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Biomedical subjects

X Bing

Publications and source records attributed to X Bing.

5 recordsLinked to original sources
PubMed2004

Clinical implication of expression of cyclooxygenase-2 and peroxisome proliferator activated-receptor gamma in epithelial ovarian tumours.

Expression of cyclooxygenase (COX)-2 plays a key role in tumorigenesis and development and peroxisome proliferator-activated receptor gamma (PPARgamma) has been implicated in the control of COX-2 expression in some tissues. The aim of this study is to investigate (1) whether expression of COX-2 and PPARgamma is associated with ovarian carcinogenesis and progression of ovarian tumours and (2) whether COX-2 expression is controlled through ligand-mediated activation of PPARgamma in ovarian carcinoma cells. For this purpose, the presence of COX-2 and PPARgamma was immunohistochemically examined in 71 epithelial ovarian carcinomas, 18 borderline tumours and 23 benign tumours and the levels of COX-2 and PPARgamma proteins were determined by enzyme immunoassay in four benign tumours, three borderline tumours and 12 carcinomas. The frequency of COX-2 and PPARgamma detection was significantly increased and decreased as lesions progressed to carcinoma, respectively. The COX-2 protein was not detected in the three borderline tumours, whereas PPARgamma protein was detected in all of them. COX-2 protein was detected in eight of the 12 carcinomas, whereas PPARgamma protein was detected in only two cases. In addition, PPARgamma protein was not detected in all of the eight carcinomas in which COX-2 protein was detected, suggesting that expression of PPARgamma and COX-2 was in a reciprocal relationship. Furthermore, in cultured ovarian carcinoma cells, Western blot revealed that PPARgamma and COX-2 expression was regulated conversely as a result of stimulation by 15-deoxy-Delta(12, 14) PGJ(2) (15-PGJ(2)), a PPARgamma activator. In addition, 15d-PGJ(2) suppressed tumour necrosis factor-alpha-induced-COX-2 expression, confirming the reciprocal correlation between COX-2 and PPARgamma. From these results, it was suggested that PPARgamma activation might suppress COX-2 expression via the nuclear factor-kappaB pathway in the ovarian carcinoma cells and that low expression of PPARgamma and high expression of COX-2 might be involved in carcinogenesis and progression of ovarian tumours.

Adenocarcinoma↗
PubMed1999

Gene fusion and expression of heat-labile and heat-stable enterotoxins of enterotoxigenic Escherichia coli.

The vaccine candidate comprising the genes that code the B subunit of the heat-labile enterotoxin (LT-B) and the heat-stable enterotoxin (ST) of enterotoxigenic E. coli (ETEC) had been constructed by recombinant genetic techniques. The 5'terminus of the gene encoding pro-ST was genetically fused to the 3'terminus of the LT-B gene. The pro-ST gene containing mature ST sequence and pro sequence which codes for the pro region of ST precursors was amplified by PCR from pSLN004 plasmid. To reduce toxicity of the ST in vitro was substituted Leu for Ala residue at position 14 of ST by oligonucleotide-directed site mutagenesis. For this construction, the expression of ST antigenicity and LT antigenicity were obtained when a five amino-acid or a nine-amino-acid linker were included between the LT-B and pro-ST moieties. The LT-B/pro-ST fusion peptides possessed no enterotoxic activity of heat-stable and heat-labile enterotoxins, and retained the ability to bind GM1 ganglioside. More importantly, these LT-B/pro-ST fusion peptides were immunogenic. The preparations containing the hybrid molecule elicited special antibodies that were to recognize native toxin in vitro.

Animals↗
PubMed1998

Qualitative bedside assay of increased human serum myoglobin by sandwich dot-immunogold filtration for the diagnosis of acute myocardial infarction.

We isolated and purified myoglobin (MYO) from human fresh skeletal muscle and prepared monoclonal and polyclonal antibody from it. A sandwich dot-immunogold filtration assay (DIGFA) for the detection of MYO was developed by using affinity purified sheep anti-MYO antibody as the first antibody for coating nitrocellulose membranes (NCMs; the support) and colloidal gold labelled monoclonal antibody (H3) as the second antibody (an indicator). The test can be completed in 3 min without incubation or any equipment. A reddish dot, indicating positivity, is obvious to the naked eye. No interferences from bilirubin, hemoglobin, rheumatoid factors and lipid were found. In order to use undiluted serum, the detection limit was set at 100 microg of MYO/l. Concentrations up to 30,000 microg/l can be measured without getting a "hook" effect. Serum MYO levels in 53 patients with acute myocardial infarction (AMI), 100 healthy individuals, seven patients with chest pain but without myocardial ischemia and in 39 patients with renal insufficiency were measured simultaneously by DIGFA and enzyme-linked immunosorbent assay (ELISA). All serum samples from patients had MYO concentrations above 100 microg/l by ELISA and were positive by DIGFA. Serum creatinine values were related to MYO test results. Healthy individuals had MYO levels below 85 microg/l by ELISA and were negative by DIGFA.

Adult↗
PubMed1991

X-ray analysis of the single chain B29-A1 peptide-linked insulin molecule. A completely inactive analogue.

A crystal structure of a totally inactive insulin molecule has been determined. For this insulin molecule, the first without detectable activity to be characterized, the A and B-chains are linked by a peptide bond between A1 Gly and B29 Lys. The molecule has retained all its normal self-association properties and it can also accommodate the two different conformations designated T and R, as seen in 4Zn native pig insulin crystals. The hexamers of the crosslinked insulin molecule were crystallized using the 4Zn insulin recipe of Schlichtkrull. The structure has been crystallographically refined with data extending to 2 A using restrained least-square methods. Comparison of the B29-A1 peptide crosslink insulin and the 4Zn native insulin reveals close structural similarities with the native dimer. The analysis of the structure confirms the earlier hypothesis that insulin structures in crystals are not in an active conformation and that a separation of N-terminal A-chain and C-terminal B-chain is required for interaction with the insulin receptor.

Amino Acid Sequence↗