Effect of optimizing the VV interval on left ventricular contractility in cardiac resynchronization therapy

Simultaneous biventricular pacing improves left ventricular (LV) function in patients with heart failure and LV asynchrony. Proper timing of the interventricular pacing interval (VV interval) may further optimize LV function. We investigated the acute hemodynamic response of changing the VV interval using maximum LV dP/dt (LV dP/dt_max) as a parameter for LV function. A biventricular pacemaker was implanted in 53 patients with severely impaired LV function, New York Heart Association class III and IV heart failure, left bundle branch block, LV asynchrony, and a QRS interval >150 ms. Optimization of the atrioventricular and VV intervals was based on measurement of LV dP/dt_max by a 0.014-in sensor-tipped pressure guidewire. Measurement of LV dP/dt_max was obtained without complications in all patients. In patients in sinus rhythm with ischemic cardiomyopathy or idiopathic dilated cardiomyopathy, mean improvements by simultaneous biventricular pacing were 17% and 18%, respectively. Patients in atrial fibrillation showed an improvement of 21%. Optimizing the VV interval resulted in further absolute increases of 8%, 7%, and 3%, respectively, in dP/dt_max in the 3 groups. Maximum dP/dt was achieved with LV pacing first in 44 patients, simultaneous right and left ventricular pacing in 6 patients, and right ventricular pacing first in 3 patients. The mean optimal VV intervals were 37 ± 32 ms in the atrial fibrillation group, 28 ± 30 ms in the idiopathic dilated cardiomyopathy group, and 52 ± 31 ms in the ischemic cardiomyopathy group. Optimization of the VV interval significantly increased LV dP/dt_max compared with simultaneous biventricular pacing, and such optimization could be easily, accurately, and reliably evaluated by a 0.014-in sensor-tipped pressure guidewire.     

Exploring the relationship between perceived barriers to healthy eating and dietary behaviours in European adults

Purpose

Dietary behaviours may be influenced by perceptions of barriers to healthy eating. Using data from a large cross-European study (N = 5900), we explored associations between various perceived barriers to healthy eating and dietary behaviours among adults from urban regions in five European countries and examined whether associations differed across regions and socio-demographic backgrounds.

Methods

Frequency of consumption of fruit, vegetables, fish, fast food, sugar-sweetened beverages, sweets, breakfast and home-cooked meals were split by the median into higher and lower consumption. We tested associations between barriers (irregular working hours; giving up preferred foods; busy lifestyle; lack of willpower; price of healthy food; taste preferences of family and friends; lack of healthy options and unappealing foods) and dietary variables using multilevel logistic regression models. We explored whether associations differed by age, sex, education, urban region, weight status, household composition or employment.

Results

Respondents who perceived any barrier were less likely to report higher consumption of healthier foods and more likely to report higher consumption of fast food. ‘Lack of willpower’, ‘time constraints’ and ‘taste preferences’ were most consistently associated with consumption. For example, those perceiving lack of willpower ate less fruit [odds ratio (OR) 0.57; 95% confidence interval (CI) 0.50–0.64], and those with a busy lifestyle ate less vegetables (OR 0.54; 95% CI 0.47–0.62). Many associations differed in size, but not in direction, by region, sex, age and household composition.

Conclusion

Perceived ‘lack of willpower’, ‘time constraints’ and ‘taste preferences’ were barriers most strongly related to dietary behaviours, but the association between various barriers and lower intake of fruit and vegetables was somewhat more pronounced among younger participants and women.

     

Vitamin D food fortification in European countries: the underused potential to prevent cancer deaths

European Journal of Epidemiology - Background: Meta-analyses of randomized controlled trials have shown that vitamin D supplementation reduces cancer mortality by 13%. Vitamin D fortification of...     

Effects of gemcitabine on cis-platinum-DNA adduct formation and repair in a panel of gemcitabine and cisplatin-sensitive or -resistant human ovarian cancer cell lines

Gemcitabine (dFdC) can increase the sensitivity of both cisplatin (CDDP)-sensitive and -resistant cell lines. It has been postulated that both formation and repair of platinum-(Pt)-DNA adducts are related to these effects. Therefore, we investigated the effects of dFdC on the formation and repair of Pt-DNA adducts in the human ovarian cancer cell line, A2780, and its CDDP- or dFdC-resistant variants, ADDP and AG6000, which have a different expression of various repair enzymes. Cells were exposed for 1 h to CDDP alone or combined with dFdC in IC50 concentrations, followed by a 1-h exposure to thiourea and, subsequently, by a drug-free period of 1, 3 or 23 h (i.e. 2, 4 or 24 h after CDPP +/- dFdC removal). Pt-DNA adducts were quantified with 32P-post-labeling. The gene expression of the repair enzymes, XPA and XRCC1, was the same in all 3 cell lines but ERCC1, ERCC3 and XPC were 2-6 times higher in AG6000 compared to A2780 cells. In contrast, both ERCC1 and ERCC3 were 10- and 1.5-fold lower in ADDP cells compared to A2780. The mismatch enzyme, MLH1, was lower in ADDP cells. At equally toxic CDDP concentrations, all cell lines formed comparable peak levels of total Pt-DNA adducts (36-48 fmol/microg DNA). However, the time at which peak levels were reached showed large variation. The repair of the adducts was very efficient in the resistant cell lines whereas, in A2780 cells, plateau levels were retained until 24 h after CDDP exposure. In A2780 cells, dFdC shifted the adduct peaks from 4 h to directly after CDDP exposure and increased peak levels by >3.9-fold. dFdC also enhanced the repair of adducts by >1.7-fold and increased the Pt-GG:Pt-AG ratio compared to CDDP alone by >1.4-fold. Overall, dFdC decreased the area under the Pt-DNA adduct-time curve (AUA0-25 h) in A2780 cells by 2.7-fold. In ADDP cells, dFdC shifted the adduct peaks from 2 to 4 h and increased them by >2.2-fold. dFdC also increased the Pt-GG:Pt-AG ratio during the repair process by 1.4-fold. Overall, dFdC increased the AUA0-25 h in ADDP cells by 1.7-fold. In AG6000 cells, dFdC increased the Pt-GG:Pt-AG ratio by 1.6-fold directly after exposure but did not clearly affect the AUA0-25 h. In conclusion, dFdC can affect both Pt-DNA adduct formation and repair, depending on the initial sensitivity of the cells.     

Associations between socioeconomic position and correlates of sedentary behaviour among youth: a systematic review

Existing research evidence indicates that children and adolescents of parents with a low socioeconomic position spend more time on sedentary behaviour than their counterparts. However, the mechanisms driving these differences remain poorly understood. The main aim of this systematic review was to summarize the evidence regarding the association between socioeconomic position and correlates of sedentary behaviour among youth (0–18 years) from developed countries. The literature search was conducted using MEDLINE, Embase, CINAHL and PsycINFO. A total of 37 studies were included. All but three studies examined screen‐based sedentary behaviours only. Methodological quality ranged from low to moderate. Education was the most commonly used indicator of socioeconomic position, followed by income. Socioeconomic position was inversely related to the presence of a TV in the child's bedroom, parental modelling for TV viewing, parental co‐viewing and eating meals in front of the TV. We found no/indeterminate evidence for an association between socioeconomic position and rules and regulations about screen time. The findings suggest possible factors that could be targeted in future intervention studies to decrease screen‐based sedentary behaviour in lower socioeconomic groups in particular.     

The effects of a lifestyle intervention on leisure-time sedentary behaviors in adults at risk: The Hoorn Prevention Study,a randomized controlled trial

Objective

This study set out to assess the short- and long-term effects of a primary care-based lifestyle intervention on different domains of leisure-time sedentary behaviors in Dutch adults at risk of type 2 diabetes and cardiovascular diseases.

Methods

Between 2007 and 2009, adults (n = 622) at risk were randomly assigned to a counseling intervention aimed at adopting healthy lifestyle behaviors, or a control group that only received health brochures. Follow-up measures were done after 6, 12 and 24 months. Linear regression analysis was used to examine between-group differences in self-report minutes per day sedentary behaviors, adjusted for baseline values. Stratified analyses were performed for sex and educational attainment.

Results

Seventy-nine percent (n = 490) of participants completed the last follow-up. Mean baseline sedentary behaviors were 254.6 min per day (SD = 136.2). Intention-to-treat analyses showed no significant differences in overall or domain-specific sedentary behaviors between the two groups at follow-up. Stratified analyses for educational attainment revealed a small and temporary between-group difference in favor of the intervention group, in those who finished secondary school.

Conclusions

A primary care-based general lifestyle intervention was not more effective in reducing leisure-time sedentary behaviors than providing brochures in adults at risk for chronic diseases.     

Motives for (not) participating in a lifestyle intervention trial

Background  

Non-participants can have a considerable influence on the external validity of a study. Therefore, we assessed the socio-demographic, health-related, and lifestyle behavioral differences between participants and non-participants in a comprehensive CVD lifestyle intervention trial, and explored the motives and barriers underlying the decision to participate or not.