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Biomedical subjects

D Bonnet

Publications and source records attributed to D Bonnet.

At least 91 records · Page 5Linked to original sources
PubMed2001

Prevalence of 22q11 deletion in fetuses with conotruncal cardiac defects: a 6-year prospective study.

OBJECTIVES: Conotruncal malformations (CTMs) are a major feature of 22q11 microdeletion (22qdel). The prevalence of 22qdel in fetuses harboring these defects is unknown. We assessed the prevalence of 22qdel in a population of fetuses with conotruncal cardiac defects. STUDY DESIGN: Consecutive fetuses (n = 261) with a CTM and a normal karyotype were included in the study. All fetuses were screened for 22qdel by means of fluorescent in situ hybridization. RESULTS: A 22qdel was found in 54 fetuses (20.7%). The proportion of 22qdel for each CTM was: tetralogy of Fallot (14/100), pulmonary atresia with ventricular septal defect (11/61), tetralogy of Fallot with absent pulmonary valves (6/16), interrupted aortic arch (10/22), truncus arteriosus (9/29), and complex transpositions of the great arteries (4/33). Additional vascular anomalies were present in 75%. Typical abnormal facial appearance at birth or at autopsy was observed in 80%, and thymus hypoplasia, in 76%. The pregnancy was terminated in 41 of 54 cases, including an intrauterine death in one case. The 22qdel was inherited in 7.7%. CONCLUSION: Prevalence of the 22qdel is high in fetuses with CTMs. The risk of mental retardation associated with the respective risk of cardiac surgery for each type of CTM may strongly influence prenatal counseling.

Abortion, Therapeutic↗
PubMed2001

New inhibitors of iron-containing nitrile hydratases.

There is growing evidence in the literature emphasizing the significance of the post-translational modification of cysteine thiols to sulfenic acids (SOH), which have been found in a number of proteins. Crystallographic and mass spectrometric evidence has shown the presence of this group in an inactive form of the industrially important enzyme nitrile hydratase (NHase). This oxidized cysteine is unique in that it forms part of the coordination sphere of the low-spin iron III at the active site of the enzyme. The presence of this unstable sulfenic group in the active form of NHase is the subject of some controversy. To try to detect this function in NHase, we have studied the inhibitory effect on nitrile hydration of reagents known to react with sulfenic acids. Two NHases were studied, namely, Rhodococcus rhodochrous R312 NHase and Comamonas testosteroni NI1 NHase, and the reagents used were meta-chlorocarbonyldicyano-phenylhydrazone (m-ClCP), 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), and 2-nitro-5-thiocyanato-benzoic acid (NTBA). Following this approach we report three novel inhibitors of NHases. In addition, we report thiocyanate reagents that can be used to monitor NHase activity spectroscopically.

4-Chloro-7-nitrobenzofurazan↗
PubMed2001

Hypertelorism-Microtia-Clefting syndrome (Bixler syndrome): report of two unrelated cases.

The association of Hypertelorism, Microtia and Cleft lip and palate (HMC syndrome, MIM 239800) is a rare condition of autosomal recessive inheritance. A total of seven cases of HMC syndrome in five families have been hitherto reported. Here, we report two unrelated cases and put emphasis on the possible normal psychomotor development in this syndrome.

Child, Preschool↗
PubMed2001

Impaired cardiac adrenergic innervation assessed by MIBG imaging as a predictor of treatment response in childhood dilated cardiomyopathy.

OBJECTIVE: To evaluate the prognostic value of metaiodobenzylguanidine (MIBG) imaging in childhood cardiomyopathy. DESIGN: Prospective cohort study. SETTING: Tertiary referral centre. PATIENTS: 40 children (21 boys, 19 girls; mean (SD) age, 7.0 (5.6) years) with heart failure resulting from idiopathic dilated cardiomyopathy (n = 23) or various other disorders (n = 17). METHODS: At the initial examination, cardiac (123)I-MIBG uptake and release, circulating noradrenaline (norepinephrine) concentration, x ray cardiothoracic ratio, and echocardiographic variables were recorded. Cardiac MIBG uptake was obtained by measuring the heart to mediastinum activity ratio on the planar image obtained four hours after MIBG injection. MIBG washout rate was evaluated using relative decrease in cardiac activity measured at 20 minutes and four hours. Patients were treated with angiotensin converting enzyme inhibitors, diuretics, and digitalis, and were followed up for 12 (10) months. Fifteen patients did not respond to medical treatment (12 heart transplants; three deaths), and 25 did respond (improved or stable). RESULTS: Cardiac MIBG uptake was positively correlated with x ray cardiothoracic index (r = 0.55, p = 0.0008) and echocardiographic left ventricular fractional shortening (r = 0.68, p < 0.0001). Among all the clinical and laboratory variables tested, multivariate discriminant analysis showed that the only independent predictor of an unfavourable outcome was a low MIBG uptake (p < 0.001). Survival curves had a mean threshold value of 1.54 for MIBG uptake. CONCLUSIONS: Impaired cardiac adrenergic innervation is strongly related to adverse outcome in children with dilated cardiomyopathy, independently of the aetiology. MIBG imaging may help to stratify risk in such patients.

3-Iodobenzylguanidine↗
PubMed2001

Quality of life and perceived health status in surviving adults with univentricular heart.

OBJECTIVE: To evaluate the quality of life in patients with univentricular heart and to determine the impact of sociodemographic and clinical characteristics. DESIGN AND SETTING: Retrospective, cross sectional study conducted in a regional paediatric cardiology centre. PATIENTS: The health records of 89 survivors with univentricular heart (median age 21 years; range 17-49 years) were reviewed. Sixty seven answered the Duke questionnaire. Sociodemographic and clinical variables were similar in the responders and non-responders. The impact of sociodemographic and clinical variables on individual Duke's measures was assessed. RESULTS: The Duke scores of adults with univentricular heart were similar to the normal population. Cyanosis predicted a worse score for physical (p = 0.05) and perceived health measures (p = 0.02). A higher educational level predicted a better score for physical (p = 0.004), mental (p = 0.01), and general health measures (p = 0.02). Orthopaedic problems worsened the social score (p = 0.05). Psychosocial problems worsened the pain score (p = 0.04). In comparison with the other anatomical types, mitral atresia worsened the perceived health score (p = 0.02). Patients younger than 23 years scored better for almost all health and dysfunction measures. CONCLUSIONS: Despite repeated interventions and other disease related everyday stresses, a selected group of adults with univentricular heart had a satisfying quality of life.

Adolescent↗
PubMed2001

[Stenosis of the superior caval canal after Mustard and Senning procedures: treatment by dilatation and stent implantation. Two case reports].

The authors report two cases of stenosis of the superior caval canal after Mustard and Senning procedures for transposition of the great arteries in patients paced for atrial arrhythmia. During cardiac catheterisation, it was possible to treat the stenosis by perforation in one case and by balloon dilatation in the second, followed by the implantation of two stents to reestablish vascular patency. In one patient, two pacing catheters were implanted by an endovascular approach without complications three months after stenting; in the other case, epicardial pacing was required because the patient's condition could not wait for endothelialisation of the stent before implanting the pacing catheters. This technique of revascularisation may also be used in children with venous stenosis after implantation of endocavitary pacing catheters, in which the pacing system has to be changed.

Adolescent↗
PubMed2001

Aneurysmal dilation of a pericardial patch prepared with glutharaldehyde and used for closure of a ventricular septal defect.

Pericardium patches are commonly used for the repair of congenital heart diseases. Aneurysmal dilation is a complication specific to the use of pericardial patches. Preparation of the pericardium with glutharaldehyde is considered to avoid this risk. In the present case report, we describe the development of a giant aneurysm of a heterologous patch used for closure of a ventricular septal defect in a child aged 14 days.

Glutaral↗
PubMed2001

[Baloon angioplasty with stent implantation in recoarctation of the aorta: an attractive alternative].

The results of transcatheter balloon angioplasty in teenagers and adults with aortic recoarctation are uncertain. Therefore, there is a current trend to prefer a more complex procedure including the implantation of a stent. This study deals with 8 patients aged 7 to 25.3 years (median: 15 years), weighing 20 to 68 kg. (median: 57) and having undergone resection of an aortic coarctation during infancy (24 days to 4 years). All had their lower limb pulses diminished or abolished, elevated blood pressure at rest (and at exercise in the 5 tested patients), and left ventricular hypertrophy. MRI documented the lesion and helped to select seven patients whose stenosis was short and remote enough from the origin of the main aortic collateral. In one case, the decision to stent was taken as an emergent measure to treat an aortic dissection which appeared shortly after balloon dilatation. The effectiveness of the procedure was immediate in all patients with a 50% increase in diameter of the dilated area, total relief of the gradient, drop to normal values of the blood pressure. These good results persisted at follow-up (3-24 months) in 6 patients, with moderate hypertensive rebounds in the last 2. There were 2 technical problems (premature burst of the balloon, asymmetrical inflation of the stent like an "Eiffel Tower") that could finally be overcome and should no longer occur with the new specially designed so-called "BIB" balloons. Would long term follow-up confirm these early results, one should conclude that this method offers an attractive, safe and effective option to surgery for adolescents and adults with late recoarctation of the aorta.

Adolescent↗
PubMed2001

[Interest in myocardial scintigraphy following the arterial switch procedure for transposition of the great vessels].

Coronary artery obstruction is the main late complication of the so-called arterial switch operation designed to repair transpositions of the great arteries in newborn infants by switching the great vessels and transferring the coronary ostia onto the posterior vessel. Our aim was to study the links between myocardial perfusion and coronary artery anatomy after the arterial switch operation. Forty-five patients (5.863 years) underwent a 201Tl myocardial SPECT and a selective coronary artery angiography. The latter was normal in 20 children: 13 had also a normal myocardial scan but 7 had myocardial perfusion defects including 2 with angina who had a very low coronary reserve at positron emission tomography. Twenty-five patients had severe coronary artery lesions: 5 with a normal myocardial scan and 20 with perfusion defects. Twelve out of these 20 underwent surgical revascularization and the SPECT images went back to normal in all within 6 months after surgery. Specificity and sensitivity of myocardial SPECT in detecting coronary artery lesions were 78% and 69% whereas positive and negative predictive values were 74 and 73%. We conclude that myocardial SPECT imaging is not the right way to detect late post arterial switch coronary artery lesions. It is helpful in decision making as to submit these children to surgical revascularization and in assessing its postoperative effectiveness.

Adolescent↗
PubMed2001

[Quality of life of adults with univentricular hearts].

This study sought to evaluate the quality of life of surviving adults with univentricular heart and to determine the impact of sociodemographic and clinical characteristics on quality of life. The health records of 89 survivors with univentricular heart living in France at the time of the study were reviewed. They were 17 to 49 years old (median: 21). Sixty-seven patients answered the Duke questionnaire. Sociodemographic and clinical variables were similar in the responders and non-responders. The scores of patients who answered the questionnaire were compared with national norms. The impact of sociodemographic and clinical variables on individual Duke's measures was assessed. The Duke scores of adults with univentricular heart were similar to those of the normal population. Cyanosis predicted a worse score for physical (p = .05) and perceived health measures (p = .02). The higher educational level predicted a better score for physical (p .004), mental (p = .01), and general health measures (p = .02). Orthopaedic problems worsened social score (p = .05). Psychosocial problems worsened pain score (p = .04). Mitral atresia, in comparison with the other anatomical types, worsened perceived health score (p = .02). Finally, patients younger than 23 years scored better for almost all of health and dysfunction measures. In conclusion, despite repeated interventions and other disease-related everyday stresses, a selected group of adults with univentricular heart had a satisfying quality of life. These patients probably developed copying mechanisms, easing the psychological stress, and oriented themselves towards a different set of values in everyday life so that to accept disabilities and to recalibrate personal expectations.

Adolescent↗
PubMed2001

[Arterial dysfunction after treatment of coarctation of the aorta].

The long term follow-up after successful coarctation repair has a late cardiovascular morbidity, includes systemic hypertension at rest or/and after exercise. The pathophysiology mechanisms responsible have not been well determined. We studied 70 normotensive subjects at rest (age, 14 +/- 5 y; pressure, 116 +/- 13/56 +/- 9 mmHg), who had an isolated coarctation with a good repair defined by the absence of gradient between upper and lower right limb (0.-26 mmHg). After exercise testing we defined two groups: Coa HT: Hypertension at exercise equal or over 200 mmHg, n = 20 (228 +/- 23 mmHg) and Coa HT: Normotensive at exercise = 10 (163 +/- 24 mmHg). These subjects were mached sex-age and blood pressure to 70 controls (age, 13 +/- 3 y; pressure, 115 +/- 10/56 +/- 6 mmHg). Using a high-resolution echographic technique, we assessed the systolic, diastolic diameter and the intima media thickness (IMT) of the common carotid artery (CCA) to define mechanical indexes: Cross sectional compliance (CSC), distensibility (CSD) and incremental elastic modulus (Einc) in each group. CCA pressure waveform and the local pulse pressure were determined in 32 subjects to define augmentation index (AI). The changes of the brachial artery diameter in response to reactive hyperaemia (flow mediated dilation: FDM) and to glyceryltrinitrate (GTNMD) were measured. The IMT was significantly increased in the Coa group (by 8%, p < 0.001) and higher in the Coa HT group compared with the Coa NT group (0.57 +/- 0.04 mm vs 0.54 +/- 0.05 mm, p < 0.05). The CSD was lower and the Einc was higher in both groups. The carotid pulse pressure amplitude was significantly higher in the Coa HT Group (41 +/- 14 vs 33 +/- 7 mmHg; p < 0.05). The AI was higher in both Coa repair groups. Both flow-mediated dilation (FMD) and GTN-mediated dilation (GTNMD) of the brachial artery were lower in the Coa group (respectively 5 +/- 3 vs 7 +/- 3%; p < 0.01; 16 +/- 8 vs 23 +/- 9%; p < 0.01). GTNMD was inversely correlated with maximum systolic blood pressure on exercise (r = 0.31, p = 0.03). The IMT of the CCA was related to the local pulse pressure in both groups of coarctation repair. The combination of distensibility decrease in the proximal arterial bed with an impairment of distal artery reactivity would account for the elevation of exercise blood pressure in subjects who had coarctation repair. The increase of local pulse pressure influences the carotid wall hypertrophy.

Adolescent↗
PubMed2001

[Treatment of chronic heart failure in the child].

Medical therapy for chronic heart failure has recently been extensively revised on the basis of a reduction of mortality in randomized trials. However, there are almost no available trials in children whose treatment for heart failure is adapted from what is known in adults. Digitalis play a role in heart rate variability but there is no evidence for an effect on mortality. Angiotensin-converting enzyme inhibitors lead to an improvement of left ventricular function and reduces mortality; in addition, they are well tolerated in children. Diuretics are useful in congestive heart failure but chronic administration may have deleterious effects. Beta-blocking agents reduce mortality and improve symptoms and the ejection fraction; however, they must be given cautiously and the up-titration phase must be very progressive. New promising drugs are emerging (calcium sensitizers, phosphodiesterase inhibitors, angiotensin receptor [AT1] blockers) but at the present time their use in chronic heart failure has not proven to be efficient.

Cardiotonic Agents↗
PubMed2000

Percutaneous replacement of pulmonary valve in a right-ventricle to pulmonary-artery prosthetic conduit with valve dysfunction.

BACKGROUND: Valved conduits from the right ventricle to the pulmonary artery are frequently used in paediatric cardiac surgery. However, stenosis and insufficiency of the conduit usually occur in the follow-up and lead to reoperations. Conduit stenting can delay surgical replacement, but it aggravates pulmonary insufficiency. We developed an innovative system for percutaneous stent implantation combined with valve replacement. METHODS: A 12-year-old boy with stenosis and insufficiency of a prosthetic conduit from the right ventricle to the pulmonary artery underwent percutaneous implantation of a bovine jugular valve in the conduit. FINDINGS: Angiography, haemodynamic assessment, and echocardiography after the procedure showed no insufficiency of the implanted valve, and partial relief of the conduit stenosis. There were no complications after 1 month of follow-up, and the patient is presently in good physical condition. INTERPRETATION: We have shown that percutaneous valve replacement in the pulmonary position is possible. With further technical improvements, this new technique might also be used for valve replacement in other cardiac and non-cardiac positions.

Angiography↗
PubMed2000

Transcatheter implantation of a bovine valve in pulmonary position: a lamb study.

BACKGROUND: Pulmonary regurgitation can lead to severe right ventricular dysfunction, which is a delicate postoperative problem in the long-term follow-up of patients who had surgery for congenital heart diseases. Clinical conditions of patients suffering from pulmonary valve incompetence are improved by valve replacement with a prosthetic valve. To date, the surgical approach is the only option to replace a pulmonary valve. We report the first experience of percutaneous pulmonary valve implantation. METHODS AND RESULTS: A fresh bovine jugular vein containing a native valve was sutured into a vascular stent and then cross-linked with a 0.6% glutaraldehyde solution for 36 hours. After being hand-crimped onto a balloon catheter, the device was inserted percutaneously according to standard stent-placing techniques. The valved stent was finally deployed in the position of the native pulmonary valve of the lamb. Hemodynamic evaluation was carried out before and 2 months after implantation. Anatomic evaluation was finally performed. Percutaneous pulmonary valve replacement was successful in 5 lambs. No complications were noted. Early and late angiographic and hemodynamic studies confirmed a good position of the stents with a competent valve at the end of the protocol. One stent was slightly stenotic, with macroscopically visible calcifications. CONCLUSIONS: Nonsurgical implantation of pulmonary valves is possible in the lamb. This new technique is similar to standard stent implantation. Thus, it should be feasible in humans, in whom it will lead to a significant reduction of reoperations in patients in need of pulmonary valve replacement.

Angiography↗