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Biomedical subjects

P Duroux

Publications and source records attributed to P Duroux.

At least 109 records · Page 6Linked to original sources
PubMed1984

Effects of five different organic calcium antagonists on guinea-pig isolated trachea.

The relaxant effects of five organic calcium antagonists (nicardipine, diltiazem, PY 108068, verapamil and bepridil) on guinea-pig isolated trachea were tested against contractions induced by acetylcholine, histamine, 5-hydroxytryptamine, potassium chloride (KCl) and tetraethylammonium (TEA) in a medium containing the normal amount of calcium and against calcium dose-response curves in a calcium-free, potassium-enriched medium. These effects were compared with those of spasmolytic or specific acetylcholine or histamine antagonists. In contrast to the other drugs tested, organic calcium antagonists exerted a specific inhibitory effect on KCl- and TEA-induced contractions. Their degree of activity was in the order: nicardipine greater than diltiazem greater than PY 108068 greater than verapamil greater than bepridil. All calcium antagonists inhibited calcium dose-response curves at similar concentrations. Organic calcium antagonists therefore seem to exert a specific inhibitory effect on depolarizing agents in the guinea-pig isolated trachea, unlike other tissues, notably some vascular smooth muscles.

Animals↗
PubMed1984

Effects of a single bolus of urokinase in patients with life-threatening pulmonary emboli: a descriptive trial.

To evaluate hemodynamic, angiographic, and biological effects of a single bolus of urokinase, an open descriptive trial was conducted in a homogeneous group of 14 patients with acute life-threatening pulmonary emboli and without prior cardiopulmonary disease. For every patient the efficacy of the treatment was evaluated by comparing control and posttherapeutic values after the bolus injection of 15,000 IU/kg body weight urokinase (urinary source) administered in 10 min in the right atrium, followed by continuous intravenous full-dose heparin therapy. In two patients clinical status, hemodynamics, vascular obstruction, and biological (fibrinogen and plasminogen levels) parameters remained unchanged. One of these two patients died, making the mortality rate for the whole group 7%. Twelve of 14 patients showed rapid clinical improvement. Evaluation at 12 hr demonstrated significant decreases in pulmonary vascular obstruction (Miller index, 34%), total pulmonary vascular resistances (37%), and fibrinogen and plasminogen levels (41% and 40%, respectively), without any significant change in cardiac index. The hemodynamic sequential measurements performed (1,3, 6, and 12 hr) in seven of the 12 improved patients showed that the greatest percentage of the total hemodynamic improvement occurred within the first 3 hr after bolus administration of urokinase. No severe hemorrhagic complications were observed. Because of its rapid efficacy and its low cost, the bolus technique appeared particularly useful in the treatment of patients with acute life-threatening pulmonary emboli.

Aged↗
PubMed1984

Computation of ventilation-perfusion ratio with Kr-81m in pulmonary embolism.

Diagnostic difficulties occur in pulmonary embolism (PE) during visual analysis of ventilation-perfusion images in matched defects or in chronic obstructive lung disease (COPD). In 44 patients with angiographically confirmed PE and in 40 patients with COPD, the regional ventilation-perfusion ratios (V/Q) were therefore computed using krypton-81m for each perfusion defect, and were displayed in a functional image. In patients with PE and mismatched defects, a high V/Q (1.96) was observed. A V/Q greater than 1.25 was also found in nine of 11 patients having PE and indeterminate studies (studies with perfusion abnormalities matched by radiographic abnormalities). COPD was characterized by matched defects and low V/Q. The percentage of patients correctly classified as having PE or COPD increased from 56% when considering the match or mismatched character to 88% when based on a V/Q of 1.25 in the region of the perfusion defect. This quantitative analysis, therefore, seems useful in classifying patients with scintigraphic suspicion of PE.

Adult↗
PubMed1983

Effects of diltiazem and other Ca2+ antagonists on guinea-pig tracheal muscle.

The effects of diltiazem and 3 other Ca2+ antagonists (verapamil, nicardipine, bepridil) were studied on isolated guinea-pig tracheal preparations which were contracted with several agonists. Assessment of the contractile agonists was performed under physiological conditions as well as in Ca2+-depleted solutions. The order of potency of the contractile agonists was LTD4 greater than ACh greater than 5-HT greater than Hist greater than BaCl2 greater than TEA greater than KCl. The efficacy of the physiological agonists ACh, Hist and LTD4 was moderately depressed in Ca2+-free solutions while the responses to non-specific agonists and 5-HT were markedly reduced. Diltiazem and verapamil reduced basal tone at concentrations greater than or equal to 10(-4) M. Diltiazem displaced all agonist concentration-effect curves to the right. The four Ca2+ antagonists studied had a marked effect on non-physiological agonists as compared to that on physiological agents. Increasing Ca2+ concentration only partially reversed the inhibitory effect of diltiazem.

Airway Resistance↗
PubMed1983

Effect of the Ca2+ antagonist nifedipine on the release of platelet-activating factor (PAF-acether), slow-reacting substance and beta-glucuronidase from human neutrophils.

Ca2+ antagonists such as nifedipine (Nif) inhibit processes that depend on extracellular Ca2+ in many muscular and secretory cells. The effect of Nif on mediator release and Ca2+ uptake by human polymorphonuclear neutrophils (PMN) has been investigated. Nif caused a concentration-dependent inhibition of the Ca2+ ionophore-induced release of platelet-activating factor (PAF-acether), slow-reacting substance (SRS) and to a lesser degree beta-glucuronidase (beta-glu). Nif inhibited the synthesis of PAF-acether rather than its release. Increasing Ca2+ concentration in the bathing medium from 1.3 to 2.8 mM completely reversed the effect of Nif on PAF-acether secretion. Nif at 1 and 5 microM reduced PMN45Ca2+ uptake induced by the Ca2+ ionophore A 23187. These results indicate that the inhibition by Nif of mediator release depends probably on the Ca2+-antagonistic property of the drug. A preliminary ex vivo study suggests that this inhibitory effect on neutrophil functions exists during therapeutic use.

Autacoids↗
PubMed1983

Sodium cromoglycate, verapamil and nicardipine antagonism to leukotriene D4 bronchoconstriction.

1--The effects of nicardipine, verapamil and sodium cromoglycate (SCG) on the increase in pulmonary airway resistance(RAw) and decrease in pulmonary dynamic compliance (CDyn) induced by leukotriene D4 (LTD4) 0.5 micrograms kg-1 and acetylcholine (ACh) 3 micrograms kg-1 were investigated in anaesthetized guinea-pigs. The effects of these three agents on the contractile effects of LTD4 and ACh were tested on isolated tracheal preparations of the guinea-pig. 2--Nicardipine and verapamil (0.3 and 1 mg kg-1), as well as SCG (3 and 10 mg kg-1), partially but significantly inhibited the effects of LTD4 on RAw. Partial inhibition of the effect of LTD4 on CDyn was only observed with verapamil (0.3 and 1 mg kg-1). Nicardipine and verapamil had no effect on ACh-induced bronchoconstriction in vivo. 3--In concentrations higher than 10(-5) M, nicardipine and verapamil inhibited the contractile effects of LTD4 and ACh on guinea-pig isolated trachea. SCG had no effect on this preparation. 4--These results suggest that nicardipine, verapamil and SCG partially reduce the component of bronchoconstriction associated with stimulation of irritant receptors by LTD4. However, the site and mechanism of action of Ca2+-entry antagonists remain uncertain.

Airway Resistance↗
PubMed1983

Diaphragm dysfunction induced by upper abdominal surgery. Role of postoperative pain.

The effects of upper abdominal surgery on diaphragmatic function were studied in 5 patients. During quiet tidal breathing, the volume displacement of the abdomen within the tidal volume (Vab/Vt) and the ratio of abdominal and transdiaphragmatic pressure changes (delta Pab/delta Pdi), taken as an index of the diaphragmatic contribution to the breathing process, decreased significantly on the first postoperative day (p less than 0.001); in 2 patients, a cephalad paradoxical motion of the diaphragm during inspiration was observed. Diaphragmatic dysfunction also occurred during maximal inspiratory efforts as shown by the significant fall in maximal static transdiaphragmatic pressure (Pdimax) and cephalocaudal diaphragmatic displacement on the first (p less than 0.001) and third (p less than 0.001) postoperative days. On the first postoperative day, opiate epidural analgesia did not modify Vab/VT, delta Pab/delta Pdi, and Pdimax. These parameters spontaneously returned towards control values on the seventh postoperative day. We conclude that upper abdominal surgery induces a marked diaphragmatic dysfunction lasting about 1 wk and that it is not suppressed by postoperative pain relief. The mechanism of this dysfunction remains to be determined. It may be the main cause of the postoperative pulmonary restrictive pattern.

Abdomen↗
PubMed1982

[Carpal tunnel syndrome due to mycobacterium bovis BCG (author's transl)].

A 45-year-old woman, previously in good health developed chronic tenosynovitis with carpal tunnel syndrome a few weeks after wounding herself with a Pasteur pipette containing BCG cultures. She had received two injections of triamcinolone in the anterior annular ligament of the right carpa. The patient recovered after twelve months of antituberculous therapy associating isoniazid (300 mg/day), ethambutol (800 g/day), and rifampicine (400 mg/day). This is the first report of BCG tenosynovitis of the hand. The hazards of steroid injections into the tendon sheaths are pointed out.

Antitubercular Agents↗
PubMed1982

Theophylline kinetics and ventilatory flow in bronchial asthma and chronic airflow obstruction: influence of erythromycin.

The kinetics and the effects on the ventilatory function peak expiratory flow rate (PEFR) of a single 600-mg oral dose of theophylline were investigated in 46 adult patients with bronchial asthma (BA) and in 16 adult patients with chronic airflow obstruction (CAO). In the former, theophylline induced an early and potent bronchodilatation (60% rise in PEFR), the kinetics of which correlated with plasma concentration. Theophylline was also effective in patients with CAO, but the magnitude of its bronchodilator effect was less than in those with BA: this was despite plasma concentrations of much the same order. In adult patients with BA (but not with CAO) theophylline plasma levels and bioavailability are higher after simultaneous erythromycin dosing.

Adult↗
PubMed1982

Circulatory transport of oxygen in patients with chronic airflow obstruction exercising maximally.

Twenty patients with chronic bronchitis were exercised maximally on a bicycle ergometer. At exhaustion, arterial partial pressure of O2 (Pao2) decreased and that of CO2 (Paco2) increased in 8 patients (Subgroup 1). Arterial PO2 increased and Paco2 did not change in the remaining 12 patients (Subgroup 2). Forced expiratory volume in one second was lower in Subgroup 1 than in Subgroup 2. The decrease in arterial pH and the response of cardiac output were the same in both subgroups. Mixed venous PO2 decreased to 23 mm Hg or less in all patients in Subgroup 1 and in 3 patients in Subgroup 2; it stayed above 25 mm Hg in the remaining 9 patients. Our data imply that the ventilatory response to exercise is insufficient not only in Subgroup 1 but also in Subgroup 2 where the patients failed to hyperventilate in response to exercise-induced acidosis and that an unused oxygen reserve is still present at exhaustion in some patients with chronic airflow obstruction.

Aged↗
PubMed1982

[Sequential chemotherapy and radiotherapy modalities in small cell lung carcinoma. Preliminary results].

Two non randomized therapeutic trials have been conducted in oat cell carcinoma of the lung with limited disease. The first protocol combined chemotherapy (adriamycin, cyclophosphamide, VM 26, procarbazine) with mediastinal and supra-clavicular radiotherapy in classical fractionation (40 grays in 4 weeks). The second combined a more intensive chemotherapy (adriamycin, VP 16, methotrexate, cyclophosphamide) with an alternating radiotherapy (3 series of 15 grays). All patients received prophylactic brain irradiation. Preliminary results show a 9 month survival rate of 34 per cent and 62.5 per cent respectively. In addition, all patients in the second protocol presented a complete response at the end of the induction treatment. These preliminary data encourage proceeding with this kind of combined treatment.

Antineoplastic Agents↗