bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in alveolar and arterial gas tensions as related to altitude and age
Authors: Terman James W. , Newton Jerry L. 
Published: December 2017

In the summer of 1962 at the White Mountain Research Station the early phases of altitude acclimatization were studied in six of the surviving eight members of the 1935 expedition to the Chilean Andes; they were from 58 to 71 years of age. Alveolar and arterial Po2 and Pco2 were determined for each man a few hours after arrival at 3,093 m and at 3,800 and 4,343 m over the next few days. The effects of age were superimposed on the classical responses to high altitude. The arterial and alveolar Pco2 values showed no significant gradient; the alveolar Pco2 was found to be lower for a given altitude than 27 years before. For example, their average alveolar Pco2 at 4,700 m in 1935 was 27.7 mm Hg as opposed to 25.1 mm Hg at 4,343 m in 1962. The case of Hall was exceptional: his alveolar Pco2 ranged from 21 to 24 mm Hg regardless of altitude for his sojourn of 22 days. In 1935 these six men had a mean A-a Po2 gradient of +3.0 mm Hg at 4,700 m, while in 1962 the gradient over the three altitudes was +12.4 mm Hg. These findings would likely be explained partially by age changes in the pulmonary ventilation-perfusion ratio. acclimatization; pulmonary ventilation-perfusion ratio; alveolar-arterial Po2 and Pco2 gradients; alveolar hyperventilation; aging and altitude Submitted on February 19, 1963
Topography of esophageal pressure as a function of posture in man
Authors: Milic-Emili J. , Mead J. , Turner J. M. 
Published: December 2017

Esophageal and mouth pressures were determined at various fixed lung volumes in seven normal subjects in various postures. Esophageal pressure was obtained from balloons placed at various levels of the esophagus. The balloons contained a volume of gas small enough to render its effect on the pressure recorded negligible. In approximately the upper third of the esophagus changes in mouth pressure, head posture, and external pressure on the trachea produced pressure variations which were unrelated to variations in pleural pressure and were probably the result of traction on, or compression of, the esophagus by the trachea. These artifacts were absent in the lower two-thirds of the esophagus. In the lower third of the esophagus, pressures were found to vary markedly from point to point and with body posture. In approximately the middle third of the esophagus pressures were relatively uniform from point to point, did not vary markedly with body posture, and probably more closely reflect local pleural pressures. It is concluded that in studies of respiratory mechanics esophageal pressure should be measured in the middle third of the esophagus. pleural pressure; lung volume-pressure curves; esophageal balloons Submitted on August 13, 1963
Thrombin stimulation of platelet oxygen consumption rate
Authors: Hussain Qamar Zafar , Newcomb Thomas F. 
Published: December 2017

Oxygen consumption of human platelets was measured by O2 cathode. Platelets were prepared by collecting blood into ACD solution, and isolation and washing in buffer by centrifugation. O2 consumption was measured by vibrating cathode at 25 C in Hank's solution. The Qo2 was 14.5 ± 4.8 mμmoles/min 109 platelets with added glucose and 21.4 ± 5.0 with added glycerol. Thrombin addition resulted in increase in Qo2 of elevenfold lasting 3–5 min followed by clumping of the platelets. EDTA blocked the thrombin effect. Similar effects were noted when prothrombin was activated to form thrombin. 5-Hydroxytryptamine was without effect. With EDTA the reaction had two phases, a phase of thrombin effect and a calcium-dependent clumping phase. The observations are compatible with the hypothesis that thrombin alters platelet permeability. platelet clumping; viscous metamorphosis of platelets; platelet respiration measurement by O2 cathode; thrombin effect on platelet respiration; platelet respiration; platelet intermediary metabolism Submitted on September 20, 1963
Cerebrospinal fluid in man native to high altitude
Authors: Severinghaus J. W. , B. A. Carceleń 
Published: December 2017

CSF pH was shown in a prior report to remain essentially constant during 8 days of acclimatization to 3,800 m. In order to further evaluate the possible role of CSF acid-base equilibria in the regulation of respiration, 20 Peruvian Andean natives were studied at altitudes of 3,720–4,820 m. In ten subjects at 3,720 m, means were: CSF pH 7.327, Pco2 43, HCO3- 21.5, Na+ 136, K+ 2.6, Cl- 124, lactate 30 mg/100 ml. Arterial blood: pH 7.43, Pco2 32.5, HCO3- 21.3, Na+ 136, K+ 4.2, Cl- 107, hematocrit 49, SaOO2 89.6. In six subjects at 4,545 m and four at 4,820 m CSF values were not significantly different; mean arterial Pco2 was 32.6 and 32.3, respectively. The only significant variations with altitude were the expected lowering of PaOO2 to 47 and 43.5 mm Hg, and of SaOO2 to 84.2 and 80.7, and increase of hematocrit to 67% and 75%, respectively. The natives differed from recently acclimatized sea-level residents in showing less ventilation (higher Pco2) in response to the existing hypoxia, and less alkaline arterial blood. The difference appears to relate to peripheral chemoreceptor response to hypoxia rather than central medullary chemoreceptor. respiratory regulation at high altitude; chronic acclimatization to altitude; peripheral chemoreceptor response to hypoxia; CSF and medullary respiratory chemoreceptors Submitted on June 12, 1963
Surface activity of saline extracts from inflated and degassed normal lungs
Authors: Levine Bernard E. , Johnson Rudolph P. 
Published: December 2017

Normal rabbit lungs have been extracted in aerated and in vitro degassed states to clarify the effect of atelectasis upon the surface activity of saline lung extracts. Three extraction techniques, chopping, mincing, and pestle-homogenization, were compared. All extraction methods give highly active extracts using aerated lung samples, but extracts from airless lungs prepared by chopping or mincing invariably showed higher minimum surface tensions, lower stability indices, and took more time to reach minimum tension than did extracts of the same lungs when aerated. Differences could be due to decreased area of saline-alveolar contact during extraction, as it was noted that increasing the weight of the lung sample or dividing the lung more finely (i.e., pestle homogenization) increased extract activity. If saline extracts of atelectatic lung are studied, qualitative statements about presence of surfactant should take into account weight of lung tissue and technique of extraction. lung surface tension; atelectasis; pulmonary surfactant material; rabbit lung surface activity Submitted on September 11, 1963
Use of an optical density ruler in measurements of dye-dilution curves
Authors: Bassingthwaighte James B. , Edwards Anthony W. T. , Wood Earl H. 
Published: December 2017

The inapplicability of Beer's law to densitometry of dyes in whole blood or other nonhomogeneous media has been long known. When using a densitometer whose output is directly proportional to the light transmitted, a simple transformation— log X = log (x – x0)—can be employed to allow rapid, accurate estimation of dye concentration. This is facilitated by use of an optical density ruler. The transformation, X = x – x0, can be made mechanically, by shifting the infinity position of the ruler with reference to the zero light transmission position, or electrically, by appropriate use of zero suppression in the densitometer circuit. The transformation results in an exponential (logarithmic) relationship between light transmitted and concentration of the dye (indocyanine green). Readings of relative optical density obtained by use of the ruler are multiplied by a calibration constant to calculate dye concentration. The principles of the transformation have been applied to the determination of the optimal zero suppression required for maintenance of constant sensitivity of the densitometer in the presence of various levels of background dye. densitometer calibration; indocyanine green densitometer; calibration of dye-dilution curves; correction of dye-dilution curves Submitted on September 13, 1963
Effect of vasoconstriction on galvanic skin response amplitude
Authors: Edelberg Robert 
Published: December 2017

Vascular mediation of the effect of cooling on galvanic skin response (GSR) amplitude was investigated by maintaining a finger site under isothermal conditions while inducing reflex vasoconstriction by cooling the rest of the hand in a water bath at 15 C. This procedure caused an initial increase in GSR amplitude, relative to that on the opposite (control) hand, followed by a steady decline to levels significantly lower than normal. Base resistance was generally unaffected. Smaller GSR waves frequently showed a paradoxical increase in size at the same time as larger ones were attenuated. In control runs in which the insulated chamber acted as a calorimeter the fall of temperature occasioned by arterial occlusion of the finger was of the same order as that produced by cooling. Arterial occlusion accompanying cooling did not change the temperature drop and it was concluded that a cooled blood supply could not account for the observed effects. Rather they appear to depend on cutaneous vasoconstriction. This conclusion implies an artificial relation between vasomotion and GSR as autonomic measures whenever pronounced vasoconstriction occurs. effect of vasoconstriction on skin resistance; temperature effect on skin resistance; temperature effect on GSR; effect of blood supply on electrodermal measures; reflectance plethysmography Submitted on July 22, 1963
In vitro respiration of normal and pathologic human lung
Authors: Strauss Bella 
Published: December 2017

The Qo2 of normal and pathologic human pulmonary tissue was measured according to the direct method of Warburg. Lung specimens were reduced to rods of intact cells in their normal architectural relationships by the McIlwain chopper. This instrument is thought to eliminate the problem of erratic and incomplete diffusion of oxygen into the preparation by virtue of the fact that tissue can be subdivided into uniformly thin units, well within maximum allowable dimensions as determined by Warburg. Quantitation solely of actively respiring elements by the point-counting method of Chalkley permitted comparison of respiratory rate of normal with abnormal pulmonary tissue and eliminated the problem in calculation of Qo2 of dilution of pathologic material with normal cells and necrotic, nonrespiring elements. Oxygen consumption values for normal, tuberculous, and malignant lung were, respectively, 2.1, 5.4, and 8.6 μl O2/mg dry wt. per hr, suggesting that the oxidative metabolism in tuberculous inflammation and malignancy primary in the lung is elevated significantly. Possible sources of this augmented metabolic rate are discussed. lung tissue metabolism; human pulmonary tissue respiration; tuberculous lung tissue metabolism; lung carcinoma tissue metabolism; lung tissue preparation Submitted on September 19, 1963
Chronic intravenous cannulas for rats
Authors: Weeks James R. , Davis John D. 
Published: December 2017

The intravascular portion was made of silicone rubber, passed down the external jugular vein into the right heart. The remainder was made of polyethylene, brought subcutaneously to the back of the neck. Most cannulas remained functional for many weeks. silicone rubber cannulas Submitted on October 3, 1963
Measurement of intraluminal pressure from external pressure with strain transducers
Authors: Okino Haruka 
Published: December 2017

In an effort to find a means of recording absolute systemic arterial pressure from the skin surface, steady pressures in rubber-walled models were recorded with external pressure-sensing devices. The recorded pressure at which a plateau appeared was dependent on the degree of stretch in the wall of the pressure source. Distortion of the wall of the source by the pressure sensor resulted in a recorded curve with no plateau. The area of the sensor was critical; those with diameters greater than that of the source recorded only part of the internal pressure. When the diameter of the sensor was less than that of the source, a fairly linear relationship between recorded and source pressure could be obtained, but interposition of sponge rubber to simulate tissues lying between the artery and the body surface produced nonlinear responses. It was concluded that external sensors are adequate to record the waveforms of arterial pressure but cannot be reliably calibrated to provide accurate measurement of its level. sensing device, arterial pressure; systemic pressure; measurement, external; internal pressures, measurement of; transcutaneous arterial pressures; arterial pressure sensing; external measurement of systemic pressures Submitted on July 8, 1963
Body fluids and electrolytes after prolonged cardiopulmonary bypass
Authors: Brinsfield Dorothy , Hopf M. A. , Mayer S. E. , Galletti P. M. 
Published: December 2017

Fluid and electrolyte balance was studied in 21 dogs after partial heart-lung bypass of 10 hr duration. Water retention was demonstrated by an increase in body weight and total body water, primarily due to an increase in extracellular fluid. Electrolyte retention was suggested by an increase in total extracellular sodium, potassium, and chloride. Urinary output was relatively normal but a progressive drop in urinary specific gravity was observed during bypass. Blood pH remained essentially unchanged. However, an increase in plasma lactate and a decrease in plasma bicarbonate suggested some degree of hypoxia and metabolic acidosis at the cellular level. Altered hormonal regulation of sodium and water excretion, hemolysis secondary to blood trauma, and the exchange of intracellular potassium for extracellular hydrogen ions were considered possible explanation for the fluid and electrolyte changes observed. assisted circulation; heart-lung bypass; acid-base balance; fluid balance; extracorporeal circulation; electrolyte changes with partial bypass; membrane oxygenator; disc oxygenator; bubble oxygenator Submitted on June 20, 1963
Effects of chlorothiazide on working capacity of normal subjects
Authors: Danzinger Rudolph G. , Cumming Gordon R. 
Published: December 2017

In normal subjects chlorothiazide produced a 21% fall in plasma volume, a 15% decrease in physical working capacity, and an 11% decrease in maximum oxygen consumption. These changes were reversed by intravenous dextran. However, high intensity exercise was carried out despite the decrease in plasma volume. plasma volume; maximum oxygen consumption Submitted on October 18, 1963
Partitioning of respiratory flow resistance in man
Authors: Ferris B. G. , Mead J. , Opie L. H. 
Published: December 2017

Measurements of flow resistance of various components of the respiratory system were measured in adult male subjects in the sitting position. Nasal resistance is the largest single component being nearly one-half the total and two-thirds of the airway resistance during nose breathing. It is highly nonlinear, and shows much variability. During mouth breathing upper airway resistance (mouth, pharynx, glottis, larynx and upper trachea) is also markedly nonlinear, and accounts for one-third the total airway resistance. Lower airway resistance is approximately linear up to flows of 2 liters/sec. Pulmonary tissue resistance is low as reported in this study. Chest wall resistance is nearly linear up to flow rates of 2 liters/sec and accounts for slightly less than half the total respiratory resistance during mouth breathing and 10–19% during nasal breathing. larynx; airways; chest wall; nose Submitted on December 16, 1963
Reproducibility of transient response to CO2 inhalation in man
Authors: Read D. J. C. , Maloney J. E. , Fowler K. T. 
Published: December 2017

The transient changes in ventilation and alveolar PCO2 following the inhalation of 4% CO2 and the return to air have been studied in five normal subjects in an attempt to characterize the intact respiratory chemostat in man. In all 13 studies the changes of ventilation lagged behind those of alveolar PCO2, while the latter consistently over- or undershot its later steady-state value. The timing and magnitude of the responses were in general agreement with the predictions made by Grodins et al., who assumed in their model that the chemoreceptors respond to a single stimulus (PCO2) and are embedded in tissue in equilibrium with venous blood. In four duplicate experiments on individual subjects the quantitative reproducibility of the transients was poor, due largely to cyclic and random variations of ventilation shown by all subjects, even when in the steady state. This precluded any accurate search for differences introduced into the predicted transient response by the adoption of Defares' more sophisticated model, in which the influence of a changing cerebral blood flow on receptor PCO2 is considered. Studies performed during mild hypoxia revealed no change in transient response. control of ventilation; steady-state ventilation; random changes in ventilation; cyclic changes in ventilation; effect of hypoxia on ventilation; respiratory chemoreceptor Submitted on June 24, 1963
Alveolar capillary temperature compared with aortic and bronchial wedge temperatures
Authors: Edwards A. W. T. 
Published: December 2017

Temperature for gas exchange in the alveolar capillaries was determined by the helium-argon method in nine dogs over a range of body temperatures from 37–42 C. The experiments were much more prolonged than those previously carried out in man. Results were compared with simultaneous measurements in the aortic arch, right ventricle, gastrointestinal tract, and bronchial tree. There was no significant difference between alveolar capillary temperatures and those in the right and left heart and bronchial wedge position, even when body temperature was changing. Deep rectal temperatures gave a reasonable estimate of alveolar temperature provided the body temperature was steady, but esophageal and gastric measurements were not reliable, the reading increasing as the stomach was approached. The results support the validity of the helium-argon method and indicate that accurate estimates of alveolar capillary temperature may be obtained by direct measurements in the central circulation or bronchial wedge position. Note: With the Technical Assistance of Judith Laurie alveolar gas exchange; intravascular temperatures; inert gases; solubility of gases; esophageal temperature; gastric temperature Submitted on December 16, 1963
Effect of low concentrations of ozone on pulmonary function in man
Authors: Young W. A. , Shaw D. B. , Bates D. V. 
Published: December 2017

Eleven subjects in sixteen experiments breathed 0.6–0.8 ppm of ozone through a mouthpiece for 2-hr periods. Measurements of pulmonary function were made immediately before and after each experiment. The changes were compared with those observed after a control experiment in which air was breathed through the same circuit for a similar period. In this concentration, ozone was found to produce a highly significant reduction in steady-state D1CO of 5.4 ml CO/min mm Hg, a change about four times larger than that of the air control experiments. The vital capacity, FEV0.75 x 40, and maximal midexpiratory flow rate decreased by about 10% after ozone breathing, the change being statistically significant in the first two of these only. Gas distribution, and dynamic and static pulmonary compliance were measured in two subjects and were not affected by ozone. Thickening of the alveolar wall by edema fluid is suggested as the most likely explanation of the fall in D1CO that has been observed. The vital capacity and expiratory flow rates may be limited in part by tracheobronchial irritation that follows inhalation of 0.6 ppm of ozone for 2 hr. diffusing capacity after breathing ozone; lungs, effect of ozone; pulmonary function after breathing ozone Submitted on September 23, 1963
Physiological reactions to cold of Bushmen, Bantu, and Caucasian males
Authors: Wyndham C. H. , Morrison J. F. , Ward J. S. , Bredell G. A. G. , Von Rahden M. J. E. , Holdsworth L. D. , Wenzel H. G. , Munro A. 
Published: December 2017

Two separate studies of the reactions to cold of one sample of 8 and one sample of 15 Kalahari Bushmen were made in their natural habitat and the results compared with the Bantu and, to a smaller extent, with the Caucasians. With a decrease in temperature from 27 to 5 C the metabolisms of all three groups rose. Metabolic rates per square meter of Bantu and Bushmen were similar, although higher than those of the Caucasians, but the percentage increases were closely similar for all groups. Rectal temperatures of Bushmen and Bantu were similar and decreased as the temperature dropped, while that of the Caucasians rose. Toe and finger temperatures of the Bushmen were higher over the whole temperature range than those of the Bantu and Caucasians, while the average skin temperatures were closely similar. Metabolic rates and rectal temperatures, therefore, indicate that subcutaneous tissue insulation against heat flow is greater for the Caucasians than for the Bantu or the Bushmen. Measurements of average skinfold thicknesses confirm this finding. Bushmen and Bantu reactions are quantitatively similar, but are qualitatively slightly different. From these findings we conclude that the difference between Bushmen, Bantu, and Caucasians is essentially morphological. desert and "river" Bushmen in the heat; effect of morphology on reaction to heat; heat reactions of Bantu and Bushmen; state of acclimatization to heat of Bushmen and Bantu; sweat rates of Bantu and Bushmen in standard heat conditions Submitted on October 21, 1963
Physiological reactions to cold of Caucasian females
Authors: Wyndham C. H. , Morrison J. F. , Williams C. G. , Bredell G. A. G. , Peter J. , Von Rahden M. J. E. , Holdsworth L. D. , Van Graan C. H. , Van Rensburg A. J. , Munro A. 
Published: December 2017

The physiological reactions to cold of nine female Caucasians were examined and compared with the reactions of a sample of male Caucasians. The experiment was conducted in the climatic chamber of the Applied Physiology Laboratory at air temperatures of 27 and 5 C, with a wind velocity of 80–100 ft/min. The sample of nine did not provide for intermediate temperature studies. The metabolic rates of the females were lower than those of the males, at both 27 and 5 C, but when expressed per square meter no differences were found. Finger and toe and rectal temperatures were the same for both sexes at 5 C, but the average female finger temperature was lower than that of the males at 27 C. The average female skin temperature was 2 C lower than that of the males. This indicates a greater subcutaneous insulation for females and this is confirmed by skinifold measurements. Both Caucasian sexes therefore display an increase in rectal temperature with fall in air temperature, which contrasts markedly with the Bantu and Bushman, both of whom show a decrease in rectal temperatures. Caucasian females and cold; cold responses of Caucasian females Submitted on September 17, 1963
Hyperbaric oxygen and persistence of vision in retinal ischemia
Authors: Carlisle R. , Lanphier E. H. , Rahn H. 
Published: December 2017

When retinal ischemia is produced by elevating the intraocular tension, normal vision persists for about 4 sec in healthy subjects breathing air at atmospheric pressure. Persistence times were determined at alveolar oxygen pressures up to 4 atm abs (3,000 mm Hg), obtained by oxygen breathing in a high-pressure chamber. Below an alveolar Po2 of 2 atm the rise in persistence time is relatively small. Above that level the time increases in direct proportion to the increase in alveolar Po2 and may exceed 50 sec at 4 atm. The rise of persistence time follows a pattern similar to that of computed blood oxygen pressure assuming an oxygen extraction of about 3 vol%. high pressure; blood oxygen tension; tissue oxygenation; intraocular tension; retinal circulation; visual blackout Submitted on February 7, 1964