[Enrichment Factors, Health Risk, and Source Identification of Heavy Metals in Agricultural Soils in Semi-arid Region of Hainan Island].

To understand the enrichment factors and pollution levels of heavy metals in agricultural soils in the semi-arid region of Hainan island, 1818 surface soil samples were collected in Gancheng Town and analyzed for their heavy metal contents and physicochemical composition. Correlation analysis was used to determine the heavy metal enrichment factors. The geo-accumulation index (Igeo), comprehensive ecological risk index (RI), and hazard index (HI), as well as carcinogenic risk (CR), were used to assess the degree of pollution and health risk. Positive matrix factorization (PMF) was used to determine the primary sources of pollution and priority sources. The average values of heavy metal contents in the topsoil were 22.7, 0.128, 33.4, 14.5, 0.032, 9.32, 32.5, and 43.3 mg·kg-1 for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. With the exception of Zn, the concentrations of other heavy metals in the topsoil were higher than the soil background values of Hainan, showing different degrees of heavy metal accumulation effect. The Igeo revealed that the major pollutant element in soils was As, followed by Cd and Cu. The RI showed that the proportion of soil samples that were high-risk level or worse was 29.4% of the total number of samples, among which As was the major source of risk. The health risk assessment results indicated that As, Cr, and Ni exposure presented carcinogenic risk for children with high CR values. Based on PMF, four major sources of heavy metals were identified in the study area. Hg was derived mainly from industrial sources, and As was closely associated with agricultural activities. Ni, Cu, Cr, and Zn were related to soil parent materials. Pb and Cd were associated with agricultural activities and traffic emissions. The PMF models combined with correlation analysis were useful for estimating the source apportionment of heavy metals in soils.

[Accumulation and Health Risk of Heavy Metals in Cereals, Vegetables, and Fruits of Intensive Plantations in Hainan Province].

The accumulation of some harmful elements in plants from intensive production systems pose a serious threat to human health. In this study, seven heavy metals(Cu, Pb, Zn, Cr, Cd, As, and Hg) and their distribution characteristics in the crops, vegetables, and fruits were analyzed alongside single factor evaluation and Nemero index analysis. Combined with dietary recommended consumption data from the Chinese Nutrition Society, the dietary exposure of heavy metals were further analyzed, and a consequent safety risk assessment was conducted. A total of 673 crop, vegetable, and fruit samples were collected from typical intensive production systems in Hainan Province. The results showed that the content of Cu, As, and Hg in the 673 plant samples was below the value of the national food standard. The exceed rates of Pb, Zn, Cr, and Cd were 2.67%, 3.71%, 2.53%, and 3.71%, respectively. The heavy metal comprehensive pollution degree of six species of plants showed the trend of leafy vegetables > tuber crops > non-leafy vegetables > legume crops > fruits > cereals. In particular, Cr in leafy vegetables showed significantly higher hazard quotients(HQ) than that in other types, and exceeded 1, suggesting a high potential health risk via the ingestion of heavy metals through leafy vegetables. The relatively lower hazard index(HI) values of tuber crops, non-leafy vegetables, legume crops, fruits, and cereals suggest that these types of plants are more suitable for intensive production systems.

Association between Ras association domain family 1A promoter methylation and esophageal squamous cell carcinoma: a meta-analysis.

RASSF1A has been reported to be a candidate tumor suppressor in esophageal squamous cell carcinoma (ESCC). However, the association between RASSF1A promoter methylation and ESCC remains unclear. Eligible studies were identified through searching PubMed, Medline, Web of Science, and the China National Knowledge Infrastucture database. Studies were pooled and odds ratios (ORs) with corresponding confidence intervals (CIs) were calculated. Funnel plots were also performed to evaluate publication bias. Twelve studies involving 859 cases and 675 controls were included in this meta-analysis. A significant association was observed between RASSF1A methylation and ESCC overall (OR = 11.7, 95% CI: 6.59-20.9, z=8.36, P<0.00001). Subgroup analysis showed that the OR for heterogeneous tissues was 5.35 (95% CI = 2.95-9.71) while for autologous tissues it was 16.0 (8.31-30.96). For patient sample size, the OR for the <50 subgroup was 9.92 (95% CI = 2.88-34.2) and for the 50 case group was 13.1 (95% CI = 6.59-25.91). The OR for a relationship between RASSF1A methylation and TNM stages was 0.27 (95% CI=0.10-0.77), whereas there were no significant differences in RASSF1A methylation in relation to gender and differentiation among ESCC cases. This meta-analysis suggests a significant association between RASSF1A methylation and ESCC.

Gene silencing of ß-catenin by RNAi inhibits proliferation of human esophageal cancer cells by inducing G0/G1 cell cycle arrest.

OBJECTIVES: The aim of the present study was to explore mechanisms underlying the effects of down-regulating ß-catenin expression on esophageal carcinoma (EC) cells. METHODS: Cell cycle distribution and apoptosis were determined using flow cytometry and annexin V apoptosis assay, respectively. Transmission electron microscopy (TEM) was used to examine changes in ultrastructure, while expression of cyclin D1 protein and mRNA was detected by western blot and real-time PCR. Proliferating cell nuclear antigen (PCNA) and extracellular signal-regulated kinase (ERK) 1/2 were evaluated by Western blot analysis. PCNA labeling index (LI) was determined by immunocytochemistry. RESULTS: Compared with pGen-3-con transfected and Eca-109 cells, the percentage of G0/G1-phase pGen-3-CTNNB1 transfected cells was obviously increased (P<0.05), with no significant difference among the three groups with regard to apoptosis (P>0.05). pGen-3-CTNNB1 transfected cells exhibited obvious decrease in cyclin D1 mRNA and protein expression (P<0.05) and the ultrastructure of Eca-109 cells underwent a significant change after being transfected with pGen-3-CTNNB1, suggesting that down-regulating ß-catenin expression can promote the differentiation and maturation. The expression of PCNA and the ERKI/2 phosphorylation state were also down-regulated in pGen-3-CTNNB1 transfected cells (P<0.05). At the same time, the PCNA labeling index was decreased accordingly (P<0.05). CONCLUSION: Inhibition of EC Eca-109 cellproliferation by down-regulating ß-catenin expression could improve cell ultrastructure by mediating blockade in G0/G1 through inhibiting cyclin D1, PCNA and the MAPK pathway (p-ERK1/2).

[The relationship between C20orf54 gene rs3746804 position single nucleotide polymorphism and susceptibility to esophageal squamous cell carcinoma].

OBJECTIVE: To explore the association of C20orf54 gene rs3746804 position single nucleotide polymorphism and susceptibility to esophageal squamous cell carcinoma (ESCC). METHODS: Purification of genomic DNA from whole blood was used the Maxwell(16) System. rs3746804 in C20orf54 was detected by direct sequencing in 434 ESCC patients from Changzhi (Shanxi province) and Linzhou (Henan province) and 554 healthy controls from Changzhi, Linzhou and including immigrators from Linzhou to Changzhi. RESULTS: For rs3746804, the genotypic frequencies of CT (37.5% vs 51.0%, 37.5% vs 52.0%), CC (44.2% vs 34.8%, 44.2% vs 33.0%) in Changzhi ESCC patients showed significant differences with healthy Changzhi controls and the healthy immigrator controls (all P < 0.05), and the frequencies of TT (18.3% vs 4.1%) and CC (44.2% vs 54.6%) in Changzhi ESCC patients showed significant differences with Linzhou ESCC patients (all P < 0.05). The genotypic frequencies of TT (4.1% vs 15.0%), CT (41.2% vs 52.0%) and CC(54.6% vs 33.0%) showed significant differences between Linzhou ESCC patients and the healthy immigrator controls (all P < 0.05), and the frequencies of TT (4.1% vs 14.1%) and CC(54.6% vs 34.8%) showed significant differences between Linzhou ESCC patients and Changzhi healthy controls (all P < 0.01). Meanwhile, there were significant differences between ESCC patients (including Changzhi and Linzhou ESCC patients) and healthy controls (including the healthy Changzhi, Linzhou and immigrator controls) in genotypic frequencies of CT (39.2% vs 48.7%) and CC (48.8% vs 38.2%) (all P < 0.01). CT and CT + TT genotype could decrease the risk of ESCC compared with the CC genotype (OR = 0.630, 95%CI 0.481 - 0.826; OR = 0.654, 95%CI 0.507 - 0.844). CONCLUSION: There is a closed relationship between SNP rs3746804 in C20orf54 and susceptibility to ESCC.

[A comparison and significance of plasma riboflavin levels in patients with esophageal squamous cell carcinoma versus Linzhou healthy migrants in Changzhi of Shanxi].

OBJECTIVE: To study the relationship between plasma riboflavin levels and esophageal squamous cell carcinoma. METHODS: We detected and compared plasma concentrations of riboflavin in patients with esophageal squamous cell carcinoma (ESCC) and immigrants of Linzhou living in Changzhi. Plasma riboflavin levels were quantified in 445 ESCC patients, 689 healthy control subjects and 347 immigrants of Linzhou living in Changzhi by using enzyme-linked immunosorbent assay. RESULTS: The plasma riboflavin levels in patients with ESCC were significantly lower than those in the healthy controls and immigrants of Linzhou living in Changzhi [(731.69 ± 330.67) µg/L vs (1090.43 ± 445.08) µg/L, (731.69 ± 330.67) µg/L vs (897.58 ± 177.78) µg/L, respectively, all P < 0.05], and the plasma riboflavin levels of the healthy controls were higher than those in the immigrants of Linzhou living in Changzhi (P < 0.05). CONCLUSION: Patients with ESCC have decreased plasma riboflavin levels as compared with the healthy controls and immigrants of Linzhou living in Changzhi, there exists a lack of riboflavin in ESCC patients, but the specific mechanism needs further study.

[Biosorption of Ag+ by heavy metals hyperresistant Bacillus cereus strain HQ-1].

A newly isolated Bacillus cereus strain HQ-1 was found to possess high capability to absorb silver ions. The study showed that the biosorption process could be described well by pseudo-second-order kinetic model and Freundlich isotherm model. Higher cell concentration was favorable to the biosorption. Temperature's effect on the biosorption was not obvious. The oxygenous and nitrogenous functional groups on the cell wall played a very important role in the process of biosorption. Microdeposits were formed by interaction between silver ions and biopolymers from the cell wall (such as polysaccharides, proteins and some hydrolysis).