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Biomedical subjects

J S Yang

Publications and source records attributed to J S Yang.

At least 109 records · Page 6Linked to original sources
PubMed1992

[Triterpene constituents from Euphorbia nematocypha Hand-Mazz].

Seven triterpenoids have been isolated from the roots of Euphorbia nematocypha Hand-Mazz. through chromatography on 20% AgNO3-silica gel. One of them was identified as a new compound named nematocyphol on the basis of spectral data (IR, EIMS, 1H-NMR and 13C-NMR). Its structure was deduced as IVa. Other compounds were identified as nepehinol acetate (I), germanicol acetate (II), euphol (III), tanaxastanol (Va), 24-methylenecycloartanol (VIa) and nepehinol (VIIa). These compounds were obtained for the first time from this plant.

Drugs, Chinese Herbal↗
PubMed1991

TTX-sensitive and TTX-insensitive sodium channel mRNA transcripts are independently regulated in adult skeletal muscle after denervation.

The expression of mRNA encoding the TTX-sensitive (SkM1) and TTX-insensitive (SkM2) voltage-dependent sodium channels in adult skeletal muscle is independently regulated. In normal skeletal muscle, only the SkM1 message is expressed and the level varies with muscle fiber type. After surgical denervation, the steady-state SkM1 mRNA level declines transiently, but returns to control levels within 5 days. Expression of SkM2 transcripts is markedly activated, reaching a peak 3 days after axotomy and then declining to a maintained level at approximately 30% of peak. Chemical denervation with botulinum toxin results in higher levels of SkM2 mRNA, which by 7 days posttreatment are 7-fold greater than levels in paired axotomized muscles. SkM2 expression subsequently declines as functional reinnervation appears. Quantal acetylcholine release appears to play a major role in suppression of SkM2 expression in adult innervated or reinnervated muscle, whereas nonquantal factors in toxin-treated, but not axotomized, muscle may sustain high level SkM2 mRNA expression.

Animals↗
PubMed1991

Facial nerve paralysis associated with Kawasaki disease.

Kawasaki disease is a multisystem disorder with varying clinical expression. This is a report on one case of Kawasaki disease which during its clinical course developed facial nerve palsy and spontaneous recovery without specific treatment. It is hoped that this report will serve to remind physicians of the association of facial nerve paralysis with Kawasaki disease.

Aspirin↗
PubMed1991

[A comparative study of antinuclear antibody measurement using different cells as nuclear substrates].

In an attempt to evaluate possible variations in the antinuclear antibody (ANA) titers resulting from nuclear substrate difference, we measured the ANA titer of 104 normal subjects using substrates from mouse liver cell (MLC) and HEp-2 cell (CSI, USA). We also performed similar experiments on 50 sera from 50 patients with rheumatic disease using mouse liver cell, HEp-2 cell (CSI), HEp-2 cell (AFT, Japan), and HEp-2 cell (AI, USA) as substrates. The ANA titer assay using HEp-2 cell (CSI), which is routinely used in our laboratory, was regarded as the reference method. The results showed that when HEp-2 (CSI) was used, 98.1% normal subjects had ANA titer lower than 1:320, therefore a cut-off value of 1:320 was used. While using the MLC method, 96.2% normal subjects had ANA titer lower than 1:80, and the cut-off value was set at 1:80 accordingly. The geometric mean ANA titers of the 50 sera from 50 rheumatic disease patients were 676 for HEp-2 cell (CSI), 503 for HEp-2 cell (AFT), 368 for HEp-2 cell (AI), and 265 for MLC, respectively. Although statistically significant difference (p less than 0.05) in geometric mean titer existed between reference method and the other 3 methods, the latter 3 methods still had good sensitivity (97.2% for HEp-2 cell (both AFT and AI); 91.7% for MLC), and specificity (100% for HEp-2 cell (both AFT and AI); 71.4% for MLC) for selecting out sera with abnormal ANA titer. We also evaluated the relationships between ANA titer and anti-double stranded DNA antibody (anti-dsDNA) concentration in another 210 sera from 151 patients with rheumatic disease. Statistically, there is no distinct correlation between anti-dsDNA and ANA of all fluorescence staining patterns except for peripheral pattern, in which case a significant correlation could be demonstrated.

Adolescent↗
PubMed1991

[Chemical constituents of Armillaria mellea mycelium. VII. Isolation and characterization of chemical constituents of the acetone extract].

Eight compounds were isolated from the acetone extract of artificially cultured mycelium of Armillaria mellea (Vahl. ex Fr.)Quel.(Tricholomataceae). Three of them are protoilludane sesquiterpenoid aromatic esters. Their structures were elucidated by spectral data analysis as the known 4'-methylmelledonal (I)and two new compounds named armillaritin (II) and armillarivin (III). In addition, five known compounds were identified as D-erythritol, D-mannitol, azelaic acid, orsellinic acid and glycerin-alpha-monooleate.

Agaricales↗
PubMed1991

[Studies on chemical constituents of Veronica lina riifolia Pall. ex Link. sub. dilatata (Nakai et Kitagawa) Hong].

A new flavonoid glycoside, named linariifolioside, C29H32O17 with mp at 232-234 degrees C (dec.), was isolated from the alcohol extract of the dried whole herb of Veronica linariifolia Pall. ex Link sub. dilatata (Nakai et Kitagawa) Hong. Based on spactral (IR, UV, 1HNMR, 13CNMR and FAB-MS) analysis and hydrolysis products its structure was identified as luteolin-7-O-6"'-O-acetyl-beta-D-glucosyl-(1----2)-beta-D-glucoside (I). In addition, four known compounds, luteolin-7-O-beta-D-glucosyl-(1----2)-beta-D-glucoside (II), apigenin-7-O-alpha-L-rhamnoside (III), luteolin (IV), and apigenin (V) were isolated from the same fraction and identified. These compounds were obtained for the first time from this plant.

Drugs, Chinese Herbal↗
PubMed1991

Pseudoxanthoma elasticum. A report of 5 cases in one family.

Five cases of pseudoxanthoma elasticum (PXE) found in one family are reported. The hereditary pattern is probably of autosomal dominant type 2. In the fundi of all the 5 cases, mottlings of the retinal pigment epithelium or orange skin-like lesions in both eyes which are of significant diagnostic importance are seen. The fundus changes are more prominent when skin lesions are typical. Under electron and light microscope, the pathological changes of clinically typical and atypical lesions show similar characteristics of this disorder. Remarkable calcification of elastic fibers with abnormal contour and fragmentation, destruction of mitochondria of fibroblasts and a great number of mast cells leaning against fibroblasts are the chief findings in the histochemically stained specimens. The pathogenetic mechanism of this disorder is possibly dystrophy of elastic fibers with its inherent nature of being easily calcified. Involvement of autoimmune factors in the pathogenesis is quite possible.

Adult↗
PubMed1990

A novel N6-substituted adenosine isolated from mi huan jun (Armillaria mellea) as a cerebral-protecting compound.

Successive purification of a crude extract of cultured Mi Huan Jun mycelia, followed by an assay of the effect on complete ischemia in mice, led to the isolation of a new compound with cerebral protecting activity, hereafter designated as AMG-1. The structure of AMG-1 was proposed as being 6-(5-hydroxy-2-pyridyl-methylamino)-9-beta-ribofuranosylpurine (1) on the basis of its UV, mass, 1H-NMR, and 13C-NMR spectra.

Adenosine↗
PubMed1990

Armillaric acid, a new antibiotic produced by Armillaria mellea.

A new antibiotic armillaric acid (2), has been isolated from the cultured mycelia of Armillaria mella (Vahl. ex Fr.) Quel (Trichlometaceae). Its structure was elucidated on the basis of the spectral data. Compound 2 exhibits inhibitory activity against gram-positive bacteria and yeast.

Agaricales↗
PubMed1990

[Studies on the chemical constituents of Aquilaria sinensis (Lour.) Gilg. V. Isolation and characterization of three 2-(2-phenylethyl) chromone derivatives].

Three 2-(2-phenylethyl) chromone derivatives were isolated from the ethyl acetate soluble fraction of the alcoholic extract of Aquilaria sinensis (Lous.) Gilg. (Thymeleaceae) by silica gel chromatography. Based on spectral data (UV, IR, 1HNMR, 13CNMR and MS) two of them are new compounds and their structures were identified as 5,8-dihydroxy-2-(2-p-methoxyphenylethyl) chromone (2) and 6,7-dimethoxy-2-(2-p-methoxyphenylethyl) chromone (3). The known compound siolated for the first time from this plant, was identified as 5,8-dihydroxy-2-(2-phenylethyl)-chromone (1).

Chemical Phenomena↗
PubMed1990

A family with Fabry's disease. Ocular manifestations and transmission electron microscopic examination of a skin lesion biopsy.

A family with Fabry's disease including 2 hemizygotes and 3 heterozygotes is reported. The ocular manifestations include tortuosity of conjunctival vessels, Fabry's deposits underlying the anterior capsule of the lens and the whorl-like corneal dystrophy. Foam cells or mulberry cells in the urinary sediment and varying numbers of high electron-dense inclusions in the cytoplasm of endothelial cells in skin lesions are also important in diagnosing this disease. The concentrations of lipid peroxide in the sera of 2 hemizygotes in this report were higher than normal, possibly due to the patients weak ability of anti-oxygenation and malfunction of cells whose plasma membranes are easily attacked by free oxygen radicals. The biochemical and pathological changes, diagnosis, treatment, genetics and prevention of the disease are discussed.

Adult↗
PubMed1990

[Chemical constituents of Armillaria mellea mycelium. VI. Isolation and structure of armillaripin].

A new protoilludane sesquiterpenoid aromatic ester, named armillaripin, C24H30O6, mp 202-204 degrees C, [alpha]D15 + 130 degrees (c 0.055, CHCl3), was isolated from the petroleum ether extract of the artificially cultured mycelium of Armillaria mellea (Vahl. ex Fr.) Quel. (Tricolometaceae) by silica gel chromatography. On the basis of spectral (UV, IR, 1HNMR 13CNMR and MS) analysis its structure was deduced as I and confirmed by single-crystal X-ray analysis.

Agaricales↗
PubMed1990

[Studies on the chemical constituents of Armillaria mellea mycelium. V. Isolation and characterization of armillarilin and armillarinin].

Two new protoilludane sesquiterpenoid aromatic esters, armillarilin C24H30O7, mp 179-180 degrees C, [alpha]D14 + 162 (c 0.97 CHC1(3] and armillarinin C24H29O7 C1, mp 152-155 degrees C, [alpha]D17 + 153.6, (c 0.09, CHC1(3], have been isolated from the artifically cultured mycelium of Armillaria mellea (Vahl. ex Fr.) Quel (Tricholometaceae). On the basis of spectral (UV, IR, 1HNMR, 13CNMR and MS) analysis their structures were identified as I and II, respectively.

Agaricales↗
PubMed1989

Steroid anesthetics and naturally occurring analogs modulate the gamma-aminobutyric acid receptor complex at a site distinct from barbiturates.

The steroid anesthetic alphaxalone and a series of naturally occurring analogs were compared in potency and efficacy with each other and the hypnotic barbiturate pentobarbital for interaction with gamma-aminobutyric acid (GABA) receptors:binding sites in rat brain membranes and functional activity in 36Cl- flux measurements with rat hippocampal slices. The steroids enhanced [3H]muscimol binding to GABA receptor sites, enhanced [3H] flunitrazepam binding to benzodiazepine receptors and inhibited [35S]t-butyl bicyclophosphorothionate binding to picrotoxin/convulsant binding sites on the GABA receptor-chloride channel complex. The same steroids that were active in modulating the binding of ligands to the various receptor sites on the GABA receptor complex at micromolar concentrations enhanced muscimol-stimulated 36Cl- flux in rat hippocampal slices. The steroids, like the barbiturates, increased the maximal response to muscimol but produced little or no potentiation of basal 36Cl- flux in the absence of GABA agonist. Although the effects of steroids and barbiturates were similar, separate sites of action were demonstrated conclusively by the observation that the two classes of compounds, when included together, gave additive or synergistic effects on binding, as well as on 36Cl- flux in the absence of GABA agonist. Structure-activity studies showed that the synthetic steroid anesthetic alphaxalone was the most potent compound tested, followed by the naturally occurring steroids tetrahydro-deoxycorticosterone, allo-tetrahydrocorticosterone, cis-androsterone and 5 alpha-androstan-17 beta-ol-3-one. The ability of several naturally occurring steroids to enhance GABA-mediated inhibition in the brain suggests the possibility of an endogenous steroid modulator of neuronal function.

Anesthetics↗
PubMed1989

[Studies on the chemical constituents of Aquilaria sinensis(Lour.) Gilg. IV. Isolation and characterization of 2-(2-phenylethyl)chromone derivatives].

Six chromone derivatives were isolated from the ether soluble fraction of the alcoholic extract of Aquilaria sinensis(Lour.) Gilg. (Thymeleaceae) by silica gel chromatography. On the basis of spectrometric data (UV, IR, 1HNMR and 13CNMR as well as MS) and chemical synthesis one of them was found to be a new chromone, 6-hydroxy-2-[2-(4'-methoxylphenyl)ethyl]chromone(VI) and the other five known chromones are 2-(2-phenylethyl)chromone(I), 6-methoxy-2-(2-phenylethyl)chromone (II), 6.7-dimethoxy-2-(2-phenylethyl)chromone(III), 6-methoxy-2[2-(3'-methoxyphenyl)ethyl]chromone(IV) and 6-hydroxy-2-(2-phenylethyl) chromone(V). These compounds were obtained for the first time from this plant.

Chemical Phenomena↗