THE EFFECT OF GLYCEROL ON THE PERCUTANEOUS ABSORPTION OF METHYL NICOTINATE

Summary.— The effect of glycerol on the rate of percutaneous absorption of methyl nicotinate from aqueous vehicles was investigated. The partition coefficients of methyl nicotinate between isopropyl myristate and aqueous solutions of glycerol were determined. The diffusivity of methyl nicotinate in various aqueous solutions of glycerol was also studied. It was shown that addition of glycerol in concentrations above 60% delayed the onset of erythema in human skin. The results suggest that this effect is related to the partition coefficient and diffusivity of methyl nicotinate in the aqueous vehicle. The osmotic effects of glycerol are negligible.     

Exposure to passive smoking among bar staff

The median saliva cotinine concentration in 42 non-smoking bar staff in central London and Birmingham was 7.95 ng/ml, indicating a nicotine intake of about 0.6 mg per day. Pubs appear to give rise to exceptionally heavy exposure to environmental tobacco smoke. Passive smoking in pubs is of concern for its impact both on customers and on those for whom the pub is a place of work.     

Renal Denervation for Treatment of Cardiac Arrhythmias: State of the Art and Future Directions

Renal Denervation for Treatment of Cardiac Arrhythmias . It has now been more than a quarter of a century since modulation of the sympathetic nervous system was proposed for the treatment of cardiac arrhythmias of different origins. But it has also been some time since some of the early surgical attempts have been abandoned. With the development of ablation techniques, however, new approaches and targets have been recently introduced that have revolutionized our way of thinking about sympathetic modulation. Renal nerve ablation technology is now being successfully used for the treatment of resistant hypertension, but the indication spectrum might broaden and new therapeutic options might arise in the near future. This review focuses on the possible impact of renal sympathetic system modulation on cardiac arrhythmias, the current evidence supporting this approach, and the ongoing trials of this method in electrophysiological laboratories. We will discuss the potential roles that sympathetic modulation may play in the future.     

Modelling the macrophage invasion of tumours: Effects on growth and composition

E-mail: owen{at}maths.warwick.ac.uk E-mail: jas{at}maths.warwick.ac.uk Even in the early stages of their development, tumours are notsimply a homogeneous grouping of mutant cells; rather, theydevelop in tandem with normal tissue cells, and also recruitother cell types including lymphatic cells and the endothelialcells required for the development of a blood supply. It hasbeen repeatedly seen that macrophages form a significant proportionof the tumour mass, and that they can have a variety of effectsupon the tumour, leading to a delicate balance between growthpromotion and inhibition. This paper develops a model for theearly, avascular growth of a tumour, concentrating on the inhibitoryeffect of macrophages due to their cytolytic activity. It isshown that such an immune response is not sufficient to preventgrowth, due to it being a second-order process with respectto the density of the tumour cells present However, the presenceof macrophages does have important effects on the tumour composition,and the authors perform a detailed bifurcation analysis of theirmodel to clarify this. An extended model is also consideredwhich incorporates addition of exogenous chemical regulators.In this case, the model admits the possibility of tumour regression,and the therapeutic implications of this are discussed.     

Sudden and Fatal Malfunction of a Durata Defibrillator Lead due to External Insulation Failure

Defibrillator lead malfunction can be a disastrous complication, leading to loss of protection from sudden cardiac death in a high‐risk patient population. Recognition of lead‐specific risk for failure can assist in development of focused screening or surveillance, as in the case of the Riata lead (St. Jude Medical, St. Paul, MN, USA) or the Sprint Fidelis lead (Medtronic Inc., Minneapolis, MN, USA). A case of defibrillation failure secondary to a Durata lead insulation failure is presented. A brief review of the literature and current St. Jude Medical implantable cardiac defibrillator lead design is presented. Identification of arcing is identified as a potential sign of catastrophic insulation failure.