bluuebunny/crossref_metadata_2025_split huggingface dataset:
Renal clearance and plasma protein binding of oxytetracycline in man
Authors: Kaplan S. A. , Yuceoglu A. M. , Strauss J. 
Published: December 2017

The clearance of oxytetracycline was measured in eight children, four of whom also received glucosamine. The average clearance of oxytetracycline was 163.7 ml/min./1.73 m2 in the eight experiments and the average clearance of inulin was 115.8 ml/min/1.73 m2. About two-thirds of the oxytetracycline appearing in the urine was filtered at the glomeruli. One-third was secreted by the tubules. About three-fourths of the oxytetracycline in human plasma was found to be dialyzable and one-fourth bound to protein. Glucosamine (40 mg/kg) administered for 24 hours did not significantly modify the renal tubular secretion of oxytetracycline. Note: (With Technical Assistance by S. Graziano and R. Kanter) Submitted on April 22, 1959
Pitfalls of the continuous histamine test for gastric secretory inhibition
Authors: Shapira Daniel , Cross Cecil , Morgenstern Leon , State David 
Published: December 2017

Dogs with Heidenhain pouches were given histamine at a constant rate for 6 hours or longer. Output of HCl from the pouch was measured every half hour, and each secretory response was divided into control and test phases, according to the procedure of the continuous histamine test. However, no inhibitory factor was introduced. In 32 experiments the rate of HCl output reached a stable level during the control phase, but many responses failed to show stability throughout the test phase. Frequently, there was a pronounced drop in rate of HCl output below the pre-established control level. With the continuous histamine test, it is sometimes assumed that any appreciable drop in rate of HCl output during the test phase is attributable to the factor being tested and that it represents inhibition of the histamine-induced response. The results of the present study illustrate that this premise may be invalid under certain conditions. If control studies are not performed with the continuous histamine test, spontaneous drops in rate of HCl output are apt to be misinterpreted as evidence of inhibition. Note: (With the Technical Assistance of S. Mehta) Submitted on September 8, 1958
An alveolar pCO2 control system: its use to magnify respiratory depression by meperidine
Authors: Lambertsen C. J. , Wendel H. 
Published: December 2017

A system was devised combining means of a) automatic sampling of end-tidal gas, b) rapid analysis of samples gas for Co2 concentration and c) manual or automatic modification of per cent Co2 in succeeding inspirations to permit maintenance of alveolar pCo2 at desired levels above the Co2 tension natural for a particular experimental situation. By imposing a fixed, elevated alveolar pCo2 upon a subject, effects of drugs or physiological stresses upon Co2-sensitive functions can be evaluated, unmasked by the compensatory alterations of alveolar and arterial pCo2 which normally result from changes in alveolar ventilation or metabolism. Validation of alveolar pCo2 control in 16 normal subjects, using arterial pCo2 as a reference standard, revealed no significant difference between the imposed end-tidal pCo2 and the pCo2 of arterial blood. Use of the pCo2 control system to evaluate the dynamics of meperidine effect on respiration in normal men indicated sufficient magnification of the effect of meperidine on respiratory minute volume to permit use of the method for comparative studies of rate of onset, time of peak effect and rate of disappearance of the action of meperidine on respiration. Submitted on July 9, 1959
Temperature distribution over the human head, especially in the cold
Authors: Edwards Merrill , Burton Alan C. 
Published: December 2017

Two separate practical problems are the reduction of the total heat loss of the head, as by insulated helmets, and protection from frostbite, as by face masks. Solution of both problems benefits from knowledge of the distribution of skin temperature. Temperatures were measured with thermocouples at several points on three subjects, in the steady state, at environmental temperature of 0°C. Topographical differences were similar for the three subjects. Temperatures at a large number of points were measured in a single subject, and isothermal maps were drawn from the results. They show that the areas needing most protection from frostbite are the tip of the nose, the rim of the ears, the chin and the cheekbones. The areas of highest temperature (greatest heat loss) are those covered by the conventional insulated helmets. A face mask need not cover the area round the mouth where tactile sensitivity may make it uncomfortable. The isothermal map is correlated with the anatomical distribution of arterial blood supply. Submitted on August 3, 1959
Attempt to demonstrate the distribution component of the alveolar-arterial oxygen pressure difference
Authors: Haab Pierre , Piiper Johannes , Rahn Hermann 
Published: December 2017

Under normal conditions, the alveolar-arterial oxygen pressure difference (A-a difference) is believed to be due primarily to two causes, venous admixture (shunt component) and variation in ventilation-perfusion ratios (distribution component). In order to assess quantitatively the role played by the latter factor, the difference in O2 tension between end-tidal air and arterial blood was measured in anesthetized dogs under two conditions: a) at normal ambient pressure (Pb = 747 mm Hg), breathing air; b) at low ambient pressure (Pb = 192 mm Hg), breathing 100% O2. The essential feature of this procedure is that, while the inspired O2 tension is identical in both conditions, there is no nitrogen in the gas inspired at low ambient pressure. Theoretical analysis indicates that, if all or part of the A-a difference measured under condition a is due to a variation in ventilation-perfusion ratios, then this difference must be significantly reduced under condition b. Such a decrease in the A-a difference should provide an index of the magnitude of the distribution component. However, in our experiment, the A-a difference was found to be the same in both conditions. Therefore, our results do not support the hypothesis that there exists a large distribution component of alveolar-arterial difference. Submitted on October 21, 1959
Respiratory and cardiovascular alterations during the process of anoxic death in the newborn
Authors: Cassin S. , Swann H. G. , Cassin B. 
Published: December 2017

A systematic investigation was conducted during the process of anoxic death in newborn pups, rabbits and kittens less than 24 hr. old. Simultaneous measurements of respiration, heart rate and blood pressure were made. Considerable individual variation in the respiratory responses of newborn animals breathing nitrogen was noted. Under hypoxic conditions, respiratory failure may follow circulatory failure in the adult, whereas in the newborn, respiratory failure always occurred long before circulatory failure. The effect of anoxia on the cardiovascular system of the newborn at the time of the last breath was not as pronounced as might have been anticipated. Great individual differences with respect to blood pressure and heart rate throughout the period of anoxia were noted. The systolic blood pressure, on the average, was seen initially to fall more rapidly than the diastolic blood pressure or heart rate; it then slowly tapered off. The circulatory system was noted to function, although at hypotensive levels, for long periods of anoxia. Submitted on June 29, 1959
Use of the restrained rat technique for study of the antiulcer effect of drugs
Authors: Hanson H. M. , Brodie D. A. 
Published: December 2017

Five anticholinergic drugs, atropine sulfate, diphenmethanil, mepiperphenidol, propantheline and scopolamine methiodide, were studied for their effects on gastric ulcers in rats produced by the restraint technique. All the drugs significantly decreased ulceration; scopolamine methiodide appeared to be the most potent drug tested, followed by propantheline, atropine, diphenmethanil and mepiperphenidol. Three central nervous system depressants, chlorpromazine, benactyzine and pentobarbital, all decreased the incidence of ulcers with no differences in potency. Acetazolamide administered daily for 5 days had no effect on ulceration. Prednisolone administered daily was found to increase the time required for recovery from restraint-produced ulcers. Submitted on November 6, 1959
Control of respiratory frequency
Authors: Mead Jere 
Published: December 2017

Previous work has shown that for a given level of alveolar ventilation there is a particular respiratory frequency which is least costly in terms of respiratory work. There is also a particular frequency, usually a different one, which is least costly in terms of average force of the respiratory muscles. Evidence is presented that in the resting guinea pig and in man at rest and during exercise natural breathing takes place at frequencies approximating the second optimum. From additional observations on the effects of changing the mechanical characteristics of the respiratory system on respiratory frequency it is concluded that the principal site of the sensory end of the control mechanism is in the lungs. Submitted on November 19, 1959
Catecholamine excretion in men exposed to cold
Authors: Arnett Elizabeth L. , Watts Daniel T. 
Published: December 2017

Male subjects were subjected to a cold stress of 6.5°C for 1 hour. One-hour urine samples were collected in acid immediately before and after the exposure. Physiological responses such as blood pressure, body temperature, pulse rate and pupil size were recorded under this hypothermic stress. Epinephrine and norepinephrine were extracted from the urine and determined fluorometrically. In addition, the epinephrine concentration was determined by a specific bio-assay method with the rat uterus. A significant increase in excretion of these amines was found by both methods; a more marked increase was noted for epinephrine. It was concluded that the secretion of these amines is involved in the chemical control of heat production during exposure to cold. Submitted on July 6, 1959
Preservation of viable bone marrow cells by freezing
Authors: Bender M. A. , Tran Phan The , Smith L. H. 
Published: December 2017

In a study of low-temperature preservation, mouse bone marrow cells were slow-frozen and fast-thawed. A number of additives, including glycerol and other polyhydric alcohols, were tested for their ability to protect the cells against freezing and thawing damage. Effectiveness of thawed cells to promote recovery in lethally irradiated (900 r) mice was used as a measure of viability. Tyrode's solution, mouse serum, glucose, polyvinylpyrrolidone, dextran and bovine serum albumin gave little or no protection at the concentrations tested. Polyhydric alcohols and some sugars and other organic compounds were effective at certain concentrations. Results of tests of marrow frozen in 15% glycerol made after storage at various temperatures for various times indicate that liquid nitrogen temperatures give the best long-term storage. The eosin uptake test was found to be a poor assay of the effectiveness of thawed marrow samples. Submitted on November 13, 1959
Central and peripheral control mechanisms of shivering and its effects on respiration
Authors: Lim Thomas P. K. 
Published: December 2017

Central and peripheral contributions to the initiation of shivering have been studied in anesthetized dogs employing a thermal dissociation technique. Shivering was elicited invariably during differential cooling of the head or the trunk alone as well as in the course of whole-body cooling. Either ‘peripheral’ or ‘central shivering’ could be produced repeatedly and also inhibited by elevation of subcutaneous temperature in central shivering or brain temperature in peripheral shivering. In part 2 of this study, respiratory effects of shivering have been assessed during the steady state of hypothermia in the anesthetized animal. During shivering, O2 intake and CO2 output were doubled or tripled but the respiratory exchange ratio remained essentially unchanged. Total ventilation increased linearly with metabolic rate and yet arterial pH, pCO2 and buffer base revealed no significant changes with or without shivering. Although alveolar ventilation was increased almost three times, no marked alterations occurred in physiological dead space. Moderate hemoconcentration and a consistent elevation of pulse pressure were seen during shivering. Submitted on October 11, 1959
Thermal and metabolic responses of Arctic Indians to moderate cold exposure at the end of winter
Authors: Elsner Robert W. , Andersen K. Lange , Hermansen Lars 
Published: December 2017

Oxygen consumption, skin temperature and rectal temperature during nights of cold exposure were measured in eight Indian men from a remote arctic village who had been similarly studied the previous fall. The metabolic response of the Indians to cold exposure was similar in the spring to that observed in the fall studies. All subjects showed a general increase of about 30% in O2 consumption during the night. In addition, the basal metabolic rate of four subjects measured was slightly above the DuBois standards, as in the fall. A decline in rectal and skin temperatures throughout the night was observed to be similar to that of the same subjects in the fall, with the exception that the surface temperatures of arms and legs were slightly cooler in the spring. It was concluded that, except for a tendency toward heat conservation by cooling of extremities, no metabolic or thermal changes of a seasonal nature had taken place in these subjects during the arctic winter. Submitted on November 12, 1959
Responses of Bushmen and Europeans on exposure to winter night temperatures in the Kalahari
Authors: Ward Joan S. , Bredell G. A. C. , Wenzel H. G. 
Published: December 2017

Eight Bushmen and five Europeans were exposed during winter nights in the Kalahari desert to temperatures ranging from about 27°C to 2°C. Oxygen consumption and skin and rectal temperatures were measured over the period of 1frac12–2 hours of exposure. Comparison of increased metabolic rate with decreasing air temperatures measured in this study is made with similar data on young Norwegians. Bushmen and Europeans respond in a similar manner metabolically to the degree of cold stress experienced. Skin temperatures of the former tend to be lower and metabolism greater than in Europeans. The lower metabolic rate of Europeans is concluded to be due to the greater insulation afforded by their considerably larger subcutaneous fat deposits. These findings on the cold response of Bushmen contrast with those on Australian aborigines in comparable environmental conditions. Submitted on January 4, 1960
Some membrane properties of the effector in the galvanic skin response
Authors: Edelberg Robert , Greiner Theodore , Burch Neil R. 
Published: December 2017

Several membrane-like properties of the effector in the galvanic skin response (GSR) have been measured in humans by comparison of activity at a control site with that of a site subjected to changes of external chemical environment or changes in direction or density of imposed current. Comparison of inorganic chlorides shows that small cations, e.g. K+, may reversibly reduce GSR amplitude and R by 40%; larger cations, e.g. Ca++, increase GSR by several hundred per cent, while at the same time reducing basal resistance (R). GSR and R are reduced by acids and alkalies and by detergents. The effector is a poor rectifier, but there is a pronounced effect of polarity of current on the amplitude of the GSR in the case of large cations or anions combined with smaller ions of opposite charge. Current densities beyond 11 μamp/cm2 produce an ‘injury’ effect manifested in GSR and apparent resistance. These results have been interpreted in terms of an active superficial membrane having a relatively low charge. Submitted on August 3, 1959
Use of clothing records to demonstrate acclimatization to cold in man
Authors: Goldsmith R. 
Published: December 2017

Eight men lived for a year under considerable cold stress, doing hard physical outdoor work for much of the time. Observations of clothing worn and records of comfort vote were made, together with records of environmental conditions. There was a reduction in the number of layers of clothes worn in the last quarter of the period as compared with the first. A comparison between days of equal windchill in the first and second half of the period also showed significant reduction in the clothing assemblies. It is concluded that during a period of prolonged cold stress men do acclimatize to the cold, and this is manifested by a voluntary reduction in the amount of clothing they wear. Submitted on October 29, 1959
Lung volume, alveolar ventilation and perfusion interrelationships in chronic pulmonary emphysema
Authors: Briscoe W. A. , Cree E. M. , Filler J. , Houssay H. E. J. , Cournand A. 
Published: December 2017

In 10 patients with chronic pulmonary emphysema the distribution of ventilation within the lungs was assessed by a nitrogen washout and washin technique. Alveolar ventilation per minute per unit lung volume had a mean value of 5.0 in well ventilated alveoli and 0.19, or 1/26 as much, in poorly ventilated alveoli. Distribution of blood perfusion was estimated by a new method from these data and from O2 consumption and arterial O2 saturation. On the average, poorly ventilated alveoli which constituted 66% of lung volume were perfused by not more than 52% of the cardiac output. Thus poorly ventilated alveoli were underperfused by blood. Ventilation/perfusion ratios averaged 2.24 in well ventilated alveoli and 0.23 in poorly ventilated alveoli. Oxygen saturation averaged 85% in arterial blood and 97frac12% and 76%, respectively, in end-capillary blood leaving well and poorly ventilated alveoli. Inhomogeneity of this degree within the lung invalidates calculations of diffusing capacity based on any single mean PaOO2 and of alveolar ventilation based on identification of mean alveolar Pco2 with arterial blood Pco2. Submitted on March 25, 1960
Unanesthetized dogs with increased respiratory dead space
Authors: Barnett Thomas B. , Peters Richard M. 
Published: December 2017

A method is described for maintaining a permanent tracheostomy in dogs. This animal preparation has been used to study the effects of artificially increased respiratory dead space. Trained dogs with tracheostomies have made possible measurements of ventilation without anesthesia. It has been found that additions to the respiratory dead space in the form of tubing of frac34 in. i.d. result in an increase in physiologic dead space of the same magnitude as the volume of tubing added. Increasing the dead space in this manner resulted in an increased minute volume which was accomplished principally by an increase in tidal volume without a significant or consistent change in respiratory rate. Alveolar ventilation remained unchanged even with large additions to the dead space (20–30 cc/kg of animal wt.). Arterial pCO2 was significantly higher in these animals than in the controls. The CO2 tension was similarly elevated when extra dead space of lesser volume (5–20 cc/kg) was allowed to remain on the dogs for more than 48 hours. Submitted on April 13, 1960
Cardiogenic oscillations in expired nitrogen and regional alveolar hypoventilation
Authors: Langer Glenn A. , Bornstein Donald L. , Fishman Alfred P. 
Published: December 2017

The plateau of the single-breath nitrogen curve shows rhythmic oscillations in the concentration of nitrogen. In the present study, the mechanisms involved in the genesis of these oscillations were investigated by varying the composition of the inspired gases and by different respiratory maneuvers. The oscillations were shown to be altered in a characteristic and predictable way in subjects with particular diseases of the heart and lungs. The conclusion is reached that these oscillations represent a combination of uneven alveolar ventilation and vascular impacts; however, the ‘poorly ventilated’ areas are thought to be located in the parahilar, rather than in the peripheral, regions of the lung. Submitted on January 4, 1960
Respiratory sinus arrhythmia: laws derived from computer simulation
Authors: Clynes Manfred 
Published: December 2017

Dynamic mathematical relations describing respiratory sinus arrhythmia were derived through analogue computer simulation. If a signal proportional to thorax circumference is fed into the analogue computer, it calculates with differential equations the complex heart rate changes in real time and records them along with those of the real heart. Close correspondence of the predicted and actual changes of heart rate for a wide variety of modes of breathing, and for different individuals, proves the validity of the nonlinear differential equations describing the phenomenon. The respiratory effects are shown to be caused by two separate reflexes each producing biphasic heart rate transients in the same directions. The observed effects are the result of superposition of those transients. Previous paradoxical results in attempting to relate heart rate to respiration on a steady-state, nondynamic basis are thus explained. The laws indicate that stretch receptors and not hemodynamic or central nervous factors initiate the changes in heart rate. The analysis also allows heart rate effects of exercise and emotional stresses to be more precisely perceived, as clearly separated from respiratory effects. Submitted on June 16, 1959
Effect of nutrient supplements during work on performance capacity in dogs
Authors: Young D. R. , Schafer N. S. , Price R. 
Published: December 2017

The effect of consuming fluid supplements during work on maximum performance capacity has been examined in the dog. Within the range of 0–1.6 1. of water, maximum work energy expenditure was a positive function of the fluid intake. Intake of water in excess of 2 l. did not further increase work capability. Additional tests were undertaken to study the effect of nutrient supplementation during work on performance capacity. Whole milk with added copper and iron was used as the control to study the comparative effect on performance of providing either no supplement, water, or separately pure solutions of lactalbumin, glucose, phospholipids, or water-soluble vitamins (exclusive of ascorbic acid. Consumption of milk, vitamins, and phospholipids led to a significant reduction (–54%) in work capability. The intake of glucose or protein was neither beneficial nor detrimental. The cardiorespiratory responses and blood chemistry changes were for the most part unrelated to variations in performance. Submitted on July 5, 1960
Physiology and morphology of blood coagulation in polycythemia vera
Authors: James Thomas N. , Johnson Shirley A. , Monto Raymond W. 
Published: December 2017

The observation that red cells fall out of the clotted blood in polycythemia vera has been documented previously. This phenomenon appears in all patients with initial thrombocytosis but continues to occur even when the red cell mass and platelet numbers come under control. The only known coagulation defect is a pronounced reduction of platelet factor 3 in the platelets. In this investigation, platelet-plasma clots from normal individuals and polycythemia vera patients were sectioned and stained at various intervals during coagulation and clot retraction. Great disorganization of the platelet-fibrin network was observed in the polycythemia vera clots when compared with the normal clots, and it was apparent that the red cells could easily slip through the openings in the network. Submitted on July 11, 1960