Search tips
Search criteria

Results 1-12 (12)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Validity of actigraphs uniaxial and triaxial accelerometers for assessment of physical activity in adults in laboratory conditions 
BMC Medical Physics  2013;13:5.
Few studies to date have directly compared the Actigraphs GT1M and the GT3X, it would be of tremendous value to know if these accelerometers give similar information about intensities of PA. Knowing if output is similar would have implications for cross-examination of studies. The purpose of the study was to assess the validity of the GT1M and the GT3X Actigraph accelerometers for the assessment of physical activity against oxygen consumption in laboratory conditions.
Forty-two college-aged participants aged 18-25 years wore the GT1M and the GT3X on their right hip during treadmill exercise at three different speeds, slow walking 4.8 km.h-1, fast walking 6.4 km.h-1, and running 9.7 km.h-1). Oxygen consumption was measured minute-by minute using a metabolic system. Bland-Altman plots were used to assess agreement between activity counts from the GT3X and GT1M, and correlations were assessed the ability of the accelerometers to assess physical activity.
Bias for 4.8 km.h-1 was 2814.4 cpm (limits 1211.3 to 4417.4), for 6.4 km.h-1 was 3713.6 cpm (limits 1573.2 to 5854.0), and for 9.7 km.h-1 was−3811.2 cpm (limits 842.1 to 6780.3). Correlations between counts per minute for the GT1M and the GT3X were significantly correlated with VO2 (r = 0.881, p < 0.001; r = 0.810, p < 0.001 respectively).
The present study showed that both the GT1M and the GT3X accurately measure physical activity when compared to oxygen consumption.
PMCID: PMC4175111  PMID: 24279826
Actigraph; Triaxial; Accelerometers; Young adults; Validation
2.  Randomized Controlled Trial to Improve Adiposity, Inflammation, and Insulin Resistance in Obese African-American and Latino Youth 
Obesity (Silver Spring, Md.)  2011;20(4):811-818.
The purpose of this study was to examine ethnic differences in the metabolic responses to a 16-week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African-American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre- and postintervention: strength, dietary intake, body composition (dual-energy X-ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. −32.3% vs. −6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. −14.2% vs. −13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: −27.3% vs. −4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor-1 (PAI-1) (−38.3% vs. +1.0%, P < 0.01) and resistin (−18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2-h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (P’s < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.
PMCID: PMC3106142  PMID: 21293446
3.  Pubertal Changes of Insulin Sensitivity, Acute Insulin Response and β-Cell function in Overweight Latino Youth 
The Journal of pediatrics  2011;158(3):442-446.
To examine changes in insulin sensitivity (SI), compensatory acute insulin response (AIR) and β-cell function/disposition index (DI) across puberty in overweight Latino boys and girls.
Study design
253 Latino children followed annually for up to 5 years. Longitudinal modeling was used to examine changes in SI, AIR, DI and fasting and 2-hr glucose and insulin across Tanner stage.
In boys, SI decreased in early puberty with a recovery by late puberty. The compensatory increase in AIR was appropriate in early maturation, but after Tanner 3, AIR declined by more than that predicted from the recovery in SI. For girls, SI decreased in early puberty and across all stages of maturation. In early maturation, there was an appropriate compensatory increase in AIR, but after Tanner 3 AIR decreased. Thus, DI deteriorated across puberty in boys and girls.
In overweight Hispanic youth, compensatory changes in insulin secretion fails after Tanner 3 in both sexes, indicating β-cell deterioration during this critical period of development, thus increasing risk for Type 2 diabetes.
PMCID: PMC3039101  PMID: 20888012
Insulin resistance; Beta cell function; puberty; longitudinal; Latino
4.  Increased physical activity and reduced adiposity in overweight Hispanic adolescents 
Objectives of this study were to examine 1) whether changes in total PA (counts/minute, cpm) and time spent in moderate to vigorous PA (MVPA) are associated with changes in adiposity and 2) whether energy intake influences the relationship between changes in PA and changes in adiposity in overweight Hispanic adolescents.
Analysis included 38 overweight (BMI ≥ 85th %ile) Hispanic adolescents with complete pre- and post-test data on relevant variables after participating in a 16-week intervention. The intervention treatment did not influence physical activity, so the sample was combined and randomization group was adjusted for in the analysis. Body composition by DEXA, 7-day physical activity by accelerometry, and dietary intake by 3-day diet records were assessed pre- and post-intervention.
Within individuals, the mean increase of PA (n=19) and mean decrease of PA (n=19) was approximately 105 cpm. A 100 cpm increase in total PA was associated with a decrease of 1.3 kg fat mass and 0.8% body fat after adjusting for pre-test adiposity, PA, age, sex, and treatment (p < 0.05). Controlling for energy intake modestly strengthened the relationships between total PA and fat mass and percent body fat. Changes in MVPA were not related to changes in adiposity after controlling for total PA (p>0.05).
Increasing total PA by 28% (100 cpm) was associated with a decrease of 1.4 kg of fat mass and 1% body fat over 16 weeks in overweight Hispanic adolescents independent of intervention group assignment. Increases in total physical activity, as compared to MVPA, may be sufficient to improve body composition in overweight Hispanic adolescents.
PMCID: PMC3163456  PMID: 19952807
Obesity; children; Hispanic; accelerometer; youth; DEXA
6.  Dietary Intake and the Metabolic Syndrome in Overweight Latino Children 
Little is known about the relationship between diet and metabolic health in Latino children, a population at increased risk for diabetes. The present study evaluates diet composition and the metabolic syndrome in a cross-sectional sample of 109 overweight Latino children aged 10 to 17 years with a family history of type 2 diabetes. Dietary intake was assessed by two 24-hour recalls. Associations between nutrients and features of the metabolic syndrome were examined using multiple linear regression and analysis of covariance. Log cholesterol intake was positively associated with log systolic blood pressure (β=0.034, P=0.017) and log soluble dietary fiber intake was inversely associated with log waist circumference (β=−0.069, P=0.036). Log soluble fiber intake was significantly higher in participants with 0 features compared to those with 3+ features of the metabolic syndrome (P=0.046), which translates to 5.2 g vs 4.1 g soluble fiber daily. No other significant associations were found between dietary variables and either the individual features of the metabolic syndrome or the clustering of metabolic syndrome components. Increases in soluble fiber through the daily consumption of fruits, vegetables, and beans may improve metabolic health in Latino children.
PMCID: PMC2882193  PMID: 18656576
7.  Randomized Control Trial to Improve Adiposity and Insulin Resistance in Overweight Latino Adolescents 
Obesity (Silver Spring, Md.)  2009;17(8):1542-1548.
Few randomized trials attempt to improve insulin sensitivity and associated metabolic risks in overweight Latino youth. The purpose of this study is to examine the effects of a modified carbohydrate nutrition program combined with strength training on insulin sensitivity, adiposity, and other type 2 diabetes risk factors in overweight Latino adolescents. In a 16-week randomized trial, 54 overweight Latino adolescents (15.5 ± 1.0 years) were randomly assigned to: (i) Control (C; n = 16), (ii) Nutrition (N; n = 21), or (iii) Nutrition + Strength training (N+ST; n = 17). The N group received modified carbohydrate nutrition classes (once per week), while the N+ST received the same nutrition classes plus strength training (twice per week). The following were measured at pre- and postintervention: strength by 1-repetition maximum, dietary intake by 3-day records, body composition by dual-energy X-ray absorptiometry, glucose/insulin indices by oral glucose tolerance test (OGTT) and intravenous glucose tolerance test with minimal modeling. Across intervention group effects were tested using analysis of covariance with post hoc pairwise comparisons. A significant overall intervention effect was found for improvement in bench press (P < 0.001) and reductions in energy (P = 0.05), carbohydrate (P = 0.04) and fat intake (P = 0.03). There were no significant intervention effects on insulin sensitivity, body composition, or most glucose/insulin indices with the exception of glucose incremental area under the curve (IAUC) (P = 0.05), which decreased in the N and N+ST group by 18 and 6.3% compared to a 32% increase in the C group. In conclusion, this intense, culturally tailored intervention resulted in no significant intervention effects on measured risk factors with the exception of a beneficial effect on glycemic response to oral glucose.
PMCID: PMC2846423  PMID: 19247280
8.  Dietary fiber and associations with adiposity and fasting insulin among college students with plausible dietary reports 
We examined the dietary fiber intake, food sources of dietary fiber, and relationship of dietary fiber with body composition and metabolic parameters in college students with plausible dietary reports.
Research Methods & Procedures
Students (18–24 yrs) provided data on anthropometry, fasting blood chemistries, and body composition (bioelectric impedance). Diet and physical activity were assessed with the Diet History Questionnaire and the International Physical Activity Questionnaire. Plausible dietary reporters were identified (± 1 SD cutoffs for reported energy intake as a percentage of predicted energy requirement). Multiple regression analyses were conducted with the total (n=298) and plausible (n=123) samples, adjusting for age, race, sex, smoking status, physical activity, energy intake, and fat free mass (where applicable).
Food sources of dietary fiber were similar in males and females. In the plausible sample compared to the total sample, dietary fiber was more strongly associated with fat mass (β=−0.24, p<0.001), percent body fat (β= −0.23, p<0.001), BMI (β= −0.11, p<0.01), waist circumference (β= −0.67, p<0.05), and fasting insulin (β= −0.15, p<0.001). When the effect of sex was investigated, dietary fiber was inversely related to fasting insulin and fat mass in men and women and inversely related to percent body fat, BMI, and waist circumference in men only (p<0.05).
Inclusion of implausible dietary reports may result in spurious or weakened diet-health associations. Dietary fiber is negatively associated fasting insulin levels in males and females and consistently associated with adiposity measures in males.
PMCID: PMC2831808  PMID: 19403267
Diet; glucose; body composition; adults; health; food habits
9.  Cardiorespiratory fitness predicts changes in adiposity in overweight Hispanic boys 
Obesity (Silver Spring, Md.)  2008;16(5):1072-1077.
We have previously shown that cardiorespiratory fitness predicts increasing fat mass during growth in white and African-American youth, but limited data are available examining this issue in Hispanic youth. Study participants were 160 (53% boys) overweight (BMI ≥ 85th percentile for age and gender) Hispanic children (mean ± SD age at baseline =11.2 ± 1.7 yrs). Cardiorespiratory fitness, or VO2max, was measured via a maximal effort treadmill test at baseline. Body composition by dual-energy x-ray absorptiometry and Tanner stage by clinical exam were measured at baseline and annually thereafter for up to four years. Linear mixed models were used to examine the gender specific relationship between VO2max and increases in adiposity (change in fat mass independent of change in lean tissue mass) over four years. The analysis was adjusted for changes in Tanner stage, age, and lean tissue mass. In boys, higher VO2max at baseline was inversely associated with the rate of increase in adiposity (β= -0.001, p=0.03); this effect translates to a 15% higher VO2max at baseline resulting in a 1.38kg lower fat mass gain over four years. However, VO2max was not significantly associated with changes in fat mass in girls (β=0.0002, p=0.31). In overweight Hispanic boys, greater cardiorespiratory fitness at baseline was protective against increasing adiposity. In girls however, initial cardiorespiratory fitness was not significantly associated with longitudinal changes in adiposity. These results suggest that fitness may be an important determinant of changes in adiposity in overweight Hispanic boys but not in girls.
PMCID: PMC2780237  PMID: 18309303
Children; Youth; Longitudinal; Gender
10.  Development of Macrophages with Altered Actin Organization in the Absence of MafB 
Molecular and Cellular Biology  2006;26(18):6808-6818.
In the hematopoietic system the bZip transcription factor MafB is selectively expressed at high levels in monocytes and macrophages and promotes macrophage differentiation in myeloid progenitors, whereas a dominant-negative allele can inhibit this process. To analyze the requirement of MafB for macrophage development, we generated MafB-deficient mice and, due to their neonatal lethal phenotype, analyzed macrophage differentiation in vitro, in the embryo, and in reconstituted mice. Surprisingly we observed in vitro differentiation of macrophages from E14.5 fetal liver (FL) cells and E18.5 splenocytes. Furthermore we found normal numbers of F4/80+/Mac-1+ macrophages and monocytes in fetal liver, spleen, and blood as well as in bone marrow, spleen, and peritoneum of adult MafB−/− FL reconstituted mice. MafB−/− macrophages showed intact basic macrophage functions such as phagocytosis of latex beads or Listeria monocytogenes and nitric oxide production in response to lipopolysaccharide. By contrast, MafB−/− macrophages expressed increased levels of multiple genes involved in actin organization. Consistent with this, phalloidin staining revealed an altered morphology involving increased numbers of branched protrusions of MafB−/− macrophages in response to macrophage colony-stimulating factor. Together these data point to an unexpected redundancy of MafB function in macrophage differentiation and a previously unknown role in actin-dependent macrophage morphology.
PMCID: PMC1592864  PMID: 16943423
11.  Physical activity to prevent obesity in young children: cluster randomised controlled trial 
BMJ : British Medical Journal  2006;333(7577):1041.
Objective To assess whether a physical activity intervention reduces body mass index in young children.
Design Cluster randomised controlled single blinded trial over 12 months.
Setting Thirty six nurseries in Glasgow, Scotland.
Participants 545 children in their preschool year, mean age 4.2 years (SD 0.2) at baseline.
Intervention Enhanced physical activity programme in nursery (three 30 minute sessions a week over 24 weeks) plus home based health education aimed at increasing physical activity through play and reducing sedentary behaviour.
Main outcome measure Body mass index, expressed as a standard deviation score relative to UK 1990 reference data. Secondary measures were objectively measured physical activity and sedentary behaviour; fundamental movement skills; and evaluation of the process.
Results Group allocation had no significant effect on the primary outcome measure at six and 12 months or on measures of physical activity and sedentary behaviour by accelerometry. Children in the intervention group had significantly higher performance in movement skills tests than control children at six month follow-up (P=0.0027; 95% confidence interval 0.3 to 1.3) after adjustment for sex and baseline performance.
Conclusions Physical activity can significantly improve motor skills but did not reduce body mass index in young children in this trial.
Trial registration Current Controlled Trials ISRCTN36363490.
PMCID: PMC1647320  PMID: 17028105
12.  Toe-to-finger transfer for post-traumatic reconstruction of the fingerless hand 
Canadian Journal of Surgery  2001;44(4):275-283.
To assess the utility of toe-to-finger transfers (TFTs) for post-traumatic reconstruction of the fingerless hand.
A case series.
A regional trauma centre.
Eight men, mean age was 36 years (range from 25–59 yr), who had lost all the fingers from a hand due to a crush–degloving injury (6 patients), frostbite (1 patient) or a burn injury (1 patient).
TFT. Twelve TFTs were cone and the mean time from injury to reconstruction was 17.2 months.
Main outcome measures
Objective (range of motion, moving 2-point discrimination, grip strength, key pinch, Jebsen–Taylor hand assessment, return to work) and subjective (activities of daily living and a questionnaire) measures.
Eleven of the 12 transfers survived. Six of the 7 in whom the transfer was successful were available for follow-up (mean 45 mo). Range of motion was 10° at the distal interphalangeal joint, 18° at the proximal interphalangeal joint and 59° at the metacarpophalangeal joint. Sensation was protective in all. Grip strength and key pinch were 26.1% and 70.2% of the contralateral hand respectively. Jebsen–Taylor assessment indicated that basic activities were possible but slowed. All 6 patients returned to work and could perform 92.6% of the activities of daily living unassisted. Hand and foot symptoms were mild. Two-thirds were appearance conscious, 5 of the 6 went on to altered vocations and all reported overall satisfaction as high.
This study supports TFT for reconstruction of the fingerless hand in that, although transferred toe function may be poorer than a normal finger, the hand is restored to a useful, sensate and versatile functional unit, such that global hand and patient function, as well as patient satisfaction, are very good.
PMCID: PMC3692660  PMID: 11504261

Results 1-12 (12)