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排序方式: 共有334条查询结果,搜索用时 15 毫秒
101.
Frederic T. Billings IV Michael R. Petracek L. Jackson Roberts II Mias Pretorius 《PloS one》2015,10(2)
BackgroundCardiopulmonary bypass (CPB) lyses erythrocytes and induces lipid peroxidation, indicated by increasing plasma concentrations of free hemoglobin, F2-isoprostanes, and isofurans. Acetaminophen attenuates hemeprotein-mediated lipid peroxidation, reduces plasma and urine concentrations of F2-isoprostanes, and preserves kidney function in an animal model of rhabdomyolysis. Acetaminophen also attenuates plasma concentrations of isofurans in children undergoing CPB. The effect of acetaminophen on lipid peroxidation in adults has not been studied. This was a pilot study designed to test the hypothesis that acetaminophen attenuates lipid peroxidation in adults undergoing CPB and to generate data for a clinical trial aimed to reduce acute kidney injury following cardiac surgery.ConclusionsIntravenous acetaminophen attenuates the increase in intraoperative plasma isofuran concentrations that occurs during CPB, while urinary markers were unaffected.
Trial Registration
ClinicalTrials.gov NCT01366976相似文献102.
Mark J. Butler IV Donald C. Behringer Jr. Thomas W. Dolan III Jessica Moss Jeffrey D. Shields 《PloS one》2015,10(6)
Sociality has evolved in a wide range of animal taxa but infectious diseases spread rapidly in populations of aggregated individuals, potentially negating the advantages of their social interactions. To disengage from the coevolutionary struggle with pathogens, some hosts have evolved various forms of “behavioral immunity”; yet, the effectiveness of such behaviors in controlling epizootics in the wild is untested. Here we show how one form of behavioral immunity (i.e., the aversion of diseased conspecifics) practiced by Caribbean spiny lobsters (Panulirus argus) when subject to the socially transmitted PaV1 virus, appears to have prevented an epizootic over a large seascape. We capitalized on a "natural experiment" in which a die-off of sponges in the Florida Keys (USA) resulted in a loss of shelters for juvenile lobsters over a ~2500km2 region. Lobsters were thus concentrated in the few remaining shelters, presumably increasing their exposure to the contagious virus. Despite this spatial reorganization of the population, viral prevalence in lobsters remained unchanged after the sponge die-off and for years thereafter. A field experiment in which we introduced either a healthy or PaV1-infected lobster into lobster aggregations in natural dens confirmed that spiny lobsters practice behavioral immunity. Healthy lobsters vacated dens occupied by PaV1-infected lobsters despite the scarcity of alternative shelters and the higher risk of predation they faced when searching for a new den. Simulations from a spatially-explicit, individual-based model confirmed our empirical results, demonstrating the efficacy of behavioral immunity in preventing epizootics in this system. 相似文献
103.
Bathri N. Vajravelu Kyung U. Hong Tareq Al-Maqtari Pengxiao Cao Matthew C. L. Keith Marcin Wysoczynski Zhao John Joseph B. Moore IV Roberto Bolli 《PloS one》2015,10(10)
A recent phase I clinical trial (SCIPIO) has shown that autologous c-kit+ cardiac progenitor cells (CPCs) improve cardiac function and quality of life when transplanted into patients with ischemic heart disease. Although c-kit is widely used as a marker of resident CPCs, its role in the regulation of the cellular characteristics of CPCs remains unknown. We hypothesized that c-kit plays a role in the survival, growth, and migration of CPCs. To test this hypothesis, human CPCs were grown under stress conditions in the presence or absence of SCF, and the effects of SCF-mediated activation of c-kit on CPC survival/growth and migration were measured. SCF treatment led to a significant increase in cell survival and a reduction in cell death under serum depletion conditions. In addition, SCF significantly promoted CPC migration in vitro. Furthermore, the pro-survival and pro-migratory effects of SCF were augmented by c-kit overexpression and abrogated by c-kit inhibition with imatinib. Mechanistically, c-kit activation in CPCs led to activation of the PI3K and the MAPK pathways. With the use of specific inhibitors, we confirmed that the SCF/c-kit-dependent survival and chemotaxis of CPCs are dependent on both pathways. Taken together, our findings suggest that c-kit promotes the survival/growth and migration of human CPCs cultured ex vivo via the activation of PI3K and MAPK pathways. These results imply that the efficiency of CPC homing to the injury site as well as their survival after transplantation may be improved by modulating the activity of c-kit. 相似文献
104.
105.
John P. Morris IV Renee Greer Holger A. Russ Guido von Figura Grace E. Kim Anke Busch Jonghyeob Lee Klemens J. Hertel Seung Kim Michael Mcmanus Matthias Hebrok 《PloS one》2014,9(5)
miRNA levels are altered in pancreatic ductal adenocarcinoma (PDA), the most common and lethal pancreatic malignancy, and intact miRNA processing is essential for lineage specification during pancreatic development. However, the role of miRNA processing in PDA has not been explored. Here we study the role of miRNA biogenesis in PDA development by deleting the miRNA processing enzyme Dicer in a PDA mouse model driven by oncogenic Kras. We find that loss of Dicer accelerates Kras driven acinar dedifferentiation and acinar to ductal metaplasia (ADM), a process that has been shown to precede and promote the specification of PDA precursors. However, unconstrained ADM also displays high levels of apoptosis. Dicer loss does not accelerate development of Kras driven PDA precursors or PDA, but surprisingly, we observe that mouse PDA can develop without Dicer, although at the expense of proliferative capacity. Our data suggest that intact miRNA processing is involved in both constraining pro-tumorigenic changes in pancreatic differentiation as well as maintaining viability during PDA initiation. 相似文献
106.
Many autotrophs vary their allocation to nutrient uptake in response to environmental cues, yet the dynamics of this plasticity
are largely unknown. Plasticity dynamics affect the extent of single versus multiple nutrient limitation and thus have implications
for plant ecology and biogeochemical cycling. Here we use a model of two essential nutrients cycling through autotrophs and
the environment to determine conditions under which different plastic or fixed nutrient uptake strategies are adaptive. Our
model includes environment-independent costs of being plastic, environment-dependent costs proportional to the rate of plastic
change, and costs of being mismatched to the environment, the last of which is experienced by both fixed and plastic types.
In equilibrium environments, environment-independent costs of being plastic select for tortoise strategies—fixed or less plastic
types—provided that they are sufficiently close to co-limitation. At intermediate levels of environmental fluctuation forced
by periodic nutrient inputs, more hare-like plastic strategies prevail because they remain near co-limitation. However, the
fastest is not necessarily the best. The most adaptive strategy is an intermediate level of plasticity that keeps pace with
environmental fluctuations, but is not faster. At high levels of environmental fluctuation, the environment-dependent cost
of changing rapidly to keep pace with the environment becomes prohibitive and tortoise strategies again dominate. The existence
and location of these thresholds depend on plasticity costs and rate, which are largely unknown empirically. These results
suggest that the expectations for single nutrient limitation versus co-limitation and therefore biogeochemical cycling and
autotroph community dynamics depend on environmental heterogeneity and plasticity costs. 相似文献
107.
Walter H. Adey H. Dail Laughinghouse IV John B. Miller Lee‐Ann C. Hayek Jesse G. Thompson Steven Bertman Kristin Hampel Shanmugam Puvanendran 《Journal of phycology》2013,49(3):489-501
Two Algal Turf Scrubber (ATS) units were deployed on the Great Wicomico River (GWR) for 22 months to examine the role of substrate in increasing algal productivity and nutrient removal. The yearly mean productivity of flat ATS screens was 15.4 g · m?2 · d?1. This was elevated to 39.6 g · m?2 · d?1 with a three‐dimensional (3‐D) screen, and to 47.7 g · m?2 · d?1 by avoiding high summer harvest temperatures. These methods enhanced nutrient removal (N, P) in algal biomass by 3.5 times. Eighty‐six algal taxa (Ochrophyta [diatoms], Chlorophyta [green algae], and Cyan‐obacteria [blue–green algae]) self‐seeded from the GWR and demonstrated yearly cycling. Silica (SiO2) content of the algal biomass ranged from 30% to 50% of total biomass; phosphorus, nitrogen, and carbon content of the total algal biomass ranged from 0.15% to 0.21%, 2.13% to 2.89%, and 20.0% to 25.7%, respectively. Carbohydrate content (at 10%–25% of AFDM) was dominated by glucose. Lipids (fatty acid methyl ester; FAMEs) ranged widely from 0.5% to 9% AFDM, with Omega‐3 fatty acids a consistent component. Mathematical modeling of algal produ‐ctivity as a function of temperature, light, and substrate showed a proportionality of 4:3:3, resp‐ectively. Under landscape ATS operation, substrate manipulation provides a considerable opportunity to increase ATS productivity, water quality amelioration, and biomass coproduction for fertilizers, fermentation energy, and omega‐3 products. Based on the 3‐D prod‐uctivity and algal chemical composition demonstrated, ATS systems used for nonpoint source water treat‐ment can produce ethanol (butanol) at 5.8× per unit area of corn, and biodiesel at 12.0× per unit area of soy beans (agricultural production US). 相似文献
108.
109.
Tobacco callus grown under shoot-forming conditions or in the presence of gibberellic acid, which inhibits shoot formation, was incubated in [14 C]-sucrose at three different periods in culture and then replanted. Evolution of 14 CO2 occurred during the 10 day post-incubation period. Most of the radioactivity was incorporated into the ethanol-soluble fraction, which lost most of its label after 24 h. Starch was the major ethanol-insoluble component and post-incubation synthesis occurred in this fraction for 24 h or longer. Greater net synthesis of starch occurred in shoot-forming tissue and the loss of label from starch began later than in tissue cultured in the presence of gibbe-rellic acid. Newly synthesized starch was not immediately utilised in the organogenic process, but its utilization could be correlated with the shoot-forming process. 相似文献
110.
The observed range for temporal mean-variance scaling exponents can be explained by reproductive correlation 总被引:1,自引:0,他引:1
The mean-variance scaling relationship known as Taylor's power law has been well documented empirically over the past four decades but a general theoretical explanation for the phenomenon does not exist. Here we provide an explanation that relates empirical patterns of temporal mean-variance scaling to individual level reproductive behavior. Initially, we review the scaling behavior of population growth models to establish theoretical limits for the scaling exponent b that is in agreement with the empirically observed range (1≤b≤2). We go on to show that the degree of reproductive covariance among individuals determines the scaling exponent b. Independent reproduction results in an exponent of one, while completely correlated reproduction results in the upper limit of two. Intermediate exponents, which are common empirically, can be generated through the decay of reproductive covariance with increasing population size. Finally, we describe how the link between reproductive correlation and the scaling exponent provides a way to infer properties of individual-level reproductive behavior, such as the relative influence of demographic stochasticity, from a macroecological pattern. 相似文献