Lipid reserves,fasting capability and the evolution of nestling obesity in procellariiform seabirds

Several alternative explanations have been proposed to account for the evolution of nestling obesity in a variety of avian groups. These predict quite different patterns of fat accumulation, storage and use by chicks of different ages. Yet surprisingly few studies have measured changes in body composition during chick development. We tested the applicability of these hypotheses for fulmars, Fulmarus glacialis, by direct measurement of changes in water, lipid and lean dry mass in growing chicks. Lipid and lean dry mass increased until ca. 70% of the way through chick rearing, but then levelled off. Total body water also increased until the same stage, but gradually declined thereafter, and it was this change rather than fat metabolism that resulted in mass recession. The observed pattern of a continued increase in stored lipid, and most importantly, its maintenance all the way through the mass-recession phase until chicks reach fledging, is incompatible with many of the proposed hypotheses. We suggest that the most likely ultimate explanation for large fat deposits is to fuel chicks during the initial critical period away from the nest site while they learn to forage     

Developmental changes in response to subatmospheric pressure loading of the upper airway.

Children snore less than adults and have fewer obstructive apneas, suggesting a less collapsible upper airway. We therefore hypothesized that the compensatory upper airway responses to subatmospheric pressure loading decrease with age because of changes in upper airway structure and ventilatory drive. We measured upper airway upstream pressure-flow relationships during sleep in 20 nonsnoring, nonobese children and adults. Measurements were made by correlating maximal inspiratory airflow with the level of nasal pressure applied via a mask. The slope of the upstream pressure-flow curve (S(PF)) was used to characterize upper airway function. We found that S(PF) was flatter in children than in adults (8 +/- 5 vs. 30 +/- 18 ml x s(-1). cmH(2)O(-1), P < 0.002) and that S(PF) correlated with age (r = 0.62, P < 0.01) and body mass index (r = 0. 63, P < 0.01). The occlusion pressure in 100 ms during sleep was measured in six children and two adults; it correlated inversely with S(PF) (r = -0.80, P < 0.02). We conclude that the upper airway compensatory responses to subatmospheric pressure loading decrease with age. This is associated with increased body mass index, even in nonsnoring, nonobese subjects. Ventilatory drive during sleep plays a role in modulating upper airway responses.     

Differences in Body Fat Distribution Play a Role in the Lower Levels of Elevated Fasting Glucose amongst Ghanaian Migrant Women Compared to Men

Background

Despite higher levels of obesity, West African migrant women appear to have lower rates of type 2 diabetes than their male counterparts. We investigated the role of body fat distribution in these differences.

Methods

Cross-sectional study of Ghanaian migrants (97 men, 115 women) aged 18–60 years in Amsterdam, the Netherlands. Weight, height, waist and hip circumferences were measured. Logistic regression was used to explore the association of BMI, waist and hip measurements with elevated fasting glucose (glucose≥5.6 mmol/L). Linear regression was used to study the association of the same parameters with fasting glucose.

Results

Mean BMI, waist and hip circumferences were higher in women than men while the prevalence of elevated fasting glucose was higher in men than in women, 33% versus 19%. With adjustment for age only, men were non-significantly more likely than women to have an elevated fasting glucose, odds ratio (OR) 1.81, 95% CI: 0.95, 3.46. With correction for BMI, the higher odds among men increased and were statistically significant (OR 2.84, 95% CI: 1.32, 6.10), but with consideration of body fat distribution (by adding both hip and waist in the analysis) differences were no longer significant (OR 1.56 95% CI: 0.66, 3.68). Analysis with fasting glucose as continuous outcome measure showed somewhat similar results.

Conclusion

Compared to men, the lower rates of elevated fasting glucose observed among Ghanaian women may be partly due to a more favorable body fat distribution, characterized by both hip and waist measurements.     

Structure characterization of the central repetitive domain of high molecular weight gluten proteins. II. Characterization in solution and in the dry state.

The structure of the central repetitive domain of high molecular weight HMW) wheat gluten proteins was characterized in solution and in the dry state using HMW proteins Bx6 and Bx7 and a subcloned, bacterially expressed part of the repetitive domain of HMW Dx5. Model studies of the HMW consensus peptides PGQGQQ and GYYPTSPQQ formed the basis for the data analysis (van Dijk AA et al., 1997, Protein Sci 6:637-648). In solution, the repetitive domain contained a continuous nonoverlapping series of both type I and type II II beta-turns at positions predicted from the model studies; type II beta-turns occurred at QPGQ and QQGY sequences and type I beta-turns at YPTS and SPQQ. The subcloned part of the HMW Dx5 repetitive domain sometimes migrated as two bands on SDS-PAGE; we present evidence that this may be caused by a single amino acid insertion that disturbs the regular structure of beta-turns. The type I beta-turns are lost when the protein is dried on a solid surface, probably by conversion to type II beta-turns. The homogeneous type II beta-turn distribution is compatible with the formation of a beta-spiral structure, which provides the protein with elastic properties. The beta-turns and thus the beta-spiral are stabilized by hydrogen bonds within and between turns. Reformation of this hydrogen bonding network after, e.g., mechanical disruption may be important for the elastic properties of gluten proteins.     

Impacts of logging and conversion of rainforest to oil palm on the functional diversity of birds in Sundaland

Commercial selective logging and the conversion of primary and degraded forests to agriculture are the biggest threats to tropical biodiversity. Our understanding of the impacts of these disturbances and the resulting local extinctions on the functional roles performed by the remaining species is limited. We address this issue by examining functional diversity (FD), which quantifies a range of traits that affect a species' ecological role in a community as a single continuous metric. We calculated FD for birds across a gradient of disturbance from primary forest through intensively logged forest to oil palm plantations on previously forested land in Borneo, Southeast Asia, a hotspot of imperilled biodiversity. Logged rainforest retained similar levels of FD to unlogged rainforest, even after two logging rotations, but the conversion of logged forest to oil palm resulted in dramatic reductions in FD. The few remaining species in oil palm filled a disproportionately wide range of functional roles but showed very little clustering in terms of functional traits, suggesting that any further extinctions from oil palm would reduce FD even further. Determining the extent to which the changes we recorded were due to under‐utilization of resources within oil palm or a reduction in the resources present is an important next step. Nonetheless our study improves our understanding of the stability and resilience of functional diversity in these ecosystems and of the implications of land‐use changes for ecosystem functioning.     

Intensive Lifestyle Intervention in General Practice to Prevent Type 2 Diabetes among 18 to 60-Year-Old South Asians: 1-Year Effects on the Weight Status and Metabolic Profile of Participants in a Randomized Controlled Trial

Aim

To study 1-year effectiveness of an intensive, culturally targeted lifestyle intervention in general practice for weight status and metabolic profile of South-Asians at risk of type 2 diabetes.

Methods

536 South-Asians at risk of type 2 diabetes were randomized to an intervention (n = 283) or control (n = 253) group. The intervention, which was targeted culturally to the South-Asian population, consisted of individual lifestyle counselling, a family session, cooking classes, and supervised physical activity programme. All components of the intervention were carried out by professionals as part of their daily clinical practice. The control group received generic lifestyle advice. Change in weight status and metabolic profile were assessed after 1 year.

Results

After 1 year, 201 participants were lost to follow-up. Remaining participants in intervention (n = 177) and control (n = 158) group had similar baseline characteristics. Weight loss in the intervention group was 0.2±3.3 kg, weight gain in the control group was 0.4±3.1 kg (p = 0.08). Changes in other weight-related measurements did not differ significantly between groups. Furthermore, there were no differences between groups in changes of metabolic profile. All results remained similar after repeating analyses in a multiple imputed dataset.

Discussion

An intensive, culturally targeted, lifestyle intervention of 1 year did not improve weight status and metabolic profile of South-Asians at risk of type 2 diabetes. The laborious recruitment, high drop-out, and lack of effectiveness emphasise the difficulty of realising health benefits in practice and suggest that this strategy might not be the optimal approach for this population.

Trial Registration

Nederlands Trial Register NTR1499     

The effect on mental health of a large scale psychosocial intervention for survivors of mass violence: a quasi-experimental study in Rwanda

Background

War has serious and prolonged mental health consequences. It is argued that post-emergency mental health interventions should not only focus on psychological factors but also address the social environment. No controlled trials of such interventions exist. We studied the effect on mental health of a large scale psychosocial intervention primarily aimed at social bonding in post-genocide Rwanda. The programme is implemented at population level without diagnostic criteria for participation. It is open to any person older than 15 years, and enables participation of over 1500 individuals per year. We postulated that the mental health of programme participants would improve significantly relative to non-participants.

Methods and Findings

We used a prospective quasi-experimental study design with measurement points pre and post intervention and at 8 months follow-up. 100 adults from both sexes in the experimental condition entered the study; follow-up measurements were taken from 81. We selected a control group of 100 respondents with similar age, sex and symptom score distribution from a random community sample in the same region; of these, 73 completed the study. Mental health was assessed by use of the Self Reporting Questionnaire (SRQ-20), a twenty item instrument to detect common mental disorders in primary health care settings. Mean SRQ-20 scores decreased by 2.3 points in the experimental group and 0.8 in the control group (p = 0.033). Women in the experimental group scoring above cut-off at baseline improved with 4.8 points to below cut-off (p<0.001). Men scoring above cut-off at baseline showed a similar trend which was statistically non-significant. No adverse events were observed.

Conclusions

A large scale psychosocial intervention primarily aimed at social bonding caused a lasting improvement of mental health in survivors of mass violence in Rwanda. This approach may have a similar positive effect in other post-conflict settings.

Trial Registration

Nederlands Trial Register 1120