Biomedical subjects
Andrew Clark
Publications and source records attributed to Andrew Clark.
Update of clinical trials from the American College of Cardiology 2003. EPHESUS, SPORTIF-III, ASCOT, COMPANION, UK-PACE and T-wave alternans.
The American College of Cardiology provided much useful new information to inform those who care for patients with heart failure about what they should and should not adopt into current clinical practice. The EPHESUS trial suggests a much wider role for aldosterone antagonists for the management of heart failure and left ventricular systolic dysfunction. SPORTIF-III indicates we may have a safer, simpler warfarin substitute soon. ASCOT reinforces the potential futility of statin therapy unless it is well targeted. The results of the COMPANION study investigating cardiac resynchronisation devices and implantable defibrillators were encouraging but inconclusive and/or hard to interpret. UK-PACE again questions the use of dual chamber pacing. T-wave alternans is an interesting experimental technique that may be useful in selecting which patients need an implantable defibrillator, although the technology needs testing in an appropriate patient population.
Language of self harm is somatic and needs to be learnt.
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Do health changes affect smoking? Evidence from British panel data.
This paper uses seven waves of British Household Panel Survey (BHPS) data to examine the link between health developments while smoking (both one's own and those of other smokers in the same household) and future cigarette consumption. We find those whose health worsens when smoking smoke less in the future, and are more likely to quit. This correlation is consistent with both a Grossman model of health demand (where all parameters are known) and with learning about the health consequences of smoking (where there is uncertainty). There is little effect on smoking from health developments amongst other smokers in the same household. As such, impersonal information provision may have less of an effect on smoking than the delivery of personalised health information, for example through the medical profession.
Vascular recruitment in skeletal muscle during exercise and hyperinsulinemia assessed by contrast ultrasound.
The purpose of this study was to noninvasively quantify the effects of insulin on capillary blood volume (capBV) and RBC velocity (V(RBC)) in skeletal muscle in vivo with the use of contrast-enhanced ultrasound. We performed contrast ultrasound of the rat hindlimb adductor muscles at baseline and after 2-h infusions of either insulin (3 or 40 mU x kg(-1) x min(-1)) or saline. Saline-treated animals were also studied during contractile exercise. V(RBC) and capBV were calculated from the relation between pulsing interval and video intensity. Femoral artery blood flow, measured by a flow probe, increased with both contractile exercise and insulin. Contractile exercise increased capBV more than twofold and V(RBC) fivefold. Insulin also increased capBV more than twofold in a dose-dependent fashion but did not significantly alter V(RBC). Saline infusion did not significantly alter capBV, V(RBC), or femoral artery blood flow. We conclude that physiological changes in skeletal muscle capillary perfusion can be assessed in vivo with the use of contrast-enhanced ultrasound. Exercise increases both V(RBC) and capBV, whereas hyperinsulinemia selectively increases only capBV, which may enhance skeletal muscle glucose uptake.