Validation and calibration of physical activity monitors in children

OBJECTIVE: This study was designed to validate accelerometer-based activity monitors against energy expenditure (EE) in children; to compare monitor placement sites; to field-test the monitors; and to establish sedentary, light, moderate, and vigorous threshold counts. RESEARCH METHODS AND PROCEDURES: Computer Science and Applications Actigraph (CSA) and Mini-Mitter Actiwatch (MM) monitors, on the hip or lower leg, were validated and calibrated against 6-hour EE measurements by room respiration calorimetry, activity by microwave detector, and heart rate by telemetry in 26 children, 6 to 16 years old. During the 6 hours, the children performed structured activities, including resting metabolic rate (RMR), Nintendo, arts and crafts, aerobic warm-up, Tae Bo, treadmill walking and running, and games. Activity energy expenditure (AEE) computed as EE - RMR was regressed against counts to derive threshold counts. RESULTS: The mean correlations between EE or AEE and counts were slightly higher for MM-hip (r = 0.78 +/- 0.06) and MM-leg (r = 0.80 +/- 0.05) than CSA-hip (r = 0.66 +/- 0.08) and CSA-leg (r = 0.73 +/- 0.07). CSA and MM performed similarly on the hip (inter-instrument r = 0.88) and on the lower leg (inter-instrument r = 0.89). Threshold counts for the CSA-hip were <800, <3200, <8200, and > or = 8200 for sedentary, light, moderate, and vigorous categories, respectively. For the MM-hip, the threshold counts were <100, <900, <2200, and > or = 2200, respectively. DISCUSSION: The validation of the CSA and MM monitors against AEE and their calibration for sedentary, light, moderate, and vigorous thresholds certify these monitors as valid, useful devices for the assessment of physical activity in children.     

Differing Postneonatal Mortality Rates of African-American and White Infants in Chicago: An Ecologic Study

Objectives: This study sought to determine whether neighborhood impoverishment explains the racial disparity in urban postneonatal mortality rates. Methods: Stratified and multivariate logistic regression analyses were performed on the vital records of all African-Americans and whites born in Chicago by means of a linked 1992–1995 computerized birth–death file with appended 1990 U.S. census income and 1995 Chicago Department of Public Health data. Four community-level variables (low median family income, high rates of unemployment, homicide, and lead poisoning) were analyzed. Communities with one or more ecologic risk factors were classified as impoverished. Results: The postneonatal mortality rate of African-Americans (N = 104,656) was 7.5/1000 compared to 2.7/1000 for whites (N = 52,954); relative risk (95% confidence interval) equaled 2.8 (2.3–3.3). Seventy-nine percent of African-American infants compared to 9% of white infants resided in impoverished neighborhoods; p < 0.01. In impoverished neighborhoods, the adjusted odds ratio (controlling for infant and maternal individual-level risk factors) of postneonatal mortality for African-American infants equaled 1.5 (0.5–4.2). In nonimpoverished neighborhoods, the adjusted odds ratio of postneonatal mortality for African-American infants equaled 1.8 (1.1–2.9). Conclusions: We conclude that urban African-American infants who reside in nonimpoverished neighborhoods are at high risk for postneonatal mortality.     

Association of point-of-purchase tobacco advertising and promotions with choice of usual brand among teenage smokers

The objective is to determine the relationship between brand-specific advertising and promotions in convenience stores for Marlboro and Camel cigarettes and choice of usual brand among school students. A cross-sectional survey was designed that merged records of store tobacco advertising and promotions. The survey was administered to 3,890 U.S. high school smokers with a usual brand, matched to 196 convenience stores. Choice of Marlboro as a usual brand was associated with presence of a Marlboro gift with purchase (p <.001) and a greater brand share of interior (p = .05) and exterior (p = .05) advertising voice for Marlboro. Choice of Camel as a usual brand was associated with a greater share of interior advertising voice for Camel (p <.001) but was unrelated to a Camel gift with purchase promotions (p > .05) and negatively associated with a greater share of exterior advertising voice for Camel (p < .001). The results are consistent with the notion that Marlboro-specific advertising and promotions may influence choice of Marlboro as a usual brand to smoke among teens, but resultsfor Camel are mixed and inconclusive. Further research is required to confirm and extend these findings.     

Chronic fatigue syndrome: probable pathogenesis and possible treatments

Chronic fatigue syndrome (CFS) belongs in the medically unexplained illnesses. It affects approximately 0.2-0.7% of the population in Western countries. It is characterised by unexplained fatigue, lasting 6 months or more, impairment of neurocognitive functions and quality of sleep, and of somatic symptoms, such as recurrent sore throat, muscle aches, arthralgias, headache and postexertional malaise. No link between infections and CFS has been clearly established but the immune system is activated, there are aberrations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. No specific treatment has been found. Cognitive behavioural therapy is established to be of value to improve quality of life. More effective treatment should result, as advances in biomedical as well as psychological research continue.     

IL-1 beta signalling in glial cells in wildtype and IL-1RI deficient mice

1. Interleukin-1 (IL-1) has been implicated in neurodegeneration and in central nervous system (CNS)-mediated host defence responses to inflammation. All actions of IL-1 identified to date appear to be mediated through its only known functional type I receptor (IL-1RI). However, our recent evidence suggests that some actions of IL-1 in the brain may be IL-1RI independent, suggesting the involvement of a new, hitherto unknown functional receptor for IL-1. 2. The objective of the present study was to determine if primary mixed glial cells express additional functional IL-1 receptors by studying the signalling mechanisms responsible for the pro-inflammatory actions of IL-1beta in cultures derived from IL-1RI-/- and wildtype mice, and to characterize the functional importance of IL-1 signalling pathways in glia. 3. IL-1beta induced marked release of IL-6 and prostaglandin-E(2) (PGE(2)) in the culture medium, and activated nuclear factor-kappa B (NFkappaB) and the mitogen-activated protein kinases (MAPK) p38, c-Jun N-terminal kinase (JNK) and the extracellular signal-regulated protein kinase (ERK1/2) in cells from wildtype mice. These responses were dependent on IL-1RI, since cells isolated from IL-1R1-/- mice did not demonstrate any of these responses. 4. In wildtype mice, inhibition of p38 or ERK1/2 MAPKs significantly reduced IL-1beta induced IL-6 release, whilst the NFkappaB inhibitor caffeic acid phenethyl ester (CAPE) modulated IL-1 induced IL-6 release by action on NFkappaB and MAPKs pathways. 5. These data demonstrate that IL-1RI is essential for IL-1beta signalling in cultured mixed glial cells. Thus IL-1 actions observed in IL-1RI-/- mice in vivo may occur via an alternative pathway and/or via different CNS cells.     

MK-801- and ethanol-induced activity in inbred long-sleep and short-sleep mice: dopamine and serotonin systems

Low doses of (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801; dizocilpine) or ethanol induce less locomotor activation in inbred long-sleep (ILS) than short-sleep (ISS) mice. These differences may involve altered dopamine and/or 5-hydroxytryptamine (serotonin; 5-HT) neurotransmission. To address this possibility, the dopaminergic and serotonergic mechanisms underlying the locomotor-stimulant effects of MK-801 and ethanol in ILS and ISS mice were studied. Dopamine D1, D2 and 5-HT(2A) receptor antagonists reduced MK-801-stimulated activity in ILS mice without having any effect in ISS mice. The 5-HT reuptake inhibitor fluoxetine potentiated MK-801-stimulated activity selectively in ILS mice. Strain differences in 5-HT transporters do not explain this selective effect of fluoxetine in ILS mice since [3H]citalopram binding and [3H]5-HT uptake studies found no differences in the affinity, number or function of 5-HT transporters between ILS and ISS mice. Ethanol-induced activity in ISS mice was depressed by dopamine D2 and 5-HT(2C) receptor antagonists and enhanced by a 5-HT(1A) receptor antagonist. These results suggest that in ILS mice the locomotor-stimulant effects of MK-801 require increased dopamine and/or 5-HT neurotransmission. Conversely, in ISS mice, the effects of MK-801 appear to be monoamine-independent. Thus, even though both MK-801 and ethanol inhibit N-methyl-D-aspartate receptors, their stimulant effects appear to involve different neuronal systems.     

Gender differences among pathological gamblers seeking treatment

This study investigated gender differences among treatment-seeking pathological gamblers. During treatment intake, 115 pathological gamblers completed the Addiction Severity Index (ASI; A. T. McLellan et al., 1985), including a section on gambling severity, as well as the South Oaks Gambling Screen (H. R. Lesieur & S. B. Blume, 1987). When age and income were controlled, gender differences emerged in ASI gambling, alcohol, and legal scores. Men initiated gambling, began gambling regularly, tried to stop gambling, and first entered gambling treatment at a younger age than women. Women were more likely to be living with someone with a gambling or drinking problem but themselves had fewer alcohol and legal problems. Results suggest that gender differences exist in the initiation of gambling dysfunction and its psychosocial correlates. Understanding these differences may assist in developing treatments that address differential needs of male and female pathological gamblers.