Analysis of the effects of food and of digestive secretions on the small intestine of the rat. 1. Mucosal morphology and epithelial replacement.
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A modified Roux-en-Y repositioning of rat small intestine was performed so that the proximal segment of bowel (A) received only bile and pancreastic secretions, the second (B) received food direct from the stomach, and these two segments drained into a third (C). Four to five weeks after operation, cell production was assessed by injection of vincristine into operated, sham-operated and unoperated rats, and counts of blocked metaphases were made on isolated microdissected crypts. Villus height, crypt depth, and the number of crypts per villus (crypt/villus ratio) were also measured. Most of segment A showed no significant differences from sham-operated intestine, although the normal proximo-distal gradient of villus height was abolished. At the distal end (near the anastomosis with segments B and C), crypt depth and cell production were increased. The villus height gradient in segment B was also abolished, although crypt depth and cell production were significantly increased, especially at the proximal end. Crypt/villus ratio was also increased. Segment C showed all the characteristics of small bowel promoted to a more proximal position: increased villus height, crypt depth and cell production. Increased crypt/villus ratio was also observed. These results are discussed in terms of the role of food and of digestive secretions in the control of mucosal morphology and epithelial replacement. (+info)
Post-ingestive feedbacks and associative learning regulate the intake of unsuitable sterols in a generalist grasshopper.
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Behavioural studies of the grasshopper Schistocerca americana were undertaken to identify the mechanisms that regulate the intake of dietary sterols. In the first experiment, grasshoppers were allowed to feed on spinach, a plant containing only unsuitable sterols; immediately after this first meal, a suitable or unsuitable sterol was injected into the haemolymph. Grasshoppers injected with unsuitable sterols had second meals on spinach that were significantly shorter than those of grasshoppers injected with suitable sterols, indicating that unsuitable dietary sterols are detected post-ingestively. In the second experiment, grasshoppers were fed food containing only unsuitable sterols and were then presented with glass-fibre discs containing different concentrations of a suitable sterol or sucrose only (the control). The results suggest that grasshoppers do not use a direct feedback operating on mouthpart chemoreceptors to regulate their intake of suitable sterols. In the third experiment, grasshoppers were presented with artificial diets containing different sterols and flavours, and feeding was observed over a sequence of meals. The results from both the first and last experiments suggest a role for associative learning in regulating the intake of unsuitable sterols. (+info)
Muscarinic blockade inhibits gastric emptying of mixed-nutrient meal: effects of weight and gender.
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We compared the vagal contribution to gastric emptying in lean and obese subjects by monitoring gastric emptying of a meal during muscarinic blockade. Lean (n = 6) and obese subjects (n = 6) underwent two treatments: 1) saline infusion and 2) atropine infusion [0.4 mg/m2 bolus, 0.4 mg. (m2)-1. h-1] for 2 h, initiated 30 min before ingestion of a 600-kcal breakfast (64% carbohydrate, 23% fat, 13% protein) composed of orange juice (labeled with Indium-111), egg sandwich (labeled with Technetium-99m), cereal, milk, and banana. Anterior and posterior images were taken every 90 s for 90 min using a dual-headed camera. Atropine significantly delayed emptying of both solid (P < 0.007) and liquid (P < 0.002). Obese subjects exhibited a greater delay in liquid emptying during muscarinic blockade compared with lean subjects (P < 0.02). Female subjects exhibited a slower rate of gastric emptying and were less sensitive to atropine. These data suggest that obese subjects exhibit altered gastric cholinergic activity compared with lean subjects and that gender differences in gastric emptying rate may be due to differences in autonomic tone. (+info)
Needs assessment following hurricane Georges--Dominican Republic, 1998.
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Hurricane Georges struck the Carribean Islands in September 1998, causing numerous deaths and extensive damage throughout the region. The Dominican Republic was hardest hit, with approximately 300 deaths; extensive infrastructure damage; and severe agricultural losses, including staple crops of rice, plantain, and cassava. Two months after the hurricane, the American Red Cross (ARC) was asked to provide food to an estimated 170,000 families affected by the storm throughout the country. To assist in directing relief efforts, CDC performed a needs assessment to estimate the food and water availability, sanitation, and medical needs of the hurricane-affected population. This report summarizes the results of that assessment, which indicate that, 2 months after the disaster, 40% of selected families had insufficient food > or =5 days per and 28% of families reported someone in need of medical attention. (+info)
Abbreviated measures of food sufficiency validly estimate the food security level of poor households: measuring household food security.
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This study was designed to develop an abbreviated method that captures both the qualitative and quantitative dimensions of household food security (HFS). Women in poor and very poor households (n = 238) in a peri-urban barrio in Caracas, Venezuela, provided data on food availability and their perception of food resource constraints and hunger experiences within the home. Socioeconomic data and food-related behavior that may predict HFS levels were gathered. On average, the top 12 food contributors of energy provided 81% and predicted more than 90% of the variation in households' total energy availability using stepwise regression analysis. On the other hand, a 4-point 12-item scale was shown to have face, content and construct validity with reiterative testing, factor analysis and a Chronbach's alpha coefficient of 0.92. Assessing predictors of energy availability together with a self-perceived HFS scale may provide a valid and reliable method for identifying and monitoring food security levels among poor urban households. (+info)
Food safety training for nutritionists.
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A course on food safety for nutritionists has been developed in Indonesia through collaboration between government, industry, academia and international agencies. By teaching the basic principles of the subject it equips the participants to recommend foods that are safe as well as nutritious. (+info)
Dietary determinants of colorectal proliferation in the normal mucosa of subjects with previous colon adenomas.
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Dietary determinants of colorectal mucosa proliferation were studied in 69 subjects previously operated for at least two sporadic colon adenomas. Information on recent dietary habits was collected by a validated food frequency questionnaire, and proliferation was measured by [3H]thymidine incorporation in colorectal biopsies by determining the labeling index (LI) and the percentage of LI in the upper part of the crypt, two parameters that are increased in subjects at high risk of colon cancer. The LI was significantly higher in women as compared with men (P = 0.01). Diet showed several associations with colorectal mucosa proliferation: (a) subjects in the highest tertile of fish consumption had a significantly lower LI (P = 0.0013) compared with those in the lower tertiles [5.20 +/- 1.87 versus 6.80 +/- 2.18 (mean +/- SD)]; (b) subjects with a low red meat consumption had lower proliferation in the upper part of the crypt [2.38 +/- 2.10, 5.30 +/- 4.62, and 5.89 +/- 4.82 in the low, middle, and high tertile of consumption, respectively (mean +/- SD); P = 0.0093]; (c) according to estimated nutrient intakes, the LI was lower in subjects reporting a high intake of starch (P = 0.006) and higher in subjects with a low intake of beta-carotene (P = 0.002). The results show that subjects reporting a diet rich in fish, starch, and beta-carotene and low in red meat had lower colorectal mucosa proliferation and a normal pattern of proliferation along the crypt. Given the correlation between colorectal proliferative activity and colon cancer risk, such a dietary pattern might be beneficial for subjects at high risk of colon cancer. (+info)
Food groups and colorectal cancer risk.
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Most studies of diet and colorectal cancer have considered nutrients and micronutrients, but the role of foods or food groups remains open to debate. To elucidate the issue, we examined data from a case-control study conducted between 1992 and 1997 in the Swiss canton of Vaud. Cases were 223 patients (142 men, 81 women) with incident, histologically confirmed colon (n= 119) or rectal (n= 104) cancer (median age 63 years), linked with the Cancer Registry of the Swiss Canton of Vaud, and controls were 491 subjects (211 men, 280 women, median age 58 years) admitted to the same university hospital for a wide spectrum of acute non-neoplastic conditions unrelated to long-term modifications of diet. Odds ratios (OR) were obtained after allowance for age, sex, education, smoking, alcohol, body mass index, physical activity and total energy intake. Significant associations were observed for refined grain (OR = 1.32 for an increase of one serving per day), and red meat (OR = 1.54), pork and processed meat (OR = 1.27), alcohol (OR = 1.28), and significant protections for whole grain (OR = 0.85), raw (OR = 0.85) and cooked vegetables (OR = 0.69), citrus (OR = 0.86) and other fruits (OR = 0.85), and for coffee (OR = 0.73). Garlic was also protective (OR = 0.32 for the highest tertile of intake). These findings in a central European population support the hypothesis that a diet rich in refined grains and red meat increases the risk of colorectal cancer; they, therefore, support the recommendation to substitute whole grains for refined grain, to limit meat intake, and to increase fruit and vegetable consumption. (+info)