The diaphragm muscle of hyperkalemic periodic paralysis (HyperKPP) patients and of the M1592V HyperKPP mouse model rarely suffers from the myotonic and paralytic symptoms that occur in limb muscles. Enigmatically, HyperKPP diaphragm expresses the mutant NaV1.4 channel and, more importantly, has an abnormally high Na(+) influx similar to that in extensor digitorum longus (EDL) and soleus, two hi...

During physiological spontaneous breathing maneuvers, the diaphragm displaces volume while maintaining curvature. However, with maximal diaphragm activation, curvature decreases sharply. We tested the hypotheses that the relationship between diaphragm muscle shortening and volume displacement (VD) is nonlinear and that curvature is a determinant of such a relationship. Radiopaque markers were s...

the case is 43 years old woman referred to emergency department of our hospital with quadriplegia and severe respiratory insufficiency due to c5-c6 injury after falling. she discharged from icu after fixation of the lesion and successful weaning. we evaluated electrical activity of diaphragm signal (edi), respiratory drive (p100) during one month period. we detected increase in level of electri...

Recent studies proposed that mechanical inactivity of the human diaphragm during mechanical ventilation rapidly causes diaphragm atrophy and weakness. However, conclusive evidence for the notion that diaphragm weakness is a direct consequence of mechanical inactivity is lacking. To study the effect of hemidiaphragm paralysis on diaphragm muscle fiber function and structure in humans, biopsies w...

Patients with heart failure (HF) have diaphragm abnormalities that contribute to disease morbidity and mortality. Studies in animals suggest that reactive oxygen species (ROS) cause diaphragm abnormalities in HF. However, the effects of HF on ROS sources, antioxidant enzymes, and protein oxidation in the diaphragm of humans is unknown. NAD(P)H oxidase, especially the Nox2 isoform, is an importa...

[Purpose] This study investigated the effects of progressive load and fixed load high-intensity inspiratory muscle training on the asymmetry of diaphragm thickness in stroke patients. [Subjects] Twenty-one stroke patients were assigned to one of three groups: progressive load high-intensity inspiratory muscle training (n = 8), fixed load high-intensity inspiratory muscle training (n = 6), and c...

During isolated phrenic nerve stimulation, the muscles of the diaphragm shorten by 40-50% of their optimal length, and the force in the muscle and transdiaphragmatic pressure (Pdi) depend on the final muscle length. The muscle shortening depends on the load imposed on the diaphragm by pleural and abdominal pressures during a particular maneuver. The mechanics of the interaction between the diap...