1.
A prospective study of meat and meat mutagens and prostate cancer risk.
Cross, AJ, Peters, U, Kirsh, VA, Andriole, GL, Reding, D, Hayes, RB, Sinha, R
Cancer research. 2005;65(24):11779-84
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Plain language summary
Meat cooked at high temperatures is a source of carcinogens (heterocyclic amines and polycyclic aromatic hydrocarbons). The formation of these substances depends on the meat type, and is highest in meats cooked by high-temperature cooking methods. The aim of the study was to determine whether meat intake or meat-related mutagens was associated with increased prostate cancer risk. This was a prospective cohort study of 29,361 men aged between 55 and 74. Results show that a consumption of more than 10 g per day of very well done meat was associated with a 42% increased risk for prostate cancer and a 69% increased risk for incident disease. A high intake of the carcinogens under study was associated with a 22% increased risk for prostate cancer and a 28% increased risk for incident disease. The study concluded that there is a positive association between prostate cancer risk and a high intake of very well done meat.
Abstract
High-temperature cooked meat contains heterocyclic amines, including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and polycyclic aromatic hydrocarbons, such as benzo(a)pyrene (BaP). In rodents, a high intake of PhIP induces prostate tumors. We prospectively investigated the association between meat and meat mutagens, specifically PhIP, and prostate cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Diet was assessed using a 137-item food frequency questionnaire and a detailed meat-cooking questionnaire linked to a database for BaP and the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-b]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx), and PhIP. During follow-up, we ascertained a total of 1,338 prostate cancer cases among 29,361 men; of these, 868 were incident cases (diagnosed after the first year of follow-up) and 520 were advanced cases (stage III or IV or a Gleason score of > or =7). Total, red, or white meat intake was not associated with prostate cancer risk. More than 10 g/d of very well done meat, compared with no consumption, was associated with a 1.4-fold increased risk of prostate cancer [95% confidence interval (95% CI), 1.05-1.92] and a 1.7-fold increased risk (95% CI, 1.19-2.40) of incident disease. Although there was no association with MeIQx and DiMeIQx, the highest quintile of PhIP was associated with a 1.2-fold increased risk of prostate cancer (95% CI, 1.01-1.48) and a 1.3-fold increased risk of incident disease (95% CI, 1.01-1.61). In conclusion, very well done meat was positively associated with prostate cancer risk. In addition, this study lends epidemiologic support to the animal studies, which have implicated PhIP as a prostate carcinogen.
2.
Partial purification and characterization of extrinsic pathway inhibitor (the factor Xa-dependent plasma inhibitor of factor VIIa/tissue factor).
Warn-Cramer, BJ, Maki, SL, Zivelin, A, Rapaport, SI
Thrombosis research. 1987;48(1):11-22
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Plain language summary
Green tea (GT) consumption has been associated with the prevention and control of type 2 diabetes, cardiovascular and metabolic disease as well as having a positive effect on body weight and composition. However, the polyphenols in GT have been shown to interact with mineral distribution within the body and those minerals have been shown to be deficient in obesity. Studies to measure mineral status in obese subjects supplementing with GT have been inconclusive and this study aimed to measure the serum concentrations of minerals (calcium, copper, iron, zinc, magnesium), body mass index, total antioxidant status (TAS), lipid profile and glucose concentration. 46 obese patients were randomised into 2 groups, one group were supplemented with 279mg of green tea extract (GTE) and 208mg of the polyphenol epigallocatechin-3-gallate (EGCG) and the other group were issued with a placebo for 3 months. The study concluded that GTE improved Zn and Mg, however decreased levels of FE. The results confirmed a positive effect on body mass, lipid profile, glucose and TAS. It was concluded that more studies are required on a larger population over a longer period of time.
Abstract
We report a procedure to purify partially from plasma (approximately 1200 fold) the factor Xa-dependent inhibitor of factor VIIa/tissue factor (i.e., the extrinsic pathway inhibitor or EPI) and describe some of its properties. An assay for EPI was developed based upon inhibition of factor VIIa/tissue factor induced release of activation peptide from tritiated factor IX by a test sample in the presence but not in the absence of factor Xa. Approximately 50% of the total EPI activity in plasma was found in the lipoprotein fraction, which was used as the starting material for purification. Total lipoproteins (isolated by density ultracentrifugation) were delipidated and the urea soluble apoproteins gel filtered on Sephacryl S-200. The inhibitory activity co-eluted with the major protein peak, which primarily contained apoprotein A-I. Inhibitory activity was separated from apoprotein A-I by anion-exchange chromatography on Q-Sepharose and was further resolved from higher and lower molecular weight contaminating proteins by polypreparative disc gel electrophoresis in the presence of 0.1% SDS. Functional inhibitory activity eluted from the polypreparative disc gel in two discrete pools of different molecular weights (approximately 34,000 and approximately 43,000 D). Apoprotein E was identified by immunological techniques as the major protein present in both of these pools. However, incubation with a monospecific polyclonal antibody to human apoprotein E did not decrease EPI activity either in plasma or in the partially purified polypreparative disc gel fractions. A rabbit antiserum was prepared against material from the polypreparative disc gel. The IgG fraction neutralized approximately 95% of the total inhibitory activity present in plasma. Therefore, EPI in the lipoprotein fraction and in the non-lipoprotein fraction of plasma appears to be antigenically similar.