bluuebunny/crossref_metadata_2025_split huggingface dataset:
Specificity of H ion concentration as a carotid chemoreceptor stimulus
Authors: Hornbein Thomas F. , Roos Albert 
Published: December 2017

The present study was designed to separate quantitatively the relative contributions of (H+) and Pco2 as chemoreceptor stimuli. The integrated electrical activity from the entire Hering's nerve of the cat was measured and correlated with values of (H+), Pco2, and Po2 of arterial blood. By utilizing a combination of respiratory and metabolic acidosis or alkalosis, the effect of (H+) on carotid body nerve activity could be separated from that of Pco2. Most studies were performed at high Po2, a few against a changing hypoxic background. The results indicate: 1) the pre-eminence of (H+) as a chemoreceptor stimulus, CO2 acting only by virtue of its effect in altering (H+); 2) the relationship between (H+) or Pco2 and chemoreceptor activity is nonlinear; 3) the potentiation between hypoxia and hypercapnia at the chemoreceptor level is due primarily to interaction between low oxygen tension and increased (H+), independent of Pco2. The significance of these findings to the exchange of CO2 and of (H+) and (HCO3-) ions between the intracellular and extracellular milieu of the carotid chemoreceptor cells is discussed. Submitted on September 28, 1962
Reversible cooling of cerebellum in awake, unrestrained rats
Authors: Manni Ermanno , Mills Laurence W. , Dow Robert S. 
Published: December 2017

A method has been developed for producing reversible cooling of the cerebellum in awake, unrestrained rats. A technique is described for covering the cerebellar cortex with a piece of thin platinum foil. Cooling of the cerebellum in the awake animal was accomplished by placing granules of dry ice in contact with the foil. After the effects of cerebellar cooling had been observed repeatedly in the awake, unanesthetized animals, the rats were once again anesthetized in order that subcortical temperature changes could be measured. The magnitude of the temperature changes was correlated with distance from the foil. The temperature of subcortical cerebellar tissue 2–6 mm below the platinum foil dropped 10 C in 4–5 min after application of the dry ice. Submitted on August 8, 1962
Blood lactates after prolonged severe exercise
Authors: Åstrand Per-Olof , Hallbäck Inger , Hedman Rune , Saltin Bengt 
Published: December 2017

Blood was drawn from cross-country skiers at 1–3 min after the finish in competitions on distances from 10 to 85 km and the blood lactate determined. Despite a maximal effort of the skiers, accentuated at the end of the race, there was a successive decrease in the blood lactate concentration with work time. After a 10-km race, work time 35–36 min, the average was 139 mg/100 ml of blood (12.5 mEq/liter); after a 30-km race, with a time of 1 hr 50 min-1 hr 56 min, the mean value was 68 mg/100 ml (6.1 mEq/liter); and after a 50-km race, work time 3 hr 6 min-3 hr 18 min, 39 mg/100 ml (3.5 mEq/liter). A lactate concentration exceeding 100 mg/100 ml is a common finding after maximal muscular exercise involving large muscles. The explanation for the low values after prolonged maximal work, indicating a different kind of fatigue, is presently obscure. Data are presented on the oxygen uptake attained during skiing at actual racing speed (average Vo2 = 4.45 liters/min). Submitted on July 16, 1962
Tissue studies during recovery from immobilization atrophy
Authors: Eichelberger Lillian , Roma Michael , Moulder Peter V. 
Published: December 2017

Immobilization of one hind leg of puppies was produced at 12 weeks of age. After 6 weeks of immobilization, the immobilized muscles were restored to weight bearing. The opposite leg was the control leg. To study recovery from atrophy in these muscles, biochemical analyses and histochemical patterns of the muscles were used. Recovery periods varied from 55 to 300 days. In the 91-day remobilization group there were increased values in the interfiber constituents as well as decreases in the intrafiber constituents, but values were not as large as in immobilization only. After 300 days of remobilization the formerly atrophic muscles had regained the same concentration as in the control muscles, indicating recovery. The histochemical patterns of 1 kg of control muscle and remobilized muscle were traced. The ultrafiltrate volume in the groups up to 91 days of remobilization was increased in amounts over the control volumes, but the increases were not as large as in immobilization only. In 300-day group all volumes were the same as in the control, indicating recovery from atrophy, according to these criteria. Submitted on November 12, 1962
Pulmonary diffusing capacity of athletes
Authors: Mostyn E. M. , Helle S. , Gee J. B. L. , Bentivoglio L. G. , Bates D. V. 
Published: December 2017

Champion swimmers have been found to have significantly higher steady-state pulmonary diffusing capacities than those measured in normal subjects of comparable age at the same exercise level. Nonactive and moderately active normal subjects, swimmers of average ability, long distance runners, and older ex-athletes were found to show no significant deviation from predicted values of DlCO, either in absolute terms or in relation to body surface area or lung midcapacity. The high DlCO in champion swimmers results from a larger than normal pulmonary capillary blood volume (Vc). It has been observed that normal subjects can increase the measured steady-state Dl during exercise by a “held inspiration“ maneuver, but this increase is caused by an increased membrane diffusion component (Dm) per liter midcapacity and not by an increased Vc. Champion swimmers have a particular need of a high Dl since they must be able to transfer large volumes of oxygen across the lung when the alveolar pO2 has fallen to low levels. Submitted on August 20, 1962
Cerebrospinal fluid acid-base balance during a changing ventilatory state in man
Authors: Fisher Vincent J. , Christianson Lynn C. 
Published: December 2017

Comparison of the rate and magnitude of changes in pH, CO2 tension, and bicarbonate concentration in arterial blood, cisternal spinal fluid, and lumbar spinal fluid was made in man during hyperventilation and recovery. CO2 tension changes in cisternal fluid were rapid and significant, although less in magnitude than those in arterial blood, whereas changes in lumbar fluid CO2 tension were minimal and slow, lagging behind cisternal changes by 10–20 min. The different rates of change following altered ventilation explain some of the reported reversals of the normal lumbar spinal fluid to arterial blood CO2 tension gradients. It also suggests that the choroid plexus is one site of removal of CO2 from spinal fluid. Submitted on December 13, 1962
Metabolic and thermal responses to muscular exertion in the cold
Authors: Str⊘mme S. , Andersen K. Lange , Elsner R. W. 
Published: December 2017

The metabolic and thermal responses to muscular exertion in the cold were studied in outdoor and indoor workers. The metabolic rate during exercise was the same in the cold as in a thermally neutral (warm) environment when workload was sufficiently high to prevent a fall in the rectal temperature. At lower levels of work the metabolic rate in the cold was higher than that in the warm. No significant differences in the work metabolism were found between the groups. When the resting subjects were exposed to the cold environment prior to the exercise the skin temperature decreased. The rate of decrease diminished as exercise progressed and at higher load of work the extra heat generated in the body was enough to rewarm the skin, even on the most peripheral parts. The rate of decrease of skin surface cooling during rest in the cold was found to be slower in the outdoor workers than in the indoor workers, and the onset of the rewarming occurred much quicker in the former. These differences in skin temperature between outdoor and indoor workers indicate an acclimation to cold affecting the vasomotor control of the skin circulation. The hypothesis is suggested that habituation to cold leads to a lower set point of the thermosensitive cells in the thermoregulating center, so that vasodilatation impulses are discharged at a lower temperature. Submitted on September 17, 1962
Early changes in serum enzymes in the rat following burn trauma
Authors: Spector Arthur A. , Pauli Wayne A. 
Published: December 2017

Under ether anesthesia, 30% surface area scalds were administered to young adult rats. Controls were treated similarly except for the scald. The animals were sacrificed at 15 min after injury, and their serum was analyzed for enzyme activities and chemical constituents. Large increases in catalase, glucose 6-phosphate dehydrogenase, lactic dehydrogenase, glutamic-oxalacetic transaminase, and glutamic-pyruvic transaminase activites were noted in postburn serum. No statistically significant change was found in acetylcholinesterase, acid phosphatase, alkaline phosphatase, leucine aminopeptidase, 5'-nucleotidase, or succinic dehydrogenase. Amylase activity was decreased in the burned animals. Serum oxyhemoglobin and inorganic phosphate were elevated, but total protein remained unchanged following trauma. The etiology of the early postburn serum changes is believed to be tissue damage produced by the burn, an important component of which is in vivo hemolysis. A possible relationship between the rapid extracellular buildup of enzymatically active protein and the pathology of burn injury is suggested. Submitted on November 15, 1962
Metabolism of Sr58 and Ca45 in man after single and multiple doses
Authors: Samachson Joseph 
Published: December 2017

Three patients received single doses of Sr85 and one Ca45 as well, the plasma levels, and urinary and fecal excretions being followed for 3–4 weeks. Calculations were then made to predict plasma levels and excretions following the administration of 12 small doses to each patient, and values predicted were compared with those found. Changes in calcium metabolism limited the predictive value of single-dose data, but when variations in urinary calcium could be allowed for, predicted and found values agreed well. The factors involved in extrapolation from single to multiple doses are discussed. Within certain limitations, the extrapolation appears valid and may be applicable to the problems involved in the investigation of Sr90 as well, although the fact that the latter is ingested over long periods of time makes comparison with single-dose data more hazardous. Submitted on December 21, 1962
Cardiac monitoring and telemetering system
Authors: Furman K. I. , Lupu N. Z. 
Published: December 2017

In this system an audio-frequency subcarrier is modulated (FM) by the amplified ECG signal from a test subject. The FM tone produced is transmitted to the stable sections consisting of a receiver, audio-frequency discriminator, and recording apparatus. The apparatus can be used in conjunction with a conventional short-wave radio receiver, and if necessary a conventional tape recorder. The use of an audio-frequency subcarrier enables simple aural monitoring of the heart rate to be made either directly from the apparatus on the subject or after transmission. The ECG is monitored directly from the discriminator output. Submitted on November 29, 1962
Measurement of oxygen tensions in cerebral tissues of rats exposed to high pressures of oxygen
Authors: Jamieson Dana , Van Den Brenk H. A. S. 
Published: December 2017

Brain and cerebrospinal oxygen tensions have been measured in rats breathing air or in various high pressures of oxygen (OHP). Addition of 5% CO2 to the inspired oxygen raised cerebral oxygen tensions when rats were exposed to 2 atm abs or above. Inhibition of 75% hemoglobin saturation by para-aminopropriophenone lowered cerebral pO2 in rats breathing air, but not in rats exposed to OHP. The rate of rise of cerebral pO2 to a steady level after rapid compression was found to be faster than the rate of fall to a steady level following decompression. Addition of CO2 to the inspired gas mixture increased the rate of rise of cerebral pO2. The anesthetics urethane and pentobarbital sodium did not affect cerebral pO2 in rats breathing air or oxygen at 4 atm. The results are discussed in relation to factors contributing to oxygen poisoning at high pressures. Submitted on October 30, 1962
Effect of vagotomy and vagal stimulation on lung mechanics and circulation
Authors: Colebatch H. J. H. , Halmagyi D. F. J. 
Published: December 2017

In sheep, anesthetized and intubated, bilateral cervical vagotomy produced no change in lung compliance (Cl), reduced inspiratory resistance to airflow, increased expiratory resistance to airflow, and changed the pattern of breathing. Electrical stimulation of the peripheral end of the cut vagus nerve produced an immediate increase in lung volume due to an increase in inspiratory tonus, a fall in Cl, an increase in resistance to airflow, and a decrease in heart rate and systemic arterial pressure. Pulmonary arterial pressure remained unchanged; pulmonary arterial resistance increased. These effects were blocked by atropine. The lung mechanics changes were partly reversed spontaneously, completely reversed by forced inflation, and potentiated by prostigmine. The effects on lung mechanics suggest that vagal stimulation in the sheep mainly affects the peripheral airways producing airway closure, and indicates the possibility of a nervous mechanism for the control of the number of ventilated lung units. compliance; total pulmonary resistance; inspiratory; tonus; peripheral airway reaction; respiratory pattern Submitted on December 6, 1962
Effect of different pressure breathing patterns on alveolar-arterial gradients in dogs
Authors: Bergman Norman A. 
Published: December 2017

Arterial end-tidal carbon dioxide gradients were measured and alveolar-arterial oxygen gradients were estimated in dogs during intermittent positive pressure ventilation at constant inflating pressure using four curves having differing pressure profiles. The smallest gradients for both oxygen and carbon dioxide occurred when mean pressure during respiratory cycles was high and decreases in mean pressure were consistently associated with increases in both oxygen and carbon dioxide gradients. Profile of the applied pressure curve per se did not influence magnitude of the gradients. It is concluded that during intermittent positive pressure breathing, relative distribution of pulmonary capillary blood flow and inspired gas may vary with mean pressure during the respiratory cycle and is more uniform when mean pressure during the respiratory cycle is high. artificial ventilation; intermittent positive pressure breathing; alveolar-arterial; carbon dioxide gradient; distribution of inspired gas; pulmonary capillary blood flow Submitted on December 13, 1962
Effect of pulmonary vascular engorgement on Dl during and immediately after exercise
Authors: Krumholz Richard A. , King Leroy H. , Ross Joseph C. 
Published: December 2017

Pulmonary diffusing capacity (Dl) is increased more markedly by moderate exercise, which causes little increase in pulmonary vascular pressure, than by inflation of a pressure suit over the lower part of the body, which produces pulmonary vascular engorgement and marked increases in pulmonary pressure. This study was designed to determine whether exercise causes the pulmonary capillary bed to be more permissive to passive dilatation. Dl was determined in 12 subjects before, during, and soon after a period of exercise with and without the pressure suit inflated. Dl was increased in resting subjects by suit inflation, but less than with exercise. Exercise with suit inflation did not increase Dl more than exercise alone. Suit inflation 3 min after exercise ended, however, increased Dl to higher levels than at any other time with suit inflation alone. The pulmonary capillary bed apparently cannot be further dilated by vascular engorgement during exercise beyond that caused by exercise alone. Also, soon after exercise ends, the pulmonary capillary bed is more permissive to passive dilatation by vascular engorgement with suit inflation. pulmonary diffusing capacity; pulmonary capillary bed; human male Submitted on June 17, 1963
Tolerance to extreme cold at altitude in a Nepalese pilgrim
Authors: Pugh L. G. C. E. 
Published: December 2017

Body temperature and respiratory experiments are reported on a Nepalese pilgrim who survived, uninjured, 4 days of exposure at 15,000–17,500 ft in midwinter, wearing only light clothing and no shoes or gloves. His resistance to cold depended on elevation of metabolism and, unlike tolerance of immersion in cold water, was not related to subcutaneous fat thickness. He slept soundly in spite of the cold and so did not become exhausted. In 3–4-hr experiments at o C (clothed), rectal temperature and skin temperature over the trunk showed only minor changes; hand and foot temperatures did not fall below 10–13 C. Maintenance of body temperature was accounted for by elevation of metabolism. survival in cold Submitted on February 19, 1963
Interaction of paired sensory stimuli and conduction in peripheral nerves
Authors: Békésy G. Von 
Published: December 2017

It is well known from directional hearing that a sound source is localized in the middle plane when the sound reaches both ears simultaneously. If there is a time difference between the sound's arrival at the two ears, the sound source is localized to one or the other side, depending on which side receives it first. A time difference as small as 1 msec is enough to produce full lateralization. Thus the shift in the localization of a sensation can be used to measure small time intervals. This shift in localization appears to be not a specific ability of the ear, but a general quality of many sense organs with large surfaces. Even in the sense of taste, the position of the sensation on the tongue changes when the time difference between two separately placed stimuli is altered. If the time delay is used to estimate the speed of conduction for different sensations such as touch, warmth, electrical stimulation, and taste, the resulting estimates are greatly in excess of the values obtained by direct measurements as reported in the literature. brain sensory nerve fiber connections between hemispheres; directional hearing; inhibition in sense organs; taste localization; vibratory localization Submitted on March 29, 1963
In vitro assessment of cell viability in human bone marrow preserved at -79 C
Authors: Pegg D. E. 
Published: December 2017

Human bone marrow was stored at -79 C for 1 hr with glycerol, with dimethyl sulfoxide, or without any protective agent, both after rapid cooling and after slow cooling. Each sample was subjected to four viability tests, and observations were also made on samples stored for 1 hr at room temperature. By comparison with the established effects of these preservation procedures on the radiation recovery factor, it is concluded that: 1) the dye exclusion test using trypan blue is a poor indicator of viability after freezing; 2) the measurement of deoxyribonucleic acid synthesis gives results which correlate well with in vivo assays; 3) the detection of motility is the only in vitro test to provide unequivocal evidence of life, but is not susceptible to quantitative measurement: slow cooling in the presence of glycerol or dimethyl sulfoxide was the most successful preservation procedure used; 4) supravital staining with acridine orange, although it is a purely empirical test, gives a good correlation with the results of in vivo assay and is simple, convenient, and rapid to perform. cellular viability tests; radiation protective cells; radiation recovery factor; cell survival after freezing; glycerol and dimethyl sulfoxide additives in tissue preservation; slow cooling versus rapid cooling in tissue preservation; trypan blue nuclear staining, DNA synthesis, mobility, and supravital staining as viability tests; bone marrow storage viability tests; glycerol and dimethyl sulfoxide in tissue preservation; low temperature cell preservation Submitted on May 20, 1963
Human urinary catecholamines in relation to climate
Authors: Feller Ralph P. , Hale Henry B. 
Published: December 2017

Urinary catecholamine determinations were employed to appraise human sympathoadrenal activity in different seasons (autumn, winter, and spring), the study being made in a subtropical climate, where maximum temperature in these seasons averaged, respectively, 66, 60, and 74 F. Two hundred and thirty-one healthy men were studied under standardized laboratory conditions, and significant variation with season (P < .01) was established for excretion of both epinephrine and norepinephrine and for the norepinephrine-to-epinephrine ratio, the latter index providing the most clear-cut pattern of variation with season, and suggesting greater activity in the sympathoadrenal system in winter than in autumn, with reversal in spring. Cigarette smoking and anxiety, acting singly or jointly, had modifying effects on climate-induced changes in epinephrine excretion. chronic cold effects in man; bioclimatology; seasonal sympathoadrenal activity; epinephrine and norepinephrine excretion in chronic cold; smoking and epinephrine excretion; anxiety and epinephrine excretion Submitted on May 13, 1963
Catecholamine excretion in smokers and nonsmokers
Authors: Westfall Thomas C. , Watts Daniel T. 
Published: December 2017

The 24-hr urinary excretion of epinephrine and norepinephrine in nonsmokers was compared to that of a group of heavy smokers using a fluorometric technique. The 24-hr epinephrine excretion in nonsmokers was 6.5 ± 0.8 μg/24 hr; whereas the excretion in smokers was 12.1 ± 0.9 μg/24 hr, a statistically significant difference. There was no significant difference in the norepinephrine output between the two groups. The excretion of epinephrine and norepinephrine was also determined at 30-min intervals before, during, and following heavy smoking in 15 subjects who normally smoked. The results indicate that the epinephrine and total catecholamine excretion levels increase significantly above control levels during periods of heavy smoking. Studies were also done on the effect of smoking one cigarette on the plasma epinephrine levels in three patients undergoing cardiac catherization. Samples were obtained from the inferior vena cava above and below the inflow from the adrenals. Results show that the epinephrine levels were slightly higher in the inferior vena cava above the adrenal inflow during and immediately following cigarette smoking in all three patients. epinephrine; norepinephrine; nicotine; sympathoadrenal stimulation Submitted on June 17, 1963