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A Kelion

Publications and source records attributed to A Kelion.

5 recordsLinked to original sources
PubMed2003

Procedure guidelines for radionuclide myocardial perfusion imaging.

Radionuclide myocardial perfusion imaging (MPI) is an established and non-invasive imaging technique with diagnostic and prognostic efficacy in the investigation of coronary artery disease. It is the only widely available test for assessing myocardial perfusion directly but there are variations in the way it is performed in different centres. Harmonization of practice, at least at a national level, is therefore essential, and clinical governance now makes it mandatory for practice to be based upon evidence whenever possible [ 1]. This is best achieved by expert analysis of the evidence and to this end the British Nuclear Cardiology Society (BNCS) in association with the British Cardiac Society (BCS) and the British Nuclear Medicine Society (BNMS) have developed procedure guidelines for tomographic myocardial perfusion imaging. A systematic literature search was performed and every effort was made to conform with the AGREE recommendations [ 2]. All recommendations are therefore based on either evidence from clinical studies, previous published guidelines or expert consensus of the writing and advisory groups. The guidelines cover the clinical indications of MPI, the methods used for stress testing, the radiopharmaceuticals and the injected activities and also issues related to acquisition, processing and interpretation of images. They do not cover the benefits or drawbacks of the technique in specific circumstances; neither do they address its cost effectiveness in clinical diagnosis and management nor its potential impact on clinical outcomes. The guidelines aim to assist medical practitioners and other health care professionals in recommending, performing, interpreting and reporting single photon emission computed tomography (SPECT) of myocardial perfusion.

Coronary Artery Disease↗
PubMed1989

Electrophysiological evidence for the dendritic localization of a calcium conductance in guinea-pig substantia nigra neurones in vitro.

Within the substantia nigra, anatomical, neurochemical and pharmacological findings strongly suggest that transmitter and protein are secreted from the dendrites of nigrostriatal neurones. This phenomenon may underlie a non classical modulatory cellular mechanism. Two conductances are generated in nigrostriatal neurones independent of somatic action potentials, that might mediate this modulation. However, these conductances have never been directly nor precisely located specifically within the dendrites. The aim of this study was to record the membrane properties of substantia nigra zona compacta neurones in response to selective sectioning of the population of long 'apical' dendrites i.e. the removal of the zona reticulata. Intracellular recordings from substantia nigra zona compacta neurones were made from mesencephalic slices of the guinea-pig brain maintained in vitro. In cells without the apical dendrites, the membrane potential, input resistance and mean firing frequency was not significantly different from the control neurones. However, removal of the substantia nigra zona reticulata virtually abolished one conductance in particular. This conductance, seen in control neurones, is a long lasting slow depolarization which is resistant to tetrodotoxin blockade of sodium channels: rather, it is mediated by the entry of calcium ions and is optimally deinactivated at a hyperpolarised membrane potential. Hence, this study strongly suggests that this conductance is generated exclusively in the 'apical' dendrites. It has been postulated that this long lasting calcium conductance is central to the modulation of nigrostriatal neuronal excitability. Thus, the 'apical' dendrites could play a specific and active role in the functioning of nigrostriatal neurones.

Action Potentials↗