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Nicolas Bonnet

Publications and source records attributed to Nicolas Bonnet.

At least 19 recordsLinked to original sources

Cardiomyopathy related to antimalarial therapy with illustrative case report.

The antimalarial agents, chloroquine (CQ) and hydroxychloroquine (HCQ) are used in long-term treatment of connective tissue diseases and dermatological disorders and are generally regarded as safe. We present one case of cardiotoxicity in a 59-year-old woman treated with antimalarials during 13 years for a discoid lupus erythematosus. She progressively developed conduction disturbances and congestive heart failure (CHF). When the diagnosis of antimalarials toxicity was suspected, CQ was withdrawn. However, heart transplantation had to be performed in the following 4 months for severe CHF. Indeed, rare but severe cardiotoxicity may develop following prolonged use of antimalarials with both conduction disturbances (45 patients) and CHF (25 patients). These cardiac toxic effects have been reported with CQ and less frequently with HCQ use alone. Diagnoses are often delayed since the toxicity of the drug might be misattributed to other factors in these patients. The endomyocardial biopsy, or in some cases the muscle biopsy, are essential to confirm the antimalarials toxicity. Antimalarials have been stopped in 12 cases of CHF, leading to improvement in 8 cases (within 3 months to 5 years) and to deaths or to heart transplantation in 4 cases (within 1 week to 3 months). In the latter cases, as in our patient, the lack of improvement may have been explained by the severity of the cardiomyopathy at diagnosis and the short delay since withdrawal. As a consequence, the potential for reversibility and the severity in undiagnosed cases of these toxic cardiomyopathies emphasize the importance of recognizing early signs of toxicity in order to withdraw antimalarials before the occurrence of life-threatening CHF.

Antimalarials↗

Chronic dissection of the ascending aorta: surgical results during a 20-year period (previous surgery excluded).

OBJECTIVE: We study here the surgical results of chronic dissection involving the ascending aorta over the last 20 years. Patients with previous cardiac surgery, or proximal aortic repair, were excluded. The patients survived an acute dissection, undiagnosed as pauci- or asymptomatic. The aorta was normal or pathological (atheromatous aneurysm in 15 cases, Marfan's disease in 12 cases, and annuloectasic disease in 18 cases). Two patients had a bicuspid aortic valve. METHODS: Between January 1981 and December 2001, 77 patients (mean age 48+/-15) underwent surgery for chronic dissection of the ascending aorta; 60 patients had severe aortic regurgitation, 12 had Marfan syndrome, and 18 had annuloaortic ectasia. Only the ascending aorta was dissected in 37 patients, the ascending aorta and arch in 26, and the whole aorta in 14. Coronary artery disease occurred in five patients. Statistical analysis was performed using SAS software. Different surgical procedures were used. The aortic arch was repaired in 40 cases; selective antegrade cerebral perfusion and partial circulatory arrest were used. Total aortic replacement was performed on four patients. RESULTS: In-hospital mortality was 10%. The only risk factor was the extent of the dissection. The rate of neurologic stroke was 2.5%. Late survival rate was 42+/-7.5% at 12 years for all the patients; it was 71+/-10% when only the ascending aorta was dissected, 44+/-11% when the ascending aorta and arch were dissected, and 33+/-15% when the whole aorta was dissected (p = 0.0329). The extent of the dissection was the only risk factor for late mortality. Reoperation was required for one proximal and five distal problems. CONCLUSION: In chronic aortic dissection, in-hospital and late mortality were related to the extent of the dissection; in-hospital mortality remained unchanged during the operative period.

Adult↗

Aortic prosthetic ring annuloplasty: a useful adjunct to a standardized aortic valve-sparing procedure?

OBJECTIVE: Dilation of aortic annulus, sinuses of Valsalva, and sinotubular junction (STJ) diameters are the characteristic lesions of aortic root aneurysm. The remodeling technique reduces STJ diameter and creates three neosinuses of Valsalva. Alternatively, the reimplantation technique reduces both annulus and STJ diameters to the detriment of aortic root dynamics. Although the remodeling technique is recognized as the most physiological valve-sparing procedure, aortic annulus dilation may jeopardize its results. A standardized approach that combines an external subvalvular aortic prosthetic ring annuloplasty with the remodeling technique is suggested. METHODS: Eighty-three patients underwent an elective aortic root remodeling procedure, either isolated (group 1, n=34) or combined with an external subvalvular aortic prosthetic ring annuloplasty (group 2, n=49). Preoperative aortic regurgitation was 1.59+/-1.1 (group 1) and 1.97+/-1.3 (group 2) (NS). The aortic annulus was more dilated in group 2 than in group 1 (27+/-2.77 mm vs 26.4+/-2.3 mm, p<0.01). Residual aortic regurgitation > or =grade II was the conversion criteria for aortic valve replacement. RESULTS: Operative mortality was 3.6% (n=3). Intraoperative conversion for valve replacement was 32.7% in group 1 (n=11) versus 4.2% in group 2 (n=2) (p<0.001). In group 1, preoperative annulus diameter was larger for converted than for valve-spared patients (27.6+/-1.7 mm vs 25.2+/-1.5 mm, p<0.02). In group 2, implanted aortic ring significantly reduced annulus diameter (20.6+/-1.8 mm) without significant aortic valve gradient (8.3+/-3 mmHg). Follow-up was 17.2+/-13.4 months (group 1) and 10.41+/-7.95 months (group 2). Reoperation for recurrent aortic regurgitation was 13% in group 1 (n=3) versus 4.2% in group 2 (n=2). Echocardiographic follow-up found residual aortic regurgitation < or =grade I in 17 patients in group 1 (90%) versus 43 patients in group 2 (95.5%) and of grade II in two patients in group 1 (10%) and two patients in group 2 (4.5%). CONCLUSION: The addition of external aortic prosthetic ring annuloplasty improves the remodeling technique's operative reproducibility and short-term results. Therefore, its use as a systematical adjunct to the remodeling procedure is suggested. However, further long-term evaluation comparing this valve-sparing procedure to composite graft replacement should define the best surgical strategy for aortic root aneurysm.

Adolescent↗

Imaging techniques for evaluating bone microarchitecture.

At present, fracture risk prediction in the individual patient relies chiefly on bone mineral density (BMD) measurements. However, many lines of evidence indicate that the decreased bone strength characteristic of osteoporosis is dependent not only on BMD, but also on other factors, most notably bone microarchitecture. Here, we review available tools for characterizing trabecular microarchitecture (in terms of morphology, topology, and texture) and for obtaining 2D and 3D images (using radiography, computed tomography, and magnetic resonance imaging). Bone microarchitecture imaging is a noninvasive method that may improve fracture risk prediction in the individual patient, shed light on the pathophysiology of osteoporosis, and help to monitor the effects of treatments. Among the various methods available to date, magnetic resonance imaging has the advantage of involving no radiation exposure, although its limited availability restricts its usefulness for studying vast populations. Regardless of the methods selected to assess bone microarchitecture, there is a need for validated standardized parameters capable of improving fracture risk prediction in longitudinal studies.

Bone Density↗

[Chemical content of street cannabis].

INTRODUCTION: There is little information available about the real content of cannabis consumed in France. OBJECTIVE: To assess the chemical content, including adulterants and contaminants, and potency of cannabis samples obtained from end-users. METHODS: Samples of resins considered by users to produce "unusual" effects were collected from habitual consumers and chemically analyzed. RESULTS: Thirty-seven samples were obtained. Average THC content was 8.8%. The effects reported by users were consistent with the THC content. Apart from an unidentified fatty substance found in two samples, no adulteration was found. DISCUSSION: This study, which relied on volunteers, enabled us to collect samples considered abnormal by experienced users. It did not confirm the numerous anecdotes of adulteration. CONCLUSION: We suggest that this study should be widened to monitor the current chemical contents of cannabis derivatives available in France. The impact of providing users with the results remains to be evaluated.

Cannabinoids↗

[Pharmacy syringe exchange program for injection drug users].

OBJECTIVES: To demonstrate that a syringe exchange program can reduce syringe re-use, to encourage HCV screening by injection drug users (IDUs), and to provide a new harm reduction tool through the pharmacy network. METHODS: Staff at the volunteer pharmacies were trained before participating in this decentralized syringe exchange program based on making the Steribox (with its single-use Sterifilt filter) injection kit available free to IDUs. They were asked but not required to return used material to a waste container in the pharmacy. Pharmacists also informed them of the risk of HCV contamination and encouraged screening. RESULTS: The number of Steribox kits dispensed by the involved pharmacies quadrupled 6 months after the study began, although the number of IDUs using the pharmacy did not increase and kit sales in other local pharmacies did not decease. The disposal rate was almost 80%. The relationship between pharmacists and users clearly improved, and the dispensing of kits has become an opportunity for dialogue. Four participants who injected Subutex accepted referrals to a methadone maintenance treatment program and began treatment. The pharmacists demonstrated their ability to manage this new harm reduction tool. DISCUSSION: The 400% increase in the number of kits dispensed is an indicator of the effect of price on use of sterile injection material. Cost is undoubtedly a factor in syringe re-use. Paid syringes were reused nearly ten times each, compared with 4 times for the free ones. Appropriate disposal was a responsible act that most IDUs performed. The improvement of the relationship between IDUs and pharmacists increased the access of the former to the healthcare system and enhanced the local healthcare network. Referral to the methadone maintenance treatment program was an unexpected and happy result. The dialogue established around injection tools allowed the pharmacists to provide advice as they dispensed Sterifilt and to promote its use by IDUs.

Adult↗

Comparison of synchrotron radiation and conventional x-ray microcomputed tomography for assessing trabecular bone microarchitecture of human femoral heads.

Microcomputed tomography (microCT) produces three-dimensional (3D) images of trabecular bone. We compared conventional microCT (CmicroCT) with a polychromatic x-ray cone beam to synchrotron radiation (SR) microCT with a monochromatic parallel beam for assessing trabecular bone microarchitecture of 14 subchondral femoral head specimens from patients with osteoarthritis (n=10) or osteoporosis (n=4). SRmicroCT images with a voxel size of 10.13 microm were reconstructed from 900 2D radiographic projections (angular step, 0.2 degrees). CmicroCT images with a voxel size of 10.77 microm were reconstructed from 205, 413, and 825 projections obtained using angular steps of 0.9 degrees, 0.45 degrees, and 0.23 degrees, respectively. A single threshold was used to binarize the images. We computed bone volume/ tissue volume (BV/TV), bone surface/bone volume (BS/BV), trabecular number (Tb.N), trabecular thickness (Tb.Th and Tb.Th*), trabecular spacing (Tb.Sp), degree of anisotropy (DA), and Euler density. With the 0.9 degrees angular step, all CmicroCT values were significantly different from SRmicroCT values. With the 0.23 degrees and 0.45 degrees rotation steps, BV/TV, Tb.Th, and BS/BV by CmicroCT differed significantly from the values by SRmicroCT. The error due to slice matching (visual site matching +/- 10 slices) was within 1% for most parameters. Compared to SRmicroCT, BV/TV, Tb.Sp, and Tb.Th by CmicroCT were underestimated, whereas Tb.N and Tb. Th* were overestimated. A Bland and Altman plot showed no bias for Tb.N or DA. Bias was -0.8 +/- 1.0%, +5.0 +/- 1.1 microm, -5.9 +/- 6.3 microm, and -5.7 +/- 29.1 microm for BV/TV, Tb.Th*, Tb.Th, and Tb.Sp, respectively, and the differences did not vary over the range of values. Although systematic differences were noted between SRmicroCT and CmicroCT values, correlations between the techniques were high and the differences would probably not change the discrimination between study groups. CmicroCT provides a reliable 3D assessment of human defatted bone when working at the 0.23 degrees or 0.45 degrees rotation step; the 0.9 degrees rotation step may be insufficiently accurate for morphological bone analysis.

Femur Head↗

The mode of bone conservation does not affect the architecture and the tensile properties of rat femurs.

The bone samples used in clinical and experimental trials must be the less damaged as possible to avoid alterations of their properties. However, the mode of storage might possibly alter the bone properties, particularly microarchitecture and strength. The aim of our study was to analyze the effects of deep-freezing and alcohol conservation techniques on the densitometric, microarchitectural and biomechanical parameters of rat femurs. The left femurs were elongated in uniaxial tension up to breakdown in order to calculate biomechanical parameters. The densitometric and microarchitectural properties of right femurs were evaluated using dual-energy X-ray absorptiometry and microcomputed tomography, respectively. Results showed no significant difference in the parameters investigated between deep-freezing, alcohol storage and fresh femurs when comparing each parameter separately. Therefore, one month storage in alcohol or deep-freezing seemed to induce no harmful effect on densitometric, microarchitectural and biomechanical parameters of rat femurs.

Animals↗

Influence of hypoxia on the domiciliation of mesenchymal stem cells after infusion into rats: possibilities of targeting pulmonary artery remodeling via cells therapies?

BACKGROUND: Bone marrow (BM) cells are promising tools for vascular therapies. Here, we focused on the possibility of targeting the hypoxia-induced pulmonary artery hypertension remodeling with systemic delivery of BM-derived mesenchymal stem cells (MSCs) into non-irradiated rats. METHODS: Six-week-old Wistar rats were exposed to 3-week chronic hypoxia leading to pulmonary artery wall remodeling. Domiciliation of adhesive BM-derived CD45- CD73+ CD90+ MSCs was first studied after a single intravenous infusion of Indium-111-labeled MSCs followed by whole body scintigraphies and autoradiographies of different harvested organs. In a second set of experiments, enhanced-GFP labeling allowed to observe distribution at later times using sequential infusions during the 3-week hypoxia exposure. RESULTS: A 30% pulmonary retention was observed by scintigraphies and no differences were observed in the global repartition between hypoxic and control groups. Intrapulmonary radioactivity repartition was homogenous in both groups, as shown by autoradiographies. BM-derived GFP-labeled MSCs were observed with a global repartition in liver, in spleen, in lung parenchyma and rarely in the adventitial layer of remodeled vessels. Furthermore this global repartition was not modified by hypoxia. Interestingly, these cells displayed in vivo bone marrow homing, proving a preservation of their viability and function. Bone marrow homing of GFP-labeled MSCs was increased in the hypoxic group. CONCLUSION: Adhesive BM-derived CD45- CD73+ CD90+ MSCs are not integrated in the pulmonary arteries remodeled media after repeated intravenous infusions in contrast to previously described in systemic vascular remodeling or with endothelial progenitor cells infusions.

Animals↗

Reoperation for false aneurysm of the ascending aorta after its prosthetic replacement: surgical strategy.

BACKGROUND: This study analyzes surgical approaches of 29 operations carried out for false aneurysms of the ascending aorta after prosthetic replacement (FAA) from January 1979 to April 2003, in 28 patients. METHODS: Initial operations consisted of a composite valve graft with reimplantation of coronary arteries (n = 14) or a supracoronary tube (n = 14) with 7 aortic valve replacements. Initial pathology included acute aortic dissection (n = 20), aortic annuloectasia (n = 6), and aortic valvulopathies with concomitant aneurysm of the ascending aorta (n = 2). Resternotomy was performed under the following conditions: femoral artery cannulation in 7, femoral artery and vein cannulation in 6, femoral artery, vein, and carotid artery cannulation in 16 patients of whom 6 patients underwent partial circulatory arrest. The FAA ruptured during sternotomy in 9 cases. Operative intervention consisted of direct simple suture repair (n = 7), complete revision (n = 21), and one isolated reimplantation of the coronary artery. RESULTS: No patients died after FAA rupture during resternotomy. Among the 6 patients who underwent partial circulatory arrest before sternotomy, the FAA ruptured 5 times. Carotid artery cannulation was always justifiable: 2 cases of FAA rupture, 9 cases of aortic arch replacement, and 5 cases with both. The operative mortality was 17.2% (n = 5). Mortality was influenced by the emergent nature of operations (p < 0.05). CONCLUSIONS: The FAA can be surgically managed with acceptable results through a sternotomy using prior femoro-femoral and carotid cannulation. The latter allows for cerebral perfusion in cases of FAA rupture during resternotomy and is of value for the surgical treatment of these complex lesions.

Adult↗

Mitral valve repair for commissural prolapse: surgical techniques and long term results.

OBJECTIVE: The aim of this study was to describe the pattern of lesions responsible for commissural prolapse, the techniques of valve repair and their long-term results. METHODS: Between 1992 and 2004, 128 mitral valve repairs were consecutively performed for commissural prolapse. There were 86 males and 42 females, the median age was 57.5 years (range 14-84 years). Forty-six percent of patients were in NYHA III or IV, mean ejection fraction was 61+/-9.4%. The diagnosis of commissural prolapse was recognized by preoperative echocardiography in 32% of the patients and was revealed by intraoperative inspection of the valve in the other cases. The site of the prolapse was the posteriomedial commissure (n=94), the anterior commissure (n=30) or both (n=4). The aetiologies were: infective endocarditis (n=56), degenerative (n=46), ischemic (n=25), congenital mitral regurgitation (n=1). The commissural prolapse was associated with another mitral valvular lesion requiring a specific treatment in 61 cases (47.7%). An associated procedure was carried out in 45 patients. RESULTS: The operative treatment of the commissural prolapse included: commissural closure 65 (50.8%), leaflet resection 31 (24.2%), transposition or shortening of chordae 19 (14.8%), reimplantation or shortening of papillary muscles 3 (2.3%), and replacement of the commissural area by a partial mitral homograft 10 (8%). In-hospital mortality included three deaths (2.3%) and four patients (3.1%) were reoperated: three pericardial drainages for hemopericardium and one for mediastinitis. During the follow-up, one patient died (0.8%) from myocardial infarction and eight patients (6.3%) were reoperated including six (4.7%) for recurrent mitral regurgitation. After a median follow-up time of 76.9 months (range from 15 days to 160 months), 116 patients (90.1%) were in NYHA I. Echocardiographs showed no or minimal insufficiency in 112 patients (87.5%) and mild or moderate insufficiency in 10 patients (7.8%). CONCLUSIONS: The diagnosis of commissural prolapse is difficult by preoperative echocardiography. The aetiology of the mitral disease is variable (endocarditis, degenerative or ischemic mitral regurgitation). Using a variety of techniques, commissural prolapse can be repaired with excellent clinical and echographic long-term results.

Adolescent↗

Prostate cancer after heart transplantation: unicenter case-control study.

BACKGROUND: We have noted an unexpectedly high incidence of prostate cancer in our heart transplant recipients (HTR). METHODS: We conducted a retrospective review of patients after heart transplantation to investigate the prevalence, treatment, and outcome of prostate cancer diagnosed after systematic screening (study group). We compared them with case-matched HTR (control). RESULTS: Among 702 recipients, 15 patients had elevated prostate-specific antigen (PSA) levels. Fourteen cases of prostate cancer were diagnosed and treated. The median time between transplantation and prostate cancer diagnosis was 73 months. No patient was diagnosed in a locally advanced (>T2) or metastatic stage. Eleven patients (78.6%) received curative treatment. During follow-up (median, 44 months), 1 patient died from prostate cancer. The survival rate between the study and control groups did not differ. CONCLUSION: Routine PSA testing is recommended as a screening test for prostate cancer in patients after heart transplantation. We believe this could also result in detection of early stages of prostate cancer, thus allowing curative treatment, and achieving similar survival to other case-matched HTR with no prostate cancer.

Age Distribution↗

Patients with a body surface area less than 1.7 m2 have a good outcome with the CardioWest Total Artificial Heart.

BACKGROUND: A body surface area (BSA) of 1.7 m2 was considered as the lower limit to implant a CardioWest Total Artificial Heart (TAH). We reviewed our experience with the TAH in patients with a BSA of less than 1.7 m2. METHODS: From April 1986 to May 2003, among 149 patients implanted with a TAH in our institution, 30 had a BSA of less than 1.7 m2 (Group I). Results were compared with the remaining 119 patients (Group II). RESULTS: One patient in Group I experienced a fitting problem and was left with the chest open. Otherwise, in this group, the Day 1 cardiac index averaged 3.6 +/- 0.6 liter/min/m2, which was significantly higher than the 2.8 +/- 0.36 liter/min/m2 observed in Group II. Post-implantation central venous pressure and mean arterial pressure were similar in both groups: 14.7 +/- 3.8 mm Hg vs 14.5 +/- 4 mm Hg and 87 +/- 23 mm Hg vs 88 +/- 19 mm Hg, respectively. In Group I, survival on the device dramatically increased from 9% before 1992, to 36% between 1992 and 1997 and finally reached 75% after then. In the meantime, for the same time periods, global survival to hospital discharge increased from 9% to 36% and reached 50% after 1997. In Group II, global survival to hospital discharge was 25.5% before 1992, 34.6% between 1993 and 1997, and reached 52% thereafter. CONCLUSION: The CardioWest TAH can be used in patients with a BSA between 1.5 m2 and 1.7 m2 with few fitting problems. In this group of patients, results are similar to those obtained in patients with a BSA greater than 1.8 m2.

Adolescent↗

Poor intraoperative blood glucose control is associated with a worsened hospital outcome after cardiac surgery in diabetic patients.

BACKGROUND: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity. METHODS: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity. RESULTS: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7-19.0). CONCLUSION: Poor intraoperative control of blood glucose concentrations in diabetic patients undergoing cardiac surgery is associated with a worsened hospital outcome after surgery.

Aged↗

Alteration of trabecular bone under chronic beta2 agonists treatment.

PURPOSE: beta2 adrenergic agonists are widely used as doping agents. Their side effects on bone, especially microarchitecture, remain unknown. The purpose of this study was to evaluate the effects of chronic clenbuterol and salbutamol treatment on bones of growing rats. METHODS: Twelve-week-old Wistar female rats were divided into three groups: salbutamol (4 mg.kg(-1).d(-1)), clenbuterol (2 mg.kg(-1).d(-1)), and normal saline (0.5 mL.kg(-1).d(-1)) and treated for 6 wk. Proximal tibia and lumbar spine L4 were analyzed by absorptiometry and by 3D microcomputed tomography. Bending and compression tests were used to measure their mechanical properties. RESULTS: After 6 wk, the salbutamol and clenbuterol groups had lower bone mineral density (BMD) in the tibia, proximal tibia, and vertebrae. Trabecular number and bone volume for the vertebrae were lower in animals treated with clenbuterol (Tb.N: -14.31%, P < 0.001; BV/TV: -21.07%, P < 0.001) or salbutamol (TbN: -12.7%, P < 0.001; BV/TV: -19.7%, P < 0.001) than in controls. Mechanical properties of the tibia were affected by clenbuterol with a lower ultimate force (P = 0.02) and a trend in lower energy to ultimate force (P = 0.053). In vertebrae, salbutamol and clenbuterol induced lower ultimate force. Clenbuterol significantly increased muscle mass (+58.83%, P < 0.01) and reduced fat mass (-28.75%, P < 0.01) compared with controls +17.07 and -7.34%, respectively. CONCLUSION: This study shows a negative effect of clenbuterol and salbutamol on the mechanical properties and microarchitecture of trabecular bone. In the clenbuterol group it was notable that the bone loss contrasts with the anabolic effect on muscle mass. Clearly an increase of muscle mass with enhanced bone fragility augments the risk of fractures for humans or animals treated with beta2 agonists as part of a doping regimen.

Adipose Tissue↗