• Title, Summary, Keyword: Organic cation

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Molecular Aspects of Organic Ion Transporters in the Kidney

  • Cha, Seok-Ho;Endou, Hitoshi
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.2
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    • pp.107-122
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    • 2001
  • A function of the kidney is elimination of a variety of xenobiotics ingested and wasted endogenous compounds from the body. Organic anion and cation transport systems play important roles to protect the body from harmful substances. The renal proximal tubule is the primary site of carrier-mediated transport from blood into urine. During the last decade, molecular cloning has identified several families of multispecific organic anion and cation transporters, such as organic anion transporter (OAT), organic cation transporter (OCT), and organic anion-transporting polypeptide (oatp). Additional findings also suggested ATP-dependent organic ion transporters such as MDR1/P-glycoprotein and the multidrug resistance-associated protein (MRP) as efflux pump. The substrate specificity of these transporters is multispecific. These transporters also play an important role as drug transporters. Studies on their functional properties and localization provide information in renal handling of drugs. This review summarizes the latest knowledge on molecular properties and pharmacological significance of renal organic ion transporters.

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Synthesis and Charactrization of Polycaprolactone Nanocomposites Reinforced with Montmorillonite

  • Cho, Sung-Jun
    • Journal of the Korean Ceramic Society
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    • v.41 no.6
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    • pp.425-429
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    • 2004
  • [DEACOOH]-Montmorillonite intercalations complex obtained from Na-Montmorillonite and 10-Carboxy-n-decyldimethylethylammonium bromide (organic cation) was reacted with the monomer ($\varepsilon$-caprolactone) to achieve the [DEACOOH]-$\varepsilon$-caprolactone-Montmorillonite intercalations complex. From this intercalations complex Montmorillonite/Polycaprolactone nanocomposites in which montmorillonite (inorganic polymer) is chemically linked with the polycaprolactone (organic polymer) were formed at 240$^{\circ}C$ by three different methods such as in stoichiometric amounts between monomer and organic cation, in excess of only the monomer and in excess of both organic cation and monomer. The products obtained after polymerization were analyzed with X-ray diffractometer and TEM.

The Transport of Organic Cations in the Small Intestine: Current Knowledge and Emerging Concepts

  • Kim, Moon-Kyoung;Shim, Chang-Koo
    • Archives of Pharmacal Research
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    • v.29 no.7
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    • pp.605-616
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    • 2006
  • A wide variety of drugs and endogenous bioactive amines are organic cations (OCs). Approximately 40% of all conventional drugs on the market are OCs. Thus, the transport of xenobiotics or endogenous OCs in the body has been a subject of considerable interest, since the discovery and cloning of a family of OC transporters, referred to as organic cation transporter (OCTs), and a new subfamily of OCTs, OCTNs, leading to the functional characterization of these transporters in various systems including oocytes and some cell lines. Organic cation transporters are critical in drug absorption, targeting, and disposition of a drug. In this review, the recent advances in the characterization of organic cation transporters and their distribution in the small intestine are discussed. The results of the in vitro transport studies of various OCs in the small intestine using techniques such as isolated brush-border membrane vesicles, Ussing chamber systems and Caco-2 cells are discussed, and in vivo knock-out animal studies are summarized. Such information is essential for predicting pharmacokinetics and pharmacodynamics and in the design and development of new cationic drugs. An understanding of the mechanisms that control the intestinal transport of OCs will clearly aid achieving desirable clinical outcomes.

Beneficial Effect of Scutellaria Balicalensis Georgi Extract ont-Buthylhydroperoxide-Induced Inhibition of Organic Cation in Rabbit Renal Cortical Slices (황금약침액(黃芩藥鍼液)이 토끼의 신장절편에서 t-BHP로 유발된 유기양이온의 이동장애에 미치는 영향(影響))

  • Jo, Mee-hyeong;Jang, Kyung-jeon
    • Journal of Acupuncture Research
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    • v.18 no.4
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    • pp.143-151
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    • 2001
  • Objective : This study was undertaken to determine whether Scutellaria balicalensis Georgi (SbG) extract exerts the protective effect against oxidant-induced alterations in organic cation transport in the renal proximal tubule. Methods : Organic cation transport was estimated by examining alterations in tetraethylammon - ium(TEA) uptake in rabbit renal cortical slices. The slices were treated with 0.2 mM tBHP for 60 min at $37^{\circ}C$. tBHP caused an inhibition in TEA uptake by renal cortical slices. Such an effect was accompanied by depressed Na+-K+-ATPase activity and ATP depletion. tBHP also induced a significant increase in LDH release. Results : SbG prevented tBHP-induced inhibition of TEA uptake in a dose-dependent manner at the concentration ranges of 0.05-0.1%. tBHP-induced inhibition of Na+-K+-ATPase activity and ATP depletion were significantly prevented by 0.05% SbG. tBHP-induced LDH release also was blocked by SbG. tBHP caused a significant increase in lipid peroxidation and its effect was prevented by SbG. Conclusion : These results suggest that SbG prevents oxidant-induced alterations in organic cation transport in rabbit renal cortical slices. Such protective effects of SbG may be attributed to inhibition of peroxidation of membrane lipid.

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A Study on the Synthesis of Organophilic [TEACOOH]-Montmorillonite Intercalations Complex and its Swelling Properties

  • Cho, Sung-Jun
    • Journal of the Korean Ceramic Society
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    • v.39 no.5
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    • pp.427-432
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    • 2002
  • In this research an organic cation, [TEACOOH] Br, with a long alkyl chain was synthesized which will replace the metal ion between the layers of Na-Montmorillonite and an organophilic [TEACOOH]-Montmorillonite intercalations complex was formed by the cation exchange reaction between the Na-Montmorillonite and the synthesized [TEACOOH] Br. After drying of this intercalations complex in high vacuum we have tried to experiment on the probability whether it will form complexes with various swelling solutions such as dist. water, methano, ethanol, toluene, acetonitrile and propionitrile and the corresponding basal sp acings measured were $17.41{\AA}$, $31.90{AA}$, $34.42{AA}$, $30.52{AA}$ and $32.36{AA}$, respectively.

Effects of Organic Materials on Soil Chemical Properties (유기물(有機物)의 시용(施用)이 토양(土壤)의 화학적(化學的) 성질(性質)에 미치는 영향(影響))

  • Oh, Wang-Keun
    • Korean Journal of Soil Science and Fertilizer
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    • v.11 no.3
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    • pp.161-174
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    • 1979
  • A review was made on the effect of organic matter application on the chemical characteristics of soils such as pH, solubilities of minerals, and cation exchange capacity mainly at flooded rice soils. The review can be summarized as follows: 1. Application of organic material such as rice straw and compost in flooded rice soil leads to a temporary lowering of soil pH at the earlier stage of soil reduction, due to the production of various organic acids and carbonic acid. This temporary lowered pH is replaced with the production of alkaline substances such as ammonia as the reduction of soil proceeds. 2. Incorporation of organic materials intensifies the ferrous iron, dissolving various minerals, virtually to the increase in electrical conductivity of soils. 3. Organic materials also play an important role in dissolving soil minerals through the production of various chelating agents. 4. Application of soil organic matter significantly increases cation exchange capacity of soils. 5. Continuous application of rice straw or compost leads to the increase in soil organic matter content to some extent, up to the level of equilibrium. In soils low in organic matter the equilibrium level is attained with five years continuous application of compost. 6. The manner of chemical fertilizer application influences the accumulation of organic matter applied in soils. Low levels of fertilization lowers the accumulation while high levels of fertilization accerelates the accumulation.

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Effect of Renal Ischemia in Tetraethylammonium Transport in Rabbit Renal Coritcal Slices

  • Joo, Woo-Sik;Nam, Yun-Jeong;Jung, Jin-Sup;Kim, Yong-Keun
    • The Korean journal of physiology & pharmacology
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    • v.25 no.2
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    • pp.171-177
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    • 1991
  • This study was carried out to determine effect of acute renal ischemia on transport function of organic cation, tetraethylammonium (TEA), in rabbit kidney proximal tubule. Clamping of the renal artery for 30 and 60 min produced a polyuria which was accompanied by an increase in $Na^+$ excretion. The capacity of kidney cortical slices to accumulate TEA was increased after 30 and 60 min of ischemia. When blood flow was restored for 30 min after 30 and 60 min of ischemia, the augmented TEA uptake was recovered to the control values. Oxygen consumption of cortical slices was stimulated after 30 min of ischemia, whereas it was not altered by 60 min of ischemia. A 90-min ischemia produced a significant inhibition of TEA uptake and tissue oxygen consumption. These results suggest that the basolateral transport system for organic cation persists after ischemic periods of 60 min despite evidence that tubular reabsorptive mechanism of $Na^+$ and water is markedly impaired. This may indicate that the active secretory systems of proximal tubule are more resistant to ischemic injury than the reabsorptive systems.

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Antioxidant Enzyme Activities and Soil Properties of Healthy and Declining Abies koreana (Wils.) in Mt. Halla (한라산 구상나무 건전개체와 쇠약개체의 항산화효소활성 및 토양특성)

  • Lim, Jong-Hwan;Woo, Su-Young;Kwon, Mi Jeong;Kim, Young Kul
    • Journal of Korean Society of Forest Science
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    • v.96 no.1
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    • pp.14-20
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    • 2007
  • In order to examine the differences in antioxidant enzyme activities which represent defence mechanism to stressful environments, and soil properties between healthy and declining (or unhealthy) trees, we selected three sites, Witseorum, Youngsil and Sungpanak (Jindallebat). Antioxidant enzymes including Ascorbate peroxidase (APX) and Glutathione Reductase (GR), forest soil properties including soil texture, soil pH, organic matter, total nitrogen, available phosphate, cation exchange capacity, exchangeable cation content and nutrient contents in leaves of Abies koreana (Korean fir) trees were analyzed. There were no significant differences between healthy and declining trees in GR activity. However, seasonal difference in antioxidant enzyme activity was observed. GR activity was lower in June and August than that of September. Soil chemical and physical properties of each site showed a tendency that organic content, total nitrogen content, available phosphorus, cation exchange capacity and cation content were lower at the site of declining trees than the site of healthy trees.

Effect of Scutellaria baicalensis Georgi Extract on Oxidant-Induced Inhibition of Organic Cation in Rabbit Renal Cortical Slices (황금약침액(黃芩藥鍼液)이 가토(家兎)의 신피질절편(腎皮質切片)에서 Oxidant로 유발된 유기양이온의 이동장애에 미치는 영향(影響))

  • Son, In-suk;Cho, Tae-sung;Kwon, Hae-yon;Jo, Mi-hyeong;Youn, Hyoun-min;Jang, Kyung-jeon;Song, Choon-ho;Abn, Chang-beohm
    • Journal of Acupuncture Research
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    • v.19 no.2
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    • pp.211-220
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    • 2002
  • Objective : This study was undertaken to determine whether Scutellaria baicalensis Georgi extract (SbG) exerts the protective effect against oxidant-induced alterations in organic cation transport in the renal proximal tubule. Methods : Organic cation transport was estimated by examining alterations in tetraethylammonium (TEA) uptake in rabbit renal cortical slices. The slices were treated with 0.2 mM tBHP for 60 min at $37^{\circ}C$. tBl-IP caused an inhibition in TEA uptake by renal cortical slices. Such an effect was accompanied by depressed Na+-K+-ATPase activity and ATP depletion. Result : SbG prevented tBHP-induced inhibition of TEA uptake in a dose-dependent manner at the concentration ranges of 0.05-0.1%. SbG also prevented H2O2-induced reduction in TEA uptake. tBHP-induced inhibition of Na+-K+-ATPase activity and ATP depletion were significantly prevented by 0.05% SbG. Oxidants increased LDH release, which was blocked by SbG. Oxidants caused a significant increase in lipid peroxidation and its effect was prevented by SbG. Conclusion : These results suggest that SbG prevents oxidant-induced alterations in organic cation transport in rabbit renal cortical slices. Such protective effects of SbG may be attributed to inhibition of peroxidation of membrane lipid.

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