Biomedical subjects

M Koeda

Publications and source records attributed to M Koeda.

4 recordsLinked to original sources

PubMed2006

A functional MRI study: cerebral laterality for lexical-semantic processing and human voice perception.

BACKGROUND AND PURPOSE: Language dominance research using functional neuroimaging has made important contributions to clinical applications. Nevertheless, although recent neuroimaging studies demonstrated right-lateralized activation by human voice perception, the influence of voice perception in terms of language dominance has not been adequately studied. We aimed to accurately clarify language dominance for lexical-semantic processing in the temporal cortices by focusing on human voice perception. METHODS: Thirty normal right-handed subjects were scanned by functional MR imaging while listening to sentences (SEN), reverse sentences (rSEN), and identifiable nonvocal sounds (SND). We investigated cerebral activation and the distribution of individual Laterality Index under 3 contrasts: rSEN-SND, SEN-SND, and SEN-rSEN. RESULTS: The rSEN-SND contrast, including human voice perception, revealed right-lateralized activation in the anterior temporal cortices. Both SEN-SND and SEN-rSEN contrasts, including lexical-semantic processing, showed left-lateralized activation in the inferior and middle frontal gyrus and middle temporal gyrus. The SEN-rSEN contrast, without the influence of human voice perception, showed no temporal activation in the right hemisphere. Symmetrical or right-lateralized activation was observed in 22 of 27 subjects (81.4%) under the rSEN-SND contrast in the temporal cortices. Although 9 of 27 subjects (33.3%) showed symmetrical or right-lateralized activation under the SEN-SND contrast in the temporal cortices, all subjects showed left-lateralized activation under the SEN-rSEN contrast. CONCLUSION: Our results demonstrated that right-lateralized activation by human voice perception could mask left-lateralized activation by lexical-semantic processing. This finding suggests that the influence of human voice perception should be adequately taken into account when language dominance is determined.

Adult↗

PubMed1998

Vasoactive effects of cimicifugic acids C and D, and fukinolic acid in cimicifuga rhizome.

Vasoactive effects of cimicifugic acids A-E, fukinolic acid and fukiic acid isolated from Cimicifuga plants were investigated using rat aortic strips. Cimicifugic acid D and fukinolic acid at 3x10(-4) M caused a sustained, slowly developing relaxation of aortic strips precontracted with norepinephrine (NE) in preparations with or without endothelium. Cimicifugic acid C inversely caused a weak contraction. Cimicifugic acids A, B and E and fukiic acid showed no vasoactivity at 3x10(-4) M. Cimicifugic acids A-E and fukinolic acid are esters between cinnamic acids and the hydroxyl group of benzyltartaric acids. For the manifestation of vasoactivity in the rat aorta, it is concluded that in the cinnamic acid moiety, a caffeoyl group might be necessary for the relaxation activity, and the p-coumaroyl group causes contraction. Concentration response curves for the Ca2+-induced contracture of depolarized aortic strips with isotonic high K+ were not affected by cimicifugic acid D or fukinolic acid. The Ca2+-induced contraction of aortic strips, preincubated with 10(-6) M NE in the presence of 10(-6) M nicardipine and 0.01 mM EGTA in Ca2+-free solution, were inhibited by cimicifugic acid D and fukinolic acid. These results indicated that the inhibition by cimicifugic acid D and fukinolic acid of the NE-induced contraction of rat aorta are attributable to the suppression of Ca2+ influx from the extracellular space enhanced by NE.

Animals↗

PubMed1995

Studies on the Chinese crude drug "shoma." IX. Three novel cyclolanostanol xylosides, cimicifugosides H-1, H-2 and H-5, from cimicifuga rhizome.

Three new cyclolanostanol xylosides were isolated from a batch of commercial Cimicifuga Rhizome, cimicifugoside H-1 (1), C35H52O9, mp 260-262 degrees C, [alpha]D -43.5 degrees, cimicifugoside H-2 (2), C35H54O10, mp 227-229 degrees C, [alpha]D -38.8 degrees, and cimicifugoside H-5 (3), C35H52O10, mp 262-264 degrees C, [alpha]D -22.9 degrees, together with known glycosides, actein and 27-deoxyactein. Their structures were determined on the basis of chemical and spectrometric evidence including an X-ray crystallographic analysis. The structure of cimicifugoside H-1 (1) was established as (20R,24R)-24,25-epoxy-11 beta-hydroxy-3-beta-(beta-D- xylopyranosyloxy)-9,19-cyclolanost-7-ene-16,23-dione. Cimicifugoside H-5 (3) is the 15-hydroxylated derivative of 1. Since 1 changed into cimicifugoside H-2 (2) on treatment with p-toluenesulfonic acid, 2 has a 24R,25-diol structure derived from 1 by opening its epoxy ring.

Analgesics, Non-Narcotic↗

PubMed1994

Studies on the Chinese crude drug "Shoma." VIII. Two new triterpenol bisdesmosides, 3-arabinosyl-24-O-acetylhydroshengmanol 15-glucoside and 3-xylosyl-24-O-acetylhydroshengmanol 15-glucoside, from Cimicifuga dahurica.

Two new triterpenol glycosides were isolated from the rhizomes of Cimicifuga dahurica (Ranunculaceae): 3-arabinosyl-24-O-acetylhydroshengmanol 15-glucoside (1), C43H70O16, mp 222-223 degrees C, [alpha]D +21.0 degrees and 3-xylosyl-24-O-acetylhydroshengmanol 15-glucoside (2), C43H70O16, mp 208-210 degrees C, [alpha]D +9.5 degrees. On acidic hydrolysis, 1 afforded cimigenol (3) as an aglycone, and glucose and arabinose as sugars. On enzymatic hydrolysis with molsin, 1 afforded 24-O-acetylhydroshengmanol 15-O-glucoside (4). On the basis of chemical and spectral data, the structure of 1 was proposed to be (23R,24S)-24-acetoxy-3-O-alpha-L-arabinopyranosyloxy-16,23-e poxy-9,19- 15-O-beta-D-glucopyranoside. The other glycoside (2) showed, in its 13C-NMR spectrum, a pattern of chemical shifts very similar to that of 1. On acidic hydrolysis, 2 afforded cimigenol (3), xylose and glucose. On enzymatic hydrolysis with molsin, 2 afforded 4. From these results, the structure of 2 was proposed to be (23R,24S)-24-acetoxy-3-O-beta-D-xylopyranosyloxy-16,23-epoxy -9,19-cyclolanostane-15 alpha,16 xi,25-triol 15-O-beta-D-glucopyranoside.

Drugs, Chinese Herbal↗