Could mainstream anti-smoking programs increase inequalities in tobacco use? New Zealand data from 1981-96.

OBJECTIVE: To examine changes in the socio-economic and ethnic distribution of smoking in the New Zealand population from 1981 to 1996, and to consider the implication of these data for policies aimed at reducing tobacco consumption. METHODS: Cross-sectional data were taken from 4.7 million respondents to the 1981 and 1996 New Zealand Censuses and 4,619 participants in a 1989 national survey, aged 15 to 79 years. Smoking prevalence rates were calculated by socio-economic position and ethnicity. RESULTS: Smoking prevalence fell in the period 1981-96 in every population group. However, socio-economic and ethnic differences in smoking increased in relative terms. Smoking prevalence ratios comparing the least advantaged with the most advantaged groups increased in men from 1.20 to 1.53 by income, 1.54 to 1.85 by education, and 1.49 to 1.67 by ethnicity. In women, prevalence ratios increased from 1.17 to 1.51 by income, 1.55 to 2.02 by education, and 1.85 to 2.20 by ethnicity. The greatest increase in socio-economic differences may have occurred during the 1980s, the period of greatest overall decline in total population smoking. CONCLUSIONS: Socio-economic and ethnic disparities in New Zealanders' smoking patterns increased during the 1980s and '90s, a period of significant decline in overall smoking prevalence. IMPLICATIONS: Public health programs aimed at reducing tobacco use should pay particular attention to disadvantaged, Indigenous and ethnic minority groups in order to avoid widening relative inequalities in smoking and smoking-related health outcomes.

A method for reversible permeabilization of isolated rat ventricular myocytes.

A method is described that enables the cell membrane of isolated rat ventricular myocytes to be permeabilized and resealed while maintaining cell viability. Streptolysin O, a cholesterol-binding cytolysin, was used to form pores in the surface membrane; subsequent incubation with 5% fetal bovine serum was used to reverse this permeabilization. The efficacy of membrane permeabilization and resealing was ascertained using a simultaneous double-staining technique using propidium iodide, a marker for cells with permeabilized membranes, and fluorescein diacetate, a marker for viable cells. This procedure allowed a distinction to be made between dead cells, unpermeabilized cells and viable cells that had been successfully permeabilized and resealed. The accessibility of the cell interior during permeabilization was investigated by including fluorescein isothiocyanate (FITC)-labelled dextrans (11, 38 and 148 kDa) and bovine serum albumin (67 kDa) in the permeabilization buffer, and localizing the FITC label using confocal microscopy following resealing. The confocal images showed that these molecules entered the cells and were retained after resealing. Following the permeabilization-resealing protocol, cells appeared to have both normal morphology and response to electrical stimulation. Thus this appears to be a cheap, simple and effective method to introduce relatively large molecules into cardiac myocytes.