• Title/Summary/Keyword: Mode of action

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Studies on the Enzyme-releasing Mechanism of Aminoglycosides from Pancreas (Aminoglycosides의 취효소 분비항진기전에 관한 연구)

  • Shim, Ho-Shik;Kim, Kyung-Hwan;Hong, Sa-Suk
    • The Korean Journal of Pharmacology
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    • v.19 no.1
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    • pp.71-76
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    • 1983
  • Aminoglycoside antibiotics are reported to enhance the amylase release from isolated slices of pancreas in vitro and the mode of action of aminoglycosides on amylase release is considered different from those of acetylcholine or cholecystokinin(CCK), i.e., electronmicroscopically intact zymogen granules are appeared in the lumen of pancreatic acini by treatment of aminoglycosides. It is known that atropine blocks the secretagogue effect of acetylcholine, and phenoxybenzamine is reported to block the effects of CCK or its analogue caerulein. Present study was undertaken to investigate the mode of action of aminoglycosides on the amylase release using atropine, phenoxybenzamine and propranolol as a membrane stabilizing agent in slices of chicken pancreas. The results are summarized as follows : 1) Streptomycin and kanamycin increased the amylase release significantly from slices of chicken pancreas. 2) The effect of streptomycin was inhibited by atropine but not by phenoxybenzamine or propranolol. 3) The amylase release by acetylcholine was blocked by atropine tut the effect of cholecystokinin octapeptide(CCK-8) was not influenced by atropine, phenoxybenzamine or propranolol. 4) Pretreatment of streptomycin enhanced the secretagogue effect of acetylcholine or CCK-8. From these results it is suggested that amylase releasing effects of aminoglycosides are mediated in part by cholinergic stimulation and in part by membrane alteration and these effects are enhanced by acetylcholine or cholecystokinin.

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Potential Health Risks from Persistent Organic Pollutants (POPs) in Marine Ecosystem

  • Lee, Youn Ju;Jang, Jae-Seok;Yang, Jae-Ho
    • Journal of Marine Bioscience and Biotechnology
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    • v.8 no.1
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    • pp.10-17
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    • 2016
  • A wide-spread contamination of persistent organic pollutants (POPs) such as dioxins, PCBs, PBDEs in the aquatic ecosystem has generated a great concern over the potential risk for these substances to impact marine biotas and food web. Since a major exposure route of these substances to the humans is through the consumption of food including fish and marine byproducts, the consumption of contaminated products has been a great public health concern. Exposure to POPs has been associated with a wide spectrum of adverse effects including reproductive, developmental, immunologic, carcinogenic, and neurotoxic effects. This review covers the background information of key POPs substances and the recent development of toxicity studies including the mode of action. Because neurotoxic effects of some POPs have been observed in humans at low concentrations, polychlorinated biphenyl (PCB), a representative chemical of POPs, is focused to discuss the possible mode(s) of action for the neurotoxic effects. This review provides the updates of toxicity studies on POPs and paves ways to discuss a possible implication of contaminated marine biota over the human health among the marine biotechnology researchers.

Mode of Inhibitory Action of Amitriptyline on Carbachol-Induced Contraction of Isolated Rabbit Detrusor Muscle

  • Gill, Won-Sik;Shin, Beong-Ho;Kim, Won-Jae;Jeong, Han-Seong
    • The Korean Journal of Physiology
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    • v.26 no.2
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    • pp.137-141
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    • 1992
  • The present study was aimed at elucidating the mode of inhibitory action of tricyclic antidepressants on the smooth muscle. Effects of amitriptyline on the isolated detrusor muscle strips of the urinary bladder of the rabbit were examined. The spontaneous rhythmic movement of the muscle preparation was frequently observed, which was decreased or abolished by addition of amitriptyline $(10^{-5}{\sim}10^{-3}\;M)$. The muscle preparation responded with contraction dose dependently to carbachol, of which dose response curve shifted to the right in the presence of either amitriptyline or atropine. However, amitriptyline produced a nonparallel shift, whereas atropine caused a parallel one. In calcium free medium, the contraction response to carbachol was markedly decreased, which was resumed by the addition of $CaCl_2$ (2.5mM), but not in the presence of either amitriptyline or nifedipine. KCI (60 mM) produced a potent contraction, which was abolished in the presence of amitriptyline or nifedipine. These results suggest that amitriptyline, unlike atropine, not only acts as a noncompetitive antagonist at cholinergic muscarine receptors but also inhibits Ca-influx through the muscle cell membrane.

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Interaction of Norfloxacin with Super-Coiled DNA

  • Hwangbo, Hyun-Jung;Lee, Young-Ae;Park, Jung-Hag;Lee, Yong-Rok;Kim, Jong-Moon;Yi, Seh-Yoon;Kim, Seog K.
    • Bulletin of the Korean Chemical Society
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    • v.24 no.5
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    • pp.579-582
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    • 2003
  • Norfloxacin, that inhibits the action of topoisomerase Ⅱ, binds to wide variety of DNA. The binding mode of this drug to double- and super-coiled DNA (ds- and scDNA) is compared in this study by various spectroscopic methods, including absorption, fluorescence, and circular dichroism(CD) spectroscopy. Hypochromism in the absorption band, negative and positive induced CD bands (respectively in 240-260 nm and 270-300 nm region) are apparent for the norfloxacin that bound to both the dsDNA and scDNA. A decrease in fluorescence is also noticed in the presence of both DNAs. Since the spectroscopic characteristics are the same for both complexes, it is imperative that the binding mode of the norfloxacin is similar in ds- and scDNA. In the presence of $Mg^{2+}$, which is a cofactor in the topoisomerase Ⅱ action, the fluorescence intensity of the scDNA-norfloxacin complex increased and the resulting fluorescence intensity and shape was identical to that in the absence of scDNA. Therefore, the addition of an excess amount of $Mg^{2+}$ may result in the extrusion of norfloxacin from scDNA.

Evaluation of a Streptococcus pneumoniae DNA Vaccine Efficacy (폐렴구균 DNA 백신의 유효성 평가)

  • Lee Jue-Hee;Han Yongmoon
    • YAKHAK HOEJI
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    • v.49 no.6
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    • pp.484-489
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    • 2005
  • Streptococcus pmeumoniae is the leading cause of pneumonia and bacterial meningitis. The current polysaccharide vaccine has been reported ineffective in elderly adults and children less than 2 years of age. Thus, in recent many researchers have been focused on a different approach, DNA vaccine. In our laboratory we developed a Streptococcus pneumoniae DNA (SPDNA) vaccine. This SPDNA vaccine was formulated by inserting the region encoding part of the capsule in the S. pneumoniae into the LAMP-1. In present work, with use of the SPDNA vaccine we attempted to establish a certain methodology useful for evaluation of effectiveness and immunoresponse of a DNA vaccine. Results showed that the subcutaneous route was the most effective for production of antisera specific for S. pneumoniae in mice. By isotyping analyses, IgM, IgGl, IgG2a, and IgG2b were determined. In addition, INF-$\gamma$ and IL-4 were predominantly detected. Combination of those data resulted in a pattern of IgGl < IgG2a=IgG2b and INF$\gamma\>$ >IL-4, which indicates the inmmunity towards the Thl response predominantly; furthermore, the SPDNA vaccination induced resistance of the CD4+T lymphocyte-depleted mice against disseminated pneumococcal infection. These data appear to be possibly due to activation of CDS8+T cell-activation. Taken together, this methodology can be applied for evaluating efficacy and mode of action of a DNA vaccine as minimum critera.

Metabolic Differentiation of Saccharomyces cerevisiae by Ketoconazole Treatment

  • Keum, Young Soo;Kim, Jeong-Han
    • Journal of Applied Biological Chemistry
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    • v.56 no.2
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    • pp.109-112
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    • 2013
  • Azole fungicides are one of the most wide-spread antifungal compounds in agriculture and pharmaceutical applications. Their major mode of action is the inhibition of ergosterol biosynthesis, giving depletion of ergosterol, precursors and abnormal steroids. However, metabolic consequences of such inhibition, other than steroidal metabolitesare not well established. Comprehensive metabolic profiles of Saccharomyces cerevisiae has been presented in this study. Wild type yeast was treated either with glucose as control or azole fungicide (ketoconazole). Both polar metabolites and lipids were analyzed with gas chromatography-mass spectrometry. Approximately over 180 metabolites were characterized, among which 18 of them were accumulated or depleted by fungicide treatment. Steroid profile gives the most prominent differences, including the accumulation of lanosterol and the depletion of zymosterol and ergosterol. However, the polar metabolite profile was also highly different in pesticide treatment. The concentration of proline and its precursors, glutamate and ornithine were markedly reduced by ketoconazole. Lysine and glycine level was also decreased while the concentrations of serine and homoserine were increased. The overall metabolic profile indicates that azole fungicide treatment induces the depletion of many polar metabolites, which are important in stress response.

Anti-Candida Activity of YH-1715R, a New Triazole Derivative

  • Park, Kang-Sik;Kang, Heui-Il;Lee, Jong-Wook;Paik, Young-Ki
    • Journal of Microbiology and Biotechnology
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    • v.14 no.4
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    • pp.693-697
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    • 2004
  • YH-1715R, (2R,3R)-2-(2,4-difluorophenyl)-3-(3-methoxy-1,2,4-isothiazol-3-yl-thio)-1-( 1H-1,2,4-triazol-l-yl)-2-butanol, a new triazole derivative obtained by the structural modification of fluconazole, was found to exhibit potent anti-Candida activity against a wide variety of Candida albicans (C. albicans) (MIC: 0.4-12.5 mg/l). To investigate the mode of action of YH-1715R, its effect on ergosterol biosynthesis in cell-free extracts and whole cells of C. albicans was examined. The inhibitory activity of YH-1715R was approximately ten-fold higher than that of fluconazole. To determine the primary action mechanism of YH-1715R, its inhibitory activity against lanosterol $14\alpha$-demethylase (14$\alpha$-DM), a major target for azole, was measured using gas-liquid chromatography. YH-1715R and fluconazole were found to inhibit 14a-DM with an $IC_{50}$ of 0.015 $\mu$M and 0.01$8\mu$M, respectively, plus the mode of inhibition of YH-1715R and fluconozole was noncompetitive with a $K_i$ of 0.0533$\mu$M and 0.0975$\mu$M.

The Mode of Action and the Positional Specificity of Trichoporon cutaneum Lipase (Trichosporon cutaneum Lipase의 작용기작(作用機作) 및 위치특이성(位置特異性))

  • Kim, Seung-Yeol;Lee, Chun-Yung
    • Applied Biological Chemistry
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    • v.23 no.1
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    • pp.52-57
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    • 1980
  • This study was conducted to clarify the mode of action and the positional specificity of Trichosporon cutaneum lipase during the course of hydrolysis of triolein and monoolein mixture by thin-layer chromatography. 1. The hydrolytic activity of the lipase to oleyl glycerides was in the order of triolein>diolein>monoolein. 2. Both of triolein and diolein were hydrolyzed by the lipase at high and almost the same rate. 3. The hydrolysis of monoolein by the lipase was very slow compared to the other two oleyl glycerides. 4. This lipase appeared to have a very low specificity toward the outer chains of triolein.

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CLINICAL STUDY ON EFFECT OF VIRECHANA KARMA (THERAPEUTIC PURGATION)

  • Bamoriya, Harikishan;Chandil, Shachi;Singh, Rani
    • CELLMED
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    • v.12 no.1
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    • pp.2.1-2.9
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    • 2022
  • The study has been carried out for the comparative analysis of relevant literature in order to highlight the present topic "Clinical study on effect on Virechana karma (therapeutic purgation)". Total no. of 40 cases has been selected from OPD and IPD of Panchakarma department, through proper history taking and clinical examination prior to VirechanaKarma. Only VirechanaKarmaYogya subjects were selected for the VirechanaKarma. Analysis of VirechanKarma on the basis of Vegiki (purgative bouts), Maniki (quantity), Langiki (clinical features) and Aantiki (end product) features were done in this study. In this study a highly significant relief was found in patients i.e. p<0.001 due to Virechana mainly vitiated PittaDosha (the heat energy in the body) and secondary Kaphadosha (mucus) and VataDosha (subtle energy associated with movement) are being expelled out which might have accounted for better relief in VirechanYogya (indicated) individuals (Pitta Pradhan Vyadhi (vitiated pitta), RaktajRoga (hemopoietic diseases), ShodhanYogyaAvastha (detoxification), etc.) in the above group of patients. VirechanaDravyas have properties like Tikshna (hyperfunction), Sukshma(subtle), Ushna (heat), etc. are described in Ayurvedic classics which play a vital role in the mode of action of VirechanaKarma has also been explained under probable mode of action.