Noninvasive assessment and quantification of tumour vascularisation using MRI and CT in a tumour model with modifiable angiogenesis - An animal experimental prospective cohort study.

BACKGROUND: To investigate vascular-related pathophysiological characteristics of two human lung cancers with modifiable vascularisation using MRI and CT. METHODS: Tumour xenografts with modifiable vascularisation were established in 71 rats (approval by the Animal Care Committee was obtained) by subcutaneous transplantation of two human non-small-cell lung cancer (NSCLC) cells (A549, H1299) either alone or co-transplanted with vascular growth promoters. The vascularity of the tumours was assessed noninvasively by MRI diffusion-weighted-imaging (DWI), T2-weighted, and time-of-flight (TOF) sequences) as well as contrast-enhanced CT (CE-CT), using clinical scanners. As a reference standard, histological examinations (CD-31, fluorescent beads) were done after explantation. RESULTS: Microvessel density (MVD) was higher in co-transplanted tumours (171 ± 19 number/mm2) than in non-co-transplanted tumours (111 ± 11 number/mm2; p = 0.002). Co-transplanted tumours showed higher growth rates and larger tumour vessels at TOF-MRI as well as larger necrotic areas at CE-CT. In co-transplanted tumours, DWI revealed higher cellularity (lower minimal ADCdiff 166 ± 15 versus 346 ± 27 mm2/s × 10-6; p < 0.001), highly necrotic areas (higher maximal ADCdiff 1695 ± 65 versus 1320 ± 59 mm2/s × 10-6; p < 0.001), and better-perfused tumour stroma (higher ADCperf 723 ± 36 versus 636 ± 51 mm2/s × 10-6; p = 0.005). Significant correlations were found using qualitative and quantitative parameters: maximal ADCperf and MVD (r = 0.326); maximal ADCdiff and relative necrotic volume on CE-CT (r = 0.551); minimal ADCdiff and MVD (r = -0.395). CONCLUSIONS: Pathophysiological differences related to vascular supply in two human lung cancer cell lines with modifiable vascularity are quantifiable with clinical imaging techniques. Imaging parameters of vascularisation correlated with the results of histology. DWI was able to characterise both the extent of necrosis and the level of perfusion.

Cigarette smoking, dietary intake, and physical activity: effects on body fat distribution--the Normative Aging Study.

Studies have indicated that although smokers weigh less than nonsmokers, smokers have greater waist-to-hip circumference ratios after adjustment for age and body mass index (BMI). The purpose of this investigation was to determine whether factors associated with smoking, such as dietary intake, alcohol intake, and physical activity, modified or confounded the relationship between smoking and body fat distribution. The study used cross-sectional data for 765 men aged 43-85 y from the Normative Aging Study. Current smokers were found to have a greater amount of central adiposity, as represented by the abdomen-to-hip circumference ratio (abdomen-hip ratio), than did former smokers and people who never smoked after adjustment for age, BMI, dietary and alcohol intakes, and physical activity. Multiple-linear-regression analysis revealed that physical activity was negatively associated with and alcohol intake was positively associated with the abdomen-hip ratio. These results suggest a direct effect of smoking on body fat distribution, independent of other smoking-related behaviors.

The influence of situation and coping on relapse crisis outcomes after smoking cessation.

Examines the influence of situational characteristics and coping on the outcome of a relapse crisis for 232 Ss followed for 1 month after a self-initiated smoking cessation attempt. Survival of a relapse crisis was most strongly related to the number of coping strategies used. All coping strategies were equally effective; furthermore, combining cognitive and behavioral coping strategies was not more effective than using multiple cognitive or multiple behavioral strategies. During the second half of the follow-up period (Weeks 3 and 4 postcessation), the presence of smokers resulted in a decreased likelihood of coping and an increased likelihood of smoking. In addition, active coping was marginally related to higher baseline levels of motivation to quit. When motivation and the presence of smokers were controlled, however, coping still significantly predicted outcome. Results are discussed with reference to previous relapse studies.

Self-help approaches to smoking cessation: a report from the normative aging study.

Self-quitters make up by far the largest proportion of ex-cigarette smokers, yet this population has not been extensively characterized to date. We compared male self-quitters (N = 191) and age-matched recidivists (N = 110) on smoking histories, psychosocial attributes and quitting methods. A number of significant relationships were found, some of which may have clinical implications. those who substituted cigars or pipes for cigarettes were nearly four times more likely to be successful, and those who reported consuming more food/snacks after quitting were 80% more likely to be successful quitters. Subjects who reported using no coping strategies in former smoking settings after cessation because they had no urges to smoke in these settings were also much more likely to be successful quitters. Recidivists were more likely to report using physical activity as a means of coping with temptations to smoke, and were somewhat older at the time of the quit attempt. Withdrawal symptoms and psychosocial stress were reported as reasons for relapse by early relapsers, while late relapsers reported being around other smokers on social occasions, and psychosocial stress.

Retrospective analysis in smoking cessation research.

The use of retrospective data in smoking research represents possible sources of bias resulting from: (1) baseline incomparability of current, former, and non-smokers, (2) instability of parameters under investigation, and (3) difficulties in recall. A self-report measure of smoking motives was employed in a longitudinal design to examine bias associated with retrospective data analysis. Thirty-six pairs of former smokers and recidivists (smokers who had tried to quit) were matched on age and amount smoked. Although initial responses for both groups were comparable, former smokers were significantly higher on smoking motive factors after quitting compared to recidivists who stayed essentially the same. The findings suggest that mean differences in smoking motives between recidivists and former smokers assessed cross-sectionally may not accurately reflect the magnitude of the differences that existed when both groups were smoking.

Predictors of smoking relapse among self-quitters: a report from the Normative Aging Study.

We followed 235 adults for one year after a self-initiated attempt to stop smoking cigarettes. Relapse rates were much larger than expected in the early days and weeks after the quit attempt. Approximately 62% had relapsed by 2 weeks after their quit dates. Those who smoked any cigarettes at all in the post-cessation period (i.e., lapsed) had a 95% probability of resuming their regular pattern of smoking subsequently. Shorter periods of abstinence on prior quit attempts, greater pre-cessation consumption of alcoholic beverages, and lower pre-cessation levels of confidence in quitting were related to relapse. In addition, abstainers who reported decreased confidence after cessation concerning their ability to maintain abstinence were more likely to relapse thereafter. The presence of a greater proportion of smokers in the subjects' environment also increased the likelihood of relapse. Demographic variables such as age, gender, and education level did not predict relapse. Likewise, neither baseline psychosocial stress levels, nor post-cessation increases in stress were related prospectively to relapse. Clinical implications of finding are discussed.