Ready, set, go! Motivation and lifestyle habits in parents of children referred for obesity management.

BACKGROUND: Parents play a fundamental role in helping children with obesity to make and maintain healthy lifestyle changes. OBJECTIVE: This study aimed to characterize stages of engagement to change nutrition and physical activity habits among parents whose children with obesity were enrolled in obesity management and examine differences in parents' own nutrition and physical activity habits according to their stage of engagement. METHODS: Medical records of 113 children (body mass index [BMI] ≥95th percentile) enrolled in an outpatient weight management clinic were reviewed for baseline (cross-sectional) data. Parents completed the Weight Loss Behavior-Stage of Change Scale to assess the degree of engagement in making healthy changes to their lifestyle behaviours. Latent class analysis was used to classify parents into distinct clusters by grouping individuals with similar ratings of stages of engagement regarding nutrition- and physical activity-related behaviours. RESULTS: Parents' engagement in healthy lifestyle behaviours varied (more engaged [n = 43]; less engaged [n = 70]). A greater proportion of parents in the more engaged group was in action and/or maintenance stages of changing their lifestyle habits. The more engaged group was less overweight than the less engaged group (BMI = 28.5 vs. 33.3 kg m(-2); P < 0.05). Further, the more engaged group consumed fewer total calories, calories from fat, trans fat and carbohydrates vs. their less engaged peers (P < 0.05). Compared with the less engaged group, the more engaged group consumed more daily servings of vegetables and fruits (4.9 vs. 3.9, P < 0.05) and accumulated more steps per day (9130 vs. 7225; P < 0.05). The more engaged group was also more likely to meet daily recommendations for vegetable and fruit intake (48.8 vs. 24.3%; P < 0.05) and physical activity (42.9 vs. 22.9%, P < 0.05). CONCLUSIONS: Parents of children with obesity varied in their degree of engagement in making healthy changes to their lifestyle behaviours, and those categorized as more engaged already demonstrated positive lifestyle behaviours. Information regarding parents' degree of engagement in healthy behaviours can inform clinical recommendations, especially when parents represent the primary agents of change in families trying to manage paediatric obesity.

Cardiac sodium channels expressed in a peripheral neurotumor-derived cell line, RT4-B8.

RT4-B is one of several cell lines derived from a multipotent stem cell line, RT4-AC, which originated from a rat peripheral neurotumor. Based on Northern blot and ribonuclease protection experiments, RT4-B8 cells have been proposed to express rat cardiac Na channel mRNA as the major isoform. We report here direct electrophysiological evidence that the expressed voltage-gated Na channels in the RT4-B8 cell line are of the cardiac phenotype with no evidence for subpopulations expressing other Na channel isoforms. Current activation half point (conductance) was -41 +/- 5 mV (n = 7) and the steady-state voltage-dependent availability half point was -89 +/- 1 mV. As expected for cardiac Na channels, the half concentration of block for tetrodotoxin block was 0.74 microM, for saxitoxin (STX) was 0.15 microM, and for the class 2B divalent cation Cd2+ was 67 microM. Block was well described by single-site dose-response relationships with no indication of a subpopulation with "neuronal" affinity. Single-channel conductance (140 mM Na+) was 10 pS and predicted the average number of channels open at peak Na current to be 3 channels/microns2. [3H]STX binding data were also consistent with a single population of low-affinity STX binding sites and predicted channel density to be 11 sites/microns2. No inwardly or outwardly rectifying K or Ca currents were detected electrophysiologically, although in some cells a small time-independent Cl current was detected. Reverse transcription-polymerase chain reaction of mRNA isolated from RT4-B8 cells demonstrated the presence of rat cardiac (rH1) and brain IIa alpha-subunit mRNA, as well as mRNA for the Na channel beta 1-subunit. Northern blot analysis confirmed the predominance of the rat cardiac Na mRNA compared with brain IIa. The beta 1-subunit mRNA levels were significantly lower than those detected in rat brain and heart mRNA but were comparable to the low level of beta 1-subunit mRNA detected in isolated rat ventricular myocytes.