Preliminary Evaluation of Sexual Problems in Combat Veterans with PTSD

This study evaluated the potential relationship between posttraumatic stress disorder (PTSD) and sexual problems. The Golombok Rust Inventory of Sexual Satisfaction was mailed to combat veterans currently in treatment at an outpatient PTSD clinic. Completed questionnaires were received from 90 patients. Results indicated that over 80% of subjects were experiencing clinically relevant sexual difficulties. Impotence and premature ejaculation were the most frequently reported problems that have corresponding psychological diagnoses. The rates of sexual problems for this sample of veterans with PTSD was similar to those reported in other studies and exceeded rates of similar problems found in samples from community samples. These data suggest mat PTSD may be a risk factor for sexual problems.     

Inter-laboratory validation of PCR-based detection of Mycobacterium tuberculosis in formalin-fixed, paraffin-embedded tissues

The present study is based on the initiative for quality assurance in pathology of the German Society of Pathology and the Professional Association of German Pathologists. Four panel laboratories with experience and expertise in polymerase chain reaction (PCR) detection of Mycobacterium tuberculosis were selected to establish the prerequisites for continuous external laboratory trials, in particular, by providing pre-tested specimens and evaluation criteria for participating institutes. In the first step, the four panel laboratories performed an internal trial to test their own reliability and reproducibility. Paraffin sections and DNA preparations from 34 tissues (25 clinical specimens and 9 controls) totalling to 66 samples were evaluated by each panel institute according to their own protocols. The methodologies differed and are described in detail. Despite these differences, a high degree of inter-laboratory reliability was achieved. In this report, we summarise our results including the correlation with the histology and provide recommendations for applying PCR-based methodology for the detection of mycobacterial DNA in surgical specimens. Supplementary data are available online at (rubric Forschung). Pre-tested specimens are now available for the external trial and can be ordered from the steering institute via Oligene (). All molecular pathology laboratories are invited to participate in this quality assurance initiative.     

Stepwise development of a clinical expert system in rheumatology

Summary The evaluation of computer expert systems, a promising diagnostic tool for future application in clinical medicine, is of great importance. We present here the evaluation of our expert system, RHEUMA. It is stressed, that repeated retrospective testing and updating of an expert system and its subsequent repeated assessment in clinical use and surroundings is mandatory. This increases the diagnostic accuracy of the system. For our system this is demonstrated under three separate conditions. In the first study the information available for the computer system (mainframe) came from medical histories only. Here an error rate of about 25% — similar to that of physicians themselves using the same information — was observed in 358 outpatients, compared to the final diagnoses of physicians also relying solely on information from medical histories. In a second step a completely new system on a personal computer was developed with all relevant diagnostic information. The error rate of this system (0.4%) was much too optimistic because the knowledge base was changed during the study, affecting about 30% of the 282 prospectively recruited outpatients. In a third step the efficacy of the expert system was tested in an additional hospital without the diagnostic involvement of the first testing clinic. The error rate of the system without changing the knowledge base reached 11% in 51 outpatients in this rheumatology clinic. This result reflects the diagnostic accuracy of the system today. Its ability to specify the same diagnoses which clinical experts reached approached 90%. Considerable time is needed for such prospective testing, with repeated updating of the knowledge base — in our case for both the two systems and field studies of 2 years each. Further prospective field testing with physicians not specialized in rheumatology and with a larger number of patients is necessary before the system can be used in clinical routine.Dedicated to Prof. Dr. N. Zöllner on the occasion of his 70th birthday     

The Impact of Familial Predisposition to Obesity and Cardiovascular Disease on Childhood Obesity

The prevalence of childhood obesity has reached alarming rates world-wide. The aetiology seems to be an interplay between genetic and environmental factors, and a surrogate measure of this complex interaction is suggested as familial predisposition. Familial predisposition to obesity and related cardiovascular disease (CVD) complications constitute the presence of obesity and/or obesity-related complications in primarily blood-related family members. The approaches of its measurement and applicability vary, and the evidence especially of its influence on obesity and obesity treatment in childhood is limited. Studies have linked a familial predisposition of obesity, CVD (hypertension, dyslipidaemia and thromboembolic events), and type 2 diabetes mellitus to BMI as well as other adiposity measures in children, suggesting degrees of familial aggregation of metabolic derangements. A pattern of predispositions arising from mothers, parents or grandparents as being most influential have been found, but further comprehensive studies are needed in order to specify the exact implications of familial predisposition. In the scope of childhood obesity this article reviews the current literature regarding familial predisposition to obesity and obesity-related complications, and how these familial predispositions may impact obesity in the offspring.Key Words: Pediatric obesity, Familial predisposition, Cardiovascular diseases, Diabetes mellitus type 2     

Functional trait space and the latitudinal diversity gradient

The processes causing the latitudinal gradient in species richness remain elusive. Ecological theories for the origin of biodiversity gradients, such as competitive exclusion, neutral dynamics, and environmental filtering, make predictions for how functional diversity should vary at the alpha (within local assemblages), beta (among assemblages), and gamma (regional pool) scales. We test these predictions by quantifying hypervolumes constructed from functional traits representing major axes of plant strategy variation (specific leaf area, plant height, and seed mass) in tree assemblages spanning the temperate and tropical New World. Alpha-scale trait volume decreases with absolute latitude and is often lower than sampling expectation, consistent with environmental filtering theory. Beta-scale overlap decays with geographic distance fastest in the temperate zone, again consistent with environmental filtering theory. In contrast, gamma-scale trait space shows a hump-shaped relationship with absolute latitude, consistent with no theory. Furthermore, the overall temperate trait hypervolume was larger than the overall tropical hypervolume, indicating that the temperate zone permits a wider range of trait combinations or that niche packing is stronger in the tropical zone. Although there are limitations in the data, our analyses suggest that multiple processes have shaped trait diversity in trees, reflecting no consistent support for any one theory.Species richness increases toward the equator (1, 2) in major clades of both extant and extinct species of plants and animals (3, 4). The generality of the pattern hints at a correspondingly general explanation, yet the latitudinal gradient in species richness remains one of ecology’s greatest unsolved puzzles. Long-running debates over the causes of the latitudinal gradient of species richness have focused on ecological, evolutionary, and geographic explanations (5–10). Although there has been some progress (11), it is also increasingly clear that there are numerous obstacles to understanding the primary drivers of the latitudinal gradient, including an ever-increasing number of hypotheses (12, 13), challenges in clearly separating their interdependencies (14, 15), and difficulties in rigorously falsifying their assumptions and predictions (16).More powerful tests of biodiversity theories need to move beyond species richness and instead explicitly focus on the mechanisms generating the gradient, by recasting the theories in terms of other measures of diversity, such as functional diversity (17–19). For example, explanations that assume species richness is limited by resource availability have often focused on the strength of species interactions, life history differences, and environmental constraints on how species pack into niche space (20). Evolutionary hypotheses have focused on differences in diversification rates, as well as the influence of species interactions on diversification rates (9). These interaction-based explanations implicitly refer to the degree of ecological differentiation among species, and therefore to trait dispersion within clades and assemblages, suggesting that patterns of functional diversity may provide a more powerful test of theory than taxonomic richness (21).A particularly important concept that unifies many ecological and evolutionary theories is the concept of the Hutchinsonian multidimensional niche (22). Hutchinsonian niches can be quantified by assessing the functional trait hypervolumes that characterize phenotypic space occupied by a set of species. Quantifying the volume, overlap, and packing of functional trait space at different spatial scales enables inferences about how differing ecological and evolutionary processes structure functional diversity and ecological strategies (23, 24).Here, we recast several contrasting hypotheses for the latitudinal gradient in terms of functional trait space. We focus on the proximate ecological mechanisms that ultimately can influence evolutionary processes. We quantify tree functional trait space across latitude at three spatial scales: (i) within assemblages (alpha), (ii) among assemblages (beta), and (iii) among biomes (gamma). For alpha and beta analyses, we use tree species assemblage data from 620 standardized 0.1-ha forest plots (Fig. 1A); for gamma analyses, we calculated the latitudinal range distributions for 520 New World tree species where we had sufficient data on geographic distribution and functional traits. In total, across all analyses, we used paired geographic occurrence data with trait data for 6,839 tree species.Open in a separate windowFig. 1.(A) Spatial distribution of the 620 0.1-ha forest plots used in this study. Plots are colored by richness. Plots cover most of the New World forested climate space (Fig. S1). (B) Relationship between absolute latitude and alpha hypervolume for tropical (red triangles) and temperate (blue pluses) plots. (C) Alpha hypervolume as a function of effective species richness (number of species with full trait coverage). We compare this hypervolume with a null expectation based on sampling the same number of species from the regional pool (median, dark gray line; 90% quantile range, light gray envelope).We primarily measured hypervolumes for three central traits hypothesized to characterize major axes of ecological strategy variation (25): specific leaf area (SLA), maximum height, and seed mass. SLA represents the tradeoff between leaf longevity and maximum photosynthetic rate (26); height is important for light competition and dispersal (27); and seed mass represents tradeoffs between fecundity, dispersal, and seedling survival (27). Although whole-plant resource strategies can be more fully assessed in higher dimensions (28, 29), we focus on these traits because of data availability (Materials and Methods). We use a hypervolume algorithm for calculating the volume and overlap of trait space (30) (Materials and Methods). All hypervolumes are reported in units of SDs of centered and scaled log-transformed trait values, raised to the power of the number of trait dimensions used.At all scales, our overall results and conclusions are similar (i) with and without gap-filling missing data, (ii) if we use convex hulls instead of hypervolumes to calculate trait spaces, and (iii) if we include additional trait axes. Additional details are given in Figs. S2–S7.     

Influence of peritoneal dialysis solution on measurements of fluid status by bioimpedance spectroscopy

Purpose and methods

The accurate estimation of volume status is a central problem in dialysis patients. Recently, a bioimpedance spectroscopy (BIS) device (BCM Body Composition Monitor FMC, Germany) has attained growing interest in this regard. By processing the raw data for extracellular water (ECW) and intracellular water (ICW) by means of a validated body composition model, this device allows a quantification of the individual fluid overload (FO) compared to a representative healthy population. In this study, we addressed the issue whether the presence of peritoneal dialysate has an impact on measurements of FO by BIS in PD patients.

Results

Forty-two BIS measurements using the BCM device were performed both in the absence (D?) and presence (D+) of peritoneal dialysate in 17 stable PD patients. Data for ECW, ICW and FO (D+; D?) were analyzed by paired t test and linear regression. Mean FO was 0.99 ± 1.17 L in D? and 0.94 ± 1.27 in D+ (p = n.s. paired t test). Linear regression demonstrated an excellent degree of conformity between FO (D?) and FO (D+) (r ² = 0.93).

Conclusion

The presence of peritoneal fluid in PD patients has a negligible influence on measurements of FO by BIS. The BIS measurements can be therefore conveniently and reliably done without emptying the peritoneal cavity; this may facilitate the use of BIS in this particular group of patients.     

Global water resources affected by human interventions and climate change

Humans directly change the dynamics of the water cycle through dams constructed for water storage, and through water withdrawals for industrial, agricultural, or domestic purposes. Climate change is expected to additionally affect water supply and demand. Here, analyses of climate change and direct human impacts on the terrestrial water cycle are presented and compared using a multimodel approach. Seven global hydrological models have been forced with multiple climate projections, and with and without taking into account impacts of human interventions such as dams and water withdrawals on the hydrological cycle. Model results are analyzed for different levels of global warming, allowing for analyses in line with temperature targets for climate change mitigation. The results indicate that direct human impacts on the water cycle in some regions, e.g., parts of Asia and in the western United States, are of the same order of magnitude, or even exceed impacts to be expected for moderate levels of global warming (+2 K). Despite some spread in model projections, irrigation water consumption is generally projected to increase with higher global mean temperatures. Irrigation water scarcity is particularly large in parts of southern and eastern Asia, and is expected to become even larger in the future.Terrestrial water fluxes are affected by both climate and direct human interventions, e.g., dam operations and water withdrawals. Climate change is expected to alter the water cycle and will subsequently impact water availability and demand. Several hydrologic modeling studies have focused on climate change impacts on discharge in large river basins or global terrestrial areas under naturalized conditions using a single hydrologic model forced with multiple climate projections (1, 2). Recently, hydrological projections from eight global hydrological models (GHMs) were compared (3). In many areas, there was a large spread in projected runoff changes within the climate–hydrology modeling chain. However, at high latitudes there was a clear increase in runoff, whereas some midlatitude regions showed a robust signal of reduced runoff. The study also concluded that the choice of GHM adds to the uncertainty for hydrological change caused by the choice of atmosphere–ocean general circulation models (hereafter called GCMs) (3). Expected runoff increases in the north and decreases in parts of the middle latitudes have been found also when analyzing runoff from 23 GCMs (4).These studies focused on the naturalized hydrological cycle, i.e., the effects of direct human interventions were not taken into account. However, in many river basins humans substantially alter the hydrological cycle by constructing dams and through water withdrawals. Reservoir operations alter the timing of discharge, although mean annual discharge does not necessarily change much. A study with the water balance model (WBM) showed that the impact of human disturbances, i.e., dams and water consumption, in some river basins is equal to or greater than the impact of expected climate changes on annual runoff over the next 40 y (5). Also, rising water demands are found to outweigh global warming in defining the state of global water systems in the near future (6). Water for irrigation is the largest water use sector, currently accounting for about 70% of global water withdrawals and nearly 90% of consumptive water use (7). A recent synthesis of simulations from seven GHMs found that irrigation water consumption currently amounts to 1,250 km³⋅y⁻¹ (±25%) and that considerable differences among models appear in the spatiotemporal patterns of water consumption (8).Direct comparisons of the climate impact and human intervention modeling studies can be difficult given that the setups are not identical, i.e., the input forcing data and climate models vary. Also, because of the uncertainty of model-specific results, a multimodel approach is preferable in impact modeling studies (3, 9). This approach is similar to assessments performed within the climate community. Here, multimodel results on current and future water availability and consumption at the global scale from the Water Model Intercomparison Project (WaterMIP) within the European Union Water and Global Change (EU WATCH) project (9, 10), and Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) (11) are presented. (Information on how to get access to WaterMIP and ISI-MIP simulation results can be found at www.eu-watch.org and www.isi-mip.org, respectively.) Results from these two projects are synthesized to obtain a large ensemble of impact model results. The integration of results from the different projects is achieved by extracting impacts for time periods of global mean temperature (GMT) increases of 2 and 3 K from the simulations, largely following the method of Tang and Lettenmaier (4). The advantage of this approach is that it allows presenting results in a way that is in line with temperature targets used in climate mitigation discussions.Other studies have focused on future water scarcity using results from WaterMIP and ISI-MIP, but have analyzed changes of naturalized runoff only (3, 12). We here aim to fill this knowledge gap by comparing the different impacts from climate change and direct human impacts and analyzing their interplay. The models included take into account water withdrawals and consumption in different sectors; for more information, see Models and Data and Supporting Information, SI Models and Data. The objectives of this study are to (i) assess the relative contribution of anthropogenic impacts and climate change to river basin scale water fluxes, and (ii) identify areas where climate change can be expected to cause substantial changes in water consumption and water scarcity, focusing on water for irrigation. The effects of future changes in irrigated areas or irrigation practices are not taken into account, and only dams that currently exist are included in the analyses. In this paper, simulations considering man-made reservoirs, water withdrawals, and water consumption are referred to as human impact simulations, whereas the simulations without these disturbances are referred to as naturalized simulations. The results are mainly presented in a way intended to give an overview of impacts at larger spatial scales (river basin and country levels). However, some finer-scale results are included to reveal effects that can be concealed at coarse spatial scales.