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Biomedical subjects

S Yue

Publications and source records attributed to S Yue.

At least 19 recordsLinked to original sources
PubMed2006

Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants.

The microstructure and its effect on the friction behavior of a medical grade wrought cobalt-chromium-molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed-packed (HCP) phase due to a strain-induced transformation (SIT) from the metastable face-centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics.

Chromium Alloys↗
PubMed2006

Mechanism of neuroprotective effect induced by QingKaiLing as an adjuvant drug in rabbits with E. coli bacterial meningitis.

OBJECTIVE: To explore the neuroprotective effects and underlying mechanism of QingKaiLing (QKL) as an adjuvant treatment for bacterial meningitis. METHOD: E. coli bacterial meningitis rabbits were treated with antibiotics (ampicillin) alone or in combination with QKL. The number of leukocytes and the concentration of protein in the cerebrospinal fluid (CSF) of rabbits were determined at 0, 16, and 26 hours after treatment. Brain water, sodium, potassium, and calcium contents were determined at the 26-hour time point. The level of matrix metalloproteinase-9 in the brain was also determined by Western blot. RESULT: The average number of leukocytes and the concentration of protein in CSF of the QKL adjuvant treatment group were reduced compared with the ampicillin alone group. Brain water, sodium, and calcium contents were reduced in the QKL adjuvant treatment group. The level of MMP-9 in brain tissue was also reduced in the QKL adjuvant treatment group. CONCLUSION: QKL adjuvant treatment alleviates the aggravated inflammatory reaction and partially protects brain tissue from antibiotic-induced injury. The mechanism of this neuroprotective effect of QKL may be due to decreased levels of Ca2+ and MMP-9 in the brain.

Acute Disease↗
PubMed2006

Nanofluidic channels fabrication and manipulation of DNA molecules.

Nanofluidic channel arrays, which have a width of about 40 nm, depth of 60 nm and length of 50 mum, were created using a focused-ion-beam milling instrument on a silicon nitride film swiftly and exactly, as is necessary. Stained -DNA molecules were put inside these sub-100 nm conduits by capillary force and they were stretched and transferred along these conduits, which were dealt with activating reagent Brij aqueous solution in advance. The movements of DNA molecules in these channels were discussed. These nano-structure channels may be useful in the study and analysis of the statics as well as the dynamics of single biomolecules.

DNA↗
PubMed2006

The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.

The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism.

Biocompatible Materials↗
PubMed2003

Frustrated nesting behaviour: relation to extra-cuticular shell calcium and bone strength in White Leghorn hens.

1. The inability of hens to express normal nesting behaviour in battery cages results in frustration, manifesting itself as stereotyped pacing. Frustration can cause hens to retain their eggs beyond the expected time of lay, resulting in an extra-cuticular layer of calcium on eggshells. 2. This study investigated whether frustrated nesting behaviour caused extra-cuticular calcification of eggshells and whether this loss of non-structural calcium to eggshells may have subsequently contributed to weak bones in spent hens. 3. One hundred and twenty hens were assigned to one of three treatments: NB (hens given nest boxes in their cages), NN (no nest box) and R (access to nest box periodically restricted). 4. NB hens spent the least amount of time pacing in the hour before oviposition. NN and R hens spent similar amounts of time pacing. 5. Contrary to expectation, eggshells from hens under different treatments yielded the same amount of extra-cuticular calcium. Similarly tibia strength did not significantly differ among treatments.

Animals↗
PubMed2001

[Protective effect of c-fos antisense oligonucleotides on brain damage induced by glutamate].

OBJECTIVE: To investigate the relation between glutamate neurotoxicity and c-fos gene expression. METHODS: c-fos antisense oligonucleotides (AS ODN) was injected into the right lateral ventricles of 9 SD rats to block the c-fos gene expression in brain tissue. c-fos sense oligonucleotides (S ODN) was used a control. The numbers and morphology of neurons in both cerebral cortex and hippocampal CA1 were detected by MIAS-300 image analysing instrument. c-fos gene expression in brain was observed by immunohistochemical method. The content of water and electrolytes in the brain tissue and Ca(2+) in the synapse were measured. RESULTS: The c-fos AS ODN blocked the c-fos gene expression and reduced the content of both water and sodium in brain tissue and Ca(2+) in symptosome, thus alleviating the morphological damage in neuron. S ODN did not have such effect. CONCLUSION: c-fos gene expression plays an important role in mediating the effect of glutamate neurotoxicity. Blocking the c-fos gene expression could antagonize glutamate neurotoxicity.

Animals↗
PubMed2001

The spinocerebellar ataxia type 1 protein, ataxin-1, has RNA-binding activity that is inversely affected by the length of its polyglutamine tract.

Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disease caused by the expansion of a polyglutamine tract within the SCA1 product, ataxin-1. Previously, using transgenic mice, it was demonstrated that in order for a mutant allele of ataxin-1 to cause disease it must be transported to the nucleus of the neuron. Using an in vitro RNA-binding assay, we demonstrate that ataxin-1 does bind RNA and that this binding diminishes as the length of its polyglutamine tract increases. These observations suggest that ataxin-1 plays a role in RNA metabolism and that the expansion of the polyglutamine tract may alter this function.

Ataxin-1↗
PubMed2000

Fluorescence detection of proteins in sodium dodecyl sulfate-polyacrylamide gels using environmentally benign, nonfixative, saline solution.

SYPRO Tangerine stain is an environmentally benign alternative to conventional protein stains that does not require solvents such as methanol or acetic acid for effective protein visualization. Instead, proteins can be stained in a wide range of buffers, including phosphate-buffered saline or simply 150 mM NaCl using an easy, one-step procedure that does not require destaining. Stained proteins can be excited by ultraviolet light of about 300 nm or with visible light of about 490 nm. The fluorescence emission maximum of the dye is approximately 640 nm. Noncovalent binding of SYPRO Tangerine dye is mediated by sodium dodecyl sulfate (SDS) and to a lesser extent by hydrophobic amino acid residues in proteins. This is in stark contrast to acidic silver nitrate staining, which interacts predominantly with lysine residues or Coomassie Blue R, which in turn interacts primarily with arginine and lysine residues. The sensitivity of SYPRO Tangerine stain is similar to that of the SYPRO Red and SYPRO Orange stains - about 4-10 ng per protein band. This detection sensitivity is comparable to colloidal Coomassie blue staining and rapid silver staining procedures. Since proteins stained with SYPRO Tangerine dye are not fixed, they can easily be eluted from gels or utilized in zymographic assays, provided that SDS does not inactivate the protein of interest. This is demonstrated with in-gel detection of rabbit liver esterase activity using alpha-naphthyl acetate and Fast Blue BB dye as well as Escherichia coli beta-glucuronidase activity using ELF-97 beta-D-glucuronide. The dye is also suitable for staining proteins in gels prior to their transfer to membranes by electroblotting. Gentle staining conditions are expected to improve protein recovery after electroelution and to reduce the potential for artifactual protein modifications such as the alkylation of lysine and esterification of glutamate residues, which complicate interpretation of peptide fragment profiles generated by mass spectrometry.

Amino Acid Sequence↗
PubMed2000

Identification and genetic mapping of four novel genes that regulate leaf development in Arabidopsis.

Molecular and genetic characterizations of mutants have led to a better understanding of many developmental processes in the model system Arabidopsis thaliana. However, the leaf development that is specific to plants has been little studied. With the aim of contributing to the genetic dissection of leaf development, we have performed a large-scare screening for mutants with abnormal leaves. Among a great number of leaf mutants we have generated by T-DNA and transposon tagging and ethyl-methae sulfonate (EMS) mutagenesis, four independent mutant lines have been identified and studied genetically. Phenotypes of these mutant lines represent the defects of four novel nuclear genes designated LL1 (LOTUS LEAF 1), LL2 (LOTUS LEAF 2), URO (UPRIGHT ROSETTE). and EIL (ENVIRONMENT CONDITION INDUCED LESION). The phenotypic analysis indicates that these genes play important roles during leaf development. For the further genetic analysis of these genes and the map-based cloning of LL1 and LL2, we have mapped these genes to chromosome regions with an efficient and rapid mapping method.

Arabidopsis↗
PubMed2000

[Experimental study of protective effect of qingkailing on glutamate induced neurotoxic damage of brain].

OBJECTIVE: To observe the effect of Qingkailing (QKL) on glutamate induced damage of brain, in order to seek for effective drugs for antagonizing neurotoxicity of glutamate. METHODS: Number and morphology metrology of neuron in cerebral cortex and hippocampus were detected by using MIAS-300 image analysing instrument, electron microscope and immunohistochemical methods. RESULTS: QKL could allevate the glutamate induced accumulation of water and sodium in the brain tissue, relief the damage of cerebral cells and reduce the percentage of c-fos positive cell in brain. CONCLUSION: QKL could protect brain damage induced by glutamate, which might be related to inhibition of QKL on glutamate caused enhancement of c-fos gene expression.

Animals↗
PubMed2000

[Determining the distribution of Mutans Streptococci in human dental plaque by monoclonal antibody against SA I/II and SPAa of Mutans Streptococci].

OBJECTIVE: To explore the possibility of detecting the distribution of Mutans Streptococci in human dental plaque by Monoclonal antibody (WC2E10c, WC3A6d) against SA I/II and SPAa of Mutans Streptococci, which was prepared in our lab. METHODS: 60 subjects were divided into the experimental group and the control group. The distributions of Mutans Streptococci (serotype c and d) in dental plaques were detected in 60 subjects by the clonal blot technique. Positive colonies were examined by bacterial morphology, serology, biochemistry and SDS-PAGE. RESULTS: Bacterial colony was significantly different between the experimental group and the control group with eye observation. Colonies of the experimental group were deep brown and easily differentiated, but colonies of control group were white. Brown colonies were proved to be Mutans Streptococci (serotype c and d) by using assay of bacterial morphology, serology, biochemistry and SDS-PAGE, but white colonies were not. CONCLUSION: McAbs (WC2E10c, WC3A6d) were shown high specificity in Mutans Streptococci (Serotype c and d) of human dental plaques.

Adolescent↗
PubMed1999

Constitutive activation of the delta opioid receptor by mutations in transmembrane domains III and VII.

We have investigated whether transmembrane amino acid residues Asp128 (domain III), Tyr129 (domain III) [corrected], and Tyr308 (domain VII) in the mouse delta opioid receptor play a role in receptor activation. To do so, we have used a [35S]GTPgammaS (where GTPgammaS is guanosine 5'-3-O-(thio)triphosphate) binding assay to quantify the activation of recombinant receptors transiently expressed in COS cells and compared functional responses of D128N, D128A, Y129F, Y129A, and Y308F point-mutated receptors to that of the wild-type receptor. In the absence of ligand, [35S]GTPgammaS binding was increased for every mutant receptor under study (1.6-2.6-fold), suggesting that all mutations are able to enhance constitutive activity at the receptor. In support of this finding, the inverse agonist N,N-diallyl-Tyr-Aib-Aib-Phe-Leu (where Aib represents alpha-aminobutyric acid) efficiently reduced basal [35S]GTPgammaS binding in the mutated receptor preparations. The potent agonist BW373U86 stimulated [35S]GTPgammaS binding above basal levels with similar (D128N, Y129F, and Y129A) or markedly increased (Y308F) efficacy compared with wild-type receptor. BW373U86 potency was maintained or increased. In conclusion, our results demonstrate that the mutations under study increase functional activity of the receptor. Three-dimensional modeling suggests that Asp128 (III) and Tyr308 (VII) interact with each other and that Tyr129 (III) undergoes H bonding with His278 (VI). Thus, Asp128, Tyr129, and Tyr308 may be involved in a network of interhelical bonds, which contributes to maintain the delta receptor under an inactive conformation. We suggest that the mutations weaken helix-helix interactions and generate a receptor state that favors the active conformation and/or interacts with heterotrimeric G proteins more effectively.

Amino Acid Substitution↗
PubMed1999

Characterization of SYBR Gold nucleic acid gel stain: a dye optimized for use with 300-nm ultraviolet transilluminators.

The highest sensitivity nucleic acid gel stains developed to date are optimally excited using short-wavelength ultraviolet or visible light. This is a disadvantage for laboratories equipped only with 306- or 312-nm UV transilluminators. We have developed a new unsymmetrical cyanine dye that overcomes this problem. This new dye, SYBR Gold nucleic acid gel stain, has two fluorescence excitation maxima when bound to DNA, one centered at approximately 300 nm and one at approximately 495 nm. We found that when used with 300-nm transillumination and Polaroid black-and-white photography, SYBR Gold stain is more sensitive than ethidium bromide, SYBR Green I stain, and SYBR Green II stain for detecting double-stranded DNA, single-stranded DNA, and RNA. SYBR Gold stain's superior sensitivity is due to the high fluorescence quantum yield of the dye-nucleic acid complexes ( approximately 0.7), the dye's large fluorescence enhancement upon binding to nucleic acids ( approximately 1000-fold), and its capacity to more fully penetrate gels than do the SYBR Green gel stains. We found that SYBR Gold stain is as sensitive as silver staining for detecting DNA-with a single-step staining procedure. Finally, we found that staining nucleic acids with SYBR Gold stain does not interfere with subsequent molecular biology protocols.

Animals↗
PubMed1999

Comparison of SYBR Green I nucleic acid gel stain mutagenicity and ethidium bromide mutagenicity in the Salmonella/mammalian microsome reverse mutation assay (Ames test).

SYBR Green I nucleic acid gel stain is an unsymmetrical cyanine dye developed for sensitive detection of nucleic acids in electrophoretic gels. Its mechanism of nucleic acid binding is not known, whereas the most commonly used nucleic acid gel stain, ethidium bromide, is a well-characterized intercalator. We compared the mutagenicity of SYBR Green I stain with that of ethidium bromide in Salmonella/mammalian microsome reverse mutation assays (Ames tests). As expected [J. McCann, E. Choi, E. Yamasaki, B.N. Ames, Proc. Natl. Acad. Sci. USA, 72 (1975) 5135-5139], ethidium bromide showed high revertant frequencies in several frameshift indicator strains (averaging 68-fold higher than vehicle controls in TA98, 80-fold higher in TA1538, 15-fold higher in TA1537, and 4.4-fold higher in TA97a), only in the presence of rat liver extracts (S9). Small increases in revertant frequencies were observed for ethidium bromide in the base-substitution indicator strain TA102 both in the presence and absence of S9 (averaging 2.0- and 1.8-fold higher than vehicle controls, respectively) and in base-substitution indicator strain TA100 in the presence of S9 (averaging 1.6-fold higher than vehicle controls). A small mutagenic effect was detected for SYBR Green I stain in frameshift indicator strain TA98 (averaging 2. 2-fold higher than vehicle controls) only in the absence of S9 and in base-substitution indicator strain TA102, both in the presence and absence of S9 (averaging 2.2- and 2.7-fold higher than vehicle controls, respectively). Thus, SYBR Green I stain is a weak mutagen and appears to be much less mutagenic than ethidium bromide. These results suggest that SYBR Green I stain may not intercalate, and if it does, that its presence does not give rise to point mutations at a high frequency.

Animals↗
PubMed1999

Understanding peptic ulcer disease pharmacotherapeutics.

The implication that Helicobacter pylori is responsible for peptic ulcer disease (PUD) has revolutionized the pharmacotherapeutic management of PUD. There has been a shift from long-term therapy with antacids and histamine2 (H2) antagonists to short-term therapy with triple antimicrobials with or without an antisecretory agent or a double antimicrobial therapy with an antisecretory agent. A case of PUD in a 53-year-old woman and its management with double antimicrobial agents and an antisecretory agent is discussed. Research evidence suggests that a treatment regimen aimed at eradicating H. pylori without diagnostic testing enhances the ability to effectively manage suspected cases of PUD before complications arise and referrals to specialists are necessary. Discouraging the use of over-the-counter H2 antagonists, ruling out long-term use of nonsteroidal anti-inflammatory drugs before selecting the treatment regimen, and considering expected treatment compliance are important aspects of PUD management that emerged from this case.

Anti-Bacterial Agents↗
PubMed1999

[Changes of glutamate and GABA in cerebrospinal fluid of patients with pneumonia complicated with central nervous system damage].

Glutamate(Glu), gamma-aminobutyric acid(GABA), and malondialdehyde(MDA) in cerebrospinal fluid (CSF) were measured in 18 children with pneumonia complicated with central nervous system(CNS) damage, 14 children with pneumonia without CNS damage, and 7 children with hypocalcemic tetany. The concentration of Glu and MDA and the ratio of Glu/GABA in CSF of pneumonia without CNS damage were significantly higher than the others. The ratio of Glu/GABA in CSF of the children with pneumonia with consciousness obstacle after convulsion was higher than that without consciousness obstacle after convulsion. These results suggest that Glu and free radicals may play a critical role in the CNS damage caused by pneumonia, however GABA may reduce the CNS damage caused by pneumonia.

Brain Diseases↗
PubMed1999

[A study on the biological properties of fimbriae of Actinomyces viscosus. I. The preparation and determination of fimbriae of A. viscosus].

OBJECTIVE: To build up the methods to prepare and determine the fimbriae of A. viscosus. METHODS: Type 1 and 2 fimbriae were prepared from A. viscosus 5519 and 5951 respectively. Fimbriae were isolated from bacteria cells by mechanical shaking, obtained by collecting the supernatant after centrifugation, and purified by ammonium sulfate precipitations and gel filtration. RESULTS: Electron microscope showed that fimbriae existed in the preparations. The immunological reaction between the fimbriae preparations and specific antibodies against fimbriae attested that they were type 1 or type 2 fimbriae. CONCLUSION: The present study become a foundation for further study on the biological properties of fimbriae of A. viscosus.

Actinomyces viscosus↗