.. sleep. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 44ftik 931-938, 1978. -Ten patients with daytime somnolence and obesity were found to have periodic airway occlusion (AO) during nocturnal sleep. The cyclical ventilatory pattern consisted of a series of regular inspiratory efforts against an occluded airway (occlusive phase) alternating with a period of regular breathing (ventilatory phase). Significant periods of central respiratory apnea were observed only in one case. The effects of pharyngeal intubation and pharyngeal pressure recordings showed that the locus of airway closure lay in the oropharynx. The genioglossal electromyogram (EMG) consistently revealed periodicity: low level activity at the onset of occlusion and prominent discharge at the instant of pharyngeal opening. In one case, this activity was closely related to pharyngeal patency, whereas in other cases there was considerable overlap between EMG values recorded during occluded and ventilatory phases. In these cases, the relationship of genioglossal discharge to pharyngeal pressure correlated with the presence or absence of pharyngeal occlusion. We speculate that genioglossal force act,s to open the oropharynx and that negative pharyngeal pressure promotes pharyngeal closure. The results are consistent with the idea that, once the pharvnx has collapsed, relative recruitment of genioglossal and inspiratory muscle act.ivity is such that the latter influence outstrips the former, so that pharyngeal transmural pressure increases more than genioglossal force. Pharyngeal opening occurs coincident with arousal and preferential activation of the genioglossus muscle of the tongue.

Pathogenesis of upper airway occlusion during sleep

Sleep-induced apnea and disordered breathing refers to intermittent, cyclical cessations or reductions of airflow, with or without obstructions of the upper airway (OSA). In the presence of an anat...

Pathophysiology of Sleep Apnea

Obstructive sleep apnea in infants and children.

Mismatches between neurotransmitter and receptor localizations in brain: observations and implications.

Recent studies consistently support a hypoxia response in the adipose tissue in obese animals. The observations have led to the formation of an exciting concept, adipose tissue hypoxia (ATH), in the understanding of major disorders associated with obesity. ATH may provide cellular mechanisms for chronic inflammation, macrophage infiltration, adiponectin reduction, leptin elevation, adipocyte death, endoplasmic reticulum stress and mitochondrial dysfunction in white adipose tissue in obesity. The concept suggests that inhibition of adipogenesis and triglyceride synthesis by hypoxia may be a new mechanism for elevated free fatty acids in the circulation in obesity. ATH may represent a unified cellular mechanism for a variety of metabolic disorders and insulin resistance in patients with metabolic syndrome. It suggests a new mechanism of pathogenesis of insulin resistance and inflammation in obstructive sleep apnea. In addition, it may help us to understand the beneficial effects of caloric restriction, physical exercise and angiotensin II inhibitors in the improvement of insulin sensitivity. In this review article, literatures are reviewed to summarize the evidence and possible cellular mechanisms of ATH. The directions and road blocks in the future studies are analyzed.

B Duron

Papers

Polygraphic study of the episodic diurnal and nocturnal (hypnic and respiratory) manifestations of the Pickwick syndrome.

Mechanism of the respiratory pauses accompanying slumber in the Pickwickian syndrome.

Comparative polygraphic study of the 24 hour cycle in Pickwickians, the obese and narcoleptics.

Spirographic and EMG analysis of respiration during sleep monitored by EEG in normal man.