Dietary patterns and the risk of colorectal adenoma recurrence in a European intervention trial

The relations between individual foods and nutrients to colorectal tumours are conflicting. Few studies have taken into account the interdependence between individual components of diet and their possible interactions. The aim of the study was to examine the associations between dietary patterns and the risk of colorectal adenoma recurrence in the European fibre-calcium intervention trial. Among the 640 patients with confirmed adenomas at the index colonoscopy, 592 had an initial dietary assessment using a diet history questionnaire. The present analysis was restricted to 277 men and 165 women without history of adenoma prior to the index colonoscopy and who completed the study. The main end point was the 3-year recurrence of adenomas. Principal component analysis was used to identify dietary patterns from 50 food groups. Ninety-two patients presented new colorectal adenomas at the 3-year colonoscopy (65 men and 27 women). In men, three meaningful dietary patterns emerged from analysis, explaining 21.3% of variability. They were called 'Mediterranean', 'Sweets and snacks' and 'High fat and proteins' patterns. None of them were significantly related to the overall recurrence of colorectal adenomas either in univariate or multivariate analyses. Among women, the 'Mediterranean', the 'Western' and the 'Snacks' patterns explained 21.9% of variability. The 'Mediterranean' pattern characterized by a high consumption of olive oil, vegetables, fruit, fish and lean meat significantly reduced adenoma recurrence [second tertile: adjusted odds ratio (OR)=0.50, 95% confidence interval (CI)=0.18-1.42; third tertile: adjusted OR=0.30, 95% CI=0.09-0.98; P for linear trend=0.04]. The 'Western' and 'Snacks' patterns were not associated with recurrence among women. In conclusion, this study suggests that the Mediterranean dietary pattern may reduce the recurrence of colorectal adenomas, at least in women. These exploratory results need to be confirmed by larger studies.

Overweight and colorectal cancer risk

Epidemiological studies on risk factors for colorectal cancer have focused mainly on diet. Weight and height have also been studied, partly because they reflect the balance between energy intake and expenditure in different age periods. Energy intake, body size, physical activity and colorectal cancer risk will be reviewed in this paper focusing mostly on recent data coming from Italian, English and Scandinavian studies. Overweight has long been recognised as a risk factor for hormone related and other cancers, including colorectal cancer. In addition, the epidemiological evidence consistently shows that physical activity reduces the risk of colon cancer. On the contrary, evidence on rectal cancer is less impressive. In conclusion, body size control along all life and physical activity represent important factors to prevent colon cancer and a wide range of chronic conditions. Therefore, strategies to favour these goals through counselling from health-care providers, regulatory changes, and programs aimed at individuals and communities should be implemented.

Energy intake, overweight, physical exercise and colorectal cancer risk

Epidemiological studies on risk factors for CRC have focused mainly on diet. In any case, the results of these studies show several inconsistencies, except for the beneficial role of high intake of vegetables and, to some lesser extent, of fruit. Weight and height have also been studied, partly because they reflect the balance between energy intake and expenditure in different age periods. Energy intake, body size and physical activity will be reviewed in this paper focusing mostly on recent data coming from Italian, English and Scandinavian studies. Overweight has long been recognized as a risk factor for hormone related and other cancers and this is confirmed not simply from case-control studies but from large cohort studies as well. The major findings of recent Italian studies are that excessive weight at various ages predicts colorectal cancer risk in men while in women, abdominal obesity, as indicated by a high WHR, represents a more reliable risk indicator. If all men could reduce their BMI below 25, about 9% of male colorectal cancer might be avoided in Italy. A decrease of WHR below 0.82 might reduce colorectal cancer in women by 19%. In addition, the epidemiological evidence consistently shows that physical activity reduces the risk of colon cancer. On the contrary, evidence on rectal cancer is less impressive. Some uncertainty still exists in relation to the intensity and duration of physical activity. In conclusion, body size control along all life and physical activity represent important factors to prevent colon cancer and a wide range of chronic conditions. Therefore, strategies to favour these goals through counselling from health-care providers, regulatory changes and programs aimed at individuals and communities should be implemented.

Rectal carcinoma: preoperative staging and detection of postoperative local recurrence with transrectal and transvaginal ultrasound

Transrectal ultrasound (TRUS) was performed preoperatively in 35 patients with rectal carcinoma and the results were compared to histologic findings. In the same group, postoperative studies were performed in 22 patients; in women, transvaginal ultrasound (TVUS) was added to the transrectal study. According to Duke's classification modified by Astler-Coller, in relation to the "T" parameter, TRUS correctly staged 33 of 35 neoplasms (accuracy, 94.3%); one was overstaged and one was understaged. In detection of lymph node involvement, accuracy was 74% (sensitivity 69%, specificity 73.9%). Recurrent local tumors, histologically confirmed, developed in two of 22 postoperative patients who had undergone curative anterior resection. This study demonstrates that TRUS is an accurate method in preoperative staging of rectal carcinoma. In the prospective study, the role of follow-up TRUS and TVUS in detection of local recurrences is evaluated.

Effect of covalent dimer conjugates of angiotensin II on receptor affinity and activity in vitro

Angiotensin II [1-8 or 2-8] analogues and [4-8] fragments were dimerized through the amino- or carboxy-terminal groups in order to try to increase their potency as reported for other hormones. The binding affinity to the angiotensin II receptor subtypes A (A IIA) and B (A IIB) was tested and compared to the potency in rabbit aortic ring. The [2-8] dimers coupled through the N-terminus show no significant change in potency in aortic ring. The [4-8] fragments coupled through the N-terminus are inactive in the ring. They have however a significantly increased affinity for the A IIA receptor, the specific function of which has not yet been reported. When angiotensin II analogues or fragments are coupled through the C-terminus, there was a significant drop in affinity and potency, confirming the importance of the free carboxyl group in position 8 for binding and activity. It is concluded that binding to the A IIB receptor correlates well with the effectiveness in aortic ring. However, in contrast to the beneficial effect reported for a large number of other hormones, dimerization of angiotensin II or its fragments is not accompanied by an increased biological activity in aortic ring.

Synthetic C3a analogs as specific inhibitors of C3a activity

Various C3a-related C-terminal synthetic oligopeptides were investigated for their ability to induce a release of serotonin from guinea pig platelets. The results confirm earlier findings that expression of biological C3a activity requires the four to five C-terminal amino acids of the C3a primary structure and underlines the essential role of the C-terminal arginine. Besides their ability to induce a specific release reaction, these peptides--after short incubation with the platelets--lead to a specific desensitization of the cells for C3a or C3a-related stimuli. Expression of this inhibitory activity required concentrations of the peptides more than 100-fold lower than those that were necessary to induce secretion. The possibility of using C3a analogs as specific inhibitors for C3a offers a valuable tool for in vivo studies of biological C3a activity.