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Irsigler G B - - 1980
The effect of induced metabolic acidosis (48 h of NH4Cl ingestion, BE - 10.6 +/- 1.1) and alkalosis (43 h of NaHCO3- ingestion BE 8.8 +/- 1.6) on arterial and lumber CSF pH, Pco2, and HCO3- and ventilatory responses to CO2 and to hypoxia was assessed in five healthy men. ...
Band D M - - 1980
We have monitored oscillations in arterial pH (of respiratory frequency) in normal man at rest and during exercise. The pH oscillations are known to reflect respiratory oscillations in arterial carbon dioxide tension generated at the lungs. We have found that the pH oscillations increase in their upslope and downslope during ...
Martin B J - - 1980
Morphine reduces ventilation (VE) in exercising man. The mechanism of this ventilatory depression remains unclear. Recent evidence suggests that morphine may reduce exercise VE by simultaneously reducing exercise metabolic rate. We measured exercise VE in six normal subjects after intravenous injection of either saline or 0.1 mg/kg morphine sulfate. During ...
Davis J A - - 1980
To characterize more precisely the relationship between ventilation (VE) and CO2 output (VCO2) during incremental exercise, 35 healthy males were studied at rest and during upright cycle ergometry, with the work rate incremented every 4 min up to each subject's anaerobic threshold (Oan). Twenty-one subjects had arterial blood sampled at ...
Ohkuwa T - - 1980
Ventilatory response lines to carbon dioxide at rest were determined by the rebreathing method in 10 untrained subjects, 17 sprint swimmers, and 11 long-distance swimmers. It was found that the mean slope of the ventilatory response line of the swimmer was lower than that of untrained group, and the mean ...
Lindahl J - - 1980
The endogenous production of 14CO during the first week after administration of 2-[14C]glycine, i.e. the early peak of 14CO derived mainly from erythropoietic and hepatic haem turnover, was measured in six normal subjects. Samples from the body CO store were collected by washout of CO with oxygen breathing, CO concentration ...
Onal E - - 1979
The effects of electrode position and gastric-balloon anchoring on esophageal diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in seven normal sitting humans using an esophageal catheter that consisted of four platinum wire coils enabling simultaneous recording of three EMGdi signals from three different sites in the esophagus. A ...
Killian K J - - 1979
The ability of normal subjects to detect the addition of external resistive loads was determined both at rest and when ventilation was increased to more than 30 L/min by CO2 administration or exercise. Tidal volume, flow, and mouth and transpulmonary pressures were recorded during resistive load discrimination using standard psychophysical ...
Jones N L - - 1979
The relation between end-tidal carbon dioxide tension (PETCO2) measured by infrared analysis and arterial carbon dioxide tension (PaCO2) during exercise was systematically examined in five healthy adults at two power outputs (25 and 50% VO2max) and at three frequencies of breathing (15, 30, and 45 breaths/min). PETCO2-PaCO2 varied between -2.5 ...
Kiley J P - - 1979
Adult White Pekin ducks were exercised for 20 min on a treadmill (3 degrees incline) at two speeds: 0.9 and 1.47 km/h. Each exercise period was followed by a 90-min rest. Heart rate and systolic and diastolic blood pressure increased significantly during each exercise period. During exercise, tidal volume decreased ...
Hildebrandt J R - - 1979
Cardiovascular and respiratory parameters were measured during and after release of pressure in thigh cuffs which occluded circulation to the legs of four human subjects exercising on a bicycle ergometer. The subjects exercised at 200 kg/min while thigh cuffs were inflated for 4 min and then released. Responses from 6 ...
Winn R - - 1979
Receptor sites for the ventilatory response to isoproterenol were investigated in anesthetized rabbits with bolus injections in the common carotid artery (ia) and in the vena cava (iv). The delay from injection to the increase in ventilation (TVE) was significantly shorter following ia (1.5 s) compared to iv injections (about ...
Levine S - - 1979
To assess the role of humoral mechanisms in eliciting the hyperpnea of muscular exercise, anesthetized dogs underwent complete spinal transection at the second lumbar level (L2). Muscular exercise of the denervated hindlimbs was then induced by electrical stimulation. Coincident with hindlimb muscle contraction, oxygen consumption (VO2) increased 173% and ventilation ...
Casaburi R - - 1979
Following exercise onset, CO2 output (VCO2) and O2 uptake (VO2) increase exponentially, but with appreciably different time constants. To determine the sensitivity of the time courses of these variables to altered ventilatory kinetics, rhythmic exercise was induced abruptly in anesthetized dogs by bilateral stimulation of the peripheral ends of the ...
Honda Y - - 1979
Exercise hyperpnea was compared in 5 asthmatics 25 yr after bilateral carotid body resection (BR), 4 others 19 yr after unilateral resection (UR), and 12 controls (C) matched for age and pulmonary flow limitation. In the BR group, ventilation rose less with exercise, mostly because BR experienced less tachypnea. End-tidal ...
Milsom W K - - 1979
Ventilatory responses of unanesthetized turtles to changes in the intrapulmonary CO2 content of a vascularly isolated and an intact lung were measured during spontaneous breathing. The hyperpnea associated with inhalation of CO2 by the vascularly isolated lung was 19% of that associated with inhalation of CO2 by the intact lung. ...
Weissman M L - - 1979
To investigate the importance of the major neural afferent component from the exercising extremities in exercise hyperpnea, rhythmic contraction of hindlimb muscles was produced in the dog, by electrically stimulating the peripheral cut ends of the sciatic and femoral nerves, bilaterally, for 4- to 5-min periods. VE, VCO2, and VO2 ...
Jones N L - - 1979
Body CO2 storage capacity was measured in nine subjects at two levels of exercise, approximating 30 and 60% VO2max, by measuring the excess CO2 output associated with hyperventilation at constant end-tidal PCO2, and the change in mixed venous PCO2 (PVCO2) measured by rebreathing. CO2 output was measured during 20-s periods ...
Jennings D B - - 1979
During acute hypercapnia (5% carbon dioxide) in resting conscious dogs, ventilation (Ve) attained a new level above control within 5 min, but rectal temperature decreased gradually to reach a steady state lower than control after 40-60 min. At 2 days of breathing 5% carbon dioxide, Ve remained elevated, as in ...
Schaeffer K E - - 1979
Physiological studies on hypercapnic effects carried out on 13 Polaris patrols are summarized. The average CO2 concentrations ranged from 0.7-1% CO2; CO2 was identified as the only environmental contaminant of the submarine atmosphere that has a direct effect on respiration in the concentration range found in the submarine atmosphere. A ...
Davies D M - - 1979
Studies in nuclear submariners show that calcium excretion falls rapidly to 50% of pre-patrol levels during long patrols and remains low for many weeks after return to fresh air. This has previously been attributed to a specific effect of continuous exposure to the inevitably raised ambient CO2 levels, but other ...
Sutton J R - - 1979
In reviewing the blood borne "mediators" to ventilation during exercise, our emphasis is on VCO2 and [H+]. We consider that exercise ventilation is more closely linked to VCO2 than to VO2. Lactic acid has a dual effect on ventilation, as it results in an increased CO2 output as well as ...
Whipp B J - - 1979
The carotid bodies appear to be the only peripheral chemoreceptors mediating ventilatory control during exercise in man. While little is known about the mechanism of stimulation, much is known about the effects of carotid body stimulation upon pulmonary ventilation (VE). These effects have been produced by hypercapnia, hypoxia, metabolic acidosis, ...
Mahler M - - 1979
This review analyzes attempts to isolate and quantify the neurally and humorally mediated portions of the ventilatory response to moderate exercise. 1. Dejours' "neuro-humoral theory" postulates that, following a change from rest to moderate, constant-load exercise in man, the abrupt initial increase in VE is neurally mediated, and the subsequent ...
Dempsey J A - - 1979
Three aspects concerning the role of the central nervous system in the control of exercise hyperpnea are reviewed. First, the integration of sensory input stresses the concept of multiple sites of integration--with the end result that both adequate gas exchange and near-optimal mechanical response of the lung and chest wall ...
Guillerm R - - 1979
Pulmonary function, acid-base balance, renal electrolyte excretion, hematology, biorhythms and psychomotor test results were studied in six men during 30 days of exposure to a PICO2 of 14 torr (FICO2 = 0.02) with pre- and postexposure periods on air. Alveolar and arterial PCO2 increased and remained constant throughout the CO2 ...
Swanson G D - - 1979
Practically every respiratory physiologist of the last 100 years has studied the ventilatory response to exercise. Yet we still do not know the cause of increased ventilation associated with exercise. This overview considers the problem from a broad observational point of view. Data from studies combining exercise with continuous inspired ...
Reybrouck T - - 1978
1. To study the validity of a CO2-rebreathing method at rest and during graded exercise, cardiac output was measured simultaneously on 59 occasions in 16 subjects with normal pulmonary function with the CO2-rebreathing method and the direct Fick method for oxygen. The correlation coefficient between the results of both methods ...
Sahlin K - - 1978
Eight subjects exercised on an ergometer until exhaustion. Femoral venous blood was analyzed for lactate, pyruvate, protein, electrolytes, and acid-base parameters. Muscle samples taken during the recovery period from m. quadriceps femoris were analyzed for water, electrolytes, lactate, and acid-labile CO2. Water content in the muscle biopsy sample was increased ...
Bisgard G E - - 1978
Ventilation, metabolism, arterial blood gases, and blood and cerebrospinal fluid (CSF) acid-base status were measured in exercise studies on seven ponies during mild, moderate, and near-maximal treadmill exercise. CSF and arterial blood were sampled via indwelling catheters. Generally measurements were made during the 3rd, 6th, and 9th minute of steady-state ...
Osborne J L - - 1978
Experiments on anesthetized chickens were conducted to study interactions between afferent activity from the intrapulmonary and systemic CO2-sensitive chemoreceptors in the generation of respiratory amplitude (RA) and respiratory frequency (f). The thoracoabdominal cavity was opened, air sacs ruptured and each lung independently and unidirectionally ventilated. Intrapulmonary chemoreceptor activity was altered ...
Skatrud J B - - 1978
The time course of ventilatory adaptation to medroxyprogesterone acetate (MPA) and potential mediators of this response in plasma and lumbar CSF were determined in five healthy adult males. A significant decrease in arterial PCO2 (PACO2) at rest and exercise was noted within 48 h of drug administration with the maximum ...
Anthonisen N R - - 1978
Ventilation and Pa(CO2), were measured in six subjects after 10-12 min of breathing 1-2% CO2 during hyperoxia and hypoxia. These inspired CO2 concentrations were achieved in two ways: by enriching the inspirate with CO2 and by having the subjects breathe through dead spaces of 100-400 cm3. Breathing through dead space ...
Stone D J - - 1978
A comparison of ventilatory tests and the response to carbon dioxide rebreathing was made in healthy smokers, nonsmokers, and in subjects with bronchitis. The response to carbon dioxide (CO2) rebreathing was the same in the healthy population but diminished in the bronchitic group. Effects of smoking on maximal expiratory flow ...
D'Arrigo J S - - 1978
Bubble formation in agarose gels as a result of rapid decompression following saturation with either N2, CO2, or He has been studied. Bubble number was observed to vary predominantly as a function of decompression magnitude and was virtually independent of the particular gas used. The cavitation threshold (i.e., 1 bubble ...
Young I H - - 1978
Arterial oxygen (Pao2) and carbon dioxide (Paco2) tensions and inspired minute ventilation were measured during the first 2 min of stair-climbing exercise in nine normal subjects. The subjects climbed a staircase at a rate of approximately 9 m vertical height every minute and arterial blood was drawn from an indwelling ...
Bainton C R - - 1978
We studied the effect of exercise and carotid body denervation on the ventilatory response which occurs following acute acid-base infusions. Studies were done in 6 dogs prepared with chronic tracheostomies and carotid loops. Ventilation (VE) and arterial pH were measured at rest and during exercise before and after infusions of ...
Casaburi R - - 1978
To investigate factors controlling ventilation under conditions where the applied work load remains constant, but where hypothesized proprioceptive influences would be expected to vary, five subjects exercised at a constant work rate of 50 W on a cycle ergometer at pedaling rates which varied sinusoidally between 40 and 80 rpm. ...
Sharma J D - - 1977
The cardiac-output (Q) of seven young healthy Indians with common physical characteristics at rest and after a single bout of exercise of 600 kpm for 10 min on a bicycle ergometer was ascertained by the Indirect Fick Principle. The end tidal alveolar Co2 pressure was obtained at the end of ...
Keltz H - - 1977
A method was developed to measure the oxygen cost of ventilation during CO2 rebreathing. In 20 healthy normal subjects SGaw, MMEF, and FEV1 were measured prior to and following the infusion of propranolol. In five of the same subjects airway constriction was induced by inhalation of histamine. The use of ...
Bryant M T - - 1977
Plastic syringes of 5 and 20 ml capacity of various composition were filled with either 8% CO2 in nitrogen or with 50% O2 in nitrogen. The syringes were closed with plastic stopcocks, stored on benches in a laboratory, and the gas concentrations within the syringes was measured at intervals up ...
Kronenberg R S - - 1977
We measured hypoxic and hypercapnic ventilatory drive in a 64 year old woman with acute respiratory failure, congestive heart failure and obesity when she was in remission. She had a ventilatory response to carbon dioxide (CO2) comparable to that in six obese women without hypoventilation but no ventilatory response to ...
Nishino T - - 1977
The effects, on respiration, of the acute administration of sodium bicarbonate were studied in 10 normal subjects. Carbon dioxide responses curves and tidal volume v. PCO2 relationships were obtained under hyperoxic conditions using a closed-circuit breathing system. During alkalosis, a decrease in the slope, and a displacement of the response ...
Natalino M R - - 1977
Increased body temperature stimulates hyperventilation in man but little is known about its effects on ventilatory responsiveness to hypoxia. Hence this study examined the effects of hyperthermia on hypoxic ventilatory response (HVR), hypercapnic ventilatory response (HCVR), and oxygen consumption (VO2). Six fasting subjects had these variables measured under basal conditions ...
Smolders F D - - 1977
In respiratory physiology it is often desirable to maintain the end-tidal PCO2 and PO2 at adjustable levels independent of each other, e.g., when taking steady-state CO2 or O2 response curves, or when studying the ventilatory effects of exercise or drugs at constant levels of PCO2 and PO2. Based on the ...
Chu Y K - - 1977
The Bain breathing circuit, a modified Mapleson D system, was evaluated with regard to oxygenation and CO2 elimination under controlled conditions and compared with the presently popular semiclosed breathing circuit (SCBC) with CO2 absorber. The authors demonstrated that the Bain system compares favorably with the SCBC in regard to oxygenation ...
Christensen K N - - 1977
The mean CO2 output during anaesthesia in paralyzed patients can be monitored by continuous capnographic analysis of the total exhaled gases, the latter being mechanically integrated by pumice canisters. The gas is evacuated from the Hafnia A circuit via an ejector flowmeter. The results are not influenced by the flow ...
McFadden E R ER - - 1977
The purpose of this investigation was to assess the relative contributions of hyperpnea and hypocapnia in the induction of postexercise asthma. To achieve these ends, eight young asthmatics were exercised on a treadmill while minute ventilations (VE) and end-tidal CO2 (PET CO2) tensions were continuously recorded. The subjects were then ...
Brown H V - - 1976
The ventilatory effects of beta-adrenergic blockade during steady-state exercise were studied in eight normal subjects using intravenous propranolol hydrochloride (0.2 mg/kg). Heart rate decreased in all subjects by an average of 17%. Coincident with the phase of decreasing heart rate was a significant decrease in both minute ventilation (VE) and ...
Fisher H K - - 1976
We studied 10 nonsmoking young adults before and after inducing asthmatic attacks by treadmill exercise. We used body plethysmography, flow-volume curves with air and a mixture of 80% helium and 20% oxygen, pressure-volume diagrams, and arterial blood gas analyses to characterize the effects of exercise and acute inhalation of 6% ...
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