Serotonin reuptake inhibitors and cardiovascular disease

Selective serotonin re-uptake inhibiting drugs (SSRIs) are widely used for endogenous depression. In addition to depleting the nerve terminals of serotonin they also lower blood platelet serotonin levels. Platelet aggregation is a major component of acute coronary syndromes, including sudden death, and also of limb ischaemia. Platelet-released serotonin causes constriction of diseased blood vessels. The recent literature has revealed a number of reports of association between the treatment of depression with SSRIs and reduced events caused by intra-arterial thrombosis. The effects of serotonin and serotonin depletion upon intracoronary thrombosis, diseased blood vessels, blood platelets and bleeding are discussed with recommendations for future research into the potential cardiovascular benefits of SSRIs and serotonin 5HT2A antagonists

Coronary vessel supersensitivity to noradrenaline in the presence of chronic sympathetic denervation.

It is well known that there is usually super-sensitivity to the normal neurotransmitter in chronically denervated organs. The present consensus of opinion is that there is no super-sensitivity of response of myocardial arteriolar resistance vessels to nor-adrenaline after chronic sympathetic denervation; this opinion was tested. We re-analysed the data in the literature on innervated myocardium, plus the effect of chronic sympathetic myocardial denervation induced by surgery plus phenol application. We found that the opinion is based on studies of isolated epicardial arteries. Studies of resistance vessels mostly ignore an important confounding factor, in that myocardial blood flow (MBF) within myocardium is heterogeneous under all circumstances. This heterogeneity is partly related to similar heterogeneity in myocardial oxygen consumption (MVO2), and partly to heterogeneity in local noradrenaline, as assessed by 11C-hydroxyephidrine positron emission tomography. The local volume of distribution of 11C-hydroxyephedrine in innervated myocardium was inversely correlated to local MBF, at the same perfusion pressure, i.e., increasing vasoconstriction with increasing tissue noradrenaline. In chronically denervated myocardium, local MBF was lower for any given amount of noradrenaline, showing the existence of supersensitivity of the resistance vessels. This factor may have a deletereous effect in diabetic patients with cardiac autonomic neuropathy

Phenotypic Variation among Thick-billed Murres from Colonies in Hudson Strait

Thick-billed Murres (Uria lomvia) breeding in the Canadian Arctic are restricted to a small number of colonies, all comprising more that 10,000 pairs. Five of these colonies are scattered through Hudson Strait. We collected adult breeders at three of the colonies - Digges Island, Hantzsch Island, and Akpatok Island - and compared wing and bill measurements and body weights to look for inter-colony differences. Significant inter-colony differences were present for all measurements and a discriminant function analysis showed that some individuals fall completely outside the range of variation for the other colonies. Because of the presence of the Laurentide ice-sheet over Hudson Strait, the present colony sites could not have been occupied for more than 10,000 years. If the observed differences reflect differences in genotype then their evolution must have occurred over this period.Key words: Thick-billed murre, Uria lomvia, phenotypic variation, Hudson Strait, evolutionMots clés: Marmettes de Brunnïch, Uria lomvia, variation des phénotypes, détroit d'Hudson, évolutio

Qualitative study of paramedics' experiences of managing seizures: A national perspective from England

Objectives: The UK ambulance service is expected to now manage more patients in the community and avoid unnecessary transportations to hospital emergency departments (ED). Most people it attends who have experienced seizures have established epilepsy, have experienced uncomplicated seizures and so do not require the full facilities of an ED. Despite this, most are transported there. To understand why, we explored paramedics experiences of managing seizures. Design and setting: Semistructured interviews were conducted with a purposive sample of paramedics from the English ambulance service. Interviews were transcribed and thematically analysed. Participants: A diverse sample of 19 professionals was recruited from 5 different ambulance NHS trusts and the College of Paramedics. Results: Participants confirmed how most seizure patients attended to do not clinically require an ED. They explained, however, that a number of factors influence their care decisions and create a momentum for these patients to still be taken. Of particular importance was the lack of access paramedics have to background medical information on patients. This, and the limited seizure training paramedics receive, meant paramedics often cannot interpret with confidence the normality of a seizure presentation and so transport patients out of precaution. The restricted time paramedics are expected to spend on scene due to the way the ambulance services performance is measured and that are few alternative care pathways which can be used for seizure patients also made conveyance likely. Conclusions: Paramedics are working within a system that does not currently facilitate nonconveyance of seizure patients. Organisational, structural, professional and educational factors impact care decisions and means transportation to ED remains the default option. Improving paramedics access to medical histories, their seizure management training and developing performance measures for the service that incentivise care that is cost-effective for all of the health service might reduce unnecessary conveyances to ED

Speleothem U-series constraints on scarp retreat rates and landscape evolution: an example from the Severn valley and Cotswold Hills gull-caves, UK

Modelling landscape evolution requires quantitative estimates of erosional processes. Dating erosional landscape features such as escarpments is usually difficult because of the lack of datable deposits. Some escarpments and valley margins are associated with the formation of mass-movement caves, sometimes known as ‘gull’ or ‘crevice’ caves, which are typically restricted to within 0.5 km of the valley margin or scarp edge. As in other caves, these mass-movement cavities may host speleothems. As gull-caves develop only after valley incision, uranium-series dating of speleothems within them can provide a minimum age for the timing of valley excavation and scarp formation. Here we present data from several gull-caves in the Cotswold Hills, which form the eastern flank of the Severn valley in southern England. U-series ages from these gull-caves yield estimates for both the minimum age of the Cotswold escarpment and the maximum scarp retreat rate. This is combined with data from geological modelling to propose a model for the evolution of the Severn valley and the Cotswold Hills. The data suggest that the location of the escarpment and regional topography is determined not by valley widening and scarp retreat, but by the in situ generation of relief by differential erosion

'Seizure First Aid Training' for people with epilepsy who attend emergency departments, and their family and friends: study protocol for intervention development and a pilot randomised controlled trial.

INTRODUCTION: People with chronic epilepsy (PWE) often make costly but clinically unnecessary emergency department (ED) visits. Offering them and their carers a self-management intervention that improves confidence and ability to manage seizures may lead to fewer visits. As no such intervention currently exists, we describe a project to develop and pilot one. METHODS AND ANALYSIS: To develop the intervention, an existing group-based seizure management course that has been offered by the Epilepsy Society within the voluntary sector to a broader audience will be adapted. Feedback from PWE, carers and representatives from the main groups caring for PWE will help refine the course so that it addresses the needs of ED attendees. Its behaviour change potential will also be optimised. A pilot randomised controlled trial will then be completed. 80 PWE aged ≥16 who have visited the ED in the prior 12 months on ≥2 occasions, along with one of their family members or friends, will be recruited from three NHS EDs. Dyads will be randomised to receive the intervention or treatment as usual alone. The proposed primary outcome is ED use in the 12 months following randomisation. For the pilot, this will be measured using routine hospital data. Secondary outcomes will be measured by patients and carers completing questionnaires 3, 6 and 12 months postrandomisation. Rates of recruitment, retention and unblinding will be calculated, along with the ED event rate in the control group and an estimate of the intervention's effect on the outcome measures. ETHICS AND DISSEMINATION: Ethical approval: NRES Committee North West-Liverpool East (Reference number 15/NW/0225). The project's findings will provide robust evidence on the acceptability of seizure management training and on the optimal design of a future definitive trial. The findings will be published in peer-reviewed journals and presented at conferences. TRIAL REGISTRATION NUMBER: ISRCTN13 871 327

Status of the PICASSO Project

The Picasso project is a dark matter search experiment based on the superheated droplet technique. Preliminary runs performed at the Picasso Lab in Montreal have showed the suitability of this detection technique to the search for weakly interacting cold dark matter particles. In July 2002, a new phase of the project started. A batch of six 1-liter detectors with an active mass of approximately 40g was installed in a gallery of the SNO observatory in Sudbury, Ontario, Canada at a depth of 6,800 feet (2,070m). We give a status report on the new experimental setup, data analysis, and preliminary limits on spin-dependent neutralino interaction cross section.Comment: 3 pages, 2 figures. To appear in the Proceedings of the TAUP 2003 conference, 5-9 September, 2003, University of Washington, Seattle, US

High sensitivity measurement of 224Ra and 226Ra in water with an improved hydrous titanium oxide technique at the Sudbury Neutrino Observatory

The existing hydrous titanium oxide (HTiO) technique for the measurement of 224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been changed to make it faster and less sensitive to trace impurities in the HTiO eluate. Using HTiO-loaded filters followed by cation exchange adsorption and HTiO co-precipitation, Ra isotopes from 200-450 tonnes of heavy water can be extracted and concentrated into a single sample of a few millilitres with a total chemical efficiency of 50%. Combined with beta-alpha coincidence counting, this method is capable of measuring 2.0x10^3 uBq/kg of 224Ra and 3.7x10^3 uBq/kg of 226Ra from the 232Th and 238U decay chains, respectively, for a 275 tonne D2O assay, which are equivalent to 5x10^16 g Th/g and 3x10^16 g U/g in heavy water.Comment: 8 Pages, 2 figures and 2 table

Nonintegrable Interaction of Ion-Acoustic and Electromagnetic Waves in a Plasma

In this paper we re-examine the one-dimensional interaction of electromagnetic and ion acoustic waves in a plasma. Our model is similar to one solved by Rao et al. (Phys. Fluids, vol. 26, 2488 (1983)) under a number of analytical approximations. Here we perform a numerical investigation to examine the stability of the model. We find that for slightly over dense plasmas, the propagation of stable solitary modes can occur in an adiabatic regime where the ion acoustic electric field potential is enslaved to the electromagnetic field of a laser. But if the laser intensity or plasma density increases or the laser frequency decreases, the adiabatic regime loses stability via a transition to chaos. New asymptotic states are attained when the adiabatic regime no longer exists. In these new states, the plasma becomes rarefied, and the laser field tends to behave like a vacuum field.Comment: 19 pages, REVTeX, 6 ps figures, accepted for publication in Phys. Rev.

Irreducibility of the Tutte polynomial of an embedded graph

We prove that the ribbon graph polynomial of a graph embedded in an orientable surface is irreducible if and only if the embedded graph is neither the disjoint union nor the join of embedded graphs. This result is analogous to the fact that the Tutte polynomial of a graph is irreducible if and only if the graph is connected and non-separable