bluuebunny/crossref_metadata_2025 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
Hypoxic-hypercapnic interaction in subjects with bilateral cerebral dysfunction
Authors: Plum Fred , Brown Harold W.
Published: December 2017

To analyze cerebral influences modifying autonomic respiratory responses, we compared normals and patients with bilateral pyramidal tract disease for their ventilatory response to hypoxia and hypoxia-hypercapnia. During eucapnia, the two groups showed similar hypoxic responses. During hypercapnia, the ventilatory response to hypoxia was greater in the brain-damaged subjects. This apparent augmentation, however, was due entirely to anoxia interacting with an abnormally facilitated carbon dioxide sensitivity: compared with normals, brain-damaged patients at PaOO2 90–100 mm Hg showed an 85% greater CO2 response, and at PaOO2 50 mm Hg showed a 79% greater CO2 response. Since cerebral dysfunction facilitated the ventilatory response to hypoxia-hypercapnia combined but not the response to hypoxia alone, the results imply that the two respiratory stimuli interact centrally rather than peripherally.

respiration; brain damage; interaction; carbon dioxide response; forebrain effects; ventilation with CNS disease

Submitted on February 18, 1963
Effect of a fatty meal on whole blood and plasma viscosity
Authors: Charm S. , McComis W. , Tejada C. , Kurland G.
Published: December 2017

The viscosity of whole blood of 40 medical students measured with a Brookfield cone and plate viscometer showed no change before and after a fatty meal although the serum lipids increased. In separate experiments, no change was noted in plasma viscosity as determined by the capillary tube technique although plasma lipids increased. From theoretical considerations, it was suggested that methods of determining viscosity within a 2% error would be necessary in order to detect changes in plasma and whole blood viscosity after a fatty meal. However, even with the GDM low-shear rate coaxial viscometer, which has an accuracy reputed to be 2%, no change was observed in the whole blood or plasma viscosity. The results with the GDM viscometer compared favorably with the results from the Brookfield cone and plate viscometer. In 2 out of 52 cases a definite decrease in whole blood viscosity was found 3 hr after a fatty meal. The plasma viscosities, however, did not change. It is postulated that in rare cases a decrease in the yield stress of the cell aggregates due to the increased lipids results in a decreased blood viscosity. The mechanics by which this occurred is under study.

dietary fat; viscosity of blood

Submitted on June 15, 1963
Steroid and catecholamine studies on pilots during prolonged experiments in a space cabin simulator
Authors: Ulvedal F. , Smith W. R. , Welch B. E.
Published: December 2017

Urinary excretion of 17-hydroxycorticosteroids, corticosterone-like hormones, and catecholamines (epinephrine and norepinephrine) has been investigated on pilots during prolonged experiments in a two-man space cabin simulator. The experimental profiles were: 1) two 17-day experiments at ground level; 2) two 14-day experiments at 27,000 ft; and 3) four experiments at 33,500 ft lasting 17 days. In the latter two groups the atmosphere was essentially 100% O2. The hormone parameters indicate that conditions imposed by the experimental procedures were no more stressful to the subjects than undergoing extensive medical examinations as observed from pre- and postexperimental values. The only significant trend was the continuous linear increase in the excretion of corticosterone-like hormones. There were borderline indications that the excretion of 17-hydroxycorticosteroids and norepinephrine were altitude dependent. Extraordinary occurrences in the simulator were correlated with increased catecholamine and steroid excretion. The correlation coefficients and the analyses of variance for the four hormone parameters were calculated and discussed.

endocrinology; sealed environments; stress hormones

Submitted on March 26, 1963
Apparatus for determination of zeta potentials from streaming potentials
Authors: Beck R. E. , Mirkovitch V. , Andrus P. G. , Leininger R. I.
Published: December 2017

A system was developed to measure the streaming potential generated between the ends of a capillary by the flow of a fluid through the capillary. Zeta potential can be calculated from the streaming potential. Adequate sensitivity and reproducibility were achieved by making special electrodes: silver wires plated in KCl solution and embedded in agar, careful electrical shielding, and provision for reversal of flow through the capillary to minimize electrode errors. The apparatus was developed to measure streaming potentials generated by either RingerS's solution or blood in contact with capillaries made of different materials such as quartz, polyethylene, etc. An example of a determination using a quartz capillary is presented.

interfaces; blood; salt solutions; glass; quartz

Submitted on February 25, 1963
Volumetric dynamics of respiration as measured by electrical impedance plethysmography
Authors: Allison R. D. , Holmes E. L. , Nyboer J.
Published: December 2017

Electrical resistive impedance changes of the chest related to pulmonary air volumes were quantitatively evaluated in ten normal male adults. A four-electrode, 100-kc, electrical impedance plethysmograph was used for these determinations. A 13.5-liter Collins respirometer was used to measure changes in pulmonary gas volume. In all studies reported the electrodes were positioned on the posterior aspect of the thorax. The current was delivered to the outer pair with one attached to the neck and the other below the level of the diaphragm. The voltage drop related to variations in resistance was detected between the inner two electrodes at a constant length of 30 cm. Inspiration and expiration were associated with changes in electrical resistive impedance. Calculations of changes in pulmonary gas volumes were based on electrical variations associated with respiration. The calculated values closely approximated recorded volumes on the spirometer for values of 100–2,500 ml. This technique would eliminate carbon dioxide absorbents, nose clips, conventional airway hindrances and have adequate frequency response for a normal range of test conditions. Some of the limitations in the practical application of the system currently under study are discussed.

pulmonary air volume determination; resistive impedance; measurements of the chest; pulmonary function; respiration

Submitted on April 17, 1963
Minimal air in dogs
Authors: Kleinman Leonard I. , Poulos Dennis A. , Siebens Arthur A.
Published: December 2017

The “minimal air” of supine dogs was measured by subtracting from the functional residual capacity the volume expelled from the lungs when the sternum was widely split. Minimal air/functional residual capacity, minimal air/lung weight, and minimal air/animal weight were 57.0 ± 8.6%, 9.51 ± 2.92 ml/g, 21.8 ± 4.2 ml/kg, respectively. The correlation coefficient of minimal air with functional residual capacity was .79 (P < 1%), of minimal air with animal weight was 0.70 (P < 1%), and of minimal air with lung weight was .67 (P < 5%). The ratio minimal air/functional residual capacity of these dogs compared with the ratio residual volume/functional residual capacity of supine men. The airway component of the minimal air was approximately 36% and the alveolar component approximately 64%. The lungs contained the minimal air at a time when airways were patent rather than collapsed.

functional residual capacity; residual volume

Submitted on March 11, 1963
Effect of temperature on arterial blood gas tensions and pH during exercise
Authors: Holmgren Alf , McIlroy Malcolm B.
Published: December 2017

We measured arterial blood Po2, Pco2 and pH at rest and during a standard exercise test on a bicycle ergometer in ten normal subjects. In five we measured esophageal and five arterial blood temperature during the exercise and corrected the arterial blood values to the temperature at the time the samples were collected. We found an average rise in temperature of 1 C (range 0.2–1.6 C) during exercise lasting about 30 min at loads up to an average of 1,200 kg-m/min. At the highest load the average correction for PaOO2 was 5.6 mm Hg, for PaCOCO2 1.6 mm Hg and for pH 0.014 units. Our corrected values showed a fall in PaCOCO2 and pH and a rise in PaOO2 during severe exercise. These findings are compatible with the development of a metabolic acidosis during severe exercise and indicate that our subjects were not limited by diffusion across the alveolar-capillary membrane.

metabolic acidosis; alveolar capillary membrane diffusion; hyperventilation; PaOO2 and PaCOCO2 in severe exercise

Submitted on June 17, 1963
Mechanical work in running
Authors: Cavagna G. A. , Saibene F. P. , Margaria R.
Published: December 2017

The external and internal mechanical work in running has been measured through various procedures. Different from walking, in running the work due to the forward speed changes (variation of kinetic energy) and to the vertical displacement of the center of gravity (variation of potential energy), throughout the step cycle, are substantially in phase. The external work performed per kilometer is independent of speed, amounting to 0.25 kcal/kg km. The total mechanical work amounts to about 0.40–0.50 kcal/kg km. The efficiency in running has been calculated as about 40–50%: such a high value involves a contribution of a substantial amount of energy delivered at a very low cost; this appears to be identified as elastic recoil energy from the stretched contracted muscle and amounts to about half the energy spent in running. A mechanical model is given for the walking and running processes.

mechanics of locomotion; kinetic and potential energy during step cycle; elasticity of contracted muscle; mechanical models for walking and running

Submitted on July 29, 1963
Cytology of human bone marrow subjected to prolonged storage at -79 C
Authors: Pegg D. E.
Published: December 2017

It was observed that human bone marrow cells preserved at -79 C with 15% glycerol exhibited marked morphological changes when examined by conventional cytological methods, and that techniques designed to remove glycerol slowly produced still more damage. By contrast, cells from which the glycerol was removed rapidly by abrupt dilution in an isotonic medium were found to be morphologically intact when examined on cellulose acetate membrane filters: the quantitative recovery was 74%, and undoubted proof of viability was provided by the demonstration of motile cells. When bone marrow was examined after storage for periods up to 3 frac12 years it was noted that a progressive loss of cells occurred, and a variety of cytological techniques, including staining by Romanowsky, Feulgen, PAS, Sudan black, and pyronin techniques and supravital staining with acridine orange and trypan blue all provided further evidence of progressive deterioration during storage at -69 to -79 C.

human bone marrow preservation; human bone marrow viability; cryobiology

Submitted on May 20, 1963
Determination of tissue volume and carbon dioxide dissociation slope of the lungs in man
Authors: Sackner Marvin A. , Feisal Khalil A. , DuBois Arthur B.
Published: December 2017

The volume of N2O absorbed by the lung can be measured during inspiration before the gas is taken up in significant amounts by the capillary blood flow by a plethysmographic technique. If the alveolar fraction of N2O and its solubility coefficient are known, the combined pulmonary tissue and capillary blood volume (Vt+c) can be calculated. Vt+c averaged 517 ml, sd 61 ml, in nine adult males, values in good agreement with those obtained by other methods. The pulmonary tissue volume alone, Vt, in six of these subjects was 438 ml, sd 58 ml. A modification of the technique, using CO2 as the test gas, permitted calculation of the CO2 dissociation slope of the lung tissue. In five subjects, the CO2 dissociation slope of the lung, without the buffering effect of pulmonary capillary blood, over a range of PaCOCO2 from 31 to 55 mm Hg, averaged 0.30 ml CO2 STPD/100 ml lung tissue per mm Hg, or including physically dissolved CO2, 0.38 ml CO2 STPD/100 ml lung tissue per mm Hg. Because Vt is about four times larger than Vc, the lung tissue is of greater importance than the pulmonary capillary blood in buffering fluctuations in alveolar carbon dioxide during respiration.

pulmonary tissue volume; pulmonary tissue space for N2O

Submitted on August 26, 1963
A radio telemetering device
Authors: Barry William
Published: December 2017

A radio telemetering device is presented in detail and successful operation in transmitting the electrocardiogram of the freely moving human subject at ranges up to 200 yards is claimed. The linear nature of its frequency response will permit quantitative rather than qualitative investigations to be made of any physiological variable when this transmitter unit is used with the appropriate transducer.

radio-transmitted ECG signals; portable ECG; biologic amplifiers; electronic ECG recording

Submitted on August 19, 1963
Fashioning polyethylene tubing for use in physiological experiments
Authors: Heatley Norman G. , Weeks James R.
Published: December 2017

Working instructions are given, with diagrams, for simple methods of joining, bending, sealing, and reinforcing fine plastic tubing, chiefly of polyethylene; for making it larger or smaller, for fabricating cannulas, T pieces, and multiway junctions; and for connecting it to other pieces of apparatus.

physiological techniques using polyethylene tubing; polyethylene tubing, physiological uses; tubing, polyethylene, fashioning techniques; methods, physiological, using polyethylene tubing; physiology, laboratory techniques for polyethylene tubing

Submitted on November 8, 1963
Cerebral hematocrit in normal man
Authors: Larsen O. Andrée , Lassen Niels A.
Published: December 2017

The cerebral mean circulation times of plasma and erythrocytes and the cerebral hematocrit were determined by injection of I131-labeled albumin and Cr51-labeled erythrocytes into an antecubital vein, drawing multiple blood samples simultaneously from the carotid artery and the internal jugular vein, and calculating the arteriovenous concentration differences. The total body hematocrit was determined from equilibrium concentrations. In ten normal subjects the average cerebral hematocrit was 92.2% of the large vessel hematocrit, this difference being highly significant (P < 0.001). The total body hematocrit averaged 88.6% of the large vessel value and was significantly lower (P < 0.01) than for the brain. As the cerebral vascular bed has protein-tight capillaries, it is concluded that this area contains an extra plasma volume inside the vessel walls. It is suggested that the oft-repeated finding of a body hematocrit of about 90% of the large vessel hematocrit is mainly due to excess intravascular plasma localized to all the minor vessels in the body.

cerebral mean circulation time; cerebral blood volume; body hematocrit

Submitted on January 6, 1964
Effect of exercise on free fatty acid levels in the pigeon
Authors: George J. C. , Vallyathan N. V.
Published: December 2017

The effect of exercise on the free fatty acid (FFA) levels in the muscle, liver, adipose tissue, and blood in the pigeon was quantitatively studied after the electrical stimulation of the breast muscles. A reduction of FFA in the blood plasma, liver, and adipose tissue was observed after the stimulation of the muscle. On the other hand, an increase in the FFA content of the muscle was noticed. It was found that there is high rate of FFA extraction by the muscle from the blood which in turn is being supplied from the adipose tissue and liver during the activity of the muscle. From the data obtained it is concluded that the skeletal muscles of birds utilize mainly fat during sustained muscular activity. The physiological importance of FFA as substrate for muscular activity is discussed.

fat utilization by muscle; fatty acid release from adipose tissue and liver; blood lipid level in exercise

Submitted on September 25, 1963
Blood-gas transfer, hemolysis, and diffusing capacity in a bubble tonometer
Authors: Ravin Mark B. , Briscoe William A.
Published: December 2017

The performance of a test-tube tonometer is described. The 95% equilibration times in 10 ml blood are 2.9 and 14 min, respectively, with small and large bubbles at a bubble flow rate of 1 ml/sec. Small bubbles have the disadvantage that surface tension significantly raises gas pressure above atmospheric. With large bubbles surface tension effects are negligible and hydrostatic pressure is only about 0.5% of an atmosphere. Hence, large bubbles are preferred for calibrating an oxygen electrode for use with blood of a high Po2. Hemolysis produces less than 150 mg/100 ml plasma hemoglobin in the time needed for equilibration. The diffusing capacity for oxygen of the bubble interface in 10 ml blood in the tonometers is about 0.001 and 0.008 ml mm-1 sec-1 with large and small bubbles, respectively, when blood Po2 is about 20 mm Hg, and is one-tenth as much when blood Po2 is over 500 mm Hg. This type of tonometer appears to be a useful adjunct to the oxygen electrode.

oxygen; equilibration

Submitted on July 1, 1963
Relationship of changing bronchial caliber to respiration in the dog
Authors: Colgan Frank J.
Published: December 2017

A cylindrical bronchial catheter is described for recording moment-to-moment changes in caliber during spontaneous respiration in lightly anesthetized dogs. Caliber changes due to bronchial transmural pressure and altered bronchial tone are measured separately and collectively. Transmural pressure changes, because of the elastic character of bronchi, are shown to alter caliber significantly. Histamine-induced alterations in bronchial tone are capable of dominating transmural pressure influences on caliber. Following small doses of intravenous histamine, dynamic compliance decreases progressively and the decrease is related in time and degree to changes in bronchial caliber. Recovery is prompt and sustained. Decrease in compliance occurs without significant increase in airway resistance or change in functional residual capacity. These observations suggest that a dominant factor influencing dynamic compliance is alteration of bronchomotor tone.

bronchial distensibility; bronchoconstriction; bronchomotor tone; transbronchial pressure; compliance; mean airway resistance; histamine Mecholyl

Submitted on January 6, 1964
An isothermal system for manometric measurement of changes of volume
Authors: David A. , Greenfield M.
Published: December 2017

The volume of gas to be measured is displaced into a reservoir which is so constructed that its contents undergo nearly perfect isothermal compression, raising the pressure by up to 1 mm Hg relative to the pressure in an identical compensating reservoir. The conditions of compression ensure a stable calibration over a wide range of rates of gas displacement, and the use of a compensating reservoir makes the system quite independent of fluctuations in barometric pressure, and largely independent of fluctuations in ambient temperature.

volume recorder; air displacement recorder; barometric measurement of volume

Submitted on December 9, 1963
Vestibular habituation during repetitive complex stimulation: a study of transfer effects
Authors: Guedry Fred E. , Collins William E. , Graybiel Ashton
Published: December 2017

Thirty-two men were rotated at 7.5 rev/min while facing the center of the Pensacola slow rotation room for several hours. The men were seated 4 ft from the center of rotation; direction of rotation was toward the subject's left. During rotation, subjects were immobile except for series of measured head movements restricted to the frontal plane and to a particular quadrant of that plane for each subject. Nystagmus, illusory phenomena, and nausea were reduced by this procedure, but this habituation did not transfer to other forms of vestibular stimulation including that induced by head movements in an “unpracticed” quadrant of the same plane. Residual effects exhibited in “static tests” after the habituation program were primarily restricted to the practiced quadrant.

habituation; nystagmus; vestibular function

Submitted on January 15, 1964
Heart rate during transition from rest to exercise, in relation to exercise tolerance
Authors: Davies C. T. M. , Harris E. A.
Published: December 2017

Thirty-four healthy subjects of different ages and sex have been studied during exercise on a motor-driven treadmill. Heart rate was measured continuously, oxygen consumption was measured during the steady state of exercise, and in 15 subjects the maximum oxygen consumption was also determined. From these data three standard indices of working capacity were calculated, together with an index based upon the "pulse deficit" of early exercise, for comparison with each other and with the maximum oxygen consumption. The "pulse deficit index" was found to express relative working capacity slightly better than any of the standard indices.

working capacity and heart rate; pulse deficit of exercise

Submitted on November 19, 1963
Physiological reactions to heat of Bushmen and of unacclimatized and acclimatized Bantu
Authors: Wyndham C. H. , Strydom N. B. , Ward J. S. , Morrison J. F. , Williams C. G. , Bredell G. A. G. , Von Rahden M. J. E. , Holdsworth L. D. , Van Graan C. H. , Van Rensburg A. J. , Munro A.
Published: December 2017

Bushmen in the Kalahari desert fulfill two criteria for acclimatization to heat. They exercise actively, in hunting, in relatively severe heat in midsummer. Compared with unacclimatized Bantu they have higher sweat rates per square meter and lower heart rates. However, rectal temperatures are not much lower than those of unacclimatized Bantu. River Bushmen present a paradoxical picture. In summer sweat rates are higher than in winter, but are not as high as desert Bushmen. Summer heart rates are, however, higher than in winter. Rectal temperatures in the two seasons are similar. The higher sweat rates in summer are good evidence of better acclimatization than in winter; the higher heart rates may be a reflection of differences in physical fitness in the two seasons.

association of morphology and metabolism on cold exposure; cold responses of Bantu, Bushmen, and Caucasians; heat conductance and skinfold thickness in cold; metabolisms of Bantu, Bushmen, and Caucasians in cold; toe, finger, and rectal temperatures of different ethnic groups in cold

Submitted on February 4, 1964
Influence of temperature on blood pH of the human adult and newborn
Authors: Adamsons Karlis , Daniel Salha S. , Gandy Gillian , James L. Stanley
Published: December 2017

The effect of temperature upon pH of blood from adult and newborn humans was investigated. Although the mean ΔpH/ΔT values for the two populations differed, 0.0144/ °C for adults versus 0.0128 for the newborn, this was not peculiar to the source since the temperature-induced pH changes were identical when comparison was made between samples of similar pH and CO2 content. It was shown that even over the physiologic pH range ΔpH/ΔT is not constant but is a function of pH and CO2. No significant changes in ΔpH/ΔT were observed with oxygenation of hemoglobin. The influence of red cell concentration was detectable only when hematocrit values fell below 20%. A graph and an equation for the determination of ΔpH/ΔT of blood with a given pH and CO2 content is presented.

acid base

Submitted on December 9, 1963
Heat exchange in men and women following intravenous injection of endotoxin
Authors: Buskirk E. R. , Thompson R. H. , Rubenstein M. , Wolff S. M.
Published: December 2017

An assessment was made of heat exchange during the course of an induced febrile episode following injection of endotoxin. Experiments were performed on either normal subjects or patients with recurrent fever. They were given intravenously either saline or a dose of 1 or 2 mμg Lipexal (the lipopolysaccharide of Salmonella abortus equi) per kilogram approximately 15 min before being exposed for 3–6 hr to 27.7 C air while wearing minimal clothing. Continuous measurements were made of: oxygen consumption, carbon dioxide production, core temperatures, skin temperatures, muscle surface temperature, and heat flow from the lateral surface of the upper and lower arm and the back of the hand. Three distinct patterns of reactivity were found: a) nonreactors (N = 2), b) those in whom elevated heat production preceded a rise in core temperature (N = 8), and c) those in whom thermal redistribution produced a rise in core temperature prior to an increase in heat production (N = 5). The results suggest that endotoxin may produce fever by alteration of either vasomotor control of heat redistribution or heat production at independent rates. Fever patients, in comparison to normal subjects, appeared to have an exaggerated metabolic response per equal increment in core temperatur

Note

(With the Technical Assistance of D. Thrasher)

cold; fever; temperature regulation

Submitted on December 23, 1963