bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary capillary blood volume in dog: effects of 5-hydroxytryptamine
Authors: Young Roscoe C. , Nagano Hitoshi , Vaughan Thomas R. , Staub Norman C. 
Published: December 2017

We studied changes in pulmonary capillary blood volume (Vc) in anesthetized dogs to determine whether 5-HT (5-hydroxytryptamine) constricts pulmonary venules. The preparation was sufficiently stable to allow reproducible measurement of pulmonary diffusing capacity (Dl). A fixed volume of CO gas mixture was introduced into the lungs by positive pressure, and an alveolar sample was obtained after 10 sec. By measuring Dl at different levels of Pao2, a value proportional to Vc was obtained. We cannot give absolute values for Vc since the rate at which CO replaces O2 in red cells in dogs is unknown. In 10 of 14 dogs given 5-HT, Vc increased 6 to 133%. There were no differences in left ventricular diastolic, systemic arterial, or airway pressures. Changes in blood flow were unrelated to changes in Vc. These findings are independent evidence that 5-HT causes pulmonary venous constriction, which in turn leads to passive congestion of the pulmonary capillary bed. Submitted on July 5, 1962
Diving pattern, lung volumes, and alveolar gas of the Korean diving woman (ama)
Authors: Hong S. K. , Rahn H. , Kang D. H. , Song S. H. , Kang B. S. 
Published: December 2017

Lung volumes and alveolar gases during actual dives were studied in the Korean diving women, or ama. These women dive without assistance. Average descent and ascent velocities are 0.6 m/sec. Maximal depth and duration of dive observed were 17 m and 82 sec, respectively. However, typical sustained diving activity is to a depth of 5 m for 30 sec, averaging 60 dives/hr. This diving pattern is compared with the assisted dives of the Japanese ama lasting 60 sec and reaching a depth of about 20 m. Prior to diving the lung is filled to 85% of vital capacity. About 700 ml of this gas are lost upon return to the surface. A slight hyperventilation before dive reduces the Pco2 to 28. At the bottom the fractional composition of O2 as well as CO2 is less than before dive indicating that both gases are removed by the circulation. The compression of the gases accounts for the reversal of CO2 transport. Upon return to the surface CO2 leaves the blood and reaches normal values while the O2 is very low. At the bottom O2 pressure is high due to compression but falls rapidly upon ascent. The detailed pattern of gas exchange is discussed. Submitted on September 28, 1962
Effects of continuous administration of angiotensin II on ventricular performance
Authors: Downing S. Evans , Sonnenblick Edmund H. 
Published: December 2017

The effects of angiotensin II on circulatory dynamics and coronary blood flow were studied in the cat. With equal single doses of angiotensin II and norepinephrine a greater blood pressure response occurred with angiotensin. With continuous administration of angiotensin II a large initial blood pressure response occurred, but rapidly returned to an intermediate value. During this time the animal was refractory to further single doses. A sustained large increase of ventricular contractility was readily demonstrated with the continuous administration of norepinephrine, but could not be demonstrated with equal amounts of angiotensin II. Acute transient changes of ventricular contractility were observed. Frequently an acute increase of both stroke work at a given filling pressure, and mean rate of ejection occurred. Occasionally, however, marked acute myocardial depression, which rapidly returned to control values, was observed. In about one-third of the preparations prolonged myocardial depression was observed following a period of continuous angiotensin II infusion. This was in sharp contrast to continuous norepinephrine infusion following which myocardial depression was never observed. Measurements of coronary blood flow indicated that when ventricular work was maintained constant, continuous angiotensin II infusion was frequently associated with a transient reduction of coronary flow. This was usually small, but occasionally marked. During this phase concomitant myocardial depression was evident. Continuous norepinephrine infusion produced only an increase of coronary blood flow with an associated increase of myocardial contractility. Submitted on October 11, 1962
Effect of muscular exercise on plasma viscosity in correlation with postprandial triglyceridemia
Authors: Konttinen Aarne , Somer Timo 
Published: December 2017

The correlation between postprandial triglyceridemia and plasma viscosity was studied in 45 healthy young men. One-half, 23, of them carried out a heavy march lasting 2 hr while the other half, 22, rested in bed. Serum triglycerides and plasma viscosity were determined before the fat meal and 4 and 6 hr postprandially. Serum total proteins and hematocrits were measured simultaneously. Despite significantly higher postprandial triglyceridemia in the resting group no rise was seen in plasma viscosity, whereas, in the exercise group with a lower triglyceride level a significant elevation took place in plasma viscosity. serum triglycerides Submitted on February 18, 1963
Calcium phosphorus metabolism in man during acclimatization to carbon dioxide
Authors: Schaefer K. E. , Nichols G. , Carey C. R. 
Published: December 2017

The calcium phosphorus metabolism was studied in 20 subjects who were exposed for 42 days to 1.5% CO2. Plasma calcium mirrored the changes of the pH, showing a decrease during the first 23 days of exposure, a return to initial levels during the latter part of exposure, a marked rise above control values during the 8–9 day recovery period following exposure, and a return to normal values after 4 weeks of recovery. Changes in plasma calcium were found to correspond to changes in pulmonary CO2 excretion indicating a significant role of bone CO2 stores in acclimatization and deacclimatization of carbon dioxide. Plasma inorganic phosphorus was elevated throughout the exposure period and recovery period. At the end of the exposure period to CO2 red cell calcium had increased and red cell phosphorus had decreased. After 9 days, as well as after 4 weeks, of recovery on air the calcium content of the red cells continued to increase and the inorganic phosphorus values remained lowered. chronic respiratory acidosis; chronic hypercapnia Submitted on November 2, 1961
Human cerebral circulation during deliberate hypotension and head-up tilt
Authors: Eckenhoff James E. , Enderby G. E. Hale , Larson Alex , Davies Russell , Judevine Donald E. 
Published: December 2017

Forty-two patients for elective surgical procedures were anesthetized with thiopental, nitrous oxide, and halothane and made hypotensive by ganglionic blockade with pentolinium, hexamethonium, trimethaphan, and/or guanethidine, combined with head-up body tilt, with or without positive airway pressure. In 23 patients, the systolic arterial pressure was at or below 70 mm Hg for an average of 42 min. In six patients, the systolic pressure was 50 mm Hg or below for an average of 39 min with an average head-up tilt of 24°. The lowest jugular bulb Po2 recorded during hypotension was 27 mm Hg except in six instances when lower figures were recorded in the presence of increased airway pressure. Jugular bulb Po2 was better correlated with PaCOCO2 (r = 0.79) than with arterial pressure (r = 0.56). In the head-up position, jugular bulb pressures were usually above atmospheric pressure and were related to arterial carbon dioxide tension (r = 0.58). Cerebrovascular compensation appeared adequate under the conditions of deliberate hypotension as produced with this technique. hypotension during anesthesia; hypercapnia during hypotension; cerebral venous pressures; pulse waves Submitted on March 4, 1963
Regulation of breathing at beginning of exercise
Authors: Craig F. N. , Cummings E. G. , Blevins W. V. 
Published: December 2017

In initial 20-sec periods of running on the treadmill, raising the slope to 12% increased by 50% the integrated muscle action potential, recorded from the under side of the thigh, without affecting the ventilation in four men. Five men worked for 1 min at four tasks, two on the treadmill and two on the horizontal cycle ergometer. Each pair of tasks consisted of slow and rapid leg movement at the same rate of work. Ventilation often continued at about the resting rate for the first few seconds of work, unaffected in any significant way by frequency of leg movement. In the subject responding to the onset of exercise by a sudden sharp involuntary increase in ventilation, the nature of the nervous respiratory drive is not clear. Whatever drive arises from the work itself may be strongly modified by training or by complexities in the work situation. leg movement; muscle action potential; nervous respiratory drive Submitted on May 16, 1963
Circulation in exercising dogs
Authors: Cerretelli P. , Piiper J. , Mangili F. , Cuttica F. , Ricci B. 
Published: December 2017

The adjustments of the cardiovascular system to muscular exercise were studied in dogs running on a treadmill at different speeds and at the incline of +10%. The cardiac output, measured by the thermodilution method, increased with increasing O2 consumption, reaching 520 ml/kg min at an O2 consumption of 70 ml/kg min. At still higher metabolic levels the cardiac output remained constant and the O2 consumption increased by an increase of the arteriovenous O2 difference only, which was calculated to attain 17 vol % at the highest O2 consumption value reached in this study, 90 ml/kg min. The increase of the cardiac output was mainly due to increase of the heart rate, whereas the average maximum increment of the stroke volume was about 30% only. The mean arterial and the central venous blood pressures increased with exercise. The time course of the adjustment of the cardiac output was measured after the exercise of varied intensity had been abruptly begun or stopped. Both for start and recovery the “half reaction time” was about 20 sec; after 1 min no further measurable change of the cardiac output was detectable. cardiac output and O2 consumption at increasing metabolic levels; heart rate and stroke volume in running dogs recovery following exercise Submitted on July 15, 1963
Thermal balance and biogenic amine excretion in Gaspé fishermen exposed to cold
Authors: Leblanc Jacques , Pouliot M. , Rheaume S. 
Published: December 2017

Previous studies have shown a decreased response in fishermen to cold applied locally. In the present study, the same subjects, when exposed naked for 1 hr at 60 F maintained a higher skin temperature than a control group. If these findings indicate a decreased vasoconstriction, all results obtained to date on these fishermen would indicate a decreased adrenergic response. Evidence of gross shivering was much more pronounced in the fishermen but this was not reflected by greater heat production. Both groups excreted more hydroxycortisone in the cold, and the excretion was higher in the control subjects. Cold exposure did not increase the catecholamine excretion in either group. Note: (With the Technical Assistance of P. Tousignant) acclimatization; body temperature; skin temperature; vasomotor adaptation; shivering; adrenergic response in cold habituation; hydroxycortisone excretion in cold stress Submitted on June 17, 1963
Maximum ventilatory performance and its limiting factors
Authors: Shapiro William , Johnston C. E. , Dameron R. A. , Patterson J. L. 
Published: December 2017

Pressure-volume-flow relationships during maximum-effort expirations and inspirations were analyzed in 27 studies on 7 superbly conditioned nonsmoking athletes, 5 nonathletic nonsmokers, and 7 nonathletic smokers. The athletes had larger mean vital capacity and maximum breathing capacity as well as higher airflow during the first half of forced inspiration than the other subjects. In contrast, smokers exhibited lower mean vital capacity, lower air flows, and higher transpulmonary pressures during forced expirations than the nonsmokers. Transpulmonary pressures at peak flow during maximal forced expirations were higher in the present study than those commonly reported and may have been due to the technique used to perform this maneuver. Limiting factors apparently operate to prevent superior athletic conditioning from effecting comparable improvement in ventilatory performance. The favorable alterations in this performance which were observed in the athletes do not seem sufficient to explain their greater endurance. Mild decreases in ventilatory performance were exhibited by the smokers, probably due to the chronic effects of cigarette smoking on the pulmonary airways. respiratory pressure-volume-flow relationships; vital capacity and maximum breathing capacity in athletes; esophageal balloon system for measuring transpulmonary pressure Submitted on April 25, 1963
Respiratory thoraco-abdominal mechanics in man
Authors: Milic-Emili Joseph , Orzalesi Marcello M. , Cook Charles D. , Turner James M. 
Published: December 2017

The behavior of the diaphragm and the thoracic and abdominal muscles during various static and dynamic respiratory maneuvers was studied in six trained men by measuring intrathoracic (esophageal) and intra-abdominal (gastric) pressures together with lung volumes. The static maneuvers included voluntary relaxation of respiratory muscles, maximal inspiratory and expiratory efforts, and maximal abdominal expulsive efforts. The dynamic maneuvers were forced inspiratory and expiratory vital capacities and maximal voluntary ventilation. The patterns during the various respiratory maneuvers were relatively uniform. Although the number of subjects studied was small, our results would appear to give a general description of thoraco-abdominal mechanics, at least in trained subjects. breathing patterns; static respiratory maneuvers; maximal voluntary ventilation; forced inspiration and expiration; dynamic respiratory maneuvers; abdominal pressures and thoracic pressures at varying lung volumes Submitted on May 13, 1963
Simultaneous and rapidly repeated cardiac output determinations by dye-dilution method
Authors: Hanson John S. , Tabakin Burton S. 
Published: December 2017

Reproducibility of cardiac output determinations by dye dilution at rest and during graded treadmill exercise has been assessed by means of simultaneous, rapidly repeated measurements with two Waters 250-A densitometers at both a single sampling site and from both arms. A total of 232 paired-dilution curves was recorded from 10 normal subjects with both densitometers sampling from the same radial artery, and 158 curves from 9 subjects, one densitometer sampling each radial artery simultaneously. Measurements were made with subjects recumbent and during walking varying from level to a 12° treadmill elevation. With both densitometers sampling the same arterial stream cardiac output variation from the two instruments progressively increased from 7% (0.562 liter/min) at rest to 11% (2.773 liter/min) at peak exercise as represented by a standard deviation of the difference related to mean cardiac output. When two arterial streams were being sampled for each injection, variation between instruments amounted to 9–12% of mean cardiac output. Significantly greater variation was observed in curves obtained within 1 min of each other from the same densitometer. measurement of cardiac output during exercise; cardiac output technique; variation in dye-dilution technique; bilateral cardiac output measurements; upright treadmill exercise Submitted on July 12, 1963
Octanoic acid absorption and oxidation in humans
Authors: Schwabe Arthur D. , Bennett Leslie R. , Bowman Lance P. 
Published: December 2017

The absorption and oxidation of carboxyl-labeled octanoic acid as determined by monitoring of expired C14O2 was studied in 27 subjects. In 12 normal volunteers there was no significant difference in the recovery of C14O2after oral and intravenous administration of the isotopically labeled octanoic acid. Administration of 100 g glucose by mouth did not seem to inhibit octanoic acid oxidation in ten subjects. Infusion of 1 g unlabeled octanoate also did not significantly affect the oxidation of radioactive octanoate in five subjects. These observations in humans tend to confirm animal studies which have shown that octanoic acid is well absorbed from the gastrointestinal tract and rapidly oxidized. The oxidation of small amounts of this fatty acid appears to proceed at the same rate despite moderate blood levels of glucose or octanoic acid. These characteristics of short chain fatty acid absorption and oxidation can be exploited in the study of fat absorption in human subjects. intestinal absorption; fatty acid metabolism Submitted on August 14, 1963
Rapid-responding carbon dioxide and oxygen electrodes
Authors: Fatt Irving 
Published: December 2017

Redesign of the Severinghaus pCO2 and the Clark pO2 electrodes yields electrodes which are easier to make and assemble. When used with a new membrane material, paraffin-treated Millipore filter paper, the redesigned Severinghaus pCO2 electrode gives 99% response in 15 sec for a 40 mm Hg change in pCO2 in the region of 15–60 mm Hg pCO2 in either gas or water phase. The redesigned Clark pO2 electrode when used with treated Millipore paper gives 99% of final response in 1.24 sec for a 155 mm Hg change of pO2 in the gas phase in the range 0–160 mm Hg pO2. In aqueous solutions this electrode gives 99% response in 30 sec. Severinghaus electrode; polarographic oxygen electrode; pCO2 measurement; pO2 measurement Submitted on March 19, 1963
Effect of intra-alveolar fluid on pulmonary surface tension properties
Authors: Johnson John W. C. , Permutt S. , Sipple John H. , Salem El Sayed 
Published: December 2017

In 17 anesthetized dogs, 50–150 ml of isotonic saline or human amniotic fluid were instilled into a degassed lobe and after 2–6 hr of spontaneous or artificial ventilation, the lungs were excised. Static pressure-volume and extract surface tension values were then determined on a fluid- and a nonfluid-instilled lobe from each animal. When compared with nonfluid-instilled lobes the fluid-instilled lobes were found to have proportionately smaller volumes at maximum inflation ( P < .02) and during deflation ( P < .001) as well as regional areas with higher surface tension properties ( P < .001). It is proposed that the pressure-volume studies may furnish a useful means of assessing the anatomical extent of alterations in lung surface tension. There was a significant negative correlation between maximum inflation volumes and maximum surface tensions ( P < .001) as well as between the volumes during deflation and the minimum surface tensions ( P < .001). It is concluded that intra-alveolar fluid may inactivate or displace the surface-active material from the alveolar lining membrane. amniotic fluid; lung pressure-volume studies; lung surfactant Submitted on April 11, 1963
Anticipatory, exercise, and recovery heart rates of girls as affected by four running events
Authors: Skubic Vera , Hilgendorf Jane 
Published: December 2017

The heart rate response to running various distances was studied using five highly trained girls as subjects. A telemetering instrument was employed so that the testing could be done under actual sport conditions. The findings indicated that 1) the anticipatory heart rate just prior to exercise represented 59% of the total adjustment to exercise, 2) the heart rates during exercise were 2.5 times the resting values, and 3) heart rates observed at the end of the 220-, 440-, 880-yard, and mile events were simila cardiac function; exercise Submitted on October 22, 1963
Carbon dioxide and pulmonary ventilation in muscular exercise
Authors: Kao F. F. , Michel C. C. , Mei S. S. 
Published: December 2017

The effect of endogenous CO2 from exercising muscles and exogenous CO2 from CO2 inhalation was investigated in six pairs of cross-circulated dogs. The exercising hindlimbs of one dog (neural) were perfused exclusively from a second dog (humoral). The ventilatory response of the neural dog during exercise followed the predicted isometabolic hyperbola toward hyperventilation, whereas the ventilation of the humoral dog followed closely the relationship which existed between V and PaCOCO2 during CO2 inhalation. When the neural dog was given CO2 mixtures during steady state of induced exercise, its ventilation increased in a rectilinear function of the PaCOCO2. The V, PaCOCO2 line intersects the isometabolic curve for the exercise level at a PaCOCO2 close to the resting PaCOCO2. A metabolic acidosis developed in the humoral dog, although the blood flow to the perfused hindlimbs appeared to be adequate during muscular exercise. cross perfusion; neural control of respiration; humoral control of respiration; CO2 inhalation; muscle blood flow in exercise; perfusion of leg muscle Submitted on February 19, 1964
Use of heart rate for evaluating cardiac strain during training in women
Authors: Maxfield Mary E. 
Published: December 2017

The usefulness of heart rate information to measure cardiac performance is demonstrated for young women during physical training. Data were studied in terms of rate, total number of beats (cardiac cost), and recovery phenomena. Provided work remained constant, training decreased the heart rate during both work and recovery, with corresponding reduction in the sum of beats (total cardiac cost). If working rates are not obtainable, recovery rates as 1) the sum of beats (recovery cost) or 2) Pavg 1, 2, 3, the average of counts taken during the last 30 sec of the 1st, 2nd, and 3rd min of the recovery period, can substitute for total cost as a measure of cardiac performance. The effect of increasing the work accomplished upon cardiac cost and Pavg 1, 2, 3 is discussed and use of a comparative “standard” for assessing cardiac strain from the value of Pavg 1, 2, 3 is suggested. physical training; work; heart rate; cardiac cost; recovery pulse evaluation; human female Submitted on March 17, 1964
Effect of carbon dioxide on heart rate
Authors: Mithoefer John C. , Kazemi Homayoun 
Published: December 2017

Pentobarbital, by its sympathomimetic effect, produces tachycardia in the dog which is slowed by hypercapnia. The parasympathomimetic effect of chloralose anesthesia, in the intact dog, results in a slow heart rate which is increased by hypercapnia. This opposite response to CO2 appears related to the opposite autonomic effects of the two agents, since when tachycardia is induced in dogs anesthetized with chloralose, they then respond to hypercapnia by cardiac slowing. In experiments reported here and in data available in the literature, there appears to be a correlation between prehypercapnic heart rate and the chronotropic effect of CO2. Results reported here suggest that cardiac slowing by hypercapnia occurs through a direct effect of CO2 rather than pH and that the mechanism has both central and peripheral mediation; the former transmitted by vagal pathway with a specific site of action at the sinus node. hypercapnia; effect of anesthetics; mechanism of action; CO2-site of action; interaction between initial rate and rate response Submitted on May 14, 1964