Post-haemorrhagic anaemia in sea bass, Dicentrarchus labrax (L.), caused by blood feeding of Ceratothoa oestroides (Isopoda: Cymothoidae)

The effects of the fish parasitic isopod, Ceratothoa oestroides (Risso), on haematological parameters of its cage-cultured sea bass host, Dicentrarchus labrax (L.), were studied. Analyses of blood parameters (cell counts, haemoglobin content and haematocrit) were carried out on parasitized and unparasitized sea bass from a fish farm in Turkey. Parasitized fish had significantly lowered erythrocyte counts, haematocrit and haemoglobin values and significantly increased leucocyte counts. Blood feeding by C. oestroides thus produces a post-haemorrhagic anaemia and the fish appear to mount an immune response to the presence of parasites.

Functionalised amyloid fibrils for roles in cell adhesion

We describe experiments designed to explore the possibility of using amyloid fibrils as new nanoscale biomaterials for promoting and exploiting cell adhesion, migration and differentiation in vitro. We created peptides that add the biological cell adhesion sequence (RGD) or a control sequence (RAD) to the C-terminus of an 11-residue peptide corresponding to residues 105-115 of the amyloidogenic protein transthyretin. These peptides readily self-assemble in aqueous solution to form amyloid fibrils, and X-ray fibre diffraction shows that they possess the same strand and sheet spacing in the characteristic cross-beta structure as do fibrils formed by the parent peptide. We report that the fibrils containing the RGD sequence are bioactive and that these fibrils interact specifically with cells via the RGD group displayed on the fibril surface. As the design of such functionalized fibrils can be systematically altered, these findings suggest that it will be possible to generate nanomaterials based on amyloid fibrils that are tailored to promote interactions with a wide variety of cell types. (c) 2007 Elsevier Ltd. All rights reserved.

Population based models of cortical drug response: insights from anaesthesia

A great explanatory gap lies between the molecular pharmacology of psychoactive agents and the neurophysiological changes they induce, as recorded by neuroimaging modalities. Causally relating the cellular actions of psychoactive compounds to their influence on population activity is experimentally challenging. Recent developments in the dynamical modelling of neural tissue have attempted to span this explanatory gap between microscopic targets and their macroscopic neurophysiological effects via a range of biologically plausible dynamical models of cortical tissue. Such theoretical models allow exploration of neural dynamics, in particular their modification by drug action. The ability to theoretically bridge scales is due to a biologically plausible averaging of cortical tissue properties. In the resulting macroscopic neural field, individual neurons need not be explicitly represented (as in neural networks). The following paper aims to provide a non-technical introduction to the mean field population modelling of drug action and its recent successes in modelling anaesthesia.

Understanding the effects of anesthetic agents on the EEG through neural field theory

Anesthetic and analgesic agents act through a diverse range of pharmacological mechanisms. Existing empirical data clearly shows that such "microscopic" pharmacological diversity is reflected in their "macroscopic" effects on the human electroencephalogram (EEG). Based on a detailed mesoscopic neural field model we theoretically posit that anesthetic induced EEG activity is due to selective parametric changes in synaptic efficacy and dynamics. Specifically, on the basis of physiologically constrained modeling, it is speculated that the selective modification of inhibitory or excitatory synaptic activity may differentially effect the EEG spectrum. Such results emphasize the importance of neural field theories of brain electrical activity for elucidating the principles whereby pharmacological agents effect the EEG. Such insights will contribute to improved methods for monitoring depth of anesthesia using the EEG.

Early treatment with intranasal neostigmine reduces mortality in a mouse model of Naja naja (Indian Cobra) envenomation

Objective. Most snakebite deaths occur prior to hospital arrival; yet inexpensive, effective, and easy to administer out-of-hospital treatments do not exist. Acetylcholinesterase inhibitors can be therapeutic in neurotoxic envenomations when administered intravenously, but nasally delivered drugs could facilitate prehospital therapy for these patients. We tested the feasibility of this idea in experimentally envenomed mice. Methods. Mice received intraperitoneal injections of Naja naja venom 2.5 to 10 times the estimated LD50 and then received 5

The timing and causes of the Neolithic elm decline: new evidence from the Lower Thames Valley (London, UK)

Two new multi-proxy records of environmental change are provided from Horton Kirby Paper Mill and Old Seager Distillery in the Lower Thames Valley. Each site has evidence for a decline in elm woodland, which at Horton Kirby Paper Mill is recorded earlier than any other published record from the British Isles: sometime between 7320 and 7240 cal BP. Scolytus scolytus/S. multistriatus (the vectors for Dutch elm disease) are recorded after the decline in both sequences, adding to the number of sites with such evidence in the British Isles. Evidence of paludification and human activity are also recorded at the time of the elm decline reinforcing the multi-causal hypothesis. Integration of these results with 21 palaeoenvironmental records has produced a large number of well-dated, multiproxy records of the elm decline in this part of the UK. On the basis of this dataset, a classification system for categorising the relationships between the causal factors of the elm decline is proposed and recommended for future studies.

Adsorption of organic molecules at the TiO2(110) surface: the effect of van der Waals interactions

Understanding the interaction of organic molecules with TiO2 surfaces is important for a wide range of technological applications. While density functional theory (DFT) calculations can provide valuable insight about these interactions, traditional DFT approaches with local exchange-correlation functionals suffer from a poor description of non-bonding van der Waals (vdW) interactions. We examine here the contribution of vdW forces to the interaction of small organic molecules (methane, methanol, formic acid and glycine) with the TiO2 (110) surface, based on DFT calculations with the optB88-vdW functional. The adsorption geometries and energies at different configurations were also obtained in the standard generalized gradient approximation (GGA-PBE) for comparison. We find that the optB88-vdW consistently gives shorter surface adsorbate-to-surface distances and slightly stronger interactions than PBE for the weak (physisorbed) modes of adsorption. In the case of strongly adsorbed (chemisorbed) molecules both functionals give similar results for the adsorption geometries, and also similar values of the relative energies between different chemisorption modes for each molecule. In particular both functionals predict that dissociative adsorption is more favourable than molecular adsorption for methanol, formic acid and glycine, in general agreement with experiment. The dissociation energies obtained from both functionals are also very similar, indicating that vdW interactions do not affect the thermodynamics of surface deprotonation. However, the optB88-vdW always predicts stronger adsorption than PBE. The comparison of the methanol adsorption energies with values obtained from a Redhead analysis of temperature programmed desorption data suggests that optB88-vdW significantly overestimates the adsorption strength, although we warn about the uncertainties involved in such comparisons.

A review of biochars’ potential role in the remediation, revegetation and restoration of contaminated soils

Biochars are biological residues combusted under low oxygen conditions, resulting in a porous, low density carbon rich material. Their large surface areas and cation exchange capacities, determined to a large extent by source materials and pyrolysis temperatures, enables enhanced sorption of both organic and inorganic contaminants to their surfaces, reducing pollutant mobility when amending contaminated soils. Liming effects or release of carbon into soil solution may increase arsenic mobility, whilst low capital but enhanced retention of plant nutrients can restrict revegetation on degraded soils amended only with biochars; the combination of composts, manures and other amendments with biochars could be their most effective deployment to soils requiring stabilisation by revegetation. Specific mechanisms of contaminant-biochar retention and release over time and the environmental impact of biochar amendments on soil organisms remain somewhat unclear but must be investigated to ensure that the management of environmental pollution coincides with ecological sustainability.

Rainfastness of poly(vinyl alcohol) deposits on Vicia faba leaf surfaces: from laboratory-scale washing to simulated rain

Rainfastness is the ability of agrochemical deposits to resist wash-off by rain and other related environmental phenomena. This work reports laboratory-scale and raintower studies of the rainfastness of fluorescently labeled poly(vinyl alcohol) (PVA) using fluorescent microscopy combined with image analysis. Samples of hydrolyzed PVA exhibit improved rainfastness over a threshold molecular weight, which correlates with PVA film dissolution, swelling, and crystalline properties. It was also established that the rainfastness of PVA scaled with the molecular weight over this threshold. These PVA samples were further characterized in order to determine the effect of the crystallinity on rainfastness. The quantification of rainfastness is of great interest to the field of agrochemical formulation development in order to improve the efficacy of pesticides and their adjuvants.