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Biomedical subjects

A Frans

Publications and source records attributed to A Frans.

At least 37 records · Page 2Linked to original sources
PubMed1996

Plasmatic ions influence the oxyhemoglobin dissociation curve of patients with chronic obstructive lung disease.

Chronic hypoxemia, carboxyhemoglobin and ionic disorders as induced by drug intake may a priori influence the oxyhemoglobin dissociation curve (ODC) of patients suffering from chronic obstructive lung disease (COLD). We have traced the ODC and related indices on whole blood of 54 normal non smoking subjects and of 54 ambulatory smokers or ex-smokers COLD patients whose the FEV1 was 1.17 +/- 0.45 litres (mean and SD) and the resting PaO2 63.3 +/- 7.7 Torr. In COLD patients HbCO induces a left shift of the ODC according to the following equation: P50 (Torr) = 27.6-0.4 (HbCO-1) where P50 is the PO2 necessary to saturate hemoglobin at 50%. When normalized for HbCO level of 1% there was no difference in the ODC of the two groups. In contrast, the dispersion around the mean was significantly more important in patients than in control subjects from 20 to 90% SO2. We attributed this fact to ionic disorders that were present in 51 out of the 54 patients and were presumably due to drug intake. The P50 (Torr) = -35.55 + 0.325 (Na+) + 0.096(Cl-) + 0.27 (total CO2), r = 0.73, where Na+, Cl- and total CO2 were expressed in mEq/l. We concluded that: 1) hypoxemia was not deep enough in our patients to shift their ODC to the right; 2) plasmatic ions influenced their ODC; 3) and when possible, it is important to correct ionic disorders either by a curative or a preventive approach.

Adult↗
PubMed1995

Effect of preinspiratory maneuver on the single-breath DLCO.

We have observed in some patients with pulmonary disease and normal subjects that the difference between two successive measurements for single-breath DLCO amounted to 10%. By scrutinizing data from these subjects, we observed that they spontaneously changed their preinspiratory maneuver just before inhaling the test gas mixture. The purpose of the present work is to assess the influence of five different preinspiratory maneuvers on DLCO. Nine healthy males were investigated. They performed at random the five following maneuvers: (A) rapid exhalation from functional residual capacity (FRC) to residual volume (RV), (B) rapid exhalation from FRC to RV and long apnea at RV, (C) rapid exhalation from FRC to RV and short apnea at RV, (D) slow exhalation at a constant speed from FRC to RV, and (E) curvilinear exhalation from FRC to RV. The DLCO values after maneuver B were higher than those after the four other maneuvers; there was a significant relationship between DLCO and the duration of the preinspiratory maneuver. The data are best explained by an alteration in the distribution of the inspired gas mixture to areas with different diffusing capacities. In conclusion, the preinspiratory maneuvers must be standardized in order to improve the reproducibility of the single-breath DLCO measurements.

Adult↗
PubMed1994

Effect of cold pressor test on single-breath DLCO in normal subjects.

We hypothesized that the decrease in single-breath diffusing capacity of CO (DLCO) as observed in patients with Raynaud's phenomenon (P.J. Fahey et al. Am. J. Med. 76:263-269, 1984) may be present in normal subjects. Therefore, we examined 31 healthy subjects in two different laboratories. Two series of experiments were performed. In the first series DLCO was measured in 22 volunteers before (twice) and 5, 10, and 30 min after a cold pressor test (CPT), which consisted of immersing both hands in a 12 degrees C water bath for 2 min. In the second series right heart catheterization was performed in nine healthy seated subjects. Cardiac output, mean pulmonary arterial pressure, heart rate, and pulmonary wedge pressure were measured before, during, and 10, 20, and 30 min after the CPT. In every volunteer the CPT induced a decrease in DLCO that was still present 30 min after the test. In the nine catheterized subjects DLCO increased above control values during the CPT and then decreased below control values for 30 min. The CPT had no effect on cardiac output, heart rate, or pulmonary wedge pressure. In contrast, pulmonary arterial pressure and pulmonary vascular resistance increased during the CPT and then became lower than the control values for at least 30 min. In summary, the CPT induced a biphasic evolution of DLCO in normal subjects, being increased during the CPT and decreased after it. Our data are best explained by the West model of the lung. Our data suggest that the pulmonary Raynaud's phenomenon is not specific to patients with primary Raynaud's phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Chloride and inorganic phosphate modulate binding of oxygen to bovine red blood cells.

The influence of Pi and Cl on the equilibrium of oxygen binding to bovine red blood cells was assessed by plotting the whole blood oxygen dissociation curve measured under standard conditions with and without added KCl and K2HPO4. Both salts shifted the oxygen dissociation curve to the right. This effect was more marked at the highest saturation levels. At a given saturation level, the anion-induced shift was linearly related to the concentration of salt added to the blood. Cl had a greater effect than Pi. The relationship between changes in Po2 at 50% hemoglobin saturation (in Torr) and concentrations of ions added (in mmol/l) was equal to 0.0515[Cl] + 0.0302[Pi] (r2 = 0.94; P < 0.001). These changes were not due to the hyperosmolality induced by salt addition, since sucrose added in place of salts was without effect on the measured parameters. The oxygen exchange fraction expressed as percentage of saturation, i.e., the difference in hemoglobin saturation when Po2 decreases from 130 to 40 Torr, was linearly correlated to added anion concentration (in mmol/l) (= 0.102[Cl] + 0.059[Pi] (r2 = 0.95; P < 0.001)). No significant interaction between the anions was observed; their effects were purely additive. This original mechanism of controlling the oxygen affinity of bovine blood may have clinical relevance: Cl and Pi could be used to increase oxygen transport efficiency in hypoxic animals.

Animals↗
PubMed1994

Single breath diffusing capacity for carbon monoxide in stable asthma.

BACKGROUND: Single breath diffusing capacity for carbon monoxide (Dco) is commonly used as a simple method of assessing overall pulmonary gas exchange properties. Studies of Dco in bronchial asthma have yielded conflicting results. OBJECTIVE: To study Dco and to determine the factors influencing Dco in patients with asthma. METHODS: Dco was prospectively measured in 80 consecutive never-smoker patients with uncomplicated stable asthma. The topographic distribution of lung perfusion was determined in 10 asthmatics and 10 controls, with a 133Xe radionuclide scan. RESULTS: The mean (SD) value of Dco was increased to 117 (17) percent of predicted values; individual values were either within or above normal limits; diffusion was also elevated at 116 (19) percent after correction for alveolar volume (transfer coefficient, D/VA). The Dco was not correlated with atopic status, duration of asthma, or results of spirometric tests; there was a weak negative correlation between D/VA and FEV1 or residual volume. There was a better perfusion of the upper zones of the lungs in asthmatics as compared with controls. Among the asthmatics, there was a strong positive correlation between Dco and the apex to base perfusion ratio (r = 0.975). CONCLUSIONS: Dco is normal or high among never smoker patients with uncomplicated asthma; elevated Dco may be attributed to a better perfusion of the apices of teh lungs; the latter could result from two mutually nonexclusive mechanisms: an increase in pulmonary arterial pressure and/or a more negative pleural pressure generated during inspiration as a consequence of bronchial narrowing. The unexpected finding of high Dco should raise the possibility of bronchial asthma in patients with otherwise undiagnosed conditions.

Adult↗
PubMed1993

Comparative study of the oxyhaemoglobin dissociation curve of four mammals: man, dog, horse and cattle.

1. The entire oxygen dissociation curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO2 40 mmHg and T 37 degrees C, varies between 23.8 (+/- 0.8) mmHg for the horse, 25.0 (+/- 1.4) mmHg for cattle, 26.6 (+/- 1.2) for man and 28.8 (+/- 2.6) mmHg for the dog. 3. The higher dispersion of the dog's P 50 is due to difference between breeds; in seven breeds investigated, the P 50 ranges from 25.8 (spaniel) to 35.8 (hound). 4. We noted no sex difference in the four species. 5. The DPG level is confirmed to be low in cattle (< 1 mumol/gHb) as compared to man (13.5 +/- 2.1 mumol/gHb), horse (16.9 +/- 1.1 mumol/gHb) and dog (19.4 +/- 2.8 mumol/gHb). 6. The oxygen exchange fraction defined as the difference in vol% between a pO2 of 80 and 35 mmHg is, respectively, 3.6 (+/- 0.6) vol% for cattle, 4.0 (+/- 0.4) vol% for the horse, 5.5 (+/- 0.5) vol% for man and 6.6 (+/- 1.7) vol% for the dog. 7. The position and shape of the ODC, as well as T, DPG and pH effects, indicate that the haemoglobin of man and dog seem better adapted to O2 delivery as compared to the horse and cattle.

2,3-Diphosphoglycerate↗
PubMed1993

Effect of metabolic acidosis on pulmonary gas exchange of artificially ventilated dogs.

It is well established that metabolic acidosis induces a reduction in alveolar-arterial O2 difference [(A-a)Do2] in artificially ventilated dogs by shifting the oxyhemoglobin dissociation curve (ODC) and/or by improving the distribution of the ventilation-to-perfusion ratio (VA/Q) throughout the lung. To assess the influence of these two factors we examined eight artificially ventilated dogs before and after induction of metabolic acidosis by a perfusion of 0.3 mol HCl. We measured classic indexes of cardiopulmonary function. VA/Q distribution was estimated using the multiple inert gas elimination technique (MIGET). ODC and Bohr effect of each dog were obtained by a dynamic method. Acidosis increased CO2 excretion, respiratory quotient, blood PO2 at 50% saturation, and arterial PCO2 and PO2 with a simultaneous decrease in (A-a)DO2. In seven dogs, the distribution of VA and Q, as assessed by MIGET, was not substantially modified by HCl perfusion. In the eighth dog the distribution of Q and VA became more homogeneous after acidosis. This led us to conclude that the Bohr effect is the most important and most consistently observed factor responsible for the decrease in (A-a)DO2 found in metabolic acidosis. In rare cases the increase in pulmonary arterial pressure may complement this action by improving the distribution of the VA/Q ratio.

Acidosis↗
PubMed1993

Liver transplantation and pulmonary gas exchanges in hypoxemic children.

Hypoxemia in cirrhotic patients is well documented. One of the possible causes of this association seems to be the presence of functional intrapulmonary shunts. The extent of the ventilation/perfusion ratio (VA/Q) abnormalities and their regression after orthotopic liver transplantation has been previously studied in adults by the multiple inert gas elimination technique. We report here a similar study in three children where the hypoxemia was the main indication for early liver grafting, although the liver function was still preserved at that time. Their hypoxemia was almost exclusively caused by a right to left shunt (VA/Q = 0) with a minimal amount of poorly ventilated but well perfused areas (Low VA/Q). This association may explain the poor response of the arterial oxygen pressure to an increased inspired oxygen concentration. Despite these very large VA/Q mismatches, the children underwent successful liver transplantations, resulting in a regression of the intrapulmonary shunt, as demonstrated by multiple inert gas elimination technique, and compatible with a normal life.

Child↗
PubMed1993

[Transient syndrome of acute irritation of the bronchi induced by single and massive inhalation of phthalic anhydride].

As an evaluation, we report the case of a 38-year-old female tanker driver suffering from "Reactive Airway Dysfunction Syndrome" (RADS). Forty-two months before, she accidentally inhaled a high concentration of gaseous phthalic anhydride. She had never transported this kind of substance before. After her accident, she was forbidden to transport any volatile substances that might harm her airways. She immediately felt a burning of the upper airways and started coughing. Three months later, she complained of wheezing, dyspnea at rest as well as chest tightness. She was diagnosed a bronchial asthmatic by her G.P. and was prescribed low doses of Salbutamol and Dipropionate Beclomethasone. At the time of the evaluation, she was asymptomatic except for coughing. All functional tests were normal except for a PD20 of 0.097 mg/ml for histamine, which clearly reveals bronchial hyperreactivity. We diagnosed "Reactive Airways Dysfunction Syndrome" and suggested she increased the intake of the medicine prescribed. When she came back a year later, she was totally asymptomatic and no longer suffered from bronchial hyperreactivity. This favorable evolution may be observed for these kinds of syndromes, usually helped by medication. Nonetheless, she suffered prejudice as she may no longer transport this kind of volatile and irritating substance.

Adult↗
PubMed1992

Reestimation of the effects of inorganic phosphates on the equilibrium between oxygen and hemoglobin.

In a previous paper, published in this journal, we showed that the data obtained in patients with severe ketoacidosis suggest that inorganic phosphates (K2HPO4) can increase their P50 and therefore enhance tissue oxygenation without concomitant alteration of the 2,3 diphosphoglycerate (DPG). In order to test the hypothesis that K2HPO4 could influence the oxyhemoglobin dissociation curve (ODC) by a mecanism which was not DPG mediated we have measured the total ODC on whole blood with and without addition of 13-80 mmol/l of inorganic phosphates. On average, the level of DPG remained unchanged when the P50 with K2HPO4 was significantly higher (p greater than 0.001) (P50 = 29.9 +/- 3.7 mmHg) than when phosphates were not administered (P50 = 25.5 +/- 2.8 mmHg). The relationship between P50 (mmHg) and K2HPO4 (= X mmol/l) was delta P50 = -2.97 10(-3)(X)2 +0.26(X)-0.42 (r = 0.78). Seeing that phosphates have an immediate action on the ODC, we calculated in our ketoacidosis patients, the relationship between the P50, the inorganic phosphates (P(i) in mg%) and the DPG in mumol/gHb. Both factors exert a highly significant effect (p less than 0.001) on the P50, according to the following equation: P50 = 0.35 DPG +0.26 P(i) + 18.92 (r = 0.73). Our data are important in two points. First it is useful to add inorganic phosphates to the treatment of patients with severe ketoacidosis in order to enhance their tissue oxygenation. Second they recall that the ODC is not only determined by the classical effects of temperature, pH and DPG but also by inorganic anions, like phosphates as described by Benesh and Benesh in their pioneering work.

2,3-Diphosphoglycerate↗
PubMed1992

[Role of platelet activating factor and its antagonists in bronchial asthma].

Inhalation of the platelet activating factor (PAF) produces symptoms of bronchial asthma, a disease in which PAF plays an important role. This lipid mediator released by many kinds of cells exerts its effects on blood cells and on cells of the bronchial wall both directly and indirectly. The crucial role played by PAF in the inflammatory cascades explains the current interest in specific PAF antagonists. These antagonists have both bronchodilator and anti-inflammatory properties and act simultaneously as beta-adrenoceptor agonists and corticosteroids. The first clinical trials of PAF antagonists in the treatment of resistant asthma have given results that are interesting but not superior to those obtained with the conventional anti-asthmatic drugs. The indications for PAF antagonists combined with other specific antagonists will soon be determined.

Asthma↗
PubMed1992

[The effect of inhaled salbutamol on pulmonary gas exchange in patients with chronic obstructive bronchopneumopathy].

The aim of this study is to establish whether or not the inhalation of a puff of salbutamol (Ventoline, 100 micrograms) could induce hypoxemia. Twenty-five chronic obstructive pulmonary disease (COPD) patients were investigated. In a first group of 20 patients arterial blood gases and related indices were measured before and 5, 10, 30, 60 and 90 minutes after inhalation of salbutamol. The oxyhemoglobin dissociation curve was traced before and 90 minutes after the drug intake. Except in two subjects in whom salbutamol dramatically improves arterial blood gases, the drug had no effect on the investigated parameters. It is concluded that salbutamol does not affect the blood gases in COPD patients. In this respect the behaviour of COPD patients differs from that of asthmatics in whom salbutamol generally induced hypoxemia.

Administration, Inhalation↗
PubMed1991

[Isolated cough and bronchial asthma].

Over an 18-month period 31 patients (27 female and 4 male) were referred to the ENT department of our clinic for a 1-month to 14-year history of isolated non-productive cough. As ENT examination, including posterior rhinoscopy, was normal, these patients were sent to the pneumology department. Physical examination and X-ray films of the chest were negative, and the patients did not take an angiotensin converting enzyme inhibitor that could have induced this cough. Inhalation of acetylcholine lowered vital capacity by 32 +/- 14% and forced expiratory volume by 34 +/- 16%, a test which is the hallmark of bronchial hyperreactivity. Three patients were atopic. We believe that this cough can be the only manifestation of bronchial asthma. In these patients, cough was suppressed or strongly attenuated by the inhalation, 5 times a day, of salbutamol 200 mg puffs and beclomethasone dipropionate 250 mcg. In addition, the atopic patients were prescribed 10 puffs of sodium cromoglycate per day. Complaints of isolated non-productive cough must always suggest that possibility of bronchial asthma, and a bronchial provocation test must be performed to confirm this diagnosis.

Adolescent↗
PubMed1991

Disappearance of molsidomine effects on pulmonary circulation of patients with chronic obstructive pulmonary disease after a three week treatment.

The effect of oral molsidomine (M) on the pulmonary artery hypertension of patients with chronic obstructive pulmonary disease (COPD) was investigated during an acute study (4 mg once) and after a 3 week-treatment (3 times 4 mg a day), on a double-blind basis in 16 patients, 8 receiving a placebo, and 8 molsidomine. Ventilatory and cardiocirculatory indices were obtained at rest and during exercise. When acutely given, molsidomine reduces the mean pulmonary arterial pressure (PAP), the pulmonary vascular resistance (PVR) and the arterial O2 partial pressure (PaO2), increasing heart rate (HR) as well as the alveo-arterial O2 partial pressure difference (P(A-a)O2). During exercise, pulmonary arterial pressure and pulmonary vascular resistance decrease while heart rate increases without modification of arterial blood gases. After a 3-week treatment, molsidomine no more improves any index but significantly reduces cardiac output during exercise and consequently the O2 delivery to the tissues. The same feature has already been observed for other nitrates. It thus seems inappropriate to prescribe nitrates or nitrate-like drugs to chronic obstructive pulmonary disease patients with a view to lower their pulmonary hypertension.

Blood Gas Analysis↗