bluuebunny/crossref_metadata_2025 huggingface dataset:
Cutaneous vascular responses in finger and forearm during rising ambient temperatures
Authors: Senay L. C. , Christensen M. , Hertzman A. B.
Published: December 2017

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

Submitted on January 18, 1960
Application of gas chromatography to respiratory gas analysis
Authors: Hamilton Lyle H. , Kory Ross C.
Published: December 2017

Analyses of respiratory gases for CO2 and O2 can be performed on a single sample with the Fisher model 25 gas partitioner. By modifying the instrument and adding a Wilkens gas-sampling valve and a zero-suppression selector to the system, we have been able to achieve analytical accuracy comparable to that for the Scholander micrometer gas analyzer. The zero-suppression selector was considered to be essential for achieving maximum accuracy with peak height measurements. With this system, the standard deviation for its accuracy was ±0.024 vol. % for o2 and approximately ±0.002 vol. % for CO2 in respiratory gas samples. Empirical equations were developed to correct for argon interference in O2 determinations. Gas chromatography offers a unique advantage which is not shared by other instruments. It provides a single analytical technique for the simple and accurate analysis of a wide spectrum of gases useful in studies of respiratory physiology and pathology.

Submitted on April 4, 1960
A re-evaluation of effects of acute central congestion on pulmonary compliance in normal subjects
Authors: Bondurant Stuart , Mead Jere , Cook C. D.
Published: December 2017

In a re-examination of the effects on lung compliance of acute central vascular engorgement produced in normal subjects by inflation of a ‘G suit’ it was found that the reduction in complicance, previously reported, during suit inflation was in part due to artifactual changes in esophageal pressure. When the esophageal balloon used for pressure recording was positioned higher on the esophagus than in the previous study, and when decreases in mid-position, which usually accompany the abdominal compression associated with suit inflation, were prevented, the complicance reductions in a small group of subjects were approximately one-half as great as those obtained with the balloon low in the esophagus and with the mid-position uncontrolled. Extrinsic pressures from distended mediastinal structures, greater in the distal esophagus, and greater at low lung volumes are thought to be responsible. Additional observations are presented which support this possibility. It is concluded that respiratory esophageal pressure change may not be a valid index of lung surface pressure change in the presence of central vascular congestion. Those measurements of pulmonary compliance during clinical and experimental central vascular engorgement which have used esophageal pressure must be accepted with this reservation.

Submitted on March 18, 1960
Gastric osmolar clearance and ionic barter: two mechanisms of electrolyte secretion by the human stomach
Authors: Hirschowitz Basil I.
Published: December 2017

Measurements of gastric juice volume (V) and H ion (H), chloride ion (ClG), Na ion (NaG) concentrations and of osmolality (OG) as well as plasma sodium (NaP) and osmolality (OP) were made in nine men before and after a subcutaneous injection of histamine. The gastric osmolar clearance (GOC) was calculated from the formula (V·OG)/OP and this correlated well with both acid and chloride output. The theoretical clearance of sodium (TCNa) was calculated for each specimen by the formula (V·OG·NaP)/OP, and this equaled the output of acid plus sodium in the gastric juice V(H + NaG). The mol-mol relationship furthermore suggests that the gastric acid is secreted on a 1:1 basis in exchange for Na ions theoretically cleared within the framework of a gastric osmolar clearance mechanism. It also explains why, even under the most optimal conditions in man, the maximum value for H+ concentration does not exceed 150 mEq/l. On the basis of these observations it is suggested that the various theories which propose a primary acid secretion of 167, 169, 208 or 464 mn, respectively, are unlikely.

Submitted on January 22, 1960
Fraction of maximum breathing capacity available for prolonged hyperventilation
Authors: Zocche Gian Paolo , Fritts Harry W. , Cournand Andre
Published: December 2017

The volume of ventilation which nine healthy young men could maintain for 15 minutes was only 53% of the maximum breathing capacity (MBC). A similar figure was obtained for older patients with chronic pulmonary emphysema. These data suggest that the MBC is not the limiting response to be expected from stimuli such as hypoxia or hypercapnia, and that the capacity of a patient for maintaining an augmented minute volume is an important determinant of the responses these stimuli evoke.

Submitted on May 27, 1960
Ventilation of lungs in infant and adult rats and its responses to hypoxia
Authors: Adolph E. F. , Hoy P. A.
Published: December 2017

Do the controls of breathing differ with age? Pulmonary ventilation was measured by body plethysmograph and pressure transducer. After birth, breathing was irregular (pneumotaxic); steadiness from breath to breath was gained at 3 days; extraction of oxygen from the inspired air became more uniform after 10 days. In pO2 20–40 mm Hg only infants survived a half hour; ventilation did not usually increase, and often decreased. Hyperventilation even in 40 mm Hg was not sustained for many minutes in the newborn, but by 6 days was large and enduring. Heartbeats decreased in frequency during severe hypoxia. Oxygen consumption decreased 75% during hypoxia that allowed survival of infants; it sometimes recovered only slowly after hypoxia ended. Tolerance of infants to low oxygen thus consisted in ability to utilize some oxygen at low pressures and to dispense with some oxygen. Some factor other than pCO2 or pO2, possibly centrogenic, often controlled ventilation in infancy. Low oxygen maximally accelerated the breathing at an age when endurance of hypoxia remained.

Submitted on May 12, 1960
Transient effect of sudden mild hypoxia on respiration
Authors: Hornbein Thomas F. , Roos Albert , Griffo Zora J.
Published: December 2017

Recent studies of carotid body chemoreceptor activity in cats show that the activity of these organs increases markedly over a range of alveolar pO2 considerably higher than the alveolar pO2 of 50–60 mm Hg known to produce an increase in ventilation in the steady state. In an attempt to explain this discrepancy between chemoreceptor activity and ventilation, the transient ventilatory response to two breaths of a low O2 mixture was observed and correlated with the alveolar pO2 during this brief hypoxic stimulus. A transient increase in ventilation could be detected at an alveolar pO2 of 93 mm Hg, that is, considerably higher than the highest pO2 known to increase ventilation during the steady state. These findings are interpreted as evidence of an increased chemoreceptor drive when alveolar O2 tension is lowered only slightly below that existing at sea level. Possible reasons for the difference between the steady state and transient responses are discussed.

Submitted on June 6, 1960
Some factors modifying the expression of human strength
Authors: Ikai Michio , Steinhaus Arthur H
Published: December 2017

The maximal pull of forearm flexors was increased and, in some instances, decreased in predictable fashion by a loud noise, by the subject's own outcry, by certain pharmacologic agents (alcohol, adrenaline, and amphetamine), and by hypnosis. Significant average changes ranging from +26.5% to –31% were observed. An analysis of these data and that of others leads us to regard all performances short of the maximum limit, which is always imposed by the structure and prevailing physiologic state of the performing muscles, to be manifestations of acquired inhibitions that in turn are subject to disinhibition by pure Pavlovian procedures, by anesthetization of inhibitory mechanisms, or by pharmacologically induced symptoms serving as stimuli for disinhibition.

Submitted on June 20, 1960
Effect of training on physical fitness of women students
Authors: Sloan A. W.
Published: December 2017

To ascertain the effect of physical training on young women, four groups were subjected to a modified Harvard step test at the beginning of the academic year and again 4 and 9 months later. One group, specializing in physical education, had a very active program of gymnastics, dancing and games; two other groups had a much less active program; a fourth group had no physical training at all. In the series as a whole there was no correlation between fitness index and either height or weight and no evidence that menstruation influenced performance of the test. At the beginning of the investigation the physical education students had higher fitness indexes than the others and they improved with training. Lesser degrees of physical training caused no significant increase in fitness index but counteracted a tendency to deterioration observed in the group that had no physical training. Changes in the resting pulse were less consistent, and resting pulse rates showed little correlation with fitness indexes.

Submitted on June 1, 1960
Unilateral hypoventilation produced in dogs by occluding one pulmonary artery
Authors: Severinghaus John W. , Swenson Edward W. , Finley Theodore N. , Lategola Michael T. , Williams Jack
Published: December 2017

Temporary unilateral pulmonary artery occlusion resulted within 1 minute in a shift of tidal volume away from unperfused lungs in 14 anesthetized closed-chest dogs. The shift of ventilation was caused by bronchoconstriction following the decrease of CO2 on the occluded side. It was prevented by inhalation into that side of 6% CO2 in air, isoproterenol aerosol or 100% N2, but not by atropine or vagotomy. Airway resistance on the occluded side was doubled, and compliance fell 25%. Functional residual capacity fell variably (0–25%), and anatomic dead space decreased. When blood flow was restored, shunting was detected and ventilation returned slowly with normal inflation or immediately after hyperinflation of that lung. This suggests that terminal and respiratory bronchiolar smooth muscle constriction may lead to airway closure and atelectasis and that the gas exchange of the smooth muscle in smaller airways is carried out by direct diffusion to and from the airway rather than with blood.

Submitted on June 9, 1960
Circulatory response to ventilatory obstruction during steady-state exercise
Authors: Levy A. M. , Hanson J. S. , Tabakin B. S.
Published: December 2017

The effects of expiratory airway obstruction on cardiac output during treadmill exercise were studied in nine normal males. Significant changes occurred in all subjects but were unpredictable with regard to magnitude, direction and time of occurrence. The uniformity of the ventilatory response was in sharp contrast to these circulatory variations. Alterations in central blood volume paralleled changes in cardiac output. Physiological mechanisms involved are discussed.

Submitted on August 25, 1960
Extrathoracic airway resistance in man
Authors: Hyatt Robert E. , Wilcox Roger E.
Published: December 2017

Simultaneous extrathoracic and intrathoracic flow resistance was measured in 19 unanesthetized subjects during mouth breathing. Lateral intratracheal pressure was recorded from a needle introduced 2 cm below the larynx. The intratracheal-oral pressure gradient was recorded during various respiratory maneuvers. The pressure drop from esophagus to trachea was also recorded. The extrathoracic pressure-flow relationships were alinear. Large inter- and intrasubject variability in upper airway resistance was encountered. Some factors contributing to this variability were defined. The upper airway accounted for approximately 45% of the total airway resistance in nine normal and 20% in 10 emphysematous human subjects. Upper airway resistance decreased with increasing lung inflation in four normal subjects. The magnitude and potential variability of the upper airway resistance must be considered in evaluating maneuvers designed to alter intrathoracic flow resistance, especially in normal human beings. It appears that during mouth breathing the major component of the upper airway resistance is located in the larynx.

Submitted on September 14, 1960
Pulmonary surface tension and alveolar stability
Authors: Clements John A. , Hustead Robert F. , Johnson Rudolph P. , Gribetz Irwin
Published: December 2017

Human and rat lungs were degassed and filled with air and physiological salt solution for determination of pressure-volume relationships. Extracts were prepared from the specimens and examined for their surface film-forming activity. Both the aeration of the alveolar structure of the lungs at functional residual pressure and the surface activity of the extracts showed wide variation. Numerical ratios were defined to express these two properties quantitatively, and a high degree of correlation was observed between them. The range of correlation was extended by treating the rat lungs with nonionic detergents. These findings support the hypothesis that the stability of the pulmonary alveolar structure is dependent on intrinsic surface-active material and have encouraged further attempts at formulating a theory of alveolar mechanics, taking surface forces into account. The theory is presented, and some of its weaknesses are pointed out.

Submitted on October 21, 1960
Gas exchange after autologous pulmonary embolism in dogs
Authors: Stein Myron , Forkner Claude E. , Robin Eugene D. , Wessler Stanford
Published: December 2017

The ventilatory and arterial blood gas responses to serum-induced thrombi embolized to the pulmonary circulation of the dog have been measured. An increase in rate and minute volume of ventilation independent of the extent of the pulmonary artery obstruction were almost invariably observed. The release of thrombi to the lungs was associated with an arterial-alveolar CO2 tension difference that was dependent on the extent of arterial obstruction. Significant decreases in arterial O2 saturation occurred in animals with massive embolization in the presence of a total minute and alveolar ventilation significantly greater than control values. Failure of arterial O2 concentration to rise to control levels after inhalation of 99.6% O2 indicated that emboli of the dogs' own blood produced a perfusion defect consistent with a right to left shunt.

Submitted on November 21, 1960
Pressure-volume relations of lung and thoracic cage in pulmonary emphysema
Authors: Ting Er Yi , Lyons Harold A.
Published: December 2017

In ten emphysematous and six normal subjects, the pressure-volume curve of the thoracic cage was obtained by arithmetic subtraction, since Pt (total pressure) = Pl (lung pressure) + Pc (thoracic cage pressure). A low compliance of the thoracic cage was found for five emphysematous patients whose total lung capacities (TLC) averaged 93 % of predicted values. In the remaining five patients whose TLC averaged 123% of predicted normal, the compliance values for all the components were nearly normal. In all ten of the patients a normal compliance for lung was found. The respective values of compliance, in liters per centimeter H2O, for the patients with normal TLC were: total respiratory system, 0.039; lung, 0.132; and thoracic cage, 0.056; and for the patients with the larger TLC, were: total respiratory system, 0.075; lung, 0.141; and thoracic cage, 0.154 The major difference was the compliance of the thoracic wall which contributed to the reduction of the compliance of the total respiratory system. The data indicate that some emphysematous patients have a low compliance of the thoracic cage which contributes to the over-all increase in the elastic resistance of the total respiratory system.

Submitted on June 10, 1959
Measurement of cardiac output and "central" blood volume by various systems
Authors: Marshall Robert J. , Allwood Michael J. , Keck Ernst W. O. , Shepherd John T.
Published: December 2017

Dilution curves were obtained by sampling from the aortic root or a carotid artery after injection of indicator dye into the pulmonary artery in five dogs at rest and during exercise. On four occasions a common sampling system was used; curves were recorded simultaneously and in parallel from a cuvette oximeter assembly with a slow dynamic response and from a phototube densitometer with a fast response. In the fifth study, separate slow and fast sampling systems were used interchangeably with the two detecting instruments. Values for cardiac output were similar with the two instruments; maximal divergence for any single observation was 9% from the line of identity. The aortic root is a favorable sampling site for such a comparison, since extrapolation of the dilution curves is usually unnecessary. Under these conditions measurement of cardiac output was not influenced by the dynamic response characteristics of the sampling-detecting-recording system. When mean transit times of the respective curves were corrected for instrumental delay, there was also satisfactory agreement in values for “central” blood volume. However, since the time correction for the densitometer is relatively small, it is the preferable instrument for this measurement.

Submitted on October 24, 1960
Composition and caloric density of weight loss during caloric restriction in cold
Authors: Iampietro P. F. , Goldman R. F. , Mager M. , Bass David E.
Published: December 2017

Two groups of six men each lived for 14 days in a cold chamber at 60 F (15.6 C); activity was sedentary and only athletic shorts were worn. During this period one group, A, was semi-starved (600 kcal/day) and the other, B, was completely starved (0 kcal/day). Changes in body composition were measured and caloric density of weight loss was calculated. Mean weight loss was 5.66 kg for A, and 8.56 kg for B. Composition and caloric density of weight loss was almost identical for both groups. Composition of weight loss with regard to fat, protein and water was 39, 10, and 51% for A; 39, 11, and 49% for B. Caloric density was 3.91 kcal/g for A and 4.06 kcal/g for B.

Submitted on February 20, 1961
Pulmonary hemodynamics during positive-pressure breathing
Authors: Linde Leonard M. , Simmons Daniel H. , Ellman Edward L.
Published: December 2017

The effects of positive-pressure breathing on pulmonary blood flow in the intact anesthetized dog were measured and compared with pulmonary hemodynamics during spontaneous breathing. Using fluoroscopically placed cardiac catheters, pulmonary arterial and venous pressures were measured. Transmural pressures were determined by subtraction of intrapleural pressures, using a differential transducer. Cardiac outputs were determined by the dye-dilution technique, using cardiogreen. Cardiac output fell significantly with positive-pressure breathing, compared with the value during spontaneous respiration. Pulmonary vascular resistance did not differ with the two types of respiration. Although absolute pulmonary arterial and venous pressures rose, as expected, with pressure breathing, their transmural pressures did not change. These studies indicate that there is no primary change in pulmonary hemodynamics with positive-pressure breathing. Decreased cardiac output results from the decreased venous return which is related to the increased intrathoracic pressure during positive-pressure breathing.

Submitted on January 16, 1961
Apparent dye-dilution curves produced by injection of transparent solutions
Authors: Sinclair John D. , Sutterer William F. , Fox Irwin J. , Wood Earl H.
Published: December 2017

In studies on dogs, blood was sampled as for the recording of dye-dilution curves through monochromatic densitometers. Injection of hypertonic media into the superior vena cava caused transient increases in the optical density of blood in the pulmonary and femoral arteries so as to produce apparent “dye” curves. The injection of hypotonic and hemolyzing media produced negative deflections, representing decreases in the optical density of blood, as did brief ventilation with 5% and 50% carbon dioxide in oxygen. Similar changes were demonstrated in vitro. They were compensated for in vivo by the use of a dichromatic densitometer. The changes observed are attributed to altered physical properties of the erythrocytes, which consequently change their light-transmitting and light-reflecting characteristics. Such nonspecific changes in the optical density of blood may constitute an important source of error in monochromatic densitometry done on whole blood.

Submitted on January 11, 1961
Influences of hexamethonium and some dietary factors on human pancreatic and bile secretion
Authors: Hong S. S. , Chin D. S. , Hur K. B.
Published: December 2017

Bile and pancreatic juice were collected from three patients. Each, following sphincterotomy and cholecystectomy, had been subjected to pancreatic and common bile duct intubation. Both milk and 1% dl–methionine by stomach tube increased the volume output of pancreatic juice and bile and also the concentration of amylase, lipase, and cholic acid, respectively. In the case of the pancreas these responses were not seen following hexamethonium but the biliary responses persisted unchanged. A watery decoction of rice increased the volume and enzyme output of the pancreas but did not affect the bile. Bile cholate and volume were increased by 20% glucose solution, water, and beer (5% alcohol). Pancreatic secretion (enzymes and volume) was inhibited by 20% glucose, unchanged by water and stimulated by beer.

Submitted on February 13, 1961
Oxygen in tissues during deep hypothermia
Authors: Byon Y. K. , Adolph E. F.
Published: December 2017

An oxygen electrode and a thermistor were placed in the brain stem, leg muscle, or abdomen of a rat cooled to 17—15 C. When the rat was thereafter kept at 16∘the electrode usually showed a steady current. At 13—11∘ the apparent Po2 of tissue in most instances diminished during 2—3 hr unless artificial breathing was given. Forced breathing of air or oxygen ordinarily raised the Po2; of nitrogen usually, but not always, lowered the Po2. When the apparent Po2 was not thus raised or lowered, the flow of blood to the one tissue being examined, but not necessarily to all tissues, was evidently inadequate. The heart could be stopped reversibly by further cooling to 9—5∘; brain Po2 diminished only gradually at that low temperature. Survival was assured by a Po2 that was high and steady, but often occurred also after a diminishing or zero Po2. In the hypothermic rat, either pulmonary ventilation or systemic blood flow or an unidentified factor could limit the rat's survival.

Submitted on October 26, 1960
Chamber cold acclimatization in man
Authors: Davis Thomas R. A.
Published: December 2017

In March, ten nude subjects were exposed 8 hr daily for 31 days to an air temperature of 11.8 C. In September, another six subjects were similarly acclimatized to an air temperature of 13.5 C. Measurements were made of the responses of shivering, oxygen consumption, rectal temperature, and skin temperature to a standard cold exposure. By the 14th day, shivering in both groups decreased significantly. Heat production remained unchanged in the winter group but decreased in the summer group. Basal metabolism did not change in either group. In both groups, rectal temperatures were maintained at lower values after the exposure period. In the winter group extremity temperatures were unchanged; those in the summer group were lowered by a small amount. The decrease in heat production and mean surface temperature in the summer group is related to the seasonal difference in cold acclimatization. Failure of cold-elevated metabolism to decrease despite a highly significant decrease in shivering indicates the presence of nonshivering thermogenesis in man. It is concluded that man can be artificially cold acclimatized.

Note:

With the Technical Assistance of D. R. Johnston, F. C. Bell, W. Rawlings, and L. Lee

Submitted on May 8, 1961
Surface characteristics of vertebrate lung extracts
Authors: Miller Dean A. , Bondurant Stuart
Published: December 2017

It has been suggested that alveolar stability is due, in part, to the presence of a noncellular alveolar lining which changes surface tension with changing surface area. Extracts of mammalian lungs manifest a decrease in surface tension with decrease in surface area. To compare surface characteristics with respiratory mechanics and anatomy, lung extracts were prepared from amphibians, reptiles, birds, and mammals. Lung extracts from mammalian lungs with true alveolar structure show typical surface tension-surface area characteristics, whereas other vertebrate lung extracts behave similarly to most other biological fluids. An alveolar lining layer with surface behavior similar to mammalian lung extracts would be expected to contribute to alveolar stability.

Submitted on June 28, 1961
Disappearance of plasma radioactivity after injection of H3- or I131-labeled arginine vasopressin
Authors: Silver Lawrence , Schwartz Irving L. , Fong Conrad T. O. , Debons Albert F. , Dahl Lewis K.
Published: December 2017

Tritiated and iodinated arginine vasopressin (AVP) were administered intravenously to human beings and to dogs. The level of plasma radioactivity was measured with time and showed a single exponential function in all cases, except with I113 vasopressin in human beings, where two exponential components were evident. In the dog, the half-time for the disappearance of radioactivity from plasma ranged from 3.5 to 7 min after administration of I113 AVP and from 4 to 5 min after H3 AVP. In similar experiments in man, I113 AVP gave a fast component with a half-time ranging from 0.3 to 2 min and a slow component with a half-time ranging from 1.6 to 6.5 min, whereas H3 AVP gave a single component with a half-time ranging from 2.3 to 5.5 min. The similarity in the disappearance curve of antidiuretic activity and the disappearance curve of radioactivity suggests that the latter reflects the rate of degradation of the biologically active hormone. Therefore, these labeled hormones appear to be useful tools for evaluation of vasopressin turnover in physiological and clinical conditions alleged to be associated with increased levels of circulating antidiuretic hormone or with abnormal rates of vasopressin production, release, or inactivation.

Submitted on March 9, 1961
An electronic stimulator for biological experiments
Authors: Kersey J. W. , Quigley J. P.
Published: December 2017

Page 1143: J. W. Kersey and J. P. Quigley, “An electronic stimulator for biological experiments.” The following footnote should be added at the end of the article: To eliminate stimulus artifacts, one signal magnet terminal should be connected to the stimulator chassis and the chassis should be connected to an earth-ground.
Importance of diffusion and chemical reaction rates in O2 uptake in the lung
Authors: Staub N. C. , Bishop J. M. , Forster R. E.
Published: December 2017

The Bohr integration procedure for the approximate solution of the blood O2 tension along the pulmonary capillary from known values of alveolar, mixed venous, and end capillary O2 tensions and the O2 hemoglobin dissociation curve assumes, among other things, that the dissolved O2 in the blood is always in equilibrium with the hemoglobin, in other words that the exchange of O2 between the red cells and the plasma is instantaneous. Previous work (J. Appl. Physiol. 16: 511, 1961) has shown that, on the contrary, the experimentally measured rates of O2 uptake of the red cells are slow enough to limit the uptake of this gas in the alveolar capillaries. Therefore we have developed a method analogous to the Bohr integration for obtaining an approximate solution for the O2 tension of the plasma and of the red cells along the pulmonary capillary where Dl is a function of O2Hb saturation. Examples are given for a normal individual and an individual with severe anemia both breathing air and 14% O2.

Submitted on July 18, 1961
Influence of pressure suit inflation on pulmonary diffusing capacity in man
Authors: Ross Joseph C. , Ley Glen D. , Coburn Ronald F. , Eller J. L. , Forster Robert E.
Published: December 2017

Previous investigations of the effect of inflation of a pressure suit on pulmonary diffusing capacity (DL) have been reported from our two laboratories, one (Indianapolis) finding an increase and the other (Philadelphia) finding no change. The present investigation was carried out in Philadelphia, using some of the same subjects and pressure suits in order to reconcile the contradictory results. The earlier contradictory results were confirmed. The pressure suit used in the investigations at Philadelphia ( suit P)covered the entire body below the nipples, whereas the suit used in the investigations at Indianapolis( suit I) extended cephalad only as far as the costal margin. When suit P was inflated in the present study, DL again did not increase significantly in two subjects. However, when the upper part of the suit was folded down so that the thoracic cage was not covered, inflation of the suit did produce a significant increase in DL. Inflation of suit P when it covered the chest made it difficult for a subject not to perform a Valsalva maneuver during breath holding and caused more decrease in alveolar volume (Va) than when it was inflated in the folded-down position. In two subjects studied, we found no difference in air trapping with inflation of suit P in the two positions. The discrepancy between the results of the two earlier studies appears to have resulted from the different construction of the two pressure suits used. We conclude that pressure suit inflation in man will produce an increase in DL, presumably by means of pulmonary congestion.

Submitted on September 22, 1961
A principle for counting tissue structures on random sections
Authors: Weibel Ewald R. , Gomez Domingo M.
Published: December 2017

A new principle is derived from mathematical considerations which will allow the calculation of the number of bodies contained in the unit volume by counting the number of transections on the unit area of a random section. The simple equation involves two coefficients related to the volumetric density of the bodies in the volume, and to their configuration. Means for the accurate determination of these coefficients are given. The verification of this principle in model experiments showed a high degree of reliability of the method with average errors of estimate of 2–4%. The method has been applied to the counting of alveoli in five normal human lungs, which were found to number an average of 300 million, with a striking constancy from lung to lung.

Submitted on May 31, 1961
Compensatory nystagmus conditioned during adaptation to living in a rotating room
Authors: Guedry Fred E. , Graybiel Ashton
Published: December 2017

Seven men were rotated at 5.4 revs/min in a room for 64 hr. Controlled tests before and during this interval demonstrated that disorientation and nystagmus attributable to Coriolis acceleration effects diminished markedly. A compensatory nystagmus, induced by head or whole-body movements, was recorded more than 1 hr after the rotation had ceased. Factors of possible significance in conditioning the compensatory nystagmus are: 1) otolith and proprioceptor sensory influx prior to and during discordant canal input: 2) a consistent sensory influx for each stimulus-producing movement: 3) intention in stimulus-producing movements: 4) visual inhibition. Contributions of compensatory and arousal factors to vestibular suppression are considered in relation to practical problems of transfer of habituation from one acceleration environment to another.

Submitted on December 1, 1961
Effect of oxytocin on myoepithelium of the breast
Authors: Wiederman Joseph , Stone Martin L.
Published: December 2017

A laboratory study was made of the response of the myoepithelium of the postpartum human breast to synthetic oxytocin, comparing the effects of intranasal and intravenous administration. A clinical study was also undertaken to assess the effects of intranasal oxytocin on breast engorgement. Intramammary pressure was obtained directly through a polyethylene catheter placed in the mammary duct and connected to a pressure transducer and Poly-Viso recorder. A myoepithelial response was elicited by a threshold dose of 2 mU of oxytocin intravenously. Intranasal spray produced responses similar in amplitude to intravenous doses when applied in amounts 200 times the intravenous dose. The response pattern of intranasal spray was that of a series of contractions, whereas intravenous doses produced single contractions. The lag time from administration to response was 100 sec with intranasal oxytocin vs. 20 sec with intravenous doses. Clinically, a twice-a-day application of intranasal spray oxytocin appeared to accelerate the normal physiologic process of involution in nonnursing mothers.

Submitted on November 22, 1961
Radiant temperature of the zenith at altitude
Authors: Hammel H. T. , Hardy J. D.
Published: December 2017

Using a thermistor radiometer, measurements have been made of the radiant temperature of the zenith sky from ground level to 40,000 ft. The lowest temperatures measured were near -135 C, with an air temperature near -50 C at 36,000 ft. There was a high variability in sky temperature at altitude not observed at ground level. Although the low sky temperature as compared with air temperature points to the large thermal load imposed by radiant heat loss on man exposed to a high-altitude thermal environment, computation indicates this would amount to only about 77 Kcal/m2/hr for the completely clothed pilot.

Submitted on October 26, 1961
Diffusing capacity and blood flow in different regions of the lung
Authors: Spicer W. S. , Johnson R. L. , Forster R. E.
Published: December 2017

We have measured the disappearance of CO and, in most instances, acetylene relative to helium from early and late portions of the expired alveolar gas after 1.5–20 sec of breath holding at rest in four normal subjects and seven patients with obstructive emphysema and three with sarcoidosis. In all individuals, except one patient with emphysema, graphs of the logarithm of the relative expired alveolar CO concentrations in early and late expired samples against time of breath holding were parallel, but those for the late expired samples lay below these for the early expired samples. The equality of the slopes of the two curves indicated that net diffusing capacity/alveolar volume for those regions of the lungs contributing to the two samples is similar even in severe obstructive disease. The displacement of the disappearance curves can be explained by errors in estimation of the time the gas spends in the alveoli and by an increased rate of CO disappearance caused by reduced alveolar volume during expiration.

Submitted on December 18, 1961
Respiratory dynamic resistance
Authors: Long Ernest Croft , Hull Wayland Elroy , Gebel Emile Louis
Published: December 2017

Sinusoidal forcing at frequencies up to 17 cycles/sec was applied to the anesthetized, apneic dog by a body respirator. Forcing pressure and volume displacement were displayed in quadrature on an oscilloscope and planimetric integration of these loops indicated an increase in energy dissipated by total respiratory resistance per liter of air displaced, due to turbulence and changing airway geometry, with increasing frequency. Nonlinear resistance was calculated and the differential coefficient, dP/dV (dynamic resistance), was determined at 10° intervals throughout the respiratory cycle, at each of three frequencies in four dogs. Total respiratory resistance is a “nonohmic” dependent variable and changes progressively throughout the cycle.

Submitted on October 20, 1961
Mechanism of bronchoconstriction during inhalation of dust
Authors: Widdicombe John G. , Kent Donald C. , Nadel Jay A.
Published: December 2017

Inhalation of fine charcoal dust decreased airway conductance (increased resistance) in man. Subcutaneous injection of atropine blocked this effect. In paralyzed and artificially ventilated cats, inhalation of dust increased total pulmonary airflow resistance. This was prevented by blocking conduction in the cervical vagosympathetic nerves. Inhalation of dust stimulated activity in single afferent nerve fibers arising in the trachea and also increased activity in efferent parasympathetic nerve fibers going to the lungs. These results establish the reflex nature of bronchoconstriction during inhalation of dust and show its dependence on the cervical vagosympathetic nerves.

Submitted on February 1, 1962
Additive effects of acetazolamide and fat emulsion on alveolar-arterial Pco2 difference
Authors: Cain Stephen M.
Published: December 2017

Alveolar and arterial gas tensions were measured in anesthetized dogs during a control period, after intravenous injections of a carbonic anhydrase inhibitor, and after rapid intravenous infusion of fat emulsion. These were carried out in sequence. The alveolar-arterial (A-a) Pco2 difference increased from about 6 mm Hg during the control to 26 mm Hg after carbonic anhydrase inhibition. A further increase took place after fat emulsion when the A-a Pco2 difference averaged 35 mm Hg. There was no increase in the A-a Po2 difference between carbonic anhydrase inhibition and fat emulsion. The additive increase in the A-a Pco2 difference strongly suggested that fat emulsion did not further interfere with the interconversion of CO2 and bicarbonate.

Submitted on February 8, 1962
Effects of chest compression on reflex ventilatory drive and pulmonary function
Authors: McIlroy Malcolm B. , Butler John , Finley Theodore N.
Published: December 2017

External compression of the chest sufficient to reduce the lung volume (FRC) by 1 liter in eight normal subjects interfered with the mechanical function of the lungs. We have confirmed the findings of Caro et al. ( J. Clin. Invest. 39: 573, 1960), who showed a decrease in lung compliance and an increase in respiratory rate. Neither returned to normal when the compressing force was removed, and it was not until the subject took a deep breath that the lungs returned to their control state. We also found a reduction in anatomical dead space and alveolar hyperventilation. Arterial blood gas tensions showed evidence of complex ventilation-perfusion abnormalities, which could not be explained by any single factor. We think the hyperventilation associated with chest compression is reflex in origin and related to a decrease in lung volume rather than to any change in transpulmonary pressure.

Submitted on January 4, 1962
Effects of chronic acceleration on induced nystagmus in the fowl
Authors: Winget Charles M. , Smith Arthur H. , Kelly C. F.
Published: December 2017

Domestic fowl exposed to chronic acceleration (prolonged centrifugation) do not appear to “habituate” to repeated rotatory stimulation, as do similarly treated birds maintained at normal gravity. Chronically accelerated birds frequently exhibit postural or locomotor abnormalities, and such individuals lack a nystagmic response to rotatory stimulation.

Submitted on August 21, 1961
DlCO measurements with gas chromatography
Authors: Smith Josef R. , Hamilton Lyle H.
Published: December 2017

A gas chromatograph has been used to analyze gases for the measurement of pulmonary diffusing capacity using the breath-holding technique. The gas mixture used for the measurement consisted of carbon monoxide in air with neon as the insoluble inert gas. The calculated DlCO was unaffected when sulphur hexafloride (SF6) or He was substituted for Ne in the mixture, but since CO and Ne could be most simply and rapidly analyzed, this combination was preferred for the gas mixture used to measure DlCO. The mean DlCO for ten normal subjects was 25.8 ± 4.2 ml/min mm Hg. These results were comparable to values reported in the literature when established methods of analysis were used. An excellent correlation was found between calculated DlCO and the clinical condition of patients with impaired pulmonary diffusing capacity.

Submitted on February 14, 1962
Effect of whole-body vertical vibration on respiration in human subjects
Authors: Duffner Lee R. , Hamilton Lyle H. , Schmitz Melvin A.
Published: December 2017

The respiration of ten healthy male subjects was studied during 4-min exposures to vertical whole-body vibration of 0.15 and 0.35 g peak acceleration intensities of frequencies of 2 through 7 cycle/sec. Initial hyperventilation, with a subsequent return toward normal levels, occurred during the period of vibration. The breathing frequency decreased and the end-expiratory position dropped, but the vital capacity was not changed. Vibration-induced hyperventilation was most pronounced at 4–5 cycle/sec. Oxygen consumption was increased during vibration, with a maximum increase observed at the lowest frequencies. All changes were greater at 0.35 g than at 0.15 g acceleration. Except for a decreased alveolar CO2 concentration, respiration during the 4-min recovery period did not significantly differ from the previbration levels.

Submitted on May 14, 1962
Quantitation of effects on mitochondrial swelling: some effects of ATP and aging
Authors: McGaughey Charles
Published: December 2017

A method has been devised for the quantitative measurement of relative effects of substances or conditions on rate of change of mitochondrial volume. It can be used to study the effects progressively as the mitochondria swell. By this means, the effects of adenosine triphosphate (ATP) and aging on mitochondrial swelling were investigated. It was found that at constant mitochondrial volume, the rate of change of volume is a logarithmic function of aging time. The swelling of fresh mitochondria was mildly inhibited by ATP at very low volumes. Aging of rat liver mitochondria caused this inhibitory effect to be replaced by enhancement of swelling, which became greater in magnitude and was retained through larger volumes as aging time increased. The swelling enhancement was followed by inhibition, the magnitude of which increased with further swelling. The inhibitory effect of ATP on swelling of mouse liver mitochondria underwent a sudden marked increase at a particular mitochondrial volume independent of aging time and time of ATP exposure. At lower volumes the effect of ATP increased with aging time and swelling rate, whereas at larger volumes this relation ceased to be apparent. The possible significance of these results is discussed.

Submitted on January 22, 1962
Thermodilution studies of ventricular volume changes due to isoproterenol and bleeding
Authors: Bristow J. David , Ferguson Richard E. , Mintz Fredric , Rapaport Elliot
Published: December 2017

The effects of intravenous isoproterenol on left ventricular stroke and on end-systolic and end-diastolic volumes were studied in anesthetized dogs before and after bleeding. Volumes were measured by a thermodilution technique. In this indicator-dilution method a small amount of cooled blood is rapidly injected into the ventricle, and the washout of cold from the ventricle is sensed by a thermistor catheter at the root of the aorta. Control values showed that approximately two-thirds of the end-diastolic volume remained in the ventricle at the end of systole. Bleeding decreased all three volumes. Isoproterenol consistently increased ventricular emptying, as shown by the fall in the proportion of the end-diastolic volume which remained at end systole. This effect did not depend on an increase or decrease in the end-diastolic volume itself. End-systolic force-circumference relationships were derived from a consideration of idealized ventricular dimensions. A linear relationship between these calculated values was not altered by isoproterenol.

Submitted on July 5, 1962
Influence of metabolism on uptake of CO and O2 by hemoglobin in erythrocytes
Authors: Sirs John A.
Published: December 2017

The initial rate of oxygen uptake by hemoglobin in sheep erythrocytes, measured within 3 hr of blood collection, was found to be considerably higher than values previously observed. No similar effect was observed with carbon monoxide unless oxygen was also present. A decay curve of the initial rate with time, obtained on human erythrocytes, indicates that the cells reach a passive level within 2 hr in the absence of oxygen. The process is inhibited by NaF and no advantage was obtained on suspending the cells in their own plasma, rather than Ringer-Locke solution. An analysis of the results suggests that the membrane is increased by cell metabolism.

Submitted on September 21, 1961
Diaphragm activity during breath holding: factors related to its onset
Authors: Agostoni Emilio
Published: December 2017

The electrical activity of the diaphragm during breath holding has been studied. After a period of no or slight tonic activity a marked discharge is recorded, this is followed by others at a progressively higher rate up to the breaking point. The action of the diaphragm, not balanced by antagonist muscles, causes a fall of the intrathoracic pressure. The period of breath holding, in most subjects, may be divided into two parts: the first, characterized by voluntary inhibition of respiratory muscles activity; the second, by involuntary respiratory efforts. The standard error (se) of alveolar Pco2 values determined at the onset of diaphragm activity in groups of three similar tests is <0.5 mm Hg. Arterial Pco2 in the brain stem at the onset of diaphragm activity has been estimated: breathing O2 the mean values ±se in three subjects were, respectively, 46.2 ± 0.3, 46.4 ± 0.2, and 50.2 ± 0.2. The onset of diaphragm activity seems not affected by neurogenic factors related to lung volume or respiratory movements. An alveolar Pco2 – Po2 curve at the onset of diaphragm activity has been determined.
Physiological effects of continuous or intermittent work in the heat
Authors: Lind A. R.
Published: December 2017

To define thermal limits for everyday work, a possible criterion which has been put forward described the climates (“prescriptive” climates) in which the level of bodily thermoregulation remained steady for a given rate of work. The present experiments were intended to determine the effect on results, obtained from brief exposures involving continuous work, of extending the exposure to a period of 8 hr and of presenting a given total energy expenditure (2,100 kcal) in different patterns of work and rest. During 8-hr exposures to three climates with dry and wet bulb temperatures of 29.4 and 23.9, 36.7 and 25.6, and 41.1 and 28.3 C, respectively, two subjects expended approximately 2,100 kcal in both 1) a nearly continuous level of activity and 2) intermittent bouts of much harder work interspaced by longer periods of rest. Evaluation and comparison of the results show that extension of exposures to periods of up to 8 hr per se did not demonstrably change the levels of rectal temperature, pulse rate, or weight loss found by the 2nd hr of exposure in the climates examined. Further, in prescriptive climates (in which the level of thermoregulation depends on the rate of work rather than on the environment), when the energy expenditure was 2,100 kcal in 8 hr, either continuously at a moderate rate, or intermittently at a high rate with compensatory rest pauses, the physiological cost was similar, as judged by rectal temperature, pulse rate, and weight loss.

Submitted on June 15, 1962