Occupational noise exposure and incident hypertension in men: a prospective cohort study.

The associations between occupational noise exposure and hypertension remain controversial because of the differences in study designs, exposure assessments, and confounding controls. This prospective study investigated the relationship between noise exposure and the 10-year risk of hypertension. A cohort of 578 male workers in Taiwan was followed from 1998 to 2008. All subjects were divided into high-, intermediate-, and low-exposure groups on the basis of noise exposure assessment. Cox regression models were used to estimate the relative risks of hypertension after adjustment for potential confounders. During the 7,805 person-years of follow-up, 141 hypertension cases were identified. Significant increases of 3.2 (95% confidence interval (CI): 0.2, 6.2) mm Hg in systolic blood pressure and 2.5 (95% CI: 0.1, 4.8) mm Hg in diastolic blood pressure between the baseline and follow-up measurements were observed in the high-exposure group. Participants exposed to ≥85 A-weighted decibels (dBA) had a 1.93-fold (95% CI: 1.15, 3.22) risk of hypertension compared with those exposed to <80 dBA. There was a significant exposure-response pattern (P = 0.016) between the risk of hypertension and the stratum of noise exposure. Prolonged exposure to noise levels ≥85 dBA may increase males' systolic and diastolic blood pressure levels. This association may translate into a higher incidence of hypertension.

Single nucleotide polymorphisms in the CDH17 gene of colorectal carcinoma.

AIM: To investigate the relationship between c.343A>G and c.2216A>C polymorphism sites in the CDH17 gene and colorectal carcinoma. METHODS: Ninety-three non-consanguineous colorectal carcinoma patients admitted to the Department of Oncology at the First Affiliated Hospital of Zhengzhou University were included in this study. Ninety-three peripheral venous blood samples, of approximately one milliliter from each patient, were collected between December 2009 and August 2010. The genomic DNA of these peripheral venous blood samples were extracted and purified using a Fermentas Genomic DNA Purification Kit (Fermentas, CA) according to the manufacturer's protocol. The single nucleotide polymorphisms (SNPs) of the liver-intestine cadherin (CDH17) gene c.343A>G and c.2216A>C were determined by the polymerase chain reaction-single strand conformation polymorphism method (PCR-SSCP) in 93 peripheral venous blood samples from patients suffering with colorectal carcinoma. Typical samples that showed different migration bands in SSCP were confirmed by sequencing. Directed DNA sequencing was used to check the correctness of the genotype results from the PCR-SSCP method. RESULTS: There was a significant association between the c.2216 A>C SNPs of the CDH17 gene and the tumor-node-metastasis (TNM) grade, as well as with lymph node status, in 93 peripheral venous blood samples from colorectal carcinoma patients. The genotype frequencies of A/C, A/A, and C/C were 12.90%, 33.33% and 53.76%, respectively. There was a significant correlation between lymph node metastasis, TNM grade, and the genotype distribution (P < 0.05). The C/C genotype raised the risk of lymph node metastasis and the TNM grade. There was a significant difference in the TNM grade and lymph node metastasis between the A/A and C/C genotypes (P = 0.003 and P = 0.013, respectively). Patients with colorectal carcinoma carrying the C allele tended to have a higher risk of lymph node metastasis and have a higher TNM grade. The difference between the TNM grades, as well as the lymph node metastasis of the two alleles, was statistically significant (P < 0.01). CONCLUSION: The SNPs of the CDH17 gene c.2216 A>C might be clinically important in the prognosis of colorectal carcinoma.

Inhibition effects of all trans-retinoic acid on the growth and angiogenesis of esophageal squamous cell carcinoma in nude mice.

BACKGROUND: The potential application of retinoic acid receptor activators, such as all trans-retinoic acid (ATRA), for treating various cancers have been studied both pre-clinically and clinically. Whether ATRA has an anticancer effect on human esophageal squamous cancer cell (ESCC) is still unknown. We have explored the anticancer effect of ATRA in ESCC, and in this study, the effects of ATRA on levels and patterns of expression of the vascular endothelial growth factor (VEGF) signal transduction pathway in transplantable tumor growth of the human ESCC cell line, EC9706, in nude mice. METHODS: The animal model of the ESCC xenograft was made by subcutaneous implantation of tumor cells into nude mice. Reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemical assays were used to detect the expression of the VEGF signal transduction pathway in ESCC xenograft tissues. RESULTS: Compared to the control group, the tumor inhibition rates in the low dose ATRA, high dose ATRA, and 5-FU groups were 83.21%, 88.32%, 91.02%, respectively. The protein and mRNA levels of VEGF were down-regulated after being treated with ATRA and 5-FU compared to the control group (P < 0.05). The study also revealed that ATRA specifically down-regulated VEGF and the component of the VEGF signal transduction pathway of CD31, CD34, and CD105 (component of the TGF-ß receptor) in ESCC xenograft tissues (P < 0.05). CONCLUSIONS: ATRA can significantly inhibit tumor growth and has anticancer effects on transplantable tumor growth of human ESCC cell line EC9706 in nude mice. These findings indicate that ATRA specifically down regulated VEGF and the components of VEGF signal transduction, which may be an important mechanism responsible for the neoangiogenesis inhibition of ESCC cells.

High-frequency hearing loss, occupational noise exposure and hypertension: a cross-sectional study in male workers.

BACKGROUND: The association between occupational noise exposure and hypertension is inconsistent because of an exposure bias caused by outer-ear measurements of noise levels among workers. This study used hearing loss values (HLVs) measured at 4 kHz and 6 kHz in both ears as a biomarker to investigate the chronic effects of noise exposure on hypertension in 790 aircraft-manufacturing workers. METHODS: Participants were divided into a high hearing loss (HL) group (n = 214; average HLVs ≥ 30 decibel [dB] at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.9 A-weighted decibel [dBA]), a median HL group (n = 302; 15 ≤ average HLVs < 30 dB at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.4 dBA) and a low HL group (n = 274; average HLVs < 15 dB at 4 kHz or 6 kHz bilaterally; 82.2 ± 5.1 dBA) based on the results of pure tone audiometry. Multivariate logistic regressions were used to estimate the risk of hypertension between groups. RESULTS: The prevalence rates of hypertension were significantly higher in the high HL (43.5%; p = 0.021) and median HL (42.1%; p = 0.029) groups than in the low HL group (33.2%). The high HL and median HL workers had 1.48-fold (95% confidence interval [95%CI] = 1.02-2.15; p = 0.040) and 1.46-fold (95%CI = 1.03-2.05; p = 0.031) higher risks of hypertension relative to the low HL workers. Employment duration was significantly and positively correlated with the risk of hypertension among workers with average HLVs ≥ 15 dB at 4 kHz (p < 0.001) and 6 kHz (p < 0.001) bilaterally. CONCLUSIONS: Our findings suggest that high-frequency hearing loss is a good biomarker of occupational noise exposure and that noise-induced hearing loss may be associated with the risk of hypertension.

[Retrovirus-mediated RNA inhibition of EphA2 gene expression in colon adenocarcinoma HCT-8 cells].

OBJECTIVE: To explore novel cancer gene therapy by retrovirus-mediated RNAi technique to suppress the endogenous EphA2 oncogene expression in colon adenocarcinoma HCT-8 cells. METHODS: Sequence information of EphA2 mRNA was selected and two complementary oligonucleotides with hairpin loop were designed. Retrovirus-mediated RNAi expression vector (pSIREN-EphA2) was then constructed and transfected into the HCT-8 cells. Inhibition of EphA2 protein expression was quantitatively determined by Western blot and immunohistochemistry assay (SP method). RESULTS: The construction of pSIREN-EphA2 vector was successful and confirmed by restriction enzyme analysis and DNA sequencing. The post-transfection level of EphA2 protein expressions was greatly reduced in HCT-8 cells transfected with pSIREN-EphA2, as compared with those of untransfected cells and the vector control (P < 0.001). CONCLUSIONS: EphA2 protein expression in HCT-8 cell line can be suppressed using recombinant retrovirus-mediated RNAi technique. This approach may provide a novel gene therapy against colonic adenocarcinoma.