Near-IR and IR imaging in lipid metabolism and obesity.

Approximately one-third of Americans are classified as obese. There has long been an interest in drug therapies for obesity. Interest in obesity research and in drug interventions in obesity has greatly increased since the discovery of a protein named leptin, one of apparently many competing biological signals in energy metabolism. The complexity of the obesity problem demands new non-invasive and non-destructive methods for monitoring lipid metabolism and energy expenditure to study the competing biological signals and their effects. A new computer algorithm for spectrometric imaging of living subjects is used to remove artifacts arising from subject motion from spectra and images. The algorithm is sufficiently simple to be implemented easily in hardware for real-time video processing. Because the algorithm can be applied to images, thermogenesis and lipid metabolism in interscapular adipose tissue can be observed directly in unrestrained and unanesthetized subjects using an InSb focal plane array video camera. The accuracy and precision of temperature and spectral measurements are established using laboratory references and prototype drugs in test subjects.