Medical Research Council

About: Medical Research Council is a government organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Malaria. The organization has 16430 authors who have published 19150 publications receiving 1475494 citations.

Nitrosamine-induced carcinogenesis. The alkylation of nucleic acids of the rat by N-methyl-N-nitrosourea, dimethylnitrosamine, dimethyl sulphate and methyl methanesulphonate

Abstract: 1. N[(14)C]-Methyl-N-nitrosourea, [(14)C]dimethylnitrosamine, [(14)C]dimethyl sulphate and [(14)C]methyl methanesulphonate were injected into rats, and nucleic acids were isolated from several organs after various time-intervals. Radioactivity was detected in DNA and RNA, partly in major base components and partly as the methylated base, 7-methylguanine. 2. No 7-methylguanine was detected in liver DNA from normal untreated rats. 3. The specific radioactivity of 7-methylguanine isolated from DNA prepared from rats treated with [(14)C]dimethylnitrosamine was virtually the same as that of the dimethylnitrosamine injected. 4. The degree of methylation of RNA and DNA produced in various organs by each compound was determined, and expressed as a percentage of guanine residues converted into 7-methylguanine. With dimethylnitrosamine both nucleic acids were considerably more highly methylated in the liver (RNA, about 1% of guanine residues methylated; DNA, about 0.6% of guanine residues methylated) than in the other organs. Kidney nucleic acids were methylated to about one-tenth of the extent of those in the liver, lung showed slightly lower values and the other organs only very low values. N-Methyl-N-nitrosourea methylated nucleic acids to about the same extent in all the organs studied, the amount being about the same as that in the kidney after treatment with dimethylnitrosamine. In each case the RNA was more highly methylated than the DNA. Methyl methanesulphonate methylated the nucleic acids in several organs to about the same extent as N-methyl-N-nitrosourea, but the DNA was more highly methylated than the RNA. Dimethyl sulphate, even in toxic doses, gave considerably less methylation than N-methyl-N-nitrosourea in all the organs studied, the greatest methylation being in the brain. 5. The rate of removal of 7-methylguanine from DNA of kidneys from rats treated with dimethylnitrosamine was compared with the rate after treatment of rats with methyl methanesulphonate. No striking difference was found. 6. The results are discussed in connexion with the organ distribution of tumours induced by the compounds under study and in relation to the possible importance of alkylation of cellular components for the induction of cancer.

Nutritional methods in the European Prospective Investigation of Cancer in Norfolk

Abstract: Objective: To describe methods and dietary habits of a large population cohort. Design: Prospective assessment of diet using diet diaries and food-frequency questionnaires, and biomarkers of diet in 24-h urine collections and blood samples. Setting: Free living individuals aged 45 to 75 years living in Norfolk, UK. Subjects: Food and nutrient intake from a food-frequency questionnaire on 23 003 men and women, and from a 7-day diet diary from 2117 men and women. Nitrogen, sodium and potassium excretion was obtained from single 24-h urine samples from 300 individuals in the EPIC cohort. Plasma vitamin C was measured for 20 846 men and women. Results: The food-frequency questionnaire (FFQ) and the food diary were able to determine differences in foods and nutrients between the sexes and were reliable as judged by repeated administrations of each method. Plasma vitamin C was significantly higher in women than men. There were significant OP , 0:001U differences in mean intake of all nutrients measured by the two different methods in women but less so in men. The questionnaire overestimated dairy products and vegetables in both men and women when compared with intakes derived from the diary, but underestimated cereal and meat intake in men. There were some consistent trends with age in food and nutrient intakes assessed by both methods, particularly in men. Correlation coefficients between dietary intake assessed from the diary and excretion of nitrogen and potassium in a single 24-h urine sample ranged from 0.36 to 0.47. Those comparing urine excretion and intake assessed from the FFQ were 0.09 to 0.26. The correlations between plasma vitamin C and dietary intake from the first FFQ, 24-h recall or diary were 0.28, 0.35 and 0.40. Conclusions: EPIC Norfolk is one of the largest epidemiological studies of nutrition in the UK and the largest on which plasma vitamin C has been obtained. Methods for obtaining food and nutrient intake are described in detail. The results shown here for food and nutrient intakes can be compared with results from other population studies utilising different methods of assessing dietary intake. The utility of different methods used in different settings within the main EPIC cohort is described. The FFQ is to be used particularly in pooled analyses of risk from diet in relation to cancer incidence within the larger European EPIC study, where measurement error is more likely to be overcome by large dietary heterogeneity on an international basis. Findings in the UK, where dietary variation between individuals is smaller and hence the need to use a more accurate individual method greater, will be derived from the 7-day diary information on a nested case‐control basis. 24-h recalls can be used in the event that diary information should not be forthcoming from some eventual cases. Combinations of results utilising all dietary methods and biomarkers may also be possible.

Chemotherapy for patients with non-small cell lung cancer: the surgical setting of the Big Lung Trial.

Abstract: Objectives: The non-small cell lung cancer (NSCLC) meta-analysis suggested a survival benefit for cisplatin-based chemotherapy when given in addition to surgery, radical radiotherapy or 'best supportive care'. However, it included many small trials and trials with differing eligibility criteria and chemotherapy regimens. The aim of the Big Lung Trial was therefore to run a large pragmatic trial to confirm the survival benefits seen in the meta-analysis. Methods: In the surgery setting, a total of 381 patients were randomised to chemotherapy (C, 192 patients) or no chemotherapy (NoC, 189 patients). C was three 3-weekly cycles of cisplatin/vindesine, mitomycin/ifosfamide/cisplatin, mitomycin/vinblastine/cisplatin or vinorelbine/cisplatin. Results: Chemotherapy was given before surgery in 3% of patients whilst 97% received adjuvant chemotherapy. Baseline characteristics were: median age 61 years, 69% male, 48% squamous cell, 93% WHO PS 0-1, 27% stage I, 38% stage II, and 34% stage III. Complete resection was achieved in approximately 95% of patients. In the C group, 13% received no chemotherapy, 21% one or two cycles, and 64% all three cycles of their prescribed chemotherapy (60% of the latter with no delays or modification). 30% had grade 3/4 toxicity, mainly haematological, nausea/vomiting and neutropenic fever, and six patients were reported as having a treatment-related death. 198 (52%) of patients have died, but there is currently no evidence of a benefit in overall survival to the C group: HR 1.02 (95% CI 0.77-1.35), P = 0.90). Conclusions: This trial has failed to observe a survival benefit with adjuvant chemotherapy following complete resection of stage I-III NSCLC. However, the hazard ratio and 95% confidence intervals are consistent with the previously reported meta-analysis and two large recently reported trials, which suggest a small survival benefit with cisplatin-based.

Dementia in western Europe: epidemiological evidence and implications for policy making.

Abstract: Summary Dementia is receiving increasing attention from governments and politicians. Epidemiological research based on western European populations done 20 years ago provided key initial evidence for dementia policy making, but these estimates are now out of date because of changes in life expectancy, living conditions, and health profiles. To assess whether dementia occurrence has changed during the past 20–30 years, investigators of five different studies done in western Europe (Sweden [Stockholm and Gothenburg], the Netherlands [Rotterdam], the UK [England], and Spain [Zaragoza]) have compared dementia occurrence using consistent research methods between two timepoints in well-defined geographical areas. Findings from four of the five studies showed non-significant changes in overall dementia occurrence. The only significant reduction in overall prevalence was found in the study done in the UK, powered and designed explicitly from its outset to detect change across generations (decrease in prevalence of 22%; p=0·003). Findings from the study done in Zaragoza (Spain) showed a significant reduction in dementia prevalence in men (43%; p=0·0002). The studies estimating incidence done in Stockholm and Rotterdam reported non-significant reductions. Such reductions could be the outcomes from earlier population-level investments such as improved education and living conditions, and better prevention and treatment of vascular and chronic conditions. This evidence suggests that attention to optimum health early in life might benefit cognitive health late in life. Policy planning and future research should be balanced across primary (policies reducing risk and increasing cognitive reserve), secondary (early detection and screening), and tertiary (once dementia is present) prevention. Each has their place, but upstream primary prevention has the largest effect on reduction of later dementia occurrence and disability.