Genetic and environmental components of phenotypic variation in immune response and body size of a colonial bird, Delichon urbica (the house martin).

Directional selection for parasite resistance is often intense in highly social host species. Using a partial cross-fostering experiment we studied environmental and genetic variation in immune response and morphology in a highly colonial bird species, the house martin (Delichon urbica). We manipulated intensity of infestation of house martin nests by the haematophagous parasitic house martin bug Oeciacus hirundinis either by spraying nests with a weak pesticide or by inoculating them with 50 bugs. Parasitism significantly affected tarsus length, T cell response, immunoglobulin and leucocyte concentrations. We found evidence of strong environmental effects on nestling body mass, body condition, wing length and tarsus length, and evidence of significant additive genetic variance for wing length and haematocrit. We found significant environmental variance, but no significant additive genetic variance in immune response parameters such as T cell response to the antigenic phytohemagglutinin, immunoglobulins, and relative and absolute numbers of leucocytes. Environmental variances were generally greater than additive genetic variances, and the low heritabilities of phenotypic traits were mainly a consequence of large environmental variances and small additive genetic variances. Hence, highly social bird species such as the house martin, which are subject to intense selection by parasites, have a limited scope for immediate microevolutionary response to selection because of low heritabilities, but also a limited scope for long-term response to selection because evolvability as indicated by small additive genetic coefficients of variation is weak.

Differences in whole-body fat oxidation kinetics between cycling and running.

This study aimed to quantitatively describe and compare whole-body fat oxidation kinetics in cycling and running using a sinusoidal mathematical model (SIN). Thirteen moderately trained individuals (7 men and 6 women) performed two graded exercise tests, with 3-min stages and 1 km h(-1) (or 20 W) increment, on a treadmill and on a cycle ergometer. Fat oxidation rates were determined using indirect calorimetry and plotted as a function of exercise intensity. The SIN model, which includes three independent variables (dilatation, symmetry and translation) that account for main quantitative characteristics of kinetics, provided a mathematical description of fat oxidation kinetics and allowed for determination of the intensity (Fat(max)) that elicits maximal fat oxidation (MFO). While the mean fat oxidation kinetics in cycling formed a symmetric parabolic curve, the mean kinetics during running was characterized by a greater dilatation (i.e., widening of the curve, P < 0.001) and a rightward asymmetry (i.e., shift of the peak of the curve to higher intensities, P = 0.01). Fat(max) was significantly higher in running compared with cycling (P < 0.001), whereas MFO was not significantly different between modes of exercise (P = 0.36). This study showed that the whole-body fat oxidation kinetics during running was characterized by a greater dilatation and a rightward asymmetry compared with cycling. The greater dilatation may be mainly related to the larger muscle mass involved in running while the rightward asymmetry may be induced by the specific type of muscle contraction.

Thyroid function and prevalent and incident metabolic syndrome in older adults: the Health, Ageing and Body Composition Study.

OBJECTIVE: Both subclinical hypothyroidism and the metabolic syndrome have been associated with increased risk of coronary heart disease events. It is unknown whether the prevalence and incidence of metabolic syndrome is higher as TSH levels increase, or in individuals with subclinical hypothyroidism. We sought to determine the association between thyroid function and the prevalence and incidence of the metabolic syndrome in a cohort of older adults. DESIGN: Data were analysed from the Health, Ageing and Body Composition Study, a prospective cohort of 3075 community-dwelling US adults. PARTICIPANTS: Two thousand one hundred and nineteen participants with measured TSH and data on metabolic syndrome components were included in the analysis. MEASUREMENTS: TSH was measured by immunoassay. Metabolic syndrome was defined per revised ATP III criteria. RESULTS: At baseline, 684 participants met criteria for metabolic syndrome. At 6-year follow-up, incident metabolic syndrome developed in 239 individuals. In fully adjusted models, each unit increase in TSH was associated with a 3% increase in the odds of prevalent metabolic syndrome (OR, 1.03; 95% CI, 1.01-1.06; P = 0.02), and the association was stronger for TSH within the normal range (OR, 1.16; 95% CI, 1.03-1.30; P = 0.02). Subclinical hypothyroidism with a TSH > 10 mIU/l was significantly associated with increased odds of prevalent metabolic syndrome (OR, 2.3; 95% CI, 1.0-5.0; P = 0.04); the odds of incident MetS was similar (OR 2.2), but the confidence interval was wide (0.6-7.5). CONCLUSIONS: Higher TSH levels and subclinical hypothyroidism with a TSH > 10 mIU/l are associated with increased odds of prevalent but not incident metabolic syndrome.

Mortality risk of obesity and underweight is overestimated with self-reported body mass index.

Obese persons (those with a body mass index [BMI] ≥30 kg/m2) tend to underestimate their weight, leading to an underestimation of their true (measured) BMI and obesity prevalence.1,2 In contrast, underweight people (BMI <18.5 kg/m2) tend to report themselves heavier, resulting in a higher BMI compared with measured BMI and an underestimation of underweight prevalence.

Reproducibility and within-day variability of body fat measurements using segmental bipolar bioelectrical impedance in women

BACKGROUND AND AIMS: little is known regarding the reproducibility of body fat measuring devices; hence, we assessed the between and within-device reproducibility, and the within-day variability of body fat measurements. METHODS: body fat percentage was measured twice on seventeen female students aged between 18 and 20 with a body mass index of 21.9 ± 2.5 kg/m2 (mean ± SD) using seven bipolar bioelectrical impedance devices. Each participant was also measured each hour between 7:00 and 22:00. RESULTS: the correlation between first and second measurements was very high (Spearman r between 0.985 and 1.000, p<0.001), as well as between devices (Spearman r between 0.916 and 0.991, p<0.001). Repeated measurements analysis showed no differences were between devices (p=0.59) or readings (first vs. second: p=0.74). Conversely, significant differences were found between assessment periods throughout the day, measurements made in the morning being lower than those made in the afternoon (F test for repeated values= 6.58, p<0.001). CONCLUSIONS: the between and within-device reproducibility for measuring body fat is high, enabling the use of multiple devices in a single study. Conversely, small but significant changes in body fat measurements occur during the day, urging body fat measurements to be performed at fixed times.

Twenty-four-hour energy expenditure in pregnant and nonpregnant Gambian women, measured in a whole-body indirect calorimeter.

Twenty-four-hour energy expenditure (EE), daily and sleeping EE, and the energy cost of a standardized treadmill exercise were assessed in a respiration chamber in 41 young pregnant Gambian women at 12 (n = 11), 24 (n = 15), and 36 (n = 15) wk of gestation and compared with 13 nonpregnant nonlactating (NPNL) control women. The rate of 24-h EE was significantly higher (P less than 0.001) at 36 wk gestation (8443 +/- 243 kJ/d) than in the NPNL group (6971 +/- 172 kJ/d) or at 12 and 24 wk (7088 +/- 222 and 7188 +/- 192 kJ/d, respectively). Per unit body weight, no more differences in 24-h EE, daily and sleeping EE, or energy cost of walking were observed between pregnant and NPNL women. There was no statistical difference in the 24-h respiratory quotient among the groups. We conclude that the state of pregnancy in Gambian women induces a progressive rise in 24-h EE, which becomes significant in the third trimester and is proportional to body weight.

Melanism, body condition and elevational distribution in the asp viper

Alternative morphotypes can confer important selective advantages in different habitats, whereas they can be penalized in other circumstances. In ectotherms, such as reptiles, the body colour can have direct effects on numerous aspects of their existence, such as thermoregulation or prey-predator interactions. Darker melanic individuals show lower skin reflectance and consequently heat up more rapidly and maintain optimal body temperatures more easily than lighter coloured individuals. As a consequence, melanistic individuals of diurnal species in cool areas may exhibit higher body condition, growth rate, survival and fecundity than lighter coloured individuals. Such advantages of dark coloration may be counterbalanced by a lower crypsis to predators and a decreased foraging efficiency. We investigated, in two montane populations of asp vipers Vipera aspis, the relationship between (1) colour polymorphism and body condition and length and (2) the coloration of individuals and their elevational distribution. We showed significant relationships between (1) the coloration, body condition and sex of individuals; (2) sexes and reproductive state and morph frequency; and (3) colour morphs that were distributed following an elevational gradient. Hence, colour polymorphism plays an important role in the ecology and evolution of the asp viper and is maintained through differential selective pressures.

Sex-specific selective pressures on body mass in the greater white-toothed shrew, Crocidura russula.

The direction, intensity and shape of viability-, sexual- and fecundity selection on body mass were investigated in a natural population of the greater white-toothed shrew (Crocidura russula), combining parentage assignment through molecular techniques and mark-recapture data over several generations. A highly significant stabilizing viability selection was found in both sexes, presumably stemming from the constraints imposed by their insectivorous habits and high metabolic costs. Sexual selection, directional in both sexes, was twice as large in males than in females. Our results suggest that body mass matters in this context by facilitating the acquisition and defense of a breeding territory. No fecundity selection could be detected. The direction of sexual size dimorphism (SSD) was in agreement with the observed pattern of selective pressures: males were heavier than females, because of stronger sexual selection. SSD intensity, however, was low compared with other mammals, because of the low level of polygyny, the active role of females in territory defense and the intensity of stabilizing viability selection.

Is lean body mass decreased after obesity treatment by adjustable gastric banding?

BACKGROUND: There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size. METHODS: Body composition was assessed by dual-energy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7+/-8.4 years, BMI 36.4+/-5.9 kg/m2, mean+/-SD), and in 117 control women (age 44.5+/-7.5 years; BMI 36.7+/-5.5 kg/m2) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM). RESULTS: 1 year after LAGB, body weight loss (-23.7+/-11.6 kg, P<10(-6)) was mainly due to decreased fat mass (-21.2+/-11.2 kg, P<10(-6)), and total LBM was modestly, although significantly, decreased (-2.1+/-4.2 kg, P=0.01). Appendicular LBM (-0.7+/-2.7 kg) and total SMM (-0.9+/-3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM. CONCLUSIONS: Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.

Body dissatisfaction on top of depressive mood among adolescents with severe dysmenorrhea.

OBJECTIVES: This study aims to determine whether adolescent girls with severe dysmenorrhea (SD) have different psychological characteristics from their peers. STUDY DESIGN: Cross-sectional survey (SMASH 02). SETTINGS: Nationally representative sample of adolescents attending post-mandatory education. PARTICIPANTS: N = 7548, of whom 3340 were females, aged 16-20 years. INTERVENTION: Self-administered, anonymous survey consisted of 565 items on 4 main topics: sociodemographic determinants of health, health status, health behaviors, and health care use. OUTCOMES: Body image variables, mental health, and associated variables like sexual abuse and health perceptions. Bivariate analysis and binomial logistic regression controlling for explanatory variables were performed. RESULTS: 12.4% (95% confidence interval [CI]: 11.0-14) declared SD. Compared to their peers, subjects with SD were more likely to report depressive symptoms (adjusted odds ratio [AOR]: 1.73; 95% CI: 1.38-2.15), have a higher gynecological age (AOR: 1.13; 95% CI: 1.05-1.20), and attend vocational school (AOR: 1.33; 95% CI: 1.00-1.76). Moreover, the proportion of those reporting dissatisfaction with their body appearance was higher (AOR: 1.50; 95% CI: 1.02-2.22). CONCLUSION: Patients with SD not only show a different profile from their peers in terms of their mental health academic track and gynecological age, but they are also more dissatisfied with their body appearance. Clinicians should pay particular attention to patients with SD and offer them a global evaluation, bearing in mind what factors can be associated with SD.

Body temperature regulation and outcome after cardiac arrest and therapeutic hypothermia.

OBJECTIVE: Therapeutic temperature modulation is recommended after cardiac arrest (CA). However, body temperature (BT) regulation has not been extensively studied in this setting. We investigated BT variation in CA patients treated with therapeutic hypothermia (TH) and analyzed its impact on outcome. METHODS: A prospective cohort of comatose CA patients treated with TH (32-34°C, 24h) at the medical/surgical intensive care unit of the Lausanne University Hospital was studied. Spontaneous BT was recorded on hospital admission. The following variables were measured during and after TH: time to target temperature (TTT=time from hospital admission to induced BT target <34°C), cooling rate (spontaneous BT-induced BT target/TTT) and time of passive rewarming to normothermia. Associations of spontaneous and induced BT with in-hospital mortality were examined. RESULTS: A total of 177 patients (median age 61 years; median time to ROSC 25 min) were studied. Non-survivors (N=90, 51%) had lower spontaneous admission BT than survivors (median 34.5 [interquartile range 33.7-35.9]°C vs. 35.1 [34.4-35.8]°C, p=0.04). Accordingly, time to target temperature was shorter among non-survivors (200 [25-363]min vs. 270 [158-375]min, p=0.03); however, when adjusting for admission BT, cooling rates were comparable between the two outcome groups (0.4 [0.2-0.5]°C/h vs. 0.3 [0.2-0.4]°C/h, p=0.65). Longer duration of passive rewarming (600 [464-744]min vs. 479 [360-600]min, p<0.001) was associated with mortality. CONCLUSIONS: Lower spontaneous admission BT and longer time of passive rewarming were associated with in-hospital mortality after CA and TH. Impaired thermoregulation may be an important physiologic determinant of post-resuscitation disease and CA prognosis. When assessing the benefit of early cooling on outcome, future trials should adjust for patient admission temperature and use the cooling rate rather than the time to target temperature.