Role of transport performance on neuron cell morphology

The compartmental model is a basic tool for studying signal propagation in neurons, and, if the model parameters are adequately defined, it can also be of help in the study of electrical or fluid transport. Here we show that the input resistance, in different networks which simulate the passive properties of neurons, is the result of an interplay between the relevant conductances, morphology and size. These results suggest that neurons must grow in such a way that facilitates the current flow. We propose that power consumption is an important factor by which neurons attain their final morphological appearance.Comment: 9 pages with 3 figures, submitted to Neuroscience Letter

Nitrate contamination of drinking water: relationship with HPRT variant frequency in lymphocyte DNA and urinary excretion of N-nitrosamines.

We studied peripheral lymphocyte HPRT variant frequency and endogenous nitrosation in human populations exposed to various nitrate levels in their drinking water. Four test populations of women volunteers were compared. Low and medium tap water nitrate exposure groups (14 and 21 subjects) were using public water supplies with nitrate levels of 0.02 and 17.5 mg/l, respectively. Medium and high well water nitrate exposure groups (6 and 9 subjects) were using private water wells with mean nitrate levels of 25 and 135 mg/l, respectively. Higher nitrate intake by drinking water consumption resulted in a dose-dependent increase in 24-hr urinary nitrate excretion and in increased salivary nitrate and nitrite levels. The mean log variant frequency of peripheral lymphocytes was significantly higher in the medium well water exposure group than in the low and medium tap water exposure groups. An inverse correlation between peripheral lymphocyte labeling index and nitrate concentration of drinking water was observed. Analysis of N-nitrosamine in the urine of 22 subjects by gas chromatography-mass spectrometry revealed the presence of N-nitrosopyrrolidine in 18 subjects. Analysis of the mutagenicity of well water samples showed that a small number of the well water samples were mutagenic in the Ames Salmonella typhimurium test after concentration over XAD-2 resin. In conclusion, consumption of drinking water, especially well water, with high nitrate levels can imply a genotoxic risk for humans as indicated by increased HPRT variant frequencies and by endogenous formation of carcinogenic N-nitroso compounds from nitrate-derived nitrite

Proteome-based plasma biomarkers for Alzheimer's disease

Alzheimer's disease is a common and devastating disease for which there is no readily available biomarker to aid diagnosis or to monitor disease progression. Biomarkers have been sought in CSF but no previous study has used two-dimensional gel electrophoresis coupled with mass spectrometry to seek biomarkers in peripheral tissue. We performed a case-control study of plasma using this proteomics approach to identify proteins that differ in the disease state relative to aged controls. For discovery-phase proteomics analysis, 50 people with Alzheimer's dementia were recruited through secondary services and 50 normal elderly controls through primary care. For validation purposes a total of 511 subjects with Alzheimer's disease and other neurodegenerative diseases and normal elderly controls were examined. Image analysis of the protein distribution of the gels alone identifies disease cases with 56% sensitivity and 80% specificity. Mass spectrometric analysis of the changes observed in two-dimensional electrophoresis identified a number of proteins previously implicated in the disease pathology, including complement factor H (CFH) precursor and α-2-macroglobulin (α- 2M). Using semi-quantitative immunoblotting, the elevation of CFH and α- 2M was shown to be specific for Alzheimer's disease and to correlate with disease severity although alternative assays would be necessary to improve sensitivity and specificity. These findings suggest that blood may be a rich source for biomarkers of Alzheimer's disease and that CFH, together with other proteins such as α- 2M may be a specific markers of this illness. © 2006 The Author(s).link_to_subscribed_fulltex

Queen Elizabeth’s Leadership Abroad: The Netherlands in the 1570s

In 1576, after Edmund Grindal, archbishop of Canterbury, presumed to lecture Queen Elizabeth on the importance of preaching and on her duty to listen to such lectures, his influence diminished precipitously, and leadership of the established English church fell to Bishop Aylmer. Grindal’s friends on the queen’s Privy Council, “forward” Calvinists (or ultra-Protestants), were powerless to save him from the consequences of his indiscretion, which damaged the ultras’ other initiatives’ chances of success. This paper concerns one of those initiatives. From the late 1560s, they urged their queen “actively” to intervene in the Dutch wars. They collaborated with Calvinists on the Continent who befriended Prince William of Orange and who hoped to help him hold together a coalition of religiously reformed and Roman Catholic insurgents in the seventeen provinces of the Low Countries. The English ultra-Protestants would have their government send money, munitions, and men in arms to the Netherlands, to tip the balance against viceroys sent by King Philip II of Spain. Grindal’s setback undermined the English Calvinists’ efforts to form an Anglo-Dutch alliance which, they assumed, would boost the prospects for an international Protestant league. Yet Elizabeth did assist the Dutch as they wrestled with decisions forced on them by developments in the Netherlands during the 1570s, and she did so more consistently and more cleverly than many historians of Tudor diplomacy have thought. Two competing assessments determine the way questions are formulated in the study of the queen’s and regime’s Dutch diplomacy. The general consensus is that she was indecisive and inconsistent. Paul Hammer characterizes Elizabeth’s responses to the crises in the Low Countries as a “zigzag of different” (“even contradictory”) maneuvers. Wallace McCaffrey and R. B. Wernham agree that England’s “hesitations and gyrations” do not pass as coherent, creditable policy. Charles Wilson scolds Elizabeth for being timid and tepid--incapable of enthusiasm for “a great cause.” But David J.B. Trim’s striking counterthrust depicts the queen’s overtures to Netherlanders as part of her courageous – and “confessionally driven” – foreign policy; Trim replaces “hesitation” and “zigzag” with a coherent “Protestant programme of action prioritized by the Elizabethan government” with the aim of improving prospects for “Calvinist internationalism.” What follows is an alternative to all these characterizations, one that, as noted, finds evidence for greater consistency and coherence in Elizabeth’s leadership and less confessional “drive.” That she would have been uneasy around religious extremists ought not to astonish us; her father’s, step-brother’s, and step-sister’s reigns as well as the start of her own were disturbed by zealous subjects, who were bent on shoring up or dismantling the realm’s religious settlements

Crystal structure of dichlorido(4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane)iron(III) hexafluoridophosphate

The title compound, [FeCl₂(C₁₄H₃₀N₄)]PF₆, contains Fe³⁺ coordinated by the four nitro­gen atoms of an ethyl­ene cross-bridged cyclam macrocycle and two cis chloride ligands in a distorted octa­hedral environment. In contrast to other similar compounds this is a monomer. Inter­molecular C-H...Cl inter­actions exist in the structure between the complex ions. Comparison with the mononuclear Fe²⁺ complex of the same ligand shows that the smaller Fe³⁺ ion is more fully engulfed by the cavity of the bicyclic ligand. Comparison with the μ-oxido dinuclear complex of an unsubstituted ligand of the same size demonstrates that the methyl groups of 4,11-dimethyl-1,4,8,11-tetra­aza­bicyclo­[6.6.2]hexa­decane prevent dimerization upon oxidation

Outpatient follow-up after mild traumatic brain injury:Results of the UPFRONT-study

Objective: To investigate outpatient follow-up after mild traumatic brain injury (mTBI) by various medical specialists, for both hospitalized and non-hospitalized patients, and to study guideline adherence regarding hospital admission. Methods: Patients (n = 1151) with mTBI recruited from the emergency department received questionnaires 2 weeks (n = 879), 3 months (n = 780) and 6 months (n = 668) after injury comprising outpatient follow-up by various health care providers, and outcome defined by the Glasgow Outcome Scale Extended (GOS-E) after 6 months. Results: Hospitalized patients (60%) were older (46.6 ± 19.9 vs. 40.6 ± 18.5 years), more severely injured (GCS <15, 50% vs. 13%) with more Computed Tomography (CT) abnormalities on admission (21% vs. 2%) compared to non-hospitalized patients (p < 0.01) . Almost half of the patients visited a neurologist at the outpatient clinic within six months (60% of the hospitalized and 25% of the non-hospitalized patients (χ2 = 67.10, p < 0.01)), and approximately ten per cent consulted a psychiatrist/psychologist. Outcome was unfavourable (GOS-E <7) in 34% of hospitalized and 21% of non-hospitalized patients (χ2 = 11.89, p < 0.01). Conclusion: Two-thirds of all mTBI patients consult one or more specialists within six months after injury, with 30% having an unfavourable outcome. A quarter of non-hospitalized patients was seen at the outpatient neurology clinic, underling the importance of regular follow-up of mTBI patients irrespective of hospital admittance

Simplivariate Models: Uncovering the Underlying Biology in Functional Genomics Data

One of the first steps in analyzing high-dimensional functional genomics data is an exploratory analysis of such data. Cluster Analysis and Principal Component Analysis are then usually the method of choice. Despite their versatility they also have a severe drawback: they do not always generate simple and interpretable solutions. On the basis of the observation that functional genomics data often contain both informative and non-informative variation, we propose a method that finds sets of variables containing informative variation. This informative variation is subsequently expressed in easily interpretable simplivariate components

Visualizing the Anthropocene dialectically: Jessica Woodworth and Peter Brosens’ eco-crisis trilogy

The ambition of this article is to propose a way of visualizing the Anthropocene dialectically. As suggested by the Dutch atmospheric chemist Paul Crutzen and the professor of biology Eugene F. Stoermer, the term Anthropocene refers to a historical period in which humankind has turned into a geological force that transforms the natural environment in such a way that it is hard to distinguish between the human and the natural world. Crutzen and Stoermer explain that the Anthropocene has begun after the Holocene, the geological epoch that followed the last ice age and lasted until the industrial revolution. Drawing on a number of figures such as the “tenfold” increase in urbanisation, the extreme transformation of land surface by human action, the use of more than 50% of all accessible fresh water by humans, and the massive increase in greenhouse emissions, Crutzen and Stoermer conclude that the term Anthropocene describes aptly mankind's influence on ecological and geological cycles (Crutzen & Stoermer, 2000, p.17). The wager of this article is that we need to identify ways to visualize the Anthropocene dialectically and I proceed to do so using as a case study Jessica Woodworth's and Peter Brosen's trilogy on the conflict between humans and nature, which consists of Khadak (2006), Altiplano (2009), and The Fifth Season (La Cinquième Saison, 2012)