Lifelong physical activity in maintaining bone strength in older men and women of the Age, Gene/Environment Susceptibility-Reykjavik Study.

UNLABELLED: We examined if lifelong physical activity is important for maintaining bone strength in the elderly. Associations of quantitative computerized tomography-acquired bone measures (vertebral and femoral) and self-reported physical activity in mid-life (mean age, 50 years), in old age (≥65 years), and throughout life (recalled during old age) were investigated in 2,110 men and 2,682 women in the AGES-Reykjavik Study. Results conclude lifelong physical activity with continuation into old age (≥65 years) best maintains better bone health later in life. INTRODUCTION: Skeletal loading is thought to modulate the loss of bone in later life, and physical activity is a chief means of affecting bone strength by skeletal loading. Despite much discussion regarding lifelong versus early adulthood physical activity for preventing bone loss later in life, inconsistency still exists regarding how to maintain bone mass later in life (≥65 years). METHODS: We examined if lifelong physical activity is important for maintaining bone strength in the elderly. RESULTS: The associations of quantitative computerized tomography-acquired vertebral and femoral bone measures and self-reported physical activity in mid-life (mean age, 50 years), in old age (≥65 years), and throughout life (recalled during old age) were investigated in 2,110 men and 2,682 women in the AGES-Reykjavik Study. CONCLUSION: Our findings conclude that lifelong physical activity with continuation into old age (≥65 years) best maintains better bone health in the elderly.

Refined food addiction: a classic substance use disorder.

Overeating in industrial societies is a significant problem, linked to an increasing incidence of overweight and obesity, and the resultant adverse health consequences. We advance the hypothesis that a possible explanation for overeating is that processed foods with high concentrations of sugar and other refined sweeteners, refined carbohydrates, fat, salt, and caffeine are addictive substances. Therefore, many people lose control over their ability to regulate their consumption of such foods. The loss of control over these foods could account for the global epidemic of obesity and other metabolic disorders. We assert that overeating can be described as an addiction to refined foods that conforms to the DSM-IV criteria for substance use disorders. To examine the hypothesis, we relied on experience with self-identified refined foods addicts, as well as critical reading of the literature on obesity, eating behavior, and drug addiction. Reports by self-identified food addicts illustrate behaviors that conform to the 7 DSM-IV criteria for substance use disorders. The literature also supports use of the DSM-IV criteria to describe overeating as a substance use disorder. The observational and empirical data strengthen the hypothesis that certain refined food consumption behaviors meet the criteria for substance use disorders, not unlike tobacco and alcohol. This hypothesis could lead to a new diagnostic category, as well as therapeutic approaches to changing overeating behaviors.

Phenolic compounds from the flowers of Garcinia dulcis.

Dulcisxanthones C-F and dulcinone together with 22 known compounds were isolated from the flowers of Garcinia dulcis. Their structures were determined by spectroscopic methods. The abilities of some of these compounds to act as radical scavengers and antibacterial agents were investigated.

Xanthone derivatives from Cratoxylum cochinchinense roots.

Two xanthones and two caged-prenylated xanthones, named cochinchinones A-D, respectively, and a synthetically known caged-prenylated xanthone, together with seven known compounds were isolated from the roots of Cratoxylum cochinchinense (Lour.) Blume. Their structures were assigned on the basis of analyses of spectroscopic data. Some of the compounds exhibited effective antioxidative properties.

Phenolic compounds from the fruit of Garcinia dulcis.

Dulcinoside (1), dulcisisoflavone (2), dulcisxanthone A (3) and sphaerobioside acetate (6) together with 22 known compounds were isolated from the green fruit of G. dulcis. Dulcisflavan (4), dulcisxanthone B (5) and isonormangostin (7) together with 22 known compounds were isolated from the ripe fruit. Compounds 6 and 7 were synthetic known compounds. Their structures were determined by spectroscopic methods. The radical scavenging and antibacterial activities of some of the compounds were investigated.

Xanthones from Garcinia cowa Roxb. latex.

Five xanthones named cowagarcinone A-E and six previously reported xanthones were isolated from the latex of Garcinia cowa Roxb. Their structures were determined on the basis of spectroscopic analysis. The crude latex and the isolated compounds were investigated for their radical scavenging activities.

A benzil and isoflavone derivatives from Derris scandens Benth.

A benzil derivative: scandione, 2',2"-dihydroxy-4'-methoxy-4",5"-methylenedioxybenzil and two isoflavones: scandenal, 3'-formyl-4',5-dihydroxy-2",2"-dimethylchromeno-[6,7:5",6"]isoflavone and scanderone, 4',5-dihydroxy-3'-prenyl-2",2"-dimethylchromeno-[7,8:6",5"]isoflavone together with fifteen known compounds were isolated from the stem of D. scandens. Their structures were determined by spectroscopic methods. Radical scavenging, antibacterial and hypertensive activities of some of the compounds were investigated.

Quantitative regulation of the Flaveria Me1 gene is controlled by the 3'-untranslated region and sequences near the amino terminus.

The Me1 gene of Flaveria bidentis codes for the C4 isoform of NADP malic enzyme, which accumulates to a high-level only in bundle sheath cells. Previous experiments demonstrated that sequences at the 5' end of the gene control cell specificity whereas sequences at the 3' end are necessary for high-level expression. To localize quantitative regulator sequences, we have analysed a series of Me1 3' deletion constructs fused to the gusA reporter gene. We show that sequences within the 3'-untranslated region (3'-UTR) control quantitative levels of expression. Analysis of 5' promoter fusions demonstrated that high-level expression also requires sequences within the N-terminal coding region of the gene, suggesting possible interactions between the 3'-UTR and 5' coding regions. Cell-specific regulatory sequences are located in a different part of the 5' end of the gene, between 1023 bp upstream of the transcription start and the start of translation.

The 3' non-coding region of a C4 photosynthesis gene increases transgene expression when combined with heterologous promoters.

The Me1 gene of the dicot Flaveria bidentis encodes NADP malic enzyme, which catalyses the decarboxylation reaction of C4 photosynthesis in bundle sheath cells. We have previously shown that the 3' non-coding region (Me1 3') controls quantitative expression of the gene. We wondered whether Me1 3' can increase expression when combined with heterologous promoters. We tested a highly expressed, constitutive promoter, the S4 promoter from subterranean clover stunt virus, and a highly expressed, leaf-specific promoter, the light-harvesting chlorophyll a/b-binding protein gene 3 (Lhcb3) promoter of Arabidopsis thaliana. Promoter-3'-end combinations were tested in transgenic C4 Flaveria plants and C3 tobacco. We found that Me1 3' increased expression of the gusA reporter gene several-fold in leaves of both species in combination with either of the promoters. In both cases Me1 3' does not alter the expression pattern for either promoter. We conclude that Me1 3' can be used as a transcription terminator to increase transgene expression in C3 dicot plants.

New rearranged clerodane diterpenes from Tinospora baenzigeri.

Baenzigeroside B, a new rearranged clerodane diterpene glucoside, was isolated from the stems of Tinospora baenzigeri. The aglycone of baenzigeroside B, baenzigeride B (isolated as its acetate), was found together with baenzigeride A, baenzigerosides A and B in the leaves of the same plant. Baenzigeride B and baenzigeroside B are the first examples of a new class of rearranged clerodane diterpenes. The possible biogenesis of the compounds is discussed.

A new cyclobutane lignan from Cinnamomum balansae.

A new cyclobutane lignan, named cinbalansan (6), was isolated from the leaves of Cinnamomum balansae, along with five known compounds, 1,2-dimethoxy-4-(1-E-propenyl)benzene (1), 1,2-dimethoxy-4-(1-Z-propenyl)benzene (2), 1,2-dimethoxy-4-(2-propenyl)benzene (3), 3,4-dimethoxybenzaldehyde (4), and E-(3,4-dimethoxyphenyl)-2-propenal (5). The structure of cinbalansan was shown to be 1beta,2beta,3alpha,4alpha-1,2-dimethyl-3,4-bis(3,4-dimethoxyphenyl)cyclobutane by a combination of 1H-, 13C-NMR, and NOE- experiments and by direct analysis of the 1H-NMR spectrum by the method of X-application.

Lanostanes and friedolanostanes from the pericarp of Garcinia hombroniana.

The CH2Cl2 extract from the pericarp of Garcinia hombroniana yielded three 17,14-friedolanostanes [(24E)-3alpha-hydroxy-17,14-friedolanostan-8, 14,24-trien-26-oic acid, methyl (24E)-3alpha,23-dihydroxy-17,14-friedolanostan-8,14,24 -trien-26-oate and methyl (24E)-3alpha,9,23-trihydroxy-17,14-friedolanostan-14,2 4-dien-26-oate] and two lanostanes [3beta- and 3alpha-hydroxy-23-oxo-9,16-lanostadien-26-oic acid]. The structure of (14E)-3alpha-hydroxy-17,14-friedolanostan-8,14,24-trie n-26-oic acid was determined using spectroscopic and X-ray analyses, while the structures of the other compounds were elucidated solely from analysis of spectroscopic data.

A review of correlates of physical activity of children and adolescents.

BACKGROUND: Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results. METHODS: A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3-12) and adolescents (ages 13-18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents. RESULTS: About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children's physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents' physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise. CONCLUSION: These consistently related variables should be confirmed in prospective studies, and interventions to improve the modifiable variables should be developed and evaluated.

Using objective physical activity measures with youth: how many days of monitoring are needed?

PURPOSE: The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. METHODS: A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). RESULTS: Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analyses indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). CONCLUSIONS: These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.

Correlates of physical activity in a national sample of girls and boys in grades 4 through 12.

Psychological, biological, social, and physical environmental variables were examined for their association with physical activity of young people. A national sample of 1,504 parents and children in Grades 4-12 were interviewed by telephone. Twenty-two potential determinants were assessed along with an 11-item child physical activity index (alpha = .76). Hierarchical multiple regressions were conducted separately for 6 age-sex subgroups. Percentage of variance explained ranged from 18% for boys in Grades 4-6 to 59% for girls in Grades 10-12. Three variables had strong and consistent associations with the child physical activity index that generalized across subgroups: use of afternoon time for sports and physical activity, enjoyment of physical education, and family support for physical activity. These 3 variables should be targeted for change to promote physical activity in all groups of young people.

Childhood and adolescent physical activity patterns and adult physical activity.

PURPOSE: A major research priority is the influence of childhood and adolescent physical activity patterns on adult physical activity. The research in this area is inconsistent. Therefore, the purpose of this study was to evaluate the relationships among specific components of physical activity during childhood and adolescence and exercise habits in adulthood. METHODS: We analyzed preteen and teenage experiences, individual and team sports, and several psychosocial variables. One hundred and five male volunteers completed questionnaires about their current (estimated energy expenditure (EE)) and historic physical activity and a treadmill stress test. RESULTS: Based on correlations and regression analyses, without and with controlling for potentially confounding variables (treadmill run time and sum of skinfolds), the frequency of being forced to exercise and the frequency of being encouraged to exercise during the preteen years were inversely related to adult physical activity. Being forced to exercise during the preteen years was more related to participation in individual sports than to participation in team sports or both individual and team sports. CONCLUSIONS: Being forced to exercise during childhood may have potentially negative consequences for later activity. The findings indicate that experiences related to participation in activity during childhood and adolescence may influence adult physical activity. The implications of our findings are discussed and future research is recommended.

Physical activity among African American and Latino middle school girls: consistent beliefs, expectations, and experiences across two sites.

Physical inactivity is a major public health concern. Low levels of physical activity are reported in many subgroups of women including adolescent girls. More data are needed to better understand factors related to physical activity participation in adolescent girls. Therefore, we explored adolescent girls' reasons for participating and not participating in physical activity. Two independent samples were taken in California and Texas; the total sample included thirty-four African American and Latino girls. Six focus groups were conducted by trained facilitators. Based on independent qualitative analyses, six replicated themes emerged from the focus groups. Fun, social support, and concern with body image facilitated participation in activity. In contrast, negative experiences in physical education classes, concerns about appearance after activity, and lack of opportunity impeded participation in activity. Overall, the girls showed an interest in physical activity and identified activity motivators and barriers. We discuss the implications of our findings for future research.

Physical activity interventions in low-income, ethnic minority, and populations with disability.

BACKGROUND: Low-income, racial and ethnic minority, and populations with disabilities are more likely to be sedentary than the general population. Increasing physical activity in these groups is an important public health challenge. This report summarizes interventions that have targeted populations at risk for inactivity. METHODS: Computer and manual searches were performed to identify manuscripts published from 1983 to 1997. Interventions conducted in these populations in which physical activity was part of the intervention, and activity or cardiorespiratory fitness were outcome measures, were included in the review. RESULTS: Fourteen studies were identified. Most studies used pre-post or quasi-experimental designs. Common intervention features for the ten studies that included ethnic minority groups were community advisory panels, community needs assessments, and community members delivering the intervention. Eight studies reported a theoretical framework that guided the intervention. Increased physical activity was documented in two studies. Post-intervention follow-up was conducted in two studies; both reported no significant findings. Only four studies for people with disabilities were found; all four reported post-intervention physical activity change. CONCLUSION: Much work remains to develop effective interventions for these populations. Research that involves the community at all steps in the design and implementation of the intervention shows greatest promise for promoting behavior change. Future intervention studies should include: (1) rigorous experimental designs; (2) theoretically based interventions; and (3) validated assessment instruments to detect physical activity change.

Cigarette smoking in a multiethnic population of youth: methods and baseline findings.

BACKGROUND: To expand upon recent research studies that have identified dramatic ethnic differences in adolescent cigarette smoking, this study was designed to characterize smoking among a multiethnic population of adolescents and to identify significant factors that may protect against smoking initiation. METHODS: During the first 2 years, this mixed cross-sectional, longitudinal study recruited and collected baseline data from a volunteer sample of 1,441 Houston-area public school students in the 5th, 8th, or 12th grade. A wide range of new and established predictors of smoking behavior was assessed, and their associations with ever smoking and susceptibility to smoking were assessed within ethnicity (white, N = 537; African-American, N = 454; and Hispanic, N = 297). RESULTS: Consistent with previous studies, white students smoked in substantially higher proportions than African-American students, with Hispanic adolescents in-between. Simultaneously adjusting for other variables, the odds of ever smoking (OR = 0.47, P < 0.01) and susceptibility to smoking (OR = 0.64, P < 0.01) were significantly lower among African-American adolescents when compared with whites; odds ratios for Hispanics and whites did not differ. Across all three ethnicities, the most important predictor of both ever smoking and susceptibility to smoking was the smoking status of the three best friends. Several ethnicity-specific variables also were identified. CONCLUSIONS: In concordance with previous investigations, cigarette smoking prevalence differs by ethnicity, and the factors associated with ever smoking and susceptibility to smoking differ among white, African-American, and Hispanic adolescents. The results of this study may be used to develop theory-based, culturally appropriate smoking intervention programs for adolescents.