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21.
This paper is the third and final part of a series of articles reviewing mathematical and computer models of the electrophysiological processes. This section reviews the arrhythmia simulation and discusses models of arrhythmogenic processes, fibrillation and defibrillation, and of heart-pacemaker interaction. The models of arrhythmogenesis are classified into three main sections: models of reentry and vortex reentry, models of myocardial electrotonic interactions, and models of macroreentrant supraventricular tachycardias. This final part of the review discusses the future potential of mathematical and computer models of different cardiac processes. 相似文献
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MARK J. CASTELLANET M.D. JUAN GARZA M.D. STANLEY P. SHANER P.E. JOHN C. MESSENGER M.D. 《Journal of cardiovascular electrophysiology》1987,1(5):360-375
Telemetry of programmed and measured data is an important feature of many pacemakers currently used in clinical practice. The ability to receive non-invasive data from the implanted device constitutes a major advantage for the long-term follow-up of the patients and of device performance. There are numerous types of data retrievable via telemetry: parameters of device characteristics (output, battery longevity, impedance, etc), event recorders or counters, event markers, and endocardial electrograms. Ideally, this information should be beneficial in the longitudinal surveilance of modern pacemakers. 相似文献
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The Effect of 50 Hz External Electrical Interference on Implanted Cardiac Pacemakers 总被引:2,自引:0,他引:2
GERALD C. KAYE GHAZWAN S. BUTROUS ALI ALLEN STUART J. MELDRUM JOHN G. MALE † A. JOHN CAMM 《Pacing and clinical electrophysiology : PACE》1988,11(7):999-1008
The effects of injected 50 Hz alternating current on the function of cardiac pacemakers has been observed in 18 patients with implanted unipolar VVI units. Current, in the range 0-600 microA was applied via electrodes attached to the patients' upper body and feet and fed from a specially designed current injection unit at the bedside. Most implanted pacemakers reverted to interference mode in the current range 29-250 microA. At current levels just below the reversion current all units developed irregular and inappropriate pacing. This current level was pacemaker dependent and varied in the range 27-246 microA. The total reversion current depended on the location of the injecting electrodes and on the patients' posture. The sensitivity of the units to injected interference was increased by deep inspiration. Temporary pacing catheters fitted to an additional ten patients were used to monitor the interference voltage which would be sensed by an implanted unit. This voltage was similarly dependent on patient posture and on deep respiration. Current injection has proved to be a safe, controllable and reproducible method of testing the sensitivity of implanted pacemakers to 50 Hz external interference. 相似文献
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A survey was conducted to ascertain general medical practitioners' (GPs') attitudes to community pharmacists' use of patient medication records (PMRs) and to assess whether GPs envisage a role for family health service authorities (FHSAs) in maintaining records of patients' data. The survey questionnaire was sent by post to all 1,257 GPs in contract with Avon and Devon FHSAs. A total of 811 questionnaires was returned, an overall response rate of 64.5 per cent. A majority (59 per cent) of GPs considered that community pharmacists should keep patient medication records and there was strong support for pharmacists holding PMRs for the elderly and confused, and also for patients with diabetes, asthma, epilepsy, and those patients who had experienced major adverse drug reactions or allergies. Some GPs, however, remained unconvinced of the usefulness of a pharmacy PMR. Seventy four per cent of respondents considered that patients should keep their own medication records. In contrast, only 4 per cent were in agreement with patient medication data being stored by FHSAs. The community pharmacist's role in maintaining PMRs received less support from doctors in dispensing practices than from their non-dispensing counterparts. Some 80 per cent of respondents were in favour of pharmacists providing PMR system-generated patient information leaflets with dispensed medicines. Most GPs considered that such leaflets had a positive effect on patient compliance. Recently registered GPs were found to be more supportive than their older colleagues of community pharmacists recording patients' clinical conditions and providing information leaflets. 相似文献
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SESHA NATARAJAN STEPHEN M. FESTIN ANDERS HEDBERG EDDIE C.-K. LIU DAVID M. FLOYD JOHN T. HUNT 《Chemical biology & drug design》1992,40(6):567-574
We have developed an expeditious method for the incorporation of the biotinylaminocaproyl moiety on the ε-amino group of a lysine residue within a peptide chain in a site-specific manner. Using t-Boc chemistry for the solid phase synthesis approach and a base labile, acid stable protecting group (Fmoc-) for the ε-amino group of the target lysine, we prepared fully protected resin bound peptides which are site-specifically biotinylated. Following HF cleavage, the uniquely biotinylated peptides were obtained in a high degree of purity. Using this approach, a number of biotinylaminocaproyllysyl derivatives of a monocyclic Endothelin-1 analog were prepared. Synthesis of selected bicyclic analogs of high affinity monocycles led to the preparation of the bicyclic [Nle7]ET-1 analog containing ε-biotinylaminocaproyllysine at position-9. This peptide, with Kd= 0.08 nM, has 1000-fold higher affinity for the ETA receptor than the commercially available Nα-biotinylated Endothelin-1. The general utility of this biotinylation methodology was demonstrated by the synthesis of a site-specifically biotinylated PTH analog which contained several side chain functionalized amino acid residues in its sequence. The synthetic method reported here is convergent in that it allows the facile variation of the length of the spacer and also offers the potential to introduce in a site specific manner other groups such as affinity labels and fluorescent tags. 相似文献