Advertising, price, income and publicity effects on weekly cigarette sales in New Zealand supermarkets

Total cigarettes (all brands) sold weekly by a panel of 60 New Zealand supermarkets were monitored electronically for 42 weeks, a period when cigarette advertisements were in plain format with strong, varied disease warnings. Real cigarette price, newspaper advertising of old, regular and upmarket brands, and the number of newspaper news items on smoking issues were inversely associated with cigarette sales. Tending to increase total sales (all brands) were: more non-shopping days in the current week, and in the week following; volume of grocery items purchased, to indicate income and store traffic; and real advertising expenditure in newspapers for new downmarket cigarette brands, particularly one heavily-advertised brand (Peter Jackson) which was in late 1989 smoked by 4% of teenage smokers. All factors when interacting, explained 93% of changes in weekly cigarette sales. Most of the change occurred in the same week, and was 90% in place after a further 3 weeks. Newspapers, by doubling news coverage of smoking issues or by banning cigarette advertisements, can lower cigarette consumption as much as can a 10% price increase.     

THE ACTION OF PTEROYL GLUTAMIC ACID AND NATURAL SOURCES OF FOLIC ACID ON BLOOD DYSCRASIAS INDUCED BY SULFONAMIDE DRUGS

Sulfanilamide, sulfathiazole, and sulfadiazine have been fed at 1 per cent levelsin highly purified diets and their effect on growth, mortality, and blood dyscrasiascompared with that of sulfasuxidine.

The soluble drugs produce conditions which are similar to those produced bysulfasuxidine. The growth depression is alleviated in large measure in the case ofsulfanilamide and to a lesser extent for sulfathiazole and sulfadiazine by folic acid.liver extract powder, and dried yeast extract as well as by para-aminobenzoic acid,

The blood dyscrasias due to sulfanilamide, sulfathiazole, and sulfadiazine aresevere leukopenia, granulocytopenia, and mild-to-severe anemia. These are uniformly prevented or the severity greatly curtailed by feeding folic acid, liver extract powder, or dried yeast extract. PABA has a lesser effect in the amounts fed.

Liver extract powder seems to have a beneficial effect on growth and mortalitywhich is not shown by the other supplements. Both free and conjugated folic acid(as yeast extract and in liver extract powder 1:20) are active in combating thedyscrasias.

Evidence from in vitro experiments with Str. haemolyticus (B Lancefield) indicates that neither folic acid, liver extract powder, nor dried yeast extract in ratiosto sulfonamide which are effective in preventing the blood dyscrasias will inhibitor block the bacteriostatic action of the sulfonamide drugs in vitro.

It is suggested that the action of folic acid, liver powder, and yeast extract is notwholly explained by alleviating a folic acid deficiency caused by intestinal bacteriostasis due to the drugs, but by an increased demand of the animals for folicacid in the presence of certain sulfonamides.

Note: We are indebted to Harold Buskirk, Alice Bergdahl, Hallie Ferguson, E. M. Stapert, F. La Plante,and Evon Saggio for valuable assistance in carrying out the experimental work reported here.

     

A New Defibrillator Discrimination Algorithm Utilizing Electrogram Morphology Analysis

Inappropriate therapies delivered by implantable cardioverter defibrillators (ICDs) for supraventricular arrhythmias remain a common problem, particularly in the event of rapidly conducted atrial fibrillation or marked sinus tachycardia. The ability to differentiate between ventricular tachycardia and supraventricular arrhythmias is the major goal of discrimination algorithms. Therefore, we developed a new algorithm, SimDis, utilizing morphological features of the shocking electrograms. This algorithm was developed from electrogram data obtained from 36 patients undergoing ICD implantation. An independent test set was evaluated in 25 patients. Recordings were made in sinus rhythm, sinus tachycardia, and following the induction of ventricular tachycardia and atrial fibrillation. The arrhythmia complex is defined as wide if the duration is at least 30% greater than the template in sinus rhythm. For narrow complexes, four maximum and minimum values were measured to form a 4-element feature vector, which was compared with a representative feature vector during normal sinus rhythm. For each rhythm, any wide complex was classified as ventricular tachycardia. For narrow complexes, the second step of the algorithm compared the electrogram with the template, computing similarity and dissimilarity values. These values were then mapped to determine if they fell within a previously established discrimination boundary. On the independent test set, the SimDis algorithm correctly classified 100% of ventricular tachycardias (27/27), 98% of sinus tachycardias (54/55), and 100% of episodes of atrial fibrillation (37/37). We conclude that the SimDis algorithm yields high sensitivity (100%) and specificity (99%) for arrhythmia discrimination, using the computational capabilities of an ICD system.     

Inappropriate Implantable Cardioverter-Defibrillator Therapy Due to the Detection of Premature Ventricular Complexes

Inappropriate shocks delivered by implantable cardioverter-defibrillators may occur in 15%-40% of patients treated with these devices. This article describes a rare cause for inappropriate shocks. Two patients received inappropriate shocks due to the presence of premature ventricular complexes during attempted reconfirmation of ventricular fibrillation. Knowledge of device algorithms for detection and reconfirmation of ventricular fibrillation, designed to have a high degree of sensitivity and therefore lower specificity, allows for reprogramming to avoid further inappropriate shocks.     

Electrophysiological Studies on Cardiac Catheter Ablation

Clinical and animal investigations have pointed out that high energy electrical shocks are associated with the development of cardiac arrhythmias and with variable success in permanent ablation. The effects of electrode configuration and location on the size of the recorded electrogram was investigated to help explain variable catheter ablation results. We analyzed the cellular effects of catheter ablation shocks and found depression of resting potential, action potential amplitude, dV/dt and action potential duration. The most severe effects were noted with high current densities in tissues located between the cathode and anode. Damage was worse nearest the cathode. Similar cellular studies were completed using argon laser photoablation. Again, there was a decrease in resting potential, action potential amplitude and dV/dt. Laser energy led to a more focal region of myocardium void of action potentials and the border zone of injury was smaller. We also investigated the effects of lower energy shocks)1 to 10 joule) on cardiac tissues. Using microelectrodes, we observed that the membrane potential can "hang up" at the depolarized levels for varying periods of time and that conduction is altered during this membrane "hang-up" period. The duration and membrane hang-up level correlated with shock intensity and shock duration. Sequential shocks resulted in additive membrane "hang-up". We believe that membrane hang-up may be associated with brief arrhythmias observed following catheter ablation since conduction, refractoriness and excitability are all altered.