PubMed Health⌕ Search

Biomedical subjects

D Douguet

Publications and source records attributed to D Douguet.

9 recordsLinked to original sources
PubMed1992

Study of kidney and liver viability in the rat after exclusive aortic perfusion using intracellular ATP measurement.

To find whether the liver can be procured after exclusive aortic perfusion, three organ perfusion models were used in three groups of donor rats. Group 1 underwent liver wash-out via the portal vein; in group 2, the kidneys alone were perfused via the aorta; and group 3 underwent simultaneous aortic perfusion of liver and kidneys. All perfusion flow rates in the three groups were adjusted to physiological values. Harvested organs were transplanted and recipient animals were killed 4 h after transplantation to study liver and kidney viability by using intracellular ATP measurement. Liver ATP was lower (P < 0.005) in the portal perfusion group (group 1: 1.396 +/- 0.412) than in the aortic perfusion group (group 3: 2.181 +/- 0.061). Kidney ATP was comparable in groups 2 and 3:1.066 +/- 0.09 vs 1.059 +/- 0.273 (mumol/g) tissue). Liver cooling was quicker with portal perfusion than with the aortic flush (20 degrees C in 20 s vs 15 degrees C in 60 s). Aortic perfusion at a physiologic flow rate has no detrimental effect on renal viability studied by intracellular ATP measurement. We conclude that liver cooling via the aortic route only is a good alternative to portal perfusion and seems to give good preservation. Application of this observation to emergency procurement in humans is still the subject of controversy.

Adenosine Triphosphate↗
PubMed1988

Muscular venous blood metabolites during rhythmic forearm exercise while breathing air or normoxic helium and argon gas mixtures.

The effects of breathing normoxic helium or argon gas mixture on the local muscular metabolism during exercise were compared to those of room air in four healthy subjects. For this purpose, PO2, PCO2, pH, the concentrations of lactate (LA), glucose (Gl) haemoglobin (Hb) and K+ and osmolarity were repeatedly measured in efferent muscular venous blood during 12 min of rhythmic forearm exercise and 16 min of recovery. The time courses and magnitude of the changes in PCO2, pH, [Gl], [Hb], [K+] and osmolarity during exercise and recovery were similar for breathing both the helium and argon gas mixtures. The main finding was that during exercise, the [LA] curve reached a peak value significantly higher by 25% under normoxic helium than under room air or normoxic argon breathing. This rise in [LA] was accompanied by a slight reduction in muscular venous PO2, too small to signify muscular hypoxia. The possibility that this decline in PO2 might be due to a shift in muscular metabolism towards lipid oxidation was confirmed by the lower muscular respiratory quotient observed during helium breathing. However, such a shift did not explain why [LA] rose during this breathing. The probable explanation is that helium facilitates LA diffusion out of the myocytes.

Adult↗
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↗
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↗