bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of gas chromatography to respiratory gas analysis
Authors: Hamilton Lyle H. , Kory Ross C. 
Published: December 2017

Analyses of respiratory gases for CO2 and O2 can be performed on a single sample with the Fisher model 25 gas partitioner. By modifying the instrument and adding a Wilkens gas-sampling valve and a zero-suppression selector to the system, we have been able to achieve analytical accuracy comparable to that for the Scholander micrometer gas analyzer. The zero-suppression selector was considered to be essential for achieving maximum accuracy with peak height measurements. With this system, the standard deviation for its accuracy was ±0.024 vol. % for o2 and approximately ±0.002 vol. % for CO2 in respiratory gas samples. Empirical equations were developed to correct for argon interference in O2 determinations. Gas chromatography offers a unique advantage which is not shared by other instruments. It provides a single analytical technique for the simple and accurate analysis of a wide spectrum of gases useful in studies of respiratory physiology and pathology. Submitted on April 4, 1960
A re-evaluation of effects of acute central congestion on pulmonary compliance in normal subjects
Authors: Bondurant Stuart , Mead Jere , Cook C. D. 
Published: December 2017

In a re-examination of the effects on lung compliance of acute central vascular engorgement produced in normal subjects by inflation of a ‘G suit’ it was found that the reduction in complicance, previously reported, during suit inflation was in part due to artifactual changes in esophageal pressure. When the esophageal balloon used for pressure recording was positioned higher on the esophagus than in the previous study, and when decreases in mid-position, which usually accompany the abdominal compression associated with suit inflation, were prevented, the complicance reductions in a small group of subjects were approximately one-half as great as those obtained with the balloon low in the esophagus and with the mid-position uncontrolled. Extrinsic pressures from distended mediastinal structures, greater in the distal esophagus, and greater at low lung volumes are thought to be responsible. Additional observations are presented which support this possibility. It is concluded that respiratory esophageal pressure change may not be a valid index of lung surface pressure change in the presence of central vascular congestion. Those measurements of pulmonary compliance during clinical and experimental central vascular engorgement which have used esophageal pressure must be accepted with this reservation. Submitted on March 18, 1960
Gastric osmolar clearance and ionic barter: two mechanisms of electrolyte secretion by the human stomach
Authors: Hirschowitz Basil I. 
Published: December 2017

Measurements of gastric juice volume (V) and H ion (H), chloride ion (ClG), Na ion (NaG) concentrations and of osmolality (OG) as well as plasma sodium (NaP) and osmolality (OP) were made in nine men before and after a subcutaneous injection of histamine. The gastric osmolar clearance (GOC) was calculated from the formula (V·OG)/OP and this correlated well with both acid and chloride output. The theoretical clearance of sodium (TCNa) was calculated for each specimen by the formula (V·OG·NaP)/OP, and this equaled the output of acid plus sodium in the gastric juice V(H + NaG). The mol-mol relationship furthermore suggests that the gastric acid is secreted on a 1:1 basis in exchange for Na ions theoretically cleared within the framework of a gastric osmolar clearance mechanism. It also explains why, even under the most optimal conditions in man, the maximum value for H+ concentration does not exceed 150 mEq/l. On the basis of these observations it is suggested that the various theories which propose a primary acid secretion of 167, 169, 208 or 464 mn, respectively, are unlikely. Submitted on January 22, 1960
Fraction of maximum breathing capacity available for prolonged hyperventilation
Authors: Zocche Gian Paolo , Fritts Harry W. , Cournand Andre 
Published: December 2017

The volume of ventilation which nine healthy young men could maintain for 15 minutes was only 53% of the maximum breathing capacity (MBC). A similar figure was obtained for older patients with chronic pulmonary emphysema. These data suggest that the MBC is not the limiting response to be expected from stimuli such as hypoxia or hypercapnia, and that the capacity of a patient for maintaining an augmented minute volume is an important determinant of the responses these stimuli evoke. Submitted on May 27, 1960
Ventilation of lungs in infant and adult rats and its responses to hypoxia
Authors: Adolph E. F. , Hoy P. A. 
Published: December 2017

Do the controls of breathing differ with age? Pulmonary ventilation was measured by body plethysmograph and pressure transducer. After birth, breathing was irregular (pneumotaxic); steadiness from breath to breath was gained at 3 days; extraction of oxygen from the inspired air became more uniform after 10 days. In pO2 20–40 mm Hg only infants survived a half hour; ventilation did not usually increase, and often decreased. Hyperventilation even in 40 mm Hg was not sustained for many minutes in the newborn, but by 6 days was large and enduring. Heartbeats decreased in frequency during severe hypoxia. Oxygen consumption decreased 75% during hypoxia that allowed survival of infants; it sometimes recovered only slowly after hypoxia ended. Tolerance of infants to low oxygen thus consisted in ability to utilize some oxygen at low pressures and to dispense with some oxygen. Some factor other than pCO2 or pO2, possibly centrogenic, often controlled ventilation in infancy. Low oxygen maximally accelerated the breathing at an age when endurance of hypoxia remained. Submitted on May 12, 1960
Transient effect of sudden mild hypoxia on respiration
Authors: Hornbein Thomas F. , Roos Albert , Griffo Zora J. 
Published: December 2017

Recent studies of carotid body chemoreceptor activity in cats show that the activity of these organs increases markedly over a range of alveolar pO2 considerably higher than the alveolar pO2 of 50–60 mm Hg known to produce an increase in ventilation in the steady state. In an attempt to explain this discrepancy between chemoreceptor activity and ventilation, the transient ventilatory response to two breaths of a low O2 mixture was observed and correlated with the alveolar pO2 during this brief hypoxic stimulus. A transient increase in ventilation could be detected at an alveolar pO2 of 93 mm Hg, that is, considerably higher than the highest pO2 known to increase ventilation during the steady state. These findings are interpreted as evidence of an increased chemoreceptor drive when alveolar O2 tension is lowered only slightly below that existing at sea level. Possible reasons for the difference between the steady state and transient responses are discussed. Submitted on June 6, 1960
Some factors modifying the expression of human strength
Authors: Ikai Michio , Steinhaus Arthur H 
Published: December 2017

The maximal pull of forearm flexors was increased and, in some instances, decreased in predictable fashion by a loud noise, by the subject's own outcry, by certain pharmacologic agents (alcohol, adrenaline, and amphetamine), and by hypnosis. Significant average changes ranging from +26.5% to –31% were observed. An analysis of these data and that of others leads us to regard all performances short of the maximum limit, which is always imposed by the structure and prevailing physiologic state of the performing muscles, to be manifestations of acquired inhibitions that in turn are subject to disinhibition by pure Pavlovian procedures, by anesthetization of inhibitory mechanisms, or by pharmacologically induced symptoms serving as stimuli for disinhibition. Submitted on June 20, 1960
Effect of training on physical fitness of women students
Authors: Sloan A. W. 
Published: December 2017

To ascertain the effect of physical training on young women, four groups were subjected to a modified Harvard step test at the beginning of the academic year and again 4 and 9 months later. One group, specializing in physical education, had a very active program of gymnastics, dancing and games; two other groups had a much less active program; a fourth group had no physical training at all. In the series as a whole there was no correlation between fitness index and either height or weight and no evidence that menstruation influenced performance of the test. At the beginning of the investigation the physical education students had higher fitness indexes than the others and they improved with training. Lesser degrees of physical training caused no significant increase in fitness index but counteracted a tendency to deterioration observed in the group that had no physical training. Changes in the resting pulse were less consistent, and resting pulse rates showed little correlation with fitness indexes. Submitted on June 1, 1960
Unilateral hypoventilation produced in dogs by occluding one pulmonary artery
Authors: Severinghaus John W. , Swenson Edward W. , Finley Theodore N. , Lategola Michael T. , Williams Jack 
Published: December 2017

Temporary unilateral pulmonary artery occlusion resulted within 1 minute in a shift of tidal volume away from unperfused lungs in 14 anesthetized closed-chest dogs. The shift of ventilation was caused by bronchoconstriction following the decrease of CO2 on the occluded side. It was prevented by inhalation into that side of 6% CO2 in air, isoproterenol aerosol or 100% N2, but not by atropine or vagotomy. Airway resistance on the occluded side was doubled, and compliance fell 25%. Functional residual capacity fell variably (0–25%), and anatomic dead space decreased. When blood flow was restored, shunting was detected and ventilation returned slowly with normal inflation or immediately after hyperinflation of that lung. This suggests that terminal and respiratory bronchiolar smooth muscle constriction may lead to airway closure and atelectasis and that the gas exchange of the smooth muscle in smaller airways is carried out by direct diffusion to and from the airway rather than with blood. Submitted on June 9, 1960
Circulatory response to ventilatory obstruction during steady-state exercise
Authors: Levy A. M. , Hanson J. S. , Tabakin B. S. 
Published: December 2017

The effects of expiratory airway obstruction on cardiac output during treadmill exercise were studied in nine normal males. Significant changes occurred in all subjects but were unpredictable with regard to magnitude, direction and time of occurrence. The uniformity of the ventilatory response was in sharp contrast to these circulatory variations. Alterations in central blood volume paralleled changes in cardiac output. Physiological mechanisms involved are discussed. Submitted on August 25, 1960
Extrathoracic airway resistance in man
Authors: Hyatt Robert E. , Wilcox Roger E. 
Published: December 2017

Simultaneous extrathoracic and intrathoracic flow resistance was measured in 19 unanesthetized subjects during mouth breathing. Lateral intratracheal pressure was recorded from a needle introduced 2 cm below the larynx. The intratracheal-oral pressure gradient was recorded during various respiratory maneuvers. The pressure drop from esophagus to trachea was also recorded. The extrathoracic pressure-flow relationships were alinear. Large inter- and intrasubject variability in upper airway resistance was encountered. Some factors contributing to this variability were defined. The upper airway accounted for approximately 45% of the total airway resistance in nine normal and 20% in 10 emphysematous human subjects. Upper airway resistance decreased with increasing lung inflation in four normal subjects. The magnitude and potential variability of the upper airway resistance must be considered in evaluating maneuvers designed to alter intrathoracic flow resistance, especially in normal human beings. It appears that during mouth breathing the major component of the upper airway resistance is located in the larynx. Submitted on September 14, 1960
Pulmonary surface tension and alveolar stability
Authors: Clements John A. , Hustead Robert F. , Johnson Rudolph P. , Gribetz Irwin 
Published: December 2017

Human and rat lungs were degassed and filled with air and physiological salt solution for determination of pressure-volume relationships. Extracts were prepared from the specimens and examined for their surface film-forming activity. Both the aeration of the alveolar structure of the lungs at functional residual pressure and the surface activity of the extracts showed wide variation. Numerical ratios were defined to express these two properties quantitatively, and a high degree of correlation was observed between them. The range of correlation was extended by treating the rat lungs with nonionic detergents. These findings support the hypothesis that the stability of the pulmonary alveolar structure is dependent on intrinsic surface-active material and have encouraged further attempts at formulating a theory of alveolar mechanics, taking surface forces into account. The theory is presented, and some of its weaknesses are pointed out. Submitted on October 21, 1960
Gas exchange after autologous pulmonary embolism in dogs
Authors: Stein Myron , Forkner Claude E. , Robin Eugene D. , Wessler Stanford 
Published: December 2017

The ventilatory and arterial blood gas responses to serum-induced thrombi embolized to the pulmonary circulation of the dog have been measured. An increase in rate and minute volume of ventilation independent of the extent of the pulmonary artery obstruction were almost invariably observed. The release of thrombi to the lungs was associated with an arterial-alveolar CO2 tension difference that was dependent on the extent of arterial obstruction. Significant decreases in arterial O2 saturation occurred in animals with massive embolization in the presence of a total minute and alveolar ventilation significantly greater than control values. Failure of arterial O2 concentration to rise to control levels after inhalation of 99.6% O2 indicated that emboli of the dogs' own blood produced a perfusion defect consistent with a right to left shunt. Submitted on November 21, 1960
Pressure-volume relations of lung and thoracic cage in pulmonary emphysema
Authors: Ting Er Yi , Lyons Harold A. 
Published: December 2017

In ten emphysematous and six normal subjects, the pressure-volume curve of the thoracic cage was obtained by arithmetic subtraction, since Pt (total pressure) = Pl (lung pressure) + Pc (thoracic cage pressure). A low compliance of the thoracic cage was found for five emphysematous patients whose total lung capacities (TLC) averaged 93 % of predicted values. In the remaining five patients whose TLC averaged 123% of predicted normal, the compliance values for all the components were nearly normal. In all ten of the patients a normal compliance for lung was found. The respective values of compliance, in liters per centimeter H2O, for the patients with normal TLC were: total respiratory system, 0.039; lung, 0.132; and thoracic cage, 0.056; and for the patients with the larger TLC, were: total respiratory system, 0.075; lung, 0.141; and thoracic cage, 0.154 The major difference was the compliance of the thoracic wall which contributed to the reduction of the compliance of the total respiratory system. The data indicate that some emphysematous patients have a low compliance of the thoracic cage which contributes to the over-all increase in the elastic resistance of the total respiratory system. Submitted on June 10, 1959
Measurement of cardiac output and "central" blood volume by various systems
Authors: Marshall Robert J. , Allwood Michael J. , Keck Ernst W. O. , Shepherd John T. 
Published: December 2017

Dilution curves were obtained by sampling from the aortic root or a carotid artery after injection of indicator dye into the pulmonary artery in five dogs at rest and during exercise. On four occasions a common sampling system was used; curves were recorded simultaneously and in parallel from a cuvette oximeter assembly with a slow dynamic response and from a phototube densitometer with a fast response. In the fifth study, separate slow and fast sampling systems were used interchangeably with the two detecting instruments. Values for cardiac output were similar with the two instruments; maximal divergence for any single observation was 9% from the line of identity. The aortic root is a favorable sampling site for such a comparison, since extrapolation of the dilution curves is usually unnecessary. Under these conditions measurement of cardiac output was not influenced by the dynamic response characteristics of the sampling-detecting-recording system. When mean transit times of the respective curves were corrected for instrumental delay, there was also satisfactory agreement in values for “central” blood volume. However, since the time correction for the densitometer is relatively small, it is the preferable instrument for this measurement. Submitted on October 24, 1960
Composition and caloric density of weight loss during caloric restriction in cold
Authors: Iampietro P. F. , Goldman R. F. , Mager M. , Bass David E. 
Published: December 2017

Two groups of six men each lived for 14 days in a cold chamber at 60 F (15.6 C); activity was sedentary and only athletic shorts were worn. During this period one group, A, was semi-starved (600 kcal/day) and the other, B, was completely starved (0 kcal/day). Changes in body composition were measured and caloric density of weight loss was calculated. Mean weight loss was 5.66 kg for A, and 8.56 kg for B. Composition and caloric density of weight loss was almost identical for both groups. Composition of weight loss with regard to fat, protein and water was 39, 10, and 51% for A; 39, 11, and 49% for B. Caloric density was 3.91 kcal/g for A and 4.06 kcal/g for B. Submitted on February 20, 1961
Pulmonary hemodynamics during positive-pressure breathing
Authors: Linde Leonard M. , Simmons Daniel H. , Ellman Edward L. 
Published: December 2017

The effects of positive-pressure breathing on pulmonary blood flow in the intact anesthetized dog were measured and compared with pulmonary hemodynamics during spontaneous breathing. Using fluoroscopically placed cardiac catheters, pulmonary arterial and venous pressures were measured. Transmural pressures were determined by subtraction of intrapleural pressures, using a differential transducer. Cardiac outputs were determined by the dye-dilution technique, using cardiogreen. Cardiac output fell significantly with positive-pressure breathing, compared with the value during spontaneous respiration. Pulmonary vascular resistance did not differ with the two types of respiration. Although absolute pulmonary arterial and venous pressures rose, as expected, with pressure breathing, their transmural pressures did not change. These studies indicate that there is no primary change in pulmonary hemodynamics with positive-pressure breathing. Decreased cardiac output results from the decreased venous return which is related to the increased intrathoracic pressure during positive-pressure breathing. Submitted on January 16, 1961
Apparent dye-dilution curves produced by injection of transparent solutions
Authors: Sinclair John D. , Sutterer William F. , Fox Irwin J. , Wood Earl H. 
Published: December 2017

In studies on dogs, blood was sampled as for the recording of dye-dilution curves through monochromatic densitometers. Injection of hypertonic media into the superior vena cava caused transient increases in the optical density of blood in the pulmonary and femoral arteries so as to produce apparent “dye” curves. The injection of hypotonic and hemolyzing media produced negative deflections, representing decreases in the optical density of blood, as did brief ventilation with 5% and 50% carbon dioxide in oxygen. Similar changes were demonstrated in vitro. They were compensated for in vivo by the use of a dichromatic densitometer. The changes observed are attributed to altered physical properties of the erythrocytes, which consequently change their light-transmitting and light-reflecting characteristics. Such nonspecific changes in the optical density of blood may constitute an important source of error in monochromatic densitometry done on whole blood. Submitted on January 11, 1961
Influences of hexamethonium and some dietary factors on human pancreatic and bile secretion
Authors: Hong S. S. , Chin D. S. , Hur K. B. 
Published: December 2017

Bile and pancreatic juice were collected from three patients. Each, following sphincterotomy and cholecystectomy, had been subjected to pancreatic and common bile duct intubation. Both milk and 1% dl–methionine by stomach tube increased the volume output of pancreatic juice and bile and also the concentration of amylase, lipase, and cholic acid, respectively. In the case of the pancreas these responses were not seen following hexamethonium but the biliary responses persisted unchanged. A watery decoction of rice increased the volume and enzyme output of the pancreas but did not affect the bile. Bile cholate and volume were increased by 20% glucose solution, water, and beer (5% alcohol). Pancreatic secretion (enzymes and volume) was inhibited by 20% glucose, unchanged by water and stimulated by beer. Submitted on February 13, 1961
Oxygen in tissues during deep hypothermia
Authors: Byon Y. K. , Adolph E. F. 
Published: December 2017

An oxygen electrode and a thermistor were placed in the brain stem, leg muscle, or abdomen of a rat cooled to 17—15 C. When the rat was thereafter kept at 16∘the electrode usually showed a steady current. At 13—11∘ the apparent Po2 of tissue in most instances diminished during 2—3 hr unless artificial breathing was given. Forced breathing of air or oxygen ordinarily raised the Po2; of nitrogen usually, but not always, lowered the Po2. When the apparent Po2 was not thus raised or lowered, the flow of blood to the one tissue being examined, but not necessarily to all tissues, was evidently inadequate. The heart could be stopped reversibly by further cooling to 9—5∘; brain Po2 diminished only gradually at that low temperature. Survival was assured by a Po2 that was high and steady, but often occurred also after a diminishing or zero Po2. In the hypothermic rat, either pulmonary ventilation or systemic blood flow or an unidentified factor could limit the rat's survival. Submitted on October 26, 1960
Chamber cold acclimatization in man
Authors: Davis Thomas R. A. 
Published: December 2017

In March, ten nude subjects were exposed 8 hr daily for 31 days to an air temperature of 11.8 C. In September, another six subjects were similarly acclimatized to an air temperature of 13.5 C. Measurements were made of the responses of shivering, oxygen consumption, rectal temperature, and skin temperature to a standard cold exposure. By the 14th day, shivering in both groups decreased significantly. Heat production remained unchanged in the winter group but decreased in the summer group. Basal metabolism did not change in either group. In both groups, rectal temperatures were maintained at lower values after the exposure period. In the winter group extremity temperatures were unchanged; those in the summer group were lowered by a small amount. The decrease in heat production and mean surface temperature in the summer group is related to the seasonal difference in cold acclimatization. Failure of cold-elevated metabolism to decrease despite a highly significant decrease in shivering indicates the presence of nonshivering thermogenesis in man. It is concluded that man can be artificially cold acclimatized. Note: With the Technical Assistance of D. R. Johnston, F. C. Bell, W. Rawlings, and L. Lee Submitted on May 8, 1961