• Preventive Nutrition and Food Science
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• 제9권4호
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• pp.295-299
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• 2004

Alpha-tocopherol was thermally oxidized and degraded at high temperatures and the resulting products were chromatographically separated and identified by LC-MS. Alpha-tocopherol dissolved in glycerol was heated at 200^{\circ}C for 30 min. The thermal products were separated by hexane extraction and analyzed by HPLC using a reversed phase $\mu$-Bondapak $C_{18}-column$ with two kinds of elution solvents: a mixture of acetonitrile and methanol (3:2), and of acetonitrile, methanol, 2-propanol, chloroform and methylene chloride (3:2:5:0.5:0.5) in a gradient mode. The isolated thermal. products of alpha-tocopherol were more viscous than alpha-tocopherol, and dark brown in color. Major thermal degradation products of alpha-tocopherol were identified by LC-MS, and the structures of thermal products were proposed. Alpha-tocopherol and its thermal degradation products were degraded into fragments, mainly at the non-aromatic parts. The degradation products of alpha-tocopherol. were combined with oxidized product (tocopherylquinone) to make thermal. products through dimerization.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제5권1호
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• pp.1-3
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• 1998

Let f : X longrightarrow Y be quasi-open. We show that: (1) If A $\subset$ X is open, f│A is quasi-open, (2) f : X longrightarrow f(X) is quasi-open. (3) And let $f_{\alpha}/,:X_{\alpha}$, longrightarrow $Y_{\alpha}$ be quasi-open. Then $\Pi f_{\alpha}, : \Pi X_{\alpha}$ longrightarrow $\Pi Y_{\alpha}$/ defined by {$x_{\alpha}$} longrightarrow {$f_{\alpha},({\chi}_{\alpha}$)}, is quasi-open. (4) Lastly, if $f_{i}: X_{i}$ longrightarrow Y are quasi-open, i = 1,2, then F: $X_1 \bigoplus X_2$ longrightarrow Y, defined by $F({\chi})=f_i({\chi})$, ${\chi} \in X_i$, is also quasi-open.

• 약학회지
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• 제30권3호
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• pp.157-162
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• 1986

$\alpha$-Adrenoceptor subtypes in the isolated rat aortic strips were examined by using agonists and antagonists which have varying selectivity for $\alpha_1$- and $\alpha_2$- adrenoceptors. Norepinephrine and phenylephrine produced a similar magnitude of maximum contractions. $pA_2$ values for prazosin and yohimbine were not significantly different using norepinephrine or phenylephrine as the agonist, suggesting a single population of alpha-adrenoceptor. Contractile responses produced by alpha-agonists were antagonized more effectively by prazosin (approximately 1000 fold) than by yohimbine.

• Journal of Microbiology and Biotechnology
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• 제20권6호
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• pp.1011-1017
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• 2010

A novel dioscin-glycosidase that specifically hydrolyzes multi-glycosides, such as 3-O-${\alpha}$-L-($1{\to}4$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, and ${\beta}$-D-glucoside, on diosgenin was isolated from the Absidia sp.d38 strain, purified, and characterized. The molecular mass of the new dioscin-glycosidase is about 55 kDa based on SDS-PAGE. The dioscin-glycosidase gradually hydrolyzes either 3-O-${\alpha}$-L-($1{\to}4$)-Rha or 3-O-${\alpha}$-L-($1{\to}2$)-Rha from dioscin into 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin, further rapidly hydrolyzes the other ${\alpha}$-L-Rha from 3-O-${\alpha}$-L-Rha-${\beta}$-D-Glc-diosgenin into the main intermediate products of 3-O-${\beta}$-D-Glc-diosgenin, and subsequently hydrolyzes these intermediate products into aglycone as the final product. The enzyme also gradually hydrolyzes 3-O-${\alpha}$-L-($1{\to}4$)-arabinoside, 3-O-${\alpha}$-L-($1{\to}2$)-rhamnoside, and ${\beta}$-D-glucoside from [3-O-${\alpha}$-L-($1{\to}4$)-Ara, 3-O-${\alpha}$-L-($1{\to}4$)-Rha]-${\beta}$-D-Glc-diosgenin into diosgenin as the final product, exhibiting significant differences from previously reported glycosidases. The optimal temperature and pH for the new dioscin-glycosidase is $40^{\circ}C$ and 5.0, respectively. Whereas the activity of the new dioscin-glycosidase was not affected by $Na^+$, $K^+$, and $Mg^{2+}$ ions, it was significantly inhibited by $Cu^{2+}$ and $Hg^{2+}$ ions, and slightly affected by $Ca^{2+}$ ions.

• Applied Microscopy
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• 제32권3호
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• pp.223-230
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• 2002

Sprague-Dawley rat에 complete Freund's adjuvant (CFA)를 투여하여 유발한 골다공증에 미치는 $1{\alpha}$, 25 dihydroxyvitamin $D_3\;(Vit\;D_3)$의 효과를 알아보기 위하여 실험동물을 정상 대조군, CFA 투여 대조군, CFA 투여후 $1{\alpha}$, 25 dihydroxyvitamin $D_3\;0.01{\mu}g/kg$ 투여군 (Vit $D_{3}L$) 및 $0.1{\mu}g/kg$ 투여군(Vit $D_{3}H$)으로 분류하여 경구로 3주간 투여하였다. 골다공증의 억제 효과를 알아보기 위하여 골밀도와 골함유량의 변화 및 주사전자현미경적 소견을 관찰한 결과 다음과 같은 결론을 얻었다. 골밀도와 골함유량은 $1{\alpha}$, 25 dihydroxyvitamin $D_3$ 투여용량과 부위에 따라 차이가 있었는데 Vit $D_3$ 투여군이 CFA 투여 대조군과 비교하여 골밀도와 골함유량이 증가하였으며 Vit $D_{3}H$군이 Vit $D_{3}L$군보다 좀 더 효과적이었다. 대퇴골의 주사전자현미경적 소견은 Vit $D_3$ 투여군의 골피질과 골소주의 손상이 CFA 투여 대조군보다 억제되었음을 볼 수 있었으며 Vit $D_{3}H$ 투여군이 Vit $D_{3}L$ 투여군보다 좀 더 효과적이었다. 이상의 결과를 종합해 보면 $1{\alpha}$, 25 dihydroxyvitamin $D_3$의 투여는 CFA에 의해 유발된 rat의 골다공증 모델에서 골다공증의 진행을 억제하였고 Vit $D_{3}H$ 투여군이 Vit $D_{3}L$ 투여군보다 좀 더 효과적이었다.

• 대한의생명과학회지
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• 제19권1호
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• pp.1-8
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• 2013

Parkin is known to be a tumor suppressor protein. Previously, we determined that parkin expression restores susceptibility to TNF-${\alpha}$-induced death of HeLa cells, a human cervical cancer cell line resistant to TNF-${\alpha}$-induced cell death. MMP-3 is a zinc-dependent protease recently reported to activate intracellular apoptotic signaling. In this study we examined the regulation of MMP-3 expression by parkin in TNF-${\alpha}$-treated HeLa cells. Furthermore, we investigated the signaling pathway involved in parkin-induced expression of MMP-3. We found that HeLa cells exhibit low levels of MMP-3 but is induced after introduction of the parkin gene into HeLa cells. Furthermore, MMP-3 expression increased further when parkin expressing cells were treated with TNF-${\alpha}$. Using chemical inhibitors of cell signaling pathways, we found that MEK-1 (PD98059), PI3K (LY294002), p38 MAPK (SB203580), and JNK inhibitors alleviated parkin-induced up-regulation of MMP-3. Finally, we show that TNF-${\alpha}$-induced cell death in parkin expressing cells is inhibited by using a MMP-3 inhibitor. These results suggest that parkin expression induces prolonged expression of MMP-3 via MEK-1, PI3K, MAPK, and JNK pathway in HeLa cells allowing the HeLa cells to become sensitive to TNF-${\alpha}$-induced cell death. These results implicate a role of MMP-3 in parkin-induced cell death in TNF-${\alpha}$ treated HeLa cells.

• 약학회지
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• 제40권6호
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• pp.734-738
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• 1996

The development of the alpha2 isoform of (Na,K)ATPase which is high affinity ouabain receptors was studied in the differentiating nonfusing muscle cell line BC3H-1. T he differentiation process of BC3H-1 cell line was confirmed by 2-dexy-D-[$^3$H] glucose uptake experiment and the quantity of the expression of ${\alpha}_2$ isoform was measured using a whole cell [$^3$H] ouabain-binding assay. Undifferentiated growing BC3H-1 cells, myoblasts, exhibited low levels of insulin-stimulated glucose uptake and [$^3$H] ouabain-binding sites. In contrast, differentiated BC3H-1 cells, myocytes, had a 5.6-fold increase in insulin-stimulated glucose uptake and 5-fold increase in [$^3$H] ouabain-binding sites. Scatchard analysis showed that myocytes developed more [$^3$H] ouabain-binding sites than myoblasts vath a dissociation constant (kd) of 6${\times}10^{-8}$M and capacity of 6.l${\times}10^{-5}$ sites/cell. Therefore. it seems that myoblasts express low levels of ${\alpha}_2$ subunit and probably the majority of ${\alpha}_1$ subunit, whereas myocytes express high levels of ${\alpha}_2$ isoform. The results indicate that the expression of ${\alpha}_2$ isoform is developmentally regulated during differentiation and that BC3H-1 culture system provides an excellent model for the study of differentiation and mechanism of (Na,K)ATPase action in muscle which requires electrical excitability.

• 약학회지
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• 제51권6호
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• pp.495-499
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• 2007

Seven epoxy- and hydroxyandrostane derivatives ($DH-1{\sim}DH-7$) and nine epoxy- and hydroxycholestane derivatives ($CH-1{\sim}CH-9$) with unsaturation in ring A and ring B were synthesized from DHEA and cholesterol, respectively. The antinociceptive effects of all synthesized compounds were measured by hot plate method. Most of androstane derivatives except $1{\alpha},2{\alpha}$-epoxy-4,6-androstadiene-3,17-dione (DH-3), and CH-6, CH-7 and CH-9 exhibited antinociceptive effect. 1,4-Androstadiene-$3{\beta},17{\beta}$-diol (DH-5, 100 mg/kg, $35.8{\pm}7.39$), $6{\alpha},7{\alpha}$-epoxy-1,4-androstadiene-3,17-dione (DH-4, 100 mg/kg, $32.6{\pm}5.50$) and $5{\alpha},6{\alpha}$-epoxy-17-oxo-androstan-$3{\beta}$-ol (DH-1, 100 mg/kg, $32.5{\pm}2.98$) were more effective than morphine (10 mg/kg, $30.6{\pm}0.5$). The analgesic effects of androstane derivatives on acetic acid writhing in mice were lower than aspirin. The androstane derivatives were less effective than ibuprofen at inhibiting effects on the carrageenin induced paw oedema. 4,6-Cholestadien-$3{\beta}$-ol (CH-5), $1{\alpha},2{\alpha}$-epoxy-4,6-cholestadien-$3{\beta}$-ol (CH-7) and $7{\alpha}$-hydroxy4-cholesten-3-one (CH-9) showed the decrease of serum triglyceride and total cholesterol levels in poloxamer P-407 injected rat.

• Journal of Photoscience
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• 제1권2호
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• pp.123-126
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• 1994

Irradiation of aromatic $\alpha$-diketones, such as benzil, 4,4'-dimethylbenzil, 4-chlorobenzil, 4,4'-diisopropylbenzil, 3,3,'-dimethylbenzil, in methanol gives rise to xanthone derivatives, in addition to $\alpha$-hydroxyketones. Irradiation of 4,4'-dibromobenzil, 2,2'-pyridil, 2,2'-naphthil and 9,9'-anthril yields only $\alpha$-hydroxyketones, whereas 4,4'-dimethoxybenzil yields methyl 4-methoxybenzoate.

• 한국표면공학회지
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• 제49권1호
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• pp.69-74
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• 2016

In order to investigate the effect of NiO on the ethanol gas sensing performance of ${\alpha}-Fe_2O_3$ nanoparticles, NiO and ${\alpha}-Fe_2O_3$ nanoparticles are synthesized by hydrothermal method. The sensor with ${\alpha}-Fe_2O_3$ and NiO nanoparticles mixed at an optimum ratio of 7:3 showed 3.8 times improved sensing performance for 200ppm ethanol gas at $200^{\circ}C$. The enhanced gas sensing performance can be considered to be caused by pn heterojunction at the grain boundaries of ${\alpha}-Fe_2O_3$ and NiO nanopartcles.