bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of altering ventilation on steady-state diffusing capacity for carbon monoxide
Authors: Kilburn Kaye H. , Miller Harry A. , Burton John E. , Rhodes Ronald 
Published: December 2017

Alterations in the steady-state diffusing capacity for carbon monoxide (Dco) by the method of Filley, MacIntosh, and Wright, produced by sequential changes in the pattern of breathing were studied in anesthetized, paralyzed, artificially ventilated dogs. The Dco of paralyzed, artificially ventilated control dogs did not differ significantly during 3 hr from values found in conscious and anesthetized controls. A fivefold increase in tidal volume without changing frequency of breathing raised alveolar ventilation and CO uptake 500% and Dco 186%. A high correlation between tidal volume and Dco was noted during reciprocal alterations of tidal volume and rate which maintained minute volume. The Dco appeared to fall when alveolar ventilation was tripled by increments of rate with a fixed-tidal volume, despite a 63% increase in CO uptake. Doubling end-expiratory lung volume by positive pressure breathing without altering tidal volume or rate did not affect Dco. The addition of 100 ml of external dead space with rate and tidal volume constant decreased Dco to 42% of control level, however, stepwise reduction of dead space from 100 ml to 0 in two dogs failed to change Dco. Added dead space equal to frac12 tidal volume (170 ml) reduced Dco to 25% of control in two dogs with a return to control with removal of dead space. Thus, in paralyzed artificially ventilated dogs, tidal volume appears to be the principal ventilatory determinant of steady-state Dco. Dco is minimally affected by increases in alveolar ventilation with a constant tidal volume effected by increasing the frequency of breathing. Prolonged ventilation, at fixed rate and volume, and increased dead space either did not effect, or they reduced Dco, perhaps by rendering less uniform the distribution of gas, and blood in the lungs. Although lung volume was doubled by positive-pressure breathing, pulmonary capillary blood volume was probably reduced to produce opposing effects on diffusing capacity and no net change. Submitted on March 14, 1962
Determination of dissolved N2 in blood by gas chromatography and (a-A)N2 difference
Authors: Farhi L. E. , Edwards A. W. T. , Homma T. 
Published: December 2017

By combining vacuum extraction in a Van Slyke chamber and separation of the extracted gases in a gas chromatograph, it is possible to determine N2 content of 1.5 ml of blood or other biological fluids in less than 10 min. The 95% confidence limits are 0.44% on either side of the mean of the triplicate analysis-or 2.4 mm Pn2 in arterial blood when breathing room air. Application of the method to the problem of arterial-alveolar N2 difference yielded the following data: 1) N2 solubility in whole blood at 37.3 C varied from 0.0125 to 0.0129; 2) N2 solubility in urine is inversely related to urine specific gravity, confirming Klocke and Rahn's data; 3) changes in arterial N2 content were reflected in arm superficial venous blood and urine N2 only after a considerable period of time, indicating that either of these will give an excellent indication of the mean Pn2 over a period of time; 4) there is no systematic difference between venous blood and urine Pn2; 5) the (a-A)N2 difference in nine normal subjects varied from 3.7 to 13.1 mm Hg. Note: (With the Technical Assistance of M. Passke) Submitted on July 24, 1962
Change in diffusing capacity with blood flow in an improved isolated lung preparation
Authors: Rosenberg Edith 
Published: December 2017

The isolated blood-perfused cat lung preparation has been improved by using large cannulas placed so as to minimize kinking of large vessels and by reducing the pressure produced by the perfusing pump by placing resistances between it and the lung. This improved preparation was capable of accepting blood flows up to 500 ml/min for 5–10 min and could be studied for 3–5 hr before deteriorating. The diffusing capacity for carbon monoxide, Dl, was measured at various blood flows up to 500 ml/min in seven isolated lung preparations improved as indicated. A breath-holding method using a gas mixture containing 2% SF6 and 0.3% CO was employed for measuring Dl. The test gas was analyzed on a gas chromatograph. Dl increased with blood flow in all the lungs studied. In four of them which were studied at constant left atrial pressure, Dl increased steadily by 10%/100 ml increase in blood flow throughout the range studied. Pulmonary vascular resistance decreased as Dl increased. Submitted on July 12, 1962
Factors limiting depth of a maximal inspiration in human subjects
Authors: Mead Jere , Milic-Emili J. , Turner J. M. 
Published: December 2017

Simultaneous measurements of esophageal and gastric pressure during the performance of vital capacity maneuvers were made in trained and untrained normal adult subjects. The changes in transdiaphragmatic pressure from functional residual capacity to total lung capacity were found to result largely from changes in intraesophageal pressure, gastric pressure changing substantially in only two of the untrained subjects. In addition, six of the individuals were subjected to oscillating pressures during vital capacity maneuvers. Oscillatory flow at the mouth continued at maximum inspiratory levels in five of the subjects. It was concluded from these two sets of observations that antagonistic action of abdominal muscles and/or glottic closure does not limit lung expansion in most trained subjects; in these the limitations to further expansion appear to arise from the elastic recoil of the respiratory system and the diminishing effectiveness of the inspiratory muscles at high lung volumes. Submitted on July 19, 1962
Pulmonary nitrogen clearance in relation to age in healthy males
Authors: Bouhuys Arend 
Published: December 2017

Lung volumes and N2 clearance during O2 breathing were recorded in 80 healthy males, 24–65 years of age. Lung volume changes with age were similar to those found in other studies. Uneven distribution of inspired gas in the lungs as estimated from N2 clearance data showed relatively small changes with age, and the range of variability of these data was larger among the older subjects. The results suggest that impaired intrapulmonary gas distribution in older subjects is not a physiological consequence of aging, but may rather be related to long-term effects of inhaled noxious agents such as tobacco smoke. Submitted on June 11, 1962
Rate of the Bohr shift in human red cell suspensions
Authors: Craw Margot R. , Constantine H. P. , Morello J. A. , Forster R. E. 
Published: December 2017

We have measured the rate at which the O2 tension rises in a partially oxygenated suspension of normal human red cells at 37 C as a result of a sudden rise in CO2 tension (the Bohr shift) in a Hartridge-Roughton rapid reaction apparatus. A Teflon covered platinum electrode was used to measure O2 tension. The rise in O2 tension had an average half time of 0.12 sec following increments of 18–65 mm Hg in CO2 tension in twelve experiments on the blood of three normal individuals. The comparable movement of O2 out of the red cell as a result of a decrease in ambient O2 tension at a constant CO2 tension had an average half time of 0.012 sec in four experiments on the blood from the same three subjects. This suggests that the velocities of the reactions of CO2 are rate-limiting in the Bohr shift. Acetazolamide (10-3 m) slowed the rate of the Bohr shift to less than one-seventh; no measurable change in O2 tension occurred until about 0.03 sec. measurable change in O2 tension occurred until about 0.03 sec. Submitted on July 2, 1962
Changes in body temperature and basal metabolic rate of the ama
Authors: Kang B. S. , Song S. H. , Suh C. S. , Hong S. K. 
Published: December 2017

Oral temperatures of Korean diving women (ama) were measured before and after diving work in four seasons of the year. Their basal metabolic rate, measured in four seasons, was compared to that of nondiving women who lived in the same community and ate the same diet as the ama. Average oral temperatures declined to 35 C after 70 min of work in summer (water temp., 27 C) and to 33 C after 15 min of work in the winter (water temp., 10 C). Average body temperature, computed from weighted oral and average skin temperatures, declined to 34.6 C in summer and to 30 C in winter. Duration of work periods was determined principally by water temperature, since oral temperature declined at a rate inversely proportional to water temperature. The lower deep body temperatures which the ama endure in winter do, however, prolong their winter work period. The BMR of nondiving women was the same as the Dubois standard throughout the year. However, the BMR of ama varied with the season, ranging from +5 of the Dubois standard in summer to +35 in winter. We conclude that the elevated BMR of ama during the winter is cold adaptation, induced by repeated immersion in cold water. Submitted on November 23, 1962
Pulmonary function in the newborn infant: the alveolar-arterial oxygen gradient
Authors: Nelson Nicholas M. , Prod'hom L. Samuel , Cherry Ruth B. , Lipsitz Philip J. , Smith Clement A. 
Published: December 2017

The venous admixture component of the total alveolar-arterial gradient for oxygen (AaD-O2) has been measured in 26 normal infants less than 4 days of age and in 12 others with the respiratory distress syndrome (hyaline membrane disease). The AaD-O2 in normal air-breathing infants (average 28 mm Hg) is nearly three times that seen in adults. Analysis of mixing data from N2-washout curves in these infants suggests such excellent distribution of ventilation that the distribution component of the AaD-O2 must be quite small. By contrast, estimates of the shunt component during oxygen breathing reveal a shunt flow in normal infants of nearly one-fourth cardiac output (AaD-O2 = 311) which is further increased in distressed babies (up to two-thirds cardiac output) and which can completely account for the large AaD-O2's found in both groups of infants. Submitted on July 9, 1962
Pulmonary vasoconstriction in steers at high altitude
Authors: Grover Robert F. , Reeves John T. , Will Donald H. , Blount S. Gilbert 
Published: December 2017

Each of ten steers taken for 9 weeks to 12,700 ft. (Mt. Evans, Colorado) showed a marked increase in pulmonary artery (PA) pressure. Three animals had PA pressures above 90 mm Hg and one developed right heart failure. The bovine species is remarkable for the severe pulmonary hypertension which develops during chronic hypoxia rather than for an excessive PA pressure response to acute hypoxia. The rate at which the pulmonary hypertension developed at 12,700 ft. was extremely rapid compared to that at 10,000 ft. Therefore, not only the duration of the hypoxic stimulus but also its severity determine the response. The severity of the stimulus was augmented by the absence of a sustained increase in ventilation at high altitude. The pressure rise with acute hypoxia during the control period at low altitude and the dramatic fall in PA pressure when oxygen was administered at high altitude provided evidence for hypoxia-induced pulmonary vasoconstriction as an important mechanism in bovine pulmonary hypertension. Submitted on June 6, 1962
Mechanisms of cold acclimatization in the cat
Authors: Adams Thomas 
Published: December 2017

Thermoregulatory control in cats living at 25 C was compared to the regulation of body temperature in the same species after continuous whole-body cold exposure to an ambient temperature of 5 C for periods exceeding 2 months. Rectal and extremity temperatures and metabolic rates for the two groups were examined during acute (2-hr) air exposures to 23, 10, and 0 C. Cold acclimatizing mechanisms in the cat involve a redistribution of body heat at 23 C, obligating increased heat flux at the expense of elevated metabolism, an improved peripheral vascular defense (increase functional tissue insulation) during moderate cold exposure (10 C), and a greater ability to increase heat production accompanied by more labile peripheral vasomotion, during more severe cold air exposure (0 C). Although resting at 23 C, cold-acclimatized cats had lower rectal temperatures and were able to maintain higher internal body temperatures during both levels of cold stress compared to noncold-acclimatized animals. Submitted on November 1, 1962
Local muscle endurance with open and occluded intramuscular circulation
Authors: Start K. B. , Holmes Rosemary 
Published: December 2017

The local isometric endurance of the elbow flexors of four groups of five female subjects was tested. Two groups had the circulation to the contracting muscles occluded by a pressure cuff and the others had normal circulations. One group in each of the open and occluded conditions worked with a load equivalent to one-third of maximum strength and the other group worked against a resistance of two-thirds of maximum strength. The endurances of the two groups working with two-thirds of maximum strength as load were not significantly different despite the occlusion of the blood supply in one of the groups. The endurance of the group with open circulation and one-third of maximum strength as load was significantly greater than that of the group with the same load but with occluded blood supply. Only at this lower level of loading did the artificial occlusion of the blood supply to the active muscle group appear to reduce its endurance. Submitted on October 19, 1962
Calf blood flow and oxygen usage during bradykinin infusions
Authors: Coffman Jay D. , Javett Stanley L. 
Published: December 2017

The effects of continuous intra-arterial and intravenous infusion of synthetic bradykinin on plethysmographic calf blood flow and radioisotope disappearance rates from skeletal muscle, and on calf oxygen utilization in man were studied. The plethysmographic findings during intra-arterial infusion of bradykinin demonstrated a large increase in the total calf blood flow. The radioisotope disappearance rates indicated that skeletal muscle capillary blood flow was definitely involved and that bradykinin does not act on arteriovenous shunts alone. The response to continuous infusion may be transient, sustained, or intermittent, depending largely upon the dose. During continuous intra-arterial infusions of bradykinin, the oxygen utilization changes were variable but, after 5–10 min, were not statistically significant compared to control values. The lack of effect of intravenous infusion and the rapid return of flow to control levels when intra-arterial injections are discontinued confirm the rapid destruction of the endogenous polypeptide in the body. Submitted on February 7, 1963
Airway volume, airway resistance, and work and force of breathing: theory
Authors: Widdicombe J. G. , Nadel Jay A. 
Published: December 2017

Equations for optimal frequencies of breathing at which mechanical work and mean inspiratory force are minimal and which assume dead space and resistance are constant ignore possible changes in airway caliber. We assumed an inverse relationship between resistance and dead space and plotted a series of curves relating mechanical work and mean inspiratory force to frequency of breathing for various dead spaces and corresponding resistances. As dead space increases, the levels of work and inspiratory force fall to minima, then rise; the frequencies at which work and force are minimal increase, then decrease. Adding a series resistance or dead space, changing the resistance/dead space relationship, decreasing lung compliance, or increasing alveolar ventilation do not alter the general shapes of the curves, but change the values of optimal dead space. The optimal dead spaces for minimal work (0.125 liter) and for minimal inspiratory force (0.14 liter) lie within the normal range. Nervously mediated airway tone in healthy subjects may represent optimal adjustment of airway caliber. dead space, optimal; bronchial caliber Submitted on October 26, 1962
Acid-base changes in the fetal lamb before and after lung expansion
Authors: Assali N. S. , Manson W. A. , Holm L. W. , Ross M. 
Published: December 2017

The acid-base status of the fetal lamb was studied in near-term pregnant ewes subjected to spinal anesthesia. The status of the fetus was compared to its mother and the changes which occur after the fetal lungs were ventilated with oxygen or nitrogen were investigated. The results show that: 1) the fetus in utero is in a state of metabolic acidosis in relation to the mother, 2) the acidosis does not seem to be related to the fetal blood pCO2, and 3) the acidosis may be aggravated by hypoxia. fetal acidosis; blood pH; blood oxygen; blood carbon dioxide; hypoxia; hyperoxia; sheep Submitted on March 20, 1963
Oxygen washout studies in the anesthetized dog
Authors: Cater D. B. , Hill D. W. , Lindop P. J. , Nunn J. F. , Silver I. A. 
Published: December 2017

To evaluate technique for producing hypoxia in patients during radiotherapy, anesthetized dogs were hyperventilated with N2 for 3 min. End-tidal Po2 fell rapidly to near zero, but arterial Po2 fell to 10 mm Hg with mixed venous Po2 fractionally higher. Mean tissue Po2 of cortical gray matter fell to 0.7 mm Hg, white matter to 1.7, and subcutaneous tissue to 1.8, but muscle fell only to 7.8 mm Hg. Reasons for failure of oxygen washout are discussed. N2 inhalation; radiosensitivity; muscle Po2; brain Po2; tissue Po2; polarography; cerebral cortical cell inhibition; arterio-venous Po2 Submitted on October 25, 1962
Basal oxygen uptake of man at high altitude
Authors: Grover Robert F. 
Published: December 2017

When man native to low altitude is exposed to altitudes in excess of 10,000 ft, is there a change in his basal oxygen uptake? This question was prompted by the unexpected observation of a 20% decrease in resting oxygen uptake of cattle and lambs at high altitude. To elucidate this problem in man, multiple determinations of basal oxygen uptake were made on six individuals, at both 5,200 and 14,150 ft. A small but significant increase in oxygen uptake was observed, probably reflecting the energy required to increase ventilation. Note: With the Technical Assistance of Estelle B. Grover and Janet K. Hagerma Submitted on March 11, 1963
Pulse count as a measure of energy expenditure
Authors: Malhotra M. S. , Gupta J. Sen , Rai R. M. 
Published: December 2017

Studies were made on seven subjects who were given different grades of exercise on a bicycle ergometer with a workload varying from 50 to 600 kg-m/min. Calorie expenditure during performance of various tasks was calculated by collecting the expired gases during the steady state. Pulse rate was also recorded during this period. To estimate the error in using pulse rate for measuring energy expenditure, the same subjects were given various field tasks such as marching, running, hopping, hammering, etc. During performance of these tasks energy expenditure and pulse rate were also measured, using the same techniques. Linear correlation was obtained between the pulse rate and the energy expenditure in all the subjects. There are two components of each curve, one for the pulse rates below 95 and the other for pulse rates above 95. A significant difference also was found in the coefficient of variation for different subjects, showing that separate regression lines are required for each of them. The percentage of error between observed and predicted values of energy expenditure for both the ranges of pulse counts varied from 0.3 to 4.7 and from 0.6 to 7.0, respectively. Submitted on July 30, 1962
Effects of fever on pulmonary diffusing capacity and pulmonary mechanics in man
Authors: Cander Leon , Hanowell Ernest G. 
Published: December 2017

Measurements of oral temperature, pulse rate, blood pressure, expired minute volume (Ve), respiratory rate (f), O2 consumption (Vo2), CO2 excretion (Vco2), breath-holding pulmonary diffusing capacity (DlCO), dynamic pulmonary compliance (Cdyn), and total pulmonary resistance were made on six normal adults before and at regular intervals over an 8-hr period following the induction of fever with triple typhoid vaccine. Although Ve, f, Vo2 increased during the chill, flush, and defervescence phases of fever, there was no significant change in Cdyn and total pulmonary resistance. Of interest was the slight, though statistically significant decrease in DlCO during the flush and defervescence phases. Results suggest a low temperature coefficient for the mechanical properties of the lung in the range studied. The absence of an increased DlCO during the flush phase of fever when Ve and the cardiac output are known to increase suggests that ventilation and pulmonary blood flow are not important determinants of DlCO. lung mechanics; ventilation Submitted on February 18, 1963
Distribution of inspired gas during anesthesia and artificial ventilation
Authors: Bergman Norman A. 
Published: December 2017

Distribution of inspired gas was compared during spontaneous ventilation in the conscious state, during spontaneous ventilation in the anesthetized state, and during artificial ventilation in the anesthetized, paralyzed state in nine human subjects. Uniformity of distribution of inspired gas was measured using an open-circuit nitrogen-washout method. Rate and pattern of nitrogen elimination during oxygen breathing as well as calculated indices of uniformity of distribution of inspired gas and efficiency of over-all pulmonary ventilation did not vary significantly among the three conditions studied. Induction of anesthesia or substitution of artificial ventilation for spontaneous ventilation, therefore, caused no detectable change in uniformity of distribution of inspired gas. intrapulmonary mixing; respiratory changes during anesthesia Submitted on January 24, 1963
Measurement of ventilation/perfusion distribution with alveolar-arterial differences
Authors: Lenfant C. 
Published: December 2017

The alveolar-arterial difference A-aD for Po2, Pco2, and Pn2 have been measured at a number of FiOO2. When FiOO2 was raised from .2 to .4 A-aDo2 and A-aDn2 increased and remained at the same level for any further rise of FiOO2. A-aDco2 did not seem to be affected by the FiOO2 change. In young healthy subjects, mean A-aDo2 reached 30 mm Hg and A-aDn2 8 mm Hg. In a group of older or diseased subjects these values were 55 and 18 mm Hg, respectively. In both groups the A-aDco2 was due to overventilated alveoli among the predominant type of alveolus. Alveoli of the predominant type seem to have a mean ventilation/perfusion ratio (Va/Q) close to the over-all mean value. The increases in A-aDo2 and A-aDn2 at high FiOO2 show the presence of a smaller group of alveoli having a very low, if not undeterminable, Va/Q ratio. The size of A-aDn2 as compared to the size of A-aDo2 proves that the real anatomical shunt is not as large as has been thought from measurement of the A-aDo2 alone. At least 38–45% of the total A-aDo2 is caused by very poorly ventilated alveoli. pulmonary shunts; gas partial pressures in blood Submitted on March 8, 1963