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Biomedical subjects

G Y Wang

Publications and source records attributed to G Y Wang.

At least 19 recordsLinked to original sources
PubMed2006

In-plane ferromagnetism in charge-ordering Na0.55CoO2.

The magnetic and transport properties are systematically studied on the single crystal Na(0.55)CoO2 with the resistivity divergence below 50 K. A weak ferromagnetic ordering is observed in susceptibility below 20 K with the magnetic field parallel to the Co-O plane, while no such ferromagnetic ordering is observed with the field perpendicular to the Co-O plane. It gives evidence for the existence of in-plane ferromagnetism below 20 K. The observed magnetoresistance of 30% at the field of 6 T at low temperatures indicates an unexpectedly strong spin-charge coupling in the triangle lattice NaxCoO2 system.

Journal Article↗
PubMed2005

Indoor physical education measured by heart rate monitor. A case study in Portugal.

AIM: Reports indicated that children are spending too much time being physically inactive during physical education classes and many school physical education programs are not meeting the recommendation. The purpose of this study was to investigate the physical activity levels in Portuguese indoor physical education classes. METHODS: The physical activity levels of 28 Portuguese 7th grade children were assessed by heart rate monitor during their indoor physical education classes. RESULTS: The study showed that much physical education class time had been wasted, and less than 70% of physical education class time had actually been used in classes. On average, 14.4 minutes of 45-min physical education classes and 27.9 min of 90-min physical education classes had been spent in MVPA with children's heart rates above 139 bpm; 6.7 min of 45-min physical education classes and 15.7 min of 90-min physical education classes had been spent in VPA with children's heart rates above 159 bpm. Children engaged in more MVPA, VPA, and continuous bouts of physical activity in 90-min physical education classes than those of 45-min physical education classes. There were no significant differences in activity levels between genders in co-educational indoor physical education classes. CONCLUSIONS: This indoor PE class study supports the results that children are less active during school physical education classes. Both the quantity and the quality of school physical education needs to improve to encourage children to engage in a substantial amount of physical activity both inside and outside school.

Adolescent↗
PubMed2004

Effects of Se and Zn supplementation on the antagonism against Pb and Cd in vegetables.

The antagonistic effects of supplementation of Zn and Se to the soil on vegetables were studied in this work. In the pot experiment, Se (Se4+) and Zn (Zn2+) were applied, respectively, to the soil, in which the Chinese cabbage (Brassica rapa) and the lettuce (Lactuca sativa L.) were planted. As a result, Se and Zn were enriched evidently in the two vegetables. The contents of Pb and Cd in the two vegetables were decreased markedly while contents of some healthy mineral elements, like Mn and Mg, were increased to some extent when Se and Zn were applied. The antagonism of Se and Zn against Pb and Cd in plants was suggested. The farmland experiment on the lettuce was conducted to explore further the effect of supplementation of Zn and Se under the actual field conditions. Result came out to be that the enrichment of Zn and Se restrained the accumulation of Pb and Cd in the lettuce remarkably, as well as enhanced the absorption of some other nutritional elements, like Fe, Mn, Cu, Ca and Mg. Therefore, application of Se and Zn was proved to be an effective and feasible method to improve trace elements nutrition in the vegetables.

Brassica↗
PubMed2003

Ancient traditional Chinese medicine in burn treatment: a historical review.

Burn treatment in traditional Chinese medicine (TCM) has a long and remarkable history. This article provides a review of it's philosophy and knowledge, basic principles and treatment strategies as well as their modifications during 1300 years of medical development. The specific features presented are still influencing modern traditional Chinese medicine practitioners as well as modern Chinese burn treatment with considerable benefit for the treatment of burn victims.

Burns↗
PubMed2001

Unique functional properties of on and off pathways in the developing mammalian retina.

In the mature retina, the dendrites of On and Off ganglion cells are segregated into separate sublaminas of the inner plexiform layer, but early in development these processes are multistratified, ramifying more widely within this synaptic layer. The dendritic pattern exhibited by immature ganglion cells suggests that there may be a functional convergence of On and Off pathways in the developing retina, but previous studies have provided evidence against this. Here we demonstrate by patch-clamp recordings and dye filling that ganglion cells with multistratified dendrites respond to the onset, as well as the offset, of light. We further show that, in the dark-adapted retina, the glutamate analog 2-amino-4-phosphonobutric acid abolishes On and Off discharges in ganglion cells with multistratified dendrites. In contrast, in cells with stratified dendrites, this drug selectively blocks On responses. These findings provide evidence for unique functional attributes of On and Off pathways in the developing retina. The properties of immature ganglion cells documented here have important implications for the roles ascribed to neuronal activity in refining connections during the early development of the visual system.

Action Potentials↗
PubMed2001

Cardiac effects of the extract and active components of radix stephaniae tetrandrae. II. Myocardial infarct, arrhythmias, coronary arterial flow and heart rate in the isolated perfused rat heart.

The primary purpose of the present study was to compare the cardioprotective effects of the extract from radix stephaniae tetrandrae (RST) and its individual compounds, tetrandrine (Tet) and fanchinoline (Fan). Secondly, we also compared the cardiac effects of the individual compounds and the RST extract with those of verapamil, a classical Ca2+ channel blocker. The Langendorff isolated perfused rat heart preparation was used. Regional ischaemia and reperfusion was employed to induce myocardial infarct and arrhythmia. Infarct, arrhythmia, heart rate and coronary artery flow were determined in hearts treated with vehicle, RST extract, Tet, Fan, or verapamil. It was found that RST extract, of which only 9% was Tet, and Tet alone produced equally potent ameliorating effects on arrhythmia and infarct induced by ischaemia and reperfusion without further inhibiting ischaemia-reduced heart rate and coronary artery flow. Fan had no effects on arrhythmia and infarct induced by ischaemia and reperfusion; but it induced S-T segment elevation and further reduced heart rate and coronary artery flow during ischaemia. Verapamil also ameliorated the effects of ischaemia and reperfusion on arrhythmia and infarct. It should be noted that 1 microM verapamil, that produced comparable effects on infarct and arrhythmia to the RST extract and Tet, further inhibited heart rate during ischaemia. The results indicate that the RST extract produces equally potent cardioprotective and anti-arrhythmic effects as Tet alone. Both RST extract and Tet may be better choices for the treatment of arrhythmia and infarct induced by myocardial ischaemia and reperfusion than the classical Ca2+ channel blocker, verapamil as they do not further reduce heart rate during ischaemia.

Alkaloids↗
PubMed2001

Kappa- but not delta-opioid receptors mediate effects of ischemic preconditioning on both infarct and arrhythmia in rats.

Two series of experiments were performed in the isolated perfused rat heart to determine the role of kappa- and delta-opioid receptors (OR) in cardioprotection of ischemic preconditioning (IP). In the first series of experiments, it was found that IP with two cycles of 5-min regional ischemia followed by 5-min reperfusion each reduced infarct size induced by 30-min ischemia, and the ameliorating effect of IP on infarct was attenuated with blockade of either 5 x 10(-6) mol/l nor-binaltorphimine (nor-BNI), a selective kappa-OR antagonist, or 5 x 10(-6) mol/l naltrindole (NTD), a selective delta-OR antagonist. The second series showed that U50,488H, a selective kappa-OR agonist, or D-Ala(2)-D-leu(5)-enkephalin (DADLE), a selective delta-OR agonist, dose dependently reduced the infarct size induced by ischemia, which mimicked the effects of IP. The effect of 10(-5) mol/l U50,488H on infarct was significantly attenuated by blockade of protein kinase C (PKC) with specific PKC inhibitors, 5 x 10(-6) mol/l chelerythrine or 8 x 10(-7) mol/l calphostin C, as well as by blockade of ATP-sensitive K(+) (K(ATP)) channels with blockers of the channel, 10(-5) mol/l glibenclamide or 10(-4) mol/l 5-hydroxydecanoate. IP also reduced arrhythmia induced by ischemia. Nor-BNI, but not NTD, attenuated, while U50,488H, but not DADLE, mimicked the antiarrhythmic action of IP. In conclusion, the present study has provided first evidence that kappa-OR mediates the ameliorating effects of IP on infarct and arrhythmia induced by ischemia, whereas delta-OR mediates the effects only on infarct. Both PKC and K(ATP) channels mediate the effect of activation of kappa-OR on infarct.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed2001

Inducible HSP70 mediates delayed cardioprotection via U-50488H pretreatment in rat ventricular myocytes.

To test the hypothesis that heat-shock proteins (HSPs) mediate delayed cardioprotection of prior kappa-opioid receptor (kappa-OR) stimulation, we first correlated cellular injury and viability with the expression of HSP70s in isolated rat ventricular myocytes subjected to prior kappa-OR stimulation with the selective agonist trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide (U-50488H) and delayed lethal simulated ischemia (LSI). Cell injury and viability were indicated by lactate dehydrogenase release and trypan blue exclusion, respectively. The reduced injury and increased viability after pretreatment with U-50488H were concentration dependent and correlated directly with the expression of both stress-inducible (HSP70) and constitutive (HSC70) proteins. The effects mimic those with metabolic inhibition preconditioning (MIP). The cardioprotection against LSI by pretreatment with U-50488H and MIP was abolished and antagonized, respectively, via blockade of the kappa-OR by its selective antagonist, nor-binaltorphimine. We also found that blockade of the production of HSP70 but not HSC70 blocked the inhibitory effect of pretreatment with U-50488H on injury and viability. These observations provide evidence that stress-inducible HSP70 mediates delayed cardioprotection of prior kappa-OR stimulation.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed2001

Protein kinase C-epsilon is a trigger of delayed cardioprotection against myocardial ischemia of kappa-opioid receptor stimulation in rat ventricular myocytes.

Kappa-opioid receptor (OR) stimulation with a selective agonist, U50,488H (U50), known to mediate the delayed cardioprotection of metabolic inhibition preconditioning (MIP) against cell injury/death in rat ventricular myocytes, has been shown to act via protein kinase C (PKC). We attempted to identify the PKC isoform(s) that is activated, thus triggering delayed cardioprotection of MIP and pretreatment with 10 microM U50 (U50 pretreatment, UP). Release of lactate dehydrogenase and exclusion of trypan blue by isolated rat ventricular myocytes were used as indices of cell injury and death, respectively. Both MIP and UP induced translocation of PKC-epsilon, but not other PKC isoforms, -alpha and -delta, from cytosolic to membrane fractions. This was accompanied by reductions in cell injury/death induced by lethal simulated ischemia. The effects of MIP and UP were attenuated and abolished by 1 microM nor-binaltorphimine, a selective kappa-OR antagonist, administered before and during preconditioning/pretreatment, respectively. The effects were mimicked by 10 nM phorbol-12-myristate-13-acetate, a PKC activator, but attenuated by 5 microM chelerythrine, a PKC inhibitor. More importantly, 0.1 microM epsilonV1-2, a selective PKC-epsilon inhibitor administered before and during MIP/UP, also attenuated the effects of both treatments on cell injury/death and translocation of PKC-epsilon. On the other hand, 5 microM rottlerin, a selective PKC-delta inhibitor, did not alter the effects of either treatment on injury/death. The results indicate that both MIP and UP activate PKC-epsilon, leading to delayed cardioprotection in rat ventricular myocytes.

Acetophenones↗
PubMed2000

Affinity purification and characterization of a cutinase from the fungal plant pathogen Monilinia fructicola (Wint.) honey.

Trifluoromethyl ketones (TFK) are potent inhibitors of a variety of serine hydrolases. The TFK inhibitor, 3-(4-mercaptobutylthio)-1,1,1-trifluoro-2-propanone (MBTFP), was found to competitively inhibit cutinase activity (I50 = 9.4 x 10(-3)) from the fungal plant pathogen Monilinia fructicola and to serve as an effective affinity ligand for the purification of cutinases from culture filtrates. The TFK inhibitors, 3-n-octylthio-1,1,1-trifluoro-2-propanone (OTFP) and 3-n-pentylthio-1,1,1-trifluoro-2-propanone (PTFP), also inhibited cutinase activity with I50 values of 1.6 x 10(-6) and 2.3 x 10(-4) M, respectively. Buffer containing OTFP was the strongest eluant for cutinases of M. fructicola and provided the best purification factor and yield, although buffers containing OTFP, detergent, and salt were found to be effective for eluting cutinases bound to MBTFP-Sepharose. Buffer containing 0.5% Triton X-100 also selectively eluted cutinases from the affinity column. Two-dimensional electrophoretic analysis by SDS-PAGE and isoelectric focusing of the affinity-purified cutinase fraction indicated activity associated with proteins of pI 8.2 and molecular masses of approximately 18.6 and 20.8 kDa. These proteins hydrolyzed [3H]cutin and artificial substrates such as p-nitrophenylbutyrate and related esters, typical of other cutinases, but differ from previously characterized cutinases in molecular mass. The two low-molecular-weight proteins resolved by 2-D gel electrophoresis were subjected to in-gel digestion with Lys-C and the resulting peptide fragments were separated by Microbore-HPLC. The amino acid sequences of several internal peptide fragments had high homology with cutinase sequences from other fungi, particularly the plant pathogen Botrytis cinerea. Our study illustrates the potential of TFK ligands for the affinity purification of cutinases and indicates that the cutinases from M. fructicola have novel features warranting further study.

Acetone↗
PubMed2000

Novel natural products from soil DNA libraries in a streptomycete host.

As a route to accessing the potential chemical diversity of uncultivable microbes from the soil, combinatorial biosynthetic libraries were constructed by cloning large fragments of DNA isolated from soil into a Streptomyces lividans host. Four novel compounds, terragines A (1), B (2), C (3), and D (4), were isolated from recombinant 436-s4-5b1, and another novel compound, terragine E (5), was isolated from 446-s3-102g1. The structures were determined by a combination of spectroscopic techniques, primarily 2D NMR.

Amides↗
PubMed2000

Molecular cloning and characterization of functional domains of a human testis-specific isoform of calpastatin.

Human serum containing sperm-agglutinating antibodies was used to screen a testis cDNA expression library to identify the cognate antigens that may be responsible for this biological effect. The longest positive phage clone (1.9 kb) was sequenced and found to be a testis-specific isoform of calpastatin (tCAST). The testis-specific segment of tCAST is encoded by a single exon within intron 14 of the calpastatin gene. A unique protein isoform is produced that differs in domain structure from the somatic calpastatins (sCAST). Human sCAST most commonly has an N-terminal domain L plus the four functional calpain inhibitory domains. Human tCAST consists of a 40-amino-acid N-terminal T domain plus a part of domain II and all of domains III and IV from the somatic isoform. Our data show that the T domain can target cytosolic localization and membrane association of tCAST, whereas domain I of sCAST exhibits a nuclear localization function. Calpastatin is the endogenous inhibitor of calpain. The calpain/calpastatin system is involved in membrane fusion events for several cell types, and calpain has been localized to the sperm acrosome. We detected tCAST in human sperm and testes extracts by Western blotting with specific antisera. These observations suggest that tCAST may modulate calpain in the calcium-mediated acrosome reaction that is required for fertilization.

Amino Acid Sequence↗
PubMed2000

Enhanced production of microbial metabolites in the presence of dimethyl sulfoxide.

Bacterial strains grown in the presence of low concentrations of dimethyl sulfoxide (DMSO) exhibit significant qualitative and quantitative alterations in the production of secondary metabolites. This effect was confirmed for a variety of biosynthetic families, including chloramphenicol (chorismate), thiostrepton (peptide) and tetracenomycin (polyketide), and for natural and recombinant strains of streptomycetes; a similar effect was seen with antibiotic-producing bacilli such as B. circulans. Increase in antibiotic production was not the result of a change in the growth rate of these organisms, since yields of biomass were similar in media with and without DMSO (up to 3%). We suggest that the addition of compounds such as DMSO provides a means of examining the full biosynthetic potential of microbes and might be used to promote secondary metabolite production. The mode of action of DMSO is not known, but in the cases studied it may act at the level of translation.

Anti-Bacterial Agents↗
PubMed1999

Differential effects of apamin- and charybdotoxin-sensitive K+ conductances on spontaneous discharge patterns of developing retinal ganglion cells.

The spontaneous discharge patterns of developing retinal ganglion cells are thought to play a crucial role in the refinement of early retinofugal projections. To investigate the contributions of intrinsic membrane properties to the spontaneous activity of developing ganglion cells, we assessed the effects of blocking large and small calcium-activated potassium conductances on the temporal pattern of such discharges by means of patch-clamp recordings from the intact retina of developing ferrets. Application of apamin and charybdotoxin (CTX), which selectively block the small and large calcium-activated potassium channels, respectively, resulted in significant changes in spontaneous firings. In cells recorded from the oldest animals [postnatal day 30 (P30)-P45], which manifested relatively sustained discharge patterns, application of either blocker induced bursting activity. With CTX the bursts were highly periodic, short in duration, and of high frequency. In contrast, with apamin the interburst intervals were longer, less regular, and lower in overall spike frequency. These differences between the effects of the two blockers on spontaneous activity were documented by spectral analysis of discharge patterns. Filling cells from which recordings were made with Lucifer yellow revealed that these effects were obtained in all three morphological classes of cells: alpha, beta, and gamma. These findings provide the first evidence that apamin- and CTX-sensitive K+ conductances can have differential effects on the spontaneous discharge patterns of retinal ganglion cells. Remarkably, the bursts of activity obtained after apamin application in more mature neurons appeared very similar to the spontaneous bursting patterns observed in developing neurons. These findings suggest that the maturation of calcium-activated potassium channels, particularly the apamin-sensitive conductance, may contribute to the changes in spontaneous firings exhibited by retinal ganglion cells during the course of normal development.

Action Potentials↗
PubMed1999

Variant antibody identification by peptide mapping.

During development of CGP56901, a monoclonal antibody (MAb) specific for a unique epitope on human IgE, the protein A-purified IgG from one of the candidate production cell lines, showed an additional minor heavy chain (H-chain) band with a molecular weight slightly lower than that of the principal H-chain band on SDS-PAGE. The N-terminal amino acid sequence of this minor H-chain species indicated that at least the first 30 amino acids were identical to those of the antibody light-chain (L-chain) variable domain. More detailed studies using peptide mapping and amino acid sequencing analysis confirmed a crossover event between the V genes of the antibody. The position is between Arg108 of the L chain and Ala124 of the H chain. This crossover resulted in a variant H chain, which had 16 fewer amino acid residues than the normal CGP56901 H chain. These results show that peptide mapping is a useful "first-line" analytical tool in the characterization of the quality of the monoclonal antibody.

Amino Acid Sequence↗
PubMed1999

Effects of storage and cooking on the iodine content in iodized salt and study on monitoring iodine content in iodized salt.

In order to ensure that the intake of iodine from iodized salt is adequate, the effects of cooking, storage and iodination on iodine content in iodized salt have been studied. For monitoring the analytical performance, a quality control examination was also undertaken. The loss of iodine was greater when salt was stored in plastic bag than in glass bottle. The loss was greater in fortified salt stored at 37 degrees C and under 76% humidity than in that at 20-25 degrees C and under lower humidity. The retention of iodine varied with the kind of foods and also was influenced by the water content of cooked food. In general, the retention of iodine during cooking varied considerably (from 36.6% to 86.1%). The iodine concentration in salts varied greater from 3.0 to 100.3 mg/kg in salt for markets, and from 0 to 90.0 mg/kg in salts for households. 48.3% of samples from markets were found to be in compliance with national standards (30-50 mg/kg), and 72.0% of samples from households were in compliance with national standard (20-50 mg/kg). Analytical data collected from 8 of the cooperative laboratories for an analytical reference material showed a 95% confidence interval of the population mean for both precision and accuracy, falling within X +/- 2SD and passing quality control examination.

Food Preservation↗
PubMed1999

[Studies of transgene segregation and integration in maize].

The segregation, integration and stability of the transgene-Bt (Bacillus thuringensis) in eight transformants created by three ways of transformation were studied by means of PCR (Polymerase chain reaction) and DNA molecular hybridization. The results are as follows: (1) The transgene-Bt in most of the progenies of the transformants showed simple Mendelian segregation. Although some deviation from Mendelian fashion existed in the early generations, the normal Mendelian segregation would be found after R3 generations and the transgene could fix in the populations. (2) The integration patterns of the transgene varied to the some extent in the different transformants, but they were characterized by either smaller band and copy numbers or cascade integration or closely linked integration in all transformants. (3) Changes of the Southern land pattern were found in some families of some transformants, especially, in the two families of Ding 4R5.

Blotting, Southern↗