Predictors of time spent outdoors among children: 5-year longitudinal findings

BACKGROUND

Given the importance of physical activity for health and age-related declines in physical activity, understanding influences on related behaviours, such as time outdoors, is crucial. This study aimed to understand individual, social and physical environmental influences on longitudinal changes in urban children's time outdoors.

METHODS

The time children spent outdoors in 2001, 2004 and 2006 (aged 5-6 and 10-12 years at baseline) was reported by their parents (n=421). In 2001, individual, social and physical environmental factors were self-reported by parents. Generalized estimating equations examined longitudinal relationships between baseline predictors and average change in time outdoors over 5 years.

RESULTS

Children's time outdoors significantly declined over time. "Indoor tendencies" inversely predicted time outdoors among younger and older boys, and younger girls. Social opportunities positively predicted time outdoors among younger boys, while "outdoor tendencies" positively predicted time outdoors among older boys. Parental encouragement for activity positively predicted time outdoors among younger and older girls, while lack of adult supervision for active play outdoors after school inversely predicted time outdoors among older girls and older boys.

CONCLUSION

Individual (indoor and outdoor tendencies) and social factors (social opportunities, parental encouragement and parental supervision) predicted children's time outdoors over 5 years. Interventions targeting reduced indoor tendencies, increased outdoor play with others, and increased parental encouragement and supervision are warranted.

Can social cognitive theory constructs explain socio-economic variations in adolescent eating behaviours? A mediation analysis

Adolescents of low socio-economic position (SEP) are less likely than those of higher SEP to consume diets in line with current dietary recommendations. The reasons for these SEP variations remain poorly understood. We investigated the mechanisms underlying socio-economic variations in adolescents' eating behaviours using a theoretically derived explanatory model. Data were obtained from a community-based sample of 2529 adolescents aged 12-15 years, from 37 secondary schools in Victoria, Australia. Adolescents completed a web-based survey assessing their eating behaviours, self-efficacy for healthy eating, perceived importance of nutrition and health, social modelling and support and the availability of foods in the home. Parents provided details of maternal education level, which was used as an indicator of SEP. All social cognitive constructs assessed mediated socio-economic variations in at least one indicator of adolescents' diet. Cognitive factors were the strongest mediator of socio-economic variations in fruit intakes, while for energy-dense snack foods and fast foods, availability of energy-dense snacks at home tended to be strong mediators. Social cognitive theory provides a useful framework for understanding socio-economic variations in adolescent's diet and might guide public health programmes and policies focusing on improving adolescent nutrition among those experiencing socio-economic disadvantage.

Phase I study of TP300 in patients (pts) with advanced solid tumors

2563

Background: TP300 (CH4556300) is a synthetic camptothecin analogue and potent topoisomerase I inhibitor designed to have superior efficacy, tolerability and pharmacokinetic (PK) characteristics compared to current inhibitors. Intravenous (i/v) TP300 undergoes rapid chemical conversion to the active compound CH0793076, then enzymatic conversion to an active metabolite, CH0793011. The objectives of this study were to determine the dose-limiting toxicities (DLTs), maximum-tolerated dose (MTD) and PK profiles of TP300; antitumor activity and pharmacodynamics (PD) were also evaluated. Methods: Eligible pts with refractory, advanced solid tumors who had adequate PS, hematologic, renal, and hepatic function were recruited into this open-label, modified- Fibonacci dose escalation (“3 + 3” pts/dose level, with expansion at the MTD) study. TP300 was given as a 1-hour i/v infusion 3-weekly; the starting dose was 1 mg/m2. The MTD was defined as the dose level below that where > 2 of 3–6 pts experienced DLT. PK profiles of TP300, CH0793076 and CH0793011 were analysed; DNA strand breaks in peripheral blood mononuclear cells (PBMCs) were measured with the comet assay as a PD marker. Results: 32 pts (m=20; f=12), median age 58 (range 31–72), received TP300 at doses of 1, 2, 4, 8, 12, then 10mg/m2. The MTD was 10mg/m2; DLTs seen at 12mg/m2 (2/4 pts) and 10mg/m2 (3/12 pts) included anaemia, thrombocytopenia and febrile neutropenia. Other grade 3/4 toxicities included lethargy, chills and lower back pain. Diarrhoea was uncommon. Seven pts, all previously treated with irinotecan, had disease stabilisation for 1.5–5 months. CH0793076 PK (AUC and Cmax) were linear from 1 to 10mg/m2. There was a strong PD relationship between CH0793076 AUC and fall in neutrophils, the threshold AUC for DLT neutropenia being 5 hr.umol/L. DNA strand breaks were detected consistently in PBMCs on completion of TP300 infusion . Conclusions: The Phase II starting dose will be 8mg/m2 because hematologic toxicity was seen in cycle 1 at the MTD. As the AUC of CH0793076 at MTD is substantially greater than that of SN38 in pts treated with irinotecan, and CH0793076 is almost equipotent to SN38 pre-clinically, a PK advantage for TP300 is confirmed. Further investigation is warranted.

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Phase I dose-escalating study of PM02734 in a 24-hour infusion schedule every 21 days in advanced solid tumors

2511

Background: PM02734 is a chemically synthesized depsipeptide with a broad spectrum of activity against solid tumors in vitro (breast, colon, lung, neuroblastoma, prostate, sarcoma and thyroid) and in vivo (breast, prostate, melanoma); as well as an acceptable non-clinical toxicology profile. Methods: Patients (pts) with metastatic or advanced solid tumors were enrolled in a phase I, open-label, dose-escalating study to assess safety, tolerability, pharmacokinetics (PK), and to identify the dose limiting toxicity (DLT) and recommended dose (RD) of PM02734 infused over 24 hours every 21 days (d). The starting dose was 0.48 mg/m2. Cohorts of 1–6 pts were treated at different dose levels. Results: Thirty seven pts were treated in this study. The median age was 55 years (40–75), sex: males/females 20/19. The median PS was 1 (range 0–2). The most frequent cancer types were colon/ gastric/ sarcoma (n=8/5/5). Most patients were heavily pretreated, with a median of prior therapy lines of 4 (1–12). Patients were treated at 8 dose levels (0.48, 0.72, 1.0, 1.6, 2.4, 3.6, 5.4, and 6.8 mg/m2), the MTD was 6.8 mg/m2 and the RD was 5.4 mg/m2 (10 mg flat dose).Common toxicities grade ≤ 2 included asthenia, nausea/emesis, lymphopenia, injection site reactions and asymptomatic elevated transaminases (TAs). DLT were grade 3 asymptomatic, reversible TA elevations at 6.8 mg/m2. Preliminary PK data is characterized by long half life (>100 h), a wide distribution and high inter-patient variability. Clearance was not correlated with dose or body surface area (BSA), therefore, flat dose was implemented and the RD was explored with this schedule. Efficacy data showed one complete response (CR) of +28 months observed in a pt with metastatic large cell esophageal carcinoma, and five more showed stable disease (SD) for more than 3 months in different histologies. Conclusions: PM02734 shows to be safe, well tolerated and with evidence of activity (1 CR and 5 SD > 3 months) in pts with advanced solid tumors. The DLT was grade 3 asymptomatic and reversible TA elevations, and the RD for further phase II studies is 10 mg.

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Preliminary results of an open-label phase I pharmacokinetic/pharmacodynamic study of JNJ26481585: Early evidence of antitumor activity

e13504

Background: JNJ26481585 is a novel orally active pan-histone deacetylase inhibitor (HDACI) which showed potent antitumor efficacy in a wide range of animal tumor models. Methods: A 2-stage accelerated titration design Phase I trial was conducted to characterize safety, establish the maximum tolerated dose (MTD) and determine pharmacokinetics in patients (pts) with refractory solid tumors, of performance status <2 and with adequate hematologic, renal, hepatic and cardiac function. The drug was administered orally, once daily in 3 weekly cycles. Results: To date, 9 pts (median age 59; range 32–74) have been treated at 4 dose levels (DL): 2 (2 pts), 4 (2 pts), 8 (3 pts), and 12 (2 pts) mg. The median number of cycles administered was 2 (range 1–9). Dose-limiting toxicity was seen at 12mg (CTCAE Grade [G] 3 non-sustained ventricular tachycardia [VT] [1 pt] and G3 fatigue [1 pt]) and the 8mg cohort is being expanded. Other toxicity observed at 12mg comprised G2 palpitations with QT prolongation (1 pt), G2 anorexia (1 pt), G2 vomiting (1 pt) and G2 dysgeusia (1 pt). At 8mg, 1 pt on warfarin developed a G2 INR increase. Non-specific ECG changes were observed from the 2mg DL onwards. The drug was generally well tolerated up to 8mg. Exposure to JNJ26481585 increased proportionally over the 2 to 12mg dose range, with a constant metabolite/parent ratio (3.5 for Cmax; 7 for AUC). Two partial responses (PR) and one stable disease (SD) have been observed. PR occurred in 2 pts with metastatic melanoma treated at 12mg : one pt had a PR in visceral and complete response in subcutaneous melanoma metastases after 22 days of drug and has ongoing response 5 months after stopping treatment; the second pt had PR in lymph nodes and reduction of cutaneous lesions of melanoma. One non small cell lung cancer pt treated at 4mg showed SD for 9 cycles. Assessment of histone acetylation as a pharmacodynamic biomarker in peripheral blood lymphocytes and hair follicles is ongoing. Conclusions: JNJ26481585 is generally well tolerated at doses up to 8mg daily. Evidence of promising antitumor activity has been observed with 2 PR to date in patients with metastatic melanoma. The 8mg cohort is being expanded with increased cardiac monitoring. Other schedules may be explored in the future.

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[Role of cannabinoid receptors in regulation of cardiac tolerance to ischemia and reperfusion]

Coronary artery occlusion (45 min) and reperfusion (2 h) were modeled in vivo in anesthetized artificially ventilated Wistar rats. Total ischemia (45 min) and reperfusion (30 min) of the isolated rat heart were performed in vitro. The selective agonist of cannabinoid (CB) receptors HU-210 was injected intravenously at a dose of 0.1 mg/kg 15 min prior to the coronary artery ligation. The selective CB1 antagonist SR141716A and the selective CB2 antagonist SR144528 were injected intravenously 25 min prior to ischemia. In vitro, HU-210 and SR141716A were added to the perfusion solution at the final concentrations of 0.1 microM prior to total ischemia. Preliminary injection of HU-210 reduced the infarct size-to-area at risk (IS/AAR) ratio in vivo. This cardioprotective effect was completely abolished by SR141716A but remained after SR144528 injection. Both antagonists had no effect on the IS/AAR ratio. Preliminary injection of the K(ATP) channel blocker glibenclamide did not abolish the cardioprotective effect of HU-210. The addition of HU-210 prior to ischemia reduced the creatine phosphokinase (CPK) level in the coronary effluent and decreased left ventricular developed pressure. SR141716A alone had no effect on cardiac contractility and CPK levels. These results suggest that cardiac CB1 receptor activation increases cardiac tolerance to ischemia-reperfusion and has a negative effect on the cardiac pump function. Endogenous cannabinoids are not involved in the regulation of cardiac contractility and tolerance to ischemia and reperfusion. ATP-sensitive E+ channels are not involved in the mechanism of the cardioprotective effect of HU-210.

Socioeconomic variations in women's diets: what is the role of perceptions of the local food environment?

OBJECTIVES

To test the contribution of perceived environmental factors (food availability, accessibility and affordability) to mediating socioeconomic variations in women's fruit, vegetable and fast food consumption.

METHODS

A community sample of 1580 women from 45 neighbourhoods provided survey data on their socioeconomic position (SEP) (education and income); diet (fruit, vegetable and fast food consumption); and the perceived availability of, access to and cost of healthy food in their local area.

RESULTS

Once perceived environmental variables were considered, the associations between SEP and diet were weak and non-significant, suggesting that socioeconomic differences in diet were almost wholly explained by perceptions of food availability, accessibility and affordability.

CONCLUSIONS

Strategies to decrease socioeconomic inequalities in diet could involve promoting inexpensive ways to increase fruit and vegetable consumption, and ensuring that people of low SEP are aware that many healthy foods are available at relatively low cost. Future research should also confirm if perceptions match objective measures of food availability, accessibility and affordability, in order to address the real and/or perceived lack of healthy options in low SEP neighbourhoods.

Comparison of [3H]-(2S,4R)-4-methylglutamate and [3H]d-aspartate as ligands for binding and autoradiographic analyses of glutamate transporters

While studies with [(3)H]D-aspartate ([(3)H]d-Asp) illustrate specific interactions with excitatory amino acid transporters (EAATs), new insights into the pharmacological characteristics and localization of specific EAAT subtypes depend upon the availability of novel ligands. One such ligand is [(3)H]-(2S,4R)-4-methylglutamate ([(3)H]4MG) which labels astrocytic EAATs in homogenate binding studies. This study examined the utility of [(3)H]4MG for binding and autoradiography in coronal sections of rat brain. Binding of [(3)H]4MG was optimal in 5mM HEPES buffer containing 96 mM NaCl, pH 7.5. Specific binding of [(3)H]4MG exhibited two components, but was to a single site when glutamate receptor (GluR) sites were masked with kainate (KA; 1 microM): t(1/2) approximately 5 min, K(d) 250 nM and B(max) 5.4 pmol/mg protein. Pharmacological studies revealed that [(3)H]4MG, unlike [(3)H]d-Asp, labeled both EAAT and ionotropic GluR sites. Further studies employed 6-cyano-7-nitroquinoxaline (30 microM) to block GluR sites, but selective EAAT ligands displayed lower potency than expected for binding to transporters relative to drugs possessing mixed transporter/receptor activities. Autoradiography in conjunction with densitometry with [(3)H]4MG and [(3)H]d-Asp revealed wide, but discrete distributions in forebrain; significant differences in binding levels were found in hippocampus, nucleus accumbens and cortical sub-areas. Although EAAT1 and EAAT2 components were detectable using 3-methylglutamate and serine-O-sulphate, respectively, the majority of [(3)H]4MG binding was to KA-related sites. Overall, in tissue sections [(3)H]4MG proved unsuitable for studying the autoradiographic localization of EAATs apparently due to its inability to selectively discriminate Na(+)-dependent binding to Glu transporters.