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Biomedical subjects

C Saunier

Publications and source records attributed to C Saunier.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Effect of atrial natriuretic peptide on bronchial tone in anesthetized rabbits.

The effect of atrial natriuretic peptide (ANP) on histamine-induced bronchoconstriction was studied in vivo (in normoxic and in hypoxic rabbits) and in vitro. Thirty-two anesthetized rabbits, spontaneously breathing room air or 10% O2, received infusions of ANP (20, 40, or 80 ng/min/kg normoxia; 20 ng/min/kg hypoxia) or the vehicle for 100 min. After 75 min of ANP infusion, bronchoconstriction was induced inhaling histamine; respiratory resistance (Rrs) was measured prior to and until 20 min posthistamine. The results show that the histamine-induced increase in Rrs was significantly reduced by ANP 80 ng/kg/min in normoxia, and by ANP 20 ng/kg/min in hypoxia. In vitro, ANP had no effect on tracheal and bronchial smooth muscle precontracted with histamine or acetylcholine. These results show that ANP can decrease a histamine-induced bronchoconstriction in vivo but not in vitro, suggesting an indirect mechanism of action.

Airway Resistance↗
PubMedDate not supplied

[Intermediates of erythrocyte glycolysis during three days hypercapnia in the dog (author's transl)].

Ten mongrel dogs (mean weight: 27 kg) awake and with an implanted femoral catheter have been maintained for three days in a controlled chamber (10% CO2 and 21% O2). Arterial blood samples, taken before admission and after one, two, four, six, 24, 48 and 72 hours of exposure, allowed to study blood gases and acid-base equilibrium. Glycemia, phosphatemia, erythrocyte concentration of glucose-6-phosphate (G-6-P), fructose-6-phosphate (F-6-P), fructose-1,6-diphosphate (F-1,6-DP), 2,3-diphosphoglycerate (2,3-DPG), pyruvate, lactate and ATP were also titrated by various enzymatic methods. In addition, nine reference subjects were studied in air (without CO2). During the hypercapnia, [H+] rapidly increases to 70 nmol/1, then progressively decreases after 24 hours, while [HCO3-] slowly rises. The glycemia stays high during the whole exposure. There is also an increase in inorganic phosphate, G-6-P and F-6-P, but during the first 24 hours only. F-1,6-DP, pyruvate and lactate remain lowered during the whole exposure. The 2,3-DPG diminishes after the sixth hour. These phenomena, related to the acidosis and probably to the phosphofructokinase inhibition don't arise in the reference subjects. However the latter present after a two and four hour-stay in the chamber a small decrease in pyruvicemia and lactacidemia.

Animals↗
PubMedDate not supplied

[Metabolism during exercise in young men breathing 4% CO2 (author's transl)].

Fourteen young men (on the average 25 years), well trained (maximal oxygen consumption, VO2 max., between 2.7 to 3.5 1) have been studied at two different levels of exercise: 90 and 140 watts (about 40 and 70% of VO2 max.) in chamber, where the atmosphere was regulated. The subjects performed the exercise after a sojourn of six hours in the chamber, at the same level, either in air or in hypercapnic conditions (FICO2: 0.04; FIO2: 0.21); the order of the exercise tests was determined at random. The rise of total ventilation (VE) during exercise in CO2 atmosphere was particularly related to the increased tidal volume (VT). In spite of the larger increase of VE in hypercapnia, CO2 output (VCO2) and respiratory quotient (R) were lower while PaCO2 was elevated (48 at rest and 54 mmHg during exercise). Oxygen consumption during exercise was the same in both conditions. Values of arterial lactic acid concentration were not different at 90 watts level. On the contrary, at the level of 140 watts, the lactic acid concentration was significantly lower in CO2 atmosphere. The well known changes during exercise of other electrolytes (rise of Na+, K+ and total Ca) was similar in air and in CO2. Only the inorganic phosphorus was higher in CO2 atmosphere at 140 watts.

Adult↗
PubMedDate not supplied

[Transient blood modifications of glycolysis in hypercapnic patients with artificial ventilation (author's transl)].

Ten patients with respiratory insufficiency (mean age: 63 years) are studied during the first 12 hours of intubation and assisted ventilation by a strong volumic respirator (Bennett MA1, FIO2: 0.40). Arterial blood samples are taken before, and after 30 min, one, two, four, six and 12 hours of assisted ventilation, for measurement of blood gases, acid-base equilibrium, haemoglobin and haematocrit, and, by various enzymatic methods, of lactate, pyruvate, ATP and 2,3-DPG concentrations. The PaCO2 rapidly decreases from 75 to 44 mmHg within 30 min ventilation. At the same time, SH+] decreases from 50 to 34 nmol/l. This "reventilation alkalosis" is still more marked later on (PaCO2: 34 mmHg; H+: nmol/l at the sixth hour). The mean PaO2 remains to about 70 mmHg during the assisted ventilation. The glycemia varies little and remains at a high level (140 mg%). The arterial blood lactate concentration progressively increases (from 1.6 to 2.5 mmol/l) at the second hour of ventilation, then decreases to 1.8 mmol/l at the 12th hour. The arterial blood pyruvate concentration also increases, with a peak at the fourth hour. The 2,3-DPG concentration significantly increases from the fourth hour on, whilst the blood ATP decrease is already significant at the first hour of assisted ventilation. These transient changes in glycolysis in chronic hypercapnic patients during assisted ventilation are similar to those observed in the dog when PaCO2 is rapidly normalized after a long term hypercapnia.

Adenosine Triphosphate↗
PubMedDate not supplied

[Glycolytic metabolism during muscular excerise in chronic broncho-pulmonary disease without hypoxemia (author's transl)].

Maximum oxygen uptake (VO2 max) was measured in 11 chronic bronchitics without heart failure or hypoxemia at rest and during maximal work load, using a triangular type of excerise with increasing power (30 W/3 min). Glycolysis was studied in these patients during rectangular exercises lasting 10 minutes, in which power was increased by steps from an average value of 45 % to 72 and 94 % of VO2 max. The metabolic response of lactate in blood is similar to normal, during the limited performances of these patients.

Acid-Base Equilibrium↗