PubMed Health⌕ Search

Biomedical subjects

Yan Shi

Publications and source records attributed to Yan Shi.

At least 37 records · Page 2Linked to original sources
PubMed2006

MyD88-dependent IL-1 receptor signaling is essential for gouty inflammation stimulated by monosodium urate crystals.

While it is known that monosodium urate (MSU) crystals cause the disease gout, the mechanism by which these crystals stimulate this inflammatory condition has not been clear. Here we find that the Toll/IL-1R (TIR) signal transduction adaptor myeloid differentiation primary response protein 88 (MyD88) is required for acute gouty inflammation. In contrast, other TIR adaptor molecules, TIRAP/Mal, TRIF, and TRAM, are not required for this process. The MyD88-dependent TLR1, -2, -4, -6, -7, -9, and -11 and IL-18 receptor (IL-18R) are not essential for MSU-induced inflammation. Moreover, MSU does not stimulate HEK cells expressing TLR1-11 to activate NF-kappaB. In contrast, mice deficient in the MyD88-dependent IL-1R showed reduced inflammatory responses, similar to those observed in MyD88-deficient mice. Similarly, mice treated with IL-1 neutralizing antibodies also showed reduced MSU-induced inflammation, demonstrating that IL-1 production and IL-1R activation play essential roles in MSU-triggered inflammation. IL-1R deficiency in bone marrow-derived cells did not affect the inflammatory response; however, it was required in non-bone marrow-derived cells. These results indicate that IL-1 is essential for the MSU-induced inflammatory response and that the requirement of MyD88 in this process is primarily through its function as an adaptor molecule in the IL-1R signaling pathway.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Interaction of [HgX4]2- with berberine by absorption and resonance Rayleigh-scattering spectra and their analytical applications.

In a diluted H2SO4 solution, Hg(II) reacts with halide anions X- (including Cl-, Br- and I-) to form anionic complexes [HgX4]2- that can further react with berberine to form ion-association complexes of [Ber]2[HgX4]. As a result, the absorption spectra change, their maximum absorption wavelengths are at 230 nm for [Ber]2[HgCl4], 278 nm for [Ber]2[HgBr4] and 300 nm for [Ber]2[HgI4]. However, among the three complexes, only [Ber]2[HgI4] can lead to distinctly enhanced resonance Rayleigh scattering (RRS), and a new RRS spectrum appears. The maximum RRS wavelength is located at 397 nm, and the RRS intensity is proportional to the concentration of berberine in the range of 0-2.5 microg mL-1. The optimum conditions, the influence factors for the reaction and the effects of coexisting substances have been investigated. A new, simple and fast RRS method for the determination of berberine based on the ion-association reaction of [HgI4]2- with Ber+ was developed. The method has high sensitivity and good selectivity; the detection limit for berberine (3 sigma/K) is 7.22 ng mL-1. The method can be applied to the determination of berberine in some Chinese patent drug and the extracts of Coptis Chinensis. Furthermore, the mechanism of the reaction and the reasons for RRS enhancement have been discussed.

Absorption↗
PubMed2006

Resonance Rayleigh scattering method for the determination of cationic surfactants with chromium(VI)-iodide system.

A method for detecting and identifying cationic surfactant in some chemical samples for daily use that include Head & Shoulder Ampoule and Slek Shower Lotion has been developed. In an acid medium, chromium(VI) oxidizes I(-) to produce I(2), I(2) binds excess of I(-) to form I(3)(-), and I(3)(-) can further react with a cationic surfactant (CS) (such as cetyldimethyl benzylammonium chloride (CDBAC), Zephiramine (Zeph), cetylpyridinium bromide (CPB), tetradecyl pyridinium bromide (TPB) and cetyltrimethylammonium bromide (CTAB)) to form ion-association complexes [CS][I(3)]. This results in a significant enhancement of resonance Rayleigh scattering (RRS) and appearance of new RRS spectra. The RRS spectral characteristics of the ion-association complexes, the influencing factors and the optimum conditions of the reactions have been investigated. The intensities of RRS are directly proportional to the concentration of CS. CS in samples are collected using a treated anion exchange column and subsequently complexed by I(3)(-); then the RRS intensities of CS complex are determined at 495 nm. The reactions have high sensitivities, and their detection limits are 7.05 - 9.62 ng/mL for different CS. The effects of foreign substances are investigated and the results show that the method has good selectivity.

Cations↗
PubMed2006

96-well electroporation method for transfection of mammalian central neurons.

Manipulating gene expression in primary neurons has been a goal for many scientists for over 20 years. Vertebrate central nervous system neurons are classically difficult to transfect. Most lipid reagents are inefficient and toxic to the cells, and time-consuming methods such as viral infections are often required to obtain better efficiencies. We have developed an efficient method for the transfection of cerebellar granule neurons and hippocampal neurons with standard plasmid vectors. Using 96-well electroporation plates, square-wave pulses can introduce 96 different plasmids into neurons in a single step. The procedure results in greater than 20% transfection efficiencies and requires only simple solutions of nominal cost. In addition to enabling the rapid optimization of experimental protocols with multiple parameters, this procedure enables the use of high content screening methods to characterize neuronal phenotypes.

Animals↗
PubMed2006

[Spectrometry study on the interaction of Magdala red and bovine serum albumin].

In the present paper, the interaction of Magdala red and bovine serum albumin(BSA) was studied by UV-absorption and fluorescence spectrometry. The results of UV-absorption spectrometry show that the way of the interaction of Magdala red and BSA should obey the Scatchard Model. In other words, Magdala should be combined to some certain regions of BSA. Meanwhile, taking advantage of fluorescence quenching, the reaction mechanism of Magdala with BSA was explored. Protein molecule conformation change is discussed by synchronous fluorescence spectrometry.

Animals↗
PubMed2006

[The interaction of acridine orange with anionic surfactant and its application to the determination of protein].

The change in the UV-absorption spectrum and fluorescence spectrum of acridine orange(AO) due to the addition of surfactant dodecyi benzene sulfonic acid sodium sait (SDBS) and bovine serum albumin(BSA) was studied. Meanwhile, the effects of the in situ formed AOAO dimer in SDBS as a fluorescence probe and BSA were discussed. A new method for the determination of BSA using fluorescence is presented. The results indicate that the method is sensitive and rapid. The linear range of determination is 0-4. 17 x 10(-7) mol x L(-1). The relative standard deviation is 1.9%, and the detection limit is 8.73 x 10(-10) mol x L(-1).

Acridine Orange↗
PubMed2005

Intestinal ischemia-reperfusion injury made leptin decreased.

To explore the role and the rule of leptin levels in severe traumatism, an ischemia-reperfusion injury model was established to observe change of leptin levels, and platelet activating factor, noradrenaline, lipopolysaccharide, and endothelin-1 were utilized to induce vascular endothelial cells. Leptin concentrations in serum and supernatant were detected by murine and human leptin radioimmunoassay. The results showed that the first serum leptin level significantly decreased after an injury of 60 min ischemia and 30 min reperfusion versus pre-experimental serum values, and leptin level in serum showed a variational trend to increase as reperfusion time extended; the second, supernatant leptin level significantly decreased after PAF and ET-1 treatments of 6 and 24 h versus the control group. It can be concluded that leptin maybe an inflammatory cytokine to play a protection role in acute inflammation and traumatism.

Animals↗
PubMed2005

A defect in deletion of nucleosome-specific autoimmune T cells in lupus-prone thymus: role of thymic dendritic cells.

To study central tolerance to the major product of ongoing apoptosis in the thymus, we made new lines of transgenic (Tg) mice expressing TCR of a pathogenic autoantibody-inducing Th cell that was specific for nucleosomes and its histone peptide H4(71-94). In the lupus-prone (SWR x NZB)F1 (SNF1) thymus, introduction of the lupus TCR transgene caused no deletion, but marked down-regulation of the Tg TCR and up-regulation of endogenous TCRs. Paradoxically, autoimmune disease was suppressed in the alphabetaTCR Tg SNF1 mice with induction of highly potent regulatory T cells in the periphery. By contrast, in the MHC-matched, normal (SWR x B10. D2)F1 (SBF1), or in the normal SWR backgrounds, marked deletion of transgenic thymocytes occurred. Thymic lymphoid cells of the normal or lupus-prone mice were equally susceptible to deletion by anti-CD3 Ab or irradiation. However, in the steady state, spontaneous presentation of naturally processed peptides related to the nucleosomal autoepitope was markedly greater by thymic dendritic cells (DC) from normal mice than that from lupus mice. Unmanipulated thymic DC of SNF1 mice expressed lesser amounts of MHC class II and costimulatory molecules than their normal counterparts. These results indicate that apoptotic nucleosomal autoepitopes are naturally processed and presented to developing thymocytes, and a relative deficiency in the natural display of nucleosomal autoepitopes by thymic DC occurs in lupus-prone SNF1 mice.

Animals↗
PubMed2005

DGGE analysis of 16S rDNA of ammonia-oxidizing bacteria in chemical-biological flocculation and chemical coagulation systems.

Microbial community DNA was extracted from activated sludge samples taken from a chemical bioflocculation process and a chemical coagulation process in Shanghai, China. 16S rDNA of ammonia-oxidizing bacteria (AOB)was amplified by nested polymerase chain reaction and fingerprinted by denaturing gradient gel electrophoresis for microbial structure analysis. The Shannon diversity index of each sample was determined. The results indicated that the microbial structure of AOB in chemical bioflocculation process was comparable at two operational conditions. The ammonia-oxidizing bacterial communities were similar in three channels of the chemical bioflocculation process and in three serial tanks in the chemical coagulation process at the same condition. The diversity of microbial structures in the chemical bioflocculation process was higher than in the chemical coagulation process, in which the microbial structure was similar to that in the influent. Although the microbial study provides insights to the nitrification removal, higher microbial diversity of AOB does not necessarily mean higher ammonia oxidization. Molecular analysis should be combined with chemical assays to optimize operational conditions.

Ammonia↗
PubMed2005

Inductive expression and characterization analysis of Paralichthys olivaceus pigment epithelium-derived factor in a virally infected cell line.

Pigment epithelium-derived factor (PEDF) is acknowledged to be a non-inhibitory member of the serine protease inhibitor (serpin) superfamily, with antiangiogenesis, and neuroprotective and immunoregulatory function, mainly in the tissues of nervous system. Here, A PEDF gene homolog, Paralichthys olivaceus PEDF (PoPEDF), was isolated from flounder embryonic cells (FEC) treated with UV-inactivated Grass carp hemorrhage virus (GCHV) and subsequently identified as a differentially expressed gene. The full length of PoPEDF cDNA is 1803bp with an open reading frame of 1212bp encoding a 403-amino-acid protein. This deduced protein contains an N-terminal signal peptide, a glycosylation site, a consensus serpin motif, and a 34-mer and a 44-mer fragment, all of which are very conserved in the PEDF family. PoPEDF gene exhibits a conserved exon-intron arrangement with 8 exons and 7 introns. This conserved evolutionary relationship was further confirmed by a phylogenetic analysis, where fish PEDFs and mammalian members formed a well-supported clade. Constitutive expression of PoPEDF was widely detected in many tissues. In response to UV-inactivated GCHV or poly(I:C), PEDF mRNA was upregulated in FEC cells with time. This is the first report on the transcriptional induction of PEDF in virally infected cells.

Amino Acid Sequence↗
PubMed2005

Determination of promethazine hydrochloride and its preparations by highly accurate nephelometric titration.

A highly accurate nephelometric titration for the determination of promethazine hydrochloride and its preparations was presented. The titration operating conditions were studied and the solubility product constant of promethazine tetraphenylboron precipitation was determined. The result of the titration is comparable to those of control experiments. The proposed method has been found to be accurate, precise, specific and linear.

Nephelometry and Turbidimetry↗
PubMed2005

[Analysis of characteristics of 72 cases of t(8;21) acute myeloid leukemia].

OBJECTIVE: To investigate the laboratorial and clinical characteristics of t(8;21) AML, and to compare the differences between patients with additional chromosomal abnormalities and those without additional aberrations. METHODS: Seventy-two cases of t(8;21) AML were analyzed retrospectively, including features of morphology, initial blood cells, cytogenetic G-banding karyotype, immunophenotype, AML1/ETO fusion gene and clinical outcome. In order to compare the characteristics of patients with additional chromosomal abnormalities with those with t(8;21) alone, these patients were divided into two groups according to their karyotype as follows: Group A included patients with t(8;21) alone; Group B included patients with additional aberrations. RESULTS: According to FAB classification, there were 65 cases of M2, 5 cases of M4 and 2 of M5. Cytogenetically, 45 cases (62.5%) were accompanied by additional chromosomal abnormalities. The main additional aberrations included -Y, +4, del(9q). There were no obvious differences between these two groups in their features of age distribution, bone marrow blast cells, Auer rods, eosinophilia, immunophenotype, as well as central nervous system leukemia occurrence and complete remission rate of induction, but a male prevalence and a lower initial WBC were observed in Group B. With a follow up of 1-96 months, the median survival time was much longer in group A (65 months) compared with group B (12 months), but there was no difference between the four main subgroups of group B. The estimated 3-year survival was (63.9+/-11.2)% in group A compared with (20.9+/-9.2)% in group B. CONCLUSION: Additional chromosomal abnormality is an adverse factor for prognosis of t(8;21) AML. The median survival time of patients with additional aberrations was much shorter than that of those without.

Adolescent↗
PubMed2005

Standardizing global gene expression analysis between laboratories and across platforms.

To facilitate collaborative research efforts between multi-investigator teams using DNA microarrays, we identified sources of error and data variability between laboratories and across microarray platforms, and methods to accommodate this variability. RNA expression data were generated in seven laboratories, which compared two standard RNA samples using 12 microarray platforms. At least two standard microarray types (one spotted, one commercial) were used by all laboratories. Reproducibility for most platforms within any laboratory was typically good, but reproducibility between platforms and across laboratories was generally poor. Reproducibility between laboratories increased markedly when standardized protocols were implemented for RNA labeling, hybridization, microarray processing, data acquisition and data normalization. Reproducibility was highest when analysis was based on biological themes defined by enriched Gene Ontology (GO) categories. These findings indicate that microarray results can be comparable across multiple laboratories, especially when a common platform and set of procedures are used.

Gene Expression Profiling↗
PubMed2005

Inactivation kinetics of guanidinium chloride on Penaeus vannamei beta-N-acetyl-D-glucosaminidase and the relationship of enzyme activity and its conformation.

The effects of guanidinium chloride (GuHCl) on the activity of Penaeus vannamei beta-N-acetyl-D-glucosaminidase (NAGase) have been studied. The results show that GuHCl, at appropriate concentrations, can lead to reversible inactivation of the enzyme, and the IC50 is estimated to be 0.6 M. Changes of activity and conformation of the enzyme in different concentrations of GuHCl have been studied by measuring the fluorescence spectra and its relative activity after denaturation. The fluorescence intensity of the enzyme decreases distinctly with increasing GuHCl concentrations, and the emission peaks appear red-shifted (from 339.4 to 360 nm). Changes in the conformation and catalytic activity of the enzyme are compared. The extent of inactivation is greater than that of conformational changes, indicating that the active site of the enzyme is more flexible than the whole enzyme molecule. The kinetics of inactivation has been studied using the kinetic method of the substrate reaction. The rate constants of inactivation have been determined. The value of k(+0) is larger than that of k'(+0) which suggests that the enzyme is protected by substrate to a certain extent during guanidine denaturation.

Acetylglucosaminidase↗
PubMed2005

Identification of vulnerable atherosclerotic plaque using IVUS-based thermal strain imaging.

Pathology and autopsy studies have demonstrated that sudden disruption of vulnerable atherosclerotic plaque is responsible for most acute coronary syndromes. These plaques are characterized by a lipid-rich core with abundant inflammatory cells and a thin fibrous cap. Thermal strain imaging (TSI) using intravascular ultrasound (IVUS) has been proposed for high-risk arterial plaque detection, in which image contrast results from the temperature dependence of sound speed. It has the potential to distinguish a lipid-laden lesion from the arterial vascular wall due to its strong contrast between water-bearing and lipid-bearing tissue. Initial simulations indicate plaque identification is possible for a 1 degrees C temperature rise. A phantom experiment using an IVUS imaging array further supports the concept, and results agree reasonably well with prediction.

Animals↗
PubMed2005

Motion artifact reduction for IVUS-based thermal strain imaging.

Thermal strain imaging (TSI) using intravascular ultrasound (IVUS) has the potential to identify lipid pools within rupture-prone arterial plaques and serve as a valuable supplement to current IVUS systems in diagnosing acute coronary syndromes. The major challenge for in vivo application of TSI will be cardiac motion, including bulk motion and tissue deformation. Simulations based on an artery model, including a lipid-filled plaque, demonstrate that effective bulk motion compensation can be achieved within a certain motion range using spatial interpolation. We also propose a practical imaging scheme to minimize mechanical strains caused by tissue deformation based on a linear least squares fitting strategy. This scheme was tested on clinical data by artificially superimposing thermal displacements corresponding to different temperature rises. Results suggest a 1-2 degrees C temperature rise is required to detect lipids in an atherosclerotic plaque in vivo.

Arteries↗