bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative compliances of well and poorly ventilated spaces in the normal human lung
Authors: Fowler K. T. 
Published: December 2017

A series of experiments was performed in each of which the subject inspired a .25-liter bolus of argon in a large breath consisting otherwise of air. The slope of the argon plateau in the subsequent expiration was found to depend upon the lung volume at which the bolus was administered. When inspiring from residual volume to total lung capacity, bolus injection at a low lung volume led to a rising plateau; injection at medium volume led to a flat plateau; and at a high lung volume to a steeply falling plateau. From measurements of the different plateau slopes produced it was possible to deduce the ratio of the effective compliances shown at any lung volume by the “well” and “poorly” ventilated alveolar populations. In four normal subjects this ratio rose from about 0.5 at residual volume to about 4 near total lung capacity. The qualitative behavior of the two populations resembled that of the upper and lower zones of the erect lung, as indicated by the nature of the cardiac oscillations on the expired gas plateaus. lung compliance, range of variation; lung compliance, variation with lung volume Submitted on January 20, 1964
Cardiovascular responses to ice-cold showers
Authors: Keatinge William R. , McIlroy Malcolm B. , Goldfien Alan 
Published: December 2017

A shower of ice-cold water (0@#X2013;2.5 C) over the chest caused large increases in systolic and diastolic arterial pressures, pulse pressure, and pulse rate in normal subjects. Cardiac output rose by 59 and 100% in the two subjects in whom it was measured. The changes in pressure were considerably larger than those caused by a cold pressor test or by anxiety. The changes appear to be due to sympathetic nervous reflexes to the heart and blood vessels rather than release of adrenal catecholamines, as plasma epinephrine did not increase and plasma norepinephrine rose only by 0.32 @#X00B5;g/liter. Hyperventilation and evidence of peripheral venoconstriction occurred during the showers, but neither voluntary hyperventilation nor increased venous return from a change in posture produced the changes in blood pressure seen during shower arterial blood pressure; cardiac output; catecholamines; sympathetic nervous reflexes; hyperventilation; peripheral venoconstriction Submitted on March 10, 1964
Analysis of a micromethod for transmission oximetry of whole blood
Authors: Loewinger Ezra , Gordon Amirav , Weinreb Arye , Gross Jack 
Published: December 2017

The relative roles of absorption and scattering in transmission oximetry of whole blood were examined theoretically and by experiment. It was found that OD 8050 of whole blood is a parabolic function of the hematocrit. The optical density is considerably greater than that of a true solution of hemoglobin except when the hematocrit approaches unity. The optical density is not a linear function of cuvette thickness, again except for hematocrits approaching unity. These experimental results fit the theoretical analysis. Consequently it was possible to design a micromethod for transmission oximetry of whole blood using packed cells in microhematocrit tubes. The correspondence of the modified spectrophotometric method and the gasometric method was sufficiently good to warrant its routine use. oximetry of packed red cells Submitted on June 25, 1963
Effect of negative work on the amount of positive work performed by an isolated muscle
Authors: Cavagna G. A. , Saibene F. P. , Margaria R. 
Published: December 2017

An isolated frog gastrocnemius tetanically stimulated performs a greater amount of positive work, during shortening at a given speed, if it has been stretched immediately before it was allowed to shorten. The increase of work performed is greater, the shorter the interval between stretching and shortening. A substantial amount of the work done on the contracted muscle during the stretching appears to be available during the shortening phase, as in elastic bodies. Note: (With the Technical Assistance of G. Orlando) tension-length diagram of isolated contracted muscle; elasticity of contracted muscle; efficiency of muscular contraction Submitted on May 4, 1964
Effects of salicylate on acclimatization to work in the heat
Authors: Bass David E. , Jacobson Eugene D. 
Published: December 2017

Some effects of daily large doses of sodium salicylate were studied on the pattern of acclimatization to work in the heat. Acclimatization was induced by daily walks of 100 min on a level treadmill at 3.5 mph at 120/80 F (dry bulb/wet bulb). Two matched groups of six men each were acclimatized in this manner and one group received 5.9–7.8 g of sodium salicylate daily over a period of 10 days. Men treated with salicylate exhibited the same qualitative responses as the control group in terms of the acclimatization process, i.e., their rectal temperatures, skin temperatures, and pulse rates during work in the heat were lower on the later days. Quantitatively, the degree of acclimatization (as measured by rectal temperature) was less in the men receiving salicylate than in the control group. This difference was more apparent than real, however, in that when the salicylate group were taken off the drug regimen, they exhibited the same degree of acclimatization in terms of rectal temperature as did the control group. The acclimatization process did not abolish the acute response to salicylate. body temperature regulation; exercise; simulated desert environment; simulated jungle environment; hyperthermia; rectal temperature, skin temperature, sweat rate, and pulse rate in hot environments; antipyretics Submitted on June 15, 1964
Lung diffusing capacity: cyclically and continuously ventilated closed systems
Authors: S⊘lvsteen P. 
Published: December 2017

In previous communications, distribution of ventilation and lung diffusing capacity (Dl) were calculated from changes occurring in N2 and CO concentrations when a subject, whose lungs contained atmospheric air at the beginning of the experiment, respired in a spirometer containing oxygen and a little CO. In the calculations, the system was assumed to be continuously ventilated and without dead space. The present study examines which errors may arise from these simplifications. Equations for cyclic ventilation are derived. Definite values for dead space and for volumes, alveolar ventilation, and Dl of two nonuniformly ventilated lung regions are assumed. Thereupon it is computed how the concentrations of N2 and CO will change, if a subject with the assumed values respires in a spirometer of a given volume. From these changes in concentration, Dl and the distribution of ventilation are calculated using equations for continuous ventilation. The differences between the assumed and the calculated values of Dl are small. mathematics for cyclic ventilation; nonuniform ventilation; calculation of dead space; calculation of lung diffusing capacity Submitted on February 18, 1964
Motor control of pulmonary airways studied by nerve stimulation
Authors: Olsen C. R. , Colebatch H. J. H. , Mebel P. E. , Nadel J. A. , Staub N. C. 
Published: December 2017

To investigate the motor control of the pulmonary airways we combined electrical stimulation of the cervical efferent vagus nerves of cats and dogs with measurement of pulmonary resistance (Rl) and anatomic dead space (Vd), and with anatomic study of rapidly frozen lungs. Stimulus frequencies between 1 and 12/sec produced almost the full range of Rl responses in eight cats. The major constrictor response to stimulation of one vagus nerve was in the lung of the same side in dogs and cats. A decrease of Vd associated with the increase of Rl in five cats during bilateral vagal stimulation suggested that the Rl change resulted from a generalized or large airway narrowing, rather than a local constriction. In seven cats whose lungs were frozen at end inspiration during unilateral vagal stimulation, the lobar bronchi on the stimulated side were smaller in diameter than comparable bronchi of the other side. In only two of seven cats was there definite constriction of the small cartilaginous and membranous airways of the stimulated side by the criterion of longitudinal mucosal ridges; in two there was slight constriction and in the other three, no change. Respiratory bronchioles and alveolar ducts of frozen sections were not constricted. pulmonary resistance; vagus nerve distribution; anatomy of pulmonary airways; vagus nerve impulse frequency; sympathetic nerve inhibition Submitted on May 1, 1964
Heart rate response to held lung volume
Authors: Angelone Alfonso , Coulter Norman A. 
Published: December 2017

It has been shown that respiratory sinus arrhythmia correlates fundamentally with lung volume changes. The correlation with thoracic circumference changes is incidental and quantitatively unreliable. Extensive measurements on one subject and limited measurements on four other subjects demonstrate the existence of a systematic relationship between heart rate and lung volume under reasonably static conditions, a high heart rate corresponding to the expiratory position and a low heart rate to the inspiratory position. This relation has been described successfully with an exponential equation. heart rate and lung volume: exponential relation; heart rate: lung volume dependence; lung volume and thoracic circumference: calibration; respiration and heart rate: static lung volume effect; respiratory sinus arrhythmia: held lung volume and heart rate; sinus arrhythmia: static lung volume dependence; thoracic circumference and lung volume: calibration Submitted on July 22, 1964
Lung volume for initiation of phonation
Authors: Hoshiko Michael S. 
Published: December 2017

The percent of vital capacity at which phonation is normally initiated was investigated. Thirty normal young male and thirty normal young female adults breathed oxygen in a closed circuit respirometer in a standing position. Vital capacity, expiratory reserve, tidal volume for breathing, and phonation volume were determined for each subject. The mean percent of vital capacity at which phonation is normally initiated was found to be 49.7 for males and 50.3 for females. These values approximate end-inspiratory volumes during quiet breathing in the upright posture. breath stream dynamics; communication; respiratory muscle activity; electromyography; respiration Submitted on July 13, 1964
Effect of dimercaprol on oxygen toxicity in rats
Authors: Van Tassel Peter V. 
Published: December 2017

Six groups of 10 male Holtzman rats were given doses of 10, 25, 40, 50, 75, and 100 mg/kg dimercaprol, respectively. Both times of onset of the first convulsion and survival times of treated animals exposed to 6 atm of oxygen were measured and compared with 50 untreated controls. As the dose of dimercaprol increased to 40 mg/kg, both the time of onset of convulsions and the survival time increased to a maximum, and then decreased with further increase in dosage until they reached control levels at a dose of 100 mg/kg. Other animals were given equivalent doses of the vehicle in which the dimercaprol was dissolved, while still others received an inactive analogue of dimercaprol (glycerol). Neither the vehicle nor the inactive analogue produced the protective effect seen with dimercaprol. British antilewisite; hyperbaric oxygen Submitted on August 7, 1964
A rate signal interpreter
Authors: Partridge Lloyd D. , Jones Richard F. 
Published: December 2017

A simple, on-the-line device is described for converting an electrical pulse pattern into a continuous voltage output proportional to the instantaneous pulse rate. The special purpose circuit and an analog computer version are both given. Pulse rates varying by 30:1 are adequately measured. Multiple ranges are provided. A special feature is that a falling rate is followed as soon as the current interval exceeds the last completed interval. The circuit is stable and components are not critical. impulse rate; rate measurement; instrumentation; interval measurement Submitted on November 16, 1964
Voluntary dehydration in man
Authors: Greenleaf John E. , Sargent Frederick 
Published: December 2017

The effects singly and in combination of heat, exercise, and hypohydration upon voluntary dehydration were studied in four acclimated, physically fit, young men. Voluntary dehydration is the delay in complete rehydration following water loss. Hypohydration refers to the state of decreased water content while the osmotic concentration of the body is maintained. Ad libitum drinking during the heat experiments was 146% greater than it was in the cool experiments. Hypohydration increased drinking 109% over the corresponding hydration experiment, exercise increased water intake 41% over resting. Hypohydration and exercise were less effective than heat in stimulating drinking. During the 4-hr experimental periods, the subjects did not or could not drink enough to compensate for the water lost. Regardless of the magnitude of the water deficit at the beginning of the recovery periods, the rates of rehydration were the same. The more stressful the experiment, the greater the water consumption and, in general, the longer it took to regain the lost water. water balance; heat; exercise; drinking; hypohydration Submitted on September 8, 1964
A small electrolytically driven infusion pump
Authors: Baumgarten A. , Curtain C. C. 
Published: December 2017

An electrolytically driven infusion pump has been constructed in which the pressure of gas generated by electrolysis is used to propel the infusate at controllable flow rates. The unit has over-all dimensions of 12.5 x 4.0 cm and consists of a chamber containing the electrolyte solution in a polyurethane sponge inserted between platinum electrodes and a chamber containing a mercury battery which serves as the power source. The infusate is contained in 4.5-mm diameter polythene tubing wound about the body of the pump. A small polythene valve inserted between the tubing and an intravenous catheter prevents reflux of blood. The pump has a capacity of up to 25 ml and a flow rate of 0.5—25 ml/hr. It can operate in any position and is designed for use in human subjects and unrestrained animals. portable infusion pump; self-contained infusion pump; nonmechanical pump Submitted on November 9, 1964
Hair density, wind speed, and heat loss in mammals
Authors: Tregear R. T. 
Published: December 2017

The heat loss from excised pelts of rabbits, horses, and pigs has been measured at various wind speeds. The temperature gradient through the fur was also measured. The thermal insulation of fur is highly dependent on the hair density (i.e., number of hairs/ cm2), and on the wind passing over its surface. If there are less than 1,000 hairs/cm2, an 8-mph wind penetrates deep into the fur, but at higher hair densities an 18-mph wind penetrates only a little way into the fur. fur insulation; obstruction of wind by hair Submitted on September 10, 1964
Permanent physiological fistula of the pancreas and other digestive glands
Authors: Pekas Jerome C. 
Published: December 2017

A method and equipment are described for the preparation of a permanent-type fistula of the pancreas of animals which do not have a papilla of Vater, as the pig. It accommodates the continuous return of the secretion to the duodenum, thereby eliminating the dehydration, anorexia, and early death so common with a permanent fistula of the pancreas where the total secretion is lost from the animal. The type fistula used is unique in that a sensitive one-way valve was used to prevent the reverse flow of ingesta into the pancreas during intervals of high peristalic pressures in the duodenum. The same method has been used to a limited extent to prepare fistulae of the bile duct and isolated segments of intestine and stomach, and may be used for other physiological shunt experiments. gastrointestinal; secretions; one-way valve Submitted on January 16, 1964
A hot-wire microanemometer for measurement of air movements inside clothing
Authors: Krishnaswamy N. , Mani K. V. , Ranganathan S. 
Published: December 2017

A hot-wire anemometer has been specially designed and fabricated for the measurement of the wind speed component of the microenvironment inside clothing. A copper-constantan thermocouple has been used for estimation of temperature. The constant-current method is used for measurement of air movement. The sensing element is mounted in a Perspex frame which can be strapped to the human body inside clothing. Speeds in the range 2–280 cm/sec have been measured with the instrument. anemometer; thermocouple; air velocity inside clothing Submitted on September 8, 1964
Method for recording ECG's in unanesthetized guinea pigs
Authors: Richtarik Alfred , Woolsey Thomas A. , Valdivia Enrique 
Published: December 2017

A device for use in recording ECG's from guinea pigs is described. It is constructed of Plexiglas and consists of a base with four electrodes (separated by plastic ridges) on which the animal stands. The animal's activity is restricted by a removable box, the ends and top of which are adjustable to compensate for variations in animal size. The device permits recording of ECG's in rapid succession from quiet, unanesthetized animals in normal standing posture. Results obtained with the method are reported. apparatus for guinea pig ECG; time relations guinea pig ECG; normal ECG, guinea pig; factors affecting quality of ECG recordings from guinea pigs Submitted on October 21, 1964
An electromyographic electrode designed for identification of recording sites
Authors: Hart Benjamin L. , Kitchell Ralph L. 
Published: December 2017

An electromyographic needle electrode was designed so that a marking substance could be injected through the electrode into the recording site. This made it possible to identify the recording site, in the muscle, at the termination of the experiment when a postmortem examination was performed. Colored petrolatum or mineral oil was used as a biologically inert marking substance. Some of the recording sites were readily located as long as 130 days after injection. perineal muscles; electrode location Submitted on October 22, 1964
A student laboratory exercise illustrating active transport across the small intestine
Authors: Wilson T. Hastings , DeCarlo Angela 
Published: December 2017

A 7-year experience with student laboratory exercises dealing with intestinal transport in vitro is described. A single experiment which has evolved from trial and error in the student laboratory is given in detail. Everted sacs of small intestine from the golden hamster are incubated in flasks containing bicarbonate-saline with 10 mm glucose and 2 mm d- or l-tyrosine. Glucose and l-tyrosine are transported across the intestinal wall against concentration gradients; d-tyrosine is not, illustrating the stereospecificity of the amino acid transport system. A second experiment which illustrates the stimulation of vitamin B12 absorption by gastric intrinsic factor is briefly recorded. The student interest aroused and the high degree of satisfactory results make such experiments useful additions to the repertoire of student laboratory exercises in physiology. intestinal transport; amino acid transport; B12 transport Submitted on November 12, 1964
Respiratory oxygen debt and excess lactate in man
Authors: Thomas H. Duke , Gaos Carlos , Vaughan C. Wayne 
Published: December 2017

The relationship between the respiratory oxygen debt and excess lactate, change in lactate, and change in lactate/pyruvate ratio was examined in 48 experiments in 13 patients and in 13 normal volunteers. The subjects exercised for either 4- or 10-min periods. The recovery period varied from 17 to 45 min. Methods of analysis of lactate and pyruvate were colorimetric in 18 experiments, enzymatic in 20 experiments, and both in 10 experiments. The correlation coefficients between respiratory oxygen debt and excess lactate, delta lactate, and change in lactate/pyruvate ratio were 0.83, 0.87, and 0.85, respectively, in the colorimetric determinations. The enzymatic group showed somewhat poorer coefficients of correlation for these same variables: 0.76, 0.77, and 0.83, respectively. However, none of these relationships were one-to-one, and the correlation coefficients were poor for all of these variables in both series when they were subdivided into two groups based on whether the respiratory oxygen debt was greater or less than 2.2 liters/m2. excess lactate oxygen equivalents; change in lactate pyruvate; lactate/pyruvate ratio Submitted on June 15, 1964
Changes in the aerobic capacity and body composition in obese boys after reduction
Authors: Šprynarová ŠtĚpánka , Pařízková Jana 
Published: December 2017

Seven obese boys submitted themselves to a 7-week regimen of dietary restriction and regular exercise. Measurements were made at the beginning and end of the period. A significant drop in body weight was achieved by reduction of adipose tissue and also of lean body mass (LBM). The ratio of LBM to body weight increased. These changes were associated with significant drop of maximum oxygen consumption. The increase of the Vo2 max per kilogram of body weight and the drop of the Vo2 max per kilogram of LBM were not significant. Between the decrease of LBM and the drop of Vo2 max there exists a significant negative relationship; and between the decrease of LBM and the rise of the Vo2 max per kilogram of body weight, a significant positive relationship. The decrease of Vo2 max in these boys was not considered due to deteriorated circulatory or respiratory function but to changes in body composition. maximum O2 consumption; body weight reduction; lean body mass Submitted on February 17, 1964
A search for a pulsatile component in pulmonary capillary blood volume
Authors: Fowler K. T. , Maloney J. E. 
Published: December 2017

An examination was made of externally detected radioactivity over the thorax of two human subjects after the infusion of red cells labeled with Cr51. An electronic gating technique was used which enabled the mean counting rate to be determined over various preselected time intervals within the cardiac cycle and a comparison made between the rates which obtained during each quarter of this. When counting over the heart the rates were 20—30% greater in diastole than in systole. When counting over rib 2 or rib 4 on the right side no significant variation in count rate could be detected. From this it was deduced that pulmonary parenchymal blood volume in these regions did not vary by more than ± 10% within the cardiac cycle. It was concluded that within the erect lung a proportion of closed capillaries exists in the upper zone, and that the distensibility of the small vessels is insufficient to explain the large vertical inequality of blood flow observed experimentally. pulmonary circulation; parenchymal blood volume; pulsations in volume; distensibility of small vessels Submitted on August 17, 1964
Relationship between chest wall and pulmonary compliance and age
Authors: Mittman Charles , Edelman Norman H. , Norris Arthur H. , Shock Nathan W. 
Published: December 2017

Chest wall and pulmonary compliance were measured in 42 normal males aged 24—78 years. Measurements were made using the static method and the positive-pressure breathing method of Heaf and Prime. Chest wall compliance decreased significantly with age. Pulmonary compliance measured at functional residual capacity was similar in old and young subjects. As lung volume increased pulmonary compliance decreased more in the young than in the old. The latter age difference may result from a loss of lung elastic recoil in the elderly or may be due totally to the age difference in chest wall compliance. The observed age differences in lung compartment volumes can largely be accounted for by the decrease in chest wall compliance. aging; chest wall compliance; lung compliance; static measurement of compliance; positive-pressure measurement of compliance; lung volumes; residual volume Submitted on July 17, 1964