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.     

The effects of oral digoxin therapy in primary mitral leaflet prolapse

The effects of oral digoxin on symptoms, arrhythmias, exercisetolerance and echocardiographic function in primary mitral leafletprolapse were studied in 23 patients using a double-blind crossoverprotocol. Digoxin reduced the incidence and severity of chest pain comparedwith both the control (P = 0.0002) and placebo (P = 0.0005)periods. We found a high (83%) incidence of predominantly minor arrhythmiason continuous ambulatory monitoring. Digoxin favourably affectedthe incidence of frequent supraventricular ectopic beats andsupraventricular tachycardia but was associated with a significantnumber (P<0.0025) of asymptomatic bradyarrhythmias. In patientswith frequent ventricular ectopics, digoxin had no consistenteffect. No difference in exercise tolerance between treatment pericdswas found on maximal treadmill stress testing, but digoxin administrationresulted in an increase in echocardiographic mean circumferentialfibre shortening velocity (P<0.01) and fractional shorteningpercent (P<0.01). This study demonstrates the efficacy of oral digoxin therapyin ameliorating chest pain in patients with primary mitral leafletprolapse and suggests a favourable effect on supraventriculararrhythmias in such patients.     

Sequential Studies of Circulating Immune Complexes in Gynecological Malignancies*

ABSTRACT: Immune complexes have been assayed sequentially in seventeen patients with gynecological malignancies, using a polyethylene glycol precipitation assay and a Clq solid phase assay. The PEG assay demonstrated a good correlation between PEG assay levels and the course of disease in nine out of eleven patients with ovarian adenocarcinoma and all four patients with endometrial carcinoma. Three of the patients with ovarian cancer were not treated with aggressive surgery and exhibited equivocal signs of progressive disease during subsequent follow-up. There was no clear relationship between immune complex levels and the clinical condition in two of these patients. The ClqSP assay result did not correlate with disease progression and, in several instances, progressive disease was associated with a fall in ClqSP values. In a further series, twelve out of twenty patients with ovarian cancer who were initially in remission from disease but subsequently relapsed demonstrated elevated levels of PEG immune complexes between one and three months before clinical detection of recurrence whereas patients who stayed in remission maintained normal levels of PEG immune complexes. These data suggest that the PEG assay may be of clinical value in the monitoring of ovarian cancer patients with minimal residual disease following surgery.     

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.     

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.     

Effects of Smoking and Smoking Deprivation on the Articulatory Loop of Working Memory

This study examined the effects of smoking and smoking deprivation on the articulatory loop of working memory. Forty subjects (20 smokers and 20 non-smokers) performed tasks involving serial recall of letters on two occasions 1 week apart. In each test one part was conducted with articulatory suppression and the other without it. The smokers completed one test following 12 h of smoking deprivation, and the other after smoking a cigarette. The order of suppression/non-suppression conditions and the order of smoking and smoking deprivation were balanced across subjects. The results showed that deprived smokers performed significantly worse than both smoking smokers and non-smokers in the task without suppression. Although all the subjects performed significantly worse whilst under articulatory suppression, smoking status was not found to influence performance here. These results imply that smoking has the effect of returning the smoker to a comparable level of performance to that seen in non-smokers, and suggest that smoking abstinence has a negative effect when performance involves the articulatory loop. © 1997 John Wiley & Sons, Ltd.