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Biomedical subjects

Y H Kuo

Publications and source records attributed to Y H Kuo.

At least 55 records · Page 3Linked to original sources
PubMed2000

A novel anti-HBeAg homolignan, taiwanschirin D from Kadsura matsudai.

A novel C19 homolignan, taiwanschirin D (1), possessing a 3,4-(1-[(Z)-2-methoxy-2-oxoethylidenel)pentano (2,3-dihydrobenzo[b]furan)-3(2-oxoacetate) skeleton, was isolated from the stem of Kadsura matsudai Hayata. Its structure was determined from physical and spectral data including 2D NMR spectra. The Anti-HBeAg test revealed that taiwanschirin D (1) had moderate activity at a concentration of 94.3 microM (50 microg/ml).

Antineoplastic Agents↗
PubMed2000

A novel cytotoxic C-methylated biflavone from the stem of Cephalotaxus wilsoniana.

Bioassay-directed fractionation of an ethanolic extract of Cephalotaxus wilsoniana has resulted in the isolation of a novel C-methylated biflavone, taiwanhomoflavone-A (1). Its structure was elucidated on the basis of spectroscopic analysis. Taiwanhomoflavone-A is cytotoxic with ED50 values of 3.4, 1.0, 2.0 and 2.5 microg/ml, respectively, against KB epidermoid carcinoma of nasopharynx, COLO-205 colon carcinoma, Hepa-3B hepatoma, and Hela cervix tumor cells.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Six new ursane- and oleanane-type triterpenes from the aerial roots of Ficus microcarpa.

Four new ursane-type triterpenes, 3beta-acetoxy-11alpha-methoxy-12-ursene (1), 3beta-acetoxy-11alpha-ethoxy-12-ursene (2), 3beta-acetoxy-11alpha-hydroperoxy-12-ursene (3), 3beta-hydroxy-11alpha-hydroperoxy-12-ursene (4), and two new oleanane-type triterpenes, 3beta-acetoxy-11alpha-ethoxy-12-oleanene (5), 3beta-acetoxy-111alpha-hydroperoxy-12-oleanene (6), together with 3beta-acetoxy-11alpha-hydroxy-12-ursene (7), 3beta,11alpha-diacetoxy-12-ursene (8), 3beta-acetoxy-11alpha-hydroxy-12-oleanene (9), were isolated from the aerial roots of Ficus microcarpa L. f. Their structures were elucidated by spectroscopic and chemical methods.

Magnetic Resonance Spectroscopy↗
PubMed2000

Six podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides.

Six podocarpane-type trinorditerpenes were isolated from the bark of Taiwania cryptomerioides. Their structures, 14-hydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (1), 13-hydroxy-12-methoxy-8,11,13-podocarpatriene (2), 12-hydroxy-13-methoxy-8,11,13-podocarpatriene (3), 14-hydroxy-13-methoxy-8,11,13-podocarpatriene (4), 13-hydroxy-8,11,13-podocarpatriene (5), and 13,14-dihydroxy-8,11,13-podocarpatrien-7-one (6), were determined principally from spectral evidence.

Diterpenes↗
PubMed2000

Four new terpenes from the pericarp of Platycladus orientalis.

A new monoterpene, platydiol (1), and three new diterpenes, platyclolactonic acid (2), 14,15-bisnor-8(17)-labdene-16,19-dioic acid (3), and 6,7-dehydrosandaracopimaric acid (4), were isolated from the pericarp of Platycladus orientalis. Their structures were elucidated by spectral and chemical methods.

Molecular Structure↗
PubMed1999

Substantial decrease of heat-shock protein 90 precedes the decline of sperm motility during cooling of boar spermatozoa.

The decline in boar semen quality after cryopreservation may be attributed to changes in intracellular proteins. Thus, the aim of the present study was to evaluate the change of protein profiles in boar spermatozoa during the process of cooling and after cryopreservation. A total of 9 sexually mature boars (mean age = 25.5+/-12.3 mo) was used. Samples for protein analysis were collected before chilling, after cooling to 15 degrees C, after cooling to 5 degrees C, following thawing after freezing to -100 degrees C, and following thawing after 1 wk of cryopreservation at -196 degrees C. Semen characteristics evaluated included progressive motility and the percentage of morphologically normal spermatozoa. Total proteins from 5x10(6) spermatozoa were separated and analyzed by SDS-PAGE. The results revealed that there was a substantial decrease of a 90 kDa protein in the frozen-thawed spermatozoa. Western blot analysis demonstrated that this protein was 90 kDa heat-shock protein (HSP90). Time course study showed that the decrease of HSP90 in spermatozoa initially occurred in the first hour during cooling to 5 degrees C. When compared with the fresh spermatozoa before chilling, there was a 64% decrease of HSP90 in spermatozoa after cooling to 5 degrees C. However, the motility and percentage of normal spermatozoa did not significantly decrease during this period of treatment. Both declined substantially as the semen was thawed after freezing from -100 degrees C. The results indicated that the decrease of HSP90 precedes the decline of semen characteristics. The length of time between a decrease of HSP90 and the decline in sperm motility was estimated to be 2 to 3 h. Taken together, the above results suggested that a substantial decrease of HSP90 might be associated with a decline in sperm motility during cooling of boar spermatozoa.

Animals↗
PubMed1999

Decreasing occupational risk related to blood-borne viruses in cardiovascular surgery in Paris, France.

BACKGROUND: Surgeons face the risk of patient-to-physician transmission of blood-borne viruses. This risk is related to the seroprevalence of the viruses in the patient population. METHODS: The seroprevalence of the human immunodeficiency virus, hepatitis B virus, and hepatitis C virus were determined in cardiovascular patients at Hôpital Broussais in Paris, France, over a 5-year period (1994 to 1998). RESULTS: Hepatitis C virus is the most prevalent virus in the patient population, whereas human immunodeficiency virus is the least frequent. The seroprevalence of hepatitis C virus and human immunodeficiency virus has decreased over time, whereas hepatitis B virus has remained constant. We apply the seroprevalence data to a mathematical model to estimate the occupational risk of seroconversion faced by surgeons over the length of their career. Our results show that the principal risk faced by the surgeon arises from hepatitis B virus and hepatitis C virus. The decreasing seroprevalence of the hepatitis C virus has resulted in a decrease in the occupational risk. CONCLUSIONS: The probability of becoming infected with a blood-borne virus over the career of the surgeon is notable. The greatest occupational risk to the surgeon is from the hepatitis viruses and not HIV.

Adolescent↗
PubMed1999

Antioxidant principles from Ephemerantha lonchophylla.

One dihydrostilbene and three phenanthrene antioxidants were isolated from an ethanolic extract of the Chinese herbal Ephemerantha lonchophylla. One of these compounds, ephemeranthone (4) is a new natural product. Denbinobin (1) and 3-methylgigantol (3) have been previously isolated from this plant, and 3-ethoxy-5-hydroxy-7-methoxy-1,4-phenanthraquinone (2) is an artifact. The structures of these compounds were determined by spectroscopic analysis. The antioxidative activities for inhibiting human low density lipoprotein oxidation in vitro of compounds 1-4 were determined, and only 4 was active (5.3 times that of probucol).

Antioxidants↗
PubMed1999

Inhibition of low density lipoprotein oxidation by tetrahydrofurofuran lignans from Forsythia suspensa and Magnolia coco.

Based on the inhibition of Cu(2+)-induced LDL oxidation as marker, the major antioxidants in the fruits of Forsythia suspensa and the stems of Magnolia coco were identified. Of these bioactive tetrahydrofurofuran lignans, pinoresinol, phillygenin, and syringaresinol were more potent than probucol. Sesamin and fargesin, which do not contain phenol groups, were found much less active.

Furans↗
PubMed1999

Sympathetic ophthalmia associated with cyclitis: case report.

We present a case of sympathetic ophthalmia. A 41-year-old man suffered a penetrating injury to his right eye. Six weeks after the injury he complained of photophobia and redness in his left eye. Visual acuity without correction was: right eye (RE), no light perception; and left eye (LE), 1.0. Ocular examination of the left eye revealed a shallow anterior chamber and mildly elevated intraocular pressure (25 mmHg). An initial diagnosis of narrow angle glaucoma was made and antiglaucomatous agents were prescribed. One month after diagnosis the vision in his left eye suddenly dropped to 0.04. Ocular examination showed annular serous retinal detachment and scattered yellow-white lesions (Dalen-Fuchs Nodules). Under the diagnosis of sympathetic ophthalmia, high dose intravenous corticosteroid (methylprednisolone, 200 mg daily) and subtenon dexamethasone (4 mg/0.8 cc) were used. Ten days after beginning treatment the vision improved to 0.1 but the retinal detachment was not sealed completely. Oral prednisolone (100 mg daily) and cyclosporine (125 mg bid) therapy replaced the intravenous corticosteroids. The serum level of Cyclosporine was 118 ng/ml. After 3 months the vision improved to 0.6 and the retinal detachment subsided. Renal function and hematocrit status were monitored closely and no abnormal conditions were noted.

Adrenal Cortex Hormones↗
PubMed1998

Sesquiterpenes from the leaves of Tithonia diversifolia.

Two new compounds, a germacrane sesquiterpene, 1-acetyltagitinin A (1), and a guaianane sesquiterpene, 8beta-isobutyryloxycumambranolide (2), were isolated from leaves of Tithonia diversifolia, together with two known compounds, methyl 3alpha-acetoxy-4alpha-hydroxy-11(13)-eudesmen-12-oa te and tagitinin A. The structures of compounds 1 and 2 were elucidated on the basis of spectral and chemical evidence.

Carbohydrate Sequence↗
PubMed1998

New diterpenes from the heartwood of Chamaecyparis obtusa var. formosana.

An abietane diterpene, 11,14-dihydroxy-8,11,13-abietatrien-7-one (1); a seco-abietane diterpene, obtuanhydride (2); and an isopimarane diterpene, 18,19-O-isopropylidene-18, 19-dihydroxyisopimara-8(14),15-diene (3) were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structures of these new compounds were elucidated by spectroscopic methods.

Abietanes↗
PubMed1998

A new taxane diterpenoid from Taxus mairei.

A new 11(15-->1)-abeotaxane diterpene, taxumairol K (1), has been isolated from the ethanolic extract of the roots of Formosan Taxus mairei (Lemee & Levl.) S. Y. Hu. The structure of 1 was determined as 9alpha-(benzoyloxy)-2alpha,4alpha- diacetoxy-5beta ,20-epoxy-1beta, 7beta,10beta,13alpha-tetrahydroxy-11(15-->1)-abeota xane on the basis of spectral analysis. Taxumairol K (1) exhibited mild cytotoxicity against HeLa tumor cells.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Four new sesquiterpenes from Petasites formosanus.

Four new eremophilane-type sesquiterpenes, petasones A (1) and B (2), S-petasitin (3), and petasinol (4), were isolated from the aerial parts of Petasites formosanus. Their structures were elucidated by spectroscopic and chemical methods as 3alpha-[(Z)-3-methylsulfinylacryloxy]eremophila-7(11), 9-dien-8-one; 3alpha-[(E)-3-methylsulfinylacryloxy]eremophila-7(11), 9-dien-8-one; 3alpha-[(Z)-3-methylthioacryloxy]-11-hydroxyeremophila -6, 9-dien-8-one; and 3alpha-[(E)-3-methylsulfinylacryloxy]-8beta-hydroxy eremophila-9, 11-diene, respectively.

Carbohydrate Sequence↗
PubMed1998

Five new diterpenoids from the wood of Cunninghamia konishii.

Five new diterpenes, 3beta-acetoxyabieta-8,11,13-trien-12-ol (1), 8alpha-hydroxy-13(16),14-labdadien-19-al (2), 16-hydroxy-19-oxomanoyl oxide (3), 15-nor-14-oxo-8(17), 12-labdadiene-18-ol (4), and 15,16-bisnor-13-oxo-8(17), 11-labdadien-18-ol (5), were isolated from the wood of Cunninghamia konishii. Their structures were elucidated by 2D NMR spectroscopy and by chemical methods.

Carbohydrate Sequence↗