Associations between cigarette smoking and mitochondrial DNA abnormalities in buccal cells.

DNA alterations in mitochondria are believed to play a role in carcinogenesis and are found in smoking-related cancers. We sought to replicate earlier findings for the association of smoking with increased mitochondrial DNA (mtDNA) content in buccal cells and further hypothesized that there would be an increased number of somatic mtDNA mutations in smokers. Buccal cells and blood lymphocytes were studied from 42 healthy smokers and 30 non-smokers. Temporal temperature gradient electrophoresis screening and sequencing was used to identify mtDNA mutations. The relative mtDNA content was determined by real-time polymerase chain reaction. Assuming that mtDNA in lymphocytes represents the inherited sequence, it was found that 31% of smokers harbored at least one somatic mtDNA mutation in buccal cells with a total of 39 point mutations and 8 short deletions/insertions. In contrast, only 23% of non-smokers possessed mutations with a total of 10 point mutations and no insertions/deletions detected. mtDNA somatic mutation density was higher in smokers (0.68/10 000 bp per person) than in non-smokers (0.2/10 000 bp per person). There was a statistically significant difference in the pattern of homoplasmy and heteroplasmy mutation changes between smokers and non-smokers. Whereas non-smokers had the most mutations in D-loop region (70%), smokers had mutations in both messenger RNA encoding gene (36%) and D-loop region (49%). The mean ratio of buccal cells to lymphocytes of mtDNA content in smokers was increased (2.81) when compared with non-smokers (0.46). These results indicate that cigarette smoke exposure affects mtDNA in buccal cells of smokers. Additional studies are needed to determine if mitochondrial mutation assays provide new or complementary information for estimating cigarette smoke exposure at the cellular level or as a cancer risk biomarker.

Depression, constructive thinking and patient satisfaction in cardiac treatment adherence.

Many patients fail to adhere to prescribed treatment regimens, particularly patients who are depressed. This study examined the link between depression and adherence among 92 patients undergoing post-operative cardiac rehabilitation. Self-reported adherence was measured in terms of both general recommendations and specific health behaviours. Greater depression was associated with general - but not specific - adherence, and this relationship was mediated by lower satisfaction with their doctor - patient interactions. The link between depression and patient satisfaction was itself mediated by less constructive thinking among patients. These results suggest that adherence among cardiac rehabilitation patients may be enhanced by addressing patients' cognitive coping, and by improving the quality of their doctor - patient interactions.

Neighborhood racial composition and availability of asthma drugs in retail pharmacies.

This study investigated whether there may be differences in the availability of asthma drugs and equipment in retail pharmacies in nonwhite and white neighborhoods in the District of Columbia. We conducted a telephone survey of a random sample of 38 retail pharmacies in predominately black or white neighborhoods. No differences in the reported availability of asthma drugs and equipment by neighborhood were found, although there was variability in availability of certain asthma drugs and limited availability of asthma equipment. Low demand was the most frequent reason cited by pharmacists regarding why asthma drugs or equipment were not in stock.