Ferrokinetics: a biologic model for plasma iron exchange in man

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Abstract

A method is presented for calculating internal iron kinetics. An early reflux associated with extravascular exchange and a late reflux associated with erythropoiesis are described. A biologic model of iron exchange is proposed in which erythron iron turnover is divided into an effective portion (iron fixed in circulating red cells) and wastage iron of erythropoiesis (late reflux). Nonerythroid iron exchange also has a fixed portion (parenchymal uptake) and an early reflux (lymphatic circuit), both of which correlate in amount with the amount of plasma iron. Ferrokinetic measurements in normal subjects and in various pathologic states are presented to validate the model.

Authors

J. D. Cook, G. Marsaglia, J. W. Eschbach, D. D. Funk, C. A. Finch

The effect of sodium taurocholate on the hepatic metabolism of sulfobromophthalein sodium (BSP). The role of bile flow

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Abstract

The influence of bile salts on the hepatic metabolism of sulfobromophthalein sodium (BSP) was studied in the perfused rat liver. During sodium taurocholate infusions, hepatic uptake of BSP from plasma was increased and appeared to be related to an enhanced transit of BSP from liver into bile. BSP-glutathione conjugation was not affected by the bile salt infusions, although bile salts inhibited the enzyme system in vitro.

Authors

J. L. Boyer, R. L. Scheig, G. Klatskin

Gargoylism: hydrolysis of β-galactosides and tissue accumulation of galactose- and mannose-containing compounds

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Abstract

The sugars present in hydrolyzed extracts of human liver and brain were analyzed by gasliquid chromatography after conversion to their alditol acetates. The samples analyzed were obtained from control subjects, patients with gargoylism, and patients with a few other kinds of storage disorders. Accumulation of galactose was demonstrated in the liver and the brain of two patients with gargoylism, and in the liver samples, high levels of mannose were found too. We also studied the hydrolysis of a number of galactosides by homogenates from different tissues in the control subjects and in the patients. Separation methods and kinetic studies demonstrated the presence in normal human tissues of two different β-galactosidases, which we call enzyme A and enzyme B, respectively. Enzyme A hydrolyzed all the β-galactosides tested. Enzyme B hydrolyzed the synthetic substrates tested (4-methylumbelliferyl-, p-nitrophenyl-, o-nitrophenyl-, and phenyl-β-galactoside) but not the natural substrates tested (ceramide-β-galactoside, ceramide lactoside, transferrin glycopeptide, and keratan sulfate). Enzyme B also exerted β-glucosidase activity. In various tissues from patients with gargoylism, deficiency of β-galactosidase A could be demonstrated.

Authors

Björn Hultberg, Per-Arne Öckerman, Arne Dahlqvist

The role of skin and muscle resistance vessels in reflexes mediated by the baroreceptor system

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Abstract

The role of skin and muscle vascular beds in baroreceptor-mediated alterations of peripheral vascular resistance was evaluated in six normal subjects in whom the skin circulation in one forearm was temporarily suppressed by epinephrine iontophoresis. Baroreceptor activity was enhanced by application of negative pressure to the neck (neck suction) and inhibited by application of lower body negative pressure. Forearm blood flow was measured simultaneously in both arms with strain gauge plethysmographs. Since blood flow in the treated arm consisted entirely of muscle flow, skin flow was calculated from the difference between total forearm flow in the intact arm and muscle flow in the treated arm. Vascular resistances were calculated as the ratio of mean arterial pressure to the blood flow of each vascular bed. During neck suction, mean arterial pressure decreased from an average of 89 to 75 mm of Hg (P < 0.005), heart rate decreased from an average of 60 to 55 beats/min (P < 0.005), and total skin and muscle flows remained essentially unchanged. Cutaneous vascular resistance decreased from an average of 75 to 49 mm of Hg/ml per 100 g per min (P < 0.05), muscle vascular resistance from 68 to 51 (P < 0.005), and total forearm vascular resistance from 36 to 24 (P < 0.025). During lower body negative pressure, heart rate increased from an average of 59 to 69 beats/min (P < 0.005), mean arterial pressure did not change significantly, and significant decreases occurred in forearm blood flow from 5.4 to 2.7 ml/100 g per min, in skin blood flow from 3.1 to 1.4, and in muscle blood flow from 2.3 to 1.3. Cutaneous vascular resistance increased from an average of 47 to 110 mm of Hg/ml per 100 g per min (P < 0.05), muscle vascular resistance from 43 to 72 (P < 0.005), and total forearm vascular resistance from 20 to 38 (P < 0.001). These results demonstrate that both the skin and muscle resistance vessels participate in reflex changes initiated by alterations in baroreceptor activity.

Authors

G. David Beiser, Robert Zelis, Stephen E. Epstein, Dean T. Mason, Eugene Braunwald

Effects of controlled interruption of the enterohepatic circulation of bile salts by biliary diversion and by ileal resection on bile salt secretion, synthesis, and pool size in the rhesus monkey

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Abstract

The effects of controlled interruption of the enterohepatic circulation (EHC) of bile salts by biliary diversion on bile volume, bile salt secretion and synthesis rates, bile salt pool size, and the relationship to fecal fat excretion were studied in 16 rhesus monkeys.

Authors

R. Hermon Dowling, Eberhard Mack, Donald M. Small

Influence of bolus temperature on human esophageal motor function

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Abstract

Hot and cold water, in comparison to room temperature water, ingested by normal young men, profoundly alters esophageal motor function. Cold water slows or abolishes esophageal peristalsis, prolongs the contraction wave in the distal esophagus, produces a delayed but prolonged relaxation of the lower esophageal sphincter, and regularly causes a lower esophageal sphincteric contraction of increased amplitude. It does not, however, diminish the frequency of response of the lower esophageal sphincter even when the peristaltic wave above is abolished. Hot water, on the other hand, accelerates the response of the esophagus to the swallow; this change is reflected by increased speed of wave propagation, waves of shorter duration, a more brief relaxation of the lower esophageal sphincter, and a lower esophageal sphincter contraction of less amplitude. Hot water may even increase the frequency of peristalsis at least in the proximal esophagus. In spite of these changes, however, neither extreme of temperature altered the rapid passage of the water swallows through the more proximal portions of the esophagus. Hot water tended to traverse the lower esophageal sphincter more rapidly than did room temperature water, but cold water was often delayed in entering the stomach and tended to pool in the distal esophagus even though sphincteric relaxation was manometrically complete and prolonged.

Authors

D. H. Winship, S. R. Viegas De Andrade, F. F. Zboralske

Intraglomerular fibrin, platelet aggregation, and subendothelial deposits in lipoid nephrosis

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Abstract

We have investigated the formation of fibrin, platelet aggregates, and subendothelial deposits in lipoid nephrosis. Fibrin formation was found in 10 cases of active lipoid nephrosis. Platelet aggregates were found in eight cases and subendothelial deposits in nine. Fibrin and platelets were also found in cases of nephrotic syndrome due to other causes, and in glomerulonephritis. Fibrin was generally absent in lipoid nephrosis in remission and in benign recurrent hematuria. It is suggested that what seems to be a lower incidence in females is more apparent than real and that fibrin or related material may be present in a less easily identifiable form. Steroid therapy apparently had no effect on the presence or absence of fibrin. Most instances were associated with elevated serum cholesterol and α2-globulin. It is suggested that elevated serum lipids as well as the disease process in the kidney play a role in this phenomenon. It is further suggested that intraglomerular fibrin formation could lead to irreversible renal damage in lipoid nephrosis.

Authors

John L. Duffy, Thomas Cinque, Edith Grishman, Jacob Churg

Responses of saphenous and mesenteric veins to administration of dopamine

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Abstract

Others have observed that dopamine (3,4-dihydroxyphenylethylamine) constricts resistance vessels in skin, but dilates these vessels in the mesentery. We studied the effects of dopamine on cutaneous and mesenteric veins of dogs to see if this agent also produced qualitatively different effects on the tone of capacitance vessels (veins) in these vascular beds. The lateral saphenous or the left colic vein was perfused at constant flow with blood from a femoral artery. Pressures at the tip of the perfusion cannula and at the tip of a catheter 15 cm downstream were recorded continuously. Increases in the pressure gradient between these two points indicated venoconstriction; decreases indicated venodilatation. Dopamine and norepinephrine injected into the perfusion tubing caused constriction of both veins. The constriction was antagonized by blockade of alpha receptors. A dilator action of dopamine was not seen, even after alpha receptor blockade or in the presence of increased venous tone produced by serotonin, norepinephrine, or nerve stimulation. Reserpine and cocaine did not alter responses to dopamine in the saphenous vein; this suggests that the venoconstrictor action of dopamine results mainly from a direct effect on alpha receptors and that uptake into sympathetic nerve endings may not be important in regulating the amount of dopamine available to receptors in the saphenous vein.

Authors

Allyn L. Mark, Tetsuji Iizuka, Michael G. Wendling, John W. Eckstein

A new method for the measurement of acute alterations in thyroxine deiodination rate in man

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A newly devised dual labeled iodine isotopic method is described for the detection and quantitation of alterations in thyroxine (T4) deiodination rate in man. This method employs the principle of a constant 125I infusion to serve as a reference source for the generation of 131I derived from the deiodination of T4-131I. Measurement of these two iodide isotopes are made in serially timed urine collections and are expressed in terms of a ratio value. Using this technique, it was possible to measure accurately the effects of a single dose of 6-propylthiouracil (6-PTU) in producing inhibition of T4 deiodination in euthyroid subjects. It was also possible to assess the time of onset, duration of action, and degree of inhibition produced by 6-PTU. Employing single doses of 6-PTU, ranging from 100 to 1000 mg, there was found to be a log dose relationship with a degree of inhibition observed in T4 deiodination. In control studies T4 deiodination rate was found to be constant for periods ranging up to 72 hr in normal ambulating subjects. The acute administration of many other agents was employed in an attempt to alter the T4 deiodination rate. These included diphenylhydantoin, methimazole, triiodothyronine, thyroxine, thyroid stimulating hormone (TSH), adrenocorticotropin (ACTH), hydrocortisone, predinsolone, potassium iodide, epinephrine, and oxytocin. No detectable change in T4 deiodination rate was observed with these agents in the dosage ranges employed in this study. The lack of any observable alteration in the T4 deiodination rate in response to this array of drugs and hormones appears to indicate that the availability of T4 to intracellular sites of deiodination and possibly action is well modulated to resist abrupt changes.

Authors

John T. Nicoloff

Increased Vascular permeability produced by human platelet granule cationic extract

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Abstract

A cationic protein extract obtained from isolated human platelet granules increased vascular permeability in mouse and rabbit skin. The permeability-enhancing effect was not inhibited by soybean trypsin and pancreatic trypsin inhibitor, methylsergide maleate, carboxypeptidase B, and C[unk]1 inactivator. Permeability-enhancing activity was blocked by prior treatment of challenged animals with antihistamine. The nondializable relatively heat-stable cationic granule protein extract possessed potent mastocytolytic activity. The experiments described suggest that human platelets exert a permeability-enhancing effect by lysosomal release of cationic proteins which cause histamine release from adjacent tissue mast cells.

Authors

Ralph L. Nachman, Babette Weksler, Barbara Ferris

Hemodynamic effects of ventricular defibrillation

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Abstract

Hemodynamic responses to ventricular defibrillation were studied in anesthetized dogs. Observations were made on arterial, right atrial and left ventricular end-diastolic pressures, on cardiac output (dye dilution), heart rate, and right atrial electrocardiogram. Ventricular fibrillation was induced electrically with a bipolar electrode catheter placed in the right ventricle. Fibrillation was maintained for 15 or 30 sec and terminated with a 400 w sec capacitor discharge across the thoracic cage.

Authors

Donald G. Pansegrau, François M. Abboud

Autonomic reflexes and vascular reactivity in experimental scurvy in man

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Abstract

Ascorbic acid is a required cofactor in the conversion of dopamine to norepinephrine in vitro, and the deficiency of this vitamin in guinea pigs is associated with degeneration of autonomic ganglion cells and with cardiac supersensitivity to norepinephrine. Because of these findings, we tested the hypothesis that ascorbic acid deficiency in man alters autonomic cardiovascular reflexes and vasomotor responses to adrenergic stimuli. We studied five normal volunteers who had been deprived of ascorbic acid for a period of 3 months; they had developed symptoms and signs of scurvy and their plasma levels of ascorbic acid averaged 0.178 ±SE 0.07 mg/100 ml. We repeated the studies after giving the subjects vitamin C for a period of 4 months; they had become asymptomatic and their plasma ascorbic acid had increased to an average of 1.68 ±0.151 mg/100 ml.

Authors

François M. Abboud, James Hood, Robert E. Hodges, Howard E. Mayer

Characterization of human anti-glomerular basement membrane antibodies eluted from glomerulonephritic kidneys

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Abstract

Eluates from glomerulonephritic kidneys of nine patients with anti-glomerular basement membrane (anti-GBM)-mediated nephritis were studied to define their antigenic specificity and content of kidney-fixing antibodies. Five of these patients had Goodpasture's syndrome with pulmonary and renal involvement clinically; four patients did not. All had in vivo fixation of IgG in the characteristic linear pattern by direct immunofluorescence, and eluted IgG fixed to normal human kidney sections. Eluates from kidneys of patients with Goodpasture's syndrome fixed more frequently to homologous nonglomerular renal and extrarenal antigenic sites and to heterologous GBM than did non-Goodpasture eluates over a hundredfold range of antibody concentrations; both could be blocked by prior absorption with soluble GBM antigens. By radial immunodiffusion and precipitation tests the content of IgG in the eluates was measured to range from 2 to 20% of the total protein eluted. By paired label isotopic fixation studies with some of the eluates the per cent of IgG that was kidney fixing ranged from 0.6 to 23.4%. Although the in vivo fixation studies with radiolabeled eluates failed to indicate significant fixation to monkey lung, the observations define quantitative as well as qualitative differences between anti-GBM antibody populations mediating the Good-pasture syndrome compared to those causing glomerulonephritis without lung involvement.

Authors

J. J. McPhaul Jr., Frank J. Dixon

Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes

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Abstract

Ion-exchange calcium electrodes represent the first practical method for the direct measurement of ionized calcium [Ca++] in biologic fluids. Using both “static” and “flow-through” electrodes, serum [Ca++] was within a rather narrow range: 0.94-1.33 mmoles/liter (mean, 1.14 mmoles/liter). Within a given individual, [Ca++] varied only about 6% over a several month period. Consistent pH effects on [Ca++] were observed in serum and whole blood, [Ca++] varying inversely with pH. Less consistent pH effects were also noted in ultrafiltrates, believed to largely represent precipitation of certain calcium complexes from a supersaturated solution. Heparinized whole blood [Ca++] was significantly less than in corresponding serum at normal blood pH, related to the formation of a calcium-heparin complex. [Ca++] in ultrafiltrates represented a variable fraction (66.7-90.2%) of total diffusible calcium. There was no apparent correlation between serum ionized and total calcium concentrations. Thus, neither serum total calcium nor total ultrafiltrable calcium provided a reliable index of serum [Ca++]. Change in serum total calcium was almost totally accounted for by corresponding change in protein-bound calcium [CaProt]. About 81% of [CaProt] was estimated to be bound to albumin and about 19% to globulins. From observed pH, serum protein, and [CaProt] data, a nomogram was developed for estimating [CaProt] without ultrafiltration. Data presented elsewhere indicate that calcium binding by serum proteins obeys the mass-law equation for a monoligand association. This was indicated in the present studies by a close correspondence of observed serum [Ca++] values with those predicted by the McLean-Hastings nomogram. While these electrodes allow study of numerous problems not possible previously, they have not been perfected to the same degree of reliability obtainable with current pH electrodes. The commercial (Orion flow-through) electrode is: (a) expensive. (b) requires periodic replacement of membranes, and (c) has not yet been thermostated. As with blood pH measurements. (d) electrode response is logarithmic, i.e. small potential errors generate rather large [Ca++] errors. (e) loss of CO2 should be prevented, and (f) errors due to other cations must be considered under certain conditions. Despite these limitations, we believe the electrode represents a major advance in calcium metabolism.

Authors

Edward W. Moore

Pulsatile uptake of CO in the human lung

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Abstract

The instantaneous uptake of CO in the lungs was measured with a water-filled body plethysmograph in normal man. First, control measurements of plethysmograph pressure were made while the subject held his breath for 7 sec after breathing gas mixtures prepared to bring his alveolar PO2 and PCO2 close to mixed venous levels. Then, CO uptake measurements were made while he held his breath after inhaling the same gas mixtures with added CO (2.0%). The change in lung volume on CO minus the change in lung volume during the control measurement was a measure of the CO uptake in the lungs. Cardiopneumatic changes in lung gas volume were subtracted electrically. All of five subjects showed pulsatile CO uptake. The mean CO uptake was 103 ml/min. A peak uptake of 2.0 (range 1.6-2.3) times the mean uptake occurred 0.3-0.4 sec after the R wave of the EKG and a minimum uptake of 0.4 (range 0.2-0.5) times the mean uptake occurred during the tenth of a second before the R wave of the EKG. These results suggest that pulmonary capillary blood volume is pulsatile during the cardiac cycle.

Authors

Harold A. Menkes, Kazuaki Sera, Robert M. Rogers, Richard W. Hyde, Robert E. Forster II, Arthur B. DuBois

Long-term decay of serum cholesterol radioactivity: body cholesterol metabolism in normals and in patients with hyperlipoproteinemia and atherosclerosis

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Abstract

After the intravenous injection of labeled cholesterol, the decay of specific radioactivity of total serum cholesterol was studied in 12 patients for 15-63 wk (average, 45 wk). In some, but not all of the patients studied, the slow slope of the decay curves suggested a deviation from monoexponential behavior, and the data of the slow period of the decay of specific activity were curve fitted by two exponentials. Six patients had serum lipid values regarded as normal and six had hyperlipoproteinemia. The data were analyzed by input-output analysis and yielded the following results. Values for the input rate of cholesterol (IT) (the sum of dietary and biosynthesized cholesterol) showed no difference between the normals and patients with hypercholesterolemia. The size of the rapidly miscible pool of cholesterol (Ma) was significantly higher in the group of hypercholesterolemic patients partly due to increased serum cholesterol levels. The size of the total exchangeable body mass of cholesterol (M) was higher by an average of 49 g in the patients with hypercholesterolemia as compared to normals. The remaining exchangeable mass of cholesterol (M — Ma) of the hypercholesterolemic subjects was higher by an average of 29 g as compared to normals. These differences were statistically significant.

Authors

Paul Samuel, William Perl

Experimental myocardial infarction: VI. Efficacy and toxicity of digitalis in acute and healing phase in intact conscious dogs

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Abstract

Use of digitalis in myocardial infarction is controversial. To determine the efficacy and toxic threshold, serial infusions of 3 μg/kg per min of acetyl-strophanthidin were given to six intact conscious dogs 24 hr before and 1 hr, 2 days, and 7 days after myocardial infarction induced by inflation of a balloon cuff implanted on the left anterior descending coronary artery. Within 1 hr after myocardial infarction, heart rate increased by 28%. Left ventricular end-diastolic pressure increased from 7 to 20 mm Hg, and stroke volume decreased by 25%. At this time acetylstrophanthidin caused no beneficial hemodynamic change, 1 wk later, the heart rate and left ventricular end-diastolic pressure had declined toward normal but remained elevated. At this time, acetylstrophanthidin lowered left ventricular end-diastolic pressure by 25%, and increased the stroke volume and cardiac output by 25% and 21% respectively, without any change in heart rate or aortic pressure. Tolerance to acetylstrophanthidin, defined as appearance of ventricular tachycardia, declined the 1st hr after myocardial infarction by 24% (P<0.05) from the control level of 43 ±4 μg/kg (SEM), but subsequently returned to control.

Authors

Raj Kumar, William B. Hood Jr., Julio Joison, David P. Gilmour, John C. Norman, Walter H. Abelmann

A new method for isolating the nonidentical protein subunits of human plasma α-lipoprotein

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Abstract

Human plasma alpha lipoprotein (αLP) was totally delipidated by gel filtration on Sephadex LH-20 in a medium of 2 butanol:acetic acid:H2O, 4:1:5. The resulting alpha protein (αP) exhibited two major bands, labeled C and D, on acrylamide-gel electrophoresis in 5.0 M urea at pH 8.8 or 4.0. Minor bands labeled A and B, also present, were shown to be aggregates of C which form when the latter is lyophilized. The C and D components were isolated in pure form from αP (prepared by LH-20 chromatography of αLP) by gel filtration of this protein on Sephadex G-200 in a medium of 1.0 N acetic acid: the C component emerged with a distribution coefficient (Kd) of 0.4, and the D component with a coefficient of 0.7. From each 100 mg of αP, 68 mg of C and 22 mg of D were isolated. 3 mg of a minor fraction with Kd 0.1, containing A and B components as well as C, were also obtained. D but not C reacts with rabbit antiserum to human αLP. C and D differ substantially in content of arginine, histidine, ½-cystine, isoleucine, and tryptophan.

Authors

Daniel Rudman, Luis A. Garcia, Carolyn H. Howard

The integrity of the ether linkage during thyroxine metabolism in man

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Abstract

The structures of thyroxine metabolites after total deiodination bear on the mode of thyroxine (T4) action in vivo. The present study was undertaken to determine the integrity of the ether linkage during thyroxine metabolism in man. Normal volunteers were given simultaneous intravenous injections of two thyroxines labeled with either 14C or 3H on the opposite sides of the ether linkage, D,L-[α,β-3H]T4 and D,L-[phenolic ring-14C]T4. The ratio of alanine side chain to phenolic ring which was measured as 3H:14C ratio was found to remain constant in the serum, urine, and feces during the subsequent 3 wk. The disappearance rates of the 3H and 14C radioactivity from blood were similar. The values of half-life were in the ranges of 4.2-6.7 days. 51-63% of the 3H and 50-57% of the 14C doses were recovered from urine and 13-20% of the 3H and 15-20% of the 14C doses were recovered from feces. Chromatography of the urinary metabolites confirmed that the phenolic ring and the nonphenolic ring including at least part of the side chain remained linked together.

Authors

Constance S. Pittman, Virginia H. Read, Joseph B. Chambers Jr., Haruyoshi Nakafuji

The measure in vivo of regional cerebral oxygen utilization by means of oxyhemoglobin labeled with radioactive oxygen-15

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Abstract

Regional cerebral oxygen utilization rate is measured in vivo by the following method:

Authors

Michel M. Ter-Pogossian, John O. Eichling, David O. Davis, Michael J. Welch

Biosynthesis of cytidine diphosphate diglyceride by human platelets

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Abstract

Homogenates of human platelets contain an enzyme which catalyzes the formation of cytidine diphosphate diglyceride from cytidine triphosphate and phosphatidic acid. The enzymatic activity could not be dissociated from platelet particles and the greatest specific activity was found in the membrane fraction. The Km for cytidine triphosphate was 0.16 mmole/liter and the apparent Km for phosphatidic acid was 6.2 mmoles/liter. The pH optimum was 7.0 and the most effective buffers were triethanolamine-HCl and Tris-HCl. The reaction was dependent on the presence of divalent cations, magnesium being the most effective of those investigated. Monovalent cations did not alter the reaction rate. Evidence is presented that the cytidine diphosphate diglyceride produced can serve as a precursor for the synthesis of phosphatidylinositol. No difference was found in the enzymatic activity in platelets from normal subjects and from patients with diseases known to interfere with platelet thromboplastic function.

Authors

Frank L. Call II, William J. Williams

The effects of deoxygenation of adult and fetal hemoglobin on the synthesis of red cell 2,3-diphosphoglycerate and its in vivo consequences

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Abstract

Patients over 1 month of age with arterial oxygen pressures of less than 60 mm Hg were found to have elevated red cell 2,3-diphosphoglycerate (2,3-DPG) levels and blood with a decreased affinity for oxygen. The increase in 2,3-DPG was proportional to the degree of hypoxemia. In patients under 1 month of age this relationship was not observed. Red cells from adults, but not newborns, showed rapid increases in 2,3-DPG when incubated under nitrogen. Adult, but not fetal, deoxyhemoglobin was shown to facilitate in vitro synthesis of 2,3-DPG by binding this organic phosphate and relieving the product inhibition of 2,3-DPG mutase.

Authors

Frank A. Oski, Arlan J. Gottlieb, William W. Miller, Maria Delivoria-Papadopoulos

Diffusing capacities and ventilation: perfusion ratios in patients with the clinical syndrome of alveolar capillary block

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Abstract

Studies were performed on 10 patients with the clinical syndrome of alveolar capillary block while each patient was breathing four different inspired oxygen mixtures. The data were interpreted using the principle of the Bohr integral isopleth with which alveolar oxygen tension in the differently ventilated parts of the lung can initially be treated as unknown. It is then possible to determine the distribution of ventilation, of perfusion, of diffusing capacity, of lung volume, and of alveolar and end capillary blood oxygen tension in the variously functioning parts of the lung. In two patients shunts were the major factor interfering with oxygen transfer. In four others inequalities in ventilation: perfusion ratios and in diffusing capacity in different parts of the lung were the factors interfering with oxygen transfer. In four more patients ventilation: perfusion ratios were the same throughout the lung, the only disturbance of oxygen transfer being in the total diffusing capacity or in its distribution between the different parts of the lung.

Authors

Hartmut Arndt, Thomas K. C. King, William A. Briscoe