Biomedical subjects

A Frans

Publications and source records attributed to A Frans.

At least 19 recordsLinked to original sources

PubMed2005

Effects of intravenous infusions of sodium bicarbonate on blood oxygen binding in calves with diarrhoea.

Twelve diarrhoeic calves were treated intravenously with an isotonic solution containing sodium bicarbonate, and their oxygen equilibrium curves (OECS) were calculated under standard conditions and compared with those of a group of healthy calves. The relationships between the OECS for arterial and venous blood and the oxygen extraction ratio were investigated. In the diarrhoeic calves, the affinity of haemoglobin for oxygen, measured under standard conditions, was increased compared with the healthy animals. During the infusion, the standard partial oxygen pressure at 50 per cent saturation of haemoglobin (P50) values stayed below the values recorded in the healthy animals. At the end of the infusion the mean standard P50 of the diarrhoeic calves was lower than before the infusion. The combined effects of all the regulating factors on blood oxygen binding resulted in the OECS of the arterial and jugular venous blood of the diarrhoeic calves remaining unchanged compared with the healthy calves. However, the administration of the infusion decreased the P50 of both the arterial and venous blood to below the value recorded in the healthy calves. Oxygen extraction by the tissues was impaired in the diarrhoeic calves throughout the infusion, and they remained dehydrated and depressed until 120 minutes after the infusion began.

Animals↗

PubMed2005

Blood-oxygen binding in healthy Standardbred horses.

The purpose of this study was to determine the effect of regulating factors on the oxygen equilibrium curve (OEC) under standard conditions and then to calculate the oxygen extraction between arterial and jugular venous blood in healthy Standardbred horses. The results were compared to those previously obtained in humans and cattle, using the same experimental method. The partial oxygen pressure at 50% saturation of haemoglobin, measured under standard conditions (standard P50), was 24.8+/-2.0 (SD of mean) mmHg. This value was similar to the cattle standard P50 (25.0+/-1.4 mmHg, SD of mean) but lower than the human standard P50 (26.6+/-1.2 mmHg, SD of mean) previously reported using the same experimental method. The effects of regulating factors on the standard OEC were also determined, and a major effect of pH and temperature was noted. In contrast, partial carbon dioxide pressure played only a minor role in horses, compared to cattle and humans. No significant correlation was found between phosphate and chloride concentrations and standard P50.

Animals↗

PubMed2004

Haemoglobin oxygen affinity and regulating factors of the blood oxygen transport in canine and feline blood.

Complete dynamic oxygen equilibrium curves (OEC) on dogs and cats whole blood were measured at 33, 37 and 41 degrees C. OEC were also run at three partial carbon dioxide pressures (20, 40 and 80 mmHg) as well as at five pH levels (7.2, 7.3, 7.4, 7.5 and 7.6). 2,3- diphosphoglycerate (DPG) concentrations were determined. Results were compared to those previously published in humans, using the same experimental method [Comp. Biochem. Physiol. 106 (1993) 687]. In standard conditions (pH 7.4, pCO2 40 mmHg and temperature 37 degrees C), the partial oxygen pressure at half-saturation of haemoglobin (p50) was 30.0+/-1.3 mmHg for dogs and 34.1+/-1.8 mmHg for cats. Cat's OEC was thus rightshifted compared to dog's OEC, itself rightshifted compared to human OEC. 2,3-DPG concentrations were higher in dogs than in men until they were very low in cats. Contrary to that observed in human medicine, no significant correlation was identified between standard p50 and canine 2,3-DPG values. Influence of pH, pCO2 and temperature on the OEC was saturation dependent. In dogs, Delta log p50/Delta pH was equal to -0.370, Delta log p50/Delta log pCO2 was 0.093 and Delta log p50/Delta T was 0.020. In cats, Delta log p50/Delta pH was equal to -0.405, Delta log p50/Delta log pCO2 was 0.080 and Delta log p50/Delta T was 0.016. Practically, temperature and pH variations exert a lesser influence in domestic carnivores than in humans, effect of pCO2 being similar in both.

2,3-Diphosphoglycerate↗

PubMed2003

Calculation of bovine haemoglobin oxygen saturation by algorithms integrating age, haemoglobin content, blood pH, partial pressures of oxygen and carbon dioxide in the blood, and temperature.

In human and veterinary medicine, arterial and venous haemoglobin oxygen saturations are often used to estimate the severity of a disease and to guide therapeutic decisions. In veterinary medicine, haemoglobin oxygen saturation (SO(2)) is usually calculated using a blood gas analyser and algorithms developed for humans. It is possible, therefore, that the values obtained in animals may be distorted, particularly in animals with a high haemoglobin oxygen affinity, like young calves. In order to verify this hypothesis, we compared the arterial (SaO(2)) and venous (SvO(2)) haemoglobin oxygen saturations calculated using three different algorithms, and the oxygen exchange fraction (OEF) at the tissue level, which is the degree of haemoglobin desaturation between arterial and venous blood (SaO(2)-SvO(2)), with the values obtained from the whole bovine oxygen equilibrium curve (OEC) determined by a reference method. The blood gas analysers underestimated SvO(2) values; consequently, the OEF was overestimated (by about 10%). Two methods of reducing these errors were assessed. As the haemoglobin oxygen affinity decreases during the first month of life in calves a relationship between PO(2) at 50% haemoglobin saturation (P50) and age was established in order to correct the calculated values of venous and arterial SO(2), taking into account the estimated position of the OEC. This method markedly reduced the error for SvO(2) and OEF. Secondly, the SO(2) was calculated using a mathematical model taking into account the age of the animal and the specific effects of pH, PCO(2), and temperature on the bovine OEC. Using this method, the mean difference between the OEF values calculated using the mathematical model and those calculated by the reference method was close to zero. The errors produced by blood gas analysers can thus be minimised in two ways: firstly, by simply introducing a P50 estimated from the age of the calf into the analyser before the measurement; and secondly, by calculating the SO(2) using a mathematical model applied to the bovine OEC.

Algorithms↗

PubMed2001

Blood oxygen binding in calves with naturally occurring diarrhea.

OBJECTIVE: To assess blood oxygen binding in calves with diarrhea. ANIMALS: 22 dairy and 26 double-muscled calves with diarrhea, 31 healthy dairy calves and 37 healthy double-muscled calves. PROCEDURE: Severity of disease, including the ability of affected calves to stand, was evaluated. Hydration and signs of depression were scored. Venous and arterial blood samples were collected, and 2,3-diphosphoglycerate, ATP, chloride, inorganic phosphate, lactate, pyruvate, total protein, albumin, and hemoglobin concentrations, and Hct, pH, Pco2, and PO2 were determined. Oxygen equilibrium curves (OEC) were constructed under standard conditions, and oxygen extraction ratios were calculated. RESULTS: Recumbent calves of both breed-types were more dehydrated and had more severe signs of depression than ambulatory affected calves. In both breed-types, hemoglobin oxygen affinity was increased in calves with diarrhea, compared with healthy calves, as indicated by a decrease in standard partial oxygen pressure (P50). Diarrhea induced hypocapnia and hypothermia in the most severely affected calves, which counteracted the acidosis-induced right shift in arterial and venous OEC. Arterial and venous P50 were significantly less in double-muscled calves with diarrhea than healthy calves, whereas P50 for affected dairy calves were similar to those of healthy calves. Except in the most severely affected dairy calves, oxygen extraction ratio was significantly less in calves with diarrhea, compared with healthy calves. CONCLUSIONS AND CLINICAL RELEVANCE: Release of oxygen from blood may be impaired in calves with diarrhea, depending on the effect of the disease on certain blood biochemical variables.

2,3-Diphosphoglycerate↗

PubMed2001

[Respiratory rehabilitation in patients with bronchial asthma and chronic obstructive pulmonary disease (COPD) in Kinshasa].

A number of studies in western countries have shown that respiratory and physical rehabilitation of patients with chronic obstructive pulmonary disease (COPD) only has a minimal effect on respiratory function but can significantly improve physical capacity. The aim of our study was to apply these methods to patients in Kinshasa, Democratic Republic of Congo. We treated 38 patients (20 women) who had bronchial asthma (n=14) or COPD (n=24). These ambulatory patients were treated in two different hospitals in Kinshasa, the university hospital and the general hospital, three times per week for twelve weeks. The patients were treated with kinestherapy and inhaled bronchodilator drugs (salbutamol, and/or ipratropium bromide with a boreal nebulizer) as well as bronchial hygiene and performed breathing exercises on a Bodyguard Ergometer 990 with walking, running and climbing steps until exhaustion. After the rehabilitation program FEV1 increased from 1.37 +/- 0.62 (50% expected) to 1.54 +/- 0.69 (56% expected) (p<0.01). The same trend was observed for walking distance (from 644 +/- 459 m to 1213 +/- 569 m, p<0.001) and for maximal power developed on the cycloergometer (from 45 +/- 20 w to 73 +/- 37 w, p<0.001). In contrast, the maximal work load performed during climbing steps (from 106 +/- 44 w to 115 +/- 23 w) did not improve significantly. COPD patients improved their FEV1 significantly compared with asthma patients. Our study show that pulmonary rehabilitaion increase the level of spontaneous physical activity. The pulmonary rehabilitation program changes the quality of life of COPD patients who are able to move about better for longer periods of time, have a longer walking distance, and improved physical activity level.

Activities of Daily Living↗

PubMed2000

Lung function study and diffusion capacity in anorexia nervosa.

STUDY OBJECTIVES: In humans, malnutrition alters the respiratory system in different ways. It impairs the ventilatory drive, decreases respiratory muscle strength and reduces immune competence. In addition, typical emphysema-like changes were demonstrated in starved animals. The presence of emphysema has never been demonstrated in starved humans. Our objective was to investigate whether pulmonary emphysema occurs in anorexia nervosa by means of a pulmonary function study. POPULATION AND METHOD: We examined 24 women aged between 14 and 38 years (nine smokers). We studied the lung function including lung volumes, ventilatory capacity, maximal respiratory pressures and transfer factor, as well as PaO2. RESULTS: All respiratory tests were within normal limits with the exception of decreased maximal inspiratory (59% of predicted values) and expiratory pressures (35%), and increased residual volume (162%). Diffusion capacity (98.1 +/- 16.2%) and transfer coefficient (98.4 +/- 16.2%) were also normal. The diffusion coefficient was lower in current smokers than in those who had never smoked (P < 0.01), a difference similar to that calculated from existing reference values for transfer factor for smokers and nonsmokers. CONCLUSION: In anorexia nervosa, pulmonary function tests are within normal limits with the exception of maximal pressures and residual volume. Diffusion capacity is not decreased. The present results within the limitations of the used method are not compatible with the hypothesis of starvation-induced pulmonary emphysema.

Adolescent↗

PubMed2000

Blood oxygen binding in double-muscled calves and dairy calves with conventional muscle conformation.

OBJECTIVE: To assess in vivo blood oxygen binding in double-muscled calves and dairy calves with conventional muscle conformation. ANIMALS: 58 dairy and 48 double-muscled calves. PROCEDURE: Calves were classified as neonatal (24 hours old) or older calves (2 to 26 days old). Venous and arterial blood samples were collected, and hemoglobin concentration, pH, PCO2, and PO2 were determined. Blood oxygen equilibrium curves (OEC) under standard conditions were constructed, and the oxygen exchange fraction (OEF) and the amount of oxygen released at the tissue level by 100 ml of blood (OEF Vol%) were calculated. RESULTS: In each breed, partial pressure of oxygen at 50% saturation of hemoglobin (P50) under standard conditions was significantly higher in older than in neonatal calves, indicating a right shift in OEC with age. Venous P50 was significantly lower in neonatal double-muscled calves than in neonatal dairy calves, but arterial and venous P50 were significantly higher in older double-muscled calves than in older dairy calves. In double-muscled, but not in dairy, calves, OEF was significantly higher in older than in neonatal calves. In neonatal calves, OEF Vol% was not significantly different between breeds, but OEF Vol% was significantly higher in older double-muscled calves than in older dairy calves. CONCLUSIONS AND CLINICAL RELEVANCE: The lower OEF in neonatal double-muscled calves, compared with dairy calves, could contribute to the higher sensitivity of double-muscled calves to hypoxia. Blood oxygen affinity decreased with age, but OEF and OEF Vol% were unchanged with age in dairy calves, whereas they increased with age in double-muscled calves.

2,3-Diphosphoglycerate↗

PubMed1999

Lung membrane diffusing capacity, heart failure, and heart transplantation.

The pulmonary diffusing capacity for carbon monoxide (DLCO) is reduced in chronic heart failure and remains decreased after heart transplantation. This decrease in DLCO may depend on a permanent alteration after transplantation of one or the other of its components: diffusion of the alveolar capillary membrane or the pulmonary capillary blood volume (Vc). Therefore, we measured DLCO, the membrane conductance, and Vc before and after heart transplantation. At the time of hemodynamic measurements, the Roughton and Forster method of measuring DLCO at varying alveolar oxygen concentrations was used to determine the membrane conductance, Vc, DLCO/alveolar volume (VA), the membrane conductance/VA and thetaVc/VA (theta = carbon monoxide conductance of blood, VA = alveolar volume) in 21 patients with class III to IV heart failure before and after transplantation, and in 21 healthy controls. Transplantation normalized pulmonary capillary pressure and increased cardiac index. DLCO was decreased before transplantation (7.11 vs 10.0 mmol/min/kPa in controls), but DLCO/VA was normal (1.67+/-0.44 vs 1.71+/-0.26 mmol/min/kPa/L in controls). DLCO/VA remained unchanged after transplantation, because the decrease in Vc (82+/-30 vs 65+/-18 ml before and after transplantation) and thetaVc/VA was not compensated by the changes in membrane conductance (11+/-4 vs 12+/-5 mmol/min/kPa before and after transplantation, respectively) and membrane conductance/VA. We conclude that the decrease in DLCO in patients with chronic heart failure is due to a restrictive ventilatory pattern because their DLCO/VA remains normal; the decrease in the membrane conductance is compensated by the increase in Vc. After transplantation, the decrease in Vc due to normalization of pulmonary hemodynamics is not completely compensated for by an increase in membrane conductance. Because the membrane conductances, measured before and after transplantation, are negatively correlated with duration of heart failure, its abnormal pulmonary hemodynamics may have irreversibly altered the alveolar capillary membrane.

Adult↗

PubMed1999

Diabetes mellitus induces a thickening of the pulmonary basal lamina.

Long-term diabetes mellitus (DM) is characterized by widespread alterations of basal lamina (BL). The purpose of the present work was to verify whether the lung is also a target organ damaged in DM. Electron microscopy was performed on lung and kidney samples (autopsic material) from 6 diabetics and 6 control subjects studying the thickening of BL of different structures (alveolar epithelial BL, endothelial capillary BL, both fused BL, BL of the glomerular capillary endothelium and BL of the renal tubules). The results were as follows: (1) alveolar epithelial BL (mean +/- SD) = 121 +/- 11 nm in controls and 176 +/- 27 nm in diabetics (p < 0.01), (2) endothelial capillary BL = 164 +/- 14 nm in controls and 223 +/- 27 nm in diabetics (p < 0.001), (3) both BL fused = 222 +/- 23 nm in controls and 316 +/- 62 nm in diabetics (p < 0.01), (4) BL of the glomerular capillary endothelium = 374 +/- 44 nm in controls and 626 +/- 249 in diabetics (p < 0.05) and (5) BL of the renal tubules = 602 +/- 94 nm in controls and 1,083 +/- 376 nm in diabetics (p < 0. 05). All parts of the lung are equally affected by DM. The thickening of BL is of the same magnitude in lung and kidney. There is no relationship between the thickening of the lung BL and the known duration and type of DM.

Adult↗

PubMed1999

Pulmonary gas exchange in life-long nonsmoking patients with diabetes mellitus.

In a companion paper, we have found that the alveolar epithelial basal lamina, endothelial basal lamina and both fused were significantly thicker in 6 autopsied diabetics than in 6 control subjects. The purpose of the present work was to assess whether these lesions have detrimental effects on gas exchange. We investigated 20 life-long nonsmoking subjects: 10 healthy subjects and 10 insulin-dependent diabetics. All of them had one to four diabetic complications of the following organs: kidney, retina, nerves or arteries. Their pulmonary gas exchange and their transfer factor were measured at rest and during two levels of submaximal exercise. Spirometric data, specific airway conductance, transfer factor, transfer coefficient, oxygen consumption and arterial blood gases were normal and almost identical in both groups. In conclusion, the thickening of lung basal laminae has no detrimental effect on pulmonary gas exchange in insulin-dependent diabetics with peripheral complications.

Adult↗

PubMed1998

Effects of hyperchloremia on blood oxygen binding in healthy calves.

Three different levels of hyperchloremia were induced in healthy Friesian calves to study the effects of chloride on blood oxygen transport. By infusion, the calves received either 5 ml/kg of 0.9% NaCl (low-level hyperchloremia; group A), 5 ml/kg of 7.5% NaCl (moderate hyperchloremia; group B), or 7.5 ml/kg of 7.5% NaCl (high-level hyperchloremia; group C). Blood was sampled from the jugular vein and the brachial artery. Chloride concentration, hemoglobin content, arterial and venous pH, PCO2, and PO2 were determined. At each time point (0, 15, 30, 60, and 120 min), the whole blood oxygen equilibrium curve (OEC) was measured under standard conditions. In groups B and C, hyperchloremia was accompanied by a sustained rightward shift of the OEC, as indicated by the significant increase in the standard PO2 at 50% hemoglobin saturation. Infusion of hypertonic saline also induced relative acidosis. The arterial and venous OEC were calculated, with body temperature, pH, and PCO2 values in arterial and venous blood taken into account. The degree of blood desaturation between the arterial and the venous compartments [O2 exchange fraction (OEF%)] and the amount of oxygen released at tissue level by 100 ml of bovine blood (OEF vol%) were calculated from the arterial and venous OEC combined with the PO2 and hemoglobin concentration. The chloride-induced rightward shift of the OEC was reinforced by the relative acidosis, but the altered PO2 values combined with the lower hemoglobin concentration explained the absence of any significant difference in OEF (% and vol%). We conclude that infusion of hypertonic saline induces hyperchloremia and acidemia, which can explain the OEC rightward shift observed in arterial and peripheral venous blood.

Animals↗

PubMed1998

Assessment of the lactate biosensor methodology.

The rapid determination of lactate level is useful for clinical emergencies, as in the case of shock conditions or during surgical operations, as well as in numerous cases of respiratory failure, in cardiac or paediatric pathology and during exercise tests. Moreover, it is of prognostic significance in critically ill patients. Photometric methods are slow and, even when performed in good conditions, will give results only 30 min after blood collection, during which time the clinical condition of the patient may change. In this study, we have assessed the lactate biosensor, a method that yields lactate measurements in less than 1 min with only 100 microL of biological fluid. In order to test the validity of this method, we performed comparisons between the Sigma classical enzymatic reference method and two commercially available biosensors: the Ciba-Corning biosensor 865 and the Yellow Springs lactate biosensor. Lactate measurements were performed in heparinized arterial blood samples without antiglycolitic agent (n=71). In order to cover a wide range of lactate levels, samples came from patients admitted to the intensive care unit for severe conditions and patients addressed for bicycle exercise testing. Each whole blood sample was processed in duplicate by both biosensors. For plasma measurement, subsamples of whole blood were centrifuged and the resulting plasma were processed by the biosensors and the Sigma method. Two parameters that can potentially influence lactate measurement were also investigated: haematocrit and total protein levels. The data showed that measurements performed on plasma are satisfactory for both biosensors. For whole blood, the Ciba-Corning device gives accurate results but the Yellow Springs apparatus seriously underestimates lactate levels. This underestimation is strongly influenced by the haematocrit level, so that a correction factor can be calculated (based on the haemoglobin level), which allows accurate "corrected" results to be obtained for whole blood with the Yellow Springs analyser.

Biosensing Techniques↗

PubMed1998

Effect of inorganic ions on the oxyhemoglobin dissociation curve of severely ill patients.

We have shown that administration of inorganic potassium phosphates (Pi) to patients with severe diabetic ketoacidosis was able to increase the P50 (the PO2 necessary to achieve a hemoglobin saturation of 50%) by a non diphosphoglycerate (DPG) mediated effect. This suggests that the oxyhemoglobin dissociation curve (ODC) may be determined not only by pH, temperature, CO2 content and DPG but also by plasmatic ions. In order to test this hypothesis we have determined the ODC on whole blood in two groups of subjects, 49 control subjects with matching age and sex and 49 patients suffering from liver cirrhosis, acute pancreatitis, septic shock and acute respiratory distress syndrome. The patients had many ionic disorders induced either by their diseases or by the applied treatment. The mean ODC of the patients did not differ from the normal values. In contrast, the dispersion of PO2 around the saturations values was increased from 5 to 80% saturation. A forward regression analysis showed that the DPG level and the levels of inorganic phosphates and natrium (Na+) played a significant role in determining the position of the ODC according to the following equation: P50 (mmHg) = 34.5 + 0.225 DPG + 0.62 Pi-0.09 Na+, where DPG is in micromol.gHb-1 and Pi and Na+ in mEq.l-1. In separate experiments we showed that the Bohr effect as expressed in d (log PO2)/dpH amounted to -0.53, -0.46 and -0.42 for SO2 equal to 5%, 50% and 95%, respectively. The corresponding values for the temperature effect was expressed in d (log PO2)/dT amounted to 0.028, 0.024, and 0.020 respectively. The fact that ions play an role in regulating the position of the ODC of patients with ionic disorders may have therapeutical implications, preventive or curative.

Adult↗

PubMed1998

Validation of cardiac echocardiography for measuring cardiac output to be applied for the multiple inert gas elimination technique.

The multiple inert gas elimination technique (MIGET) is being increasingly used in respiratory physiology and pathophysiology. Six inert gases are given as an intravenous infusion then measured in samples of expired air and mixed arterial and venous blood. This requires right-sided catheterization, a procedure that is sometimes ethically inappropriate. The present article reports a method in which inert gas levels in mixed venous blood were calculated, rather than measured, using Fick's law. Echocardiography was used to measure arterial inert gas levels and cardiac output. The method was validated in 11 men scheduled to undergo coronary bypass surgery. Cardiac output was either calculated based on biometrical (C) data or measured using four different methods in random order, namely Fick's law with oxygen (FiO2) or the inert gases (FiIG) as the tracers, thermodilution (TH), and echocardiography (E). Cardiac output values in L.min-1 (mean +/- SD) were as follows: C, 4.99 +/- 0.39; FiO2, 5.44 +/- 0.86; FiIG, 5.55 +/- 0.92; TH, 5.77 +/- 0.88; and E, 5.53 +/- 0.64. No significant differences were found among the four measured cardiac output values, of which the mean was 5.57 +/- 0.70 L/min, a value that was significantly higher than the calculated value. This difference is probably ascribable to the use of dopamine, dobutamine, or epinephrine in six of the 11 patients. A 1 L/min-1 cardiac output error, in either direction, was found to have a marked influence on the distribution of alveolar perfusion at various VA/Q ratios. Conversely, as expected, ventilation distribution was not influenced by cardiac output. In conclusion, echocardiography provides satisfactory cardiac output estimations using the MIGET except in patients with septal hypertrophy, subaortic membranes, a mitral valve prosthesis, or a mitral valve ring.

Adult↗

PubMed1997

Effect of alveolar volume on the interpretation of single breath DLCO.

Single-breath carbon monoxide diffusing capacity in the whole lung (DLCO) and per unit alveolar volume (DLCO/VA), as expressed in percentage of normal values, gave discordant results when VA of the patients was abnormal. It was hypothesized that normal reference values were inappropriate to interpret data collected in such patients. To substantiate this hypothesis, DLCO and DLCO/VA were measured in four groups: (1) normal volunteers in whom both indices were measured at five different VA; (2) patients with high VA; (3) emphysematous patients; and (4) patients with diffuse interstitial lung diseases (DILD). In normal subjects, DLCO increased and DLCO/VA decreased with VA. In patients with overinflated lungs, the percentage of DLCO was more increased than DLCO/VA. In the emphysematous patients, both indices were equally decreased. In patients with DILD, DLCO was significantly more decreased than DLCO/VA in those suffering from a restrictive pattern. Theoretical values were re-calculated taking into account their true VA and using the relationships observed between DLCO, DLCO/VA and VA. The divergences between DLCO and DLCO/VA were strongly minimized. Therefore, the authors suggest the need to correct theoretical formulas in the presence of a restrictive pattern.

Adult↗

PubMed1997

The effects of hypertonic saline in healthy and diseased animals.

In this review, the pharmacological effects of administering hypertonic solutions to both healthy animals and during experimentally induced diseases are considered with a view to understanding the mechanisms behind the possible clinical efficacy of such treatment. The review focuses successively on haemorrhagic shock, endotoxic shock and hypokalaemic metabolic alkalosis. How hypertonic saline solutions affect oxygen transport by haemoglobin is also considered.

Alkalosis↗

PubMed1997

Influence of age and breed on the binding of oxygen to red blood cells of bovine calves.

The influence of somatic growth and genetic selection on the whole blood oxygen equilibrium curve (OEC) was measured under standard conditions in double-muscled and dairy calves during their first 3 mo of life. Crossbreed animals were also investigated. Hemoglobin, 2,3-diphosphoglycerate (DPG), Cl, and Pi concentrations were also measured. The percentage of fetal hemoglobin (HbF) was determined. The influence of exogenous Cl, Pi, and pH on the OEC was also assessed. The PO2 at 50% hemoglobin saturation (P50) increased during somatic growth, probably because of the increase in DPG recorded in double-muscled neonates and to the progressive disappearance of HbF in both breeds. The oxygen exchange fraction (OEF%) was used to assess the combined influence of the OEC shift and OEC shape changes on blood oxygen desaturation under standard conditions, when the PO2 decreases within a physiological range. The OEF% showed an increase during the first month, then a stabilization. The effects of Cl, Pi, and pH in Friesian calves were similar as in adult cattle. Double-muscled neonates had a lower P50, OEF% values, and DPG concentrations and higher hemoglobin and Cl concentrations than Friesian neonates. The Pi concentration and the percentage of HbF were similar in both breeds. The pH and the Cl concentration had significantly less effect on the OEC in double-muscled than in Friesian calves. Crossbreed animals exhibited intermediate parameter values, between those recorded for double-muscled and Friesian calves. All differences between breeds progressively disappeared during the first month. These data show that blood function changes markedly in calves during the first month of life and that genetic selection can alter blood function.

Age Factors↗