ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Of the thousands of chemicals tested, the only compounds found to be potent carcinogens for the oesophagus are the N-nitrosamines. Many of these compounds are readily formed from common precursors in the environment (egexample in food during its storage or preparation) and alsoin vivoin the human stomach. Exposure is therefore likely to be ubiquitous. Although man may be exposed to other oesophageal carcinogens these have yet to be chemically identified, and at present nitrosamines are the sole contenders for the role of initiators of oesophageal cancer in man. Evidence suggests strongly that oesophageal cancer is initiated world-wide by nitrosamines, and promoted by secondary factors, the nature of which varies with the population concerned, notably alcohol in Europe and the USA, dietary deficiencies in China and Iran, mycotoxins in South Africa. When several risk factors coincide in one locality, the result can be a very high incidence of oesophageal cancer, with no one major cause.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

In this necroscopy study the relation between carriage and size of colorectal polyps was correlated with luminal steroid concentrations in respect to malignant risk. Of the 92 subjects entered into the study, 68 had adenomatous polyps of the large bowel, of which 19 had adenomas > 0.9 cm in diameter (large adenomas), 26 in the range 0.5–0.9 cm in diameter (medium adenomas) and 23 of 0.4 cm or less in diameter (small adenomas). Sixty-three percent of subjects carrying large adenomas and 26% of persons carrying small adenomas had an abnormal ratio (> 1.0) of lithocholic acid to deoxycholic acid in intestinal contents as compared to 17% of the adenoma-free comparison group (n= 24). These findings support the suggestion that the ratio of lithocholic acid to deoxycholic acid as a faecal marker may be a useful adjunct to screening procedures for colorectal cancer.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The effect of lactulose on intestinal bacterial metabolism in two identical single-stage chemostats has been studied. The study was designed as a single stage crossover. Both cultures were inoculated and treated in an identical manner except that whilst one fermenter was subject to pH control the other was not and vice versa. Complex bacterial populations were maintained for 23 days and many of the metabolic functions carried out by the micro-organismsin vivowere demonstratedin vitro.The predominant organisms belonged to the generaBacteroides, BifidobaeteriumandClostridiumwith abundant levels of anaerobic Gram-positive rods. The redox potential in each fermenter showed considerable variation with maximum values of below-300 eV being attained. An indication of the stability of the bacterial communities was the production of short-chain volatile fatty acids; during steady-state conditions the mean ratio of the major acids acetic, propionic and butyric being 3.90:0.69:1.00 and 3.65:0.76:1.00 in each fermenter, respectively. During steady-state conditions, 7α-dehydroxylation of the primary bile acid chenodeoxycholic acid was maintained at a constant rate with lithocholic acid representing over 85% of total steroid. Addition of the soluble fibre lactulose to the cultures had a profound effect on many of the parameters tested. Without pH control the culture pH dropped to below 5.0 and this coincided with a substantial decrease in total anaerobes, especiallyBacteroidesspp., an increase inLactobacillusspp. (concomitant with an increase in lactic acid), a decrease in the concentration of short-chain volatile fatty acids and a substantial decrease in 7α-dehydroxylation of chenodeoxycholic acid. These results show that it is possible to maintain viable intestinal bacteriain vitrousing a continuous culture chemostat and that the cultures respond to changing conditions as evinced by the inhibition of 7α-dehydroxylation of chenodeoxycholic acid on addition of lactulose. This indicates that the model may be of further use in studying the modulation of secondary bile acid formation, a possible risk factor in colorectal carcinogenesis.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

In the first part of this study we have shown how the serum levels of four selected tumour markers, namely tissue polypeptide antigen (TPA), carcino-embryonic antigen (CEA), hyaluronic acid (HA) and ferritin, display patterns characteristic of mesothelioma (M) or bronchogenic carcinoma (BC) in asbestos-exposed workers, and we hypothesize that the differences in marker patterns correspond to differences in carcinogenesis mechanisms. In a preliminary study, we found these specific marker patterns in 5/19 exposed workers of whom only one demonstrated any radiological signs of disease. Thus these specific marker patterns may be early events, occurring long (possibly years) before the classical radiological signs of exposure to asbestos. Accordingly they afford an optimal opportunity for prevention which should be adapted to the carcinogenesis mechanism as it is revealed by the marker pattern; it is aimed at antagonizing free radical carcinogenesis in all persons with TPA levels in excess of 100 U/l or Ferritin in excess of 400 ng/ml, and at inhibiting chemical carcinogenesis in those having elevated CEA levels (over 3 ng/ml). The mechanisms involved in these inhibitory processes are described and discussed, as well as the practical implementations that proceed from them. A prevention trial is now being started among 300 active and retired workers of an asbestos-cement works in northern France; the design of the study is presented. This prevention programme should be maintained over many years and holds a strong potential for reducing the untoward effects of exposure to asbestos.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Vitamin supplement histories were taken from a sample of approximately 3,600 individuals (2,461 men and 1,181 women) from a hospital-based population. Multivitamin preparations were the most commonly used vitamin supplements (32% of men, 37% of women) followed by vitamins C (men 11%; women 16%) and E (men 17%; women 23%). The most common combination of supplements among the multi-users was vitamins C and E. Vitamin supplement use was positively associated with education in both sexes. Among women, there was a negative association between vitamin supplement consumption and Quetelet index. No association was found between vitamin use and smoking status or alcohol use or amount of alcohol consumed.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

This study reports the relative risk of death from cancer and from coronary artery disease in 1,811 first-degree relatives of 205 young colorectal cancer probands. The elevation in the risks of death from cancer (eg colon 3.6; rectum 2.0; uterus 1.8; cervix 2.3) is consistent with, though of lower magnitude than previous studies. An unexpected find was a highly significant deficit in coronary deaths. Recently discovered molecular associations between colon cancer and cholesterol metabolism suggest that further family studies of bowel cancer and heart disease in a variety of populations may be worthwhile.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

The purpose of this study was to characterize the epidemiological features of cancer of the penis in Finland. After histological re-examination and exclusions, the final series comprised 269 patients with cancer of the penis diagnosed and reported to the Finnish Cancer Registry between 1955 and 1977. The age-adjusted incidence rate of cancer of the penis decreased slightly from the 1960s onwards and was on the order of 0.5 per 100,000 person-years in the 1970s. Cancer of the penis was a disease of elderly males, which showed no systematic geographical variation in Finland in terms of risk. The most frequent predisposing factors were phimosis, in 44% of the cases, and condylomatous lesions, in 20% of the cases. The general survival (all patients, all stages) was favourable; the 5-, 10-, and 20-year relative survival rates were 71, 69 and 78%, respectively.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Subtypes of oesophageal and gastric cancer in Denmark are compared with respect to their occurrence in men and in women, and in the Danish capital, Copenhagen, versus the rest of Denmark. Three categories of tumours can be distinguished epidemiologically: oesophageal squamous carcinoma, oesophageal and cardial adenocarcinoma, and distal gastric cancer. Comparison of information reported to the Danish Cancer Registry and cause of death as indicated on death certificates suggests that considerable misclassification between subtypes of tumours occurs. The Danish experience supports the findings from other populations of increasing incidence of oesophageal and cardial adenocarcinoma, but because of possible changes in diagnoses over time and of misclassification of subtypes, the data must be interpreted with caution.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Female tumours (iecancers of the female genital tract and breast) represent alone about 40% of new cases and 30% of cancer deaths in Italy (approximately 44,500 new cancer diagnoses and 17,800 deaths in 1991). An attempt to identify major issues in the primary and secondary prevention of these malignancies has disclosed several important points. Firstly, concerning epidemiology, excesses of mortality from cancers of the breast and ovaries exist in the northern part of Italy as compared to the centre and south, whereas mortality rates from uterine cancer are almost equally distributed. However, a tendency towards increasing similarity of various Italian regions emerges. Risk factors most amenable to intervention are overweight, contraceptive methods and dietary habits. Secondly, concerning screening, the number of mammograms (about 552) and the number of Pap smears taken every year (about 4 million) are approximately sufficient to provide a complete coverage of the target subset of the female population as concerns breast and cervical cancer screening. Still, on account of no one carrying out primary call procedures and checks, the actual situation is unsatisfactory. The present article, in addition to quantifying the present status of female cancer prevention in Italy, tries to define a framework for similar exercises in other European countries.

ISSN:0959-8278    

出版商:OVID    

年代:1992

数据来源: OVID