• Journal of the Korean Vacuum Society
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• v.3 no.3
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• pp.296-304
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• 1994

Pt-Ni 합금의 질서-무질서 상전이 현상과 {111}표면에서의 편석현상을 Ising 형태의 해밀토니안 을 이용한 몬테 카를로 시뮬레이션으로 연구하였다. 표면 편석 현상을 질서-무질서 상전이 현상과 연관 시켜 고려함으로서 기존의 편석과 질서에 관한 실험 결과들을 좀 더 구체적으로 이해하게 하였다. PtxNi1-x{111} 의 경우 표면편석 현상은 덩어리의 상전이 온도 이전에서부터 나타나며 이는 표면이 덩어 리의 단면 형태의 질서와는 다른 화학적 질서를 갖는 특징에 기인하는 것임을 보았다. 표면 근방에만 한정된 진동하는 형태의 표면 편석현상을 보았고 이는 실험결과들과도 잘 일치하는 것을 알 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.413-423
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• 1997

The importance of the kidney in the development of hypertension was first demonstrated by Goldblatt and his colleagues more than fifty years ago. Many hormones and other regulatory factors have been proposed to play a major role in the development of hypertension. Among these factors angiotensia II (ANG II) is closely involved in renal hypertension development since it directly regulates $Na^+$ reabsorption in the renal proximal tubule. Thus the aim of the present study was to examine signaling pathways of low dose of ANC II on the $Na^+$ uptake of primary cultured rabbit renal proximal tubule cells (PTCs) in hormonally defined seum-free medium. The results were as follows: 1) $10^{-11}$ M ANG II has a significant stimulatory effect on growth as compared with control. Alkaline phosphatase exhibited significantly increased activity. However, leucine aminopeptidase and ${\gamma}-glutamyl$ transpeptidase activity were not significant as compared with control. In contrast to $10^{-11}$ M ANG II stimulated $Na^+$ uptake $(108.03{\pm}2.16% of that of control)$, $10^{-9}$ M ANG II inhibited ($92.42{\mu}2.23%$ of that of control). The stimulatory effect of ANG II on $Na^+$ uptake was amiloride-sensitive and inhibited by losartan (ANG II receptor subtype 1 antagonist) and not by PD123319 (ANG II receptor subtype 2 antagonist). 2) Pertussis toxin (PTX) alone inhibited $Na^+$ uptake by $85.52{\pm}3.52%$ of that of control. In addition, PTX pretreatment prevented the AMG II-induced stimulation of $Na^+$ uptake. 8-Bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), forskolin, and isobutylmethylxanthine (IBMX) alone inhibited $Na^+$ uptake by $88.79{\pm}2.56,\;80.63{\pm}4.38,\;and\;84.47{\pm}4.74%$ of that of control, respectively, and prevented the ANG II-induced stimulation of $Na^+$ uptake. However, $10^{-11}$ M ANG II did not stimulate cAMP production. 3) The addition of 12-O-te-tradecanoylphorbol-13-acetate (TPA, 0.01 ng/ml) to the PTCs produced significant increase in $Na^+$ uptake ($114.43{\pm}4.05%$ of that of control). When ANG II and TPA were added together to the PTCs, there was no additive effect on $Na^+$ uptake. Staurosporine alone had no effect on $Na^+$ uptake, but led to a complete inhibition of ANG II- or TPA-induced stimulation of Na'uptake. ANG II treatment resulted in a $111.83{\mu}4.51%$ increase in total protein kinase C (PKC) activity. In conclusion, the PTX-sensitive PKC pathway is the main signaling cascade involved in the stimulatory effects of ANG II on $Na^+$ uptake in the PTCs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.926-931
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• 2007

Diarrhetic shellfish poisons (DSP) such as okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-1(PTX1), PTX2, PTX6 and yessotoxin (YTX) were determined simultaneously by LC-MS/MS and mouse bioassay in the shellfishes (oyster, mussel, Washington purple clam, ark shell, scallop and short necked clam) collected at Tongyeong, from March to September, 2006. Oyster and mussel were found to contain DSP (0.05${\sim}$0.1 MU/g) in March by mouse bioassay; however, no DSP components were detected on the LC-MS/MS. Also, a small amount of DTX1 (0.05 ${\mu}g/g$) in mussel (June) and OA (0.01${\sim}$0.02 ${\mu}g/g$) in 5 species of shellfishes(August) were determined by LC-MS/MS.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.66-83
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• 2002

Recently, we have provided evidence that ginsenosides, the active components of Panax ginseng, utilize pertussis toxin (PTX)-insensitive $G{\alpha}_{q/11}-phospholipase\;C-{\beta}3(PLC-{\beta}3)$ signal transduction pathway for the enhancement of $Ca^{2+}-activated\;Cl^{-}$ current in the Xenopus oocyte (British J. Pharmacol. 132, 641-647, 2001; JBC 276, 48797-48802, 2001). Other investigators have shown that stimulation of receptors linked to $G{\alpha}-PLC$ pathway inhibits the activity of G proteincoupled inwardly rectifying $K^+$ (GIRK) channel. In the present study, we sought to determine whether ginsenosides influenced the activity of GIRK 1 and GIRK 4 (GIRK 1/4) channels expressed in the Xenopus oocyte, and if so, the underlying signal transduction mechanism. In oocyte injected with GIRK 1/4 channel cRNAs, bath-applied ginsenosides inhibited high potassium (HK) solution-elicited GIRK current $(EC_{50}:4.9{\pm}4.3\;{\mu}g/ml).$ Pretreatment of the oocyte with PTX reduced the HK solution-elicited GIRK current by $49\%,$ but it did not alter the inhibitory ginsenoside effect on GIRK current. Prior intraoocyte injection of cRNA(s) coding $G{\alpha}_q,\;G{\alpha}_{11}\;or\;G{\alpha}_q/G{\alpha}_{11},\;but\;not\;G{\alpha}_{i2}\;or\;G{\alpha}_{oA}$ attenuated the inhibitory ginsenoside effect. Injection of cRNAs coding $G{\beta}_{1{\gamma}2}$ also attenuated the ginsenoside effect. Similarly, injection of the cRNAs coding regulators of G protein signaling 1, 2 and 4 (RGS1, RGS2 and RGS4), which interact with $G{\alpha}_i\;and/or\;G{\alpha}_{q/11}$ and stimulates the hydrolysis of GTP to GDP in active GTP-bound $G{\alpha}$ subunit, resulted in a significant reduction of ginsenoside effect on GIRK current. Preincubation of GIRK channel-expressing oocyte in PLC inhibitor (U73122) or protein kinase C (PKC) inhibitor (staurosporine or chelerythrine) blocked the inhibitory ginsenoside effect on GIRK current. On the other hand, intraoocyte injection of BAPTA, a free $Ca^{2+}$ chelator, had no significant effect on the ginsenoside action. Taken together, these results suggest that ginsenosides inhibit the activity of GIRK 1/4 channel expressed in the Xenopus oocyte through a PTX-insensitive and $G{\alpha}_{q/11}$-,PLC-and PKC-mediated signal transduction pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1125-1131
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• 2014

Background: Schistosomiasis is a parasitic disease causing chronic ill health in humans with a serious consequences for socio-economic development in tropical and subtropical regions. There is also evidence linking Schistosoma mansoni to colonic carcinoma occurrence. The aim of this study was to evaluate some inflammatory and oxidative stress biomarkers, as well as L-fucose as linkers between intestinal schistosomiasis and colonic dysplasia development in mice. Materials and Methods: This study was conducted upon 80 mice that were divided the control group (10 non infected mice) and infected group which was subdivided into 7 sub-groups (10 mice each) according to the time of sacrifaction in the post infection (p.i.) period, 10 mice being sacrificed every two weeks from 6 weeks p.i. to 18 weeks p.i. Tumor necrosis factor alpha (TNF-${\alpha}$), inducible nitric oxide synthase (iNOS), and pentraxin 3 (PTX3) levels were estimated by immunoassay. The L-fucose level, and thioredoxin reductase (TrxR) and lactate dehydrogenase (LDH) activities were also evaluated in colonic tissue. Results: The current study revealed statistically significant elevation in the studied biochemical markers especially at 16 and 18 weeks p.i. The results were confirmed by histopathological examination that revealed atypical architectural and cytological changes in the form of epithelial surface serration and nuclear hyper-chromatizia at 14, 16 and 18 weeks p.i. Conclusions: inflammation, oxidative stress and L-fucose together may form an important link between Schistosomal mansoni infection and colonic dysplasia and they can be new tools for prediction of colonic dysplasia development in experimental schistosomiasis.

• BMB Reports
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• v.44 no.3
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• pp.205-210
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• 2011

Insulin has antiapoptotic activity in various cell types. However, the signaling pathways underlying the antiapoptotic activity of insulin is not yet known. This study was conducted to determine if cAMP affects the antiapoptotic activity of insulin and the activity of PI3K and ERK in CHO cells expressing human insulin receptors (CHO-IR). Insulin-stimulated ERK activity was completely suppressed by cAMP-elevating agents like as pertussis toxin (Ptx) and cholera toxin (Ctx) after 4 h treatment. Insulin-stimulated PKB/Akt activity was not affected at all. Ptx treatment together with insulin increased the number of apoptotic cells and the degree of DNA fragmentation. Ctx or 8-br-cAMP treatment also increased the number of apoptotic cells and stimulated the cleavage of caspase-3 and the hydrolysis of PARP. Taken together, cAMP antagonizes the antiapoptotic activity of insulin and the main target molecule of cAMP in this process is likely ERK, not PI3K-dependent PKB/Akt.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.83-89
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• 2016

Sepsis is the life-threatening response to infection which can lead to tissue damage, organ failure, and death. In the current study, the effect of orally administered D-glucose on the mortality and the blood glucose level induced by D-Galactosamine (GaLN)/lipopolysaccharide (LPS)-induced sepsis was examined in ICR mice. After various amounts of D-glucose (from 1 to 8 g/kg) were orally fed, sepsis was induced by injecting intraperitoneally (i.p.) the mixture of GaLN /LPS. Oral pre-treatment with D-glucose dose-dependently increased the blood glucose level and caused a reduction of sepsis-induced mortality. The oral post-treatment with D-glucose (8 g/kg) up to 3 h caused an elevation of the blood glucose level and protected the mortality observed in sepsis model. However, D-glucose post-treated at 6, 9, or 12 h after sepsis induction did not affect the mortality and the blood glucose level induced by sepsis. Furthermore, the intrathecal (i.t.) pretreatment once with pertussis toxin (PTX; $0.1{\mu}g/5ml$) for 6 days caused a reduction of D-glucose-induced protection of mortality and hyperglycemia. Furthermore, once the hypoglycemic state is continued up to 6 h after sepsis initiated, sepsis-induced mortality could not be reversed by D-glucose fed orally. Based on these findings, it is assumed that the hypoglycemic duration between 3 and 6 h after the sepsis induction may be a critical time of period for the survival. D-glucose-induced protective effect against sepsis-induced mortality appears to be mediated via activating PTX-sensitive G-proteins in the spinal cord. Finally, the production of hyperglycemic state may be critical for the survival against the sepsis-induced mortality.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.281-290
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• 1996

Purpose : Chest irradiation leads to a significant cardiac injury in a number of patients. To prevent, or to reduce the risk of radiation-induced cardiac injury, pentoxifylline(PTX), a haemorrheologic agent that improves the blood flow through small blood capillaries has been employed. Materials and Methods : One hundred and eighty ICR mice were divided into three study groups: control, radiation alone, and radiation-pentoxifylline. Each group was subdivided into 12 subgroups: 1 3, 6 and 10 days and 2, 3, 4, 6, 8, 12, 16 and 20 weeks by observation Period after irradiation. The total 15Gy of radiation was delivered in a single fraction through anterior mediastinal port. Pentoxifylline was injected subcutaneously daily 50mg/kg to the back of the mice from the first day of irradiation throughout the observation period. The mice of each group after a certain observation period were sacrificed and sectioned for histopathologic examination of the heart. Result : The findings of acute radiation-induced carditis i.e., heterophilic infiltration and vacuolization and ballooning of endothelial cells were observed upto 6 weeks and reduced sharply afterwards. The late radiation effects including pericarditis with mononuclear cell infiltration, pericardial fibrosis, endothelial cell changes, myocardial degeneration and fibrosis present from 4 weeks onwards after irradiation but with various degree of severity. The overall process of pathologic changes of radiation-pentoxifylline group was similar to those of radiation alone group but the duration of acute stage was relatively short and the severity of late cardiac toxicity was much lesser compared with those of radiation alone group. Conclusion : Pentoxifylline can effectively reduce the late radiation-induced cardiac injury and reslve the acute effects relatively rapidly.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5587-5591
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• 2012

Objective: This study was performed to evaluated the efficacy and safety of continuous infusional paclitaxel and 5-Fu as first-line chemotherapy in patients with advanced esophageal squamous cell cancer (ESCC). Methods: A total of 22 patients with advanced esophageal squamous cell cancer with no indications for surgery and radiation therapy, or recurrent patients were enrolled from October 2008 to November 2010. All were treated with PTX 20 $mg/m^2$ was administered through a 16 hours continuous intravenous infusion on days 1 to 3, 8 and 9. DDP 3.75 $mg/m^2$ was given on days 1 to 4 and 8 to 11, continuous infusional 5-FU over 24-hours on days 1 to 5 and 8 to 12 at a dose of 375 $mg/m^2$, and folacin 60 mg orally synchronized with 5-Fu. The treatment was repeated every 21 days for at least two cycles. Results: 22 cases of all enrolled patients could be evaluated for the effect of treatment: 2 cases were CR, 9 cases PR, 5 cases SD and 2 cases PD, giving an overall response rate of 68.2%(15/22). The median time to progression was 7.0 months. The adverse reactions related to chemotherapy were tolerable; the most common toxic effects were marrow depression, alopecia, and fatigue. Conclusion: Low-dose continuous infusional PTX over 16-hours and 5-fu over 24-hours is a promising regimen with good tolerability in treating patients with advanced esophageal squamous cell cancer.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.6
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• pp.549-555
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• 2015

We attempted to investigate molecular mechanisms underlying phenotypic change of vascular smooth muscle cells (VSMCs) by determining signaling molecules involved in chemokine production. Treatment of human aortic smooth muscle cells (HAoSMCs) with thrombin resulted not only in elevated transcription of the (C-C motif) ligand 11 (CCL11) gene but also in enhanced secretion of CCL11 protein. Co-treatment of HAoSMCs with GF109230X, an inhibitor of protein kinase C, or GW5074, an inhibitor of Raf-1 kinase, caused inhibition of ERK1/2 phosphorylation and significantly attenuated expression of CCL11 at transcriptional and protein levels induced by thrombin. Both Akt phosphorylation and CCL11 expression induced by thrombin were attenuated in the presence of pertussis toxin (PTX), an inhibitor of Gi protein-coupled receptor, or LY294002, a PI3K inhibitor. In addition, thrombin-induced production of CCL11 was significantly attenuated by pharmacological inhibition of Akt or MEK which phosphorylates ERK1/2. These results indicate that thrombin is likely to promote expression of CCL11 via PKC/Raf-1/ERK1/2 and PTX-sensitive protease-activated receptors /PI3K/Akt pathways in HAoSMCs. We propose that multiple signaling pathways are involved in change of VSMCs to a secretory phenotype.