Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and trace metals in the blood of nonoccupationally exposed residents living in the vicinity of a municipal solid waste incinerator and electric arc furnace.

This study examines levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and trace metals in the blood of the nonoccupationally exposed residents living in the vicinity of municipal solid waste incinerators (MSWIs) and electric arc furnaces (EAFs). The analysis found that older females had higher concentrations of PCDD/Fs and older males had higher body mass index (BMI) values and higher concentrations of PCDD/Fs. Moreover, sex appeared to affect the levels of PCDD/Fs because, overall, females showed higher levels of PCDD/Fs. The results of a principal component analysis indicated that the characteristics of the blood were more similar to the characteristics of the stack flux gas in MSWIs than those in EAFs. When sex, age, and BMI values were taken into consideration, none of the factors appeared to significantly affect PCDD/F and trace metal blood levels. However, when participants were divided into eight categories and analyzed, it was found that sex was the most important factor affecting levels of trace metals in blood and that males had higher concentrations of Pb, Al, Cd, and Cu.

[Expression of proto-oncogene Wip1 in breast cancer and its clinical significance].

OBJECTIVE: To investigate the expression of proto-oncogene Wip1 in breast cancer tissue and its clinical significance. METHODS: Through the uses of semi-RT-PCR, immunohistochemical technique and Western blot, the specimens from 70 patients of breast cancer and 20 normal controls were detected for Wip1 mRNA and protein expression. At the same time, the authors analyzed the relations between the expression of Wip1 in human breast cancer and different clinical pathologic parameters. RESULTS: RT-PCR: The values of gene expression of Wip1 mRNA in breast cancer tissue, pericancerous tissue and normal breast tissue were 0.715 +/- 0.087, 0.175 +/- 0.021 and 0.154 +/- 0.022 respectively. Thus the value of gene expression in breast cancer tissue was significantly higher than that in pericancerous tissue or normal breast tissue (P < 0.01). Immunohistochemistry: The high expression rates of Wip1 protein in breast cancer tissue, pericancerous tissue and normal breast tissue were 62.9% (44/70), 2.9% (2/70) and 0 (0/20) respectively and there was a significant difference among these three different tissues (P < 0.01). Western blot: The relative contents of Wip1 protein in breast cancer tissue, pericancerous tissue and normal breast tissue were 0.688 +/- 0.151, 0.251 +/- 0.043 and 0.234 +/- 0.044 respectively. The relative content of Wip1 protein in breast cancer tissue was significantly higher than that in pericancerous tissue or normal breast tissue (P < 0.01). The high expression of Wip1 protein was negatively correlated with the expression of p53, but it had nothing to do with tumor size, age, tumor staging, axillary lymph node metastasis and expressions of ER and PR. CONCLUSION: The high expression of Wip1 mRNA and its protein in breast cancer tissue may promote the growth of breast cancer. Wip1 may become a new target for therapy of breast cancer.

[Koumine-induced apoptosis of human colonic adenocarcinoma cells: the cell biological mechanism].

OBJECTIVE: To investigate the cell biological mechanism of koumine-induced apoptosis of human colonic adenocarcinoma cells. METHODS: The effects of LoVo cell koumine on the membrane potential, mitochondrial membrane potential, concentration of cytosolic free calcium, reactive oxygen species (ROS) and gap junctional intercellular communication was observed by laser scanning confocal microscopy. RESULTS AND CONCLUSION: Koumine lowered the membrane potential and mitochondrial membrane potential of LoVo cells and decreased the concentration of free cytosolic calcium, which was increased to a level higher than the basal one after addition of EDTA. Koumine also increased the reactive oxygen species and enhanced the gap junctional intercellular communication of LoVo cells. These findings may explain the possible mechanisms of koumine-induced LoVo cell apoptosis.

[Methylation status and protein expression of adenomatous polyposis coli (APC) gene in breast cancer].

BACKGROUND & OBJECTIVE: Protein expression product of adenomatous polyposis coli (APC) gene is an important component of Wnt signal transduction pathway. APC gene inactivation leads to dysfunction of beta-catenin protein degradation, and then activates Tcf/Lef and causes abnormal transcription of oncogenes, such as c-myc, c-jun and cyclin D1, finally leads to carcinogenesis. This study was to investigate the correlation of methylation status of APC gene promoter 1A to protein expression of APC gene in breast cancer, and analyze the correlation of aberrant methylation of APC gene to clinicopathologic features of breast cancer. METHODS: Methylation status of APC gene promoter 1A in 76 specimens of breast cancer and corresponding adjacent tissues was detected by methylation-specific polymerase chain reaction; the expression of APC protein was detected by immunohistochemistry. RESULTS: The methylation rate of APC gene promoter 1A was significantly higher in breast cancer than in pericancerous normal breast tissue (36.8% vs. 0, P < 0.05). The positive rate of APC protein was significantly lower in breast cancer than in normal breast tissue (52.4% vs. 100%, P < 0.05). The promoter methylation of APC gene was positively correlated to TNM stage (r=0.296, P < 0.05), but negatively correlated to the expression of APC protein (r=-0.368, P < 0.05). CONCLUSION: Abnormal methylation of APC gene occurs in the progression of breast cancer, which is the main cause for the absence of APC protein expression, and the major mechanism of inactivation of APC gene.

[Over-expression in Escherichia coli and characterization of apolipoprotein AI].

Apolipoprotein AI (apo AI), the major protein component of human high-density lipoprotein (HDL), is a single-chain polypeptide of 243 amino acids. Several epidemiological studies have shown that the plasma concentrations of HDL has the role of reverse cholesterol transport (RCT) and inversely correlated with the incidence of coronary artery disease. Because apo AI lacks post-translational modifications, it is convenient to express human apo AI in Escherichia coli expression system. However, there is a poor stability of the mRNA and the apo AI protein in E. coli, it is difficult to express mature apo AI in recombinant bacteria, moreover, even as a fusion protein, apo AI is still sensitive to degradation and can not be cleaved efficiently from the fusion tags. In contrast, proapolipoprotein AI (proapo AI, having an additional polypeptide containing the amino acids Arg-His-Phe-Trp-Gln-Gln at the amino-teminal of the mature protein) proved stable and undegraded in Escherichia coli, and therefore, in this research, an expression system of E. coli including a plasmid of P(R)P(L) tandem promoter was adapted to produce proapo AI. Furthermore, site-directed mutagenesis of the proapo AI cDNA was performed to generate a Clu8Asp mutation in the amino-terminal sequence of proapo AI which created an acid labile Asp-Pro peptide bond between amino acid 8 and 9, and permitted specific chemical cleavage to remove pro-peptide. After inducing with a shift of temperature, yields of recombinant proapo AI achieved about 40% of total cell protein and the recombinant proapo AI expressed proved as a form of inclusion body in cells, so protein need to renature. First of all, the protein was dissolved in buffer with denaturant, and renaturation was carried out on a hydrophobic interaction column (Phenyl Sepharose), ion-exchange chromatography and gel-filtration chromatography were then used to further purify the protein. The purified recombinant apo AI was detected by a set of tests including Western-blotting, Circular dichroism spectra and lipid-binding test, the results shown that recombinant apo AI has similar structural and lipid-binding properties identical to those of native plasma apo AI, which facilitates further research and application.