Biomedical subjects
Publications and source records attributed to Olivier Baron.
A 39-year-old woman with a known history of homozygous familial hypercholesterolemia was admitted with chest discomfort. Preoperative echocardiography and coronary angiography showed a heavily stenotic aortic valve as well as a calcific hypoplastic aortic root. Aortic root replacement using an aortic homograft was done.
Schizophyllum commune, a basidiomycete fungus, is a rare cause of mycotic disease. We report here a case of sinusitis in a 35-year-old woman that underscores the value of molecular biology for the diagnosis of this fungal infection.
OBJECTIVES: The aim of the present study was to analyze whether beta3-adrenoceptors (beta3-ARs) were effectively present and functional in the human internal mammary artery (IMA). BACKGROUND: The beta1- and beta2-adrenoceptors classically mediate the relaxant effects of catecholamines in the vessels. In vitro and in vivo studies performed in various animal species described vasodilating effects due to activation of a third beta-ARs subtype (beta3). METHODS: Reverse transcription-polymerase chain reaction analysis, Western blot experiments, and pharmacological studies were carried out in human IMA samples harvested from 27 patients undergoing coronary bypass surgery. RESULTS: The beta3-ARs messenger ribonucleic acid and protein were detected in intact IMA, but were absent in endothelium-free samples. This finding was confirmed by immunohistochemical experiments. In organ baths, a beta3-AR agonist, SR 58611A, induced an endothelium-dependent relaxation of phenylephrine-precontracted IMA rings. This vasodilation was not modified by beta1/beta2-AR antagonists, but was greatly altered in the presence of L-748,337, a selective human beta3-AR antagonist. Moreover, the inhibition of nitric oxide (NO) synthases abolished the beta3-adrenergic vasodilation, suggesting the involvement of a NO-signaling pathway. CONCLUSIONS: Those results demonstrated the presence of beta3-ARs in the endothelial layer of human IMA. The present work highlights the role of beta3-ARs in vasomotor control of IMA and opens new fields of investigation in coronary bypass graft management, heart failure, and hypertension.
We report two successful transcatheter closures of intrahepatic venovenous malformations observed after bidirectional cavopulmonary anastomoses. These malformations were detected immediately after surgery in one case and during a 10-year follow-up in the second case. These intrahepatic venovenous malformations were successfully occluded by the implantation of an Amplatzer atrial septal occluder.
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Postpneumonectomy syndrome is defined as an airway obstruction due to mediastinal shift and rotation after pneumonectomy. A patient who had undergone a left pneumonectomy for bronchial carcinoma 13 years before presented with tension pneumothorax of her remaining lung. Although all factors relevant to the development of postpneumonectomy syndrome were ascertained, the patient had a pneumothorax rather than an airway obstruction. This pneumothorax was treated surgically. The goal of this operation was to reduce the right pleural cavity volume by implanting an intrapleural prosthesis in the pneumonectomy cavity. This treatment is identical to that used for postpneumonectomy syndrome, which allows the right lung to be rejoined with the thoracic wall.
BACKGROUND: We compared the morbidity and mortality rates of patients who had urgent heart transplantation or transplantation after bridging with a ventricular assist device, with the rates of patients whose clinical stability allowed them to wait at home. METHODS: From March 1985 to December 2000, 404 patients underwent heart transplantation in a single center. There were 273 patients with UNOS status 2 (US 2), 103 patients with UNOS Status 1A (US 1A), and 28 patients with UNOS Status 1B (US 1B). We compared the groups retrospectively with respect to pretransplantation status and operative results. RESULTS: Despite more severely impaired hemodynamics and a significantly higher preoperative infection rate in US 1A and 1B patients, there were no statistically significant differences in survival rates among the three groups. Donor sex and age, cytomegalovirus and toxoplasmosis, mismatch rate, ischemic time, method of myocardial protection, and operative technique did not differ statistically among the three groups. Length of intensive care unit stay, postoperative morbidity, first year postoperative rejection rate, and graft occlusive vascular disease rate were statistically similar among the three groups. Although pretransplantation cancer assessment was less complete in US 1A and 1B than in US 2 patients, the late-cancer rate was not statistically different among the three groups. CONCLUSIONS: These data suggest that urgently transplanted patients have both early and long term morbidity and mortality similar to those of patients waiting for transplantation at home or with a ventricular assist device.
BACKGROUND: We have retrospectively studied 254 patients who underwent a bivalvular mechanical mitral-aortic replacement in the cardiovascular and thoracic surgery unit of Nantes from 1979 to 1989. The follow-up was 22 years (1979 to 2001). The last patient was operated on 12 years before the end of the follow-up. METHODS: All mitral prostheses were St. Jude Medical (SJM) bileaflet valves, and the aortic prostheses were 124 monodisc Björk-Shiley valves, 3 Sorin prostheses, and 127 St. Jude Medical bileaflet prostheses. The mean age was 56.8 +/- 8.5 years with a sex ratio equal to 1. Rheumatism as the etiology predominated with 79.5%. Ninety-seven percent of the patients were followed for a total of 2,779 patient-years and a mean of 11.7 years. RESULTS: Operative mortality was 7.08%. Freedom from overall mortality and valve-related mortality at 22 years were 45.7% +/- 3.6% and 73.1% +/- 3%, respectively. The linearized rates of thromboembolic and hemorrhagic events were 1.07% and 0.9% per patient-year, respectively. Multivariate analysis showed age (p < 0.002), sex (p < 0.01), and degenerative etiology (p = 0.04) as independent factors of late mortality, and age, sex, degenerative disease, and tricuspid pathology were related to valve-related mortality. CONCLUSIONS: This study shows good results after mechanical mitral-aortic replacement in terms of survival rate and quality of life in surviving patients, and outlines the factors influencing long-term results as compared with isolated mitral valve replacement.
OBJECTIVE: Three myocardial protection techniques were evaluated in a prospective, randomised trial during coronary artery bypass grafts in 69 patients. MATERIAL AND METHOD: Twenty seven patients received intermittent hyperkalaemic undiluted warm blood anterograde cardioplegia (AC), 21 received continuous hyperkalaemic undiluted warm blood retrograde cardioplegia (RC) and 21 received intermittent, hyperkalaemic, diluted cold blood (15 degrees C), anterograde cardioplegia (CC). Assessment criteria were clinical, laboratory and haemodynamic. RESULTS: Groups were homogeneous in terms of age, sex, cardiovascular risk factors, severity of coronary disease, preoperative ejection fraction, and number of bypass grafts performed. The oxygen extraction coefficient, and lactate and troponin production in the coronary sinus on aortic unclamping was not significantly different between the three groups. The base excess was -0.19+/-0.13 in the RC group, -0.18+/-0.52 in the AC group and -2.67+/-0.59 in the CC group (P<0.01 CC vs. AC and CC vs. RC). The priming volume was 1485+/-64 ml (CC), 1317+/-44 ml (RC) and 1318+/-30 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The haematocrit during CPB was 28.9+/-0.9 (CC), 32.5+/-0.8 (RC) and 32+/-0.7 (AC) (P<0.05 CC vs. AC and CC vs. RC). The volume of crystalloid delivered was 735+/-85 ml (CC), 362+/-67 ml (RC) and 357+/-105 ml (AC) (P<0.05 CC vs. AC and CC vs. RC). The incidence of ventricular fibrillation on aortic unclamping was 61.9% (CC), 9.5% (RC) and 0% (AC) (P<0.01 CC vs. AC and CC vs. RC). The transfusion rate, duration of intubation, postoperative troponin level, complication rate and mortality were not significantly different between the three groups. Haemodynamic parameters at H2, H4, H8 did not vary significantly between the three groups. CONCLUSION: These three techniques appear to be comparable in terms of myocardial protection. Anterograde cardioplegia ensures an identical degree of security to retrograde cardioplegia regardless of the coronary lesions, apart from redo lesions. CC requires greater haemodilution of the patients during CPB.
BACKGROUND: Several storage methods using a wide variety of extracellular or intracellular solutions applied either as continuous perfusion, intermittent perfusion, or simple immersion of the heart have been commonly used. We have performed a prospective randomized multicenter study of 70 cardiac transplantation recipients to evaluate the Celsior solution for cardiac preservation. METHODS: Seventy consecutive patients were included in this trial and received a cardiac graft arrested and preserved with Celsior. The first follow-up period was 1 month. The mean age of the recipients was 49 years (range, 28 to 66 years), and 81.7% were male. The main disease was nonobstructive cardiomyopathy (64.3%). The age range of donors was between 14 and 56 years with a mean of 33 years. The majority of grafts (73%) were stored in 1 L of Celsior. A midterm follow-up at 5 years was performed and was 100% complete. RESULTS: The operative mortality (<30-day) rate was 6 of 70 (8.6%). Sixty-three patients (90%) had at least satisfactory hemodynamic measurements on day 2. The first postoperative echocardiograms showed good myocardial performance for 90% of the grafts. Actuarial survival rate at 5 years was 75% +/- 5.1%. CONCLUSIONS: The use of Celsior in cardiac transplantation was safe and very effective. This solution proved very valuable in at-risk patients.
The purpose of this study was to report a single center's experience of 5 new pregnancies following heart-lung transplantation. These 5 pregnancies gave rise to 4 live births. Vaginal delivery occurred at a mean of 38 +/- 1 weeks of amenorrhea (range, 37-39 weeks) and the mean birth weight was 3,143 +/- 757 grams (range, 2,270-3,990 grams). Mean maternal forced expiratory volume in 1 second (%) before, during (sixth month), and after (1 year) pregnancy was 87 +/- 18, 87 +/- 22, and 88 +/- 17, respectively (p = NS). In conclusion, pregnancy after heart-lung transplantation can be associated with a good prognosis for mother and child.
1. The present study was performed to determine the role of Rho-Rho kinase signalling pathway in smooth muscle cells from both healthy and varicose human saphenous vein. 2. The Rho kinase inhibitor Y-27632 inhibited the noradrenaline (NA)-induced contraction in human saphenous veins with IC(50) corresponding to 0.5 microM and 10.9 microM in control and varicose veins, respectively. The maximal amplitude of the NA-induced contraction was smaller in varicose vein compared to control (1263+/-172 mg versus 1974+/-245 mg, P<0.05). 3. In beta-escin permeabilized strips, GTPgammaS induced a rise in tension that was inhibited by Y-27632. The amplitude of the GTPgammaS-induced contraction was smaller in varicose compared to control veins (23.1+/-2.4% versus 41.3+/-2.2%, P<0.002). 4. In smooth muscle cells, Y-27632 induced disassembly of both actin cytoskeleton and extracellular fibronectin matrix. In comparison to control cells, varicose vein smooth muscle cells show decreased actin cytoskeleton organization and reduction of fibronectin matrix deposition. 5. The Rho proteins Rnd1 and RhoA, and Rho kinase 1 are expressed in human saphenous veins. A 2.6 fold reduction of Rho kinase expression was found in varicose veins. 6. These results indicate that RhoA-Rho kinase mediated Ca(2+) sensitization of the contraction and regulated actin cytoskeleton and extracellular fibronectin matrix assembly in human saphenous smooth muscle. The decrease of Rho kinase expression and Rho kinase-dependent functions detected in smooth muscle from varicose veins supports a role of this signalling pathway in the functional alterations of the vein wall occurring in the course of the disease.