The purpose of this study was to test the hypothesis that weight loss results in a reduction in intramuscular lipid (IMCL) content that is concomitant with enhanced insulin action. Muscle biopsies were obtained from morbidly obese individuals [body mass index (BMI) 52.2 Ϯ 2.5 kg/m 2 ; n ϭ 6] before and after gastric bypass surgery, an intervention that improves insulin action. With intervention, there was a 47% reduction (P Ͻ 0.01) in BMI and a 93% decrease in homeostasis model assessment, or HOMA (7.0 Ϯ 1.9 vs. 0.5 Ϯ 0.1). Histochemically determined IMCL content decreased (P Ͻ 0.05) by ϳ30%. In relation to fiber type, IMCL was significantly higher in type I vs. type II fibers. In both fiber types, there were reductions in IMCL and trends for muscle atrophy. Despite these two negating factors, the IMCL-to-fiber area ratio still decreased by ϳ44% with weight loss. In conclusion, despite differing initial levels and possible atrophy, weight loss appears to decrease IMCL deposition to a similar relative extent in type I and II muscle fibers. This reduction in intramuscular triglyceride may contribute to enhanced insulin action seen with weight loss. insulin resistance; obesity; skeletal muscle; triglyceride RECENT EVIDENCE INDICATES that the accumulation of triglyceride within skeletal muscle is related to insulin resistance. In humans, a negative association between whole-body insulin action and intramuscular lipid (IMCL) content has been observed (5,7,11,17,23,25,31,33). An elevated IMCL deposition has also been reported in obese individuals (6,7,18), obese individuals with type 2 diabetes (6), and the insulin resistantrelatives of type 2 diabetics (11,24). It is hypothesized that intermediates derived from IMCL sources such as triglyceride, i.e., long-chain acyl-CoAs and/or ceramide, directly induce insulin resistance by impeding insulin signal transduction (30). This type of mechanism would explain the negative relationship between IMCL accumulation and insulin action.Although an elevated IMCL content has been documented in a variety of insulin-resistant populations, information on the ability to reduce IMCL and concomitantly enhance insulin action with intervention, such as weight loss, is sparse and controversial. Either a reduction (6, 7) or no change (7, 19) in muscle triglyceride deposition with weight loss has been reported. However, in some of these studies, insulin action was either not measured (6) or did not improve (7, 19), making it difficult to elucidate the interaction between IMCL and insulin action. The purpose of the present study was to test the hypothesis that weight loss results in a reduction in IMCL content that is concomitant with enhanced insulin action. This was accomplished by examining IMCL deposition before and after a weight loss intervention (gastric bypass surgery) known to normalize insulin action in insulin-resistant, morbidly obese individuals (26).Although IMCL content is related to insulin action, a measurement of overall muscle triglyceride content may not be indicative of w...

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This paper discusses the flight test results of a real-time Digital Elevation Model (DEM) integrity monitor for Civil Aviation applications. Providing pilots with Synthetic Vision (SV) displays containing terrain information has the potential to improve flight safety by improving situational awareness and thereby reducing the likelihood of Controlled Flight Into Terrain (CFIT). Utilization of DEMs, such as the digital terrain elevation data (DTED), requires a DEM integrity check and timely integrity alerts to the pilots when used for flight-critical terrain-displays, otherwise the DEM may provide hazardous misleading terrain information. The discussed integrity monitor checks the consistency between a terrain elevation profile synthesized from sensor information, and the profile given in the DEM. The synthesized profile is derived from DGPS and radar altimeter measurements. DEMs of various spatial resolutions are used to illustrate the dependency of the integrity monitor's performance on the DEMs spatial resolution. The paper will give a description of proposed integrity algorithms, the flight test setup, and the results of a flight test performed at the Ohio University airport and in the vicinity of Asheville, NC.

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