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Koo H, Schobel B, Scott-Anne K, Watson G, Bowen WH, Cury JA, Rosalen PL, Park YK. Apigenin and tt-farnesol with fluoride effects on S. mutans biofilms and dental caries. J Dent Res 2005; 84:1016-20. [PMID: 16246933 PMCID: PMC1490022 DOI: 10.1177/154405910508401109] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Apigenin (Api) and tt-farnesol (Far) are two naturally occurring agents that affect the development of cariogenic biofilms. Fluoride (F) interferes physicochemically with caries development and also exhibits antibacterial activity. We examined whether the association of Api and Far enhance the anti-caries properties of F by acting cooperatively on the expression of virulence of Streptococcus mutans. The biological effects of each of the agents were greatly enhanced when used in combination with F. In general, biofilms treated with Api and/or Far in combination with F displayed less biomass and fewer insoluble glucans and iodophilic polysaccharides than did those treated with the test agents alone (P < 0.05). The combination of the test agents with F was highly effective in preventing caries development in rats, especially Api+Far+F, and results were comparable with those observed with chlorhexidine + F (positive control). Results from these studies showed that apigenin and tt-farnesol may enhance the cariostatic effectiveness of fluoride.
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Jeon K, Koh WJ, Kwon OJ, Suh GY, Chung MP, Kim H, Lee NY, Park YK, Bai GH. Recovery rate of NTM from AFB smear-positive sputum specimens at a medical centre in South Korea. Int J Tuberc Lung Dis 2005; 9:1046-51. [PMID: 16158899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
OBJECTIVE To investigate the recovery rate of non-tuberculous mycobacteria (NTM) from acid-fast bacilli (AFB) smear-positive sputum specimens at a tertiary care medical centre in South Korea with a high pulmonary tuberculosis (PTB) burden. DESIGN Retrospective analysis of data from AFB smear- and culture-positive sputum specimens collected between January 1998 and December 2001. RESULTS Over 4 years, 1328 sputum specimens collected from 616 patients were AFB smear- and culture-positive. NTM were recovered from 9.1% (121/1328) of the smear-positive sputum specimens, and from 8.1% (50/616) of patients with smear-positive sputum. NTM were isolated at least twice in 94% (47/50) of the patients from whom NTM was recovered. The most common organism found was Mycobacterium avium complex, followed by M. abscessus. CONCLUSION These results suggest that a substantial proportion of patients at a tertiary care medical centre in South Korea with AFB smear-positive sputum specimens may have NTM lung disease rather than PTB.
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Koh WJ, Kwon OJ, Park YK, Lew WJ, Bai GH. Development of multidrug resistance during treatment of isoniazid-resistant tuberculosis. Eur Respir J 2005; 26:557. [PMID: 16135740 DOI: 10.1183/09031936.05.00045605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kim K, Lee YH, Kwon H, Kim JM, Kim IS, Park YK. Averaging algorithm based on data statistics in magnetocardiography. NEUROLOGY & CLINICAL NEUROPHYSIOLOGY : NCN 2004; 2004:42. [PMID: 16015714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
An algorithm for automatic averaging of a magnetocardiogram (MCG) is described. Due to the relatively low signal-to-noise ratio in the MCG, the measured MCG data are often averaged to be analyzed. Generally, R-peaks are used as trigger points, which become anchors for superposition and we can obtain an averaged epoch eventually. However, we have to determine several parameters, such as the threshold magnitude for recognizing R-peak, the time-period of the epoch window, and which channel has dominant R-peaks. In order to determine these parameters automatically, we utilize the magnitude histogram of the root-mean-square waveform of all the channels. We can determine the threshold magnitudes for recognizing R-peaks and T-peaks, respectively, by using the characteristic distribution of the MCG signal histogram. Peak detection procedure using these thresholds records all the locations of the R-peaks and T-peaks, thus we get the average latencies of the R-T intervals and the R-R intervals. From these latencies, we estimate the full width of the epoch window. By adding a routine for processing double R-peaks, our algorithm could conduct the MCG averaging sequence fully automatically. The algorithm has been tested on recordings of 40 normal subjects and 15 patients suffering from myocardial ischemia, and we conclude that this algorithm reliably performs the averaging sequence. The MCG recordings are measured by our 62-channel planar gradiometer system in a magnetically shielded room.
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Kim K, Lee YH, Kwon H, Kim JM, Kim IS, Park YK. Optimal sensor distribution for measuring the tangential field components in MCG. NEUROLOGY & CLINICAL NEUROPHYSIOLOGY : NCN 2004; 2004:60. [PMID: 16012625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We discuss the optimal arrangement of detectors for a 52-channel magnetocardiogram (MCG) system measuring tangential components of the cardiac magnetic fields. Nowadays, most MCG instruments are designed to cover the whole heart area to maximize the information available from the myocardial magnetic field in a simultaneous measurement. In such a system, detectors should be spread over a sufficiently wide area. However, an increased diameter of the cooling dewar will result in more heat-loss and higher production and maintenance costs. Therefore, we reviewed the spatial sampling theory to determine the proper interval between detectors, and we decided on the number of channels to cover the whole heart area. In order to fit the detector array on the cylindrical dewar economically, we removed the detectors at the corners of the square array. Through simulations using the confidence region method, we verified that our design of the detector array is enough to obtain adequate information from the heart. Simulations also suggested that tangential-component MCG measurement can localize deep current dipoles better than normal-component measurement with the same confidence volume; therefore, we conclude that measurement of the tangential component is more suitable to an MCG system than the normal component.
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Kwon H, Kim JM, Lee YH, Kim K, Park YK, Nam K, Kuriki S. Auditory evoked field responses in the left hemisphere to morphosyntactic violations in Korean sentence. NEUROLOGY & CLINICAL NEUROPHYSIOLOGY : NCN 2004; 2004:29. [PMID: 16012691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To investigate multiple cortical regions associated with syntactic processes at the sentence level, auditory evoked field responses to morphosyntactic violations were measured over the left hemisphere of seven subjects. Subjects were asked to judge the acceptability of the final verb in verb-ending Korean sentence. Measured field data were transformed to the fields that would be detected on a standard sensing plane and averaged across subjects in different violation conditions. In the grand average data, we found distinct features at latencies of 400 ms and 600 ms, which seem to be specific to morphosyntactic processes. Equivalent current dipoles (ECDs) plotted on a standard brain indicate the inferior frontal region and the superior temporal gyrus for 400 ms component, and the middle temporal gyrus for 600 ms component. Our MEG study localized the distinct cortical regions involved in syntactic processes, which may be reflected in LAN and P600 of ERP.
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Lee JW, Lee HW, Kim SW, Lee SY, Park YK, Han JH, Choi SI, Yi YS, Yun Z. Nitrogen removal characteristics analyzed with gas and microbial community in thermophilic aerobic digestion for piggery waste treatment. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2004; 49:349-357. [PMID: 15137444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In order to characterize the nitrogen conversion characteristics in a thermophilic aerobic digestion (TAD) system, a laboratory study has been conducted with the analysis of effluent gas and microbial community in the sludge samples. The lab TAD system was operated with HRT of 3 days and 60 degrees C. Based on the nitrogen mass balance, it has been found that about 2/3 of the daily load of nitrogen was converted to the gaseous form of nitrogen whereas cellular transformation and unmetabolized nitrogen accounted for about 1/3. Among the gaseous nitrogen transformation, significant amount of influent nitrogen had been converted to N2 gas (29% of influent N) and N2O (9% of influent N). Ammonia conversion was only 28% of influent N. The detection of N2O gas is a clear indication of the biological nitrogen reduction process in the thermophilic aerobic digester. No conclusive evidence for the existence of aerobic deammonification has been found. The microbial community analysis showed that thermophilic bacteria such as Bacillus thermocloacae, Bacillus sp. and Clostridial groups dominated in this TAD reactor. The diverse microbial community in TAD sludge may play an important role in removing both strong organics and nitrogen from piggery waste.
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83
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Koo H, Hayacibara MF, Schobel BD, Cury JA, Rosalen PL, Park YK, Vacca-Smith AM, Bowen WH. Inhibition of Streptococcus mutans biofilm accumulation and polysaccharide production by apigenin and tt-farnesol. J Antimicrob Chemother 2003; 52:782-9. [PMID: 14563892 DOI: 10.1093/jac/dkg449] [Citation(s) in RCA: 265] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES Apigenin is a potent inhibitor of glucosyltransferases and tt-farnesol affects the membrane integrity of Streptococcus mutans. We investigated the influence of apigenin and tt-farnesol, alone and in combination, on the accumulation, polysaccharide composition and viability of S. mutans UA159 biofilms. METHODS Initially, biofilms were grown for 54 h; then, the early-formed biofilms were treated for 1 min twice daily with one of the following: (i). 1.33 mM tt-farnesol; (ii). 1.33 mM apigenin; (iii). apigenin + tt-farnesol (1.33 mM each); (iv). vehicle control (20% ethanol with 0.75% dimethyl sulphoxide); (v). 0.12% chlorhexidine (1.33 mM); or (vi). physiological saline (145 mM NaCl). The procedure was repeated at biofilm ages of 78 and 102 h, and biofilms were harvested at 126 h. The dry weight, protein concentration, number of cfu, and polysaccharide composition per biofilm were determined. RESULTS The dry weights of the biofilms treated with the test agents were significantly less (30-50%) than those treated with vehicle control (P < 0.05). Biofilms treated with the test agents also resulted in lower amounts of extracellular alkali-soluble glucans, intracellular iodophilic polysaccharides and, to a lesser extent, fructans. The fructosyltransferase activity was affected only by apigenin and apigenin + tt-farnesol. The recoverable viable counts of S. mutans were slightly lower (0.5 to 1 log10 decrease in cfu/biofilm) after apigenin and tt-farnesol treatments compared with the vehicle control. Chlorhexidine displayed potent bactericidal activity, and virtually halted the further accumulation of early-formed (54 h old) biofilms. CONCLUSIONS Apigenin and tt-farnesol affected the accumulation and polysaccharide content of S. mutans biofilms without major impact on the bacterial viability.
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Lee HW, Lee SY, Lee JO, Kim HG, Park JB, Choi E, Park YK. The microbial community analysis of a 5-stage BNR process with step feed system. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2003; 48:135-141. [PMID: 14682580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The microbial communities of 5-stage BNR activated sludge samples were analyzed using fluorescence in-situ hybridization (FISH) and 16S rDNA characterization. The total cell numbers of each reactor were from 2.36 x 10(9) cells/ml to 2.83 x 10(9) cells/ml. From 56.5% to 62.0% of total DAPI cell counts were hybridized to the most bacterial specific probe EUB 338. Among them, beta-proteobacteria were most dominant in each tank. The number of phosphate accumulating organisms (PAOs) was almost 50% of the total cell number in anoxic-1 tank, and these results indicate that this process has a high content of denitrifying phosphorus accumulating organisms (dPAOs). In contrast with FISH, 16S rDNA analysis showed that dominant groups were the Cytophaga-Flavobacterium group and high G+C% gram-positive bacteria, which were determined as PAOs in anoxic-1 tank. The beta subclass Proteobacteria did not accumulate a large amount of polyphosphate. The overall results indicate that high G+C% gram-positive bacteria and the Cytophaga-Flavobacterium group might play a key role as dPAOs in this process.
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Kwon H, Lee YH, Kim JM, Park YK, Kuriki S. Localization accuracy of single current dipoles from tangential components of auditory evoked fields. Phys Med Biol 2002; 47:4145-54. [PMID: 12502039 DOI: 10.1088/0031-9155/47/23/302] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We investigated the localization accuracy of single current dipoles from the tangential components of auditory evoked fields. The tangential fields were measured using planar gradiometers arranged in a way so as to detect two orthogonal field components parallel to a flat plane. Field responses to 1 kHz pure tones were recorded and equivalent current dipoles (ECDs) of N1m peak were estimated based on a locally fitted spherical conductor model. As a measure of localization accuracy, the standard deviation of the coordinates of the ECDs of N1m was obtained from repeated measurements for one subject. The estimated ECDs had a standard deviation of 5.5 mm and their mean location was at the supratemporal plane in the sylvian fissure on the MR image of the subject. In order to investigate the contribution of various errors to the localization accuracy, simulations using a sphere model and experiments using a realistically shaped skull phantom were performed. It was found that the background noise, which consisted of instrumental noise and spontaneous brain fields, was the main source of the errors that could explain the observed standard deviation. Further, the amount of systematic error was much less than the standard deviation due to the background noise. These results suggest that the volume currents in a non-spherical conductor shape such as the temporal region do not produce substantial errors in the localization of current dipoles from tangential components of auditory evoked fields.
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86
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Koo H, Pearson SK, Scott-Anne K, Abranches J, Cury JA, Rosalen PL, Park YK, Marquis RE, Bowen WH. Effects of apigenin and tt-farnesol on glucosyltransferase activity, biofilm viability and caries development in rats. ORAL MICROBIOLOGY AND IMMUNOLOGY 2002; 17:337-43. [PMID: 12485324 DOI: 10.1034/j.1399-302x.2002.170602.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Propolis, a resinous hive product secreted by Apis mellifera bees, has been shown to reduce the incidence of dental caries in rats. Several compounds, mainly polyphenolics, have been identified in propolis. Apigenin and tt-farnesol demonstrated biological activity against mutans streptococci. We determined here their effects, alone or in combination, on glucosyltransferase activity, biofilm viability, and development of caries in rats. Sprague-Dawley rats were infected with Streptococcus sobrinus 6715 and treated topically twice daily as follows: (1) tt-farnesol, (2) apigenin, (3) vehicle control, (4) fluoride, (5) apigenin +tt-farnesol, and (6) chlorhexidine. Apigenin (1.33 mM) inhibited the activity of glucosyltransferases in solution (90-95%) and on the surface of saliva-coated hydroxyapatite beads (35-58%); it was devoid of antibacterial activity. tt-Farnesol (1.33 mM) showed modest antibacterial activity against biofilms and its effects on glucosyltransferases were minimal. The incidence of smooth-surface caries was significantly reduced by apigenin +tt-farnesol (60%), fluoride (70%), and chlorhexidine (72%) treatments compared to control (P < 0.05).
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87
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Chai JY, Han ET, Park YK, Guk SM, Park JH, Lee SH. Stictodora lari (Digenea: Heterophyidae): the discovery of the first human infections. J Parasitol 2002; 88:627-9. [PMID: 12099440 DOI: 10.1645/0022-3395(2002)088[0627:sldhtd]2.0.co;2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Stictodora lari Yamaguti, 1939 (Digenea: Heterophyidae) was originally reported as an avian intestinal parasite and is here reported in humans. The patients were adults, aged 46-69 (2 men and 4 women), who resided in coastal villages in Sachon-gun, Kyongsangnam-do, or Shinan-gun, Chollanam-do. in the Republic of Korea. The worms were recovered after praziquantel treatment and purgation with magnesium salts. A total of 15 S. lari specimens (1-10 per individual) was collected, together with 5 other species of intestinal flukes. The flukes were morphologically characterized by a small body size (0.70-0.86 mm long and 0.27-0.36 mm wide), a ventrogenital sac, and a gonotyl armed with 70-80 spines in the form of a comma or reversed comma lying along their lateral margin. The patients had eaten the raw flesh of mullets and gobies that had been caught in an estuary near their villages. To the best of our knowledge, this is the first record of a human S. lari infection.
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Chung PR, Jung Y, Park YK, Hwang MG. Host specificity of Austropeplea ollula (Gastropoda: Lymnaeidae) to miracidial infection with a human intestinal fluke Neodiplostomum seoulense (Trematoda: Diplostomatidae) in Korea. J Parasitol 2002; 88:630-1. [PMID: 12099442 DOI: 10.1645/0022-3395(2002)088[0630:hsoaog]2.0.co;2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Three species of freshwater pulmonate snails of Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula, and Fossaria truncatula. Of these 3 species, only A. ollula was naturally infected with Neodiplostomum seoulense cercariae (prevalence, 0.3%). In experiments with the laboratory-reared snails, A. ollula was found to be susceptible to the N. seoulense miracidia (prevalence, 10%). This is the first report of A. ollula as the first molluscan intermediate host for N. seoulense in Korea.
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Park YK, Kim BJ, Ryu S, Kook YH, Choe YK, Bai GH, Kim SJ. Cross-resistance between rifampicin and KRM-1648 is associated with specific rpoB alleles in Mycobacterium tuberculosis. Int J Tuberc Lung Dis 2002; 6:166-70. [PMID: 11931418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
KRM-1648 resistant Mycobacterium tuberculosis strains were identified from a collection of rifampicin-resistant strains. Several strains had novel rpoB gene mutations in codons 512, 529 and 533 of the rpoB gene. The strains with mutations in codons 526 or 531, major mutation sites in rifampicin-resistant M. tuberculosis, were resistant to KRM-1648. Also, the strains with other mutations in the rpoB gene that were initially susceptible to KRM-1648 were prone to developing KRM-1648 resistance after further mutation. Thus, KRM-1648 is unlikely to be useful for the treatment of rifampicin-resistant tuberculosis.
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Chung PR, Jung Y, Park YK, Hwang MG, Soh CT. Corbicula fluminea (Bivalvia: Corbiculidae): a possible second molluscan intermediate host of Echinostoma cinetorchis (Trematoda: Echinostomatidae) in Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2001; 39:329-32. [PMID: 11775336 PMCID: PMC2728211 DOI: 10.3347/kjp.2001.39.4.329] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
More than 1,500 clams of Corbicula fluminea, the most favorable food source of freshwater bivalves in Korea, were collected from 5 localities to examine cercarial and metacercarial infection with Echinostoma cinetorchis. Although 3 clams infected with suspicious E. cinetorchis metacercariae out of 200 specimens collected at Kangjin, Chollanam-do were detected, no cercarial and metacercarial infections with E. cinetorchis were observed in field-collected Corbicula specimens. In the susceptibility experiments with laboratory-reared clams, those infected with miracidia of E. cinetorchis did not release their cercariae up to 60 days after infection. To confirm the identity of second intermediate host of E. cinetorchis experimentally, a total of 30 clams were exposed to the cercariae from Segmentina hemisphaerula that had been infected with miracidia of E. cinetorchis. The clams were susceptible to cercariae of E. cinetorchis with an infection rate of 93.3%. Metacercariae from clams taken more than 7 days after cercarial exposure were fed to rats (S/D strain), and adult worms of E. cinetorchis, characterized by 37-38 collar spines on the head crown, were recovered from the ileocecal regions. This is the first report of C. fluminea as a possible second intermediate host of E. cinetorchis.
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Song MS, Park YK, Lee JH, Park K. Induction of glucose-regulated protein 78 by chronic hypoxia in human gastric tumor cells through a protein kinase C-epsilon/ERK/AP-1 signaling cascade. Cancer Res 2001; 61:8322-30. [PMID: 11719466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The M(r) 78,000 glucose-regulated protein (GRP78) can be induced by physiological stresses such as glucose deprivation and hypoxia. In solid tumors, hypoxia can promote malignant progression and confer resistance to irradiation and chemotherapy by altering gene expression. Here, we investigated the molecular mechanisms and signaling pathway involved in the late and prolonged induction of the GRP78 gene by hypoxia in a human gastric cancer cell line, MKN28. Nuclear run-on assays and mRNA stability measurements revealed that transcriptional activation, not stabilization of mRNA, contributed to the dramatic induction of GRP78 gene under hypoxia. Induction of GRP78 by chronic hypoxia was completely abolished by pretreatment with PD98059 [a specific inhibitor of mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK1)] or by overexpression of a dominant-negative MEK1 mutant, demonstrating a direct involvement of ERK in the induction of transcription at the GRP78 promoter under these conditions. Furthermore, hypoxia increased the transcriptional activity of a 12-O-tetradecanoylphorbol-13-acetate response element-like motif on the GRP78 promoter and increased the abundance and DNA binding activity of AP-1 complex composed of c-Jun and c-Fos. A selective protein kinase C (PKC) inhibitor, GF109203X, inhibited the induction of GRP78 gene expression as well as the activities of both ERK and Raf-1. Among six PKC isoforms expressed in MKN28 cells, PKC-epsilon expression level and kinase activity were increased by hypoxia. Transfection of MKN28 cells with a dominant-negative PKC-epsilon blocked the induction of GRP78 through ERK by hypoxia, indicating that PKC-epsilon directly participated in GRP78 induction under hypoxia. Taken together, this study shows that a PKC-epsilon-Raf-1-MEK-ERK-AP1 signaling cascade acts on a 12-O-tetradecanoylphorbol-13-acetate response element-like element to mediate hypoxia-induced GRP78 expression in human gastric cancer cells. We also confirmed in vivo the overexpression of GRP78 in surgical specimens of human primary gastric tumors.
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Park YK, Chi SG, Unni KK. Absence of Bcl10 gene mutations in Ewing's sarcomas. Oncol Rep 2001; 8:1333-5. [PMID: 11605060 DOI: 10.3892/or.8.6.1333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Bcl10 gene was recently isolated from the breakpoint region of t(1;14)(p22;q32) in mucosa-associated lymphoid tissue (MALT) lymphomas. Somatic mutations of Bcl10 were found in not only t(1;14)-bearing MALT lymphomas, but also a wide range of other tumors. To clarify the actual frequency and spectrum of Bcl10 mutations in primary malignant Ewing's sarcomas, we examined 31 cases of Ewing's sarcomas. Polymerase chain reaction single-stranded conformation polymorphism (PCR-SSCP) and sequencing analyses were done. No Bcl10 mutations were found in our series of Ewing's sarcomas. While screening for mutations, we found three polymorphisms at codons 8 exon 1 of the Bcl10 gene. Our results strongly suggest that somatic mutations of Bcl10 are extremely rare in Ewing's sarcomas and do not commonly contribute to their molecular pathogenesis.
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Chai JY, Kim NY, Guk SM, Park YK, Seo M, Han ET, Lee SH. High prevalence and seasonality of cryptosporidiosis in a small rural village occupied predominantly by aged people in the Republic of Korea. Am J Trop Med Hyg 2001; 65:518-22. [PMID: 11716107 DOI: 10.4269/ajtmh.2001.65.518] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The prevalence of Cryptosporidium parvum infection and its seasonality were studied in a small rural village occupied predominantly by aged people in Hwasun-gun, Chollanam-do, Republic of Korea. Fecal samples were collected monthly from November 1996 to October 1997 and examined for enteric parasites. To detect oocysts of C. parvum, the modified acid-fast stain was applied. To determine effects of climatic factors, local weather reports were collected. The overall oocyst prevalence during 1 year was 57.0% (77 of 135), and was significantly higher (P < 0.0001) in aged people--those aged 50-59 years (80.0%) and those aged 60-69 years (69.0%)--than in younger groups. No significant difference (P > 0.05) was noted between men and boys (53.6%) and women and girls (59.5%), but significant (P < 0.05) household clustering was recognized. People aged > 50 years tended to be more repeatedly positive than people in the younger group. The rate varied monthly from 7.8 to 20.0% (average, 12.6%), with significantly higher (P < 0.05) rates in spring than in summer and winter months. This seasonality had little relation with temperature (r = 0.04), but a weak correlation was found with rainfall (r = 0.4). It is of special interest that cryptosporidiosis is highly endemic among the aged population.
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Lee JY, Park YK, Seo SH, So IS, Chung HK, Yang BS, Lee SJ, Park H, Lee YS. 1,4-dioxane-fused 4-anilinoquinazoline as inhibitors of epidermal growth factor receptor kinase. Arch Pharm (Weinheim) 2001; 334:357-60. [PMID: 11822173 DOI: 10.1002/1521-4184(200112)334:11<357::aid-ardp357>3.0.co;2-q] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The 4-anilinoquinazoline PD 153035 (1) is a potential antitumor agent which acts by inhibiting tyrosine kinase activity of epidermal growth factor receptor (EFGR) via competitive binding at the ATP site of enzyme. A series of cyclic analogues of PD 153035 bearing the 1,4-dioxane ring was prepared by reaction of 6-chloro derivative 5 with several aniline nucleophiles. These were evaluated for their ability to inhibit the EGFR kinase and the growth of primary human tumor cell cultures. All of the new 4-anilinoquinazolines exhibited less potency than PD 153035 against EGFR kinase. However, compounds 2b, 2c, 2e, 2g, and 2h showed higher inhibitory activities than PD 153035 against the growth of A431 tumor cell line. The compound 2b containing 3-chloroaniline ring was as potent as PD 153035 against EGFR kinase and showed about 5.4-fold better potency than PD153035 in the inhibition of growth of A431 cell line with good selectivity.
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Park YK, Cho CH, Chi SG, Han CS, Ushigome S, Unni KK. Low incidence of genetic alterations of the p16CDKN2a in clear cell chondrosarcoma. Int J Oncol 2001; 19:749-53. [PMID: 11562750 DOI: 10.3892/ijo.19.4.749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutational inactivation of the cyclin-dependent kinase inhibitors (CDKIs) (p16CDKN2a) tumor suppressor gene has been found in a variety of human tumor types. To investigate the involvement of CDKI abnormality in clear cell chondrosarcoma, alterations of CDKIs were examined in clear cell chondrosarcoma tissues using a quantitative DNA/PCR, PCR-SSCP. Two of 38 specimens (5.2%) we analyzed showed abnormally low levels of p16CDKN2a amplification, suggesting that the allelic deletion of the gene might be low frequent event in progression of this tumor. For detection of subtle sequence alterations such as point mutations, we performed SSCP analysis of the entire coding region of the p16CDKN2a gene. No altered SSCP patterns were found in 38 clear cell chondrosarcoma specimens. This study reflects the very low incidence of genetic alterations of the p16CDKN2a gene in clear cell chondrosarcoma. Therefore, we conclude that the alteration of the p16CDKN2a gene is not involved significantly in the development of clear cell chondrosarcoma.
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96
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Chung PR, Jung Y, Park YK. Segmentina hemisphaerula: a new molluscan intermediate host for Echinostoma cinetorchis in Korea. J Parasitol 2001; 87:1169-71. [PMID: 11695387 DOI: 10.1645/0022-3395(2001)087[1169:shanmi]2.0.co;2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Three species of Planorbidae have been reported from Korea, e.g., Gyraulus convexiusculus, Hippeutis (Helicorbis) cantori, and Segmentina (Polypylis) hemisphaerula. Of these, only H. cantori was reported as the first and second intermediate host for Echinostoma cinetorchis, an important human intestinal parasite in Korea. Segmentina hemisphaerula has also been found to be an intermediate host. In field-collected planorbids, only S. hemisphaerula was found shedding echinostome cercariae and infected with metacercariae of E. cinetorchis, whereas no G. convexiusculus and H. cantori were found to be infected. In experiments with laboratory-bred snails, G. convexiusculus and S. hemisphaerula were susceptible to infection by miracidia of E. cinetorchis, but H. cantori could not be infected. Tadpoles of Rana nigromaculata and laboratory-bred snails of the 3 planorbid species were exposed to E. cinetorchis cercariae shed from field-collected S. hemisphaerula. All tadpoles, S. hemisphaerula, and G. convexiusculus became infected, but no H. cantori were infected. Metacercariae from tadpoles, S. hemisphaerula, and G. convexiusculus were fed to rats per os, and eggs of E. cinetorchis were detected in the rat feces 1 wk later. The rats were killed, and adult E. cinetorchis were recovered from the small intestines. This is the first report of G. convexiusculus as a potential first and second intermediate host and of S. hemisphaerula as a new first and second intermediate host for E. cinetorchis in Korea.
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97
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Kim BH, Bang IS, Lee SY, Hong SK, Bang SH, Lee IS, Park YK. Expression of cspH, encoding the cold shock protein in Salmonella enterica serovar Typhimurium UK-1. J Bacteriol 2001; 183:5580-8. [PMID: 11544220 PMCID: PMC95449 DOI: 10.1128/jb.183.19.5580-5588.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Both Salmonella enterica serovar Typhimurium and Escherichia coli contain the cspH gene encoding CspH, one of the cold shock proteins (CSPs). In this study, we investigated the expression of cspH in S. enterica serovar Typhimurium and found that it was induced in response to a temperature downshift during exponential phase. The cspH promoter was activated at 37 degrees C, and its mRNA was more stable than the other csp mRNAs at 37 degrees C. Moreover, lacZ expression of the translational cspH-lacZ fusion was induced at that temperature. Interestingly, the cspH mRNA had a much shorter 5'-untranslated region than those in the other cold-shock-inducible genes, and the promoter sequence, which was only 55 bp, was sufficient for cspH expression. The 14-base downstream box located 12 bases downstream of the initiation codon of cspH mRNA was essential for its cold shock activation.
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98
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Ito J, Chang FR, Wang HK, Park YK, Ikegaki M, Kilgore N, Lee KH. Anti-AIDS agents. 48.(1) Anti-HIV activity of moronic acid derivatives and the new melliferone-related triterpenoid isolated from Brazilian propolis. JOURNAL OF NATURAL PRODUCTS 2001; 64:1278-1281. [PMID: 11678650 DOI: 10.1021/np010211x] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new triterpenoid named melliferone (1), three known triterpenoids, moronic acid (2), anwuweizonic acid (3), and betulonic acid (4), and four known aromatic compounds (5-8) were isolated from Brazilian propolis and tested for anti-HIV activity in H9 lymphocytes. Moronic acid (2) showed significant anti-HIV activity (EC(50) <0.1 microg/mL, TI >186) and was modified to develop more potent anti-AIDS agents.
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Chung PR, Jung Y, Park YK, Hwang MK. Austropeplea ollula (Pulmonata: Lymnaeidae): a new molluscan intermediate host of a human intestinal fluke, Echinostoma cinetorchis (Trematoda: Echinostomatidae) in Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2001; 39:247-53. [PMID: 11590915 PMCID: PMC2721074 DOI: 10.3347/kjp.2001.39.3.247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Three freshwater snail species of the family Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula and Fossaria truncatula. Out of 3 lymnaeid snail species, A. ollula was naturally infected with the Echinostoma cinetorchis cercariae (infection rate = 0.7%). In the experiments with the laboratory-bred snails, F. truncatula as well as A. ollula was also susceptible to the E. cinetorchis miracidia with infection rates of 25% and 40%, respectively. All of three lymnaeid snail species exposed to the E. cinetorchis cercariae were infected with the E. cinetorchis metacercariae. It is evident that A. ollula acts as the first molluscan intermediate host of E. cinetorchis in Korea, and F. truncatula may be a possible candidate for the first intermediate host of this intestinal fluke. Also, three lymnaeid snail species targeted were experimentally infected with E. cinetorchis metacercariae.
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Kim SJ, Bai GH, Lee H, Kim HJ, Lew WJ, Park YK, Kim Y. Transmission of Mycobacterium tuberculosis among high school students in Korea. Int J Tuberc Lung Dis 2001; 5:824-30. [PMID: 11573893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
SETTING Screening of pulmonary tuberculosis (PTB) patients from high school students by chest radiography and sputum examination. OBJECTIVE To investigate transmission of Mycobacterium tuberculosis among high school students. DESIGN The restriction fragment length polymorphism (RFLP) profiles of M. tuberculosis isolated from PTB patients of high school students were analysed. RESULTS Clustering cases were found in PTB patients screened among high school students. During this study, a single strain with a particular RFLP profile was found most frequently. This particular strain was also the one that was found to be most prevalent among Korean clinical isolates of M. tuberculosis during a nationwide TB prevalence survey previously done in 1995. This strain seems to be the most widely distributed one in Korea, and has thus been designated K1. In addition, by close examination of the RFLP profiles, it was also found that there existed 34 isolates that had RFLP profiles that were similar to the K1 strain. Therefore, K1 and K1-related strains (18.4% of strains, designated as the K family) seem to comprise the most dominant M. tuberculosis strains present in Korea. CONCLUSION Clustering cases were found in PTB patients screened among high school students in Korea. The K family was found to be most prevalent among the clinical isolates of M. tuberculosis found.
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