What is Sustainability and How Do We Measure It?

What Does It Mean and How Do We Measure It?

T he paper by Bonow et al' in this issue of Circulation reports important empirical observations on measuring myocardial viability in humans with the potassium analogue thallium-201. After obtaining standard 20'1f exercise and redistribution images, a second dose of 201TI was injected and a third (reinjection) image was obtained beginning 10-15 minutes later. The reinjection images identified v...

Evolvability: What Is It and How Do We Get It?

Cytogenetic biodosimetry: what it is and how we do it.

Dicentric assay is the international gold standard for cytogenetic biodosimetry after radiation exposure, despite being very labour-intensive, time-consuming, and highly expertise-dependent. It involves the identification of centromeres and structure of solid-stained chromosomes and the enumeration of dicentric chromosomes in a large number of first-division metaphases of cultured T lymphocytes...

Examining the developing bone: What do we measure and how do we do it?

The clinical tools available to evaluate bone development in children are often ambiguous, and difficult to interpret. Unfortunately bone densitometry methods (i.e., dual energy X-ray absorptiometry, DXA) which have a relatively straightforward application in adult osteoporosis, are far more difficult to evaluate in the growing skeleton. Even with adequate "adjustment" for bone size or maturity...

Insulin Resistance – What Is It and How Do We Measure It?

Insulin resistance is defined as the diminished ability of cells to respond to the action of insulin in transporting glucose (sugar) from the bloodstream into muscle and other tissues. In humans, insulin resistance typically develops with obesity and heralds the onset of type 2 (non-insulin-dependent) diabetes (Shepherd and Kahn, 1999). In horses, insulin resistance is commonly associated with ...