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Cui L, Quan R, Xiao W. Sleeping sites of black‐and‐white snub‐nosed monkeys (
Rhinopithecus bieti
) at Baima Snow Mountain, China. J Zool (1987) 2006. [DOI: 10.1111/j.1469-7998.2006.00137.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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152
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Wang XW, Li J, Guo T, Zhen B, Kong Q, Yi B, Li Z, Song N, Jin M, Xiao W, Zhu X, Gu C, Yin J, Wei W, Yao W, Liu C, Li J, Ou G, Wang M, Fang T, Wang G, Qiu Y, Wu H, Chao F, Li J. Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2005; 52:213-221. [PMID: 16312970 DOI: 10.2166/wst.2005.0266] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.
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Barbier AJ, Berridge C, Dugovic C, Laposky AD, Wilson SJ, Boggs J, Aluisio L, Lord B, Mazur C, Pudiak CM, Langlois X, Xiao W, Apodaca R, Carruthers NI, Lovenberg TW. Acute wake-promoting actions of JNJ-5207852, a novel, diamine-based H3 antagonist. Br J Pharmacol 2004; 143:649-61. [PMID: 15466448 PMCID: PMC1575430 DOI: 10.1038/sj.bjp.0705964] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 07/13/2004] [Accepted: 07/21/2004] [Indexed: 11/08/2022] Open
Abstract
1 1-[4-(3-piperidin-1-yl-propoxy)-benzyl]-piperidine (JNJ-5207852) is a novel, non-imidazole histamine H3 receptor antagonist, with high affinity at the rat (pKi=8.9) and human (pKi=9.24) H3 receptor. JNJ-5207852 is selective for the H3 receptor, with negligible binding to other receptors, transporters and ion channels at 1 microm. 2 JNJ-5207852 readily penetrates the brain tissue after subcutaneous (s.c.) administration, as determined by ex vivo autoradiography (ED50 of 0.13 mg kg(-1) in mice). In vitro autoradiography with 3H-JNJ-5207852 in mouse brain slices shows a binding pattern identical to that of 3H-R-alpha-methylhistamine, with high specific binding in the cortex, striatum and hypothalamus. No specific binding of 3H-JNJ-5207852 was observed in brains of H3 receptor knockout mice. 3 In mice and rats, JNJ-5207852 (1-10 mg kg(-1) s.c.) increases time spent awake and decreases REM sleep and slow-wave sleep, but fails to have an effect on wakefulness or sleep in H3 receptor knockout mice. No rebound hypersomnolence, as measured by slow-wave delta power, is observed. The wake-promoting effects of this H3 receptor antagonist are not associated with hypermotility. 4 A 4-week daily treatment of mice with JNJ-5207852 (10 mg kg(-1) i.p.) did not lead to a change in body weight, possibly due to the compound being a neutral antagonist at the H3 receptor. 5 JNJ-5207852 is extensively absorbed after oral administration and reaches high brain levels. 6 The data indicate that JNJ-5207852 is a novel, potent and selective H3 antagonist with good in vitro and in vivo efficacy, and confirm the wake-promoting effects of H3 receptor antagonists.
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154
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Xiao W, Zhou J, Prineas J. Storage of ultrashort optical pulses in a resonantly absorbing Bragg reflector. OPTICS EXPRESS 2003; 11:3277-3283. [PMID: 19471455 DOI: 10.1364/oe.11.003277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A practical method of slowing and stopping an incident ultrashort light pulse with a resonantly absorbing Bragg reflector is demonstrated numerically. It is shown that an incident laser pulse with suitable pulse area evolves from a given pulse waveform into a stable, spatially-localized oscillating or standing gap soliton. We show that multiple gap solitons can be simultaneously spatially localized, resulting in efficient optical energy conversion and storage in the resonantly absorbing Bragg structure as atomically coherent states.
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155
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Gao G, Zhou X, Alvira MR, Tran P, Marsh J, Lynd K, Xiao W, Wilson JM. High throughput creation of recombinant adenovirus vectors by direct cloning, green-white selection and I-Sce I-mediated rescue of circular adenovirus plasmids in 293 cells. Gene Ther 2003; 10:1926-30. [PMID: 14502222 DOI: 10.1038/sj.gt.3302088] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Ability of replication-defective adenovirus vectors to achieve efficient gene transfer in most of the mammalian cell types makes them useful vehicles for many gene transfer applications, including their use in assessing gene function. High throughput creation of recombinant adenovirus becomes a critical path to the expanding utility of adenovirus vector technology. Here, we report a process in which recombinant adenovirus vectors are isolated as single molecular clones through a convenient direct cloning and green-white selection procedure, and directly transfected into 293 cells where virus is rescued through an enzymatic reaction mediated by an intron-encoding rare endonuclease I-Sce I. This process of enzymatic rescue of circular molecular clones was at least 10-fold more efficient than that using linearized clones for transfection. This method will facilitate a high throughput creation of vectors as required for screening gene function.
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156
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Feezor RJ, Baker HV, Mindrinos M, Tannahill CL, Brownstein B, Fay A, MacMillan S, Laramie J, Hayden D, Schoenfeld D, Xiao W, Moldawer LL, Cobb JP, Davis R, Tompkins R. RNA ISOLATION METHODS AFFECT THE MEASURE-MENT OF HUMAN LEUKOCYTE GENE EXPRESSION RESULTING FROM SEB STIMULATION. Shock 2003. [DOI: 10.1097/00024382-200306001-00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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157
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Sarkar R, Xiao W, Kazazian HH. A single adeno-associated virus (AAV)-murine factor VIII vector partially corrects the hemophilia A phenotype. J Thromb Haemost 2003; 1:220-6. [PMID: 12871492 DOI: 10.1046/j.1538-7836.2003.00096.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A major obstacle for delivery of factor (F)VIII using adeno-associated virus (AAV) vectors is the large size of FVIII cDNA, which is well above the 5 kb packaging limit for AAV. Here we construct a < 5 kb FVIII-AAV vector using murine FVIII cDNA and a strong liver-specific albumin promoter. We assessed the efficacy of this vector using three different routes of administration, intraportal, intrasplenic and tail vein injection, in FVIII knockout (FVIII KO) mice. The peak level of FVIII observed was about 8% of normal mouse FVIII activity. Even at 9 months, post vector injection, 14 of 19 mice receiving FVIII-AAV demonstrated phenotypic correction and roughly 2% FVIII activity. The transgene copy number ranged from 0.001 to 0.1 copies per cell, depending upon the somatic tissue. The potential for germline transmission of AAV was assayed in 34 pups obtained from five pairs of treated, phenotypically corrected adult hemophilic mice. Although the parents harbored the transgene in liver, spleen, and gonads, none of the 34 offspring was positive for the transgene, suggesting that the risk of inadvertent germline transmission is low.
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158
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Liu YL, Wagner K, Robinson N, Sabatino D, Margaritis P, Xiao W, Herzog RW. Optimized production of high-titer recombinant adeno-associated virus in roller bottles. Biotechniques 2003; 34:184-9. [PMID: 12545558 DOI: 10.2144/03341dd07] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Adeno-associated viral (AAV) vectors are used for in vivo gene transfer in a number of preclinical models of genetic diseases (including large-animal models) and are currently being tested in clinical trials for treatment of hemophilia B and cystic fibrosis. Protocols for production of AAV vectors in a helper virus-free system are available and are based on transient transfection of HEK-293 cells with multiple plasmids. Scale-up of vector production has been labor intensive and inefficient because of a lack of larger culture vessels suitable for growth of adherent cells, large-scale transfection, and vector production. Here we report efficient production of AAV vector in roller bottles, which represents a 10-fold scale-up from the conventional flask or plate method. Optimized production yielded greater than 10(13) vector genomes per bottle and was as cost effective as published protocols using plates. Successful vector production by this method was dependent on optimization of transfection by calcium phosphate precipitation, of monitoring of cell growth (by measurement of glucose consumption), of cell culture conditions, and CO2/air exchange with the culture vessel.
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159
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Cao L, During M, Xiao W. Replication competent helper functions for recombinant AAV vector generation. Gene Ther 2002; 9:1199-206. [PMID: 12215886 PMCID: PMC2638078 DOI: 10.1038/sj.gt.3301710] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2001] [Accepted: 02/11/2002] [Indexed: 11/09/2022]
Abstract
Adeno-associated virus (AAV) is a promising gene transfer vector tested in both animal studies and human clinical trials. However, current production methods are generally inefficient and require improvements to meet the increasing clinical need for economical, high titer and high quality rAAV vectors. The inefficiency of the current systems largely arises from the AAV helper function, which contains only the AAV coding region but lacks inverted terminal repeats. The terminal repeats were originally removed to prevent replication competent AAV contamination. Here we designed a novel and highly efficient rAAV helper function containing AAV terminal repeats. The new helper function not only mimics the wild-type AAV growth as it replicates along with the vector plasmid, but also restores the cis regulating function of the AAV terminal repeats. Addition of heterologous introns to the helper genome and use of a mutant AAV terminal repeat defective in packaging effectively controls the contamination of replication competent AAV particles. This new strategy also performs better in AAV producing cell lines than those based on non-replicating AAV rep and cap genome.
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160
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Hryciw T, Tang M, Fontanie T, Xiao W. MMS1 protects against replication-dependent DNA damage in Saccharomyces cerevisiae. Mol Genet Genomics 2002; 266:848-57. [PMID: 11810260 DOI: 10.1007/s00438-001-0605-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2001] [Accepted: 10/04/2001] [Indexed: 11/24/2022]
Abstract
A series of yeast mutants were isolated that are sensitive to killing by the monofunctional DNA-alkylating agent methyl methanesulfonate (MMS) but not by UV or X-radiation. We have cloned and characterized one of the corresponding genes, MMS1, and show that the mms1 Delta mutant is dramatically sensitive to killing by MMS and mildly sensitive to UV radiation. mms1 Delta mutants display an elevated level of spontaneous DNA damage and genomic instability. Furthermore, the mms1 Delta cells are sensitive to killing by conditions that induce replication-dependent double-strand breaks, such as treatment with camptothecin, and incubation of a cdc2-2 strain at the restrictive temperature. rad52 Delta is epistatic to mms1 Delta for MMS and camptothecin sensitivity, indicating that Mms1 acts in concert with Rad52. However, unlike mutants of the RAD52 group, mms1 Delta cells are not sensitive to gamma-rays, which induce double-strand breaks independently of DNA replication. Together these results suggest a role for an Mms1-dependent, Rad52-mediated, pathway in protecting cells against replication-dependent DNA damage.
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161
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Xiao W, Chow BL, Hanna M, Doetsch PW. Deletion of the MAG1 DNA glycosylase gene suppresses alkylation-induced killing and mutagenesis in yeast cells lacking AP endonucleases. Mutat Res 2001; 487:137-47. [PMID: 11738940 DOI: 10.1016/s0921-8777(01)00113-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
DNA base excision repair (BER) is initiated by DNA glycosylases that recognize and remove damaged bases. The phosphate backbone adjacent to the resulting apurinic/apyrimidinic (AP) site is then cleaved by an AP endonuclease or glycosylase-associated AP lyase to invoke subsequent BER steps. We have used a genetic approach in Saccharomyces cerevisiae to address whether AP sites are blocks to DNA replication and the biological consequences if AP sites persist in the genome. We found that yeast cells deficient in the two AP endonucleases (apn1 apn2 double mutant) are extremely sensitive to killing by methyl methanesulfonate (MMS), a model DNA alkylating agent. Interestingly, this sensitivity can be reduced up to 2500-fold by deleting the MAG1 3-methyladenine DNA glycosylase gene, suggesting that Mag1 not only removes lethal base lesions, but also benign lesions and possibly normal bases, and that the resulting AP sites are highly toxic to the cells. This rescuing effect appears to be specific for DNA alkylation damage, since the mag1 mutation reduces killing effects of two other DNA alkylating agents, but does not alter the sensitivity of apn cells to killing by UV, gamma-ray or H(2)O(2). Our mutagenesis assays indicate that nearly half of spontaneous and almost all MMS-induced mutations in the AP endonuclease-deficient cells are due to Mag1 DNA glycosylase activity. Although the DNA replication apparatus appears to be incapable of replicating past AP sites, Polzeta-mediated translesion synthesis is able to bypass AP sites, and accounts for all spontaneous and MMS-induced mutagenesis in the AP endonuclease-deficient cells. These results allow us to delineate base lesion flow within the BER pathway and link AP sites to other DNA damage repair and tolerance pathways.
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162
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Liu X, Fu H, Yang L, Huang M, Xiao W, Wang Y. [Changes of the expression of integrin alpha6beta1 and the activity of focal adhesion kinase in the liver sinusoidal endothelial cell in experimental fibrotic rats]. ZHONGHUA GAN ZANG BING ZA ZHI = ZHONGHUA GANZANGBING ZAZHI = CHINESE JOURNAL OF HEPATOLOGY 2001; 9:349-51. [PMID: 11782303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To investigate the expression of integrin alpha(6)beta(1) and the activity of focal adhesion kinase (FAK) in liver sinusoidal endothelial cells (SECs) from experimental fibrotic rats induced by CCl(4). METHODS By in situ collagenase perfusion and two-step Percoll gradient centrifugation, SECs were isolated and cultured from normal and CCl(4) -treated Wistar rats. The expression of integrin alpha(6)beta(1) was determined by cell-ELISA, and the activity of FAK was assessed by immunoprecipitation-tyrosine kinase assay. RESULTS The integrin alpha(6)beta(1) was almost absent in the normal SECs and was up-regulated during the fibrotic process; SECs from experimental fibrotic rats possessed higher expression level of integrin alpha(6)beta(1) than normal SECs (P<0.05). The FAK activity in SECs from experimental fibrotic rats increased significantly as compared with the normal controls (P<0.05). CONCLUSIONS The expression of integrin alpha(6)beta(1) on SECs and the increase of FAK in SECs may be important in the phenotype and function changes of SECs during hepatic fibrogenesis.
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163
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Premstaller A, Xiao W, Oberacher H, O'Keefe M, Stern D, Willis T, Huber CG, Oefner PJ. Temperature-modulated array high-performance liquid chromatography. Genome Res 2001; 11:1944-51. [PMID: 11691859 PMCID: PMC311160 DOI: 10.1101/gr.200401] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2001] [Accepted: 07/31/2001] [Indexed: 11/24/2022]
Abstract
Using novel monolithic poly(styrene-divinylbenzene) capillary columns with an internal diameter of 0.2 mm, we demonstrate for the first time the feasibility of constructing high-performance liquid chromatography arrays for the detection of mutations by heteroduplex analysis under partially denaturing conditions. In one embodiment, such an array can be used to analyze one sample simultaneously at different temperatures to maximize the detection of mutations in DNA fragments containing multiple discrete melting domains. Alternatively, one may inject different samples onto columns kept at the same effective temperature. Further improvements in throughput can be obtained by means of laser-induced fluorescence detection and the differential labeling of samples with up to four different fluorophores. Major advantages of monolithic capillary high-performance liquid chromatographic arrays over their capillary electrophoretic analogs are the chemical inertness of the poly(styrene-divinylbenzene) stationary phase, the physical robustness of the column bed due to its covalent linkage to the inner surface of the fused silica capillary, and the feasibility to modify the stationary phase thereby allowing the separation of compounds not only on the principle of size exclusion, but also adsorption, distribution, and ion exchange. Analyses times are on the order of a few minutes and turnaround time is extremely short as there is no need for the replenishment of the separation matrix between runs.
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164
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Zhu Y, Xiao W. Two alternative cell cycle checkpoint pathways differentially control DNA damage-dependent induction of MAG1 and DDI1 expression in yeast. Mol Genet Genomics 2001; 266:436-44. [PMID: 11713673 DOI: 10.1007/s004380100538] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2001] [Accepted: 06/04/2001] [Indexed: 10/28/2022]
Abstract
Eukaryotic cells respond to DNA damage by activating damage checkpoint pathways, which arrest cell cycle progression and induce gene expression. In order to understand how damage checkpoints control the expression of DNA damage-inducible genes, the transcript level of two closely clustered genes, MAG1 and DDI1, was examined in a number of checkpoint mutants. We previously reported that MAG1 induction was abolished in pol2 and rad53 mutants, but not in the mec1-1 mutant. In this study, we found that mec1Delta and dun1Delta null mutants were defective in MAG1 induction, suggesting that MAG1 shares a common regulatory pathway with the RNR1,2,3,4 genes, which are also regulated by the POL2-MEC1-RAD53-DUN1 checkpoint pathway, and that the mec1-1 mutation probably represents a separation-of-function mutation. However, MAG1 is not activated in precisely the same way as the RNR genes, since mutations in CRT1, TUP1 and SSN6, which encode repressors of RNR genes, did not affect basal or induced expression of MAG1. In contrast, the DDI1 transcript level was not affected by any of the above checkpoint mutations. Interestingly, simultaneous inactivation of RAD53 or DUN1 with PDS1, a newly identified checkpoint gene, resulted in severe down-regulation of DDI1 expression, suggesting that DDI1 is controlled by two damage checkpoint pathways, one mediated by POL2-MEC1-RAD53-DUN1 and the other by CHK1-PDS1. On the other hand, deletion of TEL1, a structural homologue of MEC1, did not affect expression of MAG1, DDI1 or RNR3, suggesting that TEL1 plays no role in induction by DNA damage. Based on these and previous studies, we present a model for the role of checkpoint genes in transcriptional regulation in response to DNA damage.
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165
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Xiao W. [History of modern obstetrics in western medicine in china]. ZHONGHUA YI SHI ZA ZHI (BEIJING, CHINA : 1980) 2001; 25:204-10. [PMID: 11613576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
This paper deals with the developmental history of western medicine in China. Due to the hindrance of feudal conception, modern obstetrics began rather late. The first Chinese obstetrical ward was established in Fujian Province in 1911. Before 1930, the Chinese maternal and neonatal mortality rates were 4-5 times higher than that of European and American countries. After 1930, "Education of Midwives" commenced, including the founding of midwifery school, antenatal care, pelvie measurements, improvements of the diagnosis for pathological pregnancy, management of complications during pregnancy. All these have improved modern obstetrics in China and laid down the foundation for its development after 1949.
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166
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Xiao W. [Modern history of gynecology in China]. ZHONGHUA YI SHI ZA ZHI (BEIJING, CHINA : 1980) 2001; 25:129-33. [PMID: 11613559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Dealing with the modern history (1850-1949) of the establishment and development of Gynecology in China, this paper claims that the sprouting period covers the time prior to 1899. After 1991 Gynecology developed steadily due to the advancement of surgery, pathology, bacteriology and anesthesiology. During this period, there were definite improvements in Gynecology diagnosis, treatment of pelvic inflammation and gynecological endocrinology.
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167
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Hodge DR, Xiao W, Clausen PA, Heidecker G, Szyf M, Farrar WL. Interleukin-6 regulation of the human DNA methyltransferase (HDNMT) gene in human erythroleukemia cells. J Biol Chem 2001; 276:39508-11. [PMID: 11551897 DOI: 10.1074/jbc.c100343200] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Methylation of mammalian DNA by the DNA methyltransferase enzyme (dnmt-1) at CpG dinucleotide sequences has been recognized as an important epigenetic control mechanism in regulating the expression of cellular genes (Yen, R. W., Vertino, P. M., Nelkin, B. D., Yu, J. J., el-Deiry, W., Cumaraswamy, A., Lennon, G. G., Trask, B. J., Celano, P., and Baylin, S. B. (1992) Nucleic Acids Res. 20, 2287-2291; Ramchandani, S., Bigey, P., and Szyf, M. (1998) Biol. Chem. 379, 535-5401). Here we show that interleukin (IL)-6 regulates the methyltransferase promoter and resulting enzyme activity, which requires transcriptional activation by the Fli-1 transcription factor (Spyropoulos, D. D., Pharr, P. N., Lavenburg, K. R., Jackers, P., Papas, T. S., Ogawa, M., and Watson, D. K. (1998) Mol. Cell. Biol. 15, 5643-5652). The data suggest that inflammatory cytokines such as IL-6 may exert many epigenetic changes in cells via the regulation of the methyltransferase gene. Furthermore, IL-6 regulation of transcription factors like Fli-1, which can help to direct cells along opposing differentiation pathways, may in fact be reflected in part by their ability to regulate the methylation of cellular genes.
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168
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McKenna S, Spyracopoulos L, Moraes T, Pastushok L, Ptak C, Xiao W, Ellison MJ. Noncovalent interaction between ubiquitin and the human DNA repair protein Mms2 is required for Ubc13-mediated polyubiquitination. J Biol Chem 2001; 276:40120-6. [PMID: 11504715 DOI: 10.1074/jbc.m102858200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ubiquitin-conjugating enzyme variants share significant sequence similarity with typical E2 (ubiquitin-conjugating) enzymes of the protein ubiquitination pathway but lack their characteristic active site cysteine residue. The MMS2 gene of Saccharomyces cerevisiae encodes one such ubiquitin-conjugating enzyme variant that is involved in the error-free DNA postreplicative repair pathway through its association with Ubc13, an E2. The Mms2-Ubc13 heterodimer is capable of linking ubiquitin molecules to one another through an isopeptide bond between the C terminus and Lys-63. Using highly purified components, we show here that the human forms of Mms2 and Ubc13 associate into a heterodimer that is stable over a range of conditions. The ubiquitin-thiol ester form of the heterodimer can be produced by the direct activation of its Ubc13 subunit with E1 (ubiquitin-activating enzyme) or by the association of Mms2 with the Ubc13-ubiquitin thiol ester. The activated heterodimer is capable of transferring its covalently bound ubiquitin to Lys-63 of an untethered ubiquitin molecule, resulting in diubiquitin as the predominant species. In (1)H (15)N HSQC ((1)H (15)N heteronuclear single quantum coherence) NMR experiments, we have mapped the surface determinants of tethered and untethered ubiquitin that interact with Mms2 and Ubc13 in both their monomeric and dimeric forms. These results have identified a surface of untethered ubiquitin that interacts with Mms2 in the monomeric and heterodimeric form. Furthermore, the C-terminal tail of ubiquitin does not participate in this interaction. These results suggest that the role of Mms2 is to correctly orient either a target-bound or untethered ubiquitin molecule such that its Lys-63 is placed proximally to the C terminus of the ubiquitin molecule that is linked to the active site of Ubc13.
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Liu X, Huang M, Peng X, Xiao W, Wang Y. [The role of YIGSR and RGD peptides in regulating fenestrae of sinusoidal endothelial cells]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 2001; 32:338-40, 375. [PMID: 12536556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
OBJECTIVE To investigate the effects of Tye-Ile-Gly-Ser-Arg (YIGSR) and Arg-Gly-Asp (RGD) polypeptides on the fenestrae of the liver sinusoidal endothelial cells (SECs). METHODS By in situ collagenase perfusion and two-step percoll gradient centrifugation, SECs were isolated from normal Wistar rats and cultured on collagen type I or laminin-coated coverslips. The population of SECs fenestrae and their diameters were observed using scanning electron microscopical technique; and the synthesis of collagen type IV in SECs was assessed by radio-immunoassay (RIA). RESULTS The average number of fenestrae and their diameter in the SECs cultured on laminin-coated coverslips were significantly lower than those on collagen type I-coated coverslips. After the treatment with YIGSR pentapeptides (50 micrograms/ml) and RGD tripeptides (50 micrograms/ml) together for 48 hrs, the number and diameters of fenestrae in the SECs that grew on laminin-coated coverslips increased markedly. Meanwhile, the YIGSR and RGD peptides could significantly decrease the synthesis of collagen type IV in SECs that grew on laminin-coated coverslips. CONCLUSION The results suggested that the YIGSR and RGD polypeptides may have an important role in regulating the morphology and function of SECs.
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170
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Xiao W, Wang Y, Liu X. [The coordinated expression of laminin and its integrin receptor in hepatic sinusoidal capillarization]. ZHONGHUA NEI KE ZA ZHI 2001; 40:618-20. [PMID: 11758244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To explore the expression of laminin and its integrin receptor alpha 6 in sinusoidal capillaration. METHODS The rat hepatic fibrosis model was established by injection carbon tetrachloride subcutaneously. Liver sections were examined by scanning electron microscopy and special staining. Then expressions of laminin and integrin alpha 6 subunit were observed by immunohistochemistry and dot immuno-blotting. RESULTS The pathologic character of hepatic fibrosis-sinusoidal capillaration was observed. Sinusoidal capillaration is characterized by defenestration of sinusoidal endothelial cells (SEC) and basement membrane forming and phenotype transformation. By immunohistochemistry staining. The deposition of laminin surrounding sinusoids according to fibrosis stage was 0, 1.92%, 6.02%, 9.68%, 14.14% respectively, statistically different from each other (P < 0.05). In normal rat no expression of integrin alpha 6 were observed in SEC membranes. When capillaration integrin alpha 6 was detected in a continuous pattern along the sinusoidal in accordance with laminin assembly. The content of integrin alpha 6 in fibrotic liver tissues were significantly higher than in normal liver tissues as measured by dot immuno-blotting (P < 0.05). CONCLUSIONS During fibrogenesis laminin continuously accumulate in liver tissues and form basement membrane resulting in sinusoidal capillaration, meanwhile are company with induced expression of LN-binding-integrin alpha 6 on SEC membranes. These results suggest that coordinated expression of laminin and laminin-binding-integrin might be important in pathogenesis of sinusoidal capillaration and hepatic fibrosis.
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Wang LH, Yang XY, Mihalic K, Xiao W, Li D, Farrar WL. Activation of estrogen receptor blocks interleukin-6-inducible cell growth of human multiple myeloma involving molecular cross-talk between estrogen receptor and STAT3 mediated by co-regulator PIAS3. J Biol Chem 2001; 276:31839-44. [PMID: 11429412 DOI: 10.1074/jbc.m105185200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Estrogen receptors (ERs)(1) highly expressed by multiple myeloma (MM) cells and stimulation of estrogenic ligands leads to cell apoptosis. Interleukin (IL)-6 is a major growth factor in the pathogenesis of MM. However, little is known concerning the molecular consequences of ER activation on IL-6-regulated MM cell growth. Here we show that the ER agonist 17 beta-estradiol completely abolished IL-6-inducible MM cell proliferation. By contrast, the ER antagonist ICI 182,780 overcame the inhibitory effect of estrogen. Estrogen blocked STAT3 DNA binding and transactivation but failed to affect the mRNA expression of IL-6 receptor chains or activation of JAK2 and STAT3. Estrogen-activated ER did not associate directly with STAT3. Estrogen induced the mRNA expression of PIAS3 (protein inhibitor of activated STAT3) and increased PIAS3 physical association with STAT3, suggesting a possible mechanism of STAT3 inhibition requiring PIAS3 as a co-regulator modulating the cross-talk between ER and STAT3. These data directly demonstrate STAT3 to be a molecular participant in ER inhibition of the IL-6 signaling pathway in human MM cells and provides the molecular basis for the potential use of estrogenic ligands in the treatment of MM or other tumors where IL-6 has an autocrine or paracrine role.
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Abstract
DNA postreplication repair (PRR) is defined as an activity to convert DNA damage-induced single-stranded gaps into large molecular weight DNA without actually removing the replication-blocking lesions. In bacteria such as Escherichia coli, this activity requires RecA and the RecA-mediated SOS response and is accomplished by recombination and mutagenic translesion DNA synthesis. Eukaryotic cells appear to share similar DNA damage tolerance pathways; however, some enzymes required for PRR in eukaryotes are rather different from those of prokaryotes. In the yeast Saccharomyces cerevisiae, PRR is centrally controlled by RAD6 and RAD18, whose products form a stable complex with single-stranded DNA-binding, ATPase and ubiquitin-conjugating activities. PRR can be further divided into translesion DNA synthesis and error-free modes, the exact molecular events of which are largely unknown. This error-free PRR is analogous to DNA damage-avoidance as defined in mammalian cells, which relies on recombination processes. Two possible mechanisms by which recombination participate in PRR to resolve the stalled replication folk are discussed. Recombination and PRR are also genetically regulated by a DNA helicase and are coupled to the cell-cycle. The PRR processes appear to be highly conserved within eukaryotes, from yeast to human.
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173
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Xiao D, Wang K, Xiao W. Synchronous fluorescence and absorbance dynamic liquid drop sensor for cr(VI) determination at the femtomole level. Analyst 2001; 126:1387-92. [PMID: 11534611 DOI: 10.1039/b009217g] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel synchronous fluorimetric and absorptiometric technique based on dynamic liquid drops coupled with flow injection is described for the determination of chromium(VI) in aqueous solutions. Drops formed continuously at the end of a quartz capillary tube serve as reactor and optical cell. The reaction between chromium(VI) and 3,3',5,5'-tetramethylbenzidine dichloride (TMB-d) results in a significant decrease in fluorescence and transmitted light intensity, proportional to the logarithm of the concentration of chromium(VI). The transmitted light and fluorescence emission are detected in counter and perpendicular positions of the excitation light by a photomultipler tube and photodiode, respectively. In HCl-NaOAc buffer solution (pH 3.29), the sensor has a wide linear calibration range of 2 x 10(-8)-1 x 10(-4) mol l(-1) chromium(VI) with an absolute mass detection limit of 12.88 fmol.
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174
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Moraes TF, Edwards RA, McKenna S, Pastushok L, Xiao W, Glover JN, Ellison MJ. Crystal structure of the human ubiquitin conjugating enzyme complex, hMms2-hUbc13. NATURE STRUCTURAL BIOLOGY 2001; 8:669-73. [PMID: 11473255 DOI: 10.1038/90373] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ubiquitin conjugating enzyme complex Mms2-Ubc13 plays a key role in post-replicative DNA repair in yeast and the NF-kappaB signal transduction pathway in humans. This complex assembles novel polyubiquitin chains onto yet uncharacterized protein targets. Here we report the crystal structure of a complex between hMms2 (Uev1) and hUbc13 at 1.85 A resolution and a structure of free hMms2 at 1.9 A resolution. These structures reveal that the hMms2 monomer undergoes a localized conformational change upon interaction with hUbc13. The nature of the interface provides a physical basis for the preference of Mms2 for Ubc13 as a partner over a variety of other structurally similar ubiquitin-conjugating enzymes. The structure of the hMms2-hUbc13 complex provides the conceptual foundation for understanding the mechanism of Lys 63 multiubiquitin chain assembly and for its interactions with the RING finger proteins Rad5 and Traf6.
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175
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Xiao W, Wang Z, Li Z, Feng S. [Studies on the genotoxic effects of acrylonitrile]. WEI SHENG YAN JIU = JOURNAL OF HYGIENE RESEARCH 2001; 30:239-40. [PMID: 12561525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The effect of acrylonitrile (AN) on the reproduction was investigated in 341 male and 365 female exposed workers, 384 male and 438 female unexposed controls by questionnaires on the process of childbearing and the outcome of child birth. The results showed that AN caused menstrual disorder and dysgenesis in exposed female workers and the wife of exposed male workers. It is concluded that AN is harmful to the reproduction of exposed male and female workers.
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