Low-temperature collisional quenching of NO A(2)Σ(+)(v' = 0) by NO(X(2)Π) and O2 between 34 and 109 K.

We present measurements of collisional fluorescence quenching cross sections of NO(A(2)Σ(+), v' = 0) by NO(X(2)Π) and O2 between 34 and 109 K using a pulsed converging-diverging nozzle gas expansion, extending the temperature range of previous measurements. The thermally averaged fluorescence quenching cross sections for both species show a monotonic increase as temperature decreases in this temperature range, consistent with earlier observations. These new measurements, however, allow discrimination between predictions obtained by extrapolating fits of previous data using different functional forms that show discrepancies exceeding 120% for NO and 160% for O2 at 34 K. The measured self-quenching cross section is 52.9 Å(2) near 112 K and increases to 64.1 Å(2) at 35 K, whereas the O2 fluorescence quenching cross section is 42.9 Å(2) at 109 K and increases to 58.3 Å(2) at 34 K. Global fits of the quenching cross section temperature dependence show that, when including our current measurements, the low temperature behavior of the quenching cross sections for NO and O2 is better described by a parameterization that accounts for the long-range interactions leading to the collisional deactivation via an inverse power law model.

Comparison of two waist circumference measurement protocols: the SEARCH for diabetes in youth study.

BACKGROUND: Reports comparing waist circumference (WC) measurements from young populations are scarce. OBJECTIVES: We compared two protocols for measuring waist circumference in a sample of youth with diabetes. METHODS: Participants were enrolled in the SEARCH for Diabetes in Youth Study (SEARCH). WC was measured at least twice by the National Health and Nutrition Examination Survey (NHANES) protocol and twice by the World Health Organization (WHO) protocol. Method-specific averages were used in these analyses. RESULTS: Among 6248 participants, the mean NHANES WC (76.3 cm) was greater than the mean WHO WC (71.9 cm). Discrepancies between protocols were greater for females than males, among older participants, and in those with higher body mass index (BMI). In both sexes and four age strata, the WCs using either method were highly correlated with BMI z-score. The within-method differences between the first and second measurements were similar for the two methods. CONCLUSIONS: These analyses do not provide evidence that one of these two methods is more reproducible or is a better indicator of obesity as defined by BMI z-scores.

Association of insulin sensitivity to lipids across the lifespan in people with Type 1 diabetes.

AIMS: Insulin resistance and dyslipidaemia both increase cardiovascular risk in Type 1 diabetes. However, little data exist on the associations of insulin resistance to lipids in Type 1 diabetes. Our objective was to explore the associations between insulin resistance (assessed by glucose infusion rate) and lipids in people with Type 1 diabetes and determine whether adiposity and/or average glycaemia influence these associations. METHODS: Hyperinsulinaemic-euglycaemic clamp studies were performed in 60 subjects with Type 1 diabetes aged 12-19 years (age 15±2 years, 57% female, duration of diabetes 6.3±3.8 years, HbA(1c) 8.6±1.5%, IFCC=70 mmol/mol) and 40 subjects with Type 1 diabetes aged 27-61 years (age 45±9 years, 53% female, duration of diabetes 23±8 years, HbA(1c) 7.5±0.9%, IFCC=58 mmol/mol). Multiple linear regression models were fit to examine the association between glucose infusion rate and fasting lipid levels with adjustment for possible confounders. RESULTS: Lower glucose infusion rate was significantly associated with lower levels of HDL cholesterol in youths with Type 1 diabetes and with higher levels of triglycerides and higher triglyceride/HDL ratio in both youths and adults. The magnitude of the associations between glucose infusion rate and lipid levels translate into interquartile differences of 0.098 mmol/l for HDL cholesterol, 0.17 mmol/l for triglycerides and 1.06 for triglycerides/HDL in the adolescents and 0.20 mmol/l for triglycerides and 1.01 for triglycerides/HDL in the adults. The associations were attenuated and no longer statistically significant by adjustment for adiposity among adults, while adjustment for HbA(1c) had a small effect in youths and adults. CONCLUSIONS: Lower insulin sensitivity is associated with a more atherogenic lipid profile in both youths and adults with Type 1 diabetes.

Association of exposure to diabetes in utero with adiposity and fat distribution in a multiethnic population of youth: the Exploring Perinatal Outcomes among Children (EPOCH) Study.

AIMS/HYPOTHESIS: To evaluate whether exposure to maternal gestational diabetes (GDM) is associated with adiposity and fat distribution in a multiethnic population of children. METHODS: Retrospective cohort study of 82 children exposed to maternal GDM and 379 unexposed youths 6-13 years of age with measured BMI, waist circumference, skinfold thickness, and visceral and subcutaneous abdominal fat. RESULTS: Exposure to maternal GDM was associated with higher BMI (p = 0.02), larger waist circumference (p = 0.004), more subcutaneous abdominal fat (p = 0.01) and increased subscapular to triceps skinfold thickness ratio (p = 0.01) in models adjusted for age, sex, race/ethnicity and Tanner stage. Adjustment for socioeconomic factors, birthweight and gestational age, maternal smoking during pregnancy and current diet and physical activity did not influence associations; however, adjustment for maternal pre-pregnancy BMI attenuated all associations. CONCLUSIONS/INTERPRETATION: Exposure to maternal GDM is associated with increased overall and abdominal adiposity, and a more central fat distribution pattern in 6- to 13-year-old youths from a multi-ethnic population, providing further support for the fetal overnutrition hypothesis.

Cardiovascular risk factors in children exposed to maternal diabetes in utero.

AIMS/HYPOTHESIS: Recent studies have provided evidence that intrauterine exposure to maternal diabetes has lifelong effects on adult offspring, including increased risks of obesity, type 2 diabetes and cardiovascular disease. The aim of this study was to assess the relationship between exposure to maternal diabetes in utero and cardiovascular risk factors in healthy children and to investigate whether these associations are independent of maternal prepregnancy BMI and offspring attained BMI. METHODS: Data were from a retrospective cohort of children aged 6-13 years born during 1994-2002. Multiple linear regression was used to examine the associations between exposure and cardiovascular risk factors with adjustment for demographic factors and pubertal stage and additionally for maternal prepregnancy BMI and offspring attained BMI. RESULTS: Ninety-nine offspring of diabetic pregnancies had significantly increased E-selectin, vascular adhesion molecule 1 (VCAM1), leptin, waist circumference, BMI and systolic blood pressure and decreased adiponectin levels compared with 422 offspring of non-diabetic pregnancies after adjustment for age, sex and race/ethnicity (p < 0.05 for each risk factor). Additional adjustment for maternal prepregnancy BMI substantially attenuated group differences in the risk factors except for E-selectin, VCAM1 and waist circumference, which remained significantly higher in exposed children. CONCLUSIONS/INTERPRETATION: Compared with unexposed children, healthy offspring exposed to maternal diabetes in utero have a worse cardiovascular risk profile. In particular, offspring have substantially increased levels of circulating cellular adhesion molecules, which are biomarkers of adverse endothelium perturbation and may be related to the earliest preclinical stages of atherosclerosis and diabetes.

Conversion to dementia from mild cognitive disorder: the Cache County Study.

OBJECTIVE: To examine 3-year rates of conversion to dementia, and risk factors for such conversion, in a population-based sample with diverse types of cognitive impairment. METHODS: All elderly (aged 65 or older) residents of Cache County, UT, were invited to undergo two waves of dementia screening and assessment. Three-year follow-up data were available for 120 participants who had some form of mild cognitive impairment at baseline. Of these, 51 had been classified at baseline with prodromal Alzheimer disease (proAD), and 69 with other cognitive syndromes (CS). RESULTS: Three-year rates of conversion to dementia were 46% among those with cognitive impairment at baseline. By comparison, 3.3% without impairment converted to dementia in the interval. Among converters, AD was the most common type of dementia. In individuals with at least one APOE epsilon4 allele, those with proAD or CS exhibited a 22- to 25-fold higher risk of dementia than cognitively unimpaired individuals (vs 5- to 10-fold higher risk in those without epsilon4). CONCLUSIONS: Individuals with all types of mild cognitive impairment have an elevated risk of dementia over 3 years, more so in those with an APOE epsilon4 allele. These results suggest value in dementia surveillance for broad groups of cognitively impaired individuals beyond any specific category, and utility of APOE genotyping as a prognostic method.

Comparison of a picture-sort food-frequency questionnaire with 24-hour dietary recalls in an elderly Utah population.

OBJECTIVE: To evaluate the 137-item Utah Picture-sort Food-frequency Questionnaire (FFQ) in the measurement of usual dietary intake in older adults. DESIGN: The picture-sort FFQ was administered at baseline and again one year later. Three seasonal 24-hour dietary recall interviews were collected during the year between the two FFQs. Mean nutrient intakes were compared between methods and between administrations of the FFQ. SETTING: The FFQ interviews were administered in respondents' homes or care-centres. The 24-hour diet recalls were conducted by telephone interview on random days of the week. SUBJECTS: Two-hundred-and-eight men and women aged 55-84 years were recruited by random sample of controls from a case-control study of nutrition and bone health in Utah. RESULTS: After adjustment for total energy intake, median Spearman rank correlation coefficients between the two picture-sort FFQs were 0.69 for men aged < or = 69 years, 0.66 for men aged > 69 years; and 0.68 for women aged < or = 69 years, 0.67 for women aged > 69 years. Median correlation coefficients between methods were 0.50 for men < or = 69 years old, 0.52 for men > 69 years old; 0.55 for women < or = 69 years old, 0.46 for women > 69 years old. CONCLUSIONS: We report intake correlations between methods and administrations comparable to those reported in the literature for traditional paper-and-pencil FFQs and one other picture-sort method of FFQ. This dietary assessment method may improve ease and accuracy of response in this and other populations with low literacy levels, poor memory skill, impaired hearing, or poor vision.