Baseline data and design for a randomized intervention study of dietary change in religious organizations

BACKGROUND: Reducing dietary fat has been identified as a potential means of preventing chronic disease. Several studies have identified methods of changing dietary fat consumption in small, intensive intervention settings. Fewer studies have examined how to improve dietary habits of individuals in the general public. METHODS: The Eating for a Healthy Life (EHL) project was a randomized trial [n = 40 religious organizations (ROs) and 2175 individuals, 1099 in intervention]. The study tested an intervention package of self-help books, motivational messages, and social interactions designed to change dietary behaviors (lowering fat, increasing fruit and vegetable consumption) among members of religious organizations aged 18 and over. The primary outcomes are fat- and fruit- or vegetable-related behaviors measured using the Fat and Fiber Behavior (FFB) Questionnaire. RESULTS: Religious organizations and their members participated fully in the initial study activities. CONCLUSIONS: This study will support a rigorous test of the intervention package.     

The effects of carbon monoxide on respiratory chemoreflexes in humans

As protection against low-oxygen and high-carbon-dioxide environments, the respiratory chemoreceptors reflexly increase breathing. Since CO is also frequently present in such environments, it is important to know whether CO affects the respiratory chemoreflexes responsiveness. Although the peripheral chemoreceptors fail to detect hypoxia produced by CO poisoning, whether CO affects the respiratory chemoreflex responsiveness to carbon dioxide is unknown. The responsiveness of 10 healthy male volunteers were assessed before and after inhalation of approximately 1200 ppm CO in air using two iso-oxic rebreathing tests; hypoxic, to emphasize the peripheral chemoreflex, and hyperoxic, to emphasize the central chemoreflex. Although mean (SEM) COHb values of 10.2 (0.2)% were achieved, no statistically significant effects of CO were observed. The average differences between pre- and post-CO values for ventilation response threshold and sensitivity were -0.5 (0.9) mmHg and 0.8 (0.3) L/min/mmHg, respectively, for hyperoxia, and 0.7 (1.1) mmHg and 1.2 (0.8) L/min/mmHg, respectively, for hypoxia. The 95% confidence intervals for the effect of CO were small. We conclude that environments with low levels of CO do not have a clinically significant effect acutely on either the central or the peripheral chemoreflex responsiveness to carbon dioxide.     

Self-perceived health among Canadian opiate users: a comparison to the general population and to other chronic disease populations

BACKGROUND: There are an estimated 40,000 to 90,000 injection opiate users in Canada. The social, economic and health consequences of opiate addiction have been well documented. However, there are no data on the self-perceived health status of opiate users in Canada. Therefore, the goal of this research is to gain an understanding of the self-perceived health status of opiate users by comparing the health-related quality of life of opiate users to chronic disease populations and to the general population. METHODS: The SF-36 was administered to a nonrandom sample of 143 opiate users entering low-threshold methadone treatment. Two sample t-tests were performed to assess statistical differences, at a 5% level of significance, between population scores across SF-36 dimensions. RESULTS: Opiate users perceived both their mental and physical health as worse than the general population and individuals with minor and serious medical problems, but comparable to those with diagnosed psychiatric illnesses. CONCLUSIONS: Methadone treatment services should incorporate both primary care and psychiatric care into their programs, or at the very least secure appropriate referral mechanisms to ancillary services to ensure that the health concerns of opiate users are dealt with in the context of their treatment program.     

Evaluating the validity of animal models for research into therapies for immune-based disorders

The last few decades of the 20th century have shown an intensified search for safer and more effective medications against chronic diseases that burden ageing societies of the western world. The impressive development of biotechnological production techniques has greatly facilitated the pharmaceutical development of relatively non-toxic biological molecules. However, despite the huge investments, only a few effective therapies for immune-based diseases have reached the clinic. In this article we use examples from monoclonal antibody trials to discuss the validity and predictive strength of the animal models currently used for the development of effective therapies.     

Reduction of TSG101 protein has a negative impact on tumor cell growth

TSG101 was defined originally as a tumor-suppressor gene, raising the expectation that absence of the encoded protein should lead to increased tumor cell growth and, perhaps, increased tumor cell aggressiveness. We have used the RNA interference (RNAi) technique to downregulate TSG101 in PC3 (prostate cancer) and MDA-MB-231 (breast cancer) cells. An approximately 85% selective downregulation at the protein level was achieved in both cell lines over a period of 12 days as detected by Western blotting. This treatment resulted in inhibition of tumor cell growth, with a decreased level of TSG101 causing partial cell cycle arrest at the G(1)/S boundary and a reduction in the rate at which cells passed from G(2) through mitosis and back into G(1). In both cell lines, the percentage of cells in S-phase was reduced significantly at day 4 after the TSG101 siRNA transfection (27% vs. 41% in MDA-MB-231 cells; 22% vs. 39% in PC3 cells). Additionally, RNAi-mediated downregulation of TSG101 reduced the colony formation capacities of both cancer cell lines. Rather more surprisingly, TSG101 downregulation affected the migratory activity of the MDA-MB-231 cells, independent of any effect on proliferation. Thus, in a Transwell assay, after 4-hr incubation, 36.0% of control MDA-MB-231 cells had migrated to the lower chamber vs. 7.3% of TSG101-downregulated cells (p < 0.001; scrambled control, 36.5%). These results show that the TSG101 gene does not comply with the usual characteristics of a tumor-suppressor gene; rather, its expression may be necessary for activities associated with aspects of tumor progression.     

Target volume uncertainty and a method to visualize its effect on the target dose prescription

PURPOSE: To consider the uncertainty in the construction of target boundaries for optimization, and to demonstrate how the principles of mathematical programming can be applied to determine and display the effect on the tumor dose of making small changes to the target boundary. METHODS: The effect on the achievable target dose of making successive small shifts to the target boundary within its range of uncertainty was found by constructing a mixed-integer linear program that automated the placement of the beam angles using the initial target volume. RESULTS: The method was demonstrated using contours taken from a nasopharynx case, with dose limits placed on surrounding structures. In the illustrated case, enlarging the target anteriorly to provide greater assurance of disease coverage did not force a sacrifice in the minimum or mean tumor doses. However, enlarging the margin posteriorly, near a critical structure, dramatically changed the minimum, mean, and maximum tumor doses. CONCLUSION: Tradeoffs between the position of the target boundary and the minimum target dose can be developed using mixed-integer programming, and the results projected as a guide to contouring and plan selection.     

Restenosis rates following bifurcation stenting with sirolimus-eluting stents for de novo narrowings

The percutaneous treatment of coronary bifurcation stenoses is hampered by an increased rate of subsequent restenosis. The present study reports on the outcomes of a consecutive series of 58 patients with 65 de novo bifurcation stenoses treated with sirolimus-eluting stent implantation in both the main vessel and side branch. At 6 months, the incidence of major adverse cardiac events was 10.3% (1 death and 5 target lesion revascularizations) with no episodes of acute myocardial infarction or stent thrombosis.     

Influence and selection processes in friendships and adolescent smoking behaviour: the role of parental smoking

Concerning the role of parental smoking on development of adolescent smoking, most studies have exclusively focused on the direct effects of parents' smoking on youths' smoking. However, parental smoking may also play an indirect role by affecting youths' susceptibility to peer influences and by affecting friendship selection. Data were from a three-wave short-term longitudinal study of 1595 adolescents. Findings showed high similarities in smoking between reciprocal friends. Additionally, friend's smoking and parents' smoking were moderately related to adolescent smoking onset, but parents' smoking did not moderate the prospective association between best friend's smoking and adolescent smoking. Finally, parental smoking seemed to affect the selection of new friends: In particular, adolescents with smoking parents were most likely to become affiliated with smoking friends. There was no evidence that parental smoking affected termination of friendships.