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S-N Chen

Publications and source records attributed to S-N Chen.

4 recordsLinked to original sources
PubMed2006

Aqueous extract of Schizandra chinensis fruit causes endothelium-dependent and -independent relaxation of isolated rat thoracic aorta.

An aqueous extract of Schizandra chinensis fruit (ScEx) has long been used to promote the vascular health of postmenopausal women in Korea. This study investigated the ability of ScEx to relax rat aorta constricted with norepinephrine (NE) and the mechanism(s) of such relaxation. ScEx induced partial, endothelium-dependent relaxation. In particular, the relaxation induced by lower concentrations of ScEx (0.1 and 0.3 mg/ml) was largely endothelium-dependent, and was essentially abolished by NG-nitro-L-arginine, methylene blue, 1H-[1,2,3] oxadiazole [4,4-a] quinoxalin-1-one, indomethacin, or ICI 182,780. The results indicate that the response to ScEx involves enhancement of the nitric oxide (NO)-cGMP system, and that it occurs via estrogen receptors. The magnitude of the inhibition with these treatments decreased with increasing ScEx concentration, however, indicating that other vasorelaxation mechanisms are involved, which depend on the ScEx concentration. Calcium concentration-dependent contraction curves in high potassium depolarization medium were shifted significantly to the right and downward after incubation with ScEx (0.3 and 1.0 mg/ml), implying that ScEx is also involved in inhibition of the extracellular calcium influx to vascular smooth muscle. These data demonstrate that ScEx caused both endothelium-dependent and -independent vasorelaxation, which may contribute to understanding the cardiovascular protective effect of ScEx.

Animals↗
PubMed2006

Activation of the mu-opiate receptor by Vitex agnus-castus methanol extracts: implication for its use in PMS.

The dried ripe fruit of Vitex agnus-castus L. (VAC) is widely used for the treatment of premenstrual syndrome (PMS). A previous study reported that extracts of VAC showed affinity to opiate receptors; however, functional activity was not determined. We tested two different VAC extracts in receptor binding and functional assays. Our objectives were: (1) to confirm the opiate affinity; (2) to rule out interference by free fatty acids (FFA); (3) to determine the mode of action of VAC at the mu-opiate receptor. Methanol extracts of VAC were prepared either before (VAC-M1) or after (VAC-M2) extraction with petroleum ether to remove fatty acids. Both extracts showed significant affinities to the mu-opiate receptor, as indicated by the concentration-dependent displacement of [3H]DAMGO binding in Chinese hamster ovary (CHO)-human mu-opiate receptor (hMOR) cells. The IC50 values were estimated to be 159.8 microg/ml (VAC-M1) and 69.5 microg/ml (VAC-M2). Since the defatted extract not only retained, but exhibited a higher affinity (p<0.001), it argued against significant interference by fatty acids. In an assay to determine receptor activation, VAC-M1 and VAC-M2 stimulated [35S]GTPgammaS binding by 41 and 61% (p<0.001), respectively. These results suggested for the first time that VAC acted as an agonist at the mu-opiate receptor, supporting its beneficial action in PMS.

Animals↗
PubMed2004

Removal of sodium from the solvent reduces retinal pigment epithelium toxicity caused by indocyanine green: implications for macular hole surgery.

BACKGROUND: s/aims: Staining of internal limiting membrane with indocyanine green (ICG) has been reported to be associated with postoperative atrophic retinal pigment epithelium (RPE) change. Here the authors examined whether removing sodium from the solvent reduces ICG induced RPE cytotoxicity. METHODS: Human RPE cells were exposed to ICG (0.25 and 0.025 mg/ml) reconstituted with balanced salt solution (BSS) or Na(+) free BSS. Light microscopy, trypan blue dye exclusion, acridine orange/ethidium bromide staining, and DNA electrophoresis were used to evaluate the cytotoxic effects of ICG. ICG uptake was measured by optical absorption at 790 nm. RESULTS: Sodium removal reduced the ICG induced changes in cell morphology and improved the RPE cell viability. When RPE cells were incubated for 4 hours in 0.25 mg/ml ICG dissolved in BSS and sodium free BSS, 86.3% (SD 6.7%) and 2.4% (1.1%) of the cells were stained with trypan blue, respectively. After ICG treatment, RPE dies mainly through a necrotic mechanism. ICG uptake by RPE was also reduced with sodium removal. CONCLUSIONS: ICG induced cytotoxicity in cultured human RPE was reduced with removal of sodium from the solvent. This reconstitution method may provide a safer intravitreal use of ICG in macular hole surgery.

Cells, Cultured↗