• YAKHAK HOEJI
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• v.41 no.6
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• pp.765-772
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• 1997

Conformational analyses on thromboxane $A_2$ (Tx$A_2$) and thromboxane $A_2$ receptor antagonists (TxRA) were carried out by molecular mechanics method. Based on the assumption that active conformer is the nonintrahydrogen bonding and more stable former of Tx$A_2$ and TxRA, the molecular structural requirements for potent TxA2 receptor antagonists are like below: 1) The distance is 5.0-5.6${\AA}$ between C atom of carboxyl group and S atom of sulfonyl group or C atom which is bonded to hydroxyl group in the active conformers. 2) The putative active conformers of Tx$A_2$and TxRAs are hairpin-like forms.

• Journal of Ginseng Research
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• v.18 no.1
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• pp.44-48
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• 1994

In adrenaline-stimulated human platelets, panaxadiol (PD) and panaxatriol (PT) from Panax ginseng C.A. Meyer did not inhibit the $Ca^{2+}$-innux, but inhibited the formation of thromboxane $A_2$ and the platelet aggregations. It seems that PD and PT block a pathyway interconvefing arachidonic acids (20:4) to thromboxane $A_2$ (TX $A_2$), because the amount of $Ca^{2+}$ which phospholipase C or phospholipase $A_2$ requires to liberate 20 : 4 from membrane phospholipids was increased by PD and PT. These results mean that PH and PT have an antiplatelet effect by Inhibiting the formation of TX $A_2$.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.241-247
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• 2000

The present study was designed to assess the protective effect of a selective thromboxane $A_2$ receptor antagonist, KT2-962 (KT2) and possible mechanisms of adriamycin(AD)-induced nephrotoxicity in rats. The male Wistar rats were given either of AD (7.5 mg/kg, i.v.) alone in the AD-group (n=5) or in KT2+AD- group (n=5) which is a combination of AD and KT2 (30 mg/kg/day, i.p.) for 10 days from 3 days before and 7 days after AD injection. The body weight, 24-hours urine volume, urine protein and urinary N-acetyl-$\beta$-D-glu-cosaminidase (NAG) activity were measured with an interval of 2 days during 1 week. BUN, serum creatinine and creatinine clearance were measured on the 7th day. KT2 has significantly suppressed AD-induced change of body weight, 24-hours urine volume, urine protein and urinary NAG activity in the KT2+AD-group. The change of BUN, serum creatinine and creatinine clearance were significantly inhibited in the B7T2+AD-group. Based on these results, it is concluded that KT2 prevents AD-induced nephrotoxicity and suggests that endogenous thromboxane A2 may play an important role in AD-induced nephrotoxicity in rats.

• Analytical Science and Technology
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• v.6 no.4
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• pp.349-357
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• 1993

Analytical methods of thromboxane $B_2(TXB_2)$ using various techniques of Fast Atom Bombardment mass spectrometry (FAB MS) were studied, static FAB condition was investigated to obtain linear response curve using docosanoic acid as a internal standard. For maximum sensitivity, a continuos-flow(CF-) FAB MS by selected-ion monitoring(SIM) with devised sample introduction system, has been developed to quantiate thromboxane $B_2$ in biological sample. Instrumental parameters affecting sensitivity, reproducibility has been studied. The method has been optimized with respect to the eluent, 0.75% glycerol(in EtOH v/v) and flow rate of $3.7{\mu}l/min.$ Under the condition, detection limits were below 10pg in SIM mode and a good linear relationship between dose and response was achieved.

• KSBB Journal
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• v.28 no.1
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• pp.7-12
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• 2013

Thromboxane $A_2$ ($TXA_2$) is one of major proinflammatory mediators, plays an important role in the development of vascular inflammatory diseases. $TXA_2$ acting through the thromboxane receptor regulates multiple pathways and genes in a variety of cells. In this study, we report that the activation of thromboxane receptor with U46619 increases the interleukin-8 (IL-8) mRNA in vascular endothelial cells. We also demonstrated that U46619 produces the activations of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK), which is required for endothelial IL-8 production. And U46619 enhanced mRNA stability of IL-8 transcripts in endothelial cells. Moreover, inhibition of ERK1/2 or p38MAPK reduced monocyte adhesion to aortic endothelium stimulated by U46619. Therefore, these results suggest that activation of thromboxane receptor promotes the expression of IL-8 via ERK1/2 and p38MAPK activation in endothelial cells.

• BMB Reports
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• v.42 no.4
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• pp.200-205
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• 2009

Thromboxane A2 (TBXA2) is a potent vasoconstrictor in cerebral circulation and is a known contributor to the pathogenesis of cerebral infarction. Thromboxane A2 synthase 1 (TBXAS1) and thromboxane A2 receptors (TBXA2R) are key components in TBXA2 function. We examined whether genetic variants in TBXA2R and TBXAS1 are risk factors for cerebral infarction by genotyping 453 Korean patients with noncardiogenic cerebral infarction and 260 controls. A few, specific polymorphisms in the TBXA2R (-3372G>C, +4710T>C and 4839T>C) and TBXAS1 (+16184G>T, +141931A>T and +177729G>A) genes were chosen and investigated. Logistic regression showed the frequencies of TBXAS1+16184G>T and TBXAS1-ht3 were significantly more frequent in cerebral infarction (P = 0.002, OR = 2.75 and P = 0.01, OR = 1.57, respectively), specifically in small-artery occlusion (SAO) type of cerebral infarction (P = 0.0003 and 0.005, respectively). These results suggest specific TBXAS1 gene polymorphisms may be a useful marker for development of cerebral infarction, especially SAO type in Korean population.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.119-122
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• 1992

The affinity chromatographic technique was applied to the isolation of Thromboxane Synthase, with a variety of imidazolyl alkanoic acids coupled Sepharose 2B including a gel (G in Table 4) which has one free COOH group in the bound affinity ligand. The effect of ligand structure on the "affinity" and "selectivity" for thromboxane synthase isolation is described.

• Biomolecules & Therapeutics
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• v.3 no.4
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• pp.301-303
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• 1995

Crude ginseng saponin fraction reduced the production of thromboxane $A_2$in the lipopolysaccharide-stimulated macrophages. Several kinds of crude saponins showed variant potency that might be caused by the compositional difference of ginseng saponins. From the metabolic labeling experimental data, this reduction of thromboxane $A_2$formation, at least in part, resulted from the reduction of protein synthesis of inducible isozyme of cyclooxygenase(COX-2). This activity may be resulted from the fact that ginseng saponins have steroidal moiety in their structures.

• Journal of Nutrition and Health
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• v.27 no.6
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• pp.574-582
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• 1994

The effects of age and dietary fatty acid composition on prostagladin production was investigated in Sprague-Dawley strain male rats. Animals weighing 88.6$\pm$2.2g were fed 10% dietary fat(W/W, 20% of total energy). The P/S ratios of dietary lipid were three levels(0.5, 1, 2) and there were three different levels of n-6/n-3 fatty acid ratio(2, 4, 8) in each P/S ratio. The experimental period were 1 month and 12 months, respectively. The results of this study were as follows. As the age of rats increased, the plasma thromboxane B2 production increased, but aorta 6-keto prostaglandin F1$\alpha$ decreased. When a higher amount of n-3 fatty acid was fed in each P/S ratio, the relative percentage of linolenic acid and EPA in platelet increased.

• Molecules and Cells
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• v.27 no.2
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• pp.191-198
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• 2009

The present study was undertaken to determine whether treatment with genistein, the plant-derived estrogen-like compound influences agonist-induced vascular smooth muscle contraction and, if so, to investigate related mechanisms. The measurement of isometric contractions using a computerized data acquisition system was combined with molecular experiments. Genistein completely inhibited KCl-, phorbol ester-, phenylephrine-, fluoride- and thromboxane $A_2$-induced contractions. An inactive analogue, daidzein, completely inhibited only fluoride-induced contraction regardless of endothelial function, suggesting some difference between the mechanisms of RhoA/Rho-kinase activators such as fluoride and thromboxane $A_2$. Furthermore, genistein and daidzein each significantly decreased phosphorylation of MYPT1 at Thr855 had been induced by a thromboxane $A_2$ mimetic. Interestingly, iberiotoxin, a blocker of large-conductance calcium-activated potassium channels, did not inhibit the relaxation response to genistein or daidzein in denuded aortic rings precontracted with fluoride. In conclusion, genistein or daidzein elicit similar relaxing responses in fluoride-induced contractions, regardless of tyrosine kinase inhibition or endothelial function, and the relaxation caused by genistein or daidzein was not antagonized by large conductance $K_{Ca}$-channel inhibitors in the denuded muscle. This suggests that the RhoA/Rho-kinase pathway rather than $K^+$- channels are involved in the genistein-induced vasodilation. In addition, based on molecular and physiological results, only one vasoconstrictor fluoride seems to be a full RhoA/Rho-kinase activator; the others are partial activators.