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고양이 위 평활근에서 cyclic nucleotide의 자발적 생성과 작용
김명석,이덕주,조양혁,윤신희,한상준,심상수,전중선,백혜정 대한소화기학회 1998 대한소화기학회지 Vol.30 No.6
Background/Aims: The inhibitory neurotransmitter increased the level of cellular cyclic nucleotides and induced smooth muscle relaxation. The aim of this study was to investigate the spontaneous foimation and action of cyclic nucleotides in feline gastric smooth muscle. Methods: Isolated muscle strips were obtained from the fundus of the stomach to measure isometric contraction and muscle cells were prepared with collagenase and papain to measure the level of cyclic nucleotides were also measured by radioimmunoassay. Results: 3-Isobutyl-1-methylxanthine (IBMX) inhibited acetylcholine-induced contraction in a dose dependent manner. Both SQ22536 and methylene blue completely blocked the inhibitory effect of IBMX on acetylcholine-induced contraction. IBMX increased the levels of cAMP and cGMP in muscle cells. The increase in cAMP and cGMP levels by IBMX was inhibited by SQ22536 and methylene blue, respectively. Inhibitory neurotransmitters, such as vasoactive intestinal polypeptide, nitric oxide donor(sodium nitroprusside) and isoprenaline, significantly inhibited acetylcholine-induced contraction via an increase of cyclic nucleotides in the muscle cells. However, antagonists or inhibiiors for inhibitory neurotransmitters did not have an any influence on the inhibitory effect of IBMX. Conclusions: It appears that the formation of cyclic nucleotides including cAMP and cGMP occurs spontaneously in the gastric muscle cells. Therefore, the importance of phosphodiesterase action as well as the formation of the cyclic nucleotides should be considered in evaluating the mechanism of feline gastric smooth muscle relaxation.
착화제 첨가에 따른 웨이퍼 세정 용액 특성 분석 및 금속 용해 거동
김명석,류근혁,이근재 한국분말야금학회 2021 한국분말재료학회지 (KPMI) Vol.28 No.1
The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.
흰쥐 췌장 선포에서 Cholecystokinin 에 의해 유발된 Amylase 유리에 미치는 Somatostatin 의 영향
김명석,최환석,조양혁,윤신희,한상준,심상수,이덕주,이세영 대한소화기학회 1999 대한소화기학회지 Vol.32 No.6
Background/Aims: The inhibitory effect of somatostatin (SS) on cholecystokinin (CCK)-induced amylase release and the role of intracellular cAMP in this process were investigated. Methods: Pancreatic acini were isolated from rat pancreas and treated with solution involving collagenase and then, dispersed. Amylase release was measured. In another set of experiment, cAMP and inosito phosphate (IP) formation were measured. Results: SS-14 inhibited CCK-8-induced amylase release Octreotide, somatostatin analog, also inhibited CCK-8-induced amylase release equipotently. The inhibitory effect of octreotide on CCK-8-induced amylase release was not found in the presence o 8-bromo-cAMP. Forskolin, an adenylyl cyclase activator, potentiated K-8-induced amylase release. However, the amylase release achieved by the simultaneous administration of CCK-8 and octreotide was not altered by forskolin, while the cAMP level in response to the administration of CCK-8 and octreotide was increased significantly by forskolin. Octreotide inhibited the basal cellular cAMP leve significantly, but CCK-8 alone did not exhibit any change. CCK-8-induced IP formation was no changed by octreotide. Tyrosine phosphatase inhibitors did not affect inhibitory action of octreotide on CCK-8-induced amylase release. Conclusions: From the above results, it is concluded that SS inhibits amylase release induced by CCK in dispersed pancreatic acini of rat. A decrease in pancreatic amylase release in response to octreotide may be attributed to inhibited basal cAMP formation Further study is needed to elucidate the related process.