Microbial source tracking in highly vulnerable karst drinking water resources.

Water resources situated in areas with underlying karst geology are particularly vulnerable to fecal pollution. In such vulnerable systems, microbial source tracking (MST) methods are useful tools to elucidate the pathways of both animal and human fecal pollution, leading to more accurate water use risk assessments. Here, we describe the application of a MST toolbox using both culture-dependent bacteriophage and molecular-dependent 16S rRNA assays at spring and well sites in the karstic St Imier Valley, Switzerland. Culture-dependent and molecular-dependent marker performance varied significantly, with the 16S rRNA assays displaying greater sensitivity than their phage counterpart; HF183 was the best performing human wastewater-associated marker while Rum2Bac was the best performing ruminant marker. Differences were observed in pollution regimes between the well and spring sampling sites, with the spring water being more degraded than the well site. Our results inform the choice of marker selection for MST studies and highlight differences in microbial water quality between well and spring karst sites.

The effects of high altitude trekking on body composition and resting metabolic rate.

Resting metabolic rate (RMR) and body composition were evaluated in 12 healthy volunteers before and after 16 days of high altitude trekking and climbing. RMR was measured by indirect calorimetry and body composition by electrical impedance. A 29% reduction in energy intake during high altitude exposure was observed. Fat mass loss averaged about 2.2 kg (p < 0.05) and lean body mass about 1.1 kg, which was almost significant (p = 0.07). As expected, estimated RMR at the end of the expedition--calculated by predictive formulae including body fat and lean body mass as covariates--was significantly reduced by 119 kcal/day as a consequence of the reduction in body weight. Measured RMR values, on the contrary, did not show any significant decline. In conclusion our study showed that high altitude trekking induced a weight loss due approximately 2/3rds to fat mass and 1/3rd to lean body mass. Decreased energy efficiency, which was still present several days after returning to sea level, may have helped contribute to weight loss due to reduced energy intake.

Effect of altitude on body composition during mountaineering expeditions: interrelationships with changes in dietary habits.

Loss of body weight occurs during high mountain expeditions but whether it is due to inadequate diet or other factors is unknown. Moreover the composition of the weight loss is unclear. The aim of our study was to compare the nutritional, anthropometric and metabolic changes during a mountaineering expedition in two groups of climbers, whose dietary energy intake was ad libitum, one given a lacto-fish-ovo-vegetarian diet and one an omnivorous diet. The intake of various nutrients, body weight, body composition and metabolic variables were evaluated before and during high altitude exposure and after the return to low altitude. The two groups were matched for age, body mass index and gender. No significant differences were found for nutritional variables between the two groups. Energy, animal and vegetable protein and fiber intake were significantly lower at climbing quote than before the beginning of the expedition. Significant differences between before the beginning and base camp in all variables were found. Energy and animal protein intake, but not vegetable protein and fiber intake, were significantly lower at climbing quote than at base camp. All subjects significantly reduced body weight, body mass index, waist and hip circumferences but not fat-free mass and fat mass. Metabolic variables significantly improved after the mountaineering expedition. Our study seems to confirm that a mountaineering expedition decreases energy and protein intake, reduces body weight and improves metabolic variables. Because our subjects spontaneously tended to have the same food intake despite the different dietary recommendations, our study failed to observe any differences between the two groups. However, our study shows that a low protein diet, in which the type of protein is mostly vegetable protein, could be adapted for climbers determining only a small decrease of fat-free mass.

Interrelationships between intraabdominal fat and total serum testosterone levels in obese women.

Thirty-six women aged 18 to 52 years with body mass indexes (BMIs) between 27 and 52 were studied. Visceral and subcutaneous fat areas and body fat were evaluated by computerized tomography with a single scan at the IV-V lumbar vertebra level. Glucose, insulin, and C-peptide levels were measured before and after a glucose load. Total and free serum testosterone and 24-hour urinary cortisol excretion were measured. A stepwise multiple regression equation showed the visceral to subcutaneous fat area ratio to be the most powerful predictor for glucose alterations both during fasting and after a glucose load, and showed BMI to be the most powerful predictor for insulin and C-peptide levels. Total serum testosterone, after matching for age and BMI, demonstrates a significant negative correlation with visceral fat area. We conclude that in obese women, as in men, intraabdominal fat negatively correlates with serum testosterone levels.

Total and intra-abdominal fat measurements by ultrasound and computerized tomography.

Computerized tomography, a method of proven reliability for direct measurement of both total and visceral body fat, is not widely usable and alternative means of assessing body fat are required. Several anthropometric parameters, including ultrasound measurements of intra-abdominal and subcutaneous fat, were considered in 119 females (age 15-72 years, body mass index 24-51 kg/m2). Computerized tomography was also performed for total and visceral fat areas at the L4-L5 level. Reliability of each of these measurements in predicting total fat was assessed. Tertiles for visceral fat area were calculated (< 114, 114-170, > 170 cm2). Only ultrasound intra-abdominal fat measurements were able to distinguish between all three VAT groups (16 +/- 10, 32 +/- 13, 50 +/- 22 mm); neither sagittal diameter nor waist/hip girth ratio were able to distinguish between the two > 114 cm2 groups. Predictive equations for total adipose tissue area confirmed weight/height ratio as the best predictor of total fat. Ultrasound intra-abdominal thickness was the 1 degree variable to enter the stepwise regression in predictive equations for visceral adipose tissue area. The 2 degrees was age, the 3 degrees sagittal diameter, the 4 degrees waist/hip girth ratio and the 5 degrees ultrasound subcutaneous abdominal thickness (adjusted r2 = 0.784; P < 0.001).

Alcohol consumption, smoking habits and body fat distribution in Italian men and women aged 20-60 years.

The study was performed on 601 patients (294 males and 307 females) of a general practitioner. Alcohol intake and smoking habits were compared with other anthropometric measurements including waist-to-hip girth ratio. Patients were divided into non-smokers and smokers (subdivided into three groups according to the number of cigarettes smoked per day) and into non-drinkers and drinkers (subdivided into three groups with different alcohol intakes). Ex-smokers were excluded from the study. Analysis of covariance using age, body mass index, physical activity and menopausal status as covariates, showed that: (1) cigarette smoking is not accompanied by a specific pattern for body fat distribution; (2) waist-to-hip ratio was significantly different for the four classes of alcohol intake for women (non-drinkers: 0.809, < 11 g: 0.805, 11-20 g: 0.809, > 20 g: 0.826; F = 2.8, P < 0.05) but not for men (non-drinkers: 0.944, < 20 g: 0.934, 21-40 g: 0.940, > 40 g: 0.943; F = 0.9); (3) increased alcohol intake corresponds to an increased lipid and energy supply.

Resting metabolic rate, body-fat distribution, and visceral fat in obese women.

Resting metabolic rate (RMR) was evaluated in 27 obese women aged 16-49 y [body mass index (in kg/m2) 27-51] by indirect calorimetry. Visceral and subcutaneous adipose tissue areas, body fat, and fat-free mass (FFM) were measured by a single scan with computed tomography (CT); the waist-hip circumference ratio (W/H) was also used. Comparison between the lowest and the highest RMR quartiles--adjusted for age and FFM--revealed a higher W/H in the highest quartile (0.78 +/- 0.08 vs 0.88 +/- 0.08; P < 0.05). No difference was observed in CT indexes. No differences in W/H were observed after RMR was adjusted for age, FFM, and body fat. Our results point out that RMR, adjusted for FFM and age, correlates with body-fat distribution as evaluated by W/H, but not with visceral fat, as evaluated by CT. Correlations disappeared after RMR was adjusted for body fat as well.

Evaluation of regional body fat distribution: comparison between W/H ratio and computed tomography in obese women.

Measurements of regional body fat distribution as determined by waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio were compared in 63 obese women. Subjects were divided into three CT-evaluated tertiles on the basis of visceral-to-subcutaneous adipose tissue ratio (group I, 0.05-0.231; group II, 0.232-0.344; group III, 0.345-0.781). The three groups showed no appreciable differences in body weight, body mass index or total abdominal adipose tissue. Waist-to-hip ratio values were significantly lower in group I than in groups II and III. There was no statistically significant difference between groups II and III. Visceral abdominal adipose tissue was significantly and progressively higher in the three groups. Subcutaneous abdominal adipose tissue was significantly lower in group III than in group I. All metabolic variables and systolic and diastolic blood pressure were higher when visceral-to-subcutaneous adipose tissue ratio cut-off values were increased. Waist-to-hip ratio was significantly correlated with total adipose tissue, body mass index, visceral abdominal adipose tissue and subcutaneous abdominal adipose tissue. Visceral-to-subcutaneous adipose tissue ratio was correlated with visceral abdominal adipose tissue (r = 0.84, P < 0.01) and subcutaneous abdominal adipose tissue (r = -0.28, P < 0.05). There was no correlation between visceral-to-subcutaneous adipose tissue ratio and body mass index or total abdominal adipose tissue. Visceral-to-subcutaneous adipose correlated more closely with metabolic variables than did waist-to-hip ratio. Partial correlations between waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio and metabolic variables, adjusted for body mass index, showed statistically significant relationships for visceral-to-subcutaneous adipose tissue ratio, but not for waist-to-hip ratio. Visceral-to-subcutaneous adipose tissue ratio correlated with waist-to-hip ratio in the study population as a whole, but only in group I did the correlation between visceral-to-subcutaneous adipose tissue ratio and waist-to-hip ratio prove statistically significant. The present study demonstrates that visceral-to-subcutaneous adipose tissue ratio is a better index of body fat distribution than waist-to-hip ratio.

Body fat distribution in pre- and post-menopausal women: metabolic and anthropometric variables and their inter-relationships.

The aim of the study was to compare body fat distribution and metabolic variables in pre- and post-menopausal women. Body fat distribution was measured using abdominal circumference and computerized tomography. No significant differences were found between the two groups as regards body weight, body mass index, waist-hip ratio and total abdominal adipose tissue areas. Subcutaneous abdominal adipose tissue areas were significantly higher in premenopausal women whereas visceral abdominal adipose tissue areas and the subcutaneous to visceral abdominal adipose tissue area ratios were significantly higher in post-menopausal subjects. After adjusting for body mass index, no significant differences emerged between the two groups as regards total abdominal adipose tissue areas, waist circumference, hip circumference and waist-hip circumference ratio; subcutaneous abdominal adipose tissue areas were significantly lower and both visceral abdominal adipose tissue areas and visceral to subcutaneous abdominal adipose tissue area ratios significantly higher in post-menopausal women (P less than 0.01). Basal glucose, sum of blood glucose values during oral glucose tolerance test and blood cholesterol values were significantly higher in the post-menopausal group (P less than 0.05), while no significant difference was observed in sum of blood insulin values during oral glucose tolerance test. Basal plasma insulin values, systolic blood pressure and diastolic blood pressure were higher in post-menopausal women, though the differences were not significant. Only blood cholesterol was significantly higher in post-menopausal women after adjusting for visceral abdominal adipose tissue areas. Positive correlations emerged between age and waist-hip ratio (P less than 0.05), visceral abdominal adipose tissue areas and the visceral to subcutaneous abdominal adipose tissue area ratio (P less than 0.001). A negative correlation was established between age and subcutaneous abdominal adipose tissue areas (P less than 0.01). There was a significant correlation between visceral abdominal adipose tissue areas and metabolic and haemodynamic variables in both pre- and post-menopausal women. In pre-menopausal women, body mass index correlated with basal glucose, basal insulin, sum of glucose during oral glucose tolerance test and systolic and diastolic blood pressure (P less than 0.05). When stepwise multiple regression analysis was used to evaluate the joint effect of anthropometric variables on metabolic variables, visceral abdominal adipose tissue area proved to be the most powerful variable for predicting metabolic disorders. Our data suggest that visceral abdominal adipose tissue areas and visceral to subcutaneous abdominal adipose tissue area ratios increase with age. Obesity correlates directly with the amount of subcutaneous fat, but not with the distribution pattern.(ABSTRACT TRUNCATED AT 400 WORDS)

Sonography detection of small intra-abdominal fat variations.

The aim of this study was to check the reliability of sonography in measuring small variations in quantities of subcutaneous and intra-abdominal fat. Twenty-six obese women (BMI 39 +/- 6) underwent a 15 day very low calorie diet. The study included, both before and after very low calorie diet, computed tomography measurements of total (AT), visceral (VAT) and subcutaneous (SAT) adipose tissue areas, visceral/subcutaneous area ratio (V/S), waist/hip circumference ratio measurements (W/H), and ultrasound measurements of abdominal subcutaneous skin-muscle thickness, intra-abdominal muscle-aorta thickness and intra-abdominal/subcutaneous thickness ratio. Weight reduction was from 101 +/- 17 to 95 +/- 16 kg (P less than 0.001). W/H dropped from 0.83 +/- 0.06 to 0.82 +/- 0.07 (n.s.). VAT dropped from 158 +/- 72 to 134 +/- 61 cm2 (P less than 0.005), SAT from 572 +/- 151 to 566 +/- 164 cm2 (n.s.) and V/S from 0.29 +/- 0.15 to 0.25 +/- 0.11 (P less than 0.01). Abdominal subcutaneous fat thickness decreased from 36 +/- 8 to 35 +/- 10 mm (n.s.), intra-abdominal thickness from 39 +/- 25 to 20 +/- 20 mm (P less than 0.001) and intra-abdominal/subcutaneous from 1.1 +/- 0.7 to 0.8 +/- 0.6 (P less than 0.005). VAT measurement accurately identified small intra-abdominal fat variations. W/H could not evaluate visceral fat loss, because of simultaneous decreases in waist and hip circumferences. Ultrasound was able to measure small reductions in intra-abdominal fat.

[Value of echography in the measurement of changes in the total and visceral adipose mass]. / Validità dell'ecografia nella valutazione delle modificazioni della massa adiposa totale e viscerale.

Various methods to assess lean and fat body masses and abdominal-visceral adipose tissue were compared in 26 obese women on extremely hypocaloric diets. The following anthropometric parameters were measured before and after 15 days of extreme calorie restriction: arm circumference (A), waist circumference (W), hip circumference (H) and thigh circumference (T); W/H, W/T, A/H and A/T ratios; subcutaneous biceps , triceps , subscapular, abdominal and thigh folds; echographic thickness of abdominal muscle-aorta; area of visceral (VAT), total (AT) and subcutaneous adipose tissue measured using computed tomography, lean and fat body masses assessed by impedance measurement. Under standard conditions it was shown that echography, like impedance measurement, was the most useful method for assessing lean and fat body masses in obese subjects, whereas plicometry was not found reliable. On extremely hypocaloric diets, echography is able to assess the variations of lean and fat body masses, whereas impedance measurement overestimated the lean body mass. Localisation indexes of visceral fat based on body circumferences were shown not to be suitable for the evaluation of changes in visceral adipose tissue, at least when these were slight. Echography was also the most useful method to assess slight changes in visceral adipose tissue.