A Comparison on Bereavement Support Stress and Coping the Stress between Nurses in the Cancer Unit and Nurses in the General Unit

Hyang-Yeon Lee,Youn-Ok Lee,Eun-Young Choi 한국간호과학회 2005 한국간호과학회 학술대회 Vol.2005 No.10

Antidepressant drug paroxetine blocks the open pore of Kv3.1 potassium channel

Lee, Hyang Mi,Chai, Ok Hee,Hahn, Sang June,Choi, Bok Hee The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.1

In patients with epilepsy, depression is a common comorbidity but difficult to be treated because many antidepressants cause pro-convulsive effects. Thus, it is important to identify the risk of seizures associated with antidepressants. To determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to high-frequency firing of interneurons, using the whole-cell patch-clamp technique. Kv3.1 channels were cloned from rat neurons and expressed in Chinese hamster ovary cells. Paroxetine reversibly reduced the amplitude of Kv3.1 current, with an $IC_{50}$ value of $9.43{\mu}M$ and a Hill coefficient of 1.43, and also accelerated the decay of Kv3.1 current. The paroxetine-induced inhibition of Kv3.1 channels was voltage-dependent even when the channels were fully open. The binding ($k_{+1}$) and unbinding ($k_{-1}$) rate constants for the paroxetine effect were $4.5{\mu}M^{-1}s^{-1}$ and $35.8s^{-1}$, respectively, yielding a calculated $K_D$ value of $7.9{\mu}M$. The analyses of Kv3.1 tail current indicated that paroxetine did not affect ion selectivity and slowed its deactivation time course, resulting in a tail crossover phenomenon. Paroxetine inhibited Kv3.1 channels in a use-dependent manner. Taken together, these results suggest that paroxetine blocks the open state of Kv3.1 channels. Given the role of Kv3.1 in fast spiking of interneurons, our data imply that the blockade of Kv3.1 by paroxetine might elevate epileptic activity of neural networks by interfering with repetitive firing of inhibitory neurons.

Quality Characteristics of Skate Sashimi Fermented by Pine Needles

Hyang-Gyeong Lee,Dong-Ok Chung,Sang-Ok Bae 한국식품영양과학회 2015 한국식품영양과학회 학술대회발표집 Vol.2015 No.8

P-Glycoprotein Inhibitory Activity of Indonesian Medicinal Plants in Human Breast Cancer Cells

Hyang Rim Kim,Soo Yeon Chung,Yeon-Hee Jeong,Eun Jung Go,한아름,Na Hyung Kim,Min KyungSung,Gina Song,Jung Ok Jang,남주원,Hwa Jeong Lee,서은경 한국생약학회 2004 Natural Product Sciences Vol.10 No.6

In order to examine their effects on the P-glycoprotein (P-gp) activity in human breast cancer cels,Calotropis gigantea, Curcuma aeruginosa, Merremia mammosa, Sindora sumatrana, and Zingiber casumunar,showed the most potent P-gp inhibitory activity. When each of these extracts was treated together with theanticancer agent, daunomycin, they increased the cytotoxic activity of daunomycin up to IC50 values of les than6.62 M, which is a value with a positive control, verapamil. Also, other 15 plant extracts exhibited significant P-50 values betwen 6.62 and 13.20 M. These prospective samples wil be subjectedto further laboratory phytochemical investigation to find active principles.Keywords . . . . . . .

Cooperative Activity of Subunits of Human Ferritin Heteropolymers in Escherichia coli

Lee, Jung,Seo, Hyang-Yun,Jeon, Eun-Soon,Park, Ok-Soon,Lee, Kang-Min,Park, Chung-Ung,Kim, Kyung-Suk Korean Society for Biochemistry and Molecular Biol 2001 Journal of biochemistry and molecular biology Vol.34 No.4

We constructed a comparative expression system in order to produce recombinant human ferritin homo- and heteropolymers in Escherichia coli. Human ferritin H-(hfH) and L-chain (hfL) genes were expressed without amino acid changes under the control of a tac promoter. Ferritin heteropolymers of varying subunit composition were also produced by combining two different expression systems, a bicistronic expression system and a coplasmid expression system. As a result, recombinant H-chain ferritin and ferritin heteropolymers were catalytically active in forming iron core in vivo. In particular, the ferritin heteropolymer that is composed of 7% H-subunit and 93% L-subunit was capable of forming an iron core of the protein, while the L-chain ferritin homopolymer was inactive in vivo. This result indicates that the two H-subunits (i.e., 7% H-subunit content) are important to keep ferritin active in the cells. In addition, human ferritins were identified as the major iron binding proteins in the transformed cells. Also, the amount of iron bound to the recombinant ferritins was proportional to the H-subunit content in ferritin heteropolymers in vivo.

Rheological anomalies of the poly(ethylene 2, 6-naphthalate) and poly(ethylene terephthalate) blends depending on the compositions

Lee, Hyang-Mok,Suh, Duck-Jong,Kil, Seung-Bum,Park, O-Ok,Yoon, Kwan-Han The Korean Society of Rheology 1999 Korea-Australia rheology journal Vol.11 No.3

The effects of the transreactions on the rheological properties have been found in the poly(ethylene 2, 6-naphthalate) (PEN) and poly (ethylene terephthalate) (PET) blends. The rheological properties were very much dependent on the blend compositions, which, in turn, were related to extent of the reactions. In particular, a blend with 50/50 wt% composition exhibits an unusual and remarkable decrease in complex viscosity and it may be related to the randomness of the copolymer structure through transreactions. It has been identified by investigating the extent of transreactions and block length of the copolymer from the (ethylene 2, 6-naphthalate) (EN) and (ethylene terephthalate) (ET) units from $^1{H}$ n.m.r. spectra.

Occurrence and simultaneous determination of nivalenol and deoxynivalenol in rice and bran by HPLC-UV detection and immunoaffinity cleanup

Ok, Hyun Ee,Lee, Sang Yoo,Chun, Hyang Sook Elsevier 2018 Food control Vol.87 No.-

<P><B>Abstract</B></P> <P>A simple and accurate method for simultaneously quantifying two co-occurring <I>Fusarium</I> mycotoxins in rice and bran, nivalenol (NIV) and deoxynivalenol (DON), is described. The method involves the use of an immunoaffinity column for cleanup and HPLC-UV detection for quantification. The limits of quantification were <11.09 μg kg<SUP>−1</SUP> for the two toxins in rice and bran. The mean recoveries from blank samples spiked at levels of 100–1000 μg kg<SUP>−1</SUP> were 86.2–106.6% for NIV and 93.1–106.2% for DON, with relative standard deviations of 6–15% for NIV and 3–11% for DON, respectively. The detection rate of NIV in 482 rice and 239 bran samples was 34–96%, where the level ranging from 5.7 to 2791.4 μg kg<SUP>−1</SUP>, whereas that for DON was 10.4–44.8% with levels ranging from 7.1 to 655.6 μg kg<SUP>−1</SUP>. The co-occurrence rates of NIV and DON were 9.1%, 14.9%, and 41.5% for white rice, brown rice, and bran, respectively. The estimated dietary intakes of NIV and DON for the Korean population based on the occurrence data were well below the established tolerable daily intake.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simple simultaneous analysis of nivalenol and deoxynivalenol in rice and bran. </LI> <LI> This method based on immunoaffinity cleanup and HPLC-UV detection. </LI> <LI> Performance criteria and measurement uncertainty were within the acceptable range. </LI> <LI> Co-occurrence rates of two toxins in 482 rice and 239 bran samples were 9.1–41.5%. </LI> <LI> Dietary intakes of two toxins for the Korean were well below the established TDI. </LI> </UL> </P>

A Comparison of Diclofenac versus Dexamethasone for the Treatment of Postcataract Inflammation

Lee, Suk Hyang,Suh, Ok Kyung,Jung, Hyun Ah,An, Gi Jung Korean College Of Clinical Pharmacy 2000 한국임상약학회지 Vol.10 No.1

백내장 수술 추 염증치료를 위해 일반적으로 부작용이 많은 국소 점안 스테로이드를 사용해왔다. 최근 NSAID계열의 점안액이 항염증 치료약물로 개발되면서 선택적인 약물치료가 가능하게 되었으나 단일치료약물로 사용하는 경우는 드물다. 본 연구는 NSAID계 diclofenac 점안액의 백내장 수술 후 염증치료 효과를 스테로이드체 dexamethasone 점안액과 비교하여 단일 치료약물로서 사용할 수 있는 지 연구하고자하였다. 백내장 수술을 받은 환자로서 안압이 22 mmHg 이상 당뇨환자, 수술대상 눈에 이미 질환 및 수술 경력이 있는 자를 제외하였다. 백내장 수술 후 항염종 약물로서 diclofenac 또는 dexamethasone을 28일 동안 투여하고 항염증효과의 평가를 위하여 세극등 검사로저 전방내 염증세포와 결막, 각막등의 전안부 관찰을 수술 전, 수술 후 1, 3, 7, 14, 28일에 시행하였고, 시력검사는 수술 추 7, 28일에 시행하였다. 안전성의 평가는 안압검사와 세극등 검사상 관찰된 이상소견으로 평가하였다. 총 73명의 연구대상 중 dexameasone군은 41명, diclofenac군은 32명이며 두 군간에 나이, 백내장의 심한 정도, 안구질환 등에 있어 유의한 차이가 없었다 전방내 항염증세포수의 감소에서 두 군간에 유의할 만한 차이가 없었고, 수술 후 최대 교정 시력에서도 동일한 효과를 보였다. 안전성에서 안압의 상승이 두군간에 통계적인 유의한 차이를 보이지 않았으나 dexamethasone군에서 1명의 환자가 45 mmHg 이상 증가하여 약물치료가 필요하였으나 diclofenac군에서는 안압이 상승한 환자가 없었다. 결론적으로 효능 및 안전성에서 두 약물간에 통제적, 임상적으로 유의한 차이가 없었으며 diclofenac 점안액은 백내장 수술 후 항염증치료제로서 충분한 효과가 있으며 안압상승, 감염 등 부작용이 우려되는 dexamethasone점안액의 대체약물로 사용될 수 있을 것으로 평가된다.

Rheological properties of polyvinylsiloxane impression materials before mixingand during setting related to handling characteristics

Hyang-Ok Lee,이인복 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The purpose of this study is to determine and compare the handling and rheological properties of poly\-vinylsiloxane impression pastes before mixing and during setting, and to investigate the effect of its con\-stituents on the properties of the materials. Five polyvinylsiloxane impression materials (Examixfine, Extrude, Honigum, Imprint II, and Express) were used. A flow test and a drip test were performed to deter\-mine the handling characteristics. The rheological properties of each impression material prior to mixing (shear stress, viscosity) and during setting (storage modulus G', loss modulus G'', loss tangent tand) were measured with a stress-controlled rheometer at 25oC and 32oC, respectively. Inorganic filler content of each impression material was measured and observed with a SEM. The molecular weight distribution of polymer matrix was determined with a gel permeation chromatography (GPC). Express and Honigum display lower flow compared to the other materials, due to their high yield-stress values. Examixfine exhibits the greatest flow. All materials display pseudoplastic behavior, excluding the Examixfine catalyst. The viscosities at low shear rate are greatest for Express and Honigum; however, under high shear conditions, the viscosities of Extrude and Honigum are the lowest. Following mixing, each material show an increase in G', finally reach\-ing a plateau, and the tand rapidly decreases with time. Imprint II shows the highest final G' as well as the most rapid decrease in tand. Express and Imprint II present the highest filler content and rough filler surface, while Honigum shows the lowest filler content and small filler particles. Most products are composed of polymers over 30kDa and oligomers less than 1kDa. Each impression material possesses different rheo\-logical properties, which significantly affect the handling characteristics. The yield stress of the impression material minimizes unnecessary flow prior to and after seating. Viscoelastic change during setting of each impression material determines the setting time and the stiffness after setting. These rheological properties of impression materials are affected by the filler content and molecular weight distribution of polymer matrix.

Rheological properties of polyvinylsiloxane impression materials before mixing and during setting related to handling characteristics

Lee, Hyang-Ok,Lee, In-Bog 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

The purpose of this study is to determine and compare the handling and rheological properties of polyvinylsiloxane impression pastes before mixing and during setting, and to investigate the effect of its constituents on the properties of the materials. Five polyvinylsiloxane impression materials (Examixfine, Extrude, Honigum, Imprint II, and Express) were used. A flow test and a drip test were performed to determine the handling characteristics. The rheological properties of each impression material prior to mixing (shear stress, viscosity) and during setting (storage modulus G', loss modulus G", loss tangent $tan{\delta}$) were measured with a stress-controlled rheometer at $25^{\circ}C$ and $32^{\circ}C$, respectively. Inorganic filler content of each impression material was measured and observed with a SEM. The molecular weight distribution of polymer matrix was determined with a gel permeation chromatography (GPC). Express and Honigum display lower flow compared to the other materials, due to their high yield-stress values. Examixfine exhibits the greatest flow. All materials display pseudoplastic behavior, excluding the Examixfine catalyst. The viscosities at low shear rate are greatest for Express and Honigum; however, under high shear conditions, the viscosities of Extrude and Honigum are the lowest. Following mixing, each material show an increase in G', finally reaching a plateau, and the $tan{\delta}$ rapidly decreases with time. Imprint II shows the highest final G' as well as the most rapid decrease in $tan{\delta}$. Express and Imprint II present the highest filler content and rough filler surface, while Honigum shows the lowest filler content and small filler particles. Most products are composed of polymers over 30 kDa and oligomers less than 1 kDa. Each impression material possesses different rheological properties, which significantly affect the handling characteristics. The yield stress of the impression material minimizes unnecessary flow prior to and after seating. Viscoelastic change during setting of each impression material determines the setting time and the stiffness after setting. These rheological properties of impression materials are affected by the filler content and molecular weight distribution of polymer matrix.