RESUMO
A survey of 420 exposures of mammography was performed with the parameters recorded. Entrance skin air kerma (ESAK) was measured and the mean glandular dose (MGD) was calculated according to the Dance's formula. Correlation analysis showed that several factors could affect the MGD level. Mann-whitney test and Non-parametric ANOVA analyses were used to compare the MGD level grouped by view type and radiographic systems. No significant difference was found in MGD between the craniocaudal (CC) group and the mediolateral oblique (MLO) group. The MGD level was higher in the CR group than in the other two groups. MGD was positively correlated with the compressed breast thickness (CBT). MGD varied with the half value layer (HVL) and increased first then decreased. The mean MGD level in China is about 1.6 mGy and is lower than the guidance level in the International Basic Safety Standards (IBSS).
Assuntos
Mamografia/efeitos adversos , Doses de Radiação , China , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
Cadmium (Cd) is widely dispersed in the environment due to occupational and personal (cigarette) emissions. Exposure of human embryonic kidney 293T (HEK-293T) cells to CdCl2 resulted in growth inhibition and apoptosis. Our previous studies demonstrated that JWA, a novel retinoic acid-inducible and cytoskeleton-associated gene, is a potential environmental-responsive gene with increased expression attributed to oxidative and heat-shock stresses. In the present study, JWA was also found to be responsive to Cd exposure. After treatment with 20 microM CdCl2 for 12 h, the expression level of JWA was increased with accompanied growth inhibition and apoptosis. In addition, knock-down JWA protein expression by using transient transfecting of HEK-293T cells with antisense JWA express vector showed a protective effect against Cd-induced apoptosis. To determine whether the upregulation of JWA by Cd involved regulation by transcriptional mechanisms, further reporter gene assays were employed, which demonstrated a marked increase in JWA promoter activity. In addition, elevated intracellular levels of ROS components (O2-* and H2O2) and activation of JNK, ERK, and MAPK were found with corresponding upregulation of JWA protein expression. These results suggest that Cd-induced growth inhibition and apoptosis may involve ROS generation and subsequent affect on MAPK signal pathway. JWA responsiveness to CdCl2 might be through both transcriptional and posttranslational mechanisms.
Assuntos
Apoptose/efeitos dos fármacos , Cloreto de Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Rim/efeitos dos fármacos , Apoptose/genética , Western Blotting , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , DNA Antissenso/farmacologia , Relação Dose-Resposta a Droga , Formazans/metabolismo , Inativação Gênica , Proteínas de Choque Térmico/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Rim/patologia , Proteínas de Membrana Transportadoras , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sais de Tetrazólio/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
OBJECTIVE: This case-control study was aimed to detect the single nucleotide polymorphisms (SNPs) in JWA promoter region, to assess the effect of SNP on transcriptional activity, and to probe the relationship between SNP and the risk of bladder cancer. METHODS: The design of one control per case was adopted. The JWA gene promoter region in 155 patients with bladder cancer and in 155 cancer-free controls was amplified by PCR-SSCP technique, and the SNP were confirmed by direct DNA sequencing. The recombinant plasmids of JWA promoter fragment which contain the SNP were constructed as CAT reporter gene and were transfected transiently into NIH 3T3 cells for disclosing whether SNP changes the transcriptional activity of the promoter. RESULTS: A novel SNP -76 G-->C at promoter region of JWA gene was found. The frequencies of the C allele and GC genotype at JWA promoter -76G-->C in bladder cancer group (10.00% and 20.00% respectively) were significantly higher than those in control group (5.16% and 10.32% respectively) (P < 0.05). The transcriptional activity of -76GC allele genotype was significantly down-regulated as compared with that of -76GG allele genotype (P < 0.01). Multivariate logistic regression analysis revealed that JWA polymorphism at promoter -76G-->C is an independent novel risk factor for bladder cancer. CONCLUSION: The JWA -76G-->C variant genotype may play an important role in transcription regulation of JWA gene and in the susceptibility to bladder cancer.
