ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The assessment of physical activity is one of the most important methodological issues in research into physical activity and cancer risk. A sedentary Western lifestyle has been observed to influence biological mechanisms promoting development of certain types of cancer. At present the totality of evidence supports a protective effect against cancers of the colon and probably the breast, while further data concerning carcinoma of other cancers are required. Thus, physical activity represents a powerful public health measure for reducing cancer risk. Studies of the association between physical activity and cancer risk have used a great variety of methods, but have most often included work and/or leisure time activity. Questionnaires are the method most often used and various components of physical activity such as type, frequency, intensity and lifetime physical activity have been recorded. However, the measurements used when assessing physical activity have been hampered by lack of accuracy as regards validity and reliability, missing information on the various components of physical activity and sparse information of lifetime exposure, and often no repeat assessments in cohort studies. Discrepancies between studies elaborating the association between physical activity and site-specific cancer risk may be explained through real differences or lack of information on the various components of physical activity (type, intensity, duration) and incomplete information about the cancer type studied (localization, histological type). The complicated nature of the variable physical activity, combined with incomplete understanding of the pathogenesis of most cancer and lack of knowledge regarding possible biological mechanisms operating between physical activity and cancer, warrants further studies. In these studies methodological improvements in measuring physical activity, combined with inclusion of physiological markers (heart rate, energy balance, hormonal levels, etc.) reflecting the variety of physical activities performed are of particular interest. Assessing biomarkers and intermediate steps for site-specific cancer risk may give us further insight into the relation between physical activity and cancer that will be of enormous interest for public health recommendations.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Lung cancer is one of major public health problems facing the world today, owing to the high incidence of the disease and its poor prognosis. Although the principal cause of lung cancer is tobacco use, smokers find it extremely difficult to quit the habit. Hence, there is a need to take action targeted at other risk factors for this disease. One such factor is diet, which is known to be able to raise or lower the risk of lung cancer. This paper seeks to complement other reviews in the field and to shed more light both on the influence that dietary factors may have upon the occurrence of this neoplasm and on the causes of this possible effect.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

A case–control study in the population of the Eastern Black Sea region of Turkey was conducted to learn the incidence of stomach cancer in the siblings of patients with gastric carcinoma. Among 1240 patients with gastric carcinoma, 168 had sibling(s) with a history of stomach cancer versus 19 cases in the control group matched according to age and gender (OR 10.07,P < 0.0001). The frequency of a history of stomach cancers and cancer of other organs in first- to third-degree relatives was 60.7% and 38.0%, respectively, of 168 sibling cases with gastric carcinoma (P < 0.0001). Fifty-two point three percent of sibling cases having a history of cancer in other organs in their relatives also reported stomach cancer in the same-degree relatives. The number of stomach cancers in the first- to third-degree relatives of sibling cases was higher than the number of other organ cancers in the same-degree relatives (P < 0.01). Familial clustering of stomach cancer was reported in 12.5% of sibling cases. The study of stomach cancer history in the siblings suggests: the presence of a genetic susceptibility, high risk of the disease occurrence in the siblings of patients, higher predisposition to gastric than to other organ cancers in the relatives, and not infrequent familial clustering.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

To assess how the risk of cancer of the colon and rectum relates to place of birth and socio-economic status, we analysed data from an Italian case–control study. Data included 1225 cases with a recent diagnosis of cancer of the colon (ages 19–74 years), 728 cases of cancer of the rectum (ages 23–74 years) and 4154 controls (ages 19–74 years), frequency-matched with cases by age and catchment area and admitted to hospitals for a wide spectrum of acute non-neoplastic conditions. Compared with residents born in the north of Italy, migrants from the centre and south had an odds ratio (OR) of 0.7 (95% CI 0.5–0.9) for colon cancer and OR of 0.9 (95% CI 0.7–1.2) for cancer of the rectum. The inverse association of migration with colon cancer was stronger among women (OR 0.5, 95% CI 0.4–0.8) than among men (OR 0.8, 95% CI 0.6–1.1), and was independent of education and occupation. Among migrants, the direct association between education and colon cancer risk was less clear than among non-migrants. In conclusion, place of origin played an independent role in colon cancer aetiology. Results on rectal cancer were less clear, although in the same direction. Among migrants, those less susceptible to behavioural changes (e.g. women) retained most of the benefit associated with their place of origin.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Gallbladder cancer is a common malignancy among women in India. The aetiology of gallbladder carcinoma is still obscure and although numerous factors have been implicated, none has stood the test of time. This study was carried out to evaluate the role of lipid peroxidation product 4‐hydroxynonenal (HNE) in gallbladder carcinogenesis. High‐performance liquid chromatography (HPLC) analysis was carried out in 30 bile samples obtained during laparotomy from patients with gallbladder cancer (n = 10), cholelithiasis (n = 10) and age‐ and sex‐matched controls (n = 10). A significantly high concentration of HNE and lower concentration of biliary pH and electrolyte was observed in patients with carcinoma of the gallbladder compared with controls and patients with cholelithiasis. A significant correlation was also observed between biliary Na+and K+(r = 0.72), biliary Ca2+and Na+(r = 0.69) among controls. However, there was no correlation between HNE, electrolytes and pH among cancer patients. An increased concentration of biliary HNE and decreased concentration of electrolytes suggest biliary stasis rather then increased peroxidation in cancer patients.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Low gastric juice total vitamin C concentration in the presence ofHelicobacter pyloriinfection probably plays a role in gastric carcinogenesis. Vitamin C plays a role in the neutralization of various pathogenic factors connected withH. pyloriinfection, including the destruction of free radicals, which damage tissues and cell DNA, and inhibition of the formation ofN-nitroso compounds, which have a strong carcinogenic activity. The aim of the study was to determine whether tobacco smoking had any effect on gastric juice vitamin C concentration in healthy subjects and in patients infected withH. pylori. Eighty-six patients with dyspeptic symptoms undergoing routine endoscopy entered the study after giving informed consent. In all patients plasma and gastric juice total vitamin C levels were measured by a spectrophotometric method. They were entered into four groups: group I (controls) –H. pylori-negative non-smokers (n = 17), group II –H. pylori-negative smokers (n = 16), group III – non-smokers withH. pyloriinfection (n = 21), and group IV –H. pylori-infected smokers (n = 32). In the control group (I) the mean gastric juice total vitamin C concentration was 17.1 μg/ml (range 5.3–40.0 μg/ml), which was significantly higher (P 0.05) than in group II (12.6 μg/ml, range 5.1–21.0 μg/ml), group III (5.8 μg/ml range 2.1–13.7 μg/ml) and group IV (3.9 μg/ml, range 1.1–10.6 μg/ml) (P 0.001). Statistically significant differences also were noted between groups II and III (P 0.01) and groups II and IV (P 0.001) and between groups III and IV (P 0.05). These results demonstrate that the concentration of vitamin C in gastric juice is significantly lower in smokers than in non-smokers. This was observed in healthy subjects as well asH. pylori-infected patients. This phenomenon may be one of the mechanisms whereby smoking contributes to the production of gastric lesions, impairs healing of peptic ulcers and also increases the recurrence rate of peptic ulcers in cases withH. pyloriinfection.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Typically, cancer is caused by the interaction of genetic and environmental factors. In colorectal carcinogenesis, diet and nutritional habits are the most important external risk determinants. Allelic polymorphisms of certain metabolizing enzymes may have an influence on cancer risk by modifying the concentration of active carcinogenic compounds in the body. In the present study we investigated the interaction between nutritional and genetic susceptibility factors in human colon carcinogenesis. Healthy volunteers were divided into four groups, based on allelic polymorphisms ofN-acetyltransferase 2 and glutathione-S-transferase M1 enzymes. Comet assay was used to determine the level of DNA strand breaks in exfoliated colorectal mucosal cells, following a 2-day vegetarian diet, and after switching to a 2-day ‘high-meat’ diet. The ‘high-meat’ diet statistically significantly increased the amount of single-strand breaks in rapid acetylators and among individuals with a GSMT1+ genotype, while it caused only a slight and not significant increase in the other groups. Our study emphasizes the importance of using susceptibility markers in cancer epidemiology, since environmental effects are strongly modified by these genetic factors.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The study aimed at probing the possible role of human papillomavirus (HPV) infection in squamous cell carcinomas of the upper aerodigestive tract, with a special reference to tonsillar cancer. We used the Swedish Family Cancer Database to analyse second cancers in the upper aerodigestive tract of women first diagnosed with in-situ or invasive cervical cancer. First cancers of their husbands were also analysed. Standardized incidence ratios (SIRs) were calculated for female and male cancers, adjusted for age at diagnosis, period, sex, socio-economic status and residential area. Among women, increases were observed at many sites, but tonsillar cancers were increased only among women aged 50 years or more at diagnosis of in-situ cervical cancer (SIR 2.58). The increases at these sites are probably ascribed to the effects HPV, smoking, alcohol or their interaction. Husbands of cervical cancer patients developed an excess (SIR over 2.00) of both tonsillar cancer (SIR 2.39 when wife with in-situ cancer and SIR 2.72 when wife with invasive cervical cancer) and cancer of the tongue. The excess of tonsillar cancer among husbands of women with HPV-associated neoplastic lesions of the cervix supports the a priori hypothesis that HPV may be involved in tonsillar carcinogenesis.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID