Lactobacillus rhamnosus strain GG prevents enterohemorrhagic Escherichia coli O157:H7-induced changes in epithelial barrier function.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 intimately attaches to intestinal epithelial monolayers and produces attaching and effacing (A/E) lesions. In addition, EHEC infection causes disruptions of intercellular tight junctions, leading to clinical sequelae that include acute diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome. Current therapy remains supportive since antibiotic therapy increases the risk of systemic complications. This study focused on the potential therapeutic effect of an alternative form of therapy, probiotic Lactobacillus rhamnosus strain GG, to attenuate EHEC-induced changes in paracellular permeability in polarized MDCK-I and T84 epithelial cell monolayers. Changes in epithelial cell morphology, electrical resistance, dextran permeability, and distribution and expression of claudin-1 and ZO-1 were assessed using phase-contrast, immunofluorescence, and transmission electron microscopy and macromolecular flux. This study demonstrated that pretreatment of polarized MDCK-I and T84 cells with the probiotic L. rhamnosus GG reduced morphological changes and diminished the number of A/E lesions induced in response to EHEC O157:H7 infection. With probiotic pretreatment there was corresponding attenuation of the EHEC-induced drop in electrical resistance and the increase in barrier permeability assays. In addition, L. rhamnosus GG protected epithelial monolayers against EHEC-induced redistribution of the claudin-1 and ZO-1 tight junction proteins. In contrast to the effects seen with the live probiotic, heat-inactivated L. rhamnosus GG had no effect on EHEC binding and A/E lesion formation or on disruption of the barrier function. Collectively, these findings provide in vitro evidence that treatment with the probiotic L. rhamnosus strain GG could prove to be an effective management treatment for preventing injury of the epithelial cell barrier induced by A/E bacterial enteropathogens.

Efficiency and utilization of various energy sources for growth.

The efficiency of energy utilization by animals during growth is influenced by a number of factors including composition of the diet and sex and strain of the animal. Net energy efficiency is "the proportion of total energy intake [that] is not lost in the stool, urine, or as diet-induced heat losses (specific dynamic action) and, thus, is available for obligate energy demands (basal metabolic rate), for physical work, and for storage (or growth)". In studies reporting an increased efficiency in the utilization of energy from fat than from equal amounts of energy from carbohydrate, this increased efficiency is indicated by less energy lost by the animal as heat and more energy retained in the carcass of the animal as fat. Because the energy yield from nutrients and the efficiency of energy utilization appear to differ under various conditions, energy intakes using the Atwater values cannot be assumed to be physiologically equivalent in providing energy to the animal during growth.

Body mass index and the prevalence of hypertension and dyslipidemia.

OBJECTIVE: To describe and evaluate relationships between body mass index (BMI) and blood pressure, cholesterol, high-density lipoprotein-cholesterol (HDL-C), and hypertension and dyslipidemia. RESEARCH METHODS AND PROCEDURES: A national survey of adults in the United States that included measurement of height, weight, blood pressure, and lipids (National Health and Nutrition Examination Survey III 1988-1994). Crude age-adjusted, age-specific means and proportions, and multivariate odds ratios that quantify the association between hypertension or dyslipidemia and BMI, controlling for race/ethnicity, education, and smoking habits are presented. RESULTS: More than one-half of the adult population is overweight (BMI of 25 to 29.9) or obese (BMI of > or =30). The prevalence of high blood pressure and mean levels of systolic and diastolic blood pressure increased as BMI increased at ages younger than 60 years. The prevalence of high blood cholesterol and mean levels of cholesterol were higher at BMI levels over 25 rather than below 25 but did not increase consistently with increasing BMI above 25. Rates of low HDL-C increased and mean levels of HDL-C decreased as levels of BMI increased. The associations of BMI with high blood pressure and abnormal lipids were statistically significant after controlling for age, race or ethnicity, education, and smoking; odds ratios were highest at ages 20 to 39 but most trends were apparent at older ages. Within BMI categories, hypertension was more prevalent and HDL-C levels were higher in black than white or Mexican American men and women. DISCUSSION: These data quantify the strong associations of BMI with hypertension and abnormal lipids. They are consistent with the national emphasis on prevention and control of overweight and obesity and indicate that blood pressure and cholesterol measurement and control are especially important for overweight and obese people.