Metabolites as novel biomarkers for childhood obesity-related traits in Mexican-American children.

BACKGROUND/OBJECTIVES: Although newer approaches have identified several metabolites associated with obesity, there is paucity of such information in paediatric populations, especially among Mexican-Americans (MAs) who are at high risk of obesity. Therefore, we performed a global serum metabolite screening in MA children to identify biomarkers of childhood obesity. METHODS: We selected 15 normal-weight, 13 overweight and 14 obese MA children (6-17 years) and performed global serum metabolite screening using ultra-performance liquid chromatography/quadruple orthogonal acceleration time of flight tandem micro mass spectrometer. Metabolite values were analysed to assess mean differences among groups using one-way analysis of variance, to test for linear trend across groups and to examine Pearson's correlations between them and seven cardiometabolic traits (CMTs): body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, homeostasis model of assessment-insulin resistance, triglycerides and high-density lipoprotein cholesterol. RESULTS: We identified 14 metabolites exhibiting differences between groups as well as linear trend across groups with nominal statistical significance. After adjustment for multiple testing, mean differences and linear trends across groups remained significant (P < 5.9 × 10(-5) ) for L-thyronine, bradykinin and naringenin. Of the examined metabolite-CMT trait pairs, all metabolites except for 2-methylbutyroylcarnitine were nominally associated with two or more CMTs, some exhibiting significance even after accounting for multiple testing (P < 3.6 × 10(-3) ). CONCLUSIONS: To our knowledge, this study - albeit pilot in nature - is the first study to identify these metabolites as novel biomarkers of childhood obesity and its correlates. These findings signify the need for future systematic investigations of metabolic pathways underlying childhood obesity.

Predicting the development of the metabolically healthy obese phenotype.

OBJECTIVE: The metabolically healthy (MHO) and unhealthy obese (MUHO) differ in terms of cardiovascular risk. However, little is known about predicting the development of these phenotypes and the future stability of the MHO phenotype. Therefore, we examined these two issues in the San Antonio Heart Study. DESIGN: Longitudinal, population-based study of cardiometabolic risk factors among Mexican Americans and non-Hispanic whites in San Antonio. SUBJECTS: The study sample included 2368 participants with neither MUHO nor diabetes at baseline. Median follow-up was 7.8 years. MHO was defined as obesity with ⩽1 metabolic abnormality; MUHO, as obesity with ⩾2 abnormalities. RESULTS: At baseline, 1595 and 498 individuals were non-obese with ⩽1 and ⩾2 metabolic abnormalities, respectively, and 275 were MHO. Among non-obese individuals, independent predictors of incident MHO (odds ratio (OR) for 1 s.d. change (95% confidence interval)) included body mass index (8.12 (5.66-11.7)), triglycerides (0.52 (0.39-0.68)) and high-density lipoprotein cholesterol (HDL-C) (1.41 (1.11-1.81)), whereas independent predictors of incident MUHO included body mass index (5.97 (4.58-7.77)) and triglycerides (1.26 (1.05-1.51)). Among participants with ⩽1 metabolic abnormality, obesity was associated with greater odds of developing multiple metabolic abnormalities (OR 2.26 (1.74-2.95)). CONCLUSIONS: Triglycerides and HDL-C may be useful for predicting progression to MHO. MHO may not be a stable condition, because it confers an increased risk of developing multiple metabolic abnormalities.

Localization of a major susceptibility locus influencing preterm birth.

Preterm birth (PTB) is a complex trait, but little is known regarding its major genetic determinants. The objective of this study is to localize genes that influence susceptibility to PTB in Mexican Americans (MAs), a minority population in the USA, using predominantly microfilmed birth certificate-based data obtained from the San Antonio Family Birth Weight Study. Only 1302 singleton births from 288 families with information on PTB and significant covariates were considered for genetic analysis. PTB is defined as a childbirth that occurs at <37 completed weeks of gestation, and the prevalence of PTB in this sample was 6.4%. An ∼10 cM genetic map was used to conduct a genome-wide linkage analysis using the program SOLAR. The heritability of PTB was high (h(2) ± SE: 0.75 ± 0.20) and significant (P = 4.5 × 10(-5)), after adjusting for the significant effects of birthweight and birth order. We found significant evidence for linkage of PTB (LOD = 3.6; nominal P = 2.3 × 10(-5); empirical P = 1.0 × 10(-5)) on chromosome 18q between markers D18S1364 and D18S541. Several other chromosomal regions (2q, 9p, 16q and 20q) were also potentially linked with PTB. A strong positional candidate gene in the 18q linked region is SERPINB2 or PAI-2, a member of the plasminogen activator system that is associated with various reproductive processes. In conclusion, to our knowledge, perhaps for the first time in MAs or US populations, we have localized a major susceptibility locus for PTB on chromosome 18q21.33-q23.

Time-dependent contact behavior between diamond and a CNT turf.

The elastic and adhesive properties of nominally vertically aligned carbon nanotube (CNT) turfs have been measured using nanoindentation. The perceived stiffness of a CNT turf is dependent on the unloading rate, which decreases at slower unloading rates. Depth-controlled nanoindentation was used to examine adhesion effects. Adhesive loads between the turf and the probe tip increased as the time the tip is in contact with the turf increased. As these effects could be from either more tubes coming into contact with the tip due to relaxation and motion of CNTs relative to one another or each tube in contact increasing its adhesive behavior and sub-contact stiffness due to tube-tube interactions within the turf, electrical resistance measurements during nanoindentation were carried out. When the tip is held at a fixed nominal depth, the current remains constant while the contact load decreases, suggesting the number of tubes in contact with the tip stays constant with time while the relaxation mechanisms in the turf occur at positions lower than the contact surface. These observations, in conjunction with in situ TEM compression test of CNT arrays, are used to describe the relative effects the various length and time scales may have on the perceived properties measured during experiments, including elastic modulus and adhesion for gecko-like dry adhesives.

Impact of parental smoking on diabetes, hypertension and the metabolic syndrome in adult men and women in the San Antonio Heart Study.

AIMS/HYPOTHESIS: In the San Antonio Heart Study (SAHS) we investigated the effects of exposure to parental smoking on diabetes, hypertension and the metabolic syndrome in adult offspring aged 25-64 years. SUBJECTS, MATERIALS AND METHODS: In a retrospective cohort study the parental smoking status during childhood, obtained through a postal questionnaire, determined a person's exposure status. Logistic regression models were used to calculate odds ratios for diabetes, hypertension and the metabolic syndrome at the baseline SAHS examination in relation to parental smoking status. All models were adjusted for age, sex, ethnicity, education years, personal smoking status (current, former or never-smoker), BMI and, in the case of diabetes, a family history of diabetes. RESULTS: Of the 2,371 participants who returned the mailing, 44.5, 5.4, 20.0 and 30.1% reported that their father, mother, both or neither parent smoked, respectively. Participants reporting that both parents smoked were 1.60 (95% CI: 0.95-2.69) times more likely to have diabetes, 1.55 (95% CI: 1.05-2.28) times more likely to have hypertension, and 1.46 (95% CI: 1.01-2.10) times more likely to have the metabolic syndrome than participants reporting that neither parent smoked during their childhood. Odds ratios, after limiting the population to younger participants (i.e.

Ultrastructural analysis of skeletal muscle development in the fetal pig.

Myogenesis was investigated at the ultrastructural level in the fetal pig at 35, 52, 65, 80, 95 and 110 days of gestation. At each stage of gestation, the predominant type II fiber type portion of the peroneus longus and sartorius muscles was examined. The sequence of events for normal myogenesis in the pig was generally similar to that reported for the skeletal muscle of other vertebrate species. In addition, the time interval for sequential development of myogenesis was similar between the two muscles. Centrioles were identified in primary fetal fibers and also in secondary fibers. No morphological evidence of mitotic activity was found in the myonuclei. The organization of myofibers into fasciculi was unrelated both temporally and spatially to capillary and neural development.

An analysis of skeletal muscle response to selection for rapid growth in Japanese quail (Coturnix coturnix Japonica).

A line of Japanese quail selected for high body weight at 4 weeks of age (P line) was compared to an unselected control (C) line at 10, 23 and 56 days of age. The increase in the weight of the pectoralis major and supracoracoideus muscles in the P line was paralleled by an increase in total DNA, RNA and protein content of the muscles when compared to comparable age C line. DNA, RNA and protein concentrations and RNA/DNA and protein/DNA ratios were similar between lines within age. Greater muscle mass in the P line was accomplished primarily through an increase in the total number of muscle nuclei rather than through an increase in DNA unit size. Ca2+-activated myosin ATPase, total phosphorylase and succinic dehydrogenase enzyme activities were similar between lines and across ages in the pectoralis major and supracoracoideus muscles. The semimembranosus muscle possessed 59% more alpha fibers and only 7% more beta fibers in the P line when compared to the C line. Semimembranosus alpha fiber diameters were not significantly different between lines within age, while beta fiber diameters were significantly greater in the P line. Estimated beta fiber contribution to total semimembranosus muscle cross sectional area revealed no significant difference between lines within age. There was a significant increase in the length of the femur and humerus in the P line when compared to C line within age, indicating that some of the increased muscle weight of the P line quail was due to an increase in muscle length in addition to an increase in muscle cross-sectional area.