bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical activation and mechanical asynchronism in the cardiac cycle of the dog
Authors: Samet Philip , Bernstein William H. , Litwak Robert S. , Meyer William H. , Lemberg Louis 
Published: December 2017

Dissociation of electrical and mechanical asynchronism in the right and left ventricle of the dog has been studied by simultaneous registration of the precordial electrocardiogram and right and left ventricular pressure curves. Observations were made during sinus rhythm and during digitalis-induced ventricular premature beats with widened aberrant QRS complexes. Measurements were made of the time of onset of isometric contraction in the ventricles, relative to each other, and to the onset of the QRS complex. The results indicate that mechanical asynchronism in onset of isometric contraction is not a necessary consequence of the asynchronous electrical depolarization of ventricular premature systoles. Submitted on November 10, 1958
Passive antibody decay in rabbits under cold or altitude stress
Authors: Trapani Ignatius L. , Campbell Dan H. 
Published: December 2017

Rabbits maintained at an environmental temperature of -15℃ (5℉) for 10 weeks exhibit an increase in the decay rate of passively administered antibody. Rabbits acclimatized at an altitude of 12,470 feet for 30 days show little or no change in passive antibody decay. Protein turnover in these groups of animals is discussed. Submitted on October 27, 1958
Design of a body plethysmograph for studying cardiopulmonary physiology
Authors: Comroe Julius H. , Botelho Stella Y. , DuBois Arthur B. 
Published: December 2017

A body plethysmograph may be used for the measurement in man of thoracic gas volume, airway resistance, instantaneous pulmonary capillary flow and abdominal gas volume; if functional residual capacity (dilution method) and pulmonary resistance (esophageal balloon technique) are measured concomitantly, calculations of ‘trapped’ gas (in the lungs or pleural cavity) and of pulmonary tissue resistance may also be made. The design of the plethysmograph, the electrical circuits and recording devices used and the direct reading attachments for the cathode ray oscillograph are presented together with details of operation and some suggestions for modifications of the original design. Submitted on July 14, 1958
Estimation of pulmonary ventilation with nitrogen and helium, using the mass spectrometer
Authors: Tokuyasu K. , Coblentz A. , Bierman H. R. 
Published: December 2017

Estimation of pulmonary ventilation was attempted by measuring the elimination of nitrogen and helium with the mass spectrometer. Exhalatory concentrations of nitrogen and helium were continuously recorded in each of 12 normal subjects and 10 patients with pulmonary enphysema or space-occupying pulmonary lesions. Uniform values for both slow and rapid uneven ventilation were found in all normal subjects but always less than in emphysematous states. Ratios of effective tidal volume (Vt) and alveolar ventilation volume (f·Vt) to functional residual capacity P = Vt/Vr and Q = f·Vt/Vr were one half or less than those in the normal subject. Smaller values of uneven ventilation were found for helium than nitrogen. Data computed by the theory of 'periodic' ventilation gave greater values for uneven ventilation (Q) and more accurately represented the physiologic conditions than derived by ‘continuous’ ventilation. Submitted on August 7, 1958
Course of mercurial diuresis during Pitressin infusion in mild congestive heart failure
Authors: Grossman Jacob , Gibbons Donald , Weston Raymond E. 
Published: December 2017

In an attempt to assess the influence of diminished filtration rate on the renal response to a mercurial diuretic, with particular emphasis on anisosmotic (free) water reabsorption, six patients with mild congestive failure were given Mercaptomerin, 2 ml, i.v., while receiving a constant infusion of Pitressin 2 μ/kg/hr. During the control collection periods, the anisosmotic water reabsorption was less than that encountered previously in a group of normal subjects. With the onset of diuresis, free water reabsorption rose to the same levels as that of normal individuals and, thereafter, followed the same course. The changes observed are compatible with the hypothesis that free water reabsorption is limited by either of two factors, at low flows, the concentration gradient along the tubule and, at higher flows, the maximal ability of the anisosmotic segment to reabsorb water at a given level of hydration and antidiuretic activity. Submitted on November 13, 1958
Release of intracellular potassium as the physiological stimulus for pain
Authors: Benjamin Fred B. 
Published: December 2017

Evidence is presented that various types of pain-producing stimuli also release intracellular potassium, and that potassium is a pain-producing stimulus. If the potassium releasing process is inhibited or neutralized by calcium, or reversed by increasing cellular uptake of potassium by means of a glucose-insulin combination, the response to painful stimuli is decreased. Calcium appears to have a more immediate effect on pain, while the effects of the glucose-insulin combination become more apparent at a later stage. When the two agents are combined there is no summation of the effect produced by each one individually. Itch is not affected by this glucose-insulin combination. It is suggested that the role of histamine in pain production is via the potassium releasing process. Evidence is considered to indicate that the major effect of a noxious stimulus is not the direct effect on the pain receptor but indirect due to the tissue reaction. Submitted on August 26, 1958
Transcapillary exchange rates in acute and intermittent hyperthermia
Authors: Agersborg H. P. K. , Barlow George , Overman R. R. 
Published: December 2017

The effects of severe, acute and mild, intermittent hyperthermia on the transcapillary exchange rates of Na24 and of K42 have been studied in dogs. Measurements were made before and after a single exposure to a rectal temperature of 42.5℃ for 1 hour, before and after a single exposure to a rectal temperature of 41.5℃ and before and after exposure to the seventh daily rectal temperature elevation to 41.5℃. The sodium exchange rate was seen to be altered in every instance in which a post-hyperthermic measurement was obtained. A measured change in the potassium exchange rate was found to exist only in the animals which had been exposed to daily bouts of intermittent hyperthermia for 7 days. Submitted on February 10, 1959
Calcium-45 binding by human prealbumin
Authors: Johnson Philip C. , Smith William O , Wulff Beulah 
Published: December 2017

Calcium-45 binding by human albumin and prealbumin has been studied. Protein separation was performed by continuous paper electrophoresis. Calcium-45 was added to the fractions and the mixture incubated at 37℃ for 24 hours. Unbound calcium-45 was removed by dialysis against tap water for 16 hours, the pH of the fractions remained between 8.6–9.1 at all times. Aliquots of the fractions were then counted with a micromil gas flow counter. The greatest specific activity was found in several tubes preceding the albumin, i.e. with faster electrophoretic mobility than classical albumin. The calcium-binding ability of this fraction, which has been previously called ‘prealbumin,’ exceeded that of classical albumin by sixfold. Submitted on December 1, 1958
Density, fat, water and solids in freshly isolated tissues
Authors: Allen T. H. , Krzywicki H. J. , Roberts J. E. 
Published: December 2017

Once the initial density, D1, is noted, a single piece of freshly isolated mammalian tissue is analyzed for water and fat. Knowing the densities of water and fat, the tissue's fat-free density, D2, and the dry, fat-free density, D3, can be computed. Among the various types of soft tissues, since D3 is similar, a simple relationship is shown to exist between the fat-free water content and the corresponding density. The biological extremes in a water:fat:protein system thus operate in such a way that the quantity of fat can be predicted from an equation containing three variables, i.e. the initial weight and density of a tissue and its quantity of water. This is of interest in human body composition and also to those who desire to make a sequence of determinations on a single piece of tissue without having to submit a portion thereof to direct analysis of fat, e.g. to express tissue electrolytes and water content on the fat-free basis. Submitted on June 15, 1959
Effect of food deprivation on treadmill running in dogs
Authors: Young D. R. 
Published: December 2017

Effect of food deprivation on endurance capacity was studied in dogs under the following conditions: a) 3 and 5 days of fasting with daily high levels of energy expenditure and b) 15 days of fasting with low daily levels of energy expenditure. Relative maximum performance, i.e. endurance capacity under conditions wherein work dehydration is a limiting factor, is unaffected by 10–15% body-weight loss and hypoglycemia induced by acute food deprivation. Even with weight loss up to 22%, capacity for daily moderate levels of work is well maintained. Absolute maximum performance (water provided exhaustive treadmill running) improves with 5 days of fasting. Associated with 74% increase in endurance capacity, there is an increased mobilization of body tissue for fuel for the working muscles and a large increase in the post-exercise blood glucose concentration. The dog is resistant to starvation ketosis. In animals tested for absolute performance capacity, the average cumulative calorie deficit, including the exhaustive running trial, was 7500 Calories; yet there was no significant change in the level of blood acetone. It is concluded that absolute performance in the dog increases with 5 days of food deprivation; this response is mediated by a unique permissive effect of such treatment particularly on ability to mobilize body energy reserves. Submitted on April 17, 1959
Hemolysis caused by pumps in extracorporeal circulation (in vitro evaluation of pumps)
Authors: Cahill John J. , Kolff Willem J. 
Published: December 2017

To test in vitro the hemolytic properties of pumps used in extracorporeal circulation, a system was made of polyvinyl chloride tubing. Hemolysis was expressed as the rate of accumulation of free hemoglobin in the plasma determined colorphotometrically. Human blood was recirculated with a single pump in the system. Several pumps—the Sigmamotor, the Leonards occlusive roller, the Hercik nonocclusive roller, the MacNeill-Collins and three modifications of the Dale-Schuster were tested under similar conditions. Some pumps in general clinical use produced as much as 19 mg/100 ml of free hemoglobin/hr. A modified Dale-Schuster pump and a Clowes membrane oxygenator also were tested in the system recirculating 800 ml of blood. The hourly production of free hemoglobin was only 3.2 mg/100 ml/hr. The concentration of free hemoglobin was kept constant by exchange transfusion with a modified Dale-Schuster pump and Clowes membrane oxygenator in the system. A formula used to calculate the required amount of blood to be exchanged is presented. Submitted on May 11, 1959
Ulnar nerve conduction velocity and H-reflex in infants and children
Authors: Thomas Juergen E. , Lambert Edward H. 
Published: December 2017

Measurements of conduction velocity of the motor fibers of the ulnar nerve in the segment between the upper part of the arm and the wrist were made in 6 premature infants, 42 full-term newborn infants and 98 children up through the age of 14 years. In premature infants, 21 – 40 days before full term, values ranged from 18 to 22 meters per second with a mean of 21. Full-term newborn infants had velocities that ranged from 21 to 33 m.p.s., with a mean of 28. The values in the newborn were about one-half those of normal young adults, which range from 47 to 73 m.p.s. (mean, 60). By the age of 3 years almost all values were in the lower part of the adult range and, at 5 years, the velocities were not significantly different from those of the adult. These observations are in harmony with information about the diameter of nerve fibers during growth in man. The H-reflex could be elicited by stimulation of the ulnar nerve in almost every newborn infant. By the age of 1 year and thereafter it could rarely be elicited. Between the elbow and wrist, afferent fibers subserving this reflex conducted with a mean velocity of 30 m.p.s. Data on the action potential of the hypothenar muscles, residual latency of conduction in the ulnar nerve, latency of the H-reflex and conduction in the peroneal nerve in infants and children are compared with those on adults. Submitted on July 15, 1959
Serum lipoprotein statistics in populations and individuals
Authors: Tamplin Arthur R. , Tandy Robert K. 
Published: December 2017

Age and sex trends in individual and population statistics of the low density serum lipoproteins are presented and discussed. The data disclose a lack of conformity between populations which reasonably could be considered comparable random population samples. The data also indicate a metabolic independence of the sf 0 – 20 and the sf 20 – 400 lipoprotein classes and the suggestion is introduced that this is due to a metabolic independence of cholesterol and triglycerides. Submitted on April 13, 1959
Effects of a short period of training of varying severity on some measurements of physical fitness
Authors: Durnin J. V. G. A. , Brockway J. M. , Whitcher H. W. 
Published: December 2017

The experiment attempted to measure whether there was an improvement in physical fitness through varying degrees of exercise which had a duration of only 10 days. Forty-four untrained young men acted as subjects. They were divided into four groups; one group acted as controls and did only a minimum of exercise, while the men in the other three groups walked 10 km, 20 km and 30 km daily, respectively. ‘Fitness’ was assessed by measurements of pulmonary ventilation, oxygen extraction, oxygen consumption and heart rate during a standardized physical test on the treadmill. Recovery heart rate was also measured. The test was done before, during and after the period of training. The use of a submaximal exercise test and the significance of some cardiorespiratory measurements is discussed. The group of men walking 20 km daily showed the most marked improvement in ‘fitness,’ with a significant lowering of pulmonary ventilation, oxygen consumption and heart rate during the test. Submitted on May 8, 1959
Hematological changes during muscular activity and recovery
Authors: De Lanne R. , Barnes J. R. , Brouha L. 
Published: December 2017

Hematological changes were studied in men and women during exercise and recovery under three environmental conditions. An erythrocytosis due to hemoconcentration was observed which was not followed by hemodilution and was not accompanied by the destruction or generation of red cells. Hemoconcentration was influenced by exercise, but not by thermal stress, in spite of greater water losses in warm environments. Sex differences at rest were found for red and white cells, but the pattern of the reactions to exercise was similar for both sexes. Leucocytosis resulted from exercise and heat exposure, with a greater effect of exercise in the females. This is due to increased capillary circulation, hemoconcentration and lymphatic pressure, but not to the stimulation of leucopoietic centers. Changes in the systemic circulation followed by an increase of lymph flow explain the lymphocytosis. Granulocytosis occurs later, persists longer, and may be related to the concentration of circulating corticosteroid hormones. Submitted on August 24, 1959
Pulmonary resistance and compliance with concurrent radioactive sulfur distribution in dogs breathing S35O2
Authors: Balchum Oscar J. , Dybicki Jerzy , Meneely George R. 
Published: December 2017

Ten dogs breathed S35O2 via a tracheal cannula in concentrations ranging from 1.8 to 148 p p.m. There was a decrease in the compliance of the lungs and thorax after 10–15 minutes of inhalation, and an immediate and marked increase in the nonelastic resistance to breathing. S35 was found to be highest in concentration in the trachea, lungs, and hilar lymph nodes, and next highest in the kidneys and esophagus. A relatively uniform and low concentration was noted in other tissues, such as the heart muscle, liver, spleen and striated muscle. S35O2 when inhaled was absorbed quickly, distributed widely to many tissues and readily gained access to many tissues, including the brain. Submitted on April 28, 1959
A method for continuous recording in vivo of blood oxygen tension
Authors: Kreuzer F. , Harris E. D. , Nessler C. G. 
Published: December 2017

A catheter-type Po2 electrode has been developed which permits the polarographic continuous recording of the blood oxygen tension in vivo. The electrodes have the size of ordinary cardiac catheters and yield continuous Po2 tracings in the animal over several hours, with a standard deviation of less than 3%. Model experiments assessed the dependency of the polarographic readings on temperature and showed that static pressure was without effect, but pulsatile pressure caused mechanical deflections depending on the rate of pressure change, and the readings became constant with linear velocities of more than 8–10 cm/sec. In experiments with anesthetized dogs, the readings were calibrated on arterial blood samples analyzed in an in vitro polarograph. With changing inspiratory o2 concentrations, the time for reaching a new equilibrium was found to be 3–4 minutes. The course of the alveolar-arterial o2 gradient was studied over the whole range of inspiratory o2 concentrations. The value of this gradient in the higher o2 ranges permitted the estimation of venous admixture in the anesthetized dog; the average was 5.5% of the cardiac output. Submitted on February 20, 1959
Determination of oxygenated, mixed venous blood CO2 tension by a breath-holding method
Authors: Knowles John H. , Newman William , Fenn Wallace O. 
Published: December 2017

At the end of a normal expiration the subject inhaled a given volume of gas mixtures containing different concentrations of CO2 in O2 from 5 to 17%. These were held in the lung for 3 and then again for 12 seconds and were then expired and analyzed. Analyses were made with an infrared analyzer and times were obtained from the graphical record. If the rate of change of CO2 tension is plotted against the mean CO2 tension a straight line results which passes through zero rate at the tension which equals the tension of CO2 in the mixed oxygenated venous blood. From the slope of this straight line it is possible to calculate the cardiac output if the lung volume and slope of the CO2 dissociation curve of the blood are known. Data are presented from 37 experiments on 10 subjects. The method is believed to be theoretically sound but has not been validated as a practical clinical method. Occasional erratic points were obtained, especially in untrained subjects. The standard error of the mean value for venous CO2 tension was 1.9 mm Hg. Submitted on July 13, 1959
Effect of sleep deprivation on plasma 17-hydroxycorticosteroids
Authors: Murawski Benjamin J. , Crabbé Jean 
Published: December 2017

Paid volunteers, 18 male college students, were deprived of sleep for one night on two separate occasions when alone. On a third occasion they were asked to stay up all night in groups of four. Plasma concentrations of 17-hydroxycorticosteroids at 8:00 a.m. following the nights without sleep were 4–5 μg lower than control values (significant at .01 level). The noon values after sleep deprivation in a solitary setting were not significantly different from the corresponding control values. When subjects stayed up with three other people, the noon values tended to be higher. Urinary 17-hydroxycorticosteroid levels showed a decrease following the nights without sleep, but this decrease did not reach statistical significance (between the .10–.05 level). Submitted on May 21, 1959
Cardiovascular adjustments in dogs during continuous pressure breathing
Authors: Lenfant Claude , Howell Barbara J. 
Published: December 2017

Pressure changes in the pulmonary artery and vein, thoracic vena cava, aorta and intrapleural space as well as the cardiac output were measured in anesthetized dogs subjected to continuous airway pressures varying between -25 to +25 cm H2O. Pulmonary and systemic resistances were calculated. During positive airway pressures the pulmonary artery, vein and vena cava pressures approximately paralleled changes in intrapleural pressures. Cardiac output and aorta pressures decreased; systemic and pulmonary flow resistances markedly increased. During negative airway pressures the pulmonary vessels and vena cava pressures decreased but no longer paralleled the changes in intrapleural pressures. It is assumed that these vessels reached their limit of distensibility. While aortic pressures decreased, cardiac output, systemic and pulmonary resistances remained essentially unchanged. Submitted on January 14, 1960
Measurement of hepatic blood flow in the unanesthetized dog by a modified bromsulphalein method
Authors: Shoemaker William C. 
Published: December 2017

Possible errors of the bromsulphalein method for estimation of hepatic blood flow are enumerated and an analytic method which takes into account the amount of hemolysis present in the samples is described. Improved analytical accuracy allows flow measurements to be carried out at lower bromsulphalein levels, which theoretically allow less extrahepatic bromsulphalein loss and provide larger gradients relative to the circulating level. A preparation for the study of hepatic blood flow and regional hepatic metabolism in the chronic unanesthetized dog is described. Modifications of the bromsulphalein method are proposed for use in this experimental preparation; these modifications include an attempt to obviate the problems of the retrograde hepatic vein catheter technique and a direct measurement of the portal-hepatic venous bromsulphalein concentration gradient. Comparison of hepatic blood flow measurements by the modified bromsulphalein method with direct measurements of flow in the in situ perfused liver have shown comparable results. Submitted on September 18, 1959
Cutaneous vascular responses in finger and forearm during rising ambient temperatures
Authors: Senay L. C. , Christensen M. , Hertzman A. B. 
Published: December 2017

During slowly rising ambient temperatures, digital vasodilatation often preceded that in forearm skin; the two vasodilatations proceeded together in spring but not in summer experiments. The curvilinear relation of local skin temperature to local skin blood flow in the forearm often showed an abrupt inflection, suggesting the appearance of an additional influence on the vessels; however, a regular relation to local sweating was not apparent, vasodilatation in forearm skin often continued to increase even when local skin temperature had stabilized or fallen slightly, and the forearm vascular events were prevented by local cooling. During repeat cycles of ambient temperature, complete dissociation of the cutaneous vascular events in finger and forearm and of forearm vasodilatation and sweating often occurred. Digital vasomotor waves were not accompanied by similar waves in forearm skin. Of multiple factors possibly controlling the forearm skin circulation, the local temperature seemed most important. The maximum vasodilatation in forearm during heat exposure was not augmented by acetyl-β-methylcholine. Submitted on January 18, 1960