Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Respiratory system mechanics were evaluated in a 22-year-old asymptomatic man with absence of the left hemidiaphragm. We described changes in esophageal pressure (Pes), gastric pressure (Pga), chest wall configuration, and mediastinal motion during tidal breathing, breaths to total lung capacity (TLC), and Mueller maneuvers in the upright and supine position. We predicted that contraction of the single hemidiaphragm would drive the abdominal contents caudal on the side with the intact hemidiaphragm and displace the abdominal contents cephalad on the other side. This would drive the mediastinum toward the side with the intact diaphragm, thereby reducing its effectiveness in expanding the lung on that side. When upright, this effect would be minimized to the extent that the rib cage muscles lower pleural pressure in the thorax without the diaphragm. We found that (vital capacity) VC and TLC were greater upright than supine and that Pga deflections were almost as strongly negative as Pes deflections during upright quiet breathing and breaths to TLC. Thus the rib cage muscles enhanced the inspiratory action of the right hemidiaphragm in the upright position. In the supine position, Pes became negative without change of Pga during breaths to TLC and quiet inspirations. Here, contraction of the hemidiaphragm was the dominant mechanism generating the inspiratory pressure. During maximal Mueller efforts, the mediastinum shifted toward the side with the intact diaphragm in both positions and the maximum inspiratory pressures were low. These pressures were likely to have been limited by both the finite impedance to rotation of the thoracoabdominal contents or mediastinum and a mechanical disadvantage of the remaining hemidiaphragm. We conclude that the effectiveness of the single hemidiaphragm as an inspiratory pump requires passive impedance of the abdominal viscera and mediastinum and is enhanced in the upright position by the action of the rib cage muscles.
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PMID:Absence of a hemidiaphragm: mechanical implications. 206 24

In the present study, we assessed the occurrence of respiratory muscle rest during long lasting INPV runs using a pneumowrap ventilator at different pressure levels. We measured two indices of diaphragmatic activity: transdiaphragmatic pressure and the electrical activity of the diaphragm. Five healthy volunteers and six COPD patients were studied during spontaneous breathing and during 30-minute runs of INPV at a pressure of -2, -15 and -30 cmH2O. Ventilation, rib cage and abdomen motion were measured by inductive plethysmography; Pdi was obtained as the difference between gastric and esophageal pressures; Edi was recorded with surface electrodes. About 10 minutes of INPV (adaptation phase) were needed to obtain stable values in all the variables recorded. Ventilation increased in both groups up to threefold by increasing the negative pressure applied, this being due to changes in tidal volume. Changes in Pga swings mainly accounted for the reduction in Pdi that became negative during the run at -30 cmH2O. In both groups, Edi, after adaptation, showed no change during INPV at -2 cmH2O but a progressive reduction from control, during INPV at -15 and -30 cmH2O. We conclude that INPV by a pneumowrap ventilator can induce partial respiratory muscle rest in normal subjects and COPD patients.
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PMID:Diaphragmatic rest during negative pressure ventilation by pneumowrap. Assessment in normal and COPD patients. 211 51

To study respiratory muscle interaction in patients with occlusive apnea, diaphragmatic electromyogram (EMGdi) and gastric, pleural, and transdiaphragmatic pressures (Pga, Ppl, and Pdi, respectively) were studied in seven patients during non-rapid-eye-movement (NREM) sleep. Diaphragmatic force output, as assessed by Pdi, followed the periodic changes in EMGdi but during the occlusive phase the increase in Pdi was more than the increase in EMGdi. This increase in Pdi was essentially due to an increase in Ppl, since Pga and EMGdi had a linear relationship (r = 0.98, P less than 0.001) that did not change during the occlusive and ventilatory phases. Abdominal muscle recruitment evident in Pga and abdominal motion tracings during the occlusive phase when paradoxical rib cage motion was observed suggested that this increase in diaphragmatic efficiency was likely due to a change in diaphragmatic length-tension characteristics. These results demonstrate that, in patients with occlusive apneas, the diaphragm is the predominant respiratory muscle during NREM sleep and that its function is supported by abdominal muscle recruitment.
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PMID:Respiratory muscle interaction during NREM sleep in patients with occlusive apnea. 294 53

We continuously monitored esophageal (Pes) and gastric (Pga) pressures and used these measurements in a three-component model to estimate instantaneous diaphragmatic (DIA), inspiratory accessory muscle (IAM), and postexpiratory recoil (PER) pressures at various times during inspiration. We validated our model both by volume-pressure relationships of the respiratory system (Vrc-Pga and Vab-Pga, where Vrc and Vab are the rib cage and abdominal volumes, respectively) as well as electromyography of the respiratory muscles. Measurements were carried out at rest and during graded treadmill exercise in 11 subjects with chronic obstructive pulmonary disease (COPDs) and 8 age-matched normal subjects (AMNs). AMNs were 59 +/- 2 (SE) yr and had a forced expiratory volume at 1 s (FEV1.0) of 3.6 +/- 0.2 liters; COPDs were 66 +/- 2 yr and had a FEV1.0 of 1.0 +/- 0.1 liters. We noted the following. At rest, both AMNs and COPDs exhibited an increasing DIA pressure (PDIA) across inspiratory time (TI) at rest. As expired minute ventilation increased with exercise intensity, AMNs continued to maintain this PDIA ramp across inspiration; in contrast, COPDs exhibited higher values of PDIA during the first half of TI than during the second half. At all intensities of exercise, COPDs exhibited higher IAM and PER pressures than the AMNs.
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PMID:Inspiratory pressure generation: comparison of subjects with COPD and age-matched normals. 317 Apr 35

To test the hypothesis that during unsupported arm exercise (UAE) some of the inspiratory muscles of the rib cage partake in upper torso and arm positioning and thereby decrease their contribution to ventilation, we studied 11 subjects to measure pleural (Ppl) and gastric (Pga) pressures, heart rate, respiratory frequency, O2 uptake (VO2), and tidal volume (VT) during symptom-limited UAE. We used leg ergometry (LE) as a reference. Exercise duration was shorter for UAE vs. LE (207 +/- 67 vs. 514 +/- 224 s, P less than 0.05) even though the end-exercise VO2 was lower for UAE (9.3 +/- 1.1 vs. 30.8 +/- 3.2 ml.kg-1.min-1, P less than 0.05). Eight subjects had positive Ppl-Pga slopes and less negative end-inspiratory Ppl during UAE vs. LE (-11.8 +/- 6 vs. -19 +/- 7 cmH2O, P less than 0.05). This was not due to the lower VT's achieved during UAE, since at a similar VT, UAE resulted in a rightward and downward displacement of the Ppl-Pga slopes. Three of the subjects had irregular breathing rhythm and negative Ppl-Pga slopes as early as 1 min after initiation of UAE. They had shorter UAE duration and more dyspnea than the eight with positive Ppl-Pga slopes. In most subjects UAE decreases the ventilatory contribution of some of the inspiratory muscles of the rib cage as they have to partake in nonventilatory functions. This results in a shift of the dynamic work to the diaphragm and abdominal muscles of exhalation. In a few subjects UAE results in an irregular breathing pattern and very short exercise tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ventilatory muscle recruitment during unsupported arm exercise in normal subjects. 339 94

We investigated the respiratory muscle contribution to inspiratory load compensation by measuring diaphragmatic and intercostal electromyograms (EMGdi and EMGic), transdiaphragmatic pressure (Pdi), and thoracoabdominal motion during CO2 rebreathing with and without 15 cmH2O X l-1 X s inspiratory flow resistance (IRL) in normal sitting volunteers. During IRL compared with control, Pdi measured during airflow and during airway occlusion increased for a given change in CO2 partial pressure and EMGdi, and there was a greater decrease in abdominal (AB) end expiratory anteroposterior dimensions with increased expiratory gastric pressure (Pga), this leading to an inspiratory decline in Pga with outward AB movement, indicating a passive component to the descent of the abdomen-diaphragm. The response of EMGic to IRL was similar to that of EMGdi, though rib cage (RC)-Pga plots did infer intercostal muscle contribution. We conclude that during CO2 rebreathing with IRL there is improved diaphragmatic neuromuscular coupling, the prolongation of inspiration promoting a force-velocity advantage, and increased AB action serving to optimize diaphragm length and configuration, as well as to provide its own passive inspiratory action. Intercostal action provides increased assistance also. Therefore, compensation for inspiratory resistive loads results from the combined and integrated effort of all respiratory muscle groups.
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PMID:Respiratory muscle function during CO2 rebreathing with inspiratory flow-resistive loading. 621 76

The pressure swings under the costal (Pcos) and crural diaphragms (Pcru) and between the intestinal loops (Pint) were compared with the swings in gastric pressure (Pga) in 13 supine anesthetized dogs. Pcos, Pcru, and Pint were measured with air-filled latex balloons in eight dogs and saline-filled catheters in five. Pga was measured with an air-filled balloon in all dogs. During quiet breathing differences were often present, the directions of which were variable from animal to animal. During mechanical ventilation, all pressures increased, but both Pcos and Pcru increased more than Pga, whereas only a small change was observed in Pint. During bilateral stimulation of the costal diaphragm, Pcos invariably increased more than Pga and Pint, whereas almost no change was observed in Pcru. During bilateral stimulation of the crural diaphragm, Pcru invariably increased more than Pga, Pint, and Pcos. During abdominal muscle stimulation as during external abdominal compression, Pint always increased more than Pcos and Pcru. During lower rib cage compression, Pga, Pcos, and Pcru increased more than Pint. During sternocleidomastoid stimulation, all pressure swings were negative, but the change in Pint was always smaller than in Pcos, Pcru, or Pga. Inhomogeneities observed with balloons and saline-filled catheters were similar. After the abdomen was filled with 2 liters of saline all pressure swings became much more homogeneous.
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PMID:Regional differences in abdominal pressure swings in dogs. 651 43

In 10 anesthetized adult rabbits, we studied the effect of spontaneous breathing and positive pressure ventilation on pleural pressure on the costal lung surface (Ppl) and in the zone of apposition of the rib cage to the diaphragm (Papp). Ppl and Papp were measured by rib capsules installed in the 5th or 6th rib and 11th or 12th rib, respectively. Esophageal (Pes) and gastric (Pga) pressures were measured with air-filled balloons. At end expiration (functional residual capacity), Ppl was subatmospheric (-2.5 +/- 1.4 cm H2O), decreased during spontaneous inspiration, and was in phase with Pes. In contrast, Papp was above atmospheric pressure (2.1 +/- 1.8 cm H2O), increased during inspiration, and was in phase with Pga. Papp lagged Ppl by 180 degrees during spontaneous inspiration but was in phase with Ppl during mechanical ventilation. Changes in Ppl (delta Ppl) during inspiration were greater in magnitude than either delta Papp or delta Pga. Changes in transdiaphragmatic pressure in the zone of apposition (delta Pga-delta Papp) were near zero (-0.4 +/- 0.3 cm H2O), much smaller in magnitude than those (delta Pga-delta Ppl) associated with the lung (3.0 +/- 1.5 cm H2O). These results are consistent with the concept that during breathing, abdominal pressure is transmitted to the zone of apposition of the rib cage to the abdomen. During spontaneous breathing at rest, the pleural space in the zone of apposition is mechanically independent of the pleural space associated with the lung.
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PMID:Pleural pressure measured in the zone of apposition of diaphragm to rib cage in rabbits. 829 29

The relationship between gastroesophageal reflux (GER) and asthma remains controversial. Asthma symptoms worsen with GER, but are not consistently related to changes in lung function. The purpose of this study was to determine whether acid perfusion (AP) of the esophagus alters ventilation and causes respiratory symptoms. Nonasthmatic patients with normal lung function and esophageal disease (16 females and nine males, FEV1 %predicted = 99+/-9.6), underwent a Bernstein test after motility testing. Airflow, rib cage (Vrc), and abdominal (Vab) tidal volumes, esophageal (Pes) and gastric (Pga) pressure, and surface (Es) and esophageal (Edi) diaphragm electromyographic (EMG) signals were measured. Throat, swallowing, chest, and stomach discomfort and respiratory sensation were estimated with the Borg scale. Minute ventilation (VE) increased during AP and declined during recovery with saline perfusion of the esophagus (7.1+/-1.5 to 8.5+/-2.4 to 7.3+/-2.1 L/min; n = 25; p = 0.0002). Respiratory rate (RR) went from 13.6+/-2.6 to 15.8+/-3.4 to 15.3+/-3.1 breaths/min (n = 25; p = 0.0002) during AP. VE was greater in the Bernstein-positive patients during AP. Tidal volume (VT), Vrc, Vab, Pes, Pga, Es, and Edi did not change during AP. Chest discomfort (D) correlated with ventilation (VE = 0.7 + 0.8 D; r = 0.67; p < 0.001) and respiratory effort sensation (B) (B = 0.2 + 0.4 VE; r = 0.70; p < 0.001) during AP. AP did not inhibit diaphragm activity. Increased VE may explain the paradox of GER worsening respiratory symptoms without changing lung function.
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PMID:The effects of acid perfusion of the esophagus on ventilation and respiratory sensation. 956 19

Inspiratory muscle fatigue can probably determine hypercapnic respiratory failure. Diaphragm fatigue is detected by electrical phrenic stimulation (ELS), but there is no simple tool to assess rib cage muscle (RCM) fatigue. Cervical magnetic stimulation (CMS) costimulates the phrenic nerves and RCM. We reasoned that changes in transdiaphragmatic pressure twitch (Pdi,tw) with CMS and ELS should be different after selective diaphragm vs. RCM fatigue. Five volunteers performed inspiratory resistive tasks while voluntarily uncoupling diaphragm and RCM. Baseline Pdi,twELS and Pdi,twCMS were 28.57 +/- 1.68 and 32.83 +/- 2.92 cmH2O. After selective diaphragm loading, Pdi,twELS and Pdi,twCMS were reduced by 39 and 26%, with comparable decreases in gastric pressure twitch (Pga,tw). Esophageal pressure twitch (Pes,tw) was better preserved with CMS. Therefore Pes,tw/Pga,tw was lower with ELS than CMS (-1.24 +/- 0.16 vs. -1.73 +/- 0.11, P = 0.05). After selective RCM loading, there was no diaphragm fatigue, but Pes,twCMS was significantly reduced (-30%). These findings support the role of rib cage stiffening by CMS-related RCM contraction in the ELS-CMS differences and suggest that CMS can be used to assess RCM fatigue.
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PMID:Cervical magnetic stimulation as a method to discriminate between diaphragm and rib cage muscle fatigue. 957 19


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