• BMB Reports
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• 제50권7호
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• pp.367-372
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• 2017

Monoacylglycerol acyltransferase 1 (MGAT) is a microsomal enzyme that catalyzes the synthesis of diacylglycerol (DAG) and triacylglycerol (TAG). However, the subcellular localization and catalytic function domain of this enzyme is poorly understood. In this report, we identified that murine MGAT1 localizes to the endoplasmic reticulum (ER) under normal conditions, whereas MGAT1 co-localize to the lipid droplets (LD) under conditions of enriching fatty acids, contributing to TAG synthesis and LD expansion. For the enzyme activity, both the N-terminal transmembrane domain and catalytic HPHG motif are required. We also show that the transmembrane domain of MGAT1 consists of two hydrophobic regions in the N-terminus, and the consensus sequence FLXLXXXn, a putative neutral lipid-binding domain, exists in the first transmembrane domain. Finally, MGAT1 interacts with DGAT2, which serves to synergistically increase the TAG biosynthesis and LD expansion, leading to enhancement of lipid accumulation in the liver and fat.

• 한국광학회지
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• 제14권3호
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• pp.327-330
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• 2003

본 논문에서는 도파로층이 1.3 $\mu\textrm{m}$ InGaAsP긴 파장 가변 BT(butt-coupled)-DBR(distributed bragg reflector)-LD(laser diode)를 제작하고, 특성을 측정하였다. Butt 결합 성장면의 성장조건을 건식식각과 선택식각 방법과 MOCVD(metal organic chemical vapor deposition)성장으로 최적화 한 후 활성층과 도파로층의 결합 효율을 측정한 결과 결합 효율이 85% 이상으로 나타났으며, 제작된 BT-DBR-LD에 연속전류를 인가 했을 때, 평균 임계전류는 약 21 ㎃, 최대 광출력이 25 ㎽ 이상으로 나타났다. 또한 위상제어 영역과 DBR영역에 각각 25㎃와 50 ㎃의 전류를 주입하여도 급격한 광출력 변화와 포화현상이 나타나지 않았다 이때 최대 파장 가변 폭은 7.4 nm, SMSR비는 40 ㏈이상으로 나타났다.

• 대한약침학회지
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• 제8권1호
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• pp.21-30
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• 2005

Objectives : To observe physiological anti-body effects of anti-BV, acute toxic response, measurement of $LD_{50}$, and the effects of anti-body were evaluated. Methods : $LD_{50}$ of Anti-Bee Venom were measured, and to analyze acute toxic responses, weight, and the anti-body effects various concentrations of Anti-BV were diluted and the survival rate was measured. Cell blood count (CBC), liver, spleen, and kidney pathologies were observed from the histological aspects. Results : Experiment was conducted to observe Anti-BV as the anti-body to the bee venom and the following results were obtained : 1.anti-BV was injected intraperitoneally and no toxic responses were witnessed. All of the experiment subjects stayed alive during the experiment, making $LD_{50}$ analysis impossible. 2.Anti-BV was injected intraperitoneally in mice and no significant weight changes were measured between the control group and the experiment groups. 3. Measuring the concentration dependent survival rate, the highest survival rate was at the concentration of $1.25{\times}10^2mg/kg$(1/2.000) for Anti-BV. 4. No particular results were shown in the CBC test. 5. Observation of changes in the organ tissues, Anti-BV was found to suppress blood stasis in the liver and inhibit necrosis of the cells. Conclusion : Above results suggest that Anti-BV doesn't cause any toxic responses in the body and works as an anti-body to the bee venom. Further studies must be followed to secure the findings.

• 한국식품영양학회지
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• 제11권1호
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• pp.77-81
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• 1998

치자에서 분리한 황색색소에 대한 랫드 및 토끼에 있어서의 단회투여 경구 독성시험을 수행하였다. 황색색소는 랫드의 경우 5,000, 2,500, 1,250, 625, 312,5 및 1mg/kg의 용량으로 경구로, 토끼에는 5,000, 2,500 및 1,250mg/kg의 용량으로 경구로 암.수 각각에 1회 투여한 후 14일 동안 관찰하였다. 시험결과에 있어 랫드 및 토끼의 모든 황색색소 투여군에서 사망예, 임상증상, 체중변화, 육안적 소견 및 병리조직학적 소견에서 특기할만한 이상은 관찰되지 않았으며 랫드와 토끼에서 황색색소의 LD50치를 산출할 수 없었다. 따라서 LD50치는 랫드 암.수 모두에서 체중 kg당 5,000mg 이상인 것으로 판단되었다. 이상의 결과로부터 치자로부터 분리한 황색색소는 랫드 및 토끼에서 단회 투여 경구 독성시험에서 어떠한 독성 및 부작용을 유발하지 않는 안전한 제제로 사료된다.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.470-477
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• 1995

Flavonoids from Scutellariae Radix possessed a dual function both as an anti-inflammatory agent and an enhancer of cellular activity in gingival fibroblast. The purpose of this study was to evaluate on the toxicity of ethanolic extract from the root of Scutellariae Radix Georgi and its flavonoids, Wogonin, Baicalein, and Baicalin were isolated and purified by the following method. The crude drug was extracted with ethyl acetate and the residue was dissolved in ethyl alcohol. The ethyl alcohol soluble fraction was separated, concentrated, and then chromatographed on a silica gel column. The acute oral LD 50 in rats was determined for EtOH ex. of Scutellariae Radix and three compounds were evaluated with a single oral gavage at three graded dosage levels. The acute intravenous LD 50 was determined with a single intravenous injection via the jugular vein at three graded dosage levels. Groups of 5 male and 5 female rats, 6 week of age at the start of the study, were fed diets containing 3 graded dosage levels for 14 days. Groups of 5 male and 5 female hamster received O.5ml of the test article at once in a day for 5 days to the buccal cheek pouch for two minutes each. The acute oral LD50 for EtOH ex. of Scutellariae Radix is 1430mg/kg, and for Wogonin 1320mg/kg, for Baicalein 1250mg/kg, for Baicalin 1330mg/kg. The acute intravenous toxicity of EtOH ex. of Scutellariae Radix and its extracts was found to be 27mg/kg body weight No toxic effects were observed in rats fed up to 200mg/kg of EtOH ex. of Scutellariae Radix, Wogonin, Baicalein and Baicalin in the diet for 14 days. The acute Mucouse Membrane LD 50 in hamsters was found to be greater than 100mg/kg. These results suggested that EtOH ex. of Scutellariae Radix and its flavonoids are safe for oral care products using limited amount of extract.

• 대한한의학방제학회지
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• 제13권1호
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• pp.123-143
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• 2005

Objective : This study was carried out to evaluate the liver toxicities of Wild Aconiti Tuber decoction. Methods : The amounts of aconitine in the methanol extract of Wild Aconiti Tuber was measured by HPLC. Safeties was studied by LD50 in mice. Liver toxicities were evaluated histologically and by CBC, blood chemistry after 2 weeks of 0.4g/kg/day clinical dosage oral administrations in rat. Results : 1. The amounts of aconitine in the methanol extract of Wild Aconiti Tuber is $1.697{\pm}0.052mg/g$. But aconitine was not detected in the water decoction of Wild Aconiti Tuber. 2. To evaluate LD50 and safeties of Wild Aconiti Tuber decoction, ICR mice were given high dose of 2, 5, 10g/kg for single time and were observed for 2 weeks. There were no dead animal and abnormal clinical sign and no abnormalities at the autopsy. So, LD50 was admitted to higher than 10g/kg. 3. After 2 weeks of 0.4g/kg/day clinical dosage oral administrations in rat, there was no significant change in the CBC and blood chemistry. 4. In the liver tissues of clinical dosage, mitotic figures, apoptosis and individual cell death were observed, but clear liver toxicities like fatty liver or necrosis were not observed. the liver tissues of high dose in mice, hydropic changes were getting severe as dose grows. Conclusions : According to the results, though aconitine was not detected in the Wild Aconiti Tuber decoction, 0.4g/kg/day 2 weeks p. o (clinical dosage) group showed weak changes in the liver tissues and high dose group showed liver toxicities like hydropic changes.

• 한국동물위생학회지
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• 제15권1호
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• pp.58-66
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• 1992

The insecticide p-nitropheny diethyl thiophospate is alse known by the symbol E.605 and a legion of trade names including “parathion”. The insecticide is widely used in agriculture, but it is highly toxic and now clear that parathion behaves like a cholinergic drug by inhibiting the enzyme cholinesterase. In order to know acute toxicity and the changes of glucose concentrations and activity according to time lapsed in female mice given orally single with the half dose to $LD_{50}$ of parathion, glucose contents and cholinesterase activities in serum as well as cholinesterase activities in whole brain and spinal cord were investigated, otherwise median lethal dose ($LD_{50}$) of parathion given orally against female mice was determined. The results obtained were summerized as follows ; 1. $LD_{50}$ value of parathion given orally to female mice was 7.1mg/kg(95% confidence limits, 3.8-13.1mg/kg) 2. The inhibition rate of cholinesterase activities in serum of parathion-administrated mice according to time lapsed were peakly decreased to 61% after 30 minutes in comparison to control group, but activities were completely recovered after 48 hours. 3. The inhibition rate of cholinesterase activities in whole brain of parathion-administrated mice according to time lapsed were peakly decreased to 49% after 2 hours in completely recovered after 24 hours. 4. The inhibition rate of cholinesterase activities in spinal cord of parathion-administrated mice according to time lapsed were peakly decreased to 57% after 2 hours in comparison to control group, but activities were completely recovered after 48 hours. 5. The changes of glucose contents in serum of parathion-administrated mice according to time lapsed and in directly after death due to parathion poisoning were no significantly difference.

• 한국산업보건학회지
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• 제25권1호
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• pp.58-71
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• 2015

Objectives: The aims of this study were to investigate the classification system of chemical substances in the Occupational Safety and Health Act(OSHA) and Chemical Substances Control Act(CSCA) and to compare several health indices (i.e., Time Weighted Average (TWA), Lethal Dose ($LD_{50}$), and Lethal Concentration ($LC_{50}$) of chemical substances by categories in each law. Methods: The chemicals regulated by each law were classified by the specific categories provided in the respective law; seven categories for OSHA (chemicals with OELs, chemicals prohibited from manufacturing, etc., chemicals requiring approval, chemicals kept below permissible limits, chemicals requiring workplace monitoring, chemicals requiring special management, and chemicals requiring special heath diagnosis) and five categories from the CSCA(poisonous substances, permitted substances, restricted substances, prohibited substances, and substances requiring preparation for accidents). Information on physicochemical properties, health indices including CMR characteristics, $LD_{50}$ and $LD_{50}$ were searched from the homepages of the Korean Occupational and Safety Agency and the National Institute of Environmental Research, etc. Statistical analysis was conducted for comparison between TWA and health index for each category. Results: The number of chemicals based on CAS numbers was different from the numbers of series of chemicals listed in each law because of repeat listings due to different names (e.g., glycol monoethylether vs. 2-ethoxy ethanol) and grouping of different chemicals under the same serial number(i.e., five different benzidine-related chemicals were categorized under one serial number(06-4-13) as prohibited substances under the CSCA). A total of 722 chemicals and 995 chemicals were listed at the OSHA and its sub-regulations and CSCA and its sub-regulations, respectively. Among these, 36.8% based on OSHA chemicals and 26.7% based on CSCA chemicals were regulated simultaneously through both laws. The correlation coefficients between TWA and $LC_{50}$ and between TWA and $LD_{50}$, were 0.641 and 0.506, respectively. The geometric mean values of TWA calculated by each category in both laws have no tendency according to category. The patterns of cumulative graph for TWA, $LD_{50}$, $LC_{50}$ were similar to the chemicals regulated by OHSA and CCSA, but their median values were lower for CCSA regulated chemicals than OSHA regulated chemicals. The GM of carcinogenic chemicals under the OSHA was significantly lower than non-CMR chemicals($2.21mg/m^3$ vs $5.69mg/m^3$, p=0.006), while there was no significant difference in CSCA chemicals($0.85mg/m^3$ vs $1.04mg/m^3$, p=0.448). $LC_{50}$ showed no significant difference between carcinogens, mutagens, reproductive toxic chemicals and non-CMR chemicals in both laws' regulated chemicals, while there was a difference between carcinogens and non-CMR chemicals in $LD_{50}$ of the CSCA. Conclusions: This study found that there was no specific tendency or significant difference in health indicessuch TWA, $LD_{50}$ and $LC_{50}$ in subcategories of chemicals as classified by the Ministry of Labor and Employment and the Ministry of Environment. Considering the background and the purpose of each law, collaboration for harmonization in chemical categorizing and regulation is necessary.

• 농약과학회지
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• 제5권4호
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• pp.57-61
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• 2001

영농에서 노동력 절감을 위해 $2{\sim}3종$ 농약을 혼용하여 살포하는 것은 흔한 농약살포 방법이다. 과수 재배시 널리 사용되고있는 4종 살충제의 상호혼합 및 혼용이 인체에 미치는 영향을 구명하고 안전성을 확보할 목적으로 급성독성시험, 유기인계 및 카바메이트계 농약의 주 저해효소인 콜린에스테라제의 활성에 미치는 영향을 평가하였다. 포스팜액제, 디디브이피 유제, 피레스 유제 및 푸라치오카브 유제의 단제 및 혼합제에 대한 급성독성 및 콜린에스트라제의 활성에 미치는 영향을 시험한 결과 포스팜 액제 및 디디브이피 유제의 급성경구독성 $LD_{50}$은 랫드에서 각각 30 mg/kg, 93 mg/kg로 고독성이었으며 나머지는 보통독성이었다. 혼합에 의한 급성경구 및 경피독성 시험결과, $LD_{50}$이 이론치보다 $0.29{\sim}1.0$ 배정도 낮은 상승독성이 발현되었다. 혼용에 의한 급성경구독성 시험결과 포스팜+디디브이피 조합의 경우, $LD_{50}$이 16 mg/kg로 맹독성 농약으로 구분되었으며, 그 외의 조합은 모두 고독성 농약으로 구분되었다. 급성경피독성시험의 경우도 경구와 동일한 결과로 독성발현이 전체적으로 상승되었다. 농약의 혼합에 의한 혈장내 cholinesterase 의 $ID_{50}$의 변화는 약제처리 30분에는 이론치보다 현저한 효소억제가 인정되었으나, 60분에는 이론치와 큰 차이가 없었다.

• 대한예방한의학회지
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• 제17권3호
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• pp.19-30
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• 2013

This study was aimed to develop a new formula for herbal medicine-safety classification in terms of evidence-based medicine. Recently, human equivalent dose(HED)-based therapeutic index was developed for herbal medicine-safety classification by transforming $LD_{50}$ to HED. However, the use of the $ED_{50}$ and $LD_{50}$ to derive the therapeutic index may be misleading as to safety, depending on the slope of the dose-response curves for therapeutic and lethal effects. To overcome this deficiency, HED-based MOS(Margin of Safety)was developed and suggested in this study. The HED-based MOS developed by using $LD_1$, changing to ALD(approximate lethal dose), and $ED_{99}$. The HED-based MOS seems to be more useful and safer than HED-based therapeutic index since its values for several herbal medicines are basically two times less than the values from HED-based therapeutic index. Thus, HED-based MOS can be a good example of Evidence-based approach for herbal medicine-safety classification.