12 research outputs found
The large grey area between âbona fideâ and ârogueâ stem cell interventions â ethical acceptability and the need to include local variability
This article aims to put into perspective the binary opposition between âscientificâ clinical research trials and ârogueâ experimental stem cell therapies, and to show why the ethics criteria used by the dominant science community are not suitable for distinguishing between adequate and inadequate treatments. By focusing on the grey area between clinical stem cell trials and stem cell experimentation, the experimental space where patients, medical professionals and life scientists negotiate for diverging reasons and aims, I show why idealised notions of ethics are not feasible for many stem cell scientists in low- and middle-income countries.
Drawing on fieldwork in China from 2012 to 2013, the article asks why âthe unethicalâ according to some is acceptable to Chinese life scientists. The case study of stem cell service provider Beike Biotech illustrates how stem cell interventions take place in a large grey area, where narrow notions of ethics are blurred with and supplanted by broader notions of ethics, co-determined by estimations of socio-economic, political and cultural understandings of risk, opportunity and benefit.
I borrow the term âbionetworkingâ, understood as the entrepreneurial aspects of scientific networks that engage in creating biomedical products, to analyse various forms of medical experimentation. I speak of the âexternalisationâ and âinternalisationâ of local factors to elucidate how features of patient populations and their environments are subsumed in clinical research applications. Compared to polarised views of stem cell therapy, this approach increases the transparency of clinical interventions and broadens our understanding of why âstem cell tourismâ to some is âstem cell therapyâ to others
Moving out of the laboratory: does nicotine improve everyday attention?
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Echocardiography to magnetic resonance image registration for use in image-guide electrophysiology procedures
We present a novel method to register three-dimensional echocardiography (echo) images with magnetic resonance images (MRI) based on anatomical features, which could be used in the registration pipeline for overlaying MRI-derived roadmaps onto two-dimensional live X-ray images in electrophysiology (EP) procedures. The features used in image registration are the surface of the left ventricle and a manually defined centerline of the descending aorta. The MR-derived surface is generated using a fully automated algorithm, and the echo-derived surface is produced using a semi-automatic process. We test our method on six volunteers and three patients. We validated registration accuracy using two methods. The first calculated a root mean square distance error using anatomical landmarks. The second method used catheters as landmarks in one clinical EP procedure. Results show a mean error of 4.24 mm, which is acceptable for our clinical application, and no failed registrations were observed. In addition, our algorithm works on clinical data, is fast and only requires a small amount of manual input, and so it is applicable to use during EP procedures
Self-perception levels of mothers dealing with infant care problems for babies 0-12 months old
Space-variant simultaneous detection of several objects by the use of multiple anamorphic fractional-Fourier-transform filters
Zur Frage der Ăbertragung mykoplasmaĂ€hnlicher Organismen durch das Saatgut infizierter Pflanzen
The bee venom peptide tertiapin underlines the role of I(KACh) in acetylcholine-induced atrioventricular blocks
1. Acetylcholine (ACh) is an important neuromodulator of cardiac function that is released upon stimulation of the vagus nerve. Despite numerous reports on activation of I(KACh) by acetylcholine in cardiomyocytes, it has yet to be demonstrated what role this channel plays in cardiac conduction. We studied the effect of tertiapin, a bee venom peptide blocking I(KACh), to evaluate the role of I(KACh) in Langendorff preparations challenged with ACh. 2. ACh (0.5âÎŒM) reproducibly and reversibly induced complete atrioventricular (AV) blocks in retroperfused guinea-pig isolated hearts (n=12). 3. Tertiapin (10 to 300ânM) dose-dependently and reversibly prevented the AV conduction decrements and the complete blocks in unpaced hearts (n=8, P<0.01). 4. Tertiapin dose-dependently blunted the ACh-induced negative chronotropic response from an ACh-induced decrease in heart rate of 39±16% in control conditions to 3±3% after 300ânM tertiapin (P=0.01). These effects were not accompanied by any significant change in QT intervals. 5. Tertiapin blocked I(KACh) with an IC(50) of 30±4ânM with no significant effect on the major currents classically associated with cardiac repolarisation process (I(Kr), I(Ks), I(to1), I(sus), I(K1) or I(KATP)) or AV conduction (I(Na) and I(Ca(L))). 6. In summary, tertiapin prevents dose-dependently ACh-induced AV blocks in mammalian hearts by inhibiting I(KACh)