Dual Photon Absorptiometry: Validation of Mineral and Fat Measurements

Heymsfield, Steven B.; Wang, Jack; Aulet, M.; Kehayias, Joseph J.; Lichtman, Steven W.; Kamen, Yakov; Dilmanian, F.A.; Lindsay, Robert; PiersonJr., Richard N.

doi:10.1007/978-1-4613-1473-8_45

Cited by 18 publications

(11 citation statements)

References 9 publications

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“…They were all healthy, nonsmokers, non-obese (body mass index ¼ 25^2 kg=m 2 ), with a normal physical examination, routine blood work and thyroid function tests, taking no medication, not depressed as assessed by the Beck questionnaire (14), with an oral glucose tolerance test within the normal range, and a stable body weight for at least 3 months prior to the study. Total body fat (mean 21^6%) was measured by DEXA scan (15). Their baseline glucose, insulin and leptin levels were respectively 5:1^0:4 mmol=l; 71^29 pmol=l and 5^4 ng=ml: The study protocols were approved by the Institutional Review Board of St Luke's/Roosevelt Hospital, and informed written consent was obtained prior to inclusion in the study.…”

Section: Subjectsmentioning

confidence: 99%

A pulse of insulin and dexamethasone stimulates serum leptin in fasting human subjects

Laferrère

Caixàs²,

Fried³

et al. 2002

European Journal of Endocrinology

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Objectives: We have previously shown that dexamethasone increases serum leptin in fed but not in fasted human subjects. We hypothesized that insulin and/or glucose mediated the effect of food intake. The primary aim of this study was to determine whether the administration of a pulse of insulin with dexamethasone was sufficient to increase serum leptin in vivo in fasted human subjects. Whether the presence of transient hyperglycemia and the dose of insulin were important was tested as a secondary aim. Methods: Twenty-nine normal subjects were studied. In experiment 1 (meal-like), a pulse of insulin (0.03 U/kg s.c.) and of dexamethasone (2 mg i.v.) was given, and the blood glucose transiently elevated to 50 mg/dl above baseline for the first 2 h. In experiments 2 and 3 (dose-response), the effect of two doses of insulin (0.03 U/kg in experiment 2 and 0.06 U/kg in experiment 3) was tested in combination with dexamethasone, this time without transient hyperglycemia. Nine subjects were studied under fasting conditions, with or without dexamethasone, as a control experiment. Results: A meal-like transient hyperinsulinemia and hyperglycemia, with a pulse of dexamethasone, increased serum leptin levels from baseline by 54^21% at 9 h ðP ¼ 0:038Þ: In the absence of transient hyperglycemia, leptin increased significantly after doses of both insulin and dexamethasone. The effect of insulin was dose-dependent, with a larger increment of serum leptin at 9 h after the highest dose of insulin ð75:2^15:7% vs 21:3^8:5%; P ¼ 0:013Þ. Fasting, with or without dexamethasone, resulted in a significant 20% decrease in leptin from morning basal levels. Conversely, the administration of a pulse of insulin and glucose, in the absence of dexamethasone, prevented the drop in serum leptin observed during fasting, regardless of the insulin dose or the serum glucose elevation. Conclusions: With the permissive effect of dexamethasone, a single pulse of insulin triggered a rise in serum leptin in humans, even in the absence of transient hyperglycemia. A single pulse of insulin with glucose can prevent the drop in serum leptin normally observed during fasting.

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Section: Subjectsmentioning

confidence: 99%

A pulse of insulin and dexamethasone stimulates serum leptin in fasting human subjects

Laferrère

Caixàs²,

Fried³

et al. 2002

European Journal of Endocrinology

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“…O interesse em definir a sarcopenia iniciou--se por uma analogia ao IMC para encontrar o índice relativo de massa esquelética 62,63 . Usando modelos alométricos baseados em correlações empíricas, Heymisfield et al 63 mostraram que a composição corporal avaliada pela inclusão do músculo esquelético dimensionava a altura com o poder igual ou superior a 2, para a maioria dos grupos, segundo sexo e raça, daí a razão da criação de uma altura ao quadrado variável ajustada 63 . Assim, a sarcopenia é avaliada pela relação entre o Músculo Esquelético Apendicular (MEA) dividido pela altura ao quadrado (MEA/m²), definindo o índice relativo de massa muscular.…”

Section: Análise Da Massa Muscular Em Obesosunclassified

Métodos de análise da composição corporal em adultos obesos

et al. 2014

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Os métodos de avaliação da composição corporal em obesos têm sido amplamente discutidos, uma vez que nesses indivíduos a avaliação é dificultada devido às limitações dos equipamentos e características dos métodos utilizados. Esta sessão temática tem o objetivo de esclarecer as características, vantagens e limitações dos métodos de avaliação da composição corporal em adultos obesos. A quantificação de gordura corporal e mas-sa livre de gordura, assim como a avaliação da perda de massa muscular e de massa óssea em obesos são temas de grande interesse científico, uma vez que são utilizados para diagnosticar a obesidade osteosarcopênica. A avaliação da composição corporal de obesos pelo modelo de múltiplos compartimentos é padrão-ouro na prática científica. Por outro lado, o método de absorciometria radiológica de feixe duplo é considerado o padrão de referência em pesquisas e na prática clínica. Estudos indicam que a ressonância magnética e a tomografia computadorizada, em alguns casos, são fortemente correlacionadas com a absorciometria radiológica de feixe duplo. Os demais métodos apresentam limitações em avaliar a composição corporal, bem como suas modificações durante a redução ponderal em indivíduos obesos.

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“…DPA operates by generating photons at two energy levels and then measuring the attenuation of photons as they pass through soft tissue and bone. These figures are then used to calculate body fat (for details see Heymsfield et al, 1990). UWW was chosen as the predictor (x) variable because it is generally accepted as a valid measure of fatness and for a long time was the standard in the field.…”

Section: Examplementioning

confidence: 99%

The analysis and identification of homologizer/moderator variables when the moderator is continuous: An illustration with anthropometric data

Allison

Heshka

Pierson

et al. 1992

American J Hum Biol

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Human biological data often contain homologizers, that is, variables which moderate the strength rather than the form of the relationship between two other variables. Current methods for the identification and analysis of continuous homologizer variables [Z] (variables which moderate the strength rather than the form of a relationship between other variables [X,Y]) recommend dividing the sample into subgroups on the basis of the homologizer variable (Z) and testing whether correlations (X,Y) are significantly different among subgroups. We propose an alternative strategy which avoids the use of subgroups and which offers greater power to detect homologizer effects. In addition, it allows the identification of homologizer effects in data sets where multiplicative as well as additive terms are included in the model. The proposed strategy is validated through Monte Carlo simulations and an example of its application to a set of anthropometric data is given. © 1992 Wiley-Liss, Inc.

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Dual Photon Absorptiometry: Validation of Mineral and Fat Measurements

Cited by 18 publications

References 9 publications

A pulse of insulin and dexamethasone stimulates serum leptin in fasting human subjects

A pulse of insulin and dexamethasone stimulates serum leptin in fasting human subjects

Métodos de análise da composição corporal em adultos obesos

The analysis and identification of homologizer/moderator variables when the moderator is continuous: An illustration with anthropometric data

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