Respiratory physiology & neurobiology
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Respir Physiol Neurobiol · Apr 2011
Cartography of human diaphragmatic innervation: preliminary data.
In humans, anatomy indicates that the phrenic nerve mainly arises from the C4 cervical root, with variable C3 and C5 contributions. How this translates into functional innervation is unknown. The diaphragm response to electrical stimulation of C3, C4 and C5 was described in three patients undergoing surgical laryngeal reinnervation with an upper phrenic root (surface chest electrodes at anterior, lateral and posterior sites; oesophageal and gastric pressures (Pes and Pga) to derive transdiaphragmatic pressure (Pdi)). ⋯ It produced Pdi values of 9, 11, and 14cmH(2)O in the three patients, respectively, vs. 9, 9, and 7cmH(2)O for C4. C3 stimulation produced modest Pdi responses, whereas C5 stimulation could produce Pdi responses close to those observed with C4 stimulation. These singular observations confirm the dominance of C4 in diaphragm innervation but suggest than C5 can be of importance.
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Respir Physiol Neurobiol · Mar 2011
Clinical TrialEffects of venous compression of the legs on overnight rostral fluid shift and obstructive sleep apnea.
The amount of fluid displaced overnight from the legs into the neck as a consequence of lying recumbent correlates with the number of apneas and hypopneas per hour of sleep (AHI). Sedentary living promotes dependent fluid accumulation in the legs that can be counteracted by venous compression of the legs (compression stockings). ⋯ The median AHI decreased from 30.9 (interquartile range 19.6-60.4) to 23.4 (12.9-31.8) (P=0.016) in association with a median 40% reduction in the change in leg fluid volume (P=0.016) and a median 42% reduction in the increase in neck circumference (P=0.016). These results provide proof-of-principle that overnight fluid displacement into the neck plays a causative role in OSA.
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Respir Physiol Neurobiol · Feb 2011
Analysis of the pharynx and the trachea by the acoustic reflection method in children: a pilot study.
The acoustic reflection method (ARM) is based on the analysis of the reflection of acoustic waves. The aim of the study was to determine the feasibility of the ARM in healthy children, and the anthropometric parameters that were correlated with the minimum cross-sectional area (MCAv) of the upper airways. ⋯ The MCAv values correlated significantly with height, age, and weight, but in a stepwise multiple regression analysis, only height remained correlated with the MCAv (r=0.59, p<0.0001). The analysis of the upper airways by the ARM is feasible in children after 2 years of age and the MCAv values increase with height in childhood.
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The generation of reactive oxygen species (ROS) plays a major role in endothelial signaling and function. Of the several potential sources of ROS in the vasculature, the endothelial NADPH oxidase (Nox) family of proteins, Nox1, Nox2, Nox4 and Nox5, are major contributors of ROS. Excess generation of ROS contributes to the development and progression of vascular disease. ⋯ Physiological concentrations of ROS function as signaling molecule in the endothelium; however, excess ROS production leads to pathological disorders like inflammation, atherosclerosis, and lung injury. Regulation of Nox proteins is unclear; however, antioxidants, MAP Kinases, STATs, and Nrf2 regulate Nox under normal physiological and pathological conditions. Studies related to redox regulation of Nox should provide a better understanding of ROS and its role in the pathophysiology of vascular diseases.
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Respir Physiol Neurobiol · Sep 2010
Degree of endothelium injury promotes fibroelastogenesis in experimental acute lung injury.
We tested the hypothesis that at the early phase of acute lung injury (ALI) the degree of endothelium injury may predict lung parenchyma remodelling. For this purpose, two models of extrapulmonary ALI induced by Escherichia coli lipopolysaccharide (ALI-LPS) or cecal ligation and puncture (ALI-CLP) were developed in mice. ⋯ Conversely, the number of lung apoptotic cells was similar in both groups. In conclusion, the intensity of fibroelastogenesis was affected by endothelium injury in addition to the maintenance of epithelial damage and intraperitoneal inflammation.