bluuebunny/crossref_metadata_2025 huggingface dataset:
Influences of exercise and O2 on breath holding
Authors: Craig Albert B. , Halstead Lauro S. , Schmidt Gerhard H. , Schnier Brian R.
Published: December 2017

The PaCOCO2 at the breaking point was found to be higher during exercise than during rest in four subjects. The breaking-point curve during exercise was elevated over the entire range of various oxygen concentrations studied, indicating that whatever the changes produced they are related to the contribution of CO2 to the urge to breathe and are independent of O2. At least part of the elevated PaCOCO2 may be accounted for by an overshoot of PaCOCO2 related to the rate of rise of Pco2. This was shown by increasing the rate of accumulation of CO2 by inhaling different O2-CO2 gas mixtures to simulate the increased CO2 production during exercise. However, certain calculations indicate that this is not the only difference between voluntary apnea during exercise as compared with that during rest.

Submitted on June 30, 1961
Adrenal cortical response to chronic hypoxia
Authors: Hornbein Thomas F.
Published: December 2017

Although acute oxygen lack causes increased adrenal cortical activity, there is evidence that continued exposure to hypoxia is accompanied by a return of adrenal cortical function to its sea level status. To evaluate the adrenal cortical response in men living for 14-21 days above 21,000 ft, urinary output of 17-hydroxycorticoids was measured in ten members of a Himalayan mountaineering expedition and compared to values obtained subsequently at sea level. No significant difference in 17-hydroxycorticoid output was observed between the two altitudes. The response of four subjects to the administration of Su-4885 (Methopyrapone) showed that the pituitary-adrenal cortical system was still capable of response to additional stimulation.

Submitted on July 31, 1961
Respiratory response to forward acceleration compared with chest compression in dogs
Authors: Zechman Fred W. , Taylor Justin
Published: December 2017

Six mongrel dogs were studied to determine if the increases in frequency of breathing characteristic of both chest compression and forward acceleration are initiated by the same vagal reflex. Since vagal section only abolished the response to chest compression, it is assumed that some other mechanism is primarily responsible for the rate increase characteristic of forward acceleration. Experiments are also described which suggest that the increased respiratory frequency may be attributed to a hypoxic drive.

Note:

(With the Technical Assistance of N. P. Clark)

Submitted on December 7, 1961
Effect of reserpine on cardiovascular response to smoking
Authors: Westfall Thomas C. , Watts Daniel T.
Published: December 2017

It has been shown that blood pressure and pulse rate are increased and skin temperature of the extremities is decreased when normal subjects smoke two-thirds of two cigarettes during a period of about 15 min. This standard smoking test has been performed on university students before and after treatment with reserpine (0.25 mg daily) to determine the effect of reserpine on cardiovascular responses to smoking. Blood pressure, pulse rate, finger and toe temperature changes were recorded before and during the smoking test in untreated students and after administration of reserpine for 14 days. The maximum change from control values in ten untreated students and after 14 days of reserpine, respectively, along with P values for differences were as follows: systolic blood pressure (mm Hg) +17, +8, P < .001; diastolic blood pressure (mm Hg) +14, +7, P < .001; pulse rate (beats/ min) +27, +13, P < .001; finger temperature (F) -6.4, -4.0, P < .1; toe temperature (F) -2.7, -4.2. Results show that the characteristic increase in blood pressure and pulse rate and, to a lesser extent, the decrease in finger temperature due to smoking are reduced by pretreatment with reserpine.

Submitted on July 10, 1961
Local circulation in heart muscle studied with Na24 clearance method
Authors: Salisbury Peter F. , Cross Cecil E. , Oblath Robert W. , Rieben P. Andre
Published: December 2017

Neutral, isotonic Na24Cl solution was injected into the left ventricular wall of open-chest dogs. The disappearance of local radioactivity was recorded. Individual injections that exceeded 5 mm3 retarded Na clearance. The rate of Na clearance from individual deposits did not measure coronary flow in absolute terms; however, when one hemodynamic parameter was suddenly changed 50–200 sec after the injection of a radioactive deposit, the changed Na clearance slope reflected directional variations of coronary flow. In ischemic regions of self-perfused hearts, elevation of aortic pressure that was paralleled by increased left ventricular and central coronary pressures did not always result in more rapid Na clearance.

Submitted on November 24, 1961
Comparison of computed aortic blood velocity with that of electromagnetic flowmeter
Authors: Jones W. B. , Griffin J. B.
Published: December 2017

The probe of an electromagnetic flowmeter was placed on the ascending aorta of five dogs. Aortic blood pressure was obtained from the same area. This pressure signal was fed into a simple computer circuit designed to solve a modification of the Navier-Stokes equation. The output of this circuit was assumed to be proportional to blood velocity and was compared directly with the velocity obtained with the electromagnetic flowmeter. The peak amplitudes and the stroke volumes (represented by the area under the velocity tracings), obtained simultaneously by the two different methods, were compared. Each dog was bled, transfused, and given methoxamine and nitroglycerin to produce a wide variation in stroke volume and blood pressure. A correlation coefficient of .93 was obtained from 350 paired stroke-volume values. Thus, it appears that in a wide variety of conditions, stroke volume may be derived from the aortic pressure pulse by the computer technique.

Submitted on October 27, 1961
Influence of voluntary hyperventilation on cardiac output
Authors: Donevan R. E. , Anderson N. M. , Sekelj P. , Papp O. , McGregor M.
Published: December 2017

The influence of voluntary hyperventilation on cardiac output was studied in six sitting and four supine subjects by the dye dilution method, using an ear oximeter. All studies were made during the performance of a steady work load of 150 kg-m/min. on a bicycle. There was a positive correlation between increase in ventilation and increase in cardiac output, the average ratio being 41 ml blood/liter ventilation increase. This was not affected by the duration of hyperventilation for periods up to 75 sec and was of the same order in the supine or sitting position. When the thoracic pressure changes of hyperventilation were simulated by raising airway resistance without increase in ventilation there was no correlation between changes in pressure and cardiac output. Thus, it could not be shown that the influence of hyperventilation on circulation was due to the mechanical effect of intrathoracic pressure on venous return, though the increased work of breathing may have been partly responsible for the change in cardiac output observed.

Submitted on August 21, 1961
Elastic properties of single elastic fibers
Authors: Carton Robert W. , Dainauskas John , Clark John W.
Published: December 2017

The elastic properties of elastic tissue were studied in a situation which minimized the effects of extraneous connective tissue and of the position of fibers in the elastic network. Single elastic fibers were dissected free from the ligamentum nuchae of the ox and were stretched under conditions of constant temperature and salinity. The strain was an exponential function of the applied tension. Single fibers were found somewhat less stretchable than the ligaments from which they were taken. The data given can be used to calculate the contribution of such elastic fibers to the behavior of an elastic system in which they are incorporated.

Submitted on August 7, 1961
Effect of exercise, body and lung size on CO diffusion in athletes and nonathletes
Authors: Newman Faith , Smalley B. F. , Thomson M. L.
Published: December 2017

A comparison of pulmonary alveolar-capillary diffusion was made on groups of 11 athletes and 9 nonathletes closely matched in body size and age. The modified Krogh breath-holding technique was employed both at rest and during exercise on a bicycle ergometer. Mean maximal values of Dco, kco, and Vo2 were significantly higher in athletes than in nonathletes ( P < 0.01). Pulmonary permeability (kco) rose rectilinearly with Vo2. The mean graph for athletes was parallel to but higher than that for nonathletes. The equality in slopes was attributed to the matching of the two groups in body size. Evidence that the higher level in athletes was due to their higher degree of training was provided by one nonathletic subject whose permeability rose during training to the mean athletic level. The relation between permeability, body and lung size, and Vo2 is discussed.

Submitted on December 26, 1961
Effects of adrenaline and noradrenaline on ear vessels in cold- and warm-adapted rabbits
Authors: Honda Nishio , Judy William V. , Carlson Loren D.
Published: December 2017

Cold exposure increases the secretion of catecholamines and enhances the effect of these hormones on metabolism. Whether the sensitivity of peripheral vessels to adrenaline and noradrenaline is altered by cold exposure has not been reported. Warm-adapted (27 ± 1 C) and cold-adapted (5 ± 1 C) rabbits were studied under chloralose or urethan anesthesia. Adrenline and noradrenaline were infused (3 μg/kg/min) through an car vein. Colonic plus car temperature, ECG, blood flow, and venous pressure in the ear were measured. Compliance of ear veins was calculated from the ΔV/ΔaP at pressures of 20 and 30 mm Hg. After prolonged cold exposure rabbits responded to catecholamine infusion (adrenaline and noradrenaline) with less change in heart rate during infusion and a more rapid return to control levels following infusion; with less decrease in ear temperature during infusion and a more rapid return to control levels following infusion, less increase in peripheral resistance, and less effect on compliance of the capacitance vessels (veins). The infusion caused a slight rise in colonic temperature in both groups.

Submitted on March 19, 1962
Mechanical efficiency of rhythmic and paced work of lifting
Authors: Rönnholm Nils , Karvonen Martti J. , Lapinleimu Veikko O.
Published: December 2017

Weights of from 2 to 10 kg were lifted to levels 5–44 cm higher and back again at the rate of 10–40 cycles/min. The optimum rate in terms of energetic efficiency was 20–30 lifts/min. With this rate, a load of 5 kg, and a lift of 12 cm, about half as much energy was expended when the subjects were permitted rapid, rhythmic completion of lifting and a compensatory pause during each frac12 min of scheduled work as when the same amount of work was performed at equal intervals throughout. The difference between rhythmic and paced work diminished to zero as the number of lifts was increased to 40/min. At loads of 2 and 10 kg and also over the distance of 5 and 44 cm, paced and rhythmic work required equal energy expenditure. The heart rate was also slower in rhythmic than in paced work. The difference was largest (16/min) when lifting 5 kg over 12 cm at the rate of 30 lifts/min. The introduction of an element of rhythm (and compensatory pause) thus resulted in a marked saving of physiological effort under strictly defined conditions.

Submitted on November 13, 1961
Pulmonary diffusion in the dog lung
Authors: Niden Albert H. , Mittman Charles , Burrows Benjamin
Published: December 2017

Methods have been presented for assessing pulmonary diffusion by the “equilibration technique” in the experimental intact dog and perfused lung while controlling ventilation with a whole body respirator. No significant change in diffusion of carbon monoxide was noted between open and closed chest anesthetized animals, with duration of anesthesia in the intact dog, or with duration of perfusion of the isolated dog's lung. There was no demonstrable difference in diffusion when arterialized blood was used as the perfusate in place of mixed venous blood in the lung perfusions suggesting that within the range studied the Po2, Pco2, and pH of pulmonary artery blood does not directly affect the diffusion of carbon monoxide. Retrograde perfusions of dogs' lungs did not significantly alter diffusion, suggesting that pulmonary venous resistance was not significantly lower than pulmonary arterial resistance in the perfused dog lung at the flows and pressures studied. The equilibration technique for measuring pulmonary diffusion and assessing the uniformity of diffusion was well suited to the study of pulmonary diffusing characteristics in the experimental animal.

Submitted on January 8, 1962
Energy intake and expenditure of medical college women
Authors: Banerjee Sachchidananda , Mahindra Santosh Kumari
Published: December 2017

Energy intake and output were determined in 11 women students of a medical college by analyzing the daily food consumed for protein, fat, and carbohydrate, recording the time spent in different activities, and analyzing the expired air during each activity. The period covered was 1 week. The average daily intake per student was 1,406 kcal and expenditure was 1,410 kcal. The average daily intake of protein, fat, and carbohydrate per girl was, respectively, 44.7 g, 43 g, and 210 g, which furnished 13, 27, and 60% of the total energy, respectively. Of the total energy 64% was expended in sleep, study, and rest, though these activities took 75% of the time. Ascending and descending stairs entailed more energy than cycling. Household work performed in a sitting position required more energy than standing activities (dancing, running, etc.). Energy intake and output just balanced, and the weight of the girls did not change during 1 week of the study.

Submitted on March 13, 1962
Elevation of plasma antithrombin in the aging arteriosclerotic subject
Authors: Pilgeram L. O. , Schram A. C. , Loegering D. A.
Published: December 2017

Plasma samples from aging human subjects who had recovered from the trauma of a myocardial infarct and who were not on anticoagulant therapy were assayed for antithrombin activity. Antithrombin was assayed by methods which measure the ability of plasma to destroy an excess of thrombin, human or bovine in origin. Residual thrombin was quantitated either by clotting time or by hydrolysis of TAME ( p-toluene sulfonyl-l-arginine methyl ester-HCl). All methods showed unequivocally that plasma antithrombin increases up to 33% ( P < 0.002) in subjects who have fully recovered from a thrombotic episode.

Submitted on October 19, 1962
Nature of "imperfect" elasticity of articular cartilage
Authors: Elmore Stanley M. , Sokoloff Leon , Norris George , Carmeci Peter
Published: December 2017

A low friction apparatus for measuring the compression of articular cartilage during static loading and subsequent recovery under conditions of immersion is described. The instrument system employed a specially designed balance lever and sensing transducer that recorded load and displacements as a function of time. Unlike the findings of past experiments conducted in air, measurements made in Hanks' balanced salt solution disclosed restitution of the compressed cartilage, following removal of loads up to 82.5 gm/mm2, to its original thickness. The measurements were affected by the tonicity of the immersion medium. The so-called imperfect elasticity of articular cartilage previously reported in the literature thus is an artifact.

Submitted on August 7, 1962
Relation between pressure and diameter in main pulmonary artery of man
Authors: Greenfield Joseph C. , Griggs Douglas M.
Published: December 2017

The pressure-diameter relationship in the main pulmonary artery of man was estimated in 11 patients undergoing open-heart surgery. The diameter was measured with a recording caliper sutured to the vessel wall. The lateral intravascular pressure was measured with a 20-gauge needle connected directly to a Statham P23Db strain gauge. In the eight patients with normal pulmonary artery pressure the results indicate: 1) the shapes of the pressure and diameter curves are similar; 2) the mean value for the ratio of change in radius to change in pressure (ΔR/ΔP) x 103 was 8.77 cm/cm H2O (±sd 2.10); 3) the mean value for the pressure-strain elastic modulus (Ep) was 159.0 g/cm2 (±sd 26.0); and 4) the mean change in cross-sectional area during an average cardiac cycle was 22.9% of the diastolic value. In three patients with pulmonary hypertension the value of both ΔR/ΔP and the pressure-strain elastic modulus was lower.

Submitted on April 27, 1962
A veni-venomotor response to local congestion
Authors: Wallis William , Brenman Robert , Honig Carl R.
Published: December 2017

Using the occluded venous segment technique a venoconstrictor response to local congestion was demonstrated in human limbs. Though the response appears to be dependent upon nerves, it may or may not involve the central nervous system. Results are discussed in terms of the mechanism and functional significance of the local vascular ℌreflex.ℍ

Submitted on December 6, 1962
Respiratory control in uremic acidosis
Authors: Pauli H. G. , Reubi F.
Published: December 2017

Lambertsen and co-workers were able to correlate increments in ventilation produced by a number of acute experimental acid-base derangements in man with combined shifts in H ion concentration in blood and cerebrospinal fluid. Comparing hyperventilation in a group of uremic acidotic patients with ventilation levels of a control group by the same criteria shows that the measured values in uremic subjects are lower than those predicted. The tentative conclusion may be drawn that in chronic renal failure the respiratory center is adapted to blood acidosis by an elevation of its threshold level for the H ion stimulus.

Submitted on August 2, 1962
Effect of vascular pressure and blood flow on CO diffusion in the perfused dog lung
Authors: Burrows Benjamin , Niden Albert H.
Published: December 2017

The effects of blood flow and vascular pressure on the pulmonary diffusing capacity for carbon monoxide have been studied independently in 18 isolated perfused dog lungs, using the “equilibration technique” for Dl determination. The Dl is a function of mean vascular pressure over a wide range of vascular tensions, suggesting that there are some lung capillaries with high closing pressures or that patent pulmonary capillaries are capable of dilating in response to an increase in their transmural pressure. A maximum Dl could not be obtained. Measured Dl is reduced with low rates of pulmonary blood flow, but its dependence on perfusion rate becomes slight as physiologic flow rates are approached. Nonuniform diffusing capacity: lung volume ratios throughout the lung are noted at both low intravascular pressure and low blood flow, indicating nonuniformity of capillary filling and/or nonuniformity of capillary erythrocyte transit times. Under the conditions of these experiments, Dl appears to be dependent on blood flow per se as well as related to changes in pulmonary vascular resistance.

Submitted on November 14, 1962
Exercise blood flow changes in the human forearm during physical training
Authors: Rohter Frank D. , Rochelle Rene H. , Hyman Chester
Published: December 2017

Forearm blood flow measurements were made with a venous occlusion plethysmograph on six competitive swimmers and six control subjects at rest and during a prescribed rhythmic exercise throughout a 13-week training and detraining program. The swimmers‗ mean exercise forearm blood flow increased progressively during the training program, reaching a maximum at the peak of training toward the end of the 5th week, after which it decreased to near posttraining levels during the period of detraining. The increase in the swimmer's exercise flow between the 1st week of training (4.02 ± 0.59 ml/100 ml min) and the 5th week of training (6.40 ± 0.56 ml/100 ml min) was statistically significant; their decrease in mean exercise blood flow during the 3rd week of detraining (4.70 ± 0.24 ml/100 ml min) was also statistically significant. There was no significant change in the swimmers' resting blood flow; nor were there significant changes in either the exercise or the resting blood flows of the control group. The technique for measuring blood flow in the forearm during rhythmic exercise is explained.

Submitted on December 11, 1962
A simplified method for obtaining cerebrospinal fluid pressure measurements in the dog
Authors: Verdura Javier , White Robert J. , Kretchmer Henry
Published: December 2017

A simplified method for recording the cerebrospinal fluid pressure in the dog is presented. It consists of introducing the polyethylene tube of a Rochester needle into the sub-arachnoid space at the level of the ventral atlanto-occipital joint. The advantages of this technique are: the dura mater is punctured under direct vision; a completely sealed fluid system results which permits direct inspection for cerebrospinal fluid leakage; and the animal may be placed in any anatomical position during the continuous monitoring of cerebrospinal fluid pressure. This method of measuring the cerebrospinal fluid pressure has been utilized in 30 canine experiments and has proven equally effective in recording cerebrospinal fluid pressures in monkeys.

Submitted on December 21, 1962
Experimental ocular pathology related to corneal transmittance and infrared psychophysics
Authors: Dawson William W.
Published: December 2017

The corneas of 26 cats were irradiated by a 3,250 K source at dose rates of 7.04 gcal/sec cm2. The incidence of cataract, corneal leukoma, and other anomalies was related to total dose levels which ranged from 25–400 gcal/cm2. Generation of lenticular opacities and associated long latent periods was related to current theory, corneal transmission, and intraocular absorption. Corneal spectral transmittance curves which cover the 200–3,200-mμ band were presented. An integration of the corneal transmission in the 700–2,700-mμ band indicates a mean transmission of 43%. Implications for studies of corneal sensibility using infrared stimuli are discussed.

thermal psychophysics; infrared cataract; psychophysiology

Submitted on March 11, 1963
Exposure chamber for animals at changed atmospheric conditions
Authors: Gans P.
Published: December 2017

An airtight exposure chamber is described in which mice can be kept continuously in an atmosphere with a high carbon dioxide percentage, or with a low or high oxygen percentage. Advantages of the apparatus described are the absence of moving parts inside the chamber and, in the experiments with a low or high percentage of oxygen, the absorption of carbon dioxide and water outside the chamber, permitting the continuous treatment of the animals.

animal exposure chamber; carbon dioxide exposure; oxygen exposure

Submitted on January 4, 1963
A new type of electronic cable for chronic implantation in living tissue
Authors: Colwell Robert K.
Published: December 2017

A new type of electronic cable was developed to fill the need for a means of conducting electrical signals through areas of living tissue without disturbing normal function or inducing tissue reaction. The cable consists of a multiconductor braided cable encapsulated in transparent silicone resin. A simple and inexpensive method is described for producing cables of this type with a diameter as small as 1/16 in. Possible applications are found in the field of bioinstrumentation, and in biometric and medical research.

Submitted on February 25, 1963
Relationship between ambient temperature and acetylating capacity of human blood
Authors: Blondheim S. H. , Neumann Gabriel , Kott Edna , Ben-Ishai Zena
Published: December 2017

The ability of human blood to acetylate p-aminobenzoic acid, determined in vitro, varied directly with the ambient temperature to which the subject was exposed before the blood was drawn. This was demonstrated by 135 determinations of the acetylating ability of the blood of 49 subjects performed over a period of 3 years, and also in acute experiments in which subjects were exposed to 6 and 37 C for up to 2 hr. Variations in the acetylating ability of blood may reflect the activity of metabolic mechanisms involved in thermal homeostasis.

aromatic amines; p-aminobenzoic acid; cold; heat acclimatization; (blood) enzymes; weather; environment

Submitted on September 11, 1962
Bilateral differences in forearm blood flow as measured with capacitance plethysmograph
Authors: Hyman Chester , Burnap Donald , Figar ŠtĚpán
Published: December 2017

The electrocapacitance plethysmograph has been modified and tested for the measurement of blood flow through the forearm of normal, resting individuals. Data obtained indicate a small but consistent and significant difference between the blood flow of the two arms of a given individual at any time. This asymmetry is discussed and reasons are presented which make it seem likely that the differences are in blood flow through the skin rather than through muscle. The electrocapacitance plethysmograph was compared with the segmental plethysmograph in careful determinations on a group of subjects and it was found that the apparent blood flow as measured with the segmental plethysmograph tends to decrease as the pressure in the segmental cuff increases and that the differences between the blood flows in the two arms noted above becomes almost impossible to detect with segmental plethysmograph pressures above 15 mm Hg. When the capacitance plethysmograph is compared with the segmental plethysmograph inflated to minimal pressures in a series of acute measurements the correspondence is completely acceptable.

Submitted on December 17, 1962
Threshold Pco2 for respiratory system in acute hypoxia of dogs
Authors: Honda Yoshiyuki , Natsui Teijiro , Hasumura Nariko , Nakamura Keiko
Published: December 2017

Threshold alveolar-arterial Pco2 (PtCOCO2) for the respiratory system in acute hypoxia of anesthetized dogs was examined by observing phrenic nerve discharges. It was found that 1) the lower the alveolar Po2, the lower the PtCOCO2. The relationship between the PaOO2 and the PtCOCO2 was curvilinear, PtCOCO2 showing an abrupt fall in the range of PaOO2 of 30–60 mm Hg. 2) The respiratory drive induced by hypoxia was completely extinguished by lowering alveolar Pco2. Thus it was proved that, during intense hypoxia, respiratory drive continues to be attributable to Pco2 or cH, even when they have been reduced far below normal. 3) Ventilatory response related to the hypoxic drive with other parameters constant was calculated from the nonhypoxic and hypoxic PtCOCO2 differences and from the ventilatory coefficients. It was then inferred that a positive interaction between Po2 and Pco2 or cH stimulus for ventilation exists when PaOO2 falls below about 70 mm Hg.

Pco2 levels in acute hypoxia; dogs
Some effects of vibration on totally immersed cats
Authors: Pape R. W. , Becker F. F. , Drum D. E. , Goldman D. E.
Published: December 2017

A survey has been made of the physiological and pathological changes occurring when anesthetized totally immersed cats are exposed to vertical sinusoidal vibration. Twenty-five of 55 cats survived exposure to 15 G peak acceleration for periods averaging 47 min. A decrease in peak acceleration from 15 to 10 G caused a large decrease in mortality. Time of exposure, within the limits of 5–120 min, also affected mortality, but much less strikingly than acceleration. The heart rate and mean respiratory rate are little changed during severe vibration. Respiration becomes irregular, and the tidal volume is greatly depressed. At 15 G peak acceleration, electrocardiographic changes of ischemia and injury occur, especially in those cats which die later. The most significant gross pathological findings are pulmonary collapse and hemorrhage, involving especially the peripheral parts of the lower lobes, and gastrointestinal hemorrhage. The major changes appear to be related to vascular change, either by rupture, leakage, or changes in tone. The resulting ischemia contributes to tissue damage and death. There is both clinical and pathological correlation between the intensity of the forces applied and the response.

vertical sinusoid vibration; gravity acceleration; heart rate; respiration

Submitted on August 27, 1962
Measurement of lung diffusing capacity by means of C14O in a closed system
Authors: S⊘lvsteen Paul
Published: December 2017

A method of measuring the lung diffusing capacity (Dl) with radioactive carbon monoxide (C14O) and nonuniformity of ventilation with nonabsorbable gas in a closed system is described. Treating ventilation as a continuous phenomenon and disregarding dead space, the mathematical equations for uniform and nonuniform ventilation (two lung regions ventilated in parallel) are derived. It is proved that sooner or later the curve for carbon monoxide, plotted on semilogarithmic paper, will be rectilinear. Experiments in six normal subjects and eight patients with chronic lung disease are described. Determinations of the distribution of the ventilation and the Dl are made in separate experiments. Since the method is unreliable at high Dl values, many of the Dl estimations are performed at high oxygen tension, which reduces the apparent Dl. It is shown that the assumption of a uniform distribution of Dl to lung volume explains the experimental findings better than the assumption of a uniform distribution of Dl to alveolar ventilation. Dl was decreased in four of the eight patients.

mathematics of uniform and nonuniform ventilation; distribution of lung diffusing capacity in relation to lung volume and alveolar ventilation; N2 curve for use in calculating alveolar ventilation and regional lung volumes; CO curve for use in calculating lung diffusing capacity; diffusing capacity of lung determined with a closed system

Submitted on October 15, 1962
Measurement of factors impairing gas exchange in man with hyperbaric pressure
Authors: Lenfant C.
Published: December 2017

Alveoli with very low ventilation/perfusion ratios (Va/Q) contribute capillary blood with venous saturation to the mixed arterial stream. The portion of the alveolar arterial oxygen difference (A-a Do2) due to these units with very low Va/Q ratios cannot be differentiated from that due to an anatomical shunt at ambient pressures. By raising the barometric pressure to such a level that venous blood is saturated, the O2 dissociation curve no longer affects the A-a Do2 measurement, and the differentiation can be made. In the present experiments 75% O2 was inspired at sea level and at a depth equivalent to 2.6 atm. The A-aD was measured for O2, CO2 and N2. In seven out of eight subjects A-a Do2 and A-a Dn2 varied when the barometric pressure was increased. A theoretical analysis showed that the results can be interpreted on the basis of a bimodal distribution of Va/Q composed of a large group of well-ventilated alveoli and of a small group of units having an undeterminable Va/Q. The shunt calculated from the total A-a Do2 at sea level was 3.47% of the total cardiac output. When the A-a Do2 due to Va/Q (i.e., A-a Dco2 + A-a Dn2) was subtracted from the total A-a Do2 the shunt was 1.78%. At 2.6 atm that part of the total A-a Do2 found to be due to shunt was 0.8%, or 25% of the shunt estimated at sea level from the pure O2 technique.

pulmonary shunts; ventilation/perfusion distribution; diving; hyperbarism

Submitted on June 24, 1963
Reflex control of abdominal muscles during positive-pressure breathing
Authors: Bishop Beverly
Published: December 2017

Continuous positive-pressure breathing initiates expiratory activity in the abdominal muscle and inhibits the diaphragm in anesthetized cats. This investigation defines neural mechanisms involved in this abdominal muscle response (AMR) to positive-pressure breathing. The AMR is not a segmental reflex since it is abolished by thoracic spinal transection. Bilateral rhizotomy (T8-L3) also eliminates AMR, but laparotomy and abdominal evisceration do not, suggesting that some neural inflow other than from abdominal muscle or viscera is necessary but insufficient for maintaining AMR. Abdominal vagotomy failed to interrupt AMR which was abolished by bilateral cervical vagotomy, indicating that the necessary receptors lie in the thorax. Compression or local anesthesia of the cervical vagi provided the experimental means for abolishing either the inhibition of the diaphragm or the AMR without necessarily interrupting the other. That one response may persist in the absence of the other indicates that vagal afferent pathways subserving AMR are distinct from those mediating diaphragm inhibition. Hence the active expiration of pressure breathing is not a simple corollary of the Hering-Breuer inflation reflex but is a separate reflex served by its own vagal pathway.

abdominal muscle response; vagus control of active expiration; abdominal muscle motoneuron pool; vagal afferent pathway in pressure-breathing reflex; thoracic receptors; diaphragm response to pressure breathing; diaphragm; inspiration; expiratory reflexes; inspiratory reflexes; respiratory reflexes; segmental reflexes; spinal reflexes

Submitted on February 21, 1963
Nature of purines excreted in urine during muscular exercise
Authors: Nasrallah Salah , Al-Khalidi Usama
Published: December 2017

The purines which were previously noted to increase in the urine during muscular exercise have been identified as hypoxanthine and xanthine. Quantitative studies on 11 human subjects showed that the magnitude of the increase in excretion of hypoxanthine varied greatly and reached up to 20-fold in some cases. The increase in the excretion of xanthine was less pronounced with the maximum about threefold.

xanthine and hypoxanthine excretion

Submitted on August 8, 1963
Effects of aspartic acid salts (Mg and K) on swimming performance of rats and dogs
Authors: Matoush Le Roy O. , Consolazio C. Frank , Nelson Richard A. , Isaac Gerhard J. , Torres Juan B.
Published: December 2017

Five separate experiments were performed to evaluate the effects, if any, of Mg and K salts of aspartic acid on the swimming times of rats and dogs. Experiments 1 and 2 were with rats doing a single swim-to-exhaustion in water maintained at 17 C and 25 C. In experiment 3 dogs performed a single swim-to-exhaustion in 17 C water. During the first three experiments each animal underwent two treatments; a no-treatment control, and an aspartate therapy. Experiment 4 was a long-term single swim-to-exhaustion test. The rats were divided into two groups: one group receiving a placebo and the other group receiving aspartate. Each group swam to exhaustion in 25 C water twice a week for 6 weeks. Experiment 5 was of the same experimental design as experiment 4 with the exception that a double swim-to-exhaustion was used to measure performance. Statistical analysis of the mean swimming times for both rats and dogs in the five experiments showed that average swimming times under control and aspartate therapy were not significantly different.

exercise; ergogenic drugs; swimming time to exhaustion endurance criterion

Submitted on May 8, 1963
Thin-layer chromatography of component A of the menstrual stimulant
Authors: Clitheroe H. J.
Published: December 2017

Thin-layer chromatography has been adapted to separate material of high biological potency from much of the inactive material contained in component A of the menstrual stimulant. The chromatoplates were developed with solvent mixture of chloroform, methanol, and water (60:10:1). Visualization of the spots was carried out by various methods; ultraviolet fluorescence of the charred material appeared to be the most sensitive. Samples of ricinoleic and phloionolic acids were used as reference standards. The biological active material of the component A preparations always ran just in front of phloionolic acid. Menstrual fluid was collected in vaginal cups; total volume and crude liquid extract measurements were also carried out on the fluid.

uterine smooth muscle stimulant; menstrual flow rates

Submitted on October 1, 1963
Gaseous diffusion from alveoli into pulmonary arteries
Authors: Jameson A. Gregory
Published: December 2017

In 40 patients, during right heart catheterization a catheter with a platinum tip electrode was wedged in a branch of the pulmonary artery. With the electrode acting as part of a potentiometer, signals were recorded following single inhalations of hydrogen. Similarly signals were recorded following inhalations of oxygen with the electrode acting as part of a polarograph. With either gas, signals were recorded appearing in less than 1 sec after the gas entered the nose. The signals paralleled the changes in the alveolar concentration of the gas. The infusion of dextrose through the wedged catheter or the withdrawal of the catheter a short distance from the wedged position, did not significantly affect the results. The inhaled gas was also shown to appear at the tip of the wedged catheter significantly before it appeared in the descending aorta. It is concluded that the observations made are evidence of diffusion of the inhaled gases from the alveoli directly into the pulmonary arteries.

platinum/hydrogen anode; oxygen polarograph; alveolo-arterial oxygen diffusion; alveolo-arterial hydrogen diffusion

Submitted on May 29, 1963
Fibrinolytic activity and muscular exercise in heat
Authors: Bedrak E. , Beer G. , Furman K. I.
Published: December 2017

The fibrinolytic activity of whole blood is increased by exposure to environmental heat stress. The increased fibrinolytic activity of muscular exercise is further increased if the muscular activity is performed in heat. In resting or exercising subjects who are heat acclimatized, the increased fibrinolytic activity due to heat exposure is less than that which occurs in the unacclimatized state.

fibrinolysis and heat acclimatization in man; heat stress, exercise, and blood fibrinolytic activity

Submitted on September 4, 1963
d-Aldosterone and sweat electrolytes
Authors: McConahay T. P. , Robinson S. , Newton J. L.
Published: December 2017

Men worked (BMR 190 kcal/m2 hr) in the heat (45–50 C D.B.; 26 C W.B.) for periods of 5–7 hr, maintaining water and salt balance by drinking appropriate saline solutions. d-Aldosterone was administered by continuous intravenous infusion at 1.5 µg/kg hr during the third to seventh hours without altering the Na or Cl concentration of the men's sweat from control values determined during the first 2 hr of the exposures, or from the values observed during separate control experiments. Na and Cl concentrations of sweat secreted the day following the infusion experiments were not significantly different from those of samples collected the day after control experiments. The sodium-conserving responses of the men's sweat glands 7–24 hr following salt depletion (-140 to -230 mEq) were not significantly altered by infusion of 2.0–4.5 µg/kg hr of d-aldosterone. Continuous infusion of d-aldosterone at 1.8 µg/kg hr into one brachial artery did not alter the Na or Cl concentration of sweat being secreted by the infused arm, either from simultaneously collected samples from the man's other arm or from control values in both arms before the infusion was started. In all cases, pronounced reductions in urinary Na:K ratios were observed during and after d-aldosterone administration.

Submitted on October 28, 1963
Ventilatory mechanics in hypovolemic shock
Authors: Cahill John M. , Byrne John J.
Published: December 2017

In order to study ventilatory mechanics in shock, dogs were bled arterially into a reservoir, the height of which was regulated to keep the mean blood pressure of the animal at approximately 30 mm Hg. When the animal “took up” 40% of his maximal shed volume of blood (2–3 hr), the remainder of the blood was reinfused and the animal assumed to be in irreversible shock. Studies throughout the stages of hypovolemic and irreversible shock revealed a significant rise in lung compliance and a fall in combined viscous and air-flow resistance initially if the animal's lungs were carefully inflated prior to each study. As shock continued, there was a tendency for the lung compliance and resistance to air flow to return in the direction of the control values.

Submitted on October 29, 1962
Recording viscometer for nonhomogeneous biological fluids
Authors: Dworkin B. R. , Wolach A. , Necheles H.
Published: December 2017

Viscosity of secretions can change quickly from very thin to rather viscid consistency, and available viscometers cannot provide specific information on each fraction of mixed specimens. For this reason we are describing a viscometer that determines the entire viscosity spectrum of a given sample of secretion. The instrument registers the rate of flow of each aliquot of a fluid as it passes through a short narrow-gauge tube under constant pressure. The fluid is driven out of a syringe by a servo-controlled drive mechanism, and through a manifold (1 ml volume) to which a pressure transducer and a hypodermic needle are attached. The pressure in the manifold is kept constant by an electronic feedback loop. A permanent-magnet motor is coupled to the d-c drive motor of the syringe, producing an electric signal proportional to the drive velocity. The instrument has been in satisfactory use for 1 year.

biological servo-mechanisms; biological analog computer; hydraulic analog computer; nonhomogeneous viscosities

Submitted on November 12, 1963
Pressure-volume studies on lung lobes in man
Authors: Ishikawa Koh , Martin C. J. , Young A. C.
Published: December 2017

This study has sought to measure pressure differences occurring within the chest cavity and some of the mechanical properties of lung lobes. One lobe in the hemithorax has been used as an intrapleural pressure capsule by blocking it with a catheter and balloon system. After insertion of an esophageal, a bronchospirometric, and a lobar pressure-measuring catheter, the interrupted vital capacity maneuver has been used to compare pressures within the lungs and esophagus. Pressure differences, which increased as lung volumes increased, were found between lobes, and between lobes and esophagus. Esophageal pressure swings were of lower magnitude than lobar pressure swings. Esophageal pressure was neither linearly related to lobe pressure nor a mean pressure for the hemithorax. Thus, lung volume is not a function of a single pressure within the chest, and the concept of the commonly used pressure-volume curve is oversimplified.

mechanical properties; pressure capsules

Submitted on October 18, 1963
Effect of environmental temperature on hamster body fat composition
Authors: Kodama Arthur M. , Pace Nello
Published: December 2017

Body fat content and the melting point and fatty acid composition of body fat of hamsters exposed to 35, 27, 20, 15, 10, and 6 C for 2 weeks were determined. The relationship between exposure temperature and body fat content and composition resembled that between environmental temperature and metabolic rate. Below the critical temperature, there was a progressive decrease in total body fat content and melting point accompanied by a decrease in the mole fraction of palmitic acid and an increase in the mole fraction of oleic acid. The softening of body fat in cold-exposed animals appears to be the result of an increased mobilization of depot fat in response to a higher metabolic rate in the cold, a mobilization which is at least partially selective with respect to individual fatty acids or triglycerides. Examination of changes in whole body composition revealed that 72% of the loss in body weight of hamsters exposed to 6 C was due to a decrease in body fat content. In contrast, the decrease in body fat content accounted for only 28% of the body weight loss of pair-fed hamsters kept at 27 C on reduced caloric intake to match the body weight loss experienced by cold-exposed animals. It appears, therefore, that cold exposure induces a more effective fat depot mobilization than does reduced caloric intake.

heat exposure; cold exposure; body composition

Submitted on February 3, 1964
pH-temperature conversion factors and pCO2 factors for hypothermia
Authors: Austin William H. , Lacombe Eleanor H. , Rand Peter W.
Published: December 2017

The change in pH per degree centigrade was re-evaluated in a series of normal and ill adults. The results indicate that the ΔpH per degree centigrade is relatively constant in a given individual and of the order of -.015 for every degree increase in the temperature. Errors in hypothermic work may be minimized by using a water-bath setting midway between the highest and the lowest temperatures anticipated. These findings tend to support previous figures in both magnitude and range. Procedural accuracy is emphasized and technical difficulties in pH measurements are suggested as possible sources of disagreement raised by one investigator. "pCO2 factors" are given for temperatures from 20 to 38 C for rapid calculation of pCO2 from CO2 content and pH corrected for temperature.

CO2, partial pressure conversion factors in hypothermia; hypothermia, pH, and pCO2 factors; acid-base metabolism and hypothermia

Submitted on October 25, 1963
Lung volumes and breathing patterns in wind-instrument players
Authors: Bouhuys Arend
Published: December 2017

Pulmonary function at rest and physiological performance during play was studied in 42 professional wind players on 15 different instruments. Vital capacity was larger than expected from age and height in all brass players. Other lung function results were similar to or better than those in control subjects. Breathing patterns are qualitatively similar in players of nearly all instruments; rapid and deep inspirations are followed by prolonged expirations through the instrument. In some instruments nearly the whole vital capacity may be used during play. No gross changes in arterialized capillary blood pH, Pco2 and standard bicarbonate content occurred during frac12 hour's play. Mouth pressure on most instruments increased both with pitch and loudness and varied from 2.5 to 158 mm Hg. Air flow rates varied from less than 0.05 to over 1.6 liters/ sec. Performance on some, mainly brass, instruments is limited mechanically; on others, e.g., the oboe, breath-holding time is the limiting factor. Energy expended on the instrument (mouth pressure times flow rate) ranged from less than 0.1 up to 17 w.

pulmonary function; respiratory mechanics

Submitted on January 13, 1964
Measurement of upper and lower airway resistance and conductance in man
Authors: Blide Richard W. , Kerr H. David , Spicer William S.
Published: December 2017

The resistances to flow in the upper (Ruaw) and lower (Rlaw) airway of human lungs were measured simultaneously with total airway resistance (Raw) and the volume of thoracic gas (Vtg) using the plethysmographic method and lateral pressure taps at the tracheal and oral levels. Ruaw is found to decrease slightly in a curvilinear fashion with increasing Vtg while its reciprocal, Guaw, is linearly related to Vtg with a negative Vtg intercept in normal subjects. Lower airway conductance (Glaw) is linearly related to Vtg with a slope of approximately 1.0 liters/sec per cm H2O per liter. From the partitioned resistances it is deduced that total airway conductance (Gaw) is curvilinear but approximately linear over the majority of the Vtg. A method of calculating resistance and conductance in the upper and lower airways from Raw versus Vtg data is presented using the equation Raw = Vtg/(A @#X002B; B Vtg) where B2/A @#X003D; dGlaw/ dVtg. Three hundred and sixty-two records of Raw versus Vtg data from 22 normal, asthmatic, and bronchitic subjects are then evaluated by this method and the results compared to those obtained by direct measurement.

intrathoracic or lower airway conductance; intrathoracic or lower airway resistance; extrathoracic or upper airway conductance; extrathoracic or upper airway resistance

Submitted on November 8, 1963