bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abdominal and thoracic pressures at different lung volumes
Authors: Agostoni Emilio , Rahn Hermann 
Published: December 2017

The abdominal (gastric) pressures as well as the intrathoracic pressures were recorded in man during various respiratory maneuvers such as complete relaxation, moderate inspiratory and expiratory efforts, maximal inspiratory and expiratory efforts, and during maximal abdominal pressure efforts. Each maneuver was systematically carried out at various lung volumes. From these measurements it is possible to determine the transdiaphragmatic pressure difference and thus obtain information concerning the activity of the diaphragm during these various maneuvers. During relaxation pressure maneuvers and during moderate expiratory pressure efforts the transdiaphragmatic pressure difference is zero. During maximal inspiratory efforts the pressure is about 100 cm H2O more positive on the abdominal side than on the thoracic side of the diaphragm regardless of the lung volume. A similar difference is found during a maximal abdominal contraction whether during this maneuver the alveolar pressure is zero or whether a high alveolar expiratory pressure is developed. These findings are discussed in terms of reflex contractions of the diaphragm which limit the pressures and volumes that can be obtained in the lung. Submitted on May 2, 1960
Effect of sleep on CO2 stimulation of breathing in acute and chronic hypoxia
Authors: Reed Donal J. , Kellogg Ralph H. 
Published: December 2017

The effect of sleep on the respiratory response to graded increases in CO2 was studied in four adult male, sea-level residents during hypoxia at sea level, during 23 days at 14,250 ft. and after return to sea level. One subject was also studied at sea level breathing CO2 mixtures with alternating high and low O2. Hypoxia had no apparent effect on the change in respiratory response to CO2 associated with sleep under any of the conditions studied, but it shifted the curve relating respiratory minute volume to alveolar CO2 tension about 1 mm Hg to the left awake and during sleep. It was concluded that sleep and hypoxia act independently rather than interacting in their effect on the respiratory response to CO2. Submitted on June 6, 1960
Effects of exercise on heart output of the dog
Authors: Bailie Michael D. , Robinson Sid , Rostorfer Howard H. , Newton Jerry L. 
Published: December 2017

Effects of varying rates of work on the heart output of healthy young dogs were determined by the direct Fick method. Blood was sampled simultaneously through a polyethylene catheter in the right ventricle and an inlying needle in the left carotid artery. Heart rates were determined from right ventricular pressure recordings. Oxygen consumption was determined by the open-circuit method. Oxygen consumption of the dog was linearly related to work rate in runs on the treadmill at 5.6, 9.6 and 12.9 km/hr. up an 18% grade. Minute volume of the heart, arteriovenous oxygen difference, heart rate and stroke volume were found to increase with increasing metabolic rate. The average stroke volume in the hardest work rate was 82% greater than the average resting value. An animal whose activity had been greatly restricted for 3 months showed a 62% increase in stroke volume from rest to running on the treadmill at 9.6 km/hr. up an 18% grade. The data show that a substantial increase in stroke volume in work must necessarily occur in order to account for the observed increase in minute volume. Submitted on May 10, 1960
Assessment of physical work capacity
Authors: Hettinger Theodor , Birkhead Newton C. , Horvath Steven M. , Issekutz Bela , Rodahl Kaare 
Published: December 2017

Maximal oxygen uptakes were compared with the results from five different tests of physical work capacity in 96 men, 23–62 years of age. In addition, the 'predicted' maximal oxygen uptakes, according to the Ǻstrand-Ryhming nomogram, were compared with the actual measured maximal oxygen uptakes in the 28 subjects who were between 20 and 30 years of age. There was a statistically significant correlation between the maximal oxygen uptake and the following tests: the Harvard step test (P < .001); a new modified step test in which adjustments were made for the body weight and the length of the legs of the subject (P < .001); the Master step test (P < .05); and the Amplituden-Puls-Frequenz test, (P < .02). There was no statistically significant correlation between the maximal oxygen uptake and the Leistungs-Pulsindex. The correlation between the predicted maximal oxygen uptake and the measured maximal oxygen uptake was statistically significant at the .01 level. Submitted on May 16, 1960
Volume-pressure and length-tension measurements in human tracheal and bronchial segments
Authors: Croteau J. Russell , Cook Charles D. 
Published: December 2017

Volume-pressure relations of isolated human tracheal and bronchial segments obtained post mortem from 21 patients, representing a wide age range (newborn premature infants to elderly adults), were studied. With intraluminal pressures above atmospheric, there was a progressive decrease in tracheal and bronchial compliance with increasing age. At +10 cm H2O intraluminal pressure, tracheal segments increased from 46 to 101% in volume, the greatest change being in the younger subjects. At +20 cm H2O pressure, tracheal segments increased from 52 to 129% in volume. The bronchi increased from 30% to 60% with +10 cm H2O pressure. When various weights were applied to the segments, there was a greater relative change in length of segments from younger subjects. Submitted on July 5, 1960
Effect of body posture on lung volumes
Authors: Moreno Francisco , Lyons Harold A. 
Published: December 2017

The changes produced by body posture on total lung capacity and its subdivisions have been reported for all positions except the prone position. Twenty normal subjects, twelve males and eight females, had determinations of total lung capacity in the three body positions, sitting, supine and prone. Tidal volume, minute ventilation and O2 consumption were also measured. The changes found on assumption of the supine position from the sitting position were similar to those previously reported. For the prone position, a smaller inspiratory capacity and a larger expiratory reserve volume were found. The mean values were changed, respectively, –8% and +37%. Associated with these changes was a significant increase of the functional residual capacity by 636 ml. Ventilation did not change significantly from that found during sitting, unlike the findings associated with the supine position, in which position the tidal volume was decreased. Respiratory frequency remained the same for all positions. Submitted on April 5, 1960
Vestibular reactions during prolonged constant angular acceleration
Authors: Guedry F. E. , Lauver L. S. 
Published: December 2017

Six human subjects received stimuli of 2 deg/sec.2 for 45 seconds and 1.5 deg/sec.2 for 60 seconds. Direct-coupled amplification of corneoretinal potential was used to record eye movements. Although some subjects occasionally showed a rise and decline in the velocity of nystagmus during constant angular acceleration, typically, near-maximum velocity was attained in about 30 seconds with little subsequent gain or loss until acceleration ended. Routinely, nystagmus outlasted the subjective afterreaction. Departures from previous results seem attributable to maintenance of alertness by requiring continuous estimation of subjective events. Theoretical implications of the divergence between the subjective and oculomotor aspects of the reaction are discussed. Submitted on August 19, 1960
Relation of changing levels of physical fitness to human cold acclimatization
Authors: Heberling Earl J. , Adams Thomas 
Published: December 2017

Five nude Caucasian men were exposed for 1 hour to a temperature of 10° α 1°C in a cold chamber after normal activity, after physical training, and after bivouac in the interior of Alaska for 6 weeks during January and February. Body temperatures (hand, foot, trunk, skin, and rectal, recorded during exposure to acute cold, were the criteria by which the effects of the changing levels of physical training and the cold-acclimatizing encampment were compared and judged. After the program of physical training, but before the bivouac, skin and extremity temperatures were statistically higher than those recorded before training; no differences were noted after the bivouac, when the level of physical training remained unchanged and the only variable was exposure to cold. These data confirm an earlier suggestion that commonly accepted indices of acclimatization, (elevated skin temperatures) may also result from chronically elevated levels of physical activity. Additional evidence indicates the limitations of the bivouac or field exercises for 'cold exposure,' and suggests the questionable value of accepting physiological and thermal readjustments that occur during such programs as being indicative of the effects of cold. Submitted on July 5, 1960
Loss of potential young in the ewe due to high ambient temperature
Authors: Alliston C. W. , Egli Gene E. , Ulberg L. C. 
Published: December 2017

Embryonic development and other measures of reproductive performance were compared for 3 years in sheep maintained at 65°F, at prevailing summer temperatures, and at a constant, high temperature (92°F). The concentration and motility of the sperm and the fertility of the semen from control rams declined during periods of high temperature. Fertilization rate was lowered when rams were exposed to high prevailing atmospheric temperatures or ewes to a constant high temperature. A higher percentage of morphologically abnormal ova was recovered from ewes subjected to the higher temperatures. The stages of embryonic development indicated that, in ewes at the higher temperature, a loss of potential young occurs by a cessation of development during cleavage. Submitted on May 6, 1960
Cardiac output measured by thermal dilution of room temperature injectate
Authors: Evonuk Eugene , Imig Charles J. , Greenfield Wilbert , Eckstein John W. 
Published: December 2017

A technique is described for recording time concentration curves utilizing the thermal dilution method using normal room-temperature isotonic saline as the dilution indicator. This technique was compared with the dye dilution method by simultaneously recording the left heart output with each of the methods. The coefficient of correlation between these simultaneous measurements was 0.962. Paired analysis showed the thermal measurements to be 4% greater than dye measurements. However, their reproducibilities and sensitivities were comparable. Simultaneous thermal measurements for both sides of the heart resulted in a slightly higher reading (2%) from the left side. In spite of this small difference the reproducibilities with either side were comparable. The coefficient of correlation between the two was 0.96. A formula is advanced for calculating cardiac output from thermal dilution curves. The thermal dilution technique described provides a satisfactory method for estimating either right or left heart outputs. Submitted on August 12, 1960
Validity of internal jugular blood for study of cerebral blood flow and metabolism
Authors: Lassen Niels A. , Lane Mark H. 
Published: December 2017

Internal jugular blood sampled by percutaneous puncture below the mastoid process has been studied extensively in man on the assumption that it represents cerebral venous blood without significant admixture of extracerebral venous blood. A series of 67 internal jugular blood studies revealed 5 markedly deviant observations characterized by a very slow rate of inert gas saturation (i.e. a very slow blood perfusion) and a narrow arteriovenous oxygen difference. Similar findings were obtained in two studies of external jugular blood. These observations and technical details regarding the venous punctures suggest that the five deviant cases were grossly contaminated by extracerebral venous blood, the venous blood coming from some other vein in the neck than the superior bulb of the internal jugular vein. Although such cases are relatively rare, they deviate so markedly from essentially uncontaminated cases that their exclusion adds considerably to the validity of internal jugular blood for the study of cerebral blood flow and metabolism in man. Submitted on March 2, 1960
Mobilization of free fatty acids in dogs during respiratory acidosis
Authors: McElroy William T. , Spitzer John J. 
Published: December 2017

To assay changes in plasma free fatty acids (FFA) during a stress reported to activate a sympathetic discharge, dogs were made hypercapnic by inhaling mixtures of gases containing 15–30% CO2 in O2. Results showed that during such a maneuver, plasma FFA and glucose concentrations were elevated. Blood pH and heart rates were decreased and mean blood pressures fell in the early stage of hypercarbia, but gradually rose back to normal within 30 minutes. Dogs with adrenal glands occluded from the circulation showed little or no change in plasma concentrations of FFA or glucose, although blood pH and heart rates declined quantitatively the same as in intact dogs. 'Adrenalectomized' dogs were unable to reset lowered blood pressures at pre-CO2 levels when breathing 30% CO2. It is concluded that, during the stress of respiratory acidosis, a sympathetic discharge activates a release of adrenal medullary amines, and these in turn raise not only glucose levels, but also FFA, an important energy source. Submitted on August 22, 1960
Thermal and metabolic responses of men in the Antarctic to a standard cold stress
Authors: Milan Frederick A. , Elsner Robert W. , Rodahl Kaare 
Published: December 2017

Thermal and metabolic responses of eight male subjects exposed nude for 2 hr to a standard cold stress (17 α 1.0 C air temperature) were examined in the austral fall, winter, and spring at Little America in the Antarctic. Mean body, average skin and foot temperatures increased significantly after 3 months. Neither rectal nor finger temperatures were changed over the year. Although basal metabolic rates were unchanged, there was a significant decrease in the metabolic responses to the standard cold stress after 3 months in the Antarctic. It is suggested that these changes represent physiological adaptations to chronic cold. Submitted on November 14, 1960
Some physiological changes accompanying tetany induced by exposure to hot, wet conditions
Authors: Iampietro P. F. , Mager M. , Green E. B. 
Published: December 2017

Twenty-seven men were exposed to various hot, wet conditions for a total of 87 experiments. Determinations were made of rectal temperature, heart rate, blood pH, and the concentrations of CO2, calcium, inorganic phosphorus, and protein in plasma. Symptoms ranging from tingling of extremities to carpopedal spasms were observed. The frequency and severity of symptoms were apparently not related to the absolute change in any of the blood constituents but rather to the rate of change. Submitted on October 31, 1960
Some physiological responses of man to workload and environment
Authors: Suggs C. W. , Splinter W. E. 
Published: December 2017

The heart rate, ventilation rate, oxygen consumption rate, and mechanical efficiency responses of a subject to a series of temperatures, relative humidities, and workloads were observed. A quadratic prediction equation of each of the responses as steady-state functions of the independent variables was derived. Each of the equations represents a four-dimensional hypersurface. For the heart rate, ventilation rate, and oxygen consumption rate the hypersurfaces are quite similar, the responses increasing rapidly with respect to workload and about one-third as rapidly with respect to temperature. The effect of relative humidity was present primarily as interactions. Mechanical efficiency was represented by a more complex hypersurface. In three dimensions, with relative humidity as a parameter, the response was a saddle-shaped surface with the highest efficiency at a condition of low temperature, high workload. At constant environment, the heart rate responses of 19 subjects to workloads was observed and found to be linear with a normal distribution of slopes. Submitted on May 2, 1960
Transmission of elastic disturbances caused by air shock waves in a living body
Authors: Clemedson Carl-Johan , Jönsson Arne 
Published: December 2017

Anesthetized rabbits were exposed to air shock waves in a detonation chamber. The pressure wave patterns were recorded by means of a small lead zirconate titanate pressure transducer in the following parts of the body: at and under the skin of the side facing the charge, in the pleural sac and in the lung of that side, in the right and left ventricle of the heart, in the lung and in the pleural sac on the side opposite the charge, under the skin of that side, in the stomach, and in the skull between the bone and the brain. When the incident shock wave is propagated through the body the very steep shock front is converted so that the ascending limb of the pressure peak is much less steep, with a duration up to several hundred microseconds. The longest periods of pressure rise were found in the heart ventricles and stomach. The amplitude of the pressure curve generally diminishes as the wave passes through the body. The changes of the original shock wave are due probably in great part to the inhomogeneous structure of the animal body. Note: (With the Technical Assistance of A.-B. Sundqvist) Submitted on October 24, 1960
Total CO2, Pco2, and pH in human spinal fluid
Authors: Merril Carl R. , Seipp Harry W. , Luchsinger Peter C. 
Published: December 2017

The relationships between pH, CO, tension and total CO2 in spinal fluid and arterial blood were explored in 12 normal individuals and 15 patients with various diseases. It was found that, in the normal subjects, the pH in the spinal fluid was constant, with a mean of 7.31 and 99 % confidence interval of 7.29–7.33. The pH in the spinal fluid was lower than that of the arterial blood in all patients studied, whereas the CO2 tension was found to average 4 mm Hg higher in the spinal fluid than in the arterial blood in most of the normal subjects studied. The pK1' was calculated for each patient's spinal fluid and arterial blood by the Henderson-Hasselbalch equation. In contrast to tonometry experiments, pK1' showed marked individual variations. The factors responsible for these variations are delineated. Submitted on November 7, 1960
Effects of chlorothiazide on forearm vascular responses to norepinephrine
Authors: Feisal Khalil A. , Eckstein John W. , Horsley A. W. , Keasling Hugh H. 
Published: December 2017

The effects of graded doses of norepinephrine on pulse rate, mean blood pressure, forearm blood flow and vascular resistance were studied in normal human subjects before, during, and after chronic administration of chlorothiazide. This drug prevented the negative chronotropic response normally induced by norepinephrine without altering the pressor response. Before giving and after discontinuing chlorothiazide, increasing doses of norepinephrine were associated with progressive decreases in blood flow. After 1 week of chlorothiazide administration, increasing doses of norepinephrine were associated with increases in flow. The results indicate that chlorothiazide decreases the responsiveness of the forearm vessels of normal subjects to the vasoconstrictor effect of norepinephrine. They suggest that chlorothiazide also may modify the effect of norepinephrine on cardiac output. Submitted on December 9, 1960
Red cell and plasma volumes of the rat and of tissues during cold acclimation
Authors: Everett Newton B. , Matson Lorna 
Published: December 2017

Red cell and plasma volumes of the total rat and of its individual tissues and organs were determined for animals exposed to 5 C for 4 hr, 24 hr, 2 weeks, and 6 weeks. In addition, the tissue hematocrit ratios were determined. These values were compared with those of rats kept at 24 C. Fe59-labeled erythrocytes and I131-labeled albumin were given intravenously, and after mixing the rats were frozen in liquid nitrogen. The organs and tissues were removed in the frozen state, assayed for radioactivity, and blood cell and plasma volumes were calculated on a unit weight basis. Significant changes in blood cell and plasma volumes were observed for the total rat and for many of the individual organs. There was a significant increase in the red cell content of the total rat within 24 hr of cold exposure. After 6 weeks, total blood volume was increased by approximately 20% over the control level and the increase in erythrocyte volume was slightly more than the increase in plasma volume. The hematocrit ratio of heart blood was 44.8 after 6 weeks exposure compared with 41.5 for controls. In general, it can be said that the somatic parts of the body showed increases in blood volume whereas the visceral parts had decreased volumes. Submitted on August 15, 1960
Effects of handling on weight gains and endocrine organs in mature male rats
Authors: Weltman A. Stanley , Sackler Arthur M. , Gennis Joseph 
Published: December 2017

Daily handling of young mature rats over a 3-week period significantly increases their body weight gains in much the same fashion as does the handling of preweanling and weanling rats. Significant increases were also observed in the adrenals, testes, seminal vesicles, spleen and liver organ weights. Although mechanisms involved in the handling effect are not clearly defined, the findings have methodologic significance. The marked influence of handling on weight gains and organ weights indicates the need for careful regulation of the handling of control and experimental animals in all endocrine studies. The study indicates that the stimulatory effects of handling on body growth and development are not necessarily limited to the early developmental period. Submitted on December 22, 1960
Sweating in hot baths
Authors: Hertig Bruce A. , Riedesel Marvin L. , Belding Harwood S. 
Published: December 2017

Sweating of human volunteers immersed to the neck in hot water declined markedly after reaching a peak in the 1st hr of exposure. This decline always occurred in fresh water regardless of level of thermal stress. Sweating in the 3rd hr of exposure was about the same whether the water was hot in the 1st 2 hr (sweat glands active) or cool (sweat glands inactive). Thus “fatigue” was not responsible for the decline. It is suggested that observations of decline of sweating in warm-humid air environments, attributed to “sweat gland fatigue,” in reality may have been owing to soaking of the skin with sweat. The mechanism of suppression appears more complex than blockage of the sweat ducts by swelling of the corneum. Rather, there is an association between the amount of decline and conditions favoring diffusion of water to deeper strata of the skin. For example, adding salt to the water reduced the decline; no decline occurred in 15% NaCl. Submitted on March 6, 1961
Mechanism of epinephrine-induced eccrine sweating in human skin
Authors: Hurley Harry J. , Witkowski Joseph A. 
Published: December 2017

The mechanism of local epinephrine-induced eccrine sweating was examined in five healthy white males using a recently developed method employing methylene blue excretion by the sweat glands as an indicator of eccrine secretory activity. Excretion in eccrine sweat of the intradermally introduced methylene blue was observed in all of the subjects with both adrenergic (epinephrine, norepinephrine) and cholinergic (acetylcholine, pilocarpine) stimulation. This observation indicates that local adrenergic eccrine sweating is not due merely to myoepithelial expression of preformed eccrine sweat but results from active secretion of sweat, as do other types of eccrine sweating. Submitted on January 30, 1961