• Molecules and Cells
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• v.21 no.1
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• pp.42-51
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• 2006

We investigated the mechanism of contraction induced by S1P in esophageal smooth muscle cells. Western blot analysis demonstrated that $S1P_1$, $S1P_2$, $S1P_3$, and $S1P_5$ receptors existed in the cat esophagus. Only penetration of EDG-5 ($S1P_2$) antibody into permeabilized cells inhibited S1P-induced contraction. Pertussis toxin (PTX) also inhibited contraction, suggesting that it was mediated by $S1P_2$ receptors coupled to a PTXsensitive $G_i$ protein. Specific antibodies to $G_{i2}$, $G_q$ and $G_{\beta}$ inhibited contraction, implying that the S1P-induced contraction depends on PTX-insensitive $G_q$ and $G_{\beta}$ dimers as well as the PTX-sensitive $G_{i2}$. Contraction was not affected by the phospholipase $A_2$ inhibitor DEDA, or the PLD inhibitor ${\rho}$-chloromercuribenzoate, but it was abolished by the PLC inhibitor U73122. Incubation of permeabilized cells with $PLC{\beta}3$ antibody also inhibited contraction. Contraction involved the activation of a PKC pathway since it was affected by GF109203X and chelerythrine. Since $PKC{\varepsilon}$ antibody inhibited contraction, $PKC{\varepsilon}$ may be required. Preincubation of the muscle cells with the MEK inhibitor PD98059 blocked S1P-induced contraction, but the p38 MAP kinase inhibitor SB202190 did not. In addition, co-treatment of cells with GF 109203X and PD98059 did not have a synergistic effect, suggesting that these two kinases are involved in the same signaling pathway. Our data suggest that S1P-induced contraction in esophageal smooth muscle cells is mediated by $S1P_2$ receptors coupled to PTX-sensitive $G_{i2}$ proteins, and PTX-insensitive $G_q$ and $G_{\beta}$ proteins, and that the resulting activation of the $PLC{\beta}3$ and $PKC{\varepsilon}$ pathway leads to activation of a p44/p42 MAPK pathway.

• 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.

• Clinical and Experimental Pediatrics
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• v.51 no.6
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• pp.610-615
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• 2008

Purpose : Idiopathic thrombocytopenic purpura (ITP) is a relatively common hematological disease in children. It generally occurs after exposure to a common viral infection episode; however, it may occasionally follow immunization with measles, measles-mumps-rubella (MMR), hepatitis B (HBV), influenza, diphtheria-tetanus-pertussis (DTP), or chickenpox vaccines. In this study, the incidence, clinical characteristics, and treatment outcome of vaccination-associated ITP were investigated and compared with non-vaccination-associated ITP. Methods : The admission records of 105 pediatric ITP patients between 0-14 years of age admitted to Department of Pediatrics, Wonkwang University Hospital from January 1994 to July 2007 were retrospecitively reviewed. Patients were grouped into a vaccination-associated group and a non-vaccination-associated group according to vaccination history within the previous 1 month, and various clinical features between the two groups were statistically analyzed. Results : Thirteen patients (12%) had a preceding vaccination. Eight had received DTP vaccination, 2 had received hepatitis B, and 1 each had received influenza, MMR, and Japanese B encephalitis vaccination. However, none of the patients had a recurrent thrombocytopenia after subsequent vaccinations. In the vaccination-associated group, the age was significantly lower, anemia was more common, and the risk period with blood platelet count $<20{\times}10^9/L$ was significantly shorter than for the in non-vaccination-associated group. Also, wet purpura was less prominent and the remission within 1month was more frequently achieved in the vaccination-associated ITP group. Conclusion : Vaccination-associated ITP patients showed mild symptoms with a more benign and shorter lasting course than non-vaccination-associated ITP patients. Moreover, platelet count assessment at the time of the next immunization may not be necessary.

• Clinical and Experimental Pediatrics
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• v.45 no.10
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• pp.1234-1240
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• 2002

Purpose : This study was carried out to obtain the vaccination rate and age appropriateness of vaccination in children under five years of age in Jeonbuk province. Methods : Eight hundred and fifty infants and children were enrolled in this study. Vaccination rate(Number of vaccinees/Number of subjects), places of vaccination, age appropriateness of vacination were examined by either vaccine record review or interview with parents or guardians. Results : The salient features of the findings were as follows : All subjects were aged under five and mostly under two years of age(68.8%). Places of vaccination were health centers or subcenters( 50.4%), private clinics(44.3%), and general hospitals(5.3%). Routine vaccinations such as BCG, hepatitis B vaccine(HBV), diphtheria, tetanus, acellular pertussis(DTaP) and Trivalent Oral Polio Vaccine(TOPV), measles, mumps, rubella(MMR), and Japaneses B encephalitis(JBE) were vaccinated mostly in health centers or subcenters, while chickenpox(CHP) and haemophilus influenzae vaccines(Hib), which are not routine in Korea, were vaccinated in private clinics. The vaccination rates of BCG(99.2%), HBV(93.5%) and DTaP(96.1%) were very high. But those of MMR(83.7%), CHP(72.5%), JBE(50.2%), and Hib(15.8%) were lower than expected. Considering the age appropriateness of vaccination, some infants and children were not appropriately vaccinated(vaccination rate/age appropriateness of vaccine; HBV, 93.5%/88.4% : DTaP, 94.6%/73.1% : JBE, 50.2%/ 18.5%). Conclusion : The vaccination rate of BCG, HBV, DTaP and TOPV was very high, but MMR, CHP, JBE, and Hib vaccination rate was not high enough to be able to protect against epidemic. We should pay more attention to vaccinating children, and there is a need for a program that will enhance coverage for vaccines.