bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear factor‐κB regulates seizure threshold and gene transcription following convulsant stimulation
Authors: Lubin Farah D. , Ren Yajun , Xu Xianghua , Anderson Anne E. 
Published: September 2007

AbstractWe evaluated a role for the nuclear factor‐kappa B (NF‐κB) pathway in the regulation of seizure susceptibility and transcriptional activation during prolonged, continuous seizures (status epilepticus). Using two functionally distinct NF‐κB inhibitors we observed a decrease in latency to onset of kainate‐induced seizures and status epilepticus. To assess NF‐κB transcriptional activation, we evaluated inhibitor kappa B alpha (IκBα) and brain‐derived neurotrophic factor (bdnf) gene targets. Inhibition of the NF‐κB signaling pathway significantly attenuated the increases in IκBα and bdnf mRNA levels that occurred during prolonged seizure activity, suggesting that the NF‐κB pathway was involved in the up‐regulation of these transcripts during status epilepticus. DNA‐binding studies and chromatin immunoprecipitation assays using hippocampal extracts from animals with status epilepticus revealed that NF‐κB subunits were associated with the candidate κB‐binding elements within promoter 1 of the bdnf gene. The pattern of association was different for the p50 and p65 subunits supporting complex NF‐κB modifications within promoter 1. In summary, our findings provide additional insights into the role of NF‐κB transcriptional regulation in hippocampus following status epilepticus and suggest that NF‐κB pathway activation contributes to seizure susceptibility.
Neuroprotection and stroke: time for a compromise
Authors: Young Alan R. , Ali Carine , Duretête Arnaud , Vivien Denis 
Published: September 2007

AbstractIn April 2007, there existed a repertory of 286 trials concerned with acute ischemic stroke on the Stroke Trials Registry (http://www.strokecenter.org/trials/), of which 209 trials were considered as complete (with no evidence of patient benefit unless one considers the much hard fought for and modest results of the tPA studies). Among other questions arising from such failures, one can wonder whether the plethora of pharmacological agents that exhibited neuroprotective properties in pre‐clinical studies were selected for clinical trials entirely based upon their experimental efficacy. This mini‐review will try to point out some of the weaknesses that could underline the failure of both researchers and clinicians involved in the field of stroke to obtain their ultimate goal – brain protection.
Formyl peptide‐receptor like‐1 requires lipid raft and extracellular signal‐regulated protein kinase to activate inhibitor‐κB kinase in human U87 astrocytoma cells
Authors: Kam Angel Y. F. , Liu Andrew M. F. , Wong Yung H. 
Published: September 2007

AbstractFormyl peptide‐receptor like‐1 (FPRL‐1) may possess critical roles in Alzheimer’s diseases, chemotaxis and release of neurotoxins, possibly through its regulation of nuclear factor‐κB (NFκB). Here we illustrate that activation of FPRL‐1 in human U87 astrocytoma or Chinese hamster ovary cells stably expressing the receptor resulted in the phosphorylations of inhibitor‐κB kinase (IKK), an onset kinase for NFκB signaling cascade. FPRL‐1 selective hexapeptide Trp‐Lys‐Tyr‐Met‐Val‐Met (WKYMVM) promoted IKK phosphorylations in time‐ and dose‐dependent manners while pre‐treatment of pertussis toxin abrogated the Gαi/o‐dependent stimulations. The FPRL‐1‐mediated IKK phosphorylation required extracellular signal‐regulated protein kinase (ERK), phosphatidylinositol 3‐kinase and cellular Src (c‐Src), but not c‐Jun N‐terminal kinase and p38 mitogen‐activated protein kinase. Despite its ability to mobilize Ca2+, WKYMVM did not require Ca2+for the modulation of IKK phosphorylation. Activation of FPRL‐1 also induced NFκB‐driven luciferase expression. Interestingly, cholesterol depletion from plasma membrane by methyl‐β‐cyclodextrin abolished the FPRL‐1‐stimulated IKK phosphorylation, denoting the important role of lipid raft integrity in the FPRL‐1 to IKK signaling. Furthermore, we demonstrated that in U87 cells, several signaling intermediates in the FPRL‐1‐IKK pathway including Gαi2, c‐Src and ERK were constitutively localized at the raft microdomains. WKYMVM administration not only resulted in higher amount of ERK recruitment to the raft region, but also specifically stimulated raft‐associated c‐Src and ERK phosphorylations. Taken together, these results demonstrate that FPRL‐1 is capable of activating NFκB signaling through IKK phosphorylation and this may serve as a useful therapeutical target for FPRL‐1‐related diseases.
Magnetic resonance analysis of the effects of acute ammonia intoxication on rat brain. Role of NMDA receptors
Authors: Cauli Omar , López‐Larrubia Pilar , Rodrigues Tiago B. , Cerdán Sebastián , Felipo Vicente 
Published: September 2007

AbstractAcute ammonia intoxication leads to rapid death, which is prevented by blocking N‐methyl‐d‐aspartate (NMDA) receptors. The subsequent mechanisms leading to death remain unclear. Brain edema seems an important step. The aim of this work was to study the effects of acute ammonia intoxication on different cerebral parameters in vivo using magnetic resonance and to assess which effects are mediated by NMDA receptors activation. To assess edema induction, we injected rats with ammonium acetate and measured apparent diffusion coefficient (ADC) in 16 brain areas. We also analyzed the effects on T1, T2, and T2* maps and whether these effects are prevented by blocking NMDA receptors. The effects of acute ammonia intoxication are different in different brain areas. T1 relaxation time is reduced in eight areas. T2 relaxation time is reduced only in ventral thalamus and globus pallidus. ADC values increased in hippocampus, caudate‐putamen, substantia nigra and cerebellar cortex, reflecting vasogenic edema. ADC decreased in hypothalamus, reflecting cytotoxic edema. Myo‐inositol increased in cerebellum and substantia nigra, reflecting vasogenic edema. N‐acetyl‐aspartate decreased in cerebellum, reflecting neuronal damage. Changes in N‐acetyl‐aspartate, T1 and T2 are prevented by blocking NMDA receptors with MK‐801 while changes in ADC or myo‐inositol (induction of edema) are not.
Cell death in an ischemic infarct rim model
Authors: Yao Hang , Sun Xiaolu , Gu Xiang , Wang Juan , Haddad Gabriel G. 
Published: September 2007

AbstractUsing an in vitro model that simulates the microenvironment in the ischemic infarct rim, we have examined the temporal profile and possible mechanisms of cell death in the neuropil (an astrocyte‐rich area or ARA) of organotypic hippocampal slice cultures. Two‐photon confocal microscopy, propidium iodide, and GFAP‐GFP transgenic mice were used to confirm cell death in astrocytes. An ‘ischemic solution’ (IS) induced major cell death throughout the hippocampus over 24 h, with the earliest injury starting in ARA. Our studies using IS or ion replacements in IS revealed that cell death in ARA was modest when K+ was increased or pH lowered. High K+ is most effective in reducing cell death when HCO3− is normal or high. When Cl− or HCO3− was reduced, cell injury was worsened. 4,4′‐diisothiocyanatostilbene‐2,2′‐disulfonic acid (DIDS) protected cells from IS‐induced death in a dose‐dependent manner (1–4000 μmol/L). We conclude that (i) various areas of the hippocampal formation respond differently to ionic replacements; (ii) K+ interacts with other ions to protect cells in ARA; and (iii) DIDS has a substantial protective effect in ARA by blocking DIDS‐sensitive membrane exchangers or by interfering with intracellular signaling pathways.
Aldose reductase is implicated in high glucose‐induced oxidative stress in mouse embryonic neural stem cells
Authors: Fu Jiang , Tay S. S. W. , Ling E. A. , Dheen S. T. 
Published: September 2007

AbstractOxidative stress caused by hyperglycemia is one of the key factors responsible for maternal diabetes‐induced congenital malformations, including neural tube defects in embryos. However, mechanisms by which maternal diabetes induces oxidative stress during neurulation are not clear. The present study was aimed to investigate whether high glucose induces oxidative stress in neural stem cells (NSCs), which compose the neural tube during development. We also investigated the mechanism by which high glucose disturbs the growth and survival of NSCs in vitro. NSCs were exposed to physiological d‐glucose concentration (PG, 5 mmol/L), PG with l‐glucose (25 mmol/L), or high d‐glucose concentration (HG, 30 or 45 mmol/l). HG induced reactive oxygen species production and mRNA expression of aldose reductase (AR), which catalyzes the glucose reduction through polyol pathway, in NSCs. Expression of glucose transporter 1 (Glut1) mRNA and protein which regulates glucose uptake in NSCs was increased at early stage (24 h) and became down‐regulated at late stage (72 h) of exposure to HG. Inhibition of AR by fidarestat, an AR inhibitor, decreased the oxidative stress, restored the cell viability and proliferation, and reduced apoptotic cell death in NSCs exposed to HG. Moreover, inhibition of AR attenuated the down‐regulation of Glut1 expression in NSCs exposed to HG for 72 h. These results suggest that the activation of polyol pathway plays a role in the induction of oxidative stress which alters Glut1 expression and cell cycle in NSCs exposed to HG, thereby resulting in abnormal patterning of the neural tube in embryos of diabetic pregnancy.
PERMANENT GENETIC RESOURCES: Characterization of eight microsatellite loci in the woolly mouse opossum, Micoureus paraguayanus, isolated from Micoureus demerarae
Authors: DIAS I. M. G. , AMATO G. , CARVALHO M. R. S. , CUNHA H. M. , PAGLIA A. P. , DESALLE R. , FONSECA C. G. 
Published: September 2007

AbstractEight novel microsatellite markers were isolated from the woolly mouse opossum from the Amazon Forest in Peru, Micoureus demerarae, using a partial genomic DNA library and an enrichment protocol. These loci were polymorphic in M. demerarae and Micoureus paraguayanus populations from the Atlantic Forest in Brazil with the number of alleles ranging from two to 23. Those eight loci plus another five already described for M. paraguayanus will allow for the evaluation of genetic diversity of populations from the ‘Rio Doce’ Park, one of the last Atlantic Forest fragments in Minas Gerais state, Brazil.
PERMANENT GENETIC RESOURCES: A set of 12 microsatellite loci for genetic studies of Leishmania braziliensis
Authors: ROUGERON V. , WALECKX E. , HIDE M. , DE MEEÛS T. , AREVALO J. , LLANOS‐CUENTAS A. , BAÑULS A. L. 
Published: September 2007

AbstractTwelve microsatellite loci of Leishmania braziliensis were examined, nine of which were developed in this work. Fifty‐six Leishmania braziliensis were genotyped with these microsatellite loci. The 12 loci studied were polymorphic with the number of alleles ranging from five to 19, with a mean of 9.7 ± 4.1 and the observed heterozygosity averaging 0.425 ± 0.202. The important heterozygote deficits we observed (FIS = 0.41, P value = 0.004) appear incompatible with the heterozygote excess expected in clonal diploids. This last result could revive the clonality/sexuality debate regarding Leishmania. This work validates the potential use of these microsatellites for population genetics analysis.
Effects of tillage and reseeding on phosphorus transfers from grassland
Authors: Butler P. J. , Haygarth P. M. 
Published: September 2007

AbstractPasture tillage and reseeding is part of the normal rotation cycle of grassland systems in the UK and a process that could increase the rate of phosphorus (P) transfer to water, thus potentially contributing to eutrophication. The effect of tillage and reseeding on P transfer was investigated at two scales: from drained and undrained 1 ha hydrologically isolated pasture plots within the Rowden Drainage Experiment in Devon, during a 6‐month winter drainage period in 1998–1999, and in replicated soil box experiments during simulated rainfall ‘events’. At the plot scale, total P exports of 3.75 kg P ha−1 were determined over a 16‐day period, indicating that soil and P were most vulnerable to detachment and mobilization during rainfall and run‐off in this period. Once the sward had developed, and the vulnerability to soil detachment reduced, reseeded swards with pipe drainage transferred less P (approx. 0.3 kg P ha−1 yr−1) to water than is commonly measured on permanent grassland (approx. 1 kg P ha−1 yr−1). Soil box experiments showed that tilled soil transferred more P > 0.45 μm but P < 0.45 μm was retained. Sward cover is critical to reducing detachment and resulting P transfer from surface soil, and therefore careful consideration should be taken for the need to reseed. The effects of tillage and reseeding on phosphorus transfers from grassland can be potentially significant and ought to be mitigated against using low‐till practices to reduce potential contribution to water quality.
Soil texture effects on the transport of phosphorus from agricultural land in river deltas of Northern Belgium, The Netherlands and North‐West Germany
Authors: Chardon W. J. , Schoumans O. F. 
Published: September 2007

AbstractThe loss of phosphorus (P) from agricultural soils can lead to serious eutrophication of surface water. Within the large river delta areas in Northern Belgium, The Netherlands and North‐West Germany, a number of representative soil textures are found (sandy, peaty and clayey soils), each with its own specific combination of pathways for P loss. Based on a literature review, this paper describes for these areas the main eutrophication issues and the factors affecting P loss from these agricultural soils. Aspects of P input, legislation and water quality are discussed. On sandy soils, intensive animal production systems have led to the localized build‐up of P in the soil profile with subsequent leaching to shallow groundwaters, and seepage into surface waters. Regulations for production and application of manure on these soils have led to improvements in surface water quality in the last decade, but P concentrations are still too high to maintain satisfactory ecological standards in water. On peat soils, the mineralization of organic matter in the topsoil or in the subsoil can release large amounts of P, leading to high concentrations of P in surface water. However, large P losses can also occur in seepage water from peat deposits in marine sediments containing easily‐soluble calcareous P minerals. On clays, incidental losses of P are dominant: surface runoff or preferential flow can lead to loss of freshly applied P, even from soils that are known to have a large retention capacity for P.
Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe
Authors: Csathó P. , Sisák I. , Radimszky L. , Lushaj S. , Spiegel H. , Nikolova M. T. , Nikolov N. , ČErmák P. , Klir J. , Astover A. , Karklins A. , Lazauskas S. , Kopiński J. , Hera C. , Dumitru E. , Manojlovic M. , Bogdanović D. , Torma S. , Leskošek M. , Khristenko A. 
Published: September 2007

AbstractThere are considerable differences between the EU‐15 countries and Central and Eastern European (CEE) countries in the application rate of phosphorus (P) fertilizer and manure as well as in the climate and erosion patterns, but the eutrophication of surface waters is a common problem. The availability of information on the contribution of the CEE countries to European surveys on eutrophication is not adequate, because the amount of data available from these countries is small. There is thus a need to compile more comprehensive data sets for better assessment. Recent changes in agricultural practices, and their impact on the trophic status of surface waters in CEE countries, have been evaluated using a few selected pressure and state indicators (phosphorus balance, phosphorus status and erosion of agricultural land, P loss risk index, chlorophyll a, total and orthophosphate content of water) by compiling and analysing data from the literature. In the CEE countries, small annual P balances (−7 to +6 kg P ha−1) and declining levels of soil available P (proportion of soils adequately supplied with P dropped to between 10 and 50% of total area) may lead to low yields and economic difficulties. Only 11% of the variation in total phosphorus (TP) in rivers studied could be attributed to the calculated P loss risk index, and thus to the impact of differences in the agricultural diffuse source P load. The generation of more consistent data sets should be pursued for the whole of Europe in order to derive more powerful indicators. A refined P index could be one of the best indicators of eutrophication. Recent changes in the trophic level of surface waters could be attributed to a large extent to the change in point source P loads, i.e. to the diminishing amount of P load from municipal and industrial wastewater. The short‐term improvement of water quality in the CEE countries will require further improvements in wastewater treatment, but long‐term improvement will only be achieved by reducing diffuse P losses from agriculture, possibly involving changes in the land use pattern and in farming practices.
Linking phosphorus sources to impacts in different types of water body
Authors: Edwards A. C. , Withers P. J. A. 
Published: September 2007

AbstractThe inherent variability in type, composition and modes of transport/delivery of the various sources of phosphorus (P) contribute to the complex temporal and spatial patterns of P concentrations and loads reaching freshwaters. One particularly useful and common distinction is made between diffuse sources that are hydrologically driven and therefore episodic and seasonal, compared with the more bioavailable, concentrated and continuous P discharges from discrete point sources. In terms of ecological impacts, well‐distributed rural point sources (village wastewater, septic tank overflows and farmyards) that discharge into smaller tributaries may be further separated from the more isolated large urban wastewater and industrial effluent discharges to larger waters. Impacts of diffuse sources may be similarly broken down into near‐surface and base flow (groundwater) contributions. These differences in mechanisms of delivery, when coupled with differences in chemical form (and therefore availability) of P, combine to influence in‐stream processes, kinetics of downstream transport and potential impacts. A greater understanding of the specific attributes that are responsible for controlling the dynamics of a particular P source together with some idea of its environmental relevance would help prioritize and target remedial actions. In particular, the extent to which periods of P supply overlap with those of biological demand help determine the relative significance of individual P sources and could inform programmes of measures to control P loss from these sources more effectively. The lack of any provision for interpreting P supply within an ecological context might result in poor relationships between reductions in P loading and environmental benefit.
Variation in the reactive phosphorus concentrations in rivers of northwest Europe with respect to their potential to cause eutrophication
Authors: Foy R. H. 
Published: September 2007

AbstractBy 2002, there had been a variable implementation of phosphorus (P) removal at waste water treatment works in a set of countries in northwest Europe; ranging from close to 100% of the urban populations in Austria, Denmark, Finland, Germany, the Netherlands and Sweden to between 2% and 56% of the inland urban populations in Belgium, France, Ireland and the UK. This variable application has resulted in a proportional lowering of reactive phosphorus (RP) concentrations in rivers. Thus, although the inland urban population density of Germany exceeds that of the UK (207 vs. 148 persons km−2), mean RP in 2004 was lower in German rivers (75 vs. 265 μg P L−1). By adjusting urban populations downwards by the P equivalent populations removed through tertiary treatment, the resulting effective urban population density was strongly and positively correlated with mean river RP concentration (r = 0.99) and the percentage of rivers with average RP >100 μg P L−1 (r = 0.98). Two agricultural variables, the agricultural area as a percentage of total area and the application of P in manures and fertilizers to the national land area were uncorrelated with either mean or median RP concentrations but were negatively correlated with the proportion of rivers with low mean concentrations of RP (<25 μg P L−1). Phosphorus discharges associated with urban populations remains the strongest driver of a time‐weighted variable such as average RP concentration, although agricultural variables may exert a stronger influence on flow‐weighted concentrations or loadings of RP.
Sourcing, transport and control of phosphorus loss in two English headwater catchments
Authors: Hodgkinson R. A. , Withers P. J. A. 
Published: September 2007

AbstractLong‐term data on annual phosphorus (P) transfers from an intensively under‐drained largely arable catchment (Rosemaund) and a less intensively drained mixed arable/dairy catchment (Cliftonthorpe) are presented and compared. The range in stream loads of total P (TP) from both catchments was very similar (0.1–4.2 kg ha−1 year−1) and dominated by the particulate (PP) form. At Rosemaund, the majority (approx. 55%) of the P was transferred through pipe drains. The PP transfers in overland flow from arable fields at Rosemaund were estimated to be three times those from extensive grassland and the contribution of hopyards was over 10 times that of arable land. Changing land use from arable to grass at Rosemaund reduced flow and P loss through pipe drains, especially in the third year after establishment. By contrast, at Cliftonthorpe, only 33% of the TP transfer was through pipe drains and PP transfers in overland flow from grassland were estimated to be twice that from arable land. The increased P transfer from grassland was related to livestock poaching mobilizing P on wet riparian fields. However, establishment of a 6‐m riparian grass buffer strip at Cliftonthorpe had no beneficial effect on TP transfer over a 3‐year period and tended to increase the proportion of P transferred in soluble form. Our data highlight the large variability in P loss risk due to land management rather than land use per se, and the potential for PP transfer to occur from grassland as well as from arable land. More long‐term research is needed to fully evaluate the effectiveness of control options in catchments.