bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ventilatory response to intermittent inspired carbon dioxide
Authors: Dutton R. E. , Chernick V. , Moses H. , Bromberger-Barnea B. , Permutt S. , Riley R. L. 
Published: December 2017

The hypothesis that cyclic variation of CO2 tension of the arterial blood (PaCOCO2) about its mean produces an additional stimulus to ventilation was tested in the dog. Oscillations of alveolar carbon dioxide tension were produced by the intermittent administration of 20% CO2 for 1 breath every 7–12 breaths. The increment in ventilation per mm Hg rise in mean PaCOCO2 during the intermittent administration of 20% CO2 was compared to that during continuous administration of 3% CO2 in nine adult dogs anesthesized with sodium pentobarbital. Thirteen experiments with oscillating CO2 and eighteen with steady CO2 were performed. In all except one animal the increase in ventilation per mm Hg change in mean PaCOCO2 was greater during intermittent CO2 than during steady CO2. In three experiments intermittent administration of CO2 caused a ventilatory response sufficient to lower the mean PaCOCO2 below control values. The increment in total ventilation per mm Hg rise in arterial carbon dioxide tension for steady CO2 breathing was 0.58 liters/min per mm Hg and for intermittent CO2 was 2.00 liters/min per mm Hg. These findings support the concept that chemoreceptors are stimulated by oscillations of PaCOCO2 as well as by the mean level of PaCOCO2. The oscillatory stimulus appears not to be related to the amplitude of the oscillation or to the peak Pco2 attained, but rather to the rate of increase of arterial Pco2. respiration control; ventilation Submitted on October 17, 1963
Experimental evaluation of Weir's formula for estimating metabolic rate in man
Authors: Turell David J. , Alexander James K. 
Published: December 2017

One hundred and thirty determinations of metabolic rate at rest and during both steady and unsteady states of exercise have been made in human subjects. Calculation of the caloric expenditure by means of Weir's formula, by the Zuntz-Schumburg-Lusk table, and by the Cathcart-Cuthbertson table has revealed mean differences among these methods of less than 1%. The Weir formula may be utilized for all practical purposes in lieu of the tables, permitting elimination of the RQ correction factor, and thus simplifying the estimation of the energy cost of activity caloric expenditure; determination of metabolism; formula for caloric expenditure; steady-state, caloric measurement; unsteady-state, caloric measurement Submitted on December 16, 1963
Chronic bile duct cannulation in the dog
Authors: Marshall Richard W. , Moreno Oscar M. , Brodie David A. 
Published: December 2017

Chronic bile duct cannulation for periods of up to 6 months was obtained by catheterizing the bile duct in cholecystectomized dogs with plastic tubing without ligation of the bile duct. Between experiments, the bile drained into the intestine and during experiments, the plastic tube was removed through a chronic duodenal cannula. Similar bile volumes were obtained over a 24-hr collection period whether or not the bile was reintroduced into the intestine. bile collection in chronic dogs; 24-hr bile volume Submitted on February 28, 1964
Catheter-tip flowmeter for coronary arterial flow in closed-chest dogs
Authors: Pieper Heinz P. 
Published: December 2017

The design of a catheter-tip flowmeter for the measurement of coronary arterial blood flow in closed-chest dogs is presented. The miniaturized flowmeter is attached to the tip of a rigid catheter which is inserted through the right carotid artery. The flowmeter is placed in the ascending aorta where it measures the inflow into the left coronary artery. Performance tests show the reliability of the instrument for the measurement of pulsatile flow. pulsatile flow Submitted on February 3, 1964
Effect of respiratory gases on compliance of intrapulmonary arteries and veins
Authors: Salem E. S. , Permutt S. , Riley R. L. , Johnson J. W. C. 
Published: December 2017

Submitted 16 October 1964 A method was developed that permitted changes in the pressure-volume characteristics of large intrapulmonary vessels occurring with changes in the composition of alveolar gas to be studied in excised lungs. The capillary bed was emptied by keeping intravascular pressure well below alveolar pressure, and the relationship between changes in the volume of the pulmonary arteries or veins with changes in transpulmonary pressure was measured. The volume of the arteries and veins always decreased with a decrease in transpulmonary pressure, but when the alveoli contained carbon dioxide, the decrease in vascular volume was less, for the same decrease in transpulmonary pressure, than when the alveoli contained oxygen or nitrogen without carbon dioxide. This change with carbon dioxide was probably due to a decrease in the compliance of the larger intrapulmonary arteries and veins. Since there was no pathway for carbon dioxide to enter these vessels except by diffusion from the alveoli, it is concluded that carbon dioxide can act directly on the intrapulmonary arteries and veins to reduce their compliance, but it is not known whether this effect has physiological significance. No effect on the large pulmonary vessels was found with variations in alveolar concentrations of oxygen. blood vesselsblood volumecarbon dioxidediffusionlungspulmonary circulation
Acid-base constants and temperature coefficients for cerebrospinal fluid
Authors: Mitchell Robert A. , Herbert Dorothy A. , Carman Charles T. 
Published: December 2017

The solubility of CO2 in human cerebrospinal fluid (CSF) is 0.0312 mmole/liter·mm Hg at 38 C. The first dissociation constant (pK1') of carbonic acid at 38 C is 6.130 at pH 7.30 and varies inversely with pH and temperature. At pH 7.30 DeltapK1'/ DeltapH is -0.050 and DeltapK1'/DeltaT is-0.0029 U/°C. pH of CSF varies inversely with temperature over the range of pH from 6.9 to 7.7. DeltapH/DeltaT is -0.0037 U/°C. The temperature correction for CSF Pco2 is expressed Pco2T1/Pco2T2 = 10 f(T1–T2) At pH 7.30, f is 0.0110. The effect of varying Pco2 on pH in vitro at 38°C, expressed as Delta log Pco2/DeltapH, is 1.063 ± 0.022. first dissociation constant; CO2 solubility; CSF buffering Submitted on February 20, 1964
A simple method for measuring total respiratory compliance: normal values for males
Authors: Cherniack R. M. , Brown E. 
Published: December 2017

A simple method for measuring the compliance of the total respiratory system utilizing a recording spirometer and lead weights is described. The method was reproducible and compared well with an established body box technique. The compliance of the total respiratory system was determined in 70 normal male subjects between the ages of 4 and 70. The total respiratory compliance was influenced by age and appeared to rise during the first 3 decades and fall in subsequent decades. The compliance was also related to the height, body surface area, total lung capacity, and vital capacity, the best correlation being with vital capacity. The change in compliance with age did not appear to be related to change in body size. When corrected for the total capacity of the lungs, there was a gradual decrease in total compliance with aging. It is suggested that this is due to an increase in resistance of the “chest wall.” compliance and age and size; compliance and lung volumes Submitted on April 1, 1964
Lung diffusing capacity: rebreathing method, applicability in nonuniform ventilation
Authors: S⊘lvsteen P. 
Published: December 2017

We have calculated how the carbon monoxide concentration changes when subjects with different distributions of ventilation and lung diffusing capacity (Dl) respire in a small bag. The curve [loge CO concentration in the bag] versus [time] will sooner or later appear as a straight line. Dl is calculated from the slope of the rectilinear section of the curve and from lung and bag volume. If the curve becomes rectilinear within the period considered, Dl is calculated too low. In some cases the curve will not be rectilinear until more than 45 sec have passed, but will appear to be rectilinear during the period from 30 to 45 sec. If such an experiment is discontinued when 45 sec (the usual duration of experiment) have passed, Dl can be calculated at too high, at correct, or at too low values. nonuniform distribution of lung diffusing capacity Submitted on February 18, 1964
Regional distribution of intraesophageal pressure in normal and emphysematous subjects
Authors: Schilder Donald P. , Roberts Albert , Greenfield Joseph C. , Fry Donald L. 
Published: December 2017

If sufficiently large pressure differences were to develop between the pulmonary air spaces of one region and another during ventilatory efforts, then it is possible that septal ruptures such as seen in emphysema might result. It was the purpose of this study to explore this possibility. Intraoral airway pressure and intraesophageal pressure at three esophageal levels were measured simultaneously and continuously in 5 normal subjects and 10 patients with varying degrees of chronic obstructive pulmonary disease. No significant regional pressure difference developed in the segments of lung adjacent to the esophagus in any subject during static respiratory efforts against a closed valve or during strenuous dynamic respiration with maximum voluntary ventilation. These results are negative with respect to the pathogenesis of emphysema since large pressure differences along the lung surface were not demonstrated. The remarkable similarity of intraoral airway pressure and the intraesophageal pressures during the static part of the study is further evidence validating the intraesophageal approach to the measurement of intrathoracic pressure in diseased as well as normal subjects. intrathoracic pressure; lung stress mechanics of ventilation; pathogenesis of emphysema Submitted on June 9, 1964
Pulmonary circulation in acclimatized man at high altitude
Authors: Hultgren H. N. , Kelly J. , Miller H. 
Published: December 2017

Cardiac catheterization studies have been carried out in 30 acclimatized adults at an altitude of 12,3000 ft in the Peruvian Andes. Mean pulmonary artery pressure was 22 mm. Hg (range 14-31 mm Hg) compared to 15 mm Hg (range 11-17 mm Hg) observed in sea-level subjects. The pulmonary artery wedge pressure was normal and calculated pulmonary arteriolar resistance was increased by 180% over sea-level values. The arteriovenous oxygen content difference and oxygen consumption were slightly greater at high altitude, but the cardiac output was normal. There was no relationship between hematocrit and pulmonary artery pressure or resistance, suggesting that in the high-altitude resident, blood viscosity in a hematocrit range of 40-78% does not significantly affect resistance to blood flow. Nine subjects studied at 14,200 ft had the same mean pulmonary artery pressure (22 mm Hg, range 17-32 mm Hg) as the larger group at 12,300 ft. pulmonary artery pressure Submitted on May 8, 1964
Oral/rectal temperature differences during work and heat stress
Authors: Strydom N. B. , Wyndham C. H. , Williams C. G. , Morrison J. F. , Bredell G. A. G. , Joffe A. 
Published: December 2017

Fifty-two groups of about 20 men each were exposed for 5 hr to various combinations of work rate, environmental temperature, and wind velocity. Hourly observations were made of oxygen intake and oral and rectal temperatures. Oral/rectal temperature differences increased significantly with time only under those conditions where steady-state responses were not achieved. Increasing wind velocity from 50 to 400 cm/sec, raising air temperatures from 27 to 36 C, and combinations of these factors had no significant influence on the difference between the recorded temperatures. The main contributing factor to oral/rectal temperature difference is work rate. Increasing energy consumption from 2.5 to 9.0 Cal/min resulted in a rectilinear increase in average difference from 0.5 to 1.1 C. A warning is expressed against the indiscriminate use of oral temperatures in work and heat studies influence of work and heat stress on oral/rectal temperature differences; oral versus rectal temperatures Submitted on May 18, 1964
Effects of exercise in the cold on blood clotting and platelets
Authors: Finkel Annette , Cumming G. R. 
Published: December 2017

The tendency to blood clotting as measured by Lee-White clotting time (CT), partial thromboplastin time (PTT), and platelet adhesiveness (PAC) was studied in 10 normal subjects before and after a standardized bicycle exercise done at 25 C inside and at an average temperature of -20 C outside. Inside exercise caused a shortening of CT from 674 to 465 sec, of PTT from 88 to 78 sec, and PAC increased from 65,000/mm3 to 185,000/mm3; P < .05 for all tests, suggesting an increased tendency to blood clotting. In contrast, exercise done in the cold produced no significant changes in these parameters. Heart rate, rectal temperature, and changes in plasma proteins were similar for both types of exercise. platelet adhesiveness; clotting time Submitted on July 20, 1964
Dissimilar distribution of calcium isotopes in blood serum and urine
Authors: Briscoe Anne M. , Ragan Charles 
Published: December 2017

A study of the distribution of tracer doses of radiocalcium 47 in blood serum and urine for 5 days after its intravenous administration to human subjects is presented. Using atomic absorption spectroscopy to determine total calcium, the specific activity of the urinary calcium 47 was found to be higher than that of the contemporary serum during the first 96 hr. Calculated renal clearance of calcium 47 was higher than that of calcium 40 during this time interval. Equilibrium dialysis of the serum resulted in a decrease in its calcium 47 specific activity, an effect which was enhanced by increasing the volume of dialyzing fluid. Fractions of serum collected from a Sephadex column contained unequal proportions of the two isotopes. The nonultrafiltrable calcium fractions appear to be heterogenous, and of different dissociation characteristics. At least one is not readily exchangeable with the diffusible calcium. renal clearance of calcium isotopes; metabolism of radiocalcium 47; distribution of calcium 47 in blood serum fractions; dialyzable serum calcium 47; serum calcium 47 specific activity; urine calcium 47 specific activity; nondialyzable serum calcium 47; calcium in Sephadex serum fractions Submitted on July 24, 1964
Relations between sweating, cutaneous blood flow, and body temperature in work
Authors: Robinson S. , Meyer F. R. , Newton J. L. , Ts'Ao C. H. , Holgersen L. O. 
Published: December 2017

Men worked on a treadmill for periods of 5, 5, 10, 10, 10 and 10 min, stopping for 2 min between work periods to be weighed. Finger and mean skin temperatures decreased at the beginning of work (10 mets). When room temperature was 25 C vasodilation occurred in the finger in the third work period as gastrocnemius muscle and femoral vein temperatures reached maximal values. Temperatures of skin and saphenous vein blood rose rapidly as the men reclined during the rest periods and decreased when work was resumed, coinciding with changes of femoral temperature in the opposite directions. These rapid shifts in temperature indicate that during the rest periods the proportion of blood coming from the skin into the trunk of the femoral was greater than during the work periods. The onset of sweating, the rate of its increase in the early stages of these work experiments, and its decline in recovery more nearly paralleled corresponding changes in femoral temperature than any of the other temperatures measured. exercise; femoral vein temperature; temperature regulation; saphenous vein temperature; skin temperature Submitted on October 5, 1964
Body composition and atherosclerosis in cocks after long exposure to heat and cold
Authors: Fisher Hans , Griminger Paul , Weiss H. S. 
Published: December 2017

Three groups of adult cocks were exposed respectively to 2, 21, and 32 C temperatures for a 15-month experimental period. Food consumption, body weight, body composition, feather composition and weight, atherosclerosis and fatty acid composition of plasma, liver and depot fat were studied. It was found that with the use of a pelleted diet the cold-exposed cocks maintained the same body weight as the control group (21 C). The heat-exposed birds were lighter in weight than either controls or cold-exposed and had significantly less body fat and water. Severity of atherosclerosis was not affected in the cold-exposed cocks, despite greatly increased caloric intake. The liver fat of the cold-exposed cocks was significantly higher in di- and hexaenoic acids than that of the controls or heat-exposed birds. The depot fat of heat-exposed birds was lower in monoenoic and higher in dienoic acid than that of controls or cold-exposed birds. The cold-exposed cocks also had significantly more feathers and feather lipid than the other two groups. fatty acid composition; depot fat temperature; feathers Submitted on November 23, 1964
Simultaneous uptake of N2O and cyclopropane in man as a test of compartment model
Authors: Rackow Herbert , Salanitre Ernest , Epstein Robert M. , Wolf Gerald L. , Perl William 
Published: December 2017

An experiment involving simultaneous pulmonary uptake of nitrous oxide and cyclopropane is analyzed for compatibility with the perfusion-limited multicompartment model of inert gas uptake. These test gases have approximately equal solubilities in body watery tissues (blood, muscle, viscera, etc.) but an approximately 1-to-8 ratio of solubility in fat. Therefore, the measured difference in time course of pulmonary uptake provides a sensitive test of the mechanism of adipose tissue uptake of these gases. The experimental data could not be accounted for by the model, assuming plausible compartment parameters, or by using derived compartment parameters. Expansions of the model to account for the discrepancy are suggested. gas uptake in body; fat-soluble gas uptake; multiple gas uptake; fat perfusion; adipose tissue perfusion; blood flow to fat; perfusion of fat; inert gas kinetics; tissue gas exchanges Submitted on February 3, 1964
Effects of unilateral thoracic irradiation on lung function
Authors: Teates Charles D. 
Published: December 2017

Five dogs were irradiated in one hemithorax with 4,500 R midlung dose over 23 —27 days. Function of each lung was studied prior to irradiation and at frequent intervals up to 207 days after irradiation. A nonspecific reduction in function of the irradiated lung was reflected on all indices. The reduction in diffusion capacity apparently resulted from factors other than alveolar-capillary block. Pulmonary function did not improve during the period studied. Pathologic, radiologic, and physiologic studies showed considerable variation of damage from one animal to another and within the same lung, but each subject showed change of some degree. X-irradiation; lung pathology Submitted on October 2, 1964
Left ventricle myocardial temperatures in the intact dog
Authors: Afonso Skoda , O'Brien George S. , McKenna David H. , Jaramillo Cesar V. , Rowe George G. 
Published: December 2017

Gradients between left ventricle myocardial temperatures and that of the left ventricle blood were measured by transthoracic route in the intact dog. Results revealed that myocardial temperature is not uniform. Higher gradients were found in the basal portion of the interventricular septum and the papillary muscles and lower ones in the apical region. These differences are thought to be related to the thickness of myocardium as well as the relation between metabolic activity and vascularity of the sites where the temperatures were measured. temperature gradients, left ventricle; myocardium, temperature gradients; heart-blood/myocardium temperature gradients; papillary muscle temperature Submitted on July 17, 1964
Instantaneous blood flow in the human aorta
Authors: Snell Robert E. , Clements James M. , Patel Dali J. , Fry Donald L. , Luchsinger Peter C. 
Published: December 2017

The computed pressure-gradient technique has been applied to the measurement of instantaneous aortic blood flow in 15 male subjects. The mean values of those curves obtained in the ascending aorta were compared with simultaneous measurements made by the dye-dilution technique. The correlation coefficient between the two methods was 0.85 and the slope of the regression line 0.80. The ability to measure flow by the pressure-gradient technique depends mainly on the accuracy of the catheter-manometer system, radius measurement, and the estimation of “zero flow.” pressure-gradient technique; methods of blood flow measurement Submitted on June 22, 1964
Responses of oxygen electrodes to variables in construction, assembly, and use
Authors: Carey Francis G. , Teal John M. 
Published: December 2017

Oxygen electrodes were tested for response to variables in construction, assembly, and use. The half-wave potential was found to be inversely proportional to the KOH concentration used in assembling the electrode. The half-wave potential was moved to higher voltages by the use of thin membranes and by the use of Teflon rather than polyethylene membranes. This potential was not affected by cathode size, aging of the electrode, temperature, or replacement by carbonate of the hydroxide behind the membrane. Stirring effects can be reduced by low temperature, thick membranes, and small cathodes. Response time is the same for polyethylene and Teflon membranes and is proportional to the square of membrane thickness. Electrode blank, stability, and zero oxygen error are all discussed. The use of Teflon membranes, 1 n KOH as electrolyte, and 1.1-v polarization voltage is recommended. voltage plateau; Teflon membrane; respirometry; polarographic oxygen eletrode Submitted on September 14, 1964
Respiration and cerebrospinal fluid pH in metabolic acidosis and alkalosis
Authors: Mitchell R. A. , Singer M. M. 
Published: December 2017

An acute base deficit of 5 mm/liter (metabolic acidosis) was induced in one normal man by an initial oral dose of 20 g NH4Cl and sustained for 5 days by administering 3 g every 6 hr. pHa (arterial) decreased from 7.42 to 7.34 in 4 hr. Ve (minute ventilation) increased from 6.2 to 8.4 liters/min, PaCOCO2 decreased from 40 to 37 mm Hg, CSF pH increased from 7.32 to 7.34, and the CO2 response curve shifted –2.8 mm Hg Pco2 without slope change. At 24 hr, CSF pH was 7.32, with CSF Pco2 and HCO3 – reduced to 42 mm Hg and 21.0 mEq/liter, respectively (control 49 mm Hg, 24 mEq/liter). Ve increased to 9.8 liters/min, arterial pH increased to 7.37, PaCOCO2 fell to 36 mm Hg, and the CO2 response curve was –5.0 mm Hg from control. After 6 days of acidosis, acute increase in pHa to 7.45 in 2 hr by NaHCO3 ingestion decreased Ve to 6.8 liters/min, increased PaCOCO2 to 39 mm Hg, decreased CSF pH to 7.30, and shifted the CO2 response curve back to control. Results of this study are consistent with the hypothesis that the peripheral chemoreceptors initiate and sustain alterations in Ve in metabolic abnormalities in the following manner: 1) acute acidosis increases Ve by stimulating the peripheral chemoreceptors; 2) the PaCOCO2 falls and CSF pH increases, decreasing medullary (H+) chemoreceptor activity; and 3) active transport across the blood-CSF barrier restores CSF pH and the medullary (H+) chemoreceptor activity to normal, causing a further increase in ventilation that partially compensates for the metabolic acidosis. medullary respiratory chemoreceptors; peripheral chemoreceptors; blood-brain barrier; active transport Submitted on July 27, 1964