice. Some genetic alterations were found accompanying those morphological changes, such as 3p- and activation of c-myc, c-erbB-2 and bcl2, suggesting that those genetic alterations may contribute to the carcinogenesis of human bronchial epithelial cells at an early stage. This cell line should be particularly useful for studying the progression of human lung cancers.
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Xiao YD, Xu LH, Jing DM. [Study on phlebitis caused by intravenous drips]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1997; 32:717-8. [PMID: 10455606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Xu LH, Wang X, Cronin TJ, Perry DS, Fraser GT, Pine AS. Sub-Doppler Infrared Spectra and Torsion-Rotation Energy Manifold of Methanol in the CH-Stretch Fundamental Region. JOURNAL OF MOLECULAR SPECTROSCOPY 1997; 185:158-172. [PMID: 9344807 DOI: 10.1006/jmsp.1997.7367] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The infrared spectrum of jet-cooled methanol in the CH-stretch fundamental region has been investigated by two sub-Doppler laser techniques: optothermally detected molecular-beam electric resonance and direct-absorption slit-jet spectroscopy. With the aid of microwave-infrared double resonance and ground state combination differences, 27 subbands in the frequency range 2967 to 3027 cm-1 have been assigned to the nu2 fundamental. Perturbation systems in the K' = 0 E, -1 E, and -2 E symmetry subbands have been analyzed to yield matrix elements of 0.013, 0.041, and 0.75 cm-1, respectively. The A-E torsional tunneling splitting for J = 0 of the nu2 vibration of -3.26 cm-1 is of opposite sign and a factor of three smaller in magnitude than the ground state value of +9.12 cm-1. Copyright 1997 Academic Press. Copyright 1997Academic Press
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Wei G, Xu LH. [Psychosomatic nursing care of the patient with continent urinary diversion]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1996; 31:580-2. [PMID: 9295531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Lu YJ, Dong XY, Guo SP, Zhang RG, Ke Y, Zhang LZ, Xu LH, Cheng SJ. 2q-, a non-random chromosomal abnormality in human non-small-cell lung cancer. Carcinogenesis 1996; 17:1589-93. [PMID: 8761414 DOI: 10.1093/carcin/17.8.1589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Many cytogenetic studies have been carried out on human lung cancer. However the chromosomal alterations in human lung cancers are often complex, making it difficult to identify some abnormal chromosomes by routine cytogenetic studies. Using FISH (fluorescence in situ hybridization), we studied the alterations of chromosome 2, 3, and 17 in four human bronchial epithelial cell lines, two human non-small-cell lung cancer (NSCLC) cell lines, and 12 primary NSCLC specimens. 2q- was found in three out of four human bronchial epithelial cell lines, two NSCLC cell lines, and three out of seven primary NSCLC specimens tested. 3p- was noted in five cases of twelve primary NSCLC patients examined. 3p- was the first cytogenetic discovery and the most prominent abnormality in lung cancer. 2q- has rarely been reported in human lung cancer but loss of heterozygosity by RFLP analysis for 2q had been reported in human NSCLC. Our results indicate that 2q- was also a non-random chromosomal abnormality in the early stage of the development of human NSCLC. There would be one or more putative tumor suppressor gene(s) on the long arm of chromosome 2. Loss of the gene(s) presumably contributes to the carcinogenesis of human non-small-cell lung cancer.
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Xu LH, Owens LV, Sturge GC, Yang X, Liu ET, Craven RJ, Cance WG. Attenuation of the expression of the focal adhesion kinase induces apoptosis in tumor cells. CELL GROWTH & DIFFERENTIATION : THE MOLECULAR BIOLOGY JOURNAL OF THE AMERICAN ASSOCIATION FOR CANCER RESEARCH 1996; 7:413-8. [PMID: 9052982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase implicated in integrin-mediated signal transduction pathways, oncogenic transformation by v-src, and the invasion of human tumors. The overexpression of p125FAK in a variety of human tumors and tumor cell lines in comparison to their nontransformed counterparts suggested that attenuation of p125FAK expression might have an effect on tumor cell proliferation. In this study, we have treated tumor cell lines that expressed high levels of p125FAK with different antisense oligonucleotides to FAK, and have specifically attenuated p125FAK expression. The cells treated with antisense oligonucleotides not only lost their attachment, but also underwent apoptosis. Extensive control oligonucleotide experiments suggested that this attenuation was highly FAK specific. Furthermore, normal human fibroblasts, which did not express high levels of p125FAK, did not lose their attachment or become apoptotic with FAK antisense treatment. These results suggested that FAK is involved in adhesion-mediated growth in tumor cells and that FAK may be a rational gene-directed target for disrupting tumor cell growth.
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Rinehart CA, Xu LH, Van Le L, Kaufman DG. Diethylstilbestrol-induced immortalization of human endometrial cells: alterations in p53 and estrogen receptor. Mol Carcinog 1996; 15:115-23. [PMID: 8599578 DOI: 10.1002/(sici)1098-2744(199602)15:2<115::aid-mc4>3.0.co;2-i] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Carcinogenesis is a process requiring multiple steps. Immortalization is one step in this process and may be rate limiting. To further our understanding of estrogen-induced carcinogenesis, we evaluated diethylstilbestrol (DES)-induced immortalization of human endometrial stromal cells. This was achieved by assessing at the restrictive temperature the colony-forming efficiency of cells that were conditionally immortalized with a temperature-sensitive simian virus 40 large T antigen. Treatment with DES for 1 wk did not increase the immortalization frequency; however, cultures that were treated for 20 wk had a twofold increase in immortalization frequency, and continued treatment for a total of 44 wk produced a threefold increase in immortalization frequency that was dose dependent. DES-treated restrictive temperature variants (RTVs) but not spontaneous RTVs lost the temperature-sensitive phenotype. DES-RTVs also had a shorter doubling time than spontaneous RTVs did. p53 expression was increased in DES-RTVs, and its localization within the cell was altered. Conversely, expression of the estrogen receptor was decreased in DES-immortalized cells. These changes in gene expression often occur in estrogen-related malignancies, and our results are consistent with a causal role for estrogens in these p53 and the estrogen receptor alterations. Immortalization of human cells may be analogous to initiation of rodent cells, and our results suggest that estrogen-induced alterations in p53 or other genes that regulate life span could contribute to estrogen-induced initiation.
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Stern RM, Hu S, Uijtdehaage SH, Muth ER, Xu LH, Koch KL. Asian hypersusceptibility to motion sickness. Hum Hered 1996; 46:7-14. [PMID: 8825456 DOI: 10.1159/000154318] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A rotating optokinetic drum was used in three laboratory studies to test the hypothesis that Asian subjects are hypersusceptible to motion sickness. The results of the first study showed that Chinese women compared to European-American and African-American women experienced significantly more severe symptoms of motion sickness and greater disturbance of normal gastric myoelectric activity. A second study yielded similar results using American-born children of Asian parents. The results of a third study using Chinese men and women were similar and showed a significant increase in vasopressin during rotation. Possible genetic mechanisms that may account for these results are discussed.
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Xu LH, Rinehart CA, Kaufman DG. Estrogen-induced anchorage-independence in human endometrial stromal cells. Int J Cancer 1995; 62:772-6. [PMID: 7558429 DOI: 10.1002/ijc.2910620621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Estrogens are important etiologic agents for most gynecologic malignancies, and chronic exposure to estrogen that is unopposed by progestins conveys the greatest risk. Treatments with estrogen facilitate the process of malignant transformation in rodents, but relatively few studies of estrogen-induced carcinogenesis have been performed using human cells. Most malignancies in estrogen-responsive tissues arise from epithelial cells, but an increasing body of evidence emphasizes the role of stromal cells as mediators of the effects of estrogens on epithelial cells. Our studies were designed to assess estrogens as carcinogens for human endometrial stromal cells and to provide a basis for studies of the role of stroma in estrogen-induced carcinogenesis in humans. Acute treatments with the estrogens diethylstilbestrol (DES), 17 beta-estradiol (E2) and beta-dienestrol enhance anchorage-independent proliferation (AIP) of SV40-immortalized human endometrial stromal cells in the rank order of DES > E2 > beta-dienestrol. The anti-estrogenic compound tamoxifen inhibits DES-induced AIP. The magnitude of DES-induced AIP increases with prolonged duration of treatment. After 11 months of chronic treatment with 0.1 nM DES, AIP was 20-fold higher than in vehicle-treated control cultures. Expression of the estrogen receptor was altered by treatments with DES in parallel with increased capacity for AIP. These conditionally immortal human endometrial stromal cells appear to be a good model for estrogen-induced transformation of human cells.
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Craven RJ, Xu LH, Weiner TM, Fridell YW, Dent GA, Srivastava S, Varnum B, Liu ET, Cance WG. Receptor tyrosine kinases expressed in metastatic colon cancer. Int J Cancer 1995; 60:791-7. [PMID: 7896447 DOI: 10.1002/ijc.2910600611] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Using a PCR-based cloning technique, we have isolated a series of DNA fragments coding for tyrosine kinases that are expressed in a metastatic human colon tumor, and have subsequently analyzed their expression pattern at the protein level in human tumors. We identified both the alpha and the beta forms of the platelet-derived growth factor receptor (PDGFR), axl and 8 other genes, including 3 cytoplasmic tyrosine kinases. To study their expression in human colon cancer, we performed Western blots of matched sets of normal tissues and of carcinomas from the same patient. These revealed that the alpha-PDGFR migrates predominantly as a 200-kDa band in 8/8 normal tissues, and as a 170-kDa band in 17/17 malignant tissues, as well as in colonic polyps, suggesting that expression of an isoform of this receptor may be a marker for the progression of colon cancer. Additional studies showed that the Axl receptor tyrosine kinase was expressed at 10-fold higher levels in a peritoneal metastatic nodule than in other normal and malignant tissues. Immunohistochemistry revealed Axl over-expression specifically in the malignant cells of the tumor. This indicates that over-expression and possibly a differential processing event of tyrosine kinase receptors may be involved in colon cancer, and that they are potential markers for the progression of this disease.
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Xu LH, Zhou SJ, Lian WN, Mao MZ, Yu YF. Electron microscopic observations of tegumental damage in adult Schistosoma japonicum after in vivo treatment with levo-praziquantel. Chin Med J (Engl) 1994; 107:771-4. [PMID: 7835105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The in vivo effects of a single dose of levo-praziquantel, 75 mg/kg in PEG 400, on the tegumental surface of adult S. japonicum were compared with the effects of a single dose (150 mg/kg) of the mixed isomer preparation, using scanning and transmission electron microscope. Worms were recovered from mice at 10 min, 30 min, 1 hr, 4 hr, 12 hr, 24 hr and 48 hr after treatment. After 10 min exposure to either compound, the tegumental folds and sensory organelles were swollen and the tegument vacuolated. After 12-24 hr, the surface was eroded and exfoliated with exposure of intrategumental and/or subtegumental tissues and attachment of leukocytes to the denuded areas. Vehicle controls were normal throughout the time period examined. These studies demonstrate that the levo isomer of praziquantel causes acute structural damage to the tegument similar to that seen with the mixed isomer preparation.
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Xu LH, Koch KL, Summy-Long J, Stern RM, Seaton JF, Harrison TS, Demers LM, Bingaman S. Hypothalamic and gastric myoelectrical responses during vection-induced nausea in healthy Chinese subjects. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 265:E578-84. [PMID: 8238333 DOI: 10.1152/ajpendo.1993.265.4.e578] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The physiology of nausea, a uniquely human symptom, is poorly understood. The purpose of this study was to measure the temporal sequences of neurohormonal responses and gastric myoelectrical activity in healthy subjects during the rotation of an optokinetic drum that produced nausea and other symptoms of motion sickness. Plasma catecholamines, vasopressin, and cortisol were measured at baseline, during minutes 1-5, 6-10, and 11-15 of drum rotation, and after rotation stopped. Electrogastrograms were recorded throughout the study. Twelve subjects (80%) developed nausea and 4-9 cycles/min of gastric tachyarrhythmias; three subjects had no nausea and no gastric dysrhythmias. Tachyarrhythmias began 3.4 +/- 0.8 min after the onset of drum rotation, and nausea was reported, on average, 3 min later. During minutes 6-10 of drum rotation, vasopressin levels significantly increased in the subjects with nausea compared with subjects without nausea (P < 0.04). In the subjects with nausea, epinephrine and vasopressin increased significantly (P < 0.05) compared with baseline during minutes 6-10 and 11-15 of drum rotation. As nausea resolved during recovery, vasopressin decreased by 74%, whereas epinephrine increased 13%. We conclude that 1) in nauseated subjects, endogenous vasopressinergic and sympathetic circuits are activated before hypothalamic-pituitary-adrenal pathways, 2) plasma vasopressin levels correlate most closely with the temporal onset and resolution of nausea, and 3) peripheral gastric dysrhythmias may have a role in activating central vasopressinergic neurons.
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Xu LH. [Production of monoclonal antibody that recognize the common antigen of black-pigmented bacteroides and application in pulp and periapical diseases]. ZHONGHUA KOU QIANG YI XUE ZA ZHI = ZHONGHUA KOUQIANG YIXUE ZAZHI = CHINESE JOURNAL OF STOMATOLOGY 1993; 28:90-2. [PMID: 7900976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Wu HF, Xu LH, Jenzano JW, Rinehart CA, Kaufman DG, Lundblad RL. Expression of tissue kallikrein in normal and SV40-transfected human endometrial stromal cells. Pathobiology 1993; 61:123-7. [PMID: 8216833 DOI: 10.1159/000163780] [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: 01/29/2023] Open
Abstract
The polymerase chain reaction with specific tissue kallikrein primers was utilized to demonstrate the presence of tissue kallikrein mRNA in human endometrial stromal cells. Enzymatic analysis measured with a specific tripeptide nitroanilide substrate demonstrated the presence of tissue kallikrein in the conditioned medium obtained from both normal stromal cells and stromal cells transfected with an origin-defective temperature-sensitive SV40 large T antigen. The transfected stromal cell supernatant exhibited approximately twice as much tissue kallikrein activity as normal stromal cells at 60-100% of cell confluence. The release of tissue kallikrein from transfected stromal cells was confirmed by Western blot analysis and [35S]-methionine incorporation into a 35-kD protein which retains tissue kallikrein activity. These results demonstrate for the first time the expression and secretion of tissue kallikrein in human endometrial stromal cells and provide evidence of possible involvement of tissue kallikrein in cell transformation.
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