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101.
The aim of the study was to determine the prevalence of Echinococcus multilocularis in red foxes (Vulpes vulpes) in Poland. Overall, 1,546 intestinal samples from 15 of the 16 provinces in Poland were examined by the sedimentation and counting technique (SCT). The mean prevalence of E. multilocularis in Poland was 16.5 % and was found in 14 of the 15 examined provinces. The mean intensity of infection was 2,807 tapeworms per intestine. Distinct differences in prevalence were observed between regions. In some provinces of eastern and southern Poland, the level of prevalence was 50.0 % (Warmińsko-Mazurskie), 47.2 % (Podkarpackie), 30.4 % (Podlaskie) and 28.6 % (Ma?opolskie), while in other provinces (west and south-west), only a few percent was found: 2.0 % (Dolno?l?skie), 2.5 % (Wielkopolskie) and 0.0 % (in Opolskie). The border between areas with higher and lower prevalence seems to coincide with a north–south line running through the middle of Poland, with prevalence from 17.5 to 50.0 % in the eastern half and from 0.0 to 11.8 % in the western half. The dynamic situation observed in the prevalence of this tapeworm indicated the necessity of continuing to monitor the situation concerning E. multilocularis in red foxes in Poland.  相似文献   
102.
Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 °C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics.After acquisition via photosynthesis (gross primary production), new plant carbon (C) is respired, transferred to mycorrhizal symbionts, exuded, or converted into new biomass (net primary production). The new biomass can be foliage, stems (including boles, branches, and bark), roots, or reproductive parts. The proportional allocation of new C to these four plant biomass pools, when combined with their turnover rates, results in the proportional distribution of standing biomass among these pools. Such processes can be influenced by plant size, resource supply, and/or climate (110). Although simple in concept, our understanding of these processes and our ability to quantify and predict them remain surprisingly rudimentary (313).The general lack of knowledge about C partitioning is important for a number of reasons, including its implications for the accuracy of global C cycle modeling and accounting. A recent study (11) concluded
different carbon partitioning schemes resulted in large variations in estimates of global woody carbon flux and storage, indicating that stand-level controls on carbon partitioning are not yet accurately represented in ecosystem models.
Uncertainty about C partitioning in relation to biogeography and environmental effects is a particularly critical knowledge gap, because the direct and indirect influence of temperature or moisture availability on biomass partitioning could be important to growth, nutrient cycling, productivity, ecosystem fluxes, and other key plant and ecosystem processes (5, 710, 12). Additionally, uncertainty about belowground C allocation and biomass dynamics represents a major information gap that hampers efforts to estimate belowground C pools at continental to global scales (cf. 13 and 14).Some of the limited evidence available supports the hypothesis that under low temperatures both selection and phenotypic plasticity should promote a relatively greater fraction of forest biomass in roots (5, 7, 8, 12, 1518), as a result of adaptation to low nutrient supply (7, 1922) driven by low nutrient cycling rates and limited soil solution movement. Cold environments also are often periodically dry and exhibit low plant production (1926). Belowground resource limitations obviously also rise with increasing shortage of rainfall relative to evaporative demand, which can influence biomass distribution as well (4, 5, 17). Uncertainties include whether there are differences across climate gradients in the fraction of gross primary production respired vs. converted into new biomass; how new biomass is partitioned to foliage, stems, and roots; what the turnover rates are for these different tissues; and what are the consequences of the biomass distribution in foliage, stem, and root. In this study we focus on the last uncertainty—biomass distributions in standing pools—which is a direct consequence of new biomass allocation and subsequent turnover rate. Following optimal partitioning theory (14), we posit that the fraction of total forest biomass in roots should increase and in foliage should decrease when belowground resources are scarce.We use a large dataset based on more than 6,200 observations of forest stands in 61 countries (Tables S1–S3 and Fig. 1) to test the following hypotheses: (i) with increasing temperature, proportional biomass distribution (i.e., fraction of total biomass) should decrease in roots and increase in foliage; (ii) with increasing water shortage (estimated by an index of rainfall to evaporative demand), proportional biomass distribution should increase in roots and decrease in foliage; and (iii) gymnosperm and angiosperm forests should follow similar patterns. The dataset comprises data entries for individual stands including total foliage mass per hectare (Mfol), total stem mass per hectare (Mstem), total root mass per hectare (Mroot), and, where available, total mass per hectare (Mtot = Mfol + Mstem + Mroot). Forests were either naturally regenerated or plantations. Stands were classified as gymnosperm or angiosperm based on whichever represented a greater fraction of basal area or biomass; almost all native forests were of mixed species.Open in a separate windowFig. 1.Map showing location of all stands in the assembled database (see Tables S1 and S2 for additional information specific to those with root, foliage, and stem biomass data or with foliage and stem biomass data) across color-coded ranges of MAT.The sampled forests varied widely in age (from 3–400 y) and size (with Mtot ranging from near zero to 300 Mg/ha). Differences in biomass (which we refer to as size) reflect differences in productivity, density, and especially the range of ages of sampled stands. Because tree-size scaling is allometric (3, 4, 7, 9), we use an allometric approach to account for size-related changes in biomass partitioning in examining broad biogeographic patterns. Forests with high biomass have larger trees on average than forests with low biomass (given that tree density typically is lower in the former), so the forest size allometry characterized herein likely has its roots at the individual tree scale, but our analyses use stand Mtot, not individual tree biomass. We also examine biogeographic differences in the fraction of Mtot in foliage (Ffol), stem (Fstem), and root (Froot).The term “allocation” has been used historically to describe both the onward distribution, or flux, of newly acquired substances (usually C or biomass) to different plant functions and differences in how those pools are distributed at any point in time. To minimize confusion about these different measures. we hereafter use the term “allocation” along with “new biomass” or “new C” only to indicate the former and discuss either the proportion of biomass or the fraction of biomass distributed in foliage, stems, or roots to indicate the latter.The sampled forests varied widely geographically and in mean annual temperature (MAT) (from −13 to 29 °C) and mean annual precipitation (MAP) (from 20–420 cm) (Tables S1 and S2 and Fig. 1). Because a number of seasonal and annual climatic factors covary, it is difficult to ascertain which are responsible for the observed patterns (Materials and Methods and SI Materials and Methods). Because MAP is strongly correlated with MAT and is not a good global measure of water availability, we used an aridity index, the ratio of MAP to annual potential evapotranspiration (MAP/PET) (27) as a measure of relative water availability. MAP/PET ranged from <0.5 in cold, high-latitude zones to >3 in temperate and tropical rainforests. The forests ranged from sea level to >4,000 m elevation, with the large majority at <1,000 m elevation. More sampled forests were from Asia and Europe than other continents, and more were boreal and temperate than tropical. Thus, inferences from these data are likely to be most reliable across the gradient from subtropical to cold boreal forests.  相似文献   
103.
Polychlorinated biphenyls (PCBs) are toxic environmental pollutants. Humans are exposed to PCB mixtures via contaminated food or water. PCB exposure causes adverse effects in adults and after exposure in utero. PCB toxicity depends on the congener mixture and CYP1A2 gene activity. For coplanar PCBs, toxicity depends on ligand affinity for the aryl hydrocarbon receptor (AHR). Previously, we found that perinatal exposure of mice to a three‐coplanar/five‐noncoplanar PCB mixture induced deficits in novel object recognition and trial failures in the Morris water maze in Cyp1a2?/?::Ahrb1 C57BL6/J mice compared with wild‐type mice (Ahrb1 = high AHR affinity). Here we exposed gravid Cyp1a2?/?::Ahrb1 mice to a PCB mixture on embryonic day 10.5 by gavage and examined the F1 and F3 offspring (not F2). PCB‐exposed F1 mice exhibited increased open‐field central time, reduced acoustic startle, greater conditioned contextual freezing and reduced CA1 hippocampal long‐term potentiation with no change in spatial learning or memory. F1 mice also had inhibited growth, decreased heart rate and cardiac output, and impaired fertility. F3 mice showed few effects. Gene expression changes were primarily in F1 PCB males compared with wild‐type males. There were minimal RNA and DNA methylation changes in the hippocampus from F1 to F3 with no clear relevance to the functional effects. F0 PCB exposure during a period of rapid DNA de‐/remethylation in a susceptible genotype produced clear F1 effects with little evidence of transgenerational effects in the F3 generation. While PCBs show clear developmental neurotoxicity, their effects do not persist across generations for effects assessed herein.  相似文献   
104.
Understanding the benefits and risks of treatments to be used by older individuals (≥65 years old) is critical for informed therapeutic decisions. Glucose-lowering therapy for older patients with diabetes should be tailored to suit their clinical condition, comorbidities and impaired functional status, including varying degrees of frailty. However, despite the rapidly growing population of older adults with diabetes, there are few dedicated clinical trials evaluating glucose-lowering treatment in older people. Conducting clinical trials in the older population poses multiple significant challenges. Despite the general agreement that individualizing treatment goals and avoiding hypoglycaemia is paramount for the therapy of older people with diabetes, there are conflicting perspectives on specific glycaemic targets that should be adopted and on use of specific drugs and treatment strategies. Assessment of functional status, frailty and comorbidities is not routinely performed in diabetes trials, contributing to insufficient characterization of older study participants. Moreover, significant operational barriers and problems make successful enrolment and completion of such studies difficult. In this review paper, we summarize the current guidelines and literature on conducting such trials, as well as the learnings from our own clinical trial (IMPERIUM) that assessed different glucose-lowering strategies in older people with type 2 diabetes. We discuss the importance of strategies to improve study design, enrolment and attrition. Apart from summarizing some practical advice to facilitate the successful conduct of studies, we highlight key gaps and needs that warrant further research.  相似文献   
105.
106.
Kulawik T  Kałuża B  Kuśnierz J 《Kardiologia polska》2012,70(2):190-2; discussion 193
We present a case of 44 year-old female who was admitted to the hospital due to performed radio frequency ablation because of VF during WPW syndrome, which was complicated by dissection of left main. The dissection was treated with success by primary percutaneous coronary intervention with two metal stents.  相似文献   
107.
108.
Periodontitis may affect atherosclerosis via the chronic inflammation. We investigated high-sensitivity C-reactive protein (hsCRP) in relation to early vascular atherosclerotic changes in non-symptomatic subjects with and without long-term periodontitis. Carotid ultrasonography with calculation of common carotid artery intima-media area (cIMA) was performed, and hsCRP and atherosclerosis risk factors were analysed in randomly chosen 93 patients with periodontitis and 41 controls. The relationship between hsCRP, cIMA and atherosclerosis risk factors was evaluated with multiple logistic regression analysis. Women displayed lower hsCRP (p < 0.05) and higher serum HDL (p < 0.001) than men. In all patients with periodontitis, cIMA values were higher than in controls. Periodontitis appeared to be a major predictor for increased cIMA (odds ratio, 3.82; 95% confidence interval, 1.19–12.26). Neither of these factors was significantly associated with hsCRP which thus appeared not sensitive enough to be a marker for periodontitis or atherosclerosis. Hence, irrespective of low hsCRP levels, periodontitis appeared to increase the risk for atherosclerosis.  相似文献   
109.
110.
The performance of two histidine-rich protein type-2-based malaria rapid diagnostic tests (mRDTs) was examined in a rural area with a high prevalence of malaria and human immunodeficiency virus type-1 (HIV-1) infection in 113 and 445 febrile patients ≥ 15 years of age with and without HIV-1 infection, respectively. Patients were tested for HIV-1 infection by using a standard assay and for Plasmodium falciparum by using two mRDTs and microscopy. When microscopy was used as the gold standard, both mRDTs performed similarly in patients with and without HIV-1 infection: Bioline SD Malaria Antigen P.f, sensitivity 94.4% (95% confidence interval [CI]: 81.3-99.3%) versus 97.1% (95% CI:92.8-99.2%) and specificity 50.6% (95% CI: 39.0-62.2%) versus 47.2% (95% CI: 41.4-53.1%); and ICT diagnostics Malaria Pf, sensitivity 94.4% (95% CI: 81.3-99.3%) versus 97.1% (95% CI: 92.8-99.2%) and specificity 50.6% (95% CI:39.0-62.2%) versus 50.3% (95% CI: 44.4-56.1%). Infection with HIV-1 does not appear to affect the performance of these histidine-rich protein type-2 (HRP-2)-based mRDTs.  相似文献   
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