ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Several taxonomically distinct human pathogenic viruses capable of upholding persistent infections have been recognized as important carcinogens. Jointly they are characterized by going into decade-long interactions with host cells and or tissues. Tumours arise after a long latent period in a few infected individuals. The cellular changes necessary for malignancy are only in part directly or indirectly caused by virus-cell interactions. Cofactors are assumed to be involved. The different routes to malignancy reflect the distinct strategies of each virus in its interaction with the host, which for the upkeep of chronic infections requires a tight control of both virus and cell multiplication and the extent to which an immune response is provoked. The size of the virus-cancer problem and the possibility of prevention makes virology one of the most promising areas of cancer prevention on a global scale. A much wider use of the vaccination against hepatitis B, especially in children, is warranted in developed countries.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

There is an increased incidence of childhood cancer, particularly lymphocytic neoplasia, in children who live dose to nuclear installations. Possible causes are radiation-induced germ line mutations in occupationally exposed parents, or radiation-induced somatic mutation in the developing cells of the fetus or child due to increased environmental exposure. An alternative possibility is that the socioeconomic characteristics of the communities lead to an altered response to infection in childhood and this increases the risk of lymphocytic neoplasia hi particular. For sites other than Sellafield in the UK, the evidence linking childhood cancer to radiation is unconvincing and it is possible that the increase is entirely due to the social characteristics of the communities. In Seascale, a village close to Sellafield, however, the increase is more marked and it is unlikely that social factors alone can explain the change. Furthermore, the environmental discharges from Sellafield are much higher than from other sites, and approach levels which could have a measurable effect on cancer incidence. In spite of a great deal of epidemiological investigation, no clear answer is available. It is argued that in order to solve the problem we must use new knowledge from molecular genetics and measure the rate of somatic mutation in those who work in the nuclear industry and in those who live nearby.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A literature search examined 39 reports on the relationship between the absence of endocervical cells in a cervical smear and the sampling technique used. Using (pooled) ratios we compared the results for different pairs of sampling devices, thereby controlling for the design of each study when appropriate. The Cytobrush appears the most efficient sampling method with regard to the presence of endocervical cells. Combining the results of this review with the results of a previous meta-analysis on the effect of the sampling technique on the detection of pathology, the combined spatula and Cytobrush technique seems to be the best sampling method.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The question of how much effective progress against cancer is being made has been raised repeatedly during the last decade; one approach to evaluating such progress is represented by the analysis of mortality, which has been used by several researchers. Here we report mortality trends for 1970–90 for four age-groups, calculated for each 3-year period, and presented as the percentage change of the rate of the first period examined. Detailed graphs for each country and for the European Community as a whole are presented for ‘all cancers’, and for cancer of the colon-rectum, lung, breast and ovary. For other cancers (stomach, melanoma, uterus, testis and Hodgkin's disease), the graphs are presented only for the whole of the European Community. Variations in mortality are discussed, in terms of changes in incidence, efficacy and diffusion of prevention, as well as improvement in diagnosis and treatment.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Levels (μg/g dry weight) of cadmium (Cd), zinc (Zn) and copper (Cu) were determined in kidneys with renal cell carcinoma from 20 male and 11 female patients. Autopsied kidneys from nine males and eight females who had died of nonmalignant diseases were used as controls. The mean levels in cortex of Cd was in cases 103.2 and in controls 79.9 (not significantly different). For non-smoking cases, mean level of Cd in cortex was somewhat lower than in the controls. No significant differences were found between cases and controls for Cd levels in the medulla. Zn in cortex was significantly lower in the cases aged ≥ 69 years (mean 182.0) than in the corresponding controls (mean 237.6). Zn in medulla was significantly lower in all cases (mean 103.5) than in controls (mean 162.2). The mean level of Cu in the medulla in cases was 10.7 and in controls 13.0 (P= 0.05). No differences were found for Cu levels in cortex.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Soil samples were collected during certain years for the period 1982–89 from high-and low-risk areas for oesophageal cancer in Transkei, southern Africa. These samples were taken either from cultivated soils under maize monoculture, or from uncultivated soils (1989 only) adjacent to the maize fields. Analyses of mineral dements in the soil samples were performed at two independent laboratories. Furthermore, soil and maize leaf samples, from field trials in a high-and a low-risk area for oesophageal cancer were analysed. The results from this study do not agree with those reported previously for Transkei. Cultivated soils in both high-and low-risk areas were found to be highly fertile. The levels of Mn, Ni, Mg, Ca, K and soil pH were significantly higher, and Al, Fe and organic matter significantly lower in the high-risk compared with the low-risk area. Leaf analysis, although not tested statistically, indicated higher levels of Mn K, Ca and Fe, and lower levels of P, in the high-risk area.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Genetic changes are important in the development of colorectal cancer. Ploidy and rectal mucosal proliferation were measured in histological normal rectal mucosa of 85 individuals (mean age 59 years, range 29–74) who had a total colonoscopy. Fifty-one subjects had an adenoma or were undergoing adenoma surveillance. Twenty-two subjects had a strong family history of colorectal cancer and 12 individuals comprised a control group who had a normal colonoscopy without a family history of colorectal cancer. An abnormal DNA content (aneuploidy) was found in the normal mucosa of nine (10.6%) individuals. There was no significant difference in rectal mucosal proliferation with those who had aneuploidy and those who had diploid. There was a trend towards increased proliferation in those with aneuploidy and adenomas, compared with controls. Of the 35 individuals undergoing adenoma surveillance, eight had recurrent adenomas, and three of these expressed aneuploidy. In the other 27, in whom no adenomas were found, no individual expressed aneuploidy (P = 0.01, Fisher's exact test). Aneuploidy within histological normal mucosa is an unusual feature, which requires further investigation, particularly in patients developing adenomas.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Several clinical trials have demonstrated the efficacy as chemopreventive agents on upper aerodigestive tract (UADT) cancer of vitamin A or its natural precursor, β-carotene, or its synthetic analogues, retinoids. Particularly, 13-cis-retinoic acid (cRA) has been shown to reverse oral leukoplakia and to reduce the frequency of second primary tumours in patients treated for head and neck cancer. Since chemopreventive treatments must be of very long-term duration (even years), and because of apparent ‘good health’ of treated patients, the toxicity of used drugs and the compliance with treatment need to be carefully considered. Current clinical research has evaluated the efficacy of low doses of cRA in larger numbers of patients, and the increased effectiveness of cRA when used in combination with recombinant alpha-interferon 2a (r-α-IFN 2a) has also produced high objective response rate in patients affected with squamous cell carcinoma of the head and neck.In vitroandin vivostudies to verify the validity of several biomarkers (in particular micronuclei) as intermediate end-points in chemoprevention studies are continuing, to allow the short-term screening of promising chemopreventive drugs to be used in clinical trials. The published literature on this matter is reviewed, with special attention to retinoid treatment and toxicity/compliance-related problems, and compared with our own experience.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

It is well documented that environmental pollution from industrial activity, sewage farms, hazardous waste sites, incinerators, etc, contributes to the overall cancer risk and that this contribution can be considerable under certain circumstances. It is important, therefore, to identify the level of genotoxic activity in the environment and to relate it to biomarkers of cancer risk in humans. After reviewing a range of cytogenetic assays, we have selected theTradescantiamicronucleus assay (TRAD-MCN) developed by Maet alto be used in indoor and field evaluations. The meiotic pollen mother cells of T clone 4430 are particularly sensitive to chemical pollutants; the buds are exposed for 6–8 h. We describe assays made down wind from a coal-fired power station and from the vicinity of two waste sites. Statistically significant results were obtained at 200 m and 600 m down wind from the power station; higher levels of micronucleus frequencies (MN) were found in foggy rather than dry conditions. Similarly, in the vicinity of two waste sites the MN frequencies were significantly increased in both dry and foggy conditions up to 1.5 km down wind; this was despite previous efforts to rehabilitate the sites. The TRAD-MCN assay is sensitive, reproducible, easy to perform, well standardized, inexpensive and undemanding in equipment. We propose that it be the primary test for genotoxicity evaluation and mapping followed, in suspicious areas, by human biomarker assays.

ISSN:0959-8278    

出版商:OVID    

年代:1994

数据来源: OVID