bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow rate of erythrocytes in the capillaries of the lung
Authors: Schlosser Dieter , Heyse Ernst , Bartels Heinz 
Published: December 2017

The rate of blood flow in the capillaries of the rabbit lung was investigated by cinematographic methods and found to be 0.75 mm/sec during artificial respiration with air applied with a Starling pump during the filming. Using our measured value for the average capillary length of 68 μ, the average contact time for the erythrocytes is 0.1 sec. If we assume the capillaries to have a length of 100 μ, the contact time would amount to 0.15 ± 0.05 sec. The discrepancy with the saturation time obtained from in vitro experiments is discussed. It is shown that insufflation increases the capillary blood flow in the lungs. blood flow; velocity; rabbit; microcinematography Submitted on February 24, 1964
Evidence for adrenal insufficiency in acutely stressed captive monkeys
Authors: Nagle Jack P. , Cammock Earl E. , Nyhus Lloyd M. , Harkins Henry N. 
Published: December 2017

A number of postoperative complications in Macaca nemestrina suggested possible adrenal insufficiency secondary to chronic stress. Adrenal function was assessed by use of plasma 17-hydroxycorticoids, total eosinophil counts, and ACTH-response tests. Surgery or anesthesia resulted in a rise in plasma 17-hydroxycorticoids and a fall in total eosinophils in the majority of monkeys, and all of these animals demonstrated at least a 50% decrease in the total eosinophil count 4 hr following the intramuscular administration of ACTH. However, in three monkeys this type of response did not occur following one or both of the tests that were done. These three animals, unlike the others, presented one or more of the following complications during the poststress period: lethargy, failure to eat properly, diarrhea, and diuresis. These findings indicate that the stress of captivity may deplete adrenal reserve and alter normal physiological responses. primates (Macaca nemestrina); primates, adrenal reserve in primates, total eosinophil counts; primates, corticosteroid levels; adrenal reserve, evaluation of adrenal function, postoperative; captivity, adrenal exhaustion in Submitted on October 21, 1964
Dynamic accuracy of the electromagnetic flowmeter
Authors: O'Rourke M. F. 
Published: December 2017

Dynamic calibration of electromagnetic flowmeters was performed by resolving the output signal when sinusoidal flow of known characteristics was pumped through the probe. In two instruments amplitude and phase were found to be frequency dependent in the range 0–20 cycle/sec; the magnitude of these effects was not insignificant as many have assumed. In a sine wave instrument using a variety of probes, both amplitude and phase increased linearly with frequency: the former increasing by 0.57% per cycle per second, the latter by 3.6° per cycle per second. In the square wave flowmeter at 0 damping, amplitude decreased significantly above 5 cycle/sec, while phase lag increased by 4.9° per cycle per second. These effects are concluded to be due to the output filtering network. In the sine wave instrument it was demonstrated that magnetic field nonuniformity within the probe did not alter the accuracy in recording steady or oscillatory flow. It was thus possible to construct a small short flowmeter probe having narrow electromagnet coils, and it is expected that this probe should cause minimal interference to pulsatile flow patterns. magnetic fields flowmeter probes; frequency-response flowmeter Submitted on April 16, 1964
Role of skin and of core temperatures in man's temperature regulation
Authors: Wyndham C. H. 
Published: December 2017

The response characteristics have been studied of the curves relating heat conductance and sweat rate to change in rectal temperature at different levels of skin temperature, and vice versa. The increase in these responses with deviation in rectal temperature from the “neutral” setting is highly nonlinear; the neutral point and the curve shift to the right and the slope decreases with lowering of skin temperature and vice versa when it is raised. With further deviation of rectal temperature these responses reach maximum values, i.e., become “saturated.” All of these features are analogous to servomechanisms with negative feedback, giving sensitive and stable control. Control of these responses by skin temperature is more linear, characterizing passive control systems which are insensitive and less stable. Quantitatively, the effect at skin temperature of 26 C of 1 C rise in rectal temperature on heat conductance and sweat rate is 10 times greater than the same rise in skin temperature; at a neutral skin temperature of 33–34 C, a rise of 1 C in rectal temperature is 6–7 times greater; at a high skin temperature of 36 C, a rise in rectal temperature of 1 C is 4–5 times greater. relationship between heat conductance and a change in either rectal or skin temperatures; relationship between sweat rate and a change in either rectal or skin temperatures; response characteristics of curves relating heat conductance to change in either rectal or skin temperatures; response characteristics of curves relating sweat rate to change in either rectal or skin temperatures; assessment of the contribution of skin and rectal temperatures to man's temperature regulation Submitted on October 22, 1963
Pulmonary hypertension with muscular exercise in the newborn calf
Authors: Reeves John T. , Leathers James E. 
Published: December 2017

Two types of pulmonary hypertension occur with muscular exercise (walking) in the calf on the day of birth: a) Pulmonary arterial pressure increased in all calves during exercise. The increase was greatest in the youngest calves. Pulmonary arterial pressures did not rise to systemic levels and arterial oxygen saturations remained normal. Pulmonary hypertension subsided in 2 min after stopping exercise. Pulmonary arterial pressure rose again when exercise was repeated. Both an increased pulmonary flow and pulmonary vasoconstriction may have contributed to the increased pulmonary arterial pressure during exercise. b) Pulmonary hypertension was observed in five calves for 30-50 min after exercise ceased. When pulmonary arterial pressure exceeded aortic pressure, arterial oxygen unsaturation occurred. This pulmonary hypertension which occurred only once per calf resembled"spontaneous" pulmonary vasoconstriction observed in resting calves on the day of birth. It is postulated that some substance remaining in the lung after fetal life, rather than the acutely reduced oxygenation of mixed venous blood, initiated this pressor response. hypoxia; pulmonary vasoconstriction Submitted on May 11, 1964
An analysis of the mechanics of phonation
Authors: Cavagna G. A. , Margaria R. 
Published: December 2017

The mechanical work done by the chest in phonation has been measured together with the sound intensity level. The regulation of the sound intensity is done by regulating the intrapulmonary pressure. This is achieved at high intensity levels through the activity of the respiratory muscles that, together with the elastic recoil of the chest, sustain the work of phonation. At sound intensities below a critical level an additional mechanism for changing the intensity is given by a fine regulation of the opening of the glottis, thus allowing more air to escape without contributing to sound production. The contribution of the respiratory muscles, of the chest elasticity, and of the opening of the glottis to phonation at different intensity levels depend on the degree of inflation of the chest. The efficiency of phonation, as of sound production in mechanical models, seems to increase with increasing intensity and pitch. voice production; work done by chest during phonation; mechanical models of glottis generator; subglottic pressure as a function of sound level; air flow through glottis during phonation; efficiency changes of sound production; variation of sound intensity by regulating opening of glottis; variations of the area of glottis depending on extent of elastic recoil of chest Submitted on February 10, 1964
Precise control of stimulation parameters in low impedance conditions
Authors: Mills L. W. , Swett J. E. 
Published: December 2017

A system is described for accurate control of stimulation parameters in conditions where impedances between 100 and 30,000 ohms are encountered across the secondary of a stimulus isolation transformer. The dual-channel stimulator is constructed mainly from Tektronix 160 series pulse and waveform generators. The stimulator was designed primarily for evoked potential studies in the nervous system with peripheral nerve stimulation but will operate equally well with concentric or needle electrodes in deep brain structure, providing that total electrode-tissue impedances are kept within the stipulated limits. The unique feature of the stimulator is embodied in the operational amplifier interposed between the Tektronix stimulus pulse generator and the primary of the isolation transformer. This system is designed to read directly in stimulus intensities relative to any stipulated physiological threshold. Absolute stimulus voltages may be continuously monitored to ± 3% accuracy. The impedance matching characteristics of the described system will permit effective stimulation of excitable tissues while maintaining stimulus control by the operational amplifier settings within ± 1%. The large range of pulse durations, stimulus intensities, and the use of more than one type of stimulus waveform, have been sacrificed in favor of maintaining rigid control over pulse waveforms and amplitudes with passage of large stimulating currents at low intensities. This system comes close to achieving those qualities embodied in the ideal constant voltage stimulator. physiological stimulation; biological stimulator; low impedance stimulation; Tektronix-adapted units for biological stimulation; isolated stimulator; nerve stimulator; physiological threshold stimulator Submitted on July 10, 1964
A photopotentiometric transducer for detecting in vitro muscle contractions
Authors: McIntosh Max , Duggan Dennis E. , Watt Dean D. , Goodson Louis H. 
Published: December 2017

In vitro muscle contractions can be detected and recorded by using a light-sensitive solid-state potentiometer as a transducer. The amount of light reaching the photosensitive potentiometer is controlled by movement of a shield across the potentiometer in response to muscular contractions. The apparatus is relatively frictionless, sensitive, inexpensive, and needs little or no amplification when the signal is transmitted to ordinary recorders. photosensitive solid-state potentiometer; frictionless transducer; Schultz-Dale reaction; hypersensitivity; anaphylaxis Submitted on August 10, 1964
Influence of a tranquilizer on temperature regulation in man
Authors: Iampietro P. F. , Fiorica V. , Dille R. , Higgins E. A. , Funkhouser G. , Moses R. 
Published: December 2017

The effects of a tranquilizing drug of the propanediol group, meprobamate, on thermal balance of men exposed to a cold (50 F, 10 C), hot (110 F, 43.3 C), or neutral (80 F, 26.7 C) environment have been investigated. Results show that a single dose of meprobamate (800 mg) has no effect on temperature regulation of men resting in a neutral environment. During exposure to hot or cold environments, however, the drug groups showed impairment in thermal balance. In the cold, heat production and core temperature of the drug group were lower than those of the placebo group. In the heat, only moderate elevations in the core temperatures of the drug group were detected. Possible physiological mechanisms responsible for these differences are discussed. human exposure to heat and cold; drugs and temperature regulation; catecholamines in heat and cold; meprobamate; heat; cold Submitted on October 9, 1964
Temperature regulation and cold acclimation in the golden hamster
Authors: Pohl Hermann 
Published: December 2017

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964
Comparison of maximal oxygen uptake values determined by predicted and actual methods
Authors: Glassford R. G. , Baycroft G. H. Y. , Sedgwick A. W. , Macnab R. B. J. 
Published: December 2017

Twenty-four male subjects aged 17–33 were given three direct tests of maximal oxygen uptake and one indirect test. The direct tests were those of Mitchell, Sproule, and Chapman (treadmill); Taylor, Buskirk, and Henschel (treadmill); and Åstrand (bicycle ergometer). The indirect test was the Åstrand-Ryhming nomogram (bicycle ergometer) employing heart rate response to submaximal work. In addition, the Johnson, Brouha, and Darling physical fitness test was administered. The two treadmill tests and the indirect test yielded significantly higher mean values than did the direct bicycle test. However no other significant differences in mean values occurred. Correlation coefficients between the various oxygen uptake tests as well as the fitness test were all found to be significant (.62–.83), i.e., greater than zero. No correlation obtained proved to be significantly greater than any other. The results indicate that direct treadmill tests, employing greater muscle mass, yield higher maximal oxygen uptake values (8%) than does the direct bicycle ergometer test. The Åstrand-Ryhming nomogram appears to produce a good estimation of maximal oxygen uptake, in a population unaccustomed to cycling. erobic capacity; exercise; heart rate Submitted on September 17, 1964
Metabolism and the protection by anesthesia against toxicity of O2 at high pressure
Authors: Bean John W. , Zee Dominic 
Published: December 2017

Experiments were performed on rats to determine whether the protection which anesthesia (sodium pentobarbital) affords against convulsions in oxygen at high pressure (OHP) of 70–75 psi extends to the pulmonary damage and, if so, whether such protection is due simply to the depression of general metabolism. These experiments showed that anesthesia protected against both the pulmonary damage and the convulsions and that this protection was equally well pronounced whether the metabolic depression was or was not counteracted and elevated by dinitrophenol, L-thyronine, or direct tetanic stimulation of muscle. The results support the conclusion that such protection is not due simply to the depression of general metabolism as has been claimed. They also imply that the potentiation of pulmonary damage in OHP by thyroid and CO2 is not a direct effect but rather is of central origin. The close association between the pulmonary damage and convulsions in OHP justifies the inference that these effects are not separate entities, as has been claimed, and point to the importance of central and neurogenic factors in the causation of this pulmonary damage. hyperbaric oxygenation; oxygen poisoning at high pressure; oxygen convulsion in relation to pulmonary damage; pulmonary edema and congestion in oxygen at high pressure; neurogenic factors and toxicity of oxygen at high pressure; direct and neurogenic effects of oxygen at high pressure on the lungs; pCO2and oxygen poisoning; thyroid and pulmonary damage in oxygen poisoning; protection against oxygen toxicity by pentobarbital, urethan, alpha chloralose, and propylene glycol Submitted on September 11, 1964
Impedance measurement of tidal volume and ventilation
Authors: Hamilton L. H. , Beard J. D. , Kory R. C. 
Published: December 2017

Thoracic impedance changes have been used to measure tidal volume and ventilation in normal subjects. Tidal volume was measured directly and total ventilation was accumulated with a diode voltage pump. The size, shape, and placement of the electrodes affected the reliability with which the system measured ventilation. A high correlation was demonstrated between transthoracic resistance or capacitance changes and ventilation when special narrow ridged electrodes were applied bilaterally on the thorax. The variability between accumulated impedance changes and ventilation measured with a spirometer had a standard deviation less than ±6% of the ventilation. A linear relationship was demonstrated between lung volume change and impedance change for subjects in the standing, sitting, or supine positions, whether the breathing pattern was normal, predominantly thoracic, or predominantly abdominal. transthoracic impedance; tissue resistance; tissue capacitance Submitted on June 24, 1964
Dipalmitoyl lecithin: studies on surface properties
Authors: Kuenzig Marian C. , Hamilton Robert W. , Peltier Leonard F. 
Published: December 2017

A preparation of synthetic dipalmitoyl lecithin has been devised whose activity on a Wilhelmy surface balance is similar to that of extracts from normal lungs. An ethanol solution of lecithin is precipitated with albumin, and a drop of the suspension containing approximately 0.04 mg lecithin is spread on the surface of 0.9% NaCl in the trough of the balance. This preparation appears to be insensitive to oxidation and when run under humidified air gives reproducible results. It has a low minimum surface tension (5—10 dynes/cm) when compressed to 20% of the original surface area and exhibits considerable hysteresis on re-expansion. Addition of certain lipids to the surface film produces changes similar to those caused by addition of these lipids to cat lung extracts. surface tension; surface activity; pulmonary surfactant Submitted on September 8, 1964
Resistivity of flowing salt solutions
Authors: McFee Richard , Spatuzzi Anthony R. 
Published: December 2017

The longitudinal resistance of salt solutions flowing in rigid tubes is found to change by less than frac14 of 1% for flow velocities up to and exceeding the turbulent rate. The reduced resistance of flowing blood as contrasted to stationary blood is thus not due to altered resistance of the fluid proper rheoencephalogram; blood flow; impedance; plethysmography Submitted on November 3, 1964
Normal respiratory and circulatory values in the cat
Authors: Nadeau R. A. , Colebatch H. J. H. 
Published: December 2017

Seventeen cats were studied under chloralose anesthesia. In 6 cats a polyethylene catheter was placed in the main pulmonary artery via the external jugular vein. In 11 other cats, a right thoracotomy was done under artificial ventilation, and small nylon catheters were inserted into the main pulmonary artery and the left atrium via the vessels of the right upper lobe, after which the chest was closed. While the animal breathed air through a closed circuit with a constant supply of oxygen, respiratory rate, tidal volume, and oxygen consumption were recorded on a smoked drum. Oxygen consumption averaged 111.4 ± 28.9 ml/min per m2. Femoral arterial and pulmonary arterial blood oxygen contents were measured by a modification of the Barcroft-Haldane method with Warburg manometers and averaged 14.18 ± 3.68 and 9.36 ± 1.39 vol %, respectively. The cardiac output was measured according to the Fick principle and averaged 2.10±.70 liters/min per m2. Heart rate, femoral artery blood pressure, pulmonary artery blood pressure, left atrial pressure, end-expiratory pleural pressure, and femoral artery blood oxygen tension were also determined. No significant difference was noted between thoracotomized and intact cats. Cardiac output values, however, were significantly greater than those previously reported for this species. oxygen consumption; cardiac output Submitted on October 8, 1964
Effect of oxygen breathing at atmospheric pressure on pulmonary surfactant
Authors: Giammona Samuel T. , Kerner Donald , Bondurant Stuart 
Published: December 2017

To evaluate the effects of oxygen breathing at atmospheric pressure on pulmonary surfactant, cats, rabbits, and rats were continuously kept in 98% oxygen until death occurred. Pulmonary surfactant was extracted by mincing of the lung and by foam fractionation of the lung. Surface tension of the extracts was measured on a Wilhelmy balance. Lung extracts prepared by both methods from the cats and rabbits kept in oxygen had greater surface tension than lung extracts from control animals. Surface tension of extracts prepared by foam fractionation of lungs of rats kept in oxygen did not differ from that of extracts of lungs of control rats, whereas surface tension of extracts prepared by mincing lungs of rats kept in oxygen had minimum surface tension greater than that of lung extracts of control rats. This species difference in the effects of oxygen breathing on pulmonary surfactant may reflect a difference in the pathogenesis of oxygen intoxication. oxygen intoxication; surface tension Submitted on October 19, 1964
Concept and measurement of ventilatory sensitivity to carbon dioxide
Authors: Dejours P. , Puccinelli R. , Armand J. , Dicharry M. 
Published: December 2017

Four resting subjects breathed 0, 1, 2.5, and 4% CO2 diluted in air for 25 min. Ventilation, Po2 and Pco2 of alveolar and expired gases were measured. One can represent on a Po2-Pco2 diagram, as Rahn and Fenn have done, some features of the reaction to CO2, and plot lines of “ventilatory isosensitivity to CO2.” The relation between experimental points and these lines shows why “ventilatory CO2 sensitivity,“ DeltaVa/DeltaPaCOCO2, for normal conditions cannot be quantified by the classical procedure of giving one or several percent CO2 to breathe. CO2 sensitivity nonetheless exists normally, since in subjects breathing mixtures containing a few mm Hg CO2, PaCOCO2 is practically unchanged, while PaOO2 rises by several mm Hg. The difficulties of accurately measuring DeltaVa/DeltaPaCOCO2 suggest caution in accepting some mathematical developments often applied to raw data, and in taking this ratio as a true index of ventilatory CO2 sensitivity, particularly when measurements made with high inspired CO2 concentration are used to interpret the regulation of normal respiration. alveolar pathway during CO2 breathing; control of breathing; hypercapnia; O2-CO2 diagram Submitted on December 11, 1964
Effects of compression on composition and absorption of tissue gas pockets
Authors: Van Liew Hugh D. , Bishop Beverly , D. Pio Walder , Rahn Hermann 
Published: December 2017

Data with subcutaneous gas pockets in rats and theoretical considerations lead to the following conclusions concerning the effects of compression on preformed gas bubbles in the body: 1) Besides mechanically decreasing bubble size, compression causes an additional volume decrease due to readjustment of water vapor, CO2 and O2 volumes in the bubble. 2) The pocket-to-tissue Pn2 difference (in the stabilized condition in which tissue Pn2 equals arterial Pn2) is almost completely dependent on alveolar oxygen, not on compression per se. Compression with air elevates alveolar O2, but the same nitrogen difference could be gained by inhaling oxygen-enriched gas at lower pressures. 3) Compression causes an increased pocket-to-tissue Pn2 difference which hastens N2 absorption, but at the same time decreases surface area and thus tends to slow absorption. hyperbaric; oxygen; decompression sickness; gas bubbles; high pressure Submitted on October 26, 1964