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Abstract
Ostracism is such a widely used and powerful tactic that the authors tested whether people would be affected by it even under remote and artificial circumstances. In Study 1, 1,486 participants from 62 countries accessed the authors' on-line experiment on the Internet. They were asked to use mental visualization while playing a virtual tossing game with two others (who were actually computer generated and controlled). Despite the minimal nature of their experience, the more participants were ostracized, the more they reported feeling bad, having less control, and losing a sense of belonging. In Study 2, ostracized participants were more likely to conform on a subsequent task. The results are discussed in terms of supporting K. D. Williams's (1997) need threat theory of ostracism.
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Clinical Trial |
25 |
1084 |
2
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Williams KD, Cheung CK, Choi W. Cyberostracism: effects of being ignored over the Internet. J Pers Soc Psychol 2001. [PMID: 11079239 DOI: 10.1037//0022-3514.79.5.748] [Citation(s) in RCA: 342] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ostracism is such a widely used and powerful tactic that the authors tested whether people would be affected by it even under remote and artificial circumstances. In Study 1, 1,486 participants from 62 countries accessed the authors' on-line experiment on the Internet. They were asked to use mental visualization while playing a virtual tossing game with two others (who were actually computer generated and controlled). Despite the minimal nature of their experience, the more participants were ostracized, the more they reported feeling bad, having less control, and losing a sense of belonging. In Study 2, ostracized participants were more likely to conform on a subsequent task. The results are discussed in terms of supporting K. D. Williams's (1997) need threat theory of ostracism.
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Research Support, Non-U.S. Gov't |
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342 |
3
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Abstract
Findings described in this report are for 6,763 white male Seventh-day Adventists who completed a dietary questionnaire in 1960. Between 1960 and 1980 mortality data were collected on cohort members. Overweight men had a significantly higher risk of fatal prostate cancer than men near their desirable weight. The predicted relative risk of fatal prostate cancer was 2.5 for overweight men. Suggestive positive associations were also seen between fatal prostate cancer and the consumption of milk, cheese, eggs, and meat. There was an orderly dose-response between each of the four animal products and risk. The predicted relative risk of fatal prostate cancer was 3.6 for those who heavily consumed all four animal products. The results of this study and others suggest that animal product consumption and obesity may be risk factors for fatal prostate cancer.
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41 |
248 |
4
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Choi W, Dean RA. The adenylate cyclase gene MAC1 of Magnaporthe grisea controls appressorium formation and other aspects of growth and development. THE PLANT CELL 1997; 9:1973-83. [PMID: 9401122 PMCID: PMC157051 DOI: 10.1105/tpc.9.11.1973] [Citation(s) in RCA: 222] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Magnaporthe grisea, the causal agent of rice blast disease, differentiates a specialized infection structure called an appressorium that is crucial for host plant penetration. Previously, it was found that cAMP regulates appressorium formation. To further understand the cellular mechanisms involved in appressorium formation, we have cloned a gene (MAC1) encoding adenylate cyclase, a membrane-bound enzyme that catalyzes the production of cAMP from ATP, by using a polymerase chain reaction-based strategy. The entire gene was isolated and subcloned from a large insert bacterial artificial chromosome library. Sequence characterization showed that MAC1 has a high degree of identity with other adenylate cyclase genes from several filamentous fungi as well as yeasts. Gene deletion resulted in reduced vegetative growth, conidiation, and conidial germination. Transformants lacking MAC1 were unable to form appressoria on an inductive surface and were unable to penetrate susceptible rice leaves. mac1- transformants were also sterile and produced no perithecia. Appressorium formation was restored in the presence of exogenous cAMP derivatives. These results confirm that cell signaling involving cAMP plays a central role in the development and pathogenicity of M. grisea.
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research-article |
28 |
222 |
5
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McBride ML, Gallagher RP, Thériault G, Armstrong BG, Tamaro S, Spinelli JJ, Deadman JE, Fincham S, Robson D, Choi W. Power-frequency electric and magnetic fields and risk of childhood leukemia in Canada. Am J Epidemiol 1999; 149:831-42. [PMID: 10221320 DOI: 10.1093/oxfordjournals.aje.a009899] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In a case-control study of childhood leukemia in relation to exposure to power-frequency electric and magnetic fields (EMF), 399 children resident in five Canadian provinces who were diagnosed at ages 0-14 years between 1990 and 1994 (June 1995 in British Columbia and Quebec) were enrolled, along with 399 controls. Exposure assessment included 48-hour personal EMF measurement, wire coding and magnetic field measurements for subjects' residences from conception to diagnosis/reference date, and a 24-hour magnetic field bedroom measurement. Personal magnetic fields were not related to risk of leukemia (adjusted odds ratio (OR) = 0.95, p for trend = 0.73) or acute lymphatic leukemia (OR = 0.93, p for trend = 0.64). There were no clear associations with predicted magnetic field exposure 2 years before the diagnosis/reference date or over the subject's lifetime or with personal electric field exposure. A statistically nonsignificant elevated risk of acute lymphatic leukemia was observed with very high wiring configurations among residences of subjects 2 years before the diagnosis/reference date (OR = 1.72 compared with underground wiring, 95% confidence interval 0.54-5.45). These results provide little support for a relation between power-frequency EMF exposure and risk of childhood leukemia.
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26 |
169 |
6
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Kim KM, Chun SB, Koo MS, Choi WJ, Kim TW, Kwon YG, Chung HT, Billiar TR, Kim YM. Differential regulation of NO availability from macrophages and endothelial cells by the garlic component S-allyl cysteine. Free Radic Biol Med 2001; 30:747-56. [PMID: 11275474 DOI: 10.1016/s0891-5849(01)00460-9] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Garlic has been used as a traditional medicine for prevention and treatment of cardiovascular diseases. However, the molecular mechanism of garlic's pharmacological action has not been clearly elucidated. We examined here the effect of garlic extract and its major component, S-allyl cysteine (SAC), on nitric oxide (NO) production by macrophages and endothelial cells. The present study demonstrates that these reagents inhibited NO production through the suppression of iNOS mRNA and protein expression in the murine macrophage cell line RAW264.7, which had been stimulated with LPS and IFNgamma. The garlic extract also inhibited NO production in peritoneal macrophages, rat hepatocytes, and rat aortic smooth muscle cells stimulated with LPS plus cytokines, but it did not inhibit NO production in iNOS-transfected AKN-1 cells or iNOS enzyme activity. These reagents suppressed NF-kappaB activation and murine iNOS promoter activity in LPS and IFNgamma-stimulated RAW264.7 cells. In contrast, these reagents significantly increased cGMP production by eNOS in HUVEC without changes in activity, protein levels, and cellular distribution of eNOS. Finally, garlic extract and SAC both suppressed the production of hydroxyl radical, confirming their antioxidant activity. These data demonstrate that garlic extract and SAC, due to their antioxidant activity, differentially regulate NO production by inhibiting iNOS expression in macrophages while increasing NO in endothelial cells. Thus, this selective regulation may contribute to the anti-inflammatory effect and prevention of atherosclerosis by these reagents.
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MESH Headings
- Animals
- Aorta
- Cell Line
- Cells, Cultured
- Cyclic GMP/biosynthesis
- Cysteine/analogs & derivatives
- Cysteine/pharmacology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Female
- Garlic/chemistry
- Gene Expression/drug effects
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- Humans
- Interferon-gamma/pharmacology
- Lipopolysaccharides/pharmacology
- Macrophages/drug effects
- Macrophages/metabolism
- Macrophages, Peritoneal/drug effects
- Macrophages, Peritoneal/metabolism
- Male
- Mice
- Mice, Inbred BALB C
- Muscle, Smooth
- NF-kappa B/antagonists & inhibitors
- Nitric Oxide/biosynthesis
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase Type II
- Plants, Medicinal
- Promoter Regions, Genetic
- RNA, Messenger/analysis
- Rats
- Rats, Sprague-Dawley
- Umbilical Veins
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149 |
7
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Cho Y, Choi W, Lee CH, Hyeon T, Lee HI. Visible light-induced degradation of carbon tetrachloride on dye-sensitized TiO2. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:966-970. [PMID: 11351543 DOI: 10.1021/es001245e] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study investigated an application of TiO2 photocatalyst sensitized with tris(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium-(II) complex to CCl4 degradation under visible light irradiation. By injecting electrons from the photoexcited sensitizer to the conduction band, the sensitized TiO2 degraded CCl4 under the irradiation of lambda > 420 nm. The quantum yield of CCl4 dechlorination was about 10(-3). The dechlorination rate of CCl4 was reduced in the presence of dissolved O2 due to its competition for conduction band electrons. The photolysis rate was dependent on pH due to the strong pH dependence of the sensitizer adsorption on TiO2 surface with a maximum degradation rate achieved at pH approximately 3. A two-site Langmurian model successfully described the adsorption of the sensitizer on TiO2 particles. The monolayer coverage was achieved at the added sensitizer concentration of 10 microM at [TiO2] = 0.5 g/L. However, the photolysis rate of CCl4 showed a maximum at a sensitizer surface coverage of 0.3 monolayer. Since the photoinduced electron injection gradually depleted active sensitizer molecules on TiO2, sacrificial electron donors to regenerate the sensitizer were sought. 2-Propanol as an electron donor was efficient in the present RuIIL3/TiO2/CCl4 system, which showed no sign of deceleration in the dechlorination rate up to 6 h of irradiation.
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24 |
139 |
8
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Ahn JK, Chebotaryov S, Choi JH, Choi S, Choi W, Choi Y, Jang HI, Jang JS, Jeon EJ, Jeong IS, Joo KK, Kim BR, Kim BC, Kim HS, Kim JY, Kim SB, Kim SH, Kim SY, Kim W, Kim YD, Lee J, Lee JK, Lim IT, Ma KJ, Pac MY, Park IG, Park JS, Park KS, Shin JW, Siyeon K, Yang BS, Yeo IS, Yi SH, Yu I. Observation of reactor electron antineutrinos disappearance in the RENO experiment. PHYSICAL REVIEW LETTERS 2012; 108:191802. [PMID: 23003027 DOI: 10.1103/physrevlett.108.191802] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Indexed: 06/01/2023]
Abstract
The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six 2.8 GW(th) reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is 0.920±0.009(stat)±0.014(syst). From this deficit, we determine sin(2)2θ(13)=0.113±0.013(stat)±0.019(syst) based on a rate-only analysis.
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13 |
105 |
9
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Kahn HA, Phillips RL, Snowdon DA, Choi W. Association between reported diet and all-cause mortality. Twenty-one-year follow-up on 27,530 adult Seventh-Day Adventists. Am J Epidemiol 1984; 119:775-87. [PMID: 6720674 DOI: 10.1093/oxfordjournals.aje.a113798] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
This report examines the association between mortality from all causes during a 21-year period and frequency of consumption of 28 specific foods among 27,530 adult California members of the Seventh-Day Adventist Church. Food consumption was measured at the beginning of the study (1960) by a self-administered questionnaire. Deaths were identified by computer-assisted matching of study subjects to the file of death certificates for all deaths that occurred in California during 1960-1980. All-cause mortality showed a significant negative association with green salad consumption and a significant positive association with consumption of eggs and meat. For green salad and eggs, the association was stronger for women; for meat, the association was stronger for men. All the observed associations were adjusted for age, sex, smoking history, history of major chronic disease, and age at initial exposure to the Adventist Church.
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41 |
96 |
10
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Park CH, Kim SH, Choi W, Lee YJ, Kim JS, Kang SS, Suh YH. Novel anticholinesterase and antiamnesic activities of dehydroevodiamine, a constituent of Evodia rutaecarpa. PLANTA MEDICA 1996; 62:405-409. [PMID: 8923803 DOI: 10.1055/s-2006-957926] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To find a new compound with antiamnesic activity, we screened 29 natural products for their abilities to inhibit acetylcholinesterase and reverse scopolamine-induced amnesia. Among the plants tested Evodia rutaecarpa Bentham showed a strong inhibitory effect on acetylcholinesterase in vitro and an anti-amnesic effect in vivo. By sequential fractionation of E. rutaecarpa, the active component was finally identified as dehydroevodiamine hydrochloride (DHED). DHED inhibited acetylcholinesterase activity in a dose-dependent and non-competitive manner. The IC50 value of DHED is 37.8 microM. A single administration of DHED to rats (6.25 mg/kg) significantly reversed the scopolamine-induced memory impairment in a passive avoidance test. The antiamnesic effect of DHED was more potent than that of tacrine which is the only drug for Alzheimer's disease approved by FDA. This potent antiamnesic effect of DHED was thought to be due to the combined effects of acetylcholinesterase inhibition and the known cerebral blood flow enhancement. These results indicate that DHED has novel anti-cholinesterase and antiamnesic activities and might have therapeutic potential in various disorders including Alzheimer's disease.
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Comparative Study |
29 |
93 |
11
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Choi W, Hoffmann MR. Photoreductive Mechanism of CCl4 Degradation on TiO2 Particles and Effects of Electron Donors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 1995; 29:1646-1654. [PMID: 22276890 DOI: 10.1021/es00006a031] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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30 |
89 |
12
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Kaldor JM, Day NE, Bell J, Clarke EA, Langmark F, Karjalainen S, Band P, Pedersen D, Choi W, Blair V. Lung cancer following Hodgkin's disease: a case-control study. Int J Cancer 1992; 52:677-81. [PMID: 1428226 DOI: 10.1002/ijc.2910520502] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
It is recognized that survivors of Hodgkin's disease are at a substantially increased risk of lung cancer. A collaborative group of population-based cancer registries and major treatment centers carried out a case-control study, in which 98 cases of lung cancer were identified in patients who had survived at least 1 year following a diagnosis of Hodgkin's disease. A total of 259 matched controls were selected from patients with Hodgkin's disease who did not develop subsequent lung cancer, and for both cases and controls detailed information was abstracted from medical records concerning stage and treatment of Hodgkin's disease. Patients treated with chemotherapy alone had about twice the risk of developing lung cancer than those treated by radiotherapy alone or both modalities. There was no increase in risk with cumulative number of cycles of chemotherapy. Among patients treated with radiotherapy alone, there was an increase in risk related to estimated radiation dose to the lung. There was also a strong association between cigarette smoking and the risk of lung cancer. The finding of a higher risk following chemotherapy than following radiotherapy was unexpected, but could not be explained by any identified methodological flaws. A plausible inference from the study is that all forms of Hodgkin's disease therapy are carcinogenic to the lung and that, in particular, chemotherapy is associated with an increase in risk which is at least comparable to and perhaps higher than the risk produced by radiotherapy.
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33 |
74 |
13
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Cho SG, Kim MY, Kim HJ, Kim YS, Choi W, Shin SH, Hong KC, Kim YB, Lee JH, Suh CH. Chronic hepatitis: in vivo proton MR spectroscopic evaluation of the liver and correlation with histopathologic findings. Radiology 2001; 221:740-6. [PMID: 11719670 DOI: 10.1148/radiol.2213010106] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE To correlate the in vivo hydrogen 1 ((1)H) magnetic resonance (MR) spectroscopic features of the chronic hepatitis-involved liver with the histopathologic stages of fibrosis. MATERIALS AND METHODS Seventy-five patients with chronic hepatitis were examined with (1)H MR spectroscopy, which was performed in the right hepatic lobe. The peak areas of glutamine and glutamate complex (Glx), phosphomonoesters (PME), glycogen and glucose complex (Glyu), and lipid were measured on the liver spectra. The histopathologic features were correlated with the in vivo (1)H MR spectroscopic findings at each stage of chronic hepatitis. Fifteen healthy volunteers also were included as a control group. RESULTS (1)H MR spectroscopy depicted Glx, PME, Glyu, and lipid in all livers. In the normal livers, the calculated mean (+/- SD) relative metabolite-to-lipid ratios of Glx, PME, and Glyu were 0.14 +/- 0.04, 0.03 +/- 0.01, and 0.21 +/- 0.04, respectively. The mean value of each metabolite-to-lipid ratio was significantly different between all stages of chronic hepatitis, and with the exception of the mean ratio at the interval between stages 0 and 1 (P > .05), the mean value increased significantly with increasing stage (P < .05). A pronounced peak was demonstrated at 3.9-4.1 ppm at (1)H MR spectroscopy of all stages of chronic hepatitis except stage 0. CONCLUSION The increased Glx, PME, and Glyu levels relative to the lipid content with chronic hepatitis indicated the severity of fibrosis and thus were concordant with the histopathologic stages. In vivo (1)H MR spectroscopy might be a substitute for liver biopsy in the diagnosis and staging of chronic hepatitis.
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74 |
14
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Choi WJ, Cabib E. The use of divalent cations and pH for the determination of specific yeast chitin synthetases. Anal Biochem 1994; 219:368-72. [PMID: 8080094 DOI: 10.1006/abio.1994.1278] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Saccharomyces cerevisiae contains three chitin synthetases, Chs1, Chs2, and Chs3, performing different physiological functions but catalyzing the same reaction. It has been found that Ni2+ is a powerful inhibitor of Chs1 and Chs2 activity but has very little effect on the activity of Chs3, especially in the presence of Co2+. These results, together with the previous knowledge that Co2+ stimulates Chs2 and Chs3 but inhibits Chs1 and that the three synthetases differ in their pH optimum, have enabled us to formulate conditions for the specific determination of each synthetase in the presence of the others.
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Comparative Study |
31 |
63 |
15
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Cordier S, Monfort C, Filippini G, Preston-Martin S, Lubin F, Mueller BA, Holly EA, Peris-Bonet R, McCredie M, Choi W, Little J, Arslan A. Parental exposure to polycyclic aromatic hydrocarbons and the risk of childhood brain tumors: The SEARCH International Childhood Brain Tumor Study. Am J Epidemiol 2004; 159:1109-16. [PMID: 15191928 DOI: 10.1093/aje/kwh154] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Experimental evidence suggests that parental exposure to polycyclic aromatic hydrocarbons (PAH), which occurs primarily through tobacco smoke, occupational exposure, and air pollution, could increase the risk of cancer during childhood. Population-based case-control studies carried out in seven countries as part of the SEARCH Program compared data for 1,218 cases of childhood brain tumors and 2,223 controls (1976-1994). Parental occupational exposure to PAH during the 5-year period before birth was estimated with a job exposure matrix. Risk estimates were adjusted for child's age, sex, and study center. Paternal preconceptional occupational exposure to PAH was associated with increased risks of all childhood brain tumors (odds ratio (OR) = 1.3, 95% confidence interval: 1.1, 1.6) and astroglial tumors (OR = 1.4, 95% confidence interval: 1.1, 1.7). However, there was no trend of increasing risk with predicted level of exposure. Paternal smoking alone (OR = 1.4) was also associated with the risk of astroglial tumors in comparison with nonsmoking, non-occupationally-exposed fathers. Risks for paternal occupational exposure were higher, with (OR = 1.6) or without (OR = 1.7) smoking. Maternal occupational exposure to PAH before conception or during pregnancy was rare, and this exposure was not associated with any type of childhood brain tumor. This large study supports the hypothesis that paternal preconceptional exposure to PAH increases the risk of brain tumors in humans.
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21 |
60 |
16
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Choi WJ, Sburlati A, Cabib E. Chitin synthase 3 from yeast has zymogenic properties that depend on both the CAL1 and the CAL3 genes. Proc Natl Acad Sci U S A 1994; 91:4727-30. [PMID: 8197125 PMCID: PMC43861 DOI: 10.1073/pnas.91.11.4727] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In previous studies, chitin synthase 3 (Chs3), the enzyme responsible for synthesis of most of the chitin present in the yeast cell, was found to be inactivated by incubation with trypsin, in contrast to other yeast chitin synthases (Chs1 and Chs2), which are stimulated by this treatment (chitin synthase; UDP-N-acetyl-D-glucosamine:chitin 4-beta-N-acetylglucosaminyl-transferase, EC 2.4.1.16). It has now been found that the substrate UDPGlcNAc protects Chs3 against proteolytic inactivation. Treatment of Chs3-containing membranes with detergents drastically reduced the enzymatic activity. Activity could, however, be restored by subsequent incubation with trypsin or other proteases in the presence of UDPGlcNAc. Under such conditions, protease treatment stimulated activity as much as 10-fold. A change in divalent cation specificity after trypsin treatment suggests that the protease directly affects the enzyme molecule. Experiments with mutants in the three genes involved in Chs3 activity--CAL1, CAL2, and CAL3--showed that only CAL1 and CAL3 are required for the protease-elicited (zymogenic) activity. It is concluded that Chs3 is a zymogen and that the CAL2 product functions as its activator. The differences and possible similarities between Chs3 and the other chitin synthases are discussed.
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research-article |
31 |
58 |
17
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Chung S, Kim M, Choi W, Chung J, Lee K. Expression of translationally controlled tumor protein mRNA in human colon cancer. Cancer Lett 2000; 156:185-90. [PMID: 10880768 DOI: 10.1016/s0304-3835(00)00460-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The translationally controlled tumor protein (TCTP) was first identified as a tumor-associated protein. Here we described the expression profile of TCTP mRNA using a panel of normal human tissues. We also investigated the cell-cycle-dependent expression of the TCTP mRNA using synchronized cultures of Saccahromyces cerevisiae. The TCTP gene was constantly expressed through the yeast cell cycle. The expression of TCTP mRNA from three human colon carcinoma cell lines and their tumors xenografted in a nude mouse was studied. Our data imply that the TCTP is a housekeeping gene and that its deregulation may be involved in the tumor development of colon carcinoma.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/pathology
- Animals
- Biomarkers, Tumor
- Blotting, Northern
- Calcium-Binding Proteins/biosynthesis
- Calcium-Binding Proteins/genetics
- Cell Cycle/physiology
- Colonic Neoplasms/genetics
- Colonic Neoplasms/metabolism
- Colonic Neoplasms/pathology
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Mice
- Mice, Nude
- Neoplasm Transplantation
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Transplantation, Heterologous
- Tumor Cells, Cultured
- Tumor Protein, Translationally-Controlled 1
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Choi WJ, Park JG, Yoo SJ, Kim HO, Moon HR, Chun MW, Jung YH, Jeong LS. Syntheses of D- and L-cyclopentenone derivatives using ring-closing metathesis: versatile intermediates for the synthesis of D- and L-carbocyclic nucleosides. J Org Chem 2001; 66:6490-4. [PMID: 11559205 DOI: 10.1021/jo015733w] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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57 |
19
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Ogata K, Jeon S, Ko DS, Jung IS, Kim JH, Ito K, Kubo Y, Takei K, Saito S, Cho YH, Park H, Jang J, Kim HG, Kim JH, Kim YS, Choi W, Koh M, Uosaki K, Doo SG, Hwang Y, Han S. Evolving affinity between Coulombic reversibility and hysteretic phase transformations in nano-structured silicon-based lithium-ion batteries. Nat Commun 2018; 9:479. [PMID: 29396479 PMCID: PMC5797158 DOI: 10.1038/s41467-018-02824-w] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 01/02/2018] [Indexed: 11/09/2022] Open
Abstract
Nano-structured silicon is an attractive alternative anode material to conventional graphite in lithium-ion batteries. However, the anode designs with higher silicon concentrations remain to be commercialized despite recent remarkable progress. One of the most critical issues is the fundamental understanding of the lithium-silicon Coulombic efficiency. Particularly, this is the key to resolve subtle yet accumulatively significant alterations of Coulombic efficiency by various paths of lithium-silicon processes over cycles. Here, we provide quantitative and qualitative insight into how the irreversible behaviors are altered by the processes under amorphous volume changes and hysteretic amorphous-crystalline phase transformations. Repeated latter transformations over cycles, typically featured as a degradation factor, can govern the reversibility behaviors, improving the irreversibility and eventually minimizing cumulative irreversible lithium consumption. This is clearly different from repeated amorphous volume changes with different lithiation depths. The mechanism behind the correlations is elucidated by electrochemical and structural probing.
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research-article |
7 |
57 |
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Jung IY, Choi W, Kim J, Wang E, Park SW, Lee WJ, Choi JY, Kim HY, Uh Y, Kim YK. Nosocomial person-to-person transmission of severe fever with thrombocytopenia syndrome. Clin Microbiol Infect 2019; 25:633.e1-633.e4. [PMID: 30677496 DOI: 10.1016/j.cmi.2019.01.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/10/2019] [Accepted: 01/12/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES This study is an epidemiologic investigation of nosocomial severe fever with thrombocytopenia syndrome virus (SFTSV) transmission among healthcare workers (HCWs) after contact with an index patient. The aim of this study was to determine whether exposure to blood or bloody respiratory secretion is associated with human-to-human transmission of SFTSV. METHODS Eleven days after the index patient died, two HCWs who had close exposure to the patient presented with typical symptoms of SFTS. An epidemiological investigation was conducted on all 25 HCWs who had been in close contact with the index patient. Clinical and laboratory data were collected, and transmission rate before and after the index patient had haemorrhagic manifestations was analysed. RESULTS Among 25 HCWs who had direct contact with the index patient, five HCWs were confirmed to have SFTS. All five HCWs had contact to blood or bloody respiratory secretions of the index patient without adequate use of personal protective equipment (PPE). No HCW with contact before haemorrhagic manifestations of the index patient contracted SFTS. Overall, the transmission rate was higher for HCWs who had contact after the index patient had haemorrhagic manifestations (33.3%, five of 15 HCWs, vs. 0%, zero of ten HCWs, p 0.041). CONCLUSIONS In HCWs who are inadequately protected, person-to-person transmission of SFTSV may be associated with contact with blood or bloody respiratory secretions. Therefore, universal precaution and full PPE is highly recommended for protection against SFTSV when there are signs of bleeding.
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Kim W, Tang Y, Okada Y, Torrey TA, Chattopadhyay SK, Pfleiderer M, Falkner FG, Dorner F, Choi W, Hirokawa N, Morse HC. Binding of murine leukemia virus Gag polyproteins to KIF4, a microtubule-based motor protein. J Virol 1998; 72:6898-901. [PMID: 9658142 PMCID: PMC109902 DOI: 10.1128/jvi.72.8.6898-6901.1998] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A cDNA clone encoding a cellular protein that interacts with murine leukemia virus (MuLV) Gag proteins was isolated from a T-cell lymphoma library. The sequence of the clone is identical to the C terminus of a cellular protein, KIF4, a microtubule-associated motor protein that belongs to the kinesin superfamily. KIF4-MuLV Gag associations have been detected in vitro and in vivo in mammalian cells. We suggest that KIF4 could be involved in Gag polyprotein translocation from the cytoplasm to the cell membrane.
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Park B, Bang CH, Lee C, Han JH, Choi W, Kim J, Park GS, Rhie JW, Lee JH, Kim C. 3D wide-field multispectral photoacoustic imaging of human melanomas in vivo: a pilot study. J Eur Acad Dermatol Venereol 2020; 35:669-676. [PMID: 33037671 DOI: 10.1111/jdv.16985] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND The Breslow depth is an important parameter to determine the excision margin and prognosis of melanoma. However, it is difficult to accurately determine the actual Breslow depth before surgery using the existing ocular micrometer and biopsy technique. OBJECTIVES To evaluate the use of 3D wide-field multispectral photoacoustic imaging to non-invasively measure depth and outline the boundary of melanomas for optimal surgical margin selection. METHODS Six melanoma patients were examined in vivo using the 3D multispectral photoacoustic imaging system. For five cases of melanomas (one in situ, three nodular, and one acral lentiginous type melanoma), the spectrally unmixed photoacoustic depths were calculated and compared against histopathological depths. RESULTS Spectrally unmixed photoacoustic depths and histopathological depths match well within a mean absolute error of 0.36 mm. In particular, the measured minimum and maximum depths in the in situ and nodular type of melanoma were 0.6 and 9.1 mm, respectively. In the 3D photoacoustic image of one metastatic melanoma, feeding vessels were visualized in the melanoma, suggesting the neovascularization around the tumour. CONCLUSIONS The 3D multispectral photoacoustic imaging not only provides well-measured depth and sizes of various types of melanomas, it also visualizes the metastatic type of melanoma. Obtaining accurate depth and boundary information of melanoma before surgery would play a useful role in the complete excision of melanoma during surgery.
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Radák Z, Lee K, Choi W, Sunoo S, Kizaki T, Oh-ishi S, Suzuki K, Taniguchi N, Ohno H, Asano K. Oxidative stress induced by intermittent exposure at a simulated altitude of 4000 m decreases mitochondrial superoxide dismutase content in soleus muscle of rats. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1994; 69:392-5. [PMID: 7875134 DOI: 10.1007/bf00865401] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects were examined of 6-month intermittent hypobaric (4000 m) exposure on the antioxidant enzyme systems in soleus and tibialis muscles of rats. At the end of the 6-month experimental exposure, the six rats in both the exposed group and the control group were sacrificed. Immunoreactive mitochondrial superoxide dismutase (Mn-SOD) contents were measured as well as the activities of antioxidant enzymes [Mn-SOD, cytosolic SOD (Cu,Zn-SOD), catalase (CAT), and glutathione peroxidase (GPX)]. Thiobarbituric acid-reactive substances (TBARS) were also determined as an indicator of lipid peroxidation. The high altitude exposure resulted in a marked increase in TBARS content in soleus muscle, suggesting increased levels of oxygen free radicals. Conversely, significant decreases in both Mn-SOD content and activity in soleus muscle were noted after exposure. Such trends were not noticed in tibialis muscle. On the other hand, no significant changes in Cu,Zn-SOD, CAT, or GPX were observed in either muscle. These results suggested that the increases in lipid peroxidation were most probably a result of decreased Mn-SOD function which was more depressed in oxidative than in glycolytic muscle.
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Jinesh GG, Choi W, Shah JB, Lee EK, Willis DL, Kamat AM. Blebbishields, the emergency program for cancer stem cells: sphere formation and tumorigenesis after apoptosis. Cell Death Differ 2012; 20:382-95. [PMID: 23175184 DOI: 10.1038/cdd.2012.140] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Caspases mediate apoptosis and have also been implicated in stem-cell biology. How caspases are linked to stem-cell biology is not known. Here, we show that the apoptotic blebs of cancer cells fuse together to form novel structures called 'blebbishields'. Blebbishields form spheres by fusion. Both blebbishield formation and sphere formation involve active caspases and N-linked glycosylation. Sphere formation is enhanced by acidic pH and is counteracted by inhibitors of proton pump, caspases, and cholesterol. The blebbishields from VEGFR2(High) cells are capable of enhanced sphere formation. Blebbishields express transiently downregulated stem-cell markers and the sphere-forming blebbishield-derived cells are tumorigenic. Our study demonstrates that the cancer stem cells can survive after apoptosis by blebbishield formation and subsequent sphere formation.
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Research Support, Non-U.S. Gov't |
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Hubschman JP, Bourges JL, Choi W, Mozayan A, Tsirbas A, Kim CJ, Schwartz SD. 'The Microhand': a new concept of micro-forceps for ocular robotic surgery. Eye (Lond) 2009; 24:364-7. [PMID: 19300461 DOI: 10.1038/eye.2009.47] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To test the feasibility of retinal manipulations using a new micromanipulator (Microhand) for ocular robotic microsurgery. METHODS Pneumatically actuated four-finger microhands were developed at UCLA with micro electromechanical systems (MEMS) technology to mimic a human hand for small object manipulation. Microhands with four 4 mm finger lengths were used for this study to lift caliper weights and fresh retinal tissue of porcine cadaver eyes to find the maximum force at a given pressure and feasibility of the microhands for retinal manipulation in real surgery. RESULTS A full closure of the microhand used for caliper weight lifting was achieved under 65 psi (448 kPa) of air pressure. The four-fingered microhand was able to develop about 20 mN of total lifting force and 5 mN per finger at 80 psi (551 kPa), and was strong enough to displace and lift the retina of pig eyes. CONCLUSIONS The microhand is able to apply calibrated forces to ocular tissues and is suitable for ocular microsurgical procedures. This new tool would be useful in the development of robotic microsurgery.
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