Kinetics of endosomal acidification in Dictyostelium discoideum amoebae. 31P-NMR evidence for a very acidic early endosomal compartment.

We have examined the pH of the various endosomal compartments in the amoebae of the cellular slime mould Dictyostelium discoideum. This was accomplished both by fluorescence and by in vivo 31P-NMR methods. The fluid-phase marker, fluorescein-labeled dextran, was fed to the amoebae to report the average pH of their endocytic vesicles. During the progressive loading of successive endosomal compartments, we observed an early acidification down to a minimum value of pH < or = 5.3 after 30 min at 20 degrees C followed by an increase to an average pH of 5.8 when all the endosomal compartments were loaded by the fluid-phase marker. The weak fluorescence intensity of FITC-dextran at acidic pH precluded a more detailed investigation and we checked various phosphonate compounds as potential 31P-NMR pH probes for the endosomal compartments. Two molecules, aminomethylphosphonate and 2-aminoethylphosphonate, were selected for this study because of the large amplitudes of their chemical shift variation with pH (2 and 2.5 ppm, respectively) and their acidic pKs of 5.5 and 6.3, respectively. They were only moderately toxic (IC50% approximately 10 mM) towards both the axenic growth and the differentiation program of Dictyostelium amoebae. Internalization of the two aminophosphonates occurred only through the fluid-phase pinocytosis pathway as revealed by the full inhibition of their entry with 1 mM vanadate or 7.5 mM caffeine, two previously characterized inhibitors of endocytosis in Dictyostelium. We found that in vivo 31P-NMR of amoebae suspensions incubated with the aminophosphonates allowed the detection of three distinct intracellular compartments at pH 4.3, 5.8-6.0 and 7.3. Kinetics of aminophosphonate entry were analyzed and the results allowed us to reconstruct the time course for the acidification sequence during endocytosis. The data are consistent with the hypothesis that in Dictyostelium amoebae phosphonates occupy a highly acidic early endosomal compartment (t1/2 = 18 min; pH 4.3) before reaching a less acidic late endosomal/prelysosomal compartment (pH 5.8-6.0) from where they are immediately transported to, and trapped in, the cytoplasm (pH 7.3).

Increased plasma serotonin in primary pulmonary hypertension.

PURPOSE: Pulmonary hypertension can occur in patients who have disorders associated with altered platelet serotonin storage, including collagen vascular disease and platelet storage pool disease. We tested the hypothesis that primary pulmonary hypertension (PPH) may be also associated with impaired handling of serotonin by platelets, resulting in increased plasma serotonin levels. PATIENTS AND METHODS: We used radioenzymatic assays to measure serotonin in platelets and plasma and serotonin released during in vitro platelet aggregation in 16 patients with PPH, and in 16 normal controls matched for age and sex. Six patients were restudied after heart-lung transplantation to determine whether serotonin abnormalities persisted after pulmonary arterial pressure returned to normal. RESULTS: Patients had decreased platelet serotonin concentration (1.8 +/- 0.6 x 10(-18) mol/platelet versus 3.2 +/- 0.2 x 10(-18) mol/platelet in controls; P < 0.01) and increased plasma serotonin concentration (30.1 +/- 9.2 x 10(-9) mol/L versus 0.6 +/- 0.1 x 10(-9) mol/L in controls; P < 0.001). Serotonin released during in vitro platelet aggregation was higher in patients than in controls. After heart-lung transplantation, platelet serotonin concentrations remained decreased and plasma levels remained increased. CONCLUSIONS: Abnormal handling of serotonin by platelets leading to an increase in plasma serotonin occurs in PPH. The persistent decrease in platelet storage of serotonin after heart-lung transplantation suggests that this platelet abnormality is not secondary to PPH.

Subcutaneous low-molecular-weight heparin fragmin versus intravenous unfractionated heparin in the treatment of acute non massive pulmonary embolism: an open randomized pilot study.

Low-molecular-weight heparins have been extensively investigated in the treatment of deep venous thrombosis but limited data are available concerning their use in pulmonary embolism. In an open, pilot, randomized study, we compare the safety and efficacy of Fragmin, a low-molecular-weight heparin with those of unfractionated heparin in 60 patients with non massive pulmonary embolism (Miller Index < 20). Thirty one patients received unfractionated heparin intravenously and 29 received a fixed dose of 120 Anti-Xa IU/kg of Fragmin administered subcutaneously twice a day for 10 days. There was no pulmonary embolism recurrence nor major bleeding in either group during the treatment period. The decrease in pulmonary vascular obstruction on perfusion lung scan between day 0 and day 10 was 17 +/- 13% in the Fragmin group and 16 +/- 13% in the heparin group (NS). These results indicate that Fragmin may be a safe and effective treatment of submassive pulmonary embolism.

Surgical management of unresolved pulmonary embolism. A personal series of 72 patients.

Chronic thromboembolic pulmonary hypertension (CT-E PH) is a rare and aberrant outcome of acute pulmonary embolism. Because it has become a potentially curable form of pulmonary hypertension, the frequency of recognized cases has increased. We report a case series of 72 patients with CT-E PH evaluated in our institution between 1984 and 1993, and discuss diagnostic clues and therapeutic approaches. All patients complained of dyspnea on exertion, a history of acute thromboembolic event, and lung murmurs were found in 60% and 17% of patients, respectively. The presence of a disorder of coagulation was found in 30% of the patients tested, the most common abnormality being lupus anticoagulant. The key noninvasive study for diagnosis was the lung perfusion scan which showed at least one segmental or larger perfusion defect in all patients. Pulmonary angiography confirmed the diagnosis in all cases, and sometimes associated to intravascular ultrasound imaging, established the feasibility of thromboendarterectomy. Medical therapy included the use of long-term oral anticoagulant, and in the case of lower limb venous thrombosis, inferior vena cava filtration. Finally two surgical procedures were discussed in selected patients: thromboendarterectomy and lung transplantation. Since 1988, eight patients have benefited from lung transplantation (six patients are still alive), and 11 patients underwent thromboendarterectomy which was successful in 9 patients with a dramatic functional and hemodynamic improvement.

Double lung transplantation in situs inversus with Kartagener's syndrome. Paris-Sud University Lung Transplant Group.

En bloc double lung transplantation with bilateral bronchial anastomoses was successfully performed in three patients with complete situs inversus and end-stage Kartagener's syndrome. Dextrocardia was not a technical problem for institution of cardiopulmonary bypass, but a large azygos vein draining the systemic venous return was systematically preserved. The major technical difficulty was restoration of airway continuity, because patients with situs inversus have an inverse direction and length of the main stem bronchi. The right and left main bronchi of the recipients were approached in the aortocaval sinus and transected approximately at 1.5 cm from the carina. The donor right main stem bronchus was divided at its origin and the donor left main stem bronchus was divided proximal to the upper lobe takeoff. The different bronchial angulation was not an obstacle, and airway continuity was reestablished twice with an end-to-end anastomosis and once with a telescopic technique. Because of the midline position of the left atrium and pulmonary artery, the anastomoses with the respective recipient's structures were made as in patients with situs solitus. One patient required a right lower lobectomy because the position of the right side of the heart interfered with lobar expansion. One patient died of obliterative bronchiolitis 36 months after the operation. The remaining two are alive and doing well after 48 and 6 months, respectively.

Comparative outcome of heart-lung and lung transplantation for pulmonary hypertension.

Despite the development of several lung transplantation procedures, the most advantageous for pulmonary hypertension remains controversial. Between 1986 and February 1992, 30 patients with end-stage primary pulmonary hypertension (n = 24), chronic pulmonary embolism (n = 4), and hystiocytosis X (n = 2) underwent heart-lung (n = 21), double lung (n = 8), or single lung (n = 1) transplantation. Indications for double lung transplantation were similar to those for heart-lung transplantation, and the preoperative clinical and hemodynamic parameters were not significantly different between the two groups. There were no intraoperative deaths, but two reoperations were needed for pleural hematoma. Five early deaths were related to graft failure (two heart-lung transplantations), mediastinitis (one heart-lung transplantation), multiorgan failure (one double lung transplantation), and aspergillosis (one double lung transplantation). There was a similar improvement in early (days 0 and 2) and late (6 months postoperatively) right-sided hemodynamic function in patients undergoing heart-lung and double lung transplantation. Three double lung transplant recipients had early and reversible left ventricular-failure. The early postoperative course of the one patient who had single lung transplantation was characterized by severe pulmonary edema, left ventricular failure, and persistent desaturation and later on by moderate pulmonary hypertension and an important ventilation/perfusion mismatch. The pulmonary function results were also similar in the heart-lung and double lung transplantation groups. The overall projected 2- and 4-year survivals were 49% and 41%, respectively, and were not significantly different between the heart-lung and double lung recipients. Results demonstrate that heart-lung and double lung transplantation are equally effective in obtaining early and durable right-sided hemodynamic and respiratory improvement and similar respiratory function. In patients with pulmonary hypertension, double lung transplantation should be preferred to single lung transplantation because of the critical postoperative course and the uncertain long-term results of single lung transplantation.

Prognostic value of pulmonary hypertension in patients with chronic interstitial lung disease referred for lung or heart-lung transplantation.

BACKGROUND: The purpose of this study was to identify precise and reliable prognostic parameters in patients affected by serious chronic interstitial lung disease, who were undergoing screening for lung or heart-lung transplantation. METHODS: Hemodynamic and respiratory function parameters of 67 patients (43 with idiopathic pulmonary fibrosis, 18 with histiocytosis X, and 6 with lymphangioleiomyomatosis) undergoing clinical screening for lung transplantation. RESULTS: Statistical analysis showed that hemodynamic and respiratory function parameters in patients affected by histiocytosis X and idiopathic pulmonary fibrosis were not related to survival time. Moreover, the degree of pulmonary hypertension showed no correlation between respiratory function parameters in all the groups of diseases examined. Patients affected with histiocytosis X, even with higher degrees of pulmonary hypertension, had a better survival rate (p < 0.0005) compared with patients with idiopathic pulmonary fibrosis. CONCLUSIONS: Hemodynamic and respiratory parameters obtained during the clinical screening for lung transplantation do not predict survival and cannot be used as prognostic indicators.

Relaxation of the diaphragm muscle: influence of ryanodine and fatigue.

Relaxation of rat diaphragm was shown to be sensitive to load, as previously described for adult mammalian ventricular muscle, because the time course of isotonic relaxation could be changed by changing the load: the lighter the load, the greater the shortening, the quicker the relaxation. Maximum velocity of isotonic relaxation was linearly related to the extent of shortening (r = 0.90). To quantify the degree of load sensitivity, we measured the tRi, i.e., the ratio of time at which the isometric relaxation of the twitch afterloaded at 50% of the isometric peak active tension began to time at which the isometric twitch was relaxed to 50% of the isometric peak active twitch tension. tRi was 0.76 +/- 0.03 (SE) in control conditions but significantly increased to 0.91 +/- 0.02 after ryanodine, which is an inhibitor of the sarcoplasmic reticulum (SR) function, and to 0.89 +/- 0.03 after fatigue. These results suggest that in adult rat diaphragm, as in cardiac muscle, the load sensitivity of relaxation requires a well-functioning SR and that the relaxation abnormalities observed in fatigued diaphragm are related to a dysfunction of the SR.

[Influence of preload on myocardial relaxation in the rat]. / Influence de la précharge sur la relaxation du myocarde de rat.

Preload, which determines the initial muscle length, has proved to be a basic determinant of the muscle relaxation phase. The mechanical properties of the papillary muscle of Wistar rats (n = 20) were studied at different initial lengths (L): Lmax and 98 p. 100, 94 p. 100, 90 p. 100, 86 p. 100 and 82 p. 100 Lmax. In isometry, the relaxation phase was proportionally less sensitive to a reduction of preload than the contraction phase. When L decreased the peaks of maximal force derivative of the contraction phase (+dF.dt-1 max) and relaxation phase (-dF.dt-1 max) were linearly and significantly lowered at L = 94 p. 100 Lmax and L = 90 p. 100 Lmax respectively. Conversely, in isotonia the relaxation phase was much more sensitive to a reduction of preload than the contraction phase. On a muscle preloaded from 82 p. 100 Lmax to Lmax, the highest max Vr value (i.e. maximal speed of isotonic relaxation) was measured at Lmax, which is the apex of the Starling's isometric curve. When L decreased max Vr decreased linearly and significantly at 94 p. 100 Lmax. In contrast, the maximal speed of contraction (max Vc) increased between Lmax and 94 p. 100 Lmax, became maximal, then significantly decreased beyond 82 p. 100 Lmax. Thus, in the physiological range of the myocardium (Lmax - 85 p. 100 Lmax) the rat papillary muscle tended to maintain its maximal isotonic speed of contraction, or even to increase that speed, whereas the isometric contraction, isometric relaxation and isotonic relaxation phases were early and significantly depressed.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary arterial hypertension of chronic thromboembolic origin; therapeutic indications]. / Hypertension artérielle pulmonaire d'origine thrombo-embolique chronique; indications thérapeutiques.

Chronic thromboembolic pulmonary hypertension is a rare complication of acute pulmonary embolism. The therapeutic approach to the disease is addressed, based on a series of 81 patients referred to our department between 1984 and 1993. Medical treatment associates long-term anticoagulant therapy and, in some cases, inferior vena cava interruption. Two surgical procedures are available in selected patients: lung transplantation and pulmonary thrombo-endareterectomy. Lung transplantation has been performed in 8 patients since 1988 with 6 survivors with a maximal follow-up of 5 years. Twelve patients underwent pulmonary thromboendareterectomy with in 9 patients a dramatic functional and haemodynamic improvement. Chronic thromboembolism should be systematically investigated as the cause of pulmonary hypertension considering that in selected cases, curative surgery is possible.

[Favorable outcome of a severe carcinoid cardiopathy after complete resection of the primary ovarian tumor]. / Evolution favorable d'une cardiopathie carcinoïde sévère après résection complète de la tumeur ovarienne responsable.

Carcinoid heart disease induced by a primary ovarian carcinoid tumor is very uncommon but offers the opportunity to study its specific outcome. Indeed, unlike to other carcinoid syndromes that occur in the setting of liver metastasis, a complete removal of the primary carcinoid ovarian tumor is often possible in such cases. We report a case of severe carcinoid heart disease secondary to a carcinoid ovarian tumor. Its interest is related to the exhaustive assessment of the cardiopathy and its complete regression after removal of the ovarian tumor. This outcome emphasizes the need for a as complete as possible reduction of humoral secretions in carcinoid heart disease by medical or surgical therapies before discussing valve replacement surgery.

[Vasodilator agents in pulmonary artery hypertension of systemic scleroderma]. / Etude des drogues vasodilatatrices dans l'hypertension artérielle pulmonaire des sclérodermies systémiques.

An acute haemodynamic study was carried out prospectively in 6 patients fulfilling the diagnostic criteria of systemic sclerosis with pulmonary arterial hypertension. This study consisted of 7 baseline measurements and the effect of 6 drugs administered intravenously and known for their effects as vasodilators in the literature. These results were compared to those obtained on 44 patients suffering from pulmonary arterial hypertension previously studied at Hospital A.-Béclère. The prostacyclin (PGI2) possesses a very potent vasodilator effect, lowering the total pulmonary vascular resistance by 29% in patients suffering from scleroderma. As well as PGI2 phentolamine and hydralazine seemed to possess an acute vasodilator action which is certainly not negligible.

[Pulmonary arterial hypertension of chronic thrombo-embolic origin. 70 patients]. / Hypertension artérielle pulmonaire d'origine thrombo-embolique chronique. 70 malades.

OBJECTIVES: Chronic thrombo-embolic pulmonary hypertension is a rare and aberrant outcome of acute pulmonary embolism. Because it has become a potentially curable form of pulmonary hypertension, the frequency of recognized cases has increased. We report a case series of 70 patients with chronic thromboembolic pulmonary hypertension evaluated in our institution between 1984 and 1993, and discuss diagnostic clues and therapeutic approaches. RESULTS: All patients complained of dyspnoea on exertion. A history of acute thrombo-embolic events and lung murmurs were found in 60% and 17% of patients respectively. Coagulation disorders were found in 30% of the patients tested; the most common abnormality was lupus anticoagulant. The key non-invasive study for diagnosis was the lung perfusion scan which showed at least one segmental or wider perfusion defects in all patients. Pulmonary angiography confirmed the diagnosis in all cases and, sometimes associated with intravascular ultrasound imaging, established the feasibility of thromboendarterectomy. Medical therapy included the use of long-term oral anticoagulant, and in case of lower limb venous thrombosis, inferior vena cava filtration. Finally two surgical procedures were discussed in selected patients: thromboendarterectomy and lung transplantation. Since 1988, eight patients have benefited from lung transplantation (six patients are still alive) and 11 patients underwent thromboendarterectomy which was successful in 9 patients leading to dramatic functional and haemodynamic improvement. CONCLUSION: Chronic thrombo-embolic pulmonary hypertension is a severe, sometimes fatal, disease which can be successfully treated by pulmonary thromboendartectomy and lung transplantation.

[Primary pulmonary artery hypertension (data of the literature and personal experience with 25 cases in 10 years)]. / Hypertension artérielle pulmonaire primitive (données de la littérature et expérience personnelle sur 125 cas en 10 ans).

Primary pulmonary hypertension (PPH) is an uncommon disease, of unknown cause. Patients are usually young with a slight predominance in females. We report our experience of 125 patients over 10 years and it is compared to the data of the literature. Epidemiology, physiopathology, clinical and hemodynamic features are reported. Therapeutic aspects are discussed, pointing out on more recent approaches like vasodilating drugs, lung and heart-lung transplantation. Prognosis and survival are presented.

[Acute infectious pneumopathies in adults: methods of identifying the causative agent]. / Pneumopathies infectieuses aiguës de l'adulte: méthodes d'identification de l'agent causal.

Many sampling methods have been proposed to make a bacteriological diagnosis of community-acquired pneumonia. The diagnostic accuracy of these methods depend upon technical constraints which are hardly obtainable in real world situations. In hospitals, close cooperation between clinicians and bacteriologists can help improve the reliability of these techniques, but in current practice the benefits of bacteriological identification often compete with the empirical therapeutic approach. This approach must remain within defined limits, since its uncontrolled widening can lead to major drawbacks. Whenever possible, bacteriological identification of the offending organism must be of concern.