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Biomedical subjects

O Gateau

Publications and source records attributed to O Gateau.

At least 19 recordsLinked to original sources
PubMed1995

[Autologous blood donation in obstetrics].

OBJECTIVE: To demonstrate the safety of autologous blood donation in an obstetric practice. METHODS: A total of 2350 pregnant patients were screened for an increased risk of peripartum bleeding. Excluding patients with contraindications, a total of 71 women participated in this autologous blood donation program. Blood was donated in the 35th and 37th weeks of pregnancy. RESULTS: No problems occurred in the course of blood donation. All newborns were found to be healthy; 41 of the 71 patients received peripartum autologous blood transfusions. Homologous blood was not given to any of the patients. CONCLUSION: Our experience demonstrates that autologous blood donation is a safe practice in the setting of obstetrics, when the indications and contraindications are considered. Further studies in larger patient populations are necessary to expand or restrict the indications for autologous transfusion in obstetrics.

Adult↗
PubMed1992

[Respiratory effects of moderate hypothermia (36 degrees C-28 degrees C) in dogs under halothane anesthesia].

Changes in systemic haemodynamic variables (mean arterial pressure, MAP; heart rate, HR; cardiac output, Qc), in oxygen consumption, VO2, and in ventilation (minute ventilation, V; respiratory frequency, f; tidal volume, VT; and arterial blood gases) with particular attention to respiratory times (duration of inspiration, TI; duration of expiration, TE; duration of the breathing cycle, TTOT), to respiratory timing (TI/TTOT) and respiratory drive (VT/TI) were studied during moderate progressive hypothermia (36 degrees C to 28 degrees C) during stable halothane anaesthesia (MAC = 1.5) in six dogs. MAP, HR and Qc decreased; V and f decreased, the decrease in f being correlated with that in temperature (r = 0.66; P < 0.01). Tidal volume did not change. The PaO2 and pHa decreased while PaCO2 increased slightly. The decrease in ventilation was related to changes in respiratory times (TI and TE) which increased (TE more than TI) and in respiratory drive (VT/TI which decreased due to the increase in TI). The relation between VT/TI and TI/TTOT changes was not constant during cooling. Changes in respiratory times and drive could be due to the effect of cold on medullar respiratory control.

Anesthesia, Inhalation↗
PubMed1990

[Respiratory effects of almitrine on various levels of the fraction of inspired oxygen. A study in the anesthetized dog].

The effects of intravenous almitrine under normoxic, hyperoxic, and hypoxic conditions were studied in 5 male beagle dogs (mean weight 15.2 +/- 5 kg) anaesthetized with thiopentone. Plasma concentrations of thiopentone were maintained constant at 27-29 mg.1(-1). Each animal underwent twice the three different experiments, with a lapse of a fortnight between each experiment: a) breathing room air, with intravenous administration of 1 mg.kg-1 almitrine over 30 s, b) breathing room air, then pure oxygen for 15 min, followed by an intravenous administration of 1 mg.kg-1 almitrine over 30 s with the dog still breathing pure oxygen, and c) breathing room air, then progressively less oxygen (FIO2 0.18, 0.16, 0.14, 0.12 for 5 min each), followed by an intravenous administration of 1 mg.kg-1 almitrine over 30 s with the dog still breathing a mixture with 12% oxygen. Tidal volume, respiratory rate, minute ventilation, inspiratory and expiratory duration, arterial pH, PaO2 and PaCO2 were measured respectively in room air, after 100% oxygen, in hypoxia (FIO2 = 0.12), before, 5 and 10 min after the injection of almitrine. Hyperoxia depressed ventilation (-21%), whilst hypoxia stimulated it (+126%), although significantly less than in the awake animal. Almitrine restored the respiratory response to hypoxia, but hyperoxia did not suppress respiratory stimulation due to the drug. It would therefore seem likely that almitrine acts on peripheral arterial chemoreceptors, but also on other structures. The results of this study suggest that almitrine may be useful in restoring the respiratory response to hypoxia during recovery from anaesthesia.

Almitrine↗
PubMed1990

Ventilatory effects of almitrine bismesilate in dogs breathing normoxic, hyperoxic and hypoxic mixtures.

The ventilatory effects of 1 mg.kg-1 i.v. almitrine were studied in five dogs anaesthetized with halothane 2% under conditions of normoxia, hyperoxia and hypoxia. Ventilation (minute ventilation, respiratory frequency, tidal volume, duration of inspiration and expiration, ratio TI/Ttot and VT/TI), Pao2, Paco2, pHa, systemic arterial pressure and heart rate were measured in air before and following almitrine; in air, after inhalation of pure oxygen and after almitrine in hyperoxia; in air, during hypoxia with Fio2 progressively decreased from 0.21 to 0.12 and after almitrine in hypoxia (FIO2 = 0.12). Halothane decreased ventilatory response to hypoxia. Almitrine stimulated ventilation irrespective of the level of oxygenation and restored the ventilatory response to hypoxia. Hyperoxia did not suppress ventilatory action of almitrine whose action is probably partly central. Hypoxia and almitrine did not induce major systemic haemodynamic modification.

Almitrine↗
PubMed1989

Galactosyltransferase activities in mitochondria outer membrane: biosynthesis of galactosylated proteins.

1. Mitochondria outer membranes prepared from mouse livers were purified on a discontinuous sucrose gradient. Control in electron microscopy and marker enzymes assays confirmed purity and homogeneity of this fraction. 2. Purified mitochondria outer membranes exhibited significant UDP-galactose: glycoprotein galactosyltransferase activities when incubated with endogenous or exogenous glycoprotein acceptors in presence of detergent (Nonidet P40). 3. Some properties of two distinct mitochondrial galactosyltransferases, acting respectively on ovomucoid and ovine asialo-mucin were investigated. 4. Transfer of galactose on ovomucoid was maximal for a pH of 7.6 at 33 degrees C whereas asialo-mucin galactosyltransferase exhibited an optimum pH of 5.6 for an optimal temperature of 46 degrees C. 5. These two distinct membrane-bound enzymes were both inhibited by diacylglycerophospholipids whereas lysophospholipids modulated both enzymes in a different way: at 5 mM lysophosphatidylcholine, asialo-mucin galactosyltransferase was slightly stimulated while ovomucoid galactosyltransferase was markedly activated. 6. The most important activating effect on ovomucoid galactosyltransferase was obtained with a phospholipid containing a long aliphatic side chain linked by an ester bond in sn-1 of glycerol, an hydroxyl group or hydrogen atoms in sn-2 and a phosphorylcholine head group in sn-3.

Animals↗
PubMed1989

Effects of ketamine on isolated human bronchial preparations.

The bronchodilator effects of ketamine were examined in human bronchial preparations contracted maximally with histamine, acetylcholine, barium chloride or potassium chloride. Antagonism between ketamine and either histamine or acetylcholine was examined also. Ketamine caused bronchial relaxation irrespective of the constricting agent, and exerted a partial and non-competitive antagonism to histamine and acetylcholine. Propranolol and indomethacin did not inhibit the effect of ketamine, excluding the involvement of beta activation and of prostaglandins.

Acetylcholine↗
PubMed1988

Galactosyltransferase activities in mitochondrial outer membrane: biosynthesis of dolichylmonophosphate-galactose.

Mitochondrial outer membranes were prepared from mouse liver homogenates by swelling purified mitochondria in phosphate buffer and were purified on a discontinuous sucrose gradient. Assays for marker enzymes and controls in electron microscopy confirmed the purity and homogeneity of this subfraction. Mitochondrial outer membranes had significant galactosyltransferase activity when incubated with UDP-[14C]galactose: 14C-labelling was found in products extractable with organic solvents and in a residual precipitate. Addition of exogenous dolichylmonophosphate loaded into phosphatidylcholine liposomes strongly enhanced the incorporation of [14C]galactose into chloroform/methanol (2:1, v/v) -extractable products. Thin-layer chromatography of these 2:1 extracts showed that the increase of [14C]galactose incorporation was attributable to the synthesis of a new galactosylated lipid, 'lipid L'. This 'lipid L' has been purified on silicic acid columns by elution with chloroform/methanol (1:1, v/v). The purified 'lipid L' was labile in acid and released [14C]galactose. It had the same chromatographic behaviour as dolichylmonophosphate-mannose in neutral, acid and alkaline solvent systems. Upon incubation in presence of [3H]dolichylmonophosphate and UDP-[14C]galactose, purified 'lipid L' contained both 3H- and 14C-labelling. 'Lipid L', synthesized by mitochondrial outer membranes, was therefore characterized as dolichylmonophosphate-galactose.

Animals↗
PubMed1987

Purification and properties of a mannosyltransferase solubilized from mitochondrial outer membranes.

The enzyme GDPmannose: dolichyl monophosphate mannosyltransferase has been solubilized and purified from mice liver mitochondrial outer membranes. The purification combines detergent extraction of purified outer membranes using Nonidet P-40, with subsequent ion-exchange chromatography on DEAE-cellulose. At this stage, a 400-fold purification is obtained. The partially purified mannosyltransferase is activated by choline-containing lipids such as phosphatidylcholine, lysophosphatidylcholine and sphingomyelin. The reaction is dependent upon the addition of exogenous dolichyl monophosphate. The sole reaction product has been identified as dolichyl phosphate-mannose. The partially purified mannosyltransferase exhibits a Km of 1.33 microM for GDPmannose. Enzyme activity, eluted from DEAE-cellulose, could be further purified after incorporation into sphingomyelin vesicles containing dolichyl monophosphate followed by a sucrose density gradient centrifugation. The mannosyltransferase activity is completely associated with the liposomes at the top of the gradient. Significant stabilization and purification (approx. 1600-fold) of enzyme activity associated with these liposomes is obtained. Furthermore, the reconstitution of this purified enzyme within specific liposomes provides a good model membrane to investigate the molecular requirement of this mitochondrial mannosyltransferase.

Animals↗
PubMed1987

Screening of degradative enzymes from articular cartilage in experimental osteoarthritis.

Sixteen rabbits were killed 12 weeks after sectioning of the right knee anterior cruciate ligament. The left unoperated knee served as a control. The surface area of fibrillated cartilage from femoral condyles and tibial plateau was evaluated and expressed as a percentage of articular surfaces area. Cartilage from the femoro-patellar surfaces was homogenized for the quantification of several degradative activities, based on the release of digested products. Acid phosphatase, several glycosidases and neutral protease activity from the operated joint cartilage were significantly elevated, while collagenolytic activity was unmodified. The percentage of fibrillated cartilage correlated positively with arylsulfatase, glucosidase and neutral protease but negatively with mannosidase and fucosidase. The results may be consistent with the hypothesis of a sequential degradative process leading to cartilage destruction.

Animals↗
PubMed1986

[Anesthesia and surveillance in intracavitary fulguration for radical treatment of ventricular tachycardia].

Endocavitary fulguration, is a new technique to ablate the arrhythmogenic substrate of chronic ventricular tachycardias (VT). This method is used in patients with ventricular tachycardias of varied etiologies. 47 fulgurations in 36 patients with 40 hemodynamic and 12 myocardial metabolic studies are presented. In cardiopathies, the cardiac performance is altered with an ejection fraction of less than 50% and a ventricular function curve which is in Braunwald zone II. Ablation of the arrhythmia was obtained in 63% of cases. Severe complications were observed in 13% of cases, i.e.: low cardiac output, pulmonary oedema and myocardial ischemia. Three patients died from cardiac failure. Ventricular tachycardia was induced to localize the arrhythmogenic foci to be fulgurated. Ventricular tachycardia led to hemodynamic changes with a high pulmonary capillary wedge pressure and low cardiac output (-21%) which was further lowered under general anesthesia (-42%) due to poor response to tachycardia. Endocardial fulguration per se induced severe but transient (less than 5 minutes) hemodynamic changes and was sometimes complicated by myocardial ischemia and conduction disorders. General anesthesia is necessary to perform endocardial fulguration but cannot be induced with a poor hemodynamic state and with high rate ventricular tachy-arrhythmias. Three criteria are used concerning the anesthetic agents: 1) maintainance of cardiac contractility and baro-reflex efficiency; 2) respect of myocardial oxygen balance; 3) maintainance of excitability during mapping of arrhythmogenic foci. Hemodynamic monitoring is necessary to understand and manage complications due to this new type of therapy.

Adult↗
PubMed1985

Glycosyltransferase activities in liver mitochondria. Phospholipid-dependence of inner membrane mannosyltransferase.

The role of phospholipids in the activity of inner mitochondrial mannosyltransferase was investigated. This enzyme catalyzes the direct transfer from GDP-mannose to lipidic acceptor. Inner mitochondrial membranes from purified mice liver mitochondria are prepared by digitonin treatment. Swelling of mitoplasts leads to the formation of inner membrane vesicles, which are then purified on a discontinuous sucrose gradient. The validity of this fractionation procedure is controlled by measurements of specific enzymatic activities and by electron microscopy. Measurement of mannosyltransferase activity in native inner mitochondrial membranes is unsuccessful, even in the presence of exogenous dolichyl monophosphate. Treatment of inner membranes with specific phospholipid liposomes in the presence of exogenous dolichyl monophosphate is essential in order to measure this enzymatic activity. Addition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and cardiolipin in the presence of Mg2+ results in a high degree of activation of the mannosyltransferase system. Maximal enzymatic activity is obtained with an approximate 3:7 mass ratio of exogenous phospholipid to inner membrane proteins. These experiments establish that sensitivity to activation by phospholipids is an inherent property of inner membrane mannosyltransferase. Another approach to this problem was to reconstitute an in vivo lipidic environment of the inner membrane. The results of this procedure suggest that the activity of inner mitochondrial mannosyltransferase may be subject to modulation by outer membrane lipidic extract treatment.

Animals↗
PubMed1985

Response and sensitivity of guinea-pig airway muscle preparations to 5-hydroxytryptamine during ontogenesis.

Responsiveness (g mm-2) and sensitivity (pD2 value) to 5-hydroxytryptamine (5-HT) were markedly reduced in isolated tracheal and bronchial tissues from guinea-pigs during ontogenesis. Responsiveness of the trachea to 5-HT was depressed much more than that to histamine. Airway preparations from young guinea-pigs of either sex always contracted when exposed to 5-HT, an effect that was blocked by methysergide. Airway muscle preparations from old animals exhibited a wide range of responses to 5-HT, namely, no effect, relaxation or contraction. The contractile effect of 5-HT in tracheal and bronchial preparations from old animals was always blocked by methysergide, whereas, the relaxant effect was not. These results indicate that there are significant alterations in the response to 5-HT receptor stimulation in airway muscle preparations from guinea-pigs during ontogenesis.

Aging↗
PubMed1984

Lactic dehydrogenase isoenzyme electrophoretic patterns in the diagnosis of pleural effusion.

The relative value of each lactic dehydrogenase isoenzyme (iso LDH) was measured by electrophoretic separation in the serum and the pleural fluid of 100 patients. In each case, the cause of the pleural effusion was known. Two types of LDH isoenzyme pattern were found in the serum: a normal type with a low value of LDH 5 and an abnormal type with a high value of LDH 5. This high LDH-5 level is due to an impaired liver function. In the pleural fluid, the electrophoretic patterns of five LDH isoenzymes were found by computerized processing. During congestive heart failure (28 cases) the electrophoretic pattern of the LDH isoenzymes was always similar in the serum and in the pleural fluid (transudative pleural effusion). During thoracic empyema, the relative values of the isoenzymes in the pleural fluid were regularly increasing from LDH 1 to LDH 5. In this situation, the evaluation of LDH 5 appeared to emanate from the increased granulocytes in the pleural fluid. In 22 inflammatory pleural effusions, the relative values of the five isoenzymes were equal. During malignant effusions (35 cases) a high level of LDH 5 was found in 21 patients. LDH 5 is known to be secreted by malignant tissue, and the authors confirmed it by finding a high level of LDH 5 in biopsy specimens of patients with mesothelioma or epidermoid lung cancer (7 cases). Conversely, the level of LDH 5 was low in biopsy specimens from normal lung tissue or benign inflammatory pleuritis (6 cases). Among the 14 patients with low levels of LDH 5 in the pleural fluid during malignant pleural effusion, the authors found the malignant lymphomas (three cases) and the small cell lung carcinoma (five cases). In these cases, the low level of LDH 5 was in agreement with the result of a low level of LDH 5 found in the biopsy of a metastatic liver localization of a small cell lung carcinoma. So the electrophoretic determination of LDH isoenzymes pattern in pleural fluid is a sensitive tool for the management of pleural effusion.

Carcinoma, Squamous Cell↗
PubMed1983

[Iodized contrast media. I. effector action on serum enzymes].

In vitro studies were done to examine the effects of contrast media on blood enzymatic activities. The results observed are very significant: in the most simple cases they result in a competitive or mixed-type type inhibition of these enzymes. In systems which involve two substrates and two products a Bi-Bi ping-pong enzymatic mechanism is transformed in Bi-Bi random enzymatic mechanism.

Contrast Media↗
PubMed1982

Effects of defined synthetic phospholipids on glycosylation processes. Modifications of membrane-bound N-acetylglucosaminyl-transferase and solubilized sialyl-transferase activities.

In this paper, we study effects of phosphatidylcholine synthetic derivatives on two different glycosyltransferasic systems, a membranous mitochondrial N-acetylglucosaminyl-transferase and a solubilized microsomal sialyl-transferase. From all our results, we proved the strong inhibitory effect of lysophosphatidylcholines in these glycosylation processes. We investigated then the relationship between this inhibitory effect and the chemical structure of the studied phospholipids. From this work, it became obvious that the most important inhibitory effect is obtained with a molecule containing a long aliphatic side chain in sn-1 of glycerol, a carbon atom devoid of any large group in sn-2 and an hydrophilic part in sn-3 (specially choline).

Animals↗
PubMed1982

[Nitrous oxide and pressures exerted on the trachea by endotracheal tubes. Study on a tracheal model].

The authors studied the effects of nitrous oxide diffusion, using a tracheal model, on the pressure of several endotracheal tube cuffs. Studies carried out showed an increase in volume and pressure of the cuffs related to time exposure and nitrous oxide concentrations used. Use of a self-controlled pressure cuff or filling the cuff with inspired gas composition should be of value to counteract or to prevent the diffusion effect.

Anesthesia, Inhalation↗