Neonatal anthropometrics and body composition in obese children investigated by dual energy X-ray absorptiometry

Epidemiological and animal studies have suggested an effect of the intrauterine milieu upon the development of childhood obesity. This study investigates the relationship between body composition measured by dual energy X-ray absorptiometry expressed as body fat percent, body fat mass index (BFMI), and fat free mass index (FFMI) in obese children and the preceding in utero conditions expressed by birth weight, birth length, and birth weight for gestational age. The study cohort consisted of 776 obese Danish children (median age 11.6 years, range 3.6–17.9) with a mean Body Mass Index Standard Deviation Score (BMI SDS) of 2.86 (range 1.64–5.48) treated in our national referral centre. In a linear general regression model adjusted for age, gender, socioeconomic status, and duration of breastfeeding, we found the body fat percent, FFMI, and BFMI at the time of enrolment in childhood obesity treatment to be significantly correlated with both birth weight and birth weight for gestational age. Conclusion: These results indicate a prenatal influence upon childhood obesity. Although there are currently no sufficient data to suggest any recommendations to pregnant women, it is possible that the prenatal period may be considered as a potential window of opportunity for prevention of childhood overweight and obesity.     

Global nutrient transport in a world of giants

The past was a world of giants, with abundant whales in the sea and large animals roaming the land. However, that world came to an end following massive late-Quaternary megafauna extinctions on land and widespread population reductions in great whale populations over the past few centuries. These losses are likely to have had important consequences for broad-scale nutrient cycling, because recent literature suggests that large animals disproportionately drive nutrient movement. We estimate that the capacity of animals to move nutrients away from concentration patches has decreased to about 8% of the preextinction value on land and about 5% of historic values in oceans. For phosphorus (P), a key nutrient, upward movement in the ocean by marine mammals is about 23% of its former capacity (previously about 340 million kg of P per year). Movements by seabirds and anadromous fish provide important transfer of nutrients from the sea to land, totalling ∼150 million kg of P per year globally in the past, a transfer that has declined to less than 4% of this value as a result of the decimation of seabird colonies and anadromous fish populations. We propose that in the past, marine mammals, seabirds, anadromous fish, and terrestrial animals likely formed an interlinked system recycling nutrients from the ocean depths to the continental interiors, with marine mammals moving nutrients from the deep sea to surface waters, seabirds and anadromous fish moving nutrients from the ocean to land, and large animals moving nutrients away from hotspots into the continental interior.

There were giants in the world in those days.Genesis 6:4, King James version

The past was a world of giants, with abundant whales in the oceans and terrestrial ecosystems teeming with large animals. However, most ecosystems lost their large animals, with around 150 mammal megafaunal (here, defined as ≥44 kg of body mass) species going extinct in the late Pleistocene and early Holocene (1, 2). These extinctions and range declines continued up through historical times and, in many cases, into the present (3). No global extinctions are known for any marine whales, but whale densities might have declined between 66% and 99% (4–6). Some of the largest species have experienced severe declines; for example, in the Southern Hemisphere, blue whales (Balaenoptera musculus) have been reduced to 1% of their historical numbers as a result of commercial whaling (4). Much effort has been devoted to determining the cause of the extinctions and declines, with less effort focusing on the ecological impacts of the extinctions. Here, we focus on the ecological impacts, with a specific focus on how nutrient dynamics may have changed on land following the late-Quaternary megafauna extinctions, and in the sea and air following historical hunting pressures.Most biogeochemists studying nutrient cycling focus on in situ production, such as weathering or biological nitrogen (N) fixation, largely ignoring lateral fluxes by animals because they are considered of secondary importance (3). The traditional understanding of biogeochemistry is that “rock-derived” nutrients originate with the weathering of primary rock. These nutrients are then lost to the hydrosphere by leaching or runoff or to the atmosphere by dust, fire, or volatilization. These nutrients slowly make their way to the oceans, where they are buried at the bottom of the sea. Eventually, these sediments are subducted, transformed to metamorphic or igneous rock, and uplifted to be weathered once again. We are left with an impression that nutrient cycling in adjacent landscapes or gyres is disconnected except through the atmosphere or hydrosphere, and that animals play only a passive role as consumers of nutrients. However, this notion may be a peculiar world view that comes from living in an age where the number and size of animals have been drastically reduced from their former bounty. We must wonder: What role do animals play in transporting nutrients laterally across ecosystems on land, vertically through the ocean, or across the ocean land divide?Animal digestion accelerates cycling of nutrients from more recalcitrant forms in decomposing plant matter to more labile forms in excreta after (wild or domestic) herbivore consumption on land (7). For instance, nutrients can be locked in slowly decomposing plant matter until they are liberated for use through animal consumption, digestion, and defecation. This process has been theorized to have played a large role in the Pleistocene steppes of Siberia. Abundant large herbivores ate plants that were rapidly decomposed in their warm guts, liberating the nutrients to be reused. However, following extinctions of these animals, nutrients were hypothesized to have been locked into plant matter that is decomposing only slowly, making the entire ecosystem more nutrient-poor (8). Similarly, at present times, large herbivores enhance nutrient cycling in the grazing lawns of the Serengeti (9).What role do animals play in the spatial movement of nutrients? This question is especially pertinent because animals are most likely to influence the flow of nutrients that are in short supply. There are now a large number of site-level studies that have demonstrated how animals move nutrients from one site to another or across ecosystem boundaries. For example, moose (Alces americanus) transfer significant amounts of aquatic-derived N to terrestrial systems, which likely increases terrestrial N availability in riparian zones (10). Terrestrial predators (e.g., bears, otters, and eagles) feeding on anadromous fish that move from the ocean to freshwater to spawn can transport ocean-derived nutrients to terrestrial ecosystems, a process that has been verified by isotopic analysis (11). Hippopotamuses (Hippopotamus amphibius) supplement aquatic systems with terrestrial-derived nutrients, which strongly enhance aquatic productivity (12). Seabirds transport nutrients from the sea to their breeding colonies onshore (13, 14). Studies have documented increases of soil phosphorus (P) concentrations on seabird islands compared with non-seabird islands that were much stronger than for soil %N and present in soils for up to thousands of years (14). In some sites, increased soil P more than doubled plant P concentrations, but this concentration varied substantially from site to site (14). Furthermore, seabirds and marine mammals play an important role as nutrient vectors aiding in the redistribution of micronutrients, such as iron (Fe) (15). Despite their vastly decreased numbers, the important role of whales in distributing nutrients is just now coming to light. Whales transport nutrients laterally, in moving between feeding and breeding areas, and vertically, by transporting nutrients from nutrient-rich deep waters to surface waters via fecal plumes and urine (16–18). Studies in the Gulf of Maine show that cetaceans and other marine mammals deliver large amounts of N to the photic zone by feeding at or below the thermocline and then excreting urea and metabolic fecal N near the surface (17).More recently, studies have demonstrated that animals can diffuse significant quantities of nutrients from areas of high nutrient concentration to areas of lower nutrient concentration even without mass flow of feces out of the fertile area. For instance, woolly monkeys (Lagothrix lagotricha) in Amazonia transported more P than arrives from dust inputs across a floodplain concentration gradient, without preferentially defecating in the less fertile area, merely by eating and defecating back and forth across the nutrient concentration gradient (19). If a small single species can transport such significant quantities of P, what is the role of all animals in an ecosystem over long periods of time? Two recent studies compiled size relationship data for terrestrial mammals within a random-walk mathematical framework and found that the distribution of nutrients away from a concentration gradient is size-dependent, with larger animals having disproportionally greater importance to this flow of nutrients than smaller animals (20, 21). For the Amazon basin, it was estimated that the extinction of the megafauna may have led to a >98% reduction in the lateral transfer flux of the limiting nutrient P, with large impacts on ecosystem P concentrations in regions outside of the fertile floodplains (20, 21).If large animals are of disproportionate importance, then the obvious question is: What was this nutrient movement like in the past, in a world of giants, when mean animal size was much greater on land and at sea? Furthermore, what was the role of animals in returning nutrients from sea to land, against the passive diffusion gradients? Seabirds and anadromous fish are two important animal groups for the transport of nutrients from sea to land. Both groups are also facing pressure, and 27% of all seabirds are classified as threatened (critically endangered, endangered, or vulnerable), and the largest of all seabirds, the albatross, is the most endangered, with up to 75% of albatross species considered threatened or endangered (22–24)]. Likewise, populations of anadromous fish have declined to less than 10% of their historical numbers in the Pacific Northwest (25) and both the northeastern and northwestern Atlantic (26, 27). There have been many individual site-level studies showing the importance of animals in distributing nutrients, but as far as we are aware, no previous study has attempted to estimate at a global scale how this distribution has changed from the time before human-caused extinctions and exploitation up to today in the oceans, air, rivers, and land. In this study, we aim to estimate three things: (i) the lateral nutrient distribution capacity of terrestrial and marine megafauna, (ii) the global vertical flux of nutrients to surface waters by marine megafauna, and (iii) the global flux of nutrients by seabirds and anadromous fish from the sea to land.     

Species restriction of Herpesvirus saimiri and Herpesvirus ateles: human lymphocyte transformation correlates with distinct signaling properties of viral oncoproteins

The potential of Herpesvirus saimiri (HVS) subgroups A, B and C and Herpesvirus ateles (HVA) to transform primary T cells to permanent growth in vitro is restricted by the primate host species and by viral variability represented by distinct viral oncoproteins. We now addressed the relation between the transforming potential of the different viruses and the signaling pathways activated by transiently expressed oncoproteins. Marmoset lymphocytes were transformed by all HVS subgroups as well as HVA, while transformation of human cells was restricted to HVS-C and, unexpectedly, HVA. NF-κB and Src-family kinase (SFK) activity was required for survival of all transformed lymphocytes. Accordingly, NF-κB was induced by oncoproteins of all viruses. In contrast, SFK-related signaling was detectable only for oncoproteins of HVS-C and HVA. Thus, the restricted transformation of human lymphocytes likely correlates with the specific SFK targeting by these oncoproteins. These results will enable further studies into novel SFK effector mechanisms relevant for T-cell proliferation.     

The adaptive challenge of extreme conditions shapes evolutionary diversity of plant assemblages at continental scales

The tropical conservatism hypothesis (TCH) posits that the latitudinal gradient in biological diversity arises because most extant clades of animals and plants originated when tropical environments were more widespread and because the colonization of colder and more seasonal temperate environments is limited by the phylogenetically conserved environmental tolerances of these tropical clades. Recent studies have claimed support of the TCH, indicating that temperate plant diversity stems from a few more recently derived lineages that are nested within tropical clades, with the colonization of the temperate zone being associated with key adaptations to survive colder temperatures and regular freezing. Drought, however, is an additional physiological stress that could shape diversity gradients. Here, we evaluate patterns of evolutionary diversity in plant assemblages spanning the full extent of climatic gradients in North and South America. We find that in both hemispheres, extratropical dry biomes house the lowest evolutionary diversity, while tropical moist forests and many temperate mixed forests harbor the highest. Together, our results support a more nuanced view of the TCH, with environments that are radically different from the ancestral niche of angiosperms having limited, phylogenetically clustered diversity relative to environments that show lower levels of deviation from this niche. Thus, we argue that ongoing expansion of arid environments is likely to entail higher loss of evolutionary diversity not just in the wet tropics but in many extratropical moist regions as well.

Earth’s most studied biodiversity pattern is the latitudinal diversity gradient (LDG): species richness and evolutionary diversity decrease from the warm, moist, aseasonal tropics toward the colder, more seasonal poles (1–5). Many hypotheses have been proposed to explain the LDG (6), but the tropical conservatism hypothesis (TCH) has garnered much attention due to its focus on interacting ecological and evolutionary mechanisms (1, 2, 7–9) (Fig. 1A).Open in a separate windowFig. 1.A conceptual model of the distribution of evolutionary diversity across latitudinal and climatic gradients under two general mechanisms. (A) TCH—the latitudinal gradient is categorized into tropical or extratropical, and species richness is lower in extratropical regions because they comprise recently derived, evolutionarily poor (phylogenetically nested) subsets of lineages that have had less time for diversification relative to tropical lineages (i.e., lower evolutionary diversity in extratropical regions). The TCH is the prevalent mechanism addressed in studies of LDGs (e.g., ref. 2). (B) Extended TCH—the latitudinal gradient is categorized into four climatic domains: tropical moist, tropical dry, extratropical moist, or extratropical dry, and species richness is lower in extratropical moist, seasonally cold regions because they comprise recently derived, evolutionarily poor subsets of lineages relative to tropical assemblages. Within the tropics, species richness is lower in seasonally dry regions because they comprise recently derived, evolutionary poor subsets of lineages relative to tropical moist regions. Furthermore, extratropical dry regions, which exhibit both pronounced drought and cold temperatures, comprise recently derived, evolutionarily poor subsets of lineages relative to the other three climatic domains. Variation in evolutionary diversity differentiates regions with higher (positive values) or lower (negative) phylogenetic diversity than expected given their taxonomic diversity (e.g., species or generic richness). Thus, low values would indicate higher phylogenetic nestedness in these regions.The TCH makes two key assumptions: 1) that most clades of animals and plants have a tropical origin (3, 10, 11) and 2) that after the global cooling initiated at the end of the Eocene (34 Mya), the trait innovations necessary to persist and thrive in temperate regions (e.g., freezing tolerance) (12) are phylogenetically conserved within a small subset of more recently derived lineages (7, 12–14). Hence, the TCH predicts that relative to tropical regions, species richness in the temperate zone will be lower because temperate biodiversity stems from these few, more recently derived lineages that are phylogenetically nested within clades of tropical origin, and thus have had less time for diversification.While the inability of most plant lineages to survive regular freezing conditions clearly contributes to the LDG for flowering plants (2, 12), temperature may not be the sole stressor associated with the LDG. In particular, drought stress from either low precipitation (relative to evapotranspiration) or precipitation seasonality may have also disproportionately shaped diversity gradients (15, 16). Nonetheless, recent studies testing the validity of the TCH have ignored gradients of water availability in full (2) or have not included regions of extreme cold and drought in their analyses (17). Here, we evaluate an extended view of the TCH (8) (Fig. 1B). This view still assumes a tropical origin for most clades of extant species but generalizes the conservatism assumption such that the key innovations needed to thrive in any harsh or seasonal conditions, not just freezing temperatures, are limited to a few lineages.Under assumptions of the extended TCH, we would predict that any seasonally cold or dry environment will be made up of clusters of taxa within a few evolutionarily nested lineages of tropical origin. In these seasonal environments, we thus expect lower evolutionary diversity relative to regions that are aseasonal, warm, and wet year-round (henceforth, “tropical moist”).Although we make no assumptions regarding the age of extratropical dry environments, besides the TCH assumption of tropical moist origin for most clades of extant species (3, 10, 11), under the extended TCH, we would also predict that the number of lineages able to cope with more than one stressor is even more limited. This means that assemblages in extratropical dry regions exhibiting both pronounced drought and cold temperatures will consist of yet smaller subsets of lineages relative to environments that are either tropical moist or seasonal. In these extreme environments, we thus expect the lowest evolutionary diversity of any environment.To test the predictions of the extended TCH, we used a comprehensive dataset on the distribution of flowering plant species (angiosperms) across the Americas (18) and a time-scaled molecular phylogeny (12) for 3,847 angiosperm genera in the dataset. We then quantified species richness, phylogenetic diversity, and evolutionary diversity of plant assemblages a priori classified into one of 12 biomes (Fig. 2A) (19). Each assemblage represented a list of plant species contained within a 100 × 100 km grid cell, and the full extent of North and South America comprised 3,928 of these grid cells (hereafter “assemblages”). The species composition of the assemblages was derived from range maps available in BIEN (Botanical Information and Ecology Network; see Materials and Methods for further details). Evolutionary diversity was measured as the total phylogenetic branch length in an assemblage, standardized for the total number of genera in this assemblage, thus describing patterns of accumulated lineage diversity over evolutionary timescales—a metric we refer to as lineage diversity (LD; sensu ref. 16).Open in a separate windowFig. 2.Patterns of species richness (SR) and LD in angiosperm assemblages across the Americas. (A) Assemblages are classified into distinct biomes [following Olson et al. (19)]. (B) Geographical patterns of variation in SR for 3,928 angiosperm assemblages (sites). Each site is defined as the assemblage of angiosperm genera in a 100 × 100 km grid cell. Warmer colors indicate higher SR (i.e., the darkest red is assigned to the plant assemblage with SR = 8,924 species). Contours represent biome delimitations and are identical to contours in A. Dashed line indicates the Equator. (C) Geographical patterns of variation in LD for 3,928 angiosperm assemblages. LD was calculated as the total phylogenetic branch length in assemblages, standardized for genus-level richness. Warmer colors indicate higher LD (i.e., the darkest red is assigned to the plant assemblage with LD = 2.25 [sesPD]). (D) Distribution of LD values across biomes in the Americas, grouped by their climatic domain. Values represent 1,000 means of LD from 10 assemblages randomly selected within each biome. Colors of violin polygons are identical to A. Biomes are sorted by their median, and the dashed line indicates the highest median (i.e., temperate mixed forests). Values in parentheses after each biome name are the number of assemblages in that biome. Post hoc Dunn tests comparing pairwise biome means are provided in SI Appendix, Table S2. Refer to SI Appendix, Fig. S1 for a colorblind-friendly version of B and C.     

From the Cover: Megafauna and ecosystem function from the Pleistocene to the Anthropocene

Large herbivores and carnivores (the megafauna) have been in a state of decline and extinction since the Late Pleistocene, both on land and more recently in the oceans. Much has been written on the timing and causes of these declines, but only recently has scientific attention focused on the consequences of these declines for ecosystem function. Here, we review progress in our understanding of how megafauna affect ecosystem physical and trophic structure, species composition, biogeochemistry, and climate, drawing on special features of PNAS and Ecography that have been published as a result of an international workshop on this topic held in Oxford in 2014. Insights emerging from this work have consequences for our understanding of changes in biosphere function since the Late Pleistocene and of the functioning of contemporary ecosystems, as well as offering a rationale and framework for scientifically informed restoration of megafaunal function where possible and appropriate.     

The impact of response time reliability on CPR incidence and resuscitation success: a benchmark study from the German Resuscitation Registry

Introduction

Sudden cardiac arrest is one of the most frequent causes of death in the world. In highly qualified emergency medical service (EMS) systems, including well-trained emergency physicians, spontaneous circulation may be restored in up to 53% of patients at least until admission to hospital. Compared with these highly qualified EMS systems, markedly lower success rates are observed in other systems. These data clearly show that there are considerable differences between EMS systems concerning treatment success following cardiac arrest and resuscitation, although in all systems international guidelines for resuscitation are used. In this study, we investigated the impact of response time reliability (RTR) on cardiopulmonary resuscitation (CPR) incidence and resuscitation success by using the return of spontaneous circulation (ROSC) after cardiac arrest (RACA) scores and data from seven German EMS systems participating in the German Resuscitation Registry.

Methods

Anonymised patient data after out-of-hospital cardiac arrest gathered from seven EMS systems in Germany from 2006 to 2009 were analysed with regard to socioeconomic factors (population, area and EMS unit-hours), process quality (RTR, CPR incidence, special CPR measures and prehospital cooling), patient factors (age, gender, cause of cardiac arrest and bystander CPR). End points were defined as ROSC, admission to hospital, 24-hour survival and hospital discharge rate. χ² tests, odds ratios and the Bonferroni correction were used for statistical analyses.

Results

Our present study comprised 2,330 prehospital CPR patients at seven centres. The incidence of sudden cardiac arrest ranged from 36.0 to 65.1/100,000 inhabitants/year. We identified two EMS systems (RTR < 70%) that reached patients within 8 minutes of the call to the dispatch centre 62.0% and 65.6% of the time, respectively. The other five EMS systems (RTR > 70%) reached patients within 8 minutes of the call to the dispatch centre 70.4% up to 95.5% of the time. EMS systems arriving relatively later at the patients side (RTR < 70%) initiate CPR less frequently and admit fewer patients alive to hospital (calculated per 100,000 inhabitants/year) (CPR incidence (1/100,000 inhabitants/year) RTR > 70% = 57.2 vs RTR < 70% = 36.1, OR = 1.586 (99% CI = 1.383 to 1.819); P < 0.01) (admitted to hospital with ROSC (1/100,000 inhabitants/year) RTR > 70% = 24.4 vs RTR < 70% = 15.6, OR = 1.57 (99% CI = 1.274 to 1.935); P < 0.01). Using ROSC rate and the multivariate RACA score to predict outcomes, we found that the two groups did not differ, but ROSC rates were higher than predicted in both groups (ROSC RTR > 70% = 46.6% vs RTR < 70% = 47.3%, OR = 0.971 (95% CI = 0.787 to 1.196); P = n.s.) (ROSC RACA RTR > 70% = 42.4% vs RTR < 70% = 39.5%, OR = 1.127 (95% CI = 0.911 to 1.395); P = n.s.)

Conclusion

This study demonstrates that, on the level of EMS systems, faster ones more often initiate CPR and increase the number of patients admitted to hospital alive. Furthermore, we show that, with very different approaches, all centres that adhere to and are intensely trained according to the 2005 European Resuscitation Council guidelines are superior and, on the basis of international comparisons, achieve excellent success rates following CPR.