Red Cell pH Research Articles

Hemoglobin-oxygen affinity in anemia.

In blood of 21 anemic patients and 8 normal subjects (N) three oxygen dissociation curves each were measured at different pH values to calculate Bohr coefficients after acidification with CO2 (BCCO2) or fixed acid (BCFA), and other important parameters of oxygen affinity. The patients had either low hemoglobin or red cell production (L: n = 11, 7.3 g/dl Hb) or high erythrocyte production combined with high loss (H: n = 10, 7.8 g/dl Hb). The standard half saturation pressure P50 (pH 7.4, 37 degrees C) was equally elevated in both anemic groups (L: 30.5, H: 30.8, N: 26.7 mmHg), as well as the diphosphoglycerate concentration (DPG) (L: 18.7, H: 18.6, N: 12.7 mumol/g Hb). The red cell pH of the anemics was lower than for the N (approximately 0.045 units) causing part of the difference in P50. Hill's "n" tended to high values in the anemics except at low O2-saturation in the H. For BCCO2 no significant difference among the groups was observed. BCFA, however, increased in the H at low SO2 compared to the N and L. The cause for most of the changes in hemoglobin oxygen affinity in anemics was the high [DPG]. The combination of high P50 and high "n" value as in the L seems to be most advantageous for tissue oxygenation.

Hypercapnic acidosis in the rainbow trout (Salmo gairdneri). I. Branchial ionic fluxes and blood acid–base status

Branchial solute fluxes as well as blood respiratory, ionic, and acid–base variables were monitored before, during, and after 72 h of exposure to external hypercapnia (1% CO2; [Formula: see text]). Hypercapnia induced an immediate extracellular respiratory acidosis that was gradually regulated over the 72-h period by an elevation of the plasma bicarbonate [Formula: see text] level. Red blood cell pH changed in a manner similar to whole blood pH but the reduction of red blood cell pH during hypercapnia was significantly less than that predicted from in vitro experiments. We argue that elevated plasma levels of epinephrine in the first 12 h of hypercapnia may serve to stabilize red blood cell pH during the severe reduction of whole blood pH, thereby preventing excessive depressions of arterial oxygen content. Elevated external CO2 tension caused changes in the branchial net flux (JnetCl−) such that the arithmetic difference between sodium net flux (JnetNa+) and JnetCl− (JnetNa+ – JnetCl−) increased during hypercapnia and then decreased post-hypercapnia. These results are consistent with enhanced branchial acid excretion and are discussed with reference to the involvement of the gill in the regulation of hypercapnic acidosis.

Effects of adrenaline on ionic equilibria in red blood cells of rainbow trout (Salmo gairdneri)

Effects of adrenaline on the equilibrium distributions of Na(+) , K(+) , H(+) , Cl(-) , and H2O across the cell membrane of rainbow trout (Salmo gairdneri) erythrocytes were determinedin vitro, as a function of P CO2 (1.76-7.77 torr). CO2-carrying capacity of the blood was also examined. Plasma catecholamine concentrations inunanaesthetized, unrestrained trout were 3.1 nM adrenaline and 1.2 nM noradrenaline. Elevation of the plasma adrenaline concentrationin vitro to 4.6 × 10(3) nM resulted in net gains of Na(+) , Cl(-) and H2O by red cells, a net loss of H(+) from red cells, and a pronounced red cell swelling. Adrenaline also reduced the CO2-carrying capacity of trout bloodin vitro. The magnitudes of these effects increased with PCO2 and, thus, were sensitive to blood HCO3 (-) concentrations. The distribution of K(+) between red cells and plasma was unaffected by adrenaline. Adrenergic-mediated ion movements and red cell swelling were sensitive to both propranolol and SITS. These results are consistent with the symport NaCl uptake model for adrenergic-mediated swelling of Baroinet al. (1984). The adrenergic response of fish erythrocytes may function to ameliorate the effects of blood acidoses on O2-carrying capacity by maintaining red cell pH in the face of a decrease in plasma pH.

Physiological consequences of prolonged aerial exposure in the American eel,Anguilla rostrata: blood respiratory and acid-base status

The physiological consequences of prolonged air-exposure on blood respiratory and acid-base properties were examined in the American eel (Anguilla rostrata). Eels displayed a low capacity for aerial gas transfer as indicated by pronounced increases and decreases in arterial CO2 and O2 tensions, respectively. The increase in arterial CO2 tension contributed to severe extracellular acidosis. The decrease in arterial O2 tension, combined with a marked reduction in red blood cell pH and concomitant Bohr and Root effects, caused arterial O2 content to decline to levels that were insufficient to support metabolic requirements, aerobically. Consequently, the rate of anaerobic glycolysis increased during air-exposure as suggested by a gradual elevation of blood lactate levels after 12 h. Increased anaerobic glycolysis and associated ATP hydrolysis and/or degradation of internal ATP stores further depressed blood pH as metabolic acid, produced by these processes, entered the circulation. Unlike other fishes previously examined, red blood cell pH was not regulated preferentially during the extracellular acidosis but simply conformed to the in vitro relationship between red blood cell and whole blood pH. Although capable of surviving prolonged air-exposure, the results demonstrate nevertheless and perhaps not surprisingly that eels, unlike true amphibious fishes that utilize gills or buccal epithelia for gas transfer, are not particularly well-adapted for gas exchange in air but do display an unusual tolerance to hypoxemia.

Internal Hypoxia-Hypercapnia in Tench Exposed to Aluminium in Acid Water: Effects on Blood Gas Transport, Acid-Base Status and Electrolyte Composition in Arterial Blood

ABSTRACT Tench exposed for 6 days to acid (pH 5) hard water ([Caz+] = 3·5 mmol I−1) in the presence of aluminium (2 mg I−1) showed a rapid decrease (within 3 h) in dorsal aortic and a simultaneous rise in -Arterial oxygen content and haemoglobin oxygen (Hb-O2) saturation decreased sharply, as did red cell [Hb], whereas blood haematocrit (Het) and [Hb] increased. Red cell nucleoside triphosphate (NTP) content was reduced within 1 day through a selective reduction in guanosine triphosphate (GTP). Although the rising caused an extracellular acidosis (to which lactic acid production and perhaps H+ influx at the gills contributed), red cell pH increased compared to control values, mainly as a result of the decrease in Hb-O2 saturation. Plasma [Cl−] declined, whereas [HCO3−], [K+] and [Ca2+] increased. Ionic disturbances, however, were small compared to the changes in blood O2 transport, which appeared to correlate with high ambient [Ca2+], Tench exhibited a high tolerance to the acid-Al exposure and most of the above parameters showed partial recovery within 1–2 days. In some specimens, however, the exposure was lethal because of an obstruction of gill function, and arterial blood became almost completely deoxygenated and showed very low pH values and high lactate concentrations, attesting to deep internal hypoxia.

Influences of exercise-stress and adrenaline upon intra- and extracellular acid-base status, electrolyte composition and respiratory properties of blood in tench (Tinca tinca) at different seasons.

Exercise-stress in tench resulted in severe acidosis in both the red cells and the extracellular fluid in vivo. These coincident pH decreases conformed to the in vitro pHi-pHe relationship for tench blood in the oxygenated state. The extracellular acidosis was primarily respiratory in winter and metabolic in spring and summer. This was due to more effective buffering of metabolic protons in winter by an elevation in [HCO3-] levels, rather than to differences in the lactic- and carbonic acid loads. A good correspondence was found between buffered metabolic protons and increases in [lactate]. There was no evidence for beta-adrenergic red cell swelling and associated red cell pH changes in tench both after exercise and adrenaline infusion. Arterial O2 transport was, however, improved in exercise by pronounced increases in PO2. This increase was not of adrenergic origin, as adrenaline alone caused a decrease in arterial PO2. Large increases in plasma potassium concentration and small elevations of chloride and calcium levels occurred in exercise. Hematocrit and blood [Hb] also increased, probably due to an adrenergic release of erythrocytes from the spleen, but these increases were small and appeared unimportant for blood O2 transport. Seasonal differences were found in exercise-induced changes in [lactate], in the magnitude of electrolyte and PO2 changes, as well as in resting values for pHe, pHi, [HCO3-], [Cl-] and [Ca++]. The origin and importance of these are discussed.

Ionic equilibria in red blood cells of rainbow trout ( Salmo gairdneri): Cl −, HCO 3− and H +

The equilibrium distributions of H +, Cl − between plasma and erythrocytes of rainbow trout ( Salmo gairdneri) blood were determined as a function of plasma pH (pHe, 7.0–8.2), temperature (5–15°C), and mode of blood acidification (CO 2, HCl, lactic acid). The relationship between red cell pH (pHi) and pHE was not affected significantly by temperature or mode of blood acidification. H +, Cl − and HCO 3 − were passively distributed across the red cell membrane as evidenced by the membrane's high permeability to Cl − and the similar Donnan ratios for H + and Cl − at any given pHe. The relationship between pHe and the Donnan ratio for bound CO 2 had a similar slope to the relationships between pHe and the Donnan H + and Cl − ratios but was shifted upwards, presumably due to formation of carbamino compounds inside the rd blood cell. This carbamino formation was enhanced at lower temperatures when blood pH was elevated.

The promotion of catecholamine release in rainbow trout, Salmo gairdneri, by acute acidosis: interactions between red cell pH and haemoglobin oxygen-carrying capacity.

A fall in blood pH was generated either by infusion of HCl or by reducing gill ventilation and raising blood PCO2 in rainbow trout, Salmo gairdneri Richardson. The acute acidosis resulting from HCl infusion caused an increase in plasma adrenaline and noradrenaline concentrations, the adrenaline increase being proportional to the decrease in blood pH. Fish subjected to a prolonged respiratory acidosis, caused by a reduction in gill ventilation, showed no increase in catecholamines 24 h after the change in gill ventilation. We suggest that catecholamine levels increase in response to a pH decrease, but if acidotic conditions are maintained, circulating catecholamines return to low levels. There was a much smaller decrease in erythrocytic pH with a fall in plasma pH when catecholamine levels were high. This ameliorating effect of catecholamines on erythrocytic pH during a plasma acidosis maintains the oxygen-carrying capacity of the haemoglobin. If erythrocytic pH was decreased by increasing blood PCO2 in vitro, then there was a fall in haemoglobin oxygen-carrying capacity which was proportional to the reduction in pH. We conclude that catecholamines are released into the blood in proportion to the fall in blood pH but if the pH is maintained the circulating catecholamines return to their initial low levels. The elevated catecholamine concentrations in blood safeguard against any impairment of haemoglobin oxygen-carrying capacity by maintaining erythrocytic pH in the face of a plasma acidosis.

Mechanisms of pH regulation in lamprey (Lampetra fluviatilis) red blood cells.

Mechanisms regulating the red cell pH in lamprey (Lampetra fluviatilis) were studied using the ammonium chloride prepulse technique. The cells were initially incubated in a physiological saline containing 20 mmol l-1 ammonium chloride, and intracellular pH measured with the DMO technique. Ammonium chloride was then rapidly removed by centrifugation, and the changes in the intracellular pH followed. The intraerythrocytic pH is primarily regulated by an amiloride-sensitive sodium/proton exchange. When sodium is present in the incubation medium, the intracellular pH rapidly recovers from the acidification associated with the removal of ammonium chloride from the incubation. When sodium is removed from the incubation medium, intracellular pH does not recover, and when the cells are treated with 10(-3) mol l-1 amiloride in the presence of sodium, carbon dioxide and bicarbonate, the intracellular pH recovery is drastically reduced. The movements of carbon dioxide, its consecutive catalysed hydration and dissociation to protons and bicarbonate and, possibly, movements of bicarbonate out of the cell acidify the cell contents. This is shown by the observation that the steady-state intracellular pH is higher in a HEPES-buffered medium than in a CO2/HCO3(-)-buffered medium at the same extracellular pH. The acidification is dependent on cellular carbonic anhydrase activity, present in lamprey red cells, which speeds up the hydration reaction. When the action of carbonic anhydrase is inhibited by acetazolamide, removal of ammonium chloride from the incubation medium does not cause intracellular acidification.

Pronounced influence of Hb-O2 saturation on red cell pH in tench blood in vivo and in vitro.

At an extracellular pH of 7.9 the red cell pH in tench blood exhibits a nonlinear, strongly inverse relationship with Hb-O2 saturation, both when investigated in vitro and in vivo (in fish exposed to acid water with and without aluminium). The pHi difference between deoxygenated and oxygenated erythrocytes is large (i.e., 0.35 pH units), which can be accounted for by the Haldane effect and the buffering properties of the blood. The major shift in pHi occurs between 50 and 100% Hb-O2 saturation, indicating an almost full exploitation of the Haldane effect within the normal physiological range of blood O2 saturations.

Red cell pH of lamprey (Lampetra fluviatilis) is actively regulated

The red cell pH of lamprey (Lampetra fluviatilis) was measured using the DMO method (based on the passive distribution of the wead acid, DMO, across the red cell membrane). The measured red cell pH was higher than the pH of the incubation medium throughout the pH range (7.2–8.2) studied, and higher than the red cell pH calculated from the chloride distribution ratio. Treatment of cells with the metabolic inhibitors 2,4-dinitrophenol or KCN caused a drop in the red cell pH to values lower than the pH of incubation medium, and abolished the difference between the measured red cell pH and the pH calculated from the chloride distribution ratio. These data strongly suggest that the proton gradient across lamprey red cell membrane is actively maintained. Acid extrusion from lamprey red cells may require sodium, as indicated by the observation that when choline was substituted for sodium in the incubation medium, the intracellular pH decreased significantly.

Blood oxygen transport and acid-base status of stressed trout ( Salmo gairdnerii): Pre- and postbranchial values in winter fish

1. 1. Rainbow trout, obtained from a temperature below 5°C and kept at 13–14°C for 2 weeks, were cannulated via both dorsal and ventral aorta, and chased for 5 min at 14°C. 2. 2. The stress caused a marked extracellular acidosis which had both respiratory and metabolic components. 3. 3. The dorsal aortic red cell pH also decreased, from 7.33 to 7.12, as a result of the stress. 4. 4. This caused a drop in the arterial oxygen saturation, although arterial oxygen tension remained unchanged. 5. 5. Additionally, no red cell swelling was observed. Also, the carbon dioxide and red cell chloride data suggest that bicarbonate influx into the red cells and, consequently, carbon dioxide excretion increased in stress. 6. 6. These findings strongly suggest that the red cells of the winter fish used lacked beta-adrenergic responses. 7. 7. In the apparent absence of beta-adrenergic responses, the ventral aortic red cell pH was maintained at a nearly constant level, probably by the Haldane proton uptake upon deoxygenation of the blood in the tissues. 8. 8. Consequently, and since the ventral aortic oxygen tension remained unchanged, the oxygen saturation of venous blood was not affected by stress.

The influence of L-sorbose on red cell flow properties, shape and packing ability.

Since the sweet ketohexose L-sorbose causes overt hemolysis in dogs but not in man, we examined the possibility that L-sorbose induces a "prehemolytic state" of human red cells, manifesting itself as impairment of rheological red cell properties. After 2 hours incubation at 37 degrees C relative viscosity of red cell suspensions measured by radial spreading in filter paper and packing ability of red cells were normal. Incubation for 24 and 48 hours of red cells in media containing L-sorbose, glucose or no sugar showed that relative viscosity was best maintained in glucose. Relative viscosity and packing ability of red cells in L-sorbose containing suspensions decreased less than in suspensions without sugar. This difference was independent of the glucose metabolism, red cell ATP, osmolality and pH of the suspending media, but appeared to be related to different degrees of spheroechinocytic red cell shape transformation observed in different suspending media. It is possible that L-sorbose has some antiechinocytic properties and/or that it induces an alteration of red cell membrane flexibility. There is no indication of an L-sorbose induced "prehemolytic state" in human red cells.

Alterations in oxygen transport following WR-2721

The toxicity of radiation and alkylating agent chemotherapy is in part related to free radical formation in DNA and associated proteins, which is enhanced by oxygen and other electron affinic compounds. During the Phase I clinical trials of WR-2721 and alkylating agent chemotherapy, venous blood samples were obtained prior to and immediately following the WR-2721 infusion. We have observed a marked increase in the oxygen saturation of venous blood following WR-2721 (430–910 mg/m 2 at a rate of 15 mg/m 2/minute). The mean venous P0 2 (P v,0 2) rose from a baseline of 34.0 ± 13.54 torr to a mean value of 54.60 ± 12.47 torr ( p < 0.001). The percent venous oxygen saturation increased from 54.52 ± 21.38% to 82.73 ± 7.66%. The highest values generally occurred within the first 2 hours after the completion of the WR-2721 infusion. No significant differences were found between the pre and post WR-2721 values for either the venous pH, C0 2, or bicarbonate levels. Despite increased P v,0 2, the patients' heart rates, blood pressures, or respiratory rates did not change pre and post WR-2721. No apparent differences were noted in the effects of WR-2721 or P v,0 2 when given at doses of 740 or 910 mg/m 2. However, when WR-2721 (418–1100 mg/m 2) was administered over 15 minutes, the P v,0 2 increased in only 8 13 courses. We postulated that the marked increase in venous blood oxygen concentration was secondary to one of the following mechanisms: 1) Increased affinity of hemoglobin for oxygen, 2) microcirculatory shunting, or 3) decreased tissue requirements for oxygen. In 12 patients oxygen-hemoglobin dissociation curves and intracellular red cell pH's were obtained before and after 740–910 mg/m 2 of WR-2721. Despite the significant increase in oxygenation of venous blood after WR-2721, there were no changes in either oxygen-hemoglobin dissociation or intracellular red cell pH to account for this increase. The oxygen consumption of peripheral blood granulocytes was measured prior to and following 15 courses of W R-2721. A marked decrease in granulocyte oxygen consumption was observed in 6 8 patients who had a significant increase in P v,0 2 and only 1 7 patients who had either a decrease or no change in P,02 after WR-2721. Our preliminary investigations suggest that the increased venous blood oxygen content may be secondary to a reduction in normal tissue oxygen consumption. WR-2721 may afford protection by both decreasing oxygen consumption and delivery to normal tissues and increasing intracellular sulfhydryis.

CO2 and H+ Excretion By Swimming Coho Salmon, Oncorhynchus Kisutch

ABSTRACT Coho salmon, Oncorhynchus kisutch (Walbaum), were swum at constant speed in a ‘Brett-type’ tunnel respirometer. Blood , and pH as well as total CO2 content and red blood cell pH were unchanged during swim ming. The RE (respiratory exchange ratio) was slightly less than 0·7 when the fish was swimming in normal sea water, indicating that some CO2 is retained by the fish. Lowering seawater bicarbonate concentration increased HCO3− transfer, presumably because of passive bicarbonate loss. A reduc tion in seawater pH from 7 ·95 to 7 ·1 sharply reduced both CO2 and hydrogen ion transfer, resulting in very low RE values of about 0 ·2. Hydrogen ion excretion was elevated during prolonged swimming following high speed swimming activity. It would appear that CO2 and hydrogen ion transfer by fish need not be matched and changing internal and external conditions can have a marked and separate effect on hydrogen ion and CO2 excretion and therefore on the RE value.

Intraoperative autotransfusion during abdominal aortic reconstruction

Intraoperative autotransfusion by a continuous-flow centrifuge system was used during more than 300 abdominal aortic reconstructions at the Cleveland Clinic since May 1979. Fifty consecutive patients undergoing such operations were studied prospectively. Volumes of blood lost, salvaged, and transfused during each operation were tabulated. Autologous autotransfused blood was compared with homologous bank blood with respect to oxygen-carrying capacity, coagulation factors, microaggregate levels, red cell mass, pH, and free hemoglobin concentration. Chromium-51 red cell survival studies were performed in autotransfused blood in random patients and in control subjects. Renal, hepatic, and coagulation functions were determined during the first postoperative week. Each patient received a mean volume of 1,203 ml of autotransfused blood and 1,682 ml of bank blood to replace a mean operative blood loss of 2,386 ml. Red blood cell survival of both salvaged autologous and unshed autologous blood in the control group was nearly identical. Salvaged blood had superior oxygen-carrying capacity, a lower microaggregate level, and better buffering capacity than bank blood. Although transient elevations in liver function values and free hemoglobin levels were noted, no clinically important aberration of coagulation, hepatic, or renal function was demonstrated.

Physiological changes in trout ( Salmo gairdneri) during a short-term exposure to resin acids and during recovery

Six rainbow trouts were exposed to a 2 mg/1 concentration of resin acids for 24 h. The toxicants influenced respiration by causing a decrease in arterial Po 2, red cell volume and pH, and an increase in ATP/Hb ratio. These responses were reversible on recovery. A disturbance in hydromineral balance was shown by a decrease in plasma chloride concentration, which was reversible in all but one fish. This fish had additional metabolic difficulties as shown by increases in plasma lactate concentration and enzyme activity. An indication of liver dysfunction was the increase in plasma bilirubin concentration, continuing throughout recovery.

The Effect of Hemodialysis on Oxygen Transport in Chronic Uremics

Previous studies from our laboratory suggested a decrease in tissue oxygen delivered during hemodialysis of chronic uremic patients due to an increase in hemoglobin-oxygen affinity, i.e. decrease in P50. This current study was designed to determine whether the changes in cardiac index and/or tissue oxygen extraction could compensate for increases in hemoglobin-oxygen affinity previously observed, so that total tissue oxygen delivery was unchanged during hemodialysis. This study demonstrated in patients during a 6-hour hemodialysis that: 1) no change occurs in hemoglobin-oxygen affinity expressed as P50, with unchanging plasma inorganic phosphate and red blood cell pH; 2) increased extraction of oxygen from tissue, measured via (A-V) O2 difference compensates for decreased oxygen delivery due to decreased cardiac output; and although there was no demonstrable change in hemoglobin-oxygen affinity, it would appear that increased tissue extraction of oxygen via other mechanisms should be easily able to compensate for previously reported changes in P50.

Exchanges between plasma and red cells at a variable temperature

When blood temperature is varied in closed (‘anaerobic’) conditions, the difference between plasma pH and red cell pH stays remarkably constant. Model studies show that this constancy results from diffusive CO 2 equilibrium and Donnan equilibrium of CHO 3 − and Cl − ions, more than from a strictly defined buffer composition.

Pathogenesis of respiratory failure (ARDS) after hemorrhage and trauma: I. Cardiorespiratory patterns preceding the development of ARDS.

To evaluate clinical and physiologic determinants of adult respiratory distress syndrome (ARDS), we studied 152 consecutively monitored patients with trauma and hemorrhage: 60 developed ARDS. The cardiorespiratory patterns of hemorrhage and trauma patients who did not develop ARDS were compared to those who subsequently did develop ARDS, but before the time of their ARDS. Comparisons also were made in the patients with trauma and those with hemorrhage, as well as in those who survived and those who did not. Hemorrhage and trauma patients who developed ARDS had greater reductions in blood volume, red cell mass, PaCO2 and O2 delivery throughout all stages, as well as greater pulmonary vascular resistance index (PVRI) and pH in the early and middle stages. Nonsurvivors of ARDS had greater deficits in blood volume and red cell mass, higher PVRI and pH, as well as lower central venous pressure (CVP), hemoglobin (Hgb), and PaCO2 than did ARDS survivors. Hemorrhage patients had lower blood volume, left ventricular function, O2 delivery and VO2, as well as higher systemic vascular resistance index (SVRI), PVRI, and O2 extraction than either the trauma patients or normal subjects. Description of the temporal cardiorespiratory patterns before the clinical appearance of ARDS showed the progressive appearance of these deficits beginning 36 h before the hypoxemia was observed. The data are consistent with the concept that ARDS after hemorrhage and trauma is preceded by hypovolemia, reduced myocardial performance, inadequate O2 delivery, and inadequate O2 extraction needed to maintain VO2 at the elevated levels demanded by the increased metabolic requirements of the injured patients. Thus, the so-called shock lung is a complication of shock associated with hypovolemia, hypoxemia, and inadequate cardiac compensatory responses to increasesd O2 demands.