• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.37-37
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• 2003

We have shown the $Ca^{2+}$-activated chloride current is present in cardiac myocyte in rabbit pulmonary vein (Kim et al., 2002). This current amplitude was increased as [N $a^{+}$]$_{i}$ was increased and we suggested this chloride current may be involve in the spontaneous action potential frequency change. Since this current is activated by the increase of intracellular $Ca^{2+}$, we would like to test what is the inducer of the increase of [C $a^{2+}$]$_{i}$ between a L-type $Ca^{2+}$-current or a reverse mode of N $a^{+}$-C $a^{2+}$ exchange current. White rabbit (1.5 kg) was used and anesthetized with Ketamin (100 mg/kg). Pulmonary vein (PV) was isolated and sleeve area between left atrium and PV was dissected. Using collagenase (Worthington 0.7 mg/cc), single cardiac myocytes were isolated. In the presence of 15 mM of N $a^{＋}$, three steps of voltage pulses were applied (holding potential : -40 ㎷, -80 ㎷ for 50 msec, 30 ㎷ for 5 msec, 10 ㎷ steps from -70 ㎷ to 60 ㎷). The inward and outward tail current was activated after brief 5 msec prepulse. The outward tail current was blocked by the removal of extracellular chloride substituted by glucuronic acid or by a chloride channel blocker, 5 mM 9-AC. But the inward tail current was still remained even though the amplitude was decreased. The reversal potentials were changed to the direction of the change of chloride equilibrium potential ( $E_{Cl}$ ) but the shift of equilibrium potential was not enough to match to the theoretical equilibrium potential shift. In the presence of L-type $Ca^{2+}$ channel blocker, nifedipine 1 uM, inward tail currents were greatly reduced but the outward current tail currents were still remained. In the presence of N $a^{+}$-C $a^{2+}$ exchange current blocker, 10 uM KB-R7943, the inward and outward tail currents were blocked almost completely. We tried to test the $Ca^{2+}$sensitivity of the chloride current with various [C $a^{2+}$]$_{i}$ in pipette solution from 100 nM to 1 uM but we failed to activate $Ca^{2＋}$-activated chloride currents even though the cell became contracted in the presence of 1 uM $Ca^{2+}$. From these results, we could conclude that the increase of [C $a^{2+}$]$_{i}$ to activate the outward $Ca^{2+}$-activated chloride current was mainly induced by the activation of the reverse mode of N $a^{+}$-C $a^{2+}$ exchanger, But for the increase of [C $a^{2+}$]$_{i}$ to activate the inward tail current, L-type $Ca^{2+}$ current may be the major provoking current. Since the cytosolic increase of [C $a^{2+}$]$_{i}$ through pipette solution have failed to activate $Ca^{2+}$-activated chloride current, this chloride current may have very low $Ca^{2+}$ sensitivity or a comparmental increase $Ca^{2+}$ such as in subsarcolemmal space may activate the chloride current. Since there are several reports and models that the increase of $Ca^{2+}$ in subsarcolemmal space would be over several to tens of uM, both possibility may be valid together.uM, both possibility may be valid together.

• Parasites, Hosts and Diseases
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• v.34 no.3
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• pp.197-206
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• 1996

Water extract of Coix locrvmn seeds (Co-Ex) was separated into several components; dissolved with Tris-Cl buffer and the supernatant (WC 1), ammonium sulfate treatment supernatant (WC2) and the pellet nvc31,9AE column chromatography of WC 1 and the peak portions; WC4, WCS and WC6. Murine peritoneal macrophages in DMEM containing 10% heat-inactivated FCS were infected with tachyzoites of ToxopIQsmc gondii, RH strain, in uifo. By adding modulators such as Co-Ex, WC 1,2,3,4.5,6 and LPS or IFN-γ for 24 hrs . toxoplasmastatic activity of macrophages was examined in relation to nitrite production. Nitrite production of macrophages was enhanced especially in the series of WC2, WC1 and the combination sample (WC1 + WC2 + WC3) by order than other components or fractions (WC4, WC5, WC6) tested . Toxoplasmastatic actions such as percentage of the inacrophages infected by T. gonnii and fold increase of T gondii in macrophages showed retroverse relations with the amount of nitrite production; i.e. as nitric oxide (NO) increased the phagocytic index of macrophages and the fold increase of tachyzoites in macrophages decreased . Nitrite (NO-2) production was increased by adding IFN-γ in all cases together with enhancement of biostatic effects. Through the results obtained, it is speculated that some components other than the non-proteinous and defatted components in Coix lacrwmn seeds may contribute to activate macrophages through induction of NO for the biostatic activity.

• Journal of Chest Surgery
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• v.39 no.7 s.264
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• pp.511-519
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• 2006

Background: Loss of cardiomyocytes in the myocardial infarction leads to regional contractile dysfunction, and necrotized cardiomyocytes in infracted ventricular tissues are progressively replaced by fibroblasts forming scar tissue. Although cardiomyoplasty, or implantation of ventricular assist device or artificial heart was tried in refractory heart failure, the cardiac transplantation was the only therapeutic modality because these other therapeutic strategies were not permanent. Cell transplantation is tried instead of cardiac transplantation, especially bone marrow is the most popular donated organ. But because bone marrow aspiration procedure is invasive and painful, and it had the fewer amounts of cellular population, the adipose tissue is recommended for harvesting of mesenchymal stem cells. Material and Method: After adipose tissues were extracted from abdominal subcutaneous adipose tissue and intra-abdominal adipose tissue individually, the cellular components were obtained by same method. These cellular components were tried to transformation with the various titers of 5-azacytidine to descript the appropriate concentration of 5-azacytidine and possibility of transformation ability of adipose tissue. Group 1 is abdominal subcutaneous adipose tissue and Group 2 is intra-abdominal adipose tissue-retroperitoneal adipose tissue and omentum. Cellular components were extracted by collagenase and $NH_4Cl$ et al, and these components were cultured by non-induction media - DMEM media containing 10% FBS and inducted by none, $3{\mu}mol/L,\;6{\mu}mol/L,\;and\;9{\mu}mol/L$ 5-azacytidine after the 1st and 2nd subculture. After 4 weeks incubation, tile cell blocks were made, immunostaining was done with the antibodies of CD34, heavy myosin chain, troponin T, and SMA. Result: Immunostaining of the transformed cells for troponin T was positive in the $6{\mu}mol/L\;&\;9{\mu}mol/L$ 5-azacytidine of Group 1 & 2, but CD34 and heavy myosin chain antibodies were negative and SMA antibody was positive in the $3{\mu}mol/L\;&\;6{\mu}mol/L$ 5-azacytidne of Group 2. Conclusion: These observations confirm that adult mesenchymal stem cells isolated from the abdominal subcutaneous adipose tissues and intra-abdominal adipose tissues can be chemically transformed into cardiomyocytes. This can potentially be a source of autologous cells for myocardial repair.