• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10719-10722
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• 2015

Several lines of evidence suggest that MUC5AC genetic polymorphisms might confer susceptibility to H. pylori infection and therefore gastric cancer risk. We here assessed the association of common polymorphisms in the MUC5AC gene with H. pylori seroprevalence using an LD-based tagSNP approach in a north-western Chinese Han population. A total of 12 tagSNPs were successfully genotyped among 281 unrelated ethnic Han Chinese who had no cancer history, and no identifiable gastric disease or genetic disease. No significant association between any alleles, genotypes or haplotypes and H. pylori seroprevalence was observed. Our results suggest that common genetic variations in MUC5AC gene might not make a major contribution to the risk of H. pylori infection.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7255-7260
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• 2015

Background: Recent reports have shown that DLC-1 is widely expressed in normal tissues and is down-regulated in a wide range of human tumors, suggesting it may act as a tumor suppressor gene. We conducted a meta-analysis to determine the correlation between DLC-1 expression and clinicopathological characteristics in cancers. Materials and Methods: A detailed literature search was made for relevant publications from PubMed, EMBASE, Cochrane library databases, Web of Science, CNKI. The methodological quality of the studies was also evaluated. Analyses of pooled data were performed and odds ratios (ORs) were calculated and summarized. Results: Final analysis was performed of 1,815 cancer patients from 19 eligible studies. We observed that DLC- 1 expression was significantly lower in cancers than in normal tissues. DLC-1 expression was not found to be associated with tumor differentiation status. However, DLC-1 expression was obviously lower in advance stage than in early-stage cancers and was more down-regulated in metastatic than non-metastatic cancers. Conclusions: The results of our meta-analysis suggested that DLC-1 expression is significantly lower in cancers than in normal tissues. Aberrant DLC-1 expression may play an important role in cancer genesis and metastasis.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.4
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• pp.219-225
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• 2004

The pelvic ganglia provide autonomic innervations to the various urogenital organs, such as the urinary bladder, prostate, and penis. It is well established that both sympathetic and parasympathetic synaptic transmissions in autonomic ganglia are mediated mainly by acetylcholine (ACh). Until now, however, the properties of ACh-induced currents and its receptors in pelvic ganglia have not clearly been elucidated. In the present study, biophysical characteristics and molecular nature of nicotinic acetylcholine receptors (nAChRs) were studied in sympathetic and parasympathetic major pelvic ganglion (MPG) neurons. MPG neurons isolated from male rat were enzymatically dissociated, and ionic currents were recorded by using the whole cell variant patch clamp technique. Total RNA from MPG neuron was prepared, and RT-PCR analysis was performed with specific primers for subunits of nAChRs. ACh dose-dependently elicited fast inward currents in both sympathetic and parasympathetic MPG neurons $(EC_{50};\;41.4\;{\mu}M\;and\;64.0\;{\mu}M,\;respectively)$. ACh-induced currents showed a strong inward rectification with a reversal potential near 0 mV in current-voltage relationship. Pharmacologically, mecamylamine as a selective antagonist for ${\alpha}3{\beta}4$ nAChR potently inhibited the ACh-induced currents in sympathetic and parasympathetic neurons $(IC_{50};\;0.53\;{\mu}M\;and\;0.22\;{\mu}M,\;respectively)$. Conversely, ${\alpha}-bungarotoxin$, ${\alpha}-methyllycaconitine$, and $dihydro-{\beta}-erythroidine$, which are known as potent and sensitive blockers for ${\alpha}7$ or ${\alpha}4{\beta}2$ nAChRs, below micromolar concentrations showed negligible effect. RT-PCR analysis revealed that ${\alpha}3$ and ${\beta}4$ subunits were predominantly expressed in MPG neurons. We suggest that MPG neurons have nAChRs containing ${\alpha}3$ and ${\beta}4$ subunits, and that their activation induces fast inward currents, possibly mediating the excitatory synaptic transmission in pelvic autonomic ganglia.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.36-36
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• 2002

In the present study, we investigated effects of extracellular zinc (Zn$\^$2＋/) on T-type Ca$\^$2＋/ channel isoforms (${\alpha}$lG, ${\alpha}$lH, and ${\alpha}$lI) stably expressed in HEK 293 cells. Ca$\^$2＋/ currents were measured using 10 mM Ca$\^$2＋/ as a charge carrier under whole cell-ruptured patch configuration. Zn$\^$2＋/ blocked the ${\alpha}$lH currents with a 100- and 200-fold higher potency (IC$\sub$50/ = 2.5 ${\mu}$M) when compared with those for blockade of the ${\alpha}$1G and ${\alpha}$1I currents, respectively.(omitted)

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.217-223
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• 1995

Adenosine 5'-tetraphosphate (ATPP) was identified and quantified in extracts of rabbit platelets by elution of extracts containing authentic adenosine 5'-tetraphosphate and comparison of retention time with nucleotide standards using high-performance liquid chromatography technique. The amount of adenosine 5'-tetraphosphate was $0.62\;nmoles/10^{9}$ cells which was 62-fold lower than that of ATP but only 10-fold lower than that of ADP. During platelet aggregation induced by thrombin, adenosine 5'-tetraphosphate was released to a relatively high extent. The degradation rates and halflives of adenosine 5'-tetraphosphate were measured during incubation of platelets in whole blood, erythrocyte suspension and plasma, respectively. The results suggest that plasma contributes more than blood cells to the catabolism of adenosine 5'-tetraphosphate. The pattern of degradation indicates that ATPP may be degraded mainly to AMP by soluble enzymes in plasma and very slowly to ADP and/or AMP by ectoenzymes on blood cells such as erythrocyte. The nature of the enzymes responsible fer the degradation of adenosine 5'-tetraphosphate is yet to be identified.

• Korean Medical Education Review
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• v.19 no.2
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• pp.101-108
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• 2017

When participating in problem-based learning (PBL), it is important for medical students to generate claims and provide justifications for their claims in small group discussions. This study aimed to investigate the effect of argumentation instruction on medical student learning experiences with PBL. A total of one hundred first-year preclinical students from Inje University College of Medicine, who had attended argumentation instruction, participated in this study. All of the participants completed a 5-point Likert scale questionnaire regarding their learning experiences with PBL, before and after the argumentation instruction. The questionnaire comprised 22 items with eight subcategories: argumentation activity, reflection, integration of basic and clinical science, identification of lack of knowledge, logical thinking, self-directed study, communication, and attitude toward discussion. The collected data were analyzed through a paired-sample t-test. The results of this study found that the argumentation instruction promoted the preclinical students' experiences with argumentation activities, reflection, an integration of basic and clinical science, the identification of their lack of knowledge, logical thinking, and self-directed study, and it increased positive attitudes toward group discussion. The findings suggest argumentation instruction can enhance medical student group discussions and help students achieve the objectives of PBL, including acquisition of basic and clinical science knowledge and development of clinical reasoning and self-directed learning abilities, which can highlight the meaningful learning experiences students have with PBL.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3671-3675
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• 2012

${\beta}$-Amyloid accumulation in the brain is a pathological hallmark of Alzheimer's disease (AD). Since early detection of ${\beta}$-amyloid may facilitate more successful and timely therapeutic interventions, many investigators have focused on developing AD diagnostic reagents that can penetrate the blood-brain barrier (BBB). Oleanolic acid (OA) is a substance found in a variety of plants that has been reported to prevent the progression of AD in mice. In this study, we synthesized and evaluated a new radioligand in which OA was conjugated to lactoferrin (Lf, an iron-binding glycoprotein that crosses the BBB) for the diagnosis of AD. In an in vitro study in which OA-Lf was incubated with ${\beta}$-amyloid (1-42) aggregates for 24 h, we found that OA-Lf effectively inhibited ${\beta}$-amyloid aggregation and fibril formation. In vivo studies demonstrated that $^{123}I$-OA-Lf brain uptake was higher than$^{123}I$-Lf uptake. Therefore, radiolabeled OA-Lf may have diagnostic potential for ${\beta}$-amyloid imaging.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.234-237
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• 1999

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4271-4274
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• 2014

The epithelial to mesenchymal transition (EMT) is a key step during embryonic morphogenesis and plays an important role in drug resistance and metastasis in diverse solid tumors. We previously reported that 48 h treatment of anti-cancer drug doxorubicin could induce EMT in human gastric cancer BGC-823 cells. However, the long term effects of this transient drug treatment were unknown. In this study we found that after 48 h treatment with $0.1{\mu}g/ml$ doxorubicin, most cells died during next week, while a minor population of cells survived and formed colonies. We propagated the surviving cells in drug free medium and found that these long term cultured drug survival cells (abbreviated as ltDSCs) retained a mesenchymal-like cell morphology, and expressed high levels of EMT-related molecules such as vimentin, twist and ${\beta}$-catenin. The expression of chromatin reprogramming factors, Oct4 and c-myc, were also higher in ltDSCs than parental cells. We further demonstrated that the protein level of p300 was upregulated in ltDSCs, and inhibition of p300 by siRNA suppressed the expression of vimentin. Moreover, the ltDSCs had higher colony forming ability and were more drug resistant when compared to parental cells. Our results suggested that an epigenetic mechanism is involved in the EMT of ltDSCs.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.531-535
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• 2011

It was regarded that the $^{31}P$ resonances of inherent nucleotides in $F_1$-ATPase (EF1), as large as 380KDa, could not be observed by $^{31}P$ NMR spectroscopy. However, our $^{31}P$ NMR spectroscopy could differentiate between different nucleotide binding sites on EF1 from Escherichia coli. When EF1 was prepared in the absence of $Mg^{2+}$, EF1 contained only ADP. Multiple $^{31}P$ resonances from $\beta$-phosphates of ADP bound to the EF1 were observed from the enzyme prepared without $Mg^{2+}$, suggesting asymmetry or flexibility amongst nucleotide binding sites. $^{31}P$ resonances from enzyme bound ATP could be observed only from EF1, when the enzyme was prepared in the presence of $Mg^{2+}$. This $Mg^{2+}$ dependent ATP binding was very tight that, once bound, nucleotide could not be removed even after removal of $Mg^{2+}$. $^{31}P$ NMR proved to be a valuable tool for investigating phosphorous related enzymes.