bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of increased intra-abdominal pressure on various circulatory parameters of the anesthetized dog
Authors: Jach E. T. , Marotta S. F. , Marbarger J. P.
Published: December 2017

Abdominal pressure of anesthetized dogs was elevated by the introduction of 18.5 mm Hg compressed air through a cannula tied securely into the peritoneal cavity. Significant decreases in circulating plasma volume (T-1824) were observed during the first 80 minutes of elevated pressure. Thereafter, plasma volume returned toward the control level except for a marked drop when the pressure was released. Hematocrit levels and plasma protein concentrations also indicated a loss of fluid. Mean vena cava pressure at the level of the heart did not markedly change, although the venous pressure below the diaphragm increased significantly. Arterial pressures decreased immediately upon elevation of the abdominal pressure, but returned to pre-experimental levels prior to release of elevated abdominal pressure. Concomitant with these circulatory alterations was a decrease in urine volume as well as a slight increase in serum potassium. Serum sodium remained essentially unaltered. These observations are compared to similar circulatory changes which occur during positive pressure breathing.

Submitted on April 27, 1959
Electrical-mechanical relationships in experimentally produced bundle-branch block and complete heart block
Authors: Samet Philip , Litwak Robert S. , Bernstein William H. , Kenyon Norman
Published: December 2017

Right and left ventricular pressure curves were recorded simultaneously with the electrocardiogram in the dog. Control observations were made during sinus tachycardia with normal intraventricular conduction, and repeated after production of right and left bundle-branch block and after production of complete heart block with idioventricular rhythm. The mode relationship between onset of isometric contraction in the two ventricles was 0.00 seconds during sinus tachycardia. During right bundle-branch block, left ventricular contraction started 0.01 second prior to the right; during left bundle-branch block, right ventricular contraction started 0.02 second prior to the left. During left ventricular idioventricular rhythm, left ventricular isometric contraction started 0.01 second prior to the right; during right ventricular idioventricular rhythm, right ventricular contraction started 0.01 second prior to the left. These changes in relative onset of ventricular contraction are far less than those expected on theoretical grounds.

Submitted on March 26, 1959
Polarographic studies of skin oxygen tension following sympathetic denervation
Authors: Davis Martin T. , Greene Nicholas M.
Published: December 2017

Using an open-tipped platinum electrode in the skin of the lower extremities of normal subjects, it was found that preganglionic sympathetic denervation resulted in a decrease in skin oxygen tension. This, in the presence of cutaneous hyperemia, indicates a decrease in capillary blood flow during the period of denervation.

Submitted on March 5, 1959
Total and partial gas tensions of human bladder urine
Authors: Hong Suk Ki , Boylan John W. , Tannenberg Alf M. , Rahn Hermann
Published: December 2017

The total and partial gas tensions of human bladder urine were studied by a modified Krogh micromanometric method combined with fractional absorption analysis and the use of a Clark oxygen electrode. Consumption of O2 by reducing substances in urine was determined and correlated with its specific gravity and pH. Oxygen tension of bladder urine averages 50 mm Hg during air breathing and 58 mm Hg during pure O2 breathing. Pco2 ranges from 47 to 152 mm Hg and correlates best with urinary pH. The average figure for urine nitrogen tension, 550 mm Hg, agrees closely with the calculated Pn2 of alveolar air. Total gas tension of urine is typically about 60 mm Hg less than atmospheric and changes in total gas tension are shown to reflect changes in Pco2, the tensions of the other gases remaining relatively constant in an experimental period. The physiological significance of these total and partial gas tensions is discussed. A counter-current gas diffusion system is proposed to account for the difference between the oxygen tension of urine and renal venous blood.

Submitted on September 24, 1959
Finger numbness after acute local exposure to cold
Authors: Morton Rosemary , Provins K. A.
Published: December 2017

Twenty subjects exposed the index finger to air at –22°C and a wind speed of 300 ft/min. until the indicated skin temperature fell to –5°C. The finger was then returned to room temperature conditions (19°C) and the subject tested on each of two tasks involving tactile discrimination until the finger had fully recovered. The degree of impairment on both sensori-motor tasks at a given skin temperature varied appreciably from subject to subject, although most subjects showed little impairment above about 8°C. The evidence suggests that while finger numbness as measured by Mackworth's V-test may indicate a corresponding impairment of performance in accuracy of pressure reproduction, testing subjects on either task at normal skin temperature will have little predictive value for their relative performance after cold exposure in the present situation.

Submitted on December 24, 1958
Effects of oxygen inhalation on cold pressor responses of man
Authors: MacCanon D. M.
Published: December 2017

The effects of oxygen inhalation on blood pressure and pulse rate responses to the cold pressor test were determined in 10 subjects. The results showed that under basal conditions diastolic pressures and pulse rates were significantly (P < 0.001) reduced by oxygen breathing. However, greater increases in systolic (P = 0.05) and diastolic (P < 0.01) pressures and pulse rates (P < 0.01) attended cold stimulation when oxygen was inhaled. One minute after removal of the cold bath, systolic and diastolic pressures remained significantly (P = 0.02, <0.001, respectively) further from basal levels during O2 experiments, although pulse rates had reached control values.

Submitted on August 20, 1959
Effect of high and low humidity on heat exchanges of lightly clothed men
Authors: Iampietro P. F. , Buskirk E. R.
Published: December 2017

Six healthy young men were exposed, lightly clothed, to various combinations of wind (<1 and 10 mph), temperature (40° and 50°F) and relative humidity (30 and 100%). Skin and rectal temperatures and oxygen consumption were recorded. The results show that relative humidity had no effect on the physiological responses measured, whereas wind and dry bulb temperature had marked effects. This follows the pattern seen when men were exposed without clothing and indicates that, under chamber conditions, there is little interaction between clothing and humidity that could account for cold-wet ‘chill.’ The importance of considering radiation in any comparison of cold-wet and cold-dry environments is discussed.

Note:

(With the Technical Assistance of J. A. Vaughan)

Submitted on August 19, 195
Breath holding during and after muscular exercise
Authors: Åstrand Per-Olof
Published: December 2017

Breath holding was performed a) at rest, b) at the beginning of muscular work, c) during the steady state of work and d) immediately after work. End-expiratory air was analyzed for CO2 and O2 tensions. At breaking point the PaCOCO2 values were similar in a) and b) (below 52 mm Hg with air breathing) and in c) and d, respectively. The higher the work load the higher the PaCOCO2 in c) and d) (above 70 mm Hg at heavy work load breathing air; after O2 breathing above 90 mm Hg). The PaOO2 values obtained were lower during and after work than at rest. These events and the increased ‘tolerance’ for high CO2 and low O2 in breath holding during and immediately after exercise are discussed in light of the theory that proprioreceptive impulses from working limbs are important in the control of respiration during exercise.

Submitted on October 2, 1959
Hypoxemia due to venous admixture in cirrhosis of the liver
Authors: Williams M. Henry
Published: December 2017

The percentage of venous admixture to arterialized blood was measured by two different techniques in two groups of patients with cirrhosis of the liver and, in both groups, averaged 9.7% of the cardiac output. Since one of the techniques was based on measurement of the arterial oxygen tension during oxygen breathing, the venous admixture must have resulted from some type of right-to-left shunt. It was not possible to determine whether the right-to-left shunt resulted from anastamoses between the portal system and the bronchopulmonary venous system or from pulmonary arteriovenous communications.

Submitted on March 30, 1959
Respiratory dead space and arterial to end-tidal CO2 tension difference in anesthetized man
Authors: Nunn J. F. , Hill D. W.
Published: December 2017

Observations were made during both spontaneous and artificial respiration on 12 fit patients anesthetized for routine surgical procedures. Above a tidal volume of 350 ml (BTPS), the anatomical dead space was close to the predicted normal value for the subject. Below 350 ml, it was reduced in proportion to the tidal volume. The physiological dead space (below the carina) approximated to 0.3 times the tidal volume for tidal volumes between 163 and 652 ml (BTPS). Throughout the range the physiological dead space was considerably in excess of the anatomical dead space measured simultaneously. The difference (alveolar dead space) varied from 15 to 231 ml, being roughly proportional to the tidal volume. The mean arterial to end-tidal CO2 tension difference was 4.6 (S.D. ±2.5) mm Hg and not related to tidal volume or arterial CO2 tension. None of the findings appeared to depend on whether the respiration was spontaneous or artificial.

Submitted on September 25, 1959
Carbon monoxide diffusing capacity in normal male subjects, age 20–60, during exercise
Authors: Hanson John S. , Tabakin Burton S.
Published: December 2017

The pulmonary diffusing capacity for carbon monoxide has been determined during steady-state treadmill exercise in 100 normal males, age 20–60 years. The method described provides a simple and acceptable technique for determination of diffusing capacity, obviating the need for arterial blood. Mean normal values and limits of normal have been established for the various age groups. Results agree closely with less extensive studies in the literature. The normal range for the Dco is seen to be quite wide, and the clinical value of the determination as a screening test is questioned.

Submitted on July 6, 1959
Sweat iodide excretion in patients with cystic fibrosis of the pancreas
Authors: Brodkey J. S. , Gibbs G. E.
Published: December 2017

Thirteen children with cystic fibrosis of the pancreas and fourteen normal children were studied. After preliminary saturation of the thyroid with Lugol's solution, a tracer dose of I131 was administered. Sweating was encouraged with wool blankets and heating pads. The sweat was collected on gauze pads which were then centrifuged to provide the free fluid. Sweat chloride was determined as were the number of disintegrations per minute in 1 cc of both sweat and serum. It was reconfirmed that fibrocystics excrete more chloride in their sweat than do normals. It was further found that fibrocystics excrete more iodide in their sweat than do normals.

Submitted on September 29, 1959
Lung volumes at different depths of submersion
Authors: Hong S. K. , Ting E. Y. , Rahn H.
Published: December 2017

Vital capacity and expiratory reserve volumes of the lung were measured in seven subjects in the supine position. These were reduced when subjects were submersed at depths of 10, 20, 30 and 40 cm below the surface while breathing through rigid tubes. The reduction in these lung volumes is similar to that observed when subjects are subjected to continuous negative pulmonary pressure. The equivalence of pressurization of the thorax by air and water is discussed. When man in the supine position is just submersed the resting lung volume changes are equal to that when a negative pulmonary pressure of 6 cm H2O is applied.

Submitted on February 8, 1960
Cardiovascular responses of man during negative-pressure breathing
Authors: Ting E. Y. , Hong S. K. , Rahn H.
Published: December 2017

Blood pressures, heart rate and finger volumes were recorded while supine subjects submitted to various degrees of continuous negative-pressure breathing. The lowest pressure was –30 cm H2O. Systolic and diastolic arterial pressures as well as heart rate remained essentially unchanged. The peripheral venous pressure estimated by an indirect method was slightly lowered. Finger plethysmography indicated a peripheral vasoconstriction to the same degree as observed during positive-pressure breathing. Various considerations suggest that during negative-pressure breathing the veins entering the thoracic cavity collapse and effectively divide the circulation into the thoracic one which operates at a considerably reduced pressure, and the nonthoracic circulation which is maintained at normal pressures. The pressure difference between these two circulations is maintained by the left ventricle.

Submitted on February 8, 1960
Metabolism and temperature of Arctic Indian men during a cold night
Authors: Irving Laurence , Andersen Kristian Lange , Bolstad Atle , Elsner Robert , Hildes J. A. , L⊘yning Yngve , Nelms John D. , Peyton Leonard J. , Whaley Robert D.
Published: December 2017

During 7 hours of comfortably warm sleep, average metabolic rates of 11 Indian and 7 white men were alike. Since the Indians were 15% lighter their metabolic rates (MR's) referred to weight were greater. During a night at 0° with insufficient covering, MR's rose to 129% and 132% in the two groups. Cold caused equal myographic records of shivering (15% and 13% of records) and gross muscular movement appeared in 6.5% of the records for each group. Encephalograms showed that Indians slept more (51%) than whites (31%). Shivering was recorded in Indians and white men during encephalographic indications of sleep. Rectal temperatures of Indians declined about 0.5°. During cold nights skin on the bodies of all subjects cooled 3°–5° and about 15° on the feet. All subjects were disagreeably cold, but their cold sensations stimulated metabolic heat production only half as much as would be necessary to maintain fairly comfortable warmth.

Submitted on August 3, 1959
Effect of salicylates on ventilatory response to inhaled carbon dioxide in normal subjects
Authors: Samet Philip , Fierer Eugene M. , Bernstein William H.
Published: December 2017

The basic purpose of this investigation was to determine whether salicylates increase the sensitivity of the respiratory center to inhaled CO2. The problem was approached by noting the effect of salicylates upon ventilation and arterial blood Co2 tension and pH during inhalation of compressed air and 3% and 5% Co2 in air. These studies were performed in 30 subjects, 15 of whom ingested 2.1 gm salicylate; the other 15 ingested 3.6 gm. The results demonstrate that the ventilatory response to CO2 was increased only by the larger dose of salicylate. Variations in dead-space volume secondary to increments in tidal volume were observed. Dead-space volume increased in approximately linear fashion with increase in tidal volume.

Submitted on October 28, 1959
Some chemical, physical and biologic characteristics of dyes used to visualize lymphatics
Authors: Threefoot Sam A.
Published: December 2017

Characteristics of dyes used to study lymphatics and other biologic systems can be of significance in quantification and interpretation of data. For example, determination of concentration is influenced by changes in spectral characteristics of solutions of Patent Blue V (PBV), T-1824 or Direct Sky Blue (DSB) produced by changes in pH. Interpretation of biologic data must consider the 50% binding of PBV and the almost 100% binding of T-1824 and DSB demonstrated by protein precipitation studies. This was confirmed for PBV by dialysis, but not for T-1824 or DSB because they adhered to the viscose bag as they did to the filter paper during attempts at electrophoresis. PBV moved independently of protein on electrophoresis, suggesting a weak linkage. After intradermal injection, all three dyes first visualized, then diffused from lymphatics. Only PBV appeared in urine in measurable quantities, approximately 10% being recovered in urine before it was too dilute to measure in 24 hours. One-half that excreted was recovered in the first 2½ hours.

Submitted on January 25, 1960
Physiological behavior of I131-labeled compounds for the study of cardiac output
Authors: Homer George M. , Zipf Robert E. , Hieber Thomas E. , Katchman Bernard J.
Published: December 2017

Radioiodinated diiodo-p-aminohippuric acid (DI131PAH) and N-(2,4-diiodo-3-hydroxyphenyl) urea (DI131HPU) were synthesized and examined for their potential usefulness in measuring the cardiac output in animals. These labeled compounds were injected intravenously into rats, rabbits and 13 dogs for study. The average rate of disappearance of DI131PAH from the blood stream of dogs was 50% and 90% in 1.0 and 6.9 minutes, respectively. Only a very small percentage of the injected radioactivity localized in the tissues, with approximately 0.5% in the thyroid at 24 hours. Under appropriate conditions of the experiment, more than 90% of the injected radioactivity was recovered in the excreta. Cardiac output values determined with DI131PAH on dogs were reproducible and in the range of reported values determined with other materials.

Submitted on January 25, 1960
Measurement of human capacity for aerobic muscular work
Authors: Billings Charles E. , Tomashefski Joseph F. , Carter Earl T. , Ashe William F.
Published: December 2017

In an effort to define a simple, precise measure of cardiovascular response to exercise, a test devised by Bruno Balke was studied. The test involves walking at constant speed on a treadmill, the slope of which is periodically increased, while heart rate is measured accurately each minute. Balke had noted that physiologic alterations indicative of impending exhaustion occurred at or near the time the heart rate reached 180/min.; he used the time at which the rate was attained as an end point. Our studies suggested that a single temporal measurement was insufficiently sensitive as an estimate of cardiovascular response to the procedure. Another scoring method was derived, involving the integration of heart rates with respect to time. A strong positive correlation was found between the described score and the work done during each of 133 test runs. Additionally, evidence was obtained which suggests that it may not be necessary to force subjects to an end point near exhaustion in order to estimate their ability to tolerate exercise of this type.

Submitted on March 14, 1960
Electromyography of the diaphragm in man and transdiaphragmatic pressure
Authors: Agostoni E. , Sant'Ambrogio G. , Carrasco H. del Portillo
Published: December 2017

The electrical activity of the vertebral part of the diaphragm in man has been studied in physiological conditions through an esophageal bipolar lead; the spirogram and/or the intrathoracic and gastric pressure were simultaneously recorded. Electrical activity has been found during inspiration; it is approximately related to the transdiaphragmatic pressure as the activity found during graded inspiratory efforts at relaxation volume. At minimum lung volume the electrical activity during maximum inspiratory efforts is small notwithstanding the high transdiaphragmatic pressure. Electrical activity may persist at the beginning of expiration, showing that the diaphragm does not relax completely at the onset of expiration. At the end of maximum expiration a small electrical activity may appear, the transdiaphragmatic pressure is high and it is not clear to what extent the diaphragm is passively distended or contracted. At relaxation volume during expiratory efforts electrical activity appears only when the effort is high, while during expulsive efforts, even moderate, the activity is marked.

Submitted on May 2, 1960
Role of the diaphragm in breathing in conscious normal man: an electromyographic study
Authors: Petit J. M. , Milic-Emili G. , Delhez L.
Published: December 2017

The electrical activity of the diaphragm was detected by means of electrodes placed, via the esophagus, at the level of the diaphragmatic esophageal orifice. This activity was synchronous with the respiratory variations of transdiaphragmatic pressure. The activity of the diaphragm, which occurred during inspiration and continued into expiration for a varying length of time, affected the shape of the pressure-volume diagrams of breathing cycles and of the expiratory flow curves. The relative importance of the antagonistic activity of inspiratory muscles opposing the expiratory elastic forces decreased with increasing ventilation. The implications of the antagonistic activity of the diaphragm on the mechanical efficiency of breathing are discussed.

Submitted on April 11, 1960
Respiratory adaptation to hyperthyroidism
Authors: Valtin H. , Tenney S. M.
Published: December 2017

In order to test the general postulate that increases in whole body metabolism are accompanied by net respiratory stimulation, respiratory adaptation to thyrotoxicosis was studied in clinical hyperthyroidism and in experimental hyperthyroidism in man and the rat. It was found that in contrast to other hypermetabolic states such as fever and salicylate and dinitrophenol administration, alveolar CO2 tension rises in hyperthyroidism, reflecting a proportionately greater increase in metabolism (CO2 production) than in alveolar ventilation. Ventilatory response curves in three human subjects with experimentally induced hyperthyroidism showed no increase in sensitivity (Deltaa/DeltaPaCOCO2 of the respiratory center to CO2. This finding differs from that in salicylism and dinitrophenol administration in which enhanced sensitivity is manifest. It is concluded that the respiratory stimulation resulting from increased CO2 production is modified by factors such as changes in respiratory center sensitivity, changes in cerebral blood flow and direct stimulation of the respiratory center, so that the net respiratory adjustment cannot be predicted from a knowledge of the increase in metabolism alone.

Submitted on April 7, 1960
Influence of red cell membrane on diffusion of oxygen
Authors: Kreuzer F. , Yahr W. Z.
Published: December 2017

Experiments in vitro were conducted on human blood at 37°C. Centrifuged blood samples were divided into packed red cells and three kinds of hemoglobin solution of equal concentration with the hemolysis effected by freezing and thawing, distilled water and ether. Since the four media had the same hemoglobin concentration, the conditions for the propagation of oxygen were substantially identical, with the only difference that the oxygen had to cross the barrier of the red cell membranes in the case of the cells. All media were analyzed with the thin-layer technique. Light transmission changes resulting from the uptake of pure oxygen by the reduced media were continuously recorded. From such tracings, the one-third and one-half saturation times were evaluated and compared. No significant difference was found between any of the highly concentrated hemoglobin solutions and the packed red cell suspensions. It was concluded that the red cell membrane does not seem to represent an essential impediment to the propagation of oxygen under these circumstances.

Submitted on April 20, 1960
Interactions of increased pO2 and pCO2 effects in producing convulsions and death in mice
Authors: Marshall John R. , Lambertsen Christian J.
Published: December 2017

In 379 mice subjected to from 1 to 11 atm. of pO2 and 0 to 304 mm Hg of pCO2 for 90 minutes, oxygen was convulsigenic at pressures greater than 3 atm. and lethal at greater than 4 atm. Carbon dioxide in 1 atm. of O2 was not convulsigenic but was lethal at very high tensions. In the presence of O2 at high pressure (OHP) small elevations of CO2 tension shortened the preconvulsive latent period, whereas CO2 tensions greater than 120 mm Hg inhibited convulsions. Survival time in OHP was shortened by the addition of CO2. An interaction between OHP and CO2 effects is suggested by both the preconvulsive latent period and survival time data. The effects of CO2 on OHP and electroshock convulsions are compared and possible reasons for differences are discussed in light of the previously demonstrated general cortical depression and inhibition of convulsions by CO2. The potentiation of OHP convulsions by low CO2 tensions is probably due to effects on brain blood flow. Although death can occur without convulsions there is a tendency for animals susceptible to convulsions to be also susceptible to the lethal properties of OHP with CO2.

Submitted on July 28, 1960
Association of an inhibitor with deficiency of plasma-clearing activity
Authors: Koppel J. L. , Novak Lillian V. , Olwin John H.
Published: December 2017

Citrated human plasmas obtained from patients without prior injection of heparin were studied for their lipemia-clearing activity (LCA) in the presence of partially purified human clearing-factor preparations. LCA was determined by measuring the change in optical density of a clearing system consisting of the plasma to be studied and a standard fat emulsion. Under these conditions, reduced or totally lacking plasma-clearing activity, presumably due to plasma-cofactor deficiency, could be largely and, often, completely restored by any one of the following procedures: a) addition to plasma of Na-citrate, Na-oxalate or Na-Versenate; b) addition to it of heparin, manuronate, polyethylene sulfonate or G-31150/III; c) addition of certain sulfhydryl inhibitors; d) adsorption of plasma with barium sulfate; and e) its preincubation with purified human plasmin. The results indicate that excessive inhibitor levels in plasma rather than a lack of cofactor may be responsible for clearing deficiency.

Submitted on August 4, 1960
Effect of lung inflation on static pressure-volume characteristics of pulmonary vessels
Authors: Permutt Solbert , Howell J. B. L. , Proctor D. F. , Riley R. L.
Published: December 2017

It was shown that in excised lungs of dogs the effect of changing the degree of inflation of the lung was to change the static volume-pressure curve of the pulmonary vascular bed in shape, slope, and position. The data show that there is no simple answer to the question: does the pulmonary vascular bed get bigger or smaller with inflation of the lung? If vascular pressure was held constant when transpulmonary pressure was changed from 0 to 30 cm H2O, vascular volume increased when vascular pressure was low and decreased when vascular pressure was high. In addition, when vascular pressure was held constant, vascular volume changed in an opposite way depending on whether transpulmonary pressure was changed from low to moderate values or from moderate to high values.

Submitted on June 9, 1960
Pulmonary vascular resistance as determined by lung inflation and vascular pressures
Authors: Roos Albert , Thomas Lewis J. , Nagel Eugene L. , Prommas Don C.
Published: December 2017

A controlled study of the effects of pulmonary arterial, left auricular, pleural and intrapulmonary pressures on pulmonary vascular resistance in live dogs was carried out. More than 350 pressure-flow curves were obtained from 10 dogs, using a vertical tube apparatus for perfusion of the left lung with the dog's own blood. The data obtained permit quantitation of the changes in resistance resulting from changes in each of the four pressure parameters. In general, pulmonary vascular resistance fell in response to elevation of either pulmonary arterial or left auricular pressures. Positive pressure inflation invariably produced a considerable rise in resistance, but negative pressure inflation resulted in only a slight fall, followed by a small resistance rise on further inflation. A quantitative integration of the data was made to analyze the effects on pulmonary vascular resistance of spontaneous breathing and positive-pressure inflation with the chest closed. This shows, for example, that the net effect on resistance of even a deep spontaneous inspiration would be small, yet flow would increase considerably.

Submitted on March 7, 1960
Effect of prednisone on digital vascular reactivity in normotensive and hypertensive subjects
Authors: Mendlowitz Milton , Naftchi Nosrat , Weinreb Herbert L. , Gitlow Stanley E.
Published: December 2017

Reactivity to L-norepinephrine (NE) was studied in the digital circulation of normotensive and hypertensive subjects before and after the administration of glucocorticosteroids. After 1 week of oral prednisone administration (30 mg daily) NE reactivity was higher in some, but not all, the normotensive subjects and remained substantially unchanged in the hypertensive group. A single intravenous injection of prednisolone (100 mg) resulted in a moderate increase in NE reactivity in the normotensive but not in the hypertensive subjects. After 3 weeks of oral prednisone administration (30 mg daily), NE reactivity was doubled or trebled in most normotensive subjects but remained unchanged in the patients with essential hypertension. These observations suggest that the effect of glucocorticosteroids on NE reactivity in normotensive subjects is chemical and that this effect is absent or modified in patients with essential hypertension.

Submitted on December 28, 1959
Tissue water and electrolytes in an isolated perfused rat's heart preparation
Authors: Taylor I. M. , Huffines W. D. , Young D. T.
Published: December 2017

An apparatus and technique for perfusion of rats' hearts is described. At 27°C hearts beat spontaneously, and the preparation is stable for periods in excess of 12 hours as judged by heart rate, EKG configuration, force of contraction, pH of perfusion medium and intracellular potassium. Carbon-14 labeled sucrose has been compared with chloride as a measure of tissue extracellular space and has been found unsatisfactory because volume of distribution for carbon-14 is larger than for chloride in most experiments. Carbon-14 labeled inulin-carboxylic acid (ICA), in contrast, appears to be a satisfactory marker for extracellular space. Distribution of ICA is complete in 1 hour. Values for intracellular electrolytes and water, derived assuming extracellularity of ICA, are: water, 2.56 α 0.14 gm/gm dry tissue; Na+ 24.36 α 14.12 mEq/kg cell water or 6.18 α 3.53 mEq/100 gm dry tissue; Cl- 23.16 α 6.70 mEq/kg cell water or 5.96 α 1.93 mEq/100 gm dry tissue; and K+ 144.69 α 7.31 mEq/kg cell water or 36.99 α 1.55 mEq/100 gm dry tissue. Chloride is not a satisfactory measure of extracellular space in the isolated perfused rat heart.

Submitted on July 20, 1960
Body cooling and response to heat
Authors: Veghte J. H. , Webb Paul
Published: December 2017

Prior body cooling with cold air or water immersion increased human tolerance to a high level of heat stress. The lower the body temperature at the onset of the heat exposure, the greater the increase in tolerance times over the control values. Mean body temperature was the only discriminating criterion which successfully correlated with tolerance time in these experiments. Sudomotor activity in heat was inhibited by prior body cooling. It is postulated that the onset of sweating is due to a gradient effect, not to either peripheral or central control.

Submitted on October 5, 1960
High-frequency atrial electrical activity
Authors: Caceres Cesar A. , Kelser George A. , Calatayud Juan
Published: December 2017

Left and right atrial intracavitary and conventional surface leads were used to study electrocardiographic activity during the PR interval. Electronic filters were employed for analysis of wave frequency and harmonic content from 1.7 to 1700 cps. Amplifiers permitting standardization sensitivity to 500 mm/mv were used to obtain oscilloscopic tracings recorded at a paper speed of 75 mm/sec. Frequency analysis of the electrical potential recorded during P wave inscription demonstrated the presence of high-frequency content that is excluded by conventional electrocardiographic amplifiers. The high-frequency components are associated with the time of inscription of the electrocardiographic intrinsic deflection and have a relationship to the characteristics of the pressure-pulse curve. These relationships suggest that intracavitary high frequencies and the electrocardiographic intrinsic deflection originate from electrical discharges associated with initiation of contractile events.

Submitted on June 6, 1960
Utilization of body energy reserves during work in dogs
Authors: Young D. R. , Price R.
Published: December 2017

Excretion of urinary nitrogen and acetone at rest and during four controlled levels of work output (treadmill running) was examined in five postabsorptive dogs. With resting energy-expenditures of 600–800 Cal., the average outputs of nonprotein nitrogen, urea nitrogen, creatine nitrogen, and acetone were 2.19 gm, 1.69 gm, 74.7 mg, and 11.6 mg, respectively. With the possible exception of acetone, output of the various urinary constituents was significantly higher (4 x) at rest than during work of comparable cost. Energy metabolism during the performance of 300, 600, 1200, and 1800 Cal. of work was estimated from the respiratory gas exchange and urinary nitrogen. During long-sustained physical work, the percentage of energy derived from the oxidation of carbohydrate, fat, and protein was relatively constant at 65, 32, and 3%, respectively. Preliminary calculations suggest that all of the energy, whether combusted as carbohydrate or fat, was derived ultimately from the body lipids.

Submitted on October 26, 1960
Single-breath analysis of carbon dioxide concentration records
Authors: Berengo A. , Cutillo A.
Published: December 2017

A fourth-degree equation has been employed to describe the capnogram. By means of its derivative functions two flexion points can be determined, VeI and VeII, the former corresponding to the maximal increase in |FeCO2|, the latter to the minimal increase, i.e., to the beginning of the alveolar phase. The dead space exhaled can be expressed as a continuous function by an equation using the integral function of the empirical curve. The experimental curve (capnogram) has been divided into four phases: lag, where |FeCO2| = |FiCO2; transition, where |FeCO2| increases steadily; log, where |FeCO2| increases exponentially; and alveolar, where FaCO2 increases steadily again. The slope of the record is related to flow rate and total anatomical dead space in the transition phase, to FaCO2 in the log phase, to the physiological dead space and the distribution of inspired gas in the alveolar phase. In the lag phase the dead space arising from the upper airways is exhaled. In the transition phase before VeI the increase in |FeCO2| is almost constant; after VeI it becomes smaller, with formation of a dead-space tail or of a rather flame-shaped front. At the point VeII, the whole anatomical dead space is washed out, and air arising from the alveoli is exhaled, presumably uncontaminated with dead-space gas.

Submitted on October 12, 1960
Respiratory quotient during exercise
Authors: Issekutz B. , Rodahl K.
Published: December 2017

O2 uptake and CO2 output were determined during exercise on the bicycle ergometer. During moderate and heavy work three phases could be distinguished in the time course of RQ: a) initial increase, b) secondary drop followed by c) a continuous rise to a steady state which was reached after 3 ½12—4 min work. The rise of work RQ (ΔRQ) above an assumed metabolic RQ of 0.75 (or 0.83) showed an approximately logarithmic increase as work load increased. In the same subject there was a straight-line correlation between “nonmetabolic” excess CO2 (= total CO2 minus 0.75 x O2) and the increase of blood lactate level ( P < 0.001). In pooled calculations, a correlation coefficient γ = 0.92 was found. Whereas the respiratory minute volume plotted against O2 uptake or CO2 output showed a relative hyperventilation as the subject approached maximal aerobic capacity, excess CO2 increased with the ventilation in a straight-line fashion. It was concluded that the δRQ represents the percentual participation of anaerobic glycolysis in the total energy expenditure rather than the fuel used during exercise.

Submitted on January 26, 1961
Relation of plasma fibrinogen concentration changes to human arteriosclerosis
Authors: Pilgeram L. O.
Published: December 2017

A 35% increase (P < 0.001) in plasma fibrinogen levels was found in patients who recovered from the trauma of myocardial infarction and had not received anticoagulant therapy for 5 months preceding donation of plasma. The elevated fibrinogen levels are not a consequence of inflammatory conditions or traumatized tissue resulting from clinically overt vascular incidents. The fibrinogen level does not return to normal following a myocardial infarction. Occlusion of beta lipoproteins in the fibrin coagulum did not account for elevated levels of fibrinogen as shown by experiments where a) known quantities of alpha and beta lipoproteins were added to the test system, b) correction was made for the occlusion factor, and c) the increased yield due to this occlusion factor represented only a 3.5% increase in fibrinogen yield for as much as 300% increase in the level of beta lipoproteins. The fibrinogen level not only increases with age but also superimposes upon the arteriosclerotic an increase in addition to that occurring with increasing chronologic age. The role of fibrin in vascular hypertrophy and atheromatous development is emphasized. Possible causes for abnormal levels of fibrinogen are discussed.

Note:

(With the Technical Assistance of A. C. Schram and D. Mills)

Submitted on December 5, 1960
Acute effects of inhalation of cigarette smoke on airway conductance
Authors: Nadel Jay A. , Comroe Julius H.
Published: December 2017

We used the body plethysmograph to measure the ratio of airway conductance (reciprocal of airway resistance) to thoracic gas volume (TGV) in a group of healthy subjects, including 23 noncigarette smokers and 25 cigarette smokers. There was no significant difference between male and female smokers and male nonsmokers. Airway conductance/TGV was significantly higher in female nonsmokers. We studied the acute effect of inhalation of cigarette smoke on airway conductance/TGV in 36 healthy subjects (21 smokers and 15 “nonsmokers”) and 22 patients with cardiopulmonary disease (all smokers). The ratio decreased after the inhalation of cigarette smoke in both groups. The effects were almost immediate; the mean duration of effect was 35 min. Inhalation of 0.5% isoproterenol aerosol reversed or prevented the effect of inhalation of cigarette smoke. The decrease in conductance/TGV caused by inhalation of cigarette smoke did not appear to be related to inhalation of nicotine or of other volatile substances.

Submitted on January 23, 1961
A microelectrode for determination of dissolved oxygen in tissue
Authors: Charlton G.
Published: December 2017

This microelectrode, which, in principle, resembles the Clark polyethylene membrane electrode, may be used for the measurement of O2 tension in biological fluids. It is unaffected by the presence of fats, proteins, or hydrated ions in the external fluid and possesses the following characteristics: external diameter, 0.75 mm, O2 tension to current relationship linear over a range of Po2 0—702 mm Hg; accuracy ±0.5% at 150 mm Hg; stability over several hours ±0.5%; response time to 99% at 37 C is 2 min; temperature/current relationship, linear or curvilinear; temperature equilibrium, 1 min; movement/current relationship, logarithmic; approximate maximum effect of movement, 4%. The application of membrane electrodes to the measurement of O2 within tissues is discussed. The electrodes may also be used to measure the resistance of tissues to dissolved O2 transport. The concept of “relative available oxygen” is introduced.

Submitted on December 9, 1960
Steady-state temperature distribution in man
Authors: Wissler Eugene H.
Published: December 2017

A steady-state, mathematical model for the human heat transfer system has been developed. This model includes the following factors: a) the distribution of metabolic heat generation, b) conduction of heat in tissue, c) convection of heat by flowing blood, d) loss of heat by radiation, convection and evaporation at the surface, e) loss of heat through the respiratory tract, and f), countercurrent heat exchange between large arteries and veins. Computed results were compared with experimental results for the nude basal man and found to be satisfactory.

Submitted on August 1, 1960
Steady state carbon monoxide diffusing capacity in normal females
Authors: Hanson John S. , Tabakin Burton S.
Published: December 2017

The diffusing capacity of the lung for carbon monoxide was determined in 100 normal females age 20—60 years during steady state treadmill exercise. Values obtained were compared with a corresponding study in males, and it was established that when body surface area is taken into account there is no significant sex difference in DlCO. No significant decrease in diffusing capacity was seen with advancing age. Normal mean values and limits of normal for the various age groups are given.

Submitted on February 8, 1961
Cardiovascular response to acute heat stress
Authors: Koroxenidis Gabriel T. , Shepherd John T. , Marshall Robert J.
Published: December 2017

Cardiac output was measured simultaneously with blood flow in hand and forearm in eight healthy subjects before and during body heating. The heating was carried out by immersing the feet and legs in water at 44 C. and wrapping the body with blankets. After 50 min of heating the oral temperature had risen to between 99.5 and 100.8 F. The cardiac output had increased by 1.9—4.5 (mean 3.3) liters/min, mainly because of an increase in heart rate. The blood flow through the fingers increased rapidly to reach maximal values soon after heating started, whereas the forearm blood flow, like the cardiac output, increased gradually throughout the heating period. Since the increase in limb blood flow is confined to the skin vessels and since there is no evidence that flow to the internal organs is increased, the total increase in skin flow amounts on the average to 1.8 liters/m2/min.

Submitted on June 2, 1961
Continuous recording of arterial pO2, pCO2, pH, and O2 saturation in vivo
Authors: Meyer John S. , Gotoh F. , Tazaki Y.
Published: December 2017

Methods are described for concurrent, continuous, and automatic recording of paO2, paCO2, apH, and SaO2 of the arterial or venous blood. Measurements were obtained by catheterization of vessels as small as 1 mm in diameter. Graphs of these parameters may be compared with similar measurements in tissue, such as the brain, and correlated with records of function (EKG, EEG, pneumograph). Continuously flowing blood was brought into contact with electrodes and a cuvette for measuring pCO2, pO2, pH, and arterial oxygen saturation by means of catheters and an electrode housing and was then returned to the circulation. For arterial measurements, an arteriovenous shunt was used, for venous blood a mechanical pump is necessary. pCO2 was determined by a membrane-covered pH electrode, pO2 by a membrane-covered polarograph electrode, pH by a small glass electrode, SaO2 by a flow-through oximeter cuvette. Alterations in arterial pH influence SaO2 and paO2 in opposite directions (Bohr effect). Brain tissue parameters reflect changes in arterial pO2, pCO2, and pH but often move independently due to localized changes in tissue circulation and metabolism.

Submitted on October 10, 1960
Blood glucose metabolism in man during muscular work
Authors: Reichard G. A. , Issekutz Bela , Kimbel Philip , Putnam Richard C. , Hochella Norman J. , Weinhouse Sidney
Published: December 2017

A resting human subject was given an intravenous injection of a “trace” dose of glucose-U-C14, and blood and respiratory CO2 samples were collected during ensuing rest, exercise, and rest periods. The CO2 was assayed for radioactivity, and the blood was assayed for total and radioactive glucose and lactate. Total O2 uptake and CO2 output were also measured. In the initial rest period, blood glucose and lactate remained constant while their specific activities declined exponentially. Immediately with onset of exercise, blood lactate level and CO2 excretion increased greatly, but their low specific activities in comparison with that of the blood glucose indicated their origin from endogenous substrates, presumably muscle glycogen. During the subsequent recovery period the specific activities of lactate and CO2 rose while the blood lactate and respiratory CO2 excretion dropped to normal levels. Although the level of blood glucose did not change markedly, its specific activity fell more rapidly during work than during rest, indicating a greater “turnover.” However, this increased turnover began some time after commencement of work and continued into the subsequent recovery period. These findings suggest that the stored muscle glycogen represents the immediate fuel for glycolysis and respiration of working muscle. Subsequently, there is an increased uptake of the blood glucose by working muscle, compensated in the present experiments by an increased hepatic glucose output. The data are in accord with previous suggestions that there is a mechanism whereby muscular work stimulates glucose uptake.

Submitted on July 27, 1961
Voluntary changes in breathing pattern and N2 clearance from lungs
Authors: Bouhuys Arend , Lichtneckert Stefan , Lundgren Claes , Lundin Gunnar
Published: December 2017

Lung N2 clearance curves were recorded in three normal and two symptom-free asthmatic subjects at breathing rates of 10—60/min and tidal volumes of 350—1,950 ml. A change toward more uniform gas distribution at larger tidal volumes was found in one subject. Changes in breathing rate did not affect gas distribution demonstrably. The washout ventilation per liter lung volume (lung clearance index) did not show significant changes with either breathing rate or tidal volume except for an increase at tidal volumes of less than 450 ml. These findings agree with the assumption of a constant dead space volume at tidal volumes within the range studied. The results are of practical importance for the use of the lung clearance index as a measure of the effect of broncho-active substances on the lung ventilation in man.

Submitted on April 28, 1961
A cerebral decarboxylase for 5-hydroxytryptophane in humans
Authors: Sacks William
Published: December 2017

Little or no cerebral decarboxylation of 5-hydroxytryptophane could be found using the in vivo technique developed in this laboratory for determination of human cerebral metabolism. Following intravenous injection of dl-5-hydroxytryptophanecarboxyl-C14 little or no significant venous-arterial C14O2 differences resulted in four normal control subjects and four chronic mental patients. No significant differences were found between the two groups. Levels of arterial blood C14O2 activities showed that 5-hydroxytryptophane was decarboxylated readily by other body tissues. Of four subjects pretreated with 1-benzyl-2-methyl-5-methoxytryptamine (BAS), slightly lowered results occurred with the mental patient pretreated with a double dose of BAS.

Submitted on June 19, 1961