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ABSTRACT: Many human immunodeficiency virus 1 (HIV-1) researchers focus on the developing new anti-reservoir therapy to eradicate HIV-1 provirus from the HIV-1-infected patients. HIV-1 provirus is the major obstacle for effective HIV-1 treatment because it integrates into the host genome and can produce a virus progeny after stopping highly active antiretroviral therapy (HAART). We established two novel cell lines latently infected with HIV-1 by limiting dilution cloning of A3.01 cells infected with HIV-1. Analysis of the flanking sequence of HIV-1 proviral DNA integrated into chromosomal cellular DNA revealed that proviral DNA was inserted into different sites of different chromosomes in the two examined cell lines. In these lines, virus reactivation could be induced by a phorbol 12-myristate 13-acetate (PMA) treatment that resulted in a marked increase of the production HIV-1 p24 antigen and appearance of the infectious virus. The novel cell lines latently infected with HIV-1 represent further tool for the study of molecular mechanisms of viral latency and development of anti-reservoir therapy of HIV-1 infection.
Acta virologica 01/2011; 55(2):155-9. · 0.68 Impact Factor
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ABSTRACT: Histone deacetylase plays an important role in HIV latency. Novel histone deacetylase inhibitors, CG05 and CG06, were evaluated for their roles in HIV latency using ACH2 cells. Both inhibitors were highly efficient in reactivation of provirus and exerted lesser toxicity compared with other known histone deacetylase inhibitors. Histone acetylation increased when proviruses were reactivated by the compounds. These new inhibitors may contribute to the reduction of the HIV reservoir when used in conjunction with highly active antiretroviral therapy.
AIDS (London, England) 02/2010; 24(4):609-11. · 4.91 Impact Factor
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ABSTRACT: HIV-1 specific cytotoxic T lymphocytes (CTLs) have an important role as antiviral effector cells for controlling HIV-1 infection.
To investigate CTL response during the early stage of HIV infection, we measured immunity-related factors including CD4+ T cell counts, CD8+ T cell counts, HIV-1 RNA viral loads and IFN-γ secretion according to CTL response in 78 selected primary HIV-1-infected Koreans.
The CTL response was strongly induced by HIV-1 specific Gag and Nef peptides (p = 0.016) compared with induction by Tat or Env peptides. These results suggest that the major antiviral factors inducing strong HIV-specific CTL responses are associated with the Gag and Nef viral regions in primary HIV-1 infected Koreans. The relationship between viral load and CTL response showed varying correlations with time following HIV infection. CTL response was inversely correlated with viral loads at preseroconversion stage I (r = -0.224 to -0.33) and changed to a positive correlation at the preseroconversion stage II (r = 0.132 to 0.854). Finally, it changed to an inverse correlation again after seroconversion until a viral set point was established on serological profiling (r = -0.195 to -0.407).
These findings demonstrate a dynamic correlation between viral load and subsequent CTL responses during early HIV infection.
Virology Journal 01/2010; 7:239. · 2.34 Impact Factor
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ABSTRACT: In this paper, a tetrahedral interpolation technique is utilized to build new type architecture for real time color gamut mapping which has been known to be one of promising methods to enhance display quality of digital and/or high-definition TV. It is common practice to simplify the required complex computations for the mapping by adopting three-dimensional interpolation techniques. If carefully arranged, the tetrahedral interpolation can be computed with simpler operations compared to the other types of interpolation such as a cubic or three-bilinear interpolation in the conventional reduced resolution look-up table. With these simplified operations, the proposed method reduces the required computational cost and the complexity of hardware implementation. The proposed method is implemented in VHDL code and the simulation results show that the proposed method reduces the number of gates needed to hardware implementation without loss of color reproduction quality.
IEEE Transactions on Consumer Electronics 06/2009; · 0.94 Impact Factor
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ABSTRACT: Resistance to metronidazole (MTZ) in Helicobacter pylori is associated with mutations in rdxA, encoding an oxygen-insensitive NADPH nitroreductase, and mutations in frxA, encoding a NAD(P)H-flavin oxidoreductase. Despite this association, the strict correlation of MTZ resistance with mutations in rdxA or frxA is still controversial. In this study, rdxA allelic replacement was used to distinguish resistance-associated nucleotide mutations from the natural genetic diversity of H. pylori. Replacement with truncated rdxA resulted in MTZ resistance, whereas replacement with missense-mutated rdxA from resistant clinical isolates failed to yield MTZ resistance. Thus, although truncation of rdxA confers MTZ resistance in G27 H. pylori, MTZ resistance found in other clinical isolates is not due to the identified amino-acid substitutions. Three of our MTZ-resistant clinical isolates expressed functional rdxA and two of these also encoded full-length frxA. Therefore, MTZ resistance can arise in H. pylori possessing functional rdxA, suggesting that other factors are involved in MTZ resistance.
The Journal of Antibiotics 02/2009; 62(1):43-50. · 1.65 Impact Factor
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ABSTRACT: Helicobacter pylori causes diseases ranging from gastritis to peptic ulcer disease to gastric cancer. Geographically, areas with high incidences of H. pylori infection often overlap with areas with high incidences of gastric cancer, which remains one of the leading causes of cancer-related deaths worldwide. Strains of H. pylori that carry the virulence factor cytotoxin-associated gene A (cagA) are much more likely to be associated with the development of gastric cancer. Moreover, particular C-terminal polymorphisms in CagA vary by geography and have been suggested to influence disease development. We conducted a large-scale molecular epidemiologic analysis of South Korean strains and herein report a statistical link between the East Asian CagA EPIYA-ABD genotype and the development of gastric cancer. Characterization of a subset of the Korean isolates showed that all strains from cancer patients expressed and delivered phosphorylatable CagA to host cells, whereas the presence of the cagA gene did not strictly correlate to expression and delivery of CagA in all noncancer strains.
Journal of clinical microbiology 02/2009; 47(4):959-68. · 4.16 Impact Factor
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IEICE Transactions. 01/2009; 92-D:97-101.
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ABSTRACT: Ambient measurements were made using two sets of annular denuder system during the four seasons (April 2001 to February 2002) and were then compared with the results during the period of 1996-1997 to estimate the trends and seasonal variations in concentrations of gaseous and fine particulate matter (PM2.5) principal species. Annual averages of gaseous HNO3 and NH3 increased by 11% and 6%, respectively, compared with those of the previous study, whereas HONO and SO2 decreased by 11% and 136%, respectively. The PM2.5 concentration decreased by -17%, 35% for SO4(2-), and 29% for NH4+, whereas NO3- increased by 21%. Organic carbon (OC) and elemental carbon (EC) were 12.8 and 5.98 microg/m(-3), accounting for -26 and 12% of PM2.5 concentration, respectively. The species studied accounted for 84% of PM2.5 concentration, ranging from 76% in winter to 97% in summer. Potential source contribution function (PSCF) analysis was used to identify possible source areas affecting air pollution levels at a receptor site in Seoul. High possible source areas in concentrations of PM2.5, NO3-, SO4(2-), NH4+, and K+ were coastal cities of Liaoning province (possibly emissions from oil-fired boilers on ocean liners and fishing vessels and industrial emissions), inland areas of Heibei/Shandong provinces (the highest density areas of agricultural production and population) in China, and typical port cities (Mokpo, Yeosu, and Busan) of South Korea. In the PSCF map for OC, high possible source areas were also coastal cities of Liaoning province and inland areas of Heibei/Shandong provinces in China. In contrast, high possible source areas of EC were highlighted in the south of the Yellow Sea, indicating possible emissions from oil-fired boilers on large ships between South Korea and Southeast Asia. In summary, the PSCF results may suggest that air pollution levels in Seoul are affected considerably by long-range transport from external areas, such as the coastal zone in China and other cities in South Korea, as well as Seoul itself.
Journal of the Air & Waste Management Association (1995) 08/2006; 56(7):911-21. · 1.52 Impact Factor
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ABSTRACT: A color gamut mapping is a process of mapping colors from the gamut of a source medium to fit the gamut of the reproduction medium. The input and output relationship of the color gamut mapping is highly nonlinear and there is a need to process the color gamut mapping in real-time. In this paper, a neural network is applied to the real time color gamut mapping. By the learning ability, the neural network is trained to effectively handle the high nonlinearity of the color gamut mapping. And also real time hardware architecture of neural network is presented in this paper. Simulation result shows the soundness of the proposed method.
Soft Computing in Industrial Applications, 2005. SMCia/05. Proceedings of the 2005 IEEE Mid-Summer Workshop on; 07/2005
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Advances in Natural Computation, First International Conference, ICNC 2005, Changsha, China, August 27-29, 2005, Proceedings, Part II; 01/2005
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ABSTRACT: Fine particles (PM2.5) were collected during all four seasons, from April 2001 to February 2002, in Seoul, South Korea, using an annular denuder system. Elemental compositions of ambient PM2.5 were analyzed using the proton-induced X-ray emission method. The greatest contributors (> or = 2%) to the PM2.5 mass were sulfur (S), silicon (Si), chlorine (Cl), aluminum (Al), and iron (Fe) in the spring; S in the summer; and S and Cl in the fall. S, Cl, and Si were the major elements in the winter. S was the most abundant species among the elements, ranging from 5.3 to 7.9%, followed by Si and Cl. From analysis of variance, PM2.5 mass, Al, Si, potassium, calcium, and Fe showed significant seasonal differences during the four seasons (p < 0.001). Enrichment factor (EF) analysis was carried out to identify the sources affecting the aerosol in the Seoul area. On the basis of the mean EF values, elemental S, copper, zinc, and lead may be emitted from anthropogenic sources (EF > 50). Elemental Al, Si, titanium, and Fe may be emitted from crustal sources (EF < 3). Additionally, a correlation analysis was carried out for source identification. The results of the correlation analysis were confirmed by the results of the EF analysis.
Journal of the Air & Waste Management Association (1995) 05/2004; 54(4):432-9. · 1.52 Impact Factor
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Sang Woo Kim, Hak Sung Lee,
Seung Kew Yoon,
Woo Chul Chung,
Young Seok Cho,
Jeong Jo Jeong,
In Seok Lee,
Kang Moon Lee,
Dong Soo Lee,
Myung-Gyu Choi,
In-Sik Chung,
Doo Ho Park
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ABSTRACT: The expression of CD40 in gastric cancer has not been studied. The aims of this study were to determine the expression of CD40 in gastric cancer and to investigate the effect of CD40 on the apoptosis of gastric cancer cells.
We examined the expression of CD40 by immunohistochemistry and flow cytometry. CD40 mRNA in 5 gastric cancer cell lines was analyzed by RT-PCR. To assess the effect of CD40 on the viability of gastric cancer cells, we performed MTT assay. The effect of CD40 signaling on the apoptosis of gastric cancer cells was examined by annexin V affinity assay.
Twelve of twenty human gastric cancer tissues demonstrated positive staining for CD40. Among 5 gastric cancer cell lines, AGS cell line expressed membrane-bound CD40 antigen and CD40 mRNA. In AGS cells, CD40 stimulation significantly reduced the cell viability. CD40 ligation significantly increased the apoptosis in AGS cells compared to the control.
CD40 is expressed in human gastric cancer tissues and gastric cancer cell line, and induces apoptosis in gastric cancer cells. These results suggest that CD40 expression in gastric cancer may play an important role in host defense mechanism against the gastric cancer.
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 11/2003; 42(4):274-82.
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ABSTRACT: In vitro subcultures of bacteria can lead to genetic and phenotypic changes. This study aimed at investigating the effect of repeated subcultures on the adhesion, motility, cytotoxicity, and gastric inflammation caused by Helicobacter pylori. H.pylori SS1 strain was subcultured 64 times on agar plates containing Brucella broth and 5% bovine calf serum. The adhesion, motility, cytotoxicity, and gastric inflammation produced in Mongolian gerbils were compared between the first and 64th subcultured strain. The adhesion rates, following 3 hr exposure of AGS cells to either the first strain or the 64th-transferred strain, were 21% and 12%, respectively. The motility of the 64th-transferred strain decreased significantly when compared to the 1st strain (9.1 mm vs. 15.1 mm). The cytotoxicity index tended to be higher in the first strain than in the 64th-transferred strain (73.7% vs. 69.2%). The initial infection rate on the gerbils showed no difference between the two strains. However, chronic gastric inflammation of the first strain-infected gerbils was somewhat more severe than that of the 64th-transferred strain-infected gerbils. Therefore, the use of repeatedly subcultured strains of H. pylori in virulence experiments can lead to different results from those of the original strain.
Journal of Korean Medical Science 07/2002; 17(3):302-6. · 0.99 Impact Factor
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ABSTRACT: Background. It is still a point of controversy whether Helicobacter pylori-infected patients are more likely to develop mucosal damage while taking NSADIs. Selective cyclooxygenase (COX-2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori-induced gastritis. The aim of this study was to evaluate the effects of selective COX-2 and nonselective NSAIDs on H. pylori-induced gastritis.Methods. After intragastric administration of indomethacin, NS-398 or vehicle alone, once daily for 5 days in H. pylori-infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E2 (PGE2) concentration. We investigated whether H. pylori infection induced the COX-2 expression.Results. In H. pylori-uninfected groups, the indomethacin-treated group showed the highest mucosal damage score and the lowest PGE2 concentration. There was no difference in mucosal damage scores and PGE2 concentration between NS-398 and vehicle-alone treated group. In H. pylori-infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin-treated group showed the lowest PGE2 concentration, similar to that of the NS-398 and vehicle-alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori-infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori-infected or uninfected groups. COX-2 protein expression was observed in H. pylori-infected Mongolian gerbils but not in uninfected ones.Conclusions. Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSIADs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.
Helicobacter 03/2002; 7(1):14 - 21. · 3.15 Impact Factor
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ABSTRACT: It is still a point of controversy whether Helicobacter pylori-infected patients are more likely to develop mucosal damage while taking NSAIDs. Selective cyclooxygenase (COX-2) inhibitors may be associated with less severe gastric mucosal damage than conventional NSAIDs, but this association is undefined in H. pylori-induced gastritis. The aim of this study was to evaluate the effects of selective COX-2 and nonselective NSAIDs on H. pylori-induced gastritis.
After intragastric administration of indomethacin, NS-398 or vehicle alone, once daily for 5 days in H. pylori-infected and uninfected Mongolian gerbils, we evaluated gastric mucosal damage, inflammatory cell infiltration and prostaglandin E2 (PGE2) concentration. We investigated whether H. pylori infection induced the COX-2 expression.
In H. pylori-uninfected groups, the indomethacin-treated group showed the highest mucosal damage score and the lowest PGE2 concentration. There was no difference in mucosal damage scores and PGE2 concentration between NS-398 and vehicle-alone treated group. In H. pylori-infected groups, there was no difference in mucosal damage scores, irrespective of the type of drugs administered. The indomethacin-treated group showed the lowest PGE2 concentration, similar to that of the NS-398 and vehicle-alone treated groups, both without H. pylori infection. Gastric neutrophil and monocyte infiltration scores were higher in H. pylori-infected groups than in uninfected groups. However, there was no difference in these scores according to the type of drugs administered, within H. pylori-infected or uninfected groups. COX-2 protein expression was observed in H. pylori-infected Mongolian gerbils but not in uninfected ones.
Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSAIDs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.
Helicobacter 03/2002; 7(1):14-21. · 3.15 Impact Factor
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ABSTRACT: Fine particles were collected over four seasons from October 1995 to August 1996 to evaluate the chemical characteristics of principal PM2.5 components in Chongju, South Korea. The annual mean concentrations of PM2.5 (dp⩽2.5 μm), sulfate, nitrate, ammonium, elemental carbon (EC) and organic carbon (OC) were 44.2, 8.22, 3.63, 2.84, 4.44 and 4.99 μg m−3, respectively. The sum of the species measured from this study accounted for 50–62% of the PM2.5 mass. Sulfate was the most abundant species and constituted 13–23% of the PM2.5 mass. The EC and OC accounted for 17–28% of PM2.5. The correlation between OC and EC was strong, and the annual mean ratio of OC/EC was 1.12, suggesting that OC measured in the Chongju area may be emitted directly in particulate form as a primary aerosol.
Atmospheric Environment.
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ABSTRACT: The annular denuder system (ADS) was used to determine quantitatively the relationship between indoor and outdoor air. All indoor and outdoor measurements were done simultaneously using the ADS in Chongju, Korea during the summer season. The data set was collected on eight different days with a 24 h sampling period from 27 July 1995 to 27 August 1995. The chemical species measured were HNO3, HNO2, SO2 and NH3 in the gas phase and PM2.5(dp < 2.5 μm), SO2−4 N0−3 and NH+4 in the particulate phase. For these data, outdoor air contributed from 50 to 100% of indoor pollution environment during the summer season in Korea. Indoor concentrations for HN03, SO2, PM2.5, S02−4 and NH+4 were significantly related to the corresponding outdoor concentrations. These data are the first reported in Korea collected with the ADS.
Atmospheric Environment.
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ABSTRACT: Very high PM2.5 concentrations have been observed, which were classified as hazy episodes, on several days in the fall of 2001 in the Seoul metropolitan area. It was the worst air pollution event ever seen in this area. In order to develop the scientific PM2.5 control strategies for hazy episodes in this area, it is necessary to investigate the chemical characteristics of air pollutants during hazy episodes and evaluate where these high concentrations came from. All measurements were simultaneously taken using two sets of annular denuder system (ADS) to collect acidic gas pollutants and PM2.5 species. To characterize chemical species for the hazy days, the data were divided into the hazy and non-hazy episodes. Atmospheric HNO3, HNO2, and SO2 during the hazy episodes increased by a factor of about 1.6–2.1 compared to those during the non-hazy episodes. The NO3−, SO42−, and NH4+ during the hazy episodes increased by a factor of about 4.4–6.1 compared to those during the non-hazy episodes. In addition, ambient PM2.5 concentrations for hazy days were a factor of 1.3–3.3 in excess of the 65 μg m−3, which is the 24-h US PM2.5 NAAQS. The mean concentrations of carbonaceous species during the hazy and non-hazy episodes were 29.26 and 11.76 μg m−3 for organic carbon (OC) and were 9.75 and 7.23 μg m−3 for elemental carbon (EC), respectively. Higher OC concentrations were observed in the hazy episodes, which may be influenced by biomass burning which occurred from the outside of the Seoul area rather than the local atmospheric formation of secondary OC. The results of the backward air trajectory analysis and weather charts reconfirmed the possibility of the effect of biomass burning. The highest contributors to the PM2.5 mass during the hazy event were major ionic species such as: NO3−, SO42−, and NH4+.
Atmospheric Environment.
