Cheongwon, South Korea
Cheongwon, South Korea

Time filter

Source Type

Qian Y.R.,Yanbian University | Lee M.-J.,Chonnam National University | Lee M.-J.,Biotoxtech Co. | Hwang S.,Chonnam National University | And 3 more authors.
Korean Journal of Physiology and Pharmacology | Year: 2010

Valproic acid (VPA) is a well-known anti-epileptic and mood stabilizing drug. A growing number of reports demonstrate that VPA is neuroprotective against various insults. Despite intensive efforts to develop new therapeutics for stroke over the past two decades, all treatments have thus far failed to show clinical effect because of treatment-limiting side effects of the drugs. Therefore, a safety-validated drug like VPA would be an attractive candidate if it has neuroprotective effects against ischemic insults. The present study was undertaken to examine whether pre- and post-insult treatments with VPA protect against brain infarct and neurological deficits in mouse transient (tMCAO) and permanent middle cerebral artery occlusion (pMCAO) models. In the tMCAO (2 hr MCAO and 22 hr reperfusion) model, intraperitoneal injection of VPA (300 mg/kg, i.p.) 30 min prior to MCAO significantly reduced the infarct size and the neurological deficit. VPA treatment immediately after reperfusion significantly reduced the infarct size. The administration of VPA at 4 hr after reperfusion failed to reduce the infarct size and the neurological deficit. In the pMCAO model, treatment with VPA (300 mg/kg, i.p.) 30 min prior to MCAO significantly attenuated the infarct size, but did not affect the neurological deficit. Western blot analysis of acetylated H3 and H4 protein levels in extracts from the ischemic cortical area showed that treatment with VPA increased the expression of acetylated H3 and H4 at 2 hrs after MCAO. These results demonstrated that treatment with VPA prior to ischemia attenuated ischemic brain damage in both mice tMCAO and pMCAO models and treatment with VPA immediately after reperfusion reduced the infarct area in the tMCAO model. VPA could therefore be evaluated for clinical use in stroke patients.

PubMed | Catholic University of Daegu, Food Republic, Amore Pacific, Dongguk University and 6 more.
Type: | Journal: Regulatory toxicology and pharmacology : RTP | Year: 2016

Local lymph node assay: 5-bromo-2-deoxyuridine-flow cytometry method (LLNA: BrdU-FCM) is a modified non-radioisotopic technique with the additional advantages of accommodating multiple endpoints with the introduction of FCM, and refinement and reduction of animal use by using a sophisticated prescreening scheme. Reliability and accuracy of the LLNA: BrdU-FCM was determined according to OECD Test Guideline (TG) No. 429 (Skin Sensitization: Local Lymph Node Assay) performance standards (PS), with the participation of four laboratories. Transferability was demonstrated through successfully producing stimulation index (SI) values for 25% hexyl cinnamic aldehyde (HCA) consistently greater than 3, a predetermined threshold, by all participating laboratories. Within- and between-laboratory reproducibility was shown using HCA and 2,4-dinitrochlorobenzene, in which EC2.7 values (the estimated concentrations eliciting an SI of 2.7, the threshold for LLNA: BrdU-FCM) fell consistently within the acceptance ranges, 0.025-0.1% and 5-20%, respectively. Predictive capacity was tested using the final protocol version 1.3 for the 18 reference chemicals listed in OECD TG 429, of which results showed 84.6% sensitivity, 100% specificity, and 88.9% accuracy compared with the original LLNA. The data presented are considered to meet the performance criteria for the PS, and its predictive capacity was also sufficiently validated.

PubMed | Korea Testing & Research Institute, Amore Pacific, Biotoxtech Co., Chung - Ang University and 3 more.
Type: | Journal: Toxicology in vitro : an international journal published in association with BIBRA | Year: 2016

Here, we report the results of a prevalidation trial for an in vitro eye irritation test (EIT) using the reconstructed human cornea-like epithelium, MCTT HCE. The optimal cutoff to determine irritation in the prediction model was established at 35% with the receiver operation characteristics(ROC) curve for 126 substances. Within-lab(WL) and between-lab(BL) reproducibility was tested for 20 reference substances by 3 participating laboratories. Viability data described by meanSD or 1/2 difference between duplicate wells, and scatter plots, demonstrated the WL/BL consistency. WL/BL concordance with the binary decision, whether non-irritant or irritant was estimated to be 85-95% and 95%, respectively. WL/BL reproducibility of viability data was further supported by a strong correlation(ICC, r>0.9). WL/BL agreement of binary decisions was also examined by Fleiss Kappa statistics, which showed a strong level of agreement (>0.78), nevertheless weaker than the reproducibility of the viability. The EIT with MCTT HCE exhibited a sensitivity of 82.2% (60/73), a specificity of 81.1% (43/53), and an accuracy of 81.8% (103/126) for 126 reference substances (for liquids; a sensitivity of 100% (47/47), a specificity of 70.6% (24/34), and an accuracy of 87.7% (71/81), and for solids, a sensitivity of 50% (13/26), a specificity of 100% (19/19), and an accuracy of 71.1% (32/45), suggesting that the accuracy is satisfactory but the sensitivity needs improvement, which shall be addressed through correcting the poor sensitivity for solid substances in future full validation trials.

PubMed | Ewha Womans University, Biotoxtech Co., Amore Pacific and Catholic University of Daegu
Type: Comparative Study | Journal: Toxicology letters | Year: 2015

Mouse local lymph node assay (LLNA, OECD TG429) is an alternative test replacing conventional guinea pig tests (OECD TG406) for the skin sensitization test but the use of a radioisotopic agent, (3)H-thymidine, deters its active dissemination. New non-radioisotopic LLNA, LLNA:BrdU-FCM employs a non-radioisotopic analog, 5-bromo-2-deoxyuridine (BrdU) and flow cytometry. For an analogous method, OECD TG429 performance standard (PS) advises that two reference compounds be tested repeatedly and ECt(threshold) values obtained must fall within acceptable ranges to prove within- and between-laboratory reproducibility. However, this criteria is somewhat arbitrary and sample size of ECt is less than 5, raising concerns about insufficient reliability. Here, we explored various statistical methods to evaluate the reproducibility of LLNA:BrdU-FCM with stimulation index (SI), the raw data for ECt calculation, produced from 3 laboratories. Descriptive statistics along with graphical representation of SI was presented. For inferential statistics, parametric and non-parametric methods were applied to test the reproducibility of SI of a concurrent positive control and the robustness of results were investigated. Descriptive statistics and graphical representation of SI alone could illustrate the within- and between-laboratory reproducibility. Inferential statistics employing parametric and nonparametric methods drew similar conclusion. While all labs passed within- and between-laboratory reproducibility criteria given by OECD TG429 PS based on ECt values, statistical evaluation based on SI values showed that only two labs succeeded in achieving within-laboratory reproducibility. For those two labs that satisfied the within-lab reproducibility, between-laboratory reproducibility could be also attained based on inferential as well as descriptive statistics.

PubMed | Ewha Womans University, Biotoxtech Co. and Food Republic
Type: | Journal: Regulatory toxicology and pharmacology : RTP | Year: 2016

The local lymph node assay using 5-bromo-2-deoxyuridine (BrdU) with flow cytometry (LLNA: BrdU-FCM) is a modified LLNA that is used to identify skin sensitizers by counting BrdU-incorporated lymph node cells (LNCs) with flow cytometry. Unlike other LLNA methods (OECD TG 429, 442A and 442B) in which the CBA/J mouse strain is used, LLNA: BrdU-FCM was originally designed to be compatible with BALB/c, a mouse strain that is more widely used in many countries. To justify the substitution of CBA/J for BALB/c, the equivalence of the test results between two strains shall be established prior to the official implementation of LLNA: BrdU-FCM. This study aims to compare the test results of LLNA: BrdU-FCM produced in BALB/c mice with those in CBA/J mice for 18 reference substances, including 13 sensitizers and 5 non-sensitizers, listed in OECD Test Guideline 429. Based on the LLNA: BrdU-FCM test procedure, we selected an appropriate solvent and then performed preliminary tests to determine the non-irritating dose ranges for the main study, which revealed the difference in the irritation responses to 8 of the 18 chemicals between the two strains. In the main study, we measured the changes in the number of total LNCs, which indicated differences in the responses to test chemicals between the two strains. However, the stimulation index obtained with the counts of BrdU-incorporated LNCs with 7-AAD using flow cytometry yielded comparable results and 100% concordance between the BALB/c and CBA/J mouse strains was achieved, suggesting that the performance of LLNA: BrdU-FCM using BALB/c mice was equivalent to that with CBA/J mice.

PubMed | Korea University, University of Ulsan, Namseoul University, Chungbuk National University and 2 more.
Type: | Journal: Journal of ethnopharmacology | Year: 2016

Acorus gramineus rhizoma (AGR) is the dry rhizome of Acorus gramineus Solander from the family Araceae that has been used as sedative, analgesic, diuretic, digestive and antifungal agent.To evaluate the no-observed-adverse-effect level (NOAEL) and the toxicity of AGR, following repeated oral administration to rats for 13 weeks.AGR was administered by oral gavage to groups of rats (10 per group, each sex) at doses of 0 (control), 25, 74, 222, 667, or 2,000mg/kg/day, 5 times per week for 13 weeks. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology, sperm motility, sperm morphology, organ weights, gross and histopathological findings were compared between control and AGR groups.No mortality or remarkable clinical signs were observed during this 13-week study. No adverse effects on body weight, food consumption, urinalysis, hematology, serum chemistry, organ weights, gross lesion, histopathology, vaginal cytology, sperm motility or deformity were observed in any of the male or female rats treated with AGR.On the basis of these results, the NOAEL of AGR is determined to be 2,000mg/kg/day for male and female rats.

PubMed | Biotoxtech Co., University of Ulsan, Nippon Hypox Laboratories Inc. and Chungbuk National University
Type: | Journal: Drug design, development and therapy | Year: 2015

HX-1171 (1-O-hexyl-2,3,5-trimethylhydroquinone) is a promising antioxidant with therapeutic potential for hepatic fibrosis. The aim of this study was to investigate the tolerability and pharmacokinetics of HX-1171 in healthy volunteers.A randomized, single-blind, placebo-controlled, dose escalation study was conducted in 83 subjects. In the single ascending dose study, 20, 40, 80, 160, 300, 600, 1,200, 1,500 or 2,000 mg of HX-1171 was administered to 67 subjects. In the multiple ascending dose study, 500 or 1,000 mg was administered to 16 subjects for 14 days. The plasma and urine concentrations of HX-1171 were determined by using a validated liquid chromatography-mass spectrometry method. Pharmacokinetic parameters were obtained by non-compartmental analysis. Tolerability was assessed based on physical examinations, vital signs, clinical laboratory tests, and electrocardiograms.Adverse events reported in the study were all mild in intensity and resolved without any sequelae. HX-1171 was rapidly and minimally absorbed with a median time at maximal concentration of 0.63-1.50 hours and slowly eliminated with a terminal half-life of 21.12-40.96 hours. Accumulation index ranged from 2.0 to 2.2 after repeated dosing for 14 days. For both the single and multiple doses administrations, urinary concentrations indicated that less than 0.01% of the HX-1171 administered was excreted in urine.HX-1171 was well tolerated and minimally absorbed in healthy volunteers. The pharmacokinetic profile of HX-1171 was consistent with once-a-day dosing.

PubMed | National Health Research Institute, Biotoxtech Co. and Chungbuk National University
Type: Journal Article | Journal: Toxicological research | Year: 2016

This study aimed to evaluate the potential toxicity and safety of ethyl hydrogen adipate (EHA) by determining its effect on the reproductive function and development of Sprague-Dawley (SD) rats at dose levels of 0 (control), 200, 400, and 800 mg/kg/day. One male and five females of the 800 mg/kg/day died. Body weight loss was observed in the males of the 800 mg/kg/day and in females of the 400 and 800 mg/kg/day. In addition, mating indices decreased and pre-implantation loss rates increased in parental animals of the 400 and 800 mg/kg/day. The gestation index decreased in the male and female rats of the 800 mg/kg/day. Moreover, the body weight of the pups from the 800 mg/kg/day group decreased on post-parturition day 4. These results indicated that the no-observed-adverse-effect level of EHA for parental males and females was 400 mg/kg/day and 200 mg/kg/day, respectively, and that for pups was 400 mg/kg/day.

PubMed | Biotoxtech Co., Chungbuk National University and Pusan National University
Type: Journal Article | Journal: Toxicological research | Year: 2016

Lithospermum erythrorhizon has long been used as a traditional oriental medicine. In this study, the acute and 28-day subacute oral dose toxicity studies of hexane extracts of the roots of L. erythrorhizon (LEH) were performed in Sprague-Dawley rats. In the acute toxicity study, LEH was administered once orally to 5 male and 5 female rats at dose levels of 500, 1,000, and 2,000 mg/kg. Mortality, clinical signs, and body weight changes were monitored for 14 days. Salivation, soft stool, soiled perineal region, compound-colored stool, chromaturia and a decrease in body weight were observed in the extract-treated groups, and no deaths occurred during the study. Therefore, the approximate lethal dose (ALD) of LEH in male and female rats was higher than 2,000 mg/kg. In the subacute toxicity study, LEH was administered orally to male and female rats for 28 days at dose levels of 25, 100, and 400 mg/kg/day. There was no LEH-related toxic effect in the body weight, food consumption, ophthalmology, hematology, clinical chemistry and organ weights. Compound-colored (black) stool, chromaturia and increased protein, ketone bodies, bilirubin and occult blood in urine were observed in the male and female rats treated with the test substance. In addition, the necropsy revealed dark red discoloration of the kidneys, and the histopathological examination showed presence of red brown pigment or increased hyaline droplets in the renal tubules of the renal cortex. However, there were no test substance-related toxic effects in the hematology and clinical chemistry, and no morphological changes were observed in the histopathological examination of the kidneys. Therefore, it was determined that there was no significant toxicity because the changes observed were caused by the intrinsic color of the test substance. These results suggest that the no-observed-adverse-effect Level (NOAEL) of LEH is greater than 400 mg/kg/day in both sexes.

PubMed | Biotoxtech Co., Chungbuk National University and Pusan National University
Type: Journal Article | Journal: Toxicological research | Year: 2015

Lithospermum erythrorhizon has long been used in traditional Asian medicine for the treatment of diseases, including skin cancer. The oral toxicity of a hexane extract of Lithospermum erythrorhizon root (LEH) was investigated in Beagle dogs by using single escalating doses, two-week dose range-finding, and 4-week oral repeat dosing. In the single dose-escalating oral toxicity study, no animal died, showed adverse clinical signs, or changes in body weight gain at LEH doses of up to 2,000 mg/kg. In a 2 week dose range-finding study, no treatment-related adverse effects were detected by urinalysis, hematology, blood biochemistry, organ weights, or gross and histopathological examinations at doses of up to 500 mg LEH/kg/day. In the 4 week repeat-dose toxicity study, a weight loss or decreased weight gain was observed at 300 mg/kg/day. Although levels of serum triglyceride and total bilirubin were increased in a dose dependent manner, there were no related morphological changes. Based on these findings, the sub-acute no observable adverse effect level for 4-week oral administration of LEH in Beagles was 100 mg/kg/day.

Loading Biotoxtech Co. collaborators
Loading Biotoxtech Co. collaborators