bluuebunny/crossref_metadata_2025_split huggingface dataset:
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