Measurement of fat fraction in the human thymus by localized NMR and three-point Dixon MRI techniques.

Purpose: To develop a protocol to non-invasively measure and map fat fraction, fat/(fat+water), as a function of age in the adult thymus for future studies monitoring the effects of interventions aimed at promoting thymic rejuvenation and preservation of immunity in older adults.

Materials And Methods: Three-dimensional spoiled gradient echo 3T MRI with 3-point Dixon fat-water separation was performed at full inspiration for thymus conspicuity in 36 volunteers 19 to 56 years old. Reproducible breath-holding was facilitated by real-time pressure recording external to the console.

Selective contribution of regional adiposity, skeletal muscle, and adipokines to glucose disposal in older adults.

Objectives: To study the relationships between muscle mass, regional adiposity, and adipokines and glucose disposal in an older population.

Design: Cross-sectional analysis.

Setting: Community-dwelling volunteers from the Baltimore Longitudinal Study of Aging.

Contribution of central adiposity to left ventricular diastolic function (from the Baltimore Longitudinal Study of Aging).

We examined the relations of central adiposity with left ventricular (LV) diastolic dysfunction in men and women who participated in the Baltimore Longitudinal Study of Aging, a prospective community-based study of older persons. The sample for this cross-sectional analysis included 399 women and 370 men. Central adiposity was estimated using the waist circumference (WC) and global adiposity using the body mass index (BMI).

Towards segmentation of the thymus in fat and water parametric MR images.

The thymus, an organ responsible for the development, selection, and maintenance of the peripheral T-cell population, is an important regulator of the immune system. Despite its physiological significance, it has received little attention in the medical image analysis literature. In practice, the anatomical location and variable shape of this gland pose challenges both in the image acquisition and analysis processes.

Cross-sectional evidence of a signaling pathway from bone homeostasis to glucose metabolism.

Context: Preclinical studies suggested the existence of a signaling pathway connecting bone and glucose metabolisms. Supposedly leptin modulates osteocalcin bioactivity, which in turn stimulates insulin and adiponectin secretion, and β-cell proliferation.

Objective: The objective of the investigation was to study the reciprocal relationships of adiponectin, leptin, osteocalcin, insulin resistance, and insulin secretion to verify whether such relationships are consistent with a signaling pathway connecting bone homeostasis and glucose metabolism.

Glucose and insulin measurements from the oral glucose tolerance test and relationship to muscle mass.

Background: Diabetes is associated with decreased muscle mass. The effect of higher levels of glucose and insulin on muscle mass has not been studied in individuals without diabetes. We sought to determine the relationship of insulin and glucose measurements from the oral glucose tolerance test (OGTT) with muscle mass in persons without diabetes.