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Biomedical subjects

Xuanxian Peng

Publications and source records attributed to Xuanxian Peng.

7 recordsLinked to original sources
PubMed2003

C3/Ig and Ig/C3 two-component-determined circulating immune complexes (TCIC) in patients with HCV infection.

In the present study, we measured the levels of immunoglobulin (Ig)- and complement 3 (C3)-determined circulating immune complexes (two-component-determined CIC, or TCIC) in hepatitis C virus (HCV)-infected patients. TCIC was dissected into C3/Ig-TCIC and Ig/C3-TCIC by a reciprocal use of coating and detecting antibodies. The current study was carried out in 117 infected HCV patients and 252 healthy controls. We found that C3/Ig-TCIC elevation was a common feature in patients with HCV infection. Positive rates and levels of C3/IgG-TCIC and C3/IgM-TCIC were significantly higher in the patients with abnormal alanine aminotransferase (ALT) than patients with normal ALT (70.6% vs. 17.0%, 0.56 OD vs. 0.47 OD and 0.71 OD vs. 0.65 OD, respectively, P<0.001). However, the levels of IgM/C3-TCIC and IgA/C3-TCIC were significantly higher in individuals with HCV infection than in healthy controls, whereas the level of IgG/C3-TCIC was significantly lower in the former group than in the latter group. In summary, our results suggest that IgG and C3 TCIC may play an important role in liver cell injury during the course of HCV infection and may be a hallmark for hepatitis C pathogenesis. Elevated C3/Ig-TCIC, accompanied by decreased Ig/C3-TCIC, forms a peculiar trait in HCV infection. Our findings thus provide new insights into HCV pathogenesis.

Adult↗
PubMed2003

Analysis of Ig/Ig two-component-determined circulating immune complexes (TCIC) provide new insights into host immunity.

There have been many reports on circulating immune complexes (CIC), but information regarding Ig/Ig two-component-determined circulating immune complexes (TCIC) is not available. In the present study, we measured the levels of heterogeneous Ig/Ig two-component-determined circulating immune complexes (Ig/Ig-TCIC) in healthy individuals and patients with hepatitis A, Graves' disease and gastric cancer. The heterogeneous Ig/Ig-TCIC was dissected into IgM/IgG-TCIC, IgG/IgA-TCIC and IgA/IgM-TCIC by use of coating and detecting antibodies. The current study has been carried out in 383 cases of healthy individuals, 97 cases of hepatitis A, 108 cases of Graves' disease and 126 cases of gastric cancer. We found that changes on the levels of IgM/IgG-TCIC and IgG/IgA-TCIC is a common feature in patients studied in this study. A total of 71.4% and 80% of patients with gastric cancer had decreased IgM/IgG-TCIC and IgG/IgA-TCIC, respectively. In addition, elevated frequencies were found in patients with hepatitis A and Graves' diseases for IgM/IgG-TCIC (51.5% and 38.0%, respectively) and IgG/IgA-TCIC (29.9% and 19.4%, respectively). In summary, our results suggest that Ig/Ig-TCIC may be a hallmark for evaluation of host immunity. Decreased frequency in gastric cancer and increased frequencies in hepatitis A and Graves' disease forms a peculiar trait for detection of IgM/IgG-TCIC and IgG/IgA-TCIC. Our findings have, thus, provided new insights into circulating immune complexes.

Adolescent↗
PubMed2002

Identification of shiga toxin-producing bacteria by a new immuno-capture toxin gene PCR.

Infections with bacteria producing shiga toxin are responsible for widespread disease and for the death of a large number of people. In the present study, we have developed a rapid method of high specificity for the detection of Shigella dysenteriae by combining immuno-capture of the bacteria and polymerase chain reaction (PCR) amplification of their toxin gene. We compared the sensitivity of our new method, referred to as immuno-capture toxin gene PCR (iTGPCR), with a conventional TGPCR (cTGPCR) method in detecting S. dysenteriae. Approximately 100 colony forming units (CFU) of bacteria in a volume of 400 microl were divided into 20 tubes with 5 CFU (20 microl). One group of 10 tubes was analyzed by iTGPCR and the other by cTGPCR amplification. All were positive in the 10 tubes using iTGPCR but, in contrast, only half were positive in the 10 tubes with the cTGPCR method. This method was used to detect S. dysenteriae type I in sewage samples without the normal tedious preparation methods. These findings suggest that iTGPCR gives enhanced test sensitivity, and allows determination of pathogen serotype, and differentiation of toxin-producing strains from non toxin-producing strains.

Antibodies, Bacterial↗
PubMed2002

Immuno-capture PCR for detection of Aeromonas hydrophila.

In this report, we describe the use of universal primer PCR (UPPCR) for the detection of 16S ribosomal RNA (rRNA) genes from Aeromonas hydrophila captured by anti-A. hydrophila antibody coupled to a microplate. The approach combining immuno-capture with UPPCR provides a quick, sensitive, and reproducible way for the detection of bacterial cells.

Aeromonas hydrophila↗
PubMed2002

[Transcriptional activation function of hepatitis B virus Pre S1 protein in yeast].

BACKGROUND: To explore the feasibility of cloning of the hepatocyte receptor interacting with the Pre S1 protein of HBV by two hybrid system. METHODS: Yeast expression plasmids encoding fusion proteins of full length or portions of Pre S1 of HBV and DNA binding domain of yeast protein GAL4 were constructed and used to transform yeast reporter strain SFY526. Reporter gene product ?galactosidase activity was assayed as a measure of transcription activation in yeast. Mammalian expression plasmid encoding fusion proteins of full length Pre S1 and DNA binding domain of GAL4 was constructed and used to cotransfect hepatoma cell line Huh?7 together with CAT reporter plasmid. Cell extracts were assayed for CAT activity by thin?layer chromatography. RESULTS: The fusion proteins of full length Pre S1 protein and GAL4 DNA binding domain present transcriptional activation function in yeast. The transcription activating sequence is localized to the 21 to 47 amino acids of Pre S1 protein Fusion proteins of full length Pre S 1 and GAL 4 DNA binding domain do not show transcriptional activation function in mammalian cells. CONCLUSION: The transcriptional activating sequence of HBVPre S1 protein in yeast overlaps the hepatocyte receptor binding site. The transcriptional activation function of HBV Pre S1 protein in yeast may prevent researchers?from using yeast two hybrid system to clone HBV receptor interacting with Pre S1 protein. However, the Pre S1 protein does not show transcriptional activation function in mammalian cells. Mammalian two?hybrid system may be a practical method to clone the HBV hepatocyte receptor interacting with Pre S1 protein.

DNA-Binding Proteins↗