Louis M, Punjabi NM. Effects of acute intermittent hypoxia on glucose metabolism in awake healthy volunteers. J Appl Physiol 106: 1538 -1544, 2009. First published March 5, 2009 doi:10.1152/japplphysiol.91523.2008.-Accumulating evidence suggests that obstructive sleep apnea is associated with alterations in glucose metabolism. Although the pathophysiology of metabolic dysfunction in obstructive sleep apnea is not well understood, studies of murine models indicate that intermittent hypoxemia has an important contribution. However, corroborating data on the metabolic effects of intermittent hypoxia on glucose metabolism in humans are not available. Thus the primary aim of this study was to characterize the acute effects of intermittent hypoxia on glucose metabolism. Thirteen healthy volunteers were subjected to 5 h of intermittent hypoxia or normoxia during wakefulness in a randomized order on two separate days. The intravenous glucose tolerance test (IVGTT) was used to assess insulin-dependent and insulin-independent measures of glucose disposal. The IVGTT data were analyzed using the minimal model to determine insulin sensitivity (SI) and glucose effectiveness (SG). Drops in oxyhemoglobin saturation were induced during wakefulness at an average rate of 24.3 events/h. Compared with the normoxia condition, intermittent hypoxia was associated with a decrease in SI [4.1 vs. 3.4 (mU/l) Ϫ1 ⅐ min Ϫ1 ; P ϭ 0.0179] and SG (1.9 vs. 1.3 min Ϫ1 ϫ10 Ϫ2 , P ϭ 0.0065). Despite worsening insulin sensitivity with intermittent hypoxia, pancreatic insulin secretion was comparable between the two conditions. Heart rate variability analysis showed the intermittent hypoxia was associated with a shift in sympathovagal balance toward an increase in sympathetic nervous system activity. The average R-R interval on the electrocardiogram was 919.0 ms during the normoxia condition and 874.4 ms during the intermittent hypoxia condition (P Ͻ 0.04). Serum cortisol levels after intermittent hypoxia and normoxia were similar. Hypoxic stress in obstructive sleep apnea may increase the predisposition for metabolic dysfunction by impairing insulin sensitivity, glucose effectiveness, and insulin secretion. sleep apnea; diabetes; insulin resistance; glucose intolerance THE GLOBAL PREVALENCE of Type 2 diabetes mellitus is increasing in epidemic proportions. It is estimated that Type 2 diabetes affects ϳ150 million people worldwide and that its prevalence is likely to almost double by the year 2025 (19). Over the last decade, considerable progress has been made in our understanding of the factors that increase the propensity for Type 2 diabetes. It is now abundantly clear that insulin resistance and pancreatic ␤-cell dysfunction are common by the time hyperglycemia develops (34). Risk factors for Type 2 diabetes include age, race, family history, obesity, and sedentary lifestyle (1). In recent years, there has been increasing recognition that obstructive sleep apnea may also be an independent risk factor for altered glucose metabolism. Indeed, a num...

First developed for coverage of burn wounds, Integra (Integra LifeSciences) is a synthetic acellular dermal regeneration template that provides a base for revascularization and neodermal formation. The use of Integra has slowly grown and has now become an important consideration along the reconstructive ladder. This article reviews the basic science of Integra and provides an overview of the many expanding applications based on anatomic location.

No abstract

Since the pioneering use of autologous rib cartilage for the reconstruction of microtia, there have been significant advances in surgical technique that have helped to ameliorate the psychological burden of microtia. To date, the use of rib cartilage for auricular reconstruction is one of the most enduring and ubiquitous techniques for microtia reconstruction as it provides excellent aesthetic results with lasting durability. In this review, the authors outline the most common methods of microtia reconstruction with a comparison of each technique and illustrative case examples.