ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Both epidemiological and experimental studies have shown that physical exercise deserves particular attention in any consideration of approaches to the prevention of neoplasia, especially since it also exerts consistent beneficial effects on the other major chronic diseases prevalent in the Western world, atherosclerosis and non-insulin dependent diabetes mellitus (NIDDM). The organ sites for which strong evidence has been gained for a protective influence of exercise or an elevated risk with a sedentary existence include the colon, prostate, breast and endometrium. The underlying mechanisms appear to centre on the hormones insulin and oestrogen, serum elevation of both of these endocrine factors being associated with increased risk of neoplastic development. The immense potential benefit of an increased level of exercise in the general population suggests that commensurate measures should be taken in the field of cancer education

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Barrett's oesophagus is associated with an increased risk of oesophageal adenocarcinoma. In 1985, Sontag el al reported an association between Barrett's oesophagus and colorectal cancer. This association has become controversial owing to conflicting evidence. Two recent papers indicate that although the prevalence of colon adenomas is the same in persons with Barrett's oesophagus as in the rest of the population, patients have an increased risk of developing colon cancer. A biologically plausible hypothesis is presented which explains the predisposition to both oesophageal and colon cancers. This hypothesis discusses the contribution of environmental factors such as alcohol, smoking and diet. In addition, it is proposed that the increased expression of the cyclo-oxygenase 2 enzyme is central to the predisposition to both oesophageal and colon cancers. Since this enzyme is inhibited by non-steroidal anti-inflammatory drugs such as aspirin and sulindac, these drugs hold promise as cancer chemopreventive agents in Barrett's oesophagus patients. Sulindac is the most promising of these agents owing to its efficacy in regressing colon polyps in patients with familial adenomatous polyposis

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

We investigated the role of oral infections, dentition and dental X-rays for oral cancer in a north Swedish population. This case-control study consisted of 410 cases with oral cancer for the period 1980-89 and 410 matched controls. All subjects received a mailed questionnaire. The response rates were 96% and 91% for cases and controls, respectively. The univariate analysis showed a statistically significant increased risk for oral cancer among individuals reporting problems with recurrent clinical oral infection (odds ratio (OR) 3.8). Separate analyses were made for groups with a clearly stated HSV-1 infection (OR 1.9) and highly suspected HSV-1 infection (OR 3.3) as reported by the subjects. Odds ratios were also calculated for infections in relation to tobacco and alcohol habits. For individuals reporting recurrent infection problems an increased risk was observed in every combination category. Dental factors such as different fillings, dentures and fixed prostheses showed no increased risks. Dental X-ray did not produce an increased OR either. A multivariate analysis suggested that the most important risk factors were oral infections followed by liquor consumption and active smoking

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The relationship between social class indicators, body mass index (BMI), selected life-style habits (alcohol, coffee, maté and tea drinking) and colorectal cancer was investigated in a case-control study conducted between 1993 and 1997 in Córdoba, Argentina, a relatively high mortality area for colorectal cancer. Cases were 190 patients below age 80 years with incident, histologically confirmed colorectal adenocarcinomas, and controls were 393 patients admitted to hospital for a wide spectrum of acute, non-neoplastic disorders. Higher social class, based on occupation of the head of the household, was significantly associated with colorectal cancer risk: the odds ratios (OR) and 95% confidence intervals (95% CI) were 1.9 (1.2-2.9) for intermediate and 2.0 (1.2-3.4) for the highest as compared to the lowest social class individuals. When compared with subjects whose BMI was<25 kg/m2, the OR was 1.1 (0.7-1.6) for those with BMI 25 to 29 kg/m2, and 1.3 (0.7-2.3) for those ≥ 30. In comparison with alcohol abstainers, the OR was 2.8 (1.6-5.1) for drinkers, and there was a significant trend in risk with dose. The association was observed with wine (the most common alcoholic beverage in Argentina), as well as for beer and spirits. The consumption of coffee, mate and tea was not significantly related to colorectal cancer, but the ORs were below unity (0.9 (0.7-1.3) for coffee, 0.9 (0.6-1.5) for mate and 0.8 (0.6-1.2) for tea drinkers). The relationship between social class, alcohol drinking and colorectal cancer were consistent across strata of sex and age. This study confirms that colorectal cancer has positive social class correlates. The association with alcohol drinking is apparently stronger than previously reported, and may be due to the role of chance and/or peculiar correlates of alcohol drinking in this Argentinean population

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Carcinogens present in cigarette smoke and diet have been associated with pancreatic cancer. We hypothesized that heterocyclic and aromatic amines implicated in these exposures could be involved as causative agents and that therefore genetic variation in enzymes metabolizing these carcinogens could modify the risk of developing malignant and benign pancreatic disease. The effect of the genetic polymorphism of acetyltransferases (NAT1 and NAT2), glutathioneS-transferase Ml (GSTM1) and NAD(P)H: quinone oxidoreductase 1 (NQO1) on the risk of pancreatic diseases (cancer, pancreatitis) was examined in a case—control study. PCR-based assays were used for genotype analysis of genomic DNA from whole blood cells. Samples collected from Caucasian patients with diagnosed pancreatic cancer (n=81), with non-alcoholic (n= 41) and alcoholic pancreatitis (n= 73) and from asymptomatic control subjects (n=78) were analysed. The prevalence of GSTM1 null genotype and of NAT2 fast and slow acetylator genotypes and the distribution of frequencies for NQO1 genotypes did not differ in subjects with pancreatic diseasesvscontrols. For NAT1 slow acetylators a non-significant excess (P=0.18) was found among pancreatic cancer cases vs controls. There was a significant over-representation of the GSTM1 AB or B genotype in all pancreatic disease cases combined (OR=2.6;P<0.05). When concurrent controls were pooled with literature controls (n=1427), OR was 1.4 (P= 0.08). The results of this study, requiring confirmation, suggest that the polymorphism of GSTM1 and NAT1 enzymes may be associated with a modest increase in susceptibility to pancreatic disease

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The occurrence of p53, bcl-2 and heat shock protein (HSP) expression in ovarian tumours was examined and the correlation was investigated between the expression of these proteins and other disease parameters, including FIGO stage, histological subtype, tumour differentiation and steroid hormone receptor status. We analysed p53, bcl-2 and HSP expression in 100 smears of patients with epithelial ovarian carcinomas, 16 smears of patients with borderline malignancy and 20 smears of patients with benign ovarian neoplasms by using immunocytochemical techniques. There were 29 patients with stage I disease, 24 with stage II disease, 40 with stage III disease and seven with stage IV disease according to the FIGO classification. The sensitivities and specificities of bcl-2, p53 and HSP for malignancy were 53% and 40%, 43% and 80%, and 37% and 90%, respectively. HSP was statistically significantly associated with malignant rather than benign tumours. Significant association was also observed between bcl-2 and p53, and p53 and HSP. The association of HSP with malignant tumours is confined to the premenopausal group of patients and in this group by itself there is also a significant association between p53 and malignancy. HSP and p53 were associated with undifferentiated carcinomas, bcl-2 and p53 expression is reduced as disease stage progresses in serous carcinomas and bcl-2 expression is increased as disease progresses in endometrioid carcinomas. There was no significant association between bcl-2 and ER/PR status. In conclusion, HSP has a high specificity for malignant ovarian tumours, bcl-2 and p53 have only moderate to low sensitivity and specificity. Changes in the frequency of bcl- 2 and p53 overexpression between FIGO I and FIGO III stage disease of different ovarian carcinomas indicate a different role of these substances in cellular survival mechanisms in different carcinomas, bcl-2 probably is associated with cell proliferation but not with differentiation

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Effects of synthetic phenolic antioxidants l-O-hexyl-2,3,5-trimethylhydroquinone (HTHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT),tert-butylhydroquinone (TBHQ) and propyl gallate (PG) on 2-amino-3,8-dimethylimidazo[4,5-F]quinoxaline (MelQx)- or activated MelQx-induced mutagenesis and rat hepatocarcinogenesis were compared, and the association between antioxidative activity and inhibition of carcinogenesis was examined. When the antimutagenic activity of five antioxidants against MelQx- or activated MelQx-induced mutagenesis was compared in the Ames assay using the Salmonella strain TA 98, HTHQ showed the greatest effect, followed by BHA, BHT, PG and TBHQ, in that order. In a rat hepatocarcinogenesis study, 6-week-old male F344 rats were given a single ip injection of 200 mg/kg bw of diethylnitrosamine (DEN) and starting 2 weeks later, groups of 15 animals received a diet containing 0.03% MelQx alone, MelQx together with each antioxidant at a dietary dose of 0.25%, each antioxidant alone, or basal diet alone for 6 weeks. Three weeks after the DEN injection, animals were subjected to 2/3 partial hepatectomy. Liver tissues obtained at partial hepatectomy were processed for the measurement of 8-hydroxydeoxyguanine (8-OHdG) and lipid peroxidation. The average number and areas of glutathione 5-transferase placenta! form (GST-P) positive foci were increased by the treatment with MelQx (27.2 ± 6.5 per cm2and 3.17 ± 0.96 mm2/cm2, respectively). A significant decrease in these parameters was found with the simultaneous antioxidant treatment, HTHQ demonstrating the greatest effect, followed by BHA, BHT and TBHQ, and PG. Without MelQx, a weak increase in the number of foci was observed in the BHT treatment case. Examination of 8-OHdG levels in liver DNA, as well as malondialdehyde (MDA) and 4-hydroxyalkenals, did not reveal any inter-group variation. These results indicate that antimutagenic activity of antioxidants against MelQx roughly parallels their anticarcinogenic activity, with HTHQ as the most powerful chemopreventor, but that oxidative stress and antioxidative activity may not be responsible for MelQx-induced hepatocarcinogenesis and its inhibition, respectively

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:1998

数据来源: OVID