Search PubMed⌕ Search

Biomedical subjects

D Douguet

Publications and source records attributed to D Douguet.

25 records · Page 2Linked to original sources
PubMed1986

Time course of muscular blood metabolites during forearm rhythmic exercise in hypoxia.

O2 concentration, PO2, PCO2, pH, osmolarity, lactate (LA), and hemoglobin (Hb) concentrations in deep forearm venous blood were repeatedly measured during submaximal exercise of forearm muscles. Concentrations of arterial blood gases were determined at rest and during exercise. Experiments were conducted under normoxia and hypobaric hypoxia (PB = 465 Torr). In arterial blood, data obtained during exercise were the same as those obtained during rest under either normoxia or hypoxia. In venous muscular blood, PO2 and O2 concentration were lower at rest and during exercise in hypoxia. The muscular arteriovenous O2 difference during exercise in hypoxia was increased by no more than 10% compared with normoxia, which implied that muscular blood flow during exercise also increased by the same percentage, if we assume that exercise O2 consumption was not affected by hypoxia. Despite increased [LA], the magnitude of changes in PCO2 and pH in hypoxia were smaller than in normoxia during exercise and recovery; this finding is probably due to the increased blood buffer value induced by the greater amount of reduced Hb in hypoxia. Hence all the changes occurring in hypoxia showed that local metabolism was less affected than we expected from the decrease in arterial PO2. The rise in [Hb] that occurred during exercise was lower in hypoxia. Possible underlying mechanisms of the [Hb] rise during exercise are discussed.

Adult↗
PubMed1985

[Activity of almitrine bismesylate on pulmonary hemodynamics and on the liberation of prostanoids in the lymph nodes in sheep].

Almitrine Bismesylate (0.25 mg X kg-1) was perfused for 10 minutes into the pulmonary artery of 4 sheep (40 kg) which were anaesthetized, paralysed and ventilated with 50% oxygen in air and prepared according to Staub et al (J. Surg. Res. 19:315, 1975). The preparation was followed for 2 hours baseline and for four hours after perfusion and comparisons made using analysis of variance. We noted a transitory phase marked by a peak of pulmonary vascular resistance (PVR) at 25 +/- 15 minutes due to a rise in mean pulmonary artery pressure PAP from 14 +/- 2 to 23 +/- 5 cm H2O. PO2 fell from 220 +/- 40 to 180 +/- 25 Torr. A stable haemodynamic state was attained after 90 minutes. PAP was slightly above control and PaO2 significantly elevated (230 +/- 30 Torr P less than 0.05). Left atrial pressure, PCO2, pH, and lung lymph flow did not change. The mild stable vasoconstriction associated to a rise in PaO2 at constant ventilation and high PaO2 does not suggest a straightforward role for chemoreceptors. It is compatible with redistribution of VA/Q ratios by local mediators. Lung lymph was assayed for prostanoids using radio immunological methods. A significant rise in 6 keto PGF1 alpha immunoreactivity was found posterior to the haemodynamic peak. HPLC is required to quantify further this rise.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

[Autohistoradiographic study of the pulmonary retention of almitrine bismesylate].

The histo-autoradiographic distribution of labelled Almitrine was quantitatively assessed on semi-fine cuts of rat lung. The experimental set-up consisted of an isolated heart-lung preparation, perfused for two hours with homologous blood containing 10 microCi per ml of H3 almitrine (990 mCi/mM) et 0.1 microCi per ml of C14 almitrine (9.9 mCi/MM). Sequential histological biopsies were made. There was an apparent heterogeneous radioactivity of the tissues overall with no observed increase in fixation with perfusion time (v.i.). Nevertheless the auto-radiograph enabled this conclusion to be rectified by revealing the cause of the heterogeneity, the embolisation of micro-aggregates of the labelled product. After correction was made for this factor the scattering of the fixed radioactivity in the samples was weak. The localisation of the labelled product showed a good stability for the fixed marker in the tissues, and identified the distribution of the tracers H3 and C14, a preferential fixation by alveolar macrophages, type-2 pneumocytes, Clara cells and adipocytes. A remarkable fixation was noted in the cardiac fibres of the pulmonary veins. Amongst the cells of the bronchi, the mucus cells were notably active for the fixation of Almitrine. There was no detectable fixation associated with the nervous tissues and the neuro-epithelial body was not labelled. A sequential analysis showed that only fixation in smooth muscle fibres rose significantly with perfusion time.

Almitrine↗
PubMed1984

Measurement of pulsatile flows and variable volumes by bolus injection of indicator in a model of the pulmonary circulation.

The reliability and accuracy of the bolus injection-dye dilution technique were assessed for a physiological range of frequencies (13-49 min-1) and stroke volumes (60-160 ml) on a glass model where flows and volumes varied as a preset function of time (n = 320). We found that the technique overestimates flow by about 8% with a 95% confidence interval of +/- 10% for one measurement. Mean transit times are accurate within a +/- 7% confidence interval for one measurement. In a time-dependent flow and volume system this technique measures the mean volume as related to time with fluctuations up to +/- 30% around the mean. Results are independent of time and site of injection. The double injection-single sampling technique gives results that are equivalent to those obtained by single injection and sampling of dye.

Humans↗
PubMedDate not supplied

[The effect on gas mixing of a He-O2 mixture in chronic obstructive lung diseases (author's transl)].

In order to estimate the role played by gaseous diffusion in the mixing disorders of chronic obstructive lung disease (COLD), the effect of breathing a gas mixture lighter than air has been studied. Twenty four patients with severe airflow obstruction have been tested in the following way: in a random order they breathed two different mixtures with the same PO2 : air and helium-oxygen (heliox) for 20 min. Ventilation was monitored during the whole of each run; during the 2 last min arterial blood was sampled. While breathing heliox a slight, non-significant, increase in ventilation has been observed with a slight but statistically significant decrease of PaO2 (p less than 0.01), of PaCO2 (p less than 0.05) and increase of pH (p less than 0.01). These changes suggest a slight increase of distribution disorders with alveolar hyperventilation. For these results to be consistent with stratification, improvement of the diffusion due to low density should have been masked by other phenomena; the possible effects of ternary diffusion, increased viscous resistances and change of transfer factor have been looked at. No conclusive evidence has been found of such counter-effects. Therefore it looks unlikely that stratification be the major factor in distribution impairment in COLD.

Adult↗
PubMedDate not supplied

[Critical study of a new method for measuring total CO2 in plasma (author transl)].

A new analyser for total CO2 in blood--Ericsen E-100--has been tested and its performances compared with those of the manometric Van Slyke apparatus. Ericsen E-100 makes it possible to measure very small samples (50 microliter) in a short time (35 s). It appears that Ericsen E-100 underestimates total CO2; the higher the total CO2 the larger the error. Simple improvements are suggested, especially concerning the way injection is performed in the reaction chamber.

Blood Gas Analysis↗