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Biomedical subjects

D Yang

Publications and source records attributed to D Yang.

At least 235 records · Page 13Linked to original sources
PubMed1999

[Chemical composition of essential oil from leaves of litsea cubeba and its antifungal activities].

The 24 chemical constituents of the essential oil extracted from the leaves of Litsea cubeba have been identified by means of GC-MS technique. Among which, alpha-cis-ocimene(25.11%), 3,7-dimethyl-1,6-octadien-3-ol(16.85%) and n-transnerolidol (13.89%) were the principal components. In vitro this oil had a manifest antifungal activities with MIC between 0.03-0.4 microliter/ml for utilized pathogenic fungi and 1.0-2.0 microliters/ml for moulds.

Acyclic Monoterpenes↗
PubMed1999

[Habitats and present situations of 13 rare precious medicinal materials in Funiu mountains].

The living resources are very abound in the Funiu mountains area because of its special geographical position and climate, and there are also many rare precious living beings and Chinese medicinal herbs, for example, Taxus mairei, Ginkgo biloba, Gastrodia elata, Dendrobium huashanense, Physochlaina infunbularis, Cypripedium japonicum, Dysosma versipellis, Moschus moschiferus, Megalobatrachus davidanus, Succinum, etc, and conscious protection and rational development is an urgent task.

Animals↗
PubMed1999

[Chemical constituents of the essential oil from the fruits of Lindera glauca and its antifungal activities].

The chemical constituents of the two essential oils extracted from the fruits of Lindera glauca by hydrodistillation and petroleum ether have been studied by means of GC-MS. Among which, 32 kinds of constituents were identified in distilling oil and 22 kinds in solvent oil. The main components in distilling oil were n-carpric acid (25.39%), germacrene A (10.71%), n-dodecanole acid (10.08%), epishyobunol acetate (7.29%) and caryophyllene oxide (5.44%), and in solvent oil were camphene (17.55%), 3,6,6-trimethyl-2-norpinene (16.85%), capric acid, ethyl ester (13.61%), eucalyptol (8.10%), and alpha-cis-ocimene (7.38%), In vitro the distilling oil exhibited more manifest antifungal properties than the solvent oil with MIC between 0.03-0.5 ml/L for pathogenic fungi species and 1.0-1.5 ml/L for moulds. Almost having not contained the sesquiterpenoids and their derivatives in the solvent oil maybe were a reason of poor inhibitory.

Antifungal Agents↗
PubMed1999

[GC-MS analysis and inhibitory activity of the essential oil extracted from the leaves of Lindera communis].

The essential oil isolated from the dried leaves of Lindera communis was analyzed by means of gas chromatography-mass(GC-MS) technique, the structures of 23 chemical components were identified from it in total, among these, (-)-spathulenol(relative content 22.50%), endo-1,3,3-trimethyl-2-norbornanol, acetate (10.06%), caryophyllene oxide (6.74%) and germacrene B(6.71%) were the main constituents. And also the oil in vitro exhibited manifest antifungal and antibacterial activities against 4 fungi pathogen species and 4 bacterial species with MIC between 0.08-0.8 ml/l.

Anti-Bacterial Agents↗
PubMed1999

[Minimally invasive treatment in early glottic cancer and vocal cord dysplasia].

OBJECTIVE: To investigate the pathologic and clinical diagnosis of early stage glottic carcinoma and the vocal cord dysplasia and the results of the minimally invasive treatment. METHODS: Thirty-two cases of early glottic cancer (T1N0M0) and 20 cases of vocal dysplasia were treated with mucous stripping and minimally invasive cordectomy under the micro-suspension laryngoscope. The pathomorphology was observed with continuous sections. RESULTS: After 3-4 years follow-up, 26 cases of early glottic cancer remained tumor free, 3 cases relapsed and 2 cases received the re-stripping operation. twenty cases of vocal cord dysplasia were classified as: leucoplakia of vocal cord, mild atypical hyperplasia, moderate atypical hyperplasia and advanced hyperplasia. None of them had malignant change after 3 years follow-up. CONCLUSION: The laryngeal micro-operation under the micro-suspension laryngoscope is an effective and safe cure procedure, it provides a definite diagnostic method for the early stage glottic carcinoma and the vocal cord dysplasia.

Combined Modality Therapy↗
PubMed1999

[Study on the molar absorption coefficients of Bi(III)-thiocyanate complexes in UV spectrum].

The absorption spectra of bismuth(II)-thiocyanate in the Tween-80-H2O solution were studied in this paper, in which the maximum wavelength lambdamax = 335 nm and the molar extinction coefficient epsilon335 = 2.61 x 10(4), similar to those of complexes of bismuth with PAR or azoarsenic(III), epsilon610 = 2.70 x 10(4). A new tribasic complex was found and used to explain that bismuth(III)-thiocyanate is a sensitive colour reaction in the Tween-80-H2O solution.

English Abstract↗
PubMed1999

[The thermodynamic molar absorptivity of coordination color reaction of indium(III) with 4,5-dihydroxybenzene-1,3-disufornic acid].

The thermodynamic molar absorptivity of complex formed by 1:1 coordination color reaction of tiron with highly charged cation In3+ has been measured spectrophotometrically at 20.0+/-0.1 degrees C, using NaClO4 as supporting electrolyte. The influence of å on linear relation between molar absorptivity and ionic strength has been investigated. At å = 6.5, the thermodynamic molar absorptivity lg epsilon(o) was found to be 3.69.

English Abstract↗
PubMed1998

Subdomain chimeras of hepatic lipase and lipoprotein lipase. Localization of heparin and cofactor binding.

To specify and localize carboxyl-terminal domain functions of human hepatic lipase (HL) and human lipoprotein lipase (LPL), two subdomain chimeras were created in which portions of the carboxyl-terminal domain were exchanged between the two lipases. The first chimera (HL-LPLC1) was composed of residues 1-344 of human HL, residues 331-388 of human LPL, and residues 415-476 of human HL. The second chimera (HL-LPLC2) consisted of just two segments, residues 1-414 of human HL and residues 389-448 of human LPL. These chimeric constructs effectively divided the HL C-terminal domain into halves, with corresponding LPL sequences either in the first or second portion of that domain. Both chimeras were lipolytically active and hydrolyzed triolein emulsions to a similar extent compared with native HL and LPL. Heparin-Sepharose chromatography demonstrated that HL-LPLC1 and HL-LPLC2 eluted at 0.80 and 1.3 M NaCl, respectively, elution positions that corresponded to native HL and LPL. Hence, substitution of LPL sequences into the HL carboxyl-terminal domain resulted in the production of functional lipases, but with distinct heparin binding properties. In addition, HL-LPLC2 trioleinase activity was responsive to apoC-II activation, although the -fold stimulation was less than that observed with native LPL. Moreover, an apoC-II fragment (residues 44-79) was specifically cross-linked to LPL and HL-LPLC2, but not to HL or HL-LPLC1. Finally, both chimeras hydrolyzed phospholipid with a specific activity similar to that of HL, which was unaffected by the presence of apoC-II. These findings indicated that in addition to a region found within the amino-terminal domain of LPL, apoC-II also interacted with the last half of the carboxyl-terminal domain (residues 389-448) to achieve maximal lipolytic activation. In addition, the relative heparin affinity of HL and LPL was determined by the final 60 carboxyl-terminal residues of each enzyme.

Apolipoprotein C-II↗
PubMed1998

Blockade of bepridil on IA and IK in acutely isolated hippocampal CA1 neurons.

The effects of bepridil, an antianginal agent with antiarrhythmic action, on voltage-dependent K+ currents in the CA1 pyramidal neurons acutely isolated from rat hippocampus were studied by means of whole-cell patch clamp techniques. Current recordings were made in the presence of TTX to block Na+ current. Depolarizing test pulses activated two components of outward K+ currents: a rapidly activating and inactivating component, IA; and a delayed component, IK. Results showed that bepridil reduced the amplitude of IA and IK, and exerted its inhibitory action in time- and dose-dependent manner. Half-blocking concentrations (IC50) of bepridil on IA and IK were 17.8 microM and 1.7 microM, respectively. 10 microM bepridil suppressed IA and IK by 46.7% and 77.1% at +30 mV of depolarization, respectively. When IK was activated nearly uncontaminated with IA by holding at -50 mV, 10 microM bepridil inhibited IK by 71.6% at +30 mV of depolarization; 10 microM bepridil positively shifted the voltage-dependent of activation curves of IA and IK 12.1 mV and 28.7 mV, respectively. These results suggested that blockade on K+ currents by bepridil is preferential for IK, and contributes to the protection brain against ischemic damage.

Animals↗
PubMed1998

LIGHT, a novel ligand for lymphotoxin beta receptor and TR2/HVEM induces apoptosis and suppresses in vivo tumor formation via gene transfer.

LIGHT is a new member of tumor necrosis factor (TNF) cytokine family derived from an activated T cell cDNA library. LIGHT mRNA is highly expressed in splenocytes, activated PBL, CD8(+) tumor infiltrating lymphocytes, granulocytes, and monocytes but not in the thymus and the tumor cells examined. Introduction of LIGHT cDNA into MDA-MB-231 human breast carcinoma caused complete tumor suppression in vivo. Histological examination showed marked neutrophil infiltration and necrosis in LIGHT expressing but not in the parental or the Neo-transfected MDA-MB-231 tumors. Interferon gamma (IFNgamma) dramatically enhances LIGHT-mediated apoptosis. LIGHT protein triggers apoptosis of various tumor cells expressing both lymphotoxin beta receptor (LTbetaR) and TR2/HVEM receptors, and its cytotoxicity can be blocked specifically by addition of a LTbetaR-Fc or a TR2/HVEM-Fc fusion protein. However, LIGHT was not cytolytic to the tumor cells that express only the LTbetaR or the TR2/HVEM or hematopoietic cells examined that express only the TR2/HVEM, such as PBL, Jurkat cells, or CD8(+) TIL cells. In contrast, treatment of the activated PBL with LIGHT resulted in release of IFNgamma. Our data suggest that LIGHT triggers distinct biological responses based on the expression patterns of its receptors on the target cells. Thus, LIGHT may play a role in the immune modulation and have a potential value in cancer therapy.

Apoptosis↗
PubMed1998

Proteolytic processing of rubella virus nonstructural proteins.

The genomic RNA of rubella virus contains two long open reading frames (ORF), a 5'-proximal ORF that codes for the nonstructural proteins and a 3'-proximal ORF that encodes the structural proteins. The cDNA encoding the nonstructural protein ORF of the wild-type M33 strain of rubella virus has been obtained and sequenced. Comparison between the nonstructural proteins of the M33 and Therien strains of rubella virus revealed a 98% homology in nucleotide sequence and 98.1% in deduced amino acid sequence. To examine the processing of rubella virus nonstructural protein, the complete nonstructural protein ORF was expressed in BHK cells using a pSFV expression vector. Three nonstructural protein products (p200, p150, and p90) with molecular weights of 200, 150, and 90 kDa were identified using antisera raised against synthetic peptides corresponding to regions of the nonstructural proteins. p200 is the polyprotein precursor, while p150 and p90 are the cleavage products. Site-directed mutagenesis of the Cys-1151 residue (one of the catalytic dyad residues of the viral protease) and of the Gly-1300 residue (the viral protease cleavage site) abrogated protease activity and p200 precursor cleavage, respectively. Coexpression of mutant constructs in BHK cells indicated that rubella virus protease can function both in cis and in trans.

Animals↗
PubMed1998

Requirements for the adaptor protein role of dihydrolipoyl acetyltransferase in the up-regulated function of the pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase.

The dihydrolipoyl acetyltransferase (E2 component) is a 60-mer assembled via its COOH-terminal domain with exterior E1-binding domain and two lipoyl domains (L2 then L1) sequentially connected by mobile linker regions. E2 facilitates markedly enhanced function of the pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase phosphatase (PDP). Human E2 structures were prepared with only one lipoyl domain (L1 or L2) or with alanines substituted at the sites of lipoylation (Lys-46 in L1 or Lys-173 in L2). The L2 domain and its lipoyl group were shown to be essential for markedly enhanced PDP function and were required for greatly up-regulated PDK function. The complete absence of the L1 domain reduced the enhancements of both of these activities but not the maximal effector-stimulated PDK activity through acetylation of L2. With nonlipoylated L2 present, lipoylated L1 supported a lesser enhancement in PDK function with significant stimulation upon acetylation of L1. Prevention of L1 lipoylation in K46AE2 removed this competitive L1 role and enhanced L2-facilitated PDK activity beyond that of native E2 when PDK activity was measured in the absence or in the presence of stimulatory effectors. Thus, the E2-L2 domain has a paramount role in facilitating enhanced PDK and PDP function but inclusion of E2-L1 domain, even in a noninteracting (nonlipoylated) form, contributes to the marked elevation of these activities.

Acetyltransferases↗
PubMed1998

Amyloid protein precursor stimulates excitatory amino acid transport. Implications for roles in neuroprotection and pathogenesis.

Excitatory neurotransmitters such as glutamate are required for the normal functioning of the central nervous system but can trigger excitotoxic neuronal injury if allowed to accumulate to abnormally high levels. Their extracellular levels are controlled primarily by transmitter uptake into astrocytes. Here, we demonstrate that the amyloid protein precursor may participate in the regulation of this important process. The amyloid protein precursor has been well conserved through evolution, and a number of studies indicate that it may function as an endogenous excitoprotectant. However, the mechanisms underlying this neuroprotective capacity remain largely unknown. At moderate levels of expression, human amyloid protein precursors increased glutamate/aspartate uptake in brains of transgenic mice, with the 751-amino acid isoform showing greater potency than the 695-amino acid isoform. Cerebral glutamate/aspartate transporter protein levels were higher in transgenic mice than in non-transgenic controls, whereas transporter mRNA levels were unchanged. Amyloid protein precursor-dependent stimulation of aspartate uptake by cultured primary astrocytes was associated with increases in protein kinase A and C activity and could be blocked by inhibitors of these kinases. The stimulation of astroglial excitatory amino acid transport by amyloid protein precursors could protect the brain against excitotoxicity and may play an important role in neurotransmission.

Amyloid beta-Protein Precursor↗
PubMed1998

Screening for overlapping bacterial artificial chromosome clones by PCR analysis with an arbitrary primer.

In this article, we used PCR analysis with arbitrary primers (AP-PCR) to screen for overlapping bacterial artificial chromosome (BAC) clones and assembly of contigs. A rice BAC library with three genome equivalents was used to prepare pooled BAC DNA. Twenty-two arbitrary primers were used to survey the pooled BAC DNAs and individual BAC DNAs. Each primer identified 1-10 loci, and the average was 4.4 loci. There were 1-5 overlapping clones in each locus, and the average was 2.5 clones. A total of 245 BAC clones were identified as overlapping by AP-PCR and the identities were confirmed by DNA-DNA hybridization. The 245 BAC clones were then assembled into 80 contigs and 17 single-clone loci. The results indicated that PCR analysis with arbitrary primers is a powerful tool in screening for overlapping BAC clones with high accuracy and efficiency. The use of AP-PCR analysis should speed up the construction of physical maps of the plant and animal genomes, as well as the rice genome.

Base Sequence↗