The oligosaccharide α-cyclodextrin has modest effects to slow gastric emptying and modify the glycaemic response to sucrose in healthy older adults

In healthy older subjects, the glycaemic response to carbohydrate-containing meals is dependent on gastric emptying and intestinal absorption; when the latter is slowed, the magnitude of the rise in glucose is attenuated. The oligosaccharide α-cyclodextrin has been reported to diminish the glycaemic response to starch in young adults; this effect has been attributed to the inhibition of pancreatic amylase. We examined the effects of α-cyclodextrin on gastric emptying of, and the glycaemic and insulinaemic responses to, oral sucrose in healthy older subjects; as sucrose is hydrolysed by intestinal disaccharides, any effect(s) of α-cyclodextrin would not be attributable to amylase inhibition. A total of ten subjects (seven males and three females, age 68-76 years) were studied on 2 d. Gastric emptying, blood glucose and serum insulin were measured after ingestion of a 300 ml drink containing 100 g sucrose, labelled with (99m)Tc-sulphur colloid, with or without 10 g α-cyclodextrin. Gastric emptying was slowed slightly by α-cyclodextrin; this effect was evident between 135 and 195 min and was associated with a slight increase (P < 0·05) in distal stomach retention. After α-cyclodextrin, blood glucose was slightly less (P < 0·05) at 60 min, and serum insulin was less (P < 0·0005) at 90 and 120 min. There was no difference in the incremental areas under the curve (iAUC) for blood glucose, but there was a trend for the iAUC for serum insulin to be lower (P = 0·09) after α-cyclodextrin. We conclude that in a dose of 10 g, α-cyclodextrin has modest effects to slow gastric emptying of, and modify the glycaemic and insulinaemic responses to, oral sucrose, probably due to delayed intestinal carbohydrate absorption.     

Does vitamin C intake slow the progression of gastric cancer in Helicobacter pylori-infected populations?

Vitamin C's role in the prevention of disease and malignancy has been studied over the last several decades. Vitamin C intake has been shown to have an inverse relationship with gastric cancer. Recent follow-up studies on high-risk populations suggest that ascorbic acid, the reduced form of vitamin C, protects against gastric cancer, for which H. pylori is a significant risk factor. In populations infected with H. pylori, there is a reduction in gastric juice ascorbic acid concentration. This article reviews the risk factors for gastric cancer and the role of vitamin C in prevention of the disease.     

Is gastric ulceration different in normal and malnourished rats?

Protein malnutrition can adversely affect all tissues. The aim of the present study was to test the hypothesis that protein deprivation influences gastric ulcer formation, as well as metabolism and organ growth, in rats. In the present study, there was a significant reduction in the body and organ weight of rats fed a low-protein diet (P<0.001). Malnourished rats were less susceptible to ulceration of the gastric mucosa in ethanol and indomethacin models of acute gastric ulcers when compared with rats fed a normoproteic diet (17 % protein). Mucus production and prostaglandin E2 formation increased in malnourished rats, possibly explaining the lower number of acute ulcers in these animals. Pylorus ligature altered gastric juice composition (increased pH and gastric volume, and decreased total acid concentration) in the animal group fed a low-protein diet compared with the group fed a diet containing 17 % protein (P<0.05). The gastric mucosa was more damaged in malnourished rats than in normal rats evaluated for 14 d after acetic acid injection (P<0.001). Malnourished rats exhibited resistance to acute gastric lesions, owing to an increase in prostaglandin GE2 release and mucus secretion, which protected their gastric mucosa. This phenomenon was not seen in subchronic gastric ulceration.     

Does calcium in drinking water modify the association between nitrate in drinking water and risk of death from colon cancer?

The objective of this study was to explore whether calcium (Ca) levels in drinking water modified the effects of nitrate on colon cancer risk. A matched case–control study was used to investigate the relationship between the risk of death from colon cancer and exposure to nitrate in drinking water in Taiwan. All colon cancer deaths of Taiwan residents from 2003 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth and year of death. Information on the levels of nitrate-nitrogen (NO₃-N) and Ca in drinking water have been collected from Taiwan Water Supply Corporation (TWSC). The municipality of residence for cases and controls was assumed to be the source of the subject's NO₃-N and Ca exposure via drinking water. We observed evidence of an interaction between drinking water NO₃-N and Ca intake via drinking water. This is the first study to report effect modification by Ca intake from drinking water on the association between NO₃-N exposure and risk of colon cancer mortality.     

Does smoking or alcohol modify the risk of Epstein-Barr virus-positive or -negative Hodgkin lymphoma?

BACKGROUND: The aim was to investigate whether 2 subgroups of Hodgkin lymphoma (Epstein-Barr virus-positive and Epstein-Barr virus-negative) are associated with smoking or alcohol. METHODS: Patients with lymphoma diagnosed between age 16 and 69 years in geographically defined areas of England were recruited between 1998 and 2003. One control, matched to each lymphoma case on sex, date of birth, and area of residence, was randomly selected from population registers. Self-reported histories of tobacco and alcohol use were collected during face-to-face interviews with cases and controls. RESULTS: Compared with lifelong nonsmokers, ever-smokers were at increased risk of Hodgkin lymphoma (odds ratio =1.4; 95% confidence interval = 1.1-1.9). This excess was among current smokers, defined as smoking 2 years before diagnosis (1.7; 1.2-2.3). An increasing trend was observed with rising numbers of years smoked. Risks fell as the number of years stopped smoking increased, becoming equivalent to that of a nonsmoker 10 or more years after quitting. Associations were suggested for Epstein-Barr virus-positive Hodgkin lymphoma, but less so for Epstein-Barr negative Hodgkin lymphoma. No associations between Hodgkin lymphoma and alcohol consumption were observed. CONCLUSIONS: The association between smoking and Hodgkin lymphoma in general, and Epstein-Barr-positive Hodgkin lymphoma in particular, is consistent with previous studies. Further exploration of the relationship between Hodgkin lymphoma and smoking and of the potential mechanisms by which smoking could interact with Epstein-Barr virus status to increase Hodgkin lymphoma risk are required.     

Does particulate matter modify the association between temperature and cardiorespiratory diseases?

BACKGROUND: A number of studies have shown that both temperature and air pollution are associated with health outcomes. In assessing air pollution effects, temperature is usually considered a confounder. However, only a few recent studies considered air pollution as confounders while assessing temperature effects. Few studies are available on whether or not air pollution modifies the temperature-disease relationship. METHODS: In this study, we used three parallel Poisson generalized additive models to examine whether particulate matter < 10 mum in aerodynamic diameter (PM10) modified the effects of minimum temperature on cardiorespiratory morbidity and mortality in Brisbane, Australia. RESULTS: Results show that PM10 statistically significantly modified the effects of temperature on respiratory and cardiovascular hospital admissions, all nonexternal-cause mortality, and cardiovascular mortality at different lags. The enhanced adverse temperature effects were found at higher levels of PM10, but no clear evidence emerged for interactive effects on respiratory and cardiovascular emergency visits. Three parallel models produced similar results, which strengthened the validity of findings. CONCLUSION: We conclude that it is important to evaluate the modification role of air pollution in the assessment of temperature-related health impacts.     

Does percutaneous endoscopic gastrostomy prevent gastro-oesophageal reflux during the enteral feeding of elderly patients?

Percutaneous endoscopic gastrostomy (PEG) is reported to be a safe method for enteral feeding, although its ability to prevent gastro-oesophageal reflux (GOR) during enteral feeding remains controversial. In 12 elderly patients fed enterally to avoid the risk of tracheal aspiration, we have compared two 24-h oesophageal pH profiles, one recorded when enteral feeding was delivered at first via a nasogastric tube (NGT), and the other via a PEG. The second recording was always performed at least 8 days after gastrostomy placement. Enteral nutrition consisted of 500 ml of a polymeric diet delivered 3 times a day at 08:00, 13:00 and 18:00. After gastrostomy placement, enteral feeding was associated with a pathological acid reflux in 8 out of 12 patients. In all of these 8 patients, GOR was mostly related to a high number of reflux episodes. In 4 out of 8 patients, GOR occurred only during the 3 h following the administration of the nutritive diet. In 4 of the patients, GOR did not occur any more after removal of the NGT, whilst gastrostomy placement was followed by GOR in 5 patients. GOR during enteral feeding via PEG is common in elderly subjects. We have shown that a chronological relationship existed in some patients between the endoscopic procedure and the onset of a pathological GOR.     

Does acute glutamine depletion enhance the response of glutamine synthesis to fasting in muscle in adult and old rats?

BACKGROUND AND AIMS: In earlier studies, skeletal muscle glutamine synthetase (GS) activity was shown to be enhanced by fasting and glucocorticoids, and inhibited by exogenous glutamine (Gln) supplementation. The current study was designed to determine whether phenylbutyrate (PhiB), a Gln-chelating agent in humans, (1) could trap Gln and produce a decline in plasma Gln in rats, as it does in humans, and (2) if so, whether (Phi)B would further enhance the response of muscle GS activity to fasting in rats. METHODS: Adult (6-8 months) and aged (20-21 months) rats were fasted for 5 days and received two doses of 0.5 g(Phi)Bby orogastric route at times 0 and 4 h, and were then sacrificed at 5.5 h. Plasma Gln was measured by enzymatic methods, other amino acids were quantified by amino acid analysis. GS activity was measured in soleus (SO) and tibialis anterior (TA) muscles. RESULTS: (Phi)B treatment was associated with: (1) a 20% decline in plasma Gln concentration from 572+/-54 to 424+/-34 micromol/L (P<0.05) and from 476+/-49 to 360+/-80 micromol/L (P<0.05) in fasted adult and old rats, respectively; and (2) a preservation of GS up-regulation by fasting in TA and SO muscles in both adult and aged rats, with TA muscle GS activities of 198+/-65 vs. 203+/-68 ((Phi)B-treated vs. vehicle-treated, NS), and 244+/-81 vs. 274+/-59 (NS) nmol/h/mg protein in adult and aged rats, respectively. CONCLUSION: These data suggest that: (1) large doses of (Phi)B deplete plasma Gln in fasted rats, regardless of age, (2) Gln depletion induced by Phi)B does not alter GS activity.     

Does income inequality modify the association between air pollution and health?

BACKGROUND: It has been hypothesized that socioeconomic status may act as an effect modifier of the association between air pollution and health. In this study, we investigated whether income inequality may modify the association between fine particulate pollution and self-reported health. METHODS: We combined several different sources of data. Demographic and socio-economic data, at the individual level, were drawn from the 2001 US Behavioral Risk Factor Surveillance System (BRFSS). County-level particulate pollution data for the year 2001 were provided by the US Environmental Protection Agency. State-level income inequality was measured by the Gini index using US census data from the year 2000. We used a hierarchical logistic regression to model the association between general self-reported health and fine particulate pollution accounting for income inequality as an effect modifier and controlling for the usual confounders. RESULTS: We found that when income inequality is low (10th percentile of the Gini distribution), the odds of reporting fair or poor health for a 10microg/m3 increase in particulate pollution is 1.34 (95% confidence interval 1.21-1.48). The analogous odds ratio for higher income inequality (60th percentile of the Gini distribution) is 1.11 (95% confidence interval 1.06-1.16). CONCLUSIONS: Income inequality was found to be an effect modifier of the association between general self-reported health and particulate pollution. However, these findings challenged our hypothesis that people living in higher income inequality areas are more vulnerable to the impact of air pollution. We discuss the factors driving these results.     

Does influence at work modify the relation between high occupational physical activity and risk of heart disease in women?

Purpose

To investigate whether influence at work modifies the association between demanding and strenuous occupational physical activity (OPA) and risk of ischaemic heart disease (IHD).

Methods

A sample of 12,093 nurses aged 45–64 years from the Danish Nurse Cohort Study was followed for 20.6 years by individual linkage to incident IHD in the Danish National Patient Registry. Information on OPA, influence at work, other occupational factors and known risk factors for IHD was collected by self-report in 1993.

Results

During follow-up 869 nurses were hospitalised with incident IHD. Nurses exposed to strenuous OPA and low influence at work had a 46% increased risk of IHD [hazard ratio (HR) 1.46 (95% confidence interval (CI) 1.02–2.09)] compared to the reference group of nurses with moderate OPA and high influence at work. Nurses exposed to strenuous OPA and high influence at work were not at an increased risk of IHD [HR 1.10 (95% CI 0.59–2.06)]. An additive hazards model showed there were 18.0 (95% CI ?0.01 to 36.0) additional cases of IHD per 10,000 person years among nurses with strenuous OPA and low influence at work compared to nurses with moderate OPA and high influence at work. A detrimental additive interaction between strenuous OPA and low influence at work that could explain the additional cases of IHD among nurses with strenuous OPA and low influence at work was indicated.

Conclusion

The findings suggest that high influence at work may buffer some of the adverse effects of strenuous OPA on risk of IHD.

     

Does Use of the Calendar in Surveys Reduce Heaping?

This study examines heaping of reported durations of three postpartum variables in five countries based on two methods of data collection in retrospective surveys. Two Demographic and Health Surveys were conducted for each of the countries, one that used a five-year month-by-month calendar to record the durations and a subsequent survey in which duration information was collected from simple questions in the body of the questionnaire. Heaping indexes were calculated for breastfeeding, amenorrhea, and abstinence at six, 12, 18, and 24 months postpartum. Use of the calendar was associated with a significant reduction in the proportion of heaped responses for both breastfeeding and amenorrhea, and the effect increased for longer durations. To obtain more accurate information about these variables, the authors recommend the use of the calendar.     

Does food restriction increase life span in lean rats?

The effect of food restriction on survival of lean animals was investigated using WAG/Rij rats. In this strain, body weight of males and females fed ad libitum reached a plateau of 350 g and 220 g, respectively, at the age of 10 months. Their spontaneous food intake was 15 g per 24 h in males and 10 g in females, values which were 50 to 40 % lower than that reported for most strain of laboratory rats. A 30 % food restriction was initiated at the age of 10 months in both gender, and also at 20 months in males. In females, reduction in caloric intake had no effect on mean survival until 30 months, but change the slope of the survival curve in the last part of life. As a result, mean and maximal life span were increased by 10 %. In males, when reduction in food intake was initiated at 10 months, the survival curve of the restricted animals was shift to the right, also corresponding to a 10 % increase in mean and maximal survival, without change in the slope of mortality curve. When started at 20 months, diet restriction has no significant effect on survival of male rats. It was concluded that food restriction initiated in adults is mostly efficient to increase survival in rodents with large spontaneous food intake, but have a minor effect on lean strain, although it has beneficial effect on several aging processes.