Biomedical subjects

Xiaoyan Zhao

Publications and source records attributed to Xiaoyan Zhao.

9 recordsLinked to original sources

PubMed2006

Proteomic analysis of secreted proteins in early rheumatoid arthritis: anti-citrulline autoreactivity is associated with up regulation of proinflammatory cytokines.

OBJECTIVES: To identify peripheral blood autoantibody and cytokine profiles that characterise clinically relevant subgroups of patients with early rheumatoid arthritis using arthritis antigen microarrays and a multiplex cytokine assay. METHODS: Serum samples from 56 patients with a diagnosis of rheumatoid arthritis of <6 months' duration were tested. Cytokine profiles were also determined in samples from patients with psoriatic arthritis (PsA) and ankylosing spondylitis (n = 21), and from healthy individuals (n = 19). Data were analysed using Kruskal-Wallis test with Dunn's adjustment for multiple comparisons, linear correlation tests, significance analysis of microarrays (SAM) and hierarchical clustering software. RESULTS: Distinct antibody profiles were associated with subgroups of patients who exhibited high serum levels of tumour necrosis factor (TNF)alpha, interleukin (IL)1beta, IL6, IL13, IL15 and granulocyte macrophage colony-stimulating factor. Significantly increased autoantibody reactivity against citrullinated epitopes was observed in patients within the cytokine "high" subgroup. Increased levels of TNFalpha, IL1alpha, IL12p40 and IL13, and the chemokines eotaxin/CCL11, monocyte chemoattractant protein-1 and interferon-inducible protein 10, were present in early rheumatoid arthritis as compared with controls (p<0.001). Chemokines showed some of the most impressive differences. Only IL8/CXCL8 concentrations were higher in patients with PsA/ankylosing spondylitis (p = 0.02). CONCLUSIONS: Increased blood levels of proinflammatory cytokines are associated with autoantibody targeting of citrullinated antigens and surrogate markers of disease activity in patients with early rheumatoid arthritis. Proteomic analysis of serum autoantibodies, cytokines and chemokines enables stratification of patients with early rheumatoid arthritis into molecular subgroups.

Adult↗

PubMed2006

[Equivalence analysis of disyllabic Mandarin speech test materials].

OBJECTIVE: To evaluate the equivalence of difficulty of disyllabic Mandarin Speech Test Materials (MSTM) in order to facilitate wider use of speech audiometry in Chinese audiology clinics. METHOD: The Mandarin disyllabic materials, including 10 lists with 50 words in each, have been recorded and converted digitally into CD format. Sixty-five subjects (the age-range 18-25 years) with normal hearing who speak Mandarin well in their daily lives participated in this study. Five of them joined the pilot study, which aimed to identify a presentation level which would be used into the formal test. The other sixty subjects participated in the formal speech perception test. The results were analyzed statistically with Statistical Package for the Social Sciences Software Version 11.0 (SPSS 11.0). RESULT: Nine of the 10 lists were found to have equal difficulty with application of the ANOVA and SNK-Q statistical methods. CONCLUSION: Nine lists of 50 words of these Mandarin disyllabic materials can be considered to have equal difficulty and could be used in a clinical setting.

Adolescent↗

PubMed2004

MALDI-TOF MS detection of dilute, volume-limited peptide samples with physiological salt levels.

This paper presents a highly efficient sample preparation technique for matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The purpose of the research is to use a conventional MALDI support to directly and conveniently detect sub-nM levels of peptides from volume-limited samples with physiological salt levels. In this new method, highly uniform matrix-nitrocellulose spots with a 500 microm diameter were conveniently generated by direct contact of a capillary tip to a stainless steel MALDI plate. An array of 50 microspots can be blotted from 1 microL matrix-nitrocellulose solution within 1 min. It was found that the addition of high concentration nitrocellulose to the alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix solution is critical for the formation of microspots. Samples are deposited on top of those microspots and incubated for 3 min. The CHCA-nitrocellulose surface shows a significant peptide binding capability for sub-nM levels of peptide. Restricting the matrix spot diameter to 500 microm gives an analyte enrichment effect because the peptides are confined to a small solid-phase surface area. Selective peptide binding is seen even with >0.15 M salt levels. Loading small aliquots of samples with multiple applications allows low level peptide detection down to 100 pM. Push-pull perfusates collected from the rat striatum were successfully analyzed with the microspot method.

Animals↗

PubMed2004

Competitive immunoassay for microliter protein samples with magnetic beads and near-infrared fluorescence detection.

A competitive immunoassay with near-infrared (NIR) fluorescence detection to analyze microliter biological samples with an amol limit of detection (LOD) is described. An important feature about this technique is that the immunoreaction and fluorescence detection are separated into two distinct steps, allowing for independent optimization. In the immunoreaction step, NIR fluorescence-labeled antigen (Ag) competes with the unlabeled analyte (Ag) for antibodies (Ab) immobilized on the surface of paramagnetic beads. A magnet is then used to separate the bound antigen from the free in the supernatant. As the amount of Ag in the sample increases, there is less binding between Ag and immobilized Ab; therefore, the amount of Ag in the supernatant is proportionally related to the amount of Ag in the sample. In the fluorescence detection step, aliquots of the supernatant are concentrated onto a protein binding membrane by a capillary blotting technique with an optimized 33 nL/min flow rate. The fluorescence of the blotted spots is detected with a NIR sensitive photon counting system that is optimized to an instrumental LOD of 30 000 fluorophore molecules. This competitive assay demonstrates a sample LOD of 400 pg/mL of unlabeled rabbit immunoglobulin G spiked into bovine serum. This design features low sample volumes and reagent consumption.

Animals↗

PubMed2004

[Research on the basic properties of spontaneous otoacoustic emissions].

OBJECTIVE: To record and analyze the basic properties of spontaneous otoacoustic emission (SOAE) and to study the application of SOAE. METHOD: Forty cases (80 ears) with normally hearing subjects and 96 cases with abnormal hearing subjects were tested by ILO92 Otodynamics Analyzer. RESULT: (1) SOAE frequencies ranged from about 0.5 kHz to 6 kHz, it's amplitudes distributed between -28 and 6 dB SPL; (2) 49% had SOAE and there were no significant difference in sexuality in normal hearing subjects. During long duration observation, frequency of SOAE was no change; (3) Amplitude of SOAE could be suppressed by contralateral white noise; (4) There were some difference in different hearing loss group for SOAE. CONCLUSION: The presence of SOAE indicated that there is a better function for out hair cells of cochlear.

Adolescent↗

PubMed2003

Solid-phase immunoassay detection of peptides from complex matrices without a separation.

A simple and sensitive solid-phase fluorescence immunoassay method was developed to detect peptides without separating them from a biological matrix. A near infrared fluorescence detection system was constructed for scanning analyte spots blotted onto protein binding membranes. Hydrophobic membranes were used with a modified vacuum spot blotting system to concentrate the peptide solution into a small area and the overall assay time was thus reduced by eliminating blocking steps. Both direct and indirect immunoassay methods are demonstrated; the indirect is more sensitive and features a 1 pmol detection limit of neat dynorphin A solutions. To further increase the immunoassay sensitivity, a novel capillary blotting system with hydrophilic membranes was designed where optimized sample volumes of 167 nL were deposited for each spot. The area-reduced blotting method shows a 1000-fold improved, 1.3 fmol spot(-1) detection limit of a dynorphin A diluted in a buffered solution of 150 mg L(-1) of casein. Low-flow push-pull perfusates with volumes of 1 microL sampled from the striatum of the rat were assayed for dynorphin A by the method of standard addition. The detection limit was estimated to be 1.9 fmol in the low-flow push-pull perfusates. These data demonstrate a solid-phase near infrared immunofluorescence strategy for the study of peptides directly blotted from chemically complex biological fluid matrices.

Dynorphins↗

PubMed2003

[The inhibitory effect of extracts from Galla chinensis on marine fouling bacteria].

OBJECTIVE: To observe the activity of extracts from Galla Chinensis with different solvents against marine fouling bacteria in vitro. METHOD: Incubating plate with foveolae was used. RESULTS: The ethyl acetate, ethanol and water extracts showed strong inhibitory activity against marine fouling bacteria belonging to nine genera including Pseudomonas, Aeromonas, Alealigenes, Flavobacterium, Vibrio, Photobacterium, Moraxella, Chromobacterium, Enterobacter. While, the petroleum ether and chloroform extracts showed no inhibitory activity. CONCLUSION: The study provided theory basis for new biologic protective dope on environment.

Aeromonas↗

PubMed2003

Genotypes of CCR2 and CCR5 chemokine receptors in human myasthenia gravis.

The aim of this study was to examine the association of human autoimmune myasthenia gravis (MG) with two DNA polymorphisms of the chemokine receptors CCR5-Delta 32 and CCR2-64I. CCR2 and CCR5 interact primarily with the human CC family ligands CCL2 (formerly called monocyte chemoattractant protein; MCP-1), CCL3 and CCL4 (macrophage inflammatory protein-1 alpha and -1 beta; MIP-1 alpha/beta), and their main function is to recruit leukocytes from circulation into the tissues, thus playing an important role in human inflammatory disorders. A PCR-based genotyping method was used to determine the genetic variation at the CCR5 gene and an automated real-time Pyrosequencing technology was employed for the analysis of G right curved arrow A point mutation at the CCR2 gene. Results obtained from 158 patients and 272 healthy controls demonstrate no evidence of association between genetic variants of CCR2 and CCR5 with MG and its clinical manifestations. CCR2-64I and CCR5-Delta 32 genotypes are thus unlikely to be involved in protection or predisposition to MG.

Female↗

PubMed2002

The histone deacetylase inhibitor trichostatin A derepresses the telomerase reverse transcriptase (hTERT) gene in human cells.

Activation of telomerase, essential for cellular immortalization and transformation, requires the induction of its catalytic component, telomerase reverse transcriptase (hTERT). However, biochemical and genetic mechanisms for the control of hTERT expression remain undefined. In the present study, we demonstrate that the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) induces hyperacetylation of histones at the hTERT proximal promoter, directly transactivates the hTERT gene in normal human telomerase-negative cells, and upregulates hTERT expression in telomerase-positive tumor cells. Overexpression of HDAC1 leads to repression of the hTERT promoter activity. TSA-mediated activation of the hTERT promoter is abolished by the mutation of Sp1 sites at the proximal promoter, suggesting that the effect of TSA is regulated through Sp1 motifs. We also show a physical interaction of Sp1 with HDAC1 and the presence of HDAC1 at the hTERT promoter region. Moreover, hyperacetylation of histones at the hTERT promoter is associated with the natural up-regulation of hTERT expression that occurs in activated T lymphocytes. Taken together, histone acetylation/deacetylation may be a common underlying feature to hTERT transactivation/repression in human normal and malignant cells.

Acetylation↗