• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.50-57
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• 1993

This study characterized the effect of liver injury produced by hepatotoxicants on the biliary and urinary excretion of acetaminophen(AA) metabolites. Liver damage was produced in male S.-D. rats, 24 hr after dosing with carbon tetrachloride(4CCl_4,$ 0.75 mι/kg, ip) or thioacetamide(TA, 200 mg/kg, ip), or 16 hr after administration of cadmium chloride(4CdCl_2,$ 3.9 mg/kg, iv). Liver damage without renal injury was confirmed by measuring serum enzymes, creatinine and BUN levels as well as by histopathological examination. AA and its metabolites were measured for 3 hr by HPLC in rats injected iv with 1 mmo1/kg of AA. The excreted amounts of AA-glucuronide into bile were reduced to 60~70% of control rats by hepatotoxicants, but did not change urinary excretion of AA-glucuronide and AA-sulfate. Treatments with $CCl_4,\; CdCl_2$ and TA decreased the total (biliary plus urinary) excretion of thioethers of AA(30~50% of control), suggesting that these toxicants decrease cytochrome P-450-mediated toxification of AA. However, treatments of $CdCl_2$and TA markedly enhanced the excretion of AA-mercapturate into urine. Thus, 4CdCl_2$ and TA not only influence the formation of AA-glutathione, but may also alter the excretory routes (i.e. bile and urine) for the elimination of AA-metabolite.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.160-165
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• 1993

The effects of Glycyrrhizae Radix (GR) on the metabolism of acetaminophen (AA) were examined in male Sprague-Dawley rats. The methanol extract of GR (500 mg/kg) was administered orally to rats for 6 days. AA and its metabolites excreted in bile, urine and blood within 120 min after dosing of AA (150 mg/kg, i.v.) were assayed by HPLC. Treatment of rats with the methanol extract of GR significantly increased the cumulative biliary excretion of AA-glucuronide (156% of the control) and decreased that of AA-sulfate (63% of the control). The cumulative urinary excretion of AA-glucuronide was also significantly increased to 132% of the control. GR treatment significantly increased total (biliary plus urinary) excretion of AA-glucuronide (172% of the control) without influencing thioether and sulfate conjugates of AA. The results clearly show that GR enhances UDP-glucuronosyl transferase-mediated detoxication of AA, but may not influence sulfotrans-ferase-mediated and cytochrome P-450-mediated metabolites formation.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.261-269
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• 1998

Concomitant administration of a single acute dose of ethanol (4 g/kg) protected mice from the hepatocellular injury observed upon administration of a large dose of acetaminophen (400 mg/kg). This was evidenced by the normal histological appearances of liver sections and by the lowered serum aminotransferase activities in mice treated with ethanol and acetaminophen together. In the mice treated with acetaminophen alone, along with the hepatic necrosis, the hepatic microsomal aminopyrine N-demethylase activity was decreased. However, co-administration of ethanol prevented this acetaminophen dependent inhibition on the microsomal mixed function oxidase activity. Pharmacokinetic studies indicated that the concentration of un-metabolized drug in the blood was increased in the ethanol treated mice. Furthermore, upon co-administration of ethanol, although the biliary levels of acetaminophen metabolites (glucuronide, sulfate and cysteine conjugates) were decreased, the level of unmetabolized acetaminophen was increased. Our findings suggest that co-administration of an acute dose of ethanol reduces the degree of hepatocellular necrosis produced by a large dose of acetaminophen and this ethanol dependent protection is, in major part, afforded by suppression of the hepatic microsomal mixed function oxidase activity catalyzing the metabolic activation of acetaminophen.

• Korean Journal of Acupuncture
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• v.20 no.4
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• pp.41-52
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• 2003

Objectives : Circii Herba has been used as a natural drug for the treatment of stress digestive system disease. The aim of this study is to investigate the role of Circii Herba aqua-acupuncture solution (CHAS) in experimental oxidative liver injury. Methods : In order to investigate the effects of CHAS on acute liver injury, male ICR mice were pretreated with CHAS(0.2 ml/mouse/day) at the loci of BL18 and CV12 for 6days, starved for 24hrs, and administerated acetaminophen(500 mg/kg, i.p.). After acetaminophen administeration, mice were sacrificed, and the liver was removed, rinsed with ice-cold $1.15{\%}$ KCI buffer, and homogenized at $4^{\circ}C$. Fractions(fraction Ⅰ, Ⅱ, Ⅲ) were isolated by differential centrifugation. Lipidperoxide, total SH, and glutathione(GSH) levels were measured in the Fraction Ⅰ. In addition, activities of hepatic enzyme, such as catalase, glutathione peroxidase(GSH-Px) were measured in the Fraction Ⅱ, and glutathione S-transferase(GST) was measured in the Fraction Ⅲ. Results : In vivo treatment of CHAS(BL18 and CV12) showed effective inhibition of acetaminophen induced lipid peroxidation, and showed elevations of total SH, GSH level, catalase, GSH-Px, GST activities. Conclusions : These results suggested that CHAS might suppress the formation of oxidative metabolites, and prevent acetaminophen induced hepatotoxicity.

• Herbal Formula Science
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• v.11 no.2
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• pp.135-146
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• 2003

Objectives : Wolguk-whan has been used as a prescription of natural drug for the treatment of stress digestive system disease. Recently, we reported that Wolguk-whan methnol extract (WGWM) exerted a significant protective effect against oxidative damage to the liver of ICR mice. This study was purposed to investigate the effects of Wolguk-whan water extract (WGWW) on liver injury induced by oxidative stress. Methods : In order to investigate the effects of WGWW on acute liver injury, ICR mice were pretreated with WGWW for 6days, starved for 24hrs, and administerated acetamirtophen(500mg/kg, i.p.). In the liver homogenates, lipid peroxide and glutathione(GSH) levels were measured. In addition, activities of hepatic enzyme, such as catalase, glutathione peroxidase(GSH-Px), glutathione S-transferase(GST) were measured in the hepatic mitochondrial and cytosolic fractions. Results : In vivo administeration of WGWW showed effective inhibition of acetaminophen induced lipid peroxidation, and showed elevations of GSH level, catalase, GSH-Px, GST activities. Conclusions : These results suggested that WGWW might suppress the formation of oxidative metabolites, and prevent acetaminophen induced hepatotoxicity.

• Toxicological Research
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• v.17
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• pp.299-304
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• 2001

Xenobiotics and their reactive intermediates bind to cellular macromolecules and/or generate oxidative stress. which provoke deleterious effects on the cell function. Induction of xenobiotic-biotrans-forming enzymes and antioxidant molecules is an important defense mechanism against such insults. A group of genes involved in the defense mechanism. e.g. genes encoding glutathione S-transferases. NAD(P)H: quinone oxidoreductase, UDP-glucuronosyltransferase (UDP-GT) and ${\gamma}$-glutamylcysteine synthetase (GGCS). have a common regulatory sequence, Antioxidant or Electrophile Responsive Element (ARE/EpRE). Recently. Nrf2. discovered as a homologue of erythroid transcription factor p45 NF-E2, was shown to bind ARE/EpRE and induce the expression of these defense genes. Mice that lack Nrf2 show low basal levels of expression and/or impaired induction of these genes. which makes the animals highly sensitive to xenobiotic toxicity. Indeed. we show here that nrf2-deficient mice had a higher mortality than did the wild-type mice when exposed to acetaminophen (APAP). Detailed analyses of APAP hepatotoxicity in the nrf2 knockout mice indicate that a large amount of reactive APAP metabolites was generated in the livers due to the impaired basal expression of two detoxifying enzyme genes, UDP-GT (Ugt1a6) and GGCS. while the cytochrome P450 content was unchanged. Thus. the studies using the nrf2 knockout mice clearly demonstrate significance of the expression of Nrf2-regulated enzymes in protection against xenobiotic toxicity.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.345-350
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• 2005

Acute toxicities of five pharmaceutical products were evaluated with aquatic microbes, invertebrates, and fish. The test pharmaceuticals, i.e., cimetidine, carbamazepine, diltiazem, acetaminophene, and metformin have been often detected in aquatic environment, but theire cological hazard on receptors of various trophic levels has seldom been evaluated. In the present study, we conducted acute toxicity assays with a marine bacterium, Vibrio fischeri, an invertebrate, Daphnia magna, and a fish, Japanese medake (Oryzias latipes). In general, D. magna, showed the most sensitive response to the test chemicals. Diltiazem exhibited the lowest EC50 value after 96 hr of exposure at 7.6 mg/L, followed by cimetidine >acetaminophen > metformin = carbamazepine in an order of decreasing susceptibility. With the fish, diltiazem and carbamazepine showed the 96 hr EC50 values at 14.1${\sim}$35.4 mg/L while acetaminophen, cimetidine, and metformin did not cause 50% mortality at 100 mg/L. Similar pattern was noted with the Microtox Assay, with which the median effective concentrations for acetaminophen, cimetidine, and metformin were found at the range between 301.8 and 755.4 mg/L. Carbamazepine and diltiazem exposure to the microbes resulted in EC50 values around 50 mg/L. Predicted no effect concentrations (PECs) of these pharmaceuticals derived from the EC5O values obtained from this study, and predicted environmental concentrations (PECs) obtained from available literatures were utilized to estimate ecological risks of the test compounds. No test pharmaceuticals resulted in risk quotients (PEC/PNEC) greater than 1, which suggests no serious potential ecological concerns. It should be noted however that further studies including the refinement of PEC derivation, identification and toxicity assessment of the metabolites and/or their interactions with other stressors may be warranted to better understand the environmental consequences of the residual pharmaceutical discharge to the waterway.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.2
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• pp.39-44
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• 2022

N-Acetylcysteine (NAC) is the standard antidote treatment for preventing hepatotoxicity caused by acetaminophen (AAP) poisoning. This review summarizes the recent evidence for the treatment of AAP poisoning. Several alternative intravenous regimens of NAC have been suggested to improve patient safety by reducing adverse drug reactions and medication errors. A two-bag NAC infusion regimen (200 mg/kg over 4 h, followed by 100 mg/kg over 16 h) is reported to have similar efficacy with significantly reduced adverse reactions compared to the traditional 3-bag regimen. Massive AAP poisoning due to high concentrations (more than 300-lines in the nomogram) needs to be managed with an increased maintenance dose of NAC. In addition to NAC, the combination therapy of hemodialysis and fomepizole is advocated for severe AAP poisoning cases. In the case of a patient presenting with an altered mental status, metabolic acidosis, elevated lactate, and an AAP concentration greater than 900 mg/L, hemodialysis is recommended even if NAC is used. Fomepizole decreases the generation of toxic metabolites by inhibiting CYP2E1 and may be considered an off-label use by experienced clinicians. Since the nomogram cannot be applied to sustained-release AAP formulations, all potentially toxic sustained-release AAP overdoses should receive a full course of NAC regimen. In case of ingesting less than the toxic dose, the AAP concentration is tested twice at an interval of 4 h or more; NAC should be administered if either value is above the 150-line of the nomogram.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.127-134
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• 2023

Pharmacokinetic (PK) data provide pivotal information in drug development, and they are usually first studied in the preclinical stage using various animals. However, quite often, animal PK data may not match with human PK, especially in metabolites. Thus, most regulatory agencies in the world make it mandatory to obtain metabolite information using ¹⁴C radiolabeled drug in human for small molecule drug candidates. However, such studies are expensive and time consuming and they are usually done at the end of Phase II trials using ~3.7 MBq of ¹⁴C labeled drug in a limited number of human subjects. Introduction of accelerator mass spectrometry (AMS) in this kind of study has revolutionized it. Since AMS can measure ¹⁴C level as close as natural abundance, it can quantify the amounts of ¹⁴C labeled drugs and their metabolites produced in human body that consumes less than the amount of 0.0037 MBq of ¹⁴C labeled drug, a very safe level of radioactive dose in human. Therefore, it is now possible to conduct human ¹⁴C studies safely in early clinical trials without spending hefty amount of money and time. Korea Radioisotope Center for Pharmaceuticals(KRICP) at Korea Institute of Biological and Medical Sciences(KIRAMS) has established an AMS facility in 2018, housing a 0.5MV AMS manufactured at the US National Electrostatics Corps (NEC). The AMS instrument has been validated using various standard samples that have been prepared at Lawrence Livermore National Laboratory in the US, a worldly reputable provider of AMS standards. In this paper, we present a mass balance study for acetaminophen in rats using AMS and prove that the study results are equivalent with those of literature, which shows the AMS facilities at KRICP has successfully installed and be ready to be used in the various PK studies using ¹⁴C labelled compounds for new drug development.

• Journal of Electrochemical Science and Technology
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• v.11 no.3
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• pp.310-317
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• 2020

A development of disposable strip-type galactose sensor for point-of-care testing (POCT) was studied, which was constructed using screen-printed carbon electrodes. Galactose levels were determined by the redox reaction of galactose oxidase in the presence of potassium ferricyanide as an electron transfer mediator in a small sample volume (i.e., less than 1 µL). The optimal performance of biosensor was systematically designated by varying applied potential, operating pH, mediator concentration, and amount of enzyme on the electrode. The sensor system was identified as a highly active for the galactose measurement in terms of the sensitivity (slope = 4.76 ± 0.05 nA/µM) with high sensor-to-sensor reproducibility, the linearity (R² = 0.9915 in galactose concentration range from 0 to 400 µM), and response time (t_95% = <17 s). A lower applied potential (i.e., 0.25 V vs. Ag/AgCl) allowed to minimize interference from readily oxidizable metabolites such as ascorbic acid, acetaminophen, uric acid, and acetoacetic acid. The proposed galactose sensor represents a promising system with advantage for use in POCT.