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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In man, there is wide interindividual range in the tidal volume response to CO2. To determine which (rib cage or abdomen-diaphragm) compartment had a greater influence on this range, ventilatory response to CO2 was measured, using Read's method, in eight men and two women seated in a constant-pressure body plethysmograph. Rib cage and abdominal tidal volume was simultaneously measured using magnetometers. Correcting for body size, the tidal volume response of the abdominal compartment was similar in all subjects, whereas that of the rib cage was larger in subjects with high tidal volume response to CO2; a significant correlation was found (P less than 0.01). Rib cage volume displacement lagged behind abdominal in all subjects; phase lag was greatest in the subject with the lowest ventilatory response to CO2. These results suggest that, at high levels of ventilation, a larger volume displacement of the rib cage may reflect a more effective coupling of the diaphragm pressure generator to it or alternatively a reduction in its impedance relative to the abdominal compartment.
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PMID:Contribution of rib cage and abdomen-diaphragm to tidal volume during CO2 rebreathing. 15 12

A new method for perfusion of rat lungs in situ was developed for metabolic studies. The pulmonary circulation was cannulated without contacting the lungs, which remained in the thoracic cage. Perfusion was continued for up to 4 h with Krebs-Henseleit bicarbonate buffer, equilibrated with 95% O2- 5% CO2 and containing 4.5% bovine serum albumin, 5.6 mM glucose, and levels of amino acids normally found in rat plasma. At an arterial pressure of 20 cmH2O flow remained constant (10.9 ml/min.100 g body wt) and appeared evenly distributed among the lobes. Tidal volume was 1 ml/100 g body wt (72/min); positive end-expiratory pressure was 2 cmH2O. The preparation remained stable and metabolically active for 4 h, as evidenced by a minimal decline in dry-to-wet weight ratio, constant levels of ATP and glycogen, a high ratio of glucose uptake to lactate production, and a linear rate of incorporation of [14C]phenylalanine into protein. The lungs were unaffected when perfusate oxygen was reduced to a more physiological level (20% O2-75% N2-5% CO2). In the presence of 95% N2-5% CO2 dry-to-wet weight ratio, ATP, glycogen, and amino acid incorporation decreased, while lactate production doubled.
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PMID:In situ perfusion of rat lungs: stability and effects of oxygen tension. 46 88

The ventilatory response to CO2 was subdivided into that portion due to increasing rib cage expansion, and that due to increased diaphragmatic descent. Five children were studied, awake, and anesthetized with halothane, 0.8-0.9%. During anesthesia there was a 67+/-8% reduction (mean+/-SE) in the slope of the response of overall ventilation to an increase in CO2. This was primarily due to an 89+/-8% reduction in the recruitment of rib cage ventilation (P less than .001). There was no significant change in the slope of the diaphragmatic response (anesthetized value 19+/-21% less than control), although the response curve was shifted to the right so that a higher CO2 concentration was needed to stimulate a given level of diaphragmatic excursion. Additional measurements of the inspiratory intercostal electromyogram in three adult subjects documented a rapid, profound depression of intercostal activity with halothane anesthesia that was associated with a marked decrease in rib cage ventilation. The authors conclude that a major component of the ventilatory depression associated with halothane anesthesia results from the preferential suppression of intercostal muscle function with relative sparing of diaphragmatic activity.
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PMID:Contributions of changing rib cage--diaphragm interactions to the ventilatory depression of halothane anesthesia. 90 May 41

This report describes the design and construction of a metabolism cage that allows for separation of urine and feces and for trapping expired CO2. Such a cage could find use in pharmacokinetic studies of drug excretion rates where potential metabolism to CO2 should be considered. To demonstrate the separation qualities of this cage design, the radioactivity appearing in the urine, feces, and exhaust gases was determined daily for 14 days after the single oral administration of 26-[14C]cholesterol. Less than 1% of the administered radioactivity appeared in the urine, whereas 61% appeared in the feces and 19% in the expired CO2.
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PMID:Metabolism cage for carbon dioxide trapping studies. 92 94

The recordings from an earlier study regarding the respiratory depth and rate changes induced by exposure to 4% CO2 in air in 13 babies with PM age varying between 32 and 43 weeks were reexamined with regard to the pattern of thoracic abdominal breathing excursion in breathing immediately prior to the CO2 exposure and the type of response induced. The pattern was called "stable" when the thoracic breathing excursions were in phase and congruent with the abdominal ones. When the thoracic excursions in comparison with the abdominal excursions were totally inverted, or incongruous but in phase, or rapidly varying between those two, the pattern was called "unstable". "Unstable" pattern of the breathing prior to the CO2 exposures was followed in an incidence of 60% by the type of response to CO2 which is characterized by a prompt rate increase (the "Type B" response) and only in 16% by the type characterized by an increased breathing amplitude (the "Type A" response). When the excursion pattern of the breathing prior to the CO2 exposures was "stable" "Type A" responses were induced in 59% and "Type B" responses in only 14%. The excursion pattern present when a baby is exposed to 4% CO2 thus seems to affect the type of respiratory depth and rate changes achieved. With increasing postmenstrual age the excursion pattern of the spontaneous breathing is more often "stable" and respiratory depth and rate changes of the "Type B" induced by CO2 less common. The variabilities of the breathing seen preferably in the preterm baby regarding regularity, rate and tidal volumes (as they could be approximated by the registration methods used) were noted most when the excursion pattern was "unstable". The results can be hypothetically interpreted to indicate a dynamic interaction between the thoracic wall and pulmonary mechanoreceptor systems of respiratory regulation. The decreasing variability of the breathing seen with increasing maturation in the baby could be explained by an increasing maturation of the neuromuscular ability to provide stability to the rib cage which would act stabilizing on the pulmonary vagal afferent input to the respiratory center.
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PMID:Control of respiration in newborn babies. IV. Rib cage stability and respiratory regulation. 94 1

A glass metabolic cage was designed for studies involving newborn rats and small animals up to about 15 g. The metabolic chamber is a jacketed tube, open on both ends and closed with 0-ring clamps. Water is circulated around the cage to maintain a constant and physiologic chamber temperature. Information about the metabolic pathway of nutrients and drugs can thus be studied, and the effects of drugs on metabolism of substrates to CO2 can also be assessed in the newborn animal.
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PMID:Design of a metabolic cage for infant rats. 114 30

To clarify the effect of respiratory muscle fatigue on ventilatory response to carbon dioxide, we performed CO2 rebreathing study before and after diaphragmatic fatigue in nine healthy males. Diaphragmatic fatigue was induced by inspiratory resistor loading and confirmed by the increase in Tension Time Index and the decrease in Pdi max at FRC. The effects of diaphragmatic fatigue were as follows: 1) S and B value of VE-CO2 curve did not change. 2) P1-CO2 curve shifted to the left but the slope of the curve did not change. 3) delta Ppl response to CO2 decreased, but delta Pdi response to CO2 did not change. 4) The increase in respiratory accessory muscle EMG was more prominent, compared to diaphragmatic EMG. 5) Rib cage movement became more marked. In conclusion, diaphragmatic fatigue (with 60 percent decrease in Pdi max at FRC) does not affect on ventilatory response to carbon dioxide. To maintain the homeostasis of the chemical ventilatory feedback system, diaphragmatic dysfunction is compensated by the increased activity of respiratory accessory muscles with possible increase in neural drive.
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PMID:[Effect of diaphragmatic fatigue on ventilatory response to carbon dioxide]. 130 16

The feasibility of using bacteria-derived hyaluronate solution as a viscous aid for anterior chamber surgery was examined by studying the pharmacokinetic behavior and metabolic fate of 14C-labelled material, following administration to rats and rabbits. Intravenously-administered HA disappeared rapidly from the blood of rabbits and rats with a mean t1/2 of 5.3 and 3.7 min, respectively. The labelled material has concomittantly accumulated in the liver, where it was digested to oligomeric sugar subunits; these were further utilized metabolically either for energy generation or for incorporation into new high molecular weight species. Metabolic cage studies has indicated that most of the 14C-HA label administered intravenously to rats was excreted as CO2 via the respiration within 24h, while a smaller portion was excreted in the urine. The disposition of viscous 14C-HA administered into the anterior eye chamber of rabbits was slow and followed first-order kinetics with a t1/2 of 10.5h. No degradation occurred in the aqueous humour. Low blood levels of 14C-labeled material were found during 72h after intra-ocular administration. The results indicate that the absorption, distribution, metabolism and excretion of bacteria-derived HA is similar to those of the currently used ophthalmic surgery HA aids extracted from rooster combs.
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PMID:Absorption, distribution, metabolism, and excretion of bacteria-derived hyaluronic acid in rats and rabbits. 150 57

We studied the effects of elective hip surgery, performed under either spinal (SA, n = 10) or general anesthesia (GA, n = 10), on breathing pattern and gas exchange. Measurements were made with respiratory inductive plethysmograph and indirect calorimetry in two positions before and after surgery. The method of anesthesia had no effect on the severity of postoperative hypoxemia. Reduced arterial oxygenation (PaO2; P less than 0.001, SA from 12.5 +/- 2.37 kPa to 10.5 +/- 1.38 kPa, GA from 12.5 +/- 2.95 kPa to 10.5 +/- 1.75 kPa) despite increased alveolar ventilation (P less than 0.01; from 2.30 +/- 0.37 l/min to 2.39 +/- 0.43 l/min in SA, 2.27 +/- 0.56 l/min to 2.57 +/- 0.35 l/min in GA) and reduced arterial carbon dioxide partial pressure (PaCO2; SA from 5.20 +/- 0.22 kPa to 4.95 +/- 0.33 kPa, P less than 0.01, GA from 5.07 +/- 0.36 kPa to 4.72 +/- 0.41 kPa, P less than 0.05) indicated maldistribution of ventilation and perfusion. Changes in breathing pattern and gas exchange and differences between the groups were minimal. Minute ventilation, tidal volume and mean inspiratory flow remained unchanged in both groups. The contribution of rib cage to tidal volume increased postoperatively in the supine position (P less than 0.001; SA from 32.6% +/- 10.3 to 46.3% +/- 7.5, GA from 36.5 +/- 16.4 to 48.5% +/- 15.4). CO2 production, oxygen consumption and energy expenditure remained unchanged. The postoperative changes in breathing pattern are related to the operation, not to the type of anesthesia and do not explain the alterations in gas exchange.
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PMID:Does the anesthetic method influence the postoperative breathing pattern and gas exchange in hip surgery? A comparison between general and spinal anesthesia. 153 71

The aim of our study was to examine the effect of posture on inspiratory muscle activity response to hypercapnia. Recent research has revealed that in normal subjects the activation of the rib cage muscles and of the diaphragm is actually greater in the upright than in the supine position during resting tidal breathing. In this study we examined whether the upright position necessarily entails a greater activation of the inspiratory muscles also under conditions of ventilatory stress. For this purpose we compared the responses to CO2-rebreathing in the supine and sitting positions in five volunteers, by simultaneously recording the electromyogram of the diaphragm (EMGdi) and the intercostal muscles (EMGint). The electromyogram was recorded by means of surface electrodes to measure the EMG amplitude. While the slopes of ventilatory (VE) response to increasing arterial CO2 tension (PaCO2) were similar in the two positions, both the EMGdi-VE and EMGint-VE relationship showed steeper slopes in the supine than in the sitting position. In each CO2 run the increases in EMGdi were linearly related to those in EMGint. This relationship was not affected by the body position. These results suggested that, in spite of similar ventilatory responses to CO2-rebreathing in the lying and sitting positions, the supine position, in humans, required a higher activation of the inspiratory muscles.
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PMID:Effect of posture on inspiratory muscle electromyogram response to hypercapnia. 156 72


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