• 제목/요약/키워드: Dose attenuation

검색결과 171건 처리시간 0.024초

L-spine Bone SPECT/CT에서 획득된 저선량 CT 영상을 이용한 용적 골밀도 결과의 유용성 (Usefulness of volumetric BMD measurement by using low dose CT image acquired on L-spine Bone SPECT/CT)

  • 고현수;박순기;김은혜;최종숙;정우영;이동윤
    • 핵의학기술
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    • 제27권2호
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    • pp.99-109
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    • 2023
  • Purpose: CT scan makes up for the weak point of the nuclear medicine image having a low resolution and also were used for attenuation correction on image reconstruction. Recently, many studies try to make use of CT images additionally, one of them is to measure the bone mineral density(BMD) using Quantitative CT(QCT) software. BMD exams are performed to scan lumbar and femur with DXA(Dual-Energy X-Ray Absorptiometry) in order to diagnose bone disease such as osteopenia, osteoporosis. The purpose of this study is to identify the usefulness of QCT_BMD analyzed with low dose CT images on L-spine Bone SPECT/CT comparing with DXA_BMD. Materials and Methods: Fifty five women over 50 years old (mean 66.4 ± 9.1) who took the both examinations(L-spine Bone SPECT/CT with SIEMENS Intevo 16 and DXA scan with GE Lunar prodigy advance) within 90 days from April 2017 to July 2022, BMD, T-score and disease classification were analyzed. Three-dimensional BMD was analyzed with low dose CT images acquired on L-spine Bone SPECT/CT scan on Mindways QCT PROTM software and two-dimensional BMD was analyzed on DXA scan. Basically, Lumbar 1-4 were analyzed and the patients who has lesion or spine implants on L-spine were excluded for this study. Pearson's correlation analysis was performed in BMD and T-score, chi-square test was performed in disease classification between QCT and DXA. Results: On 55 patients, the minimum of QCT_BMD was 18.10, maximum was 166.50, average was 82.71 ± 31.5 mg/cm3. And the minimum of DXA-BMD was 0.540, maximum was 1.302, average was 0.902 ± 0.201 g/cm2, respectively. The result shows a strong statistical correlation between QCT_BMD and DXA_BMD(p<0.001, r=0.76). The minimum of QCT_T-score was -5.7, maximum was -0.1, average was -3.2 ± 1.3 and the minimum of DXA_T-score was -5.0, maximum was 1.7, average was -2.0 ± 1.3, respectively. The result shows a statistical correlation between QCT T-score and DXA T-score (p<0.001, r=0.66). On the disease classification, normal was 5, osteopenia was 25, osteoporosis was 25 in QCT and normal was 10, osteopenia was 25, osteoporosis was 20 in DXA. There was under-estimation of bone decrease relatively on DXA than QCT, but there was no significant differences statistically by chi-square test between QCT and DXA. Conclusion: Through this study, we could identify that the QCT measurement with low dose CT images QCT from L-Spine Bone SPECT/CT was reliable because of a strong statistical correlation between QCT_BMD and DXA_BMD. Bone SPECT/CT scan can provide three-dimensional information also BMD measurement with CT images. In the future, rather than various exams such as CT, BMD, Bone scan are performed, it will be possible to provide multipurpose information via only SPECT/CT scan. In addition, it will be very helpful clinically in the sense that we can provide a diagnosis of potential osteoporosis, especially in middle-aged patients.

Development of Natural Antioxidants and Whitening Agents for Cosmeceuticals

  • Kim, Jong-Pyung
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2007년도 Proceedings of The Convention
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    • pp.79-92
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    • 2007
  • Oxidative stress have known to be a risk factor for the degenerative processes and closely related to a lot of diseases. It is well established that antioxidants are good in protection and therapeutic means against oxidative damage. There is increasing interest in natural antioxidants and many natural antioxidants have been found and utilized as the possible protection for various diseases and skin aging. We have screened natural antioxidant agents for cosmeceuticals, nutraceuticals, and drugs as therapeutic and preventive means against oxidative stress, and have developed a number of novel antioxidants from various natural sources. A novel melanin synthesis inhibitor, Melanocin A, isolated from the metabolite of a fungal strain Eupenicillium shearii F80695 inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with $IC_{50}$ value of 9.0 nM and MIC value of $0.9\;{\mu}M$, respectively. Melanocin A also exhibited potent antioxidant activity by scavenging of DPPH and superoxide anion radicals. UV was found to increase the level of hydrogen peroxides and other reactive oxygen species (ROS) in skin tissues. This increase in ROS may not only alter the structure and function of many genes and proteins directly but may also modulate their expressions through signal transduction pathways and, ultimately, lead to skin damage. We investigated the effect of Melanocin A on UV-induced premature skin aging. Firstly, the effect of Melanocin A on UV-induced matrix metalloproteinase (MMP)-9 expression in an immortalized human keratinocyte cell line, HaCaT in vitro was investigated. Acute UV irradiation induced MMP-9 expression at both the mRNA and protein levels and Melanocin A suppressed this expression in a dose-dependent manner. We then investigated UV-induced skin changes in hairless mice in vivo by Melanocin A. Chronic exposure of hairless mouse dorsal skin to UV increased skin thickness and induced wrinkle formation and the gelatinase activities of MMP-2 and MMP-9. Moreover, Melanocin A significantly suppressed UV-induced morphologic skin changes and MMP-2 and MMP-9 expression. These results show that Melanocin A can prevent the harmful effects of UV that lead to skin aging. Therefore, we suggest that Melanocin A should be viewed as a potential therapeutic agent for preventing and/or treating premature skin aging. Terrein is a bioactive fungal metabolite isolated from Penicillium species. Terrein has a relatively simple structure and can be easily synthesized. However, the biologic effects of terrein are comparatively unknown. We found for the first time that terrein potently inhibit melanin production in melanocytes and has a strong hypopigmentary effect in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Treatment of Mel-Ab cells with terrein (10-100 mM) for 4 days significantly reduced melanin levels in a dose-dependent manner. In addition, terrein at the same concentration also reduced tyrosinase activity. We then investigated whether terrein influences the extracellular signal-regulated protein kinase (ERK) pathway and the expression of microphthalmia-associated transcription factor (MITF), which is required for tyrosinase expression. Terrein was found to induce sustained ERK activation and MITF down-regulation, and luciferase assays showed that terrein inhibits MITF promoter activity in a dose-dependent manner. To elucidate the correlation between ERK pathway activation and a decreased MITF transcriptional level, PD98059, a specific inhibitor of the ERK pathway, was applied before terrain treatment and found to abrogate the terrein-induced MITF attenuation. Terrein also reduced the tyrosinase protein level for at least 72 h. These results suggest that terrain reduces melanin synthesis by reducing tyrosinase production via ERK activation, and that this is followed by MITF down-regulation.

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Effect of Rhizoma gastrodiae on oxidative stress in cultured mouse spinal motor neurons

  • Park, Seung-Taeck;Kim, Jeong-Joong;Jeong, Se-Jin;Cho, Chung-Gu;Lee, Kang-Chang;Jang, Chul-Ho;Park, Jae-Hwang;Hong, Gi-Youn;Yoon, Hyang-Suk;Oh, Yeon-Kyun;Oh, Kwang-Su;Min, Bu-Kie;Han, Du-Seok;Baek, Seung-Hwa;Chun, Seung-Ho;Lee, Gap-Sang;Lee, Seong-Keun;Seong, Kang-Kyung;Lee, Geon-Mok;Jeon, Byung-Hoon;Song, Ho-Jun
    • Advances in Traditional Medicine
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    • 제1권2호
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    • pp.59-65
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    • 2000
  • To clarify the toxic effect of oxidative stress, hydrogen peroxide $(H_{2}O_{2})-induced$ neurotoxicity was examined in cultured newborn mouse spinal motor neurons after spinal motor neurons were grown in the media containing various concentrations of glucose oxidase (GO). And also, the protective effect of Rhizoma gastrodiae extract against GO-induced neurotoxicity was evaluated. Cytotoxicity was expressed as a cell viability by 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay. In this study, exposure of motor neurons to GO-induced cell death significantly, in a dose- and time-dependent manners in spinal motor neuron cultures. The decrease in cell viability of motor neurons damaged by GO was proventioned by Rhizoma gastrodiae extract. These results suggest that the neuroprotective effect of Rhizoma gastrodiae extract on GO-induced neurotoxicity may result from a attenuation of $H_{2}O_{2}-induced$ oxidative stress.

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자일로올리고당 함유비율이 다른 설탕이 건강한 성인의 혈당지수와 혈당반응에 미치는 영향 (Effect of different levels of xylooligosaccharide in sugar on glycemic index and blood glucose response in healthy adults)

  • 남혜경;경명옥;서승우;정상원;장문정
    • Journal of Nutrition and Health
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    • 제48권5호
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    • pp.398-406
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    • 2015
  • 본 연구는 8주 동안 건강한 성인남녀를 대상으로 설탕과 자일로 올리고당 함유비율이 다른 설탕 2종의 혈당 반응을 통한 GI를 비교하여 혈당 저하 효과를 확인하였다. 설탕의 GI는 68.9로 기존의 선행연구에서의 GI와 유사하였다. Xylo 7 (Xylooligosaccaride X2~X7 7% 함유), Xylo 10 (Xylooligosaccaride X2~X7 10% 함유)은 포도당이나 설탕에 비해 섭취 후 최대 혈당 상승량이 낮았으며, Xylo 7과 Xylo 10은 통계적으로 유의하게 최대 혈당 상승량이 적었다. Xylo 7와 Xylo 10의 GI는 각각 54.7, 52.5으로 모두 저GI식품에 해당하여 일반 설탕과 비교하여 혈당상승을 유의하게 억제하였다. 또한 체지방률이 높을수록 Xylo 10의 섭취는 GI를 더 낮추는 경향이었다. 따라서 자일로올리고당 유효성분 X2~X7을 함유한 설탕은 혈당상승을 억제하는 건강 기능성을 갖춘 것으로 사료된다.

Vitis amurensis Ruprecht root inhibited ${\alpha}$-melanocyte stimulating hormone-induced melanogenesis in B16F10 cells

  • Jin, Kyong-Suk;Oh, You Na;Hyun, Sook Kyung;Kwon, Hyun Ju;Kim, Byung Woo
    • Nutrition Research and Practice
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    • 제8권5호
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    • pp.509-515
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    • 2014
  • BACKGROUND/OBJECTIVES: The root of Vitis amurensis Ruprecht, a sort of wild-growing grape, has been used in oriental medicine for treatment of skin ailments; however, its dermatological activity is not sufficiently understood. The aim of this study was to investigate tyrosinase inhibitory and anti-melanogenic activities of V. amurensis Ruprecht root methanol extract (VARM) in B16F10 mouse melanoma cells and to attempt to isolate and identify the active compound issued from VARM. MATERIALS/METHODS: Anti-melanogenic activity of VARM was analyzed in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cells through evaluation of antioxidative activity as well as inhibited tyrosinase activity and melanin contents compared with those of kojic acid and arbutin. After anti-melanogenic analysis of VARM, serial fractionation, nuclear magnetic resonance (NMR), and thin layer chromatorgraphy (TLC) were applied for identification of active compounds contained in VARM. RESULTS: VARM significantly inhibited oxidative stress and tyrosinase activity and attenuated ${\alpha}$-MSH-induced melanin production in B16F10 cells. For isolation of active compounds, VARM was fractionated using a series of organic solvents, including dichloromethane ($CH_2Cl_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH). Among fractions showing anti-melanogenic activity, the CH2Cl2 fraction induced the most potent attenuation of melanogenesis without cytotoxicity and the major compound in the $CH_2Cl_2$ fraction was identified as betulinic acid. Betulinic acid isolated from the $CH_2Cl_2$ fraction of VARM significantly attenuated ${\alpha}$-MSH-induced melanogenesis in a dose dependent manner, which was stronger than that of arbutin used as a positive control. CONCLUSIONS: These results indicate that VARM inhibits oxidative stress, tyrosinase activity, and ${\alpha}$-MSH-induced melanogenesis in B16F10 cells, due primarily to the active compound, betulinic acid, in the $CH_2Cl_2$ fraction.

Heat shock protein 90 inhibitor AUY922 attenuates platelet-derived growth factor-BB-induced migration and proliferation of vascular smooth muscle cells

  • Kim, Jisu;Lee, Kang Pa;Kim, Bom Sahn;Lee, Sang Ju;Moon, Byung Seok;Baek, Suji
    • The Korean Journal of Physiology and Pharmacology
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    • 제24권3호
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    • pp.241-248
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    • 2020
  • Luminespib (AUY922), a heat shock proteins 90 inhibitor, has anti-neoplastic and antitumor effects. However, it is not clear whether AUY922 affects events in vascular diseases. We investigated the effects of AUY922 on the platelet-derived growth factor (PDGF)-BB-stimulated proliferation and migration of vascular smooth muscle cells (VSMC). VSMC viability was detected using the XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reagent. To detect the attenuating effects of AUY922 on PDGF-BB-induced VSMCs migration in vitro, we performed the Boyden chamber and scratch wound healing assays. To identify AUY922-mediated changes in the signaling pathway, the phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) 1/2 was analyzed by immunoblotting. The inhibitory effects of AUY922 on migration and proliferation ex vivo were tested using an aortic ring assay. AUY922 was not cytotoxic at concentrations up to 5 nM. PDGF-BB-induced VSMC proliferation, migration, and sprout outgrowth were significantly decreased by AUY922 in a dose-dependent manner. AUY922 significantly reduced the PDGF-BB-stimulated phosphorylation of Akt and ERK1/2. Furthermore, PD98059 (a selective ERK1/2 inhibitor) and LY294002 (a selective Akt inhibitor) decreased VSMC migration and proliferation by inhibiting phosphorylation of Akt and ERK1/2. Greater attenuation of PDGF-BB-induced cell viability and migration was observed upon treatment with PD98059 or LY294002 in combination with AUY922. AUY922 showed anti-proliferation and anti-migration effects towards PDGF-BB-induced VSMCs by regulating the phosphorylation of ERK1/2 and Akt. Thus, AUY922 is a candidate for the treatment of atherosclerosis and restenosis.

Impact of Cellular Genetic Make-up on Colorectal Cancer Cell Lines Response to Ellagic Acid: Implications of small interfering RNA

  • Yousef, Amany I;El-Masry, Omar S;Abdel Mohsen, Mohamed A
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권2호
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    • pp.743-748
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    • 2016
  • Background: $K^-Ras$ activation is an early event in colorectal carcinogenesis and associated mutations have been reported in about 40% of colorectal cancer patients. These mutations have always been responsible for enhancing malignancy and silencing them is associated with attenuation of tumorigenicity. Among downstream effectors are the RAF/MEK/ERK and the PI3K/Akt signaling pathways. PI3K/Akt signaling leads to reduction of apoptosis, stimulated cell growth and enhanced proliferation. Ellagic acid (EA), a naturally occurring antioxidant, has recently emerged as a promising anti-cancer agent. Purpose: To evaluate the impact of cellular genetic makeup of two colon cancer cell lines with different genetic backgrounds, HCT-116 ($K^-Ras^-/p53^+$) and Caco-2 ($K^-Ras^+/p53^-$), on response to potential anti-tumour effects of EA. In addition, the influence of $K^-Ras$ silencing in HCT-116 cells was investigated. Materials and Methods: Cellular proliferation, morphology and cell cycle analysis were carried out in addition to Western blotting for detecting total Akt and p-Akt (at Thr308 and Ser473) in the presence and absence of different concentrations of EA. Cell proliferation was also assessed in cells transfected with different concentrations of $K^-Ras$ siRNA or incubated with ellagic acid following transfection. Results: The results of the present study revealed that EA exerts anti-proliferative and dose-dependent pro-apoptotic effects. Cytostatic and cytotoxic effects were also observed. p-Akt (at Thr308 and Ser473) was downregulated. Moreover, EA treatment was found to (i) reduce $K^-Ras$ protein expression; (ii) in cells transfected with siRNA and co-treated with EA, pronounced anti-proliferative effects as well as depletion of p-Akt (at Thr308) were detected. Conclusions: Cellular genetic makeup ($K^-Ras^-/p53^-$) was not likely to impose limitations on targeting EA in treatment of colon cancer. EA had a multi-disciplinary pro-apoptotic anti-proliferative approach, having inhibited Akt phosphorylation, induced cell cycle arrest and showed an anti-proliferative potential in HCT-116 cells (expressing mutant $K^-Ras$).

갑상선 진료환자 관련 방사성폐기물의 처분을 위한 방사능 측정 및 평가 (Measurement and Estimation for the Clearance of Radioactive Waste with Patients of Thyroid Treatment)

  • 김창범;장성주
    • 한국콘텐츠학회논문지
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    • 제14권6호
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    • pp.255-261
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    • 2014
  • 의료현장에서의 방사성폐기물은 방사성동위원소의 사용량의 증가와 더불어 급격히 늘어나고 있다. 특히, 갑상선 질병의 진단 및 치료용으로 사용량이 증가하고 있는 I-131 핵종의 경우 8.02 일의 짧은 반감기를 가지고 있으며, 관련 폐기물은 모두 자체처분 방법으로 처분하고 있다. 이와 관련하여 국제원자력기구(IAEA)는 개인선량(10 ${\mu}Sv/y$) 및 집단선량(1 man-Sv/y)과 핵종별 농도에 근거하여 각각 폐기물의 규제해제기준을 제시(IAEA Safety Series No 111-P-1.1, 1992 및 IAEA RS-G-1.7, 2004)하였다. 이 연구에서는 의료현장에서 발생하는 I-131 핵종 관련 폐기물을 사용상 종류별로 수집 및 측정하여 방사능농도의 측정 방법 및 절차를 수립한다. 또한, 측정 결과를 바탕으로 핵종의 감쇠 유도식을 산출하고, 이것을 바탕으로 자체처분 가능일자를 산출하여 이론식의 경우와 대비하여 고찰하였다. 측정 결과를 바탕으로 유도 감쇠식을 신정하여 이론적 반감기와 유효 반감기를 비교해 본 결과, I-131 핵종의 이론적 반감기가 유효반감기(7.72일)에 비해 긴 반감기를 가지고 있음을 확인하였다. 측정결과를 바탕으로 한 유효 반감기를 적용한다면, 현재보다 더 짧은 기간 동안 I-131 핵종 폐기물을 보관하였다가 자체처분을 할 수 있다. 이 연구 결과는 ISO 표준으로 추진할 예정이다.

몬테카를로 시뮬레이션을 이용한 광자계수검출기 기반 이중에너지 스펙트럼 유방촬영에서 가중 영상 감산법을 통한 물질분리 (Material Decomposition through Weighted Image Subtraction in Dual-energy Spectral Mammography with an Energy-resolved Photon-counting Detector using Monte Carlo Simulation)

  • 엄지수;강순철;이승완
    • 대한방사선기술학회지:방사선기술과학
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    • 제40권3호
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    • pp.443-451
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    • 2017
  • 유방촬영술은 유방암의 조기검진을 위해 시행되는 대표적인 검사이다. 하지만 유방 구성물질의 물리적 특성에 의존하는 유방촬영상은 병변의 악성 또는 양성 여부에 대한 정보 제공이 불가능하다. 이중에너지 영상 감산법을 시행하는 경우 유방촬영상에서 특정 물질에 대한 정보를 추출할 수 있지만 피폭선량을 증가시킬 뿐만 아니라 물질분리의 정확도를 감소시키는 단점이 있다. 본 연구에서는 물질의 선감약계수를 적용한 유방팬텀을 모사하여 광자계수검출기 기반 이중에너지 유방촬영에서 특정 물질에 대한 가중함수를 적용하여 분리의 정확도를 향상시킬 수 있는 기술을 제안하였다. 그리고 유방팬텀영상으로부터 물질분리의 정확도를 평가하기 위해 대조도 및 잡음 특성을 분석하였다. 분석 결과 이중에너지 가중 영상 감산법의 악성종양에 대한 대조도는 일반적인 유방촬영과 이중에너지 영상 감산법에 비해 각각 0.98, 1.06배로 큰 차이가 없다. 그렇지만 이중에너지 가중 영상 감산법 적용 시 양성종양에 대한 대조도가 0에 근사하기 때문에 양성종양에 대한 악성종양의 상대적인 대조도가 13.54배로 크게 향상된 것으로 확인되었다. 따라서 본 연구에서 제안하는 이중에너지 가중 영상 감산법은 유방촬영 진단의 정확도 향상에 기여할 수 있을 것이다.

Effect of Calmodulin on Ginseng Saponin-Induced $Ca^{2+}$-Activated $Cl^{-}$ Channel Activation in Xenopus laevis Oocytes

  • Lee Jun-Ho;Jeong Sang-Min;Lee Byung-Hwan;Kim Jong-Hoon;Ko Sung-Ryong;Kim Seung-Hwan;Lee Sang-Mok;Nah Seung-Yeol
    • Archives of Pharmacal Research
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    • 제28권4호
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    • pp.413-420
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    • 2005
  • We previously demonstrated the ability of ginseng saponins (active ingredients of Panax ginseng) to enhance $Ca^{2+}$-activated $Cl^{-}$ current. The mechanism for this ginseng saponin-induced enhancement was proposed to be the release of $Ca^{2+}$ from $IP_{3}-sensitive$ intracellular stores through the activation of PTX-insensitive $G\alpha_{q/11}$ proteins and PLC pathway. Recent studies have shown that calmodulin (CaM) regulates $IP_{3}$ receptor-mediated $Ca^{2+}$ release in both $Ca^{2+}-dependent$ and -independent manner. In the present study, we have investigated the effects of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current responses in Xenopus oocytes. Intraoocyte injection of CaM inhibited ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement, whereas co-injection of calmidazolium, a CaM antagonist, with CaM blocked CaM action. The inhibitory effect of CaM on ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement was dose- and time-dependent, with an $IC_{50} of 14.9\pm3.5 {\mu}M$. The inhibitory effect of CaM on saponin's activity was maximal after 6 h of intraoocyte injection of CaM, and after 48 h the activity of saponin recovered to control level. The half-recovery time was calculated to be $16.7\pm4.3 h$. Intraoocyte injection of CaM inhibited $Ca^{2+}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement and also attenuated $IP_{3}$-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. $Ca^{2+}$/CaM kinase II inhibitor did not inhibit CaM-caused attenuation of ginseng saponin-induced $Ca^{2+}$-activated $Cl^{-}$ current enhancement. These results suggest that CaM regulates ginseng saponin effect on $Ca^{2+}$-activated $Cl^{-}$ current enhancement via $Ca^{2+}$-independent manner.