20-m resolution longitudinal nitrate data from before and after rainfall in low-order streams spanning rural to urban gradients.

This study aimed to provide datasets useful for identifying and disentangling any complex patterns in the fine spatial heterogeneity of a common nonpoint source pollutant, nitrate, as well as other related water quality metrics (temperature, dissolved oxygen, pH, and conductivity) in streams of the eastern U.S. We aimed specifically to provide a resource dataset of uniquely high spatial detail for the better understanding of how the rapid appearance or disappearance of this common nutrient at fine scales may relate to other aspects of form and function in these watersheds. To accomplish this, the low-order streams observed in this study extend across environmental gradients in urban and rural land cover, and change from free flowing to impounded water. Study streams were also observed at different levels of steam discharge, both pre and post summer storm events. Four unique 600 m stretches of two low-order creeks in Dutchess County, New York, were observed longitudinally at a fine spatial resolution (20 m). These four 600 m stretches contrasted in land cover from heavily urban channelized streams to mainly rural meandering streams with seasonally active floodplains. Data collection occurred above and below areas where impounded water was input into to the stream via a side tributary to observe the effect of adjacent impoundments, and fine scale water quality was assessed both before and after major storm events to see the influence of wet-period flow path activation on nonpoint source fluxes. Data was organized into a final data table and maps showing how water quality parameters change in regard to land use and land cover, free flowing versus impounded water, and the influence of storm events versus dry periods. Water quality data are also mapped in comparison to thresholds of concern for growth of cyanobacteria - a common constituent of harmful algal blooms in the region. Fine spatial resolution data from this study can be used as a baseline for future studies or modeling efforts at similarly fine scales to better understand why concentrations of nitrate rapidly rise or fall longitudinally at <100 m scales within these forms of streams, and how land cover change and intensified storms due to climate change may further influence water quality dynamics at these uniquely fine scales.

Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?

We present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case. We find that the extrapolated trineutron resonance, as well as the energy for shallow well depths, is lower than the tetraneutron resonance energy. This suggests that a three-neutron resonance exists below a four-neutron resonance in nature and is potentially measurable. To confirm that the relative ordering of three- and four-neutron resonances is not an artifact of the external confinement, we test that the odd-even staggering in the helium isotopic chain is reproduced within this approach. Finally, we discuss similarities between our results and ultracold Fermi gases.

Hydrologic refugia, plants, and climate change.

Climate, physical landscapes, and biota interact to generate heterogeneous hydrologic conditions in space and over time, which are reflected in spatial patterns of species distributions. As these species distributions respond to rapid climate change, microrefugia may support local species persistence in the face of deteriorating climatic suitability. Recent focus on temperature as a determinant of microrefugia insufficiently accounts for the importance of hydrologic processes and changing water availability with changing climate. Where water scarcity is a major limitation now or under future climates, hydrologic microrefugia are likely to prove essential for species persistence, particularly for sessile species and plants. Zones of high relative water availability - mesic microenvironments - are generated by a wide array of hydrologic processes, and may be loosely coupled to climatic processes and therefore buffered from climate change. Here, we review the mechanisms that generate mesic microenvironments and their likely robustness in the face of climate change. We argue that mesic microenvironments will act as species-specific refugia only if the nature and space/time variability in water availability are compatible with the ecological requirements of a target species. We illustrate this argument with case studies drawn from California oak woodland ecosystems. We posit that identification of hydrologic refugia could form a cornerstone of climate-cognizant conservation strategies, but that this would require improved understanding of climate change effects on key hydrologic processes, including frequently cryptic processes such as groundwater flow.

Autologous cord blood transfusion in preterm infants - could its humoral effect be the kez to control prematurity-related complications? A preliminary study.

Umbilical cord blood (UCB), rich in stem/progenitor cells, is partially eliminated from the bloodstream during childbirth because the cord is immediately clamped. We hypothesize that transfusion of autologous UCB to premature infants after delivery could serve as an adjuvant modality for preventing the development of prematurity-related complications. We randomly enrolled 20 preterm infants born before 32 weeks of gestational age (GA), all of whom developed anemia, necessitating transfusion of red blood cells (RBCs). Two groups, matched for GA, were selected: (1) infants (n = 5) who underwent UCB transfusion once within 5 days of birth (mean ± standard deviation, 3.2 ± 1.9 days) and (2) infants (n = 15) from whom UCB was not collected (e.g., lack of consent). The latter served as controls and received allogeneic RBC transfusions (7.8 ± 3.9 days after birth). Selected prematurity-related complications were monitored. Two weeks after UCB/RBC transfusion, peripheral blood samples were collected, and the concentrations of 41 selected growth factors and their receptors were analyzed using a multiplex protein array. UCB transfusions were found to be both feasible and tolerable. Intraventricular haemorrhage was diagnosed in two of five (40%) UCB recipients, but was found in thirteen of fifteen RBC recipients (86.7%). Twenty-two plasma proteins (e.g., insulin-like growth factors, stem cell factor, epidermal growth factors) were found with significantly different concentrations in UCB recipients compared to controls. Results demonstrate safety and feasibility of UCB transfusion in a small group of very premature neonates and should be interpreted as preliminary speculation. Transfusion of UCB could induce a specific humoral effects, and this could serve as an adjuvant modality for prevention of prematurity complications.

Increased circulating endothelial progenitor cells in patients with haemorrhagic and ischaemic stroke: the role of endothelin-1.

Ischaemic stroke induces endothelial progenitor cell (EPC) mobilisation from bone marrow into peripheral blood. Circulating EPCs play an important role in post-injury regeneration of vasculature, whereas endothelial cells (ECs) have been shown to reflect endothelial damage and may be responsible for increased Endothelin-1 (ET-1) expression. We investigated herein the association between numbers of circulating ECs and EPCs, the levels of soluble factors regulating their migration and function, and the clinical outcome in patients with haemorrhagic (HS) or ischaemic stroke (IS). Sixteen patients with HS and eighteen with IS were assessed during the first 24h, day 3, and day 7 after stroke and compared them with twenty-three control subjects. We found elevated EPC and EC concentrations using flow cytometry and increase in VEGF, SDF-1, HGF, and ET-1 plasma levels by ELISA in the HS patients, while ET-1 mRNA expression in peripheral blood cells was elevated in the IS patients. Significant correlations were observed between EPCs or ECs and Big ET-1 protein or mRNA levels in HS but not in the IS patients. We suggest that ET-1 may play a role in pathophysiology of stroke and subsequent EPC mobilisation; however, further studies aimed at the precise elucidation of this issue are required.

Perinatal exposure to lead induces morphological, ultrastructural and molecular alterations in the hippocampus.

The aim of this paper is to examine if pre- and neonatal exposure to lead (Pb) may intensify or inhibit apoptosis or necroptosis in the developing rat brain. Pregnant experimental females received 0.1% lead acetate (PbAc) in drinking water from the first day of gestation until weaning of the offspring; the control group received distilled water. During the feeding of pups, mothers from the experimental group were still receiving PbAc. Pups were weaned at postnatal day 21 and the young rats of both groups then received only distilled water until postnatal day 28. This treatment protocol resulted in a concentration of Pb in rat offspring whole blood (Pb-B) below the threshold of 10 µg/dL, considered safe for humans.We studied Casp-3 activity and expression, AIF nuclear translocation, DNA fragmentation, as well as Bax, Bcl-2 mRNA and protein expression as well as BDNF concentration in selected structures of the rat brain: forebrain cortex (FC), cerebellum (C) and hippocampus (H). The microscopic examinations showed alterations in hippocampal neurons.Our data shows that pre- and neonatal exposure of rats to Pb, leading to Pb-B below 10 µg/dL, can decrease the number of hippocampus neurons, occurring concomitantly with ultrastructural alterations in this region. We observed no morphological or molecular features of severe apoptosis or necrosis (no active Casp-3 and AIF translocation to nucleus) in young brains, despite the reduced levels of BDNF. The potential protective factor against apoptosis was probably the decreased Bax/Bcl-2 ratio, which requires further investigation. Our findings contribute to further understanding of the mechanisms underlying Pb neurotoxicity and cognition impairment in a Pb-exposed developing brain.

Activation of phospholipase A(2) by low levels of fluoride in THP1 macrophages via altered Ca(2+) and cAMP concentration.

Phospholipases (PLA's) participate in the regulation of physiological and pathological processes in the cell, including the release of pro-inflammatory mediators and stimulation of inflammatory processes. It is also well known that fluoride can increase the inflammatory reactions. Therefore we decided to examine the effect of fluorides in concentrations determined in human serum on cPLA(2) and sPLA(2) activity. The incubation of macrophages in fluoride solutions significantly increased the amount of synthesized cellular cAMP, intracellular calcium and sPLA(2) activity in a dose-dependent pattern. The cPLA(2) activity, estimated by the amount of released arachidonic acid, increased significantly when 10 µM NaF was used. The results of our study suggest that fluoride may change the activity of phospholipases in macrophage cells. Probably, increased cAMP concentration activates protein kinase C (PKC) and thus stimulates PLA(2). cAMP also regulates the passage of Ca(2+) through ion channels, which additionally influence PLA(2) throughout Ca(2+)-calmodulin dependent protein kinase.

An epidermal growth factor receptor intron 1 polymorphism in healthy women in Poland.

The frequency of CA allele combinations was assessed in healthy women from Poland and compared to previously published polymorphism data of individuals from Germany and a Caucasian reference group. There were close similarities between these three geographically and ethnically similar populations. By contrast, the distribution of these alleles in European and Asian (Japan) populations proved to be different. There might therefore be major ethnic differences in allelic frequencies of EGFR intron 1 polymorphism. Our results provide new data on EGFR microsatellite instability and may contribute to the understanding of EGFR gene expression regulation. The clinical relevance of these findings warrants further evaluation.

An epidermal growth factor receptor intron 1 polymorphism in healthy women in Poland.

The frequency of CA allele combinations was assessed in healthy women from Poland and compared to previously published polymorphism data of individuals from Germany and a Caucasian reference group. There were close similarities between these three geographically and ethnically similar populations. By contrast, the distribution of these alleles in European and Asian (Japan) populations proved to be different. There might therefore be major ethnic differences in allelic frequencies of EGFR intron 1 polymorphism. Our results provide new data on EGFR microsatellite instability and may contribute to the understanding of EGFR gene expression regulation. The clinical relevance of these findings warrants further evaluation. (Int J Biol Markers 2005; 20: 184-8).